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Sample records for binary miscibility gap

  1. The liquid metastable miscibility gap in Cu-based systems

    DEFF Research Database (Denmark)

    Curiotto, S.; Greco, R.; Pryds, Nini

    2007-01-01

    . In order to predict the phase equilibria and the mechanisms of microstructure formation, a determination of the metastable monotectics in the phase diagrams is essential. This paper focuses on the up-to-date findings on the Cu–Co, Cu–Fe and Cu–Co–Fe metastable miscibility gap in the liquid phase...

  2. Direct Measurement of the Metastable Liquid Miscibility Gap in Fe-Co-Cu Ternary Alloy System

    Institute of Scientific and Technical Information of China (English)

    CAO Chong-De; Georg P.G(O)RLER

    2005-01-01

    @@ The metastable liquid-liquid phase separation in undercooled Fe-Co-Cu ternary alloy melts (XCu = 0.10-0.84;XCo:XFe = 1:3,1:1 and 3:1) is investigated by differential thermal analysis in combination with glass fluxing technique. In almost every case, the undercooling of the homogeneous alloy melt was sufficient to reach the boundary line of the submerged miscibility gap. The differential-thermal-analysis signals indicate that this separation into a (Fe, Co)-rich liquid phase L1 and a Cu-rich liquid L2 is exothermic and proceeds until the rapid solidification of the L1 phase occurs. At a given Cu concentration and with the increase of Co content, the phase separation temperatures decrease monotonically between the corresponding values of the boundary systems Fe-Cu and Co-Cu. The boundary lines of the miscibility gap, which are determined for the three quasi-binary cross-sections of the (Fe, Co)-Cu alloy system, show remarkably flat domes. The occurrence of the liquid phase separation shows an evident influence on the subsequent γ-Fe(Co, Cu)→α-Fe(Co, Cu) solid phase transformation.

  3. The Miscibility of PCBM in Low Band-Gap Conjugated Polymers in Organic Photovoltaics

    Science.gov (United States)

    Chen, Huipeng; You, Wei; Peet, Jeff; Azoulay, Jason; Bazan, Guillermo; Dadmun, Mark

    2012-02-01

    Understanding the morphology of the photoactive layer in organic photovoltaics (OPVs) is essential to optimizing conjugated polymer-based solar cells to meet the targeted efficiency of 10%. The miscibility and interdiffusion of components are among the key elements that impact the development of morphology and structure in OPV active layers. This study uses neutron reflectivity to correlate the structure of low band gap polymers to their miscibility with PCBM. Several low band gap polymers that exhibit power conversion efficiencies exceeding 7%, including PBnDT-DTffBT were examined. The intermixing of low band-gap polymer and PCBM bilayers was monitored by neutron reflectivity before and after thermal annealing, providing quantification of the miscibility and interdiffusion of PCBM within the low band gap polymer layer. These results indicate that the miscibility of PCBM ranges from 3% to 26% with the low band-gap polymers studied. The correlation between low band gap polymer structure and miscibility of PCBM will also be discussed.

  4. Study on the nonexistence of liquid miscibility gap in the Ce-Mn system

    Directory of Open Access Journals (Sweden)

    Tang C.

    2007-01-01

    Full Text Available To ascertain whether the liquid miscibility gap exists in the Ce-Mn system, 3 key alloys are prepared by arc melting the pure elements, annealed at specified temperature for 20 minutes, quenched in ice water and then subjected to X-ray diffraction (XRD analysis for phase identification and to scanning electron microscopy (SEM with energy dispersive X-ray analysis for microstructure observation and composition analysis. The XRD examination indicated that terminal solutions based on Ce and Mn exist in the water-quenched alloys. No compound was detected. Microstructure observation and composition analysis indicate the nonexistence of the liquid miscibility gap. The newly assessed Ce-Mn phase diagram was presented. .

  5. Low temperature synthesis of Ru–Cu alloy nanoparticles with the compositions in the miscibility gap

    Energy Technology Data Exchange (ETDEWEB)

    Martynova, S.A. [Nicolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Filatov, E.Yu., E-mail: decan@niic.nsc.ru [Nicolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Korenev, S.V.; Kuratieva, N.V. [Nicolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Sheludyakova, L.A. [Nicolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Plusnin, P.E.; Shubin, Yu.V. [Nicolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Slavinskaya, E.M. [Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090 (Russian Federation); Boronin, A.I. [Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2014-04-01

    A complex salt [Ru(NH{sub 3}){sub 5}Cl][Cu(C{sub 2}O{sub 4}){sub 2}H{sub 2}O]—the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P2{sub 1}/n. Thermal properties of the prepared salt were examined in different atmospheres (helium, hydrogen, oxygen). Thermal decomposition of the precursor in inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 12 at% of copper) metastable solid solution Cu{sub x}Ru{sub 1−x} (based on Ru structure) were optimized, what is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. Catalytic properties of copper–ruthenium oxide composite were tested in catalytic oxidation of CO. - Highlights: • We synthesized new precursor of CuRu metastable nanoalloys. • Thermal properties of the prepared salt were examined in different atmospheres. • Thermodestruction mechanism of precursor are studied. • Cu{sub 0.12}Ru{sub 0.88} nanoalloy with the compositions in the miscibility gap is obtained. • Catalytic conversion of CO on copper–ruthenium oxide composite were examined.

  6. Size-dependent spinodal and miscibility gaps for intercalation in nanoparticles.

    Science.gov (United States)

    Burch, Damian; Bazant, Martin Z

    2009-11-01

    Using a recently proposed mathematical model for intercalation dynamics in phase-separating materials ( Singh , G. K. , Ceder , G. and Bazant , M. Z. Electrochimica Acta 2008 , 53 , 7599. ), we show that the spinodal and miscibility gaps generally shrink as the host particle size decreases to the nanoscale. Our work is motivated by recent experiments on the high-rate Li-ion battery material LiFePO(4); this serves as the basis for our examples, but our analysis and conclusions apply to any intercalation material. We describe two general mechanisms for the suppression of phase separation in nanoparticles, (i) a classical bulk effect, predicted by the Cahn-Hilliard equation in which the diffuse phase boundary becomes confined by the particle geometry; and (ii) a novel surface effect, predicted by chemical-potential-dependent reaction kinetics, in which insertion/extraction reactions stabilize composition gradients near surfaces in equilibrium with the local environment. Composition-dependent surface energy and (especially) elastic strain can contribute to these effects but are not required to predict decreased spinodal and miscibility gaps at the nanoscale.

  7. Modeling and Simulation of the Microstructure Evolution during a Cooling of Immiscible Alloys in the Miscibility Gap

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The microstructure development during a cooling period of alloys being immiscible in the liquid state such as AlPb or Al-Bi has gained renewed scientific and technical interest during the last decades. Experiments have been performed to investigate the phase transformation kinetics in the liquid miscibility gap and numerical models have been developed to simulate and analyze the solidification process. The recently developed computational modeling techniques can, to some extent, be applied to describe the decomposition, the spatial phase separation and the microstructure evolution during a cooling period of an immiscible alloy through the miscibility gap. This article overviews the researches in this field.

  8. Microstructure evolution of immiscible alloys during rapid cooling through miscibility gap

    Institute of Scientific and Technical Information of China (English)

    刘源; 郭景杰; 贾均; 李言祥; 赵九洲

    2002-01-01

    A numerical model was developed to describe the coarsening of the second phase droplets under the common action of nucleation, diffusional growth and Brownian collision between minority phase droplets during rapidly cooling a hypermonotectic alloy through its miscibility gap. The simulated results show that Brownian motion is an important factor influencing the coarsening process. A faster cooling rate leads the supersaturation of the matrix liquid and the nucleation rate to grow up to a higher level, but leads to a smaller droplet radius and a higher number density. This model is used to predict the microstructural evolution of melt-spun Al-30%In ribbon. The model reflects the real physical processes well and is expected to be applicable to other immiscible alloys or other preparing processes.

  9. A miscibility gap in LiF-BeF₂ and LiF-BeF₂-ThF₄

    NARCIS (Netherlands)

    Meer, J.P.M. van der; Konings, R.J.M.; Jacobs, M.H.G.; Oonk, H.A.J.

    2005-01-01

    LiF BeF₂ and LiF BeF₂ ThF₄ are key systems for Molten Salt Reactor fuel. The liquid phase of these systems has been assessed using Redlich Kister polynomials. The result shows a miscibility gap on the BeF₂-rich side. This has never been proven experimentally. Nevertheless, evidence for a two liquids

  10. Estimation of CE–CVM energy parameters from miscibility gap data

    Indian Academy of Sciences (India)

    G Srinivasa Gupta; G Vamsi Madhav; A Pandey; B Nageswara Sarma; S Lele

    2005-04-01

    The powerful framework of cluster expansion–cluster variation methods (CE–CVM) expresses alloy free energy in terms of energy (model) parameters, macroscopic variables (composition and temperature) and microscopic variables (correlation functions). A simultaneous optimization of thermodynamic and phase equilibria data using CE–CVM is critically dependent on giving good initial values of energy parameters, macroscopic and microscopic variables, respectively. No standard method for obtaining the initial values of the energy parameters is available in literature. As a starting point, a method has been devised to estimate the values of energy parameters from consolute point (miscibility gap maximum) data. Empirical relations among energy parameters, temperature (c), composition (c) and 2}/2 at the consolute point, have been developed using CE–CVM free energy functions for bcc and fcc structures in the tetrahedron and tetrahedron–octahedron approximations, respectively. Thus from the observed data of c, c and 2}/2 in the above relations, good initial values of energy parameters can be obtained. Further, a necessary modification to the classical NR method for solving simultaneous nonlinear/transcendental equations with a double root in one variable and a simple root in the other has been presented.

  11. Evidence of a Surface-Mediated Magnetically Induced Miscibility Gap in Co-Pt Alloy Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Rooney, P.W.; Shapiro, A.L.; Tran, M.Q.; Hellman, F. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

    1995-08-28

    (100) and (111) oriented single-crystal CoPt{sub 3} films were deposited over a range of growth temperatures from {minus}50 to 800 {degree}C. The Curie temperature is increased by 200 {degree}C over the value expected for the homogeneous alloy in the as-deposited films (of both orientations) grown near 400 {degree}C. We interpret this as evidence for a previously unobserved, surface-mediated, magnetically driven miscibility gap in vapor-deposited CoPt{sub 3} films. Large perpendicular magnetic anisotropy is also observed in the as-deposited films (of both orientations) grown near 400 {degree}C.

  12. Spin-dipole oscillation and polarizability of a binary Bose-Einstein condensate near the miscible-immiscible phase transition

    Science.gov (United States)

    Bienaimé, Tom; Fava, Eleonora; Colzi, Giacomo; Mordini, Carmelo; Serafini, Simone; Qu, Chunlei; Stringari, Sandro; Lamporesi, Giacomo; Ferrari, Gabriele

    2016-12-01

    We report on the measurement of the spin-dipole (SD) polarizability and of the frequency of the SD oscillation of a two-component Bose-Einstein condensate of sodium atoms occupying the |3 2S1 /2,F =1 ,mF=±1 > hyperfine states. This binary spin mixture presents the important properties of being, at the same time, fully miscible and rid of the limit set by buoyancy. It is also characterized by a huge enhancement of the SD polarizability and by the consequent softening of the frequency of the SD oscillation, due to the vicinity to the transition to the immiscible phase. The experimental data are successfully compared with the predictions of theory.

  13. Microstructure Evolution in a Rapidly Solidified Cu85Fe15 Alloy Undercooled into the Metastable Miscibility Gap

    Institute of Scientific and Technical Information of China (English)

    Jie HE; Jiuzhou ZHAO

    2005-01-01

    A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to investigate the process of liquid-liquid phase transformation. The numerical results indicate that the minority phase droplets are nucleated in a temperature region around the peak of the supersaturation. The average radius of the Fe-rich droplets decreases and the number density of the minority phase droplets increases with decreasing the atomized droplet size.The simulated results were compared with the experimental ones. The kinetic process of the liquid-liquid phase transformation was discussed in detail.

  14. Thermodynamic coarsening arrested by viscous fingering in partially miscible binary mixtures

    Science.gov (United States)

    Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

    2016-09-01

    We study the evolution of binary mixtures far from equilibrium, and show that the interplay between phase separation and hydrodynamic instability can arrest the Ostwald ripening process characteristic of nonflowing mixtures. We describe a model binary system in a Hele-Shaw cell using a phase-field approach with explicit dependence of both phase fraction and mass concentration. When the viscosity contrast between phases is large (as is the case for gas and liquid phases), an imposed background flow leads to viscous fingering, phase branching, and pinch off. This dynamic flow disorder limits phase growth and arrests thermodynamic coarsening. As a result, the system reaches a regime of statistical steady state in which the binary mixture is permanently driven away from equilibrium.

  15. Miscibility/stability considerations in binary solid dispersion systems composed of functional excipients towards the design of multi-component amorphous systems.

    Science.gov (United States)

    Yoo, Seung-uk; Krill, Steven L; Wang, Zeren; Telang, Chitra

    2009-12-01

    The correlations between amorphous miscibility/physical stability of binary solid dispersions (a highly crystalline additive-an amorphous polymer) and the physicochemical properties of the components were investigated. Crystalline functional excipients including surfactants, organic acids, and organic bases were prepared in binary solid dispersions in amorphous polymers by solvent evaporation method. Amorphous miscibility and physical stability of the systems were characterized using polarized light microscope, differential scanning calorimeter, and powder X-ray diffraction. Physicochemical parameters (solubility parameter (delta), hydrogen bond energy, Log P, pK(a) value as an indicator of acid-base ionic interaction, and T(g) of the dispersion as a surrogate of system's mobility) were selected as thermodynamic and kinetic factors to examine their influences on the systems' amorphous miscibility and physical stability. All systems possessing acid-base ionic interaction formed amorphous state. In the absence of the ionic interaction, solubility parameter and partition coefficient were shown to have major roles on amorphous formation. Upon storage condition at 25 degrees C/60% RH for 50 days, systems having ionic interaction and high T(g) remained in the amorphous state. This binary system study provides an insight and a basis for formation of the amorphous state of multi-component solid dispersions utilizing their physicochemical properties.

  16. Binary-disk interaction: Gap-Opening criteria

    CERN Document Server

    del Valle, Luciano

    2012-01-01

    We study the interaction of an equal mass binary with an isothermal circumbinary disk motivated by the theoretical and observational evidence of the formation of massive black holes binaries surrounded by gas, after a major merger of gas-rich galaxies. We focus on the torques that the binary produces on the disk and how the exchange of angular momentum can drive the formation of a gap on it. We propose that the angular momentum exchange between the binary and the disk is through the gravitational interaction of the binary and a (tidally formed) global non-axisymmetric perturbation in the disk. Using this gravitational interaction we derive an analytic criterion for the formation of a gap in the disk that can be expressed on the structural parameters h/a and M(< r)/M_{bin}. Using SPH simulations we show that the simulations where the binary opens a gap in the disk and the simulations where the disk does not have a gap are distributed in two well separate regions. Our analytic gap-opening criterion predicts ...

  17. Experiments and Direct Numerical Simulations of binary collisions of miscible liquid droplets with different viscosities

    CERN Document Server

    Focke, C; Kuschel, M; Sommerfeld, M

    2012-01-01

    Binary droplet collisions are of importance in a variety of practical applications comprising dispersed two-phase flows. The background of our research is the prediction of properties of particulate products formed in spray processes. To gain a more thorough understanding of the elementary sub-processes inside a spray, experiments and direct numerical simulations of binary droplet collisions are used. The aim of these investigations is to develop semi-analytical descriptions for the outcome of droplet collisions. Such collision models can then be employed as closure terms for scale-reduced simulations. In the present work we focus on the collision of droplets of different liquids. These kinds of collisions take place in every spray drying process when droplets with different solids contents collide in recirculation zones. A new experimental method has been developed allowing for high spatial and time resolved recordings via Laser-induced fluorescence. The results obtained with the proposed method will be comp...

  18. Equilibrium study between condensed phases by isoplethic thermal analysis when a miscibility gap is observed

    OpenAIRE

    Labarthe, Emilie; Bougrine, Anne-Julie; Delalu, Henri; Berthet, Jacques; Counioux, Jean-Jacques

    2009-01-01

    International audience; Isoplethic thermal analysis was used to determine the solid-liquid-liquid equilibria in the ternary system water-sodium sulfate-piperidine. The changes in state observed on the thermogram recorded during the displacement in a quasi-binary section permit the identification of the different phases and the delimitation of the corresponding equilibrium domains. Two isotherms were established at 25°C and 40°C because these temperatures frame the peritectic decomposition of ...

  19. Binary-disk interaction. II. Gap-opening criteria for unequal-mass binaries

    Energy Technology Data Exchange (ETDEWEB)

    Del Valle, Luciano; Escala, Andrés, E-mail: ldelvalleb@gmail.com [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)

    2014-01-01

    We study the interaction of an unequal-mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a supermassive black hole binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts on the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong nonaxisymmetric density perturbation that is produced in the disk, in response to the presence of the binary. Using smoothed particle hydrodynamics numerical simulations, we test two gap-opening criteria, one that assumes the geometry of the density perturbation is an ellipsoid/thick spiral and another that assumes a flat spiral geometry for the density perturbation. We find that the flat spiral gap-opening criterion successfully predicts which simulations will have a gap in the disk and which will not. We also study the limiting cases predicted by the gap-opening criteria. Since the viscosity in our simulations is considerably smaller than the expected value in the nuclear regions of gas-rich merging galaxies, we conclude that in such environments the formation of a circumbinary gap is unlikely.

  20. The role of magnetism in the formation of the two-phase miscibility gap in β Cu–Al–Mn

    Energy Technology Data Exchange (ETDEWEB)

    Lanzini, Fernando, E-mail: flanzini@exa.unicen.edu.ar [Instituto de Física de Materiales Tandil (IFIMAT), Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Pinto 399, 7000 Tandil (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Alés, Alejandro [Instituto de Física de Materiales Tandil (IFIMAT), Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Pinto 399, 7000 Tandil (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina)

    2015-12-01

    A theoretical study of the ground state properties of alloys with compositions along the pseudobinary line Cu{sub 3}Al–Cu{sub 2}AlMn is presented. Cohesive energies, lattice parameters and magnetic moments of the two limiting compounds and three intermediate compositions are calculated by means of density functional theory. In order to evaluate the role of magnetism, both the spin-polarized (SP) and the non spin-polarized (NSP) cases have been considered. It is shown that magnetism plays a central role on the stabilization of the L2{sub 1} crystal structure in Cu{sub 2}AlMn, and in the formation of the miscibility gap in Cu{sub 3}Al–Cu{sub 2}AlMn. The considerable lattice mismatch between the end compounds can be attributed also to magnetic effects. - Highlights: • Alloys with compositions Cu{sub 3−x}AlMn{sub x} were studied by first principles methods. • Both spin-polarized (SP) and non-spin-polarized (NSP) calculations were done. • Cohesive energies, lattice parameters and magnetic moments were determined. • The phase separation Cu{sub 3}Al+Cu{sub 2}AlMn is attributable to magnetic effects. • In the NSP case, L2{sub 1} Cu{sub 2}AlMn is predicted to be unstable against the F43m structure.

  1. Miscibility of Two Components in a Binary Mixture of 9-Phenyl Anthracene Mixed with Stearic Acid or Polymethyl Methacrylate at Air-Water Interface

    Institute of Scientific and Technical Information of China (English)

    P. K. Paul; Md. N. Islam; D. Bhattacharjee; S. A. Hussain

    2007-01-01

    We report the miscibility characteristics of two components in a binary mixture of 9-phenyl anthracene (PA) mixed with stearic acid (SA) or polymethyl methacrylate (PMMA). The behaviour of surface pressure versus area per molecule isotherms reveal that the area per molecule decreases systematically with increasing molefractions of PA. The characteristics of areas per molecule versus molefractions and collapse pressure vs molefraction indicate that various interactions involved among the sample and matrix molecules. The interaction scheme is found to change with the change in surface pressure and molefraction of mixing. Scanning electron microscopic study confirms the aggregation of PA molecules in the mixed films.

  2. Determination of the equilibrium miscibility gap in the Pd-Rh alloy system using metal nanopowders obtained by decomposition of coordination compounds

    Energy Technology Data Exchange (ETDEWEB)

    Shubin, Yu.V., E-mail: shubin@niic.nsc.ru; Plyusnin, P.E.; Korenev, S.V.

    2015-02-15

    Highlights: • The Pd-Rh phase diagram has been experimentally reinvestigated. • The true equilibrium was achieved with the two-way approach. • The critical point of the miscibility gap lie at 58 at.% Rh and 820 °C. - Abstract: The Pd-Rh phase diagram has been reinvestigated in the subsolidus region using X-ray diffraction, scanning and transmission electron microscopy. The true equilibrium at the miscibility boundary was achieved with the two-way approach. Nanosized powders of metastable solid solutions and two-phase palladium-rhodium mixtures were used to shorten the time required to equilibrate the system. The initial samples were prepared by decomposition of coordination compounds [Pd(NH{sub 3}){sub 2}Cl{sub 2}], [Rh(NH{sub 3}){sub 5}Cl]Cl{sub 2}, [Pd(NH{sub 3}){sub 4}]{sub 3}[Rh(NO{sub 2}){sub 6}]{sub 2} and [Pd(NH{sub 3}){sub 4}][Rh(NH{sub 3})(NO{sub 2}){sub 5}]. The obtained phase diagram exhibits miscibility gap wider than generally accepted with the critical point of solubility at 58 at.% Rh and 820 °C.

  3. Binary Disk interaction II: Gap-Opening criteria for unequal mass binaries

    CERN Document Server

    del Valle, Luciano

    2013-01-01

    We study the interaction between an unequal mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a SMBH binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts onto the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong non-axisymmetric density perturbation that is produced in the disk, as response to the presence of the binary. Using SPH numerical simulations we tested two gap-opening criterion, one that assumes that the geometry of the density perturbation is an ellipsoid/thick-spirals and another that assumes a geometry of flat-spirals for the density perturbation. We find that the flat-spirals gap opening criterion successfully predicts which simulations will hav...

  4. Miscibility gap and phonon thermodynamics of Fe-Au alloys studied by inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Jorge A. [Intel Corporation, Information Technology Research, Hillsboro, OR 97124 (United States); Fultz, Brent [California Institute of Technology, Department of Applied Physics and Materials Science, Pasadena, CA 91125 (United States)

    2015-07-23

    Recent measurements of the phonon spectra of several Au-rich alloys of face-centered-cubic Fe-Au using inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering are summarized. The Wills-Harrison model, accounting for charge transfer upon alloying, is used to explain the observed negative excess vibrational entropy of mixing, which increases the miscibility gap temperature in the system by an estimated maximum of 550 K and we adjudicate to a charge transfer from the Fe to the Au atoms that results in an increase in the electron density in the free-electron-like states and in stronger sd-hybridization. When Au is the solvent, this softens the Fe–Fe bonds but stiffens the Au–Au and Au–Fe bonds which results in a net stiffening relative to the elemental components.

  5. Growth of lattice-matched GaInAsP grown on vicinal GaAs(001) substrates within the miscibility gap for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Ryuji; France, Ryan M.; Geisz, John F.; Norman, Andrew G.; Steiner, Myles A.

    2017-01-01

    The growth of quaternary Ga0.68In0.32As0.35P0.65 by metal-organic vapor phase epitaxy is very sensitive to growth conditions because the composition is within a miscibility gap. In this investigation, we fabricated 1 um-thick lattice-matched GaInAsP films grown on GaAs(001) for application to solar cells. The growth temperature and substrate miscut are varied in order to characterize the effect of the surface diffusion of adatoms on the material quality of alloys. Transmission electron microscopy and two-dimensional in-situ multi-beam optical stress determine that growth temperatures of 650 degrees C and below enhance the formation of the CuPtB atomic ordering and suppress material decomposition, which is found to occur at the growth surface. The root-mean-square (RMS) roughness is reduced from 33.6 nm for 750 degrees C to 1.62 nm for 650 degrees C, determined by atomic force microscopy. Initial investigations show that the RMS roughness can be further reduced using increased miscut angle, and substrates miscut toward (111)A, leading to an RMS roughness of 0.56 nm for the sample grown at 600 degrees C on GaAs miscut 6 degrees toward (111)A. Using these conditions, we fabricate an inverted hetero-junction 1.62 eV Ga0.68In0.32As0.35P0.65 solar cell without an anti-reflection coating with a short-circuit current density, open-circuit voltage, fill factor, and efficiency of 12.23 mA/cm2, 1.12 V, 86.18%, and 11.80%, respectively.

  6. Growth of lattice-matched GaInAsP grown on vicinal GaAs(001) substrates within the miscibility gap for solar cells

    Science.gov (United States)

    Oshima, Ryuji; France, Ryan M.; Geisz, John F.; Norman, Andrew G.; Steiner, Myles A.

    2017-01-01

    The growth of quaternary Ga0.68In0.32As0.35P0.65 by metal-organic vapor phase epitaxy is very sensitive to growth conditions because the composition is within a miscibility gap. In this investigation, we fabricated 1 μm-thick lattice-matched GaInAsP films grown on GaAs(001) for application to solar cells. The growth temperature and substrate miscut are varied in order to characterize the effect of the surface diffusion of adatoms on the material quality of alloys. Transmission electron microscopy and two-dimensional in-situ multi-beam optical stress determine that growth temperatures of 650 °C and below enhance the formation of the CuPtB atomic ordering and suppress material decomposition, which is found to occur at the growth surface. The root-mean-square (RMS) roughness is reduced from 33.6 nm for 750 °C to 1.62 nm for 650 °C, determined by atomic force microscopy. Initial investigations show that the RMS roughness can be further reduced using increased miscut angle, and substrates miscut toward (111)A, leading to an RMS roughness of 0.56 nm for the sample grown at 600 °C on GaAs miscut 6° toward (111)A. Using these conditions, we fabricate an inverted hetero-junction 1.62 eV Ga0.68In0.32As0.35P0.65 solar cell without an anti-reflection coating with a short-circuit current density, open-circuit voltage, fill factor, and efficiency of 12.23 mA/cm2, 1.12 V, 86.18%, and 11.80%, respectively.

  7. Flexural vibration band gaps in thin plates with two-dimensional binary locally resonant structures

    Institute of Scientific and Technical Information of China (English)

    Yu Dian-Long; Wang Gang; Liu Yao-Zong; Wen Ji-Hong; Qiu Jing

    2006-01-01

    The complete flexural vibration band gaps are studied in the thin plates with two-dimensional binary locally resonant structures, i.e. the composite plate consisting of soft rubber cylindrical inclusions periodically placed in a host material. Numerical simulations show that the low-frequency gaps of flexural wave exist in the thin plates. The width of the first gap decreases monotonically as the matrix density increases. The frequency response of the finite periodic thin plates is simulated by the finite element method, which provides attenuations of over 20dB in the frequency range of the band gaps. The findings will be significant in the application of phononic crystals.

  8. Dynamics of binary-disk interaction. 1: Resonances and disk gap sizes

    Science.gov (United States)

    Artymowicz, Pawel; Lubow, Stephen H.

    1994-01-01

    We investigate the gravitational interaction of a generally eccentric binary star system with circumbinary and circumstellar gaseous disks. The disks are assumed to be coplanar with the binary, geometrically thin, and primarily governed by gas pressure and (turbulent) viscosity but not self-gravity. Both ordinary and eccentric Lindblad resonances are primarily responsible for truncating the disks in binaries with arbitrary eccentricity and nonextreme mass ratio. Starting from a smooth disk configuration, after the gravitational field of the binary truncates the disk on the dynamical timescale, a quasi-equilibrium is achieved, in which the resonant and viscous torques balance each other and any changes in the structure of the disk (e.g., due to global viscous evolution) occur slowly, preserving the average size of the gap. We analytically compute the approximate sizes of disks (or disk gaps) as a function of binary mass ratio and eccentricity in this quasi-equilibrium. Comparing the gap sizes with results of direct simulations using the smoothed particle hydrodynamics (SPH), we obtain a good agreement. As a by-product of the computations, we verify that standard SPH codes can adequately represent the dynamics of disks with moderate viscosity, Reynolds number R approximately 10(exp 3). For typical viscous disk parameters, and with a denoting the binary semimajor axis, the inner edge location of a circumbinary disk varies from 1.8a to 2.6a with binary eccentricity increasing from 0 to 0.25. For eccentricities 0 less than e less than 0.75, the minimum separation between a component star and the circumbinary disk inner edge is greater than a. Our calculations are relevant, among others, to protobinary stars and the recently discovered T Tau pre-main-sequence binaries. We briefly examine the case of a pre-main-sequence spectroscopic binary GW Ori and conclude that circumbinary disk truncation to the size required by one proposed spectroscopic model cannot be due to

  9. Spreading of miscible liquids

    Science.gov (United States)

    Walls, Daniel J.; Haward, Simon J.; Shen, Amy Q.; Fuller, Gerald G.

    2016-05-01

    Miscible liquids commonly contact one another in natural and technological situations, often in the proximity of a solid substrate. In the scenario where a drop of one liquid finds itself on a solid surface and immersed within a second, miscible liquid, it will spread spontaneously across the surface. We show experimental findings of the spreading of sessile drops in miscible environments that have distinctly different shape evolution and power-law dynamics from sessile drops that spread in immiscible environments, which have been reported previously. We develop a characteristic time to scale radial data of the spreading sessile drops based on a drainage flow due to gravity. This time scale is effective for a homologous subset of the liquids studied. However, it has limitations when applied to significantly chemically different, yet miscible, liquid pairings; we postulate that the surface energies between each liquid and the solid surface becomes important for this other subset of the liquids studied. Initial experiments performed with pendant drops in miscible environments support the drainage flow observed in the sessile drop systems.

  10. OIL DISPLACEMENT IN MISCIBLE CONDITION

    Directory of Open Access Journals (Sweden)

    Ivanka Juttner

    1997-12-01

    Full Text Available After primary oil recovery in reservoirs remains about 70% of unexploited oil. To improve the recovery of the remaining reserves, injection of a fluid provide the extra energy in a mchunical form. Oil displacement can he achieved by gas injection of lean natural gas, mainly methane, carbon dioxide etc. Oil displacement can be in immiscible or miscible conditions. This paper deals with mechanism of miscible gas drive. On the basis of simulation of the oil displacement process by gas injection into oil field Žutica the character of process, i. c. a degree of miscibility or immiscibility between the injected fluid and reservoir oil was determined.

  11. SDSS 1355+0856: a detached white dwarf + M star binary in the period gap discovered by the SWARMS survey

    Science.gov (United States)

    Badenes, Carles; van Kerkwijk, Marten H.; Kilic, Mukremin; Bickerton, Steven J.; Mazeh, Tsevi; Mullally, Fergal; Tal-Or, Lev; Thompson, Susan E.

    2013-03-01

    SDSS J135523.92 + 085645.4 (SDSS 1355+0856) was identified as a hot white dwarf with a companion from time-resolved Sloan Digital Sky Survey spectroscopy as part of the ongoing Sloan White Dwarf Radial velocity data Mining Survey survey. Follow-up observations with the Astrophysical Research Consortium 3.5 m telescope and the Multiple Mirror Telescope revealed weak emission lines in the central cores of the Balmer absorption lines during some phases of the orbit, but no line emission during other phases. This can be explained if SDSS 1355+0856 is a detached white dwarf + M dwarf binary similar to GD 448, where one of the hemispheres of the low-mass companion is irradiated by the proximity of the hot white dwarf. Based on the available data, we derive an orbital period of 0.114 38 ± 0.000 06 d, a primary mass of 0.46 ± 0.01 M⊙, a secondary mass between 0.083 and 0.097 M⊙, and an orbital inclination larger than 57°. This makes SDSS 1355+0856 one of the shortest period post-common envelope white dwarf + M dwarf binaries, and the record holder for the lowest mass stellar companion, which has interesting implications for our understanding of common envelope evolution and the phenomenology of cataclysmic variables. The short cooling time of the WD (25 Myr) implies that the system emerged from the common envelope phase with an orbital period very similar to what we observe today, and was born in the period gap of cataclysmic variables.

  12. Tuning the phase diagrams: the miscibility studies of multilactate liquid crystalline compounds

    Science.gov (United States)

    Bubnov, Alexej; Tykarska, Marzena; Hamplová, Věra; Kurp, Katarzyna

    2016-09-01

    Design of binary and multicomponent liquid crystalline mixtures is a very powerful tool to reach the desired self-assembling properties. Beyond many advantages, this method has a distinct negativity - it is very material-consuming. While working with unique chiral materials in the research laboratory, this problem can be solved by applying miscibility study by the contact preparation method. In this work, the miscibility studies of lactic acid derivatives and non-chiral/chiral liquid crystalline molecules of different structure have been done in order to establish the phase diagrams. Special attention is focused on the ferro(antiferro)electric smectic phases.

  13. Flow cell system for miscible displacement experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, S.H.; Kirkham, D.

    1971-02-01

    The use of a continuous graphic recording system for flow-component measurement in miscible displacement experiments is described. This system measures and continuously records radioactive tracer concentrations of effluents of miscible displacement columns. The recordings are needed breakthrough curves. The use of the system obviates fraction collectors.

  14. Viscous fingering of miscible slices

    CERN Document Server

    De Wit, A; Martin, M; Wit, Anne De; Bertho, Yann; Martin, Michel

    2005-01-01

    Viscous fingering of a miscible high viscosity slice of fluid displaced by a lower viscosity fluid is studied in porous media by direct numerical simulations of Darcy's law coupled to the evolution equation for the concentration of a solute controlling the viscosity of miscible solutions. In contrast with fingering between two semi-infinite regions, fingering of finite slices is a transient phenomenon due to the decrease in time of the viscosity ratio across the interface induced by fingering and dispersion processes. We show that fingering contributes transiently to the broadening of the peak in time by increasing its variance. A quantitative analysis of the asymptotic contribution of fingering to this variance is conducted as a function of the four relevant parameters of the problem i.e. the log-mobility ratio R, the length of the slice l, the Peclet number Pe and the ratio between transverse and axial dispersion coefficients $\\epsilon$. Relevance of the results is discussed in relation with transport of vi...

  15. The GAPS programme with HARPS-N at TNG. X. Differential abundances in the XO-2 planet-hosting binary

    Science.gov (United States)

    Biazzo, K.; Gratton, R.; Desidera, S.; Lucatello, S.; Sozzetti, A.; Bonomo, A. S.; Damasso, M.; Gandolfi, D.; Affer, L.; Boccato, C.; Borsa, F.; Claudi, R.; Cosentino, R.; Covino, E.; Knapic, C.; Lanza, A. F.; Maldonado, J.; Marzari, F.; Micela, G.; Molaro, P.; Pagano, I.; Pedani, M.; Pillitteri, I.; Piotto, G.; Poretti, E.; Rainer, M.; Santos, N. C.; Scandariato, G.; Zanmar Sanchez, R.

    2015-11-01

    Binary stars hosting exoplanets are a unique laboratory where chemical tagging can be performed to measure the elemental abundances of both stellar components with high accuracy, with the aim to investigate the formation of planets and their subsequent evolution. Here, we present a high-precision differential abundance analysis of the XO-2 wide stellar binary based on high-resolution HARPS-N at TNG spectra. Both components are very similar K-dwarfs and host planets. Since they formed presumably within the same molecular cloud, we expect that they possess the same initial elemental abundances. We investigated whether planets can cause some chemical imprints in the stellar atmospheric abundances. We measure abundances of 25 elements for both stars with a range of condensation temperature TC = 40-1741 K, achieving typical precisions of ~0.07 dex. The northern component shows abundances in all elements higher by +0.067 ± 0.032 dex on average, with a mean difference of +0.078 dex for elements with TC > 800 K. The significance of the XO-2N abundance difference relative to XO-2S is at the 2σ level for almost all elements. We discuss that this result might be interpreted as the signature of the ingestion of material by XO-2N or depletion in XO-2S that is due to locking of heavy elements by the planetary companions. We estimate a mass of several tens of M⊕ in heavy elements. The difference in abundances between XO-2N and XO-2S shows a positive correlation with the condensation temperatures of the elements, with a slope of (4.7 ± 0.9) × 10-5 dex K-1, which could mean that both components have not formed terrestrial planets, but first experienced the accretion of rocky core interior to the subsequent giant planets. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF - Fundación Galileo Galilei at the Roche de los Muchachos Observatory of the Instituto de Astrofísica de Canarias (IAC) in the

  16. Controlling radial fingering patterns in miscible confined flows.

    Science.gov (United States)

    Chen, Ching-Yao; Huang, C-W; Wang, L-C; Miranda, José A

    2010-11-01

    Injection-driven immiscible flow in radial Hele-Shaw cells results in highly ramified patterns if the injection rate is constant in time. Likewise, time-dependent gap immiscible flow in lifting Hele-Shaw cells leads to intricate morphologies if the cell's gap width grows exponentially with time. Recent studies show that the rising of these complex fingered structures can be controlled by properly adjusting the injection rate, and the time-dependent gap width. We investigate the effectiveness of these control strategies assuming that the fluids involved are miscible. Despite the absence of surface tension effects, intensive numerical simulations support the stabilizing role of these controlling protocols. Splitting, merging and competition of fingers are all inhibited. The sensitivity of the system to changes in the initial conditions and Péclet numbers is also discussed.

  17. Viscous fingering with partial miscible fluids

    Science.gov (United States)

    Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

    2015-11-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Studies of viscous fingering have focused on fluids that are either fully miscible or perfectly immiscible. In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other. Following our recent work for miscible (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a Hele-Shaw cell, when the two fluids have limited (but nonzero) solubility in one another. Partial miscibility is characterized through the design of thermodynamic free energy of the two-fluid system. We elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution.

  18. Fatty acids polymorphism and solid-state miscibility

    Energy Technology Data Exchange (ETDEWEB)

    Gbabode, Gabin [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux I, 33405 Talence (France)], E-mail: ggbabode@ulb.ac.be; Negrier, Philippe; Mondieig, Denise [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux I, 33405 Talence (France); Moreno, Evelyn; Calvet, Teresa; Cuevas-Diarte, Miquel Angel [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, 08028 Barcelona (Spain)

    2009-02-05

    The pentadecanoic acid-hexadecanoic acid (C{sub 15}H{sub 29}OOH-C{sub 16}H{sub 31}OOH) binary system is dealt with in this article. The polymorphism of 20 mixed materials has been investigated combining calorimetric measurements, isothermal and versus temperature X-ray powder diffraction and also FTIR spectroscopy. In particular, the cell parameters of the stable forms, temperatures and heats of phase changes for the two constituents and a proposal of phase diagram are given in this article. Three solid forms are created by mixing in addition with the four solid forms of the pure components. All these solid forms are stabilized on narrow domains of composition, implying a reduced solid-state miscibility of the pentadecanoic and hexadecanoic acids.

  19. MISCIBILITY IN COPOLYMER/HOMOPOLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming

    1988-01-01

    In order to study the miscibility of a copolymer with its corresponding homopolymers, varieties of multicomponent polymers including simple graft, multibranch, diblock, triblock and four-arm block copolymers and so-called ABCPs were synthesized and characterized. The morphologies of the blends comprising the covolymers and the corresponding homopolymers were examined by electron microscopy. It is concluded that beeides molecular weight, architecture of a copolymers has apparent effect on the miscibility, i.e. the more complex is molecular architecture, the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains. In addition, a density gradient model is suggested for describing the segment distribution of the bound and free chains in block-homopolymer systems. Using this model, Helfand's theory is extended to the blends of copolymer and homopolymer predicting the miscibility which is in good agreement with the experimental results.

  20. Miscibility of polymer blends with engineering models

    DEFF Research Database (Denmark)

    Vassilis, Harismiadis; van Bergen, A. R. D.; Goncalves, Ana Saraiva;

    1996-01-01

    The miscibility behavior of polymer blends that do not exhibit strong specific interactions is examined. Phase equilibrium calculations are presented with the van der Waals equation of state and three group-contribution models (UNIFAC, Entropic-FV, and GC-Flory). Performance of these models is al...

  1. The GAPS Programme with HARPS-N at TNG. IX. Differential abundances in the XO-2 planet hosting binary

    CERN Document Server

    Biazzo, K; Desidera, S; Lucatello, S; Sozzetti, A; Bonomo, A S; Damasso, M; Gandolfi, D; Affer, L; Boccato, C; Borsa, F; Claudi, R; Cosentino, R; Covino, E; Knapic, C; Lanza, A F; Maldonado, J; Marzari, F; Micela, G; Molaro, P; Pagano, I; Pedani, M; Pillitteri, I; Piotto, G; Poretti, E; Rainer, M; Santos, N C; Scandariato, G; Sanchez, R Zanmar

    2015-01-01

    Binary stars hosting exoplanets are a unique laboratory where chemical tagging can be performed to measure with high accuracy the elemental abundances of both stellar components, with the aim to investigate the formation of planets and their subsequent evolution. Here, we present a high-precision differential abundance analysis of the XO-2 wide stellar binary based on high resolution HARPS-N@TNG spectra. Both components are very similar K-dwarfs and host planets. Since they formed presumably within the same molecular cloud, we expect they should possess the same initial elemental abundances. We investigate if the presence of planets can cause some chemical imprints in the stellar atmospheric abundances. We measure abundances of 25 elements for both stars with a range of condensation temperature $T_{\\rm C}=40-1741$ K, achieving typical precisions of $\\sim 0.07$ dex. The North component shows abundances in all elements higher by $+0.067 \\pm 0.032$ dex on average, with a mean difference of +0.078 dex for element...

  2. Correlation Between Miscibility and Rheological Characteristics of the Polystyrene (PS) and Poly(styrene-co-acrylonitrile) (PSAN) Blends

    Science.gov (United States)

    Marwat, Zafrullah Khan; Baloch, Musa Kaleem

    2016-11-01

    Rheological measurement has been an effective technique to characterize the miscibility of polymer blends. This article investigates the viscoelastic behavior of poly(styrene) (PS) and poly(styrene-co-acrylonitrile) (PSAN) binary solutions in tetrahydrofuran (THF) relative to PS/PSAN/THF ternary solutions mainly reporting the findings of the authors involving the correlation between the miscibility and rheological behavior. Rheological properties, such as shear viscosity, and shear stress as a function of shear rate were investigated for different blend compositions. Moreover, complex viscosity, loss and storage moduli were also investigated as functions of both the frequency and blend composition. The criterion of miscibility based on the rule of mixture has been discussed. The present study revealed very small window of miscibility as only composition, 50/50 showed values close to the additivity rule or intermediate to those of the neat polymers, thereby indicating very weak interactions between the blend components. On the basis of various findings during the rheological investigation, the blend under study is classified almost immiscible. Moreover, the obtained results also suggested that the miscibility depends on the blend composition and frequency.

  3. Viscous fingering with partially miscible fluids

    Science.gov (United States)

    Fu, X.; Cueto-Felgueroso, L.; Juanes, R.

    2015-12-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Experimental and numerical studies of viscous fingering have focused on fluids that are either fully miscible (e.g. water and glycerol) or perfectly immiscible (e.g. water and oil). In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other (e.g. CO2 and water). Following our recent work for miscible systems (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a porous medium, when the two fluids have limited (but nonzero) solubility in one another. In our model, partial miscibility is characterized through the design of the thermodynamic free energy of the two-fluid system. We express the model in dimensionless form and elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution. Figure caption: final snapshots in simulations of viscous fingering with a two-fluid system mimicking that of CO2 and water. The colormap corresponds to the concentration of CO2. A band of less viscous gas phase rich in CO2 (red) displaces through the more viscous liquid phase that is undersaturated with CO2 (blue). At the fluid interface, an exchange of CO2 occurs as a result of local chemical potentials that drives the system towards thermodynamic equilibrium. This results in a shrinkage of gas phase as well as a local increase in

  4. How Pure Components Control Polymer Blend Miscibility

    Science.gov (United States)

    White, Ronald; Lipson, Jane; Higgins, Julia

    2012-02-01

    We present insight into some intriguing relationships revealed by our recent studies of polymer mixture miscibility. Applying our simple lattice-based equation of state, we discuss some of the patterns observed over a sample of experimental blends. We focus on the question of how much key information can one determine from a knowledge of just the pure components only, and further, on the role of separate enthalpic and entropic contributions to the miscibility behavior. One interesting correlation connects the value of the difference in pure component energetic parameters with that of the mixed segment interactions, suggesting new possibilities for predictive modeling. We also show how in some cases these two parameter groupings act as separate controls determining the entropy and enthalpy of mixing. Also discussed are the different patterns exhibited for UCST-type and LCST-type blends, these being revealed in some cases by simple examination of the underlying microscopic parameters.

  5. Dynamics of miscible displacements in round tubes

    Energy Technology Data Exchange (ETDEWEB)

    Meiburg, E.; Maxworthy, T.; Chen, C.Y. [Univ. of Southern California, Los Angeles, CA (United States); Petitjeans, P. [Ecole Superieure de Physique et de Chimie Industrielles, Paris (France)

    1995-12-31

    A combined experimental and numerical investigation of miscible two-phase flow in a capillary tube is reported. The fraction of fluid left behind on the wall is obtained as a function of the Peclet, Atwood, and Froude numbers. Scaling arguments are presented for two distinct flow regimes, dominated by diffusion and convection, respectively. In the latter one, an effective surface tension value can be estimated.

  6. Buoyancy-driven instability of a miscible horizontal displacement in a Hele-Shaw cell

    Science.gov (United States)

    Haudin, F.; Riolfo, L. A.; Knaepen, B.; de Wit, A.

    2012-11-01

    In Hele-Shaw cells, viscous fingers are forming when a fluid is injected into a more viscous one. If the two fluids are reversed, with the less mobile fluid injected into the low viscosity one, the situation is expected to be stable from a viscous point of view. Nevertheless, a destabilization of the interface can be observed due to a buoyancy-driven effect if a density difference exists between the two miscible fluids. As a result, the Poiseuille profile established in the gap of the cell locally destabilizes and convection rolls are forming. In a view from above, a striped pattern is observed at the miscible interface between the two fluids. To characterize the development of this instability, we have performed an experimental study of viscously stable miscible displacements in a Hele-Shaw cell with radial injection. The displacing fluids are aqueous solutions of glycerol and the displaced ones are either dyed water or dyed glycerol solutions. The way the relative properties of the two fluids is influencing the onset time of the instability and the characteristic size of the pattern is studied. The influence of the gap width and of the flow rate on the buoyantly unstable dynamics is also characterized.

  7. Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride)/acrylic rubber/clay nanocomposite hybrid.

    Science.gov (United States)

    Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

    2014-01-01

    In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules.

  8. Estimation of minimum miscibility pressure (MMP) of CO2 and liquid n-alkane systems using an improved MRI technique.

    Science.gov (United States)

    Liu, Yu; Jiang, Lanlan; Song, Yongchen; Zhao, Yuechao; Zhang, Yi; Wang, Dayong

    2016-02-01

    Minimum miscible pressure (MMP) of gas and oil system is a key parameter for the injection system design of CO2 miscible flooding. Some industrial standard approaches such as the experiment using a rising bubble apparatus (RBA), the slim tube tests (STT), the pressure-density diagram (PDD), etc. have been applied for decades to determine the MMP of gas and oil. Some theoretical or experiential calculations of the MMP were also applied to the gas-oil miscible system. In the present work, an improved technique based on our previous research for the estimation of the MMP by using magnetic resonance imaging (MRI) was proposed. This technique was then applied to the CO2 and n-alkane binary and ternary systems to observe the mixing procedure and to study the miscibility. MRI signal intensities, which represent the proton concentration of n-alkane in both the hydrocarbon rich phase and the CO2 rich phase, were plotted as a reference for determining the MMP. The accuracy of the MMP obtained by using this improved technique was enhanced comparing with the data obtained from our previous works. The results also show good agreement with other established techniques (such as the STT) in previous published works. It demonstrates increases of MMPs as the temperature rise from 20 °C to 37.8 °C. The MMPs of CO2 and n-alkane systems are also found to be proportional to the carbon number in the range of C10 to C14.

  9. Experimental study on viscous fingering with partial miscible fluids

    Science.gov (United States)

    Suzuki, Ryuta; Nagatsu, Yuichiro; Mishra, Manoranjan; Ban, Takahiko

    2016-11-01

    Viscous fingering (VF) instability occurs when a more viscous fluid is displaced by a less viscous one in porous media or Hele-Shaw cells. So far, studies of VF have focused on fluids that are either fully miscible or immiscible. However, little attention has been paid to VF in partially miscible fluids. Here, we have experimentally investigated VF in a radial Hele-Shaw cell using an aqueous two phase system (Ban et al. Soft Matter, 2012) which is an example of partially miscible fluids system. We have found novel instabilities that are counter-intuitive in miscible and immiscible systems. These include multiple droplets formation for low flow rate and widening of fingers at intermediate flow rate. The occurrence of the new instability patterns is induced by Korteweg effect in which convection is induced during phase separation in partially miscible systems.

  10. Existence domains for invariant reactions in binary regular solution phase diagrams exhibiting two phases

    Indian Academy of Sciences (India)

    B Nageswara Sarma; S Srinivas Prasad; S Vijayvergiya; V Bharath Kumar; S Lele

    2003-06-01

    The thermodynamic origin of various types of phase diagrams in simple binary systems exhibiting two phases (e.g. a liquid and a solid phase) has been examined using the regular solution model. The necessary conditions for the occurrence of each of these types are identified in terms of the appropriate intersections of the miscibility gap boundaries (in solid/liquid phases) and the liquidus/solidus/iso- curves. Thus, the regions of occurrence of the different types of possible phase diagrams in the space of the regular solution interchange energy parameters (, ) are clearly delineated. This analysis makes it easier to make intelligent initial selections of model (energy) parameters for their optimization in the calculation of phase diagrams using thermodynamic models such as CALPHAD/CVM.

  11. Miscible, porous media displacements with density stratification.

    Science.gov (United States)

    Riaz, Amir; Meiburg, Eckart

    2004-11-01

    High accuracy, three-dimensional numerical simulations of miscible displacements with gravity override, in both homogeneous and heterogeneous porous media, are discussed for the quarter five-spot configuration. The influence of viscous and gravitational effects on the overall displacement dynamics is described in terms of the vorticity variable. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Peclet number is enhanced due to the higher flow rate. Although this effect plays a dominant role in homogeneous flows, it is suppressed to some extent in heterogeneous displacements. This is a result of coupling between the viscous and permeability vorticity fields. When the viscous wavelength is much larger than the permeability wavelength, gravity override becomes more effective because coupling between the viscous and permeability vorticity fields is less pronounced. Buoyancy forces of a certain magnitude can lead to a pinch-off of the gravity layer, thereby slowing it down.

  12. XMM-NEWTON MONITORING OF THE CLOSE PRE-MAIN-SEQUENCE BINARY AK SCO. EVIDENCE OF TIDE-DRIVEN FILLING OF THE INNER GAP IN THE CIRCUMBINARY DISK

    Energy Technology Data Exchange (ETDEWEB)

    Gomez de Castro, Ana Ines [S. D. Astronomia y Geodesia and Instituto de Matematica Interdisciplinar, Fac. de CC Matematicas, Universidad Complutense, E-28040 Madrid (Spain); Lopez-Santiago, Javier [Departamento de Astrofisica, Fac de CC Fisicas, Universidad Complutense, E-28040 Madrid (Spain); Talavera, Antonio [European Space Astronomy Center, Villanueva de la Canada, E-28691, Madrid (Spain); Sytov, A. Yu.; Bisikalo, D. [Institute of Astronomy of the Russian Academy of Sciences, Pyatnitskaya St. 48, 109017 Moscow (Russian Federation)

    2013-03-20

    AK Sco stands out among pre-main-sequence binaries because of its prominent ultraviolet excess, the high eccentricity of its orbit, and the strong tides driven by it. AK Sco consists of two F5-type stars that get as close as 11 R{sub *} at periastron passage. The presence of a dense (n{sub e} {approx} 10{sup 11} cm{sup -3}) extended envelope has been unveiled recently. In this article, we report the results from an XMM-Newton-based monitoring of the system. We show that at periastron, X-ray and UV fluxes are enhanced by a factor of {approx}3 with respect to the apastron values. The X-ray radiation is produced in an optically thin plasma with T {approx} 6.4 Multiplication-Sign 10{sup 6} K and it is found that the N{sub H} column density rises from 0.35 Multiplication-Sign 10{sup 21} cm{sup -2} at periastron to 1.11 Multiplication-Sign 10{sup 21} cm{sup -2} at apastron, in good agreement with previous polarimetric observations. The UV emission detected in the Optical Monitor band seems to be caused by the reprocessing of the high-energy magnetospheric radiation on the circumstellar material. Further evidence of the strong magnetospheric disturbances is provided by the detection of line broadening of 278.7 km s{sup -1} in the N V line with Hubble Space Telescope/Space Telescope Imaging Spectrograph. Numerical simulations of the mass flow from the circumbinary disk to the components have been carried out. They provide a consistent scenario with which to interpret AK Sco observations. We show that the eccentric orbit acts like a gravitational piston. At apastron, matter is dragged efficiently from the inner disk border, filling the inner gap and producing accretion streams that end as ring-like structures around each component of the system. At periastron, the ring-like structures come into contact, leading to angular momentum loss, and thus producing an accretion outburst.

  13. Nanoscale Infrared, Thermal, and Mechanical Characterization of Telaprevir-Polymer Miscibility in Amorphous Solid Dispersions Prepared by Solvent Evaporation.

    Science.gov (United States)

    Li, Na; Taylor, Lynne S

    2016-03-07

    Miscibility is of great interest for pharmaceutical systems, in particular, for amorphous solid dispersions, as phase separation can lead to a higher tendency to crystallize, resulting in a loss in solubility, decreased dissolution rate, and compromised bioavailability. The purpose of this study was to investigate the miscibility behavior of a model poorly water-soluble drug, telaprevir (TPV), with three different polymers using atomic force microscopy-based infrared, thermal, and mechanical analysis. Standard atomic force microscopy (AFM) imaging together with nanoscale infrared spectroscopy (AFM-IR), nanoscale thermal analysis (nanoTA), and Lorentz contact resonance (LCR) measurements were used to evaluate the miscibility behavior of TPV with three polymers, hydroxypropyl methylcellulose (HPMC), HPMC acetate succinate (HPMCAS), and poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA), at different drug to polymer ratios. Phase separation was observed with HPMC and PVPVA at drug loadings above 10%. For HPMCAS, a smaller miscibility gap was observed, with phase separation being observed at drug loadings higher than ∼30-40%. The domain size of phase-separated regions varied from below 50 nm to a few hundred nanometers. Localized infrared spectra, nano-TA measurements, images from AFM-based IR, and LCR measurements showed clear contrast between the continuous and discrete domains for these phase-separated systems, whereby the discrete domains were drug-rich. Fluorescence microscopy provided additional evidence for phase separation. These methods appear to be promising to evaluate miscibility in drug-polymer systems with similar Tgs and submicron domain sizes. Furthermore, such findings are of obvious importance in the context of contributing to a mechanistic understanding of amorphous solid dispersion phase behavior.

  14. An Improved CO2-Crude Oil Minimum Miscibility Pressure Correlation

    Directory of Open Access Journals (Sweden)

    Hao Zhang

    2015-01-01

    Full Text Available Minimum miscibility pressure (MMP, which plays an important role in miscible flooding, is a key parameter in determining whether crude oil and gas are completely miscible. On the basis of 210 groups of CO2-crude oil system minimum miscibility pressure data, an improved CO2-crude oil system minimum miscibility pressure correlation was built by modified conjugate gradient method and global optimizing method. The new correlation is a uniform empirical correlation to calculate the MMP for both thin oil and heavy oil and is expressed as a function of reservoir temperature, C7+ molecular weight of crude oil, and mole fractions of volatile components (CH4 and N2 and intermediate components (CO2, H2S, and C2~C6 of crude oil. Compared to the eleven most popular and relatively high-accuracy CO2-oil system MMP correlations in the previous literature by other nine groups of CO2-oil MMP experimental data, which have not been used to develop the new correlation, it is found that the new empirical correlation provides the best reproduction of the nine groups of CO2-oil MMP experimental data with a percentage average absolute relative error (%AARE of 8% and a percentage maximum absolute relative error (%MARE of 21%, respectively.

  15. Process for increasing oil recovery by miscible displacement

    Energy Technology Data Exchange (ETDEWEB)

    Kiel, O.M.; Malinowsky, C.F.

    1966-08-02

    This is a miscible displacement method which involves a linear, gas-driven gravity-controlled flow mechanism. The formation is fractured and a condensible gas is injected into the fracture which has a substantial degree of miscibility with the reservoir oil. Thereafter a relatively non-condensible gas is injected through the fracture and into the reservoir. The volume of the non-condensible gas is sufficient to raise the reservoir pressure at least 50 psi above the vapor pressure of the condensible gas. Injection of the non-condensible gas is then stopped and oil is produced through the fracture with a controlled back pressure to offset the tendency of the miscible liquid to finger through the reservoir oil. (7 claims)

  16. Phase equilibria study in binary systems (tetra-n-butylphosphonium tosylate ionic liquid + 1-alcohol, or benzene, or n-alkylbenzene).

    Science.gov (United States)

    Domańska, Urszula; Paduszyński, Kamil

    2008-09-04

    Ambient pressure (solid + liquid) equilibria (SLE) and (liquid + liquid) equilibria (LLE) of binary systems--ionic liquid (IL) tetra- n-butylphosphonium p-toluenesulfonate + 1-alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol), benzene, or n-alkylbenzene (toluene, ethylbenzene, n-propylbenzene)-have been determined by using dynamic method in a broad range of mole fractions and temperatures from 250 to 335 K. For binaries containing alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. Only in the case of system [IL + n-propylbenzene] was mutual immiscibility with an upper critical solution temperature (UCST) with low solubility of the IL in the alcohol and high solubility of the alcohol in the IL detected. The basic thermal properties of pure IL, i.e., melting and glass-transition temperatures as well as enthalpy of melting, have been measured with differential scanning microcalorimetry technique (DSC). Well-known UNIQUAC, Wilson, NRTL, NRTL1, and NRTL2 equations have been fitted to obtain experimental data sets. For the system containing immiscibility gap [IL + n-propylbenzene], parameters of the equations have been derived only from SLE data. As a measure of goodness of correlations, root-mean square deviations of temperature have been used. These experimental results were compared to the previously measured binary systems with tetra- n-butylphosphonium methanesulfonate. Changing anion from methanesulfonate to p-toluenesulfonate decreases solubilities in systems with alcohols and increases the solubilities in binary systems with benzene and alkylbenzenes.

  17. Effective Algorithm for Calculation of Minimum Miscibility Pressure

    DEFF Research Database (Denmark)

    Jessen, Kristian; Michelsen, Michael Locht; Stenby, Erling Halfdan

    1998-01-01

    is introduced to describe and locate the sequence of nc- 1 key tie lines controlling the development of miscibility. In this new formulation, a number of numerical weaknesses of the original approach have been eliminated resulting in a robust and highly efficient algorithm. The computation time is reduced...

  18. Global Approach for Calculation of Minimum Miscibility Pressure

    DEFF Research Database (Denmark)

    Jessen, Kristian; Michelsen, Michael Locht; Stenby, Erling Halfdan

    1998-01-01

    of minimum miscibility pressure, Fluid Phase Equilibria, 139 (1997) 101-124]. In this work a new global approach is introduced. A number of deficiencies of the sequential approach have been eliminated resulting in a robust and highly efficient algorithm. The time consumption for calculation of the MMP...

  19. Miscibility evolution of polycarbonate/polystyrene blends during compounding

    DEFF Research Database (Denmark)

    Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib

    2002-01-01

    polymer in the other. The observed solubility strongly depends on blend composition and blending method. The T-g measurements showed maximum mutual solubility around 50/50 composition. The miscibility of PC/PS blended after the third stage (melt injection molding) was higher than that after the first...... stages (melt extrusion) and the second stages (remelt extrusion)....

  20. Learning to assign binary weights to binary descriptor

    Science.gov (United States)

    Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

    2016-10-01

    Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

  1. Miscible transfer of solute in different types of rough fractures: from random to multiscale fracture walls heights

    CERN Document Server

    Auradou, Harold; Chertcoff, Ricardo; D'Angelo, Maria Veronica; Hulin, Jean-Pierre; Ippolito, Irene

    2009-01-01

    Miscible tracer dispersion measurements in transparent model fractures with different types of wall roughness are reported. The nature (Fickian or not) of dispersion is determined by studying variations of the mixing front as a function of the traveled distance but also as a function of the lateral scale over which the tracer concentration is averaged. The dominant convective dispersion mechanisms (velocity profile in the gap, velocity variations in the fracture plane) are established by comparing measurements using Newtonian and shear thinning fluids. For small monodisperse rugosities, front spreading is diffusive with a dominant geometrical dispersion (dispersion coefficient $D \\propto Pe$) at low P\\'eclet numbers $Pe$; at higher $Pe$ values one has either $D \\propto Pe^2$ ({\\it i.e.} Taylor dispersion) for obstacles of height smaller than the gap or $D \\propto Pe^{1.35}$ for obstacles bridging the gap. For a self affine multiscale roughness like in actual rocks and a relative shear displacement $\\vec{\\delt...

  2. Phase equilibria study of the binary systems (N-hexylisoquinolinium thiocyanate ionic liquid + organic solvent or water).

    Science.gov (United States)

    Królikowska, Marta; Karpińska, Monika; Zawadzki, Maciej

    2012-04-12

    Liquid-liquid phase equilibria (LLE) of binary mixtures containing a room-temperature ionic liquid N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] with an aliphatic hydrocarbon (n-hexane, n-heptane), aromatic hydrocarbon (benzene, toluene, ethylbenzene, n-propylbenzene), cyclohexane, thiophene, water, and 1-alcohol (1-ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol) have been determined using a dynamic method from room temperature to the boiling-point of the solvent at ambient pressure. N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] has been synthesized from N-hexyl-isoquinolinium bromide as a substrate. Specific basic characterization of the new compound including NMR spectra, elementary analysis, and water content have been done. The density and viscosity of pure ionic liquid were determined over a wide temperature range from 298.15 to 348.15 K. The mutual immiscibility with an upper critical solution temperature (UCST) for the binary systems {IL + aliphatic hydrocarbon, cyclohexane, or water} was detected. In the systems of {IL + aromatic hydrocarbon or thiophene} an immiscibility gap with a lower critical solution temperature (LCST) was observed. Complete miscibility in the liquid phase, over a whole range of ionic liquid mole fraction, was observed for the binary mixtures containing IL and an 1-alcohol. For the tested binary systems with immiscibility gap {IL + aliphatic hydrocarbon, aromatic hydrocarbon, cyclohexane, thiophene, or water}, the parameters of the LLE correlation have been derived using the NRTL equation. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by simultaneous thermogravimetric/differential thermal analysis (TG/DTA) experiments.

  3. Fluid characterization for miscible EOR projects and CO2 sequestration

    DEFF Research Database (Denmark)

    Jessen, Kristian; Stenby, Erling Halfdan

    2007-01-01

    Accurate performance prediction of miscible enhanced-oil-recovery (EOR) projects or CO, sequestration in depleted oil and gas reservoirs relies in part on the ability of an equation-of-state (EOS) model to adequately represent the properties of a wide range of mixtures of the resident fluid...... and the injected fluid(s). The mixtures that form when gas displaces oil in a porous medium will, in many cases, differ significantly from compositions created in swelling tests and other standard pressure/volume/temperature (PVT) experiments. Multicontact experiments (e.g., slimtube displacements) are often used...... in the data reduction and demonstrate that for some gas/oil systems, swelling tests do not contribute to a more accurate prediction of multicontact miscibility. Finally, we report on the impact that use of EOS models based on different characterization procedures can have on recovery predictions from dynamic...

  4. XMM-Newton monitoring of the close pre-main-sequence binary AK Sco. Evidence of tide driven filling of the inner gap in the circumbinary disk

    CERN Document Server

    de Castro, Ana I Gomez; Talavera, Antonio; Sytov, A Yu; Bisikalo, D

    2013-01-01

    AK~Sco stands out among pre-main sequence binaries because of its prominent ultraviolet excess, the high eccentricity of its orbit and the strong tides driven by it. AK Sco consists of two F5 type stars that get as close as 11R$_*$ at periastron passage. The presence of a dense ($n_e \\sim 10^{11}$~cm$^{-3}$) extended envelope has been unveiled recently. In this article, we report the results from a XMM-Newton based monitoring of the system. We show that at periastron, X-ray and UV fluxes are enhanced by a factor of $\\sim 3$ with respect to the apastron values. The X-ray radiation is produced in an optically thin plasma with T$\\sim 6.4\\times 10^{6}$ K and it is found that the N$_H$ column density rises from 0.35$\\times 10^{21}$~cm$^{-2}$ at periastron to 1.11$\\times 10^{21}$~cm$^{-2}$ at apastron, in good agreement with previous polarimetric observations. The UV emission detected in the Optical Monitor band seems to be caused by the reprocessing of the high energy magnetospheric radiation on the circumstellar ...

  5. Miscibility of Polystyrene and Lighted Sulfonated Polystyrene Blends

    Science.gov (United States)

    Zhou, N. C.; Burghardt, W. R.; Composto, R. J.

    2005-03-01

    The blend miscibility of deuterated polystyrene (dPS) and lighted sulfonated poly(styrene-ran-sulfonated polystyrene) (P (S-SS)) has been examined by forward recoil spectrometry (FRES). Equilibrium coexistence compositions were determined for dPS:P(S-SSx) blends where x is the mole percent of sulfonation.At x = 0.2%, the blends are fully miscible at 150°C to 190°C, while at x = 2.6% the system fully immiscible at the same temperatures. Intermediate levels of sulfonation (0.7, 1.0 and 1.2%) are partially miscible and exhibit an upper critical solution temperature (UCST). This behavior is attributed to the dilution of repulsive intra-molecular interaction between the ionic and non-ionic groups in the copolymer due to favorable interactions with the non-ionic group of the homopolymer PS. Estimates using the Flory-Huggins and the copolymer effect theories found a large ( 20) positive monomer-monomer interaction parameter between styrene and styrene sulfonate. This large interaction parameter might drive phase separation within a compositionally disperse random copolymers sample.

  6. STUDY ON THE MISCIBILITY OF DYNAMICALLY VULCANIZED EPDM/PP BLEND BY POSITRON ANNIHILATION SPECTROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Xue-liang Jiang; Shi-yuan Cheng; Yi-qun Dai; Shao-jie Wang; Bo Wang

    2000-01-01

    Positron annihilation spectroscopy (PAS) was utilized to investigate the relationship between the free-volume hole properties and miscibility of dynamically vulcanized EPDM/PP blend. The results showed that the noncrystalline region of PP and EPDM in the blend was partially miscible and the miscibility of the blend became worse when the weight percent of EPDM was <50%. This was also demonstrated by DMTA and mechanical properties of the blends with various compositions.

  7. An optical criterion to obtain miscible mixed crystals in alkali halides

    OpenAIRE

    2008-01-01

    This work gives a novel criterion to predict the formation of alkali halide solid solutions and discusses some results obtained in the development of ternary and quaternary miscible crystalline dielectric mixtures of alkali halides. These mixtures are miscible in any concentration of their components. The miscibility of these mixed crystals is quite related to the F center through the behavior observed in the spectral position of the optical absorption F band as a function of the lattice cons...

  8. GAP Analysis Program (GAP)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas GAP Analysis Land Cover database depicts 43 land cover classes for the state of Kansas. The database was generated using a two-stage hybrid classification...

  9. Concentration-dependent diffusion instability in reactive miscible fluids

    Science.gov (United States)

    Bratsun, Dmitry; Kostarev, Konstantin; Mizev, Aleksey; Mosheva, Elena

    2015-07-01

    We report on chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with frontal acid-base neutralization can give rise to the formation of a local unstable zone low in density, resulting in a perfectly regular cell-type convective pattern. The described effect gives an example of yet another powerful mechanism which allows the reaction-diffusion processes to govern the flow of reacting fluids under gravity conditions.

  10. Calculation of minimum miscibility pressure using fast slimtube simulation

    DEFF Research Database (Denmark)

    Yan, Wei; Michelsen, Michael Locht; Stenby, Erling Halfdan

    2012-01-01

    Minimum misciblility pressure (MMP) is a critical parameter in designing a miscible gas injection process. It is expected that 100% displacement efficiency on the microscopic scale can be achieved provided the injection pressure is above MMP. Two approaches are usually employed for equation of st...... is poroposed to reduce the number of slimtube simulations needed. In addition, it is also discussed how to parallelize slimtube simulations for modem computers with multiple CPU cores to further chop the computation time. Copyright 2012, Society of Petroleum Engineers....

  11. Concentration-Dependent Diffusion Instability in Reactive Miscible Fluids

    CERN Document Server

    Bratsun, Dmitry; Mizev, Alexey; Mosheva, Elena

    2015-01-01

    We report new chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with the frontal acid-base neutralization can give rise to formation of the local unstable zone low in density resulting in a perfectly regular cell-type convective pattern. The described effect gives an example of yet another powerful mechanism which allows the reaction-diffusion processes to govern the flow of reacting fluids under gravity condition.

  12. Investigation of Polymer-Surfactant and Polymer-Drug-Surfactant Miscibility for Solid Dispersion.

    Science.gov (United States)

    Gumaste, Suhas G; Gupta, Simerdeep Singh; Serajuddin, Abu T M

    2016-09-01

    In a solid dispersion (SD), the drug is generally dispersed either molecularly or in the amorphous state in polymeric carriers, and the addition of a surfactant is often important to ensure drug release from such a system. The objective of this investigation was to screen systematically polymer-surfactant and polymer-drug-surfactant miscibility by using the film casting method. Miscibility of the crystalline solid surfactant, poloxamer 188, with two commonly used amorphous polymeric carriers, Soluplus® and HPMCAS, was first studied. Then, polymer-drug-surfactant miscibility was determined using itraconazole as the model drug, and ternary phase diagrams were constructed. The casted films were examined by DSC, PXRD and polarized light microscopy for any crystallization or phase separation of surfactant, drug or both in freshly prepared films and after exposure to 40°C/75% RH for 7, 14, and 30 days. The miscibility of poloxamer 188 with Soluplus® was <10% w/w, while its miscibility with HPMCAS was at least 30% w/w. Although itraconazole by itself was miscible with Soluplus® up to 40% w/w, the presence of poloxamer drastically reduced its miscibility to <10%. In contrast, poloxamer 188 had minimal impact on HPMCAS-itraconazole miscibility. For example, the phase diagram showed amorphous miscibility of HPMCAS, itraconazole, and poloxamer 188 at 54, 23, and 23% w/w, respectively, even after exposure to 40°C/75% RH for 1 month. Thus, a relatively simple and practical method of screening miscibility of different components and ultimately physical stability of SD is provided. The results also identify the HPMCAS-poloxamer 188 mixture as an optimal surface-active carrier system for SD.

  13. Interacting binaries

    CERN Document Server

    Shore, S N; van den Heuvel, EPJ

    1994-01-01

    This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

  14. Molecular Dynamics Simulation of Miscibility in Several Polymer Blends

    CERN Document Server

    Ahmadi, Amirhossein

    2009-01-01

    The miscibility in several polymer blend mixtures (polymethylmethacrylate/polystyrene, (1,4-cis) polyisoprene/polystyrene, and polymethylmethacrylate/polyoxyethylene) has been investigated using Molecular Dynamics simulations for atomistic representations of the polymer chains. The trajectories obtained from simulation boxes representing the mixtures have been analyzed in terms of the collective scattering structure function. The Flory-Huggins parameter is determined from fits of the simulation results for this function to the random phase approximation expression. The numerical values of this parameter and its variation with temperature obtained with this procedure show a general qualitative and quantitative agreement with existing experimental data for the different systems. These results together with those previously obtained for the polyvylmethylether/polystyrene blends with the same method are compared with data yielded by other computational simpler approaches.

  15. Miscible displacement fronts of shear thinning fluids inside rough fractures

    CERN Document Server

    Boschan, A; Ippolito, I; Chertcoff, R; Hulin, J P; Boschan, Alexandro; Auradou, Harold; Ippolito, Irene; Chertcoff, Ricardo; Hulin, Jean-Pierre

    2006-01-01

    The miscible displacement of a shear-thinning fluid by another of same rheological properties is studied experimentally in a transparent fracture by an optical technique imaging relative concentration distributions. The fracture walls have complementary self-affine geometries and are shifted laterally in the direction perpendicular to the mean flow velocity {\\bf U} : the flow field is strongly channelized and macro dispersion controls the front structure for P\\'{e}clet numbers above a few units. The global front width increases then linearly with time and reflects the velocity distribution between the different channels. In contrast, at the local scale, front spreading is similar to Taylor dispersion between plane parallel surfaces. Both dispersion mechanisms depend strongly on the fluid rheology which shifts from Newtonian to shear-thinning when the flow rate increases. In the latter domain, increasing the concentration enhances the global front width but reduces both Taylor dispersion (due to the flattening...

  16. Laminar flow of two miscible fluids in a simple network

    CERN Document Server

    Karst, Casey M; Geddes, John B

    2012-01-01

    When a fluid comprised of multiple phases or constituents flows through a network, non-linear phenomena such as multiple stable equilibrium states and spontaneous oscillations can occur. Such behavior has been observed or predicted in a number of networks including the flow of blood through the microcirculation, the flow of picoliter droplets through microfluidic devices, the flow of magma through lava tubes, and two-phase flow in refrigeration systems. While the existence of non-linear phenomena in a network with many inter-connections containing fluids with complex rheology may seem unsurprising, this paper demonstrates that even simple networks containing Newtonian fluids in laminar flow can demonstrate multiple equilibria. The paper describes a theoretical and experimental investigation of the laminar flow of two miscible Newtonian fluids of different density and viscosity through a simple network. The fluids stratify due to gravity and remain as nearly distinct phases with some mixing occurring only by d...

  17. The Effect of Counterions on the Blend Miscibility of Polystyrene with Sulfonated Polystyrene Ionomers

    Science.gov (United States)

    Zhou, Nancy C.; Burghardt, Wesley R.; Composto, Russell J.; Winey, Karen I.

    2006-03-01

    Our previous study probed the miscibility of polystyrene (PS) and sulfonated polystyrene (P(S-SSx)) of differing sulfonation levels (x) and found a narrow window of miscibility. Specifically, the PS:P(S-SSx) blend system becomes completely immiscible at unexpectedly low sulfonation level, x = 2.7 mol% . Here we extend the study of blend miscibility of PS with P(S-SS0.007) to include materials neutralized with sodium, barium and zinc cations. These ionomer blends exhibit an upper critical solution temperature (UCST) behavior with an increase in critical temperature as compared to the blend with unneutralized P(S-SS0.007). Forward recoil spectrometry (FRES) results indicate that Zn^++ and Ba^++ neutralized ionomers are less miscible than Na^+ when fully neutralized, while the blend miscibility for Na^+ and Zn^++ neutralized ionomers behave similarly when partially neutralized. Rheological studies are underway to compliment the blend miscibility studies. These miscibility information gained from PS/P(S-SSx) ionomers blends will serve as a foundation for future ionomer morphology studies.

  18. Theoretical and experimental investigation of drug-polymer interaction and miscibility and its impact on drug supersaturation in aqueous medium.

    Science.gov (United States)

    Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

    2016-10-01

    Amorphous solid dispersions (ASDs) have the potential to offer higher apparent solubility and bioavailability of BCS class II drugs. Knowledge of the solid state drug-polymer solubility/miscibility and their mutual interaction are fundamental requirements for the effective design and development of such systems. To this end, we have carried out a comprehensive investigation of various ASD systems of dipyridamole and cinnarizine in polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) at different drug loadings. Theoretical and experimental examinations (by implementing binary and ternary Flory-Huggins (F-H) theory) related to drug-polymer interaction/miscibility including solubility parameter approach, melting point depression method, phase diagram, drug-polymer interaction in the presence of moisture and the effect of drug loading on interaction parameter were performed. The information obtained from this study was used to predict the stability of ASDs at different drug loadings and under different thermal and moisture conditions. Thermal and moisture sorption analysis not only provided the composition-dependent interaction parameter but also predicted the composition dependent miscibility. DPM-PVP, DPM-PAA and CNZ-PAA systems have shown molecular level mixing over the complete range of drug loading. For CNZ-PVP, the presence of a single Tg at lower drug loadings (10, 20 and 35%w/w) indicates the formation of solid solution. However, drug recrystallization was observed for samples with higher drug weight fractions (50 and 65%w/w). Finally, the role of polymer in maintaining drug supersaturation has also been explored. It has been found that drug-polymer combinations capable of hydrogen-bonding in the solution state (DPM-PVP, DPM-PAA and CNZ-PAA) are more effective in preventing drug crystallization compared to the drug-polymer systems without such interaction (CNZ-PVP). The DPM-PAA system outperformed all other ASDs in various stability conditions (dry-state, in

  19. Dynamical mass transfer in cataclysmic binaries

    Science.gov (United States)

    Melia, Fulvio; Lamb, D. Q.

    1987-01-01

    When a binary comes into contact and mass transfer begins, orbital angular momentum is stored in the accretion disk until the disk couples tidally to the binary system. Taam and McDermott (1987) have suggested that this leads to unstable dynamical mass transfer in many cataclysmic variables in which mass transfer would otherwise be stable, and that it explains the gap between 2 and 3 h in the orbital period distribution of these systems. Here the consequences of this hypothesis for the evolution of cataclysmic binaries are explored. It is found that systems coming into contact longward of the period gap undergo one or more episodes of dynamical mass transfer.

  20. MISCIBILITY, SOLUBILITY, AND VISCOSITY MEASUREMENTS FOR R-236EA WITH POTENTIAL LUBRICANTS

    Science.gov (United States)

    The report gives results of miscibility, solubility, and viscosity measurements of refrigerant R-236ea with three potential lubricants. (NOTE: The data were needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The lubricants...

  1. Influence of Miscibility of Protein-Sugar Lyophilizates on Their Storage Stability.

    Science.gov (United States)

    Mensink, Maarten A; Nethercott, Matthew J; Hinrichs, Wouter L J; van der Voort Maarschalk, Kees; Frijlink, Henderik W; Munson, Eric J; Pikal, Michael J

    2016-09-01

    For sugars to act as successful stabilizers of proteins during lyophilization and subsequent storage, they need to have several characteristics. One of them is that they need to be able to form interactions with the protein and for that miscibility is essential. To evaluate the influence of protein-sugar miscibility on protein storage stability, model protein IgG was lyophilized in the presence of various sugars of different molecular weight. By comparing solid-state nuclear magnetic resonance spectroscopy relaxation times of both protein and sugar on two different timescales, i.e., (1)H T1 and (1)H T1ρ, miscibility of the two components was established on a 2-5- and a 20-50-nm length scale, respectively, and related to protein storage stability. Smaller sugars showed better miscibility with IgG, and the tendency of IgG to aggregate during storage was lower for smaller sugars. The largest sugar performed worst and was phase separated on both length scales. Additionally, shorter protein (1)H T1 relaxation times correlated with higher aggregation rates during storage. The enzyme-linked immunosorbent assay (ELISA) assay showed overlapping effects of aggregation and chemical degradation and did not correspond as well with the miscibility. Because of the small scale at which miscibility was determined (2-5 nm) and the size of the protein domains (∼2.5 × 2.5 × 5 nm), the miscibility data give an indirect measure of interaction between protein and sugar. This reduced interaction could be the result of steric hindrance, providing a possible explanation as to why smaller sugars show better miscibility and storage stability with the protein.

  2. Phase-field modelling of a miscible system in spinning droplet tensiometer.

    Science.gov (United States)

    Vorobev, Anatoliy; Boghi, Andrea

    2016-11-15

    The spinning drop tensiometry is used for measurements of surface tension coefficients, especially, when interfaces are characterised by low and ultra-low interfacial stresses. A droplet of lighter liquid is introduced into a rotating capillary that was initially saturated with another heavier liquid. The tube is subject to axial rotation that results in droplet's elongation along the tube's axis. The equilibrium shape of the droplet is used to determine the surface tension coefficient. In this work, the evolution of a slowly miscible droplet introduced into a spinning capillary is investigated. This technique is frequently employed for studies of the dynamics of miscible systems, even despite the fact that a strict equilibrium is never achieved in a mixture of fully miscible liquids. The numerical modelling of a miscible droplet is fulfilled on the basis of the phase-field (Cahn-Hilliard) approach. The numerical results are compared against the experimental data pursuing two objectives: (i) to verify the use of the phase-field approach as a consistent physics-based approach capable of accurate tracking of the short- and long-term evolution of miscible systems, and (ii) to estimate the values of the phenomenological parameters introduced within the phase-field approach, so making this approach a practical tool for modelling of thermohydrodynamic changes in miscible systems within various configurations.

  3. Respiratory exposure to components of water-miscible metalworking fluids.

    Science.gov (United States)

    Suuronen, Katri; Henriks-Eckerman, Maj-Len; Riala, Riitta; Tuomi, Timo

    2008-10-01

    Water-miscible metalworking fluids (MWFs) are capable of causing respiratory symptoms and diseases. Recently, much emphasis has been put on developing new methods for assessing respiratory exposure to MWF emulsions. The air concentrations of ingredients and contaminants of MWF and inhalable dust were measured in 10 metal workshops in southern Finland. Oil mist was determined by infra red spectroscopy analysis after tetrachloroethylene extraction from the filter. Aldehydes were collected on Sep-Pak chemosorbents and analysed by liquid chromatography. Volatile organic compounds (VOCs) were collected on Tenax adsorbents and analysed by gas chromatography with mass spectrometric detection after thermal desorption. Endotoxins were collected on glass fibre filter and analysed by enzyme-based spectrophotometry, and viable microbes were collected on polycarbonate filter and cultured. Inhalable dust was collected on cellulose acetate filter and quantified gravimetrically. Associations between the different exposures were calculated with Spearman's correlations. The mean concentration of oil mist was 0.14 (range aliphatic hydrocarbons. Several potential sensitizing chemicals such as terpenes were found in small quantities. The concentration of microbial contaminants was low. All the measured air concentrations were below the Finnish occupational exposure limits. The exposure in machine shops was quantitatively dominated by volatile compounds. Additional measurements of MWF components such as aldehydes, alkanolamines and VOCs are needed to get more information on the chemical composition of workshops' air. New air cleaning methods should be introduced, as oil mist separators are insufficient to clean the air of small molecular impurities.

  4. Alcohol drops on miscible liquid: mixing or spreading?

    Science.gov (United States)

    Kim, Hyoungsoo; Muller, Koen; Shardt, Orest; Afkhami, Shahriar; Stone, Howard

    2016-11-01

    We studied how a sessile drop of alcohol behaves when placed on a fully miscible liquid. The dynamics of the subsequent mixing and spreading were captured by using a high-speed camera and investigated by varying parameters (e.g., surface tension, density, and viscosity). We observed that a deposited alcohol drop on a liquid bath remains as a floating lens shape, the alcohol liquid leaks out along the rim of the droplet, and it spreads axi-symmetrically along the bottom liquid interface. To visualize spreading and mixing features, we used time-resolved Particle Tacking Velocimetry and a Schlieren method. We observed a localized mixing flow at the rim of the floating droplet where the maximum flow speed is obtained, driven by a solutal Marangoni effect. Underneath the interface of the bath liquid, a viscous boundary layer develops while the alcohol liquid spreads along the radial direction. We also observed a finite quasi-steady interfacial flow velocity regime after the alcohol droplet touched the bottom liquid surface. In this regime, the flow speed linearly increases inside the floating lens, and outside the lens the flow speed decays along the r-direction with a power-law slope, Ur r - 1 / 2 . Physical arguments to support the observations will be discussed.

  5. Silk fibroin and sodium alginate blend: Miscibility and physical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Agostini de Moraes, Mariana; Silva, Mariana Ferreira; Weska, Raquel Farias; Beppu, Marisa Masumi, E-mail: beppu@feq.unicamp.br

    2014-07-01

    Films of silk fibroin (SF) and sodium alginate (SA) blends were prepared by solution casting technique. The miscibility of SF and SA in those blends was evaluated and scanning electron microscopy (SEM) revealed that SF/SA 25/75 wt.% blends underwent microscopic phase separation, resulting in globular structures composed mainly of SF. X-ray diffraction indicated the amorphous nature of these blends, even after a treatment with ethanol that turned them insoluble in water. Thermal analyses of blends showed the peaks of degradation of pristine SF and SA shifted to intermediate temperatures. Water vapor permeability, swelling capacity and tensile strength of SF films could be enhanced by blending with SA. Cell viability remained between 90 and 100%, as indicated by in vitro cytotoxicity test. The SF/SA blend with self-assembled SF globules can be used to modulate structural and mechanical properties of the final material and may be used in designing high performance wound dressing. - Highlights: • Blend films of fibroin and alginate were prepared with microscopic phase separation; • Self-assembled globular microdomains were mainly composed by fibroin; • It was possible to obtain a film with better mechanical and physical properties; • Blend films of fibroin and alginate represent a novel material in biomaterials field.

  6. MISCIBILITY, CRYSTALLIZATION AND MECHANICAL PROPERTIES OF PPC/PBS BLENDS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, melt blends of poly(propylene carbonate) (PPC) with poly(butylene succinate) (PBS) were characterized by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), tensile testing, wide-angle X-ray diffraction (WAXD), polarized optical microscopy and thermogravimetric analysis (TGA). The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11 K comparing with that of pure PPC. The presence of 10% PBS was partially miscible with PPC. The 90/10 PPC/PBS blend had better impact and tensile strength than those of the other PPC/PBS blends. The glass transition temperature of PPC in the 80/20, 70/30, and 60/40 PPC/PBS blends was improved by about 4.9 K, 4.2 K, and 13 K comparing with that of pure PPC, respectively; which indicated the immiscibility between PPC and PBS. The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased. The matrix of PPC hindered the crystallization process of PBS. While the content of PBS was above 20%, significant crystallization-induced phase separation was observed by polarized optical microscopy.It was found from the WAXD analysis that the crystal structure of PBS did not change, and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.

  7. Miscibility of Itraconazole-Hydroxypropyl Methylcellulose Blends: Insights with High Resolution Analytical Methodologies.

    Science.gov (United States)

    Purohit, Hitesh S; Taylor, Lynne S

    2015-12-07

    Drug-polymer miscibility is considered to be a prerequisite to achieve an optimally performing amorphous solid dispersion (ASD). Unfortunately, it can be challenging to evaluate drug-polymer miscibility experimentally. The aim of this study was to investigate the miscibility of ASDs of itraconazole (ITZ) and hydroxypropyl methylcellulose (HPMC) using a variety of analytical approaches. The phase behavior of ITZ-HPMC films prepared by solvent evaporation was studied before and after heating. Conventional methodology for miscibility determination, that is, differential scanning calorimetry (DSC), was used in conjunction with emerging analytical techniques, such as fluorescence spectroscopy, fluorescence imaging, and atomic force microscopy coupled with nanoscale infrared spectroscopy and nanothermal analysis (AFM-nanoIR-nanoTA). DSC results showed a single glass transition event for systems with 10% to 50% drug loading, suggesting that the ASDs were miscible, whereas phase separation was observed for all of the films based on the other techniques. The AFM-coupled techniques indicated that the phase separation occurred at the submicron scale. When the films were heated, it was observed that the ASD components underwent mixing. The results provide new insights into the phase behavior of itraconazole-HPMC dispersions and suggest that the emerging analytical techniques discussed herein are promising for the characterization of miscibility and microstructure in drug-polymer systems. The observed differences in the phase behavior in films prepared by solvent evaporation before and after heating also have implications for processing routes and suggest that spray drying/solvent evaporation and hot melt extrusion/melt mixing can result in ASDs with varying extent of miscibility between the drug and the polymer.

  8. Shell plans big COD/sub 2/U miscible drive

    Energy Technology Data Exchange (ETDEWEB)

    1966-04-18

    Shell Oil Co. is seeking approval from the Texas Railroad Commission for the first field test using COD2U as a miscible slug. The test would take place in the Crossett Field, Crane and Upton Counties, 5 miles West of McCamey. Plan calls for injecting a large slug of COD2U in the Devonian reservoir, and following this with water to maintain reservoir pressure and serve as a sweeping medium. If the method works as anticipated, Shell says it will recover 32.8 million bbl of 44$-gravity crude--or 63.8% of the oil originally in place. Residue gas in now being injected in the field's North Cross unit. Widespread application of the process, if it works as hoped, seems unlikely because of the difficulty and cost of transporting COD2U where it is needed. However, ample supplies of COD2U are available in West Texas. There are at least 3 sources of COD2U in the vicinity. Norhtern Natural Gas Co. is venting some 20 MMcfd at is gas processing plant at Puckett field in Pecos County. Not far away is Hunt Oil Co.'s 57 Elsinore Ranch well, a dry hole that tested COD2U at the rate of 19 MMcfd. The most likely source of COD2U for Shell's proposed test is El Paso Natural Gas Co.'s processing plant at Brown-Basset Field in Terrell County, where gas is now being vented to the atmosphere at the rate of 40 MMscfd.

  9. Spinodal decomposition of chemically reactive binary mixtures

    Science.gov (United States)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  10. Miscibility of eudragit/chitosan polymer blend in water determined by physical property measurements.

    Science.gov (United States)

    Haque, Sk Ershadul; Sheela, A

    2013-01-30

    The interest in the preparation and application of polymeric blends is growing since they can exhibit properties of great industrial interest. The current study focuses on the preparation of polymeric blends of varying compositions of eudragit and chitosan and their miscibility studies. The preparation was carried out by using ethanol and 1% acetic acid in water. FT-IR spectra reveal the possibilities of chemical interactions between eudragit/chitosan. The miscibility of polymeric blend at different composition has been investigated by viscosity, ultrasonic velocity, density, refractive index and adiabatic compressibility values measured at two different temperatures 30 °C and 40 °C. The interaction parameters ΔB, μ and α, were determined from viscosity data. From the values observed, it is found that the blend is miscible in all compositions at 30 °C whereas at 40 °C, it seems to be immiscible in certain compositions. It is found that the blend is miscible, when the chitosan concentration is more than 70% (v/v) at both the temperatures and also observed that variation of temperature has no effect on the miscibility of eudragit/chitosan blend.

  11. Effect of PEO molecular weight on the miscibility and dynamics in epoxy/PEO blends.

    Science.gov (United States)

    Lu, Shoudong; Zhang, Rongchun; Wang, Xiaoliang; Sun, Pingchuan; Lv, Weifeng; Liu, Qingjie; Jia, Ninghong

    2015-11-01

    In this work, the effect of poly(ethylene oxide) (PEO) molecular weight in blends of epoxy (ER) and PEO on the miscibility, inter-chain weak interactions and local dynamics were systematically investigated by multi-frequency temperature modulation DSC and solid-state NMR techniques. We found that the molecular weight (M(w)) of PEO was a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interactions between PEO and ER. A critical PEO molecular weight (M(crit)) around 4.5k was found. PEO was well miscible with ER when the molecular weight was below M(crit), where the chain motion of PEO was restricted due to strong inter-chain hydrogen bonding interactions. However, for the blends with high molecular weight PEO (M(w) > M(crit)), the miscibility between PEO and ER was poor, and most of PEO chains were considerably mobile. Finally, polarization inversion spin exchange at magic angle (PISEMA) solid-state NMR experiment further revealed the different mobility of the PEO in ER/PEO blends with different molecular weight of PEO at molecular level. Based on the DSC and NMR results, a tentative model was proposed to illustrate the miscibility in ER/PEO blends.

  12. Calcium Carbonate Crystal Growth in Porous Media, in the presence of Water Miscible and Non-Miscible Organic Fluids

    Science.gov (United States)

    Jaho, Sofia; Sygouni, Varvara; Paraskeva, Christakis A.

    2015-04-01

    The deposition of sparingly soluble salts (scaling) within porous media is a major problem encountered in many industrial and environmental applications. In the oil industry scaling causes severe operational malfunctions and, therefore, increasing the total operating and maintenance cost [1]. The most common types of sparingly soluble salts located in oil fields include carbonate and sulfate salts of calcium, strondium and barium[1,2]. Multiple phase flow and tubing surface properties are some of the factors affecting scale formation [3]. The main purpose of the present work was the investigation of the precipitation mechanisms of calcium carbonate (CaCO3) through in situ mixing of two soluble salt solutions in a flow granular medium, in the presence of water miscible organic fluid (ethylene glycol) or non-miscible organic fluid (n-dodecane). All series of experiments were carried out in a two dimensional porous medium made of Plexiglas. For all solutions used in the experiments, the contact angles with the surface of the porous medium and the interfacial tensions were measured. During the experiments, the calcium carbonate crystal growth was continuously monitored and recorded through an optical microscope equipped with a digital programmed video camera. The snap-shots were taken within specific time intervals and their detailed procession gave information concerning the crystal growth rate and kinetics. The pH of the effluent was measured and fluids samples were collected for calcium analysis using Atomic Absorption Spectroscopy (AAS). In all experiments effluent calcium concentration decreased as a function of time, suggesting that CaCO3 precipitation took place inside the porous medium. Crystals of the precipitated salt were identified using Infrared Spectroscopy (IR) and the morphology of the crystals was examined using Scanning Electron Microscopy (SEM). The induction time for precipitation of CaCO3 crystals in the presence of n-dodecane was significantly

  13. Knowledge Gaps

    DEFF Research Database (Denmark)

    Lyles, Marjorie; Pedersen, Torben; Petersen, Bent

    2003-01-01

    , assimilating, and utilizing knowledge - are crucial determinants ofknowledge gap elimination. In contrast, the two factors deemed essential in traditionalinternationalization process theory - elapsed time of operations and experientiallearning - are found to have no or limited effect.Key words......: Internationalization, knowledge gap, absorptive capacity, learning box....

  14. Shift in membrane miscibility transition temperature upon addition of short-chain alcohols

    Science.gov (United States)

    Schick, M.

    2016-12-01

    I consider the effect of a small concentration of a molecule, such as a short-chain alcohol, on the miscibility transition temperature of a giant plasma membrane vesicle. For concentrations sufficiently small such that the system can be treated as a dilute solution, the change in transition temperature is known to depend upon the extent of the molecule's partition into the coexisting liquid-disordered and liquid-ordered phases. Preferential partitioning into the former decreases the miscibility temperature, while preferential partitioning into the latter causes an increase. The analysis, combined with calculated values of the partition coefficient of saturated chains, illuminates the results of recent experiments on the change in miscibility transition temperatures with changing alcohol chain length, and makes several testable predictions.

  15. The Effects of Branching and Deuterium Labeling on Polymer Blend Miscibility

    Science.gov (United States)

    Defelice, Jeffrey; Higgins, Julia; Lipson, Jane

    Local structural or chemical changes made to one component of a polymer blend can have a significant impact on miscibility. In this talk we will focus on several blends involving linear and 4-arm star polystyrene (PS), both hydrogenous and deuterated, and poly(vinylmethylether) (PVME). We consider the effect of the structural change on the miscibility of PS/PVME, then turn to the added effect of deuterium labeling, both on this blend and for isotopic PS mixtures. Using our Locally Correlated Lattice (LCL) model we are able to identify trends in the physical properties of pure components, such as: free volume, thermal expansion coefficient, and cohesive energy density. We find that branching and labeling, both independently and cumulatively, affect pure component properties. Our ability to correlate structural and chemical changes with trends in physical properties leads to predictions about the compatibility of pure components, and thus their blend miscibility. The authors gratefully acknowledge support from NSF DMR-1403757 and GAANN.

  16. Influence of viscosity contrast on buoyantly unstable miscible fluids in porous media

    CERN Document Server

    Pramanik, Satyajit; Mishra, Manoranjan

    2015-01-01

    The influence of viscosity contrast on buoyantly unstable miscible fluids in a porous medium is investigated through a linear stability analysis (LSA) as well as direct numerical simulations (DNS). The linear stability method implemented in this paper is based on an initial value approach, which helps to capture the onset of instability more accurately than the quasi-steady state analysis. In the absence of displacement, we show that viscosity contrast delays the onset of instability in buoyantly unstable miscible fluids. Further, it is observed that suitably choosing the viscosity contrast and injection velocity a gravitationally unstable miscible interface can be stabilized completely. Through LSA we draw a phase diagram, which shows three distinct stability regions in a parameter space spanned by the displacement velocity and the viscosity contrast. DNS are performed corresponding to parameters from each regime and the results obtained are in accordance with the linear stability results. Moreover, the conv...

  17. Data mining of solubility parameters for computational prediction of drug-excipient miscibility.

    Science.gov (United States)

    Alhalaweh, Amjad; Alzghoul, Ahmad; Kaialy, Waseem

    2014-07-01

    Abstract Computational data mining is of interest in the pharmaceutical arena for the analysis of massive amounts of data and to assist in the management and utilization of the data. In this study, a data mining approach was used to predict the miscibility of a drug and several excipients, using Hansen solubility parameters (HSPs) as the data set. The K-means clustering algorithm was applied to predict the miscibility of indomethacin with a set of more than 30 compounds based on their partial solubility parameters [dispersion forces (δd), polar forces (δp) and hydrogen bonding (δh)]. The miscibility of the compounds was determined experimentally, using differential scanning calorimetry (DSC), in a separate study. The results of the K-means algorithm and DSC were compared to evaluate the K-means clustering prediction performance using the HSPs three-dimensional parameters, the two-dimensional parameters such as volume-dependent solubility (δv) and hydrogen bonding (δh) and selected single (one-dimensional) parameters. Using HSPs, the prediction of miscibility by the K-means algorithm correlated well with the DSC results, with an overall accuracy of 94%. The prediction accuracy was the same (94%) when the two-dimensional parameters or the hydrogen-bonding (one-dimensional) parameter were used. The hydrogen-bonding parameter was thus a determining factor in predicting miscibility in such set of compounds, whereas the dispersive and polar parameters had only a weak correlation. The results show that data mining approach is a valuable tool for predicting drug-excipient miscibility because it is easy to use, is time and cost-effective, and is material sparing.

  18. STUDIES ON MISCIBILITY OF POLY (ε-CAPROLACTONE) AND ALIPHATIC POLYCARBONATE BLENDS AND DETERMINATION OF THEIR INTERACTION PARAMETER

    Institute of Scientific and Technical Information of China (English)

    CHEN Li; HUANG Yuhui; SONG Mo; CONG Guangmin

    1992-01-01

    In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (AP C) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.

  19. Influence of the degree of hydrolysis of poly(styrene-alt-maleic anhydride) on miscibility with poly(vinyl acetate)

    NARCIS (Netherlands)

    Bosma, M.; Vorenkamp, E.J.; Brinke, G. ten; Challa, G.

    1988-01-01

    The influence of the hydrolysis of anhydride groups in poly(styrene-alt-maleic anhydride) (PSMA) on its miscibility with poly(vinyl acetate) (PVAc) is investigated. The cloudpoint curves of these blends are determined as a function of the degree of hydrolysis. The miscibility is shown to improve wit

  20. Miscibility Development Computation in Enhanced Oil Recovery by Flare Gas Flooding

    OpenAIRE

    Tjokorde Walmiki Samadhi; Utjok W.R. Siagian; Angga P. Budiono

    2012-01-01

    The use of flare gas as injection gas in miscible gas flooding enhanced oil recovery (MGF-EOR) presents a potential synergy between oil production improvement and greenhouse gases emission mitigation. This work is a preliminary evaluation of the feasibility of miscible flare gas injection based on phase behavior computations of a model oil (43%n-C5H12 : 57%n-C16H34) and a model flare gas (91%CH4 : 9%C2H6). The computations employed the multiple mixing-cell model with Peng-Robinson and PC-SAFT...

  1. Miscibility study of hexanoyl chitosan in blend with epoxidized natural rubber by viscometric analysis

    Science.gov (United States)

    Jamal, Asheila; Chan, C. H.; Muhammad, F. H.; Winie, Tan

    2015-08-01

    Miscibility of blends of hexanoyl chitosan and epoxidized natural rubber with 25 mol% epoxidation level (ENR25) was investigated by dilute solution viscometry (DSV). Experimental results obey the Huggins' equation in the concentration range under investigation. Intrinsic viscosities are found to vary linearly with blend composition. The difference between experimental and ideal Huggins coefficients, κ =K12-√{K1ṡK2 } is proposed to evaluate the miscibility behavior of the blends. Negative deviations from the ideal behavior indicated immiscibility between hexanoyl chitosan and ENR25.

  2. Thermodynamics and Phase Behavior of Miscible Polymer Blends in the Presence of Supercritical Carbon Dioxide

    Science.gov (United States)

    Young, Nicholas Philip

    The design of environmentally-benign polymer processing techniques is an area of growing interest, motivated by the desire to reduce the emission of volatile organic compounds. Recently, supercritical carbon dioxide (scCO 2) has gained traction as a viable candidate to process polymers both as a solvent and diluent. The focus of this work was to elucidate the nature of the interactions between scCO2 and polymers in order to provide rational insight into the molecular interactions which result in the unexpected mixing thermodynamics in one such system. The work also provides insight into the nature of pairwise thermodynamic interactions in multicomponent polymer-polymer-diluent blends, and the effect of these interactions on the phase behavior of the mixture. In order to quantify the strength of interactions in the multicomponent system, the binary mixtures were characterized individually in addition to the ternary blend. Quantitative analysis of was made tractable through the use of a model miscible polymer blend containing styrene-acrylonitrile copolymer (SAN) and poly(methyl methacrylate) (dPMMA), a mixture which has been considered for a variety of practical applications. In the case of both individual polymers, scCO2 is known to behave as a diluent, wherein the extent of polymer swelling depends on both temperature and pressure. The solubility of scCO 2 in each polymer as a function of temperature and pressure was characterized elsewhere. The SAN-dPMMA blend clearly exhibited lower critical solution temperature behavior, forming homogeneous mixtures at low temperatures and phase separating at elevated temperature. These measurements allowed the determination of the Flory-Huggins interaction parameter chi23 for SAN (species 2) and dPMMA (species 3) as a function of temperature at ambient pressure, in the absence of scCO2 (species 1). Characterization of the phase behavior of the multicomponent (ternary) mixture was also carried out by SANS. An in situ SANS

  3. Mythic gaps

    Directory of Open Access Journals (Sweden)

    William Hansen

    2014-11-01

    Full Text Available Different kinds of omissions sometimes occur, or are perceived to occur, in traditional narratives and in tradition-inspired literature. A familiar instance is when a narrator realizes that he or she does not fully remember the story that he or she has begun to tell, and so leaves out part of it, which for listeners may possibly result in an unintelligible narrative. But many instances of narrative gap are not so obvious. From straightforward, objective gaps one can distinguish less-obvious subjective gaps: in many cases narrators do not leave out anything crucial or truly relevant from their exposition, and yet readers perceive gaps and take steps to fill them. The present paper considers four examples of subjective gaps drawn from ancient Greek literature (the Pandora myth, ancient Roman literature (the Pygmalion legend, ancient Hebrew literature (the Joseph legend, and early Christian literature (the Jesus legend. I consider the quite varied ways in which interpreters expand the inherited texts of these stories, such as by devising names, manufacturing motives, creating backstories, and in general filling in biographical ellipses. Finally, I suggest an explanation for the phenomenon of subjective gaps, arguing that, despite their variety, they have a single cause.

  4. Binary effectivity rules

    DEFF Research Database (Denmark)

    Keiding, Hans; Peleg, Bezalel

    2006-01-01

    is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...... effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann-Morgenstern solutions play an important role in this characterization...

  5. GAP Analysis Program (GAP) Raster

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas GAP Land Cover database depicts 43 land cover classes for the state of Kansas. The database was generated using a two-stage hybrid classification of...

  6. Exploratory studies on the carboxymethylation of cassava starch in water-miscible organic media

    NARCIS (Netherlands)

    Yao, J; Chen, WR; Manurung, RM; Ganzeveld, KJ; Heeres, HJ; Manurung, Robbert M.; Chen, Wen-ren

    2004-01-01

    The carboxymethylation of cassava starch using sodium monochloroacetate (SMCA) as an etherification agent was investigated. Mixtures of water and water-miscible organic liquids were selected as carboxymethylation reaction medium to obtain a high degree of substitution (DS) without changing the granu

  7. The impact of miscibility on organic solar cell performance and stability

    Science.gov (United States)

    Collins, Brian A.; Tumbleston, John R.; Bartelt, Jon A.; McGehee, Michael D.; McNeill, Christopher R.; Ade, Harald

    2013-03-01

    The recent demonstration of molecular miscibility/solubility between polymers and fullerenes has revealed a much more complex picture of nanostructure, charge dynamics, and device stability - aspects that are all entangled. Here we show that miscibility is important in several ways that depends on the particular material blend. For example, recent absolute measurements on domain size and composition have revealed nanostructure in PTB7:PC71BM blends that is controlled by miscibility and that well-mixed regions likely hinder charge separation in this system. On the other hand, PBDTTPD:PC61BM blends rely on high levels of mixing for electron percolation. Such evidence leads to a complex interplay between charge separation, electron trapping, and percolation. Miscibility, a thermodynamic parameter, can, furthermore, determine the thermal stability of device active layers, which we show varies widely between materials systems. This suggests tailoring of the molecular interactions between donor and acceptor materials in solar cells may be the key to high-performing, highly stable and, therefore, economically viable organic electronics technologies.

  8. Dynamic Interactions between Matrix and Fracture in Miscible Solvent Flooding of Fractured Reservoirs

    NARCIS (Netherlands)

    Amerighasrodashti, A.; Farajzadeh, R.; Verlaan, M.; Suicmez, V.S.; Bruining, J.

    2013-01-01

    Miscible solvent injection has received increasing attention in recent years as an efficient method to improve oil recovery from fractured reservoirs. Due to the large permeability difference between fracture and matrix, the success of this method depends to large extent on the degree of enhancement

  9. Miscibility Development Computation in Enhanced Oil Recovery by Flare Gas Flooding

    Directory of Open Access Journals (Sweden)

    Tjokorde Walmiki Samadhi

    2012-11-01

    Full Text Available The use of flare gas as injection gas in miscible gas flooding enhanced oil recovery (MGF-EOR presents a potential synergy between oil production improvement and greenhouse gases emission mitigation. This work is a preliminary evaluation of the feasibility of miscible flare gas injection based on phase behavior computations of a model oil (43%n-C5H12 : 57%n-C16H34 and a model flare gas (91%CH4 : 9%C2H6. The computations employed the multiple mixing-cell model with Peng-Robinson and PC-SAFT equations of state, and compared the minimum miscibility pressure (MMP value in the cases of flare gas injection and CO2 injection. For CO2 injection, both equations of state produced MMP values close to the measured value of 10.55 MPa. Flare gas injection MMP values were predicted to be 3.6-4.5 times those of CO2 injection. This very high MMP implies high gas compression costs, and may compromise the integrity of the reservoir. Subsequent studies shall explore the gas-oil miscibility behavior of mixtures of flare gas with intermediate hydrocarbon gases and CO2, in order to identify a suitable approach for rendering flare gas feasible as an injection gas in MGF-EOR.

  10. The Consequence of Donor-acceptor Miscibility on Charge Transport and Photovoltaic Device Performance

    Science.gov (United States)

    Vakhshouri, Kiarash; Kozub, Derek; Wang, Chenchen; Salleo, Alberto; Gomez, Enrique

    2013-03-01

    Recent energy-filtered transmission electron microscopy studies revealed that amorphous mixed phases are ubiquitous within mesostructured polythiophene/fullerene mixtures. The role of mixing within nanophases on charge transport of organic semiconductor mixtures, however, is not fully understood. Through the combination of Flory-Huggins theory and energy-filtered transmission electron microscopy, we have estimated the miscibility limit of polythiophene/fullerene blends. We have also demonstrated the interplay between miscibility and percolation to describe field-effect mobilities as a measure of the conductive pathways present in a model organic semiconductor mixture (amorphous polythiophene/fullerene blends). Our studies reveal that the miscibility of the components strongly affects electron transport within amorphous blends. Immiscibility promotes efficient electron transport by promoting percolating pathways within organic semiconductor mixtures. However, strongly immiscible systems would readily phase separate into large domains, preventing efficient charge separation in organic photovoltaics. Consequently, an optimum degree of miscibility between donor/acceptor mixtures exists for the application of such mixtures to organic solar cells.

  11. Evaluation of miscible and immiscible CO2 injection in one of the Iranian oil fields

    Directory of Open Access Journals (Sweden)

    Aref Hashemi Fath

    2014-09-01

    Full Text Available Carbon dioxide (CO2 flooding is one of the most important methods for enhanced oil recovery (EOR because it not only increases oil recovery efficiency but also causes a reduction of greenhouse gas emissions. It is a very complex system, involving phase behavior that could increase the recovery of oil by means of swelling, evaporation and decreasing viscosity of the oil. In this study, a reservoir modeling approach was used to evaluate immiscible and miscible CO2 flooding in a fractured oil field. To reduce simulation time, we grouped fluid components into 10 pseudo-components. The 3-parameter, Peng–Robinson Equation of State (EOS was used to match PVT experimental data by using the PVTi software. A one-dimensional slim-tube model was defined using ECLIPSE 300 software to determine the minimum miscibility pressure (MMP for injection of CO2. We used FloGrid software for making a reservoir static model and the reservoir model was calibrated using manual and assisted history matching methods. Then various scenarios of natural depletion, immiscible and miscible CO2 injection have been simulated by ECLIPSE 300 software and then the simulation results of scenarios have been compared. Investigation of simulation results shows that the oil recovery factor in miscible CO2 injection scenario is more than other methods.

  12. MISCIBILITY, SOLUBILITY, VISCOSITY, AND DENSITY MEASUREMENTS FOR R-236FA WITH POTENTIAL LUBRICANTS

    Science.gov (United States)

    The report gives results of miscibility, solubility, viscosity, and density measurements for refrigerant R-236fa and two potential lubricants . (The data are needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The tested oi...

  13. MISCIBILITY, SOLUBILITY, VISCOSITY, AND DENSITY MEASUREMENTS FOR R-236EA WITH FOUR DIFFERENT EXXON LUBRICANTS

    Science.gov (United States)

    The report discusses miscibility, solubility, viscosity, and density data for the refrigerant hydrofluorocarbon (HFC)-236ea (or R-236ea) and four lubricants supplied by Exxon Corporation. Such data are needed to determine the suitability of refrigerant/lubricant combinations for ...

  14. Maximizing the Optical Band Gap in 2D Photonic Crystals

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Sigmund, Ole

    Topology optimization is used to find the 2D photonic crystal designs with the largest relative photonic band gaps. Starting points for the topology optimization are found with an exhaustive binary search on a low resolution grid.......Topology optimization is used to find the 2D photonic crystal designs with the largest relative photonic band gaps. Starting points for the topology optimization are found with an exhaustive binary search on a low resolution grid....

  15. Detecting phase separation of freeze-dried binary amorphous systems using pair-wise distribution function and multivariate data analysis

    DEFF Research Database (Denmark)

    Chieng, Norman; Trnka, Hjalte; Boetker, Johan;

    2013-01-01

    -PDF data using PCA provides a more clear 'miscible' or 'phase separated' interpretation through the distribution pattern of samples on a score plot presentation compared to residual plot method. In a phase separated system, samples were found to be evenly distributed around the theoretical PDF profile......The purpose of this study is to investigate the use of multivariate data analysis for powder X-ray diffraction-pair-wise distribution function (PXRD-PDF) data to detect phase separation in freeze-dried binary amorphous systems. Polymer-polymer and polymer-sugar binary systems at various ratios were...

  16. Accretion Disks Around Binary Black Holes: A Quasistationary Model

    CERN Document Server

    Liu, Yuk Tung

    2010-01-01

    Tidal torques acting on a gaseous accretion disk around a binary black hole can create a gap in the disk near the orbital radius. At late times, when the binary inspiral timescale due to gravitational wave emission becomes shorter than the viscous timescale in the disk, the binary decouples from the disk and eventually merges. Prior to decoupling the balance between tidal and viscous torques drives the disk to a quasistationary equilibrium state, perturbed slightly by small amplitude, spiral density waves emanating from the edges of the gap. We consider a black hole binary with a companion of smaller mass and construct a simple Newtonian model for a geometrically thin, Keplerian disk in the orbital plane of the binary. We solve the disk evolution equations in steady state to determine the quasistationary, (orbit-averaged) surface density profile prior to decoupling. We use our solution, which is analytic up to simple quadratures, to compute the electromagnetic flux and approximate radiation spectrum during th...

  17. Fluid-fluid interaction during miscible and immiscible displacement under ultrasonic waves

    Science.gov (United States)

    Hamida, T.; Babadagli, T.

    2007-12-01

    This paper aims at identifying and analyzing the influence of high-frequency, high-intensity ultrasonic radiation at the interface between immiscible (different types of oils and aqueous solutions) and miscible (different types of oil and solvent) fluids. An extensive set of Hele-Shaw type experiments were performed for several viscosity ratios, and interfacial tension. Fractal analysis techniques were applied to quantify the degree of fingering and branching. This provided a rough assessment of the degree of perturbation generated at the interface when the capillary forces along with the viscous forces are effective. Miscible Hele-Shaw experiments were also presented to isolate the effect of viscous forces. We found that ultrasound acts to stabilize the interfacial front, and that such effect is most pronounced at low viscosity ratios.

  18. Non-modal linear stability analysis of miscible viscous fingering in a Hele-Shaw cell

    CERN Document Server

    Hota, Tapan Kumar; Mishra, Manoranjan

    2015-01-01

    For miscible viscous fingering (VF) in a Hele-Shaw cell or in two dimensional homogeneous porous media, the transient growth of disturbances is investigated by non-modal linear stability analysis (NMA). Due to the non-autonomous nature of the linearized perturbed equations, the linear stability theory prohibits using the normal mode analysis. The linearized perturbed equations for Darcy's law coupled with a convection-diffusion equation is discretized using finite difference method. The resultant matrix valued initial value problem is then solved by fourth order Runge-Kutta method, followed by a singular value decomposition (SVD) of the propagator matrix. We demonstrate the dominant perturbation that experiences the maximum amplification within the linear regime which lead to the transient growth. This feature was previously unattained in the existing linear stability methods for miscible VF. To explore the relevance of the optimal perturbation obtained from non-modal analysis of the physical system, we perfo...

  19. Study on the Miscibility and Phase Behavior of Polyoxymethylene with Novolak

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The miscibility and phase behavior of the blends of polyoxymethylene (POM)/Novolak were investigated by the cloud point method, which showed that the POM/Novolak blends exhibited a lower critical solution temperature. The melting point of POM decreased when diluted with Novolak. From the melting temperature depression of POM, a negative interaction parameter (X) between POM and Novolak was obtained. The IR spectrum revealed that the miscibility between POM and Novolak was caused by the specific interaction between the OH groups of Novolak and the ether oxygen atoms of POM. The morphology of the blends investigated by polarized light microscopy showed that the size of spherulites of POM was sharply decreased by its mixing with Novolak. This suggests that Novolak be used as a compatibilizer for POM.

  20. Miscibility of Semi-flexible Thermotropic Liquid Crystalline Copolyesteramide with Polyamide 66

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Liquid crystalline polymer-polyamide 66 (LCP/PA66) blends were compounded by usingaBrabender mixing followed by compression moulding. The LCP employed was a semi-flexible liquid crystalline copolyesteramide based on 30% (molar fraction) of p-amino benzoic acid (ABA)and 70% (molar fraction) of poly (ethylene terephthalate)(PET). The LCP/PA66 blends wereinvestigated in terms of the thermal and dynamic mechanical properties. It was found that PA66and LCP components of the blends are miscible in the molten state, but are partially miscible inthe solid state. The inclusion of the semi-flexible LCP into PA66 retards the crystallization rateof PA66. Furthermore, the melting temperature and the degree of crystallinity of PA66 are reduced considerably due to the LCP addition.

  1. Miscibility of Methylmethacrylate-co-methacrylic Acid Polymer with Magnesium, Zinc, and Manganese Sulfonated Polystyrene Ionomers

    OpenAIRE

    ALKAN, Cemil; YURTSEVEN, Nebahat; ARAS, Leyla

    2005-01-01

    The miscibility of methyl methacrylate-co-methacrylic acid polymer (MMA-MAA) with metal neutralized sulfonated polystyrene ionomers was investigated by viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared radiation spectroscopy (FTIR) techniques. Polystyrene (PS) was sulfonated by acetic anhydride and sulfuric acid and the sulfonation degree was found to be 2.6 mole percent, and 2.6 mole percent sulfonated polystyrene was neutralized by Mg, Zn, and Mn sa...

  2. Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir, Class I

    Energy Technology Data Exchange (ETDEWEB)

    Bou-Mikael, Sami

    2002-02-05

    This report demonstrates the effectiveness of the CO2 miscible process in Fluvial Dominated Deltaic reservoirs. It also evaluated the use of horizontal CO2 injection wells to improve the overall sweep efficiency. A database of FDD reservoirs for the gulf coast region was developed by LSU, using a screening model developed by Texaco Research Center in Houston. The results of the information gained in this project is disseminated throughout the oil industry via a series of SPE papers and industry open forums.

  3. Scale-up of miscible flood processes for heterogeneous reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Orr, F.M. Jr.

    1996-04-01

    Results of a wide-ranging investigation of the scaling of gas injection processes are reported. The research examines how the physical mechanisms at work during a gas injection project interact to determine process performance. In particular, the authors examine: the interactions of equilibrium phase behavior and two-phase flow that determine local displacement efficiency and minimum miscibility pressure, the combined effects of viscous fingering, gravity segregation and heterogeneity that control sweep efficiency in 2- and 3-dimensional porous media, the use of streamtube/streamline methods to create very efficient simulation technique for multiphase compositional displacements, the scaling of viscous, capillary and gravity forces for heterogeneous reservoirs, and the effects of the thin films and spreading behavior on three-phase flow. The following key results are documented: rigorous procedures for determination of minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME) for miscibility have been developed for multicomponent systems; the complex dependence of MMP`s for nitrogen/methane floods on oil and injection gas composition observed experimentally is explained for the first time; the presence of layer-like heterogeneities strongly influences the interplay of gravity segregation and viscous fingering, as viscous fingers adapt to preferential flow paths and low permeability layers restrict vertical flow; streamtube/streamline simulation techniques are demonstrated for a variety of injection processes in 2 and 3 dimensions; quantitative scaling estimates for the transitions from capillary-dominated to gravity-dominated to viscous-dominated flows are reported; experimental results are given that demonstrate that high pressure CO{sub 2} can be used to generate low IFT gravity drainage in fractured reservoirs if fractures are suitably connected; and the effect of wetting and spreading behavior on three-phase flow is described. 209 refs.

  4. Understanding surface interactions in aqueous miscible organic solvent treated layered double hydroxides.

    OpenAIRE

    Erastova, Valentina; Degiacomi, Matteo T.; O'Hare, Dermot; Greenwell, H. Chris

    2016-01-01

    Layered materials are of interest for use in a wealth of technological applications, many of which require a high surface area for optimal properties and performance. Recently, an industrially scalable method to create high surface area layered double hydroxide (LDH) materials, which may be readily dispersed in non-polar solvents, has been developed. This method involves treatment of LDHs with aqueous miscible organic (AMO) solvents. Here, molecular modeling is exploited to elucidate the AMO ...

  5. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, Reid B.; Schechter, David S.

    1999-10-15

    The goal of this project is to improve the efficiency of miscible CO2 floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the second year of the three-year project that will be exploring three principles: (1) Fluid and matrix interactions (understanding the problems). (2) Conformance control/sweep efficiency (solving the problems. 3) Reservoir simulation for improved oil recovery (predicting results).

  6. Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends

    Directory of Open Access Journals (Sweden)

    2010-08-01

    Full Text Available The main purposes were evaluating the influence of different starches on the miscibility with Poly(ethylene oxide (PEO and their effects on the spherulite growth rate. Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends consisting of different w/w ratios (100/0, 95/05, 90/10, 80/20, 70/30, 65/35 and 60/40 was investigated. This analysis was based on the depression in the equilibrium melting temperature (Tm0. By treating the data of thermal analysis (Differential Scanning Calorimetry – DSC with Nishi-Wang equation, a positive value (0.68 was found for the interaction parameter of PEO/cationic starch. For PEO/hydrophobic starch blends, a negative value (–0.63 was obtained for the interaction parameter. The results suggested that PEO/cationic starch system should be immiscible. However, the system PEO/hydrophobic starch was considered to be miscible in the whole range of studied compositions. Through optical microscopy analysis, it was concluded that the spherulite growth rate is significantly affected by changing the amount and the type of starch as well.

  7. Solid state drug-polymer miscibility studies using the model drug ABT-102.

    Science.gov (United States)

    Jog, Rajan; Gokhale, Rajeev; Burgess, Diane J

    2016-07-25

    Amorphous solid dispersions typically suffer storage stability issues due to: their amorphous nature, high drug loading, uneven drug:stabilizer ratio and plasticization effects as a result of hygroscopic excipients. An extensive solid state miscibility study was conducted to aid in understanding the mechanisms involved in drug/stabilizer interactions. ABT-102 (model drug) and nine different polymers with different molecular weights and viscosities were selected to investigate drug/polymer miscibility. Three different polymer:drug ratios (1:3, 1:1 and 3:1, w/w) were analyzed using: DSC, FTIR and PXRD. Three different techniques were used to prepare the amorphous solid dispersions: serial dilution, solvent evaporation and spray drying. Spray drying was the best method to obtain amorphous solid dispersions. However, under certain conditions amorphous formulations could be obtained using solvent evaporation. Melting point depression was used to calculate interaction parameters and free energy of mixing for the various drug polymer mixtures. The spray dried solid dispersions yielded a negative free energy of mixing which indicated strong drug-polymer miscibility compared to the solvent evaporation and serial dilution method. Soluplus was the best stabilizer compared to PVP and HPMC, which is probably a consequence of strong hydrogen bonding between the two CO moieties of soluplus and the drug NH moieities.

  8. Miscible viscous fingering involving viscosity changes of the displacing fluid by chemical reactions

    Science.gov (United States)

    Nagatsu, Yuichiro; Iguchi, Chika; Matsuda, Kenji; Kato, Yoshihito; Tada, Yutaka

    2010-02-01

    In our previous study, we experimentally studied the effects of changes in the viscosity of the displaced more-viscous liquid by instantaneous reactions on miscible viscous fingering pattern [Y. Nagatsu, K. Matsuda, Y. Kato, and Y. Tada, "Experimental study on miscible viscous fingering involving viscosity changes induced by variations in chemical species concentrations due to chemical reactions," J. Fluid Mech. 571, 475 (2007)]. In the present study, experiments have been performed on the miscible viscous fingering involving changes in the viscosity of the displacing less-viscous liquid by instantaneous reactions in a radial Hele-Shaw cell. We have found that the shielding effect is suppressed and the fingers are widened when the viscosity is increased. As a result, the reaction makes the fingering pattern denser. In contrast, the shielding effect is enhanced, and the fingers are narrowed when the viscosity is decreased. As a result, the reaction makes the fingering pattern less dense. These results are essentially same as those obtained by the above-mentioned previous study. This shows that the effects of changes in the viscosity due to the instantaneous reactions are independent of whether the changes occur in the displaced liquid or in the displacing liquid. A mechanism for the independence is discussed.

  9. The Effect of Molecular Structure and Environment on the Miscibility and Diffusivity in Polythiophene-Methanofullerene Bulk Heterojunctions: Theory and Modeling with the RISM Approach

    Directory of Open Access Journals (Sweden)

    Alexander E. Kobryn

    2016-04-01

    Full Text Available Although better means to model the properties of bulk heterojunction molecular blends are much needed in the field of organic optoelectronics, only a small subset of methods based on molecular dynamics- and Monte Carlo-based approaches have been hitherto employed to guide or replace empirical characterization and testing. Here, we present the first use of the integral equation theory of molecular liquids in modelling the structural properties of blends of phenyl-C61-butyric acid methyl ester (PCBM with poly(3-hexylthiophene (P3HT and a carboxylated poly(3-butylthiophene (P3BT, respectively. For this, we use the Reference Interaction Site Model (RISM with the Universal Force Field (UFF to compute the microscopic structure of blends and obtain insight into the miscibility of its components. Input parameters for RISM, such as optimized molecular geometries and charge distribution of interaction sites, are derived by the Density Functional Theory (DFT methods. We also run Molecular Dynamics (MD simulation to compare the diffusivity of the PCBM in binary blends with P3HT and P3BT, respectively. A remarkably good agreement with available experimental data and results of alternative modelling/simulation is observed for PCBM in the P3HT system. We interpret this as a step in the validation of the use of our approach for organic photovoltaics and support of its results for new systems that do not have reference data for comparison or calibration. In particular, for the less-studied P3BT, our results show that expectations about its performance in binary blends with PCBM may be overestimated, as it does not demonstrate the required level of miscibility and short-range structural organization. In addition, the simulated mobility of PCBM in P3BT is somewhat higher than what is expected for polymer blends and falls into a range typical for fluids. The significance of our predictive multi-scale modelling lies in the insights it offers into nanoscale

  10. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    2006-01-01

    Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

  11. Binary Oscillatory Crossflow Electrophoresis

    Science.gov (United States)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  12. Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys

    OpenAIRE

    2011-01-01

    For a wide class of technologically relevant compound III-V and II-VI semiconductor materials AC and BC mixed crystals (alloys) of the type A(x)B(1-x)C can be realized. As the electronic properties like the bulk band gap vary continuously with x, any band gap in between that of the pure AC and BC systems can be obtained by choosing the appropriate concentration x, granted that the respective ratio is miscible and thermodynamically stable. In most cases the band gap does not vary linearly with...

  13. Binary mask programmable hologram.

    Science.gov (United States)

    Tsang, P W M; Poon, T-C; Zhou, Changhe; Cheung, K W K

    2012-11-19

    We report, for the first time, the concept and generation of a novel Fresnel hologram called the digital binary mask programmable hologram (BMPH). A BMPH is comprised of a static, high resolution binary grating that is overlaid with a lower resolution binary mask. The reconstructed image of the BMPH can be programmed to approximate a target image (including both intensity and depth information) by configuring the pattern of the binary mask with a simple genetic algorithm (SGA). As the low resolution binary mask can be realized with less stringent display technology, our method enables the development of simple and economical holographic video display.

  14. Critical mixing in monomolecular films : pressure-composition phase diagram of a two-dimensional binary mixture

    OpenAIRE

    Hirshfeld, C.L.; Seul, M.

    1990-01-01

    The pressure-composition phase diagram of mixed monolayers of dimyristoyl phosphatidylcholine (DMPC) and cholesterol at a temperature of 23.5 °C is derived by numerical analysis of pressure-area isotherms and corroborated by direct fluorescence microscopic observations. We identify a fluid-fluid miscibility gap, terminated by an upper critical point which is accessible near room temperature. We propose that the coexisting mixed phases of cholesterol and DMPC contain the phospholipid in two di...

  15. RE170、RE170/R227ea与矿物油的互溶性评价%Miscibility evaluation of RE170 and RE170/R227ea with a mineral oil

    Institute of Scientific and Technical Information of China (English)

    田田; 杨昭; 吴曦; 余壮壮

    2015-01-01

    Refrigerant R22 is scheduled to be phased out and new and environmentally friendly refrigerants RE170 and RE170/R227ea have promising application. Miscibility of these refrigerants with lubricants has a large influence on working effect of the refrigerating system. For this reason, an experimental apparatus for testing miscibility of new refrigerants with lubricants was established based on standard SH/T 0699—2000. The miscibility values of promising refrigerants RE170 and mixed refrigerant RE170/R227ea with a mineral oil were studied. RE170 and the mineral oil were completely miscible at−50℃, as oil proportion changed from 10%to 60%. When R227ea mass fraction in mixed refrigerant RE170/R227ea changed from 35% to 60% and oil proportion was specified at 14.6%±0.5%, low phase separation temperature increased with increasing R227ea. When R227ea mass fraction was below 38%, the mixed refrigerant and mineral oil became miscible even at−50℃. When R227ea mass fraction was over 55%, the mixed refrigerant and mineral oil were immiscible even at room temperature. Finally, by combining the methods of empirical equation and solubility parameter, a new evaluation method was proposed to evaluate the miscibility of pure refrigerants and binary refrigerant mixtures with the mineral oil.%随着制冷剂R22逐步淘汰,RE170、RE170/R227ea新型环保制冷剂有应用前景,其和润滑油能否互溶直接影响制冷系统的使用效果。根据标准SH/T 0699—2000建立了一套制冷剂和润滑油的互溶性测试系统,对RE170、RE170/R227ea和矿物油的互溶性进行了试验研究。结果表明:RE170的矿物油溶液在含油率为10%~60%时,当温度低至−50℃时没有出现分层或絮状物,二者互溶性非常好;混合制冷剂RE170/R227ea的矿物油溶液在含油率为14.6%±0.5%的基准情况下,当R227ea的质量分数在35%~60%变动时RE170/R227ea和矿物油的低温两相分离温度随R227ea含量增加而

  16. Investigating miscibility and molecular mobility of nifedipine-PVP amorphous solid dispersions using solid-state NMR spectroscopy.

    Science.gov (United States)

    Yuan, Xiaoda; Sperger, Diana; Munson, Eric J

    2014-01-06

    Solid-state NMR (SSNMR) (1)H T1 and T1ρ relaxation times were used to evaluate the miscibility of amorphous solid dispersions of nifedipine (NIF) and polyvinylpyrrolidone (PVP) prepared by three different methods: melt quenching in the typical lab setting, spray drying and melt quenching in the NMR rotor while spinning. Of the five compositions prepared by melt quenching in the lab setting, the 95:5 and 90:10 NIF:PVP (w:w) amorphous solid dispersions were not miscible while 75:25, 60:40, and 50:50 NIF:PVP dispersions were miscible by the (1)H T1ρ measurements. The domain size of the miscible systems was estimated to be less than 4.5 nm. Amorphous solid dispersions with composition of 90:10 NIF:PVP prepared by spray drying and melt quenching in the NMR rotor showed miscibility by (1)H T1ρ values. Variable-temperature SSNMR (1)H T1ρ relaxation measurements revealed a change in relaxation time at approximately 20 °C below Tg, suggesting increased molecular mobility above that temperature.

  17. Measurements of viscosity and permeability of two phase miscible fluid flow in rock cores.

    Science.gov (United States)

    Williams, J L; Taylor, D G

    1994-01-01

    This paper describes the application of 1H magnetic resonance imaging (MRI) to the measurement of fluid viscosity and rock core plug permeability during two phase miscible displacements in certain rock types. The core plug permeability was determined by monitoring glycerol solutions displacing D2O. Simple physical principles were used to calculate the core permeability from the measured displacement angle for a set of Lochaline sandstone core plugs. In a further experiment the viscosity of polyacrylamide solution 1500 ppm was determined in the core plug. The permeability and viscosity results compared well to conventional core analysis methods.

  18. Low-Temperature Miscibility of Ethanol-Gasoline-Water Blends in Flex Fuel Applications

    DEFF Research Database (Denmark)

    Johansen, T.; Schramm, Jesper

    2009-01-01

    The miscibility of blends of gasoline and hydrous ethanol was investigated experimentally at - 25 degrees C and - 2 degrees C. Furthermore, the maximum water content was found for ethanol in flex fuel blends. The results strongly indicate that blends containing ethanol with a water content above...... that of the ethanol/water azeotrope (4.4% water by mass) can be used as Flex Fuel blends together with gasoline at ambient temperatures of 25 degrees C and 2 degrees C, without phase separation occurring. Additionally, it was shown that the ethanol purity requirement of ethanol-rich flex fuel blends falls...... with increasing ethanol content in the gasoline-rich flex fuel blend....

  19. Mixed Method for Compressible Miscible Displacement with Dispersion in Porous Media

    Institute of Scientific and Technical Information of China (English)

    Chunguang Chen

    2007-01-01

    Compressible miscible displacement of one fluid by another in porous media is modelled by a nonlinear parabolic system. A finite element procedure is introduced to approximate the concentration of one fluid and the pressure of the mixture. The concentration is treated by a Galerkin method while the pressure is treated by a parabolic mixed finite element method. The effect of dispersion,which is neglected in [1],is considered. Optimal order estimates in L2 are derived for the errors in the approximate solutions.

  20. NUMERICAL METHODS FOR MISCIBLE DISPLACEMENT IN POROUS MEDIA INFLUENCED BY MOBILE WATER AND IMMOBILE WATER

    Institute of Scientific and Technical Information of China (English)

    崔明; 梁栋

    2002-01-01

    The numerical methods for miscible displacment in aggregated or sorbing medium areconsidered. A mixed finite element method is adopted for the pressure equation. The concentra-tion in the mobile water is approximated by a combination of a Galerkin finite element method andthe method of characteristics and the concentration in immobile water is approximated by a stan-dard Galerkin method. The moving mesh technique which depends on time t is adopted here. Themoving meshes can vary in different spacial domains with different variable times. Optima errorestimates in energy norm and L2 norm are obtained under certain constraints.

  1. Miscibility and Molecular Orientation of Carbazole in Mixed Langmuir and Langrnuir-Blodgett Films

    Institute of Scientific and Technical Information of China (English)

    Md. N. Islam; D. Bhattacharjee; S. A. Hussain

    2007-01-01

    We report the miscibility and molecular orientation of carbazole (CA) molecules in the mixed Langmuir and Langmuir-Blodgett (LB) films of CA in polymethyl methacrylate (PMMA) and stearic acid (SA) matrices. The r-A isotherm confirms the formation of stable Langmuir films of CA mixed with either PMMA or SA at airwater interface. Characteristics of area per molecule versus molefraction and collapse pressure versus molefraction reveal complete demixing of CA and the matrix PMMA/SA molecules in the mixed films. Absorption spectroscopy certainly confirms the fact that CA molecules have preferred orientation on the substrate of the LB films.

  2. Investigating the Correlation between Miscibility and Physical Stability of Amorphous Solid Dispersions Using Fluorescence-Based Techniques.

    Science.gov (United States)

    Tian, Bin; Tang, Xing; Taylor, Lynne S

    2016-11-07

    The purpose of this study was to investigate the feasibility of using a fluorescence-based technique to evaluate drug-polymer miscibility and to probe the correlation between miscibility and physical stability of amorphous solid dispersions (ASDs). Indomethacin-hydroxypropyl methylcellulose (IDM-HPMC), indomethacin-hydroxypropyl methylcellulose acetate succinate, and indomethacin-polyvinylpyrrolidone (IDM-PVP) were used as model systems. The miscibility of the IDM-polymer systems was evaluated by fluorescence spectroscopy, fluorescence imaging, differential scanning calorimetry (DSC), and infrared (IR) spectroscopy. The physical stability of IDM-polymer ASDs stored at 40 °C was evaluated using fluorescence imaging and X-ray diffraction (XRD). The experimentally determined miscibility limit of IDM with the polymers was 50-60%, 20-30%, and 70-80% drug loading for HPMC, HPMCAS, and PVP, respectively. The X-ray results showed that for IDM-HPMC ASDs, samples with a drug loading of less than 50% were maintained in amorphous form during the study period, while samples with drug loadings higher than 50% crystallized within 15 days. For IDM-HPMCAS ASDs, samples with drug loading less than 30% remained amorphous, while samples with drug loadings higher than 30% crystallized within 10 days. IDM-PVP ASDs were found to be resistant to crystallization for all compositions. Thus, a good correlation was observed between phase separation and reduced physical stability, suggesting that miscibility is indeed an important ASDs characteristic. In addition, fluorescence-based techniques show promise in the evaluation of drug-polymer miscibility.

  3. Interacting binary stars

    CERN Document Server

    Sahade, Jorge; Ter Haar, D

    1978-01-01

    Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

  4. MISCIBILITY, THERMAL STABILITY AND RETENTION OF PVP FOR CROSSLINKED PVA/PVP BLENDS

    Institute of Scientific and Technical Information of China (English)

    LIANG Guomei; ZHANG Kun; FENG Rongyin

    1994-01-01

    The thermal behavior, miscibility, crystallite conformation and thermal stability of crosslinked(CL-) PVA/PVP blends were studied by DSC and TG methods, respectively. DSC results showed that in the blend, the crystallinity,Tm and Tc of PVA were obviously lower than those of pure PVA; the crystal growth changed from three dimensional to two dimensional and only a single Tg was detected . These facts demonstrated that this crystalline and amorphous blend have good miscibility. TG curves showed that providing the quantity of K2S2O8 added is more than 3 wt % ,in the blends PVA will form a stable CL-network, whose thermal degradation temperature was near to that of PVP. But crosslinking reaction will not take place for PVP. The processes of thermal degradation of CL-blends are based on combining both the thermal degradation of PVP and that of PVA crosslinked with corresponding quantity of K2S2O8 CL-agent, respectively.The UV measurements showed that 75 wt% of PVP may be remained in CL-blend hydrogels crosslinked by adding (3- 5 wt % )K2S2O8.This is mainly due to the stable CL-network formed and the good compatibility and proper entanglement between the composites in the CL-blends.

  5. Stability of viscosity stratified flows down an incline: Role of miscibility and wall slip

    CERN Document Server

    Ghosh, Sukhendu

    2016-01-01

    The effects of wall velocity slip on the linear stability of a gravity-driven miscible two-fluid flow down an incline are examined. The fluids have the matched density but different viscosity. A smooth viscosity stratification is achieved due to the presence of a thin mixed layer between the fluids. The results show that the presence of slip exhibits a promise for stabilizing the miscible flow system by raising the critical Reynolds number at the onset and decreasing the bandwidth of unstable wave numbers beyond the threshold of the dominant instability. This is different from its role in the case of a single fluid down a slippery substrate where slip destabilizes the flow system at the onset. Though the stability properties are analogous to the same flow system down a rigid substrate, slip is shown to delay the surface mode instability for any viscosity contrast. It has a damping/promoting effect on the overlap modes (which exist due to the overlap of critical layer of dominant disturbance with the mixed lay...

  6. Mechanism evaluation of carbon dioxide miscible flooding : Caoshe oilfield case study

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Y.; Du, Z.; Sun, L. [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu (China); Southwest Petroleum Univ., Chengdu (China); Yu, K.; Liu, W.; Chen, Z. [SINOPEC (China). East China Oil Field Branch

    2009-07-01

    This paper investigated the mechanisms of a carbon dioxide (CO{sub 2}) miscible flooding project at an oilfield in China. Laboratory tests included pressure-volume-temperature (PVT), CO{sub 2} injection swelling, and slim tube tests. Results of the experimental tests were then used to construct an equations-of-state (EOS) compositional model with a 1D and 2D profile of an injector-production well group. Changes in fluid composition and the viscosity and density of the oil and vapor phases were characterized as well as the interfacial tension between oil and gas along the grids during the CO{sub 2} injection process. The effect of gas volume and injection pressure on fluid properties was also investigated. the study showed that the minimum miscibility pressure (MMP) of the project is 30 MPa. The model content of the CO{sub 2} in oil phase can be reacted at a formation pressure of 32 MPa with a 70 per cent oil phase. A continuous CO{sub 2} injection method with formation pressures above the MMP was recommended for the field. 10 refs., 3 tabs., 22 figs.

  7. Flow and Reactive Transport of Miscible and Immiscible Solutions in Fractured & Porous Media

    Science.gov (United States)

    Ryerson, F. J.; Ezzedine, S. M.; Antoun, T.

    2012-12-01

    Miscible and immiscible flows are important phenomena encountered in many industrial and engineering applications such as hydrothermal systems, oil and gas reservoirs, salt/water intrusion, geological carbon sequestration etc… Under the influence of gravity, the flow of fluids with sufficiently large density ratios may become unstable leading to instabilities, mixing and in some instances reactions at the interfacial contact between fluids. Flow is governed by a combination of momentum and mass conservation equations that describe the flow of the fluid phase and a convection-diffusion equation describing the change of concentration in the fluid phase. When hydrodynamic instabilities develop it may be difficult to use standard grid-based methods to model miscible/immiscible flow because the domains occupied by fluids evolve constantly with time. In the current study, adaptive mesh refinement finite elements method has been used to solve for flow and transport equations. Furthermore, a particle tracking scheme has also been implemented to track the kinematics of swarm of particles injected into the porous fractured media to quantify surface area, sweeping zones, and their impact on porosity changes. Spatial and temporal moments of the fingering instabilities and the development of reaction zones and the impact of kinetic reaction at the fluid/solution interfaces have also been analyzed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  8. Experimental study of 3D Rayleigh-Taylor convection between miscible fluids in a porous medium

    Science.gov (United States)

    Nakanishi, Yuji; Hyodo, Akimitsu; Wang, Lei; Suekane, Tetsuya

    2016-11-01

    The natural convection of miscible fluids in porous media has applications in several fields, such as geoscience and geoengineering, and can be employed for the geological storage of CO2. In this study, we used X-ray computer tomography to visualize 3D fingering structures associated with the Rayleigh-Taylor instability between miscible fluids in a porous medium. In the early stages of the onset of the Rayleigh-Taylor instability, a fine crinkling pattern gradually appeared at the interface. As the wavelength and amplitude increased, descending fingers formed on the interface and extended vertically downward; in addition, ascending and highly symmetric fingers formed. The adjacent fingers were cylindrical in shape and coalesced to form large fingers. The fingers appearing on the interface tended to become finer with increasing Rayleigh number, which is consistent with linear perturbation theory. When the Péclet number exceeded 10, transverse dispersion increased the finger diameter and enhanced the finger coalescence, strongly impacting the decrease in finger number density. When mechanical dispersion was negligible, the finger-extension velocity and the dimensionless mass-transfer rate scaled with the characteristic velocity and the Rayleigh number with an appropriate length scale. Mechanical dispersion not only reduced the onset time but also enhanced the mass transport.

  9. Forming Nanoparticle Monolayers at Liquid-Air Interfaces by Using Miscible Liquids.

    Science.gov (United States)

    Zhang, Datong; Hu, Jiayang; Kennedy, Kathleen M; Herman, Irving P

    2016-08-23

    One standard way of forming monolayers (MLs) of nanoparticles (NPs) is to drop-cast a NP dispersion made using one solvent onto a second, immiscible solvent; after this upper solvent evaporates, the NP ML can be transferred to a solid substrate by liftoff. We show that this previously universal use of only immiscible solvent pairs can be relaxed and close-packed, hexagonally ordered NP monolayers can self-assemble at liquid-air interfaces when some miscible solvent pairs are used instead. We demonstrate this by drop-casting an iron oxide NP dispersion in toluene on a dimethyl sulfoxide (DMSO) liquid substrate. The NPs are energetically stable at the DMSO surface and remain there even with solvent mixing. Excess NPs coagulate and precipitate in the DMSO, and this limits NPs at the surface to approximately 1 ML. The ML domains at the surface nucleate independently, which is in contrast to ML growth at the receding edge of the drying drop, as is common in immiscible solvent pair systems and seen here for the toluene/diethylene glycol immiscible solvent pair system. This new use of miscible solvent pairs can enable the formation of MLs for a wider range of NPs.

  10. Miscible and immiscible experiments on the Rayleigh-Taylor instability using planar laser induced fluorescence visualization

    Science.gov (United States)

    Mokler, Matthew; Roberts, Michael; Jacobs, Jeffrey

    2013-11-01

    Incompressible Rayleigh-Taylor instability experiments are presented in which two stratified liquids having Atwood number of 0.2 are accelerated in a vertical linear induction motor driven drop tower. A test sled having only vertical freedom of motion contains the experiment tank and visualization equipment. The sled is positioned at the top of the tower within the linear induction motors and accelerated downward causing the initially stable interface to be unstable and allowing the Rayleigh-Taylor instability to develop. Forced and unforced experiments are conducted using both immiscible and miscible liquid combinations. Forced initial perturbations are produced by vertically oscillating the test sled prior to the start of acceleration. The interface is visualized using a 445 nm laser light source that illuminates a fluorescent dye mixed in one of the fluids. The resulting fluorescent images are recorded using a monochromatic high speed video camera. The laser beam is synchronously swept across the fluorescent fluid, at the frame rate of the camera, exposing a single plane of the interface allowing for the measurement of spike and bubble growth. Comparisons between miscible and immiscible mixing layer distributions are made from the resulting interface concentration profiles.

  11. Miscibility and Hydrogen Bonding in Blends of Poly(4-vinylphenol/Poly(vinyl methyl ketone

    Directory of Open Access Journals (Sweden)

    Hana Bourara

    2014-10-01

    Full Text Available The miscibility and phase behavior of poly(4-vinylphenol (PVPh with poly(vinyl methyl ketone (PVMK was investigated by differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. It was shown that all blends of PVPh/PVMK are totally miscible. A DSC study showed the apparition of a single glass transition (Tg over their entire composition range. When the amount of PVPh exceeds 50% in blends, the obtained Tgs are found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are capable of forming interpolymer complexes. FTIR analysis revealed the existence of preferential specific interactions via hydrogen bonding between the hydroxyl and carbonyl groups, which intensified when the amount of PVPh was increased in blends. Furthermore, the quantitative FTIR study carried out for PVPh/PVMK blends was also performed for the vinylphenol (VPh and vinyl methyl ketone (VMK functional groups. These results were also established by scanning electron microscopy study (SEM.

  12. The Tarantula Massive Binary Monitoring: I. Observational campaign and OB-type spectroscopic binaries

    CERN Document Server

    Almeida, L A; Taylor, W; Barbá, R; Bonanos, A; Crowther, P; Damineli, A; de Koter, A; de Mink, S E; Evans, C J; Gieles, M; Grin, N J; Hénault-Brunet, V; Langer, N; Lennon, D; Lockwood, S; Apellániz, J Maíz; Moffat, A F J; Neijssel, C; Norman, C; Ramírez-Agudelo, O H; Richardson, N D; Schootemeijer, A; Shenar, T; Soszyński, I; Tramper, F; Vink, J S

    2016-01-01

    Massive binaries (MBs) play a crucial role in the Universe and knowing the distributions of their orbital parameters (OPs) is important for a wide range of topics, from stellar feedback to binary evolution channels, from the distribution of supernova types to gravitational wave progenitors. Yet, no direct measurements exist outside the Milky Way. The Tarantula Massive Binary Monitoring was designed to help fill this gap by obtaining multi-epoch radial velocity monitoring of 102 MBs in the 30 Dor. In this paper, we analyse 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined and 31 double-lined spectroscopic binaries. Overall, the OPs and binary fraction are remarkably similar across the 30 Dor region and compared to existing Galactic samples (GSs). This indicates that within these domains environmental effects are of second order in shaping the properties of MBs. A small difference is found in the distribu...

  13. Thermophysical properties and phase equilibria study of the binary systems {l_brace}N-hexylquinolinium bis(trifluoromethylsulfonyl)imide + aromatic hydrocarbons, or an alcohol{r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula, E-mail: ula@ch.pw.edu.p [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001 (South Africa); Zawadzki, Maciej [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Zwolinska, Magdalena [Department of Ergonomics, Laboratory of Thermal Loads, Central Institute for Labour Protection-National Research Institute, Czerniakowska 16, 00-701 Warsaw (Poland)

    2011-05-15

    Research highlights: We synthesized new ionic liquid, [HQuin][NTf{sub 2}] with low viscosity, and low density. We found high heat capacity, high enthalpy of melting and low melting temperature. HQuin][NTf{sub 2}] is proposed for possible use in the phase change materials (PCM). We examine phase equilibrium changes, SLE and LLE with hydrocarbons and alcohols. [HQuin][NTf{sub 2}] may be proposed as entrainer for the separation proceses. - Abstract: The new quinolinium ionic liquid has been synthesised as a continuation of our work with quinolinium-based ionic liquids (ILs). The work includes specific basic characterisation of synthesized compounds: N-hexylquinolinium bromide, [HQuin][Br] and N-hexylquinolinium bis{l_brace}(trifluoromethyl)sulfonyl{r_brace}imide [HQuin][NTf{sub 2}] by NMR spectra, elementary analysis and water content. The basic thermal properties of the pure [HQuin][NTf{sub 2}] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity have been measured using a differential scanning microcalorimetry technique (DSC) and thermal analysis instrument (TA). Densities and viscosities were determined as a function of temperature. Phase equilibria for the binary systems: {l_brace}[HQuin][NTf{sub 2}]) + aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol){r_brace} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (270 to 320) K. For all the binary systems with benzene and alkylbenzenes, the eutectic diagrams were observed with immiscibility gap in the liquid phase beginning from (0.13 to 0.28) mole fraction of the IL with very high an upper critical solution temperature (UCST). For mixtures with alcohols, the complete miscibility was observed for 1-butanol and immiscibility with UCST in the liquid phase for the remaining alcohols. The typical

  14. DSC study of phase transitions of cephalin pseudo-binary systems in excess water

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1999-01-01

    The gel-liquid crystal phase transitions of the pseudo-binary systems of cephalins DMPE and DHPE in excess water were studied by differential scanning calorimetry. The phase diagram of the pseudo-binary systems has been given. The experiments showed that the partial phase separation in gel phase might occur at least at the mole fractions of DHPE below 0.1. The analysis by the model of ideal solution showed that both the cephalins were non-ideally miscible both in the gel phases and in the liquid crystal phases. The analysis by the model of regular solution showed that all the non-ideality parameters in the gel phases were larger than those in the liquid crystal phases at the same temperature. All the non-ideality parameters were not constant, but rather dependent on temperature.

  15. The Tarantula Massive Binary Monitoring. I. Observational campaign and OB-type spectroscopic binaries

    Science.gov (United States)

    Almeida, L. A.; Sana, H.; Taylor, W.; Barbá, R.; Bonanos, A. Z.; Crowther, P.; Damineli, A.; de Koter, A.; de Mink, S. E.; Evans, C. J.; Gieles, M.; Grin, N. J.; Hénault-Brunet, V.; Langer, N.; Lennon, D.; Lockwood, S.; Maíz Apellániz, J.; Moffat, A. F. J.; Neijssel, C.; Norman, C.; Ramírez-Agudelo, O. H.; Richardson, N. D.; Schootemeijer, A.; Shenar, T.; Soszyński, I.; Tramper, F.; Vink, J. S.

    2017-02-01

    Context. Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way. Aims: The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region. Methods: In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries. Results: Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus's core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2-O7) tend to have shorter orbital periods than later spectral types (O9.2-O9.7). Conclusions: Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the

  16. Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation.

    Science.gov (United States)

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Tohru; Tanaka, Kazuyuki; Kitamura, Satoshi; Takakura, Asako; Hayashi, Takashi; Muranushi, Noriyuki

    2007-08-01

    The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an

  17. Molecular dynamics simulation of a binary mixture near the lower critical point.

    Science.gov (United States)

    Pousaneh, Faezeh; Edholm, Olle; Maciołek, Anna

    2016-07-07

    2,6-lutidine molecules mix with water at high and low temperatures but in a wide intermediate temperature range a 2,6-lutidine/water mixture exhibits a miscibility gap. We constructed and validated an atomistic model for 2,6-lutidine and performed molecular dynamics simulations of 2,6-lutidine/water mixture at different temperatures. We determined the part of demixing curve with the lower critical point. The lower critical point extracted from our data is located close to the experimental one. The estimates for critical exponents obtained from our simulations are in a good agreement with the values corresponding to the 3D Ising universality class.

  18. Adaptive enriched Galerkin methods for miscible displacement problems with entropy residual stabilization

    Science.gov (United States)

    Lee, Sanghyun; Wheeler, Mary F.

    2017-02-01

    We present a novel approach to the simulation of miscible displacement by employing adaptive enriched Galerkin finite element methods (EG) coupled with entropy residual stabilization for transport. In particular, numerical simulations of viscous fingering instabilities in heterogeneous porous media and Hele-Shaw cells are illustrated. EG is formulated by enriching the conforming continuous Galerkin finite element method (CG) with piecewise constant functions. The method provides locally and globally conservative fluxes, which are crucial for coupled flow and transport problems. Moreover, EG has fewer degrees of freedom in comparison with discontinuous Galerkin (DG) and an efficient flow solver has been derived which allows for higher order schemes. Dynamic adaptive mesh refinement is applied in order to reduce computational costs for large-scale three dimensional applications. In addition, entropy residual based stabilization for high order EG transport systems prevents spurious oscillations. Numerical tests are presented to show the capabilities of EG applied to flow and transport.

  19. Wavelength Analysis of Interface between Two Miscible Solutions Observed in Formation of Fractal Pattern

    Science.gov (United States)

    Shimokawa, Michiko; Takami, Toshiya

    2014-04-01

    When a droplet of a higher-density solution (HDS) is placed on top of a lower-density solution (LDS), the HDS draws a fractal pattern on the surface of the LDS. Before the fractal pattern is formed, a stick-like pattern with a periodic structure emerges in a region surrounding the surface pattern due to interfacial instability. We experimentally measure the wavelength of this stick-like pattern. The wavelength increases with the volume of the HDS and is independent of the viscosities of the two solutions. To understand the stick generation, we propose a model of miscible viscous fingering whose boundary conditions are similar to those of the experiments. The wavelength obtained from the model agrees with the experimentally obtained wavelength. The formation of the fractal pattern is discussed by comparing it with the viscous fingering.

  20. Acousto-optic method used to control water pollution by miscible liquids

    Science.gov (United States)

    Ferria, Kouider; Griani, Lazhar; Laouar, Naamane

    2012-05-01

    An acousto-optic (A.O.) method has been developed for controlling the quality of water mixed by miscible liquids like acetone or ethanol… The liquid mixture is filled in a rectangular glass cell, which is placed orthogonally to the incident collimated beam of light. This cell consists of a piezoelectric transducer for generating ultrasonic waves. The collimated light while passing through this cell undergoes a diffraction phenomenon. The diffracted dots are collected by a converging photographic objective and displayed in its back focal plane. The location of the diffracted dots and their intensity are sensitive to any variation of the interaction medium. This result leads to decide about the quality of the water.

  1. Derivation of models of compressible miscible displacement in partially fractured reservoirs

    Directory of Open Access Journals (Sweden)

    Catherine Choquet

    2007-07-01

    Full Text Available We derive rigorously homogenized models for the displacement of one compressible miscible fluid by another in fractured porous media. We denote by $epsilon$ the characteristic size of the heterogeneity in the medium. A parameter $alpha in [0,1]$ characterizes the cracking degree of the rock. We carefully define an adapted microscopic model which is scaled by appropriate powers of $epsilon$. We then study its limit as $epsilon o 0$. Assuming a totally fractured or a partially fractured medium, we obtain two effective macroscopic limit models. The first one is a double porosity model. The second one is of single porosity type but it still contains some effects due to the partial storage in the matrix part. The convergence is shown using two-scale convergence techniques.

  2. Dynamics, Miscibility, and Morphology in Polymer-Molecule Blends: The Impact of Chemical Functionality

    KAUST Repository

    Do, Khanh

    2015-10-22

    In the quest to improve the performance of organic bulk-heterojunction solar cells, many recent efforts have focused on developing molecular and polymer alternatives to commonly used fullerene acceptors. Here, molecular dynamics simulations are used to investigate polymer-molecule blends comprised of the polymer donor poly(3-hexylthiophene) (P3HT) with a series of acceptors based on trialkylsilylethynyl-substituted pentacene. A matrix of nine pentacene derivatives, consisting of systematic chemical variation both in the nature of the alkyl groups and electron-withdrawing moieties appended to the acene, is used to draw connections between the chemical structure of the acene acceptor and the nanoscale properties of the polymer-molecule blend. These connections include polymer and molecular diffusivity, donor-acceptor packing and interfacial (contact) area, and miscibility. The results point to the very significant role that seemingly modest changes in chemical structure play during the formation of polymer-molecule blend morphologies.

  3. Optimal Control of Partially Miscible Two-Phase Flow with Applications to Subsurface CO2 Sequestration

    KAUST Repository

    Simon, Moritz

    2013-01-01

    Motivated by applications in subsurface CO2 sequestration, we investigate constrained optimal control problems with partially miscible two-phase flow in porous media. The objective is, e.g., to maximize the amount of trapped CO2 in an underground reservoir after a fixed period of CO2 injection, where the time-dependent injection rates in multiple wells are used as control parameters. We describe the governing two-phase two-component Darcy flow PDE system and formulate the optimal control problem. For the discretization we use a variant of the BOX method, a locally conservative control-volume FE method. The timestep-wise Lagrangian of the control problem is implemented as a functional in the PDE toolbox Sundance, which is part of the HPC software Trilinos. The resulting MPI parallelized Sundance state and adjoint solvers are linked to the interior point optimization package IPOPT. Finally, we present some numerical results in a heterogeneous model reservoir.

  4. Miscibility studies of Polyethylene Glycol with Polystyrene in Toluene by Various Physical and Advanced Techniques

    Science.gov (United States)

    Padmanaban, R.; Venkatramanan, K.

    2016-10-01

    Polyethylene glycol (PEG) is a chemical that has an extensive variety of applications in the world of medicine. It is used as a base to manufacture certain medicines, assist in drug delivery, and is also used as an agent in some medical procedures. It is an osmotic laxative. Polyethylene glycol works by retaining water in the stool, resulting in softer stools and more frequent bowel movements. Polyethylene glycol does not affect glucose and electrolytes in the body. PEG refers to a hydrocarbon molecule that can have a variable size, and different sizes can have different physical properties, giving this compound a great deal of flexibility in its application. In the present study, Polyethylene Glycol (PEG) (Molar mass: 1500) is blended with Polystyrene (PS) (Molar mass: 35000) in Toluene. The miscibility nature of the poly blend is analyzed by Ultrasonic velocity, viscosity, density and refractive index techniques at 303K. The compatibility nature of the blend is confirmed by Differential Scanning Calorimetry (DSC) studies.

  5. Simulation of miscible displacement using mixed methods and a modified method of characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.E.; Russell, T.F.; Wheeler, M.F.

    1983-11-01

    Numerical dispersion and grid orientation problems with adverse mobility ratios are two of the major difficulties in the numerical simulation of enhanced recovery processes. An efficient method for modeling convection-dominated flows which greatly reduces numerical dispersion and grid orientation problems is presented and applied to miscible displacement in a porous medium. The base method utilizes characteristic flow directions to model convection and finite elements to treat the diffusion and dispersion. The characteristic approach also minimizes certain overshoot difficulties which accompany many finite element methods for problems with sharp fluid interfaces. The truncation error caused by the characteristic time-stepping technique is small, so large stable time-steps can be taken as in fully-implicit methods without the corresponding loss in accuracy.

  6. Upwind finite difference method for miscible oil and water displacement problem with moving boundary values

    Institute of Scientific and Technical Information of China (English)

    Yi-rang YUAN; Chang-feng LI; Cheng-shun YANG; Yu-ji HAN

    2009-01-01

    The research of the miscible oil and water displacement problem with moving boundary values is of great value to the history of oil-gas transport and accumulation in the basin evolution as well as to the rational evaluation in prospecting and exploiting oil-gas resources. The mathematical model can be described as a coupled system of nonlinear partial differential equations with moving boundary values. For the two-dimensional bounded region, the upwind finite difference schemes are proposed. Some techniques, such as the calculus of variations, the change of variables, and the theory of a priori estimates, are used. The optimal order l2-norm estimates are derived for the errors in the approximate solutions. The research is important both theoretically and practically for the model analysis in the field, the model numerical method, and the software development.

  7. Evaporation dynamics of a liquid drop on a non-miscible liquid bath

    Science.gov (United States)

    Pirat, Christophe; Ramos-Canut, Stella; Caupin, Frederic; wetting Team

    2016-11-01

    When a liquid drop sits on a solid surface, it is well known that the wetting and evaporation properties strongly depend on the environmental and wetting conditions. In this experimental study, we investigate the coupled spreading-evaporation dynamics of a liquid drop, made of a mixture of water and ethanol, gently deposited on a non-miscible oil bath. After a fast spreading stage due to a positive spreading parameter, the drop starts to recede while the evaporation is going on. Subsequently, a Marangoni instability develops as alcohol evaporates faster than water. In particular, depending on the initial alcohol-water ratio, a set of rim instabilities takes place. Radial droplet ejections can be observed, with various droplet speeds, sizes and frequencies.

  8. Aggregation behavior and total miscibility of fluorinated ionic liquids in water.

    Science.gov (United States)

    Pereiro, Ana B; Araújo, João M M; Teixeira, Fabiana S; Marrucho, Isabel M; Piñeiro, Manuel M; Rebelo, Luis Paulo N

    2015-02-01

    In this work, novel and nontoxic fluorinated ionic liquids (FILs) that are totally miscible in water and could be used in biological applications, where fluorocarbon compounds present a handicap because their aqueous solubility (water and biological fluids) is in most cases too low, have been investigated. The self-aggregation behavior of perfluorosulfonate-functionalized ionic liquids in aqueous solutions has been characterized using conductometric titration, isothermal titration calorimetry (ITC), surface tension measurements, dynamic light scattering (DLS), viscosity and density measurements, and transmission electron microscopy (TEM). Aggregation and interfacial parameters have been computed by conductimetry, calorimetry, and surface tension measurements in order to study various thermodynamic and surface properties that demonstrate that the aggregation process is entropy-driven and that the aggregation process is less spontaneous than the adsorption process. The novel perfluorosulfonate-functionalized ILs studied in this work show improved surface activity and aggregation behavior, forming distinct self-assembled structures.

  9. Three-dimensional miscible, porous media displacements for the quarter five-spot configuration

    Science.gov (United States)

    Riaz, Amir

    Three-dimensional miscible displacements with gravity override are investigated in homogeneous and heterogeneous porous media using high accuracy numerical simulations. Special emphasis is placed on the interpretation of the dynamics in terms of the vorticity production related to viscosity, permeability and gravity. Comparison with experimental results show that three-dimensional neutrally buoyant displacements give a better estimate of the displacement efficiency than two-dimensional displacements. Gravity override profoundly influences the flow dynamics both by creating a gravity layer where most of the displaced fluid is bypassed as well as by enhancing the horizontal and vertical mode interactions. Heterogeneous displacements are classified into regimes of viscous fingering, harmonic resonance and channeling depending upon the relative magnitudes of the viscous and permeability length scales. A complex coupling between the viscous instability and permeability spectra leads to intricate fingering patterns that profoundly influence the displacement efficiency.

  10. Miscible and immiscible, forced and unforced experiments on the Rayleigh-Taylor instability

    Science.gov (United States)

    Roberts, Michael; Mokler, Matthew; Jacobs, Jeffrey

    2012-11-01

    Experiments are presented in which an incompressible system of two liquids is accelerated to produce the Rayleigh-Taylor instability. In these experiments, the initially stable, stratified liquid combination is accelerated downward on a vertical rail system in one of two experimental apparatuses: an apparatus in which a system of weights and pulleys accelerates the liquid filled tank, or a new apparatus which uses linear induction motors to accelerate the tank to produce much greater acceleration levels. Both miscible and immiscible liquid combinations are used. In both apparatuses the resulting fluid flows are visualized with backlit imaging using LED backlights in conjunction with monochrome high-speed video cameras, both of which travel with the moving fluid filled containers. Initial perturbations are either unforced and allowed to progress from background noise or forced by vertically oscillating the liquid combination to produce parametric internal waves. The mixing layer growth rate α is determined for all cases and compared to numerical simulations and past experiments.

  11. On miscible flow in porous media: A numerical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Baigorria, R.; Ottone, L.O. (Gerencia General de Activos Tecnologicos, Florencia Varela (Argentina)); Pousa, J.L.; Filomena, D.L.; Maranon, J. (La Plata Univ. (Argentina))

    1992-01-01

    A diamond-shaped, random, two-dimensional network of interconnected capillary tubes was constructed to simulate miscible displacement numerically in porous media. An experimental technique was specially developed to measure the ratio between pore volume of displacing fluid injected up to the time of breakthrough and the total pore volume of the sample, PVI[sub b]/TPV. For low heterogeneity media, a unimodal, asymmetric, Gaussian-like tube-radius distribution was used to construct several networks from which a set of values of PVBI[sub b]/PVT was calculated and matched against those determined experimentally. For high heterogeneity media, however, a kind of ad-hoc, bimodal, tube-radius distribution had to be constructed to obtain a reasonable match. The experimental and computational difficulties that arise for very highly heterogeneous media are also discussed. 12 refs., 10 figs., 2 tabs.

  12. Experimental study of the growth of mixing zone in miscible viscous fingering

    Science.gov (United States)

    Malhotra, Sahil; Sharma, Mukul M.; Lehman, Eric R.

    2015-01-01

    An experimental study is performed to quantify the growth of the mixing zone in miscible viscous fingering. Rectilinear flow displacement experiments are performed in a Hele-Shaw cell over a wide range of viscosity ratios (1-1225) by injecting water into glycerol solutions at different flow rates. All the experiments are performed at high Peclet numbers and linear growth in mixing zone is observed. The mixing zone velocity increases with the viscosity ratio up to viscosity ratios of 340 and the trend is consistent with Koval's model. However, at higher viscosity ratios, the mixing velocity plateaus signifying no further effect of viscosity contrast on the growth of mixing zone. The front (fingertip) velocities also increase up to viscosity ratios of 340 above which the velocities plateau.

  13. Magnetic Resonance Imaging Study on the Miscibility of a CO2/n-Decane System

    Institute of Scientific and Technical Information of China (English)

    SONG Yong-Chen; ZHU Ning-Jun; LIU Yu; ZHAO Jia-Fei; LIU Wei-Guo; ZHANG Yi; ZHAO Yue-Chao; JIANG Lan-Lan

    2011-01-01

    @@ We provide a feasible method to estimate the minimum miscibility pressure(MMP)of a CO2/n-decane system by using high spatial resolution magnetic resonance imaging(MRI).During the measurement,the signal intensity of n-decane with CO2 dissolved is measured.The MRI images show that the signal intensity of n-decane decreases to zero and the interface disappears at the MMP.A good exponential growth relation is found between the signal intensity and the pressure of the CO2/n-decane system.The relationship between the MMP and the temperature is established quantitatively,which is in close agreement with previous studies.Moreover it could be used to predict the MMP of the CO2/n-decane system.%We provide a feasible method to estimate the minimum miscibility pressure (MMP) of a CO2/n-decane system by using high spatial resolution magnetic resonance imaging (MRI). During the measurement, the signal intensity of n-decane with CO2 dissolved is measured. The MRI images show that the signal intensity of n-decane decreases to zero and the interface disappears at the MMP. A good exponential growth relation is found between the signal intensity and the pressure of the Coi/n-decane system. The relationship between the MMP and the temperature is established quantitatively, which is in close agreement with previous studies. Moreover it could be used to predict the MMP of the CO2/'n-decane system.

  14. Origin of Scale-Dependent Dispersivity and Its Implications For Miscible Gas Flooding

    Energy Technology Data Exchange (ETDEWEB)

    Steven Bryant; Russ Johns; Larry Lake; Thomas Harmon

    2008-09-30

    Dispersive mixing has an important impact on the effectiveness of miscible floods. Simulations routinely assume Fickian dispersion, yet it is well established that dispersivity depends on the scale of measurement. This is one of the main reasons that a satisfactory method for design of field-scale miscible displacement processes is still not available. The main objective of this project was to improve the understanding of the fundamental mechanisms of dispersion and mixing, particularly at the pore scale. To this end, microsensors were developed and used in the laboratory to measure directly the solute concentrations at the scale of individual pores; the origin of hydrodynamic dispersion was evaluated from first principles of laminar flow and diffusion at the grain scale in simple but geometrically completely defined porous media; techniques to use flow reversal to distinguish the contribution to dispersion of convective spreading from that of true mixing; and the field scale impact of permeability heterogeneity on hydrodynamic dispersion was evaluated numerically. This project solved a long-standing problem in solute transport in porous media by quantifying the physical basis for the scaling of dispersion coefficient with the 1.2 power of flow velocity. The researchers also demonstrated that flow reversal uniquely enables a crucial separation of irreversible and reversible contributions to mixing. The interpretation of laboratory and field experiments that include flow reversal provides important insight. Other advances include the miniaturization of long-lasting microprobes for in-situ, pore-scale measurement of tracers, and a scheme to account properly in a reservoir simulator (grid-block scale) for the contributions of convective spreading due to reservoir heterogeneity and of mixing.

  15. Optimal control policies for carbon dioxide miscible flooding enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Methos, G.J.

    1986-01-01

    Optimal control theory of distributed parameter systems has been used to develop improved operational strategies for carbon dioxide miscible flooding. The optimization criterion was to maximize the net profitability of the CO/sub 2/ flood. A two-dimensional, three-phase, modified black-oil model was used to describe miscible displacement of oil. Calculus of variations was applied to find control functions that provide extreme for an objective functional which related injection costs and production revenue. Lagrange multipliers, or costate variables, were used to ensure that the constraints given by the equations of the simulation model were satisfied. Control functions computed were the carbon dioxide and water injection policies and the production wellbore pressure history. In order to avoid difficulties in obtaining a stable numerical scheme for the costate equation, a discrete formulation of the optimal control problem was developed. A steepest decent gradient search method was used to find the optimal control law. Starting functions for the algorithm described currently used strategies: a large slug of CO/sub 2/ followed by drive water; carbon dioxide injected simultaneously with water; and injection of small slugs of CO/sub 2/ alternately with slugs of water. Improvements in the cost functional from the starting functions ranged from four to eleven percent. While the optimal control law found was highly dependent upon the starting functions used to initiate the algorithm, the shape of the optimal control law was found to be unique, as was the optimal total volume of carbon dioxide injected and the optimal value of the cost functional.

  16. Stability of viscosity stratified flows down an incline: Role of miscibility and wall slip

    Science.gov (United States)

    Ghosh, Sukhendu; Usha, R.

    2016-10-01

    The effects of wall velocity slip on the linear stability of a gravity-driven miscible two-fluid flow down an incline are examined. The fluids have the matched density but different viscosity. A smooth viscosity stratification is achieved due to the presence of a thin mixed layer between the fluids. The results show that the presence of slip exhibits a promise for stabilizing the miscible flow system by raising the critical Reynolds number at the onset and decreasing the bandwidth of unstable wave numbers beyond the threshold of the dominant instability. This is different from its role in the case of a single fluid down a slippery substrate where slip destabilizes the flow system at the onset. Though the stability properties are analogous to the same flow system down a rigid substrate, slip is shown to delay the surface mode instability for any viscosity contrast. It has a damping/promoting effect on the overlap modes (which exist due to the overlap of critical layer of dominant disturbance with the mixed layer) when the mixed layer is away/close from/to the slippery inclined wall. The trend of slip effect is influenced by the location of the mixed layer, the location of more viscous fluid, and the mass diffusivity of the two fluids. The stabilizing characteristics of slip can be favourably used to suppress the non-linear breakdown which may happen due to the coexistence of the unstable modes in a flow over a substrate with no slip. The results of the present study suggest that it is desirable to design a slippery surface with appropriate slip sensitivity in order to meet a particular need for a specific application.

  17. Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; G. Paul Willhite; Don Green; Richard Pancake; JyunSyung Tsau; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2010-03-07

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and three production wells. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide was injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide was injected to displace the oil bank to the production wells by water injection. By March 7,2010, 8,736 bbl of oil were produced from the pilot. Production from wells to the northwest of the pilot region indicates that oil displaced from carbon dioxide injection was produced from Colliver A7, Colliver A3, Colliver A14 and Graham A4 located on adjacent leases. About 19,166 bbl of incremental oil were estimated to have been produced from these wells as of March 7, 2010. There is evidence of a directional permeability trend toward the NW through the pilot region. The majority of the injected carbon dioxide remains in the pilot region, which has been maintained at a pressure at or above the minimum miscibility pressure. Estimated oil recovery attributed to the CO2 flood is 27,902 bbl which is equivalent to a gross CO2 utilization of 4.8 MCF/bbl. The pilot project is not economic.

  18. Kuiper Binary Object Formation

    CERN Document Server

    Nazzario, R C; Covington, C; Kagan, D; Hyde, T W

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction between the KBOs and the third body causes one of four effects; scattering into the Oort cloud, collisions with the growing protoplanets, formation of binary pairs, or creation of a single Kuiper belt object. Additionally, the initial location of the progenitors of the Kuiper belt objects also has a significant effect on binary formation.

  19. Kuiper Binary Object Formation

    OpenAIRE

    Nazzario, R. C.; Orr, K.; Covington, C.; Kagan, D.; Hyde, T. W.

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction betw...

  20. Eclipsing Binary Pulsars

    CERN Document Server

    Freire, P C C

    2004-01-01

    The first eclipsing binary pulsar, PSR B1957+20, was discovered in 1987. Since then, 13 other eclipsing low-mass binary pulsars have been found, 12 of these are in globular clusters. In this paper we list the known eclipsing binary pulsars and their properties, with special attention to the eclipsing systems in 47 Tuc. We find that there are two fundamentally different groups of eclipsing binary pulsars; separated by their companion masses. The less massive systems (M_c ~ 0.02 M_sun) are a product of predictable stellar evolution in binary pulsars. The systems with more massive companions (M_c ~ 0.2 M_sun) were formed by exchange encounters in globular clusters, and for that reason are exclusive to those environments. This class of systems can be used to learn about the neutron star recycling fraction in the globular clusters actively forming pulsars. We suggest that most of these binary systems are undetectable at radio wavelengths.

  1. Phenomenological gravitational waveforms from spinning coalescing binaries

    CERN Document Server

    Sturani, R; Cadonati, L; Guidi, G M; Healy, J; Shoemaker, D; Vicere', A

    2010-01-01

    An accurate knowledge of the coalescing binary gravitational waveform is crucial for match filtering techniques, which are currently used in the observational searches performed by the LIGO-Virgo collaboration. Following an earlier paper by the same authors we expose the construction of analytical phenomenological waveforms describing the signal sourced by generically spinning binary systems. The gap between the initial inspiral part of the waveform, described by spin-Taylor approximants, and its final ring-down part, described by damped exponentials, is bridged by a phenomenological phase calibrated by comparison with the dominant spherical harmonic mode of a set of waveforms including both numerical and phenomenological waveforms of a different type. All waveforms considered describe equal mass systems with dimension-less spin magnitudes equal to 0.6. The noise-weighted overlap integral between numerical and phenomenological waveforms ranges between 0.93 and 0.98 for a wide span of mass values.

  2. Glass transition in binary eutectic systems: best glass-forming composition.

    Science.gov (United States)

    Wang, Li-Min; Li, Zijing; Chen, Zeming; Zhao, Yue; Liu, Riping; Tian, Yongjun

    2010-09-23

    The glass transition and glass-forming ability in a binary eutectic system of methyl o-toluate (MOT) versus methyl p-toluate (MPT) are studied across the whole composition range. The phase diagram is constructed to explore the best glass-forming composition as the characteristic temperatures of the glass transition, crystallization, eutectic, and liquidus are determined. The best vitrification region is found to locate between the eutectic and the midpoint compositions of the eutectic line, indicating a remarkable deviation from the eutectic composition. The compilation of various simple binary eutectic systems covering inorganic, metallic, ionic, and molecular glass-forming liquids reproduces the rule. Kinetics and thermodynamics in binary systems are investigated to associate with the rule. The composition dependence of the structural relaxation time and the kinetic fragility are presented with dielectric measurements. It is found that whereas mixing of binary miscible liquids kinetically favors glass formation, thermodynamic contribution to the deviation of the best glass-forming composition from eutectics is implied.

  3. Binary Masking & Speech Intelligibility

    DEFF Research Database (Denmark)

    Boldt, Jesper

    The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime...... mask using a directional system and a method for correcting errors in the target binary mask. The last part of the thesis, proposes a new method for objective evaluation of speech intelligibility.......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...

  4. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  5. Binary Neutron Star Mergers

    Directory of Open Access Journals (Sweden)

    Joshua A. Faber

    2012-07-01

    Full Text Available We review the current status of studies of the coalescence of binary neutron star systems. We begin with a discussion of the formation channels of merging binaries and we discuss the most recent theoretical predictions for merger rates. Next, we turn to the quasi-equilibrium formalisms that are used to study binaries prior to the merger phase and to generate initial data for fully dynamical simulations. The quasi-equilibrium approximation has played a key role in developing our understanding of the physics of binary coalescence and, in particular, of the orbital instability processes that can drive binaries to merger at the end of their lifetimes. We then turn to the numerical techniques used in dynamical simulations, including relativistic formalisms, (magneto-hydrodynamics, gravitational-wave extraction techniques, and nuclear microphysics treatments. This is followed by a summary of the simulations performed across the field to date, including the most recent results from both fully relativistic and microphysically detailed simulations. Finally, we discuss the likely directions for the field as we transition from the first to the second generation of gravitational-wave interferometers and while supercomputers reach the petascale frontier.

  6. The miscibility of milk sphingomyelin and cholesterol is affected by temperature and surface pressure in mixed Langmuir monolayers.

    Science.gov (United States)

    Cheng, Ken; Ropers, Marie-Hélène; Lopez, Christelle

    2017-06-01

    The miscibility of milk sphingomyelin (milk-SM) and cholesterol was investigated in this study. The effect of different physical states of milk-SM on its interactions with cholesterol was determined by the recording of isotherms of compression of Langmuir films for temperatures above and below the gel to Lα phase transition of milk-SM (Tm∼34°C). For T=15°CTm, the milk-SM molecules were in a LE phase regardless of the surface pressure applied. A phase diagram pressure - milk-SM/cholesterol composition was established. This study demonstrated that both temperature and surface pressure affected the miscibility between the milk-SM and cholesterol. The strongest attractive forces (i.e. condensing effect) were identified for 30mol% cholesterol when the milk-SM was in the LE phase state.

  7. Solution of the Burger’s Equation for Longitudinal Dispersion Phenomena Occurring in Miscible Phase Flow through Porous Media

    Directory of Open Access Journals (Sweden)

    Monika N. Mehta

    2012-04-01

    Full Text Available An approximate solution of longitudinal dispersion phenomena occurring in two phase miscible fluid flow through porous media has been obtained by using the group theoretic approach. The longitudinal dispersion coefficient is assumed to be directly proportional to the concentration of the fluid for a distance x and at any time t > 0. The graphical representation for the concentration of the fluid for a distance x and at time t > 0 has been obtained using Mat lab coding.

  8. How bright are the gaps in circumbinary disk systems?

    CERN Document Server

    Shi, Ji-Ming

    2016-01-01

    When a circumbinary disk surrounds a binary whose secondary's mass is at least $\\sim 10^{-2}\\times$ the primary's mass, a nearly empty cavity with radius a few times the binary separation is carved out of the disk. Narrow streams of material pass from the inner edge of the circumbinary disk into the domain of the binary itself, where they eventually join onto the small disks orbiting the members of the binary. Using data from 3-d MHD simulations of this process, we determine the luminosity of these streams; it is mostly due to weak laminar shocks, and is in general only a few percent of the luminosity of adjacent regions of either the circumbinary disk or the "mini-disks". This luminosity therefore hardly affects the deficit in the thermal continuum predicted on the basis of a perfectly dark gap region.

  9. Binary and Millisecond Pulsars

    Directory of Open Access Journals (Sweden)

    Lorimer Duncan R.

    2008-11-01

    Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M_⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44 orbit around an unevolved companion.

  10. Binary Popldation Synthcsis Study

    Institute of Scientific and Technical Information of China (English)

    HAN Zhanwen

    2011-01-01

    Binary population synthesis (BPS), an approach to evolving millions of stars (including binaries) simultaneously, plays a crucial role in our understanding of stellar physics, the structure and evolution of galaxies, and cosmology. We proposed and developed a BPS approach, and used it to investigate the formation of many peculiar stars such as hot subdwarf stars, progenitors of type la supernovae, barium stars, CH stars, planetary nebulae, double white dwarfs, blue stragglers, contact binaries, etc. We also established an evolution population synthesis (EPS) model, the Yunnan Model, which takes into account binary interactions for the first time. We applied our model for the origin of hot subdwarf stars in the study of elliptical galaxies and explained their far-UV radiation.

  11. Investigation and correlation of drug polymer miscibility and molecular interactions by various approaches for the preparation of amorphous solid dispersions.

    Science.gov (United States)

    Meng, Fan; Trivino, Anne; Prasad, Dev; Chauhan, Harsh

    2015-04-25

    Curcumin (CUR) was used as a poorly soluble drug whereas polyvinyl pyrrolidone K90 (PVP), Eudragit EPO (EPO), hydroxypropyl methylcellulose E5 (HPMC) and polyethylene glycol 8000 (PEG) were used as hydrophilic polymers. CUR polymer miscibility was evaluated by solubility parameter, melting point depression and glass transition temperature (Tg) measurements. Molecular interactions between CUR and polymers were determined by Fourier-transform infrared spectroscopy (FTIR) and Raman. Amorphous solid dispersions were prepared with CUR-polymer ratio of 70:30 (w/w) by solvent evaporation technique and were evaluated for dissolution enhancement using USP II method. Physical states of solid dispersions were characterized by X-ray diffraction (XRD) whereas thermal behaviors were investigated using modulated differential scanning calorimetry (MDSC). CUR-EPO system showed good miscibility through all the approaches, whereas immiscibility was found in other CUR-polymer systems. CUR-EPO and CUR-HPMC systems showed significant molecular interactions whereas CUR-PVP and CUR-PEG showed no molecular interactions. All solid dispersions showed significant dissolution enhancement with CUR-EPO showing highest dissolution rate during first 1h whereas CUR-HPMC was effective in maintaining high CUR concentrations for 6h. The study highlights the importance of investigating and correlating drug polymer miscibility and molecular interactions by various approaches for successful formulation of amorphous solid dispersions.

  12. Towards smaller gap microbulks

    CERN Document Server

    Attié, D.; Dafni, T; Ferrer-Ribas, E.; Ferrer-Ribas, E; Ferry, S; Giomataris, Y; Herrera, D C; Iguaz, F J; Irastorza, I G; Kebbiri, M; Papaevangelou, T; de Oliveira, R; Seguí, L; Tomás, A

    2014-01-01

    Small gap Micromegas detectors ( < 50 μm) are expected to be optimal for high pressure applications. Combining the microbulk manufacturing technique with a small gap can result in attractive detectors for rare event detection, in particular double beta decay or dark matter searches. We present novel results obtained with small gap microbulks (25 and 12.5 μm) that have been manufactured recently. For the first time for this type of detectors, we show experimentally that for each amplification gap there is an optimal pressure and that smaller gaps are more suitable for higher pressures.

  13. Antiwear performance and mechanism of an oil-miscible ionic liquid as a lubricant additive.

    Science.gov (United States)

    Qu, Jun; Bansal, Dinesh G; Yu, Bo; Howe, Jane Y; Luo, Huimin; Dai, Sheng; Li, Huaqing; Blau, Peter J; Bunting, Bruce G; Mordukhovich, Gregory; Smolenski, Donald J

    2012-02-01

    An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential antiwear lubricant additive. Unlike most other ILs that have very low solubility in nonpolar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347 °C, showed no corrosive attack to cast iron in an ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron lubricating oils. For example, a 5 wt % addition into a synthetic base oil eliminated the scuffing failure experienced in neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by 3 orders of magnitude. A synergistic effect on wear protection was observed with the current antiwear additive when added into a fully formulated engine oil. Nanostructure examination and composition analysis revealed a tribo-boundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the IL's antiscuffing and antiwear functionality.

  14. Study of rheological behavior and miscibility of epoxidized natural rubber modified neoprene

    Science.gov (United States)

    Chiu, Hsien-Tang; Tsai, Peir-An; Cheng, Tzu-Chi

    2006-02-01

    The Mooney viscosity, curing rates, vulcanization behavior, and the relationship between molecular motion of epoxidized natural rubber (ENR) and neoprene (CR) blends at different blending ratios have been studied. The experimental results of ENR/CR blends show that the Mooney viscosity decreased gradually. Plasticization was most pronounced at an ENR/CR ratio of 75/25 and is thus the easiest to process. Owing to the ring opening of the epoxy group of ENR, the rate of crosslink formation is much faster than that of CR at higher temperature. The vulcanized rate increased with increasing ENR content. The results indicated that 175 °C and 5 min were the optimum processing conditions for ENR/CR blends. The DMA spectra showed a single damping peak for the ENR/CR blends, which suggests that ENR and CR are miscible. As seen in the Arrhenius plot of frequency against T g, the activation energy increased with increasing ENR contents. This suggests the existence of interpenetration of these two rubber molecular networks.

  15. Scale-up of miscible flood processes. Quarterly report, July 1, 1993--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Orr, F.M. Jr.

    1993-12-31

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Compositional and first-contact miscible simulations of viscous fingering and gravity segregation are compared to show that the two techniques can give very different results. Also, analyzed are two-dimensional and three-dimensional flows in which gravity segregation and viscous fingering interact. The simulations show that 2D and 3D flows can differ significantly. A comparison of analytical solutions for three-component two-phase flow with experimental results for oil/water/alcohol systems is reported. While the experiments and theory show reasonable agreement, some differences remain to be explained. The scaling behavior of the interaction of gravity segregation and capillary forces is investigated through simulations and through scaling arguments based on analysis of the differential equations. The simulations show that standard approaches do not agree well with results of low IFT displacements. The scaling analyses, however, reveal flow regimes where capillary, gravity, or viscous forces dominate the flow.

  16. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  17. Influence of rheology on buoyancy driven instabilities of miscible displacements in 2D micromodels

    Science.gov (United States)

    D'Angelo, M. V.; Auradou, H.; Rosen, M.; Hulin, J. P.

    2009-05-01

    The stability of miscible displacements of Newtonian and shear-thinning fluids of slightly different densities (Δρ/ρ approx 3× 10-4) with a mean flow velocity U is investigated in a 2D transparent network of channels (average width = 0.33 mm). Concentration maps providing information at both the global and local scale are obtained through optical absorption measurements and compared in gravitationally stable and unstable vertical flow configurations; the influence of buoyant flows of typical velocity Ug is characterized by the gravity number Ng = Ug/|U|. For Ng glycerol solution, ld is only the same in the stable and unstable configurations for |Ng| 0.2, front spreading is not diffusive any more. In the stable configuration, in contrast, the front is flattened by buoyancy for Ng solution, both the concentration maps and the value of ld are the same in the stable and unstable configurations over the full range of U values investigated: this stabilization is explained by their high effective viscosity at low shear rates keeping Ng below the instability threshold even at the lowest velocities.

  18. Three-dimensional miscible displacement simulations in homogeneous porous media with gravity override

    Science.gov (United States)

    Riaz, A.; Meiburg, E.

    2003-11-01

    High-accuracy three-dimensional numerical simulations of miscible displacements with gravity override in homogeneous porous media are carried out for the quarter five-spot configuration. Special emphasis is placed on describing the influence of viscous and gravitational effects on the overall displacement dynamics in terms of the vorticity variable. Even for neutrally buoyant displacements, three-dimensional effects are seen to change the character of the flow significantly, in contrast to earlier findings for rectilinear displacements. At least in part this can be attributed to the time dependence of the most dangerous vertical instability mode. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Péclet number is enhanced owing to the higher flow rate. However, buoyancy forces of a certain magnitude can lead to a pinch-off of the gravity layer, thereby slowing it down. Overall, an increase of the gravitational parameter is found to enhance mostly the vertical perturbations, while larger Pe values act towards amplifying horizontal disturbances. The asymptotic rate of growth of the mixing length varies only with Péclet number. For large Péclet numbers, an asymptotic value of 0.7 is observed. A scaling law for the thickness of the gravity layer is obtained as well. In contrast to immiscible flow displacements, it is found to increase with the gravity parameter.

  19. Miscible porous media displacements driven by non-vertical injection wells

    Science.gov (United States)

    Upchurch, E.; Meiburg, E.

    High-resolution simulations are employed to identify and analyse the mechanisms dominating miscible porous media displacements generated by inclined injection wells. Compared to vertical injection wells, significant differences are observed that strongly influence breakthrough times and recovery rates. Constant density and viscosity displacements, for which the velocity field is potential in nature, demonstrate the existence of pronounced flow non-uniformities, due to the interaction of the inclined well with the reservoir boundaries. These non-uniformities deform the fronts during the initial displacement stages.In the presence of a viscosity difference, the non-uniformities of the potential flow field result in a focusing of the fingering instability. If the fluids also have different densities, a gravity tongue will reinforce the dominant finger along one front, while a gravitational instability leads to the disintegration of the dominant finger along the other front. Hence, the two fronts emerging from the inclined injection well usually evolve very differently from each other for variable density and viscosity displacements.For inclined injection wells and sufficiently large mobility ratios, gravity tongues are seen to evolve dendritically for an intermediate range of density contrasts. While mild gravitational forces are necessary to create the gravity tongue in the first place, large density differences will suppress the growth of the dendritic side branches. Since the dendritic branches appear along the side of the gravity tongue that should be stable according to traditional stability criteria, it can be concluded that the tip region plays a crucial role in their formation.

  20. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Science.gov (United States)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB-4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible.

  1. Fluid flow behaviour of gas-condensate and near-miscible fluids at the pore scale

    Energy Technology Data Exchange (ETDEWEB)

    Dawe, Richard A. [Department of Chemical Engineering, University of West Indies, St. Augustine (Trinidad and Tobago); Grattoni, Carlos A. [Department of Earth Science and Engineering, Imperial College, London, SW7 2BP (United Kingdom)

    2007-02-15

    Retrograde condensate reservoir behaviour is complex with much of the detailed mechanisms of the multiphase fluid transport and mass transfer between the phases within the porous matrix still speculative. Visual modelling of selected processes occurring at the pore level under known and controlled boundary conditions can give an insight to fluid displacements at the core scale and help the interpretation of production behaviour at reservoir scale. Visualisation of the pore scale two-phase flow mechanisms has been studied experimentally at low interfacial tensions, < 0.5 mN/m, using a partially miscible fluid system in glass visual micro models. As the interfacial tension decreases the balance between fluid-fluid forces (interfacial, spreading and viscous) and fluid-solid interactions (wettability and viscous interactions) changes. Data measurements in the laboratory, particularly relative permeability, will therefore always be difficult especially for condensate fluids just below their dew point. What is certain is that gas production from a gas-condensate leads to condensate dropout when pressure falls below the dew point, either within the wellbore or, more importantly, in the reservoir. This paper illustrates some pore scale physics, particularly interfacial phenomena at low interfacial tension, which has relevance to appreciating the flow of condensate fluids close to their dew point either near the wellbore (which affects well productivity) or deep inside the reservoir (which affects condensate recovery). (author)

  2. Miscible experiments on the Rayleigh-Taylor instability using planar laser induced fluorescence visualization

    Science.gov (United States)

    Mokler, Matthew; Roberts, Michael; Jacobs, Jeffrey

    2011-11-01

    Incompressible Rayleigh-Taylor instability experiments are presented in which two stratified miscible liquids having Atwood number of 0.2 are accelerated in a vertical linear induction motor driven drop tower. A test sled having only vertical freedom of motion contains the experiment tank and visualization equipment. The sled is positioned at the top of the tower within the linear motors and accelerated downward causing the initially stable interface to be unstable and allowing the Rayleigh-Taylor instability to develop. Experiments are presented with and without forced initial perturbations produced by vertically oscillating the test sled prior to the start of acceleration. The interface is visualized using a 445nm laser light source that illuminates a fluorescent dye mixed in one of the fluids. The resulting fluorescent images are recorded using a monochromatic high speed video camera. The laser beam is synchronously swept across the fluorescent fluid, at the frame rate of the camera, exposing a single plane of the interface allowing for the measurement of spike and bubble mixing layer growth rates.

  3. Miscible and immiscible liquid experiments and simulations on the Rayleigh-Taylor instability

    Science.gov (United States)

    Roberts, Michael; Mokler, Matthew; Cabot, William; Jacobs, Jeffrey

    2011-11-01

    Experiments and numerical simulations are presented in which an incompressible system of two liquids is accelerated to produce the Rayleigh-Taylor instability. In these experiments, the initially stable, stratified liquid combination is accelerated downward on a vertical rail system in one of two experimental apparatuses: an apparatus in which a system of weights and pulleys accelerates the liquid filled tank (which is affixed to a test sled), or a new apparatus which uses linear induction motors to accelerate the tank (which is attached to an aluminum plate) to produce much greater acceleration levels. Both miscible and immiscible liquid combinations are used. In both apparatuses the resulting fluid flows are visualized with backlit imaging using LED backlights in conjunction with monochrome high-speed video cameras, both of which travel with the moving fluid filled containers. Initial perturbations are either unforced and allowed to progress from background noise or forced by vertically oscillating the liquid combination to produce parametric internal waves. The results of these experiments are compared to numerical simulations performed using the CFD code Miranda.

  4. NOAA Climate Data Record (CDR) of Zonal Mean Ozone Binary Database of Profiles (BDBP), version 1.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) of Zonal Mean Ozone Binary Database of Profiles (BDBP) dataset is a vertically resolved, global, gap-free and zonal mean dataset...

  5. Eclipsing Binary Update, No. 2.

    Science.gov (United States)

    Williams, D. B.

    1996-01-01

    Contents: 1. Wrong again! The elusive period of DHK 41. 2. Stars observed and not observed. 3. Eclipsing binary chart information. 4. Eclipsing binary news and notes. 5. A note on SS Arietis. 6. Featured star: TX Ursae Majoris.

  6. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter

    2008-01-01

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  7. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Rune Hansen, Esben; Srinivasa Rao, S.; Tiedemann, Peter

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  8. Orbits for sixteen binaries

    Directory of Open Access Journals (Sweden)

    Cvetković Z.

    2006-01-01

    Full Text Available In this paper orbits for 13 binaries are recalculated and presented. The reason is that recent observations show higher residuals than the corresponding ephemerides calculated by using the orbital elements given in the Sixth Catalog of Orbits of Visual Binary Stars. The binaries studied were: WDS 00182+7257 = A 803, WDS 00335+4006 = HO 3, WDS 00583+2124 = BU 302, WDS 01011+6022 = A 926, WDS 01014+1155 = BU 867, WDS 01112+4113 = A 655, WDS 01361−2954 + HJ 3447, WDS 02333+5219 = STT 42 AB,WDS 04362+0814 = A 1840 AB,WDS 08017−0836 = A 1580, WDS 08277−0425 = A 550, WDS 17471+1742 = STF 2215 and WDS 18025+4414 = BU 1127 Aa-B. In addition, for three binaries - WDS 01532+1526 = BU 260, WDS 02563+7253 = STF 312 AB and WDS 05003+3924 = STT 92 AB - the orbital elements are calculated for the first time. In this paper the authors present not only the orbital elements, but the masses dynamical parallaxes, absolute magnitudes and ephemerides for the next five years, as well.

  9. Equational binary decision diagrams

    NARCIS (Netherlands)

    Groote, J.F.; Pol, J.C. van de

    2000-01-01

    We incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and tautology checkin

  10. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  11. MONOMOLECULAR FILMS OF COPOLYMERS OF OXYETHYLENE AND OXYPROPYLENE,POLYPROPYLENE GLYCOL AND THEIR BINARY MIXTURES

    Institute of Scientific and Technical Information of China (English)

    LI Wailang; DING Faxiang; GU Tiren

    1989-01-01

    The behaviour of monolayers of copolymers of oxyethylene and oxypropylene (UH29 and UH68),polypropylene glycol (UHPPG) and their binary mixtures on air-water interface has been investigated carefully on compression -expansion cycles. The first compression isotherm is approximately an equilibrium one. In the UHPPG-UH29 and UHPPG -UH68 systems, the calculated average π-a curves based on simple additivity ofthe two individual components coincide with the experimental results reasonably well. It is suggested that the two components are miscible and form near- ideal solution at the air- water interface.The compression- expansion cycle experiments shows some degree of hysteresis. The order of degree of hysteresis for individual components is UH68 > UH29 > UHPPG. The explanation for the hysteresis is proposed.

  12. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  13. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  14. Search of sub-parsec massive binary black holes through line diagnosis II

    CERN Document Server

    Montuori, C; Haardt, F; Colpi, M; Decarli, R

    2012-01-01

    Massive black hole binaries at sub-parsec separations may display in their spectra anomalously small flux ratios between the MgII and CIV broad emission lines, i.e. F_MgII/F_CIV <~ 0.1, due to the erosion of the broad line region around the active, secondary black hole, by the tidal field of the primary. In Paper I by Montuori et al. (2011), we focussed on broad lines emitted by gas bound to the lighter accreting member of a binary when the binary is at the center of a hollow density region (the gap) inside a circum-binary disc. The main aim of this new study is at exploring the potential contribution to the broad line emission by the circum-binary disc and by gaseous streams flowing toward the black hole through the gap. We carry out a post-process analysis of data extracted from a SPH simulation of a circum-binary disc around a black hole binary. Our main result is that the MgII to CIV flux ratio can be reduced to ~ 0.1 within an interval of sub-pc binary separations of the order of a ~ (0.01-0.2)(f_Edd/...

  15. Miscibility behavior and formation mechanism of stabilized felodipine-polyvinylpyrrolidone amorphous solid dispersions.

    Science.gov (United States)

    Karavas, Evangelos; Ktistis, Georgios; Xenakis, Aristotelis; Georgarakis, Emmanouel

    2005-07-01

    In the present study, solid dispersion systems of felodipine (FEL) with polyvinylpyrrolidone (PVP) were developed, in order to enhance solid state stability and release kinetics. The prepared systems were characterized by using Differential Scanning Calorimetry, X-Ray Diffraction, and Scanning Electron Microscopy techniques, while the interactions which take place were identified by using Fourier Transformation-Infrared Spectroscopy. Due to the formation of hydrogen bonds between the carbonyl group of PVP and the amino groups of FEL, transition of FEL from crystalline to amorphous state was achieved. The dispersion of FEL was found to be in nano-scale particle sizes and dependent on the FEL/PVP ratio. This modification leads to partial miscibility of the two components, as it was verified by DSC and optimal glass dispersion of FEL into the polymer matrix since no crystalline structure was detected with XRD. The above deformation has a significant effect on the dissolution enhancement and the release kinetics of FEL, as it causes the pattern to change from linear to logarithmic. An impressive optimization of the dissolution profile is observed corresponding to a rapid release of FEL in the system containing 10% w/w of FEL, releasing 100% in approximately 20 min. The particle size of dispersed FEL into PVP matrix could be classified as the main parameter affecting dissolution optimization. The mechanism of such enhancement consists of the lower energy required for the dissolution due to the amorphous transition and the fine dispersion, which leads to an optimal contact surface of the drug substance with the dissolution media. The prepared systems are stable during storage at 40 +/- 1 degrees C and relative humidity of 75 +/- 5%. Addition of sodium docusate as surfactant does not affect the release kinetics, but only the initial burst due to its effect on the surface tension and wettability of the systems.

  16. Morphological transformations in polymer brushes in binary mixtures: DPD study.

    Science.gov (United States)

    Cheng, Jianli; Vishnyakov, Aleksey; Neimark, Alexander V

    2014-11-04

    Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

  17. The Binary Garrote

    CERN Document Server

    Kappen, H J

    2011-01-01

    In this paper, I present a new model and solution method for sparse regression. The model introduces binary selector variables $s_i$ for the features $i$ in a way that is similar to Breiman's Garrote model. I refer to this method as the binary Garrote (BG). The posterior probability for $s_i$ is computed in the variational approximation. The BG is compared numerically with the Lasso method and with ridge regression. Numerical results on synthetic data show that the BG yields more accurate predictions and more accurately reconstructs the true model than the other methods. The naive implementation of the BG requires the inversion of a modified covariance matrix which scales cubic in the number of features. We indicate how for sparse problem the solution can be computed linear in the number of features.

  18. Binary Tetrahedral Flavor Symmetry

    CERN Document Server

    Eby, David A

    2013-01-01

    A study of the T' Model and its variants utilizing Binary Tetrahedral Flavor Symmetry. We begin with a description of the historical context and motivations for this theory, together with some conceptual background for added clarity, and an account of our theory's inception in previous works. Our model endeavors to bridge two categories of particles, leptons and quarks, a unification made possible by the inclusion of additional Higgs particles, shared between the two fermion sectors and creating a single coherent system. This is achieved through the use of the Binary Tetrahedral symmetry group and an investigation of the Tribimaximal symmetry evidenced by neutrinos. Our work details perturbations and extensions of this T' Model as we apply our framework to neutrino mixing, quark mixing, unification, and dark matter. Where possible, we evaluate model predictions against experimental results and find excellent matching with the atmospheric and reactor neutrino mixing angles, an accurate prediction of the Cabibb...

  19. Binary Love Relations

    CERN Document Server

    Yagi, Kent

    2015-01-01

    When in a tight binary, the mutual tidal deformations of neutron stars imprint onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the gravitational wave model. We here resolve this problem by discovering approximately universal relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the gravitational wave model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between equation-of-state models, and improve tests of General Relativity and cosmology.

  20. Binary Love relations

    Science.gov (United States)

    Yagi, Kent; Yunes, Nicolás

    2016-07-01

    When in a tight binary, the mutual tidal deformations of neutron stars get imprinted onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave (GW) observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the GW model. We here resolve this problem by discovering approximately equation-of-state (EoS)-insensitive relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the GW model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between EoS models, and improve tests of general relativity and cosmology.

  1. Comparative studies of empirical correlations for calculation of minimum miscibility pressure; Estudo comparativo de correlacoes empiricas para o calculo da pressao minima de miscibilidade

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, P.S. [PETROBRAS, Salvador, BA (Brazil). Unidade de Negocios da Bahia]. E-mail: psrocha@petrobras.com.br; Meirelles, C.P.; Santos, R.B.; Costa, G.M.N. [Universidade Salvador (UNIFACS), Salvador, BA (Brazil). Centro de Estudos em Petroleo e Gas Natural (CEPGN)]. E-mail: gloria.costa@unifacs.br

    2003-07-01

    The miscible recovery of oil can be obtained by displacing it using CO{sub 2} at a pressure greater than a minimum level, called minimum miscibility pressure. In this study we used three correlations for the calculation of the minimum miscibility pressure in multiple contact: Yellig and Metcalfe method; Alston, Kokolis and James method; and Enick, Holden and Morsi method. For a carefully evaluation of the range of application and restrictions, a data base from the literature containing 125 combinations of oils, temperatures and solvents, for which the minimum miscibility pressures were available using pure or impure CO{sub 2} from experiments in slim tube apparatus. This study revealed that the best method is the Alston, Kokolis and James one, although the average relative error and the standard deviation are greater than the values cited by the authors. An evaluation of the correlation coefficient revealed that the number of independent variables in each method is insufficient. Although the second and third methods consider the impurities in the CO{sub 2}, the error obtained in the calculation of the minimum miscibility pressure using pure CO{sub 2} is lower than the one for impure CO{sub 2}, showing that the effects of the contaminants are not well described by the correlations as the authors say. (author)

  2. Bridging a Cultural Gap

    Science.gov (United States)

    Leviatan, Talma

    2008-01-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

  3. Live cell plasma membranes do not exhibit a miscibility phase transition over a wide range of temperatures.

    Science.gov (United States)

    Lee, Il-Hyung; Saha, Suvrajit; Polley, Anirban; Huang, Hector; Mayor, Satyajit; Rao, Madan; Groves, Jay T

    2015-03-26

    Lipid/cholesterol mixtures derived from cell membranes as well as their synthetic reconstitutions exhibit well-defined miscibility phase transitions and critical phenomena near physiological temperatures. This suggests that lipid/cholesterol-mediated phase separation plays a role in the organization of live cell membranes. However, macroscopic lipid-phase separation is not generally observed in cell membranes, and the degree to which properties of isolated lipid mixtures are preserved in the cell membrane remain unknown. A fundamental property of phase transitions is that the variation of tagged particle diffusion with temperature exhibits an abrupt change as the system passes through the transition, even when the two phases are distributed in a nanometer-scale emulsion. We support this using a variety of Monte Carlo and atomistic simulations on model lipid membrane systems. However, temperature-dependent fluorescence correlation spectroscopy of labeled lipids and membrane-anchored proteins in live cell membranes shows a consistently smooth increase in the diffusion coefficient as a function of temperature. We find no evidence of a discrete miscibility phase transition throughout a wide range of temperatures: 14-37 °C. This contrasts the behavior of giant plasma membrane vesicles (GPMVs) blebbed from the same cells, which do exhibit phase transitions and macroscopic phase separation. Fluorescence lifetime analysis of a DiI probe in both cases reveals a significant environmental difference between the live cell and the GPMV. Taken together, these data suggest the live cell membrane may avoid the miscibility phase transition inherent to its lipid constituents by actively regulating physical parameters, such as tension, in the membrane.

  4. Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

    KAUST Repository

    Kou, Jisheng

    2016-05-10

    In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng-Robinson equation of state). Because of partial miscibility, thermodynamic relations are used to model not only interfacial properties but also bulk properties, including density, composition, pressure, and realistic viscosity. As far as we know, this effort is the first time to use diffuse interface modeling based on equation of state for modeling of multi-component two-phase flow with partial miscibility. In numerical simulation, the key issue is to resolve the high contrast of scales from the microscopic interface composition to macroscale bulk fluid motion since the interface has a nanoscale thickness only. To efficiently solve this challenging problem, we develop a multi-scale simulation method. At the microscopic scale, we deduce a reduced interfacial equation under reasonable assumptions, and then we propose a formulation of capillary pressure, which is consistent with macroscale flow equations. Moreover, we show that Young-Laplace equation is an approximation of this capillarity formulation, and this formulation is also consistent with the concept of Tolman length, which is a correction of Young-Laplace equation. At the macroscopical scale, the interfaces are treated as discontinuous surfaces separating two phases of fluids. Our approach differs from conventional sharp-interface two-phase flow model in that we use the capillary pressure directly instead of a combination of surface tension and Young-Laplace equation because capillarity can be calculated from our proposed capillarity formulation. A compatible condition is also derived for the pressure in flow equations. Furthermore, based on the proposed capillarity formulation, we design an efficient numerical method for directly computing the capillary pressure between two fluids composed of multiple components. Finally, numerical tests

  5. Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

    Science.gov (United States)

    Kou, Jisheng; Sun, Shuyu

    2016-08-01

    In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng-Robinson equation of state). Because of partial miscibility, thermodynamic relations are used to model not only interfacial properties but also bulk properties, including density, composition, pressure, and realistic viscosity. As far as we know, this effort is the first time to use diffuse interface modeling based on equation of state for modeling of multi-component two-phase flow with partial miscibility. In numerical simulation, the key issue is to resolve the high contrast of scales from the microscopic interface composition to macroscale bulk fluid motion since the interface has a nanoscale thickness only. To efficiently solve this challenging problem, we develop a multi-scale simulation method. At the microscopic scale, we deduce a reduced interfacial equation under reasonable assumptions, and then we propose a formulation of capillary pressure, which is consistent with macroscale flow equations. Moreover, we show that Young-Laplace equation is an approximation of this capillarity formulation, and this formulation is also consistent with the concept of Tolman length, which is a correction of Young-Laplace equation. At the macroscopical scale, the interfaces are treated as discontinuous surfaces separating two phases of fluids. Our approach differs from conventional sharp-interface two-phase flow model in that we use the capillary pressure directly instead of a combination of surface tension and Young-Laplace equation because capillarity can be calculated from our proposed capillarity formulation. A compatible condition is also derived for the pressure in flow equations. Furthermore, based on the proposed capillarity formulation, we design an efficient numerical method for directly computing the capillary pressure between two fluids composed of multiple components. Finally, numerical tests

  6. Binary-Signal Recovery

    Science.gov (United States)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  7. Massive Black Hole Binary Evolution

    Directory of Open Access Journals (Sweden)

    Merritt David

    2005-11-01

    Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

  8. Superconvergence of a Combined Mixed Finite Element and Discontinuous Galerkin Method for a Compressible Miscible Displacement Problem

    Institute of Scientific and Technical Information of China (English)

    Ji-ming Yang; Yanping Chen

    2011-01-01

    A combined mixed finite element and discontinuous Galerkin method for a compressible miscible displacement problem which includes molecular diffusion and dispersion in porous media is investigated. That is to say, the mixed finite element method with Raviart-Thomas space is applied to the flow equation, and the transport one is solved by the symmetric interior penalty discontinuous Galerkin (SIPG) approximation. Based on projection interpolations and induction hypotheses, a superconvergence estimate is obtained. During the analysis, an extension of the Darcy velocity along the Gauss line is also used in the evaluation of the coefficients in the Galerkin procedure for the concentration.

  9. Relative role of convective and diffusive mixing in the miscible Rayleigh-Taylor instability in porous media

    Science.gov (United States)

    Gopalakrishnan, S. S.; Carballido-Landeira, J.; De Wit, A.; Knaepen, B.

    2017-01-01

    The relative role of convection and diffusion is characterized both numerically and experimentally for porous media flows due to a Rayleigh-Taylor instability of a horizontal interface between two miscible solutions in the gravity field. We show that, though globally convection dominates over diffusion during the nonlinear regime, diffusion can locally be as important as convection and even dominates over lateral convection far away from the fingertips. Our experimental and numerical computations of the temporal evolution of the mixing length, the width of the fingers, and their wavelength are in good agreement and show that the lateral evolution of fingers is governed by diffusion.

  10. Modified Method of Characteristics Combined with Finite Volume Element Methods for Incompressible Miscible Displacement Problems in Porous Media

    Directory of Open Access Journals (Sweden)

    Sarvesh Kumar

    2014-01-01

    Full Text Available The incompressible miscible displacement problem in porous media is modeled by a coupled system of two nonlinear partial differential equations, the pressure-velocity equation and the concentration equation. In this paper, we present a mixed finite volume element method (FVEM for the approximation of the pressure-velocity equation. Since modified method of characteristics (MMOC minimizes the grid orientation effect, for the approximation of the concentration equation, we apply a standard FVEM combined with MMOC. A priori error estimates in L∞(L2 norm are derived for velocity, pressure and concentration. Numerical results are presented to substantiate the validity of the theoretical results.

  11. Visual binary stars: data to investigate formation of binaries

    Science.gov (United States)

    Kovaleva,, D.; Malkov,, O.; Yungelson, L.; Chulkov, D.

    Statistics of orbital parameters of binary stars as well as statistics of their physical characteristics bear traces of star formation history. However, statistical investigations of binaries are complicated by incomplete or missing observational data and by a number of observational selection effects. Visual binaries are the most common type of observed binary stars, with the number of pairs exceeding 130 000. The most complete list of presently known visual binary stars was compiled by cross-matching objects and combining data of the three largest catalogues of visual binaries. This list was supplemented by the data on parallaxes, multicolor photometry, and spectral characteristics taken from other catalogues. This allowed us to compensate partly for the lack of observational data for these objects. The combined data allowed us to check the validity of observational values and to investigate statistics of the orbital and physical parameters of visual binaries. Corrections for incompleteness of observational data are discussed. The datasets obtained, together with modern distributions of binary parameters, will be used to reconstruct the initial distributions and parameters of the function of star formation for binary systems.

  12. Controlling the Melt Resistance to Flow as a Possibility of Improving the Miscibility and the Time Behavior of Some Blends Based on Starch

    Directory of Open Access Journals (Sweden)

    Doina Dimonie

    2015-01-01

    Full Text Available The paper proves that the miscibility of some blends based on starch can be improved by finding for each of them the melt resistance to flow at which the nonstationary flow and the melt degradation are avoided and the developed shear rate homogenizes optimally the material composition. The obtained results show that, for process sensitive materials like starches, the border between good and less miscibility is so narrow that the window of melt processing conditions and the best formulation must be found for each of them. The improving of miscibility by controlling the melt resistance to flow proves to be a good method to prevent retrogradation and plasticizer leaching and so to handle the new compounds behavior during usage.

  13. Prediction of Instability for Miscible Displacements in a Hele-Shaw Cell Prévision de l'instabilité pour des déplacements miscibles dans une cellule Hele-Shaw

    Directory of Open Access Journals (Sweden)

    Coskuner G.

    2006-11-01

    Full Text Available A universal dimensionless scaling group and its critical value at the onset of instability for a miscible displacement in a Hele-Shaw cell is derived. The derivation is based on a variational technique and it is capable of considering, for the first time, the effect of the length of a Hele-Shaw cell on the criterion for the onset of instability. The theory is verified by comparing it with forty-four Hele-Shaw cell experiments. On calcule un groupe universel sans dimension de mise à l'échelle et sa valeur critique au départ de l'instabilité dans un déplacement miscible dans une cellule Hele-Shaw. Ce calcul est basé sur une technique variationnelle et permet, pour la première fois, de prendre en compte l'effet de la longueur d'une cellule Hele-Shaw sur le critère d'apparition d'instabilité. La théorie est vérifiée en la comparant avec des expériences réalisées avec quarante-quatre cellules Hele-Shaw.

  14. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

    2007-10-15

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular

  15. Filling the Income Gap

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Income distribution has become one of the people's main concerns in China where more than 30years of reform and opening up have also resulted in an ever-expanding wealth gap.But narrowing down the rich-poor disparity will prove to be no easy task.Wei Zhong,a researcher with the Institute of Economics under the Chinese Academy of Social Sciences,elaborated on the origins and trends of China's widening income gap,and discussed solutions to curb the gap,in a recent article.Edited excerpts follow:

  16. Small-Gap Flows

    Science.gov (United States)

    1984-04-01

    34’OF CALIFORNIA# BERKELEY, CA 5.1720 ft (45 642-141 SMALL- GAP FLOWS BY E. 0. TUCK REPORT No. NAUE 84-1 CONTRACT N00014-84-K-OU26 APRIL i984...Mechanics, 41 (1970) 769-792. 11 3. Shallow-Water Waves at Discontinuities Shallow-water waves represent perhaps the prototype small- gap flow , the...solving (4.4) we need "initial" conditions at the starting station z = 0, and "exit" conditions at the station z = L where the gap flow merges with the

  17. Modelling Gender Pay Gaps

    OpenAIRE

    2004-01-01

    EXECUTIVE SUMMARYIntroductionThere has been little change in the full-time gender pay gap since the mid 1990s andin the female part-time/male full-time pay gap since the mid 1970s. The gender gapin hourly earnings for those employed full-time in Britain in 2003 was 18 per cent,while that between women working part-time and men working full-time was 40 percent.This research uses statistical methods to identify how much of the gender pay gap isassociated with different factors. The data set ana...

  18. Near-Infrared Polarimetry of the GG Tauri A Binary System

    CERN Document Server

    Itoh, Yoichi; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D; Carson, Joseph C; Egner, Sebastian; Feldt, Markus; Grady, Carol A; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S; Henning, Thomas; Hodapp, Klaus W; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R; Kuzuhara, Masayuki; Kwon, Jungmi; Matsuo, Taro; McElwain, Michael W; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro H; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Tomono, Daigo; Turner, Edwin L; Watanabe, Makoto; Wisniewski, John; Yamada, Toru; Mayama, Satoshi; Currie, Thayne; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide

    2015-01-01

    A high angular resolution near-infrared polarized-intensity image of the GG Tau A binary system was obtained with the Subaru Telescope. The image shows the circumbinary disk scattering the light from the central binary. The azimuthal profile of the polarized intensity of the circumbinary disk is roughly reproduced by a simple disk model with the Henyey-Greenstein function and the Rayleigh function, indicating small dust grains at the surface of the disk. Combined with a previous observation of the circumbinary disk, our image indicates that the gap structure in the circumbinary disk orbits anti-clockwise, while material in the disk orbit clockwise. We propose a shadow of material located between the central binary and the circumbinary disk. The separations and position angles of the stellar components of the binary in the past 20 years are consistent with the binary orbit with a = 33.4 AU and e = 0.34.

  19. Rotational mixing in close binaries

    CERN Document Server

    de Mink, S E; Langer, N; Yoon, S -Ch; Brott, I; Glebbeek, E; Verkoulen, M; Pols, O R

    2008-01-01

    Rotational mixing is a very important but uncertain process in the evolution of massive stars. We propose to use close binaries to test its efficiency. Based on rotating single stellar models we predict nitrogen surface enhancements for tidally locked binaries. Furthermore we demonstrate the possibility of a new evolutionary scenario for very massive (M > 40 solar mass) close (P < 3 days) binaries: Case M, in which mixing is so efficient that the stars evolve quasi-chemically homogeneously, stay compact and avoid any Roche-lobe overflow, leading to very close (double) WR binaries.

  20. Evolution of Close Binary Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  1. Chaos in Binary Category Computation

    CERN Document Server

    Gonçalves, Carlos Pedro

    2010-01-01

    Category computation theory deals with a web-based systemic processing that underlies the morphic webs, which constitute the basis of categorial logical calculus. It is proven that, for these structures, algorithmically incompressible binary patterns can be morphically compressed, with respect to the local connectivities, in a binary morphic program. From the local connectivites, there emerges a global morphic connection that can be characterized by a low length binary string, leading to the identification of chaotic categorial dynamics, underlying the algorithmically random pattern. The work focuses on infinite binary chains of C2, which is a category that implements an X-OR-based categorial logical calculus.

  2. Low autocorrelation binary sequences

    Science.gov (United States)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  3. Microlensing modulation by binaries

    CERN Document Server

    Dubath, F; Durrer, R; Dubath, Florian; Gasparini, Maria Alice; Durrer, Ruth

    2006-01-01

    We compute the effect of the lens quadrupole on microlensing. The time dependence of the quadrupole can lead to specific modulations of the amplification signal. We study especially binary system lenses in our galaxy. The modulation is observable if the rotation period of the system is smaller than the time over which the amplification is significant and if the impact parameter of the passing light ray is sufficiently close to the Einstein radius so that the amplification is very large. Observations of this modulation can reveal important information on the quadrupole and thus on the gravitational radiation emitted by the lens.

  4. Monolayer compression induces fluidization in binary system of partially fluorinated alcohol (F4H11OH) with DPPC.

    Science.gov (United States)

    Nakahara, Hiromichi; Ohmine, Aya; Kai, Shoko; Shibata, Osamu

    2013-01-01

    A two-component Langmuir monolayer consisting of (perfluorobutyl)undecanol (F4H11OH) and dipalmitoylphosphatidylcholine (DPPC), a major component of pulmonary surfactants in mammals, has been investigated at the air-water interface. The binary monolayer has been systematically examined from both thermodynamic and morphological perspectives. The excess Gibbs free energy of mixing has been calculated from surface pressure (π)-molecular area (A) isotherms, and the results indicate that the miscibility of the two-component system shows a maximum in thermodynamical stability when the mole fraction (X(F4H11OH)) is 0.3. Results from a two-dimensional phase diagram (π vs. X(F4H11OH)) are consistent with these findings and depict the degree of miscibility resulting from the variation in the transition and collapse pressures relative to the concentration of X(F4H11OH). The miscibility is also supported by in situ Brewster angle microscopy and fluorescence microscopy, as well as ex situ atomic force microscopy for the system after transfer onto a mica substrate. Aside from temperature, a known driving force for the fluidization of DPPC monolayers is a change in surface composition caused by the addition of additive molecules. In the present study, however, the fluidization is driven by increasing surface pressures even at constant X(F4H11OH). Such a fluidization is a fascinating property when looked at in context of its potential implications for pulmonary replacement therapy, and hence, this study provides a fundamental insight into designing fluorinated materials for biomedical use.

  5. Experimental Measurements of Longitudinal and Transverse Dispersion in Miscible Fluids with a High Viscosity and Density Contrast

    Science.gov (United States)

    Alkindi, A.; Bijeljic, B.; Muggeridge, A.

    2008-12-01

    Diffusion and advective dispersion may have a significant influence on the mixing between miscible fluids during displacement processes in porous media. This is particularly important when intimate mixing may result in important changes to the fluid behaviour. For example in oil recovery, mixing between injected and connate water will tend to reduce the efficiency of low salinity water injection. On the other hand recovery may be increased if injected gas mixes with high viscosity oil increasing its mobility. Most experimental data for longitudinal and transverse dispersion have been obtained using fluid pairs with very similar viscosities and densities. The traditional description (Perkins and Johnston, 1963) suggests that longitudinal dispersion decreases as mobility ratio increases. It also suggests that gravity will tend to reduce transverse dispersion. We provide experimental measurements of longitudinal (KL) and transverse (KT) dispersion at low Reynolds number as a function of Peclet number for the first contact miscible ethanol- glycerol fluid system flowing in a porous media formed from glass beads. These fluids have a high viscosity ratio of over 1000 and a significant density difference of 470 kg m-3. We show that both KL and KT are similar to values measured for a water-brine system but that KT is reduced when the less dense ethanol is flowing above the denser glycerol.

  6. Miscibility and interaction between 1-alkanol and short-chain phosphocholine in the adsorbed film and micelles.

    Science.gov (United States)

    Takajo, Yuichi; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto; Yamanaka, Michio

    2007-09-01

    The miscibility and interaction of 1-hexanol (C6OH) and 1-heptanol (C7OH) with 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in the adsorbed films and micelles were investigated by measuring the surface tension of aqueous C6OH-DHPC and aqueous C7OH-DHPC solutions. The surface density, the mean molecular area, the composition of the adsorbed film, and the excess Gibbs energy of adsorption g(H,E), were estimated. Further, the critical micelle concentration of the mixtures was determined from the surface tension versus molality curves; the micellar composition was calculated. The miscibility of the 1-alkanols and DHPC molecules in the adsorbed film and micelles was examined using the phase diagram of adsorption (PDA) and that of micellization (PDM). The PDA and the composition dependence of g(H,E) indicated the non-ideal mixing of the 1-alkanols and DHPC molecules due to the attractive interaction between the molecules in the adsorbed film, while the PDM indicated that the 1-alkanol molecules were not incorporated in the micelles within DHPC rich region. The dependence of the mean molecular area of the mixtures on the surface composition suggested that the packing property of the adsorbed film depends on the chain length of 1-alkanol: C6OH expands the DHPC adsorbed film more than C7OH.

  7. Simulation Study on Miscibility Effect of CO2/Solvent Injection for Enhanced Oil Recovery at Nonisothermal Conditions

    Directory of Open Access Journals (Sweden)

    Moon Sik Jeong

    2016-01-01

    Full Text Available The minimum miscibility pressure (MMP determines the main mechanism of CO2 flooding, which is either an immiscible or miscible process. This paper examines the recovery improvements of CO2 flooding in terms of both the injection temperature and solvent composition. The results show that a lower temperature injection and LPG (liquefied petroleum gas mixture can considerably improve oil recovery due to the reduced MMP in the swept area caused by the injected solvent. For the pure CO2 injection at the reservoir temperature, oil recovery is 59% after 1.0 PV CO2 injection. The oil recoveries by CO2-LPG mixtures are improved to 73% with 0.1 mole fractions of LPG and 81% with 0.2 mole fractions of LPG. The recovery factor from low-temperature CO2 injection is 78%, which is 32% higher compared to the isothermal case. The recoveries obtained by low-temperature CO2-LPG injection increase up to 87% of the initial oil. Heat transfer between the reservoir and the formation of over/underburden should be considered in order to describe the process more accurately. Additionally, the recovery factors from the heat transfer models are decreased by 4–12% in comparison with the original nonisothermal models.

  8. Development and evaluation of lafutidine solid dispersion via hot melt extrusion: Investigating drug-polymer miscibility with advanced characterisation

    Directory of Open Access Journals (Sweden)

    Ritesh Fule

    2014-04-01

    Full Text Available In current study, immediate release solid dispersion (SD formulation of antiulcer drug lafutidine (LAFT was developed using hot melt extrusion (HME technique. Amphiphilic Soluplus® used as a primary solubilizing agent, with different concentrations of selected surfactants like PEG 400, Lutrol F127 (LF127, Lutrol F68 (LF68 were used to investigate their influence on formulations processing via HME. Prepared amorphous glassy solid dispersion was found to be thermodynamically and physicochemically stable. On the contrary, traces of crystalline LAFT not observed in the extrudates according to differential scanning calorimetry (DSC, X-ray diffraction (XRD, scanning electron microscopy (SEM and Raman spectroscopy. Raman micro spectrometry had the lowest detection limit of LAFT crystals compared with XRD and DSC. Atomic Force microscopy (AFM studies revealed drug- polymer molecular miscibility and surface interaction at micro level. 1H–COSY NMR spectroscopy confirmed miscibility and interaction between LAFT and Soluplus®, with chemical shift drifting and line broadening. MD simulation studies using computational modelling showed intermolecular interaction between molecules. Dissolution rate and solubility of LAFT was enhanced remarkably in developed SD systems. Optimized ratio of polymer and surfactants played crucial role in dissolution rate enhancement of LAFT SD. The obtained results suggested that developed LAFT has promising potential for oral delivery and might be an efficacious approach for enhancing the therapeutic potential of LAFT.

  9. Filling the Income Gap

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Income distribution has become one of the people’s main concerns in China where more than 30 years of reform and opening up have also resulted in an ever-expanding wealth gap. But narrowing down the

  10. Studies of mixing properties of binary systems of 2-propanol with hexadecane and squalane at T = (298.15, 303.15, and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Gyan P. [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India)], E-mail: gyan.dubey@rediffmail.com; Sharma, Monika [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India)], E-mail: sharmamonika20@rediffmail.com

    2009-01-15

    The present paper reports the experimental data for density, {rho}, viscosity, {eta}, and speeds of sound, u for the binary mixtures of 2-propanol, (CH{sub 3}){sub 2}CHOH with hexadecane, C{sub 16}H{sub 34} over the miscibility region (0 < x{sub 1} < 1) and with squalane (2,4,6,10,15,19,23-hexametyltetracosane), C{sub 30}H{sub 62} over the miscibility region (0 < x{sub 1} < 0.6) at T = (298.15, 303.15, and 308.15) K. The experimental data have been used to calculate various parameters like excess molar volumes, V{sub m}{sup E}, viscosity deviations, {delta}{eta}, excess molar isentropic compressibility, K{sub S,m}{sup E}, and deviations in speed of sound, u{sup D}, from their ideal values u{sup id}. These excess parameters and deviations are used to interpret the molecular interactions in these binary mixtures.

  11. Evolution of Binaries in Dense Stellar Systems

    CERN Document Server

    Ivanova, Natalia

    2011-01-01

    In contrast to the field, the binaries in dense stellar systems are frequently not primordial, and could be either dynamically formed or significantly altered from their primordial states. Destruction and formation of binaries occur in parallel all the time. The destruction, which constantly removes soft binaries from a binary pool, works as an energy sink and could be a reason for cluster entering the binary-burning phase. The true binary fraction is greater than observed, as a result, the observable binary fraction evolves differently from the predictions. Combined measurements of binary fractions in globular clusters suggest that most of the clusters are still core-contracting. The formation, on other hand, affects most the more evolutionary advanced stars, which significantly enhances the population of X-ray sources in globular clusters. The formation of binaries with a compact objects proceeds mainly through physical collisions, binary-binary and single-binary encounters; however, it is the dynamical for...

  12. Spin Correlation in Binary Systems

    CERN Document Server

    Farbiash, N; Farbiash, Netzach; Steinitz, Raphael

    2004-01-01

    We examine the correlation of projected rotational velocities in binary systems. It is an extension of previous work (Steinitz and Pyper, 1970; Levato, 1974). An enlarged data basis and new tests enable us to conclude that there is indeed correlation between the projected rotational velocities of components of binaries. In fact we suggest that spins are already correlated.

  13. Evolutionary Memory in Binary Systems?

    CERN Document Server

    Steinitz, N F R

    2004-01-01

    Correlation between the spins (rotational velocities) in binaries has previously been established. We now continue and show that the degree of spin correlation is independent of the components' separation. Such a result might be related for example to Zhang's non-linear model for the formation of binary stars from a nebula.

  14. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Matthew J. Benacquista

    2013-03-01

    Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  15. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    XuChengqian; ZhaoXiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP)is proposed .A new class of block design-Difference Family Pair (DFP)is also proposed .The relationship between PCSP and DFP,the properties and exising conditions of PCSP and the recursive constructions for PCSP are given.

  16. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    Xu Chengqian; Zhao Xiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP) is proposed. A new class of block design-Difference Family Pair (DFP) is also proposed.The relationship between PCSP and DFP, the properties and existing conditions of PCSP and the recursive constructions for PCSP are given.

  17. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew J.

    2006-02-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  18. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew

    2002-01-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing $10^4 - 10^6$ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct $N$-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  19. Signature Visualization of Software Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Panas, T

    2008-07-01

    In this paper we present work on the visualization of software binaries. In particular, we utilize ROSE, an open source compiler infrastructure, to pre-process software binaries, and we apply a landscape metaphor to visualize the signature of each binary (malware). We define the signature of a binary as a metric-based layout of the functions contained in the binary. In our initial experiment, we visualize the signatures of a series of computer worms that all originate from the same line. These visualizations are useful for a number of reasons. First, the images reveal how the archetype has evolved over a series of versions of one worm. Second, one can see the distinct changes between version. This allows the viewer to form conclusions about the development cycle of a particular worm.

  20. Observing binary inspiral with LIGO

    CERN Document Server

    Finn, L S

    1994-01-01

    Gravitational radiation from a binary neutron star or black hole system leads to orbital decay and the eventual coalescence of the binary's components. During the last several minutes before the binary components coalesce, the radiation will enter the bandwidth of the United States Laser Inteferometer Gravitational-wave Observatory (LIGO) and the French/Italian VIRGO gravitational radiation detector. The combination of detector sensitivity, signal strength, and source density and distribution all point to binary inspiral as the most likely candidate for observation among all the anticipated sources of gravitational radiation for LIGO/VIRGO. Here I review briefly some of the questions that are posed to theorists by the impending observation of binary inspiral.

  1. Towards Physarum Binary Adders

    CERN Document Server

    Jones, Jeff; 10.1016/j.biosystems.2010.04.005

    2010-01-01

    Plasmodium of \\emph{Physarum polycephalum} is a single cell visible by unaided eye. The plasmodium's foraging behaviour is interpreted in terms of computation. Input data is a configuration of nutrients, result of computation is a network of plasmodium's cytoplasmic tubes spanning sources of nutrients. Tsuda et al (2004) experimentally demonstrated that basic logical gates can be implemented in foraging behaviour of the plasmodium. We simplify the original designs of the gates and show --- in computer models --- that the plasmodium is capable for computation of two-input two-output gate $ \\to $ and three-input two-output $ \\to $. We assemble the gates in a binary one-bit adder and demonstrate validity of the design using computer simulation.

  2. Towards Physarum binary adders.

    Science.gov (United States)

    Jones, Jeff; Adamatzky, Andrew

    2010-07-01

    Plasmodium of Physarum polycephalum is a single cell visible by unaided eye. The plasmodium's foraging behaviour is interpreted in terms of computation. Input data is a configuration of nutrients, result of computation is a network of plasmodium's cytoplasmic tubes spanning sources of nutrients. Tsuda et al. (2004) experimentally demonstrated that basic logical gates can be implemented in foraging behaviour of the plasmodium. We simplify the original designs of the gates and show - in computer models - that the plasmodium is capable for computation of two-input two-output gate x, y-->xy, x+y and three-input two-output x,y,z-->x yz,x+y+z. We assemble the gates in a binary one-bit adder and demonstrate validity of the design using computer simulation.

  3. Eccentric Binary Millisecond Pulsars

    CERN Document Server

    Freire, Paulo C C

    2009-01-01

    In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have a much wider range of masses (1.3 to > 2 solar masses) than the normal and mildly recycled pulsars found in double neutron star (DNS) systems (1.25 < Mp < 1.44 solar masses). This is very likely to be due to the prolonged accretion episode that is thought to be required to form a MSP. The likely existence of massive MSPs makes them a powerful probe for understanding the behavior of matter at densities larger than that of the atomic nucleus; in particular, the precise measurement of the mass of PSR J1903+0327 ($1.67 +/- 0.01 solar masses) excludes several "soft" equations of state for dense matter.

  4. Indirectly suspended droplet microextraction of water-miscible organic solvents by salting-out effect for the determination of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Daneshfar, Ali; Khezeli, Tahere

    2014-12-01

    A simple and low-cost method that indirectly suspended droplet microextraction of water-miscible organic solvents (ISDME) by salting-out effect before high-performance liquid chromatography and ultraviolet (HPLC-UV) detection was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in different samples. The ISDME is a combination of salting-out extraction of water-miscible organic solvent and directly suspended droplet microextraction (DSDME). Ninety-five microliters water-miscible organic solvent (1-propanol) was added to a 500-µL sample. A homogeneous solution was formed immediately. To produce a steady vortex at the top of the solution, the sample was agitated at 700 rpm using a magnetic stirrer. By the addition of ammonium sulfate (saturated solution) to the homogeneous solution, 1-propanol was separated and collected at the bottom of the steady vortex. Finally, 20 µL 1-propanol was injected into HPLC-UV. The effects of important parameters such as water-miscible organic solvent (type and volume), type of salt, and extraction time were evaluated. Under optimum conditions, the method has a good linear calibration range (0.1 µg/L-300 µg/L), coefficients of determination (R(2) > 0.998), low limits of detection (between 0.02 µg/L and 0.27 µg/L), and acceptable recovery (>85.0%).

  5. Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir (Pre-Work and Project Proposal), Class I

    Energy Technology Data Exchange (ETDEWEB)

    Bou-Mikael, Sami

    2002-02-05

    This project outlines a proposal to improve the recovery of light oil from waterflooded fluvial dominated deltaic (FDD) reservoir through a miscible carbon dioxide (CO2) flood. The site is the Port Neches Field in Orange County, Texas. The field is well explored and well exploited. The project area is 270 acres within the Port Neches Field.

  6. Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir (Pre-Work and Project Proposal - Appendix)

    Energy Technology Data Exchange (ETDEWEB)

    Bou-Mikael, Sami

    2002-02-05

    The main objective of the Port Neches Project was to determine the feasibility and producibility of CO2 miscible flooding techniques enhanced with horizontal drilling applied to a Fluvial Dominated Deltaic reservoir. The second was to disseminate the knowledge gained through established Technology Transfer mechanisms to support DOE's programmatic objectives of increasing domestic oil production and reducing abandonment of oil fields.

  7. Numerical analysis of phase decomposition in A-B binary alloys using Cahn-Hilliard equations

    Directory of Open Access Journals (Sweden)

    Susana Lezama-Alvarez

    2013-01-01

    Full Text Available The analysis of phase decomposition was carried out using the nonlinear and linear Cahn-Hilliard equations in a hypothetical A-B alloy system with a miscibility gap. These equations were solved by the explicit finite difference method assuming a regular solution model. The supersaturated solid solution and decomposed phases were considered to have an fcc structure. Different aging temperatures and thermodynamic interaction parameters ΩA-B were used to simulate different alloy systems. The numerical simulation results showed that the growth kinetics of phase decomposition in the alloy with 30at.% A was slower than that of 50 at.% A. Additionally, the start time and modulation wavelength of phase decomposition are strongly affected by the thermodynamic interaction parameter ΩA-B value. The numerical simulation results showed that the growth kinetics of phase decomposition with the linear equation is slower than that with the nonlinear one.

  8. Missing the gap

    DEFF Research Database (Denmark)

    Tanggaard, Lene; Glaveanu, Vlad Petre

    creative learning at the borders need not minimize differences, but handle and learn from them? If not, schools and educational institutions risk becoming bad copies of the labour marked instead of enabling students to enter the market with something new, something radically dissimilar from what......Missing the gap This paper is focused on an exploration of creative learning involved in boundary crossing (Tanggaard, 2007). Our aim is to explore the trajectories and pathways realised by students as they move from education to work and vice versa (Tanggaard & Beghetto, 2015), guided...... by the premise that difference and gaps are places where creative learning is intensified (Glaveanu & Gillespie, 2015). The public discourse around education is often concerned with minding or avoiding the gap by making education more relevant for or similar to the labour market, but what if facilitating...

  9. Gap Cycling for SWIFT

    CERN Document Server

    Corum, Curtis A; Snyder, Carl J; Garwood, Michael

    2013-01-01

    Purpose: SWIFT (SWeep Imaging with Fourier Transformation) is a non- Cartesian MRI method with unique features and capabilities. In SWIFT, radiofrequency (RF) excitation and reception are performed nearly simultaneously, by rapidly switching between transmit and receive during a frequency-swept RF pulse. Because both the transmitted pulse and data acquisition are simultaneously amplitude-modulated in SWIFT (in contrast to continuous RF excitation and uninterrupted data acquisition in more familiar MRI sequences), crosstalk between different frequency bands occurs in the data. This crosstalk leads to a "bulls-eye" artifact in SWIFT images. We present a method to cancel this inter-band crosstalk by cycling the pulse and receive gap positions relative to the un-gapped pulse shape. We call this strategy "gap cycling." Methods: We carry out theoretical analysis, simulation and experiments to characterize the signal chain, resulting artifacts, and their elimination for SWIFT. Results: Theoretical analysis reveals t...

  10. Semantic Gaps Are Dangerous

    DEFF Research Database (Denmark)

    Ejstrup, Michael; le Fevre Jakobsen, Bjarne

    Semantic gaps are dangerous Language adapts to the environment where it serves as a tool to communication. Language is a social agreement, and we all have to stick to both grammaticalized and non-grammaticalized rules in order to pass information about the world around us. As such language develops...... unpolite language and tend to create dangerous relations where specialy language creates problems and trouble that could be avoided if we had better language tools at hand. But we have not these tools of communication, and we are in a situation today where media and specially digital and social media......, supported by new possibilities of migration, create dangerous situations. How can we avoid these accidental gaps in language and specially the gaps in semantic and metaphoric tools. Do we have to keep silent and stop discusing certain isues, or do we have other ways to get acces to sufficient language tools...

  11. Mathematical and numerical analysis of a multi-velocity multi-fluid model for interpenetration of miscible fluids; Analyse mathematique et numerique d'un modele multifluide multivitesse pour l'interpenetration de fluides miscibles

    Energy Technology Data Exchange (ETDEWEB)

    Enaux, C

    2007-11-15

    The simulation of indirect laser implosion requires an accurate knowledge of the inter-penetration of the laser target materials turned into plasma. This work is devoted to the study of a multi-velocity multi-fluid model recently proposed by Scannapieco and Cheng (SC) to describe the inter-penetration of miscible fluids. In this document, we begin with presenting the SC model in the context of miscible fluids flow modelling. Afterwards, the mathematical analysis of the model is carried out (study of the hyperbolicity, existence of a strictly convex mathematical entropy, asymptotic analysis and diffusion limit). As a conclusion the problem is well set. Then, we focus on the problem of numerical resolution of systems of conservation laws with a relaxation source term, because SC model belongs to this class. The main difficulty of this task is to capture on a coarse grid the asymptotic behaviour of the system when the source term is stiff. The main contribution of this work lies in the proposition of a new technique, allowing us to construct a Lagrangian numerical flux taking into account the presence of the source term. This technique is applied first on the model-problem of a one-dimensional Euler system with friction, and then on the multi-fluid SC model. In both cases, we prove that the new scheme is asymptotic-preserving and entropic under a CFL-like condition. The two-dimensional extension of the scheme is done by using a standard alternate directions method. Some numerical results highlight the contribution of the new flux, compared with a standard Lagrange plus Remap scheme where the source term is processed using an operator splitting. (author)

  12. The longevity gender gap

    DEFF Research Database (Denmark)

    Aviv, Abraham; Shay, Jerry; Christensen, Kaare

    2005-01-01

    In this Perspective, we focus on the greater longevity of women as compared with men. We propose that, like aging itself, the longevity gender gap is exceedingly complex and argue that it may arise from sex-related hormonal differences and from somatic cell selection that favors cells more...... resistant to the ravages of time. We discuss the interplay of these factors with telomere biology and oxidative stress and suggest that an explanation for the longevity gender gap may arise from a better understanding of the differences in telomere dynamics between men and women....

  13. Dynamical Evolution of Wide Binaries

    Directory of Open Access Journals (Sweden)

    Esmeralda H. Mallada

    2001-01-01

    Full Text Available We simulate numerically encounters of wide binaries with field stars and Giant Molecular Clouds (GMCs by means of the impulse approximation. We analyze the time evolution of the distributions of eccentricities and semimajor axes of wide binaries with given initial conditions, at intervals of 109 yr, up to 1010 yr (assumed age of the Galaxy. We compute the fraction of surviving binaries for stellar encounters, for GMC encounters and for a combination of both, and hence, the dynamical lifetime for different semimajor axes and different masses of binaries (0.5, 1, 1.2, 1.5, 2.5, and 3 Msolar. We find that the dynamical lifetime of wide binaries considering only GMCs is half than that considering only stars. For encounters with GMCs we analyze the influence of the initial inclination of the orbital plane of the binary with respect to the plane perpendicular to the relative velocity vector of the binary and the GMC. We find that the perturbation is maximum when the angle is minimum.

  14. Chaotic zones around gravitating binaries

    CERN Document Server

    Shevchenko, Ivan I

    2014-01-01

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound bodies (a double star, a double black hole, a binary asteroid, etc.) is estimated analytically, in function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the binary periods. The binary's mass ratio, above which such a chaotic zone is universally present, is also estimated.

  15. Modified evolution of stellar binaries from supermassive black hole binaries

    Science.gov (United States)

    Liu, Bin; Wang, Yi-Han; Yuan, Ye-Fei

    2017-04-01

    The evolution of main-sequence binaries resided in the galactic centre is influenced a lot by the central supermassive black hole (SMBH). Due to this perturbation, the stars in a dense environment are likely to experience mergers or collisions through secular or non-secular interactions. In this work, we study the dynamics of the stellar binaries at galactic centre, perturbed by another distant SMBH. Geometrically, such a four-body system is supposed to be decomposed into the inner triple (SMBH-star-star) and the outer triple (SMBH-stellar binary-SMBH). We survey the parameter space and determine the criteria analytically for the stellar mergers and the tidal disruption events (TDEs). For a relative distant and equal masses SMBH binary, the stars have more opportunities to merge as a result from the Lidov-Kozai (LK) oscillations in the inner triple. With a sample of tight stellar binaries, our numerical experiments reveal that a significant fraction of the binaries, ∼70 per cent, experience merger eventually. Whereas the majority of the stellar TDEs are likely to occur at a close periapses to the SMBH, induced by the outer Kozai effect. The tidal disruptions are found numerically as many as ∼10 per cent for a close SMBH binary that is enhanced significantly than the one without the external SMBH. These effects require the outer perturber to have an inclined orbit (≥40°) relatively to the inner orbital plane and may lead to a burst of the extremely astronomical events associated with the detection of the SMBH binary.

  16. Melting and crystallization behavior of partially miscible high density polyethylene/ethylene vinyl acetate copolymer (HDPE/EVA) blends

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang; Zou, Huawei, E-mail: hwzou@163.com; Liang, Mei, E-mail: liangmeiww@163.com; Cao, Ya

    2014-06-01

    Highlights: • HDPE/EVA blends undergo phase separation, making it an interesting topic to investigate the relationships between miscibility and crystallization. • Influences from blending on the crystallization kinetics were successfully evaluated by Friedman's and Khanna's method. • X-ray diffraction studies revealed that blending with EVA the unit length of the unit cell of the HDPE increases. • Thermal fractionation method was successfully used to characterize the co-crystallization in HDPE/EVA blends. - Abstract: Crystallization studies on HDPE/EVA blends and the individual components were performed with differential scanning calorimetry (DSC) technique and wide angle X-ray scattering (WAXS). Influences of blending on the crystallization kinetics of each component in HDPE/EVA mixture were evaluated by Friedman's activation energy and Khanna's crystallization rate coefficient (CRC). The addition of more HDPE into the EVA matrix causes more heterogeneous nucleation while the addition of EVA would hinder the nucleation of HDPE at the beginning of cooling process. Inter-molecular interaction in the melt facilitated the crystallization of both EVA and HDPE components. X-ray diffraction studies revealed that HDPE and EVA have orthorhombic unit cell. Blending with EVA did not affect the crystalline structure of HDPE. In addition, a little shift of (1 1 0), (2 0 0) and (0 2 0) crystalline peaks toward lower 2θ values of samples indicating a little increase of unit cell parameters of the orthorhombic unit cell of polyethylene. Thermal fractionation results showed that co-crystallization took place in the HDPE/EVA blend. All those results indicated that the polymer pair we choose was partially miscible.

  17. 'Mind the Gap!'

    DEFF Research Database (Denmark)

    Persson, Karl Gunnar

    This paper challenges the widely held view that sharply falling real transport costs closed the transatlantic gap in grain prices in the second half of the 19th century. Several new results emerge from an analysis of a new data set of weekly wheat prices and freight costs from New York to UK mark...

  18. Bridging the Technological Gap.

    Science.gov (United States)

    Lazow, Robert; And Others

    The aim of "Bridging the Technological Gap" (BTG), a federally funded demonstration project, is to use microcomputer technology in the rehabilitation of the psychiatrically disabled. Through the use of a custom designed microcomputer software package, clients receive remediation in areas of specific cognitive and behavioral deficits. The project…

  19. Closing the Gap

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China's recent economic success has brought positive changes to its urban population,but left those in the countryside way behind.The gap in income and living standrs that always existed between urban and rural dwellers has widened alarmingly in the past two decades,causing serious problems.

  20. Estimating Gender Wage Gaps

    Science.gov (United States)

    McDonald, Judith A.; Thornton, Robert J.

    2011-01-01

    Course research projects that use easy-to-access real-world data and that generate findings with which undergraduate students can readily identify are hard to find. The authors describe a project that requires students to estimate the current female-male earnings gap for new college graduates. The project also enables students to see to what…

  1. Structuring the Information Gap.

    Science.gov (United States)

    Edge, Julian

    1984-01-01

    Describes an information gap procedure to teach a new structure which requires students to look for and exchange information in order to complete a task in an English as a second language class. Illustrates the method with a set of materials and suggests ways for teachers to produce similar materials. (SED)

  2. Band gap bowing in NixMg1-xO

    Science.gov (United States)

    Niedermeier, Christian A.; Råsander, Mikael; Rhode, Sneha; Kachkanov, Vyacheslav; Zou, Bin; Alford, Neil; Moram, Michelle A.

    2016-08-01

    Epitaxial transparent oxide NixMg1-xO (0 ≤ x ≤ 1) thin films were grown on MgO(100) substrates by pulsed laser deposition. High-resolution synchrotron X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the thin films are compositionally and structurally homogeneous, forming a completely miscible solid solution. Nevertheless, the composition dependence of the NixMg1-xO optical band gap shows a strong non-parabolic bowing with a discontinuity at dilute NiO concentrations of x band structure and the density of states demonstrate that deep Ni 3d levels are introduced into the MgO band gap, which significantly reduce the fundamental gap as confirmed by optical absorption spectra. These states broaden into a Ni 3d-derived conduction band for x > 0.074 and account for the anomalously large band gap narrowing in the NixMg1-xO solid solution system.

  3. Stability of binaries. Part II: Rubble-pile binaries

    Science.gov (United States)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  4. Simulation and Experimental on the Solvation Interaction between the GAP Matrix and Insensitive Energetic Plasticizers in Solid Propellants.

    Science.gov (United States)

    Zhao, Yu; Zhang, Xiaohong; Zhang, Wei; Xu, Hongjun; Xie, Wuxi; Du, Jiaojiao; Liu, Yingzhe

    2016-02-11

    Multimethods of simulation and experiment have been performed to investigate the interaction between glycidyl azide polymer (GAP) matrix and insensitive energetic plasticizers N-butyl-N-(2-nitroxy-ethyl)nitramine (Bu-NENA) and bis(2,2-dinitropropyl)formal/acetal (BDNPF/A). To start with, the blending energy distribution and Huggins parameters have been calculated, indicating fine miscibility between the GAP matrix and both plasticizers. The solubility parameter and binding energies show better compatibility between Bu-NENA and the GAP matrix than BDNPF/A, owing to stronger interactions. The interaction mechanism includes both hydrogen bonds and van der Waals forces. The low field NMR physical cross-link density and dynamic rheological behaviors imply larger disentanglement effect of Bu-NENA in the GAP matrix. The dynamic mechanical performance of elastomers show lower glass transition temperature of GAP/Bu-NENA blends, as supportive proof of stronger interactions between the GAP matrix and Bu-NENA in comparison with BDNPF/A.

  5. Binary nucleation beyond capillarity approximation

    NARCIS (Netherlands)

    Kalikmanov, V.I.

    2010-01-01

    Large discrepancies between binary classical nucleation theory (BCNT) and experiments result from adsorption effects and inability of BCNT, based on the phenomenological capillarity approximation, to treat small clusters. We propose a model aimed at eliminating both of these deficiencies. Adsorption

  6. Discs in misaligned binary systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2016-01-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...

  7. Simulating relativistic binaries with Whisky

    Science.gov (United States)

    Baiotti, L.

    We report about our first tests and results in simulating the last phase of the coalescence and the merger of binary relativistic stars. The simulations were performed using our code Whisky and mesh refinement through the Carpet driver.

  8. An adaptable binary entropy coder

    Science.gov (United States)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  9. Magnetic braking in ultracompact binaries

    CERN Document Server

    Farmer, Alison

    2010-01-01

    Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically coupled winds could in fact lead to substantial additional angular momentum losses. We remark that the scaling relations often invoked for the relative importance of gravitational and magnetic braking do not apply, and instead use simple non-empirical expressions for the braking rates. In order to remove significant angular momentum, the wind must be tied to field lines anchored in one of the binary's component stars; uncertainties remain as to the driving mechanism for such a wind. In the case of white dwarf accretors, we find that magnetic braking can potentially remove angular momentum on comparable or even shorter timescales than gravitational waves over a large range in orbital period. We present such a solution for the 17-minute binary AM CVn itself which a...

  10. Cryptography with DNA binary strands.

    Science.gov (United States)

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  11. AN IMPROVED DESIGN OF REVERSIBLE BINARY TO BINARY CODED DECIMAL CONVERTER FOR BINARY CODED DECIMAL MULTIPLICATION

    Directory of Open Access Journals (Sweden)

    Praveena Murugesan

    2014-01-01

    Full Text Available Reversible logic gates under ideal conditions produce zero power dissipation. This factor highlights the usage of these gates in optical computing, low power CMOS design, quantum optics and quantum computing. The growth of decimal arithmetic in various applications as stressed the need to propose the study on reversible binary to BCD converter which plays a greater role in decimal multiplication for providing faster results. The different parameters such as gate count,garbage output and constant input are more optimized in the proposed fixed bit binary to binary coded decimal converter than the existing design.

  12. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  13. Residue arithmetic in binary systems

    OpenAIRE

    Barsi, Ferruccio

    1988-01-01

    A natural approach to the problem of performing mod m computations in a binary system is presented and a solution is suggested which is based upon a straightforward relation between the residues of a same integer X with respect to different moduli. The proposed solution proves fruitful in various applications, such as converting binary integers to residue notation and mod m addition or multiplication. Even if the most usual implementation approach for mod m processors is based on look-up tabl...

  14. Coevolution of Binaries and Gaseous Discs

    CERN Document Server

    Fleming, David P

    2016-01-01

    The recent discoveries of circumbinary planets by $\\it Kepler$ raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc, and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc that drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for $10^4$ binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentri...

  15. Tidal Disruption Events by a Massive Black Hole Binary

    CERN Document Server

    Ricarte, Angelo; Dai, Lixin; Coppi, Paolo

    2015-01-01

    Massive black hole binaries (MBHBs) are a natural byproduct of galaxy mergers. Previous studies have shown that flares from stellar tidal disruption events (TDEs) are modified by the presence of a secondary perturber, causing interruptions in the light curve. We study the dynamics of TDE debris in the presence of a milliparsec-separated MBHB by integrating ballistic particle orbits in the time-varying potential of the binary. We find that gaps in the light curve appear when material misses the accretion radius on its first return to pericentre. Subsequent recurrences can be decomposed into "continuous" and "delayed" components, which exhibit different behaviour. We find that this potential can substantially alter the locations of stream self-intersections. When debris is confined to the plane, we find that close encounters with the secondary BH leave noticeable signatures on the fallback rate and can result in significant accretion onto the secondary BH. Tight, equal-mass MBHBs accrete equally, periodically t...

  16. Optical simulation of neutrino oscillations in binary waveguide arrays.

    Science.gov (United States)

    Marini, Andrea; Longhi, Stefano; Biancalana, Fabio

    2014-10-10

    We theoretically propose and investigate an optical analogue of neutrino oscillations in a pair of vertically displaced binary waveguide arrays with longitudinally modulated effective refractive index. Optical propagation is modeled through coupled-mode equations, which in the continuous limit converge to two coupled Dirac equations for fermionic particles with different mass states, analogously to neutrinos. In addition to simulating neutrino oscillation in the noninteracting regime, our optical setting enables us to explore neutrino interactions in extreme regimes that are expected to play an important role in massive supernova stars. In particular, we predict the quenching of neutrino oscillations and the existence of topological defects, i.e., neutrino solitons, which in our photonic simulator should be observable as excitation of optical gap solitons propagating along the binary arrays at high excitation intensities.

  17. Small Generation Gap

    Institute of Scientific and Technical Information of China (English)

    JANE SHAW

    1994-01-01

    IT was while I was making milk for my son that I discovered the generation gap between us. A little thing of two years and three months, my son stood on a big chair I brought him and joined me to make milk. Holding a small spoon in his plump little hand, he scooped flour out of a jar and poured it into the feeding bottle and then scooped milk powder and

  18. Minding the Gap

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, Millicent Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    Neutron & X-ray scattering provides nano- to meso-scale details of complex fluid structure; 1D electronic density maps dervied from SAXS yield molecular level insights; Neutron reflectivity provides substructure details of substrate supported complex fluids; Complex fluids composition can be optimized to support a wide variety of both soluble and membrane proteins; The water gap dimensions can be finely tuned through polymer component.

  19. Unsupervised learning of binary vectors

    Science.gov (United States)

    Copelli Lopes da Silva, Mauro

    In this thesis, unsupervised learning of binary vectors from data is studied using methods from Statistical Mechanics of disordered systems. In the model, data vectors are distributed according to a single symmetry-breaking direction. The aim of unsupervised learning is to provide a good approximation to this direction. The difference with respect to previous studies is the knowledge that this preferential direction has binary components. It is shown that sampling from the posterior distribution (Gibbs learning) leads, for general smooth distributions, to an exponentially fast approach to perfect learning in the asymptotic limit of large number of examples. If the distribution is non-smooth, then first order phase transitions to perfect learning are expected. In the limit of poor performance, a second order phase transition ("retarded learning") is predicted to occur if the data distribution is not biased. Using concepts from Bayesian inference, the center of mass of the Gibbs ensemble is shown to have maximal average (Bayes-optimal) performance. This upper bound for continuous vectors is extended to a discrete space, resulting in the clipped center of mass of the Gibbs ensemble having maximal average performance among the binary vectors. To calculate the performance of this best binary vector, the geometric properties of the center of mass of binary vectors are studied. The surprising result is found that the center of mass of infinite binary vectors which obey some simple constraints, is again a binary vector. When disorder is taken into account in the calculation, however, a vector with continuous components is obtained. The performance of the best binary vector is calculated and shown to always lie above that of Gibbs learning and below the Bayes-optimal performance. Making use of a variational approach under the replica symmetric ansatz, an optimal potential is constructed in the limits of zero temperature and mutual overlap 1. Minimization of this potential

  20. GapBlaster-A Graphical Gap Filler for Prokaryote Genomes.

    Science.gov (United States)

    de Sá, Pablo H C G; Miranda, Fábio; Veras, Adonney; de Melo, Diego Magalhães; Soares, Siomar; Pinheiro, Kenny; Guimarães, Luis; Azevedo, Vasco; Silva, Artur; Ramos, Rommel T J

    2016-01-01

    The advent of NGS (Next Generation Sequencing) technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer.

  1. GapBlaster-A Graphical Gap Filler for Prokaryote Genomes.

    Directory of Open Access Journals (Sweden)

    Pablo H C G de Sá

    Full Text Available The advent of NGS (Next Generation Sequencing technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer.

  2. Exoplanets Bouncing Between Binary Stars

    CERN Document Server

    Moeckel, Nickolas

    2012-01-01

    Exoplanetary systems are found not only among single stars, but also binaries of widely varying parameters. Binaries with separations of 100--1000 au are prevalent in the Solar neighborhood; at these separations planet formation around a binary member may largely proceed as if around a single star. During the early dynamical evolution of a planetary system, planet--planet scattering can eject planets from a star's grasp. In a binary, the motion of a planet ejected from one star has effectively entered a restricted three-body system consisting of itself and the two stars, and the equations of motion of the three body problem will apply as long as the ejected planet remains far from the remaining planets. Depending on its energy, escape from the binary as a whole may be impossible or delayed until the three-body approximation breaks down, and further close interactions with its planetary siblings boost its energy when it passes close to its parent star. Until then this planet may be able to transition from the ...

  3. Formation of Kuiper Belt Binaries

    CERN Document Server

    Goldreich, P; Sari, R; Goldreich, Peter; Lithwick, Yoram; Sari, Re'em

    2002-01-01

    It appears that at least several percent of large Kuiper belt objects are members of wide binaries. Physical collisions are too infrequent to account for their formation. Collisionless gravitational interactions are more promising. These provide two channels for binary formation. In each, the initial step is the formation of a transient binary when two large bodies penetrate each other's Hill spheres. Stabilization of a transient binary requires that it lose energy. Either dynamical friction due to small bodies or the scattering of a third large body can be responsible. Our estimates favor the former, albeit by a small margin. We predict that most objects of size comparable to those currently observed in the Kuiper belt are members of multiple systems. More specifically, we derive the probability that a large body is a member of a binary with semi-major axis of order a. The probability depends upon sigma, the total surface density, Sigma, the surface density of large bodies having radius R, and theta=10^-4, t...

  4. Play-level distributions of estimates of recovery factors for a miscible carbon dioxide enhanced oil recovery method used in oil reservoirs in the conterminous United States

    Science.gov (United States)

    Attanasi, E.D.; Freeman, P.A.

    2016-03-02

    In a U.S. Geological Survey (USGS) study, recovery-factor estimates were calculated by using a publicly available reservoir simulator (CO2 Prophet) to estimate how much oil might be recovered with the application of a miscible carbon dioxide (CO2) enhanced oil recovery (EOR) method to technically screened oil reservoirs located in onshore and State offshore areas in the conterminous United States. A recovery factor represents the percentage of an oil reservoir’s original oil in place estimated to be recoverable by the application of a miscible CO2-EOR method. The USGS estimates were calculated for 2,018 clastic and 1,681 carbonate candidate reservoirs in the “Significant Oil and Gas Fields of the United States Database” prepared by Nehring Associates, Inc. (2012).

  5. Gap Opening in 3D: Single Planet Gaps

    CERN Document Server

    Fung, Jeffrey

    2016-01-01

    Giant planets can clear deep gaps when embedded in 2D (razor-thin) viscous circumstellar disks. We show by direct simulation that giant planets are just as capable of carving out gaps in 3D. Surface density maps are similar between 2D and 3D, even in detail. In particular, the scaling $\\Sigma_{\\rm gap} \\propto q^{-2}$ of gap surface density with planet mass, derived from a global "zero-dimensional" balance of Lindblad and viscous torques, applies equally well to results obtained at higher dimensions. Our 3D simulations reveal extensive, near-sonic, meridional flows both inside and outside the gaps; these large-scale circulations might bear on disk compositional gradients, in dust or other chemical species. At high planet mass, gap edges are mildly Rayleigh unstable and intermittently shed streams of material into the gap - less so in 3D than in 2D.

  6. Determining CO2 storage potential during miscible CO2 enhanced oil recovery: Noble gas and stable isotope tracers

    Science.gov (United States)

    Shelton, Jenna L.; McIntosh, Jennifer C.; Hunt, Andrew; Beebe, Thomas L; Parker, Andrew D; Warwick, Peter; Drake, Ronald; McCray, John E.

    2016-01-01

    Rising atmospheric carbon dioxide (CO2) concentrations are fueling anthropogenic climate change. Geologic sequestration of anthropogenic CO2 in depleted oil reservoirs is one option for reducing CO2 emissions to the atmosphere while enhancing oil recovery. In order to evaluate the feasibility of using enhanced oil recovery (EOR) sites in the United States for permanent CO2 storage, an active multi-stage miscible CO2flooding project in the Permian Basin (North Ward Estes Field, near Wickett, Texas) was investigated. In addition, two major natural CO2 reservoirs in the southeastern Paradox Basin (McElmo Dome and Doe Canyon) were also investigated as they provide CO2 for EOR operations in the Permian Basin. Produced gas and water were collected from three different CO2 flooding phases (with different start dates) within the North Ward Estes Field to evaluate possible CO2 storage mechanisms and amounts of total CO2retention. McElmo Dome and Doe Canyon were sampled for produced gas to determine the noble gas and stable isotope signature of the original injected EOR gas and to confirm the source of this naturally-occurring CO2. As expected, the natural CO2produced from McElmo Dome and Doe Canyon is a mix of mantle and crustal sources. When comparing CO2 injection and production rates for the CO2 floods in the North Ward Estes Field, it appears that CO2 retention in the reservoir decreased over the course of the three injections, retaining 39%, 49% and 61% of the injected CO2 for the 2008, 2010, and 2013 projects, respectively, characteristic of maturing CO2 miscible flood projects. Noble gas isotopic composition of the injected and produced gas for the flood projects suggest no active fractionation, while δ13CCO2 values suggest no active CO2dissolution into formation water, or mineralization. CO2 volumes capable of dissolving in residual formation fluids were also estimated along with the potential to store pure-phase supercritical CO2. Using a combination

  7. Closing the stop gap

    Energy Technology Data Exchange (ETDEWEB)

    Czakon, Michal [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchnphysik und Kosmologie; Mitov, Alexander [Univ. of Cambridge (United Kingdom). Cavendish Lab.; Papucci, Michele [Lawrence Berkeley National Laboratory, CA (United States). Theoretical Physics Group; California Univ., Berkeley, CA (United States). Dept. of Physics; Ruderman, Joshua T. [Lawrence Berkeley National Laboratory, CA (United States). Theoretical Physics Group; California Univ., Berkeley, CA (United States). Dept. of Physics; New York Univ., NY (United States). Center for Cosmology and Particle Physics; Weiler, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); CERN - European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.

    2014-07-15

    Light stops are a hallmark of the most natural realizations of weak-scale supersymmetry. While stops have been extensively searched for, there remain open gaps around and below the top mass, due to similarities of stop and top signals with current statistics. We propose a new fast-track avenue to improve light stop searches for R-parity conserving supersymmetry, by comparing top cross section measurements to the theoretical prediction. Stop masses below ∝180 GeV can now be ruled out for a light neutralino. The possibility of a stop signal contaminating the top mass measurement is also briefly addressed.

  8. Mind the Gap

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    While a growing number of Chinese people are enjoying the benefits brought by economic reform and social development, some are being left behind. The divide between the rich and the poor is widening in China, resulting in an increasingly dissatisfied populace. Some argue that a wealth gap is not a big deal in a market economy and that the problem in China has been exaggerated. But in an article published by China Economic Times, Wu Zhongmin, a sociology professor at the Central Party School of the Commun...

  9. Photonic band gap materials

    Science.gov (United States)

    Cassagne, D.

    Photonic band gap materials Photonic band gap materials are periodic dielectric structures that control the propagation of electromagnetic waves. We describe the plane wave method, which allows to calculate the band structures of photonic crystals. By symmetry analysis and a perturbative approach, we predict the appearance of the low energy photonic band gaps of hexagonal structures. We propose new two-dimensional structures called graphite and boron nitride. Using a transfer matrix method, we calculate the transmission of the graphite structure and we show the crucial role of the coupling with external modes. We study the appearance of allowed modes in the photonic band gap by the introduction of localized defects in the periodicity. Finally, we discuss the properties of opals formed by self-organized silica microspheres, which are very promising for the fabrication of three-dimensional photonic crystals. Les matériaux à bandes interdites photoniques sont des structures diélectriques périodiques qui contrôlent la propagation des ondes électromagnétiques. Nous décrivons la méthode des ondes planes qui permet de calculer les structures de bandes des cristaux photoniques. Par une analyse de la symétrie et une approche perturbative, nous précisons les conditions d'existence des bandes interdites de basse énergie. Nous proposons de nouvelles structures bidimensionnelles appelées graphite et nitrure de bore. Grâce à une méthode de matrices de transfert, nous calculons la transmission de la structure graphite et nous mettons en évidence le rôle fondamental du couplage avec les modes extérieurs. Nous étudions l'apparition de modes permis dans la bande interdite grâce à l'introduction de défauts dans la périodicité. Enfin, nous discutons les propriétés des opales constituées de micro-billes de silice auto-organisées, qui sont très prometteuses pour la fabrication de cristaux photoniques tridimensionnels.

  10. Mind the gap

    Energy Technology Data Exchange (ETDEWEB)

    Bhagwat, M.S.; Roberts, C.D. [Argonne National Laboratory, Physics Division, Argonne, IL (United States); Krassnigg, A. [Universitaet Graz, Fachbereich Theoretische Physik, Graz (Austria); Maris, P. [University of Pittsburgh, Department of Physics and Astronomy, PA (United States)

    2007-03-15

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors. (orig.)

  11. Mind the gap.

    Energy Technology Data Exchange (ETDEWEB)

    Bhagwat, M. S.; Krassnigg, A.; Maris, P.; Roberts, C. D.; Physics; Univ. Graz; Univ. of Pittsburgh

    2007-03-01

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

  12. Unveiling the Gap

    DEFF Research Database (Denmark)

    Jensson, Pall; Rokkjær, Ole; Nørgaard, Bente

    discussing their NQF and Sweden has decided not to adjust to the EQF for the moment. Analysis of the subject focus for the individual programmes showed a high degree of variation. In the context of CDIO this means that what seems to be a well-known and commonly accepted definition of a discipline like IE...... needs, how universities decide what to teach, and how to bridge the gap. Do the university programs simply reflect the expertise of the faculty members? Is there need for increasing emphasis on continuing education? Is life-long education the answer, and has this been addressed by the CDIO community?...

  13. 高分子合金膜体系的相容性%Polymer blend miscibility and compatibility study for polymer alloy membrane material modification

    Institute of Scientific and Technical Information of China (English)

    孙本惠

    2011-01-01

    Polymer alloy technologies enable two or more polymers to be combined to realize new properties and levels of performance that were not possible with the individual polymers themselves. Therefore, they have become the most feasible and effective methods to realize the modification of polymeric membrane materials. The miscibility and compatibility of the various polymeric components, and thus the formation of homogenious phase to multiphase systems in casting solution play a decisive role in influencing the physical properties of the membranes prepared from it. In this article, the principles of thermodynamic to evaluate the miscibility and compatibility between polymers in polymer blend or alloy systems were thoroughly reviewed and discussed, including the basic theory and models for polymer miscibility study, the analysis of the ternary phase diagram of polymer A-polymer Insolvent mixture system, the thermodynamics of polymer blend phase separation during phase inversion, the critical phase separation condition, and the theoretical prediction of the polymer blend miscibility and compatibility.%高分子膜材料的合金化是最为简便有效的膜材料改性方法,不同聚合物之间的相容性是决定高分子合金膜物理性质的关键因素.文章讨论了涉及高分子合金膜体系相容性的几个主要热力学基础问题,包括两组分聚合物相容性的相图分析、高分子共混物在相转化过程中发生相分离的热力学、相分离的临界条件、高分子合金体系相容性的理论预测.

  14. An investigation into the influence of drug-polymer interactions on the miscibility, processability and structure of polyvinylpyrrolidone-based hot melt extrusion formulations.

    Science.gov (United States)

    Chan, Siok-Yee; Qi, Sheng; Craig, Duncan Q M

    2015-12-30

    While hot melt extrusion is now established within the pharmaceutical industry, the prediction of miscibility, processability and structural stability remains a pertinent issue, including the issue of whether molecular interaction is necessary for suitable performance. Here we integrate the use of theoretical and experimental drug-polymer interaction assessment with determination of processability and structure of dispersions in two polyvinylpyrrolidone-based polymers (PVP and PVP vinyl acetate, PVPVA). Caffeine and paracetamol were chosen as model drugs on the basis of their differing hydrogen bonding potential with PVP. Solubility parameter and interaction parameter calculations predicted a greater miscibility for paracetamol, while ATR-FTIR confirmed the hydrogen bonding propensity of the paracetamol with both polymers, with little interaction detected for caffeine. PVP was found to exhibit greater interaction and miscibility with paracetamol than did PVPVA. It was noted that lower processing temperatures (circa 40°C below the Tg of the polymer alone and Tm of the crystalline drug) and higher drug loadings with associated molecular dispersion up to 50% w/w were possible for the paracetamol dispersions, although molecular dispersion with the non-interactive caffeine was noted at loadings up to 20% w./w. A lower processing temperature was also noted for caffeine-loaded systems despite the absence of detectable interactions. The study has therefore indicated that theoretical and experimental detection of miscibility and drug-polymer interactions may lead to insights into product processing and extrudate structure, with direct molecular interaction representing a helpful but not essential aspect of drug-polymer combination prediction.

  15. Evaporative Instability in Binary Mixtures

    Science.gov (United States)

    Narayanan, Ranga; Uguz, Erdem

    2012-11-01

    In this talk we depict the physics of evaporative convection for binary systems in the presence of surface tension gradient effects. Two results are of importance. The first is that a binary system, in the absence of gravity, can generate an instability only when heated from the vapor side. This is to be contrasted with the case of a single component where instability can occur only when heated from the liquid side. The second result is that a binary system, in the presence of gravity, will generate an instability when heated from either the vapor or the liquid side provided the heating is strong enough. In addition to these results we show the conditions at which interfacial patterns can occur. Support from NSF OISE 0968313, Partner Univ. Fund and a Chateaubriand Fellowship is acknowledged.

  16. Marangoni Convection in Binary Mixtures

    CERN Document Server

    Zhang, J; Oron, A; Behringer, Robert P.; Oron, Alexander; Zhang, Jie

    2006-01-01

    Marangoni instabilities in binary mixtures are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of sodium chloride/water, we have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadowgraph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stage and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes i...

  17. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  18. Black Hole Binaries in Quiescence

    CERN Document Server

    Bailyn, Charles D

    2016-01-01

    I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in the optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-rary binaries, which has taken on a new importance in the era of gravitational wave astronomy.

  19. Board affiliation and pay gap

    Institute of Scientific and Technical Information of China (English)

    Shenglan; Chen; Hui; Ma; Danlu; Bu

    2014-01-01

    This paper examines the effects of board affiliation on the corporate pay gap.Using a sample of Chinese listed firms from 2005 to 2011, we find that boards with a greater presence of directors appointed by block shareholders have lower pay gaps. Furthermore, the governance effects of board affiliation with and without pay are distinguished. The empirical results show that board affiliation without pay is negatively related to the pay gap, while board affiliation with pay is positively related to the pay gap. Overall, the results shed light on how block shareholders affect their companies’ pay gaps through board affiliation.

  20. Implications of surfactant-induced flow for miscible-displacement estimation of air-water interfacial areas in unsaturated porous media.

    Science.gov (United States)

    Costanza-Robinson, Molly S; Zheng, Zheng; Henry, Eric J; Estabrook, Benjamin D; Littlefield, Malcolm H

    2012-10-16

    Surfactant miscible-displacement experiments represent a conventional means of estimating air-water interfacial area (A(I)) in unsaturated porous media. However, changes in surface tension during the experiment can potentially induce unsaturated flow, thereby altering interfacial areas and violating several fundamental method assumptions, including that of steady-state flow. In this work, the magnitude of surfactant-induced flow was quantified by monitoring moisture content and perturbations to effluent flow rate during miscible-displacement experiments conducted using a range of surfactant concentrations. For systems initially at 83% moisture saturation (S(W)), decreases of 18-43% S(W) occurred following surfactant introduction, with the magnitude and rate of drainage inversely related to the surface tension of the surfactant solution. Drainage induced by 0.1 mM sodium dodecyl benzene sulfonate, commonly used for A(I) estimation, resulted in effluent flow rate increases of up to 27% above steady-state conditions and is estimated to more than double the interfacial area over the course of the experiment. Depending on the surfactant concentration and the moisture content used to describe the system, A(I) estimates varied more than 3-fold. The magnitude of surfactant-induced flow is considerably larger than previously recognized and casts doubt on the reliability of A(I) estimation by surfactant miscible-displacement.

  1. Effect of pH on the physico-mechanical properties and miscibility of methyl cellulose/poly(acrylic acid) blends.

    Science.gov (United States)

    Negim, E S M; Nurpeissova, Zh A; Mangazbayeva, R A; Khatib, J M; Williams, C; Mun, G A

    2014-01-30

    The miscibility behavior and physico-mechanical properties between methyl cellulose (MC) of different molecular weights (4 × 10(4) and 8.3 × 10(4)g/mol) and poly(acrylic acid) (PAA) were studied by viscometry, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), tensile strength and scanning electron microscopy (SEM) using water as a solvent. Various formulations were designed to investigate the effects of process variables such as pH on the physico-mechanical and miscibility properties of MC/PAA blends. The rheological features for the obtained blends are strongly dependent on the molecular weight of the MC used and pH. The viscosity measurements showed that all blends have non-Newtonian shear thinning (pseudoplastic) behavior. These blends have a single glass transition indicating that these blends are able to form a miscible phase due to the formation of hydrogen bonds between the hydroxyl group of MC and the carboxyl group of PAA. The MC/PAA blends exhibit good mechanical properties, thermal stability, characteristics of a MC-PAA polymer network. SEM of the blends showed no phase separation, when compared with the pure MC and PAA.

  2. Gap Task Force

    CERN Document Server

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  3. Practical Binary Adaptive Block Coder

    CERN Document Server

    Reznik, Yuriy A

    2007-01-01

    This paper describes design of a low-complexity algorithm for adaptive encoding/ decoding of binary sequences produced by memoryless sources. The algorithm implements universal block codes constructed for a set of contexts identified by the numbers of non-zero bits in previous bits in a sequence. We derive a precise formula for asymptotic redundancy of such codes, which refines previous well-known estimate by Krichevsky and Trofimov, and provide experimental verification of this result. In our experimental study we also compare our implementation with existing binary adaptive encoders, such as JBIG's Q-coder, and MPEG AVC (ITU-T H.264)'s CABAC algorithms.

  4. Statistical Study of Visual Binaries

    CERN Document Server

    Abdel-Rahman, H I; Elsanhoury, W H

    2016-01-01

    In this paper, some statistical distributions of wide pairs included in Double Star Catalogue are investigated. Frequency distributions and testing hypothesis are derived for some basic parameters of visual binaries. The results reached indicate that, it was found that the magnitude difference is distributed exponentially, which means that the majority of the component of the selected systems is of the same spectral type. The distribution of the mass ratios is concentrated about 0.7 which agree with Salpeter mass function. The distribution of the linear separation appears to be exponentially, which contradict with previous studies for close binaries.

  5. Anti-Wear Performance and Mechanism of an Oil-Miscible Ionic Liquid as a Lubricant Additive

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [ORNL; Bansal, Dinesh G [ORNL; Yu, Bo [ORNL; Howe, Jane Y [ORNL; Luo, Huimin [ORNL; Dai, Sheng [ORNL; Li, Huaqing [ORNL; Blau, Peter Julian [ORNL; Bunting, Bruce G [ORNL; Mordukhovich, Gregory [GM R& D and Planning, Warren, Michigan; Smolenski, Donald [GM R& D and Planning, Warren, Michigan

    2012-01-01

    An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential anti-wear lubricant additive. Unlike most other ILs that have very low solubility in non-polar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347 oC, showed no corrosive attack to cast iron in ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron <8o). Most importantly, this phosphonium-based IL has demonstrated effective anti-scuffing and anti-wear characteristics when blended with lubricating oils. For example, a 5 wt.% addition into a synthetic base oil eliminated the scuffing failure experienced by the neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by three orders of magnitude. A synergistic effect on wear protection was observed with the current anti-wear additive when added into a fully-formulated engine oil. Nanostructure examination and composition analysis revealed a tribo-boundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the IL s anti-scuffing and anti-wear functionality.

  6. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2005-09-01

    The objective of this research project is to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data to observe changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 18 months of seismic monitoring, one baseline and six monitor surveys clearly imaged changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators.

  7. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2007-06-30

    The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.

  8. Thermodynamically consistent modeling and simulation of multi-component two-phase flow model with partial miscibility

    CERN Document Server

    Kou, Jisheng

    2016-01-01

    A general diffuse interface model with a realistic equation of state (e.g. Peng-Robinson equation of state) is proposed to describe the multi-component two-phase fluid flow based on the principles of the NVT-based framework which is a latest alternative over the NPT-based framework to model the realistic fluids. The proposed model uses the Helmholtz free energy rather than Gibbs free energy in the NPT-based framework. Different from the classical routines, we combine the first law of thermodynamics and related thermodynamical relations to derive the entropy balance equation, and then we derive a transport equation of the Helmholtz free energy density. Furthermore, by using the second law of thermodynamics, we derive a set of unified equations for both interfaces and bulk phases that can describe the partial miscibility of two fluids. A relation between the pressure gradient and chemical potential gradients is established, and this relation leads to a new formulation of the momentum balance equation, which dem...

  9. Effect of Water-miscible Organic Solvents on CYP450-mediated Metoprolol and Imipramine Metabolism in Rat Liver Microsomes.

    Science.gov (United States)

    Shah, T S; Kamble, S H; Patil, Pranali G; Iyer, K R

    2015-01-01

    The catalytic activity of cytochrome P450 enzymes is known to be affected by presence of organic solvents in in vitro assays. However, these effects tend to be variable and depend on the substrate and CYP450 isoform in question. In the present study, we have investigated effect of ten water miscible organic solvents (methanol, ethanol, propanol, isopropanol, acetone, acetonitrile, dimethylsulphoxide, dimethylformamide, dioxane and PEG400) on water soluble substrates of CYP450, metoprolol and imipramine, at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. Organic solvents studied had a concentration dependent inhibitory effect on the metoprolol and imipramine metabolism activity. Metoprolol metabolism was found to be more susceptible to the organic solvents, almost all the ten solvents had more or less inhibitory effect compared to imipramine metabolism. Except acetone, PEG400 and dimethylsulphoxide, all solvents had ~50% inhibition of total metoprolol metabolism activity, while in case of imipramine metabolism activity, only n-propanol, isopropanol and PEG400 had ~50% inhibition at 1% v/v. Interestingly, methanol, dimethylsulphoxide and acetonitrile had negligible effect on the imipramine metabolism (less than 10% inhibition at 1% v/v) while, total metoprolol metabolism activity was substantially inhibited by these solvents (MeOH 52%, DMSO 29% and ACN 47% at 1% v/v). In both cases, dioxane was found to be the most inhibitory solvent (~90% inhibition at 1% v/v).

  10. Effect of Water Miscible Organic Solvents on p-Nitrophenol Hydroxylase (CYP2E1) Activity in Rat Liver Microsomes.

    Science.gov (United States)

    Patil, Pranali G; Kamble, S H; Shah, T S; Iyer, K R

    2015-01-01

    Organic solvents used for solubilization of the substrates/NCEs are known to affect the activity of cytochrome P450 enzymes. Further, this effect varies with the solvents used, the substrates and CYP450 isoforms in question. In the present study, we have investigated the effect of ten commonly used water miscible organic solvents (methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, dimethyl sulphoxide, N,N-dimethyl formamide, dioxane and polyethylene glycol 400) on p-nitrophenol hydroxylase activity at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. All the solvents studied showed concentration dependent inhibition of the p-nitrophenol hydroxylase activity except acetonitrile which showed activation of the activity at concentration range studied. Out of ten solvents studied, dioxane was found to be the most inhibitory solvent (inhibition >90% at 0.25% v/v concentration). Overall, solvents like dimethyl sulphoxide, dimethyl formamide and dioxane appeared to be unsuitable for characterizing p-nitrophenol hydroxylase (CYP2E1-mediated) reactions due to a high degree of inhibition. On the other hand, methanol and acetonitrile at concentrations <0.5% v/v appeared to be appropriate solvents for substrate solubilization while evaluating CYP2E1-mediated catalysis. The results of this study imply that caution should be exercised while choosing solvents for dissolution of substrate during enzyme studies in liver microsomes.

  11. Hot Melt Extruded Amorphous Solid Dispersion of Posaconazole with Improved Bioavailability: Investigating Drug-Polymer Miscibility with Advanced Characterisation

    Directory of Open Access Journals (Sweden)

    Ritesh Fule

    2014-01-01

    Full Text Available Invasive antifungal infections are reasons for morbidity and mortality in immunogenic patients worldwide. Posaconazole is a most promising antifungal agent against all types of invasive infections with high % of cure rate. The marketed suspension formulation has low bioavailability and is needed to be taken with food. In this paper, PCZ hot melt extruded amorphous solid dispersion (SD with immediate release and improved bioavailability was prepared using Soluplus (Sol as primary carrier for solubilization. Surfactants such as PEG 400, Lutrol F27, Lutrol F68, and TPGS are also used in combination with Soluplus to improve the physicochemical performance of the formulation when it comes in contact with GI (gastrointestinal fluid. Drug-polymer miscibility of SD was investigated using advanced techniques. In the in vivo study, the AUC(0–72 and Cmax of PCZ/Soluplus were 11.5 and 11.74 time higher than those of pure PCZ. The formulation of the extrudate SD had an AUC(0–72 and Cmax higher than those with the commercial capsule (Noxafil. Molecular dynamic (MD simulation studies were carried out using in silico molecular modelling to understand the drug-polymer intermolecular behaviour. The results of this research ensure enhanced dissolution and bioavailability of the solid dispersion of PCZ prepared by HME compared with the PCZ suspension.

  12. Multiwalled carbon nanotubes incorporated into a miscible blend of poly(phenylenether/polystyrene – Processing and characterization

    Directory of Open Access Journals (Sweden)

    G. Olowojoba

    2013-07-01

    Full Text Available 4 wt% multiwalled carbon nanotubes (MWCNTs were incorporated into a miscible blend of polyphenylenether/polystyrene (PPE/PS on a twin-screw extruder at a screw speed of 600 rpm. The masterbatch obtained was diluted at 400 and 600 rpm to obtain lower MWCNT loadings in PPE/PS. Electron microscopy & optical microscopy images show very good MWCNT dispersion even at high filler loadings of 4 wt%, but slightly larger agglomerate size fractions are observable at higher screw speeds. While MWCNT addition enhanced the thermal stability of PPE/PS, a small change in glass transition was observed on the composites at different filler concentrations compared to PPE/PS. The specific heat capacity at glass transition decreases considerably until 2 wt% MWCNT and levels down thereafter for both processing conditions pointing to enhanced filler-matrix interaction at lower loadings. Storage modulus of the nanocomposites was enhanced significantly on MWCNT incorporation with reinforcing effect dropping considerably as a function of temperature, especially at lower filler contents. The modulus and the tensile strength of PPE/PS were only marginally enhanced in spite of excellent MWCNT dispersion in the matrix. Electrical percolation occurs at 0.4 wt% MWCNT content, and the electrical conductivity of 0.5 wt% MWCNT reinforced PPE/PS was close to 12 orders in magnitude higher compared to PPE/PS.

  13. Effect of water miscible organic solvents on p-nitrophenol hydroxylase (CYP2E1 activity in rat liver microsomes

    Directory of Open Access Journals (Sweden)

    Pranali G Patil

    2015-01-01

    Full Text Available Organic solvents used for solubilization of the substrates/NCEs are known to affect the activity of cytochrome P450 enzymes. Further, this effect varies with the solvents used, the substrates and CYP450 isoforms in question. In the present study, we have investigated the effect of ten commonly used water miscible organic solvents (methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, dimethyl sulphoxide, N,N-dimethyl formamide, dioxane and polyethylene glycol 400 on p-nitrophenol hydroxylase activity at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. All the solvents studied showed concentration dependent inhibition of the p-nitrophenol hydroxylase activity except acetonitrile which showed activation of the activity at concentration range studied. Out of ten solvents studied, dioxane was found to be the most inhibitory solvent (inhibition >90% at 0.25% v/v concentration. Overall, solvents like dimethyl sulphoxide, dimethyl formamide and dioxane appeared to be unsuitable for characterizing p-nitrophenol hydroxylase (CYP2E1-mediated reactions due to a high degree of inhibition. On the other hand, methanol and acetonitrile at concentrations <0.5% v/v appeared to be appropriate solvents for substrate solubilization while evaluating CYP2E1-mediated catalysis. The results of this study imply that caution should be exercised while choosing solvents for dissolution of substrate during enzyme studies in liver microsomes.

  14. Effect of water-miscible organic solvents on CYP450-mediated metoprolol and imipramine metabolism in rat liver microsomes

    Directory of Open Access Journals (Sweden)

    T S Shah

    2015-01-01

    Full Text Available The catalytic activity of cytochrome P450 enzymes is known to be affected by presence of organic solvents in in vitro assays. However, these effects tend to be variable and depend on the substrate and CYP450 isoform in question. In the present study, we have investigated effect of ten water miscible organic solvents (methanol, ethanol, propanol, isopropanol, acetone, acetonitrile, dimethylsulphoxide, dimethylformamide, dioxane and PEG400 on water soluble substrates of CYP450, metoprolol and imipramine, at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. Organic solvents studied had a concentration dependent inhibitory effect on the metoprolol and imipramine metabolism activity. Metoprolol metabolism was found to be more susceptible to the organic solvents, almost all the ten solvents had more or less inhibitory effect compared to imipramine metabolism. Except acetone, PEG400 and dimethylsulphoxide, all solvents had ~50% inhibition of total metoprolol metabolism activity, while in case of imipramine metabolism activity, only n-propanol, isopropanol and PEG400 had ~50% inhibition at 1% v/v. Interestingly, methanol, dimethylsulphoxide and acetonitrile had negligible effect on the imipramine metabolism (less than 10% inhibition at 1% v/v while, total metoprolol metabolism activity was substantially inhibited by these solvents (MeOH 52%, DMSO 29% and ACN 47% at 1% v/v. In both cases, dioxane was found to be the most inhibitory solvent (~90% inhibition at 1% v/v.

  15. Electro-driven extraction of inorganic anions from water samples and water miscible organic solvents and analysis by ion chromatography.

    Science.gov (United States)

    Nojavan, Saeed; Bidarmanesh, Tina; Memarzadeh, Farkhondeh; Chalavi, Soheila

    2014-09-01

    A simple electromembrane extraction (EME) procedure combined with ion chromatography (IC) was developed to quantify inorganic anions in different pure water samples and water miscible organic solvents. The parameters affecting extraction performance, such as supported liquid membrane (SLM) solvent, extraction time, pH of donor and acceptor solutions, and extraction voltage were optimized. The optimized EME conditions were as follows: 1-heptanol was used as the SLM solvent, the extraction time was 10 min, pHs of the acceptor and donor solutions were 10 and 7, respectively, and the extraction voltage was 15 V. The mobile phase used for IC was a combination of 1.8 mM sodium carbonate and 1.7 mM sodium bicarbonate. Under these optimized conditions, all anions had enrichment factors ranging from 67 to 117 with RSDs between 7.3 and 13.5% (n = 5). Good linearity values ranging from 2 to 1200 ng/mL with coefficients of determination (R(2) ) between 0.987 and 0.999 were obtained. The LODs of the EME-IC method ranged from 0.6 to 7.5 ng/mL. The developed method was applied to different samples to evaluate the feasibility of the method for real applications.

  16. Hot melt extruded amorphous solid dispersion of posaconazole with improved bioavailability: investigating drug-polymer miscibility with advanced characterisation.

    Science.gov (United States)

    Fule, Ritesh; Amin, Purnima

    2014-01-01

    Invasive antifungal infections are reasons for morbidity and mortality in immunogenic patients worldwide. Posaconazole is a most promising antifungal agent against all types of invasive infections with high % of cure rate. The marketed suspension formulation has low bioavailability and is needed to be taken with food. In this paper, PCZ hot melt extruded amorphous solid dispersion (SD) with immediate release and improved bioavailability was prepared using Soluplus (Sol) as primary carrier for solubilization. Surfactants such as PEG 400, Lutrol F27, Lutrol F68, and TPGS are also used in combination with Soluplus to improve the physicochemical performance of the formulation when it comes in contact with GI (gastrointestinal) fluid. Drug-polymer miscibility of SD was investigated using advanced techniques. In the in vivo study, the AUC(0-72) and C(max) of PCZ/Soluplus were 11.5 and 11.74 time higher than those of pure PCZ. The formulation of the extrudate SD had an AUC(0-72) and C(max) higher than those with the commercial capsule (Noxafil). Molecular dynamic (MD) simulation studies were carried out using in silico molecular modelling to understand the drug-polymer intermolecular behaviour. The results of this research ensure enhanced dissolution and bioavailability of the solid dispersion of PCZ prepared by HME compared with the PCZ suspension.

  17. KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

    Energy Technology Data Exchange (ETDEWEB)

    Gies, D. R.; Matson, R. A.; Guo, Z.; Lester, K. V. [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States); Orosz, J. A. [Department of Astronomy, San Diego State University, San Diego, CA 92182-1221 (United States); Peters, G. J., E-mail: gies@chara.gsu.edu, E-mail: rmatson@chara.gsu.edu, E-mail: guo@chara.gsu.edu, E-mail: lester@chara.gsu.edu, E-mail: jorosz@mail.sdsu.edu, E-mail: gjpeters@mucen.usc.edu [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States)

    2015-12-15

    Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

  18. Binary/BCD-to-ASCII data converter

    Science.gov (United States)

    Miller, A. J.

    1977-01-01

    Converter inputs multiple precision binary words, converts data to multiple precision binary-coded decimal, and routes data back to computer. Converter base can be readily changed without need for new gate structure for each base changeover.

  19. Binary stars in the RAVE survey

    Directory of Open Access Journals (Sweden)

    Zwitter T.

    2012-02-01

    Full Text Available We searched the sample of RAVE survey spectra for both types of spectroscopic binary stars in order to estimate their number in the sample and perform a study on newly discovered binaries.

  20. Small Multiples with Gaps.

    Science.gov (United States)

    Meulemans, Wouter; Dykes, Jason; Slingsby, Aidan; Turkay, Cagatay; Wood, Jo

    2017-01-01

    Small multiples enable comparison by providing different views of a single data set in a dense and aligned manner. A common frame defines each view, which varies based upon values of a conditioning variable. An increasingly popular use of this technique is to project two-dimensional locations into a gridded space (e.g. grid maps), using the underlying distribution both as the conditioning variable and to determine the grid layout. Using whitespace in this layout has the potential to carry information, especially in a geographic context. Yet, the effects of doing so on the spatial properties of the original units are not understood. We explore the design space offered by such small multiples with gaps. We do so by constructing a comprehensive suite of metrics that capture properties of the layout used to arrange the small multiples for comparison (e.g. compactness and alignment) and the preservation of the original data (e.g. distance, topology and shape). We study these metrics in geographic data sets with varying properties and numbers of gaps. We use simulated annealing to optimize for each metric and measure the effects on the others. To explore these effects systematically, we take a new approach, developing a system to visualize this design space using a set of interactive matrices. We find that adding small amounts of whitespace to small multiple arrays improves some of the characteristics of 2D layouts, such as shape, distance and direction. This comes at the cost of other metrics, such as the retention of topology. Effects vary according to the input maps, with degree of variation in size of input regions found to be a factor. Optima exist for particular metrics in many cases, but at different amounts of whitespace for different maps. We suggest multiple metrics be used in optimized layouts, finding topology to be a primary factor in existing manually-crafted solutions, followed by a trade-off between shape and displacement. But the rich range of possible

  1. Preparation and characterization of polymer blends of NC and GAP-TPE%NC/GAP-TPE共混聚合物的制备和性能研究

    Institute of Scientific and Technical Information of China (English)

    左海丽; 肖乐勤; 菅晓霞; 周伟良

    2011-01-01

    A series of blends of energetic thermoplastic polyurethane( GAP-TPE)and Nitrocellulose( NC) were prepared by the way of chain extension,blend and aging. The structures of the blends were analyzed by means of FT1R spectroscopy, wide-angle Xray diffraction,and scanning electron microscopy. The compatibility and properties of the blends were characterized by dynamic mechanical analysis( DMA)and tensile testing. It suggests that nitrocellulose molecules penetrate into the polyurethane and interrupt the intra-hydrogen bonding between the hard and soft segments. The results indicate that the blended sheets exhibited good miscibility. The tensile strength increased with an increase of NC content. The blends NC/GAP-TPE having 5%~20% NC exhibited a significant increase from 10.4 Mpa to 20.4 Mpa for tensile strength ,49% increased.%采用扩链后共混再熟化的方法,制备了1组不同组成的硝化棉(NC)/含能热塑性弹性体(GAP-TPE)共混聚合物.采用红外光谱(FTIR)和X射线衍射(XRD)表征NC/GAP-TPE共混物的结构,扫描电镜(SEM)观察共混物的断面,动态热机械分析(DMA)测定共混物的玻璃化转变,运用拉伸实验研究不同配比NC/GAP-TPE共混物的力学性能.结果表明,NC和GAP-TPE分子间存在氢键相互作用.NC均匀分散在GAP-TPE基体中,不同配比的NC/GAP-TPE共混物均存在1个玻璃化温度,二者之间具有较好的相容性.当NC含量从5%到20%变化时,共混试样的拉伸强度从10.4 MPa增加至20.4 MPa,提高了49%.

  2. Closing the Gap

    DEFF Research Database (Denmark)

    Tamke, Martin; Kobiella, Olaf

    2007-01-01

    The e4d design series is looking for an innovative use of digital technology in architectural education to overcome the gap between design development and the acquisition of digital skills. Digital design approaches include multimedia technology, the crossover of analogue and digital techniques......, rapid-prototyping, visualization, and the presentation in artistic movies. Over the past two years a problem- based design approach was developed, which enabled students to learn digital and architectural skills simultaneously and efficiently. The educational concept consisted generally of four steps......, which, though independent of each other, are determined by questions of the ongoing design process. The first step consists of an abstract or subjective research phase; in the second step the findings are transferred into dynamic spatial structures. Later, the detected qualities are used to develop...

  3. The GAP-TPC

    CERN Document Server

    Rossi, B; Boiano, A; Catalanotti, S; Cocco, A G; Covone, G; Di Meo, P; Longo, G; Vanzanella, A; Walker, S; Wang, H; Wang, Y; Fiorillo, G

    2016-01-01

    Several experiments have been conducted worldwide, with the goal of observing low-energy nuclear recoils induced by WIMPs scattering off target nuclei in ultra-sensitive, low-background detectors. In the last few decades noble liquid detectors designed to search for dark matter in the form of WIMPs have been extremely successful in improving their sensitivities and setting the best limits. One of the crucial problems to be faced for the development of large size (multi ton-scale) liquid argon experiments is the lack of reliable and low background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline performance at 87 K rule them out as a possible candidate for photosensors. We propose a brand new concept of liquid argon-based detector for direct dark matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber (GAP-TPC) optimized in terms of residual radioactivity of the photosensors, energy and spatial resolution, light and charge collection efficiency

  4. The Gap-Tpc

    Science.gov (United States)

    Rossi, B.; Anastasio, A.; Boiano, A.; Catalanotti, S.; Cocco, A. G.; Covone, G.; Di Meo, P.; Longo, G.; Vanzanella, A.; Walker, S.; Wang, H.; Wang, Y.; Fiorillo, G.

    2016-02-01

    Several experiments have been conducted worldwide, with the goal of observing low-energy nuclear recoils induced by WIMPs scattering off target nuclei in ultra-sensitive, low-background detectors. In the last few decades noble liquid detectors designed to search for dark matter in the form of WIMPs have been extremely successful in improving their sensitivities and setting the best limits. One of the crucial problems to be faced for the development of large size (multi ton-scale) liquid argon experiments is the lack of reliable and low background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline performance at 87 K rule them out as a possible candidate for photosensors. We propose a brand new concept of liquid argon-based detector for direct dark matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber (GAP-TPC) optimized in terms of residual radioactivity of the photosensors, energy and spatial resolution, light and charge collection efficiency.

  5. Closing the Gap

    DEFF Research Database (Denmark)

    Tamke, Martin; Kobiella, Olaf

    2007-01-01

    The e4d design series is looking for an innovative use of digital technology in architectural education to overcome the gap between design development and the acquisition of digital skills. Digital design approaches include multimedia technology, the crossover of analogue and digital techniques...... architectural projects can be discussed; in addition, a competent monitoring of the process and outcome of innovative and efficient design strategies in architectural and pedagogical aspect is included......., rapid-prototyping, visualization, and the presentation in artistic movies. Over the past two years a problem- based design approach was developed, which enabled students to learn digital and architectural skills simultaneously and efficiently. The educational concept consisted generally of four steps...

  6. Gaps in Political Interest

    DEFF Research Database (Denmark)

    Robison, Joshua

    2015-01-01

    sought to measure respondents’ general interest in politics by asking them how often they follow public affairs. In this article, we uncover novel sources of measurement error concerning this question. We first show that other nationally representative surveys that frequently use this item deliver......Political interest fundamentally influences political behavior, knowledge, and persuasion (Brady, Verba, & Schlozman, 1995; Delli Carpini & Keeter, 1996; Luskin, 1990; Zukin, Andolina, Keeter, Jenkins, & Delli Carpini, 2006). Since the early 1960s, the American National Election Studies (ANES) has...... drastically higher estimates of mass interest. We then use a survey experiment included on a wave of the ANES’ Evaluating Government and Society Surveys (EGSS) to explore the influence of question order in explaining this systemic gap in survey results. We show that placing batteries of political...

  7. The M Dwarf Eclipsing Binary CU Cancri

    Science.gov (United States)

    Wilson, R. E.; Pilachowski, C. A.; Terrell, Dirk

    2017-02-01

    Spectral features, radial velocities, elemental abundance estimates, other spectral data, and BVIC light curves are reported for the double-M dwarf eclipsing binary CU Cancri—a good target for a radius check versus the Zero Age Main Sequence (ZAMS) due to the low component masses and corresponding very slow evolutionary expansion. The estimate of [Fe/H] is about 0.4, although continuum placement and other difficulties due to line crowding introduce the usual uncertainties for red dwarfs. Detection of the Li i λ6707 line was attempted, with an estimated upper limit of 50 mÅ. Spectral and photometric indicators of stellar activity are described and illustrated. Other objectives were to measure the stellar radii via simultaneous velocity and light-curve solutions of earlier and new data while also improving the ephemeris by filling gaps in timewise coverage with the new velocities and eclipse data from the new light curves. The radii from our solutions agree within about 2% with those from Ribas, being slightly larger than expected for most estimates of the ZAMS. Some aspects of the red dwarf radius anomaly are briefly discussed. Evolution tracks show only very slight age-related expansion for masses near those in CU Cnc. Such expansion could be significant if CU Cnc were similar in age to the Galaxy, but then its Galactic velocity components should be representative of Population II, and they are not.

  8. Bayesian analysis of binary sequences

    Science.gov (United States)

    Torney, David C.

    2005-03-01

    This manuscript details Bayesian methodology for "learning by example", with binary n-sequences encoding the objects under consideration. Priors prove influential; conformable priors are described. Laplace approximation of Bayes integrals yields posterior likelihoods for all n-sequences. This involves the optimization of a definite function over a convex domain--efficiently effectuated by the sequential application of the quadratic program.

  9. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, Ivan I., E-mail: iis@gao.spb.ru [Pulkovo Observatory of the Russian Academy of Sciences, Pulkovskoje ave. 65, St. Petersburg 196140 (Russian Federation)

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  10. A Galactic Binary Detection Pipeline

    Science.gov (United States)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  11. The Meritfactor of Binary Seqences

    DEFF Research Database (Denmark)

    Høholdt, Tom

    1999-01-01

    Binary sequences with small aperiodic correlations play an important role in many applications ranging from radar to modulation and testing of systems. Golay(1977) introduced the merit factor as a measure of the goodness of the sequence and conjectured an upper bound for this. His conjecture is s...

  12. Eccentricity distribution of wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+-0.02 and the eccentricity distribution can be modeled as f(e) ~= 1.2 e + 0.4. However, wide binaries containing inner subsystems, i.e. triple or higher-order multiples, have significantly smaller eccentricities with the average e = 0.52+-0.05 and the peak at e ~ 0.5. We find that the catalog of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentr...

  13. Coevolution of binaries and circumbinary gaseous discs

    Science.gov (United States)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  14. Formation and evolution of compact binaries

    NARCIS (Netherlands)

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  15. The Adaptation Finance Gap Report

    DEFF Research Database (Denmark)

    UNEP’s Adaptation Gap Report series focuses on Finance, Technology and Knowledge gaps in climate change adaptation. It compliments the Emissions Gap Report series, and explores the implications of failing to close the emissions gap. The report builds on a 2014 assessment by the United Nations...... Environment Programme (UNEP), which laid out the concept of ‘adaptation gaps’ and outlined three such gaps: technology, finance and knowledge. The 2016 Adaptation Gap Report assesses the difference between the financial costs of adapting to climate change in developing countries and the amount of money...... actually available to meet these costs – a difference known as the “adaptation finance gap”. Like the 2014 report, the 2016 report focuses on developing countries, where adaptation capacity is often the lowest and needs the highest, and concentrates on the period up to 2050. The report identifies trends...

  16. Understanding the Tax Gap1

    OpenAIRE

    Mazur, Mark J.; Plumley, Alan H.

    2007-01-01

    The Tax Gap is defined as the difference between the amount of tax imposed by the Tax Code and the amount that is reported and paid with timely filed returns. For the federal government, the gross tax gap is estimated at $345 billion for Tax Year 2001 (after the collection of late and enforced payments, the net tax gap is estimated at $290 billion for Tax Year 2001). This paper explains the concept of the tax gap, discusses how it is estimated, and points out some limitations with the estimates.

  17. Gravitational Microlensing of Binary and Binary and Multiple Stars

    Science.gov (United States)

    Cherepashchuk, A. M.

    1995-08-01

    Recent observations of the effect of microlensing of stars of large Magellanic Clouds by dark bodies of Galactic Halo have led to the discovery of new population in our galaxy - dark bodies with amsses ~ 0.1 M(sun). As a consequence, astronomers have gained a unique possibility of using gravitational microlensing as an effective extraterestrial telescope with extremely high angular resolution. Application of this to binary stars is discussed. of particular interest is to apply microlensing to search for planetary stars . Planets and stars move about the center of gravity of the system , so the appaarent motion of a star in nonuniform and the light curve is asymetrical and colour dependent. This allows to determin basic parameters of binary system

  18. Permutation Entropy for Random Binary Sequences

    Directory of Open Access Journals (Sweden)

    Lingfeng Liu

    2015-12-01

    Full Text Available In this paper, we generalize the permutation entropy (PE measure to binary sequences, which is based on Shannon’s entropy, and theoretically analyze this measure for random binary sequences. We deduce the theoretical value of PE for random binary sequences, which can be used to measure the randomness of binary sequences. We also reveal the relationship between this PE measure with other randomness measures, such as Shannon’s entropy and Lempel–Ziv complexity. The results show that PE is consistent with these two measures. Furthermore, we use PE as one of the randomness measures to evaluate the randomness of chaotic binary sequences.

  19. Measuring the Gap

    Directory of Open Access Journals (Sweden)

    Xinshu She MD, MPH

    2016-02-01

    Full Text Available China is a large country where rapid development is accompanied by growing inequalities. How economic inequalities translate to health inequalities is unknown. Baseline health assessment is lacking among rural Chinese children. We aimed at assessing baseline student health of rural Chinese children and comparing them with those of urban children of similar ages. A cross-sectional study was conducted using the 2003 Global School-Based Student Health Survey among 100 students Grade 4 to 6 from rural Guizhou, China. Results were summarized and compared with public data from urban Beijing using multivariate logistic regression models. Rural children are more likely to not wash their hands before a meal (odds ratio [OR] = 5.71, P .05. Rural parents are more likely to not know their children’s whereabouts (OR = 1.81, P < .05. Rural children are more than 4 times likely to have serious injuries (OR = 4.64, P < .01 and to be bullied (OR = 4.01, P < .01. In conclusion, school-age rural Chinese children exhibit more health risk behaviors and fewer protective factors at baseline compared to their urban counterparts. Any intervention aimed at improving child health should take this distributive gap into consideration.

  20. Measuring the Gap

    Science.gov (United States)

    She, Xinshu; Zhao, Deqing; Scholnick, Jenna

    2016-01-01

    China is a large country where rapid development is accompanied by growing inequalities. How economic inequalities translate to health inequalities is unknown. Baseline health assessment is lacking among rural Chinese children. We aimed at assessing baseline student health of rural Chinese children and comparing them with those of urban children of similar ages. A cross-sectional study was conducted using the 2003 Global School-Based Student Health Survey among 100 students Grade 4 to 6 from rural Guizhou, China. Results were summarized and compared with public data from urban Beijing using multivariate logistic regression models. Rural children are more likely to not wash their hands before a meal (odds ratio [OR] = 5.71, P suicidal ideation in the past year (OR = 0.68, P > .05). Rural parents are more likely to not know their children’s whereabouts (OR = 1.81, P bullied (OR = 4.01, P < .01). In conclusion, school-age rural Chinese children exhibit more health risk behaviors and fewer protective factors at baseline compared to their urban counterparts. Any intervention aimed at improving child health should take this distributive gap into consideration. PMID:27335999

  1. Populating the Galaxy with close Be binaries

    CERN Document Server

    Kiel, P D; Murray, J R; Hayasaki, K

    2007-01-01

    Be/X-ray binaries comprise roughly two-thirds of the high-mass X-ray binaries (HMXBs), which is a class of X-ray binaries that results from the high mass of the companion or donor star (> 10 solar masses). Currently the formation and evolution of X-ray producing Be binaries is a matter of great debate. Modelling of these systems requires knowledge of Be star evolution and also consideration of how the evolution changes when the star is in close proximity to a companion. Within this work we complete a full population synthesis study of Be binaries for the Galaxy. The results for the first time match aspects of the observational data, most notably the observed upper limit to the period distribution. We conclude that greater detailed studies on the evolution of Be stars within X-ray binaries needs to be completed, so that rapid binary evolution population synthesis packages may best evolve these systems.

  2. A poromechanical model for coal seams saturated with binary mixtures of CH4 and CO2

    Science.gov (United States)

    Nikoosokhan, Saeid; Vandamme, Matthieu; Dangla, Patrick

    2014-11-01

    Underground coal bed reservoirs naturally contain methane which can be produced. In parallel of the production of this methane, carbon dioxide can be injected, either to enhance the production of methane, or to have this carbon dioxide stored over geological periods of time. As a prerequisite to any simulation of an Enhanced Coal Bed Methane recovery process (ECBM), we need state equations to model the behavior of the seam when cleats are saturated with a miscible mixture of CH4 and CO2. This paper presents a poromechanical model of coal seams exposed to such binary mixtures filling both the cleats in the seam and the porosity of the coal matrix. This model is an extension of a previous work which dealt with pure fluid. Special care is dedicated to keep the model consistent thermodynamically. The model is fully calibrated with a mix of experimental data and numerical data from molecular simulations. Predicting variations of porosity or permeability requires only calibration based on swelling data. With the calibrated state equations, we predict numerically how porosity, permeability, and adsorbed amounts of fluid vary in a representative volume element of coal seam in isochoric or oedometric conditions, as a function of the pressure and of the composition of the fluid in the cleats.

  3. Close supermassive binary black holes

    Science.gov (United States)

    Gaskell, C. Martin

    2010-01-01

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive blackhole binary (SMB). The AGN J1536+0441 (=SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that 1536+044 is an example of line emission from a disc. If this is correct, the lack of clear optical spectral evidence for close SMBs is significant and argues either that the merging of close SMBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  4. Desktop setup for binary holograms

    Science.gov (United States)

    Ginter, Olaf; Rothe, Hendrik

    1996-08-01

    Binary gratings as holograms itself or as photographic masking tools for further fabrication steps can fulfill a lot of applications. The commonly used semiconductor technologies for direct writing of high resolution structures are often too expensive. On the other hand computer plots at a reasonable price with photographic reduction do not meet the needs of precision e.g. for interferometric inspection. The lack of cheap and reliable instruments for direct writing in an appropriate resolution is still a problem in fabricating synthetic holograms. Using off-the-shelf components a direct writing plotter for binary patterns can be built at moderate costs. Typical design rules as well as experimental results are given and the final setup is introduced.

  5. Slim Sets of Binary Trees

    CERN Document Server

    Grünewald, Stefan

    2010-01-01

    A classical problem in phylogenetic tree analysis is to decide whether there is a phylogenetic tree $T$ that contains all information of a given collection $\\cP$ of phylogenetic trees. If the answer is "yes" we say that $\\cP$ is compatible and $T$ displays $\\cP$. This decision problem is NP-complete even if all input trees are quartets, that is binary trees with exactly four leaves. In this paper, we prove a sufficient condition for a set of binary phylogenetic trees to be compatible. That result is used to give a short and self-contained proof of the known characterization of quartet sets of minimal cardinality which are displayed by a unique phylogenetic tree.

  6. Mass transfer between binary stars

    Science.gov (United States)

    Modisette, J. L.; Kondo, Y.

    1980-01-01

    The transfer of mass from one component of a binary system to another by mass ejection is analyzed through a stellar wind mechanism, using a model which integrates the equations of motion, including the energy equation, with an initial static atmosphere and various temperature fluctuations imposed at the base of the star's corona. The model is applied to several situations and the energy flow is calculated along the line of centers between the two binary components, in the rotating frame of the system, thereby incorporating the centrifugal force. It is shown that relatively small disturbances in the lower chromosphere or photosphere can produce mass loss through a stellar wind mechanism, due to the amplification of the disturbance propagating into the thinner atmosphere. Since there are many possible sources of the disturbance, the model can be used to explain many mass ejection phenomena.

  7. PhoneGap for enterprise

    CERN Document Server

    Shotts, Kerri

    2014-01-01

    This book is intended for developers who wish to use PhoneGap to develop useful, rich, secure mobile applications for their enterprise environment. The book assumes you have working knowledge of PhoneGap, HTML5, CSS3, and JavaScript, and a reasonable understanding of networking and n-tier architectures.

  8. GAP Analysis. Bulletin Number 11

    Science.gov (United States)

    2002-01-01

    in 2002 ( ESSB • Creation of a stewardship map is central to GAP’s analysis 6400) that authorizes a comprehensive review to identify the state’s method...governments and their consultants. "Washington State Law ESSB 6400 can be accessed at www.leg.wa.gov/pubfbillinfo/2001-02/Senate, January 10, 2003. Gap

  9. Classification with binary gene expressions

    OpenAIRE

    Tuna, Salih; Niranjan, Mahesan

    2009-01-01

    Microarray gene expression measurements are reported, used and archived usually to high numerical precision. However, properties of mRNA molecules, such as their low stability and availability in small copy numbers, and the fact that measurements correspond to a population of cells, rather than a single cell, makes high precision meaningless. Recent work shows that reducing measurement precision leads to very little loss of information, right down to binary levels. In this paper we show how p...

  10. Binary neuron with optical devices

    Science.gov (United States)

    Degeratu, Vasile; Degeratu, Ştefania; Şchiopu, Paul; Şchiopu, Carmen

    2009-01-01

    In this paper the authors present a model of binary neuron, a model of McCulloch-Pitts neuron with optical devices. This model of neuron can be implemented not only in the optic integrated circuits but also in the classic optical circuits it being cheap and immune not only into electromagnetic fields but also into any kind of radiation. The transfer speed of information through the neuron is very higher, it being limited only by the light speed from the received medium.

  11. Components of the Belief Gap

    Directory of Open Access Journals (Sweden)

    Cecilie Gaziano

    2014-01-01

    Full Text Available Knowledge gap research focuses on education as an indicator of socioeconomic status (SES. Belief gap research centers on ideology as potentially more powerful than education in comparing sociopolitical groups with scientifically established knowledge and groups with opposing beliefs accepted on faith. This study examined the relationship between education and ideology to understand belief gaps better. The study used 2008 American National Election Study (ANES data to compare conservatives, moderates, and liberals by education on religiosity, child rearing values, opinionation, need for cognition, orientation toward politics, and mass media access and use. Although liberals tended to be more educated than conservatives overall, better-educated conservatives had the highest household incomes and were a much larger group. No known knowledge gap studies have reported results on one group characterized by high education and an opposing group distinguished by a different indicator of SES. Reformulations of the belief gap hypothesis are offered.

  12. Be/X-ray binaries

    CERN Document Server

    Reig, Pablo

    2011-01-01

    The purpose of this work is to review the observational properties of Be/X-ray binaries. The open questions in Be/X-ray binaries include those related to the Be star companion, that is, the so-called "Be phenomenon", such as, timescales associated to the formation and dissipation of the equatorial disc, mass-ejection mechanisms, V/R variability, and rotation rates; those related to the neutron star, such as, mass determination, accretion physics, and spin period evolution; but also, those that result from the interaction of the two constituents, such as, disc truncation and mass transfer. Until recently, it was thought that the Be stars' disc was not significantly affected by the neutron star. In this review, I present the observational evidence accumulated in recent years on the interaction between the circumstellar disc and the compact companion. The most obvious effect is the tidal truncation of the disc. As a result, the equatorial discs in Be/X-ray binaries are smaller and denser than those around isolat...

  13. Binding of Solvent Molecules to a Protein Surface in Binary Mixtures Follows a Competitive Langmuir Model.

    Science.gov (United States)

    Kulschewski, Tobias; Pleiss, Jürgen

    2016-09-06

    The binding of solvent molecules to a protein surface was modeled by molecular dynamics simulations of of Candida antarctica (C. antarctica) lipase B in binary mixtures of water, methanol, and toluene. Two models were analyzed: a competitive Langmuir model which assumes identical solvent binding sites with a different affinity toward water (KWat), methanol (KMet), and toluene (KTol) and a competitive Langmuir model with an additional interaction between free water and already bound water (KWatWat). The numbers of protein-bound molecules of both components of a binary mixture were determined for different compositions as a function of their thermodynamic activities in the bulk phase, and the binding constants were simultaneously fitted to the six binding curves (two components of three different mixtures). For both Langmuir models, the values of KWat, KMet, and KTol were highly correlated. The highest binding affinity was found for methanol, which was almost 4-fold higher than the binding affinities of water and toluene (KMet ≫ KWat ≈ KTol). Binding of water was dominated by the water-water interaction (KWatWat). Even for the three protein surface patches of highest water affinity, the binding affinity of methanol was 2-fold higher than water and 8-fold higher than toluene (KMet > KWat > KTol). The Langmuir model provides insights into the protein destabilizing mechanism of methanol which has a high binding affinity toward the protein surface. Thus, destabilizing solvents compete with intraprotein interactions and disrupt the tertiary structure. In contrast, benign solvents such as water or toluene have a low affinity toward the protein surface. Water is a special solvent: only few water molecules bind directly to the protein; most water molecules bind to already bound water molecules thus forming water patches. A quantitative mechanistic model of protein-solvent interactions that includes competition and miscibility of the components contributes a robust basis

  14. Detached cataclysmic variables are crossing the orbital period gap

    CERN Document Server

    Zorotovic, Monica; Parsons, Steven G; Gänsicke, Boris T; Hardy, Adam; Agurto-Gangas, Carolina; Gómez-Morán, Ada Nebot; Rebassa-Mansergas, Alberto; Schwope, Axel D

    2016-01-01

    A central hypothesis in the theory of cataclysmic variable (CV) evolution is the need to explain the observed lack of accreting systems in the ~2-3 h orbital period range, known as the period gap. The standard model, disrupted magnetic braking (DMB), reproduces the gap by postulating that CVs transform into inconspicuous detached white dwarf (WD) plus main sequence (MS) systems, which no longer resemble CVs. However, observational evidence for this standard model is currently indirect and thus this scenario has attracted some criticism throughout the last decades. Here we perform a simple but exceptionally strong test of the existence of detached CVs (dCVs). If the theory is correct dCVs should produce a peak in the orbital period distribution of detached close binaries consisting of a WD and an M4-M6 secondary star. We measured six new periods which brings the sample of such binaries with known periods below 10 h to 52 systems. An increase of systems in the ~2-3 h orbital period range is observed. Comparing ...

  15. Visual Binaries in the Orion Nebula Cluster

    CERN Document Server

    Reipurth, Bo; Connelley, Michael S; Bally, John

    2007-01-01

    We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is signifi...

  16. A Novel Adaptive Approach to Process Binary Fingerprint Images Using Directional Morphological Operations

    Institute of Scientific and Technical Information of China (English)

    Jin Qi

    2009-01-01

    An adaptive algorithm for removing false ridges, bridges and filling gaps in binary fingerprint images based on morphological operations is presented. A novel procedure for structuring elements design based on the specific fingerprint characteristic is described. Using the images from FVC2000 database, we have compared our method proposed here with the approach proposed by other ones. The Experimental results have demonstrated the efficiency of our method.

  17. Miscibility,Thermal Stability,Rheological and Mechanical Properties of Blends Derived from Polysulfone Oligomer and Poly (phthalazinone ether sulfone ketone)

    Institute of Scientific and Technical Information of China (English)

    Guimei WANG; Xigao JIAN; Gongxiong LIAO; Lihao WU

    2004-01-01

    Poly(phthalazinone ether sulfone ketone) (PPESK) was melt blended with bisphenol-A polysulfone oligomer (O-PSF)to produce a thermoplastic polymer blends. The miscibility, thermal stability, theological and mechanical properties of the blends were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC),thermogravimetric analysis (TGA) and capillary rheometry. The blends showed single Tg over the composition range and possess homogeneous microstructure. The addition of O-PSF slightly affected the thermal properties of the blends. PSF oligomer, as a processing aid, could markedly improve the processability of the PPESK. In addition, the mechanical properties of the blends were increased, to some degree, by adding O-PSF.

  18. THERMAL PROPERTY, MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(3-HYDROXYBUTYRATE-co 3-YDROXYHEXANOATE) AND POLY(BUTYLENE SUCCINATE-ADIPATE) (PHBHHX/PBSA) BLENDS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/20 to 20/80 by melt mixing method. Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMA), polarizing optical microscopy (POM) and wide angle X-ray diffractometer (WAXD) were used to study the miscibility and crystallization behavior of PHBHHx/PBSA blends. Experimental results indicate that PHBHHx is immiscible with PBSA as shown by the almost unchanged glass transition temperature and the biphasic melt.

  19. Noncoalescence of sessile drops from different but miscible liquids: hydrodynamic analysis of the twin drop contour as a self-stabilizing traveling wave.

    Science.gov (United States)

    Karpitschka, Stefan; Riegler, Hans

    2012-08-10

    Capillarity always favors drop fusion. Nevertheless, sessile drops from different but completely miscible liquids often do not fuse instantaneously upon contact. Rather, intermediate noncoalescence is observed. Two separate drop bodies, connected by a thin liquid neck, move over the substrate. Supported by new experimental data, a thin film hydrodynamic analysis of this state is presented. Presumably advective and diffusive volume fluxes in the neck region establish a localized and temporarily stable surface tension gradient. This induces a local surface (Marangoni) flow that stabilizes a traveling wave, i.e., the observed moving twin drop configuration. The theoretical predictions are in excellent agreement with the experimental findings.

  20. Non-coalescence of sessile drops from different but miscible liquids: Hydrodynamic analysis of the twin drop contour as self stabilizing, traveling wave

    CERN Document Server

    Karpitschka, Stefan

    2015-01-01

    Capillarity always favors drop fusion. Nevertheless sessile drops from different but completely miscible liquids often do not fuse instantaneously upon contact. Rather, intermediate non-coalescence is observed. Two separate drop bodies, connected by a thin liquid neck move over the substrate. Supported by new experimental data a thin film hydrodynamic analysis of this state is presented. Presumably advective and diffusive volume fluxes in the neck region establish a localized and temporarily stable surface tension gradient. This induces a local surface (Marangoni) flow that stabilizes a traveling wave i.e., the observed moving twin drop configuration. The theoretical predictions are in excellent agreement with the experimental findings.

  1. The fluctuating gap model

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiaobin

    2011-01-15

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T{sub c} in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the

  2. More on gapped Goldstones at finite density: More gapped Goldstones

    CERN Document Server

    Nicolis, Alberto; Piazza, Federico; Rosen, Rachel A

    2013-01-01

    It was recently argued that certain relativistic theories at finite density can exhibit an unconventional spectrum of Goldstone excitations, with gapped Goldstones whose gap is exactly calculable in terms of the symmetry algebra. We confirm this result as well as previous ones concerning gapless Goldstones for non-relativistic systems via a coset construction of the low-energy effective field theory. Moreover, our analysis unveils additional gapped Goldstones, naturally as light as the others, but this time with a model-dependent gap. Their exact number cannot be inferred solely from the symmetry breaking pattern either, but rather depends on the details of the symmetry breaking mechanism--a statement that we explicitly verify with a number of examples. Along the way we provide what we believe to be a particularly transparent interpretation of the so-called inverse-Higgs constraints for spontaneously broken spacetime symmetries.

  3. The Income Gap GROWS Large

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The income gap between regions, urban and rural areas, industries and various social groups is widening in China. The gap, as indicated by the Gini Coefficient, extended beyond an alarming level. A World Bank report said the Gini Coefficient for China surged to 0.47 in 2009, exceeding the "red line" of 0.4. The problems caused by the rising income disparity have been the focus of public attention. Some experts believe that it is high time for China to shrink this income gap. A Xinhua News Agency research team recently analyzed this trend, and published an article in the Economic Information Daily. Edited excerpts follow:

  4. The Income Gap Grows Large

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ The income gap between regions,urban and rural areas,industries and various social groups is widening in China.The gap,as indicated by the Gini Coefficient,extended beyond an alarming level.A World Bank report said the Gini Coefficient for China surged to 0A7 in 2009,exceeding the "red line"of 0.4.The problems caused by the rising income disparity have been the focus of public attention.Some experts believe that it is high time for China to shrink this income gap.

  5. Microlensing Signature of Binary Black Holes

    Science.gov (United States)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  6. Detection of unresolved binaries with multicolor photometry

    CERN Document Server

    Chulkov, D; Malkov, O; Sichevskij, S; Krussanova, N; Mironov, A; Zakharov, A; Kniazev, A

    2016-01-01

    The principal goal of this paper is to specify conditions of detection of unresolved binaries by multicolor photometry. We have developed a method for estimating the critical distance at which an unresolved binary of given mass and age can be detected. The method is applied to the photometric system of the planned Lyra-B spaceborne experiment. We have shown that some types of unresolved binary stars can be discovered and distinguished from single stars solely by means of photometric observations.

  7. Mind the Gap when Data Mining the Ritter-Kolb Cataclysmic Variable Catalogue

    Science.gov (United States)

    Sparks, Warren M.; Sion, Edward M.

    2017-01-01

    The cataclysmic variable (CV) binary consists of a white dwarf primary and a low-mass secondary which overflows its Roche lobe. The Ritter-Kolb catalogue (2003, A&A, 404, 301) is a collection (~1000) of CV binaries and related objects. We have mined this catalogue for CVs with unevolved secondaries whose mass ratio (secondary/primary) is known (~130). A plot of the secondary mass verses the log of the orbital period exhibits the well-known period gap at 2-3 hrs. In addition, this plot shows that the secondary masses just above the period gap are collectively much larger than those just below. The average of the first ten secondary masses above the period is 180% larger than the average below the gap.The disrupted magnetic braking hypothesis (Howell, Nelson, and Rappaport 2001, ApJ, 550, 897 [HNR]) predicts that when the secondary becomes fully convective, the magnetic braking, which has driven the secondary out of thermal equilibrium, stops. In adjusting to thermal equilibrium the secondary shrinks below its Roche lobe and no longer loses mass. The binary system ceases to appear as a CV until gravitational radiation loss brings the secondary back in contact with its Roche lobe. This scenario is at odds with the apparent secondary mass loss across the period gap. Either the secondary continues to lose mass while crossing the period gap or the secondary masses are miscalculated!Magnetic braking causes the secondary to expand or inflate larger than its single star counterpart. Any orbital parameter calculation which assumes a radius-mass relationship based on single main-sequence stars will overestimate the mass of the secondary. We can approximate this mass overestimation from calculations by HNR which take into account the thermal heating from magnetic braking. Using this approximation as a first-order correction to the secondary mass, we replot the deflated secondary mass versus the binary period. The deflated masses immediately above and below the period gap are

  8. Speech perception of noise with binary gains

    DEFF Research Database (Denmark)

    Wang, DeLiang; Kjems, Ulrik; Pedersen, Michael Syskind;

    2008-01-01

    For a given mixture of speech and noise, an ideal binary time-frequency mask is constructed by comparing speech energy and noise energy within local time-frequency units. It is observed that listeners achieve nearly perfect speech recognition from gated noise with binary gains prescribed...... by the ideal binary mask. Only 16 filter channels and a frame rate of 100 Hz are sufficient for high intelligibility. The results show that, despite a dramatic reduction of speech information, a pattern of binary gains provides an adequate basis for speech perception....

  9. Survival of planets around shrinking stellar binaries.

    Science.gov (United States)

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

  10. On the BICM Capacity - Part I: Binary Labelings, Arbitrary Input Distributions, and First-Order Asymptotics

    CERN Document Server

    Alvarado, Alex

    2010-01-01

    In this semitutorial paper (Part I of a two-part paper), the capacity of bit-interleaved coded modulation (BICM) is analyzed. We introduce a general model for BICM which considers all the variables affecting the BICM capacity: the binary labeling, the input distribution, and the signal set. We show that the relation between the BICM capacity and Eb/N0 is not always a one-to-one function, we analyze how to increase the BICM capacity by modifying the input symbol distribution, and we develop first-order asymptotics of the BICM capacity for constellations with arbitrary input distributions, dimensions, mean, variance, and binary labeling. For 8-ary pulse amplitude modulation (PAM) and around Es/N0=0 dB (0.75 bit/symbol), the folded binary code (FBC) results in a higher capacity than the binary reflected gray code (BRGC) and the natural binary code (NBC). For the same SNR, the 1 dB gap between the additive white Gaussian noise (AWGN) capacity and the BICM capacity can be reduced to 0.2 dB if the input symbol dist...

  11. Near-Infrared Polarimetry of the GG Tauri A Binary System

    Science.gov (United States)

    Itoh, Yoichi; Oasa, Yumiko; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Egner, Sebastian; Feldt, Markus; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kuzuhara, Masayuki; Kwon, Jungmi; Matsuo, Taro; McElwain, Michael W.; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suenaga, Takuya; Suto, Hiroshi

    2014-01-01

    A high angular resolution near-infrared image that shows the intensity of polarization for the GG Tau A binary system was obtained with the Subaru Telescope. The image shows a circumbinary disk scattering the light from the central binary. The azimuthal profile of the intensity of polarization for the circumbinary disk is roughly reproduced by a simple disk model with the Henyey-Greenstein phase function and the Rayleigh function, indicating there are small dust grains at the surface of the disk. Combined with a previous observation of the circumbinary disk, our image indicates that the gap structure in the circumbinary disk orbits counterclockwise, but material in the disk orbits clockwise. We propose that there is a shadow caused by material located between the central binary and the circumbinary disk. The separations and position angles of the stellar components of the binary in the past 20 yr are consistent with the binary orbit with a = 33.4 AU and e = 0.34.

  12. Gap Surface Plasmon Waveguide Analysis

    DEFF Research Database (Denmark)

    Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.

    2014-01-01

    Plasmonic waveguides supporting gap surface plasmons (GSPs) localized in a dielectric spacer between metal films are investigated numerically and the waveguiding properties at telecommunication wavelengths are presented. Especially, we emphasize that the mode confinement can advantageously...

  13. Closing the Cybersecurity Skills Gap

    Directory of Open Access Journals (Sweden)

    Rebecca Vogel

    2016-05-01

    Full Text Available The current consensus is that there is a worldwide gap in skills needed for a competent cybersecurity workforce. This skills gap has implications for the national security sector, both public and private. Although the view is that this will take a concerted effort to rectify, it presents an opportunity for IT professionals, university students, and aspirants to take-up jobs in national security national intelligence as well military and law enforcement intelligence. This paper examines context of the issue, the nature of the cybersecurity skills gap, and some key responses by governments to address the problem. The paper also examines the emerging employment trends, some of the employment challenges, and what these might mean for practice. The paper argues that the imperative is to close the cyber skills gap by taking advantage of the window of opportunity, allowing individuals interested in moving into the cybersecurity field to do so via education and training.

  14. Dielectric Function and Critical Point of GeSbTe Pseudo-binary Compound Thin Films

    Science.gov (United States)

    Lee, Hosun; Park, Jun-Woo; Kang, Youn-Seon; Lee, Tae-Yon; Suh, Dong-Seok; Kim, Ki-Joon; Kim, Cheol Kyu; Kang, Yoon Ho; da Silva, Juarez L. F.

    2009-03-01

    We measure the dielectric functions of GeSbTe pseudo-binary thin films by using spectroscopic ellipsometry. We anneal the thin films at various temperatures. According to x-ray diffraction, the as-grown thin films are amorphous and the annealed films have metastable and stable crystalline phases. By using standard critical point model, we obtain the accurate values of the energy gap of the amorphous phase as well as the critical point energies of the crystalline thin films. The critical point energies are compared to the band gap energies determined by the method of linear extrapolation of the optical absorption. As the Sb to Ge atomic ratio increases, the optical (band) gap energy of amorphous (crystalline) phase decreases. Standard critical point fitting show several higher band gaps. The electronic band structures and the dielectric functions of the thin films are calculated by using density functional theory and are compared to the measured ones. The band structure calculations show in stable phase that GeTe, Ge2Sb2Te5, and Ge1Sb2Te4 have indirect gap whereas Ge1Sb4Te7 and Sb2Te3 have direct gap. The measured indirect band gap energies match well with the electronic band structure calculations.

  15. The structures of binary compounds

    CERN Document Server

    Hafner, J; Jensen, WB; Majewski, JA; Mathis, K; Villars, P; Vogl, P; de Boer, FR

    1990-01-01

    - Up-to-date compilation of the experimental data on the structures of binary compounds by Villars and colleagues. - Coloured structure maps which order the compounds into their respective structural domains and present for the first time the local co-ordination polyhedra for the 150 most frequently occurring structure types, pedagogically very helpful and useful in the search for new materials with a required crystal structure. - Crystal co-ordination formulas: a flexible notation for the interpretation of solid-state structures by chemist Bill Jensen. - Recent important advances in unders

  16. Binary stellar mergers with marginally bound ejecta: excretion discs, inflated envelopes, outflows, and their luminous transients

    Science.gov (United States)

    Pejcha, Ondřej; Metzger, Brian D.; Tomida, Kengo

    2016-09-01

    We study mass-loss from the outer Lagrange point (L2) in binary stellar mergers and their luminous transients by means of radiative hydrodynamical simulations. Previously, we showed that for binary mass ratios 0.06 ≲ q ≲ 0.8, synchronous L2 mass-loss results in a radiatively inefficient, dust-forming unbound equatorial outflow. A similar outflow exists irrespective of q if the ratio of the sound speed to the orbital speed at the injection point is sufficiently large, ε ≡ cT/vorb ≳ 0.15. By contrast, for cold L2 mass-loss (ε ≲ 0.15) from binaries with q ≲ 0.06 or q ≳ 0.8, the equatorial outflow instead remains marginally bound and falls back to the binary over tens to hundreds of binary orbits, where it experiences additional tidal torquing and shocking. As the bound gas becomes virialized with the binary, the luminosity of the system increases slowly at approximately constant photosphere radius, causing the temperature to rise. Subsequent evolution depends on the efficiency of radiative cooling. If the bound atmosphere is able to cool efficiently, as quantified by radiative diffusion time being shorter than the advection time (tdiff/tadv ≪ 1), then the virialized gas collapses to an excretion disc, while for tdiff/tadv ≳ 1 an isotropic wind is formed. Between these two extremes, an inflated envelope transports the heat generated near the binary to the surface by meridional flows. In all cases, the radiated luminosity reaches a fraction ˜10-2 to 10-1 of dot{M}v_orb^2/2, where dot{M} is the mass outflow rate. We discuss the implications of our results for transients in the luminosity gap between classical novae and supernovae, such as V1309 Sco and V838 Mon.

  17. pH effects on the complexation, miscibility and radiation-induced crosslinking in poly(acrylic acid)-poly(vinyl alcohol) blends.

    Science.gov (United States)

    Nurkeeva, Zauresh S; Mun, Grigoriy A; Dubolazov, Artem V; Khutoryanskiy, Vitaliy V

    2005-05-23

    The effect of pH on the complexation of poly(acrylic acid) with poly(vinyl alcohol) in aqueous solution, the miscibility of these polymers in the solid state and the possibility for crosslinking the blends using gamma radiation has been studied. It is demonstrated that the complexation ability of poly(vinyl alcohol) with respect to poly(acrylic acid) is relatively low in comparison with some other synthetic non-ionic polymers. The precipitation of interpolymer complexes was observed below the critical pH of complexation (pH(crit1)), which characterizes the transition between a compact hydrophobic polycomplex and an extended hydrophilic interpolymer associate. Films prepared by casting from aqueous solutions at different pH values exhibited a transition from miscibility to immiscibility at a certain critical pH, pH(crit2), above which hydrogen bonding is prevented. It is shown here that gamma radiation crosslinking of solid blends is efficient and only results in the formation of hydrogel films for blends prepared between pH(crit1) and pH(crit2). The yield of the gel fraction and the swelling properties of the films depended on the absorbed radiation dose and the polymer ratio. [Diagram: see text] SEM image of an equimolar PAA-PVA blend cast from a pH 4.6 solution.

  18. Miscibility of dl-α-tocopherol β-glucoside in DPPC monolayer at air/water and air/solid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Neunert, G. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Makowiecki, J.; Piosik, E.; Hertmanowski, R. [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland); Polewski, K. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Martynski, T., E-mail: tomasz.martynski@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland)

    2016-10-01

    The role of newly synthesized tocopherol glycosidic derivative in modifying molecular organization and phase transitions of phospholipid monolayer at the air/water interface has been investigated. Two-component Langmuir films of dl-α-tocopheryl β-D-glucopyranoside (BG) mixed with dipalmitoyl phosphatidylcholine (DPPC) in the whole range of mole fractions were formed at the water surface. An analysis of surface pressure versus mean molecular area (π-A) isotherms and Brewster angle microscope images showed that the presence of BG molecules changes the structure and packing of the DPPC monolayer in a BG concentration dependent manner. BG molecules incorporated into DPPC monolayer inhibit its liquid expanded to liquid condensed phase transition proportionally to the BG concentration. The monolayers were also transferred onto solid substrates and visualized using an atomic force microscope. The results obtained indicate almost complete miscibility of BG and DPPC in the monolayers at surface pressures present in the biological cell membrane (30-35·10{sup -3} N·m{sup -1}) for a BG mole fraction as high as 0.3. This makes the monolayer less packed and more disordered, leading to an increased permeability. The results support our previous molecular dynamics simulation data. - Highlights: • Langmuir films of α-tocopherol derivative with DPPC was studied thermodynamically. • Mixed DPPC/BG films were transferred onto mica substrates for topography imaging by using AFM. • Miscibility of BG/DPPC films at surface pressures present in membranes was observed up to MF = 0.3.

  19. Miscibility, crystallization properties and morphology of PA 6/TLCPa%PA6/TLCPa的相容性、结晶性能及其形貌

    Institute of Scientific and Technical Information of China (English)

    郭鸿俊; 张卓; 蔡勇; 李瑞杰; 王磊; 梅立

    2011-01-01

    Polyamide(PA) 6/thermotropic liquid crystalline polyamide (TLCPa)/in situ composites were prepared by extrusion molding. The miscibility, crystallization properties and morphology of the blends were studied. The results show that TLCPa and PA 6 are well miscible and hydrogen bonds exist between the polymer molecules The involvement of TLCPa in the crystallization process of PA 6 lower the latter's crystallization degree. The size of PA 6 spherulite augments with the increase of TLCPa content. Υcrystal form appears when the TLCPa mass fraction reaches 30.0%. TLCPa forms reinforced fiber with the large slenderness ratio in the PA 6 matrix.%采用挤出成型制备了聚酰胺(PA)6/热致聚酰胺液晶(TLCPa)原位复合材料,研究了共混物的相容性、结晶性能和形貌.结果表明:TLCPa和PA 6具有较好的相容性,并存在分子间氢键作用;TLCPa掺人到PA 6的结晶过程中降低了PA 6的结晶度;PA 6的球晶大小随w(TLCPa)的而增大,当w(TLCPa)为30.0%时,出现γ晶型;TLCPa在PA 6基体中形成长径比较大的增强纤维.

  20. R144 : a very massive binary likely ejected from R136 through a binary-binary encounter

    CERN Document Server

    Oh, Seungkyung; Banerjee, Sambaran

    2013-01-01

    R144 is a recently confirmed very massive, spectroscopic binary which appears isolated from the core of the massive young star cluster R136. The dynamical ejection hypothesis as an origin for its location is claimed improbable by Sana et al. due to its binary nature and high mass. We demonstrate here by means of direct N-body calculations that a very massive binary system can be readily dynamically ejected from a R136-like cluster, through a close encounter with a very massive system. One out of four N-body cluster models produces a dynamically ejected very massive binary system with a mass comparable to R144. The system has a system mass of $\\approx$ 355 Msun and is located at 36.8 pc from the centre of its parent cluster, moving away from the cluster with a velocity of 57 km/s at 2 Myr as a result of a binary-binary interaction. This implies that R144 could have been ejected from R136 through a strong encounter with an other massive binary or single star. In addition, we discuss all massive binaries and sin...

  1. Interacting Jets from Binary Protostars

    CERN Document Server

    Murphy, G C; O'Sullivan, S; Spicer, D; Bacciotti, F; Rosén, A

    2007-01-01

    We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly pa...

  2. The Young Visual Binary Database

    Science.gov (United States)

    Prato, Lisa A.; Avilez, Ian; Allen, Thomas; Zoonematkermani, Saeid; Biddle, Lauren; Muzzio, Ryan; Wittal, Matthew; Schaefer, Gail; Simon, Michal

    2017-01-01

    We have obtained adaptive optics imaging and high-resolution H-band and in some cases K-band spectra of each component in close to 100 young multiple systems in the nearby star forming regions of Taurus, Ophiuchus, TW Hya, and Orion. The binary separations for the pairs in our sample range from 30 mas to 3 arcseconds. The imaging and most of our spectra were obtained with instruments behind adaptive optics systems in order to resolve even the closest companions. We are in the process of determining fundamental stellar and circumstellar properties, such as effective temperature, Vsin(i), veiling, and radial velocity, for each component in the entire sample. The beta version of our database includes systems in the Taurus region and provides plots, downloadable ascii spectra, and values of the stellar and circumstellar properties for both stars in each system. This resource is openly available to the community at http://jumar.lowell.edu/BinaryStars/. In this poster we describe initial results from our analysis of the survey data. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

  3. Millisecond Pulsars in Close Binaries

    CERN Document Server

    Tauris, Thomas M

    2015-01-01

    In this Habilitationsschrift (Habilitation thesis) I present my research carried out over the last four years at the Argelander Institute for Astronomy (AIfA) and the Max Planck Institute for Radio Astronomy (MPIfR). The thesis summarizes my main findings and has been written to fulfill the requirements for the Habilitation qualification at the University of Bonn. Although my work is mainly focused on the topic of millisecond pulsars (MSPs), there is a fairly broad spread of research areas ranging from the formation of neutron stars (NSs) in various supernova (SN) events, to their evolution, for example, via accretion processes in binary and triple systems, and finally to their possible destruction in merger events. The thesis is organized in the following manner: A general introduction to neutron stars and millisecond pulsars is given in Chapter 1. A selection of key papers published in 2011-2014 are presented in Chapters 2-10, ordered within five main research areas (ultra-stripped SNe in close binaries, ma...

  4. Carrying a Torch for Dust in Binary Star Systems

    CERN Document Server

    Cotton, Daniel V; Bott, Kimberly; Kedziora-Chudczer, Lucyna; Bailey, Jeremy

    2016-01-01

    Young stars are frequently observed to host circumstellar disks, within which their attendant planetary systems are formed. Scattered light imaging of these proto-planetary disks reveals a rich variety of structures including spirals, gaps and clumps. Self-consistent modelling of both imaging and multi-wavelength photometry enables the best interpretation of the location and size distribution of disks' dust. Epsilon Sagittarii is an unusual star system. It is a binary system with a B9.5III primary that is also believed to host a debris disk in an unstable configuration. Recent polarimetric measurements of the system with the High Precision Polarimetric Instrument (HIPPI) revealed an unexpectedly high fractional linear polarisation, one greater than the fractional infrared excess of the system. Here we develop a spectral energy distribution model for the system and use this as a basis for radiative transfer modelling of its polarisation with the RADMC-3D software package. The measured polarisation can be repro...

  5. Positronium in solid phases of n-alkane binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zgardzińska, B.; Goworek, T.

    2015-09-08

    Highlights: • Rotator phase in even alkanes C{sub n}H{sub 2n+2} with n ⩽ 20 appears in mixed samples only. • Interlamellar gap width is the same for shorter chain alkane concentration x and 1 − x. • Excess electron trapping diminishes with broadening of alkane chain distribution Δn. - Abstract: Binary mixtures of even-numbered normal alkanes C{sub n}H{sub 2n+2} and C{sub n+2}H{sub 2n+6} with n ⩽ 18 were investigated by positron annihilation spectroscopy. Formation of the rotator phase was observed in mixed structures, while no such a phase in neat alkanes in this range of n was found. Phase diagrams for n = 18 and n = 16 are very similar to the diagrams for binary mixtures of odd-numbered alkanes. The effect of positronium formation with trapped excess electrons weakens with decreasing n, at low n values the time constant of Ps rise contains the component much shorter than 1 h.

  6. Rotation Periods of Wide Binaries in the Kepler Field

    Science.gov (United States)

    Janes, K. A.

    2017-01-01

    In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function (ACF) of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component, in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period–color diagram. Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions, are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapidly than others at the same mass. Finally, using the ACF as a measure of the activity level, I found that while the F, G, and early K stars become less active as their periods increase, there is no correlation between period and activity for the mid K to early M stars.

  7. Tidal disruption events by a massive black hole binary

    Science.gov (United States)

    Ricarte, Angelo; Natarajan, Priyamvada; Dai, Lixin; Coppi, Paolo

    2016-05-01

    Massive black hole binaries (MBHBs) are a natural byproduct of galaxy mergers. Previous studies have shown that flares from stellar tidal disruption events (TDEs) are modified by the presence of a secondary perturber, causing interruptions in the light curve. We study the dynamics of TDE debris in the presence of a milliparsec-separated MBHB by integrating ballistic particle orbits in the time-varying potential of the binary. We find that gaps in the light curve appear when material misses the accretion radius on its first return to pericentre. Subsequent recurrences can be decomposed into `continuous' and `delayed' components, which exhibit different behaviour. We find that this potential can substantially alter the locations of stream self-intersections. When debris is confined to the plane, we find that close encounters with the secondary massive black hole (MBH) leave noticeable signatures on the fallback rate and can result in significant accretion on to the secondary MBH. Tight, equal-mass MBHBs accrete equally, periodically trading the infalling stream.

  8. Rotation Periods of Wide Binaries in the Kepler Field

    CERN Document Server

    Janes, K A

    2016-01-01

    In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period-color diagram. Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapi...

  9. Binary Relations as a Foundation of Mathematics

    NARCIS (Netherlands)

    Kuper, J.; Barendsen, E.; Capretta, V.; Geuvers, H.; Niqui, M.

    2007-01-01

    We describe a theory for binary relations in the Zermelo-Fraenkel style. We choose for ZFCU, a variant of ZFC Set theory in which the Axiom of Foundation is replaced by an axiom allowing for non-wellfounded sets. The theory of binary relations is shown to be equi-consistent ZFCU by constructing a mo

  10. Binary Structure in David Lodge's Novels

    Institute of Scientific and Technical Information of China (English)

    高萍

    2008-01-01

    David Lodge is one of the most renowned modern English writers.He is known for the binary structure in his novels.In this paper,the writer will try to the binary structure in some of his novels to show his reflections on Catholicism and culture conflicts.

  11. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  12. Helium in atmospheres of binary stars

    Energy Technology Data Exchange (ETDEWEB)

    Leushin, V.V. (Rostovskij-na-Donu Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Fiziki)

    The helium abundances were obtained for 25 bright components of binary stars by model atmosphere analysis. The helium abundance for binary stars that lie on the main sequence are larger in the average than in single normal stars. The stars on the Hertzsppung - russel diagram lie at a larger distance from the zero age line than those with normal helium abundance.

  13. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Yungelson, Lev R.

    2006-12-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA. Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  14. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Konstantin A. Postnov

    2014-05-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  15. Bayesian analysis of exoplanet and binary orbits

    OpenAIRE

    Schulze-Hartung, Tim; Launhardt, Ralf; Henning, Thomas

    2012-01-01

    We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A.

  16. Binary Representations of Fingerprint Spectral Minutiae Features

    NARCIS (Netherlands)

    Xu, Haiyun; Veldhuis, Raymond N.J.

    2010-01-01

    A fixed-length binary representation of a fingerprint has the advantages of a fast operation and a small template storage. For many biometric template protection schemes, a binary string is also required as input. The spectral minutiae representation is a method to represent a minutiae set as a fixe

  17. The Evolution of Compact Binary Star Systems.

    Science.gov (United States)

    Postnov, Konstantin A; Yungelson, Lev R

    2014-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  18. Binary Planetary Nebulae Nuclei towards the Galactic Bulge. I. Sample Discovery, Period Distribution and Binary Fraction

    CERN Document Server

    Miszalski, B; Moffat, A F J; Parker, Q A; Udalski, A

    2009-01-01

    Binarity has been hypothesised to play an important, if not ubiquitous, role in the formation of planetary nebulae (PNe). Yet there remains a severe paucity of known binary central stars required to test the binary hypothesis and to place strong constraints on the physics of the common-envelope (CE) phase of binary stellar evolution. Large photometric surveys offer an unrivalled opportunity to efficiently discover many binary central stars. We have combined photometry from the OGLE microlensing survey with the largest sample of PNe towards the Galactic Bulge to systematically search for new binaries. A total of 21 periodic binaries were found thereby more than doubling the known sample. The orbital period distribution was found to be best described by CE population synthesis models when no correlation between primary and secondary masses is assumed for the initial mass ratio distribution. A comparison with post-CE white dwarf binaries indicates both distributions are representative of the true post-CE period ...

  19. Planet Scattering Around Binaries: Ejections, Not Collisions

    CERN Document Server

    Smullen, Rachel A; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Asid...

  20. Evolution of non-synchronized binary systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A model for binary evolution is introduced which can determine whether the rotation of components is synchronized with the orbital motion, and can calculate the evolution of both the synchronized and non-synchronized binary systems. With this model, the evolution of a binary system consisting of a 9 M⊙ star and a 6 M⊙ star is studied with mass transfer Case B. The result shows that the synchronization of the rotational and orbital periods can be reached when the binary system is a detached system and before the occurrence of the first mass transfer. After the onset of the first mass transfer, the binary system becomes non-synchronized. The mass accepted component (the secondary) rotates faster with a period much smaller than that of the orbital motion.

  1. Evolution of non-synchronized binary systems

    Institute of Scientific and Technical Information of China (English)

    黄润乾; 曾艺蓉

    2000-01-01

    A model for binary evolution is introduced which can determine whether the rotation of components is synchronized with the orbital motion, and can calculate the evolution of both the synchronized and non-synchronized binary systems. With this model, the evolution of a binary system consisting of a 9 M star and a 6 M star is studied with mass transfer Case B. The result shows that the synchronization of the rotational and orbital periods can be reached when the binary system is a detached system and before the occurrence of the first mass transfer. After the onset of the first mass transfer, the binary system becomes non-synchronized. The mass accepted component (the secondary) rotates faster with a period much smaller than that of the orbital motion.

  2. Terrestrial Planet Formation in Binary Star Systems

    Science.gov (United States)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  3. Development of an inter-atomic potential for the Pd-H binary system.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Jonathan A.; Hoyt, Jeffrey John (McMaster University, Hamilton, Ontario, Canada); Leonard, Francois Leonard; Griffin, Joshua D.; Zhou, Xiao Wang

    2007-09-01

    Ongoing research at Sandia National Laboratories has been in the area of developing models and simulation methods that can be used to uncover and illuminate the material defects created during He bubble growth in aging bulk metal tritides. Previous efforts have used molecular dynamics calculations to examine the physical mechanisms by which growing He bubbles in a Pd metal lattice create material defects. However, these efforts focused only on the growth of He bubbles in pure Pd and not on bubble growth in the material of interest, palladium tritide (PdT), or its non-radioactive isotope palladium hydride (PdH). The reason for this is that existing inter-atomic potentials do not adequately describe the thermodynamics of the Pd-H system, which includes a miscibility gap that leads to phase separation of the dilute (alpha) and concentrated (beta) alloys of H in Pd at room temperature. This document will report the results of research to either find or develop inter-atomic potentials for the Pd-H and Pd-T systems, including our efforts to use experimental data and density functional theory calculations to create an inter-atomic potential for this unique metal alloy system.

  4. Virtual gap dielectric wall accelerator

    Science.gov (United States)

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  5. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  6. Binary Cepheids from optical interferometry

    CERN Document Server

    Gallenne, A; Mérand, A; Monnier, J D; Pietrzyński, J Breitfelder G; Gieren, W

    2013-01-01

    Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (1-40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.

  7. Record-Breaking Eclipsing Binary

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two eclipses are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two eclipses. (The blue KELT observations during the eclipse show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the eclipse last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind

  8. Folk Belief Theory, the Rigor Gap, and the Achievement Gap

    Science.gov (United States)

    Torff, Bruce

    2014-01-01

    Folk belief theory is suggested as a primary cause for the persistence of the achievement gap. In this research-supported theory, culturally specified folk beliefs about learning and teaching prompt educators to direct more rigorous curriculum to high-advantage students but not to low-advantage students, resulting in impoverished pedagogy in…

  9. Research on carbon dioxide miscible flooding by Technology Research Center of Japan National Oil Corporation. Current status of CO/sub 2/ flooding field application, Work honored with the 31st JAPT award

    Energy Technology Data Exchange (ETDEWEB)

    Tanakadate, Tadao

    1988-03-01

    The application examples in world on carbon dioxide miscible flooding which is an enhanced oil recovery method and the outline of field pilot test in Japan which will start from fiscal 1989 were reported. In the USA, there are fifty three examples on carbon dioxide miscible flooding and thirty one examples on carbon dioxide immiscible flooding. The enhanced rates of oil recovery by carbon dioxide miscible flooding are 7 to 13 %. In Hungary, the oil reservior pressures were increased rapidly due to the carbon dioxide injection and the push by water, and the recovery rates of 24 % and more were achieved. In Turkey, carbon dioxide immiscible flooding is in a trial stage. In these countries, carbon dioxide can be provided comparatively easily owing to the existences of the carbon dioxide fields, and the advantageous conditions are utilized. In Japan, the pilot tests are carried out with main research subjects on the phase behavior of carbon dioxide-oil system, prospect for performance of carbon dioxide miscible flooding by oil reservior simulation. (10 figs, 2 tabs, 5 refs)

  10. The Emissions Gap Report 2014

    DEFF Research Database (Denmark)

    Farrell, Timothy Clifford

    This fifth Emissions Gap report has a different focus from previous years. While it updates the 2020 emissions gap analysis, it gives particular attention to the implications of the global carbon dioxide emissions budget for staying within the 2 °C limit beyond 2020. It does so because countries...... are giving increasing attention to where they need to be in 2025, 2030 and beyond. Furthermore, this year’s update of the report benefits from the findings on the emissions budget from the latest series of Intergovernmental Panel on Climate Change (IPCC) reports...

  11. Microstrip microwave band gap structures

    Indian Academy of Sciences (India)

    V Subramanian

    2008-04-01

    Microwave band gap structures exhibit certain stop band characteristics based on the periodicity, impedance contrast and effective refractive index contrast. These structures though formed in one-, two- and three-dimensional periodicity, are huge in size. In this paper, microstrip-based microwave band gap structures are formed by removing the substrate material in a periodic manner. This paper also demonstrates that these structures can serve as a non-destructive characterization tool for materials, a duplexor and frequency selective coupler. The paper presents both experimental results and theoretical simulation based on a commercially available finite element methodology for comparison.

  12. Stability of multiplanet systems in binaries

    Science.gov (United States)

    Marzari, F.; Gallina, G.

    2016-10-01

    Context. When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman & Wiegert (1999, AJ, 117, 621) within which planets are stable against the binary perturbations, and the Hill stability limit Δ determining the minimum separation beyond which two planets will avoid mutual close encounters. Both these parameters are derived in different contexts, i.e. Δ is usually adopted for computing the stability limit of two planets around a single star while ac is computed for a single planet in a binary system. Aims: Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. Methods: We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. Results: First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability and it does not account for planets trapped in resonance with the companion star well beyond ac. For two-planet systems, the value of Δ is close to that computed for planets around single stars, but the level of chaoticity close to it substantially increases for smaller semimajor axes and higher eccentricities of the binary orbit. In these configurations ac also begins to be unreliable and non-linear secular resonances with the stellar companion lead to chaotic behaviour well within ac, even for single planet systems. For two planet systems, the superposition of mean motion resonances, either mutual or with the binary companion, and non-linear secular resonances may lead to chaotic behaviour in all cases. We have developed a parametric semi-empirical formula determining the minimum value of the binary semimajor axis, for a given

  13. The Adaptation Gap Report - a Preliminary Assessment

    DEFF Research Database (Denmark)

    Alverson, Keith; Olhoff, Anne; Noble, Ian;

    This first Adaptation Gap report provides an equally sobering assessment of the gap between adaptation needs and reality, based on preliminary thinking on how baselines, future goals or targets, and gaps between them might be defined for climate change adaptation. The report focuses on gaps in de...... in developing countries in three important areas: finance, technology and knowledge....

  14. Limiting eccentricity of sub-parsec massive black hole binaries surrounded by self-gravitating gas discs

    CERN Document Server

    Rödig, Constanze; Sesana, Alberto; Cuadra, Jorge; Colpi, Monica

    2011-01-01

    We study the dynamics of supermassive black hole binaries embedded in circumbinary gaseous discs, with the SPH code Gadget-2. The sub-parsec binary (of total mass M and mass ratio q=1/3) has excavated a gap and transfers its angular momentum to the self--gravitating disc (M_disc=0.2 M). We explore the changes of the binary eccentricity e, by simulating a sequence of binary models that differ in the initial eccentricity e_0, only. In initially low-eccentric binaries, the eccentricity increases with time, while in high-eccentric binaries e declines, indicating the existence of a limiting eccentricity e_crit that is found to fall in the interval [0.6,0.8]. We also present an analytical interpretation for this saturation limit. An important consequence of the existence of e_crit is the detectability of a significant residual eccentricity e_LISA} by the proposed gravitational wave detector LISA. It is found that at the moment of entering the LISA frequency domain e_LISA ~ 10^{-3}-10^{-2}; a signature of its earlie...

  15. How Many CVs are Crossing the Period Gap? A Test for the Disruption of Magnetic Braking

    CERN Document Server

    Davis, P J; Willems, B; Gänsicke, B T

    2008-01-01

    We apply population synthesis techniques to calculate the present day number of two types of white dwarf-main sequence star (WDMS) binaries within the cataclysmic variable period gap. The first are post-common envelope binaries with secondary stars that have masses between 0.17 and 0.36 Msun (gPCEBs), such that they will commence mass transfer within the period gap. The second type are systems that were CVs at some point in their past, but detached once they evolved down in orbital period to ~3 h as a consequence of disrupted magnetic braking, and are crossing the period gap via gravitational radiation (dCVs). Full population synthesis calculations are performed where we assume either constant, global values of the common envelope ejection efficiency, or consider the ejection efficiency as a function of secondary mass. Several forms of magnetic braking are also considered. We predict an excess of dCVs over gPCEBs within the period gap of ~4 to ~13 assuming an ejection efficiency between 0.1 and 0.6, and a fla...

  16. Binary dynamics near a massive black hole

    CERN Document Server

    Hopman, Clovis

    2009-01-01

    We analyze the dynamical evolution of binary stars that interact with a static background of single stars in the environment of a massive black hole (MBH). All stars are considered to be single mass, Newtonian point particles. We follow the evolution of the energy E and angular momentum J of the center of mass of the binaries with respect to the MBH, as well as their internal semi-major axis a, using a Monte Carlo method. For a system like the Galactic center, the main conclusions are the following: (1) The binary fraction can be of the order of a few percent outside 0.1 pc, but decreases quickly closer to the MBH. (2) Within ~0.1 pc, binaries can only exist on eccentric orbits with apocenters much further away from the MBH. (3) Far away from the MBH, loss-cone effects are the dominant mechanism that disrupts binaries with internal velocities close to the velocity dispersion. Closer to the MBH, three-body encounters are more effective in disrupting binaries. (4) The rate at which hard binaries become tighter ...

  17. Interrupted Binary Mass Transfer in Star Clusters

    CERN Document Server

    Leigh, Nathan W C; Toonen, Silvia

    2016-01-01

    Binary mass transfer is at the forefront of some of the most exciting puzzles of modern astrophysics, including Type Ia supernovae, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this time-scale to the mean time for stable mass transfer to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing mass transfer that are expected to be disrupted as a function of the host cluster pro...

  18. The origin of very wide binary stars

    CERN Document Server

    Kouwenhoven, M B N; Davies, Melvyn B; Parker, Richard J; Kroupa, P; Malmberg, D

    2011-01-01

    A large population of fragile, wide (> 1000 AU) binary systems exists in the Galactic field and halo. These wide binary stars cannot be primordial because of the high stellar density in star forming regions, while formation by capture in the Galactic field is highly improbable. We propose that these binary systems were formed during the dissolution phase of star clusters (see Kouwenhoven et al. 2010, for details). Stars escaping from a dissolving star cluster can have very similar velocities, which can lead to the formation of a wide binary systems. We carry out N-body simulations to test this hypothesis. The results indicate that this mechanism explains the origin of wide binary systems in the Galaxy. The resulting wide binary fraction and semi-major axis distribution depend on the initial conditions of the dissolving star cluster, while the distributions in eccentricity and mass ratio are universal. Finally, since most stars are formed in (relatively tight) primordial binaries, we predict that a large fract...

  19. Operation of Narrow Gap RPC with Tetrafluoroethane Based Mixture.

    CERN Document Server

    Ammosov, V; Koreshev, V; Sviridov, Yu; Zaetz, V G; Semak, A

    1999-01-01

    Charge, fired strip multiplicity and arrival time distributions for the induced signal were investigated for the $2 ~mm$ gap RPC operating with several tetrafluoroethane ($C_{2}H_{2}F_{4}$) based mixtures with variation of isobutane ($iC_{4}H_{10}$) and sulphur hexafluoride ($SF_{6}$) concentrations. Suppression of the large fast charges for the mixtures containing $SF_{6}$ in comparison with the binary $C_{2}H_{2}F_{4}$/$iC_{4}H_{10}$ mixture was confirmed. This suppression allows to have a wide plateau region ($ge1~kV$) with small average charge and reduced tail of high charges. Exclusion of isobutane from the mixture with $2%$ of $SF_{6}$ does not change charge distributions.

  20. Searching for spectroscopic binaries within transition disk objects

    CERN Document Server

    Kohn, Saul A; Weinberger, Alycia J; Carlberg, Joleen K; Llama, Joe

    2016-01-01

    Transition disks (TDs) are intermediate stage circumstellar disks characterized by an inner gap within the disk structure. To test whether these gaps may have been formed by closely orbiting, previously undetected stellar companions, we collected high-resolution optical spectra of 31 TD objects to search for spectroscopic binaries (SBs). Twenty-four of these objects are in Ophiuchus and seven are within the Coronet, Corona Australis, and Chameleon I star-forming regions. We measured radial velocities for multiple epochs, obtaining a median precision of 400 ms$^{-1}$. We identified double-lined SB SSTc2d J163154.7-250324 in Ophiuchus, which we determined to be composed of a K7($\\pm$0.5) and a K9($\\pm$0.5) star, with orbital limits of $a<$0.6 AU and $P<$150 days. This results in an SB fraction of 0.04$^{+0.12}_{-0.03}$ in Ophiuchus, which is consistent with other spectroscopic surveys of non-TD objects in the region. This similarity suggests that TDs are not preferentially sculpted by the presence of clos...

  1. Burkholderia pseudomallei Data Gap Analysis

    Science.gov (United States)

    2015-11-01

    conducting this review is to identify the major biodefense relevant data gaps critical to better understanding B. pseudomallei infections and how they are...of patients (Table 2-1). Much of the data has excellent demographic and clinical resolution including age, sex, symptoms, duration of illness, risk...inhalation and enteral. Presentations include pneumonia , genitourinary, cutaneous, general bacteremia, septic arthritis and neurological

  2. The "Efficacy-Effectiveness Gap"

    DEFF Research Database (Denmark)

    Nordon, Clementine; Karcher, Helene; Groenwold, Rolf H H;

    2016-01-01

    BACKGROUND: The concept of the "efficacy-effectiveness gap" (EEG) has started to challenge confidence in decisions made for drugs when based on randomized controlled trials alone. Launched by the Innovative Medicines Initiative, the GetReal project aims to improve understanding of how to reconcil...

  3. Income Gap Widens in Beijing

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The income gap between the highest-and lowestincome groups in Beijing, China's capital city, grew to 4:1 in 2004, up from 3:1 in 2003, according to a sampling survey of 2,000 urban households conducted by the Beijing Municipal Statistics Bureau.Among the most important factors affecting income levels were education and profession, the survey indicated.

  4. Gap Analysis Bulletin No. 13

    Science.gov (United States)

    2005-12-01

    Project Laurence L. Strong of the spatial distribution of the accuracy parameters by applying U.S. Geological Survey, Northern Prairie Wildlife...Wildlife Resources year: at the University of Idaho. Her dissertation focuses on the " GIS Analyst Ree Brannon has returned to school at the population...54 North Dakota Gap Analysis Project Laurence L. Strong

  5. A PHOTONIC BAND GAP FIBRE

    DEFF Research Database (Denmark)

    1999-01-01

    An optical fibre having a periodicidal cladding structure provididing a photonic band gap structure with superior qualities. The periodical structure being one wherein high index areas are defined and wherein these are separated using a number of methods. One such method is the introduction...

  6. Interrupted Binary Mass Transfer in Star Clusters

    Science.gov (United States)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  7. A transition in circumbinary accretion discs at a binary mass ratio of 1:25

    Science.gov (United States)

    D'Orazio, Daniel J.; Haiman, Zoltán; Duffell, Paul; MacFadyen, Andrew; Farris, Brian

    2016-07-01

    We study circumbinary accretion discs in the framework of the restricted three-body problem (R3Bp) and via numerically solving the height-integrated equations of viscous hydrodynamics. Varying the mass ratio of the binary, we find a pronounced change in the behaviour of the disc near mass ratio q ≡ Ms/Mp ˜ 0.04. For mass ratios above q = 0.04, solutions for the hydrodynamic flow transition from steady, to strongly fluctuating; a narrow annular gap in the surface density around the secondary's orbit changes to a hollow central cavity; and a spatial symmetry is lost, resulting in a lopsided disc. This phase transition is coincident with the mass ratio above which stable orbits do not exist around the L4 and L5 equilibrium points of the R3Bp. Using the DISCO code, we find that for thin discs, for which a gap or cavity can remain open, the mass ratio of the transition is relatively insensitive to disc viscosity and pressure. The q = 0.04 transition has relevance for the evolution of massive black hole binary+disc systems at the centres of galactic nuclei, as well as for young stellar binaries and possibly planets around brown dwarfs.

  8. Development and verification of simplified prediction models for enhanced oil recovery applications. CO/sub 2/ (miscible flood) predictive model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Paul, G.W.

    1984-10-01

    A screening model for CO/sub 2/ miscible flooding has been developed consisting of a reservoir model for oil rate and recovery and an economic model. The reservoir model includes the effects of viscous fingering, reservoir heterogeneity, gravity segregation and areal sweep. The economic model includes methods to calculate various profitability indices, the windfall profits tax, and provides for CO/sub 2/ recycle. The model is applicable to secondary or tertiary floods, and to solvent slug or WAG processes. The model does not require detailed oil-CO/sub 2/ PVT data for execution, and is limited to five-spot patterns. A pattern schedule may be specified to allow economic calculations for an entire project to be made. Models of similar architecture have been developed for steam drive, in-situ combustion, surfactant-polymer flooding, polymer flooding and waterflooding. 36 references, 41 figures, 4 tables.

  9. Strong substrate-stabilizing effect of a water-miscible ionic liquid [BMIM][BF(4)] in the catalysis of horseradish peroxidase.

    Science.gov (United States)

    Hong, Eun Sik; Kwon, O Yul; Ryu, Keungarp

    2008-03-01

    The effects of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]), on both thermodynamics and kinetic mechanism of the horseradish peroxidase (HRP)-catalyzed oxidation of guaiacol (2-methoxyphenol) by H(2)O(2) were investigated. The ionic liquid stabilized the ground state of guaiacol by causing an 8-fold increase of K(m) from 3 to 23 mM upon the addition of 25% (v/v) [BMIM][BF(4)]. In addition, the effect of [BMIM][BF(4)] in decreasing the k(cat) value of HRP catalysis was described by a non-competitive inhibition mechanism. The value of the inhibition constant of [BMIM][BF(4)] was 2.9 M indicating that the ionic liquid plays the role of a weak non-competitive inhibitor for HRP catalysis.

  10. Fast algorithms for generating binary holograms

    CERN Document Server

    Stuart, Dustin; Kuhn, Axel

    2014-01-01

    We describe three algorithms for generating binary-valued holograms. Our methods are optimised for producing large arrays of tightly focussed optical tweezers for trapping particles. Binary-valued holograms allow us to use a digital mirror device (DMD) as the display element, which is much faster than other alternatives. We describe how our binary amplitude holograms can be used to correct for phase errors caused by optical aberrations. Furthermore, we compare the speed and accuracy of the algorithms for both periodic and arbitrary arrangements of traps, which allows one to choose the ideal scheme depending on the circumstances.

  11. Discovery of a 2 Kpc Binary Quasar

    OpenAIRE

    Shields, G. A.; Junkkarinen, V.; Beaver, E. A.; Burbidge, E. M.; Cohen, R. D.; Hamann, F.; Lyons, R. W.

    2001-01-01

    LBQS 0103$-$2753 is a binary quasar with a separation of only 0.3 arcsec. The projected spacing of 2.3 kpc at the distance of the source (z = 0.848) is much smaller than that of any other known binary QSO. The binary nature is demonstrated by the very different spectra of the two components and the low probability of a chance pairing. LBQS 0103$-$2753 presumably is a galaxy merger with a small physical separation between the two supermassive black holes. Such objects may provide important con...

  12. Binary Cu-Zr Bulk Metallic Glasses

    Institute of Scientific and Technical Information of China (English)

    TANG Mei-Bo; ZHAO De-Qian; PAN Ming-Xiang; WANG Wei-Hua

    2004-01-01

    @@ We report that bulk metallic glasses (BMGs) can be produced up to 2 mm by a copper mould casting in Cux Zr1-x binary alloy with a wide glass forming composition range (45 < x < 60 at.%). We find that the formation mechanism for the binary Cu-Zr binary BMG-forming alloy is obviously different from that of the intensively studied multicomponent BMGs. Our results demonstrate that the criteria for the multicomponent alloys with composition near deep eutectic and strong liquid behaviour are no longer the major concern for designing BMGs.

  13. Blind iterative deconvolution of binary star images

    CERN Document Server

    Saha, S K

    1997-01-01

    The technique of Blind Iterative De-convolution (BID) was used to remove the atmospherically induced point spread function (PSF) from short exposure images of two binary stars, HR 5138 and HR 5747 obtained at the cassegrain focus of the 2.34 meter Vainu Bappu Telescope(VBT), situated at Vainu Bappu Observatory (VBO), Kavalur. The position angles and separations of the binary components were seen to be consistent with results of the auto-correlation technique, while the Fourier phases of the reconstructed images were consistent with published observations of the binary orbits.

  14. Division Unit for Binary Integer Decimals

    DEFF Research Database (Denmark)

    Lang, Tomas; Nannarelli, Alberto

    2009-01-01

    -recurrence algorithm to BID representation and implement the division unit in standard cell technology. The implementation of the proposed BID division unit is compared to that of a BCD based unit implementing the same algorithm. The comparison shows that for normalized operands the BID unit has the same latency......In this work, we present a radix-10 division unit that is based on the digit-recurrence algorithm and implements binary encodings (binary integer decimal or BID) for significands. Recent decimal division designs are all based on the binary coded decimal (BCD) encoding. We adapt the radix-10 digit...

  15. The use of rheology to elucidate the granulation mechanisms of a miscible and immiscible system during continuous twin-screw melt granulation.

    Science.gov (United States)

    Monteyne, Tinne; Heeze, Liza; Mortier, Séverine Thérèse F C; Oldörp, Klaus; Nopens, Ingmar; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-08-20

    Twin-screw hot melt granulation (TS HMG) is a valuable, but still unexplored alternative to granulate temperature and moisture sensitive drugs in a continuous way. Recently, the material behavior of an immiscible drug-binder blend during TS HMG was unraveled by using a rheometer and differential scanning calorimetry (DSC). Additionally, vibrational spectroscopic techniques proved the link between TS HMG and rheology since equal interactions at molecular level did occur in both processes. This allowed to use a rheometer to gain knowledge of the material behavior during hot melt processing of an immiscible drug-binder blend. However, miscibility of a drug-binder formulation and drug-binder interactions appear to influence the rheological properties and, hence conceivably also the granulation mechanism. The aim of this research was to examine if the TS HMG process of a miscible formulation system is comparable with the mechanism of an immiscible system and to evaluate whether rheology still serves as a useful tool to understand and optimize the hot melt granulation (HMG) process. The executed research (thermal analysis, rheological parameters and spectroscopic data) demonstrated the occurrence of a high and broad tan(δ) curve without a loss peak during the rheological temperature ramp which implies a higher material deformability without movement of the softened single polymer chains. Spectroscopic analysis revealed drug-polymer interactions which constrain the polymer to flow independently. As a result, the binder distribution step, which generally follows the immersion step, was hindered. This insight assisted the understanding of the granule properties. Inhomogeneous granules were produced due to large initial nuclei or adhesion of multiple smaller nuclei. Consequently, a higher granulation temperature was required in order to get the binder more homogeneously distributed within the granules.

  16. Multiple-relaxation-time lattice Boltzmann model for incompressible miscible flow with large viscosity ratio and high Péclet number

    Science.gov (United States)

    Meng, Xuhui; Guo, Zhaoli

    2015-10-01

    A lattice Boltzmann model with a multiple-relaxation-time (MRT) collision operator is proposed for incompressible miscible flow with a large viscosity ratio as well as a high Péclet number in this paper. The equilibria in the present model are motivated by the lattice kinetic scheme previously developed by Inamuro et al. [Philos. Trans. R. Soc. London, Ser. A 360, 477 (2002), 10.1098/rsta.2001.0942]. The fluid viscosity and diffusion coefficient depend on both the corresponding relaxation times and additional adjustable parameters in this model. As a result, the corresponding relaxation times can be adjusted in proper ranges to enhance the performance of the model. Numerical validations of the Poiseuille flow and a diffusion-reaction problem demonstrate that the proposed model has second-order accuracy in space. Thereafter, the model is used to simulate flow through a porous medium, and the results show that the proposed model has the advantage to obtain a viscosity-independent permeability, which makes it a robust method for simulating flow in porous media. Finally, a set of simulations are conducted on the viscous miscible displacement between two parallel plates. The results reveal that the present model can be used to simulate, to a high level of accuracy, flows with large viscosity ratios and/or high Péclet numbers. Moreover, the present model is shown to provide superior stability in the limit of high kinematic viscosity. In summary, the numerical results indicate that the present lattice Boltzmann model is an ideal numerical tool for simulating flow with a large viscosity ratio and/or a high Péclet number.

  17. IMPACTS OF THE NUMERICAL DISPERSION ON CO2 MISCIBLE FLOODING%数值弥散对CO2混相驱的影响

    Institute of Scientific and Technical Information of China (English)

    汪勇; 汤勇; 王长权; 徐建; 姚陆峰

    2013-01-01

    数值弥散效应影响油藏数值模拟结果的精度.基于实际油藏流体和CO2-原油体系室内实验,建立一维均质模型,研究数值弥散对CO2多级接触混相驱替过程的影响,比较数值弥散与物理弥散对CO2混相驱替的影响.结果表明,数值弥散会影响驱替过程中相间传质,数值弥散越大,CO2会越早突破,导致采收率越低,驱替前缘变得模糊化.数值弥散与物理弥散作用相似,具有相同的数量级,二者存在细微的差别.%Numerical dispersion effect will influence the accuracy of oil reservoir numerical simulation. Based on the actual reservoir fluids and the indoor experiment of CO2-oil system, the 1D homogeneous model is set up to study the influence of the numerical dispersion on the process of CO2 multiple-contact miscible flooding and compare the influences of the numerical and physical dispersions on CO2 miscible flooding. The numerical dispersion will affect the mass transfer between CO2 and oil. The results show that the former dispersion can impact the inter-phase mass transfer in the above process, the more serious the numerical dispersion is, the earlier the CO2 breakthrough will be, and finally the lower the recovery will be, and the displacing front will become smeared. Physical and numerical dispersions have similar impacts and the same magnitude, but there are subtle differences between them.

  18. Preparation of carbamazepine-Soluplus solid dispersions by hot-melt extrusion, and prediction of drug-polymer miscibility by thermodynamic model fitting.

    Science.gov (United States)

    Djuris, Jelena; Nikolakakis, Ioannis; Ibric, Svetlana; Djuric, Zorica; Kachrimanis, Kyriakos

    2013-05-01

    Hot-melt extrusion (HME) is a dust- and solvent-free continuous process enabling the preparation of a variety of solid dosage forms containing solid dispersions of poorly soluble drugs into thermoplastic polymers. Miscibility of drug and polymer is a prerequisite for stable solid dispersion formation. The present study investigates the feasibility of forming solid dispersions of carbamazepine (CBZ) into polyethyleneglycol-polyvinyl caprolactam-polyvinyl acetate grafted copolymer (Soluplus) by hot-melt extrusion. Physicochemical properties of the raw materials, extrudates, co-melted products, and corresponding physical mixtures were characterized by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance infrared (ATR-FTIR) spectroscopy and hot stage microscopy (HSM), while miscibility of CBZ and Soluplus was estimated on the basis of the Flory-Huggins theory, Hansen solubility parameters, and solid-liquid equilibrium equation. It was found that hot-melt extrusion of carbamazepine and Soluplus is feasible on a single-screw hot-melt extruder without the addition of plasticizers. DSC analysis and FTIR spectroscopy revealed that a molecular dispersion is formed when the content of CBZ does not exceed ∼5% w/w while higher CBZ content results in a microcrystalline dispersion of CBZ form III crystals, with the molecularly dispersed percentage increasing with extrusion temperature, at the risk of inducing transformation to the undesirable form I of CBZ. Thermodynamic modeling elucidated potential limitations and temperature dependence of solubility/dispersibility of carbamazepine in Soluplus hot-melt extrudates. The results obtained by thermodynamic models are in agreement with the findings of the HME processing, encouraging therefore their further application in the HME process development.

  19. Wavelet-based method for computing elastic band gaps of one-dimensional phononic crystals

    Institute of Scientific and Technical Information of China (English)

    YAN; ZhiZhong; WANG; YueSheng

    2007-01-01

    A wavelet-based method was developed to compute elastic band gaps of one-dimensional phononic crystals. The wave field was expanded in the wavelet basis and an equivalent eigenvalue problem was derived in a matrix form involving the adaptive computation of integrals of the wavelets. The method was then applied to a binary system. For comparison, the elastic band gaps of the same one-di- mensional phononic crystals computed with the wavelet method and the well- known plane wave expansion (PWE) method are both presented in this paper. The numerical results of the two methods are in good agreement while the computation costs of the wavelet method are much lower than that of PWE method. In addition, the adaptability of wavelets makes the method possible for efficient band gap computation of more complex phononic structures.

  20. Busting Up Binaries: Encounters Between Compact Binaries and a Supermassive Black Hole

    CERN Document Server

    Addison, Eric; Larson, Shane

    2015-01-01

    Given the stellar density near the galactic center, close encounters between compact object binaries and the supermassive black hole are a plausible occurrence. We present results from a numerical study of close to 13 million such encounters. Consistent with previous studies, we corroborate that, for binary systems tidally disrupted by the black hole, the component of the binary remaining bound to the hole has eccentricity ~ 0.97 and circularizes dramatically by the time it enters the classical LISA band. Our results also show that the population of surviving binaries merits attention. These binary systems experience perturbations to their internal orbital parameters with potentially interesting observational consequences. We investigated the regions of parameter space for survival and estimated the distribution of orbital parameters post-encounter. We found that surviving binaries harden and their eccentricity increases, thus accelerating their merger due gravitational radiation emission and increasing the p...

  1. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  2. Binary neutron star merger simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bruegmann, Bernd [Jena Univ. (Germany)

    2016-11-01

    Our research focuses on the numerical tools necessary to solve Einstein's equations. In recent years we have been particularly interested in spacetimes consisting of two neutron stars in the final stages of their evolution. Because of the emission of gravitational radiation, the objects are driven together to merge; the emitted gravitational wave signal is visualized. This emitted gravitational radiation carries energy and momentum away from the system and contains information about the system. Late last year the Laser Interferometer Gravitational-wave Observatory (LIGO) began searches for these gravitational wave signals at a sensitivity at which detections are expected. Although such systems can radiate a significant amount of their total mass-energy in gravitational waves, the gravitational wave signals one expects to receive on Earth are not strong, since sources of gravitational waves are often many millions of light years away. Therefore one needs accurate templates for the radiation one expects from such systems in order to be able to extract them out of the detector's noise. Although analytical models exist for compact binary systems when the constituents are well separated, we need numerical simulation to investigate the last orbits before merger to obtain accurate templates and validate analytical approximations. Due to the strong nonlinearity of the equations and the large separation of length scales, these simulations are computationally demanding and need to be run on large supercomputers. When matter is present the computational cost as compared to pure black hole (vacuum) simulations increases even more due to the additional matter fields. But also more interesting astrophysical phenomena can happen. In fact, there is the possibility for a strong electromagnetic signal from the merger (e.g., a short gamma-ray burst or lower-energy electromagnetic signatures from the ejecta) and significant neutrino emission. Additionally, we can expect that

  3. Phylogenetic inference under varying proportions of indel-induced alignment gaps

    Directory of Open Access Journals (Sweden)

    Gadagkar Sudhindra R

    2009-08-01

    Full Text Available Abstract Background The effect of alignment gaps on phylogenetic accuracy has been the subject of numerous studies. In this study, we investigated the relationship between the total number of gapped sites and phylogenetic accuracy, when the gaps were introduced (by means of computer simulation to reflect indel (insertion/deletion events during the evolution of DNA sequences. The resulting (true alignments were subjected to commonly used gap treatment and phylogenetic inference methods. Results (1 In general, there was a strong – almost deterministic – relationship between the amount of gap in the data and the level of phylogenetic accuracy when the alignments were very "gappy", (2 gaps resulting from deletions (as opposed to insertions contributed more to the inaccuracy of phylogenetic inference, (3 the probabilistic methods (Bayesian, PhyML & "MLε, " a method implemented in DNAML in PHYLIP performed better at most levels of gap percentage when compared to parsimony (MP and distance (NJ methods, with Bayesian analysis being clearly the best, (4 methods that treat gapped sites as missing data yielded less accurate trees when compared to those that attribute phylogenetic signal to the gapped sites (by coding them as binary character data – presence/absence, or as in the MLε method, and (5 in general, the accuracy of phylogenetic inference depended upon the amount of available data when the gaps resulted from mainly deletion events, and the amount of missing data when insertion events were equally likely to have caused the alignment gaps. Conclusion When gaps in an alignment are a consequence of indel events in the evolution of the sequences, the accuracy of phylogenetic analysis is likely to improve if: (1 alignment gaps are categorized as arising from insertion events or deletion events and then treated separately in the analysis, (2 the evolutionary signal provided by indels is harnessed in the phylogenetic analysis, and (3 methods that

  4. New Insights into X-ray Binaries

    CERN Document Server

    Casares, Jorge

    2009-01-01

    X-ray binaries are excellent laboratories to study collapsed objects. On the one hand, transient X-ray binaries contain the best examples of stellar-mass black holes while persistent X-ray binaries mostly harbour accreting neutron stars. The determination of stellar masses in persistent X-ray binaries is usually hampered by the overwhelming luminosity of the X-ray heated accretion disc. However, the discovery of high-excitation emission lines from the irradiated companion star has opened new routes in the study of compact objects. This paper presents novel techniques which exploits these irradiated lines and summarises the dynamical masses obtained for the two populations of collapsed stars: neutron stars and black holes.

  5. A mesoscopic model for binary fluids

    CERN Document Server

    Echeverria, C; Alvarez-Llamoza, O; Orozco-Guillén, E E; Morales, M; Cosenza, M G

    2016-01-01

    We propose a model to study symmetric binary fluids, based in the mesoscopic molecular simulation technique known as multiparticle collision, where space and state variables are continuous while time is discrete. We include a repulsion rule to simulate segregation processes that does not require the calculation of the interaction forces between particles, thus allowing the description of binary fluids at a mesoscopic scale. The model is conceptually simple, computationally efficient, maintains Galilean invariance, and conserves the mass and the energy in the system at micro and macro scales; while momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as density profile, width of the interface, phase separation and phase growth. We also apply the model to study binary fluids in crowded environments with consistent results.

  6. Red-giant stars in eccentric binaries

    Directory of Open Access Journals (Sweden)

    Beck P. G.

    2015-01-01

    Full Text Available The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs.

  7. Binary Biometric Representation through Pairwise Polar Quantization

    NARCIS (Netherlands)

    Chen, Chun; Veldhuis, Raymond; Tistarelli, M.; Nixon, M.

    2009-01-01

    Binary biometric representations have great significance for data compression and template protection. In this paper, we introduce pairwise polar quantization. Furthermore, aiming to optimize the discrimination between the genuine Hamming distance (GHD) and the imposter Hamming distance (IHD), we pr

  8. Searching for Pulsars in Close Binary Systems

    CERN Document Server

    Jouteux, S; Stappers, B W; Jonker, P; Van der Klis, M

    2001-01-01

    We present a detailed mathematical analysis of the Fourier response of binary pulsar signals whose frequencies are modulated by circular orbital motion. The fluctuation power spectrum of such signals is found to be \

  9. Tidal capture formation of Low Mass X-Ray Binaries from wide binaries in the field

    CERN Document Server

    Michaely, Erez

    2015-01-01

    We present a potentially efficient dynamical formation scenario for Low Mass X-ray Binaries (LMXBs) in the field, focusing on black-hole (BH) LMXBs. In this formation channel LMXBs are formed from wide binaries $(>1000$ AU) with a BH component and a stellar companion. The wide binary is perturbed by fly-by's of field stars and its orbit random-walks and changes over time. This diffusion process can drive the binary into a sufficiently eccentric orbit such that the binary components tidally interact at peri-center and the binary evolves to become a short period binary, which eventually evolves into an LMXB. The formation rate of LMXBs through this channel mostly depends on the number of such BH wide binaries progenitors, which in turn depends on the velocity kicks imparted to BHs (or NSs) at birth. We consider several models for the formation and survival of such wide binaries, and calculate the LMXB formation rates for each model. We find that models where BHs form through direct collapse with no/little natal...

  10. Evolution of Binary Stars in Multiple-Population Globular Clusters - II. Compact Binaries

    CERN Document Server

    Hong, Jongsuk; Sollima, Antonio; McMillan, Stephen L W; D'Antona, Franca; D'Ercole, Annibale

    2016-01-01

    We present the results of a survey of N-body simulations aimed at exploring the evolution of compact binaries in multiple-population globular clusters.We show that as a consequence of the initial differences in the structural properties of the first-generation (FG) and the second-generation (SG) populations and the effects of dynamical processes on binary stars, the SG binary fraction decreases more rapidly than that of the FG population. The difference between the FG and SG binary fraction is qualitatively similar to but quantitatively smaller than that found for wider binaries in our previous investigations.The evolution of the radial variation of the binary fraction is driven by the interplay between binary segregation, ionization and ejection. Ionization and ejection counteract in part the effects of mass segregation but for compact binaries the effects of segregation dominate and the inner binary fraction increases during the cluster evolution. We explore the variation of the difference between the FG an...

  11. Dixie Valley Bottoming Binary Unit

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Dale [Terra-Gen Sierra Holdings, LLC, Reno, NV (United States)

    2014-12-21

    This binary plant is the first air cooled, high-output refrigeration based waste heat recovery cycle in the industry. Its working fluid is environmentally friendly and as such, the permits that would be required with a hydrocarbon based cycle are not necessary. The unit is largely modularized, meaning that the unit’s individual skids were assembled in another location and were shipped via truck to the plant site. The Air Cooled Condensers (ACC), equipment piping, and Balance of Plant (BOP) piping were constructed at site. This project further demonstrates the technical feasibility of using low temperature brine for geothermal power utilization. The development of the unit led to the realization of low temperature, high output, and environmentally friendly heat recovery systems through domestic research and engineering. The project generates additional renewable energy, resulting in cleaner air and reduced carbon dioxide emissions. Royalty and tax payments to governmental agencies will increase, resulting in reduced financial pressure on local entities. The major components of the unit were sourced from American companies, resulting in increased economic activity throughout the country.

  12. Binary module test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, J.R.; Colley, T.C.; Pundyk, J.

    1980-12-01

    The objective of this project was to design and test a binary loop module representative of and scaleable to commercial size units. The design was based on state-of-the-art heat exchanger technology, and the purpose of the tests was to confirm performance of a supercritical boiling cycle using isobutane and a mixture of isobutane and isopentane as the secondary working fluid. The module was designed as one percent of a 50 MW unit. It was installed at Magma Power's East Mesa geothermal field and tested over a period of approximately 4 months. Most of the test runs were with isobutane but some data were collected for hydrocarbon mixtures. The results of the field tests are reported. In general these results indicate reasonably good heat balances and agreement with overall heat transfer coefficients calculated by current stream analysis methods and available fluid property data; however, measured pressure drops across the heat exchangers were 20 percent higher than estimated. System operation was stable under all conditions tested.

  13. Near-Optimal Compressive Binary Search

    OpenAIRE

    Malloy, Matthew L.; Nowak, Robert D.

    2012-01-01

    We propose a simple modification to the recently proposed compressive binary search. The modification removes an unnecessary and suboptimal factor of log log n from the SNR requirement, making the procedure optimal (up to a small constant). Simulations show that the new procedure performs significantly better in practice as well. We also contrast this problem with the more well known problem of noisy binary search.

  14. Statistical pattern classification with binary variables.

    Science.gov (United States)

    Young, T Y; Liu, P S; Rondon, R J

    1981-02-01

    Binary random variables are regarded as random vectors in a binary-field (modulo-2) linear vector space. A characteristic function is defined and related results derived using this formulation. Minimax estimation of probability distributions using an entropy criterion is investigated, which leads to an A-distribution and bilinear discriminant functions. Nonparametric classification approaches using Hamming distances and their asymptotic properties are discussed. Experimental results are presented.

  15. Binary compact object inspiral: Detection expectations

    Indian Academy of Sciences (India)

    Vassiliki Kalogera

    2004-10-01

    We review the current estimates of binary compact object inspiral rates in particular in view of the recently discovered highly relativistic binary pulsar J0737-3039. One of the robust results is that, because of this discovery, the rate estimates for binary neutron stars have increased by a factor of 6-7 independent of any uncertainties related to the pulsar population properties. This rate increase has dramatic implications for gravitational wave detectors. For initial LIGO, the most probable detection rates for double neutron star (DNS) inspirals is 1 event/(5{250) yr; at 95% confidence we obtain rates up to 1/1.5 yr. For advanced LIGO, the most probable rates are 20-1000 events/yr. These predictions, for the first time, bring the expectations for DNS detections by initial LIGO to the astrophysically relevant regime. We also use our models to predict that the large-scale Parkes multibeam pulsar survey with acceleration searches could detect an average of three to four binary pulsars similar to those known at present. In comparison, rate estimates for binaries with black holes are derived based on binary evolution calculation, and based on the optimistic ends of the ranges, remain an important candidate for inspiral detection in the next few years. We also consider another aspect of the detectability of binary inspiral: the effect of precession on the detection efficiency of astrophysically relevant binaries. Based on our current astrophysical expectations, large tilt angles are not favored. As a result the decrease in detection rate varies rather slowly with black hole spin magnitude and is within 20-30% of the maximum possible values.

  16. The DEBCat detached eclipsing binary catalogue

    OpenAIRE

    2014-01-01

    Detached eclipsing binary star systems are our primary source of measured physical properties of normal stars. I introduce DEBCat: a catalogue of detached eclipsing binaries with mass and radius measurements to the 2% precision necessary to put useful constraints on theoretical models of stellar evolution. The catalogue was begun in 2006, as an update of the compilation by Andersen (1991). It now contains over 170 systems, and new results are added on appearance in the refereed literature. DE...

  17. An improved catalog of halo wide binary candidates

    CERN Document Server

    Allen, Christine

    2014-01-01

    We present an improved catalog of halo wide binaries, compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. (2004), and Chanam\\'e \\& Gould. (2004) but we have also included binaries from the lists of Ryan (1992) and Zapatero-Osorio \\& Martin (2004). All binaries were carefully checked and their distances and systemic radial velocities are included, when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries we ended up with 211 probable halo binaries, for 150 of which radial velocities are available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law $f...

  18. Texture classification by texton: statistical versus binary.

    Directory of Open Access Journals (Sweden)

    Zhenhua Guo

    Full Text Available Using statistical textons for texture classification has shown great success recently. The maximal response 8 (Statistical_MR8, image patch (Statistical_Joint and locally invariant fractal (Statistical_Fractal are typical statistical texton algorithms and state-of-the-art texture classification methods. However, there are two limitations when using these methods. First, it needs a training stage to build a texton library, thus the recognition accuracy will be highly depended on the training samples; second, during feature extraction, local feature is assigned to a texton by searching for the nearest texton in the whole library, which is time consuming when the library size is big and the dimension of feature is high. To address the above two issues, in this paper, three binary texton counterpart methods were proposed, Binary_MR8, Binary_Joint, and Binary_Fractal. These methods do not require any training step but encode local feature into binary representation directly. The experimental results on the CUReT, UIUC and KTH-TIPS databases show that binary texton could get sound results with fast feature extraction, especially when the image size is not big and the quality of image is not poor.

  19. Spectroscopic subsystems in nearby wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5-m telescope to study short-period systems. Data reduction is described, mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, for some of them orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67pc. It is found that 43 binaries contain at least one subsystem and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods match the simple prescription proposed by the author (2014, AJ, 147, 87). The remaining 53 simple wide binaries with a median projected separation of 1300AU have the distri...

  20. Coronal activity from the ASAS eclipsing binaries

    CERN Document Server

    Szczygiel, D M; Paczynski, B; Pojmanski, G; Pilecki, B

    2008-01-01

    We combine the catalogue of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalogue, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L_X/L_bol ~ a few x 10^-4, similar to the ratio of soft X-ray to bolometric flux F_X/F_bol in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs -- stars with significant outer convection zones -- a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called "super-saturation" phenomena. Our work shows that wide-...

  1. Non-isothermal crystallization kinetics of partially miscible ethylene-vinyl acetate copolymer/low density polyethylene blends

    Directory of Open Access Journals (Sweden)

    2010-03-01

    Full Text Available The non-isothermal crystallization kinetics of ethylene-vinyl acetate copolymer (EVA, 14 wt% vinyl acetate content, low density polyethylene (LDPE and their binary blends with different blending ratio were investigated via differential scanning calorimetry. Jeziorny theory and Mo’s method were utilized in evaluating the crystallization behavior of both neat materials successfully. In the primary crystallization stage both EVA and LDPE had three-dimensional spherulitic growth mechanism. Apparently the crystallization rate of LDPE was faster than that of EVA at a low cooling rate. Increase in cooling rate limited the spherulites’ growth, which narrowed their rate difference. Influences from blending on the crystallization kinetics of each component in EVA/LDPE mixture were evaluated by Kissinger’s activation energy (∆E and Khanna’s crystallization rate coefficient (CRC. Inter-molecular interaction in the melt increased the ∆E of both EVA and LDPE components at the beginning of cooling. During the primary crystallization stage of LDPE, dilution effect from EVA facilitated the crystal growth in LDPE. Co-crystallization between EVA component and the secondary crystallization stage of LDPE component also increased the CRC of EVA. In blend of EVA/LDPE = 7/3, LDPE obtained the maximal CRC value of 174.2 h–1. Results obtained from various approaches accorded well with each other, which insured the rationality of conclusion.

  2. Filling in biodiversity threat gaps

    DEFF Research Database (Denmark)

    Joppa, L. N.; O'Connor, Brian; Visconti, Piero

    2016-01-01

    increase to 10,000 times the background rate should species threatened with extinction succumb to pressures they face (4). Reversing these trends is a focus of the Convention on Biological Diversity's 2020 Strategic Plan for Biodiversity and its 20 Aichi Targets and is explicitly incorporated...... into the United Nations' 2030 Agenda for Sustainable Development and its 17 Sustainable Development Goals (SDGs). We identify major gaps in data available for assessing global biodiversity threats and suggest mechanisms for closing them....

  3. Investigations of Pulsed Vacuum Gap.

    Science.gov (United States)

    1981-02-10

    re-az4,irc t:ata -.as taken .0thcut t1he cury-ent vino r’esistor. Initial data, with no current viewing resistor, were taken for a 35 mmn gap using an...Eastman, and J. Kivlin, "The Appearance of Micro- particles in Accelerator Tubes," Proc. of 8th Symp., Paper F6-1, Albuquerque, . . Mexico , (1978). 71391

  4. Rational Solution To Income Gap

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    While enjoying an economic boom, China has seen a widening income gap that has appeared like a chasm between its urban and rural citizens. What are the deep roots of this situation and what is the best way to deal with it? Ding Yuanzhu, researcher at the Macro-Economic Research Institute of the National Development and Reform Commission, shares his views on this issue in an article published in Wen Hui Bao. Excerpts follow:

  5. Closing the BME attainment gap

    OpenAIRE

    Nortcliffe, Anne; Pink-Keech, Cathy; Evans, Jayne

    2014-01-01

    The national British Minority Ethnic (BME) attainment gap is 16% (Berry and Loke, 2011). BME students frequently report being isolated and lonely (Cotton et al, 2011), and experience derisory support (NUS, 2011). At Sheffield Hallam University (SHU) a pilot Peer Assisted Learning (PAL) programme on an engineering course to aid inclusivity, as at UCL PAL has increased student retention (Angelini, 2011). The initial results at SHU are positive: "They [Mentors] kept me on a course and ...

  6. Prometheus and the Keeler gap

    Science.gov (United States)

    Tajeddine, Radwan; Nicholson, Phillip D.; Hedman, Matthew M.; French, Richard G.; Tiscareno, Matthew S.; Burns, Joseph A.

    2014-11-01

    Linblad resonances with Saturn’s satellites are located at many radii in the rings. While some cause density or bending waves, others hold gap edges from spreading, like the 2:1 resonance with Mimas located at the B-ring edge, the 7:6 resonance with Janus at the A-ring edge, and the 32:31 resonance with Prometheus at the inner edge of the Keeler gap. The latter is the case of study here.Theoretically, the inner edge of the Keeler gap should have 32 regular sinusoidal lobes, where either the maximum or the minimum radius is expected to be aligned with Prometheus and rotating with its mean motion. We show that such is not the case. Fit of occultation data shows the presence of the 32:31 resonance, however, the fit residuals is as high as the amplitude of the resonance amplitude (about 2 km). Analysis of the ISS data, shows irregularities overlapping the lobes (Tiscareno et al. 2005, DPS), that follow Keplerian motion. These irregularities may be due to clumps of particles with different eccentricities than the rest of the edge particles. This phenomenon may be caused by the resonance, as it has not been observed at other circular edges were no resonance is present at their location. The ISS data also shows that the lobe’s minimum/maximum is not perfectly aligned with the longitude of Prometheus, which may be due to libration about the centre of the resonance.

  7. Neutron stars versus black holes: probing the mass gap with LIGO/Virgo

    CERN Document Server

    Littenberg, Tyson B; Coughlin, Scott; Kalogera, Vicky; Holz, Daniel E

    2015-01-01

    The inspirals and mergers of binary systems comprised of black holes (BHs) and/or neutron stars (NSs) are expected to be abundant sources for ground-based gravitational-wave (GW) detectors. We assess the capabilities of Advanced LIGO and Virgo to measure component masses using inspiral waveform models which include spin-precession effects by studying a large ensemble of plausible GW sources. We make quantitative predictions for how well LIGO and Virgo will be able to distinguish between black holes and neutron stars and appraise the prospect of using LIGO/Virgo observations to definitively confirm, or reject, the existence of a putative "mass gap" between NSs ($m\\leq3\\ M_\\odot$) and BHs ($m\\geq 5\\ M_\\odot$). We find sources with the smaller mass component satisfying $m_2 \\lesssim1.5\\ M_\\odot$ to be unambiguously identified as containing at least one NS, while systems with $m_2\\gtrsim6\\ M_\\odot$ will be confirmed binary BHs. However, binary BHs with $m_2<5\\ M_\\odot$ (i.e., in the gap) cannot be distinguishe...

  8. 农用柴油机燃用生物质焦油与柴油混溶油性能实验%Performance Experiments of Miscible Oil Fueled with Biomass Tar and Diesel for Agricultural Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    张寰; 刘圣勇; 胡建军; 焦有宙; 张全国; 郭前辉

    2012-01-01

    New materials and equipment according to the combustible fraction of diesel miscible flammable characteristics of biomass tar was analyzed. Diesel engine fueled with different proportions of combustible biomass tar distillates and diesel miscible oil power performance was proposed. Experimental results showed that biomass tar combustible miscible distillate and diesel oil had good power and economy. When the power of agricultural diesel was low, the consumption of miscible oil sample was less than diesel. When the power of agricultural diesel was high, the consumption of miscible oil was less than diesel with the replacement ratio of 10% in diesel, but higher than diesel with replacement ratio of 20%. The maximum power of agricultural diesel engine with miscible oil was higher than the rated power of the agricultural diesel engines which met the power requirements of agricultural diesel engines.%根据生物质焦油中的可燃馏分与柴油互溶的可燃特性,研究了农用柴油机燃用不同比例的生物质焦油可燃馏分与柴油混溶油的动力性能,实验结果表明:生物质焦油可燃馏分与柴油混溶油具有良好的动力性和经济性,在农用柴油机功率较低时,各混溶油试样的消耗量均小于柴油;在农用柴油机功率较高时,生物质焦油可燃馏分掺混替代比例为10%时的混溶油消耗量低于柴油,而生物质焦油可燃馏分掺混替代比例为20%时的混溶油消耗量高于柴油,且燃用混溶油时农用柴油机的最大功率均超过农用柴油机的额定功率,可满足农用柴油机的动力要求.

  9. Selective dissolution in binary alloys

    Science.gov (United States)

    McCall, Carol Rene

    Corrosion is an important issue in the design of engineering alloys. De-alloying is an aspect of alloy corrosion related to the selective dissolution of one or more of the components in an alloy. The work reported herein focuses on the topic of de-alloying specific to single-phase binary noble metal alloy systems. The alloy systems investigated were gold-silver and gold-copper. The onset of a bulk selective dissolution process is typically marked by a critical potential whereby the more reactive component in the alloy begins dissolving from the bulk, leading to the formation of a bi-continuous solid-void morphology. The critical potential was investigated for the entire composition range of gold-silver alloys. The results presented herein include the formulation of an expression for critical potential as a function of both alloy and electrolyte composition. Results of the first investigation of underpotential deposition (UPD) on alloys are also presented herein. These results were implemented as an analytical tool to provide quantitative measurements of the surface evolution of gold during de-alloying. The region below the critical potential was investigated in terms of the compositional evolution of the alloy surface. Below the critical potential, there is a competition between the dissolution of the more reactive alloying constituent (either silver or copper) and surface diffusion of gold that serves to cover dissolution sites and prevent bulk dissolution. By holding the potential at a prescribed value below the critical potential, a time-dependent gold enrichment occurs on the alloy surface leading to passivation. A theoretical model was developed to predict the surface enrichment of gold based on the assumption of layer-by-layer dissolution of the more reactive alloy constituent. The UPD measurements were used to measure the time-dependent surface gold concentration and the results agreed with the predictions of the theoretical model.

  10. Parameters affecting gap detection in the rat.

    Science.gov (United States)

    Leitner, D S; Hammond, G R; Springer, C P; Ingham, K M; Mekilo, A M; Bodison, P R; Aranda, M T; Shawaryn, M A

    1993-09-01

    The present research used a startle amplitude reduction paradigm to investigate the ability of the rat's auditory system to track rapidly changing acoustic transients. Specifically examined was the ability of brief gaps in otherwise continuous noise to reduce the amplitude of a subsequently elicited acoustic startle reflex. The duration of the gap, time between gap offset and startle elicitation (the interstimulus interval or ISI), and rise-fall characteristics of the gap were systematically varied. Consistent with previous research, gaps reliably reduced startle amplitude. Gaps 2 msec long were reliably detected, and a 50-msec ISI resulted in the greatest amplitude reduction. Gaps presented at short ISIs produced amplitude reduction that followed a different time course than did gaps presented at longer ISIs. These results may reflect differences in the length of time available for the processing of the stimulus and may involve two different processes.

  11. A SEMIOLOGIC APPROACH TO AUDIT EXPECTATIONS GAP

    Directory of Open Access Journals (Sweden)

    Ciolpan Daniela

    2009-05-01

    Full Text Available Audit expectations gap (AEG is one of the most debated phenomena animating the international scientific research scene. The volume of papers focused on defining the AEG concept, examining its determinants, implications, and mechanisms to minimize the gap

  12. Exploring the Birth of Binary Stars

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    More than half of all stars are thought to be in binary or multiple star systems. But how do these systems form? The misaligned spins of some binary protostars might provide a clue.Two Formation ModelsIts hard to tell how multiple-star systems form, since these systems are difficult to observe in their early stages. But based on numerical simulations, there are two proposed models for the formation of stellar binaries:Turbulent fragmentationTurbulence within a single core leads to multiple dense clumps. These clumps independently collapse to form stars that orbit each other.Disk fragmentationGravitational instabilities in a massive accretion disk cause the formation of a smaller, secondary disk within the first, resulting in two stars that orbit each other.Log column density for one of the authors simulated binary systems, just after the formation of two protostars. Diamonds indicate the protostar positions. [Adapted from Offner et al. 2016]Outflows as CluesHow can we differentiate between these formation mechanisms? Led by Stella Offner (University of Massachusetts), a team of scientists has suggested that the key isto examine the alignment of the stars protostellar outflows jets that are often emitted from the poles of young, newly forming stars.Naively, wed expect that disk fragmentation would produce binary stars with common angular momentum. As the stars spins would be aligned, they would therefore also launch protostellar jets that were aligned with each other. Turbulent fragmentation, on the other hand, would cause the stars to have independent angular momentum. This would lead to randomly oriented spins, so the protostellar jets would be misaligned.Snapshots from the authors simulations. Left panel of each pair: column density; green arrows giveprotostellar spin directions. Right panel: synthetic observations produced from the simulations; cyan arrows giveprotostellar outflow directions. [Offner et al. 2016]Simulations of FragmentationIn order to better

  13. Absolute dimensions of eclipsing binaries XXVIII. BK pegasi and other F-type binaries

    DEFF Research Database (Denmark)

    Clausen, Jens Viggo; Frandsen, S.; Bruntt, H.

    2010-01-01

     stars: evolution / stars: fundamental parameters / binaries: eclipsing / stars: individual: BK¿Peg / stars: individual: BW¿Aqr / techniques: spectroscopic Udgivelsesdato: June 24...... stars: evolution / stars: fundamental parameters / binaries: eclipsing / stars: individual: BK¿Peg / stars: individual: BW¿Aqr / techniques: spectroscopic Udgivelsesdato: June 24...

  14. New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems

    CERN Document Server

    Bluhm, P; Vanzi, L; Soto, M G; Vos, J; Wittenmyer, R A; Olivares, F; Drass, H; Mennickent, R E; Vuckovic, M; Rojo, P; Melo, C H F

    2016-01-01

    We report the discovery of 24 spectroscopic binary companions to giant stars. We fully constrain the orbital solution for 6 of these systems. We cannot unambiguously derive the orbital elements for the remaining stars because the phase coverage is incomplete. Of these stars, 6 present radial velocity trends that are compatible with long-period brown dwarf companions.The orbital solutions of the 24 binary systems indicate that these giant binary systems have a wide range in orbital periods, eccentricities, and companion masses. For the binaries with restricted orbital solutions, we find a range of orbital periods of between $\\sim$ 97-1600 days and eccentricities of between $\\sim$ 0.1-0.4. In addition, we studied the metallicity distribution of single and binary giant stars. We computed the metallicity of a total of 395 evolved stars, 59 of wich are in binary systems. We find a flat distribution for these binary stars and therefore conclude that stellar binary systems, and potentially brown dwarfs, have a diffe...

  15. On the reconstruction of binary and permutation matrices under (binary) tomographic constraints

    NARCIS (Netherlands)

    Brunetti, S.; Del Lungo, A.; Gritzmann, P.; de Vries, S.

    2008-01-01

    The paper studies the problem of reconstructing binary matrices constrained by binary tomographic information. We prove new NP-hardness results that sharpen previous complexity results in the realm of discrete tomography but also allow applications to related problems for permutation matrices. Hence

  16. Towards the field binary population: Influence of orbital decay on close binaries

    CERN Document Server

    Korntreff, Christina; Pfalzner, Susanne

    2012-01-01

    Surveys of the binary populations in the solar neighbourhood have shown that the periods of G- and M-type stars are log-normally distributed. However, observations of young binary populations suggest a log-uniform distribution. Clearly some process(es) change the period distribution over time. Most stars form in star clusters, in which two important dynamical processes occur: i) gas-induced orbital decay of embedded binary systems and ii) destruction of soft binaries in three-body interactions. The emphasis here is on orbital decay which has been largely neglected so far. Using a combination of Monte-Carlo and dynamical nbody modelling it is demonstrated here that the cluster dynamics destroys the number of wide binaries, but leaves short-period binaries basically undisturbed even for a initially log-uniform distribution. By contrast orbital decay significantly reduces the number and changes the properties of short-period binaries, but leaves wide binaries largely uneffected. Until now it was unclear whether ...

  17. Birth of Massive Black Hole Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Colpi, M.; /Milan Bicocca U.; Dotti, M.; /Insubria U., Como; Mayer, L.; /Zurich, ETH; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  18. Gap Year: Time off, with a Plan

    Science.gov (United States)

    Torpey, Elka Maria

    2009-01-01

    A gap year allows people to step off the usual educational or career path and reassess their future. According to people who have taken a gap year, the time away can be well worth it. This article can help a person decide whether to take a gap year and how to make the most of his time off. It describes what a gap year is, including its pros and…

  19. "Explaining the Gender Wage Gap in Georgia"

    OpenAIRE

    Khitarishvili, Tamar

    2009-01-01

    This paper evaluates gender wage differentials in Georgia between 2000 and 2004. Using ordinary least squares, we find that the gender wage gap in Georgia is substantially higher than in other transition countries. Correcting for sample selection bias using the Heckman approach further increases the gender wage gap. The Blinder Oaxaca decomposition results suggest that most of the wage gap remains unexplained. The explained portion of the gap is almost entirely attributed to industrial variab...

  20. Massive gaseous discs around SMBH binaries: Binary decay and tidal disruptions

    Directory of Open Access Journals (Sweden)

    Brem P.

    2012-12-01

    Full Text Available We investigate the evolution of black hole binaries embedded within geometrically thin gas discs. Our results imply that such discs can produce black hole mergers for relatively low-mass binaries, and that a significant population of eccentric binaries might exist at separations of a few 0.01 pc. These binaries may be detectable due to the time-variable accretion on to the black holes. If the disc fragments, then the newly-born stars will continue driving the binary to its coalescence, although at a slower rate. Interestingly, our preliminary analysis shows that these stars will be disrupted at a rate of ∼10−4–2 · 10−5 events per year per system.