Pomeron models and exchange degeneracy of the Regge trajectories

International Nuclear Information System (INIS)

Kontros, J.; Kontros, K.; Lengyel, A.

2000-01-01

Two models for the Pomeron, supplemented by exchange-degenerate sub-leading Regge trajectories, are fitted to the forward scattering data for a number of reactions. By considering new Pomeron models, we extend the recent results of the COMPAS group, being consistent with our predecessors

On dark degeneracy and interacting models

International Nuclear Information System (INIS)

Carneiro, S.; Borges, H.A.

2014-01-01

Cosmological background observations cannot fix the dark energy equation of state, which is related to a degeneracy in the definition of the dark sector components. Here we show that this degeneracy can be broken at perturbation level by imposing two observational properties on dark matter. First, dark matter is defined as the clustering component we observe in large scale structures. This definition is meaningful only if dark energy is unperturbed, which is achieved if we additionally assume, as a second condition, that dark matter is cold, i.e. non-relativistic. As a consequence, dark energy models with equation-of-state parameter −1 ≤ ω < 0 are reduced to two observationally distinguishable classes with ω = −1, equally competitive when tested against observations. The first comprises the ΛCDM model with constant dark energy density. The second consists of interacting models with an energy flux from dark energy to dark matter

Parameter degeneracies in neutrino oscillation measurement of leptonic CP and T violation

International Nuclear Information System (INIS)

Minakata, Hisakazu; Nunokawa, Hiroshi; Parke, Stephen

2002-01-01

The measurement of the mixing angle θ 13 , sign of Δm 13 2 , and the CP or T violating phase δ is fraught with ambiguities in neutrino oscillation. In this paper we give an analytic treatment of the parameter degeneracies associated with measuring the ν μ →ν e probability and its CP and/or T conjugates. For CP violation, we give explicit solutions to allow us to obtain the regions where there exist twofold and fourfold degeneracies. We calculate the fractional differences, (Δθ/θ-bar), between the allowed solutions which may be used to compare with the expected sensitivities of the experiments. For T violation we show that there is always a complete degeneracy between solutions with positive and negative Δm 13 2 which arises due to a symmetry and cannot be removed by observing one neutrino oscillation probability and its T conjugate. Thus there is always a fourfold parameter degeneracy apart from exceptional points. Explicit solutions are also given and the fractional differences are computed. The biprobability CP/T trajectory diagrams are extensively used to illuminate the nature of the degeneracies

Accidental degeneracy of double Dirac cones in a phononic crystal

KAUST Repository

Chen, Ze-Guo; Ni, Xu; Wu, Ying; He, Cheng; Sun, Xiao-Chen; Zheng, Li-Yang; Lu, Ming-Hui; Chen, Yan-Feng

2014-01-01

Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect.

Accidental degeneracy of double Dirac cones in a phononic crystal

KAUST Repository

Chen, Ze-Guo

2014-04-09

Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect.

Dispersion in a thermal plasma including arbitrary degeneracy and quantum recoil.

Science.gov (United States)

Melrose, D B; Mushtaq, A

2010-11-01

The longitudinal response function for a thermal electron gas is calculated including two quantum effects exactly, degeneracy, and the quantum recoil. The Fermi-Dirac distribution is expanded in powers of a parameter that is small in the nondegenerate limit and the response function is evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum is performed in terms of polylogarithms in the long-wavelength and quasistatic limits, giving results that apply for arbitrary degeneracy. The results are applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the nondegenerate and completely degenerate limits, and generalizing them to arbitrary degeneracy.

Dispersion in thermal plasma including arbitrary degeneracy and quantum recoil

International Nuclear Information System (INIS)

Mushtaq, A.; Melrose, D.B.

2012-01-01

The longitudinal response function for a thermal electron gas was calculated including two quantum effects exactly, degeneracy and the quantum recoil. The Fermi-Dirac distribution was expanded in powers of a parameter that is small in the non-degenerate limit and the response function was evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum was performed in terms of poly logarithms in the long-wavelength and quasi-static limits, giving results that apply for arbitrary degeneracy. The results were applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the non-degenerate and completely degenerate limits], and generalizing them to arbitrary degeneracy. The occupation number for the completely degenerate limit is shown. The importance of the results regarding to semiconductor plasmas were highlighted. (orig./A.B.)

Physics reach of β-beams and ν-factories: the problem of degeneracies

International Nuclear Information System (INIS)

Rigolin, S.

2006-01-01

We discuss the physics reach of β-Beams and ν-Factories from a theoretical perspective, having as a guideline the problem of degeneracies. The presence of degenerate solutions in the measure of the neutrino oscillation parameters θ 13 and δ is, in fact, the main problem that have to be addressed in planning future neutrino oscillation experiments. If degeneracies are not (at least partially) solved, it will be almost impossible to perform, at any future facility, precise measurements of θ 13 and/or δ. After a pedagogical introduction on why degenerate solutions arise and how we can get rid of them, we analyze the physics reach of current β-beam and ν-factory configurations. The physics reach of the 'standard' β-Beam is severely affected by degeneracies while a better result can be obtained by higher-γ setups. At the ν-Factory the combination of Golden and Silver channels can solve the eightfold degeneracy down to sin 2 θ 13 = -3

Topological degeneracy of non-Abelian states for dummies

International Nuclear Information System (INIS)

Oshikawa, Masaki; Kim, Yong Baek; Shtengel, Kirill; Nayak, Chetan; Tewari, Sumanta

2007-01-01

We present a physical construction of degenerate groundstates of the Moore-Read Pfaffian states, which exhibits non-Abelian statistics, on general Riemann surface with genus g. The construction is given by a generalization of the recent argument [M.O., T. Senthil, Phys. Rev. Lett. 96 (2006) 060601] which relates fractionalization and topological order. The nontrivial groundstate degeneracy obtained by Read and Green [Phys. Rev. B 61 (2000) 10267] based on differential geometry is reproduced exactly. Some restrictions on the statistics, due to the fractional charge of the quasiparticle are also discussed. Furthermore, the groundstate degeneracy of the p + ip superconductor in two dimensions, which is closely related to the Pfaffian states, is discussed with a similar construction

Topological degeneracy of non-Abelian states for dummies

Science.gov (United States)

Oshikawa, Masaki; Kim, Yong Baek; Shtengel, Kirill; Nayak, Chetan; Tewari, Sumanta

2007-06-01

We present a physical construction of degenerate groundstates of the Moore-Read Pfaffian states, which exhibits non-Abelian statistics, on general Riemann surface with genus g. The construction is given by a generalization of the recent argument [M.O., T. Senthil, Phys. Rev. Lett. 96 (2006) 060601] which relates fractionalization and topological order. The nontrivial groundstate degeneracy obtained by Read and Green [Phys. Rev. B 61 (2000) 10267] based on differential geometry is reproduced exactly. Some restrictions on the statistics, due to the fractional charge of the quasiparticle are also discussed. Furthermore, the groundstate degeneracy of the p + i p superconductor in two dimensions, which is closely related to the Pfaffian states, is discussed with a similar construction.

Frequency degeneracy of acoustic waves in two-dimensional phononic crystals

International Nuclear Information System (INIS)

Darinskii, A N; Le Clezio, E; Feuillard, G

2007-01-01

Degeneracies of acoustic wave spectra in 2D phononic crystals (PC) and PC slabs are studied. A PC structure is constituted of parallel steel rods immersed into water and forming the quadratic lattice. Given the projection k z of the wave vector on the direction of rods, the bulk wave spectrum of the infinite PC is a set of frequency surfaces f i (k x , k y ), i = 1,2,..., where k x,y are the components of the wave vector in the plane perpendicular to the rods. An investigation is performed of the shape of frequency surfaces in the vicinity of points (k dx , k dy ), where these surfaces fall into contact. In addition, the evolution of the degeneracy with changing rod radius and cross-section shape is examined. Degeneracy in the spectrum of leaky modes propagating along a single waveguide in a PC slab is also investigated

Sfermion mass degeneracy, superconformal dynamics, and supersymmetric grand unified theories

International Nuclear Information System (INIS)

Kobayashi, Tatsuo; Noguchi, Tatsuya; Nakano, Hiroaki; Terao, Haruhiko

2002-01-01

We discuss issues in a scenario where hierarchical Yukawa couplings are generated through the strong dynamics of superconformal field theories (SCFTs). Independently of the mediation mechanism of supersymmetry breaking, the infrared convergence property of SCFTs can provide an interesting solution to the supersymmetric flavor problem; sfermion masses are suppressed around the decoupling scale of SCFTs and eventually become degenerate to some degree, thanks to family-independent radiative corrections governed by the gaugino masses of the minimal supersymmetric standard model (MSSM). We discuss under what conditions the degeneracy of the sfermion mass can be estimated in a simple manner. We also discuss the constraints from lepton flavor violations. We then explicitly study sfermion mass degeneracy within the framework of grand unified theories coupled to SCFTs. It is found that the degeneracy for right-handed sleptons becomes worse in the conventional SU(5) model than in the MSSM. On the other hand, in the flipped SU(5)xU(1) model, each right-handed lepton is still an SU(5) singlet, whereas the B-ino mass M 1 is determined by two independent gaugino masses of SU(5)xU(1). These two properties enable us to have an improved degeneracy for the right-handed sleptons. We also speculate on how further improvement can be obtained in the SCFT approach

Degeneración Lattice

OpenAIRE

Rojas Bocanegra, Alberto

2004-01-01

Objetivo: Determinar la prevalencia de degeneración periférica de retina Lattice y su relación con estados refractivos y rupturas retinales. Metodología: Estudio de corte transversal con exploración de asociación, mediante análisis de casos y controles. Se examinaron 680 ojos en el Instituto de Investigaciones Optométricas e Instituto de Córnea. El estado refractivo se determinó mediante técnica estática y el estado retinal mediante oftalmoscopia indirecta con indentación escleral. Resultados...

Frequency degeneracy of acoustic waves in two-dimensional phononic crystals

Energy Technology Data Exchange (ETDEWEB)

Darinskii, A N [Institute of Crystallography RAS, Leninskiy pr. 59, Moscow, 119333 (Russian Federation); Le Clezio, E [Universite Francois Rabelais de Tours, ENI Val de Loire, LUSSI, FRE CNRS 2448, rue de la Chocolaterie, BP3410, 41034 Blois (France); Feuillard, G [Universite Francois Rabelais de Tours, ENI Val de Loire, LUSSI, FRE CNRS 2448, rue de la Chocolaterie, BP3410, 41034 Blois (France)

2007-12-15

Degeneracies of acoustic wave spectra in 2D phononic crystals (PC) and PC slabs are studied. A PC structure is constituted of parallel steel rods immersed into water and forming the quadratic lattice. Given the projection k{sub z} of the wave vector on the direction of rods, the bulk wave spectrum of the infinite PC is a set of frequency surfaces f{sub i}(k{sub x}, k{sub y}), i = 1,2,..., where k{sub x,y} are the components of the wave vector in the plane perpendicular to the rods. An investigation is performed of the shape of frequency surfaces in the vicinity of points (k{sub dx}, k{sub dy}), where these surfaces fall into contact. In addition, the evolution of the degeneracy with changing rod radius and cross-section shape is examined. Degeneracy in the spectrum of leaky modes propagating along a single waveguide in a PC slab is also investigated.

Error correction and degeneracy in surface codes suffering loss

International Nuclear Information System (INIS)

Stace, Thomas M.; Barrett, Sean D.

2010-01-01

Many proposals for quantum information processing are subject to detectable loss errors. In this paper, we give a detailed account of recent results in which we showed that topological quantum memories can simultaneously tolerate both loss errors and computational errors, with a graceful tradeoff between the threshold for each. We further discuss a number of subtleties that arise when implementing error correction on topological memories. We particularly focus on the role played by degeneracy in the matching algorithms and present a systematic study of its effects on thresholds. We also discuss some of the implications of degeneracy for estimating phase transition temperatures in the random bond Ising model.

Degeneracy analysis for a supercell of a photonic crystal and its application to the creation of band gaps

International Nuclear Information System (INIS)

Wu Liang; Zhuang Fie; He Sailing

2003-01-01

A method is introduced to analyze the degeneracy properties of the band structure of a photonic crystal by making use of supercells. The band structure associated with a supercell of a photonic crystal has degeneracies at the edge of the Brillouin zone if the photonic crystal has some kind of point group symmetry. The E-polarization and H-polarization cases have the same degeneracies for a two-dimensional (2D) photonic crystal. Two theorems on degeneracies in the band structure associated with the supercell are given and proved. These degeneracies can be lifted to create photonic band gaps by changing the translation group symmetry of the photonic crystal (the point group symmetry of the photonic crystal may remain unchanged), which consequently changes the transform matrix between the supercell and the smallest unit cell. The existence of photonic band gaps for many known 2D photonic crystals is explained through the degeneracy analysis. Some structures with large band gaps are also found through the present degeneracy analysis

Single-centered black hole microstate degeneracies from instantons in supergravity

Science.gov (United States)

Murthy, Sameer; Reys, Valentin

2016-04-01

We obtain holographic constraints on the microscopic degeneracies of black holes by computing the exact macroscopic quantum entropy using localization, including the effects of string worldsheet instantons in the supergravity effective action. For 1/4 -BPS black holes in type II string theory on K3 × T 2, the constraints can be explicitly checked against expressions for the microscopic BPS counting functions that are known in terms of certain mock modular forms. We find that the effect of including the infinite sum over instantons in the holomorphic prepotential of the supergravity leads to a sum over Bessel functions with successively sub-leading arguments as in the Rademacher expansion of Jacobi forms — but begins to disagree with such a structure near an order where the mock modular nature becomes relevant. This leads to a systematic method to recover the polar terms of the microscopic degeneracies from the degeneracy of instantons (the Gromov-Witten invariants). We check explicitly that our formula agrees with the known microscopic answer for the first seven values of the magnetic charge invariant.

Single-centered black hole microstate degeneracies from instantons in supergravity

International Nuclear Information System (INIS)

Murthy, Sameer; Reys, Valentin

2016-01-01

We obtain holographic constraints on the microscopic degeneracies of black holes by computing the exact macroscopic quantum entropy using localization, including the effects of string worldsheet instantons in the supergravity effective action. For (1/4)-BPS black holes in type II string theory on K3×T 2 , the constraints can be explicitly checked against expressions for the microscopic BPS counting functions that are known in terms of certain mock modular forms. We find that the effect of including the infinite sum over instantons in the holomorphic prepotential of the supergravity leads to a sum over Bessel functions with successively sub-leading arguments as in the Rademacher expansion of Jacobi forms — but begins to disagree with such a structure near an order where the mock modular nature becomes relevant. This leads to a systematic method to recover the polar terms of the microscopic degeneracies from the degeneracy of instantons (the Gromov-Witten invariants). We check explicitly that our formula agrees with the known microscopic answer for the first seven values of the magnetic charge invariant.

Preasymptotical corrections to the pomeron exchange

International Nuclear Information System (INIS)

Volkovitskij, P.E.

1985-01-01

IN the frame of quark-gluon model for strong interactions, based on the topological expansion and string model, the planar diagrams are connected with Regge poles and the cylinder diagrams correspond to the pomeron. In earlier works it was shown that in this approach strong exchange degeneracy has to take place. This fact in the case of the pomeron with intercept αsub(D)(O)>1 is in disagreement with experiment. In the present paper the preasymptotical corrections to the pomeron exchange are calculated. It is shown that these corrections remove the dissagreement

On the degeneracy of the IMRT optimization problem

International Nuclear Information System (INIS)

Alber, M.; Meedt, G.; Nuesslin, F.; Reemtsen, R.

2002-01-01

One approach to the computation of photon IMRT treatment plans is the formulation of an optimization problem with an objective function that derives from an objective density. An investigation of the second-order properties of such an objective function in a neighborhood of the minimizer opens an intuitive access to many traits of this approach. A general finding is that only a small subset of the parameter space has nonzero curvature, while the objective function is entirely flat in a neighborhood of the minimizer in most directions. The dimension of the subspace of vanishing curvature serves as a measure for the degeneracy of the solution. This finding is important both for algorithm design and evaluation of the mathematical model of clinical intuition, expressed by the objective function. The structure of the subspace of great curvature is found to be imposed on the problem by conflicts between objectives of target and critical structures. These conflicts and their corresponding modes of resolution form a common trait between all reasonable treatment plans of a given case. The high degree of degeneracy makes the use of a conjugate gradient optimization algorithm particularly favorable since the number of iterations to convergence is equivalent to the number of different eigenvalues of the curvature tensor and is hence independent from the number of optimization parameters. A high level of degeneracy of the fluence profiles implies that it should be possible to stipulate further delivery-related conditions without causing severe deterioration of the dose distribution

Rotational Spectral Unmixing of Exoplanets: Degeneracies between Surface Colors and Geography

Energy Technology Data Exchange (ETDEWEB)

Fujii, Yuka [NASA Goddard Institute for Space Studies, New York, NY 10025 (United States); Lustig-Yaeger, Jacob [Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195 (United States); Cowan, Nicolas B., E-mail: yuka.fujii.ebihara@gmail.com [Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, H3A 0E8 (Canada)

2017-11-01

Unmixing the disk-integrated spectra of exoplanets provides hints about heterogeneous surfaces that we cannot directly resolve in the foreseeable future. It is particularly important for terrestrial planets with diverse surface compositions like Earth. Although previous work on unmixing the spectra of Earth from disk-integrated multi-band light curves appeared successful, we point out a mathematical degeneracy between the surface colors and their spatial distributions. Nevertheless, useful constraints on the spectral shape of individual surface types may be obtained from the premise that albedo is everywhere between 0 and 1. We demonstrate the degeneracy and the possible constraints using both mock data based on a toy model of Earth, as well as real observations of Earth. Despite the severe degeneracy, we are still able to recover an approximate albedo spectrum for an ocean. In general, we find that surfaces are easier to identify when they cover a large fraction of the planet and when their spectra approach zero or unity in certain bands.

Rotational Spectral Unmixing of Exoplanets: Degeneracies Between Surface Colors and Geography

Science.gov (United States)

Fujii, Yuka; Lustig-Yaeger, Jacob; Cowan, Nicolas B.

2017-01-01

Unmixing the disk-integrated spectra of exoplanets provides hints about heterogeneous surfaces that we cannot directly resolve in the foreseeable future. It is particularly important for terrestrial planets with diverse surface compositions like Earth. Although previous work on unmixing the spectra of Earth from disk-integrated multi-band light curves appeared successful, we point out a mathematical degeneracy between the surface colors and their spatial distributions. Nevertheless, useful constraints on the spectral shape of individual surface types may be obtained from the premise that albedo is everywhere between 0 and 1. We demonstrate the degeneracy and the possible constraints using both mock data based on a toy model of Earth, as well as real observations of Earth. Despite the severe degeneracy, we are still able to recover an approximate albedo spectrum for an ocean. In general, we find that surfaces are easier to identify when they cover a large fraction of the planet and when their spectra approach zero or unity in certain bands.

Lattice degeneracies of fermions

International Nuclear Information System (INIS)

Raszillier, H.

1983-10-01

We present a detailed description of the minimal degeneracies of geometric (Kaehler) fermions on all the lattices of maximal symmetries in n = 1, ..., 4 dimensions. We also determine the isolated orbits of the maximal symmetry groups, which are related to the minimal numbers of ''naive'' fermions on the reciprocals of these lattices. It turns out that on the self-reciprocal lattices the minimal numbers of naive fermions are equal to the minimal numbers of degrees of freedom of geometric fermions. The description we give relies on the close connection of the maximal lattice symmetry groups with (affine) Weyl groups of root systems of (semi-) simple Lie algebras. (orig.)

Effect of electron degeneracy on fast-particles energy deposition in dense plasma systems

International Nuclear Information System (INIS)

Johzaki, T.; Nakao, Y.; Nakashima, H.; Kudo, K.

1997-01-01

The effects of electron degeneracy on fast-particles energy deposition in dense plasmas are investigated by making transport calculations for the fast particles. It is found that the degeneracy substantially affects the profiles of energy deposition of 3.52-MeV α-particles. On the other hand, the effect on the energy deposition of 14.1-MeV neutrons is negligibly small because the recoil ions, which transfer the neutron energy to the plasma constituents, are produced in a whole plasma volume due to the long mean-free-path of neutrons. The coupled transport-hydrodynamic calculations show that these effects of degeneracy are negligible in the ignition and burn characteristics of central ignition D-T targets. (author)

Accidental degeneracy in k-space, geometrical phase, and the perturbation of π by spin-orbit interactions

Science.gov (United States)

Allen, Philip B.; Pickett, Warren E.

2018-06-01

Since closed lines of accidental electronic degeneracies were demonstrated to be possible, even frequent, by Herring in 1937, no further developments arose for eight decades. The earliest report of such a nodal loop in a real material - aluminum - is recounted and elaborated on. Nodal loop semimetals have become a focus of recent activity, with emphasis on other issues. Band degeneracies are, after all, the origin of topological phases in crystalline materials. Spin-orbit interaction lifts accidental band degeneracies, with the resulting spectrum being provided here. The geometric phase γ(C) = ± π for circuits C surrounding a line of such degeneracy cannot survive completely unchanged. The change depends on how the spin is fixed during adiabatic evolution. For spin fixed along the internal spin-orbit field, γ(C) decreases to zero as the circuit collapses around the line of lifted degeneracy. For spin fixed along a perpendicular axis, the conical intersection persists and γ(C) = ± π is unchanged.

SPIN-PRECESSION: BREAKING THE BLACK HOLE-NEUTRON STAR DEGENERACY

Energy Technology Data Exchange (ETDEWEB)

Chatziioannou, Katerina; Cornish, Neil; Klein, Antoine; Yunes, Nicolás [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2015-01-01

Mergers of compact stellar remnants are prime targets for the LIGO/Virgo gravitational wave detectors. The gravitational wave signals from these merger events can be used to study the mass and spin distribution of stellar remnants, and provide information about black hole horizons and the material properties of neutron stars. However, it has been suggested that degeneracies in the way that the star's mass and spin are imprinted in the waveforms may make it impossible to distinguish between black holes and neutron stars. Here we show that the precession of the orbital plane due to spin-orbit coupling breaks the mass-spin degeneracy, and allows us to distinguish between standard neutron stars and alternative possibilities, such as black holes or exotic neutron stars with large masses and spins.

Degeneracy of the lowest Landau level and suq(2) on the Poincare half plane

International Nuclear Information System (INIS)

Jellal, A.

2000-01-01

It is shown that the presence of the quantum group symmetry su q (2) in the quantum Hall effect on the Poincare upper half plane the degeneracy of the lowest Landau level. It is also shown that the relation between the degeneracy and the cyclic representation of su q (2) appears in accordance with q being a kth root of unity. (Authors)

Constraints on neutrino degeneracy from the cosmic microwave background and primordial nucleosynthesis

International Nuclear Information System (INIS)

Orito, M.; Kajino, T.; Mathews, G. J.; Wang, Y.

2002-01-01

We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy based upon the latest high resolution CMB sky maps from BOOMERANG, DASI, and MAXIMA-1. We generate likelihood functions by marginalizing over (Ω b h 2 ,ξ ν μ,τ ,ξ ν e ,Ω Λ ,h,n) plus the calibration uncertainties. We consider flat Ω M +Ω Λ =1 cosmological models with two identical degenerate neutrino species, ξ ν μ,τ ≡ vertical bar ξ ν μ vertical bar = vertical bar ξ ν τ vertical bar and a small ξ ν e . We assign weak top-hat priors on the electron-neutrino degeneracy parameter ξ ν e and Ω b h 2 based upon allowed values consistent with the nucleosynthesis constraints as a function of ξ ν μ,τ . The change in the background neutrino temperature with degeneracy is also explicitly included, and Gaussian priors for h=0.72±0.08 and the experimental calibration uncertainties are adopted. The marginalized likelihood functions show a slight (0.5σ) preference for neutrino degeneracy. Optimum values with two equally degenerate μ and τ neutrinos imply ξ ν μ,τ =1.0 -1.0(0.5σ) +0.8(1σ) ,from which we deduce ξ ν e =0.09 -0.09 +0.15 , and Ω b h 2 =0.021 -0.002 +0.06 . The 2σ upper limit becomes ξ ν μ,τ ≤2.1, which implies ξ ν e ≤0.30, and Ω b h 2 ≤0.030. For only a single large-degeneracy species the optimal value is vertical bar ξ ν μ vertical bar or vertical bar ξ ν τ vertical bar =1.4 with a 2σ upper limit of vertical bar ξ ν μ vertical bar or vertical bar ξ ν τ vertical bar ≤2.5.

CORECLUSTER: A Degeneracy Based Graph Clustering Framework

OpenAIRE

Giatsidis , Christos; Malliaros , Fragkiskos; Thilikos , Dimitrios M. ,; Vazirgiannis , Michalis

2014-01-01

International audience; Graph clustering or community detection constitutes an important task forinvestigating the internal structure of graphs, with a plethora of applications in several domains. Traditional tools for graph clustering, such asspectral methods, typically suffer from high time and space complexity. In thisarticle, we present \\textsc{CoreCluster}, an efficient graph clusteringframework based on the concept of graph degeneracy, that can be used along withany known graph clusteri...

Degeneracy of energy levels of pseudo-Gaussian oscillators

International Nuclear Information System (INIS)

Iacob, Theodor-Felix; Iacob, Felix; Lute, Marina

2015-01-01

We study the main features of the isotropic radial pseudo-Gaussian oscillators spectral properties. This study is made upon the energy levels degeneracy with respect to orbital angular momentum quantum number. In a previous work [6] we have shown that the pseudo-Gaussian oscillators belong to the class of quasi-exactly solvable models and an exact solution has been found

The Disk Mass Project: breaking the disk-halo degeneracy

NARCIS (Netherlands)

Verheijen, Marc A. W.; Bershady, Matthew A.; Swaters, Rob A.; Andersen, David R.; Westfall, Kyle B.; DE JONG, R. S.

2007-01-01

Little is known about the content and distribution of dark matter in spiral galaxies. To break the degeneracy in galaxy rotation curve decompositions, which allows a wide range of dark matter halo density profiles, an independent measure of the mass surface density of stellar disks is needed. Here,

Close near-degeneracy in a pair of four-quasiparticle bands in 194Tl

International Nuclear Information System (INIS)

Masiteng, P.L.; Lawrie, E.A.; Ramashidzha, T.M.; Bark, R.A.; Carlsson, B.G.; Lawrie, J.J.; Lindsay, R.; Komati, F.; Kau, J.; Maine, P.; Maliage, S.M.; Matamba, I.; Mullins, S.M.; Murray, S.H.T.; Mutshena, K.P.; Pasternak, A.A.; Ragnarsson, I.

2013-01-01

A pair of rotational bands associated with the πh 9/2 ⊗νi 13/2 −1 configuration at lower spins and with the πh 9/2 ⊗νi 13/2 −3 configuration at higher spins is found in 194 Tl. The two 4-quasiparticle bands show exceptionally close near-degeneracy in the excitation energies. Furthermore close similarity is also found in their alignments and B(M1)/B(E2) reduced transition probability ratios. Such close near-degeneracy probably indicates chiral geometry in the angular momentum space

A NEW APPLICATION OF THE ASTROMETRIC METHOD TO BREAK SEVERE DEGENERACIES IN BINARY MICROLENSING EVENTS

International Nuclear Information System (INIS)

Chung, Sun-Ju; Park, Byeong-Gon; Humphrey, Andrew; Ryu, Yoon-Hyun

2009-01-01

When a source star is microlensed by one stellar component of widely separated binary stellar components, after finishing the lensing event, the event induced by the other binary star can be additionally detected. In this paper, we investigate whether the close/wide degeneracies in binary lensing events can be resolved by detecting the additional centroid shift of the source images induced by the secondary binary star in wide binary lensing events. From this investigation, we find that if the source star passes close to the Einstein ring of the secondary companion, the degeneracy can be easily resolved by using future astrometric follow-up observations with high astrometric precision. We determine the probability of detecting the additional centroid shift in binary lensing events with high magnification. From this, we find that the degeneracy of binary lensing events with a separation of ∼<20.0 AU can be resolved with a significant efficiency. We also estimate the waiting time for the detection of the additional centroid shift in wide binary lensing events. We find that for typical Galactic lensing events with a separation of ∼<20.0 AU, the additional centroid shift can be detected within 100 days, and thus the degeneracy of those events can be sufficiently broken within a year.

Black hole state degeneracy in loop quantum gravity

International Nuclear Information System (INIS)

Agullo, Ivan; Diaz-Polo, Jacobo; Fernandez-Borja, Enrique

2008-01-01

The combinatorial problem of counting the black hole quantum states within the isolated horizon framework in loop quantum gravity is analyzed. A qualitative understanding of the origin of the band structure shown by the degeneracy spectrum, which is responsible for the black hole entropy quantization, is reached. Even when motivated by simple considerations, this picture allows to obtain analytical expressions for the most relevant quantities associated to this effect

Effect of exchange correlation potential on dispersion properties of lower hybrid wave in degenerate plasma

Science.gov (United States)

Rimza, Tripti; Sharma, Prerana

2017-05-01

The dispersion properties of lower hybrid wave are studied in electron-iondegenerate plasma with exchange effect in non-relativistic regime. It is found that the combined effect of Bohm potential and exchange correlation potential significantly modifies the dispersion properties of lower hybrid wave. The graphical results explicitly show the influence of degeneracy pressure, Bohm force and exchange correlation potential on the frequency of the lower hybrid mode. Present work should be of relevance for the dense astrophysical environments like white dwarfs and for laboratory experiments.

Adenoma tiroidiano con sospecha de degeneración maligna

Directory of Open Access Journals (Sweden)

Manuel José Luque

1944-11-01

III El autor describe la intervención quirúrgica y anota los hallazgos del acto operatorio. Se hizo una estirpación meticulosa de todas las formaciones ganglionares. IV Transcribe día a día el post operatorio y termina con unas breves consideraciones sobre la degeneración neoplásica del cuerpo tiroides.

OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing Degeneracy

Science.gov (United States)

Skowron, J.; Ryu, Y.-H.; Hwang, K.-H.; Udalski, A.; Mrǎłz, P.; Kozłowski, S.; Soszyński, I.; Pietrukowicz, P.; Szymański, P. K.; Poleski, R.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; Albrow, M. D.; Chung, S.-J.; Gould, A.; Han, C.; Jung, Y. K.; Shin, I.-G.; Shvartzvald, Y.; Yee, J. C.; Zang, W.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.

2018-03-01

We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor 2.5 difference in planet-host mass ratio, i.e., q=1.5×10-3 vs. q=0.6×10-3. We show that this is an "accidental degeneracy" in the sense that it is due to a gap in the data. We dub it "the caustic-chirality degeneracy". We trace the mathematical origins of this degeneracy, which should enable similar degenerate solutions to be easily located in the future. A Bayesian estimate, based on a Galactic model, yields a host mass M=0.25+0.30-0.15 M⊙ at a distance DL=5.9+1.3-1.95 kpc. The lens-source relative proper motion is relatively fast, μ=9 mas/yr, which implies that the host mass and distance can be determined by high-resolution imaging after about 10 years. The same observations could in principle resolve the discrete degeneracy in q, but this will be more challenging.

Time-Dependent Global Sensitivity Analysis for Long-Term Degeneracy Model Using Polynomial Chaos

Directory of Open Access Journals (Sweden)

Jianbin Guo

2014-07-01

Full Text Available Global sensitivity is used to quantify the influence of uncertain model inputs on the output variability of static models in general. However, very few approaches can be applied for the sensitivity analysis of long-term degeneracy models, as far as time-dependent reliability is concerned. The reason is that the static sensitivity may not reflect the completed sensitivity during the entire life circle. This paper presents time-dependent global sensitivity analysis for long-term degeneracy models based on polynomial chaos expansion (PCE. Sobol’ indices are employed as the time-dependent global sensitivity since they provide accurate information on the selected uncertain inputs. In order to compute Sobol’ indices more efficiently, this paper proposes a moving least squares (MLS method to obtain the time-dependent PCE coefficients with acceptable simulation effort. Then Sobol’ indices can be calculated analytically as a postprocessing of the time-dependent PCE coefficients with almost no additional cost. A test case is used to show how to conduct the proposed method, then this approach is applied to an engineering case, and the time-dependent global sensitivity is obtained for the long-term degeneracy mechanism model.

Quantum degeneracy effect on performance of irreversible Otto cycle with ideal Bose gas

International Nuclear Information System (INIS)

Wu Feng; Chen Lingen; Sun Fengrui; Wu Chih; Guo Fangzhong; Li Qing

2006-01-01

An Otto cycle working with an ideal Bose gas is called a Bose Otto cycle. The internal irreversibility of the cycle is included in the factors of internal irreversibility degree. The quantum degeneracy effect on the performance of the cycle is investigated based on quantum statistical mechanics and thermodynamics. Variations of the maximum work output ratio R W and the efficiency ratio y with temperature ratio τ are examined, which reveal the influence of the quantum degeneracy of the working substance on the performance of a Bose Otto cycle. It is shown that the results obtained herein are valid under both classical and quantum ideal gas conditions

Quantum degeneracy corrections to plasma line emission and to Saha equation

International Nuclear Information System (INIS)

Molinari, V.G.; Mostacci, D.; Rocchi, F.; Sumini, M.

2003-01-01

The effect of quantum degeneracy on the electron collisional excitation is investigated, and its effects on line emission evaluated for applications to spectroscopy of dense, cold plasmas. A correction to Saha equation for weakly-degenerate plasmas is also presented

Energy exchange in strongly coupled plasmas with electron drift

International Nuclear Information System (INIS)

Akbari-Moghanjoughi, M.; Ghorbanalilu, M.

2015-01-01

In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum plasma in the presence of strong electron-beam plasma interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the electron-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of plasma number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the electron-ion collision frequencies are used for strongly coupled ion fluid. The effect of the electron-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in plasmas. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum plasma. The effect of many independent plasma parameters, such as the ion charge-state, electron beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of plasma instability or energy loss/gain of the electron-beam

Perturbing free motions on hyperspheres without degeneracy lift

International Nuclear Information System (INIS)

Pallares-Rivera, A; Rosales-Aldape, F de J; Kirchbach, M

2014-01-01

We consider quantum motion on S 3 perturbed by the trigonometric Scarf potential (Scarf I) with one internal quantized dimensionless parameter, ℓ, the ordinary orbital angular momentum value, and another continuous parameter, b, through which an external scale is introduced. We argue that a loss of the geometric hyperspherical so(4) symmetry of the free motion occurs that leaves intact the unperturbed hydrogen-like degeneracy patterns characterizing the spectrum under discussion. The argument is based on the observation that the expansions of the Scarf I wave functions for fixed ℓ-values on the basis of properly identified so(4) representation functions are power series in the perturbation parameter, b, in which carrier spaces of dimensionality (K + 1) 2 with K varying as K ∈ [ℓ, N − 1], and N being the principal quantum number of the Scarf I potential problem, contribute up to the order O(b N−1−K ). Nonetheless, the degeneracy patterns can still be interpreted as a consequence of an effective so(4) symmetry, i.e. a symmetry realized at the level of the dynamic of the system, in so far as from the perspective of the eigenvalue problem, the Scarf I Hamiltonian results are equivalent to a Hamiltonian whose matrix elements are polynomials in a properly identified so(4) Casimir operator. The scheme applies to any dimension d. (paper)

Degeneracy. Languages’ strategy to withstand stress (invited talk)

OpenAIRE

Van de Velde, Freek

2017-01-01

Like the stock market, cities, or ant colonies, language is a complex adaptive system (Holland 1992; Beckner et al. 2009; Bybee 2010). One of the properties of such systems is that they rely on what in biology is called ‘degeneracy’. In this context, degeneracy has nothing to do with its common sense meaning of deterioration, but is a technical term for the phenomenon that structurally different elements or strategies can fulfill the same function (see Edelman & Gally 2001). A simple example ...

Generators with interior degeneracy on spaces of L^2 type

Directory of Open Access Journals (Sweden)

Genni Fragnelli

2012-10-01

Full Text Available We consider operators in divergence and in nondivergence form with degeneracy at the interior of the space domain. Characterizing the domain of the operators, we prove that they generate positive analytic semigroups on spaces of L^2 type. Finally, some applications to linear and semilinear parabolic evolution problems and to linear hyperbolic ones are presented.

Exchange interactions in two-state systems: rare earth pyrochlores

Science.gov (United States)

Curnoe, S. H.

2018-06-01

The general form of the nearest neighbour exchange interaction for rare earth pyrochlores is derived based on symmetry. Generally, the rare earth angular momentum degeneracy is lifted by the crystal electric field (CEF) into singlets and doublets. When the CEF ground state is a doublet that is well-separated from the first excited state the CEF ground state doublet can be treated as a pseudo-spin of some kind. The general form of the nearest neighbour exchange interaction for pseudo-spins on the pyrochlore lattice is derived for three different types of pseudo-spins. The methodology presented in this paper can be applied to other two-state spin systems with a high space group symmetry.

Degeneracy: a link between evolvability, robustness and complexity in biological systems

Directory of Open Access Journals (Sweden)

Whitacre James M

2010-02-01

Full Text Available Abstract A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability and evidence of an intimate relationship between robustness and complexity in biology. This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability.

Degeneracy, frequency response and filtering in IMRT optimization

International Nuclear Information System (INIS)

Llacer, Jorge; Agazaryan, Nzhde; Solberg, Timothy D; Promberger, Claus

2004-01-01

This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of optimizations, effects of initial beamlet fluence assignment and stopping point, what does filtering of an optimized beamlet map actually do and how could image analysis help to obtain better optimizations? Two target functions are studied, a quadratic cost function and the log likelihood function of the dynamically penalized likelihood (DPL) algorithm. The algorithms used are the conjugate gradient, the stochastic adaptive simulated annealing and the DPL. One simple phantom is used to show the development of the analysis tools used and two clinical cases of medium and large dose matrix size (a meningioma and a prostate) are studied in detail. The conclusions reached are that the high number of iterations that is needed to avoid degeneracy is not warranted in clinical practice, as the quality of the optimizations, as judged by the DVHs and dose distributions obtained, does not improve significantly after a certain point. It is also shown that the optimum initial beamlet fluence assignment for analytical iterative algorithms is a uniform distribution, but such an assignment does not help a stochastic method of optimization. Stopping points for the studied algorithms are discussed and the deterioration of DVH characteristics with filtering is shown to be partially recoverable by the use of space-variant filtering techniques

Degeneracy, frequency response and filtering in IMRT optimization

Energy Technology Data Exchange (ETDEWEB)

Llacer, Jorge [EC Engineering Consultants LLC, 130 Forest Hill Drive, Los Gatos, CA 95032 (United States); Agazaryan, Nzhde [Department of Radiation Oncology, University of California, Los Angeles, CA 90095 (United States); Solberg, Timothy D [Department of Radiation Oncology, University of California, Los Angeles, CA 90095 (United States); Promberger, Claus [BrainLAB AG, Ammerthalstrasse 8, 85551 Heimstetten (Germany)

2004-07-07

This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of optimizations, effects of initial beamlet fluence assignment and stopping point, what does filtering of an optimized beamlet map actually do and how could image analysis help to obtain better optimizations? Two target functions are studied, a quadratic cost function and the log likelihood function of the dynamically penalized likelihood (DPL) algorithm. The algorithms used are the conjugate gradient, the stochastic adaptive simulated annealing and the DPL. One simple phantom is used to show the development of the analysis tools used and two clinical cases of medium and large dose matrix size (a meningioma and a prostate) are studied in detail. The conclusions reached are that the high number of iterations that is needed to avoid degeneracy is not warranted in clinical practice, as the quality of the optimizations, as judged by the DVHs and dose distributions obtained, does not improve significantly after a certain point. It is also shown that the optimum initial beamlet fluence assignment for analytical iterative algorithms is a uniform distribution, but such an assignment does not help a stochastic method of optimization. Stopping points for the studied algorithms are discussed and the deterioration of DVH characteristics with filtering is shown to be partially recoverable by the use of space-variant filtering techniques.

Communication: Effect of accidental mode degeneracy on Raman intensity in 2D materials: Hybrid functional study of bilayer phosphorene

Energy Technology Data Exchange (ETDEWEB)

Sun, Yi-Yang; Zhang, Shengbai [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2016-07-14

Bulk black phosphorus has two optical phonon modes labeled as A{sub g}{sup 2} and B{sub 2u}, respectively, that are nearly degenerate in frequency. However, density functional theory calculations using local or semi-local functionals cannot reproduce this degeneracy. Here, we propose a hybrid functional approach aided by van der Waals (vdW) force fields, which can accurately describe the lattice dynamic and electronic properties of both bulk and few-layer black phosphorus (phosphorene). Using this approach we show that in bilayer phosphorene, the two Raman modes derived from the B{sub 2u} and A{sub g}{sup 2} modes could exhibit strong resonance as a result of the accidental degeneracy so that both modes could be observed in Raman experiment. Without the mode degeneracy, however, the Raman intensity of the B{sub 2u}-derived mode would be too weak to be observed. We further show that the accidental degeneracy is correlated to the applied strain, which enables Raman spectroscopy to be a powerful tool for characterizing built-in strains in 2D materials, e.g., due to the interaction with substrates, which has emerged as an important issue in vdW epitaxy.

Degeneración macular relacionada a la edad

OpenAIRE

Juan Verdaguer, T.

2010-01-01

La degeneración macular relacionada a la edad es la causa más frecuente de pérdida de visión irreversible en personas mayores de 60 años. Son factores de riesgo la edad, la genética, el tabaquismo y la obesidad abdominal. Su primera manifestación visible son las drusas, acumulación de productos provenientes de la degradación incompleta de la digestión de segmentos de fotoreceptores por el epitelio pigmentario. La administración de antioxidantes y zinc disminuye el riesgo de pérdida severa de ...

Symmetry and fermion degeneracy on a lattice

International Nuclear Information System (INIS)

Raszillier, H.

1982-03-01

In this paper we consider the general form of finite difference approximation to the Dirac (Weyl) Hamiltonian on a lattice and investigate systematically the dependence on symmetry of the number of particles described by it. Our result is, that to a symmetry - expressed by a crystallographic space group - there corresponds a minimal number of particles, which are associated to prescribed points of momentum space (the unit cell of the reciprocal lattice). For convenience of the reader we show, using the existing detailed descriptions of space groups, how these results look for all the relevant (symmorphic) symmetry groups. Only for lattice Hamiltonians with a momentum dependent mass term can this degeneracy be reduced and even eliminated without reducing the symmetry. (orig./HSI)

Landau degeneracy and black hole entropy

International Nuclear Information System (INIS)

Costa, M.S.; Perry, M.J.

1998-01-01

We consider the supergravity solution describing a configuration of intersecting D4-branes with non-vanishing world-volume gauge fields. The entropy of such a black hole is calculated in terms of the D-branes quantised charges. The non-extreme solution is also considered and the corresponding thermodynamical quantities are calculated in terms of a D-brane/anti-D-brane system. To perform the quantum mechanical D-brane analysis we study open strings with their ends on branes with a magnetic condensate. Applying the results to our D-brane system we manage to have a perfect agreement between the D-brane entropy counting and the corresponding semi-classical result. The Landau degeneracy of the open string states describing the excitations of the D-brane system enters in a crucial way. We also derive the near-extreme results which agree with the semi-classical calculations. (orig.)

Chemical potentials and thermodynamic characteristics of ideal Bose- and Fermi-gases in the region of quantum degeneracy

Science.gov (United States)

Sotnikov, A. G.; Sereda, K. V.; Slyusarenko, Yu. V.

2017-01-01

Calculations of chemical potentials for ideal monatomic gases with Bose-Einstein and Fermi-Dirac statistics as functions of temperature, across the temperature region that is typical for the collective quantum degeneracy effect, are presented. Numerical calculations are performed without any additional approximations, and explicit dependences of the chemical potentials on temperature are constructed at a fixed density of gas particles. Approximate polynomial dependences of chemical potentials on temperature are obtained that allow for the results to be used in further studies without re-applying the involved numerical methods. The ease of using the obtained representations is demonstrated on examples of deformation of distribution for a population of energy states at low temperatures, and on the impact of quantum statistics (exchange interaction) on the equations of state for ideal gases and some of the thermodynamic properties thereof. The results of this study essentially unify two opposite limiting cases in an intermediate region that are used to describe the equilibrium states of ideal gases, which are well known from university courses on statistical physics, thus adding value from an educational point of view.

Symmetry and Degeneracy in Quantum Mechanics. Self-Duality in Finite Spin Systems

Science.gov (United States)

Osacar, C.; Pacheco, A. F.

2009-01-01

The symmetry of self-duality (Savit 1980 "Rev. Mod. Phys. 52" 453) of some models of statistical mechanics and quantum field theory is discussed for finite spin blocks of the Ising chain in a transverse magnetic field. The existence of this symmetry in a specific type of these blocks, and not in others, is manifest by the degeneracy of their…

Quantum dust magnetosonic waves with spin and exchange correlation effects

Energy Technology Data Exchange (ETDEWEB)

Maroof, R.; Qamar, A. [Department of Physics, University of Peshawar, Peshawar 25000 (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan); National Center for Physics, Shahdra Valley Road, Islamabad 44000 (Pakistan)

2016-01-15

Dust magnetosonic waves are studied in degenerate dusty plasmas with spin and exchange correlation effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, spin magnetization energy, and exchange correlation, a generalized dispersion relation is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. The exchange-correlation potentials are used, based on the adiabatic local-density approximation, and can be described as a function of the electron density. For three different values of angle, the dispersion relation is reduced to three different modes under the low frequency magnetohydrodynamic assumptions. It is found that the effects of quantum corrections in the presence of dust concentration significantly modify the dispersive properties of these modes. The results are useful for understanding numerous collective phenomena in quantum plasmas, such as those in compact astrophysical objects (e.g., the cores of white dwarf stars and giant planets) and in plasma-assisted nanotechnology (e.g., quantum diodes, quantum free-electron lasers, etc.)

Quantum dust magnetosonic waves with spin and exchange correlation effects

Science.gov (United States)

Maroof, R.; Mushtaq, A.; Qamar, A.

2016-01-01

Dust magnetosonic waves are studied in degenerate dusty plasmas with spin and exchange correlation effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, spin magnetization energy, and exchange correlation, a generalized dispersion relation is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. The exchange-correlation potentials are used, based on the adiabatic local-density approximation, and can be described as a function of the electron density. For three different values of angle, the dispersion relation is reduced to three different modes under the low frequency magnetohydrodynamic assumptions. It is found that the effects of quantum corrections in the presence of dust concentration significantly modify the dispersive properties of these modes. The results are useful for understanding numerous collective phenomena in quantum plasmas, such as those in compact astrophysical objects (e.g., the cores of white dwarf stars and giant planets) and in plasma-assisted nanotechnology (e.g., quantum diodes, quantum free-electron lasers, etc.).

SPACE-BASED MICROLENS PARALLAX OBSERVATION AS A WAY TO RESOLVE THE SEVERE DEGENERACY BETWEEN MICROLENS-PARALLAX AND LENS-ORBITAL EFFECTS

Energy Technology Data Exchange (ETDEWEB)

Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Pawlak, M. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Lee, C.-U.; Gould, A.; Chung, S.-J.; Kim, S.-L.; Cha, S.-M. [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Bozza, V. [Dipartimento di Fisica “E. R. Caianiello”, Uńiversitá di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy); Albrow, M. D. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020 (New Zealand); Jung, Y. K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138 (United States); Collaboration: OGLE Collaboration; KMTNet Collaboration; and others

2016-08-10

In this paper, we demonstrate the severity of the degeneracy between the microlens-parallax and lens-orbital effects by presenting the analysis of the gravitational binary-lens event OGLE-2015-BLG-0768. Despite the obvious deviation from the model based on the linear observer motion and the static binary, it is found that the residual can be almost equally well explained by either the parallactic motion of the Earth or the rotation of the binary-lens axis, resulting in the severe degeneracy between the two effects. We show that the degeneracy can be readily resolved with the additional data provided by space-based microlens parallax observations. By enabling us to distinguish between the two higher-order effects, space-based microlens parallax observations will not only make it possible to accurately determine the physical lens parameters but also to further constrain the orbital parameters of binary lenses.

Breaking the EOS-gravity degeneracy with masses and pulsating frequencies of neutron stars

International Nuclear Information System (INIS)

Lin, Weikang; Li, Bao-An; Chen, Lie-Wen; Wen, De-Hua; Xu, Jun

2014-01-01

A thorough understanding of many astrophysical phenomena associated with compact objects requires reliable knowledge about both the equation of state (EOS) of super-dense nuclear matter and the theory of strong-field gravity simultaneously because of the EOS-gravity degeneracy. Currently, variations of the neutron star (NS) mass–radius correlation from using alternative gravity theories are much larger than those from changing the NS matter EOS within known constraints. At least two independent observables are required to break the EOS-gravity degeneracy. Using model EOSs for hybrid stars and a Yukawa-type non-Newtonian gravity, we investigate both the mass–radius correlation and pulsating frequencies of NSs. While the maximum mass of NSs increases, the frequencies of the f, p 1 , p 2 , and w I pulsating modes are found to decrease with the increasing strength of the Yukawa-type non-Newtonian gravity, providing a useful reference for future determination simultaneously of both the strong-field gravity and the supranuclear EOS by combining data of x-ray and gravitational wave emissions of NSs. (paper)

Proton stopping using a full conserving dielectric function in plasmas at any degeneracy

International Nuclear Information System (INIS)

Barriga-Carrasco, Manuel D.

2010-01-01

In this work, we present a dielectric function including the three conservation laws (density, momentum and energy) when we take into account electron-electron collisions in a plasma at any degeneracy. This full conserving dielectric function (FCDF) reproduces the random phase approximation (RPA) and Mermin ones, which confirms this outcome. The FCDF is applied to the determination of the proton stopping power. Differences among diverse dielectric functions in the proton stopping calculation are minimal if the plasma electron collision frequency is not high enough. These discrepancies can rise up to 2% between RPA values and the FCDF ones, and to 8% between the Mermin ones and FCDF ones. The similarity between RPA and FCDF results is not surprising, as all conservation laws are also considered in RPA dielectric function. Even for plasmas with low collision frequencies, those discrepancies follow the same behavior as for plasmas with higher frequencies. Then, discrepancies do not depend on the plasma degeneracy but essentially do on the value of the plasma collision frequency.

Weak linear degeneracy and lifespan of classical solutions for first order quasilinear hyperbolic systems

International Nuclear Information System (INIS)

Li Tatsien

1994-01-01

By means of the concept of the weak linear degeneracy, one gets the global existence and the sharp estimate of the lifespan of C 1 solutions to the Cauchy problem for general first order quasilinear hyperbolic systems with small initial data with compact support. (author). 23 refs, 1 fig

Open-System Quantum Annealing in Mean-Field Models with Exponential Degeneracy*

Directory of Open Access Journals (Sweden)

Kostyantyn Kechedzhi

2016-05-01

Full Text Available Real-life quantum computers are inevitably affected by intrinsic noise resulting in dissipative nonunitary dynamics realized by these devices. We consider an open-system quantum annealing algorithm optimized for such a realistic analog quantum device which takes advantage of noise-induced thermalization and relies on incoherent quantum tunneling at finite temperature. We theoretically analyze the performance of this algorithm considering a p-spin model that allows for a mean-field quasiclassical solution and, at the same time, demonstrates the first-order phase transition and exponential degeneracy of states, typical characteristics of spin glasses. We demonstrate that finite-temperature effects introduced by the noise are particularly important for the dynamics in the presence of the exponential degeneracy of metastable states. We determine the optimal regime of the open-system quantum annealing algorithm for this model and find that it can outperform simulated annealing in a range of parameters. Large-scale multiqubit quantum tunneling is instrumental for the quantum speedup in this model, which is possible because of the unusual nonmonotonous temperature dependence of the quantum-tunneling action in this model, where the most efficient transition rate corresponds to zero temperature. This model calculation is the first analytically tractable example where open-system quantum annealing algorithm outperforms simulated annealing, which can, in principle, be realized using an analog quantum computer.

Transversity Amplitudes in Hypercharge Exchange Processes

International Nuclear Information System (INIS)

Aguilar Benitez de Lugo, M.

1979-01-01

' In this work we present several techniques developed for the extraction of the. Transversity amplitudes governing quasi two-body meson baryon reactions with hypercharge exchange. We review the methods used in processes having a pure spin configuration, as well as the more relevant results obtained with data from K p and Tp interactions at intermediate energies. The predictions of the additive quark model and the ones following from exchange degeneracy and etoxicity are discussed. We present a formalism for amplitude analysis developed for reactions with mixed spin configurations and discuss the methods of parametric estimation of the moduli and phases of the amplitudes, as well as the various tests employed to check the goodness of the fits. The calculation of the generalized joint density matrices is given and we propose a method based on the generalization of the idea of multipole moments, which allows to investigate the structure of the decay angular correlations and establishes the quality of the fits and the validity of the simplifying assumptions currently used in this type of studies. (Author) 43 refs

Effects of neutrino degeneracy and of downscatter on neutrino radiation from dense stellar cores

International Nuclear Information System (INIS)

Lichtenstadt, I.; Ron, A.; Sack, N.; Wagschal, J.J.; Bludman, S.A.

1978-01-01

A simplified model is presneted for several stages in the development of a neutronization shell in the inner core of a collapsing star. Neutrino degeneracy severely reduces neutrino emission and downscatter in energy, so that for all but the thinest shell sources, surface emission of an approximately Fermi-Dirac neutrino spectrum obtains. The Neutrino spectrum departs from exact Fermi-Dirac neutrino form only because of the outstreaming of low-energy neutrinos.Downscatter by electrons is helped by neutron scatterers present, but except for reducing the peak neutrino energy by about 30%, electrons play no dramatic part. The neutrino degeneracy inhibits downscatter so that the low-energy window in the Fermi-Dirac distribution leads to little neutrino loss.A simple equilibrium radiation picture emerges in which neutrinos are LTE thermally emitted in the neutronization shell and isotropically coherently scattered by neutrons and by nuclei on the way out of the overlying mantle. The Fermi statistics limit on neutrino flux is probably reached in practice, but is, in most cases, still insufficient for mantle blow-off

Effects of target electron collisions on energy loss straggling in plasmas of all degeneracies

Energy Technology Data Exchange (ETDEWEB)

Barriga Carrasco, Manuel D. [E.T.S.I. Industriales, Universisdad de Castilla La Mancha, Ciudad Real E13071 (Spain)]. E-mail: ManuelD.Barriga@uclm.es

2007-07-01

The purpose of the present paper is to describe the effects of target electron collisions on the energy loss straggling in plasmas of any degeneracy. We focus our analysis on targets that are in the limit of weakly coupled electron gases, where the random phase approximation can be applied. This type of plasmas targets has not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtained from an exact quantum mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Also we consider electron collisions in the exact quantum mechanical straggling calculation. Now the maximum straggling occurs at velocities smaller than for the calculations without considering collisions for all kinds of plasmas analyzed. The straggling remains equal or enhances for velocities less than or equal to the velocity at maximum while is slightly decreases for higher velocities. Differences are significant in all cases, that can let large errors creep on in further energy deposition and projectile range studies.

Effects of target electron collisions on energy loss straggling in plasmas of all degeneracies

International Nuclear Information System (INIS)

Barriga Carrasco, Manuel D.

2007-01-01

The purpose of the present paper is to describe the effects of target electron collisions on the energy loss straggling in plasmas of any degeneracy. We focus our analysis on targets that are in the limit of weakly coupled electron gases, where the random phase approximation can be applied. This type of plasmas targets has not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtained from an exact quantum mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Also we consider electron collisions in the exact quantum mechanical straggling calculation. Now the maximum straggling occurs at velocities smaller than for the calculations without considering collisions for all kinds of plasmas analyzed. The straggling remains equal or enhances for velocities less than or equal to the velocity at maximum while is slightly decreases for higher velocities. Differences are significant in all cases, that can let large errors creep on in further energy deposition and projectile range studies

A general theorem on the transition probabilities of a quantum mechanical system with spatial degeneracy

NARCIS (Netherlands)

Tolhoek, H.A.; Groot, S.R. de

1949-01-01

In the general case of a quantum mechanical system with a Hamiltonian that is invariant for rotations spatial degeneracy will exist. So the initial state must be characterized except by the energy also by e.g. the magnetic quantum number. Both for emission of light and electrons plus neutrinos

On the AdS higher spin / O(N) vector model correspondence: degeneracy of the holographic image

International Nuclear Information System (INIS)

Diaz, Danilo E.; Dorn, Harald

2006-01-01

We explore the conjectured duality between the critical O(N) vector model and minimal bosonic massless higher spin (HS) theory in AdS. In the free boundary theory, the conformal partial wave expansion (CPWE) of the four-point function of the scalar singlet bilinear is reorganized to make it explicitly crossing-symmetric and closed in the singlet sector, dual to the bulk HS gauge fields. We are able to analytically establish the factorized form of the fusion coefficients as well as the two-point function coefficient of the HS currents. We insist in directly computing the free correlators from bulk graphs with the unconventional branch. The three-point function of the scalar bilinear turns out to be an 'extremal' one at d = 3. The four-point bulk exchange graph can be precisely related to the CPWs of the boundary dual scalar and its shadow. The flow in the IR by Legendre transforming at leading 1/N, following the pattern of double-trace deformations, and the assumption of degeneracy of the hologram lead to the CPWE of the scalar four-point function at IR. Here we confirm some previous results, obtained from more involved computations of skeleton graphs, as well as extend some of them from d = 3 to generic dimension 2 < d < 4

Vacuum degeneracy and Conformal Mass in Lovelock AdS gravity

Science.gov (United States)

Arenas-Henriquez, Gabriel; Miskovic, Olivera; Olea, Rodrigo

2017-11-01

It is shown that the notion of Conformal Mass can be defined within a given anti-de Sitter (AdS) branch of a Lovelock gravity theory as long as the corresponding vacuum is not degenerate. Indeed, conserved charges obtained by the addition of Kounterterms to the bulk action turn out to be proportional to the electric part of the Weyl tensor, when the fall-off of a generic solution in that AdS branch is considered. The factor of proportionality is the degeneracy condition for the vacua in the particular Lovelock AdS theory under study. This last feature explains the obstruction to define Conformal Mass in the degenerate case.

Influence of damping on proton energy loss in plasmas of all degeneracies

International Nuclear Information System (INIS)

Barriga-Carrasco, Manuel D.

2007-01-01

The purpose of the present paper is to describe the effects of electron-electron collisions on the stopping power of plasmas of any degeneracy. Plasma targets are considered fully ionized so electronic stopping is only due to the free electrons. We focus our analysis on plasmas which electronic density is around solid values n e ≅10 23 cm -3 and which temperature is around T≅10 eV; these plasmas are in the limit of weakly coupled plasmas. This type of plasma has not been studied extensively though it is very important for inertial confinement fusion. The electronic stopping is obtained from an exact quantum mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Differences are around 30% in some cases which can produce bigger mistakes in further energy deposition and projectile range studies. Then we consider electron-electron collisions in the exact quantum mechanical electronic stopping calculation. Now the maximum stopping occurs at velocities smaller than for the calculations without considering collisions for all kinds of plasmas analyzed. The energy loss enhances for velocities smaller than the velocity at maximum while decreases for higher velocities. Latter effects are magnified with increasing collision frequency. Differences with the same results for the case of not taking into account collisions are around 20% in the analyzed cases

SPITZER OBSERVATIONS OF OGLE-2015-BLG-1212 REVEAL A NEW PATH TOWARD BREAKING STRONG MICROLENS DEGENERACIES

DEFF Research Database (Denmark)

Bozza, V.; Shvartzvald, Y.; Udalski, A.

2016-01-01

Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter s...

Lifting degeneracies in Higgs couplings using single top production in association with a Higgs boson

CERN Document Server

Farina, Marco; Maltoni, Fabio; Salvioni, Ennio; Thamm, Andrea

2013-01-01

Current Higgs data show an ambiguity in the value of the Yukawa couplings to quarks and leptons. Not so much because of still large uncertainties in the measurements but as the result of several almost degenerate minima in the coupling profile likelihood function. To break these degeneracies, it is important to identify and measure processes where the Higgs coupling to fermions interferes with other coupling(s). The most prominent example, the decay of $h \\to \\gamma \\gamma$, is not sufficient to give a definitive answer. In this Letter, we argue that $t$-channel single top production in association with a Higgs boson, with $h\\to b\\bar b$, can provide the necessary information to lift the remaining degeneracy in the top Yukawa. Within the Standard Model, the total rate is highly reduced due to an almost perfect destructive interference in the hard process, $W b \\rightarrow t h$. We first show that for non-standard couplings the cross section can be reliably computed without worrying about corrections from phys...

Fermi-degeneracy and discrete-ion effects in the spherical-cell model and electron-electron correlation effects in hot dense plasmas

International Nuclear Information System (INIS)

Furukawa, H.; Nishihara, K.

1992-01-01

The spherical-cell model [F. Perrot, Phys. Rev. A 25, 489 (1982); M. W. C. Dharma-wardana and F. Perrot, ibid. 26, 2096 (1982)] is improved to investigate laser-produced hot, dense plasmas. The free-electron distribution function around a test free electron is calculated by using the Fermi integral in order that the free-electron--free-electron correlation function includes Fermi-degeneracy effects, and also that the calculation includes the discrete-ion effect. The free-electron--free-electron, free-electron--ion, and ion-ion correlation effects are coupled, within the framework of the hypernetted-chain approximation, through the Ornstein-Zernike relation. The effective ion-ion potential includes the effect of a spatial distribution of bound electrons. The interparticle correlation functions and the effective potential acting on either an electron or an ion in hot, dense plasmas are calculated numerically. The Fermi-degeneracy effect on the correlation functions between free electrons becomes clear for the degeneracy parameter θ approx-lt 1. The discrete-ion effect in the calculation of the correlation functions between free electrons affects the electron-ion pair distribution functions for r s approx-gt 3. As an application of the proposed model, the strong-coupling effect on the stopping power of charged particles [Xin-Zhong Yan, S. Tanaka, S. Mitake, and S. Ichimaru, Phys. Rev. A 32, 1785 (1985)] is estimated. While the free-electron--ion strong-coupling effect and the Fermi-degeneracy effect incorporated in the calculation of the free-electron distribution function around a test free electron enhance the stopping number, the quantum-diffraction effect incorporated in the quantal hypernetted-chain equations [J. Chihara, Prog. Theor. Phys. 72, 940 (1984); Phys. Rev. A 44, 1247 (1991); J. Phys. Condens. Matter 3, 8715 (1991)] reduces the stopping number substantially

Degeneracy of time series models: The best model is not always the correct model

International Nuclear Information System (INIS)

Judd, Kevin; Nakamura, Tomomichi

2006-01-01

There are a number of good techniques for finding, in some sense, the best model of a deterministic system given a time series of observations. We examine a problem called model degeneracy, which has the consequence that even when a perfect model of a system exists, one does not find it using the best techniques currently available. The problem is illustrated using global polynomial models and the theory of Groebner bases

Interpretación de los precios sombra en presencia de degeneración

OpenAIRE

León, T.; Liern, V.

1996-01-01

El propósito de nuestro trabajo es analizar la interpretación económica de las variables duales como "precios sombra" cuando la solución posible básica óptima del problema de programación lineal es degenerada. Resolvemos algunos ejemplos que ilustran esta interpretación usando el programa LINDO. Finalmente planteamos una modificación a la propuesta de Gal (1986) para llevar a cabo el análisis de sensibilidad en presencia de degeneración.

La importancia de la dieta en la degeneración macular asociada a la edad y su relación con el pigmento macular

OpenAIRE

Delgado Melendro, Carlos

2014-01-01

La Degeneración macular asociada a la edad (DMAE), se define como una enfermedad degenerativa que cursa con alteraciones del epitelio pigmentario de la retina (EPR), la membrana de Bruch y la coriocapilaris. Las anomalías en el EPR provoca una degeneración del mismo y de los fotoreceptores de la retina central o área macular causando una pérdida de la visión central irreversible (Chen et al., 2010). La etapa inicial de la enfermedad se caracteriza por la presencia de drusas constituidas po...

Non-degeneracy, Mean Field Equations and the Onsager Theory of 2D Turbulence

Science.gov (United States)

Bartolucci, Daniele; Jevnikar, Aleks; Lee, Youngae; Yang, Wen

2018-04-01

The understanding of some large energy, negative specific heat states in the Onsager description of 2D turbulence seem to require the analysis of a subtle open problem about bubbling solutions of the mean field equation. Motivated by this application we prove that, under suitable non-degeneracy assumptions on the associated m-vortex Hamiltonian, the m-point bubbling solutions of the mean field equation are non-degenerate as well. Then we deduce that the Onsager mean field equilibrium entropy is smooth and strictly convex in the high energy regime on domains of second kind.

Microlensing and Its Degeneracy Breakers: Parallax, Finite Source, High-Resolution Imaging, and Astrometry

Directory of Open Access Journals (Sweden)

Chien-Hsiu Lee

2017-07-01

Full Text Available First proposed by Paczynski in 1986, microlensing has been instrumental in the search for compact dark matter as well as discovery and characterization of exoplanets. In this article, we provide a brief history of microlensing, especially on the discoveries of compact objects and exoplanets. We then review the basics of microlensing and how astrometry can help break the degeneracy, providing a more robust determination of the nature of the microlensing events. We also outline prospects that will be made by on-going and forth-coming experiments/observatories.

Breaking a dark degeneracy with gravitational waves

Energy Technology Data Exchange (ETDEWEB)

Lombriser, Lucas; Taylor, Andy, E-mail: llo@roe.ac.uk, E-mail: ant@roe.ac.uk [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

2016-03-01

We identify a scalar-tensor model embedded in the Horndeski action whose cosmological background and linear scalar fluctuations are degenerate with the concordance cosmology. The model admits a self-accelerated background expansion at late times that is stable against perturbations with a sound speed attributed to the new field that is equal to the speed of light. While degenerate in scalar fluctuations, self-acceleration of the model implies a present cosmological tensor mode propagation at ∼<95 % of the speed of light with a damping of the wave amplitude that is ∼>5 % less efficient than in general relativity. We show that these discrepancies are endemic to self-accelerated Horndeski theories with degenerate large-scale structure and are tested with measurements of gravitational waves emitted by events at cosmological distances. Hence, gravitational-wave cosmology breaks the dark degeneracy in observations of the large-scale structure between two fundamentally different explanations of cosmic acceleration—a cosmological constant and a scalar-tensor modification of gravity. The gravitational wave event GW150914 recently detected with the aLIGO instruments and its potential association with a weak short gamma-ray burst observed with the Fermi GBM experiment may have provided this crucial measurement.

On the ground-state degeneracy and entropy in a double-tetrahedral chain formed by the localized Ising spins and mobile electrons

Science.gov (United States)

Gálisová, Lucia

2018-05-01

Ground-state properties of a hybrid double-tetrahedral chain, in which the localized Ising spins regularly alternate with triangular plaquettes occupied by a variable number of mobile electrons, are exactly investigated. We demonstrate that the zero-temperature phase diagram of the model involves several non-degenerate, two-fold degenerate and macroscopically degenerate chiral phases. Low-temperature dependencies of the entropy and specific heat are also examined in order to gain a deeper insight into the degeneracy of individual ground-state phases and phase transitions. It is shown that a diversity of the ground-state degeneracy manifests itself in multiple-peak structures of both thermodynamic quantities. A remarkable temperature dependencies of the specific heat with two and three Schottky-type maxima are discussed in detail.

Effects of degeneracy and response function in a diffusion predator-prey model

Science.gov (United States)

Li, Shanbing; Wu, Jianhua; Dong, Yaying

2018-04-01

In this paper, we consider positive solutions of a diffusion predator-prey model with a degeneracy under the Dirichlet boundary conditions. We first obtain sufficient conditions of the existence of positive solutions by the Leray-Schauder degree theory, and then analyze the limiting behavior of positive solutions as the growth rate of the predator goes to infinity and the conversion rates of the predator goes to zero, respectively. It is shown that these results for Holling II response function (i.e. m  >  0) reveal interesting contrast with that for the classical Lotka-Volterra predator-prey model (i.e. m  =  0).

Kramers degeneracy and relaxation in vanadium, niobium and tantalum clusters

Science.gov (United States)

Diaz-Bachs, A.; Katsnelson, M. I.; Kirilyuk, A.

2018-04-01

In this work we use magnetic deflection of V, Nb, and Ta atomic clusters to measure their magnetic moments. While only a few of the clusters show weak magnetism, all odd-numbered clusters deflect due to the presence of a single unpaired electron. Surprisingly, for the majority of V and Nb clusters an atomic-like behavior is found, which is a direct indication of the absence of spin–lattice interaction. This is in agreement with Kramers degeneracy theorem for systems with a half-integer spin. This purely quantum phenomenon is surprisingly observed for large systems of more than 20 atoms, and also indicates various quantum relaxation processes, via Raman two-phonon and Orbach high-spin mechanisms. In heavier, Ta clusters, the relaxation is always present, probably due to larger masses and thus lower phonon energies, as well as increased spin–orbit coupling.

Coupling of reciprocal vectors and corresponding degeneracy effect in a dual-periodic optical superlattice

International Nuclear Information System (INIS)

Qin Yiqiang

2006-01-01

A dual-periodic structure for quasi-phase matching cascaded optical parametric interactions is proposed. Due to the coupling of reciprocal vectors between the original and imposed periodic sequence, the reciprocal vectors and the corresponding effective nonlinear coefficients is no longer the simple combination of two periodic structures. The new analytical expression of the effective nonlinear coefficients is deduced and given. The degeneracy phenomena and the novel extinction rule resulting from the coupling of reciprocal vectors are found and investigated. The corresponding physical nature is also discussed

Algebraic quantization of systems with a gauge degeneracy

International Nuclear Information System (INIS)

Grundling, H.B.G.S.; Hurst, C.A.

1985-01-01

Systems with a gauge degeneracy are characterized either by supplementary conditions, or by a set of generators of gauge transformations, or by a set of constraints deriving from Dirac's canonical constraint method. These constraints can be expressed either as conditions on the field algebra F, or on the states on F. In a Csup(*)-algebra framework, we show that the state conditions give rise to a factor algebra of a subalgebra of the field algebra F. This factor algebra R, is free of state conditions. In this formulation we show also that the algebraic conditions can be treated in the same way as the state conditions. The connection between states on F and states on R is investigated further within this framework, as is also the set of transformations which are compatible with the set of constraints. It is also shown that not every set of constraints can give rise to a nontrivial system. Finally as an example, the abstract theory is applied to the electromagnetic field, and this treatment can be generalized to all systems of bosons with linear constraints. The question of dynamics is not discussed. (orig.)

Degeneracy breakdown as a source of supernovae Ia

Science.gov (United States)

Clavelli, L.

2018-01-01

In a confined system of multiple Fermions, the particles are forced into high energy levels by the Pauli Exclusion Principle. We refer to this system as a Pauli tower. We pursue the investigation of a model for sub-Chandrasekhar supernovae Ia explosions (SNIa) in which the energy stored in the Pauli tower is released to trigger a nuclear deflagration. The simplest physical model for such a degeneracy breakdown and collapse of the Pauli tower is a phase transition to an exactly supersymmetric state in which the scalar partners of protons, neutrons, and leptons become degenerate with the familiar fermions of our world as in the supersymmetric standard model with susy breaking parameters relaxed to zero. We focus on the ability of the susy phase transition model to fit the total SNIa rate as well as the delay time distribution of SNIa after the birth of a progenitor white dwarf. We also study the ejected mass distribution and its correlation with delay time. Finally, we discuss the expected SNIa remnant in the form of a black hole of roughly Jupiter mass and the prospects for detecting such remnants.

Logarithmic Exchange Kinetics in Monodisperse Copolymeric Micelles

Science.gov (United States)

García Daza, Fabián A.; Bonet Avalos, Josep; Mackie, Allan D.

2017-06-01

Experimental measurements of the relaxation kinetics of copolymeric surfactant exchange for micellar systems unexpectedly show a peculiar logarithmic decay. Several authors use polydispersity as an explanation for this behavior. However, in coarse-grained simulations that preserve microscopic details of the surfactants, we find evidence of the same logarithmic behavior. Since we use a strictly monodisperse distribution of chain lengths such a relaxation process cannot be attributed to polydispersity, but has to be caused by an inherent physical process characteristic of this type of system. This is supported by the fact that the decay is specifically logarithmic and not a power law with an exponent inherited from the particular polydispersity distribution of the sample. We suggest that the degeneracy of the energy states of the hydrophobic block in the core, which is broken on leaving the micelle, can qualitatively explain the broad distribution of energy barriers, which gives rise to the observed nonexponential relaxation.

Near-degeneracy in Excited Vibrational States of 207PbF

Science.gov (United States)

Mawhorter, Richard; Nguyen, Alexander; Kim, Yongrak; Biekert, Andreas; Sears, Trevor; Grabow, Jens-Uwe; Kudashov, A. D.; Skripnikov, L. V.; Titov, A. V.; Petrov, A. N.

2017-04-01

High-resolution Fourier transform microwave (FTMW) spectroscopy studies of 207PbF have demonstrated the near-degeneracy of two levels of opposite parity. These have attracted attention for the study of parity violation effects and the variation of fundamental constants using 207PbF. Further theoretical work has improved our detailed understanding of both 207PbF and 208PbF, and furthermore recently indicated that the finely split +/- parity levels grow monotonically closer for higher vibrational states. Our experimental results for v = 0-3 confirm this, and are in excellent agreement with our extended theoretical calculations up to v = 4; both will be presented. TJS acknowledges support from Contract No. DE-SC0012704 with the U.S. Department of Energy, Office of Science, supported by its Division of Chemical Sciences, Geosciences and Biosciences within the Office of Basic Energy Sciences., as do RM, AB, YK, & AN from Pomona College & J-UG from the Deutsche Forschungsgemeinschaft (DFG).

Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field.

Science.gov (United States)

Zhao, Chuan; Norden, Tenzin; Zhang, Peiyao; Zhao, Puqin; Cheng, Yingchun; Sun, Fan; Parry, James P; Taheri, Payam; Wang, Jieqiong; Yang, Yihang; Scrace, Thomas; Kang, Kaifei; Yang, Sen; Miao, Guo-Xing; Sabirianov, Renat; Kioseoglou, George; Huang, Wei; Petrou, Athos; Zeng, Hao

2017-08-01

Exploiting the valley degree of freedom to store and manipulate information provides a novel paradigm for future electronics. A monolayer transition-metal dichalcogenide (TMDC) with a broken inversion symmetry possesses two degenerate yet inequivalent valleys, which offers unique opportunities for valley control through the helicity of light. Lifting the valley degeneracy by Zeeman splitting has been demonstrated recently, which may enable valley control by a magnetic field. However, the realized valley splitting is modest (∼0.2 meV T -1 ). Here we show greatly enhanced valley spitting in monolayer WSe 2 , utilizing the interfacial magnetic exchange field (MEF) from a ferromagnetic EuS substrate. A valley splitting of 2.5 meV is demonstrated at 1 T by magnetoreflectance measurements and corresponds to an effective exchange field of ∼12 T. Moreover, the splitting follows the magnetization of EuS, a hallmark of the MEF. Utilizing the MEF of a magnetic insulator can induce magnetic order and valley and spin polarization in TMDCs, which may enable valleytronic and quantum-computing applications.

SU(2) symmetry and degeneracy from SUSY QM of a neutron in the magnetic field of a linear current

International Nuclear Information System (INIS)

Martinez, D.; Granados, V.D.; Mota, R.D.

2006-01-01

From SUSY ladder operators in momentum space of a neutron in the magnetic field of a linear current, we construct 2x2 matrix operators that together with the z-component of the total angular momentum satisfy the su(2) Lie algebra. We use this fact to explain the degeneracy of the energy spectrum

Investigating the large degeneracy Kondo lattice metamagnet CeTiGe: Crystal growth and doping studies

Energy Technology Data Exchange (ETDEWEB)

Gruner, T.; Caroca-Canales, N.; Deppe, M.; Geibel, C. [MPI fuer Chemische Physik fester Stoffe, 01187, Dresden (Germany); Sereni, J. [Centro Atomico Bariloche, 8400, S. C. de Bariloche (Argentina)

2011-07-01

CeTiGe is a paramagnetic Kondo lattice system with a large orbital degeneracy involved in the formation of the heavy Fermion ground state. Recently we discovered that this compound presents a huge metamagnetic transition at B{sub MMT} {approx} 13 T, with much larger anomalies in magnetization, magnetoresistance and magnetostriction than in the archetypical Kondo lattice metamagnet CeRu{sub 2}Si{sub 2}. Since CeTiGe forms in a pronounced peritectic reaction the growth of single crystals is difficult. We therefore studied the Ce-Ti-Ge ternary metallographic phase diagram to get a sound basis for future crystal growth attempts. Preliminary results of growth experiments based on these studies are promising and shall be discussed. Furthermore, Ti-rich CeTiGe was recently reported to present a high temperature phase crystallizing in the closely related CeScSi structure type. In order to study this structural instability and the effect on the physical properties, we studied the effect of substituting Sc for Ti, since pure CeScGe crystallizes in the CeScSi structure type. In well annealed samples we observed a two phase region in the range 10% - 25%-Sc-substitution. Preliminary investigations of the CeSc{sub x}Ti{sub 1-x}Ge alloy suggest it is a promising candidate for the observation of a ferromagnetic quantum critical point in a large degeneracy Kondo lattice system.

Modelos animales de degeneración cognitiva y uso de transplantes neurales de células madre como terapia

Directory of Open Access Journals (Sweden)

Alcyr Alves de Oliveira

2017-02-01

Full Text Available Existen pocos modelos animales de degeneración cognitiva que podrían ser considerados tan importantes como el modelo de lesión colinérgica de la enfermedad de Alzheimer. La enfermedad de Alzheimer es una patología neurodegenerativa asociada con el envejecimiento y con degeneración cognitiva acentuada y progresiva. Sus complejas y múltiples vías neurales secuenciales pueden conducir a la comprensión de que las intervenciones de agente único pueden ser insuficiente para impactar el curso de esta enfermedad. El tratamiento farmacológico actual es paliativo y, aunque pueda retardar el progreso de la enfermedad, no es capaz de ofrecer una cura. La combinación de drogas y sustancias antioxidantes han sido investigadas, sin embargo, existen pocos estudios que demuestran resultados consistentes basados en esta presunción. Así, el objetivo de este artículo fue destacar las terapias basadas en la reposición celular como potencial tratamiento para enfermedades del sistema nervioso periférico y central.

Massive boson-fermion degeneracy and the early structure of the universe

International Nuclear Information System (INIS)

Kounnas, C.

2008-01-01

The existence of a new kind of massive boson-fermion symmetry is shown explicitly in the framework of the heterotic, type II and type II orientifold superstring theories. The target space-time is two-dimensional. Higher dimensional models are defined via large marginal deformations of J anti J-type. The spectrum of the initial undeformed two dimensional vacuum consists of massless boson degrees of freedom, while all massive boson and fermion degrees of freedom exhibit a new Massive Spectrum Degeneracy Symmetry (MSDS). This precise property, distinguishes the MSDS theories from the well known supersymmetric SUSY-theories. Some proposals are stated in the framework of these theories concerning the structure of: (i) The Early Non-singular Phase of the Universe, (ii) The two dimensional boundary theory of AdS 3 Black-Holes, (iii) Plausible applications of the MSDS theories in particle physics, alternative to SUSY. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Measurement of exclusive hypercharge-exchange reactions at 35 to 140 GeV/c

International Nuclear Information System (INIS)

Arenton, M. W.; Ayres, D.S.; Cohen, D.

1978-07-01

Data on the reactions π + p → K + Σ + and π + p → K + Y* + were obtained using the Fermilab Single Arm Spectrometer Facility at incident π + momenta of 35, 70, and 140 GeV/c for momentum transfers vertical bar t vertical bar less than or approximately equal to 1 GeV 2 . The line-reversed reactions K - p → π - Σ + and K - p → π - Y* + were also studied at 70 GeV/c with the same apparatus in order to test exchange degeneracy of the K*(890) and K**(1420) trajectories. Preliminary results on the first set of reactions at 70 GeV/c are presented and found to be in qualitative agreement with the model of Navelet and Stevens

Degeneracy-driven self-structuring dynamics in selective repertoires.

Science.gov (United States)

Atamas, Sergei P; Bell, Jonathan

2009-08-01

Numerous biological interactions, such as interactions between T cell receptors or antibodies with antigens, interactions between enzymes and substrates, or interactions between predators and prey are often not strictly specific. In such less specific, or "sloppy," systems, referred to here as degenerate systems, a given unit of a diverse resource (antigens, enzymatic substrates, prey) is at risk of being recognized and consumed by multiple consumers (lymphocytes, enzymes, predators). In this study, we model generalized degenerate consumer-resource systems of Lotka-Volterra and Verhulst types. In the degenerate systems of Lotka-Volterra, there is a continuum of types of consumer and resource based on variation of a single trait (characteristic, or preference). The consumers experience competition for a continuum of resource types. This non-local interaction system is modeled with partial differential-integral equations and shows spontaneous self-structuring of the consumer population that depends on the degree of interaction degeneracy between resource and consumer, but does not mirror the distribution of resource. We also show that the classical Verhulst (i.e. logistic) single population model can be generalized to a degenerate model, which shows qualitative behavior similar to that in the degenerate Lotka-Volterra model. These results provide better insight into the dynamics of selective systems in biology, suggesting that adaptation of degenerate repertoires is not a simple "mirroring" of the environment by the "fittest" elements of population.

Internal parity symmetry and degeneracy of Bethe Ansatz strings in the isotropic heptagonal magnetic ring

Energy Technology Data Exchange (ETDEWEB)

Milewski, J., E-mail: jsmilew@wp.pl [Institute of Mathematics, Poznań University of Technology, Piotrowo 3A, 60-965 Poznań (Poland); Lulek, B., E-mail: barlulek@amu.edu.pl [East European State Higher School, ul. Tymona Terleckiego 6, 37-700 Przemyśl (Poland); Lulek, T., E-mail: tadlulek@prz.edu.pl [Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); East European State Higher School, ul. Tymona Terleckiego 6, 37-700 Przemyśl (Poland); Łabuz, M., E-mail: labuz@univ.rzeszow.pl [University of Rzeszow, Institute of Physics, Rejtana 16a, 35-959 Rzeszów (Poland); Stagraczyński, R., E-mail: rstag@prz.edu.pl [Rzeszow University of Technology, The Faculty of Mathematics and Applied Physics, Powstańców Warszawy 6, 35-959 Rzeszów (Poland)

2014-02-01

The exact Bethe eigenfunctions for the heptagonal ring within the isotropic XXX model exhibit a doubly degenerated energy level in the three-deviation sector at the centre of the Brillouin zone. We demonstrate an explicit construction of these eigenfunctions by use of algebraic Bethe Ansatz, and point out a relation of degeneracy to parity conservation, applied to the configuration of strings for these eigenfunctions. Namely, the internal structure of the eigenfunctions (the 2-string and the 1-string, with opposite quasimomenta) admits generation of two mutually orthogonal eigenfunctions due to the fact that the strings which differ by their length are distinguishable objects.

Long lifetime and high-fidelity quantum memory of photonic polarization qubit by lifting zeeman degeneracy.

Science.gov (United States)

Xu, Zhongxiao; Wu, Yuelong; Tian, Long; Chen, Lirong; Zhang, Zhiying; Yan, Zhihui; Li, Shujing; Wang, Hai; Xie, Changde; Peng, Kunchi

2013-12-13

Long-lived and high-fidelity memory for a photonic polarization qubit (PPQ) is crucial for constructing quantum networks. We present a millisecond storage system based on electromagnetically induced transparency, in which a moderate magnetic field is applied on a cold-atom cloud to lift Zeeman degeneracy and, thus, the PPQ states are stored as two magnetic-field-insensitive spin waves. Especially, the influence of magnetic-field-sensitive spin waves on the storage performances is almost totally avoided. The measured average fidelities of the polarization states are 98.6% at 200  μs and 78.4% at 4.5 ms, respectively.

Target electron collision effects on energy loss straggling of protons in an electron gas at any degeneracy

International Nuclear Information System (INIS)

Barriga-Carrasco, Manuel D.

2008-01-01

The purpose of the present paper is to describe the effects of target electron collisions on proton energy loss straggling in plasmas at any degeneracy. Targets are considered fully ionized so electronic energy loss is only due to the free electrons. The analysis is focused on targets with electronic density around solid values n e ≅10 23 cm -3 and with temperature around T≅10 eV; these targets are in the limit of weakly coupled electron gases. These types of plasma targets have not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtained from an exact quantum-mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Then electron collisions in the exact quantum-mechanical straggling calculation are considered. Now the energy loss straggling is enhanced for energies smaller than the energy before the maximum, then decreases around this maximum, and finally tends to the same values with respect to noncollisional calculation. Differences with the same results but not taking into account these collisions are as far as 17% in the cases analyzed. As an example, proton range distributions have been calculated to show the importance of an accurate energy straggling calculation

A family-universal anomalous U(1) in string models as the origin of supersymmetry breaking and squark degeneracy

International Nuclear Information System (INIS)

Faraggi, A.E.; Pati, J.C.

1997-12-01

Recently a promising mechanism for supersymmetry breaking that utilizes both an anomalous U(1) gauge symmetry and an effective mass term m ∼ 1TeV of certain relevant fields has been proposed. In this paper we examine whether such a mechanism can emerge in superstring derived free fermionic models. We observe that certain three generation string solutions, though not all, lead to an anomalous U(1) which couples universally to all three families. The advantages of this three-family universality of U(1) A , compared to the two-family case, proposed in earlier works, in yielding squark degeneracy, while avoiding radiative breaking of color and charge, are noted. The root cause of the flavor universality of U(1) A is the cyclic permutation symmetry that characterizes the Z 2 x Z 2 orbifold compactification with standard embedding, realized in the free fermionic models by the NAHE set. It is shown that nonrenormalizable terms which contain hidden-sector condensates, generate the required suppression of the relevant mass term m, compared to the Planck scale. While the D-term of the family universal U(1) A leads to squark degeneracy, those of the family dependent U(1)'s, remarkably enough, are found to vanish for the solutions considered, owing to minimization of the potential

Spoken language achieves robustness and evolvability by exploiting degeneracy and neutrality.

Science.gov (United States)

Winter, Bodo

2014-10-01

As with biological systems, spoken languages are strikingly robust against perturbations. This paper shows that languages achieve robustness in a way that is highly similar to many biological systems. For example, speech sounds are encoded via multiple acoustically diverse, temporally distributed and functionally redundant cues, characteristics that bear similarities to what biologists call "degeneracy". Speech is furthermore adequately characterized by neutrality, with many different tongue configurations leading to similar acoustic outputs, and different acoustic variants understood as the same by recipients. This highlights the presence of a large neutral network of acoustic neighbors for every speech sound. Such neutrality ensures that a steady backdrop of variation can be maintained without impeding communication, assuring that there is "fodder" for subsequent evolution. Thus, studying linguistic robustness is not only important for understanding how linguistic systems maintain their functioning upon the background of noise, but also for understanding the preconditions for language evolution. © 2014 WILEY Periodicals, Inc.

Dispersion characteristics of anisotropic unmagnetized ultra-relativistic transverse plasma wave with arbitrary electron degeneracy

Science.gov (United States)

Sarfraz, M.; Farooq, H.; Abbas, G.; Noureen, S.; Iqbal, Z.; Rasheed, A.

2018-03-01

Thermal momentum space anisotropy is ubiquitous in many astrophysical and laboratory plasma environments. Using Vlasov-Maxwell's model equations, a generalized polarization tensor for a collisionless ultra-relativistic unmagnetized electron plasma is derived. In particular, the tensor is obtained by considering anisotropy in the momentum space. The integral of moments of Fermi-Dirac distribution function in terms of Polylog functions is used for describing the border line plasma systems (T/e TF e ≈1 ) comprising arbitrary electron degeneracy, where Te and TF e, are thermal and Fermi temperatures, respectively. Furthermore, the effects of variation in thermal momentum space anisotropy on the electron equilibrium number density and the spectrum of electromagnetic waves are analyzed.

Transversity Amplitudes in Hypercharge Exchange Processes; Amplitudes de transversidad en procesos de intercambio de hipercarga

Energy Technology Data Exchange (ETDEWEB)

Aguilar Benitez de Lugo, M.

1979-07-01

In this work we present several techniques developed for the extraction of the. Transversity amplitudes governing quasi two-body meson baryon reactions with hypercharge exchange. We review the methods used In processes having a pure spin configuration, as well as the more relevant results obtained with data from K{sup p} and Tp interactions at intermediate energies. The predictions of the additive quark model and the ones following from exchange degeneracy and etoxicity are discussed. We present a formalism for amplitude analysis developed for reactions with mixed spin configurations and discuss the methods of parametric estimation of the moduli and phases of.the amplitudes, as well as the various tests employed to check the goodness of the fits. The calculation of the generalized joint density matrices is given and we propose a method based on the generalization of the idea of multipole moments, which allows to investigate the structure of the decay angular correlations and establishes the quality of the fits and the validity of the simplifying assumptions currently used in this type of studies. (Author) 43 refs.

Emil Kraepelin y el problema de la degeneración Emil Kraepelin and the problem of degeneration

Directory of Open Access Journals (Sweden)

Sandra Caponi

2010-12-01

Full Text Available Al mismo tiempo que Kraepelin estableció las bases de lo que hoy entendemos por psiquiatría, mantuvo la ambición de los higienistas del siglo XIX de pensar los problemas sociales con categorías médicas. Privilegiando el texto que Kraepelin dedica a la degeneración, se analizan las deudas entre la metodología de investigación de enfermedades psiquiátricas por él iniciada y la teoría de la degeneración de Morel. Se analiza la preocupación de Kraepelin por establecer una clasificación de las patologías mentales tan bien fundada como las clasificaciones de patologías biológicas, el uso de las estadísticas comparativas y las explicaciones dadas a la herencia mórbida.When Kraepelin laid the foundations of what we now understand as psychiatry, he was faithful to the nineteenth-century hygienist's penchant for approaching social problems in terms of medical categories. With Kraepelin's writings on the issue of degeneration as a backdrop, the article analyzes how the methodology he introduced for researching psychiatric illnesses is indebted to Morel's theory of degeneration. The article explores not only Kraepelin's concern with defining a classification of mental pathologies just as well grounded as the classifications of biological pathologies, but also his use of comparative statistics and his explanations of morbid heredity.

Marginal deformations of vacua with massive boson-fermion degeneracy symmetry

International Nuclear Information System (INIS)

Florakis, Ioannis; Kounnas, Costas; Toumbas, Nicolaos

2010-01-01

Two-dimensional string vacua with Massive Spectrum boson-fermion Degeneracy Symmetry, [MSDS] d=2 , are explicitly constructed in Type II and Heterotic superstring theories. The study of their moduli space indicates the existence of large marginal deformations that connect continuously the initial [MSDS] d=2 vacua to higher-dimensional conventional superstring vacua, where spacetime supersymmetry is spontaneously broken by geometrical fluxes. We find that the maximally symmetric, [Max:MSDS] d=2 , Type II vacuum, is in correspondence with the maximal, N=8, d=4 'gauged supergravity', where the supergravity gauging is induced by the fluxes. This correspondence is extended to less symmetric cases where the initial MSDS symmetry is reduced by orbifolds: [Z orb :MSDS] d=2 ↔[N≤8:SUGRA] d=4,fluxes . We also exhibit and analyse thermal interpretations of some Euclidean versions of the models and identify classes of MSDS vacua that remain tachyon-free under arbitrary marginal deformations about the extended symmetry point. The connection between the two-dimensional MSDS vacua and the resulting four-dimensional effective supergravities arises naturally within the context of an adiabatic cosmological evolution, where the very early Universe is conjectured to be described by an MSDS vacuum, while at late cosmological times it is described by an effective N=1 supergravity theory with spontaneously broken supersymmetry.

Análisis de la degeneración de los fotorreceptoes en modelos experimentales de retinosis pigmentaria, degeneración macular asociada a la edad y glaucoma =Analysis of photoreceptor degeneration in experimental models of retinitis pigmentosa, aging macular degeneration and glaucoma

OpenAIRE

Ortín Martínez, Arturo

2015-01-01

. Objetivo. Determinar el número total y la topografía de la población de conos en roedores adultos utilizando rutinas automatizadas que nos permita investigar objetivamente los efectos de diferentes modelos experimentales de patologías humanas tales como la degeneración macular asociada a la edad (DMAE), retinosis pigmentaria (RP) y la neuropatía óptica glaucomatosa (NOG) sobre la población de fotorreceptores. Material y métodos. Se han utilizado cinco cepas distinta de roedor...

Análisis de la degeneración de los fotorreceptoes en modelos experimentales de retinosis pigmentaria, degeneración macular asociada a la edad y glaucoma =Analysis of photoreceptor degeneration in experimental models of retinitis pigmentosa, aging macular degeneration and glaucoma

OpenAIRE

Ortín Martínez, Arturo

2015-01-01

Objetivo. Determinar el número total y la topografía de la población de conos en roedores adultos utilizando rutinas automatizadas que nos permita investigar objetivamente los efectos de diferentes modelos experimentales de patologías humanas tales como la degeneración macular asociada a la edad (DMAE), retinosis pigmentaria (RP) y la neuropatía óptica glaucomatosa (NOG) sobre la población de fotorreceptores. Material y métodos. Se han utilizado cinco cepas distinta de roedores: Sprague-Dawle...

Convenient method for resolving degeneracies due to symmetry of the magnetic susceptibility tensor and its application to pseudo contact shift-based protein-protein complex structure determination

Energy Technology Data Exchange (ETDEWEB)

Kobashigawa, Yoshihiro; Saio, Tomohide [Hokkaido University, Department of Structural Biology, Faculty of Advanced Life Science (Japan); Ushio, Masahiro [Hokkaido University, Graduate School of Life Science (Japan); Sekiguchi, Mitsuhiro [Astellas Pharma Inc., Analysis and Pharmacokinetics Research Labs, Department of Drug Discovery (Japan); Yokochi, Masashi; Ogura, Kenji; Inagaki, Fuyuhiko, E-mail: finagaki@pharm.hokudai.ac.jp [Hokkaido University, Department of Structural Biology, Faculty of Advanced Life Science (Japan)

2012-05-15

Pseudo contact shifts (PCSs) induced by paramagnetic lanthanide ions fixed in a protein frame provide long-range distance and angular information, and are valuable for the structure determination of protein-protein and protein-ligand complexes. We have been developing a lanthanide-binding peptide tag (hereafter LBT) anchored at two points via a peptide bond and a disulfide bond to the target proteins. However, the magnetic susceptibility tensor displays symmetry, which can cause multiple degenerated solutions in a structure calculation based solely on PCSs. Here we show a convenient method for resolving this degeneracy by changing the spacer length between the LBT and target protein. We applied this approach to PCS-based rigid body docking between the FKBP12-rapamycin complex and the mTOR FRB domain, and demonstrated that degeneracy could be resolved using the PCS restraints obtained from two-point anchored LBT with two different spacer lengths. The present strategy will markedly increase the usefulness of two-point anchored LBT for protein complex structure determination.

Convenient method for resolving degeneracies due to symmetry of the magnetic susceptibility tensor and its application to pseudo contact shift-based protein–protein complex structure determination

International Nuclear Information System (INIS)

Kobashigawa, Yoshihiro; Saio, Tomohide; Ushio, Masahiro; Sekiguchi, Mitsuhiro; Yokochi, Masashi; Ogura, Kenji; Inagaki, Fuyuhiko

2012-01-01

Pseudo contact shifts (PCSs) induced by paramagnetic lanthanide ions fixed in a protein frame provide long-range distance and angular information, and are valuable for the structure determination of protein–protein and protein–ligand complexes. We have been developing a lanthanide-binding peptide tag (hereafter LBT) anchored at two points via a peptide bond and a disulfide bond to the target proteins. However, the magnetic susceptibility tensor displays symmetry, which can cause multiple degenerated solutions in a structure calculation based solely on PCSs. Here we show a convenient method for resolving this degeneracy by changing the spacer length between the LBT and target protein. We applied this approach to PCS-based rigid body docking between the FKBP12-rapamycin complex and the mTOR FRB domain, and demonstrated that degeneracy could be resolved using the PCS restraints obtained from two-point anchored LBT with two different spacer lengths. The present strategy will markedly increase the usefulness of two-point anchored LBT for protein complex structure determination.

Electric field-induced valley degeneracy lifting in uniaxial strained graphene: Evidence from magnetophonon resonance

Science.gov (United States)

Assili, Mohamed; Haddad, Sonia; Kang, Woun

2015-03-01

A double peak structure in the magnetophonon resonance (MPR) spectrum of uniaxial strained graphene, under crossed electric and magnetic fields, is predicted. We focus on the Γ point optical phonon modes coupled to the inter-Landau level transitions 0 ⇆±1 where MPR is expected to be more pronounced at high magnetic field. We derive the frequency shifts and the broadenings of the longitudinal and transverse optical phonon modes taking into account the effect of the strain modified electronic spectrum on the electron-phonon coupling. We show that the MPR line for a given phonon mode acquires a double peak structure originating from the twofold valley degeneracy lifting. The latter is due to the different Landau level spacings in the two Dirac valleys resulting from the simultaneous action of the inplane electric field and the strain-induced Dirac cone tilt. We discuss the role of some key parameters such as disorder, strain, doping, and electric field amplitude on the emergence of the double peak structure.

Linear and nonlinear ion-acoustic waves in nonrelativistic quantum plasmas with arbitrary degeneracy

Science.gov (United States)

Haas, Fernando; Mahmood, Shahzad

2015-11-01

Linear and nonlinear ion-acoustic waves are studied in a fluid model for nonrelativistic, unmagnetized quantum plasma with electrons with an arbitrary degeneracy degree. The equation of state for electrons follows from a local Fermi-Dirac distribution function and applies equally well both to fully degenerate and classical, nondegenerate limits. Ions are assumed to be cold. Quantum diffraction effects through the Bohm potential are also taken into account. A general coupling parameter valid for dilute and dense plasmas is proposed. The linear dispersion relation of the ion-acoustic waves is obtained and the ion-acoustic speed is discussed for the limiting cases of extremely dense or dilute systems. In the long-wavelength limit, the results agree with quantum kinetic theory. Using the reductive perturbation method, the appropriate Korteweg-de Vries equation for weakly nonlinear solutions is obtained and the corresponding soliton propagation is analyzed. It is found that soliton hump and dip structures are formed depending on the value of the quantum parameter for the degenerate electrons, which affect the phase velocities in the dispersive medium.

The mass-sheet degeneracy and time-delay cosmography: analysis of the strong lens RXJ1131-1231

International Nuclear Information System (INIS)

Birrer, Simon; Amara, Adam; Refregier, Alexandre

2016-01-01

We present extended modelling of the strong lens system RXJ1131-1231 with archival data in two HST bands in combination with existing line-of-sight contribution and velocity dispersion estimates. Our focus is on source size and its influence on time-delay cosmography. We therefore examine the impact of mass-sheet degeneracy and especially the degeneracy pointed out by Schneider and Sluse (2013) [1] using the source reconstruction scale. We also extend on previous work by further exploring the effects of priors on the kinematics of the lens and the external convergence in the environment of the lensing system. Our results coming from RXJ1131-1231 are given in a simple analytic form so that they can be easily combined with constraints coming from other cosmological probes. We find that the choice of priors on lens model parameters and source size are subdominant for the statistical errors for H 0 measurements of this systems. The choice of prior for the source is sub-dominant at present (2% uncertainty on H 0 ) but may be relevant for future studies. More importantly, we find that the priors on the kinematic anisotropy of the lens galaxy have a significant impact on our cosmological inference. When incorporating all the above modeling uncertainties, we find H 0 = 86.6 +6.8 -6.9 km s -1 Mpc -1 , when using kinematic priors similar to other studies. When we use a different kinematic prior motivated by Barnabè et al. (2012) [2] but covering the same anisotropic range, we find H 0 = 74.5 +8.0 -7.8 km s -1 Mpc -1 . This means that the choice of kinematic modeling and priors have a significant impact on cosmographic inferences. The way forward is either to get better velocity dispersion measures which would down weight the impact of the priors or to construct physically motivated priors for the velocity dispersion model.

Lifting degeneracies in the oscillation parameters by a neutrino factory

International Nuclear Information System (INIS)

Aoki, Mayumi; Hagiwara, Kaoru; Okamura, Naotoshi

2005-01-01

We study the potential of a very long baseline neutrino oscillation experiment with a neutrino factory and a large segmented water-Cerenkov calorimeter detector in resolving the degeneracies in the neutrino oscillation parameters; the sign of the larger mass-squared difference δm 13 2 , the sign of vertical bar U μ3 vertical bar 2 (=sin 2 θ ATM )-1/2, and a possible two-fold ambiguity in the determination of the CP phase δ MNS . We find that the above problems can be resolved even if the particle charges are not measured. The following results are obtained in our exploratory study for a neutrino factory which delivers 10 21 decaying μ + and μ - at 10 GeV and a 100 kton detector which is placed 2100 km away and is capable of measuring the event energy and distinguishing e + /- from μ + /-, but not their charges. The sign of δm 13 2 can be determined for 4 vertical bar U e3 vertical bar 2 (1- vertical bar U e3 vertical bar 2 )=sin 2 2θ RCT -bar 0.008. That of sin 2 θ ATM -1/2 can be resolved for sin 2 2θ ATM =0.96 when sin 2 2θ RCT -bar 0.06. The CP-violating phase δ MNS can be uniquely constrained for sin 2 2θ RCT -bar 0.02 if its true value is around 90 o or 270 o , while it can be constrained for sin 2 2θ RCT -bar 0.03 if its true value is around 0 deg. or 180 deg

The Role of Antisymmetric Exchange on the Quantum Interference between States of Different Spin Length in a dimeric Molecular Nanomagnet.

Science.gov (United States)

Del Barco, Enrique

2009-03-01

We report direct evidence of quantum oscillations of the total spin length of a dimeric molecular nanomagnet through the observation of quantum interference associated with tunneling trajectories between states having different spin quantum numbers. As we outline, this is a consequence of the unique characteristics of a molecular Mn12 wheel which behaves as a (weak) ferromagnetic exchange-coupled molecular dimer: each half of the molecule acts as a single-molecule magnet (SMM), while the weak coupling between the two halves gives rise to an additional internal spin degree of freedom within the molecule, namely that its total spin may fluctuate. This extra degree of freedom accounts for several magnetization tunneling resonances that cannot be explained within the usual giant spin approximation. More importantly, the observation of quantum interference provides unambiguous evidence for the quantum mechanical superposition involving entangled states of both halves of the wheel. Magnetization results obtained in two other versions of this compound, in which the ligands have been modified, show that slight variations of the relative distance between the Mn ions determine whether the molecule behaves as a rigid magnetic unit of spin S = 7 or as two exchange-coupled halves of spin S = 7/2. We analyze the effect of the Dzyaloshinskii-Moriya antisymmetric exchange interaction in a molecule with a centre of inversion symmetry and propose a formal model to account for the observed broken degeneracy that preserves the molecular inversion symmetry.

A Family of Exactly Solvable Radial Quantum Systems on Space of Non-Constant Curvature with Accidental Degeneracy in the Spectrum

Directory of Open Access Journals (Sweden)

Orlando Ragnisco

2010-12-01

Full Text Available A novel family of exactly solvable quantum systems on curved space is presented. The family is the quantum version of the classical Perlick family, which comprises all maximally superintegrable 3-dimensional Hamiltonian systems with spherical symmetry. The high number of symmetries (both geometrical and dynamical exhibited by the classical systems has a counterpart in the accidental degeneracy in the spectrum of the quantum systems. This family of quantum problem is completely solved with the techniques of the SUSYQM (supersymmetric quantum mechanics. We also analyze in detail the ordering problem arising in the quantization of the kinetic term of the classical Hamiltonian, stressing the link existing between two physically meaningful quantizations: the geometrical quantization and the position dependent mass quantization.

New families of superintegrable systems from k-step rational extensions, polynomial algebras and degeneracies

International Nuclear Information System (INIS)

Marquette, Ian

2015-01-01

Four new families of two-dimensional quantum superintegrable systems are constructed from k-step extension of the harmonic oscillator and the radial oscillator. Their wavefunctions are related with Hermite and Laguerre exceptional orthogonal polynomials (EOP) of type III. We show that ladder operators obtained from alternative construction based on combinations of supercharges in the Krein-Adler and Darboux Crum (or state deleting and creating) approaches can be used to generate a set of integrals of motion and a corresponding polynomial algebra that provides an algebraic derivation of the full spectrum and total number of degeneracies. Such derivation is based on finite dimensional unitary representations (unirreps) and doesn't work for integrals build from standard ladder operators in supersymmetric quantum mechanics (SUSYQM) as they contain singlets isolated from excited states. In this paper, we also rely on a novel approach to obtain the finite dimensional unirreps based on the action of the integrals of motion on the wavefunctions given in terms of these EOP. We compare the results with those obtained from the Daskaloyannis approach and the realizations in terms of deformed oscillator algebras for one of the new families in the case of 1-step extension. This communication is a review of recent works. (paper)

Flavour and spin structure of linear baryons

International Nuclear Information System (INIS)

Kawarabayashi, K.; Kitakado, S.; Inami, T.

1979-01-01

Based on the string picture, a phenomenological model for baryons is constructed and their flavour symmetry, exchange degeneracy pattern and spin structure are studied. Baryons on leading trajectories are assumed to have the configuration of two quarks being attached to the ends of a linear string and the third sitting in the middle, called linear baryons. For such linear baryons, a unitarization scheme can be constructed in a manner similar to the dual unitarity scheme for mesons but without recourse to the 1/N expansion. It is found that the interchange interaction of the middle quark with one of the other two quarks at the ends of the string can give rise to a larger exchange degeneracy breaking of the baryon spectrum. With this non-planar correction, the model of linear baryons can account for the observed pattern of leading baryon states. (Auth.)

Atomic near-degeneracy for photoemission : Generality of 4f excitations

NARCIS (Netherlands)

Bagus, Paul S.; Broer, R; Ilton, Eugene S.

in a previous study of the 3s X-ray photoelectron spectra, XPS, of Mn, we identified a new intra-atomic many-body effect that lead to an similar to 50% increase in the predicted exchange splitting of the main high spin and low spin XPS peaks. The new many-body effect involved the promotion of one

Influence of quantum degeneracy and regeneration on the performance of Bose-Stirling refrigeration-cycles operated in different temperature regions

International Nuclear Information System (INIS)

Lin Bihong; Zhang Yue; Chen Jincan

2006-01-01

The Stirling refrigeration cycle using an ideal Bose-gas as the working substance is called the Bose-Stirling refrigeration cycle, which is different from other thermodynamic cycles such as the Carnot cycle, Ericsson cycle, Brayton cycle, Otto cycle, Diesel cycle and Atkinson cycle working with an ideal Bose gas and may be operated across the critical temperature of Bose-Einstein condensation of the Bose system. The performance of the cycle is investigated, based on the equation of state of an ideal Bose gas. The inherent regenerative losses of the cycle are considered and the coefficient of performance and the amount of refrigeration of the cycle are calculated. The results obtained here are compared with those derived from the classical Stirling refrigeration cycle, using an ideal gas as the working substance. The influence of quantum degeneracy and inherent regenerative losses on the performance of the Bose Stirling refrigeration cycle operated in different temperature regions is discussed in detail, and consequently, general performance characteristics of the cycle are revealed

Massive Degeneracy and Goldstone Bosons: A Challenge for the Light Cone

Energy Technology Data Exchange (ETDEWEB)

Weinstein, Marvin; /SLAC

2010-10-27

gives rise to this sort of pattern of degeneracy when the physical volume of space becomes large.

Re-gauging groupoid, symmetries and degeneracies for graph Hamiltonians and applications to the Gyroid wire network

Energy Technology Data Exchange (ETDEWEB)

Kaufmann, Ralph M.; Khlebnikov, Sergei; Wehefritz-Kaufmann, Birgit

2012-08-15

Motivated by Harper Hamiltonians on skeletal graphs and their C{sup *}-geometry, we study a certain class of graph Hamiltonians. These Hamiltonians can be thought of as a finite groupoid representation in separable Hilbert spaces. Here the groupoid is the path groupoid of a finite graph. Given such a setup, we consider the possible matrix versions of the Hamiltonian, which are indexed by the choice of a rooted spanning tree and an order of the vertices. The first result is that all the matrix representations are linked to each other via the conjugation action of a re-gauging groupoid. We furthermore show that the symmetries of the underlying graph give rise to an action on the Hamiltonians of a group of extended symmetries. The new concept for the extension is to allow phase transformations on the vertices. In the commutative case, we prove that the extended symmetries act via a projective representation giving rise to isotypical decompositions and super-selection rules. We then apply these results to the PDG and honeycomb graphs using representation theory for projective groups and show that all the degeneracies in the spectra are consequences of these enhanced symmetries. This includes the Dirac points of the Gyroid and the honeycomb.

Origin of parameter degeneracy and molecular shape relationships in geometric-flow calculations of solvation free energies

Energy Technology Data Exchange (ETDEWEB)

Daily, Michael D. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Chun, Jaehun [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Heredia-Langner, Alejandro [National Security Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Wei, Guowei [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States); Baker, Nathan A. [Computational and Statistical Analytics Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2013-11-28

Implicit solvent models are important tools for calculating solvation free energies for chemical and biophysical studies since they require fewer computational resources but can achieve accuracy comparable to that of explicit-solvent models. In past papers, geometric flow-based solvation models have been established for solvation analysis of small and large compounds. In the present work, the use of realistic experiment-based parameter choices for the geometric flow models is studied. We find that the experimental parameters of solvent internal pressure p = 172 MPa and surface tension γ = 72 mN/m produce solvation free energies within 1 RT of the global minimum root-mean-squared deviation from experimental data over the expanded set. Our results demonstrate that experimental values can be used for geometric flow solvent model parameters, thus eliminating the need for additional parameterization. We also examine the correlations between optimal values of p and γ which are strongly anti-correlated. Geometric analysis of the small molecule test set shows that these results are inter-connected with an approximately linear relationship between area and volume in the range of molecular sizes spanned by the data set. In spite of this considerable degeneracy between the surface tension and pressure terms in the model, both terms are important for the broader applicability of the model.

Collective impurity effects in the Heisenberg triangular antiferromagnet

International Nuclear Information System (INIS)

Maryasin, V S; Zhitomirsky, M E

2015-01-01

We theoretically investigate the Heisenberg antiferromagnet on a triangular lattice doped with nonmagnetic impurities. Two nontrivial effects resulting from collective impurity behavior are predicted. The first one is related to presence of uncompensated magnetic moments localized near vacancies as revealed by the low-temperature Curie tail in the magnetic susceptibility. These moments exhibit an anomalous growth with the impurity concentration, which we attribute to the clustering mechanism. In an external magnetic field, impurities lead to an even more peculiar phenomenon lifting the classical ground-state degeneracy in favor of the conical state. We analytically demonstrate that vacancies spontaneously generate a positive biquadratic exchange, which is responsible for the above degeneracy lifting

Segmented heat exchanger

Science.gov (United States)

Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

2010-12-14

A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

Exchange rate rebounds after foreign exchange market interventions

Science.gov (United States)

Hoshikawa, Takeshi

2017-03-01

This study examined the rebounds in the exchange rate after foreign exchange intervention. When intervention is strongly effective, the exchange rate rebounds at next day. The effect of intervention is reduced slightly by the rebound after the intervention. The exchange rate might have been 67.12-77.47 yen to a US dollar without yen-selling/dollar-purchasing intervention of 74,691,100 million yen implemented by the Japanese government since 1991, in comparison to the actual exchange rate was 103.19 yen to the US dollar at the end of March 2014.

Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

Energy Technology Data Exchange (ETDEWEB)

Levy, Mel, E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W., E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario (Canada)

2014-05-14

Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.

Symmetry analysis in neutron diffraction studies of magnetic structures. IV

International Nuclear Information System (INIS)

Izyumov, Yu.A.; Naish, V.E.; Petrov, S.B.

1979-01-01

By analyzing the exchange Hamiltonian, the authors develop the technique of determining the magnetic structures liable to occur in a crystal. The technique rests on Bertaut's idea that the exchange eigenfunction corresponds to some magnetic structure. A technically simple and efficient method of diagonalizing the exchange matrix is worked out using the devices of space group representation theory. A method is presented to find the magnetic structures with equal exchange energy (exchange multiplets). The occcurrence of exchange multiplets results from the additional invariance of the exchange Hamiltonian under rotation of all the spins. The degeneracy within the exchange multiplet may be the reason why some magnetic structures arise not according to one irreducible representation of the space group. The theory is illustrated with reference to an example of the magnetic structure of spinels. (Auth.)

Exchange functional by a range-separated exchange hole

International Nuclear Information System (INIS)

Toyoda, Masayuki; Ozaki, Taisuke

2011-01-01

An approximation to the exchange-hole density is proposed for the evaluation of the exact exchange energy in electronic structure calculations within the density-functional theory and the Kohn-Sham scheme. Based on the localized nature of density matrix, the exchange hole is divided into the short-range (SR) and long-range (LR) parts by using an adequate filter function, where the LR part is deduced by matching of moments with the exactly calculated SR counterpart, ensuring the correct asymptotic -1/r behavior of the exchange potential. With this division, the time-consuming integration is truncated at a certain interaction range, largely reducing the computation cost. The total energies, exchange energies, exchange potentials, and eigenvalues of the highest-occupied orbitals are calculated for the noble-gas atoms. The close agreement of the results with the exact values suggests the validity of the approximation.

Non-planar corrections to the Pomeron and reggeons in the dual unitarity scheme

International Nuclear Information System (INIS)

Uschersohn, J.

1976-03-01

A special class of non-planar diagrams is studied, those in which the produced clusters are crossed. Insertion of these diagrams in the reggeon propagators accounts for exchange degeneracy breaking. The even signature reggeons get their intercept promoted to a larger value, while the odd signature ones are left unchanged. (author)

Shedding Light on the EOS-Gravity Degeneracy and Constraining the Nuclear Symmetry Energy from the Gravitational Binding Energy of Neutron Stars

Directory of Open Access Journals (Sweden)

He Xiao-Tao

2016-01-01

Full Text Available A thorough understanding of properties of neutron stars requires both a reliable knowledge of the equation of state (EOS of super-dense nuclear matter and the strong-field gravity theories simultaneously. To provide information that may help break this EOS-gravity degeneracy, we investigate effects of nuclear symmetry energy on the gravitational binding energy of neutron stars within GR and the scalar-tensor subset of alternative gravity models. We focus on effects of the slope L of nuclear symmetry energy at saturation density and the high-density behavior of nuclear symmetry energy. We find that the variation of either the density slope L or the high-density behavior of nuclear symmetry energy leads to large changes in the binding energy of neutron stars. The difference in predictions using the GR and the scalar-tensor theory appears only for massive neutron stars, and even then is significantly smaller than the difference resulting from variations in the symmetry energy.

Automated exchange transfusion and exchange rate.

Science.gov (United States)

Funato, M; Shimada, S; Tamai, H; Taki, H; Yoshioka, Y

1989-10-01

An automated blood exchange transfusion (BET) with a two-site technique has been devised by Goldmann et al and by us, using an infusion pump. With this method, we successfully performed exchange transfusions 189 times in the past four years on 110 infants with birth weights ranging from 530 g to 4,000 g. The exchange rate by the automated method was compared with the rate by Diamond's method. Serum bilirubin (SB) levels before and after BET and the maximal SB rebound within 24 hours after BET were: 21.6 +/- 2.4, 11.5 +/- 2.2, and 15.0 +/- 1.5 mg/dl in the automated method, and 22.0 +/- 2.9, 11.2 +/- 2.5, and 17.7 +/- 3.2 mg/dl in Diamond's method, respectively. The result showed that the maximal rebound of the SB level within 24 hours after BET was significantly lower in the automated method than in Diamond's method (p less than 0.01), though SB levels before and after BET were not significantly different between the two methods. The exchange rate was also measured by means of staining the fetal red cells (F cells) both in the automated method and in Diamond's method, and comparing them. The exchange rate of F cells in Diamond's method went down along the theoretical exchange curve proposed by Diamond, while the rate in the automated method was significantly better than in Diamond's, especially in the early stage of BET (p less than 0.01). We believe that the use of this automated method may give better results than Diamond's method in the rate of exchange, because this method is performed with a two-site technique using a peripheral artery and vein.

Heat exchanger

International Nuclear Information System (INIS)

Dostatni, A.W.; Dostatni, Michel.

1976-01-01

In the main patent, a description was given of a heat exchanger with an exchange surface in preformed sheet metal designed for the high pressure and temperature service particularly encountered in nuclear pressurized water reactors and which is characterised by the fact that it is composed of at least one exchanger bundle sealed in a containment, the said bundle or bundles being composed of numerous juxtaposed individual compartments whose exchange faces are built of preformed sheet metal. The present addendun certificate concerns shapes of bundles and their positioning methods in the exchanger containment enabling its compactness to be increased [fr

Abstracts of the workshop on orbital ordering and fluctuations in d- and f-electron systems

International Nuclear Information System (INIS)

Ueda, Kazuo; Hotta, Takashi

2002-12-01

Strongly correlated f- and d-electron systems including heavy Fermion systems and transition metal oxides are important source of exciting new phenomena in condensed matter physics. Recently it has been recognized in more profound way that the orbital degeneracy of the f- and d-electrons plays very important role underlying those exotic phenomena. The idea of the present workshop is to bring active researchers in the field together and to exchange ideas in informal atmosphere. In the workshop, twenty seven papers were presented and the following subjects were discussed: orbital ordering in transition metal oxides, role of orbital degeneracy in heavy Fermion systems and effect of geometrical frustration on orbital fluctuations. (author)

0 - π Quantum transition in a carbon nanotube Josephson junction: Universal phase dependence and orbital degeneracy

Science.gov (United States)

Delagrange, R.; Weil, R.; Kasumov, A.; Ferrier, M.; Bouchiat, H.; Deblock, R.

2018-05-01

In a quantum dot hybrid superconducting junction, the behavior of the supercurrent is dominated by Coulomb blockade physics, which determines the magnetic state of the dot. In particular, in a single level quantum dot singly occupied, the sign of the supercurrent can be reversed, giving rise to a π-junction. This 0 - π transition, corresponding to a singlet-doublet transition, is then driven by the gate voltage or by the superconducting phase in the case of strong competition between the superconducting proximity effect and Kondo correlations. In a two-level quantum dot, such as a clean carbon nanotube, 0- π transitions exist as well but, because more cotunneling processes are allowed, are not necessarily associated to a magnetic state transition of the dot. In this proceeding, after a review of 0- π transitions in Josephson junctions, we present measurements of current-phase relation in a clean carbon nanotube quantum dot, in the single and two-level regimes. In the single level regime, close to orbital degeneracy and in a regime of strong competition between local electronic correlations and superconducting proximity effect, we find that the phase diagram of the phase-dependent transition is a universal characteristic of a discontinuous level-crossing quantum transition at zero temperature. In the case where the two levels are involved, the nanotube Josephson current exhibits a continuous 0 - π transition, independent of the superconducting phase, revealing a different physical mechanism of the transition.

Ion exchange equilibrium constants

CERN Document Server

Marcus, Y

2013-01-01

Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

The behavior of plasma with an arbitrary degree of degeneracy of electron gas in the conductive layer

Science.gov (United States)

Latyshev, A. V.; Gordeeva, N. M.

2017-09-01

We obtain an analytic solution of the boundary problem for the behavior (fluctuations) of an electron plasma with an arbitrary degree of degeneracy of the electron gas in the conductive layer in an external electric field. We use the kinetic Vlasov-Boltzmann equation with the Bhatnagar-Gross-Krook collision integral and the Maxwell equation for the electric field. We use the mirror boundary conditions for the reflections of electrons from the layer boundary. The boundary problem reduces to a one-dimensional problem with a single velocity. For this, we use the method of consecutive approximations, linearization of the equations with respect to the absolute distribution of the Fermi-Dirac electrons, and the conservation law for the number of particles. Separation of variables then helps reduce the problem equations to a characteristic system of equations. In the space of generalized functions, we find the eigensolutions of the initial system, which correspond to the continuous spectrum (Van Kampen mode). Solving the dispersion equation, we then find the eigensolutions corresponding to the adjoint and discrete spectra (Drude and Debye modes). We then construct the general solution of the boundary problem by decomposing it into the eigensolutions. The coefficients of the decomposition are given by the boundary conditions. This allows obtaining the decompositions of the distribution function and the electric field in explicit form.

Clima, cerebro y degeneración en Cabanis Climate, brain, and degeneration in Cabanis

Directory of Open Access Journals (Sweden)

Sandra Caponi

2009-12-01

Full Text Available Son analizados los argumentos defendidos por Cabanis en el Rapports du physique et du moral de l'homme, tomando como punto de partida las Memorias Octava y Novena. Estas Memorias, dedicadas a analizar las influencias del régimen y del clima, permiten leer de otro modo los argumentos utilizados por Cabanis para explicar la relación entre las características físicas y los hábitos morales de individuos y razas. Son analizadas las deudas con la historia natural, particularmente con la teoría de la degeneración de Buffon; con la tradición médica hipocrática, fundamentalmente con la teoría de los humores, y con los estudios de anatomía y patología cerebral. Finalmente, examinamos el papel que la medicina y la higiene, pensadas como ciencias humanas y morales, poseen en los proyetos de la regeneración de la especie humana.This analysis of the arguments defended by Cabanis in Rapports du physique et du moral de l'homme takes as its point of departure his eighth and ninth Memoirs, which focus on analyzing the influences of regime and climate. These writings afford a new reading of the arguments Cabanis used to explain the relation between the physical traits and moral habits of individuals and races. The article analyzes his debts to natural history, especially Buffon's theory of degeneration; to the Hippocratic tradition, above all the humor theory; and to studies of brain anatomy and pathology. Lastly, it examines the role that the human and moral sciences of medicine and hygiene play in the regeneration of the human species.

Exchange and Dzyaloshinskii-Moriya interactions in bulk FeGe: Effects of atomic vacancies

Science.gov (United States)

Loh, G. C.; Gan, C. K.

2017-05-01

We examine the effects of atomic vacancies on the (1) spin interaction, and (2) electronic character in the cubic B20 chiral magnet FeGe. For the former, Heisenberg exchange and Dzyaloshinskii-Moriya (DM) interactions are studied. The latter is done via a particular Wannier flavor of the Hamiltonian in the form of maximally-localized Wannier functions (MLWFs). Using first-principles calculations based on full-potential linearized augmented plane-wave (FLAPW)-based density functional theory (DFT), the spin order of bulk FeGe, in its pristine form, and with a Fe (Fe75%Ge100%) or Ge vacancy (Fe100%Ge75%) is investigated. Despite the presence of vacancies, the ground state of FeGe remains helimagnetic, i.e. spin spirals in FeGe are fairly robust. The energetic stability of FeGe increases in the presence of the vacancies. The spiral size is increased by approximately 40%, suggesting that vacancies can be introduced to manipulate the chiral order. The vacancies lift the band degeneracy in the valence manifold of the Wannier-interpolated band structures. Only the spin-down Fermi surfaces are substantially different between the pristine and defective FeGe; it is electron-like in the pristine case, but largely hole-like in the defective ones. The Ge vacancy splits the Fermi surface more than the Fe vacancy. The Heisenberg exchange between nearest Fe pairs is ferromagnetic in pristine FeGe. This Fe-Fe interaction remains ferromagnetic, albeit a slight decrease in strength, in the presence of a Fe vacancy. In contrast, a Ge vacancy in FeGe induces anti-ferromagnetism between nearest Fe pairs. By including spin-orbit coupling effects, we find that the DM interaction of defective FeGe is reversed in sign, and it is more uniform in strength along the three highly symmetric directions, relative to that in pristine FeGe. All in all, the versatility of FeGe makes it an excellent functional material, especially in data storage and spintronics applications.

Exchange rate policy

Directory of Open Access Journals (Sweden)

Plačkov Slađana

2013-01-01

Full Text Available Small oscillations of exchange rate certainly affect the loss of confidence in the currency (Serbian dinar, CSD and because of the shallow market even the smallest change in the supply and demand leads to a shift in exchange rate and brings uncertainty. Some economists suggest that the course should be linked to inflation and thus ensure predictable and stable exchange rates. Real exchange rate or slightly depressed exchange rate will encourage the competitiveness of exporters and perhaps ensure the development of new production lines which, in terms of overvalued exchange rate, had no economic justification. Fixed exchange rate will bring lower interest rates, lower risk and lower business uncertainty (uncertainty avoidance, but Serbia will also reduce foreign exchange reserves by following this trend. On the other hand, a completely free exchange rate, would lead to a (real fall of Serbian currency, which in a certain period would lead to a significant increase in exports, but the consequences for businessmen and citizens with loans pegged to the euro exchange rate, would be disastrous. We will pay special attention to the depreciation of the exchange rate, as it is generally favorable to the export competitiveness of Serbia and, on the other hand, it leads to an increase in debt servicing costs of the government as well as of the private sector. Oscillations of the dinar exchange rate, appreciation and depreciation, sometimes have disastrous consequences on the economy, investors, imports and exports. In subsequent work, we will observe the movement of the dinar exchange rate in Serbia, in the time interval 2009-2012, in order to strike a balance and maintain economic equilibrium. A movement of foreign currencies against the local currency is controlled in the foreign exchange market, so in case economic interests require, The National Bank of Serbia (NBS, on the basis of arbitrary criteria, can intervene in the market.

Exchange market pressure

NARCIS (Netherlands)

Jager, H.; Klaassen, F.; Durlauf, S.N.; Blume, L.E.

2010-01-01

Currencies can be under severe pressure in the foreign exchange market, but in a fixed (or managed) exchange rate regime that is not fully visible via the change in the exchange rate. Exchange market pressure (EMP) is a concept developed to nevertheless measure the pressure in such cases. This

EXTERNALITIES IN EXCHANGE NETWORKS AN ADAPTATION OF EXISTING THEORIES OF EXCHANGE NETWORKS

NARCIS (Netherlands)

Dijkstra, Jacob

2009-01-01

The present paper extends the focus of network exchange research to externalities in exchange networks. Externalities of exchange are defined as direct effects on an actor's utility, of an exchange in which this actor is not involved. Existing theories in the field of network exchange do not inform

Level shift and charm mass: a test of asymptotic planarity

International Nuclear Information System (INIS)

Palmer, W.F.; Pinsky, S.S.; Shi, C.C.

1976-01-01

Level shifts and mixings away from exact exchange degeneracy are examined with respect to the ''asymptotic planarity'' predictions of Chew and Rosenzweig. It is found that the data in the J/sup P/ = 0 - , 1 - , and 2 + multiplets support neither the general shape nor the special relation proposed by Chew and Rosenzweig for the tensor and vector ''cylinder'' corrections

Heat exchanger

International Nuclear Information System (INIS)

Leigh, D.G.

1976-01-01

The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

Fine structure of an exciton coupled to a single Fe2 + ion in a CdSe/ZnSe quantum dot

Science.gov (United States)

Smoleński, T.; Kazimierczuk, T.; Goryca, M.; Pacuski, W.; Kossacki, P.

2017-10-01

We present a polarization-resolved photoluminescence study of the exchange interaction effects in a prototype system consisting of an individual Fe2 + ion and a single neutral exciton confined in a CdSe/ZnSe quantum dot. A maximal possible number of eight fully linearly polarized lines in the bright exciton emission spectrum is observed, evidencing complete degeneracy lifting in the investigated system. We discuss the conditions required for such a scenario to take place: anisotropy of the electron-hole interaction and the zero-field splitting of the Fe2 + ion spin states. Neglecting either of these components is shown to restore partial degeneracy of the transitions, making the excitonic spectrum similar to those previously reported for all other systems of quantum dots with single magnetic dopants.

Estimating Exchange Market Pressure and the Degree of Exchange Market Intervention for Finland during the Floating Exchange Rate Regime

OpenAIRE

Pösö, Mika; Spolander, Mikko

1997-01-01

In this paper, we use a fairly simple monetary macro model to calculate the quarterly measures of exchange market pressure and the degree of the Bank of Finland's intervention during the time the markka was floated. Exchange market pressure measures the size of the exchange rate change that would have occurred if the central bank had unexpectedly refrained from intervening in the foreign exchange market. Intervention activity of the central bank is measured as the proportion of exchange marke...

A continuous exchange factor method for radiative exchange in enclosures with participating media

International Nuclear Information System (INIS)

Naraghi, M.H.N.; Chung, B.T.F.; Litkouhi, B.

1987-01-01

A continuous exchange factor method for analysis of radiative exchange in enclosures is developed. In this method two types of exchange functions are defined, direct exchange function and total exchange function. Certain integral equations relating total exchange functions to direct exchange functions are developed. These integral equations are solved using Gaussian quadrature integration method. The results obtained based on the present approach are found to be more accurate than those of the zonal method

Electron exchange reaction in anion exchangers as observed in uranium isotope separation

International Nuclear Information System (INIS)

Obanawa, Heiichiro; Takeda, Kunihiko; Seko, Maomi

1991-01-01

The mechanism of electron exchange in an ion exchanger, as occurring between U 4+ and UO 2 2+ in uranium isotope separation, was investigated. The height of the separation unit (H q ) in the presence of metal ion catalysts, as obtained from the separation experiments, was found to be almost coincident with the theoretical value of H q as calculated on the basis of the intrasolution acceleration mechanism of the metal ion, suggesting that the electron exchange mechanism in the ion-exchanger is essentially the same as that in the solution when metal ion catalysts are present. Separation experiments with no metal ion catalyst, on the other hand, showed the electron exchange reaction in the ion exchanger to be substantially higher than that in the solution, suggesting an acceleration of the electron exchange reaction by the ion-exchanger which is due to the close existence of higher order Cl - complexes of UO 2 2+ and U 4+ in the vicinity of the ion-exchange group. (author)

Investigation of Chemical Exchange at Intermediate Exchange Rates using a Combination of Chemical Exchange Saturation Transfer (CEST) and Spin-Locking methods (CESTrho)

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2011-01-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer (CEST) and T1ρ magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. PMID:22009759

Investigation of chemical exchange at intermediate exchange rates using a combination of chemical exchange saturation transfer (CEST) and spin-locking methods (CESTrho).

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2012-07-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer and T(1)(ρ) magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. Copyright © 2011 Wiley Periodicals, Inc.

Superlattice formation lifting degeneracy protected by nonsymmorphic symmetry through a metal-insulator transition in RuAs

Science.gov (United States)

Kotegawa, Hisashi; Takeda, Keiki; Kuwata, Yoshiki; Hayashi, Junichi; Tou, Hideki; Sugawara, Hitoshi; Sakurai, Takahiro; Ohta, Hitoshi; Harima, Hisatomo

2018-05-01

A single crystal of RuAs obtained with the Bi-flux method shows obvious successive metal-insulator transitions at TMI 1˜255 K and TMI 2˜195 K. The x-ray diffraction measurement reveals the formation of a superlattice of 3 ×3 ×3 of the original unit cell below TMI 2, accompanied by a change of the crystal system from the orthorhombic structure to the monoclinic one. Simple dimerization of the Ru ions is not seen in the ground state. The multiple As sites observed in the nuclear quadrupole resonance spectrum also demonstrate the formation of the superlattice in the ground state, which is clarified to be nonmagnetic. The divergence in 1 /T1 at TMI 1 shows that a symmetry lowering by the metal-insulator transition is accompanied by strong critical fluctuations of some degrees of freedom. Using the structural parameters in the insulating state, the first-principles calculation reproduces successfully the reasonable size of nuclear quadrupole frequencies νQ for the multiple As sites, ensuring the high validity of the structural parameters. The calculation also gives a remarkable suppression in the density of states near the Fermi level, although the gap opening is insufficient. A coupled modulation of the calculated Ru d -electron numbers and the crystal structure proposes the formation of a charge density wave in RuAs. Some lacking factors remain, but it is shown that a lifting of degeneracy protected by the nonsymmorphic symmetry through the superlattice formation is a key ingredient for the metal-insulator transition in RuAs.

On one pion exchange potential with quark exchange in the resonating group method

International Nuclear Information System (INIS)

Braeuer, K.; Faessler, A.; Fernandez, F.; Shimizu, K.

1985-01-01

The effect of quark exchange between different nucleons on the one pion exchange potential is studied in the framework of the resonating group method. The calculated phase shifts including the one pion exchange potential with quark exchange in addition to the one gluon plus sigma meson exchange are shown to be consistent with experiments. Especially the p-wave phase shifts are improved by taking into account the quark exchange on the one pion exchange potential. (orig.)

AS ABOVE, SO BELOW: EXPLOITING MASS SCALING IN BLACK HOLE ACCRETION TO BREAK DEGENERACIES IN SPECTRAL INTERPRETATION

International Nuclear Information System (INIS)

Markoff, Sera; Silva, Catia V.; Nowak, Michael A.; Gallo, Elena; Plotkin, Richard M.; Hynes, Robert; Wilms, Jörn; Maitra, Dipankar; Drappeau, Samia

2015-01-01

Over the past decade, evidence has mounted that several aspects of black hole (BH) accretion physics proceed in a mass-invariant way. One of the best examples of this scaling is the empirical “fundamental plane of BH accretion” relation linking mass, radio, and X-ray luminosity over eight orders of magnitude in BH mass. The currently favored theoretical interpretation of this relation is that the physics governing power output in weakly accreting BHs depends more on relative accretion rate than on mass. In order to test this theory, we explore whether a mass-invariant approach can simultaneously explain the broadband spectral energy distributions from two BHs at opposite ends of the mass scale but that are at similar Eddington accretion fractions. We find that the same model, with the same value of several fitted physical parameters expressed in mass-scaling units to enforce self-similarity, can provide a good description of two data sets from V404 Cyg and M81*, a stellar and supermassive BH, respectively. Furthermore, only one of several potential emission scenarios for the X-ray band is successful, suggesting it is the dominant process driving the fundamental plane relation at this accretion rate. This approach thus holds promise for breaking current degeneracies in the interpretation of BH high-energy spectra and for constructing better prescriptions of BH accretion for use in various local and cosmological feedback applications

Spitzer Opens New Path to Break Classic Degeneracy for Jupiter-mass Microlensing Planet OGLE-2017-BLG-1140Lb

Science.gov (United States)

Calchi Novati, S.; Skowron, J.; Jung, Y. K.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Yee, J. C.; Zhu, W.; Spitzer Team; Udalski, A.; Szymański, M. K.; Mróz, P.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Gould, A.; Han, C.; Hwang, K.-H.; Ryu, Y.-H.; Shin, I.-G.; Zang, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration

2018-06-01

We analyze the combined Spitzer and ground-based data for OGLE-2017-BLG-1140 and show that the event was generated by a Jupiter-class ({m}p≃ 1.6 {M}{{J}{{u}}{{p}}}) planet orbiting a mid-late M dwarf (M≃ 0.2 {M}ȯ ) that lies {D}LS}≃ 1.0 {kpc} in the foreground of the microlensed Galactic-bar source star. The planet–host projected separation is {a}\\perp ≃ 1.0 {au}, i.e., well beyond the snow line. By measuring the source proper motion {{\\boldsymbol{μ }}}s from ongoing long-term OGLE imaging and combining this with the lens-source relative proper motion {{\\boldsymbol{μ }}}rel} derived from the microlensing solution, we show that the lens proper motion {{\\boldsymbol{μ }}}l={{\\boldsymbol{μ }}}rel}+{{\\boldsymbol{μ }}}s is consistent with the lens lying in the Galactic disk, although a bulge lens is not ruled out. We show that while the Spitzer and ground-based data are comparably well fitted by planetary (i.e., binary-lens (2L1S)) and binary-source (1L2S) models, the combination of Spitzer and ground-based data decisively favors the planetary model. This is a new channel to resolve the 2L1S/1L2S degeneracy, which can be difficult to break in some cases.

La miseria de la degeneración: el materialismo de Buffon y las 'limitaciones' de su transformismo The misery of degeneration: Buffon's materialism and the 'limitations' of his transformism

Directory of Open Access Journals (Sweden)

Gustavo Caponi

2009-09-01

Full Text Available En "De la degeneración des animales", de 1766, Buffon sostuvo un 'transformismo limitado' que, doce años después, en Las épocas de la naturaleza, sería complementado por una teoría materialista sobre el origen de la vida que ponía en evidencia que, para el cientista, esa alternativa estaba vedada: las condiciones bajo las cuales los seres vivos desarrollan sus existencias podrían explicar cómo las diferentes especies que componen los distintos géneros de animales se habrían formado a partir de la degeneración de una especie originaria. Pero, la constitución de esas múltiples cepas primigenias sólo podría explicarse por un súbito proceso de generación espontánea. Una limitación inherente al propio sistema de ideas que lo había llevado hasta ese transformismo limitado: la propia teoría de la generación y la reproducción que le servía de base inhibía la posibilidad de su radicalización.In "Of the degeneration of animals" (1766, Buffon espoused a kind of limited transformism. Yet twelve years later, in Epochs of Nature, he supplemented this with a materialist theory on the origin of life that left no room for this alternative: the conditions under which living beings develop could explain how the different species within each animal genus had formed through the degeneration of an originating species. But the formation of these multiple, originating varieties could only be explained by a sudden process of spontaneous generation. A limitation inherent to the very system of ideas that had taken Buffon to limited transformism - the underlying theory of generation and reproduction - preempted the possibility of its radicalization.

Minimizing Back Exchange in the Hydrogen Exchange-Mass Spectrometry Experiment

Science.gov (United States)

Walters, Benjamin T.; Ricciuti, Alec; Mayne, Leland; Englander, S. Walter

2012-12-01

The addition of mass spectrometry (MS) analysis to the hydrogen exchange (HX) proteolytic fragmentation experiment extends powerful HX methodology to the study of large biologically important proteins. A persistent problem is the degradation of HX information due to back exchange of deuterium label during the fragmentation-separation process needed to prepare samples for MS measurement. This paper reports a systematic analysis of the factors that influence back exchange (solution pH, ionic strength, desolvation temperature, LC column interaction, flow rates, system volume). The many peptides exhibit a range of back exchange due to intrinsic amino acid HX rate differences. Accordingly, large back exchange leads to large variability in D-recovery from one residue to another as well as one peptide to another that cannot be corrected for by reference to any single peptide-level measurement. The usual effort to limit back exchange by limiting LC time provides little gain. Shortening the LC elution gradient by 3-fold only reduced back exchange by ~2 %, while sacrificing S/N and peptide count. An unexpected dependence of back exchange on ionic strength as well as pH suggests a strategy in which solution conditions are changed during sample preparation. Higher salt should be used in the first stage of sample preparation (proteolysis and trapping) and lower salt (<20 mM) and pH in the second stage before electrospray injection. Adjustment of these and other factors together with recent advances in peptide fragment detection yields hundreds of peptide fragments with D-label recovery of 90 % ± 5 %.

Minimizing back exchange in the hydrogen exchange-mass spectrometry experiment.

Science.gov (United States)

Walters, Benjamin T; Ricciuti, Alec; Mayne, Leland; Englander, S Walter

2012-12-01

The addition of mass spectrometry (MS) analysis to the hydrogen exchange (HX) proteolytic fragmentation experiment extends powerful HX methodology to the study of large biologically important proteins. A persistent problem is the degradation of HX information due to back exchange of deuterium label during the fragmentation-separation process needed to prepare samples for MS measurement. This paper reports a systematic analysis of the factors that influence back exchange (solution pH, ionic strength, desolvation temperature, LC column interaction, flow rates, system volume). The many peptides exhibit a range of back exchange due to intrinsic amino acid HX rate differences. Accordingly, large back exchange leads to large variability in D-recovery from one residue to another as well as one peptide to another that cannot be corrected for by reference to any single peptide-level measurement. The usual effort to limit back exchange by limiting LC time provides little gain. Shortening the LC elution gradient by 3-fold only reduced back exchange by ~2%, while sacrificing S/N and peptide count. An unexpected dependence of back exchange on ionic strength as well as pH suggests a strategy in which solution conditions are changed during sample preparation. Higher salt should be used in the first stage of sample preparation (proteolysis and trapping) and lower salt (<20 mM) and pH in the second stage before electrospray injection. Adjustment of these and other factors together with recent advances in peptide fragment detection yields hundreds of peptide fragments with D-label recovery of 90% ± 5%.

How did China's foreign exchange reform affect the efficiency of foreign exchange market?

Science.gov (United States)

Ning, Ye; Wang, Yiming; Su, Chi-wei

2017-10-01

This study compares the market efficiency of China's onshore and offshore foreign exchange markets before and after the foreign exchange reform on August 11, 2015. We use the multifractal detrended fluctuation analysis of the onshore and offshore RMB/USD spot exchange rate series as basis. We then find that the onshore foreign exchange market before the reform has the lowest market efficiency, which increased after the reform. The offshore foreign exchange market before the reform has the highest market efficiency, which dropped after the reform. This finding implies the increased efficiency of the onshore foreign exchange market and the loss of efficiency in the offshore foreign exchange market. We also find that the offshore foreign exchange market is more efficient than the onshore market and that the gap shrank after the reform. Changes in intervention of the People's Bank of China since the reform is a possible explanation for the changes in the efficiency of the foreign exchange market.

Investigating the effects of liquidity and exchange rate on Tehran Stock Exchange

Directory of Open Access Journals (Sweden)

Younos Vakil Alroaia

2014-08-01

Full Text Available This paper presents an empirical investigation to study the effects of two macroeconomic factors; namely exchange rate and liquidity on stock index. The proposed study was applied in Iran and on major index of Tehran Stock Exchange over the period 2001-2011. They reported that the currency exchange maintained negative impact on stock exchange for the period of investigation. This is due to the fact that when currency devalued, working capital decreases and firms did not enough money to purchase raw materials, pay wages, etc. In addition, liquidity marinated a direct and positive relationship with exchange index. However, the impact of liquidity seems to be bigger than currency exchange.

Theory and design of heat exchanger : air cooled plate, spiral heat exchanger

International Nuclear Information System (INIS)

Min, Ui Dong

1960-02-01

This book deals with air cooled heat exchanger, which introduces heat rejection system, wet surface cooler in new from, explanation of structure and design, materials, basic design like plenums chambers and fan ring, finned tube fouling factor, airflow in forced draft and fan design. It also tells of plate heat exchanger and spiral heat exchanger giving descriptions of summary, selection, basic design, device and safety function, maintenance, structure of plate heat exchanger, frames and connector plate and, basic things of spiral tube heat exchanger.

Reactor fuel exchanging facility

International Nuclear Information System (INIS)

Kubota, Shin-ichi.

1981-01-01

Purpose: To enable operation of an emergency manual operating mechanism for a fuel exchanger with all operatorless trucks and remote operation of a manipulator even if the exchanger fails during the fuel exchanging operation. Constitution: When a fuel exchanging system fails while connected to a pressure tube of a nuclear reactor during a fuel exchanging operation, a stand-by self-travelling truck automatically runs along a guide line to the position corresponding to the stopping position at that time of the fuel exchanger based on a command from a central control chamber. At this time the truck is switched to manual operation, and approaches the exchanger while being monitored through a television camera and then stops. Then, a manipurator is connected to the emergency manual operating mechanism of the exchanger, and is operated through necessary emergency steps by driving the snout, the magazine, the grab or the like in the exchanger in response to the problem, and necessary operations for the emergency treatment are thus performed. (Sekiya, K.)

Theory and design of heat exchanger : Double pipe and heat exchanger in abnormal condition

International Nuclear Information System (INIS)

Min, Ui Dong

1996-02-01

This book introduces theory and design of heat exchanger, which includes HTRI program, multiple tube heat exchanger external heating, theory of heat transfer, basis of design of heat exchanger, two-phase flow, condensation, boiling, material of heat exchanger, double pipe heat exchanger like hand calculation, heat exchanger in abnormal condition such as Jackets Vessel, and Coiled Vessel, design and summary of steam tracing.

Intra- and inter-shell Kondo effects in carbon nanotube quantum dots

Science.gov (United States)

Krychowski, Damian; Lipiński, Stanisław

2018-01-01

The linear response transport properties of carbon nanotube quantum dot in the strongly correlated regime are discussed. The finite-U mean field slave boson approach is used to study many-body effects. Magnetic field can rebuilt Kondo correlations, which are destroyed by the effect of spin-orbit interaction or valley mixing. Apart from the field induced revivals of SU(2) Kondo effects of different types: spin, valley or spin-valley, also more exotic phenomena appear, such as SU(3) Kondo effect. Threefold degeneracy occurs due to the effective intervalley exchange induced by short-range part of Coulomb interaction or due to the intershell mixing. In narrow gap nanotubes the full spin-orbital degeneracy might be recovered in the absence of magnetic field opening the condition for a formation of SU(4) Kondo resonance.

The Metaphysics of Economic Exchanges

Directory of Open Access Journals (Sweden)

Massin Olivier

2017-05-01

Full Text Available What are economic exchanges? The received view has it that exchanges are mutual transfers of goods motivated by inverse valuations thereof. As a corollary, the standard approach treats exchanges of services as a subspecies of exchanges of goods. We raise two objections against this standard approach. First, it is incomplete, as it fails to take into account, among other things, the offers and acceptances that lie at the core of even the simplest cases of exchanges. Second, it ultimately fails to generalize to exchanges of services, in which neither inverse preferences nor mutual transfers hold true. We propose an alternative definition of exchanges, which treats exchanges of goods as a special case of exchanges of services and which builds in offers and acceptances. According to this theory: (i The valuations motivating exchanges are propositional and convergent rather than objectual and inverse; (ii All exchanges of goods involve exchanges of services/actions, but not the reverse; (iii Offers and acceptances, together with the contractual obligations and claims they bring about, lie at the heart of all cases of exchange.

Marriage exchanges, seed exchanges, and the dynamics of manioc diversity.

Science.gov (United States)

Delêtre, Marc; McKey, Doyle B; Hodkinson, Trevor R

2011-11-08

The conservation of crop genetic resources requires understanding the different variables-cultural, social, and economic-that impinge on crop diversity. In small-scale farming systems, seed exchanges represent a key mechanism in the dynamics of crop genetic diversity, and analyzing the rules that structure social networks of seed exchange between farmer communities can help decipher patterns of crop genetic diversity. Using a combination of ethnobotanical and molecular genetic approaches, we investigated the relationships between regional patterns of manioc genetic diversity in Gabon and local networks of seed exchange. Spatially explicit Bayesian clustering methods showed that geographical discontinuities of manioc genetic diversity mirror major ethnolinguistic boundaries, with a southern matrilineal domain characterized by high levels of varietal diversity and a northern patrilineal domain characterized by low varietal diversity. Borrowing concepts from anthropology--kinship, bridewealth, and filiation--we analyzed the relationships between marriage exchanges and seed exchange networks in patrilineal and matrilineal societies. We demonstrate that, by defining marriage prohibitions, kinship systems structure social networks of exchange between farmer communities and influence the movement of seeds in metapopulations, shaping crop diversity at local and regional levels.

Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 6

International Nuclear Information System (INIS)

Plicka, J.; Stamberg, K.; Cabicar, J.; Gosman, A.

1986-01-01

The description of kinetics of ion exchange in ternary system was based upon three Nernst-Planck equations, each of them describing the particle diffusion flux of a given counterion as an independent process. For experimental verification, the strongly acidic cation exchanger OSTION KS 08 the shallow-bed technique, and 0.2 mol x dm -3 aqueous nitrate solutions were chosen. The kinetics of ion exchange in the system of cations Na + - Mg 2+ - UO 2 2+ was studied. The values of diffusion coefficients obtained by evaluating of kinetics of isotope exchange and binary ion exchange were used for calculation. The comparison of calculated exchange rate curves with the experimental ones was made. It was found that the exchanging counterions were affected by each other. (author)

Quantification of exchangeable and non-exchangeable organically bound tritium (OBT) in vegetation

International Nuclear Information System (INIS)

Kim, S.B.; Korolevych, V.

2013-01-01

The objective of this study is to quantify the relative amounts of exchangeable organically bound tritium (OBT) and non-exchangeable OBT in various vegetables. A garden plot at Perch Lake, where tritium levels are slightly elevated due to releases of tritium from a nearby nuclear waste management area and Chalk River Laboratories (CRL) operations, was used to cultivate a variety of vegetables. Five different kinds of vegetables (lettuce, cabbage, tomato, radish and beet) were studied. Exchangeable OBT behaves like tritium in tissue free water in living organisms and, based on past measurements, accounts for about 20% of the total tritium in dehydrated organic materials. In this study, the percentage of the exchangeable OBT was determined to range from 20% to 57% and was found to depend on the type of vegetables as well as the sequence of the plants exposure to HTO. -- Highlights: ► This study was to quantify the amount of exchangeable OBT compared to non-exchangeable OBT in vegetables. ► The percentage of exchangeable OBT varied between vegetable types and HTO exposure conditions. ► Exchangeable OBT varied from 20 to 36% in un-treated vegetables and from 30 to 57% in treated vegetables

Horizontal Curve Virtual Peer Exchange : an RSPCB Peer Exchange

Science.gov (United States)

2014-06-01

This report summarizes the Horizontal Curve Virtual Peer Exchange sponsored by the Federal Highway Administration (FHWA) Office of Safetys Roadway Safety Professional Capacity Building Program on June 17, 2014. This virtual peer exchange was the f...

Interest Rate Rules, Exchange Market Pressure, and Successful Exchange Rate Management

NARCIS (Netherlands)

Klaassen, F.; Mavromatis, K.

2016-01-01

Central banks with an exchange rate objective set the interest rate in response to what they call ''pressure.'' Instead, existing interest rate rules rely on the exchange rate minus its target. To stay closer to actual policy, we introduce a rule that uses exchange market pressure (EMP), the

First-principles investigation of quantum transport through an endohedral N@C60 in the Coulomb blockade regime.

Science.gov (United States)

Yu, Zhizhou; Chen, Jian; Zhang, Lei; Wang, Jian

2013-12-11

We report an investigation of Coulomb blockade transport through an endohedral N@C60 weakly coupled with aluminum leads, employing the first-principles method combined with the Keldysh non-equilibrium Green's function derived from the equation of motion beyond the Hartree-Fock approximation. The differential conductance characteristics of the molecular device are calculated within the Coulomb blockade regime, which shows the Coulomb diamond as observed experimentally. When the gate voltage is less than that of the degeneracy point, there are two peaks in the differential conductance with an excited state induced by the change of the exchange interaction between the spin of C60 and the encapsulated nitrogen atom due to the transition from N@C(1-)(60) to N@C(2-)(60), while for a gate voltage larger than that of the degeneracy point, no excited state is available due to the quenching of exchange energy. As a result, there is only one Coulomb blockade peak in the differential conductance from the electron tunneling through the highest energy level below the Fermi level. Our first-principles results are in good agreement with experimental data obtained by an endohedral N@C60 molecular device.

Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.

Science.gov (United States)

Amin, M R

2015-09-01

Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented.

Ab-initio calculations of Co-based diluted magnetic semiconductors Cd 1-xCoxX (X=S, Se, Te)

KAUST Repository

Saeed, Yasir

2010-10-01

Ab-initio calculations are performed to investigate the structural, electronic and magnetic properties of spin-polarized diluted magnetic semiconductors composed of IIVI compounds Cd1-xCoxX (X=S, Se, Te) at x=0.25. From the calculated results of band structure and density of states, the half-metallic character and stability of ferromagnetic state for Cd1-xCoxS, Cd1-xCoxSe and Cd 1-xCoxTe alloys are determined. It is found that the tetrahedral crystal field gives rise to triple degeneracy t2g and double degeneracy eg. Furthermore, we predict the values of spin-exchange splitting energies Δx(d) and Δ x(p-d) and exchange constants N0α and N 0β produced by the Co 3d states. Calculated total magnetic moments and the robustness of half-metallicity of Cd1-xCo xX (X=S, Se, Te) with respect to the variation in lattice parameters are also discussed. We also extend our calculations to x=0.50, 0.75 for S compounds in order to observe the change due to increase in Co. © 2010 Elsevier B.V.

Standardizing exchange formats

International Nuclear Information System (INIS)

Lemmel, H.D.; Schmidt, J.J.

1992-01-01

An international network of co-operating data centres is described who maintain identical data bases which are simultaneously updated by an agreed data exchange procedure. The agreement covers ''data exchange formats'' which are compatible to the centres' internal data storage and retrieval systems which remain different, optimized at each centre to the available computer facilities and to the needs of the data users. Essential condition for the data exchange is an agreement on common procedures for the data exchange is an agreement on common procedures for the data compilation, including critical data analysis and validation. The systems described (''EXFOR'', ''ENDF'', ''CINDA'') are used for ''nuclear reaction data'', but the principles used for data compilation and exchange should be valid also for other data types. (author). 24 refs, 4 figs

Magnetic stability in exchange-spring and exchange bias systems after multiple switching cycles.

Energy Technology Data Exchange (ETDEWEB)

Jiang, J. S.; Inomata, A.; You, C.-Y.; Pearson, J. E.; Bader, S. D.

2001-06-01

We have studied the magnetic stability in exchange bias and exchange spring systems prepared via epitaxial sputter deposition. The two interfacial exchange coupled systems, Fe/Cr(211) double superlattices consisting of a ferromagnetic and an antiferromagnetic Fe/Cr superlattice that are exchange coupled through a Cr spacer, and Sin-Co/Fe exchange-spring bilayer structures with ferromagnetically coupled hard Sin-Co layer and soft Fe layer, were epitaxially grown on suitably prepared Cr buffer layers to give rise to different microstructure and magnetic anisotropy. The magnetic stability was investigated using the magneto-optic Kerr effect during repeated reversal of the soft layer magnetization by field cycling up to 10{sup 7} times. For uniaxial Fe/Cr exchange biased double superlattices and exchange spring bilayers with uniaxial Sin-Co, small but rapid initial decay in the exchange bias field HE and in the remanent magnetization is observed. However, the exchange spring bilayers with biaxial and random in-plane anisotropy in the Sin-Co layer shows gradual decay in H{sub E} and without large reduction of the magnetization. The different decay behaviors are attributed to the different microstructure and spin configuration of the pinning layers.

The effects of real exchange rate misalignment and real exchange volatility on exports

OpenAIRE

Diallo, Ibrahima Amadou

2011-01-01

This paper uses panel data cointegration techniques to study the impacts of real exchange rate misalignment and real exchange rate volatility on total exports for a panel of 42 developing countries from 1975 to 2004. The results show that both real exchange rate misalignment and real exchange rate volatility affect negatively exports. The results also illustrate that real exchange rate volatility is more harmful to exports than misalignment. These outcomes are corroborated by estimations on s...

Impulse Response of the Exchange Rate Volatility to a Foreign Exchange Intervention Shock

OpenAIRE

Hoshikawa, Takeshi

2009-01-01

This paper uses Lin's technique (1997) to report on the impulse response function analysis that traces the dynamics of exchange rate volatility from innovations in Japanese foreign exchange intervention. Using a multivariate GARCH model, we employed a volatility impulse response function based on Lin (1997) to detect the impulse response of exchange rate volatility on a one-unit foreign exchange intervention shock. The main findings of t his paper are as follows: (1) a foreign exchange inter...

Two-dimensional exchange and nutation exchange nuclear quadrupole resonance spectroscopy

International Nuclear Information System (INIS)

Mackowiak, M.; Sinyavsky, N.; Velikite, N.; Nikolaev, D.

2002-01-01

A theoretical treatment of the 2D exchange NQR pulse sequence is presented and applied to a quantitative study of exchange processes in molecular crystals. It takes into account the off-resonance irradiation, which critically influences the spin dynamics. The response to the three-pulse sequence of a system of spins I=3/2 in zero applied field, experiencing electric quadrupole couplings, is analysed. The mixing dynamics by exchange and the expected cross-peak intensities as a function of the frequency offset have been derived. The theory is illustrated by a study of the optimization procedure, which is of crucial importance for the detection of the cross- and diagonal-peaks in a 2D-exchange spectrum. The systems investigated are hexachloroethane and tetrachloroethylene. They show threefold and twofold reorientational jumps about the carbon-carbon axis, respectively. A new method of direct determination of rotational angles based on two-dimensional nutation exchange NQR spectroscopy is proposed. The method involves the detection of exchange processes through NQR nutation spectra recorded after the mixing interval. The response of a system of spins I=3/2 to the three-pulse sequence with increasing pulse widths is analyzed. It is shown that the 2D-nutation exchange NQR spectrum exhibits characteristic ridges, which manifest the motional mechanism in a model-independent fashion. The angles through which the molecule rotates can be read directly from elliptical ridges in the 2D spectrum, which are also sensitive to the asymmetry parameter of the electric field gradient tensor. (orig.)

Noninvasive mapping of water diffusional exchange in the human brain using filter-exchange imaging.

Science.gov (United States)

Nilsson, Markus; Lätt, Jimmy; van Westen, Danielle; Brockstedt, Sara; Lasič, Samo; Ståhlberg, Freddy; Topgaard, Daniel

2013-06-01

We present the first in vivo application of the filter-exchange imaging protocol for diffusion MRI. The protocol allows noninvasive mapping of the rate of water exchange between microenvironments with different self-diffusivities, such as the intracellular and extracellular spaces in tissue. Since diffusional water exchange across the cell membrane is a fundamental process in human physiology and pathophysiology, clinically feasible and noninvasive imaging of the water exchange rate would offer new means to diagnose disease and monitor treatment response in conditions such as cancer and edema. The in vivo use of filter-exchange imaging was demonstrated by studying the brain of five healthy volunteers and one intracranial tumor (meningioma). Apparent exchange rates in white matter range from 0.8±0.08 s(-1) in the internal capsule, to 1.6±0.11 s(-1) for frontal white matter, indicating that low values are associated with high myelination. Solid tumor displayed values of up to 2.9±0.8 s(-1). In white matter, the apparent exchange rate values suggest intra-axonal exchange times in the order of seconds, confirming the slow exchange assumption in the analysis of diffusion MRI data. We propose that filter-exchange imaging could be used clinically to map the water exchange rate in pathologies. Filter-exchange imaging may also be valuable for evaluating novel therapies targeting the function of aquaporins. Copyright © 2012 Wiley Periodicals, Inc.

Optimization of Heat Exchangers

International Nuclear Information System (INIS)

Catton, Ivan

2010-01-01

The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics (pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger design.

Chemical exchange rotation transfer imaging of intermediate-exchanging amines at 2 ppm.

Science.gov (United States)

Zu, Zhongliang; Louie, Elizabeth A; Lin, Eugene C; Jiang, Xiaoyu; Does, Mark D; Gore, John C; Gochberg, Daniel F

2017-10-01

Chemical exchange saturation transfer (CEST) imaging of amine protons exchanging at intermediate rates and whose chemical shift is around 2 ppm may provide a means of mapping creatine. However, the quantification of this effect may be compromised by the influence of overlapping CEST signals from fast-exchanging amines and hydroxyls. We aimed to investigate the exchange rate filtering effect of a variation of CEST, named chemical exchange rotation transfer (CERT), as a means of isolating creatine contributions at around 2 ppm from other overlapping signals. Simulations were performed to study the filtering effects of CERT for the selection of transfer effects from protons of specific exchange rates. Control samples containing the main metabolites in brain, bovine serum albumin (BSA) and egg white albumen (EWA) at their physiological concentrations and pH were used to study the ability of CERT to isolate molecules with amines at 2 ppm that exchange at intermediate rates, and corresponding methods were used for in vivo rat brain imaging. Simulations showed that exchange rate filtering can be combined with conventional filtering based on chemical shift. Studies on samples showed that signal contributions from creatine can be separated from those of other metabolites using this combined filter, but contributions from protein amines may still be significant. This exchange filtering can also be used for in vivo imaging. CERT provides more specific quantification of amines at 2 ppm that exchange at intermediate rates compared with conventional CEST imaging. Copyright © 2017 John Wiley & Sons, Ltd.

Ion exchange kinetics of alkaline earths on Zr(IV) arsenosilicate cation exchanger

International Nuclear Information System (INIS)

Varshney, K.G.; Agrawal, S.; Varshney, K.

1984-01-01

A new approach based on the Nernst-Planck equations was applied to study the ion exchange kinetics for the exchange reactions of Mg(II), Ca(II), Sr(II) and Ba(II) with H + -ions at various temperatures on the zirconium(IV) arsenosilicate phase. Under the conditions of particle diffusion, the rate of exchange was found to be independent of the metal ion concentration at and above 0.1 M in aqueous medium. Energy and entropy of activation were determined and found to vary linearly with the ionic radii and mobilities of alkaline earths, a unique feature observed for an inorganic ion exchanger. The results are useful for predicting the ion exchange processes occurring on the surface of an inorganic material of the type studied. (author)

Differential multiple quantum relaxation caused by chemical exchange outside the fast exchange limit

International Nuclear Information System (INIS)

Wang Chunyu; Palmer, Arthur G.

2002-01-01

Differential relaxation of multiple quantum coherences is a signature for chemical exchange processes in proteins. Previous analyses of experimental data have used theoretical descriptions applicable only in the limit of fast exchange. Theoretical expressions for differential relaxation rate constants that are accurate outside fast exchange are presented for two-spin-system subject to two-site chemical exchange. The theoretical expressions are validated using experimental results for 15 N- 1 H relaxation in basic pancreatic trypsin inhibitor. The new theoretical expression is valuable for identification and characterization of exchange processes in proteins using differential relaxation of multiple quantum coherences

Outlook for ion exchange

International Nuclear Information System (INIS)

Kunin, R.

1977-01-01

This paper presents the history and theory of ion exchange technology and discusses the usefulness of ion exchange resins which found broad applications in chemical operations. It is demonstrated that the theory of ion exchange technology seems to be moving away from the physical chemist back to the polymer chemist where it started originally. This but confronted the polymer chemists with some knotty problems. It is pointed out that one has still to learn how to use ion exchange materials as efficiently as possible in terms of the waste load that is being pumped into the environment. It is interesting to note that, whereas ion exchange is used for abating pollution, it is also a polluter. One must learn how to use ion exchange as an antipollution device, and at the same time minimize its polluting properties

Longitudinal exchange: an alternative strategy towards quantification of dynamics parameters in ZZ exchange spectroscopy

International Nuclear Information System (INIS)

Kloiber, Karin; Spitzer, Romana; Grutsch, Sarina; Kreutz, Christoph; Tollinger, Martin

2011-01-01

Longitudinal exchange experiments facilitate the quantification of the rates of interconversion between the exchanging species, along with their longitudinal relaxation rates, by analyzing the time-dependence of direct correlation and exchange cross peaks. Here we present a simple and robust alternative to this strategy, which is based on the combination of two complementary experiments, one with and one without resolving exchange cross peaks. We show that by combining the two data sets systematic errors that are caused by differential line-broadening of the exchanging species are avoided and reliable quantification of kinetic and relaxation parameters in the presence of additional conformational exchange on the ms–μs time scale is possible. The strategy is applied to a bistable DNA oligomer that displays different line-broadening in the two exchanging species.

Analytical applications of ion exchangers

CERN Document Server

Inczédy, J

1966-01-01

Analytical Applications of Ion Exchangers presents the laboratory use of ion-exchange resins. This book discusses the development in the analytical application of ion exchangers. Organized into 10 chapters, this book begins with an overview of the history and significance of ion exchangers for technical purposes. This text then describes the properties of ion exchangers, which are large molecular water-insoluble polyelectrolytes having a cross-linked structure that contains ionic groups. Other chapters consider the theories concerning the operation of ion-exchange resins and investigate th

Social dilemmas as exchange dilemmas

NARCIS (Netherlands)

Dijkstra, Jacob; van Assen, Marcel A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Building on focusing and

Social dilemmas as exchange dilemmas

NARCIS (Netherlands)

Dijkstra, J.; van Assen, M.A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Bulding on focusing and

Update heat exchanger designing principles

International Nuclear Information System (INIS)

Lipets, A.U.; Yampol'skij, A.E.

1985-01-01

Update heat exchanger design principles are analysed. Different coolant pattern in a heat exchanger are considered. It is suggested to rationally organize flow rates irregularity in it. Applying on heat exchanger designing measures on using really existing temperature and flow rate irregularities will permit to improve heat exchanger efficiency. It is expedient in some cases to artificially produce irregularities. In this connection some heat exchanger design principles must be reviewed now

Degeneracy relations in QCD and the equivalence of two systematic all-orders methods for setting the renormalization scale

Directory of Open Access Journals (Sweden)

Huan-Yu Bi

2015-09-01

Full Text Available The Principle of Maximum Conformality (PMC eliminates QCD renormalization scale-setting uncertainties using fundamental renormalization group methods. The resulting scale-fixed pQCD predictions are independent of the choice of renormalization scheme and show rapid convergence. The coefficients of the scale-fixed couplings are identical to the corresponding conformal series with zero β-function. Two all-orders methods for systematically implementing the PMC-scale setting procedure for existing high order calculations are discussed in this article. One implementation is based on the PMC-BLM correspondence (PMC-I; the other, more recent, method (PMC-II uses the Rδ-scheme, a systematic generalization of the minimal subtraction renormalization scheme. Both approaches satisfy all of the principles of the renormalization group and lead to scale-fixed and scheme-independent predictions at each finite order. In this work, we show that PMC-I and PMC-II scale-setting methods are in practice equivalent to each other. We illustrate this equivalence for the four-loop calculations of the annihilation ratio Re+e− and the Higgs partial width Γ(H→bb¯. Both methods lead to the same resummed (‘conformal’ series up to all orders. The small scale differences between the two approaches are reduced as additional renormalization group {βi}-terms in the pQCD expansion are taken into account. We also show that special degeneracy relations, which underly the equivalence of the two PMC approaches and the resulting conformal features of the pQCD series, are in fact general properties of non-Abelian gauge theory.

Compact heat exchanger for power plants

International Nuclear Information System (INIS)

Kinnunen, L.

2001-01-01

Vahterus Oy, located at Kalanti, has manufactured heat exchangers since the beginning of 1990s. About 90% of the equipment produced are exported. In the PSHE (Plate and Shell) solution of the Vahterus heat exchanger the heat is transferred by round plated welded to form a compact package, which is assembled into a cylindrical steel casing. The heat exchanger contains no gaskets or soldered joints, which eliminates the leak risks. Traditional heat exchanges are usually operated at higher temperatures and pressures, but the heat transfer capacities of them are lower. Plate heat exchangers, on the other hand, are efficient, but the application range of them is narrow. Additionally, the rubber gasket of the heat exchange plates, sealing the joints of the heat exchanging plates, does not stand high pressures or temperatures, or corroding fluids. The new welded plate heat exchanger combine the pressure and temperature resistance of tube heat exchangers and the high heat exchange capacity of plate heat exchangers. The new corrosion resisting heat exchanger can be applied for especially hard conditions. The operating temperature range of the PSHE heat exchanger is - 200 - 900 deg C. The pressure resistance is as high as 100 bar. The space requirement of PSHE is only one tenth of the space requirement of traditional tube heat exchangers. Adjusting the number of heat exchanging plates can change the capacity of the heat exchanger. Power range of the heat exchanger can be as high as 80 MW. Due to the corrosion preventive construction and the small dimension the PSHE heat exchanger can be applied for refrigerators using ammonia as refrigerant. These kinds of new Vahterus heat exchangers are in use in 60 countries in more than 2000 refrigerators

Exchanging Description Logic Knowledge Bases

NARCIS (Netherlands)

Arenas, M.; Botoeva, E.; Calvanese, D.; Ryzhikov, V.; Sherkhonov, E.

2012-01-01

In this paper, we study the problem of exchanging knowledge between a source and a target knowledge base (KB), connected through mappings. Differently from the traditional database exchange setting, which considers only the exchange of data, we are interested in exchanging implicit knowledge. As

Rastros, rostros y voces del racismo institucional en Cartagena: Un acercamiento a partir del debate de la “degeneración de las razas”, 1910-1930

Directory of Open Access Journals (Sweden)

Francisco Javier Florez Bolivar

2013-11-01

Full Text Available Este artículo analiza la apropiación que hicieron una serie de intelectuales colombianos sobre el  racial que distintos autores del mundo europeo y estadounidense, ampliamente inspirados  las ideas del racismo científico, consolidaron en el transito en el siglo XIX al XX. Tomando como base  debate conocido como la degeneración de las razas, intento sustentar la idea de que los discursos que  torno a los sectores negros y mulatos se construyeron en los mismos tuvieron unos  reales  concretos que derivaron en disposiciones  ampliamente utilizadas en contextos  Cartagena, hasta el punto de incidir en las practicas sociales de los individuos al radicalizar las  relaciones socio-raciales que históricamente han caracterizado esta sociedad, y con ello se  una suerte de racismo institucional entre los años de 1910 y 1930.

Social dilemmas as exchange dilemmas

OpenAIRE

Dijkstra, J.; van Assen, M.A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Bulding on focusing and framing research we predict that defection is omnipresent in exchange dilemmas, which is corroborated in to very different experiments. Our results suggest that the fundamental problem of cooperation in...

Apparatus and process for deuterium exchange

International Nuclear Information System (INIS)

Ergenc, M.S.

1976-01-01

The deuterium exchange plant is combined with an absorption refrigeration plant in order to improve the exchange process and to produce refrigeration. The refrigeration plant has a throttling means for expanding and cooling a portion of the liquid exchange medium separated in the exchange plant as well as an evaporator, in which the said liquid exchange medium is brought into heat exchange with a cold consumer device, absorption means for forming a solution of the used exchange medium and fresh water and a pump for pumping the solution into the exchange plant

Exchange, x-ray and IR spectral behaviour of lanthanum and praseodymium exchanged zeolite X

International Nuclear Information System (INIS)

Das, D.; Upreti, M.C.

1995-01-01

Exchange behaviour of lanthanum and praseodymium ions in zeolite X involves three steps: preferential exchange, intrazeolitic exchange and irreversible exchange. At room temperature , higher exchange has been observed with La(III) than with Pr(III) which is attributed to the smaller hydrosphere of lanthanum than praseodymium. IR spectra of these zeolites in KBr pellets show a shift in the major Si-O stretching vibration of 972 cm -1 to higher frequencies. Their x-ray diffraction patterns remain unchanged except a large decrease of the line intensities caused by the absorption of x-rays by heavy La(III) and Pr(III) ions. The present study reports the preparation and physicochemical properties of lanthanum and praseodymium exchanged zeolite X. (author). 12 refs., 3 figs., 3 tabs

Isotopically exchangeable phosphorus

International Nuclear Information System (INIS)

Barbaro, N.O.

1984-01-01

A critique revision of isotope dilution is presented. The concepts and use of exchangeable phosphorus, the phosphate adsorption, the kinetics of isotopic exchange and the equilibrium time in soils are discussed. (M.A.C.) [pt

Is a more stable exchange rate associated with reduced exchange rate pass-through?

OpenAIRE

Mark J. Holmes

2007-01-01

Pass-through from the nominal effective exchange rate to import prices is modelled within a regime-switching environment. Evidence suggests that exchange rate pass through can be characterised as regime-specific where the probability of switching between regimes is influenced by the extent of exchange rate volatility.

Exchange of Information in Tax Matters

Directory of Open Access Journals (Sweden)

Paweł Szwajdler

2017-01-01

Full Text Available The main aim of this paper is to present issues related to exchange of tax information. The author focuses on models of exchange of information and boundaries of obligations in reference to above-mentioned problems. Automatic exchange of information, spontaneous exchange of information and exchange of information on request are analysed in this work on the base of OECD Convention on Mutual Administrative Assistance in Tax Matters, Council Directive 2011/16 and OECD Model Agreement on Exchange of Information in Tax Matters. In the summary, it was showed that the most efficient method of exchange of tax information is automatic exchange of information. Furthermore, it was stated that exchange on request can be related to negative phenomenon such as fishing expedition. Spontaneous exchange of information is thought to play only supportive role.  The author also considers that boundaries of exchange of information in tax matters were regulated so as to protect jeopardised raison d’ État.

Bretton Woods Fixed Exchange Rate System versus Floating Exchange Rate System

OpenAIRE

Geza, Paula; Giurca Vasilescu, Laura

2011-01-01

One of the most important issues of monetary policy is to find out whether the state should intervene among the exchange rates, taking into account the fact that changes in the exchange rates represent a significant transmission channel of the effects generated by the monetary policy. Taking into consideration the failure of fixed exchange rate regimes and the recent improvement of financial markets, the return in the near future to such a regime – as for example the Bretton Woods system –...

Hydrogen exchange

DEFF Research Database (Denmark)

Jensen, Pernille Foged; Rand, Kasper Dyrberg

2016-01-01

Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

Anion exchange membrane

Science.gov (United States)

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

Radial flow heat exchanger

Science.gov (United States)

Valenzuela, Javier

2001-01-01

A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

Exchange Studies as Actor-Networks: Following Korean Exchange Students in Swedish Higher Education

Science.gov (United States)

Ahn, Song-ee

2011-01-01

This article explores how Korean exchange students organized their studies during exchange programs in Swedish higher education. For most students, the programs became a disordered period in relation to their education. The value of exchange studies seems mainly to be extra-curricular. Drawing upon actor network theory, the article argues that the…

Imaging of endogenous exchangeable proton signals in the human brain using frequency labeled exchange transfer imaging.

Science.gov (United States)

Yadav, Nirbhay N; Jones, Craig K; Hua, Jun; Xu, Jiadi; van Zijl, Peter C M

2013-04-01

To image endogenous exchangeable proton signals in the human brain using a recently reported method called frequency labeled exchange transfer (FLEX) MRI. As opposed to labeling exchangeable protons using saturation (i.e., chemical exchange saturation transfer, or CEST), FLEX labels exchangeable protons with their chemical shift evolution. The use of short high-power frequency pulses allows more efficient labeling of rapidly exchanging protons, while time domain acquisition allows removal of contamination from semi-solid magnetization transfer effects. FLEX-based exchangeable proton signals were detected in human brain over the 1-5 ppm frequency range from water. Conventional magnetization transfer contrast and the bulk water signal did not interfere in the FLEX spectrum. The information content of these signals differed from in vivo CEST data in that the average exchange rate of these signals was 350-400 s(-1) , much faster than the amide signal usually detected using direct saturation (∼30 s(-1) ). Similarly, fast exchanging protons could be detected in egg white in the same frequency range where amide and amine protons of mobile proteins and peptides are known to resonate. FLEX MRI in the human brain preferentially detects more rapidly exchanging amide/amine protons compared to traditional CEST experiments, thereby changing the information content of the exchangeable proton spectrum. This has the potential to open up different types of endogenous applications as well as more easy detection of rapidly exchanging protons in diaCEST agents or fast exchanging units such as water molecules in paracest agents without interference of conventional magnetization transfer contrast. Copyright © 2013 Wiley Periodicals, Inc.

Hibernation and gas exchange.

Science.gov (United States)

Milsom, William K; Jackson, Donald C

2011-01-01

Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature. © 2011 American Physiological Society.

Degeneración cerebelosa subaguda paraneoplásica: caso clínico

Directory of Open Access Journals (Sweden)

Natalia Castañeda Curto

2018-05-01

Full Text Available Introducción y objetivo: La degeneración cerebelosa paraneoplásica (DCP es un síndrome poco frecuente y de difícil diagnóstico. Suele presentarse meses o años antes de la aparición de una neoplasia y, menos frecuentemente, ocurre en pacientes con una neoplasia conocida o como forma de recidiva. Nuestro objetivo es describir un caso clínico diagnosticado en nuestra comunidad.Material y Método: Mujer de 49 años, exfumadora de 23 paq/año que a principios de año acude a Urgencias por inestabilidad progresiva estando previamente asintomática, por lo que es derivada a Neurología y Otorrinolaringología.Resultados: En la exploración ORL presenta otoscopia y audiometría normales. Nistagmo de dirección cambiante. VVOR: ojos de muñeca V-HIT con ganancias normales, no sacadas de refijación.Tras la realización de pruebas complementarias se objetiva un nódulo pulmonar de 9mm y conglomerado adenopatico mediastínico. Ante la sospecha de neoplasia se realiza biopsia transbronquial con resultado de carcinoma microcítico. En inmunología se detectaron anti CV2 positivo, estableciéndose el diagnóstico de ataxia cerebelosa subaguda paraneoplásica.Conclusiones: La evolución de este síndrome provoca pérdida neuronal irreversible siendo, por tanto, el diagnóstico precoz y el tratamiento fundamentales en el pronóstico.  Introduction and objective: Paraneoplastic cerebellar degeneration is a rare syndrome and it is difficult to diagnose. It usually appears months or years before the onset of a malignant neoplasm and, less frequently, occurs in patients with a known neoplasm or as a form of recurrence. Our objective is to describe a clinical case diagnosed in our community.Material and Method: A 49-year-old woman, an ex-smoker of 23 pack/year who, at the beginning of the year, went to the Emergency Department due to progressive instability. She was previously asymptomatic and was referred to Neurology and Otolaryngology.Results: In the

Mastering Microsoft Exchange Server 2010

CERN Document Server

McBee, Jim

2010-01-01

A top-selling guide to Exchange Server-now fully updated for Exchange Server 2010. Keep your Microsoft messaging system up to date and protected with the very newest version, Exchange Server 2010, and this comprehensive guide. Whether you're upgrading from Exchange Server 2007 SP1 or earlier, installing for the first time, or migrating from another system, this step-by-step guide provides the hands-on instruction, practical application, and real-world advice you need.: Explains Microsoft Exchange Server 2010, the latest release of Microsoft's messaging system that protects against spam and vir

Study of ion exchange equilibrium and determination of heat of ion exchange by ion chromatography

International Nuclear Information System (INIS)

Liu Kailu; Yang Wenying

1996-01-01

Ion chromatography using pellicularia ion exchange resins and dilute solution can be devoted to the study of ion exchange thermodynamics and kinetics. Ion exchange equilibrium equation was obtained, and examined by the experiments. Based on ion exchange equilibrium, the influence of eluent concentration and resin capacity on adjusted retention volumes was examined. The effect of temperature on adjusted retention volumes was investigated and heats of ion exchange of seven anions were determined by ion chromatography. The interaction between anions and skeleton structure of resins were observed

Progress in liquid ion exchangers

International Nuclear Information System (INIS)

Nakagawa, Genkichi

1974-01-01

Review is made on the extraction with anion exchangers and the extraction with liquid cation exchangers. On the former, explanation is made on the extraction of acids, the relation between anion exchange and the extraction of metals, the composition of the metallic complexes that are extracted, and the application of the extraction with anion exchangers to analytical chemistry. On the latter, explanation is made on the extraction of metals and its application to analytical chemistry. The extraction with liquid ion exchangers is suitable for the operation in chromatography, because the distribution of extracting agents into aqueous phase is small, and extraction equilibrium is quickly reached, usually within 1 to several minutes. The separation by means of anion exchangers is usually made from hydrochloric acid solution. For example, Brinkman et al. determined Rf values for more than 50 elements by thin layer chromatography. Tables are given for showing the structure of the liquid ion exchangers and the polymerized state of various amines. (Mori, K.)

Road Safety Peer Exchange for Tribal Governments : an RSPCB Peer Exchange

Science.gov (United States)

2014-12-01

This report provides a summary of the proceedings of the Road Safety Peer Exchange for Tribal : Governments held in Albuquerque, New Mexico on December 9th and 10th, 2014. The peer exchange : brought together safety practitioners from across the Unit...

Influence of electron correlation and degeneracy on the Fukui matrix and extension of frontier molecular orbital theory to correlated quantum chemical methods.

Science.gov (United States)

Bultinck, Patrick; Van Neck, Dimitri; Acke, Guillaume; Ayers, Paul W

2012-02-21

The Fukui function is considered as the diagonal element of the Fukui matrix in position space, where the Fukui matrix is the derivative of the one particle density matrix (1DM) with respect to the number of electrons. Diagonalization of the Fukui matrix, expressed in an orthogonal orbital basis, explains why regions in space with negative Fukui functions exist. Using a test set of molecules, electron correlation is found to have a remarkable effect on the eigenvalues of the Fukui matrix. The Fukui matrices at the independent electron model level are mathematically proven to always have an eigenvalue equal to exactly unity while the rest of the eigenvalues possibly differ from zero but sum to zero. The loss of idempotency of the 1DM at correlated levels of theory causes the loss of these properties. The influence of electron correlation is examined in detail and the frontier molecular orbital concept is extended to correlated levels of theory by defining it as the eigenvector of the Fukui matrix with the largest eigenvalue. The effect of degeneracy on the Fukui matrix is examined in detail, revealing that this is another way by which the unity eigenvalue and perfect pairing of eigenvalues can disappear.

Exchange of Information in Tax Matters

OpenAIRE

Paweł Szwajdler

2017-01-01

The main aim of this paper is to present issues related to exchange of tax information. The author focuses on models of exchange of information and boundaries of obligations in reference to above-mentioned problems. Automatic exchange of information, spontaneous exchange of information and exchange of information on request are analysed in this work on the base of OECD Convention on Mutual Administrative Assistance in Tax Matters, Council Directive 2011/16 and OECD Model Agreement on Exchange...

3.5 Radiation stability of ion exchangers

International Nuclear Information System (INIS)

Marhol, M.

1976-01-01

The main knowledge is summed up of the radiation stability of ion exchangers. No basic changes occur in inorganic ion exchangers with the exception of the exchange capacity at doses of up to 10 9 rad. This also applies to coal-based ion exchangers. Tables are given showing the changes in specific volume, exchange capacity and weight of different types of organic ion exchangers in dependence on the radiation dose. The effects are discussed of the structure of organic cation and anion exchangers, polymeric strong basic anion exchangers, polycondensate anion exchangers and ion exchange membranes on their radiation stability. General experimental procedures are given for laboratory tests of the radiation stability of exchangers. (L.K.)

Local Road Safety Peer Exchange - Region 4 : An RSPCB Peer Exchange

Science.gov (United States)

2013-03-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Atlanta, Georgia on March 6th and 7th, 2013. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 4 Local Te...

Local Road Safety Peer Exchange - Region 7 : An RSPCB Peer Exchange

Science.gov (United States)

2012-05-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Denver, Colorado from May 31 to June 1, 2012. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 7 Local a...

Local Road Safety Peer Exchange - Region 1 : An RSPCB Peer Exchange

Science.gov (United States)

2012-10-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Piscataway, New Jersey October 10th and 11th, 2012. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 1 L...

Synthetic inorganic ion-exchange materials

International Nuclear Information System (INIS)

Abe, M.

1979-01-01

Exchange isotherms for hydrogen ion/alkali metal ions have been measured at 20 and 40 0 C, with a solution ionic strength of 0.1, in crystalline antimonic(V) acid as a cation-exchanger. The isotherms showed S-shaped curves for the systems of H + /Na + , H + /K + , H + /Rb + and H + /Cs + , but not for H + /Li + exchange. The selectivity coefficients (logarithm scale) vs equivalent fraction of alkali metal ions in the exchanger give linear functions for all systems studied. The selectivity sequences are shown. Overall and hypothetical (zero loading) thermodynamic equilibrium constants were evaluated for these ion-exchange reactions. (author)

Microsoft Exchange 2013 cookbook

CERN Document Server

Van Horenbeeck, Michael

2013-01-01

This book is a practical, hands-on guide that provides the reader with a number of clear, step-by-step exercises.""Microsoft Exchange 2013 Cookbook"" is targeted at network administrators who deal with the Exchange server in their day-to-day jobs. It assumes you have some practical experience with previous versions of Exchange (although this is not a requirement), without being a subject matter expert.

Choice of exchange rate regimes for African countries: Fixed or Flexible Exchange rate regimes?

OpenAIRE

Simwaka, Kisu

2010-01-01

The choice of an appropriate exchange rate regime has been a subject of ongoing debate in international economics. The majority of African countries are small open economies and thus where the choice of the exchange rate regime is an important policy issue. Aside from factors such as interest rates and inflation, the exchange rate is one of the most important determinants of a country’s relative level of economic health. For this reason, exchange rates are among the most watched analyzed and ...

Innovative heat exchangers

CERN Document Server

Scholl, Stephan

2018-01-01

This accessible book presents unconventional technologies in heat exchanger design that have the capacity to provide solutions to major concerns within the process and power-generating industries. Demonstrating the advantages and limits of these innovative heat exchangers, it also discusses micro- and nanostructure surfaces and micro-scale equipment, and introduces pillow-plate, helical and expanded metal baffle concepts. It offers step-by-step worked examples, which provide instructions for developing an initial configuration and are supported by clear, detailed drawings and pictures. Various types of heat exchangers are available, and they are widely used in all fields of industry for cooling or heating purposes, including in combustion engines. The market in 2012 was estimated to be U$ 42.7 billion and the global demand for heat exchangers is experiencing an annual growth of about 7.8 %. The market value is expected to reach U$ 57.9 billion in 2016, and approach U$ 78.16 billion in 2020. Providing a valua...

Upright heat exchanger

International Nuclear Information System (INIS)

Martoch, J.; Kugler, V.; Krizek, V.; Strmiska, F.

1988-01-01

The claimed heat exchanger is characteristic by the condensate level being maintained directly in the exchanger while preserving the so-called ''dry'' tube plate. This makes it unnecessary to build another pressure vessel into the circuit. The design of the heat exchanger allows access to both tube plates, which facilitates any repair. Another advantage is the possibility of accelerating the indication of leakage from the space of the second operating medium which is given by opening the drainage pipes of the lower bundle into the collar space and from there through to the indication pipe. The exchanger is especially suitable for deployment in the circuits of nuclear power plants where the second operating medium will be hot water of considerably lower purity than is that of the condensate. A rapid display of leakage can prevent any long-term penetration of this water into the condensate, which would result in worsening water quality in the entire secondary circuit of the nuclear power plant. (J.B.). 1 fig

Australian Universities' Strategic Goals of Student Exchange and Participation Rates in Outbound Exchange Programmes

Science.gov (United States)

Daly, Amanda; Barker, Michelle

2010-01-01

International student exchange programmes are acknowledged as one aspect of a broader suite of internationalisation strategies aimed at enhancing students' intercultural understanding and competence. The decision to participate in an exchange programme is dependent on both individual and contextual factors such as student exchange policies and…

78 FR 46622 - Application of Topaz Exchange, LLC for Registration as a National Securities Exchange; Findings...

Science.gov (United States)

2013-08-01

... Exchange, LLC for Registration as a National Securities Exchange; Findings, Opinion, and Order of the... Registration as a National Securities Exchange (``Form 1 Application'') \\1\\ under Section 6 of the Securities... substantive, are consistent with the existing rules of other registered national securities exchanges, or are...

Increased CEST specificity for amide and fast-exchanging amine protons using exchange-dependent relaxation rate.

Science.gov (United States)

Zhang, Xiao-Yong; Wang, Feng; Xu, Junzhong; Gochberg, Daniel F; Gore, John C; Zu, Zhongliang

2018-02-01

Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast-exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi-solid non-specific magnetization transfer (MT), the influence of water relaxation times (T 1w ) and nearby overlapping CEST signals. Although several editing techniques have been developed to increase the specificity by removing DS, semi-solid MT and T 1w influences, it is still challenging to remove overlapping CEST signals from different exchanging sites. For instance, the amide proton transfer (APT) signal could be contaminated by CEST effects from fast-exchanging amines at 3 ppm and intermediate-exchanging amines at 2 ppm. The current work applies an exchange-dependent relaxation rate (R ex ) to address this problem. Simulations demonstrate that: (1) slowly exchanging amides and fast-exchanging amines have distinct dependences on irradiation powers; and (2) R ex serves as a resonance frequency high-pass filter to selectively reduce CEST signals with resonance frequencies closer to water. These characteristics of R ex provide a means to isolate the APT signal from amines. In addition, previous studies have shown that CEST signals from fast-exchanging amines have no distinct features around their resonance frequencies. However, R ex gives Lorentzian lineshapes centered at their resonance frequencies for fast-exchanging amines and thus can significantly increase the specificity of CEST imaging for amides and fast-exchanging amines. Copyright © 2017 John Wiley & Sons

The influence of device geometry on many-body effects in quantum point contacts : Signatures of the 0.7 anomaly, exchange and kondo

NARCIS (Netherlands)

Koop, E. J.; Lerescu, A. I.; Liu, J.; van Wees, B. J.; Reuter, D.; Wieck, A. D.; van der Wal, C. H.

The conductance of a quantum point contact (QPC) shows several features that result from many-body electron interactions. The spin degeneracy in zero magnetic field appears to be spontaneously lifted due to the so-called 0.7 anomaly. Further, the g-factor for electrons in the QPC is enhanced, and a

Quasi-isentropic compressibility of a strongly nonideal deuterium plasma at pressures of up to 5500 GPa: Nonideality and degeneracy effects

Energy Technology Data Exchange (ETDEWEB)

Mochalov, M. A., E-mail: postmaster@ifv.vniief.ru; Il’kaev, R. I. [Russian Federal Nuclear Center All-Russia Research Institute for Nuclear Physics (Russian Federation); Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Mikhailov, A. L.; Blikov, A. O.; Ogorodnikov, V. A. [Russian Federal Nuclear Center All-Russia Research Institute for Nuclear Physics (Russian Federation); Gryaznov, V. K. [Russian Academy of Sciences, Institute for Problems of Chemical Physics (Russian Federation); Iosilevskii, I. L. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2017-03-15

We report on the experimental results on the quasi-isentropic compressibility of a strongly nonideal deuterium plasma that have been obtained on setups of cylindrical and spherical geometries in the pressure range of up to P ≈ 5500 GPa. We describe the characteristics of experimental setups, as well as the methods for the diagnostics and interpretation of the experimental results. The trajectory of metal shells that compress the deuterium plasma was detected using powerful pulsed X-ray sources with a maximal electron energy of up to 60 MeV. The values of the plasma density, which varied from ρ ≈ 0.8 g/cm{sup 3} to ρ ≈ 6 g/cm{sup 3}, which corresponds to pressure P ≈ 5500 GPa (55 Mbar), were determined from the measured value of the shell radius at the instant that it was stopped. The pressure of the compressed plasma was determined using gasdynamic calculations taking into account the actual characteristics of the experimental setups. We have obtained a strongly compressed deuterium plasma in which electron degeneracy effects under the conditions of strong interparticle interaction are significant. The experimental results have been compared with the theoretical models of a strongly nonideal partly degenerate plasma. We have obtained experimental confirmation of the plasma phase transition in the pressure range near 150 GPa (1.5 Mbar), which is in keeping with the conclusion concerning anomaly in the compressibility of the deuterium plasma drawn in [1].

Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 4

International Nuclear Information System (INIS)

Stamberg, K.; Plicka, J.; Calibar, J.; Gosman, A.

1985-01-01

The kinetics of ion exchange in the Nasup(+)-Mgsup(2+)-strongly acidic cation exchanger system in a batch stirred reactor was studied. The samples of exchangers OSTION KS (containing DVB in the range of 1.5 - 12%) and AMBERLITE IR 120 for experimental work were used; the concentration of the aqueous nitrate solution was always 0.2M. The Nernst-Planck equation for description of diffusion of ions in a particle was used. The values of diffusion coefficients of magnesium ions in the exchangers and their dependence on the content of DVB were obtained by evaluating the experimental data and using the self-diffusion coefficients of sodium. (author)

Exchange rate regulation, the behavior of exchange rates, and macroeconomic stability in Brazil

Directory of Open Access Journals (Sweden)

Francisco Eduardo Pires de Souza

2011-12-01

Full Text Available In the last two decades an entirely new set of rules governing the foreign exchange transactions was established in Brazil, substituting for the framework inherited from the 1930s. Foreign exchange controls were dismantled and a floating exchange rate regime replaced different forms of peg. In this paper we argue that although successful by comparison to previous experiences, the current arrangement has important flaws that should be addressed. We discuss how it first led to high volatility and extremely high interest rates, which, when overcome, gave way to a long lasting appreciation of the real exchange rate with adverse consequences to industry.

Comparison between conventional heat exchanger performance and an heat pipes exchanger

International Nuclear Information System (INIS)

Souza, J.R.G. de; Rocha, N.R.

1989-01-01

The thermal performance of conventional compact heat exchanger and of exchanger with heat pipes are simulated using a digital computer, for equal volumes and the same process conditions. The comparative analysis is depicted in graphs that indicate which of the situations each equipment is more efficient. (author)

A spin exchange model for singlet fission

Science.gov (United States)

Yago, Tomoaki; Wakasa, Masanobu

2018-03-01

Singlet fission has been analyzed with the Dexter model in which electron exchange occurs between chromophores, conserving the spin for each electron. In the present study, we propose a spin exchange model for singlet fission. In the spin exchange model, spins are exchanged by the exchange interaction between two electrons. Our analysis with simple spin functions demonstrates that singlet fission is possible by spin exchange. A necessary condition for spin exchange is a variation in exchange interactions. We also adapt the spin exchange model to triplet fusion and triplet energy transfer, which often occur after singlet fission in organic solids.

Ion-exchange chromatographic protein refolding

NARCIS (Netherlands)

Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.

2010-01-01

The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process

Frustrated Heisenberg Antiferromagnets on Cubic Lattices: Magnetic Structures, Exchange Gaps, and Non-Conventional Critical Behaviour

OpenAIRE

Ignatenko, A. N.; Irkhin, V. Yu.

2016-01-01

We have studied the Heisenberg antiferromagnets characterized by the magnetic structures with the periods being two times larger than the lattice period. We have considered all the types of the Bravais lattices (simple cubic, bcc and fcc) and divided all these antiferromagnets into 7 classes i.e. 3 plus 4 classes denoted with symbols A and B correspondingly. The order parameter characterizing the degeneracies of the magnetic structures is an ordinary Neel vector for A classes and so-called 4-...

31 CFR 500.325 - National securities exchange.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 500.325... Definitions § 500.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

31 CFR 515.325 - National securities exchange.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 515.325... Definitions § 515.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

Problems connected with the use of oligonucleotide probes with a high degree of degeneracy. Identification of mRNA and of cDNA clones corresponding to the gene of the. cap alpha. -subunit of Na/sup +/, K/sup +/-ATPase

Energy Technology Data Exchange (ETDEWEB)

Petrukhin, K.E.; Grishin, A.V.; Arsenyan, S.G.; Broude, N.E.; Grinkevich, V.A.; Filippova, L.Yu.; Severtsova, I.V.; Modyanov, N.N.

1986-10-01

To identify and search for nucleotide sequences containing the structural part of the gene of the ..cap alpha..-subunit of Na/sup +/, K/sup +/-ATPase, 17-membered oligonucleotide probes corresponding to the peptide Lys-Asp-Ala-Phe-Gln-Asn have been synthesized. It has been shown that, with a 64-fold degeneracyd, the 17-membered probe is suitable only for the identification of a specific sequence in mRNA. To search for clones containing cDNA fragments, preliminary fractionation of the probes with the aid of HPLC or the resynthesis of groups of oligonucleotides with a lower degeneracy is necessary.

An Empirical Investigation into Exchange Rate Regime Choice and Exchange Rate Volatility

OpenAIRE

Helge Berger; Jan-Egbert Sturm; Jakob de Haan

2000-01-01

We test a simple model of exchange rate regime choice with data for 65 non-OECD countries covering the period 1980-94. We find that the variance of output at home and in potential target c ountries as well as the correlation between home and foreign real activity are powerful and robust predictors of exchange rate regime choice. Surprisingly, a more volatile foreign economy can be an argument in favor of a fixed exchange rate regime once similarities in the business cycle are taken into accou...

Ion exchange technology assessment report

International Nuclear Information System (INIS)

Duhn, E.F.

1992-01-01

In the execution of its charter, the SRS Ion Exchange Technology Assessment Team has determined that ion exchange (IX) technology has evolved to the point where it should now be considered as a viable alternative to the SRS reference ITP/LW/PH process. The ion exchange media available today offer the ability to design ion exchange processing systems tailored to the unique physical and chemical properties of SRS soluble HLW's. The technical assessment of IX technology and its applicability to the processing of SRS soluble HLW has demonstrated that IX is unquestionably a viable technology. A task team was chartered to evaluate the technology of ion exchange and its potential for replacing the present In-Tank Precipitation and proposed Late Wash processes to remove Cs, Sr, and Pu from soluble salt solutions at the Savannah River Site. This report documents the ion exchange technology assessment and conclusions of the task team

PRTR ion exchange vault column sampling

International Nuclear Information System (INIS)

Cornwell, B.C.

1995-01-01

This report documents ion exchange column sampling and Non Destructive Assay (NDA) results from activities in 1994, for the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. The objective was to obtain sufficient information to prepare disposal documentation for the ion exchange columns found in the PRTR Ion exchange vault. This activity also allowed for the monitoring of the liquid level in the lower vault. The sampling activity contained five separate activities: (1) Sampling an ion exchange column and analyzing the ion exchange media for purpose of waste disposal; (2) Gamma and neutron NDA testing on ion exchange columns located in the upper vault; (3) Lower vault liquid level measurement; (4) Radiological survey of the upper vault; and (5) Secure the vault pending waste disposal

Custom, contract, and kidney exchange.

Science.gov (United States)

Healy, Kieran; Krawiec, Kimberly D

2012-01-01

In this Essay, we examine a case in which the organizational and logistical demands of a novel form of organ exchange (the nonsimultaneous, extended, altruistic donor (NEAD) chain) do not map cleanly onto standard cultural schemas for either market or gift exchange, resulting in sociological ambiguity and legal uncertainty. In some ways, a NEAD chain resembles a form of generalized exchange, an ancient and widespread instance of the norm of reciprocity that can be thought of simply as the obligation to “pay it forward” rather than the obligation to reciprocate directly with the original giver. At the same time, a NEAD chain resembles a string of promises and commitments to deliver something in exchange for some valuable consideration--that is, a series of contracts. Neither of these salient "social imaginaries" of exchange--gift giving or formal contract--perfectly meets the practical demands of the NEAD system. As a result, neither contract nor generalized exchange drives the practice of NEAD chains. Rather, the majority of actual exchanges still resemble a simpler form of exchange: direct, simultaneous exchange between parties with no time delay or opportunity to back out. If NEAD chains are to reach their full promise for large-scale, nonsimultaneous organ transfer, legal uncertainties and sociological ambiguities must be finessed, both in the practices of the coordinating agencies and in the minds of NEAD-chain participants. This might happen either through the further elaboration of gift-like language and practices, or through a creative use of the cultural form and motivational vocabulary, but not necessarily the legal and institutional machinery, of contract.

New type fuel exchange system

International Nuclear Information System (INIS)

Meshii, Toshio; Maita, Yasushi; Hirota, Koichi; Kamishima, Yoshio.

1988-01-01

When the reduction of the construction cost of FBRs is considered from the standpoint of the machinery and equipment, to make the size small and to heighten the efficiency are the assigned mission. In order to make a reactor vessel small, it is indispensable to decrease the size of the equipment for fuel exchange installed on the upper part of a core. Mitsubishi Heavy Industries Ltd. carried out the research on the development of a new type fuel exchange system. As for the fuel exchange system for FBRs, it is necessary to change the mode of fuel exchange from that of LWRs, such as handling in the presence of chemically active sodium and inert argon atmosphere covering it and handling under heavy shielding against high radiation. The fuel exchange system for FBRs is composed of a fuel exchanger which inserts, pulls out and transfers fuel and rotary plugs. The mechanism adopted for the new type fuel exchange system that Mitsubishi is developing is explained. The feasibility of the mechanism on the upper part of a core was investigated by water flow test, vibration test and buckling test. The design of the mechanism on the upper part of the core of a demonstration FBR was examined, and the new type fuel exchange system was sufficiently applicable. (Kako, I.)

Transition from reversible to irreversible magnetic exchange-spring processes in antiferromagnetically exchange-coupled hard/soft/hard trilayer structures

International Nuclear Information System (INIS)

Wang Xiguang; Guo Guanghua; Zhang Guangfu

2011-01-01

The demagnetization processes of antiferromagnetically exchange-coupled hard/soft/hard trilayer structures have been studied based on the discrete one-dimensional atomic chain model and the linear partial domain-wall model. It is found that, when the magnetic anisotropy of soft layer is taken into account, the changes of the soft layer thickness and the interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible magnetic exchange-spring process. For the trilayer structures with very thin soft layer, the demagnetization process exhibits typical reversible exchange-spring behavior. However, as the thickness of soft layer is increased, there is a crossover point t c , after which the process becomes irreversible. Similarly, there is also a critical interfacial exchange coupling constant A sh c , above which the exchange-spring process is reversible. When A sh sh c , the irreversible exchange-spring process is achieved. The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling A sh and soft layer thickness N s . - Research highlights: → A differing magnetic exchange-spring process is found in antiferromagnetically exchange-coupled hard/soft/hard trilayers if the magnetic anisotropy of the soft layers is taken into account. → The change of the soft layer thickness may lead to a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The change of the soft-hard interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling and soft layer thickness.

Indiana Health Information Exchange

Science.gov (United States)

The Indiana Health Information Exchange is comprised of various Indiana health care institutions, established to help improve patient safety and is recognized as a best practice for health information exchange.

Exchange effects in Relativistic Schroedinger Theory

International Nuclear Information System (INIS)

Sigg, T.; Sorg, M.

1998-01-01

The Relativistic Schroedinger Theory predicts the occurrence of exchange and overlap effects in many-particle systems. For a 2-particle system, the interaction energy of the two particles consists of two contributions: Coulomb energy and exchange energy, where the first one is revealed to be the same as in standard quantum theory. However the exchange energy is mediated by an exchange potential, contrary to the kinematical origin of the exchange term in the standard theory

Effective Exchange Rate Classifications and Growth

OpenAIRE

Justin M. Dubas; Byung-Joo Lee; Nelson C. Mark

2005-01-01

We propose an econometric procedure for obtaining de facto exchange rate regime classifications which we apply to study the relationship between exchange rate regimes and economic growth. Our classification method models the de jure regimes as outcomes of a multinomial logit choice problem conditional on the volatility of a country's effective exchange rate, a bilateral exchange rate and international reserves. An `effective' de facto exchange rate regime classification is then obtained by as...

Exchange currents in nuclear physics

International Nuclear Information System (INIS)

Truglik, Eh.

1980-01-01

Starting from Adler's low-energy theorem for the soft pion production amplitudes the predictions of the meson exchange currents theory for the nuclear physics are discussed. The results are reformulated in terms of phenomenological lagrangians. This method allows one to pass naturally to the more realistic case of hard mesons. The predictions are critically compared with the existing experimental data. The main processes in which vector isovector exchange currents, vector isoscalar exchange currents and axial exchange currents take place are pointed out

Can positive social exchanges buffer the detrimental effects of negative social exchanges? Age and gender differences.

Science.gov (United States)

Fiori, Katherine L; Windsor, Tim D; Pearson, Elissa L; Crisp, Dimity A

2013-01-01

Findings from existing research exploring whether positive social exchanges can help to offset (or 'buffer' against) the harmful effects of negative social exchanges on mental health have been inconsistent. This could be because the existing research is characterized by different approaches to studying various contexts of 'cross-domain' and 'within-domain' buffering, and/or because the nature of buffering effects varies according to sociodemographic characteristics that underlie different aspects of social network structure and function. The purpose of this study was to examine whether the buffering effects of global perceptions of positive exchanges on the link between global negative exchanges and mental health varied as a function of age and gender. We used a series of regressions in a sample of 556 Australian older adults (ages 55-94) to test for three-way interactions among gender, positive social exchanges, and negative social exchanges, as well as age and positive and negative social exchanges, in predicting mental health, controlling for years of education, partner status, and physical functioning. We found that positive exchanges buffered against negative exchanges for younger old adults, but not for older old adults, and for women, but not for men. Our findings are interpreted in light of research on individual differences in coping responses and interpersonal goals among late middle-aged and older adults. Our findings are in line with gerontological theories (e.g., socioemotional selectivity theory), and imply that an intervention aimed at using positive social exchanges as a means of coping with negative social exchanges might be more successful among particular populations (i.e., women, 'younger' old adults). Copyright © 2012 S. Karger AG, Basel.

Isolating the exchanges in multiple production

International Nuclear Information System (INIS)

Pirila, P.; Thomas, G.H.; Quigg, C.

1975-01-01

We employ rapidity-gap distributions to identify and study the exchanges between hadron clusters produced in collisions at Fermilab energies. The observation of charge exchange disproves the neutral cluster model. At these energies, the data are consistent with the independent emission of clusters of limited charge or with a true limited-charge-exchange picture. For exchange models, two important parameters are identified: the ratio between vertical-bar ΔQ vertical-bar = 1 and ΔQ = 0 exchange, and the ratio between the density in rapidity of charged clusters and that of neutral clusters. In principle, both of these quantities are measurable, but with existing data only the first can be determined. We use a unitarity calculation to estimate the second. Given an exchange model which fits rapidity-gap distributions, we obtain a solution to the counting problem in the overlap-function calculation of the energy dependence of two-body charge exchange, and estimate the suppression of charge exchange with respect to elastic scattering

Integrated Foreign Exchange Risk Management

DEFF Research Database (Denmark)

Aabo, Tom; Høg, Esben; Kuhn, Jochen

Empirical research has focused on export as a proxy for the exchange rate exposure and the use of foreign exchange derivatives as the instrument to deal with this exposure. This empirical study applies an integrated foreign exchange risk management approach with a particular focus on the role...

Back-exchange: a novel approach to quantifying oxygen diffusion and surface exchange in ambient atmospheres.

Science.gov (United States)

Cooper, Samuel J; Niania, Mathew; Hoffmann, Franca; Kilner, John A

2017-05-17

A novel two-step Isotopic Exchange (IE) technique has been developed to investigate the influence of oxygen containing components of ambient air (such as H 2 O and CO 2 ) on the effective surface exchange coefficient (k*) of a common mixed ionic electronic conductor material. The two step 'back-exchange' technique was used to introduce a tracer diffusion profile, which was subsequently measured using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The isotopic fraction of oxygen in a dense sample as a function of distance from the surface, before and after the second exchange step, could then be used to determine the surface exchange coefficient in each atmosphere. A new analytical solution was found to the diffusion equation in a semi-infinite domain with a variable surface exchange boundary, for the special case where D* and k* are constant for all exchange steps. This solution validated the results of a numerical, Crank-Nicolson type finite-difference simulation, which was used to extract the parameters from the experimental data. When modelling electrodes, D* and k* are important input parameters, which significantly impact performance. In this study La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF6428) was investigated and it was found that the rate of exchange was increased by around 250% in ambient air compared to high purity oxygen at the same pO 2 . The three experiments performed in this study were used to validate the back-exchange approach and show its utility.

Key Exchange Trust Evaluation in Peer-to-Peer Sensor Networks With Unconditionally Secure Key Exchange

Science.gov (United States)

Gonzalez, Elias; Kish, Laszlo B.

2016-03-01

As the utilization of sensor networks continue to increase, the importance of security becomes more profound. Many industries depend on sensor networks for critical tasks, and a malicious entity can potentially cause catastrophic damage. We propose a new key exchange trust evaluation for peer-to-peer sensor networks, where part of the network has unconditionally secure key exchange. For a given sensor, the higher the portion of channels with unconditionally secure key exchange the higher the trust value. We give a brief introduction to unconditionally secured key exchange concepts and mention current trust measures in sensor networks. We demonstrate the new key exchange trust measure on a hypothetical sensor network using both wired and wireless communication channels.

O3 and NOx Exchange

NARCIS (Netherlands)

Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.

2015-01-01

This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

Empirical Correction for Differences in Chemical Exchange Rates in Hydrogen Exchange-Mass Spectrometry Measurements.

Science.gov (United States)

Toth, Ronald T; Mills, Brittney J; Joshi, Sangeeta B; Esfandiary, Reza; Bishop, Steven M; Middaugh, C Russell; Volkin, David B; Weis, David D

2017-09-05

A barrier to the use of hydrogen exchange-mass spectrometry (HX-MS) in many contexts, especially analytical characterization of various protein therapeutic candidates, is that differences in temperature, pH, ionic strength, buffering agent, or other additives can alter chemical exchange rates, making HX data gathered under differing solution conditions difficult to compare. Here, we present data demonstrating that HX chemical exchange rates can be substantially altered not only by the well-established variables of temperature and pH but also by additives including arginine, guanidine, methionine, and thiocyanate. To compensate for these additive effects, we have developed an empirical method to correct the hydrogen-exchange data for these differences. First, differences in chemical exchange rates are measured by use of an unstructured reporter peptide, YPI. An empirical chemical exchange correction factor, determined by use of the HX data from the reporter peptide, is then applied to the HX measurements obtained from a protein of interest under different solution conditions. We demonstrate that the correction is experimentally sound through simulation and in a proof-of-concept experiment using unstructured peptides under slow-exchange conditions (pD 4.5 at ambient temperature). To illustrate its utility, we applied the correction to HX-MS excipient screening data collected for a pharmaceutically relevant IgG4 mAb being characterized to determine the effects of different formulations on backbone dynamics.

Mastering Microsoft Exchange Server 2013

CERN Document Server

Elfassy, David

2013-01-01

The bestselling guide to Exchange Server, fully updated for the newest version Microsoft Exchange Server 2013 is touted as a solution for lowering the total cost of ownership, whether deployed on-premises or in the cloud. Like the earlier editions, this comprehensive guide covers every aspect of installing, configuring, and managing this multifaceted collaboration system. It offers Windows systems administrators and consultants a complete tutorial and reference, ideal for anyone installing Exchange Server for the first time or those migrating from an earlier Exchange Server version.Microsoft

Transendothelial lipoprotein exchange and microalbuminuria

DEFF Research Database (Denmark)

Jensen, Jan Skov; Feldt-Rasmussen, Bo; Jensen, Kurt Svarre

2004-01-01

OBJECTIVE: Microalbuminuria associates with increased risk of atherosclerosis in individuals without diabetes. We hypothesized that transendothelial lipoprotein exchange is elevated among such individuals, possibly explaining increased intimal lipoprotein accumulation and thus atherosclerosis....... METHODS: Using an in vivo isotope technique, transendothelial exchange of low density lipoprotein (LDL) was measured in 77 non-diabetic individuals. Autologous 131-iodinated LDL was reinjected intravenously, and the 1-h fractional escape rate was calculated as index of transendothelial exchange. RESULTS......: There was no difference in transendothelial LDL exchange between subjects with microalbuminuria versus normoalbuminuria (mean (95% confidence interval) 3.8%/h (3.3-4.3%/h) versus 4.2%/h (3.7-4.7%/h); P=0.33). In contrast, there was a positive correlation between transendothelial LDL exchange and (logarithmically...

Heat exchanger performance monitoring guidelines

International Nuclear Information System (INIS)

Stambaugh, N.; Closser, W. Jr.; Mollerus, F.J.

1991-12-01

Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method

Conflict and Fairness in Social Exchange

Science.gov (United States)

Molm, Linda D.; Collett, Jessica L.; Schaefer, David R.

2006-01-01

Inherent to all social exchange relations are elements of both cooperation and competition. We develop and test a theoretical model which proposes that the relative salience of the competitive, conflictual elements of exchange mediate and explain the negative effects of negotiated exchange, as compared with reciprocal exchange, on actors'…

NCHRP peer exchange 2008.

Science.gov (United States)

2008-09-01

Peer exchanges for state department of transportation (DOT) research programs originated with : the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA). That federal legislation : required the states to conduct periodic peer exchanges to...

Local Road Safety Peer Exchange - Regions 3 & 5 : An RSPCB Peer Exchange

Science.gov (United States)

2013-06-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Columbus, Ohio on June 12 and 13, 2013. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with the Region 3 & 5 Local...

Exchange Rate Policy in Philippine Development

OpenAIRE

Bautista, Romeo M.

2003-01-01

This paper examines the conduct of exchange rate policy in the Philippines since the early 1980s, paying particular attention to the influence of exchange rate adjustments on relative production incentives. While primary interest is in the exchange rate regime and its incentive effects, the role of trade policy has to be simultaneously analyzed in view of its influence on the conduct of exchange rate policy as well as its direct effect on the real exchange rate. Moreover, there are analytical...

Method of relative comparison of the thermohydraulic efficiency of heat exchange intensification in channels of heat-exchange surfaces

International Nuclear Information System (INIS)

Dubrovskij, E.V.; Vasil'ev, V.Ya.

2002-01-01

One introduces a technique to compare relatively thermohydraulic efficiency of heat transfer intensification in channels of heat exchange surfaces of any design types. It is shown that one should compare thermohydraulic efficiency of heat exchange intensification as to the thermal power of heat exchangers and pressure losses in channels with turbulators and in polished channels of heat exchange surfaces on the basis of dimensions of heat exchangers, their heat exchange surfaces and at similar (as to Re numbers) modes of coolant flow [ru

Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets

Energy Technology Data Exchange (ETDEWEB)

Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

2017-05-15

Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.

Ion exchange behaviour of citrate and EDTA anions on strong and weak base organic ion exchangers

International Nuclear Information System (INIS)

Askarieh, M.M.; White, D.A.

1988-01-01

The exchange of citrate and EDTA ions with two strong base and two weak base exchangers is considered. Citrate and EDTA analysis for this work was performed using a colorimetric method developed here. The ions most selectively exchanged on the resins are H 2 cit - and H 2 EDTA 2- , though EDTA is generally less strongly sorbed on strong base resins. In contact with weak base resins, deprotonation of the resin occurs during ion exchange with a noticeable drop in solution pH. Although EDTA sorption can be reversed by nitric acid, citrate ions are significantly held on the resin at low pH. The exchange of citrate can be made reversible if bicarbonate is added to the initial solutions. Alkaline regeneration of exchangers loaded with EDTA proved to be very effective. (author)

76 FR 79254 - Self-Regulatory Organizations; EDGA Exchange, Inc.; EDGX Exchange, Inc.; Order Approving Proposed...

Science.gov (United States)

2011-12-21

... Market Maker'') in a derivative securities product (``UTP Derivative Security'') that derives its value... Derivative Security on the Exchange(s) from acting or registering as a market maker on any other exchange in any Reference Asset of that UTP Derivative Security, or any derivative instrument based on a Reference...

Exotic baryonium exchanges

International Nuclear Information System (INIS)

Nicolescu, B.

1978-05-01

The prominent effects supposed to be associated with the exchange of exotic baryonium Regge trajectories are reviewed. The experimental presence of all expected effects leads to suggest that the baryonium exchange mechanism is a correct phenomenological picture and that mesons with isospin 2 or 3/2 or with strangeness 2, strongly coupled to the baryon-antibaryon channels, must be observed

The reactivity of anion-exchange resins by applying OT-for-OH exchange reaction in the equilibrium state

International Nuclear Information System (INIS)

Kano, Naoki; Nihei, Makoto; Imaizumi, Hiroshi

1996-01-01

In order to reveal the behavior of hydroxyl group in isotope exchange reaction, OT-for-OH exchange reaction between each anion-exchange resin (OH - form) and tritiated water (abbreviated as HTO water below) was observed at 80degC under the equilibrium. Anion-exchange resins used were Amberlite IRA-400, IRA-410 (both strongly basic), and IRA-94S (weakly basic). It can be thought that an HTO molecule dissociates into H + +OT - (or T + +OH - ). The activity of each resin based on OT-for-OH exchange reaction was measured with a liquid scintillation counter. From the above-mentioned, the following five were found. Isotope exchange reaction as 'atomic group' occurred between the OH group in each anion-exchange resin and the OT group in HTO water. The reactivity of strongly basic anion-exchange resin is larger than that of weakly basic one. The ratio of the reactivity of these resins can roughly be expressed as follows: (IRA-410): (IRA-400): (IRA-94S)=42: 7: 1. The degree of OT-for-OH exchange reaction may be smaller than that of T-for-H exchange reaction. The method used and results obtained in this work may be helpful to obtain the data for the prevention of T-contamination, especially to obtain the data from certain atomic groups including T. (author)

Effects of Externalities on Patterns of Exchange

NARCIS (Netherlands)

Dijkstra, J.; van Assen, M.A.L.M.

Many real−life examples of exchanges with externalities exist. Externalities of exchange are defined as direct consequences of exchanges for the payoff of actors who are not involved in the exchange. This paper focuses on how externalities influence the partner choice in exchange networks. In an

Next Generation Microchannel Heat Exchangers

CERN Document Server

Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

2013-01-01

In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

Thermodynamic analysis on theoretical models of cycle combined heat exchange process: The reversible heat exchange process

International Nuclear Information System (INIS)

Zhang, Chenghu; Li, Yaping

2017-01-01

Concept of reversible heat exchange process as the theoretical model of the cycle combined heat exchanger could be useful to determine thermodynamics characteristics and the limitation values in the isolated heat exchange system. In this study, the classification of the reversible heat exchange processes is presented, and with the numerical method, medium temperature variation tendency and the useful work production and usage in the whole process are investigated by the construction and solution of the mathematical descriptions. Various values of medium inlet temperatures and heat capacity ratio are considered to analyze the effects of process parameters on the outlet temperature lift/drop. The maximum process work transferred from the Carnot cycle region to the reverse cycle region is also researched. Moreover, influence of the separating point between different sub-processes on temperature variation profile and the process work production are analyzed. In addition, the heat-exchange-enhancement-factor is defined to study the enhancement effect of the application of the idealized process in the isolated heat exchange system, and the variation degree of this factor with process parameters change is obtained. The research results of this paper can be a theoretical guidance to construct the cycle combined heat exchange process in the practical system. - Highlights: • A theoretical model of Cycle combined heat exchange process is proposed. • The classification of reversible heat exchange process are presented. • Effects of Inlet temperatures and heat capacity ratio on process are analyzed. • Process work transmission through the whole process is studied. • Heat-exchange-enhancement-factor can be a criteria to express the application effect of the idealized process.

Quantification of exchangeable and non-exchangeable organically bound tritium (OBT) in vegetation.

Science.gov (United States)

Kim, S B; Korolevych, V

2013-04-01

The objective of this study is to quantify the relative amounts of exchangeable organically bound tritium (OBT) and non-exchangeable OBT in various vegetables. A garden plot at Perch Lake, where tritium levels are slightly elevated due to releases of tritium from a nearby nuclear waste management area and Chalk River Laboratories (CRL) operations, was used to cultivate a variety of vegetables. Five different kinds of vegetables (lettuce, cabbage, tomato, radish and beet) were studied. Exchangeable OBT behaves like tritium in tissue free water in living organisms and, based on past measurements, accounts for about 20% of the total tritium in dehydrated organic materials. In this study, the percentage of the exchangeable OBT was determined to range from 20% to 57% and was found to depend on the type of vegetables as well as the sequence of the plants exposure to HTO. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Cryptographic Combinatorial Securities Exchanges

Science.gov (United States)

Thorpe, Christopher; Parkes, David C.

We present a useful new mechanism that facilitates the atomic exchange of many large baskets of securities in a combinatorial exchange. Cryptography prevents information about the securities in the baskets from being exploited, enhancing trust. Our exchange offers institutions who wish to trade large positions a new alternative to existing methods of block trading: they can reduce transaction costs by taking advantage of other institutions’ available liquidity, while third party liquidity providers guarantee execution—preserving their desired portfolio composition at all times. In our exchange, institutions submit encrypted orders which are crossed, leaving a “remainder”. The exchange proves facts about the portfolio risk of this remainder to third party liquidity providers without revealing the securities in the remainder, the knowledge of which could also be exploited. The third parties learn either (depending on the setting) the portfolio risk parameters of the remainder itself, or how their own portfolio risk would change if they were to incorporate the remainder into a portfolio they submit. In one setting, these third parties submit bids on the commission, and the winner supplies necessary liquidity for the entire exchange to clear. This guaranteed clearing, coupled with external price discovery from the primary markets for the securities, sidesteps difficult combinatorial optimization problems. This latter method of proving how taking on the remainder would change risk parameters of one’s own portfolio, without revealing the remainder’s contents or its own risk parameters, is a useful protocol of independent interest.

Fundamentals of ion exchange

International Nuclear Information System (INIS)

Townsend, R.P.

1993-01-01

In this paper the fundamentals of ion exchange mechanisms and their thermodynamics are described. A range of ion exchange materials is considered and problems of communication and technology transfer between scientists working in the field are discussed. (UK)

ION EXCHANGE IN GLASS-CERAMICS

Directory of Open Access Journals (Sweden)

George Halsey Beall

2016-08-01

Full Text Available In the past few years ion-exchange in glasses has found a renewed interest with a lot of new development and research in industrial and academic labs and the commercialization of materials with outstanding mechanical properties. These glasses are now widely used in many electronic devices including hand-held displays and tablets. The exchange is generally conducted in a bath of molten salt below the transition temperature of the glass. The exchange at the surface of an alkali ion by a bigger one brings compressive stress at the surface. The mechanical properties are dependent on the stress level at the surface and the depth of penetration of the bigger ion. As compared to glasses, glass-ceramics have the interest to display a wide range of aspects (transparent to opaque and different mechanical properties (especially higher modulus and toughness. There has been little research on ion-exchange in glass-ceramics. In these materials the mechanisms are much more complex than in glasses because of their polyphasic nature: ion-exchange generally takes place mostly in one phase (crystalline phase or residual glass. The mechanism can be similar to what is observed in glasses with the replacement of an ion by another in the structure. But in some cases this ion-exchange leads to microstructural modifications (for example amorphisation or phase change.This article reviews these ion-exchange mechanisms using several transparent and opaque alumino-silicate glass-ceramics as examples. The effect of the ion exchange in the various glass-ceramics will be described, with particular emphasis on flexural strength.

Foreign Exchange Exposures of Korean Firms

Directory of Open Access Journals (Sweden)

Sungbin Cho

2011-03-01

Full Text Available We measure foreign exchange exposures as sensitivity of firm's value to FX premium in the CAPM plus FX premium model, and try to find determinants of the exposures; using data of non-financial companies listed in the Korea Exchange from the year 2007 to 2008. Main findings are as follows. If Korean won depreciates, only a small number of firms is benefitted while majority of firms are harmed to the contrary of common knowledge. As a firm's export increases, the foreign exchange exposure increases up to a certain level and after that it declines. And, smaller firms of negative foreign exchange exposures are more sensitive to foreign exchange changes. These suggest heterogeneous effects of foreign exchange rates on industries and firms.

Flexible Exchange of Farming Device Data

DEFF Research Database (Denmark)

Iftikhar, Nadeem; Pedersen, Torben Bach

2011-01-01

A new trend in the farming business is to replace conventional farming devices with computerized farming devices. Accordingly, numerous computer-based farming devices for logging, processing and exchanging data have recently been installed on moving farm machinery such as tractors. The exchange o......-directional data exchange as well as efficient requirements change management through a graphical user interface. The paper also demonstrates the use of the proposed solution based on a farming case study and open source technologies....... and systems to exchange data based on a predefined set of rules. In consequence, many hand-coded data exchange solutions have been developed in the farming business. Although efforts regarding incorporating data exchange standards have been made, their actual usage so far has been limited, due to the fact...

Effective exchange potentials for electronically inelastic scattering

International Nuclear Information System (INIS)

Schwenke, D.W.; Staszewska, G.; Truhlar, D.G.

1983-01-01

We propose new methods for solving the electron scattering close coupling equations employing equivalent local exchange potentials in place of the continuum-multiconfiguration-Hartree--Fock-type exchange kernels. The local exchange potentials are Hermitian. They have the correct symmetry for any symmetries of excited electronic states included in the close coupling expansion, and they have the same limit at very high energy as previously employed exchange potentials. Comparison of numerical calculations employing the new exchange potentials with the results obtained with the standard nonlocal exchange kernels shows that the new exchange potentials are more accurate than the local exchange approximations previously available for electronically inelastic scattering. We anticipate that the new approximations will be most useful for intermediate-energy electronically inelastic electron--molecule scattering

Inorganic ion exchangers for nuclear waste remediation

Energy Technology Data Exchange (ETDEWEB)

Clearfield, A.; Bortun, A.; Bortun, L.; Behrens, E. [Texas A& M Univ., College Station, TX (United States)

1997-10-01

The objective of this work is to provide a broad spectrum of inorganic ion exchangers that can be used for a range of applications and separations involving remediation of groundwater and tank wastes. The authors intend to scale-up the most promising exchangers, through partnership with AlliedSignal Inc., to provide samples for testing at various DOE sites. While much of the focus is on exchangers for removal of Cs{sup +} and Sr{sup 2+} from highly alkaline tank wastes, especially at Hanford, the authors have also synthesized exchangers for acid wastes, alkaline wastes, groundwater, and mercury, cobalt, and chromium removal. These exchangers are now available for use at DOE sites. Many of the ion exchangers described here are new, and others are improved versions of previously known exchangers. They are generally one of three types: (1) layered compounds, (2) framework or tunnel compounds, and (3) amorphous exchangers in which a gel exchanger is used to bind a fine powder into a bead for column use. Most of these exchangers can be regenerated and used again.

Biodegradation of ion-exchange media

International Nuclear Information System (INIS)

Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

1988-08-01

Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs

Hydrogen/deuterium exchange in mass spectrometry.

Science.gov (United States)

Kostyukevich, Yury; Acter, Thamina; Zherebker, Alexander; Ahmed, Arif; Kim, Sunghwan; Nikolaev, Eugene

2018-03-30

The isotopic exchange approach is in use since the first observation of such reactions in 1933 by Lewis. This approach allows the investigation of the pathways of chemical and biochemical reactions, determination of structure, composition, and conformation of molecules. Mass spectrometry has now become one of the most important analytical tools for the monitoring of the isotopic exchange reactions. Investigation of conformational dynamics of proteins, quantitative measurements, obtaining chemical, and structural information about individual compounds of the complex natural mixtures are mainly based on the use of isotope exchange in combination with high resolution mass spectrometry. The most important reaction is the Hydrogen/Deuterium exchange, which is mainly performed in the solution. Recently we have developed the approach allowing performing of the Hydrogen/Deuterium reaction on-line directly in the ionization source under atmospheric pressure. Such approach simplifies the sample preparation and can accelerate the exchange reaction so that certain hydrogens that are considered as non-labile will also participate in the exchange. The use of in-ionization source H/D exchange in modern mass spectrometry for structural elucidation of molecules serves as the basic theme in this review. We will focus on the mechanisms of the isotopic exchange reactions and on the application of in-ESI, in-APCI, and in-APPI source Hydrogen/Deuterium exchange for the investigation of petroleum, natural organic matter, oligosaccharides, and proteins including protein-protein complexes. The simple scenario for adaptation of H/D exchange reactions into mass spectrometric method is also highlighted along with a couple of examples collected from previous studies. © 2018 Wiley Periodicals, Inc.

Heat exchanger

International Nuclear Information System (INIS)

Drury, C.R.

1988-01-01

A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections

Latin American foreign exchange intervention - Updated

OpenAIRE

Da Silva, Sergio; Nunes, Mauricio

2007-01-01

We examine Latin American foreign exchange intervention in a framework where the exchange rate regime is endogenous and there exists an inefficient, equilibrium foreign exchange intervention bias. The model suggests that greater central bank independence is associated with lesser intervention in the foreign exchange market, and also with leaning-against-the-wind intervention. Both results are confirmed by data from 13 Latin American countries.

Test procedure for cation exchange chromatography

International Nuclear Information System (INIS)

Cooper, T.D.

1994-01-01

The purpose of this test plan is to demonstrate the synthesis of inorganic antimonate ion exchangers and compare their performance against the standard organic cation exchangers. Of particular interest is the degradation rate of both inorganic and organic cation exchangers. This degradation rate will be tracked by determining the ion exchange capacity and thermal stability as a function of time, radiation dose, and chemical reaction

Social exchange: Relations and networks

OpenAIRE

Dijkstra, Jacob

2015-01-01

In this short paper, I review the literature on social exchange networks, with specific attention to theoretical and experimental research. I indicate how social exchange theory is rooted in general social theory and mention a few of its main links to social network analysis and empirical network research. The paper provides an accessible entry into the literature on social exchange.

Sleeving repair of heat exchanger tubes

International Nuclear Information System (INIS)

Street, Michael D.; Schafer, Bruce W.

2000-01-01

Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat

Uranium isotope separation using styrene cation exchangers

International Nuclear Information System (INIS)

Kahovec, J.

1980-01-01

The separation of 235 U and 238 U isotopes is carried out either by simple isotope exchange in the system uranium-cation exchanger (sulphonated styrene divinylbenzene resin), or by combination of isotope exchange in a uranium-cation exchanger (Dowex 50, Amberlite IR-120) system and a chemical reaction. A review is presented of elution agents used, the degree of cation exchanger cross-linking, columns length, and 235 U enrichment. The results are described of the isotope effect study in a U(IV)-U(VI)-cation exchanger system conducted by Japanese and Romanian authors (isotope exchange kinetics, frontal analysis, reverse (indirect) frontal analysis). (H.S.)

Nonadiabatic exchange dynamics during adiabatic frequency sweeps.

Science.gov (United States)

Barbara, Thomas M

2016-04-01

A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

The reactions K/sup -/p to pi /sup -or+/ Sigma /sup +or-/(1385) at 42 GeV/c

CERN Document Server

Holmgren, S O; Barreiro, F; Hemingway, R J; Kittel, E W; Kluyver, J C; Losty, Michael J; Massaro, G G G; Van de Walle, R T; Worden, R P; Zatz, J

1977-01-01

The total and differential cross sections are presented. Amplitude analyses are performed and the complete sigma /sup +or-/(1385) helicity spin density matrices are extracted. The results are compared with the predictions of the additive quark model and exchange degeneracy. A substantial cross section is observed for the reaction K /sup -/p to pi /sup +/ Sigma /sup -/(1385) in the forward direction, which implies exotic meson quantum numbers in the t-channel. One possible interpretation of this process provides an explanation for the small but significant violations of the additive quark model predictions observed in the reaction K/sup -/p to pi /sup -/ Sigma /sup +/(1385) at low four-momentum transfer. In the backward direction unnatural parity exchange is shown to give a larger contribution to K /sup -/p to Sigma /sup -/(1385) pi /sup +/ than natural parity exchange. (25 refs).

Cationic mobility in polystyrene sulfone exchangers - Application to the elution of a cation on an exchange column

International Nuclear Information System (INIS)

Menin, Jean-Pierre

1969-01-01

The aim of this work is to improve elutions and separations carried out on inorganic exchangers by selective electromigration of the ionic species to be displaced. To do this, it has been found indispensable to make a fundamental study of the mobility of cations in exchangers. As the field for this research we have chosen those organic exchangers whose structure and behaviour with respect to ion-exchange are much better known that in the case of their inorganic equivalents. We have related the idea of the equivalent conductivity to that of the cation mobility in the exchanger, and this has entailed determining the specific conductivity of the exchanger and the cation concentration in the resin. The results obtained have allowed us to draw up a hypothesis concerning the cation migration mechanism in the exchanger. The third part of our work has been the application of the preceding results to an operation on an ion-exchange column, viz. the elution by an acid solution of a single fixed ion, magnesium or strontium. This work has enabled us to show that the electromigration of a cation during its elution can markedly accelerate or retard this elution. (author) [fr

Heat exchanger cleaning

International Nuclear Information System (INIS)

Gatewood, J.R.

1980-01-01

A survey covers the various types of heat-exchange equipment that is cleaned routinely in fossil-fired generating plants, the hydrocarbon-processing industry, pulp and paper mills, and other industries; the various types, sources, and adverse effects of deposits in heat-exchange equipment; some details of the actual procedures for high-pressure water jetting and chemical cleaning of some specific pieces of equipment, including nuclear steam generators. (DN)

Exchange Rate Determinants in Russia; 1992-1993

OpenAIRE

Vincent Koen; Eric Meyermans

1994-01-01

This paper examines the evolution of the exchange rate of the ruble vis-à-vis the U.S. dollar from exchange rate unification, in July 1992, to the end of 1993. The expected and actual paths of the exchange rate are related to the exchange and trade regime and to the stance of financial and exchange rate policies. An econometric analysis based on weekly data is offered, which suggests that monetary factors have a significant impact on the short run behavior of the exchange rate.

Heat exchanger leakage problem location

Directory of Open Access Journals (Sweden)

Jícha Miroslav

2012-04-01

Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

Comparative study on bromide and iodide ion-isotopic exchange reactions using strongly basic anion exchange resin Duolite A-113

International Nuclear Information System (INIS)

Lokhande, R.S.; Dole, M.H.; Singare, P.U.

2006-01-01

Kinetics of ion-isotopic exchange reaction was studied using industrial grade ion exchange resin Duolite A-113. The radioactive isotopes 131 I and 82 Br were used to trace the ion-isotopic exchange reaction. The experiments were performed in the temperature range of 26.0degC to 43.0degC and the concentration of external ionic solution varying from 0.005 M to 0.100 M. For bromide ion-isotopic exchange reaction, the calculated values of specific reaction rate, initial rate of bromide ion exchange, and amount of bromide ions exchanged were obtained higher than that for iodide ion-isotopic exchange reaction under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions. (author)

Carboxylic acid exchangers in analytical chemistry

International Nuclear Information System (INIS)

Venkateswarlu, Ch.

1976-01-01

The literature on the use of carboxylic acid exchangers in inorganic analytical chemistry is reviewed. It is classified under two heads, based on the ionic form in which the exchanger is employed, viz., the salt form and the acid form. In the salt form, the separations reported in the beginning are mostly carried out in alkaline medium, employing ammonia and its derivatives as complexing agents to hold cations in solution. This was followed by the use of ammonium ion as an eluent from heavy weakly or neutral solutions. There are a few separations reported making use of EDTA as eluent. It appears that separation of some anions from cations can be achieved with greater ease with these exchangers than with sulphonic acid type. Contary to the general belief, carboxylic acid exchangers are used in H + form to achieve some analytical separations of cations of interest. These exchangers exhibit better sorption of some cations in presence of complexing agents containing basic nitrogen as a donor. In fact, a careful study of these exchangers with different matrices might yield really selective exchangers, than the chelating ones known commercially. From the separation cited, carboxylic acid exchangers appear to have greater potentialities in their applications, than what is normally expected. (author)

Kinetics of hydrogen isotope exchange reactions

International Nuclear Information System (INIS)

Gold, V.; McAdam, M.E.

1975-01-01

Under the influence of tritium β-radiation, 1,4-dioxan undergoes hydrogen exchange with the solvent water. The inhibition of the reaction by known electron scavengers (Ag + , Cu 2+ , Ni 2+ , Co 2+ , Zn 2+ , H 3 + O) and also by species with high reactivity towards hydroxyl radicals but negligible reactivity towards solvated electrons (N 3 - , Br - , SCN - ) has been examined in detail. γ-irradiation similarly induces hydrogen exchange. The action of scavengers is interpreted as requiring the involvement of two separately scavengeable primary radiolysis products in the sequence of reactions leading to exchange. The presence of electron scavengers, even at high concentration, does not totally inhibit the exchange, and a secondary exchange route, involving a low vacancy state of inhibitor cations, is considered responsible for the 'unscavengeable' portion of the reaction, by providing an alternative exchange route. Analogies are drawn between the exchange reaction and other radiation-induced reactions that are thought to involve spur processes. Some implication of radiation-chemical studies in water-alcohol mixtures are indicated. (author)

Domain wall engineering through exchange bias

International Nuclear Information System (INIS)

Albisetti, E.; Petti, D.

2016-01-01

The control of the structure and position of magnetic domain walls is at the basis of the development of different magnetic devices and architectures. Several nanofabrication techniques have been proposed to geometrically confine and shape domain wall structures; however, a fine tuning of the position and micromagnetic configuration is hardly achieved, especially in continuous films. This work shows that, by controlling the unidirectional anisotropy of a continuous ferromagnetic film through exchange bias, domain walls whose spin arrangement is generally not favored by dipolar and exchange interactions can be created. Micromagnetic simulations reveal that the domain wall width, position and profile can be tuned by establishing an abrupt change in the direction and magnitude of the exchange bias field set in the system. - Highlights: • Micromagnetic simulations study domain walls in exchange biased thin films. • Novel domain wall configurations can be stabilized via exchange bias. • Domain walls nucleate at the boundary of regions with different exchange bias. • Domain wall width and spin profile are controlled by tuning the exchange bias.

Heat exchanger vibration

International Nuclear Information System (INIS)

Richards, D.J.W.

1977-01-01

The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration

Heat exchanger vibration

Energy Technology Data Exchange (ETDEWEB)

Richards, D J.W. [CERL, CEGB, Leatherhead, Surrey (United Kingdom)

1977-12-01

The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration.

Tubular heat exchanger

International Nuclear Information System (INIS)

Hayden, Owen; Willby, C.R.

1976-01-01

The invention concerns a heat exchanger of which the tubes, placed in a long casing, cross the casing cover in a sealed manner. These tubes are fixed to the tube plate forming this cover or to the branch tubes it comprises by means of compression joints. These joints make it possible to do away with welds that are sources of defects and to improve the operational safety of the apparatus. An advantageous form of the heat exchanger under the invention includes a manifold for each thermal exchange fluid, and one end of each tube is connected to this manifold by a pipe that is itself connected to the tube by a threaded connection. The latter provides for easy disconnection of the pipe in order to introduce a probe for inspecting the state of the tubes [fr

Fuel exchanger control device

International Nuclear Information System (INIS)

Kurabayashi, Masaharu.

1985-01-01

Purpose: To improve the stability and the operationability of the fuel exchanging work by checking the validity of the data before the initiation of the work. Constitution: A floppy disc stores the initial charging state data showing the arrangement of fuel assemblies in the reactor core pool, data showing the working procedures for the fuel exchange and a final charged state data upon completion of the work. The initial data and the procedure data are read from the disk and stored once into a memory. Then, the initial data are sequentially performed on the memory in accordance with the procedure data and, thereafter, they were compared with the final data read from the disk. After confirming that there are no errors in the working data, the procedure data are orderly instructed to the fuel exchanger for performing fuel replacement. Accordingly, since the data are checked before the initiation of the work, the fuel exchange can be performed automatically thereby improving the operationability thereof. (Yoshino, Y.)

Exchangers man the pumps

Science.gov (United States)

Barkla, Bronwyn J; Hirschi, Kendal D

2008-01-01

Tonoplast-localised proton-coupled Ca2+ transporters encoded by cation/H+ exchanger (CAX) genes play a critical role in sequestering Ca2+ into the vacuole. These transporters may function in coordination with Ca2+ release channels, to shape stimulus-induced cytosolic Ca2+ elevations. Recent analysis of Arabidopsis CAX knockout mutants, particularly cax1 and cax3, identified a variety of phenotypes including sensitivity to abiotic stresses, which indicated that these transporters might play a role in mediating the plant's stress response. A common feature of these mutants was the perturbation of H+-ATPase activity at both the tonoplast and the plasma membrane, suggesting a tight interplay between the Ca2+/H+ exchangers and H+ pumps. We speculate that indirect regulation of proton flux by the exchangers may be as important as the direct regulation of Ca2+ flux. These results suggest cautious interpretation of mutant Ca2+/H+ exchanger phenotypes that may be due to either perturbed Ca2+ or H+ transport. PMID:19841670

Heat exchange apparatus

International Nuclear Information System (INIS)

Thurston, G.C.; McDaniels, J.D.; Gertsch, P.R.

1979-01-01

The present invention relates to heat exchangers used for transferring heat from the gas cooled core of a nuclear reactor to a secondary medium during standby and emergency conditions. The construction of the heat exchanger described is such that there is a minimum of welds exposed to the reactor coolant, the parasitic heat loss during normal operation of the reactor is minimized and the welds and heat transfer tubes are easily inspectable. (UK)

GRUNDTVIG in transnational exchange

DEFF Research Database (Denmark)

Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg.......Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg....

Disposal of bead ion exchange resin wastes

International Nuclear Information System (INIS)

Gay, R.L.; Granthan, L.F.

1985-01-01

Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means

Ion exchange in ZSM-5 zeolite

International Nuclear Information System (INIS)

Matthews, D.P.; Rees, L.V.C.

1986-01-01

The ion exchange properties of Na-ZSM5 have been studied using a number of univalent and divalent cations at 25degC and 65degC. All the univalent cations studied achieved 100 per cent exchange. The thermodynamic affinity sequence Cs > Rb=NH 4 =H 3 O>K>Na>Li was found at both temperatures for a sample with Si/Al=39. Standard enthalpies of exchange ΔH o were calculated using the van't' Hoff isochore and standard entropies of exchange were then calculated from ΔH o and ΔG o . Multivalent cations were unable to achieve 100 per cent exchange. The maximum exchange was found to increase through the series Ca 2+ cations ( 57 Fe enriched) on dehydration and rehydration following sorption and desorption of ethanol. At least 3 sites for Fe 2+ were observed in the dehydrated zeolite. (author)

Electrically switched cesium ion exchange

International Nuclear Information System (INIS)

Lilga, M.A.; Orth, R.J.; Sukamto, J.P.H.; Schwartz, D.T.; Haight, S.M.; Genders, J.D.

1997-04-01

Electrically Switched Ion Exchange (ESIX) is a separation technology being developed as an alternative to conventional ion exchange for removing radionuclides from high-level waste. The ESIX technology, which combines ion exchange and electrochemistry, is geared toward producing electroactive films that are highly selective, regenerable, and long lasting. During the process, ion uptake and elution are controlled directly by modulating the potential of an ion exchange film that has been electrochemically deposited onto a high surface area electrode. This method adds little sodium to the waste stream and minimizes the secondary wastes associated with traditional ion exchange techniques. Development of the ESIX process is well underway for cesium removal using ferrocyanides as the electroactive films. Films having selectivity for perrhenate (a pertechnetate surrogate) over nitrate also have been deposited and tested. A case study for the KE Basin on the Hanford Site was conducted based on the results of the development testing. Engineering design baseline parameters for film deposition, film regeneration, cesium loading, and cesium elution were used for developing a conceptual system. Order of magnitude cost estimates were developed to compare with conventional ion exchange. This case study demonstrated that KE Basin wastewater could be processed continuously with minimal secondary waste and reduced associated disposal costs, as well as lower capital and labor expenditures

Hydrogen--deuterium exchanges in nucleosides and nucleotides. A mechanism for exchange of the exocyclic amino hydrogens of adenosine

International Nuclear Information System (INIS)

Cross, D.G.; Brown, A.; Fisher, H.F.

1975-01-01

The pH dependence of the apparent first-order rate constant for the exchange of the exocyclic amino hydrogens of adenosine with deuterium from the solvent was measured by stopped-flow ultraviolet spectroscopy. This dependence shows acid catalysis, base catalysis, and spontaneous exchange at neutral pH values. A study of the effect of several buffers on the rates of exchange reveals both general acid and general base catalytic behavior for the exchange process. We propose a general mechanism for the exchange which requires N-1 protonated adenosine as an intermediate for the acid-catalyzed exchange and amidine anion for the base-catalyzed exchange. In both cases the rate-limiting step is the base-catalyzed abstraction of a proton from the exocyclic amino moiety. Evaluation of the rate constants predicts the equilibrium for the exocyclic amino/imino tautomers to be 6.3 x 10 3 :1. (U.S.)

Research of thermal stability of ion exchangers

International Nuclear Information System (INIS)

Stuchlik, S.; Srnkova, J.

1983-01-01

Prior to the fixation of radioactive ion exchangers into bitumen these exchangers have to be dried. The resulting gaseous products may generate explosive mixtures. An analysis was made of the thermal stability of two types of ion exchangers, the cation exchanger KU-2-8 cS and the anion exchanger AV-17-8 cS which are used in the V-1 nuclear power plant at Jaslovske Bohunice. The thermal stability of the anion exchangers was monitored using gas chromatography at temperatures of 100, 120, 140, 160 and 180 degC and by measuring weight loss by kiln-drying at temperatures of 120, 140, 160 and 180 degC. The ion exchanger was heated for 6 hours and samples were taken continuously at one hour intervals. The thermal stability of the cation exchanger was monitored by measuring the weight loss. Gas chromatography showed the release of trimethylamine from the anion exchanger in direct dependence on temperature. The measurement of weight losses, however, only showed higher losses of released products which are explained by the release of other thermally unstable products. The analysis of the thermal stability of the cation exchanger showed the release of SO 2 and the weight loss (following correction for water content) was found only after the fourth hour of decomposition. The experiment showed that the drying of anion exchanger AV-17-8 cS may cause the formation of explosive mixtures. (J.P.)

The determinants of exchange rate in Croatia

Directory of Open Access Journals (Sweden)

Manuel BENAZIC

2016-06-01

Full Text Available The dilemma for every country with an independent monetary policy is which kind of exchange rate arrangement should be applied. Through the exchange rate policy, countries can influence their economies, i.e. price stability and export competiveness. Croatia is a new EU member state, it has its own monetary policy and currency but it is on the way to euro introduction. Regarding the experiences from the beginning of the 1990s when Croatia was faced with serious monetary instabilities and hyperinflation, the goal of Croatian National Bank (CNB is to ensure price stability and one way to do so is through exchange rate policy. Croatia, as a small and open economy, has applied a managed floating exchange rate regime. The exchange rate is determined primarily by the foreign exchange supply and demand on the foreign exchange market, with occasional market interventions by the CNB. Therefore, in order to maintain exchange rate stability, policymakers must be able to recognize how changes in these factors affect changes in the exchange rate. This research aims to find a relationship among the main sources of foreign currency inflow and outflow and the level of exchange rate in Croatia. The analysis is carried out by using the bounds testing (ARDL approach for co-integration. The results indicate the existence of a stable co-integration relationship between the observed variables, whereby an increase in the majority of variables leads to an exchange rate appreciation.

Data Exchange Inventory System (DEXI)

Data.gov (United States)

Social Security Administration — Enterprise tool used to identify data exchanges occurring between SSA and our trading partners. DEXI contains information on both incoming and outgoing exchanges and...

The Life Science Exchange: a case study of a sectoral and sub-sectoral knowledge exchange programme.

Science.gov (United States)

Perkins, Brian Lee; Garlick, Rob; Wren, Jodie; Smart, Jon; Kennedy, Julie; Stephens, Phil; Tudor, Gwyn; Bisson, Jonathan; Ford, David V

2016-04-27

Local and national governments have implemented sector-specific policies to support economic development through innovation, entrepreneurship and knowledge exchange. Supported by the Welsh Government through the European Regional Development Fund, The Life Science Exchange® project was created with the aim to increase interaction between stakeholders, to develop more effective knowledge exchange mechanisms, and to stimulate the formation and maintenance of long-term collaborative relationships within the Welsh life sciences ecosystem. The Life Science Exchange allowed participants to interact with other stakeholder communities (clinical, academic, business, governmental), exchange perspectives and discover new opportunities. Six sub-sector focus groups comprising over 200 senior stakeholders from academia, industry, the Welsh Government and National Health Service were established. Over 18 months, each focus group provided input to inform healthcare innovation policy and knowledge mapping exercises of their respective sub-sectors. Collaborative projects identified during the focus groups and stakeholder engagement were further developed through sandpit events and bespoke support. Each sub-sector focus group produced a report outlining the significant strengths and opportunities in their respective areas of focus, made recommendations to overcome any 'system failures', and identified the stakeholder groups which needed to take action. A second outcome was a stakeholder-driven knowledge mapping exercise for each area of focus. Finally, the sandpit events and bespoke support resulted in participants generating more than £1.66 million in grant funding and inward investment. This article outlines four separate outcomes from the Life Science Exchange programme. The Life Science Exchange process has resulted in a multitude of collaborations, projects, inward investment opportunities and special interest group formations, in addition to securing over ten times its own

Exchange Reactions. Proceedings of the Symposium on Exchange Reactions

International Nuclear Information System (INIS)

1965-01-01

The mechanisms and kinetics of chemical reactions are of great interest to chemists. The study of exchange reactions in particular helps to shed light on the dynamics of chemical change, providing an insight into the structures and the reactivities of the chemical species involved. The main theme of this meeting was the subject of oxidation-reduction reactions in which the net result is the transfer of one or more electrons between the different oxidation states of the same element. Other studies reported included the transfer of protons, atoms, complex ligands or organic radicals between molecules. Heterogeneous exchange, which is of importance in many cases of catalytic action, was also considered. For a long time isotopic tracers have formed the most convenient means of studying exchange reactions and today a considerable amount of work continues to be done with their aid. Consequently, several papers presented at this Symposium reported on work carried out by purely radiochemical tracer methods. In recognition, however, of the important role which nuclear magnetic resonance and electron spin resonance play in this field, in particular in the study of fast reactions, a number of reports on investigations in which these techniques had been used was included in the programme. By kind invitation of the United States Government the Symposium on Exchange Reactions was held from 31 May to 4 June at the Brookhaven National Laboratory, Upton, Long Island, N.Y., USA. It was attended by 46 participants from nine countries and one inter-governmental organization. The publication of these Proceedings makes the contents of the papers and the discussion available to a wider audience

Exchange rate smoothing in Hungary

OpenAIRE

Karádi, Péter

2005-01-01

The paper proposes a structural empirical model capable of examining exchange rate smoothing in the small, open economy of Hungary. The framework assumes the existence of an unobserved and changing implicit exchange rate target. The central bank is assumed to use interest rate policy to obtain this preferred rate in the medium term, while market participants are assumed to form rational expectations about this target and influence exchange rates accordingly. The paper applies unobserved varia...

Method of solidifying radioactive ion exchange resin

International Nuclear Information System (INIS)

Minami, Yuji; Tomita, Toshihide

1989-01-01

Spent anion exchange resin formed in nuclear power plants, etc. generally catch only a portion of anions in view of the ion exchange resins capacity and most of the anions are sent while possessing activities to radioactive waste processing systems. Then, the anion exchange resins increase the specific gravity by the capture of the anions. Accordingly, anions are caused to be captured on the anion exchange resin wastes such that the specific gravity of the anion exchange resin wastes is greater than that of the thermosetting resins to be mixed. This enables satisfactory mixing with the thermosetting resins and, in addition, enables to form integral solidification products in which anion exchange resins and cation exchange resins are not locallized separately and which are homogenous and free from cracks. (T.M.)

Decomposing method for ion exchange resin

International Nuclear Information System (INIS)

Sako, Takeshi; Sato, Shinshi; Akai, Yoshie; Moniwa, Shinobu; Yamada, Kazuo

1998-01-01

The present invention concerns a method of decomposing ion exchange resins generated in a nuclear power plant to carbon dioxide reliably in a short period of time. (1) The ion exchange resins are mixed with water, and then they are kept for a predetermined period of time in the presence of an inert gas at high temperature and high pressure exceeding the critical point of water to decompose the ion exchange resins. (2) The ion exchange resins is mixed with water, an oxidant is added and they are kept for a predetermined time in the presence of an inert gas at a high temperature and a high pressure exceeding a critical point of water of an inert gas at a high temperature to decompose the ion exchange resins. (3) An alkali or acid is added to ion exchange resins and water to control the hydrogen ion concentration in the solution and the ion exchange resins are decomposed in above-mentioned (1) or (2). Sodium hydroxide is used as the alkali and hydrochloric acid is used as the acid. In addition, oxygen, hydrogen peroxide or ozone is used as an oxidant. (I.S.)

Ion exchange phenomena

Energy Technology Data Exchange (ETDEWEB)

Bourg, I.C.; Sposito, G.

2011-05-01

Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).

32 CFR 644.418 - Procedure for exchange.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Procedure for exchange. 644.418 Section 644.418... for exchange. (a) Each agreement for the exchange of real property should be formalized by written contract specifying the terms and conditions of the exchange, including, by reference to exhibits...

New Trends in Magnetic Exchange Bias

Science.gov (United States)

Mougin, Alexandra; Mangin, Stéphane; Bobo, Jean-Francois; Loidl, Alois

2005-05-01

The study of layered magnetic structures is one of the hottest topics in magnetism due to the growing attraction of applications in magnetic sensors and magnetic storage media, such as random access memory. For almost half a century, new discoveries have driven researchers to re-investigate magnetism in thin film structures. Phenomena such as giant magnetoresistance, tunneling magnetoresistance, exchange bias and interlayer exchange coupling led to new ideas to construct devices, based not only on semiconductors but on a variety of magnetic materials Upon cooling fine cobalt particles in a magnetic field through the Néel temperature of their outer antiferromagnetic oxide layer, Meiklejohn and Bean discovered exchange bias in 1956. The exchange bias effect through which an antiferromagnetic AF layer can cause an adjacent ferromagnetic F layer to develop a preferred direction of magnetization, is widely used in magnetoelectronics technology to pin the magnetization of a device reference layer in a desired direction. However, the origin and effects due to exchange interaction across the interface between antiferromagneic and ferromagnetic layers are still debated after about fifty years of research, due to the extreme difficulty associated with the determination of the magnetic interfacial structure in F/AF bilayers. Indeed, in an AF/F bilayer system, the AF layer acts as “the invisible man” during conventional magnetic measurements and the presence of the exchange coupling is evidenced indirectly through the unusual behavior of the adjacent F layer. Basically, the coercive field of the F layer increases in contact with the AF and, in some cases, its hysteresis loop is shifted by an amount called exchange bias field. Thus, AF/F exchange coupling generates a new source of anisotropy in the F layer. This induced anisotropy strongly depends on basic features such as the magnetocrystalline anisotropy, crystallographic and spin structures, defects, domain patterns etc

Spin-locking vs. chemical exchange saturation transfer MRI for investigating chemical exchange process between water and labile metabolite protons

Science.gov (United States)

Jin, Tao; Autio, Joonas; Obata, Takayuki; Kim, Seong-Gi

2010-01-01

Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the exchange process between protons of non-equivalent chemical environments. To compare the characteristics of the CEST and SL approaches in the study of chemical exchange effects, we performed CEST and SL experiments at varied pH and concentrated metabolites with exchangeable amide, amine, and hydroxyl protons at 9.4 T. Our results show that: i) On-resonance SL is most sensitive to chemical exchanges in the intermediate exchange regime and is able to detect hydroxyl and amine protons on a millimolar concentration scale. Off-resonance SL and CEST approaches are sensitive to slow-exchanging protons when an optimal SL or saturation pulse power matches the exchanging rate, respectively. ii) Offset frequency-dependent SL and CEST spectra are very similar, and can be explained well with an SL model recently developed by Trott and Palmer. iii) The exchange rate and population of metabolite protons can be determined from offset-dependent SL or CEST spectra or from on-resonance SL relaxation dispersion measurements. iv) The asymmetry of the magnetization transfer ratio (MTRasym) is highly dependent on the choice of saturation pulse power. In the intermediate exchange regime, MTRasym becomes complicated and should be interpreted with care. PMID:21500270

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4kA was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized herein

Cleaning Schedule Operations in Heat Exchanger Networks

Directory of Open Access Journals (Sweden)

Huda Hairul

2018-01-01

Full Text Available Heat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly.

Ion-Isotopic Exchange Reaction Kinetics using Anion Exchange Resins Dowex 550A LC and Indion-930A

Directory of Open Access Journals (Sweden)

P.U. Singare

2014-06-01

Full Text Available The present paper deals with the characterization of ion exchange resins Dowex 550A LC and Indion-930A based on kinetics of ion-isotopic exchange reactions for which the short lived radioactive isotopes 131I and 82Br were used as a tracers. The study was performed for different concentration of ionic solution varying from 0.001 mol/L to 0.004 mol/L and temperature in the range of 30.0 °C to 45.0 °C. The results indicate that as compared to bromide ion-isotopic exchange reaction, iodide exchange reaction take place at the faster rate. For both the ion-isotopic exchange reactions, under identical experimental conditions, the values of specific reaction rate increases with increase in the ionic concentration and decreases with rise in temperature. It was observed that at 35.00C, 1.000 g of ion exchange resins and 0.002 mol/L labeled iodide ion solution for iodide ion-isotopic exchange reaction, the values of specific reaction rate (min-1, amount of ion exchanged (mmol, initial rate of ion exchange (mmol/min and log Kd were 0.270, 0.342, 0.092 and 11.8 respectively for Dowex 550A LC resin, which was higher than the respective values of 0.156, 0.241, 0.038 and 7.4 as that obtained for Indion-930A resins. From the results, it appears that Dowex 550A LC resins show superior performance over Indion-930A resins under identical experimental conditions.

Towards automatic exchange of information

OpenAIRE

Oberson, Xavier

2015-01-01

This article describes the various steps that led towards automatic exchange of information as the global standard and the issues that remain to be solved. First, the various competing models of exchange information, such as Double Tax Treaty (DTT), TIEA's, FATCA or UE Directives are described with a view to show how they interact between themselves. Second, the so-called Rubik Strategy is summarized and compared with an automatic exchange of information (AEOI). The third part then describes ...

Developing bulk exchange spring magnets

Science.gov (United States)

Mccall, Scott K.; Kuntz, Joshua D.

2017-06-27

A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

Can Exchange Rates Be Predicted?

OpenAIRE

Siriwutiset, Trin

2007-01-01

Foreign exchange rates produce significant impacts on both the macroeconomic and microeconomic scale. Countries� government and multinational companies have been seeking ways to stabilize the exchange rates for a few decades. However, there is no perfect consensus on methods to control and stabilize the exchange rates. In fact, there are several occasions in history where turbulence movements caused crisis in the economies. There are several factors that are identified by economis...

Data Exchange Inventory (DEXI) System

Data.gov (United States)

Social Security Administration — DEXI is an intranet application used by SSA users to track all incoming and outgoing data exchanges between SSA and our data exchange partners. Information such as...

Exchange Rate Pass-Through in Turkey

OpenAIRE

Marco Rossi; Daniel Leigh

2002-01-01

In light of the strong correlation between exchange rate movements and domestic prices in Turkey, it is important to assess the impact of the exchange rate on domestic prices, in particular as Turkey moves to an inflation targeting regime. This paper uses a recursive vector autoregression model to investigate the impact of exchange rate movements on prices in Turkey. We find that (i) the impact of the exchange rate on prices is over after about a year, but is mostly felt in the first four mon...

Ion-exchange properties of natural mordenite

International Nuclear Information System (INIS)

Chelishchev, N.F.; Volodin, V.F.

1977-01-01

Ion exchange properties are studied of natural mordenite Si(Al=4.75) exhibiting adequate mechanical characteristics and sufficient resistance to high temperature acids. Consideration is given to the pattern of exchange ions distribution among mordenite and chloride solutions of K, Cs, Rb, Sr. Mordenite shows sharp selectivity towards large alkali metal cations, particularly Cs + . In these processes the exchange isotherms are characterized by the constant selectivity towards a counterion. For the Sr 2+ -2Na + exchange the isotherm shows a change of selectivity after a definite counterion concentration has been reached in the solution. Correlation between the exchange thermodynamic constants makes it possible to propose the following range of mordenite selectivity towards the cations under study: Cs>Rb>K>Na>Sr

Foreign Exchange Markets in Russia: Understanding the Reforms

OpenAIRE

Linda S. Goldberg

1993-01-01

This paper analyzes and interprets the changes that took place in Russia's exchange rate system during 1992. The multiple exchange rate regime that existed in Russia prior to July 3, 1992, created strong incentives for exporters to refrain from repatriating foreign exchange earnings, induced both importers and exporters to participate in unofficial markets for foreign exchange, and encouraged international barter transactions. Efforts to manage the exchange rate through heavy foreign exchange...

Building Relationships through Exchange

Science.gov (United States)

Primavera, Angi; Hall, Ellen

2011-01-01

From the moment of birth, children form and develop relationships with others in their world based on exchange. Children recognize that engaging in such encounters offers them the opportunity to enter into a relationship with another individual and to nurture that relationship through the exchange of messages and gifts, items and ideas. At Boulder…

47 CFR 90.675 - Information exchange.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Information exchange. 90.675 Section 90.675... exchange. (a) Prior coordination. Public safety/CII licensees may notify an ESMR or part 22 Cellular... cell is activated. (c) Public safety information exchange. (1) Upon request by an ESMR or part 22...

47 CFR 90.555 - Information exchange.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Information exchange. 90.555 Section 90.555...-805 MHz Bands § 90.555 Information exchange. (a) Prior notification. Public safety licensees... Safety Information Exchange. (1) Upon request by a 746-757, 758-763, 776-787, or 788-793 MHz band...

Kinetics of isotopic exchanges by using radioactive indicators

International Nuclear Information System (INIS)

May, S.

1958-12-01

After having noticed that iodine 131 under the form of sodium iodide has always been used as radioactive indicator in the CEA atomic pile located in Chatillon, this research report recalls the counting technique and some historical aspects of the notion of isotopic exchange and qualitative works, and presents some generalities on isotopic exchanges (reactions and calculation of rate constants of order 1 and 2, calculation of activation energy, spectro-photometric studies, Walden inversion, alkaline hydrolysis, influence of solvent on exchange kinetics, influence of the nature of the mineral halide). The author then addresses exchanges in aliphatic series (exchange with sodium iodide and with molecular iodine), exchanges in olefin series, exchanges in alicyclic series, and exchanges in aromatic series

Spin-locking versus chemical exchange saturation transfer MRI for investigating chemical exchange process between water and labile metabolite protons.

Science.gov (United States)

Jin, Tao; Autio, Joonas; Obata, Takayuki; Kim, Seong-Gi

2011-05-01

Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the exchange process between protons of nonequivalent chemical environments. To compare the characteristics of the CEST and SL approaches in the study of chemical exchange effects, we performed CEST and SL experiments at varied pH and concentrated metabolite phantoms with exchangeable amide, amine, and hydroxyl protons at 9.4 T. Our results show that: (i) on-resonance SL is most sensitive to chemical exchanges in the intermediate-exchange regime and is able to detect hydroxyl and amine protons on a millimolar concentration scale. Off-resonance SL and CEST approaches are sensitive to slow-exchanging protons when an optimal SL or saturation pulse power matches the exchanging rate, respectively. (ii) Offset frequency-dependent SL and CEST spectra are very similar and can be explained well with an SL model recently developed by Trott and Palmer (J Magn Reson 2002;154:157-160). (iii) The exchange rate and population of metabolite protons can be determined from offset-dependent SL or CEST spectra or from on-resonance SL relaxation dispersion measurements. (iv) The asymmetry of the magnetization transfer ratio (MTR(asym)) is highly dependent on the choice of saturation pulse power. In the intermediate-exchange regime, MTR(asym) becomes complicated and should be interpreted with care. Copyright © 2010 Wiley-Liss, Inc.

Foreign Exchange Risk in International Transactions

Directory of Open Access Journals (Sweden)

Florentina-Olivia Balu

2007-03-01

In this article we will focus on forward and futures contracts for managing foreign exchange risk. A forward is a contract to buy or sell currency at an agreed upon exchange rate at a specific date in the future. Futures are similar to forwards except that they’re traded on exchanges which specify settlement dates. Also we make some recommendations related to the foreign exchange risk-management practices that are useful for companies involved in international trade and for financial institutions interested in providing hedging products to these companies.

Application of ion exchange processes for the treatment of radioactive waste and management of spent ion exchangers

International Nuclear Information System (INIS)

2002-01-01

This report describes the ion exchange technologies currently used and under development in nuclear industry, in particular for waste management practices, along with the experience gained in their application and with the subsequent handling, treatment and conditioning of spent ion exchange media for long term storage and/or disposal. The increased role of inorganic ion exchangers for treatment of radioactive liquid waste, both in nuclear power plant operations and in the fuel reprocessing sector, is recognised in this report. The intention of this report is to consolidate the previous publications, document recent developments and describe the state of the art in the application of ion exchange processes for the treatment of radioactive liquid waste and the management of spent ion exchange materials

Data Exchange Protocol in Repsail

Directory of Open Access Journals (Sweden)

Gucma Maciej

2017-12-01

Full Text Available Article presents implantation and theoretical considerations of data exchange protocol developed for the RepSail project, where main objective was design and building innovative hybrid yacht. One of problems during the design process was improper functioning of data exchange protocols that were available in the commercially available devices to mention navigation purpose NMEA183 or 2000 as well as automation dedicated ones (CAN and similar. Author shows the basis of the dedicated format of exchange for in board devices.

Cryogenic Heat Exchanger with Turbulent Flows

Science.gov (United States)

Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

2012-01-01

An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

Ion exchange resins as high-dose radiation dosimeters

International Nuclear Information System (INIS)

Alian, A.; Dessouki, A.; El-Assay, N.B.

1984-01-01

This paper reports on the possibility of using various types of ion exchange resins as high-dose radiation dosimeters, by analysis of the decrease in exchange capacity with absorbed dose. The resins studied are Sojuzchim-export-Moscow Cation Exchanger KU-2 and Anion Exchanger AV-17 and Merck Cation Exchanger I, and Merck Anion Exchangers II and III. Over the dose range 1 to 100 kGy, the systems show linearity between log absorbed dose and decrease in resin ion exchange capacity. The slope of this response function differs for the different resins, depending on their ionic form and degree of cross-linking. The radiation sensitivity increases in the order KU-2; Exchanger I; AV-17; Exchanger II; Exchanger III. Merck resins with moisture content of 21% showed considerably higher radiation sensitivity than those with 2 to 3% moisture content. The mechanism of radiation-induced denaturing of the ion exchanger resins involves cleavage and decomposition of functional substituents, with crosslinking playing a stabilizing role, with water and its radiolytic products serving to inhibit radical recombination and interfering with the protection cage effect of crosslinking. (author)

Multiprocessor shared-memory information exchange

International Nuclear Information System (INIS)

Santoline, L.L.; Bowers, M.D.; Crew, A.W.; Roslund, C.J.; Ghrist, W.D. III

1989-01-01

In distributed microprocessor-based instrumentation and control systems, the inter-and intra-subsystem communication requirements ultimately form the basis for the overall system architecture. This paper describes a software protocol which addresses the intra-subsystem communications problem. Specifically the protocol allows for multiple processors to exchange information via a shared-memory interface. The authors primary goal is to provide a reliable means for information to be exchanged between central application processor boards (masters) and dedicated function processor boards (slaves) in a single computer chassis. The resultant Multiprocessor Shared-Memory Information Exchange (MSMIE) protocol, a standard master-slave shared-memory interface suitable for use in nuclear safety systems, is designed to pass unidirectional buffers of information between the processors while providing a minimum, deterministic cycle time for this data exchange

[To exercise caution in developing intraocular lens exchange].

Science.gov (United States)

Song, X D; Wang, X Z; Qian, J

2018-05-11

Nowadays cataract extraction combined intraocular lens (IOL) implantation has become the conventional treatment for cataract. Numbers of IOL exchange after cataract extraction combined IOL implantation have been increasing in recent years. As a non-routine surgery, IOL exchange is normally combined with other surgeries and accompanied by some complications to various extents. Is IOL exchange necessary for all abnomal IOLs? Can IOL exchange be avoided? How to avoid IOL exchange? The purpose of this article is to stress the importance of indication of IOL exchange and how to avoid IOL exchange. (Chin J Ophthalmol, 2018, 54: 324-327) .

Chemical uranium enrichment with ion exchanger

International Nuclear Information System (INIS)

Takeda, Kunihiko; Onitsuka, Hatsuki; Obanawa, Heiichiro

1991-01-01

The uranium enrichment by using ion-exchange has been studied and developed since 1972. The ion-exchange rate has been improved approx. 3000 times and the electron exchange reaction, which occurs with ion-exchange reaction, was also accelerated with catalyst. Flow disturbance in a ion-exchange column has been fully studied and the value of turbulence has been reduced to 150μm. These results allowed us to design a very fine separation column, in which about 10000 stages can be obtained even when the column is more than 1 m in diameter. In the course of the development, a self-regenerating reaction between the redox agents was discovered and incorporated into the process, and has resulted in a reduction of 70 % in the separation energy requirement. (author)

Studies on indigenous ion exchange resins: alkali metal ions-hydrogen ion exchange equilibria

International Nuclear Information System (INIS)

Shankar, S.; Kumar, Surender; Venkataramani, B.

2001-01-01

With a view to select a suitable ion exchange resin for the removal of radionuclides (such as cesium, strontium etc.) from low level radioactive effluents, alkali metal ion -H' exchanges on nine indigenous gel- and macroporous-type and nuclear grade resins have been studied at a total ionic strength of 0.1 mol dm .3 (in the case ofCs' -H' exchange it was 0.05 mol dm .3 ). The expected theoretical capacities were not attained by all the resins for the alkali metal ions. The water content (moles/equiv.) of the fully swollen resins for different alkali metal ionic forms do not follow the usual sequence of greater the tendency of the cation to hydrate the higher the water uptake, but a reverse trend. The ion exchange isotherms (plots of equivalent fractions of the ion in resin phase, N M1 to that in solution, N M ) were not satisfactory and sorption of cations, for most of the resins, was possible only when the acidity of the solution was lowered. The variations of the selectivity coefficient, K, with N M show that the resins are highly cross linked and the selectivity sequence: Cs + >K + >Na + >Li + , obtained for all the resins indicate that hydrated ions were involved in the exchange process. However, the increase in the selectivity was not accompanied by the release of water, but unusual uptake of water, during the exchange process. The characteristics of macroporous resins were not significantly different from those of the gel-type resins. The results are discussed in terms of heterogeneity in the polymer net work, improper sulphonation process resulting in the formation of functional groups at inaccessible sites with weak acidic character and the overall lack of control in the preparation of different resins. (author)

Listening to agent agendas in student exchanges

DEFF Research Database (Denmark)

Tarp, Gertrud

2003-01-01

The paper is based upon a research study of short-term student exchanges. The study took place from 1996-2000, and comprises seven classes of students from six Danish business schools. Short-term student exchanges in terms of EU funded exchanges and local school exchanges are means to develop...... institutional scepticism and placed within the theoretical framework of symbolic interactionism. The methodology applied is qualitative, grounded theory, and the data originate from diaries, semi-structured interviews and semi-open questionnaires. The findings show that the students have their own exchange...

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein

Neighbourhood Book Exchanges: Localising Information Practices

Science.gov (United States)

Webster, Tenny; Gollner, Kathleen; Nathan, Lisa

2015-01-01

Introduction: Through this paper we report on an exploratory study into the design and use of neighbourhood book exchanges in North America. We identify dominant media framings of these book exchanges in North America, along with claims made concerning the influence of the exchanges. We compare the media claims with insights from interviews with…

Cross-Market Linkages of Taiwan Index Futures Contracts Listed on the Taiwan Futures Exchange and the Singapore Exchange

OpenAIRE

Hung-Gay Fung; Qingfeng "Wilson" Liu; Gyoungsin "Daniel" Park

2007-01-01

Cointegration tests and ex ante trading rules are applied to study cross-market linkages between the Taiwan Index futures contracts listed on the Singapore Exchange and the Taiwan Stock Exchange Capitalization-weighted Stock Index futures contracts listed on the Taiwan Futures Exchange. The exchange rate-adjusted returns of the two futures series do not differ significantly in mean but in variances, and show significant mean-reverting tendencies between them. Our trading strategies are able t...

Calmodulin-lanthanide ion exchange kinetics

International Nuclear Information System (INIS)

Buccigross, J.; O'Donnell, C.; Nelson, D.

1985-01-01

A flow dialysis apparatus suitable for the study of high affinity metal binding proteins has been utilized to study calmodulin-metal exchange kinetics. Calmodulin labeled with Eu-155 and Gd-153 was dialyzed against buffer containing various competing metal ions. The rate of metal exchange was monitored by a gamma-ray scintillation detector. The kinetics of exchange are first order, and the rates fall into two categories: Ca (II) and CD (II) in one, and the lanthanides Eu (III), Gd (III), and La (III) in the other

Ion-exchange equilibrium of N-acetyl-D-neuraminic acid on a strong anionic exchanger.

Science.gov (United States)

Wu, Jinglan; Ke, Xu; Zhang, Xudong; Zhuang, Wei; Zhou, Jingwei; Ying, Hanjie

2015-09-15

N-acetyl-D-neuraminic acid (Neu5Ac) is a high value-added product widely applied in the food industry. A suitable equilibrium model is required for purification of Neu5Ac based on ion-exchange chromatography. Hence, the equilibrium uptake of Neu5Ac on a strong anion exchanger, AD-1 was investigated experimentally and theoretically. The uptake of Neu5Ac by the hydroxyl form of the resin occurred primarily by a stoichiometric exchange of Neu5Ac(-) and OH(-). The experimental data showed that the selectivity coefficient for the exchange of Neu5Ac(-) with OH(-) was a non-constant quantity. Subsequently, the Saunders' model, which took into account the dissociation reactions of Neu5Ac and the condition of electroneutrality, was used to correlate the Neu5Ac sorption isotherms at various solution pHs and Neu5Ac concentrations. The model provided an excellent fit to the binary exchange data for Cl(-)/OH(-) and Neu5Ac(-)/OH(-), and an approximate prediction of equilibrium in the ternary system Cl(-)/Neu5Ac(-)/OH(-). This basic information combined with the general mass transfer model could lay the foundation for the prediction of dynamic behavior of fixed bed separation process afterwards. Copyright © 2015 Elsevier Ltd. All rights reserved.

Operating revenue changes in a demutualized stock exchange

Directory of Open Access Journals (Sweden)

Mohamed Hesham Abdel-Hafez

2015-03-01

Full Text Available Stock exchanges were traditionally run as cooperative venues. The globalization, the development of technology, and the increase of competition among stock exchanges forced these venues to change their structure and adopt a new one-demutualization- that can be a lifeline in facing these environmental changes in regards to stock exchanges. This new trend enables the exchange to expand their activities and supply the market with new products and services, therefore enhancing the value of the exchange itself. The main sources of revenue for traditional exchanges have been listing fees, transaction fees, membership fees and the sale of information services such as market data, quotations, and trade data. Due to the environmental changes the stock exchanges' services are now executed electronically, and in turn, this has led to an increase in the competition among exchanges. Furthermore, this increased competition has led to the re-adjustment of the regulation structure which gradually erodes the sources of revenues provided by the conventional stock exchanges. The paper divided the research plan into two sections: the first section is to highlight the concept of demutualization process; the phases of demutualization, the factors that push the stock exchanges to demutualize and the benefits of demutualization. The second section was based on statistical comparative analysis of the stock exchanges' revenues prior and after demutualization. The researcher used the regression analysis tool on seven demutualized stock exchanges during the period from 1997-2012. The paper aims to prove that demutualization has a positive effect on the revenues of the stock exchange, thus it enhances the value of the exchange.

Plasma exchange for Guillain-Barré syndrome.

Science.gov (United States)

Raphaël, J C; Chevret, S; Hughes, R A; Annane, D

2002-01-01

Guillain-Barré syndrome is an acute symmetric, usually ascending and usually paralysing illness, due to inflammation of peripheral nerves. It is thought to be caused by autoimmune factors, such as antibodies. Plasma exchange removes antibodies and other potentially injurious factors from the blood stream. It involves connecting the patient's blood circulation to a machine which exchanges the plasma for a substitute solution, usually albumin. Several studies have evaluated plasma exchange for Guillain-Barré syndrome. To systematically review the evidence concerning the efficacy of plasma exchange for treating Guillain-Barré syndrome. Search of the Cochrane Neuromuscular Disease Trial Register for randomised trials concerning plasma exchange in Guillain-Barré syndrome, search of the bibliographies of identified papers and enquiry from the authors of the papers. Randomised and quasi-randomised trials of plasma exchange versus sham exchange or supportive treatment. Potentially relevant papers were scrutinised by two reviewers and the selection of eligible studies was agreed by them and a third reviewer. Data were extracted by one reviewer and checked by a second reviewer. Some missing data were obtained from the authors of studies. Six eligible trials concerning 649 patients were identified, all comparing plasma exchange versus supportive treatment alone. Primary outcome measures ~bullet~Time to recover walking with aid In the only two trials for which this measure was reported, the median time to recover this ability was faster in the plasma exchange than the control group. ~bullet~Time to onset of motor recovery in mildly affected patients In the one trial for which this measure was available, the time was significantly shortened in the plasma exchange group. Secondary outcome measures ~bullet~Improvement in disability grade at four weeks In five trials, there were significantly more patients who had improved by one disability grade or more in the plasma exchange

Exchange Network

Science.gov (United States)

The Environmental Information Exchange Network (EN) is an Internet-based system used by state, tribal and territorial partners to securely share environmental and health information with one another and EPA.

Afterglow Imaging and Polarization of Misaligned Structured GRB Jets and Cocoons: Breaking the Degeneracy in GRB 170817A

Science.gov (United States)

Gill, Ramandeep; Granot, Jonathan

2018-05-01

The X-ray to radio afterglow emission of GRB 170817A / GW 170817 so far scales as Fν∝ν-0.6t0.8 with observed frequency and time, consistent with a single power-law segment of the synchrotron spectrum from the external shock going into the ambient medium. This requires the effective isotropic equivalent afterglow shock energy in the visible region to increase as ˜t1.7. The two main channels for such an energy increase are (i) radial: more energy carried by slower material (in the visible region) gradually catches up with the afterglow shock and energizes it, and (ii) angular: more energy in relativistic outflow moving at different angles to our line of sight, whose radiation is initially beamed away from us but its beaming cone gradually reaches our line of sight as it decelerates. One cannot distinguish between these explanations (or combinations of them) using only the X-ray to radio Fν(t). Here we demonstrate that the most promising way to break this degeneracy is through afterglow imaging and polarization, by calculating the predicted evolution of the afterglow image (its size, shape and flux centroid) and linear polarization Π(t) for different angular and/or radial outflow structures that fit Fν(t). We consider two angular profiles - a Gaussian and a narrow core with power-law wings in energy per solid angle, as well as a (cocoon motivated) (quasi-) spherical flow with radial velocity profile. For a jet viewed off-axis (and a magnetic field produced in the afterglow shock) Π(t) peaks when the jet's core becomes visible, at ≈2tp where the lightcurve peaks at tp, and the image can be elongated with aspect ratios ≳ 2. A quasi-spherical flow has an almost circular image and a much lower Π(t) (peaking at ≈tp) and flux centroid displacement θfc (a spherical flow has Π(t) = θfc = 0 and a perfectly circular image).

Essential Specification Elements for Heat Exchanger Replacement

Energy Technology Data Exchange (ETDEWEB)

Bower, L.

2015-07-01

Performance upgrade and equipment degradation are the primary impetuses for a nuclear power plant to engage in the large capital cost project of heat exchanger replacement. Along with attention to these issues, consideration of heat exchanger Codes and Standards, material improvements, thermal redesign, and configuration are essential for developing User’s Design Specifications for successful replacement projects. The User’s Design Specification is the central document in procuring ASME heat exchangers. Properly stated objectives for the heat exchanger replacement are essential for obtaining the materials, configurations and thermal designs best suited for the nuclear power plant. Additionally, the code of construction required and the applied manufacturing standard (TEMA or HEI) affects how the heat exchanger may be designed or configured to meet the replacement goals. Knowledge of how Codes and Standards affect design and configuration details will aid in writing the User’s Design Specification. Joseph Oat Corporation has designed and fabricated many replacement heat exchangers for the nuclear power industry. These heat exchangers have been constructed per ASME Section III to various Code-Years or ASME Section VIII-1 to the current Code-Year also in accordance with TEMA and HEI. These heat exchangers have been a range of like-for-like replacement to complete thermal, material and configuration redesigns. Several examples of these heat exchangers with their Code, Standard and specification implications are presented. (Author.

Tokamak rotation and charge exchange

International Nuclear Information System (INIS)

Hazeltine, R.D.; Rowan, W.L.; Solano, E.R.; Valanju, P.M.

1991-01-01

In the absence of momentum input, tokamak toroidal rotation rates are typically small - no larger in particular than poloidal rotation - even when the radial electric field is strong, as near the plasma edge. This circumstance, contradicting conventional neoclassical theory, is commonly attributed to the rotation damping effect of charge exchange, although a detailed comparison between charge-exchange damping theory and experiment is apparently unavailable. Such a comparison is attempted here in the context of recent TEXT experiments, which compare rotation rates, both poloidal and toroidal, in helium and hydrogen discharges. The helium discharges provide useful data because they are nearly free of ion-neutral charge exchange; they have been found to rotate toroidally in reasonable agreement with neoclassical predictions. The hydrogen experiments show much smaller toroidal motion as usual. The theoretical calculation uses the full charge-exchange operator and assumes plateau collisionality, roughly consistent with the experimental conditions. The authors calculate the ion flow as a function of v cx /v c , where v cx is the charge exchange rate and v c the Coulomb collision frequency. The results are in reasonable accord with the observations. 1 ref

77 FR 24752 - Self-Regulatory Organizations; EDGA Exchange, Inc.; EDGX Exchange, Inc.; International Securities...

Science.gov (United States)

2012-04-25

... Securities Holdings, Inc. (``ISE Holdings'') to a newly formed Swiss corporation, Eurex Global Derivatives AG... SECURITIES AND EXCHANGE COMMISSION [Release No. 34-66834; File Nos. SR-EDGA-2012-08; SR-EDGX-2012....; International Securities Exchange, LLC; Order Granting Approval of Proposed Rule Change Relating to a Corporate...

Social power in exchange theories: Homans's and Blau's considerations of the relationship between the power and the exchange

OpenAIRE

Mentus, Vladimir

2014-01-01

Since social exchange is one of the key concepts in the social life, the exchange theory can be one of the most important within sociology. Also, another crucial concept to the social reality and social sciences is social power. The theory of social exchange has provided a significant contribution to the study of power, however, this contribution of theorists who belong to exchange paradigm is completely neglected within scientific literature. Therefore, the subject of this paper is social po...

Exchangers man the pumps: Functional interplay between proton pumps and proton-coupled Ca exchangers.

Science.gov (United States)

Barkla, Bronwyn J; Hirschi, Kendal D; Pittman, Jon K

2008-05-01

Tonoplast-localised proton-coupled Ca(2+) transporters encoded by cation/H(+)exchanger (CAX) genes play a critical role in sequestering Ca(2+) into the vacuole. These transporters may function in coordination with Ca(2+) release channels, to shape stimulus-induced cytosolic Ca(2+) elevations. Recent analysis of Arabidopsis CAX knockout mutants, particularly cax1 and cax3, identified a variety of phenotypes including sensitivity to abiotic stresses, which indicated that these transporters might play a role in mediating the plant's stress response. A common feature of these mutants was the perturbation of H(+)-ATPase activity at both the tonoplast and the plasma membrane, suggesting a tight interplay between the Ca(2+)/H(+) exchangers and H(+) pumps. We speculate that indirect regulation of proton flux by the exchangers may be as important as the direct regulation of Ca(2+) flux. These results suggest cautious interpretation of mutant Ca(2+)/H(+) exchanger phenotypes that may be due to either perturbed Ca(2+) or H(+) transport.

Isotope exchange reaction of tritium on precious metal catalyst based on cation-exchanged mordenite for blanket tritium recovery

Energy Technology Data Exchange (ETDEWEB)

Kawamura, Yoshinori, E-mail: kawamura.yoshinori@jaea.go.jp [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Hayashi, Takumi [Japan Atomic Energy Agency, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195 (Japan); Yamanishi, Toshihiko [Japan Atomic Energy Agency, 2-166 Omotedate Obuchi, Rokkasho, Aomori 039-3212 (Japan)

2016-11-01

Highlights: • Precious metal catalyst based on cation-exchanged mordenite was prepared. • Isotope exchange reaction between H{sub 2} and HTO on the catalyst was investigated. • The order of entire reaction is not clear, but it is the first-order reaction as for HTO. • Effect of exchanged cation may appear as the difference of the surface area of catalyst. - Abstract: It is known that the chemical forms of tritium released from a ceramic breeder blanket are hydrogen form and water form. To recover tritiated water vapor, adoption of dryer that is packed column of synthetic zeolite has been proposed. On the other hand, synthetic zeolite is often used as a support of precious metal catalyst. Such catalysts usually have a capability of hydrogen isotope exchange between gas and water vapor. If this catalyst is used to dryer, the dryer may obtain a preferable function for tritium recovery by isotopic exchange reaction. To assess such functions, reaction rate should be estimated. The results of water adsorption experiment on cation-exchanged mordenite-type zeolite suggested the possibility that state of adsorbed water varied by exchanged cation. So, in this work, precious metal catalyst based on cation-exchanged mordenite was prepared, and the reaction rate of chemical exchange between hydrogen and tritiated water was investigated under temperature range between 30 °C and 80 °C by the steady-state approximation. In the case of platinum on Na-mordenite, the reaction between gaseous hydrogen and tritiated water vapor was almost expressed as first-order reaction concerning tritiated water vapor concentration.

Test procedure for anion exchange chromatography

International Nuclear Information System (INIS)

Cooper, T.D.

1994-01-01

Plutonium from stored nitrate solutions will be sorbed onto anion exchange resins and converted to storable plutonium dioxide. Useful information will be simultaneously gained on the thermal stability and ion exchange capacity of four commercially available anion exchange resins over several years and under severe degradative conditions. This information will prove useful in predicting the safe and efficient lifetimes of these resins

Chapter 11. Heat Exchangers

Energy Technology Data Exchange (ETDEWEB)

Rafferty, Kevin D.; Culver, Gene

1998-01-01

Most geothermal fluids, because of their elevated temperature, contain a variety of dissolved chemicals. These chemicals are frequently corrosive toward standard materials of construction. As a result, it is advisable in most cases to isolate the geothermal fluid from the process to which heat is being transferred. The task of heat transfer from the geothermal fluid to a closed process loop is most often handled by a plate heat exchanger. The two most common types used in geothermal applications are: bolted and brazed. For smaller systems, in geothermal resource areas of a specific character, downhole heat exchangers (DHEs) provide a unique means of heat extraction. These devices eliminate the requirement for physical removal of fluid from the well. For this reason, DHE-based systems avoid entirely the environmental and practical problems associated with fluid disposal. Shell and tube heat exchangers play only a minor role in low-temperature, direct-use systems. These units have been in common use in industrial applications for many years and, as a result, are well understood. For these reasons, shell and tube heat exchangers will not be covered in this chapter.

Exchange-rate forecasts and asymmetric loss: empirical evidence for the yen/dollar exchange rate

DEFF Research Database (Denmark)

Stadtmann, Georg; Pierdzioch; Rülke

2012-01-01

We used the yen/dollar exchange-rate forecasts of the Wall Street Journal (WSJ) poll to analyse whether exchange-rate forecasters have an asymmetric loss function. To this end, we applied an approach recently developed by Elliott et al. (2005). We found that only few forecasters seem to form...

A Case for Intermediate Exchange-Rate Regimes

OpenAIRE

Agnès Bénassy-Quéré; Véronique Salins

2010-01-01

Despite increasing capital mobility and the subsequent difficulty in controlling exchange rates, intermediate exchange-rate regimes have remained widespread, especially in emerging and developing economies. This piece of evidence hardly fits the "impossible Trinity" theory arguing that it becomes difficult to control the exchange rate without a "hard" device when capital flows are freed. Calvo and Reinhart (2000) have suggested several explanations for such "fear of floating": exchange rate p...

On the mechanism of ion exchange in zirconium phosphates

International Nuclear Information System (INIS)

Kullberg, L.; Clearfield, A.

1981-01-01

An equilibrium study of the Na + -Cs + -H + exchange on crystalline α-zirconium phosphate has been carried out. Isotherms for the ion exchange have been determined and phases formed during the exchange have been identified. The surface groups of the exchanger were found to greatly prefer cesium to sodium. For exchange in the interior, cesium was found to be preferred to sodium for 0 to 50% of exchange, while sodium is slightly preferred to cesium for the second half of exchange. The influence of surface equilibria on the total exchange mechanism is discussed. (author)

Real exchange rate misalignments

OpenAIRE

Terra, Maria Cristina T.; Valladares, Frederico Estrella Carneiro

2003-01-01

This paper characterizes episodes of real appreciations and depreciations for a sample of 85 countries, approximately from 1960 to 1998. First, the equilibrium real exchange rate series are constructed for each country using Goldfajn and Valdes (1999) methodology (cointegration with fundamentals). Then, departures from equilibrium real exchange rate (misalignments) are obtained, and a Markov Switching Model is used to characterize the misalignments series as stochastic autor...

Power decreases trust in social exchange.

Science.gov (United States)

Schilke, Oliver; Reimann, Martin; Cook, Karen S

2015-10-20

How does lacking vs. possessing power in a social exchange affect people's trust in their exchange partner? An answer to this question has broad implications for a number of exchange settings in which dependence plays an important role. Here, we report on a series of experiments in which we manipulated participants' power position in terms of structural dependence and observed their trust perceptions and behaviors. Over a variety of different experimental paradigms and measures, we find that more powerful actors place less trust in others than less powerful actors do. Our results contradict predictions by rational actor models, which assume that low-power individuals are able to anticipate that a more powerful exchange partner will place little value on the relationship with them, thus tends to behave opportunistically, and consequently cannot be trusted. Conversely, our results support predictions by motivated cognition theory, which posits that low-power individuals want their exchange partner to be trustworthy and then act according to that desire. Mediation analyses show that, consistent with the motivated cognition account, having low power increases individuals' hope and, in turn, their perceptions of their exchange partners' benevolence, which ultimately leads them to trust.

Giant exchange interaction in mixed lanthanides

Science.gov (United States)

Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

2016-01-01

Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction. PMID:27087470

Incentive compatibility in kidney exchange problems.

Science.gov (United States)

Villa, Silvia; Patrone, Fioravante

2009-12-01

The problem of kidney exchanges shares common features with the classical problem of exchange of indivisible goods studied in the mechanism design literature, while presenting additional constraints on the size of feasible exchanges. The solution of a kidney exchange problem can be summarized in a mapping from the relevant underlying characteristics of the players (patients and their donors) to the set of matchings. The goal is to select only matchings maximizing a chosen welfare function. Since the final outcome heavily depends on the private information in possess of the players, a basic requirement in order to reach efficiency is the truthful revelation of this information. We show that for the kidney exchange problem, a class of (in principle) efficient mechanisms does not enjoy the incentive compatibility property and therefore is subject to possible manipulations made by the players in order to profit of the misrepresentation of their private information.

Exchange rate regimes and monetary arrangements

Directory of Open Access Journals (Sweden)

Ivan Ribnikar

2005-06-01

Full Text Available There is a close relationship between a country’s exchange rate regime and monetary arrangement and if we are to examine monetary arrangements then exchange rate regimes must first be analysed. Within the conventional and most widely used classification of exchange rate regimes into rigid and flexible or into polar regimes (hard peg and float on one side, and intermediate regimes on the other there, is a much greater variety among intermediate regimes. A more precise and, as will be seen, more useful classification of exchange rate regimes is the first topic of the paper. The second topic is how exchange rate regimes influence or determine monetary arrangements and monetary policy or monetary policy regimes: monetary autonomy versus monetary nonautonomy and discretion in monetary policy versus commitment in monetary policy. Both topics are important for countries on their path to the EU and the euro area

Effects of ionizing radiation on modern ion exchange materials

International Nuclear Information System (INIS)

Marsh, S.F.; Pillay, K.K.S.

1993-10-01

We review published studies of the effects of ionizing radiation on ion exchange materials, emphasizing those published in recent years. A brief overview is followed by a more detailed examination of recent developments. Our review includes styrene/divinylbenzene copolymers with cation-exchange or anion-exchange functional groups, polyvinylpyridine anion exchangers, chelating resins, multifunctional resins, and inorganic exchangers. In general, strong-acid cation exchange resins are more resistant to radiation than are strong-base anion exchange resins, and polyvinylpyridine resins are more resistant than polystyrene resins. Cross-linkage, salt form, moisture content, and the surrounding medium all affect the radiation stability of a specific exchanger. Inorganic exchangers usually, but not always, exhibit high radiation resistance. Liquid ion exchangers, which have been used so extensively in nuclear processing applications, also are included

Exchange interactions in Fe/Y multilayers

International Nuclear Information System (INIS)

Elkabil, R.; Elkaidi, I.; Annouar, F.; Lassri, H.; Hamdoun, A.; Bensassi, B.; Berrada, A.; Krishnan, R.

2005-01-01

The magnetization of Fe/Y multilayers has been measured as a function of temperature. A bulk-like T 3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5-300 K. The spin-wave constant B is found to decrease inversely with t Fe . A simple theoretical model with exchange interactions only, and with non-interacting magnons, has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J b , surface exchange interaction J s and the interlayer exchange interaction J I for various Fe layer thicknesses have been obtained

Tear exchange and contact lenses: a review.

Science.gov (United States)

Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

2015-01-01

Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Diffie-Hellman Key Exchange through Steganographied Images

Directory of Open Access Journals (Sweden)

Amine Khaldi

2018-05-01

Full Text Available Purpose – In a private key system, the major problem is the exchange of the key between the two parties. Diffie and Hellman have set up a way to share the key. However, this technique is not protected against a man-in-the-middle attack as the settings are not authenticated. The Diffie-Hellman key exchange requires the use of digital signature or creating a secure channel for data exchanging to avoid the man-in-the-middle attack. Methodology/approach/design – We present a Diffie-Hellman key exchange implementation using steganographied images. Using steganography made invisible the data exchange to a potential attacker. So, we will not need a digital signature or creating a secure channel to do our key exchange since only the two concerned parts are aware of this exchange. Findings – We generate a symmetric 128-bit key between two users without use of digital signature or secure channel. However, it works only on bitmap images, heavy images and sensitive to compression.

Gadolinium-hydrogen ion exchange of zirconium phosphate

Science.gov (United States)

Liu, D. C.; Power, J. L.

1972-01-01

The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

Optimization of parameters of heat exchangers vehicles

Directory of Open Access Journals (Sweden)

Andrei MELEKHIN

2014-09-01

Full Text Available The relevance of the topic due to the decision of problems of the economy of resources in heating systems of vehicles. To solve this problem we have developed an integrated method of research, which allows to solve tasks on optimization of parameters of heat exchangers vehicles. This method decides multicriteria optimization problem with the program nonlinear optimization on the basis of software with the introduction of an array of temperatures obtained using thermography. The authors have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem and check its adequacy to the experimental stand in the visualization of thermal fields, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger vehicles, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model.

Mechanical calculation of heat exchangers

International Nuclear Information System (INIS)

Osweiller, Francis.

1977-01-01

Many heat exchangers are still being dimensioned at the present time by means of the American TEMA code (Tubular Exchanger Manufacturers Association). The basic formula of this code often gives rise to significant tubular plate thicknesses which, apart from the cost of materials, involve significant machining. Some constructors have brought into use calculation methods that are more analytic so as to take into better consideration the mechanical phenomena which come into play in a heat exchanger. After a brief analysis of these methods it is shown, how the original TEMA formulations have changed to reach the present version and how this code has incorporated Gardner's results for treating exchangers with two fixed heads. A formal and numerical comparison is then made of the analytical and TEMA methods by attempting to highlight a code based on these methods or a computer calculation programme in relation to the TEMA code [fr

Method of pyrolysis for spent ion-exchange resins

International Nuclear Information System (INIS)

Aoyama, Yoshiyuki; Matsuda, Masami; Kawamura, Fumio; Yusa, Hideo.

1985-01-01

Purpose: To prevent the generation of noxious sulfur oxide and ammonia on the pyrolysis for spent ion-exchange resins discharged from nuclear power plants. Method: In the case where the pyrolysis is made for the cationic exchange resins having sulfonic acids as the ion-exchange group, alkali metals or alkaline earth metals capable of reacting with sulfonic acid groups to form solid sulfates are previously deposited by way of ion-exchange reactions prior to the pyrolysis. In another case of the anionic exchange resins having quarternary ammonium groups as the ion-exchange groups, halogenic elements capable of reacting with the ammonium groups to form solid ammonium salts are deposited to the ion-exchange resins through ion-exchange reactions prior to the pyrolysis. As a result, the amount of the binders used can be reduced, and this method can be used in a relatively simple processing facility. (Horiuchi, T.)

The electricity exchange. On the organisation and latent functions of electricity exchange trading as seen from the viewpoint of market sociology

International Nuclear Information System (INIS)

Giacovelli, Sebastian

2014-01-01

Electricity exchange trading in Germany has existed since the year 2000. Since this time, the Leipzig electricity exchange, a reference market for off-exchange electricity trading, has operated in an environment marked by both criticism and acceptance. Taking this field of controversy as a point of departure the present empirical study in market sociology undertakes to investigate the organisation and latent functions of electricity exchange trading. The ensuing analysis provides answers to questions as to how prices are formed on the electricity exchange and what officially incommunicable functions are served by price formation on exchanges.

Essays on Stock Exchange Competition and Pricing

OpenAIRE

Andersen, Atso

2005-01-01

This study deals with the industrial structure, the nature of competition and the pricing of stock exchange trading services in Europe. Specific for the study is that exchanges are considered to be profit-maximizing institutions that face competition. A conventional analysis of concentration ratios shows that the concentration of European stock exchanges is low. When the nature of competition is measured in more detail, regression results indicate that exchanges operate in monopolistic o...

Studies of the hydrous titanium oxide ion exchanger. 4. Rate of the isotopic exchange of sodium ions between the exchanger in the Na+ form and aqueous solution

International Nuclear Information System (INIS)

Inoue, Yasushi; Yamazaki, Hiromichi; Kasuga, Fuminori

1995-01-01

The isotopic exchange rate of Na + between hydrous titanium(IV) oxides, precipitated at pH 6 and 13, in the Na + form and aqueous solution of sodium salt was determined radiochemically. The rate in the exchanger precipitated at pH 6 is controlled by the diffusion of Na + in the exchanger particles (particle diffusion). The diffusion coefficient and its activation energy are 1.9 x 10 -11 m 2 s -1 (pH 12, 5.0degC) and 29 kJ mol -1 (pH 12), respectively. The rate in the exchanger precipitated at pH 13 is also controlled by the particle diffusion. The rate is much slower than that in the other; this can be explained by assuming the existence of two kinds of independently diffusing ions (fast and slow species) in the exchanger. The diffusion coefficients are of the order of 10 -12 and 10 -13 m 2 s -1 for the fast and the slow species, respectively. Their activation energies are 48-60 kJ mol -1 at pH 12. The marked difference in kinetics between two exchanges was interpreted in terms of the difference in the acid-base property and in the microstructure of the matrix. (author)

Relational and XML Data Exchange

CERN Document Server

Arenas, Marcelo

2010-01-01

Data exchange is the problem of finding an instance of a target schema, given an instance of a source schema and a specification of the relationship between the source and the target. Such a target instance should correctly represent information from the source instance under the constraints imposed by the target schema, and it should allow one to evaluate queries on the target instance in a way that is semantically consistent with the source data. Data exchange is an old problem that re-emerged as an active research topic recently, due to the increased need for exchange of data in various for

Corrosion protected reversing heat exchanger

International Nuclear Information System (INIS)

Zawierucha, R.

1984-01-01

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

Heat exchanger using graphite foam

Science.gov (United States)

Campagna, Michael Joseph; Callas, James John

2012-09-25

A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

Organic decontamination by ion exchange

International Nuclear Information System (INIS)

Wilson, T.R.

1994-01-01

This study has successfully identified ion exchanger media suitable for decontaminating the 5500-gallon organic layer in Tank 241-C-103. Decontamination of radionuclides is necessary to meet shipping, incinerator site storage, and incineration feed requirements. The exchanger media were identified through a literature search and experiments at the Russian Institute for Physical Chemistry. The principal radionuclides addressed are Cs-137 and Sr-90. Recommendations for an experimental program plan conclude the discussion. The experimental program would provide the data necessary for plant design specifications for a column and for ion exchange media to be used in decontaminating the organic layer

Fair Exchange in Strand Spaces

Directory of Open Access Journals (Sweden)

Joshua D. Guttman

2009-10-01

Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

Argentina's experience with parallel exchange markets: 1981-1990

OpenAIRE

Steven B. Kamin

1991-01-01

This paper surveys the development and operation of the parallel exchange market in Argentina during the 1980s, and evaluates its impact upon macroeconomic performance and policy. The historical evolution of Argentina's exchange market policies is reviewed in order to understand the government's motives for imposing exchange controls. The parallel exchange market engendered by these controls is then analyzed, and econometric methods are used to evaluate the behavior of the parallel exchange r...

KRW/USD Exchange Rate Volatility and Efficient Risk Management

Directory of Open Access Journals (Sweden)

Sang-Yong Joo

1999-03-01

Full Text Available This thesis analyzes the relationship between the exchange rate of Korean Won and US dollar and the amount of foreign exchange, and studies the direction of the amendment of the risk control of foreign exchange. The GARCH (Generalized Auto Regressive Conditional Heteroscedasticity model which visually embodies the auto-regress of the wave of exchange rate shows that the amount of trade will enhance the fluidity of the exchange rate, that is, the various expects of the participators of the market affect the amount of trade and the fluidity, so in the process of trading, the trader who is in the dry tree of information bears more trading expenditure. It is predicted that the liberalization of foreign exchange rate and fluctuated exchange rate system will jointly bring the enhancement of the fluidity of the exchange rate and the amount of exchange trade. The change of this system will bring the rise of participators in foreign exchange market; meanwhile, it will also initiate superfluous fluidity of foreign exchange market. In order to overcome this problem, the government needs to implement the development strategy of the understructure of the foreign exchange market and the enterprises need to carry through systemic exchange rate risk control.

Symmetry in social exchange and health

Science.gov (United States)

Siegrist, Johannes

2005-10-01

Symmetry is a relevant concept in sociological theories of exchange. It is rooted in the evolutionary old norm of social reciprocity and is particularly important in social contracts. Symmetry breaking through violation of the norm of reciprocity generates strain in micro-social systems and, above all, in victims of non-symmetric exchange. In this contribution, adverse healthconsequences of symmetry breaking in contractual social exchange are analysed, with a main focus on the employment contract. Scientific evidence is derived from prospective epidemiological studies testing the model of effort-reward imbalance at work. Overall, a twofold elevated risk of incident disease is observed in employed men and women who are exposed to non-symmetric exchange. Health risks include coronary heart disease, depression and alcohol dependence, among others. Preliminary results suggest similar effects on health produced by symmetry breaking in other types of social relationships (e.g. partnership, parental roles). These findings underline the importance of symmetry in contractual social exchange for health and well-being.

Measuring the costs of exchange rate volatility

OpenAIRE

Paul R. Bergin

2004-01-01

Many countries go to great lengths to manage their exchange rates. Probably the most prominent recent example is the European Monetary Union, where all the members abandoned their national currencies and adopted the euro. A number of developing countries maintain other kinds of regimes of managed exchange rates, even though they face potent market pressures to let their exchange rates float. One of the main motives for these arrangements stems from the extreme volatility of exchange rates. Th...

Rethinking exchange market models as optimization algorithms

Science.gov (United States)

Luquini, Evandro; Omar, Nizam

2018-02-01

The exchange market model has mainly been used to study the inequality problem. Although the human society inequality problem is very important, the exchange market models dynamics until stationary state and its capability of ranking individuals is interesting in itself. This study considers the hypothesis that the exchange market model could be understood as an optimization procedure. We present herein the implications for algorithmic optimization and also the possibility of a new family of exchange market models

Physician capability to electronically exchange clinical information, 2011.

Science.gov (United States)

Patel, Vaishali; Swain, Matthew J; King, Jennifer; Furukawa, Michael F

2013-10-01

To provide national estimates of physician capability to electronically share clinical information with other providers and to describe variation in exchange capability across states and electronic health record (EHR) vendors using the 2011 National Ambulatory Medical Care Survey Electronic Medical Record Supplement. Survey of a nationally representative sample of nonfederal office-based physicians who provide direct patient care. The survey was administered by mail with telephone follow-up and had a 61% weighted response rate. The overall sample consisted of 4326 respondents. We calculated estimates of electronic exchange capability at the national and state levels, and applied multivariate analyses to examine the association between the capability to exchange different types of clinical information and physician and practice characteristics. In 2011, 55% of physicians had computerized capability to send prescriptions electronically; 67% had the capability to view lab results electronically; 42% were able to incorporate lab results into their EHR; 35% were able to send lab orders electronically; and, 31% exchanged patient clinical summaries with other providers. The strongest predictor of exchange capability is adoption of an EHR. However, substantial variation exists across geography and EHR vendors in exchange capability, especially electronic exchange of clinical summaries. In 2011, a majority of office-based physicians could exchange lab and medication data, and approximately one-third could exchange clinical summaries with patients or other providers. EHRs serve as a key mechanism by which physicians can exchange clinical data, though physicians' capability to exchange varies by vendor and by state.

Classifying 50 years of Bell inequalities

International Nuclear Information System (INIS)

Rosset, Denis; Gisin, Nicolas; Bancal, Jean-Daniel

2014-01-01

Since John S Bell demonstrated the interest of studying linear combinations of probabilities in relation with the EPR paradox in 1964, Bell inequalities have lead to numerous developments. Unfortunately, the description of Bell inequalities is subject to several degeneracies, which make any exchange of information about them unnecessarily hard. Here, we analyze these degeneracies and propose a decomposition for Bell-like inequalities based on a set of reference expressions which is not affected by them. These reference expressions set a common ground for comparing Bell inequalities. We provide algorithms based on finite group theory to compute this decomposition. Implementing these algorithms allows us to set up a compendium of reference Bell-like inequalities, available online at www.faacets.com. This website constitutes a platform where registered Bell-like inequalities can be explored, new inequalities can be compared to previously-known ones and relevant information on Bell inequalities can be added in a collaborative manner. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell’s theorem’. (paper)

Classifying 50 years of Bell inequalities

Science.gov (United States)

Rosset, Denis; Bancal, Jean-Daniel; Gisin, Nicolas

2014-10-01

Since John S Bell demonstrated the interest of studying linear combinations of probabilities in relation with the EPR paradox in 1964, Bell inequalities have lead to numerous developments. Unfortunately, the description of Bell inequalities is subject to several degeneracies, which make any exchange of information about them unnecessarily hard. Here, we analyze these degeneracies and propose a decomposition for Bell-like inequalities based on a set of reference expressions which is not affected by them. These reference expressions set a common ground for comparing Bell inequalities. We provide algorithms based on finite group theory to compute this decomposition. Implementing these algorithms allows us to set up a compendium of reference Bell-like inequalities, available online at www.faacets.com. This website constitutes a platform where registered Bell-like inequalities can be explored, new inequalities can be compared to previously-known ones and relevant information on Bell inequalities can be added in a collaborative manner. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell’s theorem’.

Refractive outcomes after multifocal intraocular lens exchange.

Science.gov (United States)

Kim, Eric J; Sajjad, Ahmar; Montes de Oca, Ildamaris; Koch, Douglas D; Wang, Li; Weikert, Mitchell P; Al-Mohtaseb, Zaina N

2017-06-01

To evaluate the refractive outcomes after multifocal intraocular lens (IOL) exchange. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Retrospective case series. Patients had multifocal IOL explantation followed by IOL implantation. Outcome measures included type of IOL, surgical indication, corrected distance visual acuity (CDVA), and refractive prediction error. The study comprised 29 patients (35 eyes). The types of IOLs implanted after multifocal IOL explantation included in-the-bag IOLs (74%), iris-sutured IOLs (6%), sulcus-fixated IOLs with optic capture (9%), sulcus-fixated IOLs without optic capture (9%), and anterior chamber IOLs (3%). The surgical indication for exchange included blurred vision (60%), photic phenomena (57%), photophobia (9%), loss of contrast sensitivity (3%), and multiple complaints (29%). The CDVA was 20/40 or better in 94% of eyes before the exchange and 100% of eyes after the exchange (P = .12). The mean refractive prediction error significantly decreased from 0.22 ± 0.81 diopter (D) before the exchange to -0.09 ± 0.53 D after the exchange (P exchange to 0.23 D after the exchange (P exchange can be performed safely with good visual outcomes using different types of IOLs. A lower refractive prediction error and a higher likelihood of 20/40 or better vision can be achieved with the implantation of the second IOL compared with the original multifocal IOL, regardless of the final IOL position. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Evaluating the Uncertainty in Exchange Parameters Determined from Off-Resonance R1ρ Relaxation Dispersion for Systems in Fast Exchange

Science.gov (United States)

Bothe, Jameson R.; Stein, Zachary W.; Al-Hashimi, Hashim M.

2014-01-01

Spin relaxation in the rotating frame (R1ρ) is a powerful NMR technique for characterizing fast microsecond timescale exchange processes directed toward short-lived excited states in biomolecules. At the limit of fast exchange, only kex = k1 + k−1 and Φıx = pGpE(Δω)2 can be determined from R1ρ data limiting the ability to characterize the structure and energetics of the excited state conformation. Here, we use simulations to examine the uncertainty with which exchange parameters can be determined for two state systems in intermediate-to-fast exchange using off-resonance R1ρ relaxation dispersion. R1ρ data computed by solving the Bloch-McConnell equations reveals small but significant asymmetry with respect to offset (R1ρ(ΔΩ) ≠ R1ρ(−ΔΩ)), which is a hallmark of slow-to-intermediate exchange, even under conditions of fast exchange for free precession chemical exchange line broadening (kex/Δω > 10). A grid search analysis combined with bootstrap and Monte-Carlo based statistical approaches for estimating uncertainty in exchange parameters reveals that both the sign and magnitude of Δω can be determined at a useful level of uncertainty for systems in fast exchange (kex/Δω exchange parameters. Results from simulations are complemented by analysis of experimental R1ρ data measured in three nucleic acid systems with exchange processes occurring on the slow (kex/Δω = 0.2; pE = ~ 0.7%), fast (kex/Δω = ~10–16; pE = ~13%) and very fast (kex = 39,000 s−1) chemical shift timescales. PMID:24819426

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Science.gov (United States)

2010-04-01

... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240...

Social exchange : Relations and networks

NARCIS (Netherlands)

Dijkstra, Jacob

2015-01-01

In this short paper, I review the literature on social exchange networks, with specific attention to theoretical and experimental research. I indicate how social exchange theory is rooted in general social theory and mention a few of its main links to social network analysis and empirical network

Ion exchange in the nuclear power industry

International Nuclear Information System (INIS)

Lehto, J.

1993-01-01

Ion exchangers are used in many fields in the nuclear power industry. At nuclear power plants, organic ion exchange resins are mainly used for the removal of ionic and particulate contaminants from the primary circuit, condensate and fuel storage pond waters. Ion exchange resins are used for the solidification of low- and medium-active nuclear waste solutions. The number of applications of zeolites, and other inorganic ion exchangers, in the separation of radionuclides from nuclear waste solutions has been increasing since the 1980s. In nuclear fuel reprocessing plants, ion exchange is used for the solidification of low- and medium-active waste solutions, as well as for the partitioning of radioactive elements for further use. (Author)

Composite inorganic ion-exchangers and their applications

International Nuclear Information System (INIS)

Sebesta, F.; John, J.; Motl, A.

1998-01-01

Composite inorganic ion exchangers are described containing modified polyacrylonitrile as the binding polymer. An overview of existing composite ion exchangers is presented, and the universality and assets of the developed procedure of treatment of inorganic ion exchanger powders are highlighted. Examples of applicability of the ion exchangers to the separation and concentration of radionuclides include in particular: wastes from the operation of nuclear power plants, contaminated surface waters and ground water, high level radioactive wastes from spent fuel reprocessing, and wastewaters from uranium ore mining and milling. In addition, composite ion exchangers find use in the monitoring of contamination of the hydrosphere and the environment and in the investigation of radionuclide migration in surface waters and ground water

Estimating Foreign Exchange Reserve Adequacy

Directory of Open Access Journals (Sweden)

Abdul Hakim

2013-04-01

Full Text Available Accumulating foreign exchange reserves, despite their cost and their impacts on other macroeconomics variables, provides some benefits. This paper models such foreign exchange reserves. To measure the adequacy of foreign exchange reserves for import, it uses total reserves-to-import ratio (TRM. The chosen independent variables are gross domestic product growth, exchange rates, opportunity cost, and a dummy variable separating the pre and post 1997 Asian financial crisis. To estimate the risky TRM value, this paper uses conditional Value-at-Risk (VaR, with the help of Glosten-Jagannathan-Runkle (GJR model to estimate the conditional volatility. The results suggest that all independent variables significantly influence TRM. They also suggest that the short and long run volatilities are evident, with the additional evidence of asymmetric effects of negative and positive past shocks. The VaR, which are calculated assuming both normal and t distributions, provide similar results, namely violations in 2005 and 2008.

[Comparison of the effects of exchange forms on social solidarity].

Science.gov (United States)

Inaba, Misato; Takahashi, Nobuyuki

2012-04-01

Although social solidarity is an essential component that helps maintaining social order, what produces solidarity and how does it work have not been fully investigated. We conducted an experiment to examine whether experiencing different forms of social exchange produces different levels of solidarity. We compared four forms of social exchange: reciprocal exchange (exchange resources without negotiation), negotiated exchange (with negotiation), pure-generalized exchange (giver can choose who to give) and chain-generalized exchange (giver cannot choose who to give). Two dimensions classify these exchanges: the number of players (two vs. more than two), and involvement of negotiation. Reciprocal and negotiated exchanges occur within dyads, while pure- and chain-generalized exchanges involve three or more players. Only the negotiated exchange involves negotiation process; the other exchanges are purely unilateral giving. Participants played a one-shot social dilemma game (SDG) before and after social exchange session. The more the players cooperated in SDG, the stronger the social solidarity. Results show that the cooperation rate in SDG increased more in the reciprocal, pure- and chain-generalized exchange conditions than that in the negotiated exchange condition, suggesting that social solidarity is facilitated by experiencing social exchange which does not involve negotiation.

Educators Exchange: A Program Evaluation.

Science.gov (United States)

Armstrong, William B.

The Educators Exchange Program (EEP) was established under a training and educational exchange agreement reached by California's San Diego Community College District (SDCCD) and the republic of Mexico. In the program, the District provided a 4-week technological training program to faculty at Centros de Capacitacion Tecnologica Industrial…

Auxiliary Heat Exchanger Flow Distribution Test

International Nuclear Information System (INIS)

Kaufman, J.S.; Bressler, M.M.

1983-01-01

The Auxiliary Heat Exchanger Flow Distribution Test was the first part of a test program to develop a water-cooled (tube-side), compact heat exchanger for removing heat from the circulating gas in a high-temperature gas-cooled reactor (HTGR). Measurements of velocity and pressure were made with various shell side inlet and outlet configurations. A flow configuration was developed which provides acceptable velocity distribution throughout the heat exchanger without adding excessive pressure drop

Ion exchange and hydrolysis reactions in zeolites

International Nuclear Information System (INIS)

Harjula, Risto.

1993-09-01

Among other uses, zeolites are efficient cation exchangers for aquatic pollution control. At present they they are mainly used in nuclear waste effluent treatment and in detergency. In the thesis, several ion exchange equilibria, important in these main fields of zeolite applications, were studied, with special emphasis on the formulation and calculation of the equilibria. The main interest was the development of thermodynamic formulations for the calculation of zeolite ion exchange equilibria in solutions of low or very low (trace) ion concentration, which are relevant for the removal of trace pollutants, such as radionuclides, from waste waters. Two groups of zeolite-cation systems were studied. First, binary Ca 2+ /Na + exchange in zeolites X and Y, which are of interest for detergency applications. Second, binary Cs + /Na + and Cs + /K + exchanges, and ternary Cs + /Na + /K + exchange in mordenite, which are important in nuclear waste effluent treatment. The thesis is based on five previous publications by author. (100 refs., 7 figs.)

Inflation Targeting and Exchange Rate Management in Korea

Directory of Open Access Journals (Sweden)

Won-Am Park

2008-06-01

Full Text Available This paper investigates the experience of inflation targeting in Korea with an emphasis on exchange rate management. The Korean call rate responded to not only expected inflation, but also to output gap and changes in the real effective exchange rate of the Korean won, when we estimated the call rate reaction function over the period of 1999-2007. It was found that the call rate responded to changes in real effective exchange rate more than it did to expected inflation. We also examined whether Korean inflation targeting was actually centered on the exchange rate by estimating the Singaporean style of exchange rate reaction function. It was found that Korean monetary policy was not exchange-rate- centered, since the nominal effective exchange rate of the Korean won responded modestly to inflation and output gap, far less than did the Singaporean dollar.

36 CFR 254.4 - Agreement to initiate an exchange.

Science.gov (United States)

2010-07-01

... exchange. 254.4 Section 254.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS Land Exchanges § 254.4 Agreement to initiate an exchange. (a) Exchanges may be proposed by the Forest Service or by any person, State, or local government. Initial exchange proposals...

Definition-consistent measurement of exchange market pressure

NARCIS (Netherlands)

Klaassen, F.; Jager, H.

2011-01-01

Currencies can be under severe pressure, but in a managed exchange rate regime that is not fully visible via the change in the exchange rate. The literature has proposed a way to measure such exchange market pressure (EMP) indirectly, by adding interest rate changes and forex interventions to the

Heat exchanger

International Nuclear Information System (INIS)

Bennett, J.C.

1975-01-01

A heat exchanger such as forms, for example, part of a power steam boiler is made up of a number of tubes that may be arranged in many different ways, and it is necessary that the tubes be properly supported. The means by which the tubes are secured must be as simple as possible so as to facilitate construction and must be able to continue to function effectively under the varying operating conditions to which the heat exchanger is subject. The arrangement described is designed to meet these requirements, in an improved way. The tubes are secured to a member extending past several tubes and abutment means are provided. At least some of the abutment means comprise two abutment pieces and a wedge secured to the supporting member, that acts on these pieces to maintain the engagement. (U.K.)

On equilibrium real exchange rates in euro area: Special focus on behavioral equilibrium exchange rates in Ireland and Greece

Directory of Open Access Journals (Sweden)

Klára Plecitá

2012-01-01

Full Text Available This paper focuses on the intra-euro-area imbalances. Therefore the first aim of this paper is to identify euro-area countries exhibiting macroeconomic imbalances. The subsequent aim is to estimate equilibrium real exchange rates for these countries and to compute their degrees of real exchange rate misalignment. The intra-area balance is assessed using the Cluster Analysis and the Principle Component Analysis; on this basis Greece and Ireland are selected as the two euro-area countries with largest imbalances in 2010. Further the medium-run equilibrium exchange rates for Greece and Ireland are estimated applying the Behavioral Equilibrium Exchange Rate (BEER approach popularised by Clark and MacDonald (1998. In addition, the long-run equilibrium exchange rates are estimated using the Permanent Equilibrium Exchange Rate (PEER model. Employing the BEER and PEER approaches on quarterly time series of real effective exchange rates (REER from 1997: Q1 to 2010: Q4 we identify an undervaluation of the Greek and Irish REER around their entrance to the euro area. For the rest of the period analysed their REER is broadly in line with estimated BEER and PEER levels.

Search for a new exchange-rate regime.

Science.gov (United States)

Williamson, J

1987-07-31

The regime of unmanaged floating exchange rates was implicitly judged a failure when, with the Plaza Agreement, attempts at cooperative exchange-rate management were reintroduced primarily because of concern at the size of misalignments. Any satisfactory successor regime will need to limit misalignments while retaining the genuine social benefits of exchange-rate flexibility. It is argued that a system of target zones for exchange rates, ideally embedded in a more comprehensive set of guidelines for international economic policy coordination, could best reconcile these needs.

Ion exchange process: History, evolution and applications

International Nuclear Information System (INIS)

Mazzoldi, P.; Carturan, S.; Sada, C.; Quaranta, A.; Sglavo, V.M.

2013-01-01

The aim of this paper is to present a review on some aspects and applications of ion exchange process in glasses, ferroelectric and polymers in the fields of optics, nanotechnology, gas sensors and chemical strengthening. The formation of nanoparticles in ion-exchanged glasses, as effect of ion or laser irradiation, is discussed. A discussion on the potentialities of ion exchange process in comparison to ion implantation in optical devices and nanotechnology is also introduced. Analytical techniques applied to the study of the ion exchange process are illustrated. The studies of ion exchange process in “Natural materials” constitute the content of a specific paragraph, for applications in water cleaning. Some initial considerations on the “old age” of this technique are introduced.

Tritium isotopic exchange in air detritiation dryers

International Nuclear Information System (INIS)

Everatt, A.E.; Johnson, R.E.; Senohrabek, J.A.; Shultz, C.M.

1989-02-01

Isotopic exchange between tritiated and non-tritiated water species in a molecular sieve bed has been demonstrated. At high humidities (+6 degrees Celsius dew point) the rate of tritium isotopic exchange in a 2.4 L molecular sieve bed has been demonstrated to be at least 50% of published exchange rates. In an industrial-sized air detritiation dryer, utilizing the pretreatment technique of H 2 O steam washing to elute the residual tritium, a DF of 12 600 has been demonstrated when operating at an inlet vapor tritium concentration of 14 Ci/kg and at inlet and outlet dew points of 4.8 and -54 degrees Celsius, respectively. In the NPD dryer bed studied, which was not optimally designed for full benefit from isotopic exchange, at least one order of magnitude in additional detritiation is attributed to isotopic exchange in the unsaturated zone. The technique of eluting the residual tritium from an industrial sized bed by H 2 O washing at high temperature, high humidity and low bed loading has been demonstrated to be a fast and effective way of removing tritium from a molecular sieve bed during regeneration. The isotopic exchange model accurately predicted the exchange between tritiated and non-tritiated water species in a molecular sieve bed where there is no net adsorption or desorption. The model's prediction of the tritium breakthrough trend observed in the NPD tests was poor; however, a forced fit can be achieved if the exchange rates in the MTZ and the unsaturated zone are manipulated. More experiments are needed to determine the relative rates of tritium exchange in the saturated, mass transfer, and unsaturated zones of a dryer bed

Tube in shell heat exchangers

International Nuclear Information System (INIS)

Hayden, O.; Willby, C.R.; Sheward, G.E.; Ormrod, D.T.; Firth, G.F.

1980-01-01

An improved tube-in-shell heat exchanger to be used between liquid metal and water is described for use in the liquid metal coolant system of fast breeder reactors. It is stated that this design is less prone to failures which could result in sodium water reactions than previous exchangers. (UK)

Design of common heat exchanger network for batch processes

International Nuclear Information System (INIS)

Anastasovski, Aleksandar

2014-01-01

Heat integration of energy streams is very important for the efficient energy recovery in production systems. Pinch technology is a very useful tool for heat integration and maximizing energy efficiency. Creating of heat exchangers network as a common solution for systems in batch mode that will be applicable in all existing time slices is very difficult. This paper suggests a new methodology for design of common heat exchanger network for batch processes. Heat exchanger network designs were created for all determined repeatable and non-repeatable time periods – time slices. They are the basis for creating the common heat exchanger network. The common heat exchanger network as solution, satisfies all heat-transfer needs for each time period and for every existing combination of selected streams in the production process. This methodology use split of some heat exchangers into two or more heat exchange units or heat exchange zones. The reason for that is the multipurpose use of heat exchangers between different pairs of streams in different time periods. Splitting of large heat exchangers would maximize the total heat transfer usage of heat exchange units. Final solution contains heat exchangers with the minimum heat load as well as the minimum need of heat transfer area. The solution is applicable for all determined time periods and all existing stream combinations. - Highlights: •Methodology for design of energy efficient systems in batch processes. •Common Heat Exchanger Network solution based on designs with Pinch technology. •Multipurpose use of heat exchangers in batch processes

The Exchange Value Embedded in a Transport System

International Nuclear Information System (INIS)

Xia Qinglan; Xu Shaofeng

2010-01-01

This paper shows that a well designed transport system has an embedded exchange value by serving as a market for potential exchange between consumers. Under suitable conditions, one can improve the welfare of consumers in the system simply by allowing some exchange of goods between consumers during transportation without incurring additional transportation cost. We propose an explicit valuation formula to measure this exchange value for a given compatible transport system. This value is always nonnegative and bounded from above. Criteria based on transport structures, preferences and prices are provided to determine the existence of a positive exchange value. Finally, we study a new optimal transport problem with an objective taking into account of both transportation cost and exchange value.

Characteristics of resin floc dispersion of anion and cation exchange resin in precoat filter using powdered ion exchange resin

Energy Technology Data Exchange (ETDEWEB)

Adachi, Tetsurou (Nitto Denko Corp., Ibaraki, Osaka (Japan)); Sawa, Toshio; Shindoh, Toshikazu

1989-09-01

The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of resin floc dispersion. The factors related to resin floc dispersion of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index in addition to the measurement of physical, chemical and electrochemical properties of powdered ion exchange resin. The effect of adsorption of iron oxide and polymer electrolyte and of ion exchange were determined. In addition, considered floc dispersion with adsorbing iron oxide, it was assumed that the amount and filling ratio of resin floc were related to summation and multiplication of surface electric charge respectively. An experimental expression was obtained for simulation of the change of specific settle volume of resin floc by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author).

Characteristics of resin floc dispersion of anion and cation exchange resin in precoat filter using powdered ion exchange resin

International Nuclear Information System (INIS)

Adachi, Tetsurou; Sawa, Toshio; Shindoh, Toshikazu.

1989-01-01

The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of resin floc dispersion. The factors related to resin floc dispersion of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index in addition to the measurement of physical, chemical and electrochemical properties of powdered ion exchange resin. The effect of adsorption of iron oxide and polymer electrolyte and of ion exchange were determined. In addition, considered floc dispersion with adsorbing iron oxide, it was assumed that the amount and filling ratio of resin floc were related to summation and multiplication of surface electric charge respectively. An experimental expression was obtained for simulation of the change of specific settle volume of resin floc by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author)

Rapid deuterium exchange-in time for probing conformational change

International Nuclear Information System (INIS)

Dharmasiri, K.; Smith, D.L.

1995-01-01

Isotopic exchange of protein backbone amide hydrogens has been used extensively as a sensitive probe of protein structure. One of the salient features of hydrogen exchange is the vast range of exchange rates in one protein. Isotopic exchange methods have been used to study the structural features including protein folding and unfolding (1), functionally different forms of proteins (2), protein-protein complexation (3), and protein stability parameter. Many backbone amide protons that are surface accessible and are not involved in hydrogen bonding undergo rapid deuterium exchange. In order to study, fast exchanging amide protons, fast exchange-in times are necessary

Advantages of chemical exchange-sensitive spin-lock (CESL) over chemical exchange saturation transfer (CEST) for hydroxyl- and amine-water proton exchange studies.

Science.gov (United States)

Jin, Tao; Kim, Seong-Gi

2014-11-01

The chemical exchange (CE) rate of endogenous hydroxyl and amine protons with water is often comparable to the difference in their chemical shifts. These intermediate exchange processes have been imaged by the CE saturation transfer (CEST) approach with low-power and long-duration irradiation. However, the sensitivity is not optimal and, more importantly, the signal is contaminated by slow magnetization transfer processes. Here, the properties of CEST signals are compared with those of a CE-sensitive spin-lock (CESL) technique irradiating at the labile proton frequency. First, using a higher power and shorter irradiation in CE-MRI, we obtain: (i) an increased selectivity to faster CE rates via a higher sensitivity to faster CEs and a lower sensitivity to slower CEs and magnetization transfer processes; and (ii) a decreased in vivo asymmetric magnetization transfer contrast measured at ±15 ppm. The sensitivity gain of CESL over CEST is higher for a higher power and shorter irradiation. Unlike CESL, CEST signals oscillate at a very high power and short irradiation. Second, time-dependent CEST and CESL signals are well modeled by analytical solutions of CE-MRI with an asymmetric population approximation, which can be used for quantitative CE-MRI and validated by simulations of Bloch-McConnell equations and phantom experiments. Finally, the in vivo amine-water proton exchange contrast measured at 2.5 ppm with ω1 = 500 Hz is 18% higher in sensitivity for CESL than CEST at 9.4 T. Overall, CESL provides better exchange rate selectivity and sensitivity than CEST; therefore, CESL is more suitable for CE-MRI of intermediate exchange protons. Copyright © 2014 John Wiley & Sons, Ltd.

22 CFR Appendix B to Part 62 - Exchange Visitor Program Services, Exchange-Visitor Program Application

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Exchange Visitor Program Services, Exchange-Visitor Program Application B Appendix B to Part 62 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY... Media and Communications; 03—Education; 04—Business and Commercial; 05—Banking and Financial; 06...

Role of Exchange Rate Volatility in Exchange Rate Pass-Through to Import Prices: Some Evidence from Japan

OpenAIRE

Guneratne Banda Wickremasinghe; Param Silvapulle

2004-01-01

This paper investigates the effect of exchange rate volatility on the degree of exchange rate pass-through in Japan for the period January 1975 to June 1997. Although several studies put forward theoretical arguments for the volatility-domestic import price relationship, only a very few studies produced empirical evidence. The volatility of contractual currency based exchange rate index returns was modelled using GARCH-type processes with skewed student t-distribution, capturing the typical n...

Trust and Transitions in Modes of Exchange

Science.gov (United States)

Cheshire, Coye; Gerbasi, Alexandra; Cook, Karen S.

2010-01-01

In this study, we investigate the relationship between uncertainty and trust in exogenous shifts in modes of social exchange (i.e., those that are not initiated by the individuals in a given exchange system). We explore how transitions from a high uncertainty environment (reciprocal exchange) to lower-uncertainty environments (nonbinding or…

Exchange rates of creatine kinase metabolites: feasibility of imaging creatine by chemical exchange saturation transfer MRI.

Science.gov (United States)

Haris, Mohammad; Nanga, Ravi Prakash Reddy; Singh, Anup; Cai, Kejia; Kogan, Feliks; Hariharan, Hari; Reddy, Ravinder

2012-11-01

Creatine (Cr), phosphocreatine (PCr) and adenosine-5-triphosphate (ATP) are major metabolites of the enzyme creatine kinase (CK). The exchange rate of amine protons of CK metabolites at physiological conditions has been limited. In the current study, the exchange rate and logarithmic dissociation constant (pKa) of amine protons of CK metabolites were calculated. Further, the chemical exchange saturation transfer effect (CEST) of amine protons of CK metabolites with bulk water was explored. At physiological temperature and pH, the exchange rate of amine protons in Cr was found to be 7-8 times higher than PCr and ATP. A higher exchange rate in Cr was associated with lower pKa value, suggesting faster dissociation of its amine protons compared to PCr and ATP. CEST MR imaging of these metabolites in vitro in phantoms displayed predominant CEST contrast from Cr and negligible contribution from PCr and ATP with the saturation pulse parameters used in the current study. These results provide a new method to perform high-resolution proton imaging of Cr without contamination from PCr. Potential applications of these finding are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Exchange-Mediated Contrast in CEST and Spin-Lock Imaging

Science.gov (United States)

Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F.; Gore, John C.

2014-01-01

PURPOSE Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. METHODS Simulations and experimental measurements at 9.4T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. RESULTS The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. > 2ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate to fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CONCLUSION CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ dependent acquisitions can be employed to selectively portray protons of specific exchange rates. PMID:24239335

Exchange-mediated contrast in CEST and spin-lock imaging.

Science.gov (United States)

Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F; Gore, John C

2014-01-01

Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. Simulations and experimental measurements at 9.4 T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. >2 ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate-to-fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ-dependent acquisitions can be employed to selectively portray protons of specific exchange rates. © 2013.

EFECT OF FOREIGN EXCHANGE RATE FLUCTUATIONS ON NIGERIAN ECONOMY

Directory of Open Access Journals (Sweden)

Lawrence Olisaemeka UFOEZE

2018-03-01

Full Text Available This study investigated the effect of exchange rate fluctuations on Nigerian economy. The fixed and floating exchange eras were compared to know the exchange rate system in which the economy has fairly better. The time period covered was 1970 to 2012. The study employed the ordinary least square (OLS multiple regression technique for the analysis. The coefficient of determination (R2, F-test, t-test, beta and Durbin-Watson were used in the interpretation of the results. The resulted revealed that about 85% of the changes in macroeconomic indicators are explained in the fixed exchange era. In the floating exchange era, 99% was explained while the whole periods has 73% explanatory power, hence the floating exchange era (1986 to date is more effective in explaining economic trend in Nigeria. Also, exchange rate has significant positive effect on GDP during the fixed exchange rate era and negative effect the eras floating and all-time; inflation has insignificant negative effect on GDP during the fixed exchange era; significant effect in floating era and significant negative effect in the all-time period; money supply has insignificant negative effect GDP in fixed exchange era; and significant positive effect during the floating and all-time period; and oil revenue has significant positive effect on the GDP in all the exchange rate regimes (floating, fixed and all-time in Nigeria.  The study thus conclude that exchange rate movement is a good indicator for monitoring Nigerian economic growth. So far exchange rate has always been a key economic indicator for Nigeria. The floating exchange period has outperformed the fixed exchange rate in terms of contribution inflation, money supply and oil revenue to economic growth. This indicate that the floating exchange rate has been a better economic regime for sustainable economic growth in Nigeria. From the findings, it is evident that oil revenue has positive effect in Nigeria and has remained the mainstay

Exchange Options

NARCIS (Netherlands)

Jamshidian, F.

2007-01-01

The contract is described and market examples given. Essential theoretical developments are introduced and cited chronologically. The principles and techniques of hedging and unique pricing are illustrated for the two simplest nontrivial examples: the classical Black-Scholes/Merton/Margrabe exchange

Exchange rates.

Science.gov (United States)

Mills, Bev

2003-09-01

IN MAY this year, I was lucky enough to go to Larissa in northern Greece as part of Hope Exchange 2003, an annual study tour organised by the European Union's hospital committee and administered by the Institute of Healthcare Management (IHM).

Ion exchange : principles and applications

International Nuclear Information System (INIS)

Bank, Nader; Majumdar, A.S.

1975-01-01

An attempt is made to provide a brief state-of-the-art review of the basic principles underlying the unit operation of ion exchange and its numerous and diverse commercial applications. A selective bibliography is provided for the benefit of the reader interested in pursuing any specific aspect of ion exchange. (author)

On exact and approximate exchange-energy densities

DEFF Research Database (Denmark)

Springborg, Michael; Dahl, Jens Peder

1999-01-01

Based on correspondence rules between quantum-mechanical operators and classical functions in phase space we construct exchange-energy densities in position space. Whereas these are not unique but depend on the chosen correspondence rule, the exchange potential is unique. We calculate this exchange......-energy density for 15 closed-shell atoms, and compare it with kinetic- and Coulomb-energy densities. It is found that it has a dominating local-density character, but electron-shell effects are recognizable. The approximate exchange-energy functionals that have been proposed so far are found to account only...

Ion-exchanger ultraviolet spectrophotometry for uranium(VI)

International Nuclear Information System (INIS)

Waki, H.; Korkisch, J.

1983-01-01

A sensitive method based on solid-phase spectrophotometry has been developed for the microdetermination of uranium(VI) in water samples. Uranium is sorbed on the anion-exchanger QAE-Sephadex from thiocyanate solution and the absorbance of the exchanger is measured at 300 nm. This method is about 30 times more sensitive than solution spectrophotometry. Absorption spectra of various metals in the anion-exchanger phase are presented and their interferences discussed. A procedure for the cation-exchange separation of uranium from accompanying elements before spectral measurement of uranium is proposed. (author)

Floating Exchange Rate Regime

OpenAIRE

Quader, Syed Manzur

2004-01-01

In recent years, many developing countries having a history of high inflation, unfavorable balance of payment situation and a high level of foreign currencies denominated debt, have switched or are in the process of switching to a more flexible exchange rate regime. Therefore, the stability of the exchange rate and the dynamics of its volatility are more crucial than before to prevent financial crises and macroeconomic disturbances. This paper is designed to find out the reasons behind Bangla...

Sorption by cation exchange

International Nuclear Information System (INIS)

Bradbury, M.H.; Baeyens, B.

1994-04-01

A procedure for introducing exchange into geochemical/surface complexation codes is described. Beginning with selectivity coefficients, K c , defined in terms of equivalent fractional ion occupancies, a general expression for the molar based exchange code input parameters, K ex , is derived. In natural systems the uptake of nuclides onto complex sorbents often occurs by more than one mechanism. The incorporation of cation exchange and surface complexation into a geochemical code therefore enables sorption by both mechanisms to be calculated simultaneously. The code and model concepts are tested against sets of experimental data from widely different sorption studies. A proposal is made to set up a data base of selectivity coefficients. Such a data base would form part of a more general one consisting of sorption mechanism specific parameters to be used in conjunction with geochemical/sorption codes to model and predict sorption. (author) 6 figs., 6 tabs., 26 refs

Searching for an Appropriate Exchange Rate Regime

Directory of Open Access Journals (Sweden)

Yunjong Wang

2001-06-01

Full Text Available This paper attempts to survey current debates on the choice of exchange rate regime in emerging market economies. The issue of choosing an appropriate exchange rate regime is being actively discussed since the recent Asian crisis. As a lesson from the recent crises, one widely shared conclusion is that soft peg exchange rate regimes are extremely vulnerable in a world of volatile capital movements. Consequently, new orthodoxy based on the impossible trinity hypothesis favours two corner solutions ― greater flexibility or credible institutional assurance, like a currency board system or dollarization. Nevertheless, questions whether such corner solutions are adequate for developing countries are rising of late. "Fear of floating" is still conspicuous in many developing countries having adopted nominally a free-floating exchange rate regime. Developing countries are sensitive to exchange rate fluctuations because the cost of exchange rate volatility is greater than the benefit when compared to developed countries. Monitoring bands is a compromise solution, but it still needs further enhancement of estimation techniques for fundamental equilibrium exchange rates in order to make those estimation results more workable in practice. Other alternatives include the creation of soft peg of the G-3 currencies. Despite counterarguments, the stability of G-3 currencies could prove to be beneficial to emerging market economies.

Heat exchanger, head and shell acceptance criteria

International Nuclear Information System (INIS)

Lam, P.S.; Sindelar, R.L.

1992-09-01

Instability of postulated flaws in the head component of the heat exchanger could not produce a large break, equivalent to a DEGB in the PWS piping, due to the configuration of the head and restraint provided by the staybolts. Rather, leakage from throughwall flaws in the head would increase with flaw length with finite leakage areas that are bounded by a post-instability flaw configuration. Postulated flaws at instability in the shell of the heat exchanger or in the cooling water nozzles could produce a large break in the Cooling Water System (CWS) pressure boundary. An initial analysis of flaw stability for postulated flaws in the heat exchanger head was performed in January 1992. This present report updates that analysis and, additionally, provides acceptable flaw configurations to maintain defined structural or safety margins against flaw instability of the external pressure boundary components of the heat exchanger, namely the head, shell, and cooling water nozzles. Structural and flaw stability analyses of the heat exchanger tubes, the internal pressure boundary of the heat exchangers or interface boundary between the PWS and CWS, were previously completed in February 1992 as part of the heat exchanger restart evaluation and are not covered in this report

31 CFR 352.7 - Issues on exchange.

Science.gov (United States)

2010-07-01

... exchange with his or her own funds, or received them as a gift, inheritance or legacy, or as a result of... received them jointly as a gift, inheritance, or legacy or as a result of judicial proceedings, both... payment stamp on the securities and the exchange application. (g) Tax-deferred exchanges. (1) Continuation...

Where Would the EUR/CHF Exchange Rate be Without the SNB's Minimum Exchange Rate Policy?

DEFF Research Database (Denmark)

Hanke, Michael; Poulsen, Rolf; Weissensteiner, Alex

2015-01-01

Since its announcement made on September 6, 2011, the Swiss National Bank (SNB) has been pursuing the goal of a minimum EUR/CHF exchange rate of 1.20, promising to intervene on currency markets to prevent the exchange rate from falling below this level.We use a compound option pricing approach...

Management of exchange rate regimes in emerging Asia

Directory of Open Access Journals (Sweden)

Ramkishen S. Rajan

2012-04-01

Full Text Available This paper revisits the issue of exchange rate regimes in emerging Asia over the decade 1999–2009. It finds that while Asia is home to a wide array of exchange rate regimes, there are signs of gradual movement toward somewhat greater exchange rate flexibility in many of the regional countries. There appears to be evidence of an apparent “fear of appreciation” which is manifested in asymmetric exchange rate intervention—i.e., a willingness to allow depreciations but reluctance to allow appreciations. This policy of effective exchange rate undervaluation is rather unorthodox from a neoclassical sense, but is consistent with a development policy centered on suppressing the price of non-tradable goods relative to tradables (i.e., real exchange rate undervaluation.

On exchange rate misalignments in the Eurozone's peripheral countries

Science.gov (United States)

Grochová, Ladislava; Plecitá, Klára

2013-10-01

In this paper we model equilibrium exchange rates for the Eurozone's countries on the basis of the Behavioural Equilibrium Exchange Rate approach, which assumes, that equilibrium exchange rates are in the long run affected by economic fundamentals. To assess the degree of exchange rate misalignment for the Eurozone's peripheral countries - Portugal, Ireland, Greece and Spain - the gap between the actual and the modelled equilibrium exchange rate value is calculated. Our results show that Spain, Portugal and Ireland had their real exchange rates in equilibrium when they joined the Eurozone; however their real exchange rates have been persistently overvalued since the beginning of the 2000s. Greece, on the other hand, has experienced diminishing undervaluation at the beginning of its membership in the Eurozone and since 2009 has exhibited an overvalued real exchange rate.

The Deceptive Resilience of Fixed Exchange Rates

OpenAIRE

Mushin, Jerry

2004-01-01

This paper is an examination of the experience of exchange-rate systems since 1978. Despite the accelerating trend in favour of floating exchange rates, a substantial minority of IMF members have continued to fix the value of their currencies. The recent incidence of each of the principal types of exchange-rate peg is described.

31 CFR 309.3 - Denominations and exchange.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Denominations and exchange. 309.3... Denominations and exchange. Treasury bills will be issued in denominations (maturity value) of $10,000, $15,000, $50,000, $100,000, $500,000, and $1,000,000. Exchanges from higher to lower and lower to higher...

Efficient Fair Exchange from Identity-Based Signature

Science.gov (United States)

Yum, Dae Hyun; Lee, Pil Joong

A fair exchange scheme is a protocol by which two parties Alice and Bob exchange items or services without allowing either party to gain advantages by quitting prematurely or otherwise misbehaving. To this end, modern cryptographic solutions use a semi-trusted arbitrator who involves only in cases where one party attempts to cheat or simply crashes. We call such a fair exchange scheme optimistic. When no registration is required between the signer and the arbitrator, we say that the fair exchange scheme is setup free. To date, the setup-free optimist fair exchange scheme under the standard RSA assumption was only possible from the generic construction of [12], which uses ring signatures. In this paper, we introduce a new setup-free optimistic fair exchange scheme under the standard RSA assumption. Our scheme uses the GQ identity-based signature and is more efficient than [12]. The construction can also be generalized by using various identity-based signature schemes. Our main technique is to allow each user to choose his (or her) own “random” public key in the identitybased signature scheme.

Heat exchanger tube inspection using ultrasonic arrays

International Nuclear Information System (INIS)

Meyer, P.A.; Carodiskey, T.J.

1986-01-01

Tubing used in industrial heat exchangers is often subject to failure caused by corrosion and cracking. Technical conferences are used as a forum in the steam generator industry to ensure that the failure mechanisms are well understood and that the quality of the heat exchanger is maintained. The quality of a heat exchanger can be thought of as its ability to operate to design specifications over its intended life. This is the motivation to inspect and evaluate these devices periodically. Inspection, however, normally requires shutdown of the heat exchanger which is costly but is much more acceptable than an unscheduled shutdown due to failure of a tube. Therefore, the degree of inspection is established by balancing the cost of inspection with the risk of a tube failure. Any method of reducing the cost of inspection will permit a higher degree of inspection and, therefore, improve heat exchanger quality. This paper reviews the design and performance of an improved method of ultrasonic inspection of heat exchanger tubing with emphasis on applications in the nuclear industry

Graphene-coated polymeric anion exchangers for ion chromatography

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kai; Cao, Minyi; Lou, Chaoyan [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Wu, Shuchao, E-mail: wushch2002@163.com [Zhejiang Institute of Geology and Mineral Resources, Hangzhou 310007 (China); Zhang, Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Zhi, Mingyu [Hangzhou Vocational & Technical College, Hangzhou, 310018 (China); Zhu, Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China)

2017-06-01

Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

Oxygen isotope exchange on palladium catalysts

International Nuclear Information System (INIS)

Kravchuk, L.S.; Beschetvertnaya, T.I.; Novorodskij, V.G.; Novikova, M.G.; Zaretskij, M.V.; Valieva, S.V.

1983-01-01

Oxygen heteromolecular isotope exchange on unreduced palladium catalysts, distingushing by metal content is studied. Content of 18 O in gaseous phase is eoual to 46%. Calculations of heteroexchange rates are conducted with decrease of the 18 O in the gaseous phase over solid sample. Method of oxygen thermodesorption has been used to establish that palladium, deposited on γ-Al 2 O 3 during exchange process is in oxidized state; in this case strength of Pd-O bond is determined by content dispersity) of the metal. It is shown that significant increase of exchange rate on the samples with Pd >> 0.5 mass.% content can be induced as by side decomposition reaction of its oxide and corresponding dilution of gaseous mixture by ''light'' oxygen so by possibility of exchange with oxygen of PdO phase

Charge exchange in galaxy clusters

Science.gov (United States)

Gu, Liyi; Mao, Junjie; de Plaa, Jelle; Raassen, A. J. J.; Shah, Chintan; Kaastra, Jelle S.

2018-03-01

Context. Though theoretically expected, the charge exchange emission from galaxy clusters has never been confidently detected. Accumulating hints were reported recently, including a rather marginal detection with the Hitomi data of the Perseus cluster. As previously suggested, a detection of charge exchange line emission from galaxy clusters would not only impact the interpretation of the newly discovered 3.5 keV line, but also open up a new research topic on the interaction between hot and cold matter in clusters. Aim. We aim to perform the most systematic search for the O VIII charge exchange line in cluster spectra using the RGS on board XMM-Newton. Methods: We introduce a sample of 21 clusters observed with the RGS. In order to search for O VIII charge exchange, the sample selection criterion is a >35σ detection of the O VIII Lyα line in the archival RGS spectra. The dominating thermal plasma emission is modeled and subtracted with a two-temperature thermal component, and the residuals are stacked for the line search. The systematic uncertainties in the fits are quantified by refitting the spectra with a varying continuum and line broadening. Results: By the residual stacking, we do find a hint of a line-like feature at 14.82 Å, the characteristic wavelength expected for oxygen charge exchange. This feature has a marginal significance of 2.8σ, and the average equivalent width is 2.5 × 10-4 keV. We further demonstrate that the putative feature can be barely affected by the systematic errors from continuum modeling and instrumental effects, or the atomic uncertainties of the neighboring thermal lines. Conclusions: Assuming a realistic temperature and abundance pattern, the physical model implied by the possible oxygen line agrees well with the theoretical model proposed previously to explain the reported 3.5 keV line. If the charge exchange source indeed exists, we expect that the oxygen abundance could have been overestimated by 8-22% in previous X

Interdependence and Exchange Rate Regimes in East Asia: Intra-regional Transmissions of Exchange Rate Policies after the Crisis (in Japanese)

OpenAIRE

OHNO Sanae; FUKUDA Shin-ichi

2003-01-01

Since the onset of the Asian crisis, what characterizes the East Asian exchange rates has been a topic of considerable discussion. In the pre-crisis period, the de facto pegs to the U.S. dollar sometimes destabilized the real "effective" exchange rates of these currencies. Several economists have, thus, proposed the desirability of intermediate exchange rate regimes in East Asia that might stabilize their effective exchange rates. The post-crisis experience in East Asia, however, taught us th...

RiverHeath: Neighborhood Loop Geothermal Exchange System

Energy Technology Data Exchange (ETDEWEB)

Geall, Mark [RiverHeath LLC, Appleton, WI (United States)

2016-07-11

The goal of the RiverHeath project is to develop a geothermal exchange system at lower capital infrastructure cost than current geothermal exchange systems. The RiverHeath system features an innovative design that incorporates use of the adjacent river through river-based heat exchange plates. The flowing water provides a tremendous amount of heat transfer. As a result, the installation cost of this geothermal exchange system is lower than more traditional vertical bore systems. Many urban areas are located along rivers and other waterways. RiverHeath will serve as a template for other projects adjacent to the water.

Microsoft® Exchange Server 2010 Inside Out

CERN Document Server

Redmond, Tony

2010-01-01

Dive into Exchange Server 2010 and SP1-and discover how to really put your messaging solutions to work! This well-organized and in-depth reference packs all the details you need to deploy and manage Exchange 2010, including hundreds of timesaving solutions, expert tips, and workarounds.Topics include preparing for the deployment of Exchange 2010; new features of Service Pack 1; using Remote PowerShell and the Exchange Management Shell; understanding how the new Role Based Access Control (RBAC) permissions model works and how to customize it to your requirements; the new high availability mode

Homogeneous deuterium exchange using rhenium and platinum chloride catalysts

International Nuclear Information System (INIS)

Fawdry, R.M.

1979-01-01

Previous studies of homogeneous hydrogen isotope exchange are mostly confined to one catalyst, the tetrachloroplatinite salt. Recent reports have indicated that chloride salts of iridium and rhodium may also be homogeneous exchange catalysts similar to the tetrachloroplatinite, but with much lower activities. Exchange by these homogeneous catalysts is frequently accompanied by metal precipitation with the termination of homogeneous exchange, particularly in the case of alkane exchange. The studies presented in this thesis describe two different approaches to overcome this limitation of homogeneous hydrogen isotope exchange catalysts. The first approach was to improve the stability of an existing homogeneous catalyst and the second was to develop a new homogeneous exchange catalyst which is free of the instability limitation

Application to ion exchange study of an interferometry method

International Nuclear Information System (INIS)

Platzer, R.

1960-01-01

The numerous experiments carried out on ion exchange between clay suspensions and solutions have so far been done by studying the equilibrium between the two phases; by this method it is very difficult to obtain the kinetic properties of the exchange reactions. At method consisting of observation with an interferential microscope using polarised white light shows up the variations in concentration which take place during the ion exchange between an ionic solution and a montmorillonite slab as well as between an ionic solution and a grain of organic ion exchanger. By analysing the results it will be possible to compare the exchange constants of organic ion exchangers with those of mineral ion exchangers. (author) [fr

International information exchange in fusion research

International Nuclear Information System (INIS)

Strickler, C.S.

1979-01-01

Formal and informal agreements exist between the US and several other countries, assuring the unrestricted exchange of magnetic fusion information. The Fusion Energy Library at Oak Ridge National Laboratory uses the US Department of Energy standard distribution system and exchange agreements to ensure the receipt of current reports. Selective dissemination of information, computer networks, and exchange programs are additional means for information gathering. The importance of these means as they relate to the fusion program in the US and specifically at ORNL is discussed

Timing Foreign Exchange Markets

Directory of Open Access Journals (Sweden)

Samuel W. Malone

2016-03-01

Full Text Available To improve short-horizon exchange rate forecasts, we employ foreign exchange market risk factors as fundamentals, and Bayesian treed Gaussian process (BTGP models to handle non-linear, time-varying relationships between these fundamentals and exchange rates. Forecasts from the BTGP model conditional on the carry and dollar factors dominate random walk forecasts on accuracy and economic criteria in the Meese-Rogoff setting. Superior market timing ability for large moves, more than directional accuracy, drives the BTGP’s success. We explain how, through a model averaging Monte Carlo scheme, the BTGP is able to simultaneously exploit smoothness and rough breaks in between-variable dynamics. Either feature in isolation is unable to consistently outperform benchmarks throughout the full span of time in our forecasting exercises. Trading strategies based on ex ante BTGP forecasts deliver the highest out-of-sample risk-adjusted returns for the median currency, as well as for both predictable, traded risk factors.

Characteristics of floc formation of anion and cation exchange resin in precoat filter using powdered ion exchange resin

International Nuclear Information System (INIS)

Adachi, Tetsurou; Sawa, Toshio; Shindoh, Toshikazu.

1989-01-01

The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of floc formation. The physical, chemical and electrochemical properties of powdered ion exchange resin were measured and the factors related to floc formation of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index. It was found that these factors were mixing ratio, nature of resins and particle size of resins. In addition, it was assumed on the bases of these results that the amount of resin floc was related to sum of the surface electric charges of both resins. The filling ratio of resin floc was related to their product by multiplication and an experimental expression was obtained. The specific settle volume of resin floc could then be simulated by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author)

Characteristics of floc formation of anion and cation exchange resin in precoat filter using powdered ion exchange resin

Energy Technology Data Exchange (ETDEWEB)

Adachi, Tetsurou (Nitto Denko Corp., Ibaraki, Osaka (Japan)); Sawa, Toshio; Shindoh, Toshikazu

1989-09-01

The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of floc formation. The physical, chemical and electrochemical properties of powdered ion exchange resin were measured and the factors related to floc formation of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index. It was found that these factors were mixing ratio, nature of resins and particle size of resins. In addition, it was assumed on the bases of these results that the amount of resin floc was related to sum of the surface electric charges of both resins. The filling ratio of resin floc was related to their product by multiplication and an experimental expression was obtained. The specific settle volume of resin floc could then be simulated by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author).

Ion exchange fiber by radiation grafting, 1

International Nuclear Information System (INIS)

Fujiwara, Kunio

1990-01-01

Radiation grafting is gaining attention as a method for producing high performance materials. This method can be applied to add functions to existing polymer plastics. The author participated in the research program on the production of ion exchange fiber by radiation grafting and its applicability at the Japan Atomic Energy Research Institute, Takasaki Radiation Chemistry Research Establishment. Consequently, it was clarified that it was possible to introduce the cation exchange group, represented by sulfonic and carboxyl groups, and the anion exchange group, represented by the quarternary ammonium group, to polypropylene fiber available on the market. The ion exchange capacity was able to be controlled by the degree of grafting, i.e. approximately up to 3 meq/g in both strong acid and strong base and approximately up to 5 meq/g in weak acid were obtained. The adsorption performance of ammonia, a representative malodorous substance, was also studied using test cation exchange fiber. The adsorption rate of H type strong acid cation exchange fiber was great, due to the H type having neutral reaction, and the adsorption capacity matched the ion exchange capacity. Although the Cu and Ni types features coordinated adsorption and their adsorption rates were from 1/2 to 1/3 of that of the H type, their adsorption capacities showed increase along with the metal adsorbed. (author)

Crystalline silicotitanates -- novel commercial cesium ion exchangers

International Nuclear Information System (INIS)

Braun, R.; Dangieri, T.J.; Fennelly, D.J.

1996-01-01

A new class of inorganic ion exchangers called crystalline silicotitanates (CST), invented by researchers at Sandia National Laboratories and Texas A ampersand M University, has been commercialized in a joint Sandia-UOP effort. The original developmental materials exhibited high selectivity for the ion exchange of cesium, strontium, and several other radionuclides from highly alkaline solutions containing molar concentrations of Na + . The materials also showed excellent chemical and radiation stability. These CST properties made them excellent candidates for treatment of solutions such as the Hanford tank supernates and other DOE radwastes. Sandia and UOP, under a Cooperative Research and Development Agreement (CRADA), developed CSTs in the powdered form and in an engineered form suitable for column ion exchange use. A continuous-flow, column ion exchange process is expected to be used to remove Cs and other radionuclides from the Hanford supernatant. The powder material invented by Sandia and Texas A ampersand M consists of submicron-size particles. It is not designed for column ion exchange but may be used in other applications such as batch waste processing. Data are also presented confirming the excellent stability of the commercial CSTs over a broad pH range and the high radiation stability of the exchangers. In addition, data are provided that demonstrate the high physical strength and attrition resistance of IONSIV reg-sign IE-911, critical properties for column ion exchange applications

Postsynthetic Doping of MnCl2 Molecules into Preformed CsPbBr3 Perovskite Nanocrystals via a Halide Exchange-Driven Cation Exchange.

Science.gov (United States)

Huang, Guangguang; Wang, Chunlei; Xu, Shuhong; Zong, Shenfei; Lu, Ju; Wang, Zhuyuan; Lu, Changgui; Cui, Yiping

2017-08-01

Unlike widely used postsynthetic halide exchange for CsPbX 3 (X is halide) perovskite nanocrystals (NCs), cation exchange of Pb is of a great challenge due to the rigid nature of the Pb cationic sublattice. Actually, cation exchange has more potential for rendering NCs with peculiar properties. Herein, a novel halide exchange-driven cation exchange (HEDCE) strategy is developed to prepare dually emitting Mn-doped CsPb(Cl/Br) 3 NCs via postsynthetic replacement of partial Pb in preformed perovskite NCs. The basic idea for HEDCE is that the partial cation exchange of Pb by Mn has a large probability to occur as a concomitant result for opening the rigid halide octahedron structure around Pb during halide exchange. Compared to traditional ionic exchange, HEDCE is featured by proceeding of halide exchange and cation exchange at the same time and lattice site. The time and space requirements make only MnCl 2 molecules (rather than mixture of Mn and Cl ions) capable of doping into perovskite NCs. This special molecular doping nature results in a series of unusual phenomenon, including long reaction time, core-shell structured mid states with triple emission bands, and dopant molecules composition-dependent doping process. As-prepared dual-emitting Mn-doped CsPb(Cl/Br) 3 NCs are available for ratiometric temperature sensing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contact isotopic- and contact ion-exchange between two adsorbents

International Nuclear Information System (INIS)

Bunzl, K.; Mohan, R.; Haimerl, M.

1975-01-01

The kinetics of contact ion exchange processes between an ion exchange membrane and resin ion exchange beads, stirred in pure water, was investigated. A general criterion was derived, which indicates whether diffusion of the ions between the intermingling electric double layers or the collision frequency between the two adsorbents is the rate dermining step. Since the latter process proved to be rate controlling under our experimental conditions, the corresponding rate equations were derived under various initial and boundary conditions. Experimentally, the kinetics of contact isotopic exchange of Cs + - and Na + -ions as well as of the reverse contact ion exchange process of Cs + -versus Na + -ions were investigated by using Na 22 and Cs 137 radioisotopes. The experiments reveal in quantitative accord with the theory that the rate of collision controlled contact ion exchange processes depends mainly on the 'exchange coefficient', the separation factor and the collision frequency. While the latter two quantities were determined independently by separate experiments, the 'exchange coefficient' was evaluated from a contact isotopic exchange experiment. (orig.) [de

The rho-exchange isovector parity-violating potential

International Nuclear Information System (INIS)

McKellar, B.H.J.

1979-01-01

It is shown that the rho-exchange isovector parity-violating potential is constrained by PCAC to be much weaker than the π-exchange potential and much weaker than recently proposed by Galic et al (J. Phys. G.; 5: L113 (1979)). This potential does not therefore provide a mechanism for suppressing enhanced neutral-current effects in the π-exchange potential. (author)

225-B ion exchange piping design documentation

International Nuclear Information System (INIS)

Prather, M.C.

1996-02-01

This document describes the interface between the planned permanent ion exchange piping system and the planned portable ion exchange system. This is part of the Waste Encapsulation and Storage Facility (WESF). In order to decouple this WESF from B-Plant and to improve recovery from a capsule leak, contaminated pool cell water will be recirculated through a portable ion exchange resin system

A re-examination of the exchange rate overshooting hypothesis ...

African Journals Online (AJOL)

Southern African Business Review ... This finding is inconsistent with the monetary model of exchange rate determination, which asserts that there is a long-run relationship between the exchange rate ... Key words: Exchange rates, monetary model, autoregressive distributed lag, cointegration, exchange rate overshooting ...

Catalyst for hydrogen-amine D exchange

International Nuclear Information System (INIS)

Holtslander, W.J.; Johnson, R.E.

1976-01-01

A process is claimed for deuterium isotopic enrichment (suitable for use in heavy water production) by amine-hydrogen exchange in which the exchange catalyst comprises a mixture of alkyl amides of two metals selected from the group consisting of the alkali metals. Catalyst mixtures comprising at least one of the alkali amides of lithium and potassium are preferred. At least one of the following benefits are obtained: decreased hydride formation, decreased thermal decomposition of alkyl amide, increased catalyst solubility in the amine phase, and increased exchange efficiency. 11 claims

Adsorption on mixtures of ion exchangers

International Nuclear Information System (INIS)

Triolo, R.; Lietzke, M.H.

1979-01-01

A theoretical study has been made of adsorption on mixtures of ion exchangers. The effect of variables such as the concentration of the ion being adsorbed, the concentration of the supporting electrolyte, loading, the values of the capacities and equilibrium constants for the various exchange processes, and the fraction of each adsorber in the mixture on the observed distribution coefficient has been investigated. A computer program has been written to facilitate the calculation of distribution coefficients for the adsorption of an ion on a given mixture of ion exchangers under a specified set of conditions

Heat Exchanger Support Bracket Design Calculations

International Nuclear Information System (INIS)

Rucinski, Russ

1995-01-01

This engineering note documents the design of the heat exchanger support brackets. The heat exchanger is roughly 40 feet long, 22 inches in diameter and weighs 6750 pounds. It will be mounted on two identical support brackets that are anchored to a concrete wall. The design calculations were done for one bracket supporting the full weight of the heat exchanger, rounded up to 6800 pounds. The design follows the American Institute of Steel Construction (AISC) Manual of steel construction, Eighth edition. All calculated stresses and loads on welds were below allowables.