WorldWideScience

Sample records for relaxed asymptotic conditions

  1. Asymptotic representation of relaxation oscillations in lasers

    CERN Document Server

    Grigorieva, Elena V

    2017-01-01

    In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.

  2. Optimal homotopy asymptotic method for solving fractional relaxation-oscillation equation

    Directory of Open Access Journals (Sweden)

    Mohammad Hamarsheh

    2015-11-01

    Full Text Available In this paper, an approximate analytical solution of linear fractional relaxation-oscillation equations in which the fractional derivatives are given in the Caputo sense, is obtained by the optimal homotopy asymptotic method (OHAM. The studied OHAM is based on minimizing the residual error. The results given by OHAM are compared with the exact solutions and the solutions obtained by generalized Taylor matrix method. The reliability and efficiency of the proposed approach are demonstrated in three examples with the aid of the symbolic algebra program Maple.

  3. Asymptotic conditions and conserved quantities

    International Nuclear Information System (INIS)

    Koul, R.K.

    1990-01-01

    Two problems have been investigated in this dissertation. The first one deals with the relationship between stationary space-times which are flat at null infinity and stationary space-times which are asymptotic flat at space-like infinity. It is shown that the stationary space-times which are asymptotically flat, in the Penrose sense, at null infinity, are asymptotically flat at space-like infinity in the Geroch sense and metric at space like infinity is at least C 1 . In the converse it is shown that the stationary space-times which are asymptotically flat at space like infinity, in the Beig sense, are asymptotically flat at null infinity in the Penrose sense. The second problem addressed deals with the theories of arbitrary dimensions. The theories treated are the ones which have fiber bundle structure, outside some compact region. For these theories the criterion for the choice of the background metric is specified, and the boundary condition for the initial data set (q ab , P ab ) is given in terms of the background metric. Having these boundary conditions it is shown that the symplectic structure and the constraint functionals are well defined. The conserved quantities associated with internal Killing vector fields are specified. Lastly the energy relative to a fixed background and the total energy of the theory have been given. It is also shown that the total energy of the theory is independent of the choice of the background

  4. Non-Weyl asymptotics for quantum graphs with general coupling conditions

    International Nuclear Information System (INIS)

    Davies, E Brian; Exner, Pavel; Lipovsky, JirI

    2010-01-01

    Inspired by a recent result of Davies and Pushnitski, we study resonance asymptotics of quantum graphs with general coupling conditions at the vertices. We derive a criterion for the asymptotics to be of a non-Weyl character. We show that for balanced vertices with permutation-invariant couplings the asymptotics is non-Weyl only in the case of Kirchhoff or anti-Kirchhoff conditions. While for graphs without permutation symmetry numerous examples of non-Weyl behaviour can be constructed. Furthermore, we present an insight into what makes the Kirchhoff/anti-Kirchhoff coupling particular from the resonance point of view. Finally, we demonstrate a generalization to quantum graphs with unequal edge weights.

  5. Asymptotic boundary conditions for dissipative waves: General theory

    Science.gov (United States)

    Hagstrom, Thomas

    1990-01-01

    An outstanding issue in the computational analysis of time dependent problems is the imposition of appropriate radiation boundary conditions at artificial boundaries. Accurate conditions are developed which are based on the asymptotic analysis of wave propagation over long ranges. Employing the method of steepest descents, dominant wave groups are identified and simple approximations to the dispersion relation are considered in order to derive local boundary operators. The existence of a small number of dominant wave groups may be expected for systems with dissipation. Estimates of the error as a function of domain size are derived under general hypotheses, leading to convergence results. Some practical aspects of the numerical construction of the asymptotic boundary operators are also discussed.

  6. Asymptotic boundary conditions for dissipative waves - General theory

    Science.gov (United States)

    Hagstrom, Thomas

    1991-01-01

    An outstanding issue in computational analysis of time dependent problems is the imposition of appropriate radiation boundary conditions at artificial boundaries. Accurate conditions are developed which are based on the asymptotic analysis of wave propagation over long ranges. Employing the method of steepest descents, dominant wave groups are identified and simple approximations to the dispersion relation are considered in order to derive local boundary operators. The existence of a small number of dominant wave groups may be expected for systems with dissipation. Estimates of the error as a function of domain size are derived under general hypotheses, leading to convergence results. Some practical aspects of the numerical construction of the asymptotic boundary operators are also discussed.

  7. Asymptotic description of two metastable processes of solidification for the case of large relaxation time

    International Nuclear Information System (INIS)

    Omel'yanov, G.A.

    1995-07-01

    The non-isothermal Cahn-Hilliard equations in the n-dimensional case (n = 2,3) are considered. The interaction length is proportional to a small parameter, and the relaxation time is proportional to a constant. The asymptotic solutions describing two metastable processes are constructed and justified. The soliton type solution describes the first stage of separation in alloy, when a set of ''superheated liquid'' appears inside the ''solid'' part. The Van der Waals type solution describes the free interface dynamics for large time. The smoothness of temperature is established for large time and the Mullins-Sekerka problem describing the free interface is derived. (author). 46 refs

  8. Asymptotic symmetries of Rindler space at the horizon and null infinity

    International Nuclear Information System (INIS)

    Chung, Hyeyoun

    2010-01-01

    We investigate the asymptotic symmetries of Rindler space at null infinity and at the event horizon using both systematic and ad hoc methods. We find that the approaches that yield infinite-dimensional asymptotic symmetry algebras in the case of anti-de Sitter and flat spaces only give a finite-dimensional algebra for Rindler space at null infinity. We calculate the charges corresponding to these symmetries and confirm that they are finite, conserved, and integrable, and that the algebra of charges gives a representation of the asymptotic symmetry algebra. We also use relaxed boundary conditions to find infinite-dimensional asymptotic symmetry algebras for Rindler space at null infinity and at the event horizon. We compute the charges corresponding to these symmetries and confirm that they are finite and integrable. We also determine sufficient conditions for the charges to be conserved on-shell, and for the charge algebra to give a representation of the asymptotic symmetry algebra. In all cases, we find that the central extension of the charge algebra is trivial.

  9. Periodic solutions of asymptotically linear Hamiltonian systems without twist conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Rong [Coll. of Mathematics and Physics, Nanjing Univ. of Information Science and Tech., Nanjing (China); Dept. of Mathematics, Southeast Univ., Nanjing (China); Zhang Dongfeng [Dept. of Mathematics, Southeast Univ., Nanjing (China)

    2010-05-15

    In dynamical system theory, especially in many fields of applications from mechanics, Hamiltonian systems play an important role, since many related equations in mechanics can be written in an Hamiltonian form. In this paper, we study the existence of periodic solutions for a class of Hamiltonian systems. By applying the Galerkin approximation method together with a result of critical point theory, we establish the existence of periodic solutions of asymptotically linear Hamiltonian systems without twist conditions. Twist conditions play crucial roles in the study of periodic solutions for asymptotically linear Hamiltonian systems. The lack of twist conditions brings some difficulty to the study. To the authors' knowledge, very little is known about the case, where twist conditions do not hold. (orig.)

  10. Asymptotic structure of the Einstein-Maxwell theory on AdS{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Alfredo [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile); Riquelme, Miguel [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción,Casilla 160-C, Concepción (Chile); Tempo, David [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile); Physique Théorique et Mathématique,Université Libre de Bruxelles and International Solvay Institutes,Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Troncoso, Ricardo [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile)

    2016-02-02

    The asymptotic structure of AdS spacetimes in the context of General Relativity coupled to the Maxwell field in three spacetime dimensions is analyzed. Although the fall-off of the fields is relaxed with respect to that of Brown and Henneaux, the variation of the canonical generators associated to the asymptotic Killing vectors can be shown to be finite once required to span the Lie derivative of the fields. The corresponding surface integrals then acquire explicit contributions from the electromagnetic field, and become well-defined provided they fulfill suitable integrability conditions, implying that the leading terms of the asymptotic form of the electromagnetic field are functionally related. Consequently, for a generic choice of boundary conditions, the asymptotic symmetries are broken down to ℝ⊗U(1)⊗U(1). Nonetheless, requiring compatibility of the boundary conditions with one of the asymptotic Virasoro symmetries, singles out the set to be characterized by an arbitrary function of a single variable, whose precise form depends on the choice of the chiral copy. Remarkably, requiring the asymptotic symmetries to contain the full conformal group selects a very special set of boundary conditions that is labeled by a unique constant parameter, so that the algebra of the canonical generators is given by the direct sum of two copies of the Virasoro algebra with the standard central extension and U(1). This special set of boundary conditions makes the energy spectrum of electrically charged rotating black holes to be well-behaved.

  11. Exact asymptotic relations for the effective response of linear viscoelastic heterogeneous media

    Science.gov (United States)

    Gallican, Valentin; Brenner, Renald; Suquet, Pierre

    2017-11-01

    This article addresses the asymptotic response of viscoelastic heterogeneous media in the frequency domain, at high and low frequencies, for different types of elementary linear viscoelastic constituents. By resorting to stationary principles for complex viscoelasticity and adopting a classification of the viscoelastic behaviours based on the nature of their asymptotic regimes, either elastic or viscous, four exact relations are obtained on the overall viscoelastic complex moduli in each case. Two relations are related to the asymptotic uncoupled heterogeneous problems, while the two remaining ones result from the viscoelastic coupling that manifests itself in the transient regime. These results also provide exact conditions on certain integrals in time of the effective relaxation spectrum. This general setting encompasses the results obtained in preceding studies on mixtures of Maxwell constituents [1,2]. xml:lang="fr"

  12. A Multivariate Asymmetric Long Memory Conditional Volatility Model with X, Regularity and Asymptotics

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2016-01-01

    textabstractThe paper derives a Multivariate Asymmetric Long Memory conditional volatility model with Exogenous Variables (X), or the MALMX model, with dynamic conditional correlations, appropriate regularity conditions, and associated asymptotic theory. This enables checking of internal consistency

  13. Asymptotics for Estimating Equations in Hidden Markov Models

    DEFF Research Database (Denmark)

    Hansen, Jørgen Vinsløv; Jensen, Jens Ledet

    Results on asymptotic normality for the maximum likelihood estimate in hidden Markov models are extended in two directions. The stationarity assumption is relaxed, which allows for a covariate process influencing the hidden Markov process. Furthermore a class of estimating equations is considered...

  14. Asymptotic solution of the non-isothermal Cahn-Hilliard system

    International Nuclear Information System (INIS)

    Omel'yanov, G.A.

    1995-05-01

    The non-isothermal Cahn-Hillard questions with a small parameter in the n-dimensional case (n = 2.3) are considered. The small parameter is proportional both to the relaxation time and to the linear scale of transition zone, so the large time process is examined. The asymptotic solution describing the free interface dynamics is constructed. As the small parameter tends to zero, the limiting solution satisfies the modified Stefan problem with corrected Gibbs-Thomson law. The justification of the asymptotic solution is proved. (author). 26 refs

  15. LSZ asymptotic condition and dynamic equations in quantum field theory

    International Nuclear Information System (INIS)

    Arkhipov, A.A.; Savrin, V.I.

    1983-01-01

    Some techniques that may be appropriate for the derivation of dynamic equations in quantum field theory are considered. A new method of deriving equations based on the use of LSZ asymptotic condition is described. It is proved that with the help of this method it becomes possible to obtain equations for wave functions both of scattering and bound states. Work is described in several papers under the dame title. The first paper is devoted to the Bethe-Salpeter equation

  16. Limiting conditions for operation relaxation program

    International Nuclear Information System (INIS)

    Merz, J.F.

    1985-01-01

    The purpose of this effort was to assess the impact of system maintenance unavailability on plant risk to provide technical justification for the relaxation of system limiting conditions for operation from three to seven days. The primary goal of the relaxation program is to allow for more thorough equipment maintenance. A potential increase in out-of-service time for a particular outage caused by the performance of more effective repairs will be counterbalanced by a probable decrease in the frequency in the outage rate of a component. Benefits resulting from an increase in allowed outage time include: (a) a potential reduction in total system out-of-service time, (b) a minimization of challenges to plant systems, and (c) a reduction in the number of emergency technical specification change requests. This program therefore offers an opportunity to more effectively manage plant maintenance and operation

  17. Relaxation of the single-slip condition in strain-gradient plasticity.

    Science.gov (United States)

    Anguige, Keith; Dondl, Patrick W

    2014-09-08

    We consider the variational formulation of both geometrically linear and geometrically nonlinear elasto-plasticity subject to a class of hard single-slip conditions. Such side conditions typically render the associated boundary-value problems non-convex. We show that, for a large class of non-smooth plastic distortions, a given single-slip condition (specification of Burgers vectors) can be relaxed by introducing a microstructure through a two-stage process of mollification and lamination. The relaxed model can be thought of as an aid to simulating macroscopic plastic behaviour without the need to resolve arbitrarily fine spatial scales.

  18. Asymptotic structure of isolated systems

    International Nuclear Information System (INIS)

    Schmidt, B.G.

    1979-01-01

    The main methods to formulate asymptotic flatness conditions are introduced and motivation and basic ideas are emphasized. Any asymptotic flatness condition proposed up to now describes space-times which behave somehow like Minkowski space, and a very explicit exposition of the structure at infinity of Minkowski space is given. This structure is used to describe the asymptotic behaviour of fields on Minkowski space in a frame-dependent way. The definition of null infinity for curved space-time according to Penrose is given and attempts to define spacelike infinity are outlined. The conformal bundle approach to the formulation of asymptotic behaviour is described and its relation to null and spacelike infinity is given, as far as known. (Auth.)

  19. Effects of distribution function nonequilibrium tails on relaxation and transfer processes in rarefied gases

    International Nuclear Information System (INIS)

    Grigoryev, Yu.N.; Mikhalitsyn, A.N.; Yanenko, N.N.

    1984-01-01

    Quantitative characteristics of the nonmonotone relaxation process are studied in a gas of pseudo-Maxwell molecules. Basic results are obtained by a direct numerical integration of the nonlinear Boltzmann equation. The evolution of initial distributions being finite or having exponential asymptotics of tails was researched. In particular, initial data obtained by selective excitation (absorption) against the Maxwell background encountered in laser physics problems have been considered. It is shown that under conditions of a developed effect of nonmonotone relaxation the overpopulation in the velocity range 4 <= upsilon <= 10 exceeds on the average 2-3 times the equilibrium value. For the given particles energy the excitation is preserved during t = 5/6 and the total relaxation time of the overpopulation wave reaches t asymptotically equals 20. The amplitudes and the relaxation time of overpopulation in the ''cupola'' region of distribution are substantially lower than in the case of a developed effect in the tail. The influence of the effect on the kinetics of threshold chemical reaction is studied. From the results it follows that in the process of nonmonotone relaxation the mean rates of binary threshold reactions can exceed more than twice the equilibrium values. This estimate is valid for all power like intermolecular repulsive potentials from the pseudo-Maxwell model up to rigid spheres. Time intervals over which the mean reaction rate exceeds considerably the equilibrium one make from 5 to 15 mean free path times increasing with the decrease in the potential ''rigidity''. (author)

  20. Asymptotic stability and blow up for a semilinear damped wave equation with dynamic boundary conditions

    KAUST Repository

    Gerbi, Stéphane

    2011-12-01

    In this paper we consider a multi-dimensional wave equation with dynamic boundary conditions, related to the KelvinVoigt damping. Global existence and asymptotic stability of solutions starting in a stable set are proved. Blow up for solutions of the problem with linear dynamic boundary conditions with initial data in the unstable set is also obtained. © 2011 Elsevier Ltd. All rights reserved.

  1. Asymptotic stability and blow up for a semilinear damped wave equation with dynamic boundary conditions

    KAUST Repository

    Gerbi, Sté phane; Said-Houari, Belkacem

    2011-01-01

    In this paper we consider a multi-dimensional wave equation with dynamic boundary conditions, related to the KelvinVoigt damping. Global existence and asymptotic stability of solutions starting in a stable set are proved. Blow up for solutions of the problem with linear dynamic boundary conditions with initial data in the unstable set is also obtained. © 2011 Elsevier Ltd. All rights reserved.

  2. A Sufficient Condition on Convex Relaxation of AC Optimal Power Flow in Distribution Networks

    DEFF Research Database (Denmark)

    Huang, Shaojun; Wu, Qiuwei; Wang, Jianhui

    2016-01-01

    This paper proposes a sufficient condition for the convex relaxation of AC Optimal Power Flow (OPF) in radial distribution networks as a second order cone program (SOCP) to be exact. The condition requires that the allowed reverse power flow is only reactive or active, or none. Under the proposed...... solution of the SOCP can be converted to an optimal solution of the original AC OPF. The efficacy of the convex relaxation to solve the AC OPF is demonstrated by case studies of an optimal multi-period planning problem of electric vehicles (EVs) in distribution networks....... sufficient condition, the feasible sub-injection region (power injections of nodes excluding the root node) of the AC OPF is convex. The exactness of the convex relaxation under the proposed condition is proved through constructing a group of monotonic series with limits, which ensures that the optimal...

  3. Asymptotics for the conditional-sum-of-squares estimator in multivariate fractional time series models

    DEFF Research Database (Denmark)

    Ørregård Nielsen, Morten

    This paper proves consistency and asymptotic normality for the conditional-sum-of-squares estimator, which is equivalent to the conditional maximum likelihood estimator, in multivariate fractional time series models. The model is parametric and quite general, and, in particular, encompasses...... the multivariate non-cointegrated fractional ARIMA model. The novelty of the consistency result, in particular, is that it applies to a multivariate model and to an arbitrarily large set of admissible parameter values, for which the objective function does not converge uniformly in probablity, thus making...

  4. Power-law relaxation in human violent conflicts

    Science.gov (United States)

    Picoli, Sergio; Antonio, Fernando J.; Itami, Andreia S.; Mendes, Renio S.

    2017-08-01

    We study relaxation patterns of violent conflicts after bursts of activity. Data were obtained from available catalogs on the conflicts in Iraq, Afghanistan and Northern Ireland. We find several examples in each catalog for which the observed relaxation curves can be well described by an asymptotic power-law decay (the analog of the Omori's law in geophysics). The power-law exponents are robust, nearly independent of the conflict. We also discuss the exogenous or endogenous nature of the shocks. Our results suggest that violent conflicts share with earthquakes and other natural and social phenomena a common feature in the dynamics of aftershocks.

  5. Asymptotic numbers, asymptotic functions and distributions

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1979-07-01

    The asymptotic functions are a new type of generalized functions. But they are not functionals on some space of test-functions as the distributions of Schwartz. They are mappings of the set denoted by A into A, where A is the set of the asymptotic numbers introduced by Christov. On its part A is a totally-ordered set of generalized numbers including the system of real numbers R as well as infinitesimals and infinitely large numbers. Every two asymptotic functions can be multiplied. On the other hand, the distributions have realizations as asymptotic functions in a certain sense. (author)

  6. Low-temperature strain ageing in In-Pb alloys under stress relaxation conditions

    International Nuclear Information System (INIS)

    Fomenko, L.S.

    2000-01-01

    The dynamic strain ageing (DSA) of In-Pb (6 and 8 at. % Pb) substitutional solid solution single crystals is studied at temperatures 77-205 K under stress relaxation conditions. The dependences of the stress increment after relaxation connected with DSA on stress relaxation time, stress relaxation rate at the end of the relaxation, temperature, alloy content, flow stress, and strain are determined. It is shown that the DSA kinetic is described by a Harper-type equation with the exponent equal to 1/3 and a low activation energy value (0.3-0.34 eV). This provides a low temperature of the DSA onset (∼ 0.17 T m , where T m is the melt temperature) and is evidence of pipe-mode diffusion. It is supposed that the obstacles to dislocation motion in the crystals studied consist of the groups of solutes, and the strength of the obstacles increases during the DSA due to the pipe diffusion of the solute atoms along the dislocations

  7. Asymptotic kinetic theory of magnetized plasmas: quasi-particle concept

    International Nuclear Information System (INIS)

    Sosenko, P.P.; Zagorodny, A.H.

    2004-01-01

    The asymptotic kinetic theory of magnetized plasmas is elaborated within the context of general statistical approach and asymptotic methods, developed by M. Krylov and M. Bohol'ubov, for linear and non-linear dynamic systems with a rapidly rotating phase. The quasi-particles are introduced already on the microscopic level. Asymptotic expansions enable to close the description for slow processes, and to relate consistently particles and guiding centres to quasi-particles. The kinetic equation for quasi-particles is derived. It makes a basis for the reduced description of slow collective phenomena in the medium. The kinetic equation for quasi-particles takes into account self-consistent interaction fields, quasi-particle collisions and collective-fluctuation-induced relaxation of quasi-particle distribution function. The relationships between the distribution functions for particles, guiding centres and quasi-particles are derived taking into account fluctuations, which can be especially important in turbulent states. In this way macroscopic (statistical) particle properties can be obtained from those of quasi-particles in the general case of non-equilibrium. (authors)

  8. Effect of Temper Condition on Stress Relaxation Behavior of an Aluminum Copper Lithium Alloy

    Science.gov (United States)

    Mishra, Sumeet; Beura, Vikrant Kumar; Singh, Amit; Yadava, Manasij; Nayan, Niraj

    2018-04-01

    Deformation behavior of an Al-Cu-Li alloy in different temper conditions (solutionized and T8) is investigated using stress relaxation tests. Fundamental parameters such as the apparent and physical activation volume, strain rate sensitivity, effective stress, and exhaustion rate of mobile dislocation density are determined from single and multiple relaxation tests. It was found that dislocation-dislocation interaction controls the kinetics of plastic deformation in the solutionized sample, whereas dislocation-precipitate interaction is the overriding factor in the presence of T1 precipitates. The apparent activation volume was found to be significantly lower in the presence of T1 precipitates compared with solutionized samples. Strain rate sensitivity and effective stress were found to be higher in the presence of T1 precipitates. In addition, multiple relaxation tests showed that irrespective of microstructural features (solutes, semi-coherent precipitates), the mobile dislocation density reduces during the relaxation period. Further evidence regarding reduction in mobile dislocation density is obtained from uniaxial tensile tests carried out after stress relaxation tests, where both solutionized and T8 samples show an increase in strength. Additional discussion on relaxation strain is included to provide a complete overview regarding the time-dependent deformation behavior of the Al-Cu-Li alloy in different temper conditions.

  9. On maximal surfaces in asymptotically flat space-times

    International Nuclear Information System (INIS)

    Bartnik, R.; Chrusciel, P.T.; O Murchadha, N.

    1990-01-01

    Existence of maximal and 'almost maximal' hypersurfaces in asymptotically flat space-times is established under boundary conditions weaker than those considered previously. We show in particular that every vacuum evolution of asymptotically flat data for Einstein equations can be foliated by slices maximal outside a spatially compact set and that every (strictly) stationary asymptotically flat space-time can be foliated by maximal hypersurfaces. Amongst other uniqueness results, we show that maximal hypersurface can be used to 'partially fix' an asymptotic Poincare group. (orig.)

  10. Cosmic censorship, persistent curvature and asymptotic causal pathology

    International Nuclear Information System (INIS)

    Newman, R.P.A.C.

    1984-01-01

    The paper examines cosmic censorship in general relativity theory. Conformally flat space-times; persistent curvature; weakly asymptotically simple and empty asymptotes; censorship conditions; and the censorship theorem; are all discussed. (U.K.)

  11. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  12. A quantum kinematics for asymptotically flat gravity

    Science.gov (United States)

    Campiglia, Miguel; Varadarajan, Madhavan

    2015-07-01

    We construct a quantum kinematics for asymptotically flat gravity based on the Koslowski-Sahlmann (KS) representation. The KS representation is a generalization of the representation underlying loop quantum gravity (LQG) which supports, in addition to the usual LQG operators, the action of ‘background exponential operators’, which are connection dependent operators labelled by ‘background’ su(2) electric fields. KS states have, in addition to the LQG state label corresponding to one dimensional excitations of the triad, a label corresponding to a ‘background’ electric field that describes three dimensional excitations of the triad. Asymptotic behaviour in quantum theory is controlled through asymptotic conditions on the background electric fields that label the states and the background electric fields that label the operators. Asymptotic conditions on the triad are imposed as conditions on the background electric field state label while confining the LQG spin net graph labels to compact sets. We show that KS states can be realised as wave functions on a quantum configuration space of generalized connections and that the asymptotic behaviour of each such generalized connection is determined by that of the background electric fields which label the background exponential operators. Similar to the spatially compact case, the Gauss law and diffeomorphism constraints are then imposed through group averaging techniques to obtain a large sector of gauge invariant states. It is shown that this sector supports a unitary action of the group of asymptotic rotations and translations and that, as anticipated by Friedman and Sorkin, for appropriate spatial topology, this sector contains states that display fermionic behaviour under 2π rotations.

  13. Heat Kernel Asymptotics of Zaremba Boundary Value Problem

    Energy Technology Data Exchange (ETDEWEB)

    Avramidi, Ivan G. [Department of Mathematics, New Mexico Institute of Mining and Technology (United States)], E-mail: iavramid@nmt.edu

    2004-03-15

    The Zaremba boundary-value problem is a boundary value problem for Laplace-type second-order partial differential operators acting on smooth sections of a vector bundle over a smooth compact Riemannian manifold with smooth boundary but with discontinuous boundary conditions, which include Dirichlet boundary conditions on one part of the boundary and Neumann boundary conditions on another part of the boundary. We study the heat kernel asymptotics of Zaremba boundary value problem. The construction of the asymptotic solution of the heat equation is described in detail and the heat kernel is computed explicitly in the leading approximation. Some of the first nontrivial coefficients of the heat kernel asymptotic expansion are computed explicitly.

  14. Relaxation Cycles in a Generalized Neuron Model with Two Delays

    Directory of Open Access Journals (Sweden)

    S. D. Glyzin

    2013-01-01

    Full Text Available A method of modeling the phenomenon of bursting behavior in neural systems based on delay equations is proposed. A singularly perturbed scalar nonlinear differentialdifference equation of Volterra type is a mathematical model of a neuron and a separate pulse containing one function without delay and two functions with different lags. It is established that this equation, for a suitable choice of parameters, has a stable periodic motion with any preassigned number of bursts in the time interval of the period length. To prove this assertion we first go to a relay-type equation and then determine the asymptotic solutions of a singularly perturbed equation. On the basis of this asymptotics the Poincare operator is constructed. The resulting operator carries a closed bounded convex set of initial conditions into itself, which suggests that it has at least one fixed point. The Frechet derivative evaluation of the succession operator, made in the paper, allows us to prove the uniqueness and stability of the resulting relax of the periodic solution.

  15. Criteria for exponential asymptotic stability in the large of ...

    African Journals Online (AJOL)

    The purpose of this study is to provide necessary and sufficient conditions for exponential asymptotic stability in the large and uniform asymptotic stability of perturbations of linear systems with unbounded delays. A strong relationship is established between the two types of asymptotic stability. It is found that if the ...

  16. Komar integrals in asymptotically anti-de Sitter space-times

    International Nuclear Information System (INIS)

    Magnon, A.

    1985-01-01

    Recently, boundary conditions governing the asymptotic behavior of the gravitational field in the presence of a negative cosmological constant have been introduced using Penrose's conformal techniques. The subsequent analysis has led to expressions of conserved quantities (associated with asymptotic symmetries) involving asymptotic Weyl curvature. On the other hand, if the underlying space-time is equipped with isometries, a generalization of the Komar integral which incorporates the cosmological constant is also available. Thus, in the presence of an isometry, one is faced with two apparently unrelated definitions. It is shown that these definitions agree. This coherence supports the choice of boundary conditions for asymptotically anti-de Sitter space-times and reinforces the definitions of conserved quantities

  17. Exactly solvable nonequilibrium Langevin relaxation of a trapped nanoparticle

    International Nuclear Information System (INIS)

    Salazar, Domingos S P; Lira, Sérgio A

    2016-01-01

    In this work, we study the nonequilibrium statistical properties of the relaxation dynamics of a nanoparticle trapped in a harmonic potential. We report an exact time-dependent analytical solution to the Langevin dynamics that arises from the stochastic differential equation of our system’s energy in the underdamped regime. By utilizing this stochastic thermodynamics approach, we are able to completely describe the heat exchange process between the nanoparticle and the surrounding environment. As an important consequence of our results, we observe the validity of the heat exchange fluctuation theorem in our setup, which holds for systems arbitrarily far from equilibrium conditions. By extending our results for the case of N noninterating nanoparticles, we perform analytical asymptotic limits and direct numerical simulations that corroborate our analytical predictions. (paper)

  18. Modeling the outflow of liquid with initial supercritical parameters using the relaxation model for condensation

    Directory of Open Access Journals (Sweden)

    Lezhnin Sergey

    2017-01-01

    Full Text Available The two-temperature model of the outflow from a vessel with initial supercritical parameters of medium has been realized. The model uses thermodynamic non-equilibrium relaxation approach to describe phase transitions. Based on a new asymptotic model for computing the relaxation time, the outflow of water with supercritical initial pressure and super- and subcritical temperatures has been calculated.

  19. The PN theory as an asymptotic limit of transport theory in planar geometry. 1

    International Nuclear Information System (INIS)

    Larsen, E.W.; Pomraning, G.C.

    1991-01-01

    In this paper the P N theory is shown to be an asymptotic limit of transport theory for an optically thick planar-geometry system with small absorption and highly anisotropic scattering. The asymptotic analysis shows that the solution in the interior of the system is described by the standard P N equations for which initial, boundary, and interface conditions are determined by asymptotic initial, boundary layer, and interface layer calculations. The asymptotic initial, (reflecting) boundary, and interface conditions for the P N equations agree with conventional formulations. However, at a boundary having a prescribed incident flux, the asymptotic boundary layer analysis yields P N boundary conditions that differ from previous formulations. Numerical transport and P N results are presented to substantiate this asymptotic theory

  20. Conformal Phase Diagram of Complete Asymptotically Free Theories

    DEFF Research Database (Denmark)

    Pica, Claudio; Ryttov, Thomas A.; Sannino, Francesco

    2017-01-01

    function. We provide the general conditions that the beta function coefficients must abide for the theory to be completely asymptotically free while simultaneously possessing an infrared stable fixed point. We also uncover special trajectories in coupling space along which some couplings are both...... asymptotically safe and infrared conformal....

  1. Asymptotic representation theorems for poverty indices | Lo | Afrika ...

    African Journals Online (AJOL)

    Abstract. We set general conditions under which the general poverty index, which summarizes all the available indices, is asymptotically represented with some empirical processes. This representation theorem offers a general key, in most directions, for the asymptotic of the bulk of poverty indices and issues in poverty ...

  2. Asymptotically anti-de Sitter spacetimes in topologically massive gravity

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2009-01-01

    We consider asymptotically anti-de Sitter spacetimes in three-dimensional topologically massive gravity with a negative cosmological constant, for all values of the mass parameter μ (μ≠0). We provide consistent boundary conditions that accommodate the recent solutions considered in the literature, which may have a slower falloff than the one relevant for general relativity. These conditions are such that the asymptotic symmetry is in all cases the conformal group, in the sense that they are invariant under asymptotic conformal transformations and that the corresponding Virasoro generators are finite. It is found that, at the chiral point |μl|=1 (where l is the anti-de Sitter radius), allowing for logarithmic terms (absent for general relativity) in the asymptotic behavior of the metric makes both sets of Virasoro generators nonzero even though one of the central charges vanishes.

  3. GENERAL DECAY FOR A DIFFERENTIAL INCLUSION OF KIRCHHOFF TYPE WITH A MEMORY CONDITION AT THE BOUNDARY

    Institute of Scientific and Technical Information of China (English)

    Jum-Ran KANG

    2014-01-01

    In this article, we consider a differential inclusion of Kirchhoff type with a memory condition at the boundary. We prove the asymptotic behavior of the corresponding solutions. For a wider class of relaxation functions, we establish a more general decay result, from which the usual exponential and polynomial decay rates are only special cases.

  4. Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.B.; Korneev, V.A.; Goloshubin, G.M.; Patzek, T.W.

    2004-04-14

    Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the square root of the product of the reservoir fluidmobility and the frequency of the signal. The dependence of this scalingon the dynamic Darcy's law relaxation time is investigated as well.Derivation of the main equations of the theory of poroelasticity from thedynamic filtration theory reveals that this relaxation time isproportional to Biot's tortuosity parameter.

  5. More on asymptotically anti-de Sitter spaces in topologically massive gravity

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2010-01-01

    Recently, the asymptotic behavior of three-dimensional anti-de Sitter (AdS) gravity with a topological mass term was investigated. Boundary conditions were given that were asymptotically invariant under the two dimensional conformal group and that included a falloff of the metric sufficiently slow to consistently allow pp-wave type of solutions. Now, pp waves can have two different chiralities. Above the chiral point and at the chiral point, however, only one chirality can be considered, namely, the chirality that has the milder behavior at infinity. The other chirality blows up faster than AdS and does not define an asymptotically AdS spacetime. By contrast, both chiralities are subdominant with respect to the asymptotic behavior of AdS spacetime below the chiral point. Nevertheless, the boundary conditions given in the earlier treatment only included one of the two chiralities (which could be either one) at a time. We investigate in this paper whether one can generalize these boundary conditions in order to consider simultaneously both chiralities below the chiral point. We show that this is not possible if one wants to keep the two-dimensional conformal group as asymptotic symmetry group. Hence, the boundary conditions given in the earlier treatment appear to be the best possible ones compatible with conformal symmetry. In the course of our investigations, we provide general formulas controlling the asymptotic charges for all values of the topological mass (not just below the chiral point).

  6. On real statistics of relaxation in gases

    Science.gov (United States)

    Kuzovlev, Yu. E.

    2016-02-01

    By example of a particle interacting with ideal gas, it is shown that the statistics of collisions in statistical mechanics at any value of the gas rarefaction parameter qualitatively differ from that conjugated with Boltzmann's hypothetical molecular chaos and kinetic equation. In reality, the probability of collisions of the particle in itself is random. Because of that, the relaxation of particle velocity acquires a power-law asymptotic behavior. An estimate of its exponent is suggested on the basis of simple kinematic reasons.

  7. Relaxation strain measurements in cellular dislocation structures

    International Nuclear Information System (INIS)

    Tsai, C.Y.; Quesnel, D.J.

    1984-01-01

    The conventional picture of what happens during a stress relaxation usually involves imagining the response of a single dislocation to a steadily decreasing stress. The velocity of this dislocation decreases with decreasing stress in such a way that we can measure the stress dependence of the dislocation velocity. Analysis of the data from a different viewpoint enables us to calculate the apparent activation volume for the motion of the dislocation under the assumption of thermally activated glie. Conventional thinking about stress relaxation, however, does not consider the eventual fate of this dislocation. If the stress relaxes to a low enough level, it is clear that the dislocation must stop. This is consistent with the idea that we can determine the stress dependence of the dislocation velocity from relaxation data only for those cases where the dislocation's velocity is allowed to approach zero asymptotically, in short, for those cases where the dislocation never stops. This conflict poses a dilemma for the experimentalist. In real crystals, however, obstacles impede the dislocation's progress so that those dislocations which are stopped at a given stress will probably never resume motion under the influence of the steadily declining stress present during relaxation. Thus one could envision stress relaxation as a process of exhaustion of mobile dislocations, rather than a process of decreasing dislocation velocity. Clearly both points of view have merit and in reality both mechanisms contribute to the phenomena

  8. Asymptotic solutions of diffusion models for risk reserves

    Directory of Open Access Journals (Sweden)

    S. Shao

    2003-01-01

    Full Text Available We study a family of diffusion models for risk reserves which account for the investment income earned and for the inflation experienced on claim amounts. After we defined the process of the conditional probability of ruin over finite time and imposed the appropriate boundary conditions, classical results from the theory of diffusion processes turn the stochastic differential equation to a special class of initial and boundary value problems defined by a linear diffusion equation. Armed with asymptotic analysis and perturbation theory, we obtain the asymptotic solutions of the diffusion models (possibly degenerate governing the conditional probability of ruin over a finite time in terms of interest rate.

  9. Quasi-extended asymptotic functions

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1979-01-01

    The class F of ''quasi-extended asymptotic functions'' is introduced. It contains all extended asymptotic functions as well as some new asymptotic functions very similar to the Schwartz distributions. On the other hand, every two quasiextended asymptotic functions can be multiplied as opposed to the Schwartz distributions; in particular, the square delta 2 of an asymptotic function delta similar to Dirac's delta-function, is constructed as an example

  10. A Stabilized Incompressible SPH Method by Relaxing the Density Invariance Condition

    Directory of Open Access Journals (Sweden)

    Mitsuteru Asai

    2012-01-01

    Full Text Available A stabilized Incompressible Smoothed Particle Hydrodynamics (ISPH is proposed to simulate free surface flow problems. In the ISPH, pressure is evaluated by solving pressure Poisson equation using a semi-implicit algorithm based on the projection method. Even if the pressure is evaluated implicitly, the unrealistic pressure fluctuations cannot be eliminated. In order to overcome this problem, there are several improvements. One is small compressibility approach, and the other is introduction of two kinds of pressure Poisson equation related to velocity divergence-free and density invariance conditions, respectively. In this paper, a stabilized formulation, which was originally proposed in the framework of Moving Particle Semi-implicit (MPS method, is applied to ISPH in order to relax the density invariance condition. This formulation leads to a new pressure Poisson equation with a relaxation coefficient, which can be estimated by a preanalysis calculation. The efficiency of the proposed formulation is tested by a couple of numerical examples of dam-breaking problem, and its effects are discussed by using several resolution models with different particle initial distances. Also, the effect of eddy viscosity is briefly discussed in this paper.

  11. Establishment of a colony of Anastrepha ludens (Diptera: Tephritidae) under relaxed mass-rearing conditions in Mexico

    International Nuclear Information System (INIS)

    Orozco-Davila, Dina; Hernandez, Refugio; Solis, Eduardo; Quintero, J. Luis; Dominguez, Julio

    2006-01-01

    Several studies have suggested that maintaining a line of insects under laboratory conditions reduces their biological attributes. With this principle in mind, the mass production of Anastrepha ludens originating from a colony raised under relaxed rearing conditions was evaluated over a period of three years. The results of the evaluation indicated that insects kept under these conditions reached their larval maturity in 10 days, and attained a greater weight, which has a direct influence on pupal quality. In adult cages having a fly density of 70,000 individuals, there was a lower level of stress which favored fecundity. Fertility was apparently not affected by the cage density. These results suggest that keeping a production line under relaxed conditions optimizes insect production and promotes higher quality. (author)

  12. Establishment of a colony of Anastrepha ludens (Diptera: Tephritidae) under relaxed mass-rearing conditions in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Orozco-Davila, Dina; Hernandez, Refugio; Solis, Eduardo; Quintero, J. Luis; Dominguez, Julio, E-mail: dorozco1@prodigy.net.m [United States Department of Agriculture, Gainesville, FL (United States). Agricultural Research Service. Center for Medical, Agricultural, and Veterinary Entomology; Sigma Space Corporation, MD(United States); Programa Moscamed Moscafrut-Desarrollo de Metodos, Chiapas (Mexico)

    2006-07-01

    Several studies have suggested that maintaining a line of insects under laboratory conditions reduces their biological attributes. With this principle in mind, the mass production of Anastrepha ludens originating from a colony raised under relaxed rearing conditions was evaluated over a period of three years. The results of the evaluation indicated that insects kept under these conditions reached their larval maturity in 10 days, and attained a greater weight, which has a direct influence on pupal quality. In adult cages having a fly density of 70,000 individuals, there was a lower level of stress which favored fecundity. Fertility was apparently not affected by the cage density. These results suggest that keeping a production line under relaxed conditions optimizes insect production and promotes higher quality. (author)

  13. Error estimates in horocycle averages asymptotics: challenges from string theory

    NARCIS (Netherlands)

    Cardella, M.A.

    2010-01-01

    For modular functions of rapid decay, a classical result connects the error estimate in their long horocycle average asymptotic to the Riemann hypothesis. We study similar asymptotics, for modular functions with not that mild growing conditions, such as of polynomial growth and of exponential growth

  14. Dynamic mesh adaptation for front evolution using discontinuous Galerkin based weighted condition number relaxation

    International Nuclear Information System (INIS)

    Greene, Patrick T.; Schofield, Samuel P.; Nourgaliev, Robert

    2017-01-01

    A new mesh smoothing method designed to cluster cells near a dynamically evolving interface is presented. The method is based on weighted condition number mesh relaxation with the weight function computed from a level set representation of the interface. The weight function is expressed as a Taylor series based discontinuous Galerkin projection, which makes the computation of the derivatives of the weight function needed during the condition number optimization process a trivial matter. For cases when a level set is not available, a fast method for generating a low-order level set from discrete cell-centered fields, such as a volume fraction or index function, is provided. Results show that the low-order level set works equally well as the actual level set for mesh smoothing. Meshes generated for a number of interface geometries are presented, including cases with multiple level sets. Lastly, dynamic cases with moving interfaces show the new method is capable of maintaining a desired resolution near the interface with an acceptable number of relaxation iterations per time step, which demonstrates the method's potential to be used as a mesh relaxer for arbitrary Lagrangian Eulerian (ALE) methods.

  15. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Directory of Open Access Journals (Sweden)

    J. W. Zhang

    2017-10-01

    Full Text Available As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC. In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  16. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Science.gov (United States)

    Zhang, J. W.; Zhou, T. C.; Wang, J. X.; Yang, X. F.; Zhu, F.; Tian, L. M.; Liu, R. T.

    2017-10-01

    As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC). In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  17. Theory of collisions between an atom and a diatomic molecule in the body-fixed coordinate system.)/sup a/ I. Coupled differential equation and asymptotic boundary conditions

    International Nuclear Information System (INIS)

    Choi, B.H.; Poe, R.T.; Tang, K.T.

    1978-01-01

    The body-fixed (BF) formulation for atom--diatom scatterings is developed to the extent that one can use it to perform accurate close-coupling calculation, without introducing further approximation except truncating a finite basis set of the target molecular wave function, on the same ground as one use the space-fixed (SF) formulation. In this formulation, the coupled differential equations are solved an the boundary conditions matched entirely in the BF coordinate system. A unitary transformation is used to obtain both the coupled differential equation and the boundary condition in BF system system from SF system. All properties of the solution with respect to parity are derived entirely from the transformation, without using the parity eignfunctions of the BF frame. Boundary conditions that yield the scattering (S) matrix and the reactance (R) matrix are presented for each parity in both the far asymptotic region (where the interaction and the centrifugal potentials are both negligible) and the near asymptotic region (where the interaction potential is negligible but the centrifugal potential is not). While our differential equations are the same as those derived by others with different methods, our asymptotic boundary conditions disagree with some existing ones. With a given form of the BF coupled differential equations, the acceptable boundary conditions are discussed

  18. ASYMPTOTICS OF a PARTICLES TRANSPORT PROBLEM

    Directory of Open Access Journals (Sweden)

    Kuzmina Ludmila Ivanovna

    2017-11-01

    Full Text Available Subject: a groundwater filtration affects the strength and stability of underground and hydro-technical constructions. Research objectives: the study of one-dimensional problem of displacement of suspension by the flow of pure water in a porous medium. Materials and methods: when filtering a suspension some particles pass through the porous medium, and some of them are stuck in the pores. It is assumed that size distributions of the solid particles and the pores overlap. In this case, the main mechanism of particle retention is a size-exclusion: the particles pass freely through the large pores and get stuck at the inlet of the tiny pores that are smaller than the particle diameter. The concentrations of suspended and retained particles satisfy two quasi-linear differential equations of the first order. To solve the filtration problem, methods of nonlinear asymptotic analysis are used. Results: in a mathematical model of filtration of suspensions, which takes into account the dependence of the porosity and permeability of the porous medium on concentration of retained particles, the boundary between two phases is moving with variable velocity. The asymptotic solution to the problem is constructed for a small filtration coefficient. The theorem of existence of the asymptotics is proved. Analytical expressions for the principal asymptotic terms are presented for the case of linear coefficients and initial conditions. The asymptotics of the boundary of two phases is given in explicit form. Conclusions: the filtration problem under study can be solved analytically.

  19. Global asymptotic stability of delayed Cohen-Grossberg neural networks

    International Nuclear Information System (INIS)

    Wu Wei; Cui Baotong; Huang Min

    2007-01-01

    In this letter, the global asymptotic stability of a class of Cohen-Grossberg neural networks with time-varying delays is discussed. A new set of sufficient conditions for the neural networks are proposed to guarantee the global asymptotic convergence. Our criteria represent an extension of the existing results in literatures. An example is also presented to compare our results with the previous results

  20. Asymptotic stability of a coupled advection-diffusion-reaction system arising in bioreactor processes

    Directory of Open Access Journals (Sweden)

    Maria Crespo

    2017-08-01

    Full Text Available In this work, we present an asymptotic analysis of a coupled system of two advection-diffusion-reaction equations with Danckwerts boundary conditions, which models the interaction between a microbial population (e.g., bacteria, called biomass, and a diluted organic contaminant (e.g., nitrates, called substrate, in a continuous flow bioreactor. This system exhibits, under suitable conditions, two stable equilibrium states: one steady state in which the biomass becomes extinct and no reaction is produced, called washout, and another steady state, which corresponds to the partial elimination of the substrate. We use the linearization method to give sufficient conditions for the linear asymptotic stability of the two stable equilibrium configurations. Finally, we compare our asymptotic analysis with the usual asymptotic analysis associated to the continuous bioreactor when it is modeled with ordinary differential equations.

  1. Relaxation model for extended magnetohydrodynamics: Comparison to magnetohydrodynamics for dense Z-pinches

    International Nuclear Information System (INIS)

    Seyler, C. E.; Martin, M. R.

    2011-01-01

    It is shown that the two-fluid model under a generalized Ohm's law formulation and the resistive magnetohydrodynamics (MHD) can both be described as relaxation systems. In the relaxation model, the under-resolved stiff source terms constrain the dynamics of a set of hyperbolic equations to give the correct asymptotic solution. When applied to the collisional two-fluid model, the relaxation of fast time scales associated with displacement current and finite electron mass allows for a natural transition from a system where Ohm's law determines the current density to a system where Ohm's law determines the electric field. This result is used to derive novel algorithms, which allow for multiscale simulation of low and high frequency extended-MHD physics. This relaxation formulation offers an efficient way to implicitly advance the Hall term and naturally simulate a plasma-vacuum interface without invoking phenomenological models. The relaxation model is implemented as an extended-MHD code, which is used to analyze pulsed power loads such as wire arrays and ablating foils. Two-dimensional simulations of pulsed power loads are compared for extended-MHD and MHD. For these simulations, it is also shown that the relaxation model properly recovers the resistive-MHD limit.

  2. Role of exponential type random invexities for asymptotically sufficient efficiency conditions in semi-infinite multi-objective fractional programming.

    Science.gov (United States)

    Verma, Ram U; Seol, Youngsoo

    2016-01-01

    First a new notion of the random exponential Hanson-Antczak type [Formula: see text]-V-invexity is introduced, which generalizes most of the existing notions in the literature, second a random function [Formula: see text] of the second order is defined, and finally a class of asymptotically sufficient efficiency conditions in semi-infinite multi-objective fractional programming is established. Furthermore, several sets of asymptotic sufficiency results in which various generalized exponential type [Formula: see text]-V-invexity assumptions are imposed on certain vector functions whose components are the individual as well as some combinations of the problem functions are examined and proved. To the best of our knowledge, all the established results on the semi-infinite aspects of the multi-objective fractional programming are new, which is a significantly new emerging field of the interdisciplinary research in nature. We also observed that the investigated results can be modified and applied to several special classes of nonlinear programming problems.

  3. Asymptotics and Borel summability

    CERN Document Server

    Costin, Ovidiu

    2008-01-01

    Incorporating substantial developments from the last thirty years into one resource, Asymptotics and Borel Summability provides a self-contained introduction to asymptotic analysis with special emphasis on topics not covered in traditional asymptotics books. The author explains basic ideas, concepts, and methods of generalized Borel summability, transseries, and exponential asymptotics. He provides complete mathematical rigor while supplementing it with heuristic material and examples, so that some proofs may be omitted by applications-oriented readers.To give a sense of how new methods are us

  4. First-passage time asymptotics over moving boundaries for random walk bridges

    NARCIS (Netherlands)

    Sloothaak, F.; Zwart, B.; Wachtel, V.

    2017-01-01

    We study the asymptotic tail probability of the first-passage time over a moving boundary for a random walk conditioned to return to zero, where the increments of the random walk have finite variance. Typically, the asymptotic tail behavior may be described through a regularly varying function with

  5. Asymptotic stability of a genetic network under impulsive control

    International Nuclear Information System (INIS)

    Li Fangfei; Sun Jitao

    2010-01-01

    The study of the stability of genetic network is an important motif for the understanding of the living organism at both molecular and cellular levels. In this Letter, we provide a theoretical method for analyzing the asymptotic stability of a genetic network under impulsive control. And the sufficient conditions of its asymptotic stability under impulsive control are obtained. Finally, an example is given to illustrate the effectiveness of the obtained method.

  6. A generalized L1-approach for a kernel estimator of conditional quantile with functional regressors: Consistency and asymptotic normality

    OpenAIRE

    2009-01-01

    Abstract A kernel estimator of the conditional quantile is defined for a scalar response variable given a covariate taking values in a semi-metric space. The approach generalizes the median?s L1-norm estimator. The almost complete consistency and asymptotic normality are stated. correspondance: Corresponding author. Tel: +33 320 964 933; fax: +33 320 964 704. (Lemdani, Mohamed) (Laksaci, Ali) mohamed.lemdani@univ-lill...

  7. Analysis of polarization in hydrogen bonded complexes: An asymptotic projection approach

    Science.gov (United States)

    Drici, Nedjoua

    2018-03-01

    The asymptotic projection technique is used to investigate the polarization effect that arises from the interaction between the relaxed, and frozen monomeric charge densities of a set of neutral and charged hydrogen bonded complexes. The AP technique based on the resolution of the original Kohn-Sham equations can give an acceptable qualitative description of the polarization effect in neutral complexes. The significant overlap of the electron densities, in charged and π-conjugated complexes, impose further development of a new functional, describing the coupling between constrained and non-constrained electron densities within the AP technique to provide an accurate representation of the polarization effect.

  8. Black hole thermodynamics from a variational principle: asymptotically conical backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    An, Ok Song [SISSA and INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy); Department of Physics, Kim Il Sung University,Ryongnam Dong, TaeSong District, Pyongyang, D.P.R. (Korea, Republic of); ICTP,Strada Costiera 11, 34014 Trieste (Italy); Cvetič, Mirjam [Department of Physics and Astronomy, University of Pennsylvania,209 S 33rd St, Philadelphia, PA 19104 (United States); Center for Applied Mathematics and Theoretical Physics, University of Maribor,Mladinska 3, SI2000 Maribor (Slovenia); Papadimitriou, Ioannis [SISSA and INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy)

    2016-03-14

    The variational problem of gravity theories is directly related to black hole thermodynamics. For asymptotically locally AdS backgrounds it is known that holographic renormalization results in a variational principle in terms of equivalence classes of boundary data under the local asymptotic symmetries of the theory, which automatically leads to finite conserved charges satisfying the first law of thermodynamics. We show that this connection holds well beyond asymptotically AdS black holes. In particular, we formulate the variational problem for N=2 STU supergravity in four dimensions with boundary conditions corresponding to those obeyed by the so called ‘subtracted geometries’. We show that such boundary conditions can be imposed covariantly in terms of a set of asymptotic second class constraints, and we derive the appropriate boundary terms that render the variational problem well posed in two different duality frames of the STU model. This allows us to define finite conserved charges associated with any asymptotic Killing vector and to demonstrate that these charges satisfy the Smarr formula and the first law of thermodynamics. Moreover, by uplifting the theory to five dimensions and then reducing on a 2-sphere, we provide a precise map between the thermodynamic observables of the subtracted geometries and those of the BTZ black hole. Surface terms play a crucial role in this identification.

  9. Asymptotically Safe Dark Matter

    DEFF Research Database (Denmark)

    Sannino, Francesco; Shoemaker, Ian M.

    2015-01-01

    We introduce a new paradigm for dark matter (DM) interactions in which the interaction strength is asymptotically safe. In models of this type, the coupling strength is small at low energies but increases at higher energies, and asymptotically approaches a finite constant value. The resulting...... searches are the primary ways to constrain or discover asymptotically safe dark matter....

  10. Asymptotic Eigenstructures

    Science.gov (United States)

    Thompson, P. M.; Stein, G.

    1980-01-01

    The behavior of the closed loop eigenstructure of a linear system with output feedback is analyzed as a single parameter multiplying the feedback gain is varied. An algorithm is presented that computes the asymptotically infinite eigenstructure, and it is shown how a system with high gain, feedback decouples into single input, single output systems. Then a synthesis algorithm is presented which uses full state feedback to achieve a desired asymptotic eigenstructure.

  11. Almost Surely Asymptotic Stability of Exact and Numerical Solutions for Neutral Stochastic Pantograph Equations

    Directory of Open Access Journals (Sweden)

    Zhanhua Yu

    2011-01-01

    Full Text Available We study the almost surely asymptotic stability of exact solutions to neutral stochastic pantograph equations (NSPEs, and sufficient conditions are obtained. Based on these sufficient conditions, we show that the backward Euler method (BEM with variable stepsize can preserve the almost surely asymptotic stability. Numerical examples are demonstrated for illustration.

  12. Extended asymptotic functions - some examples

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1981-01-01

    Several examples of extended asymptotic functions of two variables are given. This type of asymptotic functions has been introduced as an extension of continuous ordinary functions. The presented examples are realizations of some Schwartz distributions delta(x), THETA(x), P(1/xsup(n)) and can be multiplied in the class of the asymptotic functions as opposed to the theory of Schwartz distributions. The examples illustrate the method of construction of extended asymptotic functions similar to the distributions. The set formed by the extended asymptotic functions is also considered. It is shown, that this set is not closed with respect to addition and multiplication

  13. Dynamics and relaxation in confined medium. Application to 129Xe magnetic relaxation in Vycor

    International Nuclear Information System (INIS)

    Pasquier, Virginie

    1995-01-01

    Porous media morphology and topology drive the exploration of pore space by fluid. So, analysis of transport process, associated with relaxation mechanism, allows indirect study of pore geometry. The purpose of this work is to understand better the relation between geometry and transport. This study involves two parts: a modelization and prediction step is followed by an experimental application of magnetic relaxation. Numerical simulations and analytical models allow to quantify the influence on the solid interface of the dynamical behavior of confined gas in disordered porous media (granular structure and porous network) or in common geometry (cylindrical and lamellar interfaces). The formalism of diffusion propagator is a powerful tool to quantify the influence of the pore geometry on the diffusion of confined gas. The propagator holds all dynamical information on the system; it also predicts the temporal evolution of the autocorrelation functions of the Hamiltonian describing local coupling. In an intermediate time scale, magnetic relaxation shows complex diffusional regime: the autocorrelation functions decrease in a power law with a exponent smaller than d/2 (where d is the Euclidian dimension of the system). This behavior is analogous to dynamic in low-dimensional space, but here arises from surface correlations of the porous media. The long-time behavior of the autocorrelation functions retrieves the asymptotic decrease t -d/2 . Moreover, atypical behavior is observed for the Knudsen diffusion between infinite planes. It turns out that 129 Xe NMR is a appropriate technique to characterize organization and diffusion of gas confined in Vycor. Systematic studies of temperature and pressure effect on the 129 Xe chemical shift allow to specify the Xe/solid interaction. The analysis of the relaxation measurements, thanks to the numerical development, confirms conclusions arising from the study of diffusion propagator. (author) [fr

  14. Asymptotics of relativistic spin networks

    International Nuclear Information System (INIS)

    Barrett, John W; Steele, Christopher M

    2003-01-01

    The stationary phase technique is used to calculate asymptotic formulae for SO(4) relativistic spin networks. For the tetrahedral spin network this gives the square of the Ponzano-Regge asymptotic formula for the SU(2) 6j-symbol. For the 4-simplex (10j-symbol) the asymptotic formula is compared with numerical calculations of the spin network evaluation. Finally, we discuss the asymptotics of the SO(3, 1) 10j-symbol

  15. Residual stresses relaxation in surface-hardened half-space under creep conditions

    Directory of Open Access Journals (Sweden)

    Vladimir P. Radchenko

    2015-09-01

    Full Text Available We developed the method for solving the problem of residual stresses relaxation in surface-hardened layer of half-space under creep conditions. At the first stage we made the reconstruction of stress-strain state in half-space after plastic surface hardening procedure based on partial information about distribution for one residual stress tensor component experimentally detected. At the second stage using a numerical method we solve the problem of relaxation of self-balanced residual stresses under creep conditions. To solve this problem we introduce the following Cartesian system: x0y plane is aligned with hardened surface of half-space and 0z axis is directed to the depth of hardened layer. We also introduce the hypotheses of plane sections parallel to x0z and y0z planes. Detailed analysis of the problem has been done. Comparison of the calculated data with the corresponding test data was made for plane specimens (rectangular parallelepipeds made of EP742 alloy during T=650°C after the ultrasonic hardening with four hardening modes. We use half-space to model these specimens because penetration's depth of residual stresses is less than specimen general size in two digit exponent. There is enough correspondence of experimental and calculated data. It is shown that there is a decay (in modulus of pressing residual stresses under creep in 1.4–1.6 times.

  16. The drift-flux asymptotic limit of baro-tropic two-phase two-pressure models

    International Nuclear Information System (INIS)

    Ambroso, A.; Galie, Th.; Chalons, Ch.; Coquel, F.; Godlewski, E.; Raviart, P.A.; Seguin, N.; Coquel, F.

    2008-01-01

    We study the asymptotic behavior of the solutions of baro-tropic two-phase two-pressure models, with pressure relaxation, drag force and external forces. Using Chapman-Enskog expansions close to the expected equilibrium, a drift-flux model with a Darcy type closure law is obtained. Also, restricting this closure law to permanent flows (defined as steady flows in some Lagrangian frame), we can obtain a drift-flux model with an algebraic closure law, in the spirit of Zuber-Findlay models. The example of a two-phase flow in a vertical pipe is described. (authors)

  17. Asymptotic and geometrical quantization

    International Nuclear Information System (INIS)

    Karasev, M.V.; Maslov, V.P.

    1984-01-01

    The main ideas of geometric-, deformation- and asymptotic quantizations are compared. It is shown that, on the one hand, the asymptotic approach is a direct generalization of exact geometric quantization, on the other hand, it generates deformation in multiplication of symbols and Poisson brackets. Besides investigating the general quantization diagram, its applications to the calculation of asymptotics of a series of eigenvalues of operators possessing symmetry groups are considered

  18. Asymptotically Optimal Agents

    OpenAIRE

    Lattimore, Tor; Hutter, Marcus

    2011-01-01

    Artificial general intelligence aims to create agents capable of learning to solve arbitrary interesting problems. We define two versions of asymptotic optimality and prove that no agent can satisfy the strong version while in some cases, depending on discounting, there does exist a non-computable weak asymptotically optimal agent.

  19. Comparison and extension of a direct model reference adaptive control procedure

    Science.gov (United States)

    Neat, Gregory W.; Kaufman, Howard; Steinvorth, Rodrigo

    1992-01-01

    This paper analyzes and extends an easily implemented direct model reference adaptive control procedure. The paper focuses on the major limitation of this control approach which is the satisfaction of a strictly positive real sufficiency condition in order to guarantee asymptotic tracking. Attempts, to date, to address this problem have been unable to relax simultaneously the stringent condition and maintain asymptotic tracking capabilities. Three different modifications to existing versions of this algorithm are presented which substantially relax the stringent sufficiency condition while providing asymptotic tracking. These three modifications achieve this goal by imposing slight adjustments to existing sufficiency conditions. A simulation example demonstrates that the modifications eliminate the steady error inherent in the existing methods.

  20. Asymptotically Safe Standard Model via Vectorlike Fermions

    Science.gov (United States)

    Mann, R. B.; Meffe, J. R.; Sannino, F.; Steele, T. G.; Wang, Z. W.; Zhang, C.

    2017-12-01

    We construct asymptotically safe extensions of the standard model by adding gauged vectorlike fermions. Using large number-of-flavor techniques we argue that all gauge couplings, including the hypercharge and, under certain conditions, the Higgs coupling, can achieve an interacting ultraviolet fixed point.

  1. Variationally Asymptotically Stable Difference Systems

    Directory of Open Access Journals (Sweden)

    Goo YoonHoe

    2007-01-01

    Full Text Available We characterize the h-stability in variation and asymptotic equilibrium in variation for nonlinear difference systems via n∞-summable similarity and comparison principle. Furthermore we study the asymptotic equivalence between nonlinear difference systems and their variational difference systems by means of asymptotic equilibria of two systems.

  2. Asymptotics of the Eigenvalues of a Self-Adjoint Fourth Order Boundary Value Problem with Four Eigenvalue Parameter Dependent Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Manfred Möller

    2013-01-01

    Full Text Available Considered is a regular fourth order ordinary differential equation which depends quadratically on the eigenvalue parameter λ and which has separable boundary conditions depending linearly on λ. It is shown that the eigenvalues lie in the closed upper half plane or on the imaginary axis and are symmetric with respect to the imaginary axis. The first four terms in the asymptotic expansion of the eigenvalues are provided.

  3. Polynomial Asymptotes of the Second Kind

    Science.gov (United States)

    Dobbs, David E.

    2011-01-01

    This note uses the analytic notion of asymptotic functions to study when a function is asymptotic to a polynomial function. Along with associated existence and uniqueness results, this kind of asymptotic behaviour is related to the type of asymptote that was recently defined in a more geometric way. Applications are given to rational functions and…

  4. Macro-mesoscopic Fracture and Strength Character of Pre-cracked Granite Under Stress Relaxation Condition

    Science.gov (United States)

    Liu, Junfeng; Yang, Haiqing; Xiao, Yang; Zhou, Xiaoping

    2018-05-01

    The fracture characters are important index to study the strength and deformation behavior of rock mass in rock engineering. In order to investigate the influencing mechanism of loading conditions on the strength and macro-mesoscopic fracture character of rock material, pre-cracked granite specimens are prepared to conduct a series of uniaxial compression experiments. For parts of the experiments, stress relaxation tests of different durations are also conducted during the uniaxial loading process. Furthermore, the stereomicroscope is adopted to observe the microstructure of the crack surfaces of the specimens. The experimental results indicate that the crack surfaces show several typical fracture characters in accordance with loading conditions. In detail, some cleavage fracture can be observed under conventional uniaxial compression and the fractured surface is relatively rough, whereas as stress relaxation tests are attached, relative slip trace appears between the crack faces and some shear fracture starts to come into being. Besides, the crack faces tend to become smoother and typical terrace structures can be observed in local areas. Combining the macroscopic failure pattern of the specimens, it can be deduced that the duration time for the stress relaxation test contributes to the improvement of the elastic-plastic strain range as well as the axial peak strength for the studied material. Moreover, the derived conclusion is also consistent with the experimental and analytical solution for the pre-peak stage of the rock material. The present work may provide some primary understanding about the strength character and fracture mechanism of hard rock under different engineering environments.

  5. Relaxation of vacuum energy in q-theory

    Science.gov (United States)

    Klinkhamer, F. R.; Savelainen, M.; Volovik, G. E.

    2017-08-01

    The q-theory formalism aims to describe the thermodynamics and dynamics of the deep quantum vacuum. The thermodynamics leads to an exact cancellation of the quantum-field zero-point-energies in equilibrium, which partly solves the main cosmological constant problem. But, with reversible dynamics, the spatially flat Friedmann-Robertson-Walker universe asymptotically approaches the Minkowski vacuum only if the Big Bang already started out in an initial equilibrium state. Here, we extend q-theory by introducing dissipation from irreversible processes. Neglecting the possible instability of a de-Sitter vacuum, we obtain different scenarios with either a de-Sitter asymptote or collapse to a final singularity. The Minkowski asymptote still requires fine-tuning of the initial conditions. This suggests that, within the q-theory approach, the decay of the de-Sitter vacuum is a necessary condition for the dynamical solution of the cosmological constant problem.

  6. Real-time relaxation and kinetics in hot scalar QED: Landau damping

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de; Holman, R.; Kumar, S.P.; Pisarski, R.D.

    1998-01-01

    The real time evolution of non-equilibrium expectation values with soft length scales ∼k -1 >(eT) -1 is solved in hot scalar electrodynamics, with a view towards understanding relaxational phenomena in the QGP and the electroweak plasma. We find that the gauge invariant non-equilibrium expectation values relax via power laws to asymptotic amplitudes that are determined by the quasiparticle poles. The long time relaxational dynamics and relevant time scales are determined by the behavior of the retarded self-energy not at the small frequencies, but at the Landau damping thresholds. This explains the presence of power laws and not of exponential decay. In the process we rederive the HTL effective action using non-equilibrium field theory. Furthermore we obtain the influence functional, the Langevin equation and the fluctuation-dissipation theorem for the soft modes, identifying the correlators that emerge in the classical limit. We show that a Markovian approximation fails to describe the dynamics both at short and long times. We find that the distribution function for soft quasiparticles relaxes with a power law through Landau damping. We also introduce a novel kinetic approach that goes beyond the standard Boltzmann equation by incorporating off-shell processes and find that the distribution function for soft quasiparticles relaxes with a power law through Landau damping. We find an unusual dressing dynamics of bare particles and anomalous (logarithmic) relaxation of hard quasiparticles. copyright 1998 The American Physical Society

  7. Asymptotic numbers: Pt.1

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1980-01-01

    The set of asymptotic numbers A as a system of generalized numbers including the system of real numbers R, as well as infinitely small (infinitesimals) and infinitely large numbers, is introduced. The detailed algebraic properties of A, which are unusual as compared with the known algebraic structures, are studied. It is proved that the set of asymptotic numbers A cannot be isomorphically embedded as a subspace in any group, ring or field, but some particular subsets of asymptotic numbers are shown to be groups, rings, and fields. The algebraic operation, additive and multiplicative forms, and the algebraic properties are constructed in an appropriate way. It is shown that the asymptotic numbers give rise to a new type of generalized functions quite analogous to the distributions of Schwartz allowing, however, the operation multiplication. A possible application of these functions to quantum theory is discussed

  8. On the asymptotic stability of nonlinear mechanical switched systems

    Science.gov (United States)

    Platonov, A. V.

    2018-05-01

    Some classes of switched mechanical systems with dissipative and potential forces are considered. The case, where either dissipative or potential forces are essentially nonlinear, is studied. It is assumed that the zero equilibrium position of the system is asymptotically stable at least for one operating mode. We will look for sufficient conditions which guarantee the preservation of asymptotic stability of the equilibrium position under the switching of modes. The Lyapunov direct method is used. A Lyapunov function for considered system is constructed, which satisfies the differential inequality of special form for every operating mode. This inequality is nonlinear for the chosen mode with asymptotically stable equilibrium position, and it is linear for the rest modes. The correlations between the intervals of activity of the pointed mode and the intervals of activity of the rest modes are obtained which guarantee the required properties.

  9. Asymptotic Safety Guaranteed in Supersymmetry

    Science.gov (United States)

    Bond, Andrew D.; Litim, Daniel F.

    2017-11-01

    We explain how asymptotic safety arises in four-dimensional supersymmetric gauge theories. We provide asymptotically safe supersymmetric gauge theories together with their superconformal fixed points, R charges, phase diagrams, and UV-IR connecting trajectories. Strict perturbative control is achieved in a Veneziano limit. Consistency with unitarity and the a theorem is established. We find that supersymmetry enhances the predictivity of asymptotically safe theories.

  10. On the asymptotics of the Gell-Mann-Low function in quantum field theory

    International Nuclear Information System (INIS)

    Kazakov, D.I.; Popov, V.S.

    2003-01-01

    The problem of reconstructing the Gell-Mann-Low function in quantum field theory starting with its asymptotic series with the first terms calculated by perturbation theory is discussed. And though in a strict mathematical sense this is not unambiguously realizable, under reasonable assumptions about the function it appears to be possible to reconstruct it in some finite interval of g. However, any attempts to find its asymptotics as g→∞ from our point of view are not justified. We also present the conditions under which the sum of the asymptotic series may decrease at infinity

  11. Asymptotically flat structure of hypergravity in three spacetime dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Fuentealba, Oscar [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción,Casilla 160-C, Concepción (Chile); Matulich, Javier; Troncoso, Ricardo [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile)

    2015-10-02

    The asymptotic structure of three-dimensional hypergravity without cosmological constant is analyzed. In the case of gravity minimally coupled to a spin-5/2 field, a consistent set of boundary conditions is proposed, being wide enough so as to accommodate a generic choice of chemical potentials associated to the global charges. The algebra of the canonical generators of the asymptotic symmetries is given by a hypersymmetric nonlinear extension of BMS{sub 3}. It is shown that the asymptotic symmetry algebra can be recovered from a subset of a suitable limit of the direct sum of the W{sub (2,4)} algebra with its hypersymmetric extension. The presence of hypersymmetry generators allows to construct bounds for the energy, which turn out to be nonlinear and saturate for spacetimes that admit globally-defined “Killing vector-spinors”. The null orbifold or Minkowski spacetime can then be seen as the corresponding ground state in the case of fermions that fulfill periodic or antiperiodic boundary conditions, respectively. The hypergravity theory is also explicitly extended so as to admit parity-odd terms in the action. It is then shown that the asymptotic symmetry algebra includes an additional central charge, being proportional to the coupling of the Lorentz-Chern-Simons form. The generalization of these results in the case of gravity minimally coupled to arbitrary half-integer spin fields is also carried out. The hypersymmetry bounds are found to be given by a suitable polynomial of degree s+(1/2) in the energy, where s is the spin of the fermionic generators.

  12. An asymptotic solution of large-N QCD

    Directory of Open Access Journals (Sweden)

    Bochicchio Marco

    2014-01-01

    Full Text Available We find an asymptotic solution for two-, three- and multi-point correlators of local gauge-invariant operators, in a lower-spin sector of massless large-N QCD, in terms of glueball and meson propagators, in such a way that the solution is asymptotic in the ultraviolet to renormalization-group improved perturbation theory, by means of a new purely field-theoretical technique that we call the asymptotically-free bootstrap, based on a recently-proved asymptotic structure theorem for two-point correlators. The asymptotically-free bootstrap provides as well asymptotic S-matrix amplitudes in terms of glueball and meson propagators. Remarkably, the asymptotic S-matrix depends only on the unknown particle spectrum, but not on the anomalous dimensions, as a consequence of the LS Z reduction formulae. Very many physics consequences follow, both practically and theoretically. In fact, the asymptotic solution sets the strongest constraints on any actual solution of large-N QCD, and in particular on any string solution.

  13. Evaluating the influence of initial magnetization conditions on extracted exchange parameters in NMR relaxation experiments: applications to CPMG and CEST

    Energy Technology Data Exchange (ETDEWEB)

    Yuwen, Tairan; Sekhar, Ashok; Kay, Lewis E., E-mail: kay@pound.med.utoronto.ca [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada)

    2016-08-15

    Transient excursions of native protein states to functionally relevant higher energy conformations often occur on the μs–ms timescale. NMR spectroscopy has emerged as an important tool to probe such processes using techniques such as Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion and Chemical Exchange Saturation Transfer (CEST). The extraction of kinetic and structural parameters from these measurements is predicated upon mathematical modeling of the resulting relaxation profiles, which in turn relies on knowledge of the initial magnetization conditions at the start of the CPMG/CEST relaxation elements in these experiments. Most fitting programs simply assume initial magnetization conditions that are given by equilibrium populations, which may be incorrect in certain implementations of experiments. In this study we have quantified the systematic errors in extracted parameters that are generated from analyses of CPMG and CEST experiments using incorrect initial boundary conditions. We find that the errors in exchange rates (k{sub ex}) and populations (p{sub E}) are typically small (<10 %) and thus can be safely ignored in most cases. However, errors become larger and cannot be fully neglected (20–40 %) as k{sub ex} falls near the lower limit of each method or when short CPMG/CEST relaxation elements are used in these experiments. The source of the errors can be rationalized and their magnitude given by a simple functional form. Despite the fact that errors tend to be small, it is recommended that the correct boundary conditions be implemented in fitting programs so as to obtain as robust estimates of exchange parameters as possible.

  14. Global asymptotic stability of Cohen-Grossberg neural networks with constant and variable delays

    International Nuclear Information System (INIS)

    Wu Wei; Cui Baotong; Huang Min

    2007-01-01

    Global asymptotic stability of Cohen-Grossberg neural networks with constant and variable delays is studied. Some sufficient conditions for the neural networks are proposed to guarantee the global asymptotic convergence by using different Lyapunov functionals. Our criteria represent an extension of the existing results in literatures. A comparison between our results and the previous results admits that our results establish a new set of stability criteria for delayed Cohen-Grossberg neural networks. Those conditions are less restrictive than those given in the earlier reference

  15. Asymptotic stability of discrete-time systems with time-varying delay subject to saturation nonlinearities

    International Nuclear Information System (INIS)

    Chen, S.-F.

    2009-01-01

    The asymptotic stability problem for discrete-time systems with time-varying delay subject to saturation nonlinearities is addressed in this paper. In terms of linear matrix inequalities (LMIs), a delay-dependent sufficient condition is derived to ensure the asymptotic stability. A numerical example is given to demonstrate the theoretical results.

  16. Generating asymptotically plane wave spacetimes

    International Nuclear Information System (INIS)

    Hubeny, Veronika E.; Rangamani, Mukund

    2003-01-01

    In an attempt to study asymptotically plane wave spacetimes which admit an event horizon, we find solutions to vacuum Einstein's equations in arbitrary dimension which have a globally null Killing field and rotational symmetry. We show that while such solutions can be deformed to include ones which are asymptotically plane wave, they do not posses a regular event horizon. If we allow for additional matter, such as in supergravity theories, we show that it is possible to have extremal solutions with globally null Killing field, a regular horizon, and which, in addition, are asymptotically plane wave. In particular, we deform the extremal M2-brane solution in 11-dimensional supergravity so that it behaves asymptotically as a 10-dimensional vacuum plane wave times a real line. (author)

  17. Asymptotic twistor theory and the Kerr theorem

    International Nuclear Information System (INIS)

    Newman, Ezra T

    2006-01-01

    We first review asymptotic twistor theory with its real subspace of null asymptotic twistors: a five-dimensional CR manifold. This is followed by a description of the Kerr theorem (the identification of shear-free null congruences, in Minkowski space, with the zeros of holomorphic functions of three variables) and an asymptotic version of the Kerr theorem that produces regular asymptotically shear-free null geodesic congruences in arbitrary asymptotically flat Einstein or Einstein-Maxwell spacetimes. A surprising aspect of this work is the role played by analytic curves in H-space, each curve generating an asymptotically flat null geodesic congruence. Also there is a discussion of the physical space realizations of the two associated five- and three-dimensional CR manifolds

  18. Tail asymptotics for dependent subexponential differences

    DEFF Research Database (Denmark)

    Albrecher, H; Asmussen, Søren; Kortschak, D.

    We study the asymptotic behavior of P(X − Y > u) as u → ∞, where X is subexponential and X, Y are positive random variables that may be dependent. We give criteria under which the subtraction of Y does not change the tail behavior of X. It is also studied under which conditions the comonotonic co...

  19. Asymptotic integration of differential and difference equations

    CERN Document Server

    Bodine, Sigrun

    2015-01-01

    This book presents the theory of asymptotic integration for both linear differential and difference equations. This type of asymptotic analysis is based on some fundamental principles by Norman Levinson. While he applied them to a special class of differential equations, subsequent work has shown that the same principles lead to asymptotic results for much wider classes of differential and also difference equations. After discussing asymptotic integration in a unified approach, this book studies how the application of these methods provides several new insights and frequent improvements to results found in earlier literature. It then continues with a brief introduction to the relatively new field of asymptotic integration for dynamic equations on time scales. Asymptotic Integration of Differential and Difference Equations is a self-contained and clearly structured presentation of some of the most important results in asymptotic integration and the techniques used in this field. It will appeal to researchers i...

  20. A note on asymptotic expansions for Markov chains using operator theory

    DEFF Research Database (Denmark)

    Jensen, J.L.

    1987-01-01

    We consider asymptotic expansions for sums Sn on the form Sn = fhook0(X0) + fhook(X1, X0) + ... + fhook(Xn, Xn-1), where Xi is a Markov chain. Under different ergodicity conditions on the Markov chain and certain conditional moment conditions on fhook(Xi, Xi-1), a simple representation...

  1. Asymptotic behaviour of Feynman integrals

    International Nuclear Information System (INIS)

    Bergere, M.C.

    1980-01-01

    In these lecture notes, we describe how to obtain the asymptotic behaviour of Feynman amplitudes; this technique has been already applied in several cases, but the general solution for any kind of asymptotic behaviour has not yet been found. From the mathematical point of view, the problem to solve is close to the following problem: find the asymptotic expansion at large lambda of the integral ∫...∫ [dx] esup(-LambdaP[x]) where P[x] is a polynomial of several variables. (orig.)

  2. Asymptotics of a Steady-State Condition of Finite-Difference Approximation of a Logistic Equation with Delay and Small Diffusion

    Directory of Open Access Journals (Sweden)

    S. A. Kaschenko

    2014-01-01

    Full Text Available We study the dynamics of finite-difference approximation on spatial variables of a logistic equation with delay and diffusion. It is assumed that the diffusion coefficient is small and the Malthusian coefficient is large. The question of the existence and asymptotic behavior of attractors was studied with special asymptotic methods. It is shown that there is a rich array of different types of attractors in the phase space: leading centers, spiral waves, etc. The main asymptotic characteristics of all solutions from the corresponding attractors are adduced in this work. Typical graphics of wave fronts motion of different structures are represented in the article.

  3. Nonminimal hints for asymptotic safety

    Science.gov (United States)

    Eichhorn, Astrid; Lippoldt, Stefan; Skrinjar, Vedran

    2018-01-01

    In the asymptotic-safety scenario for gravity, nonzero interactions are present in the ultraviolet. This property should also percolate into the matter sector. Symmetry-based arguments suggest that nonminimal derivative interactions of scalars with curvature tensors should therefore be present in the ultraviolet regime. We perform a nonminimal test of the viability of the asymptotic-safety scenario by working in a truncation of the renormalization group flow, where we discover the existence of an interacting fixed point for a corresponding nonminimal coupling. The back-coupling of such nonminimal interactions could in turn destroy the asymptotically safe fixed point in the gravity sector. As a key finding, we observe nontrivial indications of stability of the fixed-point properties under the impact of nonminimal derivative interactions, further strengthening the case for asymptotic safety in gravity-matter systems.

  4. Effect of interaction range on phonon relaxation in Fermi-Pasta-Ulam beta chain.

    Science.gov (United States)

    Santhosh, G; Kumar, Deepak

    2007-08-01

    We study the effect of increasing the range of interactions on phonon relaxation in a chain of atoms with quartic anharmonicity. The study is motivated by recent numerical studies, showing that the value of the exponent alpha characterizing the divergence of conductivity with system size apparently depends on the presence of second neighbor couplings. We perform a quantum calculation of the wave-vector (q) dependent relaxation rate gamma(q) in the second order perturbation theory. The nonanalytic dependence of gamma(q) arises due to small-q singularity of the collision integral. We find that gamma(q) proportional to Aq(5/3) + Bq2. This gives rise to an asymptotic value alpha = 0.4, but the q2 terms lead to a higher apparent value of alpha at small sizes of the chain.

  5. Asymptotic functions and multiplication of distributions

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1979-01-01

    Considered is a new type of generalized asymptotic functions, which are not functionals on some space of test functions as the Schwartz distributions. The definition of the generalized asymptotic functions is given. It is pointed out that in future the particular asymptotic functions will be used for solving some topics of quantum mechanics and quantum theory

  6. Impact of growth and annealing conditions on the parameters of Ge/Si(001) relaxed layers grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Yurasov, D. V., E-mail: Inquisitor@ipm.sci-nnov.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Bobrov, A. I. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Daniltsev, V. M.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Pavlov, D. A. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Skorokhodov, E. V.; Shaleev, M. V.; Yunin, P. A. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2015-11-15

    Influence of the Ge layer thickness and annealing conditions on the parameters of relaxed Ge/Si(001) layers grown by molecular beam epitaxy via two-stage growth is investigated. The dependences of the threading dislocation density and surface roughness on the Ge layer thickness, annealing temperature and time, and the presence of a hydrogen atmosphere are obtained. As a result of optimization of the growth and annealing conditions, relaxed Ge/Si(001) layers which are thinner than 1 μm with a low threading dislocation density on the order of 10{sup 7} cm{sup –2} and a root mean square roughness of less than 1 nm are obtained.

  7. Influence of the storage conditions on prestressing steel relaxation losses

    Directory of Open Access Journals (Sweden)

    Suárez, F.

    2012-12-01

    Full Text Available Stress relaxation losses on active reinforcement have significant impact on prestressed concrete structures. This is why relaxation tests are carried out on prestressing steel wires and strands after being manufactured. Then, these materials are coiled and stored for a long-term period, sometimes in excess of one year. The influence of these operations, carried out after manufacturing, is usually neglected. Nevertheless, some manufacturers and contractors have noticed that, sometimes, when relaxation tests are carried out after a long-term storage, the relaxation losses found are higher than those measured immediately after manufacturing. In this work, lab tests are performed to check the influence of the coiling radius and the period of storage on the relaxation test. In addition to this, an analytical model is presented to predict the results of a relaxation test carried out on a wire coiled and stored for a long-term period. This model explains the evolution on the cross-sectional stress profile along the coiling-storing-uncoiling process, as well as the influence of the residual stresses on it.

    La pérdida de tensión por relajación en las armaduras activas afecta de forma importante a las estructuras de hormigón pretensado. Por ello se realizan ensayos de relajación de los alambres y cordones de pretensado tras su fabricación. Después, el material es enrollado y almacenado durante periodos que en ocasiones pueden superar el año de duración. Generalmente se desprecia la influencia que estas operaciones posteriores a la fabricación pueden tener sobre el material. Sin embargo, diversos fabricantes y suministradores han constatado experimentalmente que, en ocasiones, el material almacenado durante un periodo prolongado presenta pérdidas de relajación mayores que inmediatamente tras su fabricación. En este trabajo se realizan ensayos de laboratorio para comprobar la influencia que el radio de enrollamiento y el periodo de

  8. Properties of the relaxation time distribution underlying the Kohlrausch-Williams-Watts photoionization of the DX centers in Cd1-xMnxTe mixed crystals

    International Nuclear Information System (INIS)

    Trzmiel, J; Weron, K; Placzek-Popko, E; Janczura, J

    2009-01-01

    In this paper we clarify the relationship between the relaxation rate and relaxation time distributions underlying the Kohlrausch-Williams-Watts (KWW) photoconductivity build-ups in indium- and gallium-doped Cd 1-x Mn x Te mixed crystals. We discuss the role of asymptotic properties of the corresponding probability density functions. We show that the relaxation rate distribution, as a completely asymmetric α-stable distribution, leads to an infinite mean value of the effective relaxation rate. In contrast, the relaxation time distribution related to it leads to a finite mean value of the effective relaxation time. It follows from the experimental data analysis that for all the investigated samples the KWW exponent α decreases linearly with increasing photon flux in the range of (0.6-0.99) and its values are more spread in the case of gallium-doped material. We also observe a linear dependence of the mean relaxation time on the characteristic material time constant, which is consistent with the theoretical model.

  9. Asymptotically perfect discrimination in the local-operation-and-classical-communication paradigm

    International Nuclear Information System (INIS)

    Kleinmann, M.; Kampermann, H.; Bruss, D.

    2011-01-01

    We revisit the problem of discriminating orthogonal quantum states within the local-quantum-operation-and-classical-communication (LOCC) paradigm. Our particular focus is on the asymptotic situation where the parties have infinite resources and the protocol may become arbitrarily long. Our main result is a necessary condition for perfect asymptotic LOCC discrimination. As an application, we prove that for complete product bases, unlimited resources are of no advantage. On the other hand, we identify an example for which it still remains undecided whether unlimited resources are superior.

  10. First-passage time asymptotics over moving boundaries for random walk bridges

    OpenAIRE

    Sloothaak, F.; Zwart, B.; Wachtel, V.

    2017-01-01

    We study the asymptotic tail probability of the first-passage time over a moving boundary for a random walk conditioned to return to zero, where the increments of the random walk have finite variance. Typically, the asymptotic tail behavior may be described through a regularly varying function with exponent -1/2, where the impact of the boundary is captured by the slowly varying function. Yet, the moving boundary may have a stronger effect when the tail is considered at a time close to the re...

  11. Asymptotics of the QMLE for General ARCH(q) Models

    DEFF Research Database (Denmark)

    Kristensen, Dennis; Rahbek, Anders Christian

    2009-01-01

    -ARCH -- are derived. Strong consistency is established under the assumptions that the ARCH process is geometrically ergodic, the conditional variance function has a finite log-moment, and finite second moment of the rescaled error. Asymptotic normality of the estimator is established under the additional assumption...

  12. Existence and Asymptotic Stability of Periodic Solutions of the Reaction-Diffusion Equations in the Case of a Rapid Reaction

    Science.gov (United States)

    Nefedov, N. N.; Nikulin, E. I.

    2018-01-01

    A singularly perturbed periodic in time problem for a parabolic reaction-diffusion equation in a two-dimensional domain is studied. The case of existence of an internal transition layer under the conditions of balanced and unbalanced rapid reaction is considered. An asymptotic expansion of a solution is constructed. To justify the asymptotic expansion thus constructed, the asymptotic method of differential inequalities is used. The Lyapunov asymptotic stability of a periodic solution is investigated.

  13. Asymptotic and numerical studies of a differential-delay system

    Science.gov (United States)

    Semak, Matthew Richard

    A singularly-perturbed differential-delay equation is studied the form of which is seen in various fields. Relaxation effects are combined with nonlinear driving from the past in this system. Having an infinite dimensional phase space, this flow is capable of very interesting behavior. Among the rich aspects of the dynamics of such a relation, period doubling can be observed as parameters are varied. Rigorous proofs concerning the existence of such periodic solutions can be found in the literature. Attention is given to the (first) Hopf bifurcation as the periodic structure is born. Key questions concern the limit of fast relaxation. In this limit, one can analytically understand the development of the periodic solution in the neighborhood of the bifurcation along with the frequency shift which is encountered. This limit also reveals the underlying mapping structure present. In the model studied, this is the logistic map the behavior of which is well-known. Convergence of periodic solutions to the mapping's square wave involves central issues in this work. An analogue to Gibb's phenomenon presents itself as the mapping structure is approached for a certain range of parameters. Transition layers also exist and, together with the latter, present a challenge to various computational approaches. A highly accurate and efficient spectral numerical technique is introduced to properly resolve such behavior in the limit studied. This scheme is used to measure the period's dependence on the relaxation rate in this region of parameter space. Also, numerically assisted asymptotic analysis develops relations for the layers. Moreover, regimes of parameter values have been identified for which there exist extremely long-lived transient states of arbitrarily complex form. Finally, initial interval states are designed which lead to specific long-lived multi-layer patterns of significant complexity. Layer-layer interactions are considered concerning the formation and lifetime of

  14. Comparison between various notions of conserved charges in asymptotically AdS spacetimes

    International Nuclear Information System (INIS)

    Hollands, Stefan; Ishibashi, Akihiro; Marolf, Donald

    2005-01-01

    We derive Hamiltonian generators of asymptotic symmetries for general relativity with asymptotic AdS boundary conditions using the 'covariant phase space' method of Wald et al. We then compare our results with other definitions that have been proposed in the literature. We find that our definition agrees with that proposed by Ashtekar et al, with the spinor definition, and with the background-dependent definition of Henneaux and Teitelboim. Our definition disagrees with that obtained from the 'counterterm subtraction method', but the difference is found to consist only of a 'constant offset' that is determined entirely in terms of the boundary metric. We finally discuss and justify our boundary conditions by a linear perturbation analysis, and we comment on generalizations of our boundary conditions, as well as inclusion of matter fields

  15. Self-consistent field theory of collisions: Orbital equations with asymptotic sources and self-averaged potentials

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Y.K., E-mail: ykhahn22@verizon.net

    2014-12-15

    The self-consistent field theory of collisions is formulated, incorporating the unique dynamics generated by the self-averaged potentials. The bound state Hartree–Fock approach is extended for the first time to scattering states, by properly resolving the principal difficulties of non-integrable continuum orbitals and imposing complex asymptotic conditions. The recently developed asymptotic source theory provides the natural theoretical basis, as the asymptotic conditions are completely transferred to the source terms and the new scattering function is made fullyintegrable. The scattering solutions can then be directly expressed in terms of bound state HF configurations, establishing the relationship between the bound and scattering state solutions. Alternatively, the integrable spin orbitals are generated by constructing the individual orbital equations that contain asymptotic sources and self-averaged potentials. However, the orbital energies are not determined by the equations, and a special channel energy fixing procedure is developed to secure the solutions. It is also shown that the variational construction of the orbital equations has intrinsic ambiguities that are generally associated with the self-consistent approach. On the other hand, when a small subset of open channels is included in the source term, the solutions are only partiallyintegrable, but the individual open channels can then be treated more simply by properly selecting the orbital energies. The configuration mixing and channel coupling are then necessary to complete the solution. The new theory improves the earlier continuum HF model. - Highlights: • First extension of HF to scattering states, with proper asymptotic conditions. • Orbital equations with asymptotic sources and integrable orbital solutions. • Construction of self-averaged potentials, and orbital energy fixing. • Channel coupling and configuration mixing, involving the new orbitals. • Critical evaluation of the

  16. Distributed adaptive asymptotically consensus tracking control of uncertain Euler-Lagrange systems under directed graph condition.

    Science.gov (United States)

    Wang, Wei; Wen, Changyun; Huang, Jiangshuai; Fan, Huijin

    2017-11-01

    In this paper, a backstepping based distributed adaptive control scheme is proposed for multiple uncertain Euler-Lagrange systems under directed graph condition. The common desired trajectory is allowed totally unknown by part of the subsystems and the linearly parameterized trajectory model assumed in currently available results is no longer needed. To compensate the effects due to unknown trajectory information, a smooth function of consensus errors and certain positive integrable functions are introduced in designing virtual control inputs. Besides, to overcome the difficulty of completely counteracting the coupling terms of distributed consensus errors and parameter estimation errors in the presence of asymmetric Laplacian matrix, extra information transmission of local parameter estimates are introduced among linked subsystem and adaptive gain technique is adopted to generate distributed torque inputs. It is shown that with the proposed distributed adaptive control scheme, global uniform boundedness of all the closed-loop signals and asymptotically output consensus tracking can be achieved. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Nonlinear adaptive control system design with asymptotically stable parameter estimation error

    Science.gov (United States)

    Mishkov, Rumen; Darmonski, Stanislav

    2018-01-01

    The paper presents a new general method for nonlinear adaptive system design with asymptotic stability of the parameter estimation error. The advantages of the approach include asymptotic unknown parameter estimation without persistent excitation and capability to directly control the estimates transient response time. The method proposed modifies the basic parameter estimation dynamics designed via a known nonlinear adaptive control approach. The modification is based on the generalised prediction error, a priori constraints with a hierarchical parameter projection algorithm, and the stable data accumulation concepts. The data accumulation principle is the main tool for achieving asymptotic unknown parameter estimation. It relies on the parametric identifiability system property introduced. Necessary and sufficient conditions for exponential stability of the data accumulation dynamics are derived. The approach is applied in a nonlinear adaptive speed tracking vector control of a three-phase induction motor.

  18. Short-time Asymptotics of the Heat Kernel on Bounded Domain with Piecewise Smooth Boundary Conditions and Its Applications to an Ideal Gas

    Institute of Scientific and Technical Information of China (English)

    E.M.E. ZAYED

    2004-01-01

    The asymptotic expansion of the heat kernel Θ(t)(∞∑=(i=0))exp (-λi) where({λi}∞i=1) Are the eigen-values of negative Laplacian( -△n=-n∑k=1(θ/θxk)2)in Rn(n=2 or 3) is studied for short-time t for a general bounded domainθΩwith a smooth boundary θΩ.In this paper, we consider the case of a finite number of the Dirichlet conditions φ=0 on Γi (i = J +1,….,J)and the Neumann conditions and (θφ/θ vi) = 0 on Γi (i = J+1,…,k) and the Robin condition (θφ/θ vi+γi) θ=(I=k+1,… m) where γi are piecewise smooth positive impedancem(θφ=mUi=1Γi. )We construct the required asymptotics in the form of a power series over t. The senior coe.cients inthis series are speci.ed as functionals of the geometric shape of the domain Ω.This result is applied to calculatethe one-particle partition function of a "special ideal gas", i.e., the set of non-interacting particles set up in abox with Dirichlet, Neumann and Robin boundary conditions for the appropriate wave function. Calculationof the thermodynamic quantities for the ideal gas such as the internal energy, pressure and speci.c heat revealsthat these quantities alone are incapable of distinguishing between two di.erent shapes of the domain. Thisconclusion seems to be intuitively clear because it is based on a limited information given by a one-particlepartition function; nevertheless, its formal theoretical motivation is of some interest.

  19. Chiral symmetry breaking in asymptotically free and non-asymptotically free gauge theories

    International Nuclear Information System (INIS)

    Gusynin, V.P.; Miranskij, V.A.

    1986-01-01

    An essential distinction in the realization of the PCAC-dynamics in vector-like asymptotically free and non-asymptotically free (with a non-trival ultraviolet stable fixed point) gauge theories is revealed. For the latter theories an analytical expression for the condensate is obtained in the two-loop approximation and the arguments in support of a soft behaviour at small distances of composite operators are given. The problem of factorizing the low-energy region for the Wess-Zumino-Witten action is discussed

  20. The Kondo problem. II. Crossover from asymptotic freedom to infrared slavery

    Science.gov (United States)

    Schlottmann, P.

    1982-04-01

    In the preceding paper we transformed the s-d Hamiltonian onto a resonance level with a large perturbation and derived the scaling equations for the vertices, the invariant coupling, and the resonance width. The scaling equations are integrated under the assumption that the energy dependence of the resonance width can be neglected. The transcendental equation obtained in this way for the renormalized resonance width is solved in the relevant limits and allows a calculation of the static and dynamical susceptibility. At high temperatures the perturbation expansion for the relaxation rate and the susceptibility is reproduced up to third order in Jρ. At low temperatures the lifetime and χ0 remain finite and vary according to a Fermi-liquid theory. The approximation scheme interpolates in this way between the asymptotic freedom and the infrared slavery, yielding a smooth crossover. The present results are in quantitative agreement with previous ones obtained with the relaxation-kernel method by Götze and Schlottmann. The advantages and drawbacks of the method are discussed. The calculation of the dynamical susceptibility is extended to nonzero external magnetic fields. The quasielastic peak of χ''(ω)ω is suppressed at low temperatures and large magnetic fields and shoulders develop at ω=+/-B.

  1. Effect of the growth conditions on the anisotropy, domain structures and the relaxation in Co thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, Srijani; Mallick, Sougata; Bedanta, Subhankar, E-mail: sbedanta@niser.ac.in

    2017-04-15

    We report a systematic study on the anisotropy symmetry, magnetic domains and magnetic relaxation behavior in Co thin films deposited on MgO (001) substrate by varying (i) the pre-annealing condition and (ii) the speed of substrate rotation during deposition. Substrate annealing prior to deposition leads to the formation of textured thin films. On contrary Co films prepared without substrate pre-annealing exhibit polycrystalline nature. Surface topography imaged by atomic force microscopy (AFM) depicts a profound effect of growth condition on grain size and its distribution. Magnetic hysteresis measurement along with simultaneous domain imaging has been performed by magneto optic Kerr effect (MOKE) based microscope by varying the angle (ϕ) between the easy axis and the direction of applied magnetic field. We observed the existence of cubic and uniaxial anisotropy due to the presence of substrate annealing and oblique angular deposition, respectively. Along the easy axis, magnetization reversal is governed by 180° domain wall motion via branched domains. However, for easy axis<ϕrelaxation behavior under constant magnetic field strongly depends on the size and distribution of the grains. - Highlights: • This article provides a systematic study of textured growth of Co on MgO(001) substrate. • The structure has clear implication on the magnetic properties. • The magnetic relaxation has been studied for both textured and polycrystalline films.

  2. Asymptotically anti-de Sitter spacetimes and scalar fields with a logarithmic branch

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo; Zanelli, Jorge

    2004-01-01

    We consider a self-interacting scalar field whose mass saturates the Breitenlohner-Freedman bound, minimally coupled to Einstein gravity with a negative cosmological constant in D≥3 dimensions. It is shown that the asymptotic behavior of the metric has a slower fall-off than that of pure gravity with a localized distribution of matter, due to the back-reaction of the scalar field, which has a logarithmic branch decreasing as r -(D-1)/2 ln r for large radius r. We find the asymptotic conditions on the fields which are invariant under the same symmetry group as pure gravity with negative cosmological constant (conformal group in D-1 dimensions). The generators of the asymptotic symmetries are finite even when the logarithmic branch is considered but acquire, however, a contribution from the scalar field

  3. Global asymptotic stability of a delayed SEIRS epidemic model with saturation incidence

    International Nuclear Information System (INIS)

    Zhang Tailei; Teng Zhidong

    2008-01-01

    In this paper, the asymptotic behavior of solutions of an autonomous SEIRS epidemic model with the saturation incidence is studied. Using the method of Liapunov-LaSalle invariance principle, we obtain the disease-free equilibrium is globally stable if the basic reproduction number is not greater than one. Moreover, we show that the disease is permanent if the basic reproduction number is greater than one. Furthermore, the sufficient conditions of locally and globally asymptotically stable convergence to an endemic equilibrium are obtained base on the permanence

  4. Journal Afrika Statistika ISSN 0852-0305 Asymptotic representation ...

    African Journals Online (AJOL)

    Asymptotic representation theorems for poverty indices ... Statistical asymptotic laws for these indices, particularly asymptotic normality, on which statistical inference on the ... population of individuals, each of which having a random income or ...

  5. Asymptotic safety, emergence and minimal length

    International Nuclear Information System (INIS)

    Percacci, Roberto; Vacca, Gian Paolo

    2010-01-01

    There seems to be a common prejudice that asymptotic safety is either incompatible with, or at best unrelated to, the other topics in the title. This is not the case. In fact, we show that (1) the existence of a fixed point with suitable properties is a promising way of deriving emergent properties of gravity, and (2) there is a sense in which asymptotic safety implies a minimal length. In doing so we also discuss possible signatures of asymptotic safety in scattering experiments.

  6. Perils of Asymptotics

    International Nuclear Information System (INIS)

    Dewar, R. L.

    1995-01-01

    A large part of physics consists of learning which asymptotic methods to apply where, yet physicists are not always taught asymptotics in a systematic way. Asymptotology is given using an example from aerodynamics, and a rent Phys. Rev. Letter Comment is used as a case study of one subtle way things can go wrong. It is shown that the application of local analysis leads to erroneous conclusions regarding the existence of a continuous spectrum in a simple test problem, showing that a global analysis must be used. The final section presents results on a more sophisticated example, namely the WKBJ solution of Mathieu equation. 13 refs., 2 figs

  7. Asymptotic Poincare lemma and its applications

    International Nuclear Information System (INIS)

    Ziolkowski, R.W.; Deschamps, G.A.

    1984-01-01

    An asymptotic version of Poincare's lemma is defined and solutions are obtained with the calculus of exterior differential forms. They are used to construct the asymptotic approximations of multidimensional oscillatory integrals whose forms are commonly encountered, for example, in electromagnetic problems. In particular, the boundary and stationary point evaluations of these integrals are considered. The former is applied to the Kirchhoff representation of a scalar field diffracted through an aperture and simply recovers the Maggi-Rubinowicz-Miyamoto-Wolf results. Asymptotic approximations in the presence of other (standard) critical points are also discussed. Techniques developed for the asymptotic Poincare lemma are used to generate a general representation of the Leray form. All of the (differential form) expressions presented are generalizations of known (vector calculus) results. 14 references, 4 figures

  8. Renormalization group and asymptotic freedom

    International Nuclear Information System (INIS)

    Morris, J.R.

    1978-01-01

    Several field theoretic models are presented which allow exact expressions of the renormalization constants and renormalized coupling constants. These models are analyzed as to their content of asymptotic free field behavior through the use of the Callan-Symanzik renormalization group equation. It is found that none of these models possesses asymptotic freedom in four dimensions

  9. Properties of the relaxation time distribution underlying the Kohlrausch-Williams-Watts photoionization of the DX centers in Cd{sub 1-x}Mn{sub x}Te mixed crystals

    Energy Technology Data Exchange (ETDEWEB)

    Trzmiel, J; Weron, K; Placzek-Popko, E [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Janczura, J [Hugo Steinhaus Center for Stochastic Methods and Institute of Mathematics and Computer Science, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2009-08-26

    In this paper we clarify the relationship between the relaxation rate and relaxation time distributions underlying the Kohlrausch-Williams-Watts (KWW) photoconductivity build-ups in indium- and gallium-doped Cd{sub 1-x}Mn{sub x}Te mixed crystals. We discuss the role of asymptotic properties of the corresponding probability density functions. We show that the relaxation rate distribution, as a completely asymmetric alpha-stable distribution, leads to an infinite mean value of the effective relaxation rate. In contrast, the relaxation time distribution related to it leads to a finite mean value of the effective relaxation time. It follows from the experimental data analysis that for all the investigated samples the KWW exponent alpha decreases linearly with increasing photon flux in the range of (0.6-0.99) and its values are more spread in the case of gallium-doped material. We also observe a linear dependence of the mean relaxation time on the characteristic material time constant, which is consistent with the theoretical model.

  10. Adaptive Asymptotical Synchronization for Stochastic Complex Networks with Time-Delay and Markovian Switching

    Directory of Open Access Journals (Sweden)

    Xueling Jiang

    2014-01-01

    Full Text Available The problem of adaptive asymptotical synchronization is discussed for the stochastic complex dynamical networks with time-delay and Markovian switching. By applying the stochastic analysis approach and the M-matrix method for stochastic complex networks, several sufficient conditions to ensure adaptive asymptotical synchronization for stochastic complex networks are derived. Through the adaptive feedback control techniques, some suitable parameters update laws are obtained. Simulation result is provided to substantiate the effectiveness and characteristics of the proposed approach.

  11. A multiscale asymptotic analysis of time evolution equations on the complex plane

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Gastão A., E-mail: gbraga@mat.ufmg.br [Departamento de Matemática, Universidade Federal de Minas Gerais, Caixa Postal 702, 30161-970 Belo Horizonte, MG (Brazil); Conti, William R. P., E-mail: wrpconti@gmail.com [Departamento de Ciências do Mar, Universidade Federal de São Paulo, Rua Dr. Carvalho de Mendonça 144, 11070-100 Santos, SP (Brazil)

    2016-07-15

    Using an appropriate norm on the space of entire functions, we extend to the complex plane the renormalization group method as developed by Bricmont et al. The method is based upon a multiscale approach that allows for a detailed description of the long time asymptotics of solutions to initial value problems. The time evolution equation considered here arises in the study of iterations of the block spin renormalization group transformation for the hierarchical N-vector model. We show that, for initial conditions belonging to a certain Fréchet space of entire functions of exponential type, the asymptotics is universal in the sense that it is dictated by the fixed point of a certain operator acting on the space of initial conditions.

  12. Asymptotics of Laplace-Dirichlet integrals

    International Nuclear Information System (INIS)

    Kozlov, S.M.

    1990-01-01

    Here we consider the problem of the asymptotic expansion of the Laplace-Dirichlet integral. In homogenization theory such an integral represents the energy, and in general depends on the cohomology class. Here the asymptotic behaviour of this integral is found. The full text will appear in Functional Analysis and Applications, 1990, No.2. (author). 3 refs

  13. Dirac relaxation of the Israel junction conditions: Unified Randall-Sundrum brane theory

    International Nuclear Information System (INIS)

    Davidson, Aharon; Gurwich, Ilya

    2006-01-01

    Following Dirac's brane variation prescription, the brane must not be deformed during the variation process, or else the linearity of the variation may be lost. Alternatively, the variation of the brane is done, in a special Dirac frame, by varying the bulk coordinate system itself. Imposing appropriate Dirac-style boundary conditions on the constrained 'sandwiched' gravitational action, we show how Israel junction conditions get relaxed, but remarkably, all solutions of the original Israel equations are still respected. The Israel junction conditions are traded, in the Z 2 -symmetric case, for a generalized Regge-Teitelboim type equation (plus a local conservation law), and in the generic Z 2 -asymmetric case, for a pair of coupled Regge-Teitelboim equations. The Randall-Sundrum model and its derivatives, such as the Dvali-Gabadadze-Porrati and the Collins-Holdom models, get generalized accordingly. Furthermore, Randall-Sundrum and Regge-Teitelboim brane theories appear now to be two different faces of the one and the same unified brane theory. Within the framework of unified brane cosmology, we examine the dark matter/energy interpretation of the effective energy/momentum deviations from general relativity

  14. Asymptotic behaviour near extinction of continuous-state branching processes

    OpenAIRE

    Berzunza, Gabriel; Pardo, Juan Carlos

    2016-01-01

    In this note, we study the asymptotic behaviour near extinction of (sub-) critical continuous state branching processes. In particular, we establish an analogue of Khintchin's law of the iterated logarithm near extinction time for a continuous state branching process whose branching mechanism satisfies a given condition and its reflected process at its infimum.

  15. Trinucleon asymptotic normalization constants including Coulomb effects

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Lehman, D.R.; Payne, G.L.

    1982-01-01

    Exact theoretical expressions for calculating the trinucleon S- and D-wave asymptotic normalization constants, with and without Coulomb effects, are presented. Coordinate-space Faddeev-type equations are used to generate the trinucleon wave functions, and integral relations for the asymptotic norms are derived within this framework. The definition of the asymptotic norms in the presence of the Coulomb interaction is emphasized. Numerical calculations are carried out for the s-wave NN interaction models of Malfliet and Tjon and the tensor force model of Reid. Comparison with previously published results is made. The first estimate of Coulomb effects for the D-wave asymptotic norm is given. All theoretical values are carefully compared with experiment and suggestions are made for improving the experimental situation. We find that Coulomb effects increase the 3 He S-wave asymptotic norm by less than 1% relative to that of 3 H, that Coulomb effects decrease the 3 He D-wave asymptotic norm by approximately 8% relative to that of 3 H, and that the distorted-wave Born approximation D-state parameter, D 2 , is only 1% smaller in magnitude for 3 He than for 3 H due to compensating Coulomb effects

  16. Generalized Asymptotically Almost Periodic and Generalized Asymptotically Almost Automorphic Solutions of Abstract Multiterm Fractional Differential Inclusions

    Directory of Open Access Journals (Sweden)

    G. M. N’Guérékata

    2018-01-01

    Full Text Available The main aim of this paper is to investigate generalized asymptotical almost periodicity and generalized asymptotical almost automorphy of solutions to a class of abstract (semilinear multiterm fractional differential inclusions with Caputo derivatives. We illustrate our abstract results with several examples and possible applications.

  17. Dynamical renormalization group approach to relaxation in quantum field theory

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de

    2003-01-01

    The real time evolution and relaxation of expectation values of quantum fields and of quantum states are computed as initial value problems by implementing the dynamical renormalization group (DRG). Linear response is invoked to set up the renormalized initial value problem to study the dynamics of the expectation value of quantum fields. The perturbative solution of the equations of motion for the field expectation values of quantum fields as well as the evolution of quantum states features secular terms, namely terms that grow in time and invalidate the perturbative expansion for late times. The DRG provides a consistent framework to resum these secular terms and yields a uniform asymptotic expansion at long times. Several relevant cases are studied in detail, including those of threshold infrared divergences which appear in gauge theories at finite temperature and lead to anomalous relaxation. In these cases the DRG is shown to provide a resummation akin to Bloch-Nordsieck but directly in real time and that goes beyond the scope of Bloch-Nordsieck and Dyson resummations. The nature of the resummation program is discussed in several examples. The DRG provides a framework that is consistent, systematic, and easy to implement to study the non-equilibrium relaxational dynamics directly in real time that does not rely on the concept of quasiparticle widths

  18. Escape time, relaxation, and sticky states of a softened Henon-Heiles model: Low-frequency vibrational mode effects and glass relaxation

    Science.gov (United States)

    Toledo-Marín, J. Quetzalcóatl; Naumis, Gerardo G.

    2018-04-01

    Here we study the relaxation of a chain consisting of three masses joined by nonlinear springs and periodic conditions when the stiffness is weakened. This system, when expressed in their normal coordinates, yields a softened Henon-Heiles system. By reducing the stiffness of one low-frequency vibrational mode, a faster relaxation is enabled. This is due to a reduction of the energy barrier heights along the softened normal mode as well as for a widening of the opening channels of the energy landscape in configurational space. The relaxation is for the most part exponential, and can be explained by a simple flux equation. Yet, for some initial conditions the relaxation follows as a power law, and in many cases there is a regime change from exponential to power-law decay. We pinpoint the initial conditions for the power-law decay, finding two regions of sticky states. For such states, quasiperiodic orbits are found since almost for all components of the initial momentum orientation, the system is trapped inside two pockets of configurational space. The softened Henon-Heiles model presented here is intended as the simplest model in order to understand the interplay of rigidity, nonlinear interactions and relaxation for nonequilibrium systems such as glass-forming melts or soft matter. Our softened system can be applied to model β relaxation in glasses and suggest that local reorientational jumps can have an exponential and a nonexponential contribution for relaxation, the latter due to asymmetric molecules sticking in cages for certain orientations.

  19. Asymptotic state discrimination and a strict hierarchy in distinguishability norms

    Energy Technology Data Exchange (ETDEWEB)

    Chitambar, Eric [Department of Physics and Astronomy, Southern Illinois University, Carbondale, Illinois 62901 (United States); Hsieh, Min-Hsiu [Centre for Quantum Computation and Intelligent Systems (QCIS), Faculty of Engineering and Information Technology (FEIT), University of Technology Sydney - UTS, NSW 2007 (Australia)

    2014-11-15

    In this paper, we consider the problem of discriminating quantum states by local operations and classical communication (LOCC) when an arbitrarily small amount of error is permitted. This paradigm is known as asymptotic state discrimination, and we derive necessary conditions for when two multipartite states of any size can be discriminated perfectly by asymptotic LOCC. We use this new criterion to prove a gap in the LOCC and separable distinguishability norms. We then turn to the operational advantage of using two-way classical communication over one-way communication in LOCC processing. With a simple two-qubit product state ensemble, we demonstrate a strict majorization of the two-way LOCC norm over the one-way norm.

  20. Asymptotic behaviour of the scattering phase for non-trapping metrics

    International Nuclear Information System (INIS)

    Popov, G.S.

    1982-01-01

    The asymptotic behaviour of the scattering phase is considered at infinity for an elliptic, self-adjoint, second order differential operator H, defined either in Rsup(n) or in an unbounded domain Ω contains Rsup(n) with Dirichlet or Neumann boundary conditions. The operator H has the form H=- δsub(g)+hD+V where δsub(g) is the Laplace-Beltrami operator related to a Riemann metric g in anti Ω. Provided a non-trapping hypothesis is fulfilled and H coincides with the Laplace operator δ in a neighbourhood of infinity, an asymptotic development of the scattering phase s(lambda) is obtained for lambda → infinity. The first coefficients in this development are found

  1. Stress relaxation in viscous soft spheres.

    Science.gov (United States)

    Boschan, Julia; Vasudevan, Siddarth A; Boukany, Pouyan E; Somfai, Ellák; Tighe, Brian P

    2017-10-04

    We report the results of molecular dynamics simulations of stress relaxation tests in athermal viscous soft sphere packings close to their unjamming transition. By systematically and simultaneously varying both the amplitude of the applied strain step and the pressure of the initial condition, we access both linear and nonlinear response regimes and control the distance to jamming. Stress relaxation in viscoelastic solids is characterized by a relaxation time τ* that separates short time scales, where viscous loss is substantial, from long time scales, where elastic storage dominates and the response is essentially quasistatic. We identify two distinct plateaus in the strain dependence of the relaxation time, one each in the linear and nonlinear regimes. The height of both plateaus scales as an inverse power law with the distance to jamming. By probing the time evolution of particle velocities during relaxation, we further identify a correlation between mechanical relaxation in the bulk and the degree of non-affinity in the particle velocities on the micro scale.

  2. Asymptotically warped anti-de Sitter spacetimes in topologically massive gravity

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2011-01-01

    Asymptotically warped AdS spacetimes in topologically massive gravity with negative cosmological constant are considered in the case of spacelike stretched warping, where black holes have been shown to exist. We provide a set of asymptotic conditions that accommodate solutions in which the local degree of freedom (the ''massive graviton'') is switched on. An exact solution with this property is explicitly exhibited and possesses a slower falloff than the warped AdS black hole. The boundary conditions are invariant under the semidirect product of the Virasoro algebra with a u(1) current algebra. We show that the canonical generators are integrable and finite. When the graviton is not excited, our analysis is compared and contrasted with earlier results obtained through the covariant approach to conserved charges. In particular, we find agreement with the conserved charges of the warped AdS black holes as well as with the central charges in the algebra.

  3. Asymptotic expansions of Mathieu functions in wave mechanics

    International Nuclear Information System (INIS)

    Hunter, G.; Kuriyan, M.

    1976-01-01

    Solutions of the radial Schroedinger equation containing a polarization potential r -4 are expanded in a form appropriate for large values of r. These expansions of the Mathieu functions are used in association with the numerical solution of the Schroedinger equation to impose the asymptotic boundary condition in the case of bound states, and to extract phase shifts in the case of scattering states

  4. Relaxed states of tokamak plasmas

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Okano, V.

    1993-01-01

    The relaxed states of tokamak plasmas are studied. It is assumed that the plasma relaxes to a quasi-steady state which is characterized by a minimum entropy production rate, compatible with a number of prescribed conditions and pressure balance. A poloidal current arises naturally due to the anisotropic resistivity. The minimum entropy production theory is applied, assuming the pressure equilibrium as fundamental constraint on the final state. (L.C.J.A.)

  5. On asymptotic continuity of functions of quantum states

    International Nuclear Information System (INIS)

    Synak-Radtke, Barbara; Horodecki, Michal

    2006-01-01

    A useful kind of continuity of quantum states functions in asymptotic regime is so-called asymptotic continuity. In this letter, we provide general tools for checking if a function possesses this property. First we prove equivalence of asymptotic continuity with so-called robustness under admixture. This allows us to show that relative entropy distance from a convex set including a maximally mixed state is asymptotically continuous. Subsequently, we consider arrowing-a way of building a new function out of a given one. The procedure originates from constructions of intrinsic information and entanglement of formation. We show that arrowing preserves asymptotic continuity for a class of functions (so-called subextensive ones). The result is illustrated by means of several examples. (letter to the editor)

  6. Asymptotics of eigenvalues and eigenvectors of Toeplitz matrices

    Science.gov (United States)

    Böttcher, A.; Bogoya, J. M.; Grudsky, S. M.; Maximenko, E. A.

    2017-11-01

    Analysis of the asymptotic behaviour of the spectral characteristics of Toeplitz matrices as the dimension of the matrix tends to infinity has a history of over 100 years. For instance, quite a number of versions of Szegő's theorem on the asymptotic behaviour of eigenvalues and of the so-called strong Szegő theorem on the asymptotic behaviour of the determinants of Toeplitz matrices are known. Starting in the 1950s, the asymptotics of the maximum and minimum eigenvalues were actively investigated. However, investigation of the individual asymptotics of all the eigenvalues and eigenvectors of Toeplitz matrices started only quite recently: the first papers on this subject were published in 2009-2010. A survey of this new field is presented here. Bibliography: 55 titles.

  7. On the late phase of relaxation of two-dimensional fluids: turbulence of unitons

    International Nuclear Information System (INIS)

    Spineanu, F; Vlad, M

    2017-01-01

    The two-dimensional ideal fluid and the plasma confined by a strong magnetic field exhibit an intrinsic tendency to organization due to the inverse spectral cascade. In the asymptotic states reached at relaxation the turbulence has vanished and there are only coherent vortical structures. We are interested in the regime that precedes these ordered flow patterns, in which there still is turbulence and imperfect but robust structures have emerged. To develop an analytical description we propose to start from the stationary coherent states and (in the direction opposite to relaxation) explore the space of configurations before the extremum of the functional that defines the structures has been reached. We find necessary to assemble different but related models: point-like vortices, its field theoretical formulation as interacting matter and gauge fields, chiral model and surfaces with constant mean curvature. These models are connected by the similar ability to described randomly interacting coherent structures. They derive exactly the same equation for the asymptotic state (sinh-Poisson equation, confirmed by numerical calculation of fluid flows). The chiral model, to which one can arrive from self-duality equation of the field theoretical model for fluid and from constant mean curvature surface equations, appears to be the suitable analytical framework. Its solutions, the unitons, aquire dynamics when the system is not at the extremum of the action. In the present work we provide arguments that the underlying common nature of these models can be used to develop an approach to fluid and plasma states of turbulence interacting with structures. (paper)

  8. Stationary solutions and asymptotic flatness I

    International Nuclear Information System (INIS)

    Reiris, Martin

    2014-01-01

    In general relativity, a stationary isolated system is defined as an asymptotically flat (AF) stationary spacetime with compact material sources. Other definitions that are less restrictive on the type of asymptotic could in principle be possible. Between this article and its sequel, we show that under basic assumptions, asymptotic flatness indeed follows as a consequence of Einstein's theory. In particular, it is proved that any vacuum stationary spacetime-end whose (quotient) manifold is diffeomorphic to R 3 minus a ball and whose Killing field has its norm bounded away from zero, is necessarily AF with Schwarzschildian fall off. The ‘excised’ ball would contain (if any) the actual material body, but this information is unnecessary to reach the conclusion. In this first article, we work with weakly asymptotically flat (WAF) stationary ends, a notion that generalizes as much as possible that of the AF end, and prove that WAF ends are AF with Schwarzschildian fall off. Physical and mathematical implications are also discussed. (paper)

  9. Asymptotic variance of grey-scale surface area estimators

    DEFF Research Database (Denmark)

    Svane, Anne Marie

    Grey-scale local algorithms have been suggested as a fast way of estimating surface area from grey-scale digital images. Their asymptotic mean has already been described. In this paper, the asymptotic behaviour of the variance is studied in isotropic and sufficiently smooth settings, resulting...... in a general asymptotic bound. For compact convex sets with nowhere vanishing Gaussian curvature, the asymptotics can be described more explicitly. As in the case of volume estimators, the variance is decomposed into a lattice sum and an oscillating term of at most the same magnitude....

  10. Nonlinear mechanics of thin-walled structures asymptotics, direct approach and numerical analysis

    CERN Document Server

    Vetyukov, Yury

    2014-01-01

    This book presents a hybrid approach to the mechanics of thin bodies. Classical theories of rods, plates and shells with constrained shear are based on asymptotic splitting of the equations and boundary conditions of three-dimensional elasticity. The asymptotic solutions become accurate as the thickness decreases, and the three-dimensional fields of stresses and displacements can be determined. The analysis includes practically important effects of electromechanical coupling and material inhomogeneity. The extension to the geometrically nonlinear range uses the direct approach based on the principle of virtual work. Vibrations and buckling of pre-stressed structures are studied with the help of linearized incremental formulations, and direct tensor calculus rounds out the list of analytical techniques used throughout the book. A novel theory of thin-walled rods of open profile is subsequently developed from the models of rods and shells, and traditionally applied equations are proven to be asymptotically exa...

  11. Stress induced conditioning and thermal relaxation in the simulation of quasi-static compression experiments

    International Nuclear Information System (INIS)

    Scalerandi, M; Delsanto, P P; Johnson, P A

    2003-01-01

    Local interaction simulation approach simulations of the ultrasonic wave propagation in multi-grained materials have succeeded in reproducing most of the recently observed nonclassical nonlinear effects, such as stress-strain hysteresis and discrete memory in quasi-static experiments and a downwards shift of the resonance frequency and the generation of odd harmonics at specific amplitude rates in dynamics experiments. By including a simple mechanism of thermally activated random transitions, we can predict the occurrence of experimentally observed effects, such as the conditioning and relaxation of the specimen. Experiments are also suggested for a quantitative assessment of the validity of the model

  12. Stress induced conditioning and thermal relaxation in the simulation of quasi-static compression experiments

    CERN Document Server

    Scalerandi, M; Johnson, P A

    2003-01-01

    Local interaction simulation approach simulations of the ultrasonic wave propagation in multi-grained materials have succeeded in reproducing most of the recently observed nonclassical nonlinear effects, such as stress-strain hysteresis and discrete memory in quasi-static experiments and a downwards shift of the resonance frequency and the generation of odd harmonics at specific amplitude rates in dynamics experiments. By including a simple mechanism of thermally activated random transitions, we can predict the occurrence of experimentally observed effects, such as the conditioning and relaxation of the specimen. Experiments are also suggested for a quantitative assessment of the validity of the model.

  13. State Estimation for a Biological Phosphorus Removal Process using an Asymptotic Observer

    DEFF Research Database (Denmark)

    Larose, Claude Alain; Jørgensen, Sten Bay

    2001-01-01

    This study investigated the use of an asymptotic observer for state estimation in a continuous biological phosphorus removal process. The estimated states are the concentration of heterotrophic, autotrophic, and phosphorus accumulating organisms, polyphosphate, glycogen and PHA. The reaction scheme...... if the convergence, driven by the dilution rate, was slow (from 15 to 60 days). The propagation of the measurement noise and a bias in the estimation of glycogen and PHA could be the result of the high condition number of one of the matrices used in the algorithm of the asymptotic observer for the aerated tanks....

  14. Gravitational collapse in asymptotically anti-de Sitter or de Sitter backgrounds

    International Nuclear Information System (INIS)

    Madhav, T. Arun; Goswami, Rituparno; Joshi, Pankaj S.

    2005-01-01

    We study here the gravitational collapse of a matter cloud with a nonvanishing tangential pressure in the presence of a nonzero cosmological term Λ. It is investigated how Λ modifies the dynamics of the collapsing cloud and whether it affects the cosmic censorship. Conditions for bounce and singularity formation are derived. It is seen that when the tangential pressure vanishes, the bounce and singularity conditions reduce to the dust case studied earlier. The collapsing interior is matched to an exterior which is asymptotically de Sitter or anti-de Sitter, depending on the sign of the cosmological constant. The junction conditions for matching the cloud to the exterior are specified. The effect of Λ on apparent horizons is studied in some detail and the nature of central singularity is analyzed. The visibility of singularity and implications for the cosmic censorship conjecture are discussed. It is shown that for a nonvanishing cosmological constant, both black hole and naked singularities do form as collapse end states in spacetimes which are asymptotically de Sitter or anti-de Sitter

  15. The Effect of Relaxation Interventions on Cortisol Levels in HIV-Sero-Positive Women

    Science.gov (United States)

    Jones, Deborah; Owens, Mary; Kumar, Mahendra; Cook, Ryan; Weiss, Stephen M.

    2016-01-01

    Purpose Activation of the hypothalamic–pituitary–adrenal axis, assessed in terms of cortisol levels, may enhance the ability of HIV to infect lymphocytes and downregulate the immune system, accelerating disease progression. This study sought to determine the effects of relaxation techniques on cortisol levels in HIV-sero-positive women. Methods Women (n = 150) were randomized to a group cognitive–behavioral stress management (CBSM) condition or an individual information condition and underwent 3 types of relaxation training (progressive muscle relaxation, imagery, and autogenic training). Cortisol levels were obtained pre- and postrelaxation. Results Guided imagery was effective in reducing cortisol in the group condition (t = 3.90, P < .001), and muscle relaxation reduced cortisol in the individual condition (t = 3.11, P = .012). Among participants in the group condition attending all sessions, the magnitude of pre- to postsession reduction became greater over time. Conclusions Results suggest that specific relaxation techniques may be partially responsible for cortisol decreases associated with relaxation and CBSM. PMID:23715264

  16. Asymptotic analysis for Nakagami-m fading channels with relay selection

    KAUST Repository

    Zhong, Caijun

    2011-06-01

    In this paper, we analyze the asymptotic outage probability performance of both decode-and-forward (DF) and amplify-and-forward (AF) relaying systems using partial relay selection and the "best" relay selection schemes for Nakagami-m fading channels. We derive their respective outage probability expressions in the asymptotic high signal-to-noise ratio (SNR) regime, from which the diversity order and coding gain are analyzed. In addition, we investigate the impact of power allocation between the source and relay terminals and derive the diversity-multiplexing tradeoff (DMT) for these relay selection systems. The theoretical findings suggest that partial relay selection can improve the diversity of the system and can achieve the same DMT as the "best" relay selection scheme under certain conditions. © 2011 IEEE.

  17. Theorems for asymptotic safety of gauge theories

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Andrew D.; Litim, Daniel F. [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom)

    2017-06-15

    We classify the weakly interacting fixed points of general gauge theories coupled to matter and explain how the competition between gauge and matter fluctuations gives rise to a rich spectrum of high- and low-energy fixed points. The pivotal role played by Yukawa couplings is emphasised. Necessary and sufficient conditions for asymptotic safety of gauge theories are also derived, in conjunction with strict no go theorems. Implications for phase diagrams of gauge theories and physics beyond the Standard Model are indicated. (orig.)

  18. Asymptotics of the $s$-perimeter as $s\\searrow 0$

    OpenAIRE

    Dipierro, Serena; Figalli, Alessio; Palatucci, Giampiero; Valdinoci, Enrico

    2012-01-01

    We deal with the asymptotic behavior of the $s$-perimeter of a set $E$ inside a domain $\\Omega$ as $s\\searrow0$. We prove necessary and sufficient conditions for the existence of such limit, by also providing an explicit formulation in terms of the Lebesgue measure of $E$ and $\\Omega$. Moreover, we construct examples of sets for which the limit does not exist.

  19. Quantum Hall resistance standard in graphene devices under relaxed experimental conditions

    Science.gov (United States)

    Schopfer, F.; Ribeiro-Palau, R.; Lafont, F.; Brun-Picard, J.; Kazazis, D.; Michon, A.; Cheynis, F.; Couturaud, O.; Consejo, C.; Jouault, B.; Poirier, W.

    Large-area and high-quality graphene devices synthesized by CVD on SiC are used to develop reliable electrical resistance standards, based on the quantum Hall effect (QHE), with state-of-the-art accuracy of 1x10-9 and under an extended range of experimental conditions of magnetic field (down to 3.5 T), temperature (up to 10 K) or current (up to 0.5 mA). These conditions are much relaxed as compared to what is required by GaAs/AlGaAs standards and will enable to broaden the use of the primary quantum electrical standards to the benefit of Science and Industry for electrical measurements. Furthermore, by comparison of these graphene devices with GaAs/AlGaAs standards, we demonstrate the universality of the QHE within an ultimate uncertainty of 8.2x10-11. This suggests the exact relation of the quantized Hall resistance with the Planck constant and the electron charge, which is crucial for the new SI to be based on fixing such fundamental constants. These results show that graphene realizes its promises and demonstrates its superiority over other materials for a demanding application. Nature Nanotech. 10, 965-971, 2015, Nature Commun. 6, 6806, 2015

  20. Asymptotic stabilization of nonlinear systems using state feedback

    International Nuclear Information System (INIS)

    D'Attellis, Carlos

    1990-01-01

    This paper studies the design of state-feedback controllers for the stabilization of single-input single-output nonlinear systems x = f(x) + g(x)u, y = h(x). Two approaches for the stabilization problem are given; the asymptotic stability is achieved by means of: a) nonlinear state feedback: two nonlinear feedbacks are used; the first separates the system in a controllable linear part and in the zeros-dynamic part. The second feedback generates an asymptotically stable equilibrium on the manifold where this dynamics evolves; b) nonlinear dynamic feedback: conditions are established under which the system can follow the output of a completely controllable bilinear system which uses bounded controls. This fact enables the system to reach, using bounded controls too, a desired output value in finite time. As this value corresponds to a state that lays in the attraction basin of a stable equilibrium with the same output, the system evolves to that point. The two methods are illustrated by examples. (Author) [es

  1. AdS-like spectrum of the asymptotically Goedel space-times

    International Nuclear Information System (INIS)

    Konoplya, R. A.; Zhidenko, A.

    2011-01-01

    A black hole immersed in a rotating universe, described by the Gimon-Hashimoto solution, is tested on stability against scalar field perturbations. Unlike the previous studies on perturbations of this solution, which dealt only with the limit of slow universe rotation j, we managed to separate variables in the perturbation equation for the general case of arbitrary rotation. This leads to qualitatively different dynamics of perturbations, because the exact effective potential does not allow for Schwarzschild-like asymptotic of the wave function in the form of purely outgoing waves. The Dirichlet boundary conditions are allowed instead, which result in a totally different spectrum of asymptotically Goedel black holes: the spectrum of quasinormal frequencies is similar to the one of asymptotically anti-de Sitter black holes. At large and intermediate overtones N, the spectrum is equidistant in N. In the limit of small black holes, quasinormal modes (QNMs) approach the normal modes of the empty Goedel space-time. There is no evidence of instability in the found frequencies, which supports the idea that the existence of closed timelike curves (CTCs) and the onset of instability correlate (if at all) not in a straightforward way.

  2. Asymptotic Conservation Laws in Classical Field Theory

    International Nuclear Information System (INIS)

    Anderson, I.M.; Torre, C.G.

    1996-01-01

    A new, general, field theoretic approach to the derivation of asymptotic conservation laws is presented. In this approach asymptotic conservation laws are constructed directly from the field equations according to a universal prescription which does not rely upon the existence of Noether identities or any Lagrangian or Hamiltonian formalisms. The resulting general expressions of the conservation laws enjoy important invariance properties and synthesize all known asymptotic conservation laws, such as the Arnowitt-Deser-Misner energy in general relativity. copyright 1996 The American Physical Society

  3. Asymptotic description of plasma turbulence: Krylov-Bogoliubov methods and quasi-particles

    International Nuclear Information System (INIS)

    Sosenko, P.P.; Bertrand, P.; Decyk, V.K.

    2001-01-01

    The asymptotic theory of charged particle motion in electromagnetic fields is developed for the general case of finite Larmor-radius effects by means of Krylov-Bogoliubov averaging method. The correspondence between the general asymptotic methods, elaborated by M. Krylov and M.Bogoliubov, the quasi-particle description and gyrokinetics is established. Such a comparison is used to shed more light on the physical sense of the reduced Poisson equation, introduced in gyrokinetics, and the particle polarization drift. It is shown that the modification of the Poisson equation in the asymptotic theory is due to the non-conservation of the magnetic moment and gyrophase trembling. it is shown that the second-order modification of the adiabatic invariant can determine the conditions of global plasma stability and introduces new nonlinear terms into the reduced Poisson equation. Such a modification is important for several plasma orderings, e.g. NHD type ordering. The feasibility of numerical simulation schemes in which the polarization drift is included into the quasi-particle equations of motion, and the Poisson equation remains unchanged is analyzed. A consistent asymptotic model is proposed in which the polarization drift is included into the quasi-particle equations of motion and the particle and quasi-particle velocities are equal. It is shown that in such models there are additional modifications of the reduced Poisson equation. The latter becomes even more complicated in contrast to earlier suggestions

  4. Asymptotic symmetries, holography and topological hair

    Science.gov (United States)

    Mishra, Rashmish K.; Sundrum, Raman

    2018-01-01

    Asymptotic symmetries of AdS4 quantum gravity and gauge theory are derived by coupling the holographically dual CFT3 to Chern-Simons gauge theory and 3D gravity in a "probe" (large-level) limit. Despite the fact that the three-dimensional AdS4 boundary as a whole is consistent with only finite-dimensional asymptotic symmetries, given by AdS isometries, infinite-dimensional symmetries are shown to arise in circumstances where one is restricted to boundary subspaces with effectively two-dimensional geometry. A canonical example of such a restriction occurs within the 4D subregion described by a Wheeler-DeWitt wavefunctional of AdS4 quantum gravity. An AdS4 analog of Minkowski "super-rotation" asymptotic symmetry is probed by 3D Einstein gravity, yielding CFT2 structure (in a large central charge limit), via AdS3 foliation of AdS4 and the AdS3/CFT2 correspondence. The maximal asymptotic symmetry is however probed by 3D conformal gravity. Both 3D gravities have Chern-Simons formulation, manifesting their topological character. Chern-Simons structure is also shown to be emergent in the Poincare patch of AdS4, as soft/boundary limits of 4D gauge theory, rather than "put in by hand" as an external probe. This results in a finite effective Chern-Simons level. Several of the considerations of asymptotic symmetry structure are found to be simpler for AdS4 than for Mink4, such as non-zero 4D particle masses, 4D non-perturbative "hard" effects, and consistency with unitarity. The last of these in particular is greatly simplified because in some set-ups the time dimension is explicitly shared by each level of description: Lorentzian AdS4, CFT3 and CFT2. Relatedly, the CFT2 structure clarifies the sense in which the infinite asymptotic charges constitute a useful form of "hair" for black holes and other complex 4D states. An AdS4 analog of Minkowski "memory" effects is derived, but with late-time memory of earlier events being replaced by (holographic) "shadow" effects. Lessons

  5. Asymptotic work distributions in driven bistable systems

    International Nuclear Information System (INIS)

    Nickelsen, D; Engel, A

    2012-01-01

    The asymptotic tails of the probability distributions of thermodynamic quantities convey important information about the physics of nanoscopic systems driven out of equilibrium. We apply a recently proposed method to analytically determine the asymptotics of work distributions in Langevin systems to an one-dimensional model of single-molecule force spectroscopy. The results are in excellent agreement with numerical simulations, even in the centre of the distributions. We compare our findings with a recent proposal for an universal form of the asymptotics of work distributions in single-molecule experiments.

  6. Asymptotic freeze-out of the perturbations generated inside a corrugated rarefaction wave

    International Nuclear Information System (INIS)

    Wouchuk, J.G.; Serrano Rodrigo, A.D.

    2004-01-01

    Based on previous work [J. G. Wouchuk and R. Carretero, Phys. Plasmas 10, 4237 (2003)], the conditions of asymptotic freeze-out of the ripples at the tail of a corrugated rarefaction wave are analyzed. The precise location of the freezing-out regions in the space of preshock parameters is tried, and an efficient algorithm for their determination is given. It is seen that asymptotic freeze-out can only happen for gases that have an isentropic exponent γ cr ≅2.2913hellip. It is shown that the late time freeze-out of the ripple perturbations is correlated to the initial tangential velocity profile (at t=0+) inside the expansion fan

  7. Large gauge symmetries and asymptotic states in QED

    Energy Technology Data Exchange (ETDEWEB)

    Gabai, Barak; Sever, Amit [School of Physics and Astronomy, Tel Aviv University,Ramat Aviv 69978 (Israel)

    2016-12-19

    Large Gauge Transformations (LGT) are gauge transformations that do not vanish at infinity. Instead, they asymptotically approach arbitrary functions on the conformal sphere at infinity. Recently, it was argued that the LGT should be treated as an infinite set of global symmetries which are spontaneously broken by the vacuum. It was established that in QED, the Ward identities of their induced symmetries are equivalent to the Soft Photon Theorem. In this paper we study the implications of LGT on the S-matrix between physical asymptotic states in massive QED. In appose to the naively free scattering states, physical asymptotic states incorporate the long range electric field between asymptotic charged particles and were already constructed in 1970 by Kulish and Faddeev. We find that the LGT charge is independent of the particles’ momenta and may be associated to the vacuum. The soft theorem’s manifestation as a Ward identity turns out to be an outcome of not working with the physical asymptotic states.

  8. Asymptotic analysis and boundary layers

    CERN Document Server

    Cousteix, Jean

    2007-01-01

    This book presents a new method of asymptotic analysis of boundary-layer problems, the Successive Complementary Expansion Method (SCEM). The first part is devoted to a general comprehensive presentation of the tools of asymptotic analysis. It gives the keys to understand a boundary-layer problem and explains the methods to construct an approximation. The second part is devoted to SCEM and its applications in fluid mechanics, including external and internal flows. The advantages of SCEM are discussed in comparison with the standard Method of Matched Asymptotic Expansions. In particular, for the first time, the theory of Interactive Boundary Layer is fully justified. With its chapter summaries, detailed derivations of results, discussed examples and fully worked out problems and solutions, the book is self-contained. It is written on a mathematical level accessible to graduate and post-graduate students of engineering and physics with a good knowledge in fluid mechanics. Researchers and practitioners will estee...

  9. Spin Diffusion and Spin Lattice Relaxation of Dipolar Order in Solids Containing Paramagnetic Impurities

    International Nuclear Information System (INIS)

    Furman, G.B.; Panich, A.M.; Goren, S.D.

    1998-01-01

    The phenomena of spin diffusion and spin lattice relaxation of nuclear dipolar order in solids containing paramagnetic impurities (PI) is considered. We show that at the beginning of the relaxation process the diffusion vanishing regime realizes with non-exponential time dependence, R(t) ∼ exp [- (t/T 1d ) α ], where T 1d ∼ C p -1/α , C p is PI's concentration. For a homogeneous distribution of Pis and nuclear spins, α=Q/6, where Q is the sample dimensionality; for an inhomogeneous distribution, the sample is divided into q-dimensional subsystems, each containing one PI, yield- ing α= (Q + q) /6. This result coincides with experimental data for CaF 2 doped with 0.8 - 10 -3 ωt % of Mn 2+ , where the non-exponential decay of the dipolar signal with α= 0.83 has been observed [3]. Fitting the experimental data yields a good agreement with T 1d = 66 ms . For another independent check of the obtained results we use dependence of the relaxation time on impurities concentration. In accordance that 1/α=1.2 , we have T 1d ∼ C p -1 '. 2 . Exactly this dependence on impurity concentration of the relaxation time has been found in the experiment. Then the relaxation regime starts as a non-exponential time dependent, proceed asymptotically to an to an exponential function of time, to so called diffusion limited relaxation regime with relaxation time T 1d D is inversely depends on impurities concentration. This kind of relaxation behavior of the dipolar order takes place in the experiment [2]. Using experimental results [2] from this two regime we can estimate the diffusion coefficient of the nuclear dipolar order in CaF 2 , which gives for typical values of impurity concentration C p ∼ 10 18 cm 3 the diffusion coefficient of dipolar order in the interval D ∼ 10 -11 -i- 10 -12 cm 2 /sec which is coincide to the case of Zeeman energy spin diffusion

  10. Asymptotic theory for regressions with smoothly changing parameters

    DEFF Research Database (Denmark)

    Hillebrand, Eric; Medeiros, Marcelo; Xu, Junyue

    2013-01-01

    We derive asymptotic properties of the quasi maximum likelihood estimator of smooth transition regressions when time is the transition variable. The consistency of the estimator and its asymptotic distribution are examined. It is shown that the estimator converges at the usual pT-rate and has...... an asymptotically normal distribution. Finite sample properties of the estimator are explored in simulations. We illustrate with an application to US inflation and output data....

  11. Asymptotic Behaviour and Extinction of Delay Lotka-Volterra Model with Jump-Diffusion

    Directory of Open Access Journals (Sweden)

    Dan Li

    2014-01-01

    Full Text Available This paper studies the effect of jump-diffusion random environmental perturbations on the asymptotic behaviour and extinction of Lotka-Volterra population dynamics with delays. The contributions of this paper lie in the following: (a to consider delay stochastic differential equation with jumps, we introduce a proper initial data space, in which the initial data may be discontinuous function with downward jumps; (b we show that the delay stochastic differential equation with jumps associated with our model has a unique global positive solution and give sufficient conditions that ensure stochastically ultimate boundedness, moment average boundedness in time, and asymptotic polynomial growth of our model; (c the sufficient conditions for the extinction of the system are obtained, which generalized the former results and showed that the sufficiently large random jump magnitudes and intensity (average rate of jump events arrival may lead to extinction of the population.

  12. Large Deviations and Asymptotic Methods in Finance

    CERN Document Server

    Gatheral, Jim; Gulisashvili, Archil; Jacquier, Antoine; Teichmann, Josef

    2015-01-01

    Topics covered in this volume (large deviations, differential geometry, asymptotic expansions, central limit theorems) give a full picture of the current advances in the application of asymptotic methods in mathematical finance, and thereby provide rigorous solutions to important mathematical and financial issues, such as implied volatility asymptotics, local volatility extrapolation, systemic risk and volatility estimation. This volume gathers together ground-breaking results in this field by some of its leading experts. Over the past decade, asymptotic methods have played an increasingly important role in the study of the behaviour of (financial) models. These methods provide a useful alternative to numerical methods in settings where the latter may lose accuracy (in extremes such as small and large strikes, and small maturities), and lead to a clearer understanding of the behaviour of models, and of the influence of parameters on this behaviour. Graduate students, researchers and practitioners will find th...

  13. Asymptotic evolution of quantum Markov chains

    Energy Technology Data Exchange (ETDEWEB)

    Novotny, Jaroslav [FNSPE, CTU in Prague, 115 19 Praha 1 - Stare Mesto (Czech Republic); Alber, Gernot [Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

    2012-07-01

    The iterated quantum operations, so called quantum Markov chains, play an important role in various branches of physics. They constitute basis for many discrete models capable to explore fundamental physical problems, such as the approach to thermal equilibrium, or the asymptotic dynamics of macroscopic physical systems far from thermal equilibrium. On the other hand, in the more applied area of quantum technology they also describe general characteristic properties of quantum networks or they can describe different quantum protocols in the presence of decoherence. A particularly, an interesting aspect of these quantum Markov chains is their asymptotic dynamics and its characteristic features. We demonstrate there is always a vector subspace (typically low-dimensional) of so-called attractors on which the resulting superoperator governing the iterative time evolution of quantum states can be diagonalized and in which the asymptotic quantum dynamics takes place. As the main result interesting algebraic relations are presented for this set of attractors which allow to specify their dual basis and to determine them in a convenient way. Based on this general theory we show some generalizations concerning the theory of fixed points or asymptotic evolution of random quantum operations.

  14. On selfdual spin-connections and asymptotic safety

    Energy Technology Data Exchange (ETDEWEB)

    Harst, U., E-mail: harst@thep.physik.uni-mainz.de; Reuter, M., E-mail: reuter@thep.physik.uni-mainz.de

    2016-02-10

    We explore Euclidean quantum gravity using the tetrad field together with a selfdual or anti-selfdual spin-connection as the basic field variables. Setting up a functional renormalization group (RG) equation of a new type which is particularly suitable for the corresponding theory space we determine the non-perturbative RG flow within a two-parameter truncation suggested by the Holst action. We find that the (anti-)selfdual theory is likely to be asymptotically safe. The existing evidence for its non-perturbative renormalizability is comparable to that of Einstein–Cartan gravity without the selfduality condition.

  15. Asymptotic Theory for Regressions with Smoothly Changing Parameters

    DEFF Research Database (Denmark)

    Hillebrand, Eric Tobias; Medeiros, Marcelo C.; Xu, Junyue

    We derive asymptotic properties of the quasi maximum likelihood estimator of smooth transition regressions when time is the transition variable. The consistency of the estimator and its asymptotic distribution are examined. It is shown that the estimator converges at the usual square-root-of-T rate...... and has an asymptotically normal distribution. Finite sample properties of the estimator are explored in simulations. We illustrate with an application to US inflation and output data....

  16. Relaxation of the distribution function tails for gases with power-law interaction potentials

    International Nuclear Information System (INIS)

    Potapenko, I.F.; Bobylev, A.V.; de Azevedo, C.A.; de Assis, A.S.

    1997-01-01

    The relaxation of rarefied gases of particles with the power-law interaction potentials U=α/r s , where 1≤s<4, is considered. The formation and evolution of the distribution function tails are investigated on the basis of the one-dimensional kinetic Landau endash Fokker-Planck equation. For long times, the constructed asymptotic solutions have a propagating-wave appearance in the high velocity region. The analytical solutions are expressed explicitly in terms of the error function. The analytical consideration is accomplished by numerical calculations. The obtained analytical results are in a good agreement with the numerical simulation results. copyright 1997 The American Physical Society

  17. Asymptotic Value Distribution for Solutions of the Schroedinger Equation

    International Nuclear Information System (INIS)

    Breimesser, S. V.; Pearson, D. B.

    2000-01-01

    We consider the Dirichlet Schroedinger operator T=-(d 2 /d x 2 )+V, acting in L 2 (0,∞), where Vis an arbitrary locally integrable potential which gives rise to absolutely continuous spectrum. Without any other restrictive assumptions on the potential V, the description of asymptotics for solutions of the Schroedinger equation is carried out within the context of the theory of value distribution for boundary values of analytic functions. The large x asymptotic behaviour of the solution v(x,λ) of the equation Tf(x,λ)=λf(x,λ), for λ in the support of the absolutely continuous part μ a.c. of the spectral measure μ, is linked to the spectral properties of this measure which are determined by the boundary value of the Weyl-Titchmarsh m-function. Our main result (Theorem 1) shows that the value distribution for v'(N,λ)/v(N,λ) approaches the associated value distribution of the Herglotz function m N (z) in the limit N → ∞, where m N (z) is the Weyl-Titchmarsh m-function for the Schroedinger operator -(d 2 /d x 2 )+Vacting in L 2 (N,∞), with Dirichlet boundary condition at x=N. We will relate the analysis of spectral asymptotics for the absolutely continuous component of Schroedinger operators to geometrical properties of the upper half-plane, viewed as a hyperbolic space

  18. Asymptotic expansion of the Keesom integral

    International Nuclear Information System (INIS)

    Abbott, Paul C

    2007-01-01

    The asymptotic evaluation and expansion of the Keesom integral, K(a), is discussed at some length in Battezzati and Magnasco (2004 J. Phys. A: Math. Gen. 37 9677; 2005 J. Phys. A: Math. Gen. 38 6715). Here, using standard identities, it is shown that this triple integral can be reduced to a single integral from which the asymptotic behaviour is readily obtained using Laplace's method. (comment)

  19. AGB [asymptotic giant branch]: Star evolution

    International Nuclear Information System (INIS)

    Becker, S.A.

    1987-01-01

    Asymptotic giant branch stars are red supergiant stars of low-to-intermediate mass. This class of stars is of particular interest because many of these stars can have nuclear processed material brought up repeatedly from the deep interior to the surface where it can be observed. A review of recent theoretical and observational work on stars undergoing the asymptotic giant branch phase is presented. 41 refs

  20. Wijsman Orlicz Asymptotically Ideal -Statistical Equivalent Sequences

    Directory of Open Access Journals (Sweden)

    Bipan Hazarika

    2013-01-01

    in Wijsman sense and present some definitions which are the natural combination of the definition of asymptotic equivalence, statistical equivalent, -statistical equivalent sequences in Wijsman sense. Finally, we introduce the notion of Cesaro Orlicz asymptotically -equivalent sequences in Wijsman sense and establish their relationship with other classes.

  1. Asymptotic geometric analysis, part I

    CERN Document Server

    Artstein-Avidan, Shiri

    2015-01-01

    The authors present the theory of asymptotic geometric analysis, a field which lies on the border between geometry and functional analysis. In this field, isometric problems that are typical for geometry in low dimensions are substituted by an "isomorphic" point of view, and an asymptotic approach (as dimension tends to infinity) is introduced. Geometry and analysis meet here in a non-trivial way. Basic examples of geometric inequalities in isomorphic form which are encountered in the book are the "isomorphic isoperimetric inequalities" which led to the discovery of the "concentration phenomen

  2. Asymptotic safety guaranteed

    DEFF Research Database (Denmark)

    Litim, Daniel F.; Sannino, Francesco

    2014-01-01

    We study the ultraviolet behaviour of four-dimensional quantum field theories involving non-abelian gauge fields, fermions and scalars in the Veneziano limit. In a regime where asymptotic freedom is lost, we explain how the three types of fields cooperate to develop fully interacting ultraviolet ...

  3. Almost Surely Asymptotic Stability of Numerical Solutions for Neutral Stochastic Delay Differential Equations

    Directory of Open Access Journals (Sweden)

    Zhanhua Yu

    2011-01-01

    convergence theorem. It is shown that the Euler method and the backward Euler method can reproduce the almost surely asymptotic stability of exact solutions to NSDDEs under additional conditions. Numerical examples are demonstrated to illustrate the effectiveness of our theoretical results.

  4. Asymptotics of bivariate generating functions with algebraic singularities

    Science.gov (United States)

    Greenwood, Torin

    Flajolet and Odlyzko (1990) derived asymptotic formulae the coefficients of a class of uni- variate generating functions with algebraic singularities. Gao and Richmond (1992) and Hwang (1996, 1998) extended these results to classes of multivariate generating functions, in both cases by reducing to the univariate case. Pemantle and Wilson (2013) outlined new multivariate ana- lytic techniques and used them to analyze the coefficients of rational generating functions. After overviewing these methods, we use them to find asymptotic formulae for the coefficients of a broad class of bivariate generating functions with algebraic singularities. Beginning with the Cauchy integral formula, we explicity deform the contour of integration so that it hugs a set of critical points. The asymptotic contribution to the integral comes from analyzing the integrand near these points, leading to explicit asymptotic formulae. Next, we use this formula to analyze an example from current research. In the following chapter, we apply multivariate analytic techniques to quan- tum walks. Bressler and Pemantle (2007) found a (d + 1)-dimensional rational generating function whose coefficients described the amplitude of a particle at a position in the integer lattice after n steps. Here, the minimal critical points form a curve on the (d + 1)-dimensional unit torus. We find asymptotic formulae for the amplitude of a particle in a given position, normalized by the number of steps n, as n approaches infinity. Each critical point contributes to the asymptotics for a specific normalized position. Using Groebner bases in Maple again, we compute the explicit locations of peak amplitudes. In a scaling window of size the square root of n near the peaks, each amplitude is asymptotic to an Airy function.

  5. Asymptotic expansions for high-contrast linear elasticity

    KAUST Repository

    Poveda, Leonardo A.; Huepo, Sebastian; Calo, Victor M.; Galvis, Juan

    2015-01-01

    We study linear elasticity problems with high contrast in the coefficients using asymptotic limits recently introduced. We derive an asymptotic expansion to solve heterogeneous elasticity problems in terms of the contrast in the coefficients. We study the convergence of the expansion in the H1 norm. © 2015 Elsevier B.V.

  6. Asymptotic expansions for high-contrast linear elasticity

    KAUST Repository

    Poveda, Leonardo A.

    2015-03-01

    We study linear elasticity problems with high contrast in the coefficients using asymptotic limits recently introduced. We derive an asymptotic expansion to solve heterogeneous elasticity problems in terms of the contrast in the coefficients. We study the convergence of the expansion in the H1 norm. © 2015 Elsevier B.V.

  7. On asymptotic analysis of spectral problems in elasticity

    Directory of Open Access Journals (Sweden)

    S.A. Nazarov

    Full Text Available The three-dimensional spectral elasticity problem is studied in an anisotropic and inhomogeneous solid with small defects, i.e., inclusions, voids, and microcracks. Asymptotics of eigenfrequencies and the corresponding elastic eigenmodes are constructed and justified. New technicalities of the asymptotic analysis are related to variable coefficients of differential operators, vectorial setting of the problem, and usage of intrinsic integral characteristics of defects. The asymptotic formulae are developed in a form convenient for application in shape optimization and inverse problems.

  8. Endo- vs. exogenous shocks and relaxation rates in book and music “sales”

    Science.gov (United States)

    Lambiotte, R.; Ausloos, M.

    2006-04-01

    In this paper, we analyse the response of music and book sales to an external field and a buyer herding. We distinguish endogenous and exogenous shocks. We focus on some case studies, whose data have been collected from ranking on amazon.com. We show that an ensemble of equivalent systems quantitatively respond in a same way to a similar “external shock”, indicating roads to universality features. In contrast to Sornette et al. [Phys. Rev. Lett. 93 (2004) 228701] who seemed to find power-law behaviours, in particular at long times, a law interpreted in terms of an epidemic activity, we observe that the relaxation process can be as well seen as an exponential one that saturates toward an asymptotic state, itself different from the pre-shock state. By studying an ensemble of 111 shocks, on books or records, we show that exogenous and endogenous shocks are discriminated by their short-time behaviour: the relaxation time seems to be twice shorter in endogenous shocks than in exogenous ones. We interpret the finding through a simple thermodynamic model with a dissipative force.

  9. Asymptotic integration of a linear fourth order differential equation of Poincaré type

    Directory of Open Access Journals (Sweden)

    Anibal Coronel

    2015-11-01

    Full Text Available This article deals with the asymptotic behavior of nonoscillatory solutions of fourth order linear differential equation where the coefficients are perturbations of constants. We define a change of variable and deduce that the new variable satisfies a third order nonlinear differential equation. We assume three hypotheses. The first hypothesis is related to the constant coefficients and set up that the characteristic polynomial associated with the fourth order linear equation has simple and real roots. The other two hypotheses are related to the behavior of the perturbation functions and establish asymptotic integral smallness conditions of the perturbations. Under these general hypotheses, we obtain four main results. The first two results are related to the application of a fixed point argument to prove that the nonlinear third order equation has a unique solution. The next result concerns with the asymptotic behavior of the solutions of the nonlinear third order equation. The fourth main theorem is introduced to establish the existence of a fundamental system of solutions and to precise the formulas for the asymptotic behavior of the linear fourth order differential equation. In addition, we present an example to show that the results introduced in this paper can be applied in situations where the assumptions of some classical theorems are not satisfied.

  10. Bounds and asymptotics for orthogonal polynomials for varying weights

    CERN Document Server

    Levin, Eli

    2018-01-01

    This book establishes bounds and asymptotics under almost minimal conditions on the varying weights, and applies them to universality limits and entropy integrals.  Orthogonal polynomials associated with varying weights play a key role in analyzing random matrices and other topics.  This book will be of use to a wide community of mathematicians, physicists, and statisticians dealing with techniques of potential theory, orthogonal polynomials, approximation theory, as well as random matrices. .

  11. Effects of the aging temperature and stress relaxation conditions on γ′ precipitation in Inconel X-750

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Jeong Won [Department of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Research and Development Center, KOS Limited, Yangsan 626-230 (Korea, Republic of); Seong, Baek Seok [Neutron Science Division, HANARO Center, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Jeong, Hi Won [Advanced Metallic Materials Division, Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Choi, Yoon Suk [Department of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Kang, Namhyun, E-mail: nhkang@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2015-02-15

    Highlights: • Stress relaxation after aging 620 °C increased carbides and maintained γ′ fraction. • Aging temperature increase to 732 °C raised the γ′ increment after stress relaxation. • Small increase of carbides induced the large increase of γ′ after stress relaxation. • Loading for stress relaxation raised γ′ increment due to dislocation multiplication. - Abstract: Inconel X-750 is a Ni-based precipitation-hardened superalloy typically used in springs designed for high-temperature applications such as the hold-down springs in nuclear power plants. γ′ is a major precipitate in X-750 alloys which affects the strength, creep resistance, and stress relaxation properties of the spring. In this study, a solution-treated X-750 wire coiled into a spring was used that was aged at various temperatures and submitted to stress relaxation tests with and without loading. Small angle neutron scattering was employed to quantify the size and volume fraction of γ′ phase in the springs as a function of the aging temperature and the application of a load during stress relaxation. The volume fraction of γ′ precipitates increased in the specimen aged at 732 °C following stress relaxation at 500 °C for 300 h. However, the mean size of the precipitates in the samples was not affected by stress relaxation. The specimen aged at the lower temperature (620 °C) contained a smaller γ′ volume fraction and gained a smaller fraction of γ′ during stress relaxation compared with the sample aged at the higher temperature (732 °C). The smaller increase in the γ′ volume fraction for the sample aged at 620 °C was associated with a larger increase in the M{sub 23}C{sub 6} secondary carbide content during relaxation. The Cr depletion zone around the secondary carbides raises the solubility of γ′ thereby decreasing the volume fraction of γ′ precipitates in Inconel X-750. In terms of stress relaxation, a larger increase in the γ′ volume fraction was

  12. Boundedness, Mittag-Leffler stability and asymptotical ω-periodicity of fractional-order fuzzy neural networks.

    Science.gov (United States)

    Wu, Ailong; Zeng, Zhigang

    2016-02-01

    We show that the ω-periodic fractional-order fuzzy neural networks cannot generate non-constant ω-periodic signals. In addition, several sufficient conditions are obtained to ascertain the boundedness and global Mittag-Leffler stability of fractional-order fuzzy neural networks. Furthermore, S-asymptotical ω-periodicity and global asymptotical ω-periodicity of fractional-order fuzzy neural networks is also characterized. The obtained criteria improve and extend the existing related results. To illustrate and compare the theoretical criteria, some numerical examples with simulation results are discussed in detail. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  13. Asymptotically free SU(5) models

    International Nuclear Information System (INIS)

    Kogan, Ya.I.; Ter-Martirosyan, K.A.; Zhelonkin, A.V.

    1981-01-01

    The behaviour of Yukawa and Higgs effective charges of the minimal SU(5) unification model is investigated. The model includes ν=3 (or more, up to ν=7) generations of quarks and leptons and, in addition, the 24-plet of heavy fermions. A number of solutions of the renorm-group equations are found, which reproduce the known data about quarks and leptons and, due to a special choice of the coupling constants at the unification point are asymptotically free in all charges. The requirement of the asymptotical freedom leads to some restrictions on the masses of particles and on their mixing angles [ru

  14. 8. Asymptotically Flat and Regular Cauchy Data

    Science.gov (United States)

    Dain, Sergio

    I describe the construction of a large class of asymptotically flat initial data with non-vanishing mass and angular momentum for which the metric and the extrinsic curvature have asymptotic expansions at space-like infinity in terms of powers of a radial coordinate. I emphasize the motivations and the main ideas behind the proofs.

  15. Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics

    Science.gov (United States)

    Dewar, R. L.; Yoshida, Z.; Bhattacharjee, A.; Hudson, S. R.

    2015-12-01

    > Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor relaxation model for formation of macroscopically self-organized plasma equilibrium states, all these constraints are relaxed save for the global magnetic fluxes and helicity. A Lagrangian variational principle is presented that leads to a new, fully dynamical, relaxed magnetohydrodynamics (RxMHD), such that all static solutions are Taylor states but also allows state with flow. By postulating that some long-lived macroscopic current sheets can act as barriers to relaxation, separating the plasma into multiple relaxation regions, a further generalization, multi-region relaxed magnetohydrodynamics (MRxMHD) is developed.

  16. Asymptotics for the Kummer function of Bose plasmas

    International Nuclear Information System (INIS)

    Kowalenko, V.; Frankel, N.E.

    1993-01-01

    The asymptotic expansions for the Kummer function obtained in the study of the linear response of magnetised Bose plasmas at T = 0 K are presented for large and small values of its parameter, thereby displaying the function's asymptotic non-uniformity. The large parameter expansion plays a determining role in the behaviour of these Bose systems in the limit that the external magnetic field B →0. This particular expansion is generalised herein and its validity tested by determining the asymptotic expansion for the Hurwitz zeta function. 18 refs., 1 tab., 2 figs

  17. Optimal relaxed causal sampler using sampled-date system theory

    NARCIS (Netherlands)

    Shekhawat, Hanumant; Meinsma, Gjerrit

    This paper studies the design of an optimal relaxed causal sampler using sampled data system theory. A lifted frequency domain approach is used to obtain the existence conditions and the optimal sampler. A state space formulation of the results is also provided. The resulting optimal relaxed causal

  18. Preheating in an asymptotically safe quantum field theory

    DEFF Research Database (Denmark)

    Svendsen, Ole; Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-01-01

    . High Energy Phys. 01 (2016) 081]. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period of reheating. Since the models contain many scalar fields which are intrinsically coupled to the inflaton there is the possibility of parametric resonance...... fluctuations induced by the parametrically amplified entropy modes do not exceed the upper observational bounds puts a lower bound on the number of fields which the model followed in [D. F. Litim and F. Sannino, Asymptotic safety guaranteed, J. High Energy Phys. 12 (2014) 178; D. F. Litim, M. Mojaza, and F......We consider reheating in a class of asymptotically safe quantum field theories recently studied in [D. F. Litim and F. Sannino, Asymptotic safety guaranteed, J. High Energy Phys. 12 (2014) 178; D. F. Litim, M. Mojaza, and F. Sannino, Vacuum stability of asymptotically safe gauge-Yukawa theories, J...

  19. A method for summing nonalternating asymptotic series

    International Nuclear Information System (INIS)

    Kazakov, D.I.

    1980-01-01

    A method for reconstructing a function from its nonalternating asymptotic series is proposed. It can also be applied when only a limited number of coefficients and their high order asymptotic behaviour are known. The method is illustrated by examples of the ordinary simple integral simulating a functional integral in a theory with degenerate minimum and of the double-well unharmonic oscillator

  20. Asymptotic Analysis in MIMO MRT/MRC Systems

    Directory of Open Access Journals (Sweden)

    Zhou Quan

    2006-01-01

    Full Text Available Through the analysis of the probability density function of the squared largest singular value of a complex Gaussian matrix at the origin and tail, we obtain two asymptotic results related to the multi-input multi-output (MIMO maximum-ratio-transmission/maximum-ratio-combining (MRT/MRC systems. One is the asymptotic error performance (in terms of SNR in a single-user system, and the other is the asymptotic system capacity (in terms of the number of users in the multiuser scenario when multiuser diversity is exploited. Similar results are also obtained for two other MIMO diversity schemes, space-time block coding and selection combining. Our results reveal a simple connection with system parameters, providing good insights for the design of MIMO diversity systems.

  1. The Data-Constrained Generalized Maximum Entropy Estimator of the GLM: Asymptotic Theory and Inference

    Directory of Open Access Journals (Sweden)

    Nicholas Scott Cardell

    2013-05-01

    Full Text Available Maximum entropy methods of parameter estimation are appealing because they impose no additional structure on the data, other than that explicitly assumed by the analyst. In this paper we prove that the data constrained GME estimator of the general linear model is consistent and asymptotically normal. The approach we take in establishing the asymptotic properties concomitantly identifies a new computationally efficient method for calculating GME estimates. Formulae are developed to compute asymptotic variances and to perform Wald, likelihood ratio, and Lagrangian multiplier statistical tests on model parameters. Monte Carlo simulations are provided to assess the performance of the GME estimator in both large and small sample situations. Furthermore, we extend our results to maximum cross-entropy estimators and indicate a variant of the GME estimator that is unbiased. Finally, we discuss the relationship of GME estimators to Bayesian estimators, pointing out the conditions under which an unbiased GME estimator would be efficient.

  2. Global Asymptotic Stability of Impulsive CNNs with Proportional Delays and Partially Lipschitz Activation Functions

    Directory of Open Access Journals (Sweden)

    Xueli Song

    2014-01-01

    Full Text Available This paper researches global asymptotic stability of impulsive cellular neural networks with proportional delays and partially Lipschitz activation functions. Firstly, by means of the transformation vi(t=ui(et, the impulsive cellular neural networks with proportional delays are transformed into impulsive cellular neural networks with the variable coefficients and constant delays. Secondly, we provide novel criteria for the uniqueness and exponential stability of the equilibrium point of the latter by relative nonlinear measure and prove that the exponential stability of equilibrium point of the latter implies the asymptotic stability of one of the former. We furthermore obtain a sufficient condition to the uniqueness and global asymptotic stability of the equilibrium point of the former. Our method does not require conventional assumptions on global Lipschitz continuity, boundedness, and monotonicity of activation functions. Our results are generalizations and improvements of some existing ones. Finally, an example and its simulations are provided to illustrate the correctness of our analysis.

  3. Temperature relaxation in collisional non equilibrium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Potapenko, I.F.; Bobylev, A.V.; Azevedo, C.A.; Assis, A.S. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

    1997-12-31

    Full text. We study the relaxation of a space uniform plasma composed of electrons and one species of ions. To simplified the consideration, standard approach is usually accepted: the distribution functions are considered to be a Maxwellian with time dependent electron T{sub e}(t) and ion T{sub i}(t) temperatures. This approach imposes a severe restriction on the electron/ion distributions that could be very far from the equilibrium. In the present work the problem is investigated on the basis of the nonlinear kinetic Fokker - Planck equation, which is widely used for the description of collisional plasmas. This equation has many applications in plasma physics as an intrinsic part of physical models, both analytical and numerical. A new detailed description of this classical problem of the collisional plasma kinetic theory is given. A deeper examination of the problem shows that the unusual perturbation theory can not be used. The part of the perturbation of the electron distribution has the character of a boundary layer in the neighborhood of small velocities. In this work the boundary layer is thoroughly studied. The correct distribution electron function is given. Nonmonotonic character of the distribution relaxation in the tail region is observed. The corrected formula for temperature equalization is obtained. The comparison of the calculation results with the asymptotic approach is made. We should stress the important role of the completely conservative different scheme used here, which keeps the symmetric properties of the nonlinear exact equation. This allows us to make calculations without numerical error accumulations, except for machine errors. (author)

  4. Impulsive effects on global asymptotic stability of delay BAM neural networks

    International Nuclear Information System (INIS)

    Chen Jun; Cui Baotong

    2008-01-01

    Based on the proper Lyapunov functions and the Jacobsthal liner inequality, some sufficient conditions are presented in this paper for global asymptotic stability of delay bidirectional associative memory neural networks with impulses. The obtained results are independently of the delay parameters and can be easily verified. Also, some remarks and an illustrative example are given to demonstrate the effectiveness of the obtained results

  5. Asymptotic failure rate of a continuously monitored system

    International Nuclear Information System (INIS)

    Grall, A.; Dieulle, L.; Berenguer, C.; Roussignol, M.

    2006-01-01

    This paper deals with a perfectly continuously monitored system which gradually and stochastically deteriorates. The system is renewed by a delayed maintenance operation, which is triggered when the measured deterioration level exceeds an alarm threshold. A mathematical model is developed to study the asymptotic behavior of the reliability function. A procedure is proposed which allows us to identify the asymptotic failure rate of the maintained system. Numerical experiments illustrate the efficiency of the proposed procedure and emphasize the relevance of the asymptotic failure rate as an interesting indicator for the evaluation of the control-limit preventive replacement policy

  6. Asymptotic failure rate of a continuously monitored system

    Energy Technology Data Exchange (ETDEWEB)

    Grall, A. [Institut des Sciences et Technologies de l' Information de Troyes (CNRS-FRE 2732), Equipe de Modelisation et de Surete des Systemes, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France)]. E-mail: antoine.grall@utt.fr; Dieulle, L. [Institut des Sciences et Technologies de l' Information de Troyes (CNRS-FRE 2732), Equipe de Modelisation et de Surete des Systemes, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France)]. E-mail: laurence.dieulle@utt.fr; Berenguer, C. [Institut des Sciences et Technologies de l' Information de Troyes (CNRS-FRE 2732), Equipe de Modelisation et de Surete des Systemes, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France)]. E-mail: christophe.berenguer@utt.fr; Roussignol, M. [Laboratoire d' Analyse et de Mathematiques Appliquees, Universite de Marne la Vallee, 5 bd Descartes, Champs sur Marne, 77454 Marne la Vallee, Cedex 2 (France)]. E-mail: michel.roussignol@univ-mlv.fr

    2006-02-01

    This paper deals with a perfectly continuously monitored system which gradually and stochastically deteriorates. The system is renewed by a delayed maintenance operation, which is triggered when the measured deterioration level exceeds an alarm threshold. A mathematical model is developed to study the asymptotic behavior of the reliability function. A procedure is proposed which allows us to identify the asymptotic failure rate of the maintained system. Numerical experiments illustrate the efficiency of the proposed procedure and emphasize the relevance of the asymptotic failure rate as an interesting indicator for the evaluation of the control-limit preventive replacement policy.

  7. Symmetry breaking and asymptotic freedom in colour SU(3) gauge models

    International Nuclear Information System (INIS)

    Ma, E.

    1976-01-01

    A class of quark models based on the colour gauge group SU(3) is shown to be asymptotically free despite the complete breakdown of local symmetry to guarantee infrared stability. The symmetry breakdown is achieved by the presence of elementary scalar fields either through the Higgs mechanism or dynamically as first proposed by Coleman and Weinberg. Asymptotic freedom is preserved by imposing eigenvalue conditions on the coupling constants as first proposed by Chang. New quark species must be present, but below their production threshold, colour can still be a global symmetry which is approximate under SU(3), but exact under SU(2). Among the many implications of this class of models is the possibility of producing isolated quarks and gluons of non-zero mass without altering the short-distance behaviour of the superstrong interaction which binds them. (Auth.)

  8. Comment on 'Asymptotic form of the Kohn-Sham correlation potential'

    International Nuclear Information System (INIS)

    Holas, A.

    2008-01-01

    For finite systems that have the energetically highest-occupied molecular orbital (HOMO) with an asymptotic nodal surface, Joubert demonstrated recently [Phys. Rev. A 76, 012501 (2007)] strongly anisotropic behavior (in the asymptotic large-r region) of the exact correlation potential of density-functional theory. As is shown by us, this result is a direct and simple consequence of the strong anisotropy of the exact exchange potential obtained by Della Sala and Goerling [Phys. Rev. Lett. 89, 033003 (2002); Della Sala and GoerlingJ. Chem. Phys. 116, 5374 (2002)] and the assumption about the asymptotic isotropy of the Kohn-Sham (KS) potential (based on the investigation of Almbladh and von Barth [Phys. Rev. B 31, 3231 (1985)] for atoms). Joubert's result remains a hypothesis only, because the last assumption is in contradiction with the asymptotic strong anisotropy of the KS potential for systems with asymptotic nodal surface of the HOMO, demonstrated by Wu, Ayers, and Yang [J. Chem. Phys. 119, 2978 (2003)]. The correlation potential in the asymptotic region, stemming from their results, is given

  9. A general framework for global asymptotic stability analysis of delayed neural networks based on LMI approach

    International Nuclear Information System (INIS)

    Cao Jinde; Ho, Daniel W.C.

    2005-01-01

    In this paper, global asymptotic stability is discussed for neural networks with time-varying delay. Several new criteria in matrix inequality form are given to ascertain the uniqueness and global asymptotic stability of equilibrium point for neural networks with time-varying delay based on Lyapunov method and Linear Matrix Inequality (LMI) technique. The proposed LMI approach has the advantage of considering the difference of neuronal excitatory and inhibitory efforts, which is also computationally efficient as it can be solved numerically using recently developed interior-point algorithm. In addition, the proposed results generalize and improve previous works. The obtained criteria also combine two existing conditions into one generalized condition in matrix form. An illustrative example is also given to demonstrate the effectiveness of the proposed results

  10. Pseudo-random number generator based on asymptotic deterministic randomness

    Science.gov (United States)

    Wang, Kai; Pei, Wenjiang; Xia, Haishan; Cheung, Yiu-ming

    2008-06-01

    A novel approach to generate the pseudorandom-bit sequence from the asymptotic deterministic randomness system is proposed in this Letter. We study the characteristic of multi-value correspondence of the asymptotic deterministic randomness constructed by the piecewise linear map and the noninvertible nonlinearity transform, and then give the discretized systems in the finite digitized state space. The statistic characteristics of the asymptotic deterministic randomness are investigated numerically, such as stationary probability density function and random-like behavior. Furthermore, we analyze the dynamics of the symbolic sequence. Both theoretical and experimental results show that the symbolic sequence of the asymptotic deterministic randomness possesses very good cryptographic properties, which improve the security of chaos based PRBGs and increase the resistance against entropy attacks and symbolic dynamics attacks.

  11. Pseudo-random number generator based on asymptotic deterministic randomness

    International Nuclear Information System (INIS)

    Wang Kai; Pei Wenjiang; Xia Haishan; Cheung Yiuming

    2008-01-01

    A novel approach to generate the pseudorandom-bit sequence from the asymptotic deterministic randomness system is proposed in this Letter. We study the characteristic of multi-value correspondence of the asymptotic deterministic randomness constructed by the piecewise linear map and the noninvertible nonlinearity transform, and then give the discretized systems in the finite digitized state space. The statistic characteristics of the asymptotic deterministic randomness are investigated numerically, such as stationary probability density function and random-like behavior. Furthermore, we analyze the dynamics of the symbolic sequence. Both theoretical and experimental results show that the symbolic sequence of the asymptotic deterministic randomness possesses very good cryptographic properties, which improve the security of chaos based PRBGs and increase the resistance against entropy attacks and symbolic dynamics attacks

  12. Numerical algorithms for uniform Airy-type asymptotic expansions

    NARCIS (Netherlands)

    N.M. Temme (Nico)

    1997-01-01

    textabstractAiry-type asymptotic representations of a class of special functions are considered from a numerical point of view. It is well known that the evaluation of the coefficients of the asymptotic series near the transition point is a difficult problem. We discuss two methods for computing

  13. H. David Politzer, Asymptotic Freedom, and Strong Interaction

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis H. David Politzer, Asymptotic Freedom, and Strong Interaction Resources with Additional Information H. David Politzer Photo Credit: California Institute of Technology H. David Politzer has won the 2004 Nobel Prize in Physics 'for the discovery of asymptotic freedom

  14. Robust methods and asymptotic theory in nonlinear econometrics

    CERN Document Server

    Bierens, Herman J

    1981-01-01

    This Lecture Note deals with asymptotic properties, i.e. weak and strong consistency and asymptotic normality, of parameter estimators of nonlinear regression models and nonlinear structural equations under various assumptions on the distribution of the data. The estimation methods involved are nonlinear least squares estimation (NLLSE), nonlinear robust M-estimation (NLRME) and non­ linear weighted robust M-estimation (NLWRME) for the regression case and nonlinear two-stage least squares estimation (NL2SLSE) and a new method called minimum information estimation (MIE) for the case of structural equations. The asymptotic properties of the NLLSE and the two robust M-estimation methods are derived from further elaborations of results of Jennrich. Special attention is payed to the comparison of the asymptotic efficiency of NLLSE and NLRME. It is shown that if the tails of the error distribution are fatter than those of the normal distribution NLRME is more efficient than NLLSE. The NLWRME method is appropriate ...

  15. Stark resonances: asymptotics and distributional Borel sum

    International Nuclear Information System (INIS)

    Caliceti, E.; Grecchi, V.; Maioli, M.

    1993-01-01

    We prove that the Stark effect perturbation theory of a class of bound states uniquely determines the position and the width of the resonances by Distributional Borel Sum. In particular the small field asymptotics of the width is uniquely related to the large order asymptotics of the perturbation coefficients. Similar results apply to all the ''resonances'' of the anharmonic and double well oscillators. (orig.)

  16. Oscillation and asymptotic stability of a delay differential equation with Richard's nonlinearity

    Directory of Open Access Journals (Sweden)

    Leonid Berezansky

    2005-04-01

    Full Text Available We obtain sufficient conditions for oscillation of solutions, and for asymptotical stability of the positive equilibrium, of the scalar nonlinear delay differential equation $$ frac{dN}{dt} = r(tN(tBig[a-Big(sum_{k=1}^m b_k N(g_k(tBig^{gamma}Big], $$ where $ g_k(tleq t$.

  17. Global asymptotic stability of bistable traveling fronts in reaction-diffusion systems and their applications to biological models

    International Nuclear Information System (INIS)

    Wu Shiliang; Li Wantong

    2009-01-01

    This paper deals with the global asymptotic stability and uniqueness (up to translation) of bistable traveling fronts in a class of reaction-diffusion systems. The known results do not apply in solving these problems because the reaction terms do not satisfy the required monotone condition. To overcome the difficulty, a weak monotone condition is proposed for the reaction terms, which is called interval monotone condition. Under such a weak monotone condition, the existence and comparison theorem of solutions is first established for reaction-diffusion systems on R by appealing to the theory of abstract differential equations. The global asymptotic stability and uniqueness (up to translation) of bistable traveling fronts are then proved by the elementary super- and sub-solution comparison and squeezing methods for nonlinear evolution equations. Finally, these abstract results are applied to a two species competition-diffusion model and a system modeling man-environment-man epidemics.

  18. Effects of relaxation on psychobiological wellbeing during pregnancy: a randomized controlled trial.

    Science.gov (United States)

    Urech, Corinne; Fink, Nadine S; Hoesli, Irène; Wilhelm, Frank H; Bitzer, Johannes; Alder, Judith

    2010-10-01

    Prenatal maternal stress is associated with adverse birth outcomes and may be reduced by relaxation exercises. The aim of the present study was to compare the immediate effects of two active and one passive 10-min relaxation technique on perceived and physiological indicators of relaxation. 39 healthy pregnant women recruited at the outpatient department of the University Women's Hospital Basel participated in a randomized controlled trial with an experimental repeated measure design. Participants were assigned to one of two active relaxation techniques, progressive muscle relaxation (PMR) or guided imagery (GI), or a passive relaxation control condition. Self-reported relaxation on a visual analogue scale (VAS) and state anxiety (STAI-S), endocrine parameters indicating hypothalamic-pituitary-adrenal (HPA) axis (cortisol and ACTH) and sympathetic-adrenal-medullary (SAM) system activity (norepinephrine and epinephrine), as well as cardiovascular responses (heart rate, systolic and diastolic blood pressure) were measured at four time points before and after the relaxation exercise. Between group differences showed, that compared to the PMR and control conditions, GI was significantly more effective in enhancing levels of relaxation and together with PMR, GI was associated with a significant decrease in heart rate. Within the groups, passive as well as active relaxation procedures were associated with a decline in endocrine measures except epinephrine. Taken together, these data indicate that different types of relaxation had differential effects on various psychological and biological stress systems. GI was especially effective in inducing self-reported relaxation in pregnant women while at the same time reducing cardiovascular activity. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Dynamic Mesh Adaptation for Front Evolution Using Discontinuous Galerkin Based Weighted Condition Number Mesh Relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schofield, Samuel P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-06-21

    A new mesh smoothing method designed to cluster mesh cells near a dynamically evolving interface is presented. The method is based on weighted condition number mesh relaxation with the weight function being computed from a level set representation of the interface. The weight function is expressed as a Taylor series based discontinuous Galerkin projection, which makes the computation of the derivatives of the weight function needed during the condition number optimization process a trivial matter. For cases when a level set is not available, a fast method for generating a low-order level set from discrete cell-centered elds, such as a volume fraction or index function, is provided. Results show that the low-order level set works equally well for the weight function as the actual level set. Meshes generated for a number of interface geometries are presented, including cases with multiple level sets. Dynamic cases for moving interfaces are presented to demonstrate the method's potential usefulness to arbitrary Lagrangian Eulerian (ALE) methods.

  20. Asymptotic freedom without guilt

    International Nuclear Information System (INIS)

    Ma, E.

    1979-01-01

    The notion of asymptotic freedom in quantum chromodynamics is explained on general physical grounds, without invoking the formal arguments of renormalizable quantum field theory. The related concept of quark confinement is also discussed along the same line. 5 references

  1. Behavior of asymptotically electro-Λ spacetimes

    Science.gov (United States)

    Saw, Vee-Liem

    2017-04-01

    We present the asymptotic solutions for spacetimes with nonzero cosmological constant Λ coupled to Maxwell fields, using the Newman-Penrose formalism. This extends a recent work that dealt with the vacuum Einstein (Newman-Penrose) equations with Λ ≠0 . The results are given in two different null tetrads: the Newman-Unti and Szabados-Tod null tetrads, where the peeling property is exhibited in the former but not the latter. Using these asymptotic solutions, we discuss the mass loss of an isolated electrogravitating system with cosmological constant. In a universe with Λ >0 , the physics of electromagnetic (EM) radiation is relatively straightforward compared to those of gravitational radiation: (1) It is clear that outgoing EM radiation results in a decrease to the Bondi mass of the isolated system. (2) It is also perspicuous that if any incoming EM radiation from elsewhere is present, those beyond the isolated system's cosmological horizon would eventually arrive at the spacelike I and increase the Bondi mass of the isolated system. Hence, the (outgoing and incoming) EM radiation fields do not couple with Λ in the Bondi mass-loss formula in an unusual manner, unlike the gravitational counterpart where outgoing gravitational radiation induces nonconformal flatness of I . These asymptotic solutions to the Einstein-Maxwell-de Sitter equations presented here may be used to extend a raft of existing results based on Newman-Unti's asymptotic solutions to the Einstein-Maxwell equations where Λ =0 , to now incorporate the cosmological constant Λ .

  2. Numerical integration of asymptotic solutions of ordinary differential equations

    Science.gov (United States)

    Thurston, Gaylen A.

    1989-01-01

    Classical asymptotic analysis of ordinary differential equations derives approximate solutions that are numerically stable. However, the analysis also leads to tedious expansions in powers of the relevant parameter for a particular problem. The expansions are replaced with integrals that can be evaluated by numerical integration. The resulting numerical solutions retain the linear independence that is the main advantage of asymptotic solutions. Examples, including the Falkner-Skan equation from laminar boundary layer theory, illustrate the method of asymptotic analysis with numerical integration.

  3. Exact asymptotic expansions for solutions of multi-dimensional renewal equations

    International Nuclear Information System (INIS)

    Sgibnev, M S

    2006-01-01

    We derive expansions with exact asymptotic expressions for the remainders for solutions of multi-dimensional renewal equations. The effect of the roots of the characteristic equation on the asymptotic representation of solutions is taken into account. The resulting formulae are used to investigate the asymptotic behaviour of the average number of particles in age-dependent branching processes having several types of particles

  4. Asymptotic stability of a catalyst particle

    DEFF Research Database (Denmark)

    Wedel, Stig; Michelsen, Michael L.; Villadsen, John

    1977-01-01

    The catalyst asymptotic stability problem is studied by means of several new methods that allow accurate solutions to be calculated where other methods have given qualitatively erroneous results. The underlying eigenvalue problem is considered in three limiting situations Le = ∞, 1 and 0. These a......The catalyst asymptotic stability problem is studied by means of several new methods that allow accurate solutions to be calculated where other methods have given qualitatively erroneous results. The underlying eigenvalue problem is considered in three limiting situations Le = ∞, 1 and 0...

  5. On extracting physical content from asymptotically flat spacetime metrics

    International Nuclear Information System (INIS)

    Kozameh, C; Newman, E T; Silva-Ortigoza, G

    2008-01-01

    A major issue in general relativity, from its earliest days to the present, is how to extract physical information from any solution or class of solutions to the Einstein equations. Though certain information can be obtained for arbitrary solutions, e.g., via geodesic deviation, in general, because of the coordinate freedom, it is often hard or impossible to do. Most of the time information is found from special conditions, e.g. degenerate principle null vectors, weak fields close to Minkowski space (using coordinates close to Minkowski coordinates), or from solutions that have symmetries or approximate symmetries. In the present work, we will be concerned with asymptotically flat spacetimes where the approximate symmetry is the Bondi-Metzner-Sachs group. For these spaces the Bondi 4-momentum vector and its evolution, found from the Weyl tensor at infinity, describes the total energy-momentum of the interior source and the energy-momentum radiated. By generalizing the structures (shear-free null geodesic congruences) associated with the algebraically special metrics to asymptotically shear-free null geodesic congruences, which are available in all asymptotically flat spacetimes, we give kinematic meaning to the Bondi 4-momentum. In other words, we describe the Bondi vector and its evolution in terms of a center of mass position vector, its velocity and a spin vector, all having clear geometric meaning. Among other items, from dynamic arguments, we define a unique (at our level of approximation) total angular momentum and extract its evolution equation in the form of a conservation law with an angular momentum flux

  6. Non-Asymptotic Confidence Sets for Circular Means

    Directory of Open Access Journals (Sweden)

    Thomas Hotz

    2016-10-01

    Full Text Available The mean of data on the unit circle is defined as the minimizer of the average squared Euclidean distance to the data. Based on Hoeffding’s mass concentration inequalities, non-asymptotic confidence sets for circular means are constructed which are universal in the sense that they require no distributional assumptions. These are then compared with asymptotic confidence sets in simulations and for a real data set.

  7. Global asymptotic stability of Cohen-Grossberg neural network with continuously distributed delays

    International Nuclear Information System (INIS)

    Wan Li; Sun Jianhua

    2005-01-01

    The convergence dynamical behaviors of Cohen-Grossberg neural network with continuously distributed delays are discussed. By using Brouwer's fixed point theorem, matrix theory and analysis techniques such as Gronwall inequality, some new sufficient conditions guaranteeing the existence, uniqueness of an equilibrium point and its global asymptotic stability are obtained. An example is given to illustrate the theoretical results

  8. Asymptotic freedom

    International Nuclear Information System (INIS)

    Meyer, P.

    1978-01-01

    After having established the renormalization group equations and the possibilities of fixed points for the effective coupling constants the non abelian gauge theories are shown to have the property of asymptotic freedom. These results are applied to the colour gauge group of the strong interactions of quarks and gluons. The behavior of the moments of the structure functions of the deep inelastic scattering of leptons on nucleons (scaling and its logarithmic violations) is then deduced with using the Wilson's operator product expansion [fr

  9. On conformal-invariant behaviour of four-point theories in ultraviolet asymptotics

    International Nuclear Information System (INIS)

    Ushveridze, A.G.

    1977-01-01

    A method is presented to obtain scale- and conformal-invariant solutions of four-point field theories in the ultraviolet asymptotics by means of reduction to the three-point problem. To do this a supplementary sigma field without a kinetic term is introduced and the Lagrangian is modified correspondingly. For the three-point problems the equations in form of the generalized unitarity conditions are solved further

  10. Cookbook asymptotics for spiral and scroll waves in excitable media.

    Science.gov (United States)

    Margerit, Daniel; Barkley, Dwight

    2002-09-01

    Algebraic formulas predicting the frequencies and shapes of waves in a reaction-diffusion model of excitable media are presented in the form of four recipes. The formulas themselves are based on a detailed asymptotic analysis (published elsewhere) of the model equations at leading order and first order in the asymptotic parameter. The importance of the first order contribution is stressed throughout, beginning with a discussion of the Fife limit, Fife scaling, and Fife regime. Recipes are given for spiral waves and detailed comparisons are presented between the asymptotic predictions and the solutions of the full reaction-diffusion equations. Recipes for twisted scroll waves with straight filaments are given and again comparisons are shown. The connection between the asymptotic results and filament dynamics is discussed, and one of the previously unknown coefficients in the theory of filament dynamics is evaluated in terms of its asymptotic expansion. (c) 2002 American Institute of Physics.

  11. Semi-parametric estimation for ARCH models

    Directory of Open Access Journals (Sweden)

    Raed Alzghool

    2018-03-01

    Full Text Available In this paper, we conduct semi-parametric estimation for autoregressive conditional heteroscedasticity (ARCH model with Quasi likelihood (QL and Asymptotic Quasi-likelihood (AQL estimation methods. The QL approach relaxes the distributional assumptions of ARCH processes. The AQL technique is obtained from the QL method when the process conditional variance is unknown. We present an application of the methods to a daily exchange rate series. Keywords: ARCH model, Quasi likelihood (QL, Asymptotic Quasi-likelihood (AQL, Martingale difference, Kernel estimator

  12. A relaxation-projection method for compressible flows. Part II: Artificial heat exchanges for multiphase shocks

    International Nuclear Information System (INIS)

    Petitpas, Fabien; Franquet, Erwin; Saurel, Richard; Le Metayer, Olivier

    2007-01-01

    The relaxation-projection method developed in Saurel et al. [R. Saurel, E. Franquet, E. Daniel, O. Le Metayer, A relaxation-projection method for compressible flows. Part I: The numerical equation of state for the Euler equations, J. Comput. Phys. (2007) 822-845] is extended to the non-conservative hyperbolic multiphase flow model of Kapila et al. [A.K. Kapila, Menikoff, J.B. Bdzil, S.F. Son, D.S. Stewart, Two-phase modeling of deflagration to detonation transition in granular materials: reduced equations, Physics of Fluids 13(10) (2001) 3002-3024]. This model has the ability to treat multi-temperatures mixtures evolving with a single pressure and velocity and is particularly interesting for the computation of interface problems with compressible materials as well as wave propagation in heterogeneous mixtures. The non-conservative character of this model poses however computational challenges in the presence of shocks. The first issue is related to the Riemann problem resolution that necessitates shock jump conditions. Thanks to the Rankine-Hugoniot relations proposed and validated in Saurel et al. [R. Saurel, O. Le Metayer, J. Massoni, S. Gavrilyuk, Shock jump conditions for multiphase mixtures with stiff mechanical relaxation, Shock Waves 16 (3) (2007) 209-232] exact and approximate 2-shocks Riemann solvers are derived. However, the Riemann solver is only a part of a numerical scheme and non-conservative variables pose extra difficulties for the projection or cell average of the solution. It is shown that conventional Godunov schemes are unable to converge to the exact solution for strong multiphase shocks. This is due to the incorrect partition of the energies or entropies in the cell averaged mixture. To circumvent this difficulty a specific Lagrangian scheme is developed. The correct partition of the energies is achieved by using an artificial heat exchange in the shock layer. With the help of an asymptotic analysis this heat exchange takes a similar form as

  13. A relaxation-projection method for compressible flows. Part II: Artificial heat exchanges for multiphase shocks

    Science.gov (United States)

    Petitpas, Fabien; Franquet, Erwin; Saurel, Richard; Le Metayer, Olivier

    2007-08-01

    The relaxation-projection method developed in Saurel et al. [R. Saurel, E. Franquet, E. Daniel, O. Le Metayer, A relaxation-projection method for compressible flows. Part I: The numerical equation of state for the Euler equations, J. Comput. Phys. (2007) 822-845] is extended to the non-conservative hyperbolic multiphase flow model of Kapila et al. [A.K. Kapila, Menikoff, J.B. Bdzil, S.F. Son, D.S. Stewart, Two-phase modeling of deflagration to detonation transition in granular materials: reduced equations, Physics of Fluids 13(10) (2001) 3002-3024]. This model has the ability to treat multi-temperatures mixtures evolving with a single pressure and velocity and is particularly interesting for the computation of interface problems with compressible materials as well as wave propagation in heterogeneous mixtures. The non-conservative character of this model poses however computational challenges in the presence of shocks. The first issue is related to the Riemann problem resolution that necessitates shock jump conditions. Thanks to the Rankine-Hugoniot relations proposed and validated in Saurel et al. [R. Saurel, O. Le Metayer, J. Massoni, S. Gavrilyuk, Shock jump conditions for multiphase mixtures with stiff mechanical relaxation, Shock Waves 16 (3) (2007) 209-232] exact and approximate 2-shocks Riemann solvers are derived. However, the Riemann solver is only a part of a numerical scheme and non-conservative variables pose extra difficulties for the projection or cell average of the solution. It is shown that conventional Godunov schemes are unable to converge to the exact solution for strong multiphase shocks. This is due to the incorrect partition of the energies or entropies in the cell averaged mixture. To circumvent this difficulty a specific Lagrangian scheme is developed. The correct partition of the energies is achieved by using an artificial heat exchange in the shock layer. With the help of an asymptotic analysis this heat exchange takes a similar form as

  14. From asymptotic safety to dark energy

    International Nuclear Information System (INIS)

    Ahn, Changrim; Kim, Chanju; Linder, Eric V.

    2011-01-01

    We consider renormalization group flow applied to the cosmological dynamical equations. A consistency condition arising from energy-momentum conservation links the flow parameters to the cosmological evolution, restricting possible behaviors. Three classes of cosmological fixed points for dark energy plus a barotropic fluid are found: a dark energy dominated universe, which can be either accelerating or decelerating depending on the RG flow parameters, a barotropic dominated universe where dark energy fades away, and solutions where the gravitational and potential couplings cease to flow. If the IR fixed point coincides with the asymptotically safe UV fixed point then the dark energy pressure vanishes in the first class, while (only) in the de Sitter limit of the third class the RG cutoff scale becomes the Hubble scale.

  15. Asymptotic propagators and trajectories in plasma turbulence theory. The importance of irreversibility, asymptoticity and non-Markovian terms

    International Nuclear Information System (INIS)

    Misguich, J.H.

    1978-09-01

    The physical meaning of perturbed trajectories in turbulent fields is analysed. Special care is devoted to the asymptotic description of average trajectories for long time intervals, as occuring in many recent plasma turbulence theories. Equivalence is proved between asymptotic average trajectories described as well (i) by the propagators V(t,t-tau) for retrodiction and Wsub(J)(t,t+tau) for prediction, and (ii) by the long time secular behavior of the solution of the equations of motion. This confirms the equivalence between perturbed orbit theories and renormalized theories, including non-Markovian contributions

  16. An asymptotical machine

    Science.gov (United States)

    Cristallini, Achille

    2016-07-01

    A new and intriguing machine may be obtained replacing the moving pulley of a gun tackle with a fixed point in the rope. Its most important feature is the asymptotic efficiency. Here we obtain a satisfactory description of this machine by means of vector calculus and elementary trigonometry. The mathematical model has been compared with experimental data and briefly discussed.

  17. Global asymptotic stability of hybrid bidirectional associative memory neural networks with time delays

    International Nuclear Information System (INIS)

    Arik, Sabri

    2006-01-01

    This Letter presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all bounded continuous non-monotonic neuron activation functions. The results are also compared with the previous results derived in the literature

  18. Global asymptotic stability of hybrid bidirectional associative memory neural networks with time delays

    Science.gov (United States)

    Arik, Sabri

    2006-02-01

    This Letter presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all bounded continuous non-monotonic neuron activation functions. The results are also compared with the previous results derived in the literature.

  19. Asymptotic safety of gravity with matter

    Science.gov (United States)

    Christiansen, Nicolai; Litim, Daniel F.; Pawlowski, Jan M.; Reichert, Manuel

    2018-05-01

    We study the asymptotic safety conjecture for quantum gravity in the presence of matter fields. A general line of reasoning is put forward explaining why gravitons dominate the high-energy behavior, largely independently of the matter fields as long as these remain sufficiently weakly coupled. Our considerations are put to work for gravity coupled to Yang-Mills theories with the help of the functional renormalization group. In an expansion about flat backgrounds, explicit results for beta functions, fixed points, universal exponents, and scaling solutions are given in systematic approximations exploiting running propagators, vertices, and background couplings. Invariably, we find that the gauge coupling becomes asymptotically free while the gravitational sector becomes asymptotically safe. The dependence on matter field multiplicities is weak. We also explain how the scheme dependence, which is more pronounced, can be handled without changing the physics. Our findings offer a new interpretation of many earlier results, which is explained in detail. The results generalize to theories with minimally coupled scalar and fermionic matter. Some implications for the ultraviolet closure of the Standard Model or its extensions are given.

  20. Asymptotic series and functional integrals in quantum field theory

    International Nuclear Information System (INIS)

    Shirkov, D.V.

    1979-01-01

    Investigations of the methods for analyzing ultra-violet and infrared asymptotics in the quantum field theory (QFT) have been reviewed. A powerful method of the QFT analysis connected with the group property of renormalized transformations has been created at the first stage. The result of the studies of the second period is the constructive solution of the problem of outgoing the framework of weak coupling. At the third stage of studies essential are the asymptotic series and functional integrals in the QFT, which are used for obtaining the asymptotic type of the power expansion coefficients in the coupling constant at high values of the exponents for a number of simple models. Further advance to higher values of the coupling constant requires surmounting the difficulties resulting from the asymptotic character of expansions and a constructive application in the region of strong coupling (g >> 1)

  1. On parametric domain for asymptotic stability with probability one of zero solution of linear Ito stochastic differential equations

    International Nuclear Information System (INIS)

    Phan Thanh An; Phan Le Na; Ngo Quoc Chung

    2004-05-01

    We describe a practical implementation for finding parametric domain for asymptotic stability with probability one of zero solution of linear Ito stochastic differential equations based on Korenevskij and Mitropolskij's sufficient condition and our sufficient conditions. Numerical results show that all of these sufficient conditions are crucial in the implementation. (author)

  2. Relative efficiency of joint-model and full-conditional-specification multiple imputation when conditional models are compatible: The general location model.

    Science.gov (United States)

    Seaman, Shaun R; Hughes, Rachael A

    2018-06-01

    Estimating the parameters of a regression model of interest is complicated by missing data on the variables in that model. Multiple imputation is commonly used to handle these missing data. Joint model multiple imputation and full-conditional specification multiple imputation are known to yield imputed data with the same asymptotic distribution when the conditional models of full-conditional specification are compatible with that joint model. We show that this asymptotic equivalence of imputation distributions does not imply that joint model multiple imputation and full-conditional specification multiple imputation will also yield asymptotically equally efficient inference about the parameters of the model of interest, nor that they will be equally robust to misspecification of the joint model. When the conditional models used by full-conditional specification multiple imputation are linear, logistic and multinomial regressions, these are compatible with a restricted general location joint model. We show that multiple imputation using the restricted general location joint model can be substantially more asymptotically efficient than full-conditional specification multiple imputation, but this typically requires very strong associations between variables. When associations are weaker, the efficiency gain is small. Moreover, full-conditional specification multiple imputation is shown to be potentially much more robust than joint model multiple imputation using the restricted general location model to mispecification of that model when there is substantial missingness in the outcome variable.

  3. Asymptotically shear-free and twist-free null geodesic congruences

    International Nuclear Information System (INIS)

    Kozameh, Carlos; Newman, Ezra T

    2007-01-01

    The Robinson-Trautman spacetime is a special case of asymptotically flat spacetimes that possess asymptotically shear-free and twist-free (surface forming) null geodesic congruences. In this paper we show that, although they are rare, a larger class of asymptotically flat spacetimes with this property does exist. In particular, we display the class of spacetimes that possess this dual property and demonstrate how these congruences can be found. In addition, we show that in each case the congruence is isolated in the sense that there are no other neighbouring congruences with this dual property

  4. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

    Directory of Open Access Journals (Sweden)

    Timothy M. Adamo

    2009-09-01

    Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in complex Minkowski space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi’s integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum–conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  5. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

    Directory of Open Access Journals (Sweden)

    Timothy M. Adamo

    2012-01-01

    Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, H-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi's integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum--conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  6. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation.

    Science.gov (United States)

    Adamo, Timothy M; Newman, Ezra T; Kozameh, Carlos

    2012-01-01

    A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, [Formula: see text]-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell) field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss) by (Bondi's) integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum-conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  7. Szegö Kernels and Asymptotic Expansions for Legendre Polynomials

    Directory of Open Access Journals (Sweden)

    Roberto Paoletti

    2017-01-01

    Full Text Available We present a geometric approach to the asymptotics of the Legendre polynomials Pk,n+1, based on the Szegö kernel of the Fermat quadric hypersurface, leading to complete asymptotic expansions holding on expanding subintervals of [-1,1].

  8. On Kolmogorov asymptotics of estimators of the misclassification error rate in linear discriminant analysis

    KAUST Repository

    Zollanvari, Amin

    2013-05-24

    We provide a fundamental theorem that can be used in conjunction with Kolmogorov asymptotic conditions to derive the first moments of well-known estimators of the actual error rate in linear discriminant analysis of a multivariate Gaussian model under the assumption of a common known covariance matrix. The estimators studied in this paper are plug-in and smoothed resubstitution error estimators, both of which have not been studied before under Kolmogorov asymptotic conditions. As a result of this work, we present an optimal smoothing parameter that makes the smoothed resubstitution an unbiased estimator of the true error. For the sake of completeness, we further show how to utilize the presented fundamental theorem to achieve several previously reported results, namely the first moment of the resubstitution estimator and the actual error rate. We provide numerical examples to show the accuracy of the succeeding finite sample approximations in situations where the number of dimensions is comparable or even larger than the sample size.

  9. On Kolmogorov asymptotics of estimators of the misclassification error rate in linear discriminant analysis

    KAUST Repository

    Zollanvari, Amin; Genton, Marc G.

    2013-01-01

    We provide a fundamental theorem that can be used in conjunction with Kolmogorov asymptotic conditions to derive the first moments of well-known estimators of the actual error rate in linear discriminant analysis of a multivariate Gaussian model under the assumption of a common known covariance matrix. The estimators studied in this paper are plug-in and smoothed resubstitution error estimators, both of which have not been studied before under Kolmogorov asymptotic conditions. As a result of this work, we present an optimal smoothing parameter that makes the smoothed resubstitution an unbiased estimator of the true error. For the sake of completeness, we further show how to utilize the presented fundamental theorem to achieve several previously reported results, namely the first moment of the resubstitution estimator and the actual error rate. We provide numerical examples to show the accuracy of the succeeding finite sample approximations in situations where the number of dimensions is comparable or even larger than the sample size.

  10. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    International Nuclear Information System (INIS)

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  11. Time-asymptotic interactions of two ensembles of Cucker-Smale flocking particles

    Science.gov (United States)

    Ha, Seung-Yeal; Ko, Dongnam; Zhang, Xiongtao; Zhang, Yinglong

    2017-07-01

    We study the time-asymptotic interactions of two ensembles of Cucker-Smale flocking particles. For this, we use a coupled hydrodynamic Cucker-Smale system and discuss two frameworks, leading to mono-cluster and bi-cluster flockings asymptotically depending on initial configurations, coupling strengths, and the far-field decay property of communication weights. Under the proposed two frameworks, we show that mono-cluster and bi-cluster flockings emerge asymptotically exponentially fast and algebraically slow, respectively. Our asymptotic analysis uses the Lyapunov functional approach and a Lagrangian formulation of the coupled system.

  12. Asymptotically Safe Standard Model Extensions arXiv

    CERN Document Server

    Pelaggi, Giulio Maria; Salvio, Alberto; Sannino, Francesco; Smirnov, Juri; Strumia, Alessandro

    We consider theories with a large number NF of charged fermions and compute the renormalisation group equations for the gauge, Yukawa and quartic couplings resummed at leading order in NF. We construct extensions of the Standard Model where SU(2) and/or SU(3) are asymptotically safe. When the same procedure is applied to the Abelian U(1) factor, we find that the Higgs quartic can not be made asymptotically safe and stay perturbative at the same time.

  13. Composite asymptotic expansions and scaling wall turbulence.

    Science.gov (United States)

    Panton, Ronald L

    2007-03-15

    In this article, the assumptions and reasoning that yield composite asymptotic expansions for wall turbulence are discussed. Particular attention is paid to the scaling quantities that are used to render the variables non-dimensional and of order one. An asymptotic expansion is proposed for the streamwise Reynolds stress that accounts for the active and inactive turbulence by using different scalings. The idea is tested with the data from the channel flows and appears to have merit.

  14. arXiv Asymptotically Safe Standard Model Extensions?

    CERN Document Server

    Pelaggi, Giulio Maria; Salvio, Alberto; Sannino, Francesco; Smirnov, Juri; Strumia, Alessandro

    2018-05-15

    We consider theories with a large number NF of charged fermions and compute the renormalization group equations for the gauge, Yukawa and quartic couplings resummed at leading order in 1/NF. We construct extensions of the standard model where SU(2) and/or SU(3) are asymptotically safe. When the same procedure is applied to the Abelian U(1) factor, we find that the Higgs quartic can not be made asymptotically safe and stay perturbative at the same time.

  15. Asymptotic time dependent neutron transport in multidimensional systems

    International Nuclear Information System (INIS)

    Nagy, M.E.; Sawan, M.E.; Wassef, W.A.; El-Gueraly, L.A.

    1983-01-01

    A model which predicts the asymptotic time behavior of the neutron distribution in multi-dimensional systems is presented. The model is based on the kernel factorization method used for stationary neutron transport in a rectangular parallelepiped. The accuracy of diffusion theory in predicting the asymptotic time dependence is assessed. The use of neutron pulse experiments for predicting the diffusion parameters is also investigated

  16. Some asymptotic properties of functions holomorphic in tubular domains

    International Nuclear Information System (INIS)

    Zavialov, B.I.

    1988-10-01

    For the function holomorphic in curved tubular domain the connection between asymptotic behaviour of real part of its boundary value at a given point of base manifold and asymptotic behaviour of the whole function from the inside of this domain is studied. (author). 3 refs

  17. Asymptotically double lacunry equivalent sequences defined by Orlicz functions

    Directory of Open Access Journals (Sweden)

    Ayhan Esi

    2014-04-01

    Full Text Available This paper presents the following definition which is natural combition of the definition for asymptotically equivalent and Orlicz function. The two nonnegative double sequences x=(x_{k,l} and y=(y_{k,l} are said to be M-asymptotically double equivalent to multiple L provided that for every ε>0, P-lim_{k,l}M(((|((x_{k,l}/(y_{k,l}-L|/ρ=0, for some ρ>0, (denoted by x∽y and simply M-asymptotically double equivalent if L=1. Also we give some new concepts related to this definition and some inclusion theorems.

  18. The laser second threshold: Its exact analytical dependence on detuning and relaxation rates

    International Nuclear Information System (INIS)

    Bakasov, A.A.; Abraham, N.B.

    1992-11-01

    An exact analysis has been carried out for general analytical expressions for the second threshold of a single-mode homogeneously broadened laser and for the initial pulsation frequency at the second threshold for arbitrary physical values of the relaxation rates, and at arbitrary detuning between the cavity frequency and the atomic resonance frequency. These expressions also give correspondingly exact forms for asymptotic cases that have previously studied with some approximations. Earlier approximate results are partly confirmed and partly improved by these more general expressions. The physical status of various expressions and approximations is re-considered and specified more clearly, including an analysis of which reasonably can be attained in lasers or masers. A general analytical proof is given that for larger detuning of the laser cavity from resonance a higher value of the laser excitation is required to destabilize the steady state solution (the second threshold). We also present results for the minimum value of the second threshold at fixed detuning as a function of the other parameters of the system and on the dependence of the ratio of the second threshold to the first threshold as a function of detuning. Minima of the second threshold and of the threshold ratio occur only if the population relaxation rate is equal to zero. The minima of the threshold ratio are shown to be bounded from above as well as from below (as functions of the relaxation rates, so long as the second threshold exists). The upper bound on the threshold ratio is equal to 17. The variation of the second threshold in the semi-infinite parameter space of the decay rates is shown at various detunings in plots with a finite domain by normalizing the material relaxation rates to the cavity decay rate. (author). 53 refs, 22 figs, 3 tabs

  19. Asymptotic solutions of miscible displacements in geometries of large aspect ratio

    International Nuclear Information System (INIS)

    Yang, Z.; Yortsos, Y.C.

    1997-01-01

    Asymptotic solutions are developed for miscible displacements at Stokes flow conditions between parallel plates or in a cylindrical capillary, at large values of the geometric aspect ratio. The single integro-differential equation obtained is solved numerically for different values of the Pacute eclet number and the viscosity ratio. At large values of the latter, the solution consists of a symmetric finger propagating in the middle of the gap or the capillary. Constraints on conventional convection-dispersion-equation approach for studying miscible instabilities in planar Hele endash Shaw cells are obtained. The asymptotic formalism is next used to derive emdash in the limit of zero diffusion emdash a hyperbolic equation for the cross-sectionally averaged concentration, the solution of which is obtained by analytical means. This solution is valid as long as sharp shock fronts do not form. The results are compared with recent numerical simulations of the full problem and experiments of miscible displacement in a narrow capillary. copyright 1997 American Institute of Physics

  20. Single-Molecule Imaging Reveals Topology Dependent Mutual Relaxation of Polymer Chains

    KAUST Repository

    Abadi, Maram; Serag, Maged F.; Habuchi, Satoshi

    2015-01-01

    The motion and relaxation of linear and cyclic polymers under entangled conditions are investigated by means of a newly developed single-molecule tracking technique, cumulative-area (CA) tracking. CA tracking enables simultaneous quantitative characterization of the diffusion mode, diffusion rate, and relaxation time that have been impossible with a widely used conventional single-molecule localization and tracking method, by analyzing cumulative areas occupied by the moving molecule. Using the novel approach, we investigate the motion and relaxation of entangled cyclic polymers, which have been an important but poorly understood question. Fluorescently labeled 42 kbp linear or cyclic tracer dsDNAs in concentrated solutions of unlabeled linear or cyclic DNAs are used as model systems. We show that CA tracking can explicitly distinguish topology-dependent diffusion mode, rate, and relaxation time, demonstrating that the method provides an invaluable tool for characterizing topological interaction between the entangled chains. We further demonstrate that the current models proposed for the entanglement between cyclic polymers which are based on cyclic chains moving through an array of fixed obstacles cannot correctly describe the motion of the cyclic chain under the entangled conditions. Our results rather suggest the mutual relaxation of the cyclic chains, which underscore the necessity of developing a new model to describe the motion of cyclic polymer under the entangled conditions based on the mutual interaction of the chains.

  1. Single-Molecule Imaging Reveals Topology Dependent Mutual Relaxation of Polymer Chains

    KAUST Repository

    Abadi, Maram

    2015-08-24

    The motion and relaxation of linear and cyclic polymers under entangled conditions are investigated by means of a newly developed single-molecule tracking technique, cumulative-area (CA) tracking. CA tracking enables simultaneous quantitative characterization of the diffusion mode, diffusion rate, and relaxation time that have been impossible with a widely used conventional single-molecule localization and tracking method, by analyzing cumulative areas occupied by the moving molecule. Using the novel approach, we investigate the motion and relaxation of entangled cyclic polymers, which have been an important but poorly understood question. Fluorescently labeled 42 kbp linear or cyclic tracer dsDNAs in concentrated solutions of unlabeled linear or cyclic DNAs are used as model systems. We show that CA tracking can explicitly distinguish topology-dependent diffusion mode, rate, and relaxation time, demonstrating that the method provides an invaluable tool for characterizing topological interaction between the entangled chains. We further demonstrate that the current models proposed for the entanglement between cyclic polymers which are based on cyclic chains moving through an array of fixed obstacles cannot correctly describe the motion of the cyclic chain under the entangled conditions. Our results rather suggest the mutual relaxation of the cyclic chains, which underscore the necessity of developing a new model to describe the motion of cyclic polymer under the entangled conditions based on the mutual interaction of the chains.

  2. Asymptotic structure of space-time with a positive cosmological constant

    Science.gov (United States)

    Kesavan, Aruna

    In general relativity a satisfactory framework for describing isolated systems exists when the cosmological constant Lambda is zero. The detailed analysis of the asymptotic structure of the gravitational field, which constitutes the framework of asymptotic flatness, lays the foundation for research in diverse areas in gravitational science. However, the framework is incomplete in two respects. First, asymptotic flatness provides well-defined expressions for physical observables such as energy and momentum as 'charges' of asymptotic symmetries at null infinity, [special character omitted] +. But the asymptotic symmetry group, called the Bondi-Metzner-Sachs group is infinite-dimensional and a tensorial expression for the 'charge' integral of an arbitrary BMS element is missing. We address this issue by providing a charge formula which is a 2-sphere integral over fields local to the 2-sphere and refers to no extraneous structure. The second, and more significant shortcoming is that observations have established that Lambda is not zero but positive in our universe. Can the framework describing isolated systems and their gravitational radiation be extended to incorporate this fact? In this dissertation we show that, unfortunately, the standard framework does not extend from the Lambda = 0 case to the Lambda > 0 case in a physically useful manner. In particular, we do not have an invariant notion of gravitational waves in the non-linear regime, nor an analog of the Bondi 'news tensor', nor positive energy theorems. In addition, we argue that the stronger boundary condition of conformal flatness of intrinsic metric on [special character omitted]+, which reduces the asymptotic symmetry group from Diff([special character omitted]) to the de Sitter group, is insufficient to characterize gravitational fluxes and is physically unreasonable. To obtain guidance for the full non-linear theory with Lambda > 0, linearized gravitational waves in de Sitter space-time are analyzed in

  3. Coulomb string tension, asymptotic string tension, and the gluon chain

    OpenAIRE

    Greensite, Jeff; Szczepaniak, Adam P.

    2014-01-01

    We compute, via numerical simulations, the non-perturbative Coulomb potential of pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.

  4. Asymptotic estimates and exponential stability for higher-order monotone difference equations

    Directory of Open Access Journals (Sweden)

    Pituk Mihály

    2005-01-01

    Full Text Available Asymptotic estimates are established for higher-order scalar difference equations and inequalities the right-hand sides of which generate a monotone system with respect to the discrete exponential ordering. It is shown that in some cases the exponential estimates can be replaced with a more precise limit relation. As corollaries, a generalization of discrete Halanay-type inequalities and explicit sufficient conditions for the global exponential stability of the zero solution are given.

  5. Asymptotic estimates and exponential stability for higher-order monotone difference equations

    Directory of Open Access Journals (Sweden)

    Mihály Pituk

    2005-03-01

    Full Text Available Asymptotic estimates are established for higher-order scalar difference equations and inequalities the right-hand sides of which generate a monotone system with respect to the discrete exponential ordering. It is shown that in some cases the exponential estimates can be replaced with a more precise limit relation. As corollaries, a generalization of discrete Halanay-type inequalities and explicit sufficient conditions for the global exponential stability of the zero solution are given.

  6. Directions for model building from asymptotic safety

    Science.gov (United States)

    Bond, Andrew D.; Hiller, Gudrun; Kowalska, Kamila; Litim, Daniel F.

    2017-08-01

    Building on recent advances in the understanding of gauge-Yukawa theories we explore possibilities to UV-complete the Standard Model in an asymptotically safe manner. Minimal extensions are based on a large flavor sector of additional fermions coupled to a scalar singlet matrix field. We find that asymptotic safety requires fermions in higher representations of SU(3) C × SU(2) L . Possible signatures at colliders are worked out and include R-hadron searches, diboson signatures and the evolution of the strong and weak coupling constants.

  7. Contractive relaxation systems and interacting particles for scalar conservation laws

    International Nuclear Information System (INIS)

    Katsoulakis, M.A.; Tzavaras, A.E.

    1996-01-01

    We consider a class of semi linear hyperbolic systems with relaxation that are contractive in the L 1 -norm and admit invariant regions. We show that, as the relaxation parameter ξ goes to zero, their solutions converge to a weak solution of the scalar multidimensional conversation law that satisfies the Kruzhkov conditions. In the case of one space dimension, we propose certain interacting particle systems, whose mesoscopic limit is the systems with relaxation and their macroscopic dynamics is described by entropy solutions of a scalar conservation law. (author)

  8. Asymptotic convergence for iterative optimization in electronic structure

    International Nuclear Information System (INIS)

    Lippert, Ross A.; Sears, Mark P.

    2000-01-01

    There have recently been a number of proposals for solving large electronic structure problems (local-density approximation, Hartree-Fock, and tight-binding methods) iteratively with a computational effort proportional to the size of the system. The effort needed to perform a single iteration in these schemes is well understood but the convergence rate has been an empirical matter. This paper will show that many of the proposed methods have a single underlying geometrical structure, which has a specific asymptotic convergence behavior, and that behavior can be understood in terms of some simple condition numbers based on the spectrum of the Hamiltonian. (c) 2000 The American Physical Society

  9. Global asymptotic stability of density dependent integral population projection models.

    Science.gov (United States)

    Rebarber, Richard; Tenhumberg, Brigitte; Townley, Stuart

    2012-02-01

    Many stage-structured density dependent populations with a continuum of stages can be naturally modeled using nonlinear integral projection models. In this paper, we study a trichotomy of global stability result for a class of density dependent systems which include a Platte thistle model. Specifically, we identify those systems parameters for which zero is globally asymptotically stable, parameters for which there is a positive asymptotically stable equilibrium, and parameters for which there is no asymptotically stable equilibrium. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Asymptotic Expansions for Higher-Order Scalar Difference Equations

    Directory of Open Access Journals (Sweden)

    Pituk Mihály

    2007-01-01

    Full Text Available We give an asymptotic expansion of the solutions of higher-order Poincaré difference equation in terms of the characteristic solutions of the limiting equation. As a consequence, we obtain an asymptotic description of the solutions approaching a hyperbolic equilibrium of a higher-order nonlinear difference equation with sufficiently smooth nonlinearity. The proof is based on the inversion formula for the z -transform and the residue theorem.

  11. Asymptotic behaviour of solutions of real two-dimensional differential system with nonconstant delay in an unstable case

    Directory of Open Access Journals (Sweden)

    J. Kalas

    2012-01-01

    Full Text Available The asymptotic behaviour for the solutions of a real two-dimensional system with a bounded nonconstant delay is studied under the assumption of instability. Our results improve and complement previous results by J. Kalas, where the sufficient conditions assuring the existence of bounded solutions or solutions tending to origin for $t$ approaching infinity are given. The method of investigation is based on the transformation of the considered real system to one equation with complex-valued coefficients. Asymptotic properties of this equation are studied by means of a suitable Lyapunov-Krasovskii functional and by virtue of the Wazewski topological principle.

  12. Asymptotic structure of isolated systems

    International Nuclear Information System (INIS)

    Beig, R.

    1988-01-01

    I discuss the general ideas underlying the subject of ''asymptotics'' in general relativity and describe the current status of the concepts resulting from these ideas. My main concern will be the problem of consistency. By this I mean the question as to whether the geometric assumptions inherent in these concepts are compatible with the dynamics of the theory, as determined by Einstein's equations. This rather strong bias forces me to leave untouched several issues related to asymptotics, discussed in the recent literature, some of which are perhaps thought equally, or more important, by other workers in the field. In addition I shall, for coherence of presentation, mainly consider Einstein's equations in vacuo. When attention is confined to small neighbourhoods of null and spacelike infinity, this restriction is not important, but is surely relevant for more global issues. (author)

  13. Regge asymptotics of scattering with flavour exchange in QCD

    International Nuclear Information System (INIS)

    Kirschner, R.

    1994-06-01

    The contribution to the perturbative Regge asymptotics of the exchange of two reggeized fermions with opposite helicity is investigated. The methods of conformal symmetry known for the case of gluon exchange are extended to this case where double-logarithmic contributions dominate the asymptotics. The Regge trajectories at large momentum transfer are calculated. (orig.)

  14. On the asymptotics of dimers on tori

    OpenAIRE

    Kenyon, Richard W.; Sun, Nike; Wilson, David B.

    2013-01-01

    We study asymptotics of the dimer model on large toric graphs. Let $\\mathbb L$ be a weighted $\\mathbb{Z}^2$-periodic planar graph, and let $\\mathbb{Z}^2 E$ be a large-index sublattice of $\\mathbb{Z}^2$. For $\\mathbb L$ bipartite we show that the dimer partition function on the quotient $\\mathbb{L}/(\\mathbb{Z}^2 E)$ has the asymptotic expansion $\\exp[A f_0 + \\text{fsc} + o(1)]$, where $A$ is the area of $\\mathbb{L}/(\\mathbb{Z}^2 E)$, $f_0$ is the free energy density in the bulk, and $\\text{fsc...

  15. Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size

    Science.gov (United States)

    King, Richard B.

    2016-01-01

    Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females) and annual growth increments of individuals of unknown age (1,152 males, 730 females). We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631–820 mm snout-vent length in males and from 835–1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further investigation. PMID

  16. Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size.

    Directory of Open Access Journals (Sweden)

    Richard B King

    Full Text Available Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females and annual growth increments of individuals of unknown age (1,152 males, 730 females. We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631-820 mm snout-vent length in males and from 835-1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further

  17. An asymptotic formula of the divergent bilateral basic hypergeometric series

    OpenAIRE

    Morita, Takeshi

    2012-01-01

    We show an asymptotic formula of the divergent bilateral basic hypergeometric series ${}_1\\psi_0 (a;-;q,\\cdot)$ with using the $q$-Borel-Laplace method. We also give the limit $q\\to 1-0$ of our asymptotic formula.

  18. Asymptotically Almost Periodic Solutions of Evolution Equations in Banach Spaces

    Science.gov (United States)

    Ruess, W. M.; Phong, V. Q.

    Tile linear abstract evolution equation (∗) u'( t) = Au( t) + ƒ( t), t ∈ R, is considered, where A: D( A) ⊂ E → E is the generator of a strongly continuous semigroup of operators in the Banach space E. Starting from analogs of Kadets' and Loomis' Theorems for vector valued almost periodic Functions, we show that if σ( A) ∩ iR is countable and ƒ: R → E is [asymptotically] almost periodic, then every bounded and uniformly continuous solution u to (∗) is [asymptotically] almost periodic, provided e-λ tu( t) has uniformly convergent means for all λ ∈ σ( A) ∩ iR. Related results on Eberlein-weakly asymptotically almost periodic, periodic, asymptotically periodic and C 0-solutions of (∗), as well as on the discrete case of solutions of difference equations are included.

  19. Caustics, counting maps and semi-classical asymptotics

    Science.gov (United States)

    Ercolani, N. M.

    2011-02-01

    This paper develops a deeper understanding of the structure and combinatorial significance of the partition function for Hermitian random matrices. The coefficients of the large N expansion of the logarithm of this partition function, also known as the genus expansion (and its derivatives), are generating functions for a variety of graphical enumeration problems. The main results are to prove that these generating functions are, in fact, specific rational functions of a distinguished irrational (algebraic) function, z0(t). This distinguished function is itself the generating function for the Catalan numbers (or generalized Catalan numbers, depending on the choice of weight of the parameter t). It is also a solution of the inviscid Burgers equation for certain initial data. The shock formation, or caustic, of the Burgers characteristic solution is directly related to the poles of the rational forms of the generating functions. As an intriguing application, one gains new insights into the relation between certain derivatives of the genus expansion, in a double-scaling limit, and the asymptotic expansion of the first Painlevé transcendent. This provides a precise expression of the Painlevé asymptotic coefficients directly in terms of the coefficients of the partial fractions expansion of the rational form of the generating functions established in this paper. Moreover, these insights point towards a more general program relating the first Painlevé hierarchy to the higher order structure of the double-scaling limit through the specific rational structure of generating functions in the genus expansion. The paper closes with a discussion of the relation of this work to recent developments in understanding the asymptotics of graphical enumeration. As a by-product, these results also yield new information about the asymptotics of recurrence coefficients for orthogonal polynomials with respect to exponential weights, the calculation of correlation functions for certain

  20. Caustics, counting maps and semi-classical asymptotics

    International Nuclear Information System (INIS)

    Ercolani, N M

    2011-01-01

    This paper develops a deeper understanding of the structure and combinatorial significance of the partition function for Hermitian random matrices. The coefficients of the large N expansion of the logarithm of this partition function, also known as the genus expansion (and its derivatives), are generating functions for a variety of graphical enumeration problems. The main results are to prove that these generating functions are, in fact, specific rational functions of a distinguished irrational (algebraic) function, z 0 (t). This distinguished function is itself the generating function for the Catalan numbers (or generalized Catalan numbers, depending on the choice of weight of the parameter t). It is also a solution of the inviscid Burgers equation for certain initial data. The shock formation, or caustic, of the Burgers characteristic solution is directly related to the poles of the rational forms of the generating functions. As an intriguing application, one gains new insights into the relation between certain derivatives of the genus expansion, in a double-scaling limit, and the asymptotic expansion of the first Painlevé transcendent. This provides a precise expression of the Painlevé asymptotic coefficients directly in terms of the coefficients of the partial fractions expansion of the rational form of the generating functions established in this paper. Moreover, these insights point towards a more general program relating the first Painlevé hierarchy to the higher order structure of the double-scaling limit through the specific rational structure of generating functions in the genus expansion. The paper closes with a discussion of the relation of this work to recent developments in understanding the asymptotics of graphical enumeration. As a by-product, these results also yield new information about the asymptotics of recurrence coefficients for orthogonal polynomials with respect to exponential weights, the calculation of correlation functions for certain

  1. Asymptotic limits of a statistical transport description

    International Nuclear Information System (INIS)

    Malvagi, F.; Levermore, C.D.; Pomraning, G.C.; Department of Mathematics, University of Arizona, Tucson, AZ 85721)

    1989-01-01

    We consider three different asymptotic limits of a model describing linear particle transport in a stochastic medium consisting of two randomly mixed immiscible fluids. These three limits are: (1) the fluid packets are small compared to the particle mean free path in the packet; (2) a small amount of large cross section fluid is admixed with a large amount of small cross section fluid; and (3) the angular dependence of the intensity (angular flux) is nearly isotropic. The first two limits reduce the underlying model, which consists of two coupled transport equations, to a single transport equation of the usual form. The third limit yields a two-equation diffusion approximation, and a boundary layer analysis gives boundary conditions for these two coupled diffusion equations

  2. Asymptotics for a special solution to the second member of the Painleve I hierarchy

    International Nuclear Information System (INIS)

    Claeys, T

    2010-01-01

    We study the asymptotic behavior of a special smooth solution y(x, t) to the second member of the Painleve I hierarchy. This solution arises in random matrix theory and in the study of the Hamiltonian perturbations of hyperbolic equations. The asymptotic behavior of y(x, t) if x → ±∞ (for fixed t) is known and relatively simple, but it turns out to be more subtle when x and t tend to infinity simultaneously. We distinguish a region of algebraic asymptotic behavior and a region of elliptic asymptotic behavior, and we obtain rigorous asymptotics in both regions. We also discuss two critical transitional asymptotic regimes.

  3. Watermelon configurations with wall interaction: exact and asymptotic results

    Energy Technology Data Exchange (ETDEWEB)

    Krattenthaler, C [Institut Camille Jordan, Universite Claude Bernard Lyon-I, 21, avenue Claude Bernard, F-69622 Villeurbanne Cedex (France)

    2006-06-15

    We perform an exact and asymptotic analysis of the model of n vicious walkers interacting with a wall via contact potentials, a model introduced by Brak, Essam and Owczarek. More specifically, we study the partition function of watermelon configurations which start on the wall, but may end at arbitrary height, and their mean number of contacts with the wall. We improve and extend the earlier (partially nonrigorous) results by Brak, Essam and Owczarek, providing new exact results, and more precise and more general asymptotic results, in particular full asymptotic expansions for the partition function and the mean number of contacts. Furthermore, we relate this circle of problems to earlier results in the combinatorial and statistical literature.

  4. Watermelon configurations with wall interaction: exact and asymptotic results

    International Nuclear Information System (INIS)

    Krattenthaler, C

    2006-01-01

    We perform an exact and asymptotic analysis of the model of n vicious walkers interacting with a wall via contact potentials, a model introduced by Brak, Essam and Owczarek. More specifically, we study the partition function of watermelon configurations which start on the wall, but may end at arbitrary height, and their mean number of contacts with the wall. We improve and extend the earlier (partially nonrigorous) results by Brak, Essam and Owczarek, providing new exact results, and more precise and more general asymptotic results, in particular full asymptotic expansions for the partition function and the mean number of contacts. Furthermore, we relate this circle of problems to earlier results in the combinatorial and statistical literature

  5. Watermelon configurations with wall interaction: exact and asymptotic results

    Science.gov (United States)

    Krattenthaler, C.

    2006-06-01

    We perform an exact and asymptotic analysis of the model of n vicious walkers interacting with a wall via contact potentials, a model introduced by Brak, Essam and Owczarek. More specifically, we study the partition function of watermelon configurations which start on the wall, but may end at arbitrary height, and their mean number of contacts with the wall. We improve and extend the earlier (partially nonrigorous) results by Brak, Essam and Owczarek, providing new exact results, and more precise and more general asymptotic results, in particular full asymptotic expansions for the partition function and the mean number of contacts. Furthermore, we relate this circle of problems to earlier results in the combinatorial and statistical literature.

  6. Asymptotic Expansions for Higher-Order Scalar Difference Equations

    Directory of Open Access Journals (Sweden)

    Ravi P. Agarwal

    2007-04-01

    Full Text Available We give an asymptotic expansion of the solutions of higher-order Poincaré difference equation in terms of the characteristic solutions of the limiting equation. As a consequence, we obtain an asymptotic description of the solutions approaching a hyperbolic equilibrium of a higher-order nonlinear difference equation with sufficiently smooth nonlinearity. The proof is based on the inversion formula for the z -transform and the residue theorem.

  7. Relaxation characteristics of hastelloy X

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko

    1980-02-01

    Relaxation diagrams of Hastelloy X (relaxation curves, relaxation design diagrams, etc.) were generated from the creep constitutive equation of Hastelloy X, using inelastic stress analysis code TEPICC-J. These data are in good agreement with experimental relaxation data of ORNL-5479. Three typical inelastic stress analyses were performed for various relaxation behaviors of the high-temperature structures. An attempt was also made to predict these relaxation behaviors by the relaxation curves. (author)

  8. Corroborative evidences of TV γ -scaling of the α-relaxation originating from the primitive relaxation/JG β relaxation

    Science.gov (United States)

    Ngai, K. L.; Paluch, M.

    2017-12-01

    Successful thermodynamic scaling of the structural alpha-relaxation time or transport coefficients of glass-forming liquids determined at various temperatures T and pressures P means the data conform to a single function of the product variable TVgamma, where V is the specific volume and gamma is a material specific constant. In the past two decades we have witnessed successful TVgamma-scaling in many molecular, polymeric, and even metallic glass-formers, and gamma is related to the slope of the repulsive part of the intermolecular potential. The advances made indicate TVgamma-scaling is an important aspect of the dynamic and thermodynamic properties of glass-formers. In this paper we show the origin of TVgamma-scaling is not from the structural alpha-relaxation time. Instead it comes from its precursor, the Johari-Goldstein beta-relaxation or the primitive relaxation of the Coupling Model and their relaxation times or tau_0 respectively. It is remarkable that all relaxation times are functions of TVgamma with the same gama, as well as the fractional exponent of the Kohlrausch correlation function of the structural alpha-relaxation. We arrive at this conclusion convincingly based on corroborative evidences from a number of experiments and molecular dynamics simulations performed on a wide variety of glass-formers and in conjunction with consistency with the predictions of the Coupling Model.

  9. Numerical Asymptotic Solutions Of Differential Equations

    Science.gov (United States)

    Thurston, Gaylen A.

    1992-01-01

    Numerical algorithms derived and compared with classical analytical methods. In method, expansions replaced with integrals evaluated numerically. Resulting numerical solutions retain linear independence, main advantage of asymptotic solutions.

  10. Capturing molecular multimode relaxation processes in excitable gases based on decomposition of acoustic relaxation spectra

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Wang, Shu; Zhang, Kesheng

    2017-08-01

    Existing two-frequency reconstructive methods can only capture primary (single) molecular relaxation processes in excitable gases. In this paper, we present a reconstructive method based on the novel decomposition of frequency-dependent acoustic relaxation spectra to capture the entire molecular multimode relaxation process. This decomposition of acoustic relaxation spectra is developed from the frequency-dependent effective specific heat, indicating that a multi-relaxation process is the sum of the interior single-relaxation processes. Based on this decomposition, we can reconstruct the entire multi-relaxation process by capturing the relaxation times and relaxation strengths of N interior single-relaxation processes, using the measurements of acoustic absorption and sound speed at 2N frequencies. Experimental data for the gas mixtures CO2-N2 and CO2-O2 validate our decomposition and reconstruction approach.

  11. Asymptotic behavior of equilibrium states of reaction-diffusion systems with mass conservation

    Science.gov (United States)

    Chern, Jann-Long; Morita, Yoshihisa; Shieh, Tien-Tsan

    2018-01-01

    We deal with a stationary problem of a reaction-diffusion system with a conservation law under the Neumann boundary condition. It is shown that the stationary problem turns to be the Euler-Lagrange equation of an energy functional with a mass constraint. When the domain is the finite interval (0 , 1), we investigate the asymptotic profile of a strictly monotone minimizer of the energy as d, the ratio of the diffusion coefficient of the system, tends to zero. In view of a logarithmic function in the leading term of the potential, we get to a scaling parameter κ satisfying the relation ε : =√{ d } =√{ log ⁡ κ } /κ2. The main result shows that a sequence of minimizers converges to a Dirac mass multiplied by the total mass and that by a scaling with κ the asymptotic profile exhibits a parabola in the nonvanishing region. We also prove the existence of an unstable monotone solution when the mass is small.

  12. Asymptotic analysis of discrete schemes for non-equilibrium radiation diffusion

    International Nuclear Information System (INIS)

    Cui, Xia; Yuan, Guang-wei; Shen, Zhi-jun

    2016-01-01

    Motivated by providing well-behaved fully discrete schemes in practice, this paper extends the asymptotic analysis on time integration methods for non-equilibrium radiation diffusion in [2] to space discretizations. Therein studies were carried out on a two-temperature model with Larsen's flux-limited diffusion operator, both the implicitly balanced (IB) and linearly implicit (LI) methods were shown asymptotic-preserving. In this paper, we focus on asymptotic analysis for space discrete schemes in dimensions one and two. First, in construction of the schemes, in contrast to traditional first-order approximations, asymmetric second-order accurate spatial approximations are devised for flux-limiters on boundary, and discrete schemes with second-order accuracy on global spatial domain are acquired consequently. Then by employing formal asymptotic analysis, the first-order asymptotic-preserving property for these schemes and furthermore for the fully discrete schemes is shown. Finally, with the help of manufactured solutions, numerical tests are performed, which demonstrate quantitatively the fully discrete schemes with IB time evolution indeed have the accuracy and asymptotic convergence as theory predicts, hence are well qualified for both non-equilibrium and equilibrium radiation diffusion. - Highlights: • Provide AP fully discrete schemes for non-equilibrium radiation diffusion. • Propose second order accurate schemes by asymmetric approach for boundary flux-limiter. • Show first order AP property of spatially and fully discrete schemes with IB evolution. • Devise subtle artificial solutions; verify accuracy and AP property quantitatively. • Ideas can be generalized to 3-dimensional problems and higher order implicit schemes.

  13. Spectral asymptotics of a strong δ′ interaction supported by a surface

    International Nuclear Information System (INIS)

    Exner, Pavel; Jex, Michal

    2014-01-01

    Highlights: • Attractive δ ′ interactions supported by a smooth surface are considered. • Surfaces can be either infinite and asymptotically planar, or compact and closed. • Spectral asymptotics is determined by the geometry of the interaction support. - Abstract: We derive asymptotic expansion for the spectrum of Hamiltonians with a strong attractive δ ′ interaction supported by a smooth surface in R 3 , either infinite and asymptotically planar, or compact and closed. Its second term is found to be determined by a Schrödinger type operator with an effective potential expressed in terms of the interaction support curvatures

  14. Relaxed plasma-vacuum systems

    International Nuclear Information System (INIS)

    Spies, G.O.; Lortz, D.; Kaiser, R.

    2001-01-01

    Taylor's theory of relaxed toroidal plasmas (states of lowest energy with fixed total magnetic helicity) is extended to include a vacuum between the plasma and the wall. In the extended variational problem, one prescribes, in addition to the helicity and the magnetic fluxes whose conservation follows from the perfect conductivity of the wall, the fluxes whose conservation follows from the assumption that the plasma-vacuum interface is also perfectly conducting (if the wall is a magnetic surface, then one has the toroidal and the poloidal flux in the vacuum). Vanishing of the first energy variation implies a pressureless free-boundary magnetohydrostatic equilibrium with a Beltrami magnetic field in the plasma, and in general with a surface current in the interface. Positivity of the second variation implies that the equilibrium is stable according to ideal magnetohydrodynamics, that it is a relaxed state according to Taylor's theory if the interface is replaced by a wall, and that the surface current is nonzero (at least if there are no closed magnetic field lines in the interface). The plane slab, with suitable boundary conditions to simulate a genuine torus, is investigated in detail. The relaxed state has the same double symmetry as the vessel if, and only if, the prescribed helicity is in an interval that depends on the prescribed fluxes. This interval is determined in the limit of a thin slab

  15. Theory of vibrational relaxation in mixtures of ortho- and para-hydrogen

    International Nuclear Information System (INIS)

    Moise, A.; Pritchard, H.O.

    1981-01-01

    A numerical study of the vibrational relaxation at 500 K of a mixture of ortho-H 2 and para-H 2 is described. The required state-to-state rate constants were calculated and missing pieces of data were estimated by interpolation. It is concluded that only one relaxation time will be observed in any mixture of orth-H 2 and para-H 2 and that (except at very high dilutions in a third inert gas) the relaxation rate constant will be close to the mean of the individual rate constants for relaxation, weighted according to the respective mole fractions of ortho-H 2 and para-H 2 present in the mixture. The relaxation process can be modelled as an electrical RC network, whose time constants can be written down as sums of the appropriate microscopic rate constants. By using this model the conditions required for a mixture of two gases to exhibit two distinct vibrational relaxation times can be explored

  16. Asymptotic chaos expansions in finance theory and practice

    CERN Document Server

    Nicolay, David

    2014-01-01

    Stochastic instantaneous volatility models such as Heston, SABR or SV-LMM have mostly been developed to control the shape and joint dynamics of the implied volatility surface. In principle, they are well suited for pricing and hedging vanilla and exotic options, for relative value strategies or for risk management. In practice however, most SV models lack a closed form valuation for European options. This book presents the recently developed Asymptotic Chaos Expansions methodology (ACE) which addresses that issue. Indeed its generic algorithm provides, for any regular SV model, the pure asymptotes at any order for both the static and dynamic maps of the implied volatility surface. Furthermore, ACE is programmable and can complement other approximation methods. Hence it allows a systematic approach to designing, parameterising, calibrating and exploiting SV models, typically for Vega hedging or American Monte-Carlo. Asymptotic Chaos Expansions in Finance illustrates the ACE approach for single underlyings (suc...

  17. Contact mechanics of articular cartilage layers asymptotic models

    CERN Document Server

    Argatov, Ivan

    2015-01-01

    This book presents a comprehensive and unifying approach to articular contact mechanics with an emphasis on frictionless contact interaction of thin cartilage layers. The first part of the book (Chapters 1–4) reviews the results of asymptotic analysis of the deformational behavior of thin elastic and viscoelastic layers. A comprehensive review of the literature is combined with the authors’ original contributions. The compressible and incompressible cases are treated separately with a focus on exact solutions for asymptotic models of frictionless contact for thin transversely isotropic layers bonded to rigid substrates shaped like elliptic paraboloids. The second part (Chapters 5, 6, and 7) deals with the non-axisymmetric contact of thin transversely isotropic biphasic layers and presents the asymptotic modelling methodology for tibio-femoral contact. The third part of the book consists of Chapter 8, which covers contact problems for thin bonded inhomogeneous transversely isotropic elastic layers, and Cha...

  18. The unusual asymptotics of three-sided prudent polygons

    International Nuclear Information System (INIS)

    Beaton, Nicholas R; Guttmann, Anthony J; Flajolet, Philippe

    2010-01-01

    We have studied the area-generating function of prudent polygons on the square lattice. Exact solutions are obtained for the generating function of two-sided and three-sided prudent polygons, and a functional equation is found for four-sided prudent polygons. This is used to generate series coefficients in polynomial time, and these are analysed to determine the asymptotics numerically. A careful asymptotic analysis of the three-sided polygons produces a most surprising result. A transcendental critical exponent is found, and the leading amplitude is not quite a constant, but is a constant plus a small oscillatory component with an amplitude approximately 10 -8 times that of the leading amplitude. This effect cannot be seen by any standard numerical analysis, but it may be present in other models. If so, it changes our whole view of the asymptotic behaviour of lattice models. (fast track communication)

  19. Structural relaxation of polydisperse hard spheres: comparison of the mode-coupling theory to a Langevin dynamics simulation.

    Science.gov (United States)

    Weysser, F; Puertas, A M; Fuchs, M; Voigtmann, Th

    2010-07-01

    We analyze the slow glassy structural relaxation as measured through collective and tagged-particle density correlation functions obtained from Brownian dynamics simulations for a polydisperse system of quasi-hard spheres in the framework of the mode-coupling theory (MCT) of the glass transition. Asymptotic analyses show good agreement for the collective dynamics when polydispersity effects are taken into account in a multicomponent calculation, but qualitative disagreement at small q when the system is treated as effectively monodisperse. The origin of the different small-q behavior is attributed to the interplay between interdiffusion processes and structural relaxation. Numerical solutions of the MCT equations are obtained taking properly binned partial static structure factors from the simulations as input. Accounting for a shift in the critical density, the collective density correlation functions are well described by the theory at all densities investigated in the simulations, with quantitative agreement best around the maxima of the static structure factor and worst around its minima. A parameter-free comparison of the tagged-particle dynamics however reveals large quantitative errors for small wave numbers that are connected to the well-known decoupling of self-diffusion from structural relaxation and to dynamical heterogeneities. While deviations from MCT behavior are clearly seen in the tagged-particle quantities for densities close to and on the liquid side of the MCT glass transition, no such deviations are seen in the collective dynamics.

  20. Asymptotic Solution of the Theory of Shells Boundary Value Problem

    Directory of Open Access Journals (Sweden)

    I. V. Andrianov

    2007-01-01

    Full Text Available This paper provides a state-of-the-art review of asymptotic methods in the theory of plates and shells. Asymptotic methods of solving problems related to theory of plates and shells have been developed by many authors. The main features of our paper are: (i it is devoted to the fundamental principles of asymptotic approaches, and (ii it deals with both traditional approaches, and less widely used, new approaches. The authors have paid special attention to examples and discussion of results rather than to burying the ideas in formalism, notation, and technical details.

  1. Asymptotics for the ratio and the zeros of multiple Charlier polynomials

    OpenAIRE

    Ndayiragije, François; Van Assche, Walter

    2011-01-01

    We investigate multiple Charlier polynomials and in particular we will use the (nearest neighbor) recurrence relation to find the asymptotic behavior of the ratio of two multiple Charlier polynomials. This result is then used to obtain the asymptotic distribution of the zeros, which is uniform on an interval. We also deal with the case where one of the parameters of the various Poisson distributions depend on the degree of the polynomial, in which case we obtain another asymptotic distributio...

  2. Asymptotic strength of thermal pulses in the helium shell burning

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, M Y [Niigata Univ. (Japan); Sugimoto, D

    1979-03-01

    Secular growth in the strength of the recurrent thermal pulses of helium shell burning is discussed for the purpose of determining its asymptotic strength. It is shown that the pulse grows stronger if the helium zone has been cooled more before the initiation of the pulse. The secular growth of the pulse is related with the increasing degree of cooling. Thermal pulses are computed for an initial model corresponding to the maximum possible cooling, i.e., for a model in which the steady-state entropy distribution was realized in the helium zone. Such thermal pulses are shown to give an upper bound to the asymptotic strength, which is close enough to the asymptotic strength itself for relatively large core masses. Numerical results are given for the core mass of 1.07 M sub(sun), for which the asymptotic strength is found to be 9 x 10/sup 6/ L sub(sun). Thermal pulses are also computed for an initial model which has been cooled artificially more than the steady-state model. The first pulse results in a much greater strength than in the normal model, but a later pulse approaches the normal asymptotic value. Such models are also discussed in relation to the shell flashes on accreting white dwarfs.

  3. Ruin problems and tail asymptotics

    DEFF Research Database (Denmark)

    Rønn-Nielsen, Anders

    The thesis Ruin Problems and Tail Asymptotics provides results on ruin problems for several classes of Markov processes. For a class of diffusion processes with jumps an explicit expression for the joint Laplace transform of the first passage time and the corresponding undershoot is derived...

  4. The asymptotic variance of departures in critically loaded queues

    NARCIS (Netherlands)

    Al Hanbali, Ahmad; Mandjes, M.R.H.; Nazarathy, Y.; Whitt, W.

    2011-01-01

    We consider the asymptotic variance of the departure counting process D(t) of the GI/G/1 queue; D(t) denotes the number of departures up to time t. We focus on the case where the system load ϱ equals 1, and prove that the asymptotic variance rate satisfies limt→∞varD(t) / t = λ(1 - 2 / π)(ca2 +

  5. Global asymptotic stability analysis of bidirectional associative memory neural networks with time delays.

    Science.gov (United States)

    Arik, Sabri

    2005-05-01

    This paper presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all continuous nonmonotonic neuron activation functions. It is shown that in some special cases of the results, the stability criteria can be easily checked. Some examples are also given to compare the results with the previous results derived in the literature.

  6. Relaxation Dynamics of a Granular Pile on a Vertically Vibrating Plate

    Science.gov (United States)

    Tsuji, Daisuke; Otsuki, Michio; Katsuragi, Hiroaki

    2018-03-01

    Nonlinear relaxation dynamics of a vertically vibrated granular pile is experimentally studied. In the experiment, the flux and slope on the relaxing pile are measured by using a high-speed laser profiler. The relation of these quantities can be modeled by the nonlinear transport law assuming the uniform vibrofluidization of an entire pile. The fitting parameter in this model is only the relaxation efficiency, which characterizes the energy conversion rate from vertical vibration into horizontal transport. We demonstrate that this value is a constant independent of experimental conditions. The actual relaxation is successfully reproduced by the continuity equation with the proposed model. Finally, its specific applicability toward an astrophysical phenomenon is shown.

  7. Large time asymptotics of solutions of the equations of principal chiral field

    International Nuclear Information System (INIS)

    Sukhanov, V.V.

    1990-01-01

    Asymptotic behaviour of solutions of the equations of principal chiral field when one of the arguments tends to infinity is investigated. Asymptotics of solutions of the corresponding spectral problem is investigated as well. explicit formulas are constructed which connect the coefficients of the asymptotic decomposition of the potential with the data of the corresponding inverse problem by means of a birational transformation

  8. Delay-dependent asymptotic stability of a two-neuron system with different time delays

    International Nuclear Information System (INIS)

    Tu Fenghua; Liao Xiaofeng; Zhang Wei

    2006-01-01

    In this paper, we consider a two-neuron system with time-delayed connections between neurons. Based on the construction of Lyapunov functionals, we obtain sufficient criteria to ensure local and global asymptotic stability of the equilibrium of the neural network. The obtained conditions are shown to be less conservative and restrictive than those reported in the literature. Some examples are included to illustrate our results

  9. Inversion of quasi-periodic deviations between low-degree solar gravity mode eigenfrequencies and asymptotic theory eigenfrequencies

    International Nuclear Information System (INIS)

    Hill, H.A.; Gao, Qiang; Rosenwald, R.D.

    1988-01-01

    The fine structure found by Gu, Hill and Rosenwald between asymptotic theory eigenfrequencies and the observed eigenfrequencies reported by Hill and Gu is interpreted as the result of conditions not being met for the applicability of asymptotic theory at one or more radii in the solar interior. From an inversion of the observed fine structure, reasonably good agreement is obtained between observation and theory for either a localized perturbation in internal structure at r/R ∼ 0.06 or at r/R ∼ 0.23. The latter solution is, however, the better one. The amplitude of the perturbation in the mean molecular weight required to produce the fine structure is also inferred. 11 refs., 2 figs

  10. The exotic heat-trace asymptotics of a regular-singular operator revisited

    OpenAIRE

    Vertman, Boris

    2013-01-01

    We discuss the exotic properties of the heat-trace asymptotics for a regular-singular operator with general boundary conditions at the singular end, as observed by Falomir, Muschietti, Pisani and Seeley as well as by Kirsten, Loya and Park. We explain how their results alternatively follow from the general heat kernel construction by Mooers, a natural question that has not been addressed yet, as the latter work did not elaborate explicitly on the singular structure of the heat trace expansion...

  11. On asymptotics and resurgent structures of enumerative Gromov-Witten invariants

    International Nuclear Information System (INIS)

    Couso-Santamaria, Ricardo; Schiappa, Ricardo; Geneve Univ.; Vaz, Ricardo; DESY Hamburg

    2016-05-01

    Making use of large-order techniques in asymptotics and resurgent analysis, this work addresses the growth of enumerative Gromov-Witten invariants - in their dependence upon genus and degree of the embedded curve - for several different threefold Calabi-Yau toric-varieties. In particular, while the leading asymptotics of these invariants at large genus or at large degree is exponential, at combined large genus and degree it turns out to be factorial. This factorial growth has a resurgent nature, originating via mirror symmetry from the resurgent-transseries description of the B-model free energy. This implies the existence of nonperturbative sectors controlling the asymptotics of the Gromov-Witten invariants, which could themselves have an enumerative-geometry interpretation. The examples addressed include: the resolved conifold; the local surfaces local P 2 and local P 1 x P 1 ; the local curves and Hurwitz theory; and the compact quintic. All examples suggest very rich interplays between resurgent asymptotics and enumerative problems in algebraic geometry.

  12. On asymptotics and resurgent structures of enumerative Gromov-Witten invariants

    Energy Technology Data Exchange (ETDEWEB)

    Couso-Santamaria, Ricardo [Lisboa Univ. (Portugal). Inst. Superior Tecnico (IST); Schiappa, Ricardo [Lisboa Univ. (Portugal). Inst. Superior Tecnico (IST); Geneve Univ. (Switzerland). Dept. de Physique Theoretique et Section de Mathematiques; Vaz, Ricardo [Lisboa Univ. (Portugal). Inst. Superior Tecnico (IST); DESY Hamburg (Germany). Theory Group

    2016-05-15

    Making use of large-order techniques in asymptotics and resurgent analysis, this work addresses the growth of enumerative Gromov-Witten invariants - in their dependence upon genus and degree of the embedded curve - for several different threefold Calabi-Yau toric-varieties. In particular, while the leading asymptotics of these invariants at large genus or at large degree is exponential, at combined large genus and degree it turns out to be factorial. This factorial growth has a resurgent nature, originating via mirror symmetry from the resurgent-transseries description of the B-model free energy. This implies the existence of nonperturbative sectors controlling the asymptotics of the Gromov-Witten invariants, which could themselves have an enumerative-geometry interpretation. The examples addressed include: the resolved conifold; the local surfaces local P{sup 2} and local P{sup 1} x P{sup 1}; the local curves and Hurwitz theory; and the compact quintic. All examples suggest very rich interplays between resurgent asymptotics and enumerative problems in algebraic geometry.

  13. Asymptotic Behavior of Solutions of Delayed Difference Equations

    Directory of Open Access Journals (Sweden)

    J. Diblík

    2011-01-01

    Full Text Available This contribution is devoted to the investigation of the asymptotic behavior of delayed difference equations with an integer delay. We prove that under appropriate conditions there exists at least one solution with its graph staying in a prescribed domain. This is achieved by the application of a more general theorem which deals with systems of first-order difference equations. In the proof of this theorem we show that a good way is to connect two techniques—the so-called retract-type technique and Liapunov-type approach. In the end, we study a special class of delayed discrete equations and we show that there exists a positive and vanishing solution of such equations.

  14. Asymptotic Limits for Transport in Binary Stochastic Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Prinja, A. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-01

    The Karhunen-Loeve stochastic spectral expansion of a random binary mixture of immiscible fluids in planar geometry is used to explore asymptotic limits of radiation transport in such mixtures. Under appropriate scalings of mixing parameters - correlation length, volume fraction, and material cross sections - and employing multiple- scale expansion of the angular flux, previously established atomic mix and diffusion limits are reproduced. When applied to highly contrasting material properties in the small cor- relation length limit, the methodology yields a nonstandard reflective medium transport equation that merits further investigation. Finally, a hybrid closure is proposed that produces both small and large correlation length limits of the closure condition for the material averaged equations.

  15. Relaxation of fibrils in blends with one viscoelastic component: Bulk and confined conditions

    NARCIS (Netherlands)

    Cardinaels, R.M.; Moldenaers, P.

    2010-01-01

    Using a counter rotating parallel plate shear flow cell, shape relaxation of fibrils in a quiescent matrix is studied microscopically. Both the effects of geometrical confinement and component viscoelasticity are systematically explored. By applying a supercritical shear flow for varying amounts of

  16. ADM Mass for Asymptotically de Sitter Space-Time

    International Nuclear Information System (INIS)

    Huang Shiming; Yue Ruihong; Jia Dongyan

    2010-01-01

    In this paper, an ADM mass formula for asymptotically de Sitter(dS) space-time is derived from the energy-momentum tensor. We take the vacuum dS space as the background and investigate the ADM mass of the (d + 3)-dimensional sphere-symmetric space with a positive cosmological constant, and find that the ADM mass of asymptotically dS space is based on the ADM mass of Schwarzschild field and the cosmological background brings some small mass contribution as well. (general)

  17. Gravitational charges of transverse asymptotically AdS spacetimes

    International Nuclear Information System (INIS)

    Cebeci, Hakan; Sarioglu, Oezguer; Tekin, Bayram

    2006-01-01

    Using Killing-Yano symmetries, we construct conserved charges of spacetimes that asymptotically approach to the flat or anti-de Sitter spaces only in certain directions. In D dimensions, this allows one to define gravitational charges (such as mass and angular momenta densities) of p-dimensional branes/solitons or any other extended objects that curve the transverse space into an asymptotically flat or AdS one. Our construction answers the question of what kind of charges the antisymmetric Killing-Yano tensors lead to

  18. Self-similar cosmological solutions with dark energy. I. Formulation and asymptotic analysis

    International Nuclear Information System (INIS)

    Harada, Tomohiro; Maeda, Hideki; Carr, B. J.

    2008-01-01

    Based on the asymptotic analysis of ordinary differential equations, we classify all spherically symmetric self-similar solutions to the Einstein equations which are asymptotically Friedmann at large distances and contain a perfect fluid with equation of state p=(γ-1)μ with 0 1). However, in the latter case there is an additional parameter associated with the weak discontinuity at the sonic point and the solutions are only asymptotically 'quasi-Friedmann', in the sense that they exhibit an angle deficit at large distances. In the 0<γ<2/3 case, there is no sonic point and there exists a one-parameter family of solutions which are genuinely asymptotically Friedmann at large distances. We find eight classes of asymptotic behavior: Friedmann or quasi-Friedmann or quasistatic or constant-velocity at large distances, quasi-Friedmann or positive-mass singular or negative-mass singular at small distances, and quasi-Kantowski-Sachs at intermediate distances. The self-similar asymptotically quasistatic and quasi-Kantowski-Sachs solutions are analytically extendible and of great cosmological interest. We also investigate their conformal diagrams. The results of the present analysis are utilized in an accompanying paper to obtain and physically interpret numerical solutions

  19. Relaxation dispersion in MRI induced by fictitious magnetic fields.

    Science.gov (United States)

    Liimatainen, Timo; Mangia, Silvia; Ling, Wen; Ellermann, Jutta; Sorce, Dennis J; Garwood, Michael; Michaeli, Shalom

    2011-04-01

    A new method entitled Relaxation Along a Fictitious Field (RAFF) was recently introduced for investigating relaxations in rotating frames of rank ≥ 2. RAFF generates a fictitious field (E) by applying frequency-swept pulses with sine and cosine amplitude and frequency modulation operating in a sub-adiabatic regime. In the present work, MRI contrast is created by varying the orientation of E, i.e. the angle ε between E and the z″ axis of the second rotating frame. When ε > 45°, the amplitude of the fictitious field E generated during RAFF is significantly larger than the RF field amplitude used for transmitting the sine/cosine pulses. Relaxation during RAFF was investigated using an invariant-trajectory approach and the Bloch-McConnell formalism. Dipole-dipole interactions between identical (like) spins and anisochronous exchange (e.g., exchange between spins with different chemical shifts) in the fast exchange regime were considered. Experimental verifications were performed in vivo in human and mouse brain. Theoretical and experimental results demonstrated that changes in ε induced a dispersion of the relaxation rate constants. The fastest relaxation was achieved at ε ≈ 56°, where the averaged contributions from transverse components during the pulse are maximal and the contribution from longitudinal components are minimal. RAFF relaxation dispersion was compared with the relaxation dispersion achieved with off-resonance spin lock T(₁ρ) experiments. As compared with the off-resonance spin lock T(₁ρ) method, a slower rotating frame relaxation rate was observed with RAFF, which under certain experimental conditions is desirable. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Thermodynamics of asymptotically safe theories

    DEFF Research Database (Denmark)

    Rischke, Dirk H.; Sannino, Francesco

    2015-01-01

    We investigate the thermodynamic properties of a novel class of gauge-Yukawa theories that have recently been shown to be completely asymptotically safe, because their short-distance behaviour is determined by the presence of an interacting fixed point. Not only do all the coupling constants freeze...

  1. Numerical relativity and asymptotic flatness

    International Nuclear Information System (INIS)

    Deadman, E; Stewart, J M

    2009-01-01

    It is highly plausible that the region of spacetime far from an isolated gravitating body is, in some sense, asymptotically Minkowskian. However theoretical studies of the full nonlinear theory, initiated by Bondi et al (1962 Proc. R. Soc. A 269 21-51), Sachs (1962 Proc. R. Soc. A 270 103-26) and Newman and Unti (1962 J. Math. Phys. 3 891-901), rely on careful, clever, a priori choices of a chart (and tetrad) and so are not readily accessible to the numerical relativist, who chooses her/his chart on the basis of quite different grounds. This paper seeks to close this gap. Starting from data available in a typical numerical evolution, we construct a chart and tetrad which are, asymptotically, sufficiently close to the theoretical ones, so that the key concepts of the Bondi news function, Bondi mass and its rate of decrease can be estimated. In particular, these estimates can be expressed in the numerical relativist's chart as numerical relativity recipes.

  2. Ratio asymptotics of Hermite-Pade polynomials for Nikishin systems

    International Nuclear Information System (INIS)

    Aptekarev, A I; Lopez, Guillermo L; Rocha, I A

    2005-01-01

    The existence of ratio asymptotics is proved for a sequence of multiple orthogonal polynomials with orthogonality relations distributed among a system of m finite Borel measures with support on a bounded interval of the real line which form a so-called Nikishin system. For m=1 this result reduces to Rakhmanov's celebrated theorem on the ratio asymptotics for orthogonal polynomials on the real line.

  3. UV conformal window for asymptotic safety

    Science.gov (United States)

    Bond, Andrew D.; Litim, Daniel F.; Vazquez, Gustavo Medina; Steudtner, Tom

    2018-02-01

    Interacting fixed points in four-dimensional gauge theories coupled to matter are investigated using perturbation theory up to three loop order. It is shown how fixed points, scaling exponents, and anomalous dimensions are obtained as a systematic power series in a small parameter. The underlying ordering principle is explained and contrasted with conventional perturbation theory and Weyl consistency conditions. We then determine the conformal window with asymptotic safety from the complete next-to-next-to-leading order in perturbation theory. Limits for the conformal window arise due to fixed point mergers, the onset of strong coupling, or vacuum instability. A consistent picture is uncovered by comparing various levels of approximation. The theory remains perturbative in the entire conformal window, with vacuum stability dictating the tightest constraints. We also speculate about a secondary conformal window at strong coupling and estimate its lower limit. Implications for model building and cosmology are indicated.

  4. Asymptotic density and effective negligibility

    Science.gov (United States)

    Astor, Eric P.

    In this thesis, we join the study of asymptotic computability, a project attempting to capture the idea that an algorithm might work correctly in all but a vanishing fraction of cases. In collaboration with Hirschfeldt and Jockusch, broadening the original investigation of Jockusch and Schupp, we introduce dense computation, the weakest notion of asymptotic computability (requiring only that the correct answer is produced on a set of density 1), and effective dense computation, where every computation halts with either the correct answer or (on a set of density 0) a symbol denoting uncertainty. A few results make more precise the relationship between these notions and work already done with Jockusch and Schupp's original definitions of coarse and generic computability. For all four types of asymptotic computation, including generic computation, we demonstrate that non-trivial upper cones have measure 0, building on recent work of Hirschfeldt, Jockusch, Kuyper, and Schupp in which they establish this for coarse computation. Their result transfers to yield a minimal pair for relative coarse computation; we generalize their method and extract a similar result for relative dense computation (and thus for its corresponding reducibility). However, all of these notions of near-computation treat a set as negligible iff it has asymptotic density 0. Noting that this definition is not computably invariant, this produces some failures of intuition and a break with standard expectations in computability theory. For instance, as shown by Hamkins and Miasnikov, the halting problem is (in some formulations) effectively densely computable, even in polynomial time---yet this result appears fragile, as indicated by Rybalov. In independent work, we respond to this by strengthening the approach of Jockusch and Schupp to avoid such phenomena; specifically, we introduce a new notion of intrinsic asymptotic density, invariant under computable permutation, with rich relations to both

  5. On calculating double logarithmical asymptotics of vertex functions defined on the mass shell

    International Nuclear Information System (INIS)

    Belokurov, V.V.; Usyukina, N.I.

    1981-01-01

    The essence of the calculation method of double logarithmical asymptotics of vertex functions defined on the mass shell is presented. Using the method the asymptotics of the form-factor of electron is calculated. The ladder and cross-ladder diagrams are asymptotically considerable in every order of the perturbation theory. The way in which the asymptotics of the 4-order diagrams is calculated has been shown. The diagrams of this order and reduction procedures for them are given in a graphic form. The photon mass μ 2 not equal to 0 plays the role of a regulator, removing infrared divergencies. The double logarithmical asymptotics of the form-factor of electron on the mass shell is calculated rigorously in an arbitrary order of the perturbation theory [ru

  6. Grid Cell Relaxation Effects on the High Frequency Vibration Characteristics

    International Nuclear Information System (INIS)

    Ryu, Joo-Young; Eom, Kyong-Bo; Jeon, Sang-Youn; Kim, Jae-Ik

    2015-01-01

    The plate structure of the grid of fuel assembly is always exposed to serious vortex induced vibration. Also, High Frequency flow induced Vibration (HFV) is primarily generated by vortex-shedding effect. When it comes to grid design as a fuel assembly component, HFV should be considered in advance since it is one of the critical factors. Excessive HFV has a possibility of making degradation of the fuel reliability that is directly related to the fuel robustness and operating performance. KEPCO NF (KNF) has performed HFV tests with various grid designs. While studying the HFV characteristics through the HFV tests, it has been observed that HFV amplitudes show different levels according to grid cell relaxation. It means that the testing could give different interpretations due to the condition of grid cell. Since the amount of relaxation is different under operating conditions and environments in a reactor, test specimens should be modified as much as possible to the real state of the fuel. Therefore, in order to consider the grid cell relaxation effects on the HFV tests, it is important to use cell sized or non-cell sized grids. The main focus of this study is to find out how the HFV characteristics such as amplitude and frequency are affected by grid cell relaxation. Three cases of the grid cell sized specimen which is nickel alloy were prepared and tested. Through the comparison of the test results, it could be concluded that HFV amplitudes show decreasing trend according to the grid cell relaxation in the case of nickel alloy grid. It is also possible to expect the tendency of grid cell relaxation of a zirconium alloy grid based on test results

  7. Scalar hairy black holes and solitons in asymptotically flat spacetimes

    International Nuclear Information System (INIS)

    Nucamendi, Ulises; Salgado, Marcelo

    2003-01-01

    A numerical analysis shows that the Einstein field equations allow static and spherically symmetric black hole solutions with scalar-field hair in asymptotically flat spacetimes. When regularity at the origin is imposed (i.e., in the absence of a horizon) globally regular scalar solitons are found. The asymptotically flat solutions are obtained provided that the scalar potential V(φ) of the theory is not positive semidefinite and such that its local minimum is also a zero of the potential, the scalar field settling asymptotically at that minimum. The configurations, although unstable under spherically symmetric linear perturbations, are regular and thus can serve as counterexamples to the no-scalar-hair conjecture

  8. Relaxation of helium levels excited by heavy ion impact: III.- Orientation by anisotropic relaxation of excited atoms in previously aligned states

    International Nuclear Information System (INIS)

    Chamoun, E.; Lombardi, M.; Carre, M.; Gaillard, M.L.

    1977-01-01

    In the last paper of this series devoted to relaxation phenomena in a low pressure cell of helium excited by an accelerated ion beam, experimental evidence is given for a new mechanism of transfer between alignment and orientation through anisotropic relaxation of initially aligned excited states. The theory predicting this effect is briefly outlined and then description is given of the exact experimental conditions to detect the circularly polarized component of the light emitted by the target excited in the 4 1 D level of He I by Na + impact [fr

  9. Many-body calculations of molecular electric polarizabilities in asymptotically complete basis sets

    Science.gov (United States)

    Monten, Ruben; Hajgató, Balázs; Deleuze, Michael S.

    2011-10-01

    The static dipole polarizabilities of Ne, CO, N2, F2, HF, H2O, HCN, and C2H2 (acetylene) have been determined close to the Full-CI limit along with an asymptotically complete basis set (CBS), according to the principles of a Focal Point Analysis. For this purpose the results of Finite Field calculations up to the level of Coupled Cluster theory including Single, Double, Triple, Quadruple and perturbative Pentuple excitations [CCSDTQ(P)] were used, in conjunction with suited extrapolations of energies obtained using augmented and doubly-augmented Dunning's correlation consistent polarized valence basis sets of improving quality. The polarizability characteristics of C2H4 (ethylene) and C2H6 (ethane) have been determined on the same grounds at the CCSDTQ level in the CBS limit. Comparison is made with results obtained using lower levels in electronic correlation, or taking into account the relaxation of the molecular structure due to an adiabatic polarization process. Vibrational corrections to electronic polarizabilities have been empirically estimated according to Born-Oppenheimer Molecular Dynamical simulations employing Density Functional Theory. Confrontation with experiment ultimately indicates relative accuracies of the order of 1 to 2%.

  10. Inverted hierarchy and asymptotic freedom in grand unified supersymmetric theories

    International Nuclear Information System (INIS)

    Aratyn, H.

    1983-01-01

    The interrelation between an inverted hierarchy mechanism and asymptotic freedom in supersymmetric theories is analyzed in two models for which we performed a detailed analysis of the effective potentials and effective couplings. We find it difficult to accommodate an inverted hierarchy together with asymptotic freedom for the matter-Yukawa couplings. (orig.)

  11. Effective action for composite operators and chiral symmetry breakdown in asymptotically free and non-asymptotically free gauge theories

    International Nuclear Information System (INIS)

    Gusynin, V.P.; Miranskij, V.A.

    1987-01-01

    An essential distinction in the relaization of the PCAC dynamics in asymptotically free and non-asymptotically free (with a non-trivial ultraviolet-stable fixed point) gauge theories is revealed. For the latter theories an analytical expressions for the condensate is obtained in the two-loop approximation and arguments of support of a soft behaviour at small distances of composite operators are given. The problem of factorizing the low-energy region for the Wess-Zumino-Witten action is discussed. Besides, the mass relations for pseudoscalar mesons in arbitrary Θ-sector are obtained in the first order in fermion bare masses and the impossibility for spontaneous P and CP-symmetries breaking in vector-like gauge theories at Θ=0 is shown

  12. Non-pionic effects in deuteron asymptotic observables

    International Nuclear Information System (INIS)

    Ballot, J.L.; Robilotta, M.R.

    1991-01-01

    It is well known that pion dynamics dominates deuteron asymptotic observables, especially η, the D/S ratio and Q, the quadrupole moment. A procedure has been discussed earlier that allows the unambiguous determination of the pion contribution to these observables as function of the pion-nucleon coupling constant. This problem is discussed in the framework of a specific model for the nucleon-nucleon interaction, namely the potential developed by the Tourreil, Rouben and Sprung. The contribution of non-pionic dynamics to deuteron asymptotic observables is investigated. It is shown that effects due to ρ and ω exchanges are negligible. (K.A.) 8 refs., 1 fig., 1 tab

  13. Black p-branes versus black holes in non-asymptotically flat Einstein-Yang-Mills theory

    Science.gov (United States)

    Habib Mazharimousavi, S.; Halilsoy, M.

    2016-09-01

    We present a class of non-asymptotically flat (NAF) charged black p-branes (BpB) with p-compact dimensions in higher-dimensional Einstein-Yang-Mills theory. Asymptotically the NAF structure manifests itself as an anti-de sitter spacetime. We determine the total mass/energy enclosed in a thin shell located outside the event horizon. By comparing the entropies of BpB with those of black holes in the same dimensions we derive transition criteria between the two types of black objects. Given certain conditions satisfied, our analysis shows that BpB can be considered excited states of black holes. An event horizon r+ versus charge square Q2 plot for the BpB reveals such a transition where r+ is related to the horizon radius rh of the black hole (BH) both with the common charge Q.

  14. New rigorous asymptotic theorems for inverse scattering amplitudes

    International Nuclear Information System (INIS)

    Lomsadze, Sh.Yu.; Lomsadze, Yu.M.

    1984-01-01

    The rigorous asymptotic theorems both of integral and local types obtained earlier and establishing logarithmic and in some cases even power correlations aetdeen the real and imaginary parts of scattering amplitudes Fsub(+-) are extended to the inverse amplitudes 1/Fsub(+-). One also succeeds in establishing power correlations of a new type between the real and imaginary parts, both for the amplitudes themselves and for the inverse ones. All the obtained assertions are convenient to be tested in high energy experiments when the amplitudes show asymptotic behaviour

  15. Vacuum energy in asymptotically flat 2 + 1 gravity

    Energy Technology Data Exchange (ETDEWEB)

    Miskovic, Olivera, E-mail: olivera.miskovic@pucv.cl [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Olea, Rodrigo, E-mail: rodrigo.olea@unab.cl [Departamento de Ciencias Físicas, Universidad Andres Bello, Sazié 2212, Piso 7, Santiago (Chile); Roy, Debraj, E-mail: roy.debraj@pucv.cl [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile)

    2017-04-10

    We compute the vacuum energy of three-dimensional asymptotically flat space based on a Chern–Simons formulation for the Poincaré group. The equivalent action is nothing but the Einstein–Hilbert term in the bulk plus half of the Gibbons–Hawking term at the boundary. The derivation is based on the evaluation of the Noether charges in the vacuum. We obtain that the vacuum energy of this space has the same value as the one of the asymptotically flat limit of three-dimensional anti-de Sitter space.

  16. Vacuum energy in asymptotically flat 2 + 1 gravity

    International Nuclear Information System (INIS)

    Miskovic, Olivera; Olea, Rodrigo; Roy, Debraj

    2017-01-01

    We compute the vacuum energy of three-dimensional asymptotically flat space based on a Chern–Simons formulation for the Poincaré group. The equivalent action is nothing but the Einstein–Hilbert term in the bulk plus half of the Gibbons–Hawking term at the boundary. The derivation is based on the evaluation of the Noether charges in the vacuum. We obtain that the vacuum energy of this space has the same value as the one of the asymptotically flat limit of three-dimensional anti-de Sitter space.

  17. Asymptotic behavior and Hamiltonian analysis of anti-de Sitter gravity coupled to scalar fields

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo; Zanelli, Jorge

    2007-01-01

    We examine anti-de Sitter gravity minimally coupled to a self-interacting scalar field in D>=4 dimensions when the mass of the scalar field is in the range m * 2 = 2 * 2 +l -2 . Here, l is the AdS radius, and m * 2 is the Breitenlohner-Freedman mass. We show that even though the scalar field generically has a slow fall-off at infinity which back reacts on the metric so as to modify its standard asymptotic behavior, one can still formulate asymptotic conditions (i) that are anti-de Sitter invariant; and (ii) that allows the construction of well-defined and finite Hamiltonian generators for all elements of the anti-de Sitter algebra. This requires imposing a functional relationship on the coefficients a, b that control the two independent terms in the asymptotic expansion of the scalar field. The anti-de Sitter charges are found to involve a scalar field contribution. Subtleties associated with the self-interactions of the scalar field as well as its gravitational back reaction, not discussed in previous treatments, are explicitly analyzed. In particular, it is shown that the fields develop extra logarithmic branches for specific values of the scalar field mass (in addition to the known logarithmic branch at the B-F bound)

  18. A study of internal energy relaxation in shocks using molecular dynamics based models

    International Nuclear Information System (INIS)

    Li, Zheng; Parsons, Neal; Levin, Deborah A.

    2015-01-01

    Recent potential energy surfaces (PESs) for the N 2 + N and N 2 + N 2 systems are used in molecular dynamics (MD) to simulate rates of vibrational and rotational relaxations for conditions that occur in hypersonic flows. For both chemical systems, it is found that the rotational relaxation number increases with the translational temperature and decreases as the rotational temperature approaches the translational temperature. The vibrational relaxation number is observed to decrease with translational temperature and approaches the rotational relaxation number in the high temperature region. The rotational and vibrational relaxation numbers are generally larger in the N 2 + N 2 system. MD-quasi-classical trajectory (QCT) with the PESs is also used to calculate the V-T transition cross sections, the collision cross section, and the dissociation cross section for each collision pair. Direct simulation Monte Carlo (DSMC) results for hypersonic flow over a blunt body with the total collision cross section from MD/QCT simulations, Larsen-Borgnakke with new relaxation numbers, and the N 2 dissociation rate from MD/QCT show a profile with a decreased translational temperature and a rotational temperature close to vibrational temperature. The results demonstrate that many of the physical models employed in DSMC should be revised as fundamental potential energy surfaces suitable for high temperature conditions become available

  19. An Enhanced Asymptotic Expansion for the Stability of Nonlinear Elastic Structures

    DEFF Research Database (Denmark)

    Christensen, Claus Dencker; Byskov, Esben

    2010-01-01

    A new, enhanced asymptotic expansion applicable to stability of structures made of nonlinear elastic materials is established. The method utilizes “hyperbolic” terms instead of the conventional polynomial terms, covers full kinematic nonlinearity and is applied to nonlinear elastic Euler columns...... with two different types of cross-section. Comparison with numerical results show that our expansion provides more accurate predictions of the behavior than usual expansions. The method is based on an extended version of the principle of virtual displacements that covers cases with auxiliary conditions...

  20. Asymptotic freedom and the symplectic and G2 groups

    International Nuclear Information System (INIS)

    Chaichian, M; Kolmakov, Yu. N.; Nelipa, N. F.

    1978-01-01

    It is shown that the symplectic Sp(4), Sp(6) and the exceptional G 2 gauge field theories with complete Spontaneous symmetry breaking through the Higgs mechanism are not asymptotically free. This, together with earlier results for other groups, hints at the existence of a general theorem according to which it would no longer be possible for asymptotic freedom to coexist with the absence of infrared divergences. (author)

  1. Mozart versus new age music: relaxation states, stress, and ABC relaxation theory.

    Science.gov (United States)

    Smith, Jonathan C; Joyce, Carol A

    2004-01-01

    Smith's (2001) Attentional Behavioral Cognitive (ABC) relaxation theory proposes that all approaches to relaxation (including music) have the potential for evoking one or more of 15 factor-analytically derived relaxation states, or "R-States" (Sleepiness, Disengagement, Rested / Refreshed, Energized, Physical Relaxation, At Ease/Peace, Joy, Mental Quiet, Childlike Innocence, Thankfulness and Love, Mystery, Awe and Wonder, Prayerfulness, Timeless/Boundless/Infinite, and Aware). The present study investigated R-States and stress symptom-patterns associated with listening to Mozart versus New Age music. Students (N = 63) were divided into three relaxation groups based on previously determined preferences. Fourteen listened to a 28-minute tape recording of Mozart's Eine Kleine Nachtmusik and 14 listened to a 28-minute tape of Steven Halpern's New Age Serenity Suite. Others (n = 35) did not want music and instead chose a set of popular recreational magazines. Participants engaged in their relaxation activity at home for three consecutive days for 28 minutes a session. Before and after each session, each person completed the Smith Relaxation States Inventory (Smith, 2001), a comprehensive questionnaire tapping 15 R-States as well as the stress states of somatic stress, worry, and negative emotion. Results revealed no differences at Session 1. At Session 2, those who listened to Mozart reported higher levels of At Ease/Peace and lower levels of Negative Emotion. Pronounced differences emerged at Session 3. Mozart listeners uniquely reported substantially higher levels of Mental Quiet, Awe and Wonder, and Mystery. Mozart listeners reported higher levels, and New Age listeners slightly elevated levels, of At Ease/Peace and Rested/Refreshed. Both Mozart and New Age listeners reported higher levels of Thankfulness and Love. In summary, those who listened to Mozart's Eine Kleine Nachtmusik reported more psychological relaxation and less stress than either those who listened to

  2. On Asymptotically Lacunary Statistical Equivalent Sequences of Order α in Probability

    Directory of Open Access Journals (Sweden)

    Işık Mahmut

    2017-01-01

    Full Text Available In this study, we introduce and examine the concepts of asymptotically lacunary statistical equivalent of order α in probability and strong asymptotically lacunary equivalent of order α in probability. We give some relations connected to these concepts.

  3. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  4. Polymers and Random graphs: Asymptotic equivalence to branching processes

    International Nuclear Information System (INIS)

    Spouge, J.L.

    1985-01-01

    In 1974, Falk and Thomas did a computer simulation of Flory's Equireactive RA/sub f/ Polymer model, rings forbidden and rings allowed. Asymptotically, the Rings Forbidden model tended to Stockmayer's RA/sub f/ distribution (in which the sol distribution ''sticks'' after gelation), while the Rings Allowed model tended to the Flory version of the RA/sub f/ distribution. In 1965, Whittle introduced the Tree and Pseudomultigraph models. We show that these random graphs generalize the Falk and Thomas models by incorporating first-shell substitution effects. Moreover, asymptotically the Tree model displays postgelation ''sticking.'' Hence this phenomenon results from the absence of rings and occurs independently of equireactivity. We also show that the Pseudomultigraph model is asymptotically identical to the Branching Process model introduced by Gordon in 1962. This provides a possible basis for the Branching Process model in standard statistical mechanics

  5. An Asymptotic Approach for the Elastodynamic Problem of a Plate under Impact Loading

    Directory of Open Access Journals (Sweden)

    Penelope Michalopoulou

    2010-01-01

    Full Text Available An approach is presented for analyzing the transient elastodynamic problem of a plate under an impact loading. The plate is considered to be in the form of a long strip under plane strain conditions. The loading is taken as a concentrated line force applied normal to the plate surface. It is assumed that this line force is suddenly applied and maintained thereafter (i.e., it is a Heaviside step function of time. Inertia effects are taken into consideration and the problem is treated exactly within the framework of elastodynamic theory. The approach is based on multiple Laplace transforms and on certain asymptotic arguments. In particular, the one-sided Laplace transform is applied to suppress time dependence and the two-sided Laplace transform to suppress the dependence upon a spatial variable (along the extent of the infinite strip. Exact inversions are then followed by invoking the asymptotic Tauber theorem and the Cagniard-deHoop technique. Various extensions of this basic analysis are also discussed.

  6. Systematic assignment of Feshbach resonances via an asymptotic bound state model

    NARCIS (Netherlands)

    Goosen, M.; Kokkelmans, SJ.J.M.F.

    2008-01-01

    We present an Asymptotic Bound state Model (ABM), which is useful to predict Feshbach resonances. The model utilizes asymptotic properties of the interaction potentials to represent coupled molecular wavefunctions. The bound states of this system give rise to Feshbach resonances, localized at the

  7. Asymptotic solving method for sea-air coupled oscillator ENSO model

    International Nuclear Information System (INIS)

    Zhou Xian-Chun; Yao Jing-Sun; Mo Jia-Qi

    2012-01-01

    The ENSO is an interannual phenomenon involved in the tropical Pacific ocean-atmosphere interaction. In this article, we create an asymptotic solving method for the nonlinear system of the ENSO model. The asymptotic solution is obtained. And then we can furnish weather forecasts theoretically and other behaviors and rules for the atmosphere-ocean oscillator of the ENSO. (general)

  8. A multigroup flux-limited asymptotic diffusion Fokker-Planck equation

    International Nuclear Information System (INIS)

    Liu Chengan

    1987-01-01

    A more perfrect flux-limited method is applied to combine with asymptotic diffusion theory of the radiation transpore, and the high peaked component in the scattering angle is treated with Fokker-Planck methods, thus the flux-limited asymptotic diffusion Fokker-Planck equation has been founded. Since the equation is of diffusion form, it retains the simplity and the convenience of the classical diffusion theory, and improves precision in describing radiation transport problems

  9. Asymptotic normalization coefficients and astrophysical factors

    International Nuclear Information System (INIS)

    Mukhamedzhanov, A.M.; Azhari, A.; Clark, H.L.; Gagliardi, C.A.; Lui, Y.-W.; Sattarov, A.; Trache, L.; Tribble, R.E.; Burjan, V.; Kroha, V.; Carstoiu, F.

    2000-01-01

    The S factor for the direct capture reaction 7 Be(p,γ) 8 B can be found at astrophysical energies from the asymptotic normalization coefficients (ANC's) which provide the normalization of the tails of the overlap functions for 8 B → 7 Be + p. Peripheral transfer reactions offer a technique to determine these ANC's. Using this technique, the 10 B( 7 Be, 8 B) 9 Be and 14 N( 7 Be, 8 B) 13 C reactions have been used to measure the asymptotic normalization coefficient for 7 Be(p, γ) 8 B. These results provide an indirect determination of S 17 (0). Analysis of the existing 9 Be(p, γ) 10 B experimental data within the framework of the R-matrix method demonstrates that experimentally measured ANC's can provide a reasonable determination of direct radiative capture rates. (author)

  10. Asymptotically spacelike warped anti-de Sitter spacetimes in generalized minimal massive gravity

    International Nuclear Information System (INIS)

    Setare, M R; Adami, H

    2017-01-01

    In this paper we show that warped AdS 3 black hole spacetime is a solution of the generalized minimal massive gravity (GMMG) and introduce suitable boundary conditions for asymptotically warped AdS 3 spacetimes. Then we find the Killing vector fields such that transformations generated by them preserve the considered boundary conditions. We calculate the conserved charges which correspond to the obtained Killing vector fields and show that the algebra of the asymptotic conserved charges is given as the semi direct product of the Virasoro algebra with U (1) current algebra. We use a particular Sugawara construction to reconstruct the conformal algebra. Thus, we are allowed to use the Cardy formula to calculate the entropy of the warped black hole. We demonstrate that the gravitational entropy of the warped black hole exactly coincides with what we obtain via Cardy’s formula. As we expect, the warped Cardy formula also gives us exactly the same result as we obtain from the usual Cardy’s formula. We calculate mass and angular momentum of the warped black hole and then check that obtained mass, angular momentum and entropy to satisfy the first law of the black hole mechanics. According to the results of this paper we believe that the dual theory of the warped AdS 3 black hole solution of GMMG is a warped CFT. (paper)

  11. Influence of phase transformations on the asymptotic residual stress distribution arising near a sharp V-notch tip

    International Nuclear Information System (INIS)

    Ferro, P

    2012-01-01

    In this work, the residual stress distribution induced by the solidification and cooling of a fusion zone in the vicinity of a sharp V-notch tip is investigated. The intensity of the residual asymptotic stress fields, quantified by the notch stress intensity factors, was studied for two different V-notch specimen geometries under generalized plane-strain conditions. In order to analyze the influence of phase transformations on the obtained results, simulations with and without the effects of phase transformation were carried out on ASTM SA 516 steel plates. Thanks to the possibilities of numerical modelling, additional analyses were performed without taking into account the transformation plasticity phenomenon. It was found that phase transformation effects (both volume change and transformation plasticity) have a great influence on the intensity and sign of the asymptotic stress fields at the sharp V-notch tips. This result is believed to be very important for the correct numerical determination (and future applications) of notch stress intensity factors resulting from asymptotic residual stress distributions induced by transient thermal loads. The analyses were performed with the finite element code SYSWELD. (paper)

  12. Asymptotic properties of a simple random motion

    International Nuclear Information System (INIS)

    Ravishankar, K.

    1988-01-01

    A random walker in R/sup N/ is considered. At each step the walker picks a point in R/sup N/ from a fixed finite set of destination points. Having chosen the point, the walker moves a fraction r (r < 1) of the distance toward the point along a straight line. Assuming that the successive destination points are chosen independently, it is shown that the asymptotic distribution of the walker's position has the same mean as the destination point distribution. An estimate is obtained for the fraction of time the walker stays within a ball centered at the mean value for almost every destination sequence. Examples show that the asymptotic distribution could have intricate structure

  13. Prolonged bone marrow T1-relaxation in patients with polycythemia vera

    DEFF Research Database (Denmark)

    Jensen, K E; Grube, T; Thomsen, C

    1988-01-01

    In vitro as well as in vivo studies have shown prolonged T1 relaxation times in patients with acute leukemia. The mechanism behind this finding is not known. In order to evaluate if this was specific for leukemia we examined eight patients with polycythemia vera, representing a condition with a r......In vitro as well as in vivo studies have shown prolonged T1 relaxation times in patients with acute leukemia. The mechanism behind this finding is not known. In order to evaluate if this was specific for leukemia we examined eight patients with polycythemia vera, representing a condition...

  14. Callan-Symanzik equation and asymptotic freedom in the Marr-Shimamoto model

    International Nuclear Information System (INIS)

    Scarfone, Leonard M.

    2010-01-01

    The exactly soluble nonrelativistic Marr-Shimamoto model was introduced in 1964 as an example of the Lee model with a propagator and a nontrivial vertex function. An exactly soluble relativistic version of this model, known as the Zachariasen model, has been found to be asymptotically free in terms of coupling constant renormalization at an arbitrary spacelike momentum and on the basis of exact solutions of the Gell-Mann-Low equations. This is accomplished with conventional cut-off regularization by setting up the Yukawa and Fermi coupling constants at Euclidean momenta in terms of on mass-shell couplings and then taking the asymptotic limit. In view of this background, it may be expected that an investigation of the nonrelativistic Marr-Shimamoto theory may also exhibit asymptotic freedom in view of its manifest mathematical similarity to that of the Zachariasen model. To prove this point, the present paper prefers to examine asymptotic freedom in the nonrelativistic Marr-Shimamoto theory using the powerful concepts of the renormalization group and the Callan-Symanzik equation, in conjunction with the specificity of dimensional regularization and on-shell renormalization. This approach is based on calculations of the Callan-Symanzik coefficients and determinations of the effective coupling constants. It is shown that the Marr-Shimamoto theory is asymptotically free for dimensions D 3 occurring in periodic intervals over the range of 0< D<27 of particular interest. This differs from the original Lee model which has been shown by several authors, using these same concepts, to be asymptotically free only for D<4.

  15. A study of nuclear relaxation to the electron non-Zeeman system

    International Nuclear Information System (INIS)

    Honten, J. van.

    1979-01-01

    An examination of the nuclear spin-lattice relaxation mechanism in a series of diluted copper-caesium Tutton salt crystals, containing different percentages of D 2 O in the waters of hydration, is described. Results of relaxation measurements are presented and a strong angular dependence is observed. It is proved, however, that under most experimental conditions applied, the bottleneck in the relaxation path is not the cross-relaxation but the thermal contact between the proton Zeeman system and the electron dipole-dipole interaction system. Hence the proton spin-lattice relaxation measurements have enabled determination of the time constant of this thermal contact. The microscopic coupling process which provides thermal contact, is a simultaneous transition of two electron spins and one proton spin. This so-called three-spin transition is described and calculations presented. Double resonance experiments are performed, where the resonance signal of deuterium or caesium spins is saturated and the effect on the proton resonance signal observed. (C.F.)

  16. Breathing and Relaxation

    Science.gov (United States)

    ... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

  17. The importance and use of asymptotic freedom beyond the leading order

    International Nuclear Information System (INIS)

    Duke, D.W.

    1979-05-01

    The theoretical and phenomenological importance of asymptotic freedom beyond the leading order is discussed. The two main topics are (1) the determination of the fundamental scale Λ, and (2) ambiguities in parton model definitions when using the higher order effects of asymptotic freedom. (author)

  18. Modeling broadband poroelastic propagation using an asymptotic approach

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, Donald W.

    2009-05-01

    An asymptotic method, valid in the presence of smoothly-varying heterogeneity, is used to derive a semi-analytic solution to the equations for fluid and solid displacements in a poroelastic medium. The solution is defined along trajectories through the porous medium model, in the manner of ray theory. The lowest order expression in the asymptotic expansion provides an eikonal equation for the phase. There are three modes of propagation, two modes of longitudinal displacement and a single mode of transverse displacement. The two longitudinal modes define the Biot fast and slow waves which have very different propagation characteristics. In the limit of low frequency, the Biot slow wave propagates as a diffusive disturbance, in essence a transient pressure pulse. Conversely, at low frequencies the Biot fast wave and the transverse mode are modified elastic waves. At intermediate frequencies the wave characteristics of the longitudinal modes are mixed. A comparison of the asymptotic solution with analytic and numerical solutions shows reasonably good agreement for both homogeneous and heterogeneous Earth models.

  19. Large-time asymptotic behaviour of solutions of non-linear Sobolev-type equations

    International Nuclear Information System (INIS)

    Kaikina, Elena I; Naumkin, Pavel I; Shishmarev, Il'ya A

    2009-01-01

    The large-time asymptotic behaviour of solutions of the Cauchy problem is investigated for a non-linear Sobolev-type equation with dissipation. For small initial data the approach taken is based on a detailed analysis of the Green's function of the linear problem and the use of the contraction mapping method. The case of large initial data is also closely considered. In the supercritical case the asymptotic formulae are quasi-linear. The asymptotic behaviour of solutions of a non-linear Sobolev-type equation with a critical non-linearity of the non-convective kind differs by a logarithmic correction term from the behaviour of solutions of the corresponding linear equation. For a critical convective non-linearity, as well as for a subcritical non-convective non-linearity it is proved that the leading term of the asymptotic expression for large times is a self-similar solution. For Sobolev equations with convective non-linearity the asymptotic behaviour of solutions in the subcritical case is the product of a rarefaction wave and a shock wave. Bibliography: 84 titles.

  20. Naturalness of asymptotically safe Higgs

    DEFF Research Database (Denmark)

    Pelaggi, Giulio M.; Sannino, Francesco; Strumia, Alessandro

    2017-01-01

    that the scalars can be lighter than Λ. Although we do not have an answer to whether the Standard Model hypercharge coupling growth toward a Landau pole at around Λ ~ 1040GeV can be tamed by non-perturbative asymptotic safety, our results indicate that such a possibility is worth exploring. In fact, if successful...

  1. Delay-Dependent Asymptotic Stability of Cohen-Grossberg Models with Multiple Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Xiaofeng Liao

    2007-01-01

    Full Text Available Dynamical behavior of a class of Cohen-Grossberg models with multiple time-varying delays is studied in detail. Sufficient delay-dependent criteria to ensure local and global asymptotic stabilities of the equilibrium of this network are derived by constructing suitable Lyapunov functionals. The obtained conditions are shown to be less conservative and restrictive than those reported in the known literature. Some numerical examples are included to demonstrate our results.

  2. Relaxation model of radiation-induced conductivity in polymers

    Science.gov (United States)

    Zhutayeva, Yu. R.; Khatipov, S. A.

    1999-05-01

    The paper suggests a relaxation model of radiation-induced conductivity (RIC) in polymers. According to the model, the transfer of charges generated in the polymer volume by ionizing radiation takes place with the participation of molecular relaxation processes. The mechanism of electron transport consists in the transfer of the charge directly between traps when they draw close to one another due to the rotation of macromolecule segments. The numerical solutions of the corresponding kinetic equations for different distribution functions Q( τ) of the times of molecular relaxation and for different functions of the probability P( τ, τ') of charge transfer in the `overlapping' regions of the diffusion spheres of the segments are analyzed. The relaxation model provides an explanation of the non-Arrhenius behavior of the RIC temperature dependence, the power dependence of RIC on the dose rate with a power index in the interval 0.5-1.0, the appearance of maxima in the curves of the RIC temporal dependence and their irreversible character in the region of large dose rates (more than 1 Gy/s). The model can be used for interpreting polymer RIC in conditions of kinetic mobility of macromolecules.

  3. Derivative analyticity relations and asymptotic energies

    International Nuclear Information System (INIS)

    Fischer, J.

    1976-01-01

    On the basis of general principles of the S-matrix theory theorems are derived showing that derivative analyticity relations analogous to those of Bronzen, Kane and Sukhatme hold at asymptotic energies if the high-energy limits of certain physical quantities exist

  4. Sleep, Stress & Relaxation: Rejuvenate Body & Mind

    Science.gov (United States)

    Sleep, Stress & Relaxation: Rejuvenate Body & Mind; Relieve Stress; best ways to relieve stress; best way to relieve stress; different ways to relieve stress; does smoking relieve stress; does tobacco relieve stress; how can I relieve stress; how can you relieve stress; how do I relieve stress; reduce stress; does smoking reduce stress; how can I reduce stress; how to reduce stress; reduce stress; reduce stress levels; reducing stress; smoking reduce stress; smoking reduces stress; stress reducing techniques; techniques to reduce stress; stress relief; best stress relief; natural stress relief; need stress relief; relief for stress; relief from stress; relief of stress; smoking and stress relief; smoking for stress relief; smoking stress relief; deal with stress; dealing with stress; dealing with anger; dealing with stress; different ways of dealing with stress; help dealing with stress; how to deal with anger; how to deal with stress; how to deal with stress when quitting smoking; stress management; free stress management; how can you manage stress; how do you manage stress; how to manage stress; manage stress; management of stress; management stress; managing stress; strategies for managing stress; coping with stress; cope with stress; copeing with stress; coping and stress; coping skills for stress; coping strategies for stress; coping strategies with stress; coping strategy for stress; coping with stress; coping with stress and anxiety; emotional health; emotional health; emotional health article; emotional health articles; deep relaxation; deep breathing relaxation techniques; deep muscle relaxation; deep relaxation; deep relaxation meditation; deep relaxation technique; deep relaxation techniques; meditation exercises; mindful exercises; mindful meditation exercises; online relaxation exercises; relaxation breathing exercises; relaxation exercise; relaxation exercises; stress relaxation; methods of relaxation for stress; relax stress; relax techniques stress

  5. Asymptotic theory of charge exchange for relativistic velocities and binding energies

    International Nuclear Information System (INIS)

    Demkov, Yu.N.; Ostrovskij, V.N.; Shevchenko, S.I.

    1983-01-01

    The asymptotic theory of charge exchange (ATCE) at a large shock parameter rho is applied to the case of relativistic velocities and binding energies. The charge exchange reaction (1+e)+2 → 1+(e+2), when an electron from the bound 1Ssub(1/2) state on one particle transforms to the 1Ssub(1/2) state on the other, is considered. Oasic features of the method are as follows: 1) the representation of the transition amplitude in the form of multidimensional integral over some hypersurface; 2) the use of the saddle-point method for calculating necessary multidimensional integrals; 3) the refinement of wave functions as compared with the case of the absence of the interaction. The ATCE (at rho → infinity) makes it possible to obtain analytical results whose accuracy is determined solely with the shock parameter rho. A basic term of charge exchange amplitude asymptotics for 1Ssub(1/2) → 1Ssub(1/2) transitions has been calculated. It is possible to consider the ATCE as a peculiar reference with which theoretical and experimental results can be compared as well as to use the ATCE as boundary conditions during numerical calculations

  6. Investigation of gender- and age-related preferences of men and women regarding lighting conditions for activation and relaxation

    Science.gov (United States)

    Schweitzer, S.; Schinagl, C.; Djuras, G.; Frühwirth, M.; Hoschopf, H.; Wagner, F.; Schulz, B.; Nemitz, W.; Grote, V.; Reidl, S.; Pritz, P.; Moser, M.; Wenzl, F. P.

    2016-09-01

    In recent years, LED lighting became an indispensable alternative to conventional lighting systems. Sophisticated solutions offer not only comfortable white light with a good color rendering. They also provide the possibility of changing illuminance and color temperature. Some systems even simulate daylight over the entire day, some including natural variations as due to clouds. Such systems are supposed to support the chronobiological needs of human and to have a positive effect on well-being, performance, sleep-quality and health. Lighting can also be used to support specific aims in a situation, like to improve productivity in activation or to support recreation in relaxation. Research regarding suitable light-settings for such situations and superordinate questions like their influence on well-being and health is still incomplete. We investigated the subjective preferences of men and women regarding light-settings for activation and relaxation. We supplied two rooms and four cubes with light sources that provide the possibility of tuning illuminance, color temperature and deviation from Plackian locus. More than 80 individuals - belonging to four groups differing in gender and age - were asked to imagine activating and recovering situations for which they should adjust suitable and pleasant lighting by tuning the above mentioned light properties. It was shown that there are clear differences in the lighting conditions preferred for these two situations. Also some combined gender- and age-specific differences became apparent.

  7. Asymptotical behaviour of pion electromagnetic form factor in QCD

    International Nuclear Information System (INIS)

    Efremov, A.V.; Radyushkin, A.V.

    1978-01-01

    In the framework of the renormalizable quantum field theory a new approach is developed to the investigation of asymptotical behaviour of two-particle bound state electromagnetic form factor. It is shown that the behaviour of the pion EM form factor in quantum chromodynamics at sufficiently large momentum transfers is controlled by the short-distance dynamics only. The formula is obtained which expresses the asymptotical behaviour of the pion form factor in terms of the fundamental constants of the theory

  8. L-citrulline supplementation reverses the impaired airway relaxation in neonatal rats exposed to hyperoxia

    Directory of Open Access Journals (Sweden)

    Sopi Ramadan B

    2012-08-01

    Full Text Available Abstract Background Hyperoxia is shown to impair airway relaxation via limiting L-arginine bioavailability to nitric oxide synthase (NOS and reducing NO production as a consequence. L-arginine can also be synthesized by L-citrulline recycling. The role of L-citrulline supplementation was investigated in the reversing of hyperoxia-induced impaired relaxation of rat tracheal smooth muscle (TSM. Methods Electrical field stimulation (EFS, 2–20 V-induced relaxation was measured under in vitro conditions in preconstricted tracheal preparations obtained from 12 day old rat pups exposed to room air or hyperoxia (>95% oxygen for 7 days supplemented with L-citrulline or saline (in vitro or in vivo. The role of the L-citrulline/L-arginine cycle under basal conditions was studied by incubation of preparations in the presence of argininosuccinate synthase (ASS inhibitor [α-methyl-D, L-aspartate, 1 mM] or argininosuccinate lyase inhibitor (ASL succinate (1 mM and/or NOS inhibitor [Nω-nitro-L-arginine methyl ester; 100 μM] with respect to the presence or absence of L-citrulline (2 mM. Results Hyperoxia impaired the EFS-induced relaxation of TSM as compared to room air control (p ; 0.5 ± 0.1% at 2 V to 50.6 ± 5.7% at 20 V in hyperoxic group: 0.7 ± 0.2 at 2 V to 80.0 ± 5.6% at 20 V in room air group. Inhibition of ASS or ASL, and L-citrulline supplementation did not affect relaxation responses under basal conditions. However, inhibition of NOS significantly reduced relaxation responses (p in vivo and in vitro also reversed the hyperoxia-impaired relaxation. The differences were significant (p ; 0.8 ± 0.3% at 2 V to 47.1 ± 4.1% at 20 V without L-citrulline; 0.9 ± 0.3% at 2 V to 68.2 ± 4.8% at 20 V with L-citrulline. Inhibition of ASS or ASL prevented this effect of L-citrulline. Conclusion The results indicate the presence of an L-citrulline/L-arginine cycle in the airways of rat pups

  9. Immersed Boundary-Lattice Boltzmann Method Using Two Relaxation Times

    Directory of Open Access Journals (Sweden)

    Kosuke Hayashi

    2012-06-01

    Full Text Available An immersed boundary-lattice Boltzmann method (IB-LBM using a two-relaxation time model (TRT is proposed. The collision operator in the lattice Boltzmann equation is modeled using two relaxation times. One of them is used to set the fluid viscosity and the other is for numerical stability and accuracy. A direct-forcing method is utilized for treatment of immersed boundary. A multi-direct forcing method is also implemented to precisely satisfy the boundary conditions at the immersed boundary. Circular Couette flows between a stationary cylinder and a rotating cylinder are simulated for validation of the proposed method. The method is also validated through simulations of circular and spherical falling particles. Effects of the functional forms of the direct-forcing term and the smoothed-delta function, which interpolates the fluid velocity to the immersed boundary and distributes the forcing term to fixed Eulerian grid points, are also examined. As a result, the following conclusions are obtained: (1 the proposed method does not cause non-physical velocity distribution in circular Couette flows even at high relaxation times, whereas the single-relaxation time (SRT model causes a large non-physical velocity distortion at a high relaxation time, (2 the multi-direct forcing reduces the errors in the velocity profile of a circular Couette flow at a high relaxation time, (3 the two-point delta function is better than the four-point delta function at low relaxation times, but worse at high relaxation times, (4 the functional form of the direct-forcing term does not affect predictions, and (5 circular and spherical particles falling in liquids are well predicted by using the proposed method both for two-dimensional and three-dimensional cases.

  10. Asymptotic Expansions - Methods and Applications

    International Nuclear Information System (INIS)

    Harlander, R.

    1999-01-01

    Different viewpoints on the asymptotic expansion of Feynman diagrams are reviewed. The relations between the field theoretic and diagrammatic approaches are sketched. The focus is on problems with large masses or large external momenta. Several recent applications also for other limiting cases are touched upon. Finally, the pros and cons of the different approaches are briefly discussed. (author)

  11. Centrally extended symmetry algebra of asymptotically Goedel spacetimes

    International Nuclear Information System (INIS)

    Compere, Geoffrey; Detournay, Stephane

    2007-01-01

    We define an asymptotic symmetry algebra for three-dimensional Goedel spacetimes supported by a gauge field which turns out to be the semi-direct sum of the diffeomorphisms on the circle with two loop algebras. A class of fields admitting this asymptotic symmetry algebra and leading to well-defined conserved charges is found. The covariant Poisson bracket of the conserved charges is then shown to be centrally extended to the semi-direct sum of a Virasoro algebra and two affine algebras. The subsequent analysis of three-dimensional Goedel black holes indicates that the Virasoro central charge is negative

  12. Deep inelastic scattering in an asymptotically free gauge theory

    International Nuclear Information System (INIS)

    Fujiwara, Tsutomu

    1977-01-01

    This paper reviews the success of the asymptotically free gauge theory which describes the deep inelastic lepton-hadron scattering. The asymptotically free gauge theory was discussed as well as the reason why the parton has the nature like free particles by the aid of the field theory. The asymptotically free gauge theory (AFGT) gives the prediction that the Bjorken scaling gives rise to logarithmic violation. The theory was applied to the exchange processes of single photon and two photons. First, this paper describes the approaches to the Bjorken scaling. The approaches are the discussion of the scaling law dependent on the model and the discussion of the scaling law independent of the model. The field theoretical treatment in described. This is called the method of the renormalization group introduced by Wilson. The asymptotically free gauge theory was formed on the basis of the Callan-Symanzik equation (CSE) and of the Weinberg's power counting theorem. The exact Bjorken scaling does not hold in the quantum field theory, at least there must be logarithmic violation. The pattern of the scaling violation cannot be clarified by the present data. Discussions concerning two gamma process are presented. The measurement of the photon-photon scattering process will give the judgement whether the prediction of the AFGT is correct or not. (Kato, T.)

  13. On iterative procedures of asymptotic inference

    NARCIS (Netherlands)

    K.O. Dzhaparidze (Kacha)

    1983-01-01

    textabstractAbstract  An informal discussion is given on performing an unconstrained maximization or solving non‐linear equations of statistics by iterative methods with the quadratic termination property. It is shown that if a miximized function, e.g. likelihood, is asymptotically quadratic, then

  14. Analysis of the kinetics of the fragile fracture process in Mo monocrystals in quasi-relaxation

    International Nuclear Information System (INIS)

    Tamayo Meza, Pedro; Bautista Godinez, Eric Gustavo; Yermishkin, Viacheslav

    2008-01-01

    The method of quasi-relaxation, generally known as the force relaxation method, has been widely applied in the study of elementary dislocational processes. It is essential for the study and analysis of thermoactivated mechanisms, for the determination of the energy of interaction between dislocations and inclusions, in the definition of the dislocational constants, to predict the development of creep, and even for the study of fracture kinetics. For the first time the use of the quasi-relaxation method for evaluating the fragile fracture tendency was presented in the work. However, as usually carried out, the use of mass specimens and the development of a considerable plastic deformation in the vertex of the crack-notch sample limits the possibilities for this method. Many studies analyze the theoretical aspects of the fracture process, and the obtention of reliable quantitative information about the behavior of the dislocation based on an analytical description of the process, and how and when it influences the conditions under which the final catastrophic fracture occurs. This work proposes a new method to analyze the effect of a tension concentrator on the surface of Mo monocrystal specimens. The relaxation of the force and the increase in the crack opening is related to the development of the plastic zone in its vertex with the help of the Irwin correction. During the relaxation, the crack-groove grows until it attains the length of the plastic zone. Specimens with and without force concentrators were tested in quasi-relaxation. The cracks appearing under these conditions are analyzed using a scanning electron microscopy (SEM). The crack appearing in the specimens under load conditions, whose development produced heavy force relaxation, allowed the force relaxation value to be defined and compared in the specimens with and without tension concentrators (au)

  15. Asymptotically stable phase synchronization revealed by autoregressive circle maps

    Science.gov (United States)

    Drepper, F. R.

    2000-11-01

    A specially designed of nonlinear time series analysis is introduced based on phases, which are defined as polar angles in spaces spanned by a finite number of delayed coordinates. A canonical choice of the polar axis and a related implicit estimation scheme for the potentially underlying autoregressive circle map (next phase map) guarantee the invertibility of reconstructed phase space trajectories to the original coordinates. The resulting Fourier approximated, invertibility enforcing phase space map allows us to detect conditional asymptotic stability of coupled phases. This comparatively general synchronization criterion unites two existing generalizations of the old concept and can successfully be applied, e.g., to phases obtained from electrocardiogram and airflow recordings characterizing cardiorespiratory interaction.

  16. Dynamic relaxation method for nonlinear buckling analysis of moderately thick FG cylindrical panels with various boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Golmakani, M. E.; Far, M. N. Sadraee; Moravej, M. [Dept. of Mechanical Engineering, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

    2016-12-15

    Using new approach proposed by Dynamic relaxation (DR) method, buckling analysis of moderately thick Functionally graded (FG) cylindrical panels subjected to axial compression is investigated for various boundary conditions. The mechanical properties of FG panel are assumed to vary continuously along the thickness direction by the simple rule of mixture and Mori-Tanaka model. The incremental form of nonlinear formulations are derived based on First-order shear deformation theory (FSDT) and large deflection von Karman equations. The DR method combined with the finite difference discretization technique is employed to solve the incremental form of equilibrium equations. The critical mechanical buckling load is determined based on compressive load-displacement curve by adding the incremental displacements in each load step to the displacements obtained from the previous ones. A detailed parametric study is carried out to investigate the influences of the boundary conditions, rule of mixture, grading index, radius-to-thickness ratio, length-to-radius ratio and panel angle on the mechanical buckling load. The results reveal that with increase of grading index the effect of radius-to-thickness ratio on the buckling load decreases. It is also observed that effect of distribution rules on the buckling load is dependent to the type of boundary conditions.

  17. The effects of progressive muscle relaxation and autogenic relaxation on young soccer players' mood states.

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi Ahmad Yusof, Hazwani

    2011-06-01

    This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players' mood states.

  18. Magnetism of a relaxed single atom vacancy in graphene

    Science.gov (United States)

    Wu, Yunyi; Hu, Yonghong; Xue, Li; Sun, Tieyu; Wang, Yu

    2018-04-01

    It has been suggested in literature that defects in graphene (e.g. absorbed atoms and vacancies) may induce magnetizations due to unpaired electrons. The nature of magnetism, i.e. ferromagnetic or anti-ferromagnetic, is dependent on a number of structural factors including locations of magnetic moments and lattice symmetry. In the present work we investigated the influence of a relaxed single atom vacancy in garphnene on magnetization which were obtained under different pinning boundary conditions, aiming to achieve a better understanding of the magnetic behaviors of graphene. Through first principles calculations, we found that major spin polarizations occur on atoms that deviate slightly from their original lattice positions, and pinning boundaries could also affect the relaxed positions of atoms and determine which atom(s) would become the main source(s) of total spin polarizations and magnetic moments. When the pinning boundary condition is free, a special non-magnetic and semi-conductive structure may be obtained, suggesting that magnetization should more readily occur under pinning boundary conditions.

  19. Asymptotic dynamics for the Cucker-Smale-type model with the Rayleigh friction

    International Nuclear Information System (INIS)

    Ha, Seung-Yeal; Ha, Taeyoung; Kim, Jong-Ho

    2010-01-01

    We study the asymptotic flocking dynamics for the Cucker-Smale-type second-order continuous-time dynamical system with the Rayleigh friction. For mean-field communications with a positive lower bound, we show that an asymptotic flocking occurs for any compactly supported initial configuration in a large coupling regime. In contrast, in a small coupling regime, an asymptotic flocking is possible for a restricted class of initial configurations near complete flocking states. We also present several numerical simulations and compare them with our analytical results.

  20. Asymptotic dynamics for the Cucker-Smale-type model with the Rayleigh friction

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Seung-Yeal [Department of Mathematical Sciences, Seoul National University, Seoul 151-747 (Korea, Republic of); Ha, Taeyoung; Kim, Jong-Ho, E-mail: syha@snu.ac.k, E-mail: tha@nims.re.k, E-mail: jhkim@nims.re.k [National Institute for Mathematical Sciences, 385-16, 3F Tower Koreana, Doryong-dong, Yuseong-gu, Daejeon, 305-340 (Korea, Republic of)

    2010-08-06

    We study the asymptotic flocking dynamics for the Cucker-Smale-type second-order continuous-time dynamical system with the Rayleigh friction. For mean-field communications with a positive lower bound, we show that an asymptotic flocking occurs for any compactly supported initial configuration in a large coupling regime. In contrast, in a small coupling regime, an asymptotic flocking is possible for a restricted class of initial configurations near complete flocking states. We also present several numerical simulations and compare them with our analytical results.

  1. Asymptotic formulae for solutions of the two-group integral neutron-transport equation

    International Nuclear Information System (INIS)

    Duracz, T.

    1976-01-01

    The steady-state, two-group integral neutron-transport equation is considered for two cases. First, for plane geometry, formulae for the asymptotic flux are obtained, under assumptions of homogeneous medium with isotropic scattering, extended to infinity (whole space and half-space), with sources vanishing at infinity as 0(esup(-IXI)). Next, for spherical geometry, the Milne problem is considered and formulae for the asymptotic flux are obtained. These formulae have the form of asymptotic expansions for small and large radii of the black sphere. (orig.) [de

  2. Stress relaxation analysis and irradiation creep and swelling in pressure tubes

    International Nuclear Information System (INIS)

    Beeston, J.M.; Burr, T.K.

    1979-01-01

    An analysis is presented of slit width test information on two pressure tubes that had been irradiated in test reactors. The analysis showed that differential swelling stresses and thermal stresses undergo relaxation. The mechanism responsible for the stress relaxation at temperatures less than 700 K was irradiation creep. Irradiation creep in thermal test reactor pressure tubes is evidently greater than it would be at equivalent conditions in fast reactors. The residual stresses observed in the slit width tests varied between 30 and 257 MPa and would act to reduce the operating stresses, thus allowing for increased service life of the tubes as compared with no stress relaxation

  3. The Asymptotic Safety Scenario in Quantum Gravity.

    Science.gov (United States)

    Niedermaier, Max; Reuter, Martin

    2006-01-01

    The asymptotic safety scenario in quantum gravity is reviewed, according to which a renormalizable quantum theory of the gravitational field is feasible which reconciles asymptotically safe couplings with unitarity. The evidence from symmetry truncations and from the truncated flow of the effective average action is presented in detail. A dimensional reduction phenomenon for the residual interactions in the extreme ultraviolet links both results. For practical reasons the background effective action is used as the central object in the quantum theory. In terms of it criteria for a continuum limit are formulated and the notion of a background geometry self-consistently determined by the quantum dynamics is presented. Self-contained appendices provide prerequisites on the background effective action, the effective average action, and their respective renormalization flows.

  4. Self similar asymptotics of the drift ion acoustic waves

    International Nuclear Information System (INIS)

    Taranov, V.B.

    2004-01-01

    A 3D model for the coupled drift and ion acoustic waves is considered. It is shown that self-similar solutions can exist due to the symmetry extension in asymptotic regimes. The form of these solutions is determined in the presence of the magnetic shear as well as in the shear less case. Some of the most symmetric exact solutions are obtained explicitly. In particular, solutions describing asymptotics of zonal flow interaction with monochromatic waves are presented and corresponding frequency shifts are determined

  5. Discrete Weighted Pseudo Asymptotic Periodicity of Second Order Difference Equations

    Directory of Open Access Journals (Sweden)

    Zhinan Xia

    2014-01-01

    Full Text Available We define the concept of discrete weighted pseudo-S-asymptotically periodic function and prove some basic results including composition theorem. We investigate the existence, and uniqueness of discrete weighted pseudo-S-asymptotically periodic solution to nonautonomous semilinear difference equations. Furthermore, an application to scalar second order difference equations is given. The working tools are based on the exponential dichotomy theory and fixed point theorem.

  6. Perturbed asymptotically linear problems

    OpenAIRE

    Bartolo, R.; Candela, A. M.; Salvatore, A.

    2012-01-01

    The aim of this paper is investigating the existence of solutions of some semilinear elliptic problems on open bounded domains when the nonlinearity is subcritical and asymptotically linear at infinity and there is a perturbation term which is just continuous. Also in the case when the problem has not a variational structure, suitable procedures and estimates allow us to prove that the number of distinct crtitical levels of the functional associated to the unperturbed problem is "stable" unde...

  7. Global asymptotic behavior in a Lotka–Volterra competition system with spatio-temporal delays

    International Nuclear Information System (INIS)

    Zhang, Jia-Fang; Chen, Heshan

    2014-01-01

    This paper is concerned with a Lotka–Volterra competition system with spatio-temporal delays. By using the linearization method, we show the local asymptotic behavior of the nonnegative steady-state solutions. Especially, the global asymptotic stability of the positive steady-state solution is investigated by the method of upper and lower solutions. The result of global asymptotic stability implies that the system has no nonconstant positive steady-state solution

  8. Asymptotic distribution of ∆AUC, NRIs, and IDI based on theory of U-statistics.

    Science.gov (United States)

    Demler, Olga V; Pencina, Michael J; Cook, Nancy R; D'Agostino, Ralph B

    2017-09-20

    The change in area under the curve (∆AUC), the integrated discrimination improvement (IDI), and net reclassification index (NRI) are commonly used measures of risk prediction model performance. Some authors have reported good validity of associated methods of estimating their standard errors (SE) and construction of confidence intervals, whereas others have questioned their performance. To address these issues, we unite the ∆AUC, IDI, and three versions of the NRI under the umbrella of the U-statistics family. We rigorously show that the asymptotic behavior of ∆AUC, NRIs, and IDI fits the asymptotic distribution theory developed for U-statistics. We prove that the ∆AUC, NRIs, and IDI are asymptotically normal, unless they compare nested models under the null hypothesis. In the latter case, asymptotic normality and existing SE estimates cannot be applied to ∆AUC, NRIs, or IDI. In the former case, SE formulas proposed in the literature are equivalent to SE formulas obtained from U-statistics theory if we ignore adjustment for estimated parameters. We use Sukhatme-Randles-deWet condition to determine when adjustment for estimated parameters is necessary. We show that adjustment is not necessary for SEs of the ∆AUC and two versions of the NRI when added predictor variables are significant and normally distributed. The SEs of the IDI and three-category NRI should always be adjusted for estimated parameters. These results allow us to define when existing formulas for SE estimates can be used and when resampling methods such as the bootstrap should be used instead when comparing nested models. We also use the U-statistic theory to develop a new SE estimate of ∆AUC. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Holography in asymptotically flat spacetimes and the BMS group

    International Nuclear Information System (INIS)

    Arcioni, Giovanni; Dappiaggi, Claudio

    2004-01-01

    In a previous paper (Arcioni G and Dappiaggi C 2003 Preprint hep-th/0306142) we have started to explore the holographic principle in the case of asymptotically flat spacetimes and analysed, in particular, different aspects of the Bondi-Metzner-Sachs (BMS) group, namely the asymptotic symmetry group of any asymptotically flat spacetime. We continue this investigation in this paper. Having in mind an S-matrix approach with future and past null infinity playing the role of holographic screens on which the BMS group acts, we connect the IR sectors of the gravitational field with the representation theory of the BMS group. We analyse the (complicated) mapping between bulk and boundary symmetries pointing out differences with respect to the anti-de Sitter (AdS)/CFT set up. Finally, we construct a BMS phase space and a free Hamiltonian for fields transforming with respect to BMS representations. The last step is supposed to be an explorative investigation of the boundary data living on the degenerate null manifold at infinity

  10. Asymptotic analysis of the Forward Search

    DEFF Research Database (Denmark)

    Johansen, Søren; Nielsen, Bent

    The Forward Search is an iterative algorithm concerned with detection of outliers and other unsuspected structures in data. This approach has been suggested, analysed and applied for regression models in the monograph Atkinson and Riani (2000). An asymptotic analysis of the Forward Search is made...

  11. An asymptotic problem in renewal theory

    NARCIS (Netherlands)

    Klamkin, M.S.; van Lint, J.H.

    1972-01-01

    A special problem in renewal theory is considered. The asymptotic behavior of the renewal function was studied by W. L. Smith. Here we show that his result with an exponentially small remainder term follows from a theorem of De Bruijn on Volterra integral equations.

  12. arXiv Phase structure of complete asymptotically free SU($N_c$) theories with quarks and scalar quarks

    CERN Document Server

    Hansen, Frederik F.; Langæble, Kasper; Mann, Robert B.; Sannino, Francesco; Steele, Tom G.; Wang, Zhi-Wei

    2018-03-21

    We determine the phase diagram of completely asymptotically free SU(Nc) gauge theories featuring Ns complex scalars and Nf Dirac quarks transforming according to the fundamental representation of the gauge group. The analysis is performed at the maximum known order in perturbation theory. We unveil a very rich dynamics and associated phase structure. Intriguingly, we discover that the completely asymptotically free conditions guarantee that the infrared dynamics displays long-distance conformality, and in a regime when perturbation theory is applicable. We conclude our analysis by determining the quantum corrected potential of the model and summarizing the possible patterns of radiative symmetry breaking. These models are of potential phenomenological interest as either elementary or composite ultraviolet finite extensions of the standard model.

  13. The Effects of Progressive Muscle Relaxation and Autogenic Relaxation on Young Soccer Players’ Mood States

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi@Ahmad Yusof, Hazwani

    2011-01-01

    Purpose This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. Methods Sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Results Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. Conclusion These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players’ mood states. PMID:22375225

  14. High-frequency asymptotics of the local vertex function. Algorithmic implementations

    Energy Technology Data Exchange (ETDEWEB)

    Tagliavini, Agnese; Wentzell, Nils [Institut fuer Theoretische Physik, Eberhard Karls Universitaet, 72076 Tuebingen (Germany); Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Li, Gang; Rohringer, Georg; Held, Karsten; Toschi, Alessandro [Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Taranto, Ciro [Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Andergassen, Sabine [Institut fuer Theoretische Physik, Eberhard Karls Universitaet, 72076 Tuebingen (Germany)

    2016-07-01

    Local vertex functions are a crucial ingredient of several forefront many-body algorithms in condensed matter physics. However, the full treatment of their frequency dependence poses a huge limitation to the numerical performance. A significant advancement requires an efficient treatment of the high-frequency asymptotic behavior of the vertex functions. We here provide a detailed diagrammatic analysis of the high-frequency asymptotic structures and their physical interpretation. Based on these insights, we propose a frequency parametrization, which captures the whole high-frequency asymptotics for arbitrary values of the local Coulomb interaction and electronic density. We present its algorithmic implementation in many-body solvers based on parquet-equations as well as functional renormalization group schemes and assess its validity by comparing our results for the single impurity Anderson model with exact diagonalization calculations.

  15. Physiological blunting during pregnancy extends to induced relaxation.

    Science.gov (United States)

    DiPietro, Janet A; Mendelson, Tamar; Williams, Erica L; Costigan, Kathleen A

    2012-01-01

    There is accumulating evidence that pregnancy is accompanied by hyporesponsivity to physical, cognitive, and psychological challenges. This study evaluates whether observed autonomic blunting extends to conditions designed to decrease arousal. Physiological and psychological responsivity to an 18-min guided imagery relaxation protocol in healthy pregnant women during the 32nd week of gestation (n=54) and non-pregnant women (n=28) was measured. Data collection included heart period (HP), respiratory sinus arrhythmia (RSA), tonic and phasic measures of skin conductance (SCL and NS-SCR), respiratory period (RP), and self-reported psychological relaxation. As expected, responses to the manipulation included increased HP, RSA, and RP and decreased SCL and NS-SCR, followed by post-manipulation recovery. However, responsivity was attenuated for all physiological measures except RP in pregnant women, despite no difference in self-reported psychological relaxation. Findings support non-specific blunting of physiological responsivity during pregnancy. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Global asymptotical ω-periodicity of a fractional-order non-autonomous neural networks.

    Science.gov (United States)

    Chen, Boshan; Chen, Jiejie

    2015-08-01

    We study the global asymptotic ω-periodicity for a fractional-order non-autonomous neural networks. Firstly, based on the Caputo fractional-order derivative it is shown that ω-periodic or autonomous fractional-order neural networks cannot generate exactly ω-periodic signals. Next, by using the contraction mapping principle we discuss the existence and uniqueness of S-asymptotically ω-periodic solution for a class of fractional-order non-autonomous neural networks. Then by using a fractional-order differential and integral inequality technique, we study global Mittag-Leffler stability and global asymptotical periodicity of the fractional-order non-autonomous neural networks, which shows that all paths of the networks, starting from arbitrary points and responding to persistent, nonconstant ω-periodic external inputs, asymptotically converge to the same nonconstant ω-periodic function that may be not a solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. The fourth-order non-linear sigma models and asymptotic freedom in four dimensions

    International Nuclear Information System (INIS)

    Buchbinder, I.L.; Ketov, S.V.

    1991-01-01

    Starting with the most general Lagrangian of the fourth-order non-linear sigma model in four space-time dimensions, we calculate the one-loop, on-shell ultra-violet-divergent part of the effective action. The formalism is based on the background field method and the generalised Schwinger-De Witt technique. The multiplicatively renormalisable case is investigated in some detail. The renormalisation group equations are obtained, and the conditions for a realisation of asymptotic freedom are considered. (orig.)

  18. Asymptotic symmetries on the Kerr-Newman horizon without the anomaly of diffeomorphism invariance

    International Nuclear Information System (INIS)

    Koga, Jun-ichirou

    2008-01-01

    We analyze asymptotic symmetries on the Killing horizon of the four-dimensional Kerr-Newman black hole. We first derive the asymptotic Killing vectors on the Killing horizon, which describe the asymptotic symmetries, and find that the general form of these asymptotic Killing vectors is the universal one possessed by arbitrary Killing horizons. We then construct the phase space associated with the asymptotic symmetries. It is shown that the phase space of an extreme black hole either has the size comparable with a non-extreme black hole, or is small enough to exclude degeneracy, depending on whether or not the global structure of a Killing horizon particular to an extreme black hole is respected. We also show that the classical central charge in the Poisson brackets algebra of these asymptotic symmetries vanishes, which implies that there is not an anomaly of diffeomorphism invariance. By taking into account other results in the literature, we argue that the vanishing central charge on a black hole horizon, in an effective theory, looks consistent with the thermal feature of a black hole. We furthermore argue that the vanishing central charge implies that there are sufficiently many classical configurations that constitute a single macroscopic state, while these configurations are distinguished physically

  19. Dissipation and the relaxation to equilibrium

    International Nuclear Information System (INIS)

    Evans, Denis J; Williams, Stephen R; Searles, Debra J

    2009-01-01

    Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium

  20. Selected asymptotic methods with applications to electromagnetics and antennas

    CERN Document Server

    Fikioris, George; Bakas, Odysseas N

    2013-01-01

    This book describes and illustrates the application of several asymptotic methods that have proved useful in the authors' research in electromagnetics and antennas. We first define asymptotic approximations and expansions and explain these concepts in detail. We then develop certain prerequisites from complex analysis such as power series, multivalued functions (including the concepts of branch points and branch cuts), and the all-important gamma function. Of particular importance is the idea of analytic continuation (of functions of a single complex variable); our discussions here include som

  1. Asymptotic inverse periods of reflected reactors above prompt critical

    International Nuclear Information System (INIS)

    Spriggs, G.D.; Busch, R.D.

    1995-01-01

    It is commonly assumed that the kinetic behavior of reflected and unreflected reactors is identical. In particular, it is often accepted that a given reactivity change in either type of system will result in an identical asymptotic inverse period. This is generally true for reactivities below prompt critical. For reactivities above prompt critical, however, the asymptotic inverse period can vary in a highly nonlinear fashion with system reactivity depending on the reflector return fraction, the neutron lifetime in the core, and the neutron lifetime in the reflector

  2. Asymptotic expansion of unsteady gravity flow of a power-law fluid ...

    African Journals Online (AJOL)

    We present a paper on the asymptotic expansion of unsteady non-linear rheological effects of a power-law fluid under gravity. The fluid flows through a porous medium. The asymptotic expansion is employed to obtain solution of the nonlinear problem. The results show the existence of traveling waves. It is assumed that the ...

  3. Asymptotic adaptive bipartite entanglement-distillation protocol

    International Nuclear Information System (INIS)

    Hostens, Erik; Dehaene, Jeroen; De Moor, Bart

    2006-01-01

    We present an asymptotic bipartite entanglement-distillation protocol that outperforms all existing asymptotic schemes. This protocol is based on the breeding protocol with the incorporation of two-way classical communication. Like breeding, the protocol starts with an infinite number of copies of a Bell-diagonal mixed state. Breeding can be carried out as successive stages of partial information extraction, yielding the same result: one bit of information is gained at the cost (measurement) of one pure Bell state pair (ebit). The basic principle of our protocol is at every stage to replace measurements on ebits by measurements on a finite number of copies, whenever there are two equiprobable outcomes. In that case, the entropy of the global state is reduced by more than one bit. Therefore, every such replacement results in an improvement of the protocol. We explain how our protocol is organized as to have as many replacements as possible. The yield is then calculated for Werner states

  4. Integrable theories that are asymptotically CFT

    CERN Document Server

    Evans, J M; Jonathan M Evans; Timothy J Hollowood

    1995-01-01

    A series of sigma models with torsion are analysed which generate their mass dynamically but whose ultra-violet fixed points are non-trivial conformal field theories -- in fact SU(2) WZW models at level k. In contrast to the more familiar situation of asymptotically free theories in which the fixed points are trivial, the sigma models considered here may be termed ``asymptotically CFT''. These theories have previously been conjectured to be quantum integrable; we confirm this by proposing a factorizable S-matrix to describe their infra-red behaviour and then carrying out a stringent test of this proposal. The test involves coupling the theory to a conserved charge and evaluating the response of the free-energy both in perturbation theory to one loop and directly from the S-matrix via the Thermodynamic Bethe Ansatz with a chemical potential at zero temperature. Comparison of these results provides convincing evidence in favour of the proposed S-matrix; it also yields the universal coefficients of the beta-func...

  5. Multiplicity of Solutions for a Class of Fourth-Order Elliptic Problems with Asymptotically Linear Term

    Directory of Open Access Journals (Sweden)

    Qiong Liu

    2012-01-01

    Full Text Available We study the following fourth-order elliptic equations: Δ2+Δ=(,,∈Ω,=Δ=0,∈Ω, where Ω⊂ℝ is a bounded domain with smooth boundary Ω and (, is asymptotically linear with respect to at infinity. Using an equivalent version of Cerami's condition and the symmetric mountain pass lemma, we obtain the existence of multiple solutions for the equations.

  6. Model Hadron asymptotic behaviour

    International Nuclear Information System (INIS)

    Kralchevsky, P.; Nikolov, A.

    1983-01-01

    The work is devoted to the problem of solving a set of asymptotic equations describing the model hardon interaction. More specifically an interactive procedure consisting of two stages is proposed and the first stage is exhaustively studied here. The principle of contracting transformations has been applied for this purpose. Under rather general and natural assumptions, solutions in a series of metric spaces suitable for physical applications have been found. For each of these spaces a solution with unique definiteness is found. (authors)

  7. The BFKL high energy asymptotic in the next-to-leading approximation

    International Nuclear Information System (INIS)

    Levin, Eugene

    1999-01-01

    We discuss the high energy asymptotic in the next-to-leading (NLO) BFKL equation. We find a general solution for the Green functions and consider two properties of the NLO BFKL kernel: running QCD coupling and large NLO corrections to the conformal part of the kernel. Both these effects lead to Regge-BFKL asymptotic only in the limited range of energy (y = ln(s/qq 0 ) ≤ (α S ) ((-5)/(3)) ) and change the energy behaviour of the amplitude for higher values of energy. We confirm the oscillation in the total cross section found by D.A. Ross [SHEP-98-06, hep-ph/9804332] in the NLO BFKL asymptotic, which shows that the NLO BFKL has a serious pathology

  8. The Conditional Entropy Power Inequality for Bosonic Quantum Systems

    DEFF Research Database (Denmark)

    de Palma, Giacomo; Trevisan, Dario

    2018-01-01

    We prove the conditional Entropy Power Inequality for Gaussian quantum systems. This fundamental inequality determines the minimum quantum conditional von Neumann entropy of the output of the beam-splitter or of the squeezing among all the input states where the two inputs are conditionally...... independent given the memory and have given quantum conditional entropies. We also prove that, for any couple of values of the quantum conditional entropies of the two inputs, the minimum of the quantum conditional entropy of the output given by the conditional Entropy Power Inequality is asymptotically...... achieved by a suitable sequence of quantum Gaussian input states. Our proof of the conditional Entropy Power Inequality is based on a new Stam inequality for the quantum conditional Fisher information and on the determination of the universal asymptotic behaviour of the quantum conditional entropy under...

  9. Asymptotic mass degeneracies in conformal field theories

    International Nuclear Information System (INIS)

    Kani, I.; Vafa, C.

    1990-01-01

    By applying a method of Hardy and Ramanujan to characters of rational conformal field theories, we find an asymptotic expansion for degeneracy of states in the limit of large mass which is exact for strings propagating in more than two uncompactified space-time dimensions. Moreover we explore how the rationality of the conformal theory is reflected in the degeneracy of states. We also consider the one loop partition function for strings, restricted to physical states, for arbitrary (irrational) conformal theories, and obtain an asymptotic expansion for it in the limit that the torus degenerates. This expansion depends only on the spectrum of (physical and unphysical) relevant operators in the theory. We see how rationality is consistent with the smoothness of mass degeneracies as a function of moduli. (orig.)

  10. The Asymptotic Safety Scenario in Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Niedermaier Max

    2006-12-01

    Full Text Available The asymptotic safety scenario in quantum gravity is reviewed, according to which a renormalizable quantum theory of the gravitational field is feasible which reconciles asymptotically safe couplings with unitarity. The evidence from symmetry truncations and from the truncated flow of the effective average action is presented in detail. A dimensional reduction phenomenon for the residual interactions in the extreme ultraviolet links both results. For practical reasons the background effective action is used as the central object in the quantum theory. In terms of it criteria for a continuum limit are formulated and the notion of a background geometry self-consistently determined by the quantum dynamics is presented. Self-contained appendices provide prerequisites on the background effective action, the effective average action, and their respective renormalization flows.

  11. A model problem for estimation of moving-film time relaxation at sudden change of boundary conditions

    Science.gov (United States)

    Smirnovsky, Alexander A.; Eliseeva, Viktoria O.

    2018-05-01

    The study of the film flow occurred under the influence of a gas slug flow is of definite interest in heat and mass transfer during the motion of a coolant in the second circuit of a nuclear water-water reactor. Thermohydraulic codes are usually used for analysis of the such problems in which the motion of the liquid film and the vapor is modeled on the basis of a one-dimensional balance equations. Due to a greater inertia of the liquid film motion, film flow parameters changes with a relaxation compared with gas flow. We consider a model problem of film flow under the influence of friction from gas slug flow neglecting such effects as wave formation, droplet breakage and deposition on the film surface, evaporation and condensation. Such a problem is analogous to the well-known problems of Couette and Stokes flows. An analytical solution has been obtained for laminar flow. Numerical RANS-based simulation of turbulent flow was performed using OpenFOAM. It is established that the relaxation process is almost self-similar. This fact opens a possibility of obtaining valuable correlations for the relaxation time.

  12. Nonmaxwell relaxation in disordered media: Physical mechanisms and fractional relaxation equations

    International Nuclear Information System (INIS)

    Arkhincheev, V.E.

    2004-12-01

    The problem of charge relaxation in disordered systems has been solved. It is shown, that due to the inhomogeneity of the medium the charge relaxation has a non-Maxwell character. The two physical mechanisms of a such behavior have been founded. The first one is connected with the 'fractality' of conducting ways. The second mechanism of nonexponential non-Maxwell behavior is connected with the frequency dispersion of effective conductivity of heterogeneous medium, initially consisting of conducting phases without dispersion. The new generalized relaxation equations in the form of fractional temporal integro-differential equations are deduced. (author)

  13. State of health assessment for lithium batteries based on voltage–time relaxation measure

    International Nuclear Information System (INIS)

    Baghdadi, Issam; Briat, Olivier; Gyan, Philippe; Vinassa, Jean Michel

    2016-01-01

    Highlights: • Calendar aging under different storage conditions for three different battery technologies studied. • Two scenarios of aging under power cycling at two different temperatures investigated for one battery technology. • Relaxation profile of battery voltage just after full charge is highly correlated to aging. • Linear dependence between just after charge open circuit voltage and remaining capacity demonstrated. • No computational method and direct prediction of battery state of health or remaining capacity. - Abstract: The performance of lithium batteries degrades over time. The degradation rate strongly depends on stress conditions during use and even at rest. Thus, accurate and rapid diagnosis of battery state of health (SOH) is necessary for electric vehicle manufacturers to manage their vehicle fleets and warranties. This paper demonstrates a simple method for assessing SOH related to battery energy capability (SOH E ). The presented method is based on the monitoring of U relax over aging. U relax is the open-circuit voltage of the battery measured after full charging and 30 min of rest. A linear dependence between U relax and remaining capacity is noted. This correlation is demonstrated for three different commercial battery technologies (different chemistries) aged under different calendar and power cycling aging conditions. It was determined that the difference between two U relax voltages measured at two different aging states is proportional to SOH E decay. The mean error of the linear model is less than 2% for certain cases. This method could also be a highly useful and rapid tool for a complete battery pack diagnosis.

  14. A modified homogeneous relaxation model for CO2 two-phase flow in vapour ejector

    International Nuclear Information System (INIS)

    Haida, M.; Palacz, M.; Smolka, J.; Nowak, A. J.; Hafner, A.; Banasiak, K.

    2016-01-01

    In this study, the homogenous relaxation model (HRM) for CO 2 flow in a two-phase ejector was modified in order to increase the accuracy of the numerical simulations The two- phase flow model was implemented on the effective computational tool called ejectorPL for fully automated and systematic computations of various ejector shapes and operating conditions. The modification of the HRM was performed by a change of the relaxation time and the constants included in the relaxation time equation based on the experimental result under the operating conditions typical for the supermarket refrigeration system. The modified HRM was compared to the HEM results, which were performed based on the comparison of motive nozzle and suction nozzle mass flow rates. (paper)

  15. A modified homogeneous relaxation model for CO2 two-phase flow in vapour ejector

    Science.gov (United States)

    Haida, M.; Palacz, M.; Smolka, J.; Nowak, A. J.; Hafner, A.; Banasiak, K.

    2016-09-01

    In this study, the homogenous relaxation model (HRM) for CO2 flow in a two-phase ejector was modified in order to increase the accuracy of the numerical simulations The two- phase flow model was implemented on the effective computational tool called ejectorPL for fully automated and systematic computations of various ejector shapes and operating conditions. The modification of the HRM was performed by a change of the relaxation time and the constants included in the relaxation time equation based on the experimental result under the operating conditions typical for the supermarket refrigeration system. The modified HRM was compared to the HEM results, which were performed based on the comparison of motive nozzle and suction nozzle mass flow rates.

  16. On the asymptotic solution to a class of linear integral equations

    International Nuclear Information System (INIS)

    Gautesen, A.K.

    1988-01-01

    The authors consider Fredholm integral equations of the first kind whose kernels are a function of the difference between two points times a large parameter. Conditions on the kernel are stated in terms of a function corresponding to a Wiener-Hopf factorization of the Fourier transform of the kernel. They give the complete asymptotic expansions of the solution to the integral equations. As applications of the author's results, the author considers the steady-state, acoustical scattering of a plane wave by both a hard strip and a soft strip. The author's results are uniform with respect to the direction of incidence

  17. Applications of Asymptotic Sampling on High Dimensional Structural Dynamic Problems

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Nielsen, Søren R.K.; Bucher, Christian

    2011-01-01

    The paper represents application of the asymptotic sampling on various structural models subjected to random excitations. A detailed study on the effect of different distributions of the so-called support points is performed. This study shows that the distribution of the support points has consid...... dimensional reliability problems in structural dynamics.......The paper represents application of the asymptotic sampling on various structural models subjected to random excitations. A detailed study on the effect of different distributions of the so-called support points is performed. This study shows that the distribution of the support points has...... is minimized. Next, the method is applied on different cases of linear and nonlinear systems with a large number of random variables representing the dynamic excitation. The results show that asymptotic sampling is capable of providing good approximations of low failure probability events for very high...

  18. Asymptotic near freedom

    International Nuclear Information System (INIS)

    Bailin, D.

    1974-01-01

    It is proved that the characteristic power deviations from scaling of the theories which are not asymptotically free should be detectable in the N.A.L. muon experiments. The Yukawa theories here considered have SU(3) non-singlet structure function moments varying as a power of -q 2 , namely (-q 2 ) at power -p. The maximum value of p is determined to be 2/3:SU3 and 1:SU2. The outstanding question is whether the Yukawa theories considered do in fact have fixed points satisfying the inequalities, and thus simultaneous (non-trivial) zeroes of β(g) and β(lambda) have to be found

  19. Group hypnotherapy versus group relaxation for smoking cessation: an RCT study protocol.

    Science.gov (United States)

    Dickson-Spillmann, Maria; Kraemer, Thomas; Rust, Kristina; Schaub, Michael

    2012-04-04

    A significant number of smokers would like to stop smoking. Despite the demonstrated efficacy of pharmacological smoking cessation treatments, many smokers are unwilling to use them; however, they are inclined to try alternative methods. Hypnosis has a long-standing reputation in smoking cessation therapy, but its efficacy has not been scientifically proven. We designed this randomised controlled trial to evaluate the effects of group hypnosis as a method for smoking cessation, and we will compare the results of group hypnosis with group relaxation. This is a randomised controlled trial (RCT) to compare the efficacy of a single session of hypnosis with that of relaxation performed in groups of 8-15 smokers. We intend to include at least 220 participants in our trial. The inclusion criteria include smoking at least 5 cigarettes per day, not using other cessation methods and being willing to quit smoking. The intervention is performed by a trained hypnotist/relaxation therapist. Both groups first receive 40 min of mental preparation that is based on motivational interviewing. Then, a state of deep relaxation is induced in the hypnosis condition, and superficial relaxation is induced in the control condition. Suggestions are made in the hypnosis condition that aim to switch the mental self-image of the participants from that of smokers to that of non-smokers. Each intervention lasts for 40 min. The participants also complete questionnaires that assess their smoking status and symptoms of depression and anxiety at baseline, 2 weeks and 6 months post-intervention. In addition, saliva samples are collected to assess cotinine levels at baseline and at 6 months post-intervention. We also assess nicotine withdrawal symptoms at 2 weeks post-intervention. To the best of our knowledge, this RCT is the first to test the efficacy of group hypnosis versus group relaxation. Issues requiring discussion in the outcome paper include the lack of standardisation of hypnotic

  20. Supersymmetric asymptotic safety is not guaranteed

    DEFF Research Database (Denmark)

    Intriligator, Kenneth; Sannino, Francesco

    2015-01-01

    in supersymmetric theories, and use unitarity bounds, and the a-theorem, to rule it out in broad classes of theories. The arguments apply without assuming perturbation theory. Therefore, the UV completion of a non-asymptotically free susy theory must have additional, non-obvious degrees of freedom, such as those...

  1. Generalized heat kernel coefficients for a new asymptotic expansion

    International Nuclear Information System (INIS)

    Osipov, Alexander A.; Hiller, Brigitte

    2003-01-01

    The method which allows for asymptotic expansion of the one-loop effective action W = lndetA is formulated. The positively defined elliptic operator A = U + M2 depends on the external classical fields taking values in the Lie algebra of the internal symmetry group G. Unlike the standard method of Schwinger - DeWitt, the more general case with the nongenerate mass matrix M = diag(m1, m2, ...) is considered. The first coefficients of the new asymptotic series are calculated and their relationship with the Seeley - DeWitt coefficients is clarified

  2. Global Asymptotic Stability of Switched Neural Networks with Delays

    Directory of Open Access Journals (Sweden)

    Zhenyu Lu

    2015-01-01

    Full Text Available This paper investigates the global asymptotic stability of a class of switched neural networks with delays. Several new criteria ensuring global asymptotic stability in terms of linear matrix inequalities (LMIs are obtained via Lyapunov-Krasovskii functional. And here, we adopt the quadratic convex approach, which is different from the linear and reciprocal convex combinations that are extensively used in recent literature. In addition, the proposed results here are very easy to be verified and complemented. Finally, a numerical example is provided to illustrate the effectiveness of the results.

  3. Asymptotic analysis of spatial discretizations in implicit Monte Carlo

    International Nuclear Information System (INIS)

    Densmore, Jeffery D.

    2009-01-01

    We perform an asymptotic analysis of spatial discretizations in Implicit Monte Carlo (IMC). We consider two asymptotic scalings: one that represents a time step that resolves the mean-free time, and one that corresponds to a fixed, optically large time step. We show that only the latter scaling results in a valid spatial discretization of the proper diffusion equation, and thus we conclude that IMC only yields accurate solutions when using optically large spatial cells if time steps are also optically large. We demonstrate the validity of our analysis with a set of numerical examples.

  4. Asymptotic properties of spherically symmetric, regular and static solutions to Yang-Mills equations

    International Nuclear Information System (INIS)

    Cronstrom, C.

    1987-01-01

    In this paper the author discusses the asymptotic properties of solutions to Yang-Mills equations with the gauge group SU(2), for spherically symmetric, regular and static potentials. It is known, that the pure Yang-Mills equations cannot have nontrivial regular solutions which vanish rapidly at space infinity (socalled finite energy solutions). So, if regular solutions exist, they must have non-trivial asymptotic properties. However, if the asymptotic behaviour of the solutions is non-trivial, then the fact must be explicitly taken into account in constructing the proper action (and energy) for the theory. The elucidation of the appropriate surface correction to the Yang-Mills action (and hence the energy-momentum tensor density) is one of the main motivations behind the present study. In this paper the author restricts to the asymptotic behaviour of the static solutions. It is shown that this asymptotic behaviour is such that surface corrections (at space-infinity) are needed in order to obtain a well-defined (classical) theory. This is of relevance in formulating a quantum Yang-Mills theory

  5. Evolutionary Pseudo-Relaxation Learning Algorithm for Bidirectional Associative Memory

    Institute of Scientific and Technical Information of China (English)

    Sheng-Zhi Du; Zeng-Qiang Chen; Zhu-Zhi Yuan

    2005-01-01

    This paper analyzes the sensitivity to noise in BAM (Bidirectional Associative Memory), and then proves the noise immunity of BAM relates not only to the minimum absolute value of net inputs (MAV) but also to the variance of weights associated with synapse connections. In fact, it is a positive monotonically increasing function of the quotient of MAV divided by the variance of weights. Besides, the performance of pseudo-relaxation method depends on learning parameters (λ and ζ), but the relation of them is not linear. So it is hard to find a best combination of λ and ζ which leads to the best BAM performance. And it is obvious that pseudo-relaxation is a kind of local optimization method, so it cannot guarantee to get the global optimal solution. In this paper, a novel learning algorithm EPRBAM (evolutionary psendo-relaxation learning algorithm for bidirectional association memory) employing genetic algorithm and pseudo-relaxation method is proposed to get feasible solution of BAM weight matrix. This algorithm uses the quotient as the fitness of each individual and employs pseudo-relaxation method to adjust individual solution when it does not satisfy constraining condition any more after genetic operation. Experimental results show this algorithm improves noise immunity of BAM greatly. At the same time, EPRBAM does not depend on learning parameters and can get global optimal solution.

  6. Asymptotic bounded consensus tracking of double-integrator multi-agent systems with bounded-jerk target based on sampled-data without velocity measurements

    International Nuclear Information System (INIS)

    Wu Shuang-Shuang; Wu Zhi-Hai; Peng Li; Xie Lin-Bo

    2017-01-01

    This paper investigates asymptotic bounded consensus tracking (ABCT) of double-integrator multi-agent systems (MASs) with an asymptotically-unbounded-acceleration and bounded-jerk target (AUABJT) available to partial agents based on sampled-data without velocity measurements. A sampled-data consensus tracking protocol (CTP) without velocity measurements is proposed to guarantee that double-integrator MASs track an AUABJT available to only partial agents. The eigenvalue analysis method together with the augmented matrix method is used to obtain the necessary and sufficient conditions for ABCT. A numerical example is provided to illustrate the effectiveness of theoretical results. (paper)

  7. Asymptotic equivalence of neutron diffusion and transport in time-independent reactor systems

    International Nuclear Information System (INIS)

    Borysiewicz, M.; Mika, J.; Spiga, G.

    1982-01-01

    Presented in this paper is the asymptotic analysis of the time-independent neutron transport equation in the second-order variational formulation. The small parameter introduced into the equation is an estimate of the ratio of absorption and leakage to scattering in the system considered. When the ratio tends to zero, the weak solution to the transport problem tends to the weak solution of the diffusion problem, including properly defined boundary conditions. A formula for the diffusion coefficient different from that based on averaging the transport mean-free-path is derived

  8. Bridging asymptotic independence and dependence in spatial exbtremes using Gaussian scale mixtures

    KAUST Repository

    Huser, Raphaël

    2017-06-23

    Gaussian scale mixtures are constructed as Gaussian processes with a random variance. They have non-Gaussian marginals and can exhibit asymptotic dependence unlike Gaussian processes, which are asymptotically independent except in the case of perfect dependence. In this paper, we study the extremal dependence properties of Gaussian scale mixtures and we unify and extend general results on their joint tail decay rates in both asymptotic dependence and independence cases. Motivated by the analysis of spatial extremes, we propose flexible yet parsimonious parametric copula models that smoothly interpolate from asymptotic dependence to independence and include the Gaussian dependence as a special case. We show how these new models can be fitted to high threshold exceedances using a censored likelihood approach, and we demonstrate that they provide valuable information about tail characteristics. In particular, by borrowing strength across locations, our parametric model-based approach can also be used to provide evidence for or against either asymptotic dependence class, hence complementing information given at an exploratory stage by the widely used nonparametric or parametric estimates of the χ and χ̄ coefficients. We demonstrate the capacity of our methodology by adequately capturing the extremal properties of wind speed data collected in the Pacific Northwest, US.

  9. Bridging asymptotic independence and dependence in spatial exbtremes using Gaussian scale mixtures

    KAUST Repository

    Huser, Raphaë l; Opitz, Thomas; Thibaud, Emeric

    2017-01-01

    Gaussian scale mixtures are constructed as Gaussian processes with a random variance. They have non-Gaussian marginals and can exhibit asymptotic dependence unlike Gaussian processes, which are asymptotically independent except in the case of perfect dependence. In this paper, we study the extremal dependence properties of Gaussian scale mixtures and we unify and extend general results on their joint tail decay rates in both asymptotic dependence and independence cases. Motivated by the analysis of spatial extremes, we propose flexible yet parsimonious parametric copula models that smoothly interpolate from asymptotic dependence to independence and include the Gaussian dependence as a special case. We show how these new models can be fitted to high threshold exceedances using a censored likelihood approach, and we demonstrate that they provide valuable information about tail characteristics. In particular, by borrowing strength across locations, our parametric model-based approach can also be used to provide evidence for or against either asymptotic dependence class, hence complementing information given at an exploratory stage by the widely used nonparametric or parametric estimates of the χ and χ̄ coefficients. We demonstrate the capacity of our methodology by adequately capturing the extremal properties of wind speed data collected in the Pacific Northwest, US.

  10. EMC effect: asymptotic freedom with nuclear targets

    International Nuclear Information System (INIS)

    West, G.B.

    1984-01-01

    General features of the EMC effect are discussed within the framework of quantum chromodynamics as expressed via the operator product expansion and asymptotic freedom. These techniques are reviewed with emphasis on the target dependence. 22 references

  11. Asymptotic Likelihood Distribution for Correlated & Constrained Systems

    CERN Document Server

    Agarwal, Ujjwal

    2016-01-01

    It describes my work as summer student at CERN. The report discusses the asymptotic distribution of the likelihood ratio for total no. of parameters being h and 2 out of these being are constrained and correlated.

  12. Structure of the gravitational field at spatial infinity. II. Asymptotically Minkowskian space--times

    International Nuclear Information System (INIS)

    Persides, S.

    1980-01-01

    A new formulation is established for the study of the asymptotic structure at spatial infinity of asymptotically Minkowskian space--times. First, the concept of an asymptotically simple space--time at spatial infinity is defined. This is a (physical) space--time (M,g) which can be imbedded in an unphysical space--time (M,g) with a boundary S, a C/sup infinity/ metric g and a C/sup infinity/ scalar field Ω such that Ω=0 on S, Ω>0 on M-S, and g/sup munu/ + g/sup mulambda/ g/sup nurho/ Ω/sub vertical-barlambda/ Ω/sub vertical-barrho/=Ω -2 g/sup murho/ +Ω -4 g/sup mulambda/ g/sup nurho/ Ω/sub ;/lambda Ω/sub ;/rho on M. Then an almost asymptotically flat space--time (AAFS) is defined as an asymptotically simple space--time for which S is isometric to the unit timelike hyperboloid and g/sup munu/ Ω/sub vertical-barmu/ Ω/sub vertical-barnu/ =Ω -4 g/sup munu/ Ω/sub ;/μΩ/sub ;/ν=-1 on S. Equivalent definitions are given in terms of the existence of coordinate systems in which g/sub munu/ or g/sub munu/ have simple explicitly given forms. The group of asymptotic symmetries of (M,g) is studied and is found to be isomorphic to the Lorentz group. The asymptotic behavior of an AAFS is studied. It is proven that the conformal metric g/sub munu/=Ω 2 g/sub munu/ gives C/sup lambdamurhonu/=0, Ω -1 C/sup lambdamurhonu/ Ω/sub ;/μ =0, Ω -2 C/sup lambdamurhonu/ Ω/sub ;/μ Ω/sub ;/ν=0 on S

  13. Asymptotic behaviour and stability of solutions of a singularly perturbed elliptic problem with a triple root of the degenerate equation

    Science.gov (United States)

    Butuzov, V. F.

    2017-06-01

    We construct and justify asymptotic expansions of solutions of a singularly perturbed elliptic problem with Dirichlet boundary conditions in the case when the corresponding degenerate equation has a triple root. In contrast to the case of a simple root, the expansion is with respect to fractional (non-integral) powers of the small parameter, the boundary-layer variables have another scaling, and the boundary layer has three zones. This gives rise to essential modifications in the algorithm for constructing the boundary functions. Solutions of the elliptic problem are stationary solutions of the corresponding parabolic problem. We prove that such a stationary solution is asymptotically stable and find its global domain of attraction.

  14. Assessing model fit in latent class analysis when asymptotics do not hold

    NARCIS (Netherlands)

    van Kollenburg, Geert H.; Mulder, Joris; Vermunt, Jeroen K.

    2015-01-01

    The application of latent class (LC) analysis involves evaluating the LC model using goodness-of-fit statistics. To assess the misfit of a specified model, say with the Pearson chi-squared statistic, a p-value can be obtained using an asymptotic reference distribution. However, asymptotic p-values

  15. Spectral asymptotic in the large coupling limit

    CERN Document Server

    Bruneau, V

    2002-01-01

    In this paper, we study a singular perturbation of an eigenvalues problem related to supra-conductor wave guides. Using boundary layer tools we perform a complete asymptotic expansion of the eigenvalues as the conductivity tends to $+\\infty$.

  16. TEACHING NEUROMUSCULAR RELAXATION.

    Science.gov (United States)

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  17. Optimal Homotopy Asymptotic Method for Solving System of Fredholm Integral Equations

    Directory of Open Access Journals (Sweden)

    Bahman Ghazanfari

    2013-08-01

    Full Text Available In this paper, optimal homotopy asymptotic method (OHAM is applied to solve system of Fredholm integral equations. The effectiveness of optimal homotopy asymptotic method is presented. This method provides easy tools to control the convergence region of approximating solution series wherever necessary. The results of OHAM are compared with homotopy perturbation method (HPM and Taylor series expansion method (TSEM.

  18. Globally asymptotically stable analysis in a discrete time eco-epidemiological system

    International Nuclear Information System (INIS)

    Hu, Zengyun; Teng, Zhidong; Zhang, Tailei; Zhou, Qiming; Chen, Xi

    2017-01-01

    Highlights: • Dynamical behaviors of a discrete time eco-epidemiological system are discussed. • Global asymptotical stability of this system is obtained by an iteration scheme which can be expended to general dimensional discrete system. • More complex dynamical behaviors are obtained by numerical simulations. - Abstract: In this study, the dynamical behaviors of a discrete time eco-epidemiological system are discussed. The local stability, bifurcation and chaos are obtained. Moreover, the global asymptotical stability of this system is explored by an iteration scheme. The numerical simulations illustrate the theoretical results and exhibit the complex dynamical behaviors such as flip bifurcation, Hopf bifurcation and chaotic dynamical behaviors. Our main results provide an efficient method to analyze the global asymptotical stability for general three dimensional discrete systems.

  19. More is less: Learning but not relaxing buffers deviance under job stressors.

    Science.gov (United States)

    Zhang, Chen; Mayer, David M; Hwang, Eunbit

    2018-02-01

    Workplace deviance harms the well-being of an organization and its members. Unfortunately, theory and prior research suggest that deviance is associated with job stressors, which are endemic to work organizations and often cannot be easily eliminated. To address this conundrum, we explore actions individuals can take at work that serve as buffering conditions for the positive relationship between job stressors and deviant behavior. Drawing upon conservation of resources theory, we examine a resource-building activity (i.e., learning something new at work) and a demand-shielding activity (i.e., taking time for relaxation at work) as potential boundary conditions. In 2 studies with employee samples using complementary designs, we find support for the buffering role of learning but not for relaxation. When employees learn new things at work, the relationship between hindrance stressors and deviance is weaker; as is the indirect relationship mediated by negative emotions. Taking time for relaxation at work did not show a moderating role in either study. Therefore, although relaxation is a response that individuals might be inclined to turn to for counteracting work stress, our findings suggest that, when it comes to addressing negative emotions and deviance in stressful work environments, building positive resources by learning something new at work could be more useful. In that way, doing more (i.e., learning, and not relaxing) is associated with less (deviance) in the face of job stressors. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  20. The Effects of Progressive Relaxation and Music on Attention, Relaxation, and Stress Responses: An Investigation of the Cognitive-Behavioral Model of Relaxation

    National Research Council Canada - National Science Library

    Scheufele, Peter

    1999-01-01

    ...) suggested that stress management techniques have specific effects A compromise position suggests that the specific effects of relaxation techniques are superimposed upon a general relaxation response...

  1. Inverse curvature flows in asymptotically Robertson Walker spaces

    Science.gov (United States)

    Kröner, Heiko

    2018-04-01

    In this paper we consider inverse curvature flows in a Lorentzian manifold N which is the topological product of the real numbers with a closed Riemannian manifold and equipped with a Lorentzian metric having a future singularity so that N is asymptotically Robertson Walker. The flow speeds are future directed and given by 1 / F where F is a homogeneous degree one curvature function of class (K*) of the principal curvatures, i.e. the n-th root of the Gauss curvature. We prove longtime existence of these flows and that the flow hypersurfaces converge to smooth functions when they are rescaled with a proper factor which results from the asymptotics of the metric.

  2. Finite element analysis of the biaxial cyclic tensile loading of the elastoplastic plate with the central hole: asymptotic regimes

    Science.gov (United States)

    Turkova, Vera; Stepanova, Larisa

    2018-03-01

    For elastistoplastic structure elements under cyclic loading three types of asymptotic behavior are well known: shakedown, cyclic plasticity or ratcheting. In structure elements operating in real conditions ratcheting must always be excluded since it caused the incremental fracture of structure by means of the accumulation of plastic strains. In the present study results of finite-element (FEM) calculations of the asymptotical behavior of an elastoplastic plate with the central circular and elliptic holes under the biaxial cyclic loading for three different materials are presented. Incremental cyclic loading of the sample with stress concentrator (the central hole) is performed in the multifunctional finite-element package SIMULIA Abaqus. The ranges of loads found for shakedown, cyclic plasticity and ratcheting are presented. The results obtained are generalized and analyzed. Convenient normalization is suggested. The chosen normalization allows us to present all computed results, corresponding to separate materials, within one common curve with minimum scattering of the points. Convenience of the generalized diagram consists in a possibility to find an asymptotical behavior of an inelastic structure for materials for which computer calculations were not made.

  3. Asymptotic theory of two-dimensional trailing-edge flows

    Science.gov (United States)

    Melnik, R. E.; Chow, R.

    1975-01-01

    Problems of laminar and turbulent viscous interaction near trailing edges of streamlined bodies are considered. Asymptotic expansions of the Navier-Stokes equations in the limit of large Reynolds numbers are used to describe the local solution near the trailing edge of cusped or nearly cusped airfoils at small angles of attack in compressible flow. A complicated inverse iterative procedure, involving finite-difference solutions of the triple-deck equations coupled with asymptotic solutions of the boundary values, is used to accurately solve the viscous interaction problem. Results are given for the correction to the boundary-layer solution for drag of a finite flat plate at zero angle of attack and for the viscous correction to the lift of an airfoil at incidence. A rational asymptotic theory is developed for treating turbulent interactions near trailing edges and is shown to lead to a multilayer structure of turbulent boundary layers. The flow over most of the boundary layer is described by a Lighthill model of inviscid rotational flow. The main features of the model are discussed and a sample solution for the skin friction is obtained and compared with the data of Schubauer and Klebanoff for a turbulent flow in a moderately large adverse pressure gradient.

  4. Physically asymptotic Hartree-Fock stationary-phase approximant to the many-body S-matrix

    International Nuclear Information System (INIS)

    Griffin, J.J.; Dworzecka, M.

    1982-01-01

    The Asymptotic Hartree-Fock Approximant replaces the physically non-asymptotic (and dynamically nontrivial) external translation of the FISP result with the asymptotic and dynamically trivial translational evolution of Dirac-TDHF by adding an explicit restriction upon the acceptable channel states. It is therefore preferable under the principle of commensurability, which judges the expected output of physical descriptions in terms of the physical assumptions they incorporate. Further insight into the relationship between the TDSHF and FISP methods will reward careful comparison of the respective expressions, in specific cases

  5. Ultraviolet asymptotic behavior of the photon propagator in dimensionally regularized quantum electrodynamics

    International Nuclear Information System (INIS)

    Krasnikov, N.V.

    1991-01-01

    Study of the ultraviolet behavior of asymptotically nonfree theories is one of the most important problems of quantum field theory. Unfortunately, not too much is known about the ultraviolet properties in asymptotically nonfree theories; the main obstacle is the growth of the effective coupling constant in the ultraviolet region, which renders perturbation theory inapplicable. It is shown that in quantum electrodynamics in n = 4 + 2 var-epsilon space-time (var-epsilon > 0) the photon propagator has the ultraviolet asymptotic behavior D(k 2 ) ∼ (k 2 ) -1-var-epsilon . In the case var-epsilon R ≤ -3π var-epsilon + O(var-epsilon 2 )

  6. Relaxation creep model of impending earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Morgounov, V. A. [Russian Academy of Sciences, Institute of Physics of the Earth, Moscow (Russian Federation)

    2001-04-01

    The alternative view of the current status and perspective of seismic prediction studies is discussed. In the problem of the ascertainment of the uncertainty relation Cognoscibility-Unpredictability of Earthquakes, priorities of works on short-term earthquake prediction are defined due to the advantage that the final stage of nucleation of earthquake is characterized by a substantial activation of the process while its strain rate increases by the orders of magnitude and considerably increased signal-to-noise ratio. Based on the creep phenomenon under stress relaxation conditions, a model is proposed to explain different images of precursors of impending tectonic earthquakes. The onset of tertiary creep appears to correspond to the onset of instability and inevitably fails unless it unloaded. At this stage, the process acquires the self-regulating character to the greatest extent the property of irreversibility, one of the important components of prediction reliability. Data in situ suggest a principal possibility to diagnose the process of preparation by ground measurements of acoustic and electromagnetic emission in the rocks under constant strain in the condition of self-relaxed stress until the moment of fracture are discussed in context. It was obtained that electromagnetic emission precedes but does not accompany the phase of macrocrak development.

  7. Yoga Nidra relaxation increases heart rate variability and is unaffected by a prior bout of Hatha yoga.

    Science.gov (United States)

    Markil, Nina; Whitehurst, Michael; Jacobs, Patrick L; Zoeller, Robert F

    2012-10-01

    The measurement of heart rate variability (HRV) is often applied as an index of autonomic nervous system (ANS) balance and, therefore, myocardial stability. Previous studies have suggested that relaxation or mind-body exercise can influence ANS balance positively as measured by HRV but may act via different mechanisms. No studies, to the authors' knowledge, have examined the acute response in HRV to interventions combining relaxation and mind-body exercise. The objective of this study was to compare the acute HRV responses to Yoga Nidra relaxation alone versus Yoga Nidra relaxation preceded by Hatha yoga. This was a randomized counter-balanced trial. The trial was conducted in a university exercise physiology laboratory. Subjects included 20 women and men (29.15±6.98 years of age, with a range of 18-47 years). Participants completed a yoga plus relaxation (YR) session and a relaxation only (R) session. The YR condition produced significant changes from baseline in heart rate (HR; beats per minute [bpm], pheart rate (bpm, p<0.001) as well as indices of HRV: R-R (ms, p<0.001), HF (ms(2), p=0.004), LF (%, p=0.005), HF (%, p=0.008) and LF:HF ratio (%, p=0.008). There were no significant differences between conditions at baseline nor for the changes from baseline for any of the variables. These changes demonstrate a favorable shift in autonomic balance to the parasympathetic branch of the ANS for both conditions, and that Yoga Nidra relaxation produces favorable changes in measures of HRV whether alone or preceded by a bout of Hatha yoga.

  8. High frequency asymptotic methods

    International Nuclear Information System (INIS)

    Bouche, D.; Dessarce, R.; Gay, J.; Vermersch, S.

    1991-01-01

    The asymptotic methods allow us to compute the interaction of high frequency electromagnetic waves with structures. After an outline of their foundations with emphasis on the geometrical theory of diffraction, it is shown how to use these methods to evaluate the radar cross section (RCS) of complex tri-dimensional objects of great size compared to the wave-length. The different stages in simulating phenomena which contribute to the RCS are reviewed: physical theory of diffraction, multiple interactions computed by shooting rays, research for creeping rays. (author). 7 refs., 6 figs., 3 insets

  9. Existence and asymptotic behavior of solutions for nonlinear Schrödinger-Poisson systems with steep potential well.

    Science.gov (United States)

    Du, Miao; Tian, Lixin; Wang, Jun; Zhang, Fubao

    2016-03-01

    In this paper, we are concerned with a class of Schrödinger-Poisson systems with the asymptotically linear or asymptotically 3-linear nonlinearity. Under some suitable assumptions on V , K , a , and f , we prove the existence, nonexistence, and asymptotic behavior of solutions via variational methods. In particular, the potential V is allowed to be sign-changing for the asymptotically linear case.

  10. Sharp asymptotic estimates for vorticity solutions of the 2D Navier-Stokes equation

    Directory of Open Access Journals (Sweden)

    Yuncheng You

    2008-12-01

    Full Text Available The asymptotic dynamics of high-order temporal-spatial derivatives of the two-dimensional vorticity and velocity of an incompressible, viscous fluid flow in $mathbb{R}^2$ are studied, which is equivalent to the 2D Navier-Stokes equation. It is known that for any integrable initial vorticity, the 2D vorticity solution converges to the Oseen vortex. In this paper, sharp exterior decay estimates of the temporal-spatial derivatives of the vorticity solution are established. These estimates are then used and combined with similarity and $L^p$ compactness to show the asymptotical attraction rates of temporal-spatial derivatives of generic 2D vorticity and velocity solutions by the Oseen vortices and velocity solutions respectively. The asymptotic estimates and the asymptotic attraction rates of all the derivatives obtained in this paper are independent of low or high Reynolds numbers.

  11. Asymptotic Poisson distribution for the number of system failures of a monotone system

    International Nuclear Information System (INIS)

    Aven, Terje; Haukis, Harald

    1997-01-01

    It is well known that for highly available monotone systems, the time to the first system failure is approximately exponentially distributed. Various normalising factors can be used as the parameter of the exponential distribution to ensure the asymptotic exponentiality. More generally, it can be shown that the number of system failures is asymptotic Poisson distributed. In this paper we study the performance of some of the normalising factors by using Monte Carlo simulation. The results show that the exponential/Poisson distribution gives in general very good approximations for highly available components. The asymptotic failure rate of the system gives best results when the process is in steady state, whereas other normalising factors seem preferable when the process is not in steady state. From a computational point of view the asymptotic system failure rate is most attractive

  12. Effects of music listening and relaxation instructions on arousal changes and the working memory task in older adults.

    Science.gov (United States)

    Hirokawa, Eri

    2004-01-01

    The purpose of this study was to examine the effects of subject-preferred music and relaxation instructions on older adults' arousal and working memory. Fifteen female older adults participated in 10 minutes of all 3 experimental conditions: (a) subject-preferred music, (b) relaxation instructions, and (c) silence control. Four subcategories of arousal level, energy, tiredness, tension, and calmness, were measured before and after experimental treatment using the Activation-Deactivation Adjective Check List by Thayer (1978). After each experimental condition, subjects had a working memory test by Daneman and Carpenter (1980). Results of the 2 x 3 repeated measures analysis of variances indicated that music increased subjects' energy levels, but relaxation and silence significantly decreased energy levels. Relaxation and silence increased their tiredness and calmness levels. All experimental conditions decreased subjects' tension levels. The scores in the working memory test were not significantly different among experimental conditions. Results did not indicate clear relationships between four subcategories of arousal levels and working memory scores. Results indicated that subject-preferred music has potentials to increase older adults' energetic arousal and reduce tension.

  13. An electromyographic study of muscle relaxants in man.

    Science.gov (United States)

    Suzuki, H; Kanayama, T; Nakagawa, H; Yazaki, S; Shiratsuchi, T

    1975-05-01

    Supramaximal paired stimuli were applied to the ulnar nerve, and the amplitude of the muscle action potential evoked in the abductor digiti minimi by the second member of the stimulus pair (test response) was compared with that evoked by the first component (conditioning response). The interval between the two components of the stimulus pair (the pair interval) was increased stepwise from 7 to 100 msec and a curve (recovery curve) was obtained by relating the changes in pair interval to the difference in amplitude of the test and conditioning responses. Alterations of the recovery curve (RC) during partial paralysis by muscle relaxants were investigated in healthy adult patients under the lightest plane of general anaesthesia. The control curve obtained in 32 subjects before the administration of a muscle relaxant drug was characterized by slight depressions at very short intervals of paired stimuli, followed by a slight potentiation at 20-100 msec. With non-depolarizing relaxants, RC altered to the characteristic pattern of potentiation at very short intervals of stimuli, followed by a notable depression at longer intervals. In depolarizing blocks with small doses of suxamethonium, the depression of RC at short intervals in the control was enhanced and the pattern of RC was different from that of non-depolarizing agents. When desensitization blocks were instigated by the i.v. administration of suxamethonium, the RC patterns were similar to those of competitive agents.

  14. Microstructural stress relaxation mechanics in functionally different tendons.

    Science.gov (United States)

    Screen, H R C; Toorani, S; Shelton, J C

    2013-01-01

    Tendons experience widely varying loading conditions in vivo. They may be categorised by their function as either positional tendons, which are used for intricate movements and experience lower stress, or as energy storage tendons which act as highly stressed springs during locomotion. Structural and compositional differences between tendons are thought to enable an optimisation of their properties to suit their functional environment. However, little is known about structure-function relationships in tendon. This study adopts porcine flexor and extensor tendon fascicles as examples of high stress and low stress tendons, comparing their mechanical behaviour at the micro-level in order to understand their stress relaxation response. Stress-relaxation was shown to occur predominantly through sliding between collagen fibres. However, in the more highly stressed flexor tendon fascicles, more fibre reorganisation was evident when the tissue was exposed to low strains. By contrast, the low load extensor tendon fascicles appears to have less capacity for fibre reorganisation or shearing than the energy storage tendon, relying more heavily on fibril level relaxation. The extensor fascicles were also unable to sustain loads without rapid and complete stress relaxation. These findings highlight the need to optimise tendon repair solutions for specific tendons, and match tendon properties when using grafts in tendon repairs. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  15. Magnetic relaxation in anisotropic magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1971-01-01

    The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse...... or longitudinal relaxation function depending on the sign of the axial anisotropy....

  16. Asymptotic analysis of the role of spatial sampling for covariance parameter estimation of Gaussian processes

    International Nuclear Information System (INIS)

    Bachoc, Francois

    2014-01-01

    Covariance parameter estimation of Gaussian processes is analyzed in an asymptotic framework. The spatial sampling is a randomly perturbed regular grid and its deviation from the perfect regular grid is controlled by a single scalar regularity parameter. Consistency and asymptotic normality are proved for the Maximum Likelihood and Cross Validation estimators of the covariance parameters. The asymptotic covariance matrices of the covariance parameter estimators are deterministic functions of the regularity parameter. By means of an exhaustive study of the asymptotic covariance matrices, it is shown that the estimation is improved when the regular grid is strongly perturbed. Hence, an asymptotic confirmation is given to the commonly admitted fact that using groups of observation points with small spacing is beneficial to covariance function estimation. Finally, the prediction error, using a consistent estimator of the covariance parameters, is analyzed in detail. (authors)

  17. Asymptotic expansions close to the singularity in Gowdy spacetimes[04.20.Dw Singularities and cosmic censorship;

    Energy Technology Data Exchange (ETDEWEB)

    Ringstroem, Hans [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, D-14476 Golm (Germany)

    2004-02-07

    We consider Gowdy spacetimes under the assumption that the spatial hypersurfaces are diffeomorphic to the torus. The relevant equations are then wave map equations with the hyperbolic space as a target. In a paper by Grubisic and Moncrief, a formal expansion of solutions in the direction towards the singularity was proposed. Later, Kichenassamy and Rendall constructed a family of real analytic solutions with the maximum number of free functions and the desired asymptotics at the singularity. The condition of real analyticity was subsequently removed by Rendall. In a previous paper, we proved that one can put a condition on initial data that leads to asymptotic expansions. However, control of up to and including three derivatives in L{sup 2} was necessary, and the condition was rather technical. The main point of the present paper is to demonstrate the existence of certain monotone quantities and to illustrate how these can be used to weaken the assumptions to one derivative in the sup norm. Furthermore, we demonstrate that the false spikes do not appear in the disc model. Finally, we show that knowledge concerning the behaviour of the solution (as time tends to the singularity) for one fixed spatial point in some situations can be used to conclude that there are smooth expansions in the neighbourhood of that spatial point.

  18. Relaxation to equilibrium following photoacid dissociation in mineral acids and buffer solutions

    International Nuclear Information System (INIS)

    Pines, D; Nibbering, E T J; Pines, E

    2007-01-01

    The relaxation to the dissociation equilibrium of a weak acid undergoing a transient pK a change in the presence of a strong mineral acid has been the subject of considerable interest both experimentally and theoretically. Here we compare this process with the analogue event taking place in a buffer solution of a weak carboxylic acid. The comparison has been performed in identical pH and ionic strength conditions and at a sufficiently short timescale where the buffer can only affect the weak acid relaxation by proton scavenging. Although the two relaxation processes have been found to differ in their temporal behaviour, they have both resulted in identical equilibrium amplitudes of the photoacid. This observation reassures the well-known chemical wisdom that pK a values measured in buffer solutions do not depend on the specific chemical reactivity of the buffer. We analyse the essentially many-body relaxation problem in terms of a re-normalized geminate recombination reaction which persists over longer times than the exponential relaxation to equilibrium of homogenously distributed populations of the reactants

  19. Effect of thermal exposure on the residual stress relaxation in a hardened cylindrical sample under creep conditions

    Science.gov (United States)

    Radchenko, V. P.; Saushkin, M. N.; Tsvetkov, V. V.

    2016-05-01

    This paper describes the effect of thermal exposure (high-temperature exposure) ( T = 675°C) on the residual creep stress relaxation in a surface hardened solid cylindrical sample made of ZhS6UVI alloy. The analysis is carried out with the use of experimental data for residual stresses after micro-shot peening and exposures to temperatures equal to T = 675°C during 50, 150, and 300 h. The paper presents the technique for solving the boundary-value creep problem for the hardened cylindrical sample with the initial stress-strain state under the condition of thermal exposure. The uniaxial experimental creep curves obtained under constant stresses of 500, 530, 570, and 600 MPa are used to construct the models describing the primary and secondary stages of creep. The calculated and experimental data for the longitudinal (axial) tensor components of residual stresses are compared, and their satisfactory agreement is determined.

  20. Asymptotic behavior of the warm inflation scenario with viscous pressure

    International Nuclear Information System (INIS)

    Mimoso, Jose P.; Nunes, Ana; Pavon, Diego

    2006-01-01

    We analyze the dynamics of models of warm inflation with general dissipative effects. We consider phenomenological terms both for the inflaton decay rate and for viscous effects within matter. We provide a classification of the asymptotic behavior of these models and show that the existence of a late-time scaling regime depends not only on an asymptotic behavior of the scalar field potential, but also on an appropriate asymptotic behavior of the inflaton decay rate. There are scaling solutions whenever the latter evolves to become proportional to the Hubble rate of expansion regardless of the steepness of the scalar field exponential potential. We show from thermodynamic arguments that the scaling regime is associated with a power-law dependence of the matter-radiation temperature on the scale factor, which allows a mild variation of the temperature of the matter/radiation fluid. We also show that the late-time contribution of the dissipative terms alleviates the depletion of matter, and increases the duration of inflation

  1. THE MATHEMATIC MODEL OF POTENTIAL RELAXATION IN COULOSTATIC CONDITIONS FOR LIMITING DIFFUSION CURRENT CASE

    Directory of Open Access Journals (Sweden)

    O. H. Kapitonov

    2010-05-01

    Full Text Available A mathematical model of coulostatic relaxation of the potential for solid metallic electrode was presented. The solution in the case of limiting diffusion current was obtained. On the basis of this model the technique of concentration measurements for heavy metal ions in diluted solutions was suggested. The model adequacy was proved by experimental data.

  2. The effects of the contract-relax-antagonist-contract form of proprioceptive neuromuscular facilitation stretching on postural stability.

    Science.gov (United States)

    Ryan, Edwin E; Rossi, Mark D; Lopez, Richard

    2010-07-01

    To investigate the effects of the contract-relax-antagonist-contract (CRAC) form of proprioceptive neuromuscular facilitation (PNF) stretching, with and without a warm-up, on postural stability. Thirty volunteers (15 men and 15 women, age: 25.17 +/- 5.4 years, height: 173.76 +/- 8.2 cm, and weight: 72.03 +/- 14.87 kg) were randomly assigned to 1 of 3 conditions: warm-up and stretch (WS), stretching only (SO), and a control condition (CON). Contract-relax-antagonist-contract PNF of the hamstrings, plantar flexors, and hip flexors was performed during WS and SO. A 6-minute treadmill warm-up was applied before CRAC in the WS condition. Measures of anterior/posterior and medial/lateral (M/L) postural stability were taken before and after treatment conditions. A 2 x 3 analysis of variance was used to assess for differences between conditions. Significance was set at p Contract-relax-antagonist-contract form of stretching is a useful protocol for improving M/L stability.

  3. Asymptotic absolute continuity for perturbed time-dependent ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    We study the notion of asymptotic velocity for a class of perturbed time- ... for Mathematical Physics and Stochastics, funded by a grant from the Danish National Research Foun- .... Using (2.4) we can readily continue α(t) to the whole half-axis.

  4. Asymptotic integration of some nonlinear differential equations with fractional time derivative

    International Nuclear Information System (INIS)

    Baleanu, Dumitru; Agarwal, Ravi P; Mustafa, Octavian G; Cosulschi, Mirel

    2011-01-01

    We establish that, under some simple integral conditions regarding the nonlinearity, the (1 + α)-order fractional differential equation 0 D α t (x') + f(t, x) = 0, t > 0, has a solution x element of C([0,+∞),R) intersection C 1 ((0,+∞),R), with lim t→0 [t 1-α x'(t)] element of R, which can be expanded asymptotically as a + bt α + O(t α-1 ) when t → +∞ for given real numbers a, b. Our arguments are based on fixed point theory. Here, 0 D α t designates the Riemann-Liouville derivative of order α in (0, 1).

  5. Fast-slow asymptotics for a Markov chain model of fast sodium current

    Science.gov (United States)

    Starý, Tomáš; Biktashev, Vadim N.

    2017-09-01

    We explore the feasibility of using fast-slow asymptotics to eliminate the computational stiffness of discrete-state, continuous-time deterministic Markov chain models of ionic channels underlying cardiac excitability. We focus on a Markov chain model of fast sodium current, and investigate its asymptotic behaviour with respect to small parameters identified in different ways.

  6. Asymptotics of pion electromagnetics form factor in scale invariant quark model

    International Nuclear Information System (INIS)

    Efremov, A.V.; Radyushkin, A.V.

    1976-01-01

    A consistent relativistic approach is proposed to the investigation of asymptotic behaviour of form factor of a system, composed of two spinor particles, interacting with the vector of (pseudo) scalar neutral field. It is shown that the assumption of finite and small asymptotical value of quark-gluon interaction invariant charge at small distances (g 9 2 9 2 ln(-Q 2 ) 2 values (Q 2 is squared momentum)

  7. Mass loss by stars at the stage of the asymptotic giant branch

    International Nuclear Information System (INIS)

    Frantsman, Y.L.

    1986-01-01

    For a given initial stellar mass function, star formation function, and initial chemical composition, distributions have been constructed for stars of the asymptotic giant branch by luminosity, and for white dwarfs by mass, by calculating the approximate evolution of a large number of stars. Variants are calculated with different assumptions about the mass loss in the asymptotic branch. Theory can be reconciled with observation only if it is assumed that at this stage there is also a still large mass loss in addition to the stellar wind and the ejection of a planetary nebula shell. This provides the explanation for the absence in the Magellanic clouds of carbon stars with M /sub bol/ 1.0M /sub ./. The degenerate carbon-oxygen nuclei of stars evolving along the asymptotic giant branch cannot attain the Chandrasekhar limit on account of the great mass loss by the stars. The luminosity of stars of the asymptotic giant branch in the globular clusters of the Magellanic Clouds is a good indicator of the age of the clusters

  8. Strong Convergence Theorems for a Countable Family of Total Quasi-ϕ-Asymptotically Nonexpansive Nonself Mappings

    Directory of Open Access Journals (Sweden)

    Liang-cai Zhao

    2012-01-01

    Full Text Available The purpose of this paper is to introduce a class of total quasi-ϕ-asymptotically nonexpansive-nonself mappings and to study the strong convergence under a limit condition only in the framework of Banach spaces. As an application, we utilize our results to study the approximation problem of solution to a system of equilibrium problems. The results presented in the paper extend and improve the corresponding results announced by some authors recently.

  9. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  10. Asymptotic behavior of a rotational population distribution in a molecular quantum-kicked rotor with ideal quantum resonance

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Leo, E-mail: leo-matsuoka@hiroshima-u.ac.jp [Graduate School of Engineering, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8527 (Japan); Segawa, Etsuo [Graduate School of Information Sciences, Tohoku University, Aoba, Sendai 980-8579 (Japan); Yuki, Kenta [Graduate School of Engineering, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8527 (Japan); Konno, Norio [Department of Applied Mathematics, Faculty of Engineering, Yokohama National University, Hodogaya, Yokohama 240-8501 (Japan); Obata, Nobuaki [Graduate School of Information Sciences, Tohoku University, Aoba, Sendai 980-8579 (Japan)

    2017-06-09

    We performed a mathematical analysis of the time-dependent dynamics of a quantum-kicked rotor implemented in a diatomic molecule under the condition of ideal quantum resonance. We examined a model system featuring a diatomic molecule in a periodic train of terahertz pulses, regarding the molecule as a rigid rotor with the state-dependent transition moment and including the effect of the magnetic quantum number M. We derived the explicit expression for the asymptotic distribution of a rotational population by making the transition matrix correspondent with a sequence of ultraspherical polynomials. The mathematical results obtained were validated by numerical simulations. - Highlights: • The behavior of the molecular quantum-kicked rotor was mathematically investigated. • The matrix elements were made correspondent with the ultraspherical polynomials. • The explicit formula for asymptotic distribution was obtained. • Complete agreement with the numerical simulation was verified.

  11. Asymptotic sequences over ideals and projectively equivalent ideals with respect to modules

    International Nuclear Information System (INIS)

    Naghipour, R.; Sedghi, M.

    2007-09-01

    Let R be a commutative Noetherian ring, and let N be a non-zero finitely generated R-module. The purpose of this paper is to show that if I and J are projectively equivalent ideals w.r.t. N, then a sequence x := x 1 , . . . , x n of elements of R is an asymptotic sequence over I w.r.t. N if and only if it is an asymptotic sequence over J w.r.t. N. Also, it is shown that if R is local, then the lengths of all maximal asymptotic sequences over an ideal I w.r.t. N are the same. As a consequence we derive a generalization of Rees' theorem. (author)

  12. Asymptotically AdS spacetimes with a timelike Kasner singularity

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jie [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

    2016-07-21

    Exact solutions to Einstein’s equations for holographic models are presented and studied. The IR geometry has a timelike cousin of the Kasner singularity, which is the less generic case of the BKL (Belinski-Khalatnikov-Lifshitz) singularity, and the UV is asymptotically AdS. This solution describes a holographic RG flow between them. The solution’s appearance is an interpolation between the planar AdS black hole and the AdS soliton. The causality constraint is always satisfied. The entanglement entropy and Wilson loops are discussed. The boundary condition for the current-current correlation function and the Laplacian in the IR is examined. There is no infalling wave in the IR, but instead, there is a normalizable solution in the IR. In a special case, a hyperscaling-violating geometry is obtained after a dimensional reduction.

  13. Radiative observables for linearized gravity on asymptotically flat spacetimes and their boundary induced states

    International Nuclear Information System (INIS)

    Benini, Marco; Dappiaggi, Claudio; Murro, Simone

    2014-01-01

    We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes, and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ℑ + . The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ℑ + . This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos [“Asymptotic simplicity is stable,” J. Math. Phys. 19, 714 (1978)], is imposed. We review its definition critically, showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed

  14. Asymptotic behavior of quark masses induced by instantons

    International Nuclear Information System (INIS)

    Carneiro, C.E.I.; Frenkel, J.

    1984-02-01

    A simple argument which shows that the dynamical mass induced by interactions of massless quarks with pseudo-particle configurations, behaves like p -6 for asymptotically large quark momenta is presented. (Author) [pt

  15. Non-linear and signal energy optimal asymptotic filter design

    Directory of Open Access Journals (Sweden)

    Josef Hrusak

    2003-10-01

    Full Text Available The paper studies some connections between the main results of the well known Wiener-Kalman-Bucy stochastic approach to filtering problems based mainly on the linear stochastic estimation theory and emphasizing the optimality aspects of the achieved results and the classical deterministic frequency domain linear filters such as Chebyshev, Butterworth, Bessel, etc. A new non-stochastic but not necessarily deterministic (possibly non-linear alternative approach called asymptotic filtering based mainly on the concepts of signal power, signal energy and a system equivalence relation plays an important role in the presentation. Filtering error invariance and convergence aspects are emphasized in the approach. It is shown that introducing the signal power as the quantitative measure of energy dissipation makes it possible to achieve reasonable results from the optimality point of view as well. The property of structural energy dissipativeness is one of the most important and fundamental features of resulting filters. Therefore, it is natural to call them asymptotic filters. The notion of the asymptotic filter is carried in the paper as a proper tool in order to unify stochastic and non-stochastic, linear and nonlinear approaches to signal filtering.

  16. Asymptotics for the minimum covariance determinant estimator

    NARCIS (Netherlands)

    Butler, R.W.; Davies, P.L.; Jhun, M.

    1993-01-01

    Consistency is shown for the minimum covariance determinant (MCD) estimators of multivariate location and scale and asymptotic normality is shown for the former. The proofs are made possible by showing a separating ellipsoid property for the MCD subset of observations. An analogous property is shown

  17. Group hypnotherapy versus group relaxation for smoking cessation: an RCT study protocol

    Directory of Open Access Journals (Sweden)

    Dickson-Spillmann Maria

    2012-04-01

    Full Text Available Abstract Background A significant number of smokers would like to stop smoking. Despite the demonstrated efficacy of pharmacological smoking cessation treatments, many smokers are unwilling to use them; however, they are inclined to try alternative methods. Hypnosis has a long-standing reputation in smoking cessation therapy, but its efficacy has not been scientifically proven. We designed this randomised controlled trial to evaluate the effects of group hypnosis as a method for smoking cessation, and we will compare the results of group hypnosis with group relaxation. Methods/Design This is a randomised controlled trial (RCT to compare the efficacy of a single session of hypnosis with that of relaxation performed in groups of 8-15 smokers. We intend to include at least 220 participants in our trial. The inclusion criteria include smoking at least 5 cigarettes per day, not using other cessation methods and being willing to quit smoking. The intervention is performed by a trained hypnotist/relaxation therapist. Both groups first receive 40 min of mental preparation that is based on motivational interviewing. Then, a state of deep relaxation is induced in the hypnosis condition, and superficial relaxation is induced in the control condition. Suggestions are made in the hypnosis condition that aim to switch the mental self-image of the participants from that of smokers to that of non-smokers. Each intervention lasts for 40 min. The participants also complete questionnaires that assess their smoking status and symptoms of depression and anxiety at baseline, 2 weeks and 6 months post-intervention. In addition, saliva samples are collected to assess cotinine levels at baseline and at 6 months post-intervention. We also assess nicotine withdrawal symptoms at 2 weeks post-intervention. Discussion To the best of our knowledge, this RCT is the first to test the efficacy of group hypnosis versus group relaxation. Issues requiring discussion in the outcome

  18. The positive action conjecture and asymptotically euclidean metrics in quantum gravity

    International Nuclear Information System (INIS)

    Gibbons, G.W.; Pope, C.N.

    1979-01-01

    The positive action conjecture requires that the action of any asymptotically Euclidean 4-dimensional Riemannian metric be positive, vanishing if and only if the space is flat. Because any Ricci flat, asymptotically Euclidean metric has zero action and is local extremum of the action which is a local minimum at flat space, the conjecture requires that there are no Ricci flat asymptotically Euclidean metrics other than flat space, which would establish that flat space is the only local minimum. We prove this for metrics on R 4 and a large class of more complicated topologies and for self-dual metrics. We show that if Rsupμsubμ >= 0 there are no bound states of the Dirac equation and discuss the relevance to possible baryon non-conserving processes mediated by gravitational instantons. We conclude that these are forbidden in the lowest stationary phase approximation. We give a detailed discussion of instantons invariant under an SU(2) or SO(3) isometry group. We find all regular solutions, none of which is asymptotically Euclidean and all of which possess a further Killing vector. In an appendix we construct an approximate self-dual metric on K3 - the only simply connected compact manifold which admits a self-dual metric. (orig.) [de

  19. Asymptotic expansion and statistical description of turbulent systems

    International Nuclear Information System (INIS)

    Hagan, W.K. III.

    1986-01-01

    A new approach to studying turbulent systems is presented in which an asymptotic expansion of the general dynamical equations is performed prior to the application of statistical methods for describing the evolution of the system. This approach has been applied to two specific systems: anomalous drift wave turbulence in plasmas and homogeneous, isotropic turbulence in fluids. For the plasma case, the time and length scales of the turbulent state result in the asymptotic expansion of the Vlasov/Poisson equations taking the form of nonlinear gyrokinetic theory. Questions regarding this theory and modern Hamiltonian perturbation methods are discussed and resolved. A new alternative Hamiltonian method is described. The Eulerian Direct Interaction Approximation (EDIA) is slightly reformulated and applied to the equations of nonlinear gyrokinetic theory. Using a similarity transformation technique, expressions for the thermal diffusivity are derived from the EDIA equations for various geometries, including a tokamak. In particular, the unique result for generalized geometry may be of use in evaluating fusion reactor designs and theories of anomalous thermal transport in tokamaks. Finally, a new and useful property of the EDIA is pointed out. For the fluid case, an asymptotic expansion is applied to the Navier-Stokes equation and the results lead to the speculation that such an approach may resolve the problem of predicting the Kolmogorov inertial range energy spectrum for homogeneous, isotropic turbulence. 45 refs., 3 figs

  20. Asymptotic behaviour of a non-commutative rational series with a nonnegative linear representation

    Directory of Open Access Journals (Sweden)

    Philippe Dumas

    2007-01-01

    Full Text Available We analyse the asymptotic behaviour in the mean of a non-commutative rational series, which originates from differential cryptanalysis, using tools from probability theory, and from analytic number theory. We derive a Fourier representation of a first-order summation function obtained by interpreting this rational series as a non-classical rational sequence via the octal numeration system. The method is applicable to a wide class of sequences rational with respect to a numeration system essentially under the condition that they admit a linear representation with nonnegative coefficients.

  1. Induction motor IFOC based speed-controlled drive with asymptotic disturbance compensation

    Directory of Open Access Journals (Sweden)

    Stojić Đorđe M.

    2012-01-01

    Full Text Available This paper presents the design of digitally controlled speed electrical drive, with the asymptotic compensation of external disturbances, implemented by using the IFOC (Indirect Field Oriented Control torque controlled induction motor. The asymptotic disturbance compensation is achieved by using the DOB (Disturbance Observer with the IMP (Internal Model Principle. When compared to the existing IMP-based DOB solutions, in this paper the robust stability and disturbance compensation are improved by implementing the minimal order DOB filter. Also, the IMP-based DOB design is improved by employing the asymptotic compensation of all elemental or more complex external disturbances. The dynamic model of the IFOC torque electrical drive is, also, included in the speed-controller and DOB section design. The simulation and experimental measurements presented in the paper illustrate the effectiveness and robustness of the proposed control scheme.

  2. Methods and Algorithms for Approximating the Gamma Function and Related Functions. A survey. Part I: Asymptotic Series

    Directory of Open Access Journals (Sweden)

    Cristinel Mortici

    2015-01-01

    Full Text Available In this survey we present our recent results on analysis of gamma function and related functions. The results obtained are in the theory of asymptotic analysis, approximation of gamma and polygamma functions, or in the theory of completely monotonic functions. The motivation of this first part is the work of C. Mortici [Product Approximations via Asymptotic Integration Amer. Math. Monthly 117 (2010 434-441] where a simple strategy for constructing asymptotic series is presented. The classical asymptotic series associated to Stirling, Wallis, Glaisher-Kinkelin are rediscovered. In the second section we discuss some new inequalities related to Landau constants and we establish some asymptotic formulas.

  3. Unitarity condition in covariant quantum field theory with indefinite metric

    International Nuclear Information System (INIS)

    Slavnov, A.A.

    1989-01-01

    Conditions that ensure the existence of a unitarity S matrix acting on the subspace of states with positive norm are formulated. A study is made of BRST quantization. The only restriction on the class of theories is that the author assumes asymptotic linearization of the theory, namely, that the asymptotic dynamics is determined by a quadratic Hamiltonian. In field theory this is always the case in the framework of standard perturbation theory. However, in some models, for example, string models, and also outside the framework of perturbation theory, this condition need not be satisfied

  4. Relaxation System

    Science.gov (United States)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  5. Distributions asymptotically homogeneous along the trajectories determined by one-parameter groups

    International Nuclear Information System (INIS)

    Drozhzhinov, Yurii N; Zav'yalov, Boris I

    2012-01-01

    We give a complete description of distributions that are asymptotically homogeneous (including the case of critical index of the asymptotic scale) along the trajectories determined by continuous multiplicative one-parameter transformation groups such that the real parts of all eigenvalues of the infinitesimal matrix are positive. To do this, we introduce and study special spaces of distributions. As an application of our results, we describe distributions that are homogeneous along such groups.

  6. Cross-relaxation solid state lasers

    International Nuclear Information System (INIS)

    Antipenko, B.M.

    1989-01-01

    Cross-relaxation functional diagrams provide a high quantum efficiency for pumping bands of solid state laser media and a low waste heat. A large number of the cross-relaxation mechanisms for decay rare earth excited states in crystals have been investigated. These investigations have been a starting-point for development of the cross-relaxation solid state lasers. For example, the cross-relaxation interactions, have been used for the laser action development of LiYF 4 :Gd-Tb. These interactions are important elements of the functional diagrams of the 2 μm Ho-doped media sensitized with Er and Tm and the 3 μm Er-doped media. Recently, new efficient 2 μm laser media with cross-relaxation pumping diagrams have been developed. Physical aspects of these media are the subject of this paper. A new concept of the Er-doped medium, sensitized with Yb, is illustrated

  7. Ghost anomalous dimension in asymptotically safe quantum gravity

    International Nuclear Information System (INIS)

    Eichhorn, Astrid; Gies, Holger

    2010-01-01

    We compute the ghost anomalous dimension within the asymptotic-safety scenario for quantum gravity. For a class of covariant gauge fixings and using a functional renormalization group scheme, the anomalous dimension η c is negative, implying an improved UV behavior of ghost fluctuations. At the non-Gaussian UV fixed point, we observe a maximum value of η c ≅-0.78 for the Landau-deWitt gauge within the given scheme and truncation. Most importantly, the backreaction of the ghost flow onto the Einstein-Hilbert sector preserves the non-Gaussian fixed point with only mild modifications of the fixed-point values for the gravitational coupling and cosmological constant and the associated critical exponents; also their gauge dependence is slightly reduced. Our results provide further evidence for the asymptotic-safety scenario of quantum gravity.

  8. Hadronic Form Factors in Asymptotically Free Field Theories

    Science.gov (United States)

    Gross, D. J.; Treiman, S. B.

    1974-01-01

    The breakdown of Bjorken scaling in asymptotically free gauge theories of the strong interactions is explored for its implications on the large q{sup 2} behavior of nucleon form factors. Duality arguments of Bloom and Gilman suggest a connection between the form factors and the threshold properties of the deep inelastic structure functions. The latter are addressed directly in an analysis of asymptotically free theories; and through the duality connection we are then led to statements about the form factors. For very large q{sup 2} the form factors are predicted to fall faster than any inverse power of q{sup 2}. For the more modest range of q{sup 2} reached in existing experiments the agreement with data is fairly good, though this may well be fortuitous. Extrapolations beyond this range are presented.

  9. Molten salt reactor as asymptotic safety nuclear system

    International Nuclear Information System (INIS)

    Novikov, V.M.; Ignatyev, V.V.

    1989-01-01

    Safety is becoming the main and priority problem of the nuclear power development. An increase of the active safety measures could hardly be considered as the proper way to achieve the asymptotically high level of nuclear safety. It seem that the more realistic way to achieve such a goal is to minimize risk factors and to maximize the use of inherent and passive safety properties. The passive inherent safety features of the liquid fuel molten salt reactor (MSR) technology are making it attractive for future energy generation. The achievement of the asymptotic safety in MSR is being connected with the minimization of such risk factors as a reactivity excess, radioactivity stored, decay heat, non nuclear energy stored in core. In this paper safety peculiarities of the different MSR concepts are discussed

  10. Asymptotic matching of the solar-system gravitational yields

    International Nuclear Information System (INIS)

    Kopejkin, S.M.

    1989-01-01

    In the framework of the general relativity, the structure of the Solar-system gravitational fields is investigated and the relativistic formulae of transformation between nonrotating in the dynamical sense harmonic reference systems - barycentric, planetocentric and topocentric (satelite) ones - are derived by the method of the asymptotic mathing of components of the metric tensor. The derived formulae generalize the linear Poincare transformation in the case of curved space-time. With the help of the asymptotic matching formulae, the relationships between relativistic time scales inside the Solar system have been established, the equations of relativistic precession of the space axis of one reference system with respect to another one have been derived, the equations of translational motion of the center-of-mass of planets (the Sun) and their satellites have been obtained

  11. The Barrett–Crane model: asymptotic measure factor

    International Nuclear Information System (INIS)

    Kamiński, Wojciech; Steinhaus, Sebastian

    2014-01-01

    The original spin foam model construction for 4D gravity by Barrett and Crane suffers from a few troubling issues. In the simple examples of the vertex amplitude they can be summarized as the existence of contributions to the asymptotics from non-geometric configurations. Even restricted to geometric contributions the amplitude is not completely worked out. While the phase is known to be the Regge action, the so-called measure factor has remained mysterious for a decade. In the toy model case of the 6j symbol this measure factor has a nice geometric interpretation of V −1/2 leading to speculations that a similar interpretation should be possible also in the 4D case. In this paper we provide the first geometric interpretation of the geometric part of the asymptotic for the spin foam consisting of two glued 4-simplices (decomposition of the 4-sphere) in the Barrett–Crane model in the large internal spin regime. (paper)

  12. The Barrett-Crane model: asymptotic measure factor

    Science.gov (United States)

    Kamiński, Wojciech; Steinhaus, Sebastian

    2014-04-01

    The original spin foam model construction for 4D gravity by Barrett and Crane suffers from a few troubling issues. In the simple examples of the vertex amplitude they can be summarized as the existence of contributions to the asymptotics from non-geometric configurations. Even restricted to geometric contributions the amplitude is not completely worked out. While the phase is known to be the Regge action, the so-called measure factor has remained mysterious for a decade. In the toy model case of the 6j symbol this measure factor has a nice geometric interpretation of V-1/2 leading to speculations that a similar interpretation should be possible also in the 4D case. In this paper we provide the first geometric interpretation of the geometric part of the asymptotic for the spin foam consisting of two glued 4-simplices (decomposition of the 4-sphere) in the Barrett-Crane model in the large internal spin regime.

  13. Boundary dynamics of asymptotically flat 3D gravity coupled to higher spin fields

    International Nuclear Information System (INIS)

    González, Hernán A.; Pino, Miguel

    2014-01-01

    We construct a two-dimensional action principle invariant under a spin-three extension of BMS_3 group. Such a theory is obtained through a reduction of Chern-Simons action with a boundary. This procedure is carried out by imposing a set of boundary conditions obtained from asymptotically flat spacetimes in three dimensions. When implementing part of this set, we obtain an analog of chiral WZW model based on a contraction of sl(3,ℝ)×sl(3,ℝ). The remaining part of the boundary conditions imposes constraints on the conserved currents of the model, which allows to further reduce the action principle. It is shown that a sector of this latter theory is related to a flat limit of Toda theory

  14. Boundary dynamics of asymptotically flat 3D gravity coupled to higher spin fields

    Energy Technology Data Exchange (ETDEWEB)

    González, Hernán A. [Physique Théorique et Mathématique,Université Libre de Bruxelles & International Solvay Institutes,Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Pino, Miguel [Departamento de Física, Universidad de Santiago de Chile,Av. Ecuador 3493, Estación Central, Santiago (Chile)

    2014-05-27

    We construct a two-dimensional action principle invariant under a spin-three extension of BMS{sub 3} group. Such a theory is obtained through a reduction of Chern-Simons action with a boundary. This procedure is carried out by imposing a set of boundary conditions obtained from asymptotically flat spacetimes in three dimensions. When implementing part of this set, we obtain an analog of chiral WZW model based on a contraction of sl(3,ℝ)×sl(3,ℝ). The remaining part of the boundary conditions imposes constraints on the conserved currents of the model, which allows to further reduce the action principle. It is shown that a sector of this latter theory is related to a flat limit of Toda theory.

  15. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  16. Load dependence of left ventricular contraction and relaxation. Effects of caffeine.

    Science.gov (United States)

    Leite-Moreira, A F; Correia-Pinto, J; Gillebert, T C

    1999-08-01

    Load dependence of left ventricular (LV) contraction and relaxation was investigated at baseline and after alteration of intracellular calcium handling by caffeine. Afterload was increased by aortic clamp occlusions (n = 281) in anesthetized open-chest dogs (n = 7). Control and first heartbeat after the intervention were considered for analysis. Caffeine (50 mg/kg, iv) had no inotropic effect. The systolic LV pressure (LVP), developed in response to aortic occlusion, decreased as ejection proceeded and this pressure generating capacity was not affected by caffeine. Late-systolic aortic occlusions induced premature onset and accelerated rate of initial LVP fall at baseline and similarly after caffeine. Graded diastolic aortic occlusions induced systolic LVP elevations of various magnitudes. Smaller LVP elevations prolonged ejection and accelerated LVP fall, while larger elevations had opposite effects. The transition from acceleration to deceleration was observed at 83.1 +/- 1.1% of peak isovolumetric LVP at baseline and at lower loads, at 77.6 +/- 1.2%, after caffeine (p caffeine (p dependence of relaxation, was also modified by caffeine. Caffeine affected LV relaxation without altering contractility. As a consequence contraction-relaxation coupling was modified by caffeine. These results might help to understand load dependence of relaxation in conditions where intracellular calcium handling is altered.

  17. A Viscous Fluid Flow through a Thin Channel with Mixed Rigid-Elastic Boundary: Variational and Asymptotic Analysis

    Directory of Open Access Journals (Sweden)

    R. Fares

    2012-01-01

    Full Text Available We study the nonsteady Stokes flow in a thin tube structure composed by two thin rectangles with lateral elastic boundaries which are connected by a domain with rigid boundaries. After a variational approach of the problem which gives us existence, uniqueness, regularity results, and some a priori estimates, we construct an asymptotic solution. The existence of a junction region between the two rectangles imposes to consider, as part of the asymptotic solution, some boundary layer correctors that correspond to this region. We present and solve the problems for all the terms of the asymptotic expansion. For two different cases, we describe the order of steps of the algorithm of solving the problem and we construct the main term of the asymptotic expansion. By means of the a priori estimates, we justify our asymptotic construction, by obtaining a small error between the exact and the asymptotic solutions.

  18. Extreme-Strike and Small-time Asymptotics for Gaussian Stochastic Volatility Models

    OpenAIRE

    Zhang, Xin

    2016-01-01

    Asymptotic behavior of implied volatility is of our interest in this dissertation. For extreme strike, we consider a stochastic volatility asset price model in which the volatility is the absolute value of a continuous Gaussian process with arbitrary prescribed mean and covariance. By exhibiting a Karhunen-Loève expansion for the integrated variance, and using sharp estimates of the density of a general second-chaos variable, we derive asymptotics for the asset price density for large or smal...

  19. Large degree asymptotics of generalized Bessel polynomials

    NARCIS (Netherlands)

    J.L. López; N.M. Temme (Nico)

    2011-01-01

    textabstractAsymptotic expansions are given for large values of $n$ of the generalized Bessel polynomials $Y_n^\\mu(z)$. The analysis is based on integrals that follow from the generating functions of the polynomials. A new simple expansion is given that is valid outside a compact neighborhood of the

  20. Infrared studies of asymptotic giant branch stars

    International Nuclear Information System (INIS)

    Willems, F.J.

    1987-01-01

    In this thesis studies are presented of asymptotic giant branch stars, which are thought to be an important link in the evolution of the galaxy. The studies were performed on the basis of data collected by the IRAS, the infrared astronomical satelite. 233 refs.; 33 figs.; 16 tabs