Bethe vectors for XXX-spin chain

International Nuclear Information System (INIS)

Burdík, Čestmír; Fuksa, Jan; Isaev, Alexei

2014-01-01

The paper deals with algebraic Bethe ansatz for XXX-spin chain. Generators of Yang-Baxter algebra are expressed in basis of free fermions and used to calculate explicit form of Bethe vectors. Their relation to N-component models is used to prove conjecture about their form in general. Some remarks on inhomogeneous XXX-spin chain are included

Large N and Bethe ansatz

OpenAIRE

Jurco, B.

2003-01-01

We describe an integrable model, related to the Gaudin magnet, and its relation to the matrix model of Brezin, Itzykson, Parisi and Zuber. Relation is based on Bethe ansatz for the integrable model and its interpretation using orthogonal polynomials and saddle point approximation. Lagre $N$ limit of the matrix model corresponds to the thermodynamic limit of the integrable system. In this limit (functional) Bethe ansatz is the same as the generating function for correlators of the matrix models.

Monte Carlo study of alternate mixed spin-5/2 and spin-2 Ising ferrimagnetic system on the Bethe lattice

Energy Technology Data Exchange (ETDEWEB)

Jabar, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63 46000 Safi (Morocco); Benyoussef, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco)

2016-01-01

The magnetic properties of alternate mixed spin-5/2 and spin-2 Ising model on the Bethe lattice have been studied by using the Monte Carlo simulations. The ground state phase diagrams of alternate mixed spin-5/2 and spin-2 Ising model on the Bethe lattice has been obtained. The thermal total magnetization and magnetization of spins-5/2 and spin-2 with the different exchange interactions, external magnetic field and temperatures have been studied. The critical temperature have been deduced. The magnetic hysteresis cycle on the Bethe lattice has been deduced for different values of exchange interactions, for different values of crystal field and for different sizes. The magnetic coercive field has been deduced. - Highlights: • The alternate mixed spin-5/2 and -2 on the Bethe lattice is studied. • The critical temperature has been deduced. • The magnetic coercive filed has been deduced.

Practitioner Profile: An Interview with Beth Crittenden

Directory of Open Access Journals (Sweden)

Martie Gillen

2016-12-01

Full Text Available Beth Crittenden offers financial wellness coaching to people who want growth both professionally and personally. Beth has been working with finances as a focus since 2009, after training in somatic psychology, healthy communication in relationship, and mindful meditation practices and theory.

Where are the roots of the Bethe Ansatz equations?

Energy Technology Data Exchange (ETDEWEB)

Vieira, R.S., E-mail: rsvieira@df.ufscar.br; Lima-Santos, A., E-mail: dals@df.ufscar.br

2015-10-02

Changing the variables in the Bethe Ansatz Equations (BAE) for the XXZ six-vertex model we had obtained a coupled system of polynomial equations. This provided a direct link between the BAE deduced from the Algebraic Bethe Ansatz (ABA) and the BAE arising from the Coordinate Bethe Ansatz (CBA). For two magnon states this polynomial system could be decoupled and the solutions given in terms of the roots of some self-inversive polynomials. From theorems concerning the distribution of the roots of self-inversive polynomials we made a thorough analysis of the two magnon states, which allowed us to find the location and multiplicity of the Bethe roots in the complex plane, to discuss the completeness and singularities of Bethe's equations, the ill-founded string-hypothesis concerning the location of their roots, as well as to find an interesting connection between the BAE with Salem’s polynomials.

The Bethe wavefunction

CERN Document Server

Gaudin, Michel

2014-01-01

Michel Gaudin's book La fonction d'onde de Bethe is a uniquely influential masterpiece on exactly solvable models of quantum mechanics and statistical physics. Available in English for the first time, this translation brings his classic work to a new generation of graduate students and researchers in physics. It presents a mixture of mathematics interspersed with powerful physical intuition, retaining the author's unmistakably honest tone. The book begins with the Heisenberg spin chain, starting from the coordinate Bethe Ansatz and culminating in a discussion of its thermodynamic properties. Delta-interacting bosons (the Lieb-Liniger model) are then explored, and extended to exactly solvable models associated to a reflection group. After discussing the continuum limit of spin chains, the book covers six- and eight-vertex models in extensive detail, from their lattice definition to their thermodynamics. Later chapters examine advanced topics such as multi-component delta-interacting systems, Gaudin magnets and...

Off-diagonal Bethe ansatz for exactly solvable models

CERN Document Server

Wang, Yupeng; Cao, Junpeng; Shi, Kangjie

2015-01-01

This book serves as an introduction of the off-diagonal Bethe Ansatz method, an analytic theory for the eigenvalue problem of quantum integrable models. It also presents some fundamental knowledge about quantum integrability and the algebraic Bethe Ansatz method. Based on the intrinsic properties of R-matrix and K-matrices, the book introduces a systematic method to construct operator identities of transfer matrix.  These identities allow one to establish the inhomogeneous T-Q relation formalism to obtain Bethe Ansatz equations and to retrieve corresponding eigenstates. Several longstanding models can thus be solved via this method since the lack of obvious reference states is made up. Both the exact results and the off-diagonal Bethe Ansatz method itself may have important applications in the fields of quantum field theory, low-dimensional condensed matter physics, statistical physics and cold atom systems.

The Bethe Wavefunction

NARCIS (Netherlands)

Gaudin, M.; Caux, J.-S.

2014-01-01

Michel Gaudin's book La fonction d'onde de Bethe is a uniquely influential masterpiece on exactly solvable models of quantum mechanics and statistical physics. Available in English for the first time, this translation brings his classic work to a new generation of graduate students and researchers

Combinatorics of Generalized Bethe Equations

Science.gov (United States)

Kozlowski, Karol K.; Sklyanin, Evgeny K.

2013-10-01

A generalization of the Bethe ansatz equations is studied, where a scalar two-particle S-matrix has several zeroes and poles in the complex plane, as opposed to the ordinary single pole/zero case. For the repulsive case (no complex roots), the main result is the enumeration of all distinct solutions to the Bethe equations in terms of the Fuss-Catalan numbers. Two new combinatorial interpretations of the Fuss-Catalan and related numbers are obtained. On the one hand, they count regular orbits of the permutation group in certain factor modules over {{Z}^M}, and on the other hand, they count integer points in certain M-dimensional polytopes.

Professor Hans A Bethe

Indian Academy of Sciences (India)

2018-03-06

Mar 6, 2018 ... These theories formed the deep conceptual foundations of modern ... wrote on nuclear theory in the 1930's, often called 'Bethe's Bible', ... tions to solid state physics, fluid dynamics, shock waves, radar theory and reactor.

Time, Quantum and Information

Energy Technology Data Exchange (ETDEWEB)

Turner, Leaf [Los Alamos, New Mexico (United States)

2004-04-09

Time, Quantum and Information, a paean to Professor Carl Friedrich von Weizsaecker, commemorates his 90th birthday. The range of Professor Weizsaecker's endeavours is an exhilarating example of what can be accomplished by one freely-soaring human spirit, who is at the same time a physicist, a philosopher, and a humanitarian. The editors, Lutz Castell and Otfried Ischebeck, have assembled an admirable collection of essays and articles written by Weizsaecker?s past students, collaborators, colleagues and acquaintances. Time, Quantum and Information offers the reader a panoply of unique insights into twentieth century science and history. Entangled with the stories about Weizsaecker?s influence on the lives of some of the contributors are discussions of the activities of German scientists during and following World War II, emphasizing their reluctance to work on atomic weapons following the war. By outlining Weizsaecker?s role in the early development of numerous tributaries of physical science, the book gives us a new glimpse into the origins of some of its disparate domains, such as nuclear physics, the physics of stellar nucleosynthesis, cosmic ray physics, fluid turbulence, and the formation of the solar system. We physicists have all studied Weizsaecker?s semi-empirical mass formula describing the binding energy of nuclei. We are aware too that both he and Hans Bethe independently discovered the nuclear cycles that provide stars with their enduring energy output. We have studied the Weizsaecker--Williams technique of calculating the bremsstrahlung of relativistic electrons. But how many of us know of Weizsaecker's work in fluid turbulence that he, like Werner Heisenberg under whom he had earned his doctorate, pursued while holed up in Farm Hall? And how many of us are aware of his introduction of turbulent viscosity to account for the origin of planetary orbits, involving the migration of mass inwards and angular momentum outwards? Moreover, before

Selected Works Of Hans A Bethe (With Commentary)

International Nuclear Information System (INIS)

Bethe, Hans A.

1997-01-01

Hans A Bethe received the Nobel Prize for Physics in 1967 for his work on the production of energy in stars. A living legend among the physics community, he helped to shape classical physics into quantum physics and increased the understanding of the atomic processes responsible for the properties of matter and of the forces governing the structures of atomic nuclei. This collection of papers by Prof Bethe dates from 1928, when he received his PhD, to now. It covers several areas and reflects the many contributions in research and discovery made by one of the most important and eminent physicists of all time. Special commentaries have been written by Prof Bethe to complement the selected papers

Algebraic Bethe ansatz for the Izergin-Korepin R matrix

International Nuclear Information System (INIS)

Tarasov, V.O.

1989-01-01

The authors propose a generalization of the algebraic Bethe ansatz for the Izergin-Korepin R matrix - the simplest unstudied odd-dimensional solution of the Yang-Baxter equation - and they discuss some related questions. The first section of the paper is an introduction. In the second they indicate a way of generalizing the algebraic Bethe ansatz to the case of the Izergin-Korepin R matrix. The simplest monodromy matrices (L operators) for this R matrix are described in the third section. The fourth section is devoted to the proof of the proposed generalization of the algebraic Bethe ansatz

Centenary Birth Anniversary of E. W. Beth (1908-1964)

Science.gov (United States)

Bagni, Giorgio T.

2008-01-01

Evert Willem Beth (1908-1964) was a Dutch logician, mathematician and philosopher, whose work mainly concerned the foundations of mathematics. Beth was among the founders of the Commission Internationale pour l'Etude et l'Amelioration de l'Enseignement des Mathematiques and was a member of the Central Committee of the International Commission on…

Algebraic geometry and Bethe ansatz. Part I. The quotient ring for BAE

Science.gov (United States)

Jiang, Yunfeng; Zhang, Yang

2018-03-01

In this paper and upcoming ones, we initiate a systematic study of Bethe ansatz equations for integrable models by modern computational algebraic geometry. We show that algebraic geometry provides a natural mathematical language and powerful tools for understanding the structure of solution space of Bethe ansatz equations. In particular, we find novel efficient methods to count the number of solutions of Bethe ansatz equations based on Gröbner basis and quotient ring. We also develop analytical approach based on companion matrix to perform the sum of on-shell quantities over all physical solutions without solving Bethe ansatz equations explicitly. To demonstrate the power of our method, we revisit the completeness problem of Bethe ansatz of Heisenberg spin chain, and calculate the sum rules of OPE coefficients in planar N=4 super-Yang-Mills theory.

Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

Energy Technology Data Exchange (ETDEWEB)

Cirilo António, N., E-mail: nantonio@math.ist.utl.pt [Centro de Análise Funcional e Aplicações, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Manojlović, N., E-mail: nmanoj@ualg.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Prof. Gama Pinto 2, PT-1649-003 Lisboa (Portugal); Departamento de Matemática, F.C.T., Universidade do Algarve, Campus de Gambelas, PT-8005-139 Faro (Portugal); Salom, I., E-mail: isalom@ipb.ac.rs [Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)

2014-12-15

We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

Science.gov (United States)

Cirilo António, N.; Manojlović, N.; Salom, I.

2014-12-01

We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

Time, Quantum and Information

International Nuclear Information System (INIS)

Turner, Leaf

2004-01-01

Time, Quantum and Information, a paean to Professor Carl Friedrich von Weizsaecker, commemorates his 90th birthday. The range of Professor Weizsaecker's endeavours is an exhilarating example of what can be accomplished by one freely-soaring human spirit, who is at the same time a physicist, a philosopher, and a humanitarian. The editors, Lutz Castell and Otfried Ischebeck, have assembled an admirable collection of essays and articles written by Weizsaecker?s past students, collaborators, colleagues and acquaintances. Time, Quantum and Information offers the reader a panoply of unique insights into twentieth century science and history. Entangled with the stories about Weizsaecker?s influence on the lives of some of the contributors are discussions of the activities of German scientists during and following World War II, emphasizing their reluctance to work on atomic weapons following the war. By outlining Weizsaecker?s role in the early development of numerous tributaries of physical science, the book gives us a new glimpse into the origins of some of its disparate domains, such as nuclear physics, the physics of stellar nucleosynthesis, cosmic ray physics, fluid turbulence, and the formation of the solar system. We physicists have all studied Weizsaecker?s semi-empirical mass formula describing the binding energy of nuclei. We are aware too that both he and Hans Bethe independently discovered the nuclear cycles that provide stars with their enduring energy output. We have studied the Weizsaecker--Williams technique of calculating the bremsstrahlung of relativistic electrons. But how many of us know of Weizsaecker's work in fluid turbulence that he, like Werner Heisenberg under whom he had earned his doctorate, pursued while holed up in Farm Hall? And how many of us are aware of his introduction of turbulent viscosity to account for the origin of planetary orbits, involving the migration of mass inwards and angular momentum outwards? Moreover, before finally

A universality test of the quantum string Bethe ansatz

DEFF Research Database (Denmark)

Freyhult, L.; Kristjansen, C.

2006-01-01

We show that the quantum corrected string Bethe ansatz passes an important universality test by demonstrating that it correctly incorporates the non-analytical terms in the string sigma model one-loop correction for rational three-spin strings with two out of the three spins identical. Subsequent......, we use the quantum corrected string Bethe ansatz to predict the exact form of the non-analytic terms for the generic rational three-spin string.......We show that the quantum corrected string Bethe ansatz passes an important universality test by demonstrating that it correctly incorporates the non-analytical terms in the string sigma model one-loop correction for rational three-spin strings with two out of the three spins identical. Subsequently...

Bethe-Salpeter amplitudes and static properties of the deuteron

International Nuclear Information System (INIS)

Kaptari, L.P.; Bondarenko, S.G.; Khanna, F.C.; Kaempfer, B.; Technische Univ. Dresden

1996-04-01

Extended calculations of the deuteron's static properties, based on the numerical solution of the Bethe-Salpeter equation, are presented. A formalism is developed, which provides a comparative analysis of the covariant amplitudes in various representations and nonrelativistic wave functions. The magnetic and quadrupole moments of the deuteron are calculated in the Bethe-Salpeter formalism and the role of relativistic corrections is discussed. (orig.)

Obituary: Beth Brown (1969-2008)

Science.gov (United States)

Bregman, Joel

2011-12-01

The astronomical community lost one of its most buoyant and caring individuals when Beth Brown died, unexpectedly, at the age of 39 from a pulmonary embolism. Beth Brown was born in Roanoke, Virginia where she developed a deep interest in astronomy, science, and science fiction (Star Trek). After graduating as the valedictorian of William Fleming High School's Class of 1987, she attended Howard University, where she graduated summa cum laude in 1991 with a bachelor's degree in astrophysics. Following a year in the graduate physics program at Howard, she entered the graduate program in the Department of Astronomy at the University of Michigan, the first African-American woman in the program. She received her PhD in 1998, working with X-ray observations of elliptical galaxies from the Röntgen Satellite (ROSAT; Joel Bregman was her advisor). She compiled and analyzed the first large complete sample of such galaxies with ROSAT and her papers in this area made an impact in the field. Following her PhD, Beth Brown held a National Academy of Science & National Research Council Postdoctoral Research Fellowship at NASA's Goddard Space Flight Center. Subsequently, she became a civil servant at the National Space Science Data Center at GSFC, where she was involved in data archival activities as well as education and outreach, a continuing passion in her life. In 2006, Brown became an Astrophysics Fellow at GSFC, during which time she worked as a visiting Assistant Professor at Howard University, where she taught and worked with students and faculty to improve the teaching observatory. At the time of her death, she was eagerly looking forward to a new position at GSFC as the Assistant Director for Science Communications and Higher Education. Beth Brown was a joyous individual who loved to work with people, especially in educating them about our remarkable field. Her warmth and openness was a great aid in making accessible explanations of otherwise daunting astrophysical

Algebraic Bethe ansatz for 19-vertex models with reflection conditions

International Nuclear Information System (INIS)

Utiel, Wagner

2003-01-01

In this work we solve the 19-vertex models with the use of algebraic Bethe ansatz for diagonal reflection matrices (Sklyanin K-matrices). The eigenvectors, eigenvalues and Bethe equations are given in a general form. Quantum spin chains of spin one derived from the 19-vertex models were also discussed

Extreme exotic calcium lambda hypernuclei in the relativistic continuum Hartree-Bogoliubov theory

International Nuclear Information System (INIS)

Lv Hongfeng

2008-01-01

Exotic calcium lambda hypernuclei properties with the neutron number of 20-400 by a step of 20 are discussed by employing the relativistic continuum Hartree-Bogoliubov theory with a zero range pairing interaction. The Bethe-Weizsaecker mass formula of a multi-strange system and the Woods-Saxon-type potential of lambda need to be modified for exotic calcium hypernuclei with unusual number of neutrons and lambdas. The possible neutron and lambda limits of exotic Ca lambda hypernuclei are also investigated. (authors)

Overlaps of partial Néel states and Bethe states

International Nuclear Information System (INIS)

Foda, O; Zarembo, K

2016-01-01

Partial Néel states are generalizations of the ordinary Néel (classical anti-ferromagnet) state that can have arbitrary integer spin. We study overlaps of these states with Bethe states. We first identify this overlap with a partial version of reflecting-boundary domain-wall partition function, and then derive various determinant representations for off-shell and on-shell Bethe states. (paper: quantum statistical physics, condensed matter, integrable systems)

Two site spin correlation function in Bethe-Peierls approximation for Ising model

Energy Technology Data Exchange (ETDEWEB)

Kumar, D [Roorkee Univ. (India). Dept. of Physics

1976-07-01

Two site spin correlation function for an Ising model above Curie temperature has been calculated by generalising Bethe-Peierls approximation. The results derived by a graphical method due to Englert are essentially the same as those obtained earlier by Elliott and Marshall, and Oguchi and Ono. The earlier results were obtained by a direct generalisation of the cluster method of Bethe, while these results are derived by retaining that class of diagrams , which is exact on Bethe lattice.

Heisenberg XXX Model with General Boundaries: Eigenvectors from Algebraic Bethe Ansatz

Directory of Open Access Journals (Sweden)

Samuel Belliard

2013-11-01

Full Text Available We propose a generalization of the algebraic Bethe ansatz to obtain the eigenvectors of the Heisenberg spin chain with general boundaries associated to the eigenvalues and the Bethe equations found recently by Cao et al. The ansatz takes the usual form of a product of operators acting on a particular vector except that the number of operators is equal to the length of the chain. We prove this result for the chains with small length. We obtain also an off-shell equation (i.e. satisfied without the Bethe equations formally similar to the ones obtained in the periodic case or with diagonal boundaries.

The role of the von Weizsaecker kinetic energy gradient term in independent harmonically confined fermions for arbitrary two-dimensional closed-shell occupancy

International Nuclear Information System (INIS)

Howard, I A; March, N H

2010-01-01

The search for the single-particle kinetic energy functional T S [n] continues to be of major interest for density functional theory. Since it is expected to be generally applicable, exactly solvable models are of obvious interest. Here we focus on one, which is also of interest experimentally in magnetic trapping of ultracold fermion vapours. This is the model of independent harmonically trapped fermions in two dimensions. Here, the role of the von Weizsaecker inhomogeneity kinetic energy is a focal point, prompted also by the work of Delle Site (2005 J. Phys. A: Math. Gen. 38 7893).

Bethe states of the trigonometric SU(3) spin chain with generic open boundaries

Science.gov (United States)

Sun, Pei; Xin, Zhirong; Qiao, Yi; Wen, Fakai; Hao, Kun; Cao, Junpeng; Li, Guang-Liang; Yang, Tao; Yang, Wen-Li; Shi, Kangjie

2018-06-01

By combining the algebraic Bethe ansatz and the off-diagonal Bethe ansatz, we investigate the trigonometric SU (3) model with generic open boundaries. The eigenvalues of the transfer matrix are given in terms of an inhomogeneous T - Q relation, and the corresponding eigenstates are expressed in terms of nested Bethe-type eigenstates which have well-defined homogeneous limit. This exact solution provides a basis for further analyzing the thermodynamic properties and correlation functions of the anisotropic models associated with higher rank algebras.

Degeneration of Bethe subalgebras in the Yangian of gl_n

Science.gov (United States)

Ilin, Aleksei; Rybnikov, Leonid

2018-04-01

We study degenerations of Bethe subalgebras B( C) in the Yangian Y(gl_n), where C is a regular diagonal matrix. We show that closure of the parameter space of the family of Bethe subalgebras, which parameterizes all possible degenerations, is the Deligne-Mumford moduli space of stable rational curves \\overline{M_{0,n+2}}. All subalgebras corresponding to the points of \\overline{M_{0,n+2}} are free and maximal commutative. We describe explicitly the "simplest" degenerations and show that every degeneration is the composition of the simplest ones. The Deligne-Mumford space \\overline{M_{0,n+2}} generalizes to other root systems as some De Concini-Procesi resolution of some toric variety. We state a conjecture generalizing our results to Bethe subalgebras in the Yangian of arbitrary simple Lie algebra in terms of this De Concini-Procesi resolution.

On the completeness of the set of Bethe-Hulthen solutions of the linear Heisenberg system

International Nuclear Information System (INIS)

Caspers, W J; Labuz, M; Wal, A

2006-01-01

In this work we formulate the standard form of the solutions of the Heisenberg chain with periodic boundary conditions and show that these solutions can be transformed into the well-known Bethe-Hulthen solutions. The standard form is found by solving the secular problem, separated according to the irreducible representations of the translation group. The relevant parameters exp(ik j ) of the Bethe-Hulthen solutions are found from a set of linear equations with coefficients derived from the standard solutions. This correspondence between standard and Bethe-Hulthen solutions realizes the completeness of the Bethe-Hulthen method

Colored Quantum Algebra and Its Bethe State

International Nuclear Information System (INIS)

Wang Jin-Zheng; Jia Xiao-Yu; Wang Shi-Kun

2014-01-01

We investigate the colored Yang—Baxter equation. Based on a trigonometric solution of colored Yang—Baxter equation, we construct a colored quantum algebra. Moreover we discuss its algebraic Bethe ansatz state and highest wight representation. (general)

Bethe ansatz solution of the closed anisotropic supersymmetric U model with quantum supersymmetry

International Nuclear Information System (INIS)

Hibberd, Katrina; Roditi, Itzhak; Links, Jon; Foerster, Angela

1999-11-01

The nested algebraic Bethe Ansatz is presented for the anisotropic supersymmetric U model maintaining quantum a supersymmetry. The Bethe Ansatz equations of the model are obtained on a one-dimensional closed lattice and an expression for the energy is given. (author)

The Yangians, Bethe ansatz and combinatorics

International Nuclear Information System (INIS)

Kirillov, A.N.; Reshetikhin, N.Yu.

1986-01-01

An axiomatic definition of a quantum monodromy matrix and the representations of its corresponding Hopf algebra are discussed. The connection between the quantum inverse transform method and the representation theory of a symmetric group is considered. A new approach to the completeness problem of Bethe vectors is also given. (orig.)

Quantum Waveguide Properties of Bethe Lattices with a Ring

International Nuclear Information System (INIS)

Zhi-Ping, Lin; Zhi-Lin, Hou; You-Yan, Liu

2008-01-01

Based on waveguide theory we investigate electronic transport properties of Bethe lattices with a mesoscopic ring threaded by a magnetic flux. The generalized eigen-function method (GEM) is used to calculate the transmission and reflection coefficients up to the fifth generation of Bethe lattices. The relationships among the transmission coefficient T, magnetic flux φ and wave vector kl are investigated in detail. The numerical results are shown by the three-dimensional plots and contour maps. Some resonant-transmission features and the symmetry of the transmission coefficient T to flux φ are observed and discussed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Obituary: Hans Albrecht Bethe, 1906-2005

NARCIS (Netherlands)

Wijers, R.

2007-01-01

One of the unquestioned giants of physics and astrophysics, Hans Bethe, died on 6 March 2005, at the venerable age of 98, in his home town of Ithaca, New York. Seven decades of contributing to research and a Nobel Prize for his work on stellar hydrogen burning make a listing of his honors

Approximate, analytic solutions of the Bethe equation for charged particle range

OpenAIRE

Swift, Damian C.; McNaney, James M.

2009-01-01

By either performing a Taylor expansion or making a polynomial approximation, the Bethe equation for charged particle stopping power in matter can be integrated analytically to obtain the range of charged particles in the continuous deceleration approximation. Ranges match reference data to the expected accuracy of the Bethe model. In the non-relativistic limit, the energy deposition rate was also found analytically. The analytic relations can be used to complement and validate numerical solu...

Glueball properties from the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Kellermann, Christian

2012-01-01

For over thirty years bound states of gluons are an outstanding problem of both theoretical and experimental physics. Being predicted by Quantum-Chromodynamics their experimental confirmation is one of the foremost goals of large experimental facilities currently under construction like FAIR in Darmstadt. This thesis presents a novel approach to the theoretical determination of physical properties of bound states of two gluons, called glueballs. It uses the consistent combination of Schwinger-Dyson equations for gluons and ghosts and appropriate Bethe-Salpeter equations describing their corresponding bound-states. A rigorous derivation of both sets of equations, starting from an 2PI effective action is given as well as a general determination of appropriate decompositions of Bethe-Salpeter amplitudes to a given set of quantum numbers of a glueball. As an application example bound state masses of glueballs in a simple truncation scheme are calculated. (orig.)

Algebraic Bethe ansatz for the XXZ Heisenberg spin chain with triangular boundaries and the corresponding Gaudin model

Science.gov (United States)

Manojlović, N.; Salom, I.

2017-10-01

The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.

Algebraic Bethe ansatz for the XXZ Heisenberg spin chain with triangular boundaries and the corresponding Gaudin model

International Nuclear Information System (INIS)

Manojlović, N.; Salom, I.

2017-01-01

The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.

Approach to kinetic energy density functionals: Nonlocal terms with the structure of the von Weizsaecker functional

International Nuclear Information System (INIS)

Garcia-Aldea, David; Alvarellos, J. E.

2008-01-01

We propose a kinetic energy density functional scheme with nonlocal terms based on the von Weizsaecker functional, instead of the more traditional approach where the nonlocal terms have the structure of the Thomas-Fermi functional. The proposed functionals recover the exact kinetic energy and reproduce the linear response function of homogeneous electron systems. In order to assess their quality, we have tested the total kinetic energies as well as the kinetic energy density for atoms. The results show that these nonlocal functionals give as good results as the most sophisticated functionals in the literature. The proposed scheme for constructing the functionals means a step ahead in the field of fully nonlocal kinetic energy functionals, because they are capable of giving better local behavior than the semilocal functionals, yielding at the same time accurate results for total kinetic energies. Moreover, the functionals enjoy the possibility of being evaluated as a single integral in momentum space if an adequate reference density is defined, and then quasilinear scaling for the computational cost can be achieved

Pionierin der Religionspsychologie: Marianne Beth (1890-1984)

NARCIS (Netherlands)

Belzen, J.A.

2010-01-01

This article deals with the contributions to the psychology of religion made by Dr. Marianne Beth (1890-1984), an almost totally forgotten pioneer of the psychology of religion. The article especially contextualizes her initiative to turn "unbelief" into a topic for research in psychology of

A cluster-bethe-lattice approach to spin-waves in dilute ferromagnets

International Nuclear Information System (INIS)

Salzberg, J.B.; Silva, C.E.T.G. da; Falicov, L.M.

1975-01-01

The spin-wave spectra of a dilute ferromagnet within the cluster-bethe-lattice approximation is studied. Short range order effects for the alloy are included. A study of finite size clusters connected at their edges to Bethe lattices of the same coordination number allows one to determine:(i) the stability condition for the magnetic system; (ii) the continuum spin-wave local density of states and (iii) the existence of localized states below and above the continuum states

Model of pair aggregation on the Bethe lattice

DEFF Research Database (Denmark)

Baillet, M.V.-P.; Pacheco, A.F.; Gómez, J.B.

1997-01-01

We extend a recent model of aggregation of pairs of particles, analyzing the case in which the supporting framework is a Bethe lattice. The model exhibits a critical behavior of the percolation theory type....

Euclidean to Minkowski Bethe-Salpeter amplitude and observables

International Nuclear Information System (INIS)

Carbonell, J.; Frederico, T.; Karmanov, V.A.

2017-01-01

We propose a method to reconstruct the Bethe-Salpeter amplitude in Minkowski space given the Euclidean Bethe-Salpeter amplitude - or alternatively the light-front wave function - as input. The method is based on the numerical inversion of the Nakanishi integral representation and computing the corresponding weight function. This inversion procedure is, in general, rather unstable, and we propose several ways to considerably reduce the instabilities. In terms of the Nakanishi weight function, one can easily compute the BS amplitude, the LF wave function and the electromagnetic form factor. The latter ones are very stable in spite of residual instabilities in the weight function. This procedure allows both, to continue the Euclidean BS solution in the Minkowski space and to obtain a BS amplitude from a LF wave function. (orig.)

Euclidean to Minkowski Bethe-Salpeter amplitude and observables

Energy Technology Data Exchange (ETDEWEB)

Carbonell, J. [Universite Paris-Sud, IN2P3-CNRS, Institut de Physique Nucleaire, Orsay Cedex (France); Frederico, T. [Instituto Tecnologico de Aeronautica, DCTA, Sao Jose dos Campos (Brazil); Karmanov, V.A. [Lebedev Physical Institute, Moscow (Russian Federation)

2017-01-15

We propose a method to reconstruct the Bethe-Salpeter amplitude in Minkowski space given the Euclidean Bethe-Salpeter amplitude - or alternatively the light-front wave function - as input. The method is based on the numerical inversion of the Nakanishi integral representation and computing the corresponding weight function. This inversion procedure is, in general, rather unstable, and we propose several ways to considerably reduce the instabilities. In terms of the Nakanishi weight function, one can easily compute the BS amplitude, the LF wave function and the electromagnetic form factor. The latter ones are very stable in spite of residual instabilities in the weight function. This procedure allows both, to continue the Euclidean BS solution in the Minkowski space and to obtain a BS amplitude from a LF wave function. (orig.)

Algebraic Bethe ansatz for the XXZ Heisenberg spin chain with triangular boundaries and the corresponding Gaudin model

Directory of Open Access Journals (Sweden)

N. Manojlović

2017-10-01

Full Text Available The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.

A Political End to a Pioneering Career: Marianne Beth and the Psychology of Religion

Directory of Open Access Journals (Sweden)

Jacob A. Belzen

2011-07-01

Full Text Available Although forgotten in both Religionswissenschaft (the Science of Religion and psychology, Marianne Beth (1880-1984, initially trained as a lawyer and already in 1928 called a “leading European woman”, must be considered as one of the female pioneers of these fields. She has been active especially in the psychology of religion, a field in which she, together with her husband Karl Beth, founded a research institute, an international organization and a journal. In 1932, the Beths organized in Vienna (where Karl was a professor the largest conference ever in the history of the psychology of religion. Because of her Jewish descent, Marianne Beth fled to the USA when Austria was annexed by Nazi Germany in 1938. This brought an abrupt end to her career as researcher and writer. The article reconstructs Marianne Beth’s path into psychology, analyzes some of her work and puts her achievements in an international perspective.

Introduction to the thermodynamic Bethe ansatz

Science.gov (United States)

van Tongeren, Stijn J.

2016-08-01

We give a pedagogical introduction to the thermodynamic Bethe ansatz, a method that allows us to describe the thermodynamics of integrable models whose spectrum is found via the (asymptotic) Bethe ansatz. We set the stage by deriving the Fermi-Dirac distribution and associated free energy of free electrons, and then in a similar though technically more complicated fashion treat the thermodynamics of integrable models, focusing first on the one-dimensional Bose gas with delta function interaction as a clean pedagogical example, secondly the XXX spin chain as an elementary (lattice) model with prototypical complicating features in the form of bound states, and finally the {SU}(2) chiral Gross-Neveu model as a field theory example. Throughout this discussion we emphasize the central role of particle and hole densities, whose relations determine the model under consideration. We then discuss tricks that allow us to use the same methods to describe the exact spectra of integrable field theories on a circle, in particular the chiral Gross-Neveu model. We moreover discuss the simplification of TBA equations to Y systems, including the transition back to integral equations given sufficient analyticity data, in simple examples.

Norm of Bethe vectors in models with gl(m|n symmetry

Directory of Open Access Journals (Sweden)

A. Hutsalyuk

2018-01-01

Full Text Available We study quantum integrable models solvable by the nested algebraic Bethe ansatz and possessing gl(m|n-invariant R-matrix. We compute the norm of the Hamiltonian eigenstates. Using the notion of a generalized model we show that the square of the norm obeys a number of properties that uniquely fix it. We also show that a Jacobian of the system of Bethe equations obeys the same properties. In this way we prove a generalized Gaudin hypothesis for the norm of the Hamiltonian eigenstates.

On the energy spectrum of the Bethe-Salpeter equation; Ob ehnergeticheskom spektre uravneniya Bete-Solpitera

Energy Technology Data Exchange (ETDEWEB)

Dorkin, S M [Dal` nevostochnyj Gosudarstvennyj Univ., Vladivostok (Russian Federation); Kaptar` , L P; Semikh, S S [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics

1997-12-31

The problem of calculating the energy spectrum of a two-fermion bound state within the Bethe-Salpeter formalism is discussed. An expansion of the kernel of the spinor-spinor Bethe-Salpeter equation in the ladder approximation is found in terms of a bi-orthogonal basis of the generalized Gilbert-Schmidt series for symmetric equations of the Fredholm type. According to this expansion, a new method of solving the Bethe-Salpeter equation and finding the mass spectrum is proposed. Methodological result of numerical solutions of equations with scalar interaction is presented. (author). 20 refs., 3 figs.

Off-diagonal Bethe ansatz solution of the XXX spin chain with arbitrary boundary conditions

Energy Technology Data Exchange (ETDEWEB)

Cao, Junpeng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Wen-Li, E-mail: wlyang@nwu.edu.cn [Institute of Modern Physics, Northwest University, Xian 710069 (China); Shi, Kangjie [Institute of Modern Physics, Northwest University, Xian 710069 (China); Wang, Yupeng, E-mail: yupeng@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2013-10-01

Employing the off-diagonal Bethe ansatz method proposed recently by the present authors, we exactly diagonalize the XXX spin chain with arbitrary boundary fields. By constructing a functional relation between the eigenvalues of the transfer matrix and the quantum determinant, the associated T–Q relation and the Bethe ansatz equations are derived.

Off-diagonal Bethe ansatz solution of the XXX spin chain with arbitrary boundary conditions

International Nuclear Information System (INIS)

Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

2013-01-01

Employing the off-diagonal Bethe ansatz method proposed recently by the present authors, we exactly diagonalize the XXX spin chain with arbitrary boundary fields. By constructing a functional relation between the eigenvalues of the transfer matrix and the quantum determinant, the associated T–Q relation and the Bethe ansatz equations are derived

Hans Bethe, Quantum Mechanics, and the Lamb Shift

Indian Academy of Sciences (India)

addressed by Bethe in his own inimitable style: He was returning to ... the solution in the train itself (!), on his return journey ... was a viable atomic model to account for some cru- ... The WS conditions in turn were based on the Hamilton-.

GW and Bethe-Salpeter study of small water clusters

Energy Technology Data Exchange (ETDEWEB)

Blase, Xavier, E-mail: xavier.blase@neel.cnrs.fr; Boulanger, Paul [CNRS, Institut NEEL, F-38042 Grenoble (France); Bruneval, Fabien [CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette (France); Fernandez-Serra, Marivi [Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800 (United States); Institute for Advanced Computational Sciences, Stony Brook University, Stony Brook, New York 11794-3800 (United States); Duchemin, Ivan [INAC, SP2M/L-Sim, CEA/UJF Cedex 09, 38054 Grenoble (France)

2016-01-21

We study within the GW and Bethe-Salpeter many-body perturbation theories the electronic and optical properties of small (H{sub 2}O){sub n} water clusters (n = 1-6). Comparison with high-level CCSD(T) Coupled-Cluster at the Single Double (Triple) levels and ADC(3) Green’s function third order algebraic diagrammatic construction calculations indicates that the standard non-self-consistent G{sub 0}W{sub 0}@PBE or G{sub 0}W{sub 0}@PBE0 approaches significantly underestimate the ionization energy by about 1.1 eV and 0.5 eV, respectively. Consequently, the related Bethe-Salpeter lowest optical excitations are found to be located much too low in energy when building transitions from a non-self-consistent G{sub 0}W{sub 0} description of the quasiparticle spectrum. Simple self-consistent schemes, with update of the eigenvalues only, are shown to provide a weak dependence on the Kohn-Sham starting point and a much better agreement with reference calculations. The present findings rationalize the theory to experiment possible discrepancies observed in previous G{sub 0}W{sub 0} and Bethe-Salpeter studies of bulk water. The increase of the optical gap with increasing cluster size is consistent with the evolution from gas to dense ice or water phases and results from an enhanced screening of the electron-hole interaction.

Bethe ansatz solutions of the τ{sub 2}-model with arbitrary boundary fields

Energy Technology Data Exchange (ETDEWEB)

Xu, Xiaotian; Hao, Kun; Yang, Tao [Institute of Modern Physics, Northwest University,Xian 710069 (China); Shaanxi Key Laboratory for Theoretical Physics Frontiers,Xian 710069 (China); Cao, Junpeng [Beijing National Laboratory for Condensed Matter Physics,Institute of Physics, Chinese Academy of Sciences,Beijing 100190 (China); Collaborative Innovation Center of Quantum Matter,Beijing (China); School of Physical Sciences, University of Chinese Academy of Sciences,Beijing (China); Yang, Wen-Li [Institute of Modern Physics, Northwest University,Xian 710069 (China); Shaanxi Key Laboratory for Theoretical Physics Frontiers,Xian 710069 (China); Beijing Center for Mathematics and Information Interdisciplinary Sciences,Beijing, 100048 (China); Shi, Kangjie [Institute of Modern Physics, Northwest University,Xian 710069 (China); Shaanxi Key Laboratory for Theoretical Physics Frontiers,Xian 710069 (China)

2016-11-11

The quantum τ{sub 2}-model with generic site-dependent inhomogeneity and arbitrary boundary fields is studied via the off-diagonal Bethe Ansatz method. The eigenvalues of the corresponding transfer matrix are given in terms of an inhomogeneous T−Q relation, which is based on the operator product identities among the fused transfer matrices and the asymptotic behavior of the transfer matrices. Moreover, the associated Bethe Ansatz equations are also obtained.

Validity of various approximations for the Bethe-Salpeter equation and their WKB quantization

International Nuclear Information System (INIS)

Silvestre-Brac, B.; Bilal, A.; Gignoux, C.; Schuck, P.

1984-01-01

The validity of the instantaneous approximation for the Bethe-Salpeter equation is questioned within the framework of the simple scalar-scalar model of Cutkosky. Detailed numerous results for various approximations are compared to the exact ones. WKB quantization is applied to these relativistic approximations. An unexpected question arises: is the currently used Bethe-Salpeter equation (i.e., the ladder approximation) well suited to describe two interacting relativistic particles

Bethe ansatz approach to quantum sine Gordon thermodynamics and finite temperature excitations

International Nuclear Information System (INIS)

Zotos, X.

1982-01-01

Takahashi and Suzuki (TS) using the Bethe ansatz method developed a formalism for the thermodynamics of the XYZ spin chain. Translating their formalism to the quantum sine-Gordon system, the thermodynamics and finite temperature elementary excitations are analyzed. Criteria imposed by TS on the allowed states simply correspond to the condition of normalizability of the wave functions. A set of coupled nonlinear integral equations for the thermodynamic equilibrium densities for particular values of the coupling constant in the attractive regime is derived. Solving numerically these Bethe ansatz equations, curves of the specific heat as a function of temperature are obtained. The soliton contribution peaks at a temperature of about 0.4 soliton masses shifting downward as the classical limit is approached. The weak coupling regime is analyzed by deriving the Bethe ansatz equations including the charged vacuum excitations. It is shown that they are necessary for a consistent presentation of the thermodynamics

The Bethe Sum Rule and Basis Set Selection in the Calculation of Generalized Oscillator Strengths

DEFF Research Database (Denmark)

Cabrera-Trujillo, Remigio; Sabin, John R.; Oddershede, Jens

1999-01-01

Fulfillment of the Bethe sum rule may be construed as a measure of basis set quality for atomic and molecular properties involving the generalized oscillator strength distribution. It is first shown that, in the case of a complete basis, the Bethe sum rule is fulfilled exactly in the random phase...

Loop expansion around the Bethe approximation through the M-layer construction

Science.gov (United States)

Altieri, Ada; Chiara Angelini, Maria; Lucibello, Carlo; Parisi, Giorgio; Ricci-Tersenghi, Federico; Rizzo, Tommaso

2017-11-01

For every physical model defined on a generic graph or factor graph, the Bethe M-layer construction allows building a different model for which the Bethe approximation is exact in the large M limit, and coincides with the original model for M=1 . The 1/M perturbative series is then expressed by a diagrammatic loop expansion in terms of so-called fat diagrams. Our motivation is to study some important second-order phase transitions that do exist on the Bethe lattice, but are either qualitatively different or absent in the corresponding fully connected case. In this case, the standard approach based on a perturbative expansion around the naive mean field theory (essentially a fully connected model) fails. On physical grounds, we expect that when the construction is applied to a lattice in finite dimension there is a small region of the external parameters, close to the Bethe critical point, where strong deviations from mean-field behavior will be observed. In this region, the 1/M expansion for the corrections diverges, and can be the starting point for determining the correct non-mean-field critical exponents using renormalization group arguments. In the end, we will show that the critical series for the generic observable can be expressed as a sum of Feynman diagrams with the same numerical prefactors of field theories. However, the contribution of a given diagram is not evaluated by associating Gaussian propagators to its lines, as in field theories: one has to consider the graph as a portion of the original lattice, replacing the internal lines with appropriate one-dimensional chains, and attaching to the internal points the appropriate number of infinite-size Bethe trees to restore the correct local connectivity of the original model. The actual contribution of each (fat) diagram is the so-called line-connected observable, which also includes contributions from sub-diagrams with appropriate prefactors. In order to compute the corrections near to the critical

ODE/IM correspondence and Bethe ansatz for affine Toda field equations

Directory of Open Access Journals (Sweden)

Katsushi Ito

2015-07-01

Full Text Available We study the linear problem associated with modified affine Toda field equation for the Langlands dual gˆ∨, where gˆ is an untwisted affine Lie algebra. The connection coefficients for the asymptotic solutions of the linear problem are found to correspond to the Q-functions for g-type quantum integrable models. The ψ-system for the solutions associated with the fundamental representations of g leads to Bethe ansatz equations associated with the affine Lie algebra gˆ. We also study the A2r(2 affine Toda field equation in massless limit in detail and find its Bethe ansatz equations as well as T–Q relations.

Generalized Bethe-Negele inequalities for excited states in muonic atoms

International Nuclear Information System (INIS)

Klarsfeld, S.

1976-11-01

Rigorous upper and lower bounds are derived for the Bethe logarithms in excited states of muonic atoms. Comparison with previous empirical estimates shows that the latter are inadequate in certain cases

Excited charmonium states from Bethe-Salpeter Equation

Czech Academy of Sciences Publication Activity Database

Šauli, Vladimír; Bicudo, P.

2012-01-01

Roč. 7, 043 (2012), s. 1-10 ISSN 1824-8039. [International Workshop on QCD Green’s Functions. Tranto, 05.09.2011-09.09.2011] R&D Projects: GA MŠk(CZ) LG11005 Institutional research plan: CEZ:AV0Z10480505 Keywords : charmonium * Bethe-Salpeter Equation Subject RIV: BE - Theoretical Physics http:// pos .sissa.it/archive/conferences/136/043/QCD-TNT-II_043.pdf

The History and Impact of the CNO Cycles in Nuclear Astrophysics

Science.gov (United States)

Wiescher, Michael

2018-03-01

The carbon cycle, or Bethe-Weizsäcker cycle, plays an important role in astrophysics as one of the most important energy sources for quiescent and explosive hydrogen burning in stars. This paper presents the intellectual and historical background of the idea of the correlation between stellar energy production and the synthesis of the chemical elements in stars on the example of this cycle. In particular, it addresses the contributions of Carl Friedrich von Weizsäcker and Hans Bethe, who provided the first predictions of the carbon cycle. Further, the experimental verification of the predicted process as it developed over the following decades is discussed, as well as the extension of the initial carbon cycle to the carbon-nitrogen-oxygen (CNO) multi-cycles and the hot CNO cycles. This development emerged from the detailed experimental studies of the associated nuclear reactions over more than seven decades. Finally, the impact of the experimental and theoretical results on our present understanding of hydrogen burning in different stellar environments is presented, as well as the impact on our understanding of the chemical evolution of our universe.

Thermodynamic Bethe ansatz with Haldane statistics

International Nuclear Information System (INIS)

Bytsko, A.G.; Fring, A.

1998-01-01

We derive the thermodynamic Bethe ansatz equation for the situation in which the statistical interaction of a multi-particle system is governed by Haldane statistics. We formulate a macroscopical equivalence principle for such systems. Particular CDD ambiguities play a distinguished role in compensating the ambiguity in the exclusion statistics. We derive Y-systems related to generalized statistics. We discuss several fermionic, bosonic and anyonic versions of affine Toda field theories and Calogero-Sutherland type models in the context of generalized statistics. (orig.)

Cluster-Bethe-Lattice study of a planar antiferromagnet: Rb2NiF4

International Nuclear Information System (INIS)

Cruz, G.A.C. de la; Silva, C.E.T.G. da

1979-01-01

A discussion of the Cluster-Bethe-Lattice method is presented for a planar antiferromagnet for which the hamiltonian parameters are known and the one-magnon density of states may be computed exactly. All the square clusters of 1 to 121 atoms are studied both connected to and isolated from the Bethe lattices. It is shown that, even for the largest cluster treated, the approximation is still far from the exact result. It is discussed the limitations of the method [pt

Bayesian extraction of the parton distribution amplitude from the Bethe-Salpeter wave function

Science.gov (United States)

Gao, Fei; Chang, Lei; Liu, Yu-xin

2017-07-01

We propose a new numerical method to compute the parton distribution amplitude (PDA) from the Euclidean Bethe-Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe-Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method (MEM). The Nakanishi weight function as well as the corresponding light-front parton distribution amplitude (PDA) can be well determined. We confirm prior work on PDA computations, which was based on different methods.

Height probabilities in the Abelian sandpile model on the generalized finite Bethe lattice

Science.gov (United States)

Chen, Haiyan; Zhang, Fuji

2013-08-01

In this paper, we study the sandpile model on the generalized finite Bethe lattice with a particular boundary condition. Using a combinatorial method, we give the exact expressions for all single-site probabilities and some two-site joint probabilities. As a by-product, we prove that the height probabilities of bulk vertices are all the same for the Bethe lattice with certain given boundary condition, which was found from numerical evidence by Grassberger and Manna ["Some more sandpiles," J. Phys. (France) 51, 1077-1098 (1990)], 10.1051/jphys:0199000510110107700 but without a proof.

Mixed spin-((1)/(2)) and spin-1 Blume-Capel Ising ferrimagnetic system on the Bethe lattice

International Nuclear Information System (INIS)

Albayrak, Erhan; Keskin, Mustafa

2003-01-01

The mixed spin-((1)/(2)) and spin-1 Blume-Capel Ising ferrimagnetic system is studied on the Bethe lattice by using the exact recursion equations. Exact expressions for the magnetization, the quadrupolar moment, the Curie temperature and the free energy are found and the phase diagrams are constructed on the Bethe lattice with the coordination numbers q=3, 4, 5 and 6. The existence of a tricritical point is investigated for different values of q. The results are compared with those of other approximate methods and with the exact result on the Bethe lattice by using a discrete nonlinear map and also the exact results that are available for the case of the honeycomb lattice

Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

Science.gov (United States)

Semeriyanov, F.; Saphiannikova, M.; Heinrich, G.

2009-11-01

Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

International Nuclear Information System (INIS)

Semeriyanov, F; Saphiannikova, M; Heinrich, G

2009-01-01

Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

Quantum graphs with the Bethe-Sommerfeld property

Czech Academy of Sciences Publication Activity Database

Exner, Pavel; Turek, Ondřej

2017-01-01

Roč. 8, č. 3 (2017), s. 305-309 ISSN 2220-8054 R&D Projects: GA ČR GA17-01706S Institutional support: RVO:61389005 Keywords : periodic quantum graphs * gap number * delta-coupling * rectangular lattice graph * scale-invariant coupling * Bethe-Sommerfeld conjecture * golden mean Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics ( physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

The connection of two-particle relativistic quantum mechanics with the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Sazdjian, H.

1986-02-01

We show the formal equivalence between the wave equations of two-particle relativistic quantum mechanics, based on the manifestly covariant hamiltonian formalism with constraints, and the Bethe-Salpeter equation. This is achieved by algebraically transforming the latter so as to separate it into two independent equations which match the equations of hamiltonian relativistic quantum mechanics. The first equation determines the relative time evolution of the system, while the second one yields a three-dimensional eigenvalue equation. A connection is thus established between the Bethe-Salpeter wave function and its kernel on the one hand and the quantum mechanical wave function and interaction potential on the other. For the sector of solutions of the Bethe-Salpeter equation having non-relativistic limits, this relationship can be evaluated in perturbation theory. We also device a generalized form of the instantaneous approximation which simplifies the various expressions involved in the above relations. It also permits the evaluation of the normalization condition of the quantum mechanical wave function as a three-dimensional integral

The spin-3/2 Blume-Capel model on the Bethe lattice using the recursion method

International Nuclear Information System (INIS)

Albayrak, Erhan; Keskin, Mustafa

2000-01-01

The spin-3/2 Blume-Capel model is solved on the Bethe lattice using the exact recursion equations. The nature of the variation of the Curie temperature with the ratio of the single-ion anisotropy term to the exchange-coupling constant is studied and the phase diagrams are constructed on the Bethe lattice with the co-ordination numbers q=3 and 6. A comparison is made with the results of the other approximation schemes

The spin-3/2 Blume-Capel model on the Bethe lattice using the recursion method

CERN Document Server

Albayrak, E

2000-01-01

The spin-3/2 Blume-Capel model is solved on the Bethe lattice using the exact recursion equations. The nature of the variation of the Curie temperature with the ratio of the single-ion anisotropy term to the exchange-coupling constant is studied and the phase diagrams are constructed on the Bethe lattice with the co-ordination numbers q=3 and 6. A comparison is made with the results of the other approximation schemes.

Pessoa em Bethânia: os versos do desassossego na voz do encantamento

OpenAIRE

Barros, Andre Luiz Calsone

2013-01-01

Pessoa em Bethânia tem por tema a recriação dos versos de Caeiro no espetáculo Rosa dos Ventos O Show Encantado, tendo por intérprete Maria Bethânia. O corpus é o Poema VIII de Alberto Caeiro, heterônimo de Fernando Pessoa, da obra O Guardador de Rebanhos (1911 1912), transformado em roteiro dramáticomusical e tornado performance no espetáculo Rosa dos Ventos. Reinterpretado por meio da voz, do corpo, da música e dos mais variados recursos cênicos, o poema de Fernando ...

Bethe-Salpeter analysis of the radiative pion disintegration

Energy Technology Data Exchange (ETDEWEB)

Abad, J.; Pacheco, A.F. (Zaragoza Univ. (Spain). Dept. de Fisica Teorica); Rodriguez-Trias, R.; Esteve, J.G. (Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies)

1990-04-01

The structure-dependent amplitude of the decay {pi}{yields}e{nu}{gamma} is evaluated in the framework of a Bethe-Salpeter description for the pion. We assume a general B-S wave function in the S-wave. Within this hypothesis, we show that the gauge invariance constrains the different contributions of the wave functions to the amplitude, resulting in the vanishing of the axial form factor. (orig.).

Carl Friedrich von Weizsaecker - a physicist and philosopher in the shade of the nuclear bomb. A conversation on nuclear weapons and the responsibility of nuclear scientists

International Nuclear Information System (INIS)

Schaaf, M.

1996-06-01

The 50th anniversary of the first nuclear explosion (16th July 1945) prompted the editor of this collection to look again at the part played by German physicists in the nuclear weapons issue. Carl Friedrich von Weizsaecker, one of the last surviving witnesses of this period, kindly agreed to give a comprehensive interview on the German nuclear programme and the responsibility of physicists. The interview is published here for the first time and forms the central part of this brochure. It is complemented by two statements by Edward Teller and two historical letters. The author, in preparing this compilation, had in mind to contribute towards science-historical discussion and to give younger colleagues a graphic idea of the conflict surrounding nuclear research. (orig.) [de

Solution to Bethe-Salpeter equation via Mellin-Barnes transform

International Nuclear Information System (INIS)

Allendes, Pedro; Kniehl, Bernd; Kondrashuk, Igor; Rojas Medar, Marko; Notte Cuello, Eduardo A.

2012-06-01

We consider Mellin-Barnes transform of triangle ladder-like scalar diagram in d=4 dimensions. It is shown how multi-fold MB transform of the momentum integral corresponding to any number of rungs is reduced to two-fold MB transform. For this purpose we use Belokurov-Usyukina reduction method for four-dimensional scalar integrals in the position space. The result is represented in terms of Euler ψ-function and its derivatives. We derive new formulas for MB two-fold integration in the complex planes of two complex variables. We demonstrate that these formulas solve Bethe-Salpeter equation. We comment on further applications of solution to Bethe-Salpeter equation for vertices in N=4 supersymmetric Yang-Mills theory. We show that the recursive property of MB transforms observed in the present work for that kind of diagrams has nothing to do with quantum field theory, theory of integral transforms, or with theory of polylogarithms in general, but has an origin in a simple recursive property for smooth functions which can be shown by using basic methods of mathematical analysis.

Solution to Bethe-Salpeter equation via Mellin-Barnes transform

Energy Technology Data Exchange (ETDEWEB)

Allendes, Pedro [Concepcion Univ. (Chile). Dept. de Fisica; Kniehl, Bernd [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kondrashuk, Igor; Rojas Medar, Marko [Univ. del Bio-Bio, Chillan (Chile). Dept. de Ciencias Basicas; Notte Cuello, Eduardo A. [Univ. de La Serena (Chile). Facultad de Ciencias

2012-06-15

We consider Mellin-Barnes transform of triangle ladder-like scalar diagram in d=4 dimensions. It is shown how multi-fold MB transform of the momentum integral corresponding to any number of rungs is reduced to two-fold MB transform. For this purpose we use Belokurov-Usyukina reduction method for four-dimensional scalar integrals in the position space. The result is represented in terms of Euler {psi}-function and its derivatives. We derive new formulas for MB two-fold integration in the complex planes of two complex variables. We demonstrate that these formulas solve Bethe-Salpeter equation. We comment on further applications of solution to Bethe-Salpeter equation for vertices in N=4 supersymmetric Yang-Mills theory. We show that the recursive property of MB transforms observed in the present work for that kind of diagrams has nothing to do with quantum field theory, theory of integral transforms, or with theory of polylogarithms in general, but has an origin in a simple recursive property for smooth functions which can be shown by using basic methods of mathematical analysis.

Bethe ansatz for two-magnon scattering states in 2D and 3D Heisenberg–Ising ferromagnets

Science.gov (United States)

Bibikov, P. N.

2018-04-01

Two different versions of Bethe ansatz are suggested for evaluation of scattering two-magnon states in 2D and 3D Heisenberg–Ising ferromagnets on square and simple cubic lattices. It is shown that the two-magnon sector is subdivided on two subsectors related to non-interacting and scattering magnons. The former subsector possess an integrable regular dynamics and may be described by a natural modification of the usual Bethe Ansatz. The latter one is characterized by a non-integrable chaotic dynamics and may be treated only within discrete degenerative version of Bethe Ansatz previously suggested by the author. Some of these results are generalized for multi-magnon states of the Heisenberg–Ising ferromagnet on a D dimensional hyper cubic lattice. Dedicated to the memory of L D Faddeev.

Covariant Bethe-Salpeter wave functions for heavy hadrons

International Nuclear Information System (INIS)

Hussain, F.

1992-09-01

In recent years the dynamics of heavy mesons and baryons has considerably simplified by the development of the so-called heavy quark effective theory (HQET). A covariant formulation of heavy meson and heavy baryon decays in the leading order of the HQET is presented. The method is based on a Bethe-Salpeter formulation in the limit of the heavy quark mass going to infinity. 15 refs, 4 figs

Long-range psu(2,2|4) Bethe ansatze for gauge theory and strings

International Nuclear Information System (INIS)

Beisert, Niklas; Staudacher, Matthias

2005-01-01

We generalize various existing higher-loop Bethe ansatze for simple sectors of the integrable long-range dynamic spin chain describing planar N=4 super-Yang-Mills theory to the full psu(2,2|4) symmetry and, asymptotically, to arbitrary loop order. We perform a large number of tests of our conjectured equations, such as internal consistency, comparison to direct three-loop diagonalization and expected thermodynamic behavior. In the special case of the su(1|2) subsector, corresponding to a long-range t-J model, we are able to derive, up to three loops, the S-matrix and the associated nested Bethe ansatz from the gauge theory dilatation operator. We conjecture novel all-order S-matrices for the su(1|2) and su(1,1|2) subsectors, and show that they satisfy the Yang-Baxter equation. Throughout the paper, we muse about the idea that quantum string theory on AdS 5 xS 5 is also described by a psu(2,2|4) spin chain. We propose asymptotic all-order Bethe equations for this putative ''string chain'', which differ in a systematic fashion from the gauge theory equations

Periodic quantum graphs from the Bethe-Sommerfeld perspective

Czech Academy of Sciences Publication Activity Database

Exner, Pavel; Turek, Ondřej

2017-01-01

Roč. 50, č. 45 (2017), č. článku 455201. ISSN 1751-8113 R&D Projects: GA ČR GA17-01706S Institutional support: RVO:61389005 Keywords : quantum graphs * Bethe-Sommerfeld conjecture * vertex coupling * Diophantine approximation * periodic structure Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics ( physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 1.857, year: 2016

Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

Energy Technology Data Exchange (ETDEWEB)

Semeriyanov, F; Saphiannikova, M; Heinrich, G [Leibniz Institute of Polymer Research Dresden, Hohe str. 6, 01069 Dresden (Germany)], E-mail: fsemeriyanov@yahoo.de

2009-11-20

Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

The q-deformed analogue of the Onsager algebra: Beyond the Bethe ansatz approach

International Nuclear Information System (INIS)

Baseilhac, Pascal

2006-01-01

The spectral properties of operators formed from generators of the q-Onsager non-Abelian infinite-dimensional algebra are investigated. Using a suitable functional representation, all eigenfunctions are shown to obey a second-order q-difference equation (or its degenerate discrete version). In the algebraic sector associated with polynomial eigenfunctions (or their discrete analogues), Bethe equations naturally appear. Beyond this sector, where the Bethe ansatz approach is not applicable in related massive quantum integrable models, the eigenfunctions are also described. The spin-half XXZ open spin chain with general integrable boundary conditions is reconsidered in light of this approach: all the eigenstates are constructed. In the algebraic sector which corresponds to special relations among the parameters, known results are recovered

Numerical studies of the Bethe-Salpeter equation for a two-fermion bound state

Science.gov (United States)

de Paula, W.; Frederico, T.; Salmè, G.; Viviani, M.

2018-03-01

Some recent advances on the solution of the Bethe-Salpeter equation (BSE) for a two-fermion bound system directly in Minkowski space are presented. The calculations are based on the expression of the Bethe-Salpeter amplitude in terms of the so-called Nakanishi integral representation and on the light-front projection (i.e. the integration of the light-front variable k - = k 0 - k 3). The latter technique allows for the analytically exact treatment of the singularities plaguing the two-fermion BSE in Minkowski space. The good agreement observed between our results and those obtained using other existing numerical methods, based on both Minkowski and Euclidean space techniques, fully corroborate our analytical treatment.

Electronic structure of disordered binary alloys with short range correlation in Bethe lattice

International Nuclear Information System (INIS)

Moreno, I.F.

1987-01-01

The determination of the electronic structure of a disordered material along the tight-binding model when applied to a Bethe lattice. The diagonal as well as off-diagonal disorder, are considered. The coordination number on the Bethe is fixed lattice to four (Z=4) that occurs in most compound semiconductors. The main proposal was to study the conditions under which a relatively simple model of a disordered material, i.e, a binary alloy, could account for the basic properties of transport or more specifically for the electronic states in such systems. By using a parametrization of the pair probability the behaviour of the electronic density of states (DOS) for different values of the short range order parameter, σ, which makes possible to treat the segregated, random and alternating cases, was analysed. In solving the problem via the Green function technique in the Wannier representation a linear chain of atoms was considered and using the solution of such a 1-D system the problem of the Bethe lattice which is constructed using such renormalized chains as elements, was solved. The results indicate that the obtained DOS are strongly dependent on the correlation assumed for the occupancy in the lattice. (author) [pt

The Beer/Bethe/Uexküll paper (1899) and misinterpretations surrounding 'vitalistic behaviorism'.

Science.gov (United States)

Mildenberger, Florian

2006-01-01

In the history of behaviorism the paper of the three physiologists Theodor Beer, Albrecht Bethe and Jakob von Uexküll from 1899 plays an important role. Many researchers were influenced by this paper and identified it as fundamental for objective psychological research. But during the period of its adoption (1900-1925) psychologists did not notice that Beer, Bethe and Uexküll had distanced themselves from their own paper, because it had been ignored in physiological and biological discussions. Moreover, one of the three (Beer) had to resign from the scientific community because of private scandal and another one (Uexküll) changed all of his views and left the base of objective science for subjective vitalism. However, this did not change his adoption of behaviorism.

Bethe Ansatz and exact form factors of the O(N) Gross Neveu-model

International Nuclear Information System (INIS)

Babujian, Hrachya M.; Foerster, Angela; Karowski, Michael

2016-01-01

We apply previous results on the O(N) Bethe Ansatz http://dx.doi.org/10.1088/1751-8113/45/5/055207, http://arxiv.org/abs/1204.3479, http://dx.doi.org/10.1007/JHEP11(2013)089 to construct a general form factor formula for the O(N) Gross-Neveu model. We examine this formula for several operators, such as the energy momentum, the spin-field and the current. We also compare these results with the 1/N expansion of this model and obtain full agreement. We discuss bound state form factors, in particular for the three particle form factor of the field. In addition for the two particle case we prove a recursion relation for the K-functions of the higher level Bethe Ansatz.

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-02-01

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

Distinct solutions of infinite U Hubbard model through nested Bethe ansatz and Gutzwiller projection operator approach

International Nuclear Information System (INIS)

Mishra, A.K.; Kishore, R.

2009-01-01

The exact nested Bethe ansatz solution for the one dimensional (1-D) U infinity Hubbard model show that the state vectors are a product of spin-less fermion and spin wavefunctions, or an appropriate superposition of such factorized wavefunctions. The spin-less fermion component of the wavefunctions ensures no double occupancy at any site. It had been demonstrated that the nested Bethe ansatz wavefunctions in the U infinity limit obey orthofermi statistics. Gutzwiller projection operator formalism is the another well known technique employed to handle U infinity Hubbard model. In general, this approach does not lead to spin-less fermion wavefunctions. Therefore, the nested Bethe ansatz and Gutzwiller projection operator approach give rise to different kinds of the wavefunctions for the U infinity limit of 1-D Hubbard Hamiltonian. To compare the consequences of this dissimilarity in the wavefunctions, we have obtained the ground state energy of a finite system consisting of three particles on a four site closed chain. It is shown that in the nested Bethe ansatz implemented through orthofermion algebra, all the permissible 2 3 spin configurations are degenerate in the ground state. This eight fold degeneracy of the ground state is absent in the Gutzwiller projection operator approach. This finding becomes relevant in the context of known exact U infinity results, which require that all the energy levels are 2 N -fold degenerate for an N particle system.

Heavy quark effective theory, interpolating fields and Bethe-Salpeter amplitudes

International Nuclear Information System (INIS)

Hussain, F.; Thomspon, G.

1994-07-01

We use the LSZ reduction theorem and interpolating fields, along with the heavy quark effective theory, to investigate the structure of the Bethe-Salpeter amplitude for heavy hadrons. We show how a simple form of this amplitude, used extensively in heavy hadron decay calculations, follows naturally up to O(1/M) from these field theoretic considerations. (author). 13 refs, 1 tab

O(N)-matrix difference equations and a nested Bethe ansatz

International Nuclear Information System (INIS)

Babujian, Hrachya M; Foerster, Angela; Karowski, Michael

2012-01-01

A system of O(N)-matrix difference equations is solved by means of the off-shell version of the nested algebraic Bethe ansatz. In the nesting process, a new object, the Π-matrix, is introduced to overcome the complexities of the O(N)-group structure. The highest weight property of the solutions is proved and some explicit examples are discussed. (paper)

Lepton-pair production of a light pseudoscalar particle via the Bethe-Heitler process

International Nuclear Information System (INIS)

Kim, B.R.; Stamm, C.

1983-01-01

Bethe-Heitler processes of light pseudoscalar particles off nuclei are at present very important experimentally. For these processes we present our results which seem to differ from previous theoretical calculations found in the literature. (orig.)

Range-separated time-dependent density-functional theory with a frequency-dependent second-order Bethe-Salpeter correlation kernel

Energy Technology Data Exchange (ETDEWEB)

Rebolini, Elisa, E-mail: elisa.rebolini@kjemi.uio.no; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr [Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ Paris 06, CNRS, 4 place Jussieu, F-75005 Paris (France)

2016-03-07

We present a range-separated linear-response time-dependent density-functional theory (TDDFT) which combines a density-functional approximation for the short-range response kernel and a frequency-dependent second-order Bethe-Salpeter approximation for the long-range response kernel. This approach goes beyond the adiabatic approximation usually used in linear-response TDDFT and aims at improving the accuracy of calculations of electronic excitation energies of molecular systems. A detailed derivation of the frequency-dependent second-order Bethe-Salpeter correlation kernel is given using many-body Green-function theory. Preliminary tests of this range-separated TDDFT method are presented for the calculation of excitation energies of the He and Be atoms and small molecules (H{sub 2}, N{sub 2}, CO{sub 2}, H{sub 2}CO, and C{sub 2}H{sub 4}). The results suggest that the addition of the long-range second-order Bethe-Salpeter correlation kernel overall slightly improves the excitation energies.

Physics over easy Breakfasts with Beth and physics

CERN Document Server

Azaroff, L V

2010-01-01

During a sequence of meals, the author relates the principal features of physics in easy-to-understand conversations with his wife Beth. Beginning with the studies of motion by Galileo and Newton through to the revolutionary theories of relativity and quantum mechanics in the 20th century, all important aspects of electricity, energy, magnetism, gravity and the structure of matter and atoms are explained and illustrated. The second edition similarly recounts the more recent application of these theories to nanoparticles, Bose-Einstein condensates, quantum entanglement and quantum computers. By

Covariant solutions of the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Williams, A.G.; Kusaka, K.; Simpson, K.M.

1997-01-01

There is a need for covariant solutions of bound state equations in order to construct realistic QCD based models of mesons and baryons. Furthermore, we ideally need to know the structure of these bound states in all kinematical regimes, which makes a direct solution in Minkowski space (without any 3-dimensional reductions) desirable. The Bethe-Salpeter equation (BSE) for bound states in scalar theories is reformulated and solved for arbitrary scattering kernels in terms of a generalized spectral representation directly in Minkowski space. This differs from the conventional Euclidean approach, where the BSE can only be solved in ladder approximation after a Wick rotation. (author)

Construction of Bethe Salpeter wave functions and applications in QCD

International Nuclear Information System (INIS)

Gromes, D.

1993-01-01

We suggest an ansatz for the Bethe Salpeter wave function which is strictly covariant, obeys the spectrum conditions, and has the correct non relativistic limit. As a first simple application we present a wave function for the pion. It contains two parameters, one of them being the quark mass. The decay constant and the form factor derived from this are in excellent agreement with the data. (orig.)

Stochastic integration of the Bethe-Salpeter equation for two bound fermions

International Nuclear Information System (INIS)

Salomon, M.

1988-09-01

A non-perturbative method using a Monte Carlo algorithm is used to integrate the Bethe-Salpeter equation in momentum space. Solutions for two scalars and two fermions with an arbitrary coupling constant are calculated for bound states in the ladder approximation. The results are compared with other numerical methods. (Author) (13 refs., 2 figs.)

A separable approximation of the NN-Paris-potential in the framework of the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Schwarz, K.; Haidenbauer, J.; Froehlich, J.

1985-09-01

The Bethe-Salpeter equation is solved with a separable kernel for the most important nucleon-nucleon partial wave states. We employ the Ernst Shakin-Thaler method in the framework of minimal relativity (Blankenbeckler-Sugar equation) to generate a separable representation of the meson-theoretical Paris potential. These separable interactions, which closely approximate the on-shell- and half-off-shell behaviour of the Paris potential, are then cast into a covariant form for application in the Bethe-Salpeter equation. The role of relativistic effects is discussed with respect to on-shell and off-shell properties of the NN-system. (Author)

Accuracy of the Bethe approximation for hyperparameter estimation in probabilistic image processing

International Nuclear Information System (INIS)

Tanaka, Kazuyuki; Shouno, Hayaru; Okada, Masato; Titterington, D M

2004-01-01

We investigate the accuracy of statistical-mechanical approximations for the estimation of hyperparameters from observable data in probabilistic image processing, which is based on Bayesian statistics and maximum likelihood estimation. Hyperparameters in statistical science correspond to interactions or external fields in the statistical-mechanics context. In this paper, hyperparameters in the probabilistic model are determined so as to maximize a marginal likelihood. A practical algorithm is described for grey-level image restoration based on a Gaussian graphical model and the Bethe approximation. The algorithm corresponds to loopy belief propagation in artificial intelligence. We examine the accuracy of hyperparameter estimation when we use the Bethe approximation. It is well known that a practical algorithm for probabilistic image processing can be prescribed analytically when a Gaussian graphical model is adopted as a prior probabilistic model in Bayes' formula. We are therefore able to compare, in a numerical study, results obtained through mean-field-type approximations with those based on exact calculation

Semi-classical analysis of the inner product of Bethe states

International Nuclear Information System (INIS)

Bettelheim, Eldad; Kostov, Ivan

2014-01-01

We study the inner product of two Bethe states, one of which is taken on-shell, in an inhomogeneous XXX chain in the Sutherland limit, where the number of magnons is comparable with the length L of the chain and the magnon rapidities arrange in a small number of macroscopically large Bethe strings. The leading order in the large L limit is known to be expressed through a contour integral of a dilogarithm. Here we derive the sub-leading term. Our analysis is based on a new contour-integral representation of the inner product in terms of a Fredholm determinant. We give two derivations of the sub-leading term. Besides a direct derivation by solving a Riemann–Hilbert problem, we give a less rigorous, but more intuitive derivation by field-theoretical methods. For that we represent the Fredholm determinant as an expectation value in a Fock space of chiral fermions and then bosonize. We construct a collective field for the bosonized theory, the short wave-length part of which may be evaluated exactly, while the long wave-length part is amenable to a 1/L expansion. Our treatment thus results in a systematic 1/L expansion of structure factors within the Sutherland limit. (paper)

Deep inelastic scattering on the deuteron in the Bethe-Salpeter formalism

International Nuclear Information System (INIS)

Kaptari, L.P.; Kazakov, K.Yu.; Umnikov, A.Yu.; Khanna, F.C.

1996-01-01

The nuclear effects in the spin structure functions of the deuteron g 1 and b 2 are estimated in a fully covariant approach of the Bethe-Salpeter formalism. The construction of the relativistic wave function of the deuteron is discussed in detail. Numerical results for g 1 and b 2 are compared with nonrelativistic results and relativistic corrections are discussed [ru

Solution of the Bethe-Salpeter equation in the field of a plane electromagnetic wave

International Nuclear Information System (INIS)

Starostin, V.S.

1988-01-01

A solution is obtained of the Bethe--Salpeter equation for positronium in the field of linearly and circularly polarized plane electromagnetic waves at frequencies much higher than atomic. It is not assumed that the field is weak

Covariant solutions of the Bethe-Salpeter equation and an application to the nucleon structure function

International Nuclear Information System (INIS)

Williams, A.G.

1998-01-01

There is a need for covariant solutions of bound state equations in order to construct realistic QCD based models of mesons and baryons. Furthermore, we ideally need to know the structure of these bound states in all kinematical regimes, which makes a direct solution in Minkowski space (without any 3-dimensional reductions) desirable. The Bethe-Salpeter equation (BSE) for bound states in scalar theories is reformulated and solved for arbitrary scattering kernels in terms of a generalized spectral representation directly in Minkowski space. This differs from the conventional Euclidean approach, where the BSE can only be solved in ladder approximation after a Wick rotation. An application of covariant Bethe-Salpeter solutions to a quark-diquark model of the nucleon is also briefly discussed. (orig.)

Algebraic Bethe ansatz for the quantum group invariant open XXZ chain at roots of unity

Directory of Open Access Journals (Sweden)

Azat M. Gainutdinov

2016-08-01

Full Text Available For generic values of q, all the eigenvectors of the transfer matrix of the Uqsl(2-invariant open spin-1/2 XXZ chain with finite length N can be constructed using the algebraic Bethe ansatz (ABA formalism of Sklyanin. However, when q is a root of unity (q=eiπ/p with integer p≥2, the Bethe equations acquire continuous solutions, and the transfer matrix develops Jordan cells. Hence, there appear eigenvectors of two new types: eigenvectors corresponding to continuous solutions (exact complete p-strings, and generalized eigenvectors. We propose general ABA constructions for these two new types of eigenvectors. We present many explicit examples, and we construct complete sets of (generalized eigenvectors for various values of p and N.

Clinical trials of boron neutron capture therapy [in humans] [at Beth Israel Deaconess Medical Center][at Brookhaven National Laboratory

International Nuclear Information System (INIS)

Wallace, Christine

2001-01-01

Assessment of research records of Boron Neutron Capture Therapy was conducted at Brookhaven National Laboratory and Beth Israel Deaconess Medical Center using the Code of Federal Regulations, FDA Regulations and Good Clinical Practice Guidelines. Clinical data were collected FR-om subjects' research charts, and differences in conduct of studies at both centers were examined. Records maintained at Brookhaven National Laboratory were not in compliance with regulatory standards. Beth Israel's records followed federal regulations. Deficiencies discovered at both sites are discussed in the reports

Low-temperature excitations within the Bethe approximation

International Nuclear Information System (INIS)

Biazzo, I; Ramezanpour, A

2013-01-01

We propose the variational quantum cavity method to construct a minimal energy subspace of wavevectors that are used to obtain some upper bounds for the energy cost of the low-temperature excitations. Given a trial wavefunction we use the cavity method of statistical physics to estimate the Hamiltonian expectation and to find the optimal variational parameters in the subspace of wavevectors orthogonal to the lower-energy wavefunctions. To this end, we write the overlap between two wavefunctions within the Bethe approximation, which allows us to replace the global orthogonality constraint with some local constraints on the variational parameters. The method is applied to the transverse Ising model and different levels of approximations are compared with the exact numerical solutions for small systems. (paper)

Bethe ansatz study for ground state of Fateev Zamolodchikov model

International Nuclear Information System (INIS)

Ray, S.

1997-01-01

A Bethe ansatz study of a self-dual Z N spin lattice model, originally proposed by V. A. Fateev and A. B. Zamolodchikov, is undertaken. The connection of this model to the Chiral Potts model is established. Transcendental equations connecting the zeros of Fateev endash Zamolodchikov transfer matrix are derived. The free energies for the ferromagnetic and the anti-ferromagnetic ground states are found for both even and odd spins. copyright 1997 American Institute of Physics

From tricritical Ising to critical Ising by thermodynamic Bethe ansatz

International Nuclear Information System (INIS)

Zamolodchikov, A.B.

1991-01-01

A simple factorized scattering theory is suggested for the massless Goldstone fermions of the trajectory flowing from the tricritical Ising fixed point to the critical Ising one. The thermodynamic Bethe ansatz approach is applied to this scattering theory to support its interpretation both analytically and numerically. As a generalization a sequence of massless TBA systems is proposed which seems relevant for the trajectories interpolating between two successive minimal CFT models M p and M p-1 . (orig.)

Experimental observation of Bethe strings

Science.gov (United States)

Wang, Zhe; Wu, Jianda; Yang, Wang; Bera, Anup Kumar; Kamenskyi, Dmytro; Islam, A. T. M. Nazmul; Xu, Shenglong; Law, Joseph Matthew; Lake, Bella; Wu, Congjun; Loidl, Alois

2018-02-01

Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg-Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced quantum-critical regime, we identify strings and fractional magnetic excitations that are accurately described by the Bethe ansatz. Close to quantum criticality, the string excitations govern the quantum spin dynamics, whereas the fractional excitations, which are dominant at low energies, reflect the antiferromagnetic quantum fluctuations. Today, Bethe’s result is important not only in the field of quantum magnetism but also more broadly, including in the study of cold atoms and in string theory; hence, we anticipate that our work will shed light on the study of complex many-body systems in general.

Correlation functions of the spin chains. Algebraic Bethe Ansatz approach

International Nuclear Information System (INIS)

Kitanine, N.

2007-09-01

Spin chains are the basic elements of integrable quantum models. These models have direct applications in condense matter theory, in statistical physics, in quantum optics, in field theory and even in string theory but they are also important because they enable us to solve, in an exact manner, non-perturbative phenomena that otherwise would stay unresolved. The method described in this work is based on the algebraic Bethe Ansatz. It is shown how this method can be used for the computation of null temperature correlation functions of the Heisenberg 1/2 spin chain. The important point of this approach is the solution of the inverse quantum problem given by the XXZ spin chain. This solution as well as a simple formulae for the scalar product of the Bethe states, have enabled us to get the most basic correlation functions under the form of multiple integrals. The formalism of multiple integrals open the way for asymptotic analysis for a few physical quantities like the probability of vacuum formation. It is worth noticing that this formalism can give exact results for two-point functions that are the most important correlation functions for applications. A relationship has been discovered between these multiple integrals and the sum of the form factors. The results have been extended to dynamical correlation functions. (A.C.)

Comment on the analysis of Bethe-Salpeter scattering states by Hormozdiari and Huang

International Nuclear Information System (INIS)

Tryon, E.P.

1978-01-01

The analysis of Bethe-Salpeter scattering states by Hormozdiari and Huang appears to contain invalid mathematical arguments. When these arguments are rectified, one arrives at substantially different conclusions. In particular, the prescription of Hormozdiari and Huang for constructing such states does not seem applicable to any process occurring in nature

Correlation functions of the spin chains. Algebraic Bethe Ansatz approach; Fonctions de correlation des chaines de spin. Approche de l'ansatz de Bethe algebrique

Energy Technology Data Exchange (ETDEWEB)

Kitanine, N

2007-09-15

Spin chains are the basic elements of integrable quantum models. These models have direct applications in condense matter theory, in statistical physics, in quantum optics, in field theory and even in string theory but they are also important because they enable us to solve, in an exact manner, non-perturbative phenomena that otherwise would stay unresolved. The method described in this work is based on the algebraic Bethe Ansatz. It is shown how this method can be used for the computation of null temperature correlation functions of the Heisenberg 1/2 spin chain. The important point of this approach is the solution of the inverse quantum problem given by the XXZ spin chain. This solution as well as a simple formulae for the scalar product of the Bethe states, have enabled us to get the most basic correlation functions under the form of multiple integrals. The formalism of multiple integrals open the way for asymptotic analysis for a few physical quantities like the probability of vacuum formation. It is worth noticing that this formalism can give exact results for two-point functions that are the most important correlation functions for applications. A relationship has been discovered between these multiple integrals and the sum of the form factors. The results have been extended to dynamical correlation functions. (A.C.)

The 14N(p, γ)15O reaction studied at low and high beam energy

International Nuclear Information System (INIS)

Marta, Michele

2012-01-01

The Bethe-Weizsaecker cycle consists of a set of nuclear reactions that convert hydrogen into helium and release energy in the stars. It determines the luminosity of low-metal stars at their turn-off from the main-sequence in the Hertzsprung-Russel diagram, so its rate enters the calculation of the globular clusters' age, an independent lower limit on the age of the universe. The cycle contributes less than 1% to our Sun's luminosity, but it produces neutrinos that can in principle be measured on Earth in underground experiments and bring direct information of the physical conditions in the solar core, provided that the nuclear reaction rate is known with sufficient precision. The 14 N(p,γ) 15 O reaction is the slowest reaction of the Bethe-Weizsaecker cycle and establishes its rate. Its cross section is the sum of the contributions by capture to different excited levels and to the ground state in 15 O. Recent experiments studied the region of the resonance at E p = 278 keV. Only one modern data set from an experiment performed in 1987 is available for the high-energy domain. Both energy ranges are needed to constrain the fit of the excitation function in the R-matrix framework and to obtain a reliable extrapolated S-factor at the very low astrophysical energies. The present research work studied the 14 N(p,γ) 15 O reaction in the LUNA (Laboratory for Underground Nuclear Astrophysics) underground facility at three proton energies 0.36, 0.38, 0.40MeV, and in Dresden in the energy range E p = 0.6 - 2MeV. In both cases, an intense proton beam was sent on solid titanium nitride sputtered targets, and the prompt photons emitted from the reaction were detected with germanium detectors. At LUNA, a composite germanium detector was used. This enabled a measurement with dramatically reduced summing corrections with respect to previous studies. The cross sections for capture to the ground state and to the excited states at 5181, 6172, and 6792 keV in 15 O have been

The {sup 14}N(p, {gamma}){sup 15}O reaction studied at low and high beam energy

Energy Technology Data Exchange (ETDEWEB)

Marta, Michele

2012-07-01

The Bethe-Weizsaecker cycle consists of a set of nuclear reactions that convert hydrogen into helium and release energy in the stars. It determines the luminosity of low-metal stars at their turn-off from the main-sequence in the Hertzsprung-Russel diagram, so its rate enters the calculation of the globular clusters' age, an independent lower limit on the age of the universe. The cycle contributes less than 1% to our Sun's luminosity, but it produces neutrinos that can in principle be measured on Earth in underground experiments and bring direct information of the physical conditions in the solar core, provided that the nuclear reaction rate is known with sufficient precision. The {sup 14}N(p,{gamma}){sup 15}O reaction is the slowest reaction of the Bethe-Weizsaecker cycle and establishes its rate. Its cross section is the sum of the contributions by capture to different excited levels and to the ground state in {sup 15}O. Recent experiments studied the region of the resonance at E{sub p} = 278 keV. Only one modern data set from an experiment performed in 1987 is available for the high-energy domain. Both energy ranges are needed to constrain the fit of the excitation function in the R-matrix framework and to obtain a reliable extrapolated S-factor at the very low astrophysical energies. The present research work studied the {sup 14}N(p,{gamma}){sup 15}O reaction in the LUNA (Laboratory for Underground Nuclear Astrophysics) underground facility at three proton energies 0.36, 0.38, 0.40MeV, and in Dresden in the energy range E{sub p} = 0.6 - 2MeV. In both cases, an intense proton beam was sent on solid titanium nitride sputtered targets, and the prompt photons emitted from the reaction were detected with germanium detectors. At LUNA, a composite germanium detector was used. This enabled a measurement with dramatically reduced summing corrections with respect to previous studies. The cross sections for capture to the ground state and to the excited states

Anomalous magnetic nucleon moments in a Bethe-Salpeter model

International Nuclear Information System (INIS)

Chak Wing Chan.

1978-01-01

We investigate the anomalous magnetic moment of the nucleon in a field theoretic many-channel model for the electromagnetic form factors of the N anti N, the ππ, the K anti K, the πω and the πrho systems. Propagator self-energy corrections from the Ward idendity and phenomenological strong vertex corrections are both included. The photon is coupled minimally to pions, kaons and nucleons with power multiplicative renormalization. With solutions in the framework of the Bethe-Salpeter equation we obtain a value 1.84 for the isovector moment and a value -0.02 for the isoscalar moment. (orig.)

Thermodynamic Bethe Ansatz for the Spin-1/2 Staggered XXZ- Model

OpenAIRE

Mkhitaryan, V. V.; Sedrakyan, A. G.

2003-01-01

We develop the technique of Thermodynamic Bethe Ansatz to investigate the ground state and the spectrum in the thermodynamic limit of the staggered $XXZ$ models proposed recently as an example of integrable ladder model. This model appeared due to staggered inhomogeneity of the anisotropy parameter $\\Delta$ and the staggered shift of the spectral parameter. We give the structure of ground states and lowest lying excitations in two different phases which occur at zero temperature.

A political end to a pioneering career: Marianne Beth and the psychology of religion

NARCIS (Netherlands)

Belzen, J.A.

2011-01-01

Although forgotten in both Religionswissenschaft (the Science of Religion) and psychology, Marianne Beth (1880-1984), initially trained as a lawyer and already in 1928 called a "leading European woman", must be considered as one of the female pioneers of these fields. She has been active especially

On string solutions of Bethe equations in N=4 supersymmetric Yang-Mills theory

International Nuclear Information System (INIS)

Bytsko, A.G.; Shenderovich, I.E.

2007-12-01

The Bethe equations, arising in description of the spectrum of the dilatation operator for the su(2) sector of the N=4 supersymmetric Yang-Mills theory, are considered in the anti-ferromagnetic regime. These equations are deformation of those for the Heisenberg XXX magnet. It is proven that in the thermodynamic limit roots of the deformed equations group into strings. It is proven that the corresponding Yang's action is convex, which implies uniqueness of solution for centers of the strings. The state formed of strings of length (2n+1) is considered and the density of their distribution is found. It is shown that the energy of such a state decreases as n grows. It is observed that non-analyticity of the left hand side of the Bethe equations leads to an additional contribution to the density and energy of strings of even length. Whence it is concluded that the structure of the anti-ferromagnetic vacuum is determined by the behaviour of exponential corrections to string solutions in the thermodynamic limit and possibly involves strings of length 2. (orig.)

On string solutions of Bethe equations in N=4 supersymmetric Yang-Mills theory

Energy Technology Data Exchange (ETDEWEB)

Bytsko, A.G. [Rossijskaya Akademiya Nauk, St. Petersburg (Russian Federation). Inst. Matematiki]|[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Shenderovich, I.E. [St. Petersburg State Univ. (Russian Federation). Physics Dept.

2007-12-15

The Bethe equations, arising in description of the spectrum of the dilatation operator for the su(2) sector of the N=4 supersymmetric Yang-Mills theory, are considered in the anti-ferromagnetic regime. These equations are deformation of those for the Heisenberg XXX magnet. It is proven that in the thermodynamic limit roots of the deformed equations group into strings. It is proven that the corresponding Yang's action is convex, which implies uniqueness of solution for centers of the strings. The state formed of strings of length (2n+1) is considered and the density of their distribution is found. It is shown that the energy of such a state decreases as n grows. It is observed that non-analyticity of the left hand side of the Bethe equations leads to an additional contribution to the density and energy of strings of even length. Whence it is concluded that the structure of the anti-ferromagnetic vacuum is determined by the behaviour of exponential corrections to string solutions in the thermodynamic limit and possibly involves strings of length 2. (orig.)

Bethe ansatz equations for open spin chains from giant gravitons

International Nuclear Information System (INIS)

Nepomechie, Rafael I.

2009-01-01

We investigate the open spin chain describing the scalar sector of the Y = 0 giant graviton brane at weak coupling. We provide a direct proof of integrability in the SU(2) and SU(3) sectors by constructing the transfer matrices. We determine the eigenvalues of these transfer matrices in terms of roots of the corresponding Bethe ansatz equations (BAEs). Based on these results, we propose BAEs for the full SO(6) sector. We find that, in the weak-coupling limit, the recently-proposed all-loop BAEs essentially agree with those proposed in the present work.

Bethe Ansatz and supersymmetric vacua

International Nuclear Information System (INIS)

Nekrasov, Nikita; Shatashvili, Samson

2009-01-01

Supersymmetric vacua of two dimensional N = 4 gauge theories with matter, softly broken by the twisted masses down to N = 2, are shown to be in one-to-one correspondence with the eigenstates of integrable spin chain Hamiltonians. Examples include: the Heisenberg SU(2)XXX spin chain which is mapped to the two dimensional U(N) theory with fundamental hypermultiplets, the XXZ spin chain which is mapped to the analogous three dimensional super-Yang-Mills theory compactified on a circle, the XYZ spin chain and eight-vertex model which are related to the four dimensional theory compactified on T 2 . A consequence of our correspondence is the isomorphism of the quantum cohomology ring of various quiver varieties, such as cotangent bundles to (partial) flag varieties and the ring of quantum integrals of motion of various spin chains. The correspondence extends to any spin group, representations, boundary conditions, and inhomogeneity, it includes Sinh-Gordon and non-linear Schroedinger models as well as the dynamical spin chains like Hubbard model. Compactifications of four dimensional N = 2 theories on a two-sphere lead to the instanton-corrected Bethe equations.

Low-lying qq(qq)-bar states in a relativistic model based on the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Ram, B.; Kriss, V.

1985-01-01

Low-lying qq(qq)-bar states are analysed in a previously given relativistic model based on the Bethe-Salpeter equation. It is not got M-diquonia, P-mesonia, or meson molecules, but it is got T-diquonia

Comultiplication in ABCD algebra and scalar products of Bethe wave functions

International Nuclear Information System (INIS)

Mikhailov, A.

1995-01-01

The representation of scalar products of Bethe wave functions in terms of dual fields, plays an important role in the theory of completely integrable models. The proof is based on the explicit expression for the open-quotes seniorclose quotes coefficient, which was guessed in the Izergin paper and then proved to satisfy some recurrent relations, which determine it unambiguously. In this paper we present an alternative proof based on direct computation. It uses the operation of comultiplication in the ABCD-algebra

Algebraic Bethe ansatz for U(1) invariant integrable models: Compact and non-compact applications

International Nuclear Information System (INIS)

Martins, M.J.; Melo, C.S.

2009-01-01

We apply the algebraic Bethe ansatz developed in our previous paper [C.S. Melo, M.J. Martins, Nucl. Phys. B 806 (2009) 567] to three different families of U(1) integrable vertex models with arbitrary N bond states. These statistical mechanics systems are based on the higher spin representations of the quantum group U q [SU(2)] for both generic and non-generic values of q as well as on the non-compact discrete representation of the SL(2,R) algebra. We present for all these models the explicit expressions for both the on-shell and the off-shell properties associated to the respective transfer matrices eigenvalue problems. The amplitudes governing the vectors not parallel to the Bethe states are shown to factorize in terms of elementary building blocks functions. The results for the non-compact SL(2,R) model are argued to be derived from those obtained for the compact systems by taking suitable N→∞ limits. This permits us to study the properties of the non-compact SL(2,R) model starting from systems with finite degrees of freedom.

Algebraic Bethe ansatz for U(1) invariant integrable models: Compact and non-compact applications

Science.gov (United States)

Martins, M. J.; Melo, C. S.

2009-10-01

We apply the algebraic Bethe ansatz developed in our previous paper [C.S. Melo, M.J. Martins, Nucl. Phys. B 806 (2009) 567] to three different families of U(1) integrable vertex models with arbitrary N bond states. These statistical mechanics systems are based on the higher spin representations of the quantum group U[SU(2)] for both generic and non-generic values of q as well as on the non-compact discrete representation of the SL(2,R) algebra. We present for all these models the explicit expressions for both the on-shell and the off-shell properties associated to the respective transfer matrices eigenvalue problems. The amplitudes governing the vectors not parallel to the Bethe states are shown to factorize in terms of elementary building blocks functions. The results for the non-compact SL(2,R) model are argued to be derived from those obtained for the compact systems by taking suitable N→∞ limits. This permits us to study the properties of the non-compact SL(2,R) model starting from systems with finite degrees of freedom.

Integrability in three dimensions: Algebraic Bethe ansatz for anyonic models

Directory of Open Access Journals (Sweden)

Sh. Khachatryan

2015-10-01

Full Text Available We extend basic properties of two dimensional integrable models within the Algebraic Bethe Ansatz approach to 2+1 dimensions and formulate the sufficient conditions for the commutativity of transfer matrices of different spectral parameters, in analogy with Yang–Baxter or tetrahedron equations. The basic ingredient of our models is the R-matrix, which describes the scattering of a pair of particles over another pair of particles, the quark-anti-quark (meson scattering on another quark-anti-quark state. We show that the Kitaev model belongs to this class of models and its R-matrix fulfills well-defined equations for integrability.

Hospital CIO Explains Blockchain Potential: An Interview with Beth Israel Deaconess Medical Center's John Halamka.

Science.gov (United States)

Mertz, Leslie

2018-01-01

Work is already underway to bring blockchain technology to the healthcare industry, and hospital administrators are trying to figure out what it can do for them, their clinicians, and their patients. That includes administrators at Beth Israel Deaconess Medical Center, a leading academic medical center located in Boston.

A separable approach to the Bethe-Salpeter equation and its application to nucleon-nucleon scattering

International Nuclear Information System (INIS)

Schwarz, K.; Froehlich, J.; Zingl, H.F.K.

1980-01-01

The Bethe-Salpeter equation is solved in closed form with the help of a four dimensional separable 'potential'. For possible applications to three-nucleon investigations the authors have fitted all nucleon-nucleon S-wave phase shifts in a sufficient way by this method; in addition they also present an example for a P-wave. (Auth.)

A Bethe ansatz solvable model for superpositions of Cooper pairs and condensed molecular bosons

International Nuclear Information System (INIS)

Hibberd, K.E.; Dunning, C.; Links, J.

2006-01-01

We introduce a general Hamiltonian describing coherent superpositions of Cooper pairs and condensed molecular bosons. For particular choices of the coupling parameters, the model is integrable. One integrable manifold, as well as the Bethe ansatz solution, was found by Dukelsky et al. [J. Dukelsky, G.G. Dussel, C. Esebbag, S. Pittel, Phys. Rev. Lett. 93 (2004) 050403]. Here we show that there is a second integrable manifold, established using the boundary quantum inverse scattering method. In this manner we obtain the exact solution by means of the algebraic Bethe ansatz. In the case where the Cooper pair energies are degenerate we examine the relationship between the spectrum of these integrable Hamiltonians and the quasi-exactly solvable spectrum of particular Schrodinger operators. For the solution we derive here the potential of the Schrodinger operator is given in terms of hyperbolic functions. For the solution derived by Dukelsky et al., loc. cit. the potential is sextic and the wavefunctions obey PT-symmetric boundary conditions. This latter case provides a novel example of an integrable Hermitian Hamiltonian acting on a Fock space whose states map into a Hilbert space of PT-symmetric wavefunctions defined on a contour in the complex plane

Single-time reduction of bethe-salpeter formalism for two-fermion system

International Nuclear Information System (INIS)

Arkhipov, A.A.

1988-01-01

The single-time reduction method proposed in other refs. for the system of two scalar particles is generalized for the case of two-fermion system. A self-consistent procedure of single-time reduction has been constructed both in terms of the Bethe-Salpeter wave function and in terms of the Green's function of two-fermion system. Three-dimensional dynamic equations have been obtained for single-time wave functions and two-time Green's functions of a two-fermion system and the Schroedinger structure of the equations obtained is shown to be a consequence of the causality structure of the local QFT. 32 refs

Nested Bethe Ansatz for Spin Ladder Model with Open Boundary Conditions

International Nuclear Information System (INIS)

Wu Junfang; Zhang Chunmin; Yue Ruihong; Li Runling

2005-01-01

The nested Bethe ansatz (BA) method is applied to find the eigenvalues and the eigenvectors of the transfer matrix for spin-ladder model with open boundary conditions. Based on the reflection equation, we find the general diagonal solution, which determines the general boundary interaction in the Hamiltonian. We introduce the spin-ladder model with open boundary conditions. By finding the solution K ± of the reflection equation which determines the nontrivial boundary terms in the Hamiltonian, we diagonalize the transfer matrix of the spin-ladder model with open boundary conditions in the framework of nested BA.

Bethe-salpeter equation from many-body perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Sander, Tobias; Starke, Ronald; Kresse, Georg [Computational Materials Physics, University of Vienna, Sensengasse 8/12, 1090 Vienna (Austria)

2013-07-01

The Green function formalism is a powerful tool to calculate not only electronic structure within the quasi-particle (QP) picture, but it also gives access to optical absorption spectra. Starting from QP energies within the GW method, the polarizability, as central quantity, is calculated from the solution of a Bethe-Salpeter-like equation (BSE). It is usually solved within the Tamm-Dancoff Approximation (TDA) which neglects the coupling of resonant (positive frequency branch) and anti-resonant (negative frequency branch) excitations. In this work we solve the full BSE (beyond TDA) based on self-consistently calculated QP orbitals and energies for typical systems. The dielectric function is averaged over many low dimensional shifted k-meshes to obtain k-point converged results. We compare the results to recently introduced approximation to the BSE kernel. Additionally, the time-evolution ansatz is employed to calculate the polarizability, which avoids the direct solution of the BSE.

Stieltjes-Bethe equations in higher genus and branched coverings with even ramifications

Science.gov (United States)

Korotkin, Dmitry

2018-02-01

We describe projective structures on a Riemann surface corresponding to monodromy groups which have trivial SL (2) monodromies around singularities and trivial PSL (2) monodromies along homologically non-trivial loops on a Riemann surface. We propose a natural higher genus analog of Stieltjes-Bethe equations. Links with branched projective structures and with Hurwitz spaces with ramifications of even order are established. We find a higher genus analog of the genus zero Yang-Yang function (the function generating accessory parameters) and describe its similarity and difference with Bergman tau-function on the Hurwitz spaces.

A Cluster-Bethe lattice treatment for the F-center in alkali-halides

International Nuclear Information System (INIS)

Queiroz, S.L.A. de; Koiller, B.; Maffeo, B.; Brandi, H.S.

1977-01-01

The electronic structure of the F-center in alkali-halides with the NaCl structure has been studied using the Cluster-Bethe lattice method. The central cluster has been taken as constituted by the vacancy and the nearest- and second- neighbors to it, respectively, cations and anions. The optical transitions have been calculated and compared to experimental data on the location of the peak of the F-absorption band. The agreement obtained indicates that this method may be used to study properties of this defect in alkali halides [pt

Quantum solitons and their classical relatives: Bethe Ansatz states in soliton sectors of the Sine--Gordon System

International Nuclear Information System (INIS)

Garbaczewski, P.

1982-01-01

Previously we have found that the semiclassical sine--Gordon/Thirring spectrum can be received in the absence of quantum solitons via the spin 1/2 approximation of the quantized sine--Gordon system on a lattice. Later on, we have recovered the Hilbert space of quantum soliton states for the sine--Gordon system. In the present paper we present a derivation of the Bethe Ansatz eigenstates for the generalized ice model in this soliton Hilbert space. We demonstrate that via ''Wick rotation'' of a fundamental parameter of the ice model one arrives at the Bethe Ansatz eigenstates of the quantum sine--Gordon system. The latter is a ''local transition matrix'' ancestor of the coventional sine--Gordon/Thirring model, as derived by Faddeev et al. within the quantum inverse-scattering method. Our result is essentially based on the N< infinity,Δ = 1,m<<1 regime. Consequently, the spectrum received, though resembling the semiclassical one, does not coincide with it at all

The Bethe-Salpeter equation with fermions

International Nuclear Information System (INIS)

Efimov, G.V.

2007-01-01

The Bethe-Salpeter (BS) equation in the ladder approximation is studied within a fermion theory: two fermion fields (constituents) with mass m interacting via an exchange of a scalar field with mass μ. The BS equation can be written in the form of an integral equation in the configuration Euclidean x-space with the symmetric kernel K for which Tr K 2 = ∞ due to the singular character of the fermion propagator. This kernel is represented in the form K = K 0 + K I . The operator K 0 with Tr K 0 2 ∞ is of the 'fall at the center' potential type and describes a continuous spectrum only. Besides the presence of this operator leads to a restriction on the value of the coupling constant. The kernel K I with Tr K I 2 2 c 2 and the variational procedure of calculations of eigenvalues and eigenfunctions can be applied. The quantum pseudoscalar and scalar mesodynamics is considered. The binding energy of the state 1 + (deuteron) as a function of the coupling constant is calculated in the framework of the procedure formulated above. It is shown that this bound state is absent in the pseudoscalar mesodynamics and does exist in the scalar mesodynamics. A comparison with the non-relativistic Schroedinger picture is made. (author)

Bound states of quarks calculated with stochastic integration of the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Salomon, M.

1992-07-01

We have computed the masses, wave functions and sea quark content of mesons in their ground state by integrating the Bethe-Salpeter equation with a stochastic algorithm. This method allows the inclusion of a large set of diagrams. Inspection of the kernel of the equation shows that q-q-bar pairs with similar constituent masses in a singlet spin state exhibit a high bound state which is not present in other pairs. The pion, kaon and eta belongs to this category. 19 refs., 2 figs., 2 tabs

Study of Y and Lu iron garnets using Bethe-Peierls-Weiss method

Science.gov (United States)

Goveas, Neena; Mukhopadhyay, G.; Mukhopadhyay, P.

1994-11-01

We study here the magnetic properties of Y- and Lu- Iron Garnets using the Bethe- Peierls-Weiss method modified to suit complex systems like these Garnets. We consider these Garnets as described by Heisenberg Hamiltonian with two sublattices (a,d) and determine the exchange interaction parameters Jad, Jaa and Jdd by matching the exerimental susceptibility curves. We find Jaa and Jdd to be much smaller than those determined by Néel theory, and consistent with those obtained by the study of spin wave spectra; the spin wave dispersion relation constant obtained using these parameters gives good agreement with the experimental values.

Calculation of scalar products of wave functions and form factors in the framework of the algebraic Bethe ansatz

International Nuclear Information System (INIS)

Slavnov, N.A.

1989-01-01

The Bethe ansatz method is widely used to investigate two-dimensional completely integrable models. In the framework of the quantum inverse scattering method it has proved to be possible to construct an algebraic scheme of the Bethe ansatz, and this has been successfully applied to calculation of correlation functions. One of the important questions of the method is that of the scalar products of the wave functions. In particular, knowledge of the properties of the scalar products is necessary for investigating the form factors and correlation function. In the present paper the author considers a generalized model with R matrix of the model of the nonlinear Schroedinger equation. The main formulas and notation are given in Sec. 2. In Sec. 3 he calculates the scalar product of an arbitrary function and an eigenfunction of the Hamiltonian. The generalized two-site model is introduced in Sec. 4. In Sec. 5 he calculates the form factor of the particle number operator

Perturbation theory for the Bethe-Salpeter equation in the field of a plane electromagnetic wave

International Nuclear Information System (INIS)

Starostin, V.S.; Litskevich, I.K.

1990-01-01

The completeness and orthogonality of the solutions of the Bethe-Salpeter equation is proven. A correct derivation of perturbation-theory equations is given. A generalization that includes the field of a plane electromagnetic wave is proposed. The rate of one-photon annihilation of positronium in this field is calculated. If the one-photon decay is allowed, the stationary states of the system are found (states of light-positronium)

Probabilistic image processing by means of the Bethe approximation for the Q-Ising model

International Nuclear Information System (INIS)

Tanaka, Kazuyuki; Inoue, Jun-ichi; Titterington, D M

2003-01-01

The framework of Bayesian image restoration for multi-valued images by means of the Q-Ising model with nearest-neighbour interactions is presented. Hyperparameters in the probabilistic model are determined so as to maximize the marginal likelihood. A practical algorithm is described for multi-valued image restoration based on the Bethe approximation. The algorithm corresponds to loopy belief propagation in artificial intelligence. We conclude that, in real world grey-level images, the Q-Ising model can give us good results

Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach

Energy Technology Data Exchange (ETDEWEB)

Diana Nicmorus, Gernot Eichmann, Reinhard Alkofer

2010-12-01

We investigate the electromagnetic form factors of the Delta and the Omega baryons within the Poincare-covariant framework of Dyson-Schwinger and Bethe-Salpeter equations. The three-quark core contributions of the form factors are evaluated by employing a quark-diquark approximation. We use a consistent setup for the quark-gluon dressing, the quark-quark bound-state kernel and the quark-photon interaction. Our predictions for the multipole form factors are compatible with available experimental data and quark-model estimates. The current-quark mass evolution of the static electromagnetic properties agrees with results provided by lattice calculations.

Bethe-Salpeter kernels and particle structure in the Yukawa2 quantum field theory

International Nuclear Information System (INIS)

Cooper, A.S.

1981-01-01

The author discusses the extension to the (weakly coupled) Yukawa quantum field theory in two space-time dimensions (Y 2 ), with equal bare masses, of some techniques used in the analysis of particle structure for weakly coupled even P(PHI) 2 . In particular he considers existence, regularity, and decay properties for the inverse two point functions and various Bethe-Salpeter kernels of the theory. These properties suffice to ensure that in the +-2 fermion sectors the mass spectrum is discrete below 2m 0 and the S-matrix is unitary up to 2m 0 + epsilon. (Auth.)

The electronic structure of the F-center in alkali-halides-The Bethe cluster - lattice

International Nuclear Information System (INIS)

Queiroz, S.L.A. de.

1977-07-01

The electronic structure of the F-center in alkali-halides with the NaCl structure has been studied using the Bethe Cluster lattice method. The central cluster has been taken as constituted by the vacancy and the nearest- and second-neighbors to it, respectively cations and anions. The optical transitions have been calculated and compared to experimental data on the location of the peak of the F-absorption band. The agreement obtained indicates that this method may be used to study properties of this defect in alkali halides. (Author) [pt

Numerical Solutions of One Reduced Bethe-Salpeter Equation for the Coulombic Bound States Composed of Virtual Constituents

Science.gov (United States)

Chen, Jiao-Kai

2018-04-01

We present one reduction of the Bethe-Salpeter equation for the bound states composed of two off-mass-shell constituents. Both the relativistic effects and the virtuality effects can be considered in the obtained spinless virtuality distribution equation. The eigenvalues of the spinless virtuality distribution equation are perturbatively calculated and the bound states e+e-, μ+μ-, τ+τ-, μ+e-, and τ+e- are discussed.

Asymptotic Bethe ansatz S-matrix and Landau-Lifshitz-type effective 2d actions

International Nuclear Information System (INIS)

Roiban, R; Tirziu, A; Tseytlin, A A

2006-01-01

Motivated by the desire to relate Bethe ansatz equations for anomalous dimensions found on the gauge-theory side of the AdS/CFT correspondence to superstring theory on AdS 5 x S 5 we explore a connection between the asymptotic S-matrix that enters the Bethe ansatz and an effective two-dimensional quantum field theory. The latter generalizes the standard 'non-relativistic' Landau-Lifshitz (LL) model describing low-energy modes of ferromagnetic Heisenberg spin chain and should be related to a limit of superstring effective action. We find the exact form of the quartic interaction terms in the generalized LL-type action whose quantum S-matrix matches the low-energy limit of the asymptotic S-matrix of the spin chain of Beisert, Dippel and Staudacher (BDS). This generalizes to all orders in the 't Hooft coupling λ an earlier computation of Klose and Zarembo of the S-matrix of the standard LL model. We also consider a generalization to the case when the spin-chain S-matrix contains an extra 'string' phase and determine the exact form of the LL 4-vertex corresponding to the low-energy limit of the ansatz of Arutyunov, Frolov and Staudacher (AFS). We explain the relation between the resulting 'non-relativistic' non-local action and the second-derivative string sigma model. We comment on modifications introduced by strong-coupling corrections to the AFS phase. We mostly discuss the SU(2) sector but also present generalizations to the SL(2) and SU(1|1) sectors, confirming universality of the dressing phase contribution by matching the low-energy limit of the AFS-type spin-chain S-matrix with tree-level string-theory S-matrix

Bethe-Salpeter equation for non-self conjugate mesons in a power-law potential

International Nuclear Information System (INIS)

Ikhdair, S.M.

1992-07-01

We develop an approach to the solution of the spinless Bethe-Salpeter equation for the different-mass case. Although the calculations are developed for spin-zero particles in any arbitrary spherically symmetric potential, the non-Coulombic effective power-law potential is used as a kernel to produce the spin-averaged bound states of the non-self-conjugate mesons. The analytical formulae are also applicable to the self-conjugate mesons in the equal-mass case. The flavor-independent case is investigated in this work. The calculations are carried out to the third-order correction of the energy series. Results are consistent with those obtained before. (author). 14 refs, 1 tab

Electromagnetic production of trimuons in muon scattering: Bethe-Heitler reactions with muon and heavy-lepton pairs

International Nuclear Information System (INIS)

Ganapathi, V.; Smith, J.

1981-01-01

We analyze the Bethe-Heitler production of muon and heavy-lepton pairs using high-energy muon beams on a variety of targets. We give results for coherent production from a nucleus, for incoherent production from individual protons and neutrons, and for deep-inelastic production. Differential distributions are presented for the final leptons and the effects of experimental cuts are considered. This work complements our previous study of trimuon production via muon radiation, Compton radiation, and hadronic final-state interactions

Quarkonia in the Bethe--Salpeter formalism with background fields

International Nuclear Information System (INIS)

Mathur, Y.K.; Mitra, A.N.

1989-01-01

A QCD-oriented Bethe--Salpeter (BS) equation for a q bar q system is formulated in which the quark 4-momenta p μ are modified as p μ →p μ -gA μ (x) in the inverse propagators therein, and a Fock--Schwinger (FS) gauge expansion is employed for the gluon fields A μ (x). The first term (∼x μ ) of the FS representation yields a harmonic kernel when the BS equation is reduced to a 3-dimensional level via the null-plane ansatz (NPA). It also generates a spin-dependent interaction proportional to (j 1 +s 1 )·(j 2 +s 2 ), in close parallel to a J·S term generated by a vector-like (γ (1) gamma(2)) harmonic model for the q bar q interaction proposed earlier by the Delhi Group. A possible mechanism for confinement in an asymptotically linear scene is proposed within the BS framework, taking cue partly from the suggestions of multiple correlation effects (Shifman), and partly from the postulation of stochastic fields (Simonov)

La cerámica Khirbet Kerak (Beth Yerah, Israel y la etnicidad: un enfoque alternativo

Directory of Open Access Journals (Sweden)

Bernardo Gandulla

2007-07-01

Full Text Available La cerámica Khirbet Kerak, descubierta en el sudoeste del Mar de Galilea en 1930 por W. F. Albright, ha sido desde entonces motivo de muchas controversias. Las razones de las discusiones en torno a este estilo radican  en su carácter aparentemente intrusivo en Palestina, entre el 2800-2400  a.C., puesto que esta cerámica es típica en la Cultura Transcaucásica Temprana o Cultura Kura-Araxes y en Siria Septentrional, durante el Bronce Antiguo, siendo especialmente abundante en la etapa final de este período. Sin embargo los estudios realizados en Beth Shan (Chazan y McGovern, ver n. 17, muestran que los materiales Khirbet Kerak fueron de producción local lo que parece descartar su carácter intrusivo. Por tanto, desde nuestro punto de vista, el “fenómeno Khirbet Kerak” constituye así un hito de singular importancia en la conformación de las tradiciones culturales de Canaan a partir de un sustrato etnocultural común hurrita, en un eje de interacción cultural norte a sur desde la región del Lago Van, que habrá de proyectarse de distintas formas en la macrorregión alcanzando hasta los antiguos hebreos, en cuanto cananeos, como se reflejan en instituciones del derecho privado presentes en las narraciones del Génesis.Palabras clave: Canaán - Bronce Antiguo - Beth Yerah - Khirbet Kerak - Hurritas- Hebreos

On Condensation Properties of Bethe Roots Associated with the XXZ Chain

Science.gov (United States)

Kozlowski, Karol K.

2018-02-01

I prove that the Bethe roots describing either the ground state or a certain class of "particle-hole" excited states of the XXZ spin-1/2 chain in any sector with magnetisation m \\in [0;1/2] exist, are uniquely defined, and form, in the infinite volume limit, a dense distribution on a subinterval of R. The results hold for any value of the anisotropy {Δ ≥ -1}. In fact, I establish an even stronger result, namely the existence of an all order asymptotic expansion of the counting function associated with such roots. As a corollary, these results allow one to prove the existence and form of the infinite volume limit of various observables attached to the model -the excitation energy, momentum, the zero temperature correlation functions, so as to name a few- that were argued earlier in the literature.

A systematic approach to sketch Bethe-Salpeter equation

Directory of Open Access Journals (Sweden)

Qin Si-xue

2016-01-01

Full Text Available To study meson properties, one needs to solve the gap equation for the quark propagator and the Bethe-Salpeter (BS equation for the meson wavefunction, self-consistently. The gluon propagator, the quark-gluon vertex, and the quark–anti-quark scattering kernel are key pieces to solve those equations. Predicted by lattice-QCD and Dyson-Schwinger analyses of QCD’s gauge sector, gluons are non-perturbatively massive. In the matter sector, the modeled gluon propagator which can produce a veracious description of meson properties needs to possess a mass scale, accordingly. Solving the well-known longitudinal Ward-Green-Takahashi identities (WGTIs and the less-known transverse counterparts together, one obtains a nontrivial solution which can shed light on the structure of the quark-gluon vertex. It is highlighted that the phenomenologically proposed anomalous chromomagnetic moment (ACM vertex originates from the QCD Lagrangian symmetries and its strength is proportional to the magnitude of dynamical chiral symmetry breaking (DCSB. The color-singlet vector and axial-vector WGTIs can relate the BS kernel and the dressed quark-gluon vertex to each other. Using the relation, one can truncate the gap equation and the BS equation, systematically, without violating crucial symmetries, e.g., gauge symmetry and chiral symmetry.

Log-gamma directed polymer with fixed endpoints via the replica Bethe Ansatz

International Nuclear Information System (INIS)

Thiery, Thimothée; Le Doussal, Pierre

2014-01-01

We study the model of a discrete directed polymer (DP) on a square lattice with homogeneous inverse gamma distribution of site random Boltzmann weights, introduced by Seppalainen (2012 Ann. Probab. 40 19–73). The integer moments of the partition sum, Z n -bar , are studied using a transfer matrix formulation, which appears as a generalization of the Lieb–Liniger quantum mechanics of bosons to discrete time and space. In the present case of the inverse gamma distribution the model is integrable in terms of a coordinate Bethe Ansatz, as discovered by Brunet. Using the Brunet-Bethe eigenstates we obtain an exact expression for the integer moments of Z n -bar for polymers of arbitrary lengths and fixed endpoint positions. Although these moments do not exist for all integer n, we are nevertheless able to construct a generating function which reproduces all existing integer moments and which takes the form of a Fredholm determinant (FD). This suggests an analytic continuation via a Mellin–Barnes transform and we thereby propose a FD ansatz representation for the probability distribution function (PDF) of Z and its Laplace transform. In the limit of a very long DP, this ansatz yields that the distribution of the free energy converges to the Gaussian unitary ensemble (GUE) Tracy-Widom distribution up to a non-trivial average and variance that we calculate. Our asymptotic predictions coincide with a result by Borodin et al (2013 Commun. Math. Phys. 324 215–32) based on a formula obtained by Corwin et al (2011 arXiv:1110.3489) using the geometric Robinson–Schensted–Knuth (gRSK) correspondence. In addition we obtain the dependence on the endpoint position and the exact elastic coefficient at a large time. We argue the equivalence between our formula and that of Borodin et al. As we will discuss, this provides a connection between quantum integrability and tropical combinatorics. (paper)

Quantum quench dynamics of the attractive one-dimensional Bose gas via the coordinate Bethe ansatz

Directory of Open Access Journals (Sweden)

Jan C. Zill, Tod M. Wright, Karen V. Kheruntsyan, Thomas Gasenzer, Matthew J. Davis

2018-02-01

Full Text Available We use the coordinate Bethe ansatz to study the Lieb-Liniger model of a one-dimensional gas of bosons on a finite-sized ring interacting via an attractive delta-function potential. We calculate zero-temperature correlation functions for seven particles in the vicinity of the crossover to a localized solitonic state and study the dynamics of a system of four particles quenched to attractive interactions from the ideal-gas ground state. We determine the time evolution of correlation functions, as well as their temporal averages, and discuss the role of bound states in shaping the postquench correlations and relaxation dynamics.

"Her mouth is medicine": Beth Brant and Paula Gunn Allen's decolonizing queer erotics.

Science.gov (United States)

Burford, Arianne

2013-01-01

This article asserts the need to recognize the complexity of the theoretical work of more lesbian Native American writers, focusing specifically Beth Brant (Bay of Quinte Mohawk) and Paula Gunn Allen (Laguna Pueblo). Their poetry and short stories provide a theoretically nuanced analysis of how heteronormativity is intertwined in and dependent on colonialism, and thus a methodology for Queer Theory that requires an understanding of it in relation to colonialism. They reject heteronormative Pocahontas fantasies about Native women, offering a lesbian-based tactic for decolonization through the expression of erotic desire. This article demonstrates the endless possibilities for fierce queer resistance, revolutionary change, and healing from the trauma of genocide and the accompanying colonialist heteropatriarchal disciplining of Native women's bodies.

QCD-oriented Bethe-Salpeter dynamics for all flavours, light and heavy

International Nuclear Information System (INIS)

Mitra, A.N.

1987-01-01

A QCD oriented Bethe-Salpeter approach with a vector-like confinement which looks harmonic in the instantaneous approximation (IA), was found to describe several features of qanti q and qqq systems (mass spectra and structural properties) adequately, with little extra assumptions. The model had the following drawbacks: (a) The IA, being non-covariant, had restricted the application of the model to slow hadrons; (b) The zero-point energies were poorly described without additional assumptions; (c) The predicted Qanti Q spacings were too large for the data. These limitations have recently been overcome and the model now has a wide sweep of successful predictions, not only on the mass spectra for both light and heavy sectors, but also for transition amplitudes involving fast moving hadrons. A sketchy but consolidated account is given of the main features of the model (as modified through the new assumptions) and the nature of its successes on the experimental front (mostly mass spectra) are indicated. 20 refs

Bethe-Salpeter equation for fermion-antifermion system in the ladder approximation

International Nuclear Information System (INIS)

Fukui, Ichio; Seto, Noriaki; Yoshida, Toshihiro.

1977-01-01

The Bethe-Salpeter (B-S) equation is important for studying hadron physics. Especially intensive investigation on the fermion-antifermion B-S equation is indispensable for the phenomenological studies of hardrons. However, many components of the B-S amplitude and the Wick-rotated integral kernel of non-Fredholm type have prevented from knowing details the solutions even in the ladder approximation. Some particular solutions are known in case of the vanishing four-momenta of bound states. The B-S equation for the bound state of fermion-anti-fermion system interacting through vector (axial-vector) particle exchange was studied in the ladder approximation with Feynman gauge. The reduced equations were obtained for suitably decomposed amplitude, and it is shown that, in the S-wave case, the coupled equations separate into two parts. In the nonrelativistic limit, large components of the amplitude satisfy the Wick-Cutkosky equation, and small components are expressed in terms of the large ones. Equations are derived for the equal-time amplitudes. (Kobatake, H.)

The decay constants of heavy-light mesons in a two-tier Bethe-Salpeter model

International Nuclear Information System (INIS)

Pagnamenta, A.; Illinois Univ., Chicago, IL; Gupta, K.K.; Mitra, A.N.; Singh, N.N.; Ramanathan, R.

1990-01-01

Leptonic decay widths for pseudoscalar mesons are calculated in a QCD-motivated Bethe-Salpeter formalism on a two-tier basis. This model, which is characterised by a Lorentz-invariant confining kernel that depends on the relativistic reduced mass defined in accordance with the Wightman-Garding definition of the internal 4-momenta q μ , has already shown precision fits to the spectra of qq-bar, qQ-bar and qqq hadrons apart from exhibiting an eplicit Regge-asymptotic behaviour (M 2 ∼N). The leptonic decay constants thus obtained with no free parameters, are (in MeV units), f P =134(π), 166(K); 158(D); 94.9(B), 114(B S ). (author)

Projecting the Bethe-Salpeter Equation onto the Light-Front and Back: A Short Review

International Nuclear Information System (INIS)

Frederico, T.; Salme, G.

2011-01-01

The technique of projecting the four-dimensional two-body Bethe-Salpeter equation onto the three-dimensional Light-Front hypersurface, combined with the quasi-potential approach, is briefly illustrated, by placing a particular emphasis on the relation between the projection method and the effective dynamics of the valence component of the Light-Front wave function. Some details on how to construct the Fock expansion of both (a) the Light-Front effective interaction and (b) the electromagnetic current operator, satisfying the proper Ward-Takahashi identity, will be presented, addressing the relevance of the Fock content in the operators living onto the Light-Front hypersurface. Finally, the generalization of the formalism to the three-particle case will be outlined. (author)

The convergence of the binding energy expansion in the Brueckner-Bethe-Goldstone theory of nuclear matter

International Nuclear Information System (INIS)

Grange, P.; Lejeune, A.

1979-01-01

Two, three- and four-body contributions to the binding energy of nuclear matter are evaluated in the framework of the Bethe-Brueckner expansion. Special attention is devoted to the choice of the auxillary single particle field and to the potential diagrams at the level of three- and four-hole lines present when such a field is different from zero. Two nucleon-nucleon interactions are used: a model interaction V 1 and the Reid soft-core interaction. For V 1 our results are compared with those obtained from variational calculations; this comparison supports the reliability of the perturbative expansion. (Auth.)

Projectile-z3 and -z4 corrections to basic Bethe-Bloch stopping power theory and mean excitation energies of Al, Si, Ni, Ge, Se, Y, Ag and Au

International Nuclear Information System (INIS)

Porter, L.E.; Bryan, S.R.

1980-01-01

Three independent sets of measurements of the stopping power of solid elemental targets for alpha particles were previously analyzed in terms of basic Bethe-Bloch theory with the low velocity projectile-z 3 correction term included. These data for Al, Si, Ni, Ge, Se, Y, Ag and Au have now been analyzed with the Bloch projectile-z 4 term and a revised projectile-z 3 term incorporated in the Bethe-Bloch formula, the projectile-z 3 revision having been effected by variation of the single free parameter of the projectile-z 3 effect formalism. The value of this parameter, fixed at 1.8 in previous studies, which counteracts inclusion of the projectile-z 4 term is 1.3 +- 0.1 for all target elements except Si. (orig.)

Elastic eD scattering in the Bethe-Salpeter approach for the deuteron with the positive- and negative-energy states

International Nuclear Information System (INIS)

Bondarenko, S.G.; Burov, V.V.; Hamamoto, N.; Manabe, Y.; Hosaka, A.; Toki, H.

2005-01-01

Recent results obtained by the application of the Bethe-Salpeter approach to the analysis of elastic electron-deuteron scattering with the separable NN kernel are presented. We analyze the impact of the P waves (negative-energy components) on the electromagnetic properties of the deuteron and compare it with experimental data. It was shown that the contribution of the P waves must be taken into account to explain tensor polarization and charge form factor of the deuteron

Site-occupation embedding theory using Bethe ansatz local density approximations

Science.gov (United States)

Senjean, Bruno; Nakatani, Naoki; Tsuchiizu, Masahisa; Fromager, Emmanuel

2018-06-01

Site-occupation embedding theory (SOET) is an alternative formulation of density functional theory (DFT) for model Hamiltonians where the fully interacting Hubbard problem is mapped, in principle exactly, onto an impurity-interacting (rather than a noninteracting) one. It provides a rigorous framework for combining wave-function (or Green function)-based methods with DFT. In this work, exact expressions for the per-site energy and double occupation of the uniform Hubbard model are derived in the context of SOET. As readily seen from these derivations, the so-called bath contribution to the per-site correlation energy is, in addition to the latter, the key density functional quantity to model in SOET. Various approximations based on Bethe ansatz and perturbative solutions to the Hubbard and single-impurity Anderson models are constructed and tested on a one-dimensional ring. The self-consistent calculation of the embedded impurity wave function has been performed with the density-matrix renormalization group method. It has been shown that promising results are obtained in specific regimes of correlation and density. Possible further developments have been proposed in order to provide reliable embedding functionals and potentials.

An investigation of relativistic microscopic optical potential in terms of relativistic Brueckner-Bethe-Goldstone equation

International Nuclear Information System (INIS)

Chen Baoqiu; Ma Zhongyu

1992-01-01

Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation. The complex effective mass of a nucleon is determined by a fit to 200 MeV p- 40 Ca scattering data. The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p- 16O , 40 Ca, 90 Zr and 208 Pb scattering in energy range from 160 to 800 MeV. The microscopic optical potential is used to study the proton- 40 Ca scattering problem at 200 MeV. The results, such as differential cross section, analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential

Generalized structure of hadron-quark vertex function in Bethe-Salpeter framework: applications to leptonic decays of V-mesons

Energy Technology Data Exchange (ETDEWEB)

Bhatnagar, Shashank [Department of Physics, Addis Ababa University, PO Box 101739, Addis Ababa (Ethiopia); Li Shiyuan [Department of Physics, Shandong University, Jinan, 250100 (China)

2006-07-15

We employ the framework of the Bethe-Salpeter equation under a covariant instantaneous ansatz to study the leptonic decays of vector mesons. The structure of the hadron-quark vertex function {gamma} is generalized to include various Dirac covariants (other than i{gamma} . {epsilon}) from their complete set. They are incorporated in accordance with a naive power counting rule order-by-order in powers of the inverse of the meson mass. The decay constants for {rho}, {omega} and {phi} mesons are calculated with the incorporation of leading-order covariants.

Generalized structure of hadron-quark vertex function in Bethe-Salpeter framework: applications to leptonic decays of V-mesons

International Nuclear Information System (INIS)

Bhatnagar, Shashank; Li Shiyuan

2006-01-01

We employ the framework of the Bethe-Salpeter equation under a covariant instantaneous ansatz to study the leptonic decays of vector mesons. The structure of the hadron-quark vertex function Γ is generalized to include various Dirac covariants (other than iγ . ε) from their complete set. They are incorporated in accordance with a naive power counting rule order-by-order in powers of the inverse of the meson mass. The decay constants for ρ, ω and φ mesons are calculated with the incorporation of leading-order covariants

Density matrix renormalization group simulations of SU(N ) Heisenberg chains using standard Young tableaus: Fundamental representation and comparison with a finite-size Bethe ansatz

Science.gov (United States)

Nataf, Pierre; Mila, Frédéric

2018-04-01

We develop an efficient method to perform density matrix renormalization group simulations of the SU(N ) Heisenberg chain with open boundary conditions taking full advantage of the SU(N ) symmetry of the problem. This method is an extension of the method previously developed for exact diagonalizations and relies on a systematic use of the basis of standard Young tableaux. Concentrating on the model with the fundamental representation at each site (i.e., one particle per site in the fermionic formulation), we have benchmarked our results for the ground-state energy up to N =8 and up to 420 sites by comparing them with Bethe ansatz results on open chains, for which we have derived and solved the Bethe ansatz equations. The agreement for the ground-state energy is excellent for SU(3) (12 digits). It decreases with N , but it is still satisfactory for N =8 (six digits). Central charges c are also extracted from the entanglement entropy using the Calabrese-Cardy formula and agree with the theoretical values expected from the SU (N) 1 Wess-Zumino-Witten conformal field theories.

Bethe, Oppenheimer, Teller and the Fermi Award: Norris Bradbury Speaks

Energy Technology Data Exchange (ETDEWEB)

Meade, Roger Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-04-28

In 1956 the Enrico Fermi Presidential Award was established to recognize scientists, engineers, and science policymakers who gave unstintingly over their careers to advance energy science and technology. The first recipient was John von Neumann. .1 Among those scientists who were thought eligible for the award were Hans Bethe, J. Robert Oppenheimer, and Edward Teller. In 1959 Norris Bradbury was asked to comment on the relative merits of each these three men, whom he knew well from their affiliation with Los Alamos. Below is a reproduction of the letter Bradbury sent to Dr. Warren C. Johnson of the AEC’s General Advisory Committee(GAC) containing his evaluation of each man. The letter might surprise those not accustomed to Bradbury’s modus operandi of providing very detailed and forthright answers to the AEC. The letter, itself, was found in cache of old microfilm. Whether because of the age of the microfilm or the quality of the filming process, portions of the letter are not legible. Where empty brackets appear, the word or words could not be read or deduced. Words appearing in brackets are guesses that appear, from the image, to be what was written. These guesses, of course, are just that – guesses.

Efficient implementation of core-excitation Bethe-Salpeter equation calculations

Science.gov (United States)

Gilmore, K.; Vinson, John; Shirley, E. L.; Prendergast, D.; Pemmaraju, C. D.; Kas, J. J.; Vila, F. D.; Rehr, J. J.

2015-12-01

We present an efficient implementation of the Bethe-Salpeter equation (BSE) method for obtaining core-level spectra including X-ray absorption (XAS), X-ray emission (XES), and both resonant and non-resonant inelastic X-ray scattering spectra (N/RIXS). Calculations are based on density functional theory (DFT) electronic structures generated either by ABINIT or QuantumESPRESSO, both plane-wave basis, pseudopotential codes. This electronic structure is improved through the inclusion of a GW self energy. The projector augmented wave technique is used to evaluate transition matrix elements between core-level and band states. Final two-particle scattering states are obtained with the NIST core-level BSE solver (NBSE). We have previously reported this implementation, which we refer to as OCEAN (Obtaining Core Excitations from Ab initio electronic structure and NBSE) (Vinson et al., 2011). Here, we present additional efficiencies that enable us to evaluate spectra for systems ten times larger than previously possible; containing up to a few thousand electrons. These improvements include the implementation of optimal basis functions that reduce the cost of the initial DFT calculations, more complete parallelization of the screening calculation and of the action of the BSE Hamiltonian, and various memory reductions. Scaling is demonstrated on supercells of SrTiO3 and example spectra for the organic light emitting molecule Tris-(8-hydroxyquinoline)aluminum (Alq3) are presented. The ability to perform large-scale spectral calculations is particularly advantageous for investigating dilute or non-periodic systems such as doped materials, amorphous systems, or complex nano-structures.

Null-plane formulation of Bethe-Salpeter qqq dynamics: Baryon mass spectra

International Nuclear Information System (INIS)

Kulshreshtha, D.S.; Mitra, A.N.

1988-01-01

The Bethe-Salpeter (BS) equation for a qqq system is formulated in the null-plane approximation (NPA) for the BS wave function, as a direct generalization of a corresponding QCD-motivated formalism developed earlier for qq-bar systems. The confinement kernel is assumed vector type (γ/sub μ//sup (1)/γ/sub μ//sup (2)/) for both qq-bar and qq pairs, with identical harmonic structures, and with the spring constant proportional, among other things, to the running coupling constant α/sub s/ (for an explicit QCD motivation). The harmonic kernel is given a suitable Lorentz-invariant definition [not D'Alembertian 2 δ 4 (q)], which is amenable to NPA reduction in a covariant form. The reduced qqq equation in NPA is solved algebraically in a six-dimensional harmonic-oscillator (HO) basis, using the techniques of SO(2,1) algebra interlinked with S 3 symmetry. The results on the nonstrange baryon mass spectra agree well with the data all the way up to N = 6, thus confirming the asymptotic prediction M∼N/sup 2/3/ characteristic of vector confinement in HO form. There are no extra parameters beyond the three basic constants (ω 0 ,C 0 ,m/sub u//sub d/) which were earlier found to provide excellent fits to meson spectra (qq-bar)

Short-distance behavior of the Bethe--Salpeter wave function in the ladder approximation

International Nuclear Information System (INIS)

Guth, A.H.; Soper, D.E.

1975-01-01

We investigate the short-distance behavior of the (Wick-rotated) Bethe--Salpeter wave function for the two spin-1/2 quarks bound by the exchange of a massive vector meson. We use the ladder-model kernel, which has the same p -4 scaling behavior as the true kernel in a theory with a fixed point of the renormalization group at g not equal to 0. For a bound state with the quantum numbers of the pion, the leading asymptotic behavior is chi (q/sup μ/) approx. cq/sup -4 + epsilon(g)/γ 5 , where epsilon (g) =1- (1-g 2 /π 2 ) 1 / 2 . Our method also provides the full asymptotic series, although it should be noted that the nonleading terms will depend on the nonleading behavior of the ladder-model kernel. A general term has the form cq - /sup a/(lnq)/sup n/phi (q/sup μ/), where c is an unknown constant, a may be integral or nonintegral, n is an integer, and phi (q/sup μ/) is a representation function of the rotation group in four dimensions

Optical properties of bulk semiconductors and graphene/boron nitride: the Bethe-Salpeter equation with derivative discontinuity-corrected density functional energies

DEFF Research Database (Denmark)

Yan, Jun; Jacobsen, Karsten W.; Thygesen, Kristian S.

2012-01-01

-dimensional systems of graphene and hexagonal boron-nitride (h-BN) we find good agreement with previous many-body calculations. For the graphene/h-BN interface we find that the fundamental and optical gaps of the h-BN layer are reduced by 2.0 and 0.7 eV, respectively, compared to freestanding h-BN. This reduction......We present an efficient implementation of the Bethe-Salpeter equation (BSE) for optical properties of materials in the projector augmented wave method Grid-based projector-augmented wave method (GPAW). Single-particle energies and wave functions are obtained from the Gritsenko, Leeuwen, Lenthe...

Non-skew-symmetric classical r-matrices, algebraic Bethe ansatz, and Bardeen-Cooper-Schrieffer-type integrable systems

International Nuclear Information System (INIS)

Skrypnyk, T.

2009-01-01

We construct quantum integrable systems associated with non-skew-symmetric gl(2)-valued classical r-matrices. We find a new explicit multiparametric family of such the non-skew-symmetric classical r-matrices. We consider two classes of examples of the corresponding integrable systems, namely generalized Gaudin systems with and without an external magnetic field. In the case of arbitrary r-matrices diagonal in a standard gl(2)-basis, we calculate the spectrum of the corresponding quantum integrable systems using the algebraic Bethe ansatz. We apply these results to a construction of integrable fermionic models and obtain a wide class of integrable Bardeen-Cooper-Schrieffer (BCS)-type fermionic Hamiltonians containing the pairing and electrostatic interaction terms. We also consider special cases when the corresponding integrable Hamiltonians contain only pairing interaction term and are exact analogs of the 'reduced BCS Hamiltonian' of Richardson

Magnetic properties of the mixed ferrimagnetic ternary system with a single-ion anisotropy on the Bethe lattice

Energy Technology Data Exchange (ETDEWEB)

Deviren, Bayram [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); School of Computational Science, Florida State University, Tallahassee, FL 32306-4120 (United States); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr

2009-05-15

The magnetic properties of the ternary system ABC consisting of spins {sigma}=1/2 , S=1, and m=3/2 are investigated on the Bethe lattice by using the exact recursion relations. We consider both ferromagnetic and antiferromagnetic exchange interactions. The exact expressions for magnetizations and magnetic susceptibilities are found, and thermal behaviors of magnetizations and susceptibilities are studied. We construct the phase diagrams and find that the system exhibits one, two or even three compensation temperatures depending on the values of the interaction parameters in the Hamiltonian. Moreover, the system undergoes a second-order phase transition for the coordination number q{<=}3 and a second- and first-order phase transitions for q>3; hence the system gives a tricritical point. The system also exhibits the reentrant behaviors.

Magnetic properties of the mixed ferrimagnetic ternary system with a single-ion anisotropy on the Bethe lattice

International Nuclear Information System (INIS)

Deviren, Bayram; Canko, Osman; Keskin, Mustafa

2009-01-01

The magnetic properties of the ternary system ABC consisting of spins σ=1/2 , S=1, and m=3/2 are investigated on the Bethe lattice by using the exact recursion relations. We consider both ferromagnetic and antiferromagnetic exchange interactions. The exact expressions for magnetizations and magnetic susceptibilities are found, and thermal behaviors of magnetizations and susceptibilities are studied. We construct the phase diagrams and find that the system exhibits one, two or even three compensation temperatures depending on the values of the interaction parameters in the Hamiltonian. Moreover, the system undergoes a second-order phase transition for the coordination number q≤3 and a second- and first-order phase transitions for q>3; hence the system gives a tricritical point. The system also exhibits the reentrant behaviors

Light-quarkonium spectra and orbital-angular-momentum decomposition in a Bethe-Salpeter-equation approach

Energy Technology Data Exchange (ETDEWEB)

Hilger, T.; Krassnigg, A. [University of Graz, NAWI Graz, Institute of Physics, Graz (Austria); Gomez-Rocha, M. [ECT*, Villazzano, Trento (Italy)

2017-09-15

We investigate the light-quarkonium spectrum using a covariant Dyson-Schwinger-Bethe-Salpeter-equation approach to QCD. We discuss splittings among as well as orbital angular momentum properties of various states in detail and analyze common features of mass splittings with regard to properties of the effective interaction. In particular, we predict the mass of anti ss exotic 1{sup -+} states, and identify orbital angular momentum content in the excitations of the ρ meson. Comparing our covariant model results, the ρ and its second excitation being predominantly S-wave, the first excitation being predominantly D-wave, to corresponding conflicting lattice-QCD studies, we investigate the pion-mass dependence of the orbital-angular-momentum assignment and find a crossing at a scale of m{sub π} ∝ 1.4 GeV. If this crossing turns out to be a feature of the spectrum generated by lattice-QCD studies as well, it may reconcile the different results, since they have been obtained at different values of m{sub π}. (orig.)

Multicritical phase diagrams of the spin-((3)/(2)) Blume-Emery-Griffiths model on the Bethe lattice using the recursion method

International Nuclear Information System (INIS)

Ekiz, Cesur; Albayrak, Erhan; Keskin, Mustafa.

2003-01-01

The multicritical behaviour of the spin-((3)/(2)) Blume-Emery-Griffiths model with bilinear and biquadratic exchange interactions and single-ion crystal field is studied on the Bethe lattice by introducing two-sublattices A and B within the exact recursion equations. Exact expressions for the free energy, the Curie or second-order phase transition temperatures, as well as for the magnetization and quadrupolar moment order parameters are obtained. The general procedure of investigation of critical properties is discussed and phase diagrams are obtained, in particular, for negative biquadratic couplings. The phase diagram of the model exhibits a rich variety of behaviours. Results are compared with other approximate methods

Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe-Heitler process in measurements on a hydrogen target

International Nuclear Information System (INIS)

Airapetian, A.; Akopov, Z.

2009-09-01

Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996-2005 with the HERMES spectrometer are analyzed to yield asymmetries with respect to the combined dependence of the cross section on beam helicity and charge, thereby revealing previously unseparated contributions from deeply virtual Compton scattering and its interference with the Bethe-Heitler process. The integrated luminosity is sufficient to show correlated dependences on two kinematic variables, and provides the most precise determination of the dependence on only the beam charge. (orig.)

Beth-Uhlenbeck approach for repulsive interactions between baryons in a hadron gas

Science.gov (United States)

Vovchenko, Volodymyr; Motornenko, Anton; Gorenstein, Mark I.; Stoecker, Horst

2018-03-01

The quantum mechanical Beth-Uhlenbeck (BU) approach for repulsive hard-core interactions between baryons is applied to the thermodynamics of a hadron gas. The second virial coefficient a2—the "excluded volume" parameter—calculated within the BU approach is found to be temperature dependent, and it differs dramatically from the classical excluded volume (EV) model result. At temperatures T =100 -200 MeV, the widely used classical EV model underestimates the EV parameter for nucleons at a given value of the nucleon hard-core radius by large factors of 3-4. Previous studies, which employed the hard-core radii of hadrons as an input into the classical EV model, have to be re-evaluated using the appropriately rescaled EV parameters. The BU approach is used to model the repulsive baryonic interactions in the hadron resonance gas (HRG) model. Lattice data for the second- and fourth-order net baryon susceptibilities are described fairly well when the temperature dependent BU baryonic excluded volume parameter corresponds to nucleon hard-core radii of rc=0.25 -0.3 fm. Role of the attractive baryonic interactions is also considered. It is argued that HRG model with a constant baryon-baryon EV parameter vN N≃1 fm3 provides a simple yet efficient description of baryon-baryon interaction in the crossover temperature region.

Modification of the quantum-mechanical equations for the system of charged Dirac particles by including additional tensor terms of the Pauli type. Pt. 1. [Amplified Bethe-Salpeter, radiative corrections, fine structure

Energy Technology Data Exchange (ETDEWEB)

Janyszek, H [Uniwersytet Mikolaja Kopernika, Torun (Poland). Instytut Fizyki

1974-01-01

A new modified quasirelativistic equation (different from that of Breit) for N charged Dirac particles in the external stationary electromagnetic field is proposed. This equation is an amplified quantum-mechanical Bethe-Salpeter equation obtained by adding (in a semi-phenomenological manner) terms which take into account radiative corrections. The application of this approximate equations is limited to third order terms in the fine structure constant ..cap alpha...

Cycle-Based Cluster Variational Method for Direct and Inverse Inference

Science.gov (United States)

Furtlehner, Cyril; Decelle, Aurélien

2016-08-01

Large scale inference problems of practical interest can often be addressed with help of Markov random fields. This requires to solve in principle two related problems: the first one is to find offline the parameters of the MRF from empirical data (inverse problem); the second one (direct problem) is to set up the inference algorithm to make it as precise, robust and efficient as possible. In this work we address both the direct and inverse problem with mean-field methods of statistical physics, going beyond the Bethe approximation and associated belief propagation algorithm. We elaborate on the idea that loop corrections to belief propagation can be dealt with in a systematic way on pairwise Markov random fields, by using the elements of a cycle basis to define regions in a generalized belief propagation setting. For the direct problem, the region graph is specified in such a way as to avoid feed-back loops as much as possible by selecting a minimal cycle basis. Following this line we are led to propose a two-level algorithm, where a belief propagation algorithm is run alternatively at the level of each cycle and at the inter-region level. Next we observe that the inverse problem can be addressed region by region independently, with one small inverse problem per region to be solved. It turns out that each elementary inverse problem on the loop geometry can be solved efficiently. In particular in the random Ising context we propose two complementary methods based respectively on fixed point equations and on a one-parameter log likelihood function minimization. Numerical experiments confirm the effectiveness of this approach both for the direct and inverse MRF inference. Heterogeneous problems of size up to 10^5 are addressed in a reasonable computational time, notably with better convergence properties than ordinary belief propagation.

A Binary-Encounter-Bethe Approach to Simulate DNA Damage by the Direct Effect

Science.gov (United States)

Plante, Ianik; Cucinotta, Francis A.

2013-01-01

The DNA damage is of crucial importance in the understanding of the effects of ionizing radiation. The main mechanisms of DNA damage are by the direct effect of radiation (e.g. direct ionization) and by indirect effect (e.g. damage by.OH radicals created by the radiolysis of water). Despite years of research in this area, many questions on the formation of DNA damage remains. To refine existing DNA damage models, an approach based on the Binary-Encounter-Bethe (BEB) model was developed[1]. This model calculates differential cross sections for ionization of the molecular orbitals of the DNA bases, sugars and phosphates using the electron binding energy, the mean kinetic energy and the occupancy number of the orbital. This cross section has an analytic form which is quite convenient to use and allows the sampling of the energy loss occurring during an ionization event. To simulate the radiation track structure, the code RITRACKS developed at the NASA Johnson Space Center is used[2]. This code calculates all the energy deposition events and the formation of the radiolytic species by the ion and the secondary electrons as well. We have also developed a technique to use the integrated BEB cross section for the bases, sugar and phosphates in the radiation transport code RITRACKS. These techniques should allow the simulation of DNA damage by ionizing radiation, and understanding of the formation of double-strand breaks caused by clustered damage in different conditions.

From ‘Nerve Fiber Regeneration’ to ‘Functional Changes’ in the Human Brain – On the Paradigm-Shifting Work of the Experimental Physiologist Albrecht Bethe (1872-1954 in Frankfurt am Main

Directory of Open Access Journals (Sweden)

Frank W Stahnisch

2016-02-01

Full Text Available Until the beginning 1930s the traditional dogma that the human central nervous system did not possess any abilities to adapt functionally to degenerative processes and external injuries loomed large in the field of the brain sciences (Hirnforschung. Cutting-edge neuroanatomists, such as the luminary Wilhelm Waldeyer (1836–1921 in Germany or the Nobel Prize laureate Santiago Ramón y Cajal (1852–1934 in Spain, debated any regenerative and thus plastic properties in the human brain. A renewed interest arose in the scientific community to investigate the pathologies and the healing processes in the human central nervous system after the return of the high number of brain injured war veterans from the fronts during and after the First World War (1914–1918. A leading research center in this area was the Institute for the Scientific Study of the Effects of Brain Injuries, which the neurologist Ludwig Edinger (1855–1918 had founded shortly before the war. This article specifically deals with the physiological research on nerve fiber plasticity by Albrecht Bethe (1872–1954 at the respective institute of the University of Frankfurt am Main. Bethe conducted here his paradigmatic experimental studies on the pathophysiological and clinical phenomena of peripheral and central nervous system regeneration.

Moments of the Bethe surface and total inelastic x-ray scattering cross sections for H2

International Nuclear Information System (INIS)

Sharma, B.S.; Thakkar, A.J.

1987-01-01

Moments, S(j,K), of the generalized oscillator strength distribution are global properties of the Bethe surface. Apart from S(-1,K) which is related to the Waller-Hartree incoherent scattering factor, little is known about these moments for nonzero K. This paper describes high-accuracy calculations of S(1,K) and S(2,K) for molecular hydrogen. Comparison with experiment is made, and the utility of simple asymptotic approximations is confirmed. The moments are used to calculate differential cross sections for the inelastic scattering of x rays using the constant-momentum-transfer and constant-angle theories of Bonham. These cross sections differ from the Waller-Hartree cross sections at large angles thus demonstrating the importance of making corrections to the Waller-Hartree theory if the incoherent scattering factor S(K) is to be extracted from experimental inelastic cross sections. Total cross sections for scattering of 6- and 7-keV photons from H 2 are compared with synchrotron radiation scattering experiments. The calculations suggest that the Bonham constant-angle cross sections agree best with experiment. However, further experimental and theoretical work is needed to obtain firm conclusions about the limitations of Waller-Hartree theory

Simple polynomial approximation to modified Bethe formula low-energy electron stopping powers data

Energy Technology Data Exchange (ETDEWEB)

Taborda, A., E-mail: ana.taborda@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Desbrée, A. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Reis, M.A. [C" 2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, EN10 km139.7, 2685-066 Bobadela LRS (Portugal)

2015-08-01

A recently published detailed and exhaustive paper on cross-sections for ionisation induced by keV electrons clearly shows that electron phenomena occurring in parallel with X-ray processes may have been dramatically overlooked for many years, mainly when low atomic number species are involved since, in these cases, the fluorescence coefficient is smaller than the Auger yield. An immediate problem is encountered while attempting to tackle the issue. Accounting for electron phenomena requires the knowledge of the stopping power of electrons within, at least, a reasonably small error. Still, the Bethe formula for stopping powers is known to not be valid for electron energies below 30 keV, and its use leads to values far off experimental ones. Recently, a few authors have addressed this problem and both detailed tables of electron stopping powers for various atomic species and attempts to simplify the calculations, have emerged. Nevertheless, its implementation in software routines to efficiently calculate keV electron effects in materials quickly becomes a bit cumbersome. Following a procedure already used to establish efficient methods to calculate ionisation cross-sections by protons and alpha particles, it became clear that a simple polynomial approximation could be set, which allows retrieving the electronic stopping powers with errors of less than 20% for energies above 500 eV and less than 50% for energies between 50 eV and 500 eV. In this work, we present this approximation which, based on just six parameters, allows to recover electron stopping power values that are less than 20% different from recently published experimentally validated tabulated data.

The critical 1-arm exponent for the ferromagnetic Ising model on the Bethe lattice

Science.gov (United States)

Heydenreich, Markus; Kolesnikov, Leonid

2018-04-01

We consider the ferromagnetic nearest-neighbor Ising model on regular trees (Bethe lattice), which is well-known to undergo a phase transition in the absence of an external magnetic field. The behavior of the model at critical temperature can be described in terms of various critical exponents; one of them is the critical 1-arm exponent ρ which characterizes the rate of decay of the (root) magnetization as a function of the distance to the boundary. The crucial quantity we analyze in this work is the thermal expectation of the root spin on a finite subtree, where the expected value is taken with respect to a probability measure related to the corresponding finite-volume Hamiltonian with a fixed boundary condition. The spontaneous magnetization, which is the limit of this thermal expectation in the distance between the root and the boundary (i.e., in the height of the subtree), is known to vanish at criticality. We are interested in a quantitative analysis of the rate of this convergence in terms of the critical 1-arm exponent ρ. Therefore, we rigorously prove that ⟨σ0⟩ n +, the thermal expectation of the root spin at the critical temperature and in the presence of the positive boundary condition, decays as ⟨σ0 ⟩ n +≈n-1/2 (in a rather sharp sense), where n is the height of the tree. This establishes the 1-arm critical exponent for the Ising model on regular trees (ρ =1/2 ).

Part I: quantum fluctuations in chains of Josephson junctions. Part II: directed aggregation on the Bethe lattice

International Nuclear Information System (INIS)

Bradley, R.M.

1985-01-01

Part I studies the effect of quantum fluctuations of the phase on the low temperature behavior of two models of Josephson junction chains with Coulomb interactions taken into account. The first model, which represents a chain of junctions close to a ground plane, is the Hamiltonian version of the two-dimensional XY model in one space and one time dimension. In the second model, the charging energy for a single junction in the chain is just the parallel-plate capacitor energy. It is shown that quantum fluctuations produce exponential decay of the order parameter correlation junction for any finite value of the junction capacitance. Part II deals with two types of directed aggregation on the Bethe lattice - directed diffusion-limited aggregation DDLA and ballistic aggregation (BA). In the DDLA problem on finite lattices, an exact nonlinear recursion relation is constructed for the probability distribution of the density. The mean density tends to zero as the lattice size is taken into infinity. Using a mapping between the model with perfect adhesion on contact and another model with a particular value of the adhesion probability, it is shown that the adhesion probability is irrelevant over an interval of values

On the degree of ionization in the TFW theory

International Nuclear Information System (INIS)

Baumgartner, B.

1983-01-01

We give a simplified proof of the theorem which says that in Thomas-Fermi-von Weizsaecker theory the surplus charge of bounded electrons cannot exceed the combined charge of the nuclei in absolute value. (Author)

Study of parent-child communication in joint-reading process according the investigation of Beth Ann Beschorner, foreign researcher

Directory of Open Access Journals (Sweden)

Maksimova A.A.

2016-01-01

Full Text Available The article presents the analysis carried out by Ph. D. Beth Ann Beschorner (University of Iowa, USA which concerns the training program for parents aimed at teaching them how to arrange the Dialogic reading with their childrenand and which makes it possible to conclude that due to the experience and direct contact with the written language in preschool age the idea of literacy was being formed. The article compares the empirical data obtained independently in different areas of scientific knowledge, i.e., philosophy and psychology: the study of B.A. Beschorner has a lot in common with the principles of cultural-historical psychology, formulated by L. Vygotsky, M. Lisina and other national psychologists. Although B. A. Beschorner do not stick directly to cultural-historical and activity theory, her results correspond with the basic provisions of these theories. The analysis of B.A. Beschorner’s works confirms the commonality of her findings to those obtained in terms of the cultural-historical theory. It proves that scientific thoughts even going in independent ways, may lead to similar results, which ultimately demonstrates the validity of the findings and the versatility of approaches to the problem

Carl Friedrich von Weizsäcker major texts in physics

CERN Document Server

2014-01-01

This book presents a collection of texts by the German physicist and philosopher Carl Friedrich von Weizsäcker (1912-2007), for use in seminars on the history, epistemology and structure of physics. Most texts appear in English for the first time. Weizsäcker became famous through his works in physics, mainly in the early development of nuclear physics. Later he would also become well known as a philosopher and analyst of contemporary culture. Texts include the original publications of the “Weizsäcker-Bethe formula” of nuclear masses and the “Bethe-Weizsäcker cycle,” which explains the source of energy in the sun; both were developed by Bethe at the same time and independently of Weizsäcker. Further texts deal with Weizsäcker’s explanation of the origin of planets, his explanation of the “time arrow” in Statistical Mechanics and his analyses of Quantum Mechanics and the structure of physics in general.

Changing the Afghan Cycle of Conflict from the Outside, In

Science.gov (United States)

2011-06-01

accountid=12702 (accessed on 05/26/2011). 67 Riedel, Deadly Embrace, 122. 68 Christopher Paul, Colin P. Clarke, and Beth Grill, Victory Has a...2011); and Ian Drury , “Taliban Border between Afghanistan and Pakistan ’is Impossible to Seal’,” Daily Mail, http://www.dailymail.co.uk/news/article...accessed on 04/09/2011). Ollapally, Deepa. The Politics of Extremism in South Asia. Cambridge University Press, 2008. Paul, Christopher, Colin

Mixed spin-3/2 and spin-5/2 Ising system on the Bethe lattice

International Nuclear Information System (INIS)

Albayrak, Erhan; Yigit, Ali

2006-01-01

In order to study the critical behaviors of the half-integer mixed spin-3/2 and spin-5/2 Blume-Capel Ising ferrimagnetic system, we have used the exact recursion relations on the Bethe lattice. The system was studied for the coordination numbers with q=3, 4, 5 and 6, and the obtained phase diagrams are illustrated on the (kT c /|J|,D A /|J|) plane for constant values of D B /|J|, the reduced crystal field of the sublattice with spin-5/2, and on the (kT c /|J|,D B /|J|) plane for constant values of D A /|J|, the reduced crystal field of the sublattice with spin-3/2, for q=3 only, since the cases corresponding to q=4, 5 and 6 reproduce results similar to the case for q=3. In addition we have also presented the phase diagram with equal strengths of the crystal fields for q=3, 4, 5 and 6. Besides the second- and first-order phase transitions, the system also exhibits compensation temperatures for appropriate values of the crystal fields. In this mixed spin system while the second-order phase transition lines never cut the reduced crystal field axes as in the single spin type spin-3/2 and spin-5/2 Ising models separately, the first-order phase transition lines never connect to the second-order phase transition lines and they end at the critical points, therefore the system does not give any tricritical points. In addition to this, this mixed-spin model exhibits one or two compensation temperatures depending on the values of the crystal fields, as a result the compensation temperature lines show reentrant behavior

Approach to calculation of mass spectra and two-photon decays of c c¯ mesons in the framework of Bethe-Salpeter equation

Science.gov (United States)

Bhatnagar, Shashank; Alemu, Lmenew

2018-02-01

In this work we calculate the mass spectra of charmonium for 1 P ,…,4 P states of 0++ and 1++, for 1 S ,…,5 S states of 0-+, and for 1 S ,…,4 D states of 1- along with the two-photon decay widths of the ground and first excited states of 0++ quarkonia for the process O++→γ γ in the framework of a QCD-motivated Bethe-Salpeter equation (BSE). In this 4 ×4 BSE framework, the coupled Salpeter equations are first shown to decouple for the confining part of the interaction (under the heavy-quark approximation) and are analytically solved, and later the one-gluon-exchange interaction is perturbatively incorporated, leading to mass spectral equations for various quarkonia. The analytic forms of wave functions obtained are used for the calculation of the two-photon decay widths of χc 0. Our results are in reasonable agreement with data (where available) and other models.

Nuclear energy of vital importance - or mortal danger

International Nuclear Information System (INIS)

The present booklet contains 3 reports entitled: a) open future of nuclear energy, b) arguments against nuclear power, c) human population needs energy not ideologies. The authors (C.F. v. Weizsaecker, H. Hirsch and W. Schuller) are supporting the utilization of nuclear energy. (RW) [de

Web-based description of the space radiation environment using the Bethe-Bloch model

Science.gov (United States)

Cazzola, Emanuele; Calders, Stijn; Lapenta, Giovanni

2016-01-01

Space weather is a rapidly growing area of research not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary, bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We give a new approach to presenting the topic by developing a web-based application that combines some of the fundamental concepts from these two fields into a single tool that can be used in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to rapidly assess the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions (ACE, GOES-13, GOES-15) to produce a first order approximation of the radiation dose an astronaut would receive during a mission of exploration in deep space (i.e. far from the Earth’s shielding magnetic field and from the radiation belts). DREADCode is based on an easy-to-use GUI interface available online from the European Space Weather Portal (www.spaceweather.eu/dreadcode). The core of the radiation transport computation to produce the radiation dose from the observed fluence of radiation observed by the spacecraft fleet considered is based on a relatively simple approximation: the Bethe-Bloch equation. DREADCode also assumes a simplified geometry and material configuration for the shields used to compute the dose. The approach is approximate and sacrifices some important physics on the altar of rapid execution time, which allows a real-time operation scenario. There is no intention here to produce an operational tool for use in space science and engineering. Rather, we present an educational tool at undergraduate level that uses modern web-based and programming methods to learn some of the most important

Cutting unemployment by a factor of two. Increased use of renewable energies would create 63000 new jobs; Nur noch halb so viele Arbeitslose. Vermehrte Nutzung erneuerbarer Energien wuerde 63000 Arbeitsplaetze schaffen

Energy Technology Data Exchange (ETDEWEB)

Aeberli, O

1999-07-01

In Switzerland, poor energy efficiency costs yearly about 12 billions CHF or 1700 CHF per inhabitant. More news: if renewable energies (solar and wind energy, biomass) would be promoted with concrete targets, job creation balance would result in the positive result of about 63,000 new jobs. These are conclusions from an economic study by Professor Ernst von Weizsaecker, ordered by the association 'Solar 91'. This confirms the energy policy adopted by the Swiss Association of air conditioning companies 'Clima Suisse'. (author) [German] Die mangelnde Energieeffizienz kostet der Schweiz rund 12 Millarden CHF pro Jahr oder 1700 CHF pro Einwohner. Doch damit nicht genug: durch die gezielte Foerderung der erneuerbaren Energien (Sonne, Wind, Biomasse) koennten netto rund 63,000 neue Arbeitsplaetze geschaffen werden. Dies hat eine Wirtschaftsstudie von Professor Ernst von Weizsaecker ergeben, welche die Arbeitsgemeinschaft 'Solar 91' in Auftrag gegeben hat. Der Branchenverband 'Clima Suisse' sieht sich durch diese Studie in seiner Energiepolitik bestaetigt. (author)

The average kinetic energy of the heavy quark in Λb in the Bethe-Salpeter equation approach

International Nuclear Information System (INIS)

Guo, X.-H.; Wu, H.-K.

2007-01-01

In the previous paper, based on the SU(2) f xSU(2) s heavy quark symmetries of the QCD Lagrangian in the heavy quark limit, the Bethe-Salpeter equation for the heavy baryon Λ b was established with the picture that Λ b is composed of a heavy quark and a scalar light diquark. In the present work, we apply this model to calculate μ π 2 for Λ b , the average kinetic energy of the heavy quark inside Λ b . This quantity is particularly interesting since it can be measured in experiments and since it contributes to the inclusive semileptonic decays of Λ b when contributions from higher order terms in 1/M b expansions are taken into account and consequently influences the determination of the Cabibbo-Kobayashi-Maskawa matrix elements V ub and V cb . We find that μ π 2 for Λ b is 0.25GeV 2 ∼0.95GeV 2 , depending on the parameters in the model including the light diquark mass and the interaction strength between the heavy quark and the light diquark in the kernel of the BS equation. We also find that this result is consistent with the value of μ π 2 for Λ b which is derived from the experimental value of μ π 2 for the B meson with the aid of the heavy quark effective theory

Excitonic effects in solids : time-dependent density functional theory versus the Bethe-Salpeter equation

International Nuclear Information System (INIS)

Sagmeister, S.

2009-01-01

The aim of this work is to compare two state-of-the-art methods for the investigation of excitonic effects in solids, namely Time-Dependent Density Functional Theory (TDDFT) and Many-Body Perturbation Theory (MBPT), for selected simple gap systems as well as semiconducting polymers. Within TDDFT, the linear response framework is used and the Dyson equation for the density-density response function is solved, whereas within MBPT, the Bethe-Salpeter equation (BSE) for the electron-hole correlation function is solved. The dielectric function is obtained as a last step. Both techniques take into account the excitonic effects caused by the interaction of electron-hole pairs. In the former these effects are included in the exchange-correlation (xc) kernel, whereas in the latter they are located in the interaction kernel of the BSE. Kohn-Sham single-particle wave functions obtained from Density Functional Theory within the linearized augmented planewave (LAPW) method are used to calculate all relevant quantities of the formalism. For the simple systems GaAs, Si and LiF are chosen. The role of several approximations to the xc kernel is studied and it is found that for GaAs and Si simple semi-empirical models provide a dielectric function in accordance with the BSE. For the case of LiF, being a system with a weak screening and a strongly bound exciton, only an xc kernel derived from MBPT yields reasonable results but still a slight discrepancy to the BSE is observed. Finally, the semiconducting polymers poly-acetylene and poly(phenylene-vinylene) (PPV) are studied. For both materials the concept of semi-empirical approximations to the xc kernel turns out to be ambiguous due to their low-dimensional character. In the case of poly-acetylene, the xc kernel derived from MBPT yields a dielectric function which is in close but not exact agreement with the one obtained from the BSE. (author) [de

Null-plane Bethe-Salpeter dynamics: Mass spectra, decay constants of pseudoscalar mesons, and the pion form factor

International Nuclear Information System (INIS)

Gupta, K.K.; Mitra, A.N.; Singh, N.N.

1990-01-01

A new relativistic definition of the reduced mass (μ 12 ) of a q bar q pair, so as to be in conformity with the standard Wightman-Garding definition of its relative four-momenta q μ , is introduced into the kernel of an ongoing Bethe-Salpeter (BS) program on a two-tier basis. The new definition of μ 12 (involving the hadron mass M) is found to produce a natural Regge asymptotic behavior (M 2 ∼N) in the hadron mass spectra, while retaining the property of an asymptotically linear (∼r) confinement in the three-dimensional structure of the BS kernel. The relativistic structure of μ 12 is responsible for a significant improvement in the fits to the ground-state masses of q bar q and Q bar q mesons as compared to its nonrelativistic definition m 1 m 2 /(m 1 +m 2 ). The leptonic decay constants f p and the charge radii thus calculated are also in excellent agreement with data (π,k) where available, while f p predictions for Q bar q mesons have good overlap with recent lattice predictions. Further, the scaling property (∼k μ -2 ) of the hadron's electromagnetic form factor at large k 2 is a consequence of the ''on-shell'' form of its null-plane wave function. All these results (which are indicated in the barest outline) are preceded by a perspective summary of the theoretical premises and practical working of the BS equation with a four-fermion interaction kernel as a necessary background on a two-tier basis

Magnetic nanoparticles. Metrological aspects

International Nuclear Information System (INIS)

Nikiforov, V N; Nikiforov, A V; Oxengendler, B L; Turaeva, N N; Sredin, V G

2011-01-01

The experiments on influence of the iron oxide cluster size on the specific magnetic moment are performed. Both free and covered clusters are investigated. The experiments are interpreted on the base of core-shell model by analogy to Weizsaecker formula in the nuclear physics. Metrological parameters for the cluster size investigation are obtained.

Wee partons in large nuclei: From virtual dream to hard reality

International Nuclear Information System (INIS)

Venugopalan, R.

1995-01-01

We construct a weak coupling, many body theory to compute parton distributions in large nuclei for x much-lt A - 1/3 . The wee partons are highly coherent, non-Abelian Weizsaecker-Williams fields. Radiative corrections to the classical results axe discussed. The parton distributions for a single nucleus provide the initial conditions for the dynamical evolution of matter formed in ultrarelativistic nuclear collisions

Wee partons in large nuclei: from virtual dream to hard reality

International Nuclear Information System (INIS)

Venugopalan, R.

1995-01-01

We construct a weak coupling, many body theory to compute parton distributions in large nuclei for x -1/3 . The wee partons are highly coherent, non-Abelian Weizsaecker-Williams fields. Radiative corrections to the classical results are discussed. The parton distributions for a single nucleus provide the initial conditions for the dynamical evolution of matter formed in ultrarelativistic nuclear collisions. (orig.)

Coherent π- production in He3 + Li6 → π- + X at 303 MeV/N

International Nuclear Information System (INIS)

Hiller, B.; Pirner, H.J.; Heidelberg Univ.

1982-01-01

The production of pions by the He 3 nucleus is calculated in the Weizsaecker-Williams approximation. The pion cloud of the He 3 nucleus acts like a beam of pions scattering incoherently on the Li 6 nucleus. The size and energy dependence of the observed π-cross section at 0 0 degrees is in good agreement with this theoretical model. (orig.)

Attitude to nuclear energy problems

International Nuclear Information System (INIS)

Danzmann, H.J.

1975-01-01

Two methods are dealt with which show the dialectic shrewdness of some of the active nuclear energy opponents in their attempt to influence opinions. By means of examples of quotations from lectures of recognized scientists (v. Weizsaecker, Teller, Heisenberg, Winnacker) which are torn out of their context, the public are deliberately misled by a few demagogic nuclear power critics. (HP/LH) [de

Bethe-Salpeter wave functions of ηc(1S, 2S) and ψ(1S, 2S) states: local-potential description of the charmonium system revisited

Science.gov (United States)

Nochi, Kazuki; Kawanai, Taichi; Sasaki, Shoichi

2018-03-01

The quark potential models with an energy-independent central potential have been successful for understanding the conventional charmonium states especially below the open charm threshold. As one might consider, however, the interquark potential is in general energy-dependent, and its tendency gets stronger in higher lying states. Confirmation of whether the interquark potential is energy-independent is also important to verify the validity of the quark potential models. In this talk, we examine the energy dependence of the charmonium potential, which can be determined from the Bethe-Salpeter (BS) amplitudes of cc̅ mesons in lattice QCD.We first calculate the BS amplitudes of radially excited charmonium states, the ηc(2S) and ψ(2S) states, using the variational method and then determine both the quark kinetic mass and the charmonium potential within the HAL QCD method. Through a direct comparison of charmonium potentials determined from both the 1S and 2S states, we confirm that neither the central nor spin-spin potential shows visible energy dependence at least up to 2S state.

Bipolar mood cycles and lunar tidal cycles.

Science.gov (United States)

Wehr, T A

2018-04-01

In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon's semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies ('supermoons'). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles' being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon's semi-diurnal gravimetric tides might have driven the patients' bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker's phase-relationship to sleep in a manner that is known to cause switches from depression to mania.

63000 new jobs thanks to renewable energy in Switzerland; Dreiundsechzigtausend Arbeitsplaetze dank erneuerbaren Energien

Energy Technology Data Exchange (ETDEWEB)

Stricker, B

1999-07-01

This is a short report on the recent study by the Wuppertaler Institute (Executive Director: Prof. Dr. Ernst U. von Weizsaecker) under a mandate from the Swiss Working Group 'Solar 91' with the support of the Swiss Federal Office of Energy. The conclusion is that energy efficiency and a broad market penetration of renewable energy sources would reduce unemployment in Switzerland by a factor of 2 and create at least 63,000 new jobs. Background for the publication of this report at the end of August 1999 was the Swiss parliament debate on new energy tax regulations to be submitted to the poles in the course of 2000. The two houses of the parliament had different opinions on the matter. [German] Eine Studie des Wuppertaler Institutes (unter der Leitung von Prof. Dr. Ernst U. von Weizsaecker) im Auftrag der Schweizerischen Arbeitsgemeinschaft 'Solar 91' und vom Bundesamt fuer Energie finanziell unterstuetzt, kommt zum Schluss, dass Energieeffizienz und eine breite Einfuehrung der erneuerbaren Energien die Arbeitslosigkeit halbieren und mindestens 63,000 neue Arbeitsstellen schaffen wuerde. Hintergrund der Publikation dieser Studie Ende August 1999 war die Differenzbereinigung der Solar- und der Energie/Umweltinitiative im Parlament. (author)

Photoproduction of jets at HERA

International Nuclear Information System (INIS)

Chyla, J.

1993-01-01

The intimate relation between the direct and resolved photon interactions, due to the factorization mechanism, is elucidated. It is argued that recent data from HERA do not provide a direct evidence for the latter component, but should rather be interpreted as a manifestation of the O(α s 2 ) term in γp and, via the Weizsaecker-Williams approximation, in ep interactions. 5 figs., 12 refs

The Krebs Uric Acid Cycle: A Forgotten Krebs Cycle.

Science.gov (United States)

Salway, Jack G

2018-05-25

Hans Kornberg wrote a paper entitled 'Krebs and his trinity of cycles' commenting that every school biology student knows of the Krebs cycle, but few know that Krebs discovered two other cycles. These are (i) the ornithine cycle (urea cycle), (ii) the citric acid cycle (tricarboxylic acid or TCA cycle), and (iii) the glyoxylate cycle that was described by Krebs and Kornberg. Ironically, Kornberg, codiscoverer of the 'glyoxylate cycle', overlooked a fourth Krebs cycle - (iv) the uric acid cycle. Copyright © 2018 Elsevier Ltd. All rights reserved.

Discrete geometric analysis of message passing algorithm on graphs

Science.gov (United States)

Watanabe, Yusuke

2010-04-01

We often encounter probability distributions given as unnormalized products of non-negative functions. The factorization structures are represented by hypergraphs called factor graphs. Such distributions appear in various fields, including statistics, artificial intelligence, statistical physics, error correcting codes, etc. Given such a distribution, computations of marginal distributions and the normalization constant are often required. However, they are computationally intractable because of their computational costs. One successful approximation method is Loopy Belief Propagation (LBP) algorithm. The focus of this thesis is an analysis of the LBP algorithm. If the factor graph is a tree, i.e. having no cycle, the algorithm gives the exact quantities. If the factor graph has cycles, however, the LBP algorithm does not give exact results and possibly exhibits oscillatory and non-convergent behaviors. The thematic question of this thesis is "How the behaviors of the LBP algorithm are affected by the discrete geometry of the factor graph?" The primary contribution of this thesis is the discovery of a formula that establishes the relation between the LBP, the Bethe free energy and the graph zeta function. This formula provides new techniques for analysis of the LBP algorithm, connecting properties of the graph and of the LBP and the Bethe free energy. We demonstrate applications of the techniques to several problems including (non) convexity of the Bethe free energy, the uniqueness and stability of the LBP fixed point. We also discuss the loop series initiated by Chertkov and Chernyak. The loop series is a subgraph expansion of the normalization constant, or partition function, and reflects the graph geometry. We investigate theoretical natures of the series. Moreover, we show a partial connection between the loop series and the graph zeta function.

Alternative ORC bottoming cycles FOR combined cycle power plants

International Nuclear Information System (INIS)

Chacartegui, R.; Sanchez, D.; Munoz, J.M.; Sanchez, T.

2009-01-01

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

Cycling infrastructure for reducing cycling injuries in cyclists.

Science.gov (United States)

Mulvaney, Caroline A; Smith, Sherie; Watson, Michael C; Parkin, John; Coupland, Carol; Miller, Philip; Kendrick, Denise; McClintock, Hugh

2015-12-10

Cycling is an attractive form of transport. It is beneficial to the individual as a form of physical activity that may fit more readily into an individual's daily routine, such as for cycling to work and to the shops, than other physical activities such as visiting a gym. Cycling is also beneficial to the wider community and the environment as a result of fewer motorised journeys. Cyclists are seen as vulnerable road users who are frequently in close proximity to larger and faster motorised vehicles. Cycling infrastructure aims to make cycling both more convenient and safer for cyclists. This review is needed to guide transport planning. To:1. evaluate the effects of different types of cycling infrastructure on reducing cycling injuries in cyclists, by type of infrastructure;2. evaluate the effects of cycling infrastructure on reducing the severity of cycling injuries in cyclists;3. evaluate the effects of cycling infrastructure on reducing cycling injuries in cyclists with respect to age, sex and social group. We ran the most recent search on 2nd March 2015. We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (OvidSP), Embase Classic + Embase(OvidSP), PubMed and 10 other databases. We searched websites, handsearched conference proceedings, screened reference lists of included studies and previously published reviews and contacted relevant organisations. We included randomised controlled trials, cluster randomised controlled trials, controlled before-after studies, and interrupted time series studies which evaluated the effect of cycling infrastructure (such as cycle lanes, tracks or paths, speed management, roundabout design) on cyclist injury or collision rates. Studies had to include a comparator, that is, either no infrastructure or a different type of infrastructure. We excluded studies that assessed collisions that occurred as a result of competitive cycling. Two review authors examined the titles and

Optimum gas turbine cycle for combined cycle power plant

International Nuclear Information System (INIS)

Polyzakis, A.L.; Koroneos, C.; Xydis, G.

2008-01-01

The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power

From quantum physics to consciousness. Cosmos, spirit, and matter; Von der Quantenphysik zum Bewusstsein. Kosmos, Geist und Materie

Energy Technology Data Exchange (ETDEWEB)

Goernitz, Thomas [Frankfurt Univ., Frankfurt am Main (Germany). Fachbereich Physik; Goernitz, Brigitte

2016-07-01

The present book is a consequent continuation and deepening of a new concept layed down ba Thomas and Brigitte Goernitz in several writings. Starting from quantum theory they describe the evolution of the spirituality from the origin of the cosmos until the origin of the consciousness. Obtained was this knowledge by profund physical and mathematical research lasting for decades and in cooperation lasting for years with scientists and philosophers, especially with Carl Friedrich v. Weizsaecker.

Nuclear problems 1983: Renormalization of a stagnating market

International Nuclear Information System (INIS)

Anon.

1983-01-01

The 1983 Annual Meeting on Nuclear Engineering was held by Deutsches Atomforum (DAtF) and Kerntechnische Gesellschaft (KTG) in Berlin on June 14 to 16, 1983. The article presents parts of the opening speeches of H. Hennies, chairman of the meeting, and R. von Weizsaecker, mayor in office of Berlin, the closing speech of R. Guck, chairman of Deutsches Atomforum, and the speech of H. Riesenhuber, Federal Minister for Research and Technology. (orig.) [de

From quantum physics to consciousness. Cosmos, spirit, and matter

International Nuclear Information System (INIS)

Goernitz, Thomas; Goernitz, Brigitte

2016-01-01

The present book is a consequent continuation and deepening of a new concept layed down ba Thomas and Brigitte Goernitz in several writings. Starting from quantum theory they describe the evolution of the spirituality from the origin of the cosmos until the origin of the consciousness. Obtained was this knowledge by profund physical and mathematical research lasting for decades and in cooperation lasting for years with scientists and philosophers, especially with Carl Friedrich v. Weizsaecker.

Cycles and Common Cycles in Property and Related Sectors

OpenAIRE

Peijie Wang

2003-01-01

This paper examines cycles and common cycles in the property market and the economy. While focusing on common cycles, the study also incorporates common trends in the meantime, so it covers the whole spectrum of dynamic analysis. It has been found that property shares common cycles, particularly with those sectors that are the user markets of property. The mechanisms of common cycles and the relative magnitudes of cycles of the sectors related to property are discussed to shed light on proper...

HCl removal using cycled carbide slag from calcium looping cycles

International Nuclear Information System (INIS)

Xie, Xin; Li, Yingjie; Wang, Wenjing; Shi, Lei

2014-01-01

Highlights: • Cycled carbide slag from calcium looping cycles is used to remove HCl. • The optimum temperature for HCl removal of cycled carbide slag is 700 °C. • The presence of CO 2 restrains HCl removal of cycled carbide slag. • CO 2 capture conditions have important effects on HCl removal of cycled carbide slag. • HCl removal capacity of carbide slag drops with cycle number rising from 1 to 50. - Abstract: The carbide slag is an industrial waste from chlor-alkali plants, which can be used to capture CO 2 in the calcium looping cycles, i.e. carbonation/calcination cycles. In this work, the cycled carbide slag from the calcium looping cycles for CO 2 capture was proposed to remove HCl in the flue gas from the biomass-fired and RDFs-fired boilers. The effects of chlorination temperature, HCl concentration, particle size, presence of CO 2 , presence of O 2 , cycle number and CO 2 capture conditions in calcium looping cycles on the HCl removal behavior of the carbide slag experienced carbonation/calcination cycles were investigated in a triple fixed-bed reactor. The chlorination product of the cycled carbide slag from the calcium looping after absorbing HCl is not CaCl 2 but CaClOH. The optimum temperature for HCl removal of the cycled carbide slag from the carbonation/calcination cycles is 700 °C. The chlorination conversion of the cycled carbide slag increases with increasing the HCl concentration. The cycled carbide slag with larger particle size exhibits a lower chlorination conversion. The presence of CO 2 decreases the chlorination conversions of the cycled carbide slag and the presence of O 2 has a trifling impact. The chlorination conversion of the carbide slag experienced 1 carbonation/calcination cycle is higher than that of the uncycled calcined sorbent. As the number of carbonation/calcination cycles increases from 1 to 50, the chlorination conversion of carbide slag drops gradually. The high calcination temperature and high CO 2

Will Solar Cycles 25 and 26 Be Weaker than Cycle 24?

Science.gov (United States)

Javaraiah, J.

2017-11-01

The study of variations in solar activity is important for understanding the underlying mechanism of solar activity and for predicting the level of activity in view of the activity impact on space weather and global climate. Here we have used the amplitudes (the peak values of the 13-month smoothed international sunspot number) of Solar Cycles 1 - 24 to predict the relative amplitudes of the solar cycles during the rising phase of the upcoming Gleissberg cycle. We fitted a cosine function to the amplitudes and times of the solar cycles after subtracting a linear fit of the amplitudes. The best cosine fit shows overall properties (periods, maxima, minima, etc.) of Gleissberg cycles, but with large uncertainties. We obtain a pattern of the rising phase of the upcoming Gleissberg cycle, but there is considerable ambiguity. Using the epochs of violations of the Gnevyshev-Ohl rule (G-O rule) and the `tentative inverse G-O rule' of solar cycles during the period 1610 - 2015, and also using the epochs where the orbital angular momentum of the Sun is steeply decreased during the period 1600 - 2099, we infer that Solar Cycle 25 will be weaker than Cycle 24. Cycles 25 and 26 will have almost same strength, and their epochs are at the minimum between the current and upcoming Gleissberg cycles. In addition, Cycle 27 is expected to be stronger than Cycle 26 and weaker than Cycle 28, and Cycle 29 is expected to be stronger than both Cycles 28 and 30. The maximum of Cycle 29 is expected to represent the next Gleissberg maximum. Our analysis also suggests a much lower value (30 - 40) for the maximum amplitude of the upcoming Cycle 25.

Culture in cycles: considering H.T. Odum's 'information cycle'

Science.gov (United States)

Abel, Thomas

2014-01-01

'Culture' remains a conundrum in anthropology. When recast in the mold of 'information cycles,' culture is transformed. New fault lines appear. Information is splintered into parallel or nested forms. Dynamics becomes cycling. Energy is essential. And culture has function in a directional universe. The 'information cycle' is the crowning component of H.T. Odum's theory of general systems. What follows is an application of the information cycle to the cultural domains of discourse, social media, ritual, education, journalism, technology, academia, and law, which were never attempted by Odum. In information cycles, cultural information is perpetuated - maintained against Second Law depreciation. Conclusions are that culture is in fact a nested hierarchy of cultural forms. Each scale of information production is semi-autonomous, with its own evolutionary dynamics of production and selection in an information cycle. Simultaneously, each information cycle is channeled or entrained by its larger scale of information and ultimately human-ecosystem structuring.

Connections of the Liouville model and XXZ spin chain

Science.gov (United States)

Faddeev, Ludvig D.; Tirkkonen, Olav

1995-02-01

The quantum theory of the Liouville model with imaginary field is considered using the Quantum Inverse Scattering Method. An integrable structure with non-trivial spectral-parameter dependence is developed for lattice Liouville theory by scaling the L-matrix of lattice sine-Gordon theory. This L-matrix yields Bethe ansatz equations for Liouville theory, by the methods of the algebraic Bethe ansatz. Using the string picture of excited Bethe states, the lattice Liouville Bethe equations are mapped to the corresponding spin- {1}/{2} XXZ chain equations. The well developed theory of finite-size corrections in spin chains is used to deduce the conformal properties of the lattice Liouville Bethe states. The unitary series of conformal field theories emerge for Liouville couplings of the form γ = πν/( ν + 1), corresponding to root of unity XXZ anisotropies. The Bethe states give the full spectrum of the corresponding unitary conformal field theory, with the primary states in the Kač table parameterized by a string length K, and the remnant of the chain length mod ( ν + 1).

Connections of the Liouville model and XXZ spin chain

International Nuclear Information System (INIS)

Faddeev, L.D.; Tirkkonen, O.

1995-01-01

The quantum theory of the Liouville model with imaginary field is considered using the Quantum Inverse Scattering Method. An integrable structure with non-trivial spectral-parameter dependence is developed for lattice Liouville theory by scaling the L-matrix of lattice sine-Gordon theory. This L-matrix yields Bethe ansatz equations for Liouville theory, by the methods of the algebraic Bethe ansatz. Using the string picture of excited Bethe states, the lattice Liouville Bethe equations are mapped to the corresponding spin-1/2 XXZ chain equations. The well developed theory of finite-size corrections in spin chains is used to deduce the conformal properties of the lattice Liouville Bethe states. The unitary series of conformal field theories emerge for Liouville couplings of the form γ= πν/(ν+1), corresponding to root of unity XXZ anisotropies. The Bethe states give the full spectrum of the corresponding unitary conformal field theory, with the primary states in the Kac table parameterized by a string length K, and the remnant of the chain length mod (ν+1). (orig.)

Proliferation in cycle

Energy Technology Data Exchange (ETDEWEB)

Piao Yunsong [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: yspiao@gucas.ac.cn

2009-06-15

In the contracting phase with w{approx_equal}0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w{approx_equal}0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

Proliferation in cycle

International Nuclear Information System (INIS)

Piao Yunsong

2009-01-01

In the contracting phase with w≅0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w≅0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

Energy Technology Data Exchange (ETDEWEB)

Hilger, Thomas Uwe

2012-04-11

The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Your Menstrual Cycle

Science.gov (United States)

... your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... that take place over the weeks in your cycle. Want to know what happens on each day ...

Fuel cycle cost uncertainty from nuclear fuel cycle comparison

International Nuclear Information System (INIS)

Li, J.; McNelis, D.; Yim, M.S.

2013-01-01

This paper examined the uncertainty in fuel cycle cost (FCC) calculation by considering both model and parameter uncertainty. Four different fuel cycle options were compared in the analysis including the once-through cycle (OT), the DUPIC cycle, the MOX cycle and a closed fuel cycle with fast reactors (FR). The model uncertainty was addressed by using three different FCC modeling approaches with and without the time value of money consideration. The relative ratios of FCC in comparison to OT did not change much by using different modeling approaches. This observation was consistent with the results of the sensitivity study for the discount rate. Two different sets of data with uncertainty range of unit costs were used to address the parameter uncertainty of the FCC calculation. The sensitivity study showed that the dominating contributor to the total variance of FCC is the uranium price. In general, the FCC of OT was found to be the lowest followed by FR, MOX, and DUPIC. But depending on the uranium price, the FR cycle was found to have lower FCC over OT. The reprocessing cost was also found to have a major impact on FCC

Cutting unemployment by a factor of two. Increased use of renewable energies would create 63000 new jobs

International Nuclear Information System (INIS)

Aeberli, O.

1999-01-01

In Switzerland, poor energy efficiency costs yearly about 12 billions CHF or 1700 CHF per inhabitant. More news: if renewable energies (solar and wind energy, biomass) would be promoted with concrete targets, job creation balance would result in the positive result of about 63,000 new jobs. These are conclusions from an economic study by Professor Ernst von Weizsaecker, ordered by the association 'Solar 91'. This confirms the energy policy adopted by the Swiss Association of air conditioning companies 'Clima Suisse'. (author) [de

DETECTING ALIEN LIMIT CYCLES NEAR A HAMILTONIAN 2-SADDLE CYCLE

OpenAIRE

LUCA, Stijn; DUMORTIER, Freddy; Caubergh, M.; Roussarie, R.

2009-01-01

This paper aims at providing and example of a cubic Hamiltonian 2-saddle cycle that after bifurcation can give rise to an alien limit cycle; this is a limit cycle that is not controlled by a zero of the related Abelian integral. To guarantee the existence of an alien limit cycle one can verify generic conditions on the Abelian integral and on the transition map associated to the connections of the 2-saddle cycle. In this paper, a general method is developed to compute the first and second der...

Proposal of a nuclear cycle research and development plan in Tokai works. The roadmap from LWR cycle to FBR cycle

International Nuclear Information System (INIS)

Nakamura, Hirofumi; Abe, Tomoyuki; Kashimura, Takuo; Nagai, Toshihisa; Maeda, Seichiro; Yamaguchi, Toshiya; Kuroki, Ryoichiro

2003-07-01

The Generation-II Project Task Force Team has investigated a research and development plan of a future nuclear fuel cycle in Tokai works for about three months from December 19, 2002. First we have discussed about the present condition of Japanese nuclear fuel cycle and have recognized it as the following. The relation of the technology between the LWR-cycle and the FBR-cycle is not clear. MOX Fuel Use in Light Water Reactors is important to establish technology of the FBR fuel cycle. Radioactive waste disposal issue is urgent. Next we have proposed the three basic policies on R and D plan of nuclear fuel cycle in consideration of the F.S. on FBR-cycle. Establishment and advancement of 'the tough nuclear fuel cycle'. Early establishment of the FBR cycle technology to be able to supply energy stably for long-term. Establishment of the radioactive waste treatment and disposal technology, and optimization of nuclear fuel cycle technology from the viewpoint of radioactive waste. And we have proposed the Japanese technical holder system to integrate all LWR and FBR cycle technology. (author)

Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

KAUST Repository

Jaasim, Mohammed

2017-03-13

Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities, such as the indicated mean effective pressure (IMEP) are observed at different levels. Accurate prediction of CCV in IC engines is an important but challenging task. Computational fluid dynamics (CFD) simulations using high performance computing (HPC) can be used effectively to visualize such 3D spatial distributions. In the present study, a dual fuel large engine is considered, with natural gas injected into the manifold accompanied with direct injection of diesel pilot fuel to trigger ignition. Multiple engine cycles in 3D are simulated in series as in the experiments to investigate the potential of HPC based high fidelity simulations to accurately capture the cycle to cycle variation in dual fuel engines. Open cycle simulations are conducted to predict the combined effect of the stratification of fuel-air mixture, temperature and turbulence on the CCV of pressure. The predicted coefficient of variation (COV) of pressure compared to the results from closed cycle simulations and the experiments.

Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

KAUST Repository

Jaasim, Mohammed; Pasunurthi, Shyamsundar; Jupudi, Ravichandra S.; Gubba, Sreenivasa Rao; Primus, Roy; Klingbeil, Adam; Wijeyakulasuriya, Sameera; Im, Hong G.

2017-01-01

Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities

Life-cycle cost analysis of adsorption cycles for desalination

KAUST Repository

Thu, Kyaw

2010-08-01

This paper presents the thermo-economic analysis of the adsorption desalination (AD) cycle that is driven by low-temperature waste heat from exhaust of industrial processes or renewable sources. The AD cycle uses an adsorbent such as the silica gel to desalt the sea or brackish water. Based on an experimental prototype AD plant, the life-cycle cost analysis of AD plants of assorted water production capacities has been simulated and these predictions are translated into unit cost of water production. Our results show that the specific energy consumption of the AD cycle is 1.38 kWh/m3 which is the lowest ever reported. For a plant capacity of 1000 m3/d, the AD cycle offers a unit cost of $0.457/m3 as compared to more than $0.9 for the average RO plants. Besides being cost-effective, the AD cycle is also environment-friendly as it emits less CO2 emission per m3 generated, typically 85% less, by comparison to an RO process. © 2010 Desalination Publications.

How well can business cycle accounting account for business cycles?

OpenAIRE

Keisuke Otsu

2012-01-01

The business cycle accounting method introduced by Chari, Kehoe and McGrattan (2007) is a useful tool to decompose business cycle fluctuations into their contributing factors. However, the model estimated by the maximum likelihood method cannot replicate business cycle moments computed from data. Moment-based estimation might be an attractive alternative if the purpose of the research is to study business cycle properties such as volatility, persistence and cross-correlation of variables inst...

Cycling in Sydney, Australia

Directory of Open Access Journals (Sweden)

Alexis Zander

2013-01-01

Full Text Available Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants’ confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

Marine nitrogen cycle

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.

) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

Reproductive cycles in tropical intertidal gastropods are timed around tidal amplitude cycles.

Science.gov (United States)

Collin, Rachel; Kerr, Kecia; Contolini, Gina; Ochoa, Isis

2017-08-01

Reproduction in iteroparous marine organisms is often timed with abiotic cycles and may follow lunar, tidal amplitude, or daily cycles. Among intertidal marine invertebrates, decapods are well known to time larval release to coincide with large amplitude nighttime tides, which minimizes the risk of predation. Such bimonthly cycles have been reported for few other intertidal invertebrates. We documented the reproduction of 6 gastropod species from Panama to determine whether they demonstrate reproductive cycles, whether these cycles follow a 2-week cycle, and whether cycles are timed so that larval release occurs during large amplitude tides. Two of the species ( Crepidula cf. marginalis and Nerita scabricosta ) showed nonuniform reproduction, but without clear peaks in timing relative to tidal or lunar cycles. The other 4 species show clear peaks in reproduction occurring every 2 weeks. In 3 of these species ( Cerithideopsis carlifornica var. valida, Littoraria variegata , and Natica chemnitzi ), hatching occurred within 4 days of the maximum amplitude tides. Siphonaria palmata exhibit strong cycles, but reproduction occurred during the neap tides. Strong differences in the intensity of reproduction of Cerithideopsis carlifornica , and in particular, Littoraria variegata , between the larger and smaller spring tides of a lunar month indicate that these species time reproduction with the tidal amplitude cycle rather than the lunar cycle. For those species that reproduce during both the wet and dry seasons, we found that reproductive timing did not differ between seasons despite strong differences in temperature and precipitation. Overall, we found that most (4/6) species have strong reproductive cycles synchronized with the tidal amplitude cycle and that seasonal differences in abiotic factors do not alter these cycles.

Creeping of hysteresis cycles; Reptation des cycles d'hysteresis

Energy Technology Data Exchange (ETDEWEB)

Neel, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de Grenoble, 38 (France)

1959-07-01

Creeping consists of a kind of progressive translation of dissymmetric ferromagnetic hysteresis cycles as a function of the order number of the cycle. It is interpreted here by means of a probable coupling field, the existence of which is connected to a statistical conception of the distribution of the elementary regions. (author) [French] La reptation consiste en une sorte de translation progressive des cycles d'hysteresis ferromagnetiques dissymetriques en fonction du numero d'ordre du cycle. L'auteur l'interprete au moyen d'un champ aleatoire de couplage dont l'existence est liee a une conception statistique de la distribution des domaines elementaires. (auteur)

Glacial cycles

DEFF Research Database (Denmark)

Kaufmann, R. K.; Juselius, Katarina

We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...... and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed...... to simulate glacial cycles accurately. Also, results suggest that non-linear 10 dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles....

ThyssenKrupp magazine - Environment; ThyssenKrupp Magazin - Umwelt

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-01-15

The magazine covers the following topics: The view of E.-U. Weizsaecker concerning environment; a discussion on climatic change and changes of consciousness; the right measures against environmental problems; on happiness of mankind; the CO{sub 2} problem; environmentally friendly knowledge transfer; sustainable investment; cultural translation; wind power; mobility; lifestyle changes due to the demographic development; several generation under one roof; natural catastrophies; adaptation strategies in the context of natural catastrophies; mankind-induced changes; burnout - a symptom of the high perfomance society; the planet of nomads.

Systematic study of shell effect near drip-lines

International Nuclear Information System (INIS)

Adhikari, S.; Samanta, C.

2004-01-01

The variation of nuclear shell effects with nucleon numbers is evaluated using the modified Bethe–Weizsaecker mass formula (BWM) and the measured atomic masses. The shell effects at magic neutron numbers N=8, 20, 28, 50, 82 and 126 and magic proton numbers Z=8, 20, 28, 50 and 82 are found to vary rapidly approaching the drip-lines. The shell effect due to one magic number increases on approaching another magic number. Thus, shell effects are not always negligible near the drip-lines. (author)

The glutathione cycle: Glutathione metabolism beyond the γ-glutamyl cycle.

Science.gov (United States)

Bachhawat, Anand Kumar; Yadav, Shambhu

2018-04-17

Glutathione was discovered in 1888, over 125 years ago. Since then, our understanding of various functions and metabolism of this important molecule has grown over these years. But it is only now, in the last decade, that a somewhat complete picture of its metabolism has emerged. Glutathione metabolism has till now been largely depicted and understood by the γ-glutamyl cycle that was proposed in 1970. However, new findings and knowledge particularly on the transport and degradation of glutathione have revealed that many aspects of the γ-glutamyl cycle are incorrect. Despite this, an integrated critical analysis of the cycle has never been undertaken and this has led to the cycle and its errors perpetuating in the literature. This review takes a careful look at the γ-glutamyl cycle and its shortcomings and presents a "glutathione cycle" that captures the current understanding of glutathione metabolism. © 2018 IUBMB Life, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

Single generation cycles and delayed feedback cycles are not separate phenomena.

Science.gov (United States)

Pfaff, T; Brechtel, A; Drossel, B; Guill, C

2014-12-01

We study a simple model for generation cycles, which are oscillations with a period of one or a few generation times of the species. The model is formulated in terms of a single delay-differential equation for the population density of an adult stage, with recruitment to the adult stage depending on the intensity of competition during the juvenile phase. This model is a simplified version of a group of models proposed by Gurney and Nisbet, who were the first to distinguish between single-generation cycles and delayed-feedback cycles. According to these authors, the two oscillation types are caused by different mechanisms and have periods in different intervals, which are one to two generation times for single-generation cycles and two to four generation times for delayed-feedback cycles. By abolishing the strict coupling between the maturation time and the time delay between competition and its effect on the population dynamics, we find that single-generation cycles and delayed-feedback cycles occur in the same model version, with a gradual transition between the two as the model parameters are varied over a sufficiently large range. Furthermore, cycle periods are not bounded to lie within single octaves. This implies that a clear distinction between different types of generation cycles is not possible. Cycles of all periods and even chaos can be generated by varying the parameters that determine the time during which individuals from different cohorts compete with each other. This suggests that life-cycle features in the juvenile stage and during the transition to the adult stage are important determinants of the dynamics of density limited populations. Copyright © 2014 Elsevier Inc. All rights reserved.

[Cycling in Zagreb].

Science.gov (United States)

Matos, Stipan; Krapac, Ladislav; Krapac, Josip

2007-01-01

Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

Exact solution of the one-dimensional Hubbard model with arbitrary boundary magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Li, Yuan-Yuan; Cao, Junpeng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Wen-Li [Institute of Modern Physics, Northwest University, Xian 710069 (China); Beijing Center for Mathematics and Information Interdisciplinary Sciences, Beijing, 100048 (China); Shi, Kangjie [Institute of Modern Physics, Northwest University, Xian 710069 (China); Wang, Yupeng, E-mail: yupeng@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-02-15

The one-dimensional Hubbard model with arbitrary boundary magnetic fields is solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz in the charge sector, the second eigenvalue problem associated with the spin sector is constructed. It is shown that the second eigenvalue problem can be transformed into that of the inhomogeneous XXX spin chain with arbitrary boundary fields which can be solved via the off-diagonal Bethe ansatz method.

Cycle to Cycle Variation Study in a Dual Fuel Operated Engine

KAUST Repository

Pasunurthi, Shyamsundar

2017-03-28

The standard capability of engine experimental studies is that ensemble averaged quantities like in-cylinder pressure from multiple cycles and emissions are reported and the cycle to cycle variation (CCV) of indicated mean effective pressure (IMEP) is captured from many consecutive combustion cycles for each test condition. However, obtaining 3D spatial distribution of all the relevant quantities such as fuel-air mixing, temperature, turbulence levels and emissions from such experiments is a challenging task. Computational Fluid Dynamics (CFD) simulations of engine flow and combustion can be used effectively to visualize such 3D spatial distributions. A dual fuel engine is considered in the current study, with manifold injected natural gas (NG) and direct injected diesel pilot for ignition. Multiple engine cycles in 3D are simulated in series like in the experiments to investigate the potential of high fidelity RANS simulations coupled with detailed chemistry, to accurately predict the CCV. Cycle to cycle variation (CCV) is expected to be due to variabilities in operating and boundary conditions, in-cylinder stratification of diesel and natural gas fuels, variation in in-cylinder turbulence levels and velocity flow-fields. In a previous publication by the authors [1], variabilities in operating and boundary conditions are incorporated into several closed cycle simulations performed in parallel. Stochastic variations/stratifications of fuel-air mixture, turbulence levels, temperature and internal combustion residuals cannot be considered in such closed cycle simulations. In this study, open cycle simulations with port injection of natural gas predicted the combined effect of the stratifications on the CCV of in-cylinder pressure. The predicted Coefficient of Variation (COV) of cylinder pressure is improved compared to the one captured by closed cycle simulations in parallel.

Internal cycle modeling and environmental assessment of multiple cycle consumer products

International Nuclear Information System (INIS)

Tsiliyannis, C.A.

2012-01-01

Highlights: ► Dynamic flow models are presented for remanufactured, reused or recycled products. ► Early loss and stochastic return are included for fast and slow cycling products. ► The reuse-to-input flow ratio (Internal Cycle Factor, ICF) is determined. ► The cycle rate, which is increasing with the ICF, monitors eco-performance. ► Early internal cycle losses diminish the ICF, the cycle rate and performance. - Abstract: Dynamic annual flow models incorporating consumer discard and usage loss and featuring deterministic and stochastic end-of-cycle (EOC) return by the consumer are developed for reused or remanufactured products (multiple cycle products, MCPs), including fast and slow cycling, short and long-lived products. It is shown that internal flows (reuse and overall consumption) increase proportionally to the dimensionless internal cycle factor (ICF) which is related to environmental impact reduction factors. The combined reuse/recycle (or cycle) rate is shown capable for shortcut, albeit effective, monitoring of environmental performance in terms of waste production, virgin material extraction and manufacturing impacts of all MCPs, a task, which physical variables (lifetime, cycling frequency, mean or total number of return trips) and conventional rates, via which environmental policy has been officially implemented (e.g. recycling rate) cannot accomplish. The cycle rate is shown to be an increasing (hyperbolic) function of ICF. The impact of the stochastic EOC return characteristics on total reuse and consumption flows, as well as on eco-performance, is assessed: symmetric EOC return has a small, positive effect on performance compared to deterministic, while early shifted EOC return is more beneficial. In order to be efficient, environmental policy should set higher minimum reuse targets for higher trippage MCPs. The results may serve for monitoring, flow accounting and comparative eco-assessment of MCPs. They may be useful in identifying

Cycle to Cycle Variation Study in a Dual Fuel Operated Engine

KAUST Repository

Pasunurthi, Shyamsundar; Jupudi, Ravichandra; Wijeyakulasuriya, Sameera; Gubba, Sreenivasa Rao; Im, Hong G.; Jaasim, Mohammed; Primus, Roy; Klingbeil, Adam; Finney, Charles

2017-01-01

The standard capability of engine experimental studies is that ensemble averaged quantities like in-cylinder pressure from multiple cycles and emissions are reported and the cycle to cycle variation (CCV) of indicated mean effective pressure (IMEP

The Hamburg oceanic carbon cycle circulation model. Cycle 1

International Nuclear Information System (INIS)

Maier-Reimer, E.; Heinze, C.

1992-02-01

The carbon cycle model calculates the prognostic fields of oceanic geochemical carbon cycle tracers making use of a 'frozen' velocity field provided by a run of the LSG oceanic circulation model (see the corresponding manual, LSG=Large Scale Geostrophic). The carbon cycle model includes a crude approximation of interactions between sediment and bottom layer water. A simple (meridionally diffusive) one layer atmosphere model allows to calculate the CO 2 airborne fraction resulting from the oceanic biogeochemical interactions. (orig.)

Future fuel cycles

International Nuclear Information System (INIS)

Archinoff, G.H.

1980-01-01

A fuel cycle must offer both financial and resource savings if it is to be considered for introduction into Ontario's nuclear system. The most promising alternative CANDU fuel cycles are examined in the context of both of these factors over a wide range of installed capacity growth rates and economic assumptions, in order to determine which fuel cycle, or cycles, should be introduced, and when. It is concluded that the optimum path for the long term begins with the prompt introduction of the low-enriched-uranium fuel cycle. For a wide range of conditions, this cycle remains the optimum throughout the very long term. Conditions of rapid nuclear growth and very high uranium price escalation rates warrant the supersedure of the low-enriched-uranium cycle by either a plutonium-topped thorium cycle or plutonium recycle, beginning between 2010 and 2025. It is also found that the uranium resource position is sound in terms of both known resources and production capability. Moreover, introduction of the low-enriched-uranium fuel cycle and 1250 MWe reactor units will assure the economic viability of nuclear power until at least 2020, even if uranium prices increase at a rate of 3.5% above inflation. The interrelationship between these two conclusions lies in the tremendous incentive for exploration which will occur if the real uranium price escalation rate is high. From a competitive viewpoint, nuclear power can withstand increases in the price of uranium. However, such increases will likely further expand the resource base, making nuclear an even more reliable energy source. (auth)

Life Cycle Management

DEFF Research Database (Denmark)

Bey, Niki

2018-01-01

This chapter gives an overview of Life Cycle Management (LCM)—a discipline that deals with the managerial tasks related to practicing sustainable development in an organisation . Just as Life Cycle Assessment, LCM advocates the life cycle perspective , and it applies this perspective in decision...

BWROPT: A multi-cycle BWR fuel cycle optimization code

Energy Technology Data Exchange (ETDEWEB)

Ottinger, Keith E.; Maldonado, G. Ivan, E-mail: Ivan.Maldonado@utk.edu

2015-09-15

Highlights: • A multi-cycle BWR fuel cycle optimization algorithm is presented. • New fuel inventory and core loading pattern determination. • The parallel simulated annealing algorithm was used for the optimization. • Variable sampling probabilities were compared to constant sampling probabilities. - Abstract: A new computer code for performing BWR in-core and out-of-core fuel cycle optimization for multiple cycles simultaneously has been developed. Parallel simulated annealing (PSA) is used to optimize the new fuel inventory and placement of new and reload fuel for each cycle considered. Several algorithm improvements were implemented and evaluated. The most significant of these are variable sampling probabilities and sampling new fuel types from an ordered array. A heuristic control rod pattern (CRP) search algorithm was also implemented, which is useful for single CRP determinations, however, this feature requires significant computational resources and is currently not practical for use in a full multi-cycle optimization. The PSA algorithm was demonstrated to be capable of significant objective function reduction and finding candidate loading patterns without constraint violations. The use of variable sampling probabilities was shown to reduce runtime while producing better results compared to using constant sampling probabilities. Sampling new fuel types from an ordered array was shown to have a mixed effect compared to random new fuel type sampling, whereby using both random and ordered sampling produced better results but required longer runtimes.

Sulfur cycle

Digital Repository Service at National Institute of Oceanography (India)

LokaBharathi, P.A.

Microbes, especially bacteria, play an important role in oxidative and reductive cycle of sulfur. The oxidative part of the cycle is mediated by photosynthetic bacteria in the presence of light energy and chemosynthetic forms in the absence of light...

Fast Reactor Fuel Cycle Cost Estimates for Advanced Fuel Cycle Studies

International Nuclear Information System (INIS)

Harrison, Thomas

2013-01-01

Presentation Outline: • Why Do I Need a Cost Basis?; • History of the Advanced Fuel Cycle Cost Basis; • Description of the Cost Basis; • Current Work; • Fast Reactor Fuel Cycle Applications; • Sample Fuel Cycle Cost Estimate Analysis; • Future Work

Essays on economic cycles

NARCIS (Netherlands)

Groot, de E.A. (Bert)

2006-01-01

Schumpeter’s line of thought of multiple economic cycles is further investigated. The existence of multiple cycles in economic variables is demonstrated. In basic innovations five different cycles are found. Multiple cycle structures are shown in various macro-economic variables from the United

Nuclear-fuel-cycle education: Module 1. Nuclear fuel cycle overview

International Nuclear Information System (INIS)

Eckhoff, N.D.

1981-07-01

This educational module is an overview of the nuclear-fule-cycle. The overview covers nuclear energy resources, the present and future US nuclear industry, the industry view of nuclear power, the International Nuclear Fuel Cycle Evaluation program, the Union of Concerned Scientists view of the nuclear-fuel-cycle, an analysis of this viewpoint, resource requirements for a model light water reactor, and world nuclear power considerations

Thorium cycles and proliferation

International Nuclear Information System (INIS)

Lovins, A.B.

1979-01-01

This paper analyzes several prevalent misconceptions about nuclear fuel cycles that breed fissile uranium-233 from thorium. Its main conclusions are: U-233, despite the gamma radioactivity of associated isotopes, is a rather attractive material for making fission bombs, and is a credible material for subnational as well as national groups to use for this purpose; (2) pure thorium cycles, which in effect merely substitute U-233 for Pu, would take many decades and much U to establish, and offer no significant safeguards advantage over Pu, cycles; (3) denatured Th-U cycles, which dilute the U-233 with inert U-238 to a level not directly usable in bombs, are not an effective safeguard even against subnational bomb-making; (4) several other features of mixed Th-U cycles are rather unattractive from a safeguards point of view; (5) thus, Th cycles of any kind are not a technical fix for proliferation (national or subnational) and, though probably more safeguardable than Pu cycles, are less so than once-through U cycles that entail no reprocessing; (6) while thorium cycles have some potential technical advantages, including flexibility, they cannot provide major savings in nuclear fuel resources compared to simpler ways of saving neutrons and U; and (7) while advocates of nuclear power may find Th cycles worth exploring, such cycles do not differ fundamentally from U cycles in any of the respects--including safeguards and fuel resources--that are relevant to the broader nuclear debate, and should not be euphorically embraced as if they did

Drivers of cycling demand and cycling futures in the Danish context

DEFF Research Database (Denmark)

Analysis of the time trend in cycling mode share based on longest possible time series. Logistic regression model of cycling as mode choice as basis for studying ‘driver variables’ contribution to time trend. Describing important vectors of change behind the time trend.......Analysis of the time trend in cycling mode share based on longest possible time series. Logistic regression model of cycling as mode choice as basis for studying ‘driver variables’ contribution to time trend. Describing important vectors of change behind the time trend....

Assessing Cycling Participation in Australia

Directory of Open Access Journals (Sweden)

Chris Rissel

2013-01-01

Full Text Available Planning and evaluating cycling programs at a national or state level requires accurate measures of cycling participation. However, recent reports of cycling participation have produced very different estimates. This paper examines the reported rates of cycling in five recent population surveys of cycling. Three surveys (one national and two from Sydney asking respondents when they last rode a bicycle generated cycling participation (cycled in the past year estimates of 29.7%, 34.1% and 28.9%. Two other national surveys which asked participants to recall (unprompted any physical activity done for exercise, recreation or sport in the previous 12 months, estimated cycling in the past year as 11.1% and 6.5%. While unprompted recall of cycling as a type of physical activity generates lower estimates of cycling participation than specific recall questions, both assessment approaches produced similar patterns of cycling by age and sex with both approaches indicating fewer women and older adults cycling. The different question styles most likely explain the substantial discrepancies between the estimates of cycling participation. Some differences are to be expected due to sampling variability, question differences, and regional variation in cycling.

Large-N behaviour of string solutions in the Heisenberg model

CERN Document Server

Fujita, T; Takahashi, H

2003-01-01

We investigate the large-N behaviour of the complex solutions for the two-magnon system in the S = 1/2 Heisenberg XXZ model. The Bethe ansatz equations are numerically solved for the string solutions with a new iteration method. Clear evidence of the violation of the string configurations is found at N = 22, 62, 121, 200, 299, 417, but the broken states are still Bethe states. The number of Bethe states is consistent with the exact diagonalization, except for one singular state.

Life-cycle cost analysis of adsorption cycles for desalination

KAUST Repository

Thu, Kyaw; Chakraborty, A.; Saha, B.B.; Chun, Won Gee; Ng, K.C.

2010-01-01

This paper presents the thermo-economic analysis of the adsorption desalination (AD) cycle that is driven by low-temperature waste heat from exhaust of industrial processes or renewable sources. The AD cycle uses an adsorbent such as the silica gel

On approximating restricted cycle covers

NARCIS (Netherlands)

Manthey, Bodo

2008-01-01

A cycle cover of a graph is a set of cycles such that every vertex is part of exactly one cycle. An $L$-cycle cover is a cycle cover in which the length of every cycle is in the set $L$. The weight of a cycle cover of an edge-weighted graph is the sum of the weights of its edges. We come close to

Nuclear power fuel cycle

International Nuclear Information System (INIS)

Havelka, S.; Jakesova, L.

1982-01-01

Economic problems are discussed of the fuel cycle (cost of the individual parts of the fuel cycle and the share of the fuel cycle in the price of 1 kWh), the technological problems of the fuel cycle (uranium ore mining and processing, uranium isotope enrichment, the manufacture of fuel elements, the building of long-term storage sites for spent fuel, spent fuel reprocessing, liquid and gaseous waste processing), and the ecologic aspects of the fuel cycle. (H.S.)

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Cycle-validation criteria for operation over specified duty cycles. 1065.514 Section 1065.514 Protection of Environment ENVIRONMENTAL... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...

Benefits of cycle stretchout in pressurized water reactor extended-burnup fuel cycles

International Nuclear Information System (INIS)

Matzie, R.A.; Leung, D.C.; Liu, Y.; Beekmann, R.W.

1981-01-01

Nuclear reactors are inherently capable of operating for a substantial period beyond their nominal end of cycle (EOC) as a result of negative moderator and fuel temperature coefficients and the decrease in xenon poisoning with lower core power levels. This inherent capability can be used to advantage to reduce annual uranium makeup requirements and cycle energy costs by the use of planned EOC stretchout. This paper discusses the fuel utilization efficiency and economics of both the five-batch, extended-burnup cycle and the three-batch, standard-burnup cycle, which can be improved by employing planned EOC (end of cycle) stretchout. 11 refs

Denatured fuel cycles

International Nuclear Information System (INIS)

Till, C.E.

1979-01-01

This paper traces the history of the denatured fuel concept and discusses the characteristics of fuel cycles based on the concept. The proliferation resistance of denatured fuel cycles, the reactor types they involve, and the limitations they place on energy generation potential are discussed. The paper concludes with some remarks on the outlook for such cycles

Edgeworth cycles revisited

International Nuclear Information System (INIS)

Doyle, Joseph; Muehlegger, Erich; Samphantharak, Krislert

2010-01-01

Some gasoline markets exhibit remarkable price cycles, where price spikes are followed by a series of small price declines: a pattern consistent with a model of Edgeworth cycles described by Maskin and Tirole. We extend the model and empirically test its predictions with a new dataset of daily station-level prices in 115 US cities. Consistent with the theory, and often in contrast with previous empirical work, we find the least and most concentrated markets are much less likely to exhibit cycling behavior both within and across cities; areas with more independent convenience-store gas stations are also more likely to cycle. (author)

Fuel cycle management

International Nuclear Information System (INIS)

Herbin, H.C.

1977-01-01

The fuel cycle management is more and more dependent on the management of the generation means among the power plants tied to the grid. This is due mainly because of the importance taken by the nuclear power plants within the power system. The main task of the fuel cycle management is to define the refuelling pattern of the new and irradiated fuel assemblies to load in the core as a function of: 1) the differences which exist between the actual conditions of the core and what was expected for the present cycle, 2) the operating constraints and the reactor availability, 3) the technical requirements in safety and the technological limits of the fuel, 4) the economics. Three levels of fuel cycle management can be considered: 1) a long term management: determination of enrichments and expected cycle lengths, 2) a mid term management whose aim corresponds to the evaluation of the batch to load within the core as a function of both: the next cycle length to achieve and the integrated power history of all the cycles up to the present one, 3) a short term management which deals with the updating of the loaded fuel utilisations to take into account the operation perturbations, or with the alteration of the loading pattern of the next batch to respect unexpected conditions. (orig.) [de

Exergoeconomic comparison of TLC (trilateral Rankine cycle), ORC (organic Rankine cycle) and Kalina cycle using a low grade heat source

International Nuclear Information System (INIS)

Yari, M.; Mehr, A.S.; Zare, V.; Mahmoudi, S.M.S.; Rosen, M.A.

2015-01-01

Recently, the TLC (trilateral power cycle) has attracted significant interest as it provides better matching between the temperature profiles in the evaporator compared to conventional power cycles. This article investigates the performance of this cycle and compares it with those for the ORC (organic Rankine cycle) and the Kalina cycle, from the viewpoints of thermodynamics and thermoeconomics. A low-grade heat source with a temperature of 120 °C is considered for all the three systems. Parametric studies are performed for the systems for several working fluids in the ORC and TLC. The systems are then optimized for either maximum net output power or minimum product cost, using the EES (engineering equation solver) software. The results for the TLC indicate that an increase in the expander inlet temperature leads to an increase in net output power and a decrease in product cost for this power plant, whereas this is not the case for the ORC system. It is found that, although the TLC can achieve a higher net output power compared with the ORC and Kalina (KCS11 (Kalina cycle system 11)) systems, its product cost is greatly affected by the expander isentropic efficiency. It is also revealed that using n-butane as the working fluid can result in the lowest product cost in the ORC and the TLC. In addition, it is observed that, for both the ORC and Kalina systems, the optimum operating condition for maximum net output power differs from that for minimum product cost. - Highlights: • Exergoeconomic analysis of trilateral Rankine cycle is performed. • The system performance is compared with Organic Rankine and Kalina cycles. • Net power from trilateral Rankine cycle is higher than the other power systems. • Superiority of trilateral cycle depends on its expander isentropic efficiency

Out-of-core fuel cycle optimization for nonequilibrium cycles

International Nuclear Information System (INIS)

Comes, S.A.; Turinsky, P.J.

1988-01-01

A methodology has been developed for determining the family of near-optimum fuel management schemes that minimize the levelized fuel cycle costs of a light water reactor over a multicycle planning horizon. Feed batch enrichments and sizes, burned batches to reinsert, and burnable poison loadings are determined for each cycle in the planning horizon. Flexibility in the methodology includes the capability to assess the economic benefits of various partially burned bath reload strategies as well as the effects of using split feed enrichments and enrichment palettes. Constraint limitations are imposed on feed enrichments, discharge burnups, moderator temperature coefficient, and cycle energy requirements

Air bottoming cycle, an alternative to combined cycles. Final report

Energy Technology Data Exchange (ETDEWEB)

Kaikko, J. [Royal Inst. of Techn., Stockholm (Sweden). Dept. of Energy Technology

2001-10-01

In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or

Reference: 279 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available ork, N.Y.) Bandyopadhyay Anindita|Blakeslee Joshua|Gaxiola Roberto|Gilroy Simon|Khodakovskaya Mariya|Krizek ...Beth|Li Jisheng|Murphy Angus S|Peer Wendy Ann|Richards Elizabeth L|Richter Gregory|Titapiwantakun Boosaree|Undurraga Soledad|Yang Haibing

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'Benefits cycle' replacing premium cycle as consumerism takes hold.

Science.gov (United States)

2002-05-01

The traditional premium cycle of ups and downs in rates is giving way to a new phenomenon--driven by the advent of consumerism in health care--termed the "benefits cycle" by one consultant. Rather than shifts in rates, he argues, the future will see shifts in benefits packages.

Natural cycle IVF with and without terminal HCG: learning from failed cycles.

Science.gov (United States)

Lenton, Elizabeth A

2007-08-01

Natural cycle IVF, without the use of LH down-regulation, is difficult because women start spontaneous LH surges at any time of the day and on any day of the week. This is not readily compatible with delivery of a routine IVF service and so historically the natural cycle has been modified by the use of human chorionic gonadotrophin (HCG) to make the natural cycle fit convenient clinical practice. This report re-evaluates data collected some years ago and seeks to determine whether the use of HCG is ultimately beneficial. Two large series of natural cycle IVF where only LH monitoring was performed (534 cycles) or where this was combined with HCG as necessary (241 cycles) were analysed. In essence, the use of HCG introduced as many problems as it overcame: there was no net benefit with respect to the number of eggs collected or clinical pregnancies generated. In fact there was an overall deterioration in all indices. The principle difficulties with natural cycle IVF are those associated with the prediction of follicle maturity and hence timing egg collection, and the conflict between costly and intrusively frequent monitoring with simpler but far less effective approaches.

Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger

Science.gov (United States)

Greene, William D. (Inventor)

2008-01-01

A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.

Ammonia-water Rankine cycle

International Nuclear Information System (INIS)

Bo Hanliang; Ma Changwen; Wu Shaorong

1997-01-01

On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

Study on the supercritical CO2 power cycles for landfill gas firing gas turbine bottoming cycle

International Nuclear Information System (INIS)

Kim, Min Seok; Ahn, Yoonhan; Kim, Beomjoo; Lee, Jeong Ik

2016-01-01

In this paper, a comparison of nine supercritical carbon dioxide (S-CO 2 ) bottoming power cycles in conjunction with a topping cycle of landfill gas (LFG) fired 5MWe gas turbine is presented. For the comparison purpose, a sensitivity study of the cycle design parameters for nine different cycles was conducted and each cycle thermodynamic performance is evaluated. In addition, the cycle performance evaluation dependency on the compressor inlet temperature variation is performed to investigate how S-CO 2 cycles sensitive to the heat sink temperature variation. Furthermore, the development of new S-CO 2 cycle layouts is reported and the suggested cycles' performances are compared to the existing cycle layouts. It was found that a recompression cycle is not suitable for the bottoming cycle application, but a partial heating cycle has relatively higher net produced work with a simple layout and small number of components. Although a dual heated and flow split cycle has the highest net produced work, it has disadvantages of having numerous components and complex process which requires more sophisticated operational strategies. This study identified that the recuperation process is much more important than the intercooling process to the S-CO 2 cycle design for increasing the thermal efficiency and the net produced work point of view. - Highlights: • Study of nine S-CO 2 power cycle layouts for a small scale landfill gas power generation application. • Development of new S-CO 2 cycle layouts. • Sensitivity analysis of S-CO 2 cycles to evaluate and compare nine cycles' performances.

A comparison of advanced heat recovery power cycles in a combined cycle for large ships

International Nuclear Information System (INIS)

Larsen, Ulrik; Sigthorsson, Oskar; Haglind, Fredrik

2014-01-01

Strong motivation exists within the marine sector to reduce fuel expenses and to comply with ever stricter emission regulations. Heat recovery can address both of these issues. The ORC (organic Rankine cycle), the Kalina cycle and the steam Rankine cycle have received the majority of the focus in the literature. In the present work we compare these cycles in a combined cycle application with a large marine two-stroke diesel engine. We present an evaluation of the efficiency and the environmental impact, safety concerns and practical aspects of each of the cycles. A previously validated numerical engine model is combined with a turbocharger model and bottoming cycle models written in Matlab. Genetic algorithm optimisation results suggest that the Kalina cycle possess no significant advantages compared to the ORC or the steam cycle. While contributing to very high efficiencies, the organic working fluids possess high global warming potentials and hazard levels. It is concluded that the ORC has the greatest potential for increasing the fuel efficiency, and the combined cycle offers very high thermal efficiency. While being less efficient, the steam cycle has the advantages of being well proven, harmless to the environment as well as being less hazardous in comparison. - Highlights: • We compare steam, ORC (organic Rankine cycle) and Kalina cycles for waste heat recovery in marine engines. • We evaluate the efficiency and important qualitative differences. • The Kalina cycle presents no apparent advantages. • The steam cycle is well known, harmless and has a high efficiency. • The ORC has the highest efficiency but also important drawbacks

Effect of cycle coupling-configuration on energy cascade utilization for a new power and cooling cogeneration cycle

International Nuclear Information System (INIS)

Jing, Xuye; Zheng, Danxing

2014-01-01

Highlights: • A new power and cooling cogeneration cycle was proposed. • The thermophysical properties and the performance of the new cycle were calculated. • Different cycle coupling-configurations were analyzed. • The energy efficiency boosting mechanism of the new cycle was elucidated. - Abstract: To recover mid-low grade heat, a new power/cooling cogeneration cycle was proposed by combining the Kalina cycle and the double-effect ammonia–water absorption refrigeration (DAAR) cycle together, and the equivalent heat-to-power and exergy efficiencies of the cogeneration cycle reached 41.18% and 58.00%, respectively. To determine the effect of cycle coupling-configuration on energy cascade utilization for the new cycle, the cycle coupling-configuration of the Kalina and DAAR cycles were first analyzed, after which the cycle coupling-configuration of the new cycle was analyzed. Analysis results showed that the cycle coupling-configuration of the new cycle enhanced the energy cascade utilization. Furthermore, the energy efficiency boosting mechanism of the new cycle was elucidated

Air bottoming cycle, an alternative to combined cycles. Final report

Energy Technology Data Exchange (ETDEWEB)

Kaikko, J. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

2002-02-01

In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or

Very high cycle fatigue testing of concrete using ultrasonic cycling

Energy Technology Data Exchange (ETDEWEB)

Karr, Ulrike; Schuller, Reinhard; Fitzka, Michael; Mayer, Herwig [Univ. of Natural Resources and Life Sciences, Vienna (Austria). Inst. of Physics and Materials Science; Denk, Andreas; Strauss, Alfred [Univ. of Natural Resources and Life Sciences, Vienna (Austria)

2017-06-01

The ultrasonic fatigue testing method has been further developed to perform cyclic compression tests with concrete. Cylindrical specimens vibrate in resonance at a frequency of approximately 20 kHz with superimposed compressive static loads. The high testing frequency allows time-saving investigations in the very high cycle fatigue regime. Fatigue tests were carried out on ''Concrete 1'' (compressive strength f{sub c} = 80 MPa) and ''Concrete 2'' (f{sub c} = 107 MPa) under purely compressive loading conditions. Experiments at maximum compressive stresses of 0.44 f{sub c} (Concrete 1) and 0.38 f{sub c} (Concrete 2) delivered specimen failures above 109 cycles, indicating that no fatigue limit exists for concrete below one billion load cycles. Resonance frequency, power required to resonate the specimen and second order harmonics of the vibration are used to monitor fatigue damage in situ. Specimens were scanned by X-ray computed tomography prior to and after testing. Fatigue cracks were produced by ultrasonic cycling in the very high cycle fatigue regime at interfaces of grains as well as in cement. The possibilities as well as limitations of ultrasonic fatigue testing of concrete are discussed.

International Business Cycle

OpenAIRE

Marek Lubiński

2007-01-01

Prime stylized facts of international business cycle theory refer to positive correlation in the cyclical components of important macroeconomic variables across countries. However a number of indicators of business cycle synchronization do not point to clear trends. It can be ascribed to the fact that different forces influence level of business cycle correlation. When investigating into the forces behind the commonness in aggregate fluctuations economic research seems to have pointed in two ...

Nuclear fuel cycle system analysis

International Nuclear Information System (INIS)

Ko, W. I.; Kwon, E. H.; Kim, S. G.; Park, B. H.; Song, K. C.; Song, D. Y.; Lee, H. H.; Chang, H. L.; Jeong, C. J.

2012-04-01

The nuclear fuel cycle system analysis method has been designed and established for an integrated nuclear fuel cycle system assessment by analyzing various methodologies. The economics, PR(Proliferation Resistance) and environmental impact evaluation of the fuel cycle system were performed using improved DB, and finally the best fuel cycle option which is applicable in Korea was derived. In addition, this research is helped to increase the national credibility and transparency for PR with developing and fulfilling PR enhancement program. The detailed contents of the work are as follows: 1)Establish and improve the DB for nuclear fuel cycle system analysis 2)Development of the analysis model for nuclear fuel cycle 3)Preliminary study for nuclear fuel cycle analysis 4)Development of overall evaluation model of nuclear fuel cycle system 5)Overall evaluation of nuclear fuel cycle system 6)Evaluate the PR for nuclear fuel cycle system and derive the enhancement method 7)Derive and fulfill of nuclear transparency enhancement method The optimum fuel cycle option which is economical and applicable to domestic situation was derived in this research. It would be a basis for establishment of the long-term strategy for nuclear fuel cycle. This work contributes for guaranteeing the technical, economical validity of the optimal fuel cycle option. Deriving and fulfillment of the method for enhancing nuclear transparency will also contribute to renewing the ROK-U.S Atomic Energy Agreement in 2014

KOH concentration effect on cycle life of nickel-hydrogen cells. III - Cycle life test

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1988-01-01

A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

Driving and engine cycles

CERN Document Server

Giakoumis, Evangelos G

2017-01-01

This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

The heat engine cycle, the heat removal cycle, and ergonomics of the control room displays

International Nuclear Information System (INIS)

Beltracchi, L.

1986-01-01

This paper discusses and illustrates the ergonomics of an integrated display, which will allow operators to monitor the heat engine cycle during normal operation of the plant, and the heat removal cycle during emergency operation of the plant. A computer-based iconic display is discussed as an overview to monitor these cycles. Specific emphasis is placed upon the process variables and process functions within each cycle, and the action of control systems and engineered safeguard systems within each cycle. This paper contains examples of display formats for the heat engine cycle and the heat removal cycle in a pressurized water reactor

Novel combined cycle configurations for propane pre-cooled mixed refrigerant (APCI) natural gas liquefaction cycle

International Nuclear Information System (INIS)

Mortazavi, Amir; Alabdulkarem, Abdullah; Hwang, Yunho; Radermacher, Reinhard

2014-01-01

Highlights: • 10 New LNG plants driver cycle enhancement configurations were developed. • All the 14 enhancement options design variables were optimized to demonstrate their energy saving potentials. • The best driver cycle enhancement option improved the driver cycle energy efficiency by 38%. • The effects of technological advancements on the performances of the enhancement options were studied. - Abstract: A significant amount of energy is required for natural gas liquefaction. Due to the production scale of LNG plants, they consume an intensive amount of energy. Consequently, any enhancement to the energy efficiency of LNG plants will result in a considerable reduction in natural gas consumption and CO 2 emission. Compressor drivers are the main energy consumer in the LNG plants. In this paper, 14 different driver cycle enhancement options were considered. A number of these options have not been proposed for the LNG plants. The new driver cycle development was performed by analyzing and optimizing the design variables of four conventional driver cycle enhancement options. The optimization results were used to develop more efficient cycles through mitigating the active constrains and driver cycle innovations. Based on the current available technologies five of our newly developed driver cycle configurations have higher efficiency than the most efficient existing conventional driver cycle. The best developed driver cycle enhancement option improved the base driver cycle energy efficiency by 38%. The effects of technological advancement on the performances of the all driver cycle enhancement options were also considered

Chords in longest cycles

DEFF Research Database (Denmark)

Thomassen, Carsten

2017-01-01

If a graph G is 3-connected and has minimum degree at least 4, then some longest cycle in G has a chord. If G is 2-connected and cubic, then every longest cycle in G has a chord.......If a graph G is 3-connected and has minimum degree at least 4, then some longest cycle in G has a chord. If G is 2-connected and cubic, then every longest cycle in G has a chord....

Temporal fluxomics reveals oscillations in TCA cycle flux throughout the mammalian cell cycle.

Science.gov (United States)

Ahn, Eunyong; Kumar, Praveen; Mukha, Dzmitry; Tzur, Amit; Shlomi, Tomer

2017-11-06

Cellular metabolic demands change throughout the cell cycle. Nevertheless, a characterization of how metabolic fluxes adapt to the changing demands throughout the cell cycle is lacking. Here, we developed a temporal-fluxomics approach to derive a comprehensive and quantitative view of alterations in metabolic fluxes throughout the mammalian cell cycle. This is achieved by combining pulse-chase LC-MS-based isotope tracing in synchronized cell populations with computational deconvolution and metabolic flux modeling. We find that TCA cycle fluxes are rewired as cells progress through the cell cycle with complementary oscillations of glucose versus glutamine-derived fluxes: Oxidation of glucose-derived flux peaks in late G1 phase, while oxidative and reductive glutamine metabolism dominates S phase. These complementary flux oscillations maintain a constant production rate of reducing equivalents and oxidative phosphorylation flux throughout the cell cycle. The shift from glucose to glutamine oxidation in S phase plays an important role in cell cycle progression and cell proliferation. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Alternative fuel cycles

International Nuclear Information System (INIS)

Penn, W.J.

1979-05-01

Uranium resource utilization and economic considerations provide incentives to study alternative fuel cycles as future options to the PHWR natural uranium cycle. Preliminary studies to define the most favourable alternatives and their possible introduction dates are discussed. The important and uncertain components which influence option selection are reviewed, including nuclear capacity growth, uranium availability and demand, economic potential, and required technological developments. Finally, a summary of Ontario Hydro's program to further assess cycle selection and define development needs is given. (auth)

Educational Business Cycles

DEFF Research Database (Denmark)

Tepe, Markus; Vanhuysse, Pieter

Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...... teacher employment patterns at the state level in Germany and find strong evidence of cycling mechanisms, in the form of electioneering and honeymooning. Against a backdrop of a continuously shrinking total teachers' pool, German state-level incumbents accelerate the hiring of new teachers during election...... periods and partly reverse this during politically safer points in the electoral cycle. Cycles are mediated by issue salience: heightened attention to German public schooling after the notorious PISA-2000 tests further strengthens the manipulation of new teacher hiring for electoral purposes....

Educational Business Cycles

DEFF Research Database (Denmark)

Tepe, Markus; Vanhuysse, Pieter

2009-01-01

Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...... teacher employment patterns at the state level in Germany and find strong evidence of cycling mechanisms, in the form of electioneering and honeymooning. Against a backdrop of a continuously shrinking total teachers' pool, German state-level incumbents accelerate the hiring of new teachers during election...... periods and partly reverse this during politically safer points in the electoral cycle. Cycles are mediated by issue salience: heightened attention to German public schooling after the notorious PISA-2000 tests further strengthens the manipulation of new teacher hiring for electoral purposes....

Termination of cycle rewriting

NARCIS (Netherlands)

Zantema, H.; König, B.; Bruggink, H.J.S.; Dowek, G.

2014-01-01

String rewriting can not only be applied on strings, but also on cycles and even on general graphs. In this paper we investigate termination of string rewriting applied on cycles, shortly denoted as cycle rewriting, which is a strictly stronger requirement than termination on strings. Most

The Nuclear Fuel Cycle

International Nuclear Information System (INIS)

2011-08-01

This brochure describes the nuclear fuel cycle, which is an industrial process involving various activities to produce electricity from uranium in nuclear power reactors. The cycle starts with the mining of uranium and ends with the disposal of nuclear waste. The raw material for today's nuclear fuel is uranium. It must be processed through a series of steps to produce an efficient fuel for generating electricity. Used fuel also needs to be taken care of for reuse and disposal. The nuclear fuel cycle includes the 'front end', i.e. preparation of the fuel, the 'service period' in which fuel is used during reactor operation to generate electricity, and the 'back end', i.e. the safe management of spent nuclear fuel including reprocessing and reuse and disposal. If spent fuel is not reprocessed, the fuel cycle is referred to as an 'open' or 'once-through' fuel cycle; if spent fuel is reprocessed, and partly reused, it is referred to as a 'closed' nuclear fuel cycle.

Can cycling safety be improved by opening all unidirectional cycle paths for cycle traffic in both directions? A theoretical examination of available literature and data.

Science.gov (United States)

Methorst, Rob; Schepers, Paul; Kamminga, Jaap; Zeegers, Theo; Fishman, Elliot

2017-08-01

Many studies have found bicycle-motor vehicle crashes to be more likely on bidirectional cycle paths than on unidirectional cycle paths because drivers do not expect cyclists riding at the right side of the road. In this paper we discuss the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions prevent this lack of expectancy and accordingly improves cycling safety. A new national standard requires careful consideration because a reversal is difficult once cyclists are used to their new freedom of route choice. We therefore explored the hypothesis using available data, research, and theories. The results show that of the length of cycle paths along distributor roads in the Netherlands, 72% is bidirectional. If drivers would become used to cyclists riding at the left side of the road, this result raises the question of why bidirectional cycle paths in the Netherlands still have a poor safety record compared to unidirectional cycle paths. Moreover, our exploration suggested that bidirectional cycle paths have additional safety problems. It increases the complexity of unsignalized intersections because drivers have to scan more directions in a short period of time. Moreover, there are some indications that the likelihood of frontal crashes between cyclists increases. We reject the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions will improve cycle safety. We recommend more attention for mitigating measures given the widespread application of bidirectional cycle paths in the Netherlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nuclear Fuel Cycle Information System. A directory of nuclear fuel cycle facilities. 2009 ed

International Nuclear Information System (INIS)

2009-04-01

The Nuclear Fuel Cycle Information System (NFCIS) is an international directory of civilian nuclear fuel cycle facilities, published online as part of the Integrated Nuclear Fuel Cycle Information System (iNFCIS: http://www-nfcis.iaea.org/). This is the fourth hardcopy publication in almost 30 years and it represents a snapshot of the NFCIS database as of the end of 2008. Together with the attached CD-ROM, it provides information on 650 civilian nuclear fuel cycle facilities in 53 countries, thus helping to improve the transparency of global nuclear fuel cycle activities

Entrepreneurship and the business cycle

NARCIS (Netherlands)

Koellinger, Philipp D.; Thurik, A. Roy

2012-01-01

We find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972 to 2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment cycle. We

Continuation of connecting orbits in 3d-ODEs. (ii) cycle-to-cycle connections.

NARCIS (Netherlands)

Doedel, E.J.; Kooi, B.W.; van Voorn, G.A.K.; Kuznetzov, Y.A.

2009-01-01

In Part I of this paper we have discussed new methods for the numerical continuation of point-to-cycle connecting orbits in three-dimensional autonomous ODE's using projection boundary conditions. In this second part we extend the method to the numerical continuation of cycle-to-cycle connecting

Jet cross sections in γ*γ-scattering at e+e- colliders in NLO QCD

International Nuclear Information System (INIS)

Poetter, B.

1999-01-01

Recent results from NLO QCD calculations for inclusive jet cross sections in γ*γ-scattering at e + e - colliders, especially for LEP, are reported. The virtuality Q 2 of the virtual photon is non-zero and can be unlimited large. The virtuality of the second photon is zero and the spectrum is calculated with the Weizsaecker-Williams approximation. Four components of the cross sections have to be distinguished, involving direct and resolved real and virtual photon contributions. Since Q 2 is non-zero, the virtual photon structure function is needed to calculate the contributions involving a resolved virtual photon

Resonant Coulomb excitation of atomic nuclei propagating through a crystal in the channeling mode

International Nuclear Information System (INIS)

Stepanov, A.V.

1996-01-01

The Coulomb-excitation total cross section and the distribution of decay products originating from a resonant state of a nucleus interacting with a crystal lattice has been calculated for the case of a single inelastic collision (with respect to internal degrees of freedom in a nucleus). These observables have been expressed in terms of time-dependent correlators which describe thermal oscillations of lattice nuclei and the motion of the center of mass of a nucleus propagating across a crystal target in the channelling mode. An expression generalizing the spectrum of equivalent photons calculated by the Weizsaecker-Williams method is given

Bethe, Hans Albrecht (1906-)

Science.gov (United States)

Murdin, P.

2000-11-01

Physicist, born in Strasburg, Germany (present-day France), Nobel prizewinner (1967). As professor of physics at Cornell University he worked out the nuclear reactions occurring in the Sun. He worked on the development of the atomic bomb in the Manhatten project, and, after the second World War, pursued again research on stellar nuclear energy sources and the origin of the chemical elements in th...

LIFE CYCLE OF INFORMATION SYSTEMS

Directory of Open Access Journals (Sweden)

Y. S. Sennik

2015-01-01

Full Text Available This work is a generalization of the theoretical propositions related to the life cycle of information systems. There was given the definition of the life cycle, specify which items you should include every step of the cycle. Describes the methodology division of the life cycle on the main stage, including methodology Rational Unified Process. The description of the fundamental standards in this area. Special attention was paid to the work of the basic life cycle models. It was carried out their comparative characteristics. On the basis of the theoretical propositions, it was concluded that the preferred model of the life cycle for the corporate network is a spiral model and the use of international standards in the life cycle saves a lot of effort, time and material resources.

Two Quantum Polytropic Cycles

Science.gov (United States)

Arias-Hernández, L. A.; Morales-Serrano, A. F.

2002-11-01

In this work we follow the Bender et al paper [1] to study the quantum analogues of the Stirling and Ericsson polytropic cycles. In the context of the classical thermodynamics, the Stirling and Ericsson cycles correspond to reversible heat engines with two isothermal processes joined by two polytropic branches which occur in a device called regenerator. If this device is an ideal one, the efficiency of these cycles is the Carnot efficiency. Here, we introduce the quantum analogues of the Stirling and Ericsson cycles, the first one based on a double square potential well with a finite potential barrier, since in this system the tunnel effect could be the analogue to the regeneration classical process, therefore the isochoric quantum branches would really correspond to an internal energy storage, and the last one with an unknown system where the isobaric quantum processes don't induce changes in its quantum state. With these systems the quantum engines have cycles consisting of polytropic and isothermal quantum processes analogues to the corresponding classical processes. We show that in both cases the quantum cycles have an efficiency given by ηCQM = 1 - EC/EH, which is the same expression for the quantum analogue of the Carnot cycle studied by Bender.

Increasing thermal efficiency of Rankine cycles by using refrigeration cycles: A theoretical analysis

International Nuclear Information System (INIS)

Sarr, Joachim-André Raymond; Mathieu-Potvin, François

2016-01-01

Highlights: • A new stratagem is proposed to improve thermal efficiency of Rankine cycles. • Three new configurations are optimized by means of numerical simulations. • The Rankine-1SCR design is advantageous for 1338 different fluid combinations. • The Rankine-2SCR design is advantageous for 772 different fluid combinations. • The Rankine-3SCR design is advantageous for 768 different fluid combinations. - Abstract: In this paper, three different modifications of the basic Rankine thermodynamic cycle are proposed. The objective is to increase the thermal efficiency of power systems based on Rankine cycles. The three new systems are named “Rankine-1SCR”, “Rankine-2SCR”, and “Rankine-3SCR” cycles, and they consist of linking a refrigeration cycle to the basic Rankine cycle. The idea is to use the refrigeration cycle to create a low temperature heat sink for the Rankine cycle. These three new power plant configurations are modeled and optimized with numerical tools, and then they are compared with the basic Rankine cycle. The objective function is the thermal efficiency of the systems (i.e., net power output (kW) divided by heat rate (kW) entering the system), and the design variables are the operating temperatures within the systems. Among the 84 × 84 (i.e., 7056) possible combinations of working and cooling fluids investigated in this paper, it is shown that: (i) the Rankine-1SCR system is advantageous for 1338 different fluid combinations, (ii) the Rankine-2SCR system is advantageous for 772 different fluid combinations, and (iii) the Rankine-3SCR system is advantageous for 768 different fluid combinations.

Hybrid Combined Cycles with Biomass and Waste Fired Bottoming Cycle - a Literature Study

Energy Technology Data Exchange (ETDEWEB)

Petrov, Miroslav P.

2002-02-01

Biomass is one of the main natural resources in Sweden. The present low-CO{sub 2} emission characteristics of the Swedish electricity production system (hydro and nuclear) can be retained only by expansion of biofuel applications for energy purposes. Domestic Swedish biomass resources are vast and renewable, but not infinite. They must be utilized as efficiently as possible, in order to make sure that they meet the conditions for sustainability in the future. Application of efficient power generation cycles at low costs is essential for meeting this challenge. This applies also to municipal solid waste incineration with energy extraction, which should be preferred to its dumping in landfills. Hybrid dual-fuel combined cycle units are a simple and affordable way to increase the electric efficiency of biofuel energy utilization, without big investments, uncertainties or loss of reliability arising from complicated technologies. Configurations of such power cycles are very flexible and reliable. Their potential for high electric efficiency in condensing mode, high total efficiency in combined heat and power mode and unrivalled load flexibility is explored in this project. The present report is a literature study that concentrates on certain biomass utilization technologies, in particular the design and performance of hybrid combined cycle power units of various configurations, with gas turbines and internal combustion engines as topping cycles. An overview of published literature and general development trends on the relevant topic is presented. The study is extended to encompass a short overview of biomass utilization as an energy source (focusing on Sweden), history of combined cycles development with reference especially to combined cycles with supplementary firing and coal-fired hybrid combined cycles, repowering of old steam units into hybrid ones and combined cycles for internal combustion engines. The hybrid combined cycle concept for municipal solid waste

Quantum group symmetries and completeness for \\boldsymbol {A}_{\\boldsymbol {2n}}^{\\boldsymbol{(2)}} open spin chains

Science.gov (United States)

Ahmed, Ibrahim; Nepomechie, Rafael I.; Wang, Chunguang

2017-07-01

We argue that the Hamiltonians for A(2)2n open quantum spin chains corresponding to two choices of integrable boundary conditions have the symmetries Uq(Bn) and Uq(Cn) , respectively. We find a formula for the Dynkin labels of the Bethe states (which determine the degeneracies of the corresponding eigenvalues) in terms of the numbers of Bethe roots of each type. With the help of this formula, we verify numerically (for a generic value of the anisotropy parameter) that the degeneracies and multiplicities of the spectra implied by the quantum group symmetries are completely described by the Bethe ansatz.

The exact solution and the finite-size behaviour of the Osp(1vertical stroke 2)-invariant spin chain

International Nuclear Information System (INIS)

Martins, M.J.

1995-01-01

We have solved exactly the Osp(1vertical stroke 2) spin chain by the Bethe ansatz approach. Our solution is based on an equivalence between the Osp(1vertical stroke 2) chain and a certain special limit of the Izergin-Korepin vertex model. The completeness of the Bethe ansatz equations is discussed for a system with four sites and the appearance of special string structures is noted. The Bethe ansatz presents an important phase factor which distinguishes the even and odd sectors of the theory. The finite-size properties are governed by a conformal field theory with central charge c=1. (orig.)

Central venous catheterization training: current perspectives on the role of simulation

Directory of Open Access Journals (Sweden)

Soffler MI

2018-05-01

Full Text Available Morgan I Soffler,1,2 Margaret M Hayes,2–4 C Christopher Smith3–5 1Harvard Combined Pulmonary and Critical Care Fellowship at Massachusetts General Hospital and Beth Israel Deaconess Medical Center, Boston, MA, USA; 2Division of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA; 3Internal Medicine Residency Program, Beth Israel Deaconess Medical Center, Boston, MA, USA; 4Shapiro Institute for Education and Research, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA; 5Division of General Internal Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA Abstract: Simulation is a popular and effective training modality in medical education across a variety of domains. Central venous catheterization (CVC is commonly undertaken by trainees, and carries significant risk for patient harm when carried out incorrectly. Multiple studies have evaluated the efficacy of simulation-based training programs, in comparison with traditional training modalities, on learner and patient outcomes. In this review, we discuss relevant adult learning principles that support simulation-based CVC training, review the literature on simulation-based CVC training, and highlight the use of simulation-based CVC training programs at various institutions. Keywords: simulation, central venous catheterization, assessment, competency, central line insertion

High-intensity cycle interval training improves cycling and running performance in triathletes.

Science.gov (United States)

Etxebarria, Naroa; Anson, Judith M; Pyne, David B; Ferguson, Richard A

2014-01-01

Effective cycle training for triathlon is a challenge for coaches. We compared the effects of two variants of cycle high-intensity interval training (HIT) on triathlon-specific cycling and running. Fourteen moderately-trained male triathletes ([Formula: see text]O2peak 58.7 ± 8.1 mL kg(-1) min(-1); mean ± SD) completed on separate occasions a maximal incremental test ([Formula: see text]O2peak and maximal aerobic power), 16 × 20 s cycle sprints and a 1-h triathlon-specific cycle followed immediately by a 5 km run time trial. Participants were then pair-matched and assigned randomly to either a long high-intensity interval training (LONG) (6-8 × 5 min efforts) or short high-intensity interval training (SHORT) (9-11 × 10, 20 and 40 s efforts) HIT cycle training intervention. Six training sessions were completed over 3 weeks before participants repeated the baseline testing. Both groups had an ∼7% increase in [Formula: see text]O2peak (SHORT 7.3%, ±4.6%; mean, ±90% confidence limits; LONG 7.5%, ±1.7%). There was a moderate improvement in mean power for both the SHORT (10.3%, ±4.4%) and LONG (10.7%, ±6.8%) groups during the last eight 20-s sprints. There was a small to moderate decrease in heart rate, blood lactate and perceived exertion in both groups during the 1-h triathlon-specific cycling but only the LONG group had a substantial decrease in the subsequent 5-km run time (64, ±59 s). Moderately-trained triathletes should use both short and long high-intensity intervals to improve cycling physiology and performance. Longer 5-min intervals on the bike are more likely to benefit 5 km running performance.

Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

DEFF Research Database (Denmark)

Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

2016-01-01

Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...

Menstrual cycle pattern and fertility

DEFF Research Database (Denmark)

Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

1999-01-01

To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss.......To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss....

Spatio-temporal structure and cycle to cycle variations of an in-cylinder tumbling flow

Science.gov (United States)

Voisine, M.; Thomas, L.; Borée, J.; Rey, P.

2011-05-01

The aim of this paper is to make use of PIV and high-speed PIV in a research engine of moderate tumbling ratio in order to analyze both the spatial structure of the flow and its temporal evolution during series of consecutive cycles. Appropriate analyzing tools are introduced, and four different points are addressed: (1) the chain of events driving the generation of the three-dimensional mean tumbling motion is investigated; (2) a Lagrangian analysis of the roll-up of the tumbling jet in individual cycles demonstrates a strong cycle to cycle variation during the compression phase (the rms of the position of the jet front being approximately 10% of the piston stroke); (3) focussing on the "breakdown" phase, phase invariant proper orthogonal decomposition enables us to distinguish cycles according to their structure near top dead center (TDC). We show that when the coherent energy of the flow is conserved, there is no increase in the fluctuating kinetic energy; (4) finally, the phase-averaged Reynolds stresses is decomposed into a contribution of the in-cycle coherence and the turbulence carried by the flow states. Approximately 30% of the fluctuating kinetic energy is due to cycle to cycle fluctuations in this chamber near TDC.

Nutrient cycling strategies.

NARCIS (Netherlands)

Breemen, van N.

1995-01-01

This paper briefly reviews pathways by which plants can influence the nutrient cycle, and thereby the nutrient supply of themselves and of their competitors. Higher or lower internal nutrient use efficiency positively feeds back into the nutrient cycle, and helps to increase or decrease soil

Universal cycle periods

NARCIS (Netherlands)

Groot, de E.A. (Bert); Franses, P.H.P.H.

2009-01-01

We present a meta-analysis of cycles in historical economic data. The literature on stochastic and deterministic cycles in variables such as the consumer price index, employment, interest rates, commodity prices, and GDP is huge and scattered, but our meta-analysis reveals various communalities. Our

Predicting the start and maximum amplitude of solar cycle 24 using similar phases and a cycle grouping

International Nuclear Information System (INIS)

Wang Jialong; Zong Weiguo; Le Guiming; Zhao Haijuan; Tang Yunqiu; Zhang Yang

2009-01-01

We find that the solar cycles 9, 11, and 20 are similar to cycle 23 in their respective descending phases. Using this similarity and the observed data of smoothed monthly mean sunspot numbers (SMSNs) available for the descending phase of cycle 23, we make a date calibration for the average time sequence made of the three descending phases of the three cycles, and predict the start of March or April 2008 for cycle 24. For the three cycles, we also find a linear correlation of the length of the descending phase of a cycle with the difference between the maximum epoch of this cycle and that of its next cycle. Using this relationship along with the known relationship between the rise-time and the maximum amplitude of a slowly rising solar cycle, we predict the maximum SMSN of cycle 24 of 100.2 ± 7.5 to appear during the period from May to October 2012. (letters)

Associations between urban form and cycling

DEFF Research Database (Denmark)

Nielsen, Thomas Alexander Sick; Olafsson, Anton Stahl; Carstensen, Trine Agervig

of National Travel Survey data indicated that established walkability factors such as density, connectivity and diversity are related to cycling, and that access to retail concentrations/centres, public transportation level-of-service, as well as competition between walking and cycling depending...... of cycling and the distance cycled. A high probability of cycling generally implies short cycling distances, which leads to non-uniform, non-monotonous relations between environmental indicators such as walkability and total cycling. Further analysis of primary data allowing a consideration of attitudes...

Characterizing cycle-to-cycle variations of the shedding cycle in the turbulent wake of a normal flat plate using generalized phase averages

Science.gov (United States)

Martinuzzi, Robert

2016-11-01

Quasi-periodic vortex shedding in the turbulent wake of a thin-flat plate placed normal to a uniform stream at Reynolds number of 6700 is investigated based on Particle Image Velocimetry experiments. The wake structure and vortex formation are characterized using a generalized phase average (GPA), a refinement of the triple decomposition of Reynolds and Hussain (1970) incorporating elements of mean-field theory (Stuart, 1958). The resulting analysis highlights the importance of cycle-to-cycle variations in characterizing vortex formation, wake topology and the residual turbulent Reynolds Stresses. For example, it is shown that during high-amplitude cycles vorticity is strongly concentrated within the well-organized shed vortices, whereas during low-amplitude cycles the shed vortices are highly distorted resulting in significant modulation of the shedding frequency. It is found that high-amplitude cycles contribute more to the coherent Reynolds stress field while the low-amplitude cycles contribute to the residual stress field. It is further shown that traditional phase-averaging techniques lead to an over-estimation of the residual stress field. Natural Sciences and Engineering Research Council of Canada.

Stability through cycles

NARCIS (Netherlands)

E.A. de Groot (Bert); Ph.H.B.F. Franses (Philip Hans)

2006-01-01

textabstractEconomic variables like GDP growth, employment, interest rates and consumption show signs of cyclical behavior. Many variables display multiple cycles, with lengths ranging in between 5 to even up to 100 years. We argue that multiple cycles can be associated with long-run stability of

Economics analysis of fuel cycle cost of fusion–fission hybrid reactors based on different fuel cycle strategies

Energy Technology Data Exchange (ETDEWEB)

Zu, Tiejun, E-mail: tiejun@mail.xjtu.edu.cn; Wu, Hongchun; Zheng, Youqi; Cao, Liangzhi

2015-01-15

Highlights: • Economics analysis of fuel cycle cost of FFHRs is carried out. • The mass flows of different fuel cycle strategies are established based on the equilibrium fuel cycle model. • The levelized fuel cycle costs of different fuel cycle strategies are calculated, and compared with current once-through fuel cycle. - Abstract: The economics analysis of fuel cycle cost of fusion–fission hybrid reactors has been performed to compare four fuel cycle strategies: light water cooled blanket burning natural uranium (Strategy A) or spent nuclear fuel (Strategy B), sodium cooled blanket burning transuranics (Strategy C) or minor actinides (Strategy D). The levelized fuel cycle costs (LFCC) which does not include the capital cost, operation and maintenance cost have been calculated based on the equilibrium mass flows. The current once-through (OT) cycle strategy has also been analyzed to serve as the reference fuel cycle for comparisons. It is found that Strategy A and Strategy B have lower LFCCs than OT cycle; although the LFCC of Strategy C is higher than that of OT cycle when the uranium price is at its nominal value, it would become comparable to that of OT cycle when the uranium price reaches its historical peak value level; Strategy D shows the highest LFCC, because it needs to reprocess huge mass of spent nuclear fuel; LFCC is sensitive to the discharge burnup of the nuclear fuel.

HTGR fuel and fuel cycle technology

International Nuclear Information System (INIS)

Lotts, A.L.; Coobs, J.H.

1976-08-01

The status of fuel and fuel cycle technology for high-temperature gas-cooled reactors (HTGRs) is reviewed. The all-ceramic core of the HTGRs permits high temperatures compared with other reactors. Core outlet temperatures of 740 0 C are now available for the steam cycle. For advanced HTGRs such as are required for direct-cycle power generation and for high-temperature process heat, coolant temperatures as high as 1000 0 C may be expected. The paper discusses the variations of HTGR fuel designs that meet the performance requirements and the requirements of the isotopes to be used in the fuel cycle. Also discussed are the fuel cycle possibilities, which include the low-enrichment cycle, the Th- 233 U cycle, and plutonium utilization in either cycle. The status of fuel and fuel cycle development is summarized

Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

Science.gov (United States)

Brewer, B J; Chlebowicz-Sledziewska, E; Fangman, W L

1984-11-01

During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic strains shows that cell cycle phase lengths are independent of cell ploidy and mating type.

On acyclicity of games with cycles

DEFF Research Database (Denmark)

Andersson, Klas Olof Daniel; Hansen, Thomas Dueholm; Gurvich, Vladimir

2010-01-01

We study restricted improvement cycles (ri-cycles) in finite positional n-person games with perfect information modeled by directed graphs (di-graphs) that may contain directed cycles (di-cycles). We assume that all these di-cycles form one outcome c, for example, a draw. We obtain criteria...

An integrated life cycle inventory for demolition processes in the context of life cycle sustainability assessment

DEFF Research Database (Denmark)

Bozhilova-Kisheva, Kossara Petrova; Hu, Mingming; van Roekel, Eric

2012-01-01

According to the Life Cycle Assessment in Building and Construction: State-of-the-Art Report (2003), the dismantling and demolition stage of the building life cycle is only sometimes included in the Life Cycle Inventory (LCI) when doing Life Cycle Assessments (LCA). The reason that it is less...... inventoried in a traditional LCA maybe because this stage is expected to have a negligible environmental impact comparing to other stages in the life cycle of the buildings. When doing a life cycle sustainability assessment considering not only environmental but also economic and social impacts, the impacts...

A comparison of advanced heat recovery power cycles in a combined cycle for large ships

DEFF Research Database (Denmark)

Larsen, Ulrik; Sigthorsson, Oskar; Haglind, Fredrik

2014-01-01

Strong motivation exists within the marine sector to reduce fuel expenses and to comply with ever stricter emission regulations. Heat recovery can address both of these issues. The ORC (organic Rankine cycle), the Kalina cycle and the steam Rankine cycle have received the majority of the focus...... fluids possess high global warming potentials and hazard levels. It is concluded that the ORC has the greatest potential for increasing the fuel efficiency, and the combined cycle offers very high thermal efficiency. While being less efficient, the steam cycle has the advantages of being well proven...

CANDU fuel-cycle vision

International Nuclear Information System (INIS)

Boczar, P.G.

1999-01-01

The fuel-cycle path chosen by a particular country will depend on a range of local and global factors. The CANDU reactor provides the fuel-cycle flexibility to enable any country to optimize its fuel-cycle strategy to suit its own needs. AECL has developed the CANFLEX fuel bundle as the near-term carrier of advanced fuel cycles. A demonstration irradiation of 24 CANFLEX bundles in the Point Lepreau power station, and a full-scale critical heat flux (CHF) test in water are planned in 1998, before commercial implementation of CANFLEX fuelling. CANFLEX fuel provides a reduction in peak linear element ratings, and a significant enhancement in thermalhydraulic performance. Whereas natural uranium fuel provides many advantages, the use of slightly enriched uranium (SEU) in CANDU reactors offers even lower fuel-cycle costs and other benefits, such as uprating capability through flattening the channel power distribution across the core. Recycled uranium (RU) from reprocessing spent PWR fuel is a subset of SEU that has significant economic promise. AECL views the use of SEU/RU in the CANFLEX bundle as the first logical step from natural uranium. High neutron economy enables the use of low-fissile fuel in CANDU reactors, which opens up a spectrum of unique fuel-cycle opportunities that exploit the synergism between CANDU reactors and LWRs. At one end of this spectrum is the use of materials from conventional reprocessing: CANDU reactors can utilize the RU directly without re-enrichment, the plutonium as conventional Mixed-oxide (MOX) fuel, and the actinide waste mixed with plutonium in an inert-matrix carrier. At the other end of the spectrum is the DUPIC cycle, employing only thermal-mechanical processes to convert spent LWR fuel into CANDU fuel, with no purposeful separation of isotopes from the fuel, and possessing a high degree of proliferation resistance. Between these two extremes are other advanced recycling options that offer particular advantages in exploiting the

CANDU fuel-cycle vision

International Nuclear Information System (INIS)

Boczar, P.G

1998-05-01

The fuel-cycle path chosen by a particular country will depend on a range of local and global factors. The CANDU reactor provides the fuel-cycle flexibility to enable any country to optimize its fuel-cycle strategy to suit its own needs. AECL has developed the CANFLEX fuel bundle as the near-term carrier of advanced fuel cycles. A demonstration irradiation of 24 CANFLEX bundles in the Point Lepreau power station, and a full-scale critical heat flux (CHF) test in water are planned in 1998, before commercial implementation of CANFLEX fuelling. CANFLEX fuel provides a reduction in peak linear element ratings, and a significant enhancement in thermalhydraulic performance. Whereas natural uranium fuel provides many advantages, the use of slightly enriched uranium (SEU) in CANDU reactors offers even lower fuel-cycle costs and other benefits, such as uprating capability through flattening the channel power distribution across the core. Recycled uranium (RU) from reprocessing spent PWR fuel is a subset of SEU that has significant economic promise. AECL views the use of SEU/RU in the CANFLEX bundle as the first logical step from natural uranium. High neutron economy enables the use of low-fissile fuel in CANDU reactors, which opens up a spectrum of unique fuel-cycle opportunities that exploit the synergism between CANDU reactors and LWRs. At one end of this spectrum is the use of materials from conventional reprocessing: CANDU reactors can utilize the RU directly without reenrichment, the plutonium as conventional mixed-oxide (MOX) fuel, and the actinide waste mixed with plutonium in an inert-matrix carrier. At the other end of the spectrum is the DUPIC cycle, employing only thermal-mechanical processes to convert spent LWR fuel into CANDU fuel, with no purposeful separation of isotopes from the fuel, and possessing a high degree of proliferation resistance. Between these two extremes are other advanced recycling options that offer particular advantages in exploiting the

Verifiable Fuel Cycle Simulation Model (VISION): A Tool for Analyzing Nuclear Fuel Cycle Futures

International Nuclear Information System (INIS)

Jacobson, Jacob J.; Piet, Steven J.; Matthern, Gretchen E.; Shropshire, David E.; Jeffers, Robert F.; Yacout, A.M.; Schweitzer, Tyler

2010-01-01

The nuclear fuel cycle consists of a set of complex components that are intended to work together. To support the nuclear renaissance, it is necessary to understand the impacts of changes and timing of events in any part of the fuel cycle system such as how the system would respond to each technological change, a series of which moves the fuel cycle from where it is to a postulated future state. The system analysis working group of the United States research program on advanced fuel cycles (formerly called the Advanced Fuel Cycle Initiative) is developing a dynamic simulation model, VISION, to capture the relationships, timing, and changes in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model components and some examples of how to use VISION. For example, VISION users can now change yearly the selection of separation or reactor technologies, the performance characteristics of those technologies, and/or the routing of material among separation and reactor types - with the model still operating on a PC in <5 min.

Part 5. Fuel cycle options

International Nuclear Information System (INIS)

Lineberry, M.J.; McFarlane, H.F.; Amundson, P.I.; Goin, R.W.; Webster, D.S.

1980-01-01

The results of the FBR fuel cycle study that supported US contributions to the INFCE are presented. Fuel cycle technology is reviewed from both generic and historical standpoints. Technology requirements are developed within the framework of three deployment scenarios: the reference international, the secured area, and the integral cycle. Reprocessing, fabrication, waste handling, transportation, and safeguards are discussed for each deployment scenario. Fuel cycle modifications designed to increase proliferation defenses are described and assessed for effectiveness and technology feasibility. The present status of fuel cycle technology is reviewed and key issues that require resolution are identified

Cell-cycle synchronisation of bloodstream forms of Trypanosoma brucei using Vybrant DyeCycle Violet-based sorting.

Science.gov (United States)

Kabani, Sarah; Waterfall, Martin; Matthews, Keith R

2010-01-01

Studies on the cell-cycle of Trypanosoma brucei have revealed several unusual characteristics that differ from the model eukaryotic organisms. However, the inability to isolate homogenous populations of parasites in distinct cell-cycle stages has limited the analysis of trypanosome cell division and complicated the understanding of mutant phenotypes with possible impact on cell-cycle related events. Although hydroxyurea-induced cell-cycle arrest in procyclic and bloodstream forms has been applied recently with success, such block-release protocols can complicate the analysis of cell-cycle regulated events and have the potential to disrupt important cell-cycle checkpoints. An alternative approach based on flow cytometry of parasites stained with Vybrant DyeCycle Orange circumvents this problem, but is restricted to procyclic form parasites. Here, we apply Vybrant Dyecycle Violet staining coupled with flow cytometry to effectively select different cell-cycle stages of bloodstream form trypanosomes. Moreover, the sorted parasites remain viable, although synchrony is rapidly lost. This method enables cell-cycle enrichment of populations of trypanosomes in their mammal infective stage, particularly at the G1 phase.

Fast breeder fuel cycle

International Nuclear Information System (INIS)

1978-09-01

Basic elements of the ex-reactor part of the fuel cycle (reprocessing, fabrication, waste handling and transportation) are described. Possible technical and proliferation measures are evaluated, including current methods of accountability, surveillance and protection. The reference oxide based cycle and advanced cycles based on carbide and metallic fuels are considered utilizing conventional processes; advanced nonaqueous reprocessing is also considered. This contribution provides a comprehensive data base for evaluation of proliferation risks

Advanced fuel cycles: a rationale and strategy for adopting the low-enriched-uranium fuel cycle

International Nuclear Information System (INIS)

James, R.A.

1980-01-01

A two-year study of alternatives to the natural uranium fuel cycle in CANDU reactors is summarized. The possible advanced cycles are briefly described. Selection criteria for choosing a cycle for development include resource utilization, economics, ease of implementaton, and social acceptability. It is recommended that a detailed study should be made with a view to the early implementation of the low-enriched uranium cycle. (LL)

Extended trigonometric Cherednik algebras and nonstationary Schrödinger equations with delta-potentials

International Nuclear Information System (INIS)

Hartwig, J. T.; Stokman, J. V.

2013-01-01

We realize an extended version of the trigonometric Cherednik algebra as affine Dunkl operators involving Heaviside functions. We use the quadratic Casimir element of the extended trigonometric Cherednik algebra to define an explicit nonstationary Schrödinger equation with delta-potential. We use coordinate Bethe ansatz methods to construct solutions of the nonstationary Schrödinger equation in terms of generalized Bethe wave functions. It is shown that the generalized Bethe wave functions satisfy affine difference Knizhnik-Zamolodchikov equations as functions of the momenta. The relation to the vector valued root system analogs of the quantum Bose gas on the circle with delta-function interactions is indicated.

Yang-Yang method for the thermodynamics of one-dimensional multi-component interacting fermions

International Nuclear Information System (INIS)

Lee, J Y; Guan, X W; Batchelor, M T

2011-01-01

Using Yang and Yang's particle-hole description, we present a thorough derivation of the thermodynamic Bethe ansatz equations for a general SU(κ) fermionic system in one dimension for both the repulsive and attractive regimes under the presence of an external magnetic field. These equations are derived from Sutherland's Bethe ansatz equations by using the spin-string hypothesis. The Bethe ansatz root patterns for the attractive case are discussed in detail. The relationship between the various phases of the magnetic phase diagrams and the external magnetic fields is given for the attractive case. We also give a quantitative description of the ground-state energies for both strongly repulsive and attractive regimes.

Cell Cycle Control by PTEN.

Science.gov (United States)

Brandmaier, Andrew; Hou, Sheng-Qi; Shen, Wen H

2017-07-21

Continuous and error-free chromosome inheritance through the cell cycle is essential for genomic stability and tumor suppression. However, accumulation of aberrant genetic materials often causes the cell cycle to go awry, leading to malignant transformation. In response to genotoxic stress, cells employ diverse adaptive mechanisms to halt or exit the cell cycle temporarily or permanently. The intrinsic machinery of cycling, resting, and exiting shapes the cellular response to extrinsic stimuli, whereas prevalent disruption of the cell cycle machinery in tumor cells often confers resistance to anticancer therapy. Phosphatase and tensin homolog (PTEN) is a tumor suppressor and a guardian of the genome that is frequently mutated or deleted in human cancer. Moreover, it is increasingly evident that PTEN deficiency disrupts the fundamental processes of genetic transmission. Cells lacking PTEN exhibit cell cycle deregulation and cell fate reprogramming. Here, we review the role of PTEN in regulating the key processes in and out of cell cycle to optimize genomic integrity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Menstrual cycle pattern and fertility

DEFF Research Database (Denmark)

Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

1999-01-01

OBJECTIVE: To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss. DESIGN: Prospective follow-up study. SETTING: Healthy couples recruited throughout Denmark....... PATIENT(S): Two hundred ninety-five couples who were planning their first pregnancy were followed up from the discontinuation of birth control until a pregnancy was recognized within six menstrual cycles. Early embryonal losses were detected by changes in urinary hCG levels. INTERVENTION(S): None. MAIN...... OUTCOME MEASURE(S): The probability of pregnancy occurring within one menstrual cycle (fecundity). RESULT(S): In women who had a cycle length that differed by >10 days from the usual cycle length, fecundity was approximately 25% that of women who had no variation (odds ratio 0.25, 95% confidence interval...

National Policy on Nuclear Fuel Cycle

International Nuclear Information System (INIS)

Soedyartomo, S.

1996-01-01

National policy on nuclear fuel cycle is aimed at attaining the expected condition, i.e. being able to support optimality the national energy policy and other related Government policies taking into account current domestic nuclear fuel cycle condition and the trend of international nuclear fuel cycle development, the national strength, weakness, thread and opportunity in the field of energy. This policy has to be followed by the strategy to accomplish covering the optimization of domestic efforts, cooperation with other countries, and or purchasing licences. These policy and strategy have to be broken down into various nuclear fuel cycle programmes covering basically assesment of the whole cycle, performing research and development of the whole cycle without enrichment and reprocessing being able for weapon, as well as programmes for industrialization of the fuel cycle stepwisery commencing with the middle part of the cycle and ending with the edge of the back-end of the cycle

Rock Cycle Roulette.

Science.gov (United States)

Schmidt, Stan M.; Palmer, Courtney

2000-01-01

Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

[Effects and mechanism of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem].

Science.gov (United States)

Wang, Li-qin; Qi, Yu-chun; Dong, Yun-she; Peng, Qin; Guo, Shu-fang; He, Yun-long; Yan, Zhong-qing

2015-11-01

As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.

Associations between Recreational and Commuter Cycling, Changes in Cycling, and Type 2 Diabetes Risk

DEFF Research Database (Denmark)

Rasmussen, Martin G; Grøntved, Anders; Blond, Kim

2016-01-01

BACKGROUND: Cycling is a recreational activity and mode of commuting with substantial potential to improve public health in many countries around the world. The aim of this study was to examine prospective associations between recreational and commuter cycling, changes in cycling habits, and risk.......83 (0.69, 1.00), and 0.70 (0.57, 0.85) (p for trend = 150 min/wk to work, respectively. The main limitation of the current study is the use of self-reported physical activity. CONCLUSIONS: Commuter and recreational cycling was consistently associated with lower...

Transportation life cycle assessment (LCA) synthesis : life cycle assessment learning module series.

Science.gov (United States)

2015-03-12

The Life Cycle Assessment Learning Module Series is a set of narrated, self-advancing slideshows on : various topics related to environmental life cycle assessment (LCA). This research project produced the first 27 of such modules, which : are freely...

Large-scale fuel cycle centres

International Nuclear Information System (INIS)

Smiley, S.H.; Black, K.M.

1977-01-01

The US Nuclear Regulatory Commission (NRC) has considered the nuclear energy centre concept for fuel cycle plants in the Nuclear Energy Centre Site Survey 1975 (NECSS-75) Rep. No. NUREG-0001, an important study mandated by the US Congress in the Energy Reorganization Act of 1974 which created the NRC. For this study, the NRC defined fuel cycle centres as consisting of fuel reprocessing and mixed-oxide fuel fabrication plants, and optional high-level waste and transuranic waste management facilities. A range of fuel cycle centre sizes corresponded to the fuel throughput of power plants with a total capacity of 50,000-300,000MW(e). The types of fuel cycle facilities located at the fuel cycle centre permit the assessment of the role of fuel cycle centres in enhancing the safeguard of strategic special nuclear materials - plutonium and mixed oxides. Siting fuel cycle centres presents a smaller problem than siting reactors. A single reprocessing plant of the scale projected for use in the USA (1500-2000t/a) can reprocess fuel from reactors producing 50,000-65,000MW(e). Only two or three fuel cycle centres of the upper limit size considered in the NECSS-75 would be required in the USA by the year 2000. The NECSS-75 fuel cycle centre evaluation showed that large-scale fuel cycle centres present no real technical siting difficulties from a radiological effluent and safety standpoint. Some construction economies may be achievable with fuel cycle centres, which offer opportunities to improve waste-management systems. Combined centres consisting of reactors and fuel reprocessing and mixed-oxide fuel fabrication plants were also studied in the NECSS. Such centres can eliminate shipment not only of Pu but also mixed-oxide fuel. Increased fuel cycle costs result from implementation of combined centres unless the fuel reprocessing plants are commercial-sized. Development of Pu-burning reactors could reduce any economic penalties of combined centres. The need for effective fissile

Economic comparison of fusion fuel cycles

International Nuclear Information System (INIS)

Brereton, S.J.; Kazimi, M.S.

1987-01-01

The economics of the DT, DD, and DHe fusion fuel cycles are evaluated by comparison on a consistent basis. The designs for the comparison employ HT-9 structure and helium coolant; liquid lithium is used as the tritium breeding material for the DT fuel cycle. The reactors are pulsed, superconducting tokamaks, producing 1200 MW of electric power. The DT and DD designs scan a range of values of plasma beta, assuming first stability scaling laws. The results indicate that on a purely economic basis, the DT fuel cycle is superior to both of the advanced fuel cycles. Geometric factors, materials limitations, and plasma beta were seen to have an impact on the Cost of Electricity (COE). The economics for the DD fuel cycle are more strongly affected by these parameters than is the DT fuel cycle. Fuel costs are a major factor in determining the COE for the DHe fuel cycle. Based on costs directly attributable to the fuel cycle, the DT fuel cycle appears most attractive. Technological advances, improved understanding of physics, or strides in advanced energy conversion schemes may result in altering the economic ranking of the fuel cycles indicated here. 7 refs., 6 figs., 2 tabs

Cycle layout studies of S-CO2 cycle for the next generation nuclear system application

International Nuclear Information System (INIS)

Ahn, Yoonhan; Bae, Seong Jun; Kim, Minseok; Cho, Seong Kuk; Baik, Seungjoon; Lee, Jeong Ik; Cha, Jae Eun

2014-01-01

According to the second law of thermodynamics, the next generation nuclear reactor system efficiency can potentially be increased with higher operating temperature. Fig.1 shows several power conversion system efficiencies and heat sources with respect to the system top operating temperature. As shown in Fig.1, the steam Rankine and gas Brayton cycles have been considered as the major power conversion systems more than several decades. In the next generation reactor operating temperature region (450 - 900 .deg. C), the steam Rankine and gas Brayton cycles have limits due to material problems and low efficiency, respectively. Among the future power conversion systems, S-CO 2 cycle is receiving interests due to several benefits including high efficiency under the mild turbine inlet temperature range (450-650 .deg. C), compact turbomachinery and simple layout compared to the steam Rankine cycle. S-CO 2 cycle can show relatively high efficiency under the mild turbine inlet temperature range (450-600 .deg. C) compared to other power conversion systems. The recompression cycle shows the best efficiency among other layouts and it is suitable for the application to advanced nuclear reactor systems. As S-CO 2 cycle performance can vary depending on the layout configuration, further studies on the layouts are required to design a better performing cycle

The Life Cycle of Centrioles

OpenAIRE

Hatch, E.; Stearns, T.

2010-01-01

Centrioles organize the centrosome and nucleate the ciliary axoneme, and the centriole life cycle has many parallels to the chromosome cycle. The centriole cycle in animals begins at fertilization with the contribution of two centrioles by the male gamete. In the ensuing cell cycles, the duplication of centrioles is controlled temporally, spatially, and numerically. As a consequence of the duplication mechanism, the two centrioles in a typical interphase cell are of different ages and have di...

Gas fired combined cycle plant in Singapore: energy use, GWP and cost-a life cycle approach

International Nuclear Information System (INIS)

Kannan, R.; Leong, K.C.; Osman, Ramli; Ho, H.K.; Tso, C.P.

2005-01-01

A life cycle assessment was performed to quantify the non-renewable (fossil) energy use and global warming potential (GWP) in electricity generation from a typical gas fired combined cycle power plant in Singapore. The cost of electricity generation was estimated using a life cycle cost analysis (LCCA) tool. The life cycle assessment (LCA) of a 367.5 MW gas fired combined cycle power plant operating in Singapore revealed that hidden processes consume about 8% additional energy in addition to the fuel embedded energy, and the hidden GWP is about 18%. The natural gas consumed during the operational phase accounted for 82% of the life cycle cost of electricity generation. An empirical relation between plant efficiency and life cycle energy use and GWP in addition to a scenario for electricity cost with varying gas prices and plant efficiency have been established

In anticipation of cycle 24

Science.gov (United States)

Kunches, Joseph; van der Linden, Ronald; Lundstedt, Henrik

Anxious eyes are watching for the beginnings of new solar cycle 24. The watchers are many; scientists, engineers, academics, forecasters, end users. Their needs however vary, from the attraction of a better understanding of our nearest star, to how its increase in luminosity will affect particular aspects such as satellite orbits or the strength of the episodic storms that are most likely to occur during the height of the cycle. The first sign, however fleeting, occurred in January, 2008, when an ephemeral new cycle spot was numbered by NOAA as 10981. It was gone quickly but did mark the possible beginning of the new cycle. There has been great debate among solar physicists on how strong cycle 24 will be; and when it will start, reach maximum, and decline. This talk will give the status of the efforts to predict cycle 24, and the most recent projections.

The economics of thorium fuel cycles

International Nuclear Information System (INIS)

James, R.A.

1978-01-01

The individual cost components and the total fuel cycle costs for natural uranium and thorium fuel cycles are discussed. The thorium cycles are initiated by using either enriched uranium or plutonium. Subsequent thorium cycles utilize recycled uranium-233 and, where necessary, either uranium-235 or plutonium as topping. A calculation is performed to establish the economic conditions under which thorium cycles are economically attractive. (auth)

Limit cycles in quantum systems

Energy Technology Data Exchange (ETDEWEB)

Niemann, Patrick

2015-04-27

In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

The nuclear fuel cycle versus the carbon cycle

International Nuclear Information System (INIS)

Ewing, R.C.

2005-01-01

Nuclear power provides approximately 17% of the world's electricity, which is equivalent to a reduction in carbon emissions of ∼0.5 gigatonnes (Gt) of C/yr. This is a modest reduction as compared with global emissions of carbon, ∼7 Gt C/yr. Most analyses suggest that in order to have a significant and timely impact on carbon emissions, carbon-free sources, such as nuclear power, would have to expand total production of energy by factors of three to ten by 2050. A three-fold increase in nuclear power capacity would result in a projected reduction in carbon emissions of 1 to 2 Gt C/yr, depending on the type of carbon-based energy source that is displaced. This three-fold increase utilizing present nuclear technologies would result in 25,000 metric tonnes (t) of spent nuclear fuel (SNF) per year, containing over 200 t of plutonium. This is compared to a present global inventory of approximately 280,000 t of SNF and >1,700 t of Pu. A nuclear weapon can be fashioned from as little as 5 kg of 239 Pu. However, there is considerable technological flexibility in the nuclear fuel cycle. There are three types of nuclear fuel cycles that might be utilized for the increased production of energy: open, closed, or a symbiotic combination of different types of reactor (such as, thermal and fast neutron reactors). The neutron energy spectrum has a significant effect on the fission product yield, and the consumption of long-lived actinides, by fission, is best achieved by fast neutrons. Within each cycle, the volume and composition of the high-level nuclear waste and fissile material depend on the type of nuclear fuel, the amount of burn-up, the extent of radionuclide separation during reprocessing, and the types of materials used to immobilize different radionuclides. As an example, a 232 Th-based fuel cycle can be used to breed fissile 233 U with minimum production of Pu. In this paper, I will contrast the production of excess carbon in the form of CO 2 from fossil fuels with

Measuring Business Cycle Time.

OpenAIRE

Stock, James H

1987-01-01

The business cycle analysis of Arthur F. Burns and Wesley C. Mitchell and the National Bureau of Economic Research presumed that aggregate economic variables evolve on a time scale defined by business cycle turning points rather than by months or quarters. Do macroeconomic variables appear to evolve on an economic rather than a calendar time scale? Evidence presented here suggests that they do. However, the estimated economic time scales are only weakly related to business cycle time scales, ...

Power generation from a 7700C heat source by means of a main steam cycle, a topping closed gas cycle and a ammonia bottoming cycle

International Nuclear Information System (INIS)

Tilliette, Z.P.

1981-03-01

For power generation, steam cycles make an efficient use of medium temperature heat sources. They can be adapted to dry cooling, higher power ratings and output increase in winter by addition of an ammonia bottoming cycle. Active development is carried out in this field by 'Electricite de France'. As far as heat sources at higher temperatures are concerned, particularly related to coal-fired or nuclear power plants, a more efficient way of converting energy is at first to expand a hot working fluid through a gas turbine. It is shown in this paper that a satisfactory result, for heat sources of about 770 0 C, is obtained with a topping closed gas cycle of moderate power rating, rejecting its waste heat into the main steam cycle. Attention has to be paid to this gas cycle waste heat recovery and to the coupling of the gas and steam cycles. This concept drastically reduces the importance of new technology components. The use and the significance of an ammonia bottoming cycle in this case are investigated

Entrepreneurship and the Business Cycle

NARCIS (Netherlands)

Ph.D. Koellinger (Philipp); A.R. Thurik (Roy)

2011-01-01

textabstractWe find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972-2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment

Quadratic reactivity fuel cycle model

International Nuclear Information System (INIS)

Lewins, J.D.

1985-01-01

For educational purposes it is highly desirable to provide simple yet realistic models for fuel cycle and fuel economy. In particular, a lumped model without recourse to detailed spatial calculations would be very helpful in providing the student with a proper understanding of the purposes of fuel cycle calculations. A teaching model for fuel cycle studies based on a lumped model assuming the summability of partial reactivities with a linear dependence of reactivity usefully illustrates fuel utilization concepts. The linear burnup model does not satisfactorily represent natural enrichment reactors. A better model, showing the trend of initial plutonium production before subsequent fuel burnup and fission product generation, is a quadratic fit. The study of M-batch cycles, reloading 1/Mth of the core at end of cycle, is now complicated by nonlinear equations. A complete account of the asymptotic cycle for any order of M-batch refueling can be given and compared with the linear model. A complete account of the transient cycle can be obtained readily in the two-batch model and this exact solution would be useful in verifying numerical marching models. It is convenient to treat the parabolic fit rho = 1 - tau 2 as a special case of the general quadratic fit rho = 1 - C/sub tau/ - (1 - C)tau 2 in suitably normalized reactivity and cycle time units. The parabolic results are given in this paper

Historicising the Hydrosocial Cycle

Directory of Open Access Journals (Sweden)

Jeremy J. Schmidt

2014-02-01

Full Text Available This paper examines the historical claims made in support of the hydrosocial cycle. In particular, it considers how arguments advancing the hydrosocial cycle make historical claims regarding modernist conceptions of what water is (i.e. H2O and its fit with society. The paper gives special emphasis to the society/nature dualism and to the notion of agency as key sites of contest in arguments regarding the hydrosocial cycle. It finds that, while several versions of the hydrosocial cycle seek to advance a political ecology more sensitive to non-human actions, these same accounts often do not address the robust account of non-human agency in the historical record. Evidence is presented regarding water’s agency amongst late 19th and early 20th century architects of key water management norms in the United States. This evidence troubles accounts of the hydrosocial cycle that critique the US experience and suggests new directions for rethinking the role of historical and institutional norms in water policy.

Combined rankine and vapor compression cycles

Science.gov (United States)

Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

2005-04-19

An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

Life cycle assessment (LCA)

DEFF Research Database (Denmark)

Thrane, Mikkel; Schmidt, Jannick Andresen

2004-01-01

The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards.......The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards....

Cycling biomechanics: a literature review.

Science.gov (United States)

Wozniak Timmer, C A

1991-01-01

Submitted in partial fulfillment for a Master of Science degree at the University of Pittsburgh, School of Health Related Professions, Pittsburgh, PA 1.5213 This review of current literature on cycling biomechanics emphasizes lower extremity muscle actions and joint excursions, seat height, pedal position, pedaling rate, force application, and pedaling symmetry. Guidelines are discussed for optimal seat height, pedal position, and pedaling rate. Force application in the power and recovery phases of cycling and the relationship of force application to pedaling symmetry are discussed. The need for a biomechanical approach to cycling exists since a great deal of the literature is primarily physiologic in nature. The purpose of this review is to make cyclists and their advisors aware of the biomechanics of cycling and guidelines to follow. This approach is also important because cycling is a very common form of exercise prescribed by physical therapists for clinic or home programs. Biomechanical aspects of cycling should be considered by cyclists at any level of participation and by physical therapists in order for goal-oriented, efficient cycling to occur. J Orthop Sports Phys Ther 1991;14(3):106-113.

Thorium fuel cycle analysis

Energy Technology Data Exchange (ETDEWEB)

Yamaji, K [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

1980-07-01

Systems analysis of the thorium cycle, a nuclear fuel cycle accomplished by using thorium, is reported in this paper. Following a brief review on the history of the thorium cycle development, analysis is made on the three functions of the thorium cycle; (1) auxiliary system of U-Pu cycle to save uranium consumption, (2) thermal breeder system to exert full capacity of the thorium resource, (3) symbiotic system to utilize special features of /sup 233/U and neutron sources. The effects of the thorium loading in LWR (Light Water Reactor), HWR (Heavy Water Reactor) and HTGR (High Temperature Gas-cooled Reactor) are considered for the function of auxiliary system of U-Pu cycle. Analysis is made to find how much uranium is saved by /sup 233/U recycling and how the decrease in Pu production influences the introduction of FBR (Fast Breeder Reactor). Study on thermal breeder system is carried out in the case of MSBR (Molten Salt Breeder Reactor). Under a certain amount of fissile material supply, the potential system expansion rate of MSBR, which is determined by fissile material balance, is superior to that of FBR because of the smaller specific fissile inventory of MSBR. For symbiotic system, three cases are treated; i) nuclear heat supply system using HTGR, ii) denatured fuel supply system for nonproliferation purpose, and iii) hybrid system utilizing neutron sources other than fission reactor.

International Business Cycle Accounting

OpenAIRE

Keisuke Otsu

2009-01-01

In this paper, I extend the business cycle accounting method a la Chari, Kehoe and McGrattan (2007) to a two-country international business cycle model and quantify the effect of the disturbances in relevant markets on the business cycle correlation between Japan and the US over the 1980-2008 period. This paper finds that disturbances in the labor market and production efficiency are important in accounting for the recent increase in the cross-country output correlation. If international fina...

Optimal Life Cycle Portfolio Choice with Housing Market Cycles

DEFF Research Database (Denmark)

Fischer, Marcel; Stamos, Michael Z.

2013-01-01

income, and pre-existing housing wealth but also the state of the housing market significantly affect household decisions. Consistently with the data, the model predicts that in good states of housing market cycles (1) homeownership rates increase, (2) households buying homes invest a larger share......In recent decades U.S. households have experienced residential house prices moving persistently, that is, returns being positively serially correlated. We set up a realistically calibrated life cycle model with slow-moving time variation in expected housing returns, showing that not only age, labor...

Large-scale fuel cycle centers

International Nuclear Information System (INIS)

Smiley, S.H.; Black, K.M.

1977-01-01

The United States Nuclear Regulatory Commission (NRC) has considered the nuclear energy center concept for fuel cycle plants in the Nuclear Energy Center Site Survey - 1975 (NECSS-75) -- an important study mandated by the U.S. Congress in the Energy Reorganization Act of 1974 which created the NRC. For the study, NRC defined fuel cycle centers to consist of fuel reprocessing and mixed oxide fuel fabrication plants, and optional high-level waste and transuranic waste management facilities. A range of fuel cycle center sizes corresponded to the fuel throughput of power plants with a total capacity of 50,000 - 300,000 MWe. The types of fuel cycle facilities located at the fuel cycle center permit the assessment of the role of fuel cycle centers in enhancing safeguarding of strategic special nuclear materials -- plutonium and mixed oxides. Siting of fuel cycle centers presents a considerably smaller problem than the siting of reactors. A single reprocessing plant of the scale projected for use in the United States (1500-2000 MT/yr) can reprocess the fuel from reactors producing 50,000-65,000 MWe. Only two or three fuel cycle centers of the upper limit size considered in the NECSS-75 would be required in the United States by the year 2000 . The NECSS-75 fuel cycle center evaluations showed that large scale fuel cycle centers present no real technical difficulties in siting from a radiological effluent and safety standpoint. Some construction economies may be attainable with fuel cycle centers; such centers offer opportunities for improved waste management systems. Combined centers consisting of reactors and fuel reprocessing and mixed oxide fuel fabrication plants were also studied in the NECSS. Such centers can eliminate not only shipment of plutonium, but also mixed oxide fuel. Increased fuel cycle costs result from implementation of combined centers unless the fuel reprocessing plants are commercial-sized. Development of plutonium-burning reactors could reduce any

Fuel cycle optimization in PWR'S

International Nuclear Information System (INIS)

Castro Lobo, P.D. de; Amorim, E.S. do.

1979-08-01

Neutronics aspects of a reactor core throughout its cycle were investigated in a search for increasing in-core utilization of the residual fissile isotopes content in the cycle discharged disposal. The effects due to design modifications introduced at burnup levels near the end-of-cycle, in an equilibrium cycle condition, have indicated the possibility of a better in-core utilization of the residual fissile isotopes existing in the cycle discharged disposal. The potential benefits are significant to warranty an examination of the mechanical and thermal hydraulic involved. At convenient burnup levels, change in H 2 O/UO 2 volume ratio were introduced allowing an intense depletion of the residual fissile isotopes existing in assemblies with high exposures levels. (Author) [pt

Gender differences in recreational and transport cycling: a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints.

Science.gov (United States)

Heesch, Kristiann C; Sahlqvist, Shannon; Garrard, Jan

2012-09-08

Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and in motivators and constraints to cycling, separately for recreational and transport cycling. Adult members of a Queensland, Australia, community bicycling organization completed an online survey about their cycling patterns; cycling purposes; and personal, social and perceived environmental motivators and constraints (47% response rate). Closed and open-end questions were completed. Using the quantitative data, multivariable linear, logistic and ordinal regression models were used to examine associations between gender and cycling patterns, motivators and constraints. The qualitative data were thematically analyzed to expand upon the quantitative findings. In this sample of 1862 bicyclists, men were more likely than women to cycle for recreation and for transport, and they cycled for longer. Most transport cycling was for commuting, with men more likely than women to commute by bicycle. Men were more likely to cycle on-road, and women off-road. However, most men and women did not prefer to cycle on-road without designed bicycle lanes, and qualitative data indicated a strong preference by men and women for bicycle-only off-road paths. Both genders reported personal factors (health and enjoyment related) as motivators for cycling, although women were more likely to agree that other personal, social and environmental factors were also motivating. The main constraints for both genders and both cycling purposes were perceived environmental factors related to traffic conditions, motorist aggression and

Cycle-by-cycle variations in a spark ignition engine fueled with natural gas-hydrogen blends combined with EGR

Energy Technology Data Exchange (ETDEWEB)

Huang, Bin; Hu, Erjiang; Huang, Zuohua; Zheng, Jianjun; Liu, Bing; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, 710049 Xi' an (China)

2009-10-15

Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas-hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak pressure, the maximum rate of pressure rise and the indicated mean effective pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated mean effective pressure and EGR ratio. Slight influence of EGR ratio on indicated mean effective pressure is observed at low EGR ratios while large influence of EGR ratio on indicated mean effective pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios. (author)

Interventions to promote cycling: systematic review.

Science.gov (United States)

Yang, Lin; Sahlqvist, Shannon; McMinn, Alison; Griffin, Simon J; Ogilvie, David

2010-10-18

To determine what interventions are effective in promoting cycling, the size of the effects of interventions, and evidence of any associated benefits on overall physical activity or anthropometric measures. Systematic review. Published and unpublished reports in any language identified by searching 13 electronic databases, websites, reference lists, and existing systematic reviews, and papers identified by experts in the field. Review methods Controlled "before and after" experimental or observational studies of the effect of any type of intervention on cycling behaviour measured at either individual or population level. Twenty five studies (of which two were randomised controlled trials) from seven countries were included. Six studies examined interventions aimed specifically at promoting cycling, of which four (an intensive individual intervention in obese women, high quality improvements to a cycle route network, and two multifaceted cycle promotion initiatives at town or city level) were found to be associated with increases in cycling. Those studies that evaluated interventions at population level reported net increases of up to 3.4 percentage points in the population prevalence of cycling or the proportion of trips made by bicycle. Sixteen studies assessing individualised marketing of "environmentally friendly" modes of transport to interested households reported modest but consistent net effects equating to an average of eight additional cycling trips per person per year in the local population. Other interventions that targeted travel behaviour in general were not associated with a clear increase in cycling. Only two studies assessed effects of interventions on physical activity; one reported a positive shift in the population distribution of overall physical activity during the intervention. Community-wide promotional activities and improving infrastructure for cycling have the potential to increase cycling by modest amounts, but further controlled

Exact solutions of sl-boson system in U(2l + 1) reversible O(2l + 2) transitional region

CERN Document Server

Zhang Xin

2002-01-01

Exact eigen-energies and the corresponding wavefunctions of the interacting sl-boson system in U(2l + 1) reversible O(2l +2) transitional region are obtained by using an algebraic Bethe Ansatz with the infinite dimensional Lie algebraic technique. Numerical algorithm for solving the Bethe Ansatz equations by using mathematical package is also outlined

Effect of irreversible processes on the thermodynamic performance of open-cycle desiccant cooling cycles

International Nuclear Information System (INIS)

La, Dong; Li, Yong; Dai, Yanjun; Ge, Tianshu; Wang, Ruzhu

2013-01-01

Highlights: ► Effects of irreversible processes on the performance of desiccant cooling cycle are identified. ► The exergy destructions involved are classified by the properties of the individual processes. ► Appropriate indexes for thermodynamic evaluation are proposed based on thermodynamic analyses. - Abstract: Thermodynamic analyses of desiccant cooling cycle usually focus on the overall cycle performance in previous study. In this paper, the effects of the individual irreversible processes in each component on thermodynamic performance are analyzed in detail. The objective of this paper is to reveal the elemental features of the individual components, and to show their effects on the thermodynamic performance of the whole cycle in a fundamental way. Appropriate indexes for thermodynamic evaluation are derived based on the first and second law analyses. A generalized model independent of the connection of components is developed. The results indicate that as the effectiveness of the desiccant wheel increases, the cycle performance is increased principally due to the significant reduction in exergy carried out by exhaust air. The corresponding exergy destruction coefficient of the cycle with moderate performance desiccant wheel is decreased greatly to 3.9%, which is more than 50% lower than that of the cycle with low performance desiccant wheel. The effect of the heat source is similar. As the temperature of the heat source increases from 60 °C to 90 °C, the percentage of exergy destruction raised by exhaust air increases sharply from 5.3% to 21.8%. High heat exchanger effectiveness improves the cycle performance mainly by lowering the irreversibility of the heat exchanger, using less regeneration heat and pre-cooling the process air effectively

Life Cycle Sustainability Dashboard

DEFF Research Database (Denmark)

Traverso, Marzia; Finkbeiner, Matthias; Jørgensen, Andreas

2012-01-01

One method to assess the sustainability performance of products is life cycle sustainability assessment (LCSA), which assesses product performance considering the environmental,economic, and social dimensions of the life cycle. The results of LCSA can be used to compare different products...... of sustainability is the communicability of the results by means of a graphical representation (a cartogram), characterized by a suitable chromatic scale and ranking score. The integration of LCSA and the dashboard of sustainability into a so-called Life Cycle Sustainability Dashboard (LCSD) is described here...

Assessing the impact of road traffic on cycling for leisure and cycling to work

Directory of Open Access Journals (Sweden)

Wareham Nicholas J

2011-06-01

Full Text Available Abstract Background To explore the relationship between leisure and commuter cycling with objectively measured levels of road traffic and whether any relationship was affected by traffic levels directly outside of home or in local neighbourhood. Findings We conducted a secondary analysis of data from the UK European Prospective Investigation of Cancer (EPIC Norfolk cohort in 2009. We used a geographical information system (GIS and gender specific multivariate models to relate 13 927 participants' reported levels of cycling with an index of road traffic volume (Road Traffic Volume Index Score - RTVIS. RTVIS were calculated around each participants home, using four distance based buffers, (0.5 km, 1 km, 2 km and 3.2 km. Models were adjusted for age, social status, education, car access and deprivation. Both genders had similar decreases in leisure cycling as traffic volumes increased at greater distances from home (OR 0.42, (95% CI 0.32-0.52, p Conclusions Traffic volumes appear to have greater impact on leisure cycling than commuter cycling. Future research should investigate the importance of traffic on different types of cycling and include psychosocial correlates.

Frozen-Thawed Embryo Transfer Cycles Have a Lower Incidence of Ectopic Pregnancy Compared With Fresh Embryo Transfer Cycles.

Science.gov (United States)

Zhang, Xinyu; Ma, Caihong; Wu, Zhangxin; Tao, Liyuan; Li, Rong; Liu, Ping; Qiao, Jie

2017-01-01

To evaluate the risk of ectopic pregnancy of embryo transfer. A retrospective cohort study on the incidence of ectopic pregnancy in fresh and frozen-thawed embryo transfer cycles from January 1 st , 2010, to January 1 st , 2015. Infertile women undergoing frozen-thawed transfer cycles or fresh transfer cycles. In-vitro fertilization, fresh embryo transfer, frozen-thawed embryo transfer, ectopic pregnancy. Ectopic pregnancy rate and clinical pregnancy rate. A total of 69 756 in vitro fertilization-embryo transfer cycles from 2010 to 2015 were analyzed, including 45 960 (65.9%) fresh and 23 796 (34.1%) frozen-thawed embryo transfer cycles. The clinical pregnancy rate per embryo transfer was slightly lower in fresh embryo transfer cycles compared with frozen-thawed embryo transfer cycles (40.8% vs 43.1%, P cycles, blastocyst transfer shows a significantly lower incidence of ectopic pregnancy (0.8% vs 1.8%, P = .002) in comparison with day 3 cleavage embryo transfer. The risk of ectopic pregnancy is lower in frozen-thawed embryo transfer cycles than fresh embryo transfer cycles, and blastocyst transfer could further decrease the ectopic pregnancy rate in frozen-thawed embryo transfer cycles.

Research on Correlation between Vehicle Cycle and Engine Cycle in Heavy-duty commercial vehicle

Science.gov (United States)

lin, Chen; Zhong, Wang; Shuai, Liu

2017-12-01

In order to study the correlation between vehicle cycle and engine cycle in heavy commercial vehicles, the conversion model of vehicle cycle to engine cycle is constructed based on the vehicle power system theory and shift strategy, which considers the verification on diesel truck. The results show that the model has high rationality and reliability in engine operation. In the acceleration process of high speed, the difference of model gear selection leads to the actual deviation. Compared with the drum test, the engine speed distribution obtained by the model deviates to right, which fits to the lower grade. The grade selection has high influence on the model.

Thorium fuel cycle management

International Nuclear Information System (INIS)

Zajac, R.; Darilek, P.; Breza, J.; Necas, V.

2010-01-01

In this presentation author deals with the thorium fuel cycle management. Description of the thorium fuels and thorium fuel cycle benefits and challenges as well as thorium fuel calculations performed by the computer code HELIOS are presented.

Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle

Directory of Open Access Journals (Sweden)

Lingen Chen

2012-01-01

Full Text Available A thermodynamic model of an open combined regenerative Brayton and inverse Brayton cycles with regeneration before the inverse cycle is established in this paper by using thermodynamic optimization theory. The flow processes of the working fluid with the pressure drops and the size constraint of the real power plant are modeled. There are 13 flow resistances encountered by the working fluid stream for the cycle model. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining nine flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, regenerator inlet and outlet, combustion chamber inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle, and control the air flow rate, the net power output and the thermal efficiency. The analytical formulae about the power output, efficiency and other coefficients are derived with 13 pressure drop losses. It is found that the combined cycle with regenerator can reach higher thermal efficiency but smaller power output than those of the base combined cycle at small compressor inlet relative pressure drop of the top cycle.

Nitrogen Cycle Evaluation (NiCE) Chip for the Simultaneous Analysis of Multiple N-Cycle Associated Genes.

Science.gov (United States)

Oshiki, Mamoru; Segawa, Takahiro; Ishii, Satoshi

2018-02-02

Various microorganisms play key roles in the Nitrogen (N) cycle. Quantitative PCR (qPCR) and PCR-amplicon sequencing of the N cycle functional genes allow us to analyze the abundance and diversity of microbes responsible in the N transforming reactions in various environmental samples. However, analysis of multiple target genes can be cumbersome and expensive. PCR-independent analysis, such as metagenomics and metatranscriptomics, is useful but expensive especially when we analyze multiple samples and try to detect N cycle functional genes present at relatively low abundance. Here, we present the application of microfluidic qPCR chip technology to simultaneously quantify and prepare amplicon sequence libraries for multiple N cycle functional genes as well as taxon-specific 16S rRNA gene markers for many samples. This approach, named as N cycle evaluation (NiCE) chip, was evaluated by using DNA from pure and artificially mixed bacterial cultures and by comparing the results with those obtained by conventional qPCR and amplicon sequencing methods. Quantitative results obtained by the NiCE chip were comparable to those obtained by conventional qPCR. In addition, the NiCE chip was successfully applied to examine abundance and diversity of N cycle functional genes in wastewater samples. Although non-specific amplification was detected on the NiCE chip, this could be overcome by optimizing the primer sequences in the future. As the NiCE chip can provide high-throughput format to quantify and prepare sequence libraries for multiple N cycle functional genes, this tool should advance our ability to explore N cycling in various samples. Importance. We report a novel approach, namely Nitrogen Cycle Evaluation (NiCE) chip by using microfluidic qPCR chip technology. By sequencing the amplicons recovered from the NiCE chip, we can assess diversities of the N cycle functional genes. The NiCE chip technology is applicable to analyze the temporal dynamics of the N cycle gene

Sensitivity study on nitrogen Brayton cycle coupled with a small ultra-long cycle fast reactor

International Nuclear Information System (INIS)

Seo, Seok Bin; Seo, Han; Bang, In Cheol

2014-01-01

The main characteristics of UCFR are constant neutron flux and power density. They move their positions every moment at constant speed along with axial position of fuel rod for 60 years. Simultaneously with the development of the reactors, a new power conversion system has been considered. To solve existing issues of vigorous sodium-water reaction in SFR with steam power cycle, many researchers suggested a closed Brayton cycle as an alternative technique for SFR power conversion system. Many inactive gases are selected as a working fluid in Brayton power cycle, mainly supercritical CO 2 (S-CO 2 ). However, S-CO 2 still has potential for reaction with sodium. CO 2 -sodium reaction produces solid product, which has possibility to have an auto ignition reaction around 600 .deg. C. Thus, instead of S-CO 2 , CEA in France has developed nitrogen power cycle for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). In addition to inactive characteristic of nitrogen with sodium, its thermal and physical similarity with air enables to easily adopt to existing air Brayton cycle technology. In this study, for an optimized power conversion system for UCFR, a nitrogen Brayton cycle was analyzed in thermodynamic aspect. Based on subchannel analysis data of UCFR-100, a parametric study for thermal performance of nitrogen Brayton cycle was achieved. The system maximum pressure significantly affects to the overall efficiency of cycle, while other parameters show little effects. Little differences of the overall efficiencies for all cases between three stages (BOC, MOC, EOC) indicate that the power cycle of UCFR-100 maintains its performance during the operation

Multiparameter Cell Cycle Analysis.

Science.gov (United States)

Jacobberger, James W; Sramkoski, R Michael; Stefan, Tammy; Woost, Philip G

2018-01-01

Cell cycle cytometry and analysis are essential tools for studying cells of model organisms and natural populations (e.g., bone marrow). Methods have not changed much for many years. The simplest and most common protocol is DNA content analysis, which is extensively published and reviewed. The next most common protocol, 5-bromo-2-deoxyuridine S phase labeling detected by specific antibodies, is also well published and reviewed. More recently, S phase labeling using 5'-ethynyl-2'-deoxyuridine incorporation and a chemical reaction to label substituted DNA has been established as a basic, reliable protocol. Multiple antibody labeling to detect epitopes on cell cycle regulated proteins, which is what this chapter is about, is the most complex of these cytometric cell cycle assays, requiring knowledge of the chemistry of fixation, the biochemistry of antibody-antigen reactions, and spectral compensation. However, because this knowledge is relatively well presented methodologically in many papers and reviews, this chapter will present a minimal Methods section for one mammalian cell type and an extended Notes section, focusing on aspects that are problematic or not well described in the literature. Most of the presented work involves how to segment the data to produce a complete, progressive, and compartmentalized cell cycle analysis from early G1 to late mitosis (telophase). A more recent development, using fluorescent proteins fused with proteins or peptides that are degraded by ubiquitination during specific periods of the cell cycle, termed "Fucci" (fluorescent, ubiquitination-based cell cycle indicators) provide an analysis similar in concept to multiple antibody labeling, except in this case cells can be analyzed while living and transgenic organisms can be created to perform cell cycle analysis ex or in vivo (Sakaue-Sawano et al., Cell 132:487-498, 2007). This technology will not be discussed.

Evaluation method for regional water cycle health based on nature-society water cycle theory

Science.gov (United States)

Zhang, Shanghong; Fan, Weiwei; Yi, Yujun; Zhao, Yong; Liu, Jiahong

2017-08-01

Regional water cycles increasingly reflect the dual influences of natural and social processes, and are affected by global climate change and expanding human activities. Understanding how to maintain a healthy state of the water cycle has become an important proposition for sustainable development of human society. In this paper, natural-social attributes of the water cycle are synthesized and 19 evaluation indices are selected from four dimensions, i.e., water-based ecosystem integrity, water quality, water resource abundance and water resource use. A hierarchical water-cycle health evaluation system is established. An analytic hierarchy process is used to set the weight of the criteria layer and index layer, and the health threshold for each index is defined. Finally, a water-cycle health composite-index assessment model and fuzzy recognition model are constructed based on the comprehensive index method and fuzzy mathematics theory. The model is used to evaluate the state of health of the water cycle in Beijing during 2010-2014 and in the planning year (late 2014), considering the transfer of 1 billion m3 of water by the South-to-North Water Diversion Project (SNWDP). The results show health scores for Beijing of 2.87, 3.10, 3.38, 3.11 and 3.02 during 2010-2014. The results of fuzzy recognition show that the sub-healthy grade accounted for 54%, 49%, 61% and 49% of the total score, and all years had a sub-healthy state. Results of the criteria layer analysis show that water ecosystem function, water quality and water use were all at the sub-healthy level and that water abundance was at the lowest, or sick, level. With the water transfer from the SNWDP, the health score of the water cycle in Beijing reached 4.04. The healthy grade accounted for 60% of the total score, and the water cycle system was generally in a healthy state. Beijing's water cycle health level is expected to further improve with increasing water diversion from the SNWDP and industrial

Density-Functional formalism

International Nuclear Information System (INIS)

Szasz, L.; Berrios-Pagan, I.; McGinn, G.

1975-01-01

A new Density-Functional formula is constructed for atoms. The kinetic energy of the electron is divided into two parts: the kinetic self-energy and the orthogonalization energy. Calculations were made for the total energies of neutral atoms, positive ions and for the He isoelectronic series. For neutral atoms the results match the Hartree-Fock energies within 1% for atoms with N 36 the results generally match the HF energies within 0.1%. For positive ions the results are fair; for the molecular applications a simplified model is developed in which the kinetic energy consists of the Weizsaecker term plus the Fermi energy reduced by a continuous function. (orig.) [de

Single top quark production at LEP200?

International Nuclear Information System (INIS)

Boos, E.; Ishikawa, T.; Kaneko, T.; Kawabata, S.; Kurihara, Y.; Shimizu, Y.; Tanaka, H.

1994-01-01

A complete tree-level calculation of the reaction e + e - → e + ν e anti tb (e - anti ν e t anti b) in the electroweak standard theory in the LEP200 energy range is presented. For top quark masses in the range 130 to 190 GeV the cross sections are found to be in the order of 10 -5 to 10 -6 pb. Therefore, the number of single top quark events is expected to be negligible even with an integrated luminosity of L = 500 pb -1 . It is further demonstrated that the Weizsaecker-Williams approximation is approaching the accurate cross section calculations resonably well. (orig.)

Parametric Investigation and Thermoeconomic Optimization of a Combined Cycle for Recovering the Waste Heat from Nuclear Closed Brayton Cycle

Directory of Open Access Journals (Sweden)

Lihuang Luo

2016-01-01

Full Text Available A combined cycle that combines AWM cycle with a nuclear closed Brayton cycle is proposed to recover the waste heat rejected from the precooler of a nuclear closed Brayton cycle in this paper. The detailed thermodynamic and economic analyses are carried out for the combined cycle. The effects of several important parameters, such as the absorber pressure, the turbine inlet pressure, the turbine inlet temperature, the ammonia mass fraction, and the ambient temperature, are investigated. The combined cycle performance is also optimized based on a multiobjective function. Compared with the closed Brayton cycle, the optimized power output and overall efficiency of the combined cycle are higher by 2.41% and 2.43%, respectively. The optimized LEC of the combined cycle is 0.73% lower than that of the closed Brayton cycle.

Political Budget Cycles

DEFF Research Database (Denmark)

Aaskoven, Lasse; Lassen, David Dreyer

2017-01-01

The political budget cycle—how elections affect government fiscal policy—is one of the most studied subjects in political economy and political science. The key theoretical question is whether incumbent governments can time or structure public finances in ways that improve their chances of reelec......The political budget cycle—how elections affect government fiscal policy—is one of the most studied subjects in political economy and political science. The key theoretical question is whether incumbent governments can time or structure public finances in ways that improve their chances...... on political budget cycles have recently focused on conditions under which such cycles are likely to obtain. Much recent research focuses on subnational settings, allowing comparisons of governments in similar institutional environments, and a consensus on the presences of cycles in public finances...

Fuel cycle economics of HTRs

Energy Technology Data Exchange (ETDEWEB)

Hansen, U.

1975-06-15

The High Temperature Reactor commands a unique fuel cycle flexibility and alternative options are open to the utilities. The reference thorium reactor operating in the U-233 recycle mode is 10 to 20% cheaper than the low-enriched reactor; however, the thorium cycle depends on the supply of 93% enriched uranium and the availability of reprocessing and refabrication facilities to utilize its bred fissile material. The economic landscape towards the end of the 20th Century will presumably be dominated by pronounced increases in the costs of natural resources. In the case of nuclear energy, resource considerations are reflected in the price of uranium, which is expected Lo have reached 50 $/lbm U3O8 in the early 1990s and around 100 $/lbm U3O8 around 2010. In this economic environment the fuel cycle advantage of the thorium system amounts to some 20% and is capable of absorbing substantial expenses in bringing about the closing of the out-of-pile cycle. A most attractive aspect of the HTR fuel cycle flexibility is for the utility to start operating the reactor on the low enriched uranium cycle and at a later date switch over to the thorium cycle as this becomes economically more and more attractive. The incentive amounts to some 50 M$ in terms of present worth money at the time of decision making, assumed to take place 10 years after start-up. The closing of the thorium cycle is of paramount importance and a step to realize this objective lies in simplifying the head-end reprocessing technology by abandoning the segregation concept of feed and breed coated particles in the reference cycle. A one-coated-particle scheme in which all discharged uranium isotopes are recycled in mixed oxide particles is feasible and suffers a very minor economic penalty only.

Cycle bases to the rescue

Science.gov (United States)

Tóbiás, Roland; Furtenbacher, Tibor; Császár, Attila G.

2017-12-01

Cycle bases of graph theory are introduced for the analysis of transition data deposited in line-by-line rovibronic spectroscopic databases. The principal advantage of using cycle bases is that outlier transitions -almost always present in spectroscopic databases built from experimental data originating from many different sources- can be detected and identified straightforwardly and automatically. The data available for six water isotopologues, H216O, H217O, H218O, HD16O, HD17O, and HD18O, in the HITRAN2012 and GEISA2015 databases are used to demonstrate the utility of cycle-basis-based outlier-detection approaches. The spectroscopic databases appear to be sufficiently complete so that the great majority of the entries of the minimum cycle basis have the minimum possible length of four. More than 2000 transition conflicts have been identified for the isotopologue H216O in the HITRAN2012 database, the seven common conflict types are discussed. It is recommended to employ cycle bases, and especially a minimum cycle basis, for the analysis of transitions deposited in high-resolution spectroscopic databases.

Optimization of the fuel cycle

International Nuclear Information System (INIS)

Kidd, S.W.; Balu, K.; Boczar, P.G.; Krebs, W.D.

1999-01-01

The nuclear fuel cycle can be optimized subject to a wide range of criteria. Prime amongst these are economics, sustainability of resources, environmental aspects, and proliferation-resistance of the fuel cycle. Other specific national objectives will also be important. These criteria, and their relative importance, will vary from country to country, and with time. There is no single fuel cycle strategy that is optimal for all countries. Within the short term, the industry is attached to dominant thermal reactor technologies, which themselves have two main variants, a cycle closed by reprocessing of spent fuel and subsequent recycling and a once through one where spent fuel is stored in advance of geological disposal. However, even with current technologies, much can be done to optimize the fuel cycles to meet the relevant criteria. In the long term, resource sustainability can be assured for centuries through the use of fast breeder reactors, supporting high-conversion thermal reactors, possibly also utilizing the thorium cycle. These must, however, meet the other key criteria by being both economic and safe. (author)

Gender differences in recreational and transport cycling: a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints

Directory of Open Access Journals (Sweden)

Heesch Kristiann C

2012-09-01

Full Text Available Abstract Background Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and in motivators and constraints to cycling, separately for recreational and transport cycling. Methods Adult members of a Queensland, Australia, community bicycling organization completed an online survey about their cycling patterns; cycling purposes; and personal, social and perceived environmental motivators and constraints (47% response rate. Closed and open-end questions were completed. Using the quantitative data, multivariable linear, logistic and ordinal regression models were used to examine associations between gender and cycling patterns, motivators and constraints. The qualitative data were thematically analyzed to expand upon the quantitative findings. Results In this sample of 1862 bicyclists, men were more likely than women to cycle for recreation and for transport, and they cycled for longer. Most transport cycling was for commuting, with men more likely than women to commute by bicycle. Men were more likely to cycle on-road, and women off-road. However, most men and women did not prefer to cycle on-road without designed bicycle lanes, and qualitative data indicated a strong preference by men and women for bicycle-only off-road paths. Both genders reported personal factors (health and enjoyment related as motivators for cycling, although women were more likely to agree that other personal, social and environmental factors were also motivating. The main constraints for both genders and both cycling purposes were perceived environmental factors

Sometimes "Newton's Method" Always "Cycles"

Science.gov (United States)

Latulippe, Joe; Switkes, Jennifer

2012-01-01

Are there functions for which Newton's method cycles for all non-trivial initial guesses? We construct and solve a differential equation whose solution is a real-valued function that two-cycles under Newton iteration. Higher-order cycles of Newton's method iterates are explored in the complex plane using complex powers of "x." We find a class of…

Accounting for the biogeochemical cycle of nitrogen in input-output life cycle assessment.

Science.gov (United States)

Singh, Shweta; Bakshi, Bhavik R

2013-08-20

Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen cycle. This paper incorporates the biogeochemical cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen cycle. This paper emphasizes the need for methods to manage the N cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online.

Fuel cycle modelling of open cycle thorium-fuelled nuclear energy systems

International Nuclear Information System (INIS)

Ashley, S.F.; Lindley, B.A.; Parks, G.T.; Nuttall, W.J.; Gregg, R.; Hesketh, K.W.; Kannan, U.; Krishnani, P.D.; Singh, B.; Thakur, A.; Cowper, M.; Talamo, A.

2014-01-01

Highlights: • We study three open cycle Th–U-fuelled nuclear energy systems. • Comparison of these systems is made to a reference U-fuelled EPR. • Fuel cycle modelling is performed with UK NNL code “ORION”. • U-fuelled system is economically favourable and needs least separative work per kWh. • Th–U-fuelled systems offer negligible waste and proliferation resistance advantages. - Abstract: In this study, we have sought to determine the advantages, disadvantages, and viability of open cycle thorium–uranium-fuelled (Th–U-fuelled) nuclear energy systems. This has been done by assessing three such systems, each of which requires uranium enriched to ∼20% 235 U, in comparison to a reference uranium-fuelled (U-fuelled) system over various performance indicators, spanning material flows, waste composition, economics, and proliferation resistance. The values of these indicators were determined using the UK National Nuclear Laboratory’s fuel cycle modelling code ORION. This code required the results of lattice-physics calculations to model the neutronics of each nuclear energy system, and these were obtained using various nuclear reactor physics codes and burn-up routines. In summary, all three Th–U-fuelled nuclear energy systems required more separative work capacity than the equivalent benchmark U-fuelled system, with larger levelised fuel cycle costs and larger levelised cost of electricity. Although a reduction of ∼6% in the required uranium ore per kWh was seen for one of the Th–U-fuelled systems compared to the reference U-fuelled system, the other two Th–U-fuelled systems required more uranium ore per kWh than the reference. Negligible advantages and disadvantages were observed for the amount and the properties of the spent nuclear fuel (SNF) generated by the systems considered. Two of the Th–U-fuelled systems showed some benefit in terms of proliferation resistance of the SNF generated. Overall, it appears that there is little

The life cycle of centrioles.

Science.gov (United States)

Hatch, E; Stearns, T

2010-01-01

Centrioles organize the centrosome and nucleate the ciliary axoneme, and the centriole life cycle has many parallels to the chromosome cycle. The centriole cycle in animals begins at fertilization with the contribution of two centrioles by the male gamete. In the ensuing cell cycles, the duplication of centrioles is controlled temporally, spatially, and numerically. As a consequence of the duplication mechanism, the two centrioles in a typical interphase cell are of different ages and have different functions. Here, we discuss how new centrioles are assembled, what mechanisms limit centriole number, and the consequences of the inherent asymmetry of centriole duplication and segregation.

Pseudo-simple heteroclinic cycles in R4

Science.gov (United States)

Chossat, Pascal; Lohse, Alexander; Podvigina, Olga

2018-06-01

We study pseudo-simple heteroclinic cycles for a Γ-equivariant system in R4 with finite Γ ⊂ O(4) , and their nearby dynamics. In particular, in a first step towards a full classification - analogous to that which exists already for the class of simple cycles - we identify all finite subgroups of O(4) admitting pseudo-simple cycles. To this end we introduce a constructive method to build equivariant dynamical systems possessing a robust heteroclinic cycle. Extending a previous study we also investigate the existence of periodic orbits close to a pseudo-simple cycle, which depends on the symmetry groups of equilibria in the cycle. Moreover, we identify subgroups Γ ⊂ O(4) , Γ ⊄ SO(4) , admitting fragmentarily asymptotically stable pseudo-simple heteroclinic cycles. (It has been previously shown that for Γ ⊂ SO(4) pseudo-simple cycles generically are completely unstable.) Finally, we study a generalized heteroclinic cycle, which involves a pseudo-simple cycle as a subset.

Not all counterclockwise thermodynamic cycles are refrigerators

Science.gov (United States)

Dickerson, R. H.; Mottmann, J.

2016-06-01

Clockwise cycles on PV diagrams always represent heat engines. It is therefore tempting to assume that counterclockwise cycles always represent refrigerators. This common assumption is incorrect: most counterclockwise cycles cannot be refrigerators. This surprising result is explored here for quasi-static ideal gas cycles, and the necessary conditions for refrigeration cycles are clarified. Three logically self-consistent criteria can be used to determine if a counterclockwise cycle is a refrigerator. The most fundamental test compares the counterclockwise cycle with a correctly determined corresponding Carnot cycle. Other criteria we employ include a widely accepted description of the functional behavior of refrigerators, and a corollary to the second law that limits a refrigerator's coefficient of performance.

Extended fuel cycle length

International Nuclear Information System (INIS)

Bruyere, M.; Vallee, A.; Collette, C.

1986-09-01

Extended fuel cycle length and burnup are currently offered by Framatome and Fragema in order to satisfy the needs of the utilities in terms of fuel cycle cost and of overall systems cost optimization. We intend to point out the consequences of an increased fuel cycle length and burnup on reactor safety, in order to determine whether the bounding safety analyses presented in the Safety Analysis Report are applicable and to evaluate the effect on plant licensing. This paper presents the results of this examination. The first part indicates the consequences of increased fuel cycle length and burnup on the nuclear data used in the bounding accident analyses. In the second part of this paper, the required safety reanalyses are presented and the impact on the safety margins of different fuel management strategies is examined. In addition, systems modifications which can be required are indicated

Detonation Jet Engine. Part 1--Thermodynamic Cycle

Science.gov (United States)

Bulat, Pavel V.; Volkov, Konstantin N.

2016-01-01

We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

ITER fuel cycle

International Nuclear Information System (INIS)

Leger, D.; Dinner, P.; Yoshida, H.

1991-01-01

Resulting from the Conceptual Design Activities (1988-1990) by the parties involved in the International Thermonuclear Experimental Reactor (ITER) project, this document summarizes the design requirements and the Conceptual Design Descriptions for each of the principal subsystems and design options of the ITER Fuel Cycle conceptual design. The ITER Fuel Cycle system provides for the handling of all tritiated water and gas mixtures on ITER. The system is subdivided into subsystems for fuelling, primary (torus) vacuum pumping, fuel processing, blanket tritium recovery, and common processes (including isotopic separation, fuel management and storage, and processes for detritiation of solid, liquid, and gaseous wastes). After an introduction describing system function and conceptual design procedure, a summary of the design is presented including a discussion of scope and main parameters, and the fuel design options for fuelling, plasma chamber vacuum pumping, fuel cleanup, blanket tritium recovery, and auxiliary and common processes. Design requirements are defined and design descriptions are given for the various subsystems (fuelling, plasma vacuum pumping, fuel cleanup, blanket tritium recovery, and auxiliary/common processes). The document ends with sections on fuel cycle design integration, fuel cycle building layout, safety considerations, a summary of the research and development programme, costing, and conclusions. Refs, figs and tabs

Quantifying the Adaptive Cycle.

Directory of Open Access Journals (Sweden)

David G Angeler

Full Text Available The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011 data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

The effectiveness of community-based cycling promotion: findings from the Cycling Connecting Communities project in Sydney, Australia

Directory of Open Access Journals (Sweden)

Merom Dafna

2010-01-01

Full Text Available Abstract Background Encouraging cycling is an important way to increase physical activity in the community. The Cycling Connecting Communities (CCC Project is a community-based cycling promotion program that included a range of community engagement and social marketing activities, such as organised bike rides and events, cycling skills courses, the distribution of cycling maps of the area and coverage in the local press. The aim of the study was to assess the effectiveness of this program designed to encourage the use of newly completed off-road cycle paths through south west Sydney, Australia. Methods The evaluation used a quasi-experimental design that consisted of a pre- and post-intervention telephone survey (24 months apart of a cohort of residents (n = 909 in the intervention area (n = 520 (Fairfield and Liverpool and a socio-demographically similar comparison area (n = 389 (Bankstown. Both areas had similar bicycle infrastructure. Four bicycle counters were placed on the main bicycle paths in the intervention and comparison areas to monitor daily bicycle use before and after the intervention. Results The telephone survey results showed significantly greater awareness of the Cycling Connecting Communities project (13.5% vs 8.0%, p Conclusion Despite relatively modest resources, the Cycling Connecting Communities project achieved significant increases in bicycle path use, and increased cycling in some sub-groups. However, this community based intervention with limited funding had very limited reach into the community and did not increase population cycling levels.

The spatial dimension of cycle logistics

Directory of Open Access Journals (Sweden)

Luca Staricco

2016-08-01

Full Text Available Cycle logistics is emerging as a promising alternative in urban freight transport. Compared to fossil fuelled vans, the use of cycles for delivering goods within urban areas offers advantages in terms of environmental friendliness, economic efficiency, flexibility, and liveability of urban neighbourhood. At the same time, cycle logistics has to face limits in terms of weight and volume of goods that can be delivered, distances that can be covered, and spatial urban structures that can be served. This latter issue has till now received less attention in the scientific literature: it is generally recognized that cycle logistics performs at its best in inner urban areas, but no systematic study has been realized to identify specific spatial requisites for the effectiveness of cycle logistics. This paper provides a brief review of the main issues that emerge from the literature over cycle logistics, and contributes to stimulate the debate over the spatial dimension of cycle logistics: it presents a classification of cycle logistics schemes, on the basis of their integration with other urban logistic facilities and of the spatial structure of delivery operations. A three-level classification is proposed, depending on the type of goods consolidation: only distribution without consolidation, consolidation in a fixed urban consolidation centre, or consolidation in a mobile depot; for each level, operational examples and case studies are provided. This systematizing typology could support both public and private operators in decisions about the organization of cycle logistics facilities, such as the location of urban consolidation centres or the composition of cycle fleets.

Economic evaluation of fast reactor fuel cycling

International Nuclear Information System (INIS)

Hu Ping; Zhao Fuyu; Yan Zhou; Li Chong

2012-01-01

Economic calculation and analysis of two kinds of nuclear fuel cycle are conducted by check off method, based on the nuclear fuel cycling process and model for fast reactor power plant, and comparison is carried out for the economy of fast reactor fuel cycle and PWR once-through fuel cycle. Calculated based on the current price level, the economy of PWR one-through fuel cycle is better than that of the fast reactor fuel cycle. However, in the long term considering the rising of the natural uranium's price and the development of the post treatment technology for nuclear fuels, the cost of the fast reactor fuel cycle is expected to match or lower than that of the PWR once-through fuel cycle. (authors)

Analysis of possible fuel cycles

International Nuclear Information System (INIS)

Boehm, H.; Kessler, G.; Engelmann, P.; Maerkl, H.; Stoll, W.

1978-01-01

A brief survey is presented of the most important fuel cycles. A rough analysis of fuel cycles is attempted under the aspects of proliferation, status of technical feasibility, resource conservation and waste management and the most important criteria for such an analysis are discussed. Among the multitude of potential combinations of fuel cycles and types of reactors only a few have reached a level of technical feasibility which would make them eligible for commercial implementation within the next decade. However, if, for instance, the higher proliferation resistance of a specific fuel cycle is to be utilized to diminish the worldwide proliferation hazard, that cycle would first of all have to be introduced on an industrial scale as quickly as possible. The analysis shows that the reduction of the bazard of worldwide proliferation will continue to be the objective primarily of international agreements and measures taken in the political realm. (orig.) [de

Advanced Fuel Cycle Economic Sensitivity Analysis

Energy Technology Data Exchange (ETDEWEB)

David Shropshire; Kent Williams; J.D. Smith; Brent Boore

2006-12-01

A fuel cycle economic analysis was performed on four fuel cycles to provide a baseline for initial cost comparison using the Gen IV Economic Modeling Work Group G4 ECON spreadsheet model, Decision Programming Language software, the 2006 Advanced Fuel Cycle Cost Basis report, industry cost data, international papers, the nuclear power related cost study from MIT, Harvard, and the University of Chicago. The analysis developed and compared the fuel cycle cost component of the total cost of energy for a wide range of fuel cycles including: once through, thermal with fast recycle, continuous fast recycle, and thermal recycle.

Polity age and political budget cycles

DEFF Research Database (Denmark)

Aaskoven, Lasse

2018-01-01

Incumbent incentive for competence-signaling and lack of voter information are generally thought to be factors that increase the prevalence of political budget cycles. These mechanisms should be more prevalent in new political units. Since the creation of new political units is rarely exogenous......-experimental to study whether political budget cycles are larger in new political units. Contrary to theoretical predictions, political budget cycles seem to be of a smaller scale in the new municipalities, but only regarding budget cycles in budgetary overruns. The findings are of wider interest for discussions about...... the mechanisms behind context-conditional political budget cycles....

The thorium fuel cycle

International Nuclear Information System (INIS)

Merz, E.R.

1977-01-01

The utilization of the thorium fuel cycle has long since been considered attractive owing to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Rapidly increasing uranium prices, public reluctance for widespread Pu recycling and expected delays for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, problems associated with reprocessing and waste handling, particularly with re-fabrication by remote handling of 233 U, are certainly not appreciably more difficult than for Pu recycling. To divert from uranium as a nuclear energy source it seems worth while intensifying future efforts for closing the Th/ 233 U fuel cycle. HTGRs are particularly promising for economic application. However, further research and development activities should not concentrate on this reactor type alone. Light- and heavy-water-moderated reactors, and even future fast breeders, may just as well take advantage of a demonstrated thorium fuel cycle. (author)

Understanding Solar Cycle Variability

Energy Technology Data Exchange (ETDEWEB)

Cameron, R. H.; Schüssler, M., E-mail: cameron@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

2017-07-10

The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock–Leighton-type dynamo model confirm the validity of the normal-mode approach.

Out-of-core nuclear fuel cycle economic optimization for nonequilibrium cycles

International Nuclear Information System (INIS)

Comes, S.A.

1987-01-01

A methodology and associated computer code was developed to determine near-optimum out-of-core fuel management strategies. The code, named OCEON (Out-of-Core Economic OptimizationN), identified feed-region sizes and enrichments, and partially burned fuel-reload strategies for each cycle of a multi-cycle planning horizon, subject to cycle-energy requirements and constraints on feed enrichments, discharge burnups, and the moderator temperature coefficient. A zero-dimensional reactor physics model, enhanced by a linear reactivity model to provide batch power shares, performs the initial feed enrichment, burnup and constraint evaluations, while a two-dimensional, nodal code is used to refine the calculations for the final solutions. The economic calculations are performed rapidly using an annuity-factor-based model. Use of Monte Carlo integer programming to select the optimum solutions allows for the determination of a family of near-optimum solutions, from which engineering judgment may be used to select an appropriate strategy. Results from various nonequilibrium cycle energy requirement cases typically show a large number of low-cost solutions near the optimum. This confirms that the Monte Carlo integer programming approach of generating a family of solutions will be most useful for selecting optimum strategies when other considerations, such as incore loading pattern concerns, must be addressed

Parametric-based thermodynamic analysis of organic Rankine cycle as bottoming cycle for combined-cycle power plant

International Nuclear Information System (INIS)

Qureshi, S.; Memon, A.G.; Abbasi, A.F.

2017-01-01

In Pakistan, the thermal efficiency of the power plants is low because of a huge share of fuel energy is dumped into the atmosphere as waste heat. The ORC (Organic Rankine Cycle) has been revealed as one of the promising technologies to recover waste heat to enhance the thermal efficiency of the power plant. In current work, ORC is proposed as a second bottoming cycle for existing CCPP (Combined Cycle Power Plant). In order to assess the efficiency of the plant, a thermodynamic model is developed in the ESS (Engineering Equation Solver) software. The developed model is used for parametric analysis to assess the effects of various operating parameters on the system performance. The analysis of results shows that the integration of ORC system with existing CCPP system enhances the overall power output in the range of 150.5-154.58 MW with 0.24-5% enhancement in the efficiency depending on the operating conditions. During the parametric analysis of ORC, it is observed that inlet pressure of the turbine shows a significant effect on the performance of the system as compared to other operating parameters. (author)

BUSINESS CYCLES, ELECTORAL CYCLES. TOWARD A THEORETICAL FRAME OF INTERACTION

Directory of Open Access Journals (Sweden)

BOGDAN-LUCIAN DOSPINESCU

2015-06-01

Full Text Available The idea of cyclical movement of a system: be it political, economic, institutional, is one of the constants of critical thinking. In this sense, there is a natural cyclic movement that cannot be avoided (only amplified or diminished and is connected with the nature of these systems. The economy follows a cyclical movement; a period of growth follows a period of decline, and so on. So does popularity for political parties or leaders. In this paper, I explore the links between the business cycles and electoral cycles. For this purpose, I introduce the concept of electoral perception cycles. My hypothesis is that popularity of political parties and leaders follow a cyclical evolution, both on short and long term. I show how perception cycles can impact the “political business cycle theory”. There is great interest in political science literature for the factors that influence the fluctuations in Presidents’ popularity, especially from United States. However, very little has been said about Romania’s case. I investigate the hypothesis of electoral perception cycles looking at the popularity of former president Traian Basescu, over his two terms. The variable used to measure popularity is favorability, measured in national surveys, done face to face, on representative samplez, of around 1000 subjects. I’ve correlated the fluctuations in favorability over time, with key public events or political decisions taken by Traian Băsescu. The main findings are as follows. Firstly, there are significant short term fluctuations (short term perception cycles and they are correlated with major events on the agenda. I would point the following key moments: 1. The referendum for dismissal of the President in May 2007 – Traian Băsescu’s favorability increased by 7 percentage points; 2. The referendum for unicameral Parliament with 300 MPs in the fall of 2009. Coupled with victory in the presidential election, it lead to an increase of 10 percentage

Gender differences in recreational and transport cycling: a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints

OpenAIRE

Heesch, Kristiann C; Sahlqvist, Shannon; Garrard, Jan

2012-01-01

Abstract Background Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and i...

IFR fuel cycle demonstration in the EBR-II Fuel Cycle Facility

International Nuclear Information System (INIS)

Lineberry, M.J.; Phipps, R.D.; Rigg, R.H.; Benedict, R.W.; Carnes, M.D.; Herceg, J.E.; Holtz, R.E.

1991-01-01

The next major milestone of the IFR (Integral Fast Reactor) program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase which includes completion of facility modifications, and installation and cold checkout of process equipment. This paper reviews the design and construction of the facility, the design and fabrication of the process equipment, and the schedule and initial plan for its operation. (author)

IFR fuel cycle demonstration in the EBR-II Fuel Cycle Facility

International Nuclear Information System (INIS)

Lineberry, M.J.; Phipps, R.D.; Rigg, R.H.; Benedict, R.W.; Carnes, M.D.; Herceg, J.E.; Holtz, R.E.

1991-01-01

The next major milestone of the IFR program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase which includes completion of facility modifications, and installation and cold checkout of process equipment. This paper reviews the design and construction of the facility, the design and fabrication of the process equipment, and the schedule and initial plan for its operation. 5 refs., 4 figs

IFR fuel cycle

International Nuclear Information System (INIS)

Battles, J.E.; Miller, W.E.; Lineberry, M.J.; Phipps, R.D.

1992-01-01

The next major milestone of the IFR program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase, which includes completion of facility modifications and installation and cold checkout of process equipment. This paper reviews the development of the electrorefining pyroprocess, the design and construction of the facility for the hot demonstration, the design and fabrication of the equipment, and the schedule and initial plan for its operation

Life Cycle Impact Assessment

DEFF Research Database (Denmark)

Rosenbaum, Ralph K.; Hauschild, Michael Zwicky; Boulay, Anne-Marie

2018-01-01

This chapter is dedicated to the third phase of an LCA study, the Life Cycle Impact Assessment (LCIA) where the life cycle inventory’s information on elementary flows is translated into environmental impact scores. In contrast to the three other LCA phases, LCIA is in practice largely automated...

Management Cycle: from Planning to Evaluation

OpenAIRE

Kova?i?, Luka; Jakši?, Želimir

2008-01-01

The planning process in health care known as management cycle or cycle of organization and management is described. The cycle is divided in four main elements: planning, organization, implementation and evaluation. Each element is defined and described.

Cycling environmental perception in Beijing – A study of residents' attitudes towards future cycling and car purchasing

DEFF Research Database (Denmark)

Zhao, Chunli; Nielsen, Thomas Alexander Sick; Olafsson, Anton Stahl

2018-01-01

distances up to 2 km are positively linked to future cycling prospects. Non-car owners' attitude to future car ownership is strongly linked to socio-demographic status - low education and low income level groups seems to be most unlikely to take up driving in the future. To encourage people to cycle more...... and drive less, policy should direct efforts to promoting the clarity of cycling space on the street and strengthen pro-cycling policies. Attention should also be given to stabilizing the current travel modes of non-car users, including promoting the image of cycling, improving the service of walking...

The thorium fuel cycle

International Nuclear Information System (INIS)

Merz, E.R.

1977-01-01

The utilization of the thorium fuel cycle has long since been considered attractive due to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Although the uranium ore as well as the separative work requirements are usually lower for any thorium-based fuel cycle in comparison to present uranium-plutonium fuel cycles of thermal water reactors, interest by nuclear industry has hitherto been marginal. Fast increasing uranium prices, public reluctance against widespread Pu-recycling and expected retardations for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, it could be learned in the meantime that problems associated with reprocessing and waste handling, but particularly with a remote refabrication of 233 U are certainly not appreciably more difficult than for Pu-recycling. This may not only be due to psychological constraints but be based upon technological as well as economical facts, which have been mostly neglected up till now. In order to diversify from uranium as a nuclear energy source it seems to be worthwhile to greatly intensify efforts in the future for closing the Th/ 233 U fuel cycle. HTGR's are particularly promising for economic application. However, further R and D activites should not be solely focussed on this reactor type alone. Light and heavy-water moderated reactors, as well as even fast breeders later on, may just as well take advantage of a demonstrated thorium fuel cycle. A summary is presented of the state-of-the-art of Th/ 233 U-recycling technology and the efforts still necessary to demonstrate this technology all the way through to its industrial application

Advanced fuel cycles in CANDU reactors

International Nuclear Information System (INIS)

Green, R.E.; Boczar, P.G.

1990-04-01

This paper re-examines the rationale for advanced nuclear fuel cycles in general, and for CANDU advanced fuel cycles in particular. The traditional resource-related arguments for more uranium nuclear fuel cycles are currently clouded by record-low prices for uranium. However, the total known conventional uranium resources can support projected uranium requirements for only another 50 years or so, less if a major revival of the nuclear option occurs as part of the solution to the world's environmental problems. While the extent of the uranium resource in the earth's crust and oceans is very large, uncertainty in the availability and price of uranium is the prime resource-related motivation for advanced fuel cycles. There are other important reasons for pursuing advanced fuel cycles. The three R's of the environmental movement, reduce, recycle, reuse, can be achieved in nuclear energy production through the employment of advanced fuel cycles. The adoption of more uranium-conserving fuel cycles would reduce the amount of uranium which needs to be mined, and the environmental impact of that mining. Environmental concerns over the back end of the fuel cycle can be mitigated as well. Higher fuel burnup reduces the volume of spent fuels which needs to be disposed of. The transmutation of actinides and long-lived fission products into short-lived fission products would reduce the radiological hazard of the waste from thousands to hundreds of years. Recycling of uranium and/or plutonium in spent fuel reuses valuable fissile material, leaving only true waste to be disposed of. Advanced fuel cycles have an economical benefit as well, enabling a ceiling to be put on fuel cycle costs, which are

Life-cycle assessment of semiconductors

CERN Document Server

Boyd, Sarah B

2012-01-01

Life-Cycle Assessment of Semiconductors presents the first and thus far only available transparent and complete life cycle assessment of semiconductor devices. A lack of reliable semiconductor LCA data has been a major challenge to evaluation of the potential environmental benefits of information technologies (IT). The analysis and results presented in this book will allow a higher degree of confidence and certainty in decisions concerning the use of IT in efforts to reduce climate change and other environmental effects. Coverage includes but is not limited to semiconductor manufacturing trends by product type and geography, unique coverage of life-cycle assessment, with a focus on uncertainty and sensitivity analysis of energy and global warming missions for CMOS logic devices, life cycle assessment of flash memory and life cycle assessment of DRAM. The information and conclusions discussed here will be highly relevant and useful to individuals and institutions. The book also: Provides a detailed, complete a...

Comparative analysis of thermodynamic performance and optimization of organic flash cycle (OFC) and organic Rankine cycle (ORC)

International Nuclear Information System (INIS)

Lee, Ho Yong; Park, Sang Hee; Kim, Kyoung Hoon

2016-01-01

A comparative thermodynamic performance and optimization analysis of basic organic flash cycle (OFCB), organic flash cycle with two-phase expander (OFCT), and organic Rankine cycle (ORC) activated by low-temperature sensible energy is carried out in the subcritical pressure regions. The three substances of R245fa, R123, and o-xylene are considered as the working fluids. Effects of cycle type, working fluid, and evaporation and source temperatures are systemically investigated on the system performance such as net power production, thermal and exergy efficiencies, and exergy destruction ratios at each component of the systems. Results show that the cycle type or working fluid which shows optimum performance depends on the source temperature, and organic flash cycle shows a potential for efficient recovery of low grade energy source.

Practical introduction of thorium fuel cycles

International Nuclear Information System (INIS)

Kasten, P.R.

1982-01-01

The pracitcal introduction of throrium fuel cycles implies that thorium fuel cycles compete economically with uranium fuel cycles in economic nuclear power plants. In this study the reactor types under consideration are light water reactors (LWRs), heavy water reactors (HWRs), high-temperature gas-cooled reactors (HTGRs), and fast breeder reactors (FBRs). On the basis that once-through fuel cycles will be used almost exclusively for the next 20 or 25 years, introduction of economic thorium fuel cycles appears best accomplished by commercial introduction of HTGRs. As the price of natural uranium increases, along with commercialization of fuel recycle, there will be increasing incentive to utilize thorium fuel cycles in heavy water reactors and light water reactors as well as in HTGRs. After FBRs and fuel recycle are commercialized, use of thorium fuel cycles in the blanket of FBRs appears advantageous when fast breeder reactors and thermal reactors operate in a symbiosis mode (i.e., where 233 U bred in the blanket of a fast breeder reactor is utilized as fissile fuel in thermal converter reactors)

Exact solution of the XXX Gaudin model with generic open boundaries

Science.gov (United States)

Hao, Kun; Cao, Junpeng; Yang, Tao; Yang, Wen-Li

2015-03-01

The XXX Gaudin model with generic integrable open boundaries specified by the most general non-diagonal reflecting matrices is studied. Besides the inhomogeneous parameters, the associated Gaudin operators have six free parameters which break the U(1) -symmetry. With the help of the off-diagonal Bethe ansatz, we successfully obtained the eigenvalues of these Gaudin operators and the corresponding Bethe ansatz equations.

Slavnov and Gaudin-Korepin formulas for models without U (1) symmetry: the XXX chain on the segment

Science.gov (United States)

Belliard, S.; Pimenta, R. A.

2016-04-01

We consider the isotropic spin -\\frac{1}{2} Heisenberg chain with the most general integrable boundaries. The scalar product between the on-shell Bethe vector and its off-shell dual, obtained by means of the modified algebraic Bethe ansatz, is given by a modified Slavnov formula. The corresponding Gaudin-Korepin formula, i.e., the square of the norm, is also obtained.

Aed, mida pole kunagi kastetud / Kaja Kurg

Index Scriptorium Estoniae

Kurg, Kaja, 1959-

2008-01-01

Inglise aednikust Beth Chatto'st (sünd. 1923), tema Essexisse rajatud kruusaaiast, mille teevad lopsakaks ja värvikaks kasvupaika sobivad taimed. Lühidalt ülejäänud aiast: vee-, metsa-, alpi- ja taimeaiast. Lk. 72: Beth Chatto kiri Christopher Lloydile (Dear Friend & Gardener : Letters of Life and Gardening, London : Frances Lincoln, 1998), mille on tõlkinud Jaan Mettik

Thermal cycling in multifilamentary superconducting composites

International Nuclear Information System (INIS)

Aragao, E.E.A. de.

1984-01-01

NbTi-Cu multifilamentary superconducting composites were embedded, polished, characterized by microscopic techniques, and analyzed in a qualitative and semiquantitative way by energy dispersion technique. The superconductors were submitted to thermal cycling between the ambient temperature and the boiling point of helium (4.2K), for different number of cycles. The aims were to study the correlation between the possible microstructural damages due to thermal stresses arising in the composite during cycling and the variation of properties of the material with the number of cycles as well as to verify the validity of an elastic model for thermal stresses for low temperature cycles. (author)

Understanding the petrochemical cycle: Part 1

International Nuclear Information System (INIS)

Sedriks, W.

1994-01-01

Fitness in the hydrocarbon processing industry (HPI) arena involves understanding and coping with business cycles: supply and demand. This becomes increasingly more important as the industry globalizes and matures. Competitive-edge thinking needs to look hard at the forces that influence business cycles. Recognition of potential pitfalls is very important when considering: future capacity expansion, mergers and acquisitions, market departure, plant closure, potential product substitution, etc. Understanding pricing mechanisms and the workings of hockey-stick profitability profiles help HPI operators endure cycle downturns and prepare plants to maximize profits for the next upswing. The paper discusses characteristic trends, cycles in the hydrocarbon processing industry, current conditions, and mitigating cycle effects

High-accuracy energy formulas for the attractive two-site Bose-Hubbard model

Science.gov (United States)

Ermakov, Igor; Byrnes, Tim; Bogoliubov, Nikolay

2018-02-01

The attractive two-site Bose-Hubbard model is studied within the framework of the analytical solution obtained by the application of the quantum inverse scattering method. The structure of the ground and excited states is analyzed in terms of solutions of Bethe equations, and an approximate solution for the Bethe roots is given. This yields approximate formulas for the ground-state energy and for the first excited-state energy. The obtained formulas work with remarkable precision for a wide range of parameters of the model, and are confirmed numerically. An expansion of the Bethe state vectors into a Fock space is also provided for evaluation of expectation values, although this does not have accuracy similar to that of the energies.

Exact ground-state correlation functions of an atomic-molecular Bose–Einstein condensate model

Science.gov (United States)

Links, Jon; Shen, Yibing

2018-05-01

We study the ground-state properties of an atomic-molecular Bose–Einstein condensate model through an exact Bethe Ansatz solution. For a certain range of parameter choices, we prove that the ground-state Bethe roots lie on the positive real-axis. We then use a continuum limit approach to obtain a singular integral equation characterising the distribution of these Bethe roots. Solving this equation leads to an analytic expression for the ground-state energy. The form of the expression is consistent with the existence of a line of quantum phase transitions, which has been identified in earlier studies. This line demarcates a molecular phase from a mixed phase. Certain correlation functions, which characterise these phases, are then obtained through the Hellmann–Feynman theorem.

Life cycle management (LCM)

DEFF Research Database (Denmark)

Remmen, Arne; Thrane, Mikkel

2004-01-01

The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels.......The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels....

The NEWS Water Cycle Climatology

Science.gov (United States)

Rodell, M.; Beaudoing, H. K.; L'Ecuyer, T.; Olson, W. S.

2012-12-01

NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

The NEWS Water Cycle Climatology

Science.gov (United States)

Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

2012-01-01

NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

Energy and exergy analysis of a closed Brayton cycle-based combined cycle for solar power tower plants

International Nuclear Information System (INIS)

Zare, V.; Hasanzadeh, M.

2016-01-01

Highlights: • A novel combined cycle is proposed for solar power tower plants. • The effects of solar subsystem and power cycle parameters are examined. • The proposed combined cycle yields exergy efficiencies of higher than 70%. • For the overall power plant exergy efficiencies of higher than 30% is achievable. - Abstract: Concentrating Solar Power (CSP) technology offers an interesting potential for future power generation and research on CSP systems of all types, particularly those with central receiver system (CRS) has been attracting a lot of attention recently. Today, these power plants cannot compete with the conventional power generation systems in terms of Levelized Cost of Electricity (LCOE) and if a competitive LCOE is to be reached, employing an efficient thermodynamic power cycle is deemed essential. In the present work, a novel combined cycle is proposed for power generation from solar power towers. The proposed system consists of a closed Brayton cycle, which uses helium as the working fluid, and two organic Rankine cycles which are employed to recover the waste heat of the Brayton cycle. The system is thermodynamically assessed from both the first and second law viewpoints. A parametric study is conducted to examine the effects of key operating parameters (including solar subsystem and power cycle parameters) on the overall power plant performance. The results indicate that exergy efficiencies of higher than 30% are achieved for the overall power plant. Also, according to the results, the power cycle proposed in this work has a better performance than the other investigated Rankine and supercritical CO_2 systems operating under similar conditions, for these types of solar power plants.

Automatic control of clock duty cycle

Science.gov (United States)

Feng, Xiaoxin (Inventor); Roper, Weston (Inventor); Seefeldt, James D. (Inventor)

2010-01-01

In general, this disclosure is directed to a duty cycle correction (DCC) circuit that adjusts a falling edge of a clock signal to achieve a desired duty cycle. In some examples, the DCC circuit may generate a pulse in response to a falling edge of an input clock signal, delay the pulse based on a control voltage, adjust the falling edge of the input clock signal based on the delayed pulse to produce an output clock signal, and adjust the control voltage based on the difference between a duty cycle of the output clock signal and a desired duty cycle. Since the DCC circuit adjusts the falling edge of the clock cycle to achieve a desired duty cycle, the DCC may be incorporated into existing PLL control loops that adjust the rising edge of a clock signal without interfering with the operation of such PLL control loops.

Multidimensional evaluation on FR cycle systems

International Nuclear Information System (INIS)

Nakai, Ryodai; Fujii, Sumio; Takakuma, Katsuyuki; Katoh, Atsushi; Ono, Kiyoshi; Ohtaki, Akira; Shiotani, Hiroki

2004-01-01

This report explains some results of the multidimensional evaluation on various fast reactor cycle system concepts from an interim report of the 2nd phase of ''Feasibility Study on Commercialized FR Cycle System''. This method is designed to give more objective and more quantitative evaluations to clarify commercialized system candidate concepts. Here we brief current evaluation method from the five viewpoints of safety, economy, environment, resource and non-proliferation, with some trial evaluation results for some cycles consist of promising technologies in reactor, core and fuel, reprocessing and fuel manufacture. Moreover, we describe FR cycle deployment scenarios which describe advantages and disadvantages of the cycles from the viewpoints of uranium resource and radioactive waste based on long-term nuclear material mass flow analyses and advantages of the deployment of FR cycle itself from the viewpoints of the comparison with alternative power supplies as well as cost and benefit. (author)

IAEA activities on nuclear fuel cycle 1997

Energy Technology Data Exchange (ETDEWEB)

Oi, N [International Atomic Energy Agency, Vienna (Austria). Nuclear Fuel Cycle and Materials Section

1997-12-01

The presentation discussing the IAEA activities on nuclear fuel cycle reviews the following issues: organizational charts of IAEA, division of nuclear power and the fuel cycle, nuclear fuel cycle and materials section; 1997 budget estimates; budget trends; the nuclear fuel cycle programme.

IAEA activities on nuclear fuel cycle 1997

International Nuclear Information System (INIS)

Oi, N.

1997-01-01

The presentation discussing the IAEA activities on nuclear fuel cycle reviews the following issues: organizational charts of IAEA, division of nuclear power and the fuel cycle, nuclear fuel cycle and materials section; 1997 budget estimates; budget trends; the nuclear fuel cycle programme

Fuel cycle related parametric study considering long lived actinide production, decay heat and fuel cycle performances

International Nuclear Information System (INIS)

Raepsaet, X.; Damian, F.; Lenain, R.; Lecomte, M.

2001-01-01

One of the very attractive HTGR reactor characteristics is its highly versatile and flexible core that can fulfil a wide range of diverse fuel cycles. Based on a GTMHR-600 MWth reactor, analyses of several fuel cycles were carried out without taking into account common fuel particle performance limits (burnup, fast fluence, temperature). These values are, however, indicated in each case. Fuel derived from uranium, thorium and a wide variety of plutonium grades has been considered. Long-lived actinide production and total residual decay heat were evaluated for the various types of fuel. The results presented in this papers provide a comparison of the potential and limits of each fuel cycle and allow to define specific cycles offering lowest actinide production and residual heat associated with a long life cycle. (author)

CO2 cycle

Science.gov (United States)

Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

2017-01-01

This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

International Business Cycle

Directory of Open Access Journals (Sweden)

Marek Lubiński

2007-04-01

Full Text Available Prime stylized facts of international business cycle theory refer to positive correlation in the cyclical components of important macroeconomic variables across countries. However a number of indicators of business cycle synchronization do not point to clear trends. It can be ascribed to the fact that different forces influence level of business cycle correlation. When investigating into the forces behind the commonness in aggregate fluctuations economic research seems to have pointed in two directions. One strand of the literature examines the idea of common exogenous shocks that affect economies simultaneously. In addition to that economic interdependencies such as trade in goods and services or capital account transactions may serve as the channels through which disturbances spill over across countries.The observed degree of output co movement reflects both the nature of the shocks that have occurred and the degree of economic interdependence. In the periods when common shocks prevail level of synchronization is usually higher than in times of transmission dominance.

Fast Cycled Superconducting Magnet - Connecting hydraulically the Fast Cycled magnet to the cryogenic feed box.

CERN Multimedia

Maximilien Brice

2012-01-01

Photo 1 : Connecting hydraulically the Fast Cycled magnet to the cryogenic feed box. Patrck Viret and Guy Deferne technicians of TE-MSC-TF in SM18. - Photo 2 : Installation of the Fast Cycled Superconducting Magnet (FCM) to the new cold feed box in Sm18. - Photo 3 : Connecting the powering cables of the FCM to the feed box. - Photo 5/6 : The connections of the Fast Cycled Magnet. Intermediate pieces. - Photo 7 : Hydraulic connections of the Fast Cycle Magnet cable to allow the cooling of the magnet’s conductor ( Cable in conduit type) with supercritical helium. - Photo 8 : Verification of the connection: design versus reality. Guy Deferne and Frederick Rougemont, technicians of TE-MSC-TE in SM18.

[Physiological differences between cycling and running].

Science.gov (United States)

Millet, Grégoire

2009-08-05

This review compares the differences in systemic responses (VO2max, anaerobic threshold, heart rate and economy) and in underlying mechanisms of adaptation (ventilatory and hemodynamic and neuromuscular responses) between cycling and running. VO2max is specific to the exercise modality. Overall, there is more physiological training transfer from running to cycling than vice-versa. Several other physiological differences between cycling and running are discussed: HR is different between the two activities both for maximal and sub-maximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than running due to mechanical constraints. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.

Metabolic Interaction between Urea Cycle and Citric Acid Cycle Shunt: A Guided Approach

Science.gov (United States)

Pesi, Rossana; Balestri, Francesco; Ipata, Piero L.

2018-01-01

This article is a guided pedagogical approach, devoted to postgraduate students specializing in biochemistry, aimed at presenting all single reactions and overall equations leading to the metabolic interaction between ureagenesis and citric acid cycle to be incorporated into a two-three lecture series about the interaction of urea cycle with other…

On Acyclicity of Games with Cycles

DEFF Research Database (Denmark)

Andersson, Daniel; Gurvich, Vladimir; Hansen, Thomas Dueholm

2009-01-01

We study restricted improvement cycles (ri-cycles) in finite positional n-person games with perfect information modeled by directed graphs (digraphs) that may contain cycles. We obtain criteria of restricted improvement acyclicity (ri-acyclicity) in two cases: for n = 2 and for acyclic digraphs. We...

New insight into regenerated air heat pump cycle

International Nuclear Information System (INIS)

Zhang, Chun-Lu; Yuan, Han; Cao, Xiang

2015-01-01

Regenerated air (reverse Brayton) cycle has unique potentials in heat pump applications compared to conventional vapor-compression cycles. To better understand the regenerated air heat pump cycle characteristics, a thermodynamic model with new equivalent parameters was developed in this paper. Equivalent temperature ratio and equivalent isentropic efficiency of expander were introduced to represent the effect of regenerator, which made the regenerated air cycle in the same mathematical expressions as the basic air cycle and created an easy way to prove some important features that regenerated air cycle inherits from the basic one. Moreover, we proved in theory that the regenerator does not always improve the air cycle efficiency. Larger temperature ratio and lower effectiveness of regenerator could make the regenerated air cycle even worse than the basic air cycle. Lastly, we found that only under certain conditions the cycle could get remarkable benefits from a well-sized regenerator. These results would enable further study of the regenerated air cycle from a different perspective. - Highlights: • A thermodynamic model for regenerated air heat pump cycle was developed. • Equivalent temperature ratio and equivalent expander efficiency were introduced. • We proved regenerated air cycle can make heating capacity in line with heating load. • We proved the regenerator does not always improve the air cycle efficiency.

Fuel cycle oriented approach

International Nuclear Information System (INIS)

Petit, A.

1987-01-01

The term fuel cycle oriented approach is currently used to designate two quite different things: the attempt to consider all or part of a national fuel cycle as one material balance area (MBA) or to consider individual MBAs existing in a state while designing a unique safeguards approach for each and applying the principle of nondiscrimination to fuel cycles as a whole, rather than to individual facilities. The merits of such an approach are acceptability by the industry and comparison with the contemplated establishment of long-term criteria. The following points concern the acceptability by the industry: (1) The main interest of the industry is to keep an open international market and therefore, to have effective and efficient safeguards. (2) The main concerns of the industry regarding international safeguards are economic burden, intrusiveness, and discrimination. Answers to these legitimate concerns, which retain the benefits of a fuel cycle oriented approach, are needed. More specifically, the problem of reimbursing the operator the costs that he has incurred for the safeguards must be considered

Empirical solar/stellar cycle simulations

Directory of Open Access Journals (Sweden)

Santos Ângela R. G.

2015-01-01

Full Text Available As a result of the magnetic cycle, the properties of the solar oscillations vary periodically. With the recent discovery of manifestations of activity cycles in the seismic data of other stars, the understanding of the different contributions to such variations becomes even more important. With this in mind, we built an empirical parameterised model able to reproduce the properties of the sunspot cycle. The resulting simulations can be used to estimate the magnetic-induced frequency shifts.

The nuclear fuel cycle

International Nuclear Information System (INIS)

Jones, P.M.S.

1987-01-01

This chapter explains the distinction between fissile and fertile materials, examines briefly the processes involved in fuel manufacture and management, describes the alternative nuclear fuel cycles and considers their advantages and disadvantages. Fuel management is usually divided into three stages; the front end stage of production and fabrication, the back end stage which deals with the fuel after it is removed from the reactor (including reprocessing and waste treatment) and the stage in between when the fuel is actually in the reactor. These stages are illustrated and explained in detail. The plutonium fuel cycle and thorium-uranium-233 fuel cycle are explained. The differences between fuels for thermal reactors and fast reactors are explained. (U.K.)

Dynamic Simulations of Advanced Fuel Cycles

International Nuclear Information System (INIS)

Piet, Steven J.; Dixon, Brent W.; Jacobson, Jacob J.; Matthern, Gretchen E.; Shropshire, David E.

2011-01-01

Years of performing dynamic simulations of advanced nuclear fuel cycle options provide insights into how they could work and how one might transition from the current once-through fuel cycle. This paper summarizes those insights from the context of the 2005 objectives and goals of the U.S. Advanced Fuel Cycle Initiative (AFCI). Our intent is not to compare options, assess options versus those objectives and goals, nor recommend changes to those objectives and goals. Rather, we organize what we have learned from dynamic simulations in the context of the AFCI objectives for waste management, proliferation resistance, uranium utilization, and economics. Thus, we do not merely describe 'lessons learned' from dynamic simulations but attempt to answer the 'so what' question by using this context. The analyses have been performed using the Verifiable Fuel Cycle Simulation of Nuclear Fuel Cycle Dynamics (VISION). We observe that the 2005 objectives and goals do not address many of the inherently dynamic discriminators among advanced fuel cycle options and transitions thereof.

The status of nuclear fuel cycle system analysis for the development of advanced nuclear fuel cycles

Energy Technology Data Exchange (ETDEWEB)

Ko, Won Il; Kim, Seong Ki; Lee, Hyo Jik; Chang, Hong Rae; Kwon, Eun Ha; Lee, Yoon Hee; Gao, Fanxing [KAERI, Daejeon (Korea, Republic of)

2011-11-15

The system analysis has been used with different system and objectives in various fields. In the nuclear field, the system can be applied from uranium mining to spent fuel reprocessing or disposal which is called the nuclear fuel cycle. The analysis of nuclear fuel cycle can be guideline for development of advanced fuel cycle through integrating and evaluating the technologies. For this purpose, objective approach is essential and modeling and simulation can be useful. In this report, several methods which can be applicable for development of advanced nuclear fuel cycle, such as TRL, simulation and trade analysis were explained with case study

Answering Key Fuel Cycle Questions

International Nuclear Information System (INIS)

Piet, S.J.; Dixon, B.W.; Bennett, R.G.; Smith, J.D.; Hill, R.N.

2004-01-01

Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties

Primary water chemistry optimization for extended fuel cycle operation. Results of the 'Duo experimentation' after three cycles

International Nuclear Information System (INIS)

Viricel, L.; Andrieu, C.; Segura, J.C.; Rocher, A.; Thomazet, J.; Clinard, M.H.; Dacquait, F.

2002-01-01

The primary coolant conditioning in French nuclear power plants is essentially based on the boron-lithium coordinated chemistry, with a target pH of 7.2 at 300 C and a maximum lithium concentration of 2.2 mg/kg. In 1996, EDF 1300 MWe units began operating 18-month fuel cycles, increasing boron concentrations at the beginning of the cycles. Since today the maximum lithium concentration in normal operation is 2.2 mg/kg, extended cycle operation results in a decrease in the pH at the beginning of the cycles, which may possibly lead to deposits in RCS, and particularly on the fuel cladding, and increased dose rates. It has to be noted that today, the fuel assemblies maximum burnup is set at 52 GWd/tU. One solution is to adjust the pH by increasing the lithium content at the beginning of the cycles, which is easy to implement and does not require any modification on the units. Hence, EDF is testing a ''modified'' chemistry regime in the > during 4 fuel cycles, with a maximum authorized lithium content of 3.5 mg/kg at the beginning of the cycles in the Cattenom 2 pilot unit. The Golfech 1 reference unit implements a standard boron-lithium coordination pH 300 7.2. The major goal of the experimentation is to assess the impact of elevated lithium concentrations at the beginning of the cycles on fuel cladding oxide behavior, mass transport and dose rates. This paper presents the results of the first three cycles of the Duo experimentation. (author)

Rapsodie: A closed fuel cycle

International Nuclear Information System (INIS)

Levallet, E.H.; Costa, L.; Mougniot, J.C.; Robin, J.

1977-01-01

The Fortissimo Version of the core of the RAPSODIE fast reactor produces 40 MWTh. Since its start up in May 1970 in the CEN-CADARACHE its availability has stayed around 85%. Some of the mixed oxyde fuel pins UO 2 - 30% PuO 2 have already reached 150.000 MWd/t. The reprocessing is done in the pilot plant located in the La Hague Center and the plutonium obtained has already been re-used in the reactor. The Rapsodie-Fortissimo cycle is therefore now a closed cycle. This cycle is quite representative of fast reactor cycle characteristics and thus provides a remarkable research and development tool for the study of fabrication, in-reactor performances, transport, storage and reprocessing. These studies concern in particular the evolution of fission products and heavy isotopes content in fuel which controls both reprocessing schemes and intensity of emitted radiations. A program for the analysis of irradiated fuel has been developed either using samples collected all along the cycle, or following the actual reprocessing subassemblies. A set of basic data and calculation models has been established with two objectives: to give a better interpretation of the experimental program on one hand, and to extrapolate these results to the fuel cycle of fast reactors in general on the other hand. The first results have been quite encouraging up to now [fr

Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

Science.gov (United States)

Moghimi, Mahdi; Khosravian, Mohammadreza

2018-06-01

In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

Science.gov (United States)

Moghimi, Mahdi; Khosravian, Mohammadreza

2018-01-01

In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

Policy paper no. 1 : Pedestrians and cycling

Energy Technology Data Exchange (ETDEWEB)

Zbogar, H. [City of Brampton, ON (Canada)

2004-06-01

The City of Brampton's Transportation and Transit Master Plan includes a workable plan to promote walking and cycling facilities in the area. This paper reviewed existing policies, programs and practices in the City of Brampton that pertain to cycling and walking. Walking and cycling issues and trends were also reviewed with reference to the principles that improve the pedestrian and cycling environment, such as safety, security, convenience, continuity, comfort, coherence and attractiveness. The recreation, health and fitness benefits of walking and cycling were also outlined along with transportation, environmental, and economic benefits. The official plan for the city was included with reference to walking and cycling sections in the city. It was noted that effective pathways should be customer driven and respond to the needs of residents. They should also accommodate all uses, including walking, jogging, cycling and in-line skating. Experience of other jurisdictions in Ontario in providing walking and cycling facilities were also reviewed. It was noted that walking and cycling are significant elements of an intermodal transportation system and have a strong bearing on a city's vision for urban street design. 11 refs., 2 tabs., 3 figs.

Exploring cycle crash characteristics in Malaysia

Directory of Open Access Journals (Sweden)

Hamzah A.

2017-01-01

Full Text Available This paper explains the cycle road crash trend, characteristics and injuries in Malaysia. It analyses the in-depth road crash investigation data collected by the Royal Malaysian Police which was made available to MIROS crash database. Fatality data was utilized due to its consistency. Cycle casualties reflected a continual downward pattern for year 2009 to 2014 in which the number of cycle crash involvement reduced by 49% and fatalities dropped by 42%. Among the prevalent factors of cycle fatalities are >60 age group, federal and state roads and straight road sections, rural and small towns, evening peak hours, and mainly involving cars and motorcycles. It is hoped that all these information would spark interests to improve cycle safety in Malaysia.

Fuel cycle centres

International Nuclear Information System (INIS)

Hagen, M.

1977-01-01

The concept of co-locating and integrating fuel cycle facilities at one site is discussed. This concept offers considerable advantages, especially in minimizing the amount of radioactive material to be transported on public roads. Safeguards and physical protection as relating to such an integrated system of facilities are analysed in detail, also industrial and commercial questions. An overall risk-benefit evaluation turns out to be in favour of fuel cycle centres. These centres seem to be specifically attractive with regard to the back end of the fuel cycle, including on-site disposal of radioactive wastes. The respective German approach is presented as an example. Special emphasis is given to the site selection procedures in this case. Time scale and cost for the implementation of this concept are important factors to be looked at. Since participation of governmental institutions in these centres seems to be indispensable their respective roles as compared to industry must be clearly defined. The idea of adjusting fuel cycle centres to regional rather than national use might be an attractive option, depending on the specific parameters in the region, though results of existing multinational ventures are inconclusive in this respect. Major difficulties might be expected e.g. because of different national safety regulations and standards as well as commercial conditions among partner countries. Public acceptance in the host country seems to be another stumbling block for the realization of this type of multinational facilities

Role of the seasonal cycle in coupling climate and carbon cycling in subanartic zone

CSIR Research Space (South Africa)

Monteiro, PMS

2010-08-01

Full Text Available There is increasing evidence in the Southern Ocean that mesoscales and seasonal scales play an important role in the coupling of ocean carbon cycling and climate. The seasonal cycle is one of the strongest modes of variability in different...

Gauge-invariant, nonperturbative approach to the infrared-finite bound-state problem in QCD

International Nuclear Information System (INIS)

Gogokhia, V.Sh.

1989-09-01

Gauge invariant, nonperturbative approach to the bound state problem within the infrared finite Bethe-Salpeter equation is presented. Condition of cancellation of the nonperturbative infrared divergences is derived. Solutions for the quark propagator and corresponding quark gluon vertex function are written down which can be directly applied to the Bethe-Salpeter equation, in particular to the 'generalized ladder' approximation of this equation. (author) 18 refs.; 3 figs

Measuring business cycles in The Netherlands, 1815-1913: a comparison of business cycle dating methods

OpenAIRE

Bonenkamp, Jan; Jacobs, Jan; Kuper, Gerard H.

2001-01-01

This paper compares different business cycle dating methods both on theoretical and practical grounds. Weighing the pros and cons of these methods, and based on a new data set for The Netherlands in the nineteenth century, we finally recommend two preferred methods for doing further business cycle research on the economy of the Netherlands. With respect to the methods for finding turning points in the level of economic activity, the classical cycle definition, we prefer the Bry-Boschan algori...

Introducing advanced nuclear fuel cycles in Canada

International Nuclear Information System (INIS)

Duret, M.F.

1978-05-01

The ability of several different advanced fuel cycles to provide energy for a range of energy growth scenarios has been examined for a few special situations of interest in Canada. Plutonium generated from the CANDU-PHW operating on natural uranium is used to initiate advanced fuel cycles in the year 2000. The four fuel cycles compared are: 1) natural uranium in the CANDU-PHW; 2) high burnup thorium cycle in the CANDU-PHW; 3) self-sufficient thorium cycle in the CANDU-PHW; 4) plutonium-uranium cycle in a fast breeder reactor. The general features of the results are quite clear. While any plutonium generated prior to the introduction of the advanced fuel cycle remains, system requirements for natural uranium for each of the advanced fuel cycles are the same and are governed by the rate at which plants operating on natural uranium can be retired. When the accumulated plutonium inventory has been entirely used, natural uranium is again required to provide inventory for the advanced fuel cycle reactors. The time interval during which no uranium is required varies only from about 25 to 40 years for both thorium cycles, depending primarily on the energy growth rate. The breeder does not require the entire plutonium inventory produced and so would call for less processing of fuel from the PHW reactors. (author)

40 CFR 94.105 - Duty cycles.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Duty cycles. 94.105 Section 94.105... EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Test Procedures § 94.105 Duty cycles. (a) Overview. For....8(e), engines shall be tested using the appropriate duty cycles described in this section. (b...

When Product Life Cycle Meets Customer Activity Cycle

DEFF Research Database (Denmark)

Tan, Adrian Ronald

2007-01-01

Manufacturing companies have traditionally focused their efforts on designing, developing and producing products to offer on the market. Today global competition and demands for greater company responsibility of products throughout their entire life cycle are driving manufacturing companies to sh...

Carbon cycle makeover

DEFF Research Database (Denmark)

Canfield, Donald Eugene; Kump, Lee R.

2013-01-01

remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen...... geochemical cycle. But Earth is an old planet, and oxygen levels have changed through time (2). On page 540 of this issue, Schrag et al. (3) challenge the most commonly used geochemical approach to assess long-term changes in the coupled oxygen and carbon cycles....

High performance integrated solar combined cycles with minimum modifications to the combined cycle power plant design

International Nuclear Information System (INIS)

Manente, Giovanni

2016-01-01

Highlights: • Off-design model of a 390 MW_e three pressure combined cycle developed and validated. • The off-design model is used to evaluate different hybridization schemes with solar. • Power boosting and fuel saving with different design modifications are considered. • Maximum solar share of total electricity is only 1% with the existing equipment. • The maximum incremental solar radiation-to-electrical efficiency approaches 29%. - Abstract: The integration of solar energy into natural gas combined cycles has been successfully demonstrated in several integrated solar combined cycles since the beginning of this decade in many countries. There are many motivations that drive investments on integrated solar combined cycles which are primarily the repowering of existing power plants, the compliance with more severe environmental laws on emissions and the mitigation of risks associated with large solar projects. Integrated solar combined cycles are usually developed as brownfield facilities by retrofitting existing natural gas combined cycles and keeping the existing equipment to minimize costs. In this work a detailed off-design model of a 390 MW_e three pressure level natural gas combined cycle is built to evaluate different integration schemes of solar energy which either keep the equipment of the combined cycle unchanged or include new equipment (steam turbine, heat recovery steam generator). Both power boosting and fuel saving operation strategies are analyzed in the search for the highest annual efficiency and solar share. Results show that the maximum incremental power output from solar at design solar irradiance is limited to 19 MW_e without modifications to the existing equipment. Higher values are attainable only including a larger steam turbine. High solar radiation-to-electrical efficiencies in the range 24–29% can be achieved in the integrated solar combined cycle depending on solar share and extension of tube banks in the heat recovery

Actinide production in different HTR-fuel cycle concepts

International Nuclear Information System (INIS)

Filges, D.; Hecker, R.; Mirza, N.; Rueckert, M.

1978-01-01

At the 'Institut fuer Reaktorentwicklung der Kernforschungsanlage Juelich' the production of α-activities in the following HTR-OTTO cycle concepts were studied: 1. standard HTR cycle (U-Th); 2. low enriched HTR cycle (U-Pu); 3. near breeder HTR cycle (U-Th); 4. combined system (conventional and near breeder HTR). The production of α-activity in HTR Uranium-Thorium fuel cycles has been investigated and compared with the standard LWR cycles. The production of α-activity in HTR Uranium-Thorium fuel cycles has been investigated and compared with the standard LWR cycles. The calculations were performed by the short depletion code KASCO and the well-known ORIGEN program

Dual Pressure versus Hybrid Recuperation in an Integrated Solid Oxide Fuel Cell Cycle – Steam Cycle

DEFF Research Database (Denmark)

Rokni, Masoud

2014-01-01

A SOFC (solid oxide fuel cell) cycle running on natural gas was integrated with a ST (steam turbine) cycle. The fuel is desulfurized and pre-reformed before entering the SOFC. A burner was used to combust the remaining fuel after the SOFC stacks. The off-gases from the burner were used to produce...... pressure configuration steam cycle combined with SOFC cycle (SOFC-ST) was new and has not been studied previously. In each of the configuration, a hybrid recuperator was used to recovery the remaining energy of the off-gases after the HRSG. Thus, four different plants system setups were compared to each...... other to reveal the most superior concept with respect to plant efficiency and power. It was found that in order to increase the plant efficiency considerably, it was enough to use a single pressure with a hybrid recuperator instead of a dual pressure Rankine cycle....

Cell cycle gene expression under clinorotation

Science.gov (United States)

Artemenko, Olga

2016-07-01

Cyclins and cyclin-dependent kinase (CDK) are main regulators of the cell cycle of eukaryotes. It's assumes a significant change of their level in cells under microgravity conditions and by other physical factors actions. The clinorotation use enables to determine the influence of gravity on simulated events in the cell during the cell cycle - exit from the state of quiet stage and promotion presynthetic phase (G1) and DNA synthesis phase (S) of the cell cycle. For the clinorotation effect study on cell proliferation activity is the necessary studies of molecular mechanisms of cell cycle regulation and development of plants under altered gravity condition. The activity of cyclin D, which is responsible for the events of the cell cycle in presynthetic phase can be controlled by the action of endogenous as well as exogenous factors, but clinorotation is one of the factors that influence on genes expression that regulate the cell cycle.These data can be used as a model for further research of cyclin - CDK complex for study of molecular mechanisms regulation of growth and proliferation. In this investigation we tried to summarize and analyze known literature and own data we obtained relatively the main regulators of the cell cycle in altered gravity condition.

Teaching the Rock Cycle with Ease.

Science.gov (United States)

Bereki, Debra

2000-01-01

Describes a hands-on lesson for teaching high school students the concept of the rock cycle using sedimentary, metamorphic, and igneous rocks. Students use a rock cycle diagram to identify pairs of rocks. From the rock cycle, students explain on paper how their first rock became the second rock and vice versa. (PVD)

Reversible and irreversible heat engine and refrigerator cycles

Science.gov (United States)

Leff, Harvey S.

2018-05-01

Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

10 CFR 436.19 - Life cycle costs.

Science.gov (United States)

2010-01-01

... operation and maintenance costs: (c) Replacement costs less salvage costs of replaced building systems; and... 10 Energy 3 2010-01-01 2010-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT... Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the...

Plant Characteristics of an Integrated Solid Oxide Fuel Cell Cycle and a Steam Cycle

DEFF Research Database (Denmark)

Rokni, Masoud

2010-01-01

Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. Natural gas (NG) was used as the fuel for the plant. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier...... recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization unit...

Nature's third cycle a story of sunspots

CERN Document Server

Choudhuri, Arnab Rai

2015-01-01

The cycle of day and night and the cycle of seasons are two familiar natural cycles around which many human activities are organized. But is there a third natural cycle of importance for us humans? On 13 March 1989, six million people in Canada went without electricity for many hours: a large explosion on the sun was discovered as the cause of this blackout. Such explosions occur above sunspots, dark features on the surface of the Sun that have been observed through telescopes since the time of Galileo. The number of sunspots has been found to wax and wane over a period of 11 years. Although this cycle was discovered less than two centuries ago, it is becoming increasingly important for us as human society becomes more dependent on technology. For nearly a century after its discovery, the cause of the sunspot cycle remained completely shrouded in mystery. The 1908 discovery of strong magnetic fields in sunspots made it clear that the 11-year cycle is the magnetic cycle of the sun. It is only during the last ...

Solar cycles and climate variations

International Nuclear Information System (INIS)

Chistyakov, V.F.

1990-01-01