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Sample records for clebsch-gordan coefficients

  1. New information and entropic inequalities for Clebsch-Gordan coefficients

    OpenAIRE

    Chernega, V. N.; Manko, O. V.; Manko, V. I.; Seilov, Z.

    2016-01-01

    The Clebsch-Gordan coefficients of the group SU(2) are shown to satisfy new inequalities. They are obtained using the properties of Shannon and Tsallis entropies. The inequalities associated with the Wigner 3-j symbols are obtained using the relation of Clebsch-Gordan coefficients with probability distributions interpreted either as distributions for composite systems or distributions for noncomposite systems. The new inequalities were found for Hahn polynomials and hypergeometric functions

  2. A simple method for calculating Clebsch-Gordan coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Klink, W H; Wickramasekara, S, E-mail: william-klink@uiowa.ed, E-mail: wickrama@grinnell.ed, E-mail: s-wickram@uiowa.ed [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

    2010-09-15

    This paper presents a simple method for calculating Clebsch-Gordan coefficients for the tensor product of two unitary irreducible representations (UIRs) of the rotation group. The method also works for multiplicity-free irreducible representations appearing in the tensor product of any number of UIRs of the rotation group. The generalization to representations with multiplicity is straightforward and briefly discussed.

  3. Tables of Clebsch-Gordan coefficients adapted to the cubical, tetragonal and digonal double groups

    International Nuclear Information System (INIS)

    Some basic considerations on the Clebsch-Gordan coefficients adapted to a chain of sub-groups of the universal covering SU2 of the proper rotation group SO3 are reviewed. Extensive tables of Clebsch-Gordan coefficients adapted to a chain isomorphic to SU2 contains O' contains D'4 contains D'2 are presented for consultation. These coefficients are useful in various fields of molecular spectroscopy, particularly in the ligand field theory. The tables listed here constitute an extensive tabulation of coupling coefficients of molecular interest

  4. Bogoliubov q-transformation and Clebsch-Gordan coefficients for a q-oscillator

    Science.gov (United States)

    Zhedanov, A. S.

    1992-05-01

    The q-analog of the Bogoliubov transformation is found, yielding the third q-Bose operator from the two independent ones. In contrast to the ordinary case, this transformation is non-linear. Considered as a co-multiplication for the q-oscillator algebra, this transformation generates the Clebsch-Gordan series with coefficients expressed via the Kravchuk q-polynomials.

  5. Construction of SO(5)⊃SO(3) spherical harmonics and Clebsch-Gordan coefficients

    Science.gov (United States)

    Caprio, M. A.; Rowe, D. J.; Welsh, T. A.

    2009-07-01

    The SO(5)⊃SO(3) spherical harmonics form a natural basis for expansion of nuclear collective model angular wave functions. They underlie the recently-proposed algebraic method for diagonalization of the nuclear collective model Hamiltonian in an SU(1,1)×SO(5) basis. We present a computer code for explicit construction of the SO(5)⊃SO(3) spherical harmonics and use them to compute the Clebsch-Gordan coefficients needed for collective model calculations in an SO(3)-coupled basis. With these Clebsch-Gordan coefficients it becomes possible to compute the matrix elements of collective model observables by purely algebraic methods. Program summaryProgram title: GammaHarmonic Catalogue identifier: AECY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 346 421 No. of bytes in distributed program, including test data, etc.: 16 037 234 Distribution format: tar.gz Programming language: Mathematica 6 Computer: Any which supports Mathematica Operating system: Any which supports Mathematica; tested under Microsoft Windows XP and Linux Classification: 4.2 Nature of problem: Explicit construction of SO(5) ⊃ SO(3) spherical harmonics on S. Evaluation of SO(3)-reduced matrix elements and SO(5) ⊃ SO(3) Clebsch-Gordan coefficients (isoscalar factors). Solution method: Construction of SO(5) ⊃ SO(3) spherical harmonics by orthonormalization, obtained from a generating set of functions, according to the method of Rowe, Turner, and Repka [1]. Matrix elements and Clebsch-Gordan coefficients follow by construction and integration of SO(3) scalar products. Running time: Depends strongly on the maximum SO(5) and SO(3) representation labels involved. A few minutes for the calculation in the Mathematica notebook. References

  6. Projection operator method and a analog of quantum theory field of angular momentum. Clebsch-Gordan coefficients and irreducible tensor operators

    International Nuclear Information System (INIS)

    Structure of the suq(2) quantum algebra and properties of its irreducible representations are considered. Projection operator is constructed as power series of suq(2)-algebra generators. The explicit analytical formula for the q-analogue of Clebsch-Gordan coefficients is derived using this projector. The symmetry properties of these coefficients are discussed. Algebraic tables of coefficients are given. Tensor operators are introduced and Wigner-Eckart theorem is proven

  7. Method of the projection operators and q-analog of the quantum angular momentum theory. 1. Clebsch-Gordan coefficients and irreducible tensor operators

    International Nuclear Information System (INIS)

    The structure of the quantum algebra suq(2) and the properties of its irreducible representation are considered. The projection operator is constructed as a power series from generators of the suq(2) algebra. The explicit analytical formula for q-analog of Clebsch-Gordan coefficients is derived using this projector. Their symmetry properties are discussed. The algebraic tables of these coefficients are given. The tensor operators are introduced and the Wigner-Eckart theorem is proved. 23 refs.; 4 figs

  8. Programs for generating Clebsch-Gordan coefficients of SU(3) in SU(2) and SO(3) bases

    Science.gov (United States)

    Bahri, C.; Rowe, D. J.; Draayer, J. P.

    2004-05-01

    Computer codes are developed to calculate Clebsch-Gordan coefficients of SU(3) in both SU(2)- and SO(3)-coupled bases. The efficiency of this code derives from the use of vector coherent state theory to evaluate the required coefficients directly without recursion relations. The approach extends to other compact semi-simple Lie groups. The codes are given in subroutine form so that users can incorporate the codes into other programs. Program summaryTitle of program: SU3CGVCS Catalogue identifier: ADTN Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTN Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: Persons requesting the program must sign the standard CPC non-profit use license Computers for which the program is designed and others on which it is operable: SGI Origin 2000, HP Apollo 9000, Sun, IBM SP, Pentium Operating systems under which the program has been tested: IRIX 6.5, HP UX 10.01, SunOS, AIX, Linux Programming language used: FORTRAN 77 Memory required to execute with typical data: On the HP system, it requires about 732 KBytes. Disk space used for output: 2100+2460 bytes No. of bits in a word: 32 bit integer and 64 bit floating point numbers. No. of processors used: 1 Has the code been vectorized: No No. of bytes in distributed program, including test data, etc.: 26 309 No. of lines in distributed program, including test data, etc.: 3969 Distribution format: tar gzip file Nature of physical problem: The group SU(3) and its Lie algebra su(3) have important applications, for example, in elementary particle physics, nuclear physics, and quantum optics [1-3]. The code presented is particularly relevant for the last two fields. Clebsch-Gordan (CG) coefficients are required whenever the symmetries of many-body systems are used for the evaluation of matrix elements of tensor operators. Moreover, the construction of CG coefficients for SU(3) serves as a nontrivial prototype for larger compact

  9. Cumulative “roof effect” in high-resolution in vivo 31P NMR spectra of human calf muscle and the Clebsch Gordan coefficients of ATP at 1.5 T

    Science.gov (United States)

    Schröder, Leif; Schmitz, Christian; Bachert, Peter

    2005-05-01

    NMR spectra of non-weakly coupled spin systems exhibit asymmetries in line intensities known as "roof effect" in 1D spectroscopy. Due to limited spectral resolution, this effect has not been paid much attention so far in in vivo spectroscopy. But when high-quality spectra are obtained, this effect should be taken into account to explain the quantum-mechanical fine structure of the system. Adenosine 5'-triphosphate (ATP) represents a 31P spin system with multiple line splittings which are caused by J-couplings of medium strength at 1.5 T. We analyzed the ATP roof effect in vivo, especially for the β-ATP multiplet. The intensities of its outer resonances deviate by ca. 12.5% from a symmetrical triplet. As this asymmetry reflects the transition from Paschen-Back to Zeeman effect with total spin that is largely broken up, the Clebsch-Gordan coefficients of the system can be indicated in analogy to the hyperfine structure of hydrogen. Taking the roof effect into account, the χ2 of fitting in vivo ATP resonances is reduced by ca. 9% ( p < 0.005).

  10. Clebsch-Gordan construction of lattice interpolating fields for excited baryons

    Energy Technology Data Exchange (ETDEWEB)

    S. Basak; R. Edwards; G. Fleming; U. Heller; C. Morningstar; D. Richards; I. Sato; S. Wallace

    2005-08-01

    Large sets of baryon interpolating field operators are developed for use in lattice QCD studies of baryons with zero momentum. Operators are classified according to the double-valued irreducible representations of the octahedral group. At first, three-quark smeared, local operators are constructed for each isospin and strangeness and they are classified according to their symmetry with respect to exchange of Dirac indices. Nonlocal baryon operators are formulated in a second step as direct products of the spinor structures of smeared, local operators together with gauge-covariant lattice displacements of one or more of the smeared quark fields. Linear combinations of direct products of spinorial and spatial irreducible representations are then formed with appropriate Clebsch-Gordan coefficients of the octahedral group. The construction attempts to maintain maximal overlap with the continuum SU(2) group in order to provide a physically interpretable basis. Nonlocal operators provide direct couplings to states that have nonzero orbital angular momentum.

  11. The algebra of dual -1 Hahn polynomials and the Clebsch-Gordan problem of sl{sub -1}(2)

    Energy Technology Data Exchange (ETDEWEB)

    Genest, Vincent X.; Vinet, Luc [Centre de Recherches Mathematiques, Universite de Montreal, C.P. 6128, Succursale Centre-ville, Montreal, Quebec H3C 3J7 (Canada); Zhedanov, Alexei [Donetsk Institute for Physics and Technology, Donetsk 83114 (Ukraine)

    2013-02-15

    The algebra H of the dual -1 Hahn polynomials is derived and shown to arise in the Clebsch-Gordan problem of sl{sub -1}(2). The dual -1 Hahn polynomials are the bispectral polynomials of a discrete argument obtained from the q{yields}-1 limit of the dual q-Hahn polynomials. The Hopf algebra sl{sub -1}(2) has four generators including an involution, it is also a q{yields}-1 limit of the quantum algebra sl{sub q}(2) and furthermore, the dynamical algebra of the parabose oscillator. The algebra H, a two-parameter generalization of u(2) with an involution as additional generator, is first derived from the recurrence relation of the -1 Hahn polynomials. It is then shown that H can be realized in terms of the generators of two added sl{sub -1}(2) algebras, so that the Clebsch-Gordan coefficients of sl{sub -1}(2) are dual -1 Hahn polynomials. An irreducible representation of H involving five-diagonal matrices and connected to the difference equation of the dual -1 Hahn polynomials is constructed.

  12. Van der Waerden invariant and Wigner coefficients for some compact groups

    International Nuclear Information System (INIS)

    A simple approach is developed for obtaining the general van der Waerden invariant for SU(n). The solution is symmetric within a phase factor and is expressed in terms of elementary scalars. The results are useful for evaluating the general Wigner coefficient or Clebsch-Gordan coefficient. The internal and the external labelling problems are simultaneously solved by exploiting Speiser's theorem. The SU(5) and O(5) van der Waerden invariants are explicitly worked out; and the general O(5) is contained in SU(2) x SU(2) Wigner coefficient is evaluated as well as certain simple classes of O(5) is contained in SU(2) x U(1) Wigner coefficients. (author)

  13. The screen representation of vector coupling coefficients or Wigner 3j symbols: exact computation and illustration of the asymptotic behavior

    CERN Document Server

    Bitencourt, Ana Carla P; Littlejohn, Robert G; Anderson, Roger; Aquilanti, Vincenzo

    2014-01-01

    The Wigner $3j$ symbols of the quantum angular momentum theory are related to the vector coupling or Clebsch-Gordan coefficients and to the Hahn and dual Hahn polynomials of the discrete orthogonal hyperspherical family, of use in discretization approximations. We point out the important role of the Regge symmetries for defining the screen where images of the coefficients are projected, and for discussing their asymptotic properties and semiclassical behavior. Recursion relationships are formulated as eigenvalue equations, and exploited both for computational purposes and for physical interpretations.

  14. New algebraic tables of SU(2) quantities

    International Nuclear Information System (INIS)

    Formulas for Clebsch-Gordan Coefficients, 6-j symbols and 9-j symbols of SU(2) are presented in a ready-to-program way for obtaining algebraic tables. An excerpt of the complete tables are also presented. (Author)

  15. Relativistic Quantum Mechanics of N Particles - The Clebsch-Gordan Method

    CERN Document Server

    Polyzou, W N

    2002-01-01

    A general technique is presented for constructing quantum mechanical theories of a finite number of interacting particles satisfying Poincar\\'e invariance, cluster separability, and the spectral condition. It is distinguished from other solutions of this problem because it does not utilize the existence of kinematic subgroups that arise in Dirac's forms of dynamics. In the generic construction all Poincar\\'e generators have interactions. The central elements of the construction are the representation theory of the Poincar\\'e group, the theory of Birkhoff lattices, and the algebra of asymptotic constants. The role of the dynamics depends on the choice of basis used to label vectors in Poincar\\'e irreducible subspaces. The scattering equivalence and cluster equivalence of the different constructions are established. The dynamical consequences of requiring cluster properties and Poincar\\'e invariance are discussed.

  16. Front-Form Chiral Multiplets

    CERN Document Server

    Gómez-Rocha, María

    2012-01-01

    In this article we point out that the unitary transformation that relates the chiral basis $\\{R; I J^{PC}\\}$ and the $\\{I; ^{2S+1}L_J \\}$ basis, which was already derived for canonical spin in instant form, is also applicable in light-cone representations. From the most general expression for the Clebsch-Gordan coefficients of the Poincar\\'e group one can see that the chiral limit brings the angular momentum coupling into a simple form that permits a clear relation in terms of SU(2) Clebsch-Gordan coefficients. It provides a tool of measurement of chiral symmetry in relativistic composite systems.

  17. The operator method for angular momentum and SU3

    NARCIS (Netherlands)

    Eekelen, H.A.M. van; Ruijgrok, Th.W.

    1966-01-01

    It is well known how Schwinger's1) operator method can be used to construct all representations of the angular momentum operators. We give a brief account of this method and show that it is very convenient for a short derivation of the general Clebsch-Gordan coefficients. The method is then applied

  18. Generalized Uncertainty Principle and Angular Momentum

    CERN Document Server

    Bosso, Pasquale

    2016-01-01

    Various models of quantum gravity suggest a modification of the Heisenberg's Uncertainty Principle, to the so-called Generalized Uncertainty Principle, between position and momentum. In this work we show how this modification influences the theory of angular momentum in Quantum Mechanics. In particular, we compute Planck scale corrections to angular momentum eigenvalues, the Hydrogen atom spectrum, the Stern-Gerlach experiment and the Clebsch-Gordan coefficients. We also examine effects of the Generalized Uncertainty Principle on multi-particle systems.

  19. Invariants, Projection Operators and $SU(N)\\times SU(N)$ Irreducible Schwinger Bosons

    OpenAIRE

    Mathur, Manu; Raychowdhury, Indrakshi; Sreeraj, T.P.

    2011-01-01

    We exploit SU(N) Schwinger bosons to construct and analyze the coupled irreducible representations of $SU(N) \\times SU(N)$ in terms of the invariant group. The corresponding projection operators are constructed in terms of the invariant group generators. We also construct $SU(N) \\times SU(N)$ irreducible Schwinger bosons which directly create these coupled irreducible states. The SU(N) Clebsch Gordan coefficients are computed as the matrix elements of the projection operators.

  20. Configuration space FADDEEV calculations

    International Nuclear Information System (INIS)

    805The detailed study of few-body systems provides one of the most precise tools for studying the dynamics of nuclei. We have investigated the physical and mathematical consequences of using different interactions which fit the same two-body data in three-body models. In addition, new methods for coupling multiquark states such that the resulting state has the correct permutation symmetry have been found. Procedures for computing the Clebsch-Gordan coefficients for these states have been developed

  1. Elasticity tensor and ultrasonic velocities for anisotropic cubic polycrystal

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The orientation distribution of crystallites in a polycrystal can be described by the orientation distribution function(ODF) . The ODF can be expanded under the Wigner D-bases. The expanded coefficients in the ODF are called the texture coefficients. In this paper,we use the Clebsch-Gordan expression to derive an explicit expression of the elasticity tensor for an anisotropic cubic polycrystal. The elasticity tensor contains three material constants and nine texture coefficients. In order to measure the nine texture coefficients by ultrasonic wave,we give relations between the nine texture coefficients and ultrasonic propagation velocities. We also give a numerical example to check the relations.

  2. Self-dual Continuous Series of Representations for U_q(sl(2)) and U_q(osp(1|2))

    CERN Document Server

    Hadasz, Leszek; Schomerus, Volker

    2013-01-01

    We determine the Clebsch-Gordan and Racah-Wigner coefficients for continuous series of representations of the quantum deformed algebras U_q(sl(2)) and U_q(osp(1|2)). While our results for the former algebra reproduce formulas by Ponsot and Teschner, the expressions for the orthosymplectic algebra are new. Up to some normalization factors, the associated Racah-Wigner coefficients are shown to agree with the fusing matrix in the Neveu-Schwarz sector of N=1 supersymmetric Liouville field theory.

  3. Self-dual continuous series of representations for U{sub q}(sl(2)) and U{sub q}(osp(1 vertical stroke 2))

    Energy Technology Data Exchange (ETDEWEB)

    Hadasz, Leszek [Krakow Univ. (Poland). Inst. of Physics; Pawelkiewicz, Michal; Schomerus, Volker [DESY Hamburg (Germany). Theory Group

    2013-05-15

    We determine the Clebsch-Gordan and Racah-Wigner coefficients for continuous series of representations of the quantum deformed algebras U{sub q}(sl(2)) and U{sub q}(osp(1 vertical stroke 2)). While our results for the former algebra reproduce formulas by Ponsot and Teschner, the expressions for the orthosymplectic algebra are new. Up to some normalization factors, the associated Racah-Wigner coefficients are shown to agree with the fusing matrix in the Neveu-Schwarz sector of N=1 supersymmetric Liouville field theory.

  4. Addition theorems for spin spherical harmonics: I. Preliminaries

    Energy Technology Data Exchange (ETDEWEB)

    Bouzas, Antonio O, E-mail: abouzas@mda.cinvestav.mx [Departamento de Fisica Aplicada, CINVESTAV-IPN, Carretera Antigua a Progreso Km. 6, Apdo. Postal 73 ' Cordemex' , Merida 97310, Yucatan (Mexico)

    2011-04-22

    We develop a systematic approach to deriving addition theorems for, and some other bilocal sums of, spin spherical harmonics. In this first part we establish some necessary technical results. We discuss the factorization of orbital and spin degrees of freedom in certain products of Clebsch-Gordan coefficients, and obtain general explicit results for the matrix elements in configuration space of tensor products of arbitrary rank of the position and angular-momentum operators. These results are the basis of the addition theorems for spin spherical harmonics obtained in part II (2011 J. Phys. A: Math. Theor. 44 165302).

  5. A computer code for calculations in the algebraic collective model of the atomic nucleus

    CERN Document Server

    Welsh, T A

    2016-01-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1,1) x SO(5) dynamical group. This, in particular, obviates the use of coefficients of fractional parentage. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [pi x q x pi]_0 and [pi x pi]_{LM}, where q_M are the model's quadrupole moments, and pi_N are corresponding conjugate momenta (-2>=M,N<=2). The code also provides ready access to SO(3)-reduced SO(5) Clebsch-Gordan coefficients through data files provided with the code.

  6. Relativistic quantum mechanics

    CERN Document Server

    Horwitz, Lawrence P

    2015-01-01

    This book describes a relativistic quantum theory developed by the author starting from the E.C.G. Stueckelberg approach proposed in the early 40s. In this framework a universal invariant evolution parameter (corresponding to the time originally postulated by Newton) is introduced to describe dynamical evolution. This theory is able to provide solutions for some of the fundamental problems encountered in early attempts to construct a relativistic quantum theory. A relativistically covariant construction is given for which particle spins and angular momenta can be combined through the usual rotation group Clebsch-Gordan coefficients. Solutions are defined for both the classical and quantum two body bound state and scattering problems. The recently developed quantum Lax-Phillips theory of semigroup evolution of resonant states is described. The experiment of Lindner and coworkers on interference in time is discussed showing how the property of coherence in time provides a simple understanding of the results. Th...

  7. Light baryon spectrum using improved interpolating operators

    Energy Technology Data Exchange (ETDEWEB)

    S. Basak, R. G. Edwards, G. T. Fleming, J. Juge, A. Lichtl, C. Morningstar D. G. Richards, I. Sato, S. J. Wallace

    2006-06-26

    Energies for excited light baryons are computed in quenched QCD with a pion mass of 490 MeV. Operators used in the simulations include local operators and the simplest nonlocal operators that have nontrivial orbital structures. All operators are designed with the use of Clebsch-Gordan coefficients of the octahedral group so that they transform irreducibly under the group rotations. Matrices of correlation functions are computed for each irreducible representation, and then the variational method is applied to separate mass eigenstates. We obtained 17 states for isospin 1/2 and 11 states for isospin 3/2 in various spin-parity channels including J{sup P}=5/2{sup {+-}}. The pattern of the lowest-lying energies from each irrep is discussed. We use anisotropic lattices of volume 24{sup 3} x 64 with temporal lattice spacing a{sub t}{sup -1}=6.05 GeV with renormalized anisotropy xi=3.0.

  8. Magnetic energy cascade in spherical geometry: I. The stellar convective dynamo case

    CERN Document Server

    Strugarek, A; Mathis, S; Sarazin, Y

    2013-01-01

    We present a method to characterize the spectral transfers of magnetic energy between scales in simulations of stellar convective dynamos. The full triadic transfer functions are computed thanks to analytical coupling relations of spherical harmonics based on the Clebsch-Gordan coefficients. The method is applied to mean field $\\alpha\\Omega$ dynamo models as benchmark tests. From the physical standpoint, the decomposition of the dynamo field into primary and secondary dynamo families proves very instructive in the $\\alpha\\Omega$ case. The same method is then applied to a fully turbulent dynamo in a solar convection zone, modeled with the 3D MHD ASH code. The initial growth of the magnetic energy spectrum is shown to be non-local. It mainly reproduces the kinetic energy spectrum of convection at intermediate scales. During the saturation phase, two kinds of direct magnetic energy cascades are observed in regions encompassing the smallest scales involved in the simulation. The first cascade is obtained through ...

  9. Rotationally Invariant Hamiltonians for Nuclear Spectra Based on Quantum Algebras

    CERN Document Server

    Bonatsos, D; Raychev, P P; Terziev, P A; Bonatsos, Dennis

    2002-01-01

    The rotational invariance under the usual physical angular momentum of the SUq(2) Hamiltonian for the description of rotational nuclear spectra is explicitly proved and a connection of this Hamiltonian to the formalisms of Amal'sky and Harris is provided. In addition, a new Hamiltonian for rotational spectra is introduced, based on the construction of irreducible tensor operators (ITO) under SUq(2) and use of q-deformed tensor products and q-deformed Clebsch-Gordan coefficients. The rotational invariance of this SUq(2) ITO Hamiltonian under the usual physical angular momentum is explicitly proved, a simple closed expression for its energy spectrum (the ``hyperbolic tangent formula'') is introduced, and its connection to the Harris formalism is established. Numerical tests in a series of Th isotopes are provided.

  10. Molecular Spectra from Rotationally Invariant Hamiltonians Based on the Quantum Algebra SUq(2) and Irreducible Tensor Operators under SUq(2)

    CERN Document Server

    Bonatsos, D; Raychev, P P; Terziev, P A; Bonatsos, Dennis

    2003-01-01

    The rotational invariance under the usual physical angular momentum of the SUq(2) Hamiltonian for the description of rotational molecular spectra is explicitly proved and a connection of this Hamiltonian to the formalism of Amal'sky is provided. In addition, a new Hamiltonian for rotational spectra is introduced, based on the construction of irreducible tensor operators (ITOs) under SUq(2) and use of q-deformed tensor products and q-deformed Clebsch-Gordan coefficients. The rotational invariance of this SUq(2) ITO Hamiltonian under the usual physical angular momentum is explicitly proved and a simple closed expression for its energy spectrum (the ``hyperbolic tangent formula'') is introduced. Numerical tests against an experimental rotational band of HF are provided.

  11. General utility computer programs for nuclear structure experiments

    International Nuclear Information System (INIS)

    The Nuclear codes package contains several theory programs which allow the calculation of many quantities needed in nuclear structure experiments. These codes were initially created to be run on Vax Machines. Therefore, many errors result at their compilation on Linux Machines. We fixed these errors and verified the result with input parameters that generate known output quantities. The following programs are available on the Linux network at the Department of Nuclear Physics: 1. BASS -Program to calculate fusion barriers and the limiting angular momentum for complete fusion of heavy ions, using the Bass model; 2. BM1BE2 -Program to calculate the ratio of the reduced transition probabilities: B(M1;I→I-1)/B(E2;I→I-2) = 2/2 and the mixing ratio of ΔI = 1 transitions: δ = 0.799· Eγ(MeV)· /. The Program uses the semi-classical formalism of Doenau and Frauendorf. The extension to multi-quasiparticle structures follows Radford's prescription; 3. CLEBSCH -Program to calculate the Clebsch-Gordan coefficients: ; 4. CLEB - Calculates only the following Clebsch-Gordan coefficients: and ; 5. DEDX - Based on an old Oak Ridge code, this program calculates stopping powers and ranges. It works with all chemical elements, plus the compounds ISOBUTANE and MYLAR; 6. EPSBET - The program makes conversion between Nilsson epsilon deformations and Warsaw betas, i.e. shape defined in terms of epsilons will be expanded in terms of betas. Originally written by W. Nazarewicz; 7. GOSTOP - This program allows the calculation of electronic and nuclear stopping powers. Data for the stopper material density are taken from the American Institute of Physics handbook; 8. QUAD - Program which extracts β2 and ε2 values from a given quadrupole moment Q0; 9. STIME Program to calculate stopping times for ions in materials; 10. WU - Program to calculate the reduced electromagnetic transition rates B(EL), B(ML) and the ratios B(EL)/B(EL)W and B(ML)/B(ML)W (in Weiskopf units). (authors)

  12. Interacting boson approximation

    International Nuclear Information System (INIS)

    Lectures notes on the Interacting Boson Approximation are given. Topics include: angular momentum tensors; properties of T/sub i//sup (n)/ matrices; T/sub i//sup (n)/ matrices as Clebsch-Gordan coefficients; construction of higher rank tensors; normalization: trace of products of two s-rank tensors; completeness relation; algebra of U(N); eigenvalue of the quadratic Casimir operator for U(3); general result for U(N); angular momentum content of U(3) representation; p-Boson model; Hamiltonian; quadrupole transitions; S,P Boson model; expectation value of dipole operator; S-D model: U(6); quadratic Casimir operator; an O(5) subgroup; an O(6) subgroup; properties of O(5) representations; quadratic Casimir operator; quadratic Casimir operator for U(6); decomposition via SU(5) chain; a special O(3) decomposition of SU(3); useful identities; a useful property of D/sub αβγ/(α,β,γ = 4-8) as coupling coefficients; explicit construction of T/sub x//sup (2)/ and d/sub αβγ/; D-coefficients; eigenstates of T3; and summary of T = 2 states

  13. A complementary group technique for a resolution of the outer multiplicity problem of SU(n); 1, Littlewood rule and a complementary group of SU(n)

    CERN Document Server

    Pan, F; Pan, Feng

    1998-01-01

    A complementary group to SU(n) is found that realizes all features of the Littlewood rule for Kronecker products of SU(n) representations. This is accomplished by considering a state of SU(n) to be a special Gel'fand state of the complementary group {\\cal U}(2n-2). The labels of {\\cal U}(2n-2) can be used as the outer multiplicity labels needed to distinguish multiple occurrences of irreducible representations (irreps) in the SU(n)\\times SU(n)\\downarrow SU(n) decomposition that is obtained from the Littlewood rule. Furthermore, this realization can be used to determine SU(n)\\supset SU(n-1)\\times U(1) Reduced Wigner Coefficients (RWCs) and Clebsch-Gordan Coefficients (CGCs) of SU(n), using algebraic or numeric methods, in either the canonical or a noncanonical basis. The method is recursive in that it uses simpler RWCs or CGCs with one symmetric irrep in conjunction with standard recoupling procedures. New explicit formulae for the multiplicity for SU(3) and SU(4) are used to illustrate the theory.

  14. Configuration space Faddeev calculations

    International Nuclear Information System (INIS)

    The detailed study of few-body systems provides one of the most effective means for studying nuclear physics at subnucleon distance scales. For few-body systems the model equations can be solved numerically with errors less than the experimental uncertainties. We have used such systems to investigate the size of relativistic effects, the role of meson-exchange currents, and the importance of quark degrees of freedom in the nucleus. Complete calculations for momentum-dependent potentials have been performed, and the properties of the three-body bound state for these potentials have been studied. Few-body calculations of the electromagnetic form factors of the deuteron and pion have been carried out using a front-form formulation of relativistic quantum mechanics. The decomposition of the operators transforming convariantly under the Poincare group into kinematical and dynamical parts has been studies. New ways for constructing interactions between particles, as well as interactions which lead to the production of particles, have been constructed in the context of a relativistic quantum mechanics. To compute scattering amplitudes in a nonperturbative way, classes of operators have been generated out of which the phase operator may be constructed. Finally, we have worked out procedures for computing Clebsch-Gordan and Racah coefficients on a computer, as well as giving procedures for dealing with the multiplicity problem

  15. Population dynamics in a metastable neon magneto-optical trap

    Science.gov (United States)

    Glover, R. D.; Calvert, J. E.; Sang, R. T.

    2013-02-01

    We observe the population dynamics within a metastable neon magneto-optical trap (MOT) through the measurement of the average squared Clebsch-Gordan coefficient C2 over a range of laser detunings. The magnitude of C2 is dependent on the internal quantum state of an atom interacting with the light field and is found to show a strong dependence on the applied laser detuning. Previously it has been reported [Townsend , Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.52.1423 52, 1423 (1995)] that trapped atoms in a MOT are pumped towards the states that interact most strongly with the local field and therefore the measured value of C2 is larger than the average over all possible transitions. For the 3P2-to-3D3 cooling transition in metastable neon the average C2 value is equal to 0.46; however, we have measured 0.29±0.03

  16. Configuration space Faddeev calculations: Progress report for period 1 January 1986-31 December 1986

    International Nuclear Information System (INIS)

    The detailed study of few-body nuclear systems provides a powerful tool to identify the relevant degrees of freedom in the nucleus. For these systems one can perform detailed and accurate numerical calculations which can be used to study the interactions between the various degrees of freedom. We have used these systems to investigate the size of the relativistic effects, the role of meson exchange currents, and the importance of the quark degrees of freedom in the nuclear system. New computational tools have been developed to treat relativistic operators. The effects of the Coulomb polarization potential on the low-energy scattering parameters have been investigated, and the effects of the Coulomb interaction on charge symmetry breaking have been studied. We have continued our project to find representations for multiparticle scattering amplitudes which satisfy certain physical properties. Finally, we have extended our work on the realization of the irreducible representations of compact groups as spaces of polynomials. These realizations can then be used in a symbolic manipulation program to generate Clebsch-Gordan and Racah coefficients for groups important in nuclear physics applications. 37 refs

  17. Nonplanar integrability

    Science.gov (United States)

    Carlson, Warren; de Mello Koch, Robert; Lin, Hai

    2011-03-01

    In this article we study operators with a dimension Δ ˜ O( N) and show that simple analytic expressions for the action of the dilatation operator can be found. The operators we consider are restricted Schur polynomials. There are two distinct classes of operators that we consider: operators labeled by Young diagrams with two long columns or two long rows. The main complication in working with restricted Schur polynomials is in building a projector from a given S n+ m irreducible representation to an S n × S m irreducible representation (both specified by the labels of the restricted Schur polynomial). We give an explicit construction of these projectors by reducing it to the simple problem of addition of angular momentum in ordinary non-relativistic quantum mechanics. The diagonalization of the dilatation operator reduces to solving three term recursion relations. The fact that the recursion relations have only three terms is a direct consequence of the weak mixing at one loop of the restricted Schur polynomials. The recursion relations can be solved exactly in terms of symmetric Kravchuk polynomials or in terms of Clebsch-Gordan coefficients. This proves that the dilatation operator reduces to a decoupled set of harmonic oscillators and therefore it is integrable.

  18. Double groups and projective representations

    Science.gov (United States)

    Altmann, S. L.; Herzig, P.

    Some problems are discussed in relation to the usual treatment of improper groups through their double groups, in particular the identification (rather than the mere isomorphism) of such groups as C3v and D3. The enhancement of SU(2) by the addition of the inversion is analysed for this purpose. This requires a careful discussion of the behaviour of spinors under inversion and two types of spinors are defined, Cartan and Pauli spinors, that behave differently with respect to inversion, although it is shown that this difference merely entails a choice of gauge in the language of projective representations. A distinction is proposed between the inversion operation and the parity operator: when the former is realized as a binary rotation in 4-space, the latter can be identified with its infinitesimal generator. The passage from SO(3) to O(3) (group of all proper and improper rotations) is studied and a hitherto unknown faithful projective representations of O(3) is given. It is shown how spinor representations can be constructed for improper point groups in either the Cartan or Pauli gauges. A choice of gauge is proposed to ensure agreement with current practice in angular momentum theory and with that in single point groups. As an example, Clebsch-Gordan coefficients are constructed for C3v.

  19. New Treatment of Systems of Compounded Angular Momentum

    CERN Document Server

    Mweene, H V

    1999-01-01

    The approach to quantum mechanics which we hav used to derive the matrix treatment of spin from first principles is now employed to treat systems of compounded angular momentum. A general treatment is first given, which is then applied to the concrete cases of a spin-0 and a spin-1 system obtained by adding the spins of two spin-1/2 systems. Thus, the probability amplitudes for measurements on the systems are derived, as well as the matrix vectors and operators corresponding to the systems. The matrix operators and states thereby resulting are different from the standard forms and are much more generalized. The formulas so derived are applied to the case of joint measurements on the subsystems of such a system, a problem made very topical by the great interest in quantum foundations now obtaining. As a consequence of the insights arising from this treatment, we show that the Clebsch-Gordan coefficients are amenable to generalization, and we give the generalized forms for these cases.

  20. Near exact excited states of the carbon dimer in a quadruple-zeta basis using a general non-Abelian density matrix renormalization group algorithm

    CERN Document Server

    Sharma, Sandeep

    2014-01-01

    We extend our previous work [J. Chem. Phys, \\textbf{136}, 124121], which described a spin-adapted (SU(2) symmetry) density matrix renormalization group (DMRG) algorithm, to additionally utilize general non-Abelian point group symmetries. A key strength of the present formulation is that the requisite tensor operators are not hard-coded for each symmetry group, but are instead generated on the fly using the appropriate Clebsch-Gordan coefficients. This allows our single implementation to easily enable (or disable) any non-Abelian point group symmetry (including SU(2) spin symmetry). We use our implementation to compute the ground state potential energy curve of the C$_2$ dimer in the cc-pVQZ basis set (with a frozen-core), corresponding to a Hilbert space dimension of 10$^{12}$ many-body states. While our calculated energy lies within the 0.3 mE$_h$ error bound of previous initiator full configuration interaction quantum Monte Carlo (i-FCIQMC) and correlation energy extrapolation by intrinsic scaling (CEEIS) c...

  1. Boosting Wigner's nj-symbols

    CERN Document Server

    Speziale, Simone

    2016-01-01

    We study the SL(2,C) Clebsch-Gordan coefficients appearing in the lorentzian EPRL spin foam amplitudes for loop quantum gravity. We show how the amplitudes decompose into SU(2) nj-symbols at the vertices and integrals over boosts at the edges. The integrals define edge amplitudes that can be evaluated analytically using and adapting results in the literature, leading to a pure state sum model formulation. This procedure introduces virtual representations which, in a manner reminiscent to virtual momenta in Feynman amplitudes, are off-shell of the simplicity constraints present in the theory, but with the integrands that peak at the on-shell values. We point out some properties of the edge amplitudes which are helpful for numerical and analytical evaluations of spin foam amplitudes, and suggest among other things a simpler model useful for calculations of certain lowest order amplitudes. As an application, we estimate the large spin scaling behaviour of the simpler model, on a closed foam with all 4-valent edg...

  2. A computer code for calculations in the algebraic collective model of the atomic nucleus

    Science.gov (United States)

    Welsh, T. A.; Rowe, D. J.

    2016-03-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1 , 1) × SO(5) dynamical group. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code enables a wide range of model Hamiltonians to be analysed. This range includes essentially all Hamiltonians that are rational functions of the model's quadrupole moments qˆM and are at most quadratic in the corresponding conjugate momenta πˆN (- 2 ≤ M , N ≤ 2). The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [ π ˆ ⊗ q ˆ ⊗ π ˆ ] 0 and [ π ˆ ⊗ π ˆ ] LM. The code is made efficient by use of an analytical expression for the needed SO(5)-reduced matrix elements, and use of SO(5) ⊃ SO(3) Clebsch-Gordan coefficients obtained from precomputed data files provided with the code.

  3. Tensor space representations of Temperley-Lieb algebra via orthogonal projections of rank $r \\geq 1$

    CERN Document Server

    Bytsko, Andrei

    2016-01-01

    Unitary representations of the Temperley-Lieb algebra $TL_N(Q)$ on the tensor space $({\\mathbb C^n})^{\\otimes N}$ are considered. Two criteria are given for determining when an orthogonal projection matrix $P$ of a rank $r$ gives rise to such a representation. The first of them is the equality of traces of certain matrices and the second is the unitary condition for a certain partitioned matrix. Some estimates are obtained on the lower bound of $Q$ for a given dimension $n$ and rank $r$. It is also shown that if $4r>n^2$, then $Q$ can take only a discrete set of values determined by the value of $n^2/r$. In particular, the only allowed value of $Q$ for $n=r=2$ is $Q=\\sqrt{2}$. Finally, properties of the Clebsch-Gordan coefficients of the quantum Hopf algebra $U_q(su_2)$ are used in order to find all $r=1$ and $r=2$ unitary tensor space representations of $TL_N(Q)$ such that $Q$ depends continuously on $q$ and $P$ is the projection in the tensor square of a simple $U_q(su_2)$ module on the subspace spanned by ...

  4. A minimal model of neutrino flavor

    Science.gov (United States)

    Luhn, Christoph; Parattu, Krishna Mohan; Wingerter, Akın

    2012-12-01

    Models of neutrino mass which attempt to describe the observed lepton mixing pattern are typically based on discrete family symmetries with a non-Abelian and one or more Abelian factors. The latter so-called shaping symmetries are imposed in order to yield a realistic phenomenology by forbidding unwanted operators. Here we propose a supersymmetric model of neutrino flavor which is based on the group T 7 and does not require extra {Z} N or U(1) factors in the Yukawa sector, which makes it the smallest realistic family symmetry that has been considered so far. At leading order, the model predicts tribimaximal mixing which arises completely accidentally from a combination of the T 7 Clebsch-Gordan coefficients and suitable flavon alignments. Next-to-leading order (NLO) operators break the simple tribimaximal structure and render the model compatible with the recent results of the Daya Bay and Reno collaborations which have measured a reactor angle of around 9°. Problematic NLO deviations of the other two mixing angles can be controlled in an ultraviolet completion of the model. The vacuum alignment mechanism that we use necessitates the introduction of a hidden flavon sector that transforms under a {Z} 6 symmetry, thereby spoiling the minimality of our model whose flavor symmetry is then T 7 × {Z} 6.

  5. A Minimal Model of Neutrino Flavor

    CERN Document Server

    Luhn, Christoph; Wingerter, Akın

    2012-01-01

    Models of neutrino mass which attempt to describe the observed lepton mixing pattern are typically based on discrete family symmetries with a non-Abelian and one or more Abelian factors. The latter so-called shaping symmetries are imposed in order to yield a realistic phenomenology by forbidding unwanted operators. Here we propose a supersymmetric model of neutrino flavor which is based on the group T7 and does not require extra Z_N or U(1) factors, which makes it the smallest realistic family symmetry that has been considered so far. At leading order, the model predicts tribimaximal mixing which arises completely accidentally from a combination of the T7 Clebsch-Gordan coefficients and suitable flavon alignments. Next-to-leading order (NLO) operators break the simple tribimaximal structure and render the model compatible with the recent results of the Daya Bay and Reno collaborations which have measured a reactor angle of around 9 degrees. Problematic NLO deviations of the other two mixing angles can be cont...

  6. Wave Reflection Coefficient Spectrum

    Institute of Scientific and Technical Information of China (English)

    俞聿修; 邵利民; 柳淑学

    2003-01-01

    The wave reflection coefficient frequency spectrum and directional spectrum for concrete face slope breakwaters and rubble mound breakwaters are investigated through physical model tests in the present study. The reflection coefficients of oblique irregular waves are analyzed by the Modified Two-Point Method (MTPM) proposed by the authors. The results show that the wave reflection coefficient decreases with increasing wave frequency and incident angle or decreasing structure slope. The reflection coefficient frequency spectrum and its variation with Iribarren number are given in this paper. The paper also suggests an empirical 3-dimensional reflection coefficient spectrum, i.e. reflection coefficient directional spectrum, which can be used to illustrate quantitatively the variation of reflection coefficient with the incident angle and the Iribarren number for oblique irregular waves.

  7. Transport Coefficients of Fluids

    CERN Document Server

    Eu, Byung Chan

    2006-01-01

    Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.

  8. Prestarlike functions with negative coefficients

    Directory of Open Access Journals (Sweden)

    H. Silverman

    1979-01-01

    Full Text Available The extreme points for prestarlike functions having negative coefficients are determined. Coefficient, distortion and radii of univalence, starlikeness, and convexity theorems are also obtained.

  9. Gorenstein Hilbert Coefficients

    CERN Document Server

    Khoury, Sabine El

    2012-01-01

    We prove upper and lower bounds for all the coefficients in the Hilbert Polynomial of a graded Gorenstein algebra $S=R/I$ with a quasi-pure resolution over $R$. The bounds are in terms of the minimal and the maximal shifts in the resolution of $R$ . These bounds are analogous to the bounds for the multiplicity found in \\cite{S} and are stronger than the bounds for the Cohen Macaulay algebras found in \\cite{HZ}.

  10. Evidence for a dipolar-coupled AM system in carnosine in human calf muscle from in vivo 1H NMR spectroscopy

    Science.gov (United States)

    Schröder, Leif; Bachert, Peter

    2003-10-01

    Spin systems with residual dipolar couplings such as creatine, taurine, and lactate in skeletal muscle tissue exhibit first-order spectra in in vivo 1H NMR spectroscopy at 1.5 T because the coupled protons are represented by (nearly) symmetrized eigenfunctions. The imidazole ring protons (H2, H4) of carnosine are suspected to form also a coupled system. The ring's stiffness could enable a connectivity between these anisochronous protons with the consequence of second-order spectra at low field strength. Our purpose was to study whether this deviation from the Paschen-Back condition can be used to detect the H2-H4 coupling in localized 1D 1H NMR spectra obtained at 1.5 T (64 MHz) from the human calf in a conventional whole-body scanner. As for the hydrogen hyperfine interaction, a Breit-Rabi equation was derived to describe the transition from Zeeman to Paschen-Back regime for two dipolar-coupled protons. The ratio of the measurable coupling strength ( Sk) and the difference in resonance frequencies of the coupled spins (Δ ω) induces quantum-state mixing of various degree upon definition of an appropriate eigenbase of the coupled spin system. The corresponding Clebsch-Gordan coefficients manifest in characteristic energy corrections in the Breit-Rabi formula. These additional terms were used to define an asymmetry parameter of the line positions as a function of Sk and Δ ω. The observed frequency shifts of the resonances were found to be consistent with this parameter within the accuracy achievable in in vivo NMR spectroscopy. Thus it was possible to identify the origin of satellite peaks of H2, H4 and to describe this so far not investigated type of residual dipolar coupling in vivo.

  11. The Truth About Ballistic Coefficients

    CERN Document Server

    Courtney, Michael

    2007-01-01

    The ballistic coefficient of a bullet describes how it slows in flight due to air resistance. This article presents experimental determinations of ballistic coefficients showing that the majority of bullets tested have their previously published ballistic coefficients exaggerated from 5-25% by the bullet manufacturers. These exaggerated ballistic coefficients lead to inaccurate predictions of long range bullet drop, retained energy and wind drift.

  12. On the Kendall Correlation Coefficient

    OpenAIRE

    Stepanov, Alexei

    2015-01-01

    In the present paper, we first discuss the Kendall rank correlation coefficient. In continuous case, we define the Kendall rank correlation coefficient in terms of the concomitants of order statistics, find the expected value of the Kendall rank correlation coefficient and show that the later is free of n. We also prove that in continuous case the Kendall correlation coefficient converges in probability to its expected value. We then propose to consider the expected value of the Kendall rank ...

  13. Operator properties of generalized coherent state systems

    Indian Academy of Sciences (India)

    N Mukunda

    2001-02-01

    The main properties of standard quantum mechanical coherent states and the two generalizations of Klauder and of Perelomov are reviewed. For a system of generalized coherent states in the latter sense, necessary and sufficient conditions for existence of a diagonal coherent stable representation for all Hilbert-Schmidt operators are obtained. The main ingredients are Clebsch-Gordan theory and induced representation theory.

  14. On the relation between the modular double of U{sub q}(sl(2,R)) and the quantum Teichmueller theory

    Energy Technology Data Exchange (ETDEWEB)

    Nidaiev, Iurii; Teschner, Joerg

    2013-02-15

    We exhibit direct relations between the modular double of U{sub q}(sl(2,R)) and the quantum Teichmueller theory. Explicit representations for the fusion- and braiding operations of the quantum Teichmueller theory are immediate consequences. Our results include a simplified derivation of the Clebsch-Gordan decomposition for the principal series of representation of the modular double of U{sub q}(sl(2,R)).

  15. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav

    2009-09-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

  16. Measuring of heat transfer coefficient

    DEFF Research Database (Denmark)

    Henningsen, Poul; Lindegren, Maria

    Subtask 3.4 Measuring of heat transfer coefficient Subtask 3.4.1 Design and setting up of tests to measure heat transfer coefficient Objective: Complementary testing methods together with the relevant experimental equipment are to be designed by the two partners involved in order to measure...... the heat transfer coefficient for a wide range of interface conditions in hot and warm forging processes. Subtask 3.4.2 Measurement of heat transfer coefficient The objective of subtask 3.4.2 is to determine heat transfer values for different interface conditions reflecting those typically operating in hot...

  17. Determination Permeability Coefficient from Piezocone

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2014-01-01

    Full Text Available The permeability coefficient of soil profile is one of the problems concerned by engineers, and the determination of permeability coefficient method mainly relies on the laboratory permeability test and field pumping test, but these tests are time-consuming and inefficient, and especially the permeability coefficient of soil under the condition of partial drainage was difficult to determine; in this paper, the modern digital CPTU technology was used. Dimensional permeability KT was defined by using the dimensionless normalized cone tip resistance Qt, friction factor Fr, and pore pressure ratio Bq, these parameters enable plots of Bq-Qt, Fr-Qt, Bq-Fr to be contoured KT and hence for permeability coefficient. The relationship has been applied to Nanjing 4th Yangtze river bridge, and compared with laboratory penetration test. The results indicate that the method can accurately determine the permeability coefficient of soil under partial drainage condition and provide the theoretical basis for engineering application.

  18. Wrong Signs in Regression Coefficients

    Science.gov (United States)

    McGee, Holly

    1999-01-01

    When using parametric cost estimation, it is important to note the possibility of the regression coefficients having the wrong sign. A wrong sign is defined as a sign on the regression coefficient opposite to the researcher's intuition and experience. Some possible causes for the wrong sign discussed in this paper are a small range of x's, leverage points, missing variables, multicollinearity, and computational error. Additionally, techniques for determining the cause of the wrong sign are given.

  19. Transport coefficients of heavy baryons

    Science.gov (United States)

    Tolos, Laura; Torres-Rincon, Juan M.; Das, Santosh K.

    2016-08-01

    We compute the transport coefficients (drag and momentum diffusion) of the low-lying heavy baryons Λc and Λb in a medium of light mesons formed at the later stages of high-energy heavy-ion collisions. We employ the Fokker-Planck approach to obtain the transport coefficients from unitarized baryon-meson interactions based on effective field theories that respect chiral and heavy-quark symmetries. We provide the transport coefficients as a function of temperature and heavy-baryon momentum, and analyze the applicability of certain nonrelativistic estimates. Moreover we compare our outcome for the spatial diffusion coefficient to the one coming from the solution of the Boltzmann-Uehling-Uhlenbeck transport equation, and we find a very good agreement between both calculations. The transport coefficients for Λc and Λb in a thermal bath will be used in a subsequent publication as input in a Langevin evolution code for the generation and propagation of heavy particles in heavy-ion collisions at LHC and RHIC energies.

  20. Estimating the Polyserial Correlation Coefficient.

    Science.gov (United States)

    Bedrick, Edward J.; Breslin, Frederick C.

    1996-01-01

    Simple noniterative estimators of the polyserial correlation coefficient are developed by exploiting a general relationship between the polyserial correlation and the point polyserial correlation to give extensions of the biserial estimators of K. Pearson (1909), H. E. Brogden (1949), and F. M. Lord (1963) to the multicategory setting. (SLD)

  1. Study of Dispersion Coefficient Channel

    Science.gov (United States)

    Akiyama, K. R.; Bressan, C. K.; Pires, M. S. G.; Canno, L. M.; Ribeiro, L. C. L. J.

    2016-08-01

    The issue of water pollution has worsened in recent times due to releases, intentional or not, of pollutants in natural water bodies. This causes several studies about the distribution of pollutants are carried out. The water quality models have been developed and widely used today as a preventative tool, ie to try to predict what will be the concentration distribution of constituent along a body of water in spatial and temporal scale. To understand and use such models, it is necessary to know some concepts of hydraulic high on their application, including the longitudinal dispersion coefficient. This study aims to conduct a theoretical and experimental study of the channel dispersion coefficient, yielding more information about their direct determination in the literature.

  2. Clustering Coefficients in Multiplex Networks

    CERN Document Server

    Cozzo, Emanuele; De Domenico, Manlio; Solé, Albert; Arenas, Alex; Gómez, Sergio; Porter, Mason A; Moreno, Yamir

    2013-01-01

    Recent advances in the study of complex networked systems has highlighted that our interconnected world is made of networks that are coupled together through different layers that each stand for one type of interaction or system. Despite this situation, it is traditional to aggregate multiplex data into a single weighted network in order take advantage of existing tools. This is admittedly convenient, but it is also extremely problematic. In this paper, we generalize the concept of clustering coefficients for multiplex networks. We show how the layered structure of multiplex networks introduces a new degree of freedom that has a fundamental effect on transitivity. We compute our new multiplex clustering coefficients for several real multiplex networks and illustrate why generalizing monoplex concepts to multiplex networks must be done with great care.

  3. Reproducibility of The Random Incidence Absorption Coefficient Converted From the Sabine Absorption Coefficient

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Chang, Ji-ho

    2015-01-01

    Absorption coefficients measured in reverberation chambers, Sabine absorption coefficients, suffer from two major problems. Firstly, they sometimes exceed unity. Secondly, the reproducibility of the Sabine absorption coefficients is quite poor, meaning that the Sabine absorption coefficients vary...

  4. Conditioning of Piezoresistance Coefficient Extraction

    OpenAIRE

    Gniazdowski, Zenon; Koszur, Jan; Kowalski, Pawel

    2016-01-01

    The necessary and sufficient condition for the piezoresistance coefficient extraction and conditioning of the extraction problem are considered as a problem of the certain matrix A. This matrix is implied by the stress distribution on the certain test structure. For the given test structure matrix A was calculated and the condition number was estimated. Obtained value of condition number shows that proposed test structure gives well-conditioned matrix A. Both the geometrical analysis and nume...

  5. Dependence of the coefficient of ultrasonic velocity on the coefficient of free length in organic liquids

    Institute of Scientific and Technical Information of China (English)

    LU Yigang; PENG Jianxin; TONG Jie; DONG Yanwu

    2000-01-01

    On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity and the pressure coefficient of free length, and the relationship between the temperature coefficient of ultrasonic velocity and the temperature coefficient of free length were studied. Relevant equations were given, and the pressure coefficient and temperature coefficient of ultrasonic velocity were calculated, which are in agreement with the measured values.

  6. Matrix Fourier transform with discontinuous coefficients

    OpenAIRE

    Yaremko, O.; Zhuravleva, E.

    2013-01-01

    The explicit construction of direct and inverse Fourier's vector transform with discontinuous coefficients is presented. The technique of applying Fourier's vector transform with discontinuous coefficients for solving problems of mathematical physics.Multidimensional integral transformations with non-separated variables for problems with discontinuous coefficients are constructed in this work. The coefficient discontinuities focused on the of parallel hyperplanes. In this work explicit formul...

  7. Higher Order Macro Coefficients in Periodic Homogenization

    Science.gov (United States)

    Conca, Carlos; San Martin, Jorge; Smaranda, Loredana; Vanninathan, Muthusamy

    2011-09-01

    A first set of macro coefficients known as the homogenized coefficients appear in the homogenization of PDE on periodic structures. If energy is increased or scale is decreased, these coefficients do not provide adequate approximation. Using Bloch decomposition, it is first realized that the above coefficients correspond to the lowest energy and the largest scale. This naturally paves the way to introduce other sets of macro coefficients corresponding to higher energies and lower scales which yield better approximation. The next task is to compare their properties with those of the homogenized coefficients. This article reviews these developments along with some new results yet to be published.

  8. Higher Order Macro Coefficients in Periodic Homogenization

    Energy Technology Data Exchange (ETDEWEB)

    Conca, Carlos; San Martin, Jorge [Departamento de IngenierIa Matematica, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile and Centro de Modelamiento Matematico, UMR 2071 CNRS-UChile, Casilla 170/3 - Correo 3, Santiago (Chile); Smaranda, Loredana [Department of Mathematics, Faculty of Mathematics and Computer Science, University of Pitesti, 110040 Pitesti, Str. Targu din Vale Nr.1, Arges (Romania); Vanninathan, Muthusamy, E-mail: cconca@dim.uchile.cl, E-mail: jorge@dim.uchile.cl, E-mail: smaranda@dim.uchile.cl, E-mail: vanni@math.tifrbng.res.in [TIFR-CAM, Post Bag 6503, GKVK Post, Bangalore - 560065 (India)

    2011-09-15

    A first set of macro coefficients known as the homogenized coefficients appear in the homogenization of PDE on periodic structures. If energy is increased or scale is decreased, these coefficients do not provide adequate approximation. Using Bloch decomposition, it is first realized that the above coefficients correspond to the lowest energy and the largest scale. This naturally paves the way to introduce other sets of macro coefficients corresponding to higher energies and lower scales which yield better approximation. The next task is to compare their properties with those of the homogenized coefficients. This article reviews these developments along with some new results yet to be published.

  9. Note on Two Generalizations of Coefficient Alpha.

    Science.gov (United States)

    Raju, Nambury S.

    1979-01-01

    An important relationship is given for two generalizations of coefficient alpha: (1) Rajaratnam, Cronbach, and Gleser's generalizability formula for stratified-parallel tests, and (2) Raju's coefficient beta. (Author/CTM)

  10. Index-free Heat Kernel Coefficients

    CERN Document Server

    De van Ven, A E M

    1998-01-01

    Using index-free notation, we present the diagonal values of the first five heat kernel coefficients associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient appears here for the first time. For a flat space with a gauge connection, the sixth coefficient is given too. Also provided are the leading terms for any coefficient, both in ascending and descending powers of the Yang-Mills and Riemann curvatures, to the same order as required for the fourth coefficient. These results are obtained by directly solving the relevant recursion relations, working in Fock-Schwinger gauge and Riemann normal coordinates. Our procedure is thus noncovariant, but we show that for any coefficient the `gauged' respectively `curved' version is found from the corresponding `non-gauged' respectively `flat' coefficient by making some simple covariant substitutions. These substitutions being understood, the coefficients retain their `flat' form and size. In this sense the fift...

  11. A general non-Abelian density matrix renormalization group algorithm with application to the C{sub 2} dimer

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sandeep, E-mail: sanshar@gmail.com [Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-01-14

    We extend our previous work [S. Sharma and G. K.-L. Chan, J. Chem. Phys. 136, 124121 (2012)], which described a spin-adapted (SU(2) symmetry) density matrix renormalization group algorithm, to additionally utilize general non-Abelian point group symmetries. A key strength of the present formulation is that the requisite tensor operators are not hard-coded for each symmetry group, but are instead generated on the fly using the appropriate Clebsch-Gordan coefficients. This allows our single implementation to easily enable (or disable) any non-Abelian point group symmetry (including SU(2) spin symmetry). We use our implementation to compute the ground state potential energy curve of the C{sub 2} dimer in the cc-pVQZ basis set (with a frozen-core), corresponding to a Hilbert space dimension of 10{sup 12} many-body states. While our calculated energy lies within the 0.3 mE{sub h} error bound of previous initiator full configuration interaction quantum Monte Carlo and correlation energy extrapolation by intrinsic scaling calculations, our estimated residual error is only 0.01 mE{sub h}, much more accurate than these previous estimates. Due to the additional efficiency afforded by the algorithm, the excitation energies (T{sub e}) of eight lowest lying excited states: a{sup 3}Π{sub u}, b{sup 3}Σ{sub g}{sup −}, A{sup 1}Π{sub u}, c{sup 3}Σ{sub u}{sup +}, B{sup 1}Δ{sub g}, B{sup ′1}Σ{sub g}{sup +}, d{sup 3}Π{sub g}, and C{sup 1}Π{sub g} are calculated, which agree with experimentally derived values to better than 0.06 eV. In addition, we also compute the potential energy curves of twelve states: the three lowest levels for each of the irreducible representations {sup 1}Σ{sub g}{sup +}, {sup 1}Σ{sub u}{sup +}, {sup 1}Σ{sub g}{sup −}, and {sup 1}Σ{sub u}{sup −}, to an estimated accuracy of 0.1 mE{sub h} of the exact result in this basis.

  12. Quantum algebra U{sub qp}(u{sub 2}) and application to the rotational collective dynamics of the nuclei; Algebre quantique U{sub qp}(u{sub 2}) et application a la dynamique collective de rotation dans les noyaux

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, R.

    1995-09-22

    This thesis concerns some aspects of new symmetries in Nuclear Physics. It comprises three parts. The first one is devoted to the study of the quantum algebra U{sub qp}(u{sub 2}). More precisely, we develop its Hopf algebraic structure and we study its co-product structure. The bases of the representation theory of U{sub qp}(u{sub 2}) are introduced. On one hand, we construct the finite-dimensional irreducible representations of U{sub qp}(u{sub 2}). On the other hand, we calculate the Clebsch-Gordan coefficients with the projection operator method. To complete our study, we construct some deformed boson mappings of the quantum algebras U{sub qp}(u{sub 2}), U{sub q{sup 2}}(su{sub 2}) and U{sub qp}(u{sub 1,1}). The second part deals with the construction of a new phenomenological model of the non rigid rotator. This model is based on the quantum algebra U{sub qp}(u{sub 2}). The rotational energy and the E2 reduced transition probabilities are obtained. They depend on the two deformation parameters q and p of the quantum algebra. We show how the use of the two-parameter deformation of the algebra U{sub qp}(u{sub 2}) leads to a generalization of the U{sub q}(su{sub 2})-rotator model. We also introduce a new model of the anharmonic oscillator on the basis of the quantum algebra U{sub qp}(u{sub 2}). We show that the system of the U{sub q}(su{sub 2})-rotator and of the anharmonic oscillator can be coupled with the use of the deformation parameters of U{sub qp}(u{sub 2}). A ro-vibration energy formula and expansion `a la` Dunham are obtained. The aim of the last part is to apply our non rigid rotator model to the rotational collective dynamics of the superdeformed nuclei of the A{approx}130 - 150 and A{approx}190 mass regions and deformed nuclei of the actinide and rare earth series. We adjust the free parameters of our model and compare our results with those from four other models of the non rigid rotator. A comparative analysis is given in terms of transition energies.

  13. Continuous quantum mechanics of single particles in closed and quasi-closed systems: Pt. III and IV

    International Nuclear Information System (INIS)

    The rigorous solution to Schroedinger's nonrelativistic time-dependent equation of a single electron's spin-orbit or magnetic hyperfine interaction reveals the full dynamics of angular momentum coupling especially in the presence of an external, arbitrarily oriented magnetic field. Besides of making a description of major dynamical properties possible in simple classical terms, it also sheds new light on the seeming quantization of states: They turn out to be exceptional states of dynamical balance, which in the field-free case are only made possible by the respective pairs of Clebsch-Gordan coefficients. Moreover, the results not only show that integer and half-integer quantum numbers of the total angular momentum only apply to this special case but that in the general case they are also able to obtain the well-known splitting pattern of the stationary energy levels in the field as produced by separately identifiable, field-dependent contributions from the spin-orbit or the magnetic hyperfine interactions on the one hand, and the magnetic dipole interaction with external magnetic fields on the other in a way not accessible to the Breit-Rabi formula. The results further demonstrate that the total magnetic moment responds quite sensitively to even weak field strengths, i.e., with substantial changes although the linear Zeeman effect suggests their seeming constancy in low fields also for levels with vertical stroke MJ vertical stroke < l+1/2. Although Schroedinger's equation is equivalent to an energy representation this detailed description of the behavior of the total magnetic moment is made possible by the fortunate fact that the coupling magnetic moments enter the Hamiltonian linearly. This circumstance can be exploited to describe in full detail how the total magnetic moment behaves in an arbitrarily oriented magnetic field. It is found that its motion in this environment consists of a basic Larmor precession about the field direction superimposed on which is

  14. Continuous quantum mechanics of single particles in closed and quasi-closed systems: Pt. III and IV

    Energy Technology Data Exchange (ETDEWEB)

    Brieger, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Technische Physik

    2005-07-01

    The rigorous solution to Schroedinger's nonrelativistic time-dependent equation of a single electron's spin-orbit or magnetic hyperfine interaction reveals the full dynamics of angular momentum coupling especially in the presence of an external, arbitrarily oriented magnetic field. Besides of making a description of major dynamical properties possible in simple classical terms, it also sheds new light on the seeming quantization of states: They turn out to be exceptional states of dynamical balance, which in the field-free case are only made possible by the respective pairs of Clebsch-Gordan coefficients. Moreover, the results not only show that integer and half-integer quantum numbers of the total angular momentum only apply to this special case but that in the general case they are also able to obtain the well-known splitting pattern of the stationary energy levels in the field as produced by separately identifiable, field-dependent contributions from the spin-orbit or the magnetic hyperfine interactions on the one hand, and the magnetic dipole interaction with external magnetic fields on the other in a way not accessible to the Breit-Rabi formula. The results further demonstrate that the total magnetic moment responds quite sensitively to even weak field strengths, i.e., with substantial changes although the linear Zeeman effect suggests their seeming constancy in low fields also for levels with vertical stroke M{sub J} vertical stroke < l+1/2. Although Schroedinger's equation is equivalent to an energy representation this detailed description of the behavior of the total magnetic moment is made possible by the fortunate fact that the coupling magnetic moments enter the Hamiltonian linearly. This circumstance can be exploited to describe in full detail how the total magnetic moment behaves in an arbitrarily oriented magnetic field. It is found that its motion in this environment consists of a basic Larmor precession about the field direction

  15. Numerical investigation of NeI for 2p55g configuration and ArI for 3p55g configuration Zeeman structure

    International Nuclear Information System (INIS)

    Full text: The behavior of an atom in the magnetic field can be studied numerically based on the parameters of the fine structure (the radial integrals in the energy operator matrix). A set of the fine structure parameters ensuring the correlation with experimentally observed energies was obtained in the previous works of the authors. The authors provide the results of the numerical study of magnetic sublevels behavior for NeI and ArI (of specified configurations) in the magnetic fields up to 150 kOe. Using the free momentums representation and the Clebsch-Gordan coefficients the authors succeeded to obtain the expressions for the diagonal and non-diagonal elements of the atom-field interaction matrices in LSJM-representation as well as to refine the signs of the non-diagonal elements. (γψi|W|γψi) = (((J(J + 1) + L(L + 1) - S (S +1)/2J(J + 1))gl + ((J(J + 1) - L(L + 1) + S (S +1)/2J(J + 1))gs)) μ0H M (ΔJ 0 ΔL = ΔS = 0 ; (γψi|W|γ'ψj) √[((J - L + S + 1)(J + L - S + 1)(J + L + S + 2)(L + S - J))/4(J + 1)2(2J + 1)(2J + 3) x ((J + 1)2 - M2 x (gl - gs)μ0H] (ΔJ 0 ±1, ΔL ΔS = 0, Jmin). The energies of Zeeman's sublevels were calculated by means of the diagonalization of the complete energy operator matrix, which was expressed in LS-representation with additional elements accounting for the atom-field interaction. The diagonalization was carried out for all the values of the magnetic quantum number M. The distinctive details of Zeemann's structure especially points of crossing and anticrossing areas of magnetic sublevels were obtained for 2p55g configuration of NeI and 3p55g configuration of ArI. (author)

  16. Coefficient of Partial Correlation and Its Calculation

    Institute of Scientific and Technical Information of China (English)

    段全才; 张保法

    1992-01-01

    This thesis offers the general concept of coefficient of partial correlation.Starting with regres-sion analysis,the paper,by using samples,infers the general formula of expressing coefficient of partial correlation by way of simple correlation coefficient.

  17. Is the G Index a Correlation Coefficient?

    Science.gov (United States)

    Vegelius, Jan

    1980-01-01

    One argument against the G index is that, unlike phi, it is not a correlation coefficient; yet, G conforms to the Kendall and E-coefficient definitions. The G index is also equal to the Pearson product moment correlation coefficient obtained from double scoring. (Author/CP)

  18. Diffusion coefficient in photon diffusion theory

    NARCIS (Netherlands)

    Graaff, R; Ten Bosch, JJ

    2000-01-01

    The choice of the diffusion coefficient to be used in photon diffusion theory has been a subject of discussion in recent publications on tissue optics. We compared several diffusion coefficients with the apparent diffusion coefficient from the more fundamental transport theory, D-app. Application to

  19. Innovative Correlation Coefficient Measurement with Fuzzy Data

    OpenAIRE

    Berlin Wu; Chin Feng Hung

    2016-01-01

    Correlation coefficients are commonly found with crisp data. In this paper, we use Pearson’s correlation coefficient and propose a method for evaluating correlation coefficients for fuzzy interval data. Our empirical studies involve the relationship between mathematics achievement and other projects.

  20. Note on Methodology: The Coefficient of Variation.

    Science.gov (United States)

    Sheret, Michael

    1984-01-01

    Addresses applications of the coefficient of variation as a measure of educational inequality or as a means of measuring changes of inequality status. Suggests the Gini coefficient has many advantages over the coefficient of variation since it can be used with the Lorenz curve (Lorenz provides detail Gini omits). (BRR)

  1. Transport coefficients of relativistic systems

    International Nuclear Information System (INIS)

    It becomes increasingly important to know the strength of dissipative effects in relativistic hydrodynamics. Recently, scientists have strongly focused on shear viscosity. Nevertheless, heat flow, being proportional to spatial gradients of e.g. chemical potential over temperature, can also be an important effect in studies of relativistic fluid dynamics. We investigated the heat conductivity coefficient for an ultrarelativistic Boltzmann-gas, using our partonic transport model BAMPS. BAMPS solves the relativistic Boltzmann-equation numerically for arbitrary different particle species. We use pQCD scattering cross-sections. Furthermore, the response of a charged, relativistic gas onto an external electric field determines the electric conductivity. We investigated the electric conductivity of different model systems using three different methods: analytic transport theory, linear response via Green-Kubo formulae in equilibrium BAMPS-setups, and applying the textbook-picture of linear response to BAMPS. We plan to investigate the electric conductivity with the recently improved 2<->3 processes from BAMPS and compare the results with lattice QCD.

  2. Justification for change in AXAIR dispersion coefficients

    International Nuclear Information System (INIS)

    AXAIR is the primary dose assessment code used at the Savannah River Site (SRS) to predict doses following hypothetical releases of relatively short durations. The atmospheric dispersion coefficients currently used in AXAIR are analytical expressions developed to fit the curves in the Turner Workbook as referred to in USNRC Regulatory Guide 1.145. This report explores the ramifications and benefits of changing the dispersion coefficients to a combination of Pasquill's lateral dispersion coefficients and Briggs' vertical dispersion coefficients. The differences in the dispersion coefficients have a minor effect on the relative air concentrations for stability classes A--D, but a significant difference is seen for classes E, F, and G

  3. A drying coefficient for building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2009-01-01

    characterisation of building materials on which the attempt is based to standardize the drying experiment as well as to derive a single number material coefficient. The drying itself is briefly reviewed and existing approaches are discussed. On this basis, possible definitions are evaluated. Finally, a drying...... coefficient is defined which can be determined based on measured drying data. The correlation of this coefficient with the water absorption and the vapour diffusion coefficient is analyzed and its additional information content is critically challenged. As result, a drying coefficient has been derived......The drying experiment is an important element of the hygrothermal characterisation of building materials. Contrary to other moisture transport experiments as the vapour diffusion and the water absorption test, it is until now not possible to derive a simple coefficient for the drying. However...

  4. INVERSE COEFFICIENT PROBLEMS FOR PARABOLIC HEMIVARIATIONAL INEQUALITIES

    Institute of Scientific and Technical Information of China (English)

    Liu Zhenhai; I.Szántó

    2011-01-01

    This paper is devoted to the class of inverse problems for a nonlinear parabolic hemivariational inequality.The unknown coefficient of the operator depends on the gradient of the solution and belongs to a set of admissible coefficients.It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence.Based on this result the existence of a quasisolution of the inverse problem is obtained.

  5. The Intuitionistic Fuzzy Normed Space of Coefficients

    OpenAIRE

    Bilalov, B. T.; S. M. Farahani; Guliyeva, F. A.

    2012-01-01

    Intuitionistic fuzzy normed space is defined using concepts of $t$ -norm and $t$ -conorm. The concepts of fuzzy completeness, fuzzy minimality, fuzzy biorthogonality, fuzzy basicity, and fuzzy space of coefficients are introduced. Strong completeness of fuzzy space of coefficients with regard to fuzzy norm and strong basicity of canonical system in this space are proved. Strong basicity criterion in fuzzy Banach space is presented in terms of coefficient operator.

  6. Remarks on the maximum correlation coefficient

    OpenAIRE

    Dembo, Amir; Kagan, Abram; Shepp, Lawrence A.

    2001-01-01

    The maximum correlation coefficient between partial sums of independent and identically distributed random variables with finite second moment equals the classical (Pearson) correlation coefficient between the sums, and thus does not depend on the distribution of the random variables. This result is proved, and relations between the linearity of regression of each of two random variables on the other and the maximum correlation coefficient are discussed.

  7. DIFFERENCE SCHEMES BASING ON COEFFICIENT APPROXIMATION

    Institute of Scientific and Technical Information of China (English)

    MOU Zong-ze; LONG Yong-xing; QU Wen-xiao

    2005-01-01

    In respect of variable coefficient differential equations, the equations of coefficient function approximation were more accurate than the coefficient to be frozen as a constant in every discrete subinterval. Usually, the difference schemes constructed based on Taylor expansion approximation of the solution do not suit the solution with sharp function.Introducing into local bases to be combined with coefficient function approximation, the difference can well depict more complex physical phenomena, for example, boundary layer as well as high oscillatory, with sharp behavior. The numerical test shows the method is more effective than the traditional one.

  8. Index-free Heat Kernel Coefficients

    OpenAIRE

    van de Ven, Anton E. M.

    1997-01-01

    Using index-free notation, we present the diagonal values of the first five heat kernel coefficients associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient appears here for the first time. For a flat space with a gauge connection, the sixth coefficient is given too. Also provided are the leading terms for any coefficient, both in ascending and descending powers of the Yang-Mills and Riemann curvatures, to the same order as require...

  9. Comparing linear probability model coefficients across groups

    DEFF Research Database (Denmark)

    Holm, Anders; Ejrnæs, Mette; Karlson, Kristian Bernt

    2015-01-01

    This article offers a formal identification analysis of the problem in comparing coefficients from linear probability models between groups. We show that differences in coefficients from these models can result not only from genuine differences in effects, but also from differences in one or more...... of the following three components: outcome truncation, scale parameters and distributional shape of the predictor variable. These results point to limitations in using linear probability model coefficients for group comparisons. We also provide Monte Carlo simulations and real examples to illustrate...... these limitations, and we suggest a restricted approach to using linear probability model coefficients in group comparisons....

  10. Magnetoelectric voltage coefficients of magnetoelectric composites

    Institute of Scientific and Technical Information of China (English)

    WAN Yong-ping; ZHONG Zheng; QIU Jin-hao

    2006-01-01

    The magnetoelectric(ME) effect of the particulate magnetostrictive/piezoelectric composite was theoretically studied. The dependence of the ME voltage coefficients on the material properties of the magnetostrictive phase was discussed. The permittivity,permeability and the elastic modulus of the magnetostrictive phase generally have obvious influences on the ME voltage coefficients. The magnetostrictive phase with a large permittivity,large permeability or stiffer modulus will respectively contribute to the higher ME voltage coefficients. For a certain kind of piezoelectric matrix,the ME voltage coefficients can be improved to some extent by choosing those magnetostrictive materials with large permittivity,permeability or high elastic modulus.

  11. Drag Coefficient of Thin Flexible Cylinder

    Science.gov (United States)

    Subramanian, Chelakara; Gurram, Harika

    2015-11-01

    Measurements of drag coefficients of thin flexible cylindrical wires are described for the Reynolds number range between 250 - 1000. Results indicate that the coefficient values are about 20 to 30 percent lower than the reported laminar flow values for rigid cylinders. Possible fluid dynamics mechanism causing the reduction in drag will be discussed.

  12. Graphite friction coefficient for various conditions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The friction coefficient the graphite used in the Tsinghua University 10MW High Tem-perature Gas-Cooled Reactor was analyzed for various conditions. The variation of the graphitefriction coefficient was measured for various sliding velocities, sliding distances, normal loads, en-vironments and temperatures. A scanning elector microscope (SEM) was used to analyze the fric-tion surfaces.

  13. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  14. Friction Coefficient for Quarks in Supergravity Duals

    OpenAIRE

    Antonyan, E.

    2006-01-01

    We study quarks moving in strongly-coupled plasmas that have supergravity duals. We compute the friction coefficient of strings dual to such quarks for general static supergravity backgrounds near the horizon. Our results also show that a previous conjecture on the bound has to be modified and higher friction coefficients can be achieved.

  15. On Burnett coefficients in periodic media

    Science.gov (United States)

    Conca, Carlos; Orive, Rafael; Vanninathan, Muthusamy

    2006-03-01

    The aim of this work is to demonstrate a curious property of general periodic structures. It is well known that the corresponding homogenized matrix is positive definite. We calculate here the next order Burnett coefficients associated with such structures. We prove that these coefficients form a tensor which is negative semidefinite. We also provide some examples showing degeneracy in multidimension.

  16. A gain-coefficient switched Alexandrite laser

    NARCIS (Netherlands)

    Lee, C. J.; van der Slot, P. J. M.; Boller, K. J.

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ

  17. Alternatives to Pearson's and Spearman's Correlation Coefficients

    CERN Document Server

    Smarandache, Florentin

    2008-01-01

    This article presents several alternatives to Pearson's correlation coefficient and many examples. In the samples where the rank in a discrete variable counts more than the variable values, the mixtures that we propose of Pearson's and Spearman's correlation coefficients give better results.

  18. Energy coefficients for a propeller series

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup

    2004-01-01

    of the potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method....

  19. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    S. C. Tripathy; Kiran Jain; A. Bhatnagar

    2000-09-01

    Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change significantly with rising phase of the solar cycle. We also find temporal variations in the rotation rate near the solar surface.

  20. Problems with Discontinuous Diffusion/Dispersion Coefficients

    Directory of Open Access Journals (Sweden)

    Stefano Ferraris

    2012-01-01

    accurate on smooth solutions and based on a special numerical treatment of the diffusion/dispersion coefficients that makes its application possible also when such coefficients are discontinuous. Numerical experiments confirm the convergence of the numerical approximation and show a good behavior on a set of benchmark problems in two space dimensions.

  1. Heat transfer coefficient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1998-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The calculated heat transfer coeeficient has been compared with the Chart correlation of Shah. The Chart Correlation predits too low heat transfer coefficient but the ratio...

  2. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2012-01-01

    the reason for change in effective stress coefficient under stress. Our model suggests that change in effective stress coefficient will be higher at uniaxial stress condition than at hydrostatic condition. We derived equations from the original definition of Biot to estimate effective stress coefficient from......The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describe...... one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...

  3. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describe...... the reason for change in effective stress coefficient under stress. Our model suggests that change in effective stress coefficient will be higher at uniaxial stress condition than at hydrostatic condition. We derived equations from the original definition of Biot to estimate effective stress coefficient from...... one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...

  4. Estimating beta-mixing coefficients via histograms

    CERN Document Server

    McDonald, Daniel J; Schervish, Mark

    2011-01-01

    The literature on statistical learning for time series often assumes asymptotic independence or "mixing" of data sources. Beta-mixing has long been important in establishing the central limit theorem and invariance principle for stochastic processes; recent work has identified it as crucial to extending results from empirical processes and statistical learning theory to dependent data, with quantitative risk bounds involving the actual beta coefficients. There is, however, presently no way to actually estimate those coefficients from data; while general functional forms are known for some common classes of processes (Markov processes, ARMA models, etc.), specific coefficients are generally beyond calculation. We present an l1-risk consistent estimator for the beta-mixing coefficients, based on a single stationary sample path. Since mixing coefficients involve infinite-order dependence, we use an order-d Markov approximation. We prove high-probability concentration results for the Markov approximation and show...

  5. Estimating Tortuosity Coefficients Based on Hydraulic Conductivity.

    Science.gov (United States)

    Carey, Grant R; McBean, Edward A; Feenstra, Stan

    2016-07-01

    While the tortuosity coefficient is commonly estimated using an expression based on total porosity, this relationship is demonstrated to not be applicable (and thus is often misapplied) over a broad range of soil textures. The fundamental basis for a correlation between the apparent diffusion tortuosity coefficient and hydraulic conductivity is demonstrated, although such a relationship is not typically considered. An empirical regression for estimating the tortuosity coefficient based on hydraulic conductivity for saturated, unconsolidated soil is derived based on results from 14 previously reported diffusion experiments performed with a broad range of soil textures. Analyses of these experimental results confirm that total porosity is a poor predictor for the tortuosity coefficient over a large range of soil textures. The apparent diffusion tortuosity coefficient is more reliably estimated based on hydraulic conductivity. PMID:27315019

  6. Discharge coefficient of small sonic nozzles

    Directory of Open Access Journals (Sweden)

    Yin Zhao-Qin

    2014-01-01

    Full Text Available The purpose of this investigation is to understand flow characteristics in mini/micro sonic nozzles, in order to precisely measure and control miniscule flowrates. Experimental and numerical simulation methods have been used to study critical flow Venturi nozzles. The results show that the nozzle’s size and shape influence gas flow characteristics which leading the boundary layer thickness to change, and then impact on the discharge coefficient. With the diameter of sonic nozzle throat decreasing, the discharge coefficient reduces. The maximum discharge coefficient exits in the condition of the inlet surface radius being double the throat diameter. The longer the diffuser section, the smaller the discharge coefficient becomes. Diffuser angle affects the discharge coefficient slightly.

  7. Separation of Discrete Variables in the 2-DIM Finite Oscillator

    Science.gov (United States)

    Atakishiyev, Natig M.; Pogosyan, George S.; Vicent, Luis Edgar; Wolf, Kurt Bernardo

    2002-06-01

    The finite oscillator in two dimensions is a system whose dynamical algebra is so(4); it has a discrete, finite configuration space whose points can be arranged following cartesian or polar coordinates. Its wavefunctions satisfy 'Schrödinger' difference equations; in the cartesian model they are Wigner d-functions involving Kravchuk polynomials, while in the radial model they are su(2) Clebsch-Gordan functions containing dual Hahn polynomials. An su(2) symmetry algebra and group can be imported from the ordinary oscillator; coherent states exist, and a covariant Wigner function on a compact phase space can be formulated.

  8. Development of database on the distribution coefficient. 1. Collection of the distribution coefficient data

    Energy Technology Data Exchange (ETDEWEB)

    Takebe, Shinichi; Abe, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The distribution coefficient is very important parameter for environmental impact assessment on the disposal of radioactive waste arising from research institutes. The literature survey in the country was mainly carried out for the purpose of selecting the reasonable distribution coefficient value on the utilization of this value in the safety evaluation. This report was arranged much informations on the distribution coefficient for inputting to the database for each literature, and was summarized as a literature information data on the distribution coefficient. (author)

  9. Development of database on the distribution coefficient. 1. Collection of the distribution coefficient data

    International Nuclear Information System (INIS)

    The distribution coefficient is very important parameter for environmental impact assessment on the disposal of radioactive waste arising from research institutes. The literature survey in the country was mainly carried out for the purpose of selecting the reasonable distribution coefficient value on the utilization of this value in the safety evaluation. This report was arranged much informations on the distribution coefficient for inputting to the database for each literature, and was summarized as a literature information data on the distribution coefficient. (author)

  10. FRICTION COEFFICIENT OF DIAMOND WIRE SAW

    Directory of Open Access Journals (Sweden)

    Siniša Dunda

    1998-12-01

    Full Text Available In order to estimate the diamond wire saw upon quarrying of dimension stone, it is necessary to know the value of a friction coefficient on the driving pulley of the saw. Therefore the numerical value of the friction coefficient between diamond wire and coating of a driving pulley was determined in experimental way. The experiments were conducted under different working conditions. The resulting average value of the friction coefficient upon working in wet and muddy conditions amounted to µ = 0,32.

  11. Tracking time-varying coefficient-functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.;

    2000-01-01

    is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coefficient functions. Some of the key properties of the modified method......, but otherwise unknown, functions of a low-dimensional input process. These coefficient functions are estimated adaptively and recursively without specifying a global parametric, form, i.e. the method allows for online tracking of the coefficient functions. Essentially, in its most simple form, the method...

  12. Negative normal restitution coefficient for nanocluster collisions

    CERN Document Server

    Brilliantov, Nikolai V

    2010-01-01

    The oblique impact of nanoclusters is studied by means of Molecular Dynamics simulation. Using the standard definition of the normal restitution coefficient $e$ we observe a surprising result, that $e$ becomes negative for large incident angles. We show that this effect may be attributed to the reorientation of the contact plane during collisions, which affects $e$. We propose a modified definition of the normal restitution coefficient $\\Tilde{e}$. This, in contrast to the standard definition, characterizes exclusively the normal motion and is always positive. We develop a simple theoretical model of an oblique impact, which explains the observed behavior of the restitution coefficients and agrees well with the numerical data.

  13. Soccer ball lift coefficients via trajectory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goff, John Eric [Department of Physics, Lynchburg College, Lynchburg, VA 24501 (United States); Carre, Matt J, E-mail: goff@lynchburg.ed [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2010-07-15

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  14. Measuring optical temperature coefficients of Intralipid.

    Science.gov (United States)

    McGlone, V Andrew; Martinsen, Paul; Künnemeyer, Rainer; Jordan, Bob; Cletus, Biju

    2007-05-01

    The temperature sensitivities of absorption and reduced scattering coefficients in the range 700-1000 nm are determined for the liquid phantom Intralipid using spatially resolved continuous wave measurements. The measurements were conducted on a 10 L heated volume of 1% Intralipid subjected to a 40-30 degrees C cooling regime. The temperature sensitivities of the absorbance coefficients are similar to that expected for pure water. However, the reduced scattering coefficients are more sensitive than can be explained by temperature related density changes, and show an unexpected relationship with wavelength. We have also found that temperature perturbations provide a useful means to evaluate instrument model performance. PMID:17440240

  15. Inferences on the common coefficient of variation.

    Science.gov (United States)

    Tian, Lili

    2005-07-30

    The coefficient of variation is often used as a measure of precision and reproducibility of data in medical and biological science. This paper considers the problem of making inference about the common population coefficient of variation when it is a priori suspected that several independent samples are from populations with a common coefficient of variation. The procedures for confidence interval estimation and hypothesis testing are developed based on the concepts of generalized variables. The coverage properties of the proposed confidence intervals and type-I errors of the proposed tests are evaluated by simulation. The proposed methods are illustrated by a real life example.

  16. Measuring optical temperature coefficients of Intralipid (registered)

    International Nuclear Information System (INIS)

    The temperature sensitivities of absorption and reduced scattering coefficients in the range 700-1000 nm are determined for the liquid phantom Intralipid (registered) using spatially resolved continuous wave measurements. The measurements were conducted on a 10 L heated volume of 1% Intralipid (registered) subjected to a 40-30 deg. C cooling regime. The temperature sensitivities of the absorbance coefficients are similar to that expected for pure water. However, the reduced scattering coefficients are more sensitive than can be explained by temperature related density changes, and show an unexpected relationship with wavelength. We have also found that temperature perturbations provide a useful means to evaluate instrument model performance

  17. Effective Diffusion Coefficients in Coal Chars

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Jensen, Anker

    2001-01-01

    Knowledge of effective diffusion coefficients in char particles is important when interpreting experimental reactivity measurements and modeling char combustion or NO and N2O reduction. In this work, NO and N2O reaction with a bituminous coal char was studied in a fixed-bed quartz glass reactor....... Particle sizes in the range 0.05-5 mm were tested, and the effective diffusion coefficients were estimated from measured effectiveness factors using the Thiele modulus. At 1079 K the effective diffusion coefficients were 5.5 X 10(-6) m(2)/s and 6.8 X 10(-6) m(2)/s for N2O and NO, respectively....... The experimental results were compared with theoretical values calculated from the mean pore radius and the cross-linked pore model. The method of mean pore radius underestimated the effective diffusion coefficient more than an order of magnitude. Using the cross-linked pore model, the bimodal pore size...

  18. Cohomology with Coefficients for Operadic Coalgebras

    Indian Academy of Sciences (India)

    Anita Majumdar; Donald Yau

    2009-09-01

    Corepresentations of a coalgebra over a quadratic operad are defined, and various characterizations of them are given. Cohomology of such an operadic coalgebra with coefficients in a corepresentation is then studied.

  19. Long range interaction coefficients for ytterbium dimers

    CERN Document Server

    Porsev, S G; Derevianko, A; Clark, Charles W

    2013-01-01

    We evaluate the electric-dipole and electric-quadrupole static and dynamic polarizabilities for the 6s^2 ^1S_0, 6s6p ^3P_0, and 6s6p ^3P_1 states and estimate their uncertainties. A methodology is developed for an accurate evaluation of the van der Waals coefficients of dimers involving excited state atoms with strong decay channel to the ground state. This method is used for evaluation of the long range interaction coefficients of particular experimental interest, including the C_6 coefficients for the Yb-Yb ^1S_0+^3P_{0,1} and ^3P_0+^3P_0 dimers and C_8 coefficients for the ^1S_0+^1S_0 and ^1S_0+^3P_1 dimers.

  20. Heat transfer coefficient of cryotop during freezing.

    Science.gov (United States)

    Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

    2013-01-01

    Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).

  1. Torsion method for measuring piezooptic coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Skab, I.; Smaga, I.; Savaryn, V.; Vasylkiv, Yu.; Vlokh, R. [Institute of Physical Optics, Lviv (Ukraine)

    2011-01-15

    We develop and describe analytically a torsion method for measuring piezooptic coefficients associated with shear stresses. It is shown that the method enables to increase significantly the accuracy of determination of piezooptic coefficients. The method and the appropriate apparatus are verified experimentally on the example of LiNbO{sub 3} crystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Thermal Expansion Coefficients of Thin Crystal Films

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The formulas for atomic displacements and Hamiltonian of a thin crystal film in phonon occupation number representation are obtained with the aid of Green's function theory. On the basis of these results, the formulas for thermal expansion coefficients of the thin crystal film are derived with the perturbation theory, and the numerical calculations are carried out. The results show that the thinner films have larger thermal expansion coefficients.

  3. Photon diffusion coefficient in an absorbing medium

    OpenAIRE

    Aronson, Raphael; Corngold, Noel

    1999-01-01

    A number of investigators have recently claimed, based on both analysis from transport theory and transport theory-based Monte Carlo calculations, that the diffusion coefficient for photon migration should be taken to be independent of absorption. We show that these analyses are flawed and that the correct way of extracting diffusion theory from transport theory gives an absorption-dependent diffusion coefficient. Experiments by two different sets of investigators give conflicting results con...

  4. Mass transfer coefficients in metallurgical reactors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An overview on the application and achievements of physico-mathematical modeling of metallurgical processes in Chinais briefly declared. The important role of coefficients in model formulation is shown from our experience. The mass transfer coeffi-cients of the slag-metal reactions and the gas-metal reactions are discussed referring to the flow conditions near the interface. Theinfluence of the surface-active species on the mass transfer and the inteffacial reaction is also discussed briefly.

  5. Clustering coefficient without degree correlations biases

    OpenAIRE

    Soffer, Sara Nadiv; Vazquez, Alexei

    2004-01-01

    The clustering coefficient quantifies how well connected are the neighbors of a vertex in a graph. In real networks it decreases with the vertex degree, which has been taken as a signature of the network hierarchical structure. Here we show that this signature of hierarchical structure is a consequence of degree correlation biases in the clustering coefficient definition. We introduce a new definition in which the degree correlation biases are filtered out, and provide evidence that in real n...

  6. Transport coefficients for inelastic Maxwell mixtures

    OpenAIRE

    Garzo, Vicente; Astillero, Antonio

    2004-01-01

    The Boltzmann equation for inelastic Maxwell models is used to determine the Navier-Stokes transport coefficients of a granular binary mixture in $d$ dimensions. The Chapman-Enskog method is applied to solve the Boltzmann equation for states near the (local) homogeneous cooling state. The mass, heat, and momentum fluxes are obtained to first order in the spatial gradients of the hydrodynamic fields, and the corresponding transport coefficients are identified. There are seven relevant transpor...

  7. Thermal expansion coefficient of binary semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Sastry, B.S.R. [Indian School of Mines, Dhanbad (India). Dept. of Electronics and Instrumentation

    2001-07-01

    The linear thermal expansion coefficient of tetrahedrally coordinated A{sup II}B{sup VI} and A{sup III}B{sup V} semiconductors has been calculated using plasmon energy data. A simple relation between the bond length and plasmon energy has been derived. The calculated values of thermal expansion coefficient and bond length have been compared with the experimental values and the values reported by different workers. An excellent experiment has been obtained between them. (orig.)

  8. On computing Laplace's coefficients and their derivatives.

    Science.gov (United States)

    Gerasimov, I. A.; Vinnikov, E. L.

    The algorithm of computing Laplace's coefficients and their derivatives is proposed with application of recurrent relations. The A.G.M.-method is used for the calculation of values L0(0), L0(1). The FORTRAN-program corresponding to the algorithm is given. The precision control was provided with numerical integrating by Simpsons method. The behavior of Laplace's coefficients and their third derivatives whith varying indices K, n for fixed values of the α-parameter is presented graphically.

  9. Fractal fractal dimensions of deterministic transport coefficients

    OpenAIRE

    Klages, R.; Klauss, T.

    2003-01-01

    If a point particle moves chaotically through a periodic array of scatterers the associated transport coefficients are typically irregular functions under variation of control parameters. For a piecewise linear two-parameter map we analyze the structure of the associated irregular diffusion coefficient and current by numerically computing dimensions from box-counting and from the autocorrelation function of these graphs. We find that both dimensions are fractal for large parameter intervals a...

  10. Decomposition of the Gini coefficient using Stata

    OpenAIRE

    Alejandro López Feldman

    2009-01-01

    The Gini coefficient is widely used to measure inequality in the distribution of income, consumption, and other welfare proxies. Decomposing this measure can help you understand the determinants of inequality. In this presentation, I will use income data from Mexico to illustrate a user-written command, descogini, that implements the Gini decomposition proposed by Lerman and Yitzhaki (1985, Review of Economics and Statistics 67: 151–156). Using this command, the Gini coefficient for total inc...

  11. Measuring Resource Inequality: The Gini Coefficient

    Directory of Open Access Journals (Sweden)

    Michael T. Catalano

    2009-07-01

    Full Text Available This paper stems from work done by the authors at the Mathematics for Social Justice Workshop held in June of 2007 at Middlebury College. We provide a description of the Gini coefficient and some discussion of how it can be used to promote quantitative literacy skills in mathematics courses. The Gini Coefficient was introduced in 1921 by Italian statistician Corrado Gini as a measure of inequality. It is defined as twice the area between two curves. One, the Lorenz curve for a given population with respect to a given resource, represents the cumulative percentage of the resource as a function of the cumulative percentage of the population that shares that percentage of the resource. The second curve is the line y = x which is the Lorenz curve for a population which shares the resource equally. The Gini coefficient can be interpreted as the percentage of inequality represented in the population with respect to the given resource. We propose that the Gini coefficient can be used to enhance students’ understanding of calculus concepts and provide practice for students in using both calculus and quantitative literacy skills. Our examples are based mainly on distribution of energy resources using publicly available data from the Energy Information Agency of the United States Government. For energy resources within the United States, we find that by household, the Gini coefficient is 0.346, while using the 51 data points represented by the states and Washington D.C., the Gini coefficient is 0.158. When we consider the countries of the world as a population of 210, the Gini coefficient is 0.670. We close with ideas for questions which can be posed to students and discussion of the experiences two other mathematics instructors have had incorporating the Gini coefficient into pre-calculus-level mathematics classes.

  12. Experimental Mg IX photo recombination rate coefficient

    International Nuclear Information System (INIS)

    The rate coefficient for radiative and dielectronic recombination of beryllium-like magnesium ions was measured with high resolution at the Heidelberg heavy-ion storage ring TSR. In the electron-ion collision energy range 0-207 eV resonances due to 2s → 2p (ΔN = 0) and 2s → 3l (ΔN = 1) core excitations were detected. At low energies below 0.15 eV the recombination rate coefficient is dominated by strong 1s2(2s2p 3P)7l resonances with the strongest one occurring at an energy of only 21 meV. These resonances decisively influence the Mg IX recombination rate coefficient in a low temperature plasma. The experimentally derived Mg IX dielectronic recombination rate coefficient (±15% systematical uncertainty) is compared with the recommendation by Mazzotta et al. (1998, AandAS, 133, 403) and the recent calculations by Gu (2003, ApJ, 590, 1131) and by Colgan et al. (2003, AandA, 412, 597). These results deviate from the experimental rate coefficient by 130%, 82% and 25%, respectively, at the temperature where the fractional abundance of Mg IX is expected to peak in a photoionized plasma. At this temperature a theoretical uncertainty in the 1s2(2s2p 3P)7l resonance positions of only 100 meV would translate into an uncertainty of the plasma rate coefficient of almost a factor 3. This finding emphasizes that an accurate theoretical calculation of the Mg IX recombination rate coefficient from first principles is challenging. (authors)

  13. Experimental Mg IX photorecombination rate coefficient

    Science.gov (United States)

    Schippers, S.; Schnell, M.; Brandau, C.; Kieslich, S.; Müller, A.; Wolf, A.

    2004-07-01

    The rate coefficient for radiative and dielectronic recombination of beryllium-like magnesium ions was measured with high resolution at the Heidelberg heavy-ion storage ring TSR. In the electron-ion collision energy range 0-207 eV resonances due to 2s -> 2p (Δ N = 0) and 2s -> 3l (Δ N=1) core excitations were detected. At low energies below 0.15 eV the recombination rate coefficient is dominated by strong 1s2 (2s 2p 3P) 7l resonances with the strongest one occuring at an energy of only 21 meV. These resonances decisively influence the Mg IX recombination rate coefficient in a low temperature plasma. The experimentally derived Mg IX dielectronic recombination rate coefficient (±15% systematical uncertainty) is compared with the recommendation by Mazzotta et al. (1998, A&AS, 133, 403) and the recent calculations by Gu (2003, ApJ, 590, 1131) and by Colgan et al. (2003, A&A, 412, 597). These results deviate from the experimental rate coefficient by 130%, 82% and 25%, respectively, at the temperature where the fractional abundance of Mg IX is expected to peak in a photoionized plasma. At this temperature a theoretical uncertainty in the 1s2 (2s 2p 3P) 7l resonance positions of only 100 meV would translate into an uncertainty of the plasma rate coefficient of almost a factor 3. This finding emphasizes that an accurate theoretical calculation of the Mg IX recombination rate coefficient from first principles is challenging.

  14. Experimental methodology for obtaining sound absorption coefficients

    Directory of Open Access Journals (Sweden)

    Carlos A. Macía M

    2011-07-01

    Full Text Available Objective: the authors propose a new methodology for estimating sound absorption coefficients using genetic algorithms. Methodology: sound waves are generated and conducted along a rectangular silencer. The waves are then attenuated by the absorbing material covering the silencer’s walls. The attenuated sound pressure level is used in a genetic algorithm-based search to find the parameters of the proposed attenuation expressions that include geometric factors, the wavelength and the absorption coefficient. Results: a variety of adjusted mathematical models were found that make it possible to estimate the absorption coefficients based on the characteristics of a rectangular silencer used for measuring the attenuation of the noise that passes through it. Conclusions: this methodology makes it possible to obtain the absorption coefficients of new materials in a cheap and simple manner. Although these coefficients might be slightly different from those obtained through other methodologies, they provide solutions within the engineering accuracy ranges that are used for designing noise control systems.

  15. Experimental Mg IX photorecombination rate coefficient

    CERN Document Server

    Schippers, S; Brandau, C; Kieslich, S; Müller, A; Wolf, A

    2004-01-01

    The rate coefficient for radiative and dielectronic recombination of berylliumlike magnesium ions was measured with high resolution at the Heidelberg heavy-ion storage ring TSR. In the electron-ion collision energy range 0-207 eV resonances due to 2s -> 2p (Delta N = 0) and 2s -> 3l (Delta N=1) core excitations were detected. At low energies below 0.15 eV the recombination rate coefficient is dominated by strong 1s2 (2s 2p 3P) 7l resonances with the strongest one occuring at an energy of only 21 meV. These resonances decisively influence the Mg IX recombination rate coefficient in a low temperature plasma. The experimentally derived Mg IX dielectronic recombination rate coefficient (+-15% systematical uncertainty) is compared with the recommendation by Mazzotta et al. (1998, A&AS, 133, 403) and the recent calculations by Gu (2003, ApJ, 590, 1131) and by Colgan et al. (2003, A&A, 412, 597). These results deviate from the experimental rate coefficient by 130%, 82% and 25%, respectively, at the temperatu...

  16. Effect of Rare Earths on Diffusion Coefficient and Transfer Coefficient of Carbon during Carburizing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The diffusion coefficient of carbon in surface layer of steel-20 rare earth carburized at 880 ℃ and 900 ℃ for 8 h was calculated by substituting the measured layer depths into the diffusion equation. The mathematical model of the transfer coefficient of carbon was deduced based on the kinetics of weight gain during gas carburizing. The calculated results show that the main reason why the gas carburizing process is accelerated is due to the obvious increase in the diffusion coefficient and transfer coefficient of carbon resulted from the addition of RE.

  17. Improved Diffusion Coefficients for Stellar Plasmas

    Science.gov (United States)

    Brassard, P.; Fontaine, G.

    2014-04-01

    We are currently working on the fourth generation of our codes for building evolutionary and static models of hot subdwarf and white dwarf stars. One of the improvements of these codes consists in an update of all the microphysics involved in the computations. As part of our efforts, we have taken a look at possible improvements for the diffusion coefficients. Since the publication of the widely used diffusion coefficients of Paquette et al. (1986), the number-crunching power of computers has immensely increased, allowing more accurate computations of the triple collision integrals. We have thus produced new tables of diffusion coefficients with higher accuracy and higher resolution than before, of general use in stellar astrophysics.

  18. Estimating Runoff Coefficients Using Weather Radars

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.;

    2012-01-01

    of separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678ha) located in the municipality of Aarhus, Denmark. The study has proven it is possible to use corresponding measurements of the relative rainfall distribution over the catchment and runoff...... measurements to identify the runoff coefficients at subcatchment level. The number of potential subcatchments is limited by the number of available rainfall events with a sufficient spatial variability.......This paper presents a method for estimating runoff coefficients of urban drainage catchments based on a combination of high resolution weather radar data and insewer flow measurements. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients...

  19. Estimating inbreeding coefficients from NGS data

    DEFF Research Database (Denmark)

    Vieira, Filipe Garrett; Fumagalli, Matteo; Albrechtsen, Anders;

    2013-01-01

    Most methods for Next-Generation Sequencing (NGS) data analyses incorporate information regarding allele frequencies using the assumption of Hardy-Weinberg Equilibrium (HWE) as a prior. However, many organisms including domesticated, partially selfing or with asexual life cycles show strong...... deviations from HWE. For such species, and specially for low coverage data, it is necessary to obtain estimates of inbreeding coefficients (F) for each individual beforecalling genotypes. Here, we present two methods for estimating inbreeding coefficients from NGS data based on an Expectation...

  20. Factorization of Transport Coefficients in Macroporous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2000-01-01

    We prove the fundamental theorem about factorization of the phenomenological coefficients for transport in macroporous media. By factorization we mean the representation of the transport coefficients as products of geometric parameters of the porous medium and the parameters characteristic...... of the multicomponent fluid saturating the porous space. The two permeabilities of the porous medium, the convective and the diffusional ones, are separated. A similarity between the diffusional permeability and the porosity-tortuosity factor of the Kozeny-Carman theory is demonstrated. We do not make any specific...

  1. Coefficient of Restitution of Wet Tennis Balls

    OpenAIRE

    Eugene Jang; Tony Kim

    2014-01-01

    The coefficient of restitution of a damp tennis ball is of interest to tennis players. Using a spray bottle, water was added to a tennis ball and the mass of water on the wet ball was determined. The ball was then dropped from a fixed height of 0.86 m. The motion was recorded with a video camera and the bounce height was measured. Using the bounce height and the original height, the coefficient of restitution for that mass of added water was determined. The research found the mass of wa...

  2. Study on the Friction Coefficient in Grinding

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The friction between the abrasive grains and workpi ec e is a crutial factor determining the main grinding output. Few studies have bee n carried out investigating the values of the friction coefficient in grinding, due to the difficulty of direct measurement. In this paper, a mathematical model of the friction coefficient in grinding has been established with the aid of a new grinding parameter C ge, which has close relations to wheel wear rate Z s, metal removal rate Z w, specific energy u and gr...

  3. Control in the coefficients with variational crimes

    DEFF Research Database (Denmark)

    Evgrafov, Anton; Marhadi, Kun Saptohartyadi

    2012-01-01

    We study convergence of discontinuous Galerkin-type discretizations of the problems of control in the coefficients of uniformly elliptic partial differential equations (PDEs). As a model problem we use that of the optimal design of thin (Kirchhoff) plates, where the governing equations are of the......We study convergence of discontinuous Galerkin-type discretizations of the problems of control in the coefficients of uniformly elliptic partial differential equations (PDEs). As a model problem we use that of the optimal design of thin (Kirchhoff) plates, where the governing equations...

  4. Viscous Coefficients of a Hot Pion Gas

    Directory of Open Access Journals (Sweden)

    Sourav Sarkar

    2013-01-01

    Full Text Available The steps essentially involved in the evaluation of transport coefficients in linear response theory using Kubo formulas are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we evaluate the viscosities of a pion gas carrying out both the steps in the real-time formulation. We also obtain the viscous coefficients by solving the relativistic transport equation in the Chapman-Enskog approximation to leading order. An in-medium π π cross-section is used in which spectral modifications are introduced in the propagator of the exchanged ρ .

  5. Shear viscosity coefficient of liquid lanthanides

    International Nuclear Information System (INIS)

    Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides

  6. Asymptotics of loop quantum gravity fusion coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Alesci, Emanuele; Bianchi, Eugenio; Magliaro, Elena; Perini, Claudio, E-mail: alesci@fis.uniroma3.i, E-mail: e.bianchi@sns.i, E-mail: elena.magliaro@gmail.co, E-mail: claude.perin@libero.i [Centre de Physique Theorique de Luminy , case 907, F-13288 Marseille (France)

    2010-05-07

    The fusion coefficients from SO(3) to SO(4) play a key role in the definition of spin foam models for the dynamics in loop quantum gravity. In this paper we give a simple analytic formula of the Engle-Pereira-Rovelli-Livine fusion coefficients. We study the large spin asymptotics and show that they map SO(3) semiclassical intertwiners into SU(2){sub L} x SU(2){sub R} semiclassical intertwiners. This non-trivial property opens the possibility for an analysis of the semiclassical behavior of the model.

  7. Fokker-Planck Type Equations with Sobolev Diffusion Coefficients and BV Drift Coefficients

    Institute of Scientific and Technical Information of China (English)

    De Jun LUO

    2013-01-01

    Combining Le Bris and Lions' arguments with Ambrosio's commutator estimate for BV vector fields,we prove in this paper the existence and uniqueness of solutions to the Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients.

  8. Extending the Constant Coefficient Solution Technique to Variable Coefficient Ordinary Differential Equations

    Science.gov (United States)

    Mohammed, Ahmed; Zeleke, Aklilu

    2015-01-01

    We introduce a class of second-order ordinary differential equations (ODEs) with variable coefficients whose closed-form solutions can be obtained by the same method used to solve ODEs with constant coefficients. General solutions for the homogeneous case are discussed.

  9. IS THE SAMPLE COEFFICIENT OF VARIATION A GOOD ESTIMATOR FOR THE POPULATION COEFFICIENT OF VARIATION?

    OpenAIRE

    Mahmoudvand, Rahim; Hassani, Hossein; Wilson, Rob

    2007-01-01

    In this paper, we obtain bounds for the population coefficient of variation (CV) in Bernoulli, Discrete Uniform, Normal and Exponential distributions. We also show that the sample coefficient of variation (cv) is not an accurate estimator of the population CV in the above indicated distributions. Finally we provide some suggestions based on the Maximum Likelihood Estimation to improve the population CV estimate.

  10. Pressure-viscosity coefficient of biobased lubricants

    Science.gov (United States)

    Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...

  11. Infinite matrices, wavelet coefficients and frames

    Directory of Open Access Journals (Sweden)

    N. A. Sheikh

    2004-01-01

    Full Text Available We study the action of A on f∈L2(ℝ and on its wavelet coefficients, where A=(almjklmjk is a double infinite matrix. We find the frame condition for A-transform of f∈L2(ℝ whose wavelet series expansion is known.

  12. Regularity of the Interband Light Absorption Coefficient

    Indian Academy of Sciences (India)

    M Krishna

    2010-06-01

    In this paper we consider the interband light absorption coefficient (ILAC), in a symmetric form, in the case of random operators on the -dimensional lattice. We show that the symmetrized version of ILAC is either continuous or has a component which has the same modulus of continuity as the density of states.

  13. Confidence Intervals for Cronbach's Coefficient Alpha Values

    NARCIS (Netherlands)

    A.J. Koning (Alex); Ph.H.B.F. Franses (Philip Hans)

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, wh

  14. Detailed Investigations of Load Coefficients on Grates

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Rasmussen, Michael R.; Frigaard, Peter

    In this report is presented the results of model tests carried out at Dept. of Civil Engineering, aalborg University (AAU) on behalf of DONG Energy A/S and Vattenfall A/S, Denmark. The objective of the tests was to investigate the load coefficient on different grates and a solid plate for designing...

  15. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  16. Coefficient of Restitution of a Tennis Ball

    OpenAIRE

    Andre Roux; Jennifer Dickerson

    2007-01-01

    The coefficient of restitution (COR) of a tennis ball was investigated over a range of impact velocities. It was found that the COR of the ball was lower than ATP regulations specify, and that the COR decreased with increasing impact velocity.

  17. Coupling coefficients for coupled-cavity lasers

    Energy Technology Data Exchange (ETDEWEB)

    Lang, R.J.; Yariv, A.

    1987-03-01

    The authors derive simple, analytic formulas for the field coupling coefficients in a two-section coupled-cavity laser using a local field rate equation treatment. They show that there is a correction to the heuristic formulas based on power flow calculated by Marcuse; the correction is in agreement with numerical calculations from a coupled-mode approach.

  18. Probability based calibration of pressure coefficients

    DEFF Research Database (Denmark)

    Hansen, Svend Ole; Pedersen, Marie Louise; Sørensen, John Dalsgaard

    2015-01-01

    not depend on the type of variable action. A probability based calibration of pressure coefficients have been carried out using pressure measurements on the standard CAARC building modelled on scale of 1:383. The extreme pressures measured on the CAARC building model in the wind tunnel have been fitted...

  19. Experimental determination of bagasse stiffness coefficient

    Directory of Open Access Journals (Sweden)

    Nelson Arzola de la Peña

    2010-04-01

    Full Text Available The experimentally determined stiffness coefficient of bagasse is described in this paper. This property defines the behaviour of the reaction forces exerted upon the bagasse layer when being compressed during juice-extraction in a sugar-cane mill. This information is important for correctly analysing sugar-cane mill operation and design. An experimental device was used for obtaining the stiffness coefficient; it consisted of a piston, a piston-skirt, a hydraulic press and instrumentation for measuring the pressures so produced and piston position at different times. Compression rate, humidity level and degree of bagasse fragmentation were the experimental factors taken into account in the experimental design. The investigation was carried out with 40%-80% humidity level and up to 0.06 compression rates. All experimental factors proved statistically significant in the bagasse stiffness coefficient experimental model so obtained. Bagasse was seen to behave as a very rigid elastic material under normal sugar-mill pressure operating conditions, having 50 MPa to 20,000 MPa stiffness coefficient values.

  20. Wind speed scaling and the drag coefficient

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Wind speed scaling in similarity law in wind-generated waves and the drag coefficient are studied. In analyzing the data in the wind wave channel, it is found that the u. scaling greatly reduces the scatter in the U10 scaling. The u. scaling has much less scatter than the scaling using other wind speeds. The friction velocity seems to play a distinctive role in wave growth. The result is important in the applications of the similarity law and in wave modeling. In theory it gives an insight into the mechanism of wind wave interaction. It is found that wave steepness is important in influencing the drag coefficient. The variability of the coefficients in the currently widely used drag form can be explained by the differences in wave steepness in the observations. A drag coefficient model with wind speed and wave steepness as parameters is proposed. An explanation for Kahma' s result that the u. scaling does not reduce the scatter in the U10 scaling is given.

  1. The Evolution of Pearson's Correlation Coefficient

    Science.gov (United States)

    Kader, Gary D.; Franklin, Christine A.

    2008-01-01

    This article describes an activity for developing the notion of association between two quantitative variables. By exploring a collection of scatter plots, the authors propose a nonstandard "intuitive" measure of association; and by examining properties of this measure, they develop the more standard measure, Pearson's Correlation Coefficient. The…

  2. Bitplane Image Coding With Parallel Coefficient Processing.

    Science.gov (United States)

    Auli-Llinas, Francesc; Enfedaque, Pablo; Moure, Juan C; Sanchez, Victor

    2016-01-01

    Image coding systems have been traditionally tailored for multiple instruction, multiple data (MIMD) computing. In general, they partition the (transformed) image in codeblocks that can be coded in the cores of MIMD-based processors. Each core executes a sequential flow of instructions to process the coefficients in the codeblock, independently and asynchronously from the others cores. Bitplane coding is a common strategy to code such data. Most of its mechanisms require sequential processing of the coefficients. The last years have seen the upraising of processing accelerators with enhanced computational performance and power efficiency whose architecture is mainly based on the single instruction, multiple data (SIMD) principle. SIMD computing refers to the execution of the same instruction to multiple data in a lockstep synchronous way. Unfortunately, current bitplane coding strategies cannot fully profit from such processors due to inherently sequential coding task. This paper presents bitplane image coding with parallel coefficient (BPC-PaCo) processing, a coding method that can process many coefficients within a codeblock in parallel and synchronously. To this end, the scanning order, the context formation, the probability model, and the arithmetic coder of the coding engine have been re-formulated. The experimental results suggest that the penalization in coding performance of BPC-PaCo with respect to the traditional strategies is almost negligible.

  3. Coefficient of Restitution of a Tennis Ball

    Directory of Open Access Journals (Sweden)

    Andre Roux

    2007-06-01

    Full Text Available The coefficient of restitution (COR of a tennis ball was investigated over a range of impact velocities. It was found that the COR of the ball was lower than ATP regulations specify, and that the COR decreased with increasing impact velocity.

  4. Recursive Construction of Operator Product Expansion Coefficients

    Science.gov (United States)

    Holland, Jan; Hollands, Stefan

    2015-06-01

    We derive a novel formula for the derivative of operator product expansion (OPE) coefficients with respect to a coupling constant. The formula involves just the OPE coefficients themselves but no further input, and is in this sense self-consistent. Furthermore, unlike other formal identities of this general nature in quantum field theory (such as the formal expression for the Lagrangian perturbation of a correlation function), our formula requires no further UV-renormalization, i.e., it is completely well-defined from the start. This feature is a result of a cancelation of UV- and IR-divergences between various terms in our identity. Our proof, and an analysis of the features of the identity, is given for the example of massive, Euclidean theory in 4 dimensional Euclidean space. It relies on the renormalization group flow equation method and is valid to arbitrary, but finite orders in perturbation theory. The final formula, however, makes neither explicit reference to the renormalization group flow, nor to perturbation theory, and we conjecture that it also holds non-perturbatively. Our identity can be applied constructively because it gives a novel recursive algorithm for the computation of OPE coefficients to arbitrary (finite) perturbation order in terms of the zeroth order coefficients corresponding to the underlying free field theory, which in turn are trivial to obtain. We briefly illustrate the relation of this method to more standard methods for computing the OPE in some simple examples.

  5. Second virial coefficients of dipolar hard spheres

    NARCIS (Netherlands)

    Philipse, A.P.; Kuipers, B.W.M.

    2010-01-01

    An asymptotic formula is reported for the second virial coefficient B2 of a dipolar hard-sphere (DHS) fluid, in zero external field, for strongly coupled dipolar interactions. This simple formula, together with the one for the weak-coupling B2, provides an accurate prediction of the second virial co

  6. Coefficient of variation of underwater irradiance fluctuations

    Science.gov (United States)

    Weber, V. L.

    2010-06-01

    We consider underwater sunlight fluctuations in the case of a one-dimensional irregular sea surface. Several rigorous and approximate models are proposed, which make it possible to analytically treat and physically explain the dependence of the coefficient of variation of the underwater irradiance on the depth, the wind velocity, and optical parameters of the sea water.

  7. Coefficient convexity of divisors of x^n-1

    CERN Document Server

    Decker, Andreas

    2010-01-01

    We say a polynomial f having integer coefficients is strongly coefficient convex if the set of coefficients of f consists of consecutive integers only. We establish various results suggesting that the divisors of x^n-1 with integer coefficients have the tendency to be strongly coefficient convex and have small coefficients. The case where n=p^2*q with p and q primes is studied in detail.

  8. Series extension: predicting approximate series coefficients from a finite number of exact coefficients

    Science.gov (United States)

    Guttmann, Anthony J.

    2016-10-01

    Given the first 20-100 coefficients of a typical generating function of the type that arises in many problems of statistical mechanics or enumerative combinatorics, we show that the method of differential approximants performs surprisingly well in predicting (approximately) subsequent coefficients. These can then be used by the ratio method to obtain improved estimates of critical parameters. In favourable cases, given only the first 20 coefficients, the next 100 coefficients are predicted with useful accuracy. More surprisingly, this is also the case when the method of differential approximants does not do a useful job in estimating the critical parameters, such as those cases in which one has stretched exponential asymptotic behaviour. Nevertheless, the coefficients are predicted with surprising accuracy. As one consequence, significant computer time can be saved in enumeration problems where several runs would normally be made, modulo different primes, and the coefficients constructed from their values modulo different primes. Another is in the checking of newly calculated coefficients. We believe that this concept of approximate series extension opens up a whole new chapter in the method of series analysis.

  9. An assessment of coefficient accuracy in linear regression models with spatially varying coefficients

    Science.gov (United States)

    Wheeler, David C.; Calder, Catherine A.

    2007-06-01

    The realization in the statistical and geographical sciences that a relationship between an explanatory variable and a response variable in a linear regression model is not always constant across a study area has led to the development of regression models that allow for spatially varying coefficients. Two competing models of this type are geographically weighted regression (GWR) and Bayesian regression models with spatially varying coefficient processes (SVCP). In the application of these spatially varying coefficient models, marginal inference on the regression coefficient spatial processes is typically of primary interest. In light of this fact, there is a need to assess the validity of such marginal inferences, since these inferences may be misleading in the presence of explanatory variable collinearity. In this paper, we present the results of a simulation study designed to evaluate the sensitivity of the spatially varying coefficients in the competing models to various levels of collinearity. The simulation study results show that the Bayesian regression model produces more accurate inferences on the regression coefficients than does GWR. In addition, the Bayesian regression model is overall fairly robust in terms of marginal coefficient inference to moderate levels of collinearity, and degrades less substantially than GWR with strong collinearity.

  10. Rotational dissipation and the Miesowicz coefficients.

    Science.gov (United States)

    Simões, M; Yamaguti, K; Palangana, A J

    2009-12-01

    In this work, we will study the relative contribution of each of the two dissipative channels of the Eriksen, Leslie, and Parodi (ELP) approach to the observed values of the Miesowicz viscosity coefficients of the nematic liquid crystals. According to the fundamental equation of the liquid crystal's viscosity dissipative process, TS=-integral d3r(sigma)ijA(ij)+hxN , there are two channels by which the nematic viscous dissipation can occur: or it occurs by means of a shear flow configuration, where A(ij) is the characterizing term, or it occurs by means of a rotational configuration, where N is the characterizing term (these parameters will be defined in the paper). It will be also shown that this relative contribution can be measured by a simple relationship connecting the Miesowicz coefficients, which exhibits a quasitemperature independent behavior, suggesting that it is nearly constant through the entire domain of the nematic phase. PMID:20365179

  11. Homomorphic Hashing for Sparse Coefficient Extraction

    CERN Document Server

    Kaski, Petteri; Nederlof, Jesper

    2012-01-01

    We study classes of Dynamic Programming (DP) algorithms which, due to their algebraic definitions, are closely related to coefficient extraction methods. DP algorithms can easily be modified to exploit sparseness in the DP table through memorization. Coefficient extraction techniques on the other hand are both space-efficient and parallelisable, but no tools have been available to exploit sparseness. We investigate the systematic use of homomorphic hash functions to combine the best of these methods and obtain improved space-efficient algorithms for problems including LINEAR SAT, SET PARTITION, and SUBSET SUM. Our algorithms run in time proportional to the number of nonzero entries of the last segment of the DP table, which presents a strict improvement over sparse DP. The last property also gives an improved algorithm for CNF SAT with sparse projections.

  12. Minior Actinide Doppler Coefficient Measurement Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Nolan E. Hertel; Dwayne Blaylock

    2008-04-10

    The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

  13. Meromorphic univalent function with negative coefficient

    Directory of Open Access Journals (Sweden)

    A. Dernek

    1994-01-01

    Full Text Available Let Mn be the classes of regular functions f(z=z−1+a0+a1z+… defined in the annulus 00, (n∈ℕ0, where I0f(z=f(z, If(z=(z−1−z(z−1−2∗f(z, Inf(z=I(In−1f(z, and ∗ is the Hadamard convolution. We denote by Γn=Mn⋃Γ, where Γ denotes the class of functions of the form f(z=z−1+∑k=1∞|ak|zk. We obtained that relates the modulus of the coefficients to starlikeness for the classes Mn and Γn, and coefficient inequalities for the classes Γn.

  14. Hadronic Transport Coefficients from Effective Field Theories

    CERN Document Server

    Torres-Rincon, Juan M

    2012-01-01

    This dissertation focuses on the calculation of transport coefficients in the matter created in a relativistic heavy-ion collision after the chemical freeze-out. This matter can be well approximated by a pion gas out of equilibrium. We describe the theoretical framework to obtain the shear and bulk viscosities, the thermal and electrical conductivities and the flavor diffusion coefficients of a meson gas at low temperatures. To describe the interactions of the degrees of freedom, we use effective field theories with chiral and heavy quark symmetries. We introduce the unitarization methods in order to obtain a scattering amplitude that satisfies the unitarity condition exactly. We perform the calculation of the transport properties of the low temperature phase of quantum chromodynamics -the hadronic medium- that can be used in the hydrodynamic simulations of a relativistic heavy-ion collision and its subsequent evolution. We show that the shear viscosity over entropy density exhibits a minimum in a phase trans...

  15. Transport Coefficients and nPI Methods

    CERN Document Server

    Carrington, M E

    2011-01-01

    Transport coefficients can be obtained from 2-point correlators using the Kubo formulae. It has been shown that the full leading order result for electrical conductivity and (QCD) shear viscosity is contained in the re-summed 2-point function that is obtained from the 3-loop 3PI effective action. The theory produces all leading order contributions without the necessity for power counting, and in this sense it provides a natural framework for the calculation and suggests that one can calculate the next-to-leading contribution to transport coefficients from the 4-loop 4PI effective action. The integral equations have been derived for shear viscosity for a scalar theory with cubic and quartic interactions, with a non-vanishing field expectation value. We review these results, and explain how the calculation could be done at higher orders.

  16. Modification of Slenderness Coefficient of Angle Steels

    Institute of Scientific and Technical Information of China (English)

    刘红燕; 李志业

    2004-01-01

    To provide information for amendment to Technical Specifications for Power Transmission Towers (SDGJ94-90), the critical loads of typical compressed angle steels was calculated. The correlation of buckling loads and slenderness of compressed angle steels was obtained with regression. A new slenderness coefficient equation was proposed based on the result of the correlation. A practical measure to ensure good result in nonlinear solution using Arch-length method is put forward.

  17. Correlation and prediction of gaseous diffusion coefficients.

    Science.gov (United States)

    Marrero, T. R.; Mason, E. A.

    1973-01-01

    A new correlation method for binary gaseous diffusion coefficients from very low temperatures to 10,000 K is proposed based on an extended principle of corresponding states, and having greater range and accuracy than previous correlations. There are two correlation parameters that are related to other physical quantities and that are predictable in the absence of diffusion measurements. Quantum effects and composition dependence are included, but high-pressure effects are not. The results are directly applicable to multicomponent mixtures.

  18. Testing the correlated random coefficient model

    OpenAIRE

    Heckman, James J.; Schmierer, Daniel; Urzua, Sergio

    2010-01-01

    The recent literature on instrumental variables (IV) features models in which agents sort into treatment status on the basis of gains from treatment as well as on baseline-pretreatment levels. Components of the gains known to the agents and acted on by them may not be known by the observing economist. Such models are called correlated random coefficient models. Sorting on unobserved components of gains complicates the interpretation of what IV estimates. This paper examines testable implicati...

  19. Coefficient inequalities for starlikeness and convexity

    Directory of Open Access Journals (Sweden)

    Ali Rosihan M.

    2013-06-01

    Full Text Available For an analytic function $f(z=z+\\sum_{n=2}^\\infty a_n z^n$ satisfying the inequality $\\sum_{n=2}^\\infty n(n-1|a_n|\\leq \\beta$, sharp bound on $\\beta$ is determined so that $f$ is either starlike or convex of order $\\alpha$. Several other coefficient inequalities related to certain subclasses are also investigated.

  20. The attenuation coefficients in CT: Didactic review

    International Nuclear Information System (INIS)

    The review article refers details about the derivation of the Attenuation coefficient of the CT-Number, the electron density and physical density, the effective atomic number, dual KV scanning, the performance of different scanners, furtheron the CT-numbers of intracranial structures, the attempts of characterization of tissue by CT, measurements of effective atomic number and electron density, distribution and probability of occurance of CT-numbers, and distribution of CT-numbers in space. (AJ)

  1. Efficient estimation of price adjustment coefficients

    OpenAIRE

    Lyhagen, Johan

    1999-01-01

    The price adjustment coefficient model of Amihud and Mendelson (1987) is shown to be suitable for estimation by the Kalman filter. A techique that, under some commonly used conditions, is asymptotically efficient. By Monte Carlo simulations it is shown that both bias and mean squared error are much smaler compared to the estimator proposed by Damodaran and Lim (1991) and Damodaran (1993). A test for the adeqacy of the model is also proposed. Using data from four minor, the nordic countries ex...

  2. On the Central Coefficients of Riordan Matrices

    OpenAIRE

    Barry, Paul

    2013-01-01

    We use the Lagrange-Bürmann inversion theorem to characterize the generating function of the central coefficients of the elements of the Riordan group of matrices. We apply this result to calculate the generating function of the central elements of a number of explicit Riordan arrays, defined by rational expressions, and in two cases we use the generating functions thus found to calculate the Hankel transforms of the central elements, which are themselves expressible as combinatorial polynomi...

  3. Basketball Surfaces and Coefficient of Restitution

    OpenAIRE

    Kristyn Peacock; Faith Pearson

    2015-01-01

    A basketball was released from varying drop heights to simulate the impact speeds of a typical soft, medium, and hard dribble. This was repeated across four different surfaces that students typically play on–exposed aggregate concrete, maple wood flooring, EPI Outdoor Sport flooring, and playground rubber mesh. From the measured drop and bounce heights, the coefficient of restitution(COR)was calculated. It was concluded that only playground rubber mesh had COR’s below the regula...

  4. Heterodiffusion coefficients in alpha-iron

    Energy Technology Data Exchange (ETDEWEB)

    Katsika-Tsigourakou, Vassiliki, E-mail: vkatsik@phys.uoa.g [Department of Solid State Physics, Faculty of Physics, University of Athens, Panepistimiopolis Zografos, 15784 Athens (Greece); Skordas, Efthimios S. [Department of Solid State Physics, Faculty of Physics, University of Athens, Panepistimiopolis Zografos, 15784 Athens (Greece)

    2010-04-01

    The diffusion of tungsten in alpha-iron is important for the application of ferritic-iron alloys to thermal power plants. These data, over a wide temperature range across the Curie temperature, have been recently reported. We show that these diffusion coefficients can be satisfactory reproduced in terms of the bulk elastic and expansivity data by means of a thermodynamical model that interconnects point defects parameters with bulk qualities.

  5. Recursive algorithms, branching coefficients and applications

    CERN Document Server

    Lyakhovsky, Vladimir

    2010-01-01

    Recurrent relations for branching coefficients in affine Lie algebras integrable highest weight modules are studied. The decomposition algorithm based on the injection fan technique is adopted to the situation where the Weyl denominator becomes singular with respect to a reductive subalgebra. We study some modifications of the injection fan technique and demonstrate that it is possible to define the "subtracted fans" that play the role similar to the original ones. Possible applications of subtracted fans in CFT models are considered.

  6. Sensitivity of the Heat Transfer Coefficient Calculation

    OpenAIRE

    Singer, Sasa

    2014-01-01

    The purpose of the Liscic/Petrofer probe is to determine the cooling intensity during liquid quenching in laboratory and workshop environments. The surface heat transfer coefficient is calculated by the one-dimensional finite volume method from the smoothed temperature curve, measured at a near-surface point in the probe. Smoothed reference temperature curves for oil and water, based on measurements made by the probe, are used in a series of numerical experiments to investigate the sensitivit...

  7. Coefficients of symmetric square L-functions

    Institute of Scientific and Technical Information of China (English)

    LAU; Yuk-Kam

    2010-01-01

    Let λsym2f(n) be the n-th coefficient in the Dirichlet series of the symmetric square L-function associated with a holomorphic primitive cusp form f.We prove Ω± results for λsym2f(n) and evaluate the number of positive(resp.,negative) λsym2f(n) in some intervals.

  8. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, Alex; Franses, Philip Hans

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for ...

  9. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, A. J.; Franses, Ph.H.B.F.

    2003-01-01

    Coefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for significant ...

  10. ON DAMPING COEFFICIENT DUE TO PHASE TRANSFORMATION

    Institute of Scientific and Technical Information of China (English)

    Din-YuHSIEH

    2003-01-01

    The damping coefficient of capillary waves due to the evaporation-condensation process at the interface of the two phases of a fluid is evaluated. To highlight the mechanism of the effect of heat and mass transfer across the interface between regions of liquid and vapor, potential flow of incompressible fluids are assumed. Thus other mechanisms of damping are neglected. To fascilitate the analysis, the method of multiple-scale is employed in the analysis, even though the problem is linear.

  11. Uranium GI absorption coefficients for young children

    International Nuclear Information System (INIS)

    Uranium is ubiquitously found in drinking water and food. The absorption fraction (f1) is an important parameter in risk assessment of uranium burdens from ingestion. Although absorption of uranium from the gastrointestinal tract (GI) has been studied extensively in both animals and humans in the past, human data among young children are rare. In a previous study based on measurements of uranium concentration in only 11 bone-ash samples collected by Health Canada, the GI absorption coefficient for uranium ingestion by infants, about 3 months of age were determined. The result was 0.256 which was much higher than the ICRP recommended f1 values of 0.04 for infants and 0.02 for anyone more than 1 year of age. To extend the study, a total of 73 bone-ash samples were selected for children ranging in age from 0 to 7 years. The estimated absorption coefficients were 0.093±0.113 for infants, and 0.050±0.032 for 1 - 7 years of age. This study provides human absorption coefficients of ingested uranium for young children of two age groups. (author)

  12. Dependence of the osmotic coefficients and average ionic activity coefficients on hydrophobic hydration in solutions

    Science.gov (United States)

    Sergievskii, V. V.; Rudakov, A. M.

    2016-08-01

    The model that considers the nonideality of aqueous solutions of electrolytes with allowance for independent contributions of hydration of ions of various types and electrostatic interactions was substantiated using the cluster ion model. The empirical parameters in the model equations were found to be the hydrophilic and hydrophobic hydration numbers of ions in the standard state and the dispersion of their distribution over the stoichiometric coefficients. A mathematically adequate description of the concentration dependences of the osmotic coefficients and average ion activity coefficients of electrolytes was given for several systems. The difference in the rate of the decrease in the hydrophilic and hydrophobic hydration numbers of ions leads to extremum concentration dependences of the osmotic coefficients, which were determined by other authors from isopiestic data for many electrolytes and did not find explanation.

  13. The Phi-coefficient, the Tetrachoric Correlation Coefficient, and the Pearson-Yule Debate

    OpenAIRE

    Ekström, Joakim

    2011-01-01

    Two measures of association for dichotomous variables, the phi-coefficient and the tetrachoric correlation coefficient, are reviewed and differences between the two are discussed in the context of the famous so-called Pearson-Yule debate, that took place in the early 20th century. The two measures of association are given mathematically rigorous definitions, their underlying assumptions are formalized, and some key properties are derived. Furthermore, existence of a continuous bijection betwe...

  14. Tests of Hypotheses Arising in the Correlated Random Coefficient Model

    OpenAIRE

    Heckman, James J.; Schmierer, Daniel

    2010-01-01

    This paper examines the correlated random coefficient model. It extends the analysis of Swamy (1971, 1974), who pioneered the uncorrelated random coefficient model in economics. We develop the properties of the correlated random coefficient model and derive a new representation of the variance of the instrumental variable estimator for that model. We develop tests of the validity of the correlated random coefficient model against the null hypothesis of the uncorrelated random coefficient model.

  15. Measuring correlations between non-stationary series with DCCA coefficient

    OpenAIRE

    Ladislav Kristoufek

    2013-01-01

    In this short report, we investigate the ability of the DCCA coefficient to measure correlation level between non-stationary series. Based on a wide Monte Carlo simulation study, we show that the DCCA coefficient can estimate the correlation coefficient accurately regardless the strength of non-stationarity (measured by the fractional differencing parameter $d$). For a comparison, we also report the results for the standard Pearson's correlation coefficient. The DCCA coefficient dominates the...

  16. Hydrodynamic Coefficients of Ships with Forward Speed in Shallow Waters

    Institute of Scientific and Technical Information of China (English)

    M.HASANADIL; DUANWen-yang; WANGYu

    2004-01-01

    Effects of depth and forward speed on hydrodynamic coefficients of ships are presented in this paper. A modified simple Green function technique was used to calculate 2D coefficients while strip theory was used to calculate 3D coefficients. Numerical results are provided for hydrodynamic coefficients of parabolic hull ship. It is found out that both depth and forward speed have considerable effects on hydrodynamic coefficients of ship.

  17. Experimental rotordynamic coefficient results for honeycomb seals

    Science.gov (United States)

    Elrod, David A.; Childs, Dara W.

    1988-01-01

    Test results (leakage and rotordynamic coefficients) are presented for seven honeycomb-stator smooth-rotor seals. Tests were carried out with air at rotor speeds up to 16,000 cpm and supply pressures up to 8.2 bars. Test results for the seven seals are compared, and the most stable configuration is identified based on the whirl frequency ratio. Results from tests of a smooth-rotor/smooth-stator seal, a teeth-on-stator labyrinth seal, and the most stable honeycomb seal are compared.

  18. Studies of Gaseous Multiplication Coefficient in Isobutane

    Science.gov (United States)

    Lima, Iara B.; Vivaldini, Túlio C.; Gonçalves, Josemary A. C.; Botelho, Suzana; Ridenti, Marco A.; Fonte, Paulo; Mangiarotti, Alessio; Pascholati, Paulo R.; Bueno Tobias, Carmen C.

    2010-05-01

    This work presents the studies of gaseous multiplication coefficient behavior for isobutane, as function of the reduced electric field, by means of signal amplitude analysis. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. In our configuration, the anode is made of a high resistivity (2.1012 Ω.cm) glass, while the cathode is of aluminium. In order to validate the technique and to analyze effects of non-uniformity, results for nitrogen, which has well-established data available in literature, are also presented.

  19. Studies of Gaseous Multiplication Coefficient in Isobutane

    International Nuclear Information System (INIS)

    This work presents the studies of gaseous multiplication coefficient behavior for isobutane, as function of the reduced electric field, by means of signal amplitude analysis. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. In our configuration, the anode is made of a high resistivity (2.1012 Ω.cm) glass, while the cathode is of aluminium. In order to validate the technique and to analyze effects of non-uniformity, results for nitrogen, which has well-established data available in literature, are also presented.

  20. Tracking Time-Varying Coefficient-Functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.;

    1999-01-01

    of recursive least squares with exponential forgetting and local polynomial regression. However, it is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal shich is argument of the coeffieient-functions.The properties of the modified method are sutdied......A conditional parametric ARX-model is an ARX-model in which the parameters re replaced by smooth functions of an, possibly multivariate, externalinput signal. These functions are called coefficient functions is suggested. Essentially, in its most simple form, this method is a combination...

  1. Energy reflection coefficient of backscattered heavy ions

    International Nuclear Information System (INIS)

    An energy-dependent albedo problem, i.e., the energy-dependent leakage spectrum for a half-space of material irradiated by a monoenergetic beam of ions is investigated in this paper. For this purpose the flux decomposition procedure is applied. It is based on separation of the ion flux into terms that are exactly analytically solved and those calculated by the ordinary DPN approximation. Slowing down of particles is described by elastic scattering and various models for dealing with the anisotropy of ion scattering. The ion energy reflection coefficient is computed and compared to the values obtained by the exact and variational methods as well as DPN flux approximation

  2. Determination of the surface drag coefficient

    DEFF Research Database (Denmark)

    Mahrt, L.; Vickers, D.; Sun, J.L.;

    2001-01-01

    speed. This dependence on wind speed cannot be eliminated by adjusting the stability functions. If physical, the decrease of the roughness length with increasing wind speed might be due to the decreasing role of viscous effects and streamlining of the vegetation, although these effects cannot...... be isolated from existing atmospheric data. For weak winds, both the mean flow and the stress vector often meander significantly in response to mesoscale motions. The relationship between meandering of the stress and wind vectors is examined. For weak winds, the drag coefficient can be sensitive to the method...... of calculation, partly due to meandering of the stress vector....

  3. Gauge Invariance of Thermal Transport Coefficients

    Science.gov (United States)

    Ercole, Loris; Marcolongo, Aris; Umari, Paolo; Baroni, Stefano

    2016-10-01

    Thermal transport coefficients are independent of the specific microscopic expression for the energy density and current from which they can be derived through the Green-Kubo formula. We discuss this independence in terms of a kind of gauge invariance resulting from energy conservation and extensivity, and demonstrate it numerically for a Lennard-Jones fluid, where different forms of the microscopic energy density lead to different time correlation functions for the heat flux, all of them, however, resulting in the same value for the thermal conductivity.

  4. Determination of coefficient matrices for ARMA model

    International Nuclear Information System (INIS)

    A new recursive algorithm for determining coefficient matrices of ARMA model from measured data is presented. The Yule-Walker equations for the case of ARMA model are derived from the ARMA innovation equation. The recursive algorithm is based on choosing appropriate form of the operator functions and suitable representation of the (n+1)-th order operator functions according to ones with the lower order. Two cases, when the order of the AR part is equal to one of the MA part, and the optimal case, were considered. (author) 5 refs

  5. Semiclassical OPE coefficients from 3D gravity

    CERN Document Server

    Chang, Chi-Ming

    2016-01-01

    We present a closed form expression for the semiclassical OPE coefficients that are universal for all 2D CFTs with a "weak" light spectrum, by taking the semiclassical limit of the fusion kernel. We match this with a properly regularized and normalized bulk action evaluated on a geometry with three conical defects, analytically continued in the deficit angles beyond the range for which a metric with positive signature exists. The analytically continued geometry has a codimension-one coordinate singularity surrounding the heaviest conical defect. This singularity becomes a horizon after Wick rotating to Lorentzian signature, suggesting a connection between universality and the existence of a horizon.

  6. Basketball Surfaces and Coefficient of Restitution

    Directory of Open Access Journals (Sweden)

    Kristyn Peacock

    2015-01-01

    Full Text Available A basketball was released from varying drop heights to simulate the impact speeds of a typical soft, medium, and hard dribble. This was repeated across four different surfaces that students typically play on–exposed aggregate concrete, maple wood flooring, EPI Outdoor Sport flooring, and playground rubber mesh. From the measured drop and bounce heights, the coefficient of restitution(CORwas calculated. It was concluded that only playground rubber mesh had COR’s below the regulation range, with the other three surfaces having COR’s within regulation.

  7. ON DAMPING COEFFICIENT DUE TO PHASE TRANSFORMATION

    Institute of Scientific and Technical Information of China (English)

    Din-Yu HSIEH

    2003-01-01

    The damping coefficient of capillary waves due to the evaporation-condensation process at the interface of the two phases of a fluid is evaluated.To highlight the mechanism of the effect of heat and mass transfer across the interface between regions of liquid and vapor,potential flow of incompressible fluids are assumed.Thus other mechanisms of damping are neglected.To fascilitate the analysis,the method of multiple-scale is employed in the analysis,even though the problem is linear.

  8. Ionization coefficient measurements in DC microplasmas

    Science.gov (United States)

    Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg; Maric, Dragana; Petrovic, Zoran Lj.

    2012-10-01

    While steady state Townsend discharges may provide data for ionization coefficients those are often not as accurate as those produced in dedicated pulsed current growth experiments. In this paper we show that one may be able to measure ionization coefficients in DC microdischarges that are of excellent quality. Measurements were made for argon and argon/nitrogen mixtures with different gas flow rates. The technique based measuring the spatial profile of emission a Townsend discharge. In spite of having the drift length of only 1 mm, excellent agreement has been found between our new measurements and the data for low-pressure, larger dimension (2-4cm) discharges in argon (Jelenak et al) for the E/N in the range from 300 Td to 4000 Td, where E/N is normalized electrical field strength. Below 300 Td our measured values are larger then those by Jelenak et al. This discrepancy with previous measurements will be discussed. The influence of the gas flow-rate and nitrogen concentration on the radial discharge profile in the Townsend mode will also be presented and discussed. Jelenak et al 1993 Phys. Rev. E 47 3566

  9. Measurements of Xe diffusion coefficient of UN

    International Nuclear Information System (INIS)

    Post irradiation annealing (PIA) tests were performed to obtain the Xe-133 diffusion coefficients of uranium nitride (UN). UN powder was obtained from the mixed powder of UO2 and carbon under the H2-N2 gas mixture. Porous discs (45%TD) of UN were made and used for the specimens for the PIA tests. For comparison purposes, porous discs of UO2 (47%TD) were also made. Each 300mg specimen was irradiated to a burnup of 0.1 MWd/t-U. PIA tests were performed at 1200degC, 1300degC and 1400degC for UN, and 1400degC, 1500degC and 1600degC for UO2, continuously. The oxygen potential during the annealing tests was about 440 ± 20 kJ/mol. The disc specimens of UN and UO2 were found to be cracked or broken in pieces after annealing tests. The xenon diffusion coefficient for the near stoichiometric UN turned out to be about 1,000 times higher than that of UO2 at 1400degC. And, the activation energy of diffusion in UN is about 230 kJ/mol, while that of UO2 measured to be about 393 kJ/mol. (author)

  10. Estimating biokinetic coefficients in the PACT™ system.

    Science.gov (United States)

    Shen, Zhiyao; Arbuckle, Wm Brian

    2016-02-01

    When powdered activated carbon (PAC) is continuously added to the aeration tank of an activated sludge reactor, the modification is called a PACT™ process (for powdered activated carbon treatment). The PAC provides many benefits, but complicates the determination of biological phenomena. Determination of bio-oxidation kinetics in a PACT system is a key to fully understanding enhanced biological mechanisms resulting from PAC addition. A model is developed to account for the main mechanisms involved in the PACT system -- adsorption, air stripping and bio-oxidation. The model enables the investigation of biokinetic information, including possible synergistic effects. Six parallel reactors were used to treat a synthetic waste; three activated sludge and three PACT. The PACT reactors provided significantly reduced effluent TOC (total organic carbon). Biokinetic coefficients were obtained from steady-state data using averaged reactor data and by using all data (22 points for each reactor). As expected, the PACT reactors resulted in a substantial reduction in the effluent concentration of non-biodegradable total organic carbon. The Monod equation's half-saturation coefficient (Ks) was reduced significantly in the PACT reactors, resulting in higher growth rates at lower concentrations. The maximum specific substrate utilization (qm) rate was also reduced about 25% using the averaged data and remained unchanged using all the data. The substrate utilization values are affected by errors in biomass determination and more research is needed to accurately determine biomass. PMID:26613352

  11. Soil mass attenuation coefficient: Analysis and evaluation

    International Nuclear Information System (INIS)

    Highlights: • Experimental mass attenuation coefficient is affected by sample size. • Sample thickness larger than 9 cm presents the best results for 137Cs. • Sample thickness smaller than 5 cm presents the best results for 241Am. - Abstract: The mass attenuation coefficient (μ) is an important parameter to characterize the penetration and interaction of gamma-rays in the soil. Accurate determinations of μ are important to obtain representative values of soil physical properties by gamma-ray attenuation technique. In this study, the effect of collimator size (2–4 mm diameters) and absorber thickness (2–15 cm) on the experimental μ values of water and soils with different textures were investigated for 59.54 keV (241Am) and 661.1 keV (137Cs) gamma-ray sources. Theoretical results were calculated using the program XCOM. Experimental results were compared with theoretical ones showing a good correlation between methods. It was observed that for the 137Cs the best agreements between theoretical and experimental μ were obtained for sample thickness ⩾10 cm while for the 241Am were those obtained for thickness <5 cm for small collimators

  12. Recursive construction of operator product expansion coefficients

    CERN Document Server

    Holland, J

    2014-01-01

    We derive a novel formula for the derivative of operator product expansion (OPE) coefficients with respect to a coupling constant. The formula only involves the OPE coefficients themselves, and no further input, and is in this sense self-consistent. Furthermore, unlike other formal identities of this general nature in quantum field theory (such as the formal expression for the Lagrangian perturbation of a correlation function), our formula is completely well-defined from the start, i.e. requires no further UV-renormalization. This feature is a result of a cancelation of UV-divergences between various terms in our identity. Our proof, and an analysis of the features, of our identity is given for the example of massive, Euclidean $\\varphi^4$ theory in 4 dimensional Euclidean space, and relies heavily on the framework of the renormalization group flow equations. It is valid to arbitrary, but finite orders in perturbation theory. The final formula, however, makes no explicit reference to the renormalization group...

  13. Coefficient adaptive triangulation for strongly anisotropic problems

    Energy Technology Data Exchange (ETDEWEB)

    D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.

    1996-01-01

    Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.

  14. A new coefficient of concordance with applications to biosignal analysis

    Science.gov (United States)

    Xu, Weichao; Chen, Zhaoguo; Liu, Wenqing

    2015-12-01

    In this paper we propose a novel concordance coefficients called Order Statistics Concordance Coefficients based on order statistics and Pearson's Product Moment Correlation Coefficient. For comparison, we also construct other three similar index based on Average Pearson's Product Moment Correlation Coefficient, Kendall's Concordance Coefficients, Average Kendall's tau. We propose Multivariate Normal Model to estimate the correlation coefficient, Linear Model and Nonlinear Model to model the linear and nonlinear association between multichannel signals, And we also apply the concordance coefficients to biosignal analysis developed a new organizational index for quantifying organization of AF. Statistical evidences suggest that (a) Order Statistics Concordance Coefficients have better robust than other three index; (b) capable of distinguishing fibrillatory rhythms from nonfibrillatory rhythms, such as Atiral flutter; (c) can reflect the effectiveness of adenosine, a drug commonly used during electrophysiological procedures; and (d) perform better than other three concordance coefficients.

  15. Effective Electrocardiogram Steganography Based on Coefficient Alignment.

    Science.gov (United States)

    Yang, Ching-Yu; Wang, Wen-Fong

    2016-03-01

    This study presents two types of data hiding methods based on coefficient alignment for electrocardiogram (ECG) signals, namely, lossy and reversible ECG steganographys. The lossy method is divided into high-quality and high-capacity ECG steganography, both of which are capable of hiding confidential patient data in ECG signals. The reversible data hiding method can not only hide secret messages but also completely restore the original ECG signal after bit extraction. Simulations confirmed that the perceived quality generated by the lossy ECG steganography methods was good, while hiding capacity was acceptable. In addition, these methods have a certain degree of robustness, which is rare in conventional ECG stegangraphy schemes. Moreover, the proposed reversible ECG steganography method can not only successfully extract hidden messages but also completely recover the original ECG data.

  16. Coefficient alpha and interculture test selection.

    Science.gov (United States)

    Thurber, Steven; Kishi, Yasuhiro

    2014-04-01

    The internal consistency reliability of a measure can be a focal point in an evaluation of the potential adequacy of an instrument for adaptation to another cultural setting. Cronbach's alpha (α) coefficient is often used as the statistical index for such a determination. However, alpha presumes a tau-equivalent test and may constitute an inaccurate population estimate for multidimensional tests. These notions are expanded and examined with a Japanese version of a questionnaire on nursing attitudes toward suicidal patients, originally constructed in Sweden using the English language. The English measure was reported to have acceptable internal consistency (α) albeit the dimensionality of the questionnaire was not addressed. The Japanese scale was found to lack tau-equivalence. An alternative to alpha, "composite reliability," was computed and found to be below acceptable standards in magnitude and precision. Implications for research application of the Japanese instrument are discussed. PMID:22523134

  17. Condensation heat transfer coefficient versus wettability

    Science.gov (United States)

    Roudgar, M.; De Coninck, J.

    2015-05-01

    In this paper we show how condensation on substrates can induce wetting behavior that is quite different from that of deposited or impinging drops. We describe surfaces with the same wettability in ambient conditions presenting different wetting behavior and growth of droplets in condensation. The experimental results show a rapid spread of droplets and formation of the film on the copper surface, while droplets on SU-8 surface remains on the regular shape while they grow within the time, without coalescence, as observed for Cu. Although the heat conductivity of SU-8 is much lower, due to a difference in wetting behavior, the heat transfer coefficient (h) is higher for dropwise condensation on Cu with a thin layer of SU-8 than filmwise on the bare copper.

  18. Experimental measurement of dispersion coefficients for gases

    Energy Technology Data Exchange (ETDEWEB)

    De Delgado, E. [National University at Comahue (Brazil); Da Franca Correa, A.C. [State Univ. of Campinas (Brazil)

    2001-06-01

    A series of experiments were conducted on dispersion, a phenomenon by which molecules of two miscible fluids diffuse into one another when they come into contact with each other. Both longitudinal and transverse diffusion is a result of forced flow. Longitudinal dispersion occurs in the direction of flow, while transverse dispersion occurs perpendicular to the direction of flow. This study focused on measuring longitudinal dispersion coefficients on natural gas displaced by an inert gas (nitrogen) at very low pressure. The experiments were carried out at two different pressure ranges on unconsolidated porous media at a Gas Plant Laboratory near Neuquen, Argentina. Two different types of porous media were used, a plastic hose and a metallic slim tube. They were each filled twice with both natural and synthetic sand grains. The study provided a better understanding of how gases behave at low pressures. 4 refs., 4 tabs., 5 figs.

  19. Thermal Conductivity Coefficient from Microscopic Models

    CERN Document Server

    Nemakhavhani, T E

    2016-01-01

    Thermal conductivity of hadron matter is studied using a microscopic transport model, which will be used to simulate ultra-relativistic heavy ion collisions at different energy densities, namely the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). The molecular dynamics simulation is performed for a system of light mesons species (pion, rho, kaon) in a box with periodic boundary conditions. The equilibrium state is investigated by studying chemical equilibrium and thermal equilibrium of the system. Particle multiplicity equilibrates with time, and the energy spectra of different light mesons species have the same slopes and common temperatures when thermal equilibrium is reached. Thermal conductivity transport coefficient is calculated from the heat current - current correlations using the Green-Kubo relations.

  20. APRECOT - analysis program for reactivity coefficient tests

    International Nuclear Information System (INIS)

    A computer program has been written which provides a rapid and convenient analysis route for fuel temperature coefficient of reactivity measurements, as carried out at Hinkley Point 'B' Power Station. This replaces the earlier, more tedious, iterative analysis using KINAGRAX. The program has been tested by analysing computer simulations of reactor tests. This has shown that APRECOT introduces errors which are small (approximately 11/2%) in comparison with other sources of error (approximately 10%), that the effect of axial flux shape changes is acceptably small and that effects due to xenon, which is not modelled in the current version of the program, can be dealt with adequately. This note describes the APRECOT method, including details of input and output to the program and gives results of the numerical tests made of the method. (author)

  1. ROUGHNESS COEFFICIENT FOR UNSUBMERGED AND SUBMERGED REED

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The characteristics of the roughness coefficient are very important for practical application. Some experiments are conducted to study the variation of Manning's n with flow depth, mean velocity, and density of vegetation,. An assumed velocity distribution to describe the vegetative flow of submerged vegetation is confirmed by experimental results. The measured velocities in this study seem to have little effect on the curve of n ~ h, and a new linear relationship between Manning's n and flow depths is observed clearly. According to the arguments that the flow resistance of densely unsubmerged vegetation is dominated by the resistance exerted on vegetations, the influence of the density of vegetation on Manning's n is estimated. On the basis of the velocity distribution, the n ~ h curve under submerged condition is theoretically obtained from the n ~ h curve under unsubmerged condition. These results are also well confirmed by experimental results and very significant for practical applications.

  2. Friction Experiments for Dynamical Coefficient Measurement

    Directory of Open Access Journals (Sweden)

    J. J. Arnoux

    2011-01-01

    Full Text Available An experimental study, including three experimental devices, is presented in order to investigate dry friction phenomena in a wide range of sliding speeds for the steel on steel contact. A ballistic setup, with an air gun launch, allows to estimate the friction coefficient between 20 m/s and 80 m/s. Tests are completed by an adaptation of the sensor on a hydraulic tensile machine (0.01 m/s to 3 m/s and a pin-on-disk tribometer mounted on a CNC lathe (1 to 30 m/s. The interactions at the asperity scale are characterized by a white light interferometer surface analysis.

  3. Comment on "Generalized exclusion processes: Transport coefficients"

    Science.gov (United States)

    Becker, T.; Nelissen, K.; Cleuren, B.; Partoens, B.; Van den Broeck, C.

    2016-04-01

    In a recent paper, Arita et al. [Phys. Rev. E 90, 052108 (2014), 10.1103/PhysRevE.90.052108] consider the transport properties of a class of generalized exclusion processes. Analytical expressions for the transport-diffusion coefficient are derived by ignoring correlations. It is claimed that these expressions become exact in the hydrodynamic limit. In this Comment, we point out that (i) the influence of correlations upon the diffusion does not vanish in the hydrodynamic limit, and (ii) the expressions for the self- and transport diffusion derived by Arita et al. are special cases of results derived in Becker et al. [Phys. Rev. Lett. 111, 110601 (2013), 10.1103/PhysRevLett.111.110601].

  4. Distortion effects on the spin transfer coefficient

    CERN Document Server

    Lee, S E; Hong, S W; Kim, B T

    1999-01-01

    We investigated the distortion effects on the spin transfer coefficient D sub n sub n for the intermediate energy (p,n) charge exchange reactions leading to the Gamow-Teller resonance in the continuum region. When the distortion is included, the imaginary parts of both the central and the tensor direct contributions are significantly changed. Also, the magnitude of T sub 0 sub 0 becomes smaller, which results in larger D sub n sub n values. We also found that when the distortion is included the phase difference between T sub 0 sub 0 and T sub 2 sub 0 in the complex plane remains almost the same for different Q-values.

  5. Transport coefficients in superfluid neutron stars

    CERN Document Server

    Tolos, Laura; Sarkar, Sreemoyee; Tarrus, Jaume

    2014-01-01

    We study the shear and bulk viscosity coefficients as well as the thermal conductivity as arising from the collisions among phonons in superfluid neutron stars. We use effective field theory techniques to extract the allowed phonon collisional processes, written as a function of the equation of state and the gap of the system. The shear viscosity due to phonon scattering is compared to calculations of that coming from electron collisions. We also comment on the possible consequences for r-mode damping in superfluid neutron stars. Moreover, we find that phonon collisions give the leading contribution to the bulk viscosities in the core of the neutron stars. We finally obtain a temperature-independent thermal conductivity from phonon collisions and compare it with the electron-muon thermal conductivity in superfluid neutron stars.

  6. Secondary Ionization Coefficient of Dielectric Electrode

    Science.gov (United States)

    Kashiwagi, Yasuhide; Suzuki, Susumu; Itoh, Haruo

    Experiments for observations and stabilization of discharge paths in several electrode systems are carried out aiming at precise measurement of the secondary ionization coefficient γ of MgO film electrode. The discharge chamber is filled with Ar gas. The waveforms of the applied voltage between the electrodes and the discharge current are measured with visual observation of the discharge light. Two MgO coated electrodes are placed so that they are facing each other. For these MgO electrodes, the discharge paths take a detour, not the shortest distance. Smaller prebreakdown current pulses are observed before the breakdown. After breakdown, discontinuous discharge current is observed. Therefore, it is prepared a glass tube surrounding the discharge area. As the result, the discharge paths take a straight perpendicular for the electrode surface, and the discharge is stabilized.

  7. Transport coefficients in superfluid neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Tolos, Laura [Instituto de Ciencias del Espacio (IEEC/CSIC) Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Frankfurt Institute for Advances Studies. Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Manuel, Cristina [Instituto de Ciencias del Espacio (IEEC/CSIC) Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Sarkar, Sreemoyee [Tata Institute of Fundamental Research, Homi Bhaba Road, Mumbai-400005 (India); Tarrus, Jaume [Physik Department, Technische Universität München, D-85748 Garching (Germany)

    2016-01-22

    We study the shear and bulk viscosity coefficients as well as the thermal conductivity as arising from the collisions among phonons in superfluid neutron stars. We use effective field theory techniques to extract the allowed phonon collisional processes, written as a function of the equation of state and the gap of the system. The shear viscosity due to phonon scattering is compared to calculations of that coming from electron collisions. We also comment on the possible consequences for r-mode damping in superfluid neutron stars. Moreover, we find that phonon collisions give the leading contribution to the bulk viscosities in the core of the neutron stars. We finally obtain a temperature-independent thermal conductivity from phonon collisions and compare it with the electron-muon thermal conductivity in superfluid neutron stars.

  8. Molar extinction coefficients of some fatty acids

    Science.gov (United States)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  9. EXTENDED CLUSTERING COEFFICIENTS:GENERALIZATION OF CLUSTERING COEFFICIENTS IN SMALL-WORLD NETWORKS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The clustering coefficient C of a network, which is a measure of direct connectivity between neighbors of the various nodes, ranges from 0 (for no connectivity) to 1 (for full connectivity). We define extended clustering coefficients C(h) of a small-world network based on nodes that are at distance h from a source node, thus generalizing distance-1 neighborhoods employed in computing the ordinary clustering coefficient C = C(1). Based on known results about the distance distribution Pδ(h) in a network, that is, the probability that a randomly chosen pair of vertices have distance h, we derive and experimentally validate the law Pδ(h)C(h) ≤ c log N / N, where c is a small constant that seldom exceeds 1. This result is significant because it shows that the product Pδ(h)C(h) is upper-bounded by a value that is considerably smaller than the product of maximum values for Pδ(h) and C(h). Extended clustering coefficients and laws that govern them offer new insights into the structure of small-world networks and open up avenues for further exploration of their properties.

  10. The Attenuation of Correlation Coefficients: A Statistical Literacy Issue

    Science.gov (United States)

    Trafimow, David

    2016-01-01

    Much of the science reported in the media depends on correlation coefficients. But the size of correlation coefficients depends, in part, on the reliability with which the correlated variables are measured. Understanding this is a statistical literacy issue.

  11. Recovering DC coefficients in block-based DCT.

    Science.gov (United States)

    Uehara, Takeyuki; Safavi-Naini, Reihaneh; Ogunbona, Philip

    2006-11-01

    It is a common approach for JPEG and MPEG encryption systems to provide higher protection for dc coefficients and less protection for ac coefficients. Some authors have employed a cryptographic encryption algorithm for the dc coefficients and left the ac coefficients to techniques based on random permutation lists which are known to be weak against known-plaintext and chosen-ciphertext attacks. In this paper we show that in block-based DCT, it is possible to recover dc coefficients from ac coefficients with reasonable image quality and show the insecurity of image encryption methods which rely on the encryption of dc values using a cryptoalgorithm. The method proposed in this paper combines dc recovery from ac coefficients and the fact that ac coefficients can be recovered using a chosen ciphertext attack. We demonstrate that a method proposed by Tang to encrypt and decrypt MPEG video can be completely broken. PMID:17076416

  12. Inverse Coefficient Problems for Nonlinear Parabolic Differential Equations

    Institute of Scientific and Technical Information of China (English)

    Yun Hua OU; Alemdar HASANOV; Zhen Hai LIU

    2008-01-01

    This paper is devoted to a class of inverse problems for a nonlinear parabolic differential equation.The unknown coefficient of the equation depends on the gradient of the solution and belongs to a set of admissible coefficients.It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence.Based on this result the existence of a quasisolution of the inverse problem is obtained in the appropriate class of admissible coefficients.

  13. Inverse Coefficient Problems for Nonlinear Elliptic Variational Inequalities

    Institute of Scientific and Technical Information of China (English)

    Run-sheng Yang; Yun-hua Ou

    2011-01-01

    This paper is devoted to a class of inverse coefficient problems for nonlinear elliptic variational inequalities. The unknown coefficient of elliptic variational inequalities depends on the gradient of the solution and belongs to a set of admissible coefficients. It is shown that the nonlinear elliptic variational inequalities is unique solvable for the given class of coefficients. The existence of quasisolutions of the inverse problems is obtained.

  14. PEARSON'S OR SPEARMAN'S CORRELATION COEFFICIENT - WHICH ONE TO USE?

    OpenAIRE

    Andrijana Rebekić; Zdenko Lončarić; Sonja Petrović; Sonja Marić

    2015-01-01

    Mosf commonly used correlation coefficients are Pearson's product moment correlation coefficient and Spearman's rank correlation coefficient. The aim of this paper is to compare a Pearson's and Spearman's coefficient of correlation on the same data set. The winter wheat grain cadmium (Cd) concentration was correlated to grain zinc (Zn) concentration, plant height, plant weight, number of spikelets per spike and 1000 kernel weight. Data were collected from the experiment carried out in semi co...

  15. Estimating crop coefficients from fraction of ground cover and height

    OpenAIRE

    Allen, Richard G.; L. S. Pereira

    2009-01-01

    The FAO-56 procedure for estimating the crop coefficient Kc as a function of fraction of ground cover and crop height has been formalized in this study using a density coefficient Kd. The density coefficient is multiplied by a basal Kc representing full cover conditions, Kcb full, to produce a basal crop coefficient that represents actual conditions of ET and vegetation coverage when the soil surface is dry. Kcb full is estimated primarily as a function of crop height....

  16. EXACT SAMPLING DISTRIBUTION OF SAMPLE COEFFICIENT OF VARIATION

    OpenAIRE

    Dr.G.S.David Sam Jayakumar; A.Sulthan

    2015-01-01

    This paper proposes the sampling distribution of sample coefficient of variation from the normal population. We have derived the relationship between the sample coefficient of variation, standard normal and chi-square variate. We have derived density function of the sample coefficient of variation in terms of the confluent hyper-geometric distribution. Moreover, the first two moments of the distribution are derived and we have proved that the sample coefficient of variation (cv...

  17. On the Occurrence of Standardized Regression Coefficients Greater than One.

    Science.gov (United States)

    Deegan, John, Jr.

    1978-01-01

    It is demonstrated here that standardized regression coefficients greater than one can legitimately occur. Furthermore, the relationship between the occurrence of such coefficients and the extent of multicollinearity present among the set of predictor variables in an equation is examined. Comments on the interpretation of these coefficients are…

  18. Interpretation of Standardized Regression Coefficients in Multiple Regression.

    Science.gov (United States)

    Thayer, Jerome D.

    The extent to which standardized regression coefficients (beta values) can be used to determine the importance of a variable in an equation was explored. The beta value and the part correlation coefficient--also called the semi-partial correlation coefficient and reported in squared form as the incremental "r squared"--were compared for variables…

  19. The Discharge Coefficient of a Centre-Pivot Roof Window

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Afshari, Alireza; Nielsen, Peter V.;

    2012-01-01

    value of discharge coefficient is used. The constant value of discharge coefficient leads to deceptive airflow estimation in the cases of centre-pivot roof windows. The object of this paper is to study and evaluate the discharge coefficient of the centre pivot roof window. Focus is given on...

  20. On some properties of SU(3) Fusion Coefficients

    CERN Document Server

    Coquereaux, Robert

    2016-01-01

    Three aspects of the SU(3) fusion coefficients are revisited: the generating polynomials of fusion coefficients are written explicitly; some curious identities generalizing the classical Freudenthal-de Vries formula are derived; and the properties of the fusion coefficients under conjugation of one of the factors, previously analysed in the classical case, are extended to the affine algebra of su(3) at finite level.

  1. General Symmetry Approach to Solve Variable-Coefficient Nonlinear Equations

    Institute of Scientific and Technical Information of China (English)

    RUAN HangYu; CHEN YiXin; LOU SenYue

    2001-01-01

    After considering the variable coefficient of a nonlinear equation as a new dependent variable, some special types of variable-coefficient equation can be solved from the corresponding constant-coefficient equations by using the general classical Lie approach. Taking the nonlinear Schrodinger equation as a concrete example, the method is recommended in detail.``

  2. Transport coefficients in the P3 and P5 approximations

    International Nuclear Information System (INIS)

    Several procedures to account for space dependence of diffusion coefficients can be found in the literature. In this work, a relationship between neutron current and flux in the P3 and P5 approximations (generalized Fick's law) is obtained. Thermal neutron diffusion coefficient and other transport coefficients are found in P2 and P3 approximations. (author)

  3. Transport coefficients of a relativistic plasma

    Science.gov (United States)

    Pike, O. J.; Rose, S. J.

    2016-05-01

    In this work, a self-consistent transport theory for a relativistic plasma is developed. Using the notation of Braginskii [S. I. Braginskii, in Reviews of Plasma Physics, edited by M. A. Leontovich (Consultants Bureau, New York, 1965), Vol. 1, p. 174], we provide semianalytical forms of the electrical resistivity, thermoelectric, and thermal conductivity tensors for a Lorentzian plasma in a magnetic field. This treatment is then generalized to plasmas with arbitrary atomic number by numerically solving the linearized Boltzmann equation. The corresponding transport coefficients are fitted by rational functions in order to make them suitable for use in radiation-hydrodynamic simulations and transport calculations. Within the confines of linear transport theory and on the assumption that the plasma is optically thin, our results are valid for temperatures up to a few MeV. By contrast, classical transport theory begins to incur significant errors above kBT ˜10 keV, e.g., the parallel thermal conductivity is suppressed by 15% at kBT =20 keV due to relativistic effects.

  4. Townsend coefficients of gases in avalanche counters

    International Nuclear Information System (INIS)

    Though much work has been done by many authors in the last few years in the development and application of avalanche counters for ion radiation, it is based upon values of the Townsend coefficients as the essential gas parameter, which were determined many years ago for much lower reduced field strengths F/p than prevail in such counters. Therefore absolute determinations of α in vapours of methyl alcohol, cyclohexane, acetone, and n-heptene were performed under original conditions of avalanche counters. The values obtained do not differ by more than 30%-50% from the former values indeed, extrapolated over F/p for the first three mentioned substances, but the amounts of A and B in the usual representation α/p=A exp(-B(F/p)) are much greater for the stronger reduced fields. This is of importance for such counter properties as the dependence of pulse heights on pressure, voltage, electrode distance etc., which are governed by other combinations of A and B than α/p itself. A comparison of results for different ionic radiations shows a marked influence of the primary ionization density along the particle tracks which is hard to explain. (Auth.)

  5. Measurements of soil-solution distribution coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Hirofumi; Hasegawa, Hidenao; Hisamatsu, Shunichi; Sakurai, Naoyuki; Koyama, Kenji [Institute for Environmental Sciences, Department of Radioecology, Rokkasho, Aomori (Japan)

    1999-07-01

    The soil-solution distribution coefficient (Kd) is defined as the ratio of element concentrations in a soil-solid phase to that in a solution phase. It is commonly used as an important parameter for transfer models of radionuclides in different environments, such as describing the migration behavior in the geosphere and transfer behavior in the biosphere. We plan to measure the Kd of elements by means of an extraction method in soils throughout Aomori Prefecture and to probe related factors affecting their variance. However, Kd values vary widely, dependent upon conditions of measurements even if a similar soil sample is measured. Therefore, measurement conditions for the Kd of elements were examined in the present study and the following conditions were adopted. A collected soil sample was passed through a 2 mm sieve and dried at 50degC. The ratio of solution to solid was 10. The mixture sample was shaken for 24 h at 20degC in a clean centrifuge bottle which was made of polypropylene copolymer (PPCO). According to the literature, common soil types in Aomori Prefecture are as follows: andosols in the Sanpachi-Kamikita region, gray lowland and upland soils in the Tsugaru region, sand-dune regosols in Kizukuri-machi, peat soils around lakes and so on. The Kd values for those soil types will be measured hereafter. (author)

  6. Pulmonary interstitial compliance and microvascular filtration coefficient.

    Science.gov (United States)

    Goldberg, H S

    1980-08-01

    Static and dynamic properties governing the fluid movement into the pulmonary interstitium were examined in isolated canine lobes. The system was driven by altering intravascular presure (Piv) when the lobe was isogravimetric (change in weight (W) = 0) and allowing the lobe to become isogravimetric again. By making use of an analogy to charging a capacitor across a resistor, calculation of the filtration coefficient for transvascular fluid movement (KF) and determination of the pressure-volume relationship of the pulmonary interstitial space (Pis-Vis), with a minimum of untested assumptions, was possible. KF was found to be the same for fluid moving out of or into the intravascular space, and when the relationship between Piv and alveolar pressure (PAlv) was constant, KF was independent of transpulmonary pressure (PL). When PAlv exceeded Piv, changes in Piv did not influence KF, suggesting no significant change in either surface area available for fluid transudation or vascular permeability. The Pis-Vis curve for increasing values of Vis and Pis is best described by an exponential relationhip and is independent of PL. However, the Pis-Vis curve with decreasing values of Vis and Pis is dependent on PL.

  7. Coefficient of Performance Enhancement of Refrigeration Cycles

    Directory of Open Access Journals (Sweden)

    Eng. Naser R. M. AL-Ajmi

    2015-03-01

    Full Text Available Refrigerator is one of the home appliance utilizing mechanical vapor compression cycle in its process. Performance of the systems become the main issue and many researches are still ongoing to evaluate and improve the efficiency of any used system. Therefore, this paper presents an experimental investigation of the performance of the refrigeration cycles. A small rrefrigerator is used as the test rig. The Coefficient of Performance (COP is studied by using different condenser designs and under varying evaporator loads. Three condenser designs are used in present work. These condensers are regular condenser of domestic refrigerator, condenser with copper plain tubes (Cond.1 and condenser with copper tubes welded with stainless steel flat plate (Cond.2. pressures and temperatures measurements of each point in the refrigeration cycle are collected in order to evaluate the refrigerator performance. The results showed that the average COP of Cond.1 and Cond.2 are increased up to 20 % and 14% respectively more than regular condenser design under no load. The evaporator load effects on the machine performance, where the COP of the machine increases with the increase of the evaporator load.

  8. The intraclass correlation coefficient: distribution-free definition and test.

    Science.gov (United States)

    Commenges, D; Jacqmin, H

    1994-06-01

    A definition of the intraclass correlation coefficient is given on the basis of a general class of random effect model. The conventional intraclass correlation coefficient and the intracluster correlation coefficient for binary data are both particular cases of the generalized coefficient. We derive the score test for the hypothesis of null intraclass correlation in the exponential family. The statistic does not depend on the particular distribution in this family and is related to the pairwise correlation coefficient. The test can be adjusted for explanatory variables.

  9. Systematic Risk on Istanbul Stock Exchange: Traditional Beta Coefficient Versus Downside Beta Coefficient

    Directory of Open Access Journals (Sweden)

    Gülfen TUNA

    2013-03-01

    Full Text Available The aim of this study is to test the validity of Downside Capital Asset Pricing Model (D-CAPM on the ISE. At the same time, the explanatory power of CAPM's traditional beta and D-CAPM's downside beta on the changes in the average return values are examined comparatively. In this context, the monthly data for seventy three stocks that are continuously traded on the ISE for the period 1991-2009 is used. Regression analysis is applied in this study. The research results have shown that D-CAPM is valid on the ISE. In addition, it is obtained that the power of downside beta coefficient is higher than traditional beta coefficient on explaining the return changes. Therefore, it can be said that the downside beta is superior to traditional beta in the ISE for chosen period.

  10. Methods for Accurate Free Flight Measurement of Drag Coefficients

    CERN Document Server

    Courtney, Elya; Courtney, Michael

    2015-01-01

    This paper describes experimental methods for free flight measurement of drag coefficients to an accuracy of approximately 1%. There are two main methods of determining free flight drag coefficients, or equivalent ballistic coefficients: 1) measuring near and far velocities over a known distance and 2) measuring a near velocity and time of flight over a known distance. Atmospheric conditions must also be known and nearly constant over the flight path. A number of tradeoffs are important when designing experiments to accurately determine drag coefficients. The flight distance must be large enough so that the projectile's loss of velocity is significant compared with its initial velocity and much larger than the uncertainty in the near and/or far velocity measurements. On the other hand, since drag coefficients and ballistic coefficients both depend on velocity, the change in velocity over the flight path should be small enough that the average drag coefficient over the path (which is what is really determined)...

  11. Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

    Directory of Open Access Journals (Sweden)

    Osamu Kuwano

    2012-01-01

    Full Text Available Electrokinetic phenomena are believed to be the most likely origin of electromagnetic signals preceding or accompanying earthquakes. The intensity of the source current due to the electrokinetic phenomena is determined by the fluid flux and the electrokinetic coupling coefficient called streaming current coefficient; therefore, how the coefficient changes before rupture is essential. Here, we show how the electrokinetic coefficients change during the rock deformation experiment up to failure. The streaming current coefficient did not increase before failure, but continued to decrease up to failure, which is explained in terms of the elastic closure of capillary. On the other hand, the streaming potential coefficient, which is the product of the streaming current coefficient and bulk resistivity of the rock, increased at the onset of dilatancy. It may be due to change in bulk resistivity. Our result indicates that the zeta potential of the newly created surface does not change so much from that of the preexisting fluid rock interface.

  12. Roughness coefficient and its uncertainty in gravel-bed river

    Institute of Scientific and Technical Information of China (English)

    Ji-Sung KIM; Chan-Joo LEE; Won KIM; Yong-Jeon KIM

    2010-01-01

    Manning's roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge,and the applicability of various methods used for estimation of the roughness coefficient was evaluated.Results show that the roughness coefficient tends to decrease with increasing discharge and water depth,and over a certain range it appears to remain constant.Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that,although the field-measured values provide approximate roughness coefficients for relatively large discharge,there seems to be rather high uncertainty due to the difference in resultant values.For this reason,uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables.On average,a 20%increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity,but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach.Finally,the validity of estimated roughness coefficient based on field measurements was examined.A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation,but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%.Conversely,the necessity for roughness coefficient estimation by field measurement is confirmed.

  13. Survivor dosimetry. Part A. Fluence-to-kerma conversion coefficients

    International Nuclear Information System (INIS)

    An important step in the dosimetry evaluation is to relate the radiation passing through a unit volume of a material of interest (fluence) to the energy release (kerma) in the material, which determines the absorbed dose. The fluence-to-kerma conversion coefficients or 'kerma coefficients' used in the Dosimetry System 1986 (DS86) are taken from Kerr (1982). These kerma coefficients are based on body tissue compositions for Reference Man from the International Commission on Radiological Protection (1975) and Kerr (1982), the mass energy-absorption coefficients for photons from Hubbell (1982), and the elemental kerma coefficients for neutrons from Caswell et al. (1980). Hence, the kerma coefficients used in DS86 are approximately 20 years old. In order to provide an updated set of kerma coefficients for use in the Dosimetry System 2002 (DS02), a new evaluation has been completed. This new evaluation considered recently suggested changes in the composition of soft tissues of the body in ICRU Report 44 (International Commission on Radiation Units and Measurements 1989), the mass energy-absorption coefficients for photons by Hubbell and Seltzer (1996), and the elemental kerma coefficients for neutrons in ICRU Report 63 (International Commission on Radiation Units and Measurements 2000). The new DS02 kerma coefficients for soft tissue are presented as both point-wise data for use in Monte Carlo radiation transport calculations and multigroup data for use in discrete ordinates radiation transport calculations. (author)

  14. Fusion of Daubechies Wavelet Coefficients for Human Face Recognition

    CERN Document Server

    Bhowmik, Mrinal Kanti; Nasipuri, Mita; Basu, Dipak Kumar; Kundu, Mahantapas

    2010-01-01

    In this paper fusion of visual and thermal images in wavelet transformed domain has been presented. Here, Daubechies wavelet transform, called as D2, coefficients from visual and corresponding coefficients computed in the same manner from thermal images are combined to get fused coefficients. After decomposition up to fifth level (Level 5) fusion of coefficients is done. Inverse Daubechies wavelet transform of those coefficients gives us fused face images. The main advantage of using wavelet transform is that it is well-suited to manage different image resolution and allows the image decomposition in different kinds of coefficients, while preserving the image information. Fused images thus found are passed through Principal Component Analysis (PCA) for reduction of dimensions and then those reduced fused images are classified using a multi-layer perceptron. For experiments IRIS Thermal/Visual Face Database was used. Experimental results show that the performance of the approach presented here achieves maximum...

  15. Personal dose-equivalent conversion coefficients for 1252 radionuclides.

    Science.gov (United States)

    Otto, Thomas

    2016-01-01

    Dose conversion coefficients for radionuclides are useful for routine calculations in radiation protection in industry, medicine and research. They give a simple and often sufficient estimate of dose rates during production, handling and storage of radionuclide sources, based solely on the source's activity. The latest compilation of such conversion coefficients dates from 20 y ago, based on nuclear decay data published 30 y ago. The present publication provides radionuclide-specific conversion coefficients to personal dose based on the most recent evaluations of nuclear decay data for 1252 radionuclides and fluence-to-dose-equivalent conversion coefficients for monoenergetic radiations. It contains previously unknown conversion coefficients for >400 nuclides and corrects those conversion coefficients that were based on erroneous decay schemes. For the first time, estimates for the protection quantity Hp(3) are included.

  16. EXACT SAMPLING DISTRIBUTION OF SAMPLE COEFFICIENT OF VARIATION

    Directory of Open Access Journals (Sweden)

    Dr.G.S.David Sam Jayakumar

    2015-06-01

    Full Text Available This paper proposes the sampling distribution of sample coefficient of variation from the normal population. We have derived the relationship between the sample coefficient of variation, standard normal and chi-square variate. We have derived density function of the sample coefficient of variation in terms of the confluent hyper-geometric distribution. Moreover, the first two moments of the distribution are derived and we have proved that the sample coefficient of variation (cv is the biased estimator of the population coefficient of variation (CV. Moreover, the shape of the density function of sample co-efficient of variation is also visualized and the critical points of sample (cv at 5% and 1% level of significance for different sample sizes have also been computed.

  17. Investigating Diffusion Coefficient Using Dynamic Light Scattering Technique

    OpenAIRE

    Sun, Yong

    2006-01-01

    In this work, the Z-average, effective, apparent diffusion coefficients and their poly-dispersity indexes were investigated for dilute poly-disperse homogeneous spherical particles in dispersion where the Rayleigh-Gans-Debye approximation is valid. The results reveal that the values of the apparent and effective diffusion coefficients at a scattering angle investigated are consistent and the difference between the effective and Z-average diffusion coefficients is a function of the mean partic...

  18. On the Connection Coefficients of the Chebyshev-Boubaker Polynomials

    Directory of Open Access Journals (Sweden)

    Paul Barry

    2013-01-01

    Full Text Available The Chebyshev-Boubaker polynomials are the orthogonal polynomials whose coefficient arrays are defined by ordinary Riordan arrays. Examples include the Chebyshev polynomials of the second kind and the Boubaker polynomials. We study the connection coefficients of this class of orthogonal polynomials, indicating how Riordan array techniques can lead to closed-form expressions for these connection coefficients as well as recurrence relations that define them.

  19. Estimation of cavitation limits from local head loss coefficient

    OpenAIRE

    Sánchez Calvo, Raúl; Juana Sirgado, Luis; Laguna Peñuelas, Francisco; Rodríguez Sinobas, Leonor

    2008-01-01

    Cavitation effects in valves and other sudden transitions in water distribution systems are studied as their better understanding and quantification is needed for design and analysis purposes and for predicting and controlling their operation. Two dimensionless coefficients are used to characterize and verify local effects under cavitating flow conditions: the coefficient of local head losses and the minimum value of the cavitation number. In principle, both coefficients must be determined ex...

  20. Scanning measurement of Seebeck coefficient of a heated sample

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, G. Jeffrey; Iwanaga, Shiho

    2016-04-19

    A novel scanning Seebeck coefficient measurement technique is disclosed utilizing a cold scanning thermocouple probe tip on heated bulk and thin film samples. The system measures variations in the Seebeck coefficient within the samples. The apparatus may be used for two dimensional mapping of the Seebeck coefficient on the bulk and thin film samples. This technique can be utilized for detection of defective regions, as well as phase separations in the sub-mm range of various thermoelectric materials.

  1. The Frictional Coefficient of Bovine Knee Articular Cartilage

    Institute of Scientific and Technical Information of China (English)

    Qian Shan-hua; Ge Shi-rong; Wang Qing-liang

    2006-01-01

    The normal displacement of articular cartilage was measured under load and in sliding, and the coefficient of friction during sliding was measured using a UMT-2 Multi-Specimen Test System. The maximum normal displacement under load and the start-up frictional coefficient have similar tendency of variation with loading time. The sliding speed does not significantly influence the frictional coefficient of articular cartilage.

  2. ON TESTING THE EQUALITY OF K MULTIPLEAND PARTIAL CORRELATION COEFFICIENTS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Coutsourides (1980) derives an ad hoc nuisance parameter removal test for testing the equality of two multiple correlation coefficients of two independent p variate normal populations, under the assumption that a sample of size n is available from each population. He also extends his ad hoc nuisance parameter removal test to the testing of the equality of two multiple correlation matrices. This paper presents likelihood ratio tests for testing the equality of k multiple correlation coefficients, and also k partial correlation coefficients.

  3. A new approach to bootstrap inference in functional coefficient models

    OpenAIRE

    Herwartz, Helmut; Xu, Fang

    2007-01-01

    We introduce a new, factor based bootstrap approach which is robust under heteroskedastic error terms for inference in functional coefficient models. Modeling the functional coefficient parametrically, the bootstrap approximation of an F statistic is shown to hold asymptotically. In simulation studies with both parametric and nonparametric functional coefficients, factor based bootstrap inference outperforms the wild bootstrap and pairs bootstrap approach according to its size features. Apply...

  4. Consideration on Singularities in Learning Theory and the Learning Coefficient

    OpenAIRE

    Miki Aoyagi

    2013-01-01

    We consider the learning coefficients in learning theory and give two new methods for obtaining these coefficients in a homogeneous case: a method for finding a deepest singular point and a method to add variables. In application to Vandermonde matrix-type singularities, we show that these methods are effective. The learning coefficient of the generalization error in Bayesian estimation serves to measure the learning efficiency in singular learning models. Mathematically, the learning coeffic...

  5. Some comments on `Equation for the second virial coefficient`

    OpenAIRE

    Umirzakov, I. H.

    2013-01-01

    The second viral coefficient calculated using the equation suggested in the paper of Kaplun A.B., Meshalkin A.B. Equation for the second virial coefficient published in High temperature high pressure, 1999, Volume 31, pages 253-258 is compared with experimental data for helium, hydrogen, neon, argon, krypton, xenon, carbon dioxide, water, ammonia, methane, ethylene. It is shown the formula cannot describe the temperature dependence of the experimental data on the second virial coefficient for...

  6. Zero Pearson Coefficient for Strongly Correlated Growing Trees

    OpenAIRE

    Dorogovtsev S.N.; Ferreira A.L.; Goltsev A.V.; Mendes J.F.F.

    2009-01-01

    We obtained Pearson's coefficient of strongly correlated recursive networks growing by preferential attachment of every new vertex by $m$ edges. We found that the Pearson coefficient is exactly zero in the infinite network limit for the recursive trees ($m=1$). If the number of connections of new vertices exceeds one ($m>1$), then the Pearson coefficient in the infinite networks equals zero only when the degree distribution exponent $\\gamma$ does not exceed 4. We calculated the Pearson coeffi...

  7. A Meta-analysis of Cronbach's Coefficient Alpha.

    OpenAIRE

    Robert A. Peterson

    1994-01-01

    Despite some limitations, Cronbach's coefficient alpha remains the most widely used measure of scale reliability. The purpose of this article was to empirically document the magnitudes of alpha coefficients obtained in behavioral research, compare these obtained values with guidelines and recommendations set forth by individuals such as Nunnally (1967, 1978), and provide insights into research design characteristics that may influence the size of coefficient alpha. Average reported alpha coef...

  8. Improvement of Similarity Measure: Pearson Product-Moment Correlation Coefficient

    Institute of Scientific and Technical Information of China (English)

    LIUYong-suo; MENGQing-hua; CHENRong; WANGJian-song; JIANGShu-min; HUYu-zhu

    2004-01-01

    Aim To study the reason of the insensitiveness of Pearson preduct-moment correlation coefficient as a similarity measure and the method to improve its sensitivity. Methods Experimental and simulated data sets were used. Results The distribution range of the data sets influences the sensitivity of Pearson product-moment correlation coefficient. Weighted Pearson product-moment correlation coefficient is more sensitive when the range of the data set is large. Conclusion Weighted Pearson product-moment correlation coefficient is necessary when the range of the data set is large.

  9. Classification of coefficients of variation in experiments with commercial layers

    Directory of Open Access Journals (Sweden)

    DE Faria Filho

    2010-12-01

    Full Text Available This study aimed at determining a specific classification of coefficients of variation in experiments with commercial layers. Coefficients of variation were collected from papers published in Brazilian journals between 2000 and 2009 for performance, internal egg quality, and eggshell quality parameters. The coefficients of variation of each parameter were classified as low, intermediate, high, and very high according to the ratio between the median and the pseudo-sigma. It was concluded that the parameters used in experiments with commercial layers have a specific classification of coefficients of variation, and that this must be considered to evaluate experimental accuracy.

  10. Correlation Degree and Correlation Coefficient of Multi- Output Functions

    Institute of Scientific and Technical Information of China (English)

    JU Gui-zhi; ZHAO Ya-qun

    2005-01-01

    We present definitions of the correlation degree and correlation coefficient of multi-output functions. Two relationships about the correlation degree of multi-output functions are proved. One is between the correlation degree and independency,the other is between the correlation degree and balance. Especially the paper discusses the correlation degree of affine multioutput functions. We demonstrate properties of the correlation coefficient of multi-output functions. One is the value range of the correlation coefficient, one is the relationship between the correlation coefficient and independency, and another is the sufficient and necessary condition that two multi-output functions are equivalent to each other.

  11. Influence of Dynamical Change of Edges on Clustering Coefficients

    Directory of Open Access Journals (Sweden)

    Yuhong Ruan

    2015-01-01

    Full Text Available Clustering coefficient is a very important measurement in complex networks, and it describes the average ratio between the actual existent edges and probable existent edges in the neighbor of one vertex in a complex network. Besides, in a complex networks, the dynamic change of edges can trigger directly the evolution of network and further affect the clustering coefficients. As a result, in this paper, we investigate the effects of the dynamic change of edge on the clustering coefficients. It is illustrated that the increase and decrease of the clustering coefficient can be effectively controlled by adding or deleting several edges of the network in the evolution of complex networks.

  12. Consideration on Singularities in Learning Theory and the Learning Coefficient

    Directory of Open Access Journals (Sweden)

    Miki Aoyagi

    2013-09-01

    Full Text Available We consider the learning coefficients in learning theory and give two new methods for obtaining these coefficients in a homogeneous case: a method for finding a deepest singular point and a method to add variables. In application to Vandermonde matrix-type singularities, we show that these methods are effective. The learning coefficient of the generalization error in Bayesian estimation serves to measure the learning efficiency in singular learning models. Mathematically, the learning coefficient corresponds to a real log canonical threshold of singularities for the Kullback functions (relative entropy in learning theory.

  13. Repeatability study of mechanomyography in submaximal isometric contractions using coefficient of variation and intraclass correlation coefficient.

    Science.gov (United States)

    Akataki, K; Mita, K; Itoh, Y

    1999-01-01

    The within-day and between-day repeatability of the mechanomyogram (MMG) was assessed using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC) and was compared with that of the electromyogram (EMG). The MMG and EMG were recorded simultaneously during isometric elbow flexion trials at different submaximal levels of 10% to 90% MVC. The testing session consisting of 9 submaximal trials was repeated 8 times on the same day for estimation of the within-day variation. In order to examine the between-day variation, the same testing session was also performed 8 times over 3 weeks with a 2-day rest interval between each session. The CVs within-day and between-day in both the MMG and EMG did not demonstrate any significant differences relating to the magnitude of force exerted. The CVs combined over all the force levels were approximately 10% within the same day and 25% between days for both the MMG and EMG. These corresponded to the within-day ICC of approximately 0.95 and the between-day ICC of 0.80. The repeatability of the MMG during submaximal isometric contractions of biceps brachii muscles is considered to be similar to that of the more established EMG.

  14. A Note on the Correlated Random Coefficient Model

    DEFF Research Database (Denmark)

    Kolodziejczyk, Christophe

    In this note we derive the bias of the OLS estimator for a correlated random coefficient model with one random coefficient, but which is correlated with a binary variable. We provide set-identification to the parameters of interest of the model. We also show how to reduce the bias of the estimator...

  15. Coefficients for tests from a decision theoretic point of view

    NARCIS (Netherlands)

    Linden, van der Wim J.; Mellenbergh, Gideon J.

    1978-01-01

    From a decision theoretic point of view a general coefficient for tests, d, is derived. The coefficient is applied to three kinds of decision situations. First, the situation is considered in which a true score is estimated by a function of the observed score of a subject on a test (point estimation

  16. Choice of the Ångström-Prescott coefficients

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Mei, Xurong; Li, Yuzhong;

    2010-01-01

    (fixed) coefficients using data from 20 sites of temperate climate in China. When evaluated by performance indicators of RMSE, RRMSE, MBE, R2 and values of t-statistic, it is demonstrated that time-dependent A–P coefficients are not better than fixed ones in Rs prediction. This indicates...

  17. Visualising the Roots of Quadratic Equations with Complex Coefficients

    Science.gov (United States)

    Bardell, Nicholas S.

    2014-01-01

    This paper is a natural extension of the root visualisation techniques first presented by Bardell (2012) for quadratic equations with real coefficients. Consideration is now given to the familiar quadratic equation "y = ax[superscript 2] + bx + c" in which the coefficients "a," "b," "c" are generally…

  18. Permeability dependence of streaming potential coefficient in porous media

    NARCIS (Netherlands)

    L.D. Thanh; R. Sprik

    2015-01-01

    In theory, the streaming potential coefficient depends not only on the zeta potential but also on the permeability of the rocks that partially determines the surface conductivity of the rocks. However, in practice, it is hard to show the permeability dependence of streaming potential coefficients be

  19. Mass transfer coefficients in cross-flow ultrafiltration

    NARCIS (Netherlands)

    Berg, van den G.B.; Rácz, I.G.; Smolders, C.A.

    1989-01-01

    Usually, in concentration polarization models, the mass transfer coefficient is an unknown parameter. Also, its variation with changing experimental circumstances is in question. In the literature, many relationships can be found to describe the mass transfer coefficient under various conditions, as

  20. Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale

    CERN Document Server

    Lane, Charles D

    2016-01-01

    When the Standard-Model Extension (SME) is applied in curved spacetime, the Lorentz-violation coefficients must depend on spacetime position. This work describes some of the consequences of this spacetime variation. We focus on effects that appear at a nonrelativistic scale and extract sensitivity of completed experiments to derivatives of SME coefficient fields.

  1. Delimiting Coefficient a from Internal Consistency and Unidimensionality

    Science.gov (United States)

    Sijtsma, Klaas

    2015-01-01

    I discuss the contribution by Davenport, Davison, Liou, & Love (2015) in which they relate reliability represented by coefficient a to formal definitions of internal consistency and unidimensionality, both proposed by Cronbach (1951). I argue that coefficient a is a lower bound to reliability and that concepts of internal consistency and…

  2. Scaling the Raman gain coefficient: Applications to Germanosilicate fibers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Bromage, J.; Stentz, A.J.;

    2003-01-01

    This paper presents a comprehensive analysis of the temperature dependence of a Raman amplifier and the scaling of the Raman gain coefficient with wavelength, modal overlap, and material composition. The temperature dependence is derived by applying a quantum theoretical description, whereas the...... scaling of the Raman gain coefficient is derived using a classical electromagnetic model. We also present experimental verification of our theoretical findings....

  3. Minimum wall pressure coefficient of orifice plate energy dissipater

    Directory of Open Access Journals (Sweden)

    Wan-zheng AI

    2015-01-01

    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  4. Anderson-Witting transport coefficients for flows in general relativity

    CERN Document Server

    Ambrus, Victor E

    2016-01-01

    The transport coefficients induced by the Anderson-Witting approximation of the collision term in the relativistic Boltzmann equation are derived for close to equilibrium flows in general relativity. Using the tetrad formalism, it is shown that the expression for these coefficients is the same as that obtained on flat space-time, in agreement with the generalized equivalence principle.

  5. Invariant coefficients of diffusion in iron-chromium-nickel system

    Energy Technology Data Exchange (ETDEWEB)

    Mokrov, A.P.; Akimov, V.K.; Golubev, V.G.

    1984-02-01

    The temperature and concentration dependences of the Dsub(c) coefficients in the ..gamma..-phase of iron-chromium-nickel system are determined. It is proposed to described mutual diffusion in multicomponent systems using invariant, i.e. independent of the choice of solvent, coefficients of diffusion. The assumption that their temperature dependence follows the Arrhenius law is confirmed by the experiment.

  6. Invariant coefficients of diffusion in iron-chromium-nickel system

    International Nuclear Information System (INIS)

    The temperature and concentration dependences of the Dsub(c) coefficients in the γ-phase of iron-chromium-nickel system are determined. It is proposed to described mutual diffusion in mul-- ticomponent systems using invariant, i. e. independent of the choice of solvent, coefficients of diffusion. The assumption that their temperature dependence follows the Arrhenius law is confirmed by the experiment

  7. Group classification of variable coefficient generalized Kawahara equations

    International Nuclear Information System (INIS)

    An exhaustive group classification of variable coefficient generalized Kawahara equations is carried out. As a result, we derive new variable coefficient nonlinear models admitting Lie symmetry extensions. All inequivalent Lie reductions of these equations to ordinary differential equations are performed. We also present some examples on the construction of exact and numerical solutions. (paper)

  8. Solitary Wave in Linear ODE with Variable Coefficients

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-Da; FU Zun-Tao; LIU Shi-Kuo; XIN Guo-Jun; LIANG Fu-Ming; FENG Bei-Ye

    2003-01-01

    In this paper, the linear ordinary differential equations with variable coefficients are obtained from thecontrolling equations satisfied by wavelet transform or atmospheric internal gravity waves, and these linear equationscan be further transformed into Weber equations. From Weber equations, the homoclinic orbit solutions can be derived,so the solitary wave solutions to linear equations with variable coefficients are obtained.

  9. 4-manifolds and intersection forms with local coefficients

    DEFF Research Database (Denmark)

    Frøyshov, Kim Anders

    2012-01-01

    We extend Donaldson's diagonalization theorem to intersection forms with certain local coefficients, under some constraints. This provides new examples of non-smoothable topological 4-manifolds.......We extend Donaldson's diagonalization theorem to intersection forms with certain local coefficients, under some constraints. This provides new examples of non-smoothable topological 4-manifolds....

  10. Digital speckle pattern interferometric measurement of diffusion coefficients in hydrogels

    Institute of Scientific and Technical Information of China (English)

    周金芳; 韩雁; 章献民; 徐坚

    2003-01-01

    The technique of real-time digital speckle pattern interferometry is proposed to study diffusion of surfactants in hydrogel. The diffusion coefficient is simply and directly determined from the interferograms. An example of diffusion coefficient measurement of surfactant in agarose gel demonstrates the usefulness of the method. The results obtained are compared with the theoretical simulating values.

  11. Minimum wall pressure coefficient of orifice plate energy dissipater

    Institute of Scientific and Technical Information of China (English)

    Wan-zheng Ai; Jia-hong Wang

    2015-01-01

    Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics:the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter;the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter;and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  12. The Evaluation of Connection Coefficients on an Interval

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A connection coefficient is an interval of products of wavelet basis functions,their derivatives and their tharnalstes.It can be used to solve PDEs numerically bv the wavelet-Galerkin method.This paper presents an exact method for evaluating connection coefficients on an interval.

  13. Uncertainty in wind pressure coefficients for low-rise buildings

    NARCIS (Netherlands)

    De Wit, M.S.

    1999-01-01

    This paper reports on an analysis of the uncertainty in wind pressure (difference) coefficients, which are assessed on the basis of generic knowledge and experimental data rather than with a specific (wind tunnel) experiment. The analysis is carried out on time averaged pressure coefficients in a sp

  14. Predicting blood:air partition coefficients using basic physicochemical properties

    NARCIS (Netherlands)

    Buist, H.E.; Wit-Bos, L. de; Bouwman, T.; Vaes, W.H.J.

    2012-01-01

    Quantitative Property Property Relationships (QPPRs) for human and rat blood:air partition coefficients (PBAs) have been derived, based on vapour pressure (Log(VP)), the octanol:water partition coefficient (Log(K_OW)) and molecular weight (MW), using partial least squares multilinear modelling. Thes

  15. Xenon tissue/blood partition coefficient for pig urinary bladder

    DEFF Research Database (Denmark)

    Nielsen, K K; Bülow, J; Nielsen, S L;

    1990-01-01

    In four landrace pigs the tissue/blood partition coefficient (lambda) for xenon (Xe) for the urinary bladder was calculated after chemical analysis for lipid, water and protein content and determination of the haematocrit. The coefficients varied from bladder to bladder owing to small differences...

  16. REE and Strontium Partition Coefficients for Nakhla Pyroxenes

    Science.gov (United States)

    Oe, K.; McKay, G.; Le, L.

    2001-01-01

    We present new partition coefficients for REE and Sr determined using a synthetic melt that crystallizes pyroxenes very similar in composition to Nakhla pyroxene cores. We believe these are the most appropriate partition coefficients to use in studying Nakhla Additional information is contained in the original extended abstract..

  17. Stochastic Modelling of the Diffusion Coefficient for Concrete

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In the paper, a new stochastic modelling of the diffusion coefficient D is presented. The modelling is based on physical understanding of the diffusion process and on some recent experimental results. The diffusion coefficients D is strongly dependent on the w/c ratio and the temperature....

  18. Limb-Darkening Coefficients for Eclipsing White Dwarfs

    CERN Document Server

    Gianninas, A; Kilic, Mukremin; Bergeron, P

    2013-01-01

    We present extensive calculations of linear and non-linear limb-darkening coefficients as well as complete intensity profiles appropriate for modeling the light-curves of eclipsing white dwarfs. We compute limb-darkening coefficients in the Johnson-Kron-Cousins UBVRI photometric system as well as the Large Synoptic Survey Telescope (LSST) ugrizy system using the most up-to-date model atmospheres available. In all, we provide the coefficients for seven different limb-darkening laws. We describe the variations of these coefficients as a function of the atmospheric parameters, including the effects of convection at low effective temperatures. Finally, we discuss the importance of having readily available limb-darkening coefficients in the context of present and future photometric surveys like the LSST, Palomar Transient Factory (PTF), and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The LSST, for example, may find ~10^5 eclipsing white dwarfs. The limb-darkening calculations presented h...

  19. Friction Coefficient of UHMWPE During Dry Reciprocating Sliding

    Directory of Open Access Journals (Sweden)

    F. Zivic

    2014-09-01

    Full Text Available This paper deals with the friction coefficient behaviour during dry reciprocating sliding of UHMWPE in contact with alumina (Al2O3, within a range of velocities typical for hip implants. Five values of normal force (100 - 1000 mN and three values of sliding speed (4 - 12 mm/s have been observed. Real time diagrams of the friction coefficient as a function of the sliding cycles were recorded for each test. Dynamic friction coefficient curves exhibited rather uniform behavior for all test conditions. Somewhat larger values of friction coefficient could be observed during the running-in period in case of low loads (100 - 250 mN and the lowest velocity (4 mm/s. In case of high loads and speeds, friction coefficient reached steady state values shortly after the beginning of the test.

  20. Calculation of effective absorption coefficient for aerosols of internal mixture

    International Nuclear Information System (INIS)

    The effective absorption coefficient with time of strong absorbing aerosol made of carbon dusts and water of internal mixture is analyzed, and the influence of different wavelengths and radius ratios on it is discussed. The shorter the wavelength is, the larger the effective absorption coefficient is , and more quickly it increases during 1-100 μs, and the largest increase if 132.65% during 1-100 μs. Different ratios between inner and outer radius have large influence on the effective absorption coefficient. The larger the ratio is, the larger the effective absorption coefficient is, and more quickly it increases during 1-100 μs. The increase of the effective absorption coefficient during 1-100 μs is larger than that during 100-1000 μs, and the largest increase is 138.66% during 1-100 μs. (authors)

  1. Determining pitch-angle diffusion coefficients from test particle simulations

    CERN Document Server

    Ivascenko, A; Spanier, F; Vainio, R

    2016-01-01

    Transport and acceleration of charged particles in turbulent media is a topic of great interest in space physics and interstellar astrophysics. These processes are dominated by the scattering of particles off magnetic irregularities. The scattering process itself is usually described by small-angle scattering with the pitch-angle coefficient $D_{\\mu\\mu}$ playing a major role. Since the diffusion coefficient $D_{\\mu\\mu}$ can be determined analytically only for the approximation of quasi-linear theory, the determination of this coefficient from numerical simulations has, therefore, become more important. So far these simulations yield particle tracks for small-scale scattering, which can then be interpreted using the running diffusion coefficients. This method has a limited range of validity. This paper presents two new methods that allow for the calculation of the pitch-angle diffusion coefficient from numerical simulations. These methods no longer analyse particle trajectories, but the change of particle dist...

  2. Determination of absolute internal conversion coefficients using the SAGE spectrometer

    Science.gov (United States)

    Sorri, J.; Greenlees, P. T.; Papadakis, P.; Konki, J.; Cox, D. M.; Auranen, K.; Partanen, J.; Sandzelius, M.; Pakarinen, J.; Rahkila, P.; Uusitalo, J.; Herzberg, R.-D.; Smallcombe, J.; Davies, P. J.; Barton, C. J.; Jenkins, D. G.

    2016-03-01

    A non-reference based method to determine internal conversion coefficients using the SAGE spectrometer is carried out for transitions in the nuclei of 154Sm, 152Sm and 166Yb. The Normalised-Peak-to-Gamma method is in general an efficient tool to extract internal conversion coefficients. However, in many cases the required well-known reference transitions are not available. The data analysis steps required to determine absolute internal conversion coefficients with the SAGE spectrometer are presented. In addition, several background suppression methods are introduced and an example of how ancillary detectors can be used to select specific reaction products is given. The results obtained for ground-state band E2 transitions show that the absolute internal conversion coefficients can be extracted using the methods described with a reasonable accuracy. In some cases of less intense transitions only an upper limit for the internal conversion coefficient could be given.

  3. Stochastic back analysis of permeability coefficient using generalized Bayesian method

    Institute of Scientific and Technical Information of China (English)

    Zheng Guilan; Wang Yuan; Wang Fei; Yang Jian

    2008-01-01

    Owing to the fact that the conventional deterministic back analysis of the permeability coefficient cannot reflect the uncertainties of parameters, including the hydraulic head at the boundary, the permeability coefficient and measured hydraulic head, a stochastic back analysis taking consideration of uncertainties of parameters was performed using the generalized Bayesian method. Based on the stochastic finite element method (SFEM) for a seepage field, the variable metric algorithm and the generalized Bayesian method, formulas for stochastic back analysis of the permeability coefficient were derived. A case study of seepage analysis of a sluice foundation was performed to illustrate the proposed method. The results indicate that, with the generalized Bayesian method that considers the uncertainties of measured hydraulic head, the permeability coefficient and the hydraulic head at the boundary, both the mean and standard deviation of the permeability coefficient can be obtained and the standard deviation is less than that obtained by the conventional Bayesian method. Therefore, the present method is valid and applicable.

  4. Optimization of Submarine Hydrodynamic Coefficients Based on Immune Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    HU Kun; XU Yi-fan

    2010-01-01

    Aiming at the demand for optimization of hydrodynamic coefficients in submarine's motion equations, an adaptive weight immune genetic algorithm was proposed to optimize hydrodynamic coefficients in motion equations. Some hydrody-namic coefficients of high sensitivity to control and maneuver were chosen as the optimization objects in the algorithm. By using adaptive weight method to determine the weight and target function, the multi-objective optimization could be transla-ted into single-objective optimization. For a certain kind of submarine, three typical maneuvers were chosen to be the objects of study: overshoot maneuver in horizontal plane, overshoot maneuver in vertical plane and turning circle maneuver in horizontal plane. From the results of computer simulations using primal hydrodynamic coefficient and optimized hydrody-namic coefficient, the efficiency of proposed method is proved.

  5. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    Science.gov (United States)

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  6. Dynamic sagittal flexibility coefficients of the human cervical spine.

    Science.gov (United States)

    Ivancic, Paul C; Ito, Shigeki; Panjabi, Manohar M

    2007-07-01

    The goal of the present study was to determine the dynamic sagittal flexibility coefficients, including coupling coefficients, throughout the human cervical spine using rear impacts. A biofidelic whole cervical spine model (n=6) with muscle force replication and surrogate head was rear impacted at 5 g peak horizontal accelerations of the T1 vertebra within a bench-top mini-sled. The dynamic main and coupling sagittal flexibility coefficients were calculated at each spinal level, head/C1 to C7/T1. The average flexibility coefficients were statistically compared (p<0.05) throughout the cervical spine. To validate the coefficients, the average computed displacement peaks, obtained using the average flexibility matrices and the measured load vectors, were statistically compared to the measured displacement peaks. The computed and measured displacement peaks showed good overall agreement, thus validating the computed flexibility coefficients. These peaks could not be statistically differentiated, with the exception of extension rotation at head/C1 and posterior shear translation at C7/T1. Head/C1 was significantly more flexible than all other spinal levels. The cervical spine was generally more flexible in posterior shear, as compared to axial compression. The coupling coefficients indicated that extension moment caused coupled posterior shear translation while posterior shear force caused coupled extension rotation. The present results may be used towards the designs of anthropometric test dummies and mathematical models that better simulate the cervical spine response during dynamic loading. PMID:17140545

  7. Transparent composite model for DCT coefficients: design and analysis.

    Science.gov (United States)

    Yang, En-Hui; Yu, Xiang; Meng, Jin; Sun, Chang

    2014-03-01

    The distributions of discrete cosine transform (DCT) coefficients of images are revisited on a per image base. To better handle, the heavy tail phenomenon commonly seen in the DCT coefficients, a new model dubbed a transparent composite model (TCM) is proposed and justified for both modeling accuracy and an additional data reduction capability. Given a sequence of the DCT coefficients, a TCM first separates the tail from the main body of the sequence. Then, a uniform distribution is used to model the DCT coefficients in the heavy tail, whereas a different parametric distribution is used to model data in the main body. The separate boundary and other parameters of the TCM can be estimated via maximum likelihood estimation. Efficient online algorithms are proposed for parameter estimation and their convergence is also proved. Experimental results based on Kullback-Leibler divergence and χ(2) test show that for real-valued continuous ac coefficients, the TCM based on truncated Laplacian offers the best tradeoff between modeling accuracy and complexity. For discrete or integer DCT coefficients, the discrete TCM based on truncated geometric distributions (GMTCM) models the ac coefficients more accurately than pure Laplacian models and generalized Gaussian models in majority cases while having simplicity and practicality similar to those of pure Laplacian models. In addition, it is demonstrated that the GMTCM also exhibits a good capability of data reduction or feature extraction-the DCT coefficients in the heavy tail identified by the GMTCM are truly outliers, and these outliers represent an outlier image revealing some unique global features of the image. Overall, the modeling performance and the data reduction feature of the GMTCM make it a desirable choice for modeling discrete or integer DCT coefficients in the real-world image or video applications, as summarized in a few of our further studies on quantization design, entropy coding design, and image understanding

  8. Inflationary Weak Anisotropic Model with General Dissipation Coefficient

    CERN Document Server

    Sharif, M

    2015-01-01

    This paper explores the dynamics of warm intermediate and logamediate inflationary models during weak dissipative regime with a general form of dissipative coefficient. We analyze these models within the framework of locally rotationally symmetric Bianchi type I universe. In both cases, we evaluate solution of inflaton, effective scalar potential, dissipative coefficient, slow-roll parameters, scalar and tensor power spectra, scalar spectral index and tensor to scalar ratio under slow-roll approximation. We constrain the model parameters using recent data and conclude that anisotropic inflationary universe model with generalized dissipation coefficient remains compatible with WMAP9, Planck and BICEP2 data.

  9. Thermal Conductivity and Heat Transfer Coefficient of Concrete

    Institute of Scientific and Technical Information of China (English)

    GUO Lixia; GUO Lei; ZHONG Ling; ZHU Yueming

    2011-01-01

    A very simple model for predicting thermal conductivity based on its definiensis was presented.The thermal conductivity obtained using the model provided a good coincidence to the investigations performed by other authors.The heat transfer coefficient was determined by inverse analysis using the temperature measurements.From experimental results,it is noted that heat transfer coefficient increases with the increase of wind velocity and relative humidity,a prediction equation on heat transfer coefficient about wind velocity and relative humidity is given.

  10. Static and dynamic effective stress coefficient of chalk

    DEFF Research Database (Denmark)

    Alam, M. Monzurul; Fabricius, Ida Lykke; Christensen, Helle Foged

    2012-01-01

    stress coefficient is thus relevant for studying reservoir deformation and for evaluating 4D seismic for the correct pore pressure prediction. The static effective stress coefficient n is estimated from mechanical tests and is highly relevant for effective stress prediction because it is directly related...... to mechanical strain in the elastic stress regime. The corresponding dynamic effective stress coefficient α is easy to estimate from density and velocity of acoustic (elastic) waves. We studied n and α of chalk from the reservoir zone of the Valhall field, North Sea, and found that n and α vary...

  11. Influence of effective stress coefficient on mechanical failure of chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.;

    2012-01-01

    and vice versa. However, as the effective stress working on the rock decreases with increased effective stress coefficient, the reduction of elastic region will have less effect on pore collapse strength if we consider the change in the effective stress coefficient. This finding will help estimate a more......, as this process could affect the grain contact cement. If this happens, the effective stress at the grain contacts in a reservoir will change according to the effective stress principle of Biot. In a p′-q space for failure analysis, we observed that a higher effective stress coefficient reduces the elastic region...

  12. Ionization coefficients for argon in a micro-discharge

    International Nuclear Information System (INIS)

    Ionization coefficients are measured for electrons in a dc micro-discharge in argon from optical emission profiles. The micro-discharge is operated in the Townsend regime between two parallel-plate electrodes. Axial profiles of emission are obtained with sufficient resolution to provide spatial ionization coefficients. The measured coefficients agree very well with the data obtained from other sources, indicating the operation of the discharge in the Townsend regime and also that Townsend mechanisms do not need extension to describe such discharges. (paper)

  13. Ionization coefficients for argon in a micro-discharge

    Science.gov (United States)

    Kuschel, Thomas; Stefanović, Ilija; Malović, Gordana; Marić, Dragana; Petrović, Zoran Lj

    2013-08-01

    Ionization coefficients are measured for electrons in a dc micro-discharge in argon from optical emission profiles. The micro-discharge is operated in the Townsend regime between two parallel-plate electrodes. Axial profiles of emission are obtained with sufficient resolution to provide spatial ionization coefficients. The measured coefficients agree very well with the data obtained from other sources, indicating the operation of the discharge in the Townsend regime and also that Townsend mechanisms do not need extension to describe such discharges.

  14. Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale

    CERN Document Server

    Lane, Charles D

    2016-01-01

    The notion of uniform and/or constant tensor fields of rank $>0$ is incompatible with general curved spacetimes. This work considers the consequences of certain tensor-valued coefficients for Lorentz violation in the Standard-Model Extension varying with spacetime position. We focus on two of the coefficients, $a_\\mu$ and $b_\\mu$, that characterize Lorentz violation in massive fermions, particularly in those fermions that constitute ordinary matter. We calculate the nonrelativistic hamiltonian describing these effects, and use it to extract the sensitivity of several precision experiments to coefficient variation.

  15. Determination of BEACON Coupling Coefficients using data from Xenon transient

    International Nuclear Information System (INIS)

    NEK uses BEACOTM code (BEACOTM - Westinghouse Best Estimate Analyzer for Core Operating Nuclear) for core monitoring, analysis and core behaviour prediction. Coupling Coefficients determine relationship between core response and excore instrumentation. Measured power distribution using incore moveable detectors during Xenon transient with sufficient power axial offset change is the most important data for further analysis. Classic methodology and BEACOTM Conservative methodology using established Coupling Coefficients are compared on NPP Krsko case. BEACONTM Conservative methodology with predefined Coupling Coefficients is used as a surveillance tool for verification of relationship between core and excore instrumentation during power operation. (author)

  16. Network clustering coefficient without degree-correlation biases.

    Science.gov (United States)

    Soffer, Sara Nadiv; Vázquez, Alexei

    2005-05-01

    The clustering coefficient quantifies how well connected are the neighbors of a vertex in a graph. In real networks it decreases with the vertex degree, which has been taken as a signature of the network hierarchical structure. Here we show that this signature of hierarchical structure is a consequence of degree-correlation biases in the clustering coefficient definition. We introduce a definition in which the degree-correlation biases are filtered out, and provide evidence that in real networks the clustering coefficient is constant or decays logarithmically with vertex degree.

  17. Bayesian Inference of Empirical Coefficient for Foundation Settlement

    Institute of Scientific and Technical Information of China (English)

    LI Zhen-yu; WANG Yong-he; YANG Guo-lin

    2009-01-01

    A new approach based on Bayesian theory is proposed to determine the empirical coefficient in soil settlement calculation. Prior distribution is assumed to be uniform in [0.2,1.4]. Posterior density function is developed in the condition of prior distribution combined with the information of observed samples at four locations on a passenger dedicated line. The results show that the posterior distribution of the empirical coefficient obeys Gaussian distribution. The mean value of the empirical coefficient decreases gradually with the increasing of the load on ground, and variance variation shows no regularity.

  18. Drag and lift coefficients evolution of a Savonius rotor

    Science.gov (United States)

    Chauvin, A.; Benghrib, D.

    1989-10-01

    The lift and drag coefficients of the rotating Savonius wind machine are determined from the pressure difference measured between the upper plane and the lower plane of a blade. Pressure measurements have been performed for two sets of experiments; the first one for U ∞ = 10 m/s and the second one for U ∞ = 12.5 m/s. In each case it is to be noted that a negative lift effect is present for low values of the tip speed ratio λ. The lift coefficient becomes positive when λ increases. The drag coefficient is of course always negative.

  19. Measurement of friction coefficient in aluminum sheet warm forming

    Institute of Scientific and Technical Information of China (English)

    GUO Zheng-hua; LI Zhi-gang; HUANG Chong-jiu; DONG Xiang-huai

    2005-01-01

    Aluminum alloy sheets are used more and more to manufacture auto panels. Because the friction behavior is very complicated, it is necessary to study the friction during the aluminum sheet warm forming process. The author has designed a new probe sensor based on an online tribotest method which directly measures friction coefficient in the forming process. Experiments of cup drawing have been conducted and the friction coefficients under different forming conditions have been measured. The results indicate that the forming parameters, such as forming temperature, blankholding force and lubrication status have great effect upon the friction coefficient.

  20. Adaptive Peak Frequency Estimation Using a Database of PARCOR Coefficients

    Directory of Open Access Journals (Sweden)

    Iiguni Youji

    2005-01-01

    Full Text Available This paper presents an adaptive peak frequency estimation method using a database that stores PARCOR coefficients as key attributes and the corresponding peak frequencies as nonkey attributes. The least-square lattice algorithm is used to recursively estimate the PARCOR coefficients to adapt to changing circumstances. The nearest neighbor to the current PARCOR coefficient is retrieved from the database, and the corresponding peak frequency is regarded as the estimation. A simultaneous execution of database construction and peak estimation with database update is performed to accelerate the processing time and to improve the estimation accuracy.

  1. Gamma-ray attenuation coefficients in bismuth borate glasses

    International Nuclear Information System (INIS)

    Mass attenuation coefficients of glasses in the system: xBi2O3(1-x)B2O3 (x=0.30, 0.35, 0.40, 0.45 and 0.55) were determined at 356, 662, 1173 and 1332 keV photon energies using a narrow beam transmission method. Appreciable variations were observed in these coefficients due to changes in the chemical composition of glasses. These coefficients were then used to determine effective atomic numbers of glass samples, which were found to be constant with bismuth concentration and energy

  2. Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient

    Directory of Open Access Journals (Sweden)

    Zaiyue Yang

    2014-01-01

    Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.

  3. Fractional crystallization of iron meteorites: Constant versus changing partition coefficients

    Science.gov (United States)

    Jones, J. H.

    1994-01-01

    Analyses of magmatic iron meteorites, plotted on LogC(sub i) vs LogC(sub Ni) diagrams, often form linear arrays. Traditionally, this linearity has been ascribed to fractional crystallization under the assumption of constant partition coefficients (i.e., Rayleigh fractionation). Paradoxically, however, partition coefficients in the Fe-Ni-S-P system are decidedly not constant. This contribution provides a rationale for understanding how trends on LogC(sub i) vs LogC(sub Ni) diagrams can be linear, even when partition coefficients are changing rapidly.

  4. Orientation and velocity dependence of the nonequilibrium partition coefficient

    Science.gov (United States)

    Beatty, K. M.; Jackson, K. A.

    1995-01-01

    Monte Carlo simulations based on a Spin-1 Ising Model for binary alloys have been used to investigate the non-equilibrium partition coefficient (k(sub neq)) as a function of solid-liquid interface velocity and orientation. In simulations of Si with a second component k(sub neq) is greater in the [111] direction than the [100] direction in agreement with experimental results reported by Azlz et al. The simulated partition coefficient scales with the square of the step velocity divided by the diffusion coefficient of the secondary component in the liquid.

  5. Universal statistics of the scattering coefficient of chaotic microwave cavities.

    Science.gov (United States)

    Hemmady, Sameer; Zheng, Xing; Antonsen, Thomas M; Ott, Edward; Anlage, Steven M

    2005-05-01

    We consider the statistics of the scattering coefficient S of a chaotic microwave cavity coupled to a single port. We remove the nonuniversal effects of the coupling from the experimental S data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized scattering coefficient whose probability density function (PDF) is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We compare experimental PDFs of the normalized scattering coefficients with those obtained from random matrix theory (RMT), and find excellent agreement. The results apply to scattering measurements on any wave chaotic system.

  6. Calculation of power coefficient in CANFLEX-NU fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung Joo; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    Changes in power level affect reactivity due to its dependence on fuel and coolant temperatures. The power coefficient of reactivity is related to the fuel temperature coefficient through the change in fuel temperature per percent change in power. In addition, power level changes are followed by changes in coolant temperature and density which contribute to the reactivity effect. In this report, the power coefficient of CANFLEX-NU was calculated and the result would be compared with that of CANDU-6 reactor which is operating. 8 refs., 43 figs., 2 tabs. (Author)

  7. Comparison of activity coefficient models for electrolyte systems

    DEFF Research Database (Denmark)

    Lin, Yi; ten Kate, Antoon; Mooijer, Miranda;

    2010-01-01

    Three activity coefficient models for electrolyte solutions were evaluated and compared. The activity coefficient models are: The electrolyte NRTL model (ElecNRTL) by Aspentech, the mixed solvent electrolyte model (MSE) by OLI Systems Inc., and the Extended UNIQUAC model from the Technical...... University of Denmark (DTU). Test systems containing a single salt (NaCl), multiple salts, and mixed solvent aqueous electrolyte solutions were chosen. The performance of the activity coefficient models were compared regarding the accuracy of solid-liquid and vapor-liquid equilibrium calculations...

  8. Steganography using Coefficient Replacement and Adaptive Scaling based on DTCWT

    Directory of Open Access Journals (Sweden)

    N Sathisha

    2015-03-01

    Full Text Available Steganography is an authenticated technique for maintaining secrecy of embedded data. Steganography provides hardness of detecting the hidden data and has a potential capacity to hide the existence of confidential data. In this paper, we propose a novel steganography using coefficient replacement and adaptive scaling based on Dual Tree Complex Wavelet Transform (DTCWT technique. The DTCWT and LWT 2 is applied on cover image and payload respectively to convert spatial domain into transform domain. The HH sub band coefficients of cover image are replaced by the LL sub band coefficients of payload to generate intermediate stego object and the adaptive scaling factor is used to scale down intermediate stego object coefficient values to generate final stego object. The adaptive scaling factor is determined based on entropy of cover image. The security and the capacity of the proposed method are high compared to the existing algorithms.

  9. Design formulas of transmission coefficients for permeable breakwaters

    Directory of Open Access Journals (Sweden)

    Su-xiang ZHANG

    2015-10-01

    Full Text Available New empirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure (LCS, including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations (MBEs, and a new expression relating the friction coefficient to the relative submerged depth was also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

  10. Design formulas of transmission coefficients for permeable breakwaters

    Institute of Scientific and Technical Information of China (English)

    Su-xiang ZHANG; Xi LI

    2014-01-01

    Newempirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure (LCS), including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations (MBEs), and a new expression relating the friction coefficientαto the relative submerged depth tsRHwas also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

  11. Rate coefficients for N2(+)(v) dissociative recombination

    Science.gov (United States)

    Bates, D. R.; Mitchell, J. B. A.

    1991-09-01

    The data of Zipf (1980) on N2(+)(v) dissociative recombination are analyzed taking into account the fact that there is coupling due to reversible symmetrical resonance charge transfer, N2(+)(v) + N2(0) yields N2(+)(0) + N2(v). The vibrational deactivation in N2(+)(v)-Ne collisions is also considered. A reported experimental value of the vibrational deactivation coefficient is found to be much higher than can be reconciled with the results of Zipf and it is therefore rejected. The analysis shows that the recombination coefficient for N2(+)(0) is about 2.6 x 10 exp-7 cu cm/s at 300 K and that recombination coefficients for N2(+)(1) and N2(+)(2) are substantially smaller. It is concluded that these coefficients conflict with the dissociative recombination cross section vs energy curve obtained by the merged beam method.

  12. A New Adaptive Image Denoising Method Based on Neighboring Coefficients

    Science.gov (United States)

    Biswas, Mantosh; Om, Hari

    2016-03-01

    Many good techniques have been discussed for image denoising that include NeighShrink, improved adaptive wavelet denoising method based on neighboring coefficients (IAWDMBNC), improved wavelet shrinkage technique for image denoising (IWST), local adaptive wiener filter (LAWF), wavelet packet thresholding using median and wiener filters (WPTMWF), adaptive image denoising method based on thresholding (AIDMT). These techniques are based on local statistical description of the neighboring coefficients in a window. These methods however do not give good quality of the images since they cannot modify and remove too many small wavelet coefficients simultaneously due to the threshold. In this paper, a new image denoising method is proposed that shrinks the noisy coefficients using an adaptive threshold. Our method overcomes these drawbacks and it has better performance than the NeighShrink, IAWDMBNC, IWST, LAWF, WPTMWF, and AIDMT denoising methods.

  13. ON SOLUTIONS TO SINGULAR FRACTIONAL DIFFERENTIAL SYSTEMS WITH CONSTANT COEFFICIENTS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we consider solutions to singular fractional differential systems with constant coefficients involving Riemann-Liouville differential operator. At first, we study the solvability of the systems. Then we discuss the general solution to the system.

  14. Calculation of diffusion coefficients in air-metal thermal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cressault, Y; Gleizes, A [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France)

    2010-11-03

    This paper presents the combined diffusion coefficients of metal vapours (silver, copper and iron) in air thermal plasmas for temperatures ranging from 300 to 30 000 K. The theory used to calculate these coefficients is remembered and validated by comparison with the literature values in several cases such as Ar-He, Ar-Cu and N{sub 2}-O{sub 2} mixtures. The results are discussed showing the influences of the metal concentration, of the vapour nature and of the pressure. The results show rather similar behaviour for the three metals. The maximum values of the combined ordinary diffusion coefficient in the evolution with temperature are obtained for temperature around 10 000 K but this peak is shifted to the highest temperatures when the metal proportion increases. Another result shows that the diffusion coefficient decreases when pressure increases.

  15. Multivalued Stochastic Differential Equations with Non-Lipschitz Coefficients

    Institute of Scientific and Technical Information of China (English)

    Siyan XU

    2009-01-01

    The existence and uniqueness of solutions to the multivalued stochastic differ-ential equations with non-Lipschitz coefficients are proved, and bicontinuons modifications of the solutions are obtained.

  16. Correlation coefficients and the Robertson-Schroedinger uncertainty relations

    CERN Document Server

    Fleming, G N

    2007-01-01

    Calling the quantity; 2delta(A)delta(B)/||, with non-zero denominator, the uncertainty product ratio or UPR for the pair of observables, (A, B), it is shown that any non-zero correlation coefficient between two observables raises, above unity, the lower bound of the UPR for each member of an infinite collection of pairs of incompatible observables. Conversely, any UPR is subject to lower bounds above unity determined by each of an infinite collection of correlation coefficients. This result generalizes the well known Schroedinger strengthening of the Robertson uncertainty relations (with the former expressed in terms of the correlation coefficient rather than the anticommutator) where the UPR and the correlation coefficient both involve the same pair of observables. Two, independent, derivations of the result are presented to clarify its origins and some examples of its use are examined.

  17. Einstein's coefficients and the nature of thermal radio emission

    OpenAIRE

    Prigara, F. V.

    2001-01-01

    The relations between Einstein's coefficients for spontaneous and induced emission of radiation with account for the natural linewidth are obtained . It is shown that thermal radio emission is stimulated one . Thermal radio emission of non-uniform gas is considered .

  18. Research on the Fault Coefficient in Complex Electrical Engineering

    Directory of Open Access Journals (Sweden)

    Yi Sun

    2015-08-01

    Full Text Available Fault detection and isolation in a complex system are research hotspots and frontier problems in the reliability engineering field. Fault identification can be regarded as a procedure of excavating key characteristics from massive failure data, then classifying and identifying fault samples. In this paper, based on the fundamental of feature extraction about the fault coefficient, we will discuss the fault coefficient feature in complex electrical engineering in detail. For general fault types in a complex power system, even if there is a strong white Gaussian stochastic interference, the fault coefficient feature is still accurate and reliable. The results about comparative analysis of noise influence will also demonstrate the strong anti-interference ability and great redundancy of the fault coefficient feature in complex electrical engineering.

  19. Verifying reciprocal relations for experimental diffusion coefficients in multicomponent mixtures

    DEFF Research Database (Denmark)

    Medvedev, Oleg; Shapiro, Alexander

    2003-01-01

    The goal of the present study is to verify the agreement of the available data on diffusion in ternary mixtures with the theoretical requirement of linear non-equilibrium thermodynamics consisting in symmetry of the matrix of the phenomenological coefficients. A common set of measured diffusion...... coefficients for a three-component mixture consists of four Fickian diffusion coefficients, each being reported separately. However, the Onsager theory predicts the existence of only three independent coefficients, as one of them disappears due to the symmetry requirement. Re-calculation of the Fickian...... extended sets of experimental data and reliable thermodynamic models were available. The sensitivity of the symmetry property to different thermodynamic parameters of the models was also checked. (C) 2003 Elsevier Science B.V. All rights reserved....

  20. Heat unit-based crop coefficient for grapefruit trees

    International Nuclear Information System (INIS)

    The onset and rate of sap moving up the branches of grapefruit (Citrus paradisi Macfadyen) trees were monitored hourly using portable sap flow sensors at Waddell, Arizona. Hourly reference evapotranspiration (ETo) estimates were calculated using data from a nearby weather station. Crop water use was estimated from soil moisture measurements using a neutron probe. These data were used to first delineate the upper and lower temperature threshold values for the determination of heat units. A heat unit-based crop coefficient was then derived from a correlation of the crop coefficient with heat units over a crop year. The heat unit-based crop coefficient was found to be similar to crop coefficients derived by other reseachers

  1. Approximate equations at breaking for nearshore wave transformation coefficients

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; SanilKumar, V.

    Based on small amplitude wave theory approximate equations are evaluated for determining the coefficients of shoaling, refraction, bottom friction, bottom percolation and viscous dissipation at breaking. The results obtainEd. by these equations...

  2. Lower bound of assortativity coefficient in scale-free networks

    CERN Document Server

    Yang, Dan; Zhou, Tao

    2016-01-01

    The degree-degree correlation is important in understanding the structural organization of a network and the dynamics upon a network. Such correlation is usually measured by the assortativity coefficient $r$, with natural bounds $r \\in [-1,1]$. For scale-free networks with power-law degree distribution $p(k) \\sim k^{-\\gamma}$, we analytically obtain the lower bound of assortativity coefficient in the limit of large network size, which is not -1 but dependent on the power-law exponent $\\gamma$. This work challenges the validation of assortativity coefficient in heterogeneous networks, suggesting that one cannot judge whether a network is positively or negatively correlated just by looking at its assortativity coefficient.

  3. On cloud modelling and the mass accommodation coefficient of water

    Directory of Open Access Journals (Sweden)

    A. Laaksonen

    2004-11-01

    Full Text Available The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04–1. From the viewpoint of cloud modelling, this is an unfortunate situation, since the value of the mass accommodation coefficient affects the model results, e.g. the number concentration of activated cloud droplets. In this paper we argue that a mass accommodation coefficient of unity should be used in cloud modelling, since this value has been obtained in experimental studies of water droplet growth rates, a quantity which is explicitly described in cloud models. In contrast, mass accommodation coefficient values below unity have been derived from experimental results which are analyzed with different theoretical expressions than those included in cloud models.

  4. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Science.gov (United States)

    Jalali, Majid; Mohammadi, Ali

    2008-05-01

    The compounds Na 2B 4O 7, H 3BO 3, CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  5. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    International Nuclear Information System (INIS)

    The compounds Na2B4O7, H3BO3, CdCl2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H3BO3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds

  6. Photothermal determination of optical coefficients using an optical fibre sensor

    CERN Document Server

    Laufer, J

    2000-01-01

    configuration is more sensitive to the thermal coefficients than the optical coefficients of the target. Pulsed photothermal radiometry was found to have higher sensitivity to the optical coefficients than has the optical fibre sensor in its present form. However, modifications to the configuration of the sensor can produce a performance matching that of pulsed photothermal radiometry. This thesis is concerned with the development of an optical fibre sensor for the photothermal determination of the optical coefficients of tissue. The detection of differences in tissue optical properties might be used for the diagnosis of cancers and other tissue pathologies. The sensor consists of a thin transparent polymer film mounted at the distal end of an optical fibre. The film acts as a Fabry-Perot interferometer. The absorption of short, low energy laser pulses transmitted through the film and into the tissue generates thermal as well as acoustic transients, which propagate into/the film and modulate its thickness. Th...

  7. The Influence of Carburizing Parameters on Carbon Transfer Coefficient

    Institute of Scientific and Technical Information of China (English)

    Tadeusz Sobusiak

    2004-01-01

    Definition of coefficient of carbon transfer in European Standard (EN 10052) is presented as: "Mass of carbon transferred from carburizing medium into the steel, per unit surface area per second for a unit difference between the carbon potential, and actual surface carbon content".In this paper, a model is presented of carbon transfer from endothermic atmospheres to carbon steel. The carbon transfer coefficient values were determined experimentally by the foil technique and on specimens, taking into account the following parameters: chemical composition of atmospheres, carbon potential, temperature and time of the carburizing process. Some examples of the variation of the carbon transfer coefficient for two steps of the carburizing process,including soaking before quenching, are given, based on results obtained. The effect of carbon transfer coefficient on carbon content at the steel surface is given.

  8. Seal assembly for materials with different coefficients of thermal expansion

    Science.gov (United States)

    Minford, Eric

    2009-09-01

    Seal assembly comprising (a) two or more seal elements, each element having having a coefficient of thermal expansion; and (b) a clamping element having a first segment, a second segment, and a connecting segment between and attached to the first and second segments, wherein the two or more seal elements are disposed between the first and second segments of the clamping element. The connecting segment has a central portion extending between the first segment of the clamping element and the second segment of the clamping element, and the connecting segment is made of a material having a coefficient of thermal expansion. The coefficient of thermal expansion of the material of the connecting segment is intermediate the largest and smallest of the coefficients of thermal expansion of the materials of the two or more seal elements.

  9. Determination of thermal diffusion coefficient of nanofluid: Fullerene-toluene

    Science.gov (United States)

    Martin, Alain; Bou-Ali, M. Mounir

    2011-05-01

    Thermodiffusion coefficient at fullerene mass concentrations of 0.05%, 0.1%, 0.15%, and 0.2% was established for pure fullerene (C 60) diluted in toluene solutions. For this, the thermogravitational technique has been used in planar configuration with 4 extraction points. The determination of the concentration distribution along the column in steady state is determined by the method of analysis based on density measurements. In order to determine the thermal diffusion coefficient all thermophysical properties such as density, viscosity, thermal expansion coefficient and mass expansion coefficients were determined. All these studies coincide with the importance of the knowledge of the thermophysics and transport properties of the nanofluids to develop new applications and to optimize the existing ones.

  10. Temperature dependence of the Soret coefficient of ionic colloids

    Science.gov (United States)

    Sehnem, A. L.; Figueiredo Neto, A. M.; Aquino, R.; Campos, A. F. C.; Tourinho, F. A.; Depeyrot, J.

    2015-10-01

    The temperature dependence of the Soret coefficient ST(T ) in electrostatically charged magnetic colloids is investigated. Two different ferrofluids, with different particles' mean dimensions, are studied. In both cases we obtain a thermophilic behavior of the Soret effect. The temperature dependence of the Soret coefficient is described assuming that the nanoparticles migrate along the ionic thermoelectric field created by the thermal gradient. A model based on the contributions from the thermoelectrophoresis and variation of the double-layer energy, without fitting parameters, is used to describe the experimental results of the colloid with the bigger particles. To do so, independent measurements of the ζ potential, mass diffusion coefficient, and Seebeck coefficient are performed. The agreement of the theory and the experimental results is rather good. In the case of the ferrofluid with smaller particles, it is not possible to get experimentally reliable values of the ζ potential and the model described is used to evaluate this parameter and its temperature dependence.

  11. A Comparison of Composite Reliability Estimators: Coefficient Omega Confidence Intervals in the Current Literature

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2016-01-01

    Coefficient omega and alpha are both measures of the composite reliability for a set of items. Unlike coefficient alpha, coefficient omega remains unbiased with congeneric items with uncorrelated errors. Despite this ability, coefficient omega is not as widely used and cited in the literature as coefficient alpha. Reasons for coefficient omega's…

  12. ON THE COEFFICIENTS OF A POLYNOMIAL WITH RESTRICTED ZEROS

    Institute of Scientific and Technical Information of China (English)

    A.Aziz; W.M.Shah

    2009-01-01

    LetP(Z)=αn Zn + αn-1Zn-1 +…+α0 be a complex polynomial of degree n. There is a close connection between the coefficients and the zeros of P(z). In this paper we prove some sharp inequalities concerning the coeffi-cients of the polynomial P(z) with restricted zeros. We also establish a sufficient condition for the separation of zeros of P(z).

  13. Acoustic Emotion Recognition Using Linear and Nonlinear Cepstral Coefficients

    OpenAIRE

    Farah Chenchah; Zied Lachiri

    2015-01-01

    Recognizing human emotions through vocal channel has gained increased attention recently. In this paper, we study how used features, and classifiers impact recognition accuracy of emotions present in speech. Four emotional states are considered for classification of emotions from speech in this work. For this aim, features are extracted from audio characteristics of emotional speech using Linear Frequency Cepstral Coefficients (LFCC) and Mel-Frequency Cepstral Coefficients (MFCC). Further, th...

  14. Phase determination of x-ray reflection coefficients

    International Nuclear Information System (INIS)

    It is shown to what extent the phase of a reflection coefficient may be determined from a single x-ray reflectivity experiment. Complex calculus guarantees that the so-called 'phase problem' is relaxed for certain situations and the reflection coefficient is only determined by its moduls. A procedure to reconstruct the phase from a single measurement under incorporation of preknowledge of the system is derived and tested by numerical examples

  15. New approach to exact extraction of piezoresistance coefficient

    OpenAIRE

    Gniazdowski, Zenon; Latecki, Bogdan; Kowalski, Pawel

    2016-01-01

    The extension of piezoresistance coefficient extraction method was proposed, for protection from errors in estimation of the thickness of the test structure membrane. This new approach requires finding models of elements of matrix of integrated stresses as functions of the membrane thickness. Additionally, two test structures with different thickness of the membrane have to be used. This improved method gives the more credible estimation of piezoresistance coefficients $\\pi_L$ and $\\pi_T$ and...

  16. Experimental Excitation Rate Coefficients for Ne VIII Ions

    Science.gov (United States)

    Chang, C. C.; Greve, P.; Kolk, K.-H.; Kunze, H.-J.

    1984-02-01

    From the line emission of a pure neon plasma produced in a theta pinch discharge rate coefficients for the excitation of the n = 3 and 4 levels in Ne VIII ions are derived and compared with theoretical calculations and previous measurements. The general agreement between theory and all measurements is rather satisfactory for the excitation to the n = 3 levels, the measured rate coefficients to the 4p and 4d levels, however, being consistently too low.

  17. Analytical computation of reflection and transmission coefficients for love waves

    International Nuclear Information System (INIS)

    The computation of the transmission and reflection coefficients is an important step in the construction, if modal summation technique is used, of synthetic seismograms for 2-D or 3-D media. These coupling coefficients for Love waves at a vertical discontinuity are computed analytically. Numerical test for realistic structures show how the energy carried by an incoming mode is redistributed on the various modes existing on both sides of the vertical interface. (author). 15 refs, 8 figs

  18. Scaling the Raman Gain Coefficient of Optical Fibers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Bromage, J; Leng, L

    2002-01-01

    Scaling rules for the Raman gain coefficient are provided with emphasis on the effective area and wavelength dependence. Translation from measurements made at one pump wavelength to other pump wavelengths is demonstrated.......Scaling rules for the Raman gain coefficient are provided with emphasis on the effective area and wavelength dependence. Translation from measurements made at one pump wavelength to other pump wavelengths is demonstrated....

  19. Age-dependent dose coefficients for tritium in Asian populations

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, A

    1999-10-01

    The International Commission on Radiological Protection (ICRP) Publications 56 (1989) and 67 (1993) have prescribed the biokinetic models and age-dependent dose coefficients for tritiated water and organically bound tritium. The dose coefficients are computed from values selected to specify the anatomical, morphological and physiological characteristics of a three-month-old, one-year-old, five-year-old, 10-year-old, 15-year-old and adult (Reference Man) Caucasian living in North America and Western Europe. However, values for Reference Man and other age groups are not directly applicable to Asians, because of differences in race, custom, dietary habits and climatic conditions. An Asian Man model, including five age groups, has been proposed by Tanaka and Kawamura (1996, 1998) for use in internal dosimetry. The basic concept of the ICRP Reference Man and the system describing body composition in ICRP Publication 23 (1975) were used. Reference values for Asians were given for the body weight and height, the mass of soft tissue, the mass of body water and the daily fluid balance, and are used to compute the dose coefficients for tritium. The age-dependent dose coefficients for Asians for tritiated water intakes are smaller by 20 to 30% of the currently prescribed values (Trivedi, 1998). The reduction in the dose coefficient values is caused by the increased daily fluid balance among Asians. The dose coefficient for tritiated water is 1.4 x 10{sup -11} Sv Bq{sup -1} for Asian Man compared to 2.0 x 10{sup -11} Sv Bq{sup -1} for Reference Man. The dose coefficients for organically bound tritium are only marginally different from those of the ICRP values. The dose coefficient for organically bound tritium for Asian Man is 4.0 x 10{sup -11} Sv Bq{sup -11} compared to 4.6 x 10{sup -11} Sv Bq{sup -1} for Reference Man. (author)

  20. Transport coefficients for driven granular mixtures at low-density

    OpenAIRE

    Khalil, Nagi; Garzó, Vicente

    2013-01-01

    The transport coefficients of a granular binary mixture driven by a stochastic bath with friction are determined from the inelastic Boltzmann kinetic equation. A normal solution is obtained via the Chapman-Enskog method for states near homogeneous steady states. The mass, momentum, and heat fluxes are determined to first order in the spatial gradients of the hydrodynamic fields, and the associated transport coefficients are identified. They are given in terms of the solutions of a set of coup...

  1. Measurement of carbon dioxide diffusion coefficient of concrete

    OpenAIRE

    Villain, G.; PAVOINE, A; Thiery, M.

    2006-01-01

    The carbonation of concrete is a chemical reaction, which can be at the origin of the premature degradation of reinforced concrete structures. In order to predict service life of reinforced concrete structures, many models based on gas diffusion were developed. The carbon dioxide diffusion coefficient of concrete is thus a significant input datum for these models. The objective of this article is to present a simple reliable testing method to quantify the carbon dioxide diffusion coefficient ...

  2. Calculation of self-diffusion coefficients in iron

    OpenAIRE

    Baohua Zhang

    2014-01-01

    On the basis of available P-V-T equation of state of iron, the temperature and pressure dependence of self-diffusion coefficients in iron polymorphs (α, δ, γ and ɛ phases) have been successfully reproduced in terms of the bulk elastic and expansivity data by means of a thermodynamical model that interconnects point defects parameters with bulk properties. The calculated diffusion parameters, such as self-diffusion coefficient, activation energy and activation volume over a broad temperature r...

  3. The temperature variation of hydrogen diffusion coefficients in metal alloys

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    Hydrogen diffusion coefficients were measured as a function of temperature for a few metal alloys using an electrochemical evolution technique. Results from these measurements are compared to those obtained by the time-lag method. In all cases, diffusion coefficients obtained by the electrochemical method are larger than those by the time-lag method by an order of magnitude or more. These differences are attributed mainly to hydrogen trapping.

  4. On the significance level of the multirelation coefficient

    OpenAIRE

    Zvi Drezner; Roger Dear

    1997-01-01

    The concept of the multirelation coefficient is defined to describe the closeness of a set of variables to a linear relation. This concept extends the linear correlation between two variables to two or more variables. Parameters of a beta distribution are determined that are utilized to approximate significance levels of the multirelation coefficient for any given number of observations and variables. A generalized Student t distribution is defined. This distribution, which is termed the mult...

  5. Coefficient strengthening : a tool for formulating mixed integer programs

    OpenAIRE

    Andersen, Kent; Pochet, Yves

    2007-01-01

    Providing a good formulation is an important part of solving a mixed integer program. We suggest to measure the quality of a formulation by whether it is possible to strengthen the coefficients of the formulation. Sequentially strengthening coefficients can then be used as a tool for improving formulations. We believe this method could be useful for analyzing and producing tight formulations of problems that arise in practice. We illustrate the use of the approach on a problem in production s...

  6. Determination of mutual diffusion coefficients in quaternary alloy systems

    International Nuclear Information System (INIS)

    Procedures of experimental study of mutual diffusion in four-component system are developed, limit ratios for diffusion coefficients are found at the transition from four component system to three-component one and experimental check of some of these ratios is carried out. Concentrational dependence of complete matrix of outer diffusion coefficients in Fe-Cr-Ni-Co system is determined. Limit correlations for this system are checked up at cobalt concentration yielding to zero

  7. Black holes, information, and the universal coefficient theorem

    Science.gov (United States)

    Patrascu, Andrei T.

    2016-07-01

    General relativity is based on the diffeomorphism covariant formulation of the laws of physics while quantum mechanics is based on the principle of unitary evolution. In this article, I provide a possible answer to the black hole information paradox by means of homological algebra and pairings generated by the universal coefficient theorem. The unitarity of processes involving black holes is restored by the demanding invariance of the laws of physics to the change of coefficient structures in cohomology.

  8. Determining Absorption, Emissivity Reduction, and Local Suppression Coefficients inside Sunspots

    OpenAIRE

    Ilonidis, Stathis; Zhao, Junwei

    2010-01-01

    The power of solar acoustic waves is reduced inside sunspots mainly due to absorption, emissivity reduction, and local suppression. The coefficients of these power-reduction mechanisms can be determined by comparing time-distance cross-covariances obtained from sunspots and from the quiet Sun. By analyzing 47 active regions observed by SOHO/MDI without using signal filters, we have determined the coefficients of surface absorption, deep absorption, emissivity reduction, and local suppression....

  9. A Generalized Definition of the Polychoric Correlation Coefficient

    OpenAIRE

    Ekström, Joakim

    2011-01-01

    The polychoric correlation coefficient is a measure of association for ordinal variables which rests upon an assumption of an underlying joint continuous distribution. More specifically, in Karl Pearson’s original definition an underlying joint normal distribution is assumed. In this article, the definition of the polychoric correlation coefficient is generalized so that it allows for other distributional assumptions than the joint normal distribution. The generalized definition is analogous ...

  10. Calculating rotordynamic coefficients of seals by finite-difference techniques

    Science.gov (United States)

    Dietzen, F. J.; Nordmann, R.

    1987-01-01

    For modelling the turbulent flow in a seal the Navier-Stokes equations in connection with a turbulence (kappa-epsilon) model are solved by a finite-difference method. A motion of the shaft round the centered position is assumed. After calculating the corresponding flow field and the pressure distribution, the rotor-dynamic coefficients of the seal can be determined. These coefficients are compared with results obtained by using the bulk flow theory of Childs and with experimental results.

  11. Coefficient of variation calculated from the range for skewed distributions.

    Science.gov (United States)

    Rhiel, G Steven

    2006-02-01

    In this research a coefficient of variation (CVS(high.low)) is developed that is calculated from the highest and lowest values in a set of data for samples from skewed distributions. A correction factor is determined such that CVS(high-low) is a dose estimate of the population coefficient of variation when sampling from three skewed chi-squared distributions and three skewed empirical distributions. The empirical distributions are from "real-world" data sets in psychology and education.

  12. Coefficient of variation and Power Pen's parade computation

    OpenAIRE

    Sadefo Kamdem, Jules

    2011-01-01

    Under the the assumption that income y is a power function of its rank among n individuals, we approximate the coefficient of variation and gini index as functions of the power degree of the Pen's parade. Reciprocally, for a given coefficient of variation or gini index, we propose the analytic expression of the degree of the power Pen's parade; we can then compute the Pen's parade.

  13. Spatial variation of the longitudinal dispersion coefficient in an estuary

    OpenAIRE

    D. C. Shaha; Y.-K. Cho; M.-T. Kwak; S. R. Kundu; K. T. Jung

    2011-01-01

    The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tide is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal vari...

  14. Experimental investigation of drag coefficients of gobi surfaces

    Institute of Scientific and Technical Information of China (English)

    董治宝; 屈建军; 刘小平; 张伟民; 王训明

    2002-01-01

    The response of gobi surfaces to the near-surface air flow can be characterized quantitatively by drag coefficients. By using wind tunnel tests, an attempt is made to define the relationship between the drag coefficients of gobi surfaces and gravel size and coverage. It is concluded that the drag coefficients of gobi surfaces tend to be constants when gravel coverage is over 40%-50%. Consequently, we think that the gobi deflation planes expanding vastly in the arid Northwestern China are aerodynamically stable, at least not the supplying sources of current dust storms, and therefore the emphasis on dust storm control should be paid on the so-called "earth gobi" that has low gravel coverage. The prediction model for drag coefficients of gobi surfaces has been developed by regressing drag coefficients on gravel size and coverage, the predicted results are in reasonably good agreement with wind tunnel results (R 2 = 0.94). The change of drag coefficients with gravel friction Reynolds number implies that the development extent of drag effect increases with gravel size and coverage.

  15. Non intrusive measurement of the convective heat transfer coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Rebay, M.; Mebarki, G.; Padet, J. [Reims Univ., Reims (France). Faculty of Science, GRESPI Thermomechanical Lab; Arfaoui, A. [Reims Univ., Reims (France). Faculty of Science, GRESPI Thermomechanical Lab; Tunis Univ., Tunis (Tunisia). Faculty of Science, EL MANAR, LETTM; Maad, B.R. [Tunis Univ., Tunis (Tunisia). Faculty of Science, EL MANAR, LETTM

    2010-07-01

    The efficiency of cooling methods in thermal systems such as radiators and heat exchangers must be improved in order to enhance performance. The evaluation of the heat transfer coefficients between a solid and a fluid is necessary for the control and the dimensioning of thermal systems. In this study, the pulsed photothermal method was used to measure the convective heat transfer coefficient on a solid-fluid interface, notably between an air flow and a heated slab mounted on a PVC flat plate. This configuration simulated the electronic air-cooling inside enclosures and racks. The influence of the deflector's inclination angle on the enhancement of heat transfer was investigated using 2 newly developed identification models. The first model was based on a constant heat transfer coefficient during the pulsed experiment, while the second, improved model was based on a variable heat transfer coefficient. The heat transfer coefficient was deduced from the evolution of the transient temperature induced by a sudden deposit of a luminous energy on the front face of the slab. Temperature evolutions were derived by infrared thermography, a camera for cartography and a detector for precise measurement in specific locations. The results show the improvement of measurement accuracies when using a model that considers the temporal evolution of the convective heat transfer coefficient. The deflection of air flow on the upper surface of the heated slab demonstrated better cooling of the slab by the deflection of air flow. 11 refs., 1 tab., 8 figs.

  16. Study and verification on dispersion coefficient in wave field

    Institute of Scientific and Technical Information of China (English)

    SHEN LiangDuo; ZOU ZhiLi

    2012-01-01

    Transport and diffusion caused by coastal waves have different characteristics from those induced by flows.Through solving the vertical diffusion equation by an analytic method,this paper infers a theoretical formula of dispersion coefficient under the combined action of current and waves.It divides the general dispersion coefficient into six parts,including coefficients due to tidal current,Stokes drift,wave oscillation and interaction among them.It draws a conclusion that the contribution of dispersive effect induced by coastal waves is mainly produced by Stokes drift,while the contributions to time-averaged dispersion coefficient due to wave orbital motion and interaction between current and waves are very small.The results without tidal current are in agreement with the numerical and experimental results,which proves the correctness of the theoretical derivation.This paper introduces the variation characteristics of both the time-averaged and oscillating dispersion coefficients versus relative water depth,and demonstrates the physical implications of the oscillating mixing coefficient due to waves.We also apply the results to the costal vertical circulation and give its characteristics compared to Stokes drift.

  17. Determination of Heat Accumulation Coefficient for Oil Bonded Moulding Sands

    Directory of Open Access Journals (Sweden)

    M. Łągiewka

    2013-04-01

    Full Text Available The possibility of controlling the solidification and cooling time of castings creates prospects of improving their structure and by the same their properties. Thermal properties of the mould constitute therefore an important factor which is necessary to consider while seeking for the mentioned improvement. The presented work illustrates the method of determining some basic thermal coefficients of moulding material, i.e. the coefficient of temperature equalisation a2, known also as the temperature diffusivity, and the heat accumulation coefficient b2, which characterises the ability of moulding material to draw away the heat from a casting. The method consists in experimental determining the temperature field within the mould during the processes of pouring, solidification and cooling of the casting. The performed measurements allow for convenient and exact calculations of the sought-after coefficients. Examinations were performed for the oil bonded moulding sand of trade name OBB SAND ‘E’. The experiment showed that the obtained value of b2 coefficient differs from the value calculated on the basis of theoretical considerations available in publications. Therefore it can be stated that theoretical calculations of the heat accumulation coefficient are thus far not sufficient and not quite reliable, so that these calculations should be verified experimentally.

  18. Attenuation Coefficient Estimation of the Healthy Human Thyroid In Vivo

    Science.gov (United States)

    Rouyer, J.; Cueva, T.; Portal, A.; Yamamoto, T.; Lavarello, R.

    Previous studies have demonstrated that attenuation coefficients can be useful towards characterizing thyroid tissues. In this work, ultrasonic attenuation coefficients were estimated from healthy human thyroids in vivo using a clinical scanner. The selected subjects were five young, healthy volunteers (age: 26 ± 6 years old, gender: three females, two males) with no reported history of thyroid diseases, no palpable thyroid nodules, no smoking habits, and body mass index less than 30 kg/m2. Echographic examinations were conducted by a trained sonographer using a SonixTouch system (Ultrasonix Medical Corporation, Richmond, BC) equipped with an L14-5 linear transducer array (nominal center frequency of 10 MHz, transducer footprint of 3.8 cm). Radiofrequency data corresponding to the collected echographic images in both transverse and longitudinal views were digitized at a sampling rate of 40 MHz and processed with Matlab codes (MathWorks, Natick, MA) to estimate attenuation coefficients using the spectral log difference method. The estimation was performed using an analysis bandwidth spanning from 4.0 to 9.0 MHz. The average value of the estimated ultrasonic attenuation coefficients was equal to 1.34 ± 0.15 dB/(cm.MHz). The standard deviation of the estimated average attenuation coefficient across different volunteers suggests a non-negligible inter-subject variability in the ultrasonic attenuation coefficient of the human thyroid.

  19. Coefficients of Productivity for Yellowstone's Grizzly Bear Habitat

    Science.gov (United States)

    Mattson, David John; Barber, Kim; Maw, Ralene; Renkin, Roy

    2004-01-01

    This report describes methods for calculating coefficients used to depict habitat productivity for grizzly bears in the Yellowstone ecosystem. Calculations based on these coefficients are used in the Yellowstone Grizzly Bear Cumulative Effects Model to map the distribution of habitat productivity and account for the impacts of human facilities. The coefficients of habitat productivity incorporate detailed information that was collected over a 20-year period (1977-96) on the foraging behavior of Yellowstone's bears and include records of what bears were feeding on, when and where they fed, the extent of that feeding activity, and relative measures of the quantity consumed. The coefficients also incorporate information, collected primarily from 1986 to 1992, on the nutrient content of foods that were consumed, their digestibility, characteristic bite sizes, and the energy required to extract and handle each food. Coefficients were calculated for different time periods and different habitat types, specific to different parts of the Yellowstone ecosystem. Stratifications included four seasons of bear activity (spring, estrus, early hyperphagia, late hyperphagia), years when ungulate carrion and whitebark pine seed crops were abundant versus not, areas adjacent to (bear activity in each region, habitat type, and time period were incorporated into calculations, controlling for the effects of proximity to human facilities. The coefficients described in this report and associated estimates of grizzly bear habitat productivity are unique among many efforts to model the conditions of bear habitat because calculations include information on energetics derived from the observed behavior of radio-marked bears.

  20. Total dielectronic recombination rate coefficient for Co-like tungsten

    International Nuclear Information System (INIS)

    Ab initio calculation of the total dielectronic recombination (DR) rate coefficient from the ground state 3s23p63d9(J=5/2) of Co-like tungsten is performed employing the relativistic distorted-wave approximation with configuration-interaction. The DR contributions mainly come from complex series 3d84ln'l'. The complex series 3p53d10n'l', 3p53d94ln'l' and 3d85ln'l' also contribute significantly to the total DR rates at relatively high electron temperatures. The l' and n' dependences of the partial rate coefficient are investigated. The inclusion of decays into autoionizing levels followed by radiative cascades (DAC) enlarges the total DR rate coefficients by a factor of about 10%. The level-by-level extrapolation method is developed to include DAC effects. The total DR rate coefficients are fitted to an empirical formula. It is shown that at temperatures above 2.5 keV the Burgess-Merts (BM) semiempirical formula can provide DR results with an accuracy of about 15%, whereas at electron temperatures below 100 eV it underestimates the DR rate coefficients by up to a few orders of magnitude and its temperature dependence is completely inadequate. The comparison of the results for Ni-like and Co-like tungsten shows that these two sets of DR rate coefficients are very close in magnitude at relatively high electron temperatures

  1. Temperature dependence of Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal

    Science.gov (United States)

    Lu, Qieni; Han, Jinxin; Dai, Haitao; Ge, Baozhen; Zhao, Shuang

    2015-08-01

    We measure temperature dependence on Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal simultaneously in this work, based on digital holographic interferometry (DHI). And the spatial distribution of the field-induced refractive index change can also be visualized and estimated by numerically retrieving sequential phase maps of Mn:Fe:KTN crystal from recording digital holograms in different states. The refractive indices decrease with increasing temperature and quadratic polarized optical coefficient is insensitive to temperature. The experimental results suggest that the DHI method presented here is highly applicable in both visualizing the temporal and spatial behavior of the internal electric field and accurately measuring electro-optic coefficient for electrooptical media.

  2. Temperature dependence of Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal

    Directory of Open Access Journals (Sweden)

    Qieni Lu

    2015-08-01

    Full Text Available We measure temperature dependence on Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal simultaneously in this work, based on digital holographic interferometry (DHI. And the spatial distribution of the field-induced refractive index change can also be visualized and estimated by numerically retrieving sequential phase maps of Mn:Fe:KTN crystal from recording digital holograms in different states. The refractive indices decrease with increasing temperature and quadratic polarized optical coefficient is insensitive to temperature. The experimental results suggest that the DHI method presented here is highly applicable in both visualizing the temporal and spatial behavior of the internal electric field and accurately measuring electro-optic coefficient for electrooptical media.

  3. Similarity analysis between chromosomes of Homo sapiens and monkeys with correlation coefficient, rank correlation coefficient and cosine similarity measures

    OpenAIRE

    Chinta Someswara Rao; S. Viswanadha Raju

    2016-01-01

    In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship b...

  4. Generalized transport coefficients for inelastic Maxwell mixtures under shear flow.

    Science.gov (United States)

    Garzó, Vicente; Trizac, Emmanuel

    2015-11-01

    The Boltzmann equation framework for inelastic Maxwell models is considered to determine the transport coefficients associated with the mass, momentum, and heat fluxes of a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. The Boltzmann equation is solved by means of a Chapman-Enskog-type expansion around the (local) shear flow distributions f(r)(0) for each species that retain all the hydrodynamic orders in the shear rate. Due to the anisotropy induced by the shear flow, tensorial quantities are required to describe the transport processes instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled equations, which can be analytically solved as functions of the shear rate a, the coefficients of restitution α(rs), and the parameters of the mixture (masses, diameters, and composition). Since the reference distribution functions f(r)(0) apply for arbitrary values of the shear rate and are not restricted to weak dissipation, the corresponding generalized coefficients turn out to be nonlinear functions of both a and α(rs). The dependence of the relevant elements of the three diffusion tensors on both the shear rate and dissipation is illustrated in the tracer limit case, the results showing that the deviation of the generalized transport coefficients from their forms for vanishing shear rates is in general significant. A comparison with the previous results obtained analytically for inelastic hard spheres by using Grad's moment method is carried out, showing a good agreement over a wide range of values for the coefficients of restitution. Finally, as an application of the theoretical expressions derived here for the transport coefficients, thermal diffusion segregation of an intruder immersed in a granular gas is also studied. PMID:26651684

  5. Development of reflectance-based crop coefficients for corn

    International Nuclear Information System (INIS)

    Concurrent measurements of reflected canopy radiation and the basal crop coefficient (K^b) for corn were conducted throughout a season in order to develop a reflectance-based crop coefficient model. Reflectance was measured in Landsat Thematic Mapper bands TM3 (0.63 - 0.69 um) and TM4 (0.76 - 0.90 um) and used in the calculation of a vegetation index called the normalized difference (ND). A linear transformation of the ND was used as the reflectance-based crop coefficient (Kcr). The transformation equates the ND for dry bare soil and the ND at effective cover, to the basal crop coefficient for dry soil evaporation and at effective cover, respectively. Basal crop coefficient values for com were obtained from daily evapotranspiration measurements of corn and alfalfa, using hydraulic weighing lysimeters. The Richards growth curve function was fitted to both sets of data. The K^b values were determined to be within -2.6% and 4.7% of the K^^ values. The date of effective cover obtained from the K^b data was within four days of the date on which the ND curve reached its maxima according to the Richards function. A comparison of the Kcr with basal crop curves from the literature for several years of data indicated good agreement. Reflectance-based crop coefficients are sensitive to periods of slow and fast growth induced by weather conditions, resulting in a real time coefficient, independent from the traditional time base parameters based on the day of planting and effective cover

  6. Transition Operators

    CERN Document Server

    Alcock-Zeilinger, Judith

    2016-01-01

    In this paper, we give a generic algorithm of the transition operators between Hermitian Young projection operators corresponding to equivalent irreducible representations of SU(N), using the compact expressions of Hermitian Young projection operators derived in a companion paper. We show that the Hermitian Young projection operators together with their transition operators constitute a fully orthogonal basis for the algebra of invariants of $V^{\\otimes m}$ that exhibits a systematically simplified multiplication table. We discuss the full algebra of invariants over $V^{\\otimes 3}$ and $V^{\\otimes 4}$ as explicit examples. In our presentation we make use of various standard concepts such as Young projection operators, Clebsch-Gordan operators, and invariants (in birdtrack notation). We tie these perspectives together and use them to shed light on each other.

  7. Activity coefficients in nearly athermal model polymer/solvent systems

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Y.J.; Panagiotopoulos, A.Z. [Cornell Univ., Ithaca, NY (United States). School of Chemical Engineering; Tassios, D.P. [National Technical Univ. of Athens, Zographos (Greece). Dept. of Chemical Engineering

    1995-10-01

    Phase equilibria play a crucial role in the design of polymer manufacturing processes. Knowledge of the phase behavior of polymer/solvent solutions is especially important for polymer production and purification operations. Constant pressure Monte Carlo simulations were performed to study the activity coefficients of bead-spring polymers dissolved in a monomeric solvent. Activity coefficients were obtained for binary mixtures of monomer and 20-mer for compositions ranging from pure 20-mer to pure solvent, using the chain increment method to obtain the chemical potentials of long-chain solute and monomeric solvent. Infinite dilution activity coefficients were also calculated for polymeric solutes in monomeric solvents and monomeric solutes in polymeric solvents solutions with chain length up to 60. Such detailed information on activity coefficients in polymer/solvent systems with large size differences had not been available previously from simulation or experiment. Several engineering models were tested for their ability to predict the activity coefficients in these nearly a thermal systems. Results indicate that simple free-volume models can provide qualitatively accurate predictions for both short-chain solvent and long-chain solutes, provided that the functional form of the free-volume dependence is chosen appropriately.

  8. [Biodegradation Coefficients of Typical Pollutants in the Plain Rivers Network].

    Science.gov (United States)

    Feng, Shuai; Li, Xu-yongl; Deng, Jian-cai

    2016-05-15

    Biodegradation is a significant part of pollutant integrated degradation, the process rate of which is represented by the biodegradation coefficient. To investigate the biodegradation law of typical pollutants in the plain rivers network located in the upstream of the Lake Taihu, experiments were conducted in site in September 2015, one order kinetics model was used to measure the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus, and influencing factors of the biodegradation coefficients were also analyzed. The results showed that the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus were 0.008 3-0.126 4 d⁻¹, 0.002 1-0.213 8 d⁻¹, 0.002 1-0.090 5 d⁻¹ and 0.011 0- 0.152 8 d⁻¹, respectively. The influencing factors of the biodegradation coefficients for permanganate index were permanganate index and pH; those for ammonia were ammonia concentration and pH; those for total nitrogen were inorganic nitrogen concentration, total dissolved solid concentration and nitrite concentration; and those for total phosphorus were background concentration and pH. The research results were of important guiding significance for pollutants removal and ecological restoration of the plain rivers network located in the unstream of the Lake Taihu. PMID:27506025

  9. Viscosity Coefficient Curve Fits for Ionized Gas Species Grant Palmer

    Science.gov (United States)

    Palmer, Grant; Arnold, James O. (Technical Monitor)

    2001-01-01

    Viscosity coefficient curve fits for neutral gas species are available from many sources. Many do a good job of reproducing experimental and computational chemistry data. The curve fits are usually expressed as a function of temperature only. This is consistent with the governing equations used to derive an expression for the neutral species viscosity coefficient. Ionized species pose a more complicated problem. They are subject to electrostatic as well as intermolecular forces. The electrostatic forces are affected by a shielding phenomenon where electrons shield the electrostatic forces of positively charged ions beyond a certain distance. The viscosity coefficient for an ionized gas species is a function of both temperature and local electron number density. Currently available curve fits for ionized gas species, such as those presented by Gupta/Yos, are a function of temperature only. What they did was to assume an electron number density. The problem is that the electron number density they assumed was unrealistically high. The purpose of this paper is two-fold. First, the proper expression for determining the viscosity coefficient of an ionized species as a function of both temperature and electron number density will be presented. Then curve fit coefficients will be developed using the more realistic assumption of an equilibrium electron number density. The results will be compared against previous curve fits and against highly accurate computational chemistry data.

  10. Identifying Bearing Rotodynamic Coefficients Using an Extended Kalman Filter

    Science.gov (United States)

    Miller, Brad A.; Howard, Samuel A.

    2008-01-01

    An Extended Kalman Filter is developed to estimate the linearized direct and indirect stiffness and damping force coefficients for bearings in rotor dynamic applications from noisy measurements of the shaft displacement in response to imbalance and impact excitation. The bearing properties are modeled as stochastic random variables using a Gauss-Markov model. Noise terms are introduced into the system model to account for all of the estimation error, including modeling errors and uncertainties and the propagation of measurement errors into the parameter estimates. The system model contains two user-defined parameters that can be tuned to improve the filter's performance; these parameters correspond to the covariance of the system and measurement noise variables. The filter is also strongly influenced by the initial values of the states and the error covariance matrix. The filter is demonstrated using numerically simulated data for a rotor bearing system with two identical bearings, which reduces the number of unknown linear dynamic coefficients to eight. The filter estimates for the direct damping coefficients and all four stiffness coefficients correlated well with actual values, whereas the estimates for the cross-coupled damping coefficients were the least accurate.

  11. Identifying Bearing Rotordynamic Coefficients using an Extended Kalman Filter

    Science.gov (United States)

    Miller, Bard A.; Howard, Samuel A.

    2008-01-01

    An Extended Kalman Filter is developed to estimate the linearized direct and indirect stiffness and damping force coefficients for bearings in rotor-dynamic applications from noisy measurements of the shaft displacement in response to imbalance and impact excitation. The bearing properties are modeled as stochastic random variables using a Gauss-Markov model. Noise terms are introduced into the system model to account for all of the estimation error, including modeling errors and uncertainties and the propagation of measurement errors into the parameter estimates. The system model contains two user-defined parameters that can be tuned to improve the filter s performance; these parameters correspond to the covariance of the system and measurement noise variables. The filter is also strongly influenced by the initial values of the states and the error covariance matrix. The filter is demonstrated using numerically simulated data for a rotor-bearing system with two identical bearings, which reduces the number of unknown linear dynamic coefficients to eight. The filter estimates for the direct damping coefficients and all four stiffness coefficients correlated well with actual values, whereas the estimates for the cross-coupled damping coefficients were the least accurate.

  12. Experimental determination of the lineal attenuation coefficient of ground

    International Nuclear Information System (INIS)

    This work reports the measurement of the linear attenuation coefficient of ground in order to elaborate a calculus memory for a nuclear medicine installation. The service is placed in the subsoil and the hot room is surrounded by variable, higher than a meter, thicknesses of ground. Owing to the lack of bibliography about the value of the linear attenuation coefficient of ground, we measured it and compared the result with that obtained by the density correction method relative to concrete, using the linear attenuation coefficient value of this material as derived from experimental measures of this material. Measurements were made using a BaF2 scintillation detector and a 137Cs source, which was selected considering the similitude between its energy and the energy of the radiopharmaceutical used in the service for the PET studies, 22Na. Different increasing thicknesses of ground got from areas located near the service were placed as absorbents. The work involves ten experimental points, interposing cumulatively 1.8cm thicknesses of ground each time, between the detector and the source. The results obtained from both methods do not present a significant difference, however, we have concluded that the measured coefficient is more appropriate that the one estimated by the density correction method. Consequently, for calculating the dose rates at different places of the service, the experimentally determined value μ = 0.0884 cm-1 of the linear attenuation coefficient was used. (author)

  13. Identification of a positive-Seebeck-coefficient exohedral fullerene.

    Science.gov (United States)

    Almutlaq, Nasser; Al-Galiby, Qusiy; Bailey, Steven; Lambert, Colin J

    2016-07-14

    If fullerene-based thermoelectricity is to become a viable technology, then fullerenes exhibiting both positive and negative Seebeck coefficients are needed. C60 is known to have a negative Seebeck coefficient and therefore in this paper we address the challenge of identifying a positive-Seebeck-coefficient fullerene. We investigated the thermoelectric properties of single-molecule junctions of the exohedral fullerene C50Cl10 connected to gold electrodes and found that it indeed possesses a positive Seebeck coefficient. Furthermore, in common with C60, the Seebeck coefficient can be increased by placing more than one C50Cl10 in series. For a single C50Cl10, we find S = +8 μV K(-1) and for two C50Cl10's in series we find S = +30 μV K(-1). We also find that the C50Cl10 monomer and dimer have power factors of 0.5 × 10(-5) W m(-1) K(-2) and 6.0 × 10(-5) W m(-1) K(-2) respectively. These results demonstrate that exohedral fullerenes provide a new class of thermoelectric materials with desirable properties, which complement those of all-carbon fullerenes, thereby enabling the boosting of the thermovoltage in all-fullerene tandem structures. PMID:27357101

  14. Rock shape, restitution coefficients and rockfall trajectory modelling

    Science.gov (United States)

    Glover, James; Christen, Marc; Bühler, Yves; Bartelt, Perry

    2014-05-01

    Restitution coefficients are used in rockfall trajectory modelling to describe the ratio between incident and rebound velocities during ground impact. They are central to the problem of rockfall hazard analysis as they link rock mass characteristics to terrain properties. Using laboratory experiments as a guide, we first show that restitution coefficients exhibit a wide range of scatter, although the material properties of the rock and ground are constant. This leads us to the conclusion that restitution coefficients are poor descriptors of rock-ground interaction. The primary problem is that "apparent" restitution coefficients are applied at the rock's centre-of-mass and do not account for rock shape. An accurate description of the rock-ground interaction requires the contact forces to be applied at the rock surface with consideration of the momentary rock position and spin. This leads to a variety of rock motions including bouncing, sliding, skipping and rolling. Depending on the impact configuration a wide range of motions is possible. This explains the large scatter of apparent restitution coefficients. We present a rockfall model based on newly developed hard-contact algorithms which includes the effects of rock shape and therefore is able to reproduce the results of different impact configurations. We simulate the laboratory experiments to show that it is possible to reproduce run-out and dispersion of different rock shapes using parameters obtained from independent tests. Although this is a step forward in rockfall trajectory modelling, the problem of parametersing real terrain remains.

  15. Diffusion coefficient of the decay products of krypton and xenon

    International Nuclear Information System (INIS)

    Measurement of diffusion coefficient of the decay products of krypton and xenon e.g. sup(88,89)Rb and 138Cs is useful for evaluating the inhalation dose and also for the measurement of the concentration of noble gases by double filter method. A diffusion sampler developed by Kotrappa et al., based on Mercer's theory of diffusional deposition between the concentric circular plates was used. The deposition of decay products of krypton and xenon on the circular plates was measured using a multichannel analyser available in this division of BARC (HPGe 4K MCA). Experiments were conducted at 15 and 140 air changes per hour and at different humidities (50-100%). The diffusion coefficient for 88Rb, 89Rb, 138Cs were found to be 0.050±0.008, 0.047±0.008 and 0.047±0.006 respectively at 15 air changes per hour. The diffusion coefficients for these radionuclides were observed to be 0.061±0.005, 0.059±0.006 and 0.058±0.005 at high ventilation rate (140 air changes per hour). This study demonstrates that the diffusion coefficients increase with increasing ventilation rates. The effect of relative humidity on diffusion coefficient is less pronounced at high ventilation rate. (author). 8 refs., 1 fig., 2 tabs

  16. Theoretical approximations and experimental extinction coefficients of biopharmaceuticals.

    Science.gov (United States)

    Miranda-Hernández, Mariana P; Valle-González, Elba R; Ferreira-Gómez, David; Pérez, Néstor O; Flores-Ortiz, Luis F; Medina-Rivero, Emilio

    2016-02-01

    UV spectrophotometric measurement is a widely accepted and standardized routine analysis for quantitation of highly purified proteins; however, the reliability of the results strictly depends on the accuracy of the employed extinction coefficients. In this work, an experimental estimation of the differential refractive index (dn/dc), based on dry weight measurements, was performed in order to determine accurate extinction coefficients for four biotherapeutic proteins and one synthetic copolymer after separation in a size-exclusion ultra-performance liquid chromatograph coupled to an ultraviolet, multiangle light scattering and refractive index (SE-UPLC-UV-MALS-RI) multidetection system. The results showed small deviations with respect to theoretical values, calculated from the specific amino acid sequences, for all the studied immunoglobulins. Nevertheless, for proteins like etanercept and glatiramer acetate, several considerations, such as glycan content, partial specific volume, polarizability, and higher order structure, should be considered to properly calculate theoretical extinction coefficient values. Herein, these values were assessed with simple approximations. The precision of the experimentally obtained extinction coefficients, and its convergence towards the theoretical values, makes them useful for characterization and comparability exercises. Also, these values provide insight into the absorbance and scattering properties of the evaluated proteins. Overall, this methodology is capable of providing accurate extinction coefficients useful for development studies.

  17. Wobble friction coefficient in post-stressed concrete

    Directory of Open Access Journals (Sweden)

    Diego Ernesto Dueñas Puentes

    2010-04-01

    Full Text Available This work was aimed at establishing a wobble friction coefficient (K from records regarding some post-stressed bridges built in Colombia. Such records were arranged and analysed together with stress diagrams resulting from the corres-ponding plans, calculations and reports. Suitable records were produced from this review to make the analysis. Once the records had been selected, the probable wobble friction coefficient (K was then calculated for each case and this coefficient was related to the length of the cable and the total area of the strands composing the cable. These records and their results were subsequently grouped according to the type of bridge to produce a wobble friction coefficient (K for each specific structure. The study indicated that the wobble friction coefficient was lower than that indicated by the Colombian Seismic Bridge Design Code, Instituto Nacional De Vías, 1995]. The influence of tensioning equipment, materials and labour suggested a format for recording tensioning to reduce inaccuracy when readings are being taken. A reduction in the costs of tensioning would arise from taking the forgoing into account.

  18. Order statistics correlation coefficient as a novel association measurement with applications to biosignal analysis

    OpenAIRE

    Xu, W; Chang, C.; Hung, YS; Kwan, SK; Fung, PCW

    2007-01-01

    In this paper, we propose a novel correlation coefficient based on order statistics and rearrangement inequality. The proposed coefficient represents a compromise between the Pearson's linear coefficient and the two rank-based coefficients, namely Spearman's rho and Kendall's tau. Theoretical derivations show that our coefficient possesses the same basic properties as the three classical coefficients. Experimental studies based on four models and six biosignals show that our coefficient perfo...

  19. The relation between salt and ionic transport coefficients.

    Science.gov (United States)

    Kedem, O; Leaf, A

    1966-03-01

    The reflection coefficient was originally introduced by Staverman to describe the movement of nonelectrolytes through membranes. When this coefficient is extended to salts, one has a choice of defining this term for the whole salt moving as a single electrically neutral component or for the individual ions of the salt. The latter definition is meaningful only in the absence of an electric field across the permeability barrier. This condition may be achieved with the voltage clamp or short-circuit technique and is especially useful in dealing with biological systems in which one rarely has only a single salt or even equal concentrations of the major anion and cation. The relations between the transport coefficients for the salt and its individual ions are derived. The special conditions which may result in negative osmosis through a charged membrane in the presence of a salt are discussed. PMID:5943607

  20. Modification of Einstein A Coefficient in Dissipative Gas Medium

    Science.gov (United States)

    Cao, Chang-Qi; Cao, Hui; Qin, Ke-Cheng

    1996-01-01

    Spontaneous radiation in dissipative gas medium such as plasmas is investigated by Langevin equations and the modified Weisskopf-Wigner approximation. Since the refractive index of gas medium is expected to be nearly unity, we shall first neglect the medium polarization effect. We show that absorption in plasmas may in certain case modify the Einstein A coefficient significantly and cause a pit in the A coefficient-density curves for relatively low temperature plasmas and also a pit in the A coefficient-temperature curves. In the next, the effect of medium polarization is taken into account in addition. To our surprise, its effect in certain case is quite significant. The dispersive curves show different behaviors in different region of parameters.

  1. Turbulent MHD transport coefficients - An attempt at self-consistency

    Science.gov (United States)

    Chen, H.; Montgomery, D.

    1987-01-01

    In this paper, some multiple scale perturbation calculations of turbulent MHD transport coefficients begun in earlier papers are first completed. These generalize 'alpha effect' calculations by treating the velocity field and magnetic field on the same footing. Then the problem of rendering such calculations self-consistent is addressed, generalizing an eddy-viscosity hypothesis similar to that of Heisenberg for the Navier-Stokes case. The method also borrows from Kraichnan's direct interaction approximation. The output is a set of integral equations relating the spectra and the turbulent transport coefficients. Previous 'alpha effect' and 'beta effect' coefficients emerge as limiting cases. A treatment of the inertial range can also be given, consistent with a -5/3 energy spectrum power law. In the Navier-Stokes limit, a value of 1.72 is extracted for the Kolmogorov constant. Further applications to MHD are possible.

  2. Multiple element airfoils optimized for maximum lift coefficient.

    Science.gov (United States)

    Ormsbee, A. I.; Chen, A. W.

    1972-01-01

    Optimum airfoils in the sense of maximum lift coefficient are obtained for incompressible fluid flow at large Reynolds number. The maximum lift coefficient is achieved by requiring that the turbulent skin friction be zero in the pressure rise region on the airfoil upper surface. Under this constraint, the pressure distribution is optimized. The optimum pressure distribution is a function of Reynolds number and the trailing edge velocity. Geometries of those airfoils which will generate these optimum pressure distributions are obtained using a direct-iterative method which is developed in this study. This method can be used to design airfoils consisting of any number of elements. Numerical examples of one- and two-element airfoils are given. The maximum lift coefficients obtained range from 2 to 2.5.

  3. Townsend coefficients for electron scattering over dielectric surfaces

    Science.gov (United States)

    Peck, Timothy L.; Kushner, Mark J.

    1988-01-01

    A method for describing the probability of initiating flashover discharges across dielectric surfaces is presented in which a transport coefficient for electron multiplication similar to the Townsend coefficient used for gas discharges is defined. The coefficient is a function of the scaling parameter (charge released from the cathode)/(cathode-anode separation) and is also a measure of the growth of the sheath on the dielectric surface resulting from electron scattering. Results are discussed as to when the source of seed electrons does not necessarily depend upon field emission at the cathode-vacuum-dielectric triple point. For these conditions, there is a different functional dependence of flashover probability on voltage and geometry than when field emission provides the seed electrons. As a result, criteria previously used to predict flashover discharges may not apply.

  4. Quantization Audio Watermarking with Optimal Scaling on Wavelet Coefficients

    CERN Document Server

    Chen, S -T; Tu, S -Y

    2011-01-01

    In recent years, discrete wavelet transform (DWT) provides an useful platform for digital information hiding and copyright protection. Many DWT-based algorithms for this aim are proposed. The performance of these algorithms is in term of signal-to-noise ratio (SNR) and bit-error-rate (BER) which are used to measure the quality and the robustness of an embedded audio. However, there is a tradeoff relationship between the embedded-audio quality and robustness. The tradeoff relationship is a signal processing problem in the wavelet domain. To solve this problem, this study presents an optimization-based scaling scheme using optimal multi-coefficients quantization in the wavelet domain. Firstly, the multi-coefficients quantization technique is rewritten as an equation with arbitrary scaling on DWT coefficients and set SNR to be a performance index. Then, a functional connecting the equation and the performance index is derived. Secondly, Lagrange Principle is used to obtain the optimal solution. Thirdly, the scal...

  5. Optimization of Power Coefficient of Wind Turbine Using Genetic Algorithm

    Science.gov (United States)

    Rajakumar, Sappani; Ravindran, Durairaj; Sivakumar, Mahalingam; Venkatachalam, Gopalan; Muthukumar, Shunmugavelu

    2016-06-01

    In the design of a wind turbine, the goal is to attain the highest possible power output under specified atmospheric conditions. The optimization of power coefficient of horizontal axis wind turbine has been carried out by integration of blade element momentum method and genetic algorithm (GA). The design variables considered are wind velocity, angle of attack and tip speed ratio. The objective function is power coefficient of wind turbine. The different combination of design variables are optimized using GA and then the Power coefficient is optimized. The optimized design variables are validated with the experimental results available in the literature. By this optimization work the optimum design variables of wind turbine can be found economically than experimental work. NACA44XX series airfoils are considered for this optimization work.

  6. Measurement of the ultracold neutron loss coefficient in beryllium powder

    International Nuclear Information System (INIS)

    The ultracold neutron (UCN) reflection from beryllium powder at different slab thicknesses and different packing densities is measured. The reduced UCN loss coefficient η=(1.75±0.35)x10-4 for thermally untreated beryllium is extracted from experimental data. The formerly obtained experimental results on UCN reflection from beryllium after high temperature annealing are reconsidered. The loss coefficient η at room temperature in this case is obtained to be (6.4±2.5)x10-5, which is an order of magnitude higher than the theoretical one. The extraction of the loss coefficient from the experimental data is based on the modified diffusion theory where albedo reflection depends on packing density

  7. Transport coefficients for dense hard-disk systems.

    Science.gov (United States)

    García-Rojo, Ramón; Luding, Stefan; Brey, J Javier

    2006-12-01

    A study of the transport coefficients of a system of elastic hard disks based on the use of Helfand-Einstein expressions is reported. The self-diffusion, the viscosity, and the heat conductivity are examined with averaging techniques especially appropriate for event-driven molecular dynamics algorithms with periodic boundary conditions. The density and size dependence of the results are analyzed, and comparison with the predictions from Enskog's theory is carried out. In particular, the behavior of the transport coefficients in the vicinity of the fluid-solid transition is investigated and a striking power law divergence of the viscosity with density is obtained in this region, while all other examined transport coefficients show a drop in that density range in relation to the Enskog's prediction. Finally, the deviations are related to shear band instabilities and the concept of dilatancy. PMID:17280060

  8. Estimating transport coefficients in hot and dense quark matter

    CERN Document Server

    Deb, Paramita; Mishra, Hiranmaya

    2016-01-01

    We compute the transport coefficients-- namely, coefficients of shear and bulk viscosity as well as thermal conductivity for hot and dense quark matter. The calculations are performed within the Nambu Jona Lasinio (NJL) model. The estimation of the transport coefficients is made using a quasi particle approach of solving Boltzmann kinetic equation within the relaxation time approximation. The transition rates are calculated in a manifestly covariant manner to estimate the thermal averaged cross sections for quark quark as well as quark anti-quark scattering. The calculations are performed for finite chemical potential also. Within the parameters of the model, the ratio of shear viscosity to entropy density has a minimum at the Mott transition temperature. At vanishing chemical potential, the ratio of bulk viscosity to entropy density, on the other hand, decrease with temperature with a sharp decrease near the critical temperature and vanishes beyond it. At finite chemical potential, however, it increases slow...

  9. The Study on Pipe Sudden Enlargement Local Resistant Coefficient

    Institute of Scientific and Technical Information of China (English)

    ZhaoBao-feng; JinYing-zi; 等

    1999-01-01

    During the design of pipeline,the determination of local resistent coefficient is often come arcoss.The sudden enlargement local resistant coefficient ξ1=[1-A1/A2]2 is determined through theory.In the paper,the sudden enlargement local resistant coefficient under the conditions of three kinds of A1/A2 was studied in experiment.In the end,the result shows that ξ1 is related not only to two flow cross sections,but also to the velocity.Thyough experimental research,the relationship between ξ1,A1/A2 and V1 was determined.In a word,the hydraulic calculation of pipeline can be done by taking correspondent ξ1,according to the design velocity V1 and A1/A2.

  10. Innovative Fast Reactors: Impact of Fuel Composition on Reactivity Coefficients

    International Nuclear Information System (INIS)

    A major challenge for future Fast Reactors could be the recycling of minor actinides (MA) in the core fuel, in order to minimize wastes and contribute to meet both the sustainability objective and the reduction of the burden on a geological disposal. Although the most outstanding issues will be found in the development and validation of the appropriate fuels, the presence of MA in the core can potentially deteriorate the core reactivity coefficients. In the present paper we will show however that there is no physical limit to the amount of MA in the core fuel, but that a careful physics analysis can indicate the most appropriate measures to reduce the MA impact on the reactivity coefficients, and in particular, for Na cooled reactors, on the Na void reactivity coefficient.

  11. The effect of nuclear rotation on the collective transport coefficients

    International Nuclear Information System (INIS)

    We have examined the influence of rotation on the potential energy and the transport coefficients of the collective motion (friction and mass coefficients). For axially symmetric deformation of nucleus 224Th we found that at excitations corresponding to temperatures T≥1 MeV the shell correction to the liquid-drop energy practically does not depend on the angular rotation. The friction and mass coefficients obtained within the linear response theory for the same nucleus at temperatures larger than 2 MeV are rather stable with respect to rotation provided that the contributions from spurious states arising due to the violation of rotation symmetry are removed. At smaller excitations both friction and mass parameters corresponding to the elongation mode are growing functions of rotational frequency ωrot

  12. Dose coefficients from incorporated 129 Iodine. Influence of dietary intake

    International Nuclear Information System (INIS)

    Dose coefficients from incorporated 129 Iodine. Influence of Dietary intake. Internal dose coefficients recently published by the International Commission on Radiological Protection, and adopted in the new European Directive, allow direct calculation of the committed effective dose by multiplying the intake of radionuclide, expressed as becquerels, Bq, by those dose coeffIcients. For iodine, however, this methodology needs adaptation as iodine uptake by thyroid from blood is ruled by an adjustment process to the daily iodine intake: The greater that intake, the smaller the iodine fraction of thyroid uptake. Dealing with the 129 iodine radioactive isotope, for a same ingested Bq, the uptake factor can vary, from 0.3, for a daily dietary intake of 165 μg, to 0.03 for a daily dietary intake of 2.2 mg. Illustrations of this variability are simulated in several situations that could involve contaminated water consumption. (authors)

  13. Interpolation and Convergence of Bernstein-Bézier Coefficients

    Institute of Scientific and Technical Information of China (English)

    Feng Jun LI

    2011-01-01

    In this paper,two ways of the proof are given for the fact that the Berustein-Bézier coefficients (BB-coefficients) of a multivariate polynomial converge uniformly to the polynomial under repeated degree elevation over the simplex.We show that the partial derivatives of the inverse Bernstein polynomial An(g) converge uniformly to the corresponding partial derivatives of g at the rate 1/n.We also consider multivariate interpolation for the BB-coefficients,and provide effective interpolation formulas by using Bernstein polynomials with ridge form which essentially possess the nature of univariate polynomials in computation,and show that Bernstein polynomials with ridge form with least degree can be constructed for interpolation purpose,and thus a computational algorithm is provided correspondingly.

  14. Microchip for the Measurement of Seebeck Coefficients of Single Nanowires

    Science.gov (United States)

    Völklein, F.; Schmitt, M.; Cornelius, T. W.; Picht, O.; Müller, S.; Neumann, R.

    2009-07-01

    Bismuth nanowires were electrochemically grown in ion track-etched polycarbonate membranes. Micromachining and microlithography were employed to realize a newly developed microchip for Seebeck coefficient measurements on individual nanowires. By anisotropic etching of a (100) Si wafer, an 800-nm-thick SiO2/Si3N4 membrane was prepared in the chip center. The low thermal conductivity of the membrane is crucial to obtain the required temperature difference Δ T along the nanowire. The wire is electrically contacted to thin metal pads which are patterned by a new method of microscopic exposure of photoresist and a lift-off process. A Δ T between the two pairs of contact pads, located on the membrane, is established by a thin-film heater. Applying the known Seebeck coefficient of a reference film, the temperature difference at this gap is determined. Using Δ T and the measured Seebeck voltage U of the nanowire, its Seebeck coefficient can be calculated.

  15. Distributing Correlation Coefficients of Linear Structure-Activity/Property Models

    Directory of Open Access Journals (Sweden)

    Sorana D. BOLBOACA

    2011-12-01

    Full Text Available Quantitative structure-activity/property relationships are mathematical relationships linking chemical structure and activity/property in a quantitative manner. These in silico approaches are frequently used to reduce animal testing and risk-assessment, as well as to increase time- and cost-effectiveness in characterization and identification of active compounds. The aim of our study was to investigate the pattern of correlation coefficients distribution associated to simple linear relationships linking the compounds structure with their activities. A set of the most common ordnance compounds found at naval facilities with a limited data set with a range of toxicities on aquatic ecosystem and a set of seven properties was studied. Statistically significant models were selected and investigated. The probability density function of the correlation coefficients was investigated using a series of possible continuous distribution laws. Almost 48% of the correlation coefficients proved fit Beta distribution, 40% fit Generalized Pareto distribution, and 12% fit Pert distribution.

  16. Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients

    CERN Document Server

    Kheder, G; Massoued, M Ben; Samet, M

    2009-01-01

    In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

  17. Anomaly induced transport coefficients, from weak to strong coupling

    CERN Document Server

    Pena-Benitez, Francisco

    2013-01-01

    The existence of new transport phenomena associated to the presence of quantum anomalies has atracted very recently the attention of theorist. These transport coefficient have very interesting properties, for example, they do not renormalize. The most famous case of anomaly induced transport phenomena is the Chiral Magnetic Effect, in which an electric current is produced by a magnetic field if the system has a different number of right handed fermions respect the left handed one. In this thesis we have studied those transport coefficients from Kubo formulas at weak and strong coupling. To finish a fluid/gravity approach is used to compute all the second order anomalous coefficients in an anomalous conformal fluid.

  18. 3D contaminant migration model with consolidation dependent transport coefficients

    Institute of Scientific and Technical Information of China (English)

    Lu Huang; Cheng-Gang Zhao; Yan Liu; Guo-Qing Cai

    2012-01-01

    Soil consolidation would induce variations of its transport coefficients such as hydraulic conductivity and diffusion coefficient. This paper presents a study of the influence of barrier consolidation on transport coefficients,and a 3D transport model based on mixture theory is proposed for describing the liners that involve circular defects in the geomembrane.The elastoplastic ALPHA model is revised by using the spatially mobilized plane (SMP) criterion for simulating the deformation of the soils.Then,the 3D model coupling the nonlinear consolidation and contaminant advection-diffusion is solved using the finite element software ABAQUS.The results show that the importance of reducing the defect size in the geomembrane and the liner porosity to control the contaminant concentration increase.

  19. Reducing component estimation for varying coefficient models with longitudinal data

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Varying-coefficient models with longitudinal observations are very useful in epidemiology and some other practical fields.In this paper,a reducing component procedure is proposed for es- timating the unknown functions and their derivatives in very general models,in which the unknown coefficient functions admit different or the same degrees of smoothness and the covariates can be time- dependent.The asymptotic properties of the estimators,such as consistency,rate of convergence and asymptotic distribution,are derived.The asymptotic results show that the asymptotic variance of the reducing component estimators is smaller than that of the existing estimators when the coefficient functions admit different degrees of smoothness.Finite sample properties of our procedures are studied through Monte Carlo simulations.

  20. SKEWNESS OF RETURN DISTRIBUTION AND COEFFICIENT OF RISK PREMIUM

    Institute of Scientific and Technical Information of China (English)

    Fenghua WEN; Xiaoguang YANG

    2009-01-01

    The skewness of the return distribution is one of the important features of the security price. In this paper, the authors try to explore the relationship between the skewness and the coefficient of risk premium. The coefficient of the risk premium is estimated by a GARCH-M model, and the robust measurement of skewness is calculated by Groeneveld-Meeden method. The empirical evidences for the composite indexes from 33 securities markets in the world indicate that the risk compensation requirement in the market where the return distribution is positively skewed is virtually zero, and the risk compensation requirement is positive in a significant level in the market where the return distribution is negative skewed. Moreover, the skewness is negatively correlated with the coefficient of the risk premium.

  1. On the conversion coefficients for cosmic ray dosimetry

    CERN Document Server

    Ferrari, Alfredo

    2003-01-01

    Calculations of fluence-to-effective dose conversion coefficients have typically been limited to the standard irradiation geometries of the human body: anterior-to-posterior (AP), posterior-to-anterior (PA), lateral from the right side to the left side (RLAT), lateral from the left side to the right side (LLAT), rotational around the vertical axis (ROT), and isotropic incidence from all directions (ISO). In order to estimate the doses to air crew members exposed to cosmic radiation, the geometrical conditions of irradiation are usually assumed to be isotropic. However, the assumption of isotropic irradiation is in many cases invalid for the high energy component of the radiation field, which is often peaked in the forward direction. Therefore, it was considered useful to extend the calculations of conversion coefficients to other geometries. New sets of conversion coefficients fluence-to-effective dose are presented for the semiisotropic irradiation of the human body and for the irradiation from the top. Thei...

  2. Scattering and absorption coefficients of silica-doped alumina aerogels.

    Science.gov (United States)

    Fu, Tairan; Tang, Jiaqi; Chen, Kai; Zhang, Fan

    2016-02-01

    Alumina-based aerogels are especially useful in many applications due to their excellent stability at high temperatures. This study experimentally analyzed the radiative properties of silica-doped alumina aerogels through spectral directional-hemispherical measurements for wavelengths of 0.38-25 μm. The silica-doped alumina aerogel samples were prepared with a 1.4∶1 molar ratio of silica to alumina. A two-flux model was used to describe the radiation propagation in a 1D scattering absorbing sample to derive expressions for the normal-hemispherical transmittances and reflectances based on the transport approximation. The normal-hemispherical transmittances and reflectances were measured at various spectral wavelengths and sample thicknesses using the integrating sphere method. The spectral absorption and transport scattering coefficients of silica-doped alumina aerogels were then determined from the measured normal-hemispherical data. The absorption and transport scattering coefficients of silica-doped alumina aerogels are (0.1  cm-1, 36  cm-1) and (0.1  cm-1, 112  cm-1) for wavelengths of 0.38-8.0 μm. The spectral transport scattering coefficient varies in the opposite direction from the spectral absorption coefficient for various wavelengths. The radiative properties for silica and alumina aerogels were quite different for the absorption coefficient for wavelengths of 2.5-8.0 μm and for the transport scattering coefficient for wavelengths of 0.38-2.5 and 3.5-6.0 μm. The measured radiative properties were used to predict the spectral normal-hemispherical reflectance and transmittance of the silica-doped alumina aerogels for various sample thicknesses and wavelengths. The predicted values do not change for the sample thicknesses greater than a critical value. The analysis provides valuable reference data for alumina aerogels for high-temperature applications. PMID:26836071

  3. Nonlinear piezoelectric coefficients of ferroelectrics in the phase transition region

    Energy Technology Data Exchange (ETDEWEB)

    Iushin, N.K.; Smirnov, S.I.; Turovets, A.G.; Linnik, V.G.; Agishev, B.A.

    1987-03-01

    Changes in the nonlinear piezoelectric coefficients in ferroelectrics in the phase transition region are investigated experimentally using triglycine sulfate, lead germanate, potassium-lithium tantalate, and cadmium pyroniobate crystals, characterized by phase transitions of the second kind, and also gadolinium and terbium molybdate crystals, characterized by a ferroelectric phase transition of the first kind. In the crystals studied, a significant increase in nonlinear piezoelectric coefficients is observed near the phase transition temperature, which makes these crystals attractive materials for use as the elements of nonlinear acoustoelectronic instruments. 9 references.

  4. Trends in the isobaric multiplet mass equation coefficients

    International Nuclear Information System (INIS)

    Isobaric analogue states (IAS) can be used to study the charge independence of the nuclear force via first order perturbation theory. In this case the IAS multiplet masses are expected to follow a quadratic form as described by the Isobaric Multiplet Mass Equation (IMME) with coefficients accessible through experimental measurements. Higher order effects are expected to appear through cubic, or higher, polynomial terms. The current IMME coefficient trends, as based on the IAS states included in the 2012 Atomic Mass Evaluation and NUBASE2012 are shown. (authors)

  5. Acoustic Emotion Recognition Using Linear and Nonlinear Cepstral Coefficients

    Directory of Open Access Journals (Sweden)

    Farah Chenchah

    2015-11-01

    Full Text Available Recognizing human emotions through vocal channel has gained increased attention recently. In this paper, we study how used features, and classifiers impact recognition accuracy of emotions present in speech. Four emotional states are considered for classification of emotions from speech in this work. For this aim, features are extracted from audio characteristics of emotional speech using Linear Frequency Cepstral Coefficients (LFCC and Mel-Frequency Cepstral Coefficients (MFCC. Further, these features are classified using Hidden Markov Model (HMM and Support Vector Machine (SVM.

  6. NICIL: Non-Ideal magnetohydrodynamics Coefficients and Ionisation Library

    Science.gov (United States)

    Wurster, James

    2016-08-01

    NICIL (Non-Ideal magnetohydrodynamics Coefficients and Ionisation Library) calculates the ionization values and the coefficients of the non-ideal magnetohydrodynamics terms of Ohmic resistivity, the Hall effect, and ambipolar diffusion. Written as a standalone Fortran90 module that can be implemented in existing codes, NICIL is fully parameterizable, allowing the user to choose which processes to include and decide the values of the free parameters. The module includes both cosmic ray and thermal ionization; the former includes two ion species and three species of dust grains (positively charged, negatively charged and neutral), and the latter includes five elements which can be doubly ionized.

  7. Determination of the First Townsend Coefficient in Pure Isobutane

    Science.gov (United States)

    Lima, Iara B.; Vivaldini, Túlio C.; Gonçalves, Josemary A. C.; Botelho, Suzana; Ridenti, Marco A.; Fonte, Paulo; Mangiarotti, Alessio; Pascholati, Paulo R.; Tobias, Carmen C. Bueno

    2011-08-01

    In this work studies of the first Townsend coefficient (α) behavior in isobutane for reduced electric fields ranging from l39Td up to 2O8Td are presented. Pure isobutane has been widely used in Resistive Plate Chambers (RPCs) and other gaseous detectors because of its excellent timing properties. Regardless of these characteristics, there is a lack of swarm parameters data in the literature for this gas. The measurements were based on the Pulsed Townsend technique. Considering the ratio between the current, measured in avalanche mode, and the primary ionization current, the first Townsend coefficient can be determined. In order to validate the technique, results for nitrogen are also presented.

  8. On the Fourier coefficients of negative index meromorphic Jacobi forms

    CERN Document Server

    Bringmann, Kathrin; Zwegers, Sander

    2015-01-01

    In this paper, we consider the Fourier coefficients of meromorphic Jacobi forms of negative index. This extends recent work of Creutzig and the first two authors for the special case of Kac-Wakimoto characters which occur naturally in Lie theory, and yields, as easy corollaries, many important PDEs arising in combinatorics such as the famous rank-crank PDE of Atkin and Garvan. Moreover, we discuss the relation of our results to partial theta functions and quantum modular forms as introducted by Zagier, which together with previous work on positive index meromorphic Jacobi forms illuminates the general structure of the Fourier coefficients of meromorphic Jacobi forms.

  9. Effect of coking conditions on Rankin coefficient of coke cake

    Energy Technology Data Exchange (ETDEWEB)

    Arima, T.; Fukuda, K.; Kato, K. [Nippon Steel Corp. Ltd., Futtsu (Japan). Environmental & Process Technology Center

    2004-09-01

    An innovative cokemaking process, SCOPE21 (Super Coke Oven for Productivity and Environmental enhancement toward the 21st century), has been developed by JISF (The Japan Iron and Steel Federation) and CCUJ (Center for Coal Utilization, Japan). As a cokemaking process, it is important to guarantee safe and stable pushing. Coke pushing behavior was studied by using a pilot-scale coke oven and influence of coking conditions on the Rankin coefficient was investigated. It was found that Rankin coefficient was dependent on lateral shrinkage and fissure density in coke cake and that it can be controlled by controlling the fissure density in SCOPE21 process.

  10. H-Optimal Control in Coefficients for Dirichlet Parabolic Problems

    Directory of Open Access Journals (Sweden)

    I. G. Balanenko

    2010-01-01

    Full Text Available In the paper the Dirichlet optimal control problem associated with a linear parabolic equation the coefficients of which we take as controls in L1(Ω has been studied. Since equations of this type can exhibit the Lavrentieff phenomenon and non-uniqueness of weak solutions, it is shown that the optimal control problem in the coefficients can be stated in different settings depending on the choice of the class of admissible solutions. Using the direct method in the Calculus of Variations, the solvability of the above optimal control problems in the so-called class of inadmissible solutions has been discussed.

  11. Design of wind turbine airfoils based on maximum power coefficient

    DEFF Research Database (Denmark)

    Chen, Jin; Cheng, Jiangtao; Shen, Wenzhong;

    2010-01-01

    noise prediction model, the previously developed integrated design technique is further developed. The new code takes into account different airfoil requirements according to their local positions on a blade, such as sensitivity to leading edge roughness, design lift at off-design condition, stall......Based on the blade element momentum (BEM) theory, the power coefficient of a wind turbine can be expressed in function of local tip speed ratio and lift-drag ratio. By taking the power coefficient in a predefined range of angle of attack as the final design objective and combining with an airfoil...

  12. Partially linear varying coefficient models stratified by a functional covariate

    KAUST Repository

    Maity, Arnab

    2012-10-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric component and a profiling estimator of the parametric component of the model and derive their asymptotic properties. Specifically, we show the consistency of the nonparametric functional estimates and derive the asymptotic expansion of the estimates of the parametric component. We illustrate the performance of our methodology using a simulation study and a real data application.

  13. Riesz frames and approximation of the frame coefficients

    DEFF Research Database (Denmark)

    Casazza, P.; Christensen, Ole

    1998-01-01

    A frame is a fmaily {f i } i=1 ∞ of elements in a Hilbert space with the property that every element in can be written as a (infinite) linear combination of the frame elements. Frame theory describes how one can choose the corresponding coefficients, which are called frame coefficients. From...... avoided the inversion problem. In the same spirit we approximate the solution to a moment problem. It turns out, that the class of “well-behaving frames” are identical for the two problems we consider....

  14. Riesz Frames and Approximation of the Frame Coefficients

    DEFF Research Database (Denmark)

    Christensen, Ole

    1996-01-01

    A frame is a familyof elements in a Hilbert space with the propertythat every element in the Hilbert space can be written as a (infinite)linear combination of the frame elements. Frame theory describes howone can choose the corresponding coefficients, which are calledframe coefficients. From...... the mathematical point of view this isgratifying, but for applications it is a problem that the calculationrequires inversion of an operator on the Hilbert space.The projection method is introduced in order to avoid this problem.The basic idea is to consider finite subfamiliesof the frame and the orthogonal...

  15. Heavy mesons in a hadronic medium: interaction and transport coefficients

    CERN Document Server

    Torres-Rincon, Juan M; Cabrera, Daniel; Romanets, Olena; Tolos, Laura

    2015-01-01

    We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B-bar mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker-Planck reduction of the Boltzmann equation.

  16. BIT LENGTH REPLACEMENT STEGANOGRAPHY BASED ON DCT COEFFICIENTS

    Directory of Open Access Journals (Sweden)

    K B Shiva Kumar

    2010-08-01

    Full Text Available Steganography is a means of establishing secret communication through public channel in an artistic manner. In this paper, we propose Bit Length Replacement Steganography Based on DCT Coefficients (BLSDCT . The cover image is segmented into 8*8 blocks and DCT is applied on each block. The numbers of payload MSB bits are embedded into DCT coefficients of the cover image based on the values of DCT oefficients. It is observed that the proposed algorithm has better PSNR, Security and capacity compared to the existing algorithm.

  17. Correlation coefficients and the Robertson-Schroedinger uncertainty relations

    OpenAIRE

    Fleming, Gordon N.

    2007-01-01

    Calling the quantity; 2delta(A)delta(B)/||, with non-zero denominator, the uncertainty product ratio or UPR for the pair of observables, (A, B), it is shown that any non-zero correlation coefficient between two observables raises, above unity, the lower bound of the UPR for each member of an infinite collection of pairs of incompatible observables. Conversely, any UPR is subject to lower bounds above unity determined by each of an infinite collection of correlation coefficients. This result g...

  18. Adhesion coefficient of automobile tire and road surface

    Institute of Scientific and Technical Information of China (English)

    刘长生

    2008-01-01

    The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.

  19. Tilting pad journal bearings - Measured and predicted stiffness coefficients

    Science.gov (United States)

    Parkins, D. W.; Horner, D.

    1993-07-01

    This paper presents measured and calculated characteristics of a tilting pad journal bearing suitable for high speed machinery. Descriptions are given of the experimental techniques used with this variety of bearing and the theoretical model for predicting performance. Measured values of pad temperature, eccentricity, attitude angle, and the four stiffness coefficients are given for a range of loads and rotational speeds. Data are given for both load on pad and between pad configurations, the two principal loading arrangements. Comparisons are made between the measured and predicted bearing temperatures and stiffness coefficients over a wide range of values.

  20. Trends in the Isobaric Multiplet Mass Equation Coefficients

    Directory of Open Access Journals (Sweden)

    MacCormick Marion

    2014-03-01

    Full Text Available Isobaric analogue states (IAS can be used to study the charge independence of the nuclear force via first order perturbation theory. In this case the IAS multiplet masses are expected to follow a quadratic form as described by the Isobaric Multiplet Mass Equation (IMME with coefficients accessible through experimental measurements. Higher order effects are expected to appear through cubic, or higher, polynomial terms. The current IMME coefficient trends, as based on the IAS states included in the 2012 Atomic Mass Evaluation and NUBASE2012 are shown.

  1. Calculation of self-diffusion coefficients in iron

    Directory of Open Access Journals (Sweden)

    Baohua Zhang

    2014-01-01

    Full Text Available On the basis of available P-V-T equation of state of iron, the temperature and pressure dependence of self-diffusion coefficients in iron polymorphs (α, δ, γ and ɛ phases have been successfully reproduced in terms of the bulk elastic and expansivity data by means of a thermodynamical model that interconnects point defects parameters with bulk properties. The calculated diffusion parameters, such as self-diffusion coefficient, activation energy and activation volume over a broad temperature range (500-2500 K and pressure range (0-100 GPa, compare favorably well with experimental or theoretical ones when the uncertainties are considered.

  2. A neural network method to evaluate consolidation coefficient

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Many methods to calculate the consolidation coefficient of soil depend on judgment of testing curves of consolidation,and the calculation result is influenced by artificial factors. In this work, based on the main principle of back propagation neural network, a neural network model to determine the consolidation coefficient is established. The essence of the method is to simulate a serial of compression ratio and time factor curves because the neural network is able to process the nonlinear problems. It is demonstrated that this BP model has high precision and fast convergence. Such method avoids artificial influence factor successfully and is adapted to computer processing.

  3. Estimation of octanol/water partition coefficients using LSER parameters

    Science.gov (United States)

    Luehrs, Dean C.; Hickey, James P.; Godbole, Kalpana A.; Rogers, Tony N.

    1998-01-01

    The logarithms of octanol/water partition coefficients, logKow, were regressed against the linear solvation energy relationship (LSER) parameters for a training set of 981 diverse organic chemicals. The standard deviation for logKow was 0.49. The regression equation was then used to estimate logKow for a test of 146 chemicals which included pesticides and other diverse polyfunctional compounds. Thus the octanol/water partition coefficient may be estimated by LSER parameters without elaborate software but only moderate accuracy should be expected.

  4. Interfacial tension and spreading coefficient for thin films.

    Science.gov (United States)

    Tadmor, Rafael; Pepper, Ken G

    2008-04-01

    We present a modified mathematical expression for the interfacial tension of very thin films. At large thicknesses the modified expression converges to the classic mathematical expression. We use this modified expression to derive an equation for the spreading coefficient as a function of film thickness. The spreading coefficient equation is then used to calculate the equilibrium thickness of a wetting liquid film for a "pancake drop". Our predictions agree with experimental data. The study is subjected to systems with van der Waals interactions only. PMID:18318550

  5. Partially Linear Varying Coefficient Models Stratified by a Functional Covariate.

    Science.gov (United States)

    Maity, Arnab; Huang, Jianhua Z

    2012-10-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric component and a profiling estimator of the parametric component of the model and derive their asymptotic properties. Specifically, we show the consistency of the nonparametric functional estimates and derive the asymptotic expansion of the estimates of the parametric component. We illustrate the performance of our methodology using a simulation study and a real data application.

  6. Dose coefficients for intakes of radionuclides by workers: Coefficients for radionuclides not listed in ICRP Publication 68

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Akira; Yamaguchi, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-12-01

    Dose coefficients, the committed effective dose per unit intake, have been calculated for 149 radionuclides with half-lives {>=} 10 min that are not listed in ICRP Publication 68 (Publ. 68). Effective dose rates for inert gas have been calculated for 2 radionuclides. The dose coefficients were calculated with the computer program LUDEP that calculates internal doses using the respiratory tract model of ICRP Publ. 66 and the biokinetic models of Publ. 30. Nuclear decay data used for the calculation were newly compiled from decay data sets of the Evaluated Nuclear Structure Data File (ENSDF). In the calculation of the effective dose rates, external irradiation from the surrounding cloud and irradiation of the lung from the gas within it were considered. The calculated results are presented in tables, which are the same forms as those in Publ. 68. The range of the differences in the dose coefficients due to the biokinetic models and nuclear decay data employed was also discussed by comparing the dose coefficients between LUDEP and Publ. 68. The dose coefficients and the effective dose rates will be used for dose calculation for radionuclides produced in high-energy proton accelerator and fusion reactor facilities. (author)

  7. Dose coefficients for radionuclides produced in high energy proton accelerator facilities. Coefficients for radionuclides not listed in ICRP publications

    CERN Document Server

    Kawai, K; Noguchi, H

    2002-01-01

    Effective dose coefficients, the committed effective dose per unit intake, by inhalation and ingestion have been calculated for 304 nuclides, including (1) 230 nuclides with half-lives >= 10 min and their daughters that are not listed in ICRP Publications and (2) 74 nuclides with half-lives < 10 min that are produced in a spallation target. Effective dose coefficients for inhalation of soluble or reactive gases have been calculated for 21 nuclides, and effective dose rates for inert gases have been calculated for 9 nuclides. Dose calculation was carried out using a general-purpose nuclear decay database DECDC developed at JAERI and a decay data library newly compiled from the ENSDF for the nuclides abundantly produced in a spallation target. The dose coefficients were calculated with the computer code DOCAP based on the respiratory tract model and biokinetic model of ICRP. The effective dose rates were calculated by considering both external irradiation from the surrounding cloud and irradiation of the lun...

  8. Noninvasive determination of absorption coefficient and reduced scattering coefficient of human skin tissues in vivo with oblique-incidence reflectometry

    Institute of Scientific and Technical Information of China (English)

    Ping Sun; Yu Wang; Xiaoli Mo; Jinghui Xie

    2008-01-01

    A spatial distribution of diffuse reflectance produced by obliquely incident light is not centered about the point of light entry. The value of shift in the center of diffuse reflectance is directly related to the absorption coefficient μa and the effective attenuation coefficient μeff. μa and the reduced scattering coefficient μ's of human skin tissues in vivo are measured by oblique-incidence reflectometry based on the two-source diffuse theory model. For ten Chinese volunteers aged 15-63 years, μa and μ's are noninvasively determined to be 0.029 - 0.075 and 0.52 - 0.97 mm-1, respectively.

  9. Similarity analysis between chromosomes of Homo sapiens and monkeys with correlation coefficient, rank correlation coefficient and cosine similarity measures.

    Science.gov (United States)

    Someswara Rao, Chinta; Viswanadha Raju, S

    2016-03-01

    In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship between the H. sapiens and monkey. This similarity will be helpful at theft identification, maternity identification, disease identification, etc. PMID:26981409

  10. A new method of solving the coefficient inverse problem

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper is concerned with the new method for solving the coefficient inverse problem in the reproducing kernel space. It is different from the previous studies. This method gives accurate results and shows that it is valid by the numerical example.

  11. Conversion coefficients for determining organ doses in paediatric spine radiography

    Energy Technology Data Exchange (ETDEWEB)

    Seidenbusch, Michael; Schneider, Karl [Ludwig-Maximilians-University of Munich, Institute of Clinical Radiology - Paediatric Radiology, Muenchen (Germany)

    2014-04-15

    Knowledge of organ and effective doses achieved during paediatric x-ray examinations is an important prerequisite for assessment of radiation burden to the patient. Conversion coefficients for reconstruction of organ and effective doses from entrance doses for segmental spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients are provided regarding the Guidelines of Good Radiographic Technique of the European Commission. Using the personal computer program PCXMC developed by the Finnish Centre for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional segmental spine radiographs were calculated performing Monte Carlo simulations in mathematical hermaphrodite phantom models describing patients of different ages. The clinical variation of beam collimation was taken into consideration by defining optimal and suboptimal radiation field settings. Conversion coefficients for the reconstruction of organ doses in about 40 organs and tissues from measured entrance doses during cervical, thoracic and lumbar spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients were calculated for the standard sagittal and lateral beam projections and the standard focus detector distance of 115 cm. The conversion coefficients presented may be used for organ dose assessments from entrance doses measured during spine radiographs of patients of all age groups and all field settings within the optimal and suboptimal standard field settings. (orig.)

  12. Hydrophobicity and Retention Coefficient of Selected Bile Acid Oxo Derivatives

    NARCIS (Netherlands)

    Posa, Mihalj; Pilipovic, Ana; Lalic, Mladena; Popovic, Jovan

    2010-01-01

    Retention coefficients (k) of cholic acid and its keto derivatives are determined by means of Reversed Phase High Pressure Liquid Chromatography at different temperatures (303K, 309K, and 313K). At each studied temperature, retention factor decreases if the hydroxyl group in the cholic acid molecule

  13. The Importance of Structure Coefficients in Interpreting Regression Research.

    Science.gov (United States)

    Heidgerken, Amanda D.

    The paper stresses the importance of consulting beta weights and structure coefficients in the interpretation of regression results. The effects of multilinearity and suppressors and their effects on interpretation of beta weights are discussed. It is concluded that interpretations based on beta weights only can lead the unwary researcher to…

  14. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  15. Friction analysis of kinetic schemes : the friction coefficient

    NARCIS (Netherlands)

    Lolkema, Juke S.

    1995-01-01

    Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free ener

  16. FRICTION ANALYSIS OF KINETIC SCHEMES - THE FRICTION COEFFICIENT

    NARCIS (Netherlands)

    LOLKEMA, JS

    1995-01-01

    Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free ener

  17. Regression Models for Predicting Force Coefficients of Aerofoils

    Directory of Open Access Journals (Sweden)

    Mohammed ABDUL AKBAR

    2015-09-01

    Full Text Available Renewable sources of energy are attractive and advantageous in a lot of different ways. Among the renewable energy sources, wind energy is the fastest growing type. Among wind energy converters, Vertical axis wind turbines (VAWTs have received renewed interest in the past decade due to some of the advantages they possess over their horizontal axis counterparts. VAWTs have evolved into complex 3-D shapes. A key component in predicting the output of VAWTs through analytical studies is obtaining the values of lift and drag coefficients which is a function of shape of the aerofoil, ‘angle of attack’ of wind and Reynolds’s number of flow. Sandia National Laboratories have carried out extensive experiments on aerofoils for the Reynolds number in the range of those experienced by VAWTs. The volume of experimental data thus obtained is huge. The current paper discusses three Regression analysis models developed wherein lift and drag coefficients can be found out using simple formula without having to deal with the bulk of the data. Drag coefficients and Lift coefficients were being successfully estimated by regression models with R2 values as high as 0.98.

  18. Extracting OPE coefficient of Konishi at four loops

    CERN Document Server

    Gonçalves, Vasco

    2016-01-01

    We compute in this short note the OPE coefficient of two 20' operators and the Konishi. We use the OPE decomposition of a four point function of four 20' operators and the method of asymptotic expansions to compute the integrals at the order that it is needed.

  19. An experimental assembly for precise measurement of thermal accommodation coefficients.

    Science.gov (United States)

    Trott, Wayne M; Castañeda, Jaime N; Torczynski, John R; Gallis, Michael A; Rader, Daniel J

    2011-03-01

    An experimental apparatus has been developed to determine thermal accommodation coefficients for a variety of gas-surface combinations. Results are obtained primarily through measurement of the pressure dependence of the conductive heat flux between parallel plates separated by a gas-filled gap. Measured heat-flux data are used in a formula based on Direct Simulation Monte Carlo (DSMC) simulations to determine the coefficients. The assembly also features a complementary capability for measuring the variation in gas density between the plates using electron-beam fluorescence. Surface materials examined include 304 stainless steel, gold, aluminum, platinum, silicon, silicon nitride, and polysilicon. Effects of gas composition, surface roughness, and surface contamination have been investigated with this system; the behavior of gas mixtures has also been explored. Without special cleaning procedures, thermal accommodation coefficients for most materials and surface finishes were determined to be near 0.95, 0.85, and 0.45 for argon, nitrogen, and helium, respectively. Surface cleaning by in situ argon-plasma treatment reduced coefficient values by up to 0.10 for helium and by ∼0.05 for nitrogen and argon. Results for both single-species and gas-mixture experiments compare favorably to DSMC simulations. PMID:21456801

  20. Evaluating transport coefficients in real time thermal field theory

    CERN Document Server

    Mallik, S

    2012-01-01

    Transport coefficients in a hadronic gas have been calculated earlier in the imaginary time formulation of thermal field theory. The steps involved are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we carry out both the steps in the real time formulation.

  1. Overall Heat and Mass Transfer Coefficient of Water Vapor Adsorption

    Science.gov (United States)

    Hamamoto, Yoshinori; Mori, Hideo; Godo, Masazumi; Miura, Kunio; Watanabe, Yutaka; Ishizawa, Toshihiko; Takatsuka, Takeshi

    A fundamental investigation was performed to develop a compact and simple desiccant ventilation unit which is one of the main components of a novel energy saving air-conditioning system. Water vapor in the air is adsorbed and/or desorbed to be controlled the humidity of supply air through a unit of an adsorbent packed bed. A numerical simulation helps to understand the phenomena of heat and mass transfer in the bed. Overall transfer coefficients of them as properties for the simulation were estimated by performing both experiment and calculation. It was clarified that the transient overall equivalent heat and mass transfer does not strongly depend on the air flow rate through the packed bed, the averaged equivalent mass transfer is governed by surface and pore diffusion in a particle of adsorbent at low flow rate. Moreover, the coefficient during the adsorption process is slightly larger than desorption. An equation of the overall mass transfer coefficient is derived. It shows five times as large as the value estimated by experiment. Therefore, the correlation and fitting parameters are presented for prediction of the overall heat and mass transfer coefficients. The estimation accuracy was improved.

  2. A Note on a Geometric Interpretation of the Correlation Coefficient.

    Science.gov (United States)

    Marks, Edmond

    1982-01-01

    An alternate geometric interpretation of the correlation coefficient to that given in most statistics texts for psychology and education is presented. This interpretation is considered to be more consistent with the statistical model for the data, and richer in geometric meaning. (Author)

  3. Methods for measuring diffusion coefficients of radon in building materials

    NARCIS (Netherlands)

    Cozmuta, [No Value; van der Graaf, ER

    2001-01-01

    Two methods for determining the Rn-222 diffusion coefficient in concrete are presented. Experimentally, the flush and adsorption technique to measure radon release rates underlines both methods. Theoretically, the first method was developed fur samples of cubical geometry. The radon diffusion equati

  4. On the first Townsend coefficient at high electric field

    OpenAIRE

    Davydov, Yu. I.

    2004-01-01

    Based on the simplified approach it is shown and experimentally confirmed that gas gain in wire chambers at very low pressure becomes higher on thicker wires at the same applied high voltage. This is a consequence of the fact that the first Townsend coefficient at high reduced electric field depends almost entirely on the mean free path of electrons.

  5. On the first Townsend coefficient at high electric field

    CERN Document Server

    Davydov, Y I

    2004-01-01

    For the first time it is shown and experimentally confirmed that gas gain in wire chambers at very low pressure become higher on thicker wires at the same applied high voltage. This is a consequence of the fact that the first Townsend coefficient at high reduced electric field depends almost entirely on the electron's mean free path.

  6. Distribution coefficient of plutonium between sediment and seawater

    International Nuclear Information System (INIS)

    Using plutonium 237 as a tracer, a series of experiments were conducted to determine the distribution coefficient of plutonium onto sediments both under oxic and anoxic conditions, where the plutonium was added to seawater in three different valence states: III, IV and VI

  7. Conformal anomaly c-coefficients of superconformal 6d theories

    CERN Document Server

    Beccaria, Matteo

    2015-01-01

    We propose general relations between the conformal anomaly and the chiral (R-symmetry and gravitational) anomaly coefficients in 6d (1,0) superconformal theories. The suggested expressions for the three type B conformal anomaly c-coefficients complement the expression for the type A anomaly a-coefficient found in arXiv:1506.03807. We check them on several examples -- the standard (1,0) hyper and tensor multiplets as well as some higher derivative short multiplets containing vector fields that generalize the superconformal 6d vector multiplet discussed in arXiv:1506.08727. We also consider a family of higher derivative superconformal (2,0) 6d multiplets associated to 7d multiplets in the KK spectrum of 11d supergravity compactified on S^4. In particular, we prove that (2,0) 6d conformal supergravity coupled to 26 tensor multiplets is free of all chiral and conformal anomalies. We discuss some interacting (1,0) superconformal theories, predicting the c-coefficients for the "E-string" theory on multiple M5-brane...

  8. Solving Second-Order Differential Equations with Variable Coefficients

    Science.gov (United States)

    Wilmer, A., III; Costa, G. B.

    2008-01-01

    A method is developed in which an analytical solution is obtained for certain classes of second-order differential equations with variable coefficients. By the use of transformations and by repeated iterated integration, a desired solution is obtained. This alternative method represents a different way to acquire a solution from classic power…

  9. A Study of Eddy Viscosity Coefficient in Numerical Tidal Simulation

    Institute of Scientific and Technical Information of China (English)

    陈永平; 雷智益

    2001-01-01

    Based on the fluid motion equations, the physical meaning of eddy viscosity coefficient and the rationality of theBoussinesq hypothesis are discussed in this paper. The effect of the coefficient on numerical stability is analyzed briefly.A semi-enclosed rectangular sea area, with an orthogonal spur dike, is applied in a 2-D numerical model to study the effect of horizontal eddy viscosity coefficient (AH). The computed result shows that AH has little influence on the tidal level and averaged flow velocity, but has obvious influence on the intensity and the range of return flow around near thespur dike. Correspondingly, a wind-driven current pool and an annular current are applied in a 3-D numerical modelrespectively to study the effect of vertical eddy viscosity coefficient (AV). The computed result shows that the absolute value of AV is inversely proportional to that of horizontal velocity, and the vertical gradient value of AV determines the ver-tical distribution of horizontal velocity. The distribution form of AV is theoretically recommended as a parabolic type, ofwhich the maximum value appears at 0.5 H.

  10. Estimation of bulk transfer coefficient for latent heat flux (Ce)

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.

    The bulk transfer coefficient for latent heat flux (Ce) has been estimated over the Arabian Sea from the moisture budget during the pre-monsoon season of 1988. The computations have been made over two regions (A: 0-8 degrees N: 60-68 degrees E: B: 0...

  11. Dissociation and Mass Transfer Coefficients for Ammonia Volatilization Models

    Science.gov (United States)

    Process-based models are being used to predict ammonia emissions from manure sources, but their accuracy has not been fully evaluated for cattle manure. Laboratory trials were conducted to measure the dissociation and mass transfer coefficients for ammonia volatilization from media of buffered ammon...

  12. Heat transfer coefficient between UO2 and Zircaloy-2

    International Nuclear Information System (INIS)

    This paper provides some experimental values of the heat-transfer coefficient between UO2 and Zircaloy-2 surfaces in contact under conditions of interfacial pressure, temperature, surface roughness and interface atmosphere, that are relevant to UO2/Zircaloy-2 fuel elements operating in pressurized-water power reactors. Coefficients were obtained from eight UO2/ Zircaloy-2 pairs in atmospheres of helium, argon, krypton or xenon, at atmosphere pressure and in vacuum. Interfacial pressures were varied from 50 to 550 kgf/cm2 while surface roughness heights were in the range 0.2 x 10-4 to 3.5 x 10-4 cm. The effect on the coefficients of cycling the interfacial pressure, of interface gas pressure and of temperature were examined. The experimental values of the coefficients were used to test the predictions of expressions for the heat-transfer between two solids in contact. For the particular UO2/ Zircaloy-2 pairs examined, numerical values were assigned to several parameters that related the surface roughnesses to either the radius of solid/solid contact spots or to the mean thickness of the interface voids and that accounted for the imperfect accommodation of the void gas on the test surfaces. (author)

  13. n-Alcohol/Water Partition Coefficients for Decachlorobiphenyl (PCB 209)

    Science.gov (United States)

    Measurements of n-octanol/water partition coefficients (Kow) for highly hydrophobic chemicals are extremely difficult and are rarely made, in part due to the large volumes of water typically needed to quantify these compounds in the aqueous phase. An extrapolation approach using ...

  14. Determination of the Static Friction Coefficient from Circular Motion

    Science.gov (United States)

    Molina-Bolívar, J. A.; Cabrerizo-Vílchez, M. A.

    2014-01-01

    This paper describes a physics laboratory exercise for determining the coefficient of static friction between two surfaces. The circular motion of a coin placed on the surface of a rotating turntable has been studied. For this purpose, the motion is recorded with a high-speed digital video camera recording at 240 frames s[superscript-1], and the…

  15. Load Coefficients on Grates used for Wind Turbine Access Platforms

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Rasmussen, Michael R.; Frigaard, Peter

    In this report is presented the results of tests carried out at Dept. of Civil Engineering, Aalborg University (AAU) on behalf of DONG Energy A/S and Vattenfall A/S, Denmark. The objective of the tests was to investigate the load coefficient on different platform grates and a solid plate...

  16. Approximation of the Frame Coefficients using Finite Dimensional Methods

    DEFF Research Database (Denmark)

    Christensen, Ole; Casazza, P.

    1997-01-01

    A frame is a family $\\{f_i \\}_{i=1}^{\\infty}$ of elements in aHilbert space $\\cal H $with the property that every element in $\\cal H $ can be written as a(infinite) linear combination of the frame elements. Frame theorydescribes how one can choose the corresponding coefficients, which arecalled...

  17. ANALYTIC SOLUTIONS OF MATRIX RICCATI EQUATIONS WITH ANALYTIC COEFFICIENTS

    NARCIS (Netherlands)

    Curtain, Ruth; Rodman, Leiba

    2010-01-01

    For matrix Riccati equations of platoon-type systems and of systems arising from PDEs, assuming the coefficients are analytic or rational functions in a suitable domain, analyticity of the stabilizing solution is proved under various hypotheses. General results on analytic behavior of stabilizing so

  18. Least squares estimation in a simple random coefficient autoregressive model

    DEFF Research Database (Denmark)

    Johansen, S; Lange, T

    2013-01-01

    The question we discuss is whether a simple random coefficient autoregressive model with infinite variance can create the long swings, or persistence, which are observed in many macroeconomic variables. The model is defined by yt=stρyt−1+εt,t=1,…,n, where st is an i.i.d. binary variable with p...

  19. Inelastic Neutron Scattering and Separation Coefficient of Absorbed Hydrogen

    DEFF Research Database (Denmark)

    Silvera, I. F.; Nielsen, Mourits

    1976-01-01

    Inelastic neutron scattering and measurement of the ortho-para separation coefficient have been used to study the low lying rotational states of molecular hydrogen adsorbed on activated alumina. The observations are consistent with a picture in which the orientational motion of the molecules is...

  20. Transport coefficients for driven granular mixtures at low density

    Science.gov (United States)

    Khalil, Nagi; Garzó, Vicente

    2013-11-01

    The transport coefficients of a granular binary mixture driven by a stochastic bath with friction are determined from the inelastic Boltzmann kinetic equation. A normal solution is obtained via the Chapman-Enskog method for states near homogeneous steady states. The mass, momentum, and heat fluxes are determined to first order in the spatial gradients of the hydrodynamic fields, and the associated transport coefficients are identified. They are given in terms of the solutions of a set of coupled linear integral equations. As in the monocomponent case, since the collisional cooling cannot be compensated for locally by the heat produced by the external driving, the reference distributions (zeroth-order approximations) fi(0) (i=1,2) for each species depend on time through their dependence on the pressure and the temperature. Explicit forms for the diffusion transport coefficients and the shear viscosity coefficient are obtained by assuming the steady-state conditions and by considering the leading terms in a Sonine polynomial expansion. A comparison with previous results obtained for granular Brownian motion and by using a (local) stochastic thermostat is also carried out. The present work extends previous theoretical results derived for monocomponent dense gases [Garzó, Chamorro, and Vega Reyes, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.87.032201 87, 032201 (2013)] to granular mixtures at low density.

  1. Measurement of the convective heat-transfer coefficient

    CERN Document Server

    Conti, Rosaria; Fiordilino, Emilio

    2014-01-01

    We propose an experiment for investigating how objects cool down toward the thermal equilibrium with its surrounding through convection. We describe the time dependence of the temperature difference of the cooling object and the environment with an exponential decay function. By measuring the thermal constant tau, we determine the convective heat-transfer coefficient, which is a characteristic constant of the convection system.

  2. SOME ASPECTS OF MOTOR CAR COERCION COEFFICIENT DETERMINATION

    Directory of Open Access Journals (Sweden)

    О. Denysenko

    2010-01-01

    Full Text Available A short review of motor car coercion coefficient determination is presented. The models designed for the determination of motor car queues time intervals at the stop line is presented. The estimation of modeling results according to experimental data is carried out.

  3. The unique solution of stochastic differential equations with independent coefficients

    OpenAIRE

    Ryter, Dietrich

    2014-01-01

    SDE's must be solved in the "anti-Ito" sense when their coefficients are independent. While the "noise-induced drift" matters for the sample paths, it is absent in the Fokker-Planck equation, which takes a particularly simple form and is invariant under changes of the variables. Pure noise yields martingale solutions.

  4. Simplified Models for the Drag Coefficient of a Pitched Baseball

    Science.gov (United States)

    Kagan, David; Nathan, Alan M.

    2014-01-01

    The classic experiment to measure the drag coefficient involves dropping coffee filters. Wouldn't it be more fun to try something different? In fact, an experiment on the drag force is conducted nearly 4000 times a day during the baseball season and you have free access to this PITCHf/x data!

  5. Lifshitz Tails for the Interband Light Absorption Coefficient

    Indian Academy of Sciences (India)

    W Kirsch; M Krishna

    2010-09-01

    In this paper we consider the interband light absorption coefficient (ILAC) for various models. We show that at the lower and upper edges of the spectrum the Lifshitz tails behaviour of the density of states implies similar behaviour for the ILAC at appropriate energies. The Lifshitz tails property is also exhibited at some points corresponding to the internal band edges of the spectrum.

  6. Adaptive Finite Element Methods for Elliptic Problems with Discontinuous Coefficients

    KAUST Repository

    Bonito, Andrea

    2013-01-01

    Elliptic PDEs with discontinuous diffusion coefficients occur in application domains such as diffusions through porous media, electromagnetic field propagation on heterogeneous media, and diffusion processes on rough surfaces. The standard approach to numerically treating such problems using finite element methods is to assume that the discontinuities lie on the boundaries of the cells in the initial triangulation. However, this does not match applications where discontinuities occur on curves, surfaces, or manifolds, and could even be unknown beforehand. One of the obstacles to treating such discontinuity problems is that the usual perturbation theory for elliptic PDEs assumes bounds for the distortion of the coefficients in the L∞ norm and this in turn requires that the discontinuities are matched exactly when the coefficients are approximated. We present a new approach based on distortion of the coefficients in an Lq norm with q < ∞ which therefore does not require the exact matching of the discontinuities. We then use this new distortion theory to formulate new adaptive finite element methods (AFEMs) for such discontinuity problems. We show that such AFEMs are optimal in the sense of distortion versus number of computations, and report insightful numerical results supporting our analysis. © 2013 Societ y for Industrial and Applied Mathematics.

  7. On the misinterpretation of the correlation coefficient in pharmaceutical sciences

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn

    2006-01-01

    The correlation coefficient is often used and more often misused as a universal parameter expressing the quality in linear regression analysis. The popularity of this dimensionless quantity is evident as it is easy to communicate and considered to be unproblematic to comprehend. However, illustra...

  8. On Polynomial Solutions of Linear Differential Equations with Polynomial Coefficients

    Science.gov (United States)

    Si, Do Tan

    1977-01-01

    Demonstrates a method for solving linear differential equations with polynomial coefficients based on the fact that the operators z and D + d/dz are known to be Hermitian conjugates with respect to the Bargman and Louck-Galbraith scalar products. (MLH)

  9. PENGARUH PENGUNGKAPAN CORPORATE SOCIAL RESPONSIBILITY TERHADAP EARNING RESPONSE COEFFICIENT

    Directory of Open Access Journals (Sweden)

    MI Mitha Dwi Restuti

    2012-03-01

    Full Text Available Tujuan penelitian ini adalah untuk mengetahui pengaruh negatif pengungkapan Corporate Sosial Responsibility (CSR disclosure terhadap Earning Response Coefficient (ERC. Alat analisis yang digunakan dalam penelitian ini menggunakan metode analisis regresi berganda.Sampel yang digunakan adalah sebanyak 150 perusahaan yang terdaftar pada Bursa Efek Indonesia pada tahun 2010. Berdasarkan hasil penelitian ditemukan bahwa pengungkapan Corporate Social Responsibility tidak berpengaruh terhadap Earning Response Coefficient (ERC. Hal ini dapat dikatakan bahwa investor belum memperhatikan informasi-informasi sosial yang diungkapkan dalam laporan tahunan perusahaan sebagai informasi yang dapat mempengaruhi investor dalam melakukan keputusan investasi. Investor masih mengganggap informasi laba lebih bermanfaat dalam menilai perusahaan dan dianggap lebih mampu memberikan informasi untuk mendapatkan return saham yang diharapkan oleh investor dibandingkan dengan informasi sosial yang diungkapkan oleh perusahaan.The purpose of this study is to determine the negative effect of Corporate Social Responsibility disclosure (CSR disclosure of Earnings Response Coefficient (ERC. Multiple regressions were used to analyze the data. The samples were 150 companies listed on the Indonesia Stock Exchange in 2010. Based on the research, the result was the disclosures of Corporate Social Responsibility did not influence Earning Response Coefficient (ECR. It can be said that investors did not pay attention to social information that was disclosed in the company’s annual report as information that could affect investors in making investment decisions. Investor did not consider sosial information; they only consider profit information to assess the company value and their investment return

  10. Melanoidins extinction coefficient in the glucose/glycine Maillard reaction

    NARCIS (Netherlands)

    Martins, S.I.F.S.; Boekel, van M.A.J.S.

    2003-01-01

    Melanoidins (brown, nitrogenous polymers and co-polymers) are the final products of the Maillard reaction. The glucose/glycine melanoidins extinction coefficient was determined using C-14-labelled glucose at three different reaction conditions. The absorbance was measured at different wavelengths (4

  11. Musical Instrument Identification using Multiscale Mel-frequency Cepstral Coefficients

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Morvidone, Marcela; Daudet, Laurent

    2010-01-01

    We investigate the benefits of evaluating Mel-frequency cepstral coefficients (MFCCs) over several time scales in the context of automatic musical instrument identification for signals that are monophonic but derived from real musical settings. We define several sets of features derived from MFCCs...

  12. Regularity of Solutions to Elliptic Equations with VMO Coefficients

    Institute of Scientific and Technical Information of China (English)

    Ye Min CHEN

    2004-01-01

    The aim of this paper is to study the regularity of solutions to the Dirichlet problems for general second-order elliptic equations in Lebesgue and Morrey spaces. We consider both nondivergence and divergence forms and the coefficients of principle terms are assumed to be in VMO.

  13. Nuclear-matter symmetry coefficient and nuclear masses

    CERN Document Server

    Pearson, J M

    2000-01-01

    Within the framework of the ETFSI (extended Thomas-Fermi plus Strutinsky integral) mass formula, a precision fit of nuclear masses with Skyrme forces, subject to the constraint that neutron matter does not collapse at nuclear or subnuclear densities, is possible if, but only if, the nuclear-matter symmetry coefficient J lies close to 28 MeV.

  14. High-Order Dispersion Coefficients for Alkali-metal Atoms

    Institute of Scientific and Technical Information of China (English)

    KANG Shuai; DING Chi-Kun; CHEN Chang-Yong; WU Xue-Qing

    2013-01-01

    High-order dispersion coefficients C9,C11,C12,and C13 for the ground-state alkali-metals were calculated by combining the l-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions.The results were compared.

  15. Temperature and Coefficient of Restitution of a Table Tennis Ball

    Directory of Open Access Journals (Sweden)

    Yoonyoung Chang

    2016-01-01

    Full Text Available The coefficient of restitution (COR of a bouncing table tennis ball was measured at varying ball temperatures with a Motion Detector. It was found that there is a negative linear relationship between the COR and the temperature of the table tennis ball for temperatures ranging from 5 to 56 ̊C.

  16. A correlation for heat transfer coefficients in food extruders.

    Science.gov (United States)

    Levine, L; Rockwood, J

    1986-06-01

    A dimensionless correlation of heat transfer coefficient for heat flow between the extruder barrel wall and extrudate is presented. The standard error of estimate of the correlation is 12.4%. The correlation is useful for the design and scale-up of food extruders and the design of associated temperature control systems.

  17. Consumptive Water Use and Crop Coefficients of Irrigated Sunflower

    Science.gov (United States)

    In semi-arid environments, the use of irrigation is necessary for sunflower production to reach its maximum potential. The aim of this study was to quantify the consumptive water use and crop coefficients of irrigated sunflower (Helianthus annuus L.) without soil water limitations during two growing...

  18. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    Science.gov (United States)

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast.

  19. Measurements of gaseous multiplication coefficient in pure isobutane

    International Nuclear Information System (INIS)

    In this work it is presented measurements of gaseous multiplication coefficient (α) in pure isobutane obtained with a parallel plate chamber, protected against discharges by one electrode (anode) of high resistivity glass (ρ = 2 x 1012Ω.cm). The method applied was the Pulsed Townsend, where the primary ionization is produced through the incidence of a nitrogen laser beam onto a metallic electrode (cathode). The electric currents measured with the chamber operating in both ionization and avalanche regimes were used to calculate the gaseous multiplication coefficient by the solution of the Townsend equation for uniform electric fields. The validation of the technique was provided by the measurements of gaseous multiplication coefficient in pure nitrogen, a widely studied gas, which has well-established data in literature. The α coefficients in isobutane were measured as a function of the reduced electric field in the range of 139Td up to 208Td. The obtained values were compared with those simulated by Imonte software (version 4.5) and the only experimental results available in the literature, recently obtained in our group. This comparison showed that the results are concordant within the experimental errors. (author)

  20. Minimum Ballistic Factor Missile Shapes For Variable Skin Friction Coefficient

    Directory of Open Access Journals (Sweden)

    S. C. Jain

    1973-10-01

    Full Text Available Minimum ballistic factor for slender axisymmetric power law bodies have been obtained by taking a variable skinfriction coefficient for the cases when any two of the three quantities length, diameter and surface area have been pre-prescribed.