Clebsch-Gordan coefficients for symmetric representations of symplectic groups
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Method of generating invariants for symplectic groups is formulated. The Clebsch-Gordan coefficients for coupling of symmetric representations D(PO..., O) of groups Sp(2N) were calculated and their symmetry properties were obtained
New information and entropic inequalities for Clebsch-Gordan coefficients
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
Clebsch--Gordan Coefficients of the Quaternion Group
Mathar, Richard J.
2010-01-01
The Clebsch--Gordan coefficients of the Kronecker products of the irreducible representations of the Quaternion Group Q8, of the Generalized Quaternion Groups Q16 and Q32, and of the factor group (Q32 X Q32)/{(1,1),(-1,-1)} are computed as eigenvectors of a well-known matrix of triple-products of the irreducible representations.
A simple method for calculating Clebsch-Gordan coefficients
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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.
Summation free expression for some special Clebsch-Gordan coefficients
International Nuclear Information System (INIS)
The known general formula for the Clebsch-Gordan coefficients of the 3-dimensional rotation group involves one summation which results in explicit summation-free expressions for the coefficients where either one of the angular momenta is the sum of the other two or the magnetic quantum number corresponding to one of the angular momenta takes its maximum value in magnitude. By using very different techniques, explicit expressions for the coefficients 1,0;j2,0|j,0>,2,-1/2|j,0> are also obtained, where the integral or half-integral nature of the j's is indicated by the magnetic quantum number involved. Here the expressions depend upon whether j1+j2+j is an even or an odd integer. For these coefficients, the magnetic quantum numbers involved take their minimum value in magnitude. By using the recursion relation for the coefficients of the form 1,m,j2,-m,|j,0>, we can calculate these coefficients in terms of the above known ones provided we also have the explicit value of the coefficient 1,1;j2,-1|j,0> where j1+j2+j is an odd integer. (The recursion relation for these coefficients in terms of 1,0;j2,0|j,0> becomes a triviality since 1,0;j2,0|j,0> vanishes when j1+j2+j is an odd integer.) Our main purpose in this paper is to give an explicit expression for the coefficients 1,1;j2,-1|j,0> where j1+j2+j is an odd integer. We are able to arrive at our expression by using a complicated transformation between hypergeometric functions which seems to have been neglected so far. For the coefficients where the magnetic quantum numbers have their minimum value in magnitude, this transformed expression becomes summation free and we obtain explicit values of the three already known coefficients and the fourth so far unknown. We believe that further study of this transformation may be useful on its own because it provides a link between very different types of expressions. (author)
Tables of Clebsch-Gordan coefficients adapted to the cubical, tetragonal and digonal double groups
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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
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
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
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).
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.
The algebra of dual -1 Hahn polynomials and the Clebsch-Gordan problem of sl_{-1}(2)
Genest, Vincent X.; Vinet, Luc; Zhedanov, Alexei
2012-01-01
The algebra H of the dual -1 Hahn polynomials is derived and shown to arise in the Clebsch-Gordan problem of sl_{-1}(2). The dual -1 Hahn polynomials are the bispectral polynomials of a discrete argument obtained from a q-> -1 limit of the dual q-Hahn polynomials. The Hopf algebra sl_{-1}(2) has four generators including an involution, it is also a q-> -1 limit of the quantum algebra sl_{q}(2) and furthermore, the dynamical algebra of the parabose oscillator. The algebra H, a two-parameter ge...
International Nuclear Information System (INIS)
The new averaged definite parity j/sub z/(ADPj/sub z/) approximation is considered in detail from the standpoint of the exact body frame CC cross section equations. These cross section equations are decomposed into contributions from the various possible orbital angular momenta and projections of the total angular momentum j onto the scattering vector. This decomposition then permits a clearer examination of the quantities actually approximated in j/sub z/-conserving approximations. The previously obtained constant weight version is compared to the present Clebsch--Gordan weight version by applying both to He+H2 collisions. Results for definite parity partial cross sections and integral cross sections are used as the basis of the comparison
Van der Waerden invariant and Wigner coefficients for some compact groups
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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)
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.
Calculations of angular momentum coupling coefficients on a computer code
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In this study, Clebsch-Gordan coefficients, 3j symbols, Racah coefficients, Wigner's 6j and 9j symbols were calculated by a prepared computer code of COEFF. The computer program COEFF is described which calculates angular momentum coupling coefficients and expresses them as quotient of two integers multiplied by the square root of the quotient of two integers. The program includes subroutines to encode an integer into its prime factors, to decode of prime factors back into an integer , to perform basic arithmetic operations on prime-coded numbers, as well as subroutines which calculate the coupling coefficients themselves. The computer code COEFF had been prepared to run on a VAX. In this study we rearranged the code to run on PC and tested it successfully. The obtained values in this study, were compared with the values of other computer programmes. A pretty good agreement is obtained between our prepared computer code and other computer programmes
The role of SU(2) 3n-j coefficients in SU(3)
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The irreducible representations of the group SU(3) may be given completely in terms of the 3-j, 6-j, and 9-j coefficients of SU(2). More remarkably these same coefficients, and the 12-j coefficients as well, enter into the description of a large class of Clebsch-Gordan (C-G) coefficients for the group SU(3), this occurrence going beyond that in the well-known group-subgroup reduction SU(3)↓U(2). The problem of determining the SU(3) irreducible representations and its C-G coefficients is reviewed, and it is shown how the SU(2) quantities enter into the SU(3) problem in special cases
New algebraic tables of SU(2) quantities
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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)
Tables of SU(3) isoscalar factors
International Nuclear Information System (INIS)
The Clebsch-Gordan coefficients of SU(3) are useful in calculations involving baryons and mesons, as well as in calculations involving arbitrary numbers of quarks. For the latter case, one needs the coupling constants between states of nonintegral hypercharges. The existing published tables are insufficient for many such applications, and therefore we have compiled this collection. This report supplies the isoscalar factors required to reconstruct the Clebsch-Gordan coefficients for a large set of products of representations
Some aspects of q- and qp- boson calculus
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A set of compatible formulas for the Clebsch-Gordan coefficients of the quantum algebra Uq(su2) is given in this paper. These formulas are q-deformations of known formulas, as for instance: Wigner, van der Waerden, and Racah formulas. They serve as starting points for deriving various realizations of the unit tensor of Uq(su2) in terms of q-boson operators. the passage from the one-parameter quantum algebra Uq(su2) to the two-parameter quantum algebra Uqp(u2) is discussed at the level of Clebsch-Gordan coefficients. (authors)
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.
Rotations and angular momentum
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This paper is devoted to the analysis of rotational invariance and the properties of angular momentum in quantum mechanics. In particular, the problem of addition of angular momenta is treated in detail, and tables of Clebsch-Gordan coefficients are included
Construction of SU(3) irreps in canonical SO(3)-coupled bases
Czech Academy of Sciences Publication Activity Database
Rowe, D. J.; Thiamová, Gabriela
2008-01-01
Roč. 41, č. 6 (2008), 065206/1-065206/9. ISSN 1751-8113 Institutional research plan: CEZ:AV0Z10480505 Keywords : CLEBSCH-GORDAN-COEFFICIENT * NUCLEAR SHELL MODEL * SO(3) BASE S Subject RIV: BE - Theoretical Physics Impact factor: 1.540, year: 2008
Generalized Uncertainty Principle and Angular Momentum
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.
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
Minisuperspace limit of the AdS3 WZNW model
Ribault, Sylvain
2009-01-01
We derive the three-point function of the AdS3 WZNW model in the minisuperspace limit by Wick rotation from the H3+ model. The result is expressed in terms of Clebsch-Gordan coefficients of the Lie algebra sl(2,R). We also introduce a covariant basis of functions on AdS3, which can be interpreted as bulk-boundary propagators.
The Demazure-Tits subgroup of a simple Lie group
Michel, L.; Patera, J.; Sharp, R. T.
1988-04-01
The Demazure-Tits subgroup of a simple Lie group G is the group of invariance of Clebsch-Gordan coefficients tables (assuming an appropriate choice of basis). The structure of the Demazure-Tits subgroups of An, Bn, Cn, Dn, and G2 is described. Orbits of the permutation action of the DT group in any irreducible finite-dimensional representation space of A2, C2, and G2 are decomposed into the sum of irreducible representations of the DT group.
Invariants, Projection Operators and $SU(N)\\times SU(N)$ Irreducible Schwinger Bosons
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.
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.
Self-dual continuous series of representations for Uq(sl(2)) and Uq(osp(1 vertical stroke 2))
International Nuclear Information System (INIS)
We determine the Clebsch-Gordan and Racah-Wigner coefficients for continuous series of representations of the quantum deformed algebras Uq(sl(2)) and Uq(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.
Addition theorems for spin spherical harmonics: I. Preliminaries
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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).
Strong interactions, Zweig's rule, and weaker interactions
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An attempt is made to connect five notions: Strong interaction scattering amplitudes do not involve the action of a Hamiltonian and are only Clebsch-Gordan coefficients. The four momentum vector P is an SU(something) operator. The four momentum of a quark does not change in a strong interaction scattering. Zweig's rule. Gluons should not be drawn in strong interaction scattering diagrams. Finally, a simple explanation will be offered for the weak interaction of leptons amongst themselves and with hadrons. (U.S.)
Small antiferromagnetic spin systems-Sublattice Hamiltonians
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A few examples of four-spin Heisenberg systems with dominant antiferromagnetic couplings are considered. All systems can be described by the so-called sublattice Hamiltonian H=SA.SB or its modifications, where SX is the total spin of a sublattice X=A, B. In such a case (eigen)energies are simple functions of the total spin number S, total spins of sublattices SA, SB, and the Hamiltonian parameters (ratios of exchange integrals). Moreover, eigenstates are strictly determined by a coupling scheme assumed and the appropriate Clebsch-Gordan coefficients. In this sense the systems considered are classical ones.
Angular analyses in relativistic quantum mechanics
International Nuclear Information System (INIS)
This work describes the angular analysis of reactions between particles with spin in a fully relativistic fashion. One particle states are introduced, following Wigner's method, as representations of the inhomogeneous Lorentz group. In order to perform the angular analyses, the reduction of the product of two representations of the inhomogeneous Lorentz group is studied. Clebsch-Gordan coefficients are computed for the following couplings: l-s coupling, helicity coupling, multipolar coupling, and symmetric coupling for more than two particles. Massless and massive particles are handled simultaneously. On the way we construct spinorial amplitudes and free fields; we recall how to establish convergence theorems for angular expansions from analyticity hypothesis. Finally we substitute these hypotheses to the idea of 'potential radius', which gives at low energy the usual 'centrifugal barrier' factors. The presence of such factors had never been deduced from hypotheses compatible with relativistic invariance. (author)
Relativistic quantum mechanics
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...
Field operators for anyons and plektons
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Given its superselection sectors with non-abelian braid group statistics, we extend the algebra A of local observables into an algebra F containing localized intertwiner fields which carry the superselection charges. The construction of the inner degrees of freedom, as well as the study of their transformation properties (quantum symmetry), are entirely in terms of the superselection structure of the observables. As a novel and characteristic feature for braid group statistics, Clebsch-Gordan and commutation 'coefficients' generically take values in the algebra M of symmetry operators, much as it is the case with quasi-Hopf symmetry. A, F, and M are all C* algebras, i.e. represented by bounded operators on a Hilbert space with positive metric. (orig.)
Multipole expansions in four-dimensional hyperspherical harmonics
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The technique of vector differentiation is applied to the problem of the derivation of multipole expansions in four-dimensional space. Explicit expressions for the multipole expansion of the function rnCj(r-circumflex) with r = r1 + r2 are given in terms of tensor products of two hyperspherical harmonics depending on the unit vectors r-circumflex1 and r-circumflex2. The multipole decomposition of the function (r1 . r2)n is also derived. The proposed method can be easily generalized to the case of the space with dimensionality larger than four. Several explicit expressions for the four-dimensional Clebsch-Gordan coefficients with particular values of parameters are presented in the closed form
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.
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)
Energy Technology Data Exchange (ETDEWEB)
Moussa, P. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires
1968-06-01
This work describes the angular analysis of reactions between particles with spin in a fully relativistic fashion. One particle states are introduced, following Wigner's method, as representations of the inhomogeneous Lorentz group. In order to perform the angular analyses, the reduction of the product of two representations of the inhomogeneous Lorentz group is studied. Clebsch-Gordan coefficients are computed for the following couplings: l-s coupling, helicity coupling, multipolar coupling, and symmetric coupling for more than two particles. Massless and massive particles are handled simultaneously. On the way we construct spinorial amplitudes and free fields; we recall how to establish convergence theorems for angular expansions from analyticity hypothesis. Finally we substitute these hypotheses to the idea of 'potential radius', which gives at low energy the usual 'centrifugal barrier' factors. The presence of such factors had never been deduced from hypotheses compatible with relativistic invariance. (author) [French] On decrit un formalisme permettant de tenir compte de l'invariance relativiste, dans l'analyse angulaire des amplitudes de reaction entre particules de spin quelconque. Suivant Wigner, les etats a une particule sont introduits a l'aide des representations du groupe de Lorentz inhomogene. Pour effectuer les analyses angulaires, on etudie la reduction du produit de deux representations du groupe de Lorentz inhomogene. Les coefficients de Clebsch-Gordan correspondants sont calcules dans les couplages suivants: couplage l-s couplage d'helicite, couplage multipolaire, couplage symetrique pour plus de deux particules. Les particules de masse nulle et de masse non nulle sont traitees simultanement. Au passage, on introduit les amplitudes spinorielles et on construit les champs libres, on rappelle comment des hypotheses d'analyticite permettent d'etablir des theoremes de convergence pour les
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
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
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...
Conformal invariant two particle processes
International Nuclear Information System (INIS)
For the conformal group (essentially the SO2(n,2)group) in n-dimensional Minkowsi-space homogeneous spaces are studied which can be interpreted as 2-particle configuration spaces, and 2-particle representations are induced (both participants are spin 0 particles). The eigensolutions of the Casimir-operator in momentum space are Clebsch-Gordan coefficients in momentum basis. The separation of a complete set of comuting operators from the Casimir eigenvalue equations results in all cases in differential equations with 2 variables (a direct consequence of the rank 2 of the homogen spaces), which can be classified as 'generalized hypergeometric differential operators in 2 variables' (this type, as the author supposes, has not been delt with in the literature so far). In the second part the classical conform invariant (relativistic) 2-particle problem, corresponding to the common quantum mechanical (or quantum field theoretical) problem, is presented and solved completely. It is shown for example that for participant momentums (reasonable in the classic sens) on the forward - or on the zero cone only scattering and no bound states are found. (orig./WBU)
Double groups and projective representations
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.
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 ...
A SUSY SU(5)xT' Unified Model of Flavour with large \\theta_{13}
Meroni, Aurora; Spinrath, Martin
2012-01-01
We present a SUSY SU(5)xT' unified flavour model with type I see-saw mechanism of neutrino mass generation, which predicts the reactor neutrino angle to be \\theta_{13} = 0.14 close to the recent results from the Daya Bay and RENO experiments. The model predicts also values of the solar and atmospheric neutrino mixing angles, which are compatible with the existing data. The T' breaking leads to tri-bimaximal mixing in the neutrino sector, which is perturbed by sizeable corrections from the charged lepton sector. The model exhibits geometrical CP violation, where all complex phases have their origin from the complex Clebsch-Gordan coefficients of T'. The values of the Dirac and Majorana CP violating phases are predicted. For the Dirac phase in the standard parametrisation of the neutrino mixing matrix we get a value close to 90 degrees \\delta = \\pi/2 - 0.45 \\theta^c = 84.3 degrees, \\theta^c being the Cabibbo angle. The neutrino mass spectrum can be with normal ordering (2 cases) or inverted ordering. In each ca...
A Minimal Model of Neutrino Flavor
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...
International Nuclear Information System (INIS)
This work demonstrates that the quantum mechanical moments of a state described by the density matrix correspond to discrete spherical harmonic moments of the classical multipole expansion of the spatial distribution of the angular momentum vectors. For the diagonal density matrix elements, this work exploits the fact that the quantum mechanical vector coupling (Clebsch-Gordan) coefficients become increasingly accurate discrete representations of spherical harmonics as j increases. A Schwinger-type basis accounts for nonaxially symmetric angular distributions, which result in nonzero off-diagonal elements of the density matrix. The resulting discrete minimum uncertainty picture of the classical moments has a stringent equivalence with the quantum mechanical one for all j and provides an unambiguous connection for the classical and quantum moments in the large j limit. The equivalence is numerically tested for simple models, and there is a satisfying equivalence even for small j. Applications, implications, and extensions are indicated, and the relevance of this work for the interpretation of classical mechanical simulations of inelastic and reactive molecular collisions will be documented elsewhere
Population dynamics in a metastable neon magneto-optical trap
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
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
Coefficients for Interrater Agreement.
Zegers, Frits E.
1991-01-01
The degree of agreement between two raters rating several objects for a single characteristic can be expressed through an association coefficient, such as the Pearson product-moment correlation. How to select an appropriate association coefficient, and the desirable properties and uses of a class of such coefficients--the Euclidean…
On the relation between the modular double of Uq(sl(2,R)) and the quantum Teichmueller theory
International Nuclear Information System (INIS)
We exhibit direct relations between the modular double of Uq(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 Uq(sl(2,R)).
Constellations and projective classical groups
International Nuclear Information System (INIS)
The constellation concept is recalled (geometrical description of a ray in a vector space). The groups PO(n + 1, C) or PSp(n + 1, C) are shown to preserve 'harmonic conjugation' between two constellations. The action of the Lorentz subgroup and its rotation subgroup is described. Finally, a theorem concerning Clebsch-Gordan product of constellations is proved. (orig.)
The projective Lie algebra of the Lorentz group and homographic transformations
International Nuclear Information System (INIS)
The Lorentz group is used as the group of homographic transformations on the Riemann sphere. Its Lie algebra is shown to have a very simple interpretation with the aid of cross products and constellation formalism. This property is used to give a constellation description of the Clebsch-Gordan series for the product of two states of spin 1
Transport Coefficients of Fluids
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.
The Randomized Dependence Coefficient
Lopez-Paz, David; Hennig, Philipp; Schölkopf, Bernhard
2013-01-01
We introduce the Randomized Dependence Coefficient (RDC), a measure of non-linear dependence between random variables of arbitrary dimension based on the Hirschfeld-Gebelein-R\\'enyi Maximum Correlation Coefficient. RDC is defined in terms of correlation of random non-linear copula projections; it is invariant with respect to marginal distribution transformations, has low computational cost and is easy to implement: just five lines of R code, included at the end of the paper.
Do Fresnel coefficients exist?
Felbacq, D; Guizal, B.; F Zolla
2001-01-01
The starting point of the article is the puzzling fact that one cannot recover the Fresnel coefficients by letting tend the width of a slab to infinity. Without using the so-called limiting absorption principle, we show by a convenient limit analysis that it is possible to define rigorously the field diffracted by a semi-infinite periodic medium.
Denominator function for canonical SU(3) tensor operators
International Nuclear Information System (INIS)
The definition of a canonical unit SU(3) tensor operator is given in terms of its characteristic null space as determined by group-theoretic properties of the intertwining number. This definition is shown to imply the canonical splitting conditions used in earlier work for the explicit and unique (up to +- phases) construction of all SU(3) WCG coefficients (Wigner--Clebsch--Gordan). Using this construction, an explicit SU(3)-invariant denominator function characterizing completely the canonically defined WCG coefficients is obtained. It is shown that this denominator function (squared) is a product of linear factors which may be obtained explicitly from the characteristic null space times a ratio of polynomials. These polynomials, denoted G/sup t//sub q/, are defined over three (shift) parameters and three barycentric coordinates. The properties of these polynomials (hence, of the corresponding invariant denominator function) are developed in detail: These include a derivation of their degree, symmetries, and zeros. The symmetries are those induced on the shift parameters and barycentric coordinates by the transformations of a 3 x 3 array under row interchange, column interchange, and transposition (the group of 72 operations leaving a 3 x 3 determinant invariant). Remarkably, the zeros of the general G/sup t//sub q/ polynomial are in position and multiplicity exactly those of the SU(3) weight space associated with irreducible representation [q-1,t-1,0]. The results obtained are an essential step in the derivation of a fully explicit and comprehensible algebraic expression for all SU(3) WCG coefficients
The Truth About Ballistic Coefficients
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.
Supersymmetry generators of arbitrary spin
International Nuclear Information System (INIS)
The infinitesimal generators of supersymmetry and translation form a solvable invariant subalgebra of the full graded Lie algebra. In O'Raifeartaigh's classification scheme this belongs to Case (iii). In general, the degree-n supersymmetry generators may be defined by requiring their nth derived algebra to be equal to translations. Degree-1 supersymmetries are studied for which S/subi/,S/subj/ = c (α/sup mu/C)/subi//subj/P/sub mu/, where a graded commutator is used. Supposing that ]S/subi/] belongs to some representation of the Lorentz group, the conditions on α/sup mu/ and C which result from Jacobi identities and Hermitian conjugation are studied. For the three-dimensional case the conditions are satisfied if (α/subk/C)/subi//subj/ is chosen to be a Clebsch-Gordan coefficient. This allows S to have any spin not-equal 0 and also gives the correct spin-statistics connection (grading). In the four-dimensional case it is shown how the problem is related to that of finding Lagrangian densities L/subk/ = ipsi-barα/sup mu/partial/sub mu/psi and L/subm/ = psi-barpsi, which are Hermitian scalars. There are an infinite number of possible representations to which S/subi/ can belong, including those of Bhabha type, for which the spin-statistics connection comes naturally from the representation. At the same time there can be supersymmetry generators of several different spins. The Volkov-Akulov nonlinear realization works in all cases and a supersymmetry-invariant Lagrangian can be constructed. Anticommutators seem to be important only in the sense that then finite-dimensional linear realizations can exist
International Nuclear Information System (INIS)
The spin correlations ωrz, r=1,2,3, and the probability pN of finding a system in the Neel state for the antiferromagnetic ring Fe6III (the so-called 'small ferric wheel') are calculated. States with magnetization M=0 and total spin 0≤S≤15, labeled by two (out of four) one-dimensional irreducible representations (irreps) of the point symmetry group D6, are taken into account. This choice follows from importance of these irreps in analyzing low-lying states in each S multiplet. Taking into account the Clebsch-Gordan coefficients for coupling total spins of sublattices (SA=SB=(15/2)) the global Neel probability pN* can be determined. Dependences of these quantities on state energy (per bond and in the units of exchange integral J) and the total spin S are analyzed. Providing we have determined pN(S), etc., for other antiferromagnetic rings (Fe10, for instance) we could try to approximate results for the largest synthesized ferric wheel Fe18. Since thermodynamic properties of Fe6 have been investigated recently, in the present considerations they are not discussed, but only used to verify obtained values of eigenenergies. Numerical results are calculated with high precision using two main tools: (i) thorough analysis of symmetry properties including methods of algebraic combinatorics and (ii) multiple precision arithmetic library GMP. The system considered yields more than 45 000 basic states (the so-called Ising configurations), but application of the method proposed reduces this problem to 20-dimensional eigenproblem for the ground state (S=0). The largest eigenproblem has to be solved for S=4; its dimension is 60. These two facts (high precision and small resultant eigenproblems) confirm the efficiency and usefulness of such an approach, so it is briefly discussed here
Photoelectron angular distribution and photoionization cross sections for H2
International Nuclear Information System (INIS)
Photoionization of H2 from its ground 1μ/sub g/+ state is studied theoretically. The rotational quantization is introduced in addition to the conventional vibrational-electronic transitions during the photoionization process. The photoionization differential cross section of this rotating system is derived and proved to be expressible in the simple form of [sigma(v')/4π][1 + #betta#(v')P2(cos theta)] for H2+ in the vibrational level v' or in the well-known form of (sigma/sub T//4π) [1 + #betta#P2(cos theta)] after summing over all of the vibrational levels of H2+. The angle theta of the ejected electron is measured from the polarization direction of the radiation for the linearly polarized light or measured from the light propagation direction for the unpolarized light. The asymmetry parameters #betta#(v') and #betta#, which are expressed explicitly here in terms of Racah and Clebsch-Gordan coefficients and electronic transition moments, are shown to equal approximately to 2 for the case of linearly polarized light and -1 for the case of unpolarized light. The differential cross section is also proved to be independent of the initial rotational quantum number N'' (of H2) by neglecting vibrational-rotational interactions. Using single-center electronic wave functions for both the molecular system and the outgoing electron and including partial waves l = 1, 3 and 5 in the continuum (Coulomb) wave functions, sigma(v') and #betta#(v') are computed as a function of v' at 584 A. The calculated ratios sigma(v')/sigma(v'=2) agree with the measured vibrational intensity distributions. sigma/sub T/ and #betta# are computed in the incident photon energy range of 600 A to 440 A and the results compare favorably with previous calculations
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.
Converting Sabine absorption coefficients to random incidence absorption coefficients
DEFF Research Database (Denmark)
Jeong, Cheol-Ho
2013-01-01
Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a sample and non-uniform intensity in the reverberation chambers under test. In this study, conversion methods from Sabine absorption...... coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations...
On the Kendall Correlation Coefficient
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 ...
WEIR COEFFICIENT FOR CYLINDRICAL WEIRS
Directory of Open Access Journals (Sweden)
Senayi DÖNMEZ
2002-01-01
Full Text Available In this study, the weir coefficient for cylindrical weirs was experimentally investigated. Experiments were conducted for both free and submerged overflow conditions. Experimental results have indicated that the weir coefficient is about 3.50-3.80 for the free overflow condition. The weir coefficient for the submerged overflow condition varies with the amount of submergence.
Transfer coefficients for terrestrial foodchains
International Nuclear Information System (INIS)
Transfer coefficients to predict the passage of isotopes from the environment to terrestrial foods have been derived for various radionuclides of importance in the nuclear fuel cycle. These data update and extend previously recommended handbook values. We derive transfer coefficients to terrestrial foods and describe the systematics of the derived transfer coefficients. Suggestions are offered for changes in the values of transfer coefficients to terrestrial foods that now appear in federal regulatory guides. Deficiencies in our present knowledge concerning transfer coefficients and limitations in the use of these values to ensure compliance with radiation protection standards are discussed. (orig.) 891 HP/orig. 892 MB
Drag Coefficient of Hexadecane Particles
Nakao, Yoshinobu; Hishida, Makoto; Kajimoto, Sadaaki; Tanaka, Gaku
This paper deals with the drag coefficient of solidified hexadecane particles and their free rising velocity in liquid. The drag coefficient was experimentally investigated in Reynolds number range of about 40-300. The present experimental results are summarized in the following; (1) the drag coefficient of solidified hexadecane particles formed in liquid coolant by direct contact cooling is higher than that of a smooth surface sphere, this high drag coefficient seems to be attributed to the non-smooth surface of the solidified hexadecane particles, (2) experimental correlation for the drag coefficient of the solidified hexadecane particles was proposed, (3 ) the measured rising velocity of the solidified hexadecane particle agrees well with the calculated one, (4) the drag coefficients of hexadecane particles that were made by pouring hexadecane liquid into a solid hollow sphere agreed well with the drag coefficient of smooth surface sphere.
Sabine absorption coefficients to random incidence absorption coefficients
DEFF Research Database (Denmark)
Jeong, Cheol-Ho
2014-01-01
Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients into...... random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...
Quadrature formulas for Fourier coefficients
Bojanov, Borislav; Petrova, Guergana
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.
Quadrature formulas for Fourier coefficients
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.
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 h...
Standardized Discriminant Coefficients: A Rejoinder.
Mueller, Ralph O.; Cozad, James B.
1993-01-01
Although comments of D.J. Nordlund and R. Nagel are welcomed, their arguments are not sufficient to accept the recommendation of using total variance estimates to standardize canonical discriminant function coefficients. If standardized coefficients are used to help interpret a discriminant analysis, pooled within-group variance estimates should…
Computational Seebeck Coefficient Measurement Simulations
Martin, Joshua
2012-01-01
We have employed finite element analysis to develop computational Seebeck coefficient metrology simulations. This approach enables a unique exploration of multiple probe arrangements and measurement techniques within the same temporal domain. To demonstrate the usefulness of this approach, we have performed these Seebeck coefficient measurement simulations to quantitatively explore perturbations to voltage and temperature correspondence, by comparing simultaneous and staggered data acquisitio...
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.
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.
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)).
Uq(sl(2)) invariant operators and minimal theories fusion matrices
International Nuclear Information System (INIS)
The existence of Uq(sl(2)) invariant operators for qp=1 leads to relations for the quantum Clebsch-Gordan kernels and for the quantum 6j-symbols (= fusion matrices). These relations effectively reduce some equalities, inherited from the generic q case, and imply, in particular, that the polynomial identities for the quantum 6j-symbols are consistent with the minimal theories chiral fusion rules. (author). 26 refs
8D oscillator as a hidden SU(2) monopole
International Nuclear Information System (INIS)
With help of the generalized version of the Hurwitz transformation, the five-dimensional SU(2)-monopole model is constructed analytically from the eight-dimensional quantum oscillator. The Clebsch-Gordan expansion stimulated by the space-gauge coupling, the hyperangular and the radial parts of the total wave function, the energy spectrum of the charge-monopole bound system, and the corresponding degeneracy are calculated
Predicting Abraham model solvent coefficients
Bradley, Jean-Claude; Abraham, Michael H; Acree, William E; Lang, Andrew SID
2015-01-01
Background The Abraham general solvation model can be used in a broad set of scenarios involving partitioning and solubility, yet is limited to a set of solvents with measured Abraham coefficients. Here we extend the range of applicability of Abraham’s model by creating open models that can be used to predict the solvent coefficients for all organic solvents. Results We created open random forest models for the solvent coefficients e, s, a, b, and v that had out-of-bag R2 values of 0.31, 0.77...
Reactivity coefficients by perturbation theory
International Nuclear Information System (INIS)
The development of the formulae of perturbation theory provides a good opportunity to use one of the principal devices of mathematical heuristics, i.e. proceeding by analogy from something that is simple to something that is more complicated. This paper: (a) Reviews the formulation of perturbation theory as a method of calculating reactivity coefficients; this consists mainly of developing the differential equation for the adjoint flux, as a continuous function of position and lethargy, by proceeding by analogy from the one-group differential equation for adjoint flux. (b) Presents an application of the two-group form of perturbation theory to a boiling-mercury-cooled fast-breeder reactor (MCBR). It is seen that the net Hg density coefficient of reactivity for the first-design-try for the MCBR is negative for some regions and positive for others. However, it is negative for regions of highest statistical weight and where the density change for a power change would be the greatest. The overall Hg density coefficient is thus negative, i.e. the void coefficient is positive-an unsafe condition. It can be easily seen from the two-group formulation what design changes had to be made to obtain a design which would have a negative void coefficient. It developed in subsequent investigations that there were such design changes that could be made and a design of the MCBR with a negative void coefficient was eventually achieved. (author)
Transport coefficients of heavy baryons
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.
Analysis of internal conversion coefficients
International Nuclear Information System (INIS)
An extensive database has been assembled that contains the three most widely used sets of calculated internal conversion coefficients (ICC): [Hager R.S., Seltzer E.C., 1968. Internal conversion tables. K-, L-, M-shell Conversion coefficients for Z=30 to Z=103, Nucl. Data Tables A4, 1-237; Band I.M., Trzhaskovskaya M.B., 1978. Tables of gamma-ray internal conversion coefficients for the K-, L- and M-shells, 10≤Z≤104, Special Report of Leningrad Nuclear Physics Institute; Roesel F., Fries H.M., Alder K., Pauli H.C., 1978. Internal conversion coefficients for all atomic shells, At. Data Nucl. Data Tables 21, 91-289] and also includes new Dirac-Fock calculations [Band I.M. and Trzhaskovskaya M.B., 1993. Internal conversion coefficients for low-energy nuclear transitions, At. Data Nucl. Data Tables 55, 43-61]. This database is linked to a computer program to plot ICCs and their combinations (sums and ratios) as a function of Z and energy, as well as relative deviations of ICC or their combinations for any pair of tabulated data. Examples of these analyses are presented for the K-shell and total ICCs of the gamma-ray standards [Hansen H.H., 1985. Evaluation of K-shell and total internal conversion coefficients for some selected nuclear transitions, Eur. Appl. Res. Rept. Nucl. Sci. Tech. 11.6 (4) 777-816] and for the K-shell and total ICCs of high multipolarity transitions (total, K-, L-, M-shells of E3 and M3 and K-shell of M4). Experimental data sets are also compared with the theoretical values of these specific calculations
Viscosity coefficient with pairing interaction
International Nuclear Information System (INIS)
In the study of dynamic process (for example, deep-inelastic scattering of heavy ion, nuclear fission), viscosity, which describes the coupling between the intrinsic degrees of freedom and the collective one, is a basic quantity. In this paper, under BCS approximation, we derive a microscopic expression of viscosity coefficient with pairing interaction by means of a linear response theory. Taking the fission process of 236U as an example, we discuss the effect of pairing interaction on the viscosity coefficient. The results show that pairing interaction must be taken into account at lower temperature and can be neglected at a high-temperature region
Estimating the Polyserial Correlation Coefficient.
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)
Fresnel coefficients as hyperbolic rotations
Monzon, J. J.; Sanchez-Soto, L. L.
2001-01-01
We describe the action of a plane interface between two semi-infinite media in terms of a transfer matrix. We find a remarkably simple factorization of this matrix, which enables us to express the Fresnel coefficients as a hyperbolic rotation.
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...
Clustering Coefficients in Multiplex Networks
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.
Portable vapor diffusion coefficient meter
Ho, Clifford K.
2007-06-12
An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.
SPATIAL DEPENDENCE OF REACTIVITY COEFFICIENTS
Salah, Sideeg
2011-01-01
The objective of this thesis is to study and understand the behavior of the reactivity coefficients (RCs) in a boiling water reactor (BWR) partially within 25 different segments with different void fractions, with enriched oxide fuel (UOX) core, as well as to evaluate the methodologies exposed in [10]. These two normalization methods (described in chapter 3) are used to analyse the contribution of each segment of the core having different regions (fuel, clad, coolant, moderator and channel b...
Matrix Fourier transform with discontinuous coefficients
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...
Investigating bias in squared regression structure coefficients
Nimon, Kim F.; Zientek, Linda R.; Thompson, Bruce
2015-01-01
The importance of structure coefficients and analogs of regression weights for analysis within the general linear model (GLM) has been well-documented. The purpose of this study was to investigate bias in squared structure coefficients in the context of multiple regression and to determine if a formula that had been shown to correct for bias in squared Pearson correlation coefficients and coefficients of determination could be used to correct for bias in squared regression structure coefficie...
Diffusion coefficients for absorbing materials
International Nuclear Information System (INIS)
A method to improve the diffusion results for systems containing strong absorbers is described. Each absorbing material is transformed into an equivalent rectangle. Transport and diffusion calculations in slab geometry are performed for both directions of the rectangle, and group-dependent diffusion coefficients are determined by matching the outgoing currents. Test problems comprise a critical slab, a compact PWR fuel element storage pool and two BWR fuel elements with a control rod and a poison cell. The multiplication factors of these systems are calculated with an accuracy of 1 to 2%. (Auth.)
Higher Order Macro Coefficients in Periodic Homogenization
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.
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.
VHTRC temperature coefficient benchmark problem
International Nuclear Information System (INIS)
As an activity of IAEA Coordinated Research Programme, a benchmark problem is proposed for verifications of neutronic calculation codes for a low enriched uranium fuel high temperature gas-cooled reactor. Two problems are given on the base of heating experiments at the VHTRC which is a pin-in-block type core critical assembly loaded mainly with 4% enriched uranium coated particle fuel. One problem, VH1-HP, asks to calculate temperature coefficient of reactivity from the subcritical reactivity values at five temperature steps between an room temperature where the assembly is nearly at critical state and 200degC. The other problem, VH1-HC, asks to calculate the effective multiplication factor of nearly critical loading cores at the room temperature and 200degC. Both problems further ask to calculate cell parameters such as migration area and spectral indices. Experimental results corresponding to main calculation items are also listed for comparison. (author)
Index-free Heat Kernel Coefficients
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...
Innovative Correlation Coefficient Measurement with Fuzzy Data
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.
Diffusion coefficient in photon diffusion theory
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
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.
Standards for Standardized Logistic Regression Coefficients
Menard, Scott
2011-01-01
Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…
Soccer Ball Lift Coefficients via Trajectory Analysis
Goff, John Eric; Carre, Matt J.
2010-01-01
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…
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.
Energy coefficients for a propeller series
DEFF Research Database (Denmark)
Olsen, Anders Smærup
2004-01-01
The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use 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....
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
Rotational raman lidar for aerosol scattering coefficients
International Nuclear Information System (INIS)
Two channel lidar signals which are composed of the total rotational scattering and elastic signals provide good information for the aerosol scattering coefficients. We can calculate the aerosol backscattering coefficient and extinction coefficient directly without any assumption and calibration process. Generally, a high spectral resolution lidar is used for an aerosol monitoring. But we have designed a new normal spectral receiving lidar system which contains the scattering information simultaneously, and we have retrieved the aerosol scattering coefficient. The results show that there is no need to assume any relation between the aerosol backscattering and extinction and to consider any wavelength calibration process for the aerosol scattering coefficient
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
Enlarged symmetry algebras of spin chains, loop models, and S-matrices
International Nuclear Information System (INIS)
The symmetry algebras of certain families of quantum spin chains are considered in detail. The simplest examples possess m states per site (m>=2), with nearest-neighbor interactions with U(m) symmetry, under which the sites transform alternately along the chain in the fundamental m and its conjugate representation m-bar. We find that these spin chains, even with arbitrary coefficients of these interactions, have a symmetry algebra Am much larger than U(m), which implies that the energy eigenstates fall into sectors that for open chains (i.e., free boundary conditions) can be labeled by j=0,1,...,L, for the 2L-site chain such that the degeneracies of all eigenvalues in the jth sector are generically the same and increase rapidly with j. For large j, these degeneracies are much larger than those that would be expected from the U(m) symmetry alone. The enlarged symmetry algebra Am(2L) consists of operators that commute in this space of states with the Temperley-Lieb algebra that is generated by the set of nearest-neighbor interaction terms; Am(2L) is not a Yangian. There are similar results for supersymmetric chains with gl(m+n|n) symmetry of nearest-neighbor interactions, and a richer representation structure for closed chains (i.e., periodic boundary conditions). The symmetries also apply to the loop models that can be obtained from the spin chains in a spacetime or transfer matrix picture. In the loop language, the symmetries arise because the loops cannot cross. We further define tensor products of representations (for the open chains) by joining chains end to end. The fusion rules for decomposing the tensor product of representations labeled j1 and j2 take the same form as the Clebsch-Gordan series for SU(2). This and other structures turn the symmetry algebra Am into a ribbon Hopf algebra, and we show that this is 'Morita equivalent' to the quantum group Uq(sl2) for m=q+q-1. The open-chain results are extended to the cases vertical bar m vertical barm or Uq(sl2
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
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.
Quantum algebra Uqp(u2) and application to the rotational collective dynamics of the nuclei
International Nuclear Information System (INIS)
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 Uqp(u2). More precisely, we develop its Hopf algebraic structure and we study its co-product structure. The bases of the representation theory of Uqp(u2) are introduced. On one hand, we construct the finite-dimensional irreducible representations of Uqp(u2). 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 Uqp(u2), Uq2(su2) and Uqp(u1,1). 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 Uqp(u2). 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 Uqp(u2) leads to a generalization of the Uq(su2)-rotator model. We also introduce a new model of the anharmonic oscillator on the basis of the quantum algebra Uqp(u2). We show that the system of the Uq(su2)-rotator and of the anharmonic oscillator can be coupled with the use of the deformation parameters of Uqp(u2). A ro-vibration energy formula and expansion 'a la' Dunham are obtained. The aim of the lest part is to apply our non rigid rotator model to the rotational collective dynamics of the superdeformed nuclei of the A∼130 - 150 and A∼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 arising from four other models of the non rigid rotator. A comparative analysis is given in terms of transition energies. We calculate the dynamical moments of inertia with the fitted parameters. A comparison between the results of different models shows the role played by
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)
Determination of the surface drag coefficient
DEFF Research Database (Denmark)
Mahrt, L.; Vickers, D.; Sun, J.L.;
2001-01-01
This study examines the dependence of the surface drag coefficient on stability, wind speed, mesoscale modulation of the turbulent flux and method of calculation of the drag coefficient. Data sets over grassland, sparse grass, heather and two forest sites are analyzed. For significantly unstable ...... of calculation, partly due to meandering of the stress vector.......This study examines the dependence of the surface drag coefficient on stability, wind speed, mesoscale modulation of the turbulent flux and method of calculation of the drag coefficient. Data sets over grassland, sparse grass, heather and two forest sites are analyzed. For significantly unstable...... conditions, the drag coefficient does not depend systematically on z/L but decreases with wind speed for fixed intervals of z/L, where L is the Obukhov length. Even though the drag coefficient for weak wind conditions is sensitive to the exact method of calculation and choice of averaging time, the decrease...
Remarks on the maximum correlation coefficient
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.
The Intuitionistic Fuzzy Normed Space of Coefficients
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.
NEW CORRELATION COEFFICIENT FOR DATA ANALYSIS
Falie, Dragos; Livia DAVID
2012-01-01
The proposed correlation coefficient better characterize the statistical independence of two random variables that are a linear mixture of two independent sources. This correlation coefficient can be calculated with analytical relations or with the known algorithms of independent components analysis (ICA). The value of the correlation coefficient is zero when the random variables are a statistically independent and it is one when these are fully dependent.
Index-free Heat Kernel Coefficients
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...
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.
Alternatives to Pearson's and Spearman's Correlation Coefficients
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.
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...
A gain-coefficient switched Alexandrite laser
Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.
2012-01-01
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 at a repetition rate of 5 Hz.
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.
International Nuclear Information System (INIS)
Rare earth compounds have potential applications in thermoelectric devices due to their large value conductivity and Seebeck coefficient. CePd3 has the highest reported Seebeck coefficient (S ∼ 125 μV/K), when doped appropriately, among all rare-earth compounds. This high value is explained as a result of the placement of the cerium f1 level. (author)
Coefficient Alpha Bootstrap Confidence Interval under Nonnormality
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…
On Burnett coefficients in periodic media
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.
A gain-coefficient switched Alexandrite laser
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
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...
Effective stress coefficient for uniaxial strain condition
DEFF Research Database (Denmark)
Alam, Mohammad Monzurul; Fabricius, Ida Lykke
2012-01-01
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 determined under uniaxial strain condition will be more relevant in reservoir studies....
Coefficients of heat transfer in condensation
International Nuclear Information System (INIS)
The authors analyze the problem of determining the coefficients of heat transfer in the condensation of steam on vertical walls in terms of the Prandtl hypothesis and the Reynolds analogy for distribution of the turbulent thermal conductivity across the condensate film. From the assumed model the authors derived expressions for the heat transfer coefficients
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.
Effective stress coefficient for uniaxial strain condition
DEFF Research Database (Denmark)
Alam, M.M.; Fabricius, I.L.
2012-01-01
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 determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....
Effective stress coefficient for uniaxial strain condition
DEFF Research Database (Denmark)
Alam, Mohammad Monzurul; Fabricius, Ida Lykke
2012-01-01
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...
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.
Friction Coefficient for Quarks in Supergravity Duals
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.
On diffusion approximation with discontinuous coefficients
Krylov, N. V.; Liptser, R.
2002-01-01
Convergence of stochastic processes with jumps to diffusion processes is investigated in the case when the limit process has discontinuous coefficients. An example is given in which the diffusion approximation of a queueing model yields a diffusion process with discontinuous diffusion and drift coefficients.
Tracking time-varying coefficient-functions
DEFF Research Database (Denmark)
Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.;
2000-01-01
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 is a...
Estimating Runoff Coefficients Using Weather Radars
DEFF Research Database (Denmark)
Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.;
2012-01-01
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...
Gini coefficient as a life table function
Directory of Open Access Journals (Sweden)
2003-06-01
Full Text Available This paper presents a toolkit for measuring and analyzing inter-individual inequality in length of life by Gini coefficient. Gini coefficient and four other inequality measures are defined on the length-of-life distribution. Properties of these measures and their empirical testing on mortality data suggest a possibility for different judgements about the direction of changes in the degree of inequality by using different measures. A new computational procedure for the estimation of Gini coefficient from life tables is developed and tested on about four hundred real life tables. The estimates of Gini coefficient are precise enough even for abridged life tables with the final age group of 85+. New formulae have been developed for the decomposition of differences between Gini coefficients by age and cause of death. A new method for decomposition of age-components into effects of mortality and composition of population by group is developed. Temporal changes in the effects of elimination of causes of death on Gini coefficient are analyzed. Numerous empirical examples show: Lorenz curves for Sweden, Russia and Bangladesh in 1995, proportional changes in Gini coefficient and four other measures of inequality for the USA in 1950-1995 and for Russia in 1959-2000. Further shown are errors of estimates of Gini coefficient when computed from various types of mortality data of France, Japan, Sweden and the USA in 1900-95, decompositions of the USA-UK difference in life expectancies and Gini coefficients by age and cause of death in 1997. As well, effects of elimination of major causes of death in the UK in 1951-96 on Gini coefficient, age-specific effects of mortality and educational composition of the Russian population on changes in life expectancy and Gini coefficient between 1979 and 1989. Illustrated as well are variations in life expectancy and Gini coefficient across 32 countries in 1996-1999 and associated changes in life expectancy and Gini
Diffusion coefficients of paracetamol in aqueous solutions
International Nuclear Information System (INIS)
Highlights: ► Mutual diffusion coefficients of paracetamol in aqueous dilute solutions. ► Influence of the thermodynamic factors on the variation of their mutual diffusion coefficients. ► Estimation of the mutual limiting diffusion coefficients of the molecular, Dm0, and ionized forms, D±0, of this drug. - Abstract: Binary mutual diffusion coefficients measured by the Taylor dispersion method, for aqueous solutions of paracetamol (PA) at concentrations from (0.001 to 0.050) mol·dm−3 at T = 298.15 K, are reported. From the Nernst–Hartley equation and our experimental results, the limiting diffusion coefficient of this drug and its thermodynamic factors are estimated, thereby contributing in this way to a better understanding of the structure of such systems and of their thermodynamic behaviour in aqueous solution at different concentrations.
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)
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)
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.
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.
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
Generalized Coefficients for Hopf Cyclic Cohomology
Hassanzadeh, Mohammad; Kucerovsky, Dan; Rangipour, Bahram
2014-09-01
A category of coefficients for Hopf cyclic cohomology is defined. It is shown that this category has two proper subcategories of which the smallest one is the known category of stable anti Yetter-Drinfeld modules. The middle subcategory is comprised of those coefficients which satisfy a generalized SAYD condition depending on both the Hopf algebra and the (co)algebra in question. Some examples are introduced to show that these three categories are different. It is shown that all components of Hopf cyclic cohomology work well with the new coefficients we have defined.
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.
Combinatorics of 3n-j coefficients
International Nuclear Information System (INIS)
The purpose of this paper is to outline the general theory of recouping coefficients in the theory of angular momentum form the viewpoint of generating functions along the lines initiated by Schwinger, but with special emphasis on the combinatorial aspects
Transonic Blunt Body Aerodynamic Coefficients Computation
Sancho, Jorge; Vargas, M.; Gonzalez, Ezequiel; Rodriguez, Manuel
2011-05-01
In the framework of EXPERT (European Experimental Re-entry Test-bed) accurate transonic aerodynamic coefficients are of paramount importance for the correct trajectory assessment and parachute deployment. A combined CFD (Computational Fluid Dynamics) modelling and experimental campaign strategy was selected to obtain accurate coefficients. A preliminary set of coefficients were obtained by CFD Euler inviscid computation. Then experimental campaign was performed at DNW facilities at NLR. A profound review of the CFD modelling was done lighten up by WTT results, aimed to obtain reliable values of the coefficients in the future (specially the pitching moment). Study includes different turbulence modelling and mesh sensitivity analysis. Comparison with the WTT results is explored, and lessons learnt are collected.
Thermal Expansion Coefficients of Thin Crystal Films
Institute of Scientific and Technical Information of China (English)
无
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.
Photon diffusion coefficient in an absorbing medium
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...
Experimental determination of bagasse stiffness coefficient
Nelson Arzola de la Peña
2010-01-01
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...
A Kendall correlation coefficient for functional dependence
Valencia García, Dalia Jazmín; Romo, Juan; Lillo, Rosa E.
2013-01-01
Measuring dependence is a basic question when dealing with functional observations. The usual correlation for curves is not robust. Kendall's coefficient is a natural description of dependence between finite dimensional random variables. We extend this concept to functional observations. Given a bivariate sample of functions, a robust analysis of dependence can be carried out through the functional version of a Kendall correlation coefficient introduced in this paper. We also study its statis...
Clustering coefficient without degree correlations biases
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...
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.
Onsager coefficients of a Brownian Carnot cycle
Izumida, Yuki; Okuda, Koji
2010-01-01
We study a Brownian Carnot cycle introduced by T. Schmiedl and U. Seifert [Europhys. Lett. \\textbf{81}, 20003 (2008)] from a viewpoint of the linear irreversible thermodynamics. By considering the entropy production rate of this cycle, we can determine thermodynamic forces and fluxes of the cycle and calculate the Onsager coefficients for general protocols, that is, arbitrary schedules to change the potential confining the Brownian particle. We show that these Onsager coefficients contain the...
Diffusion Coefficients of Fluorinated Surfactants in Water:
Pereira, Luís A.M.; Martins, Luís F. G.; Ascenso, José R.; Morgado, Pedro; Ramalho, João P. P.; Filipe, Eduardo J. M.
2014-01-01
Intradiffusion coefficients of 2,2,2-trifluoroethanol in water have been measured by the pulsed field gradient (PFG)-NMR spin−echo technique as a function of temperature and composition on the dilute alcohol region. The measurements extend the range of compositions already studied in the literature and, for the first time, include the study of the temperature dependence. At the same time, intradiffusion coefficients of 2,2,2-trifluoroethanol, 2,2,3,3,3-pentafluoropropan-1-ol, ...
Investigation of photon attenuation coefficients for marble
International Nuclear Information System (INIS)
The total linear attenuation coefficients μ (cm-1) have been obtained using the XCOM program at photon energies of 1 keV to 1 GeV for six different natural marbles produced in different places in Turkey. The individual contribution of photon interaction processes to the total linear attenuation coefficients for marble has been investigated. The calculated results were also compared with the measurements. The results obtained for marble were also compared with concrete. (note)
Fractal fractal dimensions of deterministic transport coefficients
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...
Decomposition of the Gini coefficient using Stata
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...
Transport coefficients for inelastic Maxwell mixtures
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...
Multiple poes and other features of affine Toda field theory
International Nuclear Information System (INIS)
Some perturbative features of affine Toda field theory are explored, in particular the mechanisms responsible for the first-, second- and third-order poles in the conjectured exact factorisable S-matrices in the ADE series of models. It is found that generic collections of Feynman diagrams are responsible for the leading order poles in any of the theories. However, the complexity is such that it has not yet proved possible to analyse all the singularities that occur up to order twelve. Some comments are made on an associated tiling problem and on an interesting connection between the affine Toda couplings and the Clebsch-Gordan decomposition of tensor products. (orig.)
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)
Experimental Mg IX photorecombination rate coefficient
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.
Inverse determination of local heat transfer coefficient
International Nuclear Information System (INIS)
The naphtalene sublimation and transient methods are widely used techniques which are particularly useful in complex flows and solid shapes. Both techniques have been widely used with considerable success but they are not appropriate for high temperatures. An alternative method to obtain the local convective heat transfer coefficient, that does not have any disadvantages noted above, is the inverse procedure. Determination of the space-variable heat transfer coefficient on a complex shape surface requires the solution of the nonlinear inverse heat conduction problem. The distribution of the heat transfer coefficient is calculated from temperature measurements at interior points of the solid and measured fluid temperature. The unknown parameters associated with the solution are selected to achieve the closest agreement in a least squares sense between the computed and measured temperatures using the Levenberg - Marquardt method. The nonlinear least - squares problem is parameterized by assuming the staircase changes of heat transfer coefficient on the boundary or expressing the space variations of the heat transfer coefficient in the functional form. The uncertainties in the estimated components of the heat transfer coefficient or in the estimated parameters are determined for the temperature measurements with known and unknown standard deviations. The determination of the circumferential heat transfer coefficient distribution on the heated tube with two longitudinal fins in cross flow demonstrates the accuracy of the developed method. The actual experimental data were used. Experiments were performed with an array of vertical tubes arranged in staggered pattern. The experimental results reported herein are among the first that show the variation of the local heat transfer coefficients over the circumference of the finned tube. Most data reported previously were acquired for smooth tubes at low temperatures. The main advantage of the method is that it does not
Experimental Mg IX photorecombination rate coefficient
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...
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.
Ekström, Joakim
2011-01-01
Spearman’s rank correlation coefficient is shown to be a deterministic transformation of the empirical polychoric correlation coefficient. The transformation is a homeomorphism under given marginal probabilities, and has a fixed point at zero. Moreover, the two measures of association for ordinal variables are asymptotically equivalent, in a certain sense. If the ordinal variables arise from discretizations, such as groupings of values into categories, Spearman’s rank correlation coefficient ...
Improved Diffusion Coefficients for Stellar Plasmas
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.
Curvature of Indoor Sensor Network: Clustering Coefficient
Directory of Open Access Journals (Sweden)
2009-03-01
Full Text Available We investigate the geometric properties of the communication graph in realistic low-power wireless networks. In particular, we explore the concept of the curvature of a wireless network via the clustering coefficient. Clustering coefficient analysis is a computationally simplified, semilocal approach, which nevertheless captures such a large-scale feature as congestion in the underlying network. The clustering coefficient concept is applied to three cases of indoor sensor networks, under varying thresholds on the link packet reception rate (PRR. A transition from positive curvature (“meshed” network to negative curvature (“core concentric” network is observed by increasing the threshold. Even though this paper deals with network curvature per se, we nevertheless expand on the underlying congestion motivation, propose several new concepts (network inertia and centroid, and finally we argue that greedy routing on a virtual positively curved network achieves load balancing on the physical network.
A drying coefficient for building materials
DEFF Research Database (Denmark)
Scheffler, Gregor Albrecht; Plagge, Rudolf
2009-01-01
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, in...... many cases such a coefficient would be highly appreciated, e.g. in interaction of industry and research or for the distinction and selection of suitable building materials throughout design and practise. This article first highlights the importance of drying experiments for hygrothermal...... 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...
Understanding correlation coefficients in treaty verification
Energy Technology Data Exchange (ETDEWEB)
DeVolpi, A.
1991-11-01
When a pair of images are compared on a point-by-point basis, the linear-correlation coefficient is usually used as a measure of similarity or dissimilarity. This paper evaluates the theoretical underpinnings and limitation of the linear-correlation coefficient, as well as other related statistics, particularly for cases where inherent white noise is present. As a result of the limitations in linear-correlation, an additional step has been derived -- local-sum clustering -- in order to improve recognition of small dissimilarities in a pair images. Results show that three-stage procedure, consisting of first establishing congruence of the two images, than using the linear-correlation coefficient as a test of true negatives, and finally qualifying a true positive by using the cluster (local-sum) method. These algorithmic stages would be especially useful in arms control treaty verification.
The axial distribution of reactivity coefficients
International Nuclear Information System (INIS)
The purpose of the present work is to investigate the correlation of the axial distributions of the different reactivity coefficients with the neutron flux and the neutron flux squared. Calculations were carried out for the Zion Unit 2 PWR. Reactivity coefficients, forward fluxes and adjoint fluxes were all computed and correlations obtained. The core length was divided into 7 axial regions in order to obtain the effect on reactivity in the reactor as a whole of changing the cross sections in each axial region in turn. The parameters chosen for change were coolant density, coolant temperature and fuel temperature. The results appear to bear out our original hypothesis that the reactivity coefficient profiles have a higher positive correlation with the total flux squared profile than with the linear flux profile. (authors). 5 refs., 2 figs
Oxygen atom loss coefficient of carbon nanowalls
Energy Technology Data Exchange (ETDEWEB)
Mozetic, Miran, E-mail: miran.mozetic@guest.arnes.si [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Vesel, Alenka [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Stoica, Silviu Daniel; Vizireanu, Sorin; Dinescu, Gheorghe [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilo Street, PO Box MG-36, Magurele, Bucharest 077125 (Romania); Zaplotnik, Rok [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia)
2015-04-01
Highlights: • Atomic oxygen loss coefficient on carbon nanowalls (CNWs) was evaluated. • Atomic oxygen loss coefficient of CNW is the largest among any known materials. • Surface atom loss is a major loss mechanism at room temperatures. - Abstract: Extremely high values of atomic oxygen loss coefficient on carbon nanowall (CNW) surface are reported. CNW layers consisting of interconnected individual nanostructures with average length of 1.1 μm, average thickness of 66 nm and surface density of 3 CNW/μm{sup 2} were prepared by plasma jet enhanced chemical-vapor deposition using C{sub 2}H{sub 2}/H{sub 2}/Ar gas mixtures. The samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectrometry (RS) as well as X-ray photoelectron spectroscopy (XPS). The surface loss coefficient was measured at room temperature in a flowing afterglow at different densities of oxygen atoms supplied from inductively coupled radiofrequency O{sub 2} plasma. The RF generator operated at 13.56 MHz and different nominal powers up to 900 W corresponding to different O-atom density in the afterglow up to 1.3 × 10{sup 21} m{sup −3}. CNW and several different samples of known coefficients for heterogeneous surface recombination of neutral oxygen atoms have been placed separately in the afterglow chamber and the O-atom density in their vicinity was measured with calibrated catalytic probes. Comparison of measured results allowed for determination of the loss coefficient for CNWs and the obtained value of 0.59 ± 0.03 makes this material an extremely effective sink for O-atoms.
Super-b4 coefficients in supergravity
International Nuclear Information System (INIS)
For covariantly chiral superfields coupled to background Yang-Mills superfields and defined on a curved superspace background, the superfield analogue of the heat kernel associated with the differential operator appearing in the quadratic part of the action is defined. The super-b4 coefficient in the asymptotic expansion of the kernel is computed using a system of superspace normal coordinates. These coefficients are shown to determine the one-loop trace supermultiplet and the one-loop logarithmic divergence for pure supergravity. (author)
Criterions for fixing regulatory seismic acceleration coefficients
International Nuclear Information System (INIS)
Acceleration coeffficients to be taken into account in seismic areas for calculation of structures are defined in national seismic regulations. Joined to the described qualitative requirements, these coefficients represent a balance between precaution costs and avoided damages, both in terms of material repairing costs and damage to human life. Persons in charge of fixing these coefficients must be informed of corresponding quantitative aspects. Data on seismic motions occurrencies and consequences are gathered here and convoluted to mean damage evaluations. Indications on precaution costs are joined, which shows that currently recommended levels of seismic motions are high relatively to financial profitability, and represent in fact an aethical choice about human life value
Bayes estimation of the multiple correlation coefficient
Tiwari, RC
1989-01-01
Let R denote the population multiple correlation coefficient of one variable on the other (m-1), in a m-variate normal —2 distribution. Bayes estimator of R, given only the sample 2 multiple correlation coefficient R, is derived with respect to the squared error loss function and a Beta prior distribution.-2 These results are then related to the Bayes estimates of R /(1-_o R), a parameter considered recently by Muirhead (1985). The ideas are illustrated and the effect of various parameters st...
ANL results for LMFR reactivity coefficients benchmark
International Nuclear Information System (INIS)
The fast reactor analysis methods developed at ANL were extensively tested in ZPR and ZPPR experiments, applied to EBR-2 and FFTF test reactors. The basic nuclear data library used was ENDF/B-V.2 with the ETOE-2 data processing code and the ENDF/B-VI. Multigroup constants were generated by Monte Carlo code MCNP2-2. Neutron flux calculation were done by DIF3D code applying neutron diffusion theory and finite difference method. The results obtained include basic parameters; fuel and structure regional Doppler coefficients; geometry expansion fuel coefficients; kinetics parameters. In general, agreement between phase 1 and 2 results were excellent
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 .
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
Study on the Friction Coefficient in Grinding
Institute of Scientific and Technical Information of China (English)
无
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...
Coefficient of Restitution of Wet Tennis Balls
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...
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...
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.
Pressure-viscosity coefficient of biobased lubricants
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...
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.
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.
Combinatorics of 3n-j coefficients
International Nuclear Information System (INIS)
The binary coupling theory of the addition of n+1 angular momenta, or, equivalently, of the reduction of n+1 multiple Kronecker products of the unitary irreducible representations of the unitary group SU(2), is reviewed with emphasis on the combinatorial structure. Using labeled binary trees, we give the generating function for the coupled angular-momentum function corresponding to every binary coupling scheme. From this result, we obtain the generating function for the coefficients for all recoupling coefficients. We generalize the methods of Schwinger, but formulated in the ring of polynomials. A key concept for recoupling coefficients is the double Pfaffian, which is closely related to MacMahon's master theorem. Work in progress includes the classification of 3n-j coefficients, the investigation of representations of U(n+1) that arise from its right action on the 2x(n+1) matrix Z of indeterminates whose columns are the two-component spinors associated with the (n+1)-angular-momentum basis function, and related problems
Calculation of aberration coefficients by ray tracing
Czech Academy of Sciences Publication Activity Database
Oral, Martin; Lencová, Bohumila
2009-01-01
Roč. 109, č. 11 (2009), s. 1365-1373. ISSN 0304-3991 R&D Projects: GA AV ČR IAA100650805 Institutional research plan: CEZ:AV0Z20650511 Keywords : Aberrations * Aberration coefficients * Ray tracing * Regression * Fitting Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.067, year: 2009
The Evolution of Pearson's Correlation Coefficient
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…
Confidence Intervals for Cronbach's Coefficient Alpha Values
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
Pressure viscosity coefficient of vegetable oils
The elastohydrodynamic (EHD) pressure viscosity coefficient (PVC) of ten vegetable oils from commodity and new crops, and two petroleum-based oils, polyalphaolefin (PAO) and hexadecane, were investigated. PVC was measured using three different methods: the So and Klaus (S-K) procedure from oil visco...
Coefficient Quantization for Frames in Banach Spaces
Casazza, P. G.; Dilworth, S. J.; Odell, E.; Schlumprecht, Th.; Zsak, Andras
2007-01-01
Let $(e_i)$ be a fundamental system of a Banach space. We consider the problem of approximating linear combinations of elements of this system by linear combinations using quantized coefficients. We will concentrate on systems which are possibly redundant. Our model for this situation will be frames in Banach spaces.
Diffusion Coefficient Measurements: Sulphuric Acid – Air
Czech Academy of Sciences Publication Activity Database
Brus, David; Neitola, K.; Petäjä, T.; Lihavainen, H.
Helsinki : -, 2010, P2L7. ISBN N. [International Aerosol Conference IAC 2010. Helsinki (FI), 29.08.2010-03.09.2010] Institutional research plan: CEZ:AV0Z40720504 Keywords : diffusion coefficient * sulphuric acid * flow tube Subject RIV: CF - Physical ; Theoretical Chemistry www.iac2010.fi
Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions
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.…
Uses and Misuses of the Correlation Coefficient.
Onwuegbuzie, Anthony J.; Daniel, Larry G.
The purpose of this paper is to provide an in-depth critical analysis of the use and misuse of correlation coefficients. Various analytical and interpretational misconceptions are reviewed, beginning with the egregious assumption that correlational statistics may be useful in inferring causality. Additional misconceptions, stemming from…
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.
Molar extinction coefficients of some fatty acids
DEFF Research Database (Denmark)
Sandhu, G.K.; Singh, K.; Lark, B.S.; Gerward, Leif
2002-01-01
) and stearic acid (C18H36O2), 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...
Power coefficient anomaly in Joyo, (2)
International Nuclear Information System (INIS)
In this report, the presumption about the mechanism having caused the power coefficient anomaly in Joyo during the 75 MW power-raising test in 1979 is described. After the previous report, the new information about the results of the post-irradiation examination and the analysis of the power coefficient of Joyo were able to be obtained. From these information, the mechanism of causing the anomaly was presumed as follows. In 50 MW operation, the fuel burnup reached about 10,000 MWD/ton at the end of second cycle, and produced fission gas was almost retained in fuel pellets. When the power was raised from 50 MW to 75 MW for the first time, the fission gas began to be released when 50 MW was somewhat exceeded. The fission gas release caused the temperature rise and cracking of fuel pellets, and elongated fuel stack length abruptly. These phenomena induced to enlarge the fuel expansion reactivity effect and Doppler reactivity effect, and caused the anomalous behavior of power coefficient. After reaching 75 MW, the fuel stack length did not respond normally to reactor power change, and the magnitude of power coefficient became smaller. The reactivity was lost considerably from the core after the anomaly. (Kako, I.)
Second virial coefficients of dipolar hard spheres
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
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...
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.
Coefficient of Restitution of a Tennis Ball
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.
Bitplane Image Coding With Parallel Coefficient Processing.
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. PMID:26441420
Tracking Time-Varying Coefficient-Functions
DEFF Research Database (Denmark)
Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.; Madsen, Henrik; Holst, Jan
1999-01-01
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 of recur...
Measuring correlations between non-stationary series with DCCA coefficient
Kristoufek, Ladislav
2014-05-01
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 correlation coefficient. The DCCA coefficient dominates the Pearson coefficient for non-stationary series.
Coefficient convexity of divisors of x^n-1
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.
International Nuclear Information System (INIS)
A novel parameterization of x-ray interaction cross-sections is developed, and employed to describe the x-ray linear attenuation coefficient and mass energy absorption coefficient for both elements and mixtures. The new parameterization scheme addresses the Z-dependence of elemental cross-sections (per electron) using a simple function of atomic number, Z. This obviates the need for a complicated mathematical formalism. Energy dependent coefficients describe the Z-direction curvature of the cross-sections. The composition dependent quantities are the electron density and statistical moments describing the elemental distribution. We show that it is possible to describe elemental cross-sections for the entire periodic table and at energies above the K-edge (from 6 keV to 125 MeV), with an accuracy of better than 2% using a parameterization containing not more than five coefficients. For the biologically important elements and the energy range 30- keV, the parameterization utilizes four coefficients. At higher energies, the parameterization uses fewer coefficients with only two coefficients needed at megavoltage energies
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.
Relations between coefficients of fractional parentage
International Nuclear Information System (INIS)
For each of the (9/2) (11/2), and (13/2) single j shells we have only one state with J=j v=3 for a five particle system. For four identical particles there can be more than one state of seniority four. We note some 'ratio' relations for the coefficients of fractional parentage for the four and five identical particle systems, which are found in the works of de Shalit and Talmi [Nuclear Shell Theory (Academic Press, New York, 1963)] and Talmi [Simple Models of Complex Nuclei (Harwood Academic, Reading, UK, 1993)] to be useful for explaining the vanishing of a five particle coefficients of fractional parentage (cfp). These relations are used to show that there is a special (g9/2)4 I=4 v=4 wave function that cannot be admixed with an I=4 v=2 wave function, even with seniority violating interactions
Electrochemical determination of partition coefficients of drugs.
Kontturi, K; Murtomäki, L
1992-10-01
An electrochemical method for the determination of partition coefficients of drugs that can exist as ions in aqueous solutions is presented. The method involves cyclic voltammetry at the polarizable interface between two immiscible electrolyte solutions. Because n-octanol is an unsuitable solvent for electrochemical purposes, 1,2-dichloroethane, which has electronic properties similar to those of n-octanol, was used in the measurements. The values obtained could be correlated with the values for n-octanol-water partition taken from the literature by an approach based on the linear solvation relationship: log P1 = a log P2 + b; in this relationship, a and b are constants and P1 and P2 correspond to the two different organic and aqueous phase partition equilibria. Furthermore, aqueous diffusion coefficients of drugs were determined from voltammograms. PMID:1432622
Rotational dissipation and the Miesowicz coefficients.
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
Doppler coefficient measurements in Zebra Core 5
International Nuclear Information System (INIS)
Measurements using a central hot loop in Zebra Core 5 are described. Results are given for the Doppler coefficients found in a number of assemblies with PuO2 and 16% PuO2/84% depleted UO2 pins, loaded with different combinations of steel, sodium or void pins. The mixed oxide results are in general about 20% more negative than was calculated using the FD2 data set, but agreement is good if the plutonium contributions in the calculations are omitted. The small positive Doppler coefficient calculated for Pu239 was not observed, and two measurements indicated instead a small negative effect. The Doppler effect in the mixed oxide systems was found to vary approximately as 1/T. The results from the empty loop and non-fissile assemblies indicate either a small negative Doppler effect in steel or alternatively the presence of an unexplained expansion effect. (author)
Testing the correlated random coefficient model
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...
LOSS COEFFICIENT DEPENDENCE OF TURBINE BLADE CASCADE
Czech Academy of Sciences Publication Activity Database
Matějka, M.; Šafařík, P.; Luxa, Martin; Šimurda, David; Synáč, J.
Glasgow: ASME, 2010, s. 1-9. ISBN 978-0-7918-4402-1. [ASME Turbo Expo 2010. Glasgow (GB), 14.06.2010-18.06.2010] R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR(CZ) IAA200760801 Institutional research plan: CEZ:AV0Z20760514 Keywords : loss coefficient * turbine cascade * pneumatic measurement Subject RIV: BK - Fluid Dynamics http://www.asmeconferences.org/TE10/ConfSpecInfo.cfm
Basketball Surfaces and Coefficient of Restitution
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...
Confidence Intervals for Cronbach's Coefficient Alpha Values
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 ...
Confidence Intervals for Cronbach's Coefficient Alpha Values
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 ...
Significane levels of linear correlation coefficients
International Nuclear Information System (INIS)
The determination of the significance (confidence) levels of linear correlation coefficients is discussed. Several methods which have been used in the analysis of channel correlations in nuclear physics are compared. A relatively new method, the bootstrap, is described and applied to a number of examples. Significance levels obtained with the different methods are usually comparable, but there are cases for which large differences exist. Reasons for these differences and the advantages of the bootstrap over previous methods are discussed. (orig.)
Recursive algorithms, branching coefficients and applications
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.
Sensitivity of the Heat Transfer Coefficient Calculation
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...
Efficient estimation of price adjustment coefficients
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...
Testing local versions of correlation coefficients
Kalogirou, Stamatis
2011-01-01
The aim of this paper is to define and test local versions of standard correlation coefficients in statistical analysis. This research is motivated by the increasing number of applications using local versions of exploratory and explanatory spatial data analysis methods. A common example of the latter is local regression. Methods such as the Geographically Weighted Regression argue that it is necessary to check spatial non-stationarity in the relationships between a geographic phenomenon and ...
Correlation and prediction of gaseous diffusion coefficients.
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.
On the Central Coefficients of Riordan Matrices
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...
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.
AN EXHAUSTIVE COEFFICIENT OF RANK CORRELATION
Agostino Tarsitano; Rosetta Lombardo
2011-01-01
Rank association is a fundamental tool for expressing dependence in cases in which data are arranged in order. Measures of rank correlation have been accumulated in several contexts for more than a century and we were able to cite more than thirty of these coefficients, from simple ones to relatively complicated definitions invoking one or more systems of weights. However, only a few of these can actually be considered to be admissible substitutes for Pearson’s correlation. The main drawback ...
Fresnel coefficients for a layer of NIM
International Nuclear Information System (INIS)
Reflection and transmission of traveling and evanescent waves by a layer of material with a negative index of refraction (NIM) is studied by means of the Fresnel coefficients. We derive their values in the “NIM limit”, and we show that this limit is consistent with the exact solution. It is also indicated that simply substituting the negative values of the relative permittivity and permeability of the NIM material into the exact solution leads to incorrect results for evanescent waves.
Seebeck coefficients of half-metallic ferromagnets
Balke, Benjamin; OUARDI, SIHAM; Graf, Tanja; Barth, Joachim; Blum, Christian G. F.; FECHER, GERHARD H.; Shkabko, Andrey; Weidenkaff, Anke; Felser, Claudia
2009-01-01
In this report the Co2 based Heusler compounds are discussed as potential materials for spin voltage generation. The compounds were synthesized by arcmelting and consequent annealing. Band structure calculations were performed and revealed the compounds to be half-metallic ferromagnets. Magnetometry was performed on the samples and the Curie temperatures and the magnetic moments were determined. The Seebeck coefficients were measured from low to ambient temperatures for all compounds. For sel...
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.
Thin film description by wavelet coefficients statistics
Czech Academy of Sciences Publication Activity Database
Boldyš, Jiří; Hrach, R.
2005-01-01
Roč. 55, č. 1 (2005), s. 55-64. ISSN 0011-4626 Grant ostatní: GA UK(CZ) 173/2003 Institutional research plan: CEZ:AV0Z10750506 Keywords : thin films * wavelet transform * descriptors * histogram model Subject RIV: BD - Theory of Information Impact factor: 0.360, year: 2005 http://library.utia.cas.cz/separaty/2009/ZOI/boldys-thin film description by wavelet coefficients statistics .pdf
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)
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)
Feedback reactivity coefficients and their coupling
International Nuclear Information System (INIS)
Coupled reactivity feedback coefficients which accounts for variation in fuel temperature and moderator void simultaneously, have been determined for swimming pool type research reactor namely Pakistan Research Reactor PARR-1. The state of art is core criticality calculations, employing lattice cell code WIMS-D/4 and application of Taylor series expansion for core reactivity up to third order, involving two variables, i.e. fuel temperature and coolant void. The spectral effects in one region due to change of parameter in other region have also been studied. When spectral changes in moderator region due to 20 K change in fuel temperature have been incorporated in the calculation of fuel temperature coefficient, the results seems to be improved by 4.12%. Further, the results of void coefficient of reactivity show the improvement of 0.1% when the spectral effect in fuel region due to 5% change in void in moderator region is taken into account. These differences seem to be an improvement in the results, as physically any change in one region is accompanied by change in the other region
Feedback reactivity coefficients and their coupling
Energy Technology Data Exchange (ETDEWEB)
Khan, Rustam [Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad (Pakistan)]. E-mail: rustamzia@yahoo.com; Hamid, Tehsin [Directorate of Safety, P.O. Box 1114, Islamabad (Pakistan); Bakhtyar, Sabiha [Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)
2007-05-15
Coupled reactivity feedback coefficients which accounts for variation in fuel temperature and moderator void simultaneously, have been determined for swimming pool type research reactor namely Pakistan Research Reactor PARR-1. The state of art is core criticality calculations, employing lattice cell code WIMS-D/4 and application of Taylor series expansion for core reactivity up to third order, involving two variables, i.e. fuel temperature and coolant void. The spectral effects in one region due to change of parameter in other region have also been studied. When spectral changes in moderator region due to 20 K change in fuel temperature have been incorporated in the calculation of fuel temperature coefficient, the results seems to be improved by 4.12%. Further, the results of void coefficient of reactivity show the improvement of 0.1% when the spectral effect in fuel region due to 5% change in void in moderator region is taken into account. These differences seem to be an improvement in the results, as physically any change in one region is accompanied by change in the other region.
Analysis of flow coefficient in chair manufacture
Directory of Open Access Journals (Sweden)
Ivković Dragoljub
2005-01-01
Full Text Available The delivery on time is not possible without the good-quality planning of deadlines, i.e. planning of the manufacturing process duration. The study of flow coefficient enables the realistic forecasting of the manufacturing process duration. This paper points to the significance of the study of flow coefficient on scientific basis so as to determine the terms of the end of the manufacture of chairs made of sawn timber. Chairs are the products of complex construction, often almost completely made of sawn timber as the basic material. They belong to the group of export products, so it is especially significant to analyze the duration of the production cycle, and the type and the degree of stoppages in this type of production. Parallel method of production is applied in chair manufacture. The study shows that the value of flow coefficient is close to one or higher, in most cases. The results indicate that the percentage of interoperational stoppage is unjustifiably high, so it is proposed how to decrease the percentage of stoppages in the manufacturing process.
The Phi-coefficient, the Tetrachoric Correlation Coefficient, and the Pearson-Yule Debate
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...
Tests of Hypotheses Arising in the Correlated Random Coefficient Model
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.
Measuring correlations between non-stationary series with DCCA coefficient
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...
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.
Transport coefficients of He(+) ions in helium.
Viehland, Larry A; Johnsen, Rainer; Gray, Benjamin R; Wright, Timothy G
2016-02-21
This paper demonstrates that the transport coefficients of (4)He(+) in (4)He can be calculated over wide ranges of E/N, the ratio of the electrostatic field strength to the gas number density, with the same level of precision as can be obtained experimentally if sufficiently accurate potential energy curves are available for the X(2)Σu (+) and A(2)Σg (+) states and one takes into account resonant charge transfer. We start by computing new potential energy curves for these states and testing their accuracy by calculating spectroscopic values for the separate states. It is established that the potentials obtained by extrapolation of results from d-aug-cc-pVXZ (X = 6, 7) basis sets using the CASSCF+MRCISD approach are each in exceptionally close agreement with the best potentials available and with experiment. The potentials are then used in a new computer program to determine the semi-classical phase shifts and the transport cross sections, and from these the gaseous ion transport coefficients are determined. In addition, new experimental values are reported for the mobilities of (4)He(+) in (4)He at 298.7 K, as a function of E/N, where careful consideration is given to minimizing various sources of uncertainty. Comparison with previously measured values establishes that only one set of previous data is reliable. Finally, the experimental and theoretical ion transport coefficients are shown to be in very good to excellent agreement, once corrections are applied to account for quantum-mechanical effects. PMID:26896985
Control in the coefficients with variational crimes
DEFF Research Database (Denmark)
Evgrafov, Anton; Marhadi, Kun Saptohartyadi
2012-01-01
fourth order. Methods which do not require approximation subspaces to conform to the smoothness requirements dictated by the PDE are very attractive for such problems. However, variational formulations of such methods normally contain boundary integrals whose dependence on the small, with respect to...... “volumetric” Lebesgue norm, changes of the coefficients is generally speaking not continuous. We utilize the lifting formulation of the discontinuous Galerkin method to deal with this issue.Our main result is that limit points of sequences of designs verifying discrete versions of stationarity can also be...
Measuring subdiffusion parameter and subdiffusion coefficient
International Nuclear Information System (INIS)
We derive theoretical formulas which allow one to extract the subdiffusion parameter α and subdiffusion coefficient Dα form measured concentration profiles of transported substance in a subdiffusive medium. The parameters occur in the relation defining the subdiffusion 2> = 2Dαtα/[Γ(1+α)] with α 2> denotes the mean-square displacement of a Brownian particle. The analysis is performed separately for the medium, where optical measurements of concentrations are possible (the medium is transparent for a laser beam), as well as for the non-transparent medium. (author)
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
Semiclassical OPE coefficients from 3D gravity
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.
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
Kinetic coefficients for quark-antiquark plasma
International Nuclear Information System (INIS)
The quark-antiquark plasma near equilibrium is studied. The results are based on the Heinz kinetic equations with the Boltzmann collision operator approximated by a relaxation term with the relaxation time, τ, treated as a small parameter. Linear in τ solutions of these equations are used to calculate the transport coefficients: the non-abelian version of Ohm's law, and the shear and volume viscosities. We introduce new chemical potentials which determine the color density matrix of quarks (antiquarks). Gradients of these potentials generate color currents. 12 refs. (author)
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....... In the case of strong pore diffusion limitations, the error in the interpretation of experimental results using the mean pore radius could be a factor of 5 on the intrinsic rate constant. For an average coal char reacting with oxygen at 1300 K, this would be the case for particle sizes larger than...
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.
Studies of Gaseous Multiplication Coefficient in Isobutane
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.
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.
Mass Accomodation Coefficient for Nanoscale Aerosol Particles
Czech Academy of Sciences Publication Activity Database
Levdansky, Valerij Vladimirovič; Smolík, Jiří; Ždímal, Vladimír; Moravec, Pavel
Praha : Česká aerosolová společnost, 2012 - (Vodička, P.; Zíková, N.), s. 75-76 ISBN 978-80-86186-40-5. [Výroční konference České aerosolové společnosti /13./. Třeboň (CZ), 25.10.2012-26.10.2012] R&D Projects: GA ČR GA101/09/1633; GA AV ČR IAA200760905 Institutional support: RVO:67985858 Keywords : nanoparticles * size effect * mass accommodation coefficient Subject RIV: CF - Physical ; Theoretical Chemistry
Transport coefficients of a hot pion gas
International Nuclear Information System (INIS)
General expressions for transport coefficients of a single component gas (namely thermal conductivity, shear and bulk viscosities) of bosons are derived from a Boltzmann-Uehling-Uhlenbeck transport equation by means of the Chapman-Enskog method to first order. These expressions are then used for the calculation of the associated transport relaxation times and applied to the pion gas produced in ultra-relativistic heavy-ion collisions. The influence of Bose enhancement factors on transport properties can be seen by comparison with previous calculations. (authors)
Link prediction with node clustering coefficient
Wu, Zhihao; Lin, Youfang; Wang, Jing; Gregory, Steve
2016-06-01
Predicting missing links in incomplete complex networks efficiently and accurately is still a challenging problem. The recently proposed Cannistrai-Alanis-Ravai (CAR) index shows the power of local link/triangle information in improving link-prediction accuracy. Inspired by the idea of employing local link/triangle information, we propose a new similarity index with more local structure information. In our method, local link/triangle structure information can be conveyed by clustering coefficient of common-neighbors directly. The reason why clustering coefficient has good effectiveness in estimating the contribution of a common-neighbor is that it employs links existing between neighbors of a common-neighbor and these links have the same structural position with the candidate link to this common-neighbor. In our experiments, three estimators: precision, AUP and AUC are used to evaluate the accuracy of link prediction algorithms. Experimental results on ten tested networks drawn from various fields show that our new index is more effective in predicting missing links than CAR index, especially for networks with low correlation between number of common-neighbors and number of links between common-neighbors.
Wavelet Cesptral Coefficients for Isolated Speech Recognition
Directory of Open Access Journals (Sweden)
T. B. Adam
2013-05-01
Full Text Available The study proposes an improved feature extraction method that is called Wavelet Cepstral Coefficients (WCC. In traditional cepstral analysis, the cepstrums are calculated with the use of the Discrete Fourier Transform (DFT. Owing to the fact that the DFT calculation assumes signal stationary between frames which in practice is not quite true, the WCC replaces the DFT block in the traditional cepstrum calculation with the Discrete Wavelet Transform (DWT hence producing the WCC. To evaluate the proposed WCC, speech recognition task of recognizing the 26 English alphabets were conducted. Comparisons with the traditional Mel-Frequency Cepstral Coefficients (MFCC are done to further analyze the effectiveness of the WCCs. It is found that the WCCs showed some comparable results when compared to the MFCCs considering the WCCs small vector dimension when compared to the MFCCs. The best recognition was found from WCCs at level 5 of the DWT decomposition with a small difference of 1.19% and 3.21% when compared to the MFCCs for speaker independent and speaker dependent tasks respectively.
Ionization coefficient measurements in DC microplasmas
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
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)
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
Estimating biokinetic coefficients in the PACT™ system.
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
A new coefficient of concordance with applications to biosignal analysis
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.
Questionnaire discrimination: (re-introducing coefficient δ
Directory of Open Access Journals (Sweden)
Hankins Matthew
2007-05-01
Full Text Available Abstract Background Questionnaires are used routinely in clinical research to measure health status and quality of life. Questionnaire measurements are traditionally formally assessed by indices of reliability (the degree of measurement error and validity (the extent to which the questionnaire measures what it is supposed to measure. Neither of these indices assesses the degree to which the questionnaire is able to discriminate between individuals, an important aspect of measurement. This paper introduces and extends an existing index of a questionnaire's ability to distinguish between individuals, that is, the questionnaire's discrimination. Methods Ferguson (1949 1 derived an index of test discrimination, coefficient δ, for psychometric tests with dichotomous (correct/incorrect items. In this paper a general form of the formula, δG, is derived for the more general class of questionnaires allowing for several response choices. The calculation and characteristics of δG are then demonstrated using questionnaire data (GHQ-12 from 2003–2004 British Household Panel Survey (N = 14761. Coefficients for reliability (α and discrimination (δG are computed for two commonly-used GHQ-12 coding methods: dichotomous coding and four-point Likert-type coding. Results Both scoring methods were reliable (α > 0.88. However, δG was substantially lower (0.73 for the dichotomous coding of the GHQ-12 than for the Likert-type method (δG = 0.96, indicating that the dichotomous coding, although reliable, failed to discriminate between individuals. Conclusion Coefficient δG was shown to have decisive utility in distinguishing between the cross-sectional discrimination of two equally reliable scoring methods. Ferguson's δ has been neglected in discussions of questionnaire design and performance, perhaps because it has not been implemented in software and was restricted to questionnaires with dichotomous items, which are rare in health care research. It is
ROUGHNESS COEFFICIENT FOR UNSUBMERGED AND SUBMERGED REED
Institute of Scientific and Technical Information of China (English)
无
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.
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)
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.
Thermal Conductivity Coefficient from Microscopic Models
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.
Molar extinction coefficients of some fatty acids
DEFF Research Database (Denmark)
Sandhu, G.K.; Singh, K.; Lark, B.S.;
2002-01-01
) and stearic acid (C18H36O2), 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......The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...
Distortion effects on the spin transfer coefficient
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.
Effective Electrocardiogram Steganography Based on Coefficient Alignment.
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. PMID:26711443
Adler, Jeremy; Parmryd, Ingela
2010-08-01
The Pearson correlation coefficient (PCC) and the Mander's overlap coefficient (MOC) are used to quantify the degree of colocalization between fluorophores. The MOC was introduced to overcome perceived problems with the PCC. The two coefficients are mathematically similar, differing in the use of either the absolute intensities (MOC) or of the deviation from the mean (PCC). A range of correlated datasets, which extend to the limits of the PCC, only evoked a limited response from the MOC. The PCC is unaffected by changes to the offset while the MOC increases when the offset is positive. Both coefficients are independent of gain. The MOC is a confusing hybrid measurement, that combines correlation with a heavily weighted form of co-occurrence, favors high intensity combinations, downplays combinations in which either or both intensities are low and ignores blank pixels. The PCC only measures correlation. A surprising finding was that the addition of a second uncorrelated population can substantially increase the measured correlation, demonstrating the importance of excluding background pixels. Overall, since the MOC is unresponsive to substantial changes in the data and is hard to interpret, it is neither an alternative to nor a useful substitute for the PCC. The MOC is not suitable for making measurements of colocalization either by correlation or co-occurrence. PMID:20653013
Verifying reciprocal relations for experimental diffusion coefficients in multicomponent mixtures
DEFF Research Database (Denmark)
Medvedev, Oleg; Shapiro, Alexander
2003-01-01
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......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...... diffusion coefficients into Onsager coefficients for a non-ideal mixture involves derivatives of the chemical potentials and, thus, should be based on a certain thermodynamic model (cubic equation of state (EoS), an activity coefficient model, etc.). Transformation of the Fickian diffusion coefficients into...
Recovering DC coefficients in block-based DCT.
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
The Attenuation of Correlation Coefficients: A Statistical Literacy Issue
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.
Global cycle properties in graphs with large minimum clustering coefficient
Borchert, Adam; Nicol, Skylar; Oellermann, Ortrud R.
2015-01-01
The clustering coefficient of a vertex in a graph is the proportion of neighbours of the vertex that are adjacent. The minimum clustering coefficient of a graph is the smallest clustering coefficient taken over all vertices. A complete structural characterization of those locally connected graphs, with minimum clustering coefficient 1/2 and maximum degree at most 6, that are fully cycle extendable is given in terms of strongly induced subgraphs with given attachment sets. Moreover, it is show...
EXACT SAMPLING DISTRIBUTION OF SAMPLE COEFFICIENT OF VARIATION
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...
PEARSON'S OR SPEARMAN'S CORRELATION COEFFICIENT - WHICH ONE TO USE?
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...
Estimating crop coefficients from fraction of ground cover and height
Richard G. Allen; 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....
The photon attenuation coefficients of barite, marble and limra
International Nuclear Information System (INIS)
The linear attenuation coefficients μ (cm-1) and total mass attenuation coefficients ((μ)/(ρ)) (cm2 g-1) of γ-rays for barite, marble and limra have been calculated using the XCOM program (Version 3.1) at energies from 1 keV to 300 MeV. The calculated results were compared with the estimation coefficients ((μ)/(ρ)) based on the measured total linear attenuation coefficients (μ)
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.``
My Current Thoughts on Coefficient Alpha and Successor Procedures
Cronbach, Lee J.; Shavelson, Richard J.
2004-01-01
In 1997, noting that the 50th anniversary of the publication of "Coefficient Alpha and the Internal Structure of Tests" was fast approaching, Lee Cronbach planned what have become the notes published here. His aim was to point out the ways in which his views on coefficient alpha had evolved, doubting now that the coefficient was the best way of…
Microscopic formula for transport coefficients of causal hydrodynamics
Koide, T.
2007-01-01
The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics because of the problem of acausality and the breaking of sum rules. In this work, we propose a formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient, and corresponding relaxation times.
Interpretation of Standardized Regression Coefficients in Multiple Regression.
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…
On the Occurrence of Standardized Regression Coefficients Greater than One.
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…
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)
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...
On some properties of SU(3) Fusion Coefficients
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.
Transport coefficients of a relativistic plasma
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.
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)
Ghost imaging based on Pearson correlation coefficients
Yu, Wen-Kai; Yao, Xu-Ri; Liu, Xue-Feng; Li, Long-Zhen; Zhai, Guang-Jie
2015-05-01
Correspondence imaging is a new modality of ghost imaging, which can retrieve a positive/negative image by simple conditional averaging of the reference frames that correspond to relatively large/small values of the total intensity measured at the bucket detector. Here we propose and experimentally demonstrate a more rigorous and general approach in which a ghost image is retrieved by calculating a Pearson correlation coefficient between the bucket detector intensity and the brightness at a given pixel of the reference frames, and at the next pixel, and so on. Furthermore, we theoretically provide a statistical interpretation of these two imaging phenomena, and explain how the error depends on the sample size and what kind of distribution the error obeys. According to our analysis, the image signal-to-noise ratio can be greatly improved and the sampling number reduced by means of our new method. Project supported by the National Key Scientific Instrument and Equipment Development Project of China (Grant No. 2013YQ030595) and the National High Technology Research and Development Program of China (Grant No. 2013AA122902).
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.
Local diffusion coefficient determination: Mediterranean Sea experiments
International Nuclear Information System (INIS)
The Mediterranean is a semi/enclosed basin characterized by the presence of channels and straits influencing the circulation, temperature and salinity fields. The tides generally have amplitudes of the order of 10 cm and velocities of few cm/s. Conversely, the wind forced circulation is very strong and can assume velocity values of 1 m/s at the sea surface. The temperature and salinity fields have a high temporal and spatial variability, because of many mixing processes existing in the sea. For example, the waters coming from the Provencal basin meet those waters coming from the Tyrrhenian Sea in the eastern Ligurian Sea, creating meanders and eddies. Local runoff influences significantly the coastal circulation. This paper describes diffusion experiments carried out in this complex environment. The experimental apparatus for the detection of the fluorescine released at sea was composed by two Turner mod. 450 fluorometres. During the experiments, temperature and salinity vertical profiles were measured by using a CTD; meteorological data were acquired on a dinghy. The positioning was obtained by means of a Motorola system, having a precision of about 1 meter. The experiments were carried out under different stratification and wind conditions. From data analysis it was found that the horizontal diffusion coefficient does not depend on time or boundary conditions. The role of stratification is important with regard to vertical displacement of the dye. However, its role with regard to vertical diffusion cannot be assessed with the actual experimental apparatus
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.)
Transfer coefficients for terrestrial foodchain: their derivation and limitations
International Nuclear Information System (INIS)
Transfer coefficients to predict the passage of isotopes from the environment to terrestrial foods have been derived for various radionuclides of importance in the nuclear fuel cycle. These data update and extend previously recommended handbook values. We derive transfer coefficients to terrestrial foods and describe the systematics of the derived transfer coefficients. Suggestions are offered for changes in the values of transfer coefficients to terrestrial foods that now appear in federal regulatory guides. Deficiencies in our present knowledge concerning transfer coefficients and limitations in the use of these values to ensure compliance with radiation protection standards are discussed
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Ih, Jeong-Guon; Rindel, Jens Holger
The phased beam tracing method (PBTM) is a technique which can calculate the pressure impulse response instead of energy impulse response, by taking the phase information into account. Inclusion of the phase information can extend the application of beam tracing technique to the mid frequency range...... in spite of the fact that the usual assumptions of geometric acoustics still hold. In the calculation of pressure impulse response, it is essential to have the reflection characteristics of the surfaces in the enclosed space. There is a method to obtain the reflection coefficient of the surface using...... the measured surface impedance. However, it is not always possible to get the measured impedance data of the surface, so that a practical way of getting reflection characteristics is needed. Generally, in the architectural acoustics field, the absorption coefficients have been employed in the...
International Nuclear Information System (INIS)
Highlights: ► Kerma is essential for nuclear medicine, diagnostics and radiation dosimeter. ► The values of μm and μe/ρ depends on the photon energy and chemical content of vitamins. ► New experiments should be performed to study physical parameters of biomolecules. -- Abstract: The mass attenuation coefficients for some vitamins (retinol, beta-carotene, thiamine, riboflavin, niacinamide, pantothenic acid, pyridoxine, biotin, folic acid, cyanocobalamin, ascorbic acid, cholecalciferol, alpha-tocopherol, ketamine, hesperidin) were determined experimentally and theoretically at 356.61, 661.66, 1250 and 1408.01 keV photon energies by using a NaI(Tl) scintillation detector. Also, the mass energy absorption coefficients and kerma have been calculated. The calculated values were compared with the semi-empirical values for vitamins.
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.
Abney, Mark
2009-01-01
Summary: Computing the probability of identity by descent sharing among n genes given only the pedigree of those genes is a computationally challenging problem, if n or the pedigree size is large. Here, I present a novel graphical algorithm for efficiently computing all generalized kinship coefficients for n genes. The graphical description transforms the problem from doing many recursion on the pedigree to doing a single traversal of a structure referred to as the kinship graph.
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.
Linear and nonlinear optical absorption coefficients of spherical dome shells
Guo, Kangxian; Liu, Guanghui; Huang, Lu; Zheng, Xianyi
2015-08-01
Linear and nonlinear optical absorption coefficients of spherical dome shells are theoretically investigated within analytical wave functions and numerical quantized energy levels. Our results show that the inner radius, the outer radius and the cut-off angle of spherical dome shells have great influences on linear and nonlinear optical absorption coefficients as well as the total optical absorption coefficients. It is found that with the increase of the inner radius and the outer radius, linear and nonlinear optical absorption coefficients exhibit a blueshift and a redshift, respectively. However, with the increase of the cut-off angle, linear and nonlinear optical absorption coefficients do not shift. Besides, the resonant peaks of linear and nonlinear optical absorption coefficients climb up and then decrease with increasing the cut-off angle. The influences of the incident optical intensity on the total optical absorption coefficients are studied. It is found that the bleaching effect occurs at higher incident optical intensity.
Methods for Accurate Free Flight Measurement of Drag Coefficients
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)...
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)
Personal dose-equivalent conversion coefficients for 1252 radionuclides.
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. PMID:25349458
Fusion of Daubechies Wavelet Coefficients for Human Face Recognition
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...
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.
Degree and clustering coefficient in sparse random intersection graphs
Bloznelis, Mindaugas
2013-01-01
We establish asymptotic vertex degree distribution and examine its relation to the clustering coefficient in two popular random intersection graph models of Godehardt and Jaworski [Electron. Notes Discrete Math. 10 (2001) 129–132]. For sparse graphs with a positive clustering coefficient, we examine statistical dependence between the (local) clustering coefficient and the degree. Our results are mathematically rigorous. They are consistent with the empirical observation of Foudalis et al. [In...
Zero Pearson Coefficient for Strongly Correlated Growing Trees
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...
A Meta-analysis of Cronbach's Coefficient Alpha.
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...
Consideration on Singularities in Learning Theory and the Learning Coefficient
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...
Coefficient of restitution of model repaired car body parts
D. Hadryś; M. Miros
2008-01-01
Purpose: The qualification of influence of model repaired car body parts on the value of coefficient of restitution and evaluation of impact energy absorption of model repaired car body parts.Design/methodology/approach: Investigation of plastic strain and coefficient of restitution of new and repaired model car body parts with using impact test machine for different impact energy.Findings: The results of investigations show that the value of coefficient of restitution changes with speed (ene...
Microscopic formula of transport coefficients for causal hydrodynamics
Koide, T
2007-01-01
The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics, because of the problem of acausality and the breaking of sum rules. In this work, we propose a new formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient and corresponding relaxation times.
DCFPAK: Dose coefficient data file package for Sandia National Laboratory
Energy Technology Data Exchange (ETDEWEB)
Eckerman, K.F.; Leggett, R.W.
1996-07-31
The FORTRAN-based computer package DCFPAK (Dose Coefficient File Package) has been developed to provide electronic access to the dose coefficient data files summarized in Federal Guidance Reports 11 and 12. DCFPAK also provides access to standard information regarding decay chains and assembles dose coefficients for all dosimetrically significant radioactive progeny of a specified radionuclide. DCFPAK was designed for application on a PC but, with minor modifications, may be implemented on a UNIX workstation.
AN ALTERNATIVE RANK CORRELATION COEFFICIENT WİTH GRAPHICAL APPROXIMATION
ÖZDEMİR, Yaprak Arzu; EKİZ, Meltem
2010-01-01
ABSTRACTIn this study, a rank correlation coefficient (v) proposed by Blest(2000), which does not require normality assumption in hypothesis testing of correlation coefficient for interval level or ratio scaled measured variables, is introduced. This rank correlation coefficient, which is examined based on graphical presentation and their comments, has a structure, which considers the interchanges in the early ranking of the data. When the sample size is five this introduced v rank corr...
SLE_k: correlation functions in the coefficient problem
Loutsenko, Igor
2012-01-01
We apply the method of correlation functions to the coefficient problem in stochastic geometry. In particular, we give a proof for some universal patterns conjectured by M. Zinsmeister for the second moments of the Taylor coefficients for special values of kappa in the whole-plane Schramm-Loewner evolution (SLE_kappa). We propose to use multi-point correlation functions for the study of higher moments in coefficient problem. Generalizations related to the Levy-type processes are also consider...
Wavelet Correlation Coefficient of 'strongly correlated' financial time series
Ashok Razdan
2003-01-01
In this paper we use wavelet concepts to show that correlation coefficient between two financial data's is not constant but varies with scale from high correlation value to strongly anti-correlation value This studies is important because correlation coefficient is used to quantify degree of independence between two variables. In econophysics correlation coefficient forms important input to evolve hierarchial tree and minimum spanning tree of financial data.
A new approach to bootstrap inference in functional coefficient models
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...
Optimization of coefficients of lists of polynomials by evolutionary algorithms
Sendra Pons, Juan Rafael; Winkler, Stephan M.
2015-01-01
We here discuss the optimization of coefficients of lists of polynomials using evolutionary computation. The given polynomials have 5 variables, namely t, a1, a2, a3, a4, and integer coefficients. The goal is to find integer values i, with i 2 {1, 2, 3, 4}, substituting ai such that, after crossing out the gcd (greatest common divisor) of all coefficients of the polynomials, the resulting integers are minimized in absolute value. Evolution strategies, a special class of heu...
Some comments on `Equation for the second virial coefficient`
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...
Testing the heteroscedastic error structure in quantile varying coefficient models
Gijbels, Irène; Ibrahim, Mohammed; Verhasselt, Anneleen
2015-01-01
Regression quantiles generalize naturally mean regression for Gaussian linear models, while substantially out-performing the least-squares estimator over a wide class of nonGaussian error distributions. Varying coefficient models (VCMs) are considered, they are an extension of classical linear regression models that allow the coefficients to depend on other variables. Assuming longitudinal data, the regression coefficients are allowed to vary with time. We consider VCMs with various struct...
A Semiparametric Recurrent Events Model with Time-varying Coefficients
Yu, Zhangsheng; Liu, Lei; Bravata, Dawn M.; Williams, Linda S.; Tepper, Robert S.
2012-01-01
We consider a recurrent events model with time-varying coefficients motivated by two clinical applications. A random effects (Gaussian frailty) model is used to describe the intensity of recurrent events. The model can accommodate both time-varying and time-constant coefficients. The penalized spline method is used to estimate the time-varying coefficients. Laplace approximation is used to evaluate the penalized likelihood without a closed form. The smoothing parameters are ...
Fresnel coefficients of a two-dimensional atomic crystal
Merano, Michele
2015-01-01
In general the experiments on the linear optical properties of a single-layer two-dimensional atomic crystal are interpreted by modeling it as a homogeneous slab with an effective thickness. Here I fit the most remarkable experiments in graphene optics by using the Fresnel coefficients, fixing both the surface susceptibility and the surface conductivity of graphene. It is shown that the Fresnel coefficients and the slab model are not equivalent. Experiments indicate that the Fresnel coefficie...
Cluster automorphism groups of cluster algebras with coefficients
Chang, Wen; Zhu, Bin
2015-01-01
We study the cluster automorphism group of a skew-symmetric cluster algebra with geometric coefficients. For this, we introduce the notion of gluing free cluster algebra, and show that under a weak condition the cluster automorphism group of a gluing free cluster algebra is a subgroup of the cluster automorphism group of its principal part cluster algebra (i.e. the corresponding cluster algebra without coefficients). We show that several classes of cluster algebras with coefficients are gluin...
ON TESTING THE EQUALITY OF K MULTIPLEAND PARTIAL CORRELATION COEFFICIENTS
Institute of Scientific and Technical Information of China (English)
无
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.
Numerical calculation of the transport coefficients in thermal plasmas
Mahfouf, Ali; André, Pascal; Faure, Géraldine
2014-01-01
-We have performed a new efficient method to calculate numerically the transport coefficients at high temperature. The collision theory was treated to study singularities that occur when evaluating the collision cross section. The transport coefficients (viscosity, diffusion coefficient, thermal and electrical conductivity) depend strongly on nature of the interaction between the particles that form the plasma and that is why it is necessary to determine the interaction potential accurately.
Estimating Crop Coefficients Using Remote Sensing-Based Vegetation Index
Kenneth Hubbard; Baburao Kamble; Ayse Kilic
2013-01-01
Crop coefficient (Kc)-based estimation of crop evapotranspiration is one of the most commonly used methods for irrigation water management. However, uncertainties of the generalized dual crop coefficient (Kc) method of the Food and Agricultural Organization of the United Nations Irrigation and Drainage Paper No. 56 can contribute to crop evapotranspiration estimates that are substantially different from actual crop evapotranspiration. Similarities between the crop coefficient curve and a sate...
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.
Local heat transfer coefficient for turbulent flow in rod bundles
International Nuclear Information System (INIS)
The correlation of the local heat transfer coefficients in heated triangular array of rod bundles, in terms of the flow hydrodynamic parameters is presented. The analysis is made first for fluid with Prandtl numbers varying from moderated to high (Pr>0.2), and then extended to fluids with low Prandtl numbers (0.004< Pr<0.2). Results of temperature and velocity fields distribution of slip coefficients and local heat transfer coefficients are obtained. (E.G.)
Investigating Diffusion Coefficient Using Dynamic Light Scattering Technique
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...
Measurement of crack length by ultrasonic attenuation coefficient
International Nuclear Information System (INIS)
In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for Double-Cantilever Beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the crack length for the ultrasonic attenuation coefficient and energy release rate is increases proportionally. From the experimental results, we proposed a detecting method of the crack length by the ultrasonic attenuation coefficient and discussed it
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.
Kinetic theory of the interdiffusion coefficient in dense plasmas
International Nuclear Information System (INIS)
Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs
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.
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.
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.
Explicit solutions of two nonlinear dispersive equations with variable coefficients
International Nuclear Information System (INIS)
A mathematical technique based on an auxiliary equation and the symbolic computation system Matlab is developed to construct the exact solutions for a generalized Camassa-Holm equation and a nonlinear dispersive equation with variable coefficients. It is shown that the variable coefficients of the derivative terms in the equations cause the qualitative change in the physical structures of the solutions
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.
Oscillations in linear difference equations with variable coefficients
Directory of Open Access Journals (Sweden)
Ch. G. Philos
1991-01-01
Full Text Available A class of linear difference equations with variable coefficients is considered. Sufficient conditions and necessary conditions for the oscillation of the solutions are established. In the special cases where the coefficients are constant or periodic the conditions become both necessary and sufficient.
Anderson-Witting transport coefficients for flows in general relativity
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.
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 Univer...
Delimiting Coefficient a from Internal Consistency and Unidimensionality
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…
Calculation of fusion product angular correlation coefficients for fusion plasmas
International Nuclear Information System (INIS)
The angular correlation coefficients for fusion products are calculated in the cases of Maxwellian and beam-target plasmas. Measurement of these coefficients as a localized ion temperature or fast-ion diagnostic is discussed. 8 refs., 7 figs., 1 tab
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)
Heavy Quark Momentum Diffusion Coefficient from Lattice QCD
Banerjee, Debasish; Datta, Saumen; Gavai, Rajiv; Majumdar, Pushan
2011-01-01
The momentum diffusion coefficient for heavy quarks is studied in a deconfined gluon plasma in the static approximation by investigating a correlation function of the color electric field using Monte Carlo techniques. The diffusion coefficient is extracted from the long distance behavior of such a correlator. For temperatures Tc < T
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...
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....
The Use of Structure Coefficients in Regression Research.
Perry, Lucille N.
It is recognized that parametric methods (e.g., t-tests, discriminant analysis, and methods based on analysis of variance) are special cases of canonical correlation analysis. In canonical correlation it has been argued that structure coefficients must be computed to correctly interpret results. It follows that structure coefficients may be useful…
The Fresnel coefficients of a two-dimensional atomic crystal
Merano, Michele
2016-01-01
I deduce the Fresnel coefficients valid for a generic two dimensional crystal. In general the optical properties of an atomically thin monolayer are interpreted by modelling it as a homogeneous medium with an effective thickness. The comparison with experimental results, published in literature, shows that the Fresnel coefficients are better suited to this end than the above mentioned model.
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.
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....
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 that...
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.
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.
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
Uncertainty in wind pressure coefficients for low-rise buildings
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
Crop Coefficients of Some Selected Crops of Andhra Pradesh
Reddy, K. Chandrasekhar; Arunajyothy, S.; Mallikarjuna, P.
2015-06-01
Precise information on crop coefficients for estimating crop evapotranspiration (ETc) for regional scale irrigation planning is a major impediment in many regions. Crop coefficients suggested based on lysimeter data by earlier investigators have to be locally calibrated to account for the differences in the crop canopy under given climatic conditions. In the present study crop coefficients were derived based on reference crop evapotranspiration (ET0) estimated from Penman-Monteith equation and lysimeter measured ETc for groundnut, paddy, tobacco, sugarcane and castor crops at Tirupati, Nellore, Rajahmundry, Anakapalli and Rajendranagar centers of Andhra Pradesh respectively. Crop coefficients derived were compared with those recommended by FAO-56. The mean crop coefficients at different stages of growth were significantly different from those of FAO-56 curve though a similar trend was observed. A third order polynomial crop coefficient model has therefore been developed as a function of time (days after sowing the crop) for deriving suitable crop coefficients. The crop coefficient models suggested may be adopted to estimate crop evapotranspiration in the study area with reasonable degree of accuracy.
Crop coefficient development and application to an evapotranspiration network
Crop coefficients derived from properly designed, operated, and maintained lysimeters provide the most accurate values throughout the growing season and are critical in the computation of hourly and daily,regionally based, crop evapotranspiration (ET) values. Multi-stage crop coefficients can be der...
A new correlation coefficient for bivariate time-series data
Erdem, Orhan; Ceyhan, Elvan; Varli, Yusuf
2014-11-01
The correlation in time series has received considerable attention in the literature. Its use has attained an important role in the social sciences and finance. For example, pair trading in finance is concerned with the correlation between stock prices, returns, etc. In general, Pearson’s correlation coefficient is employed in these areas although it has many underlying assumptions which restrict its use. Here, we introduce a new correlation coefficient which takes into account the lag difference of data points. We investigate the properties of this new correlation coefficient. We demonstrate that it is more appropriate for showing the direction of the covariation of the two variables over time. We also compare the performance of the new correlation coefficient with Pearson’s correlation coefficient and Detrended Cross-Correlation Analysis (DCCA) via simulated examples.
Determination of absolute internal conversion coefficients using the SAGE spectrometer
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.
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)
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.
Diffusion coefficient adaptive correction in Lagrangian puff model
International Nuclear Information System (INIS)
Lagrangian puff model is widely used in the decision support system for nuclear emergency management. The diffusion coefficient is one of the key parameters impacting puff model. An adaptive method was proposed in this paper, which could correct the diffusion coefficient in Lagrangian puff model, and it aimed to improve the accuracy of calculating the nuclide concentration distribution. This method used detected concentration data, meteorological data and source release data to estimate the actual diffusion coefficient with least square method. The diffusion coefficient adaptive correction method was evaluated by Kincaid data in MVK, and was compared with traditional Pasquill-Gifford (P-G) diffusion scheme method. The results indicate that this diffusion coefficient adaptive correction method can improve the accuracy of Lagrangian puff model. (authors)
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.
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
The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chalk......, 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 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...
Mutual diffusion coefficients of L-lysine in aqueous solutions
International Nuclear Information System (INIS)
Highlights: • Mutual diffusion coefficients of L-lysine in aqueous solutions. • Influence of the thermodynamic factors on the variation of their mutual diffusion coefficients. • Estimation of the hydrodynamic radius of L-lysine. - Abstract: Mutual diffusion coefficients, D, were determined for aqueous solutions of L-lysine at T = 298.15 K at concentrations from (0.001 to 0.100) mol · dm−3. From these experimental results, the hydrodynamic radius Rh, diffusion coefficients at infinite dilution D0, the thermodynamic factors and activity coefficients γ, by using the Hartley equation, have been estimated, permitting us to have a better understanding of the thermodynamic of these systems of L-lysine in aqueous solutions
Harris, Richard J.
Interpretation of emergent variables on the basis of structure coefficients (zero order correlations between original and emergent variables) is potentially very misleading and should be avoided in favor of interpretation on the basis of scoring coefficients. This is most apparent in multiple regression analysis and its special case, two-group…
Dynamic sagittal flexibility coefficients of the human cervical spine.
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
An analytical solution for quantum size effects on Seebeck coefficient
Karabetoglu, S.; Sisman, A.; Ozturk, Z. F.
2016-03-01
There are numerous experimental and numerical studies about quantum size effects on Seebeck coefficient. In contrast, in this study, we obtain analytical expressions for Seebeck coefficient under quantum size effects. Seebeck coefficient of a Fermi gas confined in a rectangular domain is considered. Analytical expressions, which represent the size dependency of Seebeck coefficient explicitly, are derived in terms of confinement parameters. A fundamental form of Seebeck coefficient based on infinite summations is used under relaxation time approximation. To obtain analytical results, summations are calculated using the first two terms of Poisson summation formula. It is shown that they are in good agreement with the exact results based on direct calculation of summations as long as confinement parameters are less than unity. The analytical results are also in good agreement with experimental and numerical ones in literature. Maximum relative errors of analytical expressions are less than 3% and 4% for 2D and 1D cases, respectively. Dimensional transitions of Seebeck coefficient are also examined. Furthermore, a detailed physical explanation for the oscillations in Seebeck coefficient is proposed by considering the relative standard deviation of total variance of particle number in Fermi shell.
Enlarged symmetry algebras of spin chains, loop models, and S-matrices
Energy Technology Data Exchange (ETDEWEB)
Read, N. [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520-8120 (United States)]. E-mail: nicholas.read@yale.edu; Saleur, H. [Service de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette (France) and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089 (United States)]. E-mail: hubert.saleur@cea.fr
2007-08-20
The symmetry algebras of certain families of quantum spin chains are considered in detail. The simplest examples possess m states per site (m>=2), with nearest-neighbor interactions with U(m) symmetry, under which the sites transform alternately along the chain in the fundamental m and its conjugate representation m-bar. We find that these spin chains, even with arbitrary coefficients of these interactions, have a symmetry algebra A{sub m} much larger than U(m), which implies that the energy eigenstates fall into sectors that for open chains (i.e., free boundary conditions) can be labeled by j=0,1,...,L, for the 2L-site chain such that the degeneracies of all eigenvalues in the jth sector are generically the same and increase rapidly with j. For large j, these degeneracies are much larger than those that would be expected from the U(m) symmetry alone. The enlarged symmetry algebra A{sub m}(2L) consists of operators that commute in this space of states with the Temperley-Lieb algebra that is generated by the set of nearest-neighbor interaction terms; A{sub m}(2L) is not a Yangian. There are similar results for supersymmetric chains with gl(m+n|n) symmetry of nearest-neighbor interactions, and a richer representation structure for closed chains (i.e., periodic boundary conditions). The symmetries also apply to the loop models that can be obtained from the spin chains in a spacetime or transfer matrix picture. In the loop language, the symmetries arise because the loops cannot cross. We further define tensor products of representations (for the open chains) by joining chains end to end. The fusion rules for decomposing the tensor product of representations labeled j{sub 1} and j{sub 2} take the same form as the Clebsch-Gordan series for SU(2). This and other structures turn the symmetry algebra A{sub m} into a ribbon Hopf algebra, and we show that this is 'Morita equivalent' to the quantum group U{sub q}(sl{sub 2}) for m=q+q{sup -1}. The open-chain results
Energy distribution for Coefficients of Redundant Signal Representations of Music
DEFF Research Database (Denmark)
Endelt, Line Ørtoft; la Cour-Harbo, Anders
2005-01-01
In this paper we investigate how the energy is distributed in the coefficients vector of various redundant signal representations of music signals. The representations are found using Basis Pursuit, Matching Pursuit, Alternating Projections, Best Orthogonal Basis and Method of Frames, with five...... energy in the coefficients, also the time consummation for finding the representations are considered. The distribution of energy in the coefficients of the representations found using Basis Pursuit, Matching Pursuit, Alternating Projections and Best Orthogonal Basis depends mainly on the signal, and...
Inflationary Weak Anisotropic Model with General Dissipation Coefficient
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.
Conversion coefficients and yrast state spins in 180Os
International Nuclear Information System (INIS)
Internal conversion coefficients of transitions in 180Os have been measured using a superconducting, solenoidal electron spectrometer, operated in the lens mode. The high energy resolution and efficiency allow a precise measurement of the conversion coefficients of the 528 keV yrast transition. The values obtained, αK = 0.015 (2), αL = 0.004(1) define pure E2 multipolarity. Taken with the measured γ-ray angular distribution, the conversion coefficient leads to an unambiguous assignment of 16+→14+ for the 528 keV transition. 14 refs., 5 figs., 1 tab
Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale
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.
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)
Kappa coefficient: a popular measure of rater agreement.
Tang, Wan; Hu, Jun; Zhang, Hui; Wu, Pan; He, Hua
2015-02-25
In mental health and psychosocial studies it is often necessary to report on the between-rater agreement of measures used in the study. This paper discusses the concept of agreement, highlighting its fundamental difference from correlation. Several examples demonstrate how to compute the kappa coefficient - a popular statistic for measuring agreement - both by hand and by using statistical software packages such as SAS and SPSS. Real study data are used to illustrate how to use and interpret this coefficient in clinical research and practice. The article concludes with a discussion of the limitations of the coefficient. PMID:25852260
Fresnel coefficients of a two-dimensional atomic crystal
Merano, Michele
2016-01-01
In general the experiments on the linear optical properties of a single-layer two-dimensional atomic crystal are interpreted by modeling it as a homogeneous slab with an effective thickness. Here I fit the most remarkable experiments in graphene optics by using the Fresnel coefficients, fixing both the surface susceptibility and the surface conductivity of graphene. It is shown that the Fresnel coefficients and the slab model are not equivalent. Experiments indicate that the Fresnel coefficients are able to simulate the overall experiments here analyzed, while the slab model fails to predict absorption and the phase of the reflected light.
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.
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)
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)
Ionization coefficients for argon in a micro-discharge
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.
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.
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
Drag and lift coefficients evolution of a Savonius rotor
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.
Aerodynamic force coefficients of plain bridge cables in wet conditions
DEFF Research Database (Denmark)
Matteoni, Giulia; Georgakis, Christos T.
, tests were performed for wind velocities between 2 and 31 m/s, whilst in wet conditions tests were performed for the range of wind velocities where rain rivulet formation was found possible, i.e. between 8-18 m/s. For all of the tested relative cable-wind angles in wet conditions, a reduction in the...... drag coefficient with increasing Reynolds number, accompanied by a near-zero lift coefficient, was observed. A theoretical evaluation of the aerodynamic damping assuming quasi-steady conditions reveals that changes in drag and lift coefficient are nonetheless not sufficient to generate negative...
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....
Seal assembly for materials with different coefficients of thermal expansion
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.
Transport Coefficients for Holographic Hydrodynamics at Finite Energy Scale
Ge, Xian-Hui; Fang, Li Qing; Yang, Guo-Hong
2014-01-01
We investigate the relations between black hole thermodynamics and holographic transport coefficients in this paper. The formulae for DC conductivity and diffusion coefficient are verified for electrically single-charged black holes. We examine the correctness of the proposed expressions by taking charged dilatonic and single-charged STU black holes as two concrete examples, and compute the flows of conductivity and diffusion coefficient by solving the linear order perturbation equations. We then check the consistence by evaluating the Brown-York tensor at a finite radial position. Finally, we find that the retarded Green functions for the shear modes can be expressed easily in terms of black hole thermodynamic quantities and transport coefficients.
Transport Coefficients for Holographic Hydrodynamics at Finite Energy Scale
Directory of Open Access Journals (Sweden)
Xian-Hui Ge
2014-01-01
Full Text Available We investigate the relations between black hole thermodynamics and holographic transport coefficients in this paper. The formulae for DC conductivity and diffusion coefficient are verified for electrically single-charged black holes. We examine the correctness of the proposed expressions by taking charged dilatonic and single-charged STU black holes as two concrete examples, and compute the flows of conductivity and diffusion coefficient by solving the linear order perturbation equations. We then check the consistence by evaluating the Brown-York tensor at a finite radial position. Finally, we find that the retarded Green functions for the shear modes can be expressed easily in terms of black hole thermodynamic quantities and transport coefficients.
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.
Rate coefficients for N2(+)(v) dissociative recombination
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.
Lower bound of assortativity coefficient in scale-free networks
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.
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.
Temperature dependence of the Soret coefficient of ionic colloids
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.
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.
RELICOEF: Stata module to compute Raykov's factor reliability coefficient
Mehmet Mehmetoglu
2015-01-01
relicoef computes Raykov's reliability coefficient (RRC) for factors from confirmatory factor analyses, a measure which is commonly seen as a more accurate one than that of Cronbach's alpha which is computed based on the assumption of tau-equivalent measures.
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
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...
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.
Effect of applied mechanical stress on absorption coefficient of compounds
International Nuclear Information System (INIS)
The absorption coefficient of given materials is the parameter required for the basic information. The measurement of absorption coefficient of compounds Al2O3, CaCO3, ZnO2, SmO2 and PbO has been taken at different incident photon energies 26, 59.54, 112, 1173, 1332keV. The studies involve the measurements of absorption coefficient of the self supporting samples prepared under different mechanical stress. This mechanical stress is render in terms of pressure up to 0-6 ton by using hydraulic press. Measurements shows that absorption coefficient of a material is directly proportional to applied mechanical stress on it up to some extent then become independent. Experimentally measured results are in fairly good agreement with in theoretical values obtained from WinXCOM
Isospin and density dependencies of nuclear matter symmetry energy coefficients
International Nuclear Information System (INIS)
Symmetry energy coefficients of explicitly isospin asymmetric nuclear matter at variable densities (from 0.5ρ0 up to 2ρ0) are studied as generalized screening functions. An extended stability condition for asymmetric nuclear matter is proposed. We find the possibility of obtaining stable asymmetric nuclear matter even in some cases for which the symmetric nuclear matter limit is unstable. Skyrme-type forces are extensively used in analytical expressions of the symmetry energy coefficients derived as generalized screening functions in the four channels of the particle hole interaction producing alternative behaviors at different ρ and b (respectively, the density and the asymmetry coefficient). The spin and spin-isospin coefficients, with corrections to the usual Landau Migdal parameters, indicate the possibility of occurring instabilities with common features depending on the nuclear density and n–p asymmetry. Possible relevance for high energy heavy ions collisions and astrophysical objects is discussed. (author)
Correlation coefficients and the Robertson-Schroedinger uncertainty relations
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.
Einstein's coefficients and the nature of thermal radio emission
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 .
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.
Intermittent-flow coefficients of a poppet valve
Waldron, C D
1939-01-01
Flow coefficients were determined for the inlet valve of a modern air-cooled cylinder during operation of the valve. The cylinder head with valves was mounted on a large tank that could be evacuated. Operating the valve with a rotating cam allowed air to flow through the valve into the evacuated tank. The change of pressure in the tank was a measure of the amount of air flowing though the valve in a given number of cycles. The flow coefficients were determined from the pressure across the valve, the quantity of air flowing, and the valve-lift curve. Coefficients were measured with lifts of 0.1 to 0.6 inch and speeds of 130 to 1,200 r.p.m. The results obtained with intermittent flow were compared with the results of tests made with steady flow through this cylinder head. This comparison indicated that steady-flow coefficients can be used for intermittent flow.
Determination of thermal diffusion coefficient of nanofluid: Fullerene-toluene
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.
Gamma ray attenuation coefficient measurement for neutron-absorbent materials
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.
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
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.
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.
Investigation of CNTFET Performance with Gate Control Coefficient Effect
S.A. Khan; M. Hasan; S.M. Mominuzzaman
2014-01-01
For the first time, a deep study of gate control coefficient (αG) effect on CNTFET performance has done in this research. A new, analytical CNTFET simulation along with multiple parameter approach has executed with 3D output in MATLAB and that used it to examine device performance. It is found that, drain current and transconductance increases with high gate control coefficient. On the other hand, total capacitance decreases with high αG value resulting improved charging energy. Likewise, dra...
Calculating of mutual coupling coefficients in presence cylinder
Zvezdina, Marina Yu.
2003-01-01
The problem of the selection of the singularity of the Green's function spectral representation when calculating the mutual coupling coefficients of longitudinal electrical dipoles located near the impedance circular cylinder is solved. The current distribution in the dipoles is approximated by the generalized modes. The calculation results of both addition values caused by the singularity and the mutual coupling coefficients for the case when two longitudinal dipoles are located near the imp...
Exact solutions to a nonlinear dispersive model with variable coefficients
International Nuclear Information System (INIS)
A mathematical technique based on an auxiliary differential equation and the symbolic computation system Maple is employed to investigate a prototypical and nonlinear K(n, n) equation with variable coefficients. The exact solutions to the equation are constructed analytically under various circumstances. It is shown that the variable coefficients and the exponent appearing in the equation determine the quantitative change in the physical structures of the solutions.
A Generalized Definition of the Polychoric Correlation Coefficient
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 ...
Acoustic Emotion Recognition Using Linear and Nonlinear Cepstral Coefficients
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...
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
Effect of hydrogen on the coefficient of friction of iron
Grzeskiewicz, Ronald
1988-01-01
The friction force of an Annco iron-on-Annco iron sliding system was measured in laboratory air, nitrogen, and hydrogen. The coefficient of friction for each environment was calculated and the amplitude of the "stick-slip" behavior from each environment was observed. It was found that the coefficient of friction obtained in the hydrogen environment was significantly smaller than the values obtained in laboratory air and nitrogen. Also, the amplitude of the "stick-slip" behavior ob...
Calculating rotordynamic coefficients of seals by finite-difference techniques
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.
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
Determining Absorption, Emissivity Reduction, and Local Suppression Coefficients inside Sunspots
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....
Schur Coefficients of the Integral Form Macdonald Polynomials
Yoo, Meesue
2015-01-01
In this paper, we consider the combinatorial formula for the Schur coefficients of the integral form of the Macdonald polynomials. As an attempt to prove Haglund's conjecture that $\\Biggl \\in \\mathbb{N}[q]$, we have found explicit combinatorial formulas for the Schur coefficients in one row case, two column case and certain hook shape cases [Yoo12]. A result of Egge-Loehr-Warrington [ELW] gives a combinatorial way of getting Schur expansion of symmetric functions when the expansion of the fun...
Black holes, information, and the universal coefficient theorem
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.
Estimating Crop Coefficients Using Remote Sensing-Based Vegetation Index
Directory of Open Access Journals (Sweden)
Kenneth Hubbard
2013-03-01
Full Text Available Crop coefficient (Kc-based estimation of crop evapotranspiration is one of the most commonly used methods for irrigation water management. However, uncertainties of the generalized dual crop coefficient (Kc method of the Food and Agricultural Organization of the United Nations Irrigation and Drainage Paper No. 56 can contribute to crop evapotranspiration estimates that are substantially different from actual crop evapotranspiration. Similarities between the crop coefficient curve and a satellite-derived vegetation index showed potential for modeling a crop coefficient as a function of the vegetation index. Therefore, the possibility of directly estimating the crop coefficient from satellite reflectance of a crop was investigated. The Kc data used in developing the relationship with NDVI were derived from back-calculations of the FAO-56 dual crop coefficients procedure using field data obtained during 2007 from representative US cropping systems in the High Plains from AmeriFlux sites. A simple linear regression model ( is developed to establish a general relationship between a normalized difference vegetation index (NDVI from a moderate resolution satellite data (MODIS and the crop coefficient (Kc calculated from the flux data measured for different crops and cropping practices using AmeriFlux towers. There was a strong linear correlation between the NDVI-estimated Kc and the measured Kc with an r2 of 0.91 and 0.90, while the root-mean-square error (RMSE for Kc in 2006 and 2007 were 0.16 and 0.19, respectively. The procedure for quantifying crop coefficients from NDVI data presented in this paper should be useful in other regions of the globe to understand regional irrigation water consumption.
Calculation of self-diffusion coefficients in iron
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...
Age-dependent dose coefficients for tritium in Asian populations
International Nuclear Information System (INIS)
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 10-11 Sv Bq-1 for Asian Man compared to 2.0 x 10-11 Sv Bq-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 10-11 Sv Bq-11 compared to 4.6 x 10-11 Sv Bq-1 for Reference Man. (author)
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)
Trending Time-Varying Coefficient Models With Serially Correlated Errors
Cai, Zongwu
2003-01-01
In this paper we study time-varying coefficient models with time trend function and serially correlated errors to characterize nonlinear, nonstationary and trending phenomenon in time series. Compared with the Nadaraya-Watson method, the local linear approach is developed to estimate the time trend and coefficient functions. The consistency of the proposed estimators is obtained without any specification of the error distribution and the asymptotic normality of the proposed estimators is esta...
Inference on multivariate heteroscedastic time varying random coefficient models
Giraitis, Liudas; Kapetanios, George; Yates, Tony
2015-01-01
In this paper we introduce the general setting of a multivariate time series autoregressive model with stochastic time-varying coefficients and time-varying conditional variance of the error process. This allows modeling VAR dynamics for non-stationary times series and estimation of time varying parameter processes by well-known rolling regression estimation techniques. We establish consistency, convergence rates and asymptotic normality for kernel estimators of the paths of coefficient proce...
Marginal Regression Models with Varying Coefficients for Correlated Ordinal Data
Gieger, Christian
1999-01-01
This paper discusses marginal regression models for repeated or clustered ordinal measurements in which the coefficients of explanatory variables are allowed to vary as smooth functions of other covariates. We model the marginal response probabilities and the marginal pairwise association structure by two semiparametric regressions. To estimate the fixed parameters and varying coefficients in both models we derive an algorithm that is based on penalized generalized estimating equations. This...
Null distribution of multiple correlation coefficient under mixture normal model
Hydar Ali; Nagar, Daya K.
2002-01-01
The multiple correlation coefficient is used in a large variety of statistical tests and regression problems. In this article, we derive the null distribution of the square of the sample multiple correlation coefficient, R2, when a sample is drawn from a mixture of two multivariate Gaussian populations. The moments of 1−R2 and inverse Mellin transform have been used to derive the density of R2.
Accounting for Antenna in Half-Space Fresnel Coefficient Estimation
A. D'Alterio; Solimene, R.
2012-01-01
The problem of retrieving the Fresnel reflection coefficients of a half-space medium starting from measurements collected under a reflection mode multistatic configuration is dealt with. According to our previous results, reflection coefficient estimation is cast as the inversion of linear operator. However, here, we take a step ahead towards more realistic scenarios as the role of antennas (both transmitting and receiving) is embodied in the estimation procedure. Numerical results are presen...
The power-law reaction rate coefficient for barrierless reactions
Yin, Cangtao; Du, Jiulin
2014-01-01
The power-law reaction rate coefficient for the barrierless reactions is studied if the reactions take place in systems with power-law distributions, and a generalized rate formula for the barrierless reactions in Gorin model is derived. We show that due to barrierless, different from those for bimolecular and unimolcular reactions, the power-law rate coefficient for the barrierless reactions does not have the factor of power-law distribution function and thus it is not very strongly dependen...
Transport coefficients for driven granular mixtures at low-density
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...
Optimality Conditions for Fuzzy Number Quadratic Programming with Fuzzy Coefficients
Xue-Gang Zhou; Bing-Yuan Cao; Seyed Hadi Nasseri
2014-01-01
The purpose of the present paper is to investigate optimality conditions and duality theory in fuzzy number quadratic programming (FNQP) in which the objective function is fuzzy quadratic function with fuzzy number coefficients and the constraint set is fuzzy linear functions with fuzzy number coefficients. Firstly, the equivalent quadratic programming of FNQP is presented by utilizing a linear ranking function and the dual of fuzzy number quadratic programming primal problems is introduced. ...
Simplified Calculation of the Global Thermal Insulation Coefficient
Secu, Alexandru; Romila, Claudiu
2014-01-01
According to Romanian Norm C107/1-2005, the heating energy consumption per volume is determined using the global coefficient of thermal insulation (G). The calculation requires the determination of the adjusted thermal resistance, R′, using the influence of thermal bridges on the 1D thermal resistance values. When computing G, the most time consuming stage is the determination of linear and punctual heat transfer coefficients, that requires either the use of thermal bridge catalogues (with er...
Measurement of carbon dioxide diffusion coefficient of concrete
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 ...
Coefficient strengthening : a tool for formulating mixed integer programs
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...
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
Experimental Excitation Rate Coefficients for Ne VIII Ions
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.
Experimental investigation of drag coefficients of gobi surfaces
Institute of Scientific and Technical Information of China (English)
DONG; Zhibao; (董治宝); QU; Jianjun; (屈建军); LIU; Xiaoping; (刘小平),; ZHANG; Weiming; (张伟民); &; WANG; Xunming; (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.
Attenuation Coefficient Estimation of the Healthy Human Thyroid In Vivo
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.
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.
Kinetic coefficients for the biological treatment of tannery wastewater
International Nuclear Information System (INIS)
Determination of kinetic coefficients for a particular wastewater is imperative for the rational design of biological treatment-facilities. The present study was undertaken with the objective of finding out kinetic coefficients for tannery wastewater. A bench-scale model of aerated lagoon, consisting of an aeration tank and final clarifier, was use to conduct the studies. The model was operated continuously for 96 days, by varying the detention times from 3 to 9 days. Influent for the aerated lagoon was settled tannery wastewater. Biochemical oxygen demand (BOD) of the influent and effluent and the mixed-liquor suspended solids (MLSS) of aeration tank were determined at various detention-times so as to generate data for kinetic coefficients. The kinetic coefficients k, Ks, Y and Ed were found to be 3.125 day/sup -1/, 488 mg/L, 0.64 and 0.035 day/sup -1/ respectively. Overall rate-constant of BOD, removal 'K' was also determined and was found to be 1.43 day/sup -1/. Kinetic coefficients were determined, at mean reactor-temperature of 30.2 degree C. These coefficients may be utilized for the design of biological-treatment facilities for tannery wastewater. (author)
Atmospheric Density Corrections Estimated from Fitted Drag Coefficients
McLaughlin, C. A.; Lechtenberg, T. F.; Mance, S. R.; Mehta, P.
2010-12-01
Fitted drag coefficients estimated using GEODYN, the NASA Goddard Space Flight Center Precision Orbit Determination and Geodetic Parameter Estimation Program, are used to create density corrections. The drag coefficients were estimated for Stella, Starlette and GFZ using satellite laser ranging (SLR) measurements; and for GEOSAT Follow-On (GFO) using SLR, Doppler, and altimeter crossover measurements. The data analyzed covers years ranging from 2000 to 2004 for Stella and Starlette, 2000 to 2002 and 2005 for GFO, and 1995 to 1997 for GFZ. The drag coefficient was estimated every eight hours. The drag coefficients over the course of a year show a consistent variation about the theoretical and yearly average values that primarily represents a semi-annual/seasonal error in the atmospheric density models used. The atmospheric density models examined were NRLMSISE-00 and MSIS-86. The annual structure of the major variations was consistent among all the satellites for a given year and consistent among all the years examined. The fitted drag coefficients can be converted into density corrections every eight hours along the orbit of the satellites. In addition, drag coefficients estimated more frequently can provide a higher frequency of density correction.
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
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.
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...
Generalized transport coefficients for inelastic Maxwell mixtures under shear flow.
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
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
Optimized probabilistic calibration of safety coefficients in defect severity assessments
International Nuclear Information System (INIS)
The construction codes currently used in nuclear engineering recommend analysis methods and criteria consistent with a deterministic approach. Since 1993, in the framework of work related to the RSEM codes, the EFMT Branch has launched a probabilistic approach to establish a link between the current 'deterministic' rules and failure risk assessments for the structures considered. There is an explicit link between the two approaches in the elementary strength/load case where the variables are Gaussian. This case provides the basis for the proposed methodology. In the complex case discussed in this paper, involving cracked piping with numerous non-Gaussian inputs, for a given failure mode, there is an implicit relationship between the target reliability level and the partial safety coefficients attached to each variable. The mean flaw size is the intermediate parameter used to make this link and allows flexibility in the choice of coefficients, thereby raising the question of optimized calibration. The approach is illustrated by the choice of coefficients based on the coordinates of the most probable failure point, resulting in a single set of coefficients adapted to the immediate vicinity of a given situation. In cases where the criterion must guarantee a given reliability level for a number of different operating situations, no set of coefficients can entirely guarantee the target reliability level. So, an optimized set of coefficients has to be selected, ensuring a reliability level as uniform as possible over the scope considered. This paper compares an initial coefficient proposal with a choice based on the design point method. The intermediate variable in assessing the reliability level is the mean flaw size, which would seem compatible with problems encountered under operating conditions. In addition, realistic risk assessment requires validation of the main variable distribution assumptions. We give an example of adjustment of distribution assumptions to
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...
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.
Conformal anomaly c-coefficients of superconformal 6d theories
Beccaria, Matteo; Tseytlin, Arkady A.
2016-01-01
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 i -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 super-conformal 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 i -coefficients for the "E-string" theory on multiple M5-branes at E 8 9-brane and for the theory describing M5-branes at an orbifold singularity {C}^2/Γ . Finally, we elaborate on holographic computation of subleading corrections to conformal anomaly coefficients coming from R 2 + R 3 terms in 7d effective action, revisiting, in particular, the (2,0) theory case.
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.
Local, zero-power void coefficient measurements in the ACPR
International Nuclear Information System (INIS)
Changes in reactivity may be stimulated in the ACPR by the local introduction of voids into the reactor coolant. The local void coefficients of reactivity which describe this effect are of interest from a reactor safety point-of-view, and their determination is the subject of this presentation. Bottled nitrogen gas was used to produce the voids. The gas was forced out of a small diameter tube which was positioned vertically in the core lattice with its open end below the fuel. The gas was passed through a pressure regulator, a valve, and a flowmeter to establish a steady flow condition, following which a delayed-critical (zero-power) reactor state was established. Correlation of the average volume of core void created by the nitrogen flow with the reactivity worth of the delayed-critical control-rod bank position produced the values of the zero-power void coefficients of reactivity. The void coefficients were determined at various core positions from ∼6 mm to 142 mm beyond the central irradiation space and for three different flow rates. For the range of void fractions investigated, these coefficients are negative, with values ranging between -$0.02 and -$0.12. Tabular and graphical results of the measurements are presented, and details of the coefficient determination are explained. (author)
[Biodegradation Coefficients of Typical Pollutants in the Plain Rivers Network].
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
Statistical Study of Turbulence: Spectral Functions and Correlation Coefficients
Frenkiel, Francois N.
1958-01-01
In reading the publications on turbulence of different authors, one often runs the risk of confusing the various correlation coefficients and turbulence spectra. We have made a point of defining, by appropriate concepts, the differences which exist between these functions. Besides, we introduce in the symbols a few new characteristics of turbulence. In the first chapter, we study some relations between the correlation coefficients and the different turbulence spectra. Certain relations are given by means of demonstrations which could be called intuitive rather than mathematical. In this way we demonstrate that the correlation coefficients between the simultaneous turbulent velocities at two points are identical, whether studied in Lagrange's or in Euler's systems. We then consider new spectra of turbulence, obtained by study of the simultaneous velocities along a straight line of given direction. We determine some relations between these spectra and the correlation coefficients. Examining the relation between the spectrum of the turbulence measured at a fixed point and the longitudinal-correlation curve given by G. I. Taylor, we find that this equation is exact only when the coefficient is very small.
Exact coefficients for higher dimensional operators with sixteen supersymmetries
Chen, Wei-Ming; Wen, Congkao
2015-01-01
We consider constraints on higher dimensional operators for supersymmetric effective field theories. In four dimensions with maximal supersymmetry and SU(4) R-symmetry, we demonstrate that the coefficients of abelian operators F^n with MHV helicity configurations must satisfy a recursion relation, and are completely determined by that of F^4. As the F^4 coefficient is known to be one-loop exact, this allows us to derive exact coefficients for all such operators. We also argue that the results are consistent with the SL(2,Z) duality symmetry. Breaking SU(4) to Sp(4), in anticipation for the Coulomb branch effective action, we again find an infinite class of operators whose coefficient that are determined exactly. We also consider three-dimensional N=8 as well as six-dimensional N=(2,0),(1,0) and (1,1) theories. In all cases, we demonstrate that the coefficient of dimension-six operator must be proportional to the square of that of dimension-four.
Rock shape, restitution coefficients and rockfall trajectory modelling
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.
Identification of a positive-Seebeck-coefficient exohedral fullerene.
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
Experimental determination of group flux control coefficients in metabolic networks
Energy Technology Data Exchange (ETDEWEB)
Simpson, T.W.; Shimizu, Hiroshi; Stephanopoulos, G. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering
1998-04-20
Grouping of reactions around key metabolite branch points can facilitate the study of metabolic control of complex metabolic networks. This top-down Metabolic Control Analysis is exemplified through the introduction of group control coefficients whose magnitudes provide a measure of the relative impact of each reaction group on the overall network flux, as well as on the overall network stability, following enzymatic amplification. In this article, the authors demonstrate the application of previously developed theory to the determination of group flux control coefficients. Experimental data for the changes in metabolic fluxes obtained in response to the introduction of six different environmental perturbations are used to determine the group flux control coefficients for three reaction groups formed around the phosphoenolpyruvate/pyruvate branch point. The consistency of the obtained group flux control coefficient estimates is systematically analyzed to ensure that all necessary conditions are satisfied. The magnitudes of the determined control coefficients suggest that the control of lysine production flux in Corynebacterium glutamicum cells at a growth base state resides within the lysine biosynthetic pathway that begins with the PEP/PYR carboxylation anaplorotic pathway.
Identifying Bearing Rotordynamic Coefficients using an Extended Kalman Filter
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.
Identifying Bearing Rotodynamic Coefficients Using an Extended Kalman Filter
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.
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
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)
Higher-order Cn dispersion coefficients for hydrogen
International Nuclear Information System (INIS)
The complete set of second-, third-, and fourth-order van der Waals coefficients Cn up to n=32 for the H(1s)-H(1s) dimer have been determined. They are computed by diagonalizing the nonrelativistic Hamiltonian for hydrogen to obtain a set of pseudostates that are used to evaluate the appropriate sum rules. A study of the convergence pattern for n≤16 indicates that all the Cn/16 coefficients are accurate to 13 significant digits. The relative size of the fourth-order Cn(4) to the second-order Cn(2) coefficients is seen to increase as n increases and at n=32 the fourth-order term is actually larger
Multiple element airfoils optimized for maximum lift coefficient.
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.
On the conversion coefficients for cosmic ray dosimetry
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...
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
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)
Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel
Directory of Open Access Journals (Sweden)
S. Ilaiyavel
2013-03-01
Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.
Microchip for the Measurement of Seebeck Coefficients of Single Nanowires
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.
Mutual diffusion coefficients in systems containing the nickel ion
Ribeiro, Ana C. F.; Veríssimo, Luis V. M. M.; Gomes, Joselaine C. S.; Santos, Cecilia I. A. V.; Barros, Marisa C. F.; Lobo, Victor M. M.; Sobral, Abílio J. F. N.; Esteso, Miguel A.; Leaist, Derek G.
2013-04-01
Mutual diffusion coefficients of nickel chloride in water have been measured at 293.15 K and 303.15 K and at concentrations between 0.020 mol dm-3 and 0.100 mol dm-3, using a conductimetric cell. The experimental mutual diffusion coefficients are discussed on the basis of the Onsager-Fuoss model. The equivalent conductances at infinitesimal concentration of the nickel ion in these solutions at those temperatures have been estimated using these results. In addition, from these data, we have estimated some transport and structural parameters, such as limiting diffusion coefficient, ionic conductance at infinitesimal concentration, hydrodynamic radii and activation energy, contributing this way to a better understanding of the structure of these systems and of their thermodynamic behavior in aqueous solution at different concentrations.
High Pressure Seebeck Coefficient Measurements Using Paris-Edinburgh Cell
Baker, Jason; Kumar, Ravhi; Park, Changyong; Kenney-Benson, Curtis; Velisavljevic, Nenad; Hipsec; Department Of Physics, University Of Nevada, Las Vegas Collaboration; Hpcat, Geophysical Laboratory, Carnegie Institution Of Washington Collaboration; Shock; Detonation Physics Group, Los Alamos National Laboratory Collaboration
We have developed a new type of sample cell assembly for the Paris-Edinburgh (PE) type large volume press for simultaneous x-ray diffraction, electrical resistance, and thermal measurements at high pressures. We demonstrate the feasibility of performing in situ measurements of the Seebeck coefficient over a broad range of pressure-temperature conditions by observing the well-known solid-solid and solid-melt transitions of bismuth (Bi) up to 3GPa and 450 K. We observed a gradual increase in the Seebeck coefficient which becomes positive during transition to the Bi - II phase. Also, we have performed successful Seebeck coefficient measurements on the thermoelectric material PbTe. This new capability enables us to directly correlate pressure-induced structural phase transitions to electrical and thermal properties.
Modification of Einstein A Coefficient in Dissipative Gas Medium
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.
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.
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.
Anomaly induced transport coefficients, from weak to strong coupling
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.
Estimating transport coefficients in hot and dense quark matter
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...
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
Investigations on the porous resistance coefficients for fishing net structures
DEFF Research Database (Denmark)
Chen, Hao; Christensen, Erik Damgaard
2016-01-01
a net panel from Morison type load model should be equal to the forces obtained from the porous media model. In order to account for the interaction effects in-between the twines, two coefficients were introduced, and they were calibrated by minimizing the least square error function. Extensive......The porous media model has been successfully applied to numerical simulation of current and wave interaction with traditional permeable coastal structures such as breakwaters. Recently this model was employed to simulate flow through and around fishing net structures, where the unknown porous...... resistance coefficients were adjusted by fitting the available experimental data. In the present paper, a new approach was proposed to calculate the porous resistance coefficients based on the transformation of Morison type load model. The transformation follows the principle that the total forces acting on...
Effect of raceway coating on reduction of friction coefficient
International Nuclear Information System (INIS)
The results are given of friction coefficient measurement in rubbing together wires or strands and materials considered for use in building cable race-ways. Lubricants and modifications of the inner surfaces of the pipes were used to reduce friction. The values of the coefficient of friction were studied for a wire of 5 mm in diameter and a strand of 15.5 mm in diameter rubbed against steel sheet surfaces coated with teflon, polyethylene, polyamide, and epoxy resin, against steel pipes, a metal hoses and polyethylene pipes. The effect was studied of molybdenum and steel lubricants. The results were tabulated. They showed that the friction coefficient values for wires were lower than for strands. (J.B.)
Distribution coefficients of radionuclides between Finnish soils and groundwater
International Nuclear Information System (INIS)
The distribution coefficient (Ksub(d)) has gained acceptance as a convenient means of quantifying geochemical retardation processes. The distribution coefficients of the nuclides 85Sr, 134Cs, 65Zn, 58Co and 54Mn in Finnish soils have been determined. The relationship Ksub(d) sup(Zn)>Ksub(d) sup(Cs)>Ksub(d) sup(Co)>Ksub(d) sup(Mn)>Ksub(d)sup(Sr) was found in till, sediment and clay samples. In fracture fillings the sequence was Ksub(d) sup(Zn)>Ksub(d) sup(Co)>Ksub(d) sup(Mn)>Ksub(d) sup(Cs)>Ksub(d)sup(Sr). The distribution coefficient increased with increasing cation exchange capacity of the sample. A strong correlation between Ksub(d) values and the amount of exchangeable cations in soil and water was observed. (author)
Isothermal temperature reactivity coefficient measurement in TRIGA reactor
International Nuclear Information System (INIS)
Direct measurement of an isothermal temperature reactivity coefficient at room temperatures in TRIGA Mark II research reactor at Jozef Stefan Institute in Ljubljana is presented. Temperature reactivity coefficient was measured in the temperature range between 15 oC and 25 oC. All reactivity measurements were performed at almost zero reactor power to reduce or completely eliminate nuclear heating. Slow and steady temperature decrease was controlled using the reactor tank cooling system. In this way the temperatures of fuel, of moderator and of coolant were kept in equilibrium throughout the measurements. It was found out that TRIGA reactor core loaded with standard fuel elements with stainless steel cladding has small positive isothermal temperature reactivity coefficient in this temperature range.(author)
Modeling Local Hygrothermal Interaction: Local surface transfer coefficients
DEFF Research Database (Denmark)
Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten
2009-01-01
Current models to predict heat, air and moisture (HAM) conditions in building components assume uniform boundary conditions, both for the temperature and relative humidity of the air in an indoor space as well as for the heat and moisture surface transfer coefficients. In order to obtain a reliable...... prediction of the HAM conditions in a building component, an accurate description of the indoor boundary conditions is required. This paper presents the modelling of the local indoor environmental conditions, using a (sub)zonal airflow model, focussing on the prediction of the local interior surface heat and...... moisture transfer coefficients. The research showed that the developed model gives good agreement with the local convective surface transfer coefficients predicted from CFD. The main advantage of the presented (sub)zonal airflow model is that the computational effort is relatively small, while the...
Validity of the CT to attenuation coefficient map conversion methods
International Nuclear Information System (INIS)
The most important commercialized methods of attenuation correction in SPECT are based on attenuation coefficient map from a transmission imaging method. The transmission imaging system can be the linear source of radioelement or a X-ray CT system. The image of transmission imaging system is not useful unless to replacement of the attenuation coefficient or CT number with the attenuation coefficient in SPECT energy. In this paper we essay to evaluate the validity and estimate the error of the most used method of this transformation. The final result shows that the methods which use a linear or multi-linear curve accept a error in their estimation. The value of mA is not important but the patient thickness is very important and it can introduce a error more than 10 percent in the final result
The power-law reaction rate coefficient for barrierless reactions
International Nuclear Information System (INIS)
We study the power-law reaction rate coefficient for barrierless reactions, when the reactions take place in systems with power-law distributions, and derive a generalized rate formula for the barrierless reactions in the Gorin model. We show that, unlike those for bimolecular and unimolcular reactions, due to the lack of barriers, the power-law rate coefficient for barrierless reactions does not have a power-law function, and thus is not very strongly dependent on the ν-parameter. Four barrierless reactions are taken as application examples to calculate the new rate coefficients, which with larger fitting ν-parameters can be exactly in agreement with measurements in the experimental studies. (paper)
Optimization of Power Coefficient of Wind Turbine Using Genetic Algorithm
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.
Townsend coefficients for electron scattering over dielectric surfaces
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.
Prompt temperature feedback coefficient measurement of TRR-1/M 1
International Nuclear Information System (INIS)
Prompt temperature feedback coefficient measurement of TRR-1M/1 (TRIGA MARK III) at the Office of Atomic Energy for Peace was carried out by direct measurements of heat transfer and reactor power characteristics during small power excursion experiment (reactivities less than 60 cent). An instrumented fuel element at position Bl was used to measure the temperature characteristic of fuel elements. From measured reactivities and heat transfer, prompt temperature feedback coefficient was calculated by using prompt-jump and one-delayed-neutron-group approximated diffusion equation, Newton's Law of Cooling, and linear reactivity equation. The core loading was mainly standard fuel elements. Averaged value of prompt temperature feedback coefficient obtained was-1.39 cent/degree C over the temperature range from 53 degree C to 57 degree C. The result is comparable to that obtained, by similar experiment, at the University of Arizona and about 16 percent above that reported by General Atomic Company, supplier of the reactor
Frequency-dependent seismic reflection coefficient for discriminating gas reservoirs
International Nuclear Information System (INIS)
The asymptotic equation of wave propagation in fluid-saturated porous media is available for calculating the normal reflection coefficient within a seismic frequency band. This frequency-dependent reflection coefficient is expressed in terms of a dimensionless parameter ε, which is the product of the reservoir fluid mobility (i.e. inverse viscosity), fluid density and the frequency of the signal. In this paper, we apply this expression to the Xinchang gas field, China, where reservoirs are in super-tight sands with very low permeability. We demonstrate that the variation in the reflection coefficient at a gas–water contact as a transition zone within a sand formation is observable within the seismic frequency band. Then, we conduct seismic inversion to generate attributes which first indicate the existence of fluid (either gas or water), and then discriminate a gas reservoir from a water reservoir
Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients
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.
Calculation of doppler coefficient of reactivity by WIMS code
International Nuclear Information System (INIS)
The Doppler coefficient of reactivity is an important factor in prediction of several transients in light water reactors. Some of the past studies raised the question about the 10% uncertainty that traditionally was taken in calculations of Doppler coefficient by LWR lattice code. In order to bridge the gap of lack of accurate benchmark problem to evaluate the accuracy of Doppler effect, Mosteller et al. proposed a computational benchmark problem of Doppler coefficient to evaluate the accuracy and consistency of LWR lattice physics code. In this paper we present the results obtained from WIMS-D4 lattice code and compare it with those obtained by CELL-2 lattice code part of the EPRI-PRESS reactor physics package. The results obtained from the Monte Carlo code MCNP-3A served as reference for both cases, and was taken from ref 1. (authors). 4 refs., 2 figs., 1 tab
Transport coefficients for dense hard-disk systems.
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
Dispersion coefficients of supercritical fluid in fixed beds
International Nuclear Information System (INIS)
The axial dispersion coefficient of hexachlorobenzene in supercritical carbon dioxide is investigated in a fixed -bed packed with glass beads. The on-line chromatographic pulse-response experiment is used in order to study the dynamics of a packed column under supercritical conditions. The radial dis person is assumed negligible because of the packed column geometry. To estimate the axial dispersion coefficient a pulse input of tracer/supercritical fluid (hexachlorobenzene/carbon dioxide) mixture is injected into the column and the effluent peak is analyzed using the moments of the chromatographic s curve in the Laplace d oman. The range of the operating conditions for temperature, pressure and flow rate of supercritical fluid are 25-50 deg C, 1200-4000 psia and 120-160 ml/hr, respectively. The experimental data indicate that the axial dispersion coefficient is a function of temperature, pressure and flow rate. The axial dapperness coefficient decrease with increasing temperature and increase with increasing pressure. This trend may be due to the increase of the density and viscosity of the supercritical carbon dioxide. Furthermore, the axial dispersion coefficient increase with increasing interstitial velocity. These results suggest that the contribution by convection is more important than molecular diffusion under supercritical operations. In order to investigate the authenticity of the dynamic model as well as the extent of accuracy of the moment analysis which is used for parameter estimation, the experimental response peak is compared with the dimensionless theoretical (numerical solution) curve. The small deviation between the two curves is well within the range of experimental error of axial dispersion coefficient measurements
Measuring the Soret coefficient of nanoparticles in a dilute suspension.
Zhao, Chao; Fu, Jinxin; Oztekin, Alparslan; Cheng, Xuanhong
2014-10-01
Thermophoresis is an efficient process for the manipulation of molecules and nanoparticles due to the strong force it generates on the nanoscale. Thermophoresis is characterized by the Soret coefficient. Conventionally, the Soret coefficient of nanosized species is obtained by fitting the concentration profile under a temperature gradient at the steady state to a continuous phase model. However, when the number density of the target is ultralow and the dispersed species cannot be treated as a continuous phase, the bulk concentration fluctuates spatially, preventing extraction of temperature-gradient induced concentration profile. The present work demonstrates a strategy to tackle this problem by superimposing snapshots of nanoparticle distribution. The resulting image is suitable for the extraction of the Soret coefficient through the conventional data fitting method. The strategy is first tested through a discrete phase model that illustrates the spatial fluctuation of the nanoparticle concentration in a dilute suspension in response to the temperature gradient. By superimposing snapshots of the stochastic distribution, a thermophoretic depletion profile with low standard error is constructed, indicative of the Soret coefficient. Next, confocal analysis of nanoparticle distribution in response to a temperature gradient is performed using polystyrene nanobeads down to 1e-5% (v/v). The experimental results also reveal that superimposing enhances the accuracy of extracted Soret coefficient. The critical particle number density in the superimposed image for predicting the Soret coefficient is hypothesized to depend on the spatial resolution of the image. This study also demonstrates that the discrete phase model is an effective tool to study particle migration under thermophoresis in the liquid phase. PMID:25221433
Using VPHOT and PTGP to Generate Transformation Coefficients (Abstract)
Menzies, K.; Myers, G.
2015-06-01
(Abstract only) The AAVSO web site hosts two useful tools, VPHOT and PTGP, to help develop your transformation coefficients. They can be used together to simplify a tedious process involving standard comparison star selection, image reduction and spreadsheet analysis. The process necessary to generate Transformation Coefficients involves: (1) measurement of instrumental magnitudes of Standard Comparison Stars, (2) measurement of instrumental magnitudes for a set of images and filters (UBVRI), and (3) downloading of comparison star magnitude files in a standard format. The subsequent process involves: (4) importing the set of standard comparison star magnitude files into PTGP, and (5) the automatic calculation of transformation coefficients and transformation plots. During testing in vphot and PTGP, simple steps and alternatives have been identified to generate accurate transform coefficients. The first VPHOT step is the obvious need to upload multiple images in multiple standard filters to VPHOT. The second step is to open each image, overlay all standard comparison stars (currently M67 or NGC 7790), view the photometry table, and download the comparison star magnitude data files. Two alternatives involve either the use of individual image files (for example, 4B, 4V, 4R; 4I) or the stacking of all images for each filter (for example, 1B, 1V, 1R; 1I). The latter improves the SNR. In PTGP after the selection of telescope, standard fields, and data reduction software, one selects all comp star magnitude files. The “Calculate Transform Set” button calculates the applicable filter magnitude and color index coefficients. Testing of this process included an evaluation of the impact of several alternatives including: (1) choice of individual filter images or stacked filter images, (2) choice of all standard comparison stars or a selected subset of standard comparison stars, and (3) choice of a minimum SNR. Each of these alternatives affects the transformation
Scattering and absorption coefficients of silica-doped alumina aerogels.
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
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.
Generalized heat kernel coefficients for a new asymptotic expansion
International Nuclear Information System (INIS)
The method which allows for asymptotic expansion of the one-loop effective action W = lndetA is formulated. The positively defined elliptic operator A = U + M2 depends on the external classical fields taking values in the Lie algebra of the internal symmetry group G. Unlike the standard method of Schwinger - DeWitt, the more general case with the nongenerate mass matrix M = diag(m1, m2, ...) is considered. The first coefficients of the new asymptotic series are calculated and their relationship with the Seeley - DeWitt coefficients is clarified
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.
Overall mass-transfer coefficients in non-linear chromatography
DEFF Research Database (Denmark)
Mollerup, Jørgen; Hansen, Ernst
1998-01-01
In case of mass transfer where concentration differences in both phases must be taken into account, one may define an over-all mass-transfer coefficient basd on the apparent over-all concentration difference. If the equilibrium relationship is linear, i.e. in cases where a Henry´s law relationshi...... shown in this paper. In this case one has to discard the use of over-all mass-transfer coefficients and calculate the rate of mass transfer from the two film theory using the appropriate non-linear relationship to calculate the equilibrium ratio at the interface between the two films....
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.
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)
Nitrogen ion implantation effect on friction coefficient of tool steel
International Nuclear Information System (INIS)
Effect of nitrogen molecular ion implantation into KhVSG steel on the friction coefficient in the air and vacuum is investigated. Irradiation is carried out by the N2+ beam with energy 120 keV and flux density 5 μ/cm2 at room temperature in vacuum 5x10-4Pa. The integral dose of irradiation is 1017 particle/cm2. Nitrogen ion implantation is shown to provide the formation of the modified layer changing friction properties of steel. The friction coefficient can either increase or decrease depending on implantation and test conditions. 4 refs.; 2 figs