Green functions in Bianci-type spaces

International Nuclear Information System (INIS)

Bukhbinder, I.L.; Kirillova, E.N.

1988-01-01

The theory of free scalar field with conformal connection in distorted space - time with Bianci 1 type metrics is considered. The presentation of the Green functions G-tilde approximately in in in the form of integral from the Schwinger - De Witt kernel over the contour in the plane of complex values of eigentime is obtained. The way, in which the transfer from the Green function in space with Euclidean signature to the Green functions in space with Minkowski signature and vice versa is realized, has been shown

Green close-quote s function method with energy-independent vertex functions

International Nuclear Information System (INIS)

Tsay Tzeng, S.Y.; Kuo, T.T.; Tzeng, Y.; Geyer, H.B.; Navratil, P.

1996-01-01

In conventional Green close-quote s function methods the vertex function Γ is generally energy dependent. However, a model-space Green close-quote s function method where the vertex function is manifestly energy independent can be formulated using energy-independent effective interaction theories based on folded diagrams and/or similarity transformations. This is discussed in general and then illustrated for a 1p1h model-space Green close-quote s function applied to a solvable Lipkin many-fermion model. The poles of the conventional Green close-quote s function are obtained by solving a self-consistent Dyson equation and model space calculations may lead to unphysical poles. For the energy-independent model-space Green close-quote s function only the physical poles of the model problem are reproduced and are in satisfactory agreement with the exact excitation energies. copyright 1996 The American Physical Society

Functional equations and Green's functions for augmented scalar fields

International Nuclear Information System (INIS)

Klauder, J.R.

1977-01-01

Certain noncanonical self-coupled scalar quantum field theories, previously formulated by means of functional integration, are herein recast into the form of functional differential equations for the Green's functional. From these expressions the set of coupled equations relating the Green's functions is obtained. The new equations are compared with those of the conventional formulation, and are proposed as alternatives, especially for nonrenormalizable models when the conventional equations fail

Green's functions of solitons in heat bath

International Nuclear Information System (INIS)

Smilga, A.V.

1989-01-01

Soliton Green's functions at nonzero temperature are studied. Considering various model example it is shown that the Green's function pole position does not coincide generally speaking with free energy of a soliton. The Froelich polaron and the t'Hooft-Polyakov monopole the Green's function for which is in general a poorly defined concept as it involves an infinite imaginary part connected to the infinite total cross section of monopole scattering by electric charge are discussed. The pole position of the Green's function of the collective sphaleron excitation in the Glashow-Weinberg-Salem model does not as well coincide with the sphaleron free energy. 24 refs.; 9 figs

Many-Body Green Function of Degenerate Systems

International Nuclear Information System (INIS)

Brouder, Christian; Panati, Gianluca; Stoltz, Gabriel

2009-01-01

A rigorous nonperturbative adiabatic approximation of the evolution operator in the many-body physics of degenerate systems is derived. This approximation is used to solve the long-standing problem of the choice of the initial states of H 0 leading to eigenstates of H 0 +V for degenerate systems. These initial states are eigenstates of P 0 VP 0 , where P 0 is the projection onto a degenerate eigenspace of H 0 . This result is used to give the proper definition of the Green function, the statistical Green function and the nonequilibrium Green function of degenerate systems. The convergence of these Green functions is established.

Semiclassical initial value approximation for Green's function.

Science.gov (United States)

Kay, Kenneth G

2010-06-28

A semiclassical initial value approximation is obtained for the energy-dependent Green's function. For a system with f degrees of freedom the Green's function expression has the form of a (2f-1)-dimensional integral over points on the energy surface and an integral over time along classical trajectories initiated from these points. This approximation is derived by requiring an integral ansatz for Green's function to reduce to Gutzwiller's semiclassical formula when the integrations are performed by the stationary phase method. A simpler approximation is also derived involving only an (f-1)-dimensional integral over momentum variables on a Poincare surface and an integral over time. The relationship between the present expressions and an earlier initial value approximation for energy eigenfunctions is explored. Numerical tests for two-dimensional systems indicate that good accuracy can be obtained from the initial value Green's function for calculations of autocorrelation spectra and time-independent wave functions. The relative advantages of initial value approximations for the energy-dependent Green's function and the time-dependent propagator are discussed.

Green functions in an external electric field

International Nuclear Information System (INIS)

Gavrilov, S.P.; Gitman, D.M.; Shvartsman, Sh.M.

1979-01-01

In the framework of scalar quantum electrodynamics, when vacuum is unstable as to the birth of electron-positron couples, calculated have been Green functions for the case of stable homogeneous electric field. By summing corresponding solutions of the Klein-Gordon equation of the Green function are obtained in the form of contour integrals according to the proper time. Operation representations of all the calculated Green functions in the mentioned field are presented

Green's functions in quantum physics. 3. ed.

International Nuclear Information System (INIS)

Economou, E.N.

2006-01-01

The new edition of a standard reference will be of interest to advanced students wishing to become familiar with the method of Green's functions for obtaining simple and general solutions to basic problems in quantum physics. The main part is devoted to the simplest kind of Green's functions, namely the solutions of linear differential equations with a -function source. It is shown that these familiar Green's functions are a powerful tool for obtaining relatively simple and general solutions of basic problems such as scattering and bound level information. The bound-level treatment gives a clear physical understanding of ''difficult'' questions such as superconductivity, the Kondo effect, and, to a lesser degree, disorder-induced localization. The more advanced subject of many-body Green's functions is presented in the last part of the book. This third edition is 50% longer than the previous and offers end-of-chapter problems and solutions (40% are solved) and additional appendices to help it is to serve as an effective self-tutorial and self-sufficient reference. Throughout, it demonstrates the powerful and unifying formalism of Green's functions across many applications, including transport properties, carbon nanotubes, and photonics and photonic crystals. (orig.)

A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval

Science.gov (United States)

Wapenaar, Kees; Thorbecke, Jan; van der Neut, Joost

2016-04-01

Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's function of the wave equation without a singularity on the right-hand side) is represented by a closed boundary integral. In practical applications, sources and/or receivers are usually present only on an open surface, which implies that a significant part of the closed boundary integral is by necessity ignored. Here we derive a homogeneous Green's function representation for the common situation that sources and/or receivers are present on an open surface only. We modify the integrand in such a way that it vanishes on the part of the boundary where no sources and receivers are present. As a consequence, the remaining integral along the open surface is an accurate single-sided representation of the homogeneous Green's function. This single-sided representation accounts for all orders of multiple scattering. The new representation significantly improves the aforementioned wavefield imaging applications, particularly in situations where the first-order scattering approximation breaks down.

Multiconfigurational Green's function approaches in quantum chemistry

International Nuclear Information System (INIS)

Yeager, D.L.

1984-01-01

The author discusses multiconfigurational Green's function techniques and generalizations. In particular he is interested in developing and applying these techniques for isolated atoms and small molecules. Furthermore, he develops formalisms that are fairly clear, accurate, and capable of being applied to open-shell and highly-correlated systems as well as to closed-shell systems with little electronic correlation. The two kinds of Green's functions that this article discusses are the single-particle Green's function and the retarded two-time Green's function in the energy representation. The poles of the former give the ionization potentials and electron affinities while the poles of the latter give the excitation energies. The multiconfigurational approximations are known as the multiconfigurational electron propagator (MCEP) and the multiconfigurational time-dependent Hartree-Fock (MCTDHF) (also known as the multiconfigurational random phase approximation (MCRPA) or the multiconfigurational linear response), respectively. 44 references

On toroidal Green close-quote s functions

International Nuclear Information System (INIS)

Bates, J.W.

1997-01-01

Green close-quote s functions are valuable analytical tools for solving a myriad of boundary-value problems in mathematical physics. Here, Green close-quote s functions of the Laplacian and biharmonic operators are derived for a three-dimensional toroidal domain. In some sense, the former result may be regarded as open-quotes standard,close quotes but the latter is most certainly not. It is shown that both functions can be constructed to have zero value on a specified toroidal surface with a circular cross section. Additionally, the Green close-quote s function of the biharmonic operator may be chosen to have the property that its normal derivative also vanishes there. A open-quotes torsionalclose quotes Green close-quote s function is derived for each operator which is useful in solving some boundary-value problems involving axisymmetric vector equations. Using this approach, the magnetic vector potential of a wire loop is computed as a simple example. copyright 1997 American Institute of Physics

The Green's function method for critical heterogeneous slabs

International Nuclear Information System (INIS)

Kornreich, D.E.

1996-01-01

Recently, the Green's Function Method (GFM) has been employed to obtain benchmark-quality results for nuclear engineering and radiative transfer calculations. This was possible because of fast and accurate calculations of the Green's function and the associated Fourier and Laplace transform inversions. Calculations have been provided in one-dimensional slab geometries for both homogeneous and heterogeneous media. A heterogeneous medium is analyzed as a series of homogeneous slabs, and Placzek's lemma is used to extend each slab to infinity. This allows use of the infinite medium Green's function (the anisotropic plane source in an infinite homogeneous medium) in the solution. To this point, a drawback of the GFM has been the limitation to media with c 1; however, mathematical solutions exist which result in oscillating Green's functions. Such calculations are briefly discussing. The limitation to media with c < 1 has been relaxed so that the Green's function may also be calculated for media with c ≥ 1. Thus, materials that contain fissionable isotopes may be modeled

Green's function and boundary elements of multifield materials

CERN Document Server

Qin, Qing-Hua

2007-01-01

Green's Function and Boundary Elements of Multifield Materials contains a comprehensive treatment of multifield materials under coupled thermal, magnetic, electric, and mechanical loads. Its easy-to-understand text clarifies some of the most advanced techniques for deriving Green's function and the related boundary element formulation of magnetoelectroelastic materials: Radon transform, potential function approach, Fourier transform. Our hope in preparing this book is to attract interested readers and researchers to a new field that continues to provide fascinating and technologically important challenges. You will benefit from the authors' thorough coverage of general principles for each topic, followed by detailed mathematical derivation and worked examples as well as tables and figures where appropriate. In-depth explanations of the concept of Green's function Coupled thermo-magneto-electro-elastic analysis Detailed mathematical derivation for Green's functions.

Worldline Green functions for multiloop diagrams

International Nuclear Information System (INIS)

Schmidt, M.G.; Heidelberg Univ.; Schubert, C.

1994-03-01

We propose a multiloop generalization of the Bern-Kosower formalism, based on Strassler's approach of evaluating worldline path integrals by worldline Green functions. Those Green functions are explicitly constructed for the basic two-loop graph, and for a loop with an arbitrary number of propagator insertions. For scalar and abelian gauge theories, the resulting integral representations allow to combine whole classes of Feynman diagrams into compact expressions. (orig.)

Green's function for a generalized two-dimensional fluid.

Science.gov (United States)

Iwayama, Takahiro; Watanabe, Takeshi

2010-09-01

A Green's function for a generalized two-dimensional (2D) fluid in an unbounded domain (the so-called α turbulence system) is discussed. The generalized 2D fluid is characterized by a relationship between an advected quantity q and the stream function ψ : namely, q=-(-Δ){α/2}ψ . Here, α is a real number and q is referred to as the vorticity. In this study, the Green's function refers to the stream function produced by a delta-functional distribution of q , i.e., a point vortex with unit strength. The Green's function has the form G{(α)}(r)∝r{α-2} , except when α is an even number, where r is the distance from the point vortex. This functional form is known as the Riesz potential. When α is a positive even number, the logarithmic correction to the Riesz potential has the form G(r){(α)}∝r{α-2} ln r . In contrast, when α is a negative even number, G{(α)} is given by the higher-order Laplacian of the delta function. The transition of the small-scale behavior of q at α=2 , a well-known property of forced and dissipative α turbulence, is explained in terms of the Green's function. Moreover, the azimuthal velocity around the point vortex is derived from the Green's function. The functional form of the azimuthal velocity indicates that physically realizable systems for the generalized 2D fluid exist only when α≤3 . The Green's function and physically realizable systems for an anisotropic generalized 2D fluid are presented as an application of the present study.

Single-particle properties from Kohn-Sham Green's functions

International Nuclear Information System (INIS)

Bhattacharyya, Anirban; Furnstahl, R.J.

2005-01-01

An effective action approach to Kohn-Sham density functional theory is used to illustrate how the exact Green's function can be calculated in terms of the Kohn-Sham Green's function. An example based on Skyrme energy functionals shows that single-particle Kohn-Sham spectra can be improved by adding sources used to construct the energy functional

Thermodynamic Green functions in theory of superconductivity

Directory of Open Access Journals (Sweden)

N.M.Plakida

2006-01-01

Full Text Available A general theory of superconductivity is formulated within the thermodynamic Green function method for various types of pairing mediated by phonons, spin fluctuations, and strong Coulomb correlations in the Hubbard and t-J models. A rigorous Dyson equation for matrix Green functions is derived in terms of a self-energy as a many-particle Green function. By applying the noncrossing approximation for the self-energy, a closed self-consistent system of equations is obtained, similar to the conventional Eliashberg equations. A brief discussion of superconductivity mediated by kinematic interaction with an estimation of a superconducting transition temperature in the Hubbard model is given.

A practical guide to averaging functions

CERN Document Server

Beliakov, Gleb; Calvo Sánchez, Tomasa

2016-01-01

This book offers an easy-to-use and practice-oriented reference guide to mathematical averages. It presents different ways of aggregating input values given on a numerical scale, and of choosing and/or constructing aggregating functions for specific applications. Building on a previous monograph by Beliakov et al. published by Springer in 2007, it outlines new aggregation methods developed in the interim, with a special focus on the topic of averaging aggregation functions. It examines recent advances in the field, such as aggregation on lattices, penalty-based aggregation and weakly monotone averaging, and extends many of the already existing methods, such as: ordered weighted averaging (OWA), fuzzy integrals and mixture functions. A substantial mathematical background is not called for, as all the relevant mathematical notions are explained here and reported on together with a wealth of graphical illustrations of distinct families of aggregation functions. The authors mainly focus on practical applications ...

Green function of the model two-centre quantum-mechanical problem

International Nuclear Information System (INIS)

Khoma, M.V.; Lazur, V.Yu.

2002-01-01

The expansions of a Green function for the Simmons molecular potential (SMP) in terms of spheroidal function are built. The solutions of degenerate hypergeometric equation are used as basis function system while expanding regular and irregular model spheroidal functions into series. Rather simple three-terms recurrence relations are obtained for the coefficients of these expansions. Much attentions is given to different asymptotic representation as well as Sturmian expansions of the Green function of the two-centre SMP wave functions. In all cases considered the Green function is reduced to the form similar to the Hostler's representation of the Coulomb Green function

Green function simulation of Hamiltonian lattice models with stochastic reconfiguration

International Nuclear Information System (INIS)

Beccaria, M.

2000-01-01

We apply a recently proposed Green function Monte Carlo procedure to the study of Hamiltonian lattice gauge theories. This class of algorithms computes quantum vacuum expectation values by averaging over a set of suitable weighted random walkers. By means of a procedure called stochastic reconfiguration the long standing problem of keeping fixed the walker population without a priori knowledge of the ground state is completely solved. In the U(1) 2 model, which we choose as our theoretical laboratory, we evaluate the mean plaquette and the vacuum energy per plaquette. We find good agreement with previous works using model-dependent guiding functions for the random walkers. (orig.)

Green functions for an electron in an external electromagnetic field

International Nuclear Information System (INIS)

Khokhlov, I.A.

1982-01-01

New representations permitting to considerably simplify their calculation have been obtained for the Green functions of electron. These representations are based on an idea, used in the quantum electrodynamics formulation in variables of a zero plane, of writing down the Dirac field operator psi through its part psisub((-)). It is shown that T product of psi and psi + operators can be expressed through T product of their parts psisub((-)) and psisub((-))sup(+). At that, if the anticommutator of the operators psisub((-)) and psisub((-))sup(+) satisfies the initial condition, the operations of the chronological ordering of the operator product psi(-) and psisub((-))sup(+) with respect to variable x 0 and variable u 0 playing a part of time in the formulation of the zero plane (Pu 0 product) coincide. In correspondence with this fact all the Green functions of electron can be expressed depending on the convenience of concrete calculations through vacuum averages of either from T product or from Pu 0 product of psisub((-)) and psisub((-))sup(+) operators only [ru

Functional-derivative study of the Hubbard model. III. Fully renormalized Green's function

International Nuclear Information System (INIS)

Arai, T.; Cohen, M.H.

1980-01-01

The functional-derivative method of calculating the Green's function developed earlier for the Hubbard model is generalized and used to obtain a fully renormalized solution. Higher-order functional derivatives operating on the basic Green's functions, G and GAMMA, are all evaluated explicitly, thus making the solution applicable to the narrow-band region as well as the wide-band region. Correction terms Phi generated from functional derivatives of equal-time Green's functions of the type delta/sup n/ /deltaepsilon/sup n/, etc., with n > or = 2. It is found that the Phi's are, in fact, renormalization factors involved in the self-energy Σ and that the structure of the Phi's resembles that of Σ and contains the same renormalization factors Phi. The renormalization factors Phi are shown to satisfy a set of equations and can be evaluated self-consistently. In the presence of the Phi's, all difficulties found in the previous results (papers I and II) are removed, and the energy spectrum ω can now be evaluated for all occupations n. The Schwinger relation is the only basic relation used in generating this fully self-consistent Green's function, and the Baym-Kadanoff continuity condition is automatically satisfied

Sourcewise represented green's function of the circular waveguide

International Nuclear Information System (INIS)

Prijmenko, S.D.; Bondarenko, L.A.

2007-01-01

Singular part of the Green's function of unbounded space is singled out in explicit form and contains all singularities, including a delta-shaped singularity. The problem of construction of Green's function for a field is solved, as a problem for diffraction of potential and rotational components electric field intensity of a point current source on the circular waveguide walls. The singling out of the electric field intensity singularity in an explicit form about a source enables to develop an effective algorithm of Green's function calculation at any distance between the source point and observation point in a circular waveguide

A Green function of neutron transport equation

International Nuclear Information System (INIS)

Simovic, R.

1993-01-01

In this paper the angularly dependent Green function of the neutron transport equation is derived analytically and approximately. By applying the analytical FDPN approximation up to eighth order, numerical values of the Green functions are obtained with the accuracy of six significant figures in the whole range of parameter c, angle cosine μ and distances x up to the ten optical lengths from the neutron source. (author)

Temperature-dependent striped antiferromagnetism of LaFeAsO in a Green's function approach

International Nuclear Information System (INIS)

Liu Guibin; Liu Banggui

2009-01-01

We use a Green's function method to study the temperature-dependent average moment and magnetic phase-transition temperature of the striped antiferromagnetism of LaFeAsO, and other similar compounds, as the parents of FeAs-based superconductors. We consider the nearest and the next-nearest couplings in the FeAs layer, and the nearest coupling for inter-layer spin interaction. The dependence of the transition temperature T N and the zero-temperature average spin on the interaction constants is investigated. We obtain an analytical expression for T N and determine our temperature-dependent average spin from zero temperature to T N in terms of unified self-consistent equations. For LaFeAsO, we obtain a reasonable estimation of the coupling interactions with the experimental transition temperature T N = 138 K. Our results also show that a non-zero antiferromagnetic (AFM) inter-layer coupling is essential for the existence of a non-zero T N , and the many-body AFM fluctuations reduce substantially the low-temperature magnetic moment per Fe towards the experimental value. Our Green's function approach can be used for other FeAs-based parent compounds and these results should be useful to understand the physical properties of FeAs-based superconductors.

Green tea effects on cognition, mood and human brain function: A systematic review.

Science.gov (United States)

Mancini, Edele; Beglinger, Christoph; Drewe, Jürgen; Zanchi, Davide; Lang, Undine E; Borgwardt, Stefan

2017-10-15

Green tea (Camellia sinensis) is a beverage consumed for thousands of years. Numerous claims about the benefits of its consumption were stated and investigated. As green tea is experiencing a surge in popularity in Western culture and as millions of people all over the world drink it every day, it is relevant to understand its effects on the human brain. To assess the current state of knowledge in the literature regarding the effects of green tea or green tea extracts, l-theanine and epigallocatechin gallate both components of green tea-on general neuropsychology, on the sub-category cognition and on brain functions in humans. We systematically searched on PubMed database and selected studies by predefined eligibility criteria. We then assessed their quality and extracted data. We structured our effort according to the PRISMA statement. We reviewed and assessed 21 studies, 4 of which were randomised controlled trials, 12 cross-over studies (both assessed with an adapted version of the DELPHI-list), 4 were cross-sectional studies and one was a cohort study (both assessed with an adapted version of the Newcastle-Ottawa assessment scale). The average study quality as appraised by means of the DELPHI-list was good (8.06/9); the studies evaluated with the Newcastle-Ottawa-scale were also good (6.7/9). The reviewed studies presented evidence that green tea influences psychopathological symptoms (e.g. reduction of anxiety), cognition (e.g. benefits in memory and attention) and brain function (e.g. activation of working memory seen in functional MRI). The effects of green tea cannot be attributed to a single constituent of the beverage. This is exemplified in the finding that beneficial green tea effects on cognition are observed under the combined influence of both caffeine and l-theanine, whereas separate administration of either substance was found to have a lesser impact. Copyright © 2017. Published by Elsevier GmbH.

Dirac Coulomb Green's function and its application to relativistic Rayleigh scattering

International Nuclear Information System (INIS)

Wong, M.K.F.; Yeh, E.H.Y.

1985-01-01

The Dirac Coulomb Green's function is obtained in both coordinate and momentum space. The Green's function in coordinate space is obtained by the eigenfunction expansion method in terms of the wave functions obtained by Wong and Yeh. The result is simpler than those obtained previously by other authors, in that the radial part for each component contains one term only instead of four terms. Our Green's function reduces to the Schroedinger Green's function upon some simple conditions, chiefly by neglecting the spin and replacing lambda by l. The Green's function in momentum space is obtained as the Fourier transform of the coordinate space Green's function, and is expressed in terms of basically three types of functions: (1) F/sub A/ (α; β 1 β 2 β 3 ; γ 1 γ 2 γ 3 ; z 1 z 2 z 3 ), (2) the hypergeometric function, and (3) spherical harmonics. The matrix element for Rayleigh scattering, or elastic Compton scattering, from relativistically bound electrons is then obtained in analytically closed form. The matrix element is written basically in terms of the coordinate space Dirac Coulomb Green's function. The technique used in the evaluation of the matrix element is based on the calculation of the momentum space Dirac Coulomb Green's function. Finally the relativistic result is compared with the nonrelativistic result

Green's function for anti--de Sitter space gravity

International Nuclear Information System (INIS)

Kleppe, G.

1994-01-01

We solve for the retarded Green's function for linearized gravity in a background with a negative cosmological constant, anti--de Sitter space. In this background, it is possible for a signal to reach spatial infinity in a finite time. Therefore the form of the Green's function depends on a choice of boundary condition at spatial infinity. We take as our condition that a signal which reaches infinity should be lost, not reflected back. We calculate the Green's function associated with this condition, and show that it reproduces the correct classical solution for a point mass at the origin, the anti--de Sitter--Schwarzschild solution

Green's function matching method for adjoining regions having different masses

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J

2006-01-01

We present a primer on the method of Green's function matching for the determination of the global Schroedinger Green's function for all space subject to joining conditions at an interface between two (or more) separate parts of the region having different masses. The object of this technique is to determine the full space Schroedinger Green's function in terms of the individual Green's functions of the constituent parts taken as if they were themselves extended to all space. This analytical method has had successful applications in the theory of surface states, and remains of interest for nanostructures

Unified double- and single-sided homogeneous Green's function representations

Science.gov (United States)

Wapenaar, Kees; van der Neut, Joost; Slob, Evert

2016-06-01

In wave theory, the homogeneous Green's function consists of the impulse response to a point source, minus its time-reversal. It can be represented by a closed boundary integral. In many practical situations, the closed boundary integral needs to be approximated by an open boundary integral because the medium of interest is often accessible from one side only. The inherent approximations are acceptable as long as the effects of multiple scattering are negligible. However, in case of strongly inhomogeneous media, the effects of multiple scattering can be severe. We derive double- and single-sided homogeneous Green's function representations. The single-sided representation applies to situations where the medium can be accessed from one side only. It correctly handles multiple scattering. It employs a focusing function instead of the backward propagating Green's function in the classical (double-sided) representation. When reflection measurements are available at the accessible boundary of the medium, the focusing function can be retrieved from these measurements. Throughout the paper, we use a unified notation which applies to acoustic, quantum-mechanical, electromagnetic and elastodynamic waves. We foresee many interesting applications of the unified single-sided homogeneous Green's function representation in holographic imaging and inverse scattering, time-reversed wave field propagation and interferometric Green's function retrieval.

A spectral measurement method for determining white OLED average junction temperatures

Science.gov (United States)

Zhu, Yiting; Narendran, Nadarajah

2016-09-01

The objective of this study was to investigate an indirect method of measuring the average junction temperature of a white organic light-emitting diode (OLED) based on temperature sensitivity differences in the radiant power emitted by individual emitter materials (i.e., "blue," "green," and "red"). The measured spectral power distributions (SPDs) of the white OLED as a function of temperature showed amplitude decrease as a function of temperature in the different spectral bands, red, green, and blue. Analyzed data showed a good linear correlation between the integrated radiance for each spectral band and the OLED panel temperature, measured at a reference point on the back surface of the panel. The integrated radiance ratio of the spectral band green compared to red, (G/R), correlates linearly with panel temperature. Assuming that the panel reference point temperature is proportional to the average junction temperature of the OLED panel, the G/R ratio can be used for estimating the average junction temperature of an OLED panel.

Superoperator nonequilibrium Green's function theory of many-body systems; applications to charge transfer and transport in open junctions

International Nuclear Information System (INIS)

Harbola, U.; Mukamel, S.

2008-01-01

Nonequilibrium Green's functions provide a powerful tool for computing the dynamical response and particle exchange statistics of coupled quantum systems. We formulate the theory in terms of the density matrix in Liouville space and introduce superoperator algebra that greatly simplifies the derivation and the physical interpretation of all quantities. Expressions for various observables are derived directly in real time in terms of superoperator nonequilibrium Green's functions (SNGF), rather than the artificial time-loop required in Schwinger's Hilbert-space formulation. Applications for computing interaction energies, charge densities, average currents, current induced fluorescence, electroluminescence and current fluctuation (electron counting) statistics are discussed

Plant species and functional group combinations affect green roof ecosystem functions.

Science.gov (United States)

Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa

2010-03-12

Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green

The green's functions of superconductivity- A review | Imo | Global ...

African Journals Online (AJOL)

We present some basic Green's functions of superconductivity, making emphasis on their geneology and analytic properties. From calculations, we note that the temperature dependence of the Green's functions for fermionic (and bosonic) systems limits and defines the extent of their applications and results. Furthermore ...

Nonlocal surface plasmons by Poisson Green's function matching

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J

2006-01-01

The Poisson Green's function for all space is derived for the case in which an interface divides space into two separate semi-infinite media, using the Green's function matching method. Each of the separate semi-infinite constituent parts has its own dynamic, nonlocal polarizability, which is taken to be unaffected by the presence of the interface and is represented by the corresponding bulk response property. While this eliminates Friedel oscillatory phenomenology near the interface with p ∼ 2p F , it is nevertheless quite reasonable and useful for a broad range of lower (nonvanishing) wavenumbers, p F . The resulting full-space Poisson Green's function is dynamic, nonlocal and spatially inhomogeneous, and its frequency pole yields the surface plasmon dispersion relation, replete with dynamic and nonlocal features. It also accommodates an ambient magnetic field

Non-perturbative Green functions in quantum gauge theories

International Nuclear Information System (INIS)

Shabanov, S.V.

1991-01-01

Non-perturbative Green functions for gauge invariant variables are considered. The Green functions are found to be modified as compared with the usual ones in a definite gauge because of a physical configuration space (PCS) reduction. In the Yang-Mills theory with fermions this phenomenon follows from the Singer theorem about the absence of a global gauge condition for the fields tensing to zero at spatial infinity. 20 refs

Harmonic supergraphs. Green functions

International Nuclear Information System (INIS)

Galperin, A.; Ivanov, E.; Gievetsky, V.; Sokatchev, E.

1985-01-01

The quantization procedure in the harmonic superspace approach is worked out. Harmonic distributions are introduced and are used to construct the analytic superspace delta-functions and the Green functions for the hypermultiplet and the N=2 Yang-Mills superfields. The gauge fixing is described and the relevant Faddeev-Popov ghosts are defined. The corresponding BRST transformations are found. The harmonic superspace quantization of the N=2 gauge theory turns out to be rather simple and has many parallels with that for the standard (N=0) Yang-Mills theory. In particular, no ghosts-forghosts are needed

Study of Ion Acoustic Wave Damping through Green's Functions

DEFF Research Database (Denmark)

Hsuan, H.C.S.; Jensen, Vagn Orla

1973-01-01

Green's function analyses of ion acoustic waves in streaming plasmas show that, in general, the waves damp algebraically rather than exponentially with distance from exciter.......Green's function analyses of ion acoustic waves in streaming plasmas show that, in general, the waves damp algebraically rather than exponentially with distance from exciter....

Green's functions on spheres and on closed Robertson--Walker spacetimes

International Nuclear Information System (INIS)

Hahne, G.E.

1975-01-01

The objective of this investigation was to carry the theory and calculations of certain Green functions as far as seemed possible toward applications, in particular toward the calculation of the rate of spontaneous creation of scalar particles by strong gravitational fields. The latter calculation has not yet been carried out in full on account of its apparent mathematical intractability. As an introduction to Green functions concern is with the Green function for the Laplacian operator Δ (or NABLA 2 ) and the Helmholtz operator DELTA + omega 2 on n-spheres, with a few examples worked out. Subsequently, Green's functions for massless particles on Einstein spacetimes of two (S 1 x T) and four (S 3 x T) dimensions are obtained. By a fortuitous circumstance the conformally invariant equation in the case of the 4-dimensional Einstein space could be worked out in detail. The conformally invariant case predicts no spontaneous creation of particles, however. In the final calculation a special kind of Green function associated with the Klein-Gordon equation was related to the particle creation amplitude for an Einstein universe. (Diss. Abstr. Int., B)

Green functions in a super self-dual Yang-Mills background

International Nuclear Information System (INIS)

McArthur, I.N.

1984-01-01

In euclidean supersymmetric theories of chiral superfields and vector superfields coupled to a super-self-dual Yang-Mills background, we define Green functions for the Laplace-type differential operators which are obtained from the quadratic parot the action. These Green functions are expressed in terms of the Green function on the space of right chiral superfields, and an explicit expression for the right chiral Green function in the fundamental representation of an SU(n) gauge group is presented using the supersymmetric version of the ADHM formalism. The superfield kernels associated with the Laplace-type operators are used to obtain the one-loop quantum corrections to the super-self-dual Yang-Mills action, and also to provide a superfield version of the super-index theorems for the components of chiral superfields in a self-dual background. (orig.)

Green's functions for off-shell electromagnetism and spacelike correlations

International Nuclear Information System (INIS)

Land, M.C.; Horwitz, L.P.

1991-01-01

The requirement of gauge invariance for the Schwinger-DeWitt equations, interpreted as a manifestly covariant quantum theory for the evolution of a system in spacetime, implies the existence of a five-dimensional pre-Maxwell field on the manifold of spacetime and proper time τ. The Maxwell theory is contained in this theory; integration of the field equations over τ restores the Maxwell equations with the usual interpretation of the sources. Following Schwinger's techniques, the authors study the Green's functions for the five dimensional hyperbolic field equations for both signatures ± [corresponding to O(4, 1) or O(3, 2) symmetry of the field equations] of the proper time derivative. The classification of the Green's functions follows that of the four-dimensional theory for massive fields, for which the mass squared may be positive or negative, respectively. The Green's function for the five-dimensional field are then given by the Fourier transform over the mass parameter. They derive the Green's functions corresponding to the principal part Δ P and the homogeneous function Δ t ; all of the Green's functions can be expressed in terms of these, as for the usual field equations with definite mass. In the O(3, 2) case, the principal part function has support for x 2 ≥ τ 2 , corresponding to spacelike propagation, as well as along the light cone X 2 = 0 (for τ = 0). There can be no transmission of information in spacelike directions, with this propagator, since the Maxwell field, obtained by integration over τ, does not contain this component of the support. Measurements are characterized by such an integration. The spacelike field therefore can dynamically establish spacelike correlations

The non-equilibrium Green's function method for nanoscale device simulation

CERN Document Server

Pourfath, Mahdi

2014-01-01

For modeling the transport of carriers in nanoscale devices, a Green-function formalism is the most accurate approach. Due to the complexity of the formalism, one should have a deep understanding of the underlying principles and use smart approximations and numerical methods for solving the kinetic equations at a reasonable computational time. In this book the required concepts from quantum and statistical mechanics and numerical methods for calculating Green functions are presented. The Green function is studied in detail for systems both under equilibrium and under nonequilibrium conditions. Because the formalism enables rigorous modeling of different scattering mechanisms in terms of self-energies, but an exact evaluation of self-energies for realistic systems is not possible, their approximation and inclusion in the quantum kinetic equations of the Green functions are elaborated. All the elements of the kinetic equations, which are the device Hamiltonian, contact self-energies, and scattering self-energie...

Boundary conditions for quasiclassical Green's function for superfluid Fermi systems

International Nuclear Information System (INIS)

Nagai, K.; Hara, J.

1988-01-01

The authors show that the quasiclassical Green's Function for Fermi liquids can be constructed from the solutions of the Bogoliubov-de Gennes equation within the Andreev approximation and derive self-consistent relations to be satisfied by the quasiclassical Green's function at the surfaces. The so-called normalization condition for the quasiclassical Green's function is obtained from this self-consistent relation. They consider a specularly reflecting wall, a randomly rippled wall, and a proximity boundary as model surfaces. Their boundary condition for the randomly rippled wall is different from that derived by Buchholtz and Rainer and Buchholtz

Functional Use Change in Green Spaces: A Case Study of Kirklareli Province

Science.gov (United States)

Sat Gungor, Beyza; Culha Ozanguc, Kadiriye

2017-10-01

Green spaces which are one of the most important public spaces in urban design have an important role on qualified daily urban life. People escape from intense work pressure and traffic jam of metropoles to those urban green areas to take a breath even they cover a small size. In time, people’s expectations from green spaces as functional and quantitative needs are changing. This change occurs due to increasing population and as the character of the urban life. This study examines the functional use and quantitative change of urban green spaces of Kırklareli Province from past to present. Kırklareli is a border city to Bulgaria which is located in north-west part of Turkey and this gives a transitional and a multicultural character to the city. The population is about 67360. In the course of time; green space needs have increased by the increasing population. In addition to this, green spaces’ functional use change has been identified. According to the results of the study; from the aspect of the green space standards, Kırklareli found above standards with 17.5 m2 per capita, but on the other hand, sport and playground areas found insufficient. The Oldest and the newest city plans of Kırklareli (1940s and 2012s cadastral plans) have been compared and site surveys implemented as the methodology. In site survey, current green spaces’ functional uses as sport or playground are observed and determined and also current quantitative measure of the green spaces are verified. Urban green spaces in Kırklareli Province evaluated through considering world’s most populated urban green space standards and Turkey’s standards. This study utilizes to compose a substructure of the urban green space. Determined deficiencies and inadequacies of green spaces and functional needs in this study, can guide to further studies and implementations of Kırklareli Municipality.

Vector Green's function algorithm for radiative transfer in plane-parallel atmosphere

International Nuclear Information System (INIS)

Qin Yi; Box, Michael A.

2006-01-01

Green's function is a widely used approach for boundary value problems. In problems related to radiative transfer, Green's function has been found to be useful in land, ocean and atmosphere remote sensing. It is also a key element in higher order perturbation theory. This paper presents an explicit expression of the Green's function, in terms of the source and radiation field variables, for a plane-parallel atmosphere with either vacuum boundaries or a reflecting (BRDF) surface. Full polarization state is considered but the algorithm has been developed in such way that it can be easily reduced to solve scalar radiative transfer problems, which makes it possible to implement a single set of code for computing both the scalar and the vector Green's function

Electrical tensor Green functions for cylindrical waveguides

International Nuclear Information System (INIS)

Prijmenko, S.D.; Papkovich, V.G.; Khizhnyak, N.A.

1988-01-01

Formation of electrical tensor Green functions for cylindrical waveguides is considered. Behaviour of these functions in the source region is studied. Cases of electrical tensor Green functions for vector potential G E (r-vector, r'-vector) and electric field G e (r-vector, r'-vector) are analysed. When forming G E (r-vector, r'-vector), its dependence on lateral coordinates is taken into account by means of two-dimensional fundamental vector Hansen functions, several methods are used to take into account the dependence on transverse coordinate. When forming G e (r-vector, r'-vector) we use the fact that G E (r-vector, r'-vector) and G e (r-vector, r'-vector) are the generalized functions. It is shown that G e (r-vector, r'-vector) behaviour in the source region is defined by a singular term, which properties are described by the delta-function. Two variants of solving the problem of defining singular and regular sides of tensor function G E (r-vector, r'-vector) are presented. 23 refs

Gluon Green functions free of quantum fluctuations

Directory of Open Access Journals (Sweden)

A. Athenodorou

2016-09-01

Full Text Available This letter reports on how the Wilson flow technique can efficaciously kill the short-distance quantum fluctuations of 2- and 3-gluon Green functions, remove the ΛQCD scale and destroy the transition from the confining non-perturbative to the asymptotically-free perturbative sector. After the Wilson flow, the behavior of the Green functions with momenta can be described in terms of the quasi-classical instanton background. The same behavior also occurs, before the Wilson flow, at low-momenta. This last result permits applications as, for instance, the detection of instanton phenomenological properties or a determination of the lattice spacing only from the gauge sector of the theory.

Floquet-Green function formalism for harmonically driven Hamiltonians

International Nuclear Information System (INIS)

Martinez, D F

2003-01-01

A method is proposed for the calculation of the Floquet-Green function of a general Hamiltonian with harmonic time dependence. We use matrix continued fractions to derive an expression for the 'dynamical effective potential' that can be used to calculate the Floquet-Green function of the system. We demonstrate the formalism for the simple case of a space-periodic (in the tight-binding approximation) Hamiltonian with a defect whose on-site energy changes harmonically with time. We study the local density of states for this system and the behaviour of the localized states as a function of the different parameters that characterize the system

Modeling photonic crystal waveguides with noncircular geometry using green function method

International Nuclear Information System (INIS)

Uvarovaa, I.; Tsyganok, B.; Bashkatov, Y.; Khomenko, V.

2012-01-01

Currently in the field of photonics is an acute problem fast and accurate simulation photonic crystal waveguides with complex geometry. This paper describes an improved method of Green's functions for non-circular geometries. Based on comparison of selected efficient numerical method for finding the eigenvalues for the Green's function method for non-circular holes chosen effective method for our purposes. Simulation is realized in Maple environment. The simulation results confirmed experimentally. Key words: photonic crystal, waveguide, modeling, Green function, complex geometry

An efficient and accurate method to obtain the energy-dependent Green function for general potentials

International Nuclear Information System (INIS)

Kramer, T; Heller, E J; Parrott, R E

2008-01-01

Time-dependent quantum mechanics provides an intuitive picture of particle propagation in external fields. Semiclassical methods link the classical trajectories of particles with their quantum mechanical propagation. Many analytical results and a variety of numerical methods have been developed to solve the time-dependent Schroedinger equation. The time-dependent methods work for nearly arbitrarily shaped potentials, including sources and sinks via complex-valued potentials. Many quantities are measured at fixed energy, which is seemingly not well suited for a time-dependent formulation. Very few methods exist to obtain the energy-dependent Green function for complicated potentials without resorting to ensemble averages or using certain lead-in arrangements. Here, we demonstrate in detail a time-dependent approach, which can accurately and effectively construct the energy-dependent Green function for very general potentials. The applications of the method are numerous, including chemical, mesoscopic, and atomic physics

Green's function method and its application to verification of diffusion models of GASFLOW code

International Nuclear Information System (INIS)

Xu, Z.; Travis, J.R.; Breitung, W.

2007-07-01

To validate the diffusion model and the aerosol particle model of the GASFLOW computer code, theoretical solutions of advection diffusion problems are developed by using the Green's function method. The work consists of a theory part and an application part. In the first part, the Green's functions of one-dimensional advection diffusion problems are solved in infinite, semi-infinite and finite domains with the Dirichlet, the Neumann and/or the Robin boundary conditions. Novel and effective image systems especially for the advection diffusion problems are made to find the Green's functions in a semi-infinite domain. Eigenfunction method is utilized to find the Green's functions in a bounded domain. In the case, key steps of a coordinate transform based on a concept of reversed time scale, a Laplace transform and an exponential transform are proposed to solve the Green's functions. Then the product rule of the multi-dimensional Green's functions is discussed in a Cartesian coordinate system. Based on the building blocks of one-dimensional Green's functions, the multi-dimensional Green's function solution can be constructed by applying the product rule. Green's function tables are summarized to facilitate the application of the Green's function. In the second part, the obtained Green's function solutions benchmark a series of validations to the diffusion model of gas species in continuous phase and the diffusion model of discrete aerosol particles in the GASFLOW code. Perfect agreements are obtained between the GASFLOW simulations and the Green's function solutions in case of the gas diffusion. Very good consistencies are found between the theoretical solutions of the advection diffusion equations and the numerical particle distributions in advective flows, when the drag force between the micron-sized particles and the conveying gas flow meets the Stokes' law about resistance. This situation is corresponding to a very small Reynolds number based on the particle

The method of images and Green's function for spherical domains

International Nuclear Information System (INIS)

Gutkin, Eugene; Newton, Paul K

2004-01-01

Motivated by problems in electrostatics and vortex dynamics, we develop two general methods for constructing Green's function for simply connected domains on the surface of the unit sphere. We prove a Riemann mapping theorem showing that such domains can be conformally mapped to the upper hemisphere. We then categorize all domains on the sphere for which Green's function can be constructed by an extension of the classical method of images. We illustrate our methods by several examples, such as the upper hemisphere, geodesic triangles, and latitudinal rectangles. We describe the point vortex motion in these domains, which is governed by a Hamiltonian determined by the Dirichlet Green's function

A hybrid method for the parallel computation of Green's functions

International Nuclear Information System (INIS)

Petersen, Dan Erik; Li Song; Stokbro, Kurt; Sorensen, Hans Henrik B.; Hansen, Per Christian; Skelboe, Stig; Darve, Eric

2009-01-01

Quantum transport models for nanodevices using the non-equilibrium Green's function method require the repeated calculation of the block tridiagonal part of the Green's and lesser Green's function matrices. This problem is related to the calculation of the inverse of a sparse matrix. Because of the large number of times this calculation needs to be performed, this is computationally very expensive even on supercomputers. The classical approach is based on recurrence formulas which cannot be efficiently parallelized. This practically prevents the solution of large problems with hundreds of thousands of atoms. We propose new recurrences for a general class of sparse matrices to calculate Green's and lesser Green's function matrices which extend formulas derived by Takahashi and others. We show that these recurrences may lead to a dramatically reduced computational cost because they only require computing a small number of entries of the inverse matrix. Then, we propose a parallelization strategy for block tridiagonal matrices which involves a combination of Schur complement calculations and cyclic reduction. It achieves good scalability even on problems of modest size.

On Green's function for 3-D wave-body interaction in a channel

DEFF Research Database (Denmark)

Xia, Jinzhu

1997-01-01

series of images is evaluated accurately based on an asmptotic analysis. It is demonstrated that the Green's function has a square-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's function has a square......An analytical and numerical study is presented for efficient evaluation of the Green's function that satisfies the linear free surface condition and the non-penetration condition on the channel bottomand the side walls. the formulation is based on the open-sea green's function and the complete......-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's funciton presented in the present paper are believed to have an absolute accuracy of 10-5....

Euclidean scalar Green's functions near the black hole and black brane horizons

International Nuclear Information System (INIS)

Haba, Z

2009-01-01

We discuss approximations of the Riemannian geometry near the horizon. If a (D + 1)-dimensional manifold N has a bifurcate Killing horizon then we approximate N by a product of the two-dimensional Rindler space R 2 and a (D - 1)-dimensional Riemannian manifold M. We obtain approximate formulae for scalar Green's functions. We study the behavior of the Green's functions near the horizon and their dimensional reduction. We show that if M is compact then the Green's function near the horizon can be approximated by the Green's function of the two-dimensional quantum field theory. The correction term is exponentially small away from the horizon. We extend the results to black brane solutions of supergravity in 10 and 11 dimensions. The near-horizon geometry can be approximated by N=AdS p xS q . We discuss the Euclidean Green's functions on N and their behavior near the horizon.

Nonequilibrium statistical Zubarev's operator and Green's functions for an inhomogeneous electron gas

Directory of Open Access Journals (Sweden)

P.Kostrobii

2006-01-01

Full Text Available Nonequilibrium properties of an inhomogeneous electron gas are studied using the method of the nonequilibrium statistical operator by D.N. Zubarev. Generalized transport equations for the mean values of inhomogeneous operators of the electron number density, momentum density, and total energy density for weakly and strongly nonequilibrium states are obtained. We derive a chain of equations for the Green's functions, which connects commutative time-dependent Green's functions "density-density", "momentum-momentum", "enthalpy-enthalpy" with reduced Green's functions of the generalized transport coefficients and with Green's functions for higher order memory kernels in the case of a weakly nonequilibrium spatially inhomogeneous electron gas.

Quantum-mechanical Green's functions and nonlinear superposition law

International Nuclear Information System (INIS)

Nassar, A.B.; Bassalo, J.M.F.; Antunes Neto, H.S.; Alencar, P. de T.S.

1986-01-01

The quantum-mechanical Green's function is derived for the problem of a time-dependent variable mass particle subject to a time-dependent forced harmonic oscillator potential by taking direct recourse of the corresponding Schroedinger equation. Through the usage of the nonlinear superposition law of Ray and Reid, it is shown that such a Green's function can be obtained from that for the problem of a particle with unit (constant) mass subject to either a forced harmonic potential with constant frequency or only to a time-dependent linear field. (Author) [pt

Quantum-mechanical Green's function and nonlinear superposition law

International Nuclear Information System (INIS)

Nassar, A.B.; Bassalo, J.M.F.; Antunes Neto, H.S.; Alencar, P.T.S.

1986-01-01

It is derived the quantum-mechanical Green's function for the problem of a time-dependent variable mass particle subject to a time-dependent forced harmonic-oscillator potential by taking direct recourse of the corresponding Schroedinger equation. Through the usage of the nonlinear superposition law of Ray and Reid, it is shown that such a Green's function can be obtained from that for the problem of a particle with unit (constant) mass subject to either a forced harmonic potential with constant frequency or only to a time-dependent linear field

Temporal quadratic expansion nodal Green's function method

International Nuclear Information System (INIS)

Liu Cong; Jing Xingqing; Xu Xiaolin

2000-01-01

A new approach is presented to efficiently solve the three-dimensional space-time reactor dynamics equation which overcomes the disadvantages of current methods. In the Temporal Quadratic Expansion Nodal Green's Function Method (TQE/NGFM), the Quadratic Expansion Method (QEM) is used for the temporal solution with the Nodal Green's Function Method (NGFM) employed for the spatial solution. Test calculational results using TQE/NGFM show that its time step size can be 5-20 times larger than that of the Fully Implicit Method (FIM) for similar precision. Additionally, the spatial mesh size with NGFM can be nearly 20 times larger than that using the finite difference method. So, TQE/NGFM is proved to be an efficient reactor dynamics analysis method

Green-diode-pumped femtosecond Ti:Sapphire laser with up to 450 mW average power.

Science.gov (United States)

Gürel, K; Wittwer, V J; Hoffmann, M; Saraceno, C J; Hakobyan, S; Resan, B; Rohrbacher, A; Weingarten, K; Schilt, S; Südmeyer, T

2015-11-16

We investigate power-scaling of green-diode-pumped Ti:Sapphire lasers in continuous-wave (CW) and mode-locked operation. In a first configuration with a total pump power of up to 2 W incident onto the crystal, we achieved a CW power of up to 440 mW and self-starting mode-locking with up to 200 mW average power in 68-fs pulses using semiconductor saturable absorber mirror (SESAM) as saturable absorber. In a second configuration with up to 3 W of pump power incident onto the crystal, we achieved up to 650 mW in CW operation and up to 450 mW in 58-fs pulses using Kerr-lens mode-locking (KLM). The shortest pulse duration was 39 fs, which was achieved at 350 mW average power using KLM. The mode-locked laser generates a pulse train at repetition rates around 400 MHz. No complex cooling system is required: neither the SESAM nor the Ti:Sapphire crystal is actively cooled, only air cooling is applied to the pump diodes using a small fan. Because of mass production for laser displays, we expect that prices for green laser diodes will become very favorable in the near future, opening the door for low-cost Ti:Sapphire lasers. This will be highly attractive for potential mass applications such as biomedical imaging and sensing.

A relationship between scalar Green functions on hyperbolic and Euclidean Rindler spaces

International Nuclear Information System (INIS)

Haba, Z

2007-01-01

We derive a formula connecting in any dimension the Green function on the (D + 1)-dimensional Euclidean Rindler space and the one for a minimally coupled scalar field with a mass m in the D-dimensional hyperbolic space. The relation takes a simple form in the momentum space where the Green functions are equal at the momenta (p 0 , p) for Rindler and (m,p-hat) for hyperbolic space with a simple additive relation between the squares of the mass and the momenta. The formula has applications to finite temperature Green functions, Green functions on the cone and on the (compactified) Milne spacetime. Analytic continuations and interacting quantum fields are briefly discussed

Surface Functionalization of “Rajshahi Silk” Using Green Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Sakil Mahmud

2017-09-01

Full Text Available In this study, a novel functionalization approach has been addressed by using sodium alginate (Na-Alg assisted green silver nanoparticles (AgNPs on traditional “Rajshahi silk” fabric via an exhaustive method. The synthesized nanoparticles and coated silk fabrics were characterized by different techniques, including ultraviolet–visible spectroscopy (UV–vis spectra, scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray spectroscopy (EDS, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and Fourier transform infrared spectroscopy (FT-IR, which demonstrated that AgNPs with an average size of 6–10 nm were consistently deposited in the fabric surface under optimized conditions (i.e., pH 4, temperature 40 °C, and time 40 min. The silk fabrics treated with AgNPs showed improved colorimetric values and color fastness properties. Moreover, the UV-protection ability and antibacterial activity, as well as other physical properties—including tensile properties, the crease recovery angle, bending behavior, the yellowness index, and wettability (surface contact angle of the AgNPs-coated silk were distinctly augmented. Therefore, green AgNPs-coated traditional silk with multifunctional properties has high potential in the textile industry.

Axioms for Euclidean Green's functions. Pt. 2

International Nuclear Information System (INIS)

Osterwalder, K.; Schrader, R.

1975-01-01

We give new (necessary and) sufficient conditions for Euclidean Green's functions to have analytic continuations to a relativistic field theory. These results extend and correct a previous paper. (orig.) [de

Nonequilibrium Green's function theory for nonadiabatic effects in quantum electron transport

Science.gov (United States)

Kershaw, Vincent F.; Kosov, Daniel S.

2017-12-01

We develop nonequilibrium Green's function-based transport theory, which includes effects of nonadiabatic nuclear motion in the calculation of the electric current in molecular junctions. Our approach is based on the separation of slow and fast time scales in the equations of motion for Green's functions by means of the Wigner representation. Time derivatives with respect to central time serve as a small parameter in the perturbative expansion enabling the computation of nonadiabatic corrections to molecular Green's functions. Consequently, we produce a series of analytic expressions for non-adiabatic electronic Green's functions (up to the second order in the central time derivatives), which depend not solely on the instantaneous molecular geometry but likewise on nuclear velocities and accelerations. An extended formula for electric current is derived which accounts for the non-adiabatic corrections. This theory is concisely illustrated by the calculations on a model molecular junction.

A passive inverse filter for Green's function retrieval.

Science.gov (United States)

Gallot, Thomas; Catheline, Stefan; Roux, Philippe; Campillo, Michel

2012-01-01

Passive methods for the recovery of Green's functions from ambient noise require strong hypotheses, including isotropic distribution of the noise sources. Very often, this distribution is nonisotropic, which introduces bias in the Green's function reconstruction. To minimize this bias, a spatiotemporal inverse filter is proposed. The method is tested on a directive noise field computed from an experimental active seismic data set. The results indicate that the passive inverse filter allows the manipulation of the spatiotemporal degrees of freedom of a complex wave field, and it can efficiently compensate for the noise wavefield directivity. © 2012 Acoustical Society of America.

Multiloop world-line Green functions from string theory

International Nuclear Information System (INIS)

Roland, K.; Sato, H.T.

1996-01-01

We show how the multiloop bosonic Green function of closed string theory reduces to the world-line Green function as defined by Schmidt and Schubert in the limit where the string world-sheet degenerates into a Φ 3 particle diagram. To obtain this correspondence we have to make an appropriate choice of the local coordinates defined on the degenerate string world sheet. We also present a set of simple rules that specify, in the explicit setting of the Schottky parametrization, which is the corner of moduli space corresponding to a given multiloop Φ 3 diagram. (orig.)

Development of thermal stress screening method. Application of green function method

International Nuclear Information System (INIS)

Furuhashi, Ichiro; Shibamoto, Hiroshi; Kasahara, Naoto

2004-01-01

This work was achieved for the development of the screening method of thermal transient stresses in FBR components. We proposed an approximation method for evaluations of thermal stress under variable heat transfer coefficients (non-linear problems) using the Green functions of thermal stresses with constant heat transfer coefficients (linear problems). Detailed thermal stress analyses provided Green functions for a skirt structure and a tube-sheet of Intermediate Heat Exchanger. The upper bound Green functions were obtained by the analyses using those upper bound heat transfer coefficients. The medium and the lower bound Green functions were got by the analyses of those under medium and the lower bound heat transfer coefficients. Conventional evaluations utilized the upper bound Green functions. On the other hand, we proposed a new evaluation method by using the upper bound, medium and the lower bound Green functions. The comparison of above results gave the results as follows. The conventional evaluations were conservative and appropriate for the cases under one fluid thermal transient structure such as the skirt. The conventional evaluations were generally conservative for the complicated structures under two or more fluids thermal transients such as the tube-sheet. But the danger locations could exists for the complicated structures under two or more fluids transients, namely the conventional evaluations were non-conservative. The proposed evaluations gave good estimations for these complicated structures. Though above results, we have made the basic documents of the screening method of thermal transient stresses using the conventional method and the new method. (author)

Finite medium Green's function solutions to nuclide transport in porous media

International Nuclear Information System (INIS)

Oston, S.G.

1979-01-01

Current analytical techniques for predicting the transport of nuclides in porous materials center on the Green's function approach - i.e., determining the response characteristics of a geologic pathway to an impulse function input. To data, the analyses all have set the boundary conditions needed to solve the 1-D transport equation as though each pathway were infinite in length. The purpose of this work is to critically examine the effect that this infinite pathway assumption has on Green's function models of nuclide transport in porous media. The work described herein has directly attacked the more difficult problem of obtaining suitable Green's functions for finite pathways whose dimensions, in fact, may not be much greater than the diffusion length. Two different finite media Green's functions describing the nuclide mass flux have been determined, depending on whether the pathway is terminated by a high or a low flow resistance at the outlet end. Pulse shapes and peak amplitudes have been computed for each Green's function over a wide range of geohydrologic parameters. These results have been compared to both infinite and semi-infinite medium solutions. It was found that predicted pulse shapes are quite sensitive to selection of a Green's function model for short pathways only. For long pathways all models tend toward a symmetric Gaussian flux-time history at the outlet. Thus, the results of our previous waste transport studies using the infinite pathway assumption are still generally valid because they always included at least one long pathway. It was also found that finite medium models offer some unique computational advantages for evaluating nuclide transport in a series of connecting pathways

Dual number algebra method for Green's function derivatives in 3D magneto-electro-elasticity

Science.gov (United States)

Dziatkiewicz, Grzegorz

2018-01-01

The Green functions are the basic elements of the boundary element method. To obtain the boundary integral formulation the Green function and its derivative should be known for the considered differential operator. Today the interesting group of materials are electronic composites. The special case of the electronic composite is the magnetoelectroelastic continuum. The mentioned continuum is a model of the piezoelectric-piezomagnetic composites. The anisotropy of their physical properties makes the problem of Green's function determination very difficult. For that reason Green's functions for the magnetoelectroelastic continuum are not known in the closed form and numerical methods should be applied to determine such Green's functions. These means that the problem of the accurate and simply determination of Green's function derivatives is even harder. Therefore in the present work the dual number algebra method is applied to calculate numerically the derivatives of 3D Green's functions for the magnetoelectroelastic materials. The introduced method is independent on the step size and it can be treated as a special case of the automatic differentiation method. Therefore, the dual number algebra method can be applied as a tool for checking the accuracy of the well-known finite difference schemes.

Maximum entropy formalism for the analytic continuation of matrix-valued Green's functions

Science.gov (United States)

Kraberger, Gernot J.; Triebl, Robert; Zingl, Manuel; Aichhorn, Markus

2017-10-01

We present a generalization of the maximum entropy method to the analytic continuation of matrix-valued Green's functions. To treat off-diagonal elements correctly based on Bayesian probability theory, the entropy term has to be extended for spectral functions that are possibly negative in some frequency ranges. In that way, all matrix elements of the Green's function matrix can be analytically continued; we introduce a computationally cheap element-wise method for this purpose. However, this method cannot ensure important constraints on the mathematical properties of the resulting spectral functions, namely positive semidefiniteness and Hermiticity. To improve on this, we present a full matrix formalism, where all matrix elements are treated simultaneously. We show the capabilities of these methods using insulating and metallic dynamical mean-field theory (DMFT) Green's functions as test cases. Finally, we apply the methods to realistic material calculations for LaTiO3, where off-diagonal matrix elements in the Green's function appear due to the distorted crystal structure.

Green function for three-wave coupling problems

International Nuclear Information System (INIS)

Molevich, N E

2001-01-01

The Green function is found for three-wave coupling problems. The function was used for analysis of parametric amplification in dissipative and active media. It is shown that the parametric increment in active media can become exponential. As an example, the nonstationary stimulated scattering of electromagnetic waves by sound and temperatures waves is considered. (nonlinear optical phenomena)

Construction of Green's functions for the Black-Scholes equation

Directory of Open Access Journals (Sweden)

Yuri A. Melnikov

2007-11-01

Full Text Available A technique is proposed for the construction of Green's functions for terminal-boundary value problems of the Black-Scholes equation. The technique permits an application to a variety of problems that vary by boundary conditions imposed. This is possible by extension of an approach that was earlier developed for partial differential equations in applied mechanics. The technique is based on the method of integral Laplace transform and the method of variation of parameters. It provides closed form analytic representations for the constructed Green's functions.

Green's theorem and Green's functions for the steady-state cosmic-ray equation of transport

International Nuclear Information System (INIS)

Webb, G.M.; Gleeson, L.J.

1977-01-01

Green's Theorem is developed for the spherically-symmetric steady-state cosmic-ray equation of transport in interplanetary space. By means of it the momentum distribution function F 0 (r,p), (r=heliocentric distance, p=momentum) can be determined in a region rsub(a) 0 . Examples of Green's functions are given for the case rsub(a)=0, rsub(b)=infinity and derived for the cases of finite rsub(a) and rsub(b). The diffusion coefficient kappa is assumed of the form kappa=kappa 0 (p)rsup(b). The treatment systematizes the development of all analytic solutions for steady-state solar and galactic cosmic-ray propagation and previous solutions form a subset of the present solutions. (Auth.)

Fitting a function to time-dependent ensemble averaged data

DEFF Research Database (Denmark)

Fogelmark, Karl; Lomholt, Michael A.; Irbäck, Anders

2018-01-01

Time-dependent ensemble averages, i.e., trajectory-based averages of some observable, are of importance in many fields of science. A crucial objective when interpreting such data is to fit these averages (for instance, squared displacements) with a function and extract parameters (such as diffusion...... method, weighted least squares including correlation in error estimation (WLS-ICE), to particle tracking data. The WLS-ICE method is applicable to arbitrary fit functions, and we provide a publically available WLS-ICE software....

The one-loop Green's functions of dimensionally reduced gauge theories

International Nuclear Information System (INIS)

Ketov, S.V.; Prager, Y.S.

1988-01-01

The dimensional regularization technique as well as that by dimensional reduction is applied to the calculation of the regularized one-loop Green's functions in dsub(o)-dimensional Yang-Mills theory with real massless scalars and spinors in arbitrary (real) representations of a gauge group G. As a particular example, the super-symmetrically regularized one-loop Green's functions of the N=4 supersymmetric Yang-Mills model are derived. (author). 17 refs

THE GREEN'S FUNCTIONS OF SUPERCONDUCTIVITY- A REVIEW

African Journals Online (AJOL)

users

2013-02-21

Feb 21, 2013 ... We present some basic Green's functions of superconductivity, ... show that the Gorkov interaction under a certain condition sustains .... We may then apply Wick's theorem(Lifshitz and Pitayevsky,1980) to the eqn(18) to have.

Exact solutions for fermionic Green's functions in the Bloch-Nordsieck approximation of QED

International Nuclear Information System (INIS)

Kernemann, A.; Stefanis, N.G.

1989-01-01

A set of new closed-form solutions for fermionic Green's functions in the Bloch-Nordsieck approximation of QED is presented. A manifestly covariant phase-space path-integral method is applied for calculating the n-fermion Green's function in a classical external field. In the case of one and two fermions, explicit expressions for the full Green's functions are analytically obtained, with renormalization carried out in the modified minimal subtraction scheme. The renormalization constants and the corresponding anomalous dimensions are determined. The mass-shell behavior of the two-fermion Green's function is investigated in detail. No assumptions are made concerning the structure of asymptotic states and no IR cutoff is used in the calculations

Green's function approach to neutron flux discontinuities

International Nuclear Information System (INIS)

Saad, E.A.; El-Wakil, S.A.

1980-01-01

The present work is devoted to the presentation of analytical method for the calculation of elastically and inelastically slowed down neutrons in an infinite non-absorbing medium. On the basis of the central limit theory (CLT) and the integral transform technique the slowing down equation including inelastic scattering, in terms of the Green function of elastic scattering, is solved. The Green function is decomposed according to the number of collisions. Placzec discontinuity associated with elastic scattering in addition to two discontinuities due to inelastic scattering are investigated. Numerical calculations for Fe 56 show that the elastic discontinuity produces about 41.8% change in the collision density whilst the ratio of the inelastic collision density discontinuity at qsub(o)sup(+) to the Placzec discontinuity at usub(o) + 1n 1/oc gives 55.7 percent change. (author)

Wave function collapse implies divergence of average displacement

OpenAIRE

Marchewka, A.; Schuss, Z.

2005-01-01

We show that propagating a truncated discontinuous wave function by Schr\\"odinger's equation, as asserted by the collapse axiom, gives rise to non-existence of the average displacement of the particle on the line. It also implies that there is no Zeno effect. On the other hand, if the truncation is done so that the reduced wave function is continuous, the average coordinate is finite and there is a Zeno effect. Therefore the collapse axiom of measurement needs to be revised.

Green's functions for spin half field theory in Rindler space

Energy Technology Data Exchange (ETDEWEB)

Iyer, B R; Kumar, Arvind [Birla Inst. of Tech., Ranchi (India). Dept. of Physics

1977-11-01

The solutions of Dirac equation in different regions of the complete extension of Rindler space are obtained near the event horizons and in the asymptotic limits. Continuity of these solutions across the event horizons is established. The Green's functions are written down in the two casually disconnected regions, continued in the future (F) and past (P) regions using the techniques a la Boulware and a consistent scheme of Green's functions in all regions is exhibited.

Computing the real-time Green's Functions of large Hamiltonian matrices

OpenAIRE

Iitaka, Toshiaki

1998-01-01

A numerical method is developed for calculating the real time Green's functions of very large sparse Hamiltonian matrices, which exploits the numerical solution of the inhomogeneous time-dependent Schroedinger equation. The method has a clear-cut structure reflecting the most naive definition of the Green's functions, and is very suitable to parallel and vector supercomputers. The effectiveness of the method is illustrated by applying it to simple lattice models. An application of this method...

Accurate calculation of Green functions on the d-dimensional hypercubic lattice

International Nuclear Information System (INIS)

Loh, Yen Lee

2011-01-01

We write the Green function of the d-dimensional hypercubic lattice in a piecewise form covering the entire real frequency axis. Each piece is a single integral involving modified Bessel functions of the first and second kinds. The smoothness of the integrand allows both real and imaginary parts of the Green function to be computed quickly and accurately for any dimension d and any real frequency, and the computational time scales only linearly with d.

Preequilibrium decay models and the quantum Green function method

International Nuclear Information System (INIS)

Zhivopistsev, F.A.; Rzhevskij, E.S.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki)

1977-01-01

The nuclear process mechanism and preequilibrium decay involving complex particles are expounded on the basis of the Green function formalism without the weak interaction assumptions. The Green function method is generalized to a general nuclear reaction: A+α → B+β+γ+...rho, where A is the target nucleus, α is a complex particle in the initial state, B is the final nucleus, and β, γ, ... rho are nuclear fragments in the final state. The relationship between the generalized Green function and Ssub(fi)-matrix is established. The resultant equations account for: 1) direct and quasi-direct processes responsible for the angular distribution asymmetry of the preequilibrium component; 2) the appearance of addends corresponding to the excitation of complex states of final nucleus; and 3) the relationship between the preequilibrium decay model and the general models of nuclear reaction theories (Lippman-Schwinger formalism). The formulation of preequilibrium emission via the S(T) matrix allows to account for all the differential terms in succession important to an investigation of the angular distribution assymetry of emitted particles

Recent Advances in the Korringa-Kohn-Rostoker Green Function Method

Directory of Open Access Journals (Sweden)

Zeller Rudolf

2014-01-01

Full Text Available The Korringa-Kohn-Rostoker (KKR Green function (GF method is a technique for all-electron full-potential density-functional calculations. Similar to the historical Wigner-Seitz cellular method, the KKR-GF method uses a partitioning of space into atomic Wigner-Seitz cells. However, the numerically demanding wave-function matching at the cell boundaries is avoided by use of an integral equation formalism based on the concept of reference Green functions. The advantage of this formalism will be illustrated by the recent progress made for very large systems with thousands of inequivalent atoms and for very accurate calculations of atomic forces and total energies.

Function reconstruction from noisy local averages

International Nuclear Information System (INIS)

Chen Yu; Huang Jianguo; Han Weimin

2008-01-01

A regularization method is proposed for the function reconstruction from noisy local averages in any dimension. Error bounds for the approximate solution in L 2 -norm are derived. A number of numerical examples are provided to show computational performance of the method, with the regularization parameters selected by different strategies

Green's functions for spin half field theory in Rindler space

International Nuclear Information System (INIS)

Iyer, B.R.; Kumar, Arvind

1977-01-01

The solutions of Dirac equation in different regions of the complete extension of Rindler space are obtained near the event horizons and in the asymptotic limits. Continuity of these solutions across the event horizons is established. The Green's functions are written down in the two casually disconnected regions, continued in the future (F) and past (P) regions using the techniques a la Boulware and a consistent scheme of Green's functions in all regions is exhibited. (author)

Bi-conformal symmetry and static Green functions in the Schwarzschild-Tangherlini spacetimes

International Nuclear Information System (INIS)

Frolov, Valeri P.; Zelnikov, Andrei

2015-01-01

We study a static massless minimally coupled scalar field created by a source in a static D-dimensional spacetime. We demonstrate that the corresponding equation for this field is invariant under a special transformation of the background metric. This transformation consists of the static conformal transformation of the spatial part of the metric accompanied by a properly chosen transformation of the red-shift factor. Both transformations are determined by one function Ω of the spatial coordinates. We show that in a case of higher dimensional spherically symmetric black holes one can find such a bi-conformal transformation that the symmetry of the D-dimensional metric is enhanced after its application. Namely, the metric becomes a direct sum of the metric on a unit sphere and the metric of 2D anti-de Sitter space. The method of the heat kernels is used to find the Green function in this new space, which allows one, after dimensional reduction, to obtain a static Green function in the original space of the static black hole. The general useful representation of static Green functions is obtained in the Schwarzschild-Tangherlini spacetimes of arbitrary dimension. The exact explicit expressions for the static Green functions are obtained in such metrics for D<6. It is shown that in the four dimensional case the corresponding Green function coincides with the Copson solution.

Correlations in Many-Body systems from two-time Greens functions

International Nuclear Information System (INIS)

Morawetz, K.; Kohler, H.S.

2000-01-01

The Kadanoff-Baym (KB) equations are solved numerically for infinite nuclear matter. In particular we calculate correlation energies and correlation times. Approximating the Green's functions in the KB collision kernel by the free Green's functions the Levinson equation is obtained. This approximation is valid for weak interactions and/or low densities. It relates to the extended quasi-particle approximation for the spectral function. The Levinson correlation energy reduces for large times to a second order Born approximation for the energy. Comparing the Levinson, Born and KB calculations allows for an estimate of higher order spectral corrections to the correlations. (authors)

Vector Green's function algorithm for radiative transfer in plane-parallel atmosphere

Energy Technology Data Exchange (ETDEWEB)

Qin Yi [School of Physics, University of New South Wales (Australia)]. E-mail: yi.qin@csiro.au; Box, Michael A. [School of Physics, University of New South Wales (Australia)

2006-01-15

Green's function is a widely used approach for boundary value problems. In problems related to radiative transfer, Green's function has been found to be useful in land, ocean and atmosphere remote sensing. It is also a key element in higher order perturbation theory. This paper presents an explicit expression of the Green's function, in terms of the source and radiation field variables, for a plane-parallel atmosphere with either vacuum boundaries or a reflecting (BRDF) surface. Full polarization state is considered but the algorithm has been developed in such way that it can be easily reduced to solve scalar radiative transfer problems, which makes it possible to implement a single set of code for computing both the scalar and the vector Green's function.

Green-function description of dense polymeric systems

NARCIS (Netherlands)

Schoot, van der P.P.A.M.

2000-01-01

A self-consistent Green-function description of concentrated polymer solutions and dense polymeric melts is presented. The method, which applies to both uniform and nonuniform systems, is used in this work to calculate the static structure factor of a homogeneous fluid of Gaussian model chains.

Momentum-space representation of Green's functions with modified dispersion on ultrastatic space-time

International Nuclear Information System (INIS)

Rinaldi, Massimiliano

2007-01-01

We consider Green's functions associated to a scalar field propagating on a curved, ultrastatic background, in the presence of modified dispersion relations. The usual proper-time DeWitt-Schwinger procedure to obtain a series representation of Green's functions is doomed to failure because of higher order spatial derivatives in the Klein-Gordon operator. We show how to overcome this difficulty by considering a preferred frame, associated to a unit timelike vector. With respect to this frame, we can express Green's functions as an integral over all frequencies of a space-dependent function. The latter can be expanded in momentum space, as a series with geometric coefficients similar to the DeWitt-Schwinger ones. By integrating over all frequencies, we finally find the expansion of Green's function up to four derivatives of the metric tensor. The relation with the proper-time formalism is also discussed

Green's functions in Bianchi type-I spaces. Relation between Minkowski and Euclidean approaches

International Nuclear Information System (INIS)

Bukhbinder, I.L.; Kirillova, E.N.

1988-01-01

A theory is considered for a free scalar field with a conformal connection in a curved space-time with a Bianchi type-I metric. A representation is obtained for the Green's function G∼ in in in the form of an integral of a Schwinger-DeWitt kernel along a contour in a plane of complex-valued proper time. It is shown how as transition may be accomplished from Green's functions in space with the Euclidean signature to Green's functions in space with Minkowski signature and vice versa

The P(phi)2 Green's functions; asymptotic perturbation expansion

International Nuclear Information System (INIS)

Dimock, J.

1976-01-01

The real time Green's functions in the P(phi) 2 quantum field theory are infinitely differentiable functions of the coupling constant lambda up to and including lamba=0. It follows that the perturbation series are asymptotic as lambda→0 + . (Auth.)

Coulomb Green's function and image potential near a cylindrical diffuse interface

Science.gov (United States)

Xue, Changfeng; Huang, Qiongwei; Deng, Shaozhong

2015-12-01

In a preceding paper [Comput. Phys. Commun. 184 (1): 51-59, 2013], we revisited the problem of calculating Coulomb Green's function and image potential near a planar diffuse interface within which the dielectric permittivity of the inhomogeneous medium changes continuously along one Cartesian direction in a transition layer between two dissimilar dielectric materials. In the present paper, we consider a cylindrical diffuse interface within which the dielectric permittivity changes continuously along the radial direction instead. First we propose a specific cylindrical diffuse interface model, termed the quasi-harmonic diffuse interface model, that can admit analytical solution for the Green's function in terms of the modified Bessel functions. Then and more importantly we develop a robust numerical method for building Green's functions for any cylindrical diffuse interface models. The main idea of the numerical method is, after dividing a diffuse interface into multiple sublayers, to approximate the dielectric permittivity profile in each one of the sublayers by one of the quasi-harmonic functional form rather than simply by a constant value as one would normally do. Next we describe how to efficiently compute well-behaved ratios, products, and logarithmic derivatives of the modified Bessel functions so as to avoid direct evaluations of individual modified Bessel functions in our formulations. Finally we conduct numerical experiments to show the effectiveness of the quasi-harmonic diffuse interface model in overcoming the divergence of the image potential, to validate the numerical method in terms of its accuracy and convergence, and to demonstrate its capability for computing Green's functions for any cylindrical diffuse interface models.

Scalar Green's functions in an Euclidean space with a conical-type line singularity

International Nuclear Information System (INIS)

Guimaraes, M.E.X.; Linet, B.

1994-01-01

In an Euclidean space with a conical-type line singularity, we determine the Green's function for a charged massive scalar field interacting with a magnetic flux running through the line singularity. We give an integral expression of the Green's function and a local form in the neighbourhood of the point source, where it is the sum of the usual Green's function in Euclidean space and a regular term. As an application, we derive the vacuum energy-momentum tensor in the massless case for an arbitrary magnetic flux. (orig.)

Green's function approach to calculate spin injection in quantum dot

International Nuclear Information System (INIS)

Tan, S.G.; Jalil, M.B.A.; Liew, Thomas; Teo, K.L.

2006-01-01

We present a theoretical model to study spin injection (η) through a quantum dot system sandwiched by two ferromagnetic contacts. The effect of contact magnetization on η was studied using Green's function descriptions of the density of states. Green's function models have the advantages that coherent effects of temperature, electron occupation in the QD, and lead perturbation on the state wave function and hence the current can be formally included in the calculations. In addition, self-consistent treatment of current with applied electrochemical potential or lead conductivity, a necessary step which has not been considered in previous works, has also been implemented in our model

Calculation of the Green functions by the coupling constant dispersion relations

International Nuclear Information System (INIS)

Bogomalny, E.B.

1977-01-01

The discontinuities of the Green functions on the cut in the complex plane of the coupling constant are calculated by the steepest descent method. The saddle points are given by the solutions of the classical field equations at those values of the coupling constant for which the classical theory has no ground state. The Green functions at the physical values of the coupling constant are determined by dispersion relations. (Auth.)

Fermionic green function and functional determinant in QCD2

International Nuclear Information System (INIS)

Nielsen, N.K.; Rothe, K.D.; Schroer, B.

1979-01-01

We obtain a closed representation for the QCD 2 fermion determinant, euclidean Green functions and induced current in generic external fields. In the absence of zero modes the results are representable as sums over tree diagrams which as we show, can also be obtained from the original Feynman perturbation series via resummation and integration over loop variables. We also investigate the modifications due to the presence of zero modes. (orig.)

Proof of the relativistic covariance of the fermion Green function in QED

International Nuclear Information System (INIS)

Nguyen Suan Han.

1995-02-01

This paper is devoted to the calculation of the fermion Green function in QED in the framework of the Minimal Quantization Method, based on an explicit solution of the constraint equations and the gauge-invariance principle. The relativistic invariant expression for the fermion Green function which has the right analytical properties is obtained. (author). 24 refs

Green's functions through so(2,1) lie algebra in nonrelativistic quantum mechanics

International Nuclear Information System (INIS)

Boschi-Filho, H.; Vaidya, A.N.

1991-01-01

The authors discuss an algebraic technique to construct the Green's function for systems described by the noncompact so(2,1) Lie algebra. They show that this technique solves the one-dimensional linear oscillator and Coulomb potentials and also generates particular solutions for other one-dimensional potentials. Then they construct explicitly the Green's function for the three-dimensional oscillator and the three-dimensional Coulomb potential, which are generalizations of the one-dimensional cases, and the Coulomb plus an Aharanov-Bohm, potential. They discuss the dynamical algebra involved in each case and also find their wave functions and bound state spectra. Finally they introduce in each case and also find their wave functions and bound state spectra. Finally they introduce a point canonical transformation in the generators of so(2,10) Lie algebra, show that this procedure permits us to solve the one-dimensional Morse potential in addition to the previous cases, and construct its Green's function and find its energy spectrum and wave functions

Multiquark masses and wave functions through modified Green's function Monte Carlo method

International Nuclear Information System (INIS)

Kerbikov, B.O.; Polikarpov, M.I.; Shevchenko, L.V.

1987-01-01

The Modified Green's function Monte Carlo method (MGFMC) is used to calculate the masses and ground-state wave functions of multiquark systems in the potential model. The previously developed MGFMC is generalized in order to treat systems containing quarks with inequal masses. The obtained results are presented with the Cornell potential for the masses and the wave functions of light and heavy flavoured baryons and multiquark states (N=6, 9, 12) made of light quarks

How to use retarded Green's functions in de Sitter spacetime

International Nuclear Information System (INIS)

Higuchi, Atsushi; Cheong, Lee Yen

2008-01-01

We demonstrate in examples that the covariant retarded Green's functions in electromagnetism and linearized gravity work as expected in de Sitter spacetime. We first clarify how retarded Green's functions should be used in spacetimes with spacelike past infinity such as de Sitter spacetime. In particular, we remind the reader of a general formula which gives the field for given initial data on a Cauchy surface and a given source (a charge or stress-energy tensor distribution) in its future. We then apply this formula to three examples: (i) electromagnetism in the future of a Cauchy surface in Minkowski spacetime, (ii) electromagnetism in de Sitter spacetime, and (iii) linearized gravity in de Sitter spacetime. In each example the field is reproduced correctly as predicted by the general argument. In the third example we construct a linearized gravitational field from two equal point masses located at the 'North and South Poles' which is nonsingular on the cosmological horizon and satisfies a covariant gauge condition and show that this field is reproduced by the retarded Green's function with corresponding gauge parameters.

Asymptotic Green's function in homogeneous anisotropic viscoelastic media

Czech Academy of Sciences Publication Activity Database

Vavryčuk, Václav

2007-01-01

Roč. 463, č. 2086 (2007), s. 2689-2707 ISSN 1364-5021 Institutional research plan: CEZ:AV0Z30120515 Keywords : anisotropy * attenuation * Green's function * viscoelasticity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.523, year: 2007

Leading effect of visual plant characteristics for functional uses of green spaces

Directory of Open Access Journals (Sweden)

Beyza Şat Güngör

2016-07-01

Full Text Available Plant materials have the ability to lead the people’s functional use purposes with their visual characteristics. In this study, we examined whether the functional use follows the plant materials’ visual characteristics like a big size tree’s shade use. As visual characteristics of the plants; size, texture, color, and planting design basics are considered. Six urban green spaces determined for this experimental field study in the center of Kırklareli Province, and then a site survey implemented to determine apparent visual characteristics of the plants and matched functional uses with their visual characteristics. Five functional use types determined according to the visual plant characteristics (sitting and resting, pedestrian transition, meeting point, walking and recreational uses. Best representing four photos of each green space’s plant materials are used in photo questionnaires. 89 photo questionnaires were conducted. Five functional use type options indicated in the questionnaire for each green space and one of the options were coinciding with the visual plant characteristics of that green space according to the site survey results. For the analyses of questionnaires; SPSS 17 statistical packages were used. As result; the hypothesis was confirmed by coinciding statistical analyses results with the site survey results.

Nonequilibrium Green's function formulation of quantum transport theory for multi-band semiconductors

International Nuclear Information System (INIS)

Zhao, Peiji; Horing, Norman J.M.; Woolard, Dwight L.; Cui, H.L.

2003-01-01

We present a nonequilibrium Green's function formulation of many-body quantum transport theory for multi-band semiconductor systems with a phonon bath. The equations are expressed exactly in terms of single particle nonequilibrium Green's functions and self-energies, treating the open electron-hole system in weak interaction with the bath. A decoupling technique is employed to separate the individual band Green's function equations of motion from one another, with the band-band interaction effects embedded in ''cross-band'' self-energies. This nonequilibrium Green's function formulation of quantum transport theory is amenable to solution by parallel computing because of its formal decoupling with respect to inter-band interactions. Moreover, this formulation also permits coding the simulator of an n-band semiconductor in terms of that for an (n-1)-band system, in step with the current tendency and development of programming technology. Finally, the focus of these equations on individual bands provides a relatively direct route for the determination of carrier motion in energy bands, and to delineate the influence of intra- and inter-band interactions. A detailed description is provided for three-band semiconductor systems

Green`s function of Maxwell`s equations and corresponding implications for iterative methods

Energy Technology Data Exchange (ETDEWEB)

Singer, B.S. [Macquarie Univ., Sydney (Australia); Fainberg, E.B. [Inst. of Physics of the Earth, Moscow (Russian Federation)

1996-12-31

Energy conservation law imposes constraints on the norm and direction of the Hilbert space vector representing a solution of Maxwell`s equations. In this paper, we derive these constrains and discuss the corresponding implications for the Green`s function of Maxwell`s equations in a dissipative medium. It is shown that Maxwell`s equations can be reduced to an integral equation with a contracting kernel. The equation can be solved using simple iterations. Software based on this algorithm have successfully been applied to a wide range of problems dealing with high contrast models. The matrix corresponding to the integral equation has a well defined spectrum. The equation can be symmetrized and solved using different approaches, for instance one of the conjugate gradient methods.

Water hammer prediction and control: the Green's function method

Science.gov (United States)

Xuan, Li-Jun; Mao, Feng; Wu, Jie-Zhi

2012-04-01

By Green's function method we show that the water hammer (WH) can be analytically predicted for both laminar and turbulent flows (for the latter, with an eddy viscosity depending solely on the space coordinates), and thus its hazardous effect can be rationally controlled and minimized. To this end, we generalize a laminar water hammer equation of Wang et al. (J. Hydrodynamics, B2, 51, 1995) to include arbitrary initial condition and variable viscosity, and obtain its solution by Green's function method. The predicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.

Patched Green's function techniques for two-dimensional systems

DEFF Research Database (Denmark)

Settnes, Mikkel; Power, Stephen; Lin, Jun

2015-01-01

We present a numerically efficient technique to evaluate the Green's function for extended two-dimensional systems without relying on periodic boundary conditions. Different regions of interest, or “patches,” are connected using self-energy terms which encode the information of the extended parts...

Time-domain Green's Function Method for three-dimensional nonlinear subsonic flows

Science.gov (United States)

Tseng, K.; Morino, L.

1978-01-01

The Green's Function Method for linearized 3D unsteady potential flow (embedded in the computer code SOUSSA P) is extended to include the time-domain analysis as well as the nonlinear term retained in the transonic small disturbance equation. The differential-delay equations in time, as obtained by applying the Green's Function Method (in a generalized sense) and the finite-element technique to the transonic equation, are solved directly in the time domain. Comparisons are made with both linearized frequency-domain calculations and existing nonlinear results.

Frequency-domain Green's functions for radar waves in heterogeneous 2.5D media

Science.gov (United States)

Ellefsen, K.J.; Croize, D.; Mazzella, A.T.; McKenna, J.R.

2009-01-01

Green's functions for radar waves propagating in heterogeneous 2.5D media might be calculated in the frequency domain using a hybrid method. The model is defined in the Cartesian coordinate system, and its electromagnetic properties might vary in the x- and z-directions, but not in the y-direction. Wave propagation in the x- and z-directions is simulated with the finite-difference method, and wave propagation in the y-direction is simulated with an analytic function. The absorbing boundaries on the finite-difference grid are perfectly matched layers that have been modified to make them compatible with the hybrid method. The accuracy of these numerical Greens functions is assessed by comparing them with independently calculated Green's functions. For a homogeneous model, the magnitude errors range from -4.16% through 0.44%, and the phase errors range from -0.06% through 4.86%. For a layered model, the magnitude errors range from -2.60% through 2.06%, and the phase errors range from -0.49% through 2.73%. These numerical Green's functions might be used for forward modeling and full waveform inversion. ?? 2009 Society of Exploration Geophysicists. All rights reserved.

Sum-over-histories representation for the causal Green function of free scalar field theory

International Nuclear Information System (INIS)

Rudolph, O.

1993-10-01

A set of Green functions G α (x-y), α element of [0, 2π], for free scalar field theory is introduced, varying between the Hadamard Green function Δ 1 (x-y) triple bond 0vertical stroke {φ(x), φ(y)}vertical stroke 0> and the causal Green function G π (x-y)=iΔ(x-y) triple bond [φ(x), φ(y)]. For every α element of [0, 2π] a path-integral representation for G α is obtained both in the configuration space and in the phase space of the classical relativistic particle. Especially setting α=π a sum-over-histories representation for the causal Green function is obtained. Furthermore using BRST theory an alternative path-integral representation for G α is presented. From these path integral representations the composition laws for the G α 's are derived using a modified path decomposition expansion. (orig.)

Euclidean scalar Green function in a higher dimensional global monopole space-time

International Nuclear Information System (INIS)

Bezerra de Mello, E.R.

2002-01-01

We construct the explicit Euclidean scalar Green function associated with a massless field in a higher dimensional global monopole space-time, i.e., a (1+d)-space-time with d≥3 which presents a solid angle deficit. Our result is expressed in terms of an infinite sum of products of Legendre functions with Gegenbauer polynomials. Although this Green function cannot be expressed in a closed form, for the specific case where the solid angle deficit is very small, it is possible to develop the sum and obtain the Green function in a more workable expression. Having this expression it is possible to calculate the vacuum expectation value of some relevant operators. As an application of this formalism, we calculate the renormalized vacuum expectation value of the square of the scalar field, 2 (x)> Ren , and the energy-momentum tensor, μν (x)> Ren , for the global monopole space-time with spatial dimensions d=4 and d=5

Green function of a three-dimensional Wick problem

International Nuclear Information System (INIS)

Matveev, V.A.

1988-01-01

An exact solution of a three-dimensional Coulomb Wick-Cutkovsky problem has been obtained which possesses the hidden 0(4)-symmetry. Here we shell give the derivation of the corresponding Green function and consider its connection with the asymptoric behaviour of the scattering amplitude. 9 refs

High energy, high average power solid state green or UV laser

Science.gov (United States)

Hackel, Lloyd A.; Norton, Mary; Dane, C. Brent

2004-03-02

A system for producing a green or UV output beam for illuminating a large area with relatively high beam fluence. A Nd:glass laser produces a near-infrared output by means of an oscillator that generates a high quality but low power output and then multi-pass through and amplification in a zig-zag slab amplifier and wavefront correction in a phase conjugator at the midway point of the multi-pass amplification. The green or UV output is generated by means of conversion crystals that follow final propagation through the zig-zag slab amplifier.

Study on application of green's function method in thermal stress rapid calculation

International Nuclear Information System (INIS)

Zhang Guihe; Duan Yuangang; Xu Xiao; Chen Rong

2013-01-01

This paper presents a quick and accuracy thermal stress calculation method, the Green's Function Method, which is a combination of finite element method and numerical algorithm method. Thermal stress calculation of Safe Injection Nozzle of Reactor Coolant Line of PWR plant is performed with Green's function method for heatup and cooldown thermal transients as a demonstration example, and the result is compared with finite element method to verify the rationality and accuracy of this method. The advantage and disadvantage of the Green's function method and the finite element method are also compared. (authors)

Fitting a function to time-dependent ensemble averaged data.

Science.gov (United States)

Fogelmark, Karl; Lomholt, Michael A; Irbäck, Anders; Ambjörnsson, Tobias

2018-05-03

Time-dependent ensemble averages, i.e., trajectory-based averages of some observable, are of importance in many fields of science. A crucial objective when interpreting such data is to fit these averages (for instance, squared displacements) with a function and extract parameters (such as diffusion constants). A commonly overlooked challenge in such function fitting procedures is that fluctuations around mean values, by construction, exhibit temporal correlations. We show that the only available general purpose function fitting methods, correlated chi-square method and the weighted least squares method (which neglects correlation), fail at either robust parameter estimation or accurate error estimation. We remedy this by deriving a new closed-form error estimation formula for weighted least square fitting. The new formula uses the full covariance matrix, i.e., rigorously includes temporal correlations, but is free of the robustness issues, inherent to the correlated chi-square method. We demonstrate its accuracy in four examples of importance in many fields: Brownian motion, damped harmonic oscillation, fractional Brownian motion and continuous time random walks. We also successfully apply our method, weighted least squares including correlation in error estimation (WLS-ICE), to particle tracking data. The WLS-ICE method is applicable to arbitrary fit functions, and we provide a publically available WLS-ICE software.

Habitat connectivity and local conditions shape taxonomic and functional diversity of arthropods on green roofs.

Science.gov (United States)

Braaker, Sonja; Obrist, Martin Karl; Ghazoul, Jaboury; Moretti, Marco

2017-05-01

Increasing development of urban environments creates high pressure on green spaces with potential negative impacts on biodiversity and ecosystem services. There is growing evidence that green roofs - rooftops covered with vegetation - can contribute mitigate the loss of urban green spaces by providing new habitats for numerous arthropod species. Whether green roofs can contribute to enhance taxonomic and functional diversity and increase connectivity across urbanized areas remains, however, largely unknown. Furthermore, only limited information is available on how environmental conditions shape green roof arthropod communities. We investigated the community composition of arthropods (Apidae, Curculionidae, Araneae and Carabidae) on 40 green roofs and 40 green sites at ground level in the city of Zurich, Switzerland. We assessed how the site's environmental variables (such as area, height, vegetation, substrate and connectivity among sites) affect species richness and functional diversity using generalized linear models. We used an extension of co-inertia analysis (RLQ) and fourth-corner analysis to highlight the mechanism underlying community assemblages across taxonomic groups on green roof and ground communities. Species richness was higher at ground-level sites, while no difference in functional diversity was found between green roofs and ground sites. Green roof arthropod diversity increased with higher connectivity and plant species richness, irrespective of substrate depth, height and area of green roofs. The species trait analysis reviewed the mechanisms related to the environmental predictors that shape the species assemblages of the different taxa at ground and roof sites. Our study shows the important contribution of green roofs in maintaining high functional diversity of arthropod communities across different taxonomic groups, despite their lower species richness compared with ground sites. Species communities on green roofs revealed to be characterized

Green Economy Performance and Green Productivity Growth in China’s Cities: Measures and Policy Implication

Directory of Open Access Journals (Sweden)

Jianglong Li

2016-09-01

Full Text Available Resource depletion and environmental degradation have become serious challenges for China’s sustainable development. This paper constructs indicators to assess China’s green economy performance and green productivity growth, in which economic expansion, resource conservation and environmental protection need to be incorporated simultaneously. For this purpose, we combine non-radial directional distance function and meta-frontier Malmquist productivity to develop the indicators. The methodology also allows for the decomposition of driving forces of China’s green economy. Moreover, the dataset employed in this paper allows for the evaluation of 275 cities in China during the period 2003–2012. The main findings are as follows. First, most of China’s cities did not perform efficiently in terms of the green economy, with an average score of only 0.233. Second, the growth rate of green productivity is slower than real GDP, and the green productivity growth in China is only moderate. Third, innovation is the main driving force of China’s green productivity growth, but the central region lags behind when it comes to green innovation. Fourth, artificial local protectionism and transport limitations impede the progress of cities that perform ineffectively in the green economy. Based on our empirical findings, we provide policy implications and suggestions for enhancing China’s green economy performance and productivity growth.

The Euclidean scalar Green function in the five-dimensional Kaluza-Klein magnetic monopole space-time

International Nuclear Information System (INIS)

Bezerra de Mello, E.R.

2006-01-01

In this paper we present, in a integral form, the Euclidean Green function associated with a massless scalar field in the five-dimensional Kaluza-Klein magnetic monopole superposed to a global monopole, admitting a nontrivial coupling between the field with the geometry. This Green function is expressed as the sum of two contributions: the first one related with uncharged component of the field, is similar to the Green function associated with a scalar field in a four-dimensional global monopole space-time. The second contains the information of all the other components. Using this Green function it is possible to study the vacuum polarization effects on this space-time. Explicitly we calculate the renormalized vacuum expectation value * (x)Φ(x)> Ren , which by its turn is also expressed as the sum of two contributions

Sum-over-histories representation for the causal Green function of free scalar field theory

International Nuclear Information System (INIS)

Rudolph, O.

1995-01-01

A set of Green functions scrG α (x-y), α element-of[0,2π] for free scalar field theory is introduced, varying between the Hadamard Green function Δ 1 (x-y)==left-angle 0|{cphi(x),cphi(y)}|0 right-angle and the causal Green function scrG π (x-y)=iΔ(x-y)==[cphi(x),cphi(y)]. For every α element-of[0,2π] a path integral representation for scrG α is obtained both in configuration space and in the phase space of the classical relativistic particle. Setting α=π a sum-over-histories representation for the causal Green function is obtained. Furthermore, a reduced phase space integral representation for the scrG α 's is stated and an alternative BRST path integral representation for scrG α is presented. From these path integral representations the composition laws for the scrG α 's are derived using a modified path decomposition expansion

Lateral dispersion coefficients as functions of averaging time

International Nuclear Information System (INIS)

Sheih, C.M.

1980-01-01

Plume dispersion coefficients are discussed in terms of single-particle and relative diffusion, and are investigated as functions of averaging time. To demonstrate the effects of averaging time on the relative importance of various dispersion processes, and observed lateral wind velocity spectrum is used to compute the lateral dispersion coefficients of total, single-particle and relative diffusion for various averaging times and plume travel times. The results indicate that for a 1 h averaging time the dispersion coefficient of a plume can be approximated by single-particle diffusion alone for travel times <250 s and by relative diffusion for longer travel times. Furthermore, it is shown that the power-law formula suggested by Turner for relating pollutant concentrations for other averaging times to the corresponding 15 min average is applicable to the present example only when the averaging time is less than 200 s and the tral time smaller than about 300 s. Since the turbulence spectrum used in the analysis is an observed one, it is hoped that the results could represent many conditions encountered in the atmosphere. However, as the results depend on the form of turbulence spectrum, the calculations are not for deriving a set of specific criteria but for demonstrating the need in discriminating various processes in studies of plume dispersion

Brazilian Green Propolis Improves Antioxidant Function in Patients with Type 2 Diabetes Mellitus

Directory of Open Access Journals (Sweden)

Liting Zhao

2016-05-01

Full Text Available Propolis contains a variety of bioactive components and possesses many biological properties. This study was designed to evaluate potential effects of Brazilian green propolis on glucose metabolism and antioxidant function in patients with type 2 diabetes mellitus (T2DM. In the 18-week randomized controlled study, enrolled patients with T2DM were randomly assigned to Brazilian green propolis group (900 mg/day (n = 32 and control group (n = 33. At the end of the study, no significant difference was found in serum glucose, glycosylated hemoglobin, insulin, aldose reductase or adiponectin between the two groups. However, serum GSH and total polyphenols were significantly increased, and serum carbonyls and lactate dehydrogenase activity were significantly reduced in the Brazilian green propolis group. Serum TNF-α was significantly decreased, whereas serum IL-1β and IL-6 were significantly increased in the Brazilian green propolis group. It is concluded that Brazilian green propolis is effective in improving antioxidant function in T2DM patients.

Analytic and numeric Green's functions for a two-dimensional electron gas in an orthogonal magnetic field

International Nuclear Information System (INIS)

Cresti, Alessandro; Grosso, Giuseppe; Parravicini, Giuseppe Pastori

2006-01-01

We have derived closed analytic expressions for the Green's function of an electron in a two-dimensional electron gas threaded by a uniform perpendicular magnetic field, also in the presence of a uniform electric field and of a parabolic spatial confinement. A workable and powerful numerical procedure for the calculation of the Green's functions for a large infinitely extended quantum wire is considered exploiting a lattice model for the wire, the tight-binding representation for the corresponding matrix Green's function, and the Peierls phase factor in the Hamiltonian hopping matrix element to account for the magnetic field. The numerical evaluation of the Green's function has been performed by means of the decimation-renormalization method, and quite satisfactorily compared with the analytic results worked out in this paper. As an example of the versatility of the numerical and analytic tools here presented, the peculiar semilocal character of the magnetic Green's function is studied in detail because of its basic importance in determining magneto-transport properties in mesoscopic systems

Discrete state perturbation theory via Green's functions

International Nuclear Information System (INIS)

Rubinson, W.

1975-01-01

The exposition of stationary-state perturbation theory via the Green's function method in Goldberger and Watson's Collision Theory is reworked in a way that makes explicit its mathematical basis. It is stressed that the theory consists of the construction of, and manipulations on, a mathematical identity. The perturbation series fall out of the identity almost immediately. The logical status of the method is commented on

Extraction of thermal Green's function using diffuse fields: a passive approach applied to thermography

Science.gov (United States)

Capriotti, Margherita; Sternini, Simone; Lanza di Scalea, Francesco; Mariani, Stefano

2016-04-01

In the field of non-destructive evaluation, defect detection and visualization can be performed exploiting different techniques relying either on an active or a passive approach. In the following paper the passive technique is investigated due to its numerous advantages and its application to thermography is explored. In previous works, it has been shown that it is possible to reconstruct the Green's function between any pair of points of a sensing grid by using noise originated from diffuse fields in acoustic environments. The extraction of the Green's function can be achieved by cross-correlating these random recorded waves. Averaging, filtering and length of the measured signals play an important role in this process. This concept is here applied in an NDE perspective utilizing thermal fluctuations present on structural materials. Temperature variations interacting with thermal properties of the specimen allow for the characterization of the material and its health condition. The exploitation of the thermographic image resolution as a dense grid of sensors constitutes the basic idea underlying passive thermography. Particular attention will be placed on the creation of a proper diffuse thermal field, studying the number, placement and excitation signal of heat sources. Results from numerical simulations will be presented to assess the capabilities and performances of the passive thermal technique devoted to defect detection and imaging of structural components.

Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

Energy Technology Data Exchange (ETDEWEB)

Kowalski, K., E-mail: karol.kowalski@pnnl.gov; Bhaskaran-Nair, K.; Shelton, W. A. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352 (United States)

2014-09-07

In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N − 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N − 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. As a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function.

Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

Energy Technology Data Exchange (ETDEWEB)

Kowalski, K. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA; Bhaskaran-Nair, K. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA; Shelton, W. A. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA

2014-09-07

In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N - 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N - 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. Finally, as a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function.

Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

International Nuclear Information System (INIS)

Kowalski, K.; Bhaskaran-Nair, K.; Shelton, W. A.

2014-01-01

In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N − 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N − 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. As a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function

Exactly averaged equations for flow and transport in random media

International Nuclear Information System (INIS)

Shvidler, Mark; Karasaki, Kenzi

2001-01-01

It is well known that exact averaging of the equations of flow and transport in random porous media can be realized only for a small number of special, occasionally exotic, fields. On the other hand, the properties of approximate averaging methods are not yet fully understood. For example, the convergence behavior and the accuracy of truncated perturbation series. Furthermore, the calculation of the high-order perturbations is very complicated. These problems for a long time have stimulated attempts to find the answer for the question: Are there in existence some exact general and sufficiently universal forms of averaged equations? If the answer is positive, there arises the problem of the construction of these equations and analyzing them. There exist many publications related to these problems and oriented on different applications: hydrodynamics, flow and transport in porous media, theory of elasticity, acoustic and electromagnetic waves in random fields, etc. We present a method of finding the general form of exactly averaged equations for flow and transport in random fields by using (1) an assumption of the existence of Green's functions for appropriate stochastic problems, (2) some general properties of the Green's functions, and (3) the some basic information about the random fields of the conductivity, porosity and flow velocity. We present a general form of the exactly averaged non-local equations for the following cases. 1. Steady-state flow with sources in porous media with random conductivity. 2. Transient flow with sources in compressible media with random conductivity and porosity. 3. Non-reactive solute transport in random porous media. We discuss the problem of uniqueness and the properties of the non-local averaged equations, for the cases with some types of symmetry (isotropic, transversal isotropic, orthotropic) and we analyze the hypothesis of the structure non-local equations in general case of stochastically homogeneous fields. (author)

Green functions and scattering amplitudes in many-dimensional space

International Nuclear Information System (INIS)

Fabre de la Ripelle, M.

1993-01-01

Methods for solving scattering are studied in many-dimensional space. Green function and scattering amplitudes are given in terms of the required asymptotic behaviour of the wave function. The Born approximation and the optical theorem are derived in many-dimensional space. Phase-shift analyses are performed for hypercentral potentials and for non-hypercentral potentials by use of the hyperspherical adiabatic approximation. (author)

Green's functions, states and renormalisation

International Nuclear Information System (INIS)

Brown, M.R.; Ottewill, A.C.

1982-01-01

The significance that is to be attached to different operator orderings of free quantum field theories in curved space-time is examined. It is hoped thus to elucidate the renormalization of such theories. It is argued that as in flat space, these theories should be rendered finite by normal ordering with respect to a local geometrical vacuum state. Flat space is considered first, then an analogous local, geometrical Green's function for curved space-time is defined. Examples given are the Einstein static universe, the open Einstein universe and the de Sitter universe. It is observed that normalization provides some insight into the nature of vacuum stress. (U.K.)

Use of Green's functions in the numerical solution of two-point boundary value problems

Science.gov (United States)

Gallaher, L. J.; Perlin, I. E.

1974-01-01

This study investigates the use of Green's functions in the numerical solution of the two-point boundary value problem. The first part deals with the role of the Green's function in solving both linear and nonlinear second order ordinary differential equations with boundary conditions and systems of such equations. The second part describes procedures for numerical construction of Green's functions and considers briefly the conditions for their existence. Finally, there is a description of some numerical experiments using nonlinear problems for which the known existence, uniqueness or convergence theorems do not apply. Examples here include some problems in finding rendezvous orbits of the restricted three body system.

Rapid finite-fault inversions in Southern California using Cybershake Green's functions

Science.gov (United States)

Thio, H. K.; Polet, J.

2017-12-01

We have developed a system for rapid finite fault inversion for intermediate and large Southern California earthquakes using local, regional and teleseismic seismic waveforms as well as geodetic data. For modeling the local seismic data, we use 3D Green's functions from the Cybershake project, which were made available to us courtesy of the Southern California Earthquake Center (SCEC). The use of 3D Green's functions allows us to extend the inversion to higher frequency waveform data and smaller magnitude earthquakes, in addition to achieving improved solutions in general. The ultimate aim of this work is to develop the ability to provide high quality finite fault models within a few hours after any damaging earthquake in Southern California, so that they may be used as input to various post-earthquake assessment tools such as ShakeMap, as well as by the scientific community and other interested parties. Additionally, a systematic determination of finite fault models has value as a resource for scientific studies on detailed earthquake processes, such as rupture dynamics and scaling relations. We are using an established least-squares finite fault inversion method that has been applied extensively both on large as well as smaller regional earthquakes, in conjunction with the 3D Green's functions, where available, as well as 1D Green's functions for areas for which the Cybershake library has not yet been developed. We are carrying out validation and calibration of this system using significant earthquakes that have occurred in the region over the last two decades, spanning a range of locations and magnitudes (5.4 and higher).

Recent advances in the spectral green's function method for monoenergetic slab-geometry fixed-source adjoint transport problems in S{sub N} formulation

Energy Technology Data Exchange (ETDEWEB)

Curbelo, Jesus P.; Alves Filho, Hermes; Barros, Ricardo C., E-mail: jperez@iprj.uerj.br, E-mail: halves@iprj.uerj.br, E-mail: rcbarros@pq.cnpq.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico. Programa de Pos-Graduacao em Modelagem Computacional; Hernandez, Carlos R.G., E-mail: cgh@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC), La Habana (Cuba)

2015-07-01

The spectral Green's function (SGF) method is a numerical method that is free of spatial truncation errors for slab-geometry fixed-source discrete ordinates (S{sub N}) adjoint problems. The method is based on the standard spatially discretized adjoint S{sub N} balance equations and a nonstandard adjoint auxiliary equation expressing the node-average adjoint angular flux, in each discretization node, as a weighted combination of the node-edge outgoing adjoint fluxes. The auxiliary equation contains parameters which act as Green's functions for the cell-average adjoint angular flux. These parameters are determined by means of a spectral analysis which yields the local general solution of the S{sub N} equations within each node of the discretization grid. In this work a number of advances in the SGF adjoint method are presented: the method is extended to adjoint S{sub N} problems considering linearly anisotropic scattering and non-zero prescribed boundary conditions for the forward source-detector problem. Numerical results to typical model problems are considered to illustrate the efficiency and accuracy of the o offered method. (author)

The Green function in the secondary model of thermalization; La funcion de GREEN en el Modelo secundario de Termalizacion

Energy Technology Data Exchange (ETDEWEB)

Guasp, J

1972-07-01

The Green Function of the thermalization problem is studied in the secondary model case through the spatial Fourier transform. A relation between singularities and eigenvalues allows the determination of the analyticity dominion. The eigenvalue spectrum has a purely discrete part, laying on an interval of the imaginary axis of the K complex plane (the Fourier parameter), and another part, purely continuous, laying in the reminder of the imaginary axis. A correspondence between discrete eigenvalues and exponential modes of the Green Function, extemal properties for the eigenvalues and some remarkable properties of the eigenfunctions are established. (Author) 32 refs.

Green's function for a neutral particle of spin 1/2 in a magnetic field

International Nuclear Information System (INIS)

Rodrigues, Rafael de Lima; Vaidya, Arvind Narayan

2001-12-01

Using the spectral theorema in context of Green's function in momentum space of neutrons in the magnetic field of a linear conductor with current the bound state energy spectrum and eigenfunctions are deduced. It's also pointed out that this problem present a new scenary of Green's function in non-relativistic quantum mechanics. (author)

A time-dependent Green's function-based model for stream ...

African Journals Online (AJOL)

DRINIE

2003-07-03

Jul 3, 2003 ... applications, this Green's function has found use primarily in linear heat transfer and flow ... based on the mathematical description of the flow with the nonlinear .... i∂/∂x + j∂/∂y is the two-dimensional gradient operator,.

convergent methods for calculating thermodynamic Green functions

OpenAIRE

Bowen, S. P.; Williams, C. D.; Mancini, J. D.

1984-01-01

A convergent method of approximating thermodynamic Green functions is outlined briefly. The method constructs a sequence of approximants which converges independently of the strength of the Hamiltonian's coupling constants. Two new concepts associated with the approximants are introduced: the resolving power of the approximation, and conditional creation (annihilation) operators. These ideas are illustrated on an exactly soluble model and a numerical example. A convergent expression for the s...

Self-consistent green function calculations for isospin asymmetric nuclear matter

International Nuclear Information System (INIS)

Mansour, Hesham; Gad, Khalaf; Hassaneen, Khaled S.A.

2010-01-01

The one-body potentials for protons and neutrons are obtained from the self-consistent Green-function calculations of asymmetric nuclear matter, in particular their dependence on the degree of proton/neutron asymmetry. Results of the binding energy per nucleon as a function of the density and asymmetry parameter are presented for the self-consistent Green function approach using the CD-Bonn potential. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. The incompressibility for asymmetric nuclear matter has been also investigated in the framework of the self-consistent Green-function approach using the CD-Bonn potential. The behavior of the incompressibility is studied for different values of the nuclear density and the neutron excess parameter. The nuclear symmetry potential at fixed nuclear density is also calculated and its value decreases with increasing the nucleon energy. In particular, the nuclear symmetry potential at saturation density changes from positive to negative values at nucleon kinetic energy of about 200 MeV. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The proton/neutron effective mass splitting in neutron-rich matter has been studied. The predicted isospin splitting of the proton/neutron effective mass splitting in neutron-rich matter is such that m n * ≥ m p * . (author)

Applications of Green's functions in science and engineering

CERN Document Server

Greenberg, Michael D

2015-01-01

Concise and highly regarded, this treatment of Green's functions and their applications in science and engineering is geared toward undergraduate and graduate students with only a moderate background in ordinary differential equations and partial differential equations. The text also includes a wealth of information of a more general nature on boundary value problems, generalized functions, eigenfunction expansions, partial differential equations, and acoustics. The two-part treatment begins with an overview of applications to ordinary differential equations. Topics include the adjoint operato

Green function and scattering amplitudes in many dimensional space

International Nuclear Information System (INIS)

Fabre de la Ripelle, M.

1991-06-01

Methods for solving scattering are studied in many dimensional space. Green function and scattering amplitudes are given in terms of the requested asymptotic behaviour of the wave function. The Born approximation and the optical theorem are derived in many dimensional space. Phase-shift analysis are developed for hypercentral potentials and for non-hypercentral potentials with the hyperspherical adiabatic approximation. (author) 16 refs., 3 figs

The effects of the Green House nursing home model on ADL function trajectory: A retrospective longitudinal study.

Science.gov (United States)

Yoon, Ju Young; Brown, Roger L; Bowers, Barbara J; Sharkey, Siobhan S; Horn, Susan D

2016-01-01

Growing attention in the past few decades has focused on improving care quality and quality of life for nursing home residents. Many traditional nursing homes have attempted to transform themselves to become more homelike emphasizing individualized care. This trend is referred to as nursing home culture change in the U.S. A promising culture change nursing home model, the Green House nursing home model, has shown positive psychological outcomes. However, little is known about whether the Green House nursing home model has positive effects on physical function compared to traditional nursing homes. To examine the longitudinal effects of the Green House nursing home model by comparing change patterns of activities of daily living function over time between Green House home residents and traditional nursing home residents. A retrospective longitudinal study. Four Green House organizations (nine Green House units and four traditional units). A total of 242 residents (93 Green House residents and 149 traditional home residents) who had stayed in the nursing home at least 6 months from admission. The outcome was activities of daily living function, and the main independent variable was the facility type in which the resident stayed: a Green House or traditional unit. Age, gender, comorbidity score, cognitive function, and depressive symptoms at baseline were controlled. All of these measures were from a minimum dataset. Growth curve modeling and growth mixture modeling were employed in this study for longitudinal analyses. The mean activities of daily living function showed deterioration over time, and the rates of deterioration between Green House and traditional home residents were not different over time. Four different activities of daily living function trajectories were identified for 18 months, but there was no statistical difference in the likelihood of being in one of the four trajectory classes between the two groups. Although Green House nursing homes are

Bio-templated CdSe quantum dots green synthesis in the functional protein, lysozyme, and biological activity investigation

International Nuclear Information System (INIS)

Wang, Qisui; Li, Song; Liu, Peng; Min, Xinmin

2012-01-01

Bifunctional fluorescence (CdSe Quantum Dots) – protein (Lysozyme) nanocomposites were synthesized at room temperature by a protein-directed, solution-phase, green-synthetic method. Fluorescence (FL) and absorption spectra showed that CdSe QDs were prepared successfully with Lyz. The average particle size and crystalline structure of QDs were investigated by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD), respectively. With attenuated total reflection-fourier transform infrared (ATR-FTIR) spectra and thermogravimetric (TG) analysis, it was confirmed that there is interaction between QDs and amide I, amide II groups in Lyz. FL polarization was measured and FL imaging was done to monitor whether QDs could be responsible for possible changes in the conformation and activity of Lyz. Interestingly, the results showed Lyz still retain the biological activity after formation of QDs, but the secondary structure of the Lyz was changed. And the advantage of this synthesis method is producing excellent fluorescent QDs with specifically biological function. -- Highlights: ► Lysozyme-directed green synthesis of CdSe quantum dots. ► Lysozyme still retain the biological activity after formation of CdSe. ► The method is the production of fluorescent QDs with highly specific and functions.

On Green's function retrieval by iterative substitution of the coupled Marchenko equations

Science.gov (United States)

van der Neut, Joost; Vasconcelos, Ivan; Wapenaar, Kees

2015-11-01

Iterative substitution of the coupled Marchenko equations is a novel methodology to retrieve the Green's functions from a source or receiver array at an acquisition surface to an arbitrary location in an acoustic medium. The methodology requires as input the single-sided reflection response at the acquisition surface and an initial focusing function, being the time-reversed direct wavefield from the acquisition surface to a specified location in the subsurface. We express the iterative scheme that is applied by this methodology explicitly as the successive actions of various linear operators, acting on an initial focusing function. These operators involve multidimensional crosscorrelations with the reflection data and truncations in time. We offer physical interpretations of the multidimensional crosscorrelations by subtracting traveltimes along common ray paths at the stationary points of the underlying integrals. This provides a clear understanding of how individual events are retrieved by the scheme. Our interpretation also exposes some of the scheme's limitations in terms of what can be retrieved in case of a finite recording aperture. Green's function retrieval is only successful if the relevant stationary points are sampled. As a consequence, internal multiples can only be retrieved at a subsurface location with a particular ray parameter if this location is illuminated by the direct wavefield with this specific ray parameter. Several assumptions are required to solve the Marchenko equations. We show that these assumptions are not always satisfied in arbitrary heterogeneous media, which can result in incomplete Green's function retrieval and the emergence of artefacts. Despite these limitations, accurate Green's functions can often be retrieved by the iterative scheme, which is highly relevant for seismic imaging and inversion of internal multiple reflections.

A single-sided representation for the homogeneous Green's function of a unified scalar wave equation.

Science.gov (United States)

Wapenaar, Kees

2017-06-01

A unified scalar wave equation is formulated, which covers three-dimensional (3D) acoustic waves, 2D horizontally-polarised shear waves, 2D transverse-electric EM waves, 2D transverse-magnetic EM waves, 3D quantum-mechanical waves and 2D flexural waves. The homogeneous Green's function of this wave equation is a combination of the causal Green's function and its time-reversal, such that their singularities at the source position cancel each other. A classical representation expresses this homogeneous Green's function as a closed boundary integral. This representation finds applications in holographic imaging, time-reversed wave propagation and Green's function retrieval by cross correlation. The main drawback of the classical representation in those applications is that it requires access to a closed boundary around the medium of interest, whereas in many practical situations the medium can be accessed from one side only. Therefore, a single-sided representation is derived for the homogeneous Green's function of the unified scalar wave equation. Like the classical representation, this single-sided representation fully accounts for multiple scattering. The single-sided representation has the same applications as the classical representation, but unlike the classical representation it is applicable in situations where the medium of interest is accessible from one side only.

Summable chains of instantons: Green's functions and the Prasad-Sommerfield limit

International Nuclear Information System (INIS)

Boutaleb-Joutei, H.; Chakrabarti, A.; Comtet, A.

1981-01-01

We construct, for each homotopy class, a type of instanton configuration which exhibits many special, simple properties. The basic reason behind such properties is indicated by deriving our configuration in the 't Hooft gauge, starting from a class of particularly simple, static, and self-dual solutions in de Sitter space. Apart from this we consider, in this paper, mostly results for flat Euclidean space. We show that the static solutions are equivalent to multiply charged instantons at the origin in Witten's sense. Green's functions for this class of instanton background are studied. The known flat-space results of Brown et al. are shown to be reducible, for our case, to totally explicit and relatively compact forms. The sums over different indices arising in their formalism are performed. The inversion of a matrix, necessary for the isospin-1 massless scalar field, is carried out explicitly, for our configuration, for arbitrary index of the background instanton field. Green's functions for the Prasad-Sommerfield case are obtained as limits of our results directly in summed-up forms. Green's functions are studied also in de Sitter space. Special features due to periodic time are pointed out

Relativistic Green function for atomic and molecular systems

Energy Technology Data Exchange (ETDEWEB)

Gruzdev, P.F.; Sherstyuk, A.I.

1981-12-01

The problem on Green function construction of Dirac equation is solved for a wide class of single electron potentials in the atom and molecule theory. The solution is obtained in the form of a spectrum analysis according to the total system of eigenfuctions of the generalized Dirac problem for eigenvalues. The problem possesses a purely discrete spectrum.

Non-equilibrium Green function method: theory and application in simulation of nanometer electronic devices

International Nuclear Information System (INIS)

Do, Van-Nam

2014-01-01

We review fundamental aspects of the non-equilibrium Green function method in the simulation of nanometer electronic devices. The method is implemented into our recently developed computer package OPEDEVS to investigate transport properties of electrons in nano-scale devices and low-dimensional materials. Concretely, we present the definition of the four real-time Green functions, the retarded, advanced, lesser and greater functions. Basic relations among these functions and their equations of motion are also presented in detail as the basis for the performance of analytical and numerical calculations. In particular, we review in detail two recursive algorithms, which are implemented in OPEDEVS to solve the Green functions defined in finite-size opened systems and in the surface layer of semi-infinite homogeneous ones. Operation of the package is then illustrated through the simulation of the transport characteristics of a typical semiconductor device structure, the resonant tunneling diodes. (review)

Green's functions of the induction equation on regions with boundary. 1

International Nuclear Information System (INIS)

Braeuer, H.J.; Raedler, K.H.

1986-01-01

The evolution of a magnetic field is considered which pervades an electrically conducting fluid and its non-conducting surroundings under the influence of electromotive forces due to internal motion and other causes. The governing equations - among which the induction equation of magnetohydrodynamics is the most prominent - pose an initial value problem for the magnetic flux density. Properties of this initial value problem and of the solving Green's function are reviewed and a general construction principle for the Green's function is given. Detailed treatment of cases where the fluid occupies a sphere or an evenly bounded half-space are presented in two subsequent papers. (author)

Electromagnetically induced nuclear beta decay calculated by a Green's function method

International Nuclear Information System (INIS)

Reiss, H.R.

1984-01-01

The transition probability for enhancement of forbidden nuclear beta decay by an applied plane-wave electromagnetic field is calculated in a nonrelativistic spinless approximation by a Green's function method. The calculation involves a stationary-phase approximation. The stationary phase points in the presence of an intense field are located in very different positions than they are in the field-free case. In order-of-magnitude terms, the results are completely consistent with an earlier, much more complete wave-function calculation which includes spin and relativistic effects. Both the present Green's function calculation and the earlier wave function calculation give electromagnetic contributions in first-forbidden nuclear beta decay matrix elements which are of order (R 0 /lambda-dash-bar/sub C/) 2 with respect to allowed decays, where R 0 is the nuclear radius and lambda-dash-bar/sub C/ is the electron Compton wavelength

Relativistic dynamics, Green function and pseudodifferential operators

Energy Technology Data Exchange (ETDEWEB)

Cirilo-Lombardo, Diego Julio [National Institute of Plasma Physics (INFIP), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires 1428 (Argentina); Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

2016-06-15

The central role played by pseudodifferential operators in relativistic dynamics is known very well. In this work, operators like the Schrodinger one (e.g., square root) are treated from the point of view of the non-local pseudodifferential Green functions. Starting from the explicit construction of the Green (semigroup) theoretical kernel, a theorem linking the integrability conditions and their dependence on the spacetime dimensions is given. Relativistic wave equations with arbitrary spin and the causality problem are discussed with the algebraic interpretation of the radical operator and their relation with coherent and squeezed states. Also we perform by means of pure theoretical procedures (based in physical concepts and symmetry) the relativistic position operator which satisfies the conditions of integrability: it is a non-local, Lorentz invariant and does not have the same problems as the “local”position operator proposed by Newton and Wigner. Physical examples, as zitterbewegung and rogue waves, are presented and deeply analyzed in this theoretical framework.

Evaluating green infrastructure in urban environments using a multi-taxa and functional diversity approach.

Science.gov (United States)

Pinho, Pedro; Correia, Otília; Lecoq, Miguel; Munzi, Silvana; Vasconcelos, Sasha; Gonçalves, Paula; Rebelo, Rui; Antunes, Cristina; Silva, Patrícia; Freitas, Catarina; Lopes, Nuno; Santos-Reis, Margarida; Branquinho, Cristina

2016-05-01

Forested areas within cities host a large number of species, responsible for many ecosystem services in urban areas. The biodiversity in these areas is influenced by human disturbances such as atmospheric pollution and urban heat island effect. To ameliorate the effects of these factors, an increase in urban green areas is often considered sufficient. However, this approach assumes that all types of green cover have the same importance for species. Our aim was to show that not all forested green areas are equal in importance for species, but that based on a multi-taxa and functional diversity approach it is possible to value green infrastructure in urban environments. After evaluating the diversity of lichens, butterflies and other-arthropods, birds and mammals in 31 Mediterranean urban forests in south-west Europe (Almada, Portugal), bird and lichen functional groups responsive to urbanization were found. A community shift (tolerant species replacing sensitive ones) along the urbanization gradient was found, and this must be considered when using these groups as indicators of the effect of urbanization. Bird and lichen functional groups were then analyzed together with the characteristics of the forests and their surroundings. Our results showed that, contrary to previous assumptions, vegetation density and more importantly the amount of urban areas around the forest (matrix), are more important for biodiversity than forest quantity alone. This indicated that not all types of forested green areas have the same importance for biodiversity. An index of forest functional diversity was then calculated for all sampled forests of the area. This could help decision-makers to improve the management of urban green infrastructures with the goal of increasing functionality and ultimately ecosystem services in urban areas. Copyright © 2016 Elsevier Inc. All rights reserved.

Vibrations in force-and-mass disordered alloys in the average local-information transfer approximation. Application to Al-Ag

International Nuclear Information System (INIS)

Czachor, A.

1979-01-01

The configuration-averaged displacement-displacement Green's function, derived in the locator-based approximation accounting for average transfer of information on local coupling and mass, has been applied to study the force-and-mass-disorder induced modifications of phonon dispersion relations in substitutional alloys of cubic structures. In this approach the translational invariance condition is obeyed whereas damping is neglected. The force-disorder was found to lead to additional splitting of phonon curves besides that due to mass-disorder, even in the small impurity-concentration case; at larger concentrations the number of splits (frequency gaps) should be still greater. The use of a quasi-locator in the Green's function derivation allows one to partly reconcile the present results with those of the average t-matrix approximation. The experimentally observed splitting in the [100]T phonon dispersion curve for Al-Ag alloys has been interpreted in terms of the above theory and of a quasi-mass of heavy impurity atoms. (Author)

A review of Green's function methods in computational fluid mechanics: Background, recent developments and future directions

International Nuclear Information System (INIS)

Dorning, J.

1981-01-01

The research and development over the past eight years on local Green's function methods for the high-accuracy, high-efficiency numerical solution of nuclear engineering problems is reviewed. The basic concepts and key ideas are presented by starting with an expository review of the original fully two-dimensional local Green's function methods developed for neutron diffusion and heat conduction, and continuing through the progressively more complicated and more efficient nodal Green's function methods for neutron diffusion, heat conduction and neutron transport to establish the background for the recent development of Green's function methods in computational fluid mechanics. Some of the impressive numerical results obtained via these classes of methods for nuclear engineering problems are briefly summarized. Finally, speculations are proffered on future directions in which the development of these types of methods in fluid mechanics and other areas might lead. (orig.) [de

Quantum thermodynamics: a nonequilibrium Green's function approach.

Science.gov (United States)

Esposito, Massimiliano; Ochoa, Maicol A; Galperin, Michael

2015-02-27

We establish the foundations of a nonequilibrium theory of quantum thermodynamics for noninteracting open quantum systems strongly coupled to their reservoirs within the framework of the nonequilibrium Green's functions. The energy of the system and its coupling to the reservoirs are controlled by a slow external time-dependent force treated to first order beyond the quasistatic limit. We derive the four basic laws of thermodynamics and characterize reversible transformations. Stochastic thermodynamics is recovered in the weak coupling limit.

Band-limited Green's Functions for Quantitative Evaluation of Acoustic Emission Using the Finite Element Method

Science.gov (United States)

Leser, William P.; Yuan, Fuh-Gwo; Leser, William P.

2013-01-01

A method of numerically estimating dynamic Green's functions using the finite element method is proposed. These Green's functions are accurate in a limited frequency range dependent on the mesh size used to generate them. This range can often match or exceed the frequency sensitivity of the traditional acoustic emission sensors. An algorithm is also developed to characterize an acoustic emission source by obtaining information about its strength and temporal dependence. This information can then be used to reproduce the source in a finite element model for further analysis. Numerical examples are presented that demonstrate the ability of the band-limited Green's functions approach to determine the moment tensor coefficients of several reference signals to within seven percent, as well as accurately reproduce the source-time function.

Simulations of Coulomb systems confined by polarizable surfaces using periodic Green functions.

Science.gov (United States)

Dos Santos, Alexandre P; Girotto, Matheus; Levin, Yan

2017-11-14

We present an efficient approach for simulating Coulomb systems confined by planar polarizable surfaces. The method is based on the solution of the Poisson equation using periodic Green functions. It is shown that the electrostatic energy arising from the surface polarization can be decoupled from the energy due to the direct Coulomb interaction between the ions. This allows us to combine an efficient Ewald summation method, or any other fast method for summing over the replicas, with the polarization contribution calculated using Green function techniques. We apply the method to calculate density profiles of ions confined between the charged dielectric and metal surfaces.

Improved quasi-static nodal green's function method

International Nuclear Information System (INIS)

Li Junli; Jing Xingqing; Hu Dapu

1997-01-01

Improved Quasi-Static Green's Function Method (IQS/NGFM) is presented, as an new kinetic method. To solve the three-dimensional transient problem, improved Quasi-Static Method is adopted to deal with the temporal problem, which will increase the time step as long as possible so as to decrease the number of times of space calculation. The time step of IQS/NGFM can be increased to 5∼10 times longer than that of Full Implicit Differential Method. In spatial calculation, the NGFM is used to get the distribution of shape function, and it's spatial mesh can be nearly 20 times larger than that of Definite Differential Method. So the IQS/NGFM is considered as an efficient kinetic method

Estimation and Simulation of Inter-station Green's Functions in the Beppu-Bay Area, Oita Prefecture, Southwest Japan: the Effect of Sedimentary Basin

Science.gov (United States)

Hayashida, T.; Yoshimi, M.; Komatsu, M.; Takenaka, H.

2017-12-01

Continuous long-term observations of ambient noise (microseisms) were performed from August 2014 to February 2017 in the Beppu-Bay area, Oita prefecture, to investigate S-wave velocity structure of deep sedimentary basin (Hayashida et al., 2015SSJ; Yoshimi and Hayashida, 2017WCEE). The observation array consists of 12 broadband stations with an average spacing of 12 km. We applied the seismic interferometry technique to the ambient noise data and derived nine-component ambient noise cross-correlation functions (Z-R, Z-T, Z-Z, R-R, R-T, R-Z, T-R, T-T, and T-Z components) between 66 pairs of stations (distance of 6.4 km to 65.2 km). We assumed the stacked cross-correlation functions as "observed Green's functions" between two stations and estimated group velocities of Rayleigh and Love waves in the frequency between 0.2 and 0.5 Hz (Hayashida et al., 2017AGU-JpGU). Theoretical Green's functions for all stations pairs were also calculated using the finite difference method (HOT-FDM, Nakamura et al., 2012BSSA), with an existing three-dimensional basin structure model (J-SHIS V2) with land and seafloor topography and a seawater layer (Okunaka et al., 2016JpGU) and a newly constructed basin structure model of the target area (Yoshimi et al., 2017AGU). The comparisons between observed and simulated Green's functions generally show good agreements in the frequency range between 0.2 and 0.5 Hz. On the other hand, both observed and simulated Green's functions for some station pairs whose traverse lines run across the deeper part of the sedimentary basin (> 2000 m) show prominent later phases that might be generated and propagated inside the basin. This indicates that the understanding of the phase generation and propagation processes can be a key factor to validate the basin structure model and we investigated the characteristics of the later phases, such as its particle motions and arrival times, using observed and simulated Green's functions in detail. Acknowledgements

From green architecture to architectural green

DEFF Research Database (Denmark)

Earon, Ofri

2011-01-01

that describes the architectural exclusivity of this particular architecture genre. The adjective green expresses architectural qualities differentiating green architecture from none-green architecture. Currently, adding trees and vegetation to the building’s facade is the main architectural characteristics...... they have overshadowed the architectural potential of green architecture. The paper questions how a green space should perform, look like and function. Two examples are chosen to demonstrate thorough integrations between green and space. The examples are public buildings categorized as pavilions. One......The paper investigates the topic of green architecture from an architectural point of view and not an energy point of view. The purpose of the paper is to establish a debate about the architectural language and spatial characteristics of green architecture. In this light, green becomes an adjective...

Connected Green function approach to symmetry breaking in Φ1+14-theory

International Nuclear Information System (INIS)

Haeuser, J.M.; Cassing, W.; Peter, A.; Thoma, M.H.

1995-01-01

Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than 4 th order for the λΦ 4 -theory in 1+1 dimensions. We apply the equations to the investigation of spontaneous symmetry breaking, i.e. to the evaluation of the effective potential at temperature T=0. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of λ crit /4m 2 =2.446 ascompared to a first order phase transition and λ crit /4m 2 =2.568 from the Gaussian effective potential approach. (orig.)

Green's function of an infinite slot printed between two homogeneous dielectrics - Part II: Uniform asymptotic solution

NARCIS (Netherlands)

Maci, S.; Neto, A.

2004-01-01

This second part of a two-paper sequence deals with the uniform asymptotic description of the Green's function of an infinite slot printed between two different homogeneous dielectric media. Starting from the magnetic current derived in Part I, the dyadic green's function is first formulated in

Analytical Methods for Malachite Green : Completion Report : Malachite Green Analysis in Water.

Energy Technology Data Exchange (ETDEWEB)

Allen, John L.; Gofus, Jane E.; Meinertz, Jeffery R.

1991-06-01

Malachite green is a known teratogen and therefore its use is limited to nonfood fish under an Investigational New Animal Drug permit (INAD), number 2573. Although a charcoal adsorption column was developed to remove malachite green from hatchery water, INAD compliance requires that the malachite green residue concentrations in any effluent from hatcheries using the chemical be quantified. Therefore, we developed a method for the analysis of malachite green residues in water. Enrichment of the residues of malachite green in water on a diol column followed by High Performance Liquid Chromatographic (HPLC) analysis gives a minimum sensitivity of less than 10 ppb for the chemical. When combined with post-column oxidation using a lead oxide post-column reactor, the procedure can be used for the simultaneous analysis of malachite green in its leuco form, a decomposition product of the dye, as well as its chromatic form. Recovery of the leuco form is pH dependent and water samples should be adjusted to pH 6 to optimize recovery of this form. Water samples spiked with malachite green were concentrated on a diol column followed by elution with 0.05 M p-toluene sulfonic acid in methanol. The methanol elutes were analyzed by HPLC. Pond water samples spiked with malachite green and leuco malachite green yielded average recoveries of 95.4% for malachite green and 57.3% for leuco malachite green. Tap water samples spiked with the carbinol form of malachite green gave average recoveries of 98.6%. The method is very sensitive and is capable of detecting malachite green residues in water at less than 10 ppb. Fish culturists, who cannot find an effective replacement for malachite green, can utilize the method to ensure that their effluents comply with INAD regulations. 13 refs., 2 figs., 7 tabs.

A Floquet-Green's function approach to mesoscopic transport under ac bias

International Nuclear Information System (INIS)

Wu, B H; Cao, J C

2008-01-01

The current response of a mesoscopic system under a periodic ac bias is investigated by combining the Floquet theorem and the nonequilibrium Green's function method. The band structure of the lead under ac bias is fully taken into account by using appropriate self-energies in an enlarged Floquet space. Both the retarded and lesser Green's functions are obtained in the Floquet basis to account for the interference and interaction effects. In addition to the external ac bias, the time-varying Coulomb interaction, which is treated at the self-consistent Hartree-Fock level, provides another internal ac field. The numerical results show that the time-varying Coulomb field yields decoherence and reduces the ringing behavior of the current response to a harmonic bias

Influence of contrast morphogenetic features of urban constructed soils on the functioning of Moscow green lawn urban ecosystems: analysis based on the field model experiment

Science.gov (United States)

Epikhina, Anna; Vizirskaya, Mariya; Mazirov, Ilya; Vasenev, Vyacheslav; Vasenev, Ivan; Valentini, Riccardo

2014-05-01

sand-soil (SS)) with three version of the depths (5, 10 and 20 cm). Soil construction with 10 cm organic horizon from TS top soil was taken as a reference. Grass mixture used for the green lawn including: Lolium perenne, Poa pratensis and Festuca rubra. For all the containers we measured soil CO2 emission by Li-820, soil temperature and moisture and the grass ornamental quality based on the 30-score scale (Laptev; 1988). All the measurements have been done in June-October 2013 with two-week time steps. We also observed the dynamic in soil chemical features (Corg, Ntot and pHKCl) monthly. We found high seasonal dynamics for all the observed functioning parameters. The highest CO2 emission was obtained in the beginning of July, whereas the lowest one - at the end of August. Maximal averaged CO2 emission was shown for the TSa and TSo substrates with the 20 cm depth. The lowest flux has been fixed for the more mineralized substrat. Soil moisture was shown as the main driving factor influencing CO2 emission both for the seasonal dynamics and for the averaged values for different substrates and depths (r=0.5, p0.05). This outcome highlights that the standards of urban constructed soils' optimal features should be the compromise between the beauty of the green lawn and climate mitigation demands. Supported by the RF governmental grant 11.G34.31.0079

Green's functions for a graphene sheet and quantum dot in a normal magnetic field

International Nuclear Information System (INIS)

Horing, Norman J Morgenstern; Liu, S Y

2009-01-01

This paper is concerned with the derivation of the retarded Green's function for a two-dimensional graphene layer in a perpendicular magnetic field in two explicit, analytic forms, which we employ in obtaining a closed-form solution for the Green's function of a tightly confined magnetized graphene quantum dot. The dot is represented by a δ (2) (r)-potential well and the system is subject to Landau quantization in the normal magnetic field

Green's functions and trace formulas for generalized Sturm-Liouville problems related by Darboux transformations

International Nuclear Information System (INIS)

Schulze-Halberg, Axel

2010-01-01

We study Green's functions of the generalized Sturm-Liouville problems that are related to each other by Darboux -equivalently, supersymmetrical - transformations. We establish an explicit relation between the corresponding Green's functions and derive a simple formula for their trace. The class of equations considered here includes the conventional Schroedinger equation and generalizations, such as for position-dependent mass and with linearly energy-dependent potential, as well as the stationary Fokker-Planck equation.

On the infrared behaviour of Yang-Mills Greens functions

International Nuclear Information System (INIS)

Olesen, P.

1976-01-01

Making certain assumptions (valid to any finite order of perturbation theory), it is shown that non-perturbatively pure Yang-Mills Greens functions are power behaved in the momenta in a limit related to the infrared limit. It is also shown that the fundamental vertices have a more singular behaviour than indicated by perturbation theory. (Auth.)

Mehler's formulae for isotropic harmonic oscillator wave functions and application in the Green function calculus

International Nuclear Information System (INIS)

Caetano Neto, E.S.

1976-01-01

A stationary Green function is calculated for the Schroedinger Hamiltonian of the multidimensional isotropic harmonic oscillator and for physical systems, which may, somehow, have their Hamiltonian reduced to one in the form of a harmonic oscillator, for any dimension [pt

Green Imidazolium Ionics-From Truly Sustainable Reagents to Highly Functional Ionic Liquids.

Science.gov (United States)

Tröger-Müller, Steffen; Brandt, Jessica; Antonietti, Markus; Liedel, Clemens

2017-09-04

We report the synthesis of task-specific imidazolium ionic compounds and ionic liquids with key functionalities of organic molecules from electro-, polymer-, and coordination chemistry. Such products are highly functional and potentially suitable for technology applications even though they are formed without elaborate reactions and from cheap and potentially green reagents. We further demonstrate the versatility of the used synthetic approach by introducing different functional and green counterions to the formed ionic liquids directly during the synthesis or after metathesis reactions. The influence of different cation structures and different anions on the thermal and electrochemical properties of the resulting ionic liquids is discussed. Our goal is to make progress towards economically competitive and sustainable task-specific ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mass corrections to Green functions in instanton vacuum model

International Nuclear Information System (INIS)

Esaibegyan, S.V.; Tamaryan, S.N.

1987-01-01

The first nonvanishing mass corrections to the effective Green functions are calculated in the model of instanton-based vacuum consisting of a superposition of instanton-antiinstanton fluctuations. The meson current correlators are calculated with account of these corrections; the mass spectrum of pseudoscalar octet as well as the value of the kaon axial constant are found. 7 refs

Existence of Green's functions in perturbative Q.E.D

International Nuclear Information System (INIS)

Seneor, R.

1976-01-01

A report is made on some work done in collaboration with P. Blanchard which shows how, in the framework developped by H.Epstein and V.Glaser, one can prove the existence of Green's functions in quantum electrodynamics (Q.E.D.). The proof can be extended, in principle, to any theory involving massive and non massive particles. (Auth.)

Analytic properties for the honeycomb lattice Green function at the origin

Science.gov (United States)

Joyce, G. S.

2018-05-01

The analytic properties of the honeycomb lattice Green function are investigated, where is a complex variable which lies in a plane. This double integral defines a single-valued analytic function provided that a cut is made along the real axis from w  =  ‑3 to . In order to analyse the behaviour of along the edges of the cut it is convenient to define the limit function where . It is shown that and can be evaluated exactly for all in terms of various hypergeometric functions, where the argument function is always real-valued and rational. The second-order linear Fuchsian differential equation satisfied by is also used to derive series expansions for and which are valid in the neighbourhood of the regular singular points and . Integral representations are established for and , where with . In particular, it is proved that where J 0(z) and Y 0(z) denote Bessel functions of the first and second kind, respectively. The results derived in the paper are utilized to evaluate the associated logarithmic integral where w lies in the cut plane. A new set of orthogonal polynomials which are connected with the honeycomb lattice Green function are also briefly discussed. Finally, a link between and the theory of Pearson random walks in a plane is established.

Casimir energies in M4≥/sup N/ for even N. Green's-function and zeta-function techniques

International Nuclear Information System (INIS)

Kantowski, R.; Milton, K.A.

1987-01-01

The Green's-function technique developed in the first paper in this series is generalized to apply to massive scalar, vector, second-order tensor, and Dirac spinor fields, as a preliminary to a full graviton calculation. The Casimir energies are of the form u/sub Casimir/ = (1/a 4 )[α/sub N/lna/b)+β/sub N/], where N (even) is the dimension of the internal sphere, a is its radius, and b/sup -1/ is an ultraviolet cutoff (presumably at the Planck scale). The coefficient of the divergent logarithm, α/sub N/, is unambiguously obtained for each field considered. The Green's-function technique gives rise to no difficulties in the evaluation of imaginary-mass-mode contributions to the Casimir energy. In addition, a new, simplified zeta-function technique is presented which is very easily implemented by symbolic programs, and which, of course, gives the same results. An error in a previous zeta-function calculation of the Casimir energy for even N is pointed out

Quantum statistical field theory an introduction to Schwinger's variational method with Green's function nanoapplications, graphene and superconductivity

CERN Document Server

Morgenstern Horing, Norman J

2017-01-01

This book provides an introduction to the methods of coupled quantum statistical field theory and Green's functions. The methods of coupled quantum field theory have played a major role in the extensive development of nonrelativistic quantum many-particle theory and condensed matter physics. This introduction to the subject is intended to facilitate delivery of the material in an easily digestible form to advanced undergraduate physics majors at a relatively early stage of their scientific development. The main mechanism to accomplish this is the early introduction of variational calculus and the Schwinger Action Principle, accompanied by Green's functions. Important achievements of the theory in condensed matter and quantum statistical physics are reviewed in detail to help develop research capability. These include the derivation of coupled field Green's function equations-of-motion for a model electron-hole-phonon system, extensive discussions of retarded, thermodynamic and nonequilibrium Green's functions...

Step-by-Step Simulation of Radiation Chemistry Using Green Functions for Diffusion-Influenced Reactions

Science.gov (United States)

Plante, Ianik; Cucinotta, Francis A.

2011-01-01

Radiolytic species are formed approximately 1 ps after the passage of ionizing radiation through matter. After their formation, they diffuse and chemically react with other radiolytic species and neighboring biological molecules, leading to various oxidative damage. Therefore, the simulation of radiation chemistry is of considerable importance to understand how radiolytic species damage biological molecules [1]. The step-by-step simulation of chemical reactions is difficult, because the radiolytic species are distributed non-homogeneously in the medium. Consequently, computational approaches based on Green functions for diffusion-influenced reactions should be used [2]. Recently, Green functions for more complex type of reactions have been published [3-4]. We have developed exact random variate generators of these Green functions [5], which will allow us to use them in radiation chemistry codes. Moreover, simulating chemistry using the Green functions is which is computationally very demanding, because the probabilities of reactions between each pair of particles should be evaluated at each timestep [2]. This kind of problem is well adapted for General Purpose Graphic Processing Units (GPGPU), which can handle a large number of similar calculations simultaneously. These new developments will allow us to include more complex reactions in chemistry codes, and to improve the calculation time. This code should be of importance to link radiation track structure simulations and DNA damage models.

Green Polymer Chemistry: Enzyme Catalysis for Polymer Functionalization

Directory of Open Access Journals (Sweden)

Sanghamitra Sen

2015-05-01

Full Text Available Enzyme catalyzed reactions are green alternative approaches to functionalize polymers compared to conventional methods. This technique is especially advantageous due to the high selectivity, high efficiency, milder reaction conditions, and recyclability of enzymes. Selected reactions can be conducted under solventless conditions without the application of metal catalysts. Hence this process is becoming more recognized in the arena of biomedical applications, as the toxicity created by solvents and metal catalyst residues can be completely avoided. In this review we will discuss fundamental aspects of chemical reactions biocatalyzed by Candida antarctica lipase B, and their application to create new functionalized polymers, including the regio- and chemoselectivity of the reactions.

Green polymer chemistry: enzyme catalysis for polymer functionalization.

Science.gov (United States)

Sen, Sanghamitra; Puskas, Judit E

2015-05-21

Enzyme catalyzed reactions are green alternative approaches to functionalize polymers compared to conventional methods. This technique is especially advantageous due to the high selectivity, high efficiency, milder reaction conditions, and recyclability of enzymes. Selected reactions can be conducted under solventless conditions without the application of metal catalysts. Hence this process is becoming more recognized in the arena of biomedical applications, as the toxicity created by solvents and metal catalyst residues can be completely avoided. In this review we will discuss fundamental aspects of chemical reactions biocatalyzed by Candida antarctica lipase B, and their application to create new functionalized polymers, including the regio- and chemoselectivity of the reactions.

Green lights

DEFF Research Database (Denmark)

Fisker, Peter Kielberg

This study investigates the effect of drought on economic activity globally using remote sensing data. In particular, predicted variation in greenness is correlated with changes in the density of artificial light observed at night on a grid of 0.25 degree latitude-longitude pixels. I define drought...... as greenness estimated by lagged variation in monthly rainfall and temperature. This definition of drought performs well in identifying self-reported drought events since 2000 compared with measures of drought that do not take greenness into account, and the subsequent analysis indicates that predicted...... variation in greenness is positively associated with year-on-year changes in luminosity: If a unit of observation experiences a predicted variation in greenness that lies 1 standard deviation below the global mean, on average 1.5 - 2.5 light pixels out of 900 are extinguished that year. Finally, an attempt...

Aspects of the generation of finite-difference Green's function sequences for arbitrary 3-D cubic lattice points

NARCIS (Netherlands)

de Hon, B.P.; Arnold, J.M.

2015-01-01

The robust and speedy evaluation of lattice Green's functions LGFs) is crucial to the effectiveness of finite-difference Green's function diakoptics schemes. We have recently determined a generic recurrence scheme for the construction of scalar LGF sequences at arbitrary points on a 3-D cubic

Construction of U-gauge Green's functions of gauge theories with spontaneous symmetry breaking and Slavnov identities

International Nuclear Information System (INIS)

Flume, R.

1978-01-01

The unitary (U) gauge Green's functions of the U(1) and SU(2) Higgs-Kibble models are constructed applying a renormalized point transformation and a non-local gauge changing transformation to a manifestly renormalizable (R gauge) version of the respective theory. It is shown that the cancellation mechanism known as 'tree graph unitarity' rendering in tree graph approximation a smooth high energy behaviour of the U gauge Green's functions on mass shell can in a natural way be extended to all orders of perturbation theory. The conditions imposed by this 'generalized tree graph unitarity' on the renormalization programme are shown to be equivalent with the requirement of renormalized Slavnov identities for the R gauge Green's functions

The function of green belt Jatibarang as quality control for the environment of Semarang city

Science.gov (United States)

Murtini, Titien Woro; Harani, Arnis Rochma; Ernadia, Loretta

2017-06-01

The quality of the healthy environment in a neighborhood city is decreasing in number. According to the government regulation, Act No. 26 of 2007, a city should have 20% of green areas from the total area of the city. Now, Semarang only has 7.5% of green areas from the total city area. One of the efforts made by the Government of Semarang is the establishment of a greenbelt in Jatibarang area. It consists of several parts, namely, the reservoirs in the green belt area and also the plant zone in other sectors. The reservoir has a function as the controller of water resources sustainability where the crops serve as the balance for the combination. Thus, it is interesting to study how the interplay of these two functions in a green belt area. The primary data used in this study was obtained from the locus of research by direct observation, interview, and physical data collection. Based on the data collection, data was then processed and analyzed in accordance with the indicators that had been compiled based on theories of reservoirs, green belts, and the quality of the urban environment. Government regulations regarding with the greenbelt and tanks were also used as references in the discussion. The research found out that the presence of the reservoir and the plants in the green belt of Jatibarang can improve the function of the green belt optimally which is a real influence for the improvement of the environment quality, especially water. The Greenbelt was divided into four zones, namely the Arboretum, Argo - Forestry, Ecotourism, Buffer - Zone also made the region became a beautiful greenbelt that brought a positive influence to environmental quality.

Infra-red asymptotic behaviour of the one-fermion Green's function in a scalar model with isospin

International Nuclear Information System (INIS)

Popov, V.N.; Wu, T.T.

1979-01-01

In a theory where massive fermions interact with a massless scalar field of isospin 1, the behaviour of the one-fermion Green's function is found to differ from the free Green's function by a factor (1 - (2g 2 /π 2 )ln mmod(x-y))sup(-3/8), in the limit of large separation mod(x-y). (Auth.)

QCD Green's Functions and Phases of Strongly-Interacting Matter

Directory of Open Access Journals (Sweden)

Schaefer B.J.

2011-04-01

Full Text Available After presenting a brief summary of functional approaches to QCD at vanishing temperatures and densities the application of QCD Green's functions at non-vanishing temperature and vanishing density is discussed. It is pointed out in which way the infrared behavior of the gluon propagator reflects the (de-confinement transition. Numerical results for the quark propagator are given thereby verifying the relation between (de--confinement and dynamical chiral symmetry breaking (restoration. Last but not least some results of Dyson-Schwinger equations for the color-superconducting phase at large densities are shown.

Finite-difference Green's functions on a 3-D cubic lattice - Integer versus fixed-precision arithmetic recurrence schemes

NARCIS (Netherlands)

De Hon, B. P.; Arnold, J. M.

2016-01-01

Time-domain 3-D lattice Green's function (LGF) sequences can be evaluated using a single-lattice point recurrence scheme, and play an important role in finite-difference Green's function diakoptics. Asymptotically, at large distances, the LGFs in three dimensions can be described in terms of six

Green function iterative solution of ground state wave function for Yukawa potential

International Nuclear Information System (INIS)

Zhang Zhao

2003-01-01

The newly developed single trajectory quadrature method is applied to solve central potentials. First, based on the series expansion method an exact analytic solution of the ground state for Hulthen potential and an approximate solution for Yukawa potential are obtained respectively. Second, the newly developed iterative method based on Green function defined by quadratures along the single trajectory is applied to solve Yukawa potential using the Coulomb solution and Hulthen solution as the trial functions respectively. The results show that a more proper choice of the trial function will give a better convergence. To further improve the convergence the iterative method is combined with the variational method to solve the ground state wave function for Yukawa potential, using variational solutions of the Coulomb and Hulthen potentials as the trial functions. The results give much better convergence. Finally, the obtained critical screen coefficient is applied to discuss the dissociate temperature of J/ψ in high temperature QGP

The study of size and stability of n-butylcyanoacrylate nanocapsule suspensions encapsulating green grass fragrance

Science.gov (United States)

Zhu, G. Y.; Lin, C. T.; Chen, J. M.; Lei, D. M.; Zhu, G. X.

2018-01-01

Green grass fragrance has been widely used in many fields. However, fragrances are volatile compounds that do not last long. In order to prolong its odor, nanocapsules encapsulated green grass fragrance were prepared. The paper deals with the preparation of green grass fragrance nanocapsules by emulsion polymerization. N-butylcyanoacrylate (BCA) with excellent biocompatibility and biodegradability was used as encapsulant. The nanocapsule suspension systems were characterized and its stability was investigated. The physicochemical properties of polymeric nanocapsules (average diameter and polydispersity) were evaluated as a function of time to assess the system stability. The result showed that the system (containing 0.8% of green grass fragrance, with a polydispersity index (PDI) near 0.1 and an average diameter in the range of 20-30 nm) was an ideal state and relatively stable. Besides, the distinction of stability of three nanocapsule suspensions with different green grass fragrance content was also obvious from scanning electron microscopy (SEM).

Generalized relations among N-dimensional Coulomb Green's functions using fractional derivatives

International Nuclear Information System (INIS)

Blinder, S.M.; Pollock, E.L.

1989-01-01

Hostler [J. Math. Phys. 11, 2966 (1970)] has shown that Coulomb Green's functions of different dimensionality N are related by G (N+2) =OG (N) , where O is a first-order derivative operator in the variables x and y. Thus all the even-dimensional functions are connected, as are analogously the odd-dimensional functions. It is shown that the operations of functional differentiation and integration can further connect the even- to the odd-dimensional functions, so that Hostler's relation can be extended to give G (N+1) =O 1/2 G (N)

The statistical error of Green's function Monte Carlo

International Nuclear Information System (INIS)

Ceperley, D.M.

1986-01-01

The statistical error in the ground state energy as calculated by Green's Function Monte Carlo (GFMC) is analyzed and a simple approximate formula is derived which relates the error to the number of steps of the random walk, the variational energy of the trial function, and the time step of the random walk. Using this formula it is argued that as the thermodynamic limit is approached with N identical molecules, the computer time needed to reach a given error per molecule increases as N/sup n/ where 0.5 < b < 1.5 and as the nuclear charge Z of a system is increased the computer time necessary to reach a given error grows as Z/sup 5.5/. Thus GFMC simulations will be most useful for calculating the properties of low Z elements. The implications for choosing the optimal trial function from a series of trial functions is also discussed

Estimates for the mixed derivatives of the Green functions on homogeneous manifolds of negative curvature

Directory of Open Access Journals (Sweden)

Roman Urban

2004-12-01

Full Text Available We consider the Green functions for second-order left-invariant differential operators on homogeneous manifolds of negative curvature, being a semi-direct product of a nilpotent Lie group $N$ and $A=mathbb{R}^+$. We obtain estimates for mixed derivatives of the Green functions both in the coercive and non-coercive case. The current paper completes the previous results obtained by the author in a series of papers [14,15,16,19].

GREEN GALAXIES IN THE COSMOS FIELD

International Nuclear Information System (INIS)

Pan, Zhizheng; Kong, Xu; Fan, Lulu

2013-01-01

We present research on the morphologies, spectra, and environments of ≈2350 'green valley' galaxies at 0.2 + color is used to define 'green valley'; it removes dusty star-forming galaxies from galaxies that are truly transitioning between the blue cloud and the red sequence. Morphological parameters of green galaxies are intermediate between those of blue and red galaxy populations, both on the Gini-asymmetry and the Gini-M 20 planes. Approximately 60%-70% of green disk galaxies have intermediate or big bulges, and only 5%-10% are pure disk systems, based on morphological classification using the Zurich Estimator of Structural Types. The obtained average spectra of green galaxies are intermediate between blue and red ones in terms of [O II], Hα, and Hβ emission lines. Stellar population synthesis on the average spectra shows that green galaxies are on average older than blue galaxies but younger than red galaxies. Green galaxies and blue galaxies have similar projected galaxy density (Σ 10 ) distributions at z > 0.7. At z * 10.0 M ☉ green galaxies located in a dense environment are found to be significantly larger than those of blue galaxies. The morphological and spectral properties of green galaxies are consistent with the transitioning population between the blue cloud and the red sequence. The possible mechanisms for quenching star formation activities in green galaxies are discussed. The importance of active galactic nucleus feedback cannot be well constrained in our study. Finally, our findings suggest that environmental conditions, most likely starvation and harassment, significantly affect the transformation of M * 10.0 M ☉ blue galaxies into red galaxies, especially at z < 0.5

Finite-Source Inversion for the 2004 Parkfield Earthquake using 3D Velocity Model Green's Functions

Science.gov (United States)

Kim, A.; Dreger, D.; Larsen, S.

2008-12-01

We determine finite fault models of the 2004 Parkfield earthquake using 3D Green's functions. Because of the dense station coverage and detailed 3D velocity structure model in this region, this earthquake provides an excellent opportunity to examine how the 3D velocity structure affects the finite fault inverse solutions. Various studies (e.g. Michaels and Eberhart-Phillips, 1991; Thurber et al., 2006) indicate that there is a pronounced velocity contrast across the San Andreas Fault along the Parkfield segment. Also the fault zone at Parkfield is wide as evidenced by mapped surface faults and where surface slip and creep occurred in the 1966 and the 2004 Parkfield earthquakes. For high resolution images of the rupture process"Ait is necessary to include the accurate 3D velocity structure for the finite source inversion. Liu and Aurchuleta (2004) performed finite fault inversions using both 1D and 3D Green's functions for 1989 Loma Prieta earthquake using the same source paramerization and data but different Green's functions and found that the models were quite different. This indicates that the choice of the velocity model significantly affects the waveform modeling at near-fault stations. In this study, we used the P-wave velocity model developed by Thurber et al (2006) to construct the 3D Green's functions. P-wave speeds are converted to S-wave speeds and density using by the empirical relationships of Brocher (2005). Using a finite difference method, E3D (Larsen and Schultz, 1995), we computed the 3D Green's functions numerically by inserting body forces at each station. Using reciprocity, these Green's functions are recombined to represent the ground motion at each station due to the slip on the fault plane. First we modeled the waveforms of small earthquakes to validate the 3D velocity model and the reciprocity of the Green"fs function. In the numerical tests we found that the 3D velocity model predicted the individual phases well at frequencies lower than 0

Numerical simulation of electromagnetic waves in Schwarzschild space-time by finite difference time domain method and Green function method

Science.gov (United States)

Jia, Shouqing; La, Dongsheng; Ma, Xuelian

2018-04-01

The finite difference time domain (FDTD) algorithm and Green function algorithm are implemented into the numerical simulation of electromagnetic waves in Schwarzschild space-time. FDTD method in curved space-time is developed by filling the flat space-time with an equivalent medium. Green function in curved space-time is obtained by solving transport equations. Simulation results validate both the FDTD code and Green function code. The methods developed in this paper offer a tool to solve electromagnetic scattering problems.

Wave resistance calculation method combining Green functions based on Rankine and Kelvin source

Directory of Open Access Journals (Sweden)

LI Jingyu

2017-12-01

Full Text Available [Ojectives] At present, the Boundary Element Method(BEM of wave-making resistance mostly uses a model in which the velocity distribution near the hull is solved first, and the pressure integral is then calculated using the Bernoulli equation. However,the process of this model of wave-making resistance is complex and has low accuracy.[Methods] To address this problem, the present paper deduces a compound method for the quick calculation of ship wave resistance using the Rankine source Green function to solve the hull surface's source density, and combining the Lagally theorem concerning source point force calculation based on the Kelvin source Green function so as to solve the wave resistance. A case for the Wigley model is given.[Results] The results show that in contrast to the thin ship method of the linear wave resistance theorem, this method has higher precision, and in contrast to the method which completely uses the Kelvin source Green function, this method has better computational efficiency.[Conclusions] In general, the algorithm in this paper provides a compromise between precision and efficiency in wave-making resistance calculation.

Order- N Green's Function Technique for Local Environment Effects in Alloys

DEFF Research Database (Denmark)

Abrikosov, I. A.; Niklasson, A. M. N.; Simak, S. I.

1996-01-01

We have developed a new approach to the calculations of ground state properties of large crystalline systems with arbitrary atomic configurations based on a Green's function technique in conjunction with a self-consistent effective medium for the underlying randomly occupied lattice. The locally...

Optimum Design of Multi-Function Robot Arm Gripper for Varying Shape Green Product

Directory of Open Access Journals (Sweden)

Razali Zol Bahri

2016-01-01

Full Text Available The project focuses on thorough experimentally studies of the optimum design of Multi-function Robot Arm Gripper for varying shape green product. The purpose of this project is to design a few of robot arm gripper for multi-functionally grip a green product with varying shape. The main character of the gripper is that it can automated adjust its finger to suit with the shape of the product. An optimum design of multi-function robot arm gripper is verified through experimental study. The expected result is a series of analytical results on the proposal of gripper design and material that will be selected for the gripper. The analysis of the gripper design proposal by using ANSYS and CATIA software is described in detail in this paper.

Efficient and high-power green beam generation by frequency ...

Indian Academy of Sciences (India)

Rz; 42.60.Gd. 1. Introduction. High-average-power green lasers are required for various applications in industry, ... mode size, however, vary dynamically with the pump power due to thermal lensing in the Nd:YAG rod. ... fundamental mode size at the Nd:YAG rod as well as at the KTP crystal is plotted as a function of the ...

The Hadamard construction of Green's functions on a curved space-time: physics and explicit rigorous results

International Nuclear Information System (INIS)

John, R.W.

1987-01-01

First, in connection with their construction due to Hadamard, the mathematical and physical meaning of covariant Green's functions in relativistic gravitational fields - according to Einstein: on curved space-time - is discussed. Then, in the case of a general static spherically symmetric space-time the construction equations for a scalar Green's function are cast into symmetry-adapted form providing a convenient starting point for an explicit calculation of the Hadamard building elements. In applying the obtained basic scheme to a special one-parameter family of model metrics one succeeds in advancing to the explicit exact calculation of tail-term coefficients of a massless Green's function which are simultaneously coefficients in the Schwinger-De Witt expansion of the Feynman propagator for the corresponding massive Klein-Gordon equation on curved space-time. (author)

GREEN GALAXIES IN THE COSMOS FIELD

Energy Technology Data Exchange (ETDEWEB)

Pan, Zhizheng; Kong, Xu; Fan, Lulu, E-mail: panzz@mail.ustc.edu.cn, E-mail: xkong@ustc.edu.cn [Center of Astrophysics, University of Science and Technology of China, Hefei 230026 (China)

2013-10-10

We present research on the morphologies, spectra, and environments of ≈2350 'green valley' galaxies at 0.2 < z < 1.0 in the COSMOS field. The bimodality of dust-corrected NUV–r {sup +} color is used to define 'green valley'; it removes dusty star-forming galaxies from galaxies that are truly transitioning between the blue cloud and the red sequence. Morphological parameters of green galaxies are intermediate between those of blue and red galaxy populations, both on the Gini-asymmetry and the Gini-M{sub 20} planes. Approximately 60%-70% of green disk galaxies have intermediate or big bulges, and only 5%-10% are pure disk systems, based on morphological classification using the Zurich Estimator of Structural Types. The obtained average spectra of green galaxies are intermediate between blue and red ones in terms of [O II], Hα, and Hβ emission lines. Stellar population synthesis on the average spectra shows that green galaxies are on average older than blue galaxies but younger than red galaxies. Green galaxies and blue galaxies have similar projected galaxy density (Σ{sub 10}) distributions at z > 0.7. At z < 0.7, the fractions of M{sub *} < 10{sup 10.0} M{sub ☉} green galaxies located in a dense environment are found to be significantly larger than those of blue galaxies. The morphological and spectral properties of green galaxies are consistent with the transitioning population between the blue cloud and the red sequence. The possible mechanisms for quenching star formation activities in green galaxies are discussed. The importance of active galactic nucleus feedback cannot be well constrained in our study. Finally, our findings suggest that environmental conditions, most likely starvation and harassment, significantly affect the transformation of M{sub *} < 10{sup 10.0} M{sub ☉} blue galaxies into red galaxies, especially at z < 0.5.

Green's function method for perturbed Korteweg-de Vries equation

International Nuclear Information System (INIS)

Cai Hao; Huang Nianning

2003-01-01

The x-derivatives of squared Jost solution are the eigenfunctions with the zero eigenvalue of the linearized equation derived from the perturbed Korteweg-de Vries equation. A method similar to Green's function formalism is introduced to show the completeness of the squared Jost solutions in multi-soliton cases. It is not related to Lax equations directly, and thus it is beneficial to deal with the nonlinear equations with complicated Lax pair

Green's function Monte Carlo calculations of /sup 4/He

Energy Technology Data Exchange (ETDEWEB)

Carlson, J.A.

1988-01-01

Green's Function Monte Carlo methods have been developed to study the ground state properties of light nuclei. These methods are shown to reproduce results of Faddeev calculations for A = 3, and are then used to calculate ground state energies, one- and two-body distribution functions, and the D-state probability for the alpha particle. Results are compared to variational Monte Carlo calculations for several nuclear interaction models. 31 refs.

An integral transform of Green's function, off-shell Jost solution and T ...

Indian Academy of Sciences (India)

integral transform of the Green's function for motion in Coulomb–Yamaguchi potential is derived via the r-space ... use in the calculation of the corresponding off-shell quantities without the explicit use of two-potential theorem and ..... (x), spherical Bessel function and gli(βli,r)s, the form factors of the sep- arable potential the ...

Development of multi-functional streetscape green infrastructure using a performance index approach

Czech Academy of Sciences Publication Activity Database

Tiwary, A.; Williams, L. D.; Heidrich, O.; Namdeo, A.; Bandaru, V.; Calfapietra, Carlo

2016-01-01

Roč. 208, jan (2016), s. 209-220 ISSN 0269-7491 Institutional support: RVO:67179843 Keywords : Green infrastructure * Multi-functional * Pollution * Performance index * Streetscape Subject RIV: EH - Ecology, Behaviour Impact factor: 5.099, year: 2016

An extended diffraction tomography method for quantifying structural damage using numerical Green's functions.

Science.gov (United States)

Chan, Eugene; Rose, L R Francis; Wang, Chun H

2015-05-01

Existing damage imaging algorithms for detecting and quantifying structural defects, particularly those based on diffraction tomography, assume far-field conditions for the scattered field data. This paper presents a major extension of diffraction tomography that can overcome this limitation and utilises a near-field multi-static data matrix as the input data. This new algorithm, which employs numerical solutions of the dynamic Green's functions, makes it possible to quantitatively image laminar damage even in complex structures for which the dynamic Green's functions are not available analytically. To validate this new method, the numerical Green's functions and the multi-static data matrix for laminar damage in flat and stiffened isotropic plates are first determined using finite element models. Next, these results are time-gated to remove boundary reflections, followed by discrete Fourier transform to obtain the amplitude and phase information for both the baseline (damage-free) and the scattered wave fields. Using these computationally generated results and experimental verification, it is shown that the new imaging algorithm is capable of accurately determining the damage geometry, size and severity for a variety of damage sizes and shapes, including multi-site damage. Some aspects of minimal sensors requirement pertinent to image quality and practical implementation are also briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

A Radiation Chemistry Code Based on the Greens Functions of the Diffusion Equation

Science.gov (United States)

Plante, Ianik; Wu, Honglu

2014-01-01

Ionizing radiation produces several radiolytic species such as.OH, e-aq, and H. when interacting with biological matter. Following their creation, radiolytic species diffuse and chemically react with biological molecules such as DNA. Despite years of research, many questions on the DNA damage by ionizing radiation remains, notably on the indirect effect, i.e. the damage resulting from the reactions of the radiolytic species with DNA. To simulate DNA damage by ionizing radiation, we are developing a step-by-step radiation chemistry code that is based on the Green's functions of the diffusion equation (GFDE), which is able to follow the trajectories of all particles and their reactions with time. In the recent years, simulations based on the GFDE have been used extensively in biochemistry, notably to simulate biochemical networks in time and space and are often used as the "gold standard" to validate diffusion-reaction theories. The exact GFDE for partially diffusion-controlled reactions is difficult to use because of its complex form. Therefore, the radial Green's function, which is much simpler, is often used. Hence, much effort has been devoted to the sampling of the radial Green's functions, for which we have developed a sampling algorithm This algorithm only yields the inter-particle distance vector length after a time step; the sampling of the deviation angle of the inter-particle vector is not taken into consideration. In this work, we show that the radial distribution is predicted by the exact radial Green's function. We also use a technique developed by Clifford et al. to generate the inter-particle vector deviation angles, knowing the inter-particle vector length before and after a time step. The results are compared with those predicted by the exact GFDE and by the analytical angular functions for free diffusion. This first step in the creation of the radiation chemistry code should help the understanding of the contribution of the indirect effect in the

The Impact of Working in a Green Certified Building on Cognitive Function and Health.

Science.gov (United States)

MacNaughton, Piers; Satish, Usha; Laurent, Jose Guillermo Cedeno; Flanigan, Skye; Vallarino, Jose; Coull, Brent; Spengler, John D; Allen, Joseph G

2017-03-01

Thirty years of public health research have demonstrated that improved indoor environmental quality is associated with better health outcomes. Recent research has demonstrated an impact of the indoor environment on cognitive function. We recruited 109 participants from 10 high-performing buildings (i.e. buildings surpassing the ASHRAE Standard 62.1-2010 ventilation requirement and with low total volatile organic compound concentrations) in five U.S. cities. In each city, buildings were matched by week of assessment, tenant, type of worker and work functions. A key distinction between the matched buildings was whether they had achieved green certification. Workers were administered a cognitive function test of higher order decision-making performance twice during the same week while indoor environmental quality parameters were monitored. Workers in green certified buildings scored 26.4% (95% CI: [12.8%, 39.7%]) higher on cognitive function tests, controlling for annual earnings, job category and level of schooling, and had 30% fewer sick building symptoms than those in non-certified buildings. These outcomes may be partially explained by IEQ factors, including thermal conditions and lighting, but the findings suggest that the benefits of green certification standards go beyond measureable IEQ factors. We describe a holistic "buildingomics" approach for examining the complexity of factors in a building that influence human health.

Analytical determination of Kondo and Fano resonances of electron Green's function in a single-level quantum dot

International Nuclear Information System (INIS)

Nguyen Bich Ha; Nguyen Van Hop

2009-01-01

The Kondo and Fano resonances in the two-point Green's function of the single-level quantum dot were found and investigated in many previous works by means of different numerical calculation methods. In this work we present the derivation of the analytical expressions of resonance terms in the expression of the two-point Green's function. For that purpose the system of Dyson equations for the two-point nonequilibrium Green's functions in the complex-time Keldysh formalism was established in the second order with respect to the tunneling coupling constants and the mean field approximation. This system of Dyson equations was solved exactly and the analytical expressions of the resonance terms are derived. The conditions for the existence of Kondo or Fano resonances are found.

The bosonic thermal Green function, its dual, and the fermion correlators of the massive Thirring model at finite temperature

International Nuclear Information System (INIS)

Mondaini, Leonardo; Marino, E.C.

2011-01-01

Full text: Despite the fact that quantum field theories are usually formulated in coordinate space, calculations, in both T = 0 and T ≠ 0 cases, are almost always performed in momentum space. However, when we are faced with the exact calculation of correlation functions we are naturally led to the problem of finding closed-form expressions for Green functions in coordinate space. In the present work, we derive an exact closed-form representation for the Euclidian thermal Green function of the two-dimensional (2D) free massless scalar field in coordinate space. This can be interpreted as the real part of a complex analytic function of a variable that conformally maps the infinite strip -∞ < x < ∞ (0 < τ < β of the z = x + iτ (τ: imaginary time) plane into the upper-half-plane. Use of the Cauchy-Riemann conditions, then allows us to identify the dual thermal Green function as the imaginary part of that function. Using both the thermal Green function and its dual, we obtain an explicit series expression for the fermionic correlation functions of the massive Thirring model (MTM) at a finite temperature. (author)

A hybrid method for the parallel computation of Green's functions

DEFF Research Database (Denmark)

Petersen, Dan Erik; Li, Song; Stokbro, Kurt

2009-01-01

of the large number of times this calculation needs to be performed, this is computationally very expensive even on supercomputers. The classical approach is based on recurrence formulas which cannot be efficiently parallelized. This practically prevents the solution of large problems with hundreds...... of thousands of atoms. We propose new recurrences for a general class of sparse matrices to calculate Green's and lesser Green's function matrices which extend formulas derived by Takahashi and others. We show that these recurrences may lead to a dramatically reduced computational cost because they only...... require computing a small number of entries of the inverse matrix. Then. we propose a parallelization strategy for block tridiagonal matrices which involves a combination of Schur complement calculations and cyclic reduction. It achieves good scalability even on problems of modest size....

Discontinuities of Green functions in field theory at finite temperature and density

International Nuclear Information System (INIS)

Kobes, R.L.; Semenoff, G.W.

1985-01-01

We derive systematic rules for calculating the imaginary parts of Minkowski space Green functions in quantum field theory at finite temperature and density. Self-energy corrections are used as an example of the application of these rules. (orig.)

Solving two-dimensions heat conduction problem for fuel elements in reactor by nodal green's function method

International Nuclear Information System (INIS)

Tang Jian; Peng Muzhang; Cao Dongxing

1989-01-01

A new numerical method-nodal green's function method is used for solving heat conduction function. A heat conduction problem in cylindrical geometry with axial conduction is solved in this paper. The Kirchhoff transformation is used to deal with the problem with temperature dependent conductivity. Therefor, the calculation for the function is simplified. On the basis of the formulas developed, the code named NGMEFC is programmed. A sample problem which has been calculated by the code COBRA-IV is chosen as checking. A good agreement between both codes is achieved. The calculation shows that the calculation efficiency of the nodel green's function method is much higher than that of finite difference method

METHOD OF GREEN FUNCTIONS IN MATHEMATICAL MODELLING FOR TWO-POINT BOUNDARY-VALUE PROBLEMS

Directory of Open Access Journals (Sweden)

E. V. Dikareva

2015-01-01

Full Text Available Summary. In many applied problems of control, optimization, system theory, theoretical and construction mechanics, for problems with strings and nods structures, oscillation theory, theory of elasticity and plasticity, mechanical problems connected with fracture dynamics and shock waves, the main instrument for study these problems is a theory of high order ordinary differential equations. This methodology is also applied for studying mathematical models in graph theory with different partitioning based on differential equations. Such equations are used for theoretical foundation of mathematical models but also for constructing numerical methods and computer algorithms. These models are studied with use of Green function method. In the paper first necessary theoretical information is included on Green function method for multi point boundary-value problems. The main equation is discussed, notions of multi-point boundary conditions, boundary functionals, degenerate and non-degenerate problems, fundamental matrix of solutions are introduced. In the main part the problem to study is formulated in terms of shocks and deformations in boundary conditions. After that the main results are formulated. In theorem 1 conditions for existence and uniqueness of solutions are proved. In theorem 2 conditions are proved for strict positivity and equal measureness for a pair of solutions. In theorem 3 existence and estimates are proved for the least eigenvalue, spectral properties and positivity of eigenfunctions. In theorem 4 the weighted positivity is proved for the Green function. Some possible applications are considered for a signal theory and transmutation operators.

Green's functions of one-dimensional quasicrystal bi-material with piezoelectric effect

Energy Technology Data Exchange (ETDEWEB)

Zhang, Liangliang [College of Engineering, China Agricultural University, Beijing 100083 (China); Sinomatech Wind Power Blade Co., Ltd, Beijing 100092 (China); Wu, Di [College of Engineering, China Agricultural University, Beijing 100083 (China); Xu, Wenshuai [College of Science, China Agricultural University, Beijing 100083 (China); Yang, Lianzhi [Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083 (China); Ricoeur, Andreas; Wang, Zhibin [Institute of Mechanics, University of Kassel, 34125 Kassel (Germany); Gao, Yang, E-mail: gaoyangg@gmail.com [College of Science, China Agricultural University, Beijing 100083 (China)

2016-09-16

Based on the Stroh formalism of one-dimensional quasicrystals with piezoelectric effect, the problems of an infinite plane composed of two different quasicrystal half-planes are taken into account. The solutions of the internal and interfacial Green's functions of quasicrystal bi-material are obtained. Moreover, numerical examples are analyzed for a quasicrystal bi-material subjected to line forces or line dislocations, showing the contour maps of the coupled fields. The impacts of changing material constants on the coupled field components are investigated. - Highlights: • Green's functions of 1D piezoelectric quasicrystal bi-material are studied. • The coupled fields subjected to line forces or line dislocations are obtained. • Mechanical behavior under the effect of different material constants is researched.

Adaptation of light-harvesting functions of unicellular green algae to different light qualities.

Science.gov (United States)

Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

2018-05-28

Oxygenic photosynthetic organisms perform photosynthesis efficiently by distributing captured light energy to photosystems (PSs) at an appropriate balance. Maintaining photosynthetic efficiency under changing light conditions requires modification of light-harvesting and energy-transfer processes. In the current study, we examined how green algae regulate their light-harvesting functions in response to different light qualities. We measured low-temperature time-resolved fluorescence spectra of unicellular green algae Chlamydomonas reinhardtii and Chlorella variabilis cells grown under different light qualities. By observing the delayed fluorescence spectra, we demonstrated that both types of green algae primarily modified the associations between light-harvesting chlorophyll protein complexes (LHCs) and PSs (PSII and PSI). Under blue light, Chlamydomonas transferred more energy from LHC to chlorophyll (Chl) located far from the PSII reaction center, while energy was transferred from LHC to PSI via different energy-transfer pathways in Chlorella. Under green light, both green algae exhibited enhanced energy transfer from LHCs to both PSs. Red light induced fluorescence quenching within PSs in Chlamydomonas and LHCs in Chlorella. In Chlorella, energy transfer from PSII to PSI appears to play an important role in balancing excitation between PSII and PSI.

The closed time-path Green function formalism in many-body theory

International Nuclear Information System (INIS)

Guang-zhao Zhou; Zhao-bin Su; Bai-lin Hao; Lu Yu.

1983-09-01

The closed time-path Green function formalism, developed by our group during recent years, is briefly reviewed. The generating functional technique, the coupled equations for the order parameter and the elementary excitations as well as the systematic loop expansion are outlined. The applications to critical dynamics, quenched random systems, nonlinear response theory, superconductivity, laser system and quasi-one-dimensional conductors are described. The theoretical approach developed can be applied to both equilibrium and non-equilibrium many-body systems. (author)

Magnetic field effects on the quantum wire energy spectrum and Green's function

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J.

2010-01-01

We analyze the energy spectrum and propagation of electrons in a quantum wire on a 2D host medium in a normal magnetic field, representing the wire by a 1D Dirac delta function potential which would support just a single subband state in the absence of the magnetic field. The associated Schroedinger Green's function for the quantum wire is derived in closed form in terms of known functions and the Landau quantized subband energy spectrum is examined.

About sign-constancy of Green's functions for impulsive second order delay equations

Directory of Open Access Journals (Sweden)

Alexander Domoshnitsky

2014-01-01

Full Text Available We consider the following second order differential equation with delay \\[\\begin{cases} (Lx(t\\equiv{x''(t+\\sum_{j=1}^p {b_{j}(tx(t-\\theta_{j}(t}}=f(t, \\quad t\\in[0,\\omega],\\\\ x(t_j=\\gamma_{j}x(t_j-0, x'(t_j=\\delta_{j}x'(t_j-0, \\quad j=1,2,\\ldots,r. \\end{cases}\\] In this paper we find necessary and sufficient conditions of positivity of Green's functions for this impulsive equation coupled with one or two-point boundary conditions in the form of theorems about differential inequalities. By choosing the test function in these theorems, we obtain simple sufficient conditions. For example, the inequality \\(\\sum_{i=1}^p{b_i(t\\left(\\frac{1}{4}+r\\right}\\lt \\frac{2}{\\omega^2}\\ is a basic one, implying negativity of Green's function of two-point problem for this impulsive equation in the case \\(0\\lt \\gamma_i\\leq{1}\\, \\(0\\lt \\delta_i\\leq{1}\\ for \\(i=1,\\ldots ,p\\.

Green's function for a neutral particle of spin 1/2 in a magnetic field; Funcoes de Green para uma particula neutra de spin 1/2 num campo magnetico

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Rafael de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Vaidya, Arvind Narayan [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

2001-12-01

Using the spectral theorema in context of Green's function in momentum space of neutrons in the magnetic field of a linear conductor with current the bound state energy spectrum and eigenfunctions are deduced. It's also pointed out that this problem present a new scenary of Green's function in non-relativistic quantum mechanics. (author)

Green function theory of random ferromagnets with large exchange anisotropy

International Nuclear Information System (INIS)

Patterson, J.D.

1977-01-01

Spin 1/2 systems which are coupled with an Ising-like Hamiltonian with fluctuating exchange are discussed by the use of thermodynamic Green functions in four different approximations. The first is equivalent to a local mean field approximation and the second is an approximation to the first in which the local mean field is assumed to be proportional to the overall magnetization and to the sum of the neighboring exchange 'bonds'. The third is also a special case of the first, but the local mean field is approximated in such a way as to be appropriate for the discussion of spin glasses. The fourth is a coherent potential-like approximation (CPA). The second approximation can be shown to imply no reduction of the Curie temperature (T sub(c)) due to exchange fluctuations, while the CPA does result in a lowering of T sub(c) (assuming small fluctuations about an average positive exchange in both cases). However, the CPA that was used is also an approximation to the second method. Hence, even though the CPA does result in a lowering of T sub(c) (which is generally conceded to be correct for the original model), this fact cannot be used as an argument for the validity of the CPA. This calculation thus emphasizes the necessity of critically examining any CPA-like calculation before accepting its predictions as valid [pt

Off-Shell Green Functions: One-Loop with Growing Legs

International Nuclear Information System (INIS)

Bashir, A.; Concha-Sanchez, Y.; Delbourgo, R.; Tejeda-Yeomans, M. E.

2008-01-01

One loop calculations in gauge theories in arbitrary gauge and dimensions become exceedingly hard with growing number of external off-shell legs. Let alone higher point functions, such a calculation for even the three point one-loop vertices for quantum electrodynamics (QED) and quantum chromodynamics (QCD) has been made available only recently. In this article, we discuss how Ward-Fradkin-Green-Takahashi identities (WFGTI) may provide a helpful tool in these computations. After providing a glimpse of our suggestion for the case of the 3-point vertex, we present our preliminary findings towards our similar efforts for the 4-point function. We restrict ourselves to the example of scalar quantum electrodynamics (SQED)

Computation of Green function of the Schroedinger-like partial differential equations by the numerical functional integration

International Nuclear Information System (INIS)

Lobanov, Yu.Yu.; Shahbagian, R.R.; Zhidkov, E.P.

1991-01-01

A new method for numerical solution of the boundary problem for Schroedinger-like partial differential equations in R n is elaborated. The method is based on representation of multidimensional Green function in the form of multiple functional integral and on the use of approximation formulas which are constructed for such integrals. The convergence of approximations to the exact value is proved, the remainder of the formulas is estimated. Method reduces the initial differential problem to quadratures. 16 refs.; 7 tabs

A line source in Minkowski for the de Sitter spacetime scalar Green's function: Massless minimally coupled case

International Nuclear Information System (INIS)

Chu, Yi-Zen

2014-01-01

Motivated by the desire to understand the causal structure of physical signals produced in curved spacetimes – particularly around black holes – we show how, for certain classes of geometries, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to (d ≥ 2)-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient (d + 1)-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero mode solution to an ordinary differential equation, the “wave equation” perpendicular to the hyperboloid – followed by a one-dimensional integral – needs to be evaluated. A topological obstruction to the general construction is also discussed by utilizing it to derive a generalized Green's function of the Laplacian on the (d ≥ 2)-dimensional sphere

Green Functions For Multiple Scattering As Mathematical Tools For Dense Cloud Remote Sensing: Theory, With Passive And Active Applications

International Nuclear Information System (INIS)

Davis, A.B.; Marshak, A.; Cahalan, R.F.

2001-01-01

We survey radiative Green function theory (1) in linear transport theory where numerical procedures are required to obtain specific results and (2) in the photon diffusion limit (large optical depths) where it is analytically tractable, at least for homogeneous plane-parallel media. We then describe two recent applications of Green function theory to passive cloud remote sensing in the presence of strong three-dimensional transport effects. Finally, we describe recent instrumental breakthroughs in 'off-beam' cloud lidar which is based on direct measurements of radiative Green functions with special attention to the data collected during the Shuttle-based Lidar In-space Technology Experiment (LITE) mission.

Green Functions for the Radial Electric Component of the Monopole Wake Field in a Round Resistive Chamber

International Nuclear Information System (INIS)

Zimmermann, Frank

1998-01-01

We compare different approximations to the point-charge Green function for the radial electric monopole field excited by an ultrarelativistic particle propagating through a resistive pipe, and study the applicability of these approximations for calculating the field of a bunch with finite length. It has been speculated that the exact form of the electric field could be important for simulations of the electron-cloud instability. In this paper, we show, however, that the usual approximation of the Green function by a delta function is adequate, except for extremely short bunch lengths

A theoretical approach to dynamical diffraction of X-rays in the Bragg case with the Green's function method

International Nuclear Information System (INIS)

Ishida, Hidenobu

2015-01-01

The dynamical diffraction theory of X-rays for a distorted crystal with the Green's function method is applied to the Bragg case. The transmitted and diffracted crystal waves are represented as the solutions of the integral equations using the Green's function. For a perfect crystal, the most exact form of the solution of the equations is given by the Green's function and its derivatives, and the waves are analytically expressed by using them. The results can be applied in a general case where the amplitude modulation of the incident wave is not negligibly small compared with the wave vector. If the amplitude modulation is small, those results are reduced essentially to the same as those given by Takagi's theory. (author)

Genus one super-Green function revisited and superstring amplitudes with non-maximal supersymmetry

International Nuclear Information System (INIS)

Itoyama, H.; Yano, Kohei

2016-01-01

We reexamine genus one super-Green functions with general boundary conditions twisted by (α,β) for (σ,τ) directions in the eigenmode expansion and derive expressions as infinite series of hypergeometric functions. Using these, we compute one-loop superstring amplitudes with non-maximal supersymmetry, taking the example of massless vector emissions of open string type I Z 2 orbifold

The Role of Stakeholders Related to the Management of Ecological Function of Urban Green Open Space. Case Study: City of Depok, Indonesia

Science.gov (United States)

Mangopa Malik, Andy Anton

2017-12-01

Urban green open space is one of the assets that provide substantial benefits to the urban community. One important function of urban green open space is a function of ecology. This study will provide initial explanation on the various studies related to the ecological function of urban green open space. The study of urban space management approach related to ecological function will explain the extent of the role of stakeholders in the urban areas that will further strengthen the importance of the existence of green open space, especially in city of Depok. With so many problems related to the supply and use of green open space in the city of Depok. This approach was originally applied by the private sector and many applications made a great contribution, so it began to be used by the government in managing public assets there. This study will use descriptive method, at the beginning of the study will explain the existence of the reality of urban green open space as part of the urban space by viewing it from theoretical overview of space, function and role of the various problems that occur in it. The results of this study indicate there are six problems in the management of green open spaces in city of Depok. Using the stages in asset management will provide space for participation of existing stakeholders in the management of green open spaces in city of Depok.

Source analysis using regional empirical Green's functions: The 2008 Wells, Nevada, earthquake

Science.gov (United States)

Mendoza, C.; Hartzell, S.

2009-01-01

We invert three-component, regional broadband waveforms recorded for the 21 February 2008 Wells, Nevada, earthquake using a finite-fault methodology that prescribes subfault responses using eight MW∼4 aftershocks as empirical Green's functions (EGFs) distributed within a 20-km by 21.6-km fault area. The inversion identifies a seismic moment of 6.2 x 1024 dyne-cm (5.8 MW) with slip concentrated in a compact 6.5-km by 4-km region updip from the hypocenter. The peak slip within this localized area is 88 cm and the stress drop is 72 bars, which is higher than expected for Basin and Range normal faults in the western United States. The EGF approach yields excellent fits to the complex regional waveforms, accounting for strong variations in wave propagation and site effects. This suggests that the procedure is useful for studying moderate-size earthquakes with limited teleseismic or strong-motion data and for examining uncertainties in slip models obtained using theoretical Green's functions.

Phonon conductivity and relaxation rate in solids with disturbances by the Green function method

International Nuclear Information System (INIS)

Singh, M.

1980-09-01

In this present article we have established an expression for the temperature dependence of the lattice thermal conductivity of solids with harmonic disturbances. The relaxation rate for scattering of phonons with point defect is also derived. We will apply the Kubo-correlation function formalism for the thermal conductivity, and the double time temperature dependent Green function technique for the evaluation of correlation functions

The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect

Directory of Open Access Journals (Sweden)

Kouki Fujioka

2016-04-01

Full Text Available For serving green tea, there are two prominent methods: steeping the leaf or the powdered leaf (matcha style in hot water. The purpose of the present study was to reveal chemical and functional differences before and after the powdering process of green tea leaf, since powdered green tea may contribute to expanding the functionality because of the different ingesting style. In this study, we revealed that the powdering process with a ceramic mill and stirring in hot water increased the average extracted concentration of epigallocatechin gallate (EGCG by more than three times compared with that in leaf tea using high-performance liquid chromatography (HPLC and liquid chromatography–tandem mass Spectrometry (LC-MS/MS analyses. Moreover, powdered green tea has a higher inhibition effect of reactive oxygen species (ROS production in vitro compared with the same amount of leaf tea. Our data suggest that powdered green tea might have a different function from leaf tea due to the higher catechin contents and particles.

Time-dependent inversions of slow slip at the Hikurangi subduction zone, New Zealand, using numerical Green's functions

Science.gov (United States)

Williams, C. A.; Wallace, L. M.; Bartlow, N. M.

2017-12-01

Slow slip events (SSEs) have been observed throughout the world, and the existence of these events has fundamentally altered our understanding of the possible ranges of slip behavior at subduction plate boundaries. In New Zealand, SSEs occur along the Hikurangi Margin, with shallower events in the north and deeper events to the south. In a recent study, Williams and Wallace (2015) found that static SSE inversions that consider elastic property variations provided significantly different results than those based on an elastic half-space. For deeper events, the heterogeneous models predicted smaller amounts of slip, while for shallower events the heterogeneous model predicted larger amounts of slip. In this study, we extend our initial work to examine the temporal variations in slip. We generate Green's functions using the PyLith finite element code (Aagaard et al., 2013) to allow consideration of elastic property variations provided by the New Zealand-wide seismic velocity model (Eberhart-Phillips et al., 2010). These Green's functions are then integrated to provide Green's functions compatible with the Network Inversion Filter (NIF, Segall and Matthews,1997; McGuire and Segall, 2003; Miyazaki et al.,2006). We examine 12 SSEs occurring along the Hikurangi Margin during 2010 and 2011, and compare the results using heterogeneous Green's functions with those of Bartlow et al. (2014), who examined the same set of SSEs with the NIF using a uniform elastic half-space model. The use of heterogeneous Green's functions should provide a more accurate picture of the slip distribution and evolution of the SSEs. This will aid in understanding the correlations between SSEs and seismicity and/or tremor and the role of SSEs in the accommodation of plate motion budgets in New Zealand.

Origin of the tail in Green's functions in odd-dimensional space-times

Science.gov (United States)

Dai, De-Chang; Stojkovic, Dejan

2013-10-01

It is well known that the scalar field Green's function in odd dimensions has a tail, i.e. a non-zero support inside the light cone, which in turn implies that the Huygens' principle is violated. However, the reason behind this behavior is still not quite clear. In this paper we shed more light on the physical origin of the tail by regularizing the term which is usually ignored in the literature since it vanishes due to the action of the delta function. With this extra term the Green's function does not satisfy the source-free wave equation (in the region outside of the source). We show that this term corresponds to a charge imprinted on the light-cone shell. Unlike the vector field charge, a moving scalar field charge is not Lorentz invariant and is contracted by a factor. If a scalar charge is moving at the speed of light, it appears to be zero in the static (with respect to the original physical charge) observer's frame. However, the field it sources is not entirely on the light cone. Thus, it is likely that this hidden charge sources the mysterious tail in odd dimensions.

Determination of malachite green and its leuco form in water

Science.gov (United States)

Allen, J.L.; Meinertz, J.R.; Gofus, J.E.

1992-01-01

Liquid chromatographic (lc) analysis can detect malachite green residues in water at less than 10 mu-g/l. Water samples were concentrated on disposable diol columns, eluted with 0.05m P-toluene-sulfonic acid in methanol, and determined by reversed-phase lc. When combined with a lead oxide postcolumn reactor, the lc method can simultaneously determine both leuco and chromatic forms of malachite green. Recoveries averaged 95.4% For the chromatic form and 57.3% For the leuco form of malachite green oxalate and leuco malachite green in spiked pond water samples. Recoveries of the carbinol form of malachite green (an equilibrium product of the dye in water) from spiked tap water samples averaged 98.6%. Recoveries of leuco malachite green were low and ph-dependent.

Mitigating and adapting to climate change: multi-functional and multi-scale assessment of green urban infrastructure.

Science.gov (United States)

Demuzere, M; Orru, K; Heidrich, O; Olazabal, E; Geneletti, D; Orru, H; Bhave, A G; Mittal, N; Feliu, E; Faehnle, M

2014-12-15

In order to develop climate resilient urban areas and reduce emissions, several opportunities exist starting from conscious planning and design of green (and blue) spaces in these landscapes. Green urban infrastructure has been regarded as beneficial, e.g. by balancing water flows, providing thermal comfort. This article explores the existing evidence on the contribution of green spaces to climate change mitigation and adaptation services. We suggest a framework of ecosystem services for systematizing the evidence on the provision of bio-physical benefits (e.g. CO2 sequestration) as well as social and psychological benefits (e.g. improved health) that enable coping with (adaptation) or reducing the adverse effects (mitigation) of climate change. The multi-functional and multi-scale nature of green urban infrastructure complicates the categorization of services and benefits, since in reality the interactions between various benefits are manifold and appear on different scales. We will show the relevance of the benefits from green urban infrastructures on three spatial scales (i.e. city, neighborhood and site specific scales). We will further report on co-benefits and trade-offs between the various services indicating that a benefit could in turn be detrimental in relation to other functions. The manuscript identifies avenues for further research on the role of green urban infrastructure, in different types of cities, climates and social contexts. Our systematic understanding of the bio-physical and social processes defining various services allows targeting stressors that may hamper the provision of green urban infrastructure services in individual behavior as well as in wider planning and environmental management in urban areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

Green's function for the scalar field in the early Universe

International Nuclear Information System (INIS)

Chowdhury, A.; Mallik, S.

1987-01-01

We derive the thermal Green's function for the scalar field in a de Sitter space-time and apply it to the problem of the early Universe. Field fluctuations relevant for inflation arise predominantly from wavelengths of the order of the inverse Hubble constant. Sufficient inflation is obtained in a Coleman-Weinberg model, provided the coupling constant is small enough. The results are insensitive to the choice of the vacuum of the field theory

Unitarity or asymptotic completeness equations and analytic structure of the S matrix and Green functions

International Nuclear Information System (INIS)

Iagolnitzer, D.

1983-11-01

Recent axiomatic results on the (non holonomic) analytic structure of the multiparticle S matrix and Green functions are reviewed and related general conjectures are described: (i) formal expansions of Green functions in terms of (holonomic) Feynman-type integrals in which each vertex represents an irreducible kernel, and (ii) ''graph by graph unitarity'' and other discontinuity formulae of the latter. These conjectures are closely linked with unitarity or asymptotic completeness equations, which they yield in a formal sense. In constructive field theory, a direct proof of the first conjecture (together with an independent proof of the second) would thus imply, as a first step, asymptotic completeness in that sense

Cryptochrome photoreceptors in green algae: Unexpected versatility of mechanisms and functions.

Science.gov (United States)

Kottke, Tilman; Oldemeyer, Sabine; Wenzel, Sandra; Zou, Yong; Mittag, Maria

2017-10-01

Green algae have a highly complex and diverse set of cryptochrome photoreceptor candidates including members of the following subfamilies: plant, plant-like, animal-like, DASH and cryptochrome photolyase family 1 (CPF1). While some green algae encode most or all of them, others lack certain members. Here we present an overview about functional analyses of so far investigated cryptochrome photoreceptors from the green algae Chlamydomonas reinhardtii (plant and animal-like cryptochromes) and Ostreococcus tauri (CPF1) with regard to their biological significance and spectroscopic properties. Cryptochromes of both algae have been demonstrated recently to be involved to various extents in circadian clock regulation and in Chlamydomonas additionally in life cycle control. Moreover, CPF1 even performs light-driven DNA repair. The plant cryptochrome and CPF1 are UVA/blue light receptors, whereas the animal-like cryptochrome responds to almost the whole visible spectrum including red light. Accordingly, plant cryptochrome, animal-like cryptochrome and CPF1 differ fundamentally in their structural response to light as revealed by their visible and infrared spectroscopic signatures, and in the role of the flavin neutral radical acting as dark form or signaling state. Copyright © 2017 Elsevier GmbH. All rights reserved.

Single-site Green function of the Dirac equation for full-potential electron scattering

Energy Technology Data Exchange (ETDEWEB)

Kordt, Pascal

2012-05-30

I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

Single-site Green function of the Dirac equation for full-potential electron scattering

International Nuclear Information System (INIS)

Kordt, Pascal

2012-01-01

I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

Multiscale simulations of anisotropic particles combining molecular dynamics and Green's function reaction dynamics

NARCIS (Netherlands)

Vijaykumar, A.; Ouldridge, T.E.; ten Wolde, P.R.; Bolhuis, P.G.

2017-01-01

The modeling of complex reaction-diffusion processes in, for instance, cellular biochemical networks or self-assembling soft matter can be tremendously sped up by employing a multiscale algorithm which combines the mesoscopic Green's Function Reaction Dynamics (GFRD) method with explicit stochastic

Rigorous derivation of the mean-field green functions of the two-band Hubbard model of superconductivity

International Nuclear Information System (INIS)

Adam, G.; Adam, S.

2007-01-01

The Green function (GF) equation of motion technique for solving the effective two-band Hubbard model of high-T c superconductivity in cuprates rests on the Hubbard operator (HO) algebra. We show that, if we take into account the invariance to translations and spin reversal, the HO algebra results in invariance properties of several specific correlation functions. The use of these properties allows rigorous derivation and simplification of the expressions of the frequency matrix (FM) and of the generalized mean-field approximation (GMFA) Green functions (GFs) of the model. For the normal singlet hopping and anomalous exchange pairing correlation functions which enter the FM and GMFA-GFs, the use of spectral representations allows the identification and elimination of exponentially small quantities. This procedure secures the reduction of the correlation order to the GMFA-GF expressions

Three-point Green's function of massless QED in position space to lowest order

International Nuclear Information System (INIS)

Mitra, Indrajit

2009-01-01

The transverse part of the three-point Green's function of massless QED is determined to the lowest order in position space. Taken together with the evaluation of the longitudinal part in Mitra (2008) (J. Phys. A: Math. Theor. 41 315401), this gives a relation for QED which is analogous to the star-triangle relation. We relate our result to conformal-invariant three-point functions

Long and short time quantum dynamics: I. Between Green's functions and transport equations

Czech Academy of Sciences Publication Activity Database

Špička, Václav; Velický, Bedřich; Kalvová, Anděla

2005-01-01

Roč. 29, - (2005), s. 154-174 ISSN 1386-9477 R&D Projects: GA ČR(CZ) GA202/04/0585; GA AV ČR(CZ) IAA1010404 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10100520 Keywords : non-equilibrium * Green functions * quantum transport * density functional the ory Subject RIV: BE - The oretical Physics Impact factor: 0.946, year: 2005

Empirical Green's function analysis: Taking the next step

Science.gov (United States)

Hough, S.E.

1997-01-01

An extension of the empirical Green's function (EGF) method is presented that involves determination of source parameters using standard EGF deconvolution, followed by inversion for a common attenuation parameter for a set of colocated events. Recordings of three or more colocated events can thus be used to constrain a single path attenuation estimate. I apply this method to recordings from the 1995-1996 Ridgecrest, California, earthquake sequence; I analyze four clusters consisting of 13 total events with magnitudes between 2.6 and 4.9. I first obtain corner frequencies, which are used to infer Brune stress drop estimates. I obtain stress drop values of 0.3-53 MPa (with all but one between 0.3 and 11 MPa), with no resolved increase of stress drop with moment. With the corner frequencies constrained, the inferred attenuation parameters are very consistent; they imply an average shear wave quality factor of approximately 20-25 for alluvial sediments within the Indian Wells Valley. Although the resultant spectral fitting (using corner frequency and ??) is good, the residuals are consistent among the clusters analyzed. Their spectral shape is similar to the the theoretical one-dimensional response of a layered low-velocity structure in the valley (an absolute site response cannot be determined by this method, because of an ambiguity between absolute response and source spectral amplitudes). I show that even this subtle site response can significantly bias estimates of corner frequency and ??, if it is ignored in an inversion for only source and path effects. The multiple-EGF method presented in this paper is analogous to a joint inversion for source, path, and site effects; the use of colocated sets of earthquakes appears to offer significant advantages in improving resolution of all three estimates, especially if data are from a single site or sites with similar site response.

A Note on Functional Averages over Gaussian Ensembles

Directory of Open Access Journals (Sweden)

Gabriel H. Tucci

2013-01-01

Full Text Available We find a new formula for matrix averages over the Gaussian ensemble. Let H be an n×n Gaussian random matrix with complex, independent, and identically distributed entries of zero mean and unit variance. Given an n×n positive definite matrix A and a continuous function f:ℝ+→ℝ such that ∫0∞‍e-αt|f(t|2dt0, we find a new formula for the expectation [Tr(f(HAH*]. Taking f(x=log(1+x gives another formula for the capacity of the MIMO communication channel, and taking f(x=(1+x-1 gives the MMSE achieved by a linear receiver.

Passive detection and localization of fatigue cracking in aluminum plates using Green's function reconstruction from ambient noise.

Science.gov (United States)

Yang, Yang; Xiao, Li; Qu, Wenzhong; Lu, Ye

2017-11-01

Recent theoretical and experimental studies have demonstrated that a local Green's function can be retrieved from the cross-correlation of ambient noise field. This technique can be used to detect fatigue cracking in metallic structures, owing to the fact that the presence of crack can lead to a change in Green's function. This paper presents a method of structural fatigue cracking characterization method by measuring Green's function reconstruction from noise excitation and verifies the feasibility of crack detection in poor noise source distribution. Fatigue cracks usually generate nonlinear effects, in which different wave amplitudes and frequency compositions can cause different nonlinear responses. This study also undertakes analysis of the capacity of the proposed approach to identify fatigue cracking under different noise amplitudes and frequency ranges. Experimental investigations of an aluminum plate are conducted to assess the cross-correlations of received noise between sensor pairs and finally to detect the introduced fatigue crack. A damage index is proposed according to the variation between cross-correlations obtained from the pristine crack closed state and the crack opening-closure state when sufficient noise amplitude is used to generate nonlinearity. A probability distribution map of damage is calculated based on damage indices. The fatigue crack introduced in the aluminum plate is successfully identified and oriented, verifying that a fatigue crack can be detected by reconstructing Green's functions from an imperfect diffuse field in which ambient noise sources exist locally. Copyright © 2017 Elsevier B.V. All rights reserved.

Noise Reduction for Nonlinear Nonstationary Time Series Data using Averaging Intrinsic Mode Function

Directory of Open Access Journals (Sweden)

Christofer Toumazou

2013-07-01

Full Text Available A novel noise filtering algorithm based on averaging Intrinsic Mode Function (aIMF, which is a derivation of Empirical Mode Decomposition (EMD, is proposed to remove white-Gaussian noise of foreign currency exchange rates that are nonlinear nonstationary times series signals. Noise patterns with different amplitudes and frequencies were randomly mixed into the five exchange rates. A number of filters, namely; Extended Kalman Filter (EKF, Wavelet Transform (WT, Particle Filter (PF and the averaging Intrinsic Mode Function (aIMF algorithm were used to compare filtering and smoothing performance. The aIMF algorithm demonstrated high noise reduction among the performance of these filters.

Improvements on non-equilibrium and transport Green function techniques: The next-generation TRANSIESTA

OpenAIRE

Papior, Nick Rübner; Lorente, Nicolás; Frederiksen, Thomas; García, Alberto; Brandbyge, Mads

2017-01-01

We present novel methods implemented within the non-equilibrium Green function code (NEGF) TRANSIESTA based on density functional theory (DFT). Our flexible, next-generation DFT–NEGF code handles devices with one or multiple electrodes (Ne≥1) with individual chemical potentials and electronic temperatures. We describe its novel methods for electrostatic gating, contour optimizations, and assertion of charge conservation, as well as the newly implemented algorithms for optimized and scalable m...

Green's Function and Stress Fields in Stochastic Heterogeneous Continua

Science.gov (United States)

Negi, Vineet

Many engineering materials used today are heterogenous in composition e.g. Composites - Polymer Matrix Composites, Metal Matrix Composites. Even, conventional engineering materials - metals, plastics, alloys etc. - may develop heterogeneities, like inclusions and residual stresses, during the manufacturing process. Moreover, these materials may also have intrinsic heterogeneities at a nanoscale in the form of grain boundaries in metals, crystallinity in amorphous polymers etc. While, the homogenized constitutive models for these materials may be satisfactory at a macroscale, recent studies of phenomena like fatigue failure, void nucleation, size-dependent brittle-ductile transition in polymeric nanofibers reveal a major play of micro/nanoscale physics in these phenomena. At this scale, heterogeneities in a material may no longer be ignored. Thus, this demands a study into the effects of various material heterogeneities. In this work, spatial heterogeneities in two material properties - elastic modulus and yield stress - have been investigated separately. The heterogeneity in the elastic modulus is studied in the context of Green's function. The Stochastic Finite Element method is adopted to get the mean statistics of the Green's function defined on a stochastic heterogeneous 2D infinite space. A study of the elastic-plastic transition in a domain having stochastic heterogenous yield stress was done using Mont-Carlo methods. The statistics for various stress and strain fields during the transition were obtained. Further, the effects of size of the domain and the strain-hardening rate on the stress fields during the heterogeneous elastic-plastic transition were investigated. Finally, a case is made for the role of the heterogenous elastic-plastic transition in damage nucleation and growth.

Green's functions for stress-intensity-factors for through cracks emanating from holes

International Nuclear Information System (INIS)

Bhandari, S.; Dubeaux, P.

1981-01-01

We conducted a parametric study of cracks at various elliptical openings in plates. We used five values of ellipticity and ten values of crack lengths at the edge of these holes. The computer program used is based on the Boundary Integral Equation method which requires only the contour of the structure to be segmented. The results concerning the stress distribution in the uncracked structure were verified for the cases where analytical results were available. Moreover the values of the S.I.F. for certain cases were checked through the use of some of the methods available in the literature. The final aim of this parametric study is to come up with simple Green's functions for cracks at holes. This has been possible through: (a) The use of the stress distribution in the uncracked structure (b) The Green's function for a crack in an infinite medium and (c) The principles underlying the Schwarz alternating technique used in the potential theory to resolve problems of finite regions. Finally the procedure is applied to treat a practical case of cracks as fastner holes. (orig.)

Green function formalism for nonlinear acoustic waves in layered media

International Nuclear Information System (INIS)

Lobo, A.; Tsoy, E.; De Sterke, C.M.

2000-01-01

Full text: The applications of acoustic waves in identifying defects in adhesive bonds between metallic plates have received little attention at high intensities where the media respond nonlinearly. However, the effects of reduced bond strength are more distinct in the nonlinear response of the structure. Here we assume a weak nonlinearity acting as a small perturbation, thereby reducing the problem to a linear one. This enables us to develop a specialized Green function formalism for calculating acoustic fields in layered media

The Green-function transform and wave propagation

Directory of Open Access Journals (Sweden)

Colin eSheppard

2014-11-01

Full Text Available Fourier methods well known in signal processing are applied to three-dimensional wave propagation problems. The Fourier transform of the Green function, when written explicitly in terms of a real-valued spatial frequency, consists of homogeneous and inhomogeneous components. Both parts are necessary to result in a pure out-going wave that satisfies causality. The homogeneous component consists only of propagating waves, but the inhomogeneous component contains both evanescent and propagating terms. Thus we make a distinction between inhomogeneous waves and evanescent waves. The evanescent component is completely contained in the region of the inhomogeneous component outside the k-space sphere. Further, propagating waves in the Weyl expansion contain both homogeneous and inhomogeneous components. The connection between the Whittaker and Weyl expansions is discussed. A list of relevant spherically symmetric Fourier transforms is given.

Green functions of graphene: An analytic approach

Energy Technology Data Exchange (ETDEWEB)

Lawlor, James A., E-mail: jalawlor@tcd.ie [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Ferreira, Mauro S. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); CRANN, Trinity College Dublin, Dublin 2 (Ireland)

2015-04-15

In this article we derive the lattice Green Functions (GFs) of graphene using a Tight Binding Hamiltonian incorporating both first and second nearest neighbour hoppings and allowing for a non-orthogonal electron wavefunction overlap. It is shown how the resulting GFs can be simplified from a double to a single integral form to aid computation, and that when considering off-diagonal GFs in the high symmetry directions of the lattice this single integral can be approximated very accurately by an algebraic expression. By comparing our results to the conventional first nearest neighbour model commonly found in the literature, it is apparent that the extended model leads to a sizeable change in the electronic structure away from the linear regime. As such, this article serves as a blueprint for researchers who wish to examine quantities where these considerations are important.

Use of Green functions in line shape problems in nuclear Magnetic resonance

International Nuclear Information System (INIS)

Martin, M.; Moreno, J.A.

1982-01-01

A method based on the two times Green function formalism is presented. It permits the straightforward determination of the line shape in Magnetic Resonance experiments together with its temperature behavior. Model calculations are made on a two-spin system attached to a one-dimensional rotor obtaining the temperature dependence of its Magnetic Resonance line shape and second moment

Numerical solution of the potential problem by integral equations without Green's functions

International Nuclear Information System (INIS)

De Mey, G.

1977-01-01

An integral equation technique will be presented to solve Laplace's equation in a two-dimensional area S. The Green's function has been replaced by a particular solution of Laplace equation in order to establish the integral equation. It is shown that accurate results can be obtained provided the pivotal elimination method is used to solve the linear algebraic set

Relation between Euclidean and real time calculations of Green functions at finite temperature

International Nuclear Information System (INIS)

Bochkarev, A.

1993-01-01

We find a relation between the semiclassical approximation of the temperature (Matsubara) two-point correlator and the corresponding classical Green function in real time at finite temperature. The anharmonic oscillator at finite temperature is used to illustrate our statement, which is however of rather general origin

Nonequilibrium Green function techniques applied to hot electron quantum transport

International Nuclear Information System (INIS)

Jauho, A.P.

1989-01-01

During the last few years considerable effort has been devoted to deriving quantum transport equations for semiconductors under extreme conditions (high electric fields, spatial quantization in one or two directions). Here we review the results obtained with nonequilibrium Green function techniques as formulated by Baym and Kadanoff, or by Keldysh. In particular, the following topics will be discussed: (i) Systematic approaches to reduce the transport equation governing the correlation function to a transport equation for the Wigner function; (ii) Approximations reducing the nonmarkovian quantum transport equation to a numerically tractable form, and results for model semiconductors; (iii) Recent progress in extending the formalism to inhomogeneous systems; and (iv) Nonequilibrium screening. In all sections we try to direct the reader's attention to points where the present understanding is (at best) incomplete, and indicate possible lines for future work. (orig.)

Towards green loyalty: the influences of green perceived risk, green image, green trust and green satisfaction

Science.gov (United States)

Chrisjatmiko, K.

2018-01-01

The paper aims to present a comprehensive framework for the influences of green perceived risk, green image, green trust and green satisfaction to green loyalty. The paper also seeks to account explicitly for the differences in green perceived risk, green image, green trust, green satisfaction and green loyalty found among green products customers. Data were obtained from 155 green products customers. Structural equation modeling was used in order to test the proposed hypotheses. The findings show that green image, green trust and green satisfaction has positive effects to green loyalty. But green perceived risk has negative effects to green image, green trust and green satisfaction. However, green perceived risk, green image, green trust and green satisfaction also seems to be a good device to gain green products customers from competitors. The contributions of the paper are, firstly, a more complete framework of the influences of green perceived risk, green image, green trust and green satisfaction to green loyalty analyses simultaneously. Secondly, the study allows a direct comparison of the difference in green perceived risk, green image, green trust, green satisfaction and green loyalty between green products customers.

Recursive evaluation of space-time lattice Green's functions

International Nuclear Information System (INIS)

De Hon, Bastiaan P; Arnold, John M

2012-01-01

Up to a multiplicative constant, the lattice Green's function (LGF) as defined in condensed matter physics and lattice statistical mechanics is equivalent to the Z-domain counterpart of the finite-difference time-domain Green's function (GF) on a lattice. Expansion of a well-known integral representation for the LGF on a ν-dimensional hyper-cubic lattice in powers of Z −1 and application of the Chu–Vandermonde identity results in ν − 1 nested finite-sum representations for discrete space-time GFs. Due to severe numerical cancellations, these nested finite sums are of little practical use. For ν = 2, the finite sum may be evaluated in closed form in terms of a generalized hypergeometric function. For special lattice points, that representation simplifies considerably, while on the other hand the finite-difference stencil may be used to derive single-lattice-point second-order recurrence schemes for generating 2D discrete space-time GF time sequences on the fly. For arbitrary symbolic lattice points, Zeilberger's algorithm produces a third-order recurrence operator with polynomial coefficients of the sixth degree. The corresponding recurrence scheme constitutes the most efficient numerical method for the majority of lattice points, in spite of the fact that for explicit numeric lattice points the associated third-order recurrence operator is not the minimum recurrence operator. As regards the asymptotic bounds for the possible solutions to the recurrence scheme, Perron's theorem precludes factorial or exponential growth. Along horizontal lattices directions, rapid initial growth does occur, but poses no problems in augmented dynamic-range fixed precision arithmetic. By analysing long-distance wave propagation along a horizontal lattice direction, we have concluded that the chirp-up oscillations of the discrete space-time GF are the root cause of grid dispersion anisotropy. With each factor of ten increase in the lattice distance, one would have to roughly

On the Reliability of Source Time Functions Estimated Using Empirical Green's Function Methods

Science.gov (United States)

Gallegos, A. C.; Xie, J.; Suarez Salas, L.

2017-12-01

The Empirical Green's Function (EGF) method (Hartzell, 1978) has been widely used to extract source time functions (STFs). In this method, seismograms generated by collocated events with different magnitudes are deconvolved. Under a fundamental assumption that the STF of the small event is a delta function, the deconvolved Relative Source Time Function (RSTF) yields the large event's STF. While this assumption can be empirically justified by examination of differences in event size and frequency content of the seismograms, there can be a lack of rigorous justification of the assumption. In practice, a small event might have a finite duration when the RSTF is retrieved and interpreted as the large event STF with a bias. In this study, we rigorously analyze this bias using synthetic waveforms generated by convolving a realistic Green's function waveform with pairs of finite-duration triangular or parabolic STFs. The RSTFs are found using a time-domain based matrix deconvolution. We find when the STFs of smaller events are finite, the RSTFs are a series of narrow non-physical spikes. Interpreting these RSTFs as a series of high-frequency source radiations would be very misleading. The only reliable and unambiguous information we can retrieve from these RSTFs is the difference in durations and the moment ratio of the two STFs. We can apply a Tikhonov smoothing to obtain a single-pulse RSTF, but its duration is dependent on the choice of weighting, which may be subjective. We then test the Multi-Channel Deconvolution (MCD) method (Plourde & Bostock, 2017) which assumes that both STFs have finite durations to be solved for. A concern about the MCD method is that the number of unknown parameters is larger, which would tend to make the problem rank-deficient. Because the kernel matrix is dependent on the STFs to be solved for under a positivity constraint, we can only estimate the rank-deficiency with a semi-empirical approach. Based on the results so far, we find that the

``Green's function'' approach & low-mode asymmetries

Science.gov (United States)

Masse, Laurent; Clark, Dan; Salmonson, Jay; MacLaren, Steve; Ma, Tammy; Khan, Shahab; Pino, Jesse; Ralph, Jo; Czajka, C.; Tipton, Robert; Landen, Otto; Kyrala, Georges; 2 Team; 1 Team

2017-10-01

Long wavelength, low mode asymmetries are believed to play a leading role in limiting the performance of current ICF implosions on NIF. These long wavelength modes are initiated and driven by asymmetries in the x-ray flux from the hohlraum; however, the underlying hydrodynamics of the implosion also act to amplify these asymmetries. The work presented here aim to deepen our understanding of the interplay of the drive asymmetries and the underlying implosion hydrodynamics in determining the final imploded configuration. This is accomplished through a synthesis of numerical modeling, analytic theory, and experimental data. In detail, we use a Green's function approach to connect the drive asymmetry seen by the capsule to the measured inflight and hot spot symmetries. The approach has been validated against a suite of numerical simulations. Ultimately, we hope this work will identify additional measurements to further constrain the asymmetries and increase hohlraum illumination design flexibility on the NIF. The technique and derivation of associated error bars will be presented. LLC, (LLNS) Contract No. DE-AC52-07NA27344.

Scheme for ab initio calculation of the Green function in large disordered systems with application to transport properties

Science.gov (United States)

Tanaka, Hiroshi

1998-01-01

A real-space scheme is developed to calculate matrix elements of the Green function from first principles for large disordered systems. The scheme is an extension of the particle source method, combined with the tight-binding linear muffin-tin orbitals and has the following advantages: (i) It is possible to evaluate both the diagonal and off-diagonal parts of the Green function and also their products with other quantum operators, (ii) it allows for an explicit control of the numerical accuracy and clear-cut physical interpretations of the results on the basis of the definition of the Green function, and (iii) the scheme is suitable for both vector and parallel processing and requires CPU time and memory size proportional only to the system size. The method is applied to the densities of states of bcc and amorphous Fe. The dc conductivity is also evaluated for the latter from the Kubo-Greenwood formula.

Spin-hydrodynamic equations with external disturbances and suitable Green's functions for superfluid 3He-B. New Onsager relations

International Nuclear Information System (INIS)

Galasiewicz, Z.M.

1984-01-01

The spin-hydrodynamic equations for superfluid 3 He-B are obtained for the case of external, time-dependent fields. On the basis of a microscopic approach, expressions are found for additional terms in equations containing these fields. Considering the linear response of the system to the switching on of external fields, formulas are found for suitable Green's functions (magnetization-magnetization, rotation-rotation, magnetization-rotation , rotation-magnetization). The rotation-rotation Green's function has the 1/q 2 singularity characteristic of superfluid systems. Connections between Green's functions lead to relations among kinetic coefficients nu, μ 1 , and μ 2 . It is also shown that there is a conserved quantity Q/sup (B)/ = div nu/sub s//sup (B)/ that describes sources or magnetic type charges (monopoles) of the superfluid velocity nu/sub s//sup (B)/. Comparison with the phenomenological approach suggests that Q/sup (B)/ is proportional to a pseudoscalar giving the projection of the spin density onto the vector describing that axis of rotation. 14 references

Transient difference solutions of the inhomogeneous wave equation - Simulation of the Green's function

Science.gov (United States)

Baumeister, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Transient difference solutions of the inhomogeneous wave equation: Simulation of the Green's function

Science.gov (United States)

Baumeiste, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Green's function method with consideration of temperature dependent material properties for fatigue monitoring of nuclear power plants

International Nuclear Information System (INIS)

Koo, Gyeong-Hoi; Kwon, Jong-Jooh; Kim, Wanjae

2009-01-01

In this paper, a method to consider temperature dependent material properties when using the Green's function method is proposed by using a numerical weight function approach. This is verified by using detailed finite element analyses for a pressurizer spray nozzle with various assumed thermal transient load cases. From the results, it is found that the temperature dependent material properties can significantly affect the maximum peak stresses and the proposed method can resolve this problem with the weight function approach. Finally, it is concluded that the temperature dependency of the material properties affects the maximum stress ranges for a fatigue evaluation. Therefore, it is necessary to consider this effect to monitor fatigue damage when using a Green's function method for the real operating conditions in a nuclear power plant

Generation of data base for on-line fatigue life monitoring of Indian nuclear power plant components: Part I - Generation of Green's functions for end fitting

International Nuclear Information System (INIS)

Mukhopadhyay, N.K.; Dutta, B.K.; Kushwaha, H.S.

1994-01-01

Green's function technique is the heart of the on- line fatigue monitoring methodology. The plant transients are converted to stress and temperature response using this technique. To implement this methodology in a nuclear power plant, Green's functions are to be generated in advance. For structures of complex geometries, Green's functions are to be stored in a data base to convert on-line, the plant data to temperature/stress response, using a personal computer. End fitting, end shield, pressurizer, steam generator tube sheet are few such components of PHWR where fatigue monitoring is needed. In the present paper, Green's functions are generated for end fitting of a 235 MWe Indian PHWR using finite element method. End fitting has been analysed using both 3-D and 2-D (axisymmetric) finite element models. Temperature and stress Green's functions are generated at few critical locations using the code ABAQUS. (author). 10 refs., 11 figs

An algebraic construction of the Green functions for P(φ)2 theory with source

International Nuclear Information System (INIS)

Houard, J.C.; Irac-Astaud, M.

1987-01-01

The retarded solutions of nonlinear forced wave equations in two-dimensional space-time are diagrammatically expanded in a new way, different from the Feynman method. The Green functions associated with these diagrams are obtained in an explicit form. (author). 4 refs

Quantum field theory in non-stationary coordinate systems and Green functions

International Nuclear Information System (INIS)

Svaiter, B.F.; Svaiter, N.F.

1988-01-01

In this paper we studied a neutral massive scalar field in a bi-dimensional Milne space time. The quantization is made on hyperboles which are Lorentz invariant surfaces. The expansion for the field operator was carried on using a complete set of orthonormal modes which have definite positive and negative dilatation frequence. We have calculated the advanced and retarded Green function and proved that the Feynman propagator diverges in the usual sense. (author) [pt

Progress in Non-equilibrium Green's Functions (PNGF VI)

International Nuclear Information System (INIS)

2016-01-01

The sixth interdisciplinary conference 'Progress in Non-equilibrium Green's Functions' (PNGF6) took place at Lund University, Sweden, on 17-21 August 2015. The conference was attended by 60 scientists, from Europe and overseas, sharing an interest in Green's function methods and/or non-equilibrium phenomena. At the conference, 34 invited and contributed talks were given, together with a poster session with 17 contributions. As its predecessors (Rostock 1999, Dresden 2002, Kiel 2005, Glasgow 2009, Jyväskylä 2012) did, the conference succeeded in gathering different communities for the exchange of recent developments and results. Among the topics of the conference, we mention approaches for strongly correlated systems, improvements of existing perturbative many-body schemes, electron-phonon/-photon interactions in time-dependent treatments, numerical scalability of NEGF approaches, connections with other non-equilibrium methods and concrete physical applications. For the latter, we mention quantum transport, semiconductor kinetics, multiply excited states in atoms and ions, nuclear reactions, high energy physics, quantum cascade lasers, strongly correlated model systems, graphene-nanostructures, optoelectronics, superconductors, spin-dynamics, photovoltaics, excitations in atoms and ions and time-resolved spectroscopy. The present volume contains 20 articles from participants of PNGF6, devoted to these topics. Compared to previous conferences, a completely novel and successful aspect of PNGF6 was the participation of experimentalists among the invited speakers, to establish a connection between emerging experimental techniques (for example, time-dependent spectroscopies) and the theoretical NEGF community. As at the previous PNGF conferences, the atmosphere was friendly and exciting at the same time, favoring vivid and stimulating discussions among experienced scientists, young researchers and students. The conference would not have been

Allometric scaling of kidney function in green iguanas.

Science.gov (United States)

Maxwell, Lara K; Jacobson, Elliott R

2004-07-01

Numerous physiological parameters, such as metabolic rate and glomerular filtration rate (GFR), are allometrically related to body mass. Whereas the interspecific relationships between metabolic rate and body mass have been extensively studied in vertebrates, intraspecific studies of renal function have been limited. Therefore, kidney function was studied in 16 green iguanas, (Iguana iguana; 322-4764 g), by using nuclear scintigraphy to measure the renal uptake of 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA), following either intravenous or intraosseous administration. Route of 99mTc-DTPA administration did not affect the percentage of the dose that accumulated in the kidney (P > 0.05). Renal uptake of 99mTc-DTPA was related to body mass (W, g) as: %Dose Kidney (min-1) = 11.09W(-0.235). Although not directly measured, the apparent renal clearance of 99mTc-DTPA could be described as: Renal CL 99mTc-DTPA (ml.min-1) = 0.005W(0.759), and the mass exponent did not differ from either the 2/3 or 3/4 values (P > 0.05). The similarity of the mass exponents relating both renal function and metabolic rate to body mass suggests a common mechanism underlying these allometric relationships. As this study also demonstrated that renal scintigraphy can be used to quantify kidney function in iguanas, this technique may be a useful research and diagnostic tool.

Green channel cargo inspection system

International Nuclear Information System (INIS)

Shi Yuanping; Yu Jingsheng; Sun Hongqiang; Hao Pu; Cai Wenxia

2011-01-01

A radiation detection device was installed in the lanes of a highway toll station, radioactive rays which was collimated emitted through the measured, and arrived the detector. The average density of the fresh agricultural products belonged to Green channel and other prohibited items vary greatly, the absorption of radiation are different between the Green Channel Cargo and other substances. Prior to the experimental group, different standard samples which represent different models and goods were measured, the different standard samples were stored in a computer database. When the trucks get through the Green Channel, the detector will detect the radiation signal and bring to the computer, the computer will process the measured data, and make a conclusion whether the goods are Green Channel cargo. (authors)

Green nesting material has a function in mate attraction in the European starling

NARCIS (Netherlands)

Komdeur, J

The function of fresh green nest material has long been debated. It has been suggested that it reduces the number of ectoparasites in nests and on nestlings (nest protection hypothesis), or is used by males to signal condition and paternal quality (male quality hypothesis) or is used as a sexually

The Application of Neutron Transport Green's Functions to Threat Scenario Simulation

Science.gov (United States)

Thoreson, Gregory G.; Schneider, Erich A.; Armstrong, Hirotatsu; van der Hoeven, Christopher A.

2015-02-01

Radiation detectors provide deterrence and defense against nuclear smuggling attempts by scanning vehicles, ships, and pedestrians for radioactive material. Understanding detector performance is crucial to developing novel technologies, architectures, and alarm algorithms. Detection can be modeled through radiation transport simulations; however, modeling a spanning set of threat scenarios over the full transport phase-space is computationally challenging. Previous research has demonstrated Green's functions can simulate photon detector signals by decomposing the scenario space into independently simulated submodels. This paper presents decomposition methods for neutron and time-dependent transport. As a result, neutron detector signals produced from full forward transport simulations can be efficiently reconstructed by sequential application of submodel response functions.

Inverse electronic scattering by Green's functions and singular values decomposition

International Nuclear Information System (INIS)

Mayer, A.; Vigneron, J.-P.

2000-01-01

An inverse scattering technique is developed to enable a sample reconstruction from the diffraction figures obtained by electronic projection microscopy. In its Green's functions formulation, this technique takes account of all orders of diffraction by performing an iterative reconstruction of the wave function on the observation screen. This scattered wave function is then backpropagated to the sample to determine the potential-energy distribution, which is assumed real valued. The method relies on the use of singular values decomposition techniques, thus providing the best least-squares solutions and enabling a reduction of noise. The technique is applied to the analysis of a two-dimensional nanometric sample that is observed in Fresnel conditions with an electronic energy of 25 eV. The algorithm turns out to provide results with a mean relative error of the order of 5% and to be very stable against random noise

Green's function approach to the anisotropic Kondo-necklace lattice

International Nuclear Information System (INIS)

Rezania, H.; Langari, A.; Thalmeier, P.

2007-01-01

Full text: We have studied the effect of anisotropy on the quantum phase transition of the 2D anisotropic Kondo necklace lattice [1] within a Green's function approach [2]. In the disordered phase the ground state is the product of all singlet bonds between itinerant and localized spins. It is separated by a finite energy gap from the triplet excited states. The quantum phase transition to the antiferromagnetically ordered phase takes place where the gap vanishes. In this approach we use the bond operator formalism introduced in Ref.[3] where each bond is represented by the singlet and triplet operators. The Kondo necklace Hamiltonian in the bond operator representation is composed of the kinetic energy and pairing part (H2), the two particle interaction (H4) of the boson gas and a term which includes three boson operators (H3). In order to ensure that the physical states are either singlets or triplets we impose the hard-core condition by introducing an infinite on-site repulsion between triplet bosons (H U ). The scattering vertex in the ladder approximation satisfies the Bethe-Salpeter equation [4]. By calculating the scattering vertex function we obtain the self energy contribution of the Hamiltonian H U . We have added the second order contribution of the self energy of H3 to the self energy of H U . It should be noted that the non conservation of triplet boson numbers requires the inclusion of the anomalous Green's functions. We treat H 4 in mean-field theory, by splitting the quartic operator into all possible pairs. Finally we obtain the renormalization of coefficients in the H 2 Hamiltonian and calculate the energy gap. Indeed at the critical point a condensation of triplet bosons occurs. We have numerically found the critical point of this model and compared our results with the corresponding mean field values [5]. Moreover, the critical exponent of the energy gap can be obtained more accurately than the mean field results. (authors)

Green's functions for a scalar fields in a class of Robertson-Walker space-times

International Nuclear Information System (INIS)

Mankin, Romi; Ainsaar, Ain

1997-01-01

The retarded and advanced Green's functions for a massless non conformally-coupled scalar field in a class of Robertson-Walker space-times are calculated analytically. The results are applied to the calculation of the Hadamard fundamental solutions in some special cases. (author)

The Green-Kubo formula, autocorrelation function and fluctuation spectrum for finite Markov chains with continuous time

International Nuclear Information System (INIS)

Chen Yong; Chen Xi; Qian Minping

2006-01-01

A general form of the Green-Kubo formula, which describes the fluctuations pertaining to all the steady states whether equilibrium or non-equilibrium, for a system driven by a finite Markov chain with continuous time (briefly, MC) {ξ t }, is shown. The equivalence of different forms of the Green-Kubo formula is exploited. We also look at the differences in terms of the autocorrelation function and the fluctuation spectrum between the equilibrium state and the non-equilibrium steady state. Also, if the MC is in the non-equilibrium steady state, we can always find a complex function ψ, such that the fluctuation spectrum of {φ(ξ t )} is non-monotonous in [0, + ∞)

Urban area and green space: volume estimation using medium resolution satellite imagery

Science.gov (United States)

Handayani, H. H.

2017-12-01

The latest revision of the UN World Urbanization Prospects predicts the world's urban population to increase by 1.4 billion between 2010 and 2030, 60% of the population will live in cities. Consequently, this expansion affects the existence of ecosystem services in the context of sustainability environment. Green space is a focal point of the ecological system and is affected by the urbanization process. The green space has essential functions in cleaning the water, adjusting the microclimate, eliminating noise, and beautifying the surrounding makes the green quantity as well as quality very vital to its existence. The urban expansion leads the growth into vertical development. Therefore, the third dimension using urban volume as an indicator of vertical development is introduced. Therefore, this study estimates the urban and green volume by using medium resolution remote sensing. Surabaya is used as a case study since the city has grown up significantly in both of population and capital investment in this decade. Here, urban and green volume is investigated by ALOS datasets with urban referring built-up. Also, we examine the area with low and high green volume by performing hot and cold spots analysis. The average of built-up volume reaches 173.05 m3/pixel presented by the building for a residential single house with the height less than 7m. The average of green volume is 14.74m3/pixel performed by the vegetation with the height generally 0.6 to 1m which is frequently planted in the backyard of house. However, the ratio of green volume to the built-up volume shows a small portion which is around 8.52%. Therefore, we identify the hot and cold spots, we evaluate 5 areas having cold spot regarding lack of green volume. The two locations of cold spot are located in the northern part and another is in the southern part. Those areas have high number of built-up volume which is in particularly as sub-CBD area. We emphasize that the improvement of green quantity is needed

The effect of urban green on small-area (healthy) life expectancy.

Science.gov (United States)

Jonker, M F; van Lenthe, F J; Donkers, B; Mackenbach, J P; Burdorf, A

2014-10-01

Several epidemiological studies have investigated the effect of the quantity of green space on health outcomes such as self-rated health, morbidity and mortality ratios. These studies have consistently found positive associations between the quantity of green and health. However, the impact of other aspects, such as the perceived quality and average distance to public green, and the effect of urban green on population health are still largely unknown. Linear regression models were used to investigate the impact of three different measures of urban green on small-area life expectancy (LE) and healthy life expectancy (HLE) in The Netherlands. All regressions corrected for average neighbourhood household income, accommodated spatial autocorrelation, and took measurement uncertainty of LE, HLE as well as the quality of urban green into account. Both the quantity and the perceived quality of urban green are modestly related to small-area LE and HLE: an increase of 1 SD in the percentage of urban green space is associated with a 0.1-year higher LE, and, in the case of quality of green, with an approximately 0.3-year higher LE and HLE. The average distance to the nearest public green is unrelated to population health. The quantity and particularly quality of urban green are positively associated with small-area LE and HLE. This concurs with a growing body of evidence that urban green reduces stress, stimulates physical activity, improves the microclimate and reduces ambient air pollution. Accordingly, urban green development deserves a more prominent place in urban regeneration and neighbourhood renewal programmes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The infinite medium Green's function for neutron transport in plane geometry 40 years later

International Nuclear Information System (INIS)

Ganapol, B.D.

1993-01-01

In 1953, the first of what was supposed to be two volumes on neutron transport theory was published. The monograph, entitled open-quotes Introduction to the Theory of Neutron Diffusionclose quotes by Case et al., appeared as a Los Alamos National Laboratory report and was to be followed by a second volume, which never appeared as intended because of the death of Placzek. Instead, Case and Zweifel collaborated on the now classic work entitled Linear Transport Theory 2 in which the underlying mathematical theory of linear transport was presented. The initial monograph, however, represented the coming of age of neutron transport theory, which had its roots in radiative transfer and kinetic theory. In addition, it provided the first benchmark results along with the mathematical development for several fundamental neutron transport problems. In particular, one-dimensional infinite medium Green's functions for the monoenergetic transport equation in plane and spherical geometries were considered complete with numerical results to be used as standards to guide code development for applications. Unfortunately, because of the limited computational resources of the day, some numerical results were incorrect. Also, only conventional mathematics and numerical methods were used because the transport theorists of the day were just becoming acquainted with more modern mathematical approaches. In this paper, Green's function solution is revisited in light of modern numerical benchmarking methods with an emphasis on evaluation rather than theoretical results. The primary motivation for considering the Green's function at this time is its emerging use in solving finite and heterogeneous media transport problems

Ergodic averages for monotone functions using upper and lower dominating processes

DEFF Research Database (Denmark)

Møller, Jesper; Mengersen, Kerrie

We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary...... Markov chain and we eliminate the problem of whether an appropriate burn-in is determined or not. Moreover, when a central limit theorem applies, we show how confidence intervals for the mean can be estimated by bounding the asymptotic variance of the ergodic average based on the equilibrium chain. Our...... methods are studied in detail for three models using Markov chain Monte Carlo methods and we also discuss various types of other models for which our methods apply....

Ergodic averages for monotone functions using upper and lower dominating processes

DEFF Research Database (Denmark)

Møller, Jesper; Mengersen, Kerrie

2007-01-01

We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary...... Markov chain and we eliminate the problem of whether an appropriate burn-in is determined or not. Moreover, when a central limit theorem applies, we show how confidence intervals for the mean can be estimated by bounding the asymptotic variance of the ergodic average based on the equilibrium chain. Our...... methods are studied in detail for three models using Markov chain Monte Carlo methods and we also discuss various types of other models for which our methods apply....

Why Green Taxation

DEFF Research Database (Denmark)

Hjøllund, Lene; Svendsen, Gert Tinggaard

2001-01-01

According to economists solving environmental problems is simple. Politicians should simply impose a uniform tax on harmful emissions. However, the actual design of such green taxation shows that politicians do not follow their advice. CO2 taxation in OECD, for example, is highly differentiated...... and much in favour of industry. In fact, CO2 tax rates for industry are, on average, six times lower than those for households. We argue that the reason for this tax differentiation is that industry, in contrast to households, has a strong capability to lobby. Therefore, green taxation is effectively...... blocked and the desired environmental results are not being achieved. Why then is green taxation persistently applied in relation to industry? We argue that strong fiscal incentives drive this policy choice at the expense of environmental concerns because it allows environmental bureaucracies to budget-maximize....

An Application of Green Quality Function Deployment to Designing an Air Conditioner

OpenAIRE

Peetam Kumar Dehariya; Dr. Devendra Singh Verma

2015-01-01

The paper tackles a systematic and operational approach to Green Quality Function Deployment (GQFD), a customer oriented survey based quality management system with regular improvement in product development. GQFD shows balance between product development and environmental protection. GQFD is not used to determine their attributes and their levels. GQFD captures what product developers “think” would best satisfy customer needs considering Environmental factor. This research used A...

Real-time traffic signal optimization model based on average delay time per person

Directory of Open Access Journals (Sweden)

Pengpeng Jiao

2015-10-01

Full Text Available Real-time traffic signal control is very important for relieving urban traffic congestion. Many existing traffic control models were formulated using optimization approach, with the objective functions of minimizing vehicle delay time. To improve people’s trip efficiency, this article aims to minimize delay time per person. Based on the time-varying traffic flow data at intersections, the article first fits curves of accumulative arrival and departure vehicles, as well as the corresponding functions. Moreover, this article transfers vehicle delay time to personal delay time using average passenger load of cars and buses, employs such time as the objective function, and proposes a signal timing optimization model for intersections to achieve real-time signal parameters, including cycle length and green time. This research further implements a case study based on practical data collected at an intersection in Beijing, China. The average delay time per person and queue length are employed as evaluation indices to show the performances of the model. The results show that the proposed methodology is capable of improving traffic efficiency and is very effective for real-world applications.

Green roofs and the LEED green building rating system

Energy Technology Data Exchange (ETDEWEB)

Kula, R. [Sustainable Solutions Inc., Wagoner, OK (United States)

2005-07-01

The sustainable building industry is becoming increasingly aware of the host of public and private benefits that green roofs can provide in built environments. In dense urban environments, green roofs function to reduce stormwater runoff, urban heat island effects, and particulate matter (PM) pollution. The emerging green roof industry is now poised to support the efforts of green building networks in North America. This paper discussed the general benefits of green roofs, and their recognition within the Leadership in Energy and Environmental Design (LEED) Green Building Rating System. A case study of Mountain Equipment Co-op's Winnipeg site was presented. The building's green roof was directly responsible for earning 5 credits and contributing to the achievement of an additional 2 credits under the LEEDS certification process. Credits were earned for reduced site disturbance; landscape design to reduce heat islands; and water efficiency. The green roof at the site provided the vast majority of the building's cooling needs through an evaporative cooling trough. A photovoltaic pump was used to feed the building's irrigation system, as well as to pump ground water through cooling valances. It was concluded that the rise of sustainable building practices and the LEED Green Building Rating System will revolutionize the way new buildings are constructed.

Current experience concerning Romanian green certificates market functioning

International Nuclear Information System (INIS)

Vladescu, Gherghina; Lupului, Luminita; Vasilevschi, Constantin; Ghinea, Smaranda

2006-01-01

The renewable energy sources are promoted by their beneficial use, namely: - diversification of energy sources for producing electric power; - reduction of pollution produced by fossil fuel burning; - reduction of gas releases producing the greenhouse effects, etc. Currently, most of the renewable energy sources cannot concur on electric power free market because of the high costs of implied investments. To ensure an efficient use of renewable energy sources in electricity production and to maintain the installations implied on the electric power market, it is necessary to implement a system able to produce an output greater than that obtained from electric energy selling. The Romanian Government chose to promote the electric energy production by renewable energy sources by using the green certificate trading system. This system ensures the progress in developing the technologies employed in electric energy production from renewable energy sources and, at the same time the costs implied by their promotion can be adjusted by market mechanisms what will reduce the effects upon the electric energy consumers. The paper presents the legislation frame existing in Romania for promoting the electric energy produced from renewable energy sources, the green certificate trading system applied in Romania, as well as, the role shared by the entities implied in operation and development of the system. In November 2005, a first transaction with green certificates on controlled green certificate market in Romania took place. Analyzed is the evolution of the green certificate market registered so far from its inception, as well as, the lessons learned so far from the experience acquired

Application of the Green's function method for 2- and 3-dimensional steady transonic flows

Science.gov (United States)

Tseng, K.

1984-01-01

A Time-Domain Green's function method for the nonlinear time-dependent three-dimensional aerodynamic potential equation is presented. The Green's theorem is being used to transform the partial differential equation into an integro-differential-delay equation. Finite-element and finite-difference methods are employed for the spatial and time discretizations to approximate the integral equation by a system of differential-delay equations. Solution may be obtained by solving for this nonlinear simultaneous system of equations in time. This paper discusses the application of the method to the Transonic Small Disturbance Equation and numerical results for lifting and nonlifting airfoils and wings in steady flows are presented.

Soil-structure interaction analysis by Green function

International Nuclear Information System (INIS)

Muto, Kiyoshi; Kobayashi, Toshio; Nakahara, Mitsuharu.

1985-01-01

Using the method of discretized Green function which had been suggested by the authors, the parametric study of the effects of base mat foundation thickness and soil stiffness were conducted. There was no upper structure effects from the response and reaction stress of the soil by employing different base mat foundation thicknesses. However, the response stress of base mat itself had considerable effect on the base mat foundation stress. The harder the soil, became larger accelerations, and smaller displacements on the upper structure. The upper structure lines of force were directed onto the soil. In the case of soft soil, the reaction soil stress were distributed evenly over the entire reactor building area. Common characteristics of all cases, in-plane shear deformation of the upper floor occured and in-plane acceleration and displacement at the center of the structure become larger. Also, the soil stresses around the shield wall of the base mat foundation became large cecause of the effect of the shield wall bending. (Kubozono, M.)

Semi-analytical wave functions in relativistic average atom model for high-temperature plasmas

International Nuclear Information System (INIS)

Guo Yonghui; Duan Yaoyong; Kuai Bin

2007-01-01

The semi-analytical method is utilized for solving a relativistic average atom model for high-temperature plasmas. Semi-analytical wave function and the corresponding energy eigenvalue, containing only a numerical factor, are obtained by fitting the potential function in the average atom into hydrogen-like one. The full equations for the model are enumerated, and more attentions are paid upon the detailed procedures including the numerical techniques and computer code design. When the temperature of plasmas is comparatively high, the semi-analytical results agree quite well with those obtained by using a full numerical method for the same model and with those calculated by just a little different physical models, and the result's accuracy and computation efficiency are worthy of note. The drawbacks for this model are also analyzed. (authors)

Quantum field theory in the presence of a medium: Green's function expansions

Energy Technology Data Exchange (ETDEWEB)

Kheirandish, Fardin [Department of Physics, Islamic Azad University, Shahreza-Branch, Shahreza (Iran, Islamic Republic of); Salimi, Shahriar [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2011-12-15

Starting from a Lagrangian and using functional-integration techniques, series expansions of Green's function of a real scalar field and electromagnetic field, in the presence of a medium, are obtained. The parameter of expansion in these series is the susceptibility function of the medium. Relativistic and nonrelativistic Langevin-type equations are derived. Series expansions for Lifshitz energy in finite temperature and for an arbitrary matter distribution are derived. Covariant formulations for both scalar and electromagnetic fields are introduced. Two illustrative examples are given.

Green roofs; Les toitures vegetalisees

Energy Technology Data Exchange (ETDEWEB)

Seghier, C.

2006-03-15

Impervious surface coverage keeps spreading in cities. Streets, sidewalks, parking lots and roofs are waterproof, meaning greater amounts of water to channel and treat and higher flood risks during heavy rainfalls. Green roofing can play a key part in addressing this alarming issue. There are three types of green roofs: extensive, semi-intensive and intensive. The extensive green roof technique uses a thin soil covering with a variety of species providing year-round plant coverage. The plants are not necessarily horticultural in which case routine maintenance is minimal. No watering is needed. Usually extensive green roofs create an ecosystem. The semi-intensive green roof technique uses a soil covering of average thickness and serves to create decorative roofing. Although maintenance is moderate, watering is essential. The intensive green roof technique produces a terrace roof garden. Another advantage of green roofs is they increase the life cycle of the sealing. Roof sealing protection may see the span of its life cycle, now at about fifteen years, doubled if the building has a green roof. planning professionals still know very little about green roofing solutions. Yet, green roofing provides unquestionable ecological qualities and thermal and acoustic performance that have proven to be environmentally friendly. Yet France lags behind northern European countries in green roofing. The Germans, Swiss, Austrians, Scandinavians and Dutch have been using the technique for more than twenty years. (A.L.B.)

PENERAPAN KONSEP BANGUNAN RAMAH LINGKUNGAN MELALUI KONSTRUKSI GREEN PANEL SEBAGAI ALTERNATIF PENINGKATAN KENYAMANAN DALAM RUANG

Directory of Open Access Journals (Sweden)

Fitriyah Nurul Hidayati Utami

2008-12-01

Full Text Available Warmer air condition as the impact of global warming had effect to human bulding scale, i.e. the increasing of room temperature (T and relative humidity (RH. It causes an uncomfortable situation inside one building without using mechanical controlling temperature equipment, such as air conditioner (AC. Therefore, there is an alternative to improve indoor amenity by using green panel construction which appropriate with green building concept. The terninology of green panel in this research was designated a panel made by an iron material, which as a function as secondary skin (second layer that protect room inside from direct solar radiation, and also as an attempt for green building, or as a media for liana-plant growing. This research was conducted in Departemnr of Landscafe Architecture (DLA Class Room and its Corridor (Wing 13, Level VI. As a comparison location was General Laboratory which is managed by Departement of Agronomy and Horticulture (DAH located in the same wing and level, and DAH’s seminar room in the same level, but it antother wing. The effect of micro climate (T and RH in DLA’s Class Room were showed from the value of Temperature Humidity Index (THI around 25.7 to 30.6, with average 28.1 which is categorized as uncomfortable zone. The THI of DLA’s Class Room were about 25.7-27.1 (in the morning, 25.8-29.3 (in the afternoon and 25.8-30.6 (in the evening. Amenity level (THI value of DLA’s Class Room after green panel constructions were changed to 25.4 until 30.2 with average 27.7 which is still in uncomfortable category. However, THI value in the morning was in comportable category. If green panel coverage’s reach 100% the average THI value will decrease to comportable category (THI 21.0-27.0. The result of SBE test shows that the SBE value has positive correlation with green panel construction. Four photos with the highest SBE’s value were the photo after green panel constructed. This mean the construction of green

Planning multifunctional green infrastructure for compact cities

DEFF Research Database (Denmark)

Hansen, Rieke; Olafsson, Anton Stahl; van der Jagt, Alexander P.N.

2018-01-01

green space functions or the purposive design and management of multifunctional parks. Based on the findings, we arrive at five recommendations for promoting multifunctional urban green infrastructure in densifying urban areas: 1) undertake systematic spatial assessments of all urban green (and blue....... Further, spatial assessment, strategic planning and site design need to 4) consider synergies, trade-offs and the capacity of urban green spaces to provide functions as part of the wider green infrastructure network; and 5) largely benefit from cooperation between different sectors and public departments......Urban green infrastructure planning aims to develop green space networks on limited space in compact cities. Multifunctionality is considered key to achieving this goal as it supports planning practice that considers the ability of green spaces to provide multiple benefits concurrently. However...

Electromagnetic fields and Green functions in elliptical vacuum chambers

CERN Document Server

AUTHOR|(CDS)2084216; Biancacci, Nicolo; Migliorati, Mauro; Palumbo, Luigi; Vaccaro, Vittorio; CERN. Geneva. ATS Department

2017-01-01

In this paper, we discuss the electromagnetic interaction between a point charge travelling inside a waveguide of elliptical cross section, and the waveguide itself. By using a convenient expansion of the Mathieu functions, useful in particular for treating a variety of problems in applied mathematics and physics with elliptic geometry, we first obtain the longitudinal electromagnetic field of a point charge (Green function) in free space in terms of elliptical coordinates. This expression allows, then, to calculate the scattered field due to the boundary conditions in our geometry. By summing the contribution of the direct or primary field and the indirect field scattered by the boundary, after a careful choice of some expansion expressions, we derive a novel formula of the longitudinal electric field, in any transverse position of the elliptical cross section, generated by the charge moving along the longitudinal axis of the waveguide. The obtained expression is represented in a closed form, it can be diffe...

The Green-Kubo formula, autocorrelation function and fluctuation spectrum for finite Markov chains with continuous time

Energy Technology Data Exchange (ETDEWEB)

Chen Yong; Chen Xi; Qian Minping [School of Mathematical Sciences, Peking University, Beijing 100871 (China)

2006-03-17

A general form of the Green-Kubo formula, which describes the fluctuations pertaining to all the steady states whether equilibrium or non-equilibrium, for a system driven by a finite Markov chain with continuous time (briefly, MC) {l_brace}{xi}{sub t}{r_brace}, is shown. The equivalence of different forms of the Green-Kubo formula is exploited. We also look at the differences in terms of the autocorrelation function and the fluctuation spectrum between the equilibrium state and the non-equilibrium steady state. Also, if the MC is in the non-equilibrium steady state, we can always find a complex function {psi}, such that the fluctuation spectrum of {l_brace}{phi}({xi}{sub t}){r_brace} is non-monotonous in [0, + {infinity})

Infrared divergences of Green functions and renormalization in massless theories. 2

International Nuclear Information System (INIS)

Anikin, S.A.; Zav'yalova, O.I.; Karchev, N.I.

1981-01-01

General theorems are proved concerning the infrared finiteness of Green functions in theories including massless particles. Considerations are based on α-representation of Feynman diagrams. Necessory conditions are considered for proving theorems in the case of diagrams with massive lines. Under certain conditions the contribution of the considered sections into the Feynman amplitude is shown to be free from infrared divergences, but only for those subgraphs which involve all the massive lines and contain all the outer vertexes in one affinity component

Carrier transport in THz quantum cascade lasers: Are Green's functions necessary?

International Nuclear Information System (INIS)

Matyas, A; Jirauschek, C; Kubis, T; Lugli, P

2009-01-01

We have applied two different simulation models for the stationary carrier transport and optical gain analysis in resonant phonon depopulation THz Quantum Cascade Lasers (QCLs), based on the semiclassical ensemble Monte Carlo (EMC) and fully quantum mechanical non-equilibrium Green's functions (NEGF) method, respectively. We find in the incoherent regime near and above the threshold current a qualitative and quantitative agreement of both methods. Therefore, we show that THz-QCLs can be successfully optimized utilizing the numerically efficient EMC method.

Green's function calculation of the satellite spectrum of neon

International Nuclear Information System (INIS)

Kheifets, A.S.

1995-01-01

The single-hole Green's function with the lowest-order self-energy part has been used to calculate energies and spectroscopic factors of the neon ion ground and excited states which originated from the removal of the 2s and 2p valence electrons. The simplest two-hole-one-electron ion sates were included explicitly to the self-energy. More complex (m+l)-hole-m-electron states were treated implicitly by using the experimental energy of the two holes in the simplest ion states. The results of the calculation are found to be consistent with experimental satellite line positions and intensities obtained from recent photoionization and electron impact ionization measurements. 20 refs., 5 tabs

Green's functions in quantum chemistry - I. The Σ perturbation method

International Nuclear Information System (INIS)

Sebastian, K.L.

1978-01-01

As an improvement over the Hartree-Fock approximation, a Green's Function method - the Σ perturbation method - is investigated for molecular calculations. The method is applied to the hydrogen molecule and to the π-electron system of ethylene under PPP approximation. It is found that when the algebraic approximation is used, the energy obtained is better than that of the HF approach, but is not as good as that of the configuration-interaction method. The main advantage of this procedure is that it is devoid of the most serious defect of HF method, viz. incorrect dissociation limits. (K.B.)

A calculation method for finite depth free-surface green function

Directory of Open Access Journals (Sweden)

Yingyi Liu

2015-03-01

Full Text Available An improved boundary element method is presented for numerical analysis of hydrodynamic behavior of marine structures. A new algorithm for numerical solution of the finite depth free-surface Green function in three dimensions is developed based on multiple series representations. The whole range of the key parameter R/h is divided into four regions, within which different representation is used to achieve fast convergence. The well-known epsilon algorithm is also adopted to accelerate the convergence. The critical convergence criteria for each representation are investigated and provided. The proposed method is validated by several well-documented benchmark problems.

Tsunami excitation by inland/coastal earthquakes: the Green function approach

Directory of Open Access Journals (Sweden)

T. B. Yanovskaya

2003-01-01

Full Text Available In the framework of the linear theory, the representation theorem is derived for an incompressible liquid layer with a boundary of arbitrary shape and in a homogeneous gravity field. In addition, the asymptotic representation for the Green function, in a layer of constant thickness is obtained. The validity of the approach for the calculation of the tsunami wavefield based on the Green function technique is verified comparing the results with those obtained from the modal theory, for a liquid layer of infinite horizontal dimensions. The Green function approach is preferable for the estimation of the excitation spectra, since in the case of an infinite liquid layer it leads to simple analytical expressions. From this analysis it is easy to describe the peculiarities of tsunami excitation by different sources. The method is extended to the excitation of tsunami in a semiinfinite layer with a sloping boundary. Numerical modelling of the tsunami wavefield, excited by point sources at different distances from the coastline, shows that when the source is located at a distance from the coastline equal or larger than the source depth, the shore presence does not affect the excitation of the tsunami. When the source is moved towards thecoastline, the low frequency content in the excitation spectrum ecreases, while the high frequencies content increases dramatically. The maximum of the excitation spectra from inland sources, located at a distance from the shore like the source depth, becomes less than 10% of that radiated if the same source is located in the open ocean. The effect of the finiteness of the source is also studied and the excitation spectrum is obtained by integration over the fault area. Numerical modelling of the excitation spectra for different source models shows that, for a given seismic moment, the spectral level, as well as the maximum value of the spectra, decreases with increasing fault size. When the sources are located in the

Extracting the Green's function from the correlation of coda waves: A derivation based on stationary phase

International Nuclear Information System (INIS)

Snieder, Roel

2004-01-01

The Green's function of waves that propagate between two receivers can be found by cross-correlating multiply scattered waves recorded at these receivers. This technique obviates the need for a source at one of these locations, and is therefore called ''passive imaging.'' This principle has been explained by assuming that the normal modes of the system are uncorrelated and that all carry the same amount of energy (equipartitioning). Here I present an alternative derivation of passive imaging of the ballistic wave that is not based on normal modes. The derivation is valid for scalar waves in three dimensions, and for elastic surface waves. Passive imaging of the ballistic wave is based on the destructive interference of waves radiated from scatterers away from the receiver line, and the constructive interference of waves radiated from secondary sources near the receiver line. The derivation presented here shows that the global requirement of the equipartitioning of normal modes can be relaxed to the local requirement that the scattered waves propagate on average isotropically near the receivers

Discussion on interior greening decoration of residence

Science.gov (United States)

Tong, ZhiNeng

2018-02-01

Green plants bring endless natural energy into the room. This paper introduces the functions, principles and functions of indoor greening decoration from different angles. Its conclusion is that it has become an important measure to improve the living environment of the people, and through the interior greening decoration to create a harmonious living space of architecture, human and nature.

Extended two-particle Green close-quote s functions and optical potentials for two particle scattering by by many-body targets

International Nuclear Information System (INIS)

Brand, J.; Cederbaum, L.S.

1996-01-01

An extension of the fermionic particle-particle propagator is presented that possesses similar algebraic properties to the single-particle Green close-quote s function. In particular, this extended two-particle Green close-quote s function satisfies Dyson close-quote s equation and its self energy has the same analytic structure as the self energy of the single-particle Green close-quote s function. For the case of a system interacting with one-particle potentials only, the two-particle self energy takes on a particularly simple form, just like the common self energy does. The new two-particle self energy also serves as a well behaved optical potential for the elastic scattering of a two-particle projectile by a many-body target. Due to its analytic structure, the two-particle self energy avoids divergences that appear with effective potentials derived by other means. Copyright copyright 1996 Academic Press, Inc

One-particle many-body Green's function theory: Algebraic recursive definitions, linked-diagram theorem, irreducible-diagram theorem, and general-order algorithms.

Science.gov (United States)

Hirata, So; Doran, Alexander E; Knowles, Peter J; Ortiz, J V

2017-07-28

A thorough analytical and numerical characterization of the whole perturbation series of one-particle many-body Green's function (MBGF) theory is presented in a pedagogical manner. Three distinct but equivalent algebraic (first-quantized) recursive definitions of the perturbation series of the Green's function are derived, which can be combined with the well-known recursion for the self-energy. Six general-order algorithms of MBGF are developed, each implementing one of the three recursions, the ΔMPn method (where n is the perturbation order) [S. Hirata et al., J. Chem. Theory Comput. 11, 1595 (2015)], the automatic generation and interpretation of diagrams, or the numerical differentiation of the exact Green's function with a perturbation-scaled Hamiltonian. They all display the identical, nondivergent perturbation series except ΔMPn, which agrees with MBGF in the diagonal and frequency-independent approximations at 1≤n≤3 but converges at the full-configuration-interaction (FCI) limit at n=∞ (unless it diverges). Numerical data of the perturbation series are presented for Koopmans and non-Koopmans states to quantify the rate of convergence towards the FCI limit and the impact of the diagonal, frequency-independent, or ΔMPn approximation. The diagrammatic linkedness and thus size-consistency of the one-particle Green's function and self-energy are demonstrated at any perturbation order on the basis of the algebraic recursions in an entirely time-independent (frequency-domain) framework. The trimming of external lines in a one-particle Green's function to expose a self-energy diagram and the removal of reducible diagrams are also justified mathematically using the factorization theorem of Frantz and Mills. Equivalence of ΔMPn and MBGF in the diagonal and frequency-independent approximations at 1≤n≤3 is algebraically proven, also ascribing the differences at n = 4 to the so-called semi-reducible and linked-disconnected diagrams.

High-Order Analytic Expansion of Disturbing Function for Doubly Averaged Circular Restricted Three-Body Problem

Directory of Open Access Journals (Sweden)

Takashi Ito

2016-01-01

Full Text Available Terms in the analytic expansion of the doubly averaged disturbing function for the circular restricted three-body problem using the Legendre polynomial are explicitly calculated up to the fourteenth order of semimajor axis ratio (α between perturbed and perturbing bodies in the inner case (α1. The expansion outcome is compared with results from numerical quadrature on an equipotential surface. Comparison with direct numerical integration of equations of motion is also presented. Overall, the high-order analytic expansion of the doubly averaged disturbing function yields a result that agrees well with the numerical quadrature and with the numerical integration. Local extremums of the doubly averaged disturbing function are quantitatively reproduced by the high-order analytic expansion even when α is large. Although the analytic expansion is not applicable in some circumstances such as when orbits of perturbed and perturbing bodies cross or when strong mean motion resonance is at work, our expansion result will be useful for analytically understanding the long-term dynamical behavior of perturbed bodies in circular restricted three-body systems.

General atomistic approach for modeling metal-semiconductor interfaces using density functional theory and nonequilibrium Green's function

DEFF Research Database (Denmark)

Stradi, Daniele; Martinez, Umberto; Blom, Anders

2016-01-01

Metal-semiconductor contacts are a pillar of modern semiconductor technology. Historically, their microscopic understanding has been hampered by the inability of traditional analytical and numerical methods to fully capture the complex physics governing their operating principles. Here we introduce...... an atomistic approach based on density functional theory and nonequilibrium Green's function, which includes all the relevant ingredients required to model realistic metal-semiconductor interfaces and allows for a direct comparison between theory and experiments via I-Vbias curve simulations. We apply...... interfaces as it neglects electron tunneling, and that finite-size atomistic models have problems in describing these interfaces in the presence of doping due to a poor representation of space-charge effects. Conversely, the present method deals effectively with both issues, thus representing a valid...

Green-Tao theorem in function fields

OpenAIRE

Le, Thai Hoang

2009-01-01

We adapt the proof of the Green-Tao theorem on arithmetic progressions in primes to the setting of polynomials over a finite field, to show that for every $k$, the irreducible polynomials in $\\mathbf{F}_q[t]$ contain configurations of the form $\\{f+ Pg : \\d(P)

The infrared behaviour of QCD Green's functions. Confinement, dynamical symmetry breaking, and hadrons as relativistic bound states

Science.gov (United States)

Alkofer, Reinhard; von Smekal, Lorenz

2001-11-01

Recent studies of QCD Green's functions and their applications in hadronic physics are reviewed. We discuss the definition of the generating functional in gauge theories, in particular, the rôle of redundant degrees of freedom, possibilities of a complete gauge fixing versus gauge fixing in presence of Gribov copies, BRS invariance and positivity. The apparent contradiction between positivity and colour antiscreening in combination with BRS invariance in QCD is considered. Evidence for the violation of positivity by quarks and transverse gluons in the covariant gauge is collected, and it is argued that this is one manifestation of confinement. We summarise the derivation of the Dyson-Schwinger equations (DSEs) of QED and QCD. For the latter, the implications of BRS invariance on the Green's functions are explored. The possible influence of instantons on DSEs is discussed in a two-dimensional model. In QED in (2+1) and (3+1) dimensions, the solutions for Green's functions provide tests of truncation schemes which can under certain circumstances be extended to the DSEs of QCD. We discuss some limitations of such extensions and assess the validity of assumptions for QCD as motivated from studies in QED. Truncation schemes for DSEs are discussed in axial and related gauges, as well as in the Landau gauge. Furthermore, we review the available results from a systematic non-perturbative expansion scheme established for Landau gauge QCD. Comparisons to related lattice results, where available, are presented. The applications of QCD Green's functions to hadron physics are summarised. Properties of ground state mesons are discussed on the basis of the ladder Bethe-Salpeter equation for quarks and antiquarks. The Goldstone nature of pseudoscalar mesons and a mechanism for diquark confinement beyond the ladder approximation are reviewed. We discuss some properties of ground state baryons based on their description as Bethe-Salpeter/Faddeev bound states of quark

Green's function asymptotics near the internal edges of spectra of periodic elliptic operators. Spectral edge case

KAUST Repository

Kuchment, Peter

2012-06-21

Precise asymptotics known for the Green\\'s function of the Laplace operator have found their analogs for periodic elliptic operators of the second order at and below the bottom of the spectrum. Due to the band-gap structure of the spectra of such operators, the question arises whether similar results can be obtained near or at the edges of spectral gaps. As the result of this work shows, this is possible at a spectral edge when the dimension d ≥ 3. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electron transport in polycyclic aromatic hydrocarbons/boron nitride hybrid structures: density functional theory combined with the nonequilibrium Green's function.

Science.gov (United States)

Panahi, S F K S; Namiranian, Afshin; Soleimani, Maryam; Jamaati, Maryam

2018-02-07

We investigate the electronic transport properties of two types of junction based on single polyaromatic hydrocarbons (PAHs) and PAHs embedded in boron nitride (h-BN) nanoribbons, using nonequilibrium Green's functions (NEGF) and density functional theory (DFT). In the PAH junctions, a Fano resonance line shape at the Fermi energy in the transport feature can be clearly seen. In hybrid junctions, structural asymmetries enable interactions between the electronic states, leading to observation of interface-based transport. Our findings reveal that the interface of PAH/h-BN strongly affects the transport properties of the structures.

Combinations of laxatives and green banana biomass on the treatment of functional constipation in children and adolescents: a randomized study.

Science.gov (United States)

Cassettari, Vanessa Mello Granado; Machado, Nilton Carlos; Lourenção, Pedro Luiz Toledo de Arruda; Carvalho, Marry Assis; Ortolan, Erika Veruska Paiva

2018-01-05

Evaluate the effect of combinations of green banana biomass and laxatives in children and adolescents with chronic constipation. This was a randomized study of 80 children and adolescents with functional constipation according to the Rome IV Criteria, who were divided into five groups: (1) green banana biomass alone; (2) green banana biomass plus PEG 3350 with electrolytes; (3) green banana biomass plus sodium picosulfate; (4) PEG 3350 with electrolytes alone; and (5) sodium picosulfate alone. Primary outcome measure was the reduction of the proportion of patients with Bristol Stool Form Scale ratings 1 or 2. Secondary outcome measures were: increase of the proportion of >3 bowel movements/week and reduction of the proportion of fecal incontinence, straining on defecation, painful defecation, blood in stool, abdominal pain, and decreased laxative doses. On consumption of green banana biomass alone, a statistically significant reduction was observed in the proportion of children with Bristol Stool Form Scale rating 1 or 2, straining on defecation, painful defecation, and abdominal pain. Conversely, no reduction was observed in fecal incontinence episodes/week, blood in stool, and no increase was observed in the proportion of children with >3 bowel movements/week. The percentage of children who required decreased laxative dose was high when green banana biomass was associated with sodium picosulfate (87%), and PEG 3350 with electrolytes (63%). Green banana biomass alone and associated with laxatives was well tolerated, and no adverse effects were reported. Green banana biomass is advantageous as an adjunct therapy on functional constipation, mainly for reducing doses of laxatives. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Cancellation of spurious arrivals in Green's function extraction and the generalized optical theorem

Science.gov (United States)

Snieder, R.; Van Wijk, K.; Haney, M.; Calvert, R.

2008-01-01

The extraction of the Green's function by cross correlation of waves recorded at two receivers nowadays finds much application. We show that for an arbitrary small scatterer, the cross terms of scattered waves give an unphysical wave with an arrival time that is independent of the source position. This constitutes an apparent inconsistency because theory predicts that such spurious arrivals do not arise, after integration over a complete source aperture. This puzzling inconsistency can be resolved for an arbitrary scatterer by integrating the contribution of all sources in the stationary phase approximation to show that the stationary phase contributions to the source integral cancel the spurious arrival by virtue of the generalized optical theorem. This work constitutes an alternative derivation of this theorem. When the source aperture is incomplete, the spurious arrival is not canceled and could be misinterpreted to be part of the Green's function. We give an example of how spurious arrivals provide information about the medium complementary to that given by the direct and scattered waves; the spurious waves can thus potentially be used to better constrain the medium. ?? 2008 The American Physical Society.

Nucleon polarizabilities from deuteron Compton scattering within a Green's function hybrid approach

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, R.P.; Hemmert, T.R. [Technische Universitaet Muenchen, Institut fuer Theoretische Physik (T39), Physik-Department, Garching (Germany); Griesshammer, H.W. [Technische Universitaet Muenchen, Institut fuer Theoretische Physik (T39), Physik-Department, Garching (Germany); Universitaet Erlangen-Nuernberg, Institut fuer Theoretische Physik III, Naturwissenschaftliche Fakultaet I, Erlangen (Germany); The George Washington University, Center for Nuclear Studies, Department of Physics, Washington DC (United States)

2010-10-15

We examine elastic Compton scattering from the deuteron for photon energies ranging from zero to 100MeV, using state-of-the-art deuteron wave functions and NN potentials. Nucleon-nucleon rescattering between emission and absorption of the two photons is treated by Green's functions in order to ensure gauge invariance and the correct Thomson limit. With this Green's function hybrid approach, we fulfill the low-energy theorem of deuteron Compton scattering and there is no significant dependence on the deuteron wave function used. Concerning the nucleon structure, we use the chiral effective field theory with explicit {delta} (1232) degrees of freedom within the small-scale expansion up to leading-one-loop order. Agreement with available data is good at all energies. Our 2-parameter fit to all elastic {gamma} d data leads to values for the static isoscalar dipole polarizabilities which are in excellent agreement with the isoscalar Baldin sum rule. Taking this value as additional input, we find {alpha}{sub E}{sup s} = (11.3{+-}0.7(stat){+-}0.6(Baldin){+-}1(theory)){sup .}10{sup -4} fm{sup 3} and {beta}{sub M}{sup s} = (3.2{+-}0.7(stat){+-}0.6(Baldin){+-}1(theory)){sup .}10{sup -4} fm{sup 3} and conclude by comparison to the proton numbers that neutron and proton polarizabilities are the same within rather small errors. (orig.)

Significance of constraints associated with Green's functions in Hamiltonian perturbation theory

International Nuclear Information System (INIS)

Maharana, L.; Muller-Kirsten, H.J.W.; Wiedemann, A.

1987-01-01

In many formulations of Hamiltonian perturbation theory a Green's function becomes undefined when some parameter is allowed to vanish. Here various examples are discussed to illustrate this phenomenon, and it is shown that they are all realizations of a general theorem. The cases considered are examples in classical mechanics, quantum mechanics, electrodynamics and field theory. The prime object is to illustrate the unity of the examples and thus to make the application of the procedure to field theory models of current interest more transparent. One example that it is referred to is the skyrmion model

The behaviour of the Green function for the BFKL pomeron with running coupling

International Nuclear Information System (INIS)

Kowalski, H.; Lipatov, L.N.; Ross, D.A.

2015-08-01

We analyse here in LO the physical properties of the Green function solution for the BFKL equation. We show that the solution obeys the orthonormality conditions in the physical region and fulfills the completeness requirements. The unintegrated gluon density is shown to consists of a set of few poles with parameters which could be determined by comparison with the DIS data of high precision.

Replacing leads by self-energies using non-equilibrium Green's functions

International Nuclear Information System (INIS)

Michael, Fredrick; Johnson, M.D.

2003-01-01

Open quantum systems consist of semi-infinite leads which transport electrons to and from the device of interest. We show here that within the non-equilibrium Green's function technique for continuum systems, the leads can be replaced by simple c-number self-energies. Our starting point is an approach for continuum systems developed by Feuchtwang. The reformulation developed here is simpler to understand and carry out than the somewhat unwieldly manipulations typical in the Feuchtwang method. The self-energies turn out to have a limited variability: the retarded self-energy Σ r depends on the arbitrary choice of internal boundary conditions, but the non-equilibrium self-energy or scattering function Σ which determines transport is invariant for a broad class of boundary conditions. Expressed in terms of these self-energies, continuum non-equilibrium transport calculations take a particularly simple form similar to that developed for discrete systems

Recombination yield of geminate radical pairs in low magnetic fields - A Green's function method

International Nuclear Information System (INIS)

Doktorov, A.B.; Hansen, M.J.; Pedersen, J. Boiden

2006-01-01

An analytic expression for the recombination yield of a geminate radical pair with a single spin one half nuclei is derived. The expression is valid for any field strength of the static magnetic field. It is assumed that the spin mixing is caused solely by the hyperfine interaction of the nuclear spin and the difference in Zeeman energies of the two radical partners, that the recombination occurs at the distance of closest approach, and that there is a locally strong dephasing at contact. This is a special result of a new general approach where a Green's function technique is used to recast the stochastic Liouville equation into a low dimensional matrix equation that is particularly convenient for locally strong dephasing systems. The equation is expressed in terms of special values (determined by the magnetic parameters) of the Green's function for the relative motion of the radicals and it is therefore valid for any motional model, e.g. diffusion, one and two site models. The applicability of the strong dephasing approximation is illustrated by comparison with numerical exact results

Use of time space Green's functions in the computation of transient eddy current fields

International Nuclear Information System (INIS)

Davey, K.; Turner, L.

1988-01-01

The utility of integral equations to solve eddy current problems has been borne out by numerous computations in the past few years, principally in sinusoidal steady-state problems. This paper attempts to examine the applicability of the integral approaches in both time and space for the more generic transient problem. The basic formulation for the time space Green's function approach is laid out. A technique employing Gauss-Laguerre integration is employed to realize the temporal solution, while Gauss--Legendre integration is used to resolve the spatial field character. The technique is then applied to the fusion electromagnetic induction experiments (FELIX) cylinder experiments in both two and three dimensions. It is found that quite accurate solutions can be obtained using rather coarse time steps and very few unknowns; the three-dimensional field solution worked out in this context used basically only four unknowns. The solution appears to be somewhat sensitive to the choice of time step, a consequence of a numerical instability imbedded in the Green's function near the origin

β-cyclodextrin functionalized on glass micro-particles: A green catalyst for selective oxidation of toluene to benzaldehyde

Energy Technology Data Exchange (ETDEWEB)

Tahir, M. Nazir, E-mail: tahir.muhammad_nazir@courrier.uqam.ca [Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, DK-9220, Aalborg East (Denmark); Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8 (Canada); Nielsen, Thorbjørn T.; Larsen, Kim L. [Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, DK-9220, Aalborg East (Denmark)

2016-12-15

Highlights: • Functionalization of βCD onto glass micro-particles (GMP-βCD). • Application of GMP-βCD as a green catalyst for the oxidation of toluene. • 82% yield at room temperature. • Repeated use of the catalyst for several cycles. - Abstract: Oxidation of toluene is considered an important process which often requires high temperatures and specific conditions along with heavy-metals based catalysts. In this study, we have developed a green catalyst by functionalizing beta-cyclodextrin onto glass micro-particle surfaces. All surfaces were characterized by X-ray photoelectron spectroscopy and applied to catalyze the selective oxidation of toluene into benzaldehyde (82% yield) at room temperature. The catalyst was stable and could be used repeatedly for several cycles without losing efficiency.

Solution of the radiative transfer equation for Rayleigh scattering using the infinite medium Green's function

Science.gov (United States)

Biçer, M.; Kaşkaş, A.

2018-03-01

The infinite medium Green's function is used to solve the half-space albedo, slab albedo and Milne problems for the unpolarized Rayleigh scattering case; these problems are the most classical problems of radiative transfer theory. The numerical results are obtained and are compared with previous ones.

Neutron importance and the generalized Green function for the conventionally critical reactor with normalized neutron distribution

International Nuclear Information System (INIS)

Khromov, V.V.

1978-01-01

The notion of neutron importance when applied to nuclear reactor statics problems described by time-independent homogeneous equations of neutron transport with provision for normalization of neutron distribution is considered. An equation has been obtained for the function of neutron importance in a conditionally critical reactor with respect to an arbitrary nons linear functional determined for the normalized neutron distribution. Relation between this function and the generalized Green function of the selfconjugated operator of the reactor equation is determined and the formula of small perturbations for the functionals of a conditionally critical reactor is deduced

Root finding in the complex plane for seismo-acoustic propagation scenarios with Green's function solutions.

Science.gov (United States)

McCollom, Brittany A; Collis, Jon M

2014-09-01

A normal mode solution to the ocean acoustic problem of the Pekeris waveguide with an elastic bottom using a Green's function formulation for a compressional wave point source is considered. Analytic solutions to these types of waveguide propagation problems are strongly dependent on the eigenvalues of the problem; these eigenvalues represent horizontal wavenumbers, corresponding to propagating modes of energy. The eigenvalues arise as singularities in the inverse Hankel transform integral and are specified by roots to a characteristic equation. These roots manifest themselves as poles in the inverse transform integral and can be both subtle and difficult to determine. Following methods previously developed [S. Ivansson et al., J. Sound Vib. 161 (1993)], a root finding routine has been implemented using the argument principle. Using the roots to the characteristic equation in the Green's function formulation, full-field solutions are calculated for scenarios where an acoustic source lies in either the water column or elastic half space. Solutions are benchmarked against laboratory data and existing numerical solutions.

Spinor Green function in higher-dimensional cosmic string space-time in the presence of magnetic flux

International Nuclear Information System (INIS)

Spinelly, J.; Mello, E.R. Bezerra de

2008-01-01

In this paper we investigate the vacuum polarization effects associated with quantum fermionic charged fields in a generalized (d+1)-dimensional cosmic string space-times considering the presence of a magnetic flux along the string. In order to develop this analysis we calculate a general expression for the respective Green function, valid for several different values of d, which is expressed in terms of a bispinor associated with the square of the Dirac operator. Adopting this result, we explicitly calculate the renormalized vacuum expectation values of the energy-momentum tensors, (T A B ) Ren. , associated with massless fields. Moreover, for specific values of the parameters which codify the cosmic string and the fractional part of the ratio of the magnetic flux by the quantum one, we were able to present in closed forms the bispinor and the respective Green function for massive fields.

Representation of the three-body Coulomb Green's function in parabolic coordinates: paths of integration

International Nuclear Information System (INIS)

Zaytsev, S A

2010-01-01

The possibility of using straight-line paths of integration in computing the integral representation of the three-body Coulomb Green's function is discussed. In our numerical examples two different kinds of integration contours in the complex energy planes are considered. It is demonstrated that straight-line paths, which cross the positive real axis, are suitable for numerical computation.

Comparison of measurements of plasma clearance of Mebrofenine and of indocyanine green

International Nuclear Information System (INIS)

Maurel, G.; Coutris, G.; Vaubourdolle, M.; Attal, P.; Patureau, R.; Tabsoba, Th.; Mensch, B.; Askienazy, Pr.S.

1997-01-01

The importance of clearance measurements in evaluating renal or hepatic function needs not further demonstration. The isotopic methods were proved in renal exploration but their utilization in exploration of hepato-biliary function needs to be evaluated. In this work we have compared the measurement of plasma clearance by Mebrofenine, a radiopharmaceutical of specifically hepatic elimination, with the reference method, the clearance of indocyanine green. On the basis of scintigraphic data from 23 patients who benefited by a hepato-biliary exploration by Mebrofenine- 99m Tc for pre-surgery account and surveillance, we have determined the plasma clearance of this radiopharmaceutical. The method makes use of the curve of normalized cardiac activity by a blood sampling, taken 60 minutes after injection. The measurement of the clearance of indocyanine green was effected within a delay inferior to 1 month from the moment of biliary scintigraphy. The average clearance of Mebrofenine- 99m Tc is of 553 ml/min for 1.73 m 2 of corporal surface (typical interval is 374 ml/min), the value of indocyanine green is of 450 ml/min (typical interval is 229 ml/min). The two measurements of clearance are correlated (p = 0.05). In conclusion, the measurement of clearance by Mebrofenine- 99m appears to be adapted to the evaluation of hepato-biliary function

The difference between alternative averages

Directory of Open Access Journals (Sweden)

James Vaupel

2012-09-01

Full Text Available BACKGROUND Demographers have long been interested in how compositional change, e.g., change in age structure, affects population averages. OBJECTIVE We want to deepen understanding of how compositional change affects population averages. RESULTS The difference between two averages of a variable, calculated using alternative weighting functions, equals the covariance between the variable and the ratio of the weighting functions, divided by the average of the ratio. We compare weighted and unweighted averages and also provide examples of use of the relationship in analyses of fertility and mortality. COMMENTS Other uses of covariances in formal demography are worth exploring.

Green's function of compressible Petschek-type magnetic reconnection

International Nuclear Information System (INIS)

Penz, Thomas; Semenov, V.S.; Ivanova, V.V.; Heyn, M.F.; Ivanov, I.B.; Biernat, H.K.

2006-01-01

We present a method to analyze the wave and shock structures arising from Petschek-type magnetic reconnection. Based on a time-dependent analytical approach developed by Heyn and Semenov [Phys. Plasmas 3, 2725 (1996)] and Semenov et al. [Phys. Plasmas 11, 62 (2004)], we calculate the perturbations caused by a delta function-shaped reconnection electric field, which allows us to achieve a representation of the plasma variables in the form of Green's functions. Different configurations for the initial conditions are considered. In the case of symmetric, antiparallel magnetic fields and symmetric plasma density, the well-known structure of an Alfven discontinuity, a fast body wave, a slow shock, a slow wave, and a tube wave occurs. In the case of asymmetric, antiparallel magnetic fields, additionally surface waves are found. We also discuss the case of symmetric, antiparallel magnetic fields and asymmetric densities, which leads to a faster propagation in the lower half plane, causing side waves forming a Mach cone in the upper half plane. Complex effects like anisotropic propagation characteristics, intrinsic wave coupling, and the generation of different nonlinear and linear wave modes in a finite β plasma are retained. The temporal evolution of these wave and shock structures is shown

Green partial packet recovery in wireless sensor networks

KAUST Repository

Daghistani, Anas

2015-08-18

Partial packet recovery is well known for increasing network throughput and reducing frame retransmissions. However, partial packet recovery methods in the literature are not energy-aware and hence they are not suitable for the battery powered wireless sensor motes. We propose Green-Frag, a novel adaptive partial packet recovery mechanism that is energy friendly. It can help prolonging the battery life of wireless sensor motes that are usually resource constrained. It dynamically partitions the frame into smaller blocks to avoid dropping the whole frame due to a single bit error. Also, Green-Frag is able to tolerate high interference and save energy by varying the transmit power based on channel quality and interference pattern. We experimentally evaluate the energy efficiency as well as goodput and delay of Green-Frag using our TelosB sensor mote testbed. We find that Green-Frag reduces energy consumption by 33% on average compared to the state of the art partial packet recovery scheme in the literature in the presence of Wi-Fi interference. In the worst case, this reduction in energy consumption comes at the cost of 10% reduction in goodput. Finally, Green-Frag reduces the latency by 22% on average compared to other static frame fragmentation schemes.

Thermal transport in isotopically disordered carbon nanotubes: a comparison between Green's functions and Boltzmann approaches

International Nuclear Information System (INIS)

Stoltz, G; Lazzeri, M; Mauri, F

2009-01-01

We present a study of the phononic thermal conductivity of isotopically disordered carbon nanotubes. In particular, the behaviour of the thermal conductivity as a function of the system length is investigated, using Green's function techniques to compute the transmission across the system. The method is implemented using linear scaling algorithms, which allow us to reach systems of lengths up to L = 2.5 μm (with up to 200 000 atoms). As for 1D systems, it is observed that the conductivity diverges with the system size L. We also observe a dramatic decrease of the thermal conductance for systems of experimental sizes (roughly 80% at room temperature for L = 2.5 μm), when a large fraction of isotopic disorder is introduced. The results obtained with Green's function techniques are compared to results obtained with a Boltzmann description of thermal transport. There is a good agreement between both approaches for systems of experimental sizes, even in the presence of Anderson localization. This is particularly interesting since the computation of the transmission using Boltzmann's equation is much less computationally expensive, so that larger systems may be studied with this method.

Cost-Benefit Analysis of Green Infrastructures on Community Stormwater Reduction and Utilization: A Case of Beijing, China.

Science.gov (United States)

Liu, Wen; Chen, Weiping; Feng, Qi; Peng, Chi; Kang, Peng

2016-12-01

Cost-benefit analysis is demanded for guiding the plan, design and construction of green infrastructure practices in rapidly urbanized regions. We developed a framework to calculate the costs and benefits of different green infrastructures on stormwater reduction and utilization. A typical community of 54,783 m 2 in Beijing was selected for case study. For the four designed green infrastructure scenarios (green space depression, porous brick pavement, storage pond, and their combination), the average annual costs of green infrastructure facilities are ranged from 40.54 to 110.31 thousand yuan, and the average of the cost per m 3 stormwater reduction and utilization is 4.61 yuan. The total average annual benefits of stormwater reduction and utilization by green infrastructures of the community are ranged from 63.24 to 250.15 thousand yuan, and the benefit per m 3 stormwater reduction and utilization is ranged from 5.78 to 11.14 yuan. The average ratio of average annual benefit to cost of four green infrastructure facilities is 1.91. The integrated facilities had the highest economic feasibility with a benefit to cost ratio of 2.27, and followed by the storage pond construction with a benefit to cost ratio of 2.14. The results suggested that while the stormwater reduction and utilization by green infrastructures had higher construction and maintenance costs, their comprehensive benefits including source water replacements benefits, environmental benefits and avoided cost benefits are potentially interesting. The green infrastructure practices should be promoted for sustainable management of urban stormwater.

Green's Theorem for Sign Data

OpenAIRE

Houston, Louis M.

2012-01-01

Sign data are the signs of signal added to noise. It is well known that a constant signal can be recovered from sign data. In this paper, we show that an integral over variant signal can be recovered from an integral over sign data based on the variant signal. We refer to this as a generalized sign data average. We use this result to derive a Green's theorem for sign data. Green's theorem is important to various seismic processing methods, including seismic migration. Results in this paper ge...

Green Transformational Leadership and Green Performance: The Mediation Effects of Green Mindfulness and Green Self-Efficacy

Directory of Open Access Journals (Sweden)

Yu-Shan Chen

2014-09-01

Full Text Available No prior literature explores the influence of green transformational leadership on green performance, thus, this study develops a novel research framework to fill the research gap. This study investigates the influence of green transformational leadership on green performance and discusses the mediation effects of green mindfulness and green self-efficacy by means of structural equation modeling (SEM. The results indicate that green transformational leadership positively influences green mindfulness, green self-efficacy, and green performance. Moreover, this study demonstrates that the positive relationship between green transformational leadership and green performance is partially mediated by the two mediators: green mindfulness and green self-efficacy. It means that green transformational leadership can not only directly affect green performance positively but also indirectly affect it positively through green mindfulness and green self-efficacy. Therefore, firms need to raise their green transformational leadership, green mindfulness, and green self-efficacy to increase their green performance.

Infrared asymptotics and Dyson-Schwinger equations for the gauge-invariant spinor Green function in quantum electrodynamics

International Nuclear Information System (INIS)

Skachkov, N.B.; Solovtsov, I.L.; Shevchenko, O.Yu.

1985-01-01

The Dayson-Schwinger equations for the gauge-invariant (G.I.) spinor Green function are derived for an Abelian case. On the basis of these equations as well as the functional integration method the behaviour of the G.I. spinor propagator is studied in the infrared region. It is shown that the G.I. propagator has a singularity of a simple pole in this region

Electronic diffraction tomography by Green's functions and singular values decompositions

International Nuclear Information System (INIS)

Mayer, A.

2001-01-01

An inverse scattering technique is developed to enable a three-dimensional sample reconstruction from the diffraction figures obtained for different sample orientations by electronic projection microscopy, thus performing a diffraction tomography. In its Green's-functions formulation, this technique takes account of all orders of diffraction by performing an iterative reconstruction of the wave function on the observation screen and in the sample. In a final step, these quantities enable a reconstruction of the potential-energy distribution, which is assumed real valued. The method relies on the use of singular values decomposition techniques, thus providing the best least-squares solutions and enabling a reduction of noise. The technique is applied to the analysis of a three-dimensional nanometric sample that is observed in Fresnel conditions with an electron energy of 40 eV. The algorithm turns out to provide results with a mean relative error around 3% and to be stable against random noise

Low-rank canonical-tensor decomposition of potential energy surfaces: application to grid-based diagrammatic vibrational Green's function theory

Science.gov (United States)

Rai, Prashant; Sargsyan, Khachik; Najm, Habib; Hermes, Matthew R.; Hirata, So

2017-09-01

A new method is proposed for a fast evaluation of high-dimensional integrals of potential energy surfaces (PES) that arise in many areas of quantum dynamics. It decomposes a PES into a canonical low-rank tensor format, reducing its integral into a relatively short sum of products of low-dimensional integrals. The decomposition is achieved by the alternating least squares (ALS) algorithm, requiring only a small number of single-point energy evaluations. Therefore, it eradicates a force-constant evaluation as the hotspot of many quantum dynamics simulations and also possibly lifts the curse of dimensionality. This general method is applied to the anharmonic vibrational zero-point and transition energy calculations of molecules using the second-order diagrammatic vibrational many-body Green's function (XVH2) theory with a harmonic-approximation reference. In this application, high dimensional PES and Green's functions are both subjected to a low-rank decomposition. Evaluating the molecular integrals over a low-rank PES and Green's functions as sums of low-dimensional integrals using the Gauss-Hermite quadrature, this canonical-tensor-decomposition-based XVH2 (CT-XVH2) achieves an accuracy of 0.1 cm-1 or higher and nearly an order of magnitude speedup as compared with the original algorithm using force constants for water and formaldehyde.

Green function of the double-fractional Fokker-Planck equation: Path integral and stochastic differential equations

Science.gov (United States)

Kleinert, H.; Zatloukal, V.

2013-11-01

The statistics of rare events, the so-called black-swan events, is governed by non-Gaussian distributions with heavy power-like tails. We calculate the Green functions of the associated Fokker-Planck equations and solve the related stochastic differential equations. We also discuss the subject in the framework of path integration.

Functionalized dicationic ionic liquids: Green and efficient ...

Indian Academy of Sciences (India)

have the advantages of liquid and solid phase together.11. Task-specific ionic liquids ... more attention as alternative reaction media in green chemistry than conventional ..... The reaction mixture was divided into two. Figure 3. Reusability of ...

Quasiaverages, symmetry breaking and irreducible Green functions method

Directory of Open Access Journals (Sweden)

A.L.Kuzemsky

2010-01-01

Full Text Available The development and applications of the method of quasiaverages to quantum statistical physics and to quantum solid state theory and, in particular, to quantum theory of magnetism, were considered. It was shown that the role of symmetry (and the breaking of symmetries in combination with the degeneracy of the system was reanalyzed and essentially clarified within the framework of the method of quasiaverages. The problem of finding the ferromagnetic, antiferromagnetic and superconducting "symmetry broken" solutions of the correlated lattice fermion models was discussed within the irreducible Green functions method. A unified scheme for the construction of generalized mean fields (elastic scattering corrections and self-energy (inelastic scattering in terms of the equations of motion and Dyson equation was generalized in order to include the "source fields". This approach complements previous studies of microscopic theory of antiferromagnetism and clarifies the concepts of Neel sublattices for localized and itinerant antiferromagnetism and "spin-aligning fields" of correlated lattice fermions.

Dyadic Green's function of a cluster of spheres.

Science.gov (United States)

Moneda, Angela P; Chrissoulidis, Dimitrios P

2007-11-01

The electric dyadic Green's function (dGf) of a cluster of spheres is obtained by application of the superposition principle, dyadic algebra, and the indirect mode-matching method. The analysis results in a set of linear equations for the unknown, vector, wave amplitudes of the dGf; that set is solved by truncation and matrix inversion. The theory is exact in the sense that no simplifying assumptions are made in the analytical steps leading to the dGf, and it is general in the sense that any number, position, size and electrical properties can be considered for the spheres that cluster together. The point source can be anywhere, even within one of the spheres. Energy conservation, reciprocity, and other tests prove that this solution is correct. Numerical results are presented for an electric Hertz dipole radiating in the presence of an array of rexolite spheres, which manifests lensing and beam-forming capabilities.

Dyadic Green's function of an eccentrically stratified sphere.

Science.gov (United States)

Moneda, Angela P; Chrissoulidis, Dimitrios P

2014-03-01

The electric dyadic Green's function (dGf) of an eccentrically stratified sphere is built by use of the superposition principle, dyadic algebra, and the addition theorem of vector spherical harmonics. The end result of the analytical formulation is a set of linear equations for the unknown vector wave amplitudes of the dGf. The unknowns are calculated by truncation of the infinite sums and matrix inversion. The theory is exact, as no simplifying assumptions are required in any one of the analytical steps leading to the dGf, and it is general in the sense that any number, position, size, and electrical properties can be considered for the layers of the sphere. The point source can be placed outside of or in any lossless part of the sphere. Energy conservation, reciprocity, and other checks verify that the dGf is correct. A numerical application is made to a stratified sphere made of gold and glass, which operates as a lens.

A Green function approach to superconductivity in nanofilms

Energy Technology Data Exchange (ETDEWEB)

Saniz, Rolando; Partoens, Bart; Peeters, Francois [Universiteit Antwerpen, Antwerpen (Belgium)

2012-07-01

We reformulate the BCS theory of superconductivity in the Green function framework in such a way that it is readily applied to inhomogeneous systems. We study here nanofilms and go beyond previous models in that we take into account the effects of confinement on electron-phonon coupling, as well as on the electron and phonon fields. We show that, contrary to what has been advanced in recent years, the increases of the density of states as the film thickness increases will tend to suppress the critical temperature, and not enhance it. Instead, it is the increase of the phonon modes with increasing film thickness that can lead to increases of the critical temperature above the bulk value. Further, we show that the multigap character of superconductivity in nanofilms will result in general in a condensate composed of subcondensates with different coherence lengths. This is in analogy with the very recent suggestion that different coherence lengths exist in two-gap superconductors such as MgB{sub 2}.

Ambient Noise Green's Function Simulation of Long-Period Ground Motions for Reverse Faulting

Science.gov (United States)

Miyake, H.; Beroza, G. C.

2009-12-01

Long-time correlation of ambient seismic noise has been demonstrated as a useful tool for strong ground motion prediction [Prieto and Beroza, 2008]. An important advantage of ambient noise Green's functions is that they can be used for ground motion simulation without resorting to either complex 3-D velocity structure to develop theoretical Green’s functions, or aftershock records for empirical Green’s function analysis. The station-to-station approach inherent to ambient noise Green’s functions imposes some limits to its application, since they are band-limited, applied at the surface, and for a single force. We explore the applicability of this method to strong motion prediction using the 2007 Chuetsu-oki, Japan, earthquake (Mw 6.6, depth = 9 km), which excited long-period ground motions in and around the Kanto basin almost 200 km from the epicenter. We test the performance of ambient noise Green's function for long-period ground motion simulation. We use three components of F-net broadband data at KZK station, which is located near the source region, as a virtual source, and three components of six F-net stations in and around the Kanto basin to calculate the response. An advantage to applying this approach in Japan is that ambient-noise sources are active in diverse directions. The dominant period of the ambient noise for the F-net datasets is mostly 7 s over the year, and amplitudes are largest in winter. This period matches the dominant periods of the Kanto and Niigata basins. For the 9 components of the ambient noise Green’s functions, we have confirmed long-period components corresponding to Love wave and Rayleigh waves that can be used for simulation of the 2007 Chuetsu-oki earthquake. The relative amplitudes, phases, and durations of the ambient noise Green’s functions at the F-net stations in and around the Kanto basin respect to F-net KZK station are fairly well matched with those of the observed ground motions for the 2007 Chuetsu

Analysis of the phonon surface specific heat using Green function techniques

International Nuclear Information System (INIS)

Silva Carrico, A. da; Albuquerque, E.L. de

1981-01-01

Green functions are derived for the displacement associated with acoustic vibrations in isotropic elastic media and used to evaluate the surface specific heat in the harmonic approximation. Only the low-temperature limit case is considered since, provided K sub(B) T/h is very small, the dispersion relation for the three acoustic branches can be replaced by its long-wavelenght form. The contributions of surface elastic waves of the Rayleigh and Love types are pointed out and their features discussed. The nature of the result and their relations to previous work in this field is also presented and discussed. (Author) [pt

Analysis of the phonon surface specific heat using Green function techniques

International Nuclear Information System (INIS)

Carrico, A.S.; Albuquerque, E.L.

1980-01-01

Green functions are derived for the displacement associated with acoustic vibrations in isotropic elastic media and used to evaluate the surface specific heat in the harmonic approximation. We consider only the low-temperature limit case since, provided K B 1/h is very samll, we can replace the dispersion relation for the three acoustic branches by its long-wavelenghts form. The contributions of surface elastic waves ot the Rayleigh and Love types are pointed out and their features discussed. The nature of the result and their relations to previous work in this field is also presented and discussed. (author) [pt

Biophysical Approach to Mechanisms of Cancer Prevention and Treatment with Green Tea Catechins.

Science.gov (United States)

Suganuma, Masami; Takahashi, Atsushi; Watanabe, Tatsuro; Iida, Keisuke; Matsuzaki, Takahisa; Yoshikawa, Hiroshi Y; Fujiki, Hirota

2016-11-18

Green tea catechin and green tea extract are now recognized as non-toxic cancer preventives for humans. We first review our brief historical development of green tea cancer prevention. Based on exciting evidence that green tea catechin, (-)-epigallocatechin gallate (EGCG) in drinking water inhibited lung metastasis of B16 melanoma cells, we and other researchers have studied the inhibitory mechanisms of metastasis with green tea catechins using biomechanical tools, atomic force microscopy (AFM) and microfluidic optical stretcher. Specifically, determination of biophysical properties of cancer cells, low cell stiffness, and high deformability in relation to migration, along with biophysical effects, were studied by treatment with green tea catechins. The study with AFM revealed that low average values of Young's moduli, indicating low cell stiffness, are closely associated with strong potential of cell migration and metastasis for various cancer cells. It is important to note that treatments with EGCG and green tea extract elevated the average values of Young's moduli resulting in increased stiffness (large elasticity) of melanomas and various cancer cells. We discuss here the biophysical basis of multifunctions of green tea catechins and green tea extract leading to beneficial effects for cancer prevention and treatment.

Green materials for sustainable development

Science.gov (United States)

Purwasasmita, B. S.

2017-03-01

Sustainable development is an integrity of multidiscipline concept combining ecological, social and economic aspects to construct a liveable human living system. The sustainable development can be support through the development of green materials. Green materials offers a unique characteristic and properties including abundant in nature, less toxic, economically affordable and versatility in term of physical and chemical properties. Green materials can be applied for a numerous field in science and technology applications including for energy, building, construction and infrastructures, materials science and engineering applications and pollution management and technology. For instance, green materials can be developed as a source for energy production. Green materials including biomass-based source can be developed as a source for biodiesel and bioethanol production. Biomass-based materials also can be transformed into advanced functionalized materials for advanced bio-applications such as the transformation of chitin into chitosan which further used for biomedicine, biomaterials and tissue engineering applications. Recently, cellulose-based material and lignocellulose-based materials as a source for the developing functional materials attracted the potential prospect for biomaterials, reinforcing materials and nanotechnology. Furthermore, the development of pigment materials has gaining interest by using the green materials as a source due to their unique properties. Eventually, Indonesia as a large country with a large biodiversity can enhance the development of green material to strengthen our nation competitiveness and develop the materials technology for the future.

Green Synthesis, Characterization and Application of Proanthocyanidins-Functionalized Gold Nanoparticles

Directory of Open Access Journals (Sweden)

Linhai Biao

2018-01-01

Full Text Available Green synthesis of gold nanoparticles using plant extracts is one of the more promising approaches for obtaining environmentally friendly nanomaterials for biological applications and environmental remediation. In this study, proanthocyanidins-functionalized gold nanoparticles were synthesized via a hydrothermal method. The obtained gold nanoparticles were characterized by ultraviolet and visible spectrophotometry (UV-Vis, Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM and X-ray diffraction (XRD measurements. UV-Vis and FTIR results indicated that the obtained products were mainly spherical in shape, and that the phenolic hydroxyl of proanthocyanidins had strong interactions with the gold surface. TEM and XRD determination revealed that the synthesized gold nanoparticles had a highly crystalline structure and good monodispersity. The application of proanthocyanidins-functionalized gold nanoparticles for the removal of dyes and heavy metal ions Ni2+, Cu2+, Cd2+ and Pb2+ in an aqueous solution was investigated. The primary results indicate that proanthocyanidins-functionalized gold nanoparticles had high removal rates for the heavy metal ions and dye, which implies that they have potential applications as a new kind of adsorbent for the removal of contaminants in aqueous solution.

Green's function enriched Poisson solver for electrostatics in many-particle systems

Science.gov (United States)

Sutmann, Godehard

2016-06-01

A highly accurate method is presented for the construction of the charge density for the solution of the Poisson equation in particle simulations. The method is based on an operator adjusted source term which can be shown to produce exact results up to numerical precision in the case of a large support of the charge distribution, therefore compensating the discretization error of finite difference schemes. This is achieved by balancing an exact representation of the known Green's function of regularized electrostatic problem with a discretized representation of the Laplace operator. It is shown that the exact calculation of the potential is possible independent of the order of the finite difference scheme but the computational efficiency for higher order methods is found to be superior due to a faster convergence to the exact result as a function of the charge support.

Data-driven Green's function retrieval and application to imaging with multidimensional deconvolution

Science.gov (United States)

Broggini, Filippo; Wapenaar, Kees; van der Neut, Joost; Snieder, Roel

2014-01-01

An iterative method is presented that allows one to retrieve the Green's function originating from a virtual source located inside a medium using reflection data measured only at the acquisition surface. In addition to the reflection response, an estimate of the travel times corresponding to the direct arrivals is required. However, no detailed information about the heterogeneities in the medium is needed. The iterative scheme generalizes the Marchenko equation for inverse scattering to the seismic reflection problem. To give insight in the mechanism of the iterative method, its steps for a simple layered medium are analyzed using physical arguments based on the stationary phase method. The retrieved Green's wavefield is shown to correctly contain the multiples due to the inhomogeneities present in the medium. Additionally, a variant of the iterative scheme enables decomposition of the retrieved wavefield into its downgoing and upgoing components. These wavefields then enable creation of a ghost-free image of the medium with either cross correlation or multidimensional deconvolution, presenting an advantage over standard prestack migration.

No-neighbours recurrence schemes for space-time Green's functions on a 3D simple cubic lattice

NARCIS (Netherlands)

De Hon, Bastiaan P.; Floris, Sander J.; Arnold, John M.

2018-01-01

Application of multivariate creative telescoping to a finite triple sum representation of the discrete space-time Green's function for an arbitrary numeric (non-symbolic) lattice point on a 3D simple cubic lattice produces a fast, no-neighbours, seventh-order, eighteenth-degree, discrete-time

Compact Representation for Specific Heat of Interacting Fermion Systems in Terms of Fully Renormalized Matsubara Green Function

OpenAIRE

Miyake, Kazumasa; Tsuruta, Atsushi

2015-01-01

On the basis of the Luttinger-Ward formalism for the thermodynamic potential, the specific heat of single-component interacting fermion systems with fixed chemical potential is compactly expressed in terms of the fully renormalized Matsubara Green function.

Post Construction Green Infrastructure Performance Monitoring Parameters and Their Functional Components

Directory of Open Access Journals (Sweden)

Thewodros K. Geberemariam

2016-12-01

Full Text Available Drainage system infrastructures in most urbanized cities have reached or exceeded their design life cycle and are characterized by running with inadequate capacity. These highly degraded infrastructures are already overwhelmed and continued to impose a significant challenge to the quality of water and ecological systems. With predicted urban growth and climate change the situation is only going to get worse. As a result, municipalities are increasingly considering the concept of retrofitting existing stormwater drainage systems with green infrastructure practices as the first and an important step to reduce stormwater runoff volume and pollutant load inputs into combined sewer systems (CSO and wastewater facilities. Green infrastructure practices include an open green space that can absorb stormwater runoff, ranging from small-scale naturally existing pocket of lands, right-of-way bioswales, and trees planted along the sidewalk as well as large-scale public parks. Despite the growing municipalities’ interest to retrofit existing stormwater drainage systems with green infrastructure, few studies and relevant information are available on their performance and cost-effectiveness. Therefore, this paper aims to help professionals learn about and become familiar with green infrastructure, decrease implementation barriers, and provide guidance for monitoring green infrastructure using the combination of survey questionnaires, meta-narrative and systematic literature review techniques.

On the multiple zeros of a real analytic function with applications to the averaging theory of differential equations

Science.gov (United States)

García, Isaac A.; Llibre, Jaume; Maza, Susanna

2018-06-01

In this work we consider real analytic functions , where , Ω is a bounded open subset of , is an interval containing the origin, are parameters, and ε is a small parameter. We study the branching of the zero-set of at multiple points when the parameter ε varies. We apply the obtained results to improve the classical averaging theory for computing T-periodic solutions of λ-families of analytic T-periodic ordinary differential equations defined on , using the displacement functions defined by these equations. We call the coefficients in the Taylor expansion of in powers of ε the averaged functions. The main contribution consists in analyzing the role that have the multiple zeros of the first non-zero averaged function. The outcome is that these multiple zeros can be of two different classes depending on whether the zeros belong or not to the analytic set defined by the real variety associated to the ideal generated by the averaged functions in the Noetheriang ring of all the real analytic functions at . We bound the maximum number of branches of isolated zeros that can bifurcate from each multiple zero z 0. Sometimes these bounds depend on the cardinalities of minimal bases of the former ideal. Several examples illustrate our results and they are compared with the classical theory, branching theory and also under the light of singularity theory of smooth maps. The examples range from polynomial vector fields to Abel differential equations and perturbed linear centers.

Biophysical Approach to Mechanisms of Cancer Prevention and Treatment with Green Tea Catechins

Directory of Open Access Journals (Sweden)

Masami Suganuma

2016-11-01

Full Text Available Green tea catechin and green tea extract are now recognized as non-toxic cancer preventives for humans. We first review our brief historical development of green tea cancer prevention. Based on exciting evidence that green tea catechin, (−-epigallocatechin gallate (EGCG in drinking water inhibited lung metastasis of B16 melanoma cells, we and other researchers have studied the inhibitory mechanisms of metastasis with green tea catechins using biomechanical tools, atomic force microscopy (AFM and microfluidic optical stretcher. Specifically, determination of biophysical properties of cancer cells, low cell stiffness, and high deformability in relation to migration, along with biophysical effects, were studied by treatment with green tea catechins. The study with AFM revealed that low average values of Young’s moduli, indicating low cell stiffness, are closely associated with strong potential of cell migration and metastasis for various cancer cells. It is important to note that treatments with EGCG and green tea extract elevated the average values of Young’s moduli resulting in increased stiffness (large elasticity of melanomas and various cancer cells. We discuss here the biophysical basis of multifunctions of green tea catechins and green tea extract leading to beneficial effects for cancer prevention and treatment.

The algorithms for calculating synthetic seismograms from a dipole source using the derivatives of Green's function

Science.gov (United States)

Pavlov, V. M.

2017-07-01

The problem of calculating complete synthetic seismograms from a point dipole with an arbitrary seismic moment tensor in a plane parallel medium composed of homogeneous elastic isotropic layers is considered. It is established that the solutions of the system of ordinary differential equations for the motion-stress vector have a reciprocity property, which allows obtaining a compact formula for the derivative of the motion vector with respect to the source depth. The reciprocity theorem for Green's functions with respect to the interchange of the source and receiver is obtained for a medium with cylindrical boundary. The differentiation of Green's functions with respect to the coordinates of the source leads to the same calculation formulas as the algorithm developed in the previous work (Pavlov, 2013). A new algorithm appears when the derivatives with respect to the horizontal coordinates of the source is replaced by the derivatives with respect to the horizontal coordinates of the receiver (with the minus sign). This algorithm is more transparent, compact, and economic than the previous one. It requires calculating the wavenumbers associated with Bessel function's roots of order 0 and order 1, whereas the previous algorithm additionally requires the second order roots.

Infrasound Predictions Using the Weather Research and Forecasting Model: Atmospheric Green's Functions for the Source Physics Experiments 1-6.

Energy Technology Data Exchange (ETDEWEB)

Poppeliers, Christian; Aur, Katherine Anderson; Preston, Leiph

2018-03-01

This report shows the results of constructing predictive atmospheric models for the Source Physics Experiments 1-6. Historic atmospheric data are combined with topography to construct an atmo- spheric model that corresponds to the predicted (or actual) time of a given SPE event. The models are ultimately used to construct atmospheric Green's functions to be used for subsequent analysis. We present three atmospheric models for each SPE event: an average model based on ten one- hour snap shots of the atmosphere and two extrema models corresponding to the warmest, coolest, windiest, etc. atmospheric snap shots. The atmospheric snap shots consist of wind, temperature, and pressure profiles of the atmosphere for a one-hour time window centered at the time of the predicted SPE event, as well as nine additional snap shots for each of the nine preceding years, centered at the time and day of the SPE event.

Few-particle quantum dynamics–comparing nonequilibrium Green functions with the generalized Kadanoff–Baym ansatz to density operator theory

International Nuclear Information System (INIS)

Hermanns, S; Bonitz, M; Balzer, K

2013-01-01

The nonequilibrium description of quantum systems requires, for more than two or three particles, the use of a reduced description to be numerically tractable. Two possible approaches are based on either reduced density matrices or nonequilibrium Green functions (NEGF). Both concepts are formulated in terms of hierarchies of coupled equations—the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy for the reduced density operators and the Martin-Schwinger-hierarchy (MS) for the Green functions, respectively. In both cases, similar approximations are introduced to decouple the hierarchy, yet still many questions regarding the correspondence of both approaches remain open. Here we analyze this correspondence by studying the generalized Kadanoff–Baym ansatz (GKBA) that reduces the NEGF to a single-time theory. Starting from the BBGKY-hierarchy we present the approximations that are necessary to recover the GKBA result both, with Hartree-Fock propagators (HF-GKBA) and propagators in second Born approximation. To test the quality of the HF-GKBA, we study the dynamics of a 4-electron Hubbard nanocluster starting from a strong nonequilibrium initial state and compare to exact results and the Wang-Cassing approximation to the BBGKY hierarchy presented recently by Akbari et al. [1].

A DATABASE OF >20 keV ELECTRON GREEN'S FUNCTIONS OF INTERPLANETARY TRANSPORT AT 1 AU

Energy Technology Data Exchange (ETDEWEB)

Agueda, N.; Sanahuja, B. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos, Universitat de Barcelona, Barcelona (Spain); Vainio, R. [Department of Physics, University of Helsinki, Helsinki (Finland)

2012-10-15

We use interplanetary transport simulations to compute a database of electron Green's functions, i.e., differential intensities resulting at the spacecraft position from an impulsive injection of energetic (>20 keV) electrons close to the Sun, for a large number of values of two standard interplanetary transport parameters: the scattering mean free path and the solar wind speed. The nominal energy channels of the ACE, STEREO, and Wind spacecraft have been used in the interplanetary transport simulations to conceive a unique tool for the study of near-relativistic electron events observed at 1 AU. In this paper, we quantify the characteristic times of the Green's functions (onset and peak time, rise and decay phase duration) as a function of the interplanetary transport conditions. We use the database to calculate the FWHM of the pitch-angle distributions at different times of the event and under different scattering conditions. This allows us to provide a first quantitative result that can be compared with observations, and to assess the validity of the frequently used term beam-like pitch-angle distribution.

Green Transformational Leadership and Green Performance: The Mediation Effects of Green Mindfulness and Green Self-Efficacy

OpenAIRE

Yu-Shan Chen; Ching-Hsun Chang; Yu-Hsien Lin

2014-01-01

No prior literature explores the influence of green transformational leadership on green performance, thus, this study develops a novel research framework to fill the research gap. This study investigates the influence of green transformational leadership on green performance and discusses the mediation effects of green mindfulness and green self-efficacy by means of structural equation modeling (SEM). The results indicate that green transformational leadership positively influences green min...

Modification of functional quality of beer by using microencapsulated green tea (Camellia sinensis L. and Ganoderma mushroom (Ganoderma lucidum L. bioactive compounds

Directory of Open Access Journals (Sweden)

Belščak-Cvitanović Ana

2017-01-01

Full Text Available Increasing interest in production of frequently consumed functional food products has focused the present study on implementation of microencapsulated Ganoderma mushroom and green tea bioactive compounds in beer production. Electrostatic extrusion assisted microencapsulation of green tea and Ganoderma extracts enabled production of particles ranging from 490 to 1000 μm in size, with up to 75% of entrapped total polyphenols. Dried, powdered extracts, as well as microparticles encapsulating Ganoderma and green tea extracts that exhibited the best morphological properties and retarded release of polyphenols (alginate and alginate-chitosan coated, as well as chitosan coated pectin microbeads were implemented in beer production. The addition of Ganoderma microbeads to pilsner beer did not augment its polyphenolic concentration (TPC, as opposed to the addition of green tea encapsulating microbeads to radler, while adding dried Ganoderma and spray dried green tea extracts enabled to increase the TPC for up to 3-fold higher values. Ganoderma dried extract-enriched pilsner beer and spray dried green tea extract-enriched radler were preferred in terms of sensory properties, due to the lowest bitterness intensity and most pronounced herbal aroma of the added adjuncts. Refrigerated storage of Ganoderma hydrogel microbeads-enriched pilsner beer revealed fluctuations of TPC, while green tea hydrogel microbeads-enriched radler exhibited better stability. The established methodology provides a procedure suitable for microencapsulate-enrichment of drink and food products, thus setting a reliable basis for future functional food production by microencapsulate implementation strategies. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46001, Grant no. 46010 and Grant no. 31020

Method of the reduced-added Green function in the calculation of atomic polarizabilities

International Nuclear Information System (INIS)

Chernov, V.E.; Dorofeev, D.L.; Kretinin, I.Yu.; Zon, B.A.

2005-01-01

The Green function in the quantum defect theory provides an exact account for high-excited and continuum electronic states. We modify it by taking into account the ground and low-excited states using their wave functions calculated ab initio. As an application, we present a simple and efficient semianalytical method for the calculation of atomic electric frequency-dependent scalar dipole polarizability, for both real and imaginary frequencies. The polarizabilities calculated for some atoms (Li, Na, K, Be, Mg, Ca, Si, P, S, O, Al, Ge, C, N, F, He, Ne, Ar, Kr, and Xe) are compared with existing methods of computational quantum chemistry and with experiments; good accuracy of the proposed method is demonstrated

Green's function for electrons in a narrow quantum well in a parallel magnetic field

International Nuclear Information System (INIS)

Horing, Norman J. Morgenstern; Glasser, M. Lawrence; Dong Bing

2005-01-01

Electron dynamics in a narrow quantum well in a parallel magnetic field of arbitrary strength are examined here. We derive an explicit analytical closed-form solution for the Green's function of Landau-quantized electrons in skipping states of motion between the narrow well walls coupled with in-plane translational motion and hybridized with the zero-field lowest subband energy eigenstate. Such Landau-quantized modes are not uniformly spaced

The gluon Green's function in the BFKL approach at next-to-leading logarithmic accuracy

International Nuclear Information System (INIS)

Andersen, Jeppe R.; Sabio Vera, Agustin

2004-01-01

We investigate the gluon Green's function in the high energy limit of QCD using a recently proposed iterative solution of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation at next-to-leading logarithmic (NLL) accuracy. To establish the applicability of this method in the NLL approximation we solve the BFKL equation as originally written by Fadin and Lipatov, and compare the results with previous studies in the leading logarithmic (LL) approximation

New Integrated Quality Function Deployment Approach Based on Interval Neutrosophic Set for Green Supplier Evaluation and Selection

Directory of Open Access Journals (Sweden)

Luu Huu Van

2018-03-01

Full Text Available Green supplier evaluation and selection plays a crucial role in the green supply chain management of any organization to reduce the purchasing cost of materials and increase the flexibility and quality of products. An interval neutrosophic set (INS—which is a generalization of fuzzy sets, intuitionistic fuzzy sets (IFS and neutrosophic sets (NS—can better handle the incomplete, indeterminate and inconsistent information than the other sets. This paper proposes a new integrated Quality Function Deployment (QFD in support of the green supplier evaluation and selection process. In the proposed approach, INS is used to assess the relative importance of the characteristics that the purchased product should have (internal variables “WHATs” in order to satisfy the company’s needs, the relevant supplier assessment criteria (external variables “HOWs”, the “HOWs”-“WHATs” correlation scores, the resulting weights of the “HOWs” and the impact of each potential supplier. The normalized weighted rating is then defined and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS method is developed to obtain a final ranking of green suppliers. A case study is applied to demonstrate the efficiency and computational procedure of the proposed method.

Use of the Green function method for calculation of cross section of x-ray photoabsorption for solids

International Nuclear Information System (INIS)

Kozhakhmetov, S.K.

1996-01-01

Possibility of Green formalism use for calculation of photoabsorption of high-energy x-ray radiation is shown. Analytical expression for photoabsorption cross section is carried out. It does not contains wave functions in explicit form responding to finite states of photoelectron. 5 refs

Evaluation of Water Efficiency in Green Building in Taiwan

Directory of Open Access Journals (Sweden)

Cheng-Li Cheng

2016-06-01

Full Text Available Low carbon policies, including those aimed at increasing water efficiency, have been adopted as a crucial strategy for combating global warming and climate change. The green building evaluation system used in Taiwan was first applied in 1999 and initially utilized a building’s water efficiency as the threshold index for determining the building’s environmental impact. Since 1999, more than a thousand buildings have been certified as green buildings using this evaluation system. The quantitative effects of water conservation efforts should be provided to policy makers as a form of positive feedback. To that end, the present study offers a calculation process for estimating the quantitative volume of water saved by practical green buildings. The baseline water usage for all kinds of buildings was determined to serve as the criterion for determining the water-saving efficiency of individual buildings. An investigation of the average water-saving rate from 2000 to 2013 for 1320 buildings certified as green buildings was also conducted to validate the estimation results and found that these green buildings saved an average of approximately 37.6% compared to the baseline water usage rate for all buildings. Water savings will inevitably follow from the use of water-saving appliances or water-saving designs for buildings. The proposed calculation process can be used to clarify the relationships between specific water-saving concepts and the real water usage efficiency of green buildings.

When Oil and Wind Turbine Companies Make Green Sense Together

DEFF Research Database (Denmark)

Backer, Lise

strengthen their relationships with companies such as Vestas - that are born green. This is so, since companies that are born green have strong green ecocentric business beliefs that can function as important engines in shared green sense-making with companies that are not born green and have more hesitant...... green beliefs....

Carrier transport in THz quantum cascade lasers: Are Green's functions necessary?

Energy Technology Data Exchange (ETDEWEB)

Matyas, A; Jirauschek, C [Emmy Noether Research Group ' Modeling of Quantum Cascade Devices' , TU Muenchen, D-80333 Muenchen (Germany); Kubis, T [Walter Schottky Institute, TU Muenchen, D-85748 Garching (Germany); Lugli, P, E-mail: alparmat@mytum.d [Institute of Nanoelectronics, TU Muenchen, D-80333 Muenchen (Germany)

2009-11-15

We have applied two different simulation models for the stationary carrier transport and optical gain analysis in resonant phonon depopulation THz Quantum Cascade Lasers (QCLs), based on the semiclassical ensemble Monte Carlo (EMC) and fully quantum mechanical non-equilibrium Green's functions (NEGF) method, respectively. We find in the incoherent regime near and above the threshold current a qualitative and quantitative agreement of both methods. Therefore, we show that THz-QCLs can be successfully optimized utilizing the numerically efficient EMC method.

GREEN PACKAGING, GREEN PRODUCT, GREEN ADVERTISING, PERSEPSI, DAN MINAT BELI KONSUMEN

Directory of Open Access Journals (Sweden)

Imam Santoso

2016-12-01

Full Text Available Environmental problems become one of the strategic issues in achieving global competitiveness. One of the issues is products that are made from environmental friendly materials or known as green product. Furthermore, in green products marketing, the company also uses green packaging and green advertising concept. This study aimed to analyze the effect of green packaging, green products, and green advertising on consumer perception and purchasing intention. The study was conducted in Ketawanggede Village, Lowokwaru Sub-district, Malang City. The sampling method used nonprobability accidential sampling techniques. The numbers of respondents were 113 consumers in study site. Data were collected by interview using questionnaires. The method of analysis used Generalized Structured Component Analysis (GSCA. The analysis showed that the green packaging, green products, and green advertising had positive significant influence on consumer perceptions. Meanwhile, green product and consumer perception had positive significant influence on purchasing interest, but the green packaging and green advertising has not found sufficient evidence in influencing purchasing intention.

Averaging models: parameters estimation with the R-Average procedure

Directory of Open Access Journals (Sweden)

S. Noventa

2010-01-01

Full Text Available The Functional Measurement approach, proposed within the theoretical framework of Information Integration Theory (Anderson, 1981, 1982, can be a useful multi-attribute analysis tool. Compared to the majority of statistical models, the averaging model can account for interaction effects without adding complexity. The R-Average method (Vidotto & Vicentini, 2007 can be used to estimate the parameters of these models. By the use of multiple information criteria in the model selection procedure, R-Average allows for the identification of the best subset of parameters that account for the data. After a review of the general method, we present an implementation of the procedure in the framework of R-project, followed by some experiments using a Monte Carlo method.

Antibacterial activity of propolins from Taiwanese green propolis

Directory of Open Access Journals (Sweden)

Yue-Wen Chen

2018-04-01

Full Text Available Taiwanese green propolis is a prenylated flavonoid rich honeybee product and propolins isolated from Taiwanese green propolis exert a broad spectrum of biological activities, such as anti-cancer and anti-oxidant. However, the anti-bacterial effects of Taiwanese green propolis or propolins are still poorly understood. In the current study, the antibacterial effects of Taiwanese green propolis and propolins were evaluated. Results show that the maximum dry matter yields of Taiwanese green propolis were observed in the 95% and 99.5% ethanol extracts compared to other extraction methods. Consistently, the highest concentration of propolins C, D, F and G from Taiwanese green propolis was obtained in 95% and 99.5% ethanol extracts. Propolins inhibited the growth of gram-positive bacterial strains (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes and Paenibacillus larvae. The average minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC of propolins from ethanol extracts were 20 μg/ml. Among the propolins, propolin C had the highest antibacterial activity. Furthermore, Taiwanese green propolis also showed antibacterial activity against methicillin-resistant S. aureus (MRSA. In conclusion, these results demonstrate that Taiwanese green propolis and propolins have significant antibacterial activity, particularly against gram-positive bacterial strains. Keywords: Antibacterial activity, Propolins, Taiwan, Green propolis

Green function as an integral superposition of Gaussian beams in inhomogeneous anisotropic layered structures in Cartesian coordinates

Czech Academy of Sciences Publication Activity Database

Červený, V.; Pšenčík, Ivan

2016-01-01

Roč. 26 (2016), s. 131-153 ISSN 2336-3827 R&D Projects: GA ČR(CZ) GA16-05237S Institutional support: RVO:67985530 Keywords : elastodynamic Green function * inhomogeneous anisotropic media * integral superposition of Gaussian beams Subject RIV: DC - Siesmology, Volcanology, Earth Structure

Magnetic properties of spinels GeNi2-xCoxO4 systems: Green's function and high-temperature series expansions

Science.gov (United States)

El Grini, A.; Salmi, S.; Masrour, R.; Hamedoun, M.; Bouslykhane, K.; Marzouk, A.; Hourmatallah, A.; Benzakour, N.

2018-06-01

The Green's function theory and high-temperature series expansions technical have been developed for magnetic systems GeNi2-xCoxO4. We have applied the Green's function theory to evaluate thermal magnetization and magnetic susceptibility for different values of magnetic field and dilution x, considering all components of the magnetization when an external magnetic field is applied in (x,z)-plane. The second theory combined with the Padé approximants method for a randomly diluted Heisenberg magnet is used to deduce the magnetic phase diagram of GeNi2 - xCoxO4 systems. The critical exponents ? and ? and associated with the magnetic susceptibility ? and the correlation length ξ, respectively, have been deduced. The theoretical results are compared with those given by magnetic measurements.

Non-equilibrium Green's functions method: Non-trivial and disordered leads

Science.gov (United States)

He, Yu; Wang, Yu; Klimeck, Gerhard; Kubis, Tillmann

2014-11-01

The non-equilibrium Green's function algorithm requires contact self-energies to model charge injection and extraction. All existing approaches assume infinitely periodic leads attached to a possibly quite complex device. This contradicts today's realistic devices in which contacts are spatially inhomogeneous, chemically disordered, and impacting the overall device characteristics. This work extends the complex absorbing potentials method for arbitrary, ideal, or non-ideal leads in atomistic tight binding representation. The algorithm is demonstrated on a Si nanowire with periodic leads, a graphene nanoribbon with trumpet shape leads, and devices with leads of randomly alloyed Si0.5Ge0.5. It is found that alloy randomness in the leads can reduce the predicted ON-state current of Si0.5Ge0.5 transistors by 45% compared to conventional lead methods.

Green functions and dimensional reduction of quantum fields on product manifolds

International Nuclear Information System (INIS)

Haba, Z

2008-01-01

We discuss Euclidean Green functions on product manifolds P=N x M. We show that if M is compact and N is not compact then the Euclidean field on P can be approximated by its zero mode which is a Euclidean field on N. We estimate the remainder of this approximation. We show that for large distances on N the remainder is small. If P=R D-1 x S β , where S β is a circle of radius β, then the result reduces to the well-known approximation of the D-dimensional finite temperature quantum field theory by (D - 1)-dimensional one in the high-temperature limit. Analytic continuation of Euclidean fields is discussed briefly

Market analysis green electricity. Final report

International Nuclear Information System (INIS)

Reichmuth, Matthias

2014-01-01

In the present study the volume of the German market for green energy will be analyzed for its functionality, barriers and also its development perspectives. Besides an evaluation of actual literature sources, elaborate interviews of electricity suppliers (green energy suppliers) were realized.

Accumulation of uranium by filamentous green algae under natural environmental conditions

International Nuclear Information System (INIS)

Aleissa, K.A.; Shabana, El-Said K.; Al-Masoud, F.L.S.

2004-01-01

The capacity of algae to concentrate uranium under natural environmental conditions is measured by a-spectrometry. Spirogyra, a filamentous green fresh-water alga, has concentrated uranium from a surface concrete ponds with elevated uranium levels (140-1140 ppb). The concentration factors (CFs) ranged from 8.9-67 with an average value of 22. Cladophora spp, a filamentous green marine alga has concentrated uranium from the marine water with a concentration factor ranged from 220-280. The average concentration factor was 250. The factors affecting the sorption process are discussed in detail. (author)

GREEN PACKAGING, GREEN PRODUCT, GREEN ADVERTISING, PERSEPSI, DAN MINAT BELI KONSUMEN

OpenAIRE

Imam Santoso; Rengganis Fitriani

2016-01-01

Environmental problems become one of the strategic issues in achieving global competitiveness. One of the issues is products that are made from environmental friendly materials or known as green product. Furthermore, in green products marketing, the company also uses green packaging and green advertising concept. This study aimed to analyze the effect of green packaging, green products, and green advertising on consumer perception and purchasing intention. The study was conducted in Ketawangg...

A first-order Green's function approach to supersonic oscillatory flow: A mixed analytic and numeric treatment

Science.gov (United States)

Freedman, M. I.; Sipcic, S.; Tseng, K.

1985-01-01

A frequency domain Green's Function Method for unsteady supersonic potential flow around complex aircraft configurations is presented. The focus is on the supersonic range wherein the linear potential flow assumption is valid. In this range the effects of the nonlinear terms in the unsteady supersonic compressible velocity potential equation are negligible and therefore these terms will be omitted. The Green's function method is employed in order to convert the potential flow differential equation into an integral one. This integral equation is then discretized, through standard finite element technique, to yield a linear algebraic system of equations relating the unknown potential to its prescribed co-normalwash (boundary condition) on the surface of the aircraft. The arbitrary complex aircraft configuration (e.g., finite-thickness wing, wing-body-tail) is discretized into hyperboloidal (twisted quadrilateral) panels. The potential and co-normalwash are assumed to vary linearly within each panel. The long range goal is to develop a comprehensive theory for unsteady supersonic potential aerodynamic which is capable of yielding accurate results even in the low supersonic (i.e., high transonic) range.

Green leaf volatiles: biosynthesis, biological functions and their applications in biotechnology.

Science.gov (United States)

ul Hassan, Muhammad Naeem; Zainal, Zamri; Ismail, Ismanizan

2015-08-01

Plants have evolved numerous constitutive and inducible defence mechanisms to cope with biotic and abiotic stresses. These stresses induce the expression of various genes to activate defence-related pathways that result in the release of defence chemicals. One of these defence mechanisms is the oxylipin pathway, which produces jasmonates, divinylethers and green leaf volatiles (GLVs) through the peroxidation of polyunsaturated fatty acids (PUFAs). GLVs have recently emerged as key players in plant defence, plant-plant interactions and plant-insect interactions. Some GLVs inhibit the growth and propagation of plant pathogens, including bacteria, viruses and fungi. In certain cases, GLVs released from plants under herbivore attack can serve as aerial messengers to neighbouring plants and to attract parasitic or parasitoid enemies of the herbivores. The plants that perceive these volatile signals are primed and can then adapt in preparation for the upcoming challenges. Due to their 'green note' odour, GLVs impart aromas and flavours to many natural foods, such as vegetables and fruits, and therefore, they can be exploited in industrial biotechnology. The aim of this study was to review the progress and recent developments in research on the oxylipin pathway, with a specific focus on the biosynthesis and biological functions of GLVs and their applications in industrial biotechnology. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Some exact identities connecting one- and two-particle Green's functions in spin-orbit coupling systems

International Nuclear Information System (INIS)

Yang Huatong

2007-01-01

Some exact identities connecting one- and two-particle Green's functions in the presence of spin-orbit coupling have been derived. These identities are similar to the Ward identity in usual quantum transport theory of electrons. A satisfying approximate calculation of the spin transport in spin-orbit coupling system should also preserve these identities, just as the Ward identities should be remained in the usual electronic transport theory

Greens of the European Green Capitals

Science.gov (United States)

Cömertler, Seval

2017-10-01

Well established and maintained green areas have a key role on reaching the high quality of life and sustainability in urban environments. Therefore, green areas must be carefully accounted and evaluated in the urban planning affairs. In this context, the European Green Capitals, which attach a great importance to the green areas, have a great potential to act as a role model for both small and big cities in all around the world. These leading cities (chronologically, Stockholm, Hamburg, Vitoria-Gasteiz, Nantes, Copenhagen, Bristol, Ljubljana, Essen and Nijmegen) are inspiring for the other cities which seek to achieve more sustainable and environmentally friendly places through green areas. From this point of view, the aim of this paper was to investigate the green areas of the European Green Capitals. The paper covered whole European Green Capitals, and the application form of each Green Capital was used as a primary data source. Consequently, the paper put forwarded that the European Green Capitals have considerably large amount and high proportion of green areas. Further, these cities provide an excellent access to the public green areas. As a result of abundant provision and proper distribution, the almost all citizens in most of the Green Capitals live within a distance of 300 meters to a green area. For further researches, the paper suggested that these green capitals should be investigated in terms of their efforts, measures, goals and plans, policies and implications to administer, to protect, to enhance and to expand the green areas.

18 CFR 301.7 - Average System Cost methodology functionalization.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Average System Cost... REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS FOR FEDERAL POWER MARKETING ADMINISTRATIONS AVERAGE SYSTEM COST METHODOLOGY FOR SALES FROM UTILITIES TO BONNEVILLE POWER ADMINISTRATION UNDER NORTHWEST POWER...

Retrieving the elastodynamic Green's function of an arbitrary inhomogeneous medium by cross correlation

International Nuclear Information System (INIS)

Wapenaar, Kees

2004-01-01

A correlation-type reciprocity theorem is used to show that the elastodynamic Green's function of any inhomogeneous medium (random or deterministic) can be retrieved from the cross correlation of two recordings of a wave field at different receiver locations at the free surface. Unlike in other derivations, which apply to diffuse wave fields in random media or irregular finite bodies, no assumptions are made about the diffusivity of the wave field. In a second version, it is assumed that the wave field is diffuse due to many uncorrelated sources inside the medium

A Green's function solution for a rectangular heat source on an infinite plate

International Nuclear Information System (INIS)

Bainbridge, B.L.

1989-01-01

The applications associated with a rectangular heat source on an infinite plate range from integrated circuits to thin film heat flux sensors on thin substrates. The particular problem from which the solution is developed concerns the use of a resistive strip for monitoring currents generated in circuits exposed to electromagnetic fields. The Green's function formulation is solved by using early and late time approximations for which analytical solutions can be derived. In this paper expressions are developed for three sets of boundary conditions and compared to the experimental performance of a physical device

Analysis of Green's functions and stability problem in models of quantum field theory with solitons

International Nuclear Information System (INIS)

Raczka, R.; Roszkowski, L.

1983-10-01

A class of models of quantum field theory for a multiplet phi-vector=(phi 1 ,...,phisub(N)) of real scalar fields, possessing a particle-like classical solution phi-vector 0 , is considered. A new formula for generating functional for time-ordered Green's functions in terms of effective propagators is derived. The problem of classical and quantum stability is analyzed in detail. It is shown by partly non-perturbative analysis that in the considered models the excited states of mesons do exist and form the trajectories in the plane mass 2 -spin. These trajectories are linear or approximately linear like experimental trajectories. (author)

Suggestions on Strengthening Greening Construction of Ecological Residential Areas

OpenAIRE

Li, Peng

2013-01-01

Greening construction is an important part of the construction of ecological residential areas, but there exist some misunderstandings in greening construction of ecological residential districts at present. Based on the description of functions of green space in ecological residential areas, the summarization of principles of greening design, and the discussion of questions in greening construction of ecological residential districts, some suggestions as well as specific measures for strengt...

Average biomass of four Northwest shrubs by fuel size class and crown cover.

Science.gov (United States)

Robert E. Martin; David W. Frewing; James L. McClanahan

1981-01-01

The average biomass of big sagebrush (Artemisia tridentata Nutt.), antelope bitterbrush (Purshia tridentata (Pursh) DC.), snowbrush ceanothus (Ceanothus velutinus Dougl. ex Hook.), and greenleaf manzanita (Arctostaphylos patula Greene) was 6.1, 5.1, 10.7, and 16.2 tons per acre (13.9,...

Nonequilibrium Green's function method for quantum thermal transport

Science.gov (United States)

Wang, Jian-Sheng; Agarwalla, Bijay Kumar; Li, Huanan; Thingna, Juzar

2014-12-01

This review deals with the nonequilibrium Green's function (NEGF) method applied to the problems of energy transport due to atomic vibrations (phonons), primarily for small junction systems. We present a pedagogical introduction to the subject, deriving some of the well-known results such as the Laudauer-like formula for heat current in ballistic systems. The main aim of the review is to build the machinery of the method so that it can be applied to other situations, which are not directly treated here. In addition to the above, we consider a number of applications of NEGF, not in routine model system calculations, but in a few new aspects showing the power and usefulness of the formalism. In particular, we discuss the problems of multiple leads, coupled left-right-lead system, and system without a center. We also apply the method to the problem of full counting statistics. In the case of nonlinear systems, we make general comments on the thermal expansion effect, phonon relaxation time, and a certain class of mean-field approximations. Lastly, we examine the relationship between NEGF, reduced density matrix, and master equation approaches to thermal transport.

Green's functions for theories with massless particles (in perturbation theory). [Growth properties, momentum space, mass renormalization

Energy Technology Data Exchange (ETDEWEB)

Blanchard, P [European Organization for Nuclear Research, Geneva (Switzerland); Seneor, R [European Organization for Nuclear Research, Geneva (Switzerland); Ecole Polytechnique, 75 - Paris (France). Centre de Physique Theorique)

1975-01-01

With the method of perturbative renormalization developed by Epstein and Glaser it is shown that Green's functions exist for theories with massless particles such as Q.E.D. and lambda:PHI/sup 2n/ theories. Growth properties are given in momentum space. In the case of Q.E.D., it is also shown that one can perform the physical mass renormalization.

The Influence of Proactive Green Innovation and Reactive Green Innovation on Green Product Development Performance: The Mediation Role of Green Creativity

Directory of Open Access Journals (Sweden)

Yu-Shan Chen

2016-09-01

Full Text Available This study fills the research gap in the exploration of the relationships between both proactive and reactive green innovations and green product development performance, and examines the mediating effect of green creativity. Structural equation modeling (SEM is utilized to test the hypotheses. From the sample of 146 valid respondents, the results show that proactive green innovation positively affects green creativity and green product development performance, and green creativity positively affects green product development performance. In addition, our findings also indicate that the relationship between proactive green innovation and green product development performance is partially mediated by green creativity. Accordingly, green creativity plays a critical role for companies to achieve a great green product development performance. However, reactive green innovation does not significantly influence green creativity and green product development performance. Companies should develop proactive green innovation rather than reactive green innovation in order to enhance their green creativity and increase their product development performance.

Calculation of anomalous dimension of single-particle Green function in scalar field theory with strong nonlinear interaction

International Nuclear Information System (INIS)

Kolesnichenko, A.V.

1980-01-01

An expression for the anomalous dimension of the single-particle Green function is derived in the scalar theory with the interaction Hamiltonian Hsub(int)=g(phisup(n)/n) in the limit n→infinity. It is simultaneously shown that in this model the range of essential distances is of order of nsup(-1/2)

Representing nature : Late twentieth century green infrastructures in Paris

NARCIS (Netherlands)

Van der Velde, J.R.T.; De Wit, S.I.

2015-01-01

The appreciation of green infrastructures as ‘nature’ by urban communities presents a critical challenge for the green infrastructure concept. While many green infrastructures focus on functional considerations, their refinement as places where concepts of nature are represented and where nature can

Use of small public urban green spaces (SPUGS)

DEFF Research Database (Denmark)

Peschardt, Karin Kragsig; Schipperijn, Jasper; Stigsdotter, Ulrika K.

2012-01-01

which environmental characteristics users prefer in relation to mental restoration. We investigate nine small public urban green spaces (SPUGS) in the dense city of Copenhagen in order to determine which environmental characteristics may influence the perceived restorativeness of SPUGS amongst average......UGS have been positively associated with stress-related illnesses. Paradoxically the densification tendency in western cities causes decreasing access to green environments. City planners and landscape architects are challenged when designing such areas due to a lack of space and knowledge about...

Developing resilient green roofs in a dry climate.

Science.gov (United States)

Razzaghmanesh, M; Beecham, S; Brien, C J

2014-08-15

Living roofs are an emerging green infrastructure technology that can potentially be used to ameliorate both climate change and urban heat island effects. There is not much information regarding the design of green roofs for dry climates and so the aim of this study was to develop low maintenance and unfertilized green roofs for a dry climate. This paper describes the effects of four important elements of green roofs namely slope, depth, growing media and plant species and their possible interactions in terms of plant growth responses in a dry climate. Sixteen medium-scale green roofs were set up and monitored during a one year period. This experiment consisted of twelve vegetated platforms and four non-vegetated platforms as controls. The design for the experiment was a split-split-plot design in which the factors Slope (1° and 25°) and Depth (100mm, 300 mm) were randomized to the platforms (main plots). Root depth and volume, average height of plants, final dry biomass and ground cover, relative growth rate, final dry shoot-root ratio, water use efficiency and leaf succulence were studied during a twelve month period. The results showed little growth of the plants in media type A, whilst the growth was significant in both media types B and C. On average, a 90% survival rate of plants was observed. Also the growth indices indicated that some plants can grow efficiently in the harsh environment created by green roofs in a dry climate. The root growth pattern showed that retained water in the drainage layer is an alternative source of water for plants. It was also shown that stormwater can be used as a source of irrigation water for green roofs during six months of the year at the study site. In summary, mild sloping intensive systems containing media type C and planted with either Chrysocephalum apiculatum or Disphyma crassifolium showed the best performance. Copyright © 2014 Elsevier B.V. All rights reserved.

Integral relations in complex space and the global analytic and monodromic structure of Green's functions in quantum field theory

International Nuclear Information System (INIS)

Bros, J.

1980-01-01

In this lecture, we present some of the ideas of a global consistent approach to the analytic and monodromic structure of Green's functions and scattering amplitudes of elementary particles on the basis of general quantum field theory. (orig.)

Pengaruh Green Marketing Hotel Terhadap Green Consumer Behavior

OpenAIRE

Yo Fernandez, Eunike Christe; Tjoanda, Evelyn

2017-01-01

Penelitian ini dilakukan untuk mengetahui pengaruh dari green marketing hotel terhadap green consumer behavior. Green marketing memiliki 3 dimensi, yaitu green product, green price, dan green promotion. Penelitian ini melibatkan 272 responden masyarakat Surabaya dan menggunakan metode regresi linear berganda. Hasil penelitian menunjukkan bahwa green product dan green price berpengaruh secara positif dan signifikan sedangkan green promotion berpengaruh namun tidak signifikan terhadap green con...

Low-rank canonical-tensor decomposition of potential energy surfaces: application to grid-based diagrammatic vibrational Green's function theory

International Nuclear Information System (INIS)

Rai, Prashant; Sargsyan, Khachik; Najm, Habib; Hermes, Matthew R.; Hirata, So

2017-01-01

Here, a new method is proposed for a fast evaluation of high-dimensional integrals of potential energy surfaces (PES) that arise in many areas of quantum dynamics. It decomposes a PES into a canonical low-rank tensor format, reducing its integral into a relatively short sum of products of low-dimensional integrals. The decomposition is achieved by the alternating least squares (ALS) algorithm, requiring only a small number of single-point energy evaluations. Therefore, it eradicates a force-constant evaluation as the hotspot of many quantum dynamics simulations and also possibly lifts the curse of dimensionality. This general method is applied to the anharmonic vibrational zero-point and transition energy calculations of molecules using the second-order diagrammatic vibrational many-body Green's function (XVH2) theory with a harmonic-approximation reference. In this application, high dimensional PES and Green's functions are both subjected to a low-rank decomposition. Evaluating the molecular integrals over a low-rank PES and Green's functions as sums of low-dimensional integrals using the Gauss–Hermite quadrature, this canonical-tensor-decomposition-based XVH2 (CT-XVH2) achieves an accuracy of 0.1 cm -1 or higher and nearly an order of magnitude speedup as compared with the original algorithm using force constants for water and formaldehyde.

Removal of malachite green by adsorption and precipitation using aminopropyl functionalized magnesium phyllosilicate

International Nuclear Information System (INIS)

Lee, Young-Chul; Kim, Eui Jin; Yang, Ji-Won; Shin, Hyun-Jae

2011-01-01

Highlights: → Preparation of aminopropyl functionalized magnesium phyllosilicate (AMP clay). → Characterization of AMP clay and AMP clay-malachite green (MG) mixture. → Novel precipitation mechanism including MG fading plus collapsed AMP clay. → Adsorption kinetics and thermodynamics of MG using AMP clay. - Abstract: We report a method for the removal of malachite green (MG) by adsorption and precipitation using nano-sized aminopropyl functionalized magnesium phyllosilicate (AMP) clay. MG, which is used in aquaculture and fisheries, is a carcinogenic and mutagenic compound. In response to these health risks, many efforts have been focused on adsorption of MG onto various adsorbents, which is a versatile and widely used technique for removing MG from water. Herein, we describe the adsorption and precipitation of MG using AMP clay, as well as the alkaline fading phenomenon of MG. In this study, prepared AMP clay and the precipitate product after the reaction of MG-AMP clay mixture were characterized. In addition, adsorption isotherms and kinetics, as well as thermodynamic studies are presented. Based on the results, we suggest a macro- and microscopic removal mechanism for the adsorption and precipitation of MG using AMP clay. An AMP clay dosage of 0.1 mg mL -1 exhibited a maximum removal capacity of 334.80 mg g -1 and 81.72% MG removal efficiency. With further increases of the AMP clay dosage, removal capacity by AMP clay gradually decreased; at dosage above 0.2 mg mL -1 of AMP clay, the removal efficiency reached 100%.

Removal of malachite green by adsorption and precipitation using aminopropyl functionalized magnesium phyllosilicate

Energy Technology Data Exchange (ETDEWEB)

Lee, Young-Chul [Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Eui Jin [Department of Chemical and Biochemical Engineering, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of); Yang, Ji-Won [Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Shin, Hyun-Jae, E-mail: shinhj@chosun.ac.kr [Department of Chemical and Biochemical Engineering, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of)

2011-08-15

Highlights: {yields} Preparation of aminopropyl functionalized magnesium phyllosilicate (AMP clay). {yields} Characterization of AMP clay and AMP clay-malachite green (MG) mixture. {yields} Novel precipitation mechanism including MG fading plus collapsed AMP clay. {yields} Adsorption kinetics and thermodynamics of MG using AMP clay. - Abstract: We report a method for the removal of malachite green (MG) by adsorption and precipitation using nano-sized aminopropyl functionalized magnesium phyllosilicate (AMP) clay. MG, which is used in aquaculture and fisheries, is a carcinogenic and mutagenic compound. In response to these health risks, many efforts have been focused on adsorption of MG onto various adsorbents, which is a versatile and widely used technique for removing MG from water. Herein, we describe the adsorption and precipitation of MG using AMP clay, as well as the alkaline fading phenomenon of MG. In this study, prepared AMP clay and the precipitate product after the reaction of MG-AMP clay mixture were characterized. In addition, adsorption isotherms and kinetics, as well as thermodynamic studies are presented. Based on the results, we suggest a macro- and microscopic removal mechanism for the adsorption and precipitation of MG using AMP clay. An AMP clay dosage of 0.1 mg mL{sup -1} exhibited a maximum removal capacity of 334.80 mg g{sup -1} and 81.72% MG removal efficiency. With further increases of the AMP clay dosage, removal capacity by AMP clay gradually decreased; at dosage above 0.2 mg mL{sup -1} of AMP clay, the removal efficiency reached 100%.

Establishing green roof infrastructure through environmental policy instruments.

Science.gov (United States)

Carter, Timothy; Fowler, Laurie

2008-07-01

Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated