Topology of actions and homogeneous spaces

International Nuclear Information System (INIS)

Kozlov, Konstantin L

2013-01-01

Topologization of a group of homeomorphisms and its action provide additional possibilities for studying the topological space, the group of homeomorphisms, and their interconnections. The subject of the paper is the use of the property of d-openness of an action (introduced by Ancel under the name of weak micro-transitivity) in the study of spaces with various forms of homogeneity. It is proved that a d-open action of a Čech-complete group is open. A characterization of Polish SLH spaces using d-openness is given, and it is established that any separable metrizable SLH space has an SLH completion that is a Polish space. Furthermore, the completion is realized in coordination with the completion of the acting group with respect to the two-sided uniformity. A sufficient condition is given for extension of a d-open action to the completion of the space with respect to the maximal equiuniformity with preservation of d-openness. A result of van Mill is generalized, namely, it is proved that any homogeneous CDH metrizable compactum is the only G-compactification of the space of rational numbers for the action of some Polish group. Bibliography: 39 titles.

Analysis of a homogenous and heterogeneous stylized half core of a CANDU reactor

Energy Technology Data Exchange (ETDEWEB)

EL-Khawlani, Afrah [Physics Department, Sana' a (Yemen); Aziz, Moustafa [Nuclear and radiological regulatory authority, Cairo (Egypt); Ismail, Mahmud Yehia; Ellithi, Ali Yehia [Cairo Univ. (Egypt). Faculty of Science

2015-03-15

The MCNPX (Monte Carlo N-Particle Transport Code System) code has been used for modeling and simulation of a half core of CANDU (CANada Deuterium-Uranium) reactor, both homogenous and heterogeneous model for the reactor core are designed. The fuel is burnt in normal operation conditions of CANDU reactors. Natural uranium fuel is used in the model. The multiplication factor for homogeneous and heterogeneous reactor core is calculated and compared during fuel burnup. The concentration of both uranium and plutonium isotopes are analysed in the model. The flux and power distributions through channels are calculated.

The Effect of Magnetic Field and Initial Stress on Fractional Order Generalized Thermoelastic Half-Space

Directory of Open Access Journals (Sweden)

Sunita Deswal

2013-01-01

Full Text Available The aim of this paper is to study magneto-thermoelastic interactions in an initially stressed isotropic homogeneous half-space in the context of fractional order theory of generalized thermoelasticity. State space formulation with the Laplace transform technique is used to obtain the general solution, and the resulting formulation is applied to the ramp type increase in thermal load and zero stress. Solutions of the problem in the physical domain are obtained by using a numerical method of the Laplace inverse transform based on the Fourier expansion technique, and the expressions for the displacement, temperature, and stress inside the half-space are obtained. Numerical computations are carried out for a particular material for illustrating the results. Results obtained for the field variables are displayed graphically. Some comparisons have been shown in figures to present the effect of fractional parameter, ramp parameter, magnetic field, and initial stress on the field variables. Some particular cases of special interest have been deduced from the present investigation.

Quasi-Rayleigh waves in transversely isotropic half-space with inclined axis of symmetry

International Nuclear Information System (INIS)

Yanovskaya, T.B.; Savina, L.S.

2003-09-01

A method for determination of characteristics of quasi-Rayleigh (qR) wave in a transversely isotropic homogeneous half-space with inclined axis of symmetry is outlined. The solution is obtained as a superposition of qP, qSV and qSH waves, and surface wave velocity is determined from the boundary conditions at the free surface and at infinity, as in the case of Rayleigh wave in isotropic half-space. Though the theory is simple enough, a numerical procedure for the calculation of surface wave velocity presents some difficulties. The difficulty is conditioned by necessity to calculate complex roots of a non-linear equation, which in turn contains functions determined as roots of nonlinear equations with complex coefficients. Numerical analysis shows that roots of the equation corresponding to the boundary conditions do not exist in the whole domain of azimuths and inclinations of the symmetry axis. The domain of existence of qR wave depends on the ratio of the elastic parameters: for some strongly anisotropic models the wave cannot exist at all. For some angles of inclination qR wave velocities deviate from those calculated on the basis of the perturbation method valid for weak anisotropy, though they have the same tendency of variation with azimuth. The phase of qR wave varies with depth unlike Rayleigh wave in isotropic half-space. Unlike Rayleigh wave in isotropic half-space, qR wave has three components - vertical, radial and transverse. Particle motion in horizontal plane is elliptic. Direction of the major axis of the ellipsis coincide with the direction of propagation only in azimuths 0 deg. (180 deg.) and 90 deg. (270 deg.). (author)

Relativistic cosmologies with closed, locally homogeneous space sections

International Nuclear Information System (INIS)

Fagundes, H.V.

1985-01-01

The homogeneous Bianchi and Kantowski-Sachs metrics of relativistic cosmology are investigated through their correspondence with recent geometrical results of Thurston. These allow a partial classification of the topologies for closed, locally homogeneous spaces according to Thurston's eight geometric types. Besides, which of the Bianchi-Kantowski-Sachs metrics can be imposed on closed space sections of cosmological models are learned. This is seen as a progress toward implementation of a postulate of the closure of space for both classical and quantum gravity. (Author) [pt

Homogeneous Finsler Spaces

CERN Document Server

Deng, Shaoqiang

2012-01-01

"Homogeneous Finsler Spaces" is the first book to emphasize the relationship between Lie groups and Finsler geometry, and the first to show the validity in using Lie theory for the study of Finsler geometry problems. This book contains a series of new results obtained by the author and collaborators during the last decade. The topic of Finsler geometry has developed rapidly in recent years. One of the main reasons for its surge in development is its use in many scientific fields, such as general relativity, mathematical biology, and phycology (study of algae). This monograph introduc

Analysis of the moments of the sensitivity function for resistivity over a homogeneous half-space: Rules of thumb for pseudoposition, offline sensitivity and resolution

Science.gov (United States)

Butler, S. L.

2017-08-01

It is instructive to consider the sensitivity function for a homogeneous half space for resistivity since it has a simple mathematical formula and it does not require a priori knowledge of the resistivity of the ground. Past analyses of this function have allowed visualization of the regions that contribute most to apparent resistivity measurements with given array configurations. The horizontally integrated form of this equation gives the sensitivity function for an infinitesimally thick horizontal slab with a small resistivity contrast and analysis of this function has admitted estimates of the depth of investigation for a given electrode array. Recently, it has been shown that the average of the vertical coordinate over this function yields a simple formula that can be used to estimate the depth of investigation. The sensitivity function for a vertical inline slab has also been previously calculated. In this contribution, I show that the sensitivity function for a homogeneous half-space can also be integrated so as to give sensitivity functions to semi-infinite vertical slabs that are perpendicular to the array axis. These horizontal sensitivity functions can, in turn, be integrated over the spatial coordinates to give the mean horizontal positions of the sensitivity functions. The mean horizontal positions give estimates for the centres of the regions that affect apparent resistivity measurements for arbitrary array configuration and can be used as horizontal positions when plotting pseudosections even for non-collinear arrays. The mean of the horizontal coordinate that is perpendicular to a collinear array also gives a simple formula for estimating the distance over which offline resistivity anomalies will have a significant effect. The root mean square (rms) widths of the sensitivity functions are also calculated in each of the coordinate directions as an estimate of the inverse of the resolution of a given array. For depth and in the direction perpendicular

Collision-free gases in spatially homogeneous space-times

International Nuclear Information System (INIS)

Maartens, R.; Maharaj, S.D.

1985-01-01

The kinematical and dynamical properties of one-component collision-free gases in spatially homogeneous, locally rotationally symmetric (LRS) space-times are analyzed. Following Ray and Zimmerman [Nuovo Cimento B 42, 183 (1977)], it is assumed that the distribution function f of the gas inherits the symmetry of space-time, in order to construct solutions of Liouville's equation. The redundancy of their further assumption that f be based on Killing vector constants of the motion is shown. The Ray and Zimmerman results for Kantowski--Sachs space-time are extended to all spatially homogeneous LRS space-times. It is shown that in all these space-times the kinematic average four-velocity u/sup i/ can be tilted relative to the homogeneous hypersurfaces. This differs from the perfect fluid case, in which only one space-time admits tilted u/sup i/, as shown by King and Ellis [Commun. Math. Phys. 31, 209 (1973)]. As a consequence, it is shown that all space-times admit nonzero acceleration and heat flow, while a subclass admits nonzero vorticity. The stress π/sub i/j is proportional to the shear sigma/sub i/j by virtue of the invariance of the distribution function. The evolution of tilt and the existence of perfect fluid solutions is also discussed

LibHalfSpace: A C++ object-oriented library to study deformation and stress in elastic half-spaces

Science.gov (United States)

Ferrari, Claudio; Bonafede, Maurizio; Belardinelli, Maria Elina

2016-11-01

The study of deformation processes in elastic half-spaces is widely employed for many purposes (e.g. didactic, scientific investigation of real processes, inversion of geodetic data, etc.). We present a coherent programming interface containing a set of tools designed to make easier and faster the study of processes in an elastic half-space. LibHalfSpace is presented in the form of an object-oriented library. A set of well known and frequently used source models (Mogi source, penny shaped horizontal crack, inflating spheroid, Okada rectangular dislocation, etc.) are implemented to describe the potential usage and the versatility of the library. The common interface given to library tools enables us to switch easily among the effects produced by different deformation sources that can be monitored at the free surface. Furthermore, the library also offers an interface which simplifies the creation of new source models exploiting the features of object-oriented programming (OOP). These source models can be built as distributions of rectangular boundary elements. In order to better explain how new models can be deployed some examples are included in the library.

Quantum groups and quantum homogeneous spaces

International Nuclear Information System (INIS)

Kulish, P.P.

1994-01-01

The usefulness of the R-matrix formalism and the reflection equations is demonstrated on examples of the quantum group covariant algebras (quantum homogeneous spaces): quantum Minkowski space-time, quantum sphere and super-sphere. The irreducible representations of some covariant algebras are constructed. The generalization of the reflection equation to super case is given and the existence of the quasiclassical limits is pointed out. (orig.)

Lossy compression of quality scores in genomic data.

Science.gov (United States)

Cánovas, Rodrigo; Moffat, Alistair; Turpin, Andrew

2014-08-01

Next-generation sequencing technologies are revolutionizing medicine. Data from sequencing technologies are typically represented as a string of bases, an associated sequence of per-base quality scores and other metadata, and in aggregate can require a large amount of space. The quality scores show how accurate the bases are with respect to the sequencing process, that is, how confident the sequencer is of having called them correctly, and are the largest component in datasets in which they are retained. Previous research has examined how to store sequences of bases effectively; here we add to that knowledge by examining methods for compressing quality scores. The quality values originate in a continuous domain, and so if a fidelity criterion is introduced, it is possible to introduce flexibility in the way these values are represented, allowing lossy compression over the quality score data. We present existing compression options for quality score data, and then introduce two new lossy techniques. Experiments measuring the trade-off between compression ratio and information loss are reported, including quantifying the effect of lossy representations on a downstream application that carries out single nucleotide polymorphism and insert/deletion detection. The new methods are demonstrably superior to other techniques when assessed against the spectrum of possible trade-offs between storage required and fidelity of representation. An implementation of the methods described here is available at https://github.com/rcanovas/libCSAM. rcanovas@student.unimelb.edu.au Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Generalized Magneto-thermo-microstretch Response of a Half-space with Temperature-dependent Properties During Thermal Shock

Directory of Open Access Journals (Sweden)

Qi-lin Xiong

Full Text Available Abstract The generalized magneto-thermoelastic problem of an infinite homogeneous isotropic microstretch half-space with temperature-dependent material properties placed in a transverse magnetic field is investigated in the context of different generalized thermoelastic theories. The upper surface of the half-space is subjected to a zonal time-dependent heat shock. By solving finite element governing equations, the solution to the problem is obtained, from which the transient magneto-thermoelastic responses, including temperature, stresses, displacements, microstretch, microrotation, induced magnetic field and induced electric field are presented graphically. Comparisons are made in the results obtained under different generalized thermoelastic theories to show some unique features of generalized thermoelasticity, and comparisons are made in the results obtained under three forms of temperature dependent material properties (absolute temperature dependent, reference temperature dependent and temperature-independent to show the effects of absolute temperature and reference temperature. Weibull or Log-normal.

Heterotic strings on homogeneous spaces

International Nuclear Information System (INIS)

Israel, D.; Kounnas, C.; Orlando, D.; Petropoulos, P.M.

2005-01-01

We construct heterotic string backgrounds corresponding to families of homogeneous spaces as exact conformal field theories. They contain left cosets of compact groups by their maximal tori supported by NS-NS 2-forms and gauge field fluxes. We give the general formalism and modular-invariant partition functions, then we consider some examples such as SU(2)/U(1)∝S 2 (already described in a previous paper) and the SU(3)/U(1) 2 flag space. As an application we construct new supersymmetric string vacua with magnetic fluxes and a linear dilaton. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Displacement field for an edge dislocation in a layered half-space

Science.gov (United States)

Savage, J.C.

1998-01-01

The displacement field for an edge dislocation in an Earth model consisting of a layer welded to a half-space of different material is found in the form of a Fourier integral following the method given by Weeks et al. [1968]. There are four elementary solutions to be considered: the dislocation is either in the half-space or the layer and the Burgers vector is either parallel or perpendicular to the layer. A general two-dimensional solution for a dip-slip faulting or dike injection (arbitrary dip) can be constructed from a superposition of these elementary solutions. Surface deformations have been calculated for an edge dislocation located at the interface with Burgers vector inclined 0??, 30??, 60??, and 90?? to the interface for the case where the rigidity of the layer is half of that of the half-space and the Poisson ratios are the same. Those displacement fields have been compared to the displacement fields generated by similarly situated edge dislocations in a uniform half-space. The surface displacement field produced by the edge dislocation in the layered half-space is very similar to that produced by an edge dislocation at a different depth in a uniform half-space. In general, a low-modulus (high-modulus) layer causes the half-space equivalent dislocation to appear shallower (deeper) than the actual dislocation in the layered half-space.

Resolution limits of migration and linearized waveform inversion images in a lossy medium

KAUST Repository

Schuster, Gerard T.; Dutta, Gaurav; Li, Jing

2017-01-01

The vertical-and horizontal-resolution limits Delta x(lossy) and Delta z(lossy) of post-stack migration and linearized waveform inversion images are derived for lossy data in the far-field approximation. Unlike the horizontal resolution limit Delta x proportional to lambda z/L in a lossless medium which linearly worsens in depth z, Delta x(lossy) proportional to z(2)/QL worsens quadratically with depth for a medium with small Q values. Here, Q is the quality factor, lambda is the effective wavelength, L is the recording aperture, and loss in the resolution formulae is accounted for by replacing lambda with z/Q. In contrast, the lossy vertical-resolution limit Delta z(lossy) only worsens linearly in depth compared to Delta z proportional to lambda for a lossless medium. For both the causal and acausal Q models, the resolution limits are linearly proportional to 1/Q for small Q. These theoretical predictions are validated with migration images computed from lossy data.

Resolution limits of migration and linearized waveform inversion images in a lossy medium

KAUST Repository

Schuster, Gerard T.

2017-03-10

The vertical-and horizontal-resolution limits Delta x(lossy) and Delta z(lossy) of post-stack migration and linearized waveform inversion images are derived for lossy data in the far-field approximation. Unlike the horizontal resolution limit Delta x proportional to lambda z/L in a lossless medium which linearly worsens in depth z, Delta x(lossy) proportional to z(2)/QL worsens quadratically with depth for a medium with small Q values. Here, Q is the quality factor, lambda is the effective wavelength, L is the recording aperture, and loss in the resolution formulae is accounted for by replacing lambda with z/Q. In contrast, the lossy vertical-resolution limit Delta z(lossy) only worsens linearly in depth compared to Delta z proportional to lambda for a lossless medium. For both the causal and acausal Q models, the resolution limits are linearly proportional to 1/Q for small Q. These theoretical predictions are validated with migration images computed from lossy data.

Conformally compactified homogeneous spaces (Possible Observable Consequences)

International Nuclear Information System (INIS)

Budinich, P.

1995-01-01

Some arguments based on the possible spontaneous violation of the Cosmological Principles (represented by the observed large-scale structures of galaxies), the Cartan-geometry of simple spinors and on the Fock-formulation of hydrogen-atom wave-equation in momentum-space, are presented in favour of the hypothesis that space-time and momentum-space should be both conformally compactified and represented by the two four-dimensional homogeneous spaces of the conformal group, both isomorphic to (S 3 X S 1 )/Z 2 and correlated by conformal inversion. Within this framework, the possible common origin for the S0(4) symmetry underlying the geometrical structure of the Universe, of Kepler orbits and of the H-atom is discussed. On of the consequences of the proposed hypothesis could be that any quantum field theory should be naturally free from both infrared and ultraviolet divergences. But then physical spaces defined as those where physical phenomena may be best described, could be different from those homogeneous spaces. A simple, exactly soluble, toy model, valid for a two-dimensional space-time is presented where the conjecture conformally compactified space-time and momentum-space are both isomorphic to (S 1 X S 1 )/Z 2 , while the physical spaces are two finite lattice which are dual since Fourier transforms, represented by finite, discrete, sums may be well defined on them. Furthermore, a q-deformed SU q (1,1) may be represented on them if q is a root of unity. (author). 22 refs, 3 figs

Half-space albedo problem with modified F{sub N} method for linear and quadratic anisotropic scattering

Energy Technology Data Exchange (ETDEWEB)

Tuereci, R.G. [Kirikkale Univ., Kirikkale (Turkey). Kirikkale Vocational School; Tuereci, D. [Ministry of Education, Ankara (Turkey). 75th year Anatolia High School

2017-05-15

One speed, time independent and homogeneous medium neutron transport equation can be solved with the anisotropic scattering which includes both the linear anisotropic and the quadratic anisotropic scattering properties. Having solved Case's eigenfunctions and the orthogonality relations among these eigenfunctions, some neutron transport problems such as albedo problem can be calculated as numerically by using numerical or semi-analytic methods. In this study the half-space albedo problem is investigated by using the modified F{sub N} method.

Charge accumulation in lossy dielectrics: a review

DEFF Research Database (Denmark)

Rasmussen, Jørgen Knøster; McAllister, Iain Wilson; Crichton, George C

1999-01-01

At present, the phenomenon of charge accumulation in solid dielectrics is under intense experimental study. Using a field theoretical approach, we review the basis for charge accumulation in lossy dielectrics. Thereafter, this macroscopic approach is applied to planar geometries such that the mat......At present, the phenomenon of charge accumulation in solid dielectrics is under intense experimental study. Using a field theoretical approach, we review the basis for charge accumulation in lossy dielectrics. Thereafter, this macroscopic approach is applied to planar geometries...

Analysis of the temporal electric fields in lossy dielectric media

DEFF Research Database (Denmark)

McAllister, Iain Wilson; Crichton, George C

1991-01-01

The time-dependent electric fields associated with lossy dielectric media are examined. The analysis illustrates that, with respect to the basic time constant, these lossy media can take a considerable time to attain a steady-state condition. Time-dependent field enhancement factors are considered......, and inherent surface-charge densities quantified. The calculation of electrostatic forces on a free, lossy dielectric particle is illustrated. An extension to the basic analysis demonstrates that, on reversal of polarity, the resultant tangential field at the interface could play a decisive role...

Homogeneity Property of Besov and Triebel-Lizorkin Spaces

Directory of Open Access Journals (Sweden)

Cornelia Schneider

2012-01-01

Full Text Available We consider the classical Besov and Triebel-Lizorkin spaces defined via differences and prove a homogeneity property for functions with bounded support in the frame of these spaces. As the proof is based on compact embeddings between the studied function spaces, we present also some results on the entropy numbers of these embeddings. Moreover, we derive some applications in terms of pointwise multipliers.

Scattering of three-dimensional plane waves in a self-reinforced half-space lying over a triclinic half-space

Science.gov (United States)

Gupta, Shishir; Pramanik, Abhijit; Smita; Pramanik, Snehamoy

2018-06-01

The phenomenon of plane waves at the intersecting plane of a triclinic half-space and a self-reinforced half-space is discussed with possible applications during wave propagation. Analytical expressions of the phase velocities of reflection and refraction for quasi-compressional and quasi-shear waves under initial stress are discussed carefully. The closest form of amplitude proportions on reflection and refraction factors of three quasi-plane waves are developed mathematically by applying appropriate boundary conditions. Graphics are sketched to exhibit the consequences of initial stress in the three-dimensional plane wave on reflection and refraction coefficients. Some special cases that coincide with the fundamental properties of several layers are designed to express the reflection and refraction coefficients.

Tensor harmonic analysis on homogenous space

International Nuclear Information System (INIS)

Wrobel, G.

1997-01-01

The Hilbert space of tensor functions on a homogenous space with the compact stability group is considered. The functions are decomposed onto a sum of tensor plane waves (defined in the text), components of which are transformed by irreducible representations of the appropriate transformation group. The orthogonality relation and the completeness relation for tensor plane waves are found. The decomposition constitutes a unitary transformation, which allows to obtain the Parseval equality. The Fourier components can be calculated by means of the Fourier transformation, the form of which is given explicitly. (author)

The coherent state on SUq(2) homogeneous space

International Nuclear Information System (INIS)

Aizawa, N; Chakrabarti, R

2009-01-01

The generalized coherent states for quantum groups introduced by Jurco and StovIcek are studied for the simplest example SU q (2) in full detail. It is shown that the normalized SU q (2) coherent states enjoy the property of completeness, and allow a resolution of the unity. This feature is expected to play a key role in the application of these coherent states in physical models. The homogeneous space of SU q (2), i.e. the q-sphere of Podles, is reproduced in complex coordinates by using the coherent states. Differential calculus in the complex form on the homogeneous space is developed. The high spin limit of the SU q (2) coherent states is also discussed.

Lossy/lossless coding of bi-level images

DEFF Research Database (Denmark)

Martins, Bo; Forchhammer, Søren

1997-01-01

Summary form only given. We present improvements to a general type of lossless, lossy, and refinement coding of bi-level images (Martins and Forchhammer, 1996). Loss is introduced by flipping pixels. The pixels are coded using arithmetic coding of conditional probabilities obtained using a template...... as is known from JBIG and proposed in JBIG-2 (Martins and Forchhammer). Our new state-of-the-art results are obtained using the more general free tree instead of a template. Also we introduce multiple refinement template coding. The lossy algorithm is analogous to the greedy `rate...

Abelian gauge theories on homogeneous spaces

International Nuclear Information System (INIS)

Vassilevich, D.V.

1992-07-01

An algebraic technique of separation of gauge modes in Abelian gauge theories on homogeneous spaces is proposed. An effective potential for the Maxwell-Chern-Simons theory on S 3 is calculated. A generalization of the Chern-Simons action is suggested and analysed with the example of SU(3)/U(1) x U(1). (author). 11 refs

Efficient Sparse Signal Transmission over a Lossy Link Using Compressive Sensing

Directory of Open Access Journals (Sweden)

Liantao Wu

2015-08-01

Full Text Available Reliable data transmission over lossy communication link is expensive due to overheads for error protection. For signals that have inherent sparse structures, compressive sensing (CS is applied to facilitate efficient sparse signal transmissions over lossy communication links without data compression or error protection. The natural packet loss in the lossy link is modeled as a random sampling process of the transmitted data, and the original signal will be reconstructed from the lossy transmission results using the CS-based reconstruction method at the receiving end. The impacts of packet lengths on transmission efficiency under different channel conditions have been discussed, and interleaving is incorporated to mitigate the impact of burst data loss. Extensive simulations and experiments have been conducted and compared to the traditional automatic repeat request (ARQ interpolation technique, and very favorable results have been observed in terms of both accuracy of the reconstructed signals and the transmission energy consumption. Furthermore, the packet length effect provides useful insights for using compressed sensing for efficient sparse signal transmission via lossy links.

StirMark Benchmark: audio watermarking attacks based on lossy compression

Science.gov (United States)

Steinebach, Martin; Lang, Andreas; Dittmann, Jana

2002-04-01

StirMark Benchmark is a well-known evaluation tool for watermarking robustness. Additional attacks are added to it continuously. To enable application based evaluation, in our paper we address attacks against audio watermarks based on lossy audio compression algorithms to be included in the test environment. We discuss the effect of different lossy compression algorithms like MPEG-2 audio Layer 3, Ogg or VQF on a selection of audio test data. Our focus is on changes regarding the basic characteristics of the audio data like spectrum or average power and on removal of embedded watermarks. Furthermore we compare results of different watermarking algorithms and show that lossy compression is still a challenge for most of them. There are two strategies for adding evaluation of robustness against lossy compression to StirMark Benchmark: (a) use of existing free compression algorithms (b) implementation of a generic lossy compression simulation. We discuss how such a model can be implemented based on the results of our tests. This method is less complex, as no real psycho acoustic model has to be applied. Our model can be used for audio watermarking evaluation of numerous application fields. As an example, we describe its importance for e-commerce applications with watermarking security.

On the theory of inelastic scattering of slow electrons by surface excitations: 1. Half-space formalism

International Nuclear Information System (INIS)

Nkoma, J.S.

1982-08-01

A quantum-mechanical theory for the inelastic scattering of slow electrons (ISSE) by surface excitations is developed within the half-space model. The process of transmission of incident electrons into the crystal is described by the homogeneous Schroedinger equation, while the scattering process inside the crystal is described by an inhomogeneous Schroedinger equation. The scattering cross-section for ISSE by surface excitations is derived and is found to be small since it is dependent on an inverse sum of wavevectors which is large. It is also dependent on the fluctuations in the scattering potential. (author)

Enhanced inertia from lossy effective fluids using multi-scale sonic crystals

Directory of Open Access Journals (Sweden)

Matthew D. Guild

2014-12-01

Full Text Available In this work, a recent theoretically predicted phenomenon of enhanced permittivity with electromagnetic waves using lossy materials is investigated for the analogous case of mass density and acoustic waves, which represents inertial enhancement. Starting from fundamental relationships for the homogenized quasi-static effective density of a fluid host with fluid inclusions, theoretical expressions are developed for the conditions on the real and imaginary parts of the constitutive fluids to have inertial enhancement, which are verified with numerical simulations. Realizable structures are designed to demonstrate this phenomenon using multi-scale sonic crystals, which are fabricated using a 3D printer and tested in an acoustic impedance tube, yielding good agreement with the theoretical predictions and demonstrating enhanced inertia.

Numerical modelling of complex resistivity effects on a homogeneous half-space at low frequencies

DEFF Research Database (Denmark)

Ingeman-Nielsen, Thomas; Baumgartner, François

2006-01-01

for environmental applications and thanks to technological progress, the use of wide band frequency equipment seems promising, and it is expected to shed light on the different results among the published solutions to the electromagnetic (EM) coupling problem. We review the theory of EM coupling over a homogeneous...

Static deformation of two welded monoclinic elastic half-spaces due ...

Indian Academy of Sciences (India)

M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

Static deformation of two monoclinic elastic half-spaces in welded contact due to a long inclined strike-slip fault situated in one of the half-spaces is studied analytically and numerically. Closed- form algebraic expressions for the displacement at any point of the medium are obtained. The variation of the displacement at the ...

Non-Homogenous Moral Space (from Bentham toSen

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Piotr (Peter Boltuc

2013-12-01

Full Text Available The notion of moral space covers all thin (universal and thick (particular characteristics that may plausibly be seen as morally relevant. In this paper, I investigate certain properties of moral space so defined. These properties are not easily visible if we analyze moral characteristics individually, but become clear once we consider them collectively. In particular, following Amartya Sen, I claim that the value of moral properties is, in part, a function of positional characteristics. I call this notion the non-homogeneity of moral space.

Regional homogeneity of electoral space: comparative analysis (on the material of 100 national cases

Directory of Open Access Journals (Sweden)

A. O. Avksentiev

2015-12-01

Full Text Available In the article the author examines dependence on electoral behavior from territorial belonging. «Regional homogeneity» and «electoral space» categories are conceptualized. It is argued, that such regional homogeneity is a characteristic of electoral space and can be quantified. Quantitative measurement of government regional homogeneity has direct connection with risk of separatism, civil conflicts, or legitimacy crisis on deviant territories. It is proposed the formulae for evaluation of regional homogeneity quantitative method which has been based on statistics analysis instrument, especially, variation coefficient. Possible directions of study with the use of this index according to individual political subjects and the whole political space (state, region, electoral district are defined. Calculation of appropriate indexes for Ukrainian electoral space (return of 1991­2015 elections and 100 other national cases. The dynamics of Ukraine regional homogeneity on the material of 1991­2015 electoral statistics is analyzed.

Recent advances in lossy compression of scientific floating-point data

Science.gov (United States)

Lindstrom, P.

2017-12-01

With a continuing exponential trend in supercomputer performance, ever larger data sets are being generated through numerical simulation. Bandwidth and storage capacity are, however, not keeping pace with this increase in data size, causing significant data movement bottlenecks in simulation codes and substantial monetary costs associated with archiving vast volumes of data. Worse yet, ever smaller fractions of data generated can be stored for further analysis, where scientists frequently rely on decimating or averaging large data sets in time and/or space. One way to mitigate these problems is to employ data compression to reduce data volumes. However, lossless compression of floating-point data can achieve only very modest size reductions on the order of 10-50%. We present ZFP and FPZIP, two state-of-the-art lossy compressors for structured floating-point data that routinely achieve one to two orders of magnitude reduction with little to no impact on the accuracy of visualization and quantitative data analysis. We provide examples of the use of such lossy compressors in climate and seismic modeling applications to effectively accelerate I/O and reduce storage requirements. We further discuss how the design decisions behind these and other compressors impact error distributions and other statistical and differential properties, including derived quantities of interest relevant to each science application.

A lossy graph model for delay reduction in generalized instantly decodable network coding

KAUST Repository

Douik, Ahmed S.

2014-06-01

The problem of minimizing the decoding delay in Generalized instantly decodable network coding (G-IDNC) for both perfect and lossy feedback scenarios is formulated as a maximum weight clique problem over the G-IDNC graph in. In this letter, we introduce a new lossy G-IDNC graph (LG-IDNC) model to further minimize the decoding delay in lossy feedback scenarios. Whereas the G-IDNC graph represents only doubtless combinable packets, the LG-IDNC graph represents also uncertain packet combinations, arising from lossy feedback events, when the expected decoding delay of XORing them among themselves or with other certain packets is lower than that expected when sending these packets separately. We compare the decoding delay performance of LG-IDNC and G-IDNC graphs through extensive simulations. Numerical results show that our new LG-IDNC graph formulation outperforms the G-IDNC graph formulation in all lossy feedback situations and achieves significant improvement in the decoding delay especially when the feedback erasure probability is higher than the packet erasure probability. © 2012 IEEE.

Accounting for Antenna in Half-Space Fresnel Coefficient Estimation

Directory of Open Access Journals (Sweden)

A. D'Alterio

2012-01-01

Full Text Available The problem of retrieving the Fresnel reflection coefficients of a half-space medium starting from measurements collected under a reflection mode multistatic configuration is dealt with. According to our previous results, reflection coefficient estimation is cast as the inversion of linear operator. However, here, we take a step ahead towards more realistic scenarios as the role of antennas (both transmitting and receiving is embodied in the estimation procedure. Numerical results are presented to show the effectiveness of the method for different types of half-space media.

High thermal conductivity lossy dielectric using co-densified multilayer configuration

Science.gov (United States)

Tiegs, Terry N.; Kiggans, Jr., James O.

2003-06-17

Systems and methods are described for loss dielectrics. A method of manufacturing a lossy dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer and then densifying together. The systems and methods provide advantages because the lossy dielectrics are less costly and more environmentally friendly than the available alternatives.

CFOA-Based Lossless and Lossy Inductance Simulators

Directory of Open Access Journals (Sweden)

F. Kaçar

2011-09-01

Full Text Available Inductance simulator is a useful component in the circuit synthesis theory especially for analog signal processing applications such as filter, chaotic oscillator design, analog phase shifters and cancellation of parasitic element. In this study, new four inductance simulator topologies employing a single current feedback operational amplifier are presented. The presented topologies require few passive components. The first topology is intended for negative inductance simulation, the second topology is for lossy series inductance, the third one is for lossy parallel inductance and the fourth topology is for negative parallel (-R (-L (-C simulation. The performance of the proposed CFOA based inductance simulators is demonstrated on both a second-order low-pass filter and inductance cancellation circuit. PSPICE simulations are given to verify the theoretical analysis.

Rayleigh Waves in a Rotating Orthotropic Micropolar Elastic Solid Half-Space

Directory of Open Access Journals (Sweden)

Baljeet Singh

2013-01-01

Full Text Available A problem on Rayleigh wave in a rotating half-space of an orthotropic micropolar material is considered. The governing equations are solved for surface wave solutions in the half space of the material. These solutions satisfy the boundary conditions at free surface of the half-space to obtain the frequency equation of the Rayleigh wave. For numerical purpose, the frequency equation is approximated. The nondimensional speed of Rayleigh wave is computed and shown graphically versus nondimensional frequency and rotation-frequency ratio for both orthotropic micropolar elastic and isotropic micropolar elastic cases. The numerical results show the effects of rotation, orthotropy, and nondimensional frequency on the nondimensional speed of the Rayleigh wave.

Ignition of a combustible half space

Science.gov (United States)

Olmstead, W. E.

1983-01-01

A half space of combustible material is subjected to an arbitrary energy flux at the boundary where convection heat loss is also allowed. An asymptotic analysis of the temperature growth reveals two conditions necessary for ignition to occur. Cases of both large and order unity Lewis number are shown to lead to a nonlinear integral equation governing the thermal runaway. Some global and asymptotic properties of the integral equation are obtained.

Electrostatic images for underwater anisotropic conductive half spaces

International Nuclear Information System (INIS)

Flykt, M.; Lindell, I.; Eloranta, E.

1998-01-01

A static image principle makes it possible to derive analytical solutions to some basic geometries for DC fields. The underwater environment is especially difficult both from the theoretical and practical point of view. However, there are increasing demands that also the underwater geological formations should be studied in detail. The traditional image of a point source lies at the mirror point of the original. When anisotropic media is involved, however, the image location can change and the image source may be a continues, sector-like distribution. In this paper some theoretical considerations are carried out in the case where the lower half space can have a very general anisotropy in terms of electrical conductivity, while the upper half space is assumed isotropic. The reflection potential field is calculated for different values of electrical conductivity. (orig.)

Development of the town Viljandi in light of the studies at Lossi street / Eero Heinloo

Index Scriptorium Estoniae

Heinloo, Eero

2015-01-01

Uuringud näitasid, et varaseim püsiasustusele viitav ladestus on ulatunud Lossi ja Kauba tänavate ristist kuni Lossi tn 3 ja 4 hoonete vahelise alani. Hetkeseisus ei saa püsiasustuse algust dateerida varasemaks kui 13. sajandi keskpaik. Lossi tänava kujunemise võib dateerida 1270. või 1280. aastatesse. Hiljemalt 14. sajandi II veerandil on tänava puitsillutis asendatud munakivisillutisega.

Notes on a class of homogeneous space-times

International Nuclear Information System (INIS)

Calvao, M.O.; Reboucas, M.J.; Teixeira, A.F.F.; Silva Junior, W.M.

1987-01-01

The breakdown of causality in homogeneous Goedel-type space-time manifolds is examined. An extension of Reboucas-Tiomno (RT) study is made. The existence of noncausal curves is also investigated under two different conditions on the energy-momentum tensor. An integral representation of the infinitesimal generators of isometries is obtained extending previous works on the RT geometry. (Author) [pt

The extensions of space-time. Physics in the 8-dimensional homogeneous space D = SU(2,2)/K

International Nuclear Information System (INIS)

Barut, A.O.

1993-07-01

The Minkowski space-time is only a boundary of a bigger homogeneous space of the conformal group. The conformal group is the symmetry group of our most fundamental massless wave equations. These extended groups and spaces have many remarkable properties and physical implications. (author). 36 refs

Solving for the capacity of a noisy lossy bosonic channel via the master equation

International Nuclear Information System (INIS)

Qin Tao; Zhao Meisheng; Zhang Yongde

2006-01-01

We discuss the noisy lossy bosonic channel by exploiting master equations. The capacity of the noisy lossy bosonic channel and the criterion for the optimal capacities are derived. Consequently, we verify that master equations can be a tool to study bosonic channels

Rembrandt Kadrioru lossis / Jüri Hain

Index Scriptorium Estoniae

Hain, Jüri, 1941-

2000-01-01

Kadrioru lossi kuppelsaali tundmatu meistri laemaali maalimise ajalugu. Maali aluseks on Rembrandti maal "Diana suplus". Laemaal on maalitud Magdalena de Passe (1600-1638) vasegravüüri põhjal, mis on tehtud Rembrandti maalist. Rembrandt on lähtunud Antonio Tempesta (1555-1630) kahest gravüürist, viimane on lähtunud Otto van Veeni (1556-1629) maalist

Propagation of plane waves at the interface of an elastic solid half-space and a microstretch thermoelastic diffusion solid half-space

Directory of Open Access Journals (Sweden)

Rajneesh Kumar

Full Text Available The problem of reflection and refraction phenomenon due to plane waves incident obliquely at a plane interface between uniform elastic solid half-space and microstretch thermoelastic diffusion solid half-space has been studied. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence, frequency of incident wave and are influenced by the microstretch thermoelastic diffusion properties of the media. The expressions of amplitude ratios and energy ratios are obtained in closed form. The energy ratios have been computed numerically for a particular model. The variations of energy ratios with angle of incidence are shown for thermoelastic diffusion media in the context of Lord-Shulman (L-S (1967 and Green-Lindsay (G-L (1972 theories. The conservation of energy at the interface is verified. Some particular cases are also deduced from the present investigation.

On the existence of conformal Killing vectors for ST-homogeneous Godel type space-times

Energy Technology Data Exchange (ETDEWEB)

Parra, Y.; Patino, A.; Percoco, U. [Laboratorio de Fisica Teorica, Facultad de Ciencias Universidad de los Andes, Merida 5101 (Venezuela); Tsamparlis, M. [seccion de Astronomia-Astrofisica-Mecanica, Universidad de Atenas, Atenas 157 83 (Greece)

2006-07-01

Tsamparlis with another authors have developed a systematic method for computing of the conformal algebra of 1+3 space-times. The proper CKV's are found in terms of gradient CKVs of the 3-space. In this paper we apply Tsamparlis' results to the study CKVs of the Godel ST-Homogeneous type spacetimes. We find that the only space-time admitting proper CKV's is the ST-Homogeneous Godel type with m{sup 2} = 4{omega}{sup 2} (RT). (Author)

An Evaluation Framework for Lossy Compression of Genome Sequencing Quality Values

OpenAIRE

Alberti, Claudio; Daniels, Noah; Hernaez, Mikel; Voges, Jan; Goldfeder, Rachel L.; Hernandez-Lopez, Ana A.; Mattavelli, Marco; Berger, Bonnie

2016-01-01

This paper provides the specification and an initial validation of an evaluation framework for the comparison of lossy compressors of genome sequencing quality values. The goal is to define reference data, test sets, tools and metrics that shall be used to evaluate the impact of lossy compression of quality values on human genome variant calling. The functionality of the framework is validated referring to two state-of-the-art genomic compressors. This work has been spurred by the current act...

Normal Mode Analysis to a Poroelastic Half-Space Problem under Generalized Thermoelasticity

Directory of Open Access Journals (Sweden)

Chunbao Xiong

Full Text Available Abstract The thermo-hydro-mechanical problems associated with a poroelastic half-space soil medium with variable properties under generalized thermoelasticity theory were investigated in this study. By remaining faithful to Biot’s theory of dynamic poroelasticity, we idealized the foundation material as a uniform, fully saturated, poroelastic half-space medium. We first subjected this medium to time harmonic loads consisting of normal or thermal loads, then investigated the differences between the coupled thermohydro-mechanical dynamic models and the thermo-elastic dynamic models. We used normal mode analysis to solve the resulting non-dimensional coupled equations, then investigated the effects that non-dimensional vertical displacement, excess pore water pressure, vertical stress, and temperature distribution exerted on the poroelastic half-space medium and represented them graphically.

Optimal design of lossy bandgap structures

DEFF Research Database (Denmark)

Jensen, Jakob Søndergaard

2004-01-01

The method of topology optimization is used to design structures for wave propagation with one lossy material component. Optimized designs for scalar elastic waves are presented for mininimum wave transmission as well as for maximum wave energy dissipation. The structures that are obtained...... are of the 1D or 2D bandgap type depending on the objective and the material parameters....

Quantum optics of lossy asymmetric beam splitters

NARCIS (Netherlands)

Uppu, Ravitej; Wolterink, Tom; Tentrup, Tristan Bernhard Horst; Pinkse, Pepijn Willemszoon Harry

2016-01-01

We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2×2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering

Lossy compression for Animated Web Visualisation

Science.gov (United States)

Prudden, R.; Tomlinson, J.; Robinson, N.; Arribas, A.

2017-12-01

This talk will discuss an technique for lossy data compression specialised for web animation. We set ourselves the challenge of visualising a full forecast weather field as an animated 3D web page visualisation. This data is richly spatiotemporal, however it is routinely communicated to the public as a 2D map, and scientists are largely limited to visualising data via static 2D maps or 1D scatter plots. We wanted to present Met Office weather forecasts in a way that represents all the generated data. Our approach was to repurpose the technology used to stream high definition videos. This enabled us to achieve high rates of compression, while being compatible with both web browsers and GPU processing. Since lossy compression necessarily involves discarding information, evaluating the results is an important and difficult problem. This is essentially a problem of forecast verification. The difficulty lies in deciding what it means for two weather fields to be "similar", as simple definitions such as mean squared error often lead to undesirable results. In the second part of the talk, I will briefly discuss some ideas for alternative measures of similarity.

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

Directory of Open Access Journals (Sweden)

Vladimir P. Radchenko

2015-09-01

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

Steady sliding frictional contact problem for a 2d elastic half-space with a discontinuous friction coefficient and related stress singularities

Science.gov (United States)

Ballard, Patrick

2016-12-01

The steady sliding frictional contact problem between a moving rigid indentor of arbitrary shape and an isotropic homogeneous elastic half-space in plane strain is extensively analysed. The case where the friction coefficient is a step function (with respect to the space variable), that is, where there are jumps in the friction coefficient, is considered. The problem is put under the form of a variational inequality which is proved to always have a solution which, in addition, is unique in some cases. The solutions exhibit different kinds of universal singularities that are explicitly given. In particular, it is shown that the nature of the universal stress singularity at a jump of the friction coefficient is different depending on the sign of the jump.

Foundation plate on the elastic half-space, deterministic and probabilistic approach

Directory of Open Access Journals (Sweden)

Tvrdá Katarína

2017-01-01

Full Text Available Interaction between the foundation plate and subgrade can be described by different mathematical - physical model. Elastic foundation can be modelled by different types of models, e.g. one-parametric model, two-parametric model and a comprehensive model - Boussinesque (elastic half-space had been used. The article deals with deterministic and probabilistic analysis of deflection of the foundation plate on the elastic half-space. Contact between the foundation plate and subsoil was modelled using contact elements node-node. At the end the obtained results are presented.

Task-oriented lossy compression of magnetic resonance images

Science.gov (United States)

Anderson, Mark C.; Atkins, M. Stella; Vaisey, Jacques

1996-04-01

A new task-oriented image quality metric is used to quantify the effects of distortion introduced into magnetic resonance images by lossy compression. This metric measures the similarity between a radiologist's manual segmentation of pathological features in the original images and the automated segmentations performed on the original and compressed images. The images are compressed using a general wavelet-based lossy image compression technique, embedded zerotree coding, and segmented using a three-dimensional stochastic model-based tissue segmentation algorithm. The performance of the compression system is then enhanced by compressing different regions of the image volume at different bit rates, guided by prior knowledge about the location of important anatomical regions in the image. Application of the new system to magnetic resonance images is shown to produce compression results superior to the conventional methods, both subjectively and with respect to the segmentation similarity metric.

Privacy of a lossy bosonic memory channel

Energy Technology Data Exchange (ETDEWEB)

Ruggeri, Giovanna [Dipartimento di Fisica, Universita di Lecce, I-73100 Lecce (Italy)]. E-mail: ruggeri@le.infn.it; Mancini, Stefano [Dipartimento di Fisica, Universita di Camerino, I-62032 Camerino (Italy)]. E-mail: stefano.mancini@unicam.it

2007-03-12

We study the security of the information transmission between two honest parties realized through a lossy bosonic memory channel when losses are captured by a dishonest party. We then show that entangled inputs can enhance the private information of such a channel, which however does never overcome that of unentangled inputs in absence of memory.

Privacy of a lossy bosonic memory channel

International Nuclear Information System (INIS)

Ruggeri, Giovanna; Mancini, Stefano

2007-01-01

We study the security of the information transmission between two honest parties realized through a lossy bosonic memory channel when losses are captured by a dishonest party. We then show that entangled inputs can enhance the private information of such a channel, which however does never overcome that of unentangled inputs in absence of memory

Neutron guide geometries for homogeneous phase space volume transformation

Energy Technology Data Exchange (ETDEWEB)

Stüßer, N., E-mail: stuesser@helmholtz-berlin.de; Bartkowiak, M.; Hofmann, T.

2014-06-01

We extend geometries for recently developed optical guide systems that perform homogeneous phase space volume transformations on neutron beams. These modules allow rotating beam directions and can simultaneously compress or expand the beam cross-section. Guide systems combining these modules offer the possibility to optimize ballistic guides with and without direct view on the source and beam splitters. All systems are designed for monochromatic beams with a given divergence. The case of multispectral beams with wavelength-dependent divergence distributions is addressed as well. - Highlights: • Form invariant volume transformation in phase space. • Geometrical approach. • Ballistic guide, beam splitter, beam bender.

Neutron guide geometries for homogeneous phase space volume transformation

International Nuclear Information System (INIS)

Stüßer, N.; Bartkowiak, M.; Hofmann, T.

2014-01-01

We extend geometries for recently developed optical guide systems that perform homogeneous phase space volume transformations on neutron beams. These modules allow rotating beam directions and can simultaneously compress or expand the beam cross-section. Guide systems combining these modules offer the possibility to optimize ballistic guides with and without direct view on the source and beam splitters. All systems are designed for monochromatic beams with a given divergence. The case of multispectral beams with wavelength-dependent divergence distributions is addressed as well. - Highlights: • Form invariant volume transformation in phase space. • Geometrical approach. • Ballistic guide, beam splitter, beam bender

Partially blind instantly decodable network codes for lossy feedback environment

KAUST Repository

Sorour, Sameh

2014-09-01

In this paper, we study the multicast completion and decoding delay minimization problems for instantly decodable network coding (IDNC) in the case of lossy feedback. When feedback loss events occur, the sender falls into uncertainties about packet reception at the different receivers, which forces it to perform partially blind selections of packet combinations in subsequent transmissions. To determine efficient selection policies that reduce the completion and decoding delays of IDNC in such an environment, we first extend the perfect feedback formulation in our previous works to the lossy feedback environment, by incorporating the uncertainties resulting from unheard feedback events in these formulations. For the completion delay problem, we use this formulation to identify the maximum likelihood state of the network in events of unheard feedback and employ it to design a partially blind graph update extension to the multicast IDNC algorithm in our earlier work. For the decoding delay problem, we derive an expression for the expected decoding delay increment for any arbitrary transmission. This expression is then used to find the optimal policy that reduces the decoding delay in such lossy feedback environment. Results show that our proposed solutions both outperform previously proposed approaches and achieve tolerable degradation even at relatively high feedback loss rates.

Lossy/Lossless Floating/Grounded Inductance Simulation Using One DDCC

Directory of Open Access Journals (Sweden)

M. A. Ibrahim

2012-04-01

Full Text Available In this work, we present new topologies for realizing one lossless grounded inductor and two floating, one lossless and one lossy, inductors employing a single differential difference current conveyor (DDCC and a minimum number of passive components, two resistors, and one grounded capacitor. The floating inductors are based on ordinary dual-output differential difference current conveyor (DO-DDCC while the grounded lossless inductor is based one a modified dual-output differential difference current conveyor (MDO-DDCC. The proposed lossless floating inductor is obtained from the lossy one by employing a negative impedance converter (NIC. The non-ideality effects of the active element on the simulated inductors are investigated. To demonstrate the performance of the proposed grounded inductance simulator as an example, it is used to construct a parallel resonant circuit. SPICE simulation results are given to confirm the theoretical analysis.

Projective embeddings of homogeneous spaces with small boundary

International Nuclear Information System (INIS)

Arzhantsev, Ivan V

2009-01-01

We study open equivariant projective embeddings of homogeneous spaces such that the complement of the open orbit has codimension at least 2. We establish a criterion for the existence of such an embedding, prove that the set of isomorphism classes of such embeddings is finite, and give a construction of the embeddings in terms of Geometric Invariant Theory. A generalization of Cox's construction and the theory of bunched rings enable us to describe in combinatorial terms the basic geometric properties of embeddings with small boundary

An Evaluation Framework for Lossy Compression of Genome Sequencing Quality Values.

Science.gov (United States)

Alberti, Claudio; Daniels, Noah; Hernaez, Mikel; Voges, Jan; Goldfeder, Rachel L; Hernandez-Lopez, Ana A; Mattavelli, Marco; Berger, Bonnie

2016-01-01

This paper provides the specification and an initial validation of an evaluation framework for the comparison of lossy compressors of genome sequencing quality values. The goal is to define reference data, test sets, tools and metrics that shall be used to evaluate the impact of lossy compression of quality values on human genome variant calling. The functionality of the framework is validated referring to two state-of-the-art genomic compressors. This work has been spurred by the current activity within the ISO/IEC SC29/WG11 technical committee (a.k.a. MPEG), which is investigating the possibility of starting a standardization activity for genomic information representation.

Dyakonov surface waves in lossy metamaterials

OpenAIRE

Sorní Laserna, Josep; Naserpour, Mahin; Zapata Rodríguez, Carlos Javier; Miret Marí, Juan José

2015-01-01

We analyze the existence of localized waves in the vicinities of the interface between two dielectrics, provided one of them is uniaxial and lossy. We found two families of surface waves, one of them approaching the well-known Dyakonov surface waves (DSWs). In addition, a new family of wave fields exists which are tightly bound to the interface. Although its appearance is clearly associated with the dissipative character of the anisotropic material, the characteristic propagation length of su...

Deformation of a flexible disk bonded to an elastic half space-application to the lung.

Science.gov (United States)

Lai-Fook, S J; Hajji, M A; Wilson, T A

1980-08-01

An analysis is presented of the deformation of a homogeneous, isotropic, elastic half space subjected to a constant radial strain in a circular area on the boundary. Explicit analytic expressions for the normal and radial displacements and the shear stress on the boundary are used to interpret experiments performed on inflated pig lungs. The boundary strain was induced by inflating or deflating the lung after bonding a flexible disk to the lung surface. The prediction that the surface bulges outward for positive boundary strain and inward for negative strain was observed in the experiments. Poisson's ratio at two transpulmonary pressures was measured, by use of the normal displacement equation evaluated at the surface. A direct estimate of Poisson's ratio was possible because the normal displacement of the surface depended uniquely on the compressibility of the material. Qualitative comparisons between theory and experiment support the use of continuum analyses in evaluating the behavior of the lung parenchyma when subjected to small local distortions.

An introduction to Lie groups and the geometry of homogeneous spaces

CERN Document Server

Arvanitoyeorgos, Andreas

2003-01-01

It is remarkable that so much about Lie groups could be packed into this small book. But after reading it, students will be well-prepared to continue with more advanced, graduate-level topics in differential geometry or the theory of Lie groups. The theory of Lie groups involves many areas of mathematics. In this book, Arvanitoyeorgos outlines enough of the prerequisites to get the reader started. He then chooses a path through this rich and diverse theory that aims for an understanding of the geometry of Lie groups and homogeneous spaces. In this way, he avoids the extra detail needed for a thorough discussion of other topics. Lie groups and homogeneous spaces are especially useful to study in geometry, as they provide excellent examples where quantities (such as curvature) are easier to compute. A good understanding of them provides lasting intuition, especially in differential geometry. The book is suitable for advanced undergraduates, graduate students, and research mathematicians interested in differenti...

Security of modified Ping-Pong protocol in noisy and lossy channel.

Science.gov (United States)

Han, Yun-Guang; Yin, Zhen-Qiang; Li, Hong-Wei; Chen, Wei; Wang, Shuang; Guo, Guang-Can; Han, Zheng-Fu

2014-05-12

The "Ping-Pong" (PP) protocol is a two-way quantum key protocol based on entanglement. In this protocol, Bob prepares one maximally entangled pair of qubits, and sends one qubit to Alice. Then, Alice performs some necessary operations on this qubit and sends it back to Bob. Although this protocol was proposed in 2002, its security in the noisy and lossy channel has not been proven. In this report, we add a simple and experimentally feasible modification to the original PP protocol, and prove the security of this modified PP protocol against collective attacks when the noisy and lossy channel is taken into account. Simulation results show that our protocol is practical.

Spectral Distortion in Lossy Compression of Hyperspectral Data

Directory of Open Access Journals (Sweden)

Bruno Aiazzi

2012-01-01

Full Text Available Distortion allocation varying with wavelength in lossy compression of hyperspectral imagery is investigated, with the aim of minimizing the spectral distortion between original and decompressed data. The absolute angular error, or spectral angle mapper (SAM, is used to quantify spectral distortion, while radiometric distortions are measured by maximum absolute deviation (MAD for near-lossless methods, for example, differential pulse code modulation (DPCM, or mean-squared error (MSE for lossy methods, for example, spectral decorrelation followed by JPEG 2000. Two strategies of interband distortion allocation are compared: given a target average bit rate, distortion may be set to be constant with wavelength. Otherwise, it may be allocated proportionally to the noise level of each band, according to the virtually lossless protocol. Comparisons with the uncompressed originals show that the average SAM of radiance spectra is minimized by constant distortion allocation to radiance data. However, variable distortion allocation according to the virtually lossless protocol yields significantly lower SAM in case of reflectance spectra obtained from compressed radiance data, if compared with the constant distortion allocation at the same compression ratio.

Classification of compact homogeneous spaces with invariant G(2)-structures

Czech Academy of Sciences Publication Activity Database

Le, Hong-Van; Munir, M.

2012-01-01

Roč. 12, č. 2 (2012), s. 303-328 ISSN 1615-715X R&D Projects: GA AV ČR IAA100190701 Institutional support: RVO:67985840 Keywords : compact homogeneous space * G(2)-structure Subject RIV: BA - General Mathematics Impact factor: 0.371, year: 2012 http://www.degruyter.com/view/j/advg.2012.12.issue-2/advgeom.2011.054/advgeom.2011.054. xml

Fractional type Marcinkiewicz integrals over non-homogeneous metric measure spaces

Directory of Open Access Journals (Sweden)

Guanghui Lu

2016-10-01

Full Text Available Abstract The main goal of the paper is to establish the boundedness of the fractional type Marcinkiewicz integral M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ on non-homogeneous metric measure space which includes the upper doubling and the geometrically doubling conditions. Under the assumption that the kernel satisfies a certain Hörmander-type condition, the authors prove that M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ is bounded from Lebesgue space L 1 ( μ $L^{1}(\\mu$ into the weak Lebesgue space L 1 , ∞ ( μ $L^{1,\\infty}(\\mu$ , from the Lebesgue space L ∞ ( μ $L^{\\infty}(\\mu$ into the space RBLO ( μ $\\operatorname{RBLO}(\\mu$ , and from the atomic Hardy space H 1 ( μ $H^{1}(\\mu$ into the Lebesgue space L 1 ( μ $L^{1}(\\mu$ . Moreover, the authors also get a corollary, that is, M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ is bounded on L p ( μ $L^{p}(\\mu$ with 1 < p < ∞ $1< p<\\infty$ .

Space-dependent step features: Transient breakdown of slow-roll, homogeneity, and isotropy during inflation

International Nuclear Information System (INIS)

Lerner, Rose N.; McDonald, John

2009-01-01

A step feature in the inflaton potential can model a transient breakdown of slow-roll inflation. Here we generalize the step feature to include space-dependence, allowing it also to model a breakdown of homogeneity and isotropy. The space-dependent inflaton potential generates a classical curvature perturbation mode characterized by the wave number of the step inhomogeneity. For inhomogeneities small compared with the horizon at the step, space-dependence has a small effect on the curvature perturbation. Therefore, the smoothly oscillating quantum power spectrum predicted by the homogeneous step is robust with respect to subhorizon space-dependence. For inhomogeneities equal to or greater than the horizon at the step, the space-dependent classical mode can dominate, producing a curvature perturbation in which modes of wave number determined by the step inhomogeneity are superimposed on the oscillating power spectrum. Generation of a space-dependent step feature may therefore provide a mechanism to introduce primordial anisotropy into the curvature perturbation. Space-dependence also modifies the quantum fluctuations, in particular, via resonancelike features coming from mode coupling to amplified superhorizon modes. However, these effects are small relative to the classical modes.

The Visual Uncertainty Paradigm for Controlling Screen-Space Information in Visualization

Science.gov (United States)

Dasgupta, Aritra

2012-01-01

The information visualization pipeline serves as a lossy communication channel for presentation of data on a screen-space of limited resolution. The lossy communication is not just a machine-only phenomenon due to information loss caused by translation of data, but also a reflection of the degree to which the human user can comprehend visual…

Partially blind instantly decodable network codes for lossy feedback environment

KAUST Repository

Sorour, Sameh; Douik, Ahmed S.; Valaee, Shahrokh; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2014-01-01

an expression for the expected decoding delay increment for any arbitrary transmission. This expression is then used to find the optimal policy that reduces the decoding delay in such lossy feedback environment. Results show that our proposed solutions both

Lossy compression of TPC data and trajectory tracking efficiency for the ALICE experiment

CERN Document Server

Nicolaucig, A; Mattavelli, M

2003-01-01

In this paper a quasi-lossless algorithm for the on-line compression of the data generated by the Time Projection Chamber (TPC) detector of the ALICE experiment at CERN is described. The algorithm is based on a lossy source code modeling technique, i.e. it is based on a source model which is lossy if samples of the TPC signal are considered one by one; conversely, the source model is lossless or quasi-lossless if some physical quantities that are of main interest for the experiment are considered. These quantities are the area and the location of the center of mass of each TPC signal pulse, representing the pulse charge and the time localization of the pulse. So as to evaluate the consequences of the error introduced by the lossy compression process, the results of the trajectory tracking algorithms that process data off-line after the experiment are analyzed, in particular, versus their sensibility to the noise introduced by the compression. Two different versions of these off- line algorithms are described,...

Edge-Based Image Compression with Homogeneous Diffusion

Science.gov (United States)

Mainberger, Markus; Weickert, Joachim

It is well-known that edges contain semantically important image information. In this paper we present a lossy compression method for cartoon-like images that exploits information at image edges. These edges are extracted with the Marr-Hildreth operator followed by hysteresis thresholding. Their locations are stored in a lossless way using JBIG. Moreover, we encode the grey or colour values at both sides of each edge by applying quantisation, subsampling and PAQ coding. In the decoding step, information outside these encoded data is recovered by solving the Laplace equation, i.e. we inpaint with the steady state of a homogeneous diffusion process. Our experiments show that the suggested method outperforms the widely-used JPEG standard and can even beat the advanced JPEG2000 standard for cartoon-like images.

Possibility of perfect concealment by lossy conventional and lossy metamaterial cylindrical invisibility cloaks

Science.gov (United States)

Dehbashi, Reza; Shahabadi, Mahmoud

2013-12-01

The commonly used coordinate transformation for cylindrical cloaks is generalized. This transformation is utilized to determine an anisotropic inhomogeneous diagonal material tensors of a shell type cloak for various material types, i.e., double-positive (DPS: ɛ, μ > 0), double-negative (DNG: ɛ, μ cloaking for various material types, a rigorous analysis is performed. It is shown that perfect cloaking will be achieved for same type material for the cloak and its surrounding medium. Moreover, material losses are included in the analysis to demonstrate that perfect cloaking for lossy materials can be achieved for identical loss tangent of the cloak and its surrounding material. Sensitivity of the cloaking performance to losses for different material types is also investigated. The obtained analytical results are verified using a Finite-Element computational analysis.

Quantization of the Poisson SU(2) and its Poisson homogeneous space - the 2-sphere

International Nuclear Information System (INIS)

Sheu, A.J.L.

1991-01-01

We show that deformation quantizations of the Poisson structures on the Poisson Lie group SU(2) and its homogeneous space, the 2-sphere, are compatible with Woronowicz's deformation quantization of SU(2)'s group structure and Podles' deformation quantization of 2-sphere's homogeneous structure, respectively. So in a certain sense the multiplicativity of the Lie Poisson structure on SU(2) at the classical level is preserved under quantization. (orig.)

Salty popcorn in a homogeneous low-dimensional toy model of holographic QCD

International Nuclear Information System (INIS)

Elliot-Ripley, Matthew

2017-01-01

Recently, a homogeneous ansatz has been used to study cold dense nuclear matter in the Sakai–Sugimoto model of holographic QCD. To justify this homogeneous approximation we here investigate a homogeneous ansatz within a low-dimensional toy version of Sakai–Sugimoto to study finite baryon density configurations and compare it to full numerical solutions. We find the ansatz corresponds to enforcing a dyon salt arrangement in which the soliton solutions are split into half-soliton layers. Within this ansatz we find analogues of the proposed baryonic popcorn transitions, in which solutions split into multiple layers in the holographic direction. The homogeneous results are found to qualitatively match the full numerical solutions, lending confidence to the homogeneous approximations of the full Sakai–Sugimoto model. In addition, we find exact compact solutions in the high density, flat space limit which demonstrate the existence of further popcorn transitions to three layers and beyond. (paper)

International Conference on Geometric and Harmonic Analysis on Homogeneous Spaces and Applications

CERN Document Server

Nomura, Takaaki

2017-01-01

This book provides the latest competing research results on non-commutative harmonic analysis on homogeneous spaces with many applications. It also includes the most recent developments on other areas of mathematics including algebra and geometry. Lie group representation theory and harmonic analysis on Lie groups and on their homogeneous spaces form a significant and important area of mathematical research. These areas are interrelated with various other mathematical fields such as number theory, algebraic geometry, differential geometry, operator algebra, partial differential equations and mathematical physics.  Keeping up with the fast development of this exciting area of research, Ali Baklouti (University of Sfax) and Takaaki Nomura (Kyushu University) launched a series of seminars on the topic, the first of which took place on November 2009 in Kerkennah Islands, the second in Sousse  on December 2011, and the third in Hammamet& nbsp;on December 2013. The last seminar, which took place on Dece...

Molecular decompostition of anisotropic homogeneous mixed-norm spaces with applications to the boundedness of operators

DEFF Research Database (Denmark)

Cleanthous, Galatia; Georgiadis, Athanasios; Nielsen, Morten

2018-01-01

. Molecular decompositions for all the considered spaces are derived with the help of the algebra of almost diagonal operators. As an application, we obtain boundedness results on the considered spaces for Fourier multipliers and for pseudodifferential operators with suitable adapted homogeneous symbols using...

Scattering of targets over layered half space using a semi-analytic method in conjunction with FDTD algorithm.

Science.gov (United States)

Cao, Le; Wei, Bing

2014-08-25

Finite-difference time-domain (FDTD) algorithm with a new method of plane wave excitation is used to investigate the RCS (Radar Cross Section) characteristics of targets over layered half space. Compare with the traditional excitation plane wave method, the calculation memory and time requirement is greatly decreased. The FDTD calculation is performed with a plane wave incidence, and the RCS of far field is obtained by extrapolating the currently calculated data on the output boundary. However, methods available for extrapolating have to evaluate the half space Green function. In this paper, a new method which avoids using the complex and time-consuming half space Green function is proposed. Numerical results show that this method is in good agreement with classic algorithm and it can be used in the fast calculation of scattering and radiation of targets over layered half space.

Rules of Thumb for Depth of Investigation, Pseudo-Position and Resolution of the Electrical Resistivity Method from Analysis of the Moments of the Sensitivity Function for a Homogeneous Half-Space

Science.gov (United States)

Butler, S. L.

2017-12-01

The electrical resistivity method is now highly developed with 2D and even 3D surveys routinely performed and with available fast inversion software. However, rules of thumb, based on simple mathematical formulas, for important quantities like depth of investigation, horizontal position and resolution have not previously been available and would be useful for survey planning, preliminary interpretation and general education about the method. In this contribution, I will show that the sensitivity function for the resistivity method for a homogeneous half-space can be analyzed in terms of its first and second moments which yield simple mathematical formulas. The first moment gives the sensitivity-weighted center of an apparent resistivity measurement with the vertical center being an estimate of the depth of investigation. I will show that this depth of investigation estimate works at least as well as previous estimates based on the peak and median of the depth sensitivity function which must be calculated numerically for a general four electrode array. The vertical and horizontal first moments can also be used as pseudopositions when plotting 1, 2 and 3D pseudosections. The appropriate horizontal plotting point for a pseudosection was not previously obvious for nonsymmetric arrays. The second moments of the sensitivity function give estimates of the spatial extent of the region contributing to an apparent resistivity measurement and hence are measures of the resolution. These also have simple mathematical formulas.

Renormalization of a tensorial field theory on the homogeneous space SU(2)/U(1)

Science.gov (United States)

Lahoche, Vincent; Oriti, Daniele

2017-01-01

We study the renormalization of a general field theory on the homogeneous space (SU(2)/ ≤ft. U(1)\\right){{}× d} with tensorial interaction and gauge invariance under the diagonal action of SU(2). We derive the power counting for arbitrary d. For the case d  =  4, we prove perturbative renormalizability to all orders via multi-scale analysis, study both the renormalized and effective perturbation series, and establish the asymptotic freedom of the model. We also outline a general power counting for the homogeneous space {{≤ft(SO(D)/SO(D-1)\\right)}× d} , of direct interest for quantum gravity models in arbitrary dimension, and point out the obstructions to the direct generalization of our results to these cases.

Toeplitz Operators, Pseudo-Homogeneous Symbols, and Moment Maps on the Complex Projective Space

Directory of Open Access Journals (Sweden)

Miguel Antonio Morales-Ramos

2017-01-01

Full Text Available Following previous works for the unit ball due to Nikolai Vasilevski, we define quasi-radial pseudo-homogeneous symbols on the projective space and obtain the corresponding commutativity results for Toeplitz operators. A geometric interpretation of these symbols in terms of moment maps is developed. This leads us to the introduction of a new family of symbols, extended pseudo-homogeneous, that provide larger commutative Banach algebras generated by Toeplitz operators. This family of symbols provides new commutative Banach algebras generated by Toeplitz operators on the unit ball.

Converting boundary representation solid models to half-space representation models for Monte Carlo analysis

International Nuclear Information System (INIS)

Davis, J. E.; Eddy, M. J.; Sutton, T. M.; Altomari, T. J.

2007-01-01

Solid modeling computer software systems provide for the design of three-dimensional solid models used in the design and analysis of physical components. The current state-of-the-art in solid modeling representation uses a boundary representation format in which geometry and topology are used to form three-dimensional boundaries of the solid. The geometry representation used in these systems is cubic B-spline curves and surfaces - a network of cubic B-spline functions in three-dimensional Cartesian coordinate space. Many Monte Carlo codes, however, use a geometry representation in which geometry units are specified by intersections and unions of half-spaces. This paper describes an algorithm for converting from a boundary representation to a half-space representation. (authors)

Vibration of an Elastic Circular Plate on an Elastic Half Space

DEFF Research Database (Denmark)

Krenk, Steen; Schmidt, H.

1981-01-01

The axisymmetric problem of a vibrating elastic plate on an elastic half space is solved by a direct method, in which the contact stresses and the normal displacements of the plate are taken as the unknown functions. First, the influence functions that give the displacements in terms...

Lossy compression of TPC data and trajectory tracking efficiency for the ALICE experiment

International Nuclear Information System (INIS)

Nicolaucig, A.; Ivanov, M.; Mattavelli, M.

2003-01-01

In this paper a quasi-lossless algorithm for the on-line compression of the data generated by the Time Projection Chamber (TPC) detector of the ALICE experiment at CERN is described. The algorithm is based on a lossy source code modeling technique, i.e. it is based on a source model which is lossy if samples of the TPC signal are considered one by one; conversely, the source model is lossless or quasi-lossless if some physical quantities that are of main interest for the experiment are considered. These quantities are the area and the location of the center of mass of each TPC signal pulse, representing the pulse charge and the time localization of the pulse. So as to evaluate the consequences of the error introduced by the lossy compression process, the results of the trajectory tracking algorithms that process data off-line after the experiment are analyzed, in particular, versus their sensibility to the noise introduced by the compression. Two different versions of these off-line algorithms are described, performing cluster finding and particle tracking. The results on how these algorithms are affected by the lossy compression are reported. Entropy coding can be applied to the set of events defined by the source model to reduce the bit rate to the corresponding source entropy. Using TPC simulated data according to the expected ALICE TPC performance, the compression algorithm achieves a data reduction in the range of 34.2% down to 23.7% of the original data rate depending on the desired precision on the pulse center of mass. The number of operations per input symbol required to implement the algorithm is relatively low, so that a real-time implementation of the compression process embedded in the TPC data acquisition chain using low-cost integrated electronics is a realistic option to effectively reduce the data storing cost of ALICE experiment

Solution of the Korteweg--de Vries equation in a half-space bounded by a wall

International Nuclear Information System (INIS)

Moses, H.E.

1976-01-01

A solution of the Korteweg--de Vries equation in the half-space 0 less than r less than infinity with the boundary condition V(0) = 0 is given. The boundary condition may be interpreted as the requirement that the plane which bounds the half-space be a rigid wall. Aside from possible physical interest, this solution, which is obtained from one of the potentials for the radial Schroedinger equation which do not scatter, appears to indicate that the radial Schroedinger equation and the corresponding Gel'fand--Levitan equation play a role in the case of the half-space bounded by a wall similar to that of the one-dimensional Schroedinger equation (-- infinity less than x less than infinity) and its corresponding Gel'fand--Levitan equation in the more usual full space treatment of the KdV equation. A possible interpretation of the solution presented is that it corresponds to the reflection of a wave by a wall, in which the incident wave is singular and the reflected wave is nonsingular but highly dispersive

Lossi legendist, tamme teekonnast ja maali mõistatusest / Alar Läänelaid

Index Scriptorium Estoniae

Läänelaid, Alar, 1951-

2006-01-01

Dendrokronoloogilisest dateerimisest (aastarõngasdateerimine), mis on toonud selgust Alatskivi lossi söögisaali laekaunistuse dateerimisse, Hans van Esseni maali "Vaikelu homaariga" ning Clara Peetersi "Vaikelu jahisaagiga" valmimisaja ja ehtsuse kindlaksmääramisse

Scaling a network with positive gains to a lossy or gainy network

NARCIS (Netherlands)

Koene, J.

1979-01-01

Necessary and sufficient conditions are presented under which it is possible to scale a network with positive gains to a lossy or a gainy network. A procedure to perform such a scaling operation is given.

Using off-the-shelf lossy compression for wireless home sleep staging.

Science.gov (United States)

Lan, Kun-Chan; Chang, Da-Wei; Kuo, Chih-En; Wei, Ming-Zhi; Li, Yu-Hung; Shaw, Fu-Zen; Liang, Sheng-Fu

2015-05-15

Recently, there has been increasing interest in the development of wireless home sleep staging systems that allow the patient to be monitored remotely while remaining in the comfort of their home. However, transmitting large amount of Polysomnography (PSG) data over the Internet is an important issue needed to be considered. In this work, we aim to reduce the amount of PSG data which has to be transmitted or stored, while having as little impact as possible on the information in the signal relevant to classify sleep stages. We examine the effects of off-the-shelf lossy compression on an all-night PSG dataset from 20 healthy subjects, in the context of automated sleep staging. The popular compression method Set Partitioning in Hierarchical Trees (SPIHT) was used, and a range of compression levels was selected in order to compress the signals with various degrees of loss. In addition, a rule-based automatic sleep staging method was used to automatically classify the sleep stages. Considering the criteria of clinical usefulness, the experimental results show that the system can achieve more than 60% energy saving with a high accuracy (>84%) in classifying sleep stages by using a lossy compression algorithm like SPIHT. As far as we know, our study is the first that focuses how much loss can be tolerated in compressing complex multi-channel PSG data for sleep analysis. We demonstrate the feasibility of using lossy SPIHT compression for wireless home sleep staging. Copyright © 2015 Elsevier B.V. All rights reserved.

Lossi hoovis mälestati veretöö ohvreid / Veljo Kuivjõgi

Index Scriptorium Estoniae

Kuivjõgi, Veljo, 1951-

2006-01-01

Endel Püüa raamatu "Punane terror Saaremaal 1941. aastal" (Saaremaa : Saaremaa Muuseum, 2006) esitlusest ja mälestuspäevast, mis oli pühendatud kõigile ohvritele, kes hukati 1941. aasta suvel Kuressaare lossi hoovis

Far-field dynamic behavior of a half-space under an inertial strip foundation subjected to a time-harmonic force

Directory of Open Access Journals (Sweden)

M. Dehestani

Full Text Available Recent research works demonstrated that the interaction between the loads and the carrying structure's boundary which is related to the inertia of the load is an influential factor on the dynamic response of the structure. Although effects of the inertia in moving loads were considered in many works, very few papers can be found on the inertial effects of the stationary loads on structures. In this paper, an elastodynamic formulation was employed to investigate the dynamic response of a homogeneous isotropic elastic half-space under an inertial strip foundation subjected to a time-harmonic force. Fourier integral transformation was used to solve the system of Poisson-type partial differential equation considering the boundary conditions and the inertial effects. Steepest descent method was employed to obtain the approximate far-field displacements and stresses. A numerical example is presented to illustrate the methodology and typical results.

Plane strain deformation of a multi-layered poroelastic half-space by ...

Indian Academy of Sciences (India)

The Biot linearized quasi-static theory of fluid-infiltrated porous materials is used to formulate the problem of the two-dimensional plane strain deformation of a multi-layered poroelastic half-space by surface loads. The Fourier–Laplace transforms of the stresses, displacements, pore pressure and fluid flux in each ...

Homogeneous anisotropic solutions of topologically massive gravity with a cosmological constant and their homogeneous deformations

International Nuclear Information System (INIS)

Moutsopoulos, George

2013-01-01

We solve the equations of topologically massive gravity (TMG) with a potentially non-vanishing cosmological constant for homogeneous metrics without isotropy. We only reproduce known solutions. We also discuss their homogeneous deformations, possibly with isotropy. We show that de Sitter space and hyperbolic space cannot be infinitesimally homogeneously deformed in TMG. We clarify some of their Segre–Petrov types and discuss the warped de Sitter spacetime. (paper)

Homogeneous anisotropic solutions of topologically massive gravity with a cosmological constant and their homogeneous deformations

Science.gov (United States)

Moutsopoulos, George

2013-06-01

We solve the equations of topologically massive gravity (TMG) with a potentially non-vanishing cosmological constant for homogeneous metrics without isotropy. We only reproduce known solutions. We also discuss their homogeneous deformations, possibly with isotropy. We show that de Sitter space and hyperbolic space cannot be infinitesimally homogeneously deformed in TMG. We clarify some of their Segre-Petrov types and discuss the warped de Sitter spacetime.

Diffraction of SH-waves by topographic features in a layered transversely isotropic half-space

Science.gov (United States)

Ba, Zhenning; Liang, Jianwen; Zhang, Yanju

2017-01-01

The scattering of plane SH-waves by topographic features in a layered transversely isotropic (TI) half-space is investigated by using an indirect boundary element method (IBEM). Firstly, the anti-plane dynamic stiffness matrix of the layered TI half-space is established and the free fields are solved by using the direct stiffness method. Then, Green's functions are derived for uniformly distributed loads acting on an inclined line in a layered TI half-space and the scattered fields are constructed with the deduced Green's functions. Finally, the free fields are added to the scattered ones to obtain the global dynamic responses. The method is verified by comparing results with the published isotropic ones. Both the steady-state and transient dynamic responses are evaluated and discussed. Numerical results in the frequency domain show that surface motions for the TI media can be significantly different from those for the isotropic case, which are strongly dependent on the anisotropy property, incident angle and incident frequency. Results in the time domain show that the material anisotropy has important effects on the maximum duration and maximum amplitudes of the time histories.

Rocking Rotation of a Rigid Disk Embedded in a Transversely Isotropic Half-Space

Directory of Open Access Journals (Sweden)

Seyed Ahmadi

2014-06-01

Full Text Available The asymmetric problem of rocking rotation of a circular rigid disk embedded in a finite depth of a transversely isotropic half-space is analytically addressed. The rigid disk is assumed to be in frictionless contact with the elastic half-space. By virtue of appropriate Green's functions, the mixed boundary value problem is written as a dual integral equation. Employing further mathematical techniques, the integral equation is reduced to a well-known Fredholm integral equation of the second kind. The results related to the contact stress distribution across the disk region and the equivalent rocking stiffness of the system are expressed in terms of the solution of the obtained Fredholm  integral  equation. When the rigid disk is located on the surface or at the remote boundary, the exact closed-form solutions are presented. For verification purposes, the limiting case of an isotropic half-space is considered and the results are verified with those available in the literature. The jump behavior in the results at the edge of the rigid disk for the case of an infinitesimal embedment is highlighted analytically for the first time. Selected numerical results are depicted for the contact stress distribution across the disk region, rocking stiffness of the system, normal stress, and displacement components along the radial axis. Moreover, effects of anisotropy on the rocking stiffness factor are discussed in detail.

THERMAL CONSOLIDATION OF LAYERED POROUS HALF-SPACE TO VARIABLE THERMAL LOADING

Institute of Scientific and Technical Information of China (English)

BAI Bing

2006-01-01

An analytical method was derived for the thermal consolidation of layered,saturated porous half-space to variable thermal loading with time. In the coupled governing equations of linear thermoelastic media, the influences of thermo-osmosis effect and thermal filtration effect were introduced. Solutions in Laplace transform space were first obtained and then numerically inverted. The responses of a double-layered porous space subjected to exponential decaying thermal loading were studied. The influences of the differences between the properties of the two layers (e.g., the coefficient of thermal consolidation, elastic modulus) on thermal consolidation were discussed. The studies show that the coupling effects of displacement and stress fields on temperature field can be completely neglected, however, thc thermo-osmosis effect has an obvious influence on thermal responses.

When fast and slow interfaces grow together: Connection to the half-space problem of the Kardar-Parisi-Zhang class

Science.gov (United States)

Ito, Yasufumi; Takeuchi, Kazumasa A.

2018-04-01

We study height fluctuations of interfaces in the (1 +1 ) -dimensional Kardar-Parisi-Zhang (KPZ) class, growing at different speeds in the left half and the right half of space. Carrying out simulations of the discrete polynuclear growth model with two different growth rates, combined with the standard setting for the droplet, flat, and stationary geometries, we find that the fluctuation properties at and near the boundary are described by the KPZ half-space problem developed in the theoretical literature. In particular, in the droplet case, the distribution at the boundary is given by the largest-eigenvalue distribution of random matrices in the Gaussian symplectic ensemble, often called the GSE Tracy-Widom distribution. We also characterize crossover from the full-space statistics to the half-space one, which arises when the difference between the two growth speeds is small.

Tantsufestival Momentum 2008 : Alatskivi lossi tunded, mõtted, emotsioonid / Reet Kruup

Index Scriptorium Estoniae

Kruup, Reet

2008-01-01

25.-27. aprillini Alatskivi Kaunite Kunstide Kuu raames toimunud tantsufestivalist Momentum 2008. Festivalil osalesid Alatskivi vallas tegutsevate tantsurühmade kõrval ka tantsuteater Tee Kuubis, kontakttantsurühmitus Kontakt Tartust ja Tartu Ülikooli Viljandi Kultuuriakadeemia lavakunstide osakonna tudengid, kes esitasid improvisatsioonilise tantsuetenduse "Alatskivi lossi tunded, mõtted, emotsioonid..."

Asymmetric Vibrations of a Circular Elastic Plate on an Elastic Half Space

DEFF Research Database (Denmark)

Schmidt, H.; Krenk, Steen

1982-01-01

The asymmetric problem of a vibrating circular elastic plate in frictionless contact with an elastic half space is solved by an integral equation method, where the contact stress appears as the unknown function. By a trigonometric expansion, the problem is reduced to a number of uncoupled two...

How useful is slow light in enhancing nonlinear interactions in lossy periodic nanostructures?

DEFF Research Database (Denmark)

Saravi, Sina; Quintero-Bermudez, Rafael; Setzpfandt, Frank

2016-01-01

We investigate analytically, and with nonlinear simulations, the extent of usefulness of slow light for enhancing the efficiency of second harmonic generation in lossy nanostructures, and find that the slower is not always the better....

Progress with lossy compression of data from the Community Earth System Model

Science.gov (United States)

Xu, H.; Baker, A.; Hammerling, D.; Li, S.; Clyne, J.

2017-12-01

Climate models, such as the Community Earth System Model (CESM), generate massive quantities of data, particularly when run at high spatial and temporal resolutions. The burden of storage is further exacerbated by creating large ensembles, generating large numbers of variables, outputting at high frequencies, and duplicating data archives (to protect against disk failures). Applying lossy compression methods to CESM datasets is an attractive means of reducing data storage requirements, but ensuring that the loss of information does not negatively impact science objectives is critical. In particular, test methods are needed to evaluate whether critical features (e.g., extreme values and spatial and temporal gradients) have been preserved and to boost scientists' confidence in the lossy compression process. We will provide an overview on our progress in applying lossy compression to CESM output and describe our unique suite of metric tests that evaluate the impact of information loss. Further, we will describe our processes how to choose an appropriate compression algorithm (and its associated parameters) given the diversity of CESM data (e.g., variables may be constant, smooth, change abruptly, contain missing values, or have large ranges). Traditional compression algorithms, such as those used for images, are not necessarily ideally suited for floating-point climate simulation data, and different methods may have different strengths and be more effective for certain types of variables than others. We will discuss our progress towards our ultimate goal of developing an automated multi-method parallel approach for compression of climate data that both maximizes data reduction and minimizes the impact of data loss on science results.

Pointwise Multipliers on Spaces of Homogeneous Type in the Sense of Coifman and Weiss

Directory of Open Access Journals (Sweden)

Yanchang Han

2014-01-01

homogeneous type in the sense of Coifman and Weiss, pointwise multipliers of inhomogeneous Besov and Triebel-Lizorkin spaces are obtained. We make no additional assumptions on the quasi-metric or the doubling measure. Hence, the results of this paper extend earlier related results to a more general setting.

Deformation of two welded elastic half-spaces due to a long inclined ...

Indian Academy of Sciences (India)

2Department of Mathematics, University of Delhi South Campus, New Delhi 110 021, India. ∗e-mail: ... Airy stress function for a tensile line source in two welded half-spaces are first obtained. These expressions ... computing the displacement and stress fields around a long inclined tensile fault near an internal boundary. 1.

Mathematical Modeling of Torsional Surface Wave Propagation in a Non-Homogeneous Transverse Isotropic Elastic Solid Semi-Infinite Medium Under a Layer

Science.gov (United States)

Sethi, M.; Sharma, A.; Vasishth, A.

2017-05-01

The present paper deals with the mathematical modeling of the propagation of torsional surface waves in a non-homogeneous transverse isotropic elastic half-space under a rigid layer. Both rigidities and density of the half-space are assumed to vary inversely linearly with depth. Separation of variable method has been used to get the analytical solutions for the dispersion equation of the torsional surface waves. Also, the effects of nonhomogeneities on the phase velocity of torsional surface waves have been shown graphically. Also, dispersion equations have been derived for some particular cases, which are in complete agreement with some classical results.

Three examples of quantum dynamics on the half-line with smooth bouncing

Science.gov (United States)

Almeida, C. R.; Bergeron, H.; Gazeau, J.-P.; Scardua, A. C.

2018-05-01

This article is an introductory presentation of the quantization of the half-plane based on affine coherent states (ACS). The half-plane carries a natural affine symmetry, i.e. it is a homogeneous space for the 1d-affine group, and it is viewed as the phase space for the dynamics of a positive physical quantity evolving with time. Its affine symmetry is preserved due to the covariance of this type of quantization. We promote the interest of such a procedure for transforming a classical model into a quantum one, since the singularity at the origin is systematically removed, and the arbitrariness of boundary conditions for the Schrödinger operator can be easily overcome. We explain some important mathematical aspects of the method. Three elementary examples of applications are presented, the quantum breathing of a massive sphere, the quantum smooth bouncing of a charged sphere, and a smooth bouncing of "dust" sphere as a simple model of quantum Newtonian cosmology.

A two dimensional fibre reinforced micropolar thermoelastic problem for a half-space subjected to mechanical force

Directory of Open Access Journals (Sweden)

Ailawalia Praveen

2015-01-01

Full Text Available The purpose of this paper is to study the two dimensional deformation of fibre reinforced micropolar thermoelastic medium in the context of Green-Lindsay theory of thermoelasticity. A mechanical force is applied along the interface of fluid half space and fibre reinforced micropolar thermoelastic half space. The normal mode analysis has been applied to obtain the exact expressions for displacement component, force stress, temperature distribution and tangential couple stress. The effect of anisotropy and micropolarity on the displacement component, force stress, temperature distribution and tangential couple stress has been depicted graphically.

Direct current electric potential in an anisotropic half-space with vertical contact containing a conductive 3D body

Directory of Open Access Journals (Sweden)

Li Ping

2004-01-01

Full Text Available Detailed studies of anomalous conductors in otherwise homogeneous media have been modelled. Vertical contacts form common geometries in galvanic studies when describing geological formations with different electrical conductivities on either side. However, previous studies of vertical discontinuities have been mainly concerned with isotropic environments. In this paper, we deal with the effect on the electric potentials, such as mise-à-la-masse anomalies, due to a conductor near a vertical contact between two anisotropic regions. We also demonstrate the interactive effects when the conductive body is placed across the vertical contact. This problem is normally very difficult to solve by the traditional numerical methods. The integral equations for the electric potential in anisotropic half-spaces are established. Green's function is obtained using the reflection and transmission image method in which five images are needed to fit the boundary conditions on the vertical interface and the air-earth surface. The effects of the anisotropy of the environments and the conductive body on the electric potential are illustrated with the aid of several numerical examples.

A lossy graph model for delay reduction in generalized instantly decodable network coding

KAUST Repository

Douik, Ahmed S.; Sorour, Sameh; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2014-01-01

, arising from lossy feedback events, when the expected decoding delay of XORing them among themselves or with other certain packets is lower than that expected when sending these packets separately. We compare the decoding delay performance of LG-IDNC and G

A solution of the monoenergetic neutral particle transport equation for adjacent half-spaces with anisotropic scattering

Energy Technology Data Exchange (ETDEWEB)

Ganapol, B.D., E-mail: ganapol@cowboy.ame.arizona.edu [Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ (United States); Mostacci, D.; Previti, A. [Montecuccolino Laboratory, University of Bologna, Via dei Colli, 16, I-40136 Bologna (Italy)

2016-07-01

We present highly accurate solutions to the neutral particle transport equation in a half-space. While our initial motivation was in response to a recently published solution based on Chandrasekhar's H-function, the presentation to follow has taken on a more comprehensive tone. The solution by H-functions certainly did achieved high accuracy but was limited to isotropic scattering and emission from spatially uniform and linear sources. Moreover, the overly complicated nature of the H-function approach strongly suggests that its extension to anisotropic scattering and general sources is not at all practical. For this reason, an all encompassing theory for the determination of highly precise benchmarks, including anisotropic scattering for a variety of spatial source distributions, is presented for particle transport in a half-space. We illustrate the approach via a collection of cases including tables of 7-place flux benchmarks to guide transport methods developers. The solution presented can be applied to a considerable number of one and two half-space transport problems with variable sources and represents a state-of-the-art benchmark solution.

A Good $\\lambda$ Estimate for Multilinear Commutator of Singular Integral on Spaces of Homogeneous Type

Directory of Open Access Journals (Sweden)

Zhang Qian

2011-04-01

Full Text Available In this paper, a good $\\lambda$ estimate for the multilinear commutator associated to the singular integral operator on the spaces of homogeneous type is obtained. Under this result, we get the$(L^p(X,L^q(X$-boundedness of the multilinear commutator.

Commutators of Littlewood-Paley gκ∗$g_{\\kappa}^{*} $-functions on non-homogeneous metric measure spaces

Directory of Open Access Journals (Sweden)

Lu Guanghui

2017-11-01

Full Text Available The main purpose of this paper is to prove that the boundedness of the commutator Mκ,b∗$\\mathcal{M}_{\\kappa,b}^{*} $ generated by the Littlewood-Paley operator Mκ∗$\\mathcal{M}_{\\kappa}^{*} $ and RBMO (μ function on non-homogeneous metric measure spaces satisfying the upper doubling and the geometrically doubling conditions. Under the assumption that the kernel of Mκ∗$\\mathcal{M}_{\\kappa}^{*} $ satisfies a certain Hörmander-type condition, the authors prove that Mκ,b∗$\\mathcal{M}_{\\kappa,b}^{*} $ is bounded on Lebesgue spaces Lp(μ for 1 < p < ∞, bounded from the space L log L(μ to the weak Lebesgue space L1,∞(μ, and is bounded from the atomic Hardy spaces H1(μ to the weak Lebesgue spaces L1,∞(μ.

Volumetric Medical Image Coding: An Object-based, Lossy-to-lossless and Fully Scalable Approach

Science.gov (United States)

Danyali, Habibiollah; Mertins, Alfred

2011-01-01

In this article, an object-based, highly scalable, lossy-to-lossless 3D wavelet coding approach for volumetric medical image data (e.g., magnetic resonance (MR) and computed tomography (CT)) is proposed. The new method, called 3DOBHS-SPIHT, is based on the well-known set partitioning in the hierarchical trees (SPIHT) algorithm and supports both quality and resolution scalability. The 3D input data is grouped into groups of slices (GOS) and each GOS is encoded and decoded as a separate unit. The symmetric tree definition of the original 3DSPIHT is improved by introducing a new asymmetric tree structure. While preserving the compression efficiency, the new tree structure allows for a small size of each GOS, which not only reduces memory consumption during the encoding and decoding processes, but also facilitates more efficient random access to certain segments of slices. To achieve more compression efficiency, the algorithm only encodes the main object of interest in each 3D data set, which can have any arbitrary shape, and ignores the unnecessary background. The experimental results on some MR data sets show the good performance of the 3DOBHS-SPIHT algorithm for multi-resolution lossy-to-lossless coding. The compression efficiency, full scalability, and object-based features of the proposed approach, beside its lossy-to-lossless coding support, make it a very attractive candidate for volumetric medical image information archiving and transmission applications. PMID:22606653

Closely spaced mirror pair for reshaping and homogenizing pump beams in laser amplifiers

International Nuclear Information System (INIS)

Bass, I.L.

1992-12-01

Channeling a laser beam by multiple reflections between two closely-spaced, parallel or nearly parallel mirrors, serves to reshape and homogenize the beam at the output gap between the mirrors. Application of this device to improve the spatial overlap of a copper laser pump beam with the signal beam in a dye laser amplifier is described. This technique has been applied to the AVLIS program at the Lawrence Livermore National Laboratory

Receiver-Assisted Congestion Control to Achieve High Throughput in Lossy Wireless Networks

Science.gov (United States)

Shi, Kai; Shu, Yantai; Yang, Oliver; Luo, Jiarong

2010-04-01

Many applications would require fast data transfer in high-speed wireless networks nowadays. However, due to its conservative congestion control algorithm, Transmission Control Protocol (TCP) cannot effectively utilize the network capacity in lossy wireless networks. In this paper, we propose a receiver-assisted congestion control mechanism (RACC) in which the sender performs loss-based control, while the receiver is performing delay-based control. The receiver measures the network bandwidth based on the packet interarrival interval and uses it to compute a congestion window size deemed appropriate for the sender. After receiving the advertised value feedback from the receiver, the sender then uses the additive increase and multiplicative decrease (AIMD) mechanism to compute the correct congestion window size to be used. By integrating the loss-based and the delay-based congestion controls, our mechanism can mitigate the effect of wireless losses, alleviate the timeout effect, and therefore make better use of network bandwidth. Simulation and experiment results in various scenarios show that our mechanism can outperform conventional TCP in high-speed and lossy wireless environments.

Diffraction of an inhomogeneous plane wave by an impedance wedge in a lossy medium

CSIR Research Space (South Africa)

Manara, G

1998-11-01

Full Text Available The diffraction of an inhomogeneous plane wave by an impedance wedge embedded in a lossy medium is analyzed. The rigorous integral representation for the field is asymptotically evaluated in the context of the uniform geometrical theory...

Gravitational influences on the liquid-state homogenization and solidification of aluminum antimonide. [space processing of solar cell material

Science.gov (United States)

Ang, C.-Y.; Lacy, L. L.

1979-01-01

Typical commercial or laboratory-prepared samples of polycrystalline AlSb contain microstructural inhomogeneities of Al- or Sb-rich phases in addition to the primary AlSb grains. The paper reports on gravitational influences, such as density-driven convection or sedimentation, that cause microscopic phase separation and nonequilibrium conditions to exist in earth-based melts of AlSb. A triple-cavity electric furnace is used to homogenize the multiphase AlSb samples in space and on earth. A comparative characterization of identically processed low- and one-gravity samples of commercial AlSb reveals major improvements in the homogeneity of the low-gravity homogenized material.

Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change

Science.gov (United States)

Delaney, P.

1984-01-01

Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

High-altitude electromagnetic pulse environment over the lossy ground

International Nuclear Information System (INIS)

Xie Yanzhao; Wang Zanji

2003-01-01

The electromagnetic field above ground produced by an incident high-altitude electromagnetic pulse plane wave striking the ground plane was described in this paper in terms of the Fresnel reflection coefficients and the numerical FFT. The pulse reflected from the ground plane always cancel the incident field for the horizontal field component, but the reflected field adds to the incident for the vertical field component. The results of several cases for variations in the observation height, angle of incidence and lossy ground electrical parameters were also presented showing different e-field components above the earth

Monoenergetic neutral particle transport in an anisotropically scattering half-space

International Nuclear Information System (INIS)

Ganapol, B.D.; Garth, J.C.; Woolf, S.

1995-01-01

During the past several years, a considerable effort has been underway to develop reliable analytical benchmark solutions to the one-speed transport equation in various geometries. The reader may well ask open-quotes whyclose quotes such a task has been undertaken, given the recent rapid advances in numerical transport theory. The simple answer is that reliable numerical solutions do not yet exist, and their development still represents a mathematical challenge. However, regardless of how mathematically challenging the development is, there are more compelling reasons for this effort which are rooted in the very fundamentals of science and technology. In particular, these solutions, which are highly accurate numerical evaluations of analytical solution representations, serve as open-quotes industry standardsclose quotes to which other more approximate methods or approximations can be compared. Thus analytical benchmarks are part of the process control and continuous improvement of numerical transport methods and are therefore integral components in TQM (Total Quality Management) as applied to transport methods development. With the above reasoning in mind, the authors begin the development and application of a new analytical solution and evaluation for a half-space featuring anisotropic scattering. This work is an extension of previous efforts in which isotropically scattering half-spaces were treated. The previous benchmarks were obtained most conveniently via a numerical Laplace transform inversion which could be applied in a straightforward manner to the case of isotropic scattering. The application of the Laplace transform method is problematical for anisotropic scattering and does not admit to the direct identification of the scalar flux from integral transport theory

Toward maximum transmittance into absorption layers in solar cells: investigation of lossy-film-induced mismatches between reflectance and transmittance extrema.

Science.gov (United States)

Chang, Yin-Jung; Lai, Chi-Sheng

2013-09-01

The mismatch in film thickness and incident angle between reflectance and transmittance extrema due to the presence of lossy film(s) is investigated toward the maximum transmittance design in the active region of solar cells. Using a planar air/lossy film/silicon double-interface geometry illustrates important and quite opposite mismatch behaviors associated with TE and TM waves. In a typical thin-film CIGS solar cell, mismatches contributed by TM waves in general dominate. The angular mismatch is at least 10° in about 37%-53% of the spectrum, depending on the thickness combination of all lossy interlayers. The largest thickness mismatch of a specific interlayer generally increases with the thickness of the layer itself. Antireflection coating designs for solar cells should therefore be optimized in terms of the maximum transmittance into the active region, even if the corresponding reflectance is not at its minimum.

Deformation of a layered half-space due to a very long tensile fault

Indian Academy of Sciences (India)

The problem of the coseismic deformation of an earth model consisting of an elastic layer of uniform thickness overlying an elastic half-space due to a very long tensile fault in the layer is solved analytically. Integral expressions for the surface displacements are obtained for a vertical tensile fault and a horizontal tensile fault.

Reducing disk storage of full-3D seismic waveform tomography (F3DT) through lossy online compression

Science.gov (United States)

Lindstrom, Peter; Chen, Po; Lee, En-Jui

2016-08-01

Full-3D seismic waveform tomography (F3DT) is the latest seismic tomography technique that can assimilate broadband, multi-component seismic waveform observations into high-resolution 3D subsurface seismic structure models. The main drawback in the current F3DT implementation, in particular the scattering-integral implementation (F3DT-SI), is the high disk storage cost and the associated I/O overhead of archiving the 4D space-time wavefields of the receiver- or source-side strain tensors. The strain tensor fields are needed for computing the data sensitivity kernels, which are used for constructing the Jacobian matrix in the Gauss-Newton optimization algorithm. In this study, we have successfully integrated a lossy compression algorithm into our F3DT-SI workflow to significantly reduce the disk space for storing the strain tensor fields. The compressor supports a user-specified tolerance for bounding the error, and can be integrated into our finite-difference wave-propagation simulation code used for computing the strain fields. The decompressor can be integrated into the kernel calculation code that reads the strain fields from the disk and compute the data sensitivity kernels. During the wave-propagation simulations, we compress the strain fields before writing them to the disk. To compute the data sensitivity kernels, we read the compressed strain fields from the disk and decompress them before using them in kernel calculations. Experiments using a realistic dataset in our California statewide F3DT project have shown that we can reduce the strain-field disk storage by at least an order of magnitude with acceptable loss, and also improve the overall I/O performance of the entire F3DT-SI workflow significantly. The integration of the lossy online compressor may potentially open up the possibilities of the wide adoption of F3DT-SI in routine seismic tomography practices in the near future.

Experimental measurements of the eddy current signal due to a flawed, conducting half space

International Nuclear Information System (INIS)

Long, S.A.; Toomsawasdi, S.; Zaman, A.J.M.

1984-01-01

This chapter reports on an experimental investigation in which the change in impedance of a practical multi-turn eddy current coil near a conducting half space is measured as a function of the conductivity and the lift-off distance. The results are compared in a qualitative fashion with the analytical results for a single-turn coil. Measurements are also made of the change in impedance due to a small void in the conducting half space as a function of both its depth and radial position. The results indicate that, at least in a qualitative fashion, the precisely derived analytical solutions adequately predict the general behavior of the change in complex impedance of an eddy current coil above a conducting ground plane as a function of lift-off distance. It is determined that the effect of a sub-surface void on the change in inductance of the test coil correlates well with theoretical calculations

Theory and Circuit Model for Lossy Coaxial Transmission Line

Energy Technology Data Exchange (ETDEWEB)

Genoni, T. C.; Anderson, C. N.; Clark, R. E.; Gansz-Torres, J.; Rose, D. V.; Welch, Dale Robert

2017-04-01

The theory of signal propagation in lossy coaxial transmission lines is revisited and new approximate analytic formulas for the line impedance and attenuation are derived. The accuracy of these formulas from DC to 100 GHz is demonstrated by comparison to numerical solutions of the exact field equations. Based on this analysis, a new circuit model is described which accurately reproduces the line response over the entire frequency range. Circuit model calculations are in excellent agreement with the numerical and analytic results, and with finite-difference-time-domain simulations which resolve the skindepths of the conducting walls.

Impact of a half-space interface on the wireless link between tiny sensor nodes

NARCIS (Netherlands)

Penkin, D.; Janssen, G.; Yarovoy, A.

2014-01-01

The power budget of a wireless link between two electrically small sensor nodes located close to an interface between two media is studied. The model includes both the propagation channel losses and input impedance of the radio frequency antennas. It is shown that a highly inductive half-space

Integrated Circuit Interconnect Lines on Lossy Silicon Substrate with Finite Element Method

OpenAIRE

Sarhan M. Musa,; Matthew N. O. Sadiku

2014-01-01

The silicon substrate has a significant effect on the inductance parameter of a lossy interconnect line on integrated circuit. It is essential to take this into account in determining the transmission line electrical parameters. In this paper, a new quasi-TEM capacitance and inductance analysis of multiconductor multilayer interconnects is successfully demonstrated using finite element method (FEM). We specifically illustrate the electrostatic modeling of single and coupled in...

Generation of exact solutions to the Einstein field equations for homogeneous space--time

International Nuclear Information System (INIS)

Hiromoto, R.E.

1978-01-01

A formalism is presented capable of finding all homogeneous solutions of the Einstein field equations with an arbitrary energy-stress tensor. Briefly the method involves the classification of the four-dimensional Lie algebra over the reals into nine different broad classes, using only the Lorentz group. Normally the classification of Lie algebras means that one finds all essentially different solutions of the Jacobi identities, i.e., there exists no nonsingular linear transformation which transforms two sets of structure constants into the other. This approach is to utilize the geometrical considerations of the homogeneous spacetime and field equations to be solved. Since the set of orthonormal basis vectors is not only endowed with a Minkowskian metric, but also constitutes the vector space of our four-dimensional Lie algebras, the Lie algebras are classified against the Lorentz group restricts the linear group of transformations, denoting the essentially different Lie algebras, into nine different broad classes. The classification of the four-dimensional Lie algebras represents the unification of various methods previously introduced by others. Where their methods found only specific solutions to the Einstein field equations, systematic application of the nine different classes of Lie algebras guarantees the extraction of all solutions. Therefore, the methods of others were extended, and their foundations of formalism which goes beyond the present literature of exact homogeneous solutions to the Einstein field equations is built upon

String pair production in non homogeneous backgrounds

Energy Technology Data Exchange (ETDEWEB)

Bolognesi, S. [Department of Physics “E. Fermi” University of Pisa, and INFN - Sezione di Pisa,Largo Pontecorvo, 3, Ed. C, 56127 Pisa (Italy); Rabinovici, E. [Racah Institute of Physics, The Hebrew University of Jerusalem,91904 Jerusalem (Israel); Tallarita, G. [Departamento de Ciencias, Facultad de Artes Liberales,Universidad Adolfo Ibáñez, Santiago 7941169 (Chile)

2016-04-28

We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

String pair production in non homogeneous backgrounds

International Nuclear Information System (INIS)

Bolognesi, S.; Rabinovici, E.; Tallarita, G.

2016-01-01

We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

Lossy effects on the lateral shifts in negative-phase-velocity medium

International Nuclear Information System (INIS)

You Yuan

2009-01-01

Theoretical investigations of the lateral shifts of the reflected and transmitted beams were performed, using the stationary-phase approach, for the planar interface of a conventional medium and a lossy negative-phase-velocity medium. The lateral shifts exhibit different behaviors beyond and below a certain angle, for both incident p-polarized and incident s-polarized plane waves. Loss in the negative-phase-velocity medium affects lateral shifts greatly, and may cause changes from negative to positive values for p-polarized incidence

A Note on Classification of Spatially Homogeneous Rotating Space-Times According to Their Teleparallel Killing Vector Fields in Teleparallel Theory of Gravitation

International Nuclear Information System (INIS)

Shabbir, Ghulam; Khan, Suhail; Ali, Amjad

2011-01-01

In this paper we classify spatially homogeneous rotating space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the teleparallel Killing vector fields is 5 or 10. In the case of 10 teleparallel Killing vector fields the space-time becomes Minkowski and all the torsion components are zero. Teleparallel Killing vector fields in this case are exactly the same as in general relativity. In the cases of 5 teleparallel Killing vector fields we get two more conservation laws in the teleparallel theory of gravitation. Here we also discuss some well-known examples of spatially homogeneous rotating space-times according to their teleparallel Killing vector fields. (general)

Shape differentiability of the Neumann problem of the Laplace equation in the half-space

Czech Academy of Sciences Publication Activity Database

Amrouche, Ch.; Nečasová, Šárka; Sokolowski, J.

2008-01-01

Roč. 37, č. 4 (2008), s. 748-769 ISSN 0324-8569 R&D Projects: GA ČR GA201/05/0005; GA ČR GA201/08/0012 Institutional research plan: CEZ:AV0Z10190503 Keywords : shape optimization * Neumann problem * half space * material derivative Subject RIV: BA - General Mathematics Impact factor: 0.689, year: 2008

Propagation of waves at the loosely bonded interface of two porous elastic half-spaces

International Nuclear Information System (INIS)

Tajuddin, M.

1993-10-01

Employing Biot's theory for wave propagation in porous solids, the propagation of waves at the loosely bonded interface between two poroelastic half-spaces is examined theoretically. The analogous study of Stoneley waves for smooth interface and bonded interface form a limiting case. The results due to classical theory are shown as a special case. (author). 13 refs

Wigner-Kirkwood expansion of the phase-space density for half infinite nuclear matter

International Nuclear Information System (INIS)

Durand, M.; Schuck, P.

1987-01-01

The phase space distribution of half infinite nuclear matter is expanded in a ℎ-series analogous to the low temperature expansion of the Fermi function. Besides the usual Wigner-Kirkwood expansion, oscillatory terms are derived. In the case of a Woods-Saxon potential, a smallness parameter is defined, which determines the convergence of the series and explains the very rapid convergence of the Wigner-Kirkwood expansion for average (nuclear) binding energies

Contact problem for a solid indenter and a viscoelastic half-space described by the spectrum of relaxation and retardation times

Science.gov (United States)

Stepanov, F. I.

2018-04-01

The mechanical properties of a material which is modeled by an exponential creep kernel characterized by a spectrum of relaxation and retardation times are studied. The research is carried out considering a contact problem for a solid indenter sliding over a viscoelastic half-space. The contact pressure, indentation depth of the indenter, and the deformation component of the friction coefficient are analyzed with respect to the case of half-space material modeled by single relaxation and retardation times.

Efficient Lossy Compression for Compressive Sensing Acquisition of Images in Compressive Sensing Imaging Systems

Directory of Open Access Journals (Sweden)

Xiangwei Li

2014-12-01

Full Text Available Compressive Sensing Imaging (CSI is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity.

Security of modified Ping-Pong protocol in noisy and lossy channel

OpenAIRE

Han, Yun-Guang; Yin, Zhen-Qiang; Li, Hong-Wei; Chen, Wei; Wang, Shuang; Guo, Guang-Can; Han, Zheng-Fu

2014-01-01

The “Ping-Pong” (PP) protocol is a two-way quantum key protocol based on entanglement. In this protocol, Bob prepares one maximally entangled pair of qubits, and sends one qubit to Alice. Then, Alice performs some necessary operations on this qubit and sends it back to Bob. Although this protocol was proposed in 2002, its security in the noisy and lossy channel has not been proven. In this report, we add a simple and experimentally feasible modification to the original PP protocol, and prove ...

Short-distance expansion for the electromagnetic half-space Green's tensor: general results and an application to radiative lifetime computations

International Nuclear Information System (INIS)

Panasyuk, George Y; Schotland, John C; Markel, Vadim A

2009-01-01

We obtain a short-distance expansion for the half-space, frequency domain electromagnetic Green's tensor. The small parameter of the theory is ωε 1 L/c, where ω is the frequency, ε 1 is the permittivity of the upper half-space, in which both the source and the point of observation are located, and which is assumed to be transparent, c is the speed of light in vacuum and L is a characteristic length, defined as the distance from the point of observation to the reflected (with respect to the planar interface) position of the source. In the case when the lower half-space (the substrate) is characterized by a complex permittivity ε 2 , we compute the expansion to third order. For the case when the substrate is a transparent dielectric, we compute the imaginary part of the Green's tensor to seventh order. The analytical calculations are verified numerically. The practical utility of the obtained expansion is demonstrated by computing the radiative lifetime of two electromagnetically interacting molecules in the vicinity of a transparent dielectric substrate. The computation is performed in the strong interaction regime when the quasi-particle pole approximation is inapplicable. In this regime, the integral representation for the half-space Green's tensor is difficult to use while its electrostatic limiting expression is grossly inadequate. However, the analytical expansion derived in this paper can be used directly and efficiently. The results of this study are also relevant to nano-optics and near-field imaging, especially when tomographic image reconstruction is involved

Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

DEFF Research Database (Denmark)

Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

2014-01-01

For spherical antennas consisting of a solid magnetodielectric lossy core with an impressed surface current density exciting a superposition of the ${\\rm TE}_{mn}$ and ${\\rm TM}_{mn}$ spherical modes, we analytically determine the radiation quality factor $Q$ and radiation efficiency $e$ . Also, we...

Homogeneous Poisson structures

International Nuclear Information System (INIS)

Shafei Deh Abad, A.; Malek, F.

1993-09-01

We provide an algebraic definition for Schouten product and give a decomposition for any homogenenous Poisson structure in any n-dimensional vector space. A large class of n-homogeneous Poisson structures in R k is also characterized. (author). 4 refs

2-D Deformation analysis of a half-space due to a long dip-slip fault ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

tic deformation in a uniform half-space due to long faults has been attempted by a number of researchers. Singh and Rani (1996) presented step- by-step progress made in the direction of crustal deformation modeling associated with strike-slip and dip-slip faulting in the earth. Cohen (1996) gave convenient formulas for ...

Mach's principle in spatially homogeneous spacetimes

International Nuclear Information System (INIS)

Tipler, F.J.

1978-01-01

On the basis of Mach's Principle it is concluded that the only singularity-free solution to the empty space Einstein equations is flat space. It is shown that the only singularity-free solution to the empty space Einstein equations which is spatially homogeneous and globally hyperbolic is in fact suitably identified Minkowski space. (Auth.)

Cross section homogenization analysis for a simplified Candu reactor

International Nuclear Information System (INIS)

Pounders, Justin; Rahnema, Farzad; Mosher, Scott; Serghiuta, Dumitru; Turinsky, Paul; Sarsour, Hisham

2008-01-01

The effect of using zero current (infinite medium) boundary conditions to generate bundle homogenized cross sections for a stylized half-core Candu reactor problem is examined. Homogenized cross section from infinite medium lattice calculations are compared with cross sections homogenized using the exact flux from the reference core environment. The impact of these cross section differences is quantified by generating nodal diffusion theory solutions with both sets of cross sections. It is shown that the infinite medium spatial approximation is not negligible, and that ignoring the impact of the heterogeneous core environment on cross section homogenization leads to increased errors, particularly near control elements and the core periphery. (authors)

A Lossy Counting-Based State of Charge Estimation Method and Its Application to Electric Vehicles

Directory of Open Access Journals (Sweden)

Hong Zhang

2015-12-01

Full Text Available Estimating the residual capacity or state-of-charge (SoC of commercial batteries on-line without destroying them or interrupting the power supply, is quite a challenging task for electric vehicle (EV designers. Many Coulomb counting-based methods have been used to calculate the remaining capacity in EV batteries or other portable devices. The main disadvantages of these methods are the cumulative error and the time-varying Coulombic efficiency, which are greatly influenced by the operating state (SoC, temperature and current. To deal with this problem, we propose a lossy counting-based Coulomb counting method for estimating the available capacity or SoC. The initial capacity of the tested battery is obtained from the open circuit voltage (OCV. The charging/discharging efficiencies, used for compensating the Coulombic losses, are calculated by the lossy counting-based method. The measurement drift, resulting from the current sensor, is amended with the distorted Coulombic efficiency matrix. Simulations and experimental results show that the proposed method is both effective and convenient.

Poisson-Jacobi reduction of homogeneous tensors

International Nuclear Information System (INIS)

Grabowski, J; Iglesias, D; Marrero, J C; Padron, E; Urbanski, P

2004-01-01

The notion of homogeneous tensors is discussed. We show that there is a one-to-one correspondence between multivector fields on a manifold M, homogeneous with respect to a vector field Δ on M, and first-order polydifferential operators on a closed submanifold N of codimension 1 such that Δ is transversal to N. This correspondence relates the Schouten-Nijenhuis bracket of multivector fields on M to the Schouten-Jacobi bracket of first-order polydifferential operators on N and generalizes the Poissonization of Jacobi manifolds. Actually, it can be viewed as a super-Poissonization. This procedure of passing from a homogeneous multivector field to a first-order polydifferential operator can also be understood as a sort of reduction; in the standard case-a half of a Poisson reduction. A dual version of the above correspondence yields in particular the correspondence between Δ-homogeneous symplectic structures on M and contact structures on N

Adiabatic passage for a lossy two-level quantum system by a complex time method

International Nuclear Information System (INIS)

Dridi, G; Guérin, S

2012-01-01

Using a complex time method with the formalism of Stokes lines, we establish a generalization of the Davis–Dykhne–Pechukas formula which gives in the adiabatic limit the transition probability of a lossy two-state system driven by an external frequency-chirped pulse-shaped field. The conditions that allow this generalization are derived. We illustrate the result with the dissipative Allen–Eberly and Rosen–Zener models. (paper)

2-D deformation of two welded half-spaces due to a blind dip-slip fault

Indian Academy of Sciences (India)

The solution of two-dimensional problem of an interface breaking long inclined dip-slip fault in two welded half-spaces is well known.The purpose of this note is to obtain the corresponding solution for a blind fault.The solution is valid for arbitrary values of the fault-depth and the dip angle.Graphs showing the variation of the ...

LOW COMPLEXITY HYBRID LOSSY TO LOSSLESS IMAGE CODER WITH COMBINED ORTHOGONAL POLYNOMIALS TRANSFORM AND INTEGER WAVELET TRANSFORM

Directory of Open Access Journals (Sweden)

R. Krishnamoorthy

2012-05-01

Full Text Available In this paper, a new lossy to lossless image coding scheme combined with Orthogonal Polynomials Transform and Integer Wavelet Transform is proposed. The Lifting Scheme based Integer Wavelet Transform (LS-IWT is first applied on the image in order to reduce the blocking artifact and memory demand. The Embedded Zero tree Wavelet (EZW subband coding algorithm is used in this proposed work for progressive image coding which achieves efficient bit rate reduction. The computational complexity of lower subband coding of EZW algorithm is reduced in this proposed work with a new integer based Orthogonal Polynomials transform coding. The normalization and mapping are done on the subband of the image for exploiting the subjective redundancy and the zero tree structure is obtained for EZW coding and so the computation complexity is greatly reduced in this proposed work. The experimental results of the proposed technique also show that the efficient bit rate reduction is achieved for both lossy and lossless compression when compared with existing techniques.

Analytical representation of the solution of the space kinetic diffusion equation in a one-dimensional and homogeneous domain

Energy Technology Data Exchange (ETDEWEB)

Tumelero, Fernanda; Bodmann, Bardo E. J.; Vilhena, Marco T. [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos Graduacao em Engenharia Mecanica; Lapa, Celso M.F., E-mail: fernanda.tumelero@yahoo.com.br, E-mail: bardo.bodmann@ufrgs.br, E-mail: mtmbvilhena@gmail.com, E-mail: lapa@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

In this work we solve the space kinetic diffusion equation in a one-dimensional geometry considering a homogeneous domain, for two energy groups and six groups of delayed neutron precursors. The proposed methodology makes use of a Taylor expansion in the space variable of the scalar neutron flux (fast and thermal) and the concentration of delayed neutron precursors, allocating the time dependence to the coefficients. Upon truncating the Taylor series at quadratic order, one obtains a set of recursive systems of ordinary differential equations, where a modified decomposition method is applied. The coefficient matrix is split into two, one constant diagonal matrix and the second one with the remaining time dependent and off-diagonal terms. Moreover, the equation system is reorganized such that the terms containing the latter matrix are treated as source terms. Note, that the homogeneous equation system has a well known solution, since the matrix is diagonal and constant. This solution plays the role of the recursion initialization of the decomposition method. The recursion scheme is set up in a fashion where the solutions of the previous recursion steps determine the source terms of the subsequent steps. A second feature of the method is the choice of the initial and boundary conditions, which are satisfied by the recursion initialization, while from the rst recursion step onward the initial and boundary conditions are homogeneous. The recursion depth is then governed by a prescribed accuracy for the solution. (author)

Design of a receiver operating characteristic (ROC) study of 10:1 lossy image compression

Science.gov (United States)

Collins, Cary A.; Lane, David; Frank, Mark S.; Hardy, Michael E.; Haynor, David R.; Smith, Donald V.; Parker, James E.; Bender, Gregory N.; Kim, Yongmin

1994-04-01

The digital archiving system at Madigan Army Medical Center (MAMC) uses a 10:1 lossy data compression algorithm for most forms of computed radiography. A systematic study on the potential effect of lossy image compression on patient care has been initiated with a series of studies focused on specific diagnostic tasks. The studies are based upon the receiver operating characteristic (ROC) method of analysis for diagnostic systems. The null hypothesis is that observer performance with approximately 10:1 compressed and decompressed images is not different from using original, uncompressed images for detecting subtle pathologic findings seen on computed radiographs of bone, chest, or abdomen, when viewed on a high-resolution monitor. Our design involves collecting cases from eight pathologic categories. Truth is determined by committee using confirmatory studies performed during routine clinical practice whenever possible. Software has been developed to aid in case collection and to allow reading of the cases for the study using stand-alone Siemens Litebox workstations. Data analysis uses two methods, ROC analysis and free-response ROC (FROC) methods. This study will be one of the largest ROC/FROC studies of its kind and could benefit clinical radiology practice using PACS technology. The study design and results from a pilot FROC study are presented.

CaloCube: an innovative homogeneous calorimeter for the next-generation space experiments

Science.gov (United States)

Pacini, L.; Adriani, O.; Agnesi, A.; Albergo, S.; Auditore, L.; Basti, A.; Berti, E.; Bigongiari, G.; Bonechi, L.; Bonechi, S.; Bongi, M.; Bonvicini, V.; Bottai, S.; Brogi, P.; Cappello, G.; Carotenuto, G.; Castellini, G.; Cattaneo, P. W.; Chiari, M.; Daddi, N.; DAlessandro, R.; Detti, S.; Fasoli, M.; Finetti, N.; Lenzi, P.; Maestro, P.; Marrocchesi, P. S.; Miritello, M.; Mori, N.; Orzan, G.; Olmi, M.; Papini, P.; Pellegriti, M. G.; Pirzio, F.; Rappoldi, A.; Ricciarini, S.; Spillantini, P.; Starodubtsev, O.; Stolzi, F.; Suh, J. E.; Sulaj, A.; Tiberio, A.; Tricomi, A.; Trifirò, A.; Trimarchi, M.; Vannuccini, E.; Vedda, A.; Zampa, G.; Zampa, N.

2017-11-01

The direct measurement of the cosmic-ray spectrum, up to the knee region, is one of the instrumental challenges for next generation space experiments. The main issue for these measurements is a steeply falling spectrum with increasing energy, so the physics performance of the space calorimeters are primarily determined by their geometrical acceptance and energy resolution. CaloCube is a three-year R&D project, approved and financed by INFN in 2014, aiming to optimize the design of a space-born calorimeter. The peculiarity of the design of CaloCube is its capability of detecting particles coming from any direction, and not only those on its upper surface. To ensure that the quality of the measurement does not depend on the arrival direction of the particles, the calorimeter will be designed as homogeneous and isotropic as possible. In addition, to achieve a high discrimination power for hadrons and nuclei with respect to electrons, the sensitive elements of the calorimeter need to have a fine 3-D sampling capability. In order to optimize the detector performances with respect to the total mass of the apparatus, which is the most important constraint for a space launch, a comparative study of different scintillating materials has been performed using detailed Monte Carlo simulation based on the FLUKA package. In parallel to simulation studies, a prototype consisting in 14 layers of 3 x 3 CsI(Tl) crystals per layer has been assembled and tested with particle beams. An overview of the obtained results during the first two years of the project will be presented and the future of the detector will be discussed too.

Modular Hamiltonians for deformed half-spaces and the averaged null energy condition

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Faulkner, Thomas; Leigh, Robert G.; Parrikar, Onkar; Wang, Huajia

2016-09-01

We study modular Hamiltonians corresponding to the vacuum state for deformed half-spaces in relativistic quantum field theories on {{R}}^{1,d-1} . We show that in addition to the usual boost generator, there is a contribution to the modular Hamiltonian at first order in the shape deformation, proportional to the integral of the null components of the stress tensor along the Rindler horizon. We use this fact along with monotonicity of relative entropy to prove the averaged null energy condition in Minkowski space-time. This subsequently gives a new proof of the Hofman-Maldacena bounds on the parameters appearing in CFT three-point functions. Our main technical advance involves adapting newly developed perturbative methods for calculating entanglement entropy to the problem at hand. These methods were recently used to prove certain results on the shape dependence of entanglement in CFTs and here we generalize these results to excited states and real time dynamics. We also discuss the AdS/CFT counterpart of this result, making connection with the recently proposed gravitational dual for modular Hamiltonians in holographic theories.

Regularities of magnetic field penetration into half-space in type-II superconductors

International Nuclear Information System (INIS)

Medvedev, Yu.V.; Krasnyuk, I.B.

2003-01-01

The equations, modeling the distributions of the magnetic field induction and current density in the half-space with an account of the exponential volt-ampere characteristics, are obtained. The velocity of the magnetization front propagation by the assigned average rate of the change by the time of the external magnetic field at the sample boundary is determined. The integral condition for the electric resistance, nonlinearly dependent on the magnetic field, by accomplishing whereof the magnetic flux penetrates into the sample with the finite velocity is indicated. The analytical representation of the equation with the exponential boundary mode, which models the change in the magnetic field at the area boundary, is pointed out [ru

The combinational structure of non-homogeneous Markov chains with countable states

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A. Mukherjea

1983-01-01

Full Text Available Let P(s,t denote a non-homogeneous continuous parameter Markov chain with countable state space E and parameter space [a,b], −∞0}. It is shown in this paper that R(s,t is reflexive, transitive, and independent of (s,t, shomogeneity condition holds. It is also shown that the relation R(s,t, unlike in the finite state space case, cannot be expressed even as an infinite (countable product of reflexive transitive relations for certain non-homogeneous chains in the case when E is infinite.

Impact of lossy compression on diagnostic accuracy of radiographs for periapical lesions

Science.gov (United States)

Eraso, Francisco E.; Analoui, Mostafa; Watson, Andrew B.; Rebeschini, Regina

2002-01-01

OBJECTIVES: The purpose of this study was to evaluate the lossy Joint Photographic Experts Group compression for endodontic pretreatment digital radiographs. STUDY DESIGN: Fifty clinical charge-coupled device-based, digital radiographs depicting periapical areas were selected. Each image was compressed at 2, 4, 8, 16, 32, 48, and 64 compression ratios. One root per image was marked for examination. Images were randomized and viewed by four clinical observers under standardized viewing conditions. Each observer read the image set three times, with at least two weeks between each reading. Three pre-selected sites per image (mesial, distal, apical) were scored on a five-scale score confidence scale. A panel of three examiners scored the uncompressed images, with a consensus score for each site. The consensus score was used as the baseline for assessing the impact of lossy compression on the diagnostic values of images. The mean absolute error between consensus and observer scores was computed for each observer, site, and reading session. RESULTS: Balanced one-way analysis of variance for all observers indicated that for compression ratios 48 and 64, there was significant difference between mean absolute error of uncompressed and compressed images (P <.05). After converting the five-scale score to two-level diagnostic values, the diagnostic accuracy was strongly correlated (R (2) = 0.91) with the compression ratio. CONCLUSION: The results of this study suggest that high compression ratios can have a severe impact on the diagnostic quality of the digital radiographs for detection of periapical lesions.

Three-dimensional coupled thermoelastodynamic stress and flux induced wave propagation for isotropic half-space with scalar potential functions

Science.gov (United States)

Hayati, Yazdan; Eskandari-Ghadi, Morteza

2018-02-01

An asymmetric three-dimensional thermoelastodynamic wave propagation with scalar potential functions is presented for an isotropic half-space, in such a way that the wave may be originated from an arbitrary either traction or heat flux applied on a patch at the free surface of the half-space. The displacements, stresses and temperature are presented within the framework of Biot's coupled thermoelasticity formulations. By employing a complete representation for the displacement and temperature fields in terms of two scalar potential functions, the governing equations of coupled thermoelasticity are uncoupled into a sixth- and a second-order partial differential equation in cylindrical coordinate system. By virtue of Fourier expansion and Hankel integral transforms, the angular and radial variables are suppressed respectively, and a 6{th}- and a 2{nd}-order ordinary differential equation in terms of depth are received, which are solved readily, from which the displacement, stresses and temperature fields are derived in transformed space by satisfying both the regularity and boundary conditions. By applying the inverse Hankel integral transforms, the displacements and temperature are numerically evaluated to determine the solutions in the real space. The numerical evaluations are done for three specific cases of vertical and horizontal time-harmonic patch traction and a constant heat flux passing through a circular disc on the surface of the half-space. It has been previously proved that the potential functions used in this paper are applicable from elastostatics to thermoelastodynamics. Thus, the analytical solutions presented in this paper are verified by comparing the results of this study with two specific problems reported in the literature, which are an elastodynamic problem and an axisymmetric quasi-static thermoelastic problem. To show the accuracy of numerical results, the solution of this study is also compared with the solution for elastodynamics exists in

A microcontroller-based interface circuit for lossy capacitive sensors

International Nuclear Information System (INIS)

Reverter, Ferran; Casas, Òscar

2010-01-01

This paper introduces and analyses a low-cost microcontroller-based interface circuit for lossy capacitive sensors, i.e. sensors whose parasitic conductance (G x ) is not negligible. Such a circuit relies on a previous circuit also proposed by the authors, in which the sensor is directly connected to a microcontroller without using either a signal conditioner or an analogue-to-digital converter in the signal path. The novel circuit uses the same hardware, but it performs an additional measurement and executes a new calibration technique. As a result, the sensitivity of the circuit to G x decreases significantly (a factor higher than ten), but not completely due to the input capacitances of the port pins of the microcontroller. Experimental results show a relative error in the capacitance measurement below 1% for G x x ) shows the effectiveness of the circuit

Numerical analysis of the propagation characteristics of Stoneley waves at an interface between microstretch thermoelastic diffusion solid half spaces

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Rajneesh Kumar

Full Text Available This paper is concerned with the study of propagation of Stoneley waves at the interface of two dissimilar isotropic microstretch thermoelastic diffusion medium in the context of generalized theories of thermoelasticity. The dispersion equation of Stoneley waves is derived in the form of a determinant by using the boundary conditions. The dispersion curves giving the phase velocity and attenuation coefficients with wave number are computed numerically. Numerically computed results are shown graphically to depict the diffusion effect alongwith the relaxation times in microstretch thermoelastic diffusion solid half spaces for thermally insulated and impermeable boundaries, respectively. The components of displacement, stress, couple stress, microstress, and temperature change are presented graphically for two dissimilar microstretch thermoelastic diffusion half-spaces. Several cases of interest under different conditions are also deduced and discussed.

On a Poisson homogeneous space of bilinear forms with a Poisson-Lie action

Science.gov (United States)

Chekhov, L. O.; Mazzocco, M.

2017-12-01

Let \\mathscr A be the space of bilinear forms on C^N with defining matrices A endowed with a quadratic Poisson structure of reflection equation type. The paper begins with a short description of previous studies of the structure, and then this structure is extended to systems of bilinear forms whose dynamics is governed by the natural action A\\mapsto B ABT} of the {GL}_N Poisson-Lie group on \\mathscr A. A classification is given of all possible quadratic brackets on (B, A)\\in {GL}_N× \\mathscr A preserving the Poisson property of the action, thus endowing \\mathscr A with the structure of a Poisson homogeneous space. Besides the product Poisson structure on {GL}_N× \\mathscr A, there are two other (mutually dual) structures, which (unlike the product Poisson structure) admit reductions by the Dirac procedure to a space of bilinear forms with block upper triangular defining matrices. Further generalisations of this construction are considered, to triples (B,C, A)\\in {GL}_N× {GL}_N× \\mathscr A with the Poisson action A\\mapsto B ACT}, and it is shown that \\mathscr A then acquires the structure of a Poisson symmetric space. Generalisations to chains of transformations and to the quantum and quantum affine algebras are investigated, as well as the relations between constructions of Poisson symmetric spaces and the Poisson groupoid. Bibliography: 30 titles.

Lossy and retardation effects on the localization of EM waves using a left-handed medium slab

International Nuclear Information System (INIS)

Cheng Qiang; Cui Tiejun; Lu Weibing

2005-01-01

It has been shown that a left-handed medium (LHM) slab with negative permittivity -ε0 and negative permeability -μ0 can be used to localize electromagnetic waves [T.J. Cui et al., Phys. Rev. B (January 2005)]. If two current sources with the same amplitudes and opposite directions are placed at the perfect-imaging points of the LHM slab, we have shown that all electromagnetic waves are completely confined in a region between the two sources. In this Letter, a slightly mismatched and lossy LHM lens is studied, where both the relative permittivity and permeability are slightly different from -1, and the lossy and retardation effects on the electromagnetic-wave localization are investigated. Due to the loss and retardation, strong surface waves exist along the slab surfaces. When two current sources are located at the perfect imaging points symmetrically, we show that electromagnetic waves are nearly confined in the region between the two sources and few energies are radiated outside if the retardation and loss are small. When the loss becomes larger, more energies will flow out of the region. Numerical experiments are given to illustrate the above conclusions

ChIPWig: a random access-enabling lossless and lossy compression method for ChIP-seq data.

Science.gov (United States)

Ravanmehr, Vida; Kim, Minji; Wang, Zhiying; Milenkovic, Olgica

2018-03-15

Chromatin immunoprecipitation sequencing (ChIP-seq) experiments are inexpensive and time-efficient, and result in massive datasets that introduce significant storage and maintenance challenges. To address the resulting Big Data problems, we propose a lossless and lossy compression framework specifically designed for ChIP-seq Wig data, termed ChIPWig. ChIPWig enables random access, summary statistics lookups and it is based on the asymptotic theory of optimal point density design for nonuniform quantizers. We tested the ChIPWig compressor on 10 ChIP-seq datasets generated by the ENCODE consortium. On average, lossless ChIPWig reduced the file sizes to merely 6% of the original, and offered 6-fold compression rate improvement compared to bigWig. The lossy feature further reduced file sizes 2-fold compared to the lossless mode, with little or no effects on peak calling and motif discovery using specialized NarrowPeaks methods. The compression and decompression speed rates are of the order of 0.2 sec/MB using general purpose computers. The source code and binaries are freely available for download at https://github.com/vidarmehr/ChIPWig-v2, implemented in C ++. milenkov@illinois.edu. Supplementary data are available at Bioinformatics online.

Sink-to-Sink Coordination Framework Using RPL: Routing Protocol for Low Power and Lossy Networks

Directory of Open Access Journals (Sweden)

Meer M. Khan

2016-01-01

Full Text Available RPL (Routing Protocol for low power and Lossy networks is recommended by Internet Engineering Task Force (IETF for IPv6-based LLNs (Low Power and Lossy Networks. RPL uses a proactive routing approach and each node always maintains an active path to the sink node. Sink-to-sink coordination defines syntax and semantics for the exchange of any network defined parameters among sink nodes like network size, traffic load, mobility of a sink, and so forth. The coordination allows sink to learn about the network condition of neighboring sinks. As a result, sinks can make coordinated decision to increase/decrease their network size for optimizing over all network performance in terms of load sharing, increasing network lifetime, and lowering end-to-end latency of communication. Currently, RPL does not provide any coordination framework that can define message exchange between different sink nodes for enhancing the network performance. In this paper, a sink-to-sink coordination framework is proposed which utilizes the periodic route maintenance messages issued by RPL to exchange network status observed at a sink with its neighboring sinks. The proposed framework distributes network load among sink nodes for achieving higher throughputs and longer network’s life time.

Uniform color space is not homogeneous

Science.gov (United States)

Kuehni, Rolf G.

2002-06-01

Historical data of chroma scaling and hue scaling are compared and evidence is shown that we do not have a reliable basis in either case. Several data sets indicate explicitly or implicitly that the number of constant sized hue differences between unique hues as well as in the quadrants of the a*, b* diagram differs making what is commonly regarded as uniform color space inhomogeneous. This problem is also shown to affect the OSA-UCS space. A Euclidean uniform psychological or psychophysical color space appears to be impossible.

Wave energy transfer in elastic half-spaces with soft interlayers.

Science.gov (United States)

Glushkov, Evgeny; Glushkova, Natalia; Fomenko, Sergey

2015-04-01

The paper deals with guided waves generated by a surface load in a coated elastic half-space. The analysis is based on the explicit integral and asymptotic expressions derived in terms of Green's matrix and given loads for both laminate and functionally graded substrates. To perform the energy analysis, explicit expressions for the time-averaged amount of energy transferred in the time-harmonic wave field by every excited guided or body wave through horizontal planes and lateral cylindrical surfaces have been also derived. The study is focused on the peculiarities of wave energy transmission in substrates with soft interlayers that serve as internal channels for the excited guided waves. The notable features of the source energy partitioning in such media are the domination of a single emerging mode in each consecutive frequency subrange and the appearance of reverse energy fluxes at certain frequencies. These effects as well as modal and spatial distribution of the wave energy coming from the source into the substructure are numerically analyzed and discussed.

The influence of pore-fluid in the soil on ground vibrations from a tunnel embedded in a layered half-space

Science.gov (United States)

Yuan, Zonghao; Cao, Zhigang; Boström, Anders; Cai, Yuanqiang

2018-04-01

A computationally efficient semi-analytical solution for ground-borne vibrations from underground railways is proposed and used to investigate the influence of hydraulic boundary conditions at the scattering surfaces and the moving ground water table on ground vibrations. The arrangement of a dry soil layer with varying thickness resting on a saturated poroelastic half-space, which includes a circular tunnel subject to a harmonic load at the tunnel invert, creates the scenario of a moving water table for research purposes in this paper. The tunnel is modelled as a hollow cylinder, which is made of viscoelastic material and buried in the half-space below the ground water table. The wave field in the dry soil layer consists of up-going and down-going waves while the wave field in the tunnel wall consists of outgoing and regular cylindrical waves. The complete solution for the saturated half-space with a cylindrical hole is composed of down-going plane waves and outgoing cylindrical waves. By adopting traction-free boundary conditions on the ground surface and continuity conditions at the interfaces of the two soil layers and of the tunnel and the surrounding soil, a set of algebraic equations can be obtained and solved in the transformed domain. Numerical results show that the moving ground water table can cause an uncertainty of up to 20 dB for surface vibrations.

Gestion participative du sanctuaire de gorilles de plaine de l'ouest (Gorilla gorilla gorilla de Lossi en République du Congo- Brazzaville: première analyse de résultats et des contraintes

Directory of Open Access Journals (Sweden)

Mbété, RA.

2007-01-01

Full Text Available Participative Management of the Sanctuary of Western Lowland Gorillas (Gorilla gorilla gorilla of Lossi in Republic of Congo-Brazzaville: Preliminary Results and Constraints Analysis. The gorilla sanctuary of Lossi experiments the synergy between scientific research and nature conservation. Three partners are involved in a management participative process. These partners include the Republic of Congo, the local community of Lossi and the European programme on the forest ecosystems in Central Africa. An investigation was carried out on the sanctuary of Lossi in 2003, in order to study in situ the effects generated by the participative management and to identify the constraints linked to the participative approach. The work of primatologists allowed the habituation of the gorillas to the human presence and opened eyesight tourism of western lowland gorillas. A camp for tourists and the access road to the sanctuary have been constructed. The tourism generated jobs in favour of the local population which is also a take-partner of contracts on road repairing. The income from the tourism allowed the construction of a health centre. However, the works of researchers and tourism activities failed during the outbreaks of the Ebola hemorrhagic fever and during the three civil war episodes. The consolidation and the long term of this process of co-management of natural resources of Lossi remains the establishment of a management that should include conservation, rural development and scientific research, with equitably in the distribution of gain between the partnerses.

Singular perturbations with boundary conditions and the Casimir effect in the half space

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Albeverio, S.; Cognola, G.; Spreafico, M.; Zerbini, S.

2010-06-01

We study the self-adjoint extensions of a class of nonmaximal multiplication operators with boundary conditions. We show that these extensions correspond to singular rank 1 perturbations (in the sense of Albeverio and Kurasov [Singular Perturbations of Differential Operaters (Cambridge University Press, Cambridge, 2000)]) of the Laplace operator, namely, the formal Laplacian with a singular delta potential, on the half space. This construction is the appropriate setting to describe the Casimir effect related to a massless scalar field in the flat space-time with an infinite conducting plate and in the presence of a pointlike "impurity." We use the relative zeta determinant (as defined in the works of Müller ["Relative zeta functions, relative determinants and scattering theory," Commun. Math. Phys. 192, 309 (1998)] and Spreafico and Zerbini ["Finite temperature quantum field theory on noncompact domains and application to delta interactions," Rep. Math. Phys. 63, 163 (2009)]) in order to regularize the partition function of this model. We study the analytic extension of the associated relative zeta function, and we present explicit results for the partition function and for the Casimir force.

Modeling of video traffic in packet networks, low rate video compression, and the development of a lossy+lossless image compression algorithm

Science.gov (United States)

Sayood, K.; Chen, Y. C.; Wang, X.

1992-01-01

During this reporting period we have worked on three somewhat different problems. These are modeling of video traffic in packet networks, low rate video compression, and the development of a lossy + lossless image compression algorithm, which might have some application in browsing algorithms. The lossy + lossless scheme is an extension of work previously done under this grant. It provides a simple technique for incorporating browsing capability. The low rate coding scheme is also a simple variation on the standard discrete cosine transform (DCT) coding approach. In spite of its simplicity, the approach provides surprisingly high quality reconstructions. The modeling approach is borrowed from the speech recognition literature, and seems to be promising in that it provides a simple way of obtaining an idea about the second order behavior of a particular coding scheme. Details about these are presented.

Analysis of a multigroup stylized CANDU half-core benchmark

International Nuclear Information System (INIS)

Pounders, Justin M.; Rahnema, Farzad; Serghiuta, Dumitru

2011-01-01

Highlights: → This paper provides a benchmark that is a stylized model problem in more than two energy groups that is realistic with respect to the underlying physics. → An 8-group cross section library is provided to augment a previously published 2-group 3D stylized half-core CANDU benchmark problem. → Reference eigenvalues and selected pin and bundle fission rates are included. → 2-, 4- and 47-group Monte Carlo solutions are compared to analyze homogenization-free transport approximations that result from energy condensation. - Abstract: An 8-group cross section library is provided to augment a previously published 2-group 3D stylized half-core Canadian deuterium uranium (CANDU) reactor benchmark problem. Reference eigenvalues and selected pin and bundle fission rates are also included. This benchmark is intended to provide computational reactor physicists and methods developers with a stylized model problem in more than two energy groups that is realistic with respect to the underlying physics. In addition to transport theory code verification, the 8-group energy structure provides reactor physicist with an ideal problem for examining cross section homogenization and collapsing effects in a full-core environment. To this end, additional 2-, 4- and 47-group full-core Monte Carlo benchmark solutions are compared to analyze homogenization-free transport approximations incurred as a result of energy group condensation.

The functional half-life of an mRNA depends on the ribosome spacing in an early coding region

DEFF Research Database (Denmark)

Pedersen, Margit; Nissen, Søren; Mitarai, Namiko

2011-01-01

Bacterial mRNAs are translated by closely spaced ribosomes and degraded from the 5'-end, with half-lives of around 2 min at 37 °C in most cases. Ribosome-free or "naked" mRNA is known to be readily degraded, but the initial event that inactivates the mRNA functionally has not been fully described...

Exact Polynomial Eigenmodes for Homogeneous Spherical 3-Manifolds

OpenAIRE

Weeks, Jeffrey R.

2005-01-01

Observational data hints at a finite universe, with spherical manifolds such as the Poincare dodecahedral space tentatively providing the best fit. Simulating the physics of a model universe requires knowing the eigenmodes of the Laplace operator on the space. The present article provides explicit polynomial eigenmodes for all globally homogeneous 3-manifolds: the Poincare dodecahedral space S3/I*, the binary octahedral space S3/O*, the binary tetrahedral space S3/T*, the prism manifolds S3/D...

Studies of imaging characteristics for a slab of a lossy left-handed material

International Nuclear Information System (INIS)

Shen Linfang; He Sailing

2003-01-01

The characteristics of an imaging system formed by a slab of a lossy left-handed material (LHM) are studied. The transfer function of the LHM imaging system is written in an appropriate product form with each term having a clear physical interpretation. A tiny loss of the LHM may suppress the transmission of evanescent waves through the LHM slab and this is explained physically. An analytical expression for the resolution of the imaging system is derived. It is shown that it is impossible to make a subwavelength imaging by using a realistic LHM imaging system unless the LHM slab is much thinner than the wavelength

IPTV multicast with peer-assisted lossy error control

Science.gov (United States)

Li, Zhi; Zhu, Xiaoqing; Begen, Ali C.; Girod, Bernd

2010-07-01

Emerging IPTV technology uses source-specific IP multicast to deliver television programs to end-users. To provide reliable IPTV services over the error-prone DSL access networks, a combination of multicast forward error correction (FEC) and unicast retransmissions is employed to mitigate the impulse noises in DSL links. In existing systems, the retransmission function is provided by the Retransmission Servers sitting at the edge of the core network. In this work, we propose an alternative distributed solution where the burden of packet loss repair is partially shifted to the peer IP set-top boxes. Through Peer-Assisted Repair (PAR) protocol, we demonstrate how the packet repairs can be delivered in a timely, reliable and decentralized manner using the combination of server-peer coordination and redundancy of repairs. We also show that this distributed protocol can be seamlessly integrated with an application-layer source-aware error protection mechanism called forward and retransmitted Systematic Lossy Error Protection (SLEP/SLEPr). Simulations show that this joint PARSLEP/ SLEPr framework not only effectively mitigates the bottleneck experienced by the Retransmission Servers, thus greatly enhancing the scalability of the system, but also efficiently improves the resistance to the impulse noise.

New approach development for solution of cloning results detection problem in lossy saved digital image

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A.A. Kobozeva

2016-09-01

Full Text Available The problem of detection of the digital image falsification results performed by cloning is considered – one of the most often used program tools implemented in all modern graphic editors. Aim: The aim of the work is further development of approach to the solution of a cloning detection problem having the cloned image saved in a lossy format, offered by authors earlier. Materials and Methods: Further development of a new approach to the solution of a problem of cloning results detection in the digital image is presented. Approach is based on the accounting of small changes of cylindrical body volume with the generatrix, that is parallel to the OZ axis, bounded above by the interpolating function plot for a matrix of brightness of the analyzed image, and bounded below by the XOY plane, during the compression process. Results: Adaptation of the offered approach to conditions of the cloned image compression with the arbitrary factor of compression quality is carried out (compression ratio. The approach solvency in the conditions of the cloned image compression according to the algorithms different from the JPEG standard is shown: JPEG2000, compression with use of low-rank approximations of the image matrix (matrix blocks. The results of computational experiment are given. It is shown that the developed approach can be used to detect the results of cloning in digital video in the conditions of lossy compression after cloning process.

The Application of RPL Routing Protocol in Low Power Wireless Sensor and Lossy Networks

Directory of Open Access Journals (Sweden)

Xun Yang

2014-05-01

Full Text Available With the continuous development of computer information technology, wireless sensor has been successfully changed the mode of human life, at the same time, as one of the technologies continues to improve the future life, how to better integration with the RPL routing protocols together become one of research focuses in the current climate. This paper start from the wireless sensor network, briefly discusses the concept, followed by systematic exposition of RPL routing protocol developed background, relevant standards, working principle, topology and related terms, and finally explore the RPL routing protocol in wireless sensor low power lossy network applications.

A new approach of objective quality evaluation on JPEG2000 lossy-compressed lung cancer CT images

Science.gov (United States)

Cai, Weihua; Tan, Yongqiang; Zhang, Jianguo

2007-03-01

Image compression has been used to increase the communication efficiency and storage capacity. JPEG 2000 compression, based on the wavelet transformation, has its advantages comparing to other compression methods, such as ROI coding, error resilience, adaptive binary arithmetic coding and embedded bit-stream. However it is still difficult to find an objective method to evaluate the image quality of lossy-compressed medical images so far. In this paper, we present an approach to evaluate the image quality by using a computer aided diagnosis (CAD) system. We selected 77 cases of CT images, bearing benign and malignant lung nodules with confirmed pathology, from our clinical Picture Archiving and Communication System (PACS). We have developed a prototype of CAD system to classify these images into benign ones and malignant ones, the performance of which was evaluated by the receiver operator characteristics (ROC) curves. We first used JPEG 2000 to compress these cases of images with different compression ratio from lossless to lossy, and used the CAD system to classify the cases with different compressed ratio, then compared the ROC curves from the CAD classification results. Support vector machine (SVM) and neural networks (NN) were used to classify the malignancy of input nodules. In each approach, we found that the area under ROC (AUC) decreases with the increment of compression ratio with small fluctuations.

Slow-light enhanced absorption for bio-chemical sensing applications: potential of low-contrast lossy materials

DEFF Research Database (Denmark)

Pedersen, Jesper Goor; Xiao, Sanshui; Mortensen, Niels Asger

2008-01-01

Slow-light enhanced absorption in liquid-infiltrated photonic crystals has recently been proposed as a route to compensate for the reduced optical path in typical lab-on-a-chip systems for bio-chemical sensing applications. A simple perturbative expression has been applied to ideal structures...... composed of lossless dielectrics. In this work we study the enhancement in structures composed of lossy dielectrics such as a polymer. For this particular sensing application we find that the material loss has an unexpected limited drawback and surprisingly, it may even add to increase the bandwidth...

Smooth homogeneous structures in operator theory

CERN Document Server

Beltita, Daniel

2005-01-01

Geometric ideas and techniques play an important role in operator theory and the theory of operator algebras. Smooth Homogeneous Structures in Operator Theory builds the background needed to understand this circle of ideas and reports on recent developments in this fruitful field of research. Requiring only a moderate familiarity with functional analysis and general topology, the author begins with an introduction to infinite dimensional Lie theory with emphasis on the relationship between Lie groups and Lie algebras. A detailed examination of smooth homogeneous spaces follows. This study is illustrated by familiar examples from operator theory and develops methods that allow endowing such spaces with structures of complex manifolds. The final section of the book explores equivariant monotone operators and Kähler structures. It examines certain symmetry properties of abstract reproducing kernels and arrives at a very general version of the construction of restricted Grassmann manifolds from the theory of loo...

Urbanization reduces and homogenizes trait diversity in stream macroinvertebrate communities.

Science.gov (United States)

Barnum, Thomas R; Weller, Donald E; Williams, Meghan

2017-12-01

More than one-half of the world's population lives in urban areas, so quantifying the effects of urbanization on ecological communities is important for understanding whether anthropogenic stressors homogenize communities across environmental and climatic gradients. We examined the relationship of impervious surface coverage (a marker of urbanization) and the structure of stream macroinvertebrate communities across the state of Maryland and within each of Maryland's three ecoregions: Coastal Plain, Piedmont, and Appalachian, which differ in stream geomorphology and community composition. We considered three levels of trait organization: individual traits, unique combinations of traits, and community metrics (functional richness, functional evenness, and functional divergence) and three levels of impervious surface coverage (low [10%]). The prevalence of an individual trait differed very little between low impervious surface and high impervious surface sites. The arrangement of trait combinations in community trait space for each ecoregion differed when impervious surface coverage was low, but the arrangement became more similar among ecoregions as impervious surface coverage increased. Furthermore, trait combinations that occurred only at low or medium impervious surface coverage were clustered in a subset of the community trait space, indicating that impervious surface affected the presence of only a subset of trait combinations. Functional richness declined with increasing impervious surface, providing evidence for environmental filtering. Community metrics that include abundance were also sensitive to increasing impervious surface coverage: functional divergence decreased while functional evenness increased. These changes demonstrate that increasing impervious surface coverage homogenizes the trait diversity of macroinvertebrate communities in streams, despite differences in initial community composition and stream geomorphology among ecoregions. Community

Variations on the planar Landau problem: canonical transformations, a purely linear potential and the half-plane

International Nuclear Information System (INIS)

Govaerts, Jan; Hounkonnou, M Norbert; Mweene, Habatwa V

2009-01-01

The ordinary Landau problem of a charged particle in a plane subjected to a perpendicular homogeneous and static magnetic field is reconsidered from different points of view. The role of phase space canonical transformations and their relation to a choice of gauge in the solution of the problem is addressed. The Landau problem is then extended to different contexts, in particular the singular situation of a purely linear potential term being added as an interaction, for which a complete purely algebraic solution is presented. This solution is then exploited to solve this same singular Landau problem in the half-plane, with as motivation the potential relevance of such a geometry for quantum Hall measurements in the presence of an electric field or a gravitational quantum well.

Variations on the planar Landau problem: canonical transformations, a purely linear potential and the half-plane

Energy Technology Data Exchange (ETDEWEB)

Govaerts, Jan [Center for Particle Physics and Phenomenology (CP3), Institut de Physique Nucleaire, Universite catholique de Louvain (UCL), 2, Chemin du Cyclotron, B-1348 Louvain-la Neuve (Belgium); Hounkonnou, M Norbert [International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 BP 50, Cotonou (Benin); Mweene, Habatwa V [Physics Department, University of Zambia, PO Box 32379, Lusaka (Zambia)], E-mail: Jan.Govaerts@uclouvain.be, E-mail: hounkonnou@yahoo.fr, E-mail: norbert.hounkonnou@cipma.uac.bj, E-mail: habatwamweene@yahoo.com, E-mail: hmweene@unza.zm

2009-12-04

The ordinary Landau problem of a charged particle in a plane subjected to a perpendicular homogeneous and static magnetic field is reconsidered from different points of view. The role of phase space canonical transformations and their relation to a choice of gauge in the solution of the problem is addressed. The Landau problem is then extended to different contexts, in particular the singular situation of a purely linear potential term being added as an interaction, for which a complete purely algebraic solution is presented. This solution is then exploited to solve this same singular Landau problem in the half-plane, with as motivation the potential relevance of such a geometry for quantum Hall measurements in the presence of an electric field or a gravitational quantum well.

A coupled magneto-thermo-elastic problem in a perfectly conducting elastic half-space with thermal relaxation

Directory of Open Access Journals (Sweden)

S. K. Roy-Choudhuri

1990-01-01

Full Text Available In the present paper we consider the magneto-thermo-elastic wave produced by a thermal shock in a perfectly conducting elastic half-space. Here the Lord-Shulman theory of thermoelasticity [1] is used to account for the interaction between the elastic and thermal fields. The solution obtained in analytical form reduces to those of Kaliski and Nowacki [2] when the coupling between the temperature and strain fields and the relaxation time are neglected. The results also agree with those of Massalas and DaLamangas [3] in absence of the thermal relaxation time.

Edge-based compression of cartoon-like images with homogeneous diffusion

DEFF Research Database (Denmark)

Mainberger, Markus; Bruhn, Andrés; Weickert, Joachim

2011-01-01

Edges provide semantically important image features. In this paper a lossy compression method for cartoon-like images is presented, which is based on edge information. Edges together with some adjacent grey/colour values are extracted and encoded using a classical edge detector, binary compressio...

Monrelativistic particle in a magnetic field in two-dimensional Lobachevsky space, the cylindrical coordinates and the Poincare half-plane

International Nuclear Information System (INIS)

Ovsiyu, E.M.

2012-01-01

Exact solutions of the Schrodinger equation in the two-dimensional Riemannian space of negative curvature, the hyperbolic Lobachevsky plane, in the presence of an external magnetic field, which is an analog of a uniform magnetic field in the Minkowski space, are constructed. The description uses the cylindrical and quasi-Cartesian coordinates. The quasi-Cartesian coordinates determine the Poincare half-plane. In the both coordinate systems, the Schrodinger equation is solved exactly, the wave functions are constructed. A generalized formula for energy levels is found, which describes the quantized motion of a particle in a magnetic field in the Lobachevsky plane. (authors)

Properties of Sub-Wavelength Spherical Antennas With Arbitrarily Lossy Magnetodielectric Cores Approaching the Chu Lower Bound

DEFF Research Database (Denmark)

Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

2014-01-01

For a spherical antenna exciting any arbitrary spherical mode, we derive exact closed-form expressions for the dissipated power and stored energy inside (and outside) the lossy magneto-dielectric spherical core, as well as the radiated power, radiation efficiency, and thus the radiation quality...... an increasing magnetic loss tangent initially leads to a decreasing radiation quality factor, but in the limit of a perfect magnetic conductor (PMC) core the dissipated power tends to zero and the radiation quality factor reaches the fundamental Chu lower bound....

Efficient lossy compression implementations of hyperspectral images: tools, hardware platforms, and comparisons

Science.gov (United States)

García, Aday; Santos, Lucana; López, Sebastián.; Callicó, Gustavo M.; Lopez, Jose F.; Sarmiento, Roberto

2014-05-01

Efficient onboard satellite hyperspectral image compression represents a necessity and a challenge for current and future space missions. Therefore, it is mandatory to provide hardware implementations for this type of algorithms in order to achieve the constraints required for onboard compression. In this work, we implement the Lossy Compression for Exomars (LCE) algorithm on an FPGA by means of high-level synthesis (HSL) in order to shorten the design cycle. Specifically, we use CatapultC HLS tool to obtain a VHDL description of the LCE algorithm from C-language specifications. Two different approaches are followed for HLS: on one hand, introducing the whole C-language description in CatapultC and on the other hand, splitting the C-language description in functional modules to be implemented independently with CatapultC, connecting and controlling them by an RTL description code without HLS. In both cases the goal is to obtain an FPGA implementation. We explain the several changes applied to the original Clanguage source code in order to optimize the results obtained by CatapultC for both approaches. Experimental results show low area occupancy of less than 15% for a SRAM-based Virtex-5 FPGA and a maximum frequency above 80 MHz. Additionally, the LCE compressor was implemented into an RTAX2000S antifuse-based FPGA, showing an area occupancy of 75% and a frequency around 53 MHz. All these serve to demonstrate that the LCE algorithm can be efficiently executed on an FPGA onboard a satellite. A comparison between both implementation approaches is also provided. The performance of the algorithm is finally compared with implementations on other technologies, specifically a graphics processing unit (GPU) and a single-threaded CPU.

Non-Almost Periodicity of Parallel Transports for Homogeneous Connections

International Nuclear Information System (INIS)

Brunnemann, Johannes; Fleischhack, Christian

2012-01-01

Let A be the affine space of all connections in an SU(2) principal fibre bundle over ℝ 3 . The set of homogeneous isotropic connections forms a line l in A. We prove that the parallel transports for general, non-straight paths in the base manifold do not depend almost periodically on l. Consequently, the embedding l ↪ A does not continuously extend to an embedding l-bar ↪ A-bar of the respective compactifications. Here, the Bohr compactification l-bar corresponds to the configuration space of homogeneous isotropic loop quantum cosmology and A-bar to that of loop quantum gravity. Analogous results are given for the anisotropic case.

Celiac disease biodetection using lossy-mode resonances generated in tapered single-mode optical fibers

Science.gov (United States)

Socorro, A. B.; Corres, J. M.; Del Villar, I.; Matias, I. R.; Arregui, F. J.

2014-05-01

This work presents the development and test of an anti-gliadin antibodies biosensor based on lossy mode resonances (LMRs) to detect celiac disease. Several polyelectrolites were used to perform layer-by-layer assembly processes in order to generate the LMR and to fabricate a gliadin-embedded thin-film. The LMR shifted 20 nm when immersed in a 5 ppm anti-gliadin antibodies-PBS solution, what makes this bioprobe suitable for detecting celiac disease. This is the first time, to our knowledge, that LMRs are used to detect celiac disease and these results suppose promising prospects on the use of such phenomena as biological detectors.

Boundary Element Analysis of the Steady-state Response of an Elastic Half-Space to a Moving Force on its Surface

DEFF Research Database (Denmark)

Andersen, Lars; Nielsen, Søren R. K.

2003-01-01

The paper deals with the boundary element method formulation of the steady-state wave propagation through elastic media due to a source moving with constant velocity. The Greens' function for the three-dimensional full-space is formulated in a local frame of reference following the source...... is approximated, but the error which is introduced in this way is insignificant. Numerical examples are given for a moving rectangular load on an elastic half-space. The result from a boundary element code based on the derived Green's function are compared with a semi-analytic solution....

Reflection and transmission of full-vector X-waves normally incident on dielectric half spaces

KAUST Repository

Salem, Mohamed

2011-08-01

The reflection and transmission of full-vector X-Waves incident normally on a planar interface between two lossless dielectric half-spaces are investigated. Full-vector X-Waves are obtained by superimposing transverse electric and magnetic polarization components, which are derived from the scalar X-Wave solution. The analysis of transmission and reflection is carried out via a straightforward but yet effective method: First, the X-Wave is decomposed into vector Bessel beams via the Bessel-Fourier transform. Then, the reflection and transmission coefficients of the beams are obtained in the spectral domain. Finally, the transmitted and reflected X-Waves are obtained via the inverse Bessel-Fourier transform carried out on the X-wave spectrum weighted with the corresponding coefficient. © 2011 IEEE.

Numerical method for solution of transient, homogeneous, equilibrium, two-phase flows in one space dimension

International Nuclear Information System (INIS)

Shin, Y.W.; Wiedermann, A.H.

1979-10-01

A solution method is presented for transient, homogeneous, equilibrium, two-phase flows of a single-component fluid in one space dimension. The method combines a direct finite-difference procedure and the method of characteristics. The finite-difference procedure solves the interior points of the computing domain; the boundary information is provided by a separate procedure based on the characteristics theory. The solution procedure for boundary points requires information in addition to the physical boundary conditions. This additional information is obtained by a new procedure involving integration of characteristics in the hodograph plane. Sample problems involving various combinations of basic boundary types are calculated for two-phase water/steam mixtures and single-phase nitrogen gas, and compared with independent method-of-characteristics solutions using very fine characteristic mesh. In all cases, excellent agreement is demonstrated

A momentum-space formulation without partial wave decomposition for scattering of two spin-half particles

Energy Technology Data Exchange (ETDEWEB)

Fachruddin, Imam, E-mail: imam.fachruddin@sci.ui.ac.id; Salam, Agus [Departemen Fisika, Universitas Indonesia, Depok 16424 (Indonesia)

2016-03-11

A new momentum-space formulation for scattering of two spin-half particles, both either identical or unidentical, is formulated. As basis states the free linear-momentum states are not expanded into the angular-momentum states, the system’s spin states are described by the product of the spin states of the two particles, and the system’s isospin states by the total isospin states of the two particles. We evaluate the Lippmann-Schwinger equations for the T-matrix elements in these basis states. The azimuthal behavior of the potential and of the T-matrix elements leads to a set of coupled integral equations for the T-matrix elements in two variables only, which are the magnitude of the relative momentum and the scattering angle. Some symmetry relations for the potential and the T-matrix elements reduce the number of the integral equations to be solved. A set of six spin operators to express any interaction of two spin-half particles is introduced. We show the spin-averaged differential cross section as being calculated in terms of the solution of the set of the integral equations.

Robust Event-Triggered Energy-to-Peak Filtering for Polytopic Uncertain Systems over Lossy Network with Quantized Measurements

Directory of Open Access Journals (Sweden)

Jidong Wang

2016-01-01

Full Text Available The event-triggered energy-to-peak filtering for polytopic discrete-time linear systems is studied with the consideration of lossy network and quantization error. Because of the communication imperfections from the packet dropout of lossy link, the event-triggered condition used to determine the data release instant at the event generator (EG can not be directly applied to update the filter input at the zero order holder (ZOH when performing filter performance analysis and synthesis. In order to balance such nonuniform time series between the triggered instant of EG and the updated instant of ZOH, two event-triggered conditions are defined, respectively, whereafter a worst-case bound on the number of consecutive packet losses of the transmitted data from EG is given, which marginally guarantees the effectiveness of the filter that will be designed based on the event-triggered updating condition of ZOH. Then, the filter performance analysis conditions are obtained under the assumption that the maximum number of packet losses is allowable for the worst-case bound. In what follows, a two-stage LMI-based alternative optimization approach is proposed to separately design the filter, which reduces the conservatism of the traditional linearization method of filter analysis conditions. Subsequently a codesign algorithm is developed to determine the communication and filter parameters simultaneously. Finally, an illustrative example is provided to verify the validity of the obtained results.

Toward whole-core neutron transport without spatial homogenization

International Nuclear Information System (INIS)

Lewis, E. E.

2009-01-01

Full text of publication follows: A long-term goal of computational reactor physics is the deterministic analysis of power reactor core neutronics without incurring significant discretization errors in the energy, spatial or angular variables. In principle, given large enough parallel configurations with unlimited CPU time and memory, this goal could be achieved using existing three-dimensional neutron transport codes. In practice, however, solving the Boltzmann equation for neutrons over the six-dimensional phase space is made intractable by the nature of neutron cross-sections and the complexity and size of power reactor cores. Tens of thousands of energy groups would be required for faithful cross section representation. Likewise, the numerous material interfaces present in power reactor lattices require exceedingly fine spatial mesh structures; these ubiquitous interfaces preclude effective implementation of adaptive grid, mesh-less methods and related techniques that have been applied so successfully in other areas of engineering science. These challenges notwithstanding, substantial progress continues in the pursuit for more robust deterministic methods for whole-core neutronics analysis. This paper examines the progress over roughly the last decade, emphasizing the space-angle variables and the quest to eliminate errors attributable to spatial homogenization. As prolog we briefly assess 1990's methods used in light water reactor analysis and review the lessons learned from the C5G7 benchmark exercises which were originated in 1999 to appraise the ability of transport codes to perform core calculations without homogenization. We proceed by examining progress over the last decade much of which falls into three areas. These may be broadly characterized as reduced homogenization, dynamic homogenization and planar-axial synthesis. In the first, homogenization in three-dimensional calculations is reduced from the fuel assembly to the pin-cell level. In the second

Surface Displacement Field of a Coated Elastic Half-Space Under the Influence of a Moving Distributional Load

Directory of Open Access Journals (Sweden)

Onur Şahin

2017-04-01

Full Text Available An analysis of the distributed moving load along the surface of a coated half space is presented. The formulation of the problem depends on the hyperbolic-elliptic asymptotic model developed earlier by the authors. The integral solution of the longitudinal and transverse displacements along the surface for the sub and super-Rayleigh cases are obtained by using the uniform stationary phase method. Numerical comparisons of the exact and asymptotic solutions of the longitudinal displacement are illustrated for the certain cross-sections of the profile.

Reflection of Plane Waves in Generalized Thermoelastic Half Space under the Action of Uniform Magnetic Field

Directory of Open Access Journals (Sweden)

Narottam Maity

2016-01-01

Full Text Available Reflection of longitudinal displacement waves in a generalized thermoelastic half space under the action of uniform magnetic field has been investigated. The magnetic field is applied in such a direction that the problem can be considered as a two-dimensional one. The discussion is based on the three theories of generalized thermoelasticity: Lord-Shulman (L-S, Green-Lindsay (G-L, and Green-Naghdi (G-N with energy dissipation. We compute the possible wave velocities for different models. Amplitude ratios have been presented. The effects of magnetic field on various subjects of interest are discussed and shown graphically.

Time travel in the homogeneous Som-Raychaudhuri Universe

International Nuclear Information System (INIS)

Paiva, F.M.; Reboucas, M.J.; Teixeira, A.F.F.

1987-01-01

Properties of the rotating Som-Raychaudhuri homogeneous space-time are investigated: time-like and null geodesics, causality features, horizons and invariant characterization. An integral representation of its five isometries is also discussed. (author) [pt

Implications for space radiation environment models from CREAM and CREDO measurements over half a solar cycle

International Nuclear Information System (INIS)

Dyer, C.S.; Truscott, P.R.; Peerless, C.L.; Watson, C.J.; Evans, H.E.; Knight, P.; Cosby, M.; Underwood, C.; Cousins, T.; Noulty, R.; Maag, C.

1999-01-01

Flight data obtained between 1990 and 1997 from the Cosmic Radiation Environment Monitors CREAM and CREDO carried on UoSAT-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) provide coverage over half a solar cycle. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor of three increase at high latitudes and the latter a general increase accompanied by a north-westward drift. Comparison of particle fluxes and linear energy transfer (LET) spectra is made with improved environment and radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatment of locally produced secondary particles. Solar-particle events during this time period have LET spectra significantly below the October 1989 event which has been proposed as a worst case model

Multiscale models in mechano and tumor biology modeling, homogenization, and applications

CERN Document Server

Penta, Raimondo; Lang, Jens

2017-01-01

This book presents and discusses the state of the art and future perspectives in mathematical modeling and homogenization techniques with the focus on addressing key physiological issues in the context of multiphase healthy and malignant biological materials. The highly interdisciplinary content brings together contributions from scientists with complementary areas of expertise, such as pure and applied mathematicians, engineers, and biophysicists. The book also features the lecture notes from a half-day introductory course on asymptotic homogenization. These notes are suitable for undergraduate mathematics or physics students, while the other chapters are aimed at graduate students and researchers.

Selection of suitable prodrug candidates for in vivo studies via in vitro studies; the correlation of prodrug stability in between cell culture homogenates and human tissue homogenates.

Science.gov (United States)

Tsume, Yasuhiro; Amidon, Gordon L

2012-01-01

To determine the correlations/discrepancies of drug stabilities between in the homogenates of human culture cells and of human tissues. Amino acid/dipeptide monoester prodrugs of floxuridine were chosen as the model drugs. The stabilities (half-lives) of floxuridine prodrugs in human tissues (pancreas, liver, and small intestine) homogenates were obtained and compared with ones in cell culture homogenates (AcPC-1, Capan-2, and Caco-2 cells) as well as human liver microsomes. The correlations of prodrug stability in human small bowel tissue homogenate vs. Caco-2 cell homogenate, human liver tissue homogenate vs. human liver microsomes, and human pancreatic tissue homogenate vs. pancreatic cell, AsPC-1 and Capan-2, homogenates were examined. The stabilities of floxuridine prodrugs in human small bowel homogenate exhibited the great correlation to ones in Caco-2 cell homogenate (slope = 1.0-1.3, r2 = 0.79-0.98). The stability of those prodrugs in human pancreas tissue homogenate also exhibited the good correlations to ones in AsPC-1 and Capan-2 cells homogenates (slope = 0.5-0.8, r2 = 0.58-0.79). However, the correlations of prodrug stabilities between in human liver tissue homogenates and in human liver microsomes were weaker than others (slope = 1.3-1.9, r2 = 0.07-0.24). The correlations of drug stabilities in cultured cell homogenates and in human tissue homogenates were compared. Those results exhibited wide range of correlations between in cell homogenate and in human tissue homogenate (r2 = 0.07 - 0.98). Those in vitro studies in cell homogenates would be good tools to predict drug stabilities in vivo and to select drug candidates for further developments. In the series of experiments, 5'-O-D-valyl-floxuridine and 5'-O-L-phenylalanyl-L-tyrosyl-floxuridine would be selected as candidates of oral drug targeting delivery for cancer chemotherapy due to their relatively good stabilities compared to other tested prodrugs.

Excitation of the Uller-Zenneck electromagnetic surface waves in the prism-coupled configuration

Science.gov (United States)

Rasheed, Mehran; Faryad, Muhammad

2017-08-01

A configuration to excite the Uller-Zenneck surface electromagnetic waves at the planar interfaces of homogeneous and isotropic dielectric materials is proposed and theoretically analyzed. The Uller-Zenneck waves are surface waves that can exist at the planar interface of two dissimilar dielectric materials of which at least one is a lossy dielectric material. In this paper, a slab of a lossy dielectric material was taken with lossless dielectric materials on both sides. A canonical boundary-value problem was set up and solved to find the possible Uller-Zenneck waves and waveguide modes. The Uller-Zenneck waves guided by the slab of the lossy dielectric material were found to be either symmetric or antisymmetric and transmuted into waveguide modes when the thickness of that slab was increased. A prism-coupled configuration was then successfully devised to excite the Uller-Zenneck waves. The results showed that the Uller-Zenneck waves are excited at the same angle of incidence for any thickness of the slab of the lossy dielectric material, whereas the waveguide modes can be excited when the slab is sufficiently thick. The excitation of Uller-Zenneck waves at the planar interfaces with homogeneous and all-dielectric materials can usher in new avenues for the applications for electromagnetic surface waves.

MFT homogeneity study at TNX: Final report on the low weight percent solids concentration

International Nuclear Information System (INIS)

Jenkins, W.J.

1993-01-01

A statistical design and analysis of both elemental analyses and weight percent solids analyses data was utilized to evaluate the MFT homogeneity at low heel levels and low agitator speed at both high and low solids feed concentrations. The homogeneity was also evaluated at both low and high agitator speed at the 6000+ gallons static level. The dynamic level portion of the test simulated feeding the Melter from the MFT to evaluate the uniformity of the solids slurry composition (Frit-PHA-Sludge) entering the melter from the MFT. This final report provides the results and conclusions from the second half of the study, the low weight percent solids concentration portion, as well as a comparison with the results from the first half of the study, the high weight percent solids portion

Eesti Ajaloomuuseumi, Maarjamäe lossi tallihoone renoveerimine = Renovation of the Estonian History Museum's Maarjamäe palace stables / Jaak Huimerind, Tarmo Piirmets ; kommenteerinud Kaido Kivi

Index Scriptorium Estoniae

Huimerind, Jaak, 1957-

2015-01-01

Eesti Ajaloomuuseumi Maarjamäe lossi renoveeritud tallihoone Tallinnas Pirita tee 66, valminud 2014. Arhitekt Jaak Huimerind (Studio Paralleel OÜ), sisearhitekt ja näituse kujundaja Tarmo Piirmets (Pink OÜ). Eesti Kultuurkapitali Arhitektuuri sihtkapitali renoveerimispreemia 2014

A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL).

Science.gov (United States)

Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

2015-08-10

In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds.

A Scalable Context-Aware Objective Function (SCAOF of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL

Directory of Open Access Journals (Sweden)

Yibo Chen

2015-08-01

Full Text Available In recent years, IoT (Internet of Things technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL, which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds.

Static deformation due to a long buried dip-slip fault in an isotropic

Indian Academy of Sciences (India)

Closed-form analytical expressions for the displacements and the stresses at any point of a two-phase medium consisting of a homogeneous, isotropic, perfectly elastic half-space in welded contact with a homogeneous, orthotropic, perfectly elastic half-space due to a dip-slip fault of finite width located at an arbitrary ...

Spontaneous radiation of a chiral molecule located near a half-space of a bi-isotropic material

Science.gov (United States)

Guzatov, D. V.; Klimov, V. V.; Poprukailo, N. S.

2013-04-01

Analytical expressions for the rate of spontaneous emission from a chiral (optically active) molecule located near a half-space occupied by a chiral (bi-isotropic) material have been obtained and analyzed in detail. It is established that the rates of spontaneous emission from the "right" and "left" enantiomers of molecules occurring near the chiral medium may significantly differ in cases of chiral materials with (i) both negative dielectric permittivity and magnetic permeability (DNG metamaterial) and (ii) negative permeability and positive permittivity (MNG metamaterial). Based on this phenomenon, DMG and MNG metamaterials can be used to create devices capable of separating right and left enantiomers in racemic mixtures.

Spontaneous radiation of a chiral molecule located near a half-space of a bi-isotropic material

Energy Technology Data Exchange (ETDEWEB)

Guzatov, D. V., E-mail: vklimov@sci.lebedev.ru [Yanka Kupala Grodno State University (Belarus); Klimov, V. V., E-mail: klimov256@gmail.com [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Poprukailo, N. S. [Yanka Kupala Grodno State University (Belarus)

2013-04-15

Analytical expressions for the rate of spontaneous emission from a chiral (optically active) molecule located near a half-space occupied by a chiral (bi-isotropic) material have been obtained and analyzed in detail. It is established that the rates of spontaneous emission from the 'right' and 'left' enantiomers of molecules occurring near the chiral medium may significantly differ in cases of chiral materials with (i) both negative dielectric permittivity and magnetic permeability (DNG metamaterial) and (ii) negative permeability and positive permittivity (MNG metamaterial). Based on this phenomenon, DMG and MNG metamaterials can be used to create devices capable of separating right and left enantiomers in racemic mixtures.

Spontaneous radiation of a chiral molecule located near a half-space of a bi-isotropic material

International Nuclear Information System (INIS)

Guzatov, D. V.; Klimov, V. V.; Poprukailo, N. S.

2013-01-01

Analytical expressions for the rate of spontaneous emission from a chiral (optically active) molecule located near a half-space occupied by a chiral (bi-isotropic) material have been obtained and analyzed in detail. It is established that the rates of spontaneous emission from the “right” and “left” enantiomers of molecules occurring near the chiral medium may significantly differ in cases of chiral materials with (i) both negative dielectric permittivity and magnetic permeability (DNG metamaterial) and (ii) negative permeability and positive permittivity (MNG metamaterial). Based on this phenomenon, DMG and MNG metamaterials can be used to create devices capable of separating right and left enantiomers in racemic mixtures.

An analysis of the Rose's shim method for improvement of magnetic field homogeneity

International Nuclear Information System (INIS)

Ban, Etsuo

1981-01-01

Well known Rose's method has been applied to the magnets requiring high homogeneity (e.g. for magnetic resonance). The analysis of the Rose's shim is based on the conformal representation, and it is applicable to the poles of any form obtained by the combination of polygons. It provides rims for the magnetic poles of 90 deg edges. In this paper, the solution is determined by the elliptic function to give the magnetic field at any point in the space, directly integrating by the Schwarz-Christoffel transformation, instead of the approximate numerical integration employed by Rose, and compared with the example having applied it to a cylindrical pole. For the conditions of Rose's optimum correction, the exact solution is given as the case that the parameters of Jacobi's third kind elliptic function are equal to a half of first kind perfect elliptic integral. Since Rose depended on the approximate numerical integration, Rose's diagram showed a little insufficient correction. It was found that the pole shape giving excess correction of 10 -4 or so produced a good result for the cylindrical magnetic pole having the ratio of pole diameter to gap length of 2.5. In order to obtain the correction by which the change in homogeneity is small up to considerably intense field, the pole edges are required to be of curved surfaces. (Wakatsuki, Y.)

THE STRESS-STRAIN STATE OF ELASTIC HALF-SPACE FROM RUNNING LINEAR LOAD ACTING ON THE LIMITED AND UNLIMITED EXTENT OVER ITS SURFACE

Directory of Open Access Journals (Sweden)

I. K. Badalakha

2009-02-01

Full Text Available The article shows the result of solving the problem of stress-strain state of an elastic half-space because of the load action that uniformly distributed over the line, with the use of untraditional linear dependence of deformations on stressed state that is different from the generalized Hooke’s law.

Half-space problem of unsteady evaporation and condensation of polyatomic gas

Science.gov (United States)

Inaba, Masashi; Yano, Takeru

2016-11-01

On the basis of polyatomic version of the ellipsoidal-statistical Bhatnager-Gross-Krook (ES-BGK) model, we consider time-periodic gas flows in a semi-infinite expanse of an initially equilibrium polyatomic gas (methanol) bounded by its planar condensed phase. The kinetic boundary condition at the vapor-liquid interface is assumed to be the complete condensation condition with periodically time-varying macroscopic variables (temperature, saturated vapor density and velocity of the interface), and the boundary condition at infinity is the local equilibrium distribution function. The time scale of variation of macroscopic variables is assumed to be much larger than the mean free time of gas molecules, and the variations of those from a reference state are assumed to be sufficiently small. We numerically investigate thus formulated time-dependent half-space problem for the polyatomic version of linearized ES-BGK model equation with the finite difference method for the case of the Strouhal number Sh=0.01 and 0.1. It is shown that the amplitude of the mass flux at the interface is the maximum, and the phase difference in time between the mass flux and v∞ - vℓ (v∞: vapor velocity at infinity, vℓ: velocity of the vapor-liquid interface) is the minimum absolute value, when the phase difference in time between the liquid surface temperature (the saturated vapor density) and the velocity of interface is close to zero.

Stegano-Crypto Hiding Encrypted Data in Encrypted Image Using Advanced Encryption Standard and Lossy Algorithm

Directory of Open Access Journals (Sweden)

Ari Shawakat Tahir

2015-12-01

Full Text Available The Steganography is an art and science of hiding information by embedding messages within other, seemingly harmless messages and lots of researches are working in it. Proposed system is using AES Algorithm and Lossy technique to overcome the limitation of previous work and increasing the process’s speed. The sender uses AES Algorithm to encrypt message and image, then using LSB technique to hide encrypted data in encrypted message. The receive get the original data using the keys that had been used in encryption process. The proposed system has been implemented in NetBeans 7.3 software uses image and data in different size to find the system’s speed.

On the Far-Zone Electromagnetic Field of a Horizontal Electric Dipole Over an Imperfectly Conducting Half-Space With Extensions to Plasmonics

Science.gov (United States)

Michalski, Krzysztof A.; Lin, Hung-I.

2018-01-01

Second-order asymptotic formulas for the electromagnetic fields of a horizontal electric dipole over an imperfectly conducting half-space are derived using the modified saddle-point method. Application examples are presented for ordinary and plasmonic media, and the accuracy of the new formulation is assessed by comparisons with two alternative state-of-the-art theories and with the rigorous results of numerical integration.

Casimir friction between polarizable particle and half-space with radiation damping at zero temperature

International Nuclear Information System (INIS)

Høye, J S; I Brevik; Milton, K A

2015-01-01

Casimir friction between a polarizable particle and a semi-infinite space is a delicate physical phenomenon, as it concerns the interaction between a microscopic quantum particle and a semi-infinite reservoir. Not unexpectedly, results obtained in the past about the friction force obtained via different routes are sometimes, at least apparently, wildly different from each other. Recently, we considered the Casimir friction force for two dielectric semi-infinite plates moving parallel to each other Høye and Brevik (2014 Eur. Phys. J. D 68 61), and managed to get essential agreement with results obtained by Pendry (1997 J. Phys.: Condens. Matter 9 10301), Volokitin and Persson (2007 Rev. Mod. Phys. 79 1291), and Barton (2011 New J. Phys. 13 043023; 2011 J. Phys.: Condens. Matter 23 335004). Our method was based upon use of the Kubo formalism. In the present paper we focus on the interaction between a polarizable particle and a dielectric half-space again, and calculate the friction force using the same basic method as before. The new ingredient in the present analysis is that we take into account radiative damping, and derive the modifications thereof. Some comparisons are also made with works from others. Essential agreement with the results of Intravaia, Behunin, and Dalvit can also be achieved using the modification of the atomic polarizability by the metallic plate. (paper)

Graphene Oxide in Lossy Mode Resonance-Based Optical Fiber Sensors for Ethanol Detection

Directory of Open Access Journals (Sweden)

Miguel Hernaez

2017-12-01

Full Text Available The influence of graphene oxide (GO over the features of an optical fiber ethanol sensor based on lossy mode resonances (LMR has been studied in this work. Four different sensors were built with this aim, each comprising a multimode optical fiber core fragment coated with a SnO2 thin film. Layer by layer (LbL coatings made of 1, 2 and 4 bilayers of polyethyleneimine (PEI and graphene oxide were deposited onto three of these devices and their behavior as aqueous ethanol sensors was characterized and compared with the sensor without GO. The sensors with GO showed much better performance with a maximum sensitivity enhancement of 176% with respect to the sensor without GO. To our knowledge, this is the first time that GO has been used to make an optical fiber sensor based on LMR.

Graphene Oxide in Lossy Mode Resonance-Based Optical Fiber Sensors for Ethanol Detection.

Science.gov (United States)

Hernaez, Miguel; Mayes, Andrew G; Melendi-Espina, Sonia

2017-12-27

The influence of graphene oxide (GO) over the features of an optical fiber ethanol sensor based on lossy mode resonances (LMR) has been studied in this work. Four different sensors were built with this aim, each comprising a multimode optical fiber core fragment coated with a SnO₂ thin film. Layer by layer (LbL) coatings made of 1, 2 and 4 bilayers of polyethyleneimine (PEI) and graphene oxide were deposited onto three of these devices and their behavior as aqueous ethanol sensors was characterized and compared with the sensor without GO. The sensors with GO showed much better performance with a maximum sensitivity enhancement of 176% with respect to the sensor without GO. To our knowledge, this is the first time that GO has been used to make an optical fiber sensor based on LMR.

Particle in the magnetic field: 2D Riemann spherical space and complex analogue of the Poincare half-plane

International Nuclear Information System (INIS)

Red'kov, V.M.; Ovsiyuk, E.M.; Ishkhanyan, A.M.

2013-01-01

The Schrodinger particle on the background of the 2D space of the constant positive curvature S 2 , a sphere in the 3D Euclidean space, is considered in the external magnetic field. By analogy with the case of the hyperbolic Lobachevsky plane H 2 , where quasi-Cartesian coordinates exist with the realization of H 2 as the Poincare half-plane, a specific system of quasi-Cartesian coordinates (x, y) in S 2 is introduced. It turns out that it is possible only if the two coordinates are complex and obey an additional restriction in order to present a real 2D space. The Schrodinger equation is solved using the method of separation of the variables in the both coordinate systems, cylindrical and quasi-Cartesian, the energy spectrum is the same. For parametrization of the space S 2 , one can use the coordinates (x, x*) or (y, y*), however, in this case the separability of the variables in the wave functions is lost. Constructed solutions may be of interest for describing charged particles in magnetic fields in the context of cosmological models, and for simulating the behavior of the particles in a specific field-configuration in the nano-physics. (authors)

Homogeneous collapsing star: Tensor and vector harmonics for matter and field asymmetries

International Nuclear Information System (INIS)

Gerlach, U.H.; Sengupta, U.K.

1978-01-01

For the space-time of the interior of a homogeneous collapsing star complete sets of orthogonal vector and tensor harmonics are presented. Their relationship to the set of vector and tensor harmonics for a generic spherically symmetric space-time is exhibited

Delay reduction in lossy intermittent feedback for generalized instantly decodable network coding

KAUST Repository

Douik, Ahmed S.

2013-10-01

In this paper, we study the effect of lossy intermittent feedback loss events on the multicast decoding delay performance of generalized instantly decodable network coding. These feedback loss events create uncertainty at the sender about the reception statues of different receivers and thus uncertainty to accurately determine subsequent instantly decodable coded packets. To solve this problem, we first identify the different possibilities of uncertain packets at the sender and their probabilities. We then derive the expression of the mean decoding delay. We formulate the Generalized Instantly Decodable Network Coding (G-IDNC) minimum decoding delay problem as a maximum weight clique problem. Since finding the optimal solution is NP-hard, we design a variant of the algorithm employed in [1]. Our algorithm is compared to the two blind graph update proposed in [2] through extensive simulations. Results show that our algorithm outperforms the blind approaches in all the situations and achieves a tolerable degradation, against the perfect feedback, for large feedback loss period. © 2013 IEEE.

Delay reduction in lossy intermittent feedback for generalized instantly decodable network coding

KAUST Repository

Douik, Ahmed S.; Sorour, Sameh; Alouini, Mohamed-Slim; Ai-Naffouri, Tareq Y.

2013-01-01

In this paper, we study the effect of lossy intermittent feedback loss events on the multicast decoding delay performance of generalized instantly decodable network coding. These feedback loss events create uncertainty at the sender about the reception statues of different receivers and thus uncertainty to accurately determine subsequent instantly decodable coded packets. To solve this problem, we first identify the different possibilities of uncertain packets at the sender and their probabilities. We then derive the expression of the mean decoding delay. We formulate the Generalized Instantly Decodable Network Coding (G-IDNC) minimum decoding delay problem as a maximum weight clique problem. Since finding the optimal solution is NP-hard, we design a variant of the algorithm employed in [1]. Our algorithm is compared to the two blind graph update proposed in [2] through extensive simulations. Results show that our algorithm outperforms the blind approaches in all the situations and achieves a tolerable degradation, against the perfect feedback, for large feedback loss period. © 2013 IEEE.

The coadjoint orbit spaces of Diff(S1) and Teichmueller spaces

International Nuclear Information System (INIS)

Nag, S.; Verjovsky, A.

1989-09-01

Precisely two of the homogeneous spaces that appear as coadjoint orbits of the group of string reparametrizations (Diff (S 1 )) carry in a natural way the structure of infinite dimensional, holomorphically homogeneous complex analytic Kaehler manifolds. These are N = Diff (S 1 )/Rot (S 1 ) and M = Diff (S 1 )/Moeb (S 1 ). Note that N is a holomorphic disc fiber space over M. Now, M can be naturally considered as embedded in the classical universal Teichmueller space T(1), simply by noting that a diffeomorphism of S 1 is a quasisymmetric homeomorphism. T(1) is itself a homomorphically homogeneous complex Banach manifold. We prove in the first part of the paper that the inclusion of M in T(1) is complex analytic. In the latter portion of this paper it is shown that the unique homogeneous Kaehler metric carried by M = Diff (S 1 )/SL(2, R) induces precisely the Weil-Petersson metric on the Teichmueller space. This is via our identification of M as a holomorphic submanifold of universal Teichmueller space. Now recall that every Teichmueller space T(G) of finite or infinite dimension is contained canonically and holomorphically within T(1). Our computations allow us also to prove that every T(G), G any infinite Fuchsian group, projects out of M transversely. This last assertion is related to the ''fractal'' nature of G-invariant quasicircles, and to Mostow rigidity on the line. Our results thus connect the loop space approach to bosonic string theory with the sumover moduli (Polyakov path integral) approach. (author). 21 refs

The use of ZFP lossy floating point data compression in tornado-resolving thunderstorm simulations

Science.gov (United States)

Orf, L.

2017-12-01

In the field of atmospheric science, numerical models are used to produce forecasts of weather and climate and serve as virtual laboratories for scientists studying atmospheric phenomena. In both operational and research arenas, atmospheric simulations exploiting modern supercomputing hardware can produce a tremendous amount of data. During model execution, the transfer of floating point data from memory to the file system is often a significant bottleneck where I/O can dominate wallclock time. One way to reduce the I/O footprint is to compress the floating point data, which reduces amount of data saved to the file system. In this presentation we introduce LOFS, a file system developed specifically for use in three-dimensional numerical weather models that are run on massively parallel supercomputers. LOFS utilizes the core (in-memory buffered) HDF5 driver and includes compression options including ZFP, a lossy floating point data compression algorithm. ZFP offers several mechanisms for specifying the amount of lossy compression to be applied to floating point data, including the ability to specify the maximum absolute error allowed in each compressed 3D array. We explore different maximum error tolerances in a tornado-resolving supercell thunderstorm simulation for model variables including cloud and precipitation, temperature, wind velocity and vorticity magnitude. We find that average compression ratios exceeding 20:1 in scientifically interesting regions of the simulation domain produce visually identical results to uncompressed data in visualizations and plots. Since LOFS splits the model domain across many files, compression ratios for a given error tolerance can be compared across different locations within the model domain. We find that regions of high spatial variability (which tend to be where scientifically interesting things are occurring) show the lowest compression ratios, whereas regions of the domain with little spatial variability compress

Lattice Boltzmann model for three-dimensional decaying homogeneous isotropic turbulence

International Nuclear Information System (INIS)

Xu Hui; Tao Wenquan; Zhang Yan

2009-01-01

We implement a lattice Boltzmann method (LBM) for decaying homogeneous isotropic turbulence based on an analogous Galerkin filter and focus on the fundamental statistical isotropic property. This regularized method is constructed based on orthogonal Hermite polynomial space. For decaying homogeneous isotropic turbulence, this regularized method can simulate the isotropic property very well. Numerical studies demonstrate that the novel regularized LBM is a promising approximation of turbulent fluid flows, which paves the way for coupling various turbulent models with LBM

Space-Charge-Limited Emission Models for Particle Simulation

Science.gov (United States)

Verboncoeur, J. P.; Cartwright, K. L.; Murphy, T.

2004-11-01

Space-charge-limited (SCL) emission of electrons from various materials is a common method of generating the high current beams required to drive high power microwave (HPM) sources. In the SCL emission process, sufficient space charge is extracted from a surface, often of complicated geometry, to drive the electric field normal to the surface close to zero. The emitted current is highly dominated by space charge effects as well as ambient fields near the surface. In this work, we consider computational models for the macroscopic SCL emission process including application of Gauss's law and the Child-Langmuir law for space-charge-limited emission. Models are described for ideal conductors, lossy conductors, and dielectrics. Also considered is the discretization of these models, and the implications for the emission physics. Previous work on primary and dual-cell emission models [Watrous et al., Phys. Plasmas 8, 289-296 (2001)] is reexamined, and aspects of the performance, including fidelity and noise properties, are improved. Models for one-dimensional diodes are considered, as well as multidimensional emitting surfaces, which include corners and transverse fields.

The energy spectrum of electromagnetic normal modes in dissipative media: modes between two metal half spaces

International Nuclear Information System (INIS)

Sernelius, Bo E

2008-01-01

The energy spectrum of electromagnetic normal modes plays a central role in the theory of the van der Waals and Casimir interaction. Here we study the modes in connection with the van der Waals interaction between two metal half spaces. Neglecting dissipation leads to distinct normal modes with real-valued frequencies. Including dissipation seems to have the effect that these distinct modes move away from the real axis into the complex frequency plane. The summation of the zero-point energies of these modes render a complex-valued result. Using the contour integration, resulting from the use of the generalized argument principle, gives a real-valued and different result. We resolve this contradiction and show that the spectrum of true normal modes forms a continuum with real frequencies

Low-gravity homogenization and solidification of aluminum antimonide. [Apollo-Soyuz test project

Science.gov (United States)

Ang, C.-Y.; Lacy, L. L.

1976-01-01

The III-V semiconducting compound AlSb shows promise as a highly efficient solar cell material, but it has not been commercially exploited because of difficulties in compound synthesis. Liquid state homogenization and solidification of AlSb were carried out in the Apollo-Soyuz Test Project Experiment MA-044 in the hope that compositional homogeneity would be improved by negating the large density difference between the two constituents. Post-flight analysis and comparative characterization of the space-processed and ground-processed samples indicate that there are major homogeneity improvements in the low-gravity solidified material.

The Half-Half Plot

NARCIS (Netherlands)

Einmahl, J.H.J.; Gantner, M.

2009-01-01

The Half-Half (HH) plot is a new graphical method to investigate qualitatively the shape of a regression curve. The empirical HH-plot counts observations in the lower and upper quarter of a strip that moves horizontally over the scatter plot. The plot displays jumps clearly and reveals further

The half-half plot

NARCIS (Netherlands)

Einmahl, J.H.J.; Gantner, M.

2012-01-01

The Half-Half (HH) plot is a new graphical method to investigate qualitatively the shape of a regression curve. The empirical HH-plot counts observations in the lower and upper quarter of a strip that moves horizontally over the scatterplot. The plot displays jumps clearly and reveals further

The relationship between continuum homogeneity and statistical homogeneity in cosmology

International Nuclear Information System (INIS)

Stoeger, W.R.; Ellis, G.F.R.; Hellaby, C.

1987-01-01

Although the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) Universe models are based on the concept that the Universe is spatially homogeneous, up to the present time no definition of this concept has been proposed that could in principle be tested by observation. Such a definition is here proposed, based on a simple spatial averaging procedure, which relates observable properties of the Universe to the continuum homogeneity idea that underlies the FLRW models. It turns out that the statistical homogeneity often used to describe the distribution of matter on a large scale does not imply spatial homogeneity according to this definition, and so cannot be simply related to a FLRW Universe model. Values are proposed for the homogeneity parameter and length scale of homogeneity of the Universe. (author)

Diffraction of love waves by two staggered perfectly weak half-planes

International Nuclear Information System (INIS)

Asghar, S.; Zaman, F.D.; Sajida Asghar

1989-01-01

Love wave travelling in a layer of uniform thickness overlying a half-space is assumed to be incident on two parallel but staggered perfectly weak half-planes lying in the upper layer. The diffracted fields is calculated using the modified Wiener-Hopf technique and contour integration method. The diffracted waves satisfy the dispersion relations appropriate to different regions formed by the perfectly weak half-planes

Distributions asymptotically homogeneous along the trajectories determined by one-parameter groups

International Nuclear Information System (INIS)

Drozhzhinov, Yurii N; Zav'yalov, Boris I

2012-01-01

We give a complete description of distributions that are asymptotically homogeneous (including the case of critical index of the asymptotic scale) along the trajectories determined by continuous multiplicative one-parameter transformation groups such that the real parts of all eigenvalues of the infinitesimal matrix are positive. To do this, we introduce and study special spaces of distributions. As an application of our results, we describe distributions that are homogeneous along such groups.

Mechanical Homogenization Increases Bacterial Homogeneity in Sputum

Science.gov (United States)

Stokell, Joshua R.; Khan, Ammad

2014-01-01

Sputum obtained from patients with cystic fibrosis (CF) is highly viscous and often heterogeneous in bacterial distribution. Adding dithiothreitol (DTT) is the standard method for liquefaction prior to processing sputum for molecular detection assays. To determine if DTT treatment homogenizes the bacterial distribution within sputum, we measured the difference in mean total bacterial abundance and abundance of Burkholderia multivorans between aliquots of DTT-treated sputum samples with and without a mechanical homogenization (MH) step using a high-speed dispersing element. Additionally, we measured the effect of MH on bacterial abundance. We found a significant difference between the mean bacterial abundances in aliquots that were subjected to only DTT treatment and those of the aliquots which included an MH step (all bacteria, P = 0.04; B. multivorans, P = 0.05). There was no significant effect of MH on bacterial abundance in sputum. Although our results are from a single CF patient, they indicate that mechanical homogenization increases the homogeneity of bacteria in sputum. PMID:24759710

Transient computational homogenization for heterogeneous materials under dynamic excitation

NARCIS (Netherlands)

Pham, N.K.H.; Kouznetsova, V.; Geers, M.G.D.

2013-01-01

This paper presents a novel transient computational homogenization procedure that is suitable for the modelling of the evolution in space and in time of materials with non-steady state microstructure, such as metamaterials. This transient scheme is an extension of the classical (first-order)

Industrializing the near-earth asteroids: Speculations on human activities in space in the latter half of the 21st century

Science.gov (United States)

Sercel, Joel C.

1990-01-01

The use of solar system resources for human industry can be viewed as a natural extension of the continual growth of our species' habitat. Motivations for human activities in space can be discussed in terms of five distinct areas: (1) information processing and collection; (2) materials processing; (3) energy production to meet terrestrial power needs; (4) the use of extraterrestrial materials; and (5) disaster avoidance. When considering 21st-Century activities in space, each of these basic motivations must be treated in light of issues likely to be relevant to the 21st-Century earth. Many of the problems facing 21st-Century earth may stem from the need to maintain the world population of 8 to 10 billion people as is projected from expected growth rates. These problems are likely to include managing the impact of industrial processes on the terrestrial biosphere while providing adequate energy production and material goods for the growing population. The most important human activities in space in the latter half of the 21st Century may be associated with harnessing the resources of the near-earth asteroids for industrial processes. These above topics are discussed with an emphasis on space industrialization.

Performance evaluation of a lossy transmission lines based diode detector at cryogenic temperature.

Science.gov (United States)

Villa, E; Aja, B; de la Fuente, L; Artal, E

2016-01-01

This work is focused on the design, fabrication, and performance analysis of a square-law Schottky diode detector based on lossy transmission lines working under cryogenic temperature (15 K). The design analysis of a microwave detector, based on a planar gallium-arsenide low effective Schottky barrier height diode, is reported, which is aimed for achieving large input return loss as well as flat sensitivity versus frequency. The designed circuit demonstrates good sensitivity, as well as a good return loss in a wide bandwidth at Ka-band, at both room (300 K) and cryogenic (15 K) temperatures. A good sensitivity of 1000 mV/mW and input return loss better than 12 dB have been achieved when it works as a zero-bias Schottky diode detector at room temperature, increasing the sensitivity up to a minimum of 2200 mV/mW, with the need of a DC bias current, at cryogenic temperature.

Role of Ability and Extroversion in Concept Attainment of Individuals Trained in Heterogeneous or Homogeneous Personality Groups

Science.gov (United States)

Lemke, E. A.; And Others

1974-01-01

Subjects stratified by ability and extroversion initially achieved concept attainment in homogeneous (all introverts or all extroverts) or heterogeneous (one-half of the members extroverts) personality groups. Concepts were attained individually in a subsequent transfer stage. (Authors/JA)

Inverse scattering of a layered and dispersionless dielectric half-space - 1. reflection data from plane waves at normal incidence

International Nuclear Information System (INIS)

Coen, S.

1981-01-01

The theory given by Moses and deRidder is modified so that the derivative of the solution of the Gelfand-Levitan integral equation is not required. Based on this modification, a numerical procedure is developed which approximately constructs the dielectric profile of the layered half-space from the impulse response. Moreover, an inverse scattering theory is developed for a Goupillaud-type dielectric medium, and a fast numerical procedure based on the Berryman and Greene algorithm is presented. The performance of the numerical algorithms is examined by applying them to pecise and imprecise artificial impulse response data. 11 refs

Diffraction of love waves by two parallel perfectly weak half planes

International Nuclear Information System (INIS)

Asghar, S.; Zaman, F.D.; Ayub, M.

1986-04-01

We consider the diffraction of Love waves by two parallel perfectly weak half planes in a layer overlying a half space. The problem is formulated in terms of the Wiener-Hopf equations in the transformed plane. The transmitted waves are then calculated using the Wiener-Hopf procedure and inverse transforms. (author)

Interaction between a punch and an arbitrary crack or inclusion in a transversely isotropic half-space

Science.gov (United States)

Fabrikant, I.; Karapetian, E.; Kalinin, S. V.

2018-02-01

We consider the problem of an arbitrary shaped rigid punch pressed against the boundary of a transversely isotropic half-space and interacting with an arbitrary flat crack or inclusion, located in the plane parallel to the boundary. The set of governing integral equations is derived for the most general conditions, namely the presence of both normal and tangential stresses under the punch, as well as general loading of the crack faces. In order to verify correctness of the derivations, two different methods were used to obtain governing integral equations: generalized method of images and utilization of the reciprocal theorem. Both methods gave the same results. Axisymmetric coaxial case of interaction between a rigid inclusion and a flat circular punch both centered along the z-axis is considered as an illustrative example. Most of the final results are presented in terms of elementary functions.

Endomorphisms on half-sided modular inclusions

International Nuclear Information System (INIS)

Svegstrup, Rolf Dyre

2006-01-01

In algebraic quantum field theory we consider nets of von Neumann algebras indexed over regions of the space time. Wiesbrock [''Conformal quantum field theory and half-sided modular inclusions of von Neumann algebras,'' Commun. Math. Phys. 158, 537-543 (1993)] has shown that strongly additive nets of von Neumann algebras on the circle are in correspondence with standard half-sided modular inclusions. We show that a finite index endomorphism on a half-sided modular inclusion extends to a finite index endomorphism on the corresponding net of von Neumann algebras on the circle. Moreover, we present another approach to encoding endomorphisms on nets of von Neumann algebras on the circle into half-sided modular inclusions. There is a natural way to associate a weight to a Moebius covariant endomorphism. The properties of this weight have been studied by Bertozzini et al. [''Covariant sectors with infinite dimension and positivity of the energy,'' Commun. Math. Phys. 193, 471-492 (1998)]. In this paper we show the converse, namely, how to associate a Moebius covariant endomorphism to a given weight under certain assumptions, thus obtaining a correspondence between a class of weights on a half-sided modular inclusion and a subclass of the Moebius covariant endomorphisms on the associated net of von Neumann algebras. This allows us to treat Moebius covariant endomorphisms in terms of weights on half-sided modular inclusions. As our aim is to provide a framework for treating endomorphisms on nets of von Neumann algebras in terms of the apparently simpler objects of weights on half-sided modular inclusions, we lastly give some basic results for manipulations with such weights

Wave propagation through a flexoelectric piezoelectric slab sandwiched by two piezoelectric half-spaces.

Science.gov (United States)

Jiao, Fengyu; Wei, Peijun; Li, Yueqiu

2018-01-01

Reflection and transmission of plane waves through a flexoelectric piezoelectric slab sandwiched by two piezoelectric half-spaces are studied in this paper. The secular equations in the flexoelectric piezoelectric material are first derived from the general governing equation. Different from the classical piezoelectric medium, there are five kinds of coupled elastic waves in the piezoelectric material with the microstructure effects taken into consideration. The state vectors are obtained by the summation of contributions from all possible partial waves. The state transfer equation of flexoelectric piezoelectric slab is derived from the motion equation by the reduction of order, and the transfer matrix of flexoelectric piezoelectric slab is obtained by solving the state transfer equation. By using the continuous conditions at the interface and the approach of partition matrix, we get the resultant algebraic equations in term of the transfer matrix from which the reflection and transmission coefficients can be calculated. The amplitude ratios and further the energy flux ratios of various waves are evaluated numerically. The numerical results are shown graphically and are validated by the energy conservation law. Based on these numerical results, the influences of two characteristic lengths of microstructure and the flexoelectric coefficients on the wave propagation are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

A new consistent definition of the homogenized diffusion coefficient of a lattice, limitations of the homogenization concept, and discussion of previously defined coefficients

International Nuclear Information System (INIS)

Deniz, V.C.

1980-01-01

The problem concerned with the correct definition of the homogenized diffusion coefficient of a lattice, and the concurrent problem of whether or not a homogenized diffusion equation can be formally set up, is studied by a space-energy-angle dependent treatment for a general lattice cell using an operator notation which applies to any eigen-problem. A new definition of the diffusion coefficient is given, which combines within itself the individual merits of the two definitions of Benoist. The relation between the new coefficient and the ''uncorrected'' Benoist coefficient is discussed by considering continuous-spectrum and multi-group diffusion equations. Other definitions existing in the literature are briefly discussed. It is concluded that a diffusion coefficient should represent only leakage effects. A comparison is made between the homogenization approach and the approach via eigen-coefficients, and brief indications are given of a possible scheme for the latter. (author)

Gauge freedom in perfect fluid spatially homogeneous spacetimes

International Nuclear Information System (INIS)

Jantzen, R.T.

1983-01-01

The class of reference systems compatible with the symmetry of a spatially homogeneous perfect fluid spacetime is discussed together with the associated class of symmetry adapted comoving ADM frames (or computational frames). The fluid equations of motion are related to the four functions on the space of fluid flow lines discovered by Taub and which characterize an isentropic flow. (Auth.)

The electromagnetic radiation from simple sources in the presence of a homogeneous dielectric sphere

Science.gov (United States)

Mason, V. B.

1973-01-01

In this research, the effect of a homogeneous dielectric sphere on the electromagnetic radiation from simple sources is treated as a boundary value problem, and the solution is obtained by the technique of dyadic Green's functions. Exact representations of the electric fields in the various regions due to a source located inside, outside, or on the surface of a dielectric sphere are formulated. Particular attention is given to the effect of sphere size, source location, dielectric constant, and dielectric loss on the radiation patterns and directivity of small spheres (less than 5 wavelengths in diameter) using the Huygens' source excitation. The computed results are found to closely agree with those measured for waveguide-excited plexiglas spheres. Radiation patterns for an extended Huygens' source and for curved electric dipoles located on the sphere's surface are also presented. The resonance phenomenon associated with the dielectric sphere is studied in terms of the modal representation of the radiated fields. It is found that when the sphere is excited at certain frequencies, much of the energy is radiated into the sidelobes. The addition of a moderate amount of dielectric loss, however, quickly attenuates this resonance effect. A computer program which may be used to calculate the directivity and radiation pattern of a Huygens' source located inside or on the surface of a lossy dielectric sphere is listed.

Exploration of BEOL line-space patterning options at 12 nm half-pitch and below

Science.gov (United States)

Decoster, S.; Lazzarino, F.; Petersen Barbosa Lima, L.; Li, W.; Versluijs, J.; Halder, S.; Mallik, A.; Murdoch, G.

2018-03-01

While the semiconductor industry is almost ready for high-volume manufacturing of the 7 nm technology node, research centers are defining and troubleshooting the patterning options for the 5 nm technology node (N5) and below. The target dimension for imec's N5 BEOL applications is 20-24 nm Metal Pitch (MP), which requires Self-Aligned multiple (Double/Quadruple/Octuple) Patterning approaches (SAxP) in combination with EUV or immersion lithography at 193 nm. There are numerous technical challenges to enable gratings at the hard mask level such as good uniformity across wafer, low line edge/width roughness (LER/LWR), large process window, and all of this at low cost. An even greater challenge is to transfer these gratings into the dielectric material at such critical dimensions, where increased line edge roughness, line wiggling and even pattern collapse can be expected for materials with small mechanical stability such as highly porous low-k dielectrics. In this work we first compare three different patterning options for 12 nm half-pitch gratings at the hard mask level: EUV-based SADP and 193i-based SAQP and SAOP. This comparison will be based on process window, line edge/width roughness and cost. Next, the transfer of 12 nm line/space gratings in the dielectric material is discussed and presented. The LER of the dielectric lines is investigated as a function of the dielectric material, the trench depth, and the stress in the sacrificial hard mask. Finally, we elaborate on the different options to enable scaling down from 24 nm MP to 16 nm MP, and demonstrate 8 nm line/space gratings with 193i-based SAOP.

Decoherence in quantum lossy systems: superoperator and matrix techniques

Science.gov (United States)

Yazdanpanah, Navid; Tavassoly, Mohammad Kazem; Moya-Cessa, Hector Manuel

2017-06-01

Due to the unavoidably dissipative interaction between quantum systems with their environments, the decoherence flows inevitably into the systems. Therefore, to achieve a better understanding on how decoherence affects on the damped systems, a fundamental investigation of master equation seems to be required. In this regard, finding out the missed information which has been lost due to irreversibly of the dissipative systems, is also of practical importance in quantum information science. Motivating by these facts, in this work we want to use superoperator and matrix techniques, by which we are able to illustrate two methods to obtain the explicit form of density operators corresponding to damped systems at arbitrary temperature T ≥ 0. To establish the potential abilities of the suggested methods, we apply them to deduce the density operator of some practical well-known quantum systems. Using the superoperator techniques, at first we obtain the density operator of a damped system which includes a qubit interacting with a single-mode quantized field within an optical cavity. As the second system, we study the decoherence of a quantized field within an optical damped cavity. We also use our proposed matrix method to study the decoherence of a system which includes two qubits in the interaction with each other via dipole-dipole interaction and at the same time with a quantized field in a lossy cavity. The influences of dissipation on the decoherence of dynamical properties of these systems are also numerically investigated. At last, the advantages of the proposed superoperator techniques in comparison with matrix method are explained.

SOCIAL AND ECONOMICAL DIVERSIFICATION OF THE SPACE OF THE GLIWICE CITY

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Barbara Kozielska

2005-01-01

Full Text Available City as a metaphor could be described as a living organism. It consists of many tissues with completely different functions. Cities are the sites of complex of social, cultural, politicaland economic spaces and forma. There are no cities with homogenous spatial structure. Distinct districts arise in the different parts of the city. Such process takes place in accordance with different spheres of life. Dwellings and users of the city perceive sectors indifferent ways giving them special meanings. Cities are the sites of complex global interconnections producing a multiplicity of social,cultural, political and economic spaces and forms. Over half of the world population now lives in cities and this proportion is predicted to grow significantly in coming years. We may call contemporary world as Globalopolis. The paper discusses distinct spaces and functions of different parts of the city of Gliwice. The author tries to point out multiplicity of spaces in the city. Gliwice is typical transforming city as many other in Poland during the period of economic and social transformation, which is also influented by processes of globalization. We may distinguish “good” and “bad” spaces in this transforming city.

Stresses in Coating with Gradient Interlayer caused by Contact Loading

Directory of Open Access Journals (Sweden)

Kulchytsky-Zhyhailo Roman

2014-03-01

Full Text Available The three-dimensional problem of elasticity concerning inhomogeneous half-space under normal and tangential loading applied in circular region was considered. The half-space is composed of the homogeneous body and double-layer coating which includes a homogeneous top coat and a gradient interlayer. The solution method is based on the two-dimensional integral Fourier transform. The influence of mechanical properties of coatings component and coefficient of friction on the first principal stress distribution was considered.

Lossy transmission line model of hydrofractured well dynamics

Energy Technology Data Exchange (ETDEWEB)

Patzek, T.W. [Department of Materials Science and Mineral Engineering, University of California at Berkeley, Berkeley, CA (United States); De, A. [Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

2000-01-01

The real-time detection of hydrofracture growth is crucial to the successful operation of water, CO{sub 2} or steam injection wells in low-permeability reservoirs and to the prevention of subsidence and well failure. In this paper, we describe propagation of very low frequency (1-10 to 100 Hz) Stoneley waves in a fluid-filled wellbore and their interactions with the fundamental wave mode in a vertical hydrofracture. We demonstrate that Stoneley-wave loses energy to the fracture and the energy transfer from the wellbore to the fracture opening is most efficient in soft rocks. We conclude that placing the wave source and receivers beneath the injection packer provides the most efficient means of hydrofracture monitoring. We then present the lossy transmission line model of wellbore and fracture for the detection and characterization of fracture state and volume. We show that this model captures the wellbore and fracture geometry, the physical properties of injected fluid and the wellbore-fracture system dynamics. The model is then compared with experimentally measured well responses. The simulated responses are in good agreement with published experimental data from several water injection wells with depths ranging from 1000 ft to 9000 ft. Hence, we conclude that the transmission line model of water injectors adequately captures wellbore and fracture dynamics. Using an extensive data set for the South Belridge Diatomite waterfloods, we demonstrate that even for very shallow wells the fracture size and state can be adequately recognized at wellhead. Finally, we simulate the effects of hydrofracture extension on the transient response to a pulse signal generated at wellhead. We show that hydrofracture extensions can indeed be detected by monitoring the wellhead pressure at sufficiently low frequencies.

Homogenization versus homogenization-free method to measure muscle glycogen fractions.

Science.gov (United States)

Mojibi, N; Rasouli, M

2016-12-01

The glycogen is extracted from animal tissues with or without homogenization using cold perchloric acid. Three methods were compared for determination of glycogen in rat muscle at different physiological states. Two groups of five rats were kept at rest or 45 minutes muscular activity. The glycogen fractions were extracted and measured by using three methods. The data of homogenization method shows that total glycogen decreased following 45 min physical activity and the change occurred entirely in acid soluble glycogen (ASG), while AIG did not change significantly. Similar results were obtained by using "total-glycogen-fractionation methods". The findings of "homogenization-free method" indicate that the acid insoluble fraction (AIG) was the main portion of muscle glycogen and the majority of changes occurred in AIG fraction. The results of "homogenization method" are identical with "total glycogen fractionation", but differ with "homogenization-free" protocol. The ASG fraction is the major portion of muscle glycogen and is more metabolically active form.

Optimization of Error-Bounded Lossy Compression for Hard-to-Compress HPC Data

Energy Technology Data Exchange (ETDEWEB)

Di, Sheng; Cappello, Franck

2018-01-01

Since today’s scientific applications are producing vast amounts of data, compressing them before storage/transmission is critical. Results of existing compressors show two types of HPC data sets: highly compressible and hard to compress. In this work, we carefully design and optimize the error-bounded lossy compression for hard-tocompress scientific data. We propose an optimized algorithm that can adaptively partition the HPC data into best-fit consecutive segments each having mutually close data values, such that the compression condition can be optimized. Another significant contribution is the optimization of shifting offset such that the XOR-leading-zero length between two consecutive unpredictable data points can be maximized. We finally devise an adaptive method to select the best-fit compressor at runtime for maximizing the compression factor. We evaluate our solution using 13 benchmarks based on real-world scientific problems, and we compare it with 9 other state-of-the-art compressors. Experiments show that our compressor can always guarantee the compression errors within the user-specified error bounds. Most importantly, our optimization can improve the compression factor effectively, by up to 49% for hard-tocompress data sets with similar compression/decompression time cost.

Coherent control of long-distance steady-state entanglement in lossy resonator arrays

Science.gov (United States)

Angelakis, D. G.; Dai, L.; Kwek, L. C.

2010-07-01

We show that coherent control of the steady-state long-distance entanglement between pairs of cavity-atom systems in an array of lossy and driven coupled resonators is possible. The cavities are doped with atoms and are connected through waveguides, other cavities or fibers depending on the implementation. We find that the steady-state entanglement can be coherently controlled through the tuning of the phase difference between the driving fields. It can also be surprisingly high in spite of the pumps being classical fields. For some implementations where the connecting element can be a fiber, long-distance steady-state quantum correlations can be established. Furthermore, the maximal of entanglement for any pair is achieved when their corresponding direct coupling is much smaller than their individual couplings to the third party. This effect is reminiscent of the establishment of coherence between otherwise uncoupled atomic levels using classical coherent fields. We suggest a method to measure this entanglement by analyzing the correlations of the emitted photons from the array and also analyze the above results for a range of values of the system parameters, different network geometries and possible implementation technologies.

The effects of lossy compression on diagnostically relevant seizure information in EEG signals.

Science.gov (United States)

Higgins, G; McGinley, B; Faul, S; McEvoy, R P; Glavin, M; Marnane, W P; Jones, E

2013-01-01

This paper examines the effects of compression on EEG signals, in the context of automated detection of epileptic seizures. Specifically, it examines the use of lossy compression on EEG signals in order to reduce the amount of data which has to be transmitted or stored, while having as little impact as possible on the information in the signal relevant to diagnosing epileptic seizures. Two popular compression methods, JPEG2000 and SPIHT, were used. A range of compression levels was selected for both algorithms in order to compress the signals with varying degrees of loss. This compression was applied to the database of epileptiform data provided by the University of Freiburg, Germany. The real-time EEG analysis for event detection automated seizure detection system was used in place of a trained clinician for scoring the reconstructed data. Results demonstrate that compression by a factor of up to 120:1 can be achieved, with minimal loss in seizure detection performance as measured by the area under the receiver operating characteristic curve of the seizure detection system.

Slowing Quantum Decoherence by Squeezing in Phase Space

Science.gov (United States)

Le Jeannic, H.; Cavaillès, A.; Huang, K.; Filip, R.; Laurat, J.

2018-02-01

Non-Gaussian states, and specifically the paradigmatic cat state, are well known to be very sensitive to losses. When propagating through damping channels, these states quickly lose their nonclassical features and the associated negative oscillations of their Wigner function. However, by squeezing the superposition states, the decoherence process can be qualitatively changed and substantially slowed down. Here, as a first example, we experimentally observe the reduced decoherence of squeezed optical coherent-state superpositions through a lossy channel. To quantify the robustness of states, we introduce a combination of a decaying value and a rate of decay of the Wigner function negativity. This work, which uses squeezing as an ancillary Gaussian resource, opens new possibilities to protect and manipulate quantum superpositions in phase space.

Scattering of electromagnetic waves from a half-space of randomly distributed discrete scatterers and polarized backscattering ratio law

Science.gov (United States)

Zhu, P. Y.

1991-01-01

The effective-medium approximation is applied to investigate scattering from a half-space of randomly and densely distributed discrete scatterers. Starting from vector wave equations, an approximation, called effective-medium Born approximation, a particular way, treating Green's functions, and special coordinates, of which the origin is set at the field point, are used to calculate the bistatic- and back-scatterings. An analytic solution of backscattering with closed form is obtained and it shows a depolarization effect. The theoretical results are in good agreement with the experimental measurements in the cases of snow, multi- and first-year sea-ice. The root product ratio of polarization to depolarization in backscattering is equal to 8; this result constitutes a law about polarized scattering phenomena in the nature.

Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

Directory of Open Access Journals (Sweden)

F. Saez de Adana

2009-01-01

Full Text Available This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD for the analysis of Ultra-Wideband (UWB mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

Enhancement of crystal homogeneity of protein crystals under application of an external alternating current electric field

Energy Technology Data Exchange (ETDEWEB)

Koizumi, H.; Uda, S.; Fujiwara, K.; Nozawa, J. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Tachibana, M. [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, 236-0027 (Japan); Kojima, K. [Department of Education, Yokohama Soei University, 1 Miho-tyou, Midori-ku, Yokohama, 226-0015 (Japan)

2014-10-06

X-ray diffraction rocking-curve measurements were performed on tetragonal hen egg white (HEW) lysozyme crystals grown with and without the application of an external alternating current (AC) electric field. The crystal quality was assessed by the full width at half maximum (FWHM) value for each rocking curve. For two-dimensional maps of the FWHMs measured on the 440 and the 12 12 0 reflection, the crystal homogeneity was improved under application of an external electric field at 1 MHz, compared with that without. In particular, the significant improvement of the crystal homogeneity was observed for the 12 12 0 reflection.

SU-F-I-75: Half-Value Layer Thicknesses and Homogeneity Coefficients for Fluoroscopic X-Ray Beam Spectra Incorporating Spectral Filtration

Energy Technology Data Exchange (ETDEWEB)

Wunderle, K [Cleveland Clinic Foundation, Cleveland, OH (United States); Wayne State University School of Medicine, Detroit, MI (United States); Godley, A; Shen, Z; Dong, F [Cleveland Clinic Foundation, Cleveland, OH (United States); Rakowski, J [Wayne State University School of Medicine, Detroit, MI (United States)

2016-06-15

Purpose: The purpose of this investigation is to quantify various first half-value-layers (HVLs), second HVLs and homogeneity coefficients (HCs) for a state-of-the-art fluoroscope utilizing spectral (copper) filtration. Methods: A Radcal (Monrovia, Ca) AccuPro dosimeter with a 10×6-6 calibrated ionization chamber was used to measure air kerma for radiographic x-ray exposures made on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope operated in the service mode. The ionization chamber was centered in the x-ray beam at 72 cm from the focal spot with a source-to-image-distance of 120 cm. The collimators were introduced to limit the x-ray field to approximately 5 cm × 5 cm at the ionization chamber plane. Type-1100 aluminum filters, in 0.5 mm increments, were used to determine the HVL. Two HVL calculation methods were used, log-linear interpolation and Lambert-W interpolation as described by Mathieu [Med Phys, 38(8), 4546 (2011)]. Multiple measurements were made at 60, 80, 100, 120 kVp at spectral filtration thicknesses of 0, 0.1, 0.3, 0.6 and 0.9 mm. Results: First HVL, second HVL, and HCs are presented for the fluoroscopic x-ray beam spectra indicated above, with nearly identical results from the two interpolation methods. Accuracy of the set kVp was also determined and deviated less than 2%. First HVLs for fluoroscopic x-ray beam spectra without spectral filtration determined in our study were 7%–16% greater than previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)]. However, the FDA minimum HVL requirements changed since that publication, requiring larger HVLs as of 2006. Additionally, x-ray tube and generator architecture have substantially changed over the last 15 years providing different beam spectra. Conclusion: X-ray beam quality characteristics for state-of-the-art fluoroscopes with spectral filtration have not been published. This study provides reference data which will be useful for defining beam qualities encountered on

The Radiation Problem from a Vertical Hertzian Dipole Antenna above Flat and Lossy Ground: Novel Formulation in the Spectral Domain with Closed-Form Analytical Solution in the High Frequency Regime

Directory of Open Access Journals (Sweden)

K. Ioannidi

2014-01-01

Full Text Available We consider the problem of radiation from a vertical short (Hertzian dipole above flat lossy ground, which represents the well-known “Sommerfeld radiation problem” in the literature. The problem is formulated in a novel spectral domain approach, and by inverse three-dimensional Fourier transformation the expressions for the received electric and magnetic (EM field in the physical space are derived as one-dimensional integrals over the radial component of wavevector, in cylindrical coordinates. This formulation appears to have inherent advantages over the classical formulation by Sommerfeld, performed in the spatial domain, since it avoids the use of the so-called Hertz potential and its subsequent differentiation for the calculation of the received EM field. Subsequent use of the stationary phase method in the high frequency regime yields closed-form analytical solutions for the received EM field vectors, which coincide with the corresponding reflected EM field originating from the image point. In this way, we conclude that the so-called “space wave” in the literature represents the total solution of the Sommerfeld problem in the high frequency regime, in which case the surface wave can be ignored. Finally, numerical results are presented, in comparison with corresponding numerical results based on Norton’s solution of the problem.

Indentation theory on a half-space of transversely isotropic multi-ferroic composite medium: sliding friction effect

Science.gov (United States)

Wu, F.; Wu, T.-H.; Li, X.-Y.

2018-03-01

This article aims to present a systematic indentation theory on a half-space of multi-ferroic composite medium with transverse isotropy. The effect of sliding friction between the indenter and substrate is taken into account. The cylindrical flat-ended indenter is assumed to be electrically/magnetically conducting or insulating, which leads to four sets of mixed boundary-value problems. The indentation forces in the normal and tangential directions are related to the Coulomb friction law. For each case, the integral equations governing the contact behavior are developed by means of the generalized method of potential theory, and the corresponding coupling field is obtained in terms of elementary functions. The effect of sliding on the contact behavior is investigated. Finite element method (FEM) in the context of magneto-electro-elasticity is developed to discuss the validity of the analytical solutions. The obtained analytical solutions may serve as benchmarks to various simplified analyses and numerical codes and as a guide for future experimental studies.

A Potential Method for Body and Surface Wave Propagation in Transversely Isotropic Half- and Full-Spaces

Directory of Open Access Journals (Sweden)

Mehdi Raoofian Naeeni

2016-12-01

Full Text Available The problem of propagation of plane wave including body and surface waves propagating in a transversely isotropic half-space with a depth-wise axis of material symmetry is investigated in details. Using the advantage of representation of displacement fields in terms of two complete scalar potential functions, the coupled equations of motion are uncoupled and reduced to two independent equations for potential functions. In this paper, the secular equations for determination of body and surface wave velocities are derived in terms of both elasticity coefficients and the direction of propagation. In particular, the longitudinal, transverse and Rayleigh wave velocities are determined in explicit forms. It is also shown that in transversely isotropic materials, a Rayleigh wave may propagate in different manner from that of isotropic materials. Some numerical results for synthetic transversely isotropic materials are also illustrated to show the behavior of wave motion due to anisotropic nature of the problem.

The combined effect of side-coupled gain cavity and lossy cavity on the plasmonic response of metal-dielectric-metal surface plasmon polariton waveguide

International Nuclear Information System (INIS)

Zhu, Qiong-gan; Wang, Zhi-guo; Tan, Wei

2014-01-01

The combined effect of side-coupled gain cavity and lossy cavity on the plasmonic response of metal-dielectric-metal (MDM) surface plasmon polariton (SPP) waveguide is investigated theoretically using Green's function method. Our result suggests that the gain and loss parameters influence the amplitude and phase of the fields localized in the two cavities. For the case of balanced gain and loss, the fields of the two cavities are always of equi-amplitude but out of phase. A plasmon induced transparency (PIT)-like transmission peak can be achieved by the destructive interference of two fields with anti-phase. For the case of unbalanced gain and loss, some unexpected responses of structure are generated. When the gain is more than the loss, the system response is dissipative at around the resonant frequency of the two cavities, where the sum of reflectance and transmittance becomes less than one. This is because the lossy cavity, with a stronger localized field, makes the main contribution to the system response. When the gain is less than the loss, the reverse is true. It is found that the metal loss dissipates the system energy but facilitates the gain cavity to make a dominant effect on the system response. This mechanism may have a potential application for optical amplification and for a plasmonic waveguide switch. (paper)

Method of the characteristics for calculation of VVER without homogenization

Energy Technology Data Exchange (ETDEWEB)

Suslov, I.R.; Komlev, O.G.; Novikova, N.N.; Zemskov, E.A.; Tormyshev, I.V.; Melnikov, K.G.; Sidorov, E.B. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

2005-07-01

The first stage of the development of characteristics code MCCG3D for calculation of the VVER-type reactor without homogenization is presented. The parallel version of the code for MPI was developed and tested on cluster PC with LINUX-OS. Further development of the MCCG3D code for design-level calculations with full-scale space-distributed feedbacks is discussed. For validation of the MCCG3D code we use the critical assembly VENUS-2. The geometrical models with and without homogenization have been used. With both models the MCCG3D results agree well with the experimental power distribution and with results generated by the other codes, but model without homogenization provides better results. The perturbation theory for MCCG3D code is developed and implemented in the module KEFSFGG. The calculations with KEFSFGG are in good agreement with direct calculations. (authors)

Half-maximal supersymmetry from exceptional field theory

Energy Technology Data Exchange (ETDEWEB)

Malek, Emanuel [Arnold Sommerfeld Center for Theoretical Physics, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen (Germany)

2017-10-15

We study D ≥ 4-dimensional half-maximal flux backgrounds using exceptional field theory. We define the relevant generalised structures and also find the integrability conditions which give warped half-maximal Minkowski{sub D} and AdS{sub D} vacua. We then show how to obtain consistent truncations of type II / 11-dimensional SUGRA which break half the supersymmetry. Such truncations can be defined on backgrounds admitting exceptional generalised SO(d - 1 - N) structures, where d = 11 - D, and N is the number of vector multiplets obtained in the lower-dimensional theory. Our procedure yields the most general embedding tensors satisfying the linear constraint of half-maximal gauged SUGRA. We use this to prove that all D ≥ 4 half-maximal warped AdS{sub D} and Minkowski{sub D} vacua of type II / 11-dimensional SUGRA admit a consistent truncation keeping only the gravitational supermultiplet. We also show to obtain heterotic double field theory from exceptional field theory and comment on the M-theory / heterotic duality. In five dimensions, we find a new SO(5, N) double field theory with a (6 + N)-dimensional extended space. Its section condition has one solution corresponding to 10-dimensional N = 1 supergravity and another yielding six-dimensional N = (2, 0) SUGRA. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Non-homogeneous polymer model for wave propagation and its ...

African Journals Online (AJOL)

user

density are functions of space i.e. non-homogeneous engineering material. .... The Solution of equation Eq. (9) in the form of Eq. (10) can be obtained by taking a phase ..... Viscoelastic Model Applied to a Particular Case .... p m i exp m α α σ σ σ. = −. +. −. (35). The progressive harmonic wave which starts from the end. 0 x =.

7 CFR 58.920 - Homogenization.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Homogenization. 58.920 Section 58.920 Agriculture... Procedures § 58.920 Homogenization. Where applicable concentrated products shall be homogenized for the... homogenization and the pressure at which homogenization is accomplished will be that which accomplishes the most...

Half-and-Half Palatoplasty.

Science.gov (United States)

Han, Hyun Ho; Kang, In Sook; Rhie, Jong Won

2014-08-01

A 14-month-old child was diagnosed with a Veau Class II cleft palate. Von Langenbeck palatoplasty was performed for the right palate, and V-Y pushback palatoplasty was performed for the left palate. The child did not have a special problem during the surgery, and the authors were able to elongate the cleft by 10 mm. Contrary to preoperative concerns regarding the hybrid use of palatoplasties, the uvula and midline incisions remained balanced in the middle. The authors named this combination method "half-and-half palatoplasty" and plan to conduct a long-term follow up study as a potential solution that minimizes the complications of palatoplasty.

Cosmic Ray Hit Detection with Homogenous Structures

Science.gov (United States)

Smirnov, O. M.

Cosmic ray (CR) hits can affect a significant number of pixels both on long-exposure ground-based CCD observations and on the Space Telescope frames. Thus, methods of identifying the damaged pixels are an important part of the data preprocessing for practically any application. The paper presents an implementation of a CR hit detection algorithm based on a homogenous structure (also called cellular automata ), a concept originating in artificial intelligence and dicrete mathematics. Each pixel of the image is represented by a small automaton, which interacts with its neighbors and assumes a distinct state if it ``decides'' that a CR hit is present. On test data, the algorithm has shown a high detection rate (~0.7 ) and a low false alarm rate (frame. A homogenous structure is extremely trainable, which can be very important for processing large batches of data obtained under similar conditions. Training and optimizing issues are discussed, as well as possible other applications of this concept to image processing.

Propagation of waves in micropolar generalized thermoelastic materials with two temperatures bordered with layers or half-spaces of inviscid liquid

Directory of Open Access Journals (Sweden)

Rajneesh Kumar

Full Text Available The aim of the present paper is to study the propagation of Lamb waves in micropolar generalized thermoelastic solids with two temperatures bordered with layers or half-spaces of inviscid liquid subjected to stress-free boundary conditions in the context of Green and Lindsay (G-L theory. The secular equations for governing the symmetric and skew-symmetric leaky and nonleaky Lamb wave modes of propagation are derived. The computer simulated results with respect to phase velocity, attenuation coefficient, amplitudes of dilatation, microrotation vector and heat flux in case of symmetric and skew-symmetric modes have been depicted graphically. Moreover, some particular cases of interest have also been discussed.

Principal distance constraint error diffusion algorithm for homogeneous dot distribution

Science.gov (United States)

Kang, Ki-Min; Kim, Choon-Woo

1999-12-01

The perceived quality of the halftoned image strongly depends on the spatial distribution of the binary dots. Various error diffusion algorithms have been proposed for realizing the homogeneous dot distribution in the highlight and shadow regions. However, they are computationally expensive and/or require large memory space. This paper presents a new threshold modulated error diffusion algorithm for the homogeneous dot distribution. The proposed method is applied exactly same as the Floyd-Steinberg's algorithm except the thresholding process. The threshold value is modulated based on the difference between the distance to the nearest minor pixel, `minor pixel distance', and the principal distance. To do so, calculation of the minor pixel distance is needed for every pixel. But, it is quite time consuming and requires large memory resources. In order to alleviate this problem, `the minor pixel offset array' that transforms the 2D history of minor pixels into the 1D codes is proposed. The proposed algorithm drastically reduces the computational load and memory spaces needed for calculation of the minor pixel distance.

Coprecipitation of cadmium with copper 8-hydroxyquinolate from homogeneous solution

International Nuclear Information System (INIS)

Takiyama, Kazuyoshi; Kozen, Terumi; Ueki, Yasuyo; Ishida, Hiromi

1976-01-01

The coprecipitation of copper and cadmium 8-hydroxyquinolates from homogeneous solution was conducted from the viewpoint of crystal and analytical chemistry. To the mixed solution containing copper and cadmium ions an 8-acetoxyquinoline solution was added by keeping the pH of the solution at 9 and the resulted solution was stirred at 25 0 C. The precipitate formed at each stage of the reaction was analyzed. The precipitates in an initial stage were composed of needle crystals which characterizes copper 8-hydroxyquinolate, and were associated with a slight amount of cadmium. The first half of the coprecipitation curve for the needle crystal formation resembles the logarithmic distribution curve of lambda equal to about 0.01. The precipitation of most of the copper ions was followed by the precipitation of cadmium 8-hydroxyquinolate crystal in the plate form. The needle crystals of copper 8-hydroxyquinolate started to dissolve and transformed to plate crystals. In the second half of the coprecipitation, both crystals, owing to the identical crystal structure, precipitated simultaneously and form a solid solution. When cadmium 8-hydroxyquinolate was precipitated by the PFHS method (precipitation from homogeneous solution) in the presence of the needle crystals of copper 8-hydroxyquinolate, the above mentioned phenomenon was observed. The precipitation of cadmium 8-hydroxyquinolate in the plate form is due to the seeding effect of the plate crystals of copper 8-hydroxyquinolate, which were scantily transformed from the needle crystals. The plate crystals of cadmium compound acts as a seed to transform the needle crystals of copper compound to plate crystals. (auth.)

A new consistent definition of the homogenized diffusion coefficient of a lattice, limitations of the homogenization concept, and discussion of previously defined coefficients

International Nuclear Information System (INIS)

Deniz, V.C.

1978-01-01

The problem concerned with the correct definition of the homogenized diffusion coefficient of a lattice, and the concurrent problem of whether or not a homogenized diffusion equation can be formally set up, is studied by a space-energy angle dependent treatment for a general lattice cell; using an operator notation which applies to any eigen-problem. It is shown that the diffusion coefficient should represent only leakage effects. A new definition of the diffusion coefficient is given, which combines within itself the individual merits of each of the two definitions of Benoist, and reduces to the 'uncorrected' Benoist coefficient in certain cases. The conditions under which a homogenized diffusion equation can be obtained are discussed. A compatison is made between the approach via a diffusion equation and the approach via the eigen-coefficients of Deniz. Previously defined diffusion coefficients are discussed, and it is shown that the transformed eigen-coefficients proposed by Gelbard and by Larsen are unsuitable as diffusion coefficients, and that the cell-edge normalization of the Bonalumi coefficient is not physically justifiable. (author)

Diffusive transport of radon in a homogeneous column of dry sand

NARCIS (Netherlands)

van der Spoel, W.H.; van der Graaf, E.R.; de Meijer, R.J.

To validate a model for radon transport in soil, measurements of diffusive radon transport under well-defined and controlled conditions have been made in a homogeneous column of dry sand with an air-filled volume on top. This volume simulates a crawl space. The measurements concern time-dependent

Design course in space astronomy

International Nuclear Information System (INIS)

Dean, A J; Perez-Fournon, I

2003-01-01

The aim of this course is to provide direct experience of collaboration with other European astronomy/space science students and to gain an insight into the establishment of ESA space science programmes. The first half of the course takes place in Southampton. The Southampton students work as a team to track a past ESA space science mission from initial conception through to final realization and operations. This is achieved through the study of the high quality documentation available in the form of ESA reports. Each student has well defined responsibilities within the team. The second half of the course takes place in Tenerife, at the University of La Laguna. Again the students are expected to complete a team study of a space science mission. This time, however, there are important differences: the study teams are now international, approximately half Southampton and half University of La Laguna students; and this time they are expected to design a completely new space astronomy mission with clearly specified scientific objectives and operational constraints

Tailoring properties of lossy-mode resonance optical fiber sensors with atomic layer deposition technique

Science.gov (United States)

Kosiel, Kamil; Koba, Marcin; Masiewicz, Marcin; Śmietana, Mateusz

2018-06-01

The paper shows application of atomic layer deposition (ALD) technique as a tool for tailoring sensorial properties of lossy-mode-resonance (LMR)-based optical fiber sensors. Hafnium dioxide (HfO2), zirconium dioxide (ZrO2), and tantalum oxide (TaxOy), as high-refractive-index dielectrics that are particularly convenient for LMR-sensor fabrication, were deposited by low-temperature (100 °C) ALD ensuring safe conditions for thermally vulnerable fibers. Applicability of HfO2 and ZrO2 overlays, deposited with ALD-related atomic level thickness accuracy for fabrication of LMR-sensors with controlled sensorial properties was presented. Additionally, for the first time according to our best knowledge, the double-layer overlay composed of two different materials - silicon nitride (SixNy) and TaxOy - is presented for the LMR fiber sensors. The thin films of such overlay were deposited by two different techniques - PECVD (the SixNy) and ALD (the TaxOy). Such approach ensures fast overlay fabrication and at the same time facility for resonant wavelength tuning, yielding devices with satisfactory sensorial properties.

Homogeneous SiGe crystal growth in microgravity by the travelling liquidus-zone method

International Nuclear Information System (INIS)

Kinoshita, K; Arai, Y; Inatomi, Y; Sakata, K; Takayanagi, M; Yoda, S; Miyata, H; Tanaka, R; Sone, T; Yoshikawa, J; Kihara, T; Shibayama, H; Kubota, Y; Shimaoka, T; Warashina, Y

2011-01-01

Homogeneous SiGe crystal growth experiments will be performed on board the ISS 'Kibo' using a gradient heating furnace (GHF). A new crystal growth method invented for growing homogeneous mixed crystals named 'travelling liquidus-zone (TLZ) method' is evaluated by the growth of Si 0.5 Ge 0.5 crystals in space. We have already succeeded in growing homogeneous 2mm diameter Si 0.5 Ge 0.5 crystals on the ground but large diameter homogeneous crystals are difficult to be grown due to convection in a melt. In microgravity, larger diameter crystals can be grown with suppressing convection. Radial concentration profiles as well as axial profiles in microgravity grown crystals will be measured and will be compared with our two-dimensional TLZ growth model equation and compositional variation is analyzed. Results are beneficial for growing large diameter mixed crystals by the TLZ method on the ground. Here, we report on the principle of the TLZ method for homogeneous crystal growth, results of preparatory experiments on the ground and plan for microgravity experiments.

Micro segregation and homogenization treatments of uranium-niobium alloys (U-Nb)

International Nuclear Information System (INIS)

Leal, Jose Fernando

1988-01-01

In the following sections micro segregation results in 0-3,6 wt% Nb and U-6,1 wt% Nb alloys casted in no consumable electrode arc furnace are presented. The micro segregation is studied qualitatively by optical microscopy and quantitatively by electron microprobe. The degree of homogenization has been measured after 800 and 850 deg C heat treatments in tubular resistive furnace. The microstructures after heat treatments are quantitatively analysed to check effects on the casting structures, mainly the variations in solute along the dendrite arm spacing. Some solidification phenomena are then discussed on reference to theoretical models of dendritic solidification , including microstructure and micro segregation. The experimental results are compared to theoretical on basis of initial and residual micro segregation after homogenization treatments. The times required for homogenization of the alloys are also discussed in function of the micro segregation from casting structures and the temperatures of the treatments. (author)

Impact of homogenization of pasteurized human milk on gastric digestion in the preterm infant: A randomized controlled trial.

Science.gov (United States)

de Oliveira, Samira C; Bellanger, Amandine; Ménard, Olivia; Pladys, Patrick; Le Gouar, Yann; Henry, Gwénaële; Dirson, Emelyne; Rousseau, Florence; Carrière, Frédéric; Dupont, Didier; Bourlieu, Claire; Deglaire, Amélie

2017-08-01

It has been suggested that homogenization of Holder-pasteurized human milk (PHM) could improve fat absorption and weight gain in preterm infants, but the impact on the PHM digestive kinetics has never been studied. Our objective was to determine the impact of PHM homogenization on gastric digestion in preterm infants. In a randomized controlled trial, eight hospitalized tube-fed preterm infants were their own control to compare the gastric digestion of PHM and of homogenized PHM (PHHM). PHM was obtained from donors and, for half of it, was homogenized by ultrasonication. Over a six-day sequence, gastric aspirates were collected twice a day, before and 35, 60 or 90 min after the start of PHM or PHHM ingestion. The impact of homogenization on PHM digestive kinetics and disintegration was tested using a general linear mixed model. Results were expressed as means ± SD. Homogenization leaded to a six-fold increase in the specific surface (P Homogenization increased the gastric lipolysis level (P Homogenization enhanced the proteolysis of serum albumin (P Homogenization of PHM increased the gastric lipolysis level. This could be a potential strategy to improve fat absorption, and thus growth and development in infants fed with PHM; however, its gastrointestinal tolerance needs to be investigated further. This trial was registered at clinicaltrials.gov as NCT02112331. Copyright © 2017 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

Homogenization of Mammalian Cells.

Science.gov (United States)

de Araújo, Mariana E G; Lamberti, Giorgia; Huber, Lukas A

2015-11-02

Homogenization is the name given to the methodological steps necessary for releasing organelles and other cellular constituents as a free suspension of intact individual components. Most homogenization procedures used for mammalian cells (e.g., cavitation pump and Dounce homogenizer) rely on mechanical force to break the plasma membrane and may be supplemented with osmotic or temperature alterations to facilitate membrane disruption. In this protocol, we describe a syringe-based homogenization method that does not require specialized equipment, is easy to handle, and gives reproducible results. The method may be adapted for cells that require hypotonic shock before homogenization. We routinely use it as part of our workflow to isolate endocytic organelles from mammalian cells. © 2015 Cold Spring Harbor Laboratory Press.

Functionality and homogeneity.

NARCIS (Netherlands)

2011-01-01

Functionality and homogeneity are two of the five Sustainable Safety principles. The functionality principle aims for roads to have but one exclusive function and distinguishes between traffic function (flow) and access function (residence). The homogeneity principle aims at differences in mass,

Homogenization of resonant chiral metamaterials

DEFF Research Database (Denmark)

Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten

2010-01-01

Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....

TLP bonding of dissimilar FSX-414/IN-738 system with MBF-80 interlayer: The effect of homogenizing treatment on microstructure and mechanical properties

International Nuclear Information System (INIS)

Abbasi-Khazaei, Bijan; Jahanbakhsh, Abbas; Bakhtiari, Reza

2016-01-01

In the present work, the effect of homogenizing time and temperature on the mechanical properties and microstructural evaluation of dissimilar IN-738/MBF-80/FSX-414 TLP joints was studied. The joints were made at the optimum bonding temperature of 1150 °C and homogenized at 1175, 1200 and 1225 °C for 1–6 h. Light and electron microscopes were used to investigate the microstructure. To study the hardness and alloying elements concentration profiles across the joints, the microhardness test and Wave length-Dispersive x-ray Spectroscopy (WDS) analysis were used, respectively. x-Ray Diffraction was used for identification of the phases. Shear tests were performed to measure shear strength of the joints. The results showed that, after homogenizing treatment at 1200 °C for 3 h, undesirable phases in the joint region were eliminated markedly while these phases were stable after 1 h homogenizing at the same temperature. Recrystalization at the joint region close to the FSX-414 base metal was seen at this temperature. At the same region, homogenizing treatment at 1225 °C led to intercellular carbide dissolving and recrystallization. At this temperature, grain boundaries liquation and precipitation coarsening occurred. The results of shear tests showed that, the shear strength of the joints was enhanced by about twice after homogenizing at 1200 °C in respect to the as-bonded samples. - Highlights: • Homogenizing temperature of 1175 °C was not sufficient to remove undesirable phases such as carbides and borides in DAZ of FSX-414 half. • Undesirable phases at the joints were eliminated markedly after homogenizing at 1200 °C for 3 h. • Carbide dissolving, recrystallization, partially melting and precipitation coarsening occurred in the base metal and at the joints during homogenizing at 1225 °C. • Chromium and cobalt borides of Cr_2B, CoB and Co_4B were formed in the bonding surface of the FSX-414 half during homogenizing at 1225 °C. • Maximum shear

Quasi-Stationary Temperature Field of Two-Layer Half-Space with Moving Boundary

Directory of Open Access Journals (Sweden)

P. A. Vlasov

2015-01-01

Full Text Available Due to intensive introduction of mathematical modeling methods into engineering practice, analytical methods for solving problems of heat conduction theory along with computational methods become increasingly important. Despite the well-known limitations of the analytical method applicability, this trend is caused by many reasons. In particular, solutions of the appropriate problems presented in analytically closed form can be used to test the new efficient computational algorithms, to carry out a parametric study of the temperature field of the analyzed system and to explore specific features of its formation, to formulate and solve optimization problems. In addition, these solutions allow us to explore the possibility for simplifying mathematical model with retaining its adequacy to the studied process.The main goal of the conducted research is to provide an analytically closed-form solution to the problem of finding the quasi-stationary temperature field of the system, which is simulated by isotropic half-space with isotropic coating of constant thickness. The outer boundary of this system is exposed to the Gaussian-type heat flux and uniformly moves in parallel with itself.A two-dimensional mathematical model that takes into account the axial symmetry of the studied process has been used. After the transition to a moving coordinate system rigidly associated with a moving boundary the Hankel integral transform of zero order (with respect to the radial variable and the Laplace transform (with respect to the temporal variable were used. Next, the image of the Hankel transform for the stationary temperature field of the system with respect to the moving coordinate system was found using a limit theorem of operational calculus. This allowed representing the required quasi-stationary field in the form of an improper integral of the first kind, which depends on the parameters. This result obtained can be used to conduct a parametric study and solve

Effects of two-temperature parameter and thermal nonlocal parameter on transient responses of a half-space subjected to ramp-type heating

Science.gov (United States)

Xue, Zhang-Na; Yu, Ya-Jun; Tian, Xiao-Geng

2017-07-01

Based upon the coupled thermoelasticity and Green and Lindsay theory, the new governing equations of two-temperature thermoelastic theory with thermal nonlocal parameter is formulated. To more realistically model thermal loading of a half-space surface, a linear temperature ramping function is adopted. Laplace transform techniques are used to get the general analytical solutions in Laplace domain, and the inverse Laplace transforms based on Fourier expansion techniques are numerically implemented to obtain the numerical solutions in time domain. Specific attention is paid to study the effect of thermal nonlocal parameter, ramping time, and two-temperature parameter on the distributions of temperature, displacement and stress distribution.

Finite Thin Cover on an Orthotropic Elastic Half Plane

Directory of Open Access Journals (Sweden)

Federico Oyedeji Falope

2016-01-01

Full Text Available The present work deals with the mechanical behaviour of thin films bonded to a homogeneous elastic orthotropic half plane under plain strain condition and infinitesimal strain. Both the film and semi-infinite substrate display linear elastic orthotropic behaviour. By assuming perfect adhesion between film and half plane together with membrane behaviour of the film, the compatibility condition between the coating and substrate leads to a singular integral equation with Cauchy kernel. Such an equation is straightforwardly solved by expanding the unknown interfacial stress in series of Chebyshev polynomials displaying square-root singularity at the film edges. This approach allows handling the singular behaviour of the shear stress and, in turn, reducing the problem to a linear algebraic system of infinite terms. Results are found for two loading cases, with particular reference to concentrated axial forces acting at the edges of the film. The corresponding mode II stress intensity factor has been assessed, thus providing the stress concentrations at both ends of the covering. Possible applications of the results here obtained range from MEMS, NEMS, and solar Silicon cell for energy harvesting to welded joint and building foundation.

Measurement of the topological charge and index of vortex vector optical fields with a space-variant half-wave plate.

Science.gov (United States)

Liu, Gui-Geng; Wang, Ke; Lee, Yun-Han; Wang, Dan; Li, Ping-Ping; Gou, Fangwang; Li, Yongnan; Tu, Chenghou; Wu, Shin-Tson; Wang, Hui-Tian

2018-02-15

Vortex vector optical fields (VVOFs) refer to a kind of vector optical field with an azimuth-variant polarization and a helical phase, simultaneously. Such a VVOF is defined by the topological index of the polarization singularity and the topological charge of the phase vortex. We present a simple method to measure the topological charge and index of VVOFs by using a space-variant half-wave plate (SV-HWP). The geometric phase grating of the SV-HWP diffracts a VVOF into ±1 orders with orthogonally left- and right-handed circular polarizations. By inserting a polarizer behind the SV-HWP, the two circular polarization states project into the linear polarization and then interfere with each other to form the interference pattern, which enables the direct measurement of the topological charge and index of VVOFs.

Development of the Plastic Melt Waste Compactor- Design and Fabrication of the Half-Scale Prototype

Science.gov (United States)

Pace, Gregory S.; Fisher, John

2005-01-01

A half scale version of a device called the Plastic Melt Waste Compactor prototype has been developed at NASA Ames Research Center to deal with plastic based wastes that are expected to be encountered in future human space exploration scenarios such as Lunar or Martian Missions. The Plastic Melt Waste Compactor design was based on the types of wastes produced on the International Space Station, Space Shuttle, MIR and Skylab missions. The half scale prototype unit will lead to the development of a full scale Plastic Melt Waste Compactor prototype that is representative of flight hardware that would be used on near and far term space missions. This report details the progress of the Plastic Melt Waste Compactor Development effort by the Solid Waste Management group at NASA Ames Research Center.

Improved magnetic-field homogeneity of NMR HTS bulk magnet using a new stacking structure and insertion of an HTS film cylinder into a bulk bore

International Nuclear Information System (INIS)

Itoh, Yoshitaka; Yanagi, Yousuke; Nakamura, Takashi

2017-01-01

A new type of superconducting bulk magnet for compact nuclear magnetic resonance (NMR) devices with high magnetic-field homogeneity has been developed by inserting an HTS film cylinder into a bulk superconductor bore. Annular 60 mmϕ Eu-Ba-Cu-O bulk superconductors with a larger inner diameter (ID) of 36 mm were sandwiched between bulk superconductors with a smaller ID of 28 mm, and the total height of the bulk superconductor set was made to be 120 mm. The inner height of central wide bore space was optimized by magnetic-field simulation so that the influence of the bulk superconductor's paramagnetic moment on applied field homogeneity was minimized during the magnetization process. An HTS film cylinder, in which Gd-Ba-Cu-O tapes were wound helically in three layers around a copper cylinder, was inserted into the bulk bore in order to compensate for the inhomogeneous field trapped by the bulk superconductor. The superconducting bulk magnet composed of the above bulk superconductor set and the film cylinder were cooled by a GM pulse tube refrigerator and magnetized at 4.747 T using the field cooling (FC) method and a conventional superconducting coil magnet adjusted to below 0.5 ppm in magnetic-field homogeneity. The NMR measurement was conducted for an H_2O sample with a diameter of 6.9 mm and a length of 10 mm by setting the sample in the center of the 20 mm ID room-temperature bore of the bulk magnet. The magnetic-field homogeneity derived from the full width at half maximum (FWHM) of the "1H spectrum of H_2O was 0.45 ppm. We confirmed that the HTS film inner cylinder was effective in maintaining the homogeneity of the magnetic field applied in the magnetization process, and as a result, a magnetic field with a homogeneity of less than 1 ppm can be generated in the bore of the bulk magnet without using shim coils. (author)

H-Metric: Characterizing Image Datasets via Homogenization Based on KNN-Queries

Directory of Open Access Journals (Sweden)

Welington M da Silva

2012-01-01

Full Text Available Precision-Recall is one of the main metrics for evaluating content-based image retrieval techniques. However, it does not provide an ample perception of the properties of an image dataset immersed in a metric space. In this work, we describe an alternative metric named H-Metric, which is determined along a sequence of controlled modifications in the image dataset. The process is named homogenization and works by altering the homogeneity characteristics of the classes of the images. The result is a process that measures how hard it is to deal with a set of images in respect to content-based retrieval, offering support in the task of analyzing configurations of distance functions and of features extractors.

Project Half Double

DEFF Research Database (Denmark)

Svejvig, Per; Gerstrøm, Anna; Frederiksen, Signe Hedeboe

The Half Double mission: Project Half Double has a clear mission. We want to succeed in finding a project methodology that can increase the success rate of our projects while increasing the development speed of new products and services. We are convinced that by doing so we can strengthen...... the competitiveness of Denmark and play an important role in the battle for jobs and future welfare. The overall goal is to deliver “Projects in half the time with double the impact” where projects in half the time should be understood as half the time to impact (benefit realization, effect is achieved......) and not as half the time for project execution. The Half Double project journey: It all began in May 2013 when we asked ourselves: How do we create a new and radical project paradigm that can create successful projects? Today we are a movement of hundreds of passionate project people, and it grows larger...

Microsegregation of heat and homogenization treatments in uranium-niobium alloys (U-Nb)

International Nuclear Information System (INIS)

Leal, J.F.

1988-01-01

In the following sections microsegration results in U-3,6 Wt% Nb and U-6,1 Wt% Nb alloys casted in noconsumable electrode arc furnace are presented. The microsegration is studied qualitatively by optical microscopy and quantitatively by electron microprobe. The degree of homogenization has been measured after 800 and 850 0 C heat treatments in tubular resistive furnace. The microstructures after heat treatments are quantitatively analysed to check effects on the casting structures, mainly the variations in solute along the dendrite arm spacing. Some solidification phenomena are then discussed on reference to theorical models of dendritic solidification, including microstructure and microsegregation. The experimental results are compared to theoretical on basis of initial and residual microsegregation after homogenization treatments. The times required for homogenization of the alloys are also discussed in function of the microsegregation from casting structures and the temperatures of the treatments. (author) [pt

Genetic optimization of magneto-optic Kerr effect in lossy cavity-type magnetophotonic crystals

Energy Technology Data Exchange (ETDEWEB)

Ghanaatshoar, M., E-mail: m-ghanaat@cc.sbu.ac.i [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin 1983963113, Tehran (Iran, Islamic Republic of); Alisafaee, H. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin 1983963113, Tehran (Iran, Islamic Republic of)

2011-07-15

We have demonstrated an optimization approach in order to obtain desired magnetophotonic crystals (MPCs) composed of a lossy magnetic layer (TbFeCo) placed within a multilayer structure. The approach is an amalgamation between a 4x4 transfer matrix method and a genetic algorithm. Our objective is to enhance the magneto-optic Kerr effect of TbFeCo at short visible wavelength of 405 nm. Through the optimization approach, MPC structures are found meeting definite criteria on the amount of reflectivity and Kerr rotation. The resulting structures are fitted more than 99.9% to optimization criteria. Computation of the internal electric field distribution shows energy localization in the vicinity of the magnetic layer, which is responsible for increased light-matter interaction and consequent enhanced magneto-optic Kerr effect. Versatility of our approach is also exhibited by examining and optimizing several MPC structures. - Research highlights: Structures comprising a highly absorptive TbFeCo layer are designed to work for data storage applications at 405 nm. Optimization algorithm resulted in structures fitted 99.9% to design criteria. More than 10 structures are found exhibiting magneto-optical response of about 1{sup o} rotation and 20% reflection. The ratio of the Kerr rotation to the Kerr ellipticity is enhanced by a factor of 30.

Homogeneous crystal nucleation in polymers.

Science.gov (United States)

Schick, C; Androsch, R; Schmelzer, J W P

2017-11-15

The pathway of crystal nucleation significantly influences the structure and properties of semi-crystalline polymers. Crystal nucleation is normally heterogeneous at low supercooling, and homogeneous at high supercooling, of the polymer melt. Homogeneous nucleation in bulk polymers has been, so far, hardly accessible experimentally, and was even doubted to occur at all. This topical review summarizes experimental findings on homogeneous crystal nucleation in polymers. Recently developed fast scanning calorimetry, with cooling and heating rates up to 10 6 K s -1 , allows for detailed investigations of nucleation near and even below the glass transition temperature, including analysis of nuclei stability. As for other materials, the maximum homogeneous nucleation rate for polymers is located close to the glass transition temperature. In the experiments discussed here, it is shown that polymer nucleation is homogeneous at such temperatures. Homogeneous nucleation in polymers is discussed in the framework of the classical nucleation theory. The majority of our observations are consistent with the theory. The discrepancies may guide further research, particularly experiments to progress theoretical development. Progress in the understanding of homogeneous nucleation is much needed, since most of the modelling approaches dealing with polymer crystallization exclusively consider homogeneous nucleation. This is also the basis for advancing theoretical approaches to the much more complex phenomena governing heterogeneous nucleation.

Controllable synthesis of nickel bicarbonate nanocrystals with high homogeneity for a high-performance supercapacitor

Science.gov (United States)

Gu, Jianmin; Liu, Xin; Wang, Zhuang; Bian, Zhenpan; Jin, Cuihong; Sun, Xiao; Yin, Baipeng; Wu, Tianhui; Wang, Lin; Tang, Shoufeng; Wang, Hongchao; Gao, Faming

2017-08-01

The electrochemical performance of supercapacitors might be associated with the homogeneous structure of the electrode materials. However, the relationship between the degree of uniformity for the electrode materials and the electrochemical performance of the supercapacitor is not clear. Herein, we synthesize two types of nickel bicarbonate nanocrystals with different degrees of uniformity to investigate this relationship. As the electroactive material, the nickel bicarbonate nanocrystals with a homogeneous structure could provide a larger space and offer more exposed atoms for the electrochemical reaction than the nanocrystals with a heterogeneous structure. The homogeneous nickel bicarbonate nanocrystals exhibit better electrochemical performance and show excellent specific capacitance (1596 F g-1 at 2 A g-1 and 1260 F g-1 at 30 A g-1), which is approximately twice that of the heterogeneous nickel bicarbonate nanocrystals. The cycling stability for the homogeneity (˜80%) is higher than the inhomogeneity (˜61%) at a high current density of 5 A g-1.

Feasibility Study of Aseptic Homogenization: Affecting Homogenization Steps on Quality of Sterilized Coconut Milk

Directory of Open Access Journals (Sweden)

Phungamngoen Chanthima

2016-01-01

Full Text Available Coconut milk is one of the most important protein-rich food sources available today. Separation of an emulsion into an aqueous phase and cream phase is commonly occurred and this leads an unacceptably physical defect of either fresh or processed coconut milk. Since homogenization steps are known to affect the stability of coconut milk. This work was aimed to study the effect of homogenization steps on quality of coconut milk. The samples were subject to high speed homogenization in the range of 5000-15000 rpm under sterilize temperatures at 120-140 °C for 15 min. The result showed that emulsion stability increase with increasing speed of homogenization. The lower fat particles were generated and easy to disperse in continuous phase lead to high stability. On the other hand, the stability of coconut milk decreased, fat globule increased, L value decreased and b value increased when the high sterilization temperature was applied. Homogenization after heating led to higher stability than homogenization before heating due to the reduced particle size of coconut milk after aggregation during sterilization process. The results implied that homogenization after sterilization process might play an important role on the quality of the sterilized coconut milk.

Spinorial characterizations of surfaces into three-dimensional homogeneous manifolds

Science.gov (United States)

Roth, Julien

2010-06-01

We give spinorial characterizations of isometrically immersed surfaces into three-dimensional homogeneous manifolds with four-dimensional isometry group in terms of the existence of a particular spinor field. This generalizes works by Friedrich for R3 and Morel for S3 and H3. The main argument is the interpretation of the energy-momentum tensor of such a spinor field as the second fundamental form up to a tensor depending on the structure of the ambient space.

Efficacy of Ultrasonic Homogenization in the Separation of Benzene-n-Heptane Mixture by Liquid Membrane

Energy Technology Data Exchange (ETDEWEB)

Kim, B.S.; Chung, T.S. [Department of Chemical Engineering, Sung Kyun Kwan University, Seoul (Korea)

1999-04-01

In the separation of benzene-n-heptane mixture by liquid membrane, the efficacy of ultrasonic homogenization in emulsification was studied with two anionic surfactants. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether sulfate. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether stifle. The highest value of the separation factor obtained by ultrasonic homogenization was approximately three times as large as that for triethanolamine lauryl sulfate and one and a half times as large as that for sodium polyoxyethylene(2) lauryl sulfate when the mechanical stirring was used on the same operational conditions. The lowest membrane breakup was observed when the highest value of the separation factor was achieved with sodium polyoxyethylene(2) lauryl sulfate. 14 refs., 7 figs., 1 tab.

7 CFR 58.636 - Homogenization.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Homogenization. 58.636 Section 58.636 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.636 Homogenization. Homogenization of the pasteurized mix shall be accomplished to...

Benchmarking monthly homogenization algorithms

Science.gov (United States)

Venema, V. K. C.; Mestre, O.; Aguilar, E.; Auer, I.; Guijarro, J. A.; Domonkos, P.; Vertacnik, G.; Szentimrey, T.; Stepanek, P.; Zahradnicek, P.; Viarre, J.; Müller-Westermeier, G.; Lakatos, M.; Williams, C. N.; Menne, M.; Lindau, R.; Rasol, D.; Rustemeier, E.; Kolokythas, K.; Marinova, T.; Andresen, L.; Acquaotta, F.; Fratianni, S.; Cheval, S.; Klancar, M.; Brunetti, M.; Gruber, C.; Prohom Duran, M.; Likso, T.; Esteban, P.; Brandsma, T.

2011-08-01

The COST (European Cooperation in Science and Technology) Action ES0601: Advances in homogenization methods of climate series: an integrated approach (HOME) has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative). The algorithms were validated against a realistic benchmark dataset. The benchmark contains real inhomogeneous data as well as simulated data with inserted inhomogeneities. Random break-type inhomogeneities were added to the simulated datasets modeled as a Poisson process with normally distributed breakpoint sizes. To approximate real world conditions, breaks were introduced that occur simultaneously in multiple station series within a simulated network of station data. The simulated time series also contained outliers, missing data periods and local station trends. Further, a stochastic nonlinear global (network-wide) trend was added. Participants provided 25 separate homogenized contributions as part of the blind study as well as 22 additional solutions submitted after the details of the imposed inhomogeneities were revealed. These homogenized datasets were assessed by a number of performance metrics including (i) the centered root mean square error relative to the true homogeneous value at various averaging scales, (ii) the error in linear trend estimates and (iii) traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Contingency scores by themselves are not very informative. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve precipitation data

Value distribution of meromorphic solutions of homogeneous and non-homogeneous complex linear differential-difference equations

Directory of Open Access Journals (Sweden)

Luo Li-Qin

2016-01-01

Full Text Available In this paper, we investigate the value distribution of meromorphic solutions of homogeneous and non-homogeneous complex linear differential-difference equations, and obtain the results on the relations between the order of the solutions and the convergence exponents of the zeros, poles, a-points and small function value points of the solutions, which show the relations in the case of non-homogeneous equations are sharper than the ones in the case of homogeneous equations.

Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

Energy Technology Data Exchange (ETDEWEB)

Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: heinrich.lang@chemie.tu-chemnitz.de [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)

2015-03-02

A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

The Dual Half-Arc data structure: towards the universal B-rep data structure

DEFF Research Database (Denmark)

Anton, François; Bugoslawski, P.; Mioc, Darka

2014-01-01

, or more generally, the topology of any topological space. For this purpose, we generalize an existing data structure from 2D to 3D and design a new 3D data structure that realizes the synthesis between an existing 3D data structure (the Dual Half-Edge (See Footonote 1) data structure) and the generalized...... 3D Quad-Arc data structure, (See Footonote 2) and at the same time, improves the Dual Half-Edge towards a simpler and more effective representation of cell complexes through B-rep structures. We generalize the idea of the Quad-Arc data structure from 2D to 3D, but instead of transforming a simple...... edge of the Quad-Edge data structure to an arc with multiple points along it, we group together primal edges of the Dual Half-Edge that have the same dual Half-Edge vertex tags (volume tags) into one Dual Half-Arc whose dual is the common Dual Half-Edge and primal faces corresponding to dual...

Theoretical Analysis of Moving Reference Planes Associated with Unit Cells of Nonreciprocal Lossy Periodic Transmission-Line Structures

Directory of Open Access Journals (Sweden)

S. Lamultree

2017-04-01

Full Text Available This paper presents a theoretical analysis of moving reference planes associated with unit cells of nonreciprocal lossy periodic transmission-line structures (NRLSPTLSs by the equivalent bi-characteristic-impedance transmission line (BCITL model. Applying the BCITL theory, only the equivalent BCITL parameters (characteristic impedances for waves propagating in forward and reverse directions and associated complex propagation constants are of interest. An infinite NRLSPTLS is considered first by shifting a reference position of unit cells along TLs of interest. Then, a semi-infinite terminated NRLSPTLS is investigated in terms of associated load reflection coefficients. It is found that the equivalent BCITL characteristic impedances of the original and shifted unit cells are mathematically related by the bilinear transformation. In addition, the associated load reflection coefficients of both unit cells are mathematically related by the bilinear transformation. However, the equivalent BCITL complex propagation constants remain unchanged. Numerical results are provided to show the validity of the proposed theoretical analysis.

Putin's and Russian-led Eurasian Economic Union: A hybrid half-economics and half-political “Janus Bifrons”

Directory of Open Access Journals (Sweden)

Bruno S. Sergi

2018-01-01

Full Text Available The Eurasian Economic Union is an institution formalized in January 2015 for the purpose of regional economic integration; it includes five countries: Russia, Kazakhstan, Belarus, Armenia, and Kyrgyzstan, and may include Mongolia and Tajikistan in the future. With a GDP of $1.59 trillion in 2015, an industrial production of $1.3 trillion in 2014, and population of almost 200 million as of 2016, the EEAU could represent a geopolitical success that supports both Putin's ambitious political agenda and the Union's economic prospects. Although the efforts of this Union are ongoing and long-term success is not certain, the Russia-led Eurasian Economic Union can be considered a hybrid half-economics and half-political “Janus Bifrons” that serves as a powerful illustration of what Putin envisions for the post-Soviet space. Despite promising steps so far, more should be done toward the achievement of economic development and balanced opportunity for all Eurasian countries. Russia's longstanding role within the Union, as well as its power and political motivations, are all considerations that must be accounted for.

Neutron transport equation - indications on homogenization and neutron diffusion

International Nuclear Information System (INIS)

Argaud, J.P.

1992-06-01

In PWR nuclear reactor, the practical study of the neutrons in the core uses diffusion equation to describe the problem. On the other hand, the most correct method to describe these neutrons is to use the Boltzmann equation, or neutron transport equation. In this paper, we give some theoretical indications to obtain a diffusion equation from the general transport equation, with some simplifying hypothesis. The work is organised as follows: (a) the most general formulations of the transport equation are presented: integro-differential equation and integral equation; (b) the theoretical approximation of this Boltzmann equation by a diffusion equation is introduced, by the way of asymptotic developments; (c) practical homogenization methods of transport equation is then presented. In particular, the relationships with some general and useful methods in neutronic are shown, and some homogenization methods in energy and space are indicated. A lot of other points of view or complements are detailed in the text or the remarks

The SPH homogeneization method

International Nuclear Information System (INIS)

Kavenoky, Alain

1978-01-01

The homogeneization of a uniform lattice is a rather well understood topic while difficult problems arise if the lattice becomes irregular. The SPH homogeneization method is an attempt to generate homogeneized cross sections for an irregular lattice. Section 1 summarizes the treatment of an isolated cylindrical cell with an entering surface current (in one velocity theory); Section 2 is devoted to the extension of the SPH method to assembly problems. Finally Section 3 presents the generalisation to general multigroup problems. Numerical results are obtained for a PXR rod bundle assembly in Section 4

Homogeneity of Inorganic Glasses

DEFF Research Database (Denmark)

Jensen, Martin; Zhang, L.; Keding, Ralf

2011-01-01

Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...

Reflector homogenization

Energy Technology Data Exchange (ETDEWEB)

Sanchez, R.; Ragusa, J.; Santandrea, S. [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, Service d' Etudes de Reacteurs et de Modelisation Avancee, CEA de Saclay, DM2S/SERMA 91 191 Gif-sur-Yvette cedex (France)]. e-mail: richard.sanchez@cea.fr

2004-07-01

The problem of the determination of a homogeneous reflector that preserves a set of prescribed albedo is considered. Duality is used for a direct estimation of the derivatives needed in the iterative calculation of the optimal homogeneous cross sections. The calculation is based on the preservation of collapsed multigroup albedo obtained from detailed reference calculations and depends on the low-order operator used for core calculations. In this work we analyze diffusion and transport as low-order operators and argue that the P{sub 0} transfers are the best choice for the unknown cross sections to be adjusted. Numerical results illustrate the new approach for SP{sub N} core calculations. (Author)

Reflector homogenization

International Nuclear Information System (INIS)

Sanchez, R.; Ragusa, J.; Santandrea, S.

2004-01-01

The problem of the determination of a homogeneous reflector that preserves a set of prescribed albedo is considered. Duality is used for a direct estimation of the derivatives needed in the iterative calculation of the optimal homogeneous cross sections. The calculation is based on the preservation of collapsed multigroup albedo obtained from detailed reference calculations and depends on the low-order operator used for core calculations. In this work we analyze diffusion and transport as low-order operators and argue that the P 0 transfers are the best choice for the unknown cross sections to be adjusted. Numerical results illustrate the new approach for SP N core calculations. (Author)

Hybrid diffusion–transport spatial homogenization method

International Nuclear Information System (INIS)

Kooreman, Gabriel; Rahnema, Farzad

2014-01-01

Highlights: • A new hybrid diffusion–transport homogenization method. • An extension of the consistent spatial homogenization (CSH) transport method. • Auxiliary cross section makes homogenized diffusion consistent with heterogeneous diffusion. • An on-the-fly re-homogenization in transport. • The method is faster than fine-mesh transport by 6–8 times. - Abstract: A new hybrid diffusion–transport homogenization method has been developed by extending the consistent spatial homogenization (CSH) transport method to include diffusion theory. As in the CSH method, an “auxiliary cross section” term is introduced into the source term, making the resulting homogenized diffusion equation consistent with its heterogeneous counterpart. The method then utilizes an on-the-fly re-homogenization in transport theory at the assembly level in order to correct for core environment effects on the homogenized cross sections and the auxiliary cross section. The method has been derived in general geometry and tested in a 1-D boiling water reactor (BWR) core benchmark problem for both controlled and uncontrolled configurations. The method has been shown to converge to the reference solution with less than 1.7% average flux error in less than one third the computational time as the CSH method – 6 to 8 times faster than fine-mesh transport

Solidification Segregation and Homogenization Behavior of 1Cr-1.25Mo-0.25V Steel Ingot

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong-Bae [Dae-gu Mechatronics and Materials Institute, Daegu (Korea, Republic of); Na, Young-Sang; Seo, Seong-Moon [Korea Institute of Materials Science, Changwon (Korea, Republic of); Lee, Je-Hyun [Changwon National University, Changwon (Korea, Republic of)

2016-09-15

As a first step to optimizing the homogenization heat treatment following high temperature upset forging, the solidification segregation and the homogenization behaviors of solute elements were quantitatively analyzed for 1Cr-1.25Mo-0.25V steel ingot by electron probe micro-analysis (EPMA). The random sampling approach, which was designed to generate continuous compositional profiles of each solute element, was employed to clarify the segregation and homogenization behaviors. In addition, ingot castings of lab-scale and a 16-ton-sized 1Cr-1.25Mo-0.25V steel were simulated using the finite element method in three dimensions to understand the size effect of the ingot on the microsegregation and its reduction during the homogenization heat treatment. It was found that the microsegregation in a large-sized ingot was significantly reduced by the promotion of solid state diffusion due to the extremely low cooling rate. On the other hand, from the homogenization point of view, increasing the ingot size causes a dramatic increase in the dendrite arm spacing, and hence the homogenization of microsegregation in a large-sized ingot appears to be practically difficult.

Color image lossy compression based on blind evaluation and prediction of noise characteristics

Science.gov (United States)

Ponomarenko, Nikolay N.; Lukin, Vladimir V.; Egiazarian, Karen O.; Lepisto, Leena

2011-03-01

The paper deals with JPEG adaptive lossy compression of color images formed by digital cameras. Adaptation to noise characteristics and blur estimated for each given image is carried out. The dominant factor degrading image quality is determined in a blind manner. Characteristics of this dominant factor are then estimated. Finally, a scaling factor that determines quantization steps for default JPEG table is adaptively set (selected). Within this general framework, two possible strategies are considered. A first one presumes blind estimation for an image after all operations in digital image processing chain just before compressing a given raster image. A second strategy is based on prediction of noise and blur parameters from analysis of RAW image under quite general assumptions concerning characteristics parameters of transformations an image will be subject to at further processing stages. The advantages of both strategies are discussed. The first strategy provides more accurate estimation and larger benefit in image compression ratio (CR) compared to super-high quality (SHQ) mode. However, it is more complicated and requires more resources. The second strategy is simpler but less beneficial. The proposed approaches are tested for quite many real life color images acquired by digital cameras and shown to provide more than two time increase of average CR compared to SHQ mode without introducing visible distortions with respect to SHQ compressed images.

Cho decomposition of electrically charged one-half monopole

Energy Technology Data Exchange (ETDEWEB)

Ng, Ban-Loong; Teh, Rosy; Wong, Khai-Ming [School of Physics, Universiti Sains Malaysia, 11800 USM Penang (Malaysia)

2014-03-05

Recently we have carried out some work on the Cho decomposition of the electrically neutral, finite energy one-half monopole solution of the SU(2) Yang-Mills-Higgs field theory. In this paper, we performed the decomposition of the electrically charged solution using the same numerical procedure. The gauge potential of the one-half dyon solution is decomposed into Abelian and non-Abelian components. The semi-infinite string singularity in the gauge potential is a contribution of the Higgs field and hence topological in nature. The string singularity cannot be cancelled by the non-Abelian components of the gauge potential. However, the string singularity is integrable and the energy of the solution is finite. By decomposing the magnetic fields and covariant derivatives of the Higgs field into three isospin space directions, we are able to provide conclusive evidence that the constructed one-half dyon is certainly a non-BPS solution even in the limit of vanishing Higgs self-coupling constant and electric charge. Furthermore, we found that the time component of gauge function is parallel to the Higgs field in isospace only at large distances, elsewhere they are non-parallel.

Electro-magnetostatic homogenization of bianisotropic metamaterials

OpenAIRE

Fietz, Chris

2012-01-01

We apply the method of asymptotic homogenization to metamaterials with microscopically bianisotropic inclusions to calculate a full set of constitutive parameters in the long wavelength limit. Two different implementations of electromagnetic asymptotic homogenization are presented. We test the homogenization procedure on two different metamaterial examples. Finally, the analytical solution for long wavelength homogenization of a one dimensional metamaterial with microscopically bi-isotropic i...

A discrete-space urban model with environmental amenities

Science.gov (United States)

Liaila Tajibaeva; Robert G. Haight; Stephen Polasky

2008-01-01

This paper analyzes the effects of providing environmental amenities associated with open space in a discrete-space urban model and characterizes optimal provision of open space across a metropolitan area. The discrete-space model assumes distinct neighborhoods in which developable land is homogeneous within a neighborhood but heterogeneous across neighborhoods. Open...

Plane-wave spectrum approach for the calculation of electromagnetic absorption under near-field exposure conditions

International Nuclear Information System (INIS)

Chatterjee, I.; Gandhi, O.P.; Hagmann, M.J.; Riazi, A.

1980-01-01

The exposure of humans to electromagnetic near fields has not been sufficiently emphasized by researcher. We have used the plane-wave-spectrum approach to evaluate the electromagnetic field and determine the energy deposited in a lossy, homogeneous, semi-infinite slab placed in the near field of a source leaking radiation. Values of the fields and absorbed energy in the target are obtained by vector summation of the contributions of all the plane waves into which the prescribed field is decomposed. Use of a fast Fourier transform algorithm contributes to the high efficiency of the computations. The numerical results show that, for field distributions that are nearly constant over a physical extent of at least a free-space wavelength, the energy coupled into the target is approximately equal to the resulting from plane-wave exposed

Electromagnetic diffraction by an impedance cylinder buried halfway between two half-spaces

KAUST Repository

Salem, Mohamed; Kamel, Aladin Hassan

2011-01-01

We consider the problem of electromagnetic diffraction from a cylinder with impedance surface and half-buried between two dielectric media. An arbitrary located electric dipole provides the excitation. The harmonic solution is presented as a series sum over a spectrum of a discrete-index Hankel transform, and the spectral amplitudes are determined by solving an infinite linear system of equations, which is constructed by applying the orthogonality relation of the 1D Green's function. © 2011 IEEE.

Electromagnetic diffraction by an impedance cylinder buried halfway between two half-spaces

KAUST Repository

Salem, Mohamed

2011-08-01

We consider the problem of electromagnetic diffraction from a cylinder with impedance surface and half-buried between two dielectric media. An arbitrary located electric dipole provides the excitation. The harmonic solution is presented as a series sum over a spectrum of a discrete-index Hankel transform, and the spectral amplitudes are determined by solving an infinite linear system of equations, which is constructed by applying the orthogonality relation of the 1D Green\\'s function. © 2011 IEEE.

There is no non-zero stable fixed point for dense networks in the homogeneous Kuramoto model

International Nuclear Information System (INIS)

Taylor, Richard

2012-01-01

This paper is concerned with the existence of multiple stable fixed point solutions of the homogeneous Kuramoto model. We develop a necessary condition for the existence of stable fixed points for the general network Kuramoto model. This condition is applied to show that for sufficiently dense n-node networks, with node degrees at least 0.9395(n−1), the homogeneous (equal frequencies) model has only one stable fixed point solution over the full space of phase angles in the range −π to π. This is the zero fixed point solution defined by all phase angle differences being zero. This result, together with existing research, proves a conjecture of Verwoerd and Mason (2007 Proc. of the American Control Conf. pp 4613–8) that for the complete network and the homogeneous model, the zero fixed point has a basin of attraction consisting of the entire space minus a set of measure zero. The necessary conditions are also tested to see how close to sufficiency they might be by applying them to a class of regular degree networks studied by Wiley et al (2006 Chaos 16 015103). (paper)

A quantitative assessment of the scale separation limits of classical and higher-order asymptotic homogenization

NARCIS (Netherlands)

Mohammed Ameen, M.; Peerlings, R.H.J.; Geers, M.G.D.

2018-01-01

Classical homogenization techniques are known to be effective for materials with large scale separation between the size and spacing of their underlying heterogeneities on the one hand and the structural problem dimensions on the other. For low scale separation, however, they generally become

Project Half Double

DEFF Research Database (Denmark)

Svejvig, Per; Ehlers, Michael; Adland, Karoline Thorp

activities carried out within the framework of the projects. The formal part of Project Half Double was initiated in June 2015. We started out by developing, refining and testing the Half Double methodology on seven pilot projects in the first phase of the project, which will end June 2016. The current......Project Half Double has a clear mission to succeed in finding a project methodology that can increase the success rate of our projects while increasing the speed at which we generate new ideas and develop new products and services. Chaos and complexity should be seen as a basic condition...... and as an opportunity rather than a threat and a risk. We are convinced that by doing so, we can strengthen Denmark’s competitiveness and play an important role in the battle for jobs and future welfare. The overall goal is to deliver “projects in half the time with double the impact”, where projects in half the time...

Bilipschitz embedding of homogeneous fractals

OpenAIRE

Lü, Fan; Lou, Man-Li; Wen, Zhi-Ying; Xi, Li-Feng

2014-01-01

In this paper, we introduce a class of fractals named homogeneous sets based on some measure versions of homogeneity, uniform perfectness and doubling. This fractal class includes all Ahlfors-David regular sets, but most of them are irregular in the sense that they may have different Hausdorff dimensions and packing dimensions. Using Moran sets as main tool, we study the dimensions, bilipschitz embedding and quasi-Lipschitz equivalence of homogeneous fractals.

Benchmarking homogenization algorithms for monthly data

Science.gov (United States)

Venema, V. K. C.; Mestre, O.; Aguilar, E.; Auer, I.; Guijarro, J. A.; Domonkos, P.; Vertacnik, G.; Szentimrey, T.; Stepanek, P.; Zahradnicek, P.; Viarre, J.; Müller-Westermeier, G.; Lakatos, M.; Williams, C. N.; Menne, M. J.; Lindau, R.; Rasol, D.; Rustemeier, E.; Kolokythas, K.; Marinova, T.; Andresen, L.; Acquaotta, F.; Fratiannil, S.; Cheval, S.; Klancar, M.; Brunetti, M.; Gruber, C.; Prohom Duran, M.; Likso, T.; Esteban, P.; Brandsma, T.; Willett, K.

2013-09-01

The COST (European Cooperation in Science and Technology) Action ES0601: Advances in homogenization methods of climate series: an integrated approach (HOME) has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies. The algorithms were validated against a realistic benchmark dataset. Participants provided 25 separate homogenized contributions as part of the blind study as well as 22 additional solutions submitted after the details of the imposed inhomogeneities were revealed. These homogenized datasets were assessed by a number of performance metrics including i) the centered root mean square error relative to the true homogeneous values at various averaging scales, ii) the error in linear trend estimates and iii) traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve precipitation data. Moreover, state-of-the-art relative homogenization algorithms developed to work with an inhomogeneous reference are shown to perform best. The study showed that currently automatic algorithms can perform as well as manual ones.

Magnetic Half-Monopole Solutions

International Nuclear Information System (INIS)

Teh, Rosy; Lim, Kok-Geng; Koh, Pin-Wai

2009-01-01

We present exact SU(2) Yang-Mills-Higgs monopole solutions of one half topological charge. These non-Abelian solutions possess gauge potentials which are singular along either the positive or the negative z-axis and common magnetic fields that are singular only at the origin where the half-monopole is located. These half-monopoles are actually a half Wu-Yang monopole and they can possess a finite point electric charge and become half-dyons. They do not necessarily satisfy the first order Bogomol'nyi equations and they possess infinite energy density at r = 0.

Directed Thermal Diffusions through Metamaterial Source Illusion with Homogeneous Natural Media

Directory of Open Access Journals (Sweden)

Guoqiang Xu

2018-04-01

Full Text Available Owing to the utilization of transformation optics, many significant research and development achievements have expanded the applications of illusion devices into thermal fields. However, most of the current studies on relevant thermal illusions used to reshape the thermal fields are dependent of certain pre-designed geometric profiles with complicated conductivity configurations. In this paper, we propose a methodology for designing a new class of thermal source illusion devices for achieving directed thermal diffusions with natural homogeneous media. The employments of the space rotations in the linear transformation processes allow the directed thermal diffusions to be independent of the geometric profiles, and the utilization of natural homogeneous media improve the feasibility. Four schemes, with fewer types of homogeneous media filling the functional regions, are demonstrated in transient states. The expected performances are observed in each scheme. The related performance are analyzed by comparing the thermal distribution characteristics and the illusion effectiveness on the measured lines. The findings obtained in this paper see applications in the development of directed diffusions with minimal thermal loss, used in novel “multi-beam” thermal generation, thermal lenses, solar receivers, and waveguide.

Some Einstein spaces and their global properties

International Nuclear Information System (INIS)

Siklos, S.T.C.

1981-01-01

The global structure of a class of Einstein spaces is investigated. These spaces have algebraically special Weyl tensors and contain homogeneous hypersurfaces. It is found that they display simple examples of a variety of interesting configuration involving horizons and singularities. (author)

A comparison of non-homogeneous Markov regression models with application to Alzheimer’s disease progression

Science.gov (United States)

Hubbard, R. A.; Zhou, X.H.

2011-01-01

Markov regression models are useful tools for estimating the impact of risk factors on rates of transition between multiple disease states. Alzheimer’s disease (AD) is an example of a multi-state disease process in which great interest lies in identifying risk factors for transition. In this context, non-homogeneous models are required because transition rates change as subjects age. In this report we propose a non-homogeneous Markov regression model that allows for reversible and recurrent disease states, transitions among multiple states between observations, and unequally spaced observation times. We conducted simulation studies to demonstrate performance of estimators for covariate effects from this model and compare performance with alternative models when the underlying non-homogeneous process was correctly specified and under model misspecification. In simulation studies, we found that covariate effects were biased if non-homogeneity of the disease process was not accounted for. However, estimates from non-homogeneous models were robust to misspecification of the form of the non-homogeneity. We used our model to estimate risk factors for transition to mild cognitive impairment (MCI) and AD in a longitudinal study of subjects included in the National Alzheimer’s Coordinating Center’s Uniform Data Set. Using our model, we found that subjects with MCI affecting multiple cognitive domains were significantly less likely to revert to normal cognition. PMID:22419833

Harnack inequality for harmonic functions relative to a nonlinear p-homogeneous Riemannian Dirichlet form

Directory of Open Access Journals (Sweden)

Marco Biroli

2007-12-01

Full Text Available We consider a measure valued map α(u defined on D where D is a subspace of L^p(X,m with X a locally compact Hausdorff topological space with a distance under which it is a space of homogeneous type. Under assumptions of convexity, Gateaux differentiability and other assumptions on α which generalize the properties of the energy measure of a Dirichlet form, we prove the Holder continuity of the local solution u of the problem  ∫Xµ(u,v(dx = 0  for each v belonging to a suitable space of test functions, where µ(u,v =< α'(u,v >.

Homogenization of resonant chiral metamaterials

OpenAIRE

Andryieuski, Andrei; Menzel, Christoph; Rockstuhl, Carsten; Malureanu, Radu; Lederer, Falk; Lavrinenko, Andrei

2010-01-01

Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as e.g. propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size a critical density exists above which increasing coupling between neighboring meta-atoms prevails a reasonable homogenization. On the contrary, a dilution in excess will induce features reminiscent to pho...

The complex structures on the coadjoint orbit spaces of Diff(S1) and on Bers' universal Teichmueller space are compatible

International Nuclear Information System (INIS)

Nag, S.; Verjovsky, A.

1988-08-01

Precisely two coadjoint orbit spaces of the group of string reparametrizations carry in a natural way the structure of infinite dimensional, holomorphically homogeneous complex manifolds. These are M 1 =Diff(S 1 )/Rot(S 1 ) and M 2 =Diff(S 1 )/Mo-barb(S 1 ). M 2 can be naturally considered as (embedded in) the classical univeral Teichmueller space T(Δ), simply by noting that a diffeomorphism of S 1 is a quasi-symmetric homeomorphism. T(Δ) is itself a homomorphically homogeneous complex Banach manifold. We prove that the inclusion of M 2 in T(Δ) is complex analytic. Every Teichmueller space of finite or infinite dimension is contained canonically and holomorphically in T(Δ). Our result thus appears to connect the loop space approach to bosonic string theory with the sum-over moduli (Polyakov path integral) approach. (author). 12 refs

Information Geometry Formalism for the Spatially Homogeneous Boltzmann Equation

Directory of Open Access Journals (Sweden)

Bertrand Lods

2015-06-01

Full Text Available Information Geometry generalizes to infinite dimension by modeling the tangent space of the relevant manifold of probability densities with exponential Orlicz spaces. We review here several properties of the exponential manifold on a suitable set Ɛ of mutually absolutely continuous densities. We study in particular the fine properties of the Kullback-Liebler divergence in this context. We also show that this setting is well-suited for the study of the spatially homogeneous Boltzmann equation if Ɛ is a set of positive densities with finite relative entropy with respect to the Maxwell density. More precisely, we analyze the Boltzmann operator in the geometric setting from the point of its Maxwell’s weak form as a composition of elementary operations in the exponential manifold, namely tensor product, conditioning, marginalization and we prove in a geometric way the basic facts, i.e., the H-theorem. We also illustrate the robustness of our method by discussing, besides the Kullback-Leibler divergence, also the property of Hyvärinen divergence. This requires us to generalize our approach to Orlicz–Sobolev spaces to include derivatives.

Half-width at half-maximum, full-width at half-maximum analysis

Indian Academy of Sciences (India)

addition to the well-defined parameter full-width at half-maximum (FWHM). The distribution of ... optical side-lobes in the diffraction pattern resulting in steep central maxima [6], reduc- tion of effects of ... and broad central peak. The idea of.

The dipoles reach the half-way mark

CERN Multimedia

2006-01-01

With the positioning of the 616th magnet, installation of the LHC dipoles has reached the half-way mark. Only half the dipoles remain to be installed! The 616th dipole out of a total of 1232 was installed at 3 a.m on Wednesday 12 July. Night and day, the tunnel is the setting for a never-ending series of carefully choreographed installation operations. At a rate of around twenty per week, there has been a steady underground flow of dipole magnets, each measuring 15 metres in length and weighing 34 tonnes. 'In order to recover the accumulated delays, installation is proceeding three times faster than planned', confides Claude Hauviller, who is supervising LHC installation. Four dipoles can be transported underground at the same time. It is a real challenge, which the 65-man team responsible for this difficult task faces on a daily basis. This is because there is very little space in the tunnel and there are no passing places for the magnet transport vehicles. The room for manoeuvre can sometimes be measured ...

Homogenization of neutronic diffusion models

International Nuclear Information System (INIS)

Capdebosq, Y.

1999-09-01

In order to study and simulate nuclear reactor cores, one needs to access the neutron distribution in the core. In practice, the description of this density of neutrons is given by a system of diffusion equations, coupled by non differential exchange terms. The strong heterogeneity of the medium constitutes a major obstacle to the numerical computation of this models at reasonable cost. Homogenization appears as compulsory. Heuristic methods have been developed since the origin by nuclear physicists, under a periodicity assumption on the coefficients. They consist in doing a fine computation one a single periodicity cell, to solve the system on the whole domain with homogeneous coefficients, and to reconstruct the neutron density by multiplying the solutions of the two computations. The objectives of this work are to provide mathematically rigorous basis to this factorization method, to obtain the exact formulas of the homogenized coefficients, and to start on geometries where two periodical medium are placed side by side. The first result of this thesis concerns eigenvalue problem models which are used to characterize the state of criticality of the reactor, under a symmetry assumption on the coefficients. The convergence of the homogenization process is proved, and formulas of the homogenized coefficients are given. We then show that without symmetry assumptions, a drift phenomenon appears. It is characterized by the mean of a real Bloch wave method, which gives the homogenized limit in the general case. These results for the critical problem are then adapted to the evolution model. Finally, the homogenization of the critical problem in the case of two side by side periodic medium is studied on a one dimensional on equation model. (authors)

Dynamic behavior of homogeneous and heterogeneous LMFBR core-design concepts

International Nuclear Information System (INIS)

Chang, Y.I.; Henryson, H. II; Orechwa, Y.; Su, S.F.; Greenman, G.; Blomquist, R.

1981-01-01

The emphasis is placed on obtaining an understanding of the inherent difference between homogeneous and heterogeneous core configurations regarding neutronic characteristics related to the dynamic behavior. The space-time neutronic and thermal-hydraulic behavior was analyzed in detail for various core configurations by using the FX2-TH, a two-dimensional kinetics code with thermal-hydraulic feedback. In addition, the relationship between the flux tilt and the fundamental-to-first harmonic eigenvalue separation, and the sodium void reactivity in heterogeneous cores were also sutdied

Orthogonality Measurement for Homogenous Projects-Bases

Science.gov (United States)

Ivan, Ion; Sandu, Andrei; Popa, Marius

2009-01-01

The homogenous projects-base concept is defined. Next, the necessary steps to create a homogenous projects-base are presented. A metric system is built, which then will be used for analyzing projects. The indicators which are meaningful for analyzing a homogenous projects-base are selected. The given hypothesis is experimentally verified. The…

Military Handbook: Management and Design Guidance Electromagnetic Radiation Hardness for Air Launched Ordnance Systems

Science.gov (United States)

1981-01-15

system is attacted to the delivery aircraft until it Impacto a target, it is exposed to electromagnetic radiation from emitters aboard the delivery...homogeneous, isotropic, ambient medium may be a lossy dielectric. Antenna computations include cur- rent distribution, input impedance, radiation...permissible ambient interference level in the system, and when determining the expected signal-to-inter- ference ratio of the signal transmission circuits

Analytical solutions of time-fractional models for homogeneous Gardner equation and non-homogeneous differential equations

Directory of Open Access Journals (Sweden)

Olaniyi Samuel Iyiola

2014-09-01

Full Text Available In this paper, we obtain analytical solutions of homogeneous time-fractional Gardner equation and non-homogeneous time-fractional models (including Buck-master equation using q-Homotopy Analysis Method (q-HAM. Our work displays the elegant nature of the application of q-HAM not only to solve homogeneous non-linear fractional differential equations but also to solve the non-homogeneous fractional differential equations. The presence of the auxiliary parameter h helps in an effective way to obtain better approximation comparable to exact solutions. The fraction-factor in this method gives it an edge over other existing analytical methods for non-linear differential equations. Comparisons are made upon the existence of exact solutions to these models. The analysis shows that our analytical solutions converge very rapidly to the exact solutions.

Hypersurface Homogeneous Cosmological Model in Modified Theory of Gravitation

Science.gov (United States)

Katore, S. D.; Hatkar, S. P.; Baxi, R. J.

2016-12-01

We study a hypersurface homogeneous space-time in the framework of the f (R, T) theory of gravitation in the presence of a perfect fluid. Exact solutions of field equations are obtained for exponential and power law volumetric expansions. We also solve the field equations by assuming the proportionality relation between the shear scalar (σ ) and the expansion scalar (θ ). It is observed that in the exponential model, the universe approaches isotropy at large time (late universe). The investigated model is notably accelerating and expanding. The physical and geometrical properties of the investigated model are also discussed.

TWO FERROMAGNETIC SPHERES IN HOMOGENEOUS MAGNETIC FIELD

Directory of Open Access Journals (Sweden)

Yury A. Krasnitsky

2018-01-01

Full Text Available The problem of two spherical conductors is studied quite in detail with bispherical coordinates usage and has numerous appendices in an electrostatics. The boundary-value problem about two ferromagnetic spheres enclosed on homogeneous and infinite environment in which the lack of spheres exists like homogeneous magnetic field is considered. The solution of Laplace's equation in the bispherical system of coordinates allows us to find the potential and field distribution in all spaces, including area between spheres. The boundary conditions in potential continuity and in ordinary density constituent of spheres surfaces induction flux are used. It is supposed that spheres are identical, and magnetic permeability of their material is expressed in  >> 0. The problem about falling of electromagnetic plane wave on the system of two spheres, which possesses electrically small sizes, can be considered as quasistationary. The scalar potentials received as a result of Laplace's equation solution are represented by the series containing Legendre polynomials. The concept of two spheres system effective permeability is introduced. It is equal to the advantage in magnitude of magnetic induction flux vector through a certain system’s section arising due to its magnetic properties. Necessary ratios for the effective permeability referred to the central system’s section are obtained. Particularly, the results can be used during the analysis of ferroxcube core clearance, which influences on the magnetic antenna properties. 

Internal homogenization: effective permittivity of a coated sphere.

Science.gov (United States)

Chettiar, Uday K; Engheta, Nader

2012-10-08

The concept of internal homogenization is introduced as a complementary approach to the conventional homogenization schemes, which could be termed as external homogenization. The theory for the internal homogenization of the permittivity of subwavelength coated spheres is presented. The effective permittivity derived from the internal homogenization of coreshells is discussed for plasmonic and dielectric constituent materials. The effective model provided by the homogenization is a useful design tool in constructing coated particles with desired resonant properties.

Homogenization methods for heterogeneous assemblies

International Nuclear Information System (INIS)

Wagner, M.R.

1980-01-01

The third session of the IAEA Technical Committee Meeting is concerned with the problem of homogenization of heterogeneous assemblies. Six papers will be presented on the theory of homogenization and on practical procedures for deriving homogenized group cross sections and diffusion coefficients. That the problem of finding so-called ''equivalent'' diffusion theory parameters for the use in global reactor calculations is of great practical importance. In spite of this, it is fair to say that the present state of the theory of second homogenization is far from being satisfactory. In fact, there is not even a uniquely accepted approach to the problem of deriving equivalent group diffusion parameters. Common agreement exists only about the fact that the conventional flux-weighting technique provides only a first approximation, which might lead to acceptable results in certain cases, but certainly does not guarantee the basic requirement of conservation of reaction rates

Time-Homogeneous Parabolic Wick-Anderson Model in One Space Dimension: Regularity of Solution

OpenAIRE

Kim, Hyun-Jung; Lototsky, Sergey V

2017-01-01

Even though the heat equation with random potential is a well-studied object, the particular case of time-independent Gaussian white noise in one space dimension has yet to receive the attention it deserves. The paper investigates the stochastic heat equation with space-only Gaussian white noise on a bounded interval. The main result is that the space-time regularity of the solution is the same for additive noise and for multiplicative noise in the Wick-It\\^o-Skorokhod interpretation.

Fast space-varying convolution using matrix source coding with applications to camera stray light reduction.

Science.gov (United States)

Wei, Jianing; Bouman, Charles A; Allebach, Jan P

2014-05-01

Many imaging applications require the implementation of space-varying convolution for accurate restoration and reconstruction of images. Here, we use the term space-varying convolution to refer to linear operators whose impulse response has slow spatial variation. In addition, these space-varying convolution operators are often dense, so direct implementation of the convolution operator is typically computationally impractical. One such example is the problem of stray light reduction in digital cameras, which requires the implementation of a dense space-varying deconvolution operator. However, other inverse problems, such as iterative tomographic reconstruction, can also depend on the implementation of dense space-varying convolution. While space-invariant convolution can be efficiently implemented with the fast Fourier transform, this approach does not work for space-varying operators. So direct convolution is often the only option for implementing space-varying convolution. In this paper, we develop a general approach to the efficient implementation of space-varying convolution, and demonstrate its use in the application of stray light reduction. Our approach, which we call matrix source coding, is based on lossy source coding of the dense space-varying convolution matrix. Importantly, by coding the transformation matrix, we not only reduce the memory required to store it; we also dramatically reduce the computation required to implement matrix-vector products. Our algorithm is able to reduce computation by approximately factoring the dense space-varying convolution operator into a product of sparse transforms. Experimental results show that our method can dramatically reduce the computation required for stray light reduction while maintaining high accuracy.

Gravity duals of half-BPS Wilson loops

International Nuclear Information System (INIS)

D'Hoker, Eric; Estes, John; Gutperle, Michael

2007-01-01

We explicitly construct the fully back-reacted half-BPS solutions in Type IIB supergravity which are dual to Wilson loops with 16 supersymmetries in N = 4 super Yang-Mills. In a first part, we use the methods of a companion paper to derive the exact general solution of the half-BPS equations on the space AdS 2 x S 2 x S 4 x Σ, with isometry group SO(2, 1) x SO(3) x SO(5) in terms of two locally harmonic functions on a Riemann surface Σ with boundary. These solutions, generally, have varying dilaton and axion, and non-vanishing 3-form fluxes. In a second part, we impose regularity and topology conditions. These non-singular solutions may be parametrized by a genus g ≥ 0 hyperelliptic surface Σ, all of whose branch points lie on the real line. Each genus g solution has only a single asymptotic AdS 5 x S 5 region, but exhibits g homology 3-spheres, and an extra g homology 5-spheres, carrying respectively RR 3-form and RR 5-form charges. For genus 0, we recover AdS 5 x S 5 with 3 free parameters, while for genus g ≥ 1, the solution has 2g+5 free parameters. The genus 1 case is studied in detail. Numerical analysis is used to show that the solutions are regular throughout the g = 1 parameter space. Collapse of a branch cut on Σ subtending either a homology 3-sphere or a homology 5-sphere is non-singular and yields the genus g-1 solution. This behavior is precisely expected of a proper dual to a Wilson loop in gauge theory

Classification of stationary compact homogeneous special pseudo K\\"ahler manifolds of semisimple groups

OpenAIRE

Alekseevsky, D. V.; Cortes, V.

1997-01-01

The variation of Hodge structure of a Calabi-Yau 3-fold induces a canonical K\\"ahler metric on its Kuranishi moduli space, known as the Weil-Petersson metric. Similarly, special pseudo K\\"ahler manifolds correspond to certain (abstract) variations of Hodge structure which generalize the above example. We give the classification of homogeneous special pseudo K\\"ahler manifolds of semisimple groups with compact stabilizer.

Homogeneous versus heterogeneous zeolite nucleation

NARCIS (Netherlands)

Dokter, W.H.; Garderen, van H.F.; Beelen, T.P.M.; Santen, van R.A.; Bras, W.

1995-01-01

Aggregates of fractal dimension were found in the intermediate gel phases that organize prior to nucleation and crystallization (shown right) of silicalite from a homogeneous reaction mixture. Small- and wide-angle X-ray scattering studies prove that for zeolites nucleation may be homogeneous or

Instabilities in dynamic anti-plane sliding of an elastic layer on a dissimilar elastic half-space

Science.gov (United States)

Kunnath, R.

2012-12-01

The stability of dynamic anti-plane sliding at an interface between an elastic layer and an elastic half-space with dissimilar elastic properties is studied. Friction at the interface is assumed to follow a rate- and state-dependent law, with a positive instantaneous dependence on slip velocity and a rate weakening behavior in the steady state. The perturbations are of the form exp(ikx+pt), where k is the wavenumber, x is the coordinate along the interface, p is the time response to the perturbation and t is time. The results of the stability analysis are shown in Figs. 1 and 2 with the velocity weakening parameter b/a=5, shear wave speed ratio cs'/cs=1.2, shear modulus ratio μ'/μ=1.2 and non-dimensional layer thickness H=100. The normalized instability growth rate and normalized phase velocity are plotted as a function of wavenumber. Fig.1 is for a non-dimensional unperturbed slip velocity ɛ=5 (rapid sliding) while Fig. 2 is for ɛ=0.05 (slow sliding). The results show the destabilization of interfacial waves. For slow sliding, destabilization of interfacial waves is still seen, indicating that the quasi-static approximation to slow sliding is not valid. This is in agreement with the result of Ranjith (Int. J. Solids and Struct., 2009, 46, 3086-3092) who predicted an instability of long-wavelength Love waves in slow sliding.

An explicit asymptotic model for the surface wave in a viscoelastic half-space based on applying Rabotnov's fractional exponential integral operators

Science.gov (United States)

Wilde, M. V.; Sergeeva, N. V.

2018-05-01

An explicit asymptotic model extracting the contribution of a surface wave to the dynamic response of a viscoelastic half-space is derived. Fractional exponential Rabotnov's integral operators are used for describing of material properties. The model is derived by extracting the principal part of the poles corresponding to the surface waves after applying Laplace and Fourier transforms. The simplified equations for the originals are written by using power series expansions. Padè approximation is constructed to unite short-time and long-time models. The form of this approximation allows to formulate the explicit model using a fractional exponential Rabotnov's integral operator with parameters depending on the properties of surface wave. The applicability of derived models is studied by comparing with the exact solutions of a model problem. It is revealed that the model based on Padè approximation is highly effective for all the possible time domains.

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.

Benchmarking homogenization algorithms for monthly data

Directory of Open Access Journals (Sweden)

V. K. C. Venema

2012-01-01

Full Text Available The COST (European Cooperation in Science and Technology Action ES0601: advances in homogenization methods of climate series: an integrated approach (HOME has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative. The algorithms were validated against a realistic benchmark dataset. The benchmark contains real inhomogeneous data as well as simulated data with inserted inhomogeneities. Random independent break-type inhomogeneities with normally distributed breakpoint sizes were added to the simulated datasets. To approximate real world conditions, breaks were introduced that occur simultaneously in multiple station series within a simulated network of station data. The simulated time series also contained outliers, missing data periods and local station trends. Further, a stochastic nonlinear global (network-wide trend was added.

Participants provided 25 separate homogenized contributions as part of the blind study. After the deadline at which details of the imposed inhomogeneities were revealed, 22 additional solutions were submitted. These homogenized datasets were assessed by a number of performance metrics including (i the centered root mean square error relative to the true homogeneous value at various averaging scales, (ii the error in linear trend estimates and (iii traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Contingency scores by themselves are not very informative. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve

GPM Level 3 IMERG Half Hourly 0.1 x 0.1 degree V03

Data.gov (United States)

National Aeronautics and Space Administration — This Directory Interchange Format (DIF) describes a collection of fields for the GPM Level 3 IMERG Final Half Hourly 0.1 x 0.1 degree V03 (GPM_3IMERGHH) at the NASA...

Vacancy induced half-metallicity in half-Heusler semiconductors

KAUST Repository

Zhu, Zhiyong

2011-09-28

First-principles calculations are performed to investigate the effect of vacancies on the electronic structure and magnetic properties of the two prototypical half-Heusler semiconductors NiTiSn and CoTiSb. The spin degeneracy of the host materials is broken for all types of isolated vacancies under consideration, except for Ni-deficient NiTiSn. A half-metallic character is identified in Sn-deficient NiTiSn and Co/Ti/Sb-deficient CoTiSb. We can explain our findings by introducing an extending Slater-Pauling rule for systems with defects. A ferromagnetic ordering of the local moments due to double exchange appears to be likely.

A second stage homogenization method

International Nuclear Information System (INIS)

Makai, M.

1981-01-01

A second homogenization is needed before the diffusion calculation of the core of large reactors. Such a second stage homogenization is outlined here. Our starting point is the Floquet theorem for it states that the diffusion equation for a periodic core always has a particular solution of the form esup(j)sup(B)sup(x) u (x). It is pointed out that the perturbation series expansion of function u can be derived by solving eigenvalue problems and the eigenvalues serve to define homogenized cross sections. With the help of these eigenvalues a homogenized diffusion equation can be derived the solution of which is cos Bx, the macroflux. It is shown that the flux can be expressed as a series of buckling. The leading term in this series is the well known Wigner-Seitz formula. Finally three examples are given: periodic absorption, a cell with an absorber pin in the cell centre, and a cell of three regions. (orig.)

Sewage sludge solubilization by high-pressure homogenization.

Science.gov (United States)

Zhang, Yuxuan; Zhang, Panyue; Guo, Jianbin; Ma, Weifang; Fang, Wei; Ma, Boqiang; Xu, Xiangzhe

2013-01-01

The behavior of sludge solubilization using high-pressure homogenization (HPH) treatment was examined by investigating the sludge solid reduction and organics solubilization. The sludge volatile suspended solids (VSS) decreased from 10.58 to 6.67 g/L for the sludge sample with a total solids content (TS) of 1.49% after HPH treatment at a homogenization pressure of 80 MPa with four homogenization cycles; total suspended solids (TSS) correspondingly decreased from 14.26 to 9.91 g/L. About 86.15% of the TSS reduction was attributed to the VSS reduction. The increase of homogenization pressure from 20 to 80 MPa or homogenization cycle number from 1 to 4 was favorable to the sludge organics solubilization, and the protein and polysaccharide solubilization linearly increased with the soluble chemical oxygen demand (SCOD) solubilization. More proteins were solubilized than polysaccharides. The linear relationship between SCOD solubilization and VSS reduction had no significant change under different homogenization pressures, homogenization cycles and sludge solid contents. The SCOD of 1.65 g/L was solubilized for the VSS reduction of 1.00 g/L for the three experimental sludge samples with a TS of 1.00, 1.49 and 2.48% under all HPH operating conditions. The energy efficiency results showed that the HPH treatment at a homogenization pressure of 30 MPa with a single homogenization cycle for the sludge sample with a TS of 2.48% was the most energy efficient.

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)

The Homogeneity Research of Urban Rail Transit Network Performance

Directory of Open Access Journals (Sweden)

Wang Fu-jian

2016-01-01

Full Text Available Urban Rail Transit is an important part of the public transit, it is necessary to carry out the corresponding network function analysis. Previous studies mainly about network performance analysis of a single city rail transit, lacking of horizontal comparison between the multi-city, it is difficult to find inner unity of different Urban Rail Transit network functions. Taking into account the Urban Rail Transit network is a typical complex networks, so this paper proposes the application of complex network theory to research the homogeneity of Urban Rail Transit network performance. This paper selects rail networks of Beijing, Shanghai, Guangzhou as calculation case, gave them a complex network mapping through the L, P Space method and had a static topological analysis using complex network theory, Network characteristics in three cities were calculated and analyzed form node degree distribution and node connection preference. Finally, this paper studied the network efficiency changes of Urban Rail Transit system under different attack mode. The results showed that, although rail transport network size, model construction and construction planning of the three cities are different, but their network performance in many aspects showed high homogeneity.

Surface half-metallicity of half-Heusler compound FeCrSe and interface half-metallicity of FeCrSe/GaP

Energy Technology Data Exchange (ETDEWEB)

Khalaf Al-zyadi, Jabbar M., E-mail: jabbar_alzyadi@yahoo.com [Department of Physics, College of Education for Pure Sciences, University of Basrah (Iraq); Jolan, Mudhahir H. [Department of Physics, College of Education for Pure Sciences, University of Basrah (Iraq); Yao, Kai-Lun, E-mail: klyao@mail.hust.edu.cn [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); International Center of Materials Physics, Chinese Academy of Sciences, Shenyang 110015 (China)

2016-04-01

Recent studies showed that half-Heusler FeCrSe exhibits half-metallic ferromagnetism (Huang et al. [20]). In this paper, we investigate extensively the electronic, magnetic, and half-metallic properties of the half-Heusler alloy FeCrSe (111) and (001) surfaces and the interface with GaP (111) substrate by using the first-principles calculations within the density functional theory. The atomic density of states demonstrates that the half-me tallicity verified in the bulk FeCrSe is maintained at the CrSe-terminated (001) and Se-terminated (111) surfaces, but lost at both Cr- and Fe-terminated (111) surfaces and the Fe-terminated (001) surface. Alternatively, for the interface of FeCrSe/GaP (111), the bulk half-metallicity is destroyed at Se–P configuration while Se–Ga interface and subinterface show nearly 100% spin polarization. Moreover, the calculated interfacial adhesion energies exhibit that Se–Ga shape is more stable than the Se–P one. The calculated magnetic moments of Se, Ga at the Se–Ga (111) interface and P at the Se–P (111) interface increase with respect to the corresponding bulk values while the atomic magnetic moment of Se atom at the Se–P (111) interface decreases. We also notice that the magnetic moments of subinterface Fe at both Se–Ga and Se–P (111) interfaces decrease compared to the bulk values. - Highlights: • The half-metallicity verified in the bulk FeCrSe is kept at the CrSe-terminated (001) and Se-terminated (111) surfaces. • The calculated interfacial adhesion energies exhibit that Se–Ga shape is more stable than Se–P. • The magnetic moments of Se, Ga and P atoms at the interface increase. • The Se–Ga interface shows nearly 100% spin polarization.

Space-Time Crystal and Space-Time Group.

Science.gov (United States)

Xu, Shenglong; Wu, Congjun

2018-03-02

Crystal structures and the Bloch theorem play a fundamental role in condensed matter physics. We extend the static crystal to the dynamic "space-time" crystal characterized by the general intertwined space-time periodicities in D+1 dimensions, which include both the static crystal and the Floquet crystal as special cases. A new group structure dubbed a "space-time" group is constructed to describe the discrete symmetries of a space-time crystal. Compared to space and magnetic groups, the space-time group is augmented by "time-screw" rotations and "time-glide" reflections involving fractional translations along the time direction. A complete classification of the 13 space-time groups in one-plus-one dimensions (1+1D) is performed. The Kramers-type degeneracy can arise from the glide time-reversal symmetry without the half-integer spinor structure, which constrains the winding number patterns of spectral dispersions. In 2+1D, nonsymmorphic space-time symmetries enforce spectral degeneracies, leading to protected Floquet semimetal states. We provide a general framework for further studying topological properties of the (D+1)-dimensional space-time crystal.

A literature review on biotic homogenization

OpenAIRE

Guangmei Wang; Jingcheng Yang; Chuangdao Jiang; Hongtao Zhao; Zhidong Zhang

2009-01-01

Biotic homogenization is the process whereby the genetic, taxonomic and functional similarity of two or more biotas increases over time. As a new research agenda for conservation biogeography, biotic homogenization has become a rapidly emerging topic of interest in ecology and evolution over the past decade. However, research on this topic is rare in China. Herein, we introduce the development of the concept of biotic homogenization, and then discuss methods to quantify its three components (...

Deformations of classical Lie algebras with homogeneous root system in characteristic two. I

International Nuclear Information System (INIS)

Chebochko, N G

2005-01-01

Spaces of local deformations of classical Lie algebras with a homogeneous root system over a field K of characteristic 2 are studied. By a classical Lie algebra over a field K we mean the Lie algebra of a simple algebraic Lie group or its quotient algebra by the centre. The description of deformations of Lie algebras is interesting in connection with the classification of the simple Lie algebras.

Homogeneity of small-scale earthquake faulting, stress, and fault strength

Science.gov (United States)

Hardebeck, J.L.

2006-01-01

Small-scale faulting at seismogenic depths in the crust appears to be more homogeneous than previously thought. I study three new high-quality focal-mechanism datasets of small (M angular difference between their focal mechanisms. Closely spaced earthquakes (interhypocentral distance homogeneous as well, to produce such similar earthquakes. Over larger length scales (???2-50 km), focal mechanisms become more diverse with increasing interhypocentral distance (differing on average by 40-70??). Mechanism variability on ???2- to 50 km length scales can be explained by ralatively small variations (???30%) in stress or fault strength. It is possible that most of this small apparent heterogeneity in stress of strength comes from measurement error in the focal mechanisms, as negligibble variation in stress or fault strength (<10%) is needed if each earthquake is assigned the optimally oriented focal mechanism within the 1-sigma confidence region. This local homogeneity in stress orientation and fault strength is encouraging, implying it may be possible to measure these parameters with enough precision to be useful in studying and modeling large earthquakes.

Assembly homogenization techniques for light water reactor analysis

International Nuclear Information System (INIS)

Smith, K.S.

1986-01-01

Recent progress in development and application of advanced assembly homogenization methods for light water reactor analysis is reviewed. Practical difficulties arising from conventional flux-weighting approximations are discussed and numerical examples given. The mathematical foundations for homogenization methods are outlined. Two methods, Equivalence Theory and Generalized Equivalence Theory which are theoretically capable of eliminating homogenization error are reviewed. Practical means of obtaining approximate homogenized parameters are presented and numerical examples are used to contrast the two methods. Applications of these techniques to PWR baffle/reflector homogenization and BWR bundle homogenization are discussed. Nodal solutions to realistic reactor problems are compared to fine-mesh PDQ calculations, and the accuracy of the advanced homogenization methods is established. Remaining problem areas are investigated, and directions for future research are suggested. (author)

Improving homogeneity by dynamic speed limit systems.

NARCIS (Netherlands)

Nes, N. van Brandenberg, S. & Twisk, D.A.M.

2010-01-01

Homogeneity of driving speeds is an important variable in determining road safety; more homogeneous driving speeds increase road safety. This study investigates the effect of introducing dynamic speed limit systems on homogeneity of driving speeds. A total of 46 subjects twice drove a route along 12

Mechanized syringe homogenization of human and animal tissues.

Science.gov (United States)

Kurien, Biji T; Porter, Andrew C; Patel, Nisha C; Kurono, Sadamu; Matsumoto, Hiroyuki; Scofield, R Hal

2004-06-01

Tissue homogenization is a prerequisite to any fractionation schedule. A plethora of hands-on methods are available to homogenize tissues. Here we report a mechanized method for homogenizing animal and human tissues rapidly and easily. The Bio-Mixer 1200 (manufactured by Innovative Products, Inc., Oklahoma City, OK) utilizes the back-and-forth movement of two motor-driven disposable syringes, connected to each other through a three-way stopcock, to homogenize animal or human tissue. Using this method, we were able to homogenize human or mouse tissues (brain, liver, heart, and salivary glands) in 5 min. From sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and a matrix-assisted laser desorption/ionization time-of-flight mass spectrometric enzyme assay for prolidase, we have found that the homogenates obtained were as good or even better than that obtained used a manual glass-on-Teflon (DuPont, Wilmington, DE) homogenization protocol (all-glass tube and Teflon pestle). Use of the Bio-Mixer 1200 to homogenize animal or human tissue precludes the need to stay in the cold room as is the case with the other hands-on homogenization methods available, in addition to freeing up time for other experiments.

Homogeneity and thermodynamic identities in geometrothermodynamics

Energy Technology Data Exchange (ETDEWEB)

Quevedo, Hernando [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares (Mexico); Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); ICRANet, Rome (Italy); Quevedo, Maria N. [Universidad Militar Nueva Granada, Departamento de Matematicas, Facultad de Ciencias Basicas, Bogota (Colombia); Sanchez, Alberto [CIIDET, Departamento de Posgrado, Queretaro (Mexico)

2017-03-15

We propose a classification of thermodynamic systems in terms of the homogeneity properties of their fundamental equations. Ordinary systems correspond to homogeneous functions and non-ordinary systems are given by generalized homogeneous functions. This affects the explicit form of the Gibbs-Duhem relation and Euler's identity. We show that these generalized relations can be implemented in the formalism of black hole geometrothermodynamics in order to completely fix the arbitrariness present in Legendre invariant metrics. (orig.)

Quantum group gauge theory on quantum spaces

International Nuclear Information System (INIS)

Brzezinski, T.; Majid, S.

1993-01-01

We construct quantum group-valued canonical connections on quantum homogeneous spaces, including a q-deformed Dirac monopole on the quantum sphere of Podles quantum differential coming from the 3-D calculus of Woronowicz on SU q (2). The construction is presented within the setting of a general theory of quantum principal bundles with quantum group (Hopf algebra) fiber, associated quantum vector bundles and connection one-forms. Both the base space (spacetime) and the total space are non-commutative algebras (quantum spaces). (orig.)

Vision-21: Space Travel for the Next Millennium

International Nuclear Information System (INIS)

Landis, G.A.

1990-04-01

The papers from this symposium, that was held at the NASA Lewis Research Center on April 3-4, 1990, are presented. The theme selected for the symposium was space travel for the next millennium. It was hoped that the participants would allow their focus to consider possible advances in technologies for space travel not just for currently envisioned projects, but for possibilities beyond the next generation and the next thousand years. About half of the contributed papers focussed on propulsion and the other half on other issues related to space travel

Homogeneity of Prototypical Attributes in Soccer Teams

Directory of Open Access Journals (Sweden)

Christian Zepp

2015-09-01

Full Text Available Research indicates that the homogeneous perception of prototypical attributes influences several intragroup processes. The aim of the present study was to describe the homogeneous perception of the prototype and to identify specific prototypical subcategories, which are perceived as homogeneous within sport teams. The sample consists of N = 20 soccer teams with a total of N = 278 athletes (age M = 23.5 years, SD = 5.0 years. The results reveal that subcategories describing the cohesiveness of the team and motivational attributes are mentioned homogeneously within sport teams. In addition, gender, identification, team size, and the championship ranking significantly correlate with the homogeneous perception of prototypical attributes. The results are discussed on the basis of theoretical and practical implications.

Time-domain single-source integral equations for analyzing scattering from homogeneous penetrable objects

KAUST Repository

Valdés, Felipe

2013-03-01

Single-source time-domain electric-and magnetic-field integral equations for analyzing scattering from homogeneous penetrable objects are presented. Their temporal discretization is effected by using shifted piecewise polynomial temporal basis functions and a collocation testing procedure, thus allowing for a marching-on-in-time (MOT) solution scheme. Unlike dual-source formulations, single-source equations involve space-time domain operator products, for which spatial discretization techniques developed for standalone operators do not apply. Here, the spatial discretization of the single-source time-domain integral equations is achieved by using the high-order divergence-conforming basis functions developed by Graglia alongside the high-order divergence-and quasi curl-conforming (DQCC) basis functions of Valdés The combination of these two sets allows for a well-conditioned mapping from div-to curl-conforming function spaces that fully respects the space-mapping properties of the space-time operators involved. Numerical results corroborate the fact that the proposed procedure guarantees accuracy and stability of the MOT scheme. © 2012 IEEE.

Author Details

African Journals Online (AJOL)

) - Articles Propagation of shear waves in an irregular magnetoelastic monoclinic layer sandwiched between two isotropic half-spaces ... Propagation of S-waves in a non-homogeneous anisotropic incompressible and initially stressed medium

Homogenization theory in reactor lattices

International Nuclear Information System (INIS)

Benoist, P.

1986-02-01

The purpose of the theory of homogenization of reactor lattices is to determine, by the mean of transport theory, the constants of a homogeneous medium equivalent to a given lattice, which allows to treat the reactor as a whole by diffusion theory. In this note, the problem is presented by laying emphasis on simplicity, as far as possible [fr

Enhancement of anaerobic sludge digestion by high-pressure homogenization.

Science.gov (United States)

Zhang, Sheng; Zhang, Panyue; Zhang, Guangming; Fan, Jie; Zhang, Yuxuan

2012-08-01

To improve anaerobic sludge digestion efficiency, the effects of high-pressure homogenization (HPH) conditions on the anaerobic sludge digestion were investigated. The VS and TCOD were significantly removed with the anaerobic digestion, and the VS removal and TCOD removal increased with increasing the homogenization pressure and homogenization cycle number; correspondingly, the accumulative biogas production also increased with increasing the homogenization pressure and homogenization cycle number. The optimal homogenization pressure was 50 MPa for one homogenization cycle and 40 MPa for two homogenization cycles. The SCOD of the sludge supernatant significantly increased with increasing the homogenization pressure and homogenization cycle number due to the sludge disintegration. The relationship between the biogas production and the sludge disintegration showed that the accumulative biogas and methane production were mainly enhanced by the sludge disintegration, which accelerated the anaerobic digestion process and improved the methane content in the biogas. Copyright © 2012 Elsevier Ltd. All rights reserved.

Layered Fiberconcrete with Non-Homogeneous Fibers Distribution

OpenAIRE

Lūsis, V; Krasņikovs, A

2013-01-01

The aim of present research is to create fiberconcrete construction with non-homogeneous fibers distribution in it. Traditionally fibers are homogeneously dispersed in a concrete. At the same time in many situations fiberconcretes with homogeneously dispersed fibers are not optimal (majority of added fibers are not participating in a loads bearing process).

Radiotracer investigation of cement raw meal homogenizers. Pt. 2

International Nuclear Information System (INIS)

Baranyai, L.

1983-01-01

Based on radioisotopic tracer technique a method has been worked out to study the homogenization and segregation processes of cement-industrial raw meal homogenizers. On-site measurements were carried out by this method in some Hungarian cement works to determine the optimal homogenization parameters of operating homogenizers. The motion and distribution of different raw meal fractions traced with 198 Au radioisotope was studied in homogenization processes proceeding with different parameters. In the first part of the publication the change of charge homogenity in time was discussed which had been measured as the resultant of mixing and separating processes. In the second part the parameters and types of homogenizers influencing the efficiency of homogenization have been detailed. (orig.) [de

Radiotracer investigation of cement raw meal homogenizers. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Baranyai, L

1983-12-01

Based on radioisotopic tracer technique a method has been worked out to study the homogenization and segregation processes of cement-industrial raw meal homogenizers. On-site measurements were carried out by this method in some Hungarian cement works to determine the optimal homogenization parameters of operating homogenizers. The motion and distribution of different raw meal fractions traced with /sup 198/Au radioisotope was studied in homogenization processes proceeding with different parameters. In the first part of the publication the change of charge homogenity in time was discussed which had been measured as the resultant of mixing and separating processes. In the second part the parameters and types of homogenizers influencing the efficiency of homogenization have been detailed.

A method to improve the B0 homogeneity of the heart in vivo.

Science.gov (United States)

Jaffer, F A; Wen, H; Balaban, R S; Wolff, S D

1996-09-01

A homogeneous static (B0) magnetic field is required for many NMR experiments such as echo planar imaging, localized spectroscopy, and spiral scan imaging. Although semi-automated techniques have been described to improve the B0 field homogeneity, none has been applied to the in vivo heart. The acquisition of cardiac field maps is complicated by motion, blood flow, and chemical shift artifact from epicardial fat. To overcome these problems, an ungated three-dimensional (3D) chemical shift image (CSI) was collected to generate a time and motion-averaged B0 field map. B0 heterogeneity in the heart was minimized by using a previous algorithm that solves for the optimal shim coil currents for an input field map, using up to third-order current-bounded shims (1). The method improved the B0 homogenelty of the heart in all 11 normal volunteers studied. After application of the algorithm to the unshimmed cardiac field maps, the standard deviation of proton frequency decreased by 43%, the magnitude 1H spectral linewidth decreased by 24%, and the peak-peak gradient decreased by 35%. Simulations of the high-order (second- and third-order) shims in B0 field correction of the heart show that high order shims are important, resulting for nearly half of the improvement in homogeneity for several subjects. The T2* of the left ventricular anterior wall before and after field correction was determined at 4.0 Tesis. Finally, results show that cardiac shimming is of benefit in cardiac 31P NMR spectroscopy and cardiac echo planar imaging.

Half-Space Temperature Field with a Movable Thermally Thin-Coated Boundary Under External Heat Flux

Directory of Open Access Journals (Sweden)

P. A. Vlasov

2014-01-01

Full Text Available In engineering practice analytical methods of the mathematical theory of heat conduction hold a special place. This is due to many reasons, in particular, because of the fact that the solutions of the relevant problems represented in analytically closed form, can be used not only for a parametric analysis of the studied temperature field and to explore the specific features of its formation, but also to test the developed computational algorithms, which are aimed at solving real-world application heat and mass transfer problems. Difficulties arising when using the analytical mathematical theory methods of heat conduction in practice are well known. Also they are significantly exacerbated if the boundaries of the system under study are movable, even in the simplest case, when the law of motion is known.The main goal of the conducted research is to have an analytically closed-form problem solution for finding the orthotropic half-space temperature field, a boundary of which has thermally thin coating exposed to extremely concentrated stationary external heat flux and uniformly moves parallel to itself.The assumption that the covering of the boundary is thermally thin, allowed to realize the idea of \\concentrated capacity", that is to accept the hypothesis that the mean-thickness coating temperature is equal to the temperature of its boundaries. This assumption allowed us to reduce the problem under consideration to a mixed problem for a parabolic equation with a specific boundary condition.The Hankel integral transform of zero order with respect to the radial variable and the Laplace transform with respect to the temporal variable were used to solve the reduced problem. These techniques have allowed us to submit the required solution as an iterated integral.

Homogenization approach in engineering

International Nuclear Information System (INIS)

Babuska, I.

1975-10-01

Homogenization is an approach which studies the macrobehavior of a medium by its microproperties. Problems with a microstructure play an essential role in such fields as mechanics, chemistry, physics, and reactor engineering. Attention is concentrated on a simple specific model problem to illustrate results and problems typical of the homogenization approach. Only the diffusion problem is treated here, but some statements are made about the elasticity of composite materials. The differential equation is solved for linear cases with and without boundaries and for the nonlinear case. 3 figures, 1 table

Genetic Homogenization of Composite Materials

Directory of Open Access Journals (Sweden)

P. Tobola

2009-04-01

Full Text Available The paper is focused on numerical studies of electromagnetic properties of composite materials used for the construction of small airplanes. Discussions concentrate on the genetic homogenization of composite layers and composite layers with a slot. The homogenization is aimed to reduce CPU-time demands of EMC computational models of electrically large airplanes. First, a methodology of creating a 3-dimensional numerical model of a composite material in CST Microwave Studio is proposed focusing on a sufficient accuracy of the model. Second, a proper implementation of a genetic optimization in Matlab is discussed. Third, an association of the optimization script and a simplified 2-dimensional model of the homogeneous equivalent model in Comsol Multiphysics is proposed considering EMC issues. Results of computations are experimentally verified.

Microstructural evolution during the homogenization heat treatment of 6XXX and 7XXX aluminum alloys

Science.gov (United States)

Priya, Pikee

Homogenization heat treatment of as-cast billets is an important step in the processing of aluminum extrusions. Microstructural evolution during homogenization involves elimination of the eutectic morphology by spheroidisation of the interdendritic phases, minimization of the microsegregation across the grains through diffusion, dissolution of the low-melting phases, which enhances the surface finish of the extrusions, and precipitation of nano-sized dispersoids (for Cr-, Zr-, Mn-, Sc-containing alloys), which inhibit grain boundary motion to prevent recrystallization. Post-homogenization cooling reprecipitates some of the phases, changing the flow stress required for subsequent extrusion. These precipitates, however, are deleterious for the mechanical properties of the alloy and also hamper the age-hardenability and are hence dissolved during solution heat treatment. Microstructural development during homogenization and subsequent cooling occurs both at the length scale of the Secondary Dendrite Arm Spacing (SDAS) in micrometers and dispersoids in nanometers. Numerical tools to simulate microstructural development at both the length scales have been developed and validated against experiments. These tools provide easy and convenient means to study the process. A Cellular Automaton-Finite Volume-based model for evolution of interdendritic phases is coupled with a Particle Size Distribution-based model for precipitation of dispersoids across the grain. This comprehensive model has been used to study the effect of temperature, composition, as-cast microstructure, and cooling rates during post-homogenization quenching on microstructural evolution. The numerical study has been complimented with experiments involving Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction and Differential Scanning Calorimetry and a good agreement has with numerical results has been found. The current work aims to study the microstructural evolution during

Stimulus homogeneity enhances implicit learning: evidence from contextual cueing.

Science.gov (United States)

Feldmann-Wüstefeld, Tobias; Schubö, Anna

2014-04-01

Visual search for a target object is faster if the target is embedded in a repeatedly presented invariant configuration of distractors ('contextual cueing'). It has also been shown that the homogeneity of a context affects the efficiency of visual search: targets receive prioritized processing when presented in a homogeneous context compared to a heterogeneous context, presumably due to grouping processes at early stages of visual processing. The present study investigated in three Experiments whether context homogeneity also affects contextual cueing. In Experiment 1, context homogeneity varied on three levels of the task-relevant dimension (orientation) and contextual cueing was most pronounced for context configurations with high orientation homogeneity. When context homogeneity varied on three levels of the task-irrelevant dimension (color) and orientation homogeneity was fixed, no modulation of contextual cueing was observed: high orientation homogeneity led to large contextual cueing effects (Experiment 2) and low orientation homogeneity led to low contextual cueing effects (Experiment 3), irrespective of color homogeneity. Enhanced contextual cueing for homogeneous context configurations suggest that grouping processes do not only affect visual search but also implicit learning. We conclude that memory representation of context configurations are more easily acquired when context configurations can be processed as larger, grouped perceptual units. However, this form of implicit perceptual learning is only improved by stimulus homogeneity when stimulus homogeneity facilitates grouping processes on a dimension that is currently relevant in the task. Copyright © 2014 Elsevier B.V. All rights reserved.

A study of the homogeneous stages in the catalytic oxidation of naphthalene, o-xylene, and benzene over a vibratory-fluidized catalyst bed

Energy Technology Data Exchange (ETDEWEB)

Korneichuk, G P; Stasevich, V P; Shaprinskaya, T M; Girushtin, G G; Gritsenko, V I; Zelenchukova, T G

1978-01-01

To identify the conditions for minimizing homogeneous states, the reaction kinetics were studied in a vibrating gradientless quartz reactor both in the presence and absence of the catalyst. A tenfold decrease of the reactional space in the absence of catalyst inhibited the oxidation (e.g., from a 68% conversion to 10% at 500/sup 0/C for o-xylene, and from 100% to 2% at 580/sup 0/C for benzene), whereas increasing the surface-volume ratio of the reactor increased the oxidation rate for benzene, which indicated that noncatalytic oxidation follows a radical-chain mechanism and involves both homogeneous (mainly) and heterogeneous stages. Catalytic oxidation carried out in a small volume (to avoid the homogeneous states) followed a heterogeneous mechanism up to 580/sup 0/C for naphthalene and o-xylene, and up to 550/sup 0/C for benzene. At higher temperatures, however, volume oxidation of benzene to carbon oxides was detected, which was favored by intense reactor vibration (i.e., increasing free space between catalyst grains), constituted 27% at 564/sup 0/C and 40% at 584/sup 0/C, and probably followed a heterogeneous-homogeneous mechanism. The partial oxidation products (i.e., phthalic and (for benzene) maleic anhydride) formed entirely by a heterogeneous mechanism. Tables and graphs.

STRESS DISTRIBUTION IN THE STRATIFIED MASS CONTAINING VERTICAL ALVEOLE

Directory of Open Access Journals (Sweden)

Bobileva Tatiana Nikolaevna

2017-08-01

Full Text Available Almost all subsurface rocks used as foundations for various types of structures are stratified. Such heterogeneity may cause specific behaviour of the materials under strain. Differential equations describing the behaviour of such materials contain rapidly fluctuating coefficients, in view of this, solution of such equations is more time-consuming when using today’s computers. The method of asymptotic averaging leads to getting homogeneous medium under study to averaged equations with fixed factors. The present article is concerned with stratified soil mass consisting of pair-wise alternative isotropic elastic layers. In the results of elastic modules averaging, the present soil mass with horizontal rock stratification is simulated by homogeneous transversal-isotropic half-space with isotropy plane perpendicular to the standing axis. Half-space is loosened by a vertical alveole of circular cross-section, and virgin ground is under its own weight. For horizontal parting planes of layers, the following two types of surface conditions are set: ideal contact and backlash without cleavage. For homogeneous transversal-isotropic half-space received with a vertical alveole, the analytical solution of S.G. Lekhnitsky, well known in scientific papers, is used. The author gives expressions for stress components and displacements in soil mass for different marginal conditions on the alveole surface. Such research problems arise when constructing and maintaining buildings and when composite materials are used.

An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

DEFF Research Database (Denmark)

Legeais, Jean-Francois; Ablain, Michael; Zawadzki, Lionel

2018-01-01

, the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed...... to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter...

Multilevel Monte Carlo Approaches for Numerical Homogenization

KAUST Repository

Efendiev, Yalchin R.

2015-10-01

In this article, we study the application of multilevel Monte Carlo (MLMC) approaches to numerical random homogenization. Our objective is to compute the expectation of some functionals of the homogenized coefficients, or of the homogenized solutions. This is accomplished within MLMC by considering different sizes of representative volumes (RVEs). Many inexpensive computations with the smallest RVE size are combined with fewer expensive computations performed on larger RVEs. Likewise, when it comes to homogenized solutions, different levels of coarse-grid meshes are used to solve the homogenized equation. We show that, by carefully selecting the number of realizations at each level, we can achieve a speed-up in the computations in comparison to a standard Monte Carlo method. Numerical results are presented for both one-dimensional and two-dimensional test-cases that illustrate the efficiency of the approach.

Spontaneous formation and dynamics of half-skyrmions in a chiral liquid-crystal film

Science.gov (United States)

Nych, Andriy; Fukuda, Jun-Ichi; Ognysta, Uliana; Žumer, Slobodan; Muševič, Igor

2017-12-01

Skyrmions are coreless vortex-like excitations emerging in diverse condensed-matter systems, and real-time observation of their dynamics is still challenging. Here we report the first direct optical observation of the spontaneous formation of half-skyrmions. In a thin film of a chiral liquid crystal, depending on experimental conditions including film thickness, they form a hexagonal lattice whose lattice constant is a few hundred nanometres, or appear as isolated entities with topological defects compensating their charge. These half-skyrmions exhibit intriguing dynamical behaviour driven by thermal fluctuations. Numerical calculations of real-space images successfully corroborate the experimental observations despite the challenge because of the characteristic scale of the structures close to the optical resolution limit. A thin film of a chiral liquid crystal thus offers an intriguing platform that facilitates a direct investigation of the dynamics of topological excitations such as half-skyrmions and their manipulation with optical techniques.

Homogeneous M2 duals

International Nuclear Information System (INIS)

Figueroa-O’Farrill, José; Ungureanu, Mara

2016-01-01

Motivated by the search for new gravity duals to M2 branes with N>4 supersymmetry — equivalently, M-theory backgrounds with Killing superalgebra osp(N|4) for N>4 — we classify (except for a small gap) homogeneous M-theory backgrounds with symmetry Lie algebra so(n)⊕so(3,2) for n=5,6,7. We find that there are no new backgrounds with n=6,7 but we do find a number of new (to us) backgrounds with n=5. All backgrounds are metrically products of the form AdS 4 ×P 7 , with P riemannian and homogeneous under the action of SO(5), or S 4 ×Q 7 with Q lorentzian and homogeneous under the action of SO(3,2). At least one of the new backgrounds is supersymmetric (albeit with only N=2) and we show that it can be constructed from a supersymmetric Freund-Rubin background via a Wick rotation. Two of the new backgrounds have only been approximated numerically.

Homogeneous M2 duals

Energy Technology Data Exchange (ETDEWEB)

Figueroa-O’Farrill, José [School of Mathematics and Maxwell Institute for Mathematical Sciences,The University of Edinburgh,James Clerk Maxwell Building, The King’s Buildings, Peter Guthrie Tait Road,Edinburgh EH9 3FD, Scotland (United Kingdom); Ungureanu, Mara [Humboldt-Universität zu Berlin, Institut für Mathematik,Unter den Linden 6, 10099 Berlin (Germany)

2016-01-25

Motivated by the search for new gravity duals to M2 branes with N>4 supersymmetry — equivalently, M-theory backgrounds with Killing superalgebra osp(N|4) for N>4 — we classify (except for a small gap) homogeneous M-theory backgrounds with symmetry Lie algebra so(n)⊕so(3,2) for n=5,6,7. We find that there are no new backgrounds with n=6,7 but we do find a number of new (to us) backgrounds with n=5. All backgrounds are metrically products of the form AdS{sub 4}×P{sup 7}, with P riemannian and homogeneous under the action of SO(5), or S{sup 4}×Q{sup 7} with Q lorentzian and homogeneous under the action of SO(3,2). At least one of the new backgrounds is supersymmetric (albeit with only N=2) and we show that it can be constructed from a supersymmetric Freund-Rubin background via a Wick rotation. Two of the new backgrounds have only been approximated numerically.

Elastic full waveform inversion based on the homogenization method: theoretical framework and 2-D numerical illustrations

Science.gov (United States)

Capdeville, Yann; Métivier, Ludovic

2018-05-01

Seismic imaging is an efficient tool to investigate the Earth interior. Many of the different imaging techniques currently used, including the so-called full waveform inversion (FWI), are based on limited frequency band data. Such data are not sensitive to the true earth model, but to a smooth version of it. This smooth version can be related to the true model by the homogenization technique. Homogenization for wave propagation in deterministic media with no scale separation, such as geological media, has been recently developed. With such an asymptotic theory, it is possible to compute an effective medium valid for a given frequency band such that effective waveforms and true waveforms are the same up to a controlled error. In this work we make the link between limited frequency band inversion, mainly FWI, and homogenization. We establish the relation between a true model and an FWI result model. This relation is important for a proper interpretation of FWI images. We numerically illustrate, in the 2-D case, that an FWI result is at best the homogenized version of the true model. Moreover, it appears that the homogenized FWI model is quite independent of the FWI parametrization, as long as it has enough degrees of freedom. In particular, inverting for the full elastic tensor is, in each of our tests, always a good choice. We show how the homogenization can help to understand FWI behaviour and help to improve its robustness and convergence by efficiently constraining the solution space of the inverse problem.

Phenotypic Changes Exhibited by E. coli Cultured in Space

DEFF Research Database (Denmark)

Zea, Luis; Larsen, Michael; Estante, Frederico

2017-01-01

% in space with respect to the Earth control group. Outer membrane vesicles were observed on the spaceflight samples, but not on the Earth cultures. While E. coli suspension cultures on Earth were homogenously distributed throughout the liquid medium, in space they tended to form a cluster, leaving...

Hybrid design method for air-core solenoid with axial homogeneity

Energy Technology Data Exchange (ETDEWEB)

Huang, Li; Lee, Sang Jin [Uiduk University, Gyeongju (Korea, Republic of); Choi, Suk Jin [Institute for Basic Science, Daejeon (Korea, Republic of)

2016-03-15

In this paper, a hybrid method is proposed to design an air-core superconducting solenoid system for 6 T axial uniform magnetic field using Niobium Titanium (NbTi) superconducting wire. In order to minimize the volume of conductor, the hybrid optimization method including a linear programming and a nonlinear programming was adopted. The feasible space of solenoid is divided by several grids and the magnetic field at target point is approximated by the sum of magnetic field generated by an ideal current loop at the center of each grid. Using the linear programming, a global optimal current distribution in the feasible space can be indicated by non-zero current grids. Furthermore the clusters of the non-zero current grids also give the information of probable solenoids in the feasible space, such as the number, the shape, and so on. Applying these probable solenoids as the initial model, the final practical configuration of solenoids with integer layers can be obtained by the nonlinear programming. The design result illustrates the efficiency and the flexibility of the hybrid method. And this method can also be used for the magnet design which is required the high homogeneity within several ppm (parts per million)

Two-Dimensional Homogeneous Fermi Gases

Science.gov (United States)

Hueck, Klaus; Luick, Niclas; Sobirey, Lennart; Siegl, Jonas; Lompe, Thomas; Moritz, Henning

2018-02-01

We report on the experimental realization of homogeneous two-dimensional (2D) Fermi gases trapped in a box potential. In contrast to harmonically trapped gases, these homogeneous 2D systems are ideally suited to probe local as well as nonlocal properties of strongly interacting many-body systems. As a first benchmark experiment, we use a local probe to measure the density of a noninteracting 2D Fermi gas as a function of the chemical potential and find excellent agreement with the corresponding equation of state. We then perform matter wave focusing to extract the momentum distribution of the system and directly observe Pauli blocking in a near unity occupation of momentum states. Finally, we measure the momentum distribution of an interacting homogeneous 2D gas in the crossover between attractively interacting fermions and bosonic dimers.

Diffusion piecewise homogenization via flux discontinuity ratios

International Nuclear Information System (INIS)

Sanchez, Richard; Dante, Giorgio; Zmijarevic, Igor

2013-01-01

We analyze piecewise homogenization with flux-weighted cross sections and preservation of averaged currents at the boundary of the homogenized domain. Introduction of a set of flux discontinuity ratios (FDR) that preserve reference interface currents leads to preservation of averaged region reaction rates and fluxes. We consider the class of numerical discretizations with one degree of freedom per volume and per surface and prove that when the homogenization and computing meshes are equal there is a unique solution for the FDRs which exactly preserve interface currents. For diffusion sub-meshing we introduce a Jacobian-Free Newton-Krylov method and for all cases considered obtain an 'exact' numerical solution (eight digits for the interface currents). The homogenization is completed by extending the familiar full assembly homogenization via flux discontinuity factors to the sides of regions laying on the boundary of the piecewise homogenized domain. Finally, for the familiar nodal discretization we numerically find that the FDRs obtained with no sub-mesh (nearly at no cost) can be effectively used for whole-core diffusion calculations with sub-mesh. This is not the case, however, for cell-centered finite differences. (authors)

Discrete symmetries and coset space dimensional reduction

International Nuclear Information System (INIS)

Kapetanakis, D.; Zoupanos, G.

1989-01-01

We consider the discrete symmetries of all the six-dimensional coset spaces and we apply them in gauge theories defined in ten dimensions which are dimensionally reduced over these homogeneous spaces. Particular emphasis is given in the consequences of the discrete symmetries on the particle content as well as on the symmetry breaking a la Hosotani of the resulting four-dimensional theory. (orig.)

Conversion of the Amazon rainforest to agriculture results in biotic homogenization of soil bacterial communities.

Science.gov (United States)

Rodrigues, Jorge L M; Pellizari, Vivian H; Mueller, Rebecca; Baek, Kyunghwa; Jesus, Ederson da C; Paula, Fabiana S; Mirza, Babur; Hamaoui, George S; Tsai, Siu Mui; Feigl, Brigitte; Tiedje, James M; Bohannan, Brendan J M; Nüsslein, Klaus

2013-01-15

The Amazon rainforest is the Earth's largest reservoir of plant and animal diversity, and it has been subjected to especially high rates of land use change, primarily to cattle pasture. This conversion has had a strongly negative effect on biological diversity, reducing the number of plant and animal species and homogenizing communities. We report here that microbial biodiversity also responds strongly to conversion of the Amazon rainforest, but in a manner different from plants and animals. Local taxonomic and phylogenetic diversity of soil bacteria increases after conversion, but communities become more similar across space. This homogenization is driven by the loss of forest soil bacteria with restricted ranges (endemics) and results in a net loss of diversity. This study shows homogenization of microbial communities in response to human activities. Given that soil microbes represent the majority of biodiversity in terrestrial ecosystems and are intimately involved in ecosystem functions, we argue that microbial biodiversity loss should be taken into account when assessing the impact of land use change in tropical forests.

Homogeneous deuterium exchange using rhenium and platinum chloride catalysts

International Nuclear Information System (INIS)

Fawdry, R.M.

1979-01-01

Previous studies of homogeneous hydrogen isotope exchange are mostly confined to one catalyst, the tetrachloroplatinite salt. Recent reports have indicated that chloride salts of iridium and rhodium may also be homogeneous exchange catalysts similar to the tetrachloroplatinite, but with much lower activities. Exchange by these homogeneous catalysts is frequently accompanied by metal precipitation with the termination of homogeneous exchange, particularly in the case of alkane exchange. The studies presented in this thesis describe two different approaches to overcome this limitation of homogeneous hydrogen isotope exchange catalysts. The first approach was to improve the stability of an existing homogeneous catalyst and the second was to develop a new homogeneous exchange catalyst which is free of the instability limitation

Investigations into homogenization of electromagnetic metamaterials

DEFF Research Database (Denmark)

Clausen, Niels Christian Jerichau

This dissertation encompasses homogenization methods, with a special interest into their applications to metamaterial homogenization. The first method studied is the Floquet-Bloch method, that is based on the assumption of a material being infinite periodic. Its field can then be expanded in term...

Development of a Practical Hydrogen Storage System Based on Liquid Organic Hydrogen Carriers and a Homogeneous Catalyst

Energy Technology Data Exchange (ETDEWEB)

Jensen, Craig [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Brayton, Daniel [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Jorgensen, Scott W. [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.; Hou, Peter [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.

2017-03-24

The objectives of this project were: 1) optimize a hydrogen storage media based on LOC/homogeneous pincer catalyst (carried out at Hawaii Hydrogen Carriers, LLC) and 2) develop space, mass and energy efficient tank and reactor system to house and release hydrogen from the media (carried out at General Motor Research Center).

Vacancy induced half-metallicity in half-Heusler semiconductors

KAUST Repository

Zhu, Zhiyong; Cheng, Yingchun; Schwingenschlö gl, Udo

2011-01-01

First-principles calculations are performed to investigate the effect of vacancies on the electronic structure and magnetic properties of the two prototypical half-Heusler semiconductors NiTiSn and CoTiSb. The spin degeneracy of the host materials

Homogeneous Studies of Transiting Extrasolar Planets: Current Status and Future Plans

Science.gov (United States)

Taylor, John

2011-09-01

We now know of over 500 planets orbiting stars other than our Sun. The jewels in the crown are the transiting planets, for these are the only ones whose masses and radii are measurable. They are fundamental for our understanding of the formation, evolution, structure and atmospheric properties of extrasolar planets. However, their characterization is not straightforward, requiring extremely high-precision photometry and spectroscopy as well as input from theoretical stellar models. I summarize the motivation and current status of a project to measure the physical properties of all known transiting planetary systems using homogeneous techniques (Southworth 2008, 2009, 2010, 2011 in preparation). Careful attention is paid to the treatment of limb darkening, contaminating light, correlated noise, numerical integration, orbital eccentricity and orientation, systematic errors from theoretical stellar models, and empirical constraints. Complete error budgets are calculated for each system and can be used to determine which type of observation would be most useful for improving the parameter measurements. Known correlations between the orbital periods, masses, surface gravities, and equilibrium temperatures of transiting planets can be explored more safely due to the homogeneity of the properties. I give a sneak preview of Homogeneous Studies Paper 4, which includes the properties of thirty transiting planetary systems observed by the CoRoT, Kepler and Deep Impact space missions. Future opportunities are discussed, plus remaining problems with our understanding of transiting planets. I acknowledge funding from the UK STFC in the form of an Advanced Fellowship.

Stability of geodesic imcompleteness for Robertson-Walker space-times

International Nuclear Information System (INIS)

Beem, J.K.

1981-01-01

Let (M,g) be a Lorentzian warped product space-time M = (a, b) X H,g = -dt 2 x fh, where -infinity -infinity and (H,h) is homogeneous, then the past incompleteness of every timelike geodesic of (M,g) is stable under small C 0 perturbations in the space Lor(M) of Lorentzian metrics for M. Also it is shown that if (H,h) is isotropic and (M,g) contains a past-inextendible, past-incomplete null geodesic, then the past incompleteness of all null geodesics is stable under small C 1 perturbations in Lor(M). Given either the isotropy or homogeneity of the Riemannian factor, the background space-time (M,g) is globally hyperbolic. The results of this paper, in particular, answer a question raised by D. Lerner for big bang Robertson-Walker cosmological models affirmatively. (author)

7 CFR 51.2295 - Half kernel.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Half kernel. 51.2295 Section 51.2295 Agriculture... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2295 Half kernel. Half kernel means the separated half of a kernel with not more than one-eighth broken off. ...

An Efficient Numerical Method for Computing Synthetic Seismograms for a Layered Half-space with Sources and Receivers at Close or Same Depths

Science.gov (United States)

Zhang, H.-m.; Chen, X.-f.; Chang, S.

- It is difficult to compute synthetic seismograms for a layered half-space with sources and receivers at close to or the same depths using the generalized R/T coefficient method (Kennett, 1983; Luco and Apsel, 1983; Yao and Harkrider, 1983; Chen, 1993), because the wavenumber integration converges very slowly. A semi-analytic method for accelerating the convergence, in which part of the integration is implemented analytically, was adopted by some authors (Apsel and Luco, 1983; Hisada, 1994, 1995). In this study, based on the principle of the Repeated Averaging Method (Dahlquist and Björck, 1974; Chang, 1988), we propose an alternative, efficient, numerical method, the peak-trough averaging method (PTAM), to overcome the difficulty mentioned above. Compared with the semi-analytic method, PTAM is not only much simpler mathematically and easier to implement in practice, but also more efficient. Using numerical examples, we illustrate the validity, accuracy and efficiency of the new method.

Non-homogeneous dynamic Bayesian networks for continuous data

NARCIS (Netherlands)

Grzegorczyk, Marco; Husmeier, Dirk

Classical dynamic Bayesian networks (DBNs) are based on the homogeneous Markov assumption and cannot deal with non-homogeneous temporal processes. Various approaches to relax the homogeneity assumption have recently been proposed. The present paper presents a combination of a Bayesian network with

Dynamic half-rate connections in GSM

NARCIS (Netherlands)

Winands, E.M.M.; Wieland, J.; Sanders, B.

2006-01-01

Dynamic half-rate is an optional feature that allows a Global System for Mobile communication (GSM) cell to switch new incoming half-rate capable calls to half-rate speech coding, when the cell is nearly congested. Since two half-rate speech calls can be put together in one single-time slot, dynamic

Elastic Wave Control Beyond Band-Gaps: Shaping the Flow of Waves in Plates and Half-Spaces with Subwavelength Resonant Rods

Directory of Open Access Journals (Sweden)

Andrea Colombi

2017-08-01

Full Text Available In metamaterial science, local resonance and hybridization are key phenomena strongly influencing the dispersion properties; the metasurface discussed in this article created by a cluster of resonators, subwavelength rods, atop an elastic surface being an exemplar with these features. On this metasurface, band-gaps, slow or fast waves, negative refraction, and dynamic anisotropy can all be observed by exploring frequencies and wavenumbers from the Floquet–Bloch problem and by using the Brillouin zone. These extreme characteristics, when appropriately engineered, can be used to design and control the propagation of elastic waves along the metasurface. For the exemplar we consider, two parameters are easily tuned: rod height and cluster periodicity. The height is directly related to the band-gap frequency and, hence, to the slow and fast waves, while the periodicity is related to the appearance of dynamic anisotropy. Playing with these two parameters generates a gallery of metasurface designs to control the propagation of both flexural waves in plates and surface Rayleigh waves for half-spaces. Scalability with respect to the frequency and wavelength of the governing physical laws allows the application of these concepts in very different fields and over a wide range of lengthscales.

Homogenization of High-Contrast Brinkman Flows

KAUST Repository

Brown, Donald L.

2015-04-16

Modeling porous flow in complex media is a challenging problem. Not only is the problem inherently multiscale but, due to high contrast in permeability values, flow velocities may differ greatly throughout the medium. To avoid complicated interface conditions, the Brinkman model is often used for such flows [O. Iliev, R. Lazarov, and J. Willems, Multiscale Model. Simul., 9 (2011), pp. 1350--1372]. Instead of permeability variations and contrast being contained in the geometric media structure, this information is contained in a highly varying and high-contrast coefficient. In this work, we present two main contributions. First, we develop a novel homogenization procedure for the high-contrast Brinkman equations by constructing correctors and carefully estimating the residuals. Understanding the relationship between scales and contrast values is critical to obtaining useful estimates. Therefore, standard convergence-based homogenization techniques [G. A. Chechkin, A. L. Piatniski, and A. S. Shamev, Homogenization: Methods and Applications, Transl. Math. Monogr. 234, American Mathematical Society, Providence, RI, 2007, G. Allaire, SIAM J. Math. Anal., 23 (1992), pp. 1482--1518], although a powerful tool, are not applicable here. Our second point is that the Brinkman equations, in certain scaling regimes, are invariant under homogenization. Unlike in the case of Stokes-to-Darcy homogenization [D. Brown, P. Popov, and Y. Efendiev, GEM Int. J. Geomath., 2 (2011), pp. 281--305, E. Marusic-Paloka and A. Mikelic, Boll. Un. Mat. Ital. A (7), 10 (1996), pp. 661--671], the results presented here under certain velocity regimes yield a Brinkman-to-Brinkman upscaling that allows using a single software platform to compute on both microscales and macroscales. In this paper, we discuss the homogenized Brinkman equations. We derive auxiliary cell problems to build correctors and calculate effective coefficients for certain velocity regimes. Due to the boundary effects, we construct

A personal view on homogenization

International Nuclear Information System (INIS)

Tartar, L.

1987-02-01

The evolution of some ideas is first described. Under the name homogenization are collected all the mathematical results who help understanding the relations between the microstructure of a material and its macroscopic properties. Homogenization results are given through a critically detailed bibliography. The mathematical models given are systems of partial differential equations, supposed to describe some properties at a scale ε and we want to understand what will happen to the solutions if ε tends to 0

A strong open mapping theorem for surjections from cones onto Banach spaces

NARCIS (Netherlands)

Jeu, de M.F.E.; Messerschmidt, H.J.M.

2014-01-01

We show that a continuous additive positively homogeneous map from a closed not necessarily proper cone in a Banach space onto a Banach space is an open map precisely when it is surjective. This generalization of the usual Open Mapping Theorem for Banach spaces is then combined with Michael's

Campground marketing: the heavy-half strategy

Science.gov (United States)

Wilbur F. LaPage

1969-01-01

When we arrayed camping frequencies in order from the lowest to the highest number of days spent camping per year we found that half of the campers do much more than half of the camping. Campers in this heavy half consistently camp more, year after year, and are increasing their annual participation as well. Heavy-half campers have larger investments in camping...

Indium tin oxide refractometer in the visible and near infrared via lossy mode and surface plasmon resonances with Kretschmann configuration

International Nuclear Information System (INIS)

Torres, V.; Beruete, M.; Sánchez, P.; Del Villar, I.

2016-01-01

An indium tin oxide (ITO) refractometer based on the generation of lossy mode resonances (LMRs) and surface plasmon resonances (SPRs) is presented. Both LMRs and SPRs are excited, in a single setup, under grazing angle incidence with Kretschmann configuration in an ITO thin-film deposited on a glass slide. The sensing capabilities of the device are demonstrated using several solutions of glycerin and water with refractive indices ranging from 1.33 to 1.47. LMRs are excited in the visible range, from 617 nm to 682 nm under TE polarization and from 533 nm to 637 nm under TM polarization, with a maximum sensitivity of 700 nm/RIU and 1200 nm/RIU, respectively. For the SPRs, a sensing range between 1375 nm and 2494 nm with a maximum sensitivity of 8300 nm/RIU is measured under TM polarization. Experimental results are supported with numerical simulations based on a modification of the plane-wave method for a one-dimensional multilayer waveguide

Indium tin oxide refractometer in the visible and near infrared via lossy mode and surface plasmon resonances with Kretschmann configuration

Energy Technology Data Exchange (ETDEWEB)

Torres, V. [Antenna Group–TERALAB, Public University of Navarra, 31006 Pamplona (Spain); Beruete, M. [Antenna Group–TERALAB, Public University of Navarra, 31006 Pamplona (Spain); Institute of Smart Cities, Public University of Navarra, 31006 Pamplona (Spain); Sánchez, P. [Department of Electric and Electronic Engineering, Public University of Navarra, Pamplona 31006 (Spain); Del Villar, I. [Institute of Smart Cities, Public University of Navarra, 31006 Pamplona (Spain); Department of Electric and Electronic Engineering, Public University of Navarra, Pamplona 31006 (Spain)

2016-01-25

An indium tin oxide (ITO) refractometer based on the generation of lossy mode resonances (LMRs) and surface plasmon resonances (SPRs) is presented. Both LMRs and SPRs are excited, in a single setup, under grazing angle incidence with Kretschmann configuration in an ITO thin-film deposited on a glass slide. The sensing capabilities of the device are demonstrated using several solutions of glycerin and water with refractive indices ranging from 1.33 to 1.47. LMRs are excited in the visible range, from 617 nm to 682 nm under TE polarization and from 533 nm to 637 nm under TM polarization, with a maximum sensitivity of 700 nm/RIU and 1200 nm/RIU, respectively. For the SPRs, a sensing range between 1375 nm and 2494 nm with a maximum sensitivity of 8300 nm/RIU is measured under TM polarization. Experimental results are supported with numerical simulations based on a modification of the plane-wave method for a one-dimensional multilayer waveguide.

Homogeneous turbulence dynamics

CERN Document Server

Sagaut, Pierre

2018-01-01

This book provides state-of-the-art results and theories in homogeneous turbulence, including anisotropy and compressibility effects with extension to quantum turbulence, magneto-hydodynamic turbulence  and turbulence in non-newtonian fluids. Each chapter is devoted to a given type of interaction (strain, rotation, shear, etc.), and presents and compares experimental data, numerical results, analysis of the Reynolds stress budget equations and advanced multipoint spectral theories. The role of both linear and non-linear mechanisms is emphasized. The link between the statistical properties and the dynamics of coherent structures is also addressed. Despite its restriction to homogeneous turbulence, the book is of interest to all people working in turbulence, since the basic physical mechanisms which are present in all turbulent flows are explained. The reader will find a unified presentation of the results and a clear presentation of existing controversies. Special attention is given to bridge the results obta...

Rayleigh waves in elastic medium with double porosity

Directory of Open Access Journals (Sweden)

Rajneesh KUMAR

2018-03-01

Full Text Available The present paper deals with the propagation of Rayleigh waves in isotropic homogeneous elastic half-space with double porosity whose surface is subjected to stress-free boundary conditions. The compact secular equations for elastic solid half-space with voids are deduced as special cases from the present analysis. In order to illustrate the analytical developments, the secular equations have been solved numerically. The computer simulated results for copper materials in respect of Rayleigh wave velocity and attenuation coe¢ cient have been presented graphically.

From stochastic phase space evolution to Brownian motion in collective space

International Nuclear Information System (INIS)

Benhassine, B.; Farine, M.; Hernandez, E.S.; Idier, D.; Remaud, B.; Sebille, F.

1993-01-01

Within the framework of stochastic transport equations in phase space, the dynamics of fluctuations on collective variables in homogeneous fermion systems is studied. The transport coefficients are formally deduced in the relaxation time approximation and a general method to compute dynamically the dispersions of collective observables is proposed as a set of coupled equations. Independently, the general covariance matrix of phase space fluctuations and the dispersion on collective variables at equilibrium are derived. Detailed numerical applications show that dynamics of fluctuations can be extracted from noisy numerical simulations and that the leading parameter for collective fluctuations is the excitation energy whatever is its degree of thermalization. (authors). 16 refs., 12 figs

A generalized model for homogenized reflectors

International Nuclear Information System (INIS)

Pogosbekyan, Leonid; Kim, Yeong Il; Kim, Young Jin; Joo, Hyung Kook

1996-01-01

A new concept of equivalent homogenization is proposed. The concept employs new set of homogenized parameters: homogenized cross sections (XS) and interface matrix (IM), which relates partial currents at the cell interfaces. The idea of interface matrix generalizes the idea of discontinuity factors (DFs), proposed and developed by K. Koebke and K. Smith. The method of K. Smith can be simulated within framework of new method, while the new method approximates hetero-geneous cell better in case of the steep flux gradients at the cell interfaces. The attractive shapes of new concept are:improved accuracy, simplicity of incorporation in the existing codes, equal numerical expenses in comparison to the K. Smith's approach. The new concept is useful for: (a) explicit reflector/baffle simulation; (b)control blades simulation; (c) mixed UO 2 /MOX core simulation. The offered model has been incorporated in the finite difference code and in the nodal code PANBOX. The numerical results show good accuracy of core calculations and insensitivity of homogenized parameters with respect to in-core conditions

An Advanced VHF/UHF Short Range, Groundwave Propagation Model for Paths With Near-Earth Antennas

National Research Council Canada - National Science Library

Cross, Marshall W; Fung, Tat Y

2006-01-01

... the earth such as: Unattended Ground Sensors (UGS) and Intelligent Munitions Systems (IMS), are attenuated above free space values by the lossy earth itself and any obstructions between a transmitter and receiver pair...

Dissolution test for homogeneity of mixed oxide fuel pellets

International Nuclear Information System (INIS)

Lerch, R.E.

1979-08-01

Experiments were performed to determine the relationship between fuel pellet homogeneity and pellet dissolubility. Although, in general, the amount of pellet residue decreased with increased homogeneity, as measured by the pellet figure of merit, the relationship was not absolute. Thus, all pellets with high figure of merit (excellent homogeneity) do not necessarily dissolve completely and all samples that dissolve completely do not necessarily have excellent homogeneity. It was therefore concluded that pellet dissolubility measurements could not be substituted for figure of merit determinations as a measurement of pellet homogeneity. 8 figures, 3 tables

Radon transformation on reductive symmetric spaces:Support theorems

DEFF Research Database (Denmark)

Kuit, Job Jacob

2013-01-01

We introduce a class of Radon transforms for reductive symmetric spaces, including the horospherical transforms, and derive support theorems for these transforms. A reductive symmetric space is a homogeneous space G/H for a reductive Lie group G of the Harish-Chandra class, where H is an open sub...... is based on the relation between the Radon transform and the Fourier transform on G/H, and a Paley–Wiener-shift type argument. Our results generalize the support theorem of Helgason for the Radon transform on a Riemannian symmetric space....

Homogenization patterns of the world's freshwater fish faunas.

Science.gov (United States)

Villéger, Sébastien; Blanchet, Simon; Beauchard, Olivier; Oberdorff, Thierry; Brosse, Sébastien

2011-11-01

The world is currently undergoing an unprecedented decline in biodiversity, which is mainly attributable to human activities. For instance, nonnative species introduction, combined with the extirpation of native species, affects biodiversity patterns, notably by increasing the similarity among species assemblages. This biodiversity change, called taxonomic homogenization, has rarely been assessed at the world scale. Here, we fill this gap by assessing the current homogenization status of one of the most diverse vertebrate groups (i.e., freshwater fishes) at global and regional scales. We demonstrate that current homogenization of the freshwater fish faunas is still low at the world scale (0.5%) but reaches substantial levels (up to 10%) in some highly invaded river basins from the Nearctic and Palearctic realms. In these realms experiencing high changes, nonnative species introductions rather than native species extirpations drive taxonomic homogenization. Our results suggest that the "Homogocene era" is not yet the case for freshwater fish fauna at the worldwide scale. However, the distressingly high level of homogenization noted for some biogeographical realms stresses the need for further understanding of the ecological consequences of homogenization processes.

Homogen Mur - et udviklingsprojekt

DEFF Research Database (Denmark)

Dahl, Torben; Beim, Anne; Sørensen, Peter

1997-01-01

Mølletorvet i Slagelse er det første byggeri i Danmark, hvor ydervæggen er udført af homogene bærende og isolerende teglblokke. Byggeriet viser en række af de muligheder, der både med hensyn til konstruktioner, energiforhold og arkitektur ligger i anvendelsen af homogent blokmurværk.......Mølletorvet i Slagelse er det første byggeri i Danmark, hvor ydervæggen er udført af homogene bærende og isolerende teglblokke. Byggeriet viser en række af de muligheder, der både med hensyn til konstruktioner, energiforhold og arkitektur ligger i anvendelsen af homogent blokmurværk....

Planar half-cell shaped precursor body

DEFF Research Database (Denmark)

2015-01-01

The invention relates to a half-cell shaped precursor body of either anode type or cathode type, the half-cell shaped precursor body being prepared to be free sintered to form a sintered or pre-sintered half-cell being adapted to be stacked in a solid oxide fuel cell stack. The obtained half......-cell has an improved planar shape, which remains planar also after a sintering process and during temperature fluctuations....

Homogeneous solutions of stationary Navier-Stokes equations with isolated singularities on the unit sphere. II. Classification of axisymmetric no-swirl solutions

Science.gov (United States)

Li, Li; Li, YanYan; Yan, Xukai

2018-05-01

We classify all (- 1)-homogeneous axisymmetric no-swirl solutions of incompressible stationary Navier-Stokes equations in three dimension which are smooth on the unit sphere minus the south and north poles, parameterizing them as a four dimensional surface with boundary in appropriate function spaces. Then we establish smoothness properties of the solution surface in the four parameters. The smoothness properties will be used in a subsequent paper where we study the existence of (- 1)-homogeneous axisymmetric solutions with non-zero swirl on S2 ∖ { S , N }, emanating from the four dimensional solution surface.

Projection of the rotation form Navier-Stokes equation onto the half-staggered grid

Energy Technology Data Exchange (ETDEWEB)

Cho, Ji Ryong [Inje University, Kimhae (Korea, Republic of)

2016-07-15

A projection method for computing incompressible fluid flow is proposed. For the method, the rotation form Navier-Stokes equation (NSE), for which the velocity and the total pressure are employed, is discretized on the half-staggered, finite difference spatial grid. The total pressure couples the static pressure gradient and the convection of momentum in the continuous NSE while the half-staggered grid provides weak pressure-velocity coupling in discrete space. These two features interact synergistically for the discretized NSE to produce smooth pressure fields without additional numerical artifacts such as the momentum interpolation. The method preserves the kinetic energy at the inviscid limit condition. Numerical solutions of the decaying Taylor vortex, the inviscid Taylor vortex, the sudden expansion channel and the square-prism wake are presented.

Inverse scale space decomposition

DEFF Research Database (Denmark)

Schmidt, Marie Foged; Benning, Martin; Schönlieb, Carola-Bibiane

2018-01-01

We investigate the inverse scale space flow as a decomposition method for decomposing data into generalised singular vectors. We show that the inverse scale space flow, based on convex and even and positively one-homogeneous regularisation functionals, can decompose data represented...... by the application of a forward operator to a linear combination of generalised singular vectors into its individual singular vectors. We verify that for this decomposition to hold true, two additional conditions on the singular vectors are sufficient: orthogonality in the data space and inclusion of partial sums...... of the subgradients of the singular vectors in the subdifferential of the regularisation functional at zero. We also address the converse question of when the inverse scale space flow returns a generalised singular vector given that the initial data is arbitrary (and therefore not necessarily in the range...

Half-time strategies to enhance second-half performance in team-sports players: a review and recommendations.

Science.gov (United States)

Russell, Mark; West, Daniel J; Harper, Liam D; Cook, Christian J; Kilduff, Liam P

2015-03-01

A number of intermittent team sports require that two consecutive periods of play (lasting for ~30-45 min) are separated by a 10-20 min half-time break. The half-time practices employed by team-sports players generally include returning to the changing rooms, temporarily relaxing from the cognitive and physical demands of the first half, rehydration and re-fuelling strategies, addressing injury or equipment concerns, and receiving tactical instruction and coach feedback. However, the typically passive nature of these actions has been associated with physiological changes that impair performance during the second half. Both physical and cognitive performances have been found to decline in the initial stages of subsequent exercise that follows half-time. An increased risk of injury has also been observed during this period. Therefore, half-time provides sports scientists and strength and conditioning coaches with an opportunity to optimise second-half performance. An overview of strategies thought to benefit team-sports athletes is presented; specifically, the efficacy of heat maintenance strategies (including passive and active methods), post-activation potentiation, hormonal priming, and modified hydro-nutritional practices are discussed. A theoretical model of applying these strategies in a manner that compliments current practice is also offered.

Synchronous Half-Wave Rectifier

Science.gov (United States)

Rippel, Wally E.

1989-01-01

Synchronous rectifying circuit behaves like diode having unusually low voltage drop during forward-voltage half cycles. Circuit particularly useful in power supplies with potentials of 5 Vdc or less, where normal forward-voltage drops in ordinary diodes unacceptably large. Fabricated as monolithic assembly or as hybrid. Synchronous half-wave rectifier includes active circuits to attain low forward voltage drop and high rectification efficiency.

Finite-size scaling of the entanglement entropy of the quantum Ising chain with homogeneous, periodically modulated and random couplings

International Nuclear Information System (INIS)

Iglói, Ferenc; Lin, Yu-Cheng

2008-01-01

Using free-fermionic techniques we study the entanglement entropy of a block of contiguous spins in a large finite quantum Ising chain in a transverse field, with couplings of different types: homogeneous, periodically modulated and random. We carry out a systematic study of finite-size effects at the quantum critical point, and evaluate subleading corrections both for open and for periodic boundary conditions. For a block corresponding to a half of a finite chain, the position of the maximum of the entropy as a function of the control parameter (e.g. the transverse field) can define the effective critical point in the finite sample. On the basis of homogeneous chains, we demonstrate that the scaling behavior of the entropy near the quantum phase transition is in agreement with the universality hypothesis, and calculate the shift of the effective critical point, which has different scaling behaviors for open and for periodic boundary conditions

At-tank Low-Activity Feed Homogeneity Analysis Verification

International Nuclear Information System (INIS)

DOUGLAS, J.G.

2000-01-01

This report evaluates the merit of selecting sodium, aluminum, and cesium-137 as analytes to indicate homogeneity of soluble species in low-activity waste (LAW) feed and recommends possible analytes and physical properties that could serve as rapid screening indicators for LAW feed homogeneity. The three analytes are adequate as screening indicators of soluble species homogeneity for tank waste when a mixing pump is used to thoroughly mix the waste in the waste feed staging tank and when all dissolved species are present at concentrations well below their solubility limits. If either of these conditions is violated, then the three indicators may not be sufficiently chemically representative of other waste constituents to reliably indicate homogeneity in the feed supernatant. Additional homogeneity indicators that should be considered are anions such as fluoride, sulfate, and phosphate, total organic carbon/total inorganic carbon, and total alpha to estimate the transuranic species. Physical property measurements such as gamma profiling, conductivity, specific gravity, and total suspended solids are recommended as possible at-tank methods for indicating homogeneity. Indicators of LAW feed homogeneity are needed to reduce the U.S. Department of Energy, Office of River Protection (ORP) Program's contractual risk by assuring that the waste feed is within the contractual composition and can be supplied to the waste treatment plant within the schedule requirements

Radiance intensity enhanced by thin inhomogeneous lossy films

International Nuclear Information System (INIS)

Ben-Abdallah, Philippe; Ni Bo

2004-01-01

Basically, the classical radiative transfer theory assumes that the coherent component of the radiation field is equal to zero and heuristic considerations about energy conservation are used in the phenomenological derivation of the RTE. Here a self-consistent theory is presented to investigate radiative transport in the presence of diffraction processes within thin inhomogeneous films. The problem of linear optics about the transport of scalar radiation within film is solved, a new definition of the radiance is introduced in agreement with earlier definitions and a corresponding radiative transfer equation is derived. The influence of spatial variations of the bulk properties on the propagating mode is described in detail. It is analytically predicted that, unlike homogeneous media, an inhomogeneous film can enhance the radiance intensity in spite of the diffraction and the local extinction. From a practical point of view, the results of this work should be useful to perform the optimal design for many thermoelectric devices such as the new generations of photovoltaiec cells

Verification of homogenization in fast critical assembly analyses

International Nuclear Information System (INIS)

Chiba, Go

2006-01-01

In the present paper, homogenization procedures for fast critical assembly analyses are investigated. Errors caused by homogenizations are evaluated by the exact perturbation theory. In order to obtain reference solutions, three-dimensional plate-wise transport calculations are performed. It is found that the angular neutron flux along plate boundaries has a significant peak in the fission source energy range. To treat this angular dependence accurately, the double-Gaussian Chebyshev angular quadrature set with S 24 is applied. It is shown that the difference between the heterogeneous leakage theory and the homogeneous theory is negligible, and that transport cross sections homogenized with neutron flux significantly underestimate neutron leakage. The error in criticality caused by a homogenization is estimated at about 0.1%Δk/kk' in a small fast critical assembly. In addition, the neutron leakage is overestimated by both leakage theories when sodium plates in fuel lattices are voided. (author)

Cosmic homogeneity: a spectroscopic and model-independent measurement

Science.gov (United States)

Gonçalves, R. S.; Carvalho, G. C.; Bengaly, C. A. P., Jr.; Carvalho, J. C.; Bernui, A.; Alcaniz, J. S.; Maartens, R.

2018-03-01

Cosmology relies on the Cosmological Principle, i.e. the hypothesis that the Universe is homogeneous and isotropic on large scales. This implies in particular that the counts of galaxies should approach a homogeneous scaling with volume at sufficiently large scales. Testing homogeneity is crucial to obtain a correct interpretation of the physical assumptions underlying the current cosmic acceleration and structure formation of the Universe. In this letter, we use the Baryon Oscillation Spectroscopic Survey to make the first spectroscopic and model-independent measurements of the angular homogeneity scale θh. Applying four statistical estimators, we show that the angular distribution of galaxies in the range 0.46 < z < 0.62 is consistent with homogeneity at large scales, and that θh varies with redshift, indicating a smoother Universe in the past. These results are in agreement with the foundations of the standard cosmological paradigm.

A Modified Homogeneous Balance Method and Its Applications

International Nuclear Information System (INIS)

Liu Chunping

2011-01-01

A modified homogeneous balance method is proposed by improving some key steps in the homogeneous balance method. Bilinear equations of some nonlinear evolution equations are derived by using the modified homogeneous balance method. Generalized Boussinesq equation, KP equation, and mKdV equation are chosen as examples to illustrate our method. This approach is also applicable to a large variety of nonlinear evolution equations. (general)

Multilevel Monte Carlo Approaches for Numerical Homogenization

KAUST Repository

Efendiev, Yalchin R.; Kronsbein, Cornelia; Legoll, Fré dé ric

2015-01-01

it comes to homogenized solutions, different levels of coarse-grid meshes are used to solve the homogenized equation. We show that, by carefully selecting the number of realizations at each level, we can achieve a speed-up in the computations in comparison

Internal electric fields of electrolytic solutions induced by space-charge polarization

Science.gov (United States)

Sawada, Atsushi

2006-10-01

The dielectric dispersion of electrolytic solutions prepared using chlorobenzene as a solvent and tetrabutylammonium tetraphenylborate as a solute is analyzed in terms of space-charge polarization in order to derive the ionic constants, and the Stokes radius obtained is discussed in comparison with the values that have been measured by conductometry. A homogeneous internal electric field is assumed for simplicity in the analysis of the space-charge polarization. The justification of the approximation by the homogeneous field is discussed from two points of view: one is the accuracy of the Stokes radius value observed and the other is the effect of bound charges on electrodes in which they level the highly inhomogeneous field, which has been believed in the past. In order to investigate the actual electric field, numerical calculations based on the Poisson equation are carried out by considering the influence of the bound charges. The variation of the number of bound charges with time is clarified by determining the relaxation function of the dielectric constant attributed to the space-charge polarization. Finally, a technique based on a two-field approximation, where homogeneous and hyperbolic fields are independently applied in relevant frequency ranges, is introduced to analyze the space-charge polarization of the electrolytic solutions, and further improvement of the accuracy in the determination of the Stokes radius is achieved.

From stochastic phase-space evolution to brownian motion in collective space

Energy Technology Data Exchange (ETDEWEB)

Benhassine, B. (Lab. de Physique Nucleaire/ CNRS et Univ. de Nantes, 44 Nantes (France)); Farine, M. (Lab. de Physique Nucleaire/ CNRS et Univ. de Nantes, 44 Nantes (France) Ecole Navale, Lamveoc-Loulmic, 29 Brest-Naval (France)); Hernandez, E.S. (Dept. de Fisica - Facultad de Ciencias Exactas y Naturales, Univ. de Buenos Aires (Argentina)); Idier, D. (Lab. de Physique Nucleaire/ CNRS et Univ. de Nantes, 44 Nantes (France)); Remaud, B. (Lab. de Physique Nucleaire/ CNRS et Univ. de Nantes, 44 Nantes (France)); Sebille, F. (Lab. de Physique Nucleaire/ CNRS et Univ. de Nantes, 44 Nantes (France))

1994-01-24

Within the framework of stochastic transport equations in phase space, we study the dynamics of fluctuations on collective variables in homogeneous fermion systems. The transport coefficients are formally deduced in the relaxation-time approximation and a general method to compute dynamically the dispersions of collective observables is proposed as a set of coupled equations: respectively, the BUU/Landau-Vlasov equation for the average phase-space trajectories and the equations for the averages and dispersions of the observables. Independently, we derive the general covariance matrix of phase-space fluctuations and then by projection, the dispersion on collective variables at equilibrium. Detailed numerical applications of the formalism are given; they show that the dynamics of fluctuations can be extracted from noisy numerical simulations and that the leading parameter for collective fluctuations is the excitation energy, whatever is its degree of thermalization. (orig.)

From stochastic phase-space evolution to brownian motion in collective space

International Nuclear Information System (INIS)

Benhassine, B.; Farine, M.; Hernandez, E.S.; Idier, D.; Remaud, B.; Sebille, F.

1994-01-01

Within the framework of stochastic transport equations in phase space, we study the dynamics of fluctuations on collective variables in homogeneous fermion systems. The transport coefficients are formally deduced in the relaxation-time approximation and a general method to compute dynamically the dispersions of collective observables is proposed as a set of coupled equations: respectively, the BUU/Landau-Vlasov equation for the average phase-space trajectories and the equations for the averages and dispersions of the observables. Independently, we derive the general covariance matrix of phase-space fluctuations and then by projection, the dispersion on collective variables at equilibrium. Detailed numerical applications of the formalism are given; they show that the dynamics of fluctuations can be extracted from noisy numerical simulations and that the leading parameter for collective fluctuations is the excitation energy, whatever is its degree of thermalization. (orig.)

Half-life measurement of 89Rb

International Nuclear Information System (INIS)

Guo Xiaoqing; Yuan Daqing; Xu Lijun; Chen Kesheng; Wu Yongle; Zheng Yanming; Yao Shunhe

2013-01-01

89 Rb is an important fission product used for monitoring possible release of fission products from fuel element. The half-life is one of important nuclear parameters. The half-life of 89 Rb was determined using reference source method with two sets of HPGe detectors by place-relay way. In reference source method, the ratio of net full- energy peak areas from the measure nuclide and the reference source was used to avoid the count correction caused by dead time and pileup. For the very short half-life of 89 Rb, the half-life iterative method was used in data analysis and the translation method was used in data unification. Finally, the measured half-life of 89 Rb is (14.41±0.04) min. (authors)

Broadband three-dimensional diamond-shaped invisible cloaks composed of tetrahedral homogeneous blocks

International Nuclear Information System (INIS)

Wang Xinhua; Qu Shaobo; Wu Xiang; Wang Jiafu; Ma Hua; Xu Zhuo

2010-01-01

By means of embedded optical transformation, three-dimensional diamond-shaped invisible cloaks composed of tetrahedral homogeneous blocks have been designed in this paper. The constitutive parameters of the invisible cloaks can be obtained based on the form invariance of Maxwell's equations in coordinate transformation. Numerical methods using the finite element method verified the diamond-shaped cloaks. The invisible properties of the designed cloaks are nearly perfect when the original line section is sufficiently short compared with its counterpart in the after-transformed space. The designed cloaks can operate in a wide bandwidth due to the line transformation in the coordinate transformation process.

Outer space structure and development

International Nuclear Information System (INIS)

Zeldovich, J.; Novikov, I.

1975-01-01

A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses. (J.K.)

Outer space structure and development

Energy Technology Data Exchange (ETDEWEB)

Zeldovich, J; Novikov, I

1975-10-01

A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses.

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1 +xSb solid solutions

Science.gov (United States)

Levin, Emily E.; Bocarsly, Joshua D.; Wyckoff, Kira E.; Pollock, Tresa M.; Seshadri, Ram

2017-12-01

Materials with a large magnetocaloric response are associated with a temperature change upon the application of a magnetic field and are of interest for applications in magnetic refrigeration and thermomagnetic power generation. The usual metric of this response is the gravimetric isothermal entropy change Δ SM . The use of a simple proxy for the Δ SM that is based on density functional theory (DFT) calculations of the magnetic electronic structure suggests that half-Heusler MnNiSb should be a better magnetocaloric than the corresponding Heusler compound MnNi2Sb . Guided by this observation, we present a study of MnNi1 +xSb (x =0 , 0.25, 0.5, 0.75, and 1.0) to evaluate relevant structural and magnetic properties. DFT stability calculations suggest that the addition of Ni takes place at a symmetrically distinct Ni site in the half-Heusler structure and support the observation using synchrotron x-ray diffraction of a homogeneous solid solution between the half-Heusler and Heusler end members. There is a maximum in the saturation magnetization at x =0.5 and the Curie temperature systematically decreases with increasing x . Δ SM for a maximum magnetic field change of Δ H =5 T monotonically decreases in magnitude from -2.93 J kg-1K-1 in the half-Heusler to -1.35 J kg-1K-1 in the Heusler compound. The concurrent broadening of the magnetic transition results in a maximum in the refrigerant capacity at x =0.75 . The Curie temperature of this system is highly tunable between 350 K and 750 K, making it ideal for low grade waste heat recovery via thermomagnetic power generation. The increase in Δ SM with decreasing x may be extendable to other MnNi2Z Heusler systems that are currently under investigation for use in magnetocaloric refrigeration applications.

Homogenization in powder compacts of UO2-PuO2

International Nuclear Information System (INIS)

Verma, R.

1979-01-01

The homogenization kinetics in mixed UO 2 -PuO 2 compacts have been studied by adopting a concentric core-shell model of diffusion. An equation relating the extent of homogenization expressed in terms of the fraction of UO 2 remaining undissolved and the time of annealing has been derived. From the equation, the periods required at different annealing temperatures to attain a specified level of homogenization have been calculated. These calculated homogenization times have been found to be in fair agreement with the experimentally observed homogenization times. The derived relationship has also been shown to satisfactorily predict homogenization in Cu-Ni powder compacts. (Auth.)

HUMAN SPACE FLIGHTS: FACTS AND DREAMS

OpenAIRE

Mariano Bizzarri; Enrico Saggese

2011-01-01

Manned space flight has been the great human and technological adventure of the past half-century. By putting people into places and situations unprecedented in history, it has stirred the imagination while expanding and redefining the human experience. However, space exploration obliges men to confront a hostile environment of cosmic radiation, microgravity, isolation and changes in the magnetic field. Any space traveler is therefore submitted to relevant health threats. In the twenty-first ...

Mechanical Design of the LHC Standard Half-Cell

Science.gov (United States)

Poncet, A.; Brunet, J. C.; Cruikshank, P.; Genet, M.; Parma, V.; Rohmig, P.; Saban, R.; Tavian, L.; Veness, R.; Vlogaert, J.; Williams, L. R.

1997-05-01

The LHC Conceptual Design Report issued on 20th October 1995 (CERN/AC/95-05 (LHC) - nicknamed "Yellow Book") introduced significant changes to some fundamental features of the LHC standard half-cell, composed of one quadrupole, 3 dipoles and a set of corrector magnets. A separate cryogenic distribution line was introduced, which was previously inside the main cryostat. The dipole length has been increased from 10 to 15 m and independent powering of the focusing and defocusing quadrupole magnets was chosen. Individual quench protection diodes were introduced in magnets interconnects and many auxiliary bus bars were added to feed in series the various families of correcting superconducting magnets. The various highly intricate basic systems such as: cryostats and cryogenics feeders, superconducting magnets and their electrical feeding and protection, vacuum beam screen and its cooling, support and alignment devices have been redesigned, taking into account the very tight space available. These space constraints are given by the necessity to have maximum integral bending field strength for maximum LHC energy, and the existing LHC tunnel. Finally, cryogenic and vacuum sectorisation have been introduced to reduce downtimes and facilitate commissioning.

Homogeneity and Entropy

Science.gov (United States)

Tignanelli, H. L.; Vazquez, R. A.; Mostaccio, C.; Gordillo, S.; Plastino, A.

1990-11-01

RESUMEN. Presentamos una metodologia de analisis de la homogeneidad a partir de la Teoria de la Informaci6n, aplicable a muestras de datos observacionales. ABSTRACT:Standard concepts that underlie Information Theory are employed in order design a methodology that enables one to analyze the homogeneity of a given data sample. Key : DATA ANALYSIS

7 CFR 51.1441 - Half-kernel.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Half-kernel. 51.1441 Section 51.1441 Agriculture... Standards for Grades of Shelled Pecans Definitions § 51.1441 Half-kernel. Half-kernel means one of the separated halves of an entire pecan kernel with not more than one-eighth of its original volume missing...

A direct proof of Sobolev embeddings for Triebel-Lizorkin spaces, including mixed norms and quasi-homogeneity

DEFF Research Database (Denmark)

Johnsen, Jon

The article deals with a simplified proof of the Sobolev embedding theorem for Triebel-Lizorkin spaces (that contain the $L_p$-Sobolev spaces $H^s_p$ as special cases). The method extends to a proof of the corresponding fact for general Triebel–Lizorkin spaces based on mixed $L_p$-norms...

Homogenization models for thin rigid structured surfaces and films.

Science.gov (United States)

Marigo, Jean-Jacques; Maurel, Agnès

2016-07-01

A homogenization method for thin microstructured surfaces and films is presented. In both cases, sound hard materials are considered, associated with Neumann boundary conditions and the wave equation in the time domain is examined. For a structured surface, a boundary condition is obtained on an equivalent flat wall, which links the acoustic velocity to its normal and tangential derivatives (of the Myers type). For a structured film, jump conditions are obtained for the acoustic pressure and the normal velocity across an equivalent interface (of the Ventcels type). This interface homogenization is based on a matched asymptotic expansion technique, and differs slightly from the classical homogenization, which is known to fail for small structuration thicknesses. In order to get insight into what causes this failure, a two-step homogenization is proposed, mixing classical homogenization and matched asymptotic expansion. Results of the two homogenizations are analyzed in light of the associated elementary problems, which correspond to problems of fluid mechanics, namely, potential flows around rigid obstacles.

PREFACE: Half Metallic Ferromagnets

Science.gov (United States)

Dowben, Peter

2007-08-01

Since its introduction by de Groot and colleagues in the early 1980s [1], the concept of half metallic ferromagnetism has attracted great interest. Idealized, half-metals have only one spin channel for conduction: the spin-polarized band structure exhibits metallic behavior for one spin channel, while the other spin band structure exhibits a gap at the Fermi level. Due to the gap for one spin direction, the density of states at the Fermi level has, theoretically, 100 & spin polarization. This gap in the density of states in one spin at the Fermi level, for example ↓ so N↓ (EF) = 0, also causes the resistance of that channel to go to infinity. At zero or low temperatures, the nonquasiparticle density of states (electron correlation effects), magnons and spin disorder reduce the polarization from the idealized 100 & polarization. At higher temperatures magnon-phonon coupling and irreversible compositional changes affect polarization further. Strategies for assessing and reducing the effects of finite temperatures on the polarization are now gaining attention. The controversies surrounding the polarization stability of half metallic ferromagnets are not, however, limited to the consideration of finite temperature effects alone. While many novel half metallic materials have been predicted, materials fabrication can be challenging. Defects, surface and interface segregation, and structural stability can lead to profound decreases in polarization, but can also suppress long period magnons. There is a 'delicate balance of energies required to obtain half metallic behaviour: to avoid spin flip scattering, tiny adjustments in atomic positions might occur so that a gap opens up in the other spin channel' [2]. When considering 'spintronics' devices, a common alibi for the study of half metallic systems, surfaces and interfaces become important. Free enthalpy differences between the surface and the bulk will lead to spin minority surface and interface states, as well as

Sewage sludge disintegration by high-pressure homogenization: a sludge disintegration model.

Science.gov (United States)

Zhang, Yuxuan; Zhang, Panyue; Ma, Boqiang; Wu, Hao; Zhang, Sheng; Xu, Xin

2012-01-01

High-pressure homogenization (HPH) technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree (DD(COD)), protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid (TS) content. The maximum DD(COD) of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DD(COD) = kNaPb was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure (P) was more significant than that of homogenization cycle number (N). The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.

Non-periodic homogenization of 3-D elastic media for the seismic wave equation

Science.gov (United States)

Cupillard, Paul; Capdeville, Yann

2018-05-01

Because seismic waves have a limited frequency spectrum, the velocity structure of the Earth that can be extracted from seismic records has a limited resolution. As a consequence, one obtains smooth images from waveform inversion, although the Earth holds discontinuities and small scales of various natures. Within the last decade, the non-periodic homogenization method shed light on how seismic waves interact with small geological heterogeneities and `see' upscaled properties. This theory enables us to compute long-wave equivalent density and elastic coefficients of any media, with no constraint on the size, the shape and the contrast of the heterogeneities. In particular, the homogenization leads to the apparent, structure-induced anisotropy. In this paper, we implement this method in 3-D and show 3-D tests for the very first time. The non-periodic homogenization relies on an asymptotic expansion of the displacement and the stress involved in the elastic wave equation. Limiting ourselves to the order 0, we show that the practical computation of an upscaled elastic tensor basically requires (i) to solve an elastostatic problem and (ii) to low-pass filter the strain and the stress associated with the obtained solution. The elastostatic problem consists in finding the displacements due to local unit strains acting in all directions within the medium to upscale. This is solved using a parallel, highly optimized finite-element code. As for the filtering, we rely on the finite-element quadrature to perform the convolution in the space domain. We end up with an efficient numerical tool that we apply on various 3-D models to test the accuracy and the benefit of the homogenization. In the case of a finely layered model, our method agrees with results derived from Backus. In a more challenging model composed by a million of small cubes, waveforms computed in the homogenized medium fit reference waveforms very well. Both direct phases and complex diffracted waves are

Lasers in space.

CSIR Research Space (South Africa)

Michaelis, MM

2008-04-01

Full Text Available cube, laser beam reflectors, placed on the Moon half a century ago. These early achievements will soon be followed by a plethora of experiments involving lasers in low earth orbit (LEO) or at Lagrange points. And not much later, laser communications... will stretch out as far as Mars and beyond. One important low Earth orbit (LEO) application is the removal of space debris by Earth based or LEO relayed lasers as promoted by Phipps et al.3. Another is military communication. The prominent L1 laser space...

Title: a simple method to evaluate linac beam homogeneity

International Nuclear Information System (INIS)

Monti, A.F.; Ostinelli, A.; Gelosa, S.; Frigerio, M.

1995-01-01

Quality Control (QC) tests in Radiotherapy represent a basic requirement to asses treatment units performance and treatment quality. Since they are generally time consuming, it is worth while to introduce procedures and methods which can be carried on more easily and quickly. Since 1994 in the Radiotherapy Department of S. Anna Hospital, it had been employed a commercially available solid phantom (PRECITRON) with a 10 diodes array, to investigate beam homogeneity (symmetry and flatness). In particular, global symmetry percentage indexes were defined which consider pairs of corresponding points along each axis (x and y) and compare the readings of the respective diodes, following the formula: (I gs =((X d + X -d ) - (Y d + Y -d )((X d + X -d ) + (Y d + Y -d )*200 where X d and X -d are points 8 or 10 cm equally spaced from the beam centre along x axis and the same for Y d and Y -d along y axis. Even if non supporting international protocols requirements as a whole, this parameter gives an important information about beam homogeneity, when only few points of measure are available in a plane, and it can be daily determined, thus fulfilling the aim of lightning immediately each situation capable to compromise treatment accuracy and effectiveness. In this poster we report the results concerning this parameter for a linear accelerator (Varian Clinac 1800), since September 1994 to September 1995

Microstructure and Mechanical Properties of the As-Cast and As-Homogenized Mg-Zn-Sn-Mn-Ca Alloy Fabricated by Semicontinuous Casting

Science.gov (United States)

Lu, Xing; Zhao, Guoqun; Zhou, Jixue; Zhang, Cunsheng; Yu, Junquan

2018-01-01

In this paper, a new type of low-cost Mg-3.36Zn-1.06Sn-0.33Mn-0.27Ca (wt %) alloy ingot with a diameter of 130 mm and a length of 4800 mm was fabricated by semicontinuous casting. The microstructure and mechanical properties at different areas of the ingot were investigated. The microstructure and mechanical properties of the alloy under different one-step and two-step homogenization conditions were studied. For the as-cast alloy, the average grain size and the second phase size decrease from the center to the surface of the ingot, while the area fraction of the second phase increases gradually. At one-half of the radius of the ingot, the alloy presents the optimum comprehensive mechanical properties along the axial direction, which is attributed to the combined effect of relatively small grain size, low second-phase fraction, and uniform microstructure. For the as-homogenized alloy, the optimum two-step homogenization process parameters were determined as 340 °C × 10 h + 520 °C × 16 h. After the optimum homogenization, the proper size and morphology of CaMgSn phase are conducive to improve the microstructure uniformity and the mechanical properties of the alloy. Besides, the yield strength of the alloy is reduced by 20.7% and the elongation is increased by 56.3%, which is more favorable for the subsequent hot deformation processing. PMID:29710818

Microstructure and Mechanical Properties of the As-Cast and As-Homogenized Mg-Zn-Sn-Mn-Ca Alloy Fabricated by Semicontinuous Casting.

Science.gov (United States)

Lu, Xing; Zhao, Guoqun; Zhou, Jixue; Zhang, Cunsheng; Yu, Junquan

2018-04-29

In this paper, a new type of low-cost Mg-3.36Zn-1.06Sn-0.33Mn-0.27Ca (wt %) alloy ingot with a diameter of 130 mm and a length of 4800 mm was fabricated by semicontinuous casting. The microstructure and mechanical properties at different areas of the ingot were investigated. The microstructure and mechanical properties of the alloy under different one-step and two-step homogenization conditions were studied. For the as-cast alloy, the average grain size and the second phase size decrease from the center to the surface of the ingot, while the area fraction of the second phase increases gradually. At one-half of the radius of the ingot, the alloy presents the optimum comprehensive mechanical properties along the axial direction, which is attributed to the combined effect of relatively small grain size, low second-phase fraction, and uniform microstructure. For the as-homogenized alloy, the optimum two-step homogenization process parameters were determined as 340 °C × 10 h + 520 °C × 16 h. After the optimum homogenization, the proper size and morphology of CaMgSn phase are conducive to improve the microstructure uniformity and the mechanical properties of the alloy. Besides, the yield strength of the alloy is reduced by 20.7% and the elongation is increased by 56.3%, which is more favorable for the subsequent hot deformation processing.

A non-asymptotic homogenization theory for periodic electromagnetic structures.

Science.gov (United States)

Tsukerman, Igor; Markel, Vadim A

2014-08-08

Homogenization of electromagnetic periodic composites is treated as a two-scale problem and solved by approximating the fields on both scales with eigenmodes that satisfy Maxwell's equations and boundary conditions as accurately as possible. Built into this homogenization methodology is an error indicator whose value characterizes the accuracy of homogenization. The proposed theory allows one to define not only bulk, but also position-dependent material parameters (e.g. in proximity to a physical boundary) and to quantify the trade-off between the accuracy of homogenization and its range of applicability to various illumination conditions.

Homogenization of Large-Scale Movement Models in Ecology

Science.gov (United States)

Garlick, M.J.; Powell, J.A.; Hooten, M.B.; McFarlane, L.R.

2011-01-01

A difficulty in using diffusion models to predict large scale animal population dispersal is that individuals move differently based on local information (as opposed to gradients) in differing habitat types. This can be accommodated by using ecological diffusion. However, real environments are often spatially complex, limiting application of a direct approach. Homogenization for partial differential equations has long been applied to Fickian diffusion (in which average individual movement is organized along gradients of habitat and population density). We derive a homogenization procedure for ecological diffusion and apply it to a simple model for chronic wasting disease in mule deer. Homogenization allows us to determine the impact of small scale (10-100 m) habitat variability on large scale (10-100 km) movement. The procedure generates asymptotic equations for solutions on the large scale with parameters defined by small-scale variation. The simplicity of this homogenization procedure is striking when compared to the multi-dimensional homogenization procedure for Fickian diffusion,and the method will be equally straightforward for more complex models. ?? 2010 Society for Mathematical Biology.

Linear embeddings of finite-dimensional subsets of Banach spaces into Euclidean spaces

International Nuclear Information System (INIS)

Robinson, James C

2009-01-01

This paper treats the embedding of finite-dimensional subsets of a Banach space B into finite-dimensional Euclidean spaces. When the Hausdorff dimension of X − X is finite, d H (X − X) k are injective on X. The proof motivates the definition of the 'dual thickness exponent', which is the key to proving that a prevalent set of such linear maps have Hölder continuous inverse when the box-counting dimension of X is finite and k > 2d B (X). A related argument shows that if the Assouad dimension of X − X is finite and k > d A (X − X), a prevalent set of such maps are bi-Lipschitz with logarithmic corrections. This provides a new result for compact homogeneous metric spaces via the Kuratowksi embedding of (X, d) into L ∞ (X)

Layer potentials and boundary-value problems for second order elliptic operators with data in Besov spaces

CERN Document Server

Barton, Ariel

2016-01-01

This monograph presents a comprehensive treatment of second order divergence form elliptic operators with bounded measurable t-independent coefficients in spaces of fractional smoothness, in Besov and weighted L^p classes. The authors establish: (1) Mapping properties for the double and single layer potentials, as well as the Newton potential; (2) Extrapolation-type solvability results: the fact that solvability of the Dirichlet or Neumann boundary value problem at any given L^p space automatically assures their solvability in an extended range of Besov spaces; (3) Well-posedness for the non-homogeneous boundary value problems. In particular, the authors prove well-posedness of the non-homogeneous Dirichlet problem with data in Besov spaces for operators with real, not necessarily symmetric, coefficients.

Simulation of ferric ions transfer in dosemeter Fricke-Xylenol-Gel in means no homogeneous

International Nuclear Information System (INIS)

Milani, Caio J.; Bevilacqua, Joyce da Silva; Cavinato, Christianne C.; Rodrigues Junior, Orlando; Campos, Leticia L.

2013-01-01

Dosimetry in three dimensions using Fricke-Xilenol-Gel dosimeters (FXG) allows the confirmation and a better understanding of a treatment by Radiotherapy. The technique involves the assessment of the irradiated volumes by magnetic resonance imaging (MRI) or optical-CT. On both cases, the time elapsed between the irradiation and the measurement is an important factor in the quality of results. The quality of the images can be compromised by the mobility of the ferric ions (Fe 3+ ), formed during the the interaction of the radiation with the matter, increasing the uncertainty in the determination of the isodoses in the volume. In this work, the phenomenon of the diffusion of the ferric ions formed by an irradiated region is simulated in a bidimensional domain. The dynamic of the Fe 3+ in Fricke-Gel is modeled by a parabolic partial differential equation and solved by the ADI-Peaceman-Rachford algorithm. Stability and consistency of the method guarantee the convergence of the numerical solution for a pre-defined error magnitude, based on choices for the discretization values of time and space. Homogeneous and non-homogeneous cases are presented considering an irradiated region and a physical barrier that prevents the movement of the ions, on the non-homogeneous case. Graphical visualizations of the phenomenon are presented for better understanding of the process. (author)

Neutron diffraction study of cubic titanium carbohydride at the homogeneity lower limit

International Nuclear Information System (INIS)

Khidirov, I.; Mirzaev, B.B.; Mukhtarova, N.N.

2004-01-01

Cubic carbohydride TiC 0.47H0.22 was prepared by means of quenching from 1200 deg.C followed by the heat treatment using special regime for preventing the hydrogen yield out the lattice. It is shown that at the lower limit of homogeneity range of the cubic carbohydride, hydrogen atoms occupy the tetrahedral interstices 8(c) of the disordered cubic structure with space group of Fm3m. It is found that carbon and hydrogen atoms are partially ordered by annealing at 900-700 deg.C. The ordered structure is face-centred cubic lattice with the parameter a ≅2a 0 , where a 0 is the lattice parameter in disordered structure. The crystal structure of the disordered phase is described within the framework of space group Fd3m, where the carbon atoms occupy mainly (70%) octahedral interstices 16(c) and another ones of carbon and all hydrogen atoms occupy the octahedral interstices 16(d). (author)

Persymmetric Adaptive Detectors of Subspace Signals in Homogeneous and Partially Homogeneous Clutter

Directory of Open Access Journals (Sweden)

Ding Hao

2015-08-01

Full Text Available In the field of adaptive radar detection, an effective strategy to improve the detection performance is to exploit the structural information of the covariance matrix, especially in the case of insufficient reference cells. Thus, in this study, the problem of detecting multidimensional subspace signals is discussed by considering the persymmetric structure of the clutter covariance matrix, which implies that the covariance matrix is persymmetric about its cross diagonal. Persymmetric adaptive detectors are derived on the basis of the one-step principle as well as the two-step Generalized Likelihood Ratio Test (GLRT in homogeneous and partially homogeneous clutter. The proposed detectors consider the structural information of the covariance matrix at the design stage. Simulation results suggest performance improvement compared with existing detectors when reference cells are insufficient. Moreover, the detection performance is assessed with respect to the effects of the covariance matrix, signal subspace dimension, and mismatched performance of signal subspace as well as signal fluctuations.

Space, Art and Transcendence

Directory of Open Access Journals (Sweden)

Ricardo Pinilla Burgos

2017-09-01

Full Text Available In the light of Heidegger’s analysis of space and art, and its link with a milestone for modern sculpture such as Eduardo Chillida, space is presented, together with time, as a fundamental element of art and especially of sculpture and architecture. Space is not a homogeneous neutral background, but an original phenomenon that compromises from the beginning the creation and the peculiar kind of transcendence to which every work of art invites us. Every work submerges us on one side in a feverish, sensitive and bodily immanence, in the mystery of the sensitive (aesthetic that we are, but aswell it takes us beyond or nearer than the conventional meanings and relations and our situation. From here, we will consider whether and how we can put the aesthetic experience of space in relation to the transcendence of which religion commonly speaks, illuminated in turn from the study of the sacred of Mircea Eliade.

Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

Science.gov (United States)

Singh, Abhishek Kumar; Das, Amrita; Parween, Zeenat; Chattopadhyay, Amares

2015-10-01

The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

Layout optimization using the homogenization method

Science.gov (United States)

Suzuki, Katsuyuki; Kikuchi, Noboru

1993-01-01

A generalized layout problem involving sizing, shape, and topology optimization is solved by using the homogenization method for three-dimensional linearly elastic shell structures in order to seek a possibility of establishment of an integrated design system of automotive car bodies, as an extension of the previous work by Bendsoe and Kikuchi. A formulation of a three-dimensional homogenized shell, a solution algorithm, and several examples of computing the optimum layout are presented in this first part of the two articles.

Peripheral nerve magnetic stimulation: influence of tissue non-homogeneity

Directory of Open Access Journals (Sweden)

Papazov Sava P

2003-12-01

Full Text Available Abstract Background Peripheral nerves are situated in a highly non-homogeneous environment, including muscles, bones, blood vessels, etc. Time-varying magnetic field stimulation of the median and ulnar nerves in the carpal region is studied, with special consideration of the influence of non-homogeneities. Methods A detailed three-dimensional finite element model (FEM of the anatomy of the wrist region was built to assess the induced currents distribution by external magnetic stimulation. The electromagnetic field distribution in the non-homogeneous domain was defined as an internal Dirichlet problem using the finite element method. The boundary conditions were obtained by analysis of the vector potential field excited by external current-driven coils. Results The results include evaluation and graphical representation of the induced current field distribution at various stimulation coil positions. Comparative study for the real non-homogeneous structure with anisotropic conductivities of the tissues and a mock homogeneous media is also presented. The possibility of achieving selective stimulation of either of the two nerves is assessed. Conclusion The model developed could be useful in theoretical prediction of the current distribution in the nerves during diagnostic stimulation and therapeutic procedures involving electromagnetic excitation. The errors in applying homogeneous domain modeling rather than real non-homogeneous biological structures are demonstrated. The practical implications of the applied approach are valid for any arbitrary weakly conductive medium.

Spatial homogenization method based on the inverse problem

International Nuclear Information System (INIS)

Tóta, Ádám; Makai, Mihály

2015-01-01

Highlights: • We derive a spatial homogenization method in slab and cylindrical geometries. • The fluxes and the currents on the boundary are preserved. • The reaction rates and the integral of the fluxes are preserved. • We present verification computations utilizing two- and four-energy groups. - Abstract: We present a method for deriving homogeneous multi-group cross sections to replace a heterogeneous region’s multi-group cross sections; providing that the fluxes, the currents on the external boundary, the reaction rates and the integral of the fluxes are preserved. We consider one-dimensional geometries: a symmetric slab and a homogeneous cylinder. Assuming that the boundary fluxes are given, two response matrices (RMs) can be defined concerning the current and the flux integral. The first one derives the boundary currents from the boundary fluxes, while the second one derives the flux integrals from the boundary fluxes. Further RMs can be defined that connects reaction rates to the boundary fluxes. Assuming that these matrices are known, we present formulae that reconstruct the multi-group diffusion cross-section matrix, the diffusion coefficients and the reaction cross sections in case of one-dimensional (1D) homogeneous regions. We apply these formulae to 1D heterogeneous regions and thus obtain a homogenization method. This method produces such an equivalent homogeneous material, that the fluxes and the currents on the external boundary, the reaction rates and the integral of the fluxes are preserved for any boundary fluxes. We carry out the exact derivations in 1D slab and cylindrical geometries. Verification computations for the presented homogenization method were performed using two- and four-group material cross sections, both in a slab and in a cylindrical geometry

Homogeneous bilateral block shifts

Indian Academy of Sciences (India)

Douglas class were classified in [3]; they are unilateral block shifts of arbitrary block size (i.e. dim H(n) can be anything). However, no examples of irreducible homogeneous bilateral block shifts of block size larger than 1 were known until now.

Osteoarthritic Cartilage is more Homogeneous than Healthy Cartilage – Identification of a Superior ROI Co-localised with a Major Risk Factor for Osteoarthritis

DEFF Research Database (Denmark)

Qazi, Arish Asif; Dam, Erik B.; Nielsen, Mads

2007-01-01

Rationale and Objectives Cartilage loss as determined by magnetic resonance imaging (MRI) or joint space narrowing as determined by x-ray is the result of cartilage erosion. However, metabolic processes within the cartilage that later result in cartilage loss may be a more sensitive assessment...... method for early changes. Recently, it was shown that cartilage homogeneity visualized by MRI representing the biochemical changes undergoing in the cartilage is a potential marker for early detection of knee osteoarthritis (OA) and is also able to significantly separate groups of healthy subjects from...... those with OA. The purpose of this study was twofold. First, we wished to evaluate whether the results on cartilage homogeneity from the previous study can be reproduced using an independent population. Second, based on the homogeneity framework, we present an automatic technique that partitions...

Areva. 2005 half year report

International Nuclear Information System (INIS)

2005-01-01

With manufacturing facilities in over 40 countries and a sales network in over 100, AREVA offers customers technological solutions for nuclear power generation and electricity transmission and distribution. The group also provides interconnect systems to the telecommunications, computer and automotive markets. This half-year report of Areva group presents the key financial data of the group for the first half of 2005: 1 - Highlights of the period; 2 - Transition to the International Financial Reporting Standards: Group's application of IFRS, Impact of IAS 32 and 39 adoption on the Group's financial statements; 3 - Key data: summary data, summary data by business Division, backlog, income statement, review by business Division, cash flow statement, balance sheet items; 4 - events subsequent to the half-year-end; 5 - consolidated financial statements: statutory Auditors' report on the 2005 half-year financial statements - period from January 1 to June 30, 2005, consolidated income statement, consolidated balance sheet, consolidated cash flow statement, change in consolidated shareholders' equity, data by business Division and region, notes to the consolidated financial statements; 6 - Outlook

Surface wave propagation in a double liquid layer over a liquid ...

Indian Academy of Sciences (India)

The frequency equation is derived for surface waves in a liquidsaturated porous half-space supporting a double layer, that of inhomogeneous and homogeneous liquids. Asymptotic approximations of Bessel functions are used for long and short wavelength cases. Certain other problems are discussed as special cases.