Sample records for harmonic analysis physics

  1. Harmonic Analysis

    Microsoft Academic Search

    Vladimir I Clue; William Kelleher; Anatoly Levin

    2005-01-01

    This paper describes a method of calculating the transforms, currently\\u000aobtained via Fourier and reverse Fourier transforms. The method allows\\u000acalculating efficiently the transforms of a signal having an arbitrary\\u000adimension of the digital representation by reducing the transform to a\\u000avector-to-circulant matrix multiplying. There is a connection between harmonic\\u000aequations in rectangular and polar coordinate systems. The connection\\u000aestablished

  2. HARMONIC ANALYSIS TERENCE TAO

    E-print Network

    Tao, Terence

    HARMONIC ANALYSIS TERENCE TAO Analysis in general tends to revolve around the study of general functions as input, and return some other function as output). Harmonic analysis1 focuses in particular Strictly speaking, this sentence describes the field of real-variable harmonic analysis. There is another

  3. PHYSICS REPORTS (Review Section of Physics Letters) 196. Nos. 1 & 2 (1990) 1--134. North-Holland HARMONIC ANALYSIS AND PROPAGATORS ON

    E-print Network

    Ceragioli, Francesca

    1990-01-01

    PHYSICS REPORTS (Review Section of Physics Letters) 196. Nos. 1 & 2 (1990) 1--134. North for this issue PHYSICS REPORTS (Review Section of Physics Letters) 196, Nos. 1 & 2(1990)1--134. Copies-Holland HARMONIC ANALYSIS AND PROPAGATORS ON HOMOGENEOUS SPACES Roberto CAMPORESI Department of Physics

  4. Physics 116 Simple Harmonic Motion

    E-print Network

    Glashausser, Charles

    Physics 116 Simple Harmonic Motion Any Simple Harmonic Oscillator (SHO) has the following features Harmonic Motion (SHM). If the system is a SHO, then the following is true: MASS-SPRING system of the motion. Because of (3) above, we characterize SH oscillators based on their oscillation frequencies

  5. Hippocampal Surface Analysis using Spherical Harmonic Functions

    E-print Network

    Wang, Yalin

    Hippocampal Surface Analysis using Spherical Harmonic Functions Applied to Surface Conformal Laplacian is Spherical harmonic analysis applied to conforaml mapping Let be a conformal homeomorphism of Neurology, UCLA School of Medicine, Los Angeles, CA, USA. The spherical harmonic descriptors should

  6. Physics 321 Simple and Damped Harmonic Oscillators

    E-print Network

    Hart, Gus

    Physics 321 Hour 11 Simple and Damped Harmonic Oscillators Mass on a Massless Spring 1) Find U) x y z Example Lissajous.nb Damped Oscillator The equation: A little rearranging: 0 A trial Driven Harmonic Oscillators #12;Driven Oscillator The equation: 0 Let The oscillator wants

  7. Applied and Numerical Harmonic Analysis Series Editor

    E-print Network

    O'Brien, James F.

    #12;Applied and Numerical Harmonic Analysis Series Editor John J. Benedetto University of Maryland and Numerical Harmonic Analysis (ANHA) book series aims to provide the engineering, mathematical, and scientific communities with significant develop- ments in harmonic analysis, ranging from abstract harmonic analysis

  8. Harmonic Analysis of Neural Networks

    Microsoft Academic Search

    Emmanuel J. Candès

    1999-01-01

    It is known that superpositions of ridge functions (single hidden-layer feedforward neural networks) may give good approximations to certain kinds of multivariate functions. It remains unclear, however, how to effectively obtain such approximations. In this paper, we use ideas from harmonic analysis to attack this question. We introduce a special admissibility condition for neural activation functions. The new condition is

  9. The harmonic oscillator and nuclear physics

    NASA Technical Reports Server (NTRS)

    Rowe, D. J.

    1993-01-01

    The three-dimensional harmonic oscillator plays a central role in nuclear physics. It provides the underlying structure of the independent-particle shell model and gives rise to the dynamical group structures on which models of nuclear collective motion are based. It is shown that the three-dimensional harmonic oscillator features a rich variety of coherent states, including vibrations of the monopole, dipole, and quadrupole types, and rotations of the rigid flow, vortex flow, and irrotational flow types. Nuclear collective states exhibit all of these flows. It is also shown that the coherent state representations, which have their origins in applications to the dynamical groups of the simple harmonic oscillator, can be extended to vector coherent state representations with a much wider range of applicability. As a result, coherent state theory and vector coherent state theory become powerful tools in the application of algebraic methods in physics.

  10. Harmonic Analysis of Neural Networks

    Microsoft Academic Search

    Emmanuel J. Candès

    1998-01-01

    It is known that superpositions of ridge functions (single hidden-layer feedforward neuralnetworks) may give good approximations to certain kinds of multivariate functions. It remainsunclear, however, how to eectively obtain such approximations.In this paper, we use ideas from harmonic analysis to attack this question. We introduce aspecial admissibility condition for neural activation functions. The new condition is not satis-ed by the

  11. Bayesian harmonic models for musical signal analysis

    E-print Network

    Godsill, Simon

    Bayesian harmonic models for musical signal analysis Simon Godsill and Manuel Davy June 2, 2002 harmonic models 4. Computations 5. Results 6. Discussion 5 #12;Overview 1. Music modelling issues 2. Other work 3. Bayesian harmonic models 4. Computations 5. Results 6. Discussion 5 #12;Overview 1. Music

  12. Harmonic oscillator: an analysis via Fourier series

    E-print Network

    A. S. de Castro

    2013-09-30

    The Fourier series method is used to solve the homogeneous equation governing the motion of the harmonic oscillator. It is shown that the general solution to the problem can be found in a surprisingly simple way for the case of the simple harmonic oscillator. It is also shown that the damped harmonic oscillator is susceptible to the analysis.

  13. Quantum harmonic oscillator state synthesis and analysis

    E-print Network

    Quantum harmonic oscillator state synthesis and analysis W. M. Itano, C. Monroe, D. M. Meekhof, D to the ground (n = 0) quantum harmonic oscillator state with greater than 90% probability. From this starting single, trapped, 9 Be+ ions in various quantum harmonic oscillator states and performed measurements

  14. A TECHNICAL SURVEY OF HARMONIC ANALYSIS TERENCE TAO

    E-print Network

    Tao, Terence

    A TECHNICAL SURVEY OF HARMONIC ANALYSIS TERENCE TAO-variable harmonic analysis, and some of the techni* *ques being developed. Note: references are completely broadly speaking, harmonic analysis is centered around the analysis (in pa* *r- ticular, quantitative

  15. Spherical harmonic analysis of wavefields using multiple circular sensor arrays

    E-print Network

    Abhayapala, Thushara D.

    Spherical harmonic analysis of wavefields using multiple circular sensor arrays Thushara D 1 Spherical harmonic analysis of wavefields using multiple circular sensor arrays I. INTRODUCTION Spherical harmonic analysis of three dimensional wavefields is a useful tool in designing signal processing

  16. Open Positions at the Numerical Harmonic Analysis Group

    E-print Network

    Feichtinger, Hans Georg

    Open Positions at the Numerical Harmonic Analysis Group The Numerical Harmonic Analysis Group (Nu¨ochenig. The successful candidate will be part of the Numerical Harmonic Analysis group. NuHAG is an international abstract harmonic analysis to concrete computational problems in time-frequency analysis and sampling

  17. Harmonic analysis in rigidity theory R. J. Spatzier

    E-print Network

    Spatzier, Ralf

    Harmonic analysis in rigidity theory R. J. Spatzier Contents 1 Introduction 2 2 A Synopsis for short. Harmonic analysis has most often come into play in the guise of the representation theory. There are certainly other ways in which harmonic analysis enters the subject. For example, harmonic functions

  18. Venus topography - A harmonic analysis

    NASA Technical Reports Server (NTRS)

    Bills, B. G.; Kobrick, M.

    1985-01-01

    A model of Venusian global topography has been obtained by fitting an eighteenth-degree harmonic series to Pioneer Venus orbiter radar altimeter data. The mean radius is (6051.45 + or - 0.04) km. The corresponding mean density is (5244.8 + or 0.5) kg/cu m. The center of figure is displaced from the center of mass by (0.339 + or - 0.088) km towards (6.6 + or 10.1) deg N, (148. 8 + or - 7.7) deg. The figure of Venus is distinctly triaxial, but the orientation and magnitudes of the principal topographic axes correlate rather poorly with the gravitational principal axes. However, the higher-degree harmonics of topography and gravity are significantly correlated. The topographic variance spectrum of Venus is very similar in form to those of the moon, Mars, and especially earth. It is suggested that this spectral similarity simply reflects a statistical balance between constructional and degradational geomorphic proceses. Venus and earth are particularly similar (and differ from the moon and Mars) in that the larger bodies both exhibit a significant low degree deficit (relative to the extrapolated trend of the higher harmonics).

  19. Abstract Harmonic Analysis on Spacetime

    E-print Network

    Kahar El-Hussein

    2014-04-06

    In this paper, we consider the Poincare group (space time). In mathematics, the Poincar\\'e group of spacetime, named after Henri Poincar\\'e, is the group of isometries of Minkowski spacetime, introduced by Hermann Minkowski. It is a non-abelian Lie group with ten generators. Spacetime, in physical science, single concept that recognizes the union of space and time, posited by Albert Einstein in the theories of relativity. One of the interesting problems for Mathematicians and Physicists is. Can we do the Fourier analysis on space time. The purpose of this paper is to define the Fourier transform the Poincar\\'e group, and then we establish the Plancherel theorem for spacetime

  20. D. Gurarie's publications HARMONIC ANALYSIS, LIE GROUPS AND REPRESENTATIONS

    E-print Network

    Gurarie, David

    D. Gurarie's publications HARMONIC ANALYSIS, LIE GROUPS AND REPRESENTATIONS (1973-1984) 1. Gurarii operator. Functional Analysis and Its Applications. 1974;8(4):340-341. 3. Gurarie D. Harmonic analysis based on crossed product algebras and motion groups. Harmonic Analysis Iraklion 1978. 1980:59-75. 4

  1. A TECHNICAL SURVEY OF HARMONIC ANALYSIS TERENCE TAO

    E-print Network

    Tao, Terence

    A TECHNICAL SURVEY OF HARMONIC ANALYSIS TERENCE TAO Abstract. A rather technical description of some of the active areas of re- search in modern real-variable harmonic analysis, and some overview Very broadly speaking, harmonic analysis is centered around the analysis (in par- ticular

  2. Physics of tissue harmonic imaging by ultrasound

    NASA Astrophysics Data System (ADS)

    Jing, Yuan

    Tissue Harmonic Imaging (THI) is an imaging modality that is currently deployed on diagnostic ultrasound scanners. In THI the amplitude of the ultrasonic pulse that is used to probe the tissue is large enough that the pulse undergoes nonlinear distortion as it propagates into the tissue. One result of the distortion is that as the pulse propagates energy is shifted from the fundamental frequency of the source pulse into its higher harmonics. These harmonics will scatter off objects in the tissue and images formed from the scattered higher harmonics are considered to have superior quality to the images formed from the fundamental frequency. Processes that have been suggested as possibly responsible for the improved imaging in THI include: (1) reduced sensitivity to reverberation, (2) reduced sensitivity to aberration, and (3) reduction in side lobes. By using a combination of controlled experiments and numerical simulations, these three reasons have been investigated. A single element transducer and a clinical ultrasound scanner with a phased array transducer were used to image a commercial tissue-mimicking phantom with calibrated targets. The higher image quality achieved with THI was quantified in terms of spatial resolution and "clutter" signals. A three-dimensional model of the forward propagation of nonlinear sound beams in media with arbitrary spatial properties (a generalized KZK equation) was developed. A time-domain code for solving the KZK equation was validated with measurements of the acoustic field generated by the single element transducer and the phased array transducer. The code was used to investigate the impact of aberration using tissue-like media with three-dimensional variations in all acoustic properties. The three-dimensional maps of tissue properties were derived from the datasets available through the Visible Female project. The experiments and simulations demonstrated that second harmonic imaging (1) suffers less clutter associated with reverberation; (2) is not immune to aberration effects and (3) suffers less clutter due to reduced side-lobe levels. The results indicate that side lobe suppression is the most significant reason for the improvement of second harmonic imaging.

  3. Analysis of Harmonic and Inter-Harmonic Based on Hilbert-Huang Transform

    Microsoft Academic Search

    Jianming Yu; Liang Yang

    2009-01-01

    To analyze harmonic and inter-harmonic accurately is significant to the stability of power system. The Hilbert-Huang transform (HHT) is adopted to analyze harmonic and interharmonic in order to overcome the shortcoming of FFT method and wavelet analysis method. The power quality signals are decomposed by empirical mode decomposition (EMD) method, and then a series of intrinsic mode function (IMF) are

  4. Venus gravity - A harmonic analysis

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G.; Jones, Robert L.; Kiefer, Walter S.

    1987-01-01

    An improved model of Venusian global gravity has been obtained by fitting an eighteenth-degree and eighteenth-order spherical harmonic series to 78 orbital arcs of high altitude (950-1350 km at periapsis) tracking data and 351 orbital arcs of lower-altitude (150-200 km at periapsis) data from the Pioneer Venus Orbiter (PVO). Compared to a recently published tenth-degree model of Mottinger et al. (1985), which is based on the 78 high-altitude arcs only, the current model provides a significant improvement in resolution and fidelity. As a measure of this improvement, it is noted that for the low-altitude arcs alone, the variance of the residuals for the present model is reduced to 19 percent of the data variance, compared to 51 percent for the tenth-degree model. Venus differs significantly from the earth in that it exhibits a significant correlation between long-wavelength topography and gravity. The gravity/topography spectral admittances are inconsistent with either Airy or Pratt isostasy, but are consistent with dynamic support by mantle convection.

  5. Analysis of Voiced Speech using Harmonic Models Yannis Stylianou

    E-print Network

    Greenberg, Albert

    Analysis of Voiced Speech using Harmonic Models Yannis Stylianou AT&T Labs Research, 180 Park Ave. This paper focuses on the harmonic analysis of speech. Three models are presented and compared. The rst model will refer to all the other regions as unvoiced". This paper focuses on the harmonic analysis of voiced

  6. Elements of Postmodern Harmonic Analysis Hans G. Feichtinger

    E-print Network

    Feichtinger, Hans Georg

    Elements of Postmodern Harmonic Analysis Hans G. Feichtinger hans.feichtinger@univie.ac.at October 1, 2013 Abstract Harmonic Analysis (HA) has the Fourier transform, convolution operators to Postmodern Harmonic Analysis, with strong functional analytic aspects, but also incorporating concepts from

  7. Harmonic analysis and the ``feel'' of a performance Introduction

    E-print Network

    Volk, Anja Fleischer

    Harmonic analysis and the ``feel'' of a performance Introduction This paper discusses a new discusses work of the author with RUBATO which concentrates on the harmonic analysis and its possible's architecture and go into detail regarding a harmonic analysis and performance of a particular piece, namely

  8. Analysis of Voiced Speech using Harmonic Models Yannis Stylianou

    E-print Network

    Greenberg, Albert

    Analysis of Voiced Speech using Harmonic Models Yannis Stylianou AT&T Labs Research, 180 Park Ave. This paper focuses on the harmonic analysis of speech. Three models are presented and compared. The first we will refer to all the other regions as ``unvoiced''. This paper focuses on the harmonic analysis

  9. Pulsed plasma measurement method using harmonic analysis

    NASA Astrophysics Data System (ADS)

    Kim, Yu-Sin; Kim, Dong-Hwan; Lee, Hyo-Chang; Chung, Chin-Wook

    2015-06-01

    A phase delay harmonic analysis method (PDHAM) with high-time resolution is proposed to measure the plasma parameters of the pulsed plasmas. The PDHAM, which is based on the floating harmonic method, applies the phase delayed voltages to a probe tip, and obtains each of the currents in the phase-domain at a given time. The time resolution of this method is 0.8 ?s, and the total measurement is done within 2 s in the case of a pulsed plasma with a frequency of 1 kHz. The measurement result of the plasma parameters was compared with a conventional Langmuir probe using a boxcar mode, and shows good agreements. Because this PDHAM can measure the plasma parameters even in the processing discharges, it is expected to be usefully applied to plasma diagnostics for pulsed processing plasmas.

  10. The physical librations of the moon, including higher harmonic effects

    NASA Technical Reports Server (NTRS)

    Kaula, W. M.; Baxa, P. A.

    1973-01-01

    The equations of the physical libration of the moon are developed using a representation of the earth-moon orbit as a Kepler ellipse referred to the lunar equator and expanding the lunar potential in terms of these Kepler elements. The Improved Lunar Ephemeris is used to calculate solar perturbations, and a linear integration of all effects arising from lunar gravitational harmonics through the fourth degree is performed. Aside from unobservable constant offsets of the principal axes, the main effects of the higher harmonics on longitude are: 10-sec six-yearly (argument omega), 1.2-sec three-yearly, 0.5-sec annual, and 0.1-sec monthly; on pole direction they are on the order of 0.5-sec six-yearly and 1.0-sec monthly. The higher harmonics must hence be taken into account in analyzing ranging data of 10 cm accuracy.

  11. Hemispherical Harmonic Surface Description and Applications to Medical Image Analysis

    E-print Network

    Huang, Heng

    Hemispherical Harmonic Surface Description and Applications to Medical Image Analysis Heng Huang Lebanon, NH 03756 Abstract The use of surface harmonics for rigid and nonrigid shape description is well known. In this paper we define a set of complete hemispherical harmonic basis functions on a hemisphere

  12. A Simple Analysis of the Harmonic Algorithm for Two Servers

    E-print Network

    Sgall, Jiri

    A Simple Analysis of the Harmonic Algorithm for Two Servers Marek Chrobak \\Lambda JiŸr'i Sgall y Abstract HARMONIC is a randomized k­server algorithm that chooses the servers with probabilities proportional to the inverses of distances to the request point. We present a simple proof that HARMONIC is 3

  13. Molecular Orbital Analysis of High Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Ohmura, Shu; Oyamada, Takayuki; Kato, Tsuyoshi; Kono, Hirohiko; Koseki, Shiro

    Tunnel ionization of molecules in an intense laser field and subsequent rescattering processes lead to high harmonic generation (HHG). Simultaneous tunneling from multiple orbitals has recently been observed which is not considered in the conventional single-active-electron model. To include such multielectron effects, we have developed a multiconfiguration method that uses time-dependent molecular orbitals. By energy analysis of the orbitals, we found that inner shell and valence shell orbitals interact with each other during the HHG process. The HHG spectra of multiple orbital paths originated from the interactions were calculated.

  14. Inconsistencies in the harmonic analysis applied to pulsating stars

    NASA Astrophysics Data System (ADS)

    Pascual-Granado, J.; Garrido, R.; Suárez, J. C.

    2015-05-01

    Harmonic analysis is the fundamental mathematical method used for the identification of pulsation frequencies in asteroseismology and other fields of physics. Here we introduce a test to evaluate the validity of the hypothesis in which Fourier theorem is based: the convergence of the expansion series. The huge number of difficulties found in the interpretation of the periodograms of pulsating stars observed by CoRoT and Kepler satellites lead us to test whether the function underlying these time series is analytic or not. Surprisingly, the main result is that these are originated from non-analytic functions, therefore, the condition for Parseval's theorem is not guaranteed.

  15. Harmonic analysis of nonlinear devices on spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Williamson, Frank; Sheble, Gerald B.

    1990-01-01

    A nonlinear device modeling algorithm (NOLID) has been developed for use in spacecraft power system analysis. This algorithm is designed to explore the effects of nonlinear devices and loads on a spacecraft power system. Application of this harmonic modeling algorithm in spacecraft power system management programs such as harmonic power flow analysis packages is discussed. It is shown that the NOLID algorithm can be applied in conjunction with a harmonic power flow to give a more accurate description of system state.

  16. Modular Approach to Physics: Simple Harmonic Motion - Weighted Spring

    NSDL National Science Digital Library

    2008-05-22

    This resource is a Java applet-based module relating to the simple harmonic motion produced by a block on a frictionless spring. It features a rich array of tools: motion graphs, energy graphs, vector components, reference circle, zoom toggle, and a data box that displays amplitude, angular frequency, displacement from equilibrium, phase angle, velocity, and acceleration of the oscillating block. Users control the spring constant, mass of the block, and amplitude of the oscillation. A comprehensive help section provides detailed directions and lesson ideas for instructors. This simulation is part of a larger collection of physics resources sponsored by the MAP project (Modular Approach to Physics).

  17. Geomagnetic main field analysis at the core-mantle boundary - Spherical harmonics compared with harmonic splines

    NASA Technical Reports Server (NTRS)

    Benton, E. R.; Kohl, Benjamin C.

    1986-01-01

    An optimum truncation level, N, in a spherical-harmonic analysis of the geomagnetic main field at the core-mantle boundary is determined by harmonic-spline analysis. Specifically, that value of N is found at which the two analyses are closest in a well defined sense and, for that value of N, the 'closeness' of two models is determined. Depending slightly on the definition of closeness, optimum N is found to be either 10 or 11. For those values the two analyses give remarkably similar results, showing that the conveniences of spherical harmonics can be retained with little penalty.

  18. -okfl ^ ORNL/CON-172 Linear Harmonic Analysis of Free-

    E-print Network

    Oak Ridge National Laboratory

    -okfl ^ ORNL/CON-172 OAK RIDGE NATIONAL LABORATORY Linear Harmonic Analysis of Free- Piston. #12;ORNL/CON-172 Engineering Technology Division* LINEAR HARMONIC ANALYSIS OF FREE-PISTON STIRLING/dynamic problem that is associated with a free-piston Stirling engine (FPSE). The governing equations

  19. Iron Loss Analysis of IPM Motor Considering Carrier Harmonics

    Microsoft Academic Search

    Katsumi Yamazaki; Yoshiaki Seto; Makoto Tanida

    2005-01-01

    In this paper, we investigate the iron loss of interior permanent magnet motors driven by PWM inverters using electromagnetic field analysis. Following 4 methods are applied: (1) Current input finite element method neglecting the carrier harmonics. (2) Voltage input finite element analysis neglecting carrier harmonics. (3) Current input finite element method with the measured armature current waveforms including the carrier

  20. Open Positions at the Numerical Harmonic Analysis Group (NuHAG) The Numerical Harmonic Analysis Group (NuHAG) looking for candidates for

    E-print Network

    Feichtinger, Hans Georg

    Open Positions at the Numerical Harmonic Analysis Group (NuHAG) The Numerical Harmonic Analysis Foundation. This project will study the interaction between frame theory and abstract harmonic analysis: The candidate should have a Ph. D. in mathematics and substantial experience in abstract harmonic analysis (some

  1. A Spherical Harmonic Analysis of Redshift Space

    E-print Network

    A. F. Heavens; A. N. Taylor

    1994-09-13

    We re-examine the effects of redshift space distortion in all-sky galaxy redshift surveys in the formalism of spherical harmonics. Within this framework we show how one can treat both the large-scale linear effects, and the small-scale nonlinear clustering, exactly to first order. The method also allows in principle a determination of the power spectrum of perturbations, requiring no assumptions beyond that of linear theory. The method therefore offers significant advantages over Fourier techniques when dealing with all-sky surveys. We apply our likelihood analysis to both simulated data, and real data, using the IRAS 1.2-Jy galaxy catalogue, for which we find a maximum likelihood $\\beta \\simeq 1.1\\pm 0.3$, and a real-space fluctuation amplitude corresponding to $\\sigma_{8,{\\rm IRAS}} = 0.68\\pm 0.05$.

  2. Harmonic analysis on the infinite symmetric group

    E-print Network

    Sergei Kerov; Grigori Olshanski; Anatoly Vershik

    2003-12-12

    Let S be the group of finite permutations of the naturals 1,2,... The subject of the paper is harmonic analysis for the Gelfand pair (G,K), where G stands for the product of two copies of S while K is the diagonal subgroup in G. The spherical dual to (G,K) (that is, the set of irreducible spherical unitary representations) is an infinite-dimensional space. For such Gelfand pairs, the conventional scheme of harmonic analysis is not applicable and it has to be suitably modified. We construct a compactification of S called the space of virtual permutations. It is no longer a group but it is still a G-space. On this space, there exists a unique G-invariant probability measure which should be viewed as a true substitute of Haar measure. More generally, we define a 1-parameter family of probability measures on virtual permutations, which are quasi-invariant under the action of G. Using these measures we construct a family {T_z} of unitary representations of G depending on a complex parameter z. We prove that any T_z admits a unique decomposition into a multiplicity free integral of irreducible spherical representations of (G,K). Moreover, the spectral types of different representations (which are defined by measures on the spherical dual) are pairwise disjoint. Our main result concerns the case of integral values of parameter z: then we obtain an explicit decomposition of T_z into irreducibles. The case of nonintegral z is quite different. It was studied by Borodin and Olshanski, see e.g. the survey math.RT/0311369.

  3. Harmonic analysis of current waveforms using optical current sensor

    Microsoft Academic Search

    W. C. Michie; A. Cruden; P. Niewczas; W. I. Madden; J. R. McDonald; M. Gauduin

    2001-01-01

    This work reports on the research and development of an optical current sensor for harmonic analysis within the electricity supply network. The device has a measurement capability, limited by the sampling frequency of the A\\/D converter, to around 20 kHz. We report on experimental verification of these measurements up to the 80th harmonic (4 kHz)

  4. Harmonic analysis of current waveforms using optical current sensor

    Microsoft Academic Search

    W. C. Michie; A. Cruden; P. Niewczas; W. I. Madden; J. R. McDonald; M. Gauduin

    2002-01-01

    This paper reports on the research and development of an optical current sensor for harmonic analysis within the electricity supply network. The device has a measurement capability, limited by the sampling frequency of the analog-to-digital converter, to around 20 kHz. We report on experimental verification of these measurements up to the 60th harmonic (3 kHz).

  5. Desynchronized Processing technique for Harmonic and interharmonic analysis

    Microsoft Academic Search

    Daniele Gallo; Roberto Langella; Alfredo Testa

    2004-01-01

    A new desynchronized processing technique for harmonic and interharmonic analysis that has general validity and results fully compatible with the IEC standard is presented. This technique is based on a double-stage signal processing procedure: In the first stage, the harmonic components are accurately estimated via interpolations in frequency domain and filtered away from the original signal so that in the

  6. MSA Comparative Crystal Chemistry The Analysis of Harmonic Displacement Factors

    E-print Network

    Downs, Robert T.

    1 MSA Comparative Crystal Chemistry Chapter 7 The Analysis of Harmonic Displacement Factors R of the displacement ellipsoids for a Si2O7 group in - quartz, SiO2, at 298 K and 838 K (Kihara, 1990). The ellipsoids be mathematically defined with a probability distribution function (p.d.f.). If we assume harmonic restoring forces

  7. Spherical harmonic analysis and synthesis for global multiresolution applications

    Microsoft Academic Search

    J. A. R. Blais; D. A. Provins

    2001-01-01

    On the Earth and in its neighborhood, spherical harmonic analysis and synthesis are standard mathematical procedures for scalar, vector and tensor fields. However, with the advent of multiresolution applications, additional considerations about convolu- tion filtering with decimation and dilation are required. As global applications often imply discrete observations on regular grids, computational challenges arise and conflicting claims about spherical harmonic

  8. Platonic polyhedra tune the 3-sphere: Harmonic analysis on simplices

    E-print Network

    Peter Kramer

    2009-01-02

    A spherical topological manifold of dimension n-1 forms a prototile on its cover, the (n-1)-sphere. The tiling is generated by the fixpoint-free action of the group of deck transformations. By a general theorem, this group is isomorphic to the first homotopy group. Multiplicity and selection rules appear in the form of reduction of group representations. A basis for the harmonic analysis on the (n-1)-sphere is given by the spherical harmonics which transform according to irreducible representations of the orthogonal group. The deck transformations form a subgroup, and so the representations of the orthogonal group can be reduced to those of this subgroup. Upon reducing to the identity representation of the subgroup, the reduced subset of spherical harmonics becomes periodic on the tiling and tunes the harmonic analysis on the (n-1)-sphere to the manifold. A particular class of spherical 3-manifolds arises from the Platonic polyhedra. The harmonic analysis on the Poincare dodecahedral 3-manifold was analyzed along these lines. For comparison we construct here the harmonic analysis on simplicial spherical manifolds of dimension n=1,2,3. Harmonic analysis applied to the cosmic microwave background by selection rules can provide evidence for multiply connected cosmic topologies.

  9. A Weighted Harmonic Means Analysis for the Proportional Unbalanced Design.

    ERIC Educational Resources Information Center

    Bonett, Douglas G.

    1982-01-01

    A weighted harmonic means analysis is presented that incorporates all of the available data, preserves the planned proportionality of the design, and avoids the problems associated with the replacement of missing data with sample estimates. (Author/BW)

  10. Aerodynamic Analysis of Cup Anemometers Performance: The Stationary Harmonic Response

    PubMed Central

    Pindado, Santiago; Cubas, Javier; Sanz-Andrés, Ángel

    2013-01-01

    The effect of cup anemometer shape parameters, such as the cups' shape, their size, and their center rotation radius, was experimentally analyzed. This analysis was based on both the calibration constants of the transfer function and the most important harmonic term of the rotor's movement, which due to the cup anemometer design is the third one. This harmonic analysis represents a new approach to study cup anemometer performances. The results clearly showed a good correlation between the average rotational speed of the anemometer's rotor and the mentioned third harmonic term of its movement. PMID:24381512

  11. Eigenvalue spectrum of the spheroidal harmonics: A uniform asymptotic analysis

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2015-06-01

    The spheroidal harmonics Slm (? ; c) have attracted the attention of both physicists and mathematicians over the years. These special functions play a central role in the mathematical description of diverse physical phenomena, including black-hole perturbation theory and wave scattering by nonspherical objects. The asymptotic eigenvalues {Alm (c) } of these functions have been determined by many authors. However, it should be emphasized that all the previous asymptotic analyzes were restricted either to the regime m ? ? with a fixed value of c, or to the complementary regime | c | ? ? with a fixed value of m. A fuller understanding of the asymptotic behavior of the eigenvalue spectrum requires an analysis which is asymptotically uniform in both m and c. In this paper we analyze the asymptotic eigenvalue spectrum of these important functions in the double limit m ? ? and | c | ? ? with a fixed m / c ratio.

  12. Spherical Harmonic Analysis of Particle Velocity Distribution Function: Comparison of Moments and Anisotropies using Cluster Data

    NASA Technical Reports Server (NTRS)

    Gurgiolo, Chris; Vinas, Adolfo F.

    2009-01-01

    This paper presents a spherical harmonic analysis of the plasma velocity distribution function using high-angular, energy, and time resolution Cluster data obtained from the PEACE spectrometer instrument to demonstrate how this analysis models the particle distribution function and its moments and anisotropies. The results show that spherical harmonic analysis produced a robust physical representation model of the velocity distribution function, resolving the main features of the measured distributions. From the spherical harmonic analysis, a minimum set of nine spectral coefficients was obtained from which the moment (up to the heat flux), anisotropy, and asymmetry calculations of the velocity distribution function were obtained. The spherical harmonic method provides a potentially effective "compression" technique that can be easily carried out onboard a spacecraft to determine the moments and anisotropies of the particle velocity distribution function for any species. These calculations were implemented using three different approaches, namely, the standard traditional integration, the spherical harmonic (SPH) spectral coefficients integration, and the singular value decomposition (SVD) on the spherical harmonic methods. A comparison among the various methods shows that both SPH and SVD approaches provide remarkable agreement with the standard moment integration method.

  13. Investigations of Low and Moderate Harmonic Fast Wave Physics on CDX-U

    NASA Astrophysics Data System (ADS)

    Spaleta, J.; Majeski, R.; Phillips, C. K.; Kaita, R.; Soukhanovskii, V.; Zakharov, L.; Rodgers, D.

    2002-11-01

    The physics of the low harmonic fast wave regime has been studied extensively in tokamak environments, but is largely unexplored for ST's which typically have high dielectric constant and higher ion beta than tokamaks. In this regime mode conversion to the IBW becomes significant(M. Ono. High Harmonic Fast Waves in High Beta Plasmas. Phys. Plasmas),2:4075, November 1995. Low harmonic fast wave heating studies are currently underway in CDX-U to investigate the potential for bulk ion heating. In preparation for these studies, the available RF power in CDX-U has been increased to ( ˜1/2 MW) and the operating frequency of the CDX RF transmitter was lowered to operate in the range of 8-10 MHz, providing access to the harmonics range 2?_i ˜4?i in hydrogen. A similar regime is accessible for the 30 MHz RF system on NSTX, at 0.6 Tesla in hydrogen. An analysis of preliminary experimental results on CDX-U together with with a summary of numerical and theoretical studies over the regimes of interest for NSTX and CDX-U will be presented.

  14. An electromagnetic time-harmonic analysis of shielded microstrip circuits

    Microsoft Academic Search

    JAMES C. RAUTIO; Roger F. Harrington

    1987-01-01

    A Galerkin analysis of microstrip circuits of arbitrary planar geometry enclosed in a rectangular conducting box is described. The technique entails a time-harmonic electromagnetic analysis evaluating all fields and surface currents. This analysis is suitable for the accurate verification of microstrip designs prior to fabrication. A computer program implementing the analysis has been written in Pascal on a personal computer.

  15. Spherical harmonic analysis of steady photospheric flows

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    1987-01-01

    A technique is presented in which full disk Doppler velocity measurements are analyzed using spherical harmonic functions to determine the characteristics of the spectrum of spherical harmonic modes and the nature of steady photospheric flows. Synthetic data are constructed in order to test the technique. In spite of the mode mixing due to the lack of information about the motions on the backside of the sun, solar rotation and differential rotation can be accurately measured and monitored for secular changes, and meridional circulations with small amplitudes can be measured. Furthermore, limb shift measurements can be accurately obtained, and supergranules can be fully resolved and separated from giant cells by their spatial characteristics.

  16. Quantum harmonic oscillator state synthesis and analysis

    E-print Network

    W. M. Itano; C. Monroe; D. M. Meekhof; D. Leibfried; B. E. King; D. J. Wineland

    1997-02-19

    Experiments are described in which a single, harmonically bound, beryllium ion in a Paul trap is put into Fock, thermal, coherent, squeezed, and Schroedinger cat states. Experimental determinations of the density matrix and the Wigner function are described. A simple calculation of the decoherence of a superposition of coherent states due to an external electric field is given.

  17. ANALYSIS-BY-SYNTHESIS LOW-RATE MULTIMODE HARMONIC SPEECH CODING

    E-print Network

    California at Santa Barbara, University of

    ANALYSIS-BY-SYNTHESIS LOW-RATE MULTIMODE HARMONIC SPEECH CODING Chunyan Li, Allen Gersho of harmonic coders. Therefore, in designing the proposed analysis- by-synthesis multimode harmonic coder (Ab, a generalized analysis-by-synthesis parameter estimation scheme in the harmonic coding framework is proposed

  18. STATISTICAL PARSING FOR HARMONIC ANALYSIS OF JAZZ CHORD Mark Granroth-Wilding, Mark Steedman

    E-print Network

    Steedman, Mark

    STATISTICAL PARSING FOR HARMONIC ANALYSIS OF JAZZ CHORD SEQUENCES Mark Granroth-Wilding, Mark- rical analyses. We focus here on harmonic analysis. We use a three- dimensional tonal harmonic space ([4 to apply techniques from NLP directly to the problem of harmonic analysis. We use a formal grammar of jazz

  19. Spherical harmonic analysis and synthesis for global multiresolution applications

    Microsoft Academic Search

    J. A. R. Blais; D. A. Provins

    2002-01-01

    .  ?On the Earth and in its neighborhood, spherical harmonic analysis and synthesis are standard mathematical procedures for\\u000a scalar, vector and tensor fields. However, with the advent of multiresolution applications, additional considerations about\\u000a convolution filtering with decimation and dilation are required. As global applications often imply discrete observations\\u000a on regular grids, computational challenges arise and conflicting claims about spherical harmonic transforms

  20. Harmonic Analysis: from Fourier to Haar Mara Cristina Pereyra

    E-print Network

    Pereyra, Cristina

    Harmonic Analysis: from Fourier to Haar Marâ??�a Cristina Pereyra Lesley A. Ward Department (T) 86 Chapter 6. A whirlwind tour of discrete Fourier and Haar analysis 89 6.1. Fourier Series.2. The wavelet transform 157 9.3. Haar analysis 159 9.4. Haar vs Fourier 171 9.5. Unconditional bases

  1. Analysis of enhanced second-harmonic generation in periodic nanostructures

    E-print Network

    Fainman, Yeshaiahu

    Analysis of enhanced second-harmonic generation in periodic nanostructures using modified rigorous coupled-wave analysis in the undepleted-pump approximation Wataru Nakagawa, Rong-Chung Tyan, and Yeshaiahu April 10, 2002; accepted April 16, 2002 We present an extension of the rigorous coupled-wave analysis

  2. Harmonic analysis of spacetime with hypercharge and isospin

    E-print Network

    Heinrich Saller

    2003-12-09

    In analogy to the harmonic analysis for the Poincar\\'e group with its irreducible representations characterizing free particles, the harmonic analysis for a nonlinear spacetime model as homogenous space of the extended Lorentz group GL(C^2) is given. What the Dirac energy-momentum measures are for free particles, are multipole measures in the analysis of nonlinear spacetime - they are related to spacetime interactions. The representations induced from the nonlinear spacetime fixgroup U(2) connect representations of external (spacetimelike) degrees of freedom with those of internal (hypercharge-isospinlike) ones as seen in the standard model of electroweak and strong interactions. The methods used are introduced and exemplified with the nonrelativistic Kepler dynamics in an interpretation as harmonic analysis of time and position functions.

  3. Spherical harmonic analysis of a model-generated climatology

    NASA Technical Reports Server (NTRS)

    Christidis, Z. D.; Spar, J.

    1981-01-01

    Monthly mean fields of 850 mb temperature (T850), 500 mb geopotential height (G500) and sea level pressure (SLP) were generated in the course of a five-year climate simulation run with a global general circulation model. Both the model-generated climatology and an observed climatology were subjected to spherical harmonic analysis, with separate analyses of the globe and the Northern Hemisphere. Comparison of the dominant harmonics of the two climatologies indicates that more than 95% of the area-weighted spatial variance of G500 and more than 90% of that of T850 are explained by fewer than three components, and that the model adequately simulates these large-scale characteristics. On the other hand, as many as 25 harmonics are needed to explain 95% of the observed variance of SLP, and the model simulation of this field is much less satisfactory. The model climatology is also evaluated in terms of the annual cycles of the dominant harmonics.

  4. Harmonic analysis and an empirical model for TEC over Palehua

    Microsoft Academic Search

    K. Unnikrishnan; R Balachandran Nair; Chandu Venugopal

    2002-01-01

    An empirical model of total electron content (TEC) for a low-latitude station, Palehua, has been developed using harmonic analysis of TEC data measured at this station during the period 1980–1990; the TEC data were obtained from Faraday rotation measurements of linearly polarised signals transmitted by geostationary satellites. The analysis reveals that monthly mean values of the daily mean and the

  5. Asymptotic spectrum of the oblate spin-weighted spheroidal harmonics: a WKB analysis

    E-print Network

    Shahar Hod

    2013-04-02

    Spin-weighted spheroidal harmonics play a central role in the mathematical description of diverse physical phenomena, including black-hole perturbation theory and wave scattering. We present a novel and compact derivation of the asymptotic eigenvalues of these important functions. Our analysis is based on a simple trick which transforms the corresponding spin-weighted spheroidal angular equation into a Schr\\"odinger-like wave equation which is amenable to a standard WKB analysis.

  6. Harmonic analysis on a galois field and its subfields

    E-print Network

    A. Vourdas

    2006-10-17

    Complex functions $\\chi (m)$ where $m$ belongs to a Galois field $GF(p^ \\ell)$, are considered. Fourier transforms, displacements in the $GF(p^ \\ell) \\times GF(p^ \\ell)$ phase space and symplectic $Sp(2,GF(p^ \\ell))$ transforms of these functions are studied. It is shown that the formalism inherits many features from the theory of Galois fields. For example, Frobenius transformations are defined which leave fixed all functions $h(n)$ where $n$ belongs to a subfield $GF(p^ d)$ of the $GF(p^ \\ell)$. The relationship between harmonic analysis (or quantum mechanics) on $GF(p^ \\ell)$ and harmonic analysis on its subfields, is studied.

  7. Vertex-IRF transformations, dynamical quantum groups and harmonic analysis

    E-print Network

    Jasper V. Stokman

    2003-05-23

    It is shown that a dynamical quantum group arising from a vertex-IRF transformation has a second realization with untwisted dynamical multiplication but nontrivial bigrading. Applied to the $\\hbox{SL}(2;\\mathbb{C})$ dynamical quantum group, the second realization is naturally described in terms of Koornwinder's twisted primitive elements. This leads to an intrinsic explanation why harmonic analysis on the ``classical'' $\\hbox{SL}(2;\\mathbb{C})$ quantum group with respect to twisted primitive elements, as initiated by Koornwinder, is the same as harmonic analysis on the $\\hbox{SL}(2;\\mathbb{C})$ dynamical quantum group.

  8. Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals

    E-print Network

    Cheng, Harry H.

    Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals Hong was modulated and wavelet analyses of the absorption data were performed. It was observed that harmonic wavelets could simultaneously extract the 1f and 2f harmonics as well as higher-order harmonics from the direct

  9. AN OVERVIEW OF HARMONIC ANALYSIS ON THE GROUP OF ISOMETRIES

    E-print Network

    Cowling, Michael

    present some of the features of harmonic analysis on G associated with the * *Abel transformation 1 #12; of the horocyclical Radon transformation on X, which we call the Abel transform* *ation]. In the radial case we derive an inversion formula which is only slightly di* *fferent from that described

  10. Analysis of Different Harmonic and Intermodulation Distortions for CATV Systems

    NASA Astrophysics Data System (ADS)

    Singh, Sandeep; Kamaljit, Singh Bhatia; Anurag, Sharma; Kaur, Harsimrat

    2015-06-01

    In this paper, after examining all the basic design issues of CATV systems, prominent distortions like harmonic and intermodulation distortions are taken into account for different order. Besides outer distortions for CATV sources, inner distortion of relative intensity to noise is disabled for current analysis.

  11. High-Speed Video Analysis of Damped Harmonic Motion

    ERIC Educational Resources Information Center

    Poonyawatpornkul, J.; Wattanakasiwich, P.

    2013-01-01

    In this paper, we acquire and analyse high-speed videos of a spring-mass system oscillating in glycerin at different temperatures. Three cases of damped harmonic oscillation are investigated and analysed by using high-speed video at a rate of 120 frames s[superscript -1] and Tracker Video Analysis (Tracker) software. We present empirical data for…

  12. Harmonic analysis on local fields and adelic spaces. II

    NASA Astrophysics Data System (ADS)

    Osipov, Denis V.; Parshin, Aleksei N.

    2011-08-01

    We develop harmonic analysis in certain categories of filtered Abelian groups and vector spaces. The objects of these categories include local fields and adelic spaces arising from arithmetic surfaces. We prove some structure theorems for quotients of the adèle groups of algebraic and arithmetic surfaces.

  13. The harmonic oscillator, dimensional analysis and inflationary solutions

    E-print Network

    Sandro Silva e Costa

    2002-12-06

    In this work, focused on the production of exact inflationary solutions using dimensional analysis, it is shown how to explain inflation from a pragmatic and basic point of view, in a step-by-step process, starting from the one-dimensional harmonic oscillator.

  14. A Spherical Harmonic Analysis of the Earth's Topography

    Microsoft Academic Search

    Georges Balmino; Kurt Lambeck; William M. Kaula

    1973-01-01

    This letter is a correction to the letter of the same title by Lee and Kaula [1967]. In 1971 two independent harmonic analyses of the topography at Meudon and Los Angeles found the results of Lee and Kaula [1967] to be incorrect. The error of the 1967 analysis has since been found to be an insufficient dimension (W. H. K.

  15. Harmonic analysis of the Ha velocity field of NGC 4254

    E-print Network

    Laurent Chemin; Olivier Hernandez; Chantal Balkowski; Claude Carignan; Philippe Amram

    2005-12-20

    The ionized gas kinematics of the Virgo Cluster galaxy NGC 4254 (Messier 99) is analyzed by an harmonic decomposition of the velocity field into Fourier coefficients. The aims of this study are to measure the kinematical asymmetries of Virgo cluster galaxies and to connect them to the environment. The analysis reveals significant $m=1,2,4$ terms which origins are discussed.

  16. Harmonic Analysis and Convex Geometry, Fall 2013, September 27.

    E-print Network

    Ryabogin, Dmitry

    Harmonic Analysis and Convex Geometry, Fall 2013, September 27 ellipsoid in R3 centered at the origin has a disc as one o* *f its central sections (by the plane passing through the origin). b) Prove that any d-dimensional ellipsoid in Rdcentered at the origin has

  17. Harmonic Analysis and Convex Geometry, Fall 2013, September 27.

    E-print Network

    Ryabogin, Dmitry

    Harmonic Analysis and Convex Geometry, Fall 2013, September 27. Instructor: Dmitry Ryabogin incident to the vertex and all the vertices are equivalent). 3. Problem 3. a) Prove that any ellipsoid in R the origin). b) Prove that any d-dimensional ellipsoid in Rd centered at the origin has a k-dimensional ball

  18. Harmonic Analysis, Real Approximation, and the Communication Complexity of

    E-print Network

    Grolmusz, Vince

    Harmonic Analysis, Real Approximation, and the Communication Complexity of Boolean Functions Vince Grolmusz \\Lambda June 14, 1996 Abstract The 2--party communication complexity of Boolean function f of the communication matrix, depends on the L 1 norm of function f , for arbitrary Boolean func­ tion f . 1

  19. Measures of Boolean Function Complexity Based on Harmonic Analysis

    Microsoft Academic Search

    Anna Bernasconi; Bruno Codenotti

    1994-01-01

    In this paper We study some measures of complexity for Boolean functions based on Abstract Harmonic Analysis. More precisely, we extend the notion of average sensitivity of Boolean functions and introduce the generalized sensitivity (or k-sensitivity) which accounts for the changes in the function value when k input bits are flipped. We find the connection between k-sensitivity and Fourier coefficients.

  20. Circular current loops, magnetic dipoles and spherical harmonic analysis.

    USGS Publications Warehouse

    Alldredge, L.R.

    1980-01-01

    Spherical harmonic analysis (SHA) is the most used method of describing the Earth's magnetic field, even though spherical harmonic coefficients (SHC) almost completely defy interpretation in terms of real sources. Some moderately successful efforts have been made to represent the field in terms of dipoles placed in the core in an effort to have the model come closer to representing real sources. Dipole sources are only a first approximation to the real sources which are thought to be a very complicated network of electrical currents in the core of the Earth. -Author

  1. ON INTERACTIONS BETWEEN HARMONIC ANALYSIS AND THE THEORY OF AUTOMORPHIC FORMS

    E-print Network

    Tadic, Marko

    ON INTERACTIONS BETWEEN HARMONIC ANALYSIS AND THE THEORY OF AUTOMORPHIC FORMS MARKO TADI´C Abstract. In this paper we review some connections between harmonic analysis and the modern theory of automorphic forms. We indicate in some examples how the study of problems of harmonic analysis brings us

  2. Representation Discovery in Planning using Harmonic Analysis Jeff Johns and Sarah Osentoski and Sridhar Mahadevan

    E-print Network

    Massachusetts at Amherst, University of

    Representation Discovery in Planning using Harmonic Analysis Jeff Johns and Sarah Osentoski of AI as well. This paper describes a novel harmonic analysis framework for planning based on estimating on recent work in harmonic analysis, a sub- field of mathematics that includes traditional Fourier

  3. COMPUTATIONAL HARMONIC ANALYSIS FOR TENSOR FIELDS ON THE TWO-SPHERE

    E-print Network

    Kostelec, Peter J.

    COMPUTATIONAL HARMONIC ANALYSIS FOR TENSOR FIELDS ON THE TWO-SPHERE PETER KOSTELEC, DAVID K. MASLEN harmonics. This relation was used for analysis of shallow water models by C. Temperton [64] to reduce the completion of some of this work. 2. Harmonic analysis on the two-dimensional sphere Since the scalar

  4. LINEAR TIME PERIODIC MODELLING OF POWER ELECTRONIC DEVICES FOR POWER SYSTEM HARMONIC ANALYSIS AND SIMULATION

    E-print Network

    Boyer, Edmond

    LINEAR TIME PERIODIC MODELLING OF POWER ELECTRONIC DEVICES FOR POWER SYSTEM HARMONIC ANALYSIS for modelling and analysis of multi-converter systems. In order to take the harmonic interactions into account by better precision, but are too complicated for being applied for harmonic analysis when the system

  5. NON-SPHERICAL MICROPHONE ARRAY STRUCTURES FOR 3D BEAMFORMING AND SPHERICAL HARMONIC ANALYSIS

    E-print Network

    Abhayapala, Thushara D.

    NON-SPHERICAL MICROPHONE ARRAY STRUCTURES FOR 3D BEAMFORMING AND SPHERICAL HARMONIC ANALYSIS, and spatial sound- field recording. The spherical harmonic analysis of the 3D acoustic field, which-y plane. 2. SOUNDFIELD ANALYSIS 2.1. Spherical harmonic expansion A soundfield at a point (r

  6. Where We Are At With p Harmonic Measure Conference on Complex Analysis

    E-print Network

    Lewis, John

    Where We Are At With p Harmonic Measure John Lewis Conference on Complex Analysis University Kentucky) Where We Are At With p Harmonic Measure Conference on Complex Analysis University o / 197 #12 differential equations, harmonic analysis, and quasi-regular mappings in space. Many of the problems I look

  7. Harmonic analysis with respect to heat kernel measure

    E-print Network

    Brian C. Hall

    2000-06-07

    I review certain results in harmonic analysis for systems whose configuration space is a compact Lie group. The results described involve a heat kernel measure, which plays the same role as a Gaussian measure on Euclidean space. The main constructions are group analogs of the Hermite expansion, the Segal-Bargmann transform, and the Taylor expansion. The results are related to geometric quantization, to stochastic analysis, and to the quantization of 1+1-dimensional Yang-Mills theory.

  8. A note about Norbert Wiener and his contribution to Harmonic Analysis and Tauberian Theorems

    NASA Astrophysics Data System (ADS)

    Almira, J. M.; Romero, A. E.

    2009-05-01

    In this note we explain the main motivations Norbert Wiener had for the creation of his Generalized Harmonic Analysis [13] and his Tauberian Theorems [14]. Although these papers belong to the most pure mathematical tradition, they were deeply based on some Engineering and Physics Problems and Wiener was able to use them for such diverse areas as Optics, Brownian motion, Filter Theory, Prediction Theory and Cybernetics.

  9. Harmonic inversion analysis of exceptional points in resonance spectra

    E-print Network

    Jacob Fuchs; Jörg Main; Holger Cartarius; Günter Wunner

    2014-02-17

    The spectra of, e.g. open quantum systems are typically given as the superposition of resonances with a Lorentzian line shape, where each resonance is related to a simple pole in the complex energy domain. However, at exceptional points two or more resonances are degenerate and the resulting non-Lorentzian line shapes are related to higher order poles in the complex energy domain. In the Fourier-transform time domain an $n$-th order exceptional point is characterised by a non-exponentially decaying time signal given as the product of an exponential function and a polynomial of degree $n-1$. The complex positions and amplitudes of the non-degenerate resonances can be determined with high accuracy by application of the nonlinear harmonic inversion method to the real-valued resonance spectra. We extend the harmonic inversion method to include the analysis of exceptional points. The technique yields, in the energy domain, the amplitudes of the higher order poles contributing to the spectra, and, in the time domain, the coefficients of the polynomial characterising the non-exponential decay of the time signal. The extended harmonic inversion method is demonstrated on two examples, viz. the analysis of exceptional points in resonance spectra of the hydrogen atom in crossed magnetic and electric fields, and an exceptional point occurring in the dynamics of a single particle in a time-dependent harmonic trap.

  10. Harmonic Analysis of Polynomial Threshold Functions

    Microsoft Academic Search

    Jehoshua Bruck

    1990-01-01

    The analysis of linear threshold Boolean functions has recently attracted the attention of those interested in circuit complexity as well as of those interested in neural networks. Here a generalization of linear threshold functions is defined, namely, polynomial threshold functions, and its relation to the class of linear threshold functions is investigated. A Boolean function is polynomial threshold if it

  11. Article for the `Handbook of Global Analysis', Elsevier (2007, to appear) HARMONIC MAPS

    E-print Network

    Hélein, Frédéric - Institut de Mathématiques de Jussieu, Université Paris 7

    Article for the `Handbook of Global Analysis', Elsevier (2007, to appear) HARMONIC MAPS Fr of harmonic maps between given manifolds. Thus we shall survey some of the main methods of global analysis´ed´eric H´elein and John C. Wood Introduction The subject of harmonic maps is vast and has found many

  12. Li-Yau inequalities for positive harmonic functions by Stochastic Analysis

    E-print Network

    Driver, Bruce

    Li-Yau inequalities for positive harmonic functions by Stochastic Analysis Marc Arnaudon a , Bruce harmonic functions on Riemannian manifolds by using methods of Stochastic Analysis. Rather than evaluating an exact Bismut formula for the differential of a harmonic function, our method relies on a Bismut type

  13. Analysis of the harmonizing potential of order processing attributes in spread production systems

    E-print Network

    Paris-Sud XI, Université de

    Analysis of the harmonizing potential of order processing attributes in spread production systems: classification systems, attribute and data harmonization, analysis of potential, order processing 1 Introduction. The paper discusses an approach how to measure the competitive advantage of harmonized order processing data

  14. Surface Alignment of 3D Spherical Harmonic Models: Application to Cardiac MRI Analysis

    E-print Network

    Huang, Heng

    Surface Alignment of 3D Spherical Harmonic Models: Application to Cardiac MRI Analysis Heng Huang1 of spherical harmonic basis functions for a fast implementa- tion. Applications of medical image analysis (e@cs.dartmouth.edu Abstract. The spherical harmonic (SPHARM) description is a powerful surface modeling technique that can

  15. Explorations of the Harmonic Series Appendix to A Radical Approach to Real Analysis 2nd

    E-print Network

    California at Santa Cruz, University of

    Explorations of the Harmonic Series Appendix to A Radical Approach to Real Analysis 2nd edition c to A Radical Approach to Real Analysis 2nd edition. c 2006 David M. Bressoud #12;Explorations of the Harmonic(n) Figure 1: A leaning--but stable--stack of bricks. 1 #12;Explorations of the Harmonic Series 2 0 1 23

  16. Topology of Platonic Spherical Manifolds: From Homotopy to Harmonic Analysis

    E-print Network

    Kramer, Peter

    2015-01-01

    We carry out the harmonic analysis on four Platonic spherical three-manifolds with different topologies. Starting out from the homotopies (Everitt 2004), we convert them into deck operations, acting on the simply connected three-sphere as the cover, and obtain the corresponding variety of deck groups. For each topology, the three-sphere is tiled into copies of a fundamental domain under the corresponding deck group. We employ the point symmetry of each Platonic manifold to construct its fundamental domain as a spherical orbifold. While the three-sphere supports an~orthonormal complete basis for harmonic analysis formed by Wigner polynomials, a given spherical orbifold leads to a selection of a specific subbasis. The resulting selection rules find applications in cosmic topology, probed by the cosmic microwave background.

  17. Topology of Platonic Spherical Manifolds: From Homotopy to Harmonic Analysis

    E-print Network

    Peter Kramer

    2015-04-05

    We carry out the harmonic analysis on four Platonic spherical three-manifolds with different topologies. Starting out from the homotopies (Everitt 2004), we convert them into deck operations, acting on the simply connected three-sphere as the cover, and obtain the corresponding variety of deck groups. For each topology, the three-sphere is tiled into copies of a fundamental domain under the corresponding deck group. We employ the point symmetry of each Platonic manifold to construct its fundamental domain as a spherical orbifold. While the three-sphere supports an~orthonormal complete basis for harmonic analysis formed by Wigner polynomials, a given spherical orbifold leads to a selection of a specific subbasis. The resulting selection rules find applications in cosmic topology, probed by the cosmic microwave background.

  18. Application of harmonic analysis in the measuring technique of corrosion

    SciTech Connect

    Meszaros, L.; Meszaros, G.; Lengyel, B. (Hungarian Academy of Sciences, Budaoersi (Hungary). Research Lab. for Inorganic Chemistry)

    1994-08-01

    A technique for the determination of the rate of corrosion is described based on the harmonic analysis of the current of the electrode perturbed with relatively small amplitude undistorted sinusoidal alternating voltage. The measurement carried out in the vicinity of the corrosion potential permits the determination of both the corrosion current density and the Tafel slopes. The technique is illustrated using a study of the corrosion of various types of iron electrodes in acidic and neutral media.

  19. Harmonic analysis with respect to heat kernel measure

    Microsoft Academic Search

    Brian C. Hall

    2000-01-01

    I review certain results in harmonic analysis for systems whose configuration\\u000aspace is a compact Lie group. The results described involve a heat kernel\\u000ameasure, which plays the same role as a Gaussian measure on Euclidean space.\\u000aThe main constructions are group analogs of the Hermite expansion, the\\u000aSegal-Bargmann transform, and the Taylor expansion. The results are related to\\u000ageometric

  20. Mesoscale harmonic analysis of homogenous dislocation nucleation

    E-print Network

    Asad Hasan; Craig E. Maloney

    2012-05-08

    We perform atomistic computer simulations to study the mechanism of homogeneous dislocation nucleation in two dimensional (2D) hexagonal crystalline films during indentation with a circular nanoindenter. The nucleation process is governed by the vanishing of the energy associated with a single normal mode. This critical mode is largely confined to a single plane of adjacent atoms. For fixed film thickness, L, the spatial extent, \\xi, of the critical mode grows with indenter radius, R. For fixed R/L, the spatial extent \\xi, grows roughly as \\xi ~ L^0.4. We, furthermore, perform a mesoscale analysis to determine the lowest energy normal mode for mesoscale regions of varying radius, r_{meso}, centered on the critical mode's core. The energy, \\lambda_{meso}, of the lowest normal mode in the meso-region decays very rapidly with r_{meso} and \\lambda_{meso} ~= 0 for r_{meso} >~ \\xi. The lowest normal mode shows a spatial extent, \\xi_{meso}, which has a sublinear power-law increase with r_{meso} for r_{meso} analysis of small regions, r_{meso} analysis gives good estimates for the energy and spatial extent of the critical mode \\emph{only} for r_{meso} >~ 1.5 \\xi. In this sense homogeneous dislocation nucleation should be understood as a quasi-local phenomenon.

  1. HFAST - A harmonic analysis program for Stirling cycles

    NASA Technical Reports Server (NTRS)

    Huang, S. C.

    1992-01-01

    HFAST is a general-purpose third-order harmonic analysis and design program for predicting the cyclic-steady state thermodynamic performance of Stirling cycles. It represents the state-of-the-art results of years of research efforts at Mechanical Technology Inc. (MTI) in the development of Stirling cycle machines. The code has been extensively used at MTI to support the development of both free-piston and kinematic Stirling cycle machines. Lately, HFAST has undergone many major improvements, both in the analysis method and in the user's interface. This paper presents a brief description of the current analysis method used in HFAST.

  2. Analysis of Low-Momentum Correlations with Cartesian Harmonics

    E-print Network

    P. Danielewicz; S. Pratt

    2005-05-18

    Exploiting final-state interactions and/or identity interference, analysis of anisotropic correlations of particles at low-relative velocities yields information on the anisotropy of emission sources in heavy-ion reactions. We show that the use of cartesian surface-spherical harmonics in such analysis allows for a systematic expansion of the correlations in terms of real angular-moment coefficients dependent on relative momentum. The coefficients are directly related to the analogous coefficients for emission sources. We illustrate the analysis with an example of correlations generated by classical Coulomb interaction.

  3. Numerical Analysis of Fifth-Harmonic Conversion of Low-Power Pulsed Nd:YAG Laser with Resonance of Second Harmonic

    E-print Network

    Kung, Andy

    Numerical Analysis of Fifth-Harmonic Conversion of Low-Power Pulsed Nd:YAG Laser with Resonance cavity resonating at the second harmonic has been developed. Numerical analysis is performed to show of Second Harmonic Lien-Bee CHANG1Ã , S. C. WANG1 and A. H. KUNG1;2 1 Institute of Electro

  4. IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 44, NO. 6, OCTOBER 1998 2435 Data Compression and Harmonic Analysis

    E-print Network

    Vetterli, Martin

    and Harmonic Analysis David L. Donoho, Martin Vetterli, Fellow, IEEE, R. A. DeVore, and Ingrid Daubechies harmonic analysis and data compression. The story goes back of course to Shannon's R(D) theory in the case to the Information Theory community, growing out of the field of harmonic analysis. Recent harmonic analysis

  5. 1034 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 18, NO. 3, JULY 2003 Direct Harmonic Analysis of the

    E-print Network

    Lehn, Peter W.

    1034 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 18, NO. 3, JULY 2003 Direct Harmonic Analysis to the harmonic analysis of a STATCOM. Index Terms--FACTS, harmonic analysis, pulsewidth modula- tion, STATCOM. I- cept of space vector-based harmonic analysis is presented with the help of a simple example, assuming

  6. Venus gravity - A harmonic analysis and geophysical implications

    NASA Technical Reports Server (NTRS)

    Mottinger, N. A.; Sjogren, W. L.; Bills, B. G.

    1985-01-01

    An improved theoretical model of Venusian global gravity has been obtained by fitting a tenth degree spherical harmonic series to 78 orbital arcs of Doppler tracking data from the Pioneer Venus Orbiter. Maps of the free-air anomaly and its formal error are presented. Isostatic anomaly and 'Geoid' maps are also presented, and their geophysical implications are discussed in details. Comparison with equivalent resolution topographic models reveals a strong correlation between long wavelength gravity and the topography of Venus. Analysis of the second degree harmonics showed two aspects of the orientation of the inertial axes of Venus: (1) a significant (about three degrees) departure of the axis of greatest inertia from the rotational axis; and (2) a near alignment of the axis of least inertia with the location of the subterrestrial point at the time of the next inferior conjunction with earth (December 16, 2101). A series of contour maps of the Venusian free-air anomalies is provided.

  7. BAYESIAN ANALYSIS OF MULTIPLE HARMONIC OSCILLATIONS IN THE SOLAR CORONA

    SciTech Connect

    Arregui, I.; Asensio Ramos, A.; Diaz, A. J., E-mail: iarregui@iac.es [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain)

    2013-03-01

    The detection of multiple mode harmonic kink oscillations in coronal loops enables us to obtain information on coronal density stratification and magnetic field expansion using seismology inversion techniques. The inference is based on the measurement of the period ratio between the fundamental mode and the first overtone and theoretical results for the period ratio under the hypotheses of coronal density stratification and magnetic field expansion of the wave guide. We present a Bayesian analysis of multiple mode harmonic oscillations for the inversion of the density scale height and magnetic flux tube expansion under each of the hypotheses. The two models are then compared using a Bayesian model comparison scheme to assess how plausible each one is given our current state of knowledge.

  8. Theoretical analysis of high-harmonic generation in solids.

    PubMed

    Vampa, G; McDonald, C R; Orlando, G; Klug, D D; Corkum, P B; Brabec, T

    2014-08-15

    We investigate theoretically high-harmonic generation (HHG) in bulk crystals exposed to intense midinfrared lasers with photon energies smaller than the band gap. The two main mechanisms, interband and intraband HHG, are explored. Our analysis indicates that the interband current neglected so far is the dominant mechanism for HHG. Saddle point analysis in the Keldysh limit yields an intuitive picture of interband HHG in solids similar to atomic HHG. Interband and intraband HHG exhibit a fundamentally different wavelength dependence. This signature can be used to experimentally distinguish between the two mechanisms in order to verify their importance. PMID:25170708

  9. Theoretical Analysis of High-Harmonic Generation in Solids

    NASA Astrophysics Data System (ADS)

    Vampa, G.; McDonald, C. R.; Orlando, G.; Klug, D. D.; Corkum, P. B.; Brabec, T.

    2014-08-01

    We investigate theoretically high-harmonic generation (HHG) in bulk crystals exposed to intense midinfrared lasers with photon energies smaller than the band gap. The two main mechanisms, interband and intraband HHG, are explored. Our analysis indicates that the interband current neglected so far is the dominant mechanism for HHG. Saddle point analysis in the Keldysh limit yields an intuitive picture of interband HHG in solids similar to atomic HHG. Interband and intraband HHG exhibit a fundamentally different wavelength dependence. This signature can be used to experimentally distinguish between the two mechanisms in order to verify their importance.

  10. NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES

    E-print Network

    Bartels, Soeren

    NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES S ¨OREN BARTELS Abstract. This article studies the numerical approximation of harmonic maps into surfaces and its global convergence to a discrete harmonic map is proved under general conditions. Weak

  11. POPULATION ECOLOGY -ORIGINAL PAPER Spatial analysis of harmonic oscillation of gypsy moth

    E-print Network

    Liebhold, Andrew

    POPULATION ECOLOGY - ORIGINAL PAPER Spatial analysis of harmonic oscillation of gypsy moth outbreak periodicity in the intensity of gypsy moth out- breaks is largely a result of harmonic oscillations in gypsy pattern of periodicity in gypsy moth popula- tions is that 5- and 10-year cycles are harmonics

  12. Statistical analysis of VLF radio emissions triggered by power line harmonic radiation and observed

    E-print Network

    Santolik, Ondrej

    Statistical analysis of VLF radio emissions triggered by power line harmonic radiation and observed electromagnetic emissions triggered by Power Line Harmonic Radiation (PLHR), the man-made waves emitted at harmonics of 50 or 60 Hz. They look like rising tones or hooks with a starting frequency associated

  13. Spherical Harmonic Analysis and Model-Limited Extrapolation on the Sphere

    E-print Network

    Zhang, Wen

    Spherical Harmonic Analysis and Model-Limited Extrapolation on the Sphere: Integral Equation characterization. This is well-known and involves truncating the spherical harmonic expansion of the signal on the sphere retaining the lowest order terms [4], [5]. The spherical harmonics do involve two indices and we

  14. Potential for Protein Surface Shape Analysis Using Spherical Harmonics and 3D Zernike Descriptors

    E-print Network

    Kihara, Daisuke

    REVIEW Potential for Protein Surface Shape Analysis Using Spherical Harmonics and 3D Zernike representations with specific focus on two schemes namely spherical harmonics and their exten- sion, the 3D Spherical harmonics Introduction Understanding protein structure and its relation to the various biological

  15. Analysis of the Harmonic Algorithm for Three Servers Marek Chrobak z Ji r Sgall yz

    E-print Network

    Sgall, Jiri

    Analysis of the Harmonic Algorithm for Three Servers Marek Chrobak #3;z Ji#20;r#19;#16; Sgall yz Abstract Harmonic is a randomized k-server algorithm that, at each step, given a request point r, chooses, it is known that the competitive ratio of Harmonic is at least 1 2 k(k + 1), while the best upper bound

  16. Article for the `Handbook of Global Analysis', Elsevier (2007, to appear) HARMONIC MAPS

    E-print Network

    Hélein, Frédéric - Institut de Mathématiques de Jussieu, Université Paris 7

    Article for the `Handbook of Global Analysis', Elsevier (2007, to appear) HARMONIC MAPS Frâ?? ed of harmonic maps between given manifolds. Thus we shall survey some of the main methods of global analysisâ?? eric Hâ?? elein and John C. Wood Introduction The subject of harmonic maps is vast and has found many

  17. POWER ELECTRONICS HARMONIC ANALYSIS BASED ON THE LINEAR TIME PERIODIC MODELING. APPLICATIONS FOR AC/DC/AC POWER

    E-print Network

    Paris-Sud XI, Université de

    1 POWER ELECTRONICS HARMONIC ANALYSIS BASED ON THE LINEAR TIME PERIODIC MODELING. APPLICATIONS harmonics can not be expressed. In the frequency domain, several methods for power network harmonic analysis methods are the most often used in the network harmonic analysis. They are simple, but not accurate

  18. RF physics of ICWC discharge at high cyclotron harmonics

    SciTech Connect

    Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M. [Association Euratom-Belgian State, LPP-ERM-KMS, 1000 Brussels (Belgium); Bobkov, V.; Rohde, V.; Schneider, P. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Douai, D.; Kogut, D. [Association Euratom-CEA, CEA, IRFM, 13108 St Paul lez Durance (France); Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G. [Association Euratom-IEK-4, Forschungszentrum Jülich, 52425 Jülich (Germany); Moiseenko, V. [Institute of Plasma Physics NSC KIPT, 61108 Kharkiv (Ukraine); Noterdaeme, J.-M. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching, Germany and Ghent University, 9000 Ghent (Belgium); Collaboration: TEXTOR Team; ASDEX Upgrade Team

    2014-02-12

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,?=?{sub H+}, and with its high cyclotron harmonics (HCH), ?=10?{sub cH+}? HCH scenario: very high antenna coupling to low density RF plasmas (P{sub pl}?0.9P{sub RF-G}) and low energy Maxwellian distribution of CX hydrogen atoms with temperature T{sub H}?350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E{sub ?H} ?1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of B{sub T}-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low T{sub e} plasmas is studied at fundamental ICR and its high harmonics.

  19. Harmonic Analysis (I) e-mail fang@math.ncku.edu.tw

    E-print Network

    Fang, Yung-Fu

    99 2 () Harmonic Analysis (I) L166010 3 e-mail fang@math.ncku.edu.tw 275 Algebras An Introduction to Harmonic Analysis( Chapter 1 - 8) by Yitzhak Katznelson Real Analysis transform on the line and the related Fourier analysis We expect to grab the basic idea and concept

  20. Modeling and analysis of hysteresis by harmonic balance method

    NASA Astrophysics Data System (ADS)

    Cheng, Weiying; Saito, Yoshifuru

    2015-05-01

    B-H loop and its modeling are essential for ferromagnetic material characterization and electromagnetic simulation. The objective of this study was to characterize material change by analyzing the corresponding B-H loops and construct a general B-H model for electromagnetic simulation. A B-H loop was decomposed in terms of either ideal or normal magnetization curves, and the respective curves are single-valued functions of B and dB, which can be constructed using harmonic balance method. The B-H loop analysis and modeling were simplified by the loop decomposition approach.

  1. Investigations into the performance of various HBV physical structures for high efficiency harmonic generation

    Microsoft Academic Search

    W. H. Chow; D. P. Steenson

    2003-01-01

    Heterostructure barrier varactors (HBV) with different physical structures have been investigated and characterised for their capacitance-voltage characteristic and device series resistance. This is a novel concept to increase the HBV capacitance modulation whilst minimize the device series resistance for the NLTL in achieving optimum harmonic generation. Various capacitance modulation characteristics can be engineered by shaping the HBV mesa with either

  2. THE JOURNAL OF CHEMICAL PHYSICS 139, 165104 (2013) Exploring chemical reaction mechanisms through harmonic Fourier beads

    E-print Network

    2013-01-01

    THE JOURNAL OF CHEMICAL PHYSICS 139, 165104 (2013) Exploring chemical reaction mechanisms through understanding of complex chemical transformations relies on the identification of elementary reactions involved the harmonic Fourier beads (HFB) path optimization method to study chemical re- actions involving covalent bond

  3. Phase-matching analysis of high-order harmonics generated by truncated Bessel beams in the sub-10-fs regime

    SciTech Connect

    Altucci, C. [Coherentia-INFM UdR di Napoli and Universita 'Federico II', Dipartimento di Scienze Fisiche-Complesso di Monte S. Angelo, via Cintia, 80126 Naples (Italy); Dipartimento di Chimica, Universita della Basilicata, Potenza, (Italy); Bruzzese, R.; De Lisio, C. [Coherentia-INFM UdR di Napoli and Universita 'Federico II', Dipartimento di Scienze Fisiche-Complesso di Monte S. Angelo, via Cintia, 80126 Naples (Italy); Nisoli, M.; Priori, E.; Stagira, S. [Ultras-INFM UdR di Milano, Dipartimento di Fisica, Politecnico di Milano, Milan (Italy); Pascolini, M.; Poletto, L.; Villoresi, P. [Laboratory for Ultraviolet and X-ray Optical Research-INFM DEI-Universita di Padova, Padova (Italy); Tosa, V. [Laser Technology Laboratory, RIKEN (Japan); National Institute for R and D in Isotopic and Molecular Technology, Cluj-Napoca (Romania); Midorikawa, K. [Laser Technology Laboratory, RIKEN (Japan)

    2003-09-01

    We describe a very simple physical model that allows the analysis of high-order harmonic generation in gases when the pumping laser beam has an intensity profile that is not Gaussian but truncated Bessel. This is the typical experimental condition when sub-10-fs pump-laser pulses, generated by the hollow fiber compression technique, are used. This model is based on the analysis of the phase-matching conditions for the harmonic generation process revisited in view of the new spatial mode of the fundamental beam. In particular, the role of the atomic dipole phase and the geometric phase terms are evidenced both for harmonics generated in the plateau and in the cutoff spectral regions. The influence of dispersion introduced by free electrons produced by laser ionization has also been discussed in some detail. Spatial patterns of far-field harmonics are then obtained by means of a simplified algorithm which allows one to avoid the numerical integration of the harmonic beam propagation equation. Experimental spatial distributions and divergence angles of high-order harmonics generated in Ne with 7-fs titanium-sapphire pulses are compared with numerical simulations in various experimental conditions. The agreement between measurements and calculated results is found to be very satisfactory.

  4. Three dimensional modelling and numerical analysis of super-radiant harmonic emission in FEL (optical klystron)

    SciTech Connect

    Gover, A.; Friedman, A.; Luccio, A.

    1986-09-01

    A full 3-D Analysis of super-radiant (bunched electron) free electron harmonic radiation is presented. A generalized form of the FEL pendulum equation was derived and numerically solved. Both spectral and phasor formulation were developed to treat the radiation in the time domain. In space the radiation field is expanded in terms of either a set of free space discrete modes or plane waves. The numerical solutions reveal some new distinctly 3-D effects to which we provide a physical explanation. 12 refs., 9 figs., 5 tabs.

  5. EXPONENTIAL RADON TRANSFORM INVERSION BASED ON HARMONIC ANALYSIS OF THE EUCLIDEAN MOTION GROUP

    E-print Network

    Yazici, Birsen

    EXPONENTIAL RADON TRANSFORM INVERSION BASED ON HARMONIC ANALYSIS OF THE EUCLIDEAN MOTION GROUP Can Engineering Troy, NY ABSTRACT This paper presents a new method for the exponential Radon trans- form inversion based on harmonic analysis of the Euclidean mo- tion group (M(2)). The exponential Radon transform

  6. RADON TRANSFORM INVERSION BASED ON HARMONIC ANALYSIS OF THE EUCLIDEAN MOTION GROUP

    E-print Network

    Yazici, Birsen

    RADON TRANSFORM INVERSION BASED ON HARMONIC ANALYSIS OF THE EUCLIDEAN MOTION GROUP Can Evren Yarman of the projection slice theorem using harmonic analysis of the Euclidean motion group (M(N)). The Radon transform to new algo- rithms for the inversion of the Radon transform. 1. INTRODUCTION The Radon transform forms

  7. ANALYSIS OF A FINITE ELEMENT PML APPROXIMATION FOR THE THREE DIMENSIONAL TIME-HARMONIC MAXWELL

    E-print Network

    Pasciak, Joseph

    ANALYSIS OF A FINITE ELEMENT PML APPROXIMATION FOR THE THREE DIMENSIONAL TIME-HARMONIC MAXWELL. Maxwell's equations, Helmholtz equation, time-harmonic acoustic and elec- tromagnetic scattering, div for the truncated domain problem is derived. This is a critical estimate for the finite element analysis which we

  8. Dynamic Steady-State Analysis of Structures under Uncertain Harmonic Loads

    E-print Network

    Kanno, Yoshihiro

    Dynamic Steady-State Analysis of Structures under Uncertain Harmonic Loads via Semidefinite Program.5 -1 -0.5 -7.5 -7 -6.5 -6 -5.5 u (cm) u y (cm) x bounding ellipsoid #12;motivation (static analysis -- harmonic excitation s consider the uncertainty of f s predict the distribution of u s do not use the 1st

  9. Analysis of rotor vibratory loads using higher harmonic pitch control

    NASA Technical Reports Server (NTRS)

    Quackenbush, Todd R.; Bliss, Donald B.; Boschitsch, Alexander H.; Wachspress, Daniel A.

    1992-01-01

    Experimental studies of isolated rotors in forward flight have indicated that higher harmonic pitch control can reduce rotor noise. These tests also show that such pitch inputs can generate substantial vibratory loads. The modification is summarized of the RotorCRAFT (Computation of Rotor Aerodynamics in Forward flighT) analysis of isolated rotors to study the vibratory loading generated by high frequency pitch inputs. The original RotorCRAFT code was developed for use in the computation of such loading, and uses a highly refined rotor wake model to facilitate this task. The extended version of RotorCRAFT incorporates a variety of new features including: arbitrary periodic root pitch control; computation of blade stresses and hub loads; improved modeling of near wake unsteady effects; and preliminary implementation of a coupled prediction of rotor airloads and noise. Correlation studies are carried out with existing blade stress and vibratory hub load data to assess the performance of the extended code.

  10. Harmonic analysis in a power system with wind generation

    Microsoft Academic Search

    Stavros A. Papathanassiou; Michael P. Papadopoulos

    2006-01-01

    Variable-speed wind turbines inject harmonic currents in the network, which may potentially create voltage distortion problems. In this paper, a case study is presented for a 10-MW wind farm, intended to be connected to a network with extended high-voltage submarine cable lines. First, the system modeling approach and the harmonic load-flow calculation is described. Then, the harmonic impedance of the

  11. Analysis and Design of New Harmonic Mitigation Approaches 

    E-print Network

    Aeloiza Matus, Eddy 1972-

    2012-11-01

    -pulse rectifiers are based on the principle of harmonic cancellation through phase shifting and are the preferred solution to eliminate harmonics in high power converters in large motor drives, electro-winning rectifiers and HVDC transmission systems [23...-voltage systems can have up to 2.0% THD where the cause is an HVDC terminal that will attenuate by the time it is tapped for user. Individual Harmonic Order (Odd Harmonics) Isc / IL <11 11 ? h"? 17 17 ? h"? 23 23 ? h"? 35 h"? 35 TDD <20 * 4.0 2...

  12. Harmonic analysis of spacecraft power systems using a personal computer

    NASA Technical Reports Server (NTRS)

    Williamson, Frank; Sheble, Gerald B.

    1989-01-01

    The effects that nonlinear devices such as ac/dc converters, HVDC transmission links, and motor drives have on spacecraft power systems are discussed. The nonsinusoidal currents, along with the corresponding voltages, are calculated by a harmonic power flow which decouples and solves for each harmonic component individually using an iterative Newton-Raphson algorithm. The sparsity of the harmonic equations and the overall Jacobian matrix is used to an advantage in terms of saving computer memory space and in terms of reducing computation time. The algorithm could also be modified to analyze each harmonic separately instead of all at the same time.

  13. Harmonic analysis of music using combinatory categorial grammar 

    E-print Network

    Granroth-Wilding, Mark Thomas; Wilding, Mark Thomas Granroth

    2013-11-28

    Various patterns of the organization of Western tonal music exhibit hierarchical structure, among them the harmonic progressions underlying melodies and the metre underlying rhythmic patterns. Recognizing these structures ...

  14. Conformational deformability of RNA: a harmonic mode analysis.

    PubMed Central

    Zacharias, M; Sklenar, H

    2000-01-01

    The harmonic mode analysis method was used to characterize the conformational deformability of regular Watson-Crick paired, mismatch- and bulge-containing RNA. Good agreement between atomic Debye-Waller factors derived from x-ray crystallography of a regular RNA oligonucleotide and calculated atomic fluctuations was obtained. Calculated helical coordinate fluctuations showed a small sequence dependence of up to approximately 30-50%. A negative correlation between motions at a given base pair step and neighboring steps was found for most helical coordinates. Only very few calculated modes contribute significantly to global motions such as bending, twisting, and stretching of the RNA molecules. With respect to a local helical description of the RNA helix our calculations suggest that RNA bending is mostly due to a periodic change in the base pair step descriptors slide and roll. The presence of single guanine:uridine or guanine:adenine mismatches had little influence on the calculated RNA flexibility. In contrast, for tandem guanine:adenine base pairs the harmonic mode approach predicts a significantly reduced conformational flexibility in the case of a sheared arrangement and slightly enhanced flexibility for a face-to-face (imino proton) pairing relative to regular RNA. The presence of a single extra adenine bulge nucleotide stacked between flanking sequences resulted in an increased local atomic mobility around the bulge site (approximately 40%) and a slightly enhanced global bending flexibility. For an adenine bulge nucleotide in a looped-out conformation a strongly enhanced bulge nucleotide mobility but no increased bending flexibility compared to regular RNA was found. PMID:10777750

  15. Thyroidectomy using the harmonic scalpel: Analysis of 105 consecutive cases

    Microsoft Academic Search

    Larry Shemen

    2002-01-01

    Objective: The purpose of this report was to evaluate the technical benefits, if any, of thyroidectomy using the harmonic scalpel versus conventional thyroidectomy. Study Design: One hundred five consecutive patients underwent thyroidectomy over 1 year with use of the harmonic scalpel. They were compared with a group of 20 patients who underwent thyroidectomy 1 year earlier using conventional techniques. Results:

  16. ANALYSIS OF A FINITE PML APPROXIMATION FOR THE THREE DIMENSIONAL TIME-HARMONIC MAXWELL AND ACOUSTIC

    E-print Network

    Gilbert, Robert P.

    ANALYSIS OF A FINITE PML APPROXIMATION FOR THE THREE DIMENSIONAL TIME-HARMONIC MAXWELL AND ACOUSTIC layer (PML) (cf. [1] and [2]). We also treat the time-harmonic PML approximation to the acoustic of the frequency domain three dimensional Maxwell scattering problem using a truncated domain perfectly matched

  17. A Newton solution for the harmonic phasor analysis of ac\\/dc converters

    Microsoft Academic Search

    B. C. Smith; N. R. Watson; A. R. Wood; J. Arrillaga

    1996-01-01

    The steady state equations that describe the converter and dc system in the harmonic domain are solved by means of Newton`s method, in a manner suitable for embedding in an iterative harmonic analysis of the complete power system. The solution includes the interaction of the converter with the dc system, and the effect of variation in the firing and end

  18. Harmonic Analysis of a Three-Phase Diode Bridge Rectifier based on Sampled-Data Model

    E-print Network

    Lehn, Peter W.

    Harmonic Analysis of a Three-Phase Diode Bridge Rectifier based on Sampled-Data Model K. L. Lian is to incorporate it into a harmonic power flow program to yield improved accuracy. Index Terms-- Diode Bridge. INTRODUCTION THREE phase diode bridge rectifiers are often used in industry to provide the dc input voltage

  19. ISMIR 2008 Session 4c Automatic Music Analysis and Transcription RESOLVING OVERLAPPING HARMONICS FOR MONAURAL MUSICAL

    E-print Network

    Wang, DeLiang "Leon"

    ISMIR 2008 ­ Session 4c ­ Automatic Music Analysis and Transcription RESOLVING OVERLAPPING HARMONICS FOR MONAURAL MUSICAL SOUND SEPARATION USING PITCH AND COMMON AMPLITUDE MODULATION John Woodruff of overlapping harmonics poses a significant challenge to monaural musi- cal sound separation systems

  20. A new frequency domain arc furnace model for iterative harmonic analysis

    Microsoft Academic Search

    J. G. Mayordomo; L. F. Beites; R. Asensi; M. Izzeddine; L. Zabala; J. Amantegui

    1997-01-01

    This paper presents a new frequency domain Arc Furnace model for Iterative Harmonic Analysis (IHA) by means of a Newton method. Powerful analytical expressions for harmonic currents and their derivatives are obtained under the balanced conditions of the system. The model offers a three phase configuration where there is no path for homopolar currents. Moreover, it contemplates continuous and discontinuous

  1. Spectral analysis of harmonic tremor signals at Mt. Semeru volcano, Indonesia

    Microsoft Academic Search

    Vera Schlindwein; Joachim Wassermann; Frank Scherbaum

    1995-01-01

    A detailed spectral analysis of tremor signals recorded at Mt. Semeru volcano, Indonesia, in October 1992 by the German-Indonesian Volcano Expedition (GIVE'92) reveals clearly harmonic spectra containing up to 11 integer harmonics. The spectral features can be explained by any rhythmically pulsating source producing a temporarily stable source signal. As one realization of this concept we model the source as

  2. Motions and pattern analysis: harmonic analysis on motion groups and their homogeneous spaces

    Microsoft Academic Search

    Jean-Paul Gauthier; Guy Bornard; Martine Silbermann

    1991-01-01

    Fourier-like transforms that are defined on several groups of motions on the plane and on the plane itself (viewed as the homogeneous space of these motion groups) are presented. These transforms should have many applications in the area of pattern recognition, detection, and the representation of motions in pattern analysis. The method is based upon group-representation theory and abstract harmonic

  3. Time-frequency analysis and Harmonic Gaussian Functions

    E-print Network

    Tokiniaina Ranaivoson; Raoelina Andriambololona; Rakotoson Hanitriarivo

    2013-08-08

    A method for time-frequency analysis is given. The approach utilizes properties of Gaussian distribution, properties of Hermite polynomials and Fourier analysis. We begin by the definitions of a set of functions called harmonic Gaussian functions. Then these functions are used to define a set of transformations,noted T_n, which associate to a function {\\psi},of the time variable t, a set of functions {\\Psi}_n which depend on time, frequency and frequency (or time) standard deviation. Some properties of the transformations T_n and the functions {\\Psi}_n are given. It is proved in particular that the square of the modulus of each function {\\Psi}_n can be interpreted as a representation of the energy distribution of the signal, represented by the function {\\psi}, in the time-frequency plane for a given value of the frequency (or time) standard deviation. It is also shown that the function {\\psi}, can be recovered from the functions{\\Psi}_n.

  4. PHYSICAL REVIEW A 90, 063412 (2014) Effect of nuclear vibration on high-order-harmonic generation of aligned H2

    E-print Network

    Chu, Shih-I

    2014-01-01

    PHYSICAL REVIEW A 90, 063412 (2014) Effect of nuclear vibration on high-order-harmonic generation of aligned H2 + molecules Dmitry A. Telnov,1,* John Heslar,2, and Shih-I Chu2,3, 1 Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia 2 Department of Physics, Center for Quantum

  5. Wavelength modulation spectroscopy-digital detection of gas absorption harmonics based on Fourier analysis.

    PubMed

    Mei, Liang; Svanberg, Sune

    2015-03-20

    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method. PMID:25968506

  6. Analysis of the harmonic gyrotron traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Kuo, S. C.; Cheo, B. R.; Lee, M. C.

    1986-01-01

    A single nonlinear differential equation is derived for describing the spatial evolution of the wave field in a gyrotron amplifier on the cylindrical guide geometry. The equation is then used to determine the efficiencies and the optimized interaction lengths for gyrotron operated with TE sub N1 modes at the N-th cyclotron harmonic. The equation offers a significant advantage in simplifying numerical work in comparison with the brute force particle simulation approach. The efficiencies of the harmonic operations by using a hollow beam decrease quickly with increasing harmonic number, but are enhanced by using an axis-encircling beam instead.

  7. Physics analysis workstation

    SciTech Connect

    Johnstad, H.

    1989-06-01

    The Physics Analysis Workstation (PAW) is a high-level program providing data presentation and statistical or mathematical analysis. PAW has been developed at CERN as an instrument to assist physicists in the analysis and presentation of their data. The program is interfaced to a high level graphics package, based on basic underlying graphics. 3-D graphics capabilities are being implemented. The major objects in PAW are 1 or 2 dimensional binned event data with fixed number of entries per event, vectors, functions, graphics pictures, and macros. Command input is handled by an integrated user interface package, which allows for a variety of choices for input, either with typed commands, or in a tree structure menu driven mode. 6 refs., 1 fig.

  8. Spherical harmonic analysis of steady photospheric flows. II

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    1992-01-01

    The use of the spherical harmonic functions to analyze the nearly steady flows in the solar photosphere is extended to situations in which B(0) the latitude at disk center, is nonzero and spurious velocities are present. The procedures for extracting the rotation profile and meridional circulation are altered to account for the seasonal tilt of the sun's rotation axis toward and away from the observer. A more robust and accurate method for separating the limb shift and meridional circulation signals is described. The analysis procedures include the ability to mask out areas containing spurious velocities (velocity-like signals that do not represent true flow velocities in the photosphere). The procedures are shown to work well in extracting the various flow components from realistic artificial data with a broad, continuous spectrum for the supergranulation. The presence of this supergranulation signal introduces errors of a few m/s in the measurements of the rotation profile, meridional circulation, and limb shift from a single Doppler image.

  9. Analysis of cyclotron harmonic emissions at the outer planets

    NASA Technical Reports Server (NTRS)

    Roth, I.; Hudson, M. K.

    1992-01-01

    The flyby missions of Voyagers 1 and 2 at Jupiter, Saturn and Uranus revealed intense waves above the electron gyrofrequency. Observation of waves at the upper hybrid frequency is often accompanied by power at adjacent electron Bernstein harmonics, and the relative power in these modes depends both on the density and temperature ratios of the cold background electron population and the hot magnetospheric electrons which drive the instability. A model of electron distributions which is consistent with observations is used for analysis of the excited waves, their dependence upon plasma parameters, and the time scales of the saturation processes. It is shown that in the presence of two-temperature electron distributions the linear excitation is due to a fluidlike coupling of two eigenmodes for perpendicular propagation and to kinetic destalization of oblique modes. The dependence of linear growth rates on propagation angle is presented, along with results from particle simulations. A quasi-linear diffusion time for relaxing the hot electron loss cone is calculated and compared with simulation results. This time scale is faster than for local saturation by heating the cold population, and also the convective amplification time scale, suggesting that the waves saturate at quasi-linear levels, while being convectively localized to the equatorial regions of the outer planetary magnetospheres.

  10. Non-Harmonic Analysis Applied to Optical Coherence Tomography Imaging

    NASA Astrophysics Data System (ADS)

    Cao, Xu; Uchida, Tetsuya; Hirobayashi, Shigeki; Chong, Changho; Morosawa, Atsushi; Totsuka, Koki; Suzuki, Takuya

    2012-02-01

    A new processing technique called non-harmonic analysis (NHA) is proposed for optical coherence tomography (OCT) imaging. Conventional Fourier-domain OCT employs the discrete Fourier transform (DFT), which depends on the window function and length. The axial resolution of the OCT image, calculated by using DFT, is inversely proportional to the full width at half maximum (FWHM) of the wavelength range. The FWHM of wavelength range is limited by the sweeping range of the source in swept-source OCT and it is limited by the number of CCD pixels in spectral-domain OCT. However, the NHA process does not have such constraints; NHA can resolve high frequencies irrespective of the window function and the frame length of the sampled data. In this study, the NHA process is described and it is applied to OCT imaging. It is compared with OCT images based on the DFT. To demonstrate the benefits of using NHA for OCT, we perform OCT imaging with NHA of an onion skin. The results reveal that NHA can achieve an image resolution equivalent that of a 100-nm sweep range using a significantly reduced wavelength range. They also reveal the potential of using this technique to achieve high-resolution imaging without using a broadband source. However, the long calculation times required for NHA must be addressed if it is to be used in clinical applications.

  11. Optical coherence tomography imaging based on non-harmonic analysis

    NASA Astrophysics Data System (ADS)

    Cao, Xu; Hirobayashi, Shigeki; Chong, Changho; Morosawa, Atsushi; Totsuka, Koki; Suzuki, Takuya

    2009-11-01

    A new processing technique called Non-Harmonic Analysis (NHA) is proposed for OCT imaging. Conventional Fourier-Domain OCT relies on the FFT calculation which depends on the window function and length. Axial resolution is counter proportional to the frame length of FFT that is limited by the swept range of the swept source in SS-OCT, or the pixel counts of CCD in SD-OCT degraded in FD-OCT. However, NHA process is intrinsically free from this trade-offs; NHA can resolve high frequency without being influenced by window function or frame length of sampled data. In this study, NHA process is explained and applied to OCT imaging and compared with OCT images based on FFT. In order to validate the benefit of NHA in OCT, we carried out OCT imaging based on NHA with the three different sample of onion-skin,human-skin and pig-eye. The results show that NHA process can realize practical image resolution that is equivalent to 100nm swept range only with less than half-reduced wavelength range.

  12. Physical Culture, Physical Education and Relational Analysis

    Microsoft Academic Search

    David Kirk

    1999-01-01

    This paper argues for the recovery of a notion of physical culture that can serve the purposes of relational analysis in social research. The recovery of the notion is undertaken through a brief etymology of the term, and through an historical overview of shifts in physical culture during the twentieth century. The recovered notion is described as one dimension of

  13. Spherical harmonic analysis for verfication of a global atmospheric model

    NASA Technical Reports Server (NTRS)

    Christidis, Z.; Spar, J.

    1979-01-01

    Surface spherical harmonics were used to analyze the horizontal fields of various quantities generated by a global climate model. Also, the computed monthly mean forecast fields were compared with the corresponding observed fields.

  14. Harmonic Analysis of Linear Fields on the Nilgeometric Cosmological Model

    E-print Network

    Masayuki Tanimoto

    2004-09-04

    To analyze linear field equations on a locally homogeneous spacetime by means of separation of variables, it is necessary to set up appropriate harmonics according to its symmetry group. In this paper, the harmonics are presented for a spatially compactified Bianchi II cosmological model -- the nilgeometric model. Based on the group structure of the Bianchi II group (also known as the Heisenberg group) and the compactified spatial topology, the irreducible differential regular representations and the multiplicity of each irreducible representation, as well as the explicit form of the harmonics are all completely determined. They are also extended to vector harmonics. It is demonstrated that the Klein-Gordon and Maxwell equations actually reduce to systems of ODEs, with an asymptotic solution for a special case.

  15. Analytic scaling analysis of high harmonic generation conversion efficiency

    E-print Network

    Falcao-Filho, Edilson L.

    Closed form expressions for the high harmonic generation (HHG) conversion efficiency are obtained for the plateau and cutoff regions. The presented formulas eliminate most of the computational complexity related to HHG ...

  16. Platonic polyhedra tune the 3-sphere: II. Harmonic analysis on cubic spherical 3-manifolds

    E-print Network

    Peter Kramer

    2009-03-01

    From the homotopy groups of two cubic spherical 3-manifolds we construct the isomorphic groups of deck transformations acting on the 3-sphere. These groups become the cyclic group of order eight and the quaternion group respectively. By reduction of representations from the orthogonal group to the identity representation of these subgroups we provide two subgroup-periodic bases for the harmonic analysis on the 3-manifolds. This harmonic analysis has applications to cosmic topology.

  17. Analysis of Harmonic Damping Effect of the Distributed Active Filter System

    NASA Astrophysics Data System (ADS)

    Cheng, Po-Tai; Lee, Tzung-Lin

    The harmonic resonance in the power distribution system or in the industrial facilities has been reported. The harmonic termination by installing a shunt active filter at the end of a radial line can suppress harmonic resonance; however, the harmonic voltage distortion along the line may still be significant due to harmonics standing waves. The distributed active filter system, which consists of multiple active filter units deployed along the power line, can effectively reduce voltage harmonics. Based on the pre-determined droop characteristics, the active filter units can share harmonic filtering workload without any communications. In this paper, the distributed active filter system is applied to a radial distribution line and a loop distribution line, which is often used in high-tech industrial parks for enhancing power reliability. This paper provides the theoretic analysis of harmonic resonance, simulation results and laboratory test results to verify the performance of the distributed active filter system. The deployment strategies of active filter units are also presented.

  18. Extracting tidal frequencies using multivariate harmonic analysis of sea level height time series

    NASA Astrophysics Data System (ADS)

    Amiri-Simkooei, A. R.; Zaminpardaz, S.; Sharifi, M. A.

    2014-10-01

    This contribution is seen as a first attempt to extract the tidal frequencies using a multivariate spectral analysis method applied to multiple time series of tide-gauge records. The existing methods are either physics-based in which the ephemeris of Moon, Sun and other planets are used, or are observation-based in which univariate analysis methods—Fourier and wavelet for instance—are applied to tidal observations. The existence of many long tide-gauge records around the world allows one to use tidal observations and extract the main tidal constituents for which efficient multivariate methods are to be developed. This contribution applies the multivariate least-squares harmonic estimation (LS-HE) to the tidal time series of the UK tide-gauge stations. The first 413 harmonics of the tidal constituents and their nonlinear components are provided using the multivariate LS-HE. A few observations of the research are highlighted: (1) the multivariate analysis takes information of multiple time series into account in an optimal least- squares sense, and thus the tidal frequencies have higher detection power compared to the univariate analysis. (2) Dominant tidal frequencies range from the long-term signals to the sixth-diurnal species interval. Higher frequencies have negligible effects. (3) The most important tidal constituents (the first 50 frequencies) ordered from their amplitudes range from 212 cm (M2) to 1 cm (OQ2) for the data set considered. There are signals in this list that are not available in the 145 main tidal frequencies of the literature. (4) Tide predictions using different lists of tidal frequencies on five different data sets around the world are compared. The prediction results using the first significant 50 constituents provided promising results on these locations of the world.

  19. Consideration of space harmonics in complex finite element analysis of induction motors with an air-gap interface coupling

    Microsoft Academic Search

    Y. Ouazir; N. Takorabet; R. Ibtiouen; S. Mezani

    2006-01-01

    A method for coupling the stator and rotor fields of induction motors in time harmonic finite element (FE) analysis with consideration of space harmonics is presented. The coupling scheme is derived from Fourier series of the magnetic vector potential at air-gap interface conditions. A transformation technique is used to introduce the coupling scheme in the saturated time harmonic FEs model

  20. A Newton solution for the harmonic phasor analysis of ac/dc converters

    SciTech Connect

    Smith, B.C.; Watson, N.R.; Wood, A.R.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand)

    1996-04-01

    The steady state equations that describe the converter and dc system in the harmonic domain are solved by means of Newton`s method, in a manner suitable for embedding in an iterative harmonic analysis of the complete power system. The solution includes the interaction of the converter with the dc system, and the effect of variation in the firing and end of commutation angles caused by ac voltage and dc current harmonics. The convergence of Newton`s method is investigated, and methods for accelerating the solution are implemented. Finally, the solution obtained is validated by means of time domain simulation.

  1. Brownian Motion and Harmonic Analysis on Sierpinski Carpets

    Microsoft Academic Search

    Martin T. Barlow; Richard F. Bass

    1999-01-01

    We consider a class of fractal subsets of Rd formed in a manner analogous to the construction of the Sierpinski carpet. We prove a uniform Harnack inequality for positive harmonic functions; study the heat equation, and obtain upper and lower bounds on the heat kernel which are, up to constants, the best possible; construct a locally isotropic diffusion X and

  2. Application of Harmonic Analysis to the Theory of Synchronous Machines

    Microsoft Academic Search

    Waldo V. Lyon

    1918-01-01

    It is shown that the flux distribution in the air gap of a synchronous machine consists of a series of component distributions that are simple harmonic wave trains, either stationary or moving at constant velocities. Methods are suggested for determining the effects of slots and the saturation of the magnetic circuit on the magnitudes of these component distributions. Expressions for

  3. Harmonic analysis of total electron contents time series: methodology and results

    Microsoft Academic Search

    A. R. Amiri-Simkooei; J. Asgari

    2011-01-01

    In an attempt to model regular variations of the ionosphere, the least-squares harmonic estimation is applied to the time\\u000a series of the total electron contents (TEC) provided by the JPL analysis center. Multivariate and modulated harmonic estimation\\u000a spectra are introduced and estimated for the series to detect the regular and modulated dominant frequencies of the periodic\\u000a patterns. Two significant periodic

  4. Geometric diffusions as a tool for harmonic analysis and structure definition of data: Multiscale methods

    E-print Network

    of the space. It can be thought of as global Fourier analysis. The multiscale analysis proposed hereGeometric diffusions as a tool for harmonic analysis and structure definition of data: Multiscale, CT 06510; and Department of Computer Science, Yale University, 51 Prospect Street, New Haven, CT

  5. Semiclassical analysis of long-wavelength multiphoton processes: The periodically driven harmonic oscillator

    E-print Network

    Vela-Arevalo, Luz V.

    Semiclassical analysis of long-wavelength multiphoton processes: The periodically driven harmonic to obtain a nonperturbative analysis. When applied to the standard vector potential coupling, an exact application of the Goeppert- Mayer gauge. While the analysis to this point is general and aimed at microwave

  6. Analysis of higher harmonic contamination with a modified approach using a grating analyser

    SciTech Connect

    Gupta, Rajkumar, E-mail: rkg@rract.gov.in; Modi, Mohammed H.; Lodha, G. S. [X-ray Optics Section, Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)] [X-ray Optics Section, Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India); Kumar, M.; Chakera, J. A. [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)] [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2014-04-15

    Soft x-ray spectra of the toroidal grating monochromator (TGM) at the reflectivity beamline of Indus-1 synchrotron source are analyzed for higher harmonic contribution. A diffraction grating of central line spacing 1200 l/mm is used to disperse the monochromatic beam received from TGM to quantify the harmonic contents in the 50–360 Å wavelength range. In order to calculate the harmonic contamination, conventionally the intensity of higher order peak is divided by first order peak intensity of the desired wavelength. This approach is found to give wrong estimate as first order peak itself is overlapped by higher order peaks. In the present study, a modified approach has been proposed to calculate harmonic contamination where the intensity contributions of overlapping orders have been removed from the first order diffraction peak of the desired wavelength. It is found that the order contamination in the TGM spectra is less than 15% in the wavelength range of 90–180 Å. The total harmonic contribution increases from 6%–60% in the wavelength range of 150–260 Å. The critical wavelength of Indus-1 is 61 Å hence the harmonic contamination below 90 Å is significantly low. The results obtained with modified approach match well with those obtained by quantitative analysis of multilayer reflectivity data. The obtained higher harmonics data are used to fit the transmission of aluminum edge filter in the 120–360 Å wavelength range.

  7. ATOMIC AND MOLECULAR PHYSICS: Phase-dependent quantum interference between different pathways in bichromatic harmonic generation

    NASA Astrophysics Data System (ADS)

    Cai, Jun; Wang, Li-Ming; Qiao, Hao-Xue

    2009-04-01

    This paper studies the harmonic generation of the hydrogen atom subjected to a collinear bichromatic laser field by numerically solving the time-dependent Schrödinger equation using the split-operator pseudo-spectral method. By adding a frequency variation to the additional field, the contributions of different pathways to particular order harmonic generation can be isolated. The quantum interference pattern between harmonic pathways, which influences the harmonic intensity, is found to be either constructive or destructive with respect to different relative phase of the two field components. Detailed description of up to the 35th-order harmonics and the harmonic pathways for a wide range of field parameters is presented.

  8. Analysis of harmonic spline gravity models for Venus and Mars

    NASA Technical Reports Server (NTRS)

    Bowin, Carl

    1986-01-01

    Methodology utilizing harmonic splines for determining the true gravity field from Line-Of-Sight (LOS) acceleration data from planetary spacecraft missions was tested. As is well known, the LOS data incorporate errors in the zero reference level that appear to be inherent in the processing procedure used to obtain the LOS vectors. The proposed method offers a solution to this problem. The harmonic spline program was converted from the VAX 11/780 to the Ridge 32C computer. The problem with the matrix inversion routine that improved inversion of the data matrices used in the Optimum Estimate program for global Earth studies was solved. The problem of obtaining a successful matrix inversion for a single rev supplemented by data for the two adjacent revs still remains.

  9. Physically Based Rendering Fourier Analysis

    E-print Network

    Kazhdan, Michael

    Physically Based Rendering (600.657) Sampling #12;Fourier Analysis · Fourier analysis provides;Fourier Analysis · As higher frequency components are added to the approximation, finer details are captured. Initial Function 0th Order Approximation 0th Order Component f() f0()=a0ei0 #12;Fourier Analysis

  10. Comparison Among Three Harmonic Analysis Techniques on the Sphere and the Ellipsoid

    NASA Astrophysics Data System (ADS)

    Abd-Elmotaal, Hussein; Abd-Elbaky, Mostafa; Seitz, Kurt; Heck, Bernhard

    2014-04-01

    The paper presents a comparison among three different techniques for harmonic analysis on the sphere and the ellipsoid. The EGM2008 global geopotential model has been used up to degree and order 360 in order to create gravity anomaly fields on both the sphere and the ellipsoid as the function fields of the current investigation. Harmonic analysis has then been carried out to compute the dimensionless potential coeficients using the created function fields. Three different harmonic analysis techniques have been applied: the least-squares technique, the Fast Fourier Transform (FFT) technique and the Gauss-Legendre numerical integration technique. The computed coeficients in spherical harmonics have then been compared with EGM2008 (in the frequency domain) and the computed fields on the sphere and the ellipsoid have been compared with fields created by EGM2008 up to degree and order 360 (in the space domain) in order to estimate the accuracy of the three different harmonic analysis techniques used within the current investigation. The results proved that the least-squares technique gives the best accuracy both in frequency and space domain. The FFT technique provides quite good results in a very short cpu time. The Gauss-Legendre technique gives the worst results among the presented techniques, but still the residuals in the space domain are negligibly small.

  11. Pairwise Harmonics for Shape Analysis Youyi Zheng, Chiew-Lan Tai, Eugene Zhang, Senior Member, IEEE, and Pengfei Xu

    E-print Network

    Tai, Chiew-Lan

    Pairwise Harmonics for Shape Analysis Youyi Zheng, Chiew-Lan Tai, Eugene Zhang, Senior Member, IEEE, and simultaneous surface segmentation and skeletonization. Index Terms--Shape analysis, pairwise harmonics, and Pengfei Xu Abstract--This paper introduces a simple yet effective shape analysis mechanism for geometry

  12. Harmonic Analysis: from Fourier to Haar Lecture Notes delivered at the Program for Women in

    E-print Network

    Pereyra, Cristina

    Harmonic Analysis: from Fourier to Haar Lecture Notes delivered at the Program for Women.1.1 Connection to complex analysis . . . . . . . . . . . . . . . . . . . . . 54 5.1.2 Connection to Fourier Ward y June 9, 2004 Contents 1 Introduction 1 2 Crash course on the Fourier transform on the line 3 2

  13. Experiment on Impulsive Excitation, Resonance, and Fourier Analysis of a Harmonic Oscillator.

    ERIC Educational Resources Information Center

    Macomber, Hilliard K.

    1981-01-01

    Describes an electric circuit permitting easy observation and measurement of the response of a damped harmonic oscillator to impulsive excitation. The impulse analysis is carried out and related to experimental observations. The phenomenon of resonance is then interpreted and demonstrated, and through it, contact is made with Fourier analysis

  14. Deepening the vector coherent state analysis: Revisiting the harmonic oscillator

    E-print Network

    I. Aremua; J. Ben Geloun; M. N. Hounkonnou

    2011-09-20

    Vector coherent states (VCS) viewed as a generalization of ordinary coherent states for higher rank tensor Hilbert spaces are investigated. We consider a systematic way of generating classes of VCS which are solvable (i.e., in the present context, normalizable states satisfying a resolution of the identity) on the Hilbert space of 2D and 3D harmonic oscillators. Thanks to the type of construction, these VCS are classified according to specific criteria. Furthermore, in many cases, the found classes of VCS are continuously deformable one onto another, still remaining solvable.

  15. Harmonic Map Analysis of SU(N) Gravitating Skyrmions

    E-print Network

    Y. Brihaye; B. Hartmann; T. Ioannidou; W. Zakrzewski

    2003-12-23

    In this paper the SU(N) Einstein-Skyrme system is considered. We express the chiral field (which is not a simple embedding of the SU(2) one) in terms of harmonic maps. In this way, SU(N) spherical symmetric equations can be obtained easily for any $N$ and the gravitating skyrmion solutions of these equations can be studied. In particular, the SU(3) case is considered in detail and three different types of gravitating skyrmions with topological charge 4, 2 and 0, respectively, are constructed numerically. Note that the configurations with topological charge 0 correspond to mixtures of skyrmions and antiskyrmions.

  16. Analysis and Design of New Harmonic Mitigation Approaches

    E-print Network

    Aeloiza Matus, Eddy 1972-

    2012-11-01

    is proposed to reduce the HF circulating current and a zero-sequence control loop to mitigate the low frequency circulating current is also proposed [56]-[58]. 5 Power Quality Standards 1.2. IEEE 519-1981 [67] 1.2.1 In 1981... to determine whether or not the new converters were going to be a problem. It was impractical and not economical to mitigate the harmonics for each non-linear load. Therefore, the IEEE 519-1981 was designed to help these users with the application...

  17. Data Analysis in Physics Examination

    ERIC Educational Resources Information Center

    Forster, Patricia A.

    2005-01-01

    This paper presents a critical analysis of data analysis requirements in physics tertiary entrance examinations. The setting is Western Australia. Common aspects of the questions asked over 14 years and changes in the questions since a major syllabus reform are identified. Similar changes in other jurisdictions are referenced. The data analysis…

  18. Distortion Analysis of GaAs MESFETs Based on Physical Model using PISCESHB

    E-print Network

    Dutton, Robert W.

    As MESFETs with low distortion characteristics are strongly demanded in multi­channel communication systemsDistortion Analysis of GaAs MESFETs Based on Physical Model using PISCES­HB Junko Sato simulations of GaAs MESFETs based on physical model and applying harmonic balance method have been

  19. Spherical harmonic analysis of a synoptic climatology generated with a global general circulation model

    NASA Technical Reports Server (NTRS)

    Christidis, Z. D.; Spar, J.

    1980-01-01

    Spherical harmonic analysis was used to analyze the observed climatological (C) fields of temperature at 850 mb, geopotential height at 500 mb, and sea level pressure. The spherical harmonic method was also applied to the corresponding "model climatological" fields (M) generated by a general circulation model, the "GISS climate model." The climate model was initialized with observed data for the first of December 1976 at 00. GMT and allowed to generate five years of meteorological history. Monthly means of the above fields for the five years were computed and subjected to spherical harmonic analysis. It was found from the comparison of the spectral components of both sets, M and C, that the climate model generated reasonable 500 mb geopotential heights. The model temperature field at 850 mb exhibited a generally correct structure. However, the meridional temperature gradient was overestimated and overheating of the continents was observed in summer.

  20. Analysis of astrometric catalogues with vector spherical harmonics

    E-print Network

    Francois Mignard; Sergei Klioner

    2012-09-17

    Comparison of stellar catalogues with position and proper motion components using a decomposition on a set of orthogonal vector spherical harmonics. We show the theoretical and practical advantages of this technique as a result of invariance properties and the independence of the decomposition from a prior model. We describe the mathematical principles used to perform the spectral decomposition, evaluate the level of significance of the multipolar components and examine the transformation properties under space rotation. The principles are illustrated with a characterisation of the systematic effects in the FK5 catalogue compared to Hipparcos and with an application to the extraction of the rotation and dipole acceleration in the astrometric solution of QSOs expected from Gaia.

  1. Harmonic analysis of the DTU10 global gravity anomalies

    NASA Astrophysics Data System (ADS)

    Abrykosov, O.; Förste, Ch.; Gruber, Ch.; Shako, R.; Barthelmes, F.

    2012-04-01

    We have computed the Earth's gravity models to degree/order 5400 and 10800 (in terms of the ellipsoidal and spherical harmonics) from a rigorous integration of the 2'x2' and 1'x1' global grids of gravity anomalies provided by the Danish Technical University (DTU). The gravity signal recovered from the DTU10 data shows 1) a strong dependency on the truncation of the EGM2008 gravity model which were used to fill-in land areas in the DTU10 grids and 2) an irregular behaviour at frequencies behind the resolution of the EGM2008. We discuss the gravity signal and its accuracy estimation computed from the complete DTU10 grids as well as separately from the data over land and ocean areas.

  2. ANALYSIS-BY-SYNTHESIS MULTIMODE HARMONIC SPEECH CODING AT 4 KB/S Chunyan Li and Vladimir Cuperman

    E-print Network

    California at Santa Barbara, University of

    ANALYSIS-BY-SYNTHESIS MULTIMODE HARMONIC SPEECH CODING AT 4 KB/S Chunyan Li and Vladimir Cuperman: [chunyan, vladimir]@laurel.ece.ucsb.edu ABSTRACT This paper presents a 4 kb/s Analysis-by-Synthesis Multimode Harmonic Coder (AbS-MHC). Novel features of this coder include a signal modification technique

  3. Mesh adaptation in finite element analysis of 2D steady state time harmonic eddy current problems

    Microsoft Academic Search

    P. Alotto; P. Girdinio; M. Nervi; P. Fernandes

    1996-01-01

    A local error estimation and adaptive meshing method developed by the authors for finite element analysis of 2D electrostatic and magnetostatic problems is now extended to 2D steady state time harmonic quasistatic eddy current problems. Local error estimation is based on the approximate solution of an independent differential problem in each triangular element. Mesh refinement is carried out by adding

  4. TENURE-TRACK ASSISTANT PROFESSOR POSITION in Mathematics with Specialty in Harmonic Analysis

    E-print Network

    Gallo, Linda C.

    mathematics. Applications should include: a cover letter, curriculum vita, a description of research programTENURE-TRACK ASSISTANT PROFESSOR POSITION in Mathematics with Specialty in Harmonic Analysis The Department of Mathematics and Statistics at San Diego State University invites applications for a position

  5. Harmonic analysis of climatological sea surface salinity Tim P. Boyer and Sydney Levitus

    E-print Network

    Harmonic analysis of climatological sea surface salinity Tim P. Boyer and Sydney Levitus Ocean decomposition of the World Ocean Atlas 1998 (WOA98) fields of climatological monthly mean salinity is used salinity scale (PSS). Areas with an annual cycle larger than 0.3 include the northern Indian Ocean

  6. The algorithm of interpolating windowed FFT for harmonic analysis of electric power system

    Microsoft Academic Search

    Fusheng Zhang; Zhongxing Geng; Wei Yuan

    2001-01-01

    The fast Fourier transform (FFT) cannot be directly used in the harmonic analysis of an electric power system because of its higher errors, especially the phase error. This paper discusses the leakage phenomenon of FFT and presents a new amending algorithm, poly-item cosine window interpolation, which is based on the interpolating algorithm proposed by V. Jain and T Grandke. This

  7. Explicit thermostatics of certain classical one-dimensional lattice models by harmonic analysis

    E-print Network

    Georg Junker

    1994-03-28

    A certain class of one-dimensional classical lattice models is considered. Using the method of abstract harmonic analysis explicit thermostatic properties of such models are derived. In particular, we discuss the low-temperature behavior of some of these models.

  8. An affine-invariant inequality for rational functions and applications in harmonic analysis

    Microsoft Academic Search

    Spyridon Dendrinos; Magali Folch-Gabayet; James Wright

    2010-01-01

    We extend an ane invariant inequality for vector polynomials established in (6) to general rational functions. As a consequence we obtain sharp universal estimates for various problems in euclidean harmonic analysis dened with respect to the so-called ane arclength measure.

  9. Operational modal analysis in the presence of harmonic excitations by the use of transmissibility measurements

    Microsoft Academic Search

    Christof Devriendt; Gert De Sitter; Steve Vanlanduit; Patrick Guillaume

    2009-01-01

    Operational modal analysis (OMA) is based on the assumption that the forces on the structure are the result of a stochastic process, so being white noise. In practice, however, structural vibrations observed in operation cannot always be considered as pure white-noise excitation. In many mechanical structures the loading forces are often more complex and even harmonic components can be present

  10. The development and analysis of geopotential coefficient models to spherical harmonic degree 360

    NASA Technical Reports Server (NTRS)

    Rapp, Richard H.; Pavlis, Nikolaos K.

    1990-01-01

    Two new geopotential coefficient models to spherical harmonic degree 360 are developed using recent advances made in theoretical modeling methods, satellite gravitational models, and expanded and improved terrestrial data. The new models are based on the combination of a satellite potential coefficient model (GEM-T2) to degree 50 with 30-arc mean gravity anomalies, yielding an adjusted set of coefficients and gravity anomalies, which were then harmonically analyzed to yield a set of potential coefficients to degree 360. The models were verified in several ways including satellite orbit residual analysis, demonstrating a substantial improvement over previous high-degree expansions.

  11. Full vector spherical harmonic analysis of the Holocene geomagnetic field

    NASA Astrophysics Data System (ADS)

    Richardson, Marcia

    High-quality time-series paleomagnetic measurements have been used to derive spherical harmonic models of Earth's magnetic field for the past 2,000 years. A newly-developed data compilation, PSVMOD2.0 consists of time-series directional and intensity records that significantly improve the data quality and global distribution used to develop previous spherical harmonic models. PSVMOD2.0 consists of 185 paleomagnetic time series records from 85 global sites, including 30 full-vector records (inclination, declination and intensity). It includes data from additional sites in the Southern Hemisphere and Arctic and includes globally distributed sediment relative paleointensity records, significantly improving global coverage over previous models. PSVMOD2.0 records have been assessed in a series of 7 regional intercomparison studies, four in the Northern Hemisphere and 3 in the southern hemisphere. Comparisons on a regional basis have improved the quality and chronology of the data and allowed investigation of spatial coherence and the scale length associated with paleomagnetic secular variation (PSV) features. We have developed a modeling methodology based on nonlinear inversion of the PSVMOD2.0 directional and intensity records. Models of the geomagnetic field in 100-year snapshots have been derived for the past 2,000 with the ultimate goal of developing models spanning the past 8,000 years. We validate the models and the methodology by comparing with the GUFM1 historical models during the 400-year period of overlap. We find that the spatial distribution of sites and quality of data are sufficient to derive models that agree with GUFM1 in the large-scale characteristics of the field. We use the the models derived in this study to downward continue the field to the core-mantle boundary and examine characteristics of the large-scale structure of the magnetic field at the source region. The derived models are temporally consistent from one epoch to the next and exhibit many of the expected characteristics of the field over time (high-latitude flux lobes, South Atlantic reverse flux patch, north pole reverse or null flux region).

  12. Full sky harmonic analysis hints at large UHECR deflections

    E-print Network

    Tinyakov, P G

    2014-01-01

    The full-sky multipole coefficients of the ultra-high energy cosmic ray (UHECR) flux have been measured for the first time by the Pierre Auger and Telescope Array collaborations using a joint data set with E > 10 EeV. We calculate these harmonic coefficients in the model where UHECR are protons and sources trace the local matter distribution, and compare our results with observations. We find that the expected power for low multipoles (dipole and quadrupole, in particular) is sytematically higher than in the data: the observed flux is too isotropic. We then investigate to which degree our predictions are influenced by UHECR deflections in the regular Galactic magnetic field (GMF). It turns out that the UHECR power spectrum coefficients $C_\\ell$ are quite insensitive to the effects of the GMF, so it is unlikely that the discordance can be reconciled by tuning the GMF model. On the contrary, a sizeable fraction of uniformly distributed flux (representing for instance an admixture of heavy nuclei with considerab...

  13. Harmonic Analysis of Noninvasively Recorded Arterial Pressure Waveforms in Healthy Bonnet Macaques (Macaca radiata)

    PubMed Central

    Olafiranye, Oladipupo; Salciccioli, Louis; Kamran, Haroon; Stewart, Mark; Carter, John; Lazar, Jason M

    2011-01-01

    To characterize primate arterial waveforms, we prospectively studied 38 bonnet macaques (Macaca radiata; 25 female, 13 ± 4 y). Brachial artery waveforms were recorded from these animals by applanation tonometry and were decomposed into harmonics by using Fourier analysis. The ratio of individual to total harmonic amplitude (H:T) was derived from frequency spectra. Left ventricular (LV) mass, ejection fraction, fractional shortening, septal wall thickness, posterior wall thickness, LV end-diastolic diameter, and LV end-systolic diameter were obtained by echocardiography in all 38 monkeys. Blood pressure was obtained by sphygmomanometry. The fundamental frequency was 2.76 cycles/s. Harmonics ranged from 5 to 14. Indexed LV mass was inversely correlated with third H:T and second H:T but not with systolic or diastolic blood pressure. In addition, the third H:T was inversely correlated with septal wall thickness, posterior wall thickness, and LV end-diastolic diameter, whereas second H:T was inversely correlated with LV end-diastolic diameter. Heart rate was inversely correlated with eighth H:T. On multivariate analysis adjusting for age, gender, weight, and length, only third H:T was an independent predictor of LV mass. Harmonic analysis of arterial waveforms may provide information pertaining to LV mass. Lower H:T ratios (second and third) are related to LV mass, whereas higher H:T (eighth) is related to heart rate. PMID:21333168

  14. Platonic polyhedra tune the 3-sphere: III. Harmonic analysis on octahedral spherical 3-manifolds

    E-print Network

    Peter Kramer

    2009-10-13

    From the homotopy groups of three distinct octahedral spherical 3-manifolds we construct the isomorphic groups H of deck transformations acting on the 3-sphere. The H-invariant polynomials on the 3-sphere constructed by representation theory span the bases for the harmonic analysis on three spherical manifolds. Analysis of the Cosmic Microwave Background in terms of these new bases can reveal a non-simple topology of the space part of space-time.

  15. Analysis of crystallographic texture information by the hyperspherical harmonic expansion

    E-print Network

    Mason, Jeremy K. (Jeremy Kyle)

    2009-01-01

    The field of texture analysis is fundamentally concerned with measuring and analyzing the distribution of crystalline orientations in a given polycrystalline material. Traditionally, the orientation distribution function ...

  16. Design and implementation of a modified Fourier analysis harmonic current computation technique for power active filters using DSPs

    Microsoft Academic Search

    M. El-Habrouk; M. K. Darwish

    2001-01-01

    The design and implementation of a harmonic current computation technique based on a modified Fourier analysis, suitable for active power fdters incorporating DSPs is presented. The proposed technique is suitable for monitoring and control of load current harmonics for real-time applications. The derivation of the basic equations based on the proposed technique and the system implementation using the Analogue Devices

  17. SPEECH ENHANCEMENT IN CAR NOISE ENVIRONMENT BASED ON AN ANALYSIS-SYNTHESIS APPROACH USING HARMONIC NOISE MODEL

    E-print Network

    So, Hing-Cheung

    SPEECH ENHANCEMENT IN CAR NOISE ENVIRONMENT BASED ON AN ANALYSIS- SYNTHESIS APPROACH USING HARMONIC using harmonic noise model (HNM) in car noise environment. The major advantages of this method are effective suppression of car noise even in very low signal-to-noise ratio environments and mitigation

  18. Optimization of high-order harmonic generation by genetic algorithm and wavelet time-frequency analysis of quantum dipole emission

    E-print Network

    Chu, Shih-I

    Optimization of high-order harmonic generation by genetic algorithm and wavelet time-frequency analysis of quantum dipole emission Xi Chu and Shih-I Chu Department of Chemistry, University of Kansas-dimensional quantum study of the coherent control of high-order harmonic generation HHG processes in intense pulsed

  19. Three-dimensional analysis of collective relativistic electron motion and coherent harmonic generation driven by an intense pulsed Gaussian beam

    E-print Network

    Three-dimensional analysis of collective relativistic electron motion and coherent harmonic current density is the coher- ent relativistic harmonic generation. The motion of individual electrons electron motion driven by intense laser pulses can become highly nonlinear as results of the v B term

  20. Loss Analysis of IPM Motors Considering Carrier Harmonics

    Microsoft Academic Search

    Katsumi Yamazaki; Atsushi Abe

    2007-01-01

    In this paper, we investigate losses of interior permanent magnet motors driven by PWM inverters using 3-D finite element analysis, which can estimate the eddy current loss in the permanent magnet accurately. The calculated losses are compared with the measured results and the theoretical solution to verify the validity of the analysis. The method to decompose the electromagnetic field distribution

  1. Cognitive task analysis: harmonizing tasks to human capacities

    Microsoft Academic Search

    MARK A. NEERINCX; EDWIN GRIFFIOEN

    1996-01-01

    This paper presents the development of a cognitive task analysis that assesses the task load of jobs and provides indicators for the redesign of jobs. General principles of human task performance were selected and, subsequently, integrated into current task modelling techniques. The resulting cognitive task analysis centres around four aspects of task load: the number of actions in a period,

  2. Enhancing tidal harmonic analysis: Robust (hybrid L1/L2) solutions

    NASA Astrophysics Data System (ADS)

    Leffler, Keith E.; Jay, David A.

    2009-01-01

    Traditional harmonic analysis of tides is highly sensitive to omnipresent environmental noise. Robust fitting is an extension of the ordinary least squares calculation of harmonic analysis that is more resistant to broad spectrum noise. Since the variance of the amplitude and phase is calculated from the power spectrum of the residual, a calculation that filters broad spectrum noise and reduces the residual variance will increase the confidence of the computed parameters, and also allows more low-amplitude constituents to be resolved from the background noise. Improvement in confidence and resolution of more constituents has obvious benefits to the resolution of both seasonal and long-term variation of amplitude and phase of tidal constituents. Using a 6 month calculation window, confidence intervals were systematically reduced by 30-85% over results calculated with standard methods, with an increase in resolved constituents of 20-75%. The analysis was carried out with Matlab, using the t-tide package [Pawlowicz, R., Beardsley, B., Lentz, S., 2002. Classical tidal harmonic analysis with errors in matlab using t-tide. Computers and Geosciences 28, 929-937], with modifications to accommodate Matlab's implementation of the Iteratively Reweighted Least Squares algorithm.

  3. Operational modal analysis in the presence of harmonic excitations by the use of transmissibility measurements

    NASA Astrophysics Data System (ADS)

    Devriendt, Christof; De Sitter, Gert; Vanlanduit, Steve; Guillaume, Patrick

    2009-04-01

    Operational modal analysis (OMA) is based on the assumption that the forces on the structure are the result of a stochastic process, so being white noise. In practice, however, structural vibrations observed in operation cannot always be considered as pure white-noise excitation. In many mechanical structures the loading forces are often more complex and even harmonic components can be present in the response. This is especially true, when measuring on mechanical structures containing rotating parts (e.g. cars, turbines, windmills), but also civil engineering structures may have responses superimposed by harmonic components. OMA procedures are, strictly speaking, not applicable in these situations. Current techniques may encounter difficulties to correctly identify the modal parameters, especially for modes with eigenfrequencies close to the harmonic frequencies. In this paper a recently proposed OMA technique based on transmissibility measurements will be applied. This method reduces the risk to wrongly identify the modal parameters due to the presence of harmonics. The unknown operational forces can be arbitrary (coloured noise, swept sine, impact, etc.) as long as they are persistently exciting in the frequency band of interest.

  4. A harmonic analysis method for unsteady transonic flow and its application to the flutter of airfoils

    NASA Technical Reports Server (NTRS)

    Ehlers, F. E.; Weatherill, W. H.

    1982-01-01

    A finite difference method for solving the unsteady transonic flow about harmonically oscillating wings is investigated. The procedure is based on separating the velocity potential into steady and unsteady parts and linearizing the resulting unsteady differential equation for small disturbances. The differential equation for the unsteady velocity potential is linear with spatially varying coefficients and with the time variable eliminated by assuming harmonic motion. A study is presented of the shock motion associated with an oscillating airfoil and its representation by the harmonic procedure. The effects of the shock motion and the resulting pressure pulse are shown to be included in the harmonic pressure distributions and the corresponding generalized forces. Analytical and experimental pressure distributions for the NACA 64A010 airfoil are compared for Mach numbers of 0.75, 0.80 and 0.842. A typical section, two-degree-of-freedom flutter analysis of a NACA 64A010 airfoil is performed. The results show a sharp transonic bucket in one case and abrupt changes in instability modes.

  5. Modeling and analysis of aircraft non-linear components for harmonics analysis

    SciTech Connect

    Karimi, K.J. [Boeing Computer Services, Seattle, WA (United States); Voss, J. [Boeing Commercial Airplane Group, Seattle, WA (United States)

    1995-12-31

    Modern commercial aircraft Electric Power Systems (EPS) include many nonlinear components which produce harmonics. The addition of all the current harmonics could result in a power system with unacceptable levels of voltage distortion. It is important to be able to predict the levels of voltage distortion at early program stages to correct any potential problems and avoid costly redesigns. In this paper the nature and sources of harmonic producing equipment are described. These sources of harmonics and their effect on aircraft power system operation are described. Models for various aircraft non-linear components are developed in this paper. These component models are used in a model of the Boeing 777 EPS which is used to calculate voltage harmonics for various airplane configurations and flight conditions. A description of this model and the models used for various components are given. Tests performed to validate these models are described. Comparison of experimental results with analytical model predictions are given.

  6. Analysis Of Harmonic And Transient Concerns For PWM Adjustable Speed Drives Using The Electromagnetic Transients Program

    Microsoft Academic Search

    Thomas E. Grebe; Le Tang

    1992-01-01

    This paper describes the development of a three-phase pulse-width modulation (PWM) adjustable-speed drive (ASD) model foruse~~iththeElectromagneticTransients Program (Em). In addition, several harmonic and transient concerns associated with drive operation are investigated. The characteristics of the drive system are determined for a base case condition and verified with theoretical quantities and field measurements. Drive parameters are analyxd using sensitivity analysis and

  7. Application of the homotopy analysis method for the Gross—Pitaevskii equation with a harmonic trap

    NASA Astrophysics Data System (ADS)

    Shi, Yu-Ren; Liu, Cong-Bo; Wang, Guang-Hui; Zhou, Zhi-Gang

    2012-12-01

    The Homotopy analysis method (HAM) is adopted to find the approximate analytical solutions of the Gross—Pitaevskii equation, a nonlinear Schrödinger equation is used in simulation of Bose—Einstein condensates trapped in a harmonic potential. Comparisons between the analytical solutions and the numerical solutions have been made. The results indicate that they fit very well with each other when the atomic interaction is weak.

  8. Error and Symmetry Analysis of Misner's Algorithm for Spherical Harmonic Decomposition on a Cubic Grid

    NASA Technical Reports Server (NTRS)

    Fiske, David R.

    2004-01-01

    In an earlier paper, Misner (2004, Class. Quant. Grav., 21, S243) presented a novel algorithm for computing the spherical harmonic components of data represented on a cubic grid. I extend Misner s original analysis by making detailed error estimates of the numerical errors accrued by the algorithm, by using symmetry arguments to suggest a more efficient implementation scheme, and by explaining how the algorithm can be applied efficiently on data with explicit reflection symmetries.

  9. High-order harmonic generation by chirped and self-guided femtosecond laser pulses. II. Time-frequency analysis

    SciTech Connect

    Tosa, V. [Department of Physics, KAIST, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); National Institute for R and D of Isotopic and Molecular Technologies, Cluj-Napoca (Romania); Kim, H.T.; Kim, I.J.; Nam, C.H. [Department of Physics, KAIST, Yuseong-gu, Daejeon, 305-701(Korea, Republic of)

    2005-06-15

    We present a time-dependent analysis of high-order harmonics generated by a self-guided femtosecond laser pulse propagating through a long gas jet. A three-dimensional model is used to calculate the harmonic fields generated by laser pulses, which only differ by the sign of their initial chirp. The time-frequency distributions of the single-atom dipole and harmonic field reveal the dynamics of harmonic generation in the cutoff. A time-dependent phase-matching calculation was performed, taking into account the self-phase modulation of the laser field. Good phase matching holds for only few optical cycles, being dependent on the electron trajectory. When the cutoff trajectory is phase matched, emitted harmonics are locked in phase and the emission intensity is maximized.

  10. Harmonic Analysis of Sedimentary Cyclic Sequences in Kansas, Midcontinent, USA

    USGS Publications Warehouse

    Merriam, D.F.; Robinson, J.E.

    1997-01-01

    Several stratigraphic sequences in the Upper Carboniferous (Pennsylvanian) in Kansas (Midcontinent, USA) were analyzed quantitatively for periodic repetitions. The sequences were coded by lithologic type into strings of datasets. The strings then were analyzed by an adaptation of a one-dimensional Fourier transform analysis and examined for evidence of periodicity. The method was tested using different states in coding to determine the robustness of the method and data. The most persistent response is in multiples of 8-10 ft (2.5-3.0 m) and probably is dependent on the depositional thickness of the original lithologic units. Other cyclicities occurred in multiples of the basic frequency of 8-10 with persistent ones at 22 and 30 feet (6.5-9.0 m) and large ones at 80 and 160 feet (25-50 m). These levels of thickness relate well to the basic cyclothem and megacyclothem as measured on outcrop. We propose that this approach is a suitable one for analyzing cyclic events in the stratigraphic record.

  11. Reconstruction of the land surface temperature time series using harmonic analysis

    NASA Astrophysics Data System (ADS)

    Xu, Yongming; Shen, Yan

    2013-12-01

    Satellite remote sensing is an important approach for obtaining land surface temperature (LST) over wide temporal and spatial ranges. However, the presence of clouds generates numerous missing and abnormal values that affect the application of LST data. To fill data gaps and improve data quality, the Harmonic ANalysis of Time Series (HANTS) algorithm was employed to remove cloud-affected observations and reconstruct the Moderate Resolution Imaging Spectroradiometer (MODIS) LST data taken in the year 2005 for the Yangtze River Delta region of China. Analysis of MODIS data quality indicated that the yearly proportion of high-quality LST data in this region was less than 50% with numerous missing and low-quality data points. To reconstruct 8-day LST via the removal of cloud-contaminated observations, we applied pixel-by-pixel harmonic fitting to the time series and used fitted values to replace the missing and abnormal values in the original LST data. To evaluate the reconstruction performance, a simulated dataset was generated according to the percentage of cloud coverage in each 8-day period. Satisfactory validation results indicate that the harmonic method can effectively fit the NA Values caused by cloud cover and fill data gaps in the LST data, which can significantly improve the practical value of the MODIS LST dataset.

  12. High-order harmonic generation by chirped and self-guided femtosecond laser pulses. I. Spatial and spectral analysis

    SciTech Connect

    Tosa, V.; Kim, H.T.; Kim, I.J.; Nam, C.H. [Department of Physics, KAIST, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2005-06-15

    For the analysis of high-order harmonics generated in a long gas jet by intense chirped femtosecond laser pulses, calculations of the laser propagation and harmonic generation were performed in terms of a nonadiabatic three-dimensional model. The self-guided propagation, observed at the conditions of bright harmonic generation, was confirmed by the model calculations. When using negatively chirped pulses, the calculated distribution of the harmonic field is spatially and spectrally confined, being generated on axis with a narrow spectral profile. The positively chirped pulses generate broad spectral distribution on axis, and narrow off axis, but in the latter case with a large emission angle. The estimation of harmonic beam divergence agreed well with experimentally measured data, showing the lowest divergence at the conditions of the brightest harmonic generation. Spectral, temporal, and spatial modifications of the propagated laser pulse are found to influence decisively the single-atom response and ultimately the harmonic field, providing a coherent picture of harmonic generation.

  13. The harmonic power spectrum of the soft X-ray background I. The data analysis

    E-print Network

    W. Sliwa; A. M. Soltan; M. J. Freyberg

    2001-10-22

    Fluctuations of the soft X-ray background are investigated using harmonic analysis. A section of the ROSAT All-Sky Survey around the north galactic pole is used. The flux distribution is expanded into a set of harmonic functions and the power spectrum is determined. Several subsamples of the RASS have been used and the spectra for different regions and energies are presented. The effects of the data binning in pixels are assessed and taken into account. The spectra of the analyzed samples reflect both small scale effects generated by strong discrete sources and the large scale gradients of the XRB distribution. Our results show that the power spectrum technique can be effectively used to investigate anisotropy of the XRB at various scales. This statistics will become a useful tool in the investigation of various XRB components.

  14. Entropy and complexity analysis of the D-dimensional rigid rotator and hyperspherical harmonics

    E-print Network

    J. S. Dehesa; A. Guerrero; P. Sánchez-Moreno

    2015-03-17

    In this paper we carry out an information-theoretic analysis of the $D$-dimensional rigid rotator by studying the entropy and complexity measures of its wavefunctions, which are controlled by the hyperspherical harmonics. These measures quantify single and two-fold facets of the rich intrinsic structure of the system which are manifest by the intricate and complex variety of D-dimensional geometries of the hyperspherical harmonics. We calculate the explicit expressions of the entropic moments and the R\\'enyi entropies as well as the Fisher-R\\'enyi, Fisher-Shannon and LMC complexities of the system. The explicit expression for the last two complexity measures is not yet possible, mainly because the logarithmic functional of the Shannon entropy has not yet been obtained up until now in a closed for

  15. Regional GPS-based ionospheric TEC model over Australia using Spherical Cap Harmonic Analysis

    NASA Astrophysics Data System (ADS)

    Bouya, Zahra; Terkildsen, Michael; Neudegg, Dave

    This paper proposes an approach to regional Total Electron Content (TEC) representation using Spherical Cap Harmonic Analysis (SCHA) [Haines,1988] which, when applied to the whole sphere, is the usual method referred to as ordinary Spherical Harmonic Analysis (SHA). The model is based on longitudinal expansion in Fourier series and fractional Legendre colatitudinal functions over a spherical cap-like region including the Australian continent. The SCHA has been applied to values of the ionospheric TEC parameter as observed by the Australian Regional GPS Network (ARGN). This harmonic expansion requires less coefficients to represent the fine structure of regional ionospheric features than global SHA. Slant TEC values along the GPS signal path from the ARGN GPS receivers are converted to vertical TEC. The SCHA coefficients are estimated from the vertical TEC at the Ionospheric Pierce Points (IPPs). TEC maps were interpolated on a 2x0.5 longitude/latitude grid using the estimated spherical harmonic coefficients. The TEC maps produced over the region are promising and reveal a marginally small rms error. It has been found that for the regional modeling of TEC over the Australian continent, the model well represents basic ionospheric features in the sample space and behaves reasonably within regions where no experimental data are available. The obtained results confirm the usefulness of SCHA for near real time regional TEC mapping and the potential for its application to the modeling of other ionospheric parameters. Also, the SCHA parameters may be adapted to take advantage of regions of densely distributed observations in order to observe and model ionospheric dynamics over Australia on a range of spatial scales, as well as investigate TEC variations under quiet and disturbed ionospheric conditions. KEYWORDS: SCHA, TEC, GPS, IONOSPHERE, AUSTRALIA

  16. Random harmonic analysis program, L221 (TEV156). Volume 2: Supplemental system design and maintenenace document

    NASA Technical Reports Server (NTRS)

    Graham, M. L.; Clemmons, R. E.; Miller, R. D.

    1979-01-01

    Volume 2 of a two volume document is presented. A computer program, L222 (TEV 156), available for execution on the CDC 6600 computer is described. The program is capable of calculating steady-state solutions for linear second-order differential equations due to sinusoidal forcing functions. From this, steady-state solutions, generalized coordinates, and load frequency responses may be determined. Statistical characteristics of loads for the forcing function spectral shape may also be calculated using random harmonic analysis techniques. The particular field of application of the program is the analysis of airplane response and loads due to continuous random air turbulence.

  17. The Influence of Spring Length on the Physical Parameters of Simple Harmonic Motion

    ERIC Educational Resources Information Center

    Triana, C. A.; Fajardo, F.

    2012-01-01

    The aim of this work is to analyse the influence of spring length on the simple harmonic motion of a spring-mass system. In particular, we study the effect of changing the spring length on the elastic constant "[kappa]", the angular frequency "[omega]" and the damping factor "[gamma]" of the oscillations. To characterize the behaviour of these…

  18. VII Hotine-Marussi Symposium on Theoretical Geodesy, 6-10 July 2009, Rome, Italy. Performance analysis of isotropic spherical harmonic spectral windows

    E-print Network

    Stuttgart, Universität

    analysis of isotropic spherical harmonic spectral windows B. Devaraju and N. Sneeuw Institute of Geodesy isotropic spherical harmonic spectral windows in the spa- tial domain. The parameters are devised in order to answer the following question: If an isotropic spherical harmonic window is applied in the spectral

  19. Inter-annual variation of NDVI over Korea Peninsula using harmonic analysis

    NASA Astrophysics Data System (ADS)

    Kim, In-hwan; Han, Kyung-Soo; Pi, Kyoung-Jin; Park, Soo-Jae; Kim, Sang-Il

    2010-10-01

    Global warming and climatic changes due to human activities impact on marine and terrestrial ecosystems, which feedbacks to climate system. These negative feedbacks amplify or accelerate again global climate change. In particular, life cycle of vegetation sensitively vary according to global climate change. This study attempts to analyze quantitatively vegetation change in Korea peninsula using harmonic analysis. Satellite data was extracted from SPOT/VEGETATION S10 MVC (Maximum Value Composite) NDVI (Normalized Difference Vegetation Index) products during 10 years (1999 to 2008) around Korea peninsula. This NDVI data set was pre-processed to correct noise pixels cause by cloud and ground wetness. Variation of vegetation life cycle was analyzed through amplitudes and phases of annual harmonic components (first harmonic components) per year for two land cover types (cropland and forest). The results clearly show that the peak of vegetation life cycle in Korea peninsula is brought forward to early. Especially, it represents that the phases over low latitudes area between 32.8°N and 38°N steadily decrease every year both forest and cropland. The study estimated that phase values moved up approximately 0.5 day per year in cropland and 0.8 day per year in forest.

  20. Analysis of binning of normals for spherical harmonic cross-correlation

    NASA Astrophysics Data System (ADS)

    Larkins, Robert L.; Cree, Michael J.; Dorrington, Adrian A.

    2012-03-01

    Spherical harmonic cross-correlation is a robust registration technique that uses the normals of two overlapping point clouds to bring them into coarse rotational alignment. This registration technique however has a high computational cost as spherical harmonics need to be calculated for every normal. By binning the normals, the computational efficiency is improved as the spherical harmonics can be pre-computed and cached at each bin location. In this paper we evaluate the efficiency and accuracy of the equiangle grid, icosahedron subdivision and the Fibonacci spiral, an approach we propose. It is found that the equiangle grid has the best efficiency as it can perform direct binning, followed by the Fibonacci spiral and then the icosahedron, all of which decrease the computational cost compared to no binning. The Fibonacci spiral produces the highest achieved accuracy of the three approaches while maintaining a low number of bins. The number of bins allowed by the equiangle grid and icosahedron are much more restrictive than the Fibonacci spiral. The performed analysis shows that the Fibonacci spiral can perform as well as the original cross-correlation algorithm without binning, while also providing a significant improvement in computational efficiency.

  1. Experiment Design and Analysis Guide - Neutronics & Physics

    SciTech Connect

    Misti A Lillo

    2014-06-01

    The purpose of this guide is to provide a consistent, standardized approach to performing neutronics/physics analysis for experiments inserted into the Advanced Test Reactor (ATR). This document provides neutronics/physics analysis guidance to support experiment design and analysis needs for experiments irradiated in the ATR. This guide addresses neutronics/physics analysis in support of experiment design, experiment safety, and experiment program objectives and goals. The intent of this guide is to provide a standardized approach for performing typical neutronics/physics analyses. Deviation from this guide is allowed provided that neutronics/physics analysis details are properly documented in an analysis report.

  2. Analysis and design of optical guided-wave devices for quasi-phasematched second harmonic generation and Bragg deflection

    Microsoft Academic Search

    Nandakumar Ramanujam

    1997-01-01

    Integrated optics-based approaches to beam steering, beam shaping, beam collimation, and quasi-phasematched (QPM) second harmonic generation (SHG) of light offer significant advantages over conventional approaches based on bulk optics. The research in this dissertation addresses the analysis and design of optical guided-wave devices for both efficient quasi-phasematched second harmonic generation in diffused channel waveguides, as well as Bragg deflection of

  3. Numerical Evaluation by Harmonic Analysis of the (Epsilon)-Function of the Theodorsen Arbitrary-Airfoil Potential Theory

    NASA Technical Reports Server (NTRS)

    Naiman, Irven

    1945-01-01

    Finite trigonometric series is fitted by harmonic analysis as an approximation function to the psi function of the Theodorsen arbitrary-airfoil potential theory. By harmonic synthesis, the corresponding conjugate trigonometric series is used as an approximation to the epsilon function. A set of coefficients of particularly simple form is obtained algebraically for direct calculation of the epsilon values from the corresponding set of psi values. Complete derivation of this process is presented.

  4. Investigations of Low and Moderate Harmonic Fast Wave Physics on CDX-U

    SciTech Connect

    J. Spaleta; R. Majeski; C.K. Phillips; R.J. Dumont; R. Kaita; V. Soukhanovskii; L. Zakharov

    2003-07-14

    Third harmonic hydrogen cyclotron fast wave heating studies are planned in the near term on CDX-U to investigate the potential for bulk ion heating. In preparation for these studies, the available radio-frequency power in CDX-U has been increased to 0.5 MW. The operating frequency of the CDX-U radio-frequency transmitter was lowered to operate in the range of 8-10 MHz, providing access to the ion harmonic range 2* {approx} 4* in hydrogen. A similar regime is accessible for the 30 MHz radio-frequency system on the National Spherical Torus Experiment (NSTX), at 0.6 Tesla in hydrogen. Preliminary computational studies over the plasma regimes of interest for NSTX and CDX-U indicate the possibility of strong localized absorption on bulk ion species.

  5. Boston University Physics Easy Java Simulation: Uniform Circular Motion and Simple Harmonic Motion

    NSDL National Science Digital Library

    2009-09-02

    This interactive simulation offers a way for students to explore the connection between uniform circular motion and simple harmonic motion. The display shows two blocks on springs oscillating horizontally, and two balls traveling in uniform motion in a circular path. The user sets initial values for the blocks: amplitude, mass, and spring constant. The two balls are automatically set to the same values. Students are able to see that the circular motion of each ball corresponds to the motion of the blocks, thus promoting understanding of the basic equation for objects undergoing simple harmonic motion. To extend the learning, users can set values for the phase angles of each block. Also included by the author is a set of suggested activities to accompany the simulation. See Related Materials for an extensive online multimedia tutorial from PhysClips on the topic of simple harmonic motion. This applet was created with EJS, Easy Java Simulations, a modeling tool that allows users without formal programming experience to generate computer models and simulations.

  6. Application of abstract harmonic analysis to the high-speed recognition of images

    NASA Technical Reports Server (NTRS)

    Usikov, D. A.

    1979-01-01

    Methods are constructed for rapidly computing correlation functions using the theory of abstract harmonic analysis. The theory developed includes as a particular case the familiar Fourier transform method for a correlation function which makes it possible to find images which are independent of their translation in the plane. Two examples of the application of the general theory described are the search for images, independent of their rotation and scale, and the search for images which are independent of their translations and rotations in the plane.

  7. Harmonic Analysis and Free Field Realization of the Takiff supergroup of GL(1|1)

    E-print Network

    Babichenko, Andrei

    2014-01-01

    Takiff superalgebras are a family of non semi-simple Lie superalgebras that are believed to give rise to a rich structure of indecomposable representations of associated conformal field theories. We consider the Takiff superalgebra of gl(1|1), especially we perform harmonic analysis for the corresponding supergroup. We find that every simple module appearing is part of an infinite-dimensional indecomposable but reducible module. We lift our results to two free field realizations for the corresponding conformal field theory and construct some modules.

  8. Harmonic Analysis and Free Field Realization of the Takiff supergroup of GL(1|1)

    E-print Network

    Andrei Babichenko; Thomas Creutzig

    2015-05-28

    Takiff superalgebras are a family of non semi-simple Lie superalgebras that are believed to give rise to a rich structure of indecomposable representations of associated conformal field theories. We consider the Takiff superalgebra of gl(1|1), especially we perform harmonic analysis for the corresponding supergroup. We find that every simple module appearing is part of an infinite-dimensional indecomposable but reducible module. We lift our results to two free field realizations for the corresponding conformal field theory and construct some modules.

  9. Non-harmonic analysis for high-resolution optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chong, Changho; Cao, Xu; Morosawa, Atsushi; Totsuka, Koki; Suzuki, Takuya; Hirobayashi, Shigeki

    2010-02-01

    A novel processing technique called Non-Harmonic Analysis (NHA) is proposed for high-resolution OCT imaging. Conventional Fourier-Domain OCT relies on the FFT calculation which depends on the window function and length. NHA can resolve high frequency without being influenced by window function or frame length of sampled data. The results show that NHA process realizes practical image resolution equivalent to 100nm swept range by using significantly reduced wavelength range, and also implies the potential of high resolution imaging capability without the need of a broadband source.

  10. Three-dimensional analysis of harmonic generation in self-amplified spontaneous emission.

    SciTech Connect

    Huang, Z.; Kim, K.-J.

    1999-09-01

    In a high-gain free-electron laser, strong bunching at the fundamental wavelength can drive substantial harmonic bunching and sizable power levels at the harmonic frequencies. In this paper, we investigate the three-dimensional evolution of the harmonic fields based on the coupled Maxwell-Vlasov equations that take into account the nonlinear harmonic interaction. Each harmonic field is the sum of a self-amplified term and a term driven by the nonlinear harmonic interaction. In the exponential gain regime, the growth rate of the dominant nonlinear term is much faster than that of the self-amplified harmonic field. As a result, the gain length and the transverse profile of the first few harmonics are completely determined by those of the fundamental. A percentage of the fundamental power level is found at the third harmonic frequency right before saturation for the current self-amplified spontaneous emission projects.

  11. A Comparison of Spherical Harmonics and Slepian Basis Functions in Magnetic Field Analysis

    NASA Astrophysics Data System (ADS)

    Boxham, J.; Sterenborg, M. G.

    2008-12-01

    Planetary probes often have equatorial, low inclination, orbits around the planet in question, leaving polar data gaps. For example, the orbital path of the Cassini probe around Saturn is essentially limited to a narrow latitudinal band around the equator. For potential field studies this can lead to problems as such studies traditionally employ spherical harmonics, which require global support, to describe the potential field (Simons 2006, Simons 2006a, Wieczorek 2005). Here we consider the use of different basis functions that have been specifically designed to deal with such situations. In contrast to using spherical harmonics for a spectral representation of such 'equatorial' data, an approach which can be prone to errors because global support is required to achieve orthogonality over the whole sphere, Slepian functions, which are orthogonal over both the whole sphere and the region of data coverage, and which have their energy optimally concentrated in the spatial and spectral domain, should yield better results. We have set out to compare the use of these new basis functions in magnetic field analysis with the canonical spherical harmonics. Are the Slepian basis functions better for resolving the magnetic field? Such comparisons have been done in the past, (Simons 2006, Simons 2006a) but took a more theoretical stance, evaluating only a bandlimited white noise source field. We are more interested in the performance under practical circumstances. We employ a number of criteria to evaluate the performance of both basis functions such as: errors, variances, spectral leakage. We have used an Earth magnetic field model, POMME, to generate realistic magnetic field values and Cassini's trajectory scaled to Earth to generate typical equatorial coverage. Simons, F., Dahlen, F., 2006. Spherical Slepian functions and the polar gap in geodesy. Geophysical Journal International 166(3). Simons, F., Dahlen, F., Wieczorek, M. A., 2006. Spatiospectral concentration on a sphere. SIAM Review 48(3). Wieczorek, M., Simons, F., 2005. Localized spectral analysis on the sphere. Geophysical Journal International 162.

  12. Use of Harmonic Inversion Techniques in Semiclassical Quantization and Analysis of Quantum Spectra

    E-print Network

    J. Main

    1999-02-11

    Harmonic inversion is introduced as a powerful tool for both the analysis of quantum spectra and semiclassical periodic orbit quantization. The method allows to circumvent the uncertainty principle of the conventional Fourier transform and to extract dynamical information from quantum spectra which has been unattainable before, such as bifurcations of orbits, the uncovering of hidden ghost orbits in complex phase space, and the direct observation of symmetry breaking effects. The method also solves the fundamental convergence problems in semiclassical periodic orbit theories - for both the Berry-Tabor formula and Gutzwiller's trace formula - and can therefore be applied as a novel technique for periodic orbit quantization, i.e., to calculate semiclassical eigenenergies from a finite set of classical periodic orbits. The advantage of periodic orbit quantization by harmonic inversion is the universality and wide applicability of the method, which will be demonstrated in this work for various open and bound systems with underlying regular, chaotic, and even mixed classical dynamics. The efficiency of the method is increased, i.e., the number of orbits required for periodic orbit quantization is reduced, when the harmonic inversion technique is generalized to the analysis of cross-correlated periodic orbit sums. The method provides not only the eigenenergies and resonances of systems but also allows the semiclassical calculation of diagonal matrix elements and, e.g., for atoms in external fields, individual non-diagonal transition strengths. Furthermore, it is possible to include higher order terms of the hbar expanded periodic orbit sum to obtain semiclassical spectra beyond the Gutzwiller and Berry-Tabor approximation.

  13. Electrical Rhythms Revealed by Harmonic Analysis of a High-Resolution Cardiogram.

    PubMed

    Revenko, S V; Selector, L Ya; Gavrilov, I Yu; Nesterov, A V; Limonov, E V; Mudraya, I S; Kirpatovskii, V I

    2015-05-01

    The front-end low-noise electronic amplifiers and high-throughput computing systems made it possible to record ECG with a high resolution in the low-frequency range including the respiration and Mayer frequencies and to analyze ECG with digital filtering technique and harmonic analysis. These tools yielded ECG spectra of narcotized rats, which contained the characteristic pulsatile triplets and pentaplets with splitting constant equal to respiration rate, as well as the peaks at respiration and Mayer frequencies. The harmonic analysis of ECG determined the frequency parameters employed to tune the software bandpass filters, which revealed the respiratory (R) and Mayer (M) waves in the time domain with the amplitudes of 20-30 ?V amounting to 5% ECG amplitude. The depolarizing myorelaxant succinylcholine chloride capable to trigger various types of arrhythmias, transiently increased R-wave, inhibited M-wave, and provoked a negative U-wave within a heartbeat ECG cycle synchronously with inspiration. It is hypothesized that M-, R-, and U-waves in ECG reflect cardiotropic activity of autonomic nervous system. The respective spectral peaks in ECG can be employed to assess intensity of sympathetic and parasympathetic cardiotropic influences, their balance, and the risk of arrhythmias. PMID:26033579

  14. Finite Element Analysis of Forced Vibration for a Pipe Conveying Harmonically Pulsating Fluid

    NASA Astrophysics Data System (ADS)

    Seo, Young Soo; Jeong, Weui Bong; Jeong, Seok Hyeon; Oh, Jun Suk; Yoo, Wan Suk

    It is well known that the natural frequencies of a pipe become lower as uniform internal fluid velocity increases. The pipe becomes unstable if the fluid is faster than the critical velocity. But in the case of a pipe conveying harmonically pulsating fluid, resonances will occur even though the mean velocity of the fluid is below the critical velocity. Therefore, for improved analysis, the effects of pulsating fluid in the pipe should also be taken into consideration. In this study, a finite element formulation for the pipe was carried out while taking into consideration the effects of the fluid pulsating harmonically in the pipe. The damping and stiffness matrices in the finite element equation vary with time. A stability analysis based on the Bolotin method was carried out. And, a method to directly estimate the forced response of the pipe that does not need to solve a time data from time-variant system is presented. Several numerical examples are given in this paper that validate of this method.

  15. Proc. 1999 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, New Paltz, New York, Oct. 1720, 1999 ANALYSIS AND ENHANCEMENT OF LOCALLY HARMONIC SIGNALS USING

    E-print Network

    Cappé, Olivier

    , New York, Oct. 17­20, 1999 ANALYSIS AND ENHANCEMENT OF LOCALLY HARMONIC SIGNALS USING ADAPTIVE MULTI for which the duration of the analysis frame is tuned independently for each harmonic depending on the local This paper is concerned with the analysis/synthesis and enhance­ ment of signals that can be efficiently

  16. Abstract--This paper presents the harmonic analysis of offshore wind farm (OWF) models with full converters

    E-print Network

    Bak, Claus Leth

    Abstract--This paper presents the harmonic analysis of offshore wind farm (OWF) models with full analysis, offshore wind farm, wind turbine, validation with measurements I. INTRODUCTION HE tendency. Nowadays wind turbines are often grouped in large wind farms, installed offshore and connected directly

  17. Physics: A New Reactor Physics Analysis Toolkit

    SciTech Connect

    C. Rabiti; Y. Wang; G. Palmiotti; H. Hiruta; J. Cogliati; A. Alfonsi

    2011-06-01

    In the last year INL has internally pursued the development of a new reactor analysis tool: PHISICS. The software is built in a modular approach to simplify the independent development of modules by different teams and future maintenance. Most of the modules at the time of this summary are still under development (time dependent transport driver, depletion, cross section I/O and interpolation, generalized perturbation theory), while the transport solver INSTANT (Intelligent Nodal and Semi-structured Treatment for Advanced Neutron Transport) has already been widely used1, 2, 3, 4. For this reason we will focus mainly on the presentation of the transport solver INSTANT

  18. Exact Analysis of the Adiabatic Invariants in Time-Dependent Harmonic Oscillator

    E-print Network

    Marko Robnik; Valery G. Romanovski

    2005-06-16

    The theory of adiabatic invariants has a long history and important applications in physics but is rarely rigorous. Here we treat exactly the general time-dependent 1-D harmonic oscillator, $\\ddot{q} + \\omega^2(t) q=0$ which cannot be solved in general. We follow the time-evolution of an initial ensemble of phase points with sharply defined energy $E_0$ and calculate rigorously the distribution of energy $E_1$ after time $T$, and all its moments, especially its average value $\\bar{E_1}$ and variance $\\mu^2$. Using our exact WKB-theory to all orders we get the exact result for the leading asymptotic behaviour of $\\mu^2$.

  19. Three-dimensional analysis of collective relativistic electron motion and coherent harmonic generation driven by an intense pulsed Gaussian beam

    SciTech Connect

    Tsaur Ginyih; Wang Jyhpyng [Department of Mathematics, Tunghai University, Taichung 407, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, P. O. Box 23-166, Taipei 106, Taiwan (China)

    2007-12-15

    Collective electron motion driven by intense laser pulses can become highly nonlinear as results of the vxB term in the Lorentz force and the relativistic mass increase effect. These nonlinear effects are the bases of many nonlinear phenomena in high-field physics. Using paraxial expansion we analyzed the three-dimensional collective relativistic motion of electrons driven by an intense pulsed Gaussian beam. We solved the three-dimensional velocity field and density field of the electrons, as well as the scalar potential field resulting from the electron density modulation, in terms of the vector potential of the laser pulse in the highly relativistic regime. From the solutions we derived an analytical expression for the nonlinear oscillation of the electric current density. The results are applied to a systematical analysis of coherent relativistic harmonic generation as a demonstration of the applications. Extensive comparison with published experimental data is made, and the remarkable agreement provides a strong support to the analysis presented in this paper.

  20. Digital pathology and image analysis augment biospecimen annotation and biobank quality assurance harmonization.

    PubMed

    Wei, Bih-Rong; Simpson, R Mark

    2014-03-01

    Standardization of biorepository best practices will enhance the quality of translational biomedical research utilizing patient-derived biobank specimens. Harmonization of pathology quality assurance procedures for biobank accessions has lagged behind other avenues of biospecimen research and biobank development. Comprehension of the cellular content of biorepository specimens is important for discovery of tissue-specific clinically relevant biomarkers for diagnosis and treatment. While rapidly emerging technologies in molecular analyses and data mining create focus on appropriate measures for minimizing pre-analytic artifact-inducing variables, less attention gets paid to annotating the constituent makeup of biospecimens for more effective specimen selection by biobank clients. Both pre-analytic tissue processing and specimen composition influence acquisition of relevant macromolecules for downstream assays. Pathologist review of biorepository submissions, particularly tissues as part of quality assurance procedures, helps to ensure that the intended target cells are present and in sufficient quantity in accessioned specimens. This manual procedure can be tedious and subjective. Incorporating digital pathology into biobank quality assurance procedures, using automated pattern recognition morphometric image analysis to quantify tissue feature areas in digital whole slide images of tissue sections, can minimize variability and subjectivity associated with routine pathologic evaluations in biorepositories. Whole-slide images and pathologist-reviewed morphometric analyses can be provided to researchers to guide specimen selection. Harmonization of pathology quality assurance methods that minimize subjectivity and improve reproducibility among collections would facilitate research-relevant specimen selection by investigators and could facilitate information sharing in an integrated network approach to biobanking. PMID:24362266

  1. Flood detection from multi-temporal SAR data using harmonic analysis and change detection

    NASA Astrophysics Data System (ADS)

    Schlaffer, Stefan; Matgen, Patrick; Hollaus, Markus; Wagner, Wolfgang

    2015-06-01

    Flood mapping from Synthetic Aperture Radar (SAR) data has attracted considerable attention in recent years. Most available algorithms typically focus on single-image techniques which do not take into account the backscatter signature of a land surface under non-flooded conditions. In this study, harmonic analysis of a multi-temporal time series of >500 ENVISAT Advanced SAR (ASAR) scenes with a spatial resolution of 150 m was used to characterise the seasonality in backscatter under non-flooded conditions. Pixels which were inundated during a large-scale flood event during the summer 2007 floods of the River Severn (United Kingdom) showed strong deviations from normal seasonal behaviour as inferred from the harmonic model. The residuals were classified by means of an automatic threshold optimisation algorithm after masking out areas which are unlikely to be flooded using a topography-derived index. The results were validated against a reference dataset derived from high-resolution airborne imagery. For the water class, accuracies > 80% were found for non-urban land uses. A slight underestimation of the reference flood extent can be seen, mostly due to the lower spatial resolution of the ASAR imagery. Finally, an outlook for the proposed algorithm is given in the light of the Sentinel-1 mission.

  2. Harmonic Analysis and Superconformal Gauge Theories in Three Dimensions from AdS/CFT Correspondence

    E-print Network

    Leonardo Gualtieri

    2000-04-15

    In this thesis I review various aspects of the AdS_4/CFT_3 correspondence, where AdS_4 supergravity arises from compactification of M-theory on a coset space G/H and preserves Nharmonic analysis on the homogeneous space G/H. This spectrum can be matched with the candidate conformal theory on the boundary, in this way providing very non-trivial checks of the AdS/CFT correspondence. Furthermore, this spectrum can be useful to study the representation theory of N-extended supersymmetry on AdS_4, namely representation theory for the superalgebra of Osp(N|4). I review Osp(N|4) representation theory, and derive the translation vocabulary between states of AdS_4 supergravity and conformal superfields on the boundary, by means of the double interpretation of Osp(N|4) unitary irreducible representations. In the cases of N=2,3, using results from harmonic analysis I give the complete structure of all supermultiplets. Harmonic analysis as a method to determine spectra of supergravity compactifications is explained. Calculations are explicitly performed in the case G/H=M^111=(SU(3)xSU(2)xU(1))/(SU(2)xU(1)xU(1)), preserving N=2 supersymmetries. For this manifold, and also for the case G/H=Q^111=(SU(2)x SU(2)xSU(2))/(U(1)xU(1)), I describe the construction of a candidate dual superconformal theory on the boundary. This construction is based on geometrical insight provided by the properties of the metric cone C(G/H) transverse to the M2-brane worldvolume.

  3. Analysis of Astrophysics and Particle Physics Data

    E-print Network

    California at Santa Cruz, University of

    Analysis of Astrophysics and Particle Physics Data using Optimal Segmentation Jeffrey #12;Outline Goal: Detect/Characterize Local Structures Data Cells Piecewise Constant Models Fitness Functions Optimization Error analysis Interpretation Extension to Higher Dimensions #12;The Main Goal

  4. Harmonic analysis of cosmic microwave background data I: ring reductions and point-source catalogue

    E-print Network

    Floor van Leeuwen; Anthony D. Challinor; Daniel J. Mortlock; Mark A. J. Ashdown; Michael P. Hobson; Anthony N. Lasenby; George P. Efstathiou; E. Paul. S. Shellard; Dipak Munshi; Vladislav Stolyarov

    2001-12-12

    We present a harmonic model for the data analysis of an all-sky cosmic microwave background survey, such as Planck, where the survey is obtained through ring-scans of the sky. In this model, resampling and pixelisation of the data are avoided. The spherical transforms of the sky at each frequency, in total intensity and polarization, as well as the bright-point-source catalogue, are derived directly from the data reduced onto the rings. Formal errors and the most significant correlation coefficients for the spherical transforms of the frequency maps are preserved. A clean and transparent path from the original samplings in the time domain to the final scientific products is thus obtained. The data analysis is largely based on Fourier analysis of rings; the positional stability of the instrument's spin axis during these scans is a requirement for the data model and is investigated here for the Planck satellite. Brighter point sources are recognised and extracted as part of the ring reductions and, on the basis of accumulated data, used to build a catalogue. The analysis of the rings is performed iteratively, involving a range of geometric and detector response calibrations. The reconstructed spherical transforms of the sky form the input to the subsequent analysis stages. Although the methods in this paper were developed with the data processing for Planck in mind, many aspects should have wider application, such as in the construction of real-space pixelised maps. (Abridged)

  5. PAT: The CMS Physics Analysis Toolkit

    Microsoft Academic Search

    W. Adam; V. Adler; B. Hegner; L. Lista; S. Lowette; P. Maksimovic; G. Petrucciani; S. Rappoccio; F. Ronga; R. Tenchini; R. Wolf

    2010-01-01

    The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within Physics Analysis Groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some

  6. Tools for Physics Analysis in CMS

    Microsoft Academic Search

    Andreas Hinzmann

    2011-01-01

    The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within physics analysis groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some

  7. PAT: the CMS Physics Analysis Toolkit

    Microsoft Academic Search

    W Adam; V Adler; B Hegner; L Lista; S Lowette; P Maksimovic; G Petrucciani; S Rappoccio; F Ronga; R Tenchini; R Wolf

    2009-01-01

    The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within Physics Analysis Groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some

  8. A spherical harmonic transform spectral analysis of a localized surface plasmon on a gold nano shell.

    PubMed

    Berco, Dan; Hu, Chin-Kun

    2014-11-15

    We perform a study of the localized surface plasmon (LSP) modes of a gold nano shell having a silica core by means of discrete dipole approximation (DDA) and spherical harmonics transform for selected wavelengths. We demonstrate an efficient solution for the near and intermediate field terms by the dyadic Green function approach and determine the optical extinction efficiency by the far field term. Using this approach, we combine the advantages of a spectral analysis along with a DDA flexibility to solve an arbitrary shaped model and demonstrate the LSP dominant mode wavelength dependency. Our approach provides a metric which may be used to quantify the effects of minor changes in the model structure, or the external dielectric environment, in optical experiments. PMID:25327719

  9. Advances in High-harmonic Fast Wave Physics in the National Spherical Torus Experiment

    SciTech Connect

    Taylor, G; Hosea, J C; LeBlanc, B P; Phillips, C K; Podesta, M; Valeo, E J; Wilson, J R; Ahn, J -W; Chen, G; Green, D L; Jaeger, E F; Maingi, R; Ryan, P M; Wilgen, J B; Heidbrink, W W; Liu, D; Bonoli, P T; Brecht, T; Choi, M

    2009-12-01

    Improved core high-harmonic fast wave (HHFW) heating at longer wavelengths and during start-up and plasma current ramp-up, has now been obtained by lowering the edge density with lithium wall conditioning, thereby moving the critical density for perpendicular fast-wave propagation away from the vessel wall. Lithium conditioning allowed significant HHFW core electron heating of deuterium neutral beam injection (NBI) fuelled H-mode plasmas to be observed for the first time. Large edge localized modes were observed immediately after the termination of rf power. Visible and infrared camera images show that fast wave interactions can deposit considerable rf energy on the outboard divertor. HHFW-generated parametric decay instabilities were observed to heat ions in the plasma edge and may be the cause for a measured drag on edge toroidal rotation during HHFW heating. A significant enhancement in neutron rate and fast-ion profile were measured in NBI-fuelled plasmas when HHFW heating was applied. __________________________________________________

  10. Application of differential quadrature (DQ) and harmonic differential quadrature (HDQ) for buckling analysis of thin isotropic plates and elastic columns

    Microsoft Academic Search

    Ömer Civalek

    2004-01-01

    The main purpose of this study is to compare the methods of differential quadrature (DQ) and harmonic differential quadrature (HDQ). For this purpose, DQ and HDQ methods are presented for buckling, bending, and free vibration analysis of thin isotropic plates and columns. Plates of different shapes such as rectangular, circular, square, skew, trapezoidal, annular, and sectorial plate subjected to different

  11. Harmonic analysis of a synchronous machine feeding a nonlinear load by a time-stepping finite element simulation

    Microsoft Academic Search

    S. I. Nabeta; A. B. Dietrich; A. Rocco

    1999-01-01

    This paper presents a time-stepping finite element simulation of a synchronous machine feeding a fully controlled three-phase rectifier. The simulation provided the current and voltage waveforms which allowed the analysis of harmonics. In order to validate the numerical method the simulation results were compared to those obtained by tests

  12. Harmonic operation of STW filters

    Microsoft Academic Search

    R. L. Baer; C. A. FLory

    1988-01-01

    The physical mechanism causing the propagation loss of surface transverse wave (STW) devices during harmonic operation is modeled and analyzed. It is found that as the mode frequency is pushed beyond the fundamental, the dominant Bloch component of the STW solution passes through the higher spatial harmonics. In these frequency regions, the lower harmonic components which contribute (perhaps weakly) to

  13. A comparative analysis of total harmonic distortion in TPRD and RNSIC

    Microsoft Academic Search

    C. Filote; C. Ciufudean; A. M. Cozgarea

    2009-01-01

    The total harmonic distortion (THD) monitoring is an important challenge in the industrial and office building environment. The IEEE-519 and IEC 61000-3 standards limit the individual harmonics current as well as the THD for nonlinear power electronic loads. A harmonic current distortion comparative study of a classical three-phase rectifier diode (TPRD) and rectifier with near sinusoidal currents (RNSIC) are presented.

  14. High Harmonic Configurations of Cosmic Strings: An Analysis of Self-Intersections

    E-print Network

    Xavier A. Siemens; T. W. B. Kibble

    1994-12-06

    A general formulation for describing odd-harmonic cosmic strings is developed and used to determine the self-intersection properties of high-harmonic loops. This is important because loop formation mechanisms produce high-harmonic components (kinks) which can only be eliminated very slowly by gravitational radiation, damping by the dense surrounding plasma in the era of string formation, or by the expansion of the Universe. For the class of loops examined it has been found that in the high-harmonic limit, essentially all cosmic loops self-intersect.

  15. Definitions of non-stationary vibration power for time-frequency analysis and computational algorithms based upon harmonic wavelet transform

    NASA Astrophysics Data System (ADS)

    Heo, YongHwa; Kim, Kwang-joon

    2015-02-01

    While the vibration power for a set of harmonic force and velocity signals is well defined and known, it is not as popular yet for a set of stationary random force and velocity processes, although it can be found in some literatures. In this paper, the definition of the vibration power for a set of non-stationary random force and velocity signals will be derived for the purpose of a time-frequency analysis based on the definitions of the vibration power for the harmonic and stationary random signals. The non-stationary vibration power, defined as the short-time average of the product of the force and velocity over a given frequency range of interest, can be calculated by three methods: the Wigner-Ville distribution, the short-time Fourier transform, and the harmonic wavelet transform. The latter method is selected in this paper because band-pass filtering can be done without phase distortions, and the frequency ranges can be chosen very flexibly for the time-frequency analysis. Three algorithms for the time-frequency analysis of the non-stationary vibration power using the harmonic wavelet transform are discussed. The first is an algorithm for computation according to the full definition, while the others are approximate. Noting that the force and velocity decomposed into frequency ranges of interest by the harmonic wavelet transform are constructed with coefficients and basis functions, for the second algorithm, it is suggested to prepare a table of time integrals of the product of the basis functions in advance, which are independent of the signals under analysis. How to prepare and utilize the integral table are presented. The third algorithm is based on an evolutionary spectrum. Applications of the algorithms to the time-frequency analysis of the vibration power transmitted from an excitation source to a receiver structure in a simple mechanical system consisting of a cantilever beam and a reaction wheel are presented for illustration.

  16. Gastrectomy and D2 Lymphadenectomy for Gastric Cancer: A Meta-Analysis Comparing the Harmonic Scalpel to Conventional Techniques

    PubMed Central

    Cheng, Hang; Hsiao, Chia-Wen; Clymer, Jeffrey W.; Schwiers, Michael L.; Tibensky, Bryanna N.; Patel, Leena; Ferko, Nicole C.; Chekan, Edward

    2015-01-01

    The ultrasonic Harmonic scalpel has demonstrated clinical and surgical benefits in dissection and coagulation. To evaluate its use in gastrectomy, we conducted a systematic review and meta-analysis of randomized controlled trials comparing the Harmonic scalpel to conventional techniques in gastrectomy for patients with gastric cancer. International databases were searched without language restrictions for comparisons in open or laparoscopic gastrectomy and lymphadenectomy. The meta-analysis used a random-effects model for all outcomes; continuous variables were analyzed for mean differences and dichotomous variables were analyzed for risk ratios. Sensitivity analyses were conducted for study quality, type of conventional technique, and imputation of study results. Ten studies (N = 935) met the inclusion criteria. Compared with conventional hemostatic techniques, the Harmonic scalpel demonstrated significant reductions in operating time (?27.5?min; P < 0.001), intraoperative blood loss (?93.2?mL; P < 0.001), and drainage volume (?138.8?mL; P < 0.001). Results were numerically higher for conventional techniques for hospital length of stay, complication risk, and transfusions but did not reach statistical significance. Results remained robust to sensitivity analyses. This meta-analysis demonstrates the clear advantages of using the Harmonic scalpel compared to conventional techniques, with improvements demonstrated across several outcome measures for patients undergoing gastrectomy and lymphadenectomy.

  17. Recent Developments in High-Harmonic Fast Wave Physics in NSTX

    SciTech Connect

    B.P. LeBlanc, R.E. Bell, P. Bonoli, R. Harvey, W.W. Heidbrink, J.C. Hosea, S.M. Kaye, D. Liu, R. Maingi, S.S. Medley, M. Ono, M. Podestà, C.K. Phillips, P.M. Ryan, A.L. Roquemore, G. Taylor, J.R. Wilson and the NSTX Team

    2010-10-06

    Understanding the interaction between ion cyclotron range of frequency (ICRF) fast waves and the fast-ions created by neutral beam injection (NBI) is critical for future devices such as ITER, which rely on a combination ICRF and NBI. Experiments in NSTX which use 30 MHz High-Harmonic Fast-Wave (HHFW) ICRF and NBI heating show a competition between electron heating via Landau damping and transit-time magnetic pumping, and radio-frequency wave acceleration of NBI generated fast ions. Understanding and mitigating some of the power loss mechanisms outside the last closed flux surface (LCFS) has resulted in improved HHFW heating inside the LCFS. Nevertheless a significant fraction of the HHFW power is diverted away from the enclosed plasma. Part of this power is observed locally on the divertor. Experimental observations point toward the radio-frequency (RF) excitation of surface waves, which disperse wave power outside the LCFS, as a leading loss mechanism. Lithium coatings lower the density at the antenna, thereby moving the critical density for perpendicular fast-wave propagation away from the antenna and surrounding material surfaces. Visible and infrared imaging reveal flows of RF power along open field lines into the divertor region. In L-mode -- low average NBI power -- conditions, the fast-ion D-alpha (FIDA) diagnostic measures a near doubling and broadening of the density profile of the upper energetic level of the fast ions concurrent with the presence of HHFW power launched with k// =-8m-1. We are able to heat NBI-induced H-mode plasmas with HHFW. The captured power is expected to be split between absorption by the electrons and absorption by the fast ions, based on TORIC calculation. In the case discussed here the Te increases over the whole profile when ~2MW of HHFW power with antenna k// =13m-1 is applied after the H-mode transition.. But somewhat unexpectedly fast-ion diagnostics do not observe a change between the HHFW heated NBI discharge and the reference NBI only plasma, although an increase in neutron production is measured. __________________________________________________

  18. Permanent Magnet Temperature Analysis Considering PWM Carrier Harmonics for Interior Permanent Magnet Synchronous Generator in Hybrid Vehicles

    Microsoft Academic Search

    Munehiro Kamiya; Hideya Awata; Tetsuya Miura; Yasuhide Yagyu; Takashi Kosaka; Nobuyuki Matsui

    2007-01-01

    In this paper, we investigate into an approach to predict the magnet temperature in interior permanent magnet synchronous generator for mass-produced front engine rear drive hybrid vehicles. To achieve an accurate thermal analysis, the generator losses under PWM converter drive are firstly calculated by 3D-FEM using measured current waveform including PWM carrier harmonics. As an approach for thermal analysis, a

  19. On the link atom distance in the ONIOM scheme. An harmonic approximation analysis

    Microsoft Academic Search

    Etienne Derat; James Bouquant; Stéphane Humbel

    2003-01-01

    The link atom distance of the ONIOM scheme is studied and analyzed with a harmonic approximation. It is shown that, when an appropriate low level is used, the ONIOM absolute energy does not depend on the choice of this distance, except for clearly ‘unreasonable’ distances. A strategy to analyze the low level is proposed on the basis of this harmonic

  20. On the use of windows for harmonic analysis with the discrete Fourier transform

    Microsoft Academic Search

    FREDRIC J. HARRIS

    1978-01-01

    This paper makes available a concise review of data windows and their affect on the detection of harmonic signals in the presence of broad-band noise, and in the presence of nearby strong harmonic interference. We also call attention to a number of common errors in the application of windows when used with the fast Fourier transform. This paper includes a

  1. Space-harmonic analysis of periodically supported beams: response to convected random loading

    Microsoft Academic Search

    D. J. Mead; K. K. Pujara

    1971-01-01

    The solution for the response of stiffened beams due to a spatial and temporal harmonic pressure has been obtained in the form of a particular series of space harmonics, evolved from considerations of progressive wave propagation. The superiority of this method over the classical normal mode approach is indicated. It is applied to obtain the r.m.s. curvature at a point

  2. Analysis of Current Harmonics in 3kV DC Catenary Caused by Specific Current Harmonics of an Asynchronous Motor

    NASA Astrophysics Data System (ADS)

    Lewandowski, Miros?aw

    2010-01-01

    The mathematical model of vehicle supply system as well as the mathematical model of main circuit of locomotive with asynchronous motors have been described in this article. The necessity of analysis of disturbances caused by distorted current run of drive motors emerged together with the introduction of high power vehicles with power electronic converters. Analysis of the compatibility of traction high current circuits with circuits of the signal and traffic control systems requires the knowledge of current spectrum in a catenary, which has been taken by a vehicle. The author has described the algebraic method of calculating of the spectrum amplitudes in a catenary. It does not require laborious and time-consuming simulations of a system, which considerably decreases preliminary costs of designation and dimensioning of a vehicle drive system.

  3. Spherical cap harmonic analysis of magnetic variations data from mainland Australia

    NASA Astrophysics Data System (ADS)

    Stening, R. J.; Reztsova, T.; Ivers, D.; Turner, J.; Winch, D. E.

    2008-12-01

    Spherical cap harmonic analysis (SCHA) has been applied to geomagnetic data from an array of magnetometers deployed across the Australian mainland during 1989 90 in order to examine features of the ionospheric Sq current system. The external contours, corresponding to ionospheric currents, are generally in good agreement with the data in that the direction of current flow is perpendicular to the measured horizontal magnetic field. The derived internal (induced) current systems are less reliable but exhibit fairly consistent behaviour on some occasions. As the Sq current system whorl passes over Australia, the reversed internal current whorl lags by a bit less than an hour. When the external system moves off the continent into the Indian Ocean, the derived internal system sometimes appears to remain over the continent for about two hours but this is found to be caused by the large coastal effect in the west. The variations obtained from the analysis at particular sites are compared with the original data and give generally good agreement. Internal and external variations at several sites are derived and behave as expected to some extent. In particular we find that the internal component of the vertical element adds to the external component on the west coast but subtracts from it on the east coast. Further analyses are performed using data from the CM4 model. The SCHA gives a separation of internal and external components in good agreement with the original for the horizontal CM4 magnetic fields while the agreement is not so good for the vertical component.

  4. Almansi Theorems in Umbral Clifford Analysis and the Quantum Harmonic Oscillator

    E-print Network

    Guangbin Ren; Nelson Faustino

    2009-01-29

    We introduce the Umbral calculus into Clifford analysis starting from the abstract of the Heisenberg commutation relation $[\\frac{d}{dx}, x] = {\\bf id}$. The Umbral Clifford analysis provides an effective framework in continuity and discreteness. In this paper we consider functions defined in a star-like domain $\\Omega \\subset \\BR^n$ with values in the Umbral Clifford algebra $C\\ell_{0,n}'$ which are Umbral polymonogenic with respect to the (left) Umbral Dirac operator $D'$, i.e. they belong to the kernel of $(D')^k$. We prove that any polymonogenic function $f$ has a decomposition of the form $$f=f_1+ x'f_2 + ... + (x')^{k-1}f_k,$$ where $x'=x'_1e_1 + ... + x'_ne_n$ and $f_j, j=1,..., k,$ are Umbral monogenic functions. As examples, this result recoveries the continuous version of the classical Almansi theorem for derivatives and establishes the discrete version of Almansi theorem for difference operator. The approach also provides a similar result in quantum field about Almansi decomposition related to Hamilton operators. Some concrete examples will presented for the discrete analog version of Almansi Decomposition and for the quantum harmonic oscillator.

  5. A Back-to-Front Derivation: The Equal Spacing of Quantum Levels Is a Proof of Simple Harmonic Oscillator Physics

    ERIC Educational Resources Information Center

    Andrews, David L.; Romero, Luciana C. Davila

    2009-01-01

    The dynamical behaviour of simple harmonic motion can be found in numerous natural phenomena. Within the quantum realm of atomic, molecular and optical systems, two main features are associated with harmonic oscillations: a finite ground-state energy and equally spaced quantum energy levels. Here it is shown that there is in fact a one-to-one…

  6. Advanced analysis methods in particle physics

    SciTech Connect

    Bhat, Pushpalatha C.; /Fermilab

    2010-10-01

    Each generation of high energy physics experiments is grander in scale than the previous - more powerful, more complex and more demanding in terms of data handling and analysis. The spectacular performance of the Tevatron and the beginning of operations of the Large Hadron Collider, have placed us at the threshold of a new era in particle physics. The discovery of the Higgs boson or another agent of electroweak symmetry breaking and evidence of new physics may be just around the corner. The greatest challenge in these pursuits is to extract the extremely rare signals, if any, from huge backgrounds arising from known physics processes. The use of advanced analysis techniques is crucial in achieving this goal. In this review, I discuss the concepts of optimal analysis, some important advanced analysis methods and a few examples. The judicious use of these advanced methods should enable new discoveries and produce results with better precision, robustness and clarity.

  7. Using physical activity for user behavior analysis

    Microsoft Academic Search

    Gerald Bieber; Christian Peter

    2008-01-01

    Physical activity is one important aspect in user behavior analysis. Abnormal movement behavior might be an indicator for an inappropriate lifestyle, insufficient social inclusion, or generally disadvantageous life conditions which might call for medical treatment. Assistive technologies can make use of information on the physical activity of e.g. residents of a nursing home or elderly patients living alone at home.

  8. Surface second-harmonic generation from coupled spherical plasmonic nanoparticles: Eigenmode analysis and symmetry properties

    NASA Astrophysics Data System (ADS)

    Butet, Jérémy; Dutta-Gupta, Shourya; Martin, Olivier J. F.

    2014-06-01

    The surface second-harmonic generation from interacting spherical plasmonic nanoparticles building different clusters (symmetric and asymmetric dimers, trimers) is theoretically investigated. The plasmonic eigenmodes of the nanoparticle clusters are first determined using an ab initio approach based on the Green's functions method. This method provides the properties, such as the resonant wavelengths, of the modes sustained by a given cluster. The fundamental and second-harmonic responses of the corresponding clusters are then calculated using a surface integral method. The symmetry of both the linear and nonlinear responses is investigated, as well as their relationship. It is shown that the second-harmonic generation can be significantly enhanced when the fundamental field is such that its second harmonic matches modes with suitable symmetry. The role played by the nanogaps in second-harmonic generation is also underlined. The results presented in this article demonstrate that the properties of the second-harmonic generation from coupled metallic nanoparticles cannot be fully predicted from their linear response only, while, on the other hand, a detailed knowledge of the underlying modal structure can be used to optimize the generation of the second harmonic.

  9. Physical phenomena disturbing LIBS analysis

    Microsoft Academic Search

    A. Sarzynski; W. Skrzeczanowski; J. Marczak

    2007-01-01

    An influence of some physical phenomena disturbing correct interpretation of LIBS spectra is described in the paper. The following phenomena were investigated: a way of laser beam focusing (power density), laser spark in air, spectral line broadening, apparatus efficiency and resolution, and an influence of those factors on LIBS spectra as well. They are particularly important for quantitative LIBS measurements.

  10. RUSHMAPS: Real-Time Uploadable Spherical Harmonic Moment Analysis for Particle Spectrometers

    NASA Technical Reports Server (NTRS)

    Figueroa-Vinas, Adolfo

    2013-01-01

    RUSHMAPS is a new onboard data reduction scheme that gives real-time access to key science parameters (e.g. moments) of a class of heliophysics science and/or solar system exploration investigation that includes plasma particle spectrometers (PPS), but requires moments reporting (density, bulk-velocity, temperature, pressure, etc.) of higher-level quality, and tolerates a lowpass (variable quality) spectral representation of the corresponding particle velocity distributions, such that telemetry use is minimized. The proposed methodology trades access to the full-resolution velocity distribution data, saving on telemetry, for real-time access to both the moments and an adjustable-quality (increasing quality increases volume) spectral representation of distribution functions. Traditional onboard data storage and downlink bandwidth constraints severely limit PPS system functionality and drive cost, which, as a consequence, drives a limited data collection and lower angular energy and time resolution. This prototypical system exploit, using high-performance processing technology at GSFC (Goddard Space Flight Center), uses a SpaceCube and/or Maestro-type platform for processing. These processing platforms are currently being used on the International Space Station as a technology demonstration, and work is currently ongoing in a new onboard computation system for the Earth Science missions, but they have never been implemented in heliospheric science or solar system exploration missions. Preliminary analysis confirms that the targeted processor platforms possess the processing resources required for realtime application of these algorithms to the spectrometer data. SpaceCube platforms demonstrate that the target architecture possesses the sort of compact, low-mass/power, radiation-tolerant characteristics needed for flight. These high-performing hybrid systems embed unprecedented amounts of onboard processing power in the CPU (central processing unit), FPGAs (field programmable gate arrays), and DSP (digital signal processing) elements. The fundamental computational algorithm de constructs 3D velocity distributions in terms of spherical harmonic spectral coefficients (which are analogous to a Fourier sine-cosine decomposition), but uses instead spherical harmonics Legendre polynomial orthogonal functions as a basis for the expansion, portraying each 2D angular distribution at every energy or, geometrically, spherical speed-shell swept by the particle spectrometer. Optionally, these spherical harmonic spectral coefficients may be telemetered to the ground. These will provide a smoothed description of the velocity distribution function whose quality will depend on the number of coefficients determined. Successfully implemented on the GSFC-developed processor, the capability to integrate the proposed methodology with both heritage and anticipated future plasma particle spectrometer designs is demonstrated (with sufficiently detailed design analysis to advance TRL) to show specific science relevancy with future HSD (Heliophysics Science Division) solar-interplanetary, planetary missions, sounding rockets and/or CubeSat missions.

  11. Harmonic analysis for the characterization and correction of geometric distortion in MRI

    SciTech Connect

    Tadic, Tony, E-mail: ttadic@gmail.com; Stanescu, Teodor [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto M5S 3E2 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto M5S 3E2 (Canada); Department of Medical Biophysics, University of Toronto, Toronto M5G 1L7 (Canada)

    2014-11-01

    Purpose: Magnetic resonance imaging (MRI) is gaining widespread use in radiation therapy planning, patient setup verification, and real-time guidance of radiation delivery. Successful implementation of these technologies relies on the development of simple and efficient methods to characterize and monitor the geometric distortions arising due to system imperfections and gradient nonlinearities. To this end, the authors present the theory and validation of a novel harmonic approach to the quantification of system-related distortions in MRI. Methods: The theory of spatial encoding in MRI is applied to demonstrate that the 3D distortion vector field (DVF) is given by the solution of a second-order boundary value problem (BVP). This BVP is comprised of Laplace’s equation and a limited measurement of the distortion on the boundary of a specified region of interest (ROI). An analytical series expansion solving this BVP within a spherical ROI is obtained, and a statistical uncertainty analysis is performed to determine how random errors in the boundary measurements propagate to the ROI interior. This series expansion is then evaluated to obtain volumetric DVF mappings that are compared to reference data obtained on a 3 T full-body scanner. This validation is performed within two spheres of 20 cm diameter (one centered at the scanner origin and the other offset +3 cm along each of the transverse directions). Initially, a high-order mapping requiring measurements at 5810 boundary points is used. Then, after exploring the impact of the boundary sampling density and the effect of series truncation, a reduced-order mapping requiring measurements at 302 boundary points is evaluated. Results: The volumetric DVF mappings obtained from the harmonic analysis are in good agreement with the reference data. Following distortion correction using the high-order mapping, the authors estimate a reduction in the mean distortion magnitude from 0.86 to 0.42 mm and from 0.93 to 0.39 mm within the central and offset ROIs, respectively. In addition, the fraction of points with a distortion magnitude greater than 1 mm is reduced from 35.6% to 2.8% and from 40.4% to 1.5%, respectively. Similarly, following correction using the reduced-order mapping, the mean distortion magnitude reduces to 0.45–0.42 mm within the central and offset ROIs, and the fraction of points with a distortion magnitude greater than 1 mm is reduced to 2.8% and 1.5%, respectively. Conclusions: A novel harmonic approach to the characterization of system-related distortions in MRI is presented. This method permits a complete and accurate mapping of the DVF within a specified ROI using a limited measurement of the distortion on the ROI boundary. This technique eliminates the requirement to exhaustively sample the DVF at a dense 3D array of points, thereby permitting the design of simple, inexpensive phantoms that may incorporate additional modules for auxiliary quality assurance objectives.

  12. The Harmonic Scalpel versus Conventional Hemostasis for Neck Dissection: A Meta-Analysis of the Randomized Controlled Trials

    PubMed Central

    Ren, Zhen-Hu; Xu, Jian-Lin; Fan, Teng-Fei; Ji, Tong; Wu, Han-Jiang; Zhang, Chen-Ping

    2015-01-01

    Objective Neck dissection is the most definitive and effective treatment for head and neck cancer. This systematic review aims to compare the efficacy and surgical outcomes of neck dissection between the harmonic scalpel and conventional surgical techniques and conduct a quantitative meta-analysis of the randomized trials. Methods Randomized controlled trials (RCTs) were identified from the major electronic databases (MEDLINE, EMBASE and Cochrane Library) using the keywords ‘‘harmonic scalpel’’ and ‘‘neck dissection,’’ and a quantitative meta-analysis was conducted. The operative time and intraoperative bleeding were the primary outcome measures, and other parameters assessed included the drainage fluid volume and length of hospital stay. Results Seven trials that met the inclusion criteria included 406 neck dissection cases (201 in the harmonic scalpel group). Compared with conventional surgical techniques, the HS group had an operative time that was significantly reduced by 29.3 minutes [mean difference: -29.29; 95% CI = (-44.26, -14.32); P=0.0001], a reduction in intraoperative bleeding by 141.1 milliliters [mean difference: -141.13; 95% CI = (-314.99, 32.73); P=0.11], and a reduction in drainage fluid volume by 64.9 milliliters [mean difference: -64.86; 95% CI = (-110.40, -19.32); P=0.005] , but it is not significant after removal of studies driving heterogeneity. There was no significant difference in the length of the hospital stay [mean difference: -0.21; 95% CI = (-0.48, 0.07); P=0.14]. Conclusion This systematic review showed that using the harmonic scalpel for neck dissection significantly reduces the operative time and drainage fluid volume and that it is not associated with an increased length of hospital stay or perioperative complications. Therefore, the harmonic scalpel method is safe and effective for neck dissection. However, the statistical heterogeneity was high. Further studies are required to substantiate our findings. PMID:26161897

  13. Physical phenomena disturbing LIBS analysis

    NASA Astrophysics Data System (ADS)

    Sarzy?ski, A.; Skrzeczanowski, W.; Marczak, J.

    2007-07-01

    An influence of some physical phenomena disturbing correct interpretation of LIBS spectra is described in the paper. The following phenomena were investigated: a way of laser beam focusing (power density), laser spark in air, spectral line broadening, apparatus efficiency and resolution, and an influence of those factors on LIBS spectra as well. They are particularly important for quantitative LIBS measurements. The presented measurement results clearly show that the correct elemental identification plays a significant role in artworks dating [5].

  14. Quantitative analysis of intrinsic skin aging in dermal papillae by in vivo harmonic generation microscopy.

    PubMed

    Liao, Yi-Hua; Kuo, Wei-Cheng; Chou, Sin-Yo; Tsai, Cheng-Shiun; Lin, Guan-Liang; Tsai, Ming-Rung; Shih, Yuan-Ta; Lee, Gwo-Giun; Sun, Chi-Kuang

    2014-09-01

    Chronological skin aging is associated with flattening of the dermal-epidermal junction (DEJ), but to date no quantitative analysis focusing on the aging changes in the dermal papillae (DP) has been performed. The aim of the study is to determine the architectural changes and the collagen density related to chronological aging in the dermal papilla zone (DPZ) by in vivo harmonic generation microscopy (HGM) with a sub-femtoliter spatial resolution. We recruited 48 Asian subjects and obtained in vivo images on the sun-protected volar forearm. Six parameters were defined to quantify 3D morphological changes of the DPZ, which we analyzed both manually and computationally to study their correlation with age. The depth of DPZ, the average height of isolated DP, and the 3D interdigitation index decreased with age, while DP number density, DP volume, and the collagen density in DP remained constant over time. In vivo high-resolution HGM technology has uncovered chronological aging-related variations in DP, and sheds light on real-time quantitative skin fragility assessment and disease diagnostics based on collagen density and morphology. PMID:25401037

  15. Modes of asymmetry: The application of harmonic analysis to symmetric quantum dynamics and quantum reference frames

    NASA Astrophysics Data System (ADS)

    Marvian, Iman; Spekkens, Robert W.

    2014-12-01

    Finding the consequences of symmetry for open-system quantum dynamics is a problem with broad applications, including describing thermal relaxation, deriving quantum limits on the performance of amplifiers, and exploring quantum metrology in the presence of noise. The symmetry of the dynamics may reflect a symmetry of the fundamental laws of nature or a symmetry of a low-energy effective theory, or it may describe a practical restriction such as the lack of a reference frame. In this paper, we apply some tools of harmonic analysis together with ideas from quantum information theory to this problem. The central idea is to study the decomposition of quantum operations—in particular, states, measurements, and channels—into different modes, which we call modes of asymmetry. Under symmetric processing, a given mode of the input is mapped to the corresponding mode of the output, implying that one can only generate a given output if the input contains all of the necessary modes. By defining monotones that quantify the asymmetry in a particular mode, we also derive quantitative constraints on the resources of asymmetry that are required to simulate a given asymmetric operation. We present applications of our results for deriving bounds on the probability of success in nondeterministic state transitions, such as quantum amplification, and a simplified formalism for studying the degradation of quantum reference frames.

  16. Quantitative analysis of intrinsic skin aging in dermal papillae by in vivo harmonic generation microscopy

    PubMed Central

    Liao, Yi-Hua; Kuo, Wei-Cheng; Chou, Sin-Yo; Tsai, Cheng-Shiun; Lin, Guan-Liang; Tsai, Ming-Rung; Shih, Yuan-Ta; Lee, Gwo-Giun; Sun, Chi-Kuang

    2014-01-01

    Chronological skin aging is associated with flattening of the dermal-epidermal junction (DEJ), but to date no quantitative analysis focusing on the aging changes in the dermal papillae (DP) has been performed. The aim of the study is to determine the architectural changes and the collagen density related to chronological aging in the dermal papilla zone (DPZ) by in vivo harmonic generation microscopy (HGM) with a sub-femtoliter spatial resolution. We recruited 48 Asian subjects and obtained in vivo images on the sun-protected volar forearm. Six parameters were defined to quantify 3D morphological changes of the DPZ, which we analyzed both manually and computationally to study their correlation with age. The depth of DPZ, the average height of isolated DP, and the 3D interdigitation index decreased with age, while DP number density, DP volume, and the collagen density in DP remained constant over time. In vivo high-resolution HGM technology has uncovered chronological aging-related variations in DP, and sheds light on real-time quantitative skin fragility assessment and disease diagnostics based on collagen density and morphology. PMID:25401037

  17. Correlation of the earth's rotation rate and the secular change of the geomagnetic field. [power spectra/harmonic analysis

    NASA Technical Reports Server (NTRS)

    Jin, R. S.

    1975-01-01

    Power spectral density analysis using Burg's maximum entropy method was applied to the geomagnetic dipole field and its rate of change for the years 1901 to 1969. Both spectra indicate relative maxima at 0.015 cycles/year and its harmonics. These maxima correspond approximately to 66, 33, 22, 17, 13, 11, and 9-year spectral lines. The application of the same analysis techniques to the length-of-day (l.o.d) fluctuations for the period 1865 to 1961 reveal similar spectral characteristics. Although peaks were observed at higher harmonics of the fundamental frequency, the 22-year and 11-year lines are not attributed unambiguously to the solar magnetic cycle and the solar cycle. It is suggested that the similarity in the l.o.d fluctuations and the dipole field variations is related to the motion within the earth's fluid core during the past one hundred years.

  18. HARMONIC-ERROR-ANALYSIS MEASUREMENTS OF DIPOLE AND QUADRLJPOLE MAGNETS AT LAWRENCE BERKELEY LABORATORY

    Microsoft Academic Search

    M. I. Green; P. J. Barale; D. H. Nelson; A. Van Dyke

    Error harmonics are detected using slowly rotating search-coil arrays feeding a digital integrator. The fundamental signal is detected during the first rota- tional cycle. The search-coil arrays are reconfigured to \\

  19. Experimental observation and model analysis of second-harmonic generation in a plasma-metamaterial composite

    NASA Astrophysics Data System (ADS)

    Iwai, Akinori; Nakamura, Yoshihiro; Bambina, Alexandre; Sakai, Osamu

    2015-05-01

    We observed enhanced second-harmonic-wave generation in a plasma-metamaterial composite, the intensity of which was much stronger than that in plasma with a similar level of electron density. We clarified that this specific intense second-harmonic-wave generation was derived from additional nonlinearity based on the electric connection between a plasma with a density gradient and metamaterials using an equivalent circuit model.

  20. Harmonic scalpel versus flexible CO2 laser for tongue resection: A histopathological analysis of thermal damage in human cadavers

    PubMed Central

    2011-01-01

    Background Monopolar cautery is the most commonly used surgical cutting and hemostatic tool for head and neck surgery. There are newer technologies that are being utilized with the goal of precise cutting, decreasing blood loss, reducing thermal damage, and allowing faster wound healing. Our study compares thermal damage caused by Harmonic scalpel and CO2 laser to cadaveric tongue. Methods Two fresh human cadaver heads were enrolled for the study. Oral tongue was exposed and incisions were made in the tongue akin to a tongue tumor resection using the harmonic scalpel and flexible C02 laser fiber at various settings recommended for surgery. The margins of resection were sampled, labeled, and sent for pathological analysis to assess depth of thermal damage calculated in millimeters. The pathologist was blinded to the surgical tool used. Control tongue tissue was also sent for comparison as a baseline for comparison. Results Three tongue samples were studied to assess depth of thermal damage by harmonic scalpel. The mean depth of thermal damage was 0.69 (range, 0.51 - 0.82). Five tongue samples were studied to assess depth of thermal damage by CO2 laser. The mean depth of thermal damage was 0.3 (range, 0.22 to 0.43). As expected, control samples showed 0 mm of thermal damage. There was a statistically significant difference between the depth of thermal injury to tongue resection margins by harmonic scalpel as compared to CO2 laser, (p = 0.003). Conclusion In a cadaveric model, flexible CO2 laser fiber causes less depth of thermal damage when compared with harmonic scalpel at settings utilized in our study. However, the relevance of this information in terms of wound healing, hemostasis, safety, cost-effectiveness, and surgical outcomes needs to be further studied in clinical settings. PMID:21806825

  1. Physical basis of critical analysis

    E-print Network

    Tsyganov, Y S

    2015-01-01

    A new approach to provide a fruitful analysis of signal amplitude is proposed. It is this method that has made it possible to eliminate some observed artificial events from the list of candidates for decays of superheavy nuclei. Examples of estimates of measured amplitudes of evaporation residues (EVR) are presented. Some attention is paid to a new hard statistical criterion for detecting rare events. This criterion can be applied in the case of significant role of random factors.

  2. Physical basis of critical analysis

    E-print Network

    Y. S. Tsyganov

    2015-06-08

    A new approach to provide a fruitful analysis of signal amplitude is proposed. It is this method that has made it possible to eliminate some observed artificial events from the list of candidates for decays of superheavy nuclei. Examples of estimates of measured amplitudes of evaporation residues (EVR) are presented. Some attention is paid to a new hard statistical criterion for detecting rare events. This criterion can be applied in the case of significant role of random factors.

  3. Analysis of the Double Output Induction Generator Using Direct Three-phase Model Part II - Harmonic Analysis

    Microsoft Academic Search

    Z. M. Salameh; L. F. Kazda

    1987-01-01

    This paper investigates the harmonic content of the rotor current, rotor voltage and the torque of the variable speed constant frequency double output induction generator (VSCF-DOIG). The waveforms of these variables were generated using a direct three-phase model and then analyzed numerically for their harmonic content using a Fourier series subroutine. In addition, this paper investigates the stator distortion currents

  4. Optical High Harmonic Generation in C60

    Microsoft Academic Search

    Guoping Zhang

    2005-01-01

    C60 et al. Physical Review Letters Physical Review B High harmonic generation (HHG) requires a strong laser field, but in a relatively weak laser field is sufficient. Numerical results presented here show while its low order harmonics result from the laser field, its high order ones are mainly from the multiple excitations. Since high order harmonics directly correlate electronic transitions,

  5. Present status of JADE's ??-physics analysis

    Microsoft Academic Search

    W. Bartel; D. Cord; P. Dittmann; R. Eichler; R. Felst; D. Haidt; S. Kawabata; H. Krehbiel; B. Naroska; L. O'Neill; J. Olsson; P. Steffen; W. Yen; E. Elsen; M. Helm; K. Meier; A. Peterson; G. Weber; H. Drum; J. Heintze; G. Heinzelmann; R. Heuer; J. von Krogh; P. Lennert; H. Matsumura; T. Nozaki; H. Rieseberg; A. Wagner; D. Darvill; F. Foster; G. Hughes; H. Wriedt; J. Allison; J. Armitage; A. Ball; I. Duerdoth; J. Hassard; F. Loebinger; H. McCann; B. King; A. Macbeth; H. Mills; P. Murphy; H. Prosper; K. Stephens; C. Clark; M. Goddard; R. Marshall; G. Pearce; M. Imori; T. Kobayashi; S. Komamiya; M. Koshiba; M. Minowa; S. Orito; A. Sato; T. Suda; H. Takeda; Y. Totsuka; Y. Watanabe; S. Yamada; C. Yanagisawa

    The present status of the -physics analysis performed by the JADE-Collaboration is reported. The reaction ee ee is observed at beam-energies of 6 GeV and 15 GeV, and it is compared with predictions from QED. The reaction ee ee + hadrons is observed at 15 GeV beam-energy. Several distributions of physical quantities are shown.

  6. Non-linear dynamic analysis of a multi-mesh gear train using multi-term harmonic balance method: sub-harmonic motions

    NASA Astrophysics Data System (ADS)

    Al-shyyab, A.; Kahraman, A.

    2005-01-01

    In this study, a non-linear time-varying dynamic model is used to investigate sub-harmonic and chaotic motions exhibited by a typical multi-mesh gear train. The purely torsional system is formed by three rigid shafts connected to each other by two spur gear pairs. The lumped parameter dynamic model includes both gear backlash clearances and parametric gear mesh stiffness fluctuations. Steady state period-one motions of the same system were studied in another by using a multi-term harmonic balance method in conjunction with discrete Fourier transforms. This study expands the same solution technique for an investigation of sub-harmonic resonances of the forced response. The accuracy of the predictions is demonstrated by comparing them to the direct numerical integration results. Effect of several system parameters such as alternating mesh stiffness amplitudes, gear mesh damping and static torque transmitted on sub-harmonic motions are described. It is shown that stable sub-harmonic motions mostly in the form of softening type resonances dictate the frequency ranges in which the period-one motions are unstable due to parametric excitations. Other non-linear phenomena including long sub-harmonic motions and period-doubling bifurcations leading to chaotic behavior are also predicted.

  7. High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis

    SciTech Connect

    Madsen, C. B.; Abu-samha, M.; Madsen, L. B. [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

    2010-04-15

    We present a generic approach for treating the effect of nuclear motion in high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors, which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH{sub 4} and CD{sub 4} and thereby provide direct theoretical support for a recent experiment [S. Baker et al., Science 312, 424 (2006)] that uses high-order harmonic generation to probe the ultrafast structural nuclear rearrangement of ionized methane.

  8. Analysis of the second harmonic generation of a femtosecond optical frequency comb

    NASA Astrophysics Data System (ADS)

    Wei, Dong; Aketagawa, Masato

    2014-12-01

    The second harmonic generation (SHG) of a femtosecond optical frequency comb (FOFC) has been studied. This work focuses on the SHG frequencies that are generated by the mixing of even-numbered frequency components from the original comb with odd-numbered components. It is observed that the generation of those frequencies is the reason the original FOFC and FOFC-based SHG signal have the same repetition frequency. The theoretical derivation agrees with the result of an optical experiment. Our results may be of use with the high-harmonic-generation process and FOFC-based SHG applications, including high-resolution spectroscopy, attosecond pulse generation, and precision length measurement.

  9. Symbolic Vector Analysis in Plasma Physics

    SciTech Connect

    Qin, H.; Tang, W.M.; Rewoldt, G.

    1997-10-09

    Many problems in plasma physics involve substantial amounts of analytical vector calculation. The complexity usually originates from both the vector operations themselves and the choice of underlying coordinate system. A computer algebra package for symbolic vector analysis in general coordinate systems, General Vector Analysis (GVA), is developed using Mathematica. The modern viewpoint for 3D vector calculus, differential forms on 3-manifolds, is adopted to unify and systematize the vector calculus operations in general coordinate systems. This package will benefit physicists and applied mathematicians in their research where complicated vector analysis is required. It will not only save a huge amount of human brain-power and dramatically improve accuracy, but this package will also be an intelligent tool to assist researchers in finding the right approaches to their problems. Several applications of this symbolic vector analysis package to plasma physics are also given.

  10. Mathematical physics and complex analysis. 4

    Microsoft Academic Search

    L. D. Faddeev

    1987-01-01

    This collection contains survey papers on investigations carried out at the Steklov Institute of Mathematics on partial differential equations, complex analysis, the spectral theory of functions, and mathematical physics, with particular emphasis on quantum field theory. Specific consideration is given to algebraic quantum field theory, the analytic properties of multiparticle amplitudes in axiomatic quantum field theory, the development of a

  11. A fault analysis of DC electric arc furnaces with SVC harmonic filters in a minimill plant

    Microsoft Academic Search

    Hansang Lee; Gilsoo Jang; Byungmoon Han

    2010-01-01

    This paper proposes the most feasible solution to overcome the failure of the 2nd harmonic filter in the static VAR compensator (SVC) which operates with the DC electric arc furnace (EAF) at Gwangyang Steel Mill in Korea. In order to investigate the causes of this failure, various measurements were carried out on the DC EAF and the main transformer at

  12. Harmonic balance device analysis of an LDMOS RF power amplifier with parasitics and matching network

    Microsoft Academic Search

    Francis M. Rotella; Zhiping Yu; Robert Dutton; Boris Troyanovsky; Gordon Ma

    1997-01-01

    This paper discusses a harmonic balance simulation involving a high power LDMOS device, bias circuitry and matching network. The paper begins with a discussion of the device and circuit configuration as well as the requirements for simulation. Next the paper describes the simulation algorithms and simulator structure in order to meet the requirements. PISCES is used as the basis and

  13. Vibration analysis considering higher harmonics of electromagnetic forces for rotating electric machines

    Microsoft Academic Search

    Shigeru SAKAMOTO; Tosuke HIRATA; Takashi KOBAYASHI; Kenzo KAJIWARA

    1999-01-01

    A method is described to calculate vibration due to electromagnetic forces for rotating electric machines. This method can calculate the frequency response of vibration due to higher harmonics of electromagnetic forces. The usefulness of this method is verified through the agreement between calculated and measured results for a three-phase\\/four-pole induction motor. The authors also calculate the complicated dynamic behavior caused

  14. Spherical Harmonic Analysis of Redshift Space Distortions in the IRAS PSCZ Redshift Survey

    Microsoft Academic Search

    H. Tadros; W. Ballinger; A. Heavens; A. Taylor; G. Efstathiou; W. Saunders; C. Frenk; O. Keeble; R. McMahon; S. Maddox; S. Oliver; M. Rowan-Robinson; W. Sutherland; S. White

    1998-01-01

    We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. Taking into account the first order distortion of the galaxy pattern due to redshift coordinates, we have measured the degree of distortion, parameterised by the distortion parameter beta ~ Omega^{0.6}\\/b, using maximum likelihood methods. We simultaneously measure either the undistorted amplitude

  15. Performance analysis of Z - source Inverter based ASD system with reduced harmonics

    Microsoft Academic Search

    Amitava Das; S. P. Chowdhury; A. Domijan

    2008-01-01

    This paper presents the Z - source inverter for adjustable speed drive system. The Z - source inverter employs a unique impedance network couple with inverter main circuit. By controlling the shoot through duty cycle, the Z - source inverter system using MOSFETS provide ride - through capability during voltage sags, reduces line harmonics, improves power factor and high reliability,

  16. Analysis of Pigmented Skin Lesion Border Irregularity Using the Harmonic Wavelet Transform

    Microsoft Academic Search

    Kathy Clawson; Philip Morrow; Bryan Scotney; John McKenna; Olivia Dolan

    2009-01-01

    The development of computerised systems which differentiate between suspicious tumours and clinically benign pigmented skin lesions can assist in improved early diagnosis of malignant melanoma, subsequently reducing mortality rates associated with this disease. One lesion feature indicative of malignancy is border irregularity. In this paper the theoretical fundamentals of a harmonic-wavelet based methodology for skin lesion border evaluation are described.

  17. Error and symmetry analysis of Misner's algorithm for spherical harmonic decomposition on a cubic grid

    E-print Network

    David R. Fiske

    2005-09-15

    Computing spherical harmonic decompositions is a ubiquitous technique that arises in a wide variety of disciplines and a large number of scientific codes. Because spherical harmonics are defined by integrals over spheres, however, one must perform some sort of interpolation in order to compute them when data is stored on a cubic lattice. Misner (2004, Class. Quant. Grav., 21, S243) presented a novel algorithm for computing the spherical harmonic components of data represented on a cubic grid, which has been found in real applications to be both efficient and robust to the presence of mesh refinement boundaries. At the same time, however, practical applications of the algorithm require knowledge of how the truncation errors of the algorithm depend on the various parameters in the algorithm. Based on analytic arguments and experience using the algorithm in real numerical simulations, I explore these dependencies and provide a rule of thumb for choosing the parameters based on the truncation errors of the underlying data. I also demonstrate that symmetries in the spherical harmonics themselves allow for an even more efficient implementation of the algorithm than was suggested by Misner in his original paper.

  18. Analysis of harmonic and off-band response of a dipole antenna

    Microsoft Academic Search

    K. P. Ray; G. V. Nikhare

    2003-01-01

    The off-band and harmonic response of a tuned cylindrical dipole antenna in terms of input impedance, VSWR, directivity and gain has been presented in this paper. The data can be used to estimate EMI levels radiated by the antenna at off-band frequencies.

  19. Harmonic perturbation theory for the analysis of boiling water reactor regional instabilities

    Microsoft Academic Search

    Thomas J. Downar; David A. Phegley

    1995-01-01

    The onset of regional instabilities in the Boiling Water Reactor has been directly related to the reactor subcritical reactivity. Because the calculation of higher harmonic modes for practical reactor problems is a significant computational expense, the research here investigated the application of perturbation methods to predict the subcritical reactivity. The method developed here is based on a second order perturbation

  20. Modeling Stretching Modes of Common Organic Molecules with the Quantum Mechanical Harmonic Oscillator: An Undergraduate Vibrational Spectroscopy Laboratory Exercise

    ERIC Educational Resources Information Center

    Parnis, J. Mark; Thompson, Matthew G. K.

    2004-01-01

    An introductory undergraduate physical organic chemistry exercise that introduces the harmonic oscillator's use in vibrational spectroscopy is developed. The analysis and modeling exercise begins with the students calculating the stretching modes of common organic molecules with the help of the quantum mechanical harmonic oscillator (QMHO) model.

  1. Direct extraction of quantitative structural information from x-ray fluorescence holograms using spherical-harmonic analysis

    NASA Astrophysics Data System (ADS)

    Wang, Yuhao; Bai, Jianming; Tyson, Trevor A.

    2012-06-01

    An x-ray fluorescence holograph contains information on both the amplitude and the phase of the x-ray scattering signal from a crystal structure. X-ray fluorescence holography is potentially a technique to directly extract atomic level structure information from crystal samples. We present here a reconstruction algorithm using a spherical-harmonic analysis that significantly improves the structure-resolving power of x-ray fluorescence holography over the widely used multiple energy Barton transform approach. Compared to the direct method for x-ray diffraction, this direct method has the advantages of full model independence and applicability to crystal systems with a large contrast in atomic numbers.

  2. Harmonic Generation

    Microsoft Academic Search

    H. J. Scott; L. J. Black

    1938-01-01

    When plate current in a vacuum-tube amplifier flows for only a portion of the grid-excitation cycle, harmonics appear in the output circuit. The magnitude of any one of these harmonics depends upon the fraction of the fundamental cycle during which plate current flows. In the gradual transition from perfect class A to extreme class C operation, the magnitude of the

  3. Tidal and residual currents in the Qiongzhou Strait estimated from shipboard ADCP data using a modified tidal harmonic analysis method

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-Hua; Ma, Yun-Long; Guo, Xinyu; Fan, Xiaopeng; Long, Yu; Yuan, Yaochu; Xuan, Ji-Liang; Huang, Daji

    2014-11-01

    In spring 2013, 33 repeat shipboard Acoustic Doppler Current Profile (ADCP) surveys were conducted to measure the tidal current in the Qiongzhou Strait (QS). The major tidal currents and the residual current along a section across the QS were estimated using a modified tidal harmonic analysis method based on the inverse technique. A simple simulation and comparisons with previous observations demonstrated that the tidal currents estimated using the modified tidal harmonic analysis method are reasonable, and this method was able to control the magnitude and deviation of the estimation error. The direction of the major axis of tidal current ellipses is generally along the strait. Diurnal tidal constituents are dominant among the five tidal current constituents (K1, O1, M2, S2, and MSf). The ratio of the amplitudes of O1, K1, M2, S2, and MSf, averaged along the section across the QS is 1:0.79:0.42:0.27:0.29. The residual current along the entire section is all westward; the averaged velocity over the section is 6.0±2.1 cm s-1; the associated volume transport through the section is -0.065 ± 0.046 Sv (Sv = 106 × m3 s-1), in which the second value denotes the uncertainty of first value. Dynamic analysis indicates that tidal current activity is more dominant than mean current and eddy activity, and tidal rectification and sea level difference between two entrances of the QS are important in maintaining the residual current through the strait.

  4. M-shaped asymmetric nonlinear oscillator for broadband vibration energy harvesting: Harmonic balance analysis and experimental validation

    NASA Astrophysics Data System (ADS)

    Leadenham, S.; Erturk, A.

    2014-11-01

    Over the past few years, nonlinear oscillators have been given growing attention due to their ability to enhance the performance of energy harvesting devices by increasing the frequency bandwidth. Duffing oscillators are a type of nonlinear oscillator characterized by a symmetric hardening or softening cubic restoring force. In order to realize the cubic nonlinearity in a cantilever at reasonable excitation levels, often an external magnetic field or mechanical load is imposed, since the inherent geometric nonlinearity would otherwise require impractically high excitation levels to be pronounced. As an alternative to magnetoelastic structures and other complex forms of symmetric Duffing oscillators, an M-shaped nonlinear bent beam with clamped end conditions is presented and investigated for bandwidth enhancement under base excitation. The proposed M-shaped oscillator made of spring steel is very easy to fabricate as it does not require extra discrete components to assemble, and furthermore, its asymmetric nonlinear behavior can be pronounced yielding broadband behavior under low excitation levels. For a prototype configuration, linear and nonlinear system parameters extracted from experiments are used to develop a lumped-parameter mathematical model. Quadratic damping is included in the model to account for nonlinear dissipative effects. A multi-term harmonic balance solution is obtained to study the effects of higher harmonics and a constant term. A single-term closed-form frequency response equation is also extracted and compared with the multi-term harmonic balance solution. It is observed that the single-term solution overestimates the frequency of upper saddle-node bifurcation point and underestimates the response magnitude in the large response branch. Multi-term solutions can be as accurate as time-domain solutions, with the advantage of significantly reduced computation time. Overall, substantial bandwidth enhancement with increasing base excitation is validated experimentally, analytically, and numerically. As compared to the 3 dB bandwidth of the corresponding linear system with the same linear damping ratio, the M-shaped oscillator offers 3200, 5600, and 8900 percent bandwidth enhancement at the root-mean-square base excitation levels of 0.03g, 0.05g, and 0.07g, respectively. The M-shaped configuration can easily be exploited in piezoelectric and electromagnetic energy harvesting as well as their hybrid combinations due to the existence of both large strain and kinetic energy regions. A demonstrative case study is given for electromagnetic energy harvesting, revealing the importance of higher harmonics and the need for multi-term harmonic balance analysis for predicting the electrical power output accurately.

  5. Temporal variations in low degree zonal harmonics from Starlette orbit analysis

    NASA Technical Reports Server (NTRS)

    Cheng, M. K.; Eanes, R. J.; Shum, C. K.; Schutz, B. E.; Tapley, B. D.

    1989-01-01

    The dynamical effect of temporal variations in the zonal harmonics of the earth's gravitational potential due to tidal and meteorological mass redistribution has been observed using satellite laser ranging (SLR) measurements to Starlette. The secular variations in the Earth's zonal harmonics and the year-to-year fluctuation of the even degree annual and semi-annual tides, S(a) and S(sa) have been determined from a continuous Starlette orbit spanning from 1983 through 1985. The mean values for S(a) and S(sa) tides are in good agreement with other tide solutions. The year-to-year fluctuations of the even degree S(a), deduced from Starlette node variations, are about 25 percent of the mean value obtained during the three-year Starlette orbit span.

  6. A microcontroller-based soft-starter for residential air-conditioners: harmonic analysis

    Microsoft Academic Search

    S. El Ferik; C. B. Ahmed; L. Ben Amor; S. A. Hussain

    2008-01-01

    Purpose – The purpose of this paper is to reduce the inrush current and dip in voltage for energy- saving purposes in relation to residential air-conditioning systems. Design\\/methodology\\/approach – The paper focuses on the experimental harmonic investigation of a window-type residential AC unit line current under time-based soft-starting control strategy. The control strategy assumes that only source voltage and current

  7. 3D quantitative Fourier analysis of second harmonic generation microscopy images of collagen structure in cartilage

    NASA Astrophysics Data System (ADS)

    Romijn, Elisabeth I.; Lilledahl, Magnus B.

    2013-02-01

    One of the main advantages of nonlinear microscopy is that it provides 3D imaging capability. Second harmonic generation is widely used to image the 3D structure of collagen fibers, and several works have highlighted the modification of the collagen fiber fabric in important diseases. By using an ellipsoidal specific fitting technique on the Fourier transformed image, we show, using both synthetic images and SHG images from cartilage, that the 3D direction of the collagen fibers can be robustly determined.

  8. FAST TRACK COMMUNICATION: Molecular high-order harmonic generation: analysis of a destructive interference condition

    NASA Astrophysics Data System (ADS)

    Odžak, S.; Miloševi?, D. B.

    2009-04-01

    The multiple-slit type destructive interference in molecular high-order harmonic generation (HHG) leads to the minima in the harmonic yield for particular molecular orientation angle ?L and the harmonic order n. For the case of homonuclear diatomic molecules, we have found a condition for this destructive interference in the form of a nonlinear equation over n and ?L. This condition strongly depends on the molecular symmetry, on the atomic orbitals of which a particular highest occupied molecular orbital (HOMO) consists and on the internuclear distance R. Therefore, one can learn about the molecular structure and dynamics analysing the HHG spectra of aligned molecules. Using the example of an Ar2 molecule, having 5?u HOMO, for various internuclear distances, we analyse this interference condition and show that, in the (n, ?L) plane, it manifests in the form of one or several continuous curves. Furthermore, in the (Rcos ?L, ?min) plane, where ?min is an effective de Broglie wavelength of the recombining electron, this condition leads to a set of lines which are positioned between the limiting cases of molecular orbitals consisting of only one type (even or odd) of atomic orbitals (s and p in the Ar2 case).

  9. Harmonic behaviour of HVDC cables

    Microsoft Academic Search

    Roberto Benato; Michele Forzan; Marco Marelli; Ambrogio Orini; Ernesto Zaccone

    2010-01-01

    The paper deals with harmonic analysis of HVDC submarine cables. The longitudinal series impedance matrix is computed with reference to armoured cables. The results are also compared with Finite Element models showing a very good agreement. This investigation can be considered the first step of more detailed further analysis about the propagation of harmonics on the d.c. and a.c. sides.

  10. Time-Symmetric Discretization of The Harmonic Oscillator

    SciTech Connect

    Antippa, Adel F. [Departement de Physique Universite du Quebec a Trois-Rivieres Trois-Rivieres, Quebec, G9A 5H7 (Canada); Dubois, Daniel M. [Centre for Hyperincursion and Anticipation in Ordered Systems, CHAOS asbl, Institute of Mathematics, B37, University of Liege Grande Traverse 12, B-4000 LIEGE 1 (Belgium)

    2010-11-24

    We explicitly and analytically demonstrate that simple time-symmetric discretization of the harmonic oscillator (used as a simple model of a discrete dynamical system), leads to discrete equations of motion whose solutions are perfectly stable at all time scales, and whose energy is exactly conserved. This result is important for both fundamental discrete physics, as well as for numerical analysis and simulation.

  11. Analysis and projections of physics in Chile

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo; Zambra, Marcelo; Loewe, Marcelo; Gutiérrez, Gonzalo; Molina, Mario; Barra, Felipe; Lund, Fernando; Saavedra, Carlos; Haberle, Patricio

    2008-11-01

    In the present work, an assessment of the Physics research capacity in Chile is presented. For this, the period between 2000 and June 2005 has been studied. In this period almost 200 physicists have contributed to scientific production in terms of ISI publications. Amongst these 200, ~160 correspond to theoretical physicists and only ~40 to experimental physicists; ~178 are men and only ~22 are women. A more detailed analysis shows that ~160 physicists have at least one appearance in ISI publications per year considering the last 3 years. Ten years ago, a similar criteria (at least one appearance per year in ISI articles, considering mobile three-year periods), the number of active physicists in the Chilean community was estimated at 70. Therefore, the Chilean active physicists' community has doubled in 10 years. There exist 20 centres in which scientific research is developed: 18 university centres, a government institute and a private institute. As regards scientific productivity, both as related to disciplines or research areas, and well as in relation to research centres, it is found that, generally, scientific production, in a particular area in Physics or in a research centre, is directly related to the number of corresponding researchers; that is to say, the percentage of the national productivity in an area or research centre corresponds to its share in the total number of physicists in the country. A geographical analysis shows that 50% of the productivity corresponds to Santiago and 50% to the rest of the country. The impact of the different funds for research is assessed, also: FONDECYT, Presidential Chairs and large projects and centres of excellence. According to Physics researchers opinion, Fondo Nacional de Ciencia y Tecnología (FONDECYT, National Fund fro Science and Technology) has become the best instrument to support researchi activities in Chile. However, the amount of projects awarded has practically not been increased, which is insufficient for a community that has doubled. Likewise, even 50% of the productivity corresponds to regional centres, only 35% of projects coming from FONDECYT are awarded to the regions (away from the metropolitan region). Regarding experimental Physics, this represents 20% of the community in both, researchers and productivity of the community. However, in the regular FONDECYT contest in 2005, only 2 projects (10%) were awarded in experimental Physics, which is undoubtedly insufficient. The study also includes a brief analysis according to social appraisal of Physics, dissemination activities to other areas of national living, and relation of Physics with the productive sector. Finally, some recommendations are made: - To create a special fund for experimental Physics in the regular FONDECYT contest. Complementarily, experimental Physics should be one of the priority areas for the technological and scientific development of the country. - To duplicate the amount assigned to Physics in the regular FONDECYT contest. - To create a system that allows increasing the salaries of the researchers in Physics so they could be assimilated to other professional salaries in our country or at an international level. Not only demands must be globalized but also the benefits.

  12. BESIU Physical Analysis on Hadoop Platform

    NASA Astrophysics Data System (ADS)

    Huo, Jing; Zang, Dongsong; Lei, Xiaofeng; Li, Qiang; Sun, Gongxing

    2014-06-01

    In the past 20 years, computing cluster has been widely used for High Energy Physics data processing. The jobs running on the traditional cluster with a Data-to-Computing structure, have to read large volumes of data via the network to the computing nodes for analysis, thereby making the I/O latency become a bottleneck of the whole system. The new distributed computing technology based on the MapReduce programming model has many advantages, such as high concurrency, high scalability and high fault tolerance, and it can benefit us in dealing with Big Data. This paper brings the idea of using MapReduce model to do BESIII physical analysis, and presents a new data analysis system structure based on Hadoop platform, which not only greatly improve the efficiency of data analysis, but also reduces the cost of system building. Moreover, this paper establishes an event pre-selection system based on the event level metadata(TAGs) database to optimize the data analyzing procedure.

  13. Error analysis of the density-matrix renormalization group algorithm for a chain of harmonic oscillators

    E-print Network

    Yongjun Ma; Jiaxiang Wang; Xinye Xu; Qi Wei; Sabre Kais

    2014-05-10

    We investigate the application of the density-matrix renormalization group (DMRG) algorithm to a one-dimensional harmonic oscillator chain and compare the results with exact solutions, aiming to improve the algorithm efficiency. It has been demonstrated that the algorithm can give quite accurate results if the procedure is proper organized, for example, by using the optimized bases. The errors of calculated ground state energy and the energy gap between the ground state and the first excited state are analyzed, which are found to be critically dependent upon the size of the system or the energy level structure of the studied system and the number of states targeted during the DMRG procedure.

  14. Analysis of the formation and interaction of solitons in nonlinear transmission lines by means of a harmonic balance technique

    Microsoft Academic Search

    I. Molina-Fernandez; C. Camacho-Peiialosa; J. I. Ramos

    1991-01-01

    A harmonic balance technique is used to study the formation and interaction of solitons in discrete, lossless, nonlinear transmission lines as a function of the number of harmonics, number of LC-cells, and pulse height and width at the generator. It is shown that the number of harmonics required to accurately determine the soliton formation and propagation increases as the generator's

  15. Physics research in Israel—A preliminary bibliometric analysis

    Microsoft Academic Search

    Subbiah Arunachalam; M. K. Dhirendra Rao; Praveen K. Shrivastava

    1984-01-01

    The impact of physics research carried out in Israel on the international literature is assessed from data on publication and citation counts. We have considered in this analysis all papers published from Israel and covered under six of the ten major sections of INSPEC's Physics Abstracts, January-June 1977 (covering condensed matter physics, nuclear and particle physics, atomic and molecular physics

  16. Non-linear dynamic analysis of a multi-mesh gear train using multi-term harmonic balance method: sub-harmonic motions

    Microsoft Academic Search

    A. Al-Shyyab; A. Kahraman

    2005-01-01

    In this study, a non-linear time-varying dynamic model is used to investigate sub-harmonic and chaotic motions exhibited by a typical multi-mesh gear train. The purely torsional system is formed by three rigid shafts connected to each other by two spur gear pairs. The lumped parameter dynamic model includes both gear backlash clearances and parametric gear mesh stiffness fluctuations. Steady state

  17. Gender and Physics: a Theoretical Analysis

    NASA Astrophysics Data System (ADS)

    Rolin, Kristina

    This article argues that the objections raised by Koertge (1998), Gross and Levitt (1994), and Weinberg (1996) against feminist scholarship on gender and physics are unwarranted. The objections are that feminist science studies perpetuate gender stereotypes, are irrelevant to the content of physics, or promote epistemic relativism. In the first part of this article I argue that the concept of gender, as it has been developed in feminist theory, is a key to understanding why the first objection is misguided. Instead of reinforcing gender stereotypes, feminist science studies scholars can formulate empirically testable hypotheses regarding local and contested beliefs about gender. In the second part of this article I argue that a social analysis of scientific knowledge is a key to understanding why the second and the third objections are misguided. The concept of gender is relevant for understanding the social practice of physics, and the social practice of physics can be of epistemic importance. Instead of advancing epistemic relativism, feminist science studies scholars can make important contributions to a subfield of philosophy called social epistemology.

  18. A study of the application of power-spectral methods of generalized harmonic analysis to gust loads on airplanes

    NASA Technical Reports Server (NTRS)

    Press, Harry; Mazelsky, Bernard

    1954-01-01

    The applicability of some results from the theory of generalized harmonic analysis (or power-spectral analysis) to the analysis of gust loads on airplanes in continuous rough air is examined. The general relations for linear systems between power spectrums of a random input disturbance and an output response are used to relate the spectrum of airplane load in rough air to the spectrum of atmospheric gust velocity. The power spectrum of loads is shown to provide a measure of the load intensity in terms of the standard deviation (root mean square) of the load distribution for an airplane in flight through continuous rough air. For the case of a load output having a normal distribution, which appears from experimental evidence to apply to homogeneous rough air, the standard deviation is shown to describe the probability distribution of loads or the proportion of total time that the load has given values. Thus, for airplane in flight through homogeneous rough air, the probability distribution of loads may be determined from a power-spectral analysis. In order to illustrate the application of power-spectral analysis to gust-load analysis and to obtain an insight into the relations between loads and airplane gust-response characteristics, two selected series of calculations are presented. The results indicate that both methods of analysis yield results that are consistent to a first approximation.

  19. Harmonic analysis of the AC magnetic response on directionally solidified YBaCuO samples

    SciTech Connect

    Polichetti, M.; Pace, S.; Vecchione, A. [Univ. of Salerno-INFM, Baronissi (Italy). Dept. of Physics] [Univ. of Salerno-INFM, Baronissi (Italy). Dept. of Physics

    1999-04-20

    The transport properties and the dynamics of the flux lines have been investigated on YBaCuO melt textured by measuring the AC susceptibility harmonics as function of the temperature, at different frequencies and amplitudes of the AC magnetic field. The interpretation of the behavior of the experimental curves has been done by their comparison with the results obtained by critical state pictures and by simulations of the diffusion processes of the magnetic field which determine the AC response in presence of different regimes of flux dynamics. The temperature dependencies of the third harmonics of the AC susceptibility at different frequencies have been used in particular to determine what is the flux dynamic regime governing the magnetic response of melt textured samples in the different experimental conditions. A good qualitative agreement has been found between the experimental curves and the ones simulated by assuming that dissipation processes are a sequence of independent flux creep and flux flow events within a collective pinning framework.

  20. Theoretical analysis of dynamic chemical imaging with lasers using high-order harmonic generation

    SciTech Connect

    Van-Hoang Le [J. R. Macdonald Laboratory, Department of Physics, Cardwell Hall, Kansas State University, Manhattan, Kansas 66506 (United States); Department of Physics, University of Pedagogy, 280 An Duong Vuong, Ward 5, Ho Chi Minh City (Viet Nam); Anh-Thu Le; Xie Ruihua; Lin, C. D. [J. R. Macdonald Laboratory, Department of Physics, Cardwell Hall, Kansas State University, Manhattan, Kansas 66506 (United States)

    2007-07-15

    We report theoretical investigations of the tomographic procedure suggested by Itatani et al. [Nature (London) 432, 867 (2004)] for reconstructing highest occupied molecular orbitals (HOMOs) using high-order harmonic generation (HHG). Due to the limited range of harmonics from the plateau region, we found that even under the most favorable assumptions, it is still very difficult to obtain accurate HOMO wave functions using the tomographic procedure, but the symmetry of the HOMOs and the internuclear separation between the atoms can be accurately extracted, especially when lasers of longer wavelengths are used to generate the HHG. Since the tomographic procedure relies on approximating the continuum wave functions in the recombination process by plane waves, the method can no longer be applied upon the improvement of the theory. For future chemical imaging with lasers, we suggest that one may want to focus on how to extract the positions of atoms in molecules instead, by developing an iterative method such that the theoretically calculated macroscopic HHG spectra can best fit the experimental HHG data.

  1. Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

    PubMed

    Lin, Bihong; Chen, Jincan

    2003-11-01

    An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle. PMID:14682856

  2. Photonic band structure in one-dimensional nonlinear crystal: Analysis of harmonic stability

    NASA Astrophysics Data System (ADS)

    Avendaño, Carlos G.; Reyes, J. Adrián

    2015-01-01

    We consider a one-dimensional nonlinear photonic crystal consisting of an infinite set of concentrated equidistant scatterers inserted in a linear dielectric medium. Each of the scatterers is made by a very thin layer of a nonlinear medium with high refractive index that we model by a delta function. We show that the nonlinear optical exact solutions of this system form an intensity dependent band structure. To analyze the stability of these solutions we consider a modulation harmonic perturbation of these solutions whose amplitudes are slightly above the instability threshold. We demonstrate that the nonlinearity gives rise to an oscillatory instability of the solutions, which is a localized version of the well-known modulational instability of the nonlinear Schrodinger equation. We show that the linear harmonic perturbation forms as well a band structure whose allowed bands coincide for some intervals with those of the nonlinear band structure of the solutions for which case the structures are unstable whereas in the region where both the linear and nonlinear bands do not coincide, the nonlinear waves are indeed stable so that they conform spatial solitons.

  3. Autoregressive harmonic analysis of the earth's polar motion using homogeneous International Latitude Service data

    NASA Technical Reports Server (NTRS)

    Chao, B. F.

    1983-01-01

    The homogeneous set of 80-year-long (1900-1979) International Latitude Service (ILS) polar motion data is analyzed using the autoregressive method (Chao and Gilbert, 1980), which resolves and produces estimates for the complex frequency (or frequency and Q) and complex amplitude (or amplitude and phase) of each harmonic component in the data. The ILS data support the multiple-component hypothesis of the Chandler wobble. It is found that the Chandler wobble can be adequately modeled as a linear combination of four (coherent) harmonic components, each of which represents a steady, nearly circular, prograde motion. The four-component Chandler wobble model 'explains' the apparent phase reversal during 1920-1940 and the pre-1950 empirical period-amplitude relation. The annual wobble is shown to be rather stationary over the years both in amplitude and in phase, and no evidence is found to support the large variations reported by earlier investigations. The Markowitz wobble is found to be marginally retrograde and appears to have a complicated behavior which cannot be resolved because of the shortness of the data set.

  4. Spherical harmonics analysis of Fermi gamma-ray data and the Galactic dark matter halo

    E-print Network

    Dmitry Malyshev; Jo Bovy; Ilias Cholis

    2011-08-09

    We argue that the decomposition of gamma-ray maps in spherical harmonics is a sensitive tool to study dark matter (DM) annihilation or decay in the main Galactic halo of the Milky Way. Using the spherical harmonic decomposition in a window excluding the Galactic plane, we show for one year of Fermi data that adding a spherical template (such as a line-of-sight DM annihilation profile) to an astrophysical background significantly reduces chi^2 of the fit to the data. In some energy bins the significance of this DM-like fraction is above three sigma. This can be viewed as a hint of DM annihilation signal, although astrophysical sources cannot be ruled out at this moment. We use the derived DM fraction as a conservative upper limit on DM annihilation signal. In the case of bb-bar annihilation channel the limits are about a factor of two less constraining than the limits from dwarf galaxies. The uncertainty of our method is dominated by systematics related to modeling the astrophysical background. We show that with one year of Fermi data the statistical sensitivity would be sufficient to detect DM annihilation with thermal freeze out cross section for masses below 100 GeV.

  5. Analysis and measurement of the modulation transfer function of harmonic shear wave induced phase encoding imaging

    PubMed Central

    McAleavey, Stephen A.

    2014-01-01

    Shear wave induced phase encoding (SWIPE) imaging generates ultrasound backscatter images of tissue-like elastic materials by using traveling shear waves to encode the lateral position of the scatters in the phase of the received echo. In contrast to conventional ultrasound B-scan imaging, SWIPE offers the potential advantages of image formation without beam focusing or steering from a single transducer element, lateral resolution independent of aperture size, and the potential to achieve relatively high lateral resolution with low frequency ultrasound. Here a Fourier series description of the phase modulated echo signal is developed, demonstrating that echo harmonics at multiples of the shear wave frequency reveal target k-space data at identical multiples of the shear wavenumber. Modulation transfer functions of SWIPE imaging systems are calculated for maximum shear wave acceleration and maximum shear constraints, and compared with a conventionally focused aperture. The relative signal-to-noise ratio of the SWIPE method versus a conventionally focused aperture is found through these calculations. Reconstructions of wire targets in a gelatin phantom using 1 and 3.5?MHz ultrasound and a cylindrical shear wave source are presented, generated from the fundamental and second harmonic of the shear wave modulation frequency, demonstrating weak dependence of lateral resolution with ultrasound frequency. PMID:24815265

  6. Spherical Harmonic Transform Algorithms

    SciTech Connect

    Drake, John B [ORNL; Worley, Patrick H [ORNL; D'Azevedo, Eduardo [ORNL

    2008-01-01

    A collection of MATLAB classes for computing spherical harmonic transforms are presented and used to solve simple partial differential equations on the sphere. The spectral synthesis and analysis using fast Fourier transforms and Legendre transforms with the associated Legendre functions are presented in depth. A set of methods associated with a spectral\\_field class provides spectral approximation to the $\\DIV$, $\\CURL$, $\\GRAD$, and $\\LAPL$ in spherical geometr y. Laplace inversion and Helmholtz equation solvers are also methods for this clas s. Investigation of algorithms and analysis for spherical harmonic transform optio ns for parallel high performance computers are discussed in the context of global climate and weather models.

  7. Parameter analysis for a high-gain harmonic generation FEL using a recently developed 3D polychromatic code.

    SciTech Connect

    Biedron, S. G.; Freund, H. P.; Yu, L.-H.

    1999-09-10

    One possible design for a fourth-generation light source is the high-gain harmonic generation (HGHG) free-electron laser (FEL). Here, a coherent seed with a wavelength at a subharmonic of the desired output radiation interacts with the electron beam in an energy-modulating section. This energy modulation is then converted into spatial bunching while traversing a dispersive section (a three-dipole chicane). The final step is passage through a radiative section, an undulator tuned to the desired higher harmonic output wavelength. The coherent seed serves to remove noise and can be at a much lower subharmonic of the output radiation, thus eliminating the concerns found in self-amplified spontaneous emission (SASE) and seeded FELs, respectively. Recently, a 3D code that includes multiple frequencies, multiple undulatory (both in quantity and/or type), quadruple magnets, and dipole magnets was developed to easily simulate HGHG. Here, a brief review of the HGHG theory, the code development, the Accelerator Test Facility's (ATF) HGHG FEL experimental parameters, and the parameter analysis from simulations of this specific experiment will be discussed.

  8. Lunar physical librations and laser ranging

    Microsoft Academic Search

    J. G. Williams; M. A. Slade; D. H. Eckhardt; W. M. Kaula

    1973-01-01

    The analysis of lunar laser ranging data requires very accurate calculations of the lunar physical librations. Libration terms are given which arise from the additive and planetary terms in the lunar theory. The large size of the recently discovered terms due to third degree gravitational harmonics will allow some of these harmonics to be measured, in addition toß and?, by

  9. Analysis of collagen fiber domain organization by Fourier second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Ghazaryan, Ara; Tsai, Halley F.; Hayrapetyan, Gor; Chen, Wei-Liang; Chen, Yang-Fang; Jeong, Myung Yung; Kim, Chang-Seok; Chen, Shean-Jen; Dong, Chen-Yuan

    2013-03-01

    We present an automated and systematic two-dimensional discrete Fourier transform (2D-FFT) approach to analyze collagen fiber organization through the use of second harmonic generation (SHG) microscopy. Average orientations of individual domains and Ising-like order parameters introduced to characterize the correlation between orientations of adjacent domains may be used to quantitatively characterize fibrous tissues. Our approach was applied to analyze tissues including rat tail tendon, mouse skin, bovine corneas, and human corneas. We also show that collagen fiber organization in normal and keratokonus human corneas may be distinguished. The current approach may be used for the quantitative differentiation of SHG collagen fiber morphology in different tissues and may be applied for diagnostic purposes.

  10. A Fiber Approach to Harmonic Analysis of Unfolded Higher-Spin Field Equations

    E-print Network

    Carlo Iazeolla; Per Sundell

    2008-09-01

    In Vasiliev's unfolded formulation of higher-spin dynamics the standard fields are embedded on-shell into covariantly constant master fields valued in Lorentz-covariant slices of the star-product algebra A of functions on the singleton phase space. Correspondingly, the harmonic expansion is taken over compact slices of A that are unitarizable in a rescaled trace-norm rather than the standard Killing norm. Motivated by the higher-derivative nature of the theory, we examine indecomposable unitarizable Harish-Chandra modules consisting of standard massless particles plus linearized runaway solutions. This extension arises naturally in the above fiber approach upon realizing compact-weight states as non-polynomial analytic functions in A.

  11. Quaternionic Analysis, Representation Theory and Physics

    E-print Network

    Igor Frenkel; Matvei Libine

    2011-07-22

    We develop quaternionic analysis using as a guiding principle representation theory of various real forms of the conformal group. We first review the Cauchy-Fueter and Poisson formulas and explain their representation theoretic meaning. The requirement of unitarity of representations leads us to the extensions of these formulas in the Minkowski space, which can be viewed as another real form of quaternions. Representation theory also suggests a quaternionic version of the Cauchy formula for the second order pole. Remarkably, the derivative appearing in the complex case is replaced by the Maxwell equations in the quaternionic counterpart. We also uncover the connection between quaternionic analysis and various structures in quantum mechanics and quantum field theory, such as the spectrum of the hydrogen atom, polarization of vacuum, one-loop Feynman integrals. We also make some further conjectures. The main goal of this and our subsequent paper is to revive quaternionic analysis and to show profound relations between quaternionic analysis, representation theory and four-dimensional physics.

  12. Analysis of open loop higher harmonic control at high airspeeds on a modern four-bladed articulated rotor

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi; Leyland, Jane

    1992-01-01

    The effects of open loop higher harmonic control (HHC) on rotor hub loads, performance, and push rod loads of a Sikorsky S-76 helicopter rotor at high airspeeds (up to 200 knots) and moderate lift (10,000 lbs) were studied analytically. The present analysis was performed as a part of a wind tunnel pre-test prediction and preparation procedure, as well as to provide analytical results for post-test correlation efforts. The test associated with this study is to be concluded in the 40- by 80-Foot Wind Tunnel of the National Full-Scale Aerodynamics Complex (NFAC) at the NASA Ames Research Center. The results from this analytical study show that benefits from HHC can be achieved at high airspeeds. These results clear the way for conducting (with the requirement of safe pushrod loads) an open loop HHC test at high airspeeds in the 40- by 80-Foot Wind Tunnel using an S-76 rotor as the test article.

  13. Analysis of open loop higher harmonic control at high airspeeds on a modern four-bladed articulated rotor

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi; Leyland, Jane

    1991-01-01

    The effects of open loop higher harmonic control (HHC) on rotor hub loads, performance, and push rod loads of a Sikorsky S-76 helicopter rotor at high airspeeds (up to 200 knots) and moderate lift (10,000 lbs) were studied analytically. The analysis was performed as part of a wind tunnel pre-test prediction and preparation procedure, as well as to provide analytical results for post-test correlation efforts. The test associated with this study is to be concluded in the 40- by 80-Foot Wind Tunnel of the National Full-Scale Aerodynamics Complex (NFAC) at the NASA Ames Research Center. The results from this analytical study show that benefits from HHC can be achieved at high airspeeds. These results clear the way for conducting (with the requirement of safe pushrod loads) an open loop HHC test a high airspeeds in the 40- by 80-Foot Wind Tunnel using an S-76 rotor as the test article.

  14. Harmonic analysis approach to the 'TunneLadder' - A modified Karp circuit for millimeter-wave TWTA's

    NASA Technical Reports Server (NTRS)

    Kosmahl, H. G.; Palmer, R. W.

    1982-01-01

    A field approach to the summed harmonic analysis of the TunneLadder structure, or modified forward-wave Karp circuit, is developed by combining TM(01) and TE(11) modes. Results suggest the suitability of this structure as a high-impedance, about 1-% bandwidth circuit, millimeter-wave forward-wave-type amplifier that is voltage tunable over about a 5-% frequency range and has excellent power handling ability. Theory gives good agreement with experimental results obtained by Karp in omega-beta dispersion and predicts qualitatively the appearances of the antisymmetric mode discussed and of the so called Hightron mode that was discussed earlier in White, Enderby and Birdsall (1964), and Enderby (1964), in addition to the desired symmetric mode.

  15. Review of Wavelet Theory and Harmonic Analysis in Applied Sciences, C.E. D'Atellis and E.M. Fernandez-Berdaguer, Ed.

    E-print Network

    Kon, Mark

    Review of Wavelet Theory and Harmonic Analysis in Applied Sciences, C.E. D'Atellis and E.M. Fernandez-Berdaguer, Ed. Mark A. Kon, Boston University Wavelet theory has had a far-reaching influence, not only on the theory of wavelets, but on their applications in almost every area of science which has

  16. Harmonic analysis of the Earth's gravitational field by means of semi-continuous ephemerides of a low Earth orbiting GPS-tracked satellite. Case study: CHAMP

    Microsoft Academic Search

    T. Reubelt; G. Austen; E. W. Grafarend

    2003-01-01

    An algorithm for the determination of the spherical harmonic coefficients of the terrestrial gravitational field representation from the analysis of a kinematic orbit solution of a low earth orbiting GPS-tracked satellite is presented and examined. A gain in accuracy is expected since the kinematic orbit of a LEO satellite can nowadays be determined with very high precision, in the range

  17. An Introduction of Infinity Harmonic Changyou Wang

    E-print Network

    Wang, Changyou

    An Introduction of Infinity Harmonic Functions Changyou Wang University of Kentucky Lexington, KY on the analysis of infinity harmonic functions, a subject that has received considerable interests very recently characterizations of infinity harmonic functions. He presents the celebrated theorem by R. Jensen [17

  18. Molecular structure, Normal Coordinate Analysis, harmonic vibrational frequencies, Natural Bond Orbital, TD-DFT calculations and biological activity analysis of antioxidant drug 7-hydroxycoumarin

    NASA Astrophysics Data System (ADS)

    Sebastian, S.; Sylvestre, S.; Jayarajan, D.; Amalanathan, M.; Oudayakumar, K.; Gnanapoongothai, T.; Jayavarthanan, T.

    2013-01-01

    In this work, we report harmonic vibrational frequencies, molecular structure, NBO and HOMO, LUMO analysis of Umbelliferone also known as 7-hydroxycoumarin (7HC). The optimized geometric bond lengths and bond angles obtained by computation (monomer and dimmer) shows good agreement with experimental XRD data. Harmonic frequencies of 7HC were determined and analyzed by DFT utilizing 6-311+G(d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of Normal Coordinate Analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). The change in electron density (ED) in the ?* and ?* antibonding orbitals and stabilization energies E(2) have been calculated by Natural Bond Orbital (NBO) analysis to give clear evidence of stabilization originating in the hyperconjugation of hydrogen-bonded interaction. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincides with the experimental spectra. Microbial activity of studied compounds was tested against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Psuedomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Shigella flexneri, Salmonella typhi and Enterococcus faecalis.

  19. Full sky harmonic analysis hints at large ultra-high energy cosmic ray deflections

    NASA Astrophysics Data System (ADS)

    Tinyakov, P. G.; Urban, F. R.

    2015-03-01

    The full-sky multipole coefficients of the ultra-high energy cosmic ray (UHECR) flux have been measured for the first time by the Pierre Auger and Telescope Array collaborations using a joint data set with E > 10 EeV. We calculate these harmonic coefficients in the model where UHECR are protons and sources trace the local matter distribution, and compare our results with observations. We find that the expected power for low multipoles (dipole and quadrupole, in particular) is sytematically higher than in the data: the observed flux is too isotropic. We then investigate to which degree our predictions are influenced by UHECR deflections in the regular Galactic magnetic field. It turns out that the UHECR power spectrum coefficients C l are quite insensitive to the effects of the Galactic magnetic field, so it is unlikely that the discordance can be reconciled by tuning the Galactic magnetic field model. On the contrary, a sizeable fraction of uniformly distributed flux (representing for instance an admixture of heavy nuclei with considerably larger deflections) can bring simulations and observations to an accord.

  20. Does well-harmonized homeostasis exist in heart rate fluctuations? Time series analysis and model simulations.

    PubMed

    Shiau, Yuo-Hsien

    2009-03-12

    Analyzing heart rate variability from electrocardiographic recordings has been an important method for assessing cardiovascular autonomic regulation. Researchers have conducted extensive analyses on normal as well as pathological hearts, however, it is still unclear whether increasing or decreasing the complexity of heart rate variability is a characteristic of healthy systems. In this study, we find the existence of well-harmonized homeostasis in heart rate fluctuations, in particular, the evidence is verified among different individuals including healthy subjects, ICU patients, and one child with brainstem dysfunction. The methodology we used is composed of two parts, in which one is the consideration of reduction of cardiorespiratory fluctuations inherited in the original R-R intervals and the other is based upon the concept of nonlinear dynamics to construct the low-dimensional trajectory in the angle plot. The cross-correlation measure between the theoretical angle map and the numerically derived angle trajectory is used to separate recovery (0.73+/-0.13) from deterioration (0.25+/-0.08) of ICU patients. In addition, a simple physiologic (deterministic) model of the interaction between the cardiovascular system and baroreceptor control of arterial pressure is used to explain why homeostasis can exist in heart rate fluctuations. Our study provides a potential link between the clinical data and circulatory system. PMID:19162560

  1. Harmonic analysis of irradiation asymmetry for cylindrical implosions driven by high-frequency rotating ion beams.

    PubMed

    Bret, A; Piriz, A R; Tahir, N

    2012-03-01

    Cylindrical implosions driven by intense heavy ion beams should be instrumental in the near future for study of high-energy-density matter. By rotating the beam by means of a high-frequency wobbler, it should be possible to deposit energy in the outer layers of a cylinder, compressing the material deposited in its core. The beam's temporal profile should, however, generate an inevitable irradiation asymmetry likely to feed the Rayleigh-Taylor instability (RTI) during the implosion phase. In this paper, we compute the Fourier components of the target irradiation in order to make the connection with previous works on the RTI performed in this setting. Implementing one- and two-dimensional beam models, we find that these components can be expressed exactly in terms of the Fourier transform of the temporal beam profile. If T is the beam duration and ? its rotation frequency, "magic products" ?T can be identified which cancel the first harmonic of the deposited density, resulting in an improved irradiation symmetry. PMID:22587191

  2. Magnetic Dirac-harmonic maps

    NASA Astrophysics Data System (ADS)

    Branding, Volker

    2015-03-01

    We study a functional, whose critical points couple Dirac-harmonic maps from surfaces with a two form. The critical points can be interpreted as coupling the prescribed mean curvature equation to spinor fields. On the other hand, this functional also arises as part of the supersymmetric sigma model in theoretical physics. In two dimensions it is conformally invariant. We call critical points of this functional magnetic Dirac-harmonic maps. We study geometric and analytic properties of magnetic Dirac-harmonic maps including their regularity and the removal of isolated singularities.

  3. Spatial Harmonic Decomposition as a tool for unsteady flow phenomena analysis

    NASA Astrophysics Data System (ADS)

    Duparchy, A.; Guillozet, J.; De Colombel, T.; Bornard, L.

    2014-03-01

    Hydropower is already the largest single renewable electricity source today but its further development will face new deployment constraints such as large-scale projects in emerging economies and the growth of intermittent renewable energy technologies. The potential role of hydropower as a grid stabilizer leads to operating hydro power plants in "off-design" zones. As a result, new methods of analyzing associated unsteady phenomena are needed to improve the design of hydraulic turbines. The key idea of the development is to compute a spatial description of a phenomenon by using a combination from several sensor signals. The spatial harmonic decomposition (SHD) extends the concept of so-called synchronous and asynchronous pulsations by projecting sensor signals on a linearly independent set of a modal scheme. This mathematical approach is very generic as it can be applied on any linear distribution of a scalar quantity defined on a closed curve. After a mathematical description of SHD, this paper will discuss the impact of instrumentation and provide tools to understand SHD signals. Then, as an example of a practical application, SHD is applied on a model test measurement in order to capture and describe dynamic pressure fields. Particularly, the spatial description of the phenomena provides new tools to separate the part of pressure fluctuations that contribute to output power instability or mechanical stresses. The study of the machine stability in partial load operating range in turbine mode or the comparison between the gap pressure field and radial thrust behavior during turbine brake operation are both relevant illustrations of SHD contribution.

  4. Harmonic analysis and FPGA implementation of SHE controlled three phase CHB 11-level inverter in MV drives using deterministic and stochastic optimization techniques.

    PubMed

    Vesapogu, Joshi Manohar; Peddakotla, Sujatha; Kuppa, Seetha Rama Anjaneyulu

    2013-01-01

    With the advancements in semiconductor technology, high power medium voltage (MV) Drives are extensively used in numerous industrial applications. Challenging technical requirements of MV Drives is to control multilevel inverter (MLI) with less Total harmonic distortion (%THD) which satisfies IEEE standard 519-1992 harmonic guidelines and less switching losses. Among all modulation control strategies for MLI, Selective harmonic elimination (SHE) technique is one of the traditionally preferred modulation control technique at fundamental switching frequency with better harmonic profile. On the other hand, the equations which are formed by SHE technique are highly non-linear in nature, may exist multiple, single or even no solution at particular modulation index (MI). However, in some MV Drive applications, it is required to operate over a range of MI. Providing analytical solutions for SHE equations during the whole range of MI from 0 to 1, has been a challenging task for researchers. In this paper, an attempt is made to solve SHE equations by using deterministic and stochastic optimization methods and comparative harmonic analysis has been carried out. An effective algorithm which minimizes %THD with less computational effort among all optimization algorithms has been presented. To validate the effectiveness of proposed MPSO technique, an experiment is carried out on a low power proto type of three phase CHB 11- level Inverter using FPGA based Xilinx's Spartan -3A DSP Controller. The experimental results proved that MPSO technique has successfully solved SHE equations over all range of MI from 0 to 1, the %THD obtained over major range of MI also satisfies IEEE 519-1992 harmonic guidelines too. PMID:24010030

  5. Transient analysis of nonlinear transmission lines by hybrid harmonic balance method

    Microsoft Academic Search

    Akio Ushidat; Leon O. Chua

    1993-01-01

    Abstracb We discuss a transient analysis of transmission lines terminated by non- linear subnetworks. In this analysis, the circuit is partitioned into the transmission line and nonlinear subnetwork by using substitution source. The transmission line is solved by the phasor technique or perturbation method, and the nonlinear sub- network by a numerical integration technique. We calculate the the substitution source

  6. Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE

    Microsoft Academic Search

    Rich Pawlowicz; Bob Beardsley; Steve Lentz

    2002-01-01

    A standard part of any oceanic pressure gauge or current meter analysis is the separation of tidal from non-tidal components of the signal. The tidal signal can either be discarded, or its characteristics described in some fashion useful for further analysis. Although tidal signals can be removed by standard high or bandpass filtering techniques, their relatively deterministic character and large

  7. A probabilistic approach to the dynamic analysis of ducts subjected to multibase harmonic and random excitation. [for Space Shuttle Main Engine

    NASA Technical Reports Server (NTRS)

    Debchaudhury, Amit; Rajagopal, K. R.; Ho, H.; Newell, J. F.

    1990-01-01

    The dynamic behavior of the discharge duct of the high-pressure oxidizer turbopump of a cryogenic rocket motor is investigated analytically. The probabilistic analysis program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress; Cruse et al., 1988) is used to treat the uncertainties due to random and harmonic excitation (e.g., pump noise, pump-induced harmonics, and combustion noise), variations in engine inlet pressure, and changes in system damping. The load modeling procedure, the variation in power-spectral density in different zones of the engine structure, and the dynamic structural-analysis technique are described, and the numerical results of the NESSUS analysis are presented in extensive tables and graphs and discussed in detail.

  8. An Analysis of Physics Graduate Admission Data

    E-print Network

    Makkinje, Jan A

    2015-01-01

    We use self-reported data from 2011--2014 and determine the academic profile of accepted students at physics graduate programs in the United States. We analyze the accepted students' grade point averages and physics Graduate Record Examination (GRE) scores. We also compare the physics GRE scores of accepted students to their grade point averages.

  9. PHYSICAL REVIEW E 88, 062142 (2013) Reaction-diffusion theory in the presence of an attractive harmonic potential

    E-print Network

    Kenkre, V.M.

    2013-01-01

    PHYSICAL REVIEW E 88, 062142 (2013) Reaction-diffusion theory in the presence of an attractive and photosynthesis. Funneling phenomena attract excitations in photosynthetic antennae and molecular crystals ligand binding [12,13]. To bind at an enzyme's active site, a ligand must diffuse or be transported

  10. Cost and performance analysis of physical security systems

    SciTech Connect

    Hicks, M.J. [Sandia National Labs., Albuquerque, NM (United States); Yates, D.; Jago, W.H.; Phillips, A.W. [Tecolote Research, Inc., Santa Barbara, CA (United States)

    1998-04-01

    Analysis of cost and performance of physical security systems can be a complex, multi-dimensional problem. There are a number of point tools that address various aspects of cost and performance analysis. Increased interest in cost tradeoffs of physical security alternatives has motivated development of an architecture called Cost and Performance Analysis (CPA), which takes a top-down approach to aligning cost and performance metrics. CPA incorporates results generated by existing physical security system performance analysis tools, and utilizes an existing cost analysis tool. The objective of this architecture is to offer comprehensive visualization of complex data to security analysts and decision-makers.

  11. A Comparative Study of the Harmonic and Arithmetic Averaging of Diffusion Coefficients for Non-linear Heat Conduction Problems

    SciTech Connect

    Samet Y. Kadioglu; Robert R. Nourgaliev; Vincent A. Mousseau

    2008-03-01

    We perform a comparative study for the harmonic versus arithmetic averaging of the heat conduction coefficient when solving non-linear heat transfer problems. In literature, the harmonic average is the method of choice, because it is widely believed that the harmonic average is more accurate model. However, our analysis reveals that this is not necessarily true. For instance, we show a case in which the harmonic average is less accurate when a coarser mesh is used. More importantly, we demonstrated that if the boundary layers are finely resolved, then the harmonic and arithmetic averaging techniques are identical in the truncation error sense. Our analysis further reveals that the accuracy of these two techniques depends on how the physical problem is modeled.

  12. Random harmonic analysis program, L221 (TEV156). Volume 1: Engineering and usage

    NASA Technical Reports Server (NTRS)

    Miller, R. D.; Graham, M. L.

    1979-01-01

    A digital computer program capable of calculating steady state solutions for linear second order differential equations due to sinusoidal forcing functions is described. The field of application of the program, the analysis of airplane response and loads due to continuous random air turbulence, is discussed. Optional capabilities including frequency dependent input matrices, feedback damping, gradual gust penetration, multiple excitation forcing functions, and a static elastic solution are described. Program usage and a description of the analysis used are presented.

  13. Theoretical Analysis for Obtaining Physical Properties of Composite Electrodes

    E-print Network

    Weidner, John W.

    Theoretical Analysis for Obtaining Physical Properties of Composite Electrodes Parthasarathy M Carolina 29208, USA b Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA A theoretical analysis is presented that allows in situ measurements of the physical properties of a composite electrode

  14. Quantitative Fault Propagation Analysis for Networked Cyber-Physical Systems

    E-print Network

    Briesemeister, Linda

    Quantitative Fault Propagation Analysis for Networked Cyber-Physical Systems Linda Briesemeister an approach to ana- lyzing a model of networked cyber-physical systems for fault propagation. We present as numeric evaluation to perform a quantitative fault analysis. Our models are built from a few building

  15. Application of multilayer mirror for harmonic analysis in soft X-ray region

    NASA Astrophysics Data System (ADS)

    Modi, Mohammed H.; Gupta, R. K.; Lodha, G. S.

    2012-06-01

    Order contamination in soft x-ray beamline is a severe problem which poses difficulty in various analysis techniques. Generally grating analyzer is used to estimate the higher order contribution where poor knowledge of wall and land roughness contribution makes it difficult to get theoretical fit and so analysis gives qualitative estimation only. Here we demonstrate the application of multilayer mirror for accurate determination of order contamination in Toroidal grating monochromator (TGM) at reflectivity beamline of Indus-1. We used a Mo/Si multilayer of d˜100Å period to quantify 2nd and 3rd order composition to identify order contamination below 0.5% or better.

  16. The 2dF Galaxy Redshift Survey: Spherical Harmonics analysis of fluctuations in the final catalogue

    E-print Network

    Will J. Percival; Daniel Burkey; Alan Heavens; Andy Taylor; Shaun Cole; John A. Peacock; Carlton M. Baugh; Joss Bland-Hawthorn; Terry Bridges; Russell Cannon; Matthew Colless; Chris Collins; Warrick Couch; Gavin Dalton; Roberto De Propris; Simon P. Driver; George Efstathiou; Richard S. Ellis; Carlos S. Frenk; Karl Glazebrook; Carole Jackson; Ofer Lahav; Ian Lewis; Stuart Lumsden; Steve Maddox; Peder Norberg; Bruce A. Peterson; Will Sutherland; Keith Taylor

    2004-06-23

    We present the result of a decomposition of the 2dFGRS galaxy overdensity field into an orthonormal basis of spherical harmonics and spherical Bessel functions. Galaxies are expected to directly follow the bulk motion of the density field on large scales, so the absolute amplitude of the observed large-scale redshift-space distortions caused by this motion is expected to be independent of galaxy properties. By splitting the overdensity field into radial and angular components, we linearly model the observed distortion and obtain the cosmological constraint Omega_m^{0.6} sigma_8=0.46+/-0.06. The amplitude of the linear redshift-space distortions relative to the galaxy overdensity field is dependent on galaxy properties and, for L_* galaxies at redshift z=0, we measure beta(L_*,0)=0.58+/-0.08, and the amplitude of the overdensity fluctuations b(L_*,0) sigma_8=0.79+/-0.03, marginalising over the power spectrum shape parameters. Assuming a fixed power spectrum shape consistent with the full Fourier analysis produces very similar parameter constraints.

  17. Remarks on History of Abstract Harmonic Analysis Radomir S. Stankovic, Jaakko T. Astola1

    E-print Network

    Karpovsky, Mark

    , Euler applied the method he disclosed to a function derived from analysis of movement of planets, Clairaut derived a cosinus series representa- tion of a function derived in a study of the movement of the Sun. Figure 5: Clairaut. In 1777, in solving some astronomical problems, Euler determined coefficients

  18. Multiple harmonic ULF waves in the plasma sheet boundary layer: Instability analysis

    E-print Network

    California at Berkeley, University of

    electromagnetic waves with fundamental frequency near the local proton cyclotron frequency, Wcp, were recently December 2010. [1] Multipleharmonic electromagnetic waves in the ULF band have occasionally been observed functions. Analysis of wave instability using the WHAMP electromagnetic plasma wave dispersion code

  19. Analysis of harmonics for an elongated FTMS cell with multiple electrode detection

    Microsoft Academic Search

    E. N. Nikolaev; V. S. Rakov; J. H. Futrell

    1996-01-01

    The form of FTMS signals is analyzed for the general case of multiple electrode ICR cells with detailed results for two, eight and sixteen electrodes. The analysis is based on an elongated cylindrical cell to reduce the problem of treating the electric field distribution to two dimensions. The relative contributions of cyclotron and magnetron motion to the detected signal are

  20. Constructing analysis-suitable parameterization of computational domain from CAD boundary by variational harmonic method

    E-print Network

    Paris-Sud XI, Université de

    Constructing analysis-suitable parameterization of computational domain from CAD boundary-suitable parameterization of computational domain from CAD boundary for 2D and 3D isogeometric applications. Different from computational approach that offers the possibility of seamless integration between CAD and CAE. The method uses

  1. Constructing analysis-suitable parameterization of computational domain from CAD boundary by variational harmonic method

    E-print Network

    Paris-Sud XI, Université de

    Constructing analysis-suitable parameterization of computational domain from CAD boundary-suitable parameterization of computational domain from CAD boundary for 2D and 3D isogeometric applications. Different from that offers the possibility of seamless integration between CAD and CAE. The method uses the same type

  2. Killing vector fields and harmonic superfield theories

    SciTech Connect

    Groeger, Josua, E-mail: groegerj@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, 12489 Berlin (Germany)

    2014-09-15

    The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.

  3. Analysis of star pair latitudes. [earth tides tesseral harmonics, and polar wandering

    NASA Technical Reports Server (NTRS)

    Graber, M. A.

    1978-01-01

    Star pair latitude observations forming the basis for the pole positions reported by the International Polar Motion Service (IPMS) are processed to produce a mean pole position. However, the time series of raw observations contains high frequency information which is lost in the calculation of the mean pole. Analysis of 2931 star pair observations reveals a possible large excitation at one cycle per solar day. The average power level in the frequency band of the tesseral tides is seen to be high, although the peaks do not occur at the expected tidal frequencies.

  4. Harmonic engine

    DOEpatents

    Bennett, Charles L.; Sewall, Noel; Boroa, Carl

    2014-08-19

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into of the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. Upon releasing the inlet valve the inlet valve head undergoes a single oscillation past the equilibrium positio to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. Protrusions carried either by the inlet valve head or piston head are used to bump open the inlet valve from the closed position and initiate the single oscillation of the inlet valve head, and protrusions carried either by the outlet valve head or piston head are used to close the outlet valve ahead of the bump opening of the inlet valve.

  5. Chemistry 160: Physical Measurements and Analysis

    NSDL National Science Digital Library

    Steinmetz, Wayne E.

    This site contains lab experiments for both analytical and physical chemical measurements. There are 6 analytical experiments: data acquisition, AAS, voltammetry, ASV, GC-MS, stop-flow kinetics and HPLC. Experiments use real samples and are ready for implementation.

  6. Spherical Harmonics Analysis of the ECMWF Global Wind Fields at the 10-Meter Height Level During 1985: A Collection of Figures Illustrating Results

    NASA Technical Reports Server (NTRS)

    Sanchez, Braulio V.; Nishihama, Masahiro

    1997-01-01

    Half-daily global wind speeds in the east-west (u) and north-south (v) directions at the 10-meter height level were obtained from the European Centre for Medium Range Weather Forecasts (ECMWF) data set of global analyses. The data set covered the period 1985 January to 1995 January. A spherical harmonic expansion to degree and order 50 was used to perform harmonic analysis of the east-west (u) and north-south (v) velocity field components. The resulting wind field is displayed, as well as the residual of the fit, at a particular time. The contribution of particular coefficients is shown. The time variability of the coefficients up to degree and order 3 is presented. Corresponding power spectrum plots are given. Time series analyses were applied also to the power associated with degrees 0-10; the results are included.

  7. Quantitative analysis of vascular heterogeneity in breast lesions using contrast-enhanced 3-D harmonic and subharmonic ultrasound imaging.

    PubMed

    Sridharan, Anush; Eisenbrey, John R; Machado, Priscilla; Ojeda-Fournier, Haydee; Wilkes, Annina; Sevrukov, Alexander; Mattrey, Robert F; Wallace, Kirk; Chalek, Carl L; Thomenius, Kai E; Forsberg, Flemming

    2015-03-01

    Ability to visualize breast lesion vascularity and quantify the vascular heterogeneity using contrast-enhanced 3-D harmonic (HI) and subharmonic (SHI) ultrasound imaging was investigated in a clinical population. Patients (n = 134) identified with breast lesions on mammography were scanned using power Doppler imaging, contrast-enhanced 3-D HI, and 3-D SHI on a modified Logiq 9 scanner (GE Healthcare). A region of interest corresponding to ultrasound contrast agent flow was identified in 4D View (GE Medical Systems) and mapped to raw slice data to generate a map of time-intensity curves for the lesion volume. Time points corresponding to baseline, peak intensity, and washout of ultrasound contrast agent were identified and used to generate and compare vascular heterogeneity plots for malignant and benign lesions. Vascularity was observed with power Doppler imaging in 84 lesions (63 benign and 21 malignant). The 3-D HI showed flow in 8 lesions (5 benign and 3 malignant), whereas 3-D SHI visualized flow in 68 lesions (49 benign and 19 malignant). Analysis of vascular heterogeneity in the 3-D SHI volumes found benign lesions having a significant difference in vascularity between central and peripheral sections (1.71 ± 0.96 vs. 1.13 ± 0.79 dB, p < 0.001, respectively), whereas malignant lesions showed no difference (1.66 ± 1.39 vs. 1.24 ± 1.14 dB, p = 0.24), indicative of more vascular coverage. These preliminary results suggest quantitative evaluation of vascular heterogeneity in breast lesions using contrast-enhanced 3-D SHI is feasible and able to detect variations in vascularity between central and peripheral sections for benign and malignant lesions. PMID:25935933

  8. Can recent innovations in harmonic analysis 'explain' key findings in natural image statistics?

    PubMed

    Donoho, D L; Flesia, A G

    2001-08-01

    Recently, applied mathematicians have been pursuing the goal of sparse coding of certain mathematical models of images with edges. They have found by mathematical analysis that, instead of wavelets and Fourier methods, sparse coding leads towards new systems: ridgelets and curvelets. These new systems have elements distributed across a range of scales and locations, but also orientations. In fact they have highly direction-specific elements and exhibit increasing numbers of distinct directions as we go to successively finer scales. Meanwhile, researchers in natural scene statistics (NSS) have been attempting to find sparse codes for natural images. The new systems they have found by computational optimization have elements distributed across a range of scales and locations, but also orientations. The new systems are certainly unlike wavelet and Gabor systems, on the one hand because of the multi-orientation and on the other hand because of the multi-scale nature. There is a certain degree of visual resemblance between the findings in the two fields, which suggests the hypothesis that certain important findings in the NSS literature might possibly be explained by the slogan: edges are the dominant features in images, and curvelets are the right tool for representing edges. We consider here certain empirical consequences of this hypothesis, looking at key findings of the NSS literature and conducting studies of curvelet and ridgelet transforms on synthetic and real images, to see if the results are consistent with predictions from this slogan. Our first experiment measures the nonGaussianity of Fourier, wavelet, ridgelet and curvelet coefficients over a database of synthetic and photographic images. Empirically the curvelet coefficients exhibit noticeably higher kurtosis than wavelet, ridgelet, or Fourier coefficients. This is consistent with the hypothesis. Our second experiment studies the inter-scale correlation of wavelet coefficient energies at the same location. We describe a simple experiment showing that presence of edges explains these correlations. We also develop a crude nonlinear 'partial correlation' by considering the correlation between wavelet parents and children after a few curvelet coefficients are removed. When we kill the few biggest coefficients of the curvelet transform, much of the correlation between wavelet subbands disappears--consistent with the hypothesis. We suggest implications for future discussions about NSS. PMID:11563535

  9. [1] Fuhr, H. Abstract harmonic analysis of continuous wavelet transforms, Lecture Notes in Math. 1863, Springer Verlag, 2005. [2] Geller, D. Mayeli, A. Continuous Wavelets and Frames on Stratified Lie Groups I, Journal of Fourier Analysis and Applications

    E-print Network

    Mayeli, Azita

    References [1] F¨uhr, H. Abstract harmonic analysis of continuous wavelet transforms, Lecture Notes. Continuous and discrete wavelet transformations on the Heisenberg group, PhD thesis, Technische Universit in Math. 1863, Springer Verlag, 2005. [2] Geller, D. Mayeli, A. Continuous Wavelets and Frames

  10. Physics and Physical Oceanography Data Report 2004-1 Analysis of Physical Oceanographic Data from

    E-print Network

    deYoung, Brad

    Department of Physics and Physical Oceanography Memorial University of Newfoundland St. John's, Newfoundland on the west coast of Newfoundland. The moorings were deployed over the time period to measure the velocity

  11. Physics and Physical Oceanography Data Report 2002-1 Analysis of Physical Oceanographic Data from

    E-print Network

    deYoung, Brad

    Department of Physics and Physical Oeanography Memorial University of Newfoundland St. John's, Newfoundland A, Newfoundland. A cruise was carried out in this region during May 2001 with the intention of quantifying local

  12. Physics and Physical Oceanography Data Report 2002-2 Analysis of Physical Oceanographic Data from

    E-print Network

    deYoung, Brad

    of Physics and Physical Oeanography Memorial University of Newfoundland St. John's, Newfoundland A1B 3X7 #12 of the Avalon peninsula, Newfoundland, to deploy oceanographic meters with which to collect data

  13. Physics and Analysis at a Hadron Collider - Searching for New Physics (2/3)

    ScienceCinema

    None

    2011-10-06

    This is the second lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This second lecture discusses techniques important for analyses searching for new physics using the CDF B_s --> mu+ mu- search as a specific example. The lectures are aimed at graduate students.

  14. Physical Education for Health and Wellbeing: A Discourse Analysis of Scottish Physical Education Curricular Documentation

    ERIC Educational Resources Information Center

    McEvilly, Nollaig; Verheul, Martine; Atencio, Matthew; Jess, Mike

    2014-01-01

    This paper provides an analysis of the discourses associated with physical education in Scotland's "Curriculum for Excellence". We implement a poststructural perspective in order to identify the discourses that underpin the physical education sections of the "Curriculum for Excellence" "health and well-being"…

  15. Standing Waves: Harmonics and Patterns

    NSDL National Science Digital Library

    Henderson, Tom

    This high school physics tutorial provides an introduction to standing waves. The site contains a description of such waves and related features such as nodes, antinodes, and interference. The site presents several simulations that demonstrate harmonics and their associated wave patterns.

  16. A comparative analysis of physical-layer rateless coding architectures

    E-print Network

    Romero, David Luis

    2014-01-01

    An analysis of rateless codes implemented at the physical layer is developed. Our model takes into account two aspects of practical communication system design that are abstracted away in many existing works on the subject. ...

  17. 24 CFR 401.451 - PAE Physical Condition Analysis (PCA).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MULTIFAMILY HOUSING MORTGAGE AND HOUSING ASSISTANCE RESTRUCTURING PROGRAM (MARK-TO-MARKET) Restructuring Plan § 401.451 PAE Physical Condition Analysis (PCA). (a) Review and...

  18. Physical and numerical analysis of three dimensional extrusion process

    Microsoft Academic Search

    Hasan Sofuoglu; Hasan Gedikli

    2004-01-01

    Three dimensional extrusion process was simulated by utilizing physical modeling technique and numerical method based on the finite element analysis. Plasticine, a soft modeling material, which shows elastic–plastic flow behavior, and conical die were used in the extrusion process for both physical and numerical simulations. The extrusion billet was made from alternating slabs of black and stone color of Plasticine

  19. Interactive ergonomic analysis of a physically disabled person's workplace

    E-print Network

    Paris-Sud XI, Université de

    Interactive ergonomic analysis of a physically disabled person's workplace Matthieu Aubry1 , Fr approach for in- teractive ergonomics evaluation, and especially adaptation of physically disabled people's workplaces. After a general survey of existing tools, we describe the requirements to perform ergonomic

  20. Simulation and Analysis of Physical Processes for Aiding Technology Development

    E-print Network

    Cole, Dan C.

    4/16/03 1 Simulation and Analysis of Physical Processes for Aiding Technology Development Dan Cole Dept. Manufacturing Engineering, Boston University #12;4/16/03 2 Simulation of Physical Processes of technology helps to dictate the appropriate level of simulation/modeling. Both directions are useful! One

  1. Dimensional Analysis in Physics and the Buckingham Theorem

    ERIC Educational Resources Information Center

    Misic, Tatjana; Najdanovic-Lukic, Marina; Nesic, Ljubisa

    2010-01-01

    Dimensional analysis is a simple, clear and intuitive method for determining the functional dependence of physical quantities that are of importance to a certain process. However, in physics textbooks, very little space is usually given to this approach and it is often presented only as a diagnostic tool used to determine the validity of…

  2. An Analysis of Laboratory Activities: Project Physics and PSSC.

    ERIC Educational Resources Information Center

    Lunetta, Vincent N.; Tamir, Pinchas

    1981-01-01

    This report reviews some goals for laboratory activities in contemporary science teaching, discusses an investigation that analyzed and compared laboratory activities from two major physics guides, and discusses the implications of the goals and analysis for physics teaching. Six major deficiencies in the two laboratory handbooks are identified.…

  3. Exhaled breath analysis: physical methods, instruments, and medical diagnostics

    NASA Astrophysics Data System (ADS)

    Vaks, V. L.; Domracheva, E. G.; Sobakinskaya, E. A.; Chernyaeva, M. B.

    2014-07-01

    This paper reviews the analysis of exhaled breath, a rapidly growing field in noninvasive medical diagnostics that lies at the intersection of physics, chemistry, and medicine. Current data are presented on gas markers in human breath and their relation to human diseases. Various physical methods for breath analysis are described. It is shown how measurement precision and data volume requirements have stimulated technological developments and identified the problems that have to be solved to put this method into clinical practice.

  4. Harmonic Oscillators as Bridges between Theories

    SciTech Connect

    Kim, Y.S. [Department of Physics, University of Maryland College Park, Maryland 20742 (United States); Noz, Marilyn E. [Department of Radiology, New York University, New York, New York 10016 (United States)

    2005-03-31

    Other than scattering problems where perturbation theory is applicable, there are basically two ways to solve problems in physics. One is to reduce the problem to harmonic oscillators, and the other is to formulate the problem in terms of two-by-two matrices. If two oscillators are coupled, the problem combines both two-by-two matrices and harmonic oscillators. This method then becomes a powerful research tool to cover many different branches of physics. Indeed, the concept and methodology in one branch of physics can be translated into another through the common mathematical formalism. It is noted that the present form of quantum mechanics is largely a physics of harmonic oscillators. Special relativity is the physics of the Lorentz group which can be represented by the group of by two-by-two matrices commonly called SL(2, c). Thus the coupled harmonic oscillators can therefore play the role of combining quantum mechanics with special relativity. Both Paul A. M. Dirac and Richard P. Feynman were fond of harmonic oscillators, while they used different approaches to physical problems. Both were also keenly interested in making quantum mechanics compatible with special relativity. It is shown that the coupled harmonic oscillators can bridge these two different approaches to physics.

  5. Spherical harmonic analysis of the PSCz galaxy catalogue: redshift distortions and the real-space power spectrum

    Microsoft Academic Search

    H. Tadros; W. E. Ballinger; A. N. Taylor; A. F. Heavens; G. Efstathiou; W. Saunders; C. S. Frenk; O. Keeble; R. McMahon; S. J. Maddox; S. Oliver; M. Rowan-Robinson; W. J. Sutherland; S. D. M. White

    1999-01-01

    We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. The PSCz redshift survey has almost all-sky coverage and includes IRAS galaxies to a flux limit of 0.6 Jy. Using maximum likelihood methods to examine (to first order) the distortion of the galaxy pattern resulting from redshift coordinates, we have measured

  6. IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 23, NO. 2, MARCH 2008 985 Analysis and Reduction of Time Harmonic Rotor

    E-print Network

    Hofmann, Heath F.

    with solid rotor construction have advantages in certain high-speed applications such as flywheel energy filter. Experimental results validate the proposed approach. Index Terms--filters, flywheels, harmonic-speed applications, such as flywheel energy storage systems. The rotor of a synchronous reluctance ma- chine design

  7. IEEE ISIE 2006, July 9-12, 2006, Montreal, Quebec, Canada Harmonic Analysis of Single-Phase Full Bridge

    E-print Network

    Lehn, Peter W.

    distribution system. It is therefore essential to predict the harmonic levels these converters produce as a variable resistor, one can convert Fig. 1 to Fig. 2, where Rd= Ron when the diode turns on, and Rd- Rff= blkdiag{K? 00}[2? 0 0'[n j} Note that: 1. A is a time varying matrix because Rd changes its values

  8. New marine harmonic standards

    Microsoft Academic Search

    Tony Hoevenaars; Ian Evans; Andy Lawson

    2010-01-01

    To address concerns associated with electrical power system harmonic distortion on ships and offshore oil rigs and platforms, marine regulating bodies have introduced strict new harmonic standards. These standards define the acceptable level of harmonic voltage distortion allowed on the vessels they certify. High-harmonic distortion levels are appearing as a result of the increased use of power-electronic drive converters for

  9. Spherical cap harmonic analysis

    Microsoft Academic Search

    G. V. Haines

    1985-01-01

    The solution of Laplace's equation, in spherical coordinates, is developd for the boundary value problem appropriate to fitting the geomagnetic field over a spherical cap. The solution involves associated Legendre functions of integral order but nonintegral degree. The basis functions comprise two infinite sets, within each of which the functions are mutually orthogonal. The series for the expansion of the

  10. Neural Representation of Concurrent Harmonic Sounds in Monkey Primary Auditory Cortex: Implications for Models of Auditory Scene Analysis

    PubMed Central

    Steinschneider, Mitchell; Micheyl, Christophe

    2014-01-01

    The ability to attend to a particular sound in a noisy environment is an essential aspect of hearing. To accomplish this feat, the auditory system must segregate sounds that overlap in frequency and time. Many natural sounds, such as human voices, consist of harmonics of a common fundamental frequency (F0). Such harmonic complex tones (HCTs) evoke a pitch corresponding to their F0. A difference in pitch between simultaneous HCTs provides a powerful cue for their segregation. The neural mechanisms underlying concurrent sound segregation based on pitch differences are poorly understood. Here, we examined neural responses in monkey primary auditory cortex (A1) to two concurrent HCTs that differed in F0 such that they are heard as two separate “auditory objects” with distinct pitches. We found that A1 can resolve, via a rate-place code, the lower harmonics of both HCTs, a prerequisite for deriving their pitches and for their perceptual segregation. Onset asynchrony between the HCTs enhanced the neural representation of their harmonics, paralleling their improved perceptual segregation in humans. Pitches of the concurrent HCTs could also be temporally represented by neuronal phase-locking at their respective F0s. Furthermore, a model of A1 responses using harmonic templates could qualitatively reproduce psychophysical data on concurrent sound segregation in humans. Finally, we identified a possible intracortical homolog of the “object-related negativity” recorded noninvasively in humans, which correlates with the perceptual segregation of concurrent sounds. Findings indicate that A1 contains sufficient spectral and temporal information for segregating concurrent sounds based on differences in pitch. PMID:25209282

  11. Harmonics and Resonance Issues with Wind Plants

    SciTech Connect

    Bradt, M. [IEEE PES Wind Plant Collector System Design Working Group; Badrzadeh, Babak [IEEE PES Wind Plant Collector System Design Working Group; Camm, E H [IEEE PES Wind Plant Collector System Design Working Group; Castillo, Nestor [IEEE PES Wind Plant Collector System Design Working Group; Mueller, David [IEEE PES Wind Plant Collector System Design Working Group; Siebert, T. [IEEE PES Wind Plant Collector System Design Working Group; Schoene, Jens [IEEE PES Wind Plant Collector System Design Working Group; Smith, Travis M [ORNL; Starke, Michael R [ORNL; Walling, R. [IEEE PES Wind Plant Collector System Design Working Group

    2011-01-01

    Wind plants are susceptible to lightly-damped resonances which can attract and amplify ambient grid harmonic distortion and magnify wind turbine harmonic generation. Long-accepted harmonic modeling assumptions and practices are not appropriate for wind plants. VSCs are not ideal current sources and grid impedance is important. Attention to modeling detail and thorough evaluation over range of conditions is critical to meaningful analysis. In general, wind turbines are very slight sources of harmonics. Most harmonic issues are a result of resonance, caused by capacitor banks (for reactive power compensation) or from the extensive underground cabling in a collector system. Converter controls instability can be exacerbated by power system resonances. In some cases this has caused severe voltage distorDon and other problems. The IEEE 519 recommended guidelines are very restrictive. I recommend that they are used to resolve serious harmonic issues, and not to create petty problems.

  12. Accelerator physics analysis with interactive tools

    SciTech Connect

    Holt, J.A.; Michelotti, L.

    1993-05-01

    Work is in progress on interactive tools for linear and nonlinear accelerator design, analysis, and simulation using X-based graphics. The BEAMLINE and MXYZPTLK class libraries, were used with an X Windows graphics library to build a program for interactively editing lattices and studying their properties.

  13. On the Correct Analysis of the Foundations of Theoretical Physics

    NASA Astrophysics Data System (ADS)

    Kalanov, Temur Z.

    2007-04-01

    The problem of truth in science -- the most urgent problem of our time -- is discussed. The correct theoretical analysis of the foundations of theoretical physics is proposed. The principle of the unity of formal logic and rational dialectics is a methodological basis of the analysis. The main result is as follows: the generally accepted foundations of theoretical physics (i.e. Newtonian mechanics, Maxwell electrodynamics, thermodynamics, statistical physics and physical kinetics, the theory of relativity, quantum mechanics) contain the set of logical errors. These errors are explained by existence of the global cause: the errors are a collateral and inevitable result of the inductive way of cognition of the Nature, i.e. result of movement from formation of separate concepts to formation of the system of concepts. Consequently, theoretical physics enters the greatest crisis. It means that physics as a science of phenomenon leaves the progress stage for a science of essence (information). Acknowledgment: The books ``Surprises in Theoretical Physics'' (1979) and ``More Surprises in Theoretical Physics'' (1991) by Sir Rudolf Peierls stimulated my 25-year work.

  14. Multiscale nonlinear frequency response analysis of single-layered graphene sheet under impulse and harmonic excitation using the atomistic finite element method

    NASA Astrophysics Data System (ADS)

    Gajbhiye, Sachin O.; Singh, S. P.

    2015-04-01

    The atomistic finite element method (AFEM) is a multiscale technique where a sequential mode is used to transfer information between two length scales to model and simulate nanostructures at the continuum level. This method is used in this paper to investigate the nonlinear frequency response of a single-layered graphene sheet (SLGS) for impulse and harmonic excitation. The multi-body interatomic Tersoff–Brenner (TB) potential is used to represent the energy between two adjacent carbon atoms. Based on the TB potential, the equivalent geometric and elastic properties of carbon–carbon bonds are derived which are consistent with the material constitutive relations. These properties are used further to derive the nonlinear material model (stress–strain curve) of carbon–carbon bonds based on the force–deflection curve using the multi-body interatomic Tersoff–Brenner potential. A square SLGS is considered and its nonlinear vibration characteristics under an impulse and harmonic excitation for bridged, cantilever and clamped boundary conditions are investigated using the derived nonlinear material model (NMM). Before using the proposed nonlinear material model, the derived equivalent geometric and elastic properties of carbon–carbon bond are validated using molecular dynamics simulation results. The geometric (large deformation) and material nonlinearities are included in the nonlinear frequency response analysis. The investigated results of the nonlinear frequency response analysis are compared with those of the linear frequency response analysis, and the effect of the nonlinear behavior of carbon–carbon bonds on the frequency response of SLGS is studied.

  15. A Fundamental Suppression Type Harmonic Analyzer

    Microsoft Academic Search

    J. H. Piddington

    1936-01-01

    The principles and design of an harmonic analyzer of novel form are described. The analyzer operates by suppressing the fundamental and passing the harmonics through an amplifier with a calibrated gain control to a cathode-ray oscillograph or vacuum tube voltmeter. The apparatus is designed for analysis of audio-frequency oscillations but could be used with frequencies of a much higher order

  16. Manipulating objects with a power assist robot in harmonic motion: Analysis of human features and object motions for control modification

    Microsoft Academic Search

    S. M. Mizanoor Rahman; Ryojun Ikeura; Hideki Sawai

    2010-01-01

    We designed a one-degree-of-freedom (vertical up-down motion) power assist robot for manipulating objects. We used a hypothesis that pertains to human's weight perception. The robot was simulated and subjects manipulated objects with the robot in harmonic motion i.e. the objects were repeatedly lifted up and lowered down in each trial. We then critically analyzed subject's weight perception, load forces and

  17. Harmonic motion analysis and control for manipulating objects with a power assist robot based on human characteristics

    Microsoft Academic Search

    S. M. M. Rahman; R. Ikeura; M. Nobe; H. Sawai

    2010-01-01

    We developed a one-degree-of-freedom (vertical up-down motion) power assist robot for manipulating objects. The robot system was simulated and subjects manipulated objects with the robot in harmonic motion i.e. the objects were repeatedly lifted up and lowered down during the simulation. We then critically analyzed human's weight perception, load forces and object's motion features. We then introduced a novel control

  18. Study and harmonic analysis of SVPWM techniques for VSI-Fed double-star induction motor drive

    Microsoft Academic Search

    Khoudir Marouani; Farid Khoucha; Lotfi Baghli; Djafar Hadiouche; Abdelaziz Kheloui

    2007-01-01

    In this paper, a comparison between continuous and discontinuous space vector PWM control of six-phase VSI fed a double-star induction motor drive (DSIM) is presented. The induction machine has two sets of three-phase stator windings spatially shifted by 30 electrical degrees. Each set of three-phase stator windings is fed by a three-phase inverter. The harmonic characteristics of the VSI feeding

  19. Color harmonization for images

    NASA Astrophysics Data System (ADS)

    Tang, Zhen; Miao, Zhenjiang; Wan, Yanli; Wang, Zhifei

    2011-04-01

    Color harmonization is an artistic technique to adjust a set of colors in order to enhance their visual harmony so that they are aesthetically pleasing in terms of human visual perception. We present a new color harmonization method that treats the harmonization as a function optimization. For a given image, we derive a cost function based on the observation that pixels in a small window that have similar unharmonic hues should be harmonized with similar harmonic hues. By minimizing the cost function, we get a harmonized image in which the spatial coherence is preserved. A new matching function is proposed to select the best matching harmonic schemes, and a new component-based preharmonization strategy is proposed to preserve the hue distribution of the harmonized images. Our approach overcomes several shortcomings of the existing color harmonization methods. We test our algorithm with a variety of images to demonstrate the effectiveness of our approach.

  20. ATOMIC AND MOLECULAR PHYSICS: Retrieval of Electron Return Time from High-order Harmonics Generated in a Mixture of He and Ne Gases

    NASA Astrophysics Data System (ADS)

    Jin, Cheng; Zhou, Xiao-Xin; Zhao, Song-Feng

    2010-04-01

    In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell's equation of harmonic held. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 (2007) 061403(R)] in macroscopic response level. Finally, using least squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 (2007) 153904] when the gas jet is put after the laser focus.

  1. Pathway of bichromatic high-order harmonic generation

    SciTech Connect

    Cai, Jun; Qiao, Haoxue [Department of Physics, Wuhan University, Wuhan 430072 (China)

    2007-03-15

    We present a theoretical study of the pathway of harmonic generation in bichromatic linearly polarized laser fields. A 'harmonic-collapse' phenomenon is observed in the power spectrum for a particular value of the amplitude ratio of two components of the external field. We employ an offset frequency shift to the additional field to distinguish the harmonic pathway and then to explain the harmonic-collapse phenomenon. The harmonic intensity as a function of the relative amplitude ratio and, furthermore, the fine structure of the harmonic spectrum can be well understood on the basis of a pathway analysis.

  2. Present status of JADE's gammagamma-physics analysis

    Microsoft Academic Search

    W. Bartel; D. Cord; P. Dittmann; R. Eichler; R. Felst; D. Haidt; S. Kawabata; H. Krehbiel; B. Naroska; L. H. O'Neill; J. Olsson; P. Steffen; W. L. Yen; E. Elsen; M. Helm; K. Meier; A. Peterson; G. Weber; H. Drum; J. Heintze; G. Heinzelmann; R. D.. Heuer; J. von Krogh; P. Lennert; H. Matsumura; T. Nozaki; H. Rieseberg; A. Wagner; D. C. Darvill; F. Foster; G. Hughes; H. Wriedt; J. Allison; J. Armitage; A. Ball; I. Duerdoth; J. Hassard; F. Loebinger; H. McCann; B. King; A. MacBeth; H. Mills; P. G. Murphy; H. Prosper; K. Stephens; C. Clark; M. C. Goddard; R. Marshall; G. F. Pearce; M. Imori; T. Kobayashi; S. Komamiya; M. Koshiba; M. Minowa; S. Orito; A. Sato; T. Suda; H. Takeda; Y. Totsuka; Y. Watanabe; S. Yamada; C. Yanagisawa

    1980-01-01

    The present status of the -physics analysis performed by the JADE-Collaboration is reported. The reaction ee ee is observed at beam-energies of 6 GeV and 15 GeV, and it is compared with predictions from QED. The reaction ee ee + hadrons is observed at 15 GeV beam-energy. Several distributions of physical quantities are shown.

  3. Computational and Physical Analysis of Catalytic Compounds

    NASA Astrophysics Data System (ADS)

    Wu, Richard; Sohn, Jung Jae; Kyung, Richard

    2015-03-01

    Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

  4. A physical analysis of nucleosome positioning

    NASA Astrophysics Data System (ADS)

    Gerland, Ulrich

    2015-03-01

    The first level of genome packaging in eukaryotic cells involves the formation of dense nucleosome arrays, with DNA coverage near 90% in yeasts. A high nucleosome coverage is essential for cells, e.g. to prevent cryptic transcription, and the local positions of specific nucleosomes can play an important role in gene regulation. It is known that in vivo nucleosome positions are affected by a complex mix of passive and active mechanisms, including sequence-specific histone-DNA binding, nucleosome-nucleosome interactions, ATP-dependent remodeling enzymes, transcription, and DNA replication. Yet, the statistical distribution of nucleosome positions is extremely well described by simple physical models that treat the chromatin fiber as an interacting one-dimensional gas. I will discuss how can we interpret this surprising observation from a mechanistic perspective. I will also discuss the kinetics of the interacting gas model, which is pertinent to the question of how cells achieve the high nucleosome coverage within a short time, e.g. after DNA replication.

  5. Accelerator physics analysis with an integrated toolkit

    SciTech Connect

    Holt, J.A.; Michelotti, L.; Satogata, T.

    1992-08-01

    Work is in progress on an integrated software toolkit for linear and nonlinear accelerator design, analysis, and simulation. As a first application, ``beamline`` and ``MXYZPTLK`` (differential algebra) class libraries, were used with an X Windows graphics library to build an user-friendly, interactive phase space tracker which, additionally, finds periodic orbits. This program was used to analyse a theoretical lattice which contains octupoles and decapoles to find the 20th order, stable and unstable periodic orbits and to explore the local phase space structure.

  6. Accelerator physics analysis with an integrated toolkit

    SciTech Connect

    Holt, J.A.; Michelotti, L.; Satogata, T.

    1992-08-01

    Work is in progress on an integrated software toolkit for linear and nonlinear accelerator design, analysis, and simulation. As a first application, beamline'' and MXYZPTLK'' (differential algebra) class libraries, were used with an X Windows graphics library to build an user-friendly, interactive phase space tracker which, additionally, finds periodic orbits. This program was used to analyse a theoretical lattice which contains octupoles and decapoles to find the 20th order, stable and unstable periodic orbits and to explore the local phase space structure.

  7. Simple Harmonic Motion in Harmonic Plane Waves.

    ERIC Educational Resources Information Center

    Benumof, Reuben

    1980-01-01

    Discusses the distribution of kinetic and potential energy in transverse and longitudinal waves and examines the transmission of power and momentum. This discussion is intended to aid in understanding the simple harmonic motion of a particle involved in the propagation of a harmonic mechanical plane wave. (HM)

  8. On Harmonic Superspace

    E-print Network

    P. S. Howe

    1998-12-15

    A short survey of some aspects of harmonic superspace is given. In particular, the $d=3, N=8$ scalar supermultiplet and the $d=6, N=(2,0)$ tensor multiplet are described as analytic superfields in appropriately defined harmonic superspaces.

  9. Spectral Analysis of Vibrational Harmonic Motion by use of a Continuous-Wave CO2 Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Jarzembski, Maurice A.; Srivastava, Vandana

    1999-01-01

    Vibrational motion of a harmonic oscillator was investigated using a focused continuous wave CO2 Doppler lidar at 9.1 microns wavelength. A continuum of frequencies along with many discrete, equally spaced, resonant frequency modes was observed. The frequency modes are similar in structure to the oscillatory longitudinal modes of a laser cavity and arise because of interference of the natural resonant frequency of the oscillator with specific frequencies within the continuum. The spectra revealed departures from linear motion for vigorous vibrations of the oscillator. Each consecutive resonant frequency mode occurred for a movement of the oscillator much less than the wavelength of incident lidar radiation.

  10. Harmonization of Biodiesel Specifications

    SciTech Connect

    Alleman, T. L.

    2008-02-01

    Worldwide biodiesel production has grown dramatically over the last several years. Biodiesel standards vary across countries and regions, and there is a call for harmonization. For harmonization to become a reality, standards have to be adapted to cover all feedstocks. Additionally, all feedstocks cannot meet all specifications, so harmonization will require standards to either tighten or relax. For harmonization to succeed, the biodiesel market must be expanded with the alignment of test methods and specification limits, not contracted.

  11. Harmonic synchronizations of spacetime

    SciTech Connect

    Bona, C.; Masso, J.

    1988-10-15

    The spacetime slicings associated with a harmonic time coordinate (harmonic synchronizations) are considered and their usefulness in the field of numerical relativity is studied. Harmonic synchronizations are shown to avoid singularities in the same way that the widely used maximal slicings do. Both kinds of slicing are compared in stationary axisymmetric spacetimes, homogeneous cosmological models, and Kerr-Newman black holes.

  12. Tissue harmonic imaging

    Microsoft Academic Search

    Michalakis A. Averkiou

    2000-01-01

    Harmonic imaging was originally developed for microbubble contrast agents in the early 90s under the assumption that tissue is linear and all harmonic echoes are generated by the bubbles. In fact, tissue, like bubbles, is a nonlinear medium. Whereas the harmonic echoes from bubbles have their origins in nonlinear scattering, those from tissue are a result of nonlinear propagation. The

  13. Tissue harmonic ultrasonic imaging

    Microsoft Academic Search

    Michalakis A. Averkiou

    2001-01-01

    Harmonic imaging was originally developed for microbubble contrast agents in the early 90s under the assumption that tissue is linear and all harmonic echoes are generated by the bubbles. In fact, tissue, like bubbles, is a nonlinear medium. Whereas the harmonic echoes from bubbles have their origins in nonlinear scattering, those from tissue are a result of nonlinear propagation. The

  14. Data Preservation and Long Term Analysis in High Energy Physics

    E-print Network

    David M. South

    2009-07-09

    High energy physics data is a long term investment and contains the potential for physics results beyond the lifetime of a collaboration. Many existing experiments are concluding their physics programs, and looking at ways to preserve their data heritage. Preservation of high-energy physics data and data analysis structures is a challenge, and past experience has shown it can be difficult if adequate planning and resources are not provided. A study group has been formed to provide guidelines for such data preservation efforts in the future. Key areas to be investigated were identified at a workshop at DESY in January 2009, to be followed by a workshop at SLAC in May 2009. More information can be found at http://dphep.org

  15. Creativity in theoretical physics: A situational analysis of the fifth Solvay Council on Physics, 1927

    NASA Astrophysics Data System (ADS)

    First, Leili K.

    This dissertation investigates the intersections and interactions of factors which enhance and inhibit creativity in theoretical physics research, using a situational analysis of the fifth Solvay Council on Physics of 1927 (Solvay 1927), a pivotal point in the history of quantum physics. Situational analysis is a postmodern variant of the grounded theory method which views a situation as the unit of analysis and adds situational mapping as an analytic tool. This method specifically works against normalizing or simplifying the points of view, instead drawing out diversity, complexity, and contradiction. It results in "theorizing" rather than theory. This research differs from other analyses of the development of quantum mechanics in looking at technical issues as well as individual, collective, and societal factors. Data examined in this historical analysis includes theoretical papers, conference proceedings, personal letters, and commentary and analysis, both contemporaneous and modern. Literature related to scientific creativity was also consulted. Mapping the situation as a master discourse of Niels Bohr overlapping and interacting with co-existent major discourses on matrix mechanics/Copenhagen interpretation, wave mechanics, and the pilot-wave theory resulted in the most descriptive illustration of the factors influencing scientific creativity before and after Solvay 1927. The master discourse strongly influenced the major discourses and generated the "Copenhagen spirit" which effectively marginalized discourses other than matrix mechanics/Copenhagen interpretation after Solvay 1927.

  16. RMC - A Monte Carlo code for reactor physics analysis

    SciTech Connect

    Wang, K.; Li, Z.; She, D.; Liang, J.; Xu, Q.; Qiu, A.; Yu, J.; Sun, J.; Fan, X.; Yu, G. [Department of Engineering Physics, Tsinghua University, Liuqing Building, Beijing, 100084 (China)

    2013-07-01

    A new Monte Carlo neutron transport code RMC has been being developed by Department of Engineering Physics, Tsinghua University, Beijing as a tool for reactor physics analysis on high-performance computing platforms. To meet the requirements of reactor analysis, RMC now has such functions as criticality calculation, fixed-source calculation, burnup calculation and kinetics simulations. Some techniques for geometry treatment, new burnup algorithm, source convergence acceleration, massive tally and parallel calculation, and temperature dependent cross sections processing are researched and implemented in RMC to improve the efficiency. Validation results of criticality calculation, burnup calculation, source convergence acceleration, tallies performance and parallel performance shown in this paper prove the capabilities of RMC in dealing with reactor analysis problems with good performances. (authors)

  17. Reactor Analysis Support Package (RASP). Volume 5. PWR physics analysis guidelines. Final report

    SciTech Connect

    Diamond, D.J.; Lee, R.R.; Mosteller, R.D.; Turinsky, P.J.

    1986-10-01

    The EPRI Reactor Analysis Support Package (RASP) consists of computer codes and documentation for analyzing reactor physics and thermal-hydraulics problems. The principal application of these codes involve fuel management, safety analysis for reload submittals, and general support for reactor operations. This report explains one aspect of RASP; namely, the reactor physics applications for pressurized water reactors. The topics included are the reactor physics models within the RASP codes, the parameters needed for reload safety analysis, the use of reactor physics parameters in each of the transients/accidents that are analyzed for safety analyses and in the interpretation of in-core instrumentation, and the validation of physics models. Although this report refers to the specific codes within RASP, most of the discussion is general enough to be applicable to any calculational methodology.

  18. Reactor Analysis Support Package (RASP). Volume 4. BWR physics analysis guidelines. Final report

    SciTech Connect

    Diamond, D.J.

    1986-10-01

    The EPRI Reactor Analysis Support Package (RASP) consists of computer codes and documentation for analyzing reactor physics and thermal-hydraulics problems. The principal applications of these codes involve fuel management, safety analysis for reload submittals and general support for reactor operations. This report explains one aspect of RASP; namely, the reactor physics applications for boiling water reactors. The topics included are the reactor physics models within the RASP codes, the parameters needed for reload safety analysis, the use of reactor physics parameters in each of the transients/accidents that are analyzed for safety analyses and in the interpretation of in-core instrumentation, and the validation of physics models. Although this report refers to the specific codes within RASP, most of the discussion is general enough to be applicable to any calculational methodology.

  19. How physics instruction impacts students' beliefs about learning physics: A meta-analysis of 24 studies

    NASA Astrophysics Data System (ADS)

    Madsen, Adrian; McKagan, Sarah B.; Sayre, Eleanor C.

    2015-06-01

    In this meta-analysis, we synthesize the results of 24 studies using the Colorado Learning Attitudes about Science Survey (CLASS) and the Maryland Physics Expectations Survey (MPEX) to answer several questions: (1) How does physics instruction impact students' beliefs? (2) When do physics majors develop expert-like beliefs? and (3) How do students' beliefs impact their learning of physics? We report that in typical physics classes, students' beliefs deteriorate or at best stay the same. There are a few types of interventions, including an explicit focus on model-building and (or) developing expertlike beliefs that lead to significant improvements in beliefs. Further, small courses and those for elementary education and nonscience majors also result in improved beliefs. However, because the available data oversamples certain types of classes, it is unclear whether these improvements are actually due to the interventions, or due to the small class size, or student populations typical of the kinds of classes in which these interventions are most often used. Physics majors tend to enter their undergraduate education with more expertlike beliefs than nonmajors and these beliefs remain relatively stable throughout their undergraduate careers. Thus, typical physics courses appear to be selecting students who already have strong beliefs, rather than supporting students in developing strong beliefs. There is a small correlation between students' incoming beliefs about physics and their gains on conceptual mechanics surveys. This suggests that students with more expertlike incoming beliefs may learn more in their physics courses, but this finding should be further explored and replicated. Some unanswered questions remain. To answer these questions, we advocate several specific types of future studies: measuring students' beliefs in courses with a wider range of class sizes, student populations, and teaching methods, especially large classes with very innovative pedagogy and small classes with more typical pedagogy; analysis of the relationship between students' beliefs and conceptual understanding including a wide variety of variables that might influence each; and analysis of large data sets from a variety of classes that track individual students rather than averaging over classes.

  20. Increasing Physical Activity With Mobile Devices: A Meta-Analysis

    PubMed Central

    2012-01-01

    Background Regular physical activity has established physical and mental health benefits; however, merely one quarter of the U.S. adult population meets national physical activity recommendations. In an effort to engage individuals who do not meet these guidelines, researchers have utilized popular emerging technologies, including mobile devices (ie, personal digital assistants [PDAs], mobile phones). This study is the first to synthesize current research focused on the use of mobile devices for increasing physical activity. Objective To conduct a meta-analysis of research utilizing mobile devices to influence physical activity behavior. The aims of this review were to: (1) examine the efficacy of mobile devices in the physical activity setting, (2) explore and discuss implementation of device features across studies, and (3) make recommendations for future intervention development. Methods We searched electronic databases (PubMed, PsychINFO, SCOPUS) and identified publications through reference lists and requests to experts in the field of mobile health. Studies were included that provided original data and aimed to influence physical activity through dissemination or collection of intervention materials with a mobile device. Data were extracted to calculate effect sizes for individual studies, as were study descriptives. A random effects meta-analysis was conducted using the Comprehensive Meta-Analysis software suite. Study quality was assessed using the quality of execution portion of the Guide to Community Preventative Services data extraction form. Results Four studies were of “good” quality and seven of “fair” quality. In total, 1351 individuals participated in 11 unique studies from which 18 effects were extracted and synthesized, yielding an overall weight mean effect size of g = 0.54 (95% CI = 0.17 to 0.91, P = .01). Conclusions Research utilizing mobile devices is gaining in popularity, and this study suggests that this platform is an effective means for influencing physical activity behavior. Our focus must be on the best possible use of these tools to measure and understand behavior. Therefore, theoretically grounded behavior change interventions that recognize and act on the potential of smartphone technology could provide investigators with an effective tool for increasing physical activity. PMID:23171838

  1. High order harmonic generation in rare gases

    SciTech Connect

    Budil, K.S.

    1994-05-01

    The process of high order harmonic generation in atomic gases has shown great promise as a method of generating extremely short wavelength radiation, extending far into the extreme ultraviolet (XUV). The process is conceptually simple. A very intense laser pulse (I {approximately}10{sup 13}-10{sup 14} W/cm{sup 2}) is focused into a dense ({approximately}10{sup l7} particles/cm{sup 3}) atomic medium, causing the atoms to become polarized. These atomic dipoles are then coherently driven by the laser field and begin to radiate at odd harmonics of the laser field. This dissertation is a study of both the physical mechanism of harmonic generation as well as its development as a source of coherent XUV radiation. Recently, a semiclassical theory has been proposed which provides a simple, intuitive description of harmonic generation. In this picture the process is treated in two steps. The atom ionizes via tunneling after which its classical motion in the laser field is studied. Electron trajectories which return to the vicinity of the nucleus may recombine and emit a harmonic photon, while those which do not return will ionize. An experiment was performed to test the validity of this model wherein the trajectory of the electron as it orbits the nucleus or ion core is perturbed by driving the process with elliptically, rather than linearly, polarized laser radiation. The semiclassical theory predicts a rapid turn-off of harmonic production as the ellipticity of the driving field is increased. This decrease in harmonic production is observed experimentally and a simple quantum mechanical theory is used to model the data. The second major focus of this work was on development of the harmonic {open_quotes}source{close_quotes}. A series of experiments were performed examining the spatial profiles of the harmonics. The quality of the spatial profile is crucial if the harmonics are to be used as the source for experiments, particularly if they must be refocused.

  2. Time Harmonic Electromagnetic Field Analysis in Multi-spheres Model by Gumerov's Method of Two Scalar Potentials

    NASA Astrophysics Data System (ADS)

    Hamada, Shoji; Masutani, Keigo; Kobayashi, Tetsuo

    Time harmonic electromagnetic fields in multi-spheres models were calculated by the method of two scalar potentials proposed by Gumerov. The analyzed models were an eccentric two-spheres model and a ten-spheres model including brain core and a pair of eyeballs. The applied fields were a plane wave and a dipole magnetic field, and the frequency was 1.8 or 2.0GHz. The truncation degree p of multipole and local expansion was set to up to 170?200. The peak power density on the x-y plane and the absorbed power in each tissue almost monotonously converged as p increased. It demonstrated the usefulness of the Gumerov's method.

  3. Reply to comments by Henry N. Pollack and David S. Chapman on ``Spherical harmonic analysis of Earth's conductive heat flow''

    NASA Astrophysics Data System (ADS)

    Hamza, V. M.; Cardoso, R. R.; Ponte Neto, C. F.

    2008-04-01

    Pollack and Chapman, hereafter referred to as P&C, argue that: (1) errors arising from lack of quality control in the IHFC database are not important and not properly documented, (2) resolution of spatial patterns in global heat flux distribution should not be represented by spherical harmonics and (3) heat flow in young oceanic crust and global heat loss are better represented by a contested 1-D cooling model than by the data. We disagree and provide additional information that may help clear up such misunderstandings. We also mention briefly the results of a new improved thermal model of the lithosphere that satisfactorily reproduces the main features identified in observational data sets of heat flow and ocean floor bathymetry. Thus, there is no reason to invoke the ad hoc hypothesis of large-scale hydrothermal circulation in the ocean crust.

  4. Harmonic Analysis of Time Variations Observed in the Solar Radio Flux Measured at 810 MHz from 1957 to 2004

    E-print Network

    S. Zieba; J. Maslowski; A. Michalec; G. Michalek; A. Kulak

    2007-01-15

    Long-running measurements of the solar radio flux density at 810 MHz were processed. Based on the least-squares method and using modified periodograms and an iterative technique of fitting and subtracting sinusoids in the time domain, frequency, amplitude, and phase characteristics of any analyzed time series were obtained. Solar cycles 20, 21, and 22 and shorter segments around solar minima and maxima were examined separately. Also, dynamic studies with 405, 810, and 1620 day windows were undertaken. The harmonic representations obtained for all these time series indicate large differences among solar cycles and their segments. We show that the solar radio flux at 810 MHz violates the Gnevyshev-Ohl rule for the pair of cycles 22-23. Analyzing the period 1957-2004, the following spectral periods longer than 1350 days were detected: 10.6, 8.0, 28.0, 5.3, 55.0, 3.9, 6.0, 4.4, and 14.6 yr. For spectral periods between 270 and 1350 days the 11 yr cycle is not recognized. We think that these harmonics form ``impulses of activity'' or a quasi-biennial cycle defined in the Benevolenskaya model of the ``double magnetic cycle.'' The value of about 0.09 is proposed for the interaction parameter (between the low- and high-frequency components) of this model. We confirm the intermittent behavior of the periodicity near 155 days. Correlation coefficients between the radio emission at 810 MHz and sunspot numbers, as well as the radio emission at 2800 MHz calculated for 540 day intervals, depend on the solar cycle phase.

  5. Geomagnetic local and regional harmonic analyses.

    USGS Publications Warehouse

    Alldredge, L.R.

    1982-01-01

    Procedures are developed for using rectangular and cylindrical harmonic analyses in local and regional areas. Both the linear least squares analysis, applicable when component data are available, and the nonlinear least squares analysis, applicable when only total field data are available, are treated. When component data are available, it is advantageous to work with residual fields obtained by subtracting components derived from a harmonic potential from the observed components. When only total field intensity data are available, they must be used directly. Residual values cannot be used. Cylindrical harmonic analyses are indicated when fields tend toward cylindrical symmetry; otherwise, rectangular harmonic analyses will be more advantageous. Examples illustrating each type of analysis are given.-Author

  6. Reactor Physics Methods and Analysis Capabilities in SCALE

    SciTech Connect

    DeHart, Mark D [ORNL; Bowman, Stephen M [ORNL

    2011-01-01

    The TRITON sequence of the SCALE code system provides a powerful, robust, and rigorous approach for performing reactor physics analysis. This paper presents a detailed description of TRITON in terms of its key components used in reactor calculations. The ability to accurately predict the nuclide composition of depleted reactor fuel is important in a wide variety of applications. These applications include, but are not limited to, the design, licensing, and operation of commercial/research reactors and spent-fuel transport/storage systems. New complex design projects such as next-generation power reactors and space reactors require new high-fidelity physics methods, such as those available in SCALE/TRITON, that accurately represent the physics associated with both evolutionary and revolutionary reactor concepts as they depart from traditional and well-understood light water reactor designs.

  7. Physically based groundwater vulnerability assessment using sensitivity analysis methods.

    PubMed

    Beaujean, Jean; Lemieux, Jean-Michel; Dassargues, Alain; Therrien, René; Brouyère, Serge

    2014-01-01

    A general physically based method is presented to assess the vulnerability of groundwater to external pressures by numerical simulation of groundwater flow. The concept of groundwater vulnerability assessment considered here is based on the calculation of sensitivity coefficients for a user-defined groundwater state for which we propose several physically based indicators. Two sensitivity analysis methods are presented: the sensitivity equation method and the adjoint operator method. We show how careful selection of a method can significantly minimize the computational effort. An illustration of the general methodology is presented for the Herten aquifer analog (Germany). This application to a simple, yet insightful, case demonstrates the potential use of this general and physically based vulnerability assessment method to complex aquifers. PMID:24236887

  8. Vibrational analysis of helical poly-L-alanine: Improvement of an empirical harmonic force field for peptides and proteins

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Ho

    1997-08-01

    Vibrational normal modes of regular helical polymers are characterized by A, E1, and E2 symmetry species where A and E1 modes are infrared active and A, E1, and E2 modes are Raman active. For uniaxially oriented ?-poly-L-alanine (?- PLA) samples and their N-deuterated analogues, polarized vibrational (Raman, infrared, and far-infrared) spectra corresponding to each of these optically active symmetry species were measured. Different from previous studies for ?-PLA, in addition to the usual ? I-helix conformation corresponding to the X-ray crystallographically determined structure, our excellent spectral data show another helical conformation occupying about 40% of the PLA sample. Meanwhile, recent advances in computational physics make it possible to compute the vibrational force field by ab initio quantum mechanical methods. In an effort to find a vibrational force field for polypeptides and proteins, based both on the ab initio force fields for small peptides like trans-N-methylacetamide and alanine dipeptides and on the new experimental data, a rigorous vibrational analysis has been done for the ? I-helix first. A compact vibrational formalism up to the cubic anharmonic terms for a regular helix was developed as well as analytic formulas for computation of higher order B-matrix elements. By using this, a more accurate Fermi- Dennison resonance analysis has been possible in the observed amide A band than was the case in previous studies. The direct nonbonded-interaction force constants, introduced to reproduce observed splittings among symmetry species for amide I and II modes, give a more accurate and simple transition-dipole coupling description than does the previous perturbation treatment. All the assigned bands are well reproduced within 5 cm-1 as a result of the least-squares refinement process on the initial force field taken from the ab initio peptide force fields, and the resulting refined force field for the ? I-helix also well explains the observed inelastic neutron scattering spectra for ?-PLA samples. In order to determine the unknown helical structure, the refined force field for the ? I-PLA structure has been applied to the candidate right-handed structures of ? II-, 310-B, and 310-P helices. The 310-helix is the most likely candidate for this additional structure.

  9. Research of rural power grids harmonics monitoring system based on technology of LabVIEW

    NASA Astrophysics Data System (ADS)

    Zhou, Yuhong; Xie, Yunfang; Zhang, Su

    2009-07-01

    A virtual harmonic system based on the development platform of LabVIEW is developed in the article. The basic design idea of this system is virtual instrument(VI). The system is OK to add the harmonic signal collecting from actual electrified wire netting , and also load the platform simulating harmonic signal coming into being. And the on-line harmonic monitoring is carried out through this system, revealing the state of its basic wave and harmonic waves. During the analysis of harmonics, FFT algorithm with high accuracy is used to improve accuracy of harmonics analysis. This system has advantages of better analyzed effection and low cost, and can be extended easily.

  10. Data Analysis in High Energy Physics, Weird or Wonderful

    NASA Astrophysics Data System (ADS)

    Mount, R. P.

    2008-08-01

    I set the scene by outlining the history of SLAC, evolving from a single-purpose high energy physics laboratory, to a laboratory with major strengths in high energy physics (HEP), astronomy, astrophysics and cosmology, plus photon science. I describe the quantum mechanical origins of the statistical challenges in HEP, and how the science has evolved inevitably to require high-energy collisions, huge detectors and painful quantities of data. I follow the evolution and devolution of data-analysis strategies over several decades, looking closely at how technology evolution has influenced analysis strategies and at the demand for vast increases in the random-access performance of storage. Finally I examine cultural and technical contrast that I have observed between HEP computing, computing for astronomy and computing for photon science.

  11. QA/QC requirements for physical properties sampling and analysis

    SciTech Connect

    Innis, B.E.

    1993-07-21

    This report presents results of an assessment of the available information concerning US Environmental Protection Agency (EPA) quality assurance/quality control (QA/QC) requirements and guidance applicable to sampling, handling, and analyzing physical parameter samples at Comprehensive Environmental Restoration, Compensation, and Liability Act (CERCLA) investigation sites. Geotechnical testing laboratories measure the following physical properties of soil and sediment samples collected during CERCLA remedial investigations (RI) at the Hanford Site: moisture content, grain size by sieve, grain size by hydrometer, specific gravity, bulk density/porosity, saturated hydraulic conductivity, moisture retention, unsaturated hydraulic conductivity, and permeability of rocks by flowing air. Geotechnical testing laboratories also measure the following chemical parameters of soil and sediment samples collected during Hanford Site CERCLA RI: calcium carbonate and saturated column leach testing. Physical parameter data are used for (1) characterization of vadose and saturated zone geology and hydrogeology, (2) selection of monitoring well screen sizes, (3) to support modeling and analysis of the vadose and saturated zones, and (4) for engineering design. The objectives of this report are to determine the QA/QC levels accepted in the EPA Region 10 for the sampling, handling, and analysis of soil samples for physical parameters during CERCLA RI.

  12. Left-ventricular systolic and diastolic dyssynchrony as assessed by multi-harmonic phase analysis of gated SPECT myocardial perfusion imaging in patients with end-stage renal disease and normal LVEF

    PubMed Central

    Chen, Ji; Kalogeropoulos, Andreas P.; Verdes, Liudmila; Butler, Javed; Garcia, Ernest V.

    2011-01-01

    Background The purpose of this study was to develop a multi-harmonic phase analysis method to measure diastolic dyssynchrony from conventional gated SPECT myocardial perfusion imaging(MPI) data and to compare it with systolic dyssynchrony in normal subjects and in patients with end-stage renal disease (ESRD) and normal left-ventricular ejection fraction (LVEF). Methods 121 consecutive patients with ESRD and normal LVEF and 30 consecutive normal controls were enrolled. Diastolic dyssynchrony parameters were calculated using 3-harmonic phase analysis. Systolic dyssynchrony parameters were calculated using the established 1-harmonic phase analysis. Results The systolic and diastolic dyssynchrony parameters were correlated, but significantly different in both control and ESRD groups, indicating they were physiologically related but measured different LV mechanisms. The systolic and diastolic dyssynchrony parameters were each significantly different between the control and the ESRD groups. Significant systolic and diastolic dyssynchrony were found in 47% and 65% of the entire ESRD group. Conclusion Multi-harmonic phase analysis has been developed to assess diastolic dyssynchrony, which measured a new LV mechanism of regional function from gated SPECT MPI and showed a significantly higher prevalence rate than systolic dyssynchrony in patients with ESRD and normal LVEF. PMID:21229401

  13. Data Preservation and Long Term Analysis in High Energy Physics

    E-print Network

    David M. South

    2012-06-22

    Several important and unique experimental high-energy physics programmes at a variety of facilities are coming to an end, including those at HERA, the B-factories and the Tevatron. The wealth of physics data from these experiments is the result of a significant financial and human effort, and yet until recently no coherent strategy existed for data preservation and re-use. To address this issue, an inter-experimental study group on data preservation and long-term analysis in high-energy physics was convened at the end of 2008, publishing an interim report in 2009. The membership of the study group has since expanded, including the addition of the LHC experiments, and a full status report has now been released. This report greatly expands on the ideas contained in the original publication and provides a more solid set of recommendations, not only concerning data preservation and its implementation in high-energy physics, but also the future direction and organisational model of the study group. The main messages of the status report were presented for the first time at the 2012 International Conference on Computing in High Energy and Nuclear Physics and are summarised in these proceedings.

  14. Harmonic leakage and image quality degradation in tissue harmonic imaging

    Microsoft Academic Search

    Che-Chou Shen; Pai-Chi Li

    2001-01-01

    Image quality degradation caused by harmonic leakage was studied for finite amplitude distortion-based harmonic imaging. Various sources of harmonic leakage, including transmit waveform, signal bandwidth, and system nonlinearity, were investigated using both simulations and hydrophone measurements. Effects of harmonic leakage in the presence of sound velocity inhomogeneities were also considered. Results indicated that sidelobe levels of the harmonic beam pattern

  15. Lab 5: Damped simple harmonic motion Simple harmonic oscillation

    E-print Network

    Glashausser, Charles

    Lab 5: Damped simple harmonic motion · Simple harmonic oscillation · Damped harmonic oscillation;Friction: retarding motion (energy dissipation) Damped simple harmonic oscillation 1 2 Hooke's law: Damping 381 Mechanics #12;Ideal case: no friction Simple harmonic oscillation Hooke's law: Newton's 2nd law: F

  16. Signature of a non-harmonic potential as revealed from a consistent shape and fluctuation analysis of an adherent membrane

    E-print Network

    Daniel Schmidt; Cornelia Monzel; Timo Bihr; Rudolf Merkel; Udo Seifert; Kheya Sengupta; Ana-Sun?ana Smith

    2014-03-28

    The interaction of fluid membranes with a scaffold, which can be a planar surface or a more complex structure, is intrinsic to a number of systems - from artificial supported bilayers and vesicles to cellular membranes. In principle, these interactions can be either discrete and protein mediated, or continuous. In the latter case, they emerge from ubiquitous intrinsic surface interaction potentials as well as nature-designed steric contributions of the fluctuating membrane or from the polymers of the glycocalyx. Despite the fact that these nonspecific potentials are omnipresent, their description has been a major challenge from experimental and theoretical points of view. Here we show that a full understanding of the implications of the continuous interactions can be achieved only by expanding the standard superposition models commonly used to treat these types of systems, beyond the usual harmonic level of description. Supported by this expanded theoretical framework, we present three independent, yet mutually consistent, experimental approaches to measure the interaction potential strength and the membrane tension. Upon explicitly taking into account the nature of shot noise as well as of finite experimental resolution, excellent agreement with the augmented theory is obtained, which finally provides a coherent view of the behavior of the membrane in a vicinity of a scaffold.

  17. Even harmonic lasing

    SciTech Connect

    Schmitt, M.J.

    1991-01-01

    Operation of a free-electron laser at harmonics of the fundamental frequency is explored with the numerical simulation code HELEX. This code includes coupling to the harmonics caused by misalignment of the electrons with the optical beam and coupling due to transverse gradients. Albeit weak, the transverse gradients produce the dominant coupling of the electrons to the even-harmonic light. Even-harmonic lasing occurs in a TEM{sub 0,2m+1}-like mode where the field on axis is zero. As bunching of the electron beam progresses, radiation at the higher odd harmonics is suppressed owing to the absence of higher-order odd-harmonic Fourier components in the bunch. Growth of the even-harmonic power from small signal requires suppression of competing harmonics (including the fundamental) that have higher gain. Lasing at an even harmonic has yet to be experimentally demonstrated in an open resonator (i.e. optical cavity). Strategies to make such an experiment possible are discussed. 9 refs., 5 figs., 1 tab.

  18. Positioning Ideas: Creating and Relating Physics Identities Through Video Analysis

    NASA Astrophysics Data System (ADS)

    Harlow, Danielle Boyd; Swanson, Lauren H.

    2009-11-01

    Prior research has documented that analyzing video of children learning science aids pre-service teachers in developing physics knowledge and deepens their understanding of the learning process. Research on video analysis in teacher education suggests that the primary value of such tasks comes not from watching the video, but from the subsequent discussions. We questioned whether similar advantages would be evident when participants watched and analyzed video clips via online threaded discussions. We found that participants used the video clips as a mediating tool to position their own current ideas about physics topics with respect to their prior understandings as well as to ideas articulated by the students in the video clips. We discuss the study findings and affordances and limitations of online discussion formats.

  19. Introduction to the Space Physics Analysis Network (SPAN)

    NASA Technical Reports Server (NTRS)

    Green, J. L. (editor); Peters, D. J. (editor)

    1985-01-01

    The Space Physics Analysis Network or SPAN is emerging as a viable method for solving an immediate communication problem for the space scientist. SPAN provides low-rate communication capability with co-investigators and colleagues, and access to space science data bases and computational facilities. The SPAN utilizes up-to-date hardware and software for computer-to-computer communications allowing binary file transfer and remote log-on capability to over 25 nationwide space science computer systems. SPAN is not discipline or mission dependent with participation from scientists in such fields as magnetospheric, ionospheric, planetary, and solar physics. Basic information on the network and its use are provided. It is anticipated that SPAN will grow rapidly over the next few years, not only from the standpoint of more network nodes, but as scientists become more proficient in the use of telescience, more capability will be needed to satisfy the demands.

  20. HARMONIC FUNCTIONS WITH POLYNOMIAL GROWTH

    E-print Network

    Minicozzi, William

    HARMONIC FUNCTIONS WITH POLYNOMIAL GROWTH TOBIAS 1 1. Harmonic functions with polynomial growth on cones 5 2. Tools to study the growth of harmonic functions on manifolds 13 3. Lower bound of the frequency

  1. Harmonic morphisms and shear-free ray congruences

    Microsoft Academic Search

    P. Baird; J. C. Wood

    2003-01-01

    We describe the relationship between complex-valued harmonic morphisms from Minkowski 4-space} and the shear-free ray congruences of mathematical physics. Then we show how a horizontally conformal submersion on a domain of Euclidean 3-space gives the boundary values at infinity of a complex-valued harmonic morphism on hyperbolic 4-space.

  2. A New Technique for Detection of High Impedance Faults in Power Distribution System Based on Current Harmonic Analysis

    Microsoft Academic Search

    M. Jannati; L. Eslami

    In every distribution system, physical contact between conductors of a phase and substances around them like trees, walls of the buildings and surfaces below them, always is possible. These conditions, known as High Impedance Faults (HIFs), can lead to death due to electricity congestion, burning or ignition via arc or heat of the substances. On the other hand, the whole

  3. Relativistic harmonic oscillator revisited

    SciTech Connect

    Bars, Itzhak [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-2535 (United States)

    2009-02-15

    The familiar Fock space commonly used to describe the relativistic harmonic oscillator, for example, as part of string theory, is insufficient to describe all the states of the relativistic oscillator. We find that there are three different vacua leading to three disconnected Fock sectors, all constructed with the same creation-annihilation operators. These have different spacetime geometric properties as well as different algebraic symmetry properties or different quantum numbers. Two of these Fock spaces include negative norm ghosts (as in string theory), while the third one is completely free of ghosts. We discuss a gauge symmetry in a worldline theory approach that supplies appropriate constraints to remove all the ghosts from all Fock sectors of the single oscillator. The resulting ghost-free quantum spectrum in d+1 dimensions is then classified in unitary representations of the Lorentz group SO(d,1). Moreover, all states of the single oscillator put together make up a single infinite dimensional unitary representation of a hidden global symmetry SU(d,1), whose Casimir eigenvalues are computed. Possible applications of these new results in string theory and other areas of physics and mathematics are briefly mentioned.

  4. Management of the Space Physics Analysis Network (SPAN)

    NASA Technical Reports Server (NTRS)

    Green, James L.; Thomas, Valerie L.; Butler, Todd F.; Peters, David J.; Sisson, Patricia L.

    1990-01-01

    Here, the purpose is to define the operational management structure and to delineate the responsibilities of key Space Physics Analysis Network (SPAN) individuals. The management structure must take into account the large NASA and ESA science research community by giving them a major voice in the operation of the system. Appropriate NASA and ESA interfaces must be provided so that there will be adequate communications facilities available when needed. Responsibilities are delineated for the Advisory Committee, the Steering Committee, the Project Scientist, the Project Manager, the SPAN Security Manager, the Internetwork Manager, the Network Operations Manager, the Remote Site Manager, and others.

  5. Multi-Physics Analysis of the Fermilab Booster RF Cavity

    SciTech Connect

    Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.; /Fermilab

    2012-05-14

    After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.

  6. Texture analysis of collagen second-harmonic generation images based on local difference local binary pattern and wavelets differentiates human skin abnormal scars from normal scars

    NASA Astrophysics Data System (ADS)

    Liu, Yao; Zhu, Xiaoqin; Huang, Zufang; Cai, Jianyong; Chen, Rong; Xiong, Shuyuan; Chen, Guannan; Zeng, Haishan

    2015-01-01

    Quantitative methods for noninvasive diagnosis of scars are a challenging issue in medicine. This work aims to implement a texture analysis method for quantitatively discriminating abnormal scars from normal scars based on second-harmonic generation (SHG) images. A local difference local binary pattern (LD-LBP) operator combined with a wavelet transform was explored to extract diagnosis features from scar SHG images that were related to the alteration in collagen morphology. Based on the quantitative parameters including the homogeneity, directional and coarse features in SHG images, the scar collagen SHG images were classified into normal or abnormal scars by a support vector machine classifier in a leave-one-out cross-validation procedure. Our experiments and data analyses demonstrated apparent differences between normal and abnormal scars in terms of their morphological structure of collagen. By comparing with gray level co-occurrence matrix, wavelet transform, and combined basic local binary pattern and wavelet transform with respect to the accuracy and receiver operating characteristic analysis, the method proposed herein was demonstrated to achieve higher accuracy and more reliable classification of SHG images. This result indicated that the extracted texture features with the proposed method were effective in the classification of scars. It could provide assistance for physicians in the diagnostic process.

  7. The structure of subcritical and supercritical methanol by neutron diffraction, empirical potential structure refinement, and spherical harmonic analysis

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Toshio; Benmore, C. J.; Soper, A. K.

    2000-05-01

    Pulsed neutron diffraction with isotope substitution on the hydroxyl hydrogens (H) is used to study the structure of methanol in two supercritical conditions (253 °C, 117.7 MPa, 0.700 g cm-3 and 253 °C, 14.3 MPa, 0.453 g cm-3) as well as a subcritical state (202 °C, 73.7 MPa, 0.700 g cm-3) (Tc=240 °C, Pc=8.1 MPa, ?c=0.272 g cm-3 for methanol). From three experiments on CD3OD, CD3OH, and a CD3O(H0.28+D0.72) mixture at the three thermodynamic states, the composite partial structure factors and pair correlation functions, XX, XH, and HH, are derived, where X represents a weighted sum of correlations from carbon (C), oxygen (O), and methyl hydrogen (M) atoms on the methanol molecule. The data are used in an empirical potential structure refinement (EPSR) computer simulation of methanol at the three thermodynamics states. Model distributions of molecules consistent with these data are used to estimate the individual site-site radial distribution functions, the coefficients of the spherical harmonic expansion of the orientational pair correlation function, the details of hydrogen bonding, and the three-dimensional structure of clusters formed in subcritical and supercritical methanol. In both subcritical and supercritical states of moderate density, the hydrogen bonds remain, with the average number of hydrogen bonds of 1.6±0.1 per molecule and the average chain-length of 3.1±0.4 molecules, which are less than the 1.77±0.07 per molecule and 5.5±1.0 molecules, respectively, found under ambient conditions; however, in the subcritical and supercritical methanol at moderate density the hydrogen bonds are mostly associated with clusters of 3-5 methanol molecules, in contrast with ambient methanol in which methanol molecules are involved in a nonlinear hydrogen bonded chain structure. In the low-density supercritical methanol, the large clusters are broken to generate monomers or small oligomers; the average number of hydrogen bonds per molecule decreases to 1.0±0.1, and the chain-length is 1.8±0.2 with a maximum length up to 7. The present results are compared with those recently obtained by molecular dynamics simulations, NMR, and Raman scattering of supercritical methanol.

  8. Spherical Harmonic Analysis of the PSCz Galaxy Catalogue: Redshift distortions and the real-space power spectrum

    E-print Network

    H. Tadros; W. E. Ballinger; A. N. Taylor; A. F. Heavens; G. Efstathiou; W. Saunders; C. S. Frenk; O. Keeble; R. McMahon; S. J. Maddox; S. Oliver; M. Rowan-Robinson; W. J. Sutherland S. D. M. White

    1999-01-25

    We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. The PSCz redshift survey has almost all-sky coverage and includes IRAS galaxies to a flux limit of 0.6 Jy. Using maximum likelihood methods to examine (to first order) the distortion of the galaxy pattern due to redshift coordinates, we have measured the parameter \\beta= \\Omega^{0.6}/b. We also simultaneously measure (a) the undistorted amplitude of perturbations in the galaxy distribution when a parameterised power spectrum is assumed, or (b) the shape and amplitude of the real-space power spectrum if the band-power in a set of passbands is measured in a step- wise fashion. These methods are extensively tested on a series of CDM, \\Lambda CDM and MDM simulations and are found to be unbiased. We obtain consistent results for the subset of the PSCz catalogue with flux above 0.75 Jy but inclusion of galaxies to the formal flux limit of the catalogue gives variations which are larger than our internal errors. For the 0.75 Jy catalogue we find, in the case of a parameterised power spectrum, \\beta=0.58\\pm0.26 and the amplitude of the real space power measured at wavenumber k=0.1 h/Mpc is \\Delta_{0.1}=0.42 \\pm 0.03. Freeing the shape of the power spectrum we find that \\beta=0.47\\pm 0.16 (conditional error), and \\Delta_{0.1}=0.47 \\pm 0.03. The shape of the real-space power spectrum is consistent with a \\Gamma= 0.2 CDM-like shape parameter, but does not strongly rule out a number of other models. Finally by combining our estimate of the amplitude of galaxy clustering and the distortion parameter we find the amplitude of mass fluctuations on a scale k=0.1 \\hmpc is \\Delta_\\rho = 0.24 \\Omega_0^{-0.6}$, with an uncertainty of 50%.

  9. Simulated, Emulated, and Physical Investigative Analysis (SEPIA) of networked systems.

    SciTech Connect

    Burton, David P.; Van Leeuwen, Brian P.; McDonald, Michael James; Onunkwo, Uzoma A.; Tarman, Thomas David; Urias, Vincent E.

    2009-09-01

    This report describes recent progress made in developing and utilizing hybrid Simulated, Emulated, and Physical Investigative Analysis (SEPIA) environments. Many organizations require advanced tools to analyze their information system's security, reliability, and resilience against cyber attack. Today's security analysis utilize real systems such as computers, network routers and other network equipment, computer emulations (e.g., virtual machines) and simulation models separately to analyze interplay between threats and safeguards. In contrast, this work developed new methods to combine these three approaches to provide integrated hybrid SEPIA environments. Our SEPIA environments enable an analyst to rapidly configure hybrid environments to pass network traffic and perform, from the outside, like real networks. This provides higher fidelity representations of key network nodes while still leveraging the scalability and cost advantages of simulation tools. The result is to rapidly produce large yet relatively low-cost multi-fidelity SEPIA networks of computers and routers that let analysts quickly investigate threats and test protection approaches.

  10. Transformation of spherical harmonic coefficients to ellipsoidal harmonic coefficients

    Microsoft Academic Search

    D. Dechambre; D. J. Scheeres

    2002-01-01

    Analytical expressions linking spherical harmonics gravity field expansions with ellipsoidal harmonics gravity field expansions are developed. Certain symmetries and simplifications for the transformation between the two are noted. Using the expressions, a numerical approach is developed and applied for the computation of ellipsoidal harmonic gravity coefficients using spherical harmonics coefficients as inputs. This method can be used to transform a

  11. Transformation of spherical harmonic coecients to ellipsoidal harmonic coecients

    Microsoft Academic Search

    D. Dechambre; D. J. Scheeres

    2002-01-01

    Analytical expressions linking spherical harmonics gravity eld expansions with ellipsoidal harmonics gravity eld expansions are developed. Certain symmetries and simplications for the transformation between the two are noted. Using the expressions, a numerical approach is developed and applied for the computation of ellipsoidal harmonic gravity coecients using spherical harmonics coecients as inputs. This method can be used to transform a

  12. A Proposed Cost-benefit Analysis Model for Physical Form Analysis for a Futuristic Submarine Decision Support System

    E-print Network

    Cummings, Mary "Missy"

    A Proposed Cost-benefit Analysis Model for Physical Form Analysis for a Futuristic Submarine for Physical Form Analysis for a Futuristic Submarine Decision Support System by Dhiman Bhattacharjee Submitted for submarine commanders managing multiple unmanned underwater vehicles, follows an integrated systems

  13. The Coupled Harmonic Oscillator: Not Just for Seniors Anymore.

    ERIC Educational Resources Information Center

    Preyer, Norris W.

    1996-01-01

    Presents experiments that use Microcomputer Based Laboratory (MBL) techniques to enable freshmen physics students to investigate complex systems, such as nonlinear oscillators or coupled harmonic oscillators, at a level appropriate for an independent project. (JRH)

  14. COMBINATION OF PHYSICAL-ORGANIC AND THEORETICAL METHODS IN ELECTRONIC STRUCTURE ANALYSIS. OPPOSING

    E-print Network

    Glaser, Rainer

    COMBINATION OF PHYSICAL-ORGANIC AND THEORETICAL METHODS IN ELECTRONIC STRUCTURE ANALYSIS. OPPOSING for electronic structure analysis. In this context, we will address a central question in physical on electronic structure. The interpretation of the physical-organic data often is difficult and presents

  15. The effects of static quartic anharmonicity on the quantum dynamics of a linear oscillator with time-dependent harmonic frequency: Perturbative analysis and numerical calculations

    SciTech Connect

    Sarkar, P.; Bhattacharyya, S.P. [Indian Association for the Cultivation of Science, Calcutta (India)

    1995-06-15

    The effects of quartic anharmonicity on the quantum dynamics of a linear oscillator with time-dependent force constant (K) or harmonic frequency ({omega}) are studied both perturbatively and numerically by the time-dependent Fourier grid Hamiltonian method. In the absence of anharmonicity, the ground-state population decreases and the population of an accessible excited state (k = 2.4, 6 ... ) increases with time. However, when anharmonicity is introduced, both the ground- and excited-state populations show typical oscillations. For weak coupling, the population of an accessible excited state at a certain instant of time (short) turns out to be a parabolic function of the anharmonic coupling constant ({lambda}), when all other parameters of the system are kept fixed. This parabolic nature of the excited-state population vs. the {lambda} profile is independent of the specific form of the time dependence of the force constant, K{sub t}. However, it depends upon the rate at which K{sub t} relaxes. For small anharmonic coupling strength and short time scales, the numerical results corroborate expectations based on the first-order time-dependent perturbative analysis, using a suitably repartitioned Hamiltonian that makes H{sub 0} time-independent. Some of the possible experimental implications of our observations are analyzed, especially in relation to intensity oscillations observed in some charge-transfer spectra in systems in which the dephasing rates are comparable with the time scale of the electron transfer. 21 refs., 7 figs., 1 tab.

  16. Mellin Transforms and Asymptotics: Harmonic Sums

    Microsoft Academic Search

    Philippe Flajolet; Xavier Gourdon; Philippe Dumas

    1995-01-01

    This survey presents a unified and essentially self-contained approach to the asymptotic analysis of a large class of sums that arise in combinatorial mathematics, discrete probabilistic models, and the average-case analysis of algorithms. It relies on the Mellin transform, a close relative of the integral transforms of Laplace and Fourier. The method applies to harmonic sums that are superpositions of

  17. Integrating the Timing Analysis of Pipelining and Instruction Caching * Christopher A. Healy, David B. Whalley Marion G. Harmon

    E-print Network

    Harmon, Marion

    Integrating the Timing Analysis of Pipelining and Instruction Caching * Christopher A. Healy, David contain pipelines and caches. While both features provide significant performance advantages, they also pose problems for predicting execu­ tion time of code segments in real­time systems. Pipeline hazards

  18. M -theory on AdS_4 x Q^{111}: The complete Osp(2|4) x SU(2) x SU(2) x SU(2) spectrum from harmonic analysis

    E-print Network

    P. Merlatti

    2000-12-18

    In this paper by means of harmonic analysis we derive the complete spectrum of Osp(2|4) x SU(2) x SU(2) x SU(2) multiplets that one obtains compactifying D=11 supergravity on the homogeneous space Q^{111}. In particular we analyze the structure of the short multiplets and compare them with the corresponding composite operators of the N=2 conformal field theory dual to such a compactification, found in a previous publication. We get complete agreement between the quantum numbers of the supergravity multiplets on one side and those of the conformal operators on the other side, confirming the structure of the conjectured SCFT. However the determination of the actual spectrum by harmonic analysis teaches us a lot more: indeed we find out which multiplets are present for each representation of the isometry group, how many they are, the exact values of the hypercharge and of the energy for each multiplet.

  19. Fault Detection and Diagnostics for Non-Intrusive Monitoring Using Motor Harmonics

    E-print Network

    Orji, Uzoma A.

    Harmonic analysis of motor current has been used to track the speed of motors for sensorless control. Algorithms exist that track the speed of a motor given a dedicated stator current measurement, for example. Harmonic ...

  20. Harmonic analysis of the fluorescence response of bimane adducts of colicin E1 at helices 6, 7, and 10.

    PubMed

    Ho, Derek; Lugo, Miguel R; Merrill, A Rod

    2013-02-15

    The pre-channel state of helices 6, 7, and 10 (Val(447)-Gly(475) and Ile(508)-Ile(522)) of colicin E1 was investigated by a site-directed fluorescence labeling technique. A total of 44 cysteine variants were purified and covalently labeled with monobromobimane fluorescent probe. A variety of fluorescence properties of the bimane fluorophore were measured for both the soluble and membrane-bound states of the channel peptide, including the fluorescence emission maximum, fluorescence anisotropy, and membrane bilayer penetration depth. Using site-directed fluorescence labeling combined with our novel helical periodicity analysis method, the data revealed that helices 6, 7, and 10 are separate amphipathic ?-helices with a calculated periodicity of T = 3.34 ± 0.08 for helix 6, T = 3.56 ± 0.03 for helix 7, and T = 2.99 ± 0.12 for helix 10 in the soluble state. In the membrane-bound state, the helical periodicity was determined to be T = 3.00 ± 0.15 for helix 6, T = 3.68 ± 0.03 for helix 7, and T = 3.47 ± 0.04 for helix 10. Dual fluorescence quencher analysis showed that both helices 6 and 7 adopt a tilted topology that correlates well with the analysis based on the fluorescence anisotropy profile. These data provide further support for the umbrella model of the colicin E1 channel domain. PMID:23264635

  1. A Utopian View of Space Plasma Physics Data Analysis (Invited)

    NASA Astrophysics Data System (ADS)

    Sibeck, D. G.

    2010-12-01

    In an ideal space physics plasma data environment, I would go to the internet, enter names and types of data sets that I need, find them immediately via a google-like search, download them into a folder, and then use my all-purpose platform-independent software to immediately begin plotting, analyzing, and combining data sets from multiple sources, instruments, and spacecraft without ever writing any software myself or even looking inside the files. In order for this to happen, the data sets would have to be in readily recognizable standardized formats, described in sufficient detail to enable rapid discovery, and accompanied by metadata enabling the software to work. The display and analysis tools would have to include the full range of features needed for data visualization, including the construction of parameters or plots combining observations from multiple sources.

  2. Qualitative Analysis of Distributed Physical Systems with Applications to Control Synthesis \\Lambda

    E-print Network

    Bailey-Kellogg, Chris

    Qualitative Analysis of Distributed Physical Systems with Applications to Control Synthesis \\Lambda­ ature distribution, air flow, and acoustic waves, are described as continuous, distributed parameter fields. Analyzing and controlling these physical processes and systems are common tasks in many

  3. Analysis of Radon Decay Data and its Implications for Physics, Geophysics, and Solar Physics.

    NASA Astrophysics Data System (ADS)

    Sturrock, Peter A.; Fischbach, E.; Jenkins, J. H.; Steinitz, G.

    2012-05-01

    We present an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between January 28 2007 and May 10 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis also reveals a number of periodicities, notably at 11.2 year-1 and 12.5 year-1, which we have found in other nuclear-decay data --including data acquired at the Brookhaven National Laboratory and the Physiklisch-Technische Bundesanstalt-- which we attribute to a solar influence. A distinct property of the GSI results is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. We speculate on possible interpretations of this curious result. Solar neutrinos remain our prime suspect as the agent responsible for beta-decay anomalies. These results have implications for physics (that nuclear decay rates are not constant and may be stimulated); for geophysics (that the variability of radon measurements cannot be ascribed entirely to atmospheric and solid-earth processes); and for solar physics (that the Sun contains an inner tachocline, separating a slowly rotating core from the radiative zone, which has properties similar to those of the outer tachocline separating the radiative zone from the convection zone). This work was supported by DOE grant DE-AC-02-76ER071428.

  4. PHYSICAL REVIEW B 89, 024102 (2014) Ultrafast surface strain dynamics in MnAs thin films observed with second harmonic generation

    E-print Network

    Van Driel, Henry M.

    2014-01-01

    PHYSICAL REVIEW B 89, 024102 (2014) Ultrafast surface strain dynamics in MnAs thin films observed strain in 150 and 190-nm thin films of MnAs grown epitaxially on GaAs(001). The p-polarized SHG signal the surface temperature by tens of degrees. For a film at -20 C the strain reaches a minimum value in 10 ps

  5. A stochastic approach to the harmonic map heat flow on manifolds with time-dependent Riemannian metric

    E-print Network

    Thalmaier, Anton

    A stochastic approach to the harmonic map heat flow on manifolds with time-dependent Riemannian situations. Keywords: Harmonic map heat flow, stochastic analysis on manifolds, time-dependent geometry AMS-time harmonic maps which by time reversal provide solutions to the harmonic map heat flow (or nonlinear heat

  6. Reduced-Reference Video Quality Assessment Using Discriminative Local Harmonic Strength With Motion Consideration

    Microsoft Academic Search

    Irwan Prasetya Gunawan; Mohammed Ghanbari

    2008-01-01

    This paper presents a reduced-reference objective picture quality measurement tool of compressed video. We have used a discriminative analysis of harmonic strength computed from edge-detected pictures to create harmonics gain and loss information that could be associated with the picture. The harmonics gain\\/loss are derived through the harmonic analysis of the compressed and source pictures to be incorporated in the

  7. Minor physical anomalies in schizophrenia: a meta-analysis

    PubMed Central

    Weinberg, Seth M.; Jenkins, Elizabeth A.; Marazita, Mary L.; Maher, Brion S.

    2008-01-01

    Numerous studies report an increased frequency of minor physical anomalies (MPAs) in schizophrenic individuals compared with controls. However, these studies vary considerably regarding the magnitude of the case-control disparity and the topographical distribution of the anomalies. A meta-analysis was carried out on the existing MPA literature in an effort to better understand the relationship between MPAs and schizophrenia. Following a literature search, 13 studies were identified that met our inclusion criteria. Mean total MPA scores were available for 11 of these studies, whereas only seven studies provided regional MPA scores. For both the total MPA and regional MPA analyses, pooled effect sizes (Hedges' g and pooled odds ratios, respectively) were calculated along with tests of heterogeneity. For the total MPA analyses, a meta-regression approach was used to explore the relationship between possible moderator variables (e.g., number of MPA scale items) and effect size heterogeneity. The magnitude of the pooled effect size for the total MPA scores was high (1.131; p < 0.001), indicating significantly more overall MPAs in schizophrenic individuals. Significant effect size heterogeneity was present (p < 0.001); however, this heterogeneity could not be explained by any of the included moderator variables. The regional MPA analysis revealed significantly increased MPAs in all six anatomical regions (p < 0.05), although the pooled odds ratios for these regions did not differ significantly from one another. These results suggest a lack of regional specificity for MPAs in schizophrenia. PMID:17079117

  8. Destructive physical analysis of degraded quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Sin, Y.; Lingley, Z.; Brodie, M.; Presser, N.; Moss, S. C.; Kirch, J.; Chang, C. C.; Boyle, C.; Mawst, L. J.; Botez, D.; Lindberg, D.; Earles, T.

    2015-03-01

    Remarkable progress made in quantum cascade lasers (QCLs) has led them to find an increasing number of applications in remote sensing, chemical sensing, and free space communications, in addition to potential space applications. However, little has been reported on reliability and failure modes of QCLs although it is crucial to understand failure modes and underlying degradation mechanisms in developing QCLs that meet lifetime requirements for space missions. Focused ion beam (FIB) techniques have been employed to investigate failure modes in various types of laser diodes. Our group has also used FIB to study failure modes in single-mode and multi-mode InGaAs-AlGaAs strained QW lasers, but few groups have used this technique to investigate failure modes in QCLs. In our study, we report on destructive physical analysis (DPA) of degraded InGaAs-InAlAs QCLs using FIB and high-resolution TEM techniques. The active region of QCLs that we studied consisted of two-23 stage layers of InGaAs-InAlAs separated by a 0.5 ?m thick InP spacer layer for 8.4?m QCLs and 30-stage layers of lattice-matched InGaAs-InAlAs heterostructure for 4.7?m QCLs. The MOVPE-grown laser structures were fabricated into deep-etched ridge waveguide QCLs. L-I-V-spectral characteristics were measured at RT under pulsed operation. Our 8.4?m QCLs with as-cleaved and HR-coated facets showed a laser threshold of 1.7 A and a threshold voltage of 13 V at RT, whereas our 4.7?m QCLs without facet coating showed threshold currents of 320 - 400 mA and threshold voltages of 13 - 13.5V. Failures were generated via short-term tests of QCLs. FIB systems were used to study the damage area on the front facet and also to prepare TEM cross sections at different locations along the waveguide for defect and chemical analyses using a HR-TEM. In contrast to the COMD damaged area showing as a blister on the front facet of QW lasers, the damaged area of QCLs was significantly extended into the InP substrate due to a much less absorption of lasing photons in QCLs. Our detailed destructive physical analysis results are reported including defect, structural, and chemical analysis results from degraded QCLs.

  9. Selection rules for harmonic generation in solids

    NASA Astrophysics Data System (ADS)

    Moiseyev, Nimrod

    2015-05-01

    High-order harmonic generation (HHG) in a bulk crystal was first observed in 2011 [S. Ghimire, A. D. DiChiara, E. Sistrunk, P. Agostini, L. F. DiMauro, and D. A. Reis, Nat. Phys. 7, 138 (2011), 10.1038/nphys1847]. Only odd-order harmonics were observed as expected on the basis of the selection rules in solids, which were derived when only the interband currents were taken into consideration. Here we study HHG in solids when the intraband currents are taken into consideration as well. We show that the dynamical selection rules are broken in solids and the possibility of generation of even-order harmonics cannot be excluded on the basis of the dynamical symmetry analysis. However, a simple analysis of the expression we obtained for the amplitude of the emitted high-order harmonics shows, without the need to carry out numerical calculations, that the even-order harmonics are suppressed due to the localization of the field-free one-electron density probability on the atoms in the solids.

  10. SU(4) harmonic superspace and supersymmetric gauge theory

    E-print Network

    B. M. Zupnik

    2014-10-10

    We consider the harmonic-superspace formalism in the $N=4$ supersymmetry using the $SU(4)/SU(2)\\times SU(2)\\times U(1)$ harmonics which was earlier applied to the abelian gauge theory. The N=4 non-abelian constraints in a standard superspace are reformulated as the harmonic-superspace equations for two basic analytic superfields: the independent superfield strength W of a dimension 1 and the dimensionless harmonic gauge 4-prepotential V having the $U(1)$ charge 2. These constraint equations I manifestly depend on the Grassmann coordinates $\\theta$, although they are covariant under the unusual N=4 supersymmetry transformations. We analyze an alternative harmonic formalism of the supergauge theory for two unconstrained nonabelian analytic superfields W and V. The gauge-invariant action A(W,V) in this formalism contains $\\theta$ factors in each term, it is invariant under the $SU(4)$ automorphism group. In this model, the interaction of two infinite-dimensional N=4 supermultiplets with the physical and auxiliary fields arises at the level of component fields. The action A(W,V) generate analytic equations of motion II alternative to the harmonic-superspace superfield constraints I. Both sets of equations give us the equivalent equations for the physical component fields of the $N=4$ gauge supermultiplet, they connect auxiliary and physical fields of two superfields. The nonlinear effective interaction of the abelian harmonic superfield W is constructed.

  11. Adjoint Sensitivity Analysis of Orbital Mechanics: Application to Computations of Observables' Partials with Respect to Harmonics of the Planetary Gravity Fields

    NASA Technical Reports Server (NTRS)

    Ustinov, Eugene A.; Sunseri, Richard F.

    2005-01-01

    An approach is presented to the inversion of gravity fields based on evaluation of partials of observables with respect to gravity harmonics using the solution of adjoint problem of orbital dynamics of the spacecraft. Corresponding adjoint operator is derived directly from the linear operator of the linearized forward problem of orbital dynamics. The resulting adjoint problem is similar to the forward problem and can be solved by the same methods. For given highest degree N of gravity harmonics desired, this method involves integration of N adjoint solutions as compared to integration of N2 partials of the forward solution with respect to gravity harmonics in the conventional approach. Thus, for higher resolution gravity models, this approach becomes increasingly more effective in terms of computer resources as compared to the approach based on the solution of the forward problem of orbital dynamics.

  12. Cardiovascular risk profile: Cross-sectional analysis of motivational determinants, physical fitness and physical activity

    Microsoft Academic Search

    Barbara Sassen; Gerjo Kok; Herman Schaalma; Henri Kiers; Luc Vanhees

    2010-01-01

    BACKGROUND: Cardiovascular risk factors are associated with physical fitness and, to a lesser extent, physical activity. Lifestyle interventions directed at enhancing physical fitness in order to decrease the risk of cardiovascular diseases should be extended. To enable the development of effective lifestyle interventions for people with cardiovascular risk factors, we investigated motivational, social-cognitive determinants derived from the Theory of Planned

  13. Physical Disability on Children's Television Programming: A Content Analysis

    ERIC Educational Resources Information Center

    Bond, Bradley J.

    2013-01-01

    Research Findings: Media representations of physical disability can influence the attitudes of child audiences. In the current study, the depiction of physical disability was analyzed in more than 400 episodes of children's television programming to better understand how media depict physical disability to children and, in turn, how exposure may…

  14. Re-Conceiving Ability in Physical Education: A Social Analysis

    ERIC Educational Resources Information Center

    Wright, Jan; Burrows, Lisette

    2006-01-01

    In this paper we explore how "ability" is currently conceptualised in physical education and with what effects for different groups of young people. We interrogate approaches to theorising ability in physical education that draw on sociological and phenomenological "foundations" together with notions of ability as "physical" and "cultural capital"…

  15. Higher order harmonic detection for exploring nonlinear interactions with nanoscale resolution

    PubMed Central

    Vasudevan, R. K.; Okatan, M. Baris; Rajapaksa, I.; Kim, Y.; Marincel, D.; Trolier-McKinstry, S.; Jesse, S.; Valanoor, N.; Kalinin, S. V.

    2013-01-01

    Nonlinear dynamics underpin a vast array of physical phenomena ranging from interfacial motion to jamming transitions. In many cases, insight into the nonlinear behavior can be gleaned through exploration of higher order harmonics. Here, a method using band excitation scanning probe microscopy (SPM) to investigate higher order harmonics of the electromechanical response, with nanometer scale spatial resolution is presented. The technique is demonstrated by probing the first three harmonics of strain for a Pb(Zr1-xTix)O3 (PZT) ferroelectric capacitor. It is shown that the second order harmonic response is correlated with the first harmonic response, whereas the third harmonic is not. Additionally, measurements of the second harmonic reveal significant deviations from Rayleigh-type models in the form of a much more complicated field dependence than is observed in the spatially averaged data. These results illustrate the versatility of nth order harmonic SPM detection methods in exploring nonlinear phenomena in nanoscale materials. PMID:24045269

  16. Effectiveness of Physical Activity Interventions for Preschoolers: A Meta-Analysis

    ERIC Educational Resources Information Center

    Gordon, Elliott S.; Tucker, Patricia; Burke, Shauna M.; Carron, Albert V.

    2013-01-01

    Purpose: The purpose of the meta-analysis was to examine the effectiveness of physical activity interventions on physical activity participation among preschoolers. A secondary purpose was to investigate the influence of several possible moderator variables (e.g., intervention length, location, leadership, type) on moderate-to-vigorous physical…

  17. Covariate selection with iterative principal component analysis for predicting physical soil properties

    E-print Network

    Covariate selection with iterative principal component analysis for predicting physical soil was to advance data-driven digital soil mapping techniques for the prediction of soil physical properties at high, and geostatistical techniques for effective spatial prediction of soil physical properties in a semiarid ecosystem

  18. Analysis of Navy Physical Evaluation Board diagnoses (1998-2000).

    PubMed

    Bohnker, Bruce K; Telfair, Tamara; McGinnis, James A; Malakooti, Mark A; Sack, David M

    2003-06-01

    An analysis is provided from 19,265 Physical Evaluation Board diagnoses from 10,406 Navy personnel from 1998 to 2000. The leading diagnostic categories were musculoskeletal and mental disorders as well as for subgroups of women and officers. Musculoskeletal conditions were 41.6% of the diagnoses and decreased with advancing age (42.9% for <30 years; 41.1% for 30-40 years; 37.6% for >40 years; chi2 for trend [1 df] = 26.4; p = 0.000). Mental disorders were 11.8% of the diagnoses and also decreased with advancing age (14.1% for <30 years; 10.4% for 30-40 years; 8.8% for >40 years; chi2 for trend [1 df] = 84; p = 0.000). Diagnoses for injury and poisoning (8.9%), nervous system (7.6%), and ill-defined conditions (4.7%) completed the top five categories below age 40 years, whereas circulatory disorders were evident after age 40 years. These findings suggest priorities for reducing overall medical disability losses in our active duty Navy forces. PMID:12834141

  19. Structural, Physical, and Compositional Analysis of Lunar Simulants and Regolith

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul; Street, Kenneth W.; Gaier, James

    2008-01-01

    Relative to the prior manned Apollo and unmanned robotic missions, planned Lunar initiatives are comparatively complex and longer in duration. Individual crew rotations are envisioned to span several months, and various surface systems must function in the Lunar environment for periods of years. As a consequence, an increased understanding of the surface environment is required to engineer and test the associated materials, components, and systems necessary to sustain human habitation and surface operations. The effort described here concerns the analysis of existing simulant materials, with application to Lunar return samples. The interplay between these analyses fulfills the objective of ascertaining the critical properties of regolith itself, and the parallel objective of developing suitable stimulant materials for a variety of engineering applications. Presented here are measurements of the basic physical attributes, i.e. particle size distributions and general shape factors. Also discussed are structural and chemical properties, as determined through a variety of techniques, such as optical microscopy, SEM and TEM microscopy, Mossbauer Spectroscopy, X-ray diffraction, Raman microspectroscopy, inductively coupled argon plasma emission spectroscopy and energy dispersive X-ray fluorescence mapping. A comparative description of currently available stimulant materials is discussed, with implications for more detailed analyses, as well as the requirements for continued refinement of methods for simulant production.

  20. PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.

    SciTech Connect

    Cheng, L.; Diamond, D.; Xu, J.; Carew, J.; Rorer, D.

    2004-03-31

    Detailed reactor physics and safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron and photon transport calculations were performed with the MCNP code to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim safety arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim safety arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model that includes the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the core power transient is terminated by a reactor trip at 26 MW. The calculations show that both the peak reactor power and the excursion energy depend on the negative reactivity insertion from reactor trip. In one of the loss-of-flow accidents offsite electrical power is assumed lost to the three operating primary pumps. A slightly delayed reactor scram is initiated as a result of primary flow coast down. The RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur, because of the momentum of the coolant flowing through the fuel channels and the negative scram reactivity insertion. For both the primary pump seizure and inadvertent throttling of a flow control valve, the RELAP5 analyses indicate that the reduction in power following the trip is sufficient to ensure that there is adequate margin to CHF and that the fuel cladding does not fail. The analysis of the loss-of-flow accident in the extremely unlikely case where both shutdown pumps fail, shows that the cooling provided by the D{sub 2}O is sufficient to ensure the cladding does not fail. The power distributions were examined for a set of fuel misloadings in which a fresh fuel element is moved from a peripheral low-reactivity location to a central high-reactivity location. The calculations show that there is adequate margin to CHF and the cladding does not fail. An additional analysis was performed to simulate the operation at low power (500 kW) without forced flow cooling. The result indicates that natural convection cooling is adequate for operation of the NBSR at a power level of 500 kW.

  1. Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-ray Free Electron Lasers

    SciTech Connect

    Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodle, M.; /SLAC; ,

    2012-02-15

    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science.

  2. Thermodynamics of the harmonic oscillator: Wien's displacement law and the Planck spectrum

    Microsoft Academic Search

    Timothy H. Boyer

    2003-01-01

    A thermodynamic analysis of the harmonic oscillator is presented. The motivation is provided by the blackbody radiation spectrum, because radiation modes take the harmonic-oscillator form. We use the behavior of a thermal harmonic oscillator system under a quasistatic change of oscillator frequency omega to show that the thermodynamic functions can all be derived from a single function of omega\\/T, analogous

  3. NONLINEAR OPTICAL EFFECTS AND INSTRUMENTS: Phase effects in multistage fourth-harmonic generation

    Microsoft Academic Search

    Z. A. Tagiev; Sh Sh Amirov

    1992-01-01

    An analysis is made of the process of multistage fourth-harmonic generation. Use is made of the approximation of a constant intensity and an allowance is made for the reaction of the fourth harmonic on the phase of the fundamental (first-harmonic) radiation. It is shown that selection of the optimal lengths of crystals can ensure a considerable increase in the efficiency

  4. On the second harmonic control requirements in balanced common-emitter BJT low noise amplifier

    Microsoft Academic Search

    Antti Heiskanen; Timo Rahkonen

    2004-01-01

    A recently proposed second harmonic controlled frequency-independent third-order intermodulation distortion cancellation technique in a balanced common-emitter configuration gives possibility to optimize linearity independently of noise power. By using simplified Volterra analysis new rules for second harmonic controlled cancellation are given. The results are confirmed by harmonic balance stimulations.

  5. Parallelization of the Physical-Space Statistical Analysis System (PSAS)

    NASA Technical Reports Server (NTRS)

    Larson, J. W.; Guo, J.; Lyster, P. M.

    1999-01-01

    Atmospheric data assimilation is a method of combining observations with model forecasts to produce a more accurate description of the atmosphere than the observations or forecast alone can provide. Data assimilation plays an increasingly important role in the study of climate and atmospheric chemistry. The NASA Data Assimilation Office (DAO) has developed the Goddard Earth Observing System Data Assimilation System (GEOS DAS) to create assimilated datasets. The core computational components of the GEOS DAS include the GEOS General Circulation Model (GCM) and the Physical-space Statistical Analysis System (PSAS). The need for timely validation of scientific enhancements to the data assimilation system poses computational demands that are best met by distributed parallel software. PSAS is implemented in Fortran 90 using object-based design principles. The analysis portions of the code solve two equations. The first of these is the "innovation" equation, which is solved on the unstructured observation grid using a preconditioned conjugate gradient (CG) method. The "analysis" equation is a transformation from the observation grid back to a structured grid, and is solved by a direct matrix-vector multiplication. Use of a factored-operator formulation reduces the computational complexity of both the CG solver and the matrix-vector multiplication, rendering the matrix-vector multiplications as a successive product of operators on a vector. Sparsity is introduced to these operators by partitioning the observations using an icosahedral decomposition scheme. PSAS builds a large (approx. 128MB) run-time database of parameters used in the calculation of these operators. Implementing a message passing parallel computing paradigm into an existing yet developing computational system as complex as PSAS is nontrivial. One of the technical challenges is balancing the requirements for computational reproducibility with the need for high performance. The problem of computational reproducibility is well known in the parallel computing community. It is a requirement that the parallel code perform calculations in a fashion that will yield identical results on different configurations of processing elements on the same platform. In some cases this problem can be solved by sacrificing performance. Meeting this requirement and still achieving high performance is very difficult. Topics to be discussed include: current PSAS design and parallelization strategy; reproducibility issues; load balance vs. database memory demands, possible solutions to these problems.

  6. Polynomial Harmonic Morphisms Martin Svensson

    E-print Network

    Gudmundsson, Sigmundur

    Polynomial Harmonic Morphisms Martin Svensson Examensarbete, 20 poang Lunds Universitet November- agement. Martin Svensson 3 #12;4 #12;CHAPTER 1 Introduction 1. Motivation The study of harmonic morphisms

  7. Improving the Performance of High-Energy Physics Analysis through Bitmap Indices

    E-print Network

    Hoschek, Wolfgang

    Improving the Performance of High-Energy Physics Analysis through Bitmap Indices Kurt Stockinger1 the design and implementation of bitmap in- dices for High-Energy Physics (HEP) analysis, where the potential-tree [6] or the BV-tree [4] and its variants to non-spatial data access methods like the Pyramid- tree [1

  8. BAYESIAN TIME SERIES: Models and Computations for the Analysis of Time Series in the Physical Sciences

    E-print Network

    West, Mike

    BAYESIAN TIME SERIES: Models and Computations for the Analysis of Time Series in the Physical Abstract. This articles discusses developments in Bayesian time series mod­ elling and analysis relevant in studies of time series in the physical and engineer­ ing sciences. With illustrations and references, we

  9. Degradation in finite-harmonic subcarrier demodulation

    NASA Technical Reports Server (NTRS)

    Feria, Y.; Townes, S.; Pham, T.

    1995-01-01

    Previous estimates on the degradations due to a subcarrier loop assume a square-wave subcarrier. This article provides a closed-form expression for the degradations due to the subcarrier loop when a finite number of harmonics are used to demodulate the subcarrier, as in the case of the buffered telemetry demodulator. We compared the degradations using a square wave and using finite harmonics in the subcarrier demodulation and found that, for a low loop signal-to-noise ratio, using finite harmonics leads to a lower degradation. The analysis is under the assumption that the phase noise in the subcarrier (SC) loop has a Tikhonov distribution. This assumption is valid for first-order loops.

  10. Quantum Mechanical Search and Harmonic Perturbation

    E-print Network

    Jiang, J H R; Wu, C E; Chiou, Dah-Wei; Jiang, Jie-Hong R.; Wu, Cheng-En

    2007-01-01

    Perturbation theory in quantum mechanics studies how quantum systems interact with their environmental perturbations. Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Some important technology advances, such as masers, lasers, nuclear magnetic resonance, etc., originated from it. Here we add quantum computation to this list with a theoretical demonstration. Based on harmonic perturbation, a quantum mechanical algorithm is devised to search the ground state of a given Hamiltonian. The intrinsic complexity of the algorithm is continuous and parametric in both time T and energy E. More precisely, the probability of locating a search target of a Hamiltonian in N-dimensional vector space is shown to be 1/(1+ c N E^{-2} T^{-2}) for some constant c. This result is optimal. As harmonic perturbation provides a different computation mechanism, the algorithm may suggest new directions in realizing quantum computers.

  11. Quantum Mechanical Search and Harmonic Perturbation

    E-print Network

    Jie-Hong R. Jiang; Dah-Wei Chiou; Cheng-En Wu

    2007-09-14

    Perturbation theory in quantum mechanics studies how quantum systems interact with their environmental perturbations. Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Some important technology advances, such as masers, lasers, nuclear magnetic resonance, etc., originated from it. Here we add quantum computation to this list with a theoretical demonstration. Based on harmonic perturbation, a quantum mechanical algorithm is devised to search the ground state of a given Hamiltonian. The intrinsic complexity of the algorithm is continuous and parametric in both time T and energy E. More precisely, the probability of locating a search target of a Hamiltonian in N-dimensional vector space is shown to be 1/(1+ c N E^{-2} T^{-2}) for some constant c. This result is optimal. As harmonic perturbation provides a different computation mechanism, the algorithm may suggest new directions in realizing quantum computers.

  12. PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.

    SciTech Connect

    Carew, J.; Hanson, A.; Xu, J.; Rorer, D.; Diamond, D.

    2003-08-26

    Detailed reactor physics and safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional MCNP Monte Carlo neutron and photon transport calculations were performed to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model including the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the core power transient is terminated by a reactor trip at 30 MW. The calculations show that both the peak reactor power and the excursion energy depend on the negative reactivity insertion from reactor trip. Two cases were considered for loss of electrical power. In the first case offsite power is lost, resulting in an immediate scram caused by loss of power to the control rod system. In the second case power is lost to only the three operating primary pumps, resulting in a slightly delayed scram when loss-of-flow is detected as the pumps coast down. In both instances, RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur, because of the momentum of the coolant flowing through the fuel channels and the negative scram reactivity insertion. For both the primary pump seizure and inadvertent throttling of a flow control valve, the RELAP5 analyses indicate that the reduction in power following the trip is sufficient to ensure that there is adequate margin to CHF and the fuel cladding does not fail. The analysis of the loss-of-flow accident in the extremely unlikely case where both shutdown pumps fail shows that the cooling provided by the D{sub 2}O is sufficient to ensure the cladding does not fail. The power distributions were examined for a set of fuel misloadings in which a fresh fuel element is moved from a peripheral low-reactivity location to a central high-reactivity location. The calculations show that there is adequate margin to CHF and the cladding does not fail.

  13. J. Phys. I Yonce 7 (1997) 1039-1051 SEPTEMBER1997, PAGE 1039 A Padb Type Analysis of the Harmonic Generation Mechanism

    E-print Network

    Paris-Sud XI, Université de

    1997-01-01

    Generation Mechanism in Free Electron Lasers G. Dattoli (*), L. Giannessi, P-L- Ottaviani (**) and A. Segreto Free-electron lasers Abstract. The dynamics of the harmonic generation induced by the Free Electron applied to the description of the saturation dynamics of a Free Electron Laser (FEL) [1]. The main results

  14. Thermodynamics of the harmonic oscillator: Wien’s displacement law and the Planck spectrum

    Microsoft Academic Search

    Timothy H. Boyer

    2003-01-01

    A thermodynamic analysis of the harmonic oscillator is presented. Motivation\\u000afor the study is provided by the blackbody radiation spectrum; when blackbody\\u000aradiation is regarded as a system of noninteracting harmonic oscillator modes,\\u000athe thermodynamics follows from that of the harmonic oscillators. Using the\\u000abehavior of a harmonic oscillator thermodynamic system under a quasi-static\\u000achange of oscillator frequency w, we

  15. Interference effects in two-color high-order harmonic generation

    SciTech Connect

    He, X.; Dahlstroem, J. M.; Rakowski, R.; Persson, A.; Mauritsson, J.; L'Huillier, A. [Department of Physics, Lund University, P. O. Box 118, SE-221 00 Lund (Sweden); Heyl, C. M. [Department of Physics, Lund University, P. O. Box 118, SE-221 00 Lund (Sweden); Department of Physics, University of Marburg, Marburg (Germany)

    2010-09-15

    We study high-order harmonic generation in argon driven by an intense 800 nm laser field and a small fraction of its second harmonic. The intensity and divergence of the emitted even and odd harmonics are strongly modulated as a function of the relative delay between the two fields. We provide a detailed analysis of the underlying interference effects. The interference changes drastically when approaching the cutoff region due to a switch of the dominant trajectory responsible for harmonic generation.

  16. Harmonic prime movers

    Microsoft Academic Search

    Ian Rice; Gordon Smith

    2005-01-01

    Western Kentucky University is undertaking the development of a thermoacoustically powered acoustic agglomerator as a means of pretreating exhaust from coal generators before entering standard industrial electrostatic precipitators. In order to fulfill the design requirement of maintaining a clean, isolated environment for the thermoacoustic components, it will be necessary to operate a thermoacoustic prime mover in a harmonic mode, which

  17. A Harmonic Motion Experiment

    ERIC Educational Resources Information Center

    Gluck, P.; Krakower, Zeev

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)

  18. Harmonically excited orbital variations

    SciTech Connect

    Morgan, T.

    1985-08-06

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

  19. Dirac-Harmonic Maps

    Microsoft Academic Search

    Qun Chen; Juergen Jost; Jiayu Li; Guofang Wang

    2004-01-01

    We introduce a functional that couples the nonlinear sigma model with a spinor field: $L=\\\\int_M[|d\\\\phi|^2+(\\\\psi,\\\\D\\\\psi)]$. In two dimensions, it is conformally invariant. The critical points of this functional are called Dirac-harmonic maps. We study some geometric and analytic aspects of such maps, in particular a removable singularity theorem.

  20. A harmonic motion experiment

    Microsoft Academic Search

    P. Gluck; Zeev Krakower

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions.