These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

High Harmonic Generation Physics 208A Presentation  

E-print Network

High Harmonic Generation Physics 208A Presentation October 11, 2004 Tom Allison UC Berkeley #12 to Fourier components of the polarization at harmonics of the laser frequency, creating radiation at harmonics of the laser frequency. #12;· First demonstration of second harmonic generation by P.A. Franken et

Budker, Dmitry

2

The harmonic oscillator and nuclear physics  

NASA Technical Reports Server (NTRS)

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.

Rowe, D. J.

1993-01-01

3

Data Compression and Harmonic Analysis  

Microsoft Academic Search

In this paper we review some recent interactions between harmonic analysis and data compression. The story goes back of course to Shannon's theory in the case of Gaussian stationary processes, which says that transforming into a Fourier basis followed by block coding gives an optimal lossy compression technique; practical developments like transform- based image compression have been inspired by this

David L. Donoho; Martin Vetterli; Ronald A. Devore; Ingrid Daubechies

1998-01-01

4

Harmonic Contribution Evaluation using Independent Component Analysis  

NASA Astrophysics Data System (ADS)

The widespread use of power electronic devices caused the harmonic pollution in power systems. However, it is difficult to determine customer and utility responsibility for harmonic distortion at the point of common coupling (PCC). In this letter, we propose a method to evaluate harmonic contribution at the PCC using independent component analysis (ICA). This method can evaluate the true harmonic contribution of utility and customer without estimating the harmonic impedance.

Lian, Suo; Ito, Daisuke; Takayama, Satoshi; Ishigame, Atsushi; Kitagawa, Masahiro; Katayama, Kousaku; Nakatani, Hideyuki; Takeuchi, Masayasu

5

Harmonic Analysis of the Output Voltage of a Third-Harmonic-Injected Inverter for LSM Drives  

NASA Astrophysics Data System (ADS)

The superconducting magnetic levitation railway system (MAGLEV) under development in Japan uses a pulse-width-modulation (PWM) inverter for driving a linear synchronous motor (LSM). The inverter output voltage contains non-negligible harmonics which cause harmonic resonances in the LSM system, and therefore harmonics of the output voltage have been analyzed in order to control such harmonic resonances. This paper applies a third-harmonic injection method to the inverter for the purpose of enhancing the output voltage without changing the circuit configuration. It performs harmonic analysis of the output voltage of the inverter based on the third-harmonic injection. Validity of the harmonic analysis is verified by computer simulation.

Shigeeda, Hidenori; Okui, Akinobu; Akagi, Hirofumi

6

Spherical harmonic analysis of wavefields using multiple circular sensor arrays  

E-print Network

Spherical harmonic analysis of wavefields using multiple circular sensor arrays Thushara D. Abhayapala, Senior Member, IEEE and Aastha Gupta Student Member, IEEE Abstract Spherical harmonic of sensors to decompose a wavefield into spherical harmonic components. The new structure presented here

Abhayapala, Thushara D.

7

Reconstruction of local neutron physical functionals in surface harmonics method  

NASA Astrophysics Data System (ADS)

Formulas for reconstruction of local neutron physical functionals for a three-stage calculation of a 2D VVER-1000 core using the surface harmonics method are obtained, implemented in the SUHAM code, and verified.

Boyarinov, V. F.; Nevinitsa, V. A.

2010-12-01

8

Abstract Harmonic Analysis on Spacetime  

E-print Network

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

Kahar El-Hussein

2014-04-06

9

Lunar gravity - A harmonic analysis  

NASA Technical Reports Server (NTRS)

A sixteenth-degree and sixteenth-order spherical harmonic lunar gravity field has been derived from the long-term Keplerian variations in the orbits of the Apollo subsatellites and Lunar Orbiter 5. This model resolves the major mascon gravity anomalies of the lunar near side and is in very good agreement with line-of-sight acceleration results. The far-side map shows the major ringed basins to be strong localized negative anomalies located in broad regions of positive gravity which correspond closely to the highlands. The rms pressure levels calculated from equivalent-surface height variations show that the moon and earth support nearly equal pressures, whereas Mars is appreciably stronger. The moon appears to support larger loads than earth owing to its weaker central gravity field and perhaps a colder upper lithosphere. Significant differences between the low-degree gravity and topography spectra indicate that the longer-wavelength topographic features are isostatically compensated.

Ferrari, A. J.

1977-01-01

10

The physics of harmonic injection in a TWT  

Microsoft Academic Search

By studying solutions to the S-MUSE model an approximate 1-D nonlinear multifrequency TWT model, we have identified physical mechanisms for cases of harmonic injection. We highlight the structure of the solutions to S-MUSE, and comment on the mechanism whereby intermodulation products are generated. Then we use the structure of the solutions to identify the mechanism for harmonic injection in a

J. G. Wohlbier; J. H. Booske; I. Dobson

2002-01-01

11

Harmonic Analysis and Geometries of Digital Data Bases  

E-print Network

Harmonic Analysis and Geometries of Digital Data Bases AMS Session Special Sesson, 2010 () Harmonic Analysis of Data Bases January 14, 2010 1 / 41 #12;Local geometry described by a graph, Gavish) Harmonic Analysis of Data Bases January 14, 2010 2 / 41 #12;Local geometry described by a graph

Maggioni, Mauro

12

Harmonic Debye-Waller analysis of anharmonic vibrations  

NASA Astrophysics Data System (ADS)

We address the error resulting from application of the harmonic Debye-Waller factor to anharmonic vibrations. The mean-square atomic displacement determined from the harmonic analysis is compared to values obtained from an exact anharmonic analysis. In the case of strong anharmonicity, we find that the harmonic approximation introduces at most a ˜25% error. The temperature dependence determined from the harmonic analysis follows that found from the exact anharmonic analysis. Errors introduced by the harmonic approximation are comparable in magnitude to the usual systematic errors associated with diffraction experiments and Rietveld refinements.

Safarik, D. J.; Llobet, A.; Lashley, J. C.

2012-05-01

13

A harmonic analysis of lunar topography  

NASA Technical Reports Server (NTRS)

A global lunar topographic map has been derived from existing earth-based and orbital observations supplemented in areas without data by a linear autocovariance predictor. Of 2592 bins, each 5 deg square, 1380 (64.7% by area) contain at least one measurement. A spherical harmonic analysis to degree 12 yields a mean radius of 1737.53 plus or minus 0.03 km (formal standard error) and an offset of the center of figure of 1.98 plus or minus 0.06 km toward (19 plus or minus 2) deg S, (194 plus or minus 1) deg E. A Bouguer gravity map, derived from a 12-degree free-air gravity model and the present topography data, is presented for an elevation of 100 km above the mean surface. It is confirmed that the low-degree gravity harmonics are determined primarily by surface height variations and only secondarily by lateral density variations.

Bills, B. G.; Ferrari, A. J.

1977-01-01

14

Harmonic analysis of electrical distribution systems  

SciTech Connect

This report presents data pertaining to research on harmonics of electric power distribution systems. Harmonic data is presented on RMS and average measurements for determination of harmonics in buildings; fluorescent ballast; variable frequency drive; georator geosine harmonic data; uninterruptible power supply; delta-wye transformer; westinghouse suresine; liebert datawave; and active injection mode filter data.

NONE

1996-03-01

15

The Harmonic Domain: A frame of reference for power system harmonic analysis  

SciTech Connect

The Harmonic Domain is a general frame of reference for power system analysis in the steady state which models the coupling between phases and between harmonics. In this frame of reference the non-linear components, converted into harmonic Norton equivalents, are combined with the rest of the system and solved iteratively by the Newton-Raphson technique. This paper describes the structure of the new domain and illustrates its potential applications in a small power system with multiple non-linearities.

Arrillaga, J.; Medina, A.; Lisboa, M.L.V. [Univ. of Canterbury (New Zealand)] [Univ. of Canterbury (New Zealand); Cavia, M.A.; Sanchez, P. [Univ. of Cantabria (Spain)] [Univ. of Cantabria (Spain)

1995-02-01

16

Spherical harmonic transit analysis with PAPER  

NASA Astrophysics Data System (ADS)

We discuss the implementation of an all-sky spherical harmonic transit analysis in the context of observed data from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER). The technique (Shaw et al. 2014a,b), dubbed the m-mode formalism, circumvents the flat-sky approximation of traditional interferometric analysis and is presented as an option for more effective analysis for instruments investigating 21 cm cosmology. Using this framework, we apply PAPER data obtained from 32 dual-polarization antennas and show preliminary results for imaging. We explore these results and discuss further implications of this m-mode formalism towards data analysis of PAPER including other antenna array configurations and polarization sources.

Ling, Jason; Aryeh Kohn, Saul; Aguirre, James E.; Paper Collaboration

2015-01-01

17

HARMONIC COMPONENT DETECTION: OPTIMIZED SPECTRAL KURTOSIS FOR OPERATIONAL MODAL ANALYSIS  

E-print Network

1 HARMONIC COMPONENT DETECTION: OPTIMIZED SPECTRAL KURTOSIS FOR OPERATIONAL MODAL ANALYSIS J of Operational Modal Analysis to identify the modal parameters of mechanical structures using only measured Response Function MA : Modal Analysis OMA : Operational Modal Analysis OSK : Optimized Spectral Kurtosis

Boyer, Edmond

18

Modular Approach to Physics: Simple Harmonic Motion - Weighted Spring  

NSDL National Science Digital Library

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 explicit directions and lesson ideas for instructors. This item is part of a larger collection of physics simulations sponsored by the MAP project (Modular Approach to Physics).

2008-08-12

19

Enhancing tidal harmonic analysis: Robust (hybrid L1 ) solutions  

E-print Network

Enhancing tidal harmonic analysis: Robust (hybrid L1 =L2 ) solutions Keith E. Leffler Ã?, David A 24 February 2008 Accepted 28 April 2008 Keywords: Tides Tidal analysis Harmonic analysis Robust is calculated from the power spectrum of the residual, a calculation that filters broad spectrum noise

Jay, David

20

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

E-print Network

-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

Oak Ridge National Laboratory

21

Analysis of enhanced second-harmonic generation in periodic nanostructures  

E-print Network

Analysis of enhanced second-harmonic generation in periodic nanostructures using modified rigorous technique to analyze second-harmonic genera- tion (SHG) in periodic optical nanostructures in the undepleted-pump approximation. We apply this method to analyze SHG in two example nanostructures for which we predict enhanced

Fainman, Yeshaiahu

22

Operational modal analysis in the presence of harmonic excitation  

Microsoft Academic Search

Modal operational analysis methods are procedures to identify modal parameters of structures from the response to unknown random excitations existing on buildings and in machines during operation. In many practical cases, in addition to the random loads, harmonic excitations are also present due for instance to rotating components. If the frequency of the harmonic component of the input is close

P. Mohanty; D. J. Rixen

2004-01-01

23

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

NASA Technical Reports Server (NTRS)

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.

Gurgiolo, Chris; Vinas, Adolfo F.

2009-01-01

24

Application of Modal Sensitivity for Power System Harmonic Resonance Analysis  

SciTech Connect

Abstract—Harmonic resonance is closely related to the singularity of a network admittance matrix. The smallest eigenvalue of the matrix defines the mode of harmonic resonance. This paper applies this eigenvalue theory and proposes a method to determine which network components have significant contributions to a harmonic resonance phenomenon. The basic idea is to calculate the sensitivities of a resonance mode to the parameters of network components. The sensitivity results are then ranked to quantify the impact of each component. In this paper, the eigen-sensitivity theory as applied to harmonic resonance mode analysis is presented. Case studies are used to verify the theory. A practical example is given to illustrate the application of the proposed method. In addition, this paper further conducts extensive comparative analysis on three types of network oriented modal analysis techniques. The results have clarified the similarities and differences among the techniques.

Huang, Zhenyu; Cui, Yu; Xu, Wilsun

2007-02-15

25

An electromagnetic time-harmonic analysis of shielded microstrip circuits  

Microsoft Academic Search

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.

JAMES C. RAUTIO; Roger F. Harrington

1987-01-01

26

TOPICS IN HARMONIC ANALYSIS APPLICATIONS TO RADAR AND SONAR  

E-print Network

TOPICS IN HARMONIC ANALYSIS WITH APPLICATIONS TO RADAR AND SONAR Willard Miller October 23, 2002, both commutative and noncommutative, that are fundamental for the analysis of radar and sonar imaging for the noncommutative groups which arise in radar­sonar. The insight and results obtained will are related directly

Olver, Peter

27

TOPICS IN HARMONIC ANALYSIS APPLICATIONS TO RADAR AND SONAR  

E-print Network

TOPICS IN HARMONIC ANALYSIS WITH APPLICATIONS TO RADAR AND SONAR Willard Miller October 23, 2002 commutative and noncommutative, that are fundamental for the analysis of radar and sonar imaging. Several for the noncommutative groups which arise in radar-sonar. The insight and results obtained will are related directly

Weinberger, Hans

28

Harmonic analysis on a galois field and its subfields  

E-print Network

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.

A. Vourdas

2006-10-17

29

THE UNCERTAINTY PRINCIPLE IN HARMONIC ANALYSIS BLAINE TALBUT  

E-print Network

THE UNCERTAINTY PRINCIPLE IN HARMONIC ANALYSIS BLAINE TALBUT Abstract. We present several uncertainty principle results from Fourier anal- ysis. The results we present are formally unrelated to one transform simultaneously. Contents 1. Introduction 1 2. Heisenberg's Uncertainty Principle 2 3. Complex

May, J. Peter

30

Harmonic analysis of the Ha velocity field of NGC 4254  

E-print Network

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.

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

2005-12-20

31

High-Speed Video Analysis of Damped Harmonic Motion  

ERIC Educational Resources Information Center

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…

Poonyawatpornkul, J.; Wattanakasiwich, P.

2013-01-01

32

HHFW (High Harmonic Fast Wave) Eddy Current Analysis for Antenna  

E-print Network

1 NSTX HHFW (High Harmonic Fast Wave) Eddy Current Analysis for Antenna NSTX-CALC-24-03-01 June 1 performed.) The model was first built for NSTX to verify the eddy current effect on antenna during plasma force of the induced eddy current in the components. The force data was transferred to the structural

Princeton Plasma Physics Laboratory

33

Circular current loops, magnetic dipoles and spherical harmonic analysis.  

USGS Publications Warehouse

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

Alldredge, L.R.

1980-01-01

34

A harmonic analysis of lunar gravity  

NASA Technical Reports Server (NTRS)

An improved model of lunar global gravity has been obtained by fitting a sixteenth-degree harmonic series to a combination of Doppler tracking data from Apollo missions 8, 12, 15, and 16, and Lunar Orbiters 1, 2, 3, 4, and 5, and laser ranging data to the lunar surface. To compensate for the irregular selenographic distribution of these data, the solution algorithm has also incorporated a semi-empirical a priori covariance function. Maps of the free-air gravity disturbance and its formal error are presented, as are free-air anomaly and Bouguer anomaly maps. The lunar gravitational variance spectrum has the form V(G; n) = O(n to the -4th power), as do the corresponding terrestrial and martian spectra. The variance spectra of the Bouguer corrections (topography converted to equivalent gravity) for these bodies have the same basic form as the observed gravity; and, in fact, the spectral ratios are nearly constant throughout the observed spectral range for each body. Despite this spectral compatibility, the correlation between gravity and topography is generally quite poor on a global scale.

Bills, B. G.; Ferrari, A. J.

1980-01-01

35

Harmonic Analysis and Qualitative Uncertainty Principle  

E-print Network

This paper investigates the mathematical nature of qualitative uncertainty principle (QUP), which plays an important role in mathematics, physics and engineering fields. Consider a 3-tuple (K, H1, H2) that K: H1 -> H2 is an integral operator. Suppose a signal f in H1, {\\Omega}1 and {\\Omega}2 are domains on which f, Kf define respectively. Does this signal f vanish if |{\\Sigma}(f)|uncertainty principle, nonlinear method and sparse representation, are thus suggested. The notion of operator family is developed and is applied to understand remarkable performances of recent sparse representation.

Ji King

2010-08-09

36

On harmonic binomial series  

E-print Network

We evaluate binomial series with harmonic number coefficients, providing recursion relations, integral representations, and several examples. The results are of interest to analytic number theory, the analysis of algorithms, and calculations of theoretical physics, as well as other applications.

Mark W. Coffey

2008-12-09

37

Harmonic Analysis of Polynomial Threshold Functions  

Microsoft Academic Search

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

Jehoshua Bruck

1990-01-01

38

Probabilistic Harmonic Analysis of Wind Generators Based on Generalized Gamma Mixture Models  

NASA Astrophysics Data System (ADS)

Grid-connected wind generators pose the power quality problems such as harmonic propagation and summation, and these problems are hard to solve by deterministic harmonic analysis due to the random harmonic current emissions. In this paper, probabilistic harmonic analysis is utilized to approximate harmonic currents of wind generators. Generalized gamma mixture models based on Gaussian mixture models, phasor clustering and generalized gamma models, are proposed to approximate the probability density functions of harmonic propagation and summation. And the simulation network built on PSCAD/EMTDC is utilized to verify the proposed models and method.

Xie, Guanglong; Zhang, Buhan

2013-01-01

39

HFAST - A harmonic analysis program for Stirling cycles  

NASA Astrophysics Data System (ADS)

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.

Huang, S. C.

40

A fictitious domain method using equilibrated basis functions for harmonic and bi-harmonic problems in physics  

NASA Astrophysics Data System (ADS)

In this paper we present a new meshless method to solve well-known problems in physics and engineering with either constant or variable material properties in 2D space. Harmonic and bi-harmonic problems are considered in this paper. The method constructs a set of basis functions, called Equilibrated Basis Functions (EqBFs), through a weighted residual integration over a fictitious domain embedding the main one. The bases can satisfy the governing partial differential equations approximately. Chebyshev polynomials of the first kind are employed to construct the EqBFs and exponential functions are used as the weights in the integrals. The parameters of the solution are arranged so that all the integrals can be decomposed into much simpler 1D ones over a normalized intervals. This reduces the computational efforts significantly. Either the EqBFs or the results of the integration process may be stored for further use. The validity of the results is examined through an extended patch test. A set of physical sample problems with variable/non-variable material properties; as the potential flow over a cylinder, steady-state heat conduction problems in an anisotropic inhomogeneous functionally graded material, potential and stokes flow through a channel of finite width obstructed by periodic cylinders, and the bending of thin elastic plates having constant or variable thickness are solved to demonstrate the capabilities of the method. As a preliminary study, we show that the method may effectively be used in a domain decomposition approach.

Noormohammadi, N.; Boroomand, B.

2014-09-01

41

Bayesian Analysis of Multiple Harmonic Oscillations in the Solar Corona  

E-print Network

The detection of multiple mode harmonic kink oscillations in coronal loops enables 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. Then, the two models are compared using a Bayesian model comparison scheme to assess how plausible each one is, given our current state of knowledge.

Arregui, I; Diaz, A J

2013-01-01

42

Bayesian Analysis of Multiple Harmonic Oscillations in the Solar Corona  

NASA Astrophysics Data System (ADS)

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.

Arregui, I.; Asensio Ramos, A.; Díaz, A. J.

2013-03-01

43

Multiscale image features analysis with circular harmonic wavelets  

NASA Astrophysics Data System (ADS)

In this contribution we introduce a new family of wavelets named Circular Harmonic Wavelets (CHW), suited for multiscale feature-based representations, that constitute a basis for general steerable wavelets. The family is based on Circular Harmonic Functions (CHF) derived by the Fourier expansion of local Radial Tomographic Projections. A multiscale general feature analysis can be performed by linearly combining the outputs of CHW operators of different order. After a survey on the general properties of the CHFs, we investigate the relationship between CHF and the wavelet expansion, stating the basic admissibility and stability conditions with reference to the Hankel transform of the radial profiles and describing some fundamental mathematical properties. Finally some applications are illustrated through examples.

Jacovitti, Giovanni; Neri, Alessandro

1995-09-01

44

BAYESIAN ANALYSIS OF MULTIPLE HARMONIC OSCILLATIONS IN THE SOLAR CORONA  

SciTech Connect

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.

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

45

Theoretical Analysis of High-Harmonic Generation in Solids  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

46

RF physics of ICWC discharge at high cyclotron harmonics  

SciTech Connect

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.

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

47

RF physics of ICWC discharge at high cyclotron harmonics  

NASA Astrophysics Data System (ADS)

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,?=?H+, and with its high cyclotron harmonics (HCH), ?=10?cH+? HCH scenario: very high antenna coupling to low density RF plasmas (Ppl?0.9PRF-G) and low energy Maxwellian distribution of CX hydrogen atoms with temperature TH?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?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 BT-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 Te plasmas is studied at fundamental ICR and its high harmonics.

Lyssoivan, A.; van Eester, D.; Wauters, T.; Bobkov, V.; Vervier, M.; Douai, D.; Kogut, D.; Kreter, A.; Moiseenko, V.; Möller, S.; Noterdaeme, J.-M.; Philipps, V.; Rohde, V.; Schneider, P.; Sergienko, G.; van Schoor, M.; Textor Team, ASDEX Upgrade Team

2014-02-01

48

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

E-print Network

STATISTICAL PARSING FOR HARMONIC ANALYSIS OF JAZZ CHORD SEQUENCES Mark Granroth-Wilding, Mark processing (NLP) to the problem of analysing harmonic progression. It uses a formal gram- mar of jazz chord space. Using supervised learning over a small corpus of jazz chord sequences annotated with harmonic

Steedman, Mark

49

Kinematic analysis of stellar radial velocities by the spherical harmonics  

NASA Astrophysics Data System (ADS)

A method for a kinematic analysis of stellar radial velocities using spherical harmonics is proposed. This approach does not depend on the specific kinematic model and allows both low-frequency and high-frequency kinematic radial velocity components to be analyzed. The possible systematic variations of distances with coordinates on the celestial sphere that, in turn, are modeled by a linear combination of spherical harmonics are taken into account. Theoretical relations showing how the coefficients of the decomposition of distances affect the coefficients of the decomposition of the radial velocities themselves have been derived. It is shown that the larger the mean distance to the sample of stars being analyzed, the greater the shift in the solar apex coordinates, while the shifts in the Oort parameter A are determined mainly by the ratio of the second zonal harmonic coefficient to the mean distance to the stars, i.e., by the degree of flattening of the spatial distribution of stars toward the Galactic plane. The distances to the stars for which radial velocity estimates are available in the CRVAD-2 catalog have been decomposed into spherical harmonics, and the existing variations of distances with coordinates are shown to exert no noticeable influence on both the solar motion components and the estimates of the Oort parameter A, because the stars from this catalog are comparatively close to the Sun (no farther than 500 pc). In addition, a kinematic component that has no explanation in terms of the three-dimensional Ogorodnikov-Milne model is shown to be detected in the stellar radial velocities, as in the case of stellar proper motions.

Vityazev, V. V.; Tsvetkov, A. S.; Trofimov, D. A.

2014-11-01

50

Linear harmonic analysis of free-piston Stirling engines  

SciTech Connect

The equations that govern the behavior of free-piston Stirling engines are nonlinear differential equations. Traditional solution methods have been time-stepping integrations that can be plagued by numerical instabilities and can use large amounts of computer time. Closed-form analytical solutions are possible if the working gas behaves isothermally or if the nonlinear terms in the governing equations are replaced with accurate approximations. An almost closed-form solution method, called the linear harmonic analysis (LHA), has been developed for free-piston Stirling engine applications by representing all of the periodic variables with harmonic functions. The solution method accounts for the important thermodynamic losses that are coupled together in free-piston engines, yet it is efficient enough for optimization studies. The LHA method was compared with a standard numerical integration method to verify its mathematical accuracy. The LHA and numerical predictions for a sample free-piston Stirling engine configuration differed by <5% for all important parameters. Sensitivity studies using the LHA method have also shown that the thermodynamic loss assumptions used in an analysis can have a significant impact on the predicted dynamic behavior of a free-piston Stirling engine.

Chen, N.C.J.; Griffin, F.P.

1986-06-01

51

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

SciTech Connect

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.

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

1986-09-01

52

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

NASA Astrophysics Data System (ADS)

A model for the fifth-harmonic generation of pulsed IR lasers involving an external ring cavity resonating at the second harmonic has been developed. Numerical analysis is performed to show the relative effects of the pulse delay, input polarization, and orientation of the nonlinear crystals on the fifth harmonic power. The results are validated by published experimental results. The model is used to analyze and obtain the optimal combination of nonlinear optical crystals for the fifth-harmonic generation. Our calculation shows that the combination of LiB3O5 (LBO), CsLiB6O10 (CLBO), and CLBO crystals for the second-harmonic, fourth-harmonic, and fifth-harmonic generation steps respectively gives an approximate conversion of 30% from the fundamental to the fifth harmonic power, resulting in 2 W at 213 nm for an input of 7 W at 1064 nm.

Chang, Lien-Bee; Wang, S. C.; Kung, A. H.

2003-07-01

53

Research of second harmonic generation images based on texture analysis  

NASA Astrophysics Data System (ADS)

Texture analysis plays a crucial role in identifying objects or regions of interest in an image. It has been applied to a variety of medical image processing, ranging from the detection of disease and the segmentation of specific anatomical structures, to differentiation between healthy and pathological tissues. Second harmonic generation (SHG) microscopy as a potential noninvasive tool for imaging biological tissues has been widely used in medicine, with reduced phototoxicity and photobleaching. In this paper, we clarified the principles of texture analysis including statistical, transform, structural and model-based methods and gave examples of its applications, reviewing studies of the technique. Moreover, we tried to apply texture analysis to the SHG images for the differentiation of human skin scar tissues. Texture analysis method based on local binary pattern (LBP) and wavelet transform was used to extract texture features of SHG images from collagen in normal and abnormal scars, and then the scar SHG images were classified into normal or abnormal ones. Compared with other texture analysis methods with respect to the receiver operating characteristic analysis, LBP combined with wavelet transform was demonstrated to achieve higher accuracy. It can provide a new way for clinical diagnosis of scar types. At last, future development of texture analysis in SHG images were discussed.

Liu, Yao; Li, Yan; Gong, Haiming; Zhu, Xiaoqin; Huang, Zufang; Chen, Guannan

2014-09-01

54

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

E-print Network

NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES Geometric partial differential equations and their analysis as well as numerical simulation have recently S ¨OREN BARTELS Abstract. This article studies the numerical approximation of harmonic maps into surfaces

Bartels, Soeren

55

Data Compression and Harmonic Analysis D.L. Donoho, M. Vetterli,  

E-print Network

between harmonic analysis and data compression. The story goes back of course to Shannon's R(D) theory. Recent harmonic analysis constructions, such as wavelet transforms and Gabor transforms, are essentially accessible to outsiders. Nevertheless, through a extensive generalization of what Shannon called

Donoho, David

56

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

E-print Network

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

Yazici, Birsen

57

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

E-print Network

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

Yazici, Birsen

58

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

NASA Astrophysics Data System (ADS)

The physics of 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. Preparations are underway to conduct low harmonic fast wave heating experiments to investigate the potential for bulk ion heating and shear flow drive. The available RF power in CDX-U has been increased to ( ~1/2 MW) and the operating frequency of the CDX RF transmitter will be lowered to operate in the range of 8-10 MHz. This provides 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 overview of the CDX-U RF system modifications will be presented, as well as preliminary numerical studies of damping and mode conversion from METS and several hot plasma dispersion relation codes.

Spaleta, J.; Majeski, R.; Phillips, C. K.

2001-10-01

59

Harmonic analysis of spacecraft power systems using a personal computer  

NASA Technical Reports Server (NTRS)

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.

Williamson, Frank; Sheble, Gerald B.

1989-01-01

60

Harmonic analysis of music using combinatory categorial grammar   

E-print Network

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 ...

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

2013-11-28

61

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

E-print Network

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

Chu, Shih-I

62

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

Microsoft Academic Search

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

Vera Schlindwein; Joachim Wassermann; Frank Scherbaum

1995-01-01

63

Optical coherence tomography imaging based on non-harmonic analysis  

NASA Astrophysics Data System (ADS)

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.

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

2009-11-01

64

Spherical harmonic analysis for verfication of a global atmospheric model  

NASA Technical Reports Server (NTRS)

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.

Christidis, Z.; Spar, J.

1979-01-01

65

Analytic scaling analysis of high harmonic generation conversion efficiency  

E-print Network

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 ...

Falcao-Filho, Edilson L.

66

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

E-print Network

Numerical Analysis of Fifth-Harmonic Conversion of Low-Power Pulsed Nd:YAG Laser with Resonance pulse width caused by the resonance condition, the peak power density as well as the energy density March 13, 2003) A model for the fifth-harmonic generation of pulsed IR lasers involving an external ring

Kung, Andy

67

Harmonic analysis of iterated function systems with overlap  

NASA Astrophysics Data System (ADS)

An iterated function system (IFS) is a system of contractive mappings ?i:Y?Y, i =1,…,N (finite), where Y is a complete metric space. Every such IFS has a unique (up to scale) equilibrium measure (also called the Hutchinson measure ?), and we study the Hilbert space L2(? ). In this paper we extend previous work on IFSs without overlap. Our method involves systems of operators generalizing the more familiar Cuntz relations from operator algebra theory and from subband filter operators in signal processing. These Cuntz-like operator systems were used in recent papers on wavelet analysis by Baggett, Jorgensen, Merrill, and Packer [Contemp. Math. 345, 11-25 (2004)], where they serve as a first step to generating wavelet bases of Parseval type (alias normalized tight frames), i.e., wavelet bases with redundancy. Similarly, it was shown in work by Dutkay and Jorgensen [Rev. Mat. Iberoam. 22, 131-180 (2006)] that the iterative operator approach works well for generating wavelets on fractals from IFSs without overlap. But so far the more general and more difficult case of essential overlap has resisted previous attempts at a harmonic analysis and explicit basis constructions, in particular. The operators generating the appropriate Cuntz relations are composition operators, e.g., Fi:f?f??i, where (?i) is the given IFS. If the particular IFS is essentially nonoverlapping, it is relatively easy to compute the adjoint operators Si=Fi*, and the Si operators will be isometries in L2(?) with orthogonal ranges. For the case of essential overlap, we can use the extra terms entering in the computation of the operators Fi* as a "measure" of the essential overlap for the particular IFS we study. Here the adjoint operators Fi* refer to the Hilbert space L2(?), where ? is the equilibrium measure ? for the given IFS (?i).

Jorgensen, Palle E. T.; Kornelson, Keri; Shuman, Karen

2007-08-01

68

Calculation and analysis of the harmonic vibrational frequencies in molecules at extreme pressure: Methodology and diborane as a test case  

NASA Astrophysics Data System (ADS)

We present a new quantum chemical method for the calculation of the equilibrium geometry and the harmonic vibrational frequencies of molecular systems in dense medium at high pressures (of the order of GPa). The new computational method, named PCM-XP, is based on the polarizable continuum model (PCM), amply used for the study of the solvent effects at standard condition of pressure, and it is accompanied by a new method of analysis for the interpretation of the mechanisms underpinning the effects of pressure on the molecular geometries and the harmonic vibrational frequencies. The PCM-XP has been applied at the density functional theory level to diborane as a molecular system under high pressure. The computed harmonic vibrational frequencies as a function of the pressure have shown a satisfactory agreement with the corresponding experimental results, and the parallel application of the method of analysis has reveled that the effects of the pressure on the equilibrium geometry can be interpreted in terms of direct effects on the electronic charge distribution of the molecular solutes, and that the effects on the harmonic vibrational frequencies can be described in terms of two physically distinct effects of the pressure (curvature and relaxation) on the potential energy for the motion of the nuclei.

Cammi, R.; Cappelli, C.; Mennucci, B.; Tomasi, J.

2012-10-01

69

Calculation and analysis of the harmonic vibrational frequencies in molecules at extreme pressure: methodology and diborane as a test case.  

PubMed

We present a new quantum chemical method for the calculation of the equilibrium geometry and the harmonic vibrational frequencies of molecular systems in dense medium at high pressures (of the order of GPa). The new computational method, named PCM-XP, is based on the polarizable continuum model (PCM), amply used for the study of the solvent effects at standard condition of pressure, and it is accompanied by a new method of analysis for the interpretation of the mechanisms underpinning the effects of pressure on the molecular geometries and the harmonic vibrational frequencies. The PCM-XP has been applied at the density functional theory level to diborane as a molecular system under high pressure. The computed harmonic vibrational frequencies as a function of the pressure have shown a satisfactory agreement with the corresponding experimental results, and the parallel application of the method of analysis has reveled that the effects of the pressure on the equilibrium geometry can be interpreted in terms of direct effects on the electronic charge distribution of the molecular solutes, and that the effects on the harmonic vibrational frequencies can be described in terms of two physically distinct effects of the pressure (curvature and relaxation) on the potential energy for the motion of the nuclei. PMID:23083153

Cammi, R; Cappelli, C; Mennucci, B; Tomasi, J

2012-10-21

70

Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals  

E-print Network

Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals Hong analyses of tunable diode laser absorption spectroscopy signals were performed. The absorption spectroscopy because of their low cost. Tunable diode laser spectroscopy is often per- formed by measurement

Cheng, Harry H.

71

Analysis of the superconducting wiggler magnets for the ATF Harmonic Generation FEL experiment  

SciTech Connect

In this paper, we consider the superconducting wiggler magnet under construction for the High Gain Harmonic Generation experiment (HGHG) at the Accelerator Test Facility (ATF) at BNL. This wiggler consists of an energy modulation section, a dispersion magnet and a radiator section. We present an analysis of the dispersion magnet and the end effects in the other wiggler sections. The purpose of the dispersion magnet is to convert energy modulation of the electron beam into spatial bunching. For the dispersion magnet, we discuss the physical requirements, analyze the magnetic design, determine the focusing properties, and consider the effect of departures from ideal behavior on the FEL gain. In the modulator and radiator wigglers we analyze the effects due to the ends of the wiggler and discuss their correction. In addition, the localized field produced by a trim coil for horizontal beam steering is investigated.

Zhang, X.; Ben-Zvi, I.; Ingold, G.; Krinsky, S.; Yu, L.H.

1992-01-01

72

Analysis of the superconducting wiggler magnets for the ATF Harmonic Generation FEL experiment  

SciTech Connect

In this paper, we consider the superconducting wiggler magnet under construction for the High Gain Harmonic Generation experiment (HGHG) at the Accelerator Test Facility (ATF) at BNL. This wiggler consists of an energy modulation section, a dispersion magnet and a radiator section. We present an analysis of the dispersion magnet and the end effects in the other wiggler sections. The purpose of the dispersion magnet is to convert energy modulation of the electron beam into spatial bunching. For the dispersion magnet, we discuss the physical requirements, analyze the magnetic design, determine the focusing properties, and consider the effect of departures from ideal behavior on the FEL gain. In the modulator and radiator wigglers we analyze the effects due to the ends of the wiggler and discuss their correction. In addition, the localized field produced by a trim coil for horizontal beam steering is investigated.

Zhang, X.; Ben-Zvi, I.; Ingold, G.; Krinsky, S.; Yu, L.H.

1992-10-01

73

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

74

General harmonic balance solution of a cracked rotor-bearing-disk system for harmonic and sub-harmonic analysis: Analytical and  

E-print Network

General harmonic balance solution of a cracked rotor-bearing-disk system for harmonic and sub Structural health monitoring Breathing crack model Cracked rotor Harmonic balance method a b s t r a c t The effect of crack depth of a rotor-bearing-disk system on vibration amplitudes and whirl orbit shapes

Butcher, Eric A.

75

Harmonizing Physics & Cosmology With Everything Else in the Universe(s)  

NASA Astrophysics Data System (ADS)

This paper postulates a theory of everything including our known finite physical universe within and as sub-set of an infinite virtual invisible universe occupying some of the same space and time. It attempts to harmonize astrophysics with everything else including life. It compares and contrasts properties, similarities, differences and relationships between the two universe(s). A particular attention is paid to the interface between the two and the challenges of building and/or traversing bridges between them. A number of inflection points between the two are identified. The paper also delineates their relationship to big bang, theory of evolution, gravity, dark matter, black holes, time travel, speed of light, theory of relativity and string theory just to name a few. Several new terms are introduced and defined to discuss proper relationship, transition and interface between the body, soul and spirit as well as their relationship to brain and mind. Physical bodies & beings are compared with virtual, meta and ultra bodies and beings and how the ``Virtual Inside'' relates to people, pets, plants and particles and their micro constituents as well as macro sets. The past, present, and potential of the concurrent universe(s) is compared and contrasted along with many myths and misconceptions of the meta physics as well as modern physics.

Asija, Pal

2006-03-01

76

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

SciTech Connect

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.

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

77

Spherical harmonic decomposition applied to spatial-temporal analysis of human high-density EEG  

E-print Network

We demonstrate an application of spherical harmonic decomposition to analysis of the human electroencephalogram (EEG). We implement two methods and discuss issues specific to analysis of hemispherical, irregularly sampled data. Performance of the methods and spatial sampling requirements are quantified using simulated data. The analysis is applied to experimental EEG data, confirming earlier reports of an approximate frequency-wavenumber relationship in some bands.

Wingeier, B M; Silberstein, R B; Wingeier, Brett M.; Nunez, Paul L.; Silberstein, Richard B.

2001-01-01

78

PHYSICAL REVIEW A 86, 013411 (2012) Effects of macroscopic propagation on spectra of broadband supercontinuum harmonics  

E-print Network

supercontinuum harmonics and isolated-attosecond-pulse generation: Coherent control of the electron quantum it was shown that broadband supercontinuum harmonics can be produced from the long-trajectory electrons-color laser fields. Such supercontinuum harmonics can be superposed to generate an isolated sub-30- attosecond

Chu, Shih-I

79

Data harmonization and federated analysis of population-based studies: the BioSHaRE project  

PubMed Central

Abstracts Background Individual-level data pooling of large population-based studies across research centres in international research projects faces many hurdles. The BioSHaRE (Biobank Standardisation and Harmonisation for Research Excellence in the European Union) project aims to address these issues by building a collaborative group of investigators and developing tools for data harmonization, database integration and federated data analyses. Methods Eight population-based studies in six European countries were recruited to participate in the BioSHaRE project. Through workshops, teleconferences and electronic communications, participating investigators identified a set of 96 variables targeted for harmonization to answer research questions of interest. Using each study’s questionnaires, standard operating procedures, and data dictionaries, harmonization potential was assessed. Whenever harmonization was deemed possible, processing algorithms were developed and implemented in an open-source software infrastructure to transform study-specific data into the target (i.e. harmonized) format. Harmonized datasets located on server in each research centres across Europe were interconnected through a federated database system to perform statistical analysis. Results Retrospective harmonization led to the generation of common format variables for 73% of matches considered (96 targeted variables across 8 studies). Authenticated investigators can now perform complex statistical analyses of harmonized datasets stored on distributed servers without actually sharing individual-level data using the DataSHIELD method. Conclusion New Internet-based networking technologies and database management systems are providing the means to support collaborative, multi-center research in an efficient and secure manner. The results from this pilot project show that, given a strong collaborative relationship between participating studies, it is possible to seamlessly co-analyse internationally harmonized research databases while allowing each study to retain full control over individual-level data. We encourage additional collaborative research networks in epidemiology, public health, and the social sciences to make use of the open source tools presented herein. PMID:24257327

2013-01-01

80

SPHERICAL HARMONIC ANALYSIS OF EQUALIZATION IN A REVERBERANT ROOM Terence Betlehem and Thushara D. Abhayapala  

E-print Network

on performance. 2. MODAL DECOMPOSITION OF A SOUND FIELD Denote the frequency domain signal received at an omnidiSPHERICAL HARMONIC ANALYSIS OF EQUALIZATION IN A REVERBERANT ROOM Terence Betlehem and Thushara D-channel case proposed in [7] shows promise. However, as the robustness analysis in this case was based

Abhayapala, Thushara D.

81

Gravity and geoid model in South Korea and its vicinity by spherical cap harmonic analysis  

NASA Astrophysics Data System (ADS)

Long wavelength gravity anomalies derived from satellite data have limitations of spatial resolution and accuracy. To complement these weak points, combined datasets merged with shipborne/land gravity data and satellite data are generally compiled using global spherical harmonic, rectangular harmonic, or spherical cap harmonic analysis etc. However, each method also has a different resolution and accuracy. In this study, gravity anomalies and geoid undulations of South Korea and its vicinity are calculated using the spherical cap harmonic method, and the results are compared with those of GGM02C and EGM2008. Absolute and relative geoid height differences between GPS/leveling data and the results of various other methods show that the method used in this study has the lowest RMS error (0.271 m vs 0.344-0.416 m) and standard deviation (0.236 m vs 0.309-0.362 m). This implies that the spherical cap harmonic method has better resolution and accuracy than the other methods. The short wavelength gravity anomalies derived from the spherical cap harmonic coefficients are used to estimate the sediment thickness of the Ulleung Basin, which is poorly known. The sediment thickness of the Ulleung Basin is about 5 km at the center of the basin, and about 12 km at the southern margin.

Hwang, Jong Sun; Han, Hyun-Chul; Han, Shin-Chan; Kim, Kyong-O.; Kim, Jin-Ho; Kang, Moo-Hee; Kim, Chang Hwan

2012-01-01

82

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

E-print Network

Abstract--This paper presents the harmonic analysis of offshore wind farm (OWF) models with full will be discussed based on measurements from offshore wind farm. Index Terms--full-rating converters, harmonic analysis, offshore wind farm, wind turbine, validation with measurements I. INTRODUCTION HE tendency

Bak, Claus Leth

83

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

E-print Network

harmonic analysis and data compression. The story goes back of course to Shannon's R(D) theory in the case constructions, such as wavelet transforms and Gabor transforms, are essentially optimal transforms for transform- eralization of what Shannon called the "sampling theorem," harmonic analysis has succeeded in developing new

Vetterli, Martin

84

Full vector spherical harmonic analysis of the Holocene geomagnetic field  

NASA Astrophysics Data System (ADS)

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).

Richardson, Marcia

85

Newton-type algorithms for the harmonic phasor analysis of non-linear power circuits in periodical steady state with special reference to magnetic non-linearities  

SciTech Connect

Computer algorithms of the Newton-Raphson type are derived for the harmonic analysis of systems containing non-linear dynamic components in periodic steady state. The problem is formulated in the complex conjugate multi harmonic space which inherently represents the harmonic coupling between the different harmonic frequencies. The theory is applied to single phase systems including magnetic non-linearities.

Semlyen, A. (Univ. of Toronto, Toronto, Ontario (CA)); Acha, E.; Arrillaga, J. (Univ. of Canterbury, Christchurch (NZ))

1988-07-01

86

PROJET AURORA: COMPLEX AND HARMONIC ANALYSIS RELATED TO GENERATING SYSTEMS: PHASE SPACE LOCALIZATION PROPERTIES, SAMPLING  

E-print Network

PROJET AURORA: COMPLEX AND HARMONIC ANALYSIS RELATED TO GENERATING SYSTEMS: PHASE SPACE LOCALIZATION PROPERTIES, SAMPLING AND APPLICATIONS The aim of the AURORA project CHARGE is to join the efforts holds: A f 2 | f, |2 B f . 1 #12;2 AURORA PROJECT CHARGE The first property is of essential

Saut, Olivier

87

IEEE TRANSACTIONS ON AUDIO, SPEECH, AND LANGUAGE PROCESSING 1 Harmonic Adaptive Latent Component Analysis of  

E-print Network

Analysis of Audio and Application to Music Transcription Benoit Fuentes*, Graduate Student Member, IEEE the problem of automatic music transcription. However those tech- niques are not necessarily suitable narrowband harmonic spectra, spectrally convolved with some impulse that defines the pitch. All parameters

Badeau, Roland

88

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

NASA Technical Reports Server (NTRS)

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.

Rapp, Richard H.; Pavlis, Nikolaos K.

1990-01-01

89

Dynamic behavior analysis of cracked rotor based on harmonic motion  

NASA Astrophysics Data System (ADS)

In the present study the additional slope and bending moment at crack position are used in analyzing the dynamic behavior of a general cracked rotor. The nonlinear motion of the cracked rotor, which results in the harmonic vibration, is simulated using the response including bending moment and the additional slope recursively. Even though the change of the orbit at the subcritical speed occurs, the magnitude of additional slope does not change if the crack-induced dynamic bending moment is smaller than the gravity-induced static bending moment at the corresponding critical speed range; the cause of the orbit change is the high value of the displacement influence coefficient at the corresponding critical speed. Only at the speed range where the dynamic bending moment is enough large to affect the total bending moment, the change of additional slope occurs with the speed change and it becomes one of the causes of the drastic orbit change. In the present research model, the orbit change due to the large dynamic bending moment as well as the high influence coefficient occurs at around subcritical speeds of the second critical speed. The continuous operation of the cracked rotor at such speed range having large dynamic bending moment may produce the fast crack propagation. And also it is analyzed that the second vibration mode happens when the speed closely approaches half of the second critical speed.

Jun, Oh Sung

2012-07-01

90

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

NASA Astrophysics Data System (ADS)

In isogeometric analysis, parameterization of computational domain has great effects as mesh generation in finite element analysis. In this paper, based on the concept of harmonic mapping from the computational domain to parametric domain, a variational harmonic approach is proposed to construct analysis-suitable parameterization of computational domain from CAD boundary for 2D and 3D isogeometric applications. Different from the previous elliptic mesh generation method in finite element analysis, the proposed method focuses on isogeometric version, and converts the elliptic PDE into a nonlinear optimization problem, in which a regular term is integrated into the optimization formulation to achieve more uniform and orthogonal iso-parametric structure near convex (concave) parts of the boundary. Several examples are presented to show the efficiency of the proposed method in 2D and 3D isogeometric analysis.

Xu, Gang; Mourrain, Bernard; Duvigneau, Régis; Galligo, André

2013-11-01

91

Polarization Analysis of Nonlinear Harmonic Radiation in a Crossed-Planar Undulator  

SciTech Connect

There is growing interest in producing intense, coherent x-ray radiation with an adjustable and arbitrary polarization state. The crossed-planar undulator, which was first proposed by Kim, could achieve rapid polarization control in synchrotron radiation sources and free electron lasers (FELs) through the manipulation of a phase shifter. Recently, a statistical analysis shows that a polarization degree of over 80% is obtainable for a Self-Amplified Spontaneous Emission (SASE) FEL near saturation. In such a scheme, nonlinear harmonic radiation is also generated in each undulator and the polarization of the radiation is controllable in the same manner. In this paper, we study the degree of polarization achievable at the third harmonic in a crossed-planar undulator. We also propose a method for generating second harmonic radiation with arbitrary polarization.

Geng, H.; Ding, Y.; Huang, Z.; /SLAC

2009-06-23

92

Frequency domain interpolation wavelet transform based algorithm for harmonic analysis of power system  

Microsoft Academic Search

A power system harmonic detection technique based on a frequency domain interpolation wavelet transform is proposed. Aiming at harmonic detection, a fast Fourier transform (FFT) can only detect integer harmonics; a short time Fourier transform (STFT) can detect non-integer harmonics with low resolution; a wavelet transform can detect non-integer harmonics, but it has spectral aliasing and spectral leakage phenomena, which

Tianjun Du; Guangju Chen; Yong Lei

2004-01-01

93

Noise Reduction Process with Generalized Harmonics Analysis for High-Temperature Superconducting Quantum Interference Device Magnetocardiography  

NASA Astrophysics Data System (ADS)

Generalized harmonic analysis was applied to a high-temperature superconducting quantum interference device (SQUID) magnetocardiograph signal processing system. The noise frequencies in the signal waveform were calculated by the generalized harmonic analysis (GHA) and the noise components with these frequencies were subtracted from the acquired signal data. Two types of the subtraction procedure were demonstrated: one using the adaptive filtering algorithm and the other a simple subtraction. In both cases, the noise components were reduced. The former system performed rapid calculations but generated an artificial noise in the high-frequency region, because of rough GHA estimation, while in the latter case, the calculation was time-consuming but the noise estimation was carried out accurately, because of the precision of GHA procedure. In the present study, a distinctive noise component at 16 Hz was completely suppressed by the GHA prediction noise reduction process. The proposed systems were well suited for application to an unshielded high-temperature SQUID system.

Sakuta, Ken; Ogawa, Kaname; Tamai, Hideaki; Mizukami, Akifumi; Kobayashi, Takeshi

2002-10-01

94

High order harmonics from mid-infrared drivers for attosecond physics  

SciTech Connect

The generation of light pulses with attosecond (10{sup -18} seconds) duration is studied using laser drivers operating in the mid-infrared region. This paper first examines the fundamental principles of attosecond formation by Fourier synthesis of a high harmonic comb. Experimental demonstration of the extension of the harmonic cutoff is shown using a 2 micron driver. Then, the crucial spectral phase properties, responsible for the pulse structure on the attosecond time scale, are measured with an all-optical technique using a mix of the fundamental pulse with its second harmonic. The expected 1/lambda scaling is verified, which demonstrates a practical way towards pulses approaching the atomic unit of time (24 as).

Doumy, G.; Wheeler, J.; Roedig, C.; Agostini, P.; DiMauro, L. F. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States)

2009-09-10

95

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

NASA Technical Reports Server (NTRS)

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.

Fiske, David R.

2004-01-01

96

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

ERIC Educational Resources Information Center

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…

Triana, C. A.; Fajardo, F.

2012-01-01

97

Harmonic Band Spectrum Analysis of Backscattered Ultrasound from Lesioned and Normal Tissue  

NASA Astrophysics Data System (ADS)

HIFU dose curves (lesion size vs. exposure parameters) exhibit scatter because of local variations in the acoustic properties of tissue. Therefore, clinical applications of HIFU, such as cardiac and cancer ablation, will benefit from the ability to distinguish treated from normal tissue, which can provide the surgeon with lesion monitoring. However, HIFU lesions, especially protein-denaturing lesions (PDLs), may be difficult to visualize with conventional B-mode ultrasound. In this study, spectrum analysis of backscattered radiofrequency (RF) ultrasound was successful in imaging lesions. HIFU lesions were formed at 5 MHz for various intensities and durations in model tissues including degassed chicken breast in vitro, fresh rabbit liver ex vivo, and canine cardiac left ventricle in vivo. The tissues were scanned pre- and post-exposure using confocal array and single-element diagnostic probes incorporated into the HIFU transducer assembly. The diagnostic probes were excited with a monocycle pulse under conditions previously shown to generate a second harmonic comparable in amplitude to the fundamental, and RF echo-signal data were recorded. In an alternate set, the therapy and diagnostic transducers were operated pitch-catch, with the therapy transducer sending out a series of 0.4 ms pulses and the diagnostic transducer in passive receive mode. Spectrum analysis of the RF data was performed separately on first (fundamental) and second harmonic frequency bands. Linear regression fits to spectra computed for sliding regions-of-interest yielded 3 parameters: midband fit (integrated backscatter), y-intercept and slope; grayscale images were produced for each parameter. Differences among the B-mode and parameter images, and between the lesion site and adjacent untreated tissues, were characterized statistically. The results indicate that midband fit images of both the fundamental and harmonic offer improved contrast and lateral resolution compared to conventional images. PDLs and bubbly lesions that are not clearly visible in B-mode images can be imaged with harmonic band spectrum analysis.

Muratore, Robert; Lizzi, Frederic L.; Silverman, Ronald H.

2006-05-01

98

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

USGS Publications Warehouse

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.

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

1997-01-01

99

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

SciTech Connect

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.

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

100

Bioimpedance Harmonic Analysis as a Diagnostic Tool to Assess Regional Circulation and Neural Activity  

NASA Astrophysics Data System (ADS)

The novel technique based on harmonic analysis of bioimpedance microvariations with original hard- and software complex incorporating a high-resolution impedance converter was used to assess the neural activity and circulation in human urinary bladder and penis in patients with pelvic pain, erectile dysfunction, and overactive bladder. The therapeutic effects of shock wave therapy and Botulinum toxin detrusor injections were evaluated quantitatively according to the spectral peaks at low 0.1 Hz frequency (M for Mayer wave), respiratory (R) and cardiac (C) rhythms with their harmonics. Enhanced baseline regional neural activity identified according to M and R peaks was found to be presumably sympathetic in pelvic pain patients, and parasympathetic - in patients with overactive bladder. Total pulsatile activity and pulsatile resonances found in the bladder as well as in the penile spectrum characterised regional circulation and vascular tone. The abnormal spectral parameters characteristic of the patients with genitourinary diseases shifted to the norm in the cases of efficient therapy. Bioimpedance harmonic analysis seems to be a potent tool to assess regional peculiarities of circulatory and autonomic nervous activity in the course of patient treatment.

Mudraya, I. S.; Revenko, S. V.; Khodyreva, L. A.; Markosyan, T. G.; Dudareva, A. A.; Ibragimov, A. R.; Romich, V. V.; Kirpatovsky, V. I.

2013-04-01

101

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

SciTech Connect

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.

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

102

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

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

103

Harmonic and anharmonic aspects in the dynamics of BPTI: a normal mode analysis and principal component analysis.  

PubMed Central

A comparison is made between a 200-ps molecular dynamics simulation in vacuum and a normal mode analysis on the protein bovine pancreatic trypsin inhibitor (BPTI) in order to elucidate the dual aspects of harmonicity and anharmonicity in the dynamics of proteins. The molecular dynamics trajectory is analyzed using principal component analysis, an effective harmonic analysis suited for comparison with the results from the normal mode analysis. The results suggest that the first principal component shows qualitatively different behavior from higher principal components and is associated with apparent barrier crossing events on an anharmonic conformational energy surface. The higher principal components appear to have probability distributions that are well approximated by Gaussians, indicating harmonicity. Eliminating the contribution from the first principal component reveals a great deal of correspondence between the 2 methods. This correspondence, however, involves a factor of 2, as the variances of the distribution of the higher principal components are, on average, roughly twice those found from the normal mode analysis. A model is proposed to reconcile these results with those from previous analyses. PMID:7520795

Hayward, S.; Kitao, A.; Go, N.

1994-01-01

104

Boston University Physics: Connection between Circular and Simple Harmonic Motion Model  

NSDL National Science Digital Library

This computer model shows the the connection between uniform circular motion and simple harmonic motion by animating the movement of two spring/mass systems. Users can set amplitude, mass, and spring constant so the blocks have different angular frequencies. As the block/spring system moves, watch what happens to the corresponding circular motion animation. This connection is one way to justify the basic equation of motion for an object experiencing simple harmonic motion. This equation also corresponds to one dimension of uniform circular motion. In this simulation, the author goes beyond the equation to explore the phase angle. There are analogous equations for the velocity and the acceleration as a function of time. The Connection between Circular and Simple Harmonic Motion model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_reference_circle.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-03

105

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

NSDL National Science Digital Library

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.

Duffy, Andrew

106

Experimental analysis of the high-order harmonic components generation in few-layer graphene  

NASA Astrophysics Data System (ADS)

In this work, the nonlinear electromagnetic response of a few-layer graphene sheet is experimentally analyzed. The few-layer graphene sheet is obtained through mechanical exfoliation from highly ordered pyrolytic graphite and embedded in a rectangular waveguide structure which is used to guide the exciting and the output signals. The nonlinear electromagnetic response of the graphene sheet is exploited to implement a frequency multiplier in which the output signal, in the 330-500 GHz frequency band, will be obtained as a high-order harmonic component of the input signal, in the 26-40 GHz frequency band. Due to the particular selection of the input and output frequency ranges, the behavior of several harmonic components, from order 9 to 17, can be characterized. The analysis will be focused on the frequency response of the graphene sheet, the influence of the input power on the output signal and the differences between the even- and odd-order harmonic components. Finally, it will be shown that the developed assembly can be used as THz signal source based on high-order frequency multiplication.

Hadarig, Andreea I.; Vázquez, Carlos; Fernández, Miguel; Ver Hoeye, Samuel; Hotopan, George R.; Camblor, René; Las Heras, Fernando

2015-01-01

107

Experiment Design and Analysis Guide - Neutronics & Physics  

SciTech Connect

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.

Misti A Lillo

2014-06-01

108

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

NASA Astrophysics Data System (ADS)

Multiple-harmonic electromagnetic waves in the ULF band have occasionally been observed in Earth's magnetosphere, both near the magnetic equator in the outer plasmasphere and in the plasma sheet boundary layer (PSBL) in Earth's magnetotail. Observations by the Cluster spacecraft of multiple-harmonic electromagnetic waves with fundamental frequency near the local proton cyclotron frequency, ?cp, were recently reported in the plasma sheet boundary layer by Broughton et al. (2008). A companion paper surveys the entire magnetotail passage of Cluster during 2003, and reports 35 such events, all in the PSBL, and all associated with elevated fluxes of counterstreaming ions and electrons. In this study we use observed pitch angle distributions of ions and electrons during a wave event observed by Cluster on 9 September 2003 to perform an instability analysis. We use a semiautomatic procedure for developing model distributions composed of bi-Maxwellian components that minimizes the difference between modeled and observed distribution functions. Analysis of wave instability using the WHAMP electromagnetic plasma wave dispersion code and these model distributions reveals an instability near ?cp and its harmonics. The observed and model ion distributions exhibit both beam-like and ring-like features which might lead to instability. Further instability analysis with simple beam-like and ring-like model distribution functions indicates that the instability is due to the ring-like feature. Our analysis indicates that this instability persists over an enormous range in the effective ion beta (based on a best fit for the observed distribution function using a single Maxwellian distribution), ?', but that the character of the instability changes with ?'. For ?' of order unity (for instance, the observed case with ?' ˜ 0.4), the instability is predominantly electromagnetic; the fluctuating magnetic field has components in both the perpendicular and parallel directions, but the perpendicular fluctuations are larger. If ?' is greatly decreased to about 5 × 10-4 (by increasing the magnetic field), the instability becomes electrostatic. On the other hand, if ?' is increased (by decreasing the magnetic field), the instability remains electromagnetic, but becomes predominantly compressional (magnetic fluctuations predominantly parallel) at ?' ˜ 2. The ?' dependence we observe here may connect various waves at harmonics of the proton gyrofrequency found in different regions of space.

Denton, R. E.; Engebretson, M. J.; Keiling, A.; Walsh, A. P.; Gary, S. P.; DéCréAu, P. M. E.; Cattell, C. A.; RèMe, H.

2010-12-01

109

Characterization of mechanical-technological steel properties by Non Linear Harmonics Analysis within the production line  

NASA Astrophysics Data System (ADS)

Mechanical-technological quantities are used to characterize steel and its quality. Here in particular tensile strength, yield strength and anisotropy values are considered. To measure these quantities the magnetoinductive Non Linear Harmonics Analysis (NLHA) has been developed. Its working principle is discussed together with the procedure for measuring, evaluation and calibration. Due to its electromagnetic character the method is fast and less than two seconds are needed per measuring point. Results for non destructive determination of tensile and yield strength as well as anisotropy values within the production line of a steel company are given.

Stegemann, D.; Reimche, W.; Heutling, B.; Krys, A.; Feiste, K. L.; Kroos, J.; Stolzenberg, M.; Westkämper, G.; Angerer, R.

1999-12-01

110

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

NASA Technical Reports Server (NTRS)

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.

Usikov, D. A.

1979-01-01

111

Time and structural crosscorrelation image analysis of microscopic volumes, simultaneously recorded with second harmonic generation, third harmonic generation, and multiphoton excitation fluorescence microscopy  

NASA Astrophysics Data System (ADS)

Our newly developed multimodal microscope enables simultaneous collection of second harmonic generation (SHG), third harmonic generation (THG) and multiphoton excitation fluorescence (MPF) signals. The signals can be generated within different or the same intercellular structures. In comparing two signals, traditional methods of image crosscorrelation analysis using Pearson's coefficient provide a general parameter as to whether the images are similar, however it does not give detailed information about correlation of different structures inside the images. We present here a new technique that employs a pixel by pixel analysis over an entire area or volume that is used to correlate the structures appearing in the images. The result of the analysis reveals structures within the sample that are generated by both nonlinear signals as well as highlighting the structures that are generated by only one of the nonlinear signals. The algorithm provides a means to colocalize different structures revealed by the different nonlinear contrast mechanisms. Structural correlation maps are useful in identifying the origin of structures in one nonlinear contrast mechanism when the origin of structures in another is known. Image analysis has also been exploited for sequences of images taken in time. The intensity fluctuations in time for each pixel reveal regions of intense physiological activity in biological samples. Correlation of time dependent fluctuations from different pixels in the image time series allows construction of the structural map that undergoes similar time behavior or appears out of phase. These structural correlation analysis techniques are demonstrated based on polystyrene beads and cardiomyocytes.

Greenhalgh, Catherine; Cisek, Richard; Prent, Nicole; Major, Arkady; Aus de Au, Juerg; Squier, Jeff; Barzda, Virginijus

2005-09-01

112

Physics: A New Reactor Physics Analysis Toolkit  

SciTech Connect

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

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

2011-06-01

113

Texture analysis applied to second harmonic generation image data for ovarian cancer classification  

NASA Astrophysics Data System (ADS)

Remodeling of the extracellular matrix has been implicated in ovarian cancer. To quantitate the remodeling, we implement a form of texture analysis to delineate the collagen fibrillar morphology observed in second harmonic generation microscopy images of human normal and high grade malignant ovarian tissues. In the learning stage, a dictionary of "textons"-frequently occurring texture features that are identified by measuring the image response to a filter bank of various shapes, sizes, and orientations-is created. By calculating a representative model based on the texton distribution for each tissue type using a training set of respective second harmonic generation images, we then perform classification between images of normal and high grade malignant ovarian tissues. By optimizing the number of textons and nearest neighbors, we achieved classification accuracy up to 97% based on the area under receiver operating characteristic curves (true positives versus false positives). The local analysis algorithm is a more general method to probe rapidly changing fibrillar morphologies than global analyses such as FFT. It is also more versatile than other texture approaches as the filter bank can be highly tailored to specific applications (e.g., different disease states) by creating customized libraries based on common image features.

Wen, Bruce L.; Brewer, Molly A.; Nadiarnykh, Oleg; Hocker, James; Singh, Vikas; Mackie, Thomas R.; Campagnola, Paul J.

2014-09-01

114

Three-dimensional analysis of harmonic generation in high-gain free-electron lasers  

PubMed

In a high-gain free-electron laser (FEL) employing a planar undulator, strong bunching at the fundamental wavelength can drive substantial bunching and power levels at the harmonic frequencies. In this paper we investigate the three-dimensional evolution of harmonic radiation based on the coupled Maxwell-Klimontovich equations that take into account nonlinear harmonic interactions. Each harmonic field is a sum of a linear amplification term and a term driven by nonlinear harmonic interactions. After a certain stage of exponential growth, the dominant nonlinear term is determined by interactions of the lower nonlinear harmonics and the fundamental radiation. As a result, the gain length, transverse profile, and temporal structure of the first few harmonics are eventually governed by those of the fundamental. Transversely coherent third-harmonic radiation power is found to approach 1% of the fundamental power level for current high-gain FEL projects. PMID:11102089

Huang; Kim

2000-11-01

115

Analysis of wire scatterers with nonlinear or time-harmonic loads in the frequency domain  

Microsoft Academic Search

The time-harmonic scattering properties of wire scatterers with nonlinear or time-harmonic loads are analyzed in the frequency domain. First, the scattering problem is treated as a network problem that is analyzed by the method of moments. Then, the harmonic balance technique is applied in the nonlinear load case, and the conversion matrix technique is applied in the time-harmonic load case.

Chien-Chang Huang; Tah-Hsiung Chu

1993-01-01

116

Fourier Analysis in Introductory Physics  

ERIC Educational Resources Information Center

In an after-dinner talk at the fall 2005 meeting of the New England chapter of the AAPT, Professor Robert Arns drew an analogy between classical physics and Classic Coke. To generations of physics teachers and textbook writers, classical physics was the real thing. Modern physics, which in introductory textbooks "appears in one or more extra…

Huggins, Elisha

2007-01-01

117

Passive Harmonic Filters for Medium-Voltage Industrial Systems: Practical Considerations and Topology Analysis  

Microsoft Academic Search

Nowadays, passive harmonic filters are the preferred mitigation scheme for harmonics in power systems. Several types of harmonic filters are available, which are installed according to system topology and to the engineer's judgment. The purpose of this paper is to provide comprehensive information about the most common passive filters and to clarify the design and practical considerations. It compares the

Alexandre B. Nassif; Wilsun Xu

2007-01-01

118

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

E-print Network

Physics and Physical Oceanography Data Report 2004-1 Analysis of Physical Oceanographic Data from Department of Physics and Physical Oceanography Memorial University of Newfoundland St. John's, Newfoundland-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity

deYoung, Brad

119

Quantitative analysis on collagen of dermatofibrosarcoma protuberans skin by second harmonic generation microscopy.  

PubMed

Dermatofibrosarcoma protuberans (DFSP) is a skin cancer usually mistaken as other benign tumors. Abnormal DFSP resection results in tumor recurrence. Quantitative characterization of collagen alteration on the skin tumor is essential for developing a diagnostic technique. In this study, second harmonic generation (SHG) microscopy was performed to obtain images of the human DFSP skin and normal skin. Subsequently, structure and texture analysis methods were applied to determine the differences in skin texture characteristics between the two skin types, and the link between collagen alteration and tumor was established. Results suggest that combining SHG microscopy and texture analysis methods is a feasible and effective method to describe the characteristics of skin tumor like DFSP. SCANNING 9999:XX-XX, 2014. © 2014 Wiley Periodicals, Inc. PMID:25369371

Wu, Shulian; Huang, Yudian; Li, Hui; Wang, Yunxia; Zhang, Xiaoman

2014-11-01

120

Physics of Baseball Bats - An Analysis  

Microsoft Academic Search

An analysis of the physics of baseball bats is presented in this study. The analysis compares the performance of aluminum and wooden baseball bats. Novel experimental approaches to indirectly quantify the performance of these bats have been implemented. The analysis also considers various aspects of baseball including the physical dimensions of the baseball fields, ball exit speed ratio, moment of

N. M. Ravindra; Sushil K. Sikh; Ivan Padron

2009-01-01

121

Spherical harmonic analysis of the CRUST 2.0 global crustal model  

NASA Astrophysics Data System (ADS)

The spherical harmonic analysis of the 2?×2? density and stratification information contained in the global crustal model CRUST 2.0 is presented from the viewpoint of gravity field recovery and interpretation. Using a standard Airy/Heiskanen (A/H) isostatic hypothesis and a radially distributed compensation mechanism, two models of topographic/isostatic (t/i) potential harmonic coefficients are obtained up to degree and order 90. The CRUST-derived coefficients are compared with the spectrum of uncompensated topography, with the EGM96 observed gravity field, and with the t/i spectrum based on an A/H hypothesis with a constant compensation depth of 30 km. The signal degree variances of both CRUST models decrease quite smoothly towards degree 90, while the seven-layer model approaches the EGM96 spectrum for degrees 80 90. The significant deviation of the CRUST spectra from the A/H combined spectrum may prove of relevance to local and regional applications investigating the validity of current isostatic hypotheses.

Tsoulis, D.

2004-09-01

122

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

SciTech Connect

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. __________________________________________________

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; Harvey, R W

2009-12-01

123

Fourier Analysis in Introductory Physics  

NASA Astrophysics Data System (ADS)

In an after-dinner talk at the fall 2005 meeting of the New England chapter of the AAPT, Professor Robert Arns drew an analogy between classical physics and Classic Coke. To generations of physics teachers and textbook writers, classical physics was the real thing. Modern physics, which in introductory textbooks "appears in one or more extra chapters at the end of the book, … is a divertimento that we might get to if time permits." Modern physics is more like vanilla or lime Coke, probably a fad, while "Classic Coke is part of your life; you do not have to think about it twice."

Huggins, Elisha

2007-01-01

124

Symmetry Analysis of ZnSe(100) Surface in Air By Second Harmonic Generation  

E-print Network

Polarized and azimuthal dependencies of optical second harmonics generation (SHG) at the surface of noncentrosymmetric semiconductor crystals have been measured on polished surfaces of ZnSe(100), using a fundamental wavelength of 1.06$\\mu m$. The SHG intensity patterns were analyzed for all four combination of p- and s-polarized incidence and output, considering both the bulk and surface optical nonlinearities in the electric dipole approximation. We found that the measurement using $S_{in}-S_{out}$ is particularly useful in determining the symmetry of the oxdized layer interface, which would lower the effective symmetry of the surface from $C_{4v}$ to $C_{2v}.$ We also have shown that the [011] and [0$\\bar{1}$1] directions can be distinguished through the analysis of p-incident and p-output confugration.

Song, X; Maripuu, R; Siegbahn, Kai; Song, Xiangyang; Neumann, Arnold; Maripuu, Rein; Siegbahn, Kai

2002-01-01

125

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

PubMed

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

Berco, Dan; Hu, Chin-Kun

2014-11-15

126

Higher harmonic control analysis for vibration reduction of helicopter rotor systems  

NASA Technical Reports Server (NTRS)

An advanced higher harmonic control (HHC) analysis has been developed and applied to investigate its effect on vibration reduction levels, blade and control system fatigue loads, rotor performance, and power requirements of servo-actuators. The analysis is based on a finite element method in space and time. A nonlinear time domain unsteady aerodynamic model, based on the indicial response formulation, is used to calculate the airloads. The rotor induced inflow is computed using a free wake model. The vehicle trim controls and blade steady responses are solved as one coupled solution using a modified Newton method. A linear frequency-domain quasi-steady transfer matrix is used to relate the harmonics of the vibratory hub loads to the harmonics of the HHC inputs. Optimal HHC is calculated from the minimization of the vibratory hub loads expressed in term of a quadratic performance index. Predicted vibratory hub shears are correlated with wind tunnel data. The fixed-gain HHC controller suppresses completely the vibratory hub shears for most of steady or quasi-steady flight conditions. HHC actuator amplitudes and power increase significantly at high forward speeds (above 100 knots). Due to the applied HHC, the blade torsional stresses and control loads are increased substantially. For flight conditions where the blades are stalled considerably, the HHC input-output model is quite nonlinear. For such cases, the adaptive-gain controller is effective in suppressing vibratory hub loads, even though HHC may actually increase stall areas on the rotor disk. The fixed-gain controller performs poorly for such flight conditions. Comparison study of different rotor systems indicates that a soft-inplane hingeless rotor requires less actuator power at high speeds (above 130 knots) than an articulated rotor, and a stiff-inplane hingeless rotor generally requires more actuator power than an articulated or a soft-inplane hingeless rotor. Parametric studies for a hingeless rotor operating in a transition flight regime and for an articulated rotor operating at the level-flight boundary (high speed and high thrust conditions) indicate that blade parameters including flap, lag, torsion stiffness distributions, linear pretwist, chordwise offset of center-of-mass from elastic axis and chordwise offset of elastic axis from aerodynamic center can be selected to minimize the actuator power requirements for HHC.

Nguyen, Khanh Q.

1994-01-01

127

On the physics of harmonic injection in a traveling wave tube  

Microsoft Academic Search

The physics of signal injection to shape the output spectrum in a traveling wave tube (TWT) is studied using an analytic solution to the approximate nonlinear S-MUSE model and with the large signal code LATTE. The results verify the long-standing conjecture that a frequency canceled by signal injection is composed of a component due to the injected signal and a

John G. Wohlbier; John H. Booske; Ian Dobson

2004-01-01

128

Teaching Harmonic Motion in Trigonometry: Inductive Inquiry Supported by Physics Simulations  

ERIC Educational Resources Information Center

In this article, the authors present a lesson whose goal is to utilise a scientific environment to immerse a trigonometry student in the process of mathematical modelling. The scientific environment utilised during this activity is a physics simulation called "Wave on a String" created by the PhET Interactive Simulations Project at Colorado…

Sokolowski, Andrzej; Rackley, Robin

2011-01-01

129

[Harmonic imaging analysis for assessment of morphological changes in mini-pig alveolar bone by normal and increased functional load].  

PubMed

The aim of the study was to reveal the mastication forces effect on the microstructure of mandible bone tissue of mini-pigs by Fouirier harmonic imaging analysis of bone sections images of back scattered electrons and assessment of calcium and phosphorous distribution maps obtained by roentgenofluorescence technique. The results showed that by higher functional loads not only the total content of mineral elements in the bone matrix increased but also the of the low-frequency harmonics in the image spectrum indicating structural heterogeneity decrease in bone mineralization. PMID:25588332

Guseva, I E; Zhitkov, M Iu; Loginova, N K; Mokhov, A V

2014-01-01

130

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

NASA Astrophysics Data System (ADS)

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.

Heo, YongHwa; Kim, Kwang-joon

2015-02-01

131

Application of harmonic analysis of water levels to determine vertical hydraulic conductivities in clay-rich aquitards.  

PubMed

A harmonic analysis method was used to determine vertical hydraulic conductivities (Kv) in geologic media between vertically separated piezometers using water level measurements. In this method, each water level time series was filtered and then decomposed using harmonic analysis into a sum of trigonometric components. The phase and amplitude of each harmonic function were calculated. These data were used to estimate Kv values between vertically separated data sets assuming one-dimensional transient flow. The method was applied to water level data collected from nested piezometers at two thick clay-rich till aquitards in Saskatchewan, Canada. At one site, routine water levels were measured in 12 piezometers (installed between 1 and 29 m below ground surface) since installation (1995). At the other site, water levels were measured in seven piezometers (installed between 4 and 53 m below ground surface) since installation (1998-1999). The Kv calculated using harmonic analysis decreased with depth below the water table at both sites, approaching matrix estimates of hydraulic conductivity between 10 and 11 m and between 21 and 43 m below ground surface. These depths reflected the depth of extensive vertical fracturing at the sites and showed that the depth of fracturing may be site specific. PMID:12873014

Boldt-Leppin, Brigitte E J; Hendry, M Jim

2003-01-01

132

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

133

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

Microsoft Academic Search

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

FREDRIC J. HARRIS

1978-01-01

134

Sensorless rotor position estimation through current signature analysis based on rotor saliency harmonic  

Microsoft Academic Search

This paper presents a new technique for estimating the rotor position from the stator current by evaluating rotor saliency harmonics due to rotor slotting effects. These harmonics arise independent of speed and any time-varying machine parameters. Therefore, the proposed technique can be used to estimate the actual rotation of the rotor versus the stator in the time domain using filters

C. Kral; J. V. Gragger; F. Pirker; G. Pascoli

2006-01-01

135

[Simulation and analysis of second-harmonic signal based on tunable diode laser absorption spectroscopy].  

PubMed

Tunable diode laser absorption spectroscopy (TDLAS) is a new gas detection technique developed recently with high spectral resolution, high sensitivity and fast time response. The second-harmonic signal of wavelength modulation spectroscopy (WMS) is often used as the detection signal for gas concentration inversion. Using Simulink, a visual modeling and simulation platform, the authors simulated the WMS signal based on TDLAS, and got the second-harmonic signal by using lock-in amplifier algorithm. Digital orthogonal algorithm was studied in this paper. The relationship between second-harmonic signals and the modulation indexes was analyzed by comparing changes of second-harmonic under different modulation indexes, in order to find out the optimized parameters for second-harmonic detection. PMID:23841390

Li, Han; Liu, Jian-Guo; He, Ya-Bai; He, Jun-Feng; Yao, Lu; Xu, Zhen-Yu; Chen, Jiu-Ying; Yuan, Song; Kan, Rui-Feng

2013-04-01

136

A development environment for visual physics analysis  

NASA Astrophysics Data System (ADS)

The Visual Physics Analysis (VISPA) project integrates different aspects of physics analyses into a graphical development environment. It addresses the typical development cycle of (re-)designing, executing and verifying an analysis. The project provides an extendable plug-in mechanism and includes plug-ins for designing the analysis flow, for running the analysis on batch systems, and for browsing the data content. The corresponding plug-ins are based on an object-oriented toolkit for modular data analysis. We introduce the main concepts of the project, describe the technical realization and demonstrate the functionality in example applications.

Bretz, H.-P.; Brodski, M.; Erdmann, M.; Fischer, R.; Hinzmann, A.; Klimkovich, T.; Klingebiel, D.; Komm, M.; Lingemann, J.; Müller, G.; Münzer, T.; Rieger, M.; Steggemann, J.; Winchen, T.

2012-08-01

137

Spherical harmonic analysis of the sound radiation from omnidirectional loudspeaker arrays  

NASA Astrophysics Data System (ADS)

Omnidirectional sound sources are widely used in room acoustics. These devices are made up of loudspeakers mounted on a spherical or polyhedral cabinet, where the dodecahedral shape prevails. Although such electroacoustic sources have been made readily available to acousticians by many manufacturers, an in-depth investigation of their vibroacoustic behavior has not been provided yet. In order to fulfill this lack, this paper presents a theoretical study of the sound radiation from omnidirectional loudspeaker arrays, which is carried out by using a mathematical model based on the spherical harmonic analysis. Eight different loudspeaker arrangements on the sphere are considered: the well-known five Platonic solid layouts and three extremal system layouts. The latter possess useful properties for spherical loudspeaker arrays used as directivity controlled sound sources, so that these layouts are included here in order to investigate whether or not they could be of interest as omnidirectional sources as well. It is shown through a comparative analysis that the dodecahedral array leads to the lowest error in producing an omnidirectional sound field and to the highest acoustic power, which corroborates the prevalence of such a layout. In addition, if a source with less than 12 loudspeakers is required, it is shown that tetrahedra or hexahedra can be used alternatively, whereas the extremal system layouts are not interesting choices for omnidirectional loudspeaker arrays.

Pasqual, A. M.

2014-09-01

138

Modeling, analysis, and design of RF LDMOS devices using harmonic-balance device simulation  

Microsoft Academic Search

This paper describes how device simulation may be used for the modeling, analysis, and design of radio-frequency (RF) laterally diffused metal-oxide-semiconductor (LDMOS) transistors. Improvements to device analysis needed to meet the requirements of RF devices are discussed. Key modeling regions of the LDMOS device are explored and important physical effects are characterized. The LDMOS model is compared to dc and

F. M. Rotella; G. Ma; Z. Yu; R. W. Dutton

2000-01-01

139

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

NASA Technical Reports Server (NTRS)

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.

Figueroa-Vinas, Adolfo

2013-01-01

140

Non-Characteristic Harmonics Analysis of the ITER Pulsed Power Supply  

NASA Astrophysics Data System (ADS)

The ITER pulsed power supply system will be operated in non-ideal conditions including an asymmetric firing angle, an unbalanced AC supply and an unbalanced AC side impedance of the transformer. In this study the switching functions approach is used to calculate non-characteristic harmonics in ITER, possibly caused by an AC-DC convertor in non-ideal conditions. A PSCAD simulation model is set up to study the non-characteristic harmonics in those non-ideal conditions. It is found that the non-characteristic harmonic does appear and the simulation result is in accordance with the calculating strategy.

Yang, Wei; Xu, Liuwei; Fu, Peng; Lu, Huawei; Sheng, Zhicai

2009-08-01

141

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

NASA Astrophysics Data System (ADS)

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.

Marvian, Iman; Spekkens, Robert W.

2014-12-01

142

Theoretical analysis of Cherenkov third harmonic generation via two cascaded ?(2) processes in a waveguide  

NASA Astrophysics Data System (ADS)

We report a comprehensive numerical study of a type of quasi-phase-matched Cherenkov third harmonic generation in a nonlinear waveguide, and this Cherenkov third harmonic generation consists of a guided-to-guided second harmonic generation cascaded with a guided-to-radiated sum-frequency generation. Following the coupled-mode theory, the temperature-detuning characteristics of third harmonic (TH) radiation under different pumping-power densities were studied. TH power dependences on interaction length have been discussed as well, which includes three situations: without reciprocal vector participating, and forward and backward reciprocal vector participating. In addition, we demonstrate that the Cherenkov angle of each TH radiation is not sensitive to the temperature variation.

Chen, C. D.; Hu, X. P.

2014-10-01

143

Spherical cap harmonic analysis of Super Dual Auroral Radar Network (SuperDARN) observations for generating maps of ionospheric convection  

Microsoft Academic Search

A spherical cap harmonic analysis (SCHA) technique is introduced for mapping the 2-D high-latitude ionospheric convection pattern based on Super Dual Auroral Radar Network (SuperDARN) velocity measurements. The current method for generating such maps is the FIT technique which generates global-scale maps over the entire convection region. This is accomplished by combining observations with a statistical model to prevent unphysical

R. A. D. Fiori; D. H. Boteler; A. V. Koustov; G. V. Haines; J. M. Ruohoniemi

2010-01-01

144

A study of the fundamental principles to power system harmonic  

Microsoft Academic Search

This paper is to present the harmonic phenomenon. The Fourier series is the tool for harmonic analysis in order to interpret waveforms behavior due to nonlinear loads is carried out. Some harmonics measurements for nonlinear loads are also observed. The harmonics theory, definition of harmonic quantities, related harmonics problems in power distribution systems are explained. Also, filter applications such as

M. Izhar; C. M. Hadzer; S. Masri; S. Idris

2003-01-01

145

Spherical cap harmonic analysis of the Arctic ionospheric TEC for one solar cycle  

NASA Astrophysics Data System (ADS)

knowledge of the Arctic ionosphere total electron content (TEC) and its variations has scientific relevance due to the unique characteristics of the polar ionosphere. Understanding the Arctic TEC is also important for precise positioning and navigation in the Arctic. This study utilized the spherical cap harmonic analysis (SCHA) method to map the Arctic TEC for the most recent solar cycle from 2000 to 2013 and analyzed the distributions and variations of the Arctic TEC at different temporal and spatial scales. Even with different ionosphere conditions during the solar cycle, the results showed that the existing International Global Navigation Satellite Systems Service stations are sufficient for mapping the Arctic TEC. The SCHA method provides adequate accuracy and resolution to analyze the spatiotemporal distributions and variations of the Arctic TEC under different ionosphere conditions and to track ionization patches in this polar region (e.g., the ionization event of 26 September 2011). The results derived from the SCHA model were compared to direct observations using the Super Dual Auroral Radar Network radar. The SCHA method is able to predict the TEC in the long and short terms. This paper presented a long-term prediction with a relative uncertainty of 75% for a latency of one solar cycle and a short-term prediction with errors of ±2.2 total electron content units (TECUs, 1 TECU = 1016 el m-2), ±3.8 TECU, and ±4.8 TECU for a latency of 1, 2, and 3 days, respectively. The SCHA is an effective method for mapping, predicting, and analyzing the Arctic TEC.

Liu, Jingbin; Chen, Ruizhi; An, Jiachun; Wang, Zemin; Hyyppa, Juha

2014-01-01

146

Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration  

SciTech Connect

Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing requirements by increasing harvested power, shifting optimal conditioning impedance, inducing significant voltage supply fluctuations and ultimately rendering idealized sinusoidal and random analyses insufficient.

Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.

2013-07-01

147

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

NASA Astrophysics Data System (ADS)

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.

Al-shyyab, A.; Kahraman, A.

2005-01-01

148

Dynamic Analysis of Wind Turbine Planetary Gears Using an Extended Harmonic Balance Approach: Preprint  

SciTech Connect

The dynamics of wind turbine planetary gears with gravity effects are investigated using an extended harmonic balance method that extends established harmonic balance formulations to include simultaneous internal and external excitations. The extended harmonic balance method with arc-length continuation and Floquet theory is applied to a lumped-parameter planetary gear model including gravity, fluctuating mesh stiffness, bearing clearance, and nonlinear tooth contact to obtain the planetary gear dynamic response. The calculated responses compare well with time domain integrated mathematical models and experimental results. Gravity is a fundamental vibration source in wind turbine planetary gears and plays an important role in system dynamics, causing hardening effects induced by tooth wedging and bearing-raceway contacts. Bearing clearance significantly reduces the lowest resonant frequencies of translational modes. Gravity and bearing clearance together lowers the speed at which tooth wedging occurs lower than the resonant frequency.

Guo, Y.; Keller, J.; Parker, R. G.

2012-06-01

149

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

NASA Astrophysics Data System (ADS)

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.

Wei, Dong; Aketagawa, Masato

2014-12-01

150

Symbolic Vector Analysis in Plasma Physics  

SciTech Connect

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.

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

1997-10-09

151

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

Microsoft Academic Search

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

Hansang Lee; Gilsoo Jang; Byungmoon Han

2010-01-01

152

Harmonic wave analysis of conductor corona current based on wide frequency band measurement  

Microsoft Academic Search

Corona current is one of important corona characteristic research contents. In order to analyze conductor corona current harmonic wave characteristic, a corona current measurement system is developed. The synchronous collect of the voltage and current signal is realized by the GPS technology. The corona current signal is transmitted to the lower computer through the wireless network. And the current signal

Fangcheng Lu; Shaohua You; Yunpeng Liu; Lei Zhu

2011-01-01

153

Analysis of second-harmonic generation by primary horizontal shear modes in layered planar structures with imperfect interfaces  

NASA Astrophysics Data System (ADS)

This paper describes modeling of second-harmonic generation by the primary horizontal shear (SH) mode propagation in layered planar structures with imperfect interfaces. Due to the elastic nonlinearity of the solid, there are second-order bulk driving forces in each solid layer and a second-order stress tensor at each surface/interface, accompanying the primary SH mode propagation. Within second-order perturbation, these bulk driving forces and stress tensors can be thought of as the excitation source of a series of double frequency Lamb modes (DFLMs) in terms of the approach of modal expansion analysis for waveguide excitation. The equation governing the expansion coefficient of each DFLM is developed. It is found that the expansion coefficient of each DFLM is directly coupled with the interfacial properties, characterized by the finite normal and tangential interfacial stiffnesses. Especially, the phase velocity mismatching between the primary SH mode and the DFLM, caused by the degradation of interface (with respect to the case of the perfect interface), can remarkably influence the efficiency of second-harmonic generation by the primary SH mode propagation. The potential is discussed of using the effect of second-harmonic generation by the primary SH mode propagation to evaluate the interfacial properties of layered structures.

Deng, Mingxi; Xiang, Yanxun

2013-01-01

154

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

ERIC Educational Resources Information Center

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.

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

2004-01-01

155

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

NASA Astrophysics Data System (ADS)

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.

Leadenham, S.; Erturk, A.

2014-11-01

156

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)

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.

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

2014-11-01

157

Harmonic analysis of tides and tidal currents in South San Francisco Bay, California  

USGS Publications Warehouse

Water level observations from tide stations and current observations from current-meter moorings in South San Francisco Bay (South Bay), California have been harmonically analysed. At each tide station, 13 harmonic constituents have been computed by a least-squares regression without inference. Tides in South Bay are typically mixed; there is a phase lag of approximately 1 h and an amplification of 1??5 from north to south for a mean semi-diurnal tide. Because most of the current-meter records are between 14 and 29 days, only the five most important harmonics have been solved for east-west and north-south velocity components. The eccentricity of tidal-current ellipse is generally very small, which indicates that the tidal current in South Bay is strongly bidirectional. The analyses further show that the principal direction and the magnitude of tidal current are well correlated with the basin bathymetry. Patterns of Eulerian residual circulation deduced from the current-meter data show an anticlockwise gyre to the west and a clockwise gyre to the east of the main channel in the summer months due to the prevailing westerly wind. Opposite trends have been observed during winter when the wind was variable. ?? 1985.

Cheng, R.T.; Gartner, J.W.

1985-01-01

158

Operational modal analysis of a ship model in the presence of harmonic excitation  

NASA Astrophysics Data System (ADS)

A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm (NExT-ERA) is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.

Xu, Junchen; Hong, Ming; Liu, Xiaobing

2013-03-01

159

Analysis and projections of physics in Chile  

NASA Astrophysics Data System (ADS)

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.

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

2008-11-01

160

Strong-Field Many-Body Physics and the Giant Enhancement in the High-Harmonic Spectrum of Xenon  

E-print Network

We resolve an open question about the origin of the giant enhancement in the high-harmonic generation (HHG) spectrum of atomic xenon around 100 eV. By solving the many-body time-dependent Schr\\"odinger equation with all orbitals in the 4d, 5s, and 5p shells active, we demonstrate the enhancement results truly from collective many-body excitation induced by the returning photoelectron via two-body interchannel interactions. Without the many-body interactions, which promote a 4d electron into the 5p vacancy created by strong-field ionization, no collective excitation and no enhancement in the HHG spectrum exist.

Pabst, Stefan

2013-01-01

161

BESIU Physical Analysis on Hadoop Platform  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

162

Inelastic neutron scattering analysis of low-frequency motions in proteins: Harmonic and damped harmonic models of bovine pancreatic tryspin inhibitor  

NASA Astrophysics Data System (ADS)

Inelastic neutron scattering spectra are calculated from harmonic and damped harmonic models of the internal dynamics of a small protein, the bovine pancreatic trypsin inhibitor (BPTI). Numerical Fourier transformation of the intermediate scattering function Fvibinc (q, t) is used to calculate the inelastic scattering. This permits the inclusion of multiphonon scattering and frictional damping effects. Although for a typical experimental configuration, the multiphonon contribution does not significantly alter the form of the scattering at frequencies below about 30 cm-1, it does have a significant effect on the scattering intensity at higher frequencies. Frictional damping is introduced into the harmonic model by assuming that each mode acts as an independent damped Langevin oscillator. With this model and the assumption that the lowest frequency modes are overdamped while the higher frequency modes are underdamped, improved agreement with the experimental BPTI powder results is obtained. The measured scattering from BPTI in solution shows increased intensity at frequencies below 50 cm-1 relative to the powder results. The solution scattering profile can be reproduced approximately by the addition of overdamped Langevin oscillator normal modes to the dynamic model in best agreement with the powder data. Several other aspects of neutron scattering from proteins are examined. Anisotropy in the harmonic resolution broadened scattering is demonstrated. Spectra calculated assuming classical equations of motion are shown to agree with those calculated with the full quantum-mechanical dynamical model. Translational diffusion broadening is found to be small compared to the instrumental resolution broadening for the range of scattering wave vectors of interest. The contribution of the coherent scattering to the measured intensity is calculated for the case of a partially hydrated protein. Under typical experimental conditions, the measured cross sections are dominated by the incoherent scattering and the self part of the coherent scattering, a result that justifies the comparison of experimental data with calculated incoherent scattering spectra.

Smith, Jeremy; Cusack, Stephen; Tidor, Bruce; Karplus, Martin

1990-09-01

163

Workshop Physics Activity Guide, Module 2: Mechanics II, Momentum, Energy, Rotational and Harmonic Motion, and Chaos (Units 8 - 15)  

NASA Astrophysics Data System (ADS)

The Workshop Physics Activity Guide is a set of student workbooks designed to serve as the foundation for a two-semester calculus-based introductory physics course. It consists of 28 units that interweave text materials with activities that include prediction, qualitative observation, explanation, equation derivation, mathematical modeling, quantitative experiments, and problem solving. Students use a powerful set of computer tools to record, display, and analyze data, as well as to develop mathematical models of physical phenomena. The design of many of the activities is based on the outcomes of physics education research. The Workshop Physics Activity Guide is supported by an Instructor's Website that: (1) describes the history and philosophy of the Workshop Physics Project; (2) provides advice on how to integrate the Guide into a variety of educational settings; (3) provides information on computer tools (hardware and software) and apparatus; and (4) includes suggested homework assignments for each unit. Log on to the Workshop Physics Project website at http://physics.dickinson.edu/ Workshop Physics is a component of the Physics Suite--a collection of materials created by a group of educational reformers known as the Activity Based Physics Group. The Physics Suite contains a broad array of curricular materials that are based on physics education research, including:

    Understanding Physics, by Cummings, Laws, Redish and Cooney (an introductory textbook based on the best-selling text by Halliday/Resnick/Walker) RealTime Physics Laboratory Modules Physics by Inquiry (intended for use in a workshop setting) Interactive Lecture Demonstration Tutorials in Introductory Physics Activity Based Tutorials (designed primarily for use in recitations)

    Laws, Priscilla W.

    2004-05-01

164

Gender and Physics: a Theoretical Analysis  

NASA Astrophysics Data System (ADS)

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.

Rolin, Kristina

165

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

SciTech Connect

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.

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

166

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

NASA Astrophysics Data System (ADS)

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.

Avendaño, Carlos G.; Reyes, J. Adrián

2015-01-01

167

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

NASA Technical Reports Server (NTRS)

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.

Chao, B. F.

1983-01-01

168

Data Analysis Tools for NSTX-U Physics Meeting  

E-print Network

Data Analysis Tools for NSTX-U Bill Davis Stan Kaye Physics Meeting B-318 Aug. 26, 2013 NSTX LLC #12;NSTX-U Monday Physics Meeting­ Data Analysis Tools, Bill Davis (8/26/2013) 2 Overview ·Web tools should be developed? #12;NSTX-U Monday Physics Meeting­ Data Analysis Tools, Bill Davis (8

Princeton Plasma Physics Laboratory

169

Cumulative second-harmonic analysis of ultrasonic Lamb waves for ageing behavior study of modified-HP austenite steel.  

PubMed

The cumulative second-harmonic analysis of ultrasonic Lamb wave has been performed to study the precipitation kinetics and microvoid initiation of ferritic Cr-Ni alloy steel during the ageing process. Ageing of ferritic Cr-Ni alloy materials have been done at 1223 K and 1173 K for different degradation time intervals and air cooled. The results show that the normalized acoustic nonlinearity of Lamb wave increases with the formation of fine precipitates at the early stage of ageing till about 1000 h and keeps as a plateau with the precipitates dynamic balance for a long-term ageing, and then decreases gradually at the final holding time with the coarsening of precipitates and initiation of microvoids. The results also show that the variation of nonlinear Lamb wave follows the same trend as that of hardness in materials. Therefore, the cumulative second-harmonic of ultrasonic Lamb waves has been found to be strongly sensitive to the precipitates behavior and microstructure evolution during the thermal ageing of ferritic Cr-Ni alloy steel. PMID:21680007

Xiang, Yanxun; Deng, Mingxi; Xuan, Fu-Zhen; Liu, Chang-Jun

2011-12-01

170

A method for nonlinear modal analysis and synthesis: Application to harmonically forced and self-excited mechanical systems  

NASA Astrophysics Data System (ADS)

The recently developed generalized Fourier-Galerkin method is complemented by a numerical continuation with respect to the kinetic energy, which extends the framework to the investigation of modal interactions resulting in folds of the nonlinear modes. In order to enhance the practicability regarding the investigation of complex large-scale systems, it is proposed to provide analytical gradients and exploit sparsity of the nonlinear part of the governing algebraic equations. A novel reduced order model (ROM) is developed for those regimes where internal resonances are absent. The approach allows for an accurate approximation of the multi-harmonic content of the resonant mode and accounts for the contributions of the off-resonant modes in their linearized forms. The ROM facilitates the efficient analysis of self-excited limit cycle oscillations, frequency response functions and the direct tracing of forced resonances. The ROM is equipped with a large parameter space including parameters associated with linear damping and near-resonant harmonic forcing terms. An important objective of this paper is to demonstrate the broad applicability of the proposed overall methodology. This is achieved by selected numerical examples including finite element models of structures with strongly nonlinear, non-conservative contact constraints.

Krack, Malte; Panning-von Scheidt, Lars; Wallaschek, Jörg

2013-12-01

171

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

NASA Astrophysics Data System (ADS)

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.

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

172

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

PubMed

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. PMID:23174951

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

173

Nonlinear Analysis of Forced Responses of an Axially Moving Beam by Incremental Harmonic Balance Method  

SciTech Connect

This paper analyzes nonlinear vibration of an axially moving beam subject to periodic lateral forces by Incremental Harmonic Balance (IHB) method. Attention is paid to the fundamental resonance as the force frequency is close to the first frequencies omega{sub 1} of the system. Galerkin method is used to discretize the governing equations and the IHB method is used to illustrate the nonlinear dynamic behavior of the axially moving beam. The stable and unstable periodic solutions for given parameters are determined by the multivariable Floquet theory. Hsu's method is applied for computing the transition matrix at the end of one period. The effects of internal resonance on the beam responses are discussed. The periodic solutions obtained from the IHB method are in good agreement with the results obtained from numerical integration.

Huang, J. L.; Chen, S. H. [Department of Applied Mechanics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Su, R. K. L. [Department of Civil Engineering, University of Hong Kong, Pokfulam (Hong Kong); Lee, Y. Y. [Department of Building and Construction, City University of Hong Kong (Hong Kong)

2010-05-21

174

Analysis of Initial High Harmonic Fast Wave Heating Experiments on NSTX  

NASA Astrophysics Data System (ADS)

The first phase of high harmonic fast wave heating (HHFW) experiments on NSTX has begun. Up to 2 MW of RF power at 30 MHz has been applied to discharges with central electron densities up to 2e13 cm-3, total plasma betas up to 0.05, and on axis toroidal fields of 3 kG. Core electron heating was inferred from spectroscopic measurements when the applied toroidal wave spectrum peaked at about 14 m-1, but not at 7 m-1. The METS 1D single pass integral kinetic wave code is being used to examine the strength of the ion and electron power absorption rates in these plasmas. Effects due to changes in the launched wave spectrum, the relative concentration of different ion species, and the presence of parallel magnetic field gradients will be discussed.

Phillips, C. K.; Wilson, J. R.; Bernabei, S.; Leblanc, B.; Hosea, J. C.; Majeski, R. P.; Menard, J.; Stutman, D.; Ryan, P.; Swain, D.; Smithe, D. N.

2000-10-01

175

Workshop Physics Activity Guide, Module 2: Mechanics II, Momentum, Energy, Rotational and Harmonic Motion, and Chaos (Units 8 - 15)  

Microsoft Academic Search

The Workshop Physics Activity Guide is a set of student workbooks designed to serve as the foundation for a two-semester calculus-based introductory physics course. It consists of 28 units that interweave text materials with activities that include prediction, qualitative observation, explanation, equation derivation, mathematical modeling, quantitative experiments, and problem solving. Students use a powerful set of computer tools to record,

Priscilla W. Laws

2004-01-01

176

Evaluation of the harmonic-analysis method for surface soil heat flux estimation: a case study in Heihe River Basin  

NASA Astrophysics Data System (ADS)

Surface soil heat flux(G0) is an important component of surface energy balance, and it causes large uncertainty in evapotranspiration estimation. In present study, soil heat flux was calculated at different depths based on the harmonic analysis method (HM) using field data in Heihe River Basin, northwestern China. The soil heat fluxes at a certain depth and at the surface were validated by heat-plate measurements and G0 derived from thermal diffusion equation, respectively. Results showed that HM method obtained good result during the daytime, yet the errors were relatively large at nighttime mostly due to the assumption of symmetry of G0 during daytime and nighttime. Moreover, a regional G0 map was provided based on remote sensing data. This study highlighted the simplicity of HM method and its potential application in large spatial scale mapping. Its internal limit was also discussed here.

Li, Nana; Jia, Li; Zheng, Chaolei

2014-12-01

177

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

NASA Technical Reports Server (NTRS)

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.

Kottapalli, Sesi; Leyland, Jane

1991-01-01

178

A novel double-circuit-rotor balanced induction motor for improved slip-energy recovery drive performance. Part 2: Experimental verification and harmonic analysis  

Microsoft Academic Search

The merits of the new slip-energy recovery drive system that has been proposed in Part 1 of this paper is demonstrated here. Experimental work is carried out to verify the simulated models of the proposed and conventional systems. Furthermore, harmonic analysis of both systems is conducted analytically and confirmed numerically using the FFT. The main feature of the new proposed

W. S. Zakaria; A. A. Shaltout; S. R. Alwash

1996-01-01

179

Physical foundation of quantitative Auger analysis  

NASA Astrophysics Data System (ADS)

The possibility of using an Auger peak height in the dN (E) /dE spectrum and an integrated N (E) spectrum as a measure of the Auger current is discussed and necessary relations are presented. The methods of the background determination are reviewed and discussed. The relation between the Auger current and the atomic cancentration of a corresponding sample component is derived and the state of art in the field of theoretical and experimental determination of factors appearing in this relation (ionization cross-section, Auger transition probability. backscattering factor, and inelastic mean free path of Auger electrons) is presented. Approaches to the quantitative Auger analysis (QAA) of homogeneous, isotropic samples, including corrections for matrix factors, are presented and discussed. Problems arising when heterogeneous samples are analyzed are discussed and practical approaches to such an analysis are presented. The role of crystalline effects (the dependence of the Auger signal from crystalline samples on the direction of the primary electron beam and angular distribution of Auger electron emission from such samples) in QAA is discussed and examples of such crystalline effects are presented together with their physical foundation. Some rules are suggested allowing the quantitative Auger analysis to be performed with the smallest possible error.

Mróz, Stefan

1994-08-01

180

Analysis of second-harmonic-generation microscopy in a mouse model of ovarian carcinoma  

NASA Astrophysics Data System (ADS)

Second-harmonic-generation (SHG) imaging of mouse ovaries ex vivo was used to detect collagen structure changes accompanying ovarian cancer development. Dosing with 4-vinylcyclohexene diepoxide and 7,12-dimethylbenz[a]anthracene resulted in histologically confirmed cases of normal, benign abnormality, dysplasia, and carcinoma. Parameters for each SHG image were calculated using the Fourier transform matrix and gray-level co-occurrence matrix (GLCM). Cancer versus normal and cancer versus all other diagnoses showed the greatest separation using the parameters derived from power in the highest-frequency region and GLCM energy. Mixed effects models showed that these parameters were significantly different between cancer and normal (P<0.008). Images were classified with a support vector machine, using 25% of the data for training and 75% for testing. Utilizing all images with signal greater than the noise level, cancer versus not-cancer specimens were classified with 81.2% sensitivity and 80.0% specificity, and cancer versus normal specimens were classified with 77.8% sensitivity and 79.3% specificity. Utilizing only images with greater than of 75% of the field of view containing signal improved sensitivity and specificity for cancer versus normal to 81.5% and 81.1%. These results suggest that using SHG to visualize collagen structure in ovaries could help with early cancer detection.

Watson, Jennifer M.; Rice, Photini F.; Marion, Samuel L.; Brewer, Molly A.; Davis, John R.; Rodriguez, Jeffrey J.; Utzinger, Urs; Hoyer, Patricia B.; Barton, Jennifer K.

2012-07-01

181

Analysis of second-harmonic-generation microscopy in a mouse model of ovarian carcinoma  

PubMed Central

Abstract. Second-harmonic-generation (SHG) imaging of mouse ovaries ex vivo was used to detect collagen structure changes accompanying ovarian cancer development. Dosing with 4-vinylcyclohexene diepoxide and 7,12-dimethylbenz[a]anthracene resulted in histologically confirmed cases of normal, benign abnormality, dysplasia, and carcinoma. Parameters for each SHG image were calculated using the Fourier transform matrix and gray-level co-occurrence matrix (GLCM). Cancer versus normal and cancer versus all other diagnoses showed the greatest separation using the parameters derived from power in the highest-frequency region and GLCM energy. Mixed effects models showed that these parameters were significantly different between cancer and normal (P<0.008). Images were classified with a support vector machine, using 25% of the data for training and 75% for testing. Utilizing all images with signal greater than the noise level, cancer versus not-cancer specimens were classified with 81.2% sensitivity and 80.0% specificity, and cancer versus normal specimens were classified with 77.8% sensitivity and 79.3% specificity. Utilizing only images with greater than of 75% of the field of view containing signal improved sensitivity and specificity for cancer versus normal to 81.5% and 81.1%. These results suggest that using SHG to visualize collagen structure in ovaries could help with early cancer detection. PMID:22894485

Watson, Jennifer M.; Rice, Photini F.; Marion, Samuel L.; Brewer, Molly A.; Davis, John R.; Rodriguez, Jeffrey J.; Utzinger, Urs; Hoyer, Patricia B.; Barton, Jennifer K.

2012-01-01

182

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)

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.

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

2013-01-01

183

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

PubMed

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. PMID:23123244

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

2013-01-15

184

Spatial Harmonic Decomposition as a tool for unsteady flow phenomena analysis  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

185

Spherical harmonic representation of the main geomagnetic field for world charting and investigations of some fundamental problems of physics and geophysics  

NASA Technical Reports Server (NTRS)

Progress in the harmonic analysis of MAGSAT data is reported. Single-day data sets were subdivided into information on the sunrise side of the Earth and information on the sunset side of the Earth. Data for the main and external fields each demonstrate a clear and consistent systematic difference between the sets of data which was determined to be, due to ionospheric currents which differ from the sunset to the sunrise terminator. A toroidal field was analyzed for and determined to be an apparent toroidal field resulting from electric currents concentrated in the two terminators. Progressive elimination of auroral zone data demonstrates that the information presented does not arise from complications due to Birkeland currents.

Barraclough, D. R.; Hide, R.; Leaton, B. R.; Lowes, F. J.; Malin, S. R. C.; Wilson, R. L. (principal investigators)

1982-01-01

186

Learning from physical sequence data Fermat Component Analysis  

E-print Network

Learning from physical sequence data Fermat Component Analysis Efficient high-dimensional inference Fermat Components Analysis Paul Vernaza Daniel D. Lee GRASP Lab University of Pennsylvania May 25, 2010 Paul Vernaza, Daniel D. Lee #12;Learning from physical sequence data Fermat Component Analysis

Vernaza, Paul

187

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

E-print Network

Optimization of high-order harmonic generation by genetic algorithm and wavelet time laser fields by means of the genetic algorithm optimization of the laser-pulse amplitude and phase of the coherent control and enhancement of high-harmonic emission by means of the genetic algo- rithm GA

Chu, Shih-I

188

Harmonic engine  

DOEpatents

A high efficiency harmonic engine based on a resonantly reciprocating piston expander that extracts work from heat and pressurizes working fluid in a reciprocating piston compressor. The engine preferably includes harmonic oscillator valves capable of oscillating at a resonant frequency for controlling the flow of working fluid into and out of the expander, and also preferably includes a shunt line connecting an expansion chamber of the expander to a buffer chamber of the expander for minimizing pressure variations in the fluidic circuit of the engine. The engine is especially designed to operate with very high temperature input to the expander and very low temperature input to the compressor, to produce very high thermal conversion efficiency.

Bennett, Charles L. (Livermore, CA)

2009-10-20

189

PHYSICAL REVIEW A 87, 063406 (2013) Quantitative rescattering theory of high-order harmonic generation for polyatomic molecules  

E-print Network

the example of the CCl4 molecule. In particular, we present a detailed analysis and a treatment for the phase is to test our theory against available experimental data on an example molecule, which we take to be CCl4 of the electron returning wave packet on CCl4, which is our example molecule. Such analysis suggests that an angle

Le, Anh-Thu

190

Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE  

Microsoft Academic Search

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

Rich Pawlowicz; Bob Beardsley; Steve Lentz

2002-01-01

191

Analysis of Interactions between Drifting Plasma Waves in 2DEG Semiconductors and Electromagnetic Space Harmonic Waves using Three-Dimensional Transverse Magnetic Mode Method  

SciTech Connect

A theoretical three-dimensional transverse magnetic (TM) mode analysis to describe the presence of interactions between surface plasma waves of carriers in a two-dimensional electron gas (2DEG) at AlGaAs/GaAs heterostructure and electromagnetic space harmonics slow waves using the so-called interdigital-gated high-electron-mobility-transistor (HEMT) plasma wave devices is presented. First, the device structure and the outline of theoretical formulation to determine the admittance of the interdigital structure are described. Then, the analysis of the space harmonics propagating through the interdigital slow-wave structures is performed. Next, the numerical procedures to solve the integral equations which are used in determining the admittance are explained. Finally, we point out and discuss the main results of the theoretical analysis where an appearance of negative conductance is obtained.

Hashim, Abdul Manaf [Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ahir, Zon Fazlila Mohd [Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Kasai, Seiya; Hashizume, Tamotsu; Hasegawa, Hideki [Research Center for Integrated Quantum Electronics, Hokkaido University North 12 West 8, Sapporo 060-8628 (Japan)

2009-07-07

192

Harmonics and Fourier Series Model  

NSDL National Science Digital Library

The Ejs Harmonics and Fourier Series model displays the sum of harmonics via a Fourier series to yield a new wave. The amplitude of each harmonic as well as the phase of that harmonic can be changed via sliders. In addition, several pre-set functions can be chosen to display. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Harmonics and Fourier Series model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_oscillations_harmonics.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for classical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-11-11

193

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

SciTech Connect

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.

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

2008-03-01

194

Theoretical Analysis for Obtaining Physical Properties of Composite Electrodes  

E-print Network

the electronic conductivity of a composite cathode in a lithium battery, and Saab et al.2 the ionicTheoretical Analysis for Obtaining Physical Properties of Composite Electrodes Parthasarathy M analysis is presented that allows in situ measurements of the physical properties of a composite electrode

Weidner, John W.

195

IEEE TRANSACTIONS ON AUDIO, SPEECH, AND LANGUAGE PROCESSING 1 Harmonic Adaptive Latent Component Analysis of  

E-print Network

Analysis of Audio and Application to Music Transcription Benoit Fuentes, Student Member, IEEE, Roland of automatic music transcription. However those tech- niques are not necessarily suitable for notes having spectra, spectrally convolved with some impulse that defines the pitch. All parameters are estimated

Richard, Gaël

196

An SQL-based approach to physics analysis  

NASA Astrophysics Data System (ADS)

As part of the CERN openlab collaboration a study was made into the possibility of performing analysis of the data collected by the experiments at the Large Hadron Collider (LHC) through SQL-queries on data stored in a relational database. Currently LHC physics analysis is done using data stored in centrally produced "ROOT-ntuple" files that are distributed through the LHC computing grid. The SQL-based approach to LHC physics analysis presented in this paper allows calculations in the analysis to be done at the database and can make use of the database's in-built parallelism features. Using this approach it was possible to reproduce results for several physics analysis benchmarks. The study shows the capability of the database to handle complex analysis tasks but also illustrates the limits of using row-based storage for storing physics analysis data, as performance was limited by the I/O read speed of the system.

Limper, Maaike, Dr

2014-06-01

197

Harmonic engine  

DOEpatents

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.

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

2014-08-19

198

A novel double-circuit-rotor balanced induction motor for improved slip-energy recovery drive performance. II. Experimental verification and harmonic analysis  

Microsoft Academic Search

The merits of the new slip-energy recovery drive system that has been proposed in Part I of this paper (see ibid., vol.11, no.3, p.556-62, 1996) is demonstrated here. Experimental work is carried out to verify the simulated, models of the proposed and conventional systems. Furthermore, harmonic analysis of both systems is conducted analytically and confirmed numerically using the FFT. The

W. S. Zakaria; A. A. Shiiltout; S. R. Alwash

1996-01-01

199

Vibrational subsystem analysis: A method for probing free energies and correlations in the harmonic limit  

PubMed Central

A new vibrational subsystem analysis (VSA) method is presented for coupling global motion to a local subsystem while including the inertial effects of the environment. The premise of the VSA method is a partitioning of a system into a smaller region of interest and a usually larger part referred to as environment. This method allows the investigation of local-global coupling, a more accurate estimation of vibrational free energy contribution for parts of a large system, and the elimination of the “tip effect” in elastic network model calculations. Additionally, the VSA method can be used as a probe of specific degrees of freedom that may contribute to free energy differences. The VSA approach can be employed in many ways, but it will likely be most useful for estimating activation free energies in QM?MM reaction path calculations. Four examples are presented to demonstrate the utility of this method. PMID:19063546

Woodcock, H. Lee; Zheng, Wenjun; Ghysels, An; Shao, Yihan; Kong, Jing; Brooks, Bernard R.

2008-01-01

200

Efficiency assessment of shock wave therapy in patients with pelvic pain employing harmonic analysis of penile bioimpedance.  

PubMed

In searching for novel objective methods to diagnosticate pelvic pain and assess efficiency of analgesic therapy, 37 male patients were examined prior to and after the course of extracorporeal shock wave therapy (5-10 sessions) with the waves directed to projections of prostate and/or crura and shaft of the penis. The repetition rate of mechanical pulses was 3-5 Hz. The range of energy pulse density was 0.09-0.45 mJ/mm(2). The overall number of pulses in a session was 1500-3000 in any treated zone with total energy smaller than 60 J. The applicator was relocated every other series of 300-500 pulses. Effect of the shock wave therapy was assessed according to subjective symptomatic scales: International Prostate Symptom Score, International Index of Erectile Function, Quality of Life, and nociceptive Visual Analog Scale. The objective assessment of shock wave therapy was performed with harmonic analysis of penile bioimpedance variability, which quantitatively evaluated the low-frequency rhythmic and asynchronous activities at rest as well as the total pulsatile activity of the penis. The magnitude of spectrum components of bioimpedance variations was assessed with a novel parameter, the effective impedance. The spectral parameters were measured in 16 patients prior to and after the treatment course. The corresponding control values were measured in the group of healthy patients. Prior to the shock wave therapy course, all spectrum parameters of penile bioimpedance significantly differed from the control (p<0.05). After this course, low-frequency rhythmic and the total pulsatile activity decreased to normal, while asynchronous activity remained significantly different from the normal. The novel objective physiological criteria of pelvic pain diagnostics and efficiency of its treatment reflecting the regional features of circulation and neural activity corresponded to the clinical symptom scaling prior to and after the shock wave course, and on the whole, these criteria corroborated improvement of the patient state after this therapy. PMID:24131011

Khodyreva, L A; Dudareva, A A; Mudraya, I S; Markosyan, T G; Revenko, S V; Kumachev, K V; Logvinov, L A

2013-06-01

201

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)

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.

Sanchez, Braulio V.; Nishihama, Masahiro

1997-01-01

202

Covariant harmonic oscillators: 1973 revisited  

NASA Technical Reports Server (NTRS)

Using the relativistic harmonic oscillator, a physical basis is given to the phenomenological wave function of Yukawa which is covariant and normalizable. It is shown that this wave function can be interpreted in terms of the unitary irreducible representations of the Poincare group. The transformation properties of these covariant wave functions are also demonstrated.

Noz, M. E.

1993-01-01

203

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

ERIC Educational Resources Information Center

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"…

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

2014-01-01

204

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

SciTech Connect

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.

None

2010-01-20

205

Interactive ergonomic analysis of a physically disabled person's workplace  

E-print Network

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

Paris-Sud XI, Université de

206

Dimensional Analysis in Physics and the Buckingham Theorem  

ERIC Educational Resources Information Center

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…

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

2010-01-01

207

Exploratory versus Confirmatory Factor Analysis of Collegiate Physical Fitness.  

ERIC Educational Resources Information Center

Twenty-one variables believed to be important indicators of health related physical fitness were measured on male and female college students between 1991 and 1993 (n=433). Exploratory and confirmatory factor analytic techniques were used in an attempt to derive important components of physical fitness. The exploratory factor analysis identified…

Mead, Tim P.; Legg, David L.

208

Transmission characteristics of cyclotron harmonic waves in plasma  

Microsoft Academic Search

In recent years the importance of cyclotron harmonic waves has become apparent in many branches of plasma physics. For example, it has been demonstrated that they are involved in the anomalously high noise radiation near the electron cyclotron harmonic frequencies that has been observed from thermonuclear fusion study devices, and that they can explain the cyclotron harmonic resonances observed in

F. W. Crawford; H. H. Weiss

1966-01-01

209

Teaching from a Microgravity Environment: Harmonic Oscillator and Pendulum  

Microsoft Academic Search

This presentation reports on an educational experiment flown in January 2009 as part of NASA's Microgravity University program. The experiment flown was an investigation into the properties of harmonic oscillators in reduced gravity. Harmonic oscillators are studied in every introductory physics class. The equation for the period of a harmonic oscillator does not include the acceleration due to gravity, so

Raymond Benge; Charlotte Young; Shirley Davis; Alan Worley; Linda Smith; Amber Gell

2009-01-01

210

On Time: Implications in Physical Modelling and Numerical Analysis  

E-print Network

This presentation examines the issue of 'time' from a multitude of points of consideration. These include (a) philosophy, (b) perception of time and neurology, (c) physics and engineering, (d) mathematics, (e) numerical analysis and computing...

Vassiliadis, Vassilios S

2014-05-17

211

Dirac-harmonic maps with torsion  

E-print Network

We study Dirac-harmonic maps from surfaces to manifolds with torsion, which is motivated from the superstring action considered in theoretical physics. We discuss analytic and geometric properties of such maps and outline an existence result for uncoupled solutions.

Volker Branding

2014-05-20

212

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

213

A UNIFIED ANALYSIS OF TRANSMISSION CONDITIONS FOR THIN CONDUCTING SHEETS IN THE TIME-HARMONIC EDDY CURRENT MODEL  

E-print Network

-harmonic eddy current model in two dimensions. The first criterion is the robustness with respect Expansions, Eddy- current model AMS subject classifications. 65N30, 35C20, 35J25, 41A60, 35B40, 78M30, 78M35 Introduction. For simulations of the eddy current problem with thin sheets by standard methods, like the finite

Nabben, Reinhard

214

High-Speed Video Analysis in a Conceptual Physics Class  

ERIC Educational Resources Information Center

The use of probe ware and computers has become quite common in introductory physics classrooms. Video analysis is also becoming more popular and is available to a wide range of students through commercially available and/or free software. Video analysis allows for the study of motions that cannot be easily measured in the traditional lab setting…

Desbien, Dwain M.

2011-01-01

215

Gender and Physics: A Theoretical Analysis.  

ERIC Educational Resources Information Center

Argues that objections raised by Koertge, Gross and Levitt, and Weinberg against feminist scholarship are unwarranted. The concept of gender, as it has been developed in feminist theory, is key to understanding why the first objection is misguided. Social analysis of scientific knowledge is key to understanding why the second and third objections…

Rolin, Kristina

2001-01-01

216

Analysis of ANS LWR physics benchmark problems.  

SciTech Connect

Various Monte Carlo and deterministic solutions to the three PWR Lattice Benchmark Problems recently defined by the ANS Ad Hoc Committee on Reactor Physics Benchmarks are presented. These solutions were obtained using the VIM continuous-energy Monte Carlo code and the DIF3D/WIMS-D4M code package implemented at the Argonne National Laboratory. The code results for the K{sub eff} and relative pin power distribution are compared to measured values. Additionally, code results for the three benchmark-prescribed infinite lattice configurations are also intercompared. The results demonstrate that the codes produce very good estimates of both the K{sub eff} and power distribution for the critical core and the lattice parameters of the infinite lattice configuration.

Taiwo, T. A.

1998-07-29

217

Absolute Single-Molecule Entropies from Quasi-Harmonic Analysis of Microsecond Molecular Dynamics: Correction Terms and Convergence Properties  

PubMed Central

The convergence properties of the absolute single-molecule configurational entropy and the correction terms used to estimate it are investigated using microsecond molecular dynamics simulation of a peptide test system and an improved methodology. The results are compared with previous applications for systems of diverse chemical nature. It is shown that (i) the effect of anharmonicity is small, (ii) the effect of pairwise correlation is typically large, and (iii) the latter affects to a larger extent the entropy estimate of thermodynamic states characterized by a higher motional correlation. The causes of such deviations from a quasi-harmonic behavior are explained. This improved approach provides entropies also for molecular systems undergoing conformational transitions and characterized by highly frustrated energy surfaces, thus not limited to systems sampling a single quasi-harmonic basin. Overall, this study emphasizes the need for extensive phase-space sampling in order to obtain a reliable estimation of entropic contributions. PMID:20011626

2009-01-01

218

HEPDOOP: High-Energy Physics Analysis using Hadoop  

NASA Astrophysics Data System (ADS)

We perform a LHC data analysis workflow using tools and data formats that are commonly used in the "Big Data" community outside High Energy Physics (HEP). These include Apache Avro for serialisation to binary files, Pig and Hadoop for mass data processing and Python Scikit-Learn for multi-variate analysis. Comparison is made with the same analysis performed with current HEP tools in ROOT.

Bhimji, W.; Bristow, T.; Washbrook, A.

2014-06-01

219

Plasma physics analysis of SERT-2 operation  

NASA Technical Reports Server (NTRS)

An analysis of the major plasma processes involved in the SERT 2 spacecraft experiments was conducted to aid in the interpretation of recent data. A plume penetration model was developed for neutralization electron conduction to the ion beam and showed qualitative agreement with flight data. In the SERT 2 configuration conduction of neutralization electrons between thrusters was experimentally demonstrated in space. The analysis of this configuration suggests that the relative orientation of the two magnetic fields was an important factor in the observed results. Specifically, the opposed field orientation appeared to provide a high conductivity channel between thrusters and a barrier to the ambient low energy electrons in space. The SERT 2 neutralizer currents with negative neutralizer biases were up to about twice the theoretical prediction for electron collection by the ground screen. An explanation for the higher experimental values was a possible conductive path from the neutralizer plume to a nearby part of the ground screen. Plasma probe measurements of SERT 2 gave the clearest indication of plasma electron temperature, with normal operation being near 5 eV and discharge only operation near 2 eV.

Kaufman, H. R.

1980-01-01

220

Extraction of small boat harmonic signatures from passive sonar.  

PubMed

This paper investigates the extraction of acoustic signatures from small boats using a passive sonar system. Noise radiated from a small boats consists of broadband noise and harmonically related tones that correspond to engine and propeller specifications. A signal processing method to automatically extract the harmonic structure of noise radiated from small boats is developed. The Harmonic Extraction and Analysis Tool (HEAT) estimates the instantaneous fundamental frequency of the harmonic tones, refines the fundamental frequency estimate using a Kalman filter, and automatically extracts the amplitudes of the harmonic tonals to generate a harmonic signature for the boat. Results are presented that show the HEAT algorithms ability to extract these signatures. PMID:21682400

Ogden, George L; Zurk, Lisa M; Jones, Mark E; Peterson, Mary E

2011-06-01

221

Non-linear dynamic analysis of a multi-mesh gear train using multi-term harmonic balance method: period-one motions  

NASA Astrophysics Data System (ADS)

A non-linear time-varying dynamic model of a typical multi-mesh gear train is proposed in this study. The physical system includes three rigid shafts coupled by two gear pairs. The lumped parameter dynamic model includes the gear backlash in the form of clearance-type displacement functions and parametric variation of gear mesh stiffness values dictated by the gear contact ratios. The system is reduced to a two-degree-of-freedom definite model by using the relative gear mesh displacements as the coordinates. Dimensionless equations of motion are solved for the steady-state period-1 response by using a multi-term Harmonic Balance Method (HBM) in conjunction with discrete Fourier Transforms and a Parametric Continuation scheme. The accuracy of the HBM solutions is demonstrated by comparing them to direct numerical integration solutions. Floquet theory is applied to determine the stability of the steady-state harmonic balance solutions. An example gear train is used to investigate the influence of key system parameters including alternating mesh stiffness amplitudes, gear mesh damping, static torque transmitted, and the gear mesh frequency ratio.

Al-shyyab, A.; Kahraman, A.

2005-06-01

222

Combining Computational Physics with Video Analysis in Tracker  

NSDL National Science Digital Library

In Spring 2007, introductory mechanics students at Cabrillo College used Tracker to compare 2D particle models with videos of real-world motion. After doing a traditional motion video analysis lab, students used both analytic (position functions) and dynamic (force functions and initial conditions for numerical solvers) models to draw overlays directly on their captured videos. The video thus provided a "reality check" while students explored different models, parameters and algorithms. In addition to the visual overlays, the models generated "experimental data" for graphing and analysis just like experimental (student-marked) tracks. This paper will describe my own and my students' experiences with this first exposure to computational physics in the curriculum. Tracker is a JAVA video/image analysis tool developed by the Open Source Physics Project. The Open Source Physics project is supported in part by the National Science Foundation grants DUE-0126439 and DUE-0442481.

Brown, Douglas

2010-10-14

223

The harmonic mean field model for molecular solvents: A liquid state analog of the harmonic oscillator-rigid top approximation  

NASA Astrophysics Data System (ADS)

A liquid state analog of the gas phase harmonic oscillator-rigid top model is developed. This analog, which we call the harmonic mean field model, permits one to compute the equilibrium and dynamic properties of real, i.e., vibrating, molecular solvents from the structure and dynamics of the corresponding rigid solvents. The harmonic mean field model is based on: (i) A mean field harmonic model for the solvent vibrational (V) force field. (ii) A rigid solvent model treatment of translational-rotational (TR) fluctuations. (iii) Complete neglect of explicit coupling between V and TR fluctuations. (Implicit coupling is included in the vibrational force field.) The model is developed for statics via a sequence of physically motivated approximations to the exact canonical ensemble phase space distribution function of the solvent, fCA[S]. This yields a model distribution function f(0)CA[S] =f(0)CA[pyy]fCA[pww; v0], where f(0)CA[pyy] is an effective harmonic vibrational phase space distribution function which describes mean field harmonic V fluctuations and where f(0)CA[pww; v0] is the rigid solvent canonical ensemble distribution function. The nonequilibrium version of the model is defined as the solvent dynamics generated by a model Liouville operator L(0). This is defined via the model equilibrium Liouville equation L(0)f(0)CA [S]=0. Explicit results for equilibrium averages and time correlation functions of molecular solvents are obtained. The frequency spectra of the time correlation functions contain a low frequency ``acoustic'' branch arising from solvent TR motions and high frequency ``optical'' branches arising from collective solvent V motions. A detailed analysis of the frequency spectra of autocorrelation functions of diatomic solvents is presented.

Adelman, Steven A.; Balk, Michael W.

1985-05-01

224

Simple Harmonic Motion in Harmonic Plane Waves.  

ERIC Educational Resources Information Center

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)

Benumof, Reuben

1980-01-01

225

Harmonic nanoparticles for regenerative research.  

PubMed

In this visualized experiment, protocol details are provided for in vitro labeling of human embryonic stem cells (hESC) with second harmonic generation nanoparticles (HNPs). The latter are a new family of probes recently introduced for labeling biological samples for multi-photon imaging. HNPs are capable of doubling the frequency of excitation light by the nonlinear optical process of second harmonic generation with no restriction on the excitation wavelength. Multi-photon based methodologies for hESC differentiation into cardiac clusters (maintained as long term air-liquid cultures) are presented in detail. In particular, evidence on how to maximize the intense second harmonic (SH) emission of isolated HNPs during 3D monitoring of beating cardiac tissue in 3D is shown. The analysis of the resulting images to retrieve 3D displacement patterns is also detailed. PMID:24836220

Ronzoni, Flavio; Magouroux, Thibaud; Vernet, Remi; Extermann, Jérôme; Crotty, Darragh; Prina-Mello, Adriele; Ciepielewski, Daniel; Volkov, Yuri; Bonacina, Luigi; Wolf, Jean-Pierre; Jaconi, Marisa

2014-01-01

226

Spectral Analysis of Vibrational Harmonic Motion by use of a Continuous-Wave CO2 Doppler Lidar  

NASA Technical Reports Server (NTRS)

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.

Jarzembski, Maurice A.; Srivastava, Vandana

1999-01-01

227

Temporal and spatial variability of tidal-fluvial dynamics in the St. Lawrence fluvial estuary: An application of nonstationary tidal harmonic analysis  

NASA Astrophysics Data System (ADS)

tides in upstream reaches of rivers is a challenge, because tides are highly nonlinear and nonstationary, and accurate short-time predictions of river flow are hard to obtain. In the St. Lawrence fluvial estuary, tide forecasts are produced using a one-dimensional model (ONE-D), forced downstream with harmonic constituents, and upstream with daily discharges using 30 day flow forecasts from Lake Ontario and the Ottawa River. Although this operational forecast system serves its purpose of predicting water levels, information about nonstationary tidal-fluvial processes that can be gained from it is limited, particularly the temporal changes in mean water level and tidal properties (i.e., constituent amplitudes and phases), which are function of river flow and ocean tidal range. In this paper, a harmonic model adapted to nonstationary tides, NS_TIDE, was applied to the St. Lawrence fluvial estuary, where the time-varying external forcing is directly built into the tidal basis functions. Model coefficients from 13 analysis stations were spatially interpolated to allow tide predictions at arbitrary locations as well as to provide insights into the spatiotemporal evolution of tides. Model hindcasts showed substantial improvements compared to classical harmonic analyses at upstream stations. The model was further validated by comparison with ONE-D predictions at a total of 32 stations. The slightly lower accuracy obtained with NS_TIDE is compensated by model simplicity, efficiency, and capacity to represent stage and tidal variations in a very compact way and thus represents a new means for understanding tidal rivers.

Matte, Pascal; Secretan, Yves; Morin, Jean

2014-09-01

228

Polynomial Harmonic Morphisms Martin Svensson  

E-print Network

Polynomial Harmonic Morphisms Martin Svensson Examensarbete, 20 poang Lunds Universitet November Chapter 2. Harmonic Maps 13 1. The Second Fundamental Form 13 2. Harmonic Maps 18 3. Harmonic Functions 25 Chapter 3. Harmonic Morphisms 29 1. Horizontal Conformality 29 2. Harmonic Morphisms 33 3. The Existence

Gudmundsson, Sigmundur

229

Physics-based deformable organisms for medical image analysis  

NASA Astrophysics Data System (ADS)

Previously, "Deformable organisms" were introduced as a novel paradigm for medical image analysis that uses artificial life modelling concepts. Deformable organisms were designed to complement the classical bottom-up deformable models methodologies (geometrical and physical layers), with top-down intelligent deformation control mechanisms (behavioral and cognitive layers). However, a true physical layer was absent and in order to complete medical image segmentation tasks, deformable organisms relied on pure geometry-based shape deformations guided by sensory data, prior structural knowledge, and expert-generated schedules of behaviors. In this paper we introduce the use of physics-based shape deformations within the deformable organisms framework yielding additional robustness by allowing intuitive real-time user guidance and interaction when necessary. We present the results of applying our physics-based deformable organisms, with an underlying dynamic spring-mass mesh model, to segmenting and labelling the corpus callosum in 2D midsagittal magnetic resonance images.

Hamarneh, Ghassan; McIntosh, Chris

2005-04-01

230

Physical optics analysis of a beam waveguide with six reflectors  

Microsoft Academic Search

An efficient code for the analysis of beam waveguides and multireflector antennas by PO (physical optics) integration is presented. In the ELAB PO-code, there is no restriction on the number of reflectors, each reflector can be numerically specified to any shape, and the reflectors may be plane or parts of ellipsoids, with elliptical contours. The code has been applied to

P.-S. Kildal; Jacob Kuhnle; Kees van t'Klooster; Robert Graham

1990-01-01

231

Towards PCB physical design automation: architectural analysis and synthesis  

Microsoft Academic Search

The use of architectural definition tools to ensure the validity of early designs is crucial to avoid costly rework of the product architecture by catching potential design errors before starting detailed physical realization. Design automation tools with analysis and synthesis capabilities at both component and board levels can be the key to the design of today's complex systems with shrinking

Delfin Y. Montuno; Q. J. Zhang; B. Stacey; Wenfeng Chen; V. Chaudhary; D. Poirier; T. Mentor

1997-01-01

232

Web Assignments: Harmonic Oscillator I  

NSDL National Science Digital Library

This student activity uses a Java applet to show the relationship between simple harmonic motion and constant velocity circular motion. The applet is broken into three major parts. The first shows a particle undergoing circular motion at a constant rate. The second shows the same particle on a vertical spring. Finally, the third plots the time evolution of the system, resulting in a sine wave. Instructions for using the applet, which is in Spanish, are included. The applet includes several questions relating to the applet and the physics of harmonic motion. This is part of a larger collection of applet-based learning activities.This student activity uses a Java applet to show the relationship between simple harmonic motion and constant circular motion. The applet is broken into three major parts. The first shows a particle undergoing circular motion at a constant rate. The second shows the same particle on a vertical spring. Finally, the third plots the time evolution of the system -- the result is a sine wave. The amplitude, frequency, and initial phase of the harmonic motion can be changed by typing in new values in the "Amplitud", "Frequencia", and "Fase Inicial" text windows, respectively. To start the applet, press the "Empiaza" button. To pause the motion, press "Pausa," and to stop the applet press "Paso." The user is asked to answer several questions relating to the applet. This is part of a larger collection of applet-based learning activities.

Walkup, John

2008-11-23

233

Data management, archiving, visualization and analysis of space physics data  

NASA Technical Reports Server (NTRS)

A series of programs for the visualization and analysis of space physics data has been developed at UCLA. In the course of those developments, a number of lessons have been learned regarding data management and data archiving, as well as data analysis. The issues now facing those wishing to develop such software, as well as the lessons learned, are reviewed. Modern media have eased many of the earlier problems of the physical volume required to store data, the speed of access, and the permanence of the records. However, the ultimate longevity of these media is still a question of debate. Finally, while software development has become easier, cost is still a limiting factor in developing visualization and analysis software.

Russell, C. T.

1995-01-01

234

Game theoretic analysis of physical protection system design  

SciTech Connect

The physical protection system (PPS) of a fictional small modular reactor (SMR) facility have been modeled as a platform for a game theoretic approach to security decision analysis. To demonstrate the game theoretic approach, a rational adversary with complete knowledge of the facility has been modeled attempting a sabotage attack. The adversary adjusts his decisions in response to investments made by the defender to enhance the security measures. This can lead to a conservative physical protection system design. Since defender upgrades were limited by a budget, cost benefit analysis may be conducted upon security upgrades. One approach to cost benefit analysis is the efficient frontier, which depicts the reduction in expected consequence per incremental increase in the security budget.

Canion, B.; Schneider, E. [Nuclear and Radiation Engineering Program, University of Texas, 204 E. Dean Keeton Street, Stop C2200, Austin, TX 78712 (United States); Bickel, E.; Hadlock, C.; Morton, D. [Operations Research Program, University of Texas, 204 E. Dean Keeton Street, Stop C2200, Austin, TX 78712 (United States)

2013-07-01

235

RMC - A Monte Carlo code for reactor physics analysis  

SciTech Connect

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)

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

236

High order harmonic generation in rare gases  

SciTech Connect

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.

Budil, K.S.

1994-05-01

237

Transient regime in second harmonic generation  

NASA Astrophysics Data System (ADS)

The time growth of the electromagnetic field at the fundamental and double frequencies is studied from the very onset of the second harmonic generation (SHG) process for a set of dipoles lacking a symmetry centre and exhibiting a nonresonant coupling with a classical electromagnetic field. This approach consists first of solving the Schrödinger equation by applying a generalised Rabi rotation to the Hamiltonian describing the light-dipole interaction. This rotation has been devised for the resulting Hamiltonian to show up time-independent for both components of the electromagnetic field at the fundamental frequency and the second harmonic one. Then an energy conservation argument, derived from the Poynting theorem, is introduced to work out an additional relationship between the electromagnetic field and its associated electric polarisation. Finally this analysis yields the full time behaviour of all physical quantities of interest. The calculated results reproduce accurately both the observed spatial oscillations of the SHG intensity (Maker's fringes) and its power law dependence on the intensity of the incoming light at the fundamental frequency.

Szeftel, Jacob; Sandeau, Laure; Sandeau, Nicolas; Delezoide, Camille; Khater, Antoine

2013-09-01

238

A novel method of data analysis for hadronic physics  

E-print Network

A novel method for extracting physical parameters from experimental and simulation data is presented. The method is based on statistical concepts and it relies on Monte Carlo simulation techniques. It identifies and determines with maximal precision parameters that are sensitive to the data. The method has been extensively studied and it is shown to produce unbiased results. It is applicable to a wide range of scientific and engineering problems. It has been successfully applied in the analysis of experimental data in hadronic physics and of lattice QCD correlators.

C. N. Papanicolas; E. Stiliaris

2012-05-29

239

Vibration analysis of cracked rotor sliding bearing system with rotor-stator rubbing by harmonic wavelet transform  

NASA Astrophysics Data System (ADS)

In this paper, the vibration of a cracked rotor sliding bearing system with rotor-stator rubbing is investigated using harmonic wavelet transform (HWT). Three non-linear factors, non-linear oil film forces, rotor-stator rubbing and the presence of crack, are taken into account. So the non-linear behavior of the rotor will be much more complex. According to Newmark method, the dynamic response of the rotor is calculated. Using HWT method, the effect of these non-linear factors is analyzed simultaneously in both time and frequency domain. The numerical simulated result shows that HWT will be available to analyze this multi-non-linear factors rotor effectively and can reveal the exact fault characteristics in detail.

Wan, Fangyi; Xu, Qingyu; Li, Songtao

2004-04-01

240

Dynamic analysis of composite beam subjected to harmonic moving load based on the third-order shear deformation theory  

NASA Astrophysics Data System (ADS)

The response of an infinite Timoshenko beam subjected to a harmonic moving load based on the thirdorder shear deformation theory (TSDT) is studied. The beam is made of laminated composite, and located on a Pasternak viscoelastic foundation. By using the principle of total minimum potential energy, the governing partial differential equations of motion are obtained. The solution is directed to compute the deflection and bending moment distribution along the length of the beam. Also, the effects of two types of composite materials, stiffness and shear layer viscosity coefficients of foundation, velocity and frequency of the moving load over the beam response are studied. In order to demonstrate the accuracy of the present method, the results TSDT are compared with the previously obtained results based on first-order shear deformation theory, with which good agreements are observed.

Rezvanil, Mohammad Javad; Kargarnovin, Mohammad Hossein; Younesian, Davood

2011-12-01

241

Harmonic Analysis of Time Variations Observed in the Solar Radio Flux Measured at 810 MHz from 1957 to 2004  

E-print Network

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.

S. Zieba; J. Maslowski; A. Michalec; G. Michalek; A. Kulak

2007-01-15

242

Synchronous Discrete Harmonic Oscillator  

SciTech Connect

We introduce the synchronous discrete harmonic oscillator, and present an analytical, numerical and graphical study of its characteristics. The oscillator is synchronous when the time T for one revolution covering an angle of 2{pi} in phase space, is an integral multiple N of the discrete time step {delta}t. It is fully synchronous when N is even. It is pseudo-synchronous when T/{delta}t is rational. In the energy conserving hyperincursive representation, the phase space trajectories are perfectly stable at all time scales, and in both synchronous and pseudo-synchronous modes they cycle through a finite number of phase space points. Consequently, both the synchronous and the pseudo-synchronous hyperincursive modes of time-discretization provide a physically realistic and mathematically coherent, procedure for dynamic, background independent, discretization of spacetime. The procedure is applicable to any stable periodic dynamical system, and provokes an intrinsic correlation between space and time, whereby space-discretization is a direct consequence of background-independent time-discretization. Hence, synchronous discretization moves the formalism of classical mechanics towards that of special relativity. The frequency of the hyperincursive discrete harmonic oscillator is ''blue shifted'' relative to its continuum counterpart. The frequency shift has the precise value needed to make the speed of the system point in phase space independent of the discretizing time interval {delta}t. That is the speed of the system point is the same on the polygonal (in the discrete case) and the circular (in the continuum case) phase space trajectories.

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)

2008-10-17

243

A Global Sensitivity Analysis Methodology for Multi-physics Applications  

SciTech Connect

Experiments are conducted to draw inferences about an entire ensemble based on a selected number of observations. This applies to both physical experiments as well as computer experiments, the latter of which are performed by running the simulation models at different input configurations and analyzing the output responses. Computer experiments are instrumental in enabling model analyses such as uncertainty quantification and sensitivity analysis. This report focuses on a global sensitivity analysis methodology that relies on a divide-and-conquer strategy and uses intelligent computer experiments. The objective is to assess qualitatively and/or quantitatively how the variabilities of simulation output responses can be accounted for by input variabilities. We address global sensitivity analysis in three aspects: methodology, sampling/analysis strategies, and an implementation framework. The methodology consists of three major steps: (1) construct credible input ranges; (2) perform a parameter screening study; and (3) perform a quantitative sensitivity analysis on a reduced set of parameters. Once identified, research effort should be directed to the most sensitive parameters to reduce their uncertainty bounds. This process is repeated with tightened uncertainty bounds for the sensitive parameters until the output uncertainties become acceptable. To accommodate the needs of multi-physics application, this methodology should be recursively applied to individual physics modules. The methodology is also distinguished by an efficient technique for computing parameter interactions. Details for each step will be given using simple examples. Numerical results on large scale multi-physics applications will be available in another report. Computational techniques targeted for this methodology have been implemented in a software package called PSUADE.

Tong, C H; Graziani, F R

2007-02-02

244

Reactor Physics Methods and Analysis Capabilities in SCALE  

SciTech Connect

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.

DeHart, Mark D [ORNL; Bowman, Stephen M [ORNL

2011-01-01

245

Reactor Physics Methods and Analysis Capabilities in SCALE  

SciTech Connect

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.

Mark D. DeHart; Stephen M. Bowman

2011-05-01

246

Physically based groundwater vulnerability assessment using sensitivity analysis methods.  

PubMed

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

Beaujean, Jean; Lemieux, Jean-Michel; Dassargues, Alain; Therrien, René; Brouyère, Serge

2014-01-01

247

Geomagnetic local and regional harmonic analyses.  

USGS Publications Warehouse

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

Alldredge, L.R.

1982-01-01

248

Tabletop coherent extreme ultraviolet and soft X-ray sources based on high harmonic generation  

E-print Network

High harmonic generation (HHG) is a fascinating strong-field physics phenomenon that occurs when a laser pulse with a moderate intensity interacts with atoms and partially ionizes the atoms. A series of harmonics are ...

Lai, Chien-Jen, Ph. D. Massachusetts Institute of Technology

2014-01-01

249

When is the product of two planar harmonic mappings harmonic?  

E-print Network

When is the product of two planar harmonic mappings harmonic? Raymond Mortini Lecturas Matem´aticas Volumen 23 (2002), p´aginas 5­10 Abstract. We determine all complex-valued harmonic functions u and v defined on a planar domain for which uv, respectively u2 - v2 is harmonic Key words and phrases. Harmonic

Mortini, Raymond

250

QA/QC requirements for physical properties sampling and analysis  

SciTech Connect

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.

Innis, B.E.

1993-07-21

251

Physically And Statistically Based Deformable Models For Medical Image Analysis  

Microsoft Academic Search

Medical imaging continues to permeate the practice of medicine, but automated yet accurate segmentation and labeling of anatomical\\u000a structures continues to be a major obstacle to computerized medical image analysis. Deformable models, with their roots in\\u000a estimation theory, optimization, and physics-based dynamical systems, represent a powerful approach to the general problem\\u000a of medical image segmentation. This chapter presents an introduction

Ghassan Hamarneh; Chris McIntosh

252

Compositional schedulability analysis for cyber-physical systems  

Microsoft Academic Search

Cyber-physical systems (CPSs) are becoming all-pervasive, and due to increasing complexity they are designed using component-based approaches. Temporal constraints of such complex CPSs are then modeled using hierarchical scheduling frameworks. Therefore, there is a need to develop compositional schedulability analysis techniques for such CPSs. In this essay, we describe one such CPS present in air-crafts. We also discuss the hierarchical

Arvind Easwaran; Insup Lee

2008-01-01

253

Preliminary Safety Analysis Report for the Tokamak Physics Experiment  

SciTech Connect

This Preliminary Safety Analysis Report (PSAR), includes an indication of the magnitude of facility hazards, complexity of facility operations, and the stage of the facility life-cycle. It presents the results of safety analyses, safety assurance programs, identified vulnerabilities, compensatory measures, and, in general, the rationale describing why the Tokamak Physics Experiment (TPX) can be safely operated. It discusses application of the graded approach to the TPX safety analysis, including the basis for using Department of Energy (DOE) Order 5480.23 and DOE-STD-3009-94 in the development of the PSAR.

Motloch, C.G.; Bonney, R.F. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Levine, J.D. [Princeton Univ., NJ (United States). Plasma Physics Lab.; McKenzie-Carter, M.A. [Science Applications International Corp., San Diego, CA (United States); Masson, L.S. [SCIENTECH, Inc., Idaho Falls, ID (United States); Commander, J.C.

1995-04-01

254

Active Harmonic Filters  

Microsoft Academic Search

Unlike traditional passive harmonic filters, modern active harmonic filters have the following multiple functions: harmonic filtering, damping,isolation and termination, reactive-power control for power factor correction and voltage regulation, load balancing, voltage-flicker reduction, and\\/or their combinations. Significant cost reductions in both power semiconductor devices and signal processing devices have inspired manufactures to put active filters on the market. This paper deals

HIROFUMI AKAGI

2005-01-01

255

Performance for passive and active power filter in reducing harmonics in the distribution system  

Microsoft Academic Search

This paper presents the results for the performance of passive and active power filter to reduce harmonics in the distribution system. The harmonics analysis is performed in order to observe the percentage reduction of amplitude current harmonics and total harmonic distortion for passive and active power filter at various loads. In addition to that the bidirectional switching is used as

M. Izhar; C. M. Hadzer; M. Syafrudin; S. Taib; S. Idris

2004-01-01

256

Harmonic Content of Strain-induced Potential Modulation in Unidirectional Lateral Superlattices  

E-print Network

Harmonic Content of Strain-induced Potential Modulation in Unidirectional Lateral Superlattices from a ¼ 92 to 184 nm. Fourier analysis reveals the second (and the third) harmonics along of corresponding harmonics in the profile of the potential modulation. The harmonics manifest themselves in CO

Katsumoto, Shingo

257

Even harmonic lasing  

SciTech Connect

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.

Schmitt, M.J.

1991-01-01

258

Detailed analysis of second-harmonic generation near 10.6 microns in GaAs\\/AlGaAs asymmetric quantum wells  

Microsoft Academic Search

The paper reports on the observation of resonant intersubband second-harmonic generation in asymmetric GaAs\\/AlGaAs quantum wells using a CW or Q-switched tunable CO2 laser as the pumping source. The dependence of the second-harmonic intensity on the pump photon wavelength is presented for the first time. A Lorentzian-like second-harmonic line shape is found with a maximum at 10.9 microns and a

P. Boucaud; F. H. Julien; D. D. Yang; J.-M. Lourtioz; E. Rosencher; P. Bois; J. Nagle

1990-01-01

259

HARMONIC AMPLIFIER FREE ELECTRON LASER  

Microsoft Academic Search

The harmonic optical klystron (HOK) in which the second undulator is resonant on the higher harmonic of the first undulator is analysed as a harmonic amplifier. The optical field evolution equation of the HOK is derived analytically for both CHG mode (Coherent Harmonic Generation, the quadratic gain regime) and HGHG mode (High Gain Harmonic Generation, the exponential gain regime), the

Jia Qika

260

Signature of a non-harmonic potential as revealed from a consistent shape and fluctuation analysis of an adherent membrane  

E-print Network

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.

Daniel Schmidt; Cornelia Monzel; Timo Bihr; Rudolf Merkel; Udo Seifert; Kheya Sengupta; Ana-Sun?ana Smith

2014-03-28

261

New breathing functions for the transverse breathing crack of the cracked rotor system: Approach for critical and subcritical harmonic analysis  

NASA Astrophysics Data System (ADS)

The actual breathing mechanism of the transverse breathing crack in the cracked rotor system that appears due to the shaft weight is addressed here. As a result, the correct time-varying area moments of inertia for the cracked element cross-section during shaft rotation are also determined. Hence, two new breathing functions are identified to represent the actual breathing effect on the cracked element stiffness matrix. The new breathing functions are used in formulating the time-varying finite element stiffness matrix of the cracked element. The finite element equations of motion are then formulated for the cracked rotor system and solved via harmonic balance method for response, whirl orbits and the shift in the critical and subcritical speeds. The analytical results of this approach are compared with some previously published results obtained using approximate formulas for the breathing mechanism. The comparison shows that the previously used breathing function is a weak model for the breathing mechanism in the cracked rotor even for small crack depths. The new breathing functions give more accurate results for the dynamic behavior of the cracked rotor system for a wide range of the crack depths. The current approach is found to be efficient for crack detection since the critical and subcritical shaft speeds, the unique vibration signature in the neighborhood of the subcritical speeds and the sensitivity to the unbalance force direction all together can be utilized to detect the breathing crack before further damage occurs.

Al-Shudeifat, Mohammad A.; Butcher, Eric A.

2011-01-01

262

Analysis of the electrical harmonic characteristics of a slip recovery variable speed generating system for wind turbine applications  

NASA Astrophysics Data System (ADS)

Variable speed electric generating technology can enhance the general use of wind energy in electric utility applications. This enhancement results from two characteristic properties of variable speed wind turbine generators: an improvement in drive train damping characteristics, which results in reduced structural loading on the entire wind turbine system, and an improvement in the overall efficiency by using a more sophisticated electrical generator. Electronic converter systems are the focus of this investigation -- in particular, the properties of a wound-rotor induction generator with the slip recovery system and direct-current link converter. Experience with solid-state converter systems in large wind turbines is extremely limited. This report presents measurements of electrical performances of the slip recovery system and is limited to the terminal characteristics of the system. Variable speed generating systems working effectively in utility applications will require a satisfactory interface between the turbine/generator pair and the utility network. The electrical testing described herein focuses largely on the interface characteristics of the generating system. A MOD-O wind turbine was connected to a very strong system; thus, the voltage distortion was low and the total harmonic distortion in the utility voltage was less than 3 percent (within the 5 percent limit required by most utilities). The largest voltage component of a frequency below 60 Hz was 40 dB down from the 60-Hz less than component.

Herrera, J. I.; Reddoch, T. W.

1988-02-01

263

Hyperspherical harmonic formalism for tetraquarks  

E-print Network

We present a generalization of the hyperspherical harmonic formalism to study systems made of quarks and antiquarks of the same flavor. This generalization is based on the symmetrization of the $N-$body wave function with respect to the symmetric group using the Barnea and Novoselsky algorithm. Our analysis shows that four-quark systems with non-exotic $2^{++}$ quantum numbers may be bound independently of the quark mass. $0^{+-}$ and $1^{+-}$ states become attractive only for larger quarks masses.

J. Vijande; N. Barnea; A. Valcarce

2006-10-11

264

Symbolic Vector Analysis in Plasma Physics H. Qin, W. M. Tang, and G. Rewoldt  

E-print Network

Symbolic Vector Analysis in Plasma Physics H. Qin, W. M. Tang, and G. Rewoldt Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ, 08543­451 Many problems in plasma physics involve to their problems. Several applications of this symbolic vector analysis package to plasma physics are also given

265

Harmonizing Civil Engineering Education  

Microsoft Academic Search

Uniformity never will be the objective of education, yet some level of compatibility can be useful or even indi spensable. Though academic teachers are rather attached to the idea of University autonomy and freedom than to any form of harmonization, some harmonization is necessary to assure readable and comparable professional degrees, as well as comparable criteria of quality assurance, irrespective

Stanisøaw Majewski

266

Electrodynamic spherical harmonic  

E-print Network

Electrodynamic spherical harmonic is a second rank tensor in three-dimensional space. It allows to separate the radial and angle variables in vector solutions of Maxwell's equations. Using the orthonormalization for electrodynamic spherical harmonic, a boundary problem on a sphere can be easily solved.

Andrey Novitsky

2008-03-28

267

Relativistic harmonic oscillator revisited  

SciTech Connect

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.

Bars, Itzhak [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-2535 (United States)

2009-02-15

268

Molecular structure, normal coordinate analysis, harmonic vibrational frequencies, NBO, HOMO-LUMO analysis and detonation properties of (S)-2-(2-oxopyrrolidin-1-yl) butanamide by density functional methods  

NASA Astrophysics Data System (ADS)

Density functional theory (DFT) computations have become an efficient tool in the prediction of molecular structure, harmonic force fields, vibrational wave numbers as well as the IR and Raman intensities of pharmaceutically important molecule. In this work, we report harmonic vibrational frequencies, molecular structure, NBO and HOMO, LUMO analysis and detonation properties of (S)-2-(2-oxopyrrolidin-1-yl) butanamide. The solid phase FT-IR and FT-Raman spectra of (S)-2-(2-oxopyrrolidin-1-yl) butanamide were recorded in the region 4000-450 cm-1 and 4000-50 cm-1 respectively. Harmonic frequencies of this compound were determined and analyzed by DFT utilizing 6-31G(d,p), 6-31+G(d,p) basis sets. 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 calculated infrared and Raman spectra of the title compounds were also stimulated utilizing the scaled force fields and the computed dipole derivatives for IR intensities and polarizability derivatives for Raman intensities. The change in electron density (ED) in the ?* and ?* antibonding orbital's 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. Heat of formation (HOF) and calculated density were estimated to evaluate detonation properties using Kamlet-Jacobs equations. The linear polarizability (?) and the first order hyperpolarizability (?) values of the investigated molecule have been computed using DFT calculations. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The observed and calculated wave numbers are found to be in good agreement. On the basis of vibrational analyses, the thermodynamic properties of title compound at different temperatures have been calculated.

Renuga, S.; Muthu, S.

2014-01-01

269

Positioning Ideas: Creating and Relating Physics Identities Through Video Analysis  

NASA Astrophysics Data System (ADS)

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.

Harlow, Danielle Boyd; Swanson, Lauren H.

2009-11-01

270

Toward the automated analysis of plasma physics problems  

SciTech Connect

A program (CALC) is described, which carries out nontrivial plasma physics calculations, in a manner intended to emulate the approach of a human theorist. This includes the initial process of gathering the relevant equations from a plasma knowledge base, and then determining how to solve them. Solution of the sets of equations governing physics problems, which in general have a nonuniform,irregular structure, not amenable to solution by standardized algorithmic procedures, is facilitated by an analysis of the structure of the equations and the relations among them. This often permits decompositions of the full problem into subproblems, and other simplifications in form, which renders the resultant subsystems soluble by more standardized tools. CALC's operation is illustrated by a detailed description of its treatment of a sample plasma calculation. 5 refs., 3 figs.

Mynick, H.E.

1989-04-01

271

Introduction to the Space Physics Analysis Network (SPAN)  

NASA Technical Reports Server (NTRS)

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.

Green, J. L. (editor); Peters, D. J. (editor)

1985-01-01

272

Multi-Physics Analysis of the Fermilab Booster RF Cavity  

SciTech Connect

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.

Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.; /Fermilab

2012-05-14

273

Determining physical constraints in transcriptional initiationcomplexes using DNA sequence analysis  

SciTech Connect

Eukaryotic gene expression is often under the control ofcooperatively acting transcription factors whose binding is limited bystructural constraints. By determining these structural constraints, wecan understand the "rules" that define functional cooperativity.Conversely, by understanding the rules of binding, we can inferstructural characteristics. We have developed an information theory basedmethod for approximating the physical limitations of cooperativeinteractions by comparing sequence analysis to microarray expressiondata. When applied to the coordinated binding of the sulfur amino acidregulatory protein Met4 by Cbf1 and Met31, we were able to create acombinatorial model that can correctly identify Met4 regulatedgenes.

Shultzaberger, Ryan K.; Chiang, Derek Y.; Moses, Alan M.; Eisen,Michael B.

2007-07-01

274

The Local Stellar Velocity Field via Vector Spherical Harmonics  

NASA Technical Reports Server (NTRS)

We analyze the local field of stellar tangential velocities for a sample of 42,339 nonbinary Hipparcos stars with accurate parallaxes, using a vector spherical harmonic formalism. We derive simple relations between the parameters of the classical linear model (Ogorodnikov-Milne) of the local systemic field and low-degree terms of the general vector harmonic decomposition. Taking advantage of these relationships, we determine the solar velocity with respect to the local stars of (V(sub X), V(sub Y), V(sub Z)) (10.5, 18.5, 7.3) +/- 0.1 km s(exp -1) not corrected for the asymmetric drift with respect to the local standard of rest. If only stars more distant than 100 pc are considered, the peculiar solar motion is (V(sub X), V(sub Y), V(sub Z)) (9.9, 15.6, 6.9) +/- 0.2 km s(exp -1). The adverse effects of harmonic leakage, which occurs between the reflex solar motion represented by the three electric vector harmonics in the velocity space and higher degree harmonics in the proper-motion space, are eliminated in our analysis by direct subtraction of the reflex solar velocity in its tangential components for each star. The Oort parameters determined by a straightforward least-squares adjustment in vector spherical harmonics are A=14.0 +/- 1.4, B=13.1 +/- 1.2, K=1.1 +/- 1.8, and C=2.9 +/- 1.4 km s(exp -1) kpc(exp -1). The physical meaning and the implications of these parameters are discussed in the framework of a general linear model of the velocity field. We find a few statistically significant higher degree harmonic terms that do not correspond to any parameters in the classical linear model. One of them, a third-degree electric harmonic, is tentatively explained as the response to a negative linear gradient of rotation velocity with distance from the Galactic plane, which we estimate at approximately -20 km s(exp -1) kpc(exp -1). A similar vertical gradient of rotation velocity has been detected for more distant stars representing the thick disk (z greater than 1 kpc), but here we surmise its existence in the thin disk at z less than 200 pc. The most unexpected and unexplained term within the Ogorodnikov-Milne model is the first-degree magnetic harmonic, representing a rigid rotation of the stellar field about the axis -Y pointing opposite to the direction of rotation. This harmonic comes out with a statistically robust coefficient of 6.2 +/- 0.9 km s(exp -1) kpc(exp -1) and is also present in the velocity field of more distant stars. The ensuing upward vertical motion of stars in the general direction of the Galactic center and the downward motion in the anticenter direction are opposite to the vector field expected from the stationary Galactic warp model.

Markarov, V. V.; Murphy, D. W.

2007-01-01

275

Effective ATI channels in high harmonic generation  

NASA Astrophysics Data System (ADS)

Harmonic generation by an atom in a laser field is described by the three-step mechanism as proceeding via above-threshold ionization (ATI) followed by electron propagation in the laser-dressed continuum and subsequent laser-assisted recombination (LAR). The amplitude of the harmonic production is given by the coherent sum of contributions from different intermediate ATI channels labelled by the number, m, of absorbed laser photons. The range of m-values that give a substantial contribution is explored and found to be rather broad for high harmonic generation. The coherence effects are of crucial importance as they are responsible for the characteristic pattern of harmonic intensities with a plateau domain followed by a cut-off region. Due to the multiphoton nature of the process, an efficient summation of m-contributions can be carried out within the framework of the saddle-point method. The saddle points correspond to some complex-valued labels m = mc associated with the intermediate effective ATI channels in the three-step harmonic generation process. The advantage of this approach stems from the fact that summation over a large number of conventional ATI m-channels is replaced by summation over a small number of effective mc-channels. The equation governing mc has a transparent physical meaning: the electron ejected from the atom on the first (ATI) stage should return to the core to make LAR possible. The effective channel labels m move along characteristic trajectories in the complex plane as the system parameters vary. In the cut-off region of the harmonic spectrum a single effective channel contributes. For lower harmonics, in the plateau domain, two effective ATI channels become essential. The interference of their contributions leads to an oscillatory pattern in the harmonic generation rates. The calculated rates are in good agreement with the results obtained by other approaches.

Kuchiev, M. Yu; Ostrovsky, V. N.

2001-02-01

276

Omics integrating physical techniques: Aged Piedmontese meat analysis.  

PubMed

Piedmontese meat tenderness becomes higher by extending the ageing period after slaughter up to 44days. Classical physical analysis only partially explain this evidence, so in order to discover the reason of the potential beneficial effects of prolonged ageing, we performed omic analysis in the Longissimus thoracis muscle by examining main biochemical changes through mass spectrometry-based metabolomics and proteomics. We observed a progressive decline in myofibrillar structural integrity (underpinning meat tenderness) and impaired energy metabolism. Markers of autophagic responses (e.g. serine and glutathione metabolism) and nitrogen metabolism (urea cycle intermediates) accumulated until the end of the assayed period. Key metabolites such as glutamate, a mediator of the appreciated umami taste of the meat, were found to constantly accumulate until day 44. Finally, statistical analyses revealed that glutamate, serine and arginine could serve as good predictors of ultimate meat quality parameters, even though further studies are mandatory. PMID:25442615

Lana, Alessandro; Longo, Valentina; Dalmasso, Alessandra; D'Alessandro, Angelo; Bottero, Maria Teresa; Zolla, Lello

2015-04-01

277

Simulated, Emulated, and Physical Investigative Analysis (SEPIA) of networked systems.  

SciTech Connect

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.

Burton, David P.; Van Leeuwen, Brian P.; McDonald, Michael James; Onunkwo, Uzoma A.; Tarman, Thomas David; Urias, Vincent E.

2009-09-01

278

Topics in statistical data analysis for high-energy physics  

E-print Network

These lectures concern two topics that are becoming increasingly important in the analysis of High Energy Physics (HEP) data: Bayesian statistics and multivariate methods. In the Bayesian approach we extend the interpretation of probability to cover not only the frequency of repeatable outcomes but also to include a degree of belief. In this way we are able to associate probability with a hypothesis and thus to answer directly questions that cannot be addressed easily with traditional frequentist methods. In multivariate analysis we try to exploit as much information as possible from the characteristics that we measure for each event to distinguish between event types. In particular we will look at a method that has gained popularity in HEP in recent years: the boosted decision tree (BDT).

G. Cowan

2010-12-16

279

Nondeducibility-Based Analysis of Cyber-Physical Systems  

NASA Astrophysics Data System (ADS)

Controlling information flow in a cyber-physical system (CPS) is challenging because cyber domain decisions and actions manifest themselves as visible changes in the physical domain. This paper presents a nondeducibility-based observability analysis for CPSs. In many CPSs, the capacity of a low-level (LL) observer to deduce high-level (HL) actions ranges from limited to none. However, a collaborative set of observers strategically located in a network may be able to deduce all the HL actions. This paper models a distributed power electronics control device network using a simple DC circuit in order to understand the effect of multiple observers in a CPS. The analysis reveals that the number of observers required to deduce all the HL actions in a system increases linearly with the number of configurable units. A simple definition of nondeducibility based on the uniqueness of low-level projections is also presented. This definition is used to show that a system with two security domain levels could be considered “nondeducibility secure” if no unique LL projections exist.

Gamage, Thoshitha; McMillin, Bruce

280

Harmonic tori in spheres and complex projective spaces F. E. Burstall  

E-print Network

Harmonic tori in spheres and complex projective spaces F. E. Burstall Introduction A map OE : M ! N of Riemannian manifolds is harmonic if it extremises compact subdomain of M. Harmonic maps arise in many different contexts* * in Geometry and Physics (for

Burstall, Fran E.

281

Harmonic tori in spheres and complex projective spaces F. E. Burstall  

E-print Network

Harmonic tori in spheres and complex projective spaces F. E. Burstall Introduction A map # : M # N of Riemannian manifolds is harmonic if it extremises the energy functional: Z |d#| 2 dvol on every compact subdomain of M . Harmonic maps arise in many di#erent contexts in Geometry and Physics (for an overview, see

Burstall, Fran E.

282

Harmonic tori in symmetric spaces and commuting Hamiltonian systems on loop algebras  

E-print Network

Harmonic tori in symmetric spaces and commuting Hamiltonian systems on loop algebras F. E. Burstall, D. Ferus, F. Pedit, and U. Pinkall Introduction Background The study of harmonic maps of compact and Physics: For example, minimal surfaces are (conformal) harmonic maps while constant mean curvature

283

Harmonic tori in spheres and complex projective spaces F. E. Burstall  

E-print Network

Harmonic tori in spheres and complex projective spaces F. E. Burstall Introduction A map OE : M ! N of Riemannian manifolds is harmonic if it extremises the energy functional: Z jdOEj 2 dvol on every compact subdomain of M . Harmonic maps arise in many different contexts in Geometry and Physics (for an overview

Bath, University of

284

Harmonic tori in spheres and complex projective spaces F. E. Burstall  

E-print Network

Harmonic tori in spheres and complex projective spaces F. E. Burstall Introduction A map : M N of Riemannian manifolds is harmonic if it extremises the energy functional: |d|2 dvol on every compact subdomain of M. Harmonic maps arise in many different contexts in Geometry and Physics (for an overview, see [16

Burstall, Fran E.

285

Search for Harmonic tremor in the Galapagos Jonathan M. Lees, University of North Carolina, Chapel Hill  

E-print Network

Search for Harmonic tremor in the Galapagos Jonathan M. Lees, University of North Carolina, Chapel Hill Harmonic volcano tremor can provide details of conduit physics during magma flow and volcano.71.2 Hz. Harmonic tremor has not been reported on Galapagos volcanoes, possibly because seismic

Geist, Dennis

286

Classical thermodynamics of particles in harmonic traps Martin Ligarea  

E-print Network

Classical thermodynamics of particles in harmonic traps Martin Ligarea Department of Physics 2010 I develop simple thermodynamic relations for a system of noninteracting classical particles defined, and the pressure varies with position, indicating that the thermodynamic relations should

Ligare, Martin

287

Second Harmonic Generation Imaging Microscopy: Applications to Diseases Diagnostics  

PubMed Central

Second Harmonic Generation microscopy has emerged as a powerful new optical imaging modality. This Feature describes its chemical and physical principles and highlights current applications in disease diagnostics. PMID:21446646

Campagnola, Paul

2011-01-01

288

Illustration: The Harmonic Oscillator  

NASA Astrophysics Data System (ADS)

To illustrate the formalism on a simple prototype problem, one may look at the harmonic oscillator. In the spirit of this picture, in fact, one can eschew solving the Schrödinger problem and plugging the wavefunctions into (4)...

Curtright, Thomas L.; Fairlie, David B.; Zachos, Cosmas K.

2014-11-01

289

Harmonic Morphisms -Basics Sigmundur Gudmundsson  

E-print Network

Harmonic Morphisms - Basics Sigmundur Gudmundsson Department of Mathematics Faculty of Science Lund University Sigmundur.Gudmundsson@math.lu.se March 11, 2014 #12;Harmonic Maps in Gaussian Geometry Harmonic Maps in Riemannian Geometry Outline 1 Harmonic Maps in Gaussian Geometry Holomorphic Functions in One

Gudmundsson, Sigmundur

290

Mellin Transforms and Asymptotics: Harmonic Sums  

Microsoft Academic Search

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

Philippe Flajolet; Xavier Gourdon; Philippe Dumas

1995-01-01

291

Intermediate Mechanics Tutorials: Simple Harmonic Motion  

NSDL National Science Digital Library

This set of tutorial materials covers the topic of simple harmonic motion. Students examine qualitatively and quantitatively the motion of a simple harmonic oscillator, as exemplified by a mass attached to an ideal spring. There are two tutorials, one using motion graphs and one using vectors, to describe the motion. Students analyze and solve the differential equations of motion to develop an understanding of the physical parameters in the problem. This material also includes a pretest, example homework, and test questions. This is part of a large collection of similar tutorial materials in intermediate classical mechanics.

Wittmann, Michael C.; Ambrose, Bradley S.

2009-03-31

292

A Proposed Cost-benefit Analysis Model for Physical Form Analysis for a Futuristic Submarine Decision Support System  

E-print Network

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

Cummings, Mary "Missy"

293

Comparative analysis of the high-order harmonic generation in the laser ablation plasmas prepared on the surfaces of complex and atomic targets  

SciTech Connect

We analyzed high-order harmonic generation from the plasma plumes prepared on the surfaces of complex targets. The studies of In-Ag targets showed that the characteristics of the high-order harmonics from the double-target plume were the same as those from the single-target plasmas. For the chromium-tellurium plasma, the enhancements of the 29th and 27th harmonics were obtained, thus indicating the appearance of the enhancement properties from both components of the double-target plasma. These comparative studies also showed higher enhancement of a single harmonic in the case of atomic plasma (Sb) with regard to the molecular one (InSb). The additional component can only decrease the enhancement factor of the medium, due to the change of the oscillator strength and spectral distribution of the transitions involved in the resonance enhancement of the specific harmonic order. The theoretical calculations have shown the enhancement of specific harmonics for the Sb, Te, and Cr plasmas in the double-target configurations.

Ganeev, R. A. [Scientific Association Akadempribor, Academy of Sciences of Uzbekistan, Akademgorodok, Tashkent 100125 (Uzbekistan); Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2008-07-15

294

XII Advanced Computing and Analysis Techniques in Physics Research  

NASA Astrophysics Data System (ADS)

November 2008 will be a few months after the official start of LHC when the highest quantum energy ever produced by mankind will be observed by the most complex piece of scientific equipment ever built. LHC will open a new era in physics research and push further the frontier of Knowledge This achievement has been made possible by new technological developments in many fields, but computing is certainly the technology that has made possible this whole enterprise. Accelerator and detector design, construction management, data acquisition, detectors monitoring, data analysis, event simulation and theoretical interpretation are all computing based HEP activities but also occurring many other research fields. Computing is everywhere and forms the common link between all involved scientists and engineers. The ACAT workshop series, created back in 1990 as AIHENP (Artificial Intelligence in High Energy and Nuclear Research) has been covering the tremendous evolution of computing in its most advanced topics, trying to setup bridges between computer science, experimental and theoretical physics. Conference web-site: http://acat2008.cern.ch/ Programme and presentations: http://indico.cern.ch/conferenceDisplay.py?confId=34666

Speer, Thomas; Carminati, Federico; Werlen, Monique

295

COMBINATION OF PHYSICAL-ORGANIC AND THEORETICAL METHODS IN ELECTRONIC STRUCTURE ANALYSIS. OPPOSING  

E-print Network

COMBINATION OF PHYSICAL-ORGANIC AND THEORETICAL METHODS IN ELECTRONIC STRUCTURE ANALYSIS. OPPOSING significant challenges that can only be met by combination of physical-organic and theoretical methods

Glaser, Rainer

296

Harmonic potential and hadron spectroscopy  

E-print Network

The quark-gluon sea in the hadrons is considered as periodically correlated. Energy levels of Shrodinger equation with harmonic potential is used for describing of the spectrum of hadron masses. In the considered cases the effective potential operating on each particle of ensemble, under certain conditions becomes square-law on displacement from a equilibrium point. It can become an explanation of popularity of oscillator potential for the description of a spectrum of masses of elementary particles. The analysis shows that levels of periodic potential better agreed to the spectrum of hadron masses, than levels of other potentials used for an explanation of a spectrum of masses.

Rafael Tumanyan

2009-05-28

297

Application of higher harmonic blade feathering for helicopter vibration reduction  

NASA Technical Reports Server (NTRS)

Higher harmonic blade feathering for helicopter vibration reduction is considered. Recent wind tunnel tests confirmed the effectiveness of higher harmonic control in reducing articulated rotor vibratory hub loads. Several predictive analyses developed in support of the NASA program were shown to be capable of calculating single harmonic control inputs required to minimize a single 4P hub response. In addition, a multiple-input, multiple-output harmonic control predictive analysis was developed. All techniques developed thus far obtain a solution by extracting empirical transfer functions from sampled data. Algorithm data sampling and processing requirements are minimal to encourage adaptive control system application of such techniques in a flight environment.

Powers, R. W.

1978-01-01

298

Optical harmonic generator  

DOEpatents

A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The extraordinary or e directions of the crystal elements are oriented in the integral assembly to be in quadrature (90/sup 0/). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude o and e components. For a third-harmonic generation, the input fundamental wave has o and e components whose amplitudes are in a ratio of 2:1 (o:e reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10/sup 0/. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axeses (o).

Summers, M.A.; Eimerl, D.; Boyd, R.D.

1982-06-10

299

Optical harmonic generator  

DOEpatents

A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The "extraordinary" or "e" directions of the crystal elements are oriented in the integral assembly to be in quadrature (90.degree.). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude "o" and "e" components. For a third-harmonic generation, the input fundamental wave has "o" and "e" components whose amplitudes are in a ratio of 2:1 ("o":"e" reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10.degree.. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axes ("o").

Summers, Mark A. (Livermore, CA); Eimerl, David (Pleasanton, CA); Boyd, Robert D. (Livermore, CA)

1985-01-01

300

Generalized mode acceleration and modal truncation augmentation methods for the harmonic response analysis of nonviscously damped systems  

NASA Astrophysics Data System (ADS)

The modal truncation problem is frequently encountered in nonviscously (viscoelastically) damped systems since only the modes of interest are usually considered in the dynamic analysis of engineering problems. This study aims at accurately calculating the steady-state responses of nonviscously damped systems by only considering the modes of interest. Based on the Neumann expansion theorem and the frequency shifting technique, a property obtained from the first-order terms of the Neumann expansion of the frequency response function (FRF) matrix of nonviscously damped systems is given. However, this procedure cannot be extended to consider the further higher-order terms. It means a truncation expansion problem exists for nonviscously damped systems. By considering the first-order terms of the Neumann expansion, a generalized mode acceleration method (GMAM) is presented to handle the modal truncation problem. The GMAM can overcome the singular problem of the stiffness matrix. The modal truncation augmentation method (MTAM) is also presented to handle the modal truncation problem by making the equilibrium equations into a subspace equation spanned in terms of the columns of a projection basis given in the GMAM. Several conclusions concerning the implementation of the presented methods are formulated on the basis of the results of three examples.

Li, Li; Hu, Yujin

2015-02-01

301

Differentiation of Col I and Col III Isoforms in Stromal Models of Ovarian Cancer by Analysis of Second Harmonic Generation Polarization and Emission Directionality  

PubMed Central

A profound remodeling of the extracellular matrix occurs in many epithelial cancers. In ovarian cancer, the minor collagen isoform of Col III becomes upregulated in invasive disease. Here we use second harmonic generation (SHG) imaging microscopy to probe structural differences in fibrillar models of the ovarian stroma comprised of mixtures of Col I and III. The SHG intensity and forward-backward ratios decrease with increasing Col III content, consistent with decreased phasematching due to more randomized structures. We further probe the net collagen ?-helix pitch angle within the gel mixtures using what is believed to be a new pixel-based polarization-resolved approach that combines and extends previous analyses. The extracted pitch angles are consistent with those of peptide models and the method has sufficient sensitivity to differentiate Col I from the Col I/Col III mixtures. We further developed the pixel-based approach to extract the SHG signal polarization anisotropy from the same polarization-resolved image matrix. Using this approach, we found that increased Col III results in decreased alignment of the dipole moments within the focal volume. Collectively, the SHG measurements and analysis all indicate that incorporation of Col III results in decreased organization across several levels of collagen organization. Furthermore, the findings suggest that the collagen isoforms comingle within the same fibrils, in good agreement with ultrastructural data. The pixel-based polarization analyses (both excitation and emission) afford determination of structural properties without the previous requirement of having well-aligned fibers, and the approaches should be generally applicable in tissue. PMID:24461010

Tilbury, Karissa; Lien, Chi-Hsiang; Chen, Shean-Jen; Campagnola, Paul J.

2014-01-01

302

Higher order harmonic detection for exploring nonlinear interactions with nanoscale resolution  

PubMed Central

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

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

303

Harmonic reduction in thyristor converters by harmonic current injection  

Microsoft Academic Search

The paper describes analytical and experimental results for a new method of current harmonic reduction in thyristor converters. The principle of the method is to modify the current waveforms on the d.c. windings of the converter transformer by injecting harmonic currents at a particular frequency. In practice, third harmonic currents of the power frequency is most efficient. Experimental results carried

A. Ametani

1976-01-01

304

Structural, Physical, and Compositional Analysis of Lunar Simulants and Regolith  

NASA Technical Reports Server (NTRS)

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.

Greenberg, Paul; Street, Kenneth W.; Gaier, James

2008-01-01

305

Evidence of high harmonics from echo-enabled harmonic generation for seeding x-ray free electron lasers.  

PubMed

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. PMID:22324690

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; Woodley, M

2012-01-13

306

LC-TOOL-2003-015 1 Java Physics Generator and Analysis Modules  

E-print Network

LC-TOOL-2003-015 1 Java Physics Generator and Analysis Modules Michael T. Ronan LBNL, Berkeley, CA) physics event generators are used in de#12;ning a common generator interface package. Portable libraries provide high-level OO study tools. Complete physics generation, parallel detector simulations

307

Generalized Multilevel Physical Optics (MLPO) for Comprehensive Analysis of Reflector Antennas  

Microsoft Academic Search

Recent developments of the multilevel physical optics (MLPO) algorithm aiming at the comprehensive analysis of complex reflector antenna systems are presented. The physical theory of diffraction (PTD) line integral along the rim of a reflector is combined with the physical optics (PO) surface integral within the multilevel algorithm. The multilevel scheme is also generalized to combine fields radiated by various

Christine Letrou; Amir Boag

2012-01-01

308

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.  

SciTech Connect

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.

CHENG,L.HANSON,A.DIAMOND,D.XU,J.CAREW,J.RORER,D.

2004-03-31

309

Experimental Harmonic Motion  

NASA Astrophysics Data System (ADS)

1. Elementary theory of harmonic motion; 2. Experimental work in harmonic motion; Experiment 1. Determination of g by a simple pendulum; Experiment 2. Harmonic motion of a body suspended by a spring; Experiment 3. Harmonic motion of a rigid body suspended by a torsion wire; Experiment 4. Study of a system with variable moment of inertia; Experiment 5. Dynamical determination of ratio of couple to twist for a torsion wire; Experiment 6. Comparison of the moments of inertia of two bodies; Experiment 7. Experiment with a pair of inertia bars; Experiment 8. Determination of the moment of inertia of a rigid pendulum; Experiment 9. Experiment on a pendulum with variable moment of inertia; Experiment 10. Determination of g by a rigid pendulum; Experiment 11. Pendulum on a yielding support; Experiment 12. Determination of the radius of curvature of a concave mirror by the oscillations of a sphere rolling in it; Experiment 13. Determination of g by the oscillations of a rod rolling on a cylinder; Experiment 14. Study of a vibrating system with two degrees of freedom; Note 1. On the vibration of a body suspended from a light spring; Note 2. Periodic time of a pendulum vibrating through a finite arc; Note 3. Periodic time for finite motion; Note 4. Periodic times of a pendulum with two degrees of freedom.

Searle, G. F. C.

2014-05-01

310

Spherical Harmonic class  

NSDL National Science Digital Library

SphericalHarmonic returns the value of P(theta,phi) where theta and phi are defined in terms of a standard spherical coordinate system (phi measures angle (x,y,z) makes with z axis.) The algorithm is taken from Messiah's Quantum Mechanics, but readers should note that Messiah defines theta and phi in opposite order from this implementation.

Joiner, David; The Shodor Education Foundation, Inc.

311

Stress in Harmonic Serialism  

ERIC Educational Resources Information Center

This dissertation proposes a model of word stress in a derivational version of Optimality Theory (OT) called Harmonic Serialism (HS; Prince and Smolensky 1993/2004, McCarthy 2000, 2006, 2010a). In this model, the metrical structure of a word is derived through a series of optimizations in which the "best" metrical foot is chosen…

Pruitt, Kathryn Ringler

2012-01-01

312

HARMONIC MORPHISMS ON HOMOGENEOUS HADAMARD  

E-print Network

HARMONIC MORPHISMS ON HOMOGENEOUS HADAMARD MANIFOLDS JONAS NORDSTRÃ?M Master's thesis 2010:E14;#12;Abstract In this thesis we investigate the existence of complex-valued harmonic morphisms on Lie groups of their Lie algebra. This decomposi- tion allows us to define harmonic morphisms to Rn , n 2. Any homogeneous

Gudmundsson, Sigmundur

313

Analytic Continuation of Harmonic Sums  

E-print Network

We present a method for calculating any (nested) harmonic sum to arbitrary accuracy for all complex values of the argument. The method utilizes the relation between harmonic sums and (derivatives of) Hurwitz zeta functions, which allows a harmonic sum to be calculated as an expansion valid for large values of its argument. A program for implementing this method is also provided.

S. Albino

2009-03-06

314

Fast Harmonic Balance of SIS Mixers with Multiple Junctions and Superconducting Circuits  

E-print Network

Fast Harmonic Balance of SIS Mixers with Multiple Junctions and Superconducting Circuits Frank Rice-47, Pasadena, CA 91125, USA. Abstract We have extended the spectral domain harmonic balance method-Raphson technique to achieve rapid convergence, even when many harmonics are included in the analysis. Another im

Chattopadhyay, Goutam

315

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.  

SciTech Connect

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.

CAREW,J.CHENG,L.HANSON,AXU,J.RORER,D.DIAMOND,D.

2003-08-26

316

A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters  

E-print Network

A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical; the methodology allows large number of design iterations, including both physical design and control variables

Victoria, University of

317

The Use of Interaction Analysis in Describing Instructional Processes in Physical Education.  

ERIC Educational Resources Information Center

A review is presented of research concerning physical education instruction, focusing upon those studies which use interaction analysis as a method of systematically observing the instructional process. A brief overview of the development of interaction analysis systems in physical education cites instruments which were designed for focusing on…

Tinning, Richard I.

318

Physics and Analysis at a Hadron Collider - An Introduction (1/3)  

ScienceCinema

This is the first lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This first lecture provides a brief introduction to hadron collider physics and collider detector experiments as well as offers some analysis guidelines. The lectures are aimed at graduate students.

None

2011-10-06

319

Driven harmonic oscillator as a quantum simulator for open systems  

E-print Network

We show theoretically how a driven harmonic oscillator can be used as a quantum simulator for non-Markovian damped harmonic oscillator. In the general framework, the results demonstrate the possibility to use a closed system as a simulator for open quantum systems. The quantum simulator is based on sets of controlled drives of the closed harmonic oscillator with appropriately tailored electric field pulses. The non-Markovian dynamics of the damped harmonic oscillator is obtained by using the information about the spectral density of the open system when averaging over the drives of the closed oscillator. We consider single trapped ions as a specific physical implementation of the simulator, and we show how the simulator approach reveals new physical insight into the open system dynamics, e.g. the characteristic quantum mechanical non-Markovian oscillatory behavior of the energy of the damped oscillator, usually obtained by the non-Lindblad-type master equation, can have a simple semiclassical interpretation.

Jyrki Piilo; Sabrina Maniscalco

2006-10-03

320

Second harmonic inversion for ultrasound contrast harmonic imaging  

NASA Astrophysics Data System (ADS)

Ultrasound contrast agents (UCAs) are small micro-bubbles that behave nonlinearly when exposed to an ultrasound wave. This nonlinear behavior can be observed through the generated higher harmonics in a back-scattered echo. In past years several techniques have been proposed to detect or image harmonics produced by UCAs. In these proposed works, the harmonics generated in the medium during the propagation of the ultrasound wave played an important role, since these harmonics compete with the harmonics generated by the micro-bubbles. We present a method for the reduction of the second harmonic generated during nonlinear-propagation-dubbed second harmonic inversion (SHI). A general expression for the suppression signals is also derived. The SHI technique uses two pulses, p' and p'', of the same frequency f0 and the same amplitude P0 to cancel out the second harmonic generated by nonlinearities of the medium. Simulations show that the second harmonic is reduced by 40 dB on a large axial range. Experimental SHI B-mode images, from a tissue-mimicking phantom and UCAs, show an improvement in the agent-to-tissue ratio (ATR) of 20 dB compared to standard second harmonic imaging and 13 dB of improvement in harmonic power Doppler.

Pasovic, Mirza; Danilouchkine, Mike; Faez, Telli; van Neer, Paul L. M. J.; Cachard, Christian; van der Steen, Antonius F. W.; Basset, Olivier; de Jong, Nico

2011-06-01

321

High Harmonic Generation at Long Wavelengths  

SciTech Connect

High harmonic radiation spectra up to 19th order in alkali metal vapors excited by an intense, picosecond mid-infrared (3-4 {mu} m ) laser are reported and compared to theory. The strong-field dynamics in the alkali metal atoms exhibit significant differences from all previously studied systems due to the strong coupling between their ground and first excited states. (c) 1999 The American Physical Society.

Sheehy, B. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Martin, J. D. D. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); DiMauro, L. F. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Agostini, P. [SPAM, Centre d'Etudes de Saclay, 91191 Gif Sur Yvette, (France)] [SPAM, Centre d'Etudes de Saclay, 91191 Gif Sur Yvette, (France); Schafer, K. J. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States)] [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States); Gaarde, M. B. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States) [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States); Department of Physics, Lund Institute of Technology, P.O. Box 118, S-22100 Lund, (Sweden); Kulander, K. C. [TAMP, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [TAMP, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1999-12-20

322

Interference effects in two-color high-order harmonic generation  

SciTech Connect

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.

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

323

Developing Skill-Analysis Competency in Physical Education Teachers  

ERIC Educational Resources Information Center

Given the known relationship between physical inactivity and chronic disease (US Dept. of Health and Human Services [USDHHS], 2000, 2001), learning more about antecedents for physical activity engagement is an important research priority. In this vein, a number of studies have found a relationship between perceived and actual motor skill…

Lounsbery, Monica; Coker, Cheryl

2008-01-01

324

Analysis of information flow security in cyber–physical systems  

Microsoft Academic Search

Information flow is a fundamental concept underlying the security of a system. Confidentiality of information in a system can be breached through unrestricted information flow. Physical components added to a cyber system considerably increase the difficulty of determining information flow and the difficulty of mitigating the corresponding confidentiality problem. Fundamentally, physical actions inherently divulge information through simple observation. This work

Ravi Akella; Han Tang; Bruce M. McMillin

2010-01-01

325

Harmonic multiplication using resonant tunneling  

NASA Technical Reports Server (NTRS)

This paper demonstrates the use of resonant-tunneling diodes as varistors for harmonic multiplication. It is shown that efficient odd-harmonic conversion is possible and that even harmonics do not appear because of the antisymmetry of the current-voltage (I-V) curve. It is also shown that, with the proper choice of resonant-tunneling structure and pump amplitude, most of the harmonic output power can be confined to a single odd-harmonic frequency. Fifth-harmonic multiplication was demonstrated with an output at 21.75 GHz and a power conversion efficiency of 0.5 percent, and a fifth-harmonic efficiency of 2.7 percent was achieved in a circuit simulation using an improved I-V curve.

Sollner, T. C. L. G.; Brown, E. R.; Goodhue, W. D.; Correa, C. A.

1988-01-01

326

Nonlinear harmonic generation and devices in doubly resonant Kerr cavities  

E-print Network

We describe a theoretical analysis of the nonlinear dynamics of third-harmonic generation (??3?) via Kerr (?(3)) nonlinearities in a resonant cavity with resonances at both ? and 3?. Such a doubly resonant cavity greatly ...

Hashemi, Hila

327

Three-dimensional simulations of harmonic radiation and harmonic lasing  

SciTech Connect

Characteristics of the harmonic emission from free-electron lasers (FELs) are examined in the spontaneous, coherent-spontaneous and stimulated emission regimes. The radiation at both odd and even harmonic frequencies is treated for electron beams with finite emittance and energy spread. In the spontaneous emission regime, the transverse radiation patterns including the transverse frequency dependences, are given. How this expression is modified to include energy spread and emittance is described. In the coherent-spontaneous emission and stimulated emission regimes, the interaction of the radiation fields with the electrons must be treated self-consistently. Here, a single-frequency distributed transverse source function for each electron is used in the harmonic version of the 3-D code FELEX to model the harmonic radiation. The code has recently been modified to simultaneously model the fundamental and harmonic interactions for multiple-pass oscillator simulations. These modifications facilitate the examination of FELs under various operating conditions. When the FEL is lasing at the fundamental, the evolution of the harmonic fields can be examined. This evolution is unique in the sense that the electron beam radiates at the harmonic frequencies in the presence of the harmonic radiation circulating in the cavity. As a result, enhancements of the harmonic emission can be observed. Finally, harmonic lasing can occur in cases where there is sufficient gain to overcome cavity losses and lasing at the fundamental can be suppressed. The characteristics and efficiency of these interactions are explored. 11 refs., 9 figs.

Schmitt, M.J.; McVey, B.D.

1990-01-01

328

Multi-physics analysis of laser solid freeform fabrication  

NASA Astrophysics Data System (ADS)

The quality of parts fabricated using Laser Solid Freeform Fabrication (LSFF) is highly dependent on the physical phenomena and operating parameters which govern the process. For instance, the thermal stress patterns and intensity, induced throughout the process domain due to the layer-by-layer material deposition and the temperature distribution characteristics, contribute significantly to potential delamination and crack formation across the fabricated part. In this research, some of the main features as well as drawbacks of this technique are studied through a multi-physics analysis of the process. For this purpose, a coupled time-dependent 3D model is developed with which the geometry of the deposited material as well as temperature and thermal stress fields across the process domain can be predicted. In the proposed approach, coupled thermal and stress domains are numerically obtained assuming a decoupled interaction between the laser beam and powder stream. To predict the geometry of the deposited material, once the melt pool boundary is obtained, the process domain is discretized in a cross-sectional fashion based on the powder feed rate, elapsed time, and intersection of the melt pool and powder stream projected on the substrate. Layers of additive material are then added onto the non-planar domain. The main process parameters affected by a multilayer deposition due to the formation of non-planar surfaces, such as powder catchment, are incorporated into the modelling approach to enhance the accuracy of the results. To demonstrate the proposed algorithm and to study the main features of the process, a four-layer thin wall of AISI 304L steel on a substrate of the same material is numerically and experimentally fabricated. The numerical analyses along with the experimental results are then used to investigate the correlation between the temperature-thermal stress fields and crack formation across the fabricated parts. The trend of the results reveals that by preheating the substrate prior to the fabrication process, it is possible to substantially reduce the formed micro-cracks. To demonstrate the feasibility of preheating on the reduction of micro-cracks, several simulations and experiments are performed in which a crack-free result is obtained, with a 22 per cent reduction in thermal stresses when the substrate is preheated to 800 K. The numerical and experimental results are also used to study the circumstances of the microstructural formation during the fabrication process. To conclude this research, the developed modelling approach is further extended to briefly discuss the effects of the path patterns and the main operating parameters on the outcomes of the process. The effects of the material properties and their variations on the temperature distributions and thermal stress fields are studied by fabrication of a thin wall of two Stellite 6 layers and two Ti layers on a stainless steel substrate.

Alimardani, Masoud

329

Harmonically trapped jellium  

E-print Network

We discuss the model of a $D$-dimensional confined electron gas in which the particles are trapped by a harmonic potential. In particular, we study the non-interacting kinetic and exchange energies of finite-size inhomogeneous systems, and compare the resulting Thomas-Fermi and Dirac coefficients with various uniform electron gas paradigms. We show that, in the thermodynamic limit, the properties of this model are identical to those of the $D$-dimensional Fermi gas.

Loos, Pierre-François

2012-01-01

330

Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy  

NASA Astrophysics Data System (ADS)

This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

Loganathan, Muthukumaran; Bristow, Douglas A.

2014-04-01

331

Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy  

SciTech Connect

This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

Loganathan, Muthukumaran; Bristow, Douglas A., E-mail: dbristow@mst.edu [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65401 (United States)

2014-04-15

332

A proposed cost-benefit analysis model for physical form analysis for a futuristic submarine decision support system  

E-print Network

This thesis proposes a model for cost-benefit analysis for physical form selection of a decision support tool, primarily to support system acquisition decisions that need to be made early in the system life cycle. By ...

Bhattacharjee, Dhiman

2007-01-01

333

Electron cyclotron harmonic wave acceleration  

NASA Technical Reports Server (NTRS)

A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

1987-01-01

334

Learning physics: A comparative analysis between instructional design methods  

NASA Astrophysics Data System (ADS)

The purpose of this research was to determine if there were differences in academic performance between students who participated in traditional versus collaborative problem-based learning (PBL) instructional design approaches to physics curricula. This study utilized a quantitative quasi-experimental design methodology to determine the significance of differences in pre- and posttest introductory physics exam performance between students who participated in traditional (i.e., control group) versus collaborative problem solving (PBL) instructional design (i.e., experimental group) approaches to physics curricula over a college semester in 2008. There were 42 student participants (N = 42) enrolled in an introductory physics course at the research site in the Spring 2008 semester who agreed to participate in this study after reading and signing informed consent documents. A total of 22 participants were assigned to the experimental group (n = 22) who participated in a PBL based teaching methodology along with traditional lecture methods. The other 20 students were assigned to the control group (n = 20) who participated in the traditional lecture teaching methodology. Both the courses were taught by experienced professors who have qualifications at the doctoral level. The results indicated statistically significant differences (p < .01) in academic performance between students who participated in traditional (i.e., lower physics posttest scores and lower differences between pre- and posttest scores) versus collaborative (i.e., higher physics posttest scores, and higher differences between pre- and posttest scores) instructional design approaches to physics curricula. Despite some slight differences in control group and experimental group demographic characteristics (gender, ethnicity, and age) there were statistically significant (p = .04) differences between female average academic improvement which was much higher than male average academic improvement (˜63%) in the control group which may indicate that traditional teaching methods are more effective in females, whereas there was no significant difference noted in the experimental group between male and female participants. There was a statistically significant and negative relationship (r = -.61, p = .01) between age and physics pretest scores in the control group. No statistical analyses yielded significantly different average academic performance values in either group as delineated by ethnicity.

Mathew, Easow

335

Analysis of physical human-robot interaction for motor learning with physical help  

Microsoft Academic Search

In this paper we investigate physical human-robot interaction (PHRI) as an important extension of traditional HRI research. The aim of this research is to develop a humanoid robot that can work in the same spaces as humans. We first propose a new control system that takes advantage of inherent joint flexibility. The control system is applied on a new humanoid

Shuhei Ikemoto; Takashi Minato; Hiroshi Ishiguro

2008-01-01

336

Towards automated biomedical ontology harmonization.  

PubMed

The use of biomedical ontologies is increasing, especially in the context of health systems interoperability. Ontologies are key pieces to understand the semantics of information exchanged. However, given the diversity of biomedical ontologies, it is essential to develop tools that support harmonization processes amongst them. Several algorithms and tools are proposed by computer scientist for partially supporting ontology harmonization. However, these tools face several problems, especially in the biomedical domain where ontologies are large and complex. In the harmonization process, matching is a basic task. This paper explains the different ontology harmonization processes, analyzes existing matching tools, and proposes a prototype of an ontology harmonization service. The results demonstrate that there are many open issues in the field of biomedical ontology harmonization, such as: overcoming structural discrepancies between ontologies; the lack of semantic algorithms to automate the process; the low matching efficiency of existing algorithms; and the use of domain and top level ontologies in the matching process. PMID:24851964

Uribe, Gustavo A; Lopez, Diego M; Blobel, Bernd

2014-01-01

337

A Practical Guide to Data Analysis for Physical Science Students  

Microsoft Academic Search

This textbook is intended for undergraduates who are carrying out laboratory experiments in the physical sciences for the first time. It is a practical guide on how to analyze data and estimate errors. The necessary formulas for performing calculations are given, and the ideas behind them are explained, although this is not a formal text on statistics. Specific examples are

Louis Lyons

1991-01-01

338

Children's stereotypical perceptions of physical activities: a K-12 analysis.  

PubMed

The purpose of this study was to examine grade (K-12) and gender differences for 638 children in stereotyping physical activities. Boys were more stereotypical in perceptions than girls. Children in Kindergarten, Grade 2, and Grade 8 were more stereotypical in perceptions than those in Grades 4, 6, 10, and 12. PMID:7898998

Pellett, T L

1994-12-01

339

Instrumental physical analysis of microwaved glycerol citrate foams  

Technology Transfer Automated Retrieval System (TEKTRAN)

Solid polyester glyceride polymers generated by microwave cooking were further cured in a conventional oven at 100 oC for 0, 6, 24, 48, or 72 hr and their physical properties were tested. Curing polyester glycerides resulted in decreased moisture content (MC), altered color, increased hydrated polym...

340

Analysis of Self-Directed Mastery Learning of Honors Physics  

ERIC Educational Resources Information Center

Self-directed learning (SDL) is an important life skill in a knowledge-based society and prepares students to persist, manage their time and resources, use logic to construct their knowledge, argue their views, and collaborate. The purpose of this study was to facilitate mastery of physics concepts through self-directedness in formative testing…

Athens, Wendy

2011-01-01

341

Accuracy of a hybrid Fast Physical Optics scheme for the analysis of dual reflector antennas  

Microsoft Academic Search

A novel hybrid Fast Physical Optics (FPO) algorithm for the analysis of dual reflector antennas is presented. A two-level FPO algorithm for the subreflector to main reflector propagation is proposed and combined with the multilevel FPO that is used for the main reflector to far-field computation. The accuracy of the proposed method is studied by comparison with the direct physical

Christine Letrou; Amir Boag

2006-01-01

342

A Multi-Dimensional Cognitive Analysis of Undergraduate Physics Students' Understanding of Heat Conduction  

ERIC Educational Resources Information Center

This study proposes a multi-dimensional approach to investigate, represent, and categorize students' in-depth understanding of complex physics concepts. Clinical interviews were conducted with 30 undergraduate physics students to probe their understanding of heat conduction. Based on the data analysis, six aspects of the participants' responses…

Chiou, Guo-Li; Anderson, O. Roger

2010-01-01

343

Qualitative Analysis of Distributed Physical Systems with Applications to Control Synthesis \\Lambda  

E-print Network

Qualitative Analysis of Distributed Physical Systems with Applications to Control Synthesis \\Lambda fields. Analyzing and controlling these physical processes and systems are common tasks in many and controllability. This paper develops an ontological abstraction and a structure­based design mechanism

Bailey-Kellogg, Chris

344

Harmonic oscillators and resonance series generated by a periodic unstable classical orbit  

NASA Technical Reports Server (NTRS)

The presence of an unstable periodic classical orbit allows one to introduce the decay time as a purely classical magnitude: inverse of the Lyapunov index which characterizes the orbit instability. The Uncertainty Relation gives the corresponding resonance width which is proportional to the Planck constant. The more elaborate analysis is based on the parabolic equation method where the problem is effectively reduced to the multidimensional harmonic oscillator with the time-dependent frequency. The resonances form series in the complex energy plane which is equidistant in the direction perpendicular to the real axis. The applications of the general approach to various problems in atomic physics are briefly exposed.

Kazansky, A. K.; Ostrovsky, Valentin N.

1995-01-01

345

Nonlinear harmonic generation in free-electron lasers with helical wigglers.  

PubMed

It is widely believed that harmonics are suppressed in helical wigglers. However, linear harmonic generation (LHG) occurs by an azimuthal resonance that excites circularly polarized, off-axis waves, where the hth harmonic varies as exp((ihtheta). Nonlinear harmonic generation (NHG) is driven by bunching at the fundamental and has different properites from LHG. While NHG has been studied in planar wigglers, there has been no analysis of NHG in helical wigglers. The 3D simulation code medusa has been modified for this purpose, and it is shown that NHG is substantial in helical wigglers and that the even and odd harmonics have comparable intensities. PMID:15783822

Freund, H P; O'Shea, P G; Biedron, S G

2005-02-25

346

HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report  

SciTech Connect

Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

1982-09-01

347

Physics  

NSDL National Science Digital Library

Physics is the scientific study of the basic principles of the universe, including matter, energy, motion and force, and their interactions. Major topics include classical mechanics, thermodynamics, light and optics, electromagnetism and relativity.

K-12 Outreach,

348

Fourier Analysis of Musical Intervals  

ERIC Educational Resources Information Center

Use of a microphone attached to a computer to capture musical sounds and software to display their waveforms and harmonic spectra has become somewhat commonplace. A recent article in "The Physics Teacher" aptly demonstrated the use of MacScope in just such a manner as a way to teach Fourier analysis. A logical continuation of this project is to…

LoPresto, Michael C.

2008-01-01

349

PHYSICAL REVIEW B 85, 174110 (2012) Crystal structures, strain analysis, and physical properties of Sr0.7Ce0.3MnO3  

E-print Network

PHYSICAL REVIEW B 85, 174110 (2012) Crystal structures, strain analysis, and physical properties been an extensive number of studies on the perovskite-type manganites in recent years, owing­3 The fascinating physical properties displayed by this class of materials are largely attributed to the strong

Cambridge, University of

350

Engaging Students in a Physics Course through Use of Digital Video Capture and Analysis  

NASA Astrophysics Data System (ADS)

Use of digital video motion analysis as a teaching tool in an introductory physics course is presented. The focus of the presentation is the application of digital video technology in a Physics for Movement Science course geared towards Physical Education, Athletic Training and Exercise Science majors. The Dickinson movie set was found to be the most applicable for in-class activities, homework assignments, and projects. Some of the movie clips chosen for analysis are focused on human motion and sports. Additionally, students are starting to capture and analyze their own movie clips.

Lojewska, Zenobia

2007-10-01

351

6.728 Applied Quantum and Statistical Physics, Fall 2002  

E-print Network

Elementary quantum mechanics and statistical physics. Introduces applied quantum physics. Emphasizes experimental basis for quantum mechanics. Applies Schrodinger's equation to the free particle, tunneling, the harmonic ...

Bulovic, Vladimir, 1970-

352

Harmonic Series Meets Fibonacci Sequence  

ERIC Educational Resources Information Center

The terms of a conditionally convergent series may be rearranged to converge to any prescribed real value. What if the harmonic series is grouped into Fibonacci length blocks? Or the harmonic series is arranged in alternating Fibonacci length blocks? Or rearranged and alternated into separate blocks of even and odd terms of Fibonacci length?

Chen, Hongwei; Kennedy, Chris

2012-01-01

353

Harmonic sources and filtering approaches  

Microsoft Academic Search

This article presents 22 configurations of power filters for the harmonic compensation of nonlinear loads. Some of these configurations are novel and result from the newly discovered characteristics of nonlinear loads and circuitry duality, while the others are well known and used in practice. Nonlinear loads can be characterized into two types of harmonic sources: current-source nonlinear loads and voltage-source

F. Z. Peng

2001-01-01

354

DEPARTMENT OF PHYSICS Physics 32100  

E-print Network

to one- electron atoms, atomic shell structure and periodic table; nuclear physics, relativity the significance of the Pauli exclusion principle and the periodic table. 7. understand how quantum mechanics, harmonic oscillator, hydrogen atom again, etc. 6. Pauli exclusion principle and the periodic table 7

Lombardi, John R.

355

Robustness Analysis for Battery Supported Cyber-Physical Systems  

E-print Network

This paper establishes a novel analytical approach to quantify robustness of scheduling and battery management for battery supported cyber-physical systems. A dynamic schedulability test is introduced to determine whether tasks are schedulable within a finite time window. The test is used to measure robustness of a real-time scheduling algorithm by evaluating the strength of computing time perturbations that break schedulability at runtime. Robustness of battery management is quantified analytically by an adaptive threshold on the state of charge. The adaptive threshold significantly reduces the false alarm rate for battery management algorithms to decide when a battery needs to be replaced.

Zhang, Fumin; Mukhopadhyay, Shayok

2011-01-01

356

Analysis of the physical atomic forces between noble gas atoms, alkali ions and halogen ions  

NASA Technical Reports Server (NTRS)

The physical forces between atoms and molecules are important in a number of processes of practical importance, including line broadening in radiative processes, gas and crystal properties, adhesion, and thin films. The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base for the dispersion forces is developed from the literature based on evaluations with the harmonic oscillator dispersion model for higher order coefficients. The Zener model of the repulsive core is used in the context of the recent asymptotic wave functions of Handler and Smith; and an effective ionization potential within the Handler and Smith wave functions is defined to analyze the two body potential data of Waldman and Gordon, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent.

Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

1986-01-01

357

Harmonization of laboratory testing - Current achievements and future strategies.  

PubMed

Harmonization in laboratory testing is more far-reaching than merely analytical harmonization. It includes all aspects of the total testing process from the "pre-pre-analytical" phase through analysis to the "post-post-analytical" phase. Harmonizing the pre-analytical phase requires use of standardized operating procedures for correct test selection, sample collection and handling, while standardized test terminology, and units and traceability to ISO standard 17511 are required to ensure equivalency of measurement results. Use of harmonized reference intervals and decision limits for analytes where platforms share allowable bias requirements will reduce inaccurate clinical interpretation and unnecessary laboratory testing. In the post-analytical phase, harmonized procedures for the management of critical laboratory test results are required to improve service quality and ensure patient safety. Monitoring of the outcomes of harmonization activities is through surveillance by external quality assessment schemes that use commutable materials and auditing of the "pre-pre-analytical" and "post-post-analytical" phases. Successful implementation of harmonization in laboratory testing requires input by all stakeholders, including the clinical laboratory community, diagnostics industry, clinicians, professional societies, IT providers, consumer advocate groups and governmental bodies. PMID:24001695

Tate, Jillian R; Johnson, Roger; Barth, Julian; Panteghini, Mauro

2014-05-15

358

High-field harmonic generation in helium  

SciTech Connect

We observe harmonics of 526-nm laser light up to the 45th order, 11.7 nm, in helium. We discuss the extension of the harmonic plateau with increasing laser intensity. The data suggest that the highest harmonic order produced depends on the highest intensity seen by the atom before photoionization. Harmonics are generated predominantly from neutrals. Harmonic generation from ions is weak owing to poor phase matching between the fundamental and harmonic fields at high electron densities.

Crane, J.K.; Perry, M.D.; Herman, S. (Laser Program, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)); Falcone, R.W. (Department of Physics, University of California, Berkeley, Berkeley, California 94720 (United States))

1992-09-15

359

Hydrogen Generation from Water Disassociation Using Small Currents and Harmonics Trien N. Nguyen1  

E-print Network

Hydrogen Generation from Water Disassociation Using Small Currents and Harmonics Trien N. Nguyen1 1 Department of Physics, Purdue School of Science Hydrogen can be produced cheaply and efficiently from water sources using a combination of harmonics and small currents. Hydrogen is a clean and virtually

Zhou, Yaoqi

360

Tabletop coherent diffractive microscopy with extreme ultraviolet light from high harmonic generation  

E-print Network

Tabletop coherent diffractive microscopy with extreme ultraviolet light from high harmonic,22761 Hamburg, Germany; c Department of Physics and Astronomy and California NanoSystems Institute, University a tabletop source of extreme ultraviolet (EUV) light from high harmonic generation at 29 nm and 13.5 nm. High

Miao, Jianwei "John"

361

ChroMirror: A Real-Time Interactive Mirror for Chromatic and Color-Harmonic Dressing  

E-print Network

and color-harmonic clothes. Keywords Ubiquitous computing, home computing, interactive design, color appropriate clothing color combinations. By digitally rendering a mirror image of the user wearing clothing variety of chromatic and color-harmonic clothing combinations (i.e., without having to physically change

Ouhyoung, Ming

362

Object Oriented Component Framework for Experimental Data Analysis in Nuclear Physics  

NASA Astrophysics Data System (ADS)

Object-oriented data analysis system was implemented under Oberon System environment. The system is designed for efficient analysis of data from multidetector Nuclear Physics experiments. Other application areas, such as spectroscopy, are also possible. T Work supported by the U.S. DOE, grant number DE-FG02-88ER40414.

Skulski, Wojciech

1997-08-01

363

A physically oriented approach to analysis and mapping of terroirs  

Microsoft Academic Search

The identification of viticulture terroir is an important issue, strongly rooted on soil science, that has major impact on vineyard management and, through marketing, on farmer income. The concept of terroir is well established but still ambiguous. Nowadays, a unique methodology to the analysis and implementation of terroirs does not exist but most of the approaches are based on a

A. Bonfante; A. Basile; G. Langella; P. Manna; F. Terribile

2011-01-01

364

Physical and Chemical Analytical Analysis: A key component of Bioforensics  

Microsoft Academic Search

The anthrax letters event of 2001 has raised our awareness of the potential importance of non-biological measurements on samples of biological agents used in a terrorism incident. Such measurements include a variety of mass spectral, spectroscopic, and other instrumental techniques that are part of the current armamentarium of the modern materials analysis or analytical chemistry laboratory. They can provide morphological,

S. P. Velsko

2005-01-01

365

Geometry Description Markup Language for Physics Simulation And Analysis Applications.  

SciTech Connect

The Geometry Description Markup Language (GDML) is a specialized XML-based language designed as an application-independent persistent format for describing the geometries of detectors associated with physics measurements. It serves to implement ''geometry trees'' which correspond to the hierarchy of volumes a detector geometry can be composed of, and to allow to identify the position of individual solids, as well as to describe the materials they are made of. Being pure XML, GDML can be universally used, and in particular it can be considered as the format for interchanging geometries among different applications. In this paper we will present the current status of the development of GDML. After having discussed the contents of the latest GDML schema, which is the basic definition of the format, we will concentrate on the GDML processors. We will present the latest implementation of the GDML ''writers'' as well as ''readers'' for either Geant4 [2], [3] or ROOT [4], [10].

Chytracek, R.; /CERN; McCormick, J.; /SLAC; Pokorski, W.; /CERN; Santin, G.; /European Space Agency

2007-01-23

366

Survival Analysis in Amputees Based on Physical Independence Grade Achievement  

PubMed Central

Backgound Survival implications of achieving different grades of physical independence after lower extremity amputation are unknown. Objectives To identify thresholds of physical independence achievement associated with improved 6-month survival and to identify and compare other risk factors after removing the influence of the grade achieved. Design Data were combined from 8 administrative databases. Grade was measured on the basis of 13 individual self-care and mobility activities measured at inpatient rehabilitation discharge. Setting Ninety-nine US Department of Veterans Affairs Medical Centers. Patients Retrospective longitudinal cohort study of 2616 veterans who underwent lower extremity amputation and subsequent inpatient rehabilitation between October 1, 2002, and September 30, 2004. Main Outcome Measure Cumulative 6-month survival after rehabilitation discharge. Results The 6-month survival rate (95% confidence interval [CI]) for those at grade 1 (total assistance) was 73.5% (70.5%-76.2%). The achievement of grade 2 (maximal assistance) led to the largest incremental improvement in prognosis with survival increasing to 91.1% (95% CI, 85.6%-94.5%). In amputees who remained at grade 1, the 30-day hazards ratio for survival compared with grade 6 (independent) was 43.9 (95% CI, 10.8-278.2), sharply decreasing with time. Whereas metastatic cancer and hemodialysis remained significantly associated with reduced survival (both P ? .001), anatomical amputation level was not significant when rehabilitation discharge grade and other diagnostic conditions were considered. Conclusions Even a small improvement to grade 2 in the most severely impaired amputees resulted in better 6-month survival. Health care systems must plan appropriate interdisciplinary treatment strategies for both medical and functional issues after amputation. PMID:19528388

Stineman, Margaret G.; Kurichi, Jibby E.; Kwong, Pui L.; Maislin, Greg; Reker, Dean M.; Bruce Vogel, W.; Prvu-Bettger, Janet A.; Bidelspach, Douglas E.; Bates, Barbara E.

2010-01-01

367

Harmonic-Oscillator-Based Effective Theory  

E-print Network

I describe harmonic-oscillator-based effective theory (HOBET) and explore the extent to which the effects of excluded higher-energy oscillator shells can be represented by a contact-gradient expansion in next-to-next-to-leading order (NNLO). I find the expansion can be very successful provided the energy dependence of the effective interaction, connected with missing long-wavelength physics associated with low-energy breakup channels, is taken into account. I discuss a modification that removes operator mixing from HOBET, simplifying the task of determining the parameters of an NNLO interaction.

W. C. Haxton

2006-08-06

368

Impact of SG damper windings on small-signal stability of a distorted SMIB including time and space harmonics  

Microsoft Academic Search

This paper investigates the impact of synchronous generator's damper windings on small-signal stability and dynamic behavior of power systems in the presence of time and space harmonics. A Distorted Single Machine Infinite Bus (DSMIB) system is used for the analysis. A nonlinear model of the synchronous generator (SG) in the Harmonic Domain (HD) is used to include space harmonics. The

M. Ladjavardi; M. A. S. Masoum; S. M. Islam

2008-01-01

369

HARMONIC FUNCTIONS FOR SEA-SURFACE TEMPERATURES AND SALINITIES, KOKO HEAD, OAHU, 1956-69, AND SEA-SURFACE  

E-print Network

HARMONIC FUNCTIONS FOR SEA-SURFACE TEMPERATURES AND SALINITIES, KOKO HEAD, OAHU, 1956-69, AND SEA-SURFACE TEMPERATURES, CHRISTMAS ISLAND, 1954-69 GUNTHER It SECKEL' AND MARIAN Y. Y. YONG' ABSTRACT Harmonic functions, with daily sampling, are on average 0.07° C. Harmonic analysis spanning the entire sampling duration shows

370

Effect of harmonics coherence in resonant transition radiation  

NASA Astrophysics Data System (ADS)

In the present work an essential difference is revealed between the undulator and transition radiation processes. In the first case emission of a photon occurs at a certain angle, while in the second case radiation takes place with equal probability in both dense and dilute parts of the medium and at various angles. These angles are different for different harmonics and their angular widths, which determine the frequency spectrum of radiation, do not depend on the harmonic number. The higher harmonic the wider the frequency ranges of emission. The weighting function of overlap of the harmonic spectra has a sharp peak in the soft range of frequencies. The peak increases and its width quadratic decreases depending on the electron energy. Therefore, the number of emitted soft photons does not depend on the energy and quadratic depends on the number of harmonics. A new physical phenomenon has been revealed: coherent emission of harmonics in the soft frequency range. Thus, it is possible to obtain intense beams of soft photons using high-current electron bunches.

Gevorgian, Lekdar

2007-05-01

371

Scatter in nonlinear ultrasonic measurements due to crystallographic orientation change induced anisotropy in harmonics generation  

NASA Astrophysics Data System (ADS)

Present study endeavors to establish the physical basis of an unprecedented trend in scatter, observed in nonlinear ultrasonic (NLU) parameter, associated with varying degree of crystallographic orientation change across crystallites in a polycrystalline material. It is shown that this scatter arises due to anisotropy in harmonics generation as a result of orientation change of slip systems in polycrystals with respect to the wave propagation direction. A near ? titanium alloy has been taken as a model alloy to demonstrate this effect of crystallographic orientation change vis-à-vis change in the orientation of slip systems. Scale of crystal orientation change is shown to have a strong correlation with the degree of scatter in NLU measurements. Further, the study establishes the dominating effect of the scale of crystalline orientation change on harmonics generation as compared to variation in other microstructural parameters such as dislocation density, interface structure etc. Frequency distribution analysis of the scatter indicates that the distribution depends on the colony size which exhibits a linear correlation with standard deviation value. The dislocation string vibration model has been extended for harmonics generation in polycrystalline aggregates to explain the trend in the scatter during measurement of NLU parameter in the material.

Mukhopadhyay, Amretendu; Sarkar, Rajdeep; Punnose, Sony; Valluri, Jitendra; Nandy, T. K.; Balasubramaniam, Krishnan

2012-03-01

372

Spherical harmonics and integration in superspace  

NASA Astrophysics Data System (ADS)

In this paper, the classical theory of spherical harmonics in {\\bb R}^m is extended to superspace using techniques from Clifford analysis. After defining a super-Laplace operator and studying some basic properties of polynomial null-solutions of this operator, a new type of integration over the supersphere is introduced by exploiting the formal equivalence with an old result of Pizzetti. This integral is then used to prove orthogonality of spherical harmonics of different degree, Green-like theorems and also an extension of the important Funk-Hecke theorem to superspace. Finally, this integration over the supersphere is used to define an integral over the whole superspace, and it is proven that this is equivalent with the Berezin integral, thus providing a more sound definition of the Berezin integral.

DeBie, H.; Sommen, F.

2007-06-01

373

Physical optics analysis of a 4-reflector antenna, part 2  

NASA Technical Reports Server (NTRS)

The results of a rigorous analysis of the Deep Space Network (DSN) 70-m antenna S-band (2.295-GHz) RF performance are presented. Previous estimation of 1.6 dB S-band gain improvement of the 70-m antenna over the 64-m antenna has been revised to 1.5 dB by this analysis. The S-band right circularly polarized (RCP) beam position offset relative to X-band (8.45-GHz) beam position is predicted to be 0.0045 deg. (0.04 beamwidth). The effective S-band gain loss resulting from non-coincidence with the X-band is predicted to be 0.02 dB. Therefore, this is no longer a concern for the 64-m to 70-m upgrade project.

Cha, A. G.

1986-01-01

374

Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction  

NASA Technical Reports Server (NTRS)

An approach was developed which allows for design studies of commercial aircraft using physics-based noise analysis methods while retaining the ability to perform the rapid trade-off and risk analysis studies needed at the conceptual design stage. A prototype integrated analysis process was created for computing the total aircraft EPNL at the Federal Aviation Regulations Part 36 certification measurement locations using physics-based methods for fan rotor-stator interaction tones and jet mixing noise. The methodology was then used in combination with design of experiments to create response surface equations (RSEs) for the engine and aircraft performance metrics, geometric constraints and take-off and landing noise levels. In addition, Monte Carlo analysis was used to assess the expected variability of the metrics under the influence of uncertainty, and to determine how the variability is affected by the choice of engine cycle. Finally, the RSEs were used to conduct a series of proof-of-concept conceptual-level design studies demonstrating the utility of the approach. The study found that a key advantage to using physics-based analysis during conceptual design lies in the ability to assess the benefits of new technologies as a function of the design to which they are applied. The greatest difficulty in implementing physics-based analysis proved to be the generation of design geometry at a sufficient level of detail for high-fidelity analysis.

Olson, Erik D.; Mavris, Dimitri N.

2006-01-01

375

Interaction and learning: An analysis of two freshman physics courses  

NASA Astrophysics Data System (ADS)

The influence of digital technology has gradually increased through the years to the point where it impacts almost every part of our experience in some way. Educators are expected increasingly to supplement or even replace lecture and chalkboard practices with alternative strategies. Beyond integrating new technologies into the learning environments are the new forms of learning that some believe are implied by the nature of digitally mediated instruction itself. The use of multimedia technologies for learning in many cases is thought to facilitate a move away from teacher-centered practices of instruction toward learner-centered strategies of both delivery and assessment. This study was an investigation of effects that may be encountered when alternative forms of classroom delivery are introduced. It was a mixed-mode investigation of classroom culture and student performance in two sections of a physics course for undergraduate engineering students. The content for these two classes was identical as were the learning resources available to students. Both classes employed multiple methods of presentation combining face-to-face methods with classroom and online digital learning tools. The most distinctive differences between them were found in the classroom practice itself. One class received what may be called a traditional teacher-centered presentation focusing on solving math problems in physics. The other employed dense student to instructor and student-to-student interaction in the classroom with a learning approach characterized by inquiry methods of content delivery. The investigation asked three questions. First it sought to identify what expectations students brought to the classroom about what they would experience and how they would be taught. Second it examined how the tools and practices used to facilitate learning actually affected the classroom culture. Finally the study explored what affect if any the pedagogical practices students experienced had on their measured performance outcomes. These students were strongly influenced by their teacher-centered background and were not expecting any new learning strategies. They found significantly different classroom cultures between the two classes and achieved performance results that clearly were affected by the delivery techniques they experienced.

Clark, Dexter

2005-08-01

376

Non-collinear high-order harmonic generation by three interfering laser beams.  

PubMed

High order harmonic generation (HHG) has shown its impact on several applications in Attosecond Science and Atomic and Molecular Physics. Owing to the complexity of the experimental setup for the generation and characterization of harmonics, as well as to the large computational costs of numerical modelling, HHG is generally performed and modelled in collinear geometry. Recently, several experiments have been performed exploiting non-collinear geometry, such as HHG in a grating of excited molecules created by crossing beams. In such studies, harmonics were observed at propagation directions different from those of the driving pulses; moreover the scattered harmonics were angularly dispersed.In this work we report on a new regime of HHG driven by multiple beams, where the harmonics are generated by three synchronized, intense laser pulses organized in a non-planar geometry. Although the configuration we explore is well within the strong-field regime, the scattered harmonics we observe are not angularly dispersed. PMID:25606907

Negro, M; Devetta, M; Faccialá, D; Ciriolo, A G; Calegari, F; Frassetto, F; Poletto, L; Tosa, V; Vozzi, C; Stagira, S

2014-12-01

377

Global analysis of predicted proteomes: Functional adaptation of physical properties  

PubMed Central

The physical characteristics of proteins are fundamentally important in organismal function. We used the complete predicted proteomes of >100 organisms spanning the three domains of life to investigate the comparative biology and evolution of proteomes. Theoretical 2D gels were constructed with axes of protein mass and charge (pI) and converted to density estimates comparable across all types and sizes of proteome. We asked whether we could detect general patterns of proteome conservation and variation. The overall pattern of theoretical 2D gels was strongly conserved across all life forms. Nevertheless, coevolved replicons from the same organism (different chromosomes or plasmid and host chromosomes) encode proteomes more similar to each other than those from different organisms. Furthermore, there was disparity between the membrane and nonmembrane subproteomes within organisms (proteins of membrane proteomes are on the average more basic and heavier) and their variation across organisms, suggesting that membrane proteomes evolve most rapidly. Experimentally, a significant positive relationship independent of phylogeny was found between the predicted proteome and Biolog profile, a measure associated with the ecological niche. Finally, we show that, for the smallest and most alkaline proteomes, there is a negative relationship between proteome size and basicity. This relationship is not adequately explained by AT bias at the DNA sequence level. Together, these data provide evidence of functional adaptation in the properties of complete proteomes. PMID:15150418

Knight, Christopher G.; Kassen, Rees; Hebestreit, Holger; Rainey, Paul B.

2004-01-01

378

Experimental Development and Physical Analysis of Jet and Vortex Actuators  

NASA Technical Reports Server (NTRS)

The Vortex generator consists of a cavity with a lightweight actuator plate. The actuator plate acts like a piston pumping air out of the cavity on the down-stroke and sucking air into the cavity on the upstroke. The actuator is placed asymmetrically over the cavity opening, forming narrow and wide slots when viewed from the top. The actuator depending on amplitude, frequency, and slot spacing produces several flow fields (free jet, wall jet, vortex flow). Computational simulation of the actuator-generated flows have been developed and applied to several actuator flow modes. The objectives of this paper are to study the physics of the actuator-induced flow and to develop computational simulations of the actuatorgenerated flows. This work should provide an impetus for designing similar active flow control systems suitable for aircraft applications. The computational simulation uses a time-accurate full Navier-Stokes (NS) solver known as FTNS3D (a full NS version of CFL3D solver). A Multi-block moving grid has been developed and used for the computational study of the flow fields produced by the vortex generator. For three-dimensional computations, ten multi-block grids are used and for two-dimensional computations, six multiblock grids are used. The grid blocks adjacent to the actuator plate move with the plate motion, and second-order interpolation is used along the block interfaces. Periodic response of the flow has been observed to develop after three cycles of the plate sinusoidal motion.

Kandil, Osama A.; Yang, Zhi; Lachowicz, Jason T.

2000-01-01

379

A Simple Mechanical Model for the Isotropic Harmonic Oscillator  

ERIC Educational Resources Information Center

A constrained elastic pendulum is proposed as a simple mechanical model for the isotropic harmonic oscillator. The conceptual and mathematical simplicity of this model recommends it as an effective pedagogical tool in teaching basic physics concepts at advanced high school and introductory undergraduate course levels. (Contains 2 figures.)

Nita, Gelu M.

2010-01-01

380

Simulating Harmonic Oscillator and Electrical Circuits: A Didactical Proposal  

ERIC Educational Resources Information Center

A Mathematica[TM] package is described that uses simulations and animations to illustrate key concepts in harmonic oscillation and electric circuits for students not majoring in physics or mathematics. Students are not required to know the Mathematica[TM] environment: a user-friendly interface with buttons functionalities and on-line help allows…

Albano, Giovannina; D'Apice, Ciro; Tomasiello, Stefania

2002-01-01

381

Linear harmonic oscillator in spaces with degenerate metrics  

E-print Network

With the help of contraction method we study the harmonic oscillator in spaces with degenerate metrics, namely, on Galilei plane and in the flat 3D Cayley-Klein spaces $R_3(j_2,j_3).$ It is shown that the inner degrees of freedom are appeared which physical dimensions are different from the dimension of the space.

N. A. Gromov

2006-03-02

382

Origin of Shape Resonance in Second-Harmonic Generation from  

E-print Network

-harmonic wave (SHW) mode within the nanoscale air hole. It reveals that several physical mechanisms, including the FW mode excitation amplitude, FW-SHW modal spatial overlap, FW-SHW mode phase mismatch, and SHW mode to the reduction of the group velocity34 . Therefore a clarified microscopic picture about the shape resonance

Wang, Wei Hua

383

Polarization attractors in harmonic mode-locked fiber laser.  

PubMed

We report on a polarimetry of harmonic mode-locked erbium-doped fiber laser with carbon nanotubes saturable absorber. We find new types of vector solitons with locked, switching and precessing states of polarization. The underlying physics presents interplay between birefringence of a laser cavity created by polarization controller along with light induced anisotropy caused by polarization hole burning. PMID:24977612

Habruseva, Tatiana; Mou, Chengbo; Rozhin, Alex; Sergeyev, Sergey V

2014-06-16

384

Power Quality/Harmonic Detection: Harmonic Control in Electric Power Systems for the Telecommunications Industry  

E-print Network

the origin and causes of harmonics, the bad effects of harmonics, the acceptable harmonic distortion limits in the telecommunication power system and the best methods for harmonic detection and mitigation. DEFINING THE PROBLEM Harmonics are currents...POWER QUALITY/HARMONIC DETECTION: HARMoNIc CONTROL IN ELECTRIC POWER SYSTEMS FOR THE TELECOMMUNICATIONS INDUSTRY J. L. "Jim" Felkner Power Equipment Engineer MCI Communications Corporation Richardson, Texas 75082 ABSTRACT The control...

Felkner, L. J.; Waggoner, R. M.

385

Physical Sciences Division Interactive Plotting and Analysis Pages  

NSDL National Science Digital Library

This website provides access to atmospheric and climatological data from a variety of National Oceanic & Atmospheric Administration sources. It also contains numerous tools for retrieving and displaying the data. You can either download raw data or use the tools to construct finished data products. The user is asked to enter such information as type of analysis, time-scale, dataset, variability, and time range of data. Web pages that meet the entered criteria are then generated, and include monthly/seasonal composites, linear monthly/seasonal correlations, daily composites, United States climate division maps, time-section plots, wavelets, chi corrected heating atlas, daily data plots, and others.

386

Tru-Alarm: Trustworthiness Analysis of Sensor Networks in Cyber-Physical Systems  

Microsoft Academic Search

A Cyber-Physical System (CPS) integrates physical devices (e.g., sensors, cameras) with cyber (or informational)components to form a situation-integrated analytical system that responds intelligently to dynamic changes of the real-world scenarios. One key issue in CPS research is trustworthiness analysis of the observed data: Due to technology limitations and environmental influences, the CPS data are inherently noisy that may trigger many

Lu-An Tang; Xiao Yu; Sangkyum Kim; Jiawei Han; Chih-Chieh Hung; Wen-Chih Peng

2010-01-01

387

Intensive physical activity and alexithymia: results from swimmers' discourse analysis.  

PubMed

The aim of this study was to describe and understand the relationship of swimmers' practice intensity and alexithymia features in discourse. This study investigated psychological processes in two groups of male swimmers training at different intensities. The first group was composed of 10 Expert amateurs (M age = 19.5 yr., SD = 1.9), who were competing at the national or international level and trained 22 hours per week. The second group was composed of 10 Amateur swimmers (M age = 20.5 yr., SD = 1.4), who competed at the regional level and trained 6 hours per week. The discourse of swimmers was analysed using the ALCESTE (Analyse de Lexèmes Coocurents dans les Enoncés Simples d'un Texte) method of discourse analysis. Discourse analysis was performed on speech samples produced by swimmers. All the swimmers showed alexithymic verbal behaviour as regards both the means of expression used and the feelings and emotions expressed. This lack of articulateness was more pronounced in the Expert than in the Amateur group. The difference of alexithymic features in correlation with the intensity of sport practice raises the question of the health benefits of intense sports practice and the need for psychological assessment of athletes. PMID:17886500

Allegre, Benjamin; Noel-Jorand, Marie-Christine; Souville, Marc; Pellegrin, Liliane; Therme, Pierre

2007-06-01

388

PREFACE: 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT2013)  

NASA Astrophysics Data System (ADS)

This volume of Journal of Physics: Conference Series is dedicated to scientific contributions presented at the 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2013) which took place on 16-21 May 2013 at the Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China. The workshop series brings together computer science researchers and practitioners, and researchers from particle physics and related fields to explore and confront the boundaries of computing and of automatic data analysis and theoretical calculation techniques. This year's edition of the workshop brought together over 120 participants from all over the world. 18 invited speakers presented key topics on the universe in computer, Computing in Earth Sciences, multivariate data analysis, automated computation in Quantum Field Theory as well as computing and data analysis challenges in many fields. Over 70 other talks and posters presented state-of-the-art developments in the areas of the workshop's three tracks: Computing Technologies, Data Analysis Algorithms and Tools, and Computational Techniques in Theoretical Physics. The round table discussions on open-source, knowledge sharing and scientific collaboration stimulate us to think over the issue in the respective areas. ACAT 2013 was generously sponsored by the Chinese Academy of Sciences (CAS), National Natural Science Foundation of China (NFSC), Brookhaven National Laboratory in the USA (BNL), Peking University (PKU), Theoretical Physics Cernter for Science facilities of CAS (TPCSF-CAS) and Sugon. We would like to thank all the participants for their scientific contributions and for the en- thusiastic participation in all its activities of the workshop. Further information on ACAT 2013 can be found at http://acat2013.ihep.ac.cn. Professor Jianxiong Wang Institute of High Energy Physics Chinese Academy of Science Details of committees and sponsors are available in the PDF

Wang, Jianxiong

2014-06-01

389

Harmonic Oscillators, Heisenberg's Uncertainty Principle and Simultaneous Measurement Precision for Position and Momentum  

E-print Network

There is no question as to the validity of Heisenberg's uncertainty principle, which follows from an abstract analysis of the tenets of quantum mechanics. Herein, however, we reconsider the implications of Heisenberg's Uncertainty Principle for the simultaneous measurement of position and momentum. We show that one can, with a suitable modification of the Fourier transform (which reflects the specifics of the system mass and force constant), obtain a data analysis kernel that enables one to improve significantly the simultaneous measurement precision for position and momentum for the particular harmonic oscillator under study. Our results show that 1) the simultaneous precision for measuring the position and the corresponding momentum depends on the physical parameters of the harmonic oscillator under study 2) one can simultaneously squeeze coherent states by the same amount in both x and wave number, k. The results also suggest that each physical system may, in fact, determine its own optimum transform between representations of non-commuting observables so as to decrease their simultaneous measurement uncertainty limit.

Donald J. Kouri

2014-09-16

390

Investigating Student Communities with Network Analysis of Interactions in a Physics Learning Center  

E-print Network

Developing a sense of community among students is one of the three pillars of an overall reform effort to increase participation in physics, and the sciences more broadly, at Florida International University. The emergence of a research and learning community, embedded within a course reform effort, has contributed to increased recruitment and retention of physics majors. Finn and Rock [1] link the academic and social integration of students to increased rates of retention. We utilize social network analysis to quantify interactions in Florida International University's Physics Learning Center (PLC) that support the development of academic and social integration,. The tools of social network analysis allow us to visualize and quantify student interactions, and characterize the roles of students within a social network. After providing a brief introduction to social network analysis, we use sequential multiple regression modeling to evaluate factors which contribute to participation in the learning community. ...

Brewe, Eric; Sawtelle, Vashti

2011-01-01

391

Investigating Student Communities with Network Analysis of Interactions in a Physics Learning Center  

NSDL National Science Digital Library

We describe our initial efforts at implementing social network analysis to visualize and quantify student interactions in Florida International University's Physics Learning Center. Developing a sense of community among students is one of the three pillars of an overall reform effort to increase participation in physics, and the sciences more broadly, at FIU. Our implementation of a research and learning community, embedded within a course reform effort, has led to increased recruitment and retention of physics majors. Finn and Rock [1997] link the academic and social integration of students to increased rates of retention. To identify these interactions, we have initiated an investigation that utilizes social network analysis to identify primary community participants. Community interactions are then characterized through the network's density and connectivity, shedding light on learning communities and participation. Preliminary results, further research questions, and future directions utilizing social network analysis are presented.

Brewe, Eric; Kramer, Laird H.; O'Brien, George

2010-01-19

392

The analysis of frequency-dependent characteristics for fluid detection: a physical model experiment  

NASA Astrophysics Data System (ADS)

According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a high-frequency bright spot as the amplitude energy shifts. However, it is a low-frequency shadow for the Class III AVO reservoirs saturated with hydrocarbons. In this paper, we verified the high-frequency bright spot results of Chapman for the Class I AVO response using the frequency-dependent analysis of a physical model dataset. The physical model is designed as inter-bedded thin sand and shale based on real field geology parameters. We observed two datasets using fixed offset and 2D geometry with different fluidsaturated conditions. Spectral and time-frequency analyses methods are applied to the seismic datasets to describe the response characteristics for gas-, water-, and oil-saturation. The results of physical model dataset processing and analysis indicate that reflection wave tuning and fluid-related dispersion are the main seismic response characteristic mechanisms. Additionally, the gas saturation model can be distinguished from water and oil saturation for Class I AVO utilizing the frequency-dependent abnormal characteristic. The frequency-dependent characteristic analysis of the physical model dataset verified the different spectral response characteristics corresponding to the different fluid-saturated models. Therefore, by careful analysis of real field seismic data, we can obtain the abnormal spectral characteristics induced by the fluid variation and implement fluid detection using seismic data directly.

Chen, Shuang-Quan; Li, Xiang-Yang; Wang, Shang-Xu

2012-06-01

393

Approximations to toroidal harmonics  

SciTech Connect

Toroidal harmonics P/sub n-1/2/ (cosh ) and Q/sub n-1/2/ (cosh ) are useful in solutions to Maxwell's equations in toroidal coordinates. In order to speed their computation, a set of approximations has been developed that is valid over the range 0 < < infinity. The functional form used for these approximations is dictated by their behavior as 0 and as infinity, and is similar to that used by Hastings in his approximations to the elliptic integrals K and E. This report lists approximations of several mathematical forms with varying numbers of terms; approximations to the above Legendre functions are given for n = 0 through 6. Coefficients of each expansion have been adjusted to distribute the relative error in equi-amplitude peaks over some range, typically .05 < < 5, and in the best cases these peaks are less than 10 . The simple method used to determine the approximations is described. Relative error curves are also presented, obtained by comparing approximations to the more accurate values computed by direct summation of the hypergeometric series.

Pribyl, P.A.

1985-10-01

394

Harmonic functions over group actions Renato Feres  

E-print Network

Harmonic functions over group actions Renato Feres Washington University Renato Feres Washington University () Harmonic functions over group actions 1 / 25 #12;Topics: Harmonic functions and random walks on discrete groups The Liouville property and Poisson boundary Harmonic functions over group actions Examples

Feres, Renato

395

HARMONIC TWOSPHERES IN COMPACT SYMMETRIC SPACES, REVISITED  

E-print Network

HARMONIC TWO­SPHERES IN COMPACT SYMMETRIC SPACES, REVISITED F. E. Burstall and M. A. Guest Introduction The purpose of this article is to give a new description of harmonic maps from the two­sphere S 2 of such harmonic maps occur when G=K = S n or CP n . In 1967, E. Calabi gave a construction of all harmonic maps

Bath, University of

396

Harmonic Broadcasting Is Optimal Lars Engebretsen  

E-print Network

Harmonic Broadcasting Is Optimal Lars Engebretsen Madhu Sudan Abstract Harmonic broadcasting-on-demand broadcasting. In this paper, we note that harmonic broadcasting is actually a special case of the priority argument--that it is impossible to achieve the design goals of harmonic broadcasting using a shorter

Sudan, Madhu

397

On The Harmonic Oscillator Group  

E-print Network

We discuss the maximum kinematical invariance group of the quantum harmonic oscillator from a view point of the Ermakov-type system. A six parameter family of the square integrable oscillator wave functions, which seems cannot be obtained by the standard separation of variables, is presented as an example. The invariance group of generalized driven harmonic oscillator is shown to be isomorphic to the corresponding Schroedinger group of the free particle.

Raquel M. Lopez; Sergei K. Suslov; Jose M. Vega-Guzman

2011-12-04

398

Echo-Enabled Harmonic Generation  

SciTech Connect

A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

Stupakov, Gennady; /SLAC

2012-06-28

399

Azimuthal anisotropy: The higher harmonics  

SciTech Connect

We report the first observations of the fourth harmonic (v{sub 4}) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v{sub 4} is about a factor of 10 smaller than v{sub 2}. For the sixth (v{sub 6}) and eighth (v{sub 8}) harmonics upper limits on the magnitudes are reported.

Poskanzer, Arthur M.; STAR Collaboration

2004-03-12

400

Analysis of carrier behavior in ?-NPD/P(VDF-TrFE) double-layer capacitor by using electric-field-induced optical second-harmonic generation  

NASA Astrophysics Data System (ADS)

The effect of ferroelectric polymer on carrier behaviors in indium-tin oxide (ITO)/poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/N,N?-di-[(1-naphthyl)-N,N?-diphenyl]-(1,1?-biphenyl)-4,4?-diamine (?-NPD)/Au structure was investigated. The internal electric field in ?-NPD introduced by the dipole moments from ferroelectric P(VDF-TrFE) together with the ?-NPD/P(VDF-TrFE) interface accumulated charges plays an important role in the carrier motion in ?-NPD. In displacement current measurement (DCM), two asymmetric peaks and reduced polarization resulting from a large injection barrier from Au electrode to ?-NPD layer were observed. Coupled with the electric-field-induced optical second-harmonic generation (EFISHG) measurement, the electric field in ?-NPD layer was directly probed and gave a support that only part of the dipoles in P(VDF-TrFE) was polarized. We proposed that the formation of an amorphous insulating layer between amorphous ?-NPD layer and partially crystallized P(VDF-TrFE) layer markedly decreased the voltage directly applied on the P(VDF-TrFE) film and caused a reduced polarization. Our findings here will be helpful in analyzing the carrier behavior in organic electronic devices using ferroelectric layers.

Cui, Xiaojin; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

2014-02-01

401

Analysis of carrier behavior in C60/P(VDF-TrFE) double-layer capacitor by using electric-field-induced optical second-harmonic generation measurement  

SciTech Connect

By using displacement current measurement (DCM) and electric-field-induced optical second-harmonic generation (EFISHG) measurement, we studied the carrier behavior in the indium-tin oxide (ITO)/Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))/C60/Au(or Al) capacitors. Two DCM peaks appeared asymmetrically at around ?35.5?V and +30.0?V in the dark. Correspondingly, the EFISHG response from the C60 layer was observed, but the peak positions were different with respect to DCM ones. The results show that the spontaneous polarization of the ferroelectric P(VDF-TrFE) polymeric layer directly affects the electric field in the C60 layer, and thus governs the carrier motion in this layer. As a result, the C60 layer serves like an insulator in the dark, while electrons and holes are captured and released at the interface in response to the turn-over of spontaneous polarization of ferroelectric layer. On the other hand, under white light illumination, C60 layer serves like a conductor due to the increase of photogenerated mobile carriers, and these carriers dominate the carrier motions therein. Our findings here will be helpful for analyzing carrier behaviors in organic electronic devices using ferroelectric polymers.

Cui, Xiaojin [Department of Physical Electronics, Tokyo Institute of Technology 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

2013-12-21

402

Analytical and numerical analysis of a rotational invariant D = 2 harmonic oscillator in the light of different noncommutative phase-space configurations  

NASA Astrophysics Data System (ADS)

In this work we have investigated some properties of classical phase-space with symplectic structures consistent, at the classical level, with two noncommutative (NC) algebras: the Doplicher-Fredenhagen-Roberts algebraic relations and the NC approach which uses an extended Hilbert space with rotational symmetry. This extended Hilbert space includes the operators ? ij and their conjugate momentum ? ij operators. In this scenario, the equations of motion for all extended phase-space coordinates with their corresponding solutions were determined and a rotational invariant NC Newton's second law was written. As an application, we treated a NC harmonic oscillator constructed in this extended Hilbert space. We have showed precisely that its solution is still periodic if and only if the ratio between the frequencies of oscillation is a rational number. We investigated, analytically and numerically, the solutions of this NC oscillator in a two-dimensional phase-space. The result led us to conclude that noncommutativity induces a stable perturbation into the commutative standard oscillator and that the rotational symmetry is not broken. Besides, we have demonstrated through the equations of motion that a zero momentum ? ij originated a constant NC parameter, namely, ? ij = const., which changes the original variable characteristic of ? ij and reduces the phase-space of the system. This result shows that the momentum ? ij is relevant and cannot be neglected when we have that ? ij is a coordinate of the system.

Abreu, Everton M. C.; Marcial, Mateus V.; Mendes, Albert C. R.; Oliveira, Wilson

2013-11-01

403

Intermediate Mechanics Tutorials: Harmonic motion in two dimensions  

NSDL National Science Digital Library

This set of tutorial materials covers the topic of simple harmonic motion in two dimensions. Students examine qualitatively and quantitatively the motion of a 2D harmonic oscillator, as exemplified by a mass attached to an ideal spring. There are two interactive spreadsheets to allow students to manipulate values and graphically see the results. Students alter phase angles and material constants to develop an understanding of the physical parameters in the problem. This material also includes a pretest, example homework, and test questions. This is part of a large collection of similar tutorial materials in intermediate classical mechanics.

Wittmann, Michael C.; Ambrose, Bradley S.

2010-02-03

404

On the harmonic oscillator properties in a twisted Moyal plane  

E-print Network

This work prolongs, using an operator method, the investigations started in our recent paper J. Math. Phys. 51., 102108 on the spectrum and states of the harmonic oscillator on twisted Moyal plane, where rather a Moyal-star-algebraic approach was used. The physical spectrum and states of the harmonic oscillator on twisted Moyal space, obtained here by solving the corresponding differential equation, are similar to those of the ordinary Moyal space, with different parameters. This fortunately contrasts with the previous study which produced unexpected results, i.e. infinitely degenerate states with energies depending on the coordinate functions.

Ezinvi Baloitcha; Mahouton Norbert Hounkonnou; Dine Ousmane Samary

2012-03-25

405

Electromagnetic ion beam instabilities - Growth at cyclotron harmonic wave numbers  

NASA Technical Reports Server (NTRS)

The linear theory of electromagnetic ion beam instabilities for arbitrary angles of propagation is studied, with an emphasis on the conditions necessary to generate unstable modes at low harmonics of the ion cyclotron resonance condition. The present results extend the analysis of Smith et al. (1985). That paper considered only the plasma parameters at a time during which harmonic wave modes were observed in the earth's foreshock. The parameters of that paper are used as the basis of parametric variations here to establish the range of beam properties which may give rise to observable harmonic spectra. It is shown that the growth rates of both left-hand and right-hand cyclotron harmonic instabilities are enhanced by an increase in the beam temperature anisotropy and/or the beam speed. Decreases in the beam density and/or the core-ion beta reduce the overall growth of the cyclotron harmonic instabilities but favor the growth of these modes over the growth of the nonresonant instability and thereby enhance the observability of the harmonics.

Smith, Charles W.; Gary, S. Peter

1987-01-01

406

Associations between sedentary behaviour and physical activity in children and adolescents: a meta-analysis  

PubMed Central

Physical activity and sedentary behaviour are associated with metabolic and mental health during childhood and adolescence. Understanding the inter-relationships between these behaviours will help to inform intervention design. This systematic review and meta-analysis synthesized evidence from observational studies describing the association between sedentary behaviour and physical activity in young people (<18?years). English-language publications up to August 2013 were located through electronic and manual searches. Included studies presented statistical associations between at least one measure of sedentary behaviour and one measure of physical activity. One hundred sixty-three papers were included in the meta-analysis, from which data on 254 independent samples was extracted. In the summary meta-analytic model (k?=?230), a small, but significant, negative association between sedentary behaviour and physical activity was observed (r?=??0.108, 95% confidence interval [CI]?=??0.128, ?0.087). In moderator analyses, studies that recruited smaller samples (n?physical activity; r?=??0.233, 95% CI?=??0.330, ?0.137) or were assessed to be of higher methodological quality (r?=??0.176, 95% CI?=??0.215, ?0.138) reported stronger associations, although effect sizes remained small. The association between sedentary behaviour and physical activity in young people is negative, but small, suggesting that these behaviours do not directly displace one another. PMID:24844784

Pearson, N; Braithwaite, R E; Biddle, S J H; van Sluijs, E M F; Atkin, A J

2014-01-01

407

Associations between sedentary behaviour and physical activity in children and adolescents: a meta-analysis.  

PubMed

Physical activity and sedentary behaviour are associated with metabolic and mental health during childhood and adolescence. Understanding the inter-relationships between these behaviours will help to inform intervention design. This systematic review and meta-analysis synthesized evidence from observational studies describing the association between sedentary behaviour and physical activity in young people (<18?years). English-language publications up to August 2013 were located through electronic and manual searches. Included studies presented statistical associations between at least one measure of sedentary behaviour and one measure of physical activity. One hundred sixty-three papers were included in the meta-analysis, from which data on 254 independent samples was extracted. In the summary meta-analytic model (k?=?230), a small, but significant, negative association between sedentary behaviour and physical activity was observed (r?=?-0.108, 95% confidence interval [CI]?=?-0.128, -0.087). In moderator analyses, studies that recruited smaller samples (n?physical activity; r?=?-0.233, 95% CI?=?-0.330, -0.137) or were assessed to be of higher methodological quality (r?=?-0.176, 95% CI?=?-0.215, -0.138) reported stronger associations, although effect sizes remained small. The association between sedentary behaviour and physical activity in young people is negative, but small, suggesting that these behaviours do not directly displace one another. PMID:24844784

Pearson, N; Braithwaite, R E; Biddle, S J H; van Sluijs, E M F; Atkin, A J

2014-08-01

408

Physics of the Cosmos Program Analysis Group (PhysPAG) Report  

NASA Astrophysics Data System (ADS)

The Physics of the Cosmos Program Analysis Group (PhysPAG) serves as a forum for soliciting and coordinating input and analysis from the scientific community in support of the PCOS program objectives. I will outline the activities of the PhysPAG over the past year, since the last meeting during the AAS meeting in National Harbor, and mention the activities of the PhysPAG related Scientific Interest Groups.

Nousek, John A.

2015-01-01

409

Meta-analysis of internet-delivered interventions to increase physical activity levels  

PubMed Central

Many internet-delivered physical activity behaviour change programs have been developed and evaluated. However, further evidence is required to ascertain the overall effectiveness of such interventions. The objective of the present review was to evaluate the effectiveness of internet-delivered interventions to increase physical activity, whilst also examining the effect of intervention moderators. A systematic search strategy identified relevant studies published in the English-language from Pubmed, Proquest, Scopus, PsychINFO, CINHAL, and Sport Discuss (January 1990 – June 2011). Eligible studies were required to include an internet-delivered intervention, target an adult population, measure and target physical activity as an outcome variable, and include a comparison group that did not receive internet-delivered materials. Studies were coded independently by two investigators. Overall effect sizes were combined based on the fixed effect model. Homogeneity and subsequent exploratory moderator analysis was undertaken. A total of 34 articles were identified for inclusion. The overall mean effect of internet-delivered interventions on physical activity was d?=?0.14 (p?=?0.00). Fixed-effect analysis revealed significant heterogeneity across studies (Q?=?73.75; p?=?0.00). Moderating variables such as larger sample size, screening for baseline physical activity levels and the inclusion of educational components significantly increased intervention effectiveness. Results of the meta-analysis support the delivery of internet-delivered interventions in producing positive changes in physical activity, however effect sizes were small. The ability of internet-delivered interventions to produce meaningful change in long-term physical activity remains unclear. PMID:22546283

2012-01-01

410

Physically-Based, Real-Time Visualization and Constraint Analysis in Multidisciplinary Design  

E-print Network

Physically-Based, Real-Time Visualization and Constraint Analysis in Multidisciplinary Design the performance, lowering the lifecycle cost and shortening product design time for complex systems.1 to improved designs as well as much faster design turnaround time. As the problems considered become more

Peraire, Jaime

411

Bayesian Time Series: Models and Computations for the Analysis of Time Series in the Physical Sciences  

Microsoft Academic Search

. This articles discusses developments in Bayesian time series modellingand analysis relevant in studies of time series in the physical and engineeringsciences. With illustrations and references, we discuss: Bayesian inferenceand computation in various state-space models, with examples in analysingquasi-periodic series; isolation and modelling of various components of error intime series; decompositions of time series into significant latent subseries; nonlineartime series

Mike West

1995-01-01

412

PHYS 301 --Introduction to Mathematical Physics Chapter 6 Vector Analysis (Helmholtz Theorem)  

E-print Network

PHYS 301 -- Introduction to Mathematical Physics Chapter 6 Vector Analysis (Helmholtz Theorem) (i' theorem (Ampère's law). The fact that we can find such a decomposition for F is called the Helmholtz theorem (or Helmholtz decomposition). (ii) If F falls off to zero fast enough as r , the decomposition

Ng, Chung-Sang

413

Student Trajectories in Physics: The Need for Analysis through a Socio-Cultural Lens  

ERIC Educational Resources Information Center

An analysis of student connections through time and space relative to the core discipline of physics is attempted, as viewed through the lens of actor-network-theory, by Antonia Candela. Using lenses of cultural realities, networks, and perceived power in the discourse of one specific university in the capital city of Mexico and one undergraduate…

Zapata, Mara

2010-01-01

414

The Development and Analysis of a Grade Eight Physical Science Test.  

ERIC Educational Resources Information Center

This 46-question multiple choice test deals with the physical and chemical properties of matter, wave motion and types of energy, simple machines, equipment safety and measurement. The test is meant for administration to grade 8 students before and after instruction. Item analysis of the pre- post data are included, as are reliability estimates…

Singh, Balwant; And Others

415

American Institute of Aeronautics and Astronautics Physics Based Analysis of Horseshoe Plasma Actuator for Improving  

E-print Network

1 American Institute of Aeronautics and Astronautics Physics Based Analysis of Horseshoe Plasma. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. #12;2 American Institute of Aeronautics and Astronautics I. Introduction rossflow jets have been widely used in many

Roy, Subrata

416

Evaluation of the Tire Industry of China based on Physical Input–Output Analysis  

Microsoft Academic Search

SummaryWith the rapid development of the rubber industry and its downstream sectors in China, the resulting sharp increase in the number of scrap tires is creating great environmental pressure. By considering the tire production, consumption, collection, and reuse processes as a whole system of tire material flows, and based on physical input–output analysis (IOA), this article analyzes the status quo

Ning YANG; Dingjiang CHEN; Shanying HU; Yourun LI; Yong JIN

2010-01-01

417

Destructive Physical Analysis of Flight- and Ground-Tested Sodium-Sulfur Cells  

NASA Technical Reports Server (NTRS)

Destructive physical analysis (DPA) was used to study the effects of microgravity on the sulfur electrode in sodium-sulfur cells. The cells examined in this work were provided by the Air Force Research Laboratory (AFRL) from their program on sodium-sulfur technology. The Naval Research Laboratory (NRL) provided electrical characterization of the flight-tested and ground-tested cells.

Wasz, Margot L.; Carter, Boyd J.; Donet, Charles M.; Baldwin, Richard S.

1999-01-01

418

Analysis of the RATAN600 radiotelescope antenna with a multilevel Physical Optics algorithm  

Microsoft Academic Search

The RATAN-600 antenna is a flexible multireflector system composed of reflectors of very large dimensions. An extended system, with improved performance in the millimetric range, includes a focal receiver array. Accurate electromagnetic analysis of such a system, and simulation of three-dimensional (3D) patterns, represents a substantial computational challenge. A fast Physical Optics method based on a multilevel subdivision of the

Christine Letrou; Vladimir Khaikin; Amir Boag

419

Equivalence of physical optics and aperture field integration method in the full pattern analysis  

Microsoft Academic Search

Physical optics (PO) and the aperture field integration method (AFIM) are high frequency approximation methods which are widely used for the analysis of reflector antennas. For an offset reflector, PO predicts asymmetric far field patterns in the offset plane, while AFIM in choosing the integration plane normal to the boresight direction always predicts symmetric patterns which are generally inaccurate. AFIM,

I. Oodo; Makoto Ando

1994-01-01

420

Climate Change Impacts and Adaptation Analysis How to Link Physical Climate Data and Economic Studies  

E-print Network

Climate Change Impacts and Adaptation Analysis ­ How to Link Physical Climate Data and Economic There are a number of structural and conceptual differences between the information provided by climate change models of economic concepts applied to climate change impact and adaptation policy assessment, and to illustrate how

421

Theoretical Analysis of Microtubules Dynamics Using a Physical-Chemical Description of Hydrolysis  

E-print Network

Theoretical Analysis of Microtubules Dynamics Using a Physical- Chemical Description of Hydrolysis. They can be viewed as dynamic polymers that function in nonequilibrium conditions stimulated by hydrolysis-chemical description of GTP hydrolysis is presented, in which the hydrolysis rate at a given monomer depends

422

Examination of Trends and Evidence-Based Elements in State Physical Education Legislation: A Content Analysis  

ERIC Educational Resources Information Center

Objectives: To develop a comprehensive inventory of state physical education (PE) legislation, examine trends in bill introduction, and compare bill factors. Methods: State PE legislation from January 2001 to July 2007 was identified using a legislative database. Analysis included components of evidence-based school PE from the Community Guide and…

Eyler, Amy A.; Brownson, Ross C.; Aytur, Semra A.; Cradock, Angie L.; Doescher, Mark; Evenson, Kelly R.; Kerr, Jacqueline; Maddock, Jay; Pluto, Delores L.; Steinman, Lesley; Tompkins, Nancy O'Hara; Troped, Philip; Schmid, Thomas L.

2010-01-01

423

Physical geonomics: Combining the exergy and Hubbert peak analysis for predicting mineral resources depletion  

Microsoft Academic Search

This paper shows how thermodynamics and in particular the exergy analysis can help to assess the degradation degree of earth's mineral resources. The resources may be physically assessed as its exergy content as well as the exergy required for replacing them from a complete degraded state to the conditions in which they are currently presented in nature. In this paper,

Alicia Valero; Antonio Valero

2010-01-01

424

Data Analysis and Graphing in an Introductory Physics Laboratory: Spreadsheet versus Statistics Suite  

ERIC Educational Resources Information Center

Two methods of data analysis are compared: spreadsheet software and a statistics software suite. Their use is compared analysing data collected in three selected experiments taken from an introductory physics laboratory, which include a linear dependence, a nonlinear dependence and a histogram. The merits of each method are compared. (Contains 7…

Peterlin, Primoz

2010-01-01

425

Modeling and Analysis of Safety-Critical Cyber Physical Systems using State/Event Fault Trees  

E-print Network

in a common model. To evaluate our approach, we apply it on a case study of a tire pressure monitoring system. Through their logical gates and hierarchical decomposition they are intuitively understandable. Due in safety analysis. Especially in the eld of cyber physical systems (CPSs), where numerous interfaces come

Paris-Sud XI, Université de

426

The Importance of Physical Fitness versus Physical Activity for Coronary Artery Disease Risk Factors: A Cross-Sectional Analysis.  

ERIC Educational Resources Information Center

This cross-sectional study examined relationships among physical fitness, physical activity, and risk factors for coronary artery disease (CAD) in male police officers. Data from screenings and physical fitness assessments indicated physical activity must be sufficient to influence fitness before obtaining statistically significant risk-reducing…

Young, Deborah Rohm; Steinhardt, Mary A.

1993-01-01

427

Second harmonic generation from tyrosine containing peptides  

NASA Astrophysics Data System (ADS)

The Second Harmonic Generation (SHG) response from Tyrosine-containing peptides at the air-water interface is presented. First, the quadratic hyperpolarizability of the aromatic amino acid Tyrosine obtained by Hyper Rayleigh Scattering is reported, demonstrating its potentiality as an endogenous molecular probe for SHG studies. Then, the single Tyrosine antimicrobial peptide Mycosubtilin is monitored at the air-water interface and compared to another peptide, Surfactin, lacking a Tyrosine residue. Adsorption kinetics and polarization analysis of the SHG intensity for the peptide monolayers clearly demonstrate that the SHG response from Mycosubtilin arises from Tyrosine. Besides, it confirms that indeed Tyrosine can be targeted as an endogenous molecular probe.

Nasir, M. N.; Bergmann, E.; Benichou, E.; Russier-Antoine, I.; Lascoux, N.; Jonin, Ch.; Besson, F.; Brevet, P. F.

2013-10-01

428

Polarization peculiarities of femtosecond laser induced harmonic generation from solid surface plasma  

NASA Astrophysics Data System (ADS)

Polarization characteristics of harmonic generation from solid surface plasma were studied using a femtosecond CPA Ti:S-Nd:glass laser. The ratios between the harmonics intensities produced by p-polarized and s-polarized pump were 25 and 6 for the second and fifth harmonics, respectively, at pump intensities ( I) below 10 17 W cm -2. The same ratios decreased to 2.4 and 1.5 for I>2×10 17 W cm -2. This decrease was explained by the rippling caused by Rayleigh-Taylor-like instability at the critical density surface, and Faraday rotation effect due to the influence of the spontaneous magnetic fields generated in plasma. Theoretical analysis of s- and p-polarization-induced harmonic generation was presented using LPIC code. The blueshift of the harmonics has been also observed. It was found that the blueshift increases with the harmonic order.

Ganeev, R. A.; Ishizawa, A.; Kanai, T.; Ozaki, T.; Kuroda, H.

2003-11-01

429

A use of regression analysis in acoustical diagnostics of gear drives  

NASA Technical Reports Server (NTRS)

A study is presented of components of the vibration spectrum as the filtered first and second harmonics of the tooth frequency which permits information to be obtained on the physical characteristics of the vibration excitation process, and an approach to be made to comparison of models of the gearing. Regression analysis of two random processes has shown a strong dependence of the second harmonic on the first, and independence of the first from the second. The nature of change in the regression line, with change in loading moment, gives rise to the idea of a variable phase shift between the first and second harmonics.

Balitskiy, F. Y.; Genkin, M. D.; Ivanova, M. A.; Kobrinskiy, A. A.; Sokolova, A. G.

1973-01-01

430

On the measurement of a weak classical force coupled to a harmonic oscillator: experimental progress  

SciTech Connect

Several high-precision physics experiments are approaching a level of sensitivity at which the intrinsic quantum nature of the experimental apparatus is the dominant source of fluctuations limiting the sensitivity of the measurements. This quantum limit is embodied by the Heisenberg uncertainty principle, which prohibits arbitrarily precise simultaneous measurements of two conjugate observables of a system but allows one-time measurements of a single observable with any precision. The dynamical evolution of a system immediately following a measurement limits the class of observables that may be measured repeatedly with arbitrary precision, with the influence of the measurement apparatus on the system being confined strictly to the conjugate observables. Observables having this feature, and the corresponding measurements performed on them, have been named quantum nondemolition or back-action evasion observables. In a previous review (Caves {ital et} {ital al}., 1980, Rev. Mod. Phys. {bold 52}, 341) a quantum-mechanical analysis of quantum nondemolition measurements of a harmonic oscillator was presented. The present review summarizes the experimental progress on quantum nondemolition measurements and the classical models developed to describe and guide the development of practical implementations of quantum nondemolition measurements. The relationship between the classical and quantum theoretical models is also reviewed. The concept of quantum nondemolition and back-action evasion measurements originated in the context of measurements on a macroscopic mechanical harmonic oscillator, though these techniques may be useful in other experimental contexts as well, as is discussed in the last part of this review. {copyright} {ital 1996 The American Physical Society.}

Bocko, M.F. [Department of Electrical Engineering, University of Rochester, Rochester, New York 14627 (United States)] [Department of Electrical Engineering, University of Rochester, Rochester, New York 14627 (United States); Onofrio, R. [Dipartimento di Fisica `Galileo Galilei`, Universita di Padova, I-35131 Padova (Italy)] [Dipartimento di Fisica `Galileo Galilei`, Universita di Padova, I-35131 Padova (Italy)

1996-07-01

431

Physical Data Acquisition and Analysis of Possible Flying Extraterrestrial Probes by using Opto-Electronic Devices  

NASA Astrophysics Data System (ADS)

A technical research project regarding the search for evidence of the extraterrestrial origin of UFO phenomena is proposed. After showing the main results from the analysis of an earlier Norwegian instrumental project, specific monitoring techniques and strategies based on magnetometers, radio spectrum analyzers and radar-assisted sensors for the detection and analysis of UFO optical and infrared light are presented together with calculations of exposure times for optical observations. Physical parameters which are expected to be determinable from subsequent data analysis are described in detail. Finally, crucial tests in order to prove or confute a non-natural origin of the UFO phenomenon are proposed and discussed.

Teodorani, M.

2000-02-01

432

Deep Data Analysis of Conductive Phenomena on Complex Oxide Interfaces: Physics from Data Mining  

SciTech Connect

Spatial variability of electronic transport in BiFeO3-CoFe2O4 (BFO-CFO) self-assembled heterostructures is explored using spatially resolved first order reversal curve (FORC) current voltage (IV) mapping. Multivariate statistical analysis of FORC-IV data classifies statistically significant behaviors and maps characteristic responses spatially. In particular, regions of grain, matrix, and grain boundary responses are clearly identified. K-means and Bayesian demixing analysis suggests the characteristic response be separated into four components, with hysteretic type behavior localized at the BFO-CFO tubular interfaces. The conditions under which Bayesian components allow direct physical interpretation are explored, and transport mechanisms at the grain boundaries and individual phases are analyzed. This approach conjoins multivariate statistical analysis with physics-based interpretation, actualizing a robust, universal, data driven approach to problem solving, which can be applied to exploration of local transport and other functional phenomena in other spatially inhomogeneous systems.

Strelcov, Evgheni [ORNL; Belianinov, Alex [ORNL; Hsieh, Ying-Hui [National Chiao Tung University, Hsinchu, Taiwan; Jesse, Stephen [ORNL; Baddorf, Arthur P [ORNL; Chu, Ying Hao [National Chiao Tung University, Hsinchu, Taiwan; Kalinin, Sergei V [ORNL

2014-01-01

433

The Pendulum as a Vehicle for Transitioning from Classical to Quantum Physics: History, Quantum Concepts, and Educational Challenges  

ERIC Educational Resources Information Center

In this article we use the pendulum as the vehicle for discussing the transition from classical to quantum physics. Since student knowledge of the classical pendulum can be generalized to all harmonic oscillators, we propose that a quantum analysis of the pendulum can lead students into the unanticipated consequences of quantum phenomena at the…

Barnes, Marianne B.; Garner, James; Reid, David

2004-01-01

434

Joining the yellow hub: Uses of the Simple Application Messaging Protocol in Space Physics analysis tools  

NASA Astrophysics Data System (ADS)

The interest for data communication between analysis tools in planetary sciences and space physics is illustrated in this paper via several examples of the uses of SAMP. The Simple Application Messaging Protocol is developed in the frame of the IVOA from an earlier protocol called PLASTIC. SAMP enables easy communication and interoperability between astronomy software, stand-alone and web-based; it is now increasingly adopted by the planetary sciences and space physics community. Its attractiveness is based, on one hand, on the use of common file formats for exchange and, on the other hand, on established messaging models. Examples of uses at the CDPP and elsewhere are presented. The CDPP (Centre de Données de la Physique des Plasmas, http://cdpp.eu/), the French data center for plasma physics, is engaged for more than a decade in the archiving and dissemination of data products from space missions and ground observatories. Besides these activities, the CDPP developed services like AMDA (Automated Multi Dataset Analysis, http://amda.cdpp.eu/) which enables in depth analysis of large amount of data through dedicated functionalities such as: visualization, conditional search and cataloging. Besides AMDA, the 3DView (http://3dview.cdpp.eu/) tool provides immersive visualizations and is further developed to include simulation and observational data. These tools and their interactions with each other, notably via SAMP, are presented via science cases of interest to planetary sciences and space physics communities.

Génot, V.; André, N.; Cecconi, B.; Bouchemit, M.; Budnik, E.; Bourrel, N.; Gangloff, M.; Dufourg, N.; Hess, S.; Modolo, R.; Renard, B.; Lormant, N.; Beigbeder, L.; Popescu, D.; Toniutti, J.-P.

2014-11-01

435

An investigation into the spectral analysis of dielectric aging in ferroelectrics.  

PubMed

Aging and degradation indicate the time-dependent change of physical and electrical properties. Most studies neglect to report the effects of aging on the electromechanical properties of an electroactive material and subsequent deterioration of performance. Recent work has shown that the strain and polarization response of an electroactive device can be transformed into its harmonic spectrum (transformation from the time domain to the frequency domain) through the implementation of Fourier analysis. The ability to create this harmonic spectrum provides a new way to characterize the effects of aging by revealing subtle changes in the fundamental components that comprise the response. This study shows how Fourier analysis can be applied to an aged PMN-PT-BT composition to characterize and quantify the effects of aging. The average weak-field permittivity is measured as a function of time, temperature, and frequency. A typical "saddle" in the permittivity and dielectric loss is apparent, and the magnitude decays logarithmically with time. Harmonic analysis of the strain response reveals a slight time-dependent amplitude variation and logarithmic dependence of the phase of the 6th order harmonic. Similar analysis of the polarization response, as a function of time, fully characterizes the development of constriction or wasting seen in a typical aged electrostrictive material. Variations in the amplitudes of the 5th and higher order harmonics of polarization, logarithmic in nature, and the phase of the 5th order harmonic combine to define aging on the harmonic level. PMID:12243584

DiAntonio, Christopher B; Williams, Francis A; Pilgrim, Steven M; Schulze, Walter A

2002-09-01

436

Physical Modeling and Analysis of Seismic Data from a Simulated Fractured Medium  

NASA Astrophysics Data System (ADS)

This thesis studies the physical seismic modeling of a simulated fractured medium to examine variations of seismic reflection amplitudes with source-receiver offset and azimuth (AVAZ). The intent is to extract information about the fracture orientation and magnitude of the anisotropy of a naturally fractured medium. The simulated fractured medium is constructed from phenolic LE-grade material which exhibits orthorhombic symmetry. For initial characterization of the phenolic model, its elastic stiffness coefficients were determined from group velocities. The group velocities along various directions were obtained from three-component physical model transmission data. The phenolic model approximates a weakly anisotropic layer with horizontal transverse isotropy (HTI). Three-dimensional (3D) physical model reflection data were acquired over a model consisting of the simulated fractured layer sandwiched between two isotropic plexiglas layers submerged in water. Interference between primary and ghost events was avoided with a careful 3D seismic survey design. After deterministic amplitude corrections, including a correction for the directivity effect of the physical model transducers, reflection amplitudes agreed with the amplitudes predicted by the Zoeppritz equations, confirming the suitability of the 3D physical model data for a quantitative amplitude analysis. Linear AVAZ inversions for the fracture orientation and HTI anisotropic parameters (including shear-wave splitting parameter) were performed on P-wave reflection amplitudes from the top of the simulated fractured medium. Sensitivity analysis of the inversions results, including variations of the background velocity model and maximum incident angle used, confirms the accuracy of the amplitude analysis. The results reveal that the amplitude analysis of the P-wave data alone allows for extraction the information about the shear-wave anisotropy confined in the P-wave multi-offset and multi-azimuth amplitude data, without any S-measurements.

Mahmoudian, Faranak

437

Sharp bounds for harmonic numbers  

E-print Network

In the paper, we first survey some results on inequalities for bounding harmonic numbers or Euler-Mascheroni constant, and then we establish a new sharp double inequality for bounding harmonic numbers as follows: For $n\\in\\mathbb{N}$, the double inequality -\\frac{1}{12n^2+{2(7-12\\gamma)}/{(2\\gamma-1)}}\\le H(n)-\\ln n-\\frac1{2n}-\\gamma<-\\frac{1}{12n^2+6/5} is valid, with equality in the left-hand side only when $n=1$, where the scalars $\\frac{2(7-12\\gamma)}{2\\gamma-1}$ and $\\frac65$ are the best possible.

Qi, Feng

2010-01-01

438

The Effects of Physical Activity and Physical Fitness on Children's Achievement and Cognitive Outcomes: A Meta-Analysis  

ERIC Educational Resources Information Center

It is common knowledge that physical activity leads to numerous health and psychological benefits. However, the relationship between children's physical activity and academic achievement has been debated in the literature. Some studies have found strong, positive relationships between physical activity and cognitive outcomes, while other studies…

Fedewa, Alicia L.; Ahn, Soyeon

2011-01-01

439

Spectral processing of two concurrent harmonic complexes  

PubMed Central

In a concurrent profile analysis task, each of the two observation intervals was the sum of two harmonic complexes. In the first interval one of the harmonic complexes had a flat spectrum and the other had a broad spectral peak at 1?kHz. In the second interval, the association between the spectral profiles and the complexes was either consistent with the first interval, or inconsistent so that profile changes (flat versus peaked) could be created in both of the complexes. In two experiments, thresholds and psychometric functions for detecting the profile change were measured in terms of the spectral peak’s magnitude as functions of three types of segregation cues: Difference in fundamental frequency, onset asynchrony, and difference in interaural time difference between the two complexes. Decreasing the magnitude of each cue led to higher thresholds, and shallower psychometric functions whose upper asymptotes often failed to reach 100% correct. The patterns of the threshold and psychometric functions varied across cue types and across individual listeners. The results suggest that informational masking is present in the concurrent profile analysis task. Segregation cues appear to contribute to the release from informational masking, but the process depends on listening strategies adopted by individual listeners. PMID:22280600

Shen, Yi; Richards, Virginia M.

2012-01-01

440

Physical therapy treatments for low back pain in children and adolescents: a meta-analysis  

PubMed Central

Background Low back pain (LBP) in adolescents is associated with LBP in later years. In recent years treatments have been administered to adolescents for LBP, but it is not known which physical therapy treatment is the most efficacious. By means of a meta-analysis, the current study investigated the effectiveness of the physical therapy treatments for LBP in children and adolescents. Methods Studies in English, Spanish, French, Italian and Portuguese, and carried out by March 2011, were selected by electronic and manual search. Two independent researchers coded the moderator variables of the studies, and performed the effect size calculations. The mean effect size index used was the standardized mean change between the pretest and posttest, and it was applied separately for each combination of outcome measures, (pain, disability, flexibility, endurance and mental health) and measurement type (self-reports, and clinician assessments). Results Eight articles that met the selection criteria enabled us to define 11 treatment groups and 5 control groups using the group as the unit of analysis. The 16 groups involved a total sample of 334 subjects at the posttest (221 in the treatment groups and 113 in the control groups). For all outcome measures, the average effect size of the treatment groups was statistically and clinically significant, whereas the control groups had negative average effect sizes that were not statistically significant. Conclusions Of all the physical therapy treatments for LBP in children and adolescents, the combination of therapeutic physical conditioning and manual therapy is the most effective. The low number of studies and control groups, and the methodological limitations in this meta-analysis prevent us from drawing definitive conclusions in relation to the efficacy of physical therapy treatments in LBP. PMID:23374375

2013-01-01

441

Network Analysis of Rat Spatial Cognition: Behaviorally-Established Symmetry in a Physically Asymmetrical Environment  

PubMed Central

Background We set out to solve two inherent problems in the study of animal spatial cognition (i) What is a “place”?; and (ii) whether behaviors that are not revealed as differing by one methodology could be revealed as different when analyzed using a different approach. Methodology We applied network analysis to scrutinize spatial behavior of rats tested in either a symmetrical or asymmetrical layout of 4, 8, or 12 objects placed along the perimeter of a round arena. We considered locations as the units of the network (nodes), and passes between locations as the links within the network. Principal Findings While there were only minor activity differences between rats tested in the symmetrical or asymmetrical object layouts, network analysis revealed substantial differences. Viewing ‘location’ as a cluster of stopping coordinates, the key locations (large clusters of stopping coordinates) were at the objects in both layouts with 4 objects. However, in the asymmetrical layout with 4 objects, additional key locations were spaced by the rats between the objects, forming symmetry among the key locations. It was as if the rats had behaviorally imposed symmetry on the physically asymmetrical environment. Based on a previous finding that wayfinding is easier in symmetrical environments, we suggest that when the physical attributes of the environment were not symmetrical, the rats established a symmetric layout of key locations, thereby acquiring a more legible environment despite its complex physical structure. Conclusions and Significance The present study adds a behavioral definition for “location”, a term that so far has been mostly discussed according to its physical attributes or neurobiological correlates (e.g. - place and grid neurons). Moreover, network analysis enabled the assessment of the importance of a location, even when that location did not display any distinctive physical properties. PMID:22815808

Eilam, David; Portugali, Juval; Blumenfeld-Lieberthal, Efrat

2012-01-01

442

arXiv:physics/0306019v12Jun2003 Computing in High Energy and Nuclear Physics, La Jolla, California, March 24 -28, 2003 1 Java Physics Generator and Analysis Modules  

E-print Network

, March 24 - 28, 2003 1 Java Physics Generator and Analysis Modules Michael T. Ronan LBNL, Berkeley, CA event generators are used in defining a common generator interface package. Portable-JNI for TESLA high level OO study tools. Complete physics generation, parallel detector simulations and event

443

Towards a public analysis database for LHC new physics searches using MadAnalysis 5  

E-print Network

We present the implementation, in the MadAnalysis 5 framework, of several ATLAS and CMS searches for supersymmetry in data recorded during the first run of the LHC. We provide extensive details on the validation of our implementations and propose to create a public analysis database within this framework.

B. Dumont; B. Fuks; S. Kraml; S. Bein; G. Chalons; E. Conte; S. Kulkarni; D. Sengupta; C. Wymant

2015-01-27

444

Harmonic algebraic curves and noncrossing partitions  

E-print Network

Motivated by Gauss’s first proof of the fundamental Theorem of Algebra, we study the topology of harmonic algebraic curves. By the maximum principle, a harmonic curve has no bounded components; its topology is determined by the combinatorial data...

Martin, Jeremy L.; Savitt, David; Singer, Ted

2007-02-01

445

An assessment of the harmonic pollution due to line corona  

SciTech Connect

This paper deals with the phenomenon of corona on high voltage overhead transmission lines as a possible source of harmonic pollution. Starting with a validated method for simulating corona by means of distributed nonlinear shunt resistors, the distorted current waveforms for different locations on a long line could be determined. The location-dependent frequency spectrum of the line longitudinal current could be obtained through numerical Fourier analysis. It is shown, that under some operating and weather conditions, the harmonic content of the line current can attain technically unacceptable values.

Saied, M.M.; Oufi, E.A. (Kuwait Univ. (Kuwait))

1993-01-25

446

Optimization study of third harmonic generation in quantum cascade lasers.  

PubMed

A systematic optimization study of quantum cascade lasers with integrated nonlinearity for third-harmonic generation is performed. To model current transport the Pauli master equation is solved using a Monte Carlo approach. A multi-objective particle swarm optimization algorithm is applied to obtain the Pareto front. Our theoretical analysis indicates an optimized structure with five orders of magnitude increase in the generated third-harmonic power with respect to the reference design. This striking performance comes with a low threshold current density of about 1.6 kA/cm2 and is attributed to double resonant phonon scattering assisted extraction and injection scheme of the laser. PMID:25321265

Mojibpour, Ali; Pourfath, Mahdi; Kosina, Hans

2014-08-25

447

The Role of Higher Harmonics In Musical Interval Perception  

NASA Astrophysics Data System (ADS)

Using an alternative parameterization of the roughness curve we make direct use of critical band results to investigate the role of higher harmonics on the perception of tonal consonance. We scale the spectral amplitudes in the complex home tone and complex interval tone to simulate acoustic signals of constant energy. Our analysis reveals that even with a relatively small addition of higher harmonics the perfect fifth emerges as a consonant interval with more, musically important, just intervals emerging as consonant as more and more energy is shifted into higher frequencies.

Krantz, Richard; Douthett, Jack

2011-10-01

448

Accurate, explicit formulae for higher harmonic force spectroscopy by frequency modulation-AFM  

PubMed Central

Summary The nonlinear interaction between an AFM tip and a sample gives rise to oscillations of the cantilever at integral multiples (harmonics) of the fundamental resonance frequency. The higher order harmonics have long been recognized to hold invaluable information on short range interactions but their utilization has thus far been relatively limited due to theoretical and experimental complexities. In particular, existing approximations of the interaction force in terms of higher harmonic amplitudes generally require simultaneous measurements of multiple harmonics to achieve satisfactory accuracy. In the present letter we address the mathematical challenge and derive accurate, explicit formulae for both conservative and dissipative forces in terms of an arbitrary single harmonic. Additionally, we show that in frequency modulation-AFM (FM-AFM) each harmonic carries complete information on the force, obviating the need for multi-harmonic analysis. Finally, we show that higher harmonics may indeed be used to reconstruct short range forces more accurately than the fundamental harmonic when the oscillation amplitude is small compared with the interaction range.

Kuchuk, Kfir

2015-01-01

449

Recent NASA Wake-Vortex Flight Tests, Flow-Physics Database and Wake-Development Analysis  

NASA Technical Reports Server (NTRS)

A series of flight tests over the ocean of a four engine turboprop airplane in the cruise configuration have provided a data set for improved understanding of wake vortex physics and atmospheric interaction. An integrated database has been compiled for wake characterization and validation of wake-vortex computational models. This paper describes the wake-vortex flight tests, the data processing, the database development and access, and results obtained from preliminary wake-characterization analysis using the data sets.

Vicroy, Dan D.; Vijgen, Paul M.; Reimer, Heidi M.; Gallegos, Joey L.; Spalart, Philippe R.

1998-01-01

450

Collection and analysis of Health Physics Research Reactor operational and use data  

SciTech Connect

The Health Physics Research Reactor (HPRR) is the primary research tool at the Dosimetry Applications Research (DOSAR) Facility. In addition to use by the DOSAR staff, the HPRR is used by a wide segment of the scientific community for a variety of experimental purposes. This report is a compilation and analysis of data concerning HPRR uses, users, and operations through the end of FY 1984. 17 refs., 12 tabs.,

Sims, C.S.

1985-04-01

451

Physics and Analysis at a Hadron Collider - Making Measurements (3/3)  

ScienceCinema

This is the third lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This third lecture discusses techniques important for analyses making a measurement (e.g. determining a cross section or a particle property such as its mass or lifetime) using some CDF top-quark analyses as specific examples. The lectures are aimed at graduate students.

None

2011-10-06

452

Application of the combined nonlinear-condensation transformation to problems in statistical analysis and theoretical physics  

NASA Astrophysics Data System (ADS)

We discuss several applications of the recently proposed combined nonlinear-condensation transformation (CNCT) for the evaluation of slowly convergent, nonalternating series. These include certain statistical distributions which are of importance in linguistics, statistical-mechanics theory, and biophysics (statistical analysis of DNA sequences). We also discuss applications of the transformation in experimental mathematics, and we briefly expand on further applications in theoretical physics. Finally, we discuss a related Mathematica program for the computation of Lerch's transcendent.

Aksenov, Sergej V.; Savageau, Michael A.; Jentschura, Ulrich D.; Becher, Jens; Soff, Gerhard; Mohr, Peter J.

2003-01-01

453

Agglomeration, Integration and Tax Harmonization  

Microsoft Academic Search

This Paper considers tax competition and tax harmonization in the presence of agglomeration forces and falling trade costs. With agglomerative forces operating, industry is not indifferent to location in equilibrium, so perfectly mobile capital becomes a quasi-fixed factor. This suggests that the tax game is something subtler than a race to the bottom. Advanced 'core' nations may act like limit-pricing

Richard E. Baldwin; Paul Krugman

2000-01-01

454

Harmonic Phasors and Fourier Series  

NSDL National Science Digital Library

This resource from Johns Hopkins University has audio and interactive components. Various forms of the Fourier series description for periodic signals are based on alternate ways of writing a cosine signal. This resource goes over Phasors, Phasor Sums, Harmonic Phasor Sums, Gibbs Effect, Windowing, Fejer Window, and Hamming Window.

2012-07-13

455

Reduced Harmonic Representation of Partitions  

E-print Network

In the present article the reduced integral representation of partitions in terms of harmonic products has been derived first by using hypergeometry and the new concept of fractional sum and secondly by studying the Fourier series of the kernel function appearing in the integral representation. Using the method of induction, a generalization of the theory has also been obtained.

Michalis Psimopoulos

2011-03-08

456

Strings, standing waves and harmonics  

NSDL National Science Digital Library

This website from the University of New South Wales contains basic information about how stringed instruments produce sound. The site discusses plucked string sound and bowed string sound, standing waves, and harmonics. There are many helpful animations and pictures to illustrate concepts.

Wolfe, Joe

2009-11-16

457

Harmonic filtering for offshore industry  

Microsoft Academic Search

The application of a large number of Adjustable Speed Drives (ASDs) operating Electric Submersible Pumps (ESPs) on two separate offshore platforms, connected to a limited electrical power system on a tanker feeding power to the platforms via subsea power cables, presents technical problems involving high levels of harmonic distortions that experience shows can impact the overall system reliability. Here such

S. J. Merhej; W. H. Nichols

2009-01-01

458

Harmonic undulator radiations with constant magnetic field  

NASA Astrophysics Data System (ADS)

Harmonic undulators has been analysed in the presence of constant magnetic field along the direction of main undulator field. The spectrum modifications in harmonic undulator radiations and intensity degradation as a function of constant magnetic field magnitude at fundamental and third harmonics have been evaluated with a numerical integration method and generalised Bessel function. The role of harmonic field to overcome the intensity reduction due to constant magnetic field and energy spread in electron beam has also been demonstrated.

Jeevakhan, Hussain; Mishra, G.

2015-01-01

459

Harmonic generation from indium-rich plasmas  

SciTech Connect

An experimental study of high-order harmonic generation in In, InSb, InP, and InGaP plasmas using femtosecond laser radiation with variable chirp is presented. Intensity enhancement of the 13th and 21st harmonics compared to the neighboring harmonics by a factor of 200 and 10, respectively, is observed. It is shown that the harmonic spectrum from indium-containing plasma plumes can be considerably modified by controlling the chirp of the driving laser pulse.

Ganeev, R. A.; Kulagin, I. A. [Akadempribor Scientific Association, Academy of Sciences of Uzbekistan, Tashkent 700125 (Uzbekistan); Singhal, H.; Naik, P. A.; Arora, V.; Chakravarty, U.; Chakera, J. A.; Khan, R. A.; Raghuramaiah, M.; Gupta, P. D. [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Redkin, P. V. [Samarkand State University, Samarkand 703004 (Uzbekistan)

2006-12-15

460

Harmonic Morphisms from Homogeneous Spaces -Some Existence Theory -  

E-print Network

Harmonic Morphisms from Homogeneous Spaces - Some Existence Theory - Sigmundur Gudmundsson 2014 #12;Harmonic Morphisms Eigenfamilies - Constructions Orthogonal Harmonic Families - Constructions Low-Dimensional Classifications References Outline 1 Harmonic Morphisms Basics Geometric Motivation

Gudmundsson, Sigmundur

461

Some Physics And System Issues In The Security Analysis Of Quantum Key Distribution Protocols  

E-print Network

In this paper we review a number of issues on the security of quantum key distribution (QKD) protocols that bear directly on the relevant physics or mathematical representation of the QKD cryptosystem. It is shown that the cryptosystem representation itself may miss out many possible attacks which are not accounted for in the security analysis and proofs. Hence the final security claims drawn from such analysis are not reliable, apart from foundational issues about the security criteria that are discussed elsewhere. The cases of continuous-variable QKD and multi-photon sources are elaborated upon.

Horace P. Yuen

2014-05-07

462

Some physics and system issues in the security analysis of quantum key distribution protocols  

NASA Astrophysics Data System (ADS)

In this paper, we review a number of issues on the security of quantum key distribution (QKD) protocols that bear directly on the relevant physics or mathematical representation of the QKD cryptosystem. It is shown that the cryptosystem representation itself may miss out many possible attacks, which are not accounted for in the security analysis and proofs. Hence, the final security claims drawn from such analysis are not reliable, apart from foundational issues about the security criteria that are discussed elsewhere. The cases of continuous-variable QKD and multi-photon sources are elaborated upon.

Yuen, Horace P.

2014-10-01

463

The Local Stellar Velocity Field via Vector Spherical Harmonics  

NASA Technical Reports Server (NTRS)

We analyze the local field of stellar tangential velocities for a sample of 42,339 nonbinary Hipparcos stars with accurate parallaxes, using a vector spherical harmonic formalism.We derive simple relations between the parameters of the classical linear model (Ogorodnikov-Milne) of the local systemic field and low-degree terms of the general vector harmonic decomposition. Taking advantage of these relationships, we determine the solar velocity with respect to the local stars of (V(sub X), V(sub Y), V(sub Z)) = (10.5, 18.5, 7.3) +/- 0.1 km s(exp -1) not for the asymmetric drift with respect to the local standard of rest. If only stars more distant than 100 pc are considered, the peculiar solar motion is (V(sub X), V(sub Y), V(sub Z)) = (9.9, 15.6, 6.9) +/- 0.2 km s(exp -1). The adverse effects of harmonic leakage, which occurs between the reflex solar motion represented by the three electric vector harmonics in the velocity space and higher degree harmonics in the proper-motion space, are eliminated in our analysis by direct subtraction of the reflex solar velocity in its tangential components for each star...

Makarov, V. V.; Murphy, D. W.

2007-01-01

464

Investigation of micro-flaring and secular and quasi-periodic variations in dMe flare stars. IV - Harmonic analysis of YZ Canis Minoris and a possible connection with the Ionson-Mullan hypothesis of coronal heating  

NASA Astrophysics Data System (ADS)

Periodograms of U-band photometric data have been examined to search for "time signatures" in YZ Canis Minoris down to periods of about 6 seconds. Quasi-periods are found at 7.1, 15.4, 33.2 and 92.9 s. From harmonic analysis the fundamental frequencies, 46.3 mHz (21.6s period) and 35.8 mHz (27.9 s) and 10.8 mHz (92.9 s), and several overtones and found. The 7.1-s "time signature" appears to be superposed overtones of these fundamentals. The 15.4-s "time signature" is very close to the 5th overtone of 10.8 mHz. Similarities with other dM4.5e stars, e.g. AT Microscopii (with "time signatures" 13.2 and 7.9 s), may be explicable in terms of a few such close fundamental frequencies. These fundamental frequencies and their overtones may have a bearing on the Ionson-Mullan hypothesis that coronal-heating is coupled to convective motion in late-type stars, and they are important new parameters possibly related to the flaring mechanism.

Andrews, A. D.

1990-03-01

465

Poisson harmonic forms, Kostant harmonic forms, and the S 1 equivariant cohomology of K/T  

E-print Network

Poisson harmonic forms, Kostant harmonic forms, and the S 1 ­equivariant cohomology of K/T Sam Abstract We characterize the harmonic forms on a flag manifold K/T defined by Kostant in 1963 in terms of a Poisson structure. Namely, they are ``Poisson harmonic'' with respect to the so­called Bruhat Poisson

Evens, Sam

466

Investigating student communities with network analysis of interactions in a physics learning center  

NASA Astrophysics Data System (ADS)

Developing a sense of community among students is one of the three pillars of an overall reform effort to increase participation in physics, and the sciences more broadly, at Florida International University. The emergence of a research and learning community, embedded within a course reform effort, has contributed to increased recruitment and retention of physics majors. We utilize social network analysis to quantify interactions in Florida International University’s Physics Learning Center (PLC) that support the development of academic and social integration. The tools of social network analysis allow us to visualize and quantify student interactions and characterize the roles of students within a social network. After providing a brief introduction to social network analysis, we use sequential multiple regression modeling to evaluate factors that contribute to participation in the learning community. Results of the sequential multiple regression indicate that the PLC learning community is an equitable environment as we find that gender and ethnicity are not significant predictors of participation in the PLC. We find that providing students space for collaboration provides a vital element in the formation of a supportive learning community.

Brewe, Eric; Kramer, Laird; Sawtelle, Vashti

2012-06-01

467

Nonlinear analysis of human physical activity patterns in health and disease  

NASA Astrophysics Data System (ADS)

The reliable and objective assessment of chronic disease state has been and still is a very significant challenge in clinical medicine. An essential feature of human behavior related to the health status, the functional capacity, and the quality of life is the physical activity during daily life. A common way to assess physical activity is to measure the quantity of body movement. Since human activity is controlled by various factors both extrinsic and intrinsic to the body, quantitative parameters only provide a partial assessment and do not allow for a clear distinction between normal and abnormal activity. In this paper, we propose a methodology for the analysis of human activity pattern based on the definition of different physical activity time series with the appropriate analysis methods. The temporal pattern of postures, movements, and transitions between postures was quantified using fractal analysis and symbolic dynamics statistics. The derived nonlinear metrics were able to discriminate patterns of daily activity generated from healthy and chronic pain states.

Paraschiv-Ionescu, A.; Buchser, E.; Rutschmann, B.; Aminian, K.

2008-02-01

468

Harmonic maps and isometric embeddings of the spacetime  

E-print Network

We investigate harmonic maps in the context of isometric embeddings when the target space is Ricci-flat and has codimension one. With the help of the Campbell-Magaard theorem we show that any $n$-dimensional ($n\\geqslant 3$) Lorentzian manifold can be isometrically and harmonically embedded in a (n+1)-dimensional semi-Riemannian Ricci-flat space. We then extend our analysis to the case when the target space is an Einstein space. Finally, as an example, we work out the harmonic and isometric embedding of a Friedmann-Robertson-Walker spacetime in a five-dimensional Ricci-flat space and proceed to obtain a general scheme to minimally embed any vacuum solution of general relativity in Ricci-flat spaces with codimension one.

S. Chervon; F. Dahia; C. Romero

2003-12-03

469

Harmonic Balance Computations of Fan Aeroelastic Stability  

NASA Technical Reports Server (NTRS)

A harmonic balance (HB) aeroelastic analysis, which has been recently developed, was used to determine the aeroelastic stability (flutter) characteristics of an experimental fan. To assess the numerical accuracy of this HB aeroelastic analysis, a time-domain aeroelastic analysis was also used to determine the aeroelastic stability characteristics of the same fan. Both of these three-dimensional analysis codes model the unsteady flowfield due to blade vibrations using the Reynolds-averaged Navier-Stokes (RANS) equations. In the HB analysis, the unsteady flow equations are converted to a HB form and solved using a pseudo-time marching method. In the time-domain analysis, the unsteady flow equations are solved using an implicit time-marching approach. Steady and unsteady computations