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1

Lorentz Harmonics, Squeeze Harmonics, and their Physical Applications  

E-print Network

Among the symmetries in physics, the rotation symmetry is most familiar to us. It is known that the spherical harmonics serve useful purposes when the world is rotated. Squeeze transformations are also becoming more prominent in physics, particularly in optical sciences and in high-energy physics. As can be seen from Dirac's light-cone coordinate system, Lorentz boosts are squeeze transformations. Thus the squeeze transformation is one of the fundamental transformations in Einstein's Lorentz-covariant world. It is possible to define a complete set of orthonormal functions defined for one Lorentz frame. It is shown that the same set can be used for other Lorentz frames. Transformation properties are discussed. Physical applications are discussed in both optics and high-energy physics. It is shown that the Lorentz harmonics provide the mathematical basis for squeezed states of light. It is shown also that the same set of harmonics can be used for understanding Lorentz-boosted hadrons in high-energy physics. It is thus possible to transmit physics from one branch of physics to the other branch using the mathematical basis common to them.

Young S. Kim; Marilyn E. Noz

2011-02-19

2

Physics 321 Simple and Damped Harmonic Oscillators  

E-print Network

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

Hart, Gus

3

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

4

Boston University Physics Applets: Simple Harmonic Motion Graphs  

NSDL National Science Digital Library

This web page is an interactive physics simulation that depicts simple harmonic motion graphs. The page gives the equations used for simple harmonic motion and illustrates how acceleration and velocity are derived from position. The applet graphs position, velocity, and acceleration, so the user can see the relations between them. This item is part of a collection of similar simulation-based activities for introductory physics students.

Duffy, Andrew

2008-08-01

5

Fast Analysis\\/Synthesis of Harmonic Signals  

Microsoft Academic Search

Harmonic models are commonly used in signal processing. The analysis of harmonic signals requires the solution of a symmetric Toeplitz system of equations. Levinson-based Toeplitz solvers have a O(n 2) complexity. This paper proposes an O(n) algorithm by encoding the inverse matrices required for the solution of the linear system to a few parameters in order to obtain an approximate

M. Vasilakis; Y. Agiomyrgiannakis; Y. Stylianou

2006-01-01

6

Harmonic analysis of industrial power systems  

SciTech Connect

When large harmonic producing loads are added to an industrial plant power system it is good engineering practice to analyze the impact on the power system by performing harmonic modeling analysis of the system at the design stage. Such a study can identify any potentially harmful resonances or other harmonic levels that are predicted to be in excess of IEEE 519 recommended limits and suggest corrective measures (if necessary). This paper discusses the impact of the harmonic limits of IEEE 519-1992 on the industrial power consumer and addresses the differences between the 1992 and 1981 versions of the standard. Harmonics produced by variable frequency drives are discussed. The data required to conduct a harmonic study, the types of analyses that can be performed, and some of the mitigating measures that can be taken to alleviate a potential harmonic problem are detailed. A case study is presented based on a typical paper mill where a large variable frequency drive was added to the power system.

Ellis, R.G. [Allen-Bradley Canada Ltd., Cambridge, Ontario (Canada)] [Allen-Bradley Canada Ltd., Cambridge, Ontario (Canada)

1996-03-01

7

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

8

Physics of tissue harmonic imaging by ultrasound  

NASA Astrophysics Data System (ADS)

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

Jing, Yuan

9

Elements of Postmodern Harmonic Analysis Hans G. Feichtinger  

E-print Network

Elements of Postmodern Harmonic Analysis Hans G. Feichtinger hans.feichtinger@univie.ac.at October to Postmodern Harmonic Analysis, with strong functional analytic aspects, but also incorporating concepts from

Feichtinger, Hans Georg

10

The Physics Classroom: Standing Waves: Harmonics and Patterns  

NSDL National Science Digital Library

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

2006-10-23

11

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

12

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

13

-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

14

Harmonic measurements and analysis for power factor correction  

SciTech Connect

Nonlinear characteristics of furnace arcs during melting and rolling mill drives generate harmonic currents that can cause system voltage distortion, power loss and an interaction with power factor correction capacitor banks leading to equipment failures. An analytical technique used to correct power factor includes field measurement, system analysis and filter design to reduce harmonic distortion.

Andrews, D. (North Star Steel, Beaumont, TX (United States)); Bishop, M.T.; Witte, J.F. (Cooper Power Systems, Franksville, WI (United States))

1994-04-01

15

Harmonics-causes, effects, measurements, and analysis: an update  

Microsoft Academic Search

Rectification generates harmonic voltages and currents that can cause problems, e.g. insulation failures due to overheating and overvoltages, malfunction of solid-state equipment, communication interference, etc. The common addition of power factor correction capacitors to such a system generally increases the likelihood of such problems occurring. Online data acquisition and analysis of the harmonic content of system voltages and currents may

J. S. McQuilkin

1990-01-01

16

Harmonic Torque Calculation of Induction Motors Using Electromagnetic Field Analysis  

NASA Astrophysics Data System (ADS)

In this paper, we investigate effects of harmonic electromagnetic field to torque characteristics of induction motors from both side of experiment and electromagnetic field analysis. The characteristics of two kinds of the aluminum cage three-phase induction motors are measured and calculated. One is with the closed rotor slots. The other is semi-closed. In the experiment, the negative torque at synchronous speed is measured by driving the induction motor by the synchronous permanent magnet motor. The total torque at load condition is also measured by the torque detector. In the analysis, the harmonic magnetic fields, the harmonic losses and the harmonic torques at each time and space harmonic order are calculated using the nonlinear time-stepping finite element method to clarify the mechanism of the harmonic torque generation. The measured and the calculated results agree well. It is clarified that the negative torque caused by the slot harmonics at the rated load condition is not negligible and that the negative torque is mainly generated by the harmonic core losses.

Yamazaki, Katsumi; Haruishi, Yoshihisa; Ara, Takahiro

17

Aerodynamic analysis of cup anemometers performance: the stationary harmonic response.  

PubMed

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

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

2013-01-01

18

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

19

Spherical harmonic analysis of particle velocity distribution function: Comparison of moments and anisotropies using Cluster data  

NASA Astrophysics Data System (ADS)

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.

Viñas, Adolfo F.; Gurgiolo, Chris

2009-01-01

20

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

21

Iron Loss Analysis of IPM Motor Considering Carrier Harmonics  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the iron loss of interior permanent magnet motors driven by PWM inverters using electromagnetic field analysis. Following 4 methods are applied: (1) Current input finite element method neglecting the carrier harmonics. (2) Voltage input finite element analysis neglecting carrier harmonics. (3) Current input finite element method with the measured armature current waveforms including the carrier harmonics. (4) Voltage input finite element method with the theoretical voltage waveforms of the PWM inverter. The calculated results are compared with the experimental ones. It is clarified that the accuracy of the calculated results are improved by considering the carrier harmonics and that the method (4) can estimate the iron loss of the IPM motor accurately before manufacturing. The variation of the iron loss components due to the driving condition is also clarified.

Yamazaki, Katsumi; Seto, Yoshiaki; Tanida, Makoto

22

PHYSICAL REVIEW A 84, 053404 (2011) Influence of gas pressure on high-order-harmonic generation of Ar and Ne  

E-print Network

PHYSICAL REVIEW A 84, 053404 (2011) Influence of gas pressure on high-order-harmonic generation study the effect of gas pressure on the generation of high-order harmonics where harmonics due, 42.65.Ky I. INTRODUCTION In the last two decades, high-order-harmonic generation (HHG) has been

Le, Anh-Thu

23

Harmonic measurements and analysis for power factor correction  

SciTech Connect

Maximizing electric power transfer directly effects the productivity of an electric arc furnace operation. Arc furnaces and rolling mill loads operate at power factors that result in penalty charges and lower bus voltages. In addition, the nonlinear characteristics of the furnace arcs and rolling mill drives generate significant harmonic currents that flow through the plant and utility power system. These harmonic currents cause system voltage distortions, power loss in the system, and can interact with power factor correction capacitor banks leading to equipment failures. This paper presents the analytical technique used to correct power factor in a modern steel manufacturing facility. The study included field measurements, harmonic analysis, and filter design work to reduce the amount of harmonic distortion in the plant. The modeling of arc furnaces and rolling mills for a harmonic analysis study is also discussed. The solution recommended in this paper to increase power factor and reduce harmonics can be applied to other steel manufacturing facilities to improve power quality and therefore plant productivity.

Witte, J.F.; Bishop, M.T. (Cooper Power Systems, Franksville, WI (United States)); Andrews, D. (North Star Steel Texas, Inc., Beaumont, TX (United States))

1993-07-01

24

Asymptotic spectrum of the oblate spin-weighted spheroidal harmonics: A WKB analysis  

NASA Astrophysics Data System (ADS)

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

Hod, Shahar

2012-10-01

25

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

26

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

27

Harmonic Torque Calculation of Induction Motors Using Electromagnetic Field Analysis  

Microsoft Academic Search

In this paper, we investigate effects of harmonic electromagnetic field to torque characteristics of induction motors from both side of experiment and electromagnetic field analysis. The characteristics of two kinds of the aluminum cage three-phase induction motors are measured and calculated. One is with the closed rotor slots. The other is semi-closed. In the experiment, the negative torque at synchronous

Katsumi Yamazaki; Yoshihisa Haruishi; Takahiro Ara

2004-01-01

28

A practical method of harmonic analysis for power converter  

Microsoft Academic Search

The converter is one important harmonic source in power systems. For the knowledge of harmonic characteristics of a converter, it is very important to evaluate the harmonic situations of AC and DC sides, and also it is very helpful to design the harmonic filters and to suppress harmonic propagation. A practical method of harmonic evaluation for a power converter is

Jianguo Jiang; Weimin Xie; Juan Zhou

2000-01-01

29

The influence of spring length on the physical parameters of simple harmonic motion  

NASA Astrophysics Data System (ADS)

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 k, the angular frequency ? and the damping factor ? of the oscillations. To characterize the behaviour of these variables we worked with a series of springs of seven different lengths, in which the elastic constant was found by means of the spring-elongation measurement and ? was obtained from the measurement of the oscillation period T of a suspended mass. The oscillatory movement was recorded using a force sensor and the ? value was determined by the fit of the envelope oscillations. Graphical analysis of the results shows that k, ? and ? decrease when the natural spring length increases. This experiment can be performed with equipment normally found in undergraduate physics laboratories. In addition, through graphical analysis students can deduce some relationships between variables that determine the simple harmonic motion behaviour.

Triana, C. A.; Fajardo, F.

2012-01-01

30

Equivalence of curvature and noncommutativity in a physical space: Harmonic oscillator on sphere  

NASA Astrophysics Data System (ADS)

We study the two-dimensional harmonic oscillator on a noncommutative plane. We show that by introducing appropriate Bopp shifts, one can obtain the Hamiltonian of a two-dimensional harmonic oscillator on a sphere according to the Higgs model. By calculating the commutation relations, we show that this noncommutativity is strictly dependent on the curvature of the background space. In other words, we introduce a kind of duality between noncommutativity and curvature by introducing noncommutativity parameters as functions of curvature. Also, it is shown that the physical realization of such model is a charged harmonic oscillator in the presence of electromagnetic field.

Ghorashi, S. A. A.; Mahdifar, A.; Roknizadeh, R.

2014-06-01

31

Harmonic Analysis for Optically Modulating Bodies Using the Harmonic Structure Function  

NASA Astrophysics Data System (ADS)

Lockheed Martin Hawaii presents a novel signal processing algorithm for focal plane array processing. We introduce the Harmonic Structure Function (HSF) and demonstrate its capability in detecting, classifying and counting rotating bodies in a single pixel. The HSF has a powerful use in dynamical situations occurring on scales less than the single pixel solid angle. The work presented here is making a major impact in the Missile Defense Agency's Project Hercules Forward Based Sensor (FBS) group but the results presented here is shown in an unclassified form. First, the HSF algorithm is detailed. The origin of the HSF is in the ASW (AntiSubmarine Warfare) acoustic processing domain and the analogy to the focal plane is given. Next, the mathematical definition of the HSF and the natural extension from integral to discrete form is detailed. Thereafter, additional harmonic processing techniques such as the so-called 'sidelobe' reduction are explained. These techniques are powerful methods to determine the fundamental frequency of a given rotating body that can have various harmonically related narrow band tonal structures. Simulations of rotating bodies and modulating reflectance used for analysis are then discussed. These simulations result in the construction of time series data for rotating bodies with fundamental frequencies in noisy backgrounds. The HSF is then used to analyze these fidelity simulations. It is shown that the HSF is capable of detecting, classifying and countingobjects on a single pixel. Finally, the robustness of the algorithm is analyzed and it is shown that the number of detectable objects is dependent on sample rate, target temporal extent, and other factors. This analysis yield important considerations for sensor developers and operators.

Dikeman, R. D.; Lin, S.; Kim, C.

32

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

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

33

Mesoscale harmonic analysis of homogenous dislocation nucleation  

E-print Network

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

Asad Hasan; Craig E. Maloney

2012-05-08

34

Harmonic analysis with respect to heat kernel measure  

Microsoft Academic Search

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

Brian C. Hall

2000-01-01

35

Improving AFM images with harmonic interference by spectral analysis.  

PubMed

Atomic force microscopy (AFM) is one of the most sensitive tools for nanoscale imaging. As such, it is very sensitive to external noise sources that can affect the quality of collected data. The intensity of the disturbance depends on the noise source and the mode of operation. In some cases, the internal noise from commercial AFM controllers can be significant and difficult to remove. Thus, a new method based on spectrum analysis of the scanned images is proposed to reduce harmonic disturbances. The proposal is a post-processing method and can be applied at any time after measurements. This article includes a few methods of harmonic cancellation (e.g., median filtering, wavelet denoising, Savitzky-Golay smoothing) and compares their effectiveness. The proposed method, based on Fourier transform of the scanned images, was more productive than the other methods mentioned before. The presented data were achieved for images of conductive layers taken in a contact AFM mode. PMID:22214544

Kiwilszo, Marek; Zieli?ski, Artur; Smulko, Janusz; Darowicki, Kazimierz

2012-02-01

36

Boston University Physics Applets: Simple Harmonic Motion and Uniform Circular Motion  

NSDL National Science Digital Library

This web page is an interactive Java simulation that illustrates the correlation between simple harmonic motion and uniform circular motion. The page describes the conditions in which this is true, and shows graphically that their motion in the x direction is identical. This item is part of a collection of similar simulation-based activities designed for introductory physics students.

Duffy, Andrew

2008-08-01

37

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

38

IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 32, NO. 3, JUNE 2004 1073 On the Physics of Harmonic Injection  

E-print Network

IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 32, NO. 3, JUNE 2004 1073 On the Physics of Harmonic, and Ian Dobson, Senior Member, IEEE Abstract--The physics of signal injection to shape the output spectrum

Dobson, Ian

39

On-screen synthesis and analysis of harmonics: a student-oriented package  

Microsoft Academic Search

The implementation of an interactive approach to the display and manipulation of power system harmonics is described. The resulting microcomputer program, which was developed primarily for educational use within the electrical engineering curriculum, allows both synthesis of waves from harmonic (sinusoidal) components and analysis of specified periodic waveforms in terms of their harmonic content. Data may be interactively modified, and

Howard A. Smolleck; Dane S. Dwyer; Laura M. Rust

1995-01-01

40

Harmonic Analysis of Rail Transportation Systems with Probabilistic Techniques  

Microsoft Academic Search

Harmonics in rail transportation systems are an important design aspect. The overall load in these systems consists of a few large traction motors, often supplied by thyristor controlled choppers or PWM converters. These converters produce high levels of harmonic currents, which may extend into the kHz range. Recognizing harmonic problems in an early stage of development is important in order

J. van Casteren; F. Groeman

2006-01-01

41

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

42

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

43

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

E-print Network

Harmonic Analysis of a Three-Phase Diode Bridge Rectifier based on Sampled-Data Model K. L. Lian presents a time domain method to analyze the three phase rectifier with capacitor output filter Rectifier, Harmonics, Continuous Conduction Mode, Discontinuous Conduction Mode, Steady State Analysis. I

Lehn, Peter W.

44

Elements of harmonic analysis related to the third basic zero order Bessel function  

NASA Astrophysics Data System (ADS)

This paper is devoted to the study of some q-harmonic analysis related to the third q-Bessel function of order zero. We establish a product formula leading to a q-translation with some positive kernel. As an application, we provide a q-analogue of the continuous wavelet transform related to this harmonic analysis.

Bettaibi, Néji; Bouzeffour, Fethi; Ben Elmonser, Hédi; Binous, Wafa

2008-06-01

45

The use of computer algebra in the harmonic analysis of phase controlled waveforms  

Microsoft Academic Search

Engineers and scientists wishing to perform harmonic analysis of waveforms may need to use discrete methods in preference to analytical methods partly because of the volume of algebra in analytical methods. Powerful computer algebra (in this study MAPLE) now offers a new mathematical environment which permits the investigation of analytical methods in harmonic analysis. MAPLE procedures are developed to investigate

A. D. Rough; J. Richardson

1992-01-01

46

Harmonic-Resonance Analysis in a Maglev Feeding System  

Microsoft Academic Search

A feeding circuit for a superconducting magnetic levitation train system, or the so-called ``maglev'' consists of feeder cables and armature coils which show characteristics of a distributed-parameter line. Electric power is supplied to the cables and coils by PWM inverters whose output voltage contains a large amount of harmonics. As a result, a harmonic resonance may occur in the feeding

Hidenori Shigeeda; Akinobu Okui; Hirofumi Akagi

2006-01-01

47

The ionospheric Sq current system obtained by spherical harmonic analysis  

NASA Astrophysics Data System (ADS)

An earlier comprehensive analysis of geomagnetic tides by Winch is revisited to display changes in the current systems with season and longitude. The data used come from the quiet Sun years 1964-1965. We choose to present some total equivalent current systems, being the sum of the external and internal parts derived in the spherical harmonic analysis. The latitudes and local times of the current system foci are generally in agreement with other workers. The amplitudes of the current system vortices follow an annual variation with maximum in summer. The longitude variations of the vortex amplitudes vary as the inverse of the magnetic field strength at both equinoxes but have different variations at the solstices. Other longitude maxima which have been reported in the equatorial electrojet intensity were not found. We examine in detail the "invasions" of the summer current systems across the equator, identifying these as signatures of field-aligned currents (FACs). The tilting of current contours with respect to the equator is interpreted as being due to midday FACs. As others have found, the identification of afternoon FACs is more difficult. The seasonal swap-over of FAC directions occurs not in September but in October-November.

Stening, R. J.; Winch, D. E.

2013-03-01

48

Repeat analysis and incurred sample reanalysis: recommendation for best practices and harmonization from the global bioanalysis consortium harmonization team.  

PubMed

The A7 harmonization team (A7 HT), a part of the Global Bioanalysis Consortium (GBC), focused on reviewing best practices for repeat analysis and incurred sample reanalysis (ISR) as applied during regulated bioanalysis. With international representation from Europe, Latin America, North America, and the Asia Pacific region, the team first collated common practices and guidance recommendations and assessed their suitability from both a scientific and logistical perspective. Subsequently, team members developed best practice recommendations and refined them through discussions and presentations with industry experts at scientific meetings. This review summarizes the team findings and best practice recommendations. The few topics where no consensus could be reached are also discussed. The A7 HT recommendations, together with those from the other GBC teams, provide the basis for future international harmonization of regulated bioanalytical practices. PMID:25135836

Fluhler, Eric; Vazvaei, Faye; Singhal, Puran; Vinck, Petra; Li, Wenkui; Bhatt, Jignesh; de Boer, Theo; Chaudhary, Ajai; Tangiuchi, Masahiro; Rezende, Vinicius; Zhong, Dafang

2014-11-01

49

Analysis of Harmonics in Power Systems Using the Wavelet Packet Transform  

Microsoft Academic Search

The paper proposes an algorithm based on the wavelet-packet transform for the analysis of harmonics in power systems. The algorithm proposed decomposes the voltage\\/current waveforms into uniform frequency bands corresponding to the odd harmonic components of the signal. First, the selection of the mother wavelet, the sampling frequency and the frequency characteristics of the selected wavelet filter bank are studied.

Julio Barros; Ramón I. Diego

2005-01-01

50

Harmonic-Resonance Analysis in a Maglev Feeding System  

NASA Astrophysics Data System (ADS)

A feeding circuit for a superconducting magnetic levitation train system, or the so-called “maglev” consists of feeder cables and armature coils which show characteristics of a distributed-parameter line. Electric power is supplied to the cables and coils by PWM inverters whose output voltage contains a large amount of harmonics. As a result, a harmonic resonance may occur in the feeding circuit. Besides the above characteristics, the connecting point of sections (groups of armature coils) or the feeder cables length changes according to the movement of a maglev train, thus causing changes in the harmonic-resonance characteristics of the feeding circuit. This paper describes analytical results of the harmonic resonance in the feeding circuit for the maglev, with the focus on changes in the connecting point of sections and the feeder cables length.

Shigeeda, Hidenori; Okui, Akinobu; Akagi, Hirofumi

51

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.

52

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

53

Analysis of cyclotron harmonic emissions at the outer planets  

NASA Technical Reports Server (NTRS)

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

Roth, I.; Hudson, M. K.

1992-01-01

54

A Computer Algebra Toolbox for Harmonic Sums Related to Particle Physics  

E-print Network

In this work we present the computer algebra package HarmonicSums and its theoretical background for the manipulation of harmonic sums and some related quantities as for example Euler-Zagier sums and harmonic polylogarithms. Harmonic sums and generalized harmonic sums emerge as special cases of so-called d'Alembertian solutions of recurrence relations. We show that harmonic sums form a quasi-shuffle algebra and describe a method how we can find algebraically independent harmonic sums. In addition, we define a differentiation on harmonic sums via an extended version of the Mellin transform. Along with that, new relations between harmonic sums will arise. Furthermore, we present an algorithm which rewrites certain types of nested sums into expressions in terms of harmonic sums. We illustrate by nontrivial examples how these algorithms in cooperation with the summation package Sigma support the evaluation of Feynman integrals.

Jakob Ablinger

2010-11-04

55

Analysis of biochemical phase shift oscillators by a harmonic balancing technique.  

PubMed

The use of harmonic balancing techniques for theoretically investigating a large class of biochemical phase shift oscillators is outlined and the accuracy of this approximate technique for large dimension nonlinear chemical systems is considered. It is concluded that for the equations under study these techniques can be successfully employed to both find periodic solutions and to indicate those cases which can not oscillate. The technique is a general one and it is possible to state a step by step procedure for its application. It has a substantial advantage in producing results which are immediately valid for arbitrary dimension. As the accuracy of the method increases with dimension, it complements classical small dimension methods. The results obtained by harmonic balancing analysis are compared with those obtained by studying the local stability properties of the singular points of the differential equation. A general theorem is derived which identifies those special cases where the results of first order harmonic balancing are identical to those of local stability analysis, and a necessary condition for this equivalence is derived. As a concrete example, the n-dimensional Goodwin oscillator is considered where p, the Hill coefficient of the feedback metabolite, is equal to three and four. It is shown that for p = 3 or 4 and n less than or equal to 4 the approximation indicates that it is impossible to construct a set of physically permissible reaction constants such that the system possesses a periodic solution. However for n greater than or equal to 5 it is always possible to find a large domain in the reaction constant space giving stable oscillations. A means of constructing such a parameter set is given. The results obtained here are compared with previously derived results for p = 1 and p = 2. PMID:1022832

Rapp, P

1976-11-25

56

Brownian Motion and Harmonic Analysis on Sierpinski Carpets  

Microsoft Academic Search

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

Martin T. Barlow; Richard F. Bass

1999-01-01

57

Spherical harmonic analysis of wavefields using multiple circular sensor arrays  

E-print Network

-spherical microphone array structure, with increased flexibility, for allowable sensor locations in order to perform provides an alternative design to the traditional spherical microphone arrays with increased flexibility harmonic decomposition array using 57 microphones to operate over a frequency band of an octave and compare

Abhayapala, Thushara D.

58

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

59

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-color laser fields. Such supercontinuum harmonics can be superposed to generate an isolated sub-30- attosecond of macroscopic propagation on the supercontinuum harmonic spectra and the subsequent attosecond-pulse generation

Chu, Shih-I

60

A new frequency domain arc furnace model for iterative harmonic analysis  

SciTech Connect

This paper presents a new frequency domain Arc Furnace model for Iterative Harmonic Analysis (IHA) by means of a Newton method. Powerful analytical expressions for harmonic currents and their derivatives are obtained under the balanced conditions of the system. The model offers a three phase configuration where there is no path for homopolar currents. Moreover, it contemplates continuous and discontinuous evolution of the arc current. The solution obtained is validated by means of time domain simulations. Finally, the model was integrated in a harmonic power flow where studies have been performed in a network with more than 700 busbars and 7 actual Arc Furnace Loads.

Mayordomo, J.G.; Beites, L.F.; Asensi, R.; Izzeddine, M. [Univ. Politecnica de Madrid (Spain). Escuela Tecnica Superior de Ingenieros Industriales] [Univ. Politecnica de Madrid (Spain). Escuela Tecnica Superior de Ingenieros Industriales; Zabala, L.; Amantegui, J. [Iberdrola S.A., Bilbao (Spain)] [Iberdrola S.A., Bilbao (Spain)

1997-10-01

61

Completion report harmonic analysis of electrical distribution systems  

SciTech Connect

Harmonic currents have increased dramatically in electrical distribution systems in the last few years due to the growth in non-linear loads found in most electronic devices. Because electrical systems have been designed for linear voltage and current waveforms; (i.e. nearly sinusoidal), non-linear loads can cause serious problems such as overheating conductors or transformers, capacitor failures, inadvertent circuit breaker tripping, or malfunction of electronic equipment. The U.S. Army Center for Public Works has proposed a study to determine what devices are best for reducing or eliminating the effects of harmonics on power systems typical of those existing in their Command, Control, Communication and Intelligence (C3I) sites.

Tolbert, L.M.

1996-03-01

62

Multichannel continuous harmonic analysis in real-time  

SciTech Connect

In this paper a flexible, modular multichannel continuous real-time harmonic analyzer with the capability of precision time stamping (via GPS satellite signals) of the acquired data is described. The key design features which provide this performance are fully discussed. These include remote distributed data conversion modules coupled via digital fibre optic links to parallel individual digital signal processor Multibus II based modules which are all controlled by a highly integrated 486 based module. The resultant Multibus II parallel processor system is run under the iRMXIII real-time operating system and is interfaced via ethernet to control and display workstations using a custom designed Windows 3 environment. The ready extension of the harmonic monitoring system to transient measurement is also described.

Miller, A.J.V.; Dewe, M.B. (Canterbury Museum, Christchurch (New Zealand))

1992-10-01

63

Multiple-frequency three-phase load flow for harmonic analysis  

Microsoft Academic Search

A multiple-frequency three-phase load-flow model was developed in this paper. There are two new submodels including the fundamental power flow (FPF) and harmonic frequency power-flow (HPF) model. In FPF, models of electrical elements and PV buses were treated in the form of current injections in a transmission system. The standard Fourier analysis was used to deal with the harmonic loads

Whei-Min Lin; Tung-Sheng Zhan; Ming-Tong Tsay

2004-01-01

64

High-precision harmonic magnetic-field measurement and analysis using a fixed angle Hall probe  

Microsoft Academic Search

A special theoretical concept involving the harmonic magnetic-field measurement and analysis method using a fixed angle Hall probe was developed at the Synchrotron Radiation Research Center (SRRC) for measuring as well as analyzing the triple bending achromat magnets of the storage ring. The method can be used to simulate the harmonic magnetic-field calculation of the two-dimensional (2D) ‘‘magnet’’ program. This

C. S. Hwang; F. Y. Lin; T. H. Huang; G. J. Jan; P. K. Tseng

1994-01-01

65

Physical Culture, Physical Education and Relational Analysis  

Microsoft Academic Search

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

David Kirk

1999-01-01

66

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

67

Physical pendulum experiments to enhance the understanding of moments of inertia and simple harmonic motion  

NASA Astrophysics Data System (ADS)

This paper describes a set of experiments aimed at overcoming some of the difficulties experienced by students learning about the topics of moments of inertia and simple harmonic motion, both of which are often perceived to be complex topics amongst students during their first-year university courses. By combining both subjects in a discussion about physical pendula, in which the oscillation time periods for the periodic motion of several objects (a tennis ball, a thin beam, a hoop and a solid disc) are measured and compared, students are able to understand both topics at a higher level and also experience the synergistic effect of combining two or more physics themes in order to accelerate their learning whilst simultaneously raising their motivation. Special attention is given to the ‘ball and stick’ pendulum in which a block of material (treated as a point mass) can be moved along a shaft to create a composite pendulum whose time period exhibits a minimum value at a certain separation between the block and the rotation axis.

Richardson, Tim H.; Brittle, Stuart A.

2012-09-01

68

Spherical harmonic analysis of cortical complexity in autism and dyslexia  

PubMed Central

Alterations in gyral form and complexity have been consistently noted in both autism and dyslexia. In this present study, we apply spherical harmonics, an established technique which we have exapted to estimate surface complexity of the brain, in order to identify abnormalities in gyrification between autistics, dyslexics, and controls. On the order of absolute surface complexity, autism exhibits the most extreme phenotype, controls occupy the intermediate ranges, and dyslexics exhibit lesser surface complexity. Here, we synthesize our findings which demarcate these three groups and review how factors controlling neocortical proliferation and neuronal migration may lead to these distinctive phenotypes. PMID:22545198

Williams, Emily L.; El-Baz, Ayman; Nitzken, Matthew; Switala, Andrew E.; Casanova, Manuel F.

2012-01-01

69

Harmonic measurements, analysis, and power factor correction in a modern steel manufacturing facility  

SciTech Connect

Maximizing electric power transfer directly affects the productivity of an electric arc furnace operation. Arc furnaces and rolling mill loads operate at power factors that result in penalty charges and lower bus voltages. In addition, the nonlinear characteristics of the furnace arcs and rolling mill drives generate significant harmonic currents that flow through the plant and utility power system. These harmonic currents cause system voltage distortion and power loss in the system, and can interact with power factor correction capacitor banks leading to equipment failures. This paper presents the analytical technique used to correct power factor in a modern steel manufacturing facility. The study included field measurements, harmonic analysis, and filter design work to reduce the amount of harmonic distortion in the plant. The modeling of arc furnaces and rolling mills for a harmonic analysis study is also discussed. The solutions recommended in this paper to increase power factor and reduce harmonics can be applied to other steel manufacturing facilities to improve power quality and therefore plant productivity.

Andrews, D. [North Star Steel, Beaumont, TX (United States). Dept. of Plant Engineering] [North Star Steel, Beaumont, TX (United States). Dept. of Plant Engineering; Bishop, M.T.; Witte, J.F. [Cooper Power Systems, Franksville, WI (United States). Systems Engineering Group] [Cooper Power Systems, Franksville, WI (United States). Systems Engineering Group

1996-05-01

70

Physics analysis tools  

SciTech Connect

There are many tools used in analysis in High Energy Physics (HEP). They range from low level tools such as a programming language to high level such as a detector simulation package. This paper will discuss some aspects of these tools that are directly associated with the process of analyzing HEP data. Physics analysis tools cover the whole range from the simulation of the interactions of particles to the display and fitting of statistical data. For purposes of this paper, the stages of analysis is broken down to five main stages. The categories are also classified as areas of generation, reconstruction, and analysis. Different detector groups use different terms for these stages thus it is useful to define what is meant by them in this paper. The particle generation stage is a simulation of the initial interaction, the production of particles, and the decay of the short lived particles. The detector simulation stage simulates the behavior of an event in a detector. The track reconstruction stage does pattern recognition on the measured or simulated space points, calorimeter information, etc., and reconstructs track segments of the original event. The event reconstruction stage takes the reconstructed tracks, along with particle identification information and assigns masses to produce 4-vectors. Finally the display and fit stage displays statistical data accumulated in the preceding stages in the form of histograms, scatter plots, etc. The remainder of this paper will consider what analysis tools are available today, and what one might expect in the future. In each stage, the integration of the tools with other stages and the portability of the tool will be analyzed.

Kunz, P.F.

1991-04-01

71

PARSHL: An Analysis/Synthesis Program for Non-Harmonic Sounds Based on a Sinusoidal Representation  

E-print Network

. With these techniques, the signal is modeled as a sum of sine waves, and the parameters to be determined by analysis are the slowly time-varying amplitude and frequency for each sine wave. In the following subsections, wePARSHL: An Analysis/Synthesis Program for Non-Harmonic Sounds Based on a Sinusoidal Representation

Smith III, Julius Orion

72

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

ERIC Educational Resources Information Center

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

Macomber, Hilliard K.

1981-01-01

73

Analysis of astrometric catalogues with vector spherical harmonics  

E-print Network

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

Francois Mignard; Sergei Klioner

2012-06-29

74

Second harmonic generation imaging and Fourier transform spectral analysis reveal damage in fatigue-loaded tendons.  

PubMed

Conventional histologic methods provide valuable information regarding the physical nature of damage in fatigue-loaded tendons, limited to thin, two-dimensional sections. We introduce an imaging method that characterizes tendon microstructure three-dimensionally and develop quantitative, spatial measures of damage formation within tendons. Rat patellar tendons were fatigue loaded in vivo to low, moderate, and high damage levels. Tendon microstructure was characterized using multiphoton microscopy by capturing second harmonic generation signals. Image stacks were analyzed using Fourier transform-derived computations to assess frequency-based properties of damage. Results showed 3D microstructure with progressively increased density and variety of damage patterns, characterized by kinked deformations at low, fiber dissociation at moderate, and fiber thinning and out-of-plane discontinuities at high damage levels. Image analysis generated radial distributions of power spectral gradients, establishing a "fingerprint" of tendon damage. Additionally, matrix damage was mapped using local, discretized orientation vectors. The frequency distribution of vector angles, a measure of damage content, differed from one damage level to the next. This study established an objective 3D imaging and analysis method for tendon microstructure, which characterizes directionality and anisotropy of the tendon microstructure and quantitative measures of damage that will advance investigations of the microstructural basis of degradation that precedes overuse injuries. PMID:20232150

Fung, David T; Sereysky, Jedd B; Basta-Pljakic, Jelena; Laudier, Damien M; Huq, Rumana; Jepsen, Karl J; Schaffler, Mitchell B; Flatow, Evan L

2010-05-01

75

On the use of maximum entropy/autoregressive spectrum in harmonic analysis of time series  

NASA Astrophysics Data System (ADS)

The maximum entropy (ME) spectrum, or its equivalent form of the autoregressive (AR) spectrum, has been used as a tool for harmonic analysis of time series in geophysics. This paper critically examines its usage in estimating the amplitude and the exponential decay rate of a harmonic function. The argument is based upon Prony's relation, which relates a complex-conjugate pair of poles for the AR model of the time series on one hand, to the complex frequency of one harmonic component in the time series on the other. It is found that: (i) the ME spectrum can be used as an estimator for the decay rate in a way similar to the Fourier spectral analysis; (ii) the ME spectrum contains no information whatsoever about the amplitude, contrary to what has been claimed and practiced in geophysical applications.

Fong Chao, B.

1990-09-01

76

Weighted Hardy-Littlewood Theorems for Conjugate A-Harmonic Tensors  

NASA Astrophysics Data System (ADS)

In this paper, we establish some versions of A( ? 1( x), ? 2( x), ?, ?)-weighted Hardy-Littlewood inequalities for conjugate A-harmonic tensors, the theory of harmonic analysis and A-harmonic differential forms largely pertain to applications in mathematical physics, quantum field theory, elementary particle physics, etc.

Wen, Haiyu

2014-11-01

77

Automated cardiac sarcomere analysis from second harmonic generation images.  

PubMed

Automatic quantification of cardiac muscle properties in tissue sections might provide important information related to different types of diseases. Second harmonic generation (SHG) imaging provides a stain-free microscopy approach to image cardiac fibers that, combined with our methodology of the automated measurement of the ultrastructure of muscle fibers, computes a reliable set of quantitative image features (sarcomere length, A-band length, thick-thin interaction length, and fiber orientation). We evaluated the performance of our methodology in computer-generated muscle fibers modeling some artifacts that are present during the image acquisition. Then, we also evaluated it by comparing it to manual measurements in SHG images from cardiac tissue of fetal and adult rabbits. The results showed a good performance of our methodology at high signal-to-noise ratio of 20 dB. We conclude that our automated measurements enable reliable characterization of cardiac fiber tissues to systematically study cardiac tissue in a wide range of conditions. PMID:24853145

Garcia-Canadilla, Patricia; Gonzalez-Tendero, Anna; Iruretagoyena, Igor; Crispi, Fatima; Torre, Iratxe; Amat-Roldan, Ivan; Bijnens, Bart H; Gratacos, Eduard

2014-05-01

78

PHYSICAL REVIEW B 83, 165438 (2011) Saturation of the second harmonic generation from GaAs-filled metallic hole arrays  

E-print Network

with a large (2) ((2) = 2d), for example, d14 (GaAs) 5 Ã? d33 (LiNbO3) = 94 pm/V (near 4 m) (Ref. 15) that havePHYSICAL REVIEW B 83, 165438 (2011) Saturation of the second harmonic generation from Ga-Bahae,2 and S. R. J. Brueck1,* 1 Center for High Technology Materials and Department of Electrical

Sheik-Bahae, Mansoor

79

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

80

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

E-print Network

NON-SPHERICAL MICROPHONE ARRAY STRUCTURES FOR 3D BEAMFORMING AND SPHERICAL HARMONIC ANALYSIS signal processing. This paper shows how to design non-spherical microphone array structures in 3D space functions over circles to construct an array of parallel circles of microphones. The result provides

Abhayapala, Thushara D.

81

Use of harmonic inversion techniques in semiclassical quantization and analysis of quantum spectra  

Microsoft Academic Search

Harmonic inversion is introduced as a powerful tool for both the analysis of quantum spectra and semiclassical periodic orbit quantization. The method allows one to circumvent the uncertainty principle of the conventional Fourier transform and to extract dynamical information from quantum spectra which has been unattainable before, such as bifurcations of orbits, the uncovering of hidden ghost orbits in complex

Jörg Main

1999-01-01

82

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

83

Magnetic measurement system for harmonic analysis of LBL SSC (Superconducting Super Collider) model dipoles and quadrupoles  

SciTech Connect

Specialized hardware and software have been developed to facilitate harmonic error analysis measurements of one-meter-long Superconducting Super Collider (SSC) model dipole and quadrupole magnets. Cold bore measurements feature cryogenic search-coil arrays with high bucking ratios that also have sufficient sensitivity to make room-temperature measurements at the low magnet currents of approx.10 A. Three sets of search coils allow measurements of the center, either end, and/or the axially integrated field. Signals from the search coils are digitally integrated by means of a voltage-to-frequency converter feeding an up-down counter. The data are drift corrected, Fourier analyzed, converted to physical quantities, and printed and plotted. A cycle of measurements including data acquisition, processing, and the generation of tabular and graphic output requires 80 seconds. The vast amount of data generated (several hundred measurement cycles for each magnet) has led to the development of postprocessing programs and procedures. Spreadsheets allow easy manipulation and comparison of results within a test series and between magnets. 8 refs., 4 figs., 1 tab.

Green, M.I.; Barale, P.J.; Gilbert, W.S.; Hassenzahl, W.V.; Nelson, D.H.; Taylor, C.E.; Travis, N.J.; Van Dyke, D.A.

1987-09-01

84

Analysis of crystallographic texture information by the hyperspherical harmonic expansion  

E-print Network

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

Mason, Jeremy K. (Jeremy Kyle)

2009-01-01

85

Workshop on Harmonic Oscillators  

NASA Technical Reports Server (NTRS)

Proceedings of a workshop on Harmonic Oscillators held at the College Park Campus of the University of Maryland on March 25 - 28, 1992 are presented. The harmonic oscillator formalism is playing an important role in many branches of physics. This is the simplest mathematical device which can connect the basic principle of physics with what is observed in the real world. The harmonic oscillator is the bridge between pure and applied physics.

Han, D. (editor); Kim, Y. S. (editor); Zachary, W. W. (editor)

1993-01-01

86

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

E-print Network

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

So, Hing-Cheung

87

Physical Pendulum Experiments to Enhance the Understanding of Moments of Inertia and Simple Harmonic Motion  

ERIC Educational Resources Information Center

This paper describes a set of experiments aimed at overcoming some of the difficulties experienced by students learning about the topics of moments of inertia and simple harmonic motion, both of which are often perceived to be complex topics amongst students during their first-year university courses. By combining both subjects in a discussion…

Richardson, Tim H.; Brittle, Stuart A.

2012-01-01

88

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

89

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

90

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

SciTech Connect

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

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

2003-07-14

91

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

NASA Astrophysics Data System (ADS)

Third harmonic hydrogen cyclotron fast wave heating studies have begun on CDX-U to investigate the potential for bulk ion heating. In preparation for these studies, the available RF power in CDX-U has been increased to 0.5 MW. The operating frequency of the CDX-U RF transmitter was lowered to operate in the range of 8-10 MHz, providing access to the ion harmonic range 2? ˜4? in hydrogen. A similar regime is accessible for the 30 MHz RF system on NSTX, at 0.6 Tesla in hydrogen. Preliminary computational studies over the plasma regimes of interest for NSTX and CDX-U indicate the possibility of strong localized absorption on bulk ion species. Numerical simulation studies for relavent ST geometries will be presented, along with result for the CDX-U antenna experiments.

Spaleta, J.; Majeski, R.; Phillips, C. K.; Zakharov, L.; Kaita, R.

2004-11-01

92

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

93

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

94

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

95

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

96

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

97

Physics Teaching Technology Resource: Learning Cycles on Harmonic Motion and Waves  

NSDL National Science Digital Library

This learning cycle features nine videotaped experiments, organized sequentially for introducing fundamentals of harmonic motion and waves. Each video includes learning goal, prior knowledge required, and post-activity questions. Topics include period and amplitude, transverse and longitudinal wave motion, and motion of a pendulum. The instructional method is based on cognitive apprenticeship, in which students focus scientific process by observing, finding patterns, modeling, predicting, testing, and revising. The materials were designed to mirror the activities of scientists when they construct and apply knowledge. See Related Materials for links to the full collection by the same authors and for free access to an article explaining the theoretical basis for this instructional method.

Etkina, Eugenia

2011-11-18

98

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

99

Anomalies in high-order harmonic generation at relativistic intensities  

SciTech Connect

High-order harmonic generation from a solid target surface has been investigated using femtosecond laser pulses focused to intensities greater than 10{sup 18} W/cm{sup 2}. The experiments show that the harmonics are very intense, with a conversion efficiency that is one or two orders of magnitude larger than that of harmonics generated in gases. Beside the observation of presently the shortest wavelength harmonics from femtosecond-laser solid target interaction, i.e., down to 22 nm, an anomaly has been observed in the harmonic spectrum. In contrast to the expected well-known continuous 'roll off' of the high-harmonic orders, the harmonic intensity decreases with the increase of harmonic order, but in between shows minima which are significantly less intense than the neighboring harmonics. Furthermore, the order of the harmonic minima depend on target material. Additional calculations using numerical kinetic particle simulations and a simpler oscillating mirror model show that the physical origin of these modulations is an intricate interplay of resonance absorption and ponderomotive force which leads to a complex electron density profile evolution. Furthermore, this is emphasized by a spectral line analysis of the harmonics. In agreement with the theory, broad lines have been observed and, in particular for the harmonics in the minima, a complex interference structure is present.

Teubner, U.; Foerster, E. [Abteilung Roentgenoptik, Institut fuer Optik und Quantenelektronik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Pretzler, G.; Eidmann, K.; Witte, K. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching (Germany); Schlegel, Th. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

2003-01-01

100

Effective medium multipolar tensor analysis of second-harmonic generation from metal nanoparticles  

NASA Astrophysics Data System (ADS)

We present a detailed multipolar tensor analysis of second-harmonic (SH) generation from arrays of L-shaped gold nanoparticles. We define three effective nonlinear tensors, which include electric dipoles only (Aeee) and lowest-order magnetic (and quadrupole) effects at the fundamental (Aeem) and the SH (Amee) frequency. The components of the various tensors are distinguished through their different transformations as the experimental geometry is varied. The response is dominated by electric-dipole effects. However, the higher multipoles also play a significant role and are more important at the fundamental frequency than at the SH frequency. The results correlate well with the particles' plasmonic resonances and symmetry rules.

Zdanowicz, Mariusz; Kujala, Sami; Husu, Hannu; Kauranen, Martti

2011-02-01

101

3D shape analysis of heterochromatin foci based on a 3D spherical harmonics intensity model  

NASA Astrophysics Data System (ADS)

We propose a novel approach for 3D shape analysis of heterochromatin foci in 3D confocal light microscopy images of cell nuclei. The approach is based on a 3D parametric intensity model and uses a spherical harmonics (SH) expansion. The model parameters including the SH coefficients are automatically determined by least squares fitting of the model to the image intensities. Based on the obtained SH coefficients, a shape descriptor is determined, which enables distinguishing heterochromatin foci based on their 3D shape to characterize compaction states of heterochromatin. Our approach has been successfully applied to real static and dynamic 3D microscopy image data.

Eck, Simon; Wörz, Stefan; Müller-Ott, Katharina; Hahn, Matthias; Schotta, Gunnar; Rippe, Karsten; Rohr, Karl

2014-03-01

102

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

103

Use of harmonic inversion techniques in semiclassical quantization and analysis of quantum spectra  

NASA Astrophysics Data System (ADS)

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

Main, Jörg

1999-08-01

104

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

E-print Network

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

J. Main

1999-02-11

105

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

Microsoft Academic Search

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

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

2012-01-01

106

[Harmonic analysis fusion of hyperspectral image and its spectral information fidelity evaluation].  

PubMed

Combined with the Hyperion hyperspectral image and ALI high spatial resolution band of the EO-1 satellite, the paper puts forward the harmonic analysis fusion (HAF) algorithm of hyperspectral image and the derivative spectral d-value's information entropy (DSD-IE) model of the spectral-fused information fidelity evaluation. Through calculating and evaluating some parameters such as the DSD-IE values, average gradient and standard deviation of the sample spectra meanwhile compared with the fused hyperspectral images by the traditional methods like the principal component analysis (PCA), Gram-Schmidt and wavelet, the fused hyperspectral iamge by the HAF has proved to have the higher information degree of spatial integration and spectral fidelity, and the better superiorities in the reliability, accuracy and applicability. PMID:24369660

Yang, Keming; Zhang, Tao; Wang, Li-bo; Qian, Xiao-li; Wang, Lin-wei; Liu, Shi-wen

2013-09-01

107

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

108

PHYSICAL REVIEW E 89, 012902 (2014) First-harmonic approximation in nonlinear chirped-driven oscillators  

E-print Network

-driven oscillators Raam Uzdin, Lazar Friedland, and Omri Gat Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel (Received 22 May 2013; published 6 January 2014) Nonlinear classical oscillators can. This process is known as autoresonance (AR). We find that for a large class of oscillators, it is sufficient

Friedland, Lazar

109

Using a mobile phone acceleration sensor in physics experiments on free and damped harmonic oscillations  

NASA Astrophysics Data System (ADS)

We have used a mobile phone acceleration sensor, and the Accelerometer Monitor application for Android, to collect data in physics experiments on free and damped oscillations. Results for the period, frequency, spring constant, and damping constant agree very well with measurements obtained by other methods. These widely available sensors are likely to find increased use in instructional laboratories.

Carlos Castro-Palacio, Juan; Velázquez-Abad, Luisberis; Giménez, Marcos H.; Monsoriu, Juan A.

2013-06-01

110

Recent Developments in High-Harmonic Fast Wave Physics in NSTX  

SciTech Connect

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

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

2010-10-06

111

Simple Harmonic Motion  

NSDL National Science Digital Library

This site from HyperPhysics presents an introduction to simple harmonic motion. It is explained using a concept map that features equations and diagrams. Links to other concepts involved are also included.

Nave, C. R.; University, Department O.

112

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. © 2014 Wiley Periodicals, Inc. PMID:25327719

Berco, Dan; Hu, Chin-Kun

2014-11-15

113

Determination of hardness and hardness penetration depth of metal components by Non Linear Harmonics Analysis  

NASA Astrophysics Data System (ADS)

For the characterization of steel quality, hardness is a very important parameter. The magneto-inductive Non Linear Harmonics Analysis (NLHA) has been developed and used as a non destructive technique for measuring core hardness, surface hardness and hardness penetration depth of steel components. A description of the working principle of NLHA is given together with the setup of a typical hardness measuring system. Examples are given for the determination of carbon content in steel foils, measurement of core hardness in gear bolts where the hardness was controlled by tempering. Further results demonstrate measurements of core hardness, surface hardness and hardness penetration depth of nitration hardened steel samples. The final example shows a hardness profile of a case hardened shaft.

Stegemann, D.; Reimche, W.; Feiste, K. L.; Reichert, Ch.; Marques-Fetter, P.

1999-12-01

114

Work distribution in a time-dependent logarithmic-harmonic potential: exact results and asymptotic analysis  

NASA Astrophysics Data System (ADS)

We investigate the distribution of work performed on a Brownian particle in a time-dependent asymmetric potential well. The potential has a harmonic component with a time-dependent force constant and a time-independent logarithmic barrier at the origin. For an arbitrary driving protocol, the problem of solving the Fokker-Planck equation for the joint probability density of work and particle position is reduced to the solution of the Riccati differential equation. For a particular choice of the driving protocol, an exact solution of the Riccati equation is presented. An asymptotic analysis of the resulting expression yields the tail behavior of the work distribution for small and large work values. In the limit of a vanishing logarithmic barrier, the work distribution for the breathing parabola model is obtained.

Ryabov, Artem; Dierl, Marcel; Chvosta, Petr; Einax, Mario; Maass, Philipp

2013-02-01

115

Physics: A New Reactor Physics Analysis Toolkit  

Microsoft Academic Search

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

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

2011-01-01

116

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

117

Nonlinear time-harmonic finite-element analysis of coupled circuits and fields in low frequency electromagnetic devices  

Microsoft Academic Search

Many electromagnetic devices operate under sinusoidal excitation, in which case a time-harmonic (TH) analysis may be applied; in particular, a TH field solution is much more economic than a time-transient field solution. Although the material nonlinearity cannot be strictly taken into account in the TH case, it determines the true operating condition of the device, together with the external circuit

Rafael Escarela-Perez; E. Melgoza; Jose Alvarez-Ramirez; Ana Lilia Laureano-Cruces

2010-01-01

118

ACCURATE SHORT-TERM ANALYSIS OF THE FUNDAMENTAL FREQUENCY AND THE HARMONICS-TO-NOISE RATIO OF A SAMPLED SOUND  

Microsoft Academic Search

We present a straightforward and robust algorithm for periodicity detection, working in the lag (autocorrelation) domain. When it is tested for periodic signals and for signals with additive noise or jitter, it proves to be several orders of magnitude more accurate than the methods commonly used for speech analysis. This makes our method capable of measuring harmonics-to-noise ratios in the

Paul Boersma

1993-01-01

119

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

E-print Network

1 POWER ELECTRONICS HARMONIC ANALYSIS BASED ON THE LINEAR TIME PERIODIC MODELING. APPLICATIONS FOR AC/DC/AC POWER ELECTRONIC INTERFACE. Vanya Ignatova*, Pierre Granjon**, Seddik Bacha* *LEG in power electronic systems. The considered system is described by a set of differential equations, which

Paris-Sud XI, Université de

120

Spherical Harmonic Analysis. 2. A New Model Derived from Magnetic Observatory Data for Epoch 1960.0.  

National Technical Information Service (NTIS)

A new method of spherical harmonic analysis was applied to the annual mean of vector magnetic data from 82 observatories for epoch 1960.0. The resulting model of the geomagnetic field, containing 77 Gaussian coefficients, fits the observatory data with an...

P. F. Fougere

1964-01-01

121

Finite element 2D steady-state time harmonic field analysis of induction motor  

Microsoft Academic Search

This work describes a method of calculating the steady state harmonic field distribution of an induction motor. A finite element based model, which predicts the magnetic field throughout in induction motor during steady state conditions, is established. The harmonic components of magnetic field and the spatial distribution corresponding to each of the frequency components are calculated for an induction motor

Ajay Kumar; Sanjay Marwaha; Anupama Marwaha

2004-01-01

122

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

123

The life expectancy analysis for an electric motor due to harmonics  

Microsoft Academic Search

One of the effects of voltage and current harmonics within the power systems is ageing of the insulation of electrical equipment and components and thus shortening of their useful life. In the rotating machines harmonics cause additional stator and rotor losses and reduce the output torque. In this sense, the purpose of this paper is to determine an electric motor

Aslan Inan; Ferit Attar

1998-01-01

124

Analysis of distribution transformer losses and life expectancy using measured harmonic data  

Microsoft Academic Search

Three-phase distribution transformer in electrical power systems are usually designed for utilizing at the rated frequency and linear load. A different performance compared with that of the designed transformer occur when non-linear loads introduce harmonics to the supply. With the increasing use of nonlinear load the harmonic ay overheat the transformer leading to a poor power quality. The increased losses

D. M. Said; K. M. Nor; M. S. Majid

2010-01-01

125

Analysis of human knee osteoarthritic cartilage using polarization sensitive second harmonic generation microscopy  

NASA Astrophysics Data System (ADS)

Osteoarthritis is one of the most prevalent joint diseases in the world. Although the cause of osteoarthritis is not exactly clear, the disease results in a degradation of the quality of the articular cartilage including collagen and other extracellular matrix components. We have investigated alterations in the structure of collagen fibers in the cartilage tissue of the human knee using mulitphoton microscopy. Due to inherent high nonlinear susceptibility, ordered collagen fibers present in the cartilage tissue matrix produces strong second harmonic generation (SHG) signals. Significant morphological differences are found in different Osteoarthritic grades of cartilage by SHG microscopy. Based on the polarization analysis of the SHG signal, we find that a few locations of hyaline cartilage (mainly type II collagen) is being replaced by fibrocartilage (mainly type I cartilage), in agreement with earlier literature. To locate the different types and quantify the alteration in the structure of collagen fiber, we employ polarization-SHG microscopic analysis, also referred to as _-tensor imaging. The image analysis of p-SHG image obtained by excitation polarization measurements would represent different tissue constituents with different numerical values at pixel level resolution.

Kumar, Rajesh; Grønhaug, Kirsten M.; Romijn, Elisabeth I.; Drogset, Jon O.; Lilledahl, Magnus B.

2014-05-01

126

Scheduling Data Intensive Particle Physics Analysis Jobs  

E-print Network

Scheduling Data Intensive Particle Physics Analysis Jobs on Clusters of PCs S. Ponce European Laboratory for Particle Physics (CERN) Information Technology Department CH-1211 Geneva 23, Switzerland are proposed for parallelizing data intensive particle physics analysis ap- plications on computer clusters

Hersch, Roger D.

127

Second harmonic generation microscopy analysis of extracellular matrix changes in human idiopathic pulmonary fibrosis.  

PubMed

Patients with idiopathic fibrosis (IPF) have poor long-term survival as there are limited diagnostic/prognostic tools or successful therapies. Remodeling of the extracellular matrix (ECM) has been implicated in IPF progression; however, the structural consequences on the collagen architecture have not received considerable attention. Here, we demonstrate that second harmonic generation (SHG) and multiphoton fluorescence microscopy can quantitatively differentiate normal and IPF human tissues. For SHG analysis, we developed a classifier based on wavelet transforms, principle component analysis, and a K-nearest-neighbor algorithm to classify the specific alterations of the collagen structure observed in IPF tissues. The resulting ROC curves obtained by varying the numbers of principal components and nearest neighbors yielded accuracies of >95%. In contrast, simpler metrics based on SHG intensity and collagen coverage in the image provided little or no discrimination. We also characterized the change in the elastin/collagen balance by simultaneously measuring the elastin autofluorescence and SHG intensities and found that the IPF tissues were less elastic relative to collagen. This is consistent with known mechanical consequences of the disease. Understanding ECM remodeling in IPF via nonlinear optical microscopy may enhance our ability to differentiate patients with rapid and slow progression and, thus, provide better prognostic information. PMID:25134793

Tilbury, Karissa; Hocker, James; Wen, Bruce L; Sandbo, Nathan; Singh, Vikas; Campagnola, Paul J

2014-08-01

128

A back-to-front derivation: the equal spacing of quantum levels is a proof of simple harmonic oscillator physics  

Microsoft Academic Search

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 mapping between the provision of equally spaced

David L. Andrews; Luciana C. Dávila Romero

2009-01-01

129

Analysis of Astrophysics and Particle Physics Data  

E-print Network

Analysis of Astrophysics and Particle Physics Data using Optimal Segmentation Jeffrey.D.Scargle@nasa.gov Space Science Division NASA Ames Research Center Santa Cruz Institute for Particle Physics May 17, 2005

California at Santa Cruz, University of

130

[Multi-harmonic analysis of quasi-continuous-wave laser modulation absorption spectroscopy].  

PubMed

Numerous harmonic components such as multiple frequency, sum frequency and difference frequency of multiple modulation signals were found in quasi-continuous-wave (QCW) diode laser modulation absorption spectroscopy. Then, the authors analyzed these harmonic components' existence in terms of non-linear interactions of laser and gas absorption line. And the signals' characteristics were studied experimentally. The results shows that there are some sum frequency and difference frequency components that have larger amplitudes compared to the second harmonic wavelength modulation spectroscopy signal (2f-WMS) commonly used in tunable diode laser spectroscopy (TDLAS), and it may improve the detection sensitivity of QCW modulation spectroscopy. PMID:22582610

Qi, Ru-bin; Du, Zhen-hui; Meng, Fan-li; Li, Jin-yi; Gao, Dong-yu; Xu, Xiao-bin; Chen, Wen-liang; Xu, Ke-xin

2012-03-01

131

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

132

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

Microsoft Academic Search

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

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

133

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

134

Flux Dynamic Changes by Neutron Irradiation in BISCCO: High Harmonics AC Susceptibility Analysis  

Microsoft Academic Search

High harmonics ac susceptibility measurements joint with neutron irradiations on quasi-bi-dimensional high temperature superconductor (quasi-2D-HTSC) are good tools to study the flux dynamics and its interaction with pinning processes in these superconductors. Flux neutron intensity of shows a deep change in the flux pinning dynamics in Bi-Sr-Ca-Cu-O (BSCCO) system. Third harmonic susceptibility signal increases in amplitude after the neutron irradiation,

Daniele Di Gioacchino; Paolo Tripodi; Jenny Darja Vinko; Valentina Mihalache; Stelian Popa

2007-01-01

135

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

PubMed Central

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

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

2014-01-01

136

Measurement uncertainty analysis in medical physics.  

E-print Network

??This research demonstrates that an internationally recognised measurement uncertainty analysis process, the GUM, can be successfully applied within the field of Medical Physics. The research… (more)

Gregory, Kent

2011-01-01

137

Physics analysis tools for beauty physics in ATLAS  

NASA Astrophysics Data System (ADS)

The Large Hadron Collider experiments will search for physics phenomena beyond the Standard Model. Highly sensitive tests of beauty hadrons will represent an alternative approach to this research. The analysis of complex decay chains of the beauty hadrons have to efficiently extract the detector tracks made by these reactions and reject other events in order to make sufficiently precise measurement. This places severe demands on the software used to analyze the B-physics data. The ATLAS B-physics group has written a series of tools and algorithms for performing these tasks, to be run within the ATLAS offline software framework Athena. This paper describes this analysis suite, paying particular attention to mechanisms for handling combinatorics, interfaces to secondary vertex fitting packages, B-flavor tagging tools and finally Monte Carlo true information association to pursue simulation data in process of the software validations which is an important part of the development of the physics analysis tools.

Anastopoulos, C.; B-Thacker, E.; Catmore, J.; Dallison, S.; Derue, F.; Epp, B.; Jussel, P.; Kaczmarska, A.; Mora, L. d.; Radziewski, H. v.; ?ezní?ek, P.; Stahl, T.

2008-07-01

138

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

NASA Technical Reports Server (NTRS)

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

Jin, R. S.

1975-01-01

139

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

140

The Analysis and Measurement of Harmonics in the Vicinity of an HVDC Inverter  

Microsoft Academic Search

High voltage DC (HVDC) transmission systems are designed to interface with the AC network in such a way as to have considerable operating flexibility and minimal harmonic impact. Filter design as well as gating controls are designed at the inverter with the stated objective in view. Sometimes designs and operating regimes are an engineering compromise relating to the amplitude of

D. Carlson; L. Crane; C. Fedora; A. Lucero; R. Parenteau; J. Peterson; A. Tredeau; G. Heydt; M. Marz; B. McEnany

1986-01-01

141

Analysis of harmonic transfer in an AC excited generator including speed ripple  

Microsoft Academic Search

AC excited generators are favoured in some applications due to their features including generation at a constant frequency but a variable speed. With the rotor windings supplied from a static power electronic converter, harmonics are one of the major concerns in such systems. Based on a mathematical model of the AC excited machine, a method is developed to analyze the

Y. Liao; D. Xiang; L. Ran; G. A. Putrus

2002-01-01

142

Critical Analysis of the Current and Voltage Superposition Approaches at Sharing Harmonic Distortion Responsibility  

Microsoft Academic Search

Faced with the guidelines contained in documents approved by the National Electric Power Agency PRODIST - Module 8, amongst other indicators of electric power supply quality, the harmonic distortions appear as an important issue. The mentioned regulation takes into account specific matters such as definitions, measurement procedures, benchmarks, etc. Focusing the subject of voltage distortions and the establishment of approaches

Ivan Nunes Santos; Jose Carlos de Oliveira

2011-01-01

143

Modeling the lithospheric magnetic field over France by means of revised spherical cap harmonic analysis  

E-print Network

Modeling the lithospheric magnetic field over France by means of revised spherical cap harmonic first vector lithospheric field model over France, which extends from surface to 500 km of altitude radius. The magnetic lithospheric map consistency is confirmed with a comparison to known geological

Thébault, Erwan

144

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

145

Harmonic Convergence  

NSDL National Science Digital Library

Harmonic convergence refers to a day back in 1987 where there was a particular planetary alignment. New Agers went crazy over the event, and if you want to get a taste of what it was like, enter harmonic convergence into your favorite Internet search engine and sit back and enjoy. This chapter adds to the previous discussion of resonance by expanding the list of vibrating things to metal rods and columns of air.

Robertson, William C.

2003-01-01

146

Dealing with periodical loads and harmonics in operational modal analysis using time-varying transmissibility functions  

NASA Astrophysics Data System (ADS)

Periodical loads, such as waves and rotating machinery, form a problem for operational modal analysis (OMA). In OMA only the vibrations of a structure of interest are measured and little to nothing is known about the loads causing these vibrations. Therefore, it is often assumed that all dynamics in the measured data are linked to the system of interest. Periodical loads defy this assumption as their periodical behavior is often visible within the measured vibrations. As a consequence most OMA techniques falsely associate the dynamics of the periodical load with the system of interest. Without additional information about the load, one is not able to correctly differentiate between structural dynamics and the dynamics of the load. In several applications, e.g. turbines and helicopters, it was observed that because of periodical loads one was unable to correctly identify one or multiple modes. Transmissibility based OMA (TOMA) is a completely different approach to OMA. By using transmissibility functions to estimate the structural dynamics of the system of interest, all influence of the load-spectrum can be eliminated. TOMA therefore allows to identify the modal parameters without being influenced by the presence of periodical loads, such as harmonics. One of the difficulties of TOMA is that the analyst is required to find two independent datasets, each associated with a different loading condition of the system of interest. This poses a dilemma for TOMA; how can an analyst identify two different loading conditions when little is known about the loads on the system? This paper tackles that problem by assuming that the loading conditions vary continuously over time, e.g. the changing wind directions. From this assumption TOMA is developed into a time-varying framework. This development allows TOMA to not only cope with the continuously changing loading conditions. The time-varying framework also enables the identification of the modal parameters from a single dataset. Moreover, the time-varying TOMA approach can be implemented in such a way that the analyst no longer has to identify different loading conditions. For these combined reasons the time-varying TOMA is less dependent on the user and requires less testing time than the earlier TOMA-technique.

Weijtjens, Wout; Lataire, John; Devriendt, Christof; Guillaume, Patrick

2014-12-01

147

Passive harmonic filtering systems for low power PWM ASDs: A comparative analysis and perspectives  

Microsoft Academic Search

The main goal of the paper is to discuss about usefulness, drawbacks and perspectives of single-phase PWM adjustable speed drives (ASDs) for low-power three-phase induction motors. Their positive impact on energy saving in large-scale residential house appliances is underlined. A great attention is devoted to the problem of generation of current harmonic components, both on the motor-side and on the

R. Carbone; A. Tomaselli

2010-01-01

148

High-dimensional Harmonic Balance Analysis for Second-order Delay-differential Equations  

Microsoft Academic Search

This paper demonstrates the utility of the High Dimensional Harmonic Balance (HDHB) method for locating limit cycles of second-order delay-difierential equations. A matrix version of the HDHB method for systems of delay-difierential equations is described in detail. The method has been successfully applied to capture the stable and\\/or unstable limit cycles in three difierent models: a machine tool vibration model,

Liping Liu; T. Kalmar-Nagy

2010-01-01

149

Isoparametric finite element analysis of time-harmonic electromagnetic fields in three dimensions  

Microsoft Academic Search

A three-dimensional finite element vector formulation is described for finding the time-harmonic electromagnetic fields in some volume of space containing arbitrary shaped, lossless, inhomogeneous dielectric materials. For flexibility of the curved boundaries description, an isoparametric representation is used by means of quadratic polynomial-based shape functions. The method allows the evaluation of resonance as well as excited fields. A three-dimensional calculation

S. Silaev

1993-01-01

150

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

151

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

152

Symbolic Vector Analysis in Plasma Physics  

Microsoft Academic Search

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,

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

1997-01-01

153

Digital Movement Analysis in Physical Education  

ERIC Educational Resources Information Center

Mobile devices such as smartphones and tablets offer applications (apps) that make digital movement analysis simple and efficient in physical education. Highly sophisticated movement analysis software has been available for many years but has mainly appealed to coaches of elite athletes and biomechanists. Apps on mobile devices are less expensive…

Trout, Josh

2013-01-01

154

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

155

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

156

Present status of JADE's ??-physics analysis  

Microsoft Academic Search

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

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

157

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

158

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

159

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

160

In pixel analysis of molecular structure with Stokes vector resolved second harmonic generation microscopy  

NASA Astrophysics Data System (ADS)

We report on measurements and characterization of polarization properties of Second Harmonic (SH) signals using a four-channel photon counting based Stokes polarimeter from type I collagen and starch granules. In this way, the critical polarization parameters including the degree of polarization (DOP), the degree of linear polarization (DOLP), and the degree of circular polarization (DOCP), are extracted from the reconstructed Stokes vector based SH images in a pixel-by-pixel manner. The measurements are further extended to determine the molecular structure and orientation of the samples by varying the polarization states of the incident light and recording the resulting Stokes parameters of the SH signal. The combination of SHG microscopy and Stokes polarimeter hence makes a powerful tool to investigate the structural order of starch granules under water and heating environment.

Mazumder, Nirmal; Xiang, Lu Yun; Qiu, Jianjun; Kao, Fu-Jen

2014-02-01

161

Earth zonal harmonics from rapid numerical analysis of long satellite arcs  

NASA Technical Reports Server (NTRS)

A zonal geopotential is presented to degree 21 from evaluation of mean elements for 21 satellites including 2 of low inclination. Each satellite is represented by an arc of at least one apsidal rotation. The lengths range from 200 to 800 days. Differential correction of the initial elements in all of the arcs, together with radiation pressure and atmospheric drag coefficients, was accomplished simultaneously with the correction for the zonal harmonics. The satellite orbits and their variations are generated by numerical integration of the Lagrange equations for mean elements. Disturbances due to precession and nutation of the earth's pole, atmospheric drag, radiation pressure and luni-solar gravity are added at from 1- to 8-day intervals in the integrated orbits. The results agree well with recent solutions from other authors using different methods and different satellite sets.

Wagner, C. A.

1972-01-01

162

Quantitative analysis of thermally-induced alterations of corneal stroma by second-harmonic generation imaging  

NASA Astrophysics Data System (ADS)

Thermal modifications induced in the corneal stroma were investigated by means of second harmonic generation (SHG) imaging. Whole fresh cornea samples were heated in a water bath at temperatures in the 35-80 °C range for a 4-min time. SHG images of the structural modifications induced at each temperature were acquired from different areas of cross-sectioned corneal stroma by using an 880 nm linearly- and circularly-polarized excitation light emitted by a mode-locked Ti:Sapphire laser. The SHG images were then analyzed by means of both an empirical approach and a 2D-theoretical model. The proposed analyses provide a detailed description of the changes occurring in the structural architecture of the cornea during the thermal treatment. Our results allow us to depict a temperature-dependent biochemical model for the progressive destructuration occurring to collagen fibrils and nonfibrillar components of the stroma.

Matteini, P.; Rossi, F.; Ratto, F.; Cicchi, R.; Kapsokalyvas, D.; Pavone, F. S.; Pini, R.

2010-02-01

163

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

164

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

165

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, GeneralVectorAnalysis (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.; Rewoldt, G.; Tang, W.M.

1997-10-01

166

Symbolic Vector Analysis in Plasma Physics  

Microsoft Academic Search

Many problems in plasma physics involve substantial amounts of analytical vector calculation. The complexity usually originates from both the vector operations;\\u000athemselves and the choice of underlying coordinate system. A computer algebra package for symbolic vector analysis in general coordinate systems,;\\u000aGeneralVectorAnalysis (GVA), is developed using Mathematica. The modern viewpoint for 3D vector calculus, differential forms on 3-manifolds, is adopted

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

1997-01-01

167

Symbolic vector analysis in plasma physics  

Microsoft Academic Search

Many problems in plasma physics involve substantial amounts of analytical vector calculation. The complexity usually originates from both the vector operations themselves and the underlying coordinate systems. A computer algebra package for symbolic vector analysis in general coordinate systems, GeneralVectorAnalysis (GVA), is developed using Mathematica. The modern viewpoint for 3D vector calculus, differential forms on 3-manifolds, is adopted to unify

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

1999-01-01

168

Virtual MIMO Network A Physical Wireless Analysis  

E-print Network

Virtual MIMO Network A Physical Wireless Analysis Jean-Marc Kelif Orange Labs Issy location. As an application of this model, we propose an analytical study of a virtual MIMO network. Indeed, in a simple way, the impact of virtual MIMO on the instantaneous throughput. We moreover show that the outage

Paris-Sud XI, Université de

169

Harmonic engine  

SciTech Connect

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

170

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

E-print Network

Cylindrical implosions driven by intense heavy ions beams should be instrumental in a near future to study High Energy Density Matter. By rotating the beam by means of a high frequency wobbler, it should be possible to deposit energy in the outer layers of a cylinder, compressing the material deposited in its core. The beam temporal profile should however generate an inevitable irradiation asymmetry likely to feed the Rayleigh-Taylor instability (RTI) during the implosion phase. In this paper, we compute the Fourier components of the target irradiation in order to make the junction with previous works on RTI performed in this setting. Implementing a 1D and 2D beam models, we find these components can be expressed exactly in terms of the Fourier transform of the temporal beam profile. If $T$ is the beam duration and $\\Omega$ its rotation frequency, "magic products" $\\Omega T$ can be identified which cancel the first harmonic of the deposited density, resulting in an improved irradiation symmetry.

Bret, Antoine; Tahir, Naeem

2012-01-01

171

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

172

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

PubMed

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

2012-07-01

173

Face recognition in global harmonic subspace  

Microsoft Academic Search

In this paper, a novel pattern recognition scheme, global harmonic subspace analysis (GHSA), is developed for face recognition. In the proposed scheme, global harmonic features are extracted at the semantic scale to capture the 2-D semantic spatial structures of a face image. Laplacian Eigenmap is applied to discriminate faces in their global harmonic subspace. Experimental results on the Yale and

Richard M. Jiang; Danny Crookes; Nie Luo

2010-01-01

174

Global QCD Analysis and Hadron Collider Physics  

SciTech Connect

The role of global QCD analysis of parton distribution functions (PDFs) in collider physics at the Tevatron and LHC is surveyed. Current status of PDF analyses are reviewed, emphasizing the uncertainties and the open issues. The stability of NLO QCD global analysis and its prediction on 'standard candle' W/Z cross sections at hadron colliders are discussed. The importance of the precise measurement of various W/Z cross sections at the Tevatron in advancing our knowledge of PDFs, hence in enhancing the capabilities of making significant progress in W mass and top quark parameter measurements, as well as the discovery potentials of Higgs and New Physics at the Tevatron and LHC, is emphasized.

Tung, W.-K. [Michigan State University, E. Lansing, MI (United States)

2005-03-22

175

Visual physics analysis - from desktop to physics analysis at your fingertips  

NASA Astrophysics Data System (ADS)

Visual Physics Analysis (VISPA) is an analysis environment with applications in high energy and astroparticle physics. Based on a data-flow-driven paradigm, it allows users to combine graphical steering with self-written C++ and Python modules. This contribution presents new concepts integrated in VISPA: layers, convenient analysis execution, and web-based physics analysis. While the convenient execution offers full flexibility to vary settings for the execution phase of an analysis, layers allow to create different views of the analysis already during its design phase. Thus, one application of layers is to define different stages of an analysis (e.g. event selection and statistical analysis). However, there are other use cases such as to independently optimize settings for different types of input data in order to guide all data through the same analysis flow. The new execution feature makes job submission to local clusters as well as the LHC Computing Grid possible directly from VISPA. Web-based physics analysis is realized in the VISPA@Web project, which represents a whole new way to design and execute analyses via a standard web browser.

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

2012-06-01

176

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

177

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

E-print Network

by the low-altitude satellite DEMETER Michel Parrot1 , Frantisek Nmec2 , and Ondej Santol�k2,3 1 LPC2E Republic, 3 Institute of Atmospheric Physics AS CR, Prague, Czech Republic Abstract DEMETER was a low in the magnetosphere was first obtained from the ground-based observations [Helliwell et al., 1975]. Before the DEMETER

Santolik, Ondrej

178

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

179

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

PubMed

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

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

2013-01-01

180

Lunar physical librations and laser ranging  

Microsoft Academic Search

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

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

1973-01-01

181

Almansi Theorems in Umbral Clifford Analysis and the Quantum Harmonic Oscillator  

Microsoft Academic Search

We introduce the Umbral calculus into Clifford analysis starting from the abstract of the Heisenberg commutation relation $[\\\\frac{d}{dx}, x] = {\\\\bf id}$. The Umbral Clifford analysis provides an effective framework in continuity and discreteness. In this paper we consider functions defined in a star-like domain $\\\\Omega \\\\subset \\\\BR^n$ with values in the Umbral Clifford algebra $C\\\\ell_{0,n}'$ which are Umbral polymonogenic

Guangbin Ren; Nelson Faustino

2009-01-01

182

Physical optics analysis of HARP-B  

NASA Astrophysics Data System (ADS)

We present a physical optics analysis of the Heterodyne Array Receiver Program B-band (HARP-B) receiver for the James Clerk Maxwell Telescope (JCMT). Three sets of calculations are performed: 1. A Gaussian beam analysis to determine grid sizes for the Mach-Zehnder polarising interferometer. It is shown that an optimum grid size of 150mm clear diameter has little effect on the beam pattern and transmission of power through the system. 2. A Model of the HARP-B Imaging array is created using an ideal beam pattern for the corrugated feed. This produces an accurate beam pattern of minimal distortion. 3. The throughput and beam patterns for the whole HARP-B system are calculated. This produced beam patterns showing a high degree of symmetry with acceptable power coupling to the reflectors.

Williamson, Ross; Hills, Richard E.; Smith, Harry

2003-02-01

183

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

E-print Network

of a musical signal by means of some notation system. In many music genres, including western music, a big deal 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

Richard, Gaël

184

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

E-print Network

. Karpovsky2 Dept. of Computer Science, Faculty of Electronics, 18 000 Nis, Serbia 1 Tampere International, Euler applied the method he disclosed to a function derived from analysis of movement of planets [11]. This article actually contains what is now called the Fourier series, and Euler provided also

Karpovsky, Mark

185

The designated harmonic suppression for SPWM  

NASA Astrophysics Data System (ADS)

SPWM is a critical method used in asynchronous motor-driven area. But harmonic components of inverter output wave impair its application in motor speed control. A new mixed algorithm was proposed for SPWM, which was a designated harmonic suppression technology by way of improved regular sampling in low voltage and low frequency and harmonic elimination in high voltage and high frequency. This algorithm was based on both analysis of sampled SPWM and Fourier series transform method and aimed at eliminating some odd harmonic components to obtain an identical sine wave. After explication of the harmonic elimination procedure and real time calculation process, an effective control mode and its control circuit were put forward so that the designated harmonic suppression made a reality. Applied it in whole speed adjusting range, the voltage can be conveniently controlled and high frequency harmonic components of SPWM are also improved.

Ping, Yang; Yang, Shi-ping

2005-12-01

186

Parallel-Connected Photovoltaic Inverters: Zero Frequency Sequence Harmonic Analysis and Solution  

NASA Astrophysics Data System (ADS)

High-power photovoltaic (PV) plants are usually constituted of the connection of different PV subfields, each of them with its interface transformer. Different solutions have been studied to improve the efficiency of the whole generation system. In particular, transformerless configurations are the more attractive one from efficiency and costs point of view. This paper focuses on transformerless PV configurations characterised by the parallel connection of interface inverters. The problem of zero sequence current due to both the parallel connection and the presence of undesirable parasitic earth capacitances is considered and a solution, which consists of the synchronisation of pulse-width modulation triangular carrier, is proposed and theoretically analysed. The theoretical analysis has been validated through simulation and experimental results.

Carmeli, Maria Stefania; Mauri, Marco; Frosio, Luisa; Bezzolato, Alberto; Marchegiani, Gabriele

2013-05-01

187

Analysis of physical activities in Taekwondo Pumsae.  

PubMed

Exercise is very important element for successful aging. Among many sports events, Korea is the suzerain of Taekwondo. When competing (Taekwondo Free Fighting) after learning Poomse as basic movements and inuring them, people compete with movements depending on situation. Among Poomses of Taekwondo, Taegeuk Poomse consists of very basic movements from 1 Jang to 8 Jang and they are for inuring to body. In order to prescribe Taegeuk Jang, which is the basic movement of Taekwondo that Korea is the suzerain, as an exercise for successful aging, it is necessary to analyze physical activity level of each Taegeuk Jang (From 1 Jang through 8 Jang) and suggest the same. Therefore, in this study, I analyzed physical activity level of each Jang of Taegeuk Poomse by attaching Armband made by Body Media Company on brachia and legs below knee of Taekwondo trainees. The result of the analysis of the whole momentum from Taegeuk 1 Jang to 8 Jang is as follows: First, the average absolute value of acceleration variation of vertical direction signal (L-MAD): 5.15. Second, the average absolute value of acceleration variation of horizontal direction signal (T-MAD): 3.44. Finally, the average of calorie consumption per minute (AEE/Min): 5.06 Cal. The obtained result corresponds to proper exercise condition for successful aging and it can be utilized as data for exercise prescription for the young and the old. PMID:19163880

Lee, Sang-Bock; Cha, Eun-Jong; Lee, Tae-Soo

2008-01-01

188

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

189

Standing Waves: Harmonics and Patterns  

NSDL National Science Digital Library

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

Henderson, Tom

2010-08-27

190

Simple Harmonic Oscillator Model  

NSDL National Science Digital Library

The Ejs Simple Harmonic Oscillator model displays the dynamics of a ball attached to an ideal spring. The spring is initially stretched and the ball has zero initial velocity. The initial position of the ball can be changed by click-dragging the ball when the simulation is paused. 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 Simple Harmonic Oscillator 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_osc_SHO.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 Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-05

191

Strange Harmonic Oscillator Model  

NSDL National Science Digital Library

The Ejs Strange Harmonic Oscillator model displays the motion of two masses connected by a massless rigid rod and the masses may move without friction along two perpendicular rails in a horizontal table. The energy of the oscillator system can be changed via a slider. 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 Strange Harmonic Oscillator 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_strange.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

192

The Analysis of Student Attainment of Course Objectives in Physics  

ERIC Educational Resources Information Center

Analyzes using path analysis models, student attainment of the objectives of a first year university physics course. Four aspects of physics attainment are identified: (1) theoretical; (2) applied; (3) experimental; and (4) attitudinal objectives. (HM)

Osborne, Roger

1978-01-01

193

Harmonic Oscillators as Bridges between Theories  

SciTech Connect

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

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

2005-03-31

194

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

195

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

196

Analysis of fragmentation in shock physics simulation  

Microsoft Academic Search

Analyzing shock physics, which can involve high energies, high velocity materials, and highly variable results, is challenging. Very little can be measured during a shock physics experiment. Most experimental data is collected in the aftermath. High-fidelity simulations using codes like CTH are possible, but require a significant amount of post processing to properly understand the results. Physical structures and their

Kenneth Moreland; C. Charles Law; L. Ice; D. Karelitz

2008-01-01

197

Spherical cap harmonic analysis  

Microsoft Academic Search

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

G. V. Haines

1985-01-01

198

Morphology of the Iceland Basin Excursion from a spherical harmonics analysis and an iterative Bayesian inversion procedure of sedimentary records  

NASA Astrophysics Data System (ADS)

Based on 5 published marine high-resolution sedimentary records of the Iceland Basin Excursion [IBE; Channell, J.E.T., Hodell, D.A., Lehman, B., 1997. Relative geomagnetic paleointensity and ? 18O at ODP Site 983/Gardar Drift, North Atlantic since 350 ka. Earth Planet. Sci. Lett. 153, 103-118; Laj, C., Kissel, C., Roberts, A., 2006. Geomagnetic field behavior during the Iceland Basin and Laschamp geomagnetic excursions: a simple transitional field geometry? Geochem. Geophys. Geosystems. 7, Q03004, doi:10.1029/2005GC001122] dated around 186-190 kyr, we present models of the excursional geomagnetic field at the Earth's surface using two different approaches. First a spherical harmonics analysis is performed after synchronization of the records using their paleointensity profiles. Second, we have used an iterative Bayesian inversion procedure, calibrated using the single volcanic data available so far. Both modeling approaches suffer from imperfections of the paleomagnetic signals and mostly from the still poor geographical distribution of detailed records, presently available only from the North Atlantic and the West Pacific. For these reasons, our modeling results should only be regarded as preliminary models of the geomagnetic field during the IBE, susceptible to improvements when including results from future paleomagnetic studies. Nevertheless, both approaches show distinct similarities and are stable against moderate variations of modeling parameters. The general picture is that of a dipole field undergoing a strong reduction, but remaining higher than the non-dipole field all through the excursional process, except for a very short interval of time corresponding to the dipole minimum at the center of the excursion. On the other hand, some differences exist between the results of the two models with each other and with the real data when the virtual geomagnetic pole (VGP) paths are considered. The non-dipole field does not appear to undergo very significant changes during the excursion except for a slight increase just at the dipole minimum. The width of mid-height of the dipole minimum, which can be considered as an approximate measure of the duration of the IBE is of the order of 3 kyr according to the SPECMAP age model, consistent with a suggestion by Gubbins [Gubbins, D., 1999. The distinction between geomagnetic excursions and reversals. Geophys. J. Int. 137, F1-F3]. These results are compared to those obtained for the Matuyama-Brunhes geomagnetic reversal [Leonhardt, R., Fabian, K., 2007. Paleomagnetic reconstruction of the global geomagnetic field evolution during the Matuyama/Brunhes transition: iterative Bayesian inversion and independent verification. Earth Planet. Sci. Lett. 253, 172-195].

Lanci, Luca; Kissel, Catherine; Leonhardt, Roman; Laj, Carlo

2008-08-01

199

Global analysis of crisis in twin-well Duffing system under harmonic excitation in presence of noise  

Microsoft Academic Search

Evolution of a crisis in a twin-well Duffing system under a harmonic excitation in presence of noise is explored in detail by the generalized cell mapping with digraph (GCMD in short) method. System parameters are chosen in the range that there co-exist chaotic attractors and\\/or chaotic saddles, together with their evolution. Due to noise effects, chaotic attractors and chaotic saddles

Wei Xu; Qun He; Tong Fang; Haiwu Rong

2005-01-01

200

Fundamental and Harmonic-Frequency Circuit-Model Analysis of Lnterdigital Transducers with Arbitralry Metallization Ratios and Polarity Sequences  

Microsoft Academic Search

A three-port circuit model is developed that describes the operation of interdigital transducers with arbitrary metallization ratios and electrode-polarity sequences at fundamental and higher harmonic frequencies. The electric fields that excite surface acoustic waves are found on an electrode-by-electrode basis using the approximation that the local electric fields are not influenced by electrodes more distant than the next-nearest neighbors. The

W. RICHARD SMITH; WILLIAM F. PEDLER

1975-01-01

201

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 in depth · Overlaying in different ways · Browsing Fast Camera data ·EFITmovies and EFITviewer

Princeton Plasma Physics Laboratory

202

Symbolic Vector Analysis in Plasma Physics.  

National Technical Information Service (NTIS)

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 symbo...

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

1997-01-01

203

Artificial Cobweb: Chemical and Physical Analysis.  

National Technical Information Service (NTIS)

Here we list only the most important chemical and physical properties of the foreign matter that was 'delivered' in the Croatian atmosphere in respectable amounts: - man-made product, organic fibrous matter - composite structure of at least two materials ...

K. Furic, Z. Orehovec

2001-01-01

204

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

205

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

206

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

207

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

208

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

209

Measuring noninertial physics of turbulence: Quasiscaling analysis  

NASA Astrophysics Data System (ADS)

Quasiscaling exponent ?nM;D is introduced by the ratio of turbulence velocity structure functions Sn(rD)/Sn(rM)=(rD/rM)?nM;D at scales rM and rD to measure the viscous and large-scale effects. Two inertial phenomenologies, respectively, that by She and Leveque [Phys. Rev. Lett. 72, 336 (1994)] and that by Meneveau and Sreenivason [Phys. Rev. Lett. 59, 1424 (1987)], are extended for quasiscaling as case studies. Both extended models fit well to the measurements and quantify the noninertial behaviors from different physical aspects, i.e., logarithmic-nonhomogeneous Poissonian and nonconservative binomial cascade, through the scale-dependent behaviors of the model parameters extracted from experimental data; and the physical meanings of the extended self-similarity properties for them are exposed.

Zhu, Jian-Zhou

2005-08-01

210

Atmospheric cloud physics thermal systems analysis  

NASA Technical Reports Server (NTRS)

Engineering analyses performed on the Atmospheric Cloud Physics (ACPL) Science Simulator expansion chamber and associated thermal control/conditioning system are reported. Analyses were made to develop a verified thermal model and to perform parametric thermal investigations to evaluate systems performance characteristics. Thermal network representations of solid components and the complete fluid conditioning system were solved simultaneously using the Systems Improved Numerical Differencing Analyzer (SINDA) computer program.

1977-01-01

211

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

212

NASA Space Plasma Physics Research and Analysis Program  

Microsoft Academic Search

The Research and Analysis (R&A) program of the National Aeronautics and Space Administration (NASA) Space Plasma Physics Branch of the Office of Space Science and Applications supports more than 150 grants and contracts for research. This research program is the primary means by which NASA maintains and advances the broad-based infrastructure for research in space plasma physics in a way

Timothy E. Eastman

1987-01-01

213

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.

214

Benchmarking patient improvement in physical therapy with data envelopment analysis  

Microsoft Academic Search

Purpose – The purpose of this article is to present a case study that documents how management science techniques (in particular data envelopment analysis) can be applied to performance improvement initiatives in an inpatient physical therapy setting. Design\\/methodology\\/approach – The data used in this study consist of patients referred for inpatient physical therapy following total knee replacement surgery (at a

Daniel Friesner; Donna Neufelder; Janet Raisor; Mohammed Khayum

2005-01-01

215

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

216

Single Phase Harmonic Limits  

Microsoft Academic Search

The International Electrotechnical Commission (IEC) sets limits for harmonics in the current of small single-phase or three-phase loads, less than 16 A per phase, in Electromagnetic compatibility (EMC) - Part 3-2: Limits - Limits for harmonic current emissions (IEC 61000-3-2). The IEEE Single Phase Harmonics Task Force (P1495) is developing a similar standard for single phase loads of less than

Ward Jewell; Daniel J. Ward; Principal Engineer; Dominion Virginia Power

2002-01-01

217

Mathematical modeling and statistical analysis of SPE-OCDMA systems utilizing second harmonic generation effect in thick crystal receivers  

NASA Astrophysics Data System (ADS)

In this paper we analytically study and evaluate the performance of a Spectral-Phase-Encoded Optical CDMA system for different parameters such as the user's code length and the number of users in the network. In this system an advanced receiver structure in which the Second Harmonic Generation effect imposed in a thick crystal is employed as the nonlinear pre-processor prior to the conventional low speed photodetector. We consider ASE noise of the optical amplifiers, effective in low power conditions, besides the multiple access interference (MAI) noise which is the dominant source of noise in any OCDMA communications system. We use the results of the previous work which we analyzed the statistical behavior of the thick crystals in an optically amplified digital lightwave communication system to evaluate the performance of the SPE-OCDMA system with thick crystals receiver structure. The error probability is evaluated using Saddle-Point approximation and the approximation is verified by Monte-Carlo simulation.

Matinfar, Mehdi D.; Salehi, Jawad A.

2009-11-01

218

Harmon Craig (1926-2003)  

NASA Astrophysics Data System (ADS)

Harmon Craig, one of the great pioneers of isotope geochemistry died on 14 March after suffering a massive heart attack at his home in La Jolla, California. He was one day shy of his 77th birthday. Through an academic career of more than fifty years, Craig—or simply “Harmon,” as he was known throughout the world of geochemistry—made a remarkable number of fundamental and far-reaching contributions in a wide range of important areas concerned with the chemical and physical processes by which the solid Earth, the oceans, the atmosphere, and the solar system interact. While his research was broad in scope, it was also characterized by a strong emphasis on meticulous field and laboratory work, and on original and insightful interpretations of the resulting observations.

Weiss, Ray

219

DIII-D physics analysis database  

SciTech Connect

Since June 1986 the DIII-D tokamak has had over 16000 discharges accumulating more than 250 Gigabytes of raw data (currently over 30 Mbytes per discharge). The centralized DIII-D databases and the associated support software described earlier provide the means to extract, analyze, store, and display reduced sets of data for specific physics issues. The confinement, stability, transition, and cleanliness databases consist of more than 7500 records of basic reduced diagnostic data datasets. Each database record corresponds to a specific snapshot in time for a selected discharge. Recently some profile datasets have been implemented. Diagnostic data are fit by a cubic spline or a parabola by the in-house ENERGY code to provide density, temperature, radiated power, effective charge (Z{sub eff}), and rotation velocity profiles. These fits are stored in the profile datasets which are inputs for the ONETWO code which computes transport data. 3 refs., 4 figs.

Bramson, G.; Schissel, D.P.; DeBoo, J.C.; St. John, H.

1990-10-01

220

Multicomponent controllers in reactor physics optimality analysis  

Microsoft Academic Search

An algorithm is developed for the optimality analysis of thermal reactor assemblies with multi-component control vectors. The neutronics of the system under consideration is assumed to be described by the two-group diffusion equations and constraints are imposed upon the state and control variables. It is shown that if the problem is such that the differential and algebraic equations describing the

Aldemir

1978-01-01

221

Covariant harmonic oscillators and coupled harmonic oscillators  

NASA Technical Reports Server (NTRS)

It is shown that the system of two coupled harmonic oscillators shares the basic symmetry properties with the covariant harmonic oscillator formalism which provides a concise description of the basic features of relativistic hadronic features observed in high-energy laboratories. It is shown also that the coupled oscillator system has the SL(4,r) symmetry in classical mechanics, while the present formulation of quantum mechanics can accommodate only the Sp(4,r) portion of the SL(4,r) symmetry. The possible role of the SL(4,r) symmetry in quantum mechanics is discussed.

Han, Daesoo; Kim, Young S.; Noz, Marilyn E.

1995-01-01

222

Simulation of 100-300 GHz solid-state harmonic sources  

NASA Technical Reports Server (NTRS)

Accurate and efficient simulations of the large-signal time-dependent characteristics of second-harmonic Transferred Electron Oscillators (TEO's) and Heterostructure Barrier Varactor (HBV) frequency triplers have been obtained. This is accomplished by using a novel and efficient harmonic-balance circuit analysis technique which facilitates the integration of physics-based hydrodynamic device simulators. The integrated hydrodynamic device/harmonic-balance circuit simulators allow TEO and HBV circuits to be co-designed from both a device and a circuit point of view. Comparisons have been made with published experimental data for both TEO's and HBV's. For TEO's, excellent correlation has been obtained at 140 GHz and 188 GHz in second-harmonic operation. Excellent correlation has also been obtained for HBV frequency triplers operating near 200 GHz. For HBV's, both a lumped quasi-static equivalent circuit model and the hydrodynamic device simulator have been linked to the harmonic-balance circuit simulator. This comparison illustrates the importance of representing active devices with physics-based numerical device models rather than analytical device models.

Zybura, Michael F.; Jones, J. Robert; Jones, Stephen H.; Tait, Gregory B.

1995-01-01

223

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

224

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

225

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

226

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

227

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

228

Present status of JADE's gammagamma-physics analysis  

Microsoft Academic Search

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

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

1980-01-01

229

Study Modules for Calculus-Based General Physics. [Includes Modules 15-17: Gravitation; Simple Harmonic Motion; and Traveling Waves; plus a Partial Derivatives Review].  

ERIC Educational Resources Information Center

This is part of a series of 42 Calculus Based Physics (CBP) modules totaling about 1,000 pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized course in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…

Fuller, Robert G., Ed.; And Others

230

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

231

Second International Workshop on Harmonic Oscillators  

NASA Technical Reports Server (NTRS)

The Second International Workshop on Harmonic Oscillators was held at the Hotel Hacienda Cocoyoc from March 23 to 25, 1994. The Workshop gathered 67 participants; there were 10 invited lecturers, 30 plenary oral presentations, 15 posters, and plenty of discussion divided into the five sessions of this volume. The Organizing Committee was asked by the chairman of several Mexican funding agencies what exactly was meant by harmonic oscillators, and for what purpose the new research could be useful. Harmonic oscillators - as we explained - is a code name for a family of mathematical models based on the theory of Lie algebras and groups, with applications in a growing range of physical theories and technologies: molecular, atomic, nuclear and particle physics; quantum optics and communication theory.

Han, Daesoo (editor); Wolf, Kurt Bernardo (editor)

1995-01-01

232

Harmonic influence lines in structural dynamics calculated by use of Müller-Breslau's theorem  

NASA Astrophysics Data System (ADS)

Müller-Breslau's theorem is formulated and proved for certain linear structures in forced stationary harmonic vibration. The theorem provides the structural analyst with a computationally attractive method for finding, in one and the same calculation, all coefficients (generally complex-valued) describing the influence on a reactive or sectional force in a fixed position by an external harmonic unit load acting in any position. Critical and dimensioning combinations of loads can thereby easily be found. Three numerical examples demonstrate applications to systems that are discrete and continuous, undamped and damped, and finite and infinite. It is shown how a standard computer program for the analysis of beam and frame vibration can be employed to calculate and plot harmonic influence lines by use of the Müller-Breslau technique. Physical experiments based on the same technique are discussed.

Åkesson, B. Å.

1990-10-01

233

Reactor Analysis Support Package (RASP). Volume 4. BWR physics analysis guidelines. Final report  

Microsoft Academic Search

The EPRI Reactor Analysis Support Package (RASP) consists of computer codes and documentation for analyzing reactor physics and thermal-hydraulics problems. The principal applications of these codes involve fuel management, safety analysis for reload submittals and general support for reactor operations. This report explains one aspect of RASP; namely, the reactor physics applications for boiling water reactors. The topics included are

1986-01-01

234

Reactor Analysis Support Package (RASP). Volume 5. PWR physics analysis guidelines. Final report  

Microsoft Academic Search

The EPRI Reactor Analysis Support Package (RASP) consists of computer codes and documentation for analyzing reactor physics and thermal-hydraulics problems. The principal application of these codes involve fuel management, safety analysis for reload submittals, and general support for reactor operations. This report explains one aspect of RASP; namely, the reactor physics applications for pressurized water reactors. The topics included are

D. J. Diamond; R. R. Lee; R. D. Mosteller; P. J. Turinsky

1986-01-01

235

Physics and Physical Oceanography Data Report 2000-1 Analysis of the Mean Circulation in Placentia Bay  

E-print Network

Physics and Physical Oceanography Data Report 2000-1 Analysis of the Mean Circulation in Placentia of Physics and Physical Oeanography Memorial University of Newfoundland St. John's, Newfoundland A1B 3X7 #12 for their support with this work. We also thank Jack Foley for his help in the deployment and recovery

deYoung, Brad

236

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

237

Simple Harmonic Motion  

NSDL National Science Digital Library

This simulation offers two examples of simple harmonic motion, a mass on a spring and a simple pendulum. The applet allows you to adjust variables and observe the effects these changes have on the movement of the systems.

Pfaff, Raman

2008-07-15

238

Mixing physical habitat and streamflow time series analysis  

Microsoft Academic Search

Four observations from two case studies are presented: physical habitat analysis of the Virgin River in southwestern Utah and upper Animas Basin in southwestern Colorado. The Virgin River is usually considered a sand bed river. Cross-sectional measurements, made at three streamflows, show there was considerable change in the channel between the times of the three sets of measurements. First observation:

Robert T. Milhous

2004-01-01

239

Improving neural network models of physical systems through dimensional analysis  

Microsoft Academic Search

The paper presents a technique for generating concise neural network models of physical systems. The neural network models are generated through a two-stage process. The first stage uses information embedded in the dimensions or units in which the data is represented. Dimensional analysis techniques are used initially to make this information explicit, and a limited search in the neural network

David J. Gunaratnam; Taivas Degroff; John S. Gero

2003-01-01

240

Frontiers in Chemical Physics and Analysis Seminar Series  

E-print Network

Frontiers in Chemical Physics and Analysis Seminar Series Water on a Knife-Edge: The Subtle Balance of Forces in Clusters, Ice and Liquid Presented by... Abstract Water has probably been studied more to reproduce the properties of water clusters, ice structures and the bulk liquid, for reasons that are still

241

Disability in Physical Education Textbooks: An Analysis of Image Content  

ERIC Educational Resources Information Center

The aim of this paper is to show how images of disability are portrayed in physical education textbooks for secondary schools in Spain. The sample was composed of 3,316 images published in 36 textbooks by 10 publishing houses. A content analysis was carried out using a coding scheme based on categories employed in other similar studies and adapted…

Taboas-Pais, Maria Ines; Rey-Cao, Ana

2012-01-01

242

Parachute flying physical model and inflation simulation analysis  

Microsoft Academic Search

By means of establishing parachute’s flying physical model, four methods (i.e. tiny segment analysis method, inflating distance method, moment method and simulating canopy shape method) are adopted to analyze and calculate the variations of canopy shape and the parameters of parachute inflation. The results are simply analyzed, and the figures of all the results are compared.

Yihua Cao; Hong Xu

2004-01-01

243

Frontiers in Chemical Physics and Analysis Seminar Series  

E-print Network

Frontiers in Chemical Physics and Analysis Seminar Series A Novel Ultra-Cold Quantum Plasma: From, crystalline, state. A possible pathway towards such a new state of matter is a quantum plasma for which the de long lifetime of milliseconds, and it shows the compressibility of a "sponge like" ultra-soft solid

244

Theory & motivation Physics Analysis Results Summary Scaled momentum distributions of charged  

E-print Network

Theory & motivation Physics Analysis Results Summary Scaled momentum distributions of charged.morris@cern.ch DIS09 29th April 2009 1 / 18 #12;Theory & motivation Physics Analysis Results Summary Talk outline 1 Theoretical framework: The MLLA and LPHD; Physics motivation. 2 Physics Analysis: Analysis strategy; Data

245

Harmonic Oscillators as Bridges between Theories: Einstein, Dirac, and Feynman  

E-print Network

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

Y. S. Kim; Marilyn E. Noz

2004-11-02

246

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

247

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

248

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.  

PubMed

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. PMID:24096066

Renuga, S; Muthu, S

2014-01-24

249

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

250

PHYSICAL REVIEW B 89, 024102 (2014) Ultrafast surface strain dynamics in MnAs thin films observed with second harmonic generation  

E-print Network

PHYSICAL REVIEW B 89, 024102 (2014) Ultrafast surface strain dynamics in MnAs thin films observed strain in 150 and 190-nm thin films of MnAs grown epitaxially on GaAs(001). The p-polarized SHG signal the surface temperature by tens of degrees. For a film at -20 C the strain reaches a minimum value in 10 ps

Van Driel, Henry M.

251

Increasing Physical Activity With Mobile Devices: A Meta-Analysis  

PubMed Central

Background Regular physical activity has established physical and mental health benefits; however, merely one quarter of the U.S. adult population meets national physical activity recommendations. In an effort to engage individuals who do not meet these guidelines, researchers have utilized popular emerging technologies, including mobile devices (ie, personal digital assistants [PDAs], mobile phones). This study is the first to synthesize current research focused on the use of mobile devices for increasing physical activity. Objective To conduct a meta-analysis of research utilizing mobile devices to influence physical activity behavior. The aims of this review were to: (1) examine the efficacy of mobile devices in the physical activity setting, (2) explore and discuss implementation of device features across studies, and (3) make recommendations for future intervention development. Methods We searched electronic databases (PubMed, PsychINFO, SCOPUS) and identified publications through reference lists and requests to experts in the field of mobile health. Studies were included that provided original data and aimed to influence physical activity through dissemination or collection of intervention materials with a mobile device. Data were extracted to calculate effect sizes for individual studies, as were study descriptives. A random effects meta-analysis was conducted using the Comprehensive Meta-Analysis software suite. Study quality was assessed using the quality of execution portion of the Guide to Community Preventative Services data extraction form. Results Four studies were of “good” quality and seven of “fair” quality. In total, 1351 individuals participated in 11 unique studies from which 18 effects were extracted and synthesized, yielding an overall weight mean effect size of g = 0.54 (95% CI = 0.17 to 0.91, P = .01). Conclusions Research utilizing mobile devices is gaining in popularity, and this study suggests that this platform is an effective means for influencing physical activity behavior. Our focus must be on the best possible use of these tools to measure and understand behavior. Therefore, theoretically grounded behavior change interventions that recognize and act on the potential of smartphone technology could provide investigators with an effective tool for increasing physical activity. PMID:23171838

2012-01-01

252

Surface fitting with biharmonic and harmonic models  

NASA Technical Reports Server (NTRS)

The physical and geometric interpretation of a surface fitting technique, multiquadric equations (MQ), is discussed. The relation of this method and its reciprocal form to biharmonic and harmonic techniques respectively, is pointed out. In both forms the solutions may be viewed as being numerical approximations of an integral equation in which an unknown density function is the physical source for disturbing potential (reciprocal-MQ) or elastic displacement (MQ).

Hardy, R. L.

1982-01-01

253

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

254

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

255

The Coupled Harmonic Oscillator: Not Just for Seniors Anymore.  

ERIC Educational Resources Information Center

Presents experiments that use Microcomputer Based Laboratory (MBL) techniques to enable freshmen physics students to investigate complex systems, such as nonlinear oscillators or coupled harmonic oscillators, at a level appropriate for an independent project. (JRH)

Preyer, Norris W.

1996-01-01

256

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

257

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

258

Backscatter analysis of dihedral corner reflectors using physical optics and the physical theory of diffraction  

NASA Technical Reports Server (NTRS)

The backscatter cross-sections of dihedral corner reflectors in the azimuthal plane are presently determined by both physical optics (PO) and the physical theory of diffraction (PTD), yielding results for the vertical and horizontal polarizations. In the first analysis method used, geometrical optics is used in place of PO at initial reflections in order to maintain the planar character of the reflected wave and reduce the complexity of the analysis. In the second method, PO is used at almost every reflection in order to maximize the accuracy of the PTD solution at the expense of a rapid increase in complexity. Induced surface current densities and resulting cross section patterns are illustrated for the two methods.

Griesser, Timothy; Balanis, Constantine A.

1987-01-01

259

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

260

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

2014-11-01

261

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

262

Harmonization of uncertainties of X-ray fluorescence data for PM2.5 air filter analysis.  

PubMed

The U.S. Environmental Protection Agency (EPA)'s PM2.5 Chemical Speciation Network (CSN) and the Interagency Monitoring of Protected Visual Environments (IMPROVE) network use X-ray fluorescence (XRF) analysis to quantify trace elements in samples of fine particles less than 2.5 microns in aerodynamic diameter (PM2.5). Methods for calculating uncertainty values for XRF results vary considerably among laboratories and instrument makes and models. To support certain types of modeling and data analysis, uncertainty estimates are required that are consistent within and between monitoring programs, and that are independent of the laboratories that performed the analyses and the analytical instrumentation used. The goal of this work was to develop a consensus model for uncertainties associated with XRF analysis of PM2.5 filter samples. The following important components of uncertainty are included in the model described herein: variability in peak area, calibration, field sampling, and attenuation of X-ray intensity for light elements. This paper includes a detailed analysis of how attenuation uncertainties for light elements are derived. For the remaining uncertainty components included in the model, an approach and recommendations are presented to ensure that laboratories performing this type of analysis can use similar equations and parameterizations. By applying this uniform approach, it is illustrated how the uncertainties reported by the CSN and IMPROVE network laboratories can be brought into very good agreement. The proposed method is best applied at the time of data generation, but retrospective estimation of uncertainties in existing data-sets is also possible. This paper serves to document the equations used for calculating the uncertainties in speciated PM2.5 data currently being posted on EPA's Air Quality System database for the PM2.5 CSN program. PMID:20222531

Gutknecht, William; Flanagan, James; McWilliams, Andrea; Jayanty, R K M; Kellogg, Robert; Rice, Joann; Duda, Paul; Sarver, Richard H

2010-02-01

263

Theoretical and experimental analysis of the physics of water rockets  

NASA Astrophysics Data System (ADS)

A simple rocket can be made using a plastic bottle filled with a volume of water and pressurized air. When opened, the air pressure pushes the water out of the bottle. This causes an increase in the bottle momentum so that it can be propelled to fairly long distances or heights. Water rockets are widely used as an educational activity, and several mathematical models have been proposed to investigate and predict their physics. However, the real equations that describe the physics of the rockets are so complicated that certain assumptions are usually made to obtain models that are easier to use. These models provide relatively good predictions but fail in describing the complex physics of the flow. This paper presents a detailed theoretical analysis of the physics of water rockets that concludes with the proposal of a physical model. The validity of the model is checked by a series of field tests. The tests showed maximum differences with predictions of about 6%. The proposed model is finally used to investigate the temporal evolution of some significant variables during the propulsion and flight of the rocket. The experience and procedure described in this paper can be proposed to graduate students and also at undergraduate level if certain simplifications are assumed in the general equations.

Barrio-Perotti, R.; Blanco-Marigorta, E.; Fernández-Francos, J.; Galdo-Vega, M.

2010-09-01

264

Characterization of collagen fibers by means of texture analysis of second harmonic generation images using orientation-dependent gray level co-occurrence matrix method  

NASA Astrophysics Data System (ADS)

Collagen is the most prominent protein in the human body, making up 30% of the total protein content. Quantitative studies have shown structural differences between collagen fibers of the normal and diseased tissues, due to the remodeling of the extracellular matrix during the pathological process. The dominant orientation, which is an important characteristic of collagen fibers, has not been taken into consideration for quantitative collagen analysis. Based on the conventional gray level co-occurrence matrix (GLCM) method, the authors proposed the orientation-dependent GLCM (OD-GLCM) method by estimating the dominant orientation of collagen fibers. The authors validated the utility of the OD-GLCM method on second harmonic generation (SHG) microscopic images of tendons from rats with different ages. Compared with conventional GLCM method, the authors' method has not only improved the discrimination between different tissues but also provided additional texture information of the orderliness of collagen fibers and the fiber size. The OD-GLCM method was further applied to the differentiation of the preliminary SHG images of normal and cancerous human pancreatic tissues. The combination of SHG microscopy and the OD-GLCM method might be helpful for the evaluation of diseases marked with abnormal collagen morphology.

Hu, Wenyan; Li, Hui; Wang, Chunyou; Gou, Shanmiao; Fu, Ling

2012-02-01

265

Characterization of collagen fibers by means of texture analysis of second harmonic generation images using orientation-dependent gray level co-occurrence matrix method.  

PubMed

Collagen is the most prominent protein in the human body, making up 30% of the total protein content. Quantitative studies have shown structural differences between collagen fibers of the normal and diseased tissues, due to the remodeling of the extracellular matrix during the pathological process. The dominant orientation, which is an important characteristic of collagen fibers, has not been taken into consideration for quantitative collagen analysis. Based on the conventional gray level co-occurrence matrix (GLCM) method, the authors proposed the orientation-dependent GLCM (OD-GLCM) method by estimating the dominant orientation of collagen fibers. The authors validated the utility of the OD-GLCM method on second harmonic generation (SHG) microscopic images of tendons from rats with different ages. Compared with conventional GLCM method, the authors' method has not only improved the discrimination between different tissues but also provided additional texture information of the orderliness of collagen fibers and the fiber size. The OD-GLCM method was further applied to the differentiation of the preliminary SHG images of normal and cancerous human pancreatic tissues. The combination of SHG microscopy and the OD-GLCM method might be helpful for the evaluation of diseases marked with abnormal collagen morphology. PMID:22463039

Hu, Wenyan; Li, Hui; Wang, Chunyou; Gou, Shanmiao; Fu, Ling

2012-02-01

266

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

267

Univalent ?-Harmonic Mappings  

NASA Astrophysics Data System (ADS)

We study mappings from 2 into 2 whose components are weak solutions to the elliptic equation in divergence form, div (??u)= 0, which we call ?-harmonic mappings. We prove sufficient conditions for the univalence, i.e., injectivity, of such mappings. Moreover we prove local bounds in BMO on the logarithm of the Jacobian determinant of such univalent mappings, thus obtaining the a.e. nonvanishing of their Jacobian. In particular, our results apply to ?-harmonic mapping associated with any periodic structure and therefore they play an important role in homogenization.

Alessandrini, Giovanni; Nesi, Vincenzo

268

Harmonic Analysis of the Fluorescence Response of Bimane Adducts of Colicin E1 at Helices 6, 7, and 10*  

PubMed Central

The pre-channel state of helices 6, 7, and 10 (Val447–Gly475 and Ile508–Ile522) of colicin E1 was investigated by a site-directed fluorescence labeling technique. A total of 44 cysteine variants were purified and covalently labeled with monobromobimane fluorescent probe. A variety of fluorescence properties of the bimane fluorophore were measured for both the soluble and membrane-bound states of the channel peptide, including the fluorescence emission maximum, fluorescence anisotropy, and membrane bilayer penetration depth. Using site-directed fluorescence labeling combined with our novel helical periodicity analysis method, the data revealed that helices 6, 7, and 10 are separate amphipathic ?-helices with a calculated periodicity of T = 3.34 ± 0.08 for helix 6, T = 3.56 ± 0.03 for helix 7, and T = 2.99 ± 0.12 for helix 10 in the soluble state. In the membrane-bound state, the helical periodicity was determined to be T = 3.00 ± 0.15 for helix 6, T = 3.68 ± 0.03 for helix 7, and T = 3.47 ± 0.04 for helix 10. Dual fluorescence quencher analysis showed that both helices 6 and 7 adopt a tilted topology that correlates well with the analysis based on the fluorescence anisotropy profile. These data provide further support for the umbrella model of the colicin E1 channel domain. PMID:23264635

Ho, Derek; Lugo, Miguel R.; Merrill, A. Rod

2013-01-01

269

Real time digital harmonic modeling and simulation: an advanced tool for understanding power system harmonics mechanisms  

Microsoft Academic Search

Off-line computation and sometimes full transient time domain simulation has been the tool of choice for modeling power system harmonic phenomena in the past. Due to significant advances in real-time digital network simulation technologies, both in decreasing time step size and increased model complexity, this tool becomes more attractive for advanced harmonic analysis. This paper proposes the use of hardware-in-loop

M. Steurer; S. Woodruff

2004-01-01

270

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

271

Meta-Analysis of Workplace Physical Activity Interventions  

PubMed Central

Context Most adults do not achieve adequate physical activity. Despite the potential benefits of worksite health promotion, no previous comprehensive meta-analysis has summarized health and physical activity behavior outcomes from these programs. This comprehensive meta-analysis integrated the extant wide range of worksite physical activity intervention research. Evidence acquisition Extensive searching located published and unpublished intervention studies reported from 1969 through 2007. Results were coded from primary studies. Random-effects meta-analytic procedures, including moderator analyses, were completed in 2008. Evidence synthesis Effects on most variables were substantially heterogeneous because diverse studies were included. Standardized mean difference (d) effect sizes were synthesized across approximately 38,231 subjects. Significantly positive effects were observed for physical activity behavior (0.21), fitness (0.57), lipids (0.13), anthropometric measures (0.08), work attendance (0.19), and job stress (0.33). The significant effect size for diabetes risk (0.98) is more tentative given small sample sizes. Significant heterogeneity documents intervention effects varied across studies. The mean effect size for fitness corresponds to a difference between treatment minus control subjects' means on V02max of 3.5 mL/kg/min; for lipids, ?0.2 on total cholesterol:HDL; and for diabetes risk, ?12.6 mg/dL on fasting glucose. Conclusions These findings document that some workplace physical activity interventions can improve both health and important worksite outcomes. Effects were variable for most outcomes, reflecting the diversity of primary studies. Future primary research should compare interventions to confirm causal relationships and further explore heterogeneity. PMID:19765506

Conn, Vicki S.; Hafdahl, Adam R.; Cooper, Pamela S.; Brown, Lori M.; Lusk, Sally L.

2009-01-01

272

Harmonic Superspaces of Extended Supersymmetry. The Calculus of Harmonic Variables.  

National Technical Information Service (NTIS)

The main technical apparatus of the harmonic superspace approach to extended SUSY, the calculus of harmonic variables on homogeneous spaces of the SUSY automorphism groups, is presented in detail for N=2, 3, 4. The basic harmonics for the coset manifolds ...

E. Ivanov, S. Kalitzin Nguyen Ai Viet, V. Ogievetsky

1984-01-01

273

Introducing Simple Harmonic Motion.  

ERIC Educational Resources Information Center

Explains the origin and significance of harmonic motion which is an important topic that has wide application in the world. Describes the phenomenon by using an auxiliary circle to help illustrate the key relationships between acceleration, displacement, time, velocity, and phase. (Contains 16 references.) (Author/YDS)

Roche, John

2002-01-01

274

A harmonic motion experiment  

NASA Astrophysics Data System (ADS)

We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions.

Gluck, P.; Krakower, Zeev

2010-11-01

275

Fault detection and diagnostics for non-intrusive monitoring using motor harmonics  

Microsoft Academic Search

Harmonic analysis of motor current has been used to track the speed of motors for sensorless control. Algorithms exist that track the speed of a motor given a dedicated stator current measurement, for example. Harmonic analysis has also been applied for diagnostic detection of electro-mechanical faults such as damaged bearings and rotor eccentricity. This paper demonstrates the utility of harmonic

Uzoma A. Orji; Z. Remscrim; C. Laughman; S. B. Leeb; W. Wichakool; C. Schantz; R. Cox; J. L. Kirtley; L. K. Norford

2010-01-01

276

The time-dependent quantum harmonic oscillator revisited: Applications to quantum field theory  

SciTech Connect

In this article, we formulate the study of the unitary time evolution of systems consisting of an infinite number of uncoupled time-dependent harmonic oscillators in mathematically rigorous terms. We base this analysis on the theory of a single one-dimensional time-dependent oscillator, for which we first summarize some basic results concerning the unitary implementability of the dynamics. This is done by employing techniques different from those used so far to derive the Feynman propagator. In particular, we calculate the transition amplitudes for the usual harmonic oscillator eigenstates and define suitable semiclassical states for some physically relevant models. We then explore the possible extension of this study to infinite dimensional dynamical systems. Specifically, we construct Schroedinger functional representations in terms of appropriate probability spaces, analyze the unitarity of the time evolution, and probe the existence of semiclassical states for a wide range of physical systems, particularly, the well-known Minkowskian free scalar fields and Gowdy cosmological models.

Gomez Vergel, Daniel [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain)], E-mail: dgvergel@iem.cfmac.csic.es; Villasenor, Eduardo J.S. [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Grupo de Modelizacion y Simulacion Numerica, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes (Spain)], E-mail: ejsanche@math.uc3m.es

2009-06-15

277

Fault Detection and Diagnostics for Non-Intrusive Monitoring Using Motor Harmonics  

E-print Network

Harmonic analysis of motor current has been used to track the speed of motors for sensorless control. Algorithms exist that track the speed of a motor given a dedicated stator current measurement, for example. Harmonic ...

Orji, Uzoma A.

278

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

279

Disability in physical education textbooks: an analysis of image content.  

PubMed

The aim of this paper is to show how images of disability are portrayed in physical education textbooks for secondary schools in Spain. The sample was composed of 3,316 images published in 36 textbooks by 10 publishing houses. A content analysis was carried out using a coding scheme based on categories employed in other similar studies and adapted to the requirements of this study with additional categories. The variables were camera angle, gender, type of physical activity, field of practice, space, and level. Univariate and bivariate descriptive analyses were also carried out. The Pearson chi-square statistic was used to identify associations between the variables. Results showed a noticeable imbalance between people with disabilities and people without disabilities, and women with disabilities were less frequently represented than men with disabilities. People with disabilities were depicted as participating in a very limited variety of segregated, competitive, and elite sports activities. PMID:23027145

Táboas-Pais, María Inés; Rey-Cao, Ana

2012-10-01

280

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

281

Positioning Ideas: Creating and Relating Physics Identities Through Video Analysis  

NSDL National Science Digital Library

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; Swanson, Lauren

2010-01-19

282

Automatic Semantic Annotation of Music with Harmonic Structure  

E-print Network

scenarios in music production, education, and retrieval and in musicology. Keywords--harmonic analysis for applications in musicology, music education, and music information retrieval. Music theorists often speakAutomatic Semantic Annotation of Music with Harmonic Structure Tillman Weyde, Jens Wissmann Music

Kouroupetroglou, Georgios

283

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

284

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, 08543-451 Many problems in plasma physics involve to their problems. Several applications of this symbolic vector analysis package to plasma physics are also given

285

Adjoint Sensitivity Analysis of Orbital Mechanics: Application to Computations of Observables' Partials with Respect to Harmonics of the Planetary Gravity Fields  

NASA Technical Reports Server (NTRS)

An approach is presented to the inversion of gravity fields based on evaluation of partials of observables with respect to gravity harmonics using the solution of adjoint problem of orbital dynamics of the spacecraft. Corresponding adjoint operator is derived directly from the linear operator of the linearized forward problem of orbital dynamics. The resulting adjoint problem is similar to the forward problem and can be solved by the same methods. For given highest degree N of gravity harmonics desired, this method involves integration of N adjoint solutions as compared to integration of N2 partials of the forward solution with respect to gravity harmonics in the conventional approach. Thus, for higher resolution gravity models, this approach becomes increasingly more effective in terms of computer resources as compared to the approach based on the solution of the forward problem of orbital dynamics.

Ustinov, Eugene A.; Sunseri, Richard F.

2005-01-01

286

Theoretical analysis of the effect of coating polarization on the second harmonic generation of an Nd:YVO4/KTP laser  

NASA Astrophysics Data System (ADS)

Jones calculus is used to analyze the effect of the polarization characteristics of the output mirror coating of a V-shaped Nd:YVO4/KTP laser on the second harmonic generation. The reflection-induced phase retardance (RIPR) of the coating can quench the second harmonic generation. When the optical axis of Nd:YVO4 makes a ?/4 angle with the incident plane of the output mirror and the fast axis of KTP in the incident plane, the RIPR induced reduction of coupling factor of the second harmonic generation is less than 1% if the phase retardance is smaller than 25°. If the polarization direction of the fundamental wave coincides with the eigen-polarization directions of the incident plane, the effect of the reflection-induced phase retardance on the conversing efficiency can be avoided.

Wang, Xiaozhong; Ma, Zhen; Huang, Chaohong; Chen, Lujian; Bu, Yikun

2011-10-01

287

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

288

Management of the Space Physics Analysis Network (SPAN)  

NASA Technical Reports Server (NTRS)

Here, the purpose is to define the operational management structure and to delineate the responsibilities of key Space Physics Analysis Network (SPAN) individuals. The management structure must take into account the large NASA and ESA science research community by giving them a major voice in the operation of the system. Appropriate NASA and ESA interfaces must be provided so that there will be adequate communications facilities available when needed. Responsibilities are delineated for the Advisory Committee, the Steering Committee, the Project Scientist, the Project Manager, the SPAN Security Manager, the Internetwork Manager, the Network Operations Manager, the Remote Site Manager, and others.

Green, James L.; Thomas, Valerie L.; Butler, Todd F.; Peters, David J.; Sisson, Patricia L.

1990-01-01

289

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

290

New Directions for Physics Education Research: A Broad Perspective Analysis  

NSDL National Science Digital Library

In this paper we introduce a framework that can be used to categorize instructional practices. We then use this framework to identify areas where mainstream Physics Education Research (PER) has embraced alternative ideas and areas where mainstream PER is more traditional. As an example we argue that while PER has embraced the practice of interactivity, it has neglected the practice of student autonomy. This is despite student autonomy being consistent with the goals of PER and being supported by research in other fields. We offer insights and implications based on this analysis.

Dancy, Melissa H.; Henderson, Charles R.

2009-07-13

291

Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-ray Free Electron Lasers  

SciTech Connect

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.

Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodle, M.; /SLAC; ,

2012-02-15

292

Point-based manifold harmonics.  

PubMed

This paper proposes an algorithm to build a set of orthogonal Point-Based Manifold Harmonic Bases (PB-MHB) for spectral analysis over point-sampled manifold surfaces. To ensure that PB-MHB are orthogonal to each other, it is necessary to have symmetrizable discrete Laplace-Beltrami Operator (LBO) over the surfaces. Existing converging discrete LBO for point clouds, as proposed by Belkin et al., is not guaranteed to be symmetrizable. We build a new point-wisely discrete LBO over the point-sampled surface that is guaranteed to be symmetrizable, and prove its convergence. By solving the eigen problem related to the new operator, we define a set of orthogonal bases over the point cloud. Experiments show that the new operator is converging better than other symmetrizable discrete Laplacian operators (such as graph Laplacian) defined on point-sampled surfaces, and can provide orthogonal bases for further spectral geometric analysis and processing tasks. PMID:22879345

Liu, Yang; Prabhakaran, Balakrishnan; Guo, Xiaohu

2012-10-01

293

Spherical Harmonics YLM Explorer  

NSDL National Science Digital Library

This is a Java applet that creates surface plots of the spherical harmonics. The user can set the L and m indices and the resolution of the plot. There is a restriction that L must be less than or equal to 5. Results are shown as either the amplitude of the function colored by the complex phase or the real part of the function illuminated by an external light source. Plots may be rotated in three dimensions.

Kraus, Martin

2005-04-16

294

Computing prime harmonic sums  

NASA Astrophysics Data System (ADS)

We discuss a method for computing sum_{p le x} 1/p , using time about x^{2/3} and space about x^{1/3} . It is based on the Meissel-Lehmer algorithm for computing the prime-counting function pi(x) , which was adapted and improved by Lagarias, Miller, and Odlyzko. We used this algorithm to determine the first point at which the prime harmonic sum first crosses 4.

Bach, Eric; Klyve, Dominic; Sorenson, Jonathan P.

2009-12-01

295

Metrics with harmonic spinors  

Microsoft Academic Search

We show that every closed spin manifold of dimensionn ? 3 mod 4 with a fixed spin structure can be given a Riemannian metric with harmonic spinors, i.e. the corresponding Dirac operator has a non-trivial kernel (Theorem A). To prove this we first compute the Dirac spectrum of the Berger spheresSn,n odd (Theorem 3.1). The second main ingredient is Theorem

Christian Bär

1996-01-01

296

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

297

Tracking harmonic notch filter  

SciTech Connect

An electronic filter for automatically tracking and removing harmonically related interfering electrical signals such as power-line interference harmonics without attenuating other signals of interest even though the signals are frequency stable and/or near the interference signal frequencies. The filter comprises a very narrow band electronic commutated capacitor-bank comb-notch filter driven by a counter/decoder circuit which is in turn driven by a phase locked loop. The filter also comprises two narrow-band analog filters tuned to the two lowest harmonics of the interfering signal. The summed output of these two filters is applied to the input of the phase-locked loop. The phase-locked loop locks to the proper multiple of the interfering signal and drives the comb notch filter at a frequency which causes it to generate notches at unit multiples of the fundamental of the interference frequency. This action is continuous such that center frequencies of the notches are automatically adjusted to compensate for small variations in the interference frequency.

Eno, F.

1989-03-20

298

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

299

Frequencies of standing Alfvén wave harmonics and their implication for plasma mass distribution along geomagnetic field lines: Statistical analysis of CRRES data  

Microsoft Academic Search

The relationship among the frequencies of the harmonics of standing Alfvén waves depends on the variation of plasma mass density along the geomagnetic field line. This in turn means that observed standing wave frequencies may be used to infer the mass density variation, which is difficult to measure with particle instruments on spacecraft. Determination of the density variation is important

Kazue Takahashi; Richard E. Denton; Roger R. Anderson; W. Jeffrey Hughes

2004-01-01

300

Geometry, Physics, and Harmonic Functions Robert Huffaker  

E-print Network

is a language of rigor and clarity. A plethora of symbols and words litter every student's math textbooks(c). This formula for T(a) was an important result that drew attention (and controversy) from a veritable all

Morrow, James A.

301

Core loss prediction combining physical models with numerical field analysis  

NASA Astrophysics Data System (ADS)

An improved procedure for calculating iron losses in electrical machine cores is presented. It is based on physical models and experiments on losses in magnetic laminations, under one- and two-dimensional fields, and exploits a finite element computation of the flux distribution in the core. Physical modelling relies on the basic concept of loss separation, extended to the case of vectorial magnetic flux with generic elliptical loci. Starting from a theoretical formulation of power losses under unidirectional fields and generic induction waveform and its extension to the case of elliptical flux, general expressions are derived for the hysteresis, excess and classical loss components in two dimensions. Quasi-static and 50 Hz total losses under alternating sinusoidal flux and pure rotational flux are the sole experimental data needed for a complete loss prediction. In the present work, two different types of nonoriented FeSi 3.2% laminations are considered, which are assumed to be assembled into a model three-phase motor core. By means of a 2D finite element analysis, the distribution of magnetic field and induction in the core is obtained for different values of the supply current and the loss calculation is carried out. A comparison with standard loss calculation methods points to the detrimental role of two-dimensional fluxes, although this may not be fully appreciated in conventional 50 Hz induction motors.

Bertotti, G.; Canova, A.; Chiampi, M.; Chiarabaglio, D.; Fiorillo, F.; Rietto, A. M.

1994-05-01

302

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

303

Fourier analysis of thermal diffusive waves  

NASA Astrophysics Data System (ADS)

We present details of an experiment that improves earlier attempts to study the propagation of diffusive thermal waves inside a metal rod. In addition to technical improvements in data acquisition and heater control, the experiment physically illustrates insightful concepts in Fourier analysis. For example, the harmonic content and the differential damping of harmonics can be observed in the thermal domain, thus providing a valuable extension to the standard Fourier analysis of electric circuits.

Sabieh Anwar, Muhammad; Alam, Junaid; Wasif, Muhammad; Ullah, Rafi; Shamim, Sohaib; Zia, Wasif

2014-10-01

304

Damped Driven Harmonic Oscillator Phasor Model  

NSDL National Science Digital Library

The Ejs Damped Driven Harmonic Oscillator Phasor model displays the motion of damped driven harmonic oscillator. The resulting differential equation can be extended into the complex plane, and the resulting complex solution is displayed with the real part of this solution being the position of the oscillator. The natural frequency of the oscillator, the damping coefficient, and the driving force and driving frequency can be changed via textboxes. 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 Damped Driven Harmonic Oscillator Phasor 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_phasors.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

305

Damped quantum harmonic oscillator  

E-print Network

In the framework of the Lindblad theory for open quantum systems the damping of the harmonic oscillator is studied. A generalization of the fundamental constraints on quantum mechanical diffusion coefficients which appear in the master equation for the damped quantum oscillator is presented; the Schr\\"odinger and Heisenberg representations of the Lindblad equation are given explicitly. On the basis of these representations it is shown that various master equations for the damped quantum oscillator used in the literature are particular cases of the Lindblad equation and that the majority of these equations are not satisfying the constraints on quantum mechanical diffusion coefficients. Analytical expressions for the first two moments of coordinate and momentum are also obtained by using the characteristic function of the Lindblad master equation. The master equation is transformed into Fokker-Planck equations for quasiprobability distributions. A comparative study is made for the Glauber $P$ representation, the antinormal ordering $Q$ representation and the Wigner $W$ representation. It is proven that the variances for the damped harmonic oscillator found with these representations are the same. By solving the Fokker-Planck equations in the steady state, it is shown that the quasiprobability distributions are two-dimensional Gaussians with widths determined by the diffusion coefficients. The density matrix is represented via a generating function, which is obtained by solving a time-dependent linear partial differential equation derived from the master equation. Illustrative examples for specific initial conditions of the density matrix are provided.

A. Isar; A. Sandulescu

2006-02-17

306

DEPARTMENT OF PHYSICS Physics 20300  

E-print Network

therapy) and for liberal arts students. Fundamental ideas and laws of physics from mechanics to modern and dynamics 7. understand the fundamentals of simple harmonic motion 8. understand the properties of fluids 9 at an appropriate introductory level in important fields of classical physics, including mechanics, electricity

Lombardi, John R.

307

Physical and Chemical Analytical Analysis: A key component of Bioforensics  

SciTech Connect

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, trace element, isotopic, and other molecular ''fingerprints'' of the agent that may be key pieces of evidence, supplementing that obtained from genetic analysis or other biological properties. The generation and interpretation of such data represents a new domain of forensic science, closely aligned with other areas of ''microbial forensics''. This paper describes some major elements of the R&D agenda that will define this sub-field in the immediate future and provide the foundations for a coherent national capability. Data from chemical and physical analysis of BW materials can be useful to an investigation of a bio-terror event in two ways. First, it can be used to compare evidence samples collected at different locations where such incidents have occurred (e.g. between the powders in the New York and Washington letters in the Amerithrax investigation) or between the attack samples and those seized during the investigation of sites where it is suspected the material was manufactured (if such samples exist). Matching of sample properties can help establish the relatedness of disparate incidents, and mis-matches might exclude certain scenarios, or signify a more complex etiology of the events under investigation. Chemical and morphological analysis for sample matching has a long history in forensics, and is likely to be acceptable in principle in court, assuming that match criteria are well defined and derived from known limits of precision of the measurement techniques in question. Thus, apart from certain operational issues (such as how to prioritize such measurements in the face of limited sample availability, or how to render samples safe for handling in the analytical laboratory,) instrumental analysis of biological agents for purposes of sample matching alone is unlikely to present fundamental problems that require extensive research and development investments. The second way that the data generated by instrumental analysis can be useful to an investigation is through inferences that can be drawn regarding the processes used to grow and ''weaponize'' the agent. In contrast to the case of sample matching, there are significant R&D challenges associated with developing a robust capability that will reliably permit such inferential uses of instrumental data. Elaborating these challenges occupies the major portion of this paper.

Velsko, S P

2005-02-15

308

Physics analysis of the ITER ECW system for optimized performance  

NASA Astrophysics Data System (ADS)

A predictive analysis of the capabilities of the ITER electron cyclotron wave system is presented in this work. Modifications of both the upper launcher and the equatorial launcher aimed at increasing the potentialities of the system are identified and discussed. A modification of the upper launcher has already been incorporated in the updated front steering design called the extended physics launcher. By adopting different deposition ranges for the upper and lower steering mirrors, this design offers the flexibility to drive current from the radial region required for the stabilization of neoclassical tearing modes (NTM) up to that required for sawtooth control, allowing a synergy with the equatorial launcher. Here a comparison of the performance of the new design of the upper launcher with those of a dropped upper launcher is performed, showing that better performance for both NTM stabilization and sawtooth control may be obtained by lowering the upper port location. An analysis of the EC current driven by the equatorial launcher is also presented, showing that adding to the present design the possibility to drive counter-current in addition to the existing co-current capability would increase the flexibility of the system. The behaviour of all launchers at reduced magnetic fields is also discussed.

Ramponi, G.; Farina, D.; Henderson, M. A.; Poli, E.; Sauter, O.; Saibene, G.; Zohm, H.; Zucca, C.

2008-05-01

309

Cardiovascular risk profile: Cross-sectional analysis of motivational determinants, physical fitness and physical activity  

Microsoft Academic Search

BACKGROUND: Cardiovascular risk factors are associated with physical fitness and, to a lesser extent, physical activity. Lifestyle interventions directed at enhancing physical fitness in order to decrease the risk of cardiovascular diseases should be extended. To enable the development of effective lifestyle interventions for people with cardiovascular risk factors, we investigated motivational, social-cognitive determinants derived from the Theory of Planned

Barbara Sassen; Gerjo Kok; Herman Schaalma; Henri Kiers; Luc Vanhees

2010-01-01

310

Coupled oscillators, entangled oscillators, and Lorentz-covariant harmonic oscillators  

E-print Network

Other than scattering problems where perturbation theory is applicable, there are basically two ways to solve problems in physics. One is to reduce the problem to harmonic oscillators, and the other is to formulate the problem in terms of two-by-two matrices. If two oscillators are coupled, the problem combines both two-by-two matrices and harmonic oscillators. This method then becomes a powerful research tool to cover many different branches of physics. Indeed, the concept and methodology in one branch of physics can be translated into another through the common mathematical formalism. Coupled oscillators provide clear illustrative examples for some of the current issues in physics, including entanglement and Feynman's rest of the universe. In addition, it is noted that the present form of quantum mechanics is largely a physics of harmonic oscillators. Special relativity is the physics of the Lorentz group which can be represented by the group of two-by-two matrices commonly called $SL(2,c)$. Thus the coupled harmonic oscillators can play the role of combining quantum mechanics with special relativity. It is therefore possible to relate the current issues of physics to the Lorentz-covariant formulation of quantum mechanics.

Y. S. Kim; Marilyn E. Noz

2005-02-15

311

Descriptive Analysis of Physical Activity Conversations on Twitter  

E-print Network

, and captured metadata associated with muscle-strengthening, aerobic, and flexibility- enhancing physical blog, physical activity ACM Classification Keywords J.3 Life and Medical Sciences (Health), J.4 Social

Pratt, Wanda

312

Physical Disability on Children's Television Programming: A Content Analysis  

ERIC Educational Resources Information Center

Research Findings: Media representations of physical disability can influence the attitudes of child audiences. In the current study, the depiction of physical disability was analyzed in more than 400 episodes of children's television programming to better understand how media depict physical disability to children and, in turn, how exposure may…

Bond, Bradley J.

2013-01-01

313

A social network analysis of research collaboration in physics education  

Microsoft Academic Search

Based on the author indices over the past ten years in three international journals of physics teaching, we have constructed networks of physics educators. The latter are connected if they have published one or more articles together in any one of the three journals. We obtained some important sociological characteristics of the research collaborations or linkages between physics teachers. These

Yau-Yuen Yeung; Timon Cheng-Yi Liu; Pun-Hon Ng

2005-01-01

314

Re-conceiving ability in physical education: a social analysis  

Microsoft Academic Search

In this paper we explore how ‘ability’ is currently conceptualised in physical education and with what effects for different groups of young people. We interrogate approaches to theorising ability in physical education that draw on sociological and phenomenological ‘foundations’ together with notions of ability as ‘physical’ and ‘cultural capital’ drawn from the work of Bourdieu. We also look to data

Jan Wright; Lisette Burrows

2006-01-01

315

Re-Conceiving Ability in Physical Education: A Social Analysis  

ERIC Educational Resources Information Center

In this paper we explore how "ability" is currently conceptualised in physical education and with what effects for different groups of young people. We interrogate approaches to theorising ability in physical education that draw on sociological and phenomenological "foundations" together with notions of ability as "physical" and "cultural capital"…

Wright, Jan; Burrows, Lisette

2006-01-01

316

Number of Women in Physics Departments: A Simulation Analysis. Report  

ERIC Educational Resources Information Center

Women's representation in physics lags behind most other STEM disciplines. Currently, women make up about 13% of faculty members in all physics degree-granting departments, and there are physics departments with no women faculty members at all. These two data points are often cited as evidence of a lack of equity for women. In this article,…

White, Susan; Ivie, Rachel

2013-01-01

317

Harmonic spinors on Riemann surfaces  

Microsoft Academic Search

We calculate the dimension of the space of harmonic spinors on hyperelliptic Riemann surfaces for all spin structures. Furthermore, we present non-hype relliptic examples of genus 4 and 6 on which the maximal possible number of linearly independent harmonic spinors is achieved.

Christian Bär; Paul Schmutz

1992-01-01

318

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

319

MODEL HARMONIZATION POTENTIAL AND BENEFITS  

EPA Science Inventory

The IPCS Harmonization Project, which is currently ongoing under the auspices of the WHO, in the context of chemical risk assessment or exposure modeling, does not imply global standardization. Instead, harmonization is thought of as an effort to strive for consistency among appr...

320

Galilean covariant harmonic oscillator  

NASA Technical Reports Server (NTRS)

A Galilean covariant approach to classical mechanics of a single particle is described. Within the proposed formalism, all non-covariant force laws defining acting forces which become to be defined covariantly by some differential equations are rejected. Such an approach leads out of the standard classical mechanics and gives an example of non-Newtonian mechanics. It is shown that the exactly solvable linear system of differential equations defining forces contains the Galilean covariant description of harmonic oscillator as its particular case. Additionally, it is demonstrated that in Galilean covariant classical mechanics the validity of the second Newton law of dynamics implies the Hooke law and vice versa. It is shown that the kinetic and total energies transform differently with respect to the Galilean transformations.

Horzela, Andrzej; Kapuscik, Edward

1993-01-01

321

Anxiety Outcomes after Physical Activity Interventions: Meta-Analysis Findings  

PubMed Central

Background Although numerous primary studies have documented the mental health benefits of physical activity (PA), no previous quantitative synthesis has examined anxiety outcomes of interventions to increase PA. Objectives This meta-analysis integrates extant research about anxiety outcomes from interventions to increase PA among healthy adults. Method Extensive literature searching located published and unpublished PA intervention studies with anxiety outcomes. Eligible studies reported findings from interventions designed to increase PA delivered to healthy adults without anxiety disorders. Data were coded from primary studies. Random-effects meta-analytic procedures were completed. Exploratory moderator analyses using meta-analysis ANOVA and regression analogues were conducted to determine if report, methods, sample, or intervention characteristics were associated with differences in anxiety outcomes. Results Data were synthesized across 3,289 subjects from 19 eligible reports. The overall mean anxiety effect size (d-index) for two-group comparisons was 0.22 with significant heterogeneity (Q = 32.15). Exploratory moderator analyses found larger anxiety improvement effect sizes among studies that included larger samples, used random allocation of subjects to treatment and control conditions, targeted only PA behavior instead of multiple health behaviors, included supervised exercise (vs. home-based PA), used moderate or high-intensity instead of low-intensity PA, and suggested subjects exercise at a fitness facility (vs. home) following interventions. Discussion These findings document that some interventions can decrease anxiety symptoms among healthy adults. Exploratory moderator analyses suggest possible directions for future primary research to compare interventions in randomized trials to confirm causal relationships. PMID:20410849

Conn, Vicki S.

2011-01-01

322

Harmonics and instabilities in switching circuits  

SciTech Connect

Over the last couple of years there has been significant activity in the development of Flexible AC Transmission Systems (FACTS). Much of this work has been directed towards advanced series compensation (ASC) systems based on a Thyristor Controlled Reactor (TCR) connected in parallel with a fixed capacitor. This results in a controllable series impedance element for use in transmission systems. FACTS devices generate harmonics which interact with the transmission system causing voltage distortions. These distortions can change the operation of such circuits. The authors have found new instabilities in both FACTS and static VAR circuits in which switching times change suddenly, or bifurcate as a system parameter varies slowly. The switching time bifurcation instabilities are explained and their mechanisms are illustrated by both analysis and simulation. The TCR is a periodically operated, nonlinear circuit which may be studied using a Poincare map. The Poincare map is computed and a simple formula for its Jacobian matrix is derived. This formula which describes the stability of the steady state periodic operation of the circuit is used to demonstrate that conventional bifurcations do not occur in this TCR example. The harmonic coupling solution method as developed by Bohmann and Lasseter has been extensively used to compute the steady state solutions of the TCR circuits. In this method, Fourier techniques are used to calculate the system harmonics. By expressing the TCR voltage and current as a Fourier series, a TCR harmonic admittance matrix is constructed and incorporated into a power system providing a general method of computing the power system harmonics. The authors have extended this method to single phase line commutated converters and shown how much circuit may have highly nonlinear and unexpected behavior.

Lasseter, R.H.; Dobson, I.; Jalali, S.G. (Univ. of Wisconsin, Madison, WI (United States). Coll. of Engineering)

1993-05-01

323

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

324

Teaching nature of physics in French high schools keywords : teaching, NOS, physics, video analysis  

E-print Network

Teaching nature of physics in French high schools keywords : teaching, NOS, physics, video, 1989; Lederman, 1992). Those findings justify the research on NOS teaching within institutional, 1993) provide a place for NOS in the curriculum as teaching content from kindergarten to high school

Boyer, Edmond

325

Effects of Physical Exercise on Autism Spectrum Disorders: A Meta-Analysis  

ERIC Educational Resources Information Center

It is generally agreed that regular physical exercise promotes physical and mental health, but what are the benefits in people with Autism Spectrum Disorders (ASD)? This meta-analysis evaluates 16 behavioural studies reporting on a total of 133 children and adults with various variants of the syndrome who were offered structured physical…

Sowa, Michelle; Meulenbroek, Ruud

2012-01-01

326

Efficient modeling of the earth's magnetic field with harmonic splines  

Microsoft Academic Search

The geophysical method of harmonic splines produces magnetic field models at th5 core surface which are maximally smooth to the extent that they minimize certain special norms, and do not exhibit the highly oscillatory fields generated by models derived from a least-square analysis with a truncated sphe5ical harmonic series. Such modeling, however, calls for the solution of a square system

R. L. Parker; Loren Shure

1982-01-01

327

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

328

Applying Cluster Analysis to Physics Education Research Data  

ERIC Educational Resources Information Center

One major thrust of Physics Education Research (PER) is the identification of student ideas about specific physics concepts, both correct ideas and those that differ from the expert consensus. Typically the research process of eliciting the spectrum of student ideas involves the administration of specially designed questions to students. One major…

Springuel, R. Padraic

2010-01-01

329

A Kinetic Structural Analysis of Some College Physics Lectures.  

ERIC Educational Resources Information Center

This study was proposed to determine the occurrence, stability, and character of kinetic structure patterns within college physics lessons. Six lectures were randomly chosen from the schedules of each of six cooperating physics professors and a transcription of audio-tape recordings of each lecture was prepared. The flow of discourse was broken…

Sharp, William Legg, Jr.

330

A Meta-Analysis of College Students' Physical Activity Behaviors  

Microsoft Academic Search

The authors reviewed studies on college students' physical activity (PA) behaviors and found that previous research on this topic focused on describing college students' PA patterns and their determinants. Researchers reported that about 40% to 50% of college students are physically inactive. More important, health and PA professionals in higher education have not been able to effectively increase students' PA

Xiaofen Deng Keating; Jianmin Guan; José Castro Piñero; Dwan Marie Bridges

2005-01-01

331

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

332

Numerical study of deformation-induced fluid flows in periodic osteonal matrix under harmonic axial loading  

NASA Astrophysics Data System (ADS)

Living bone is a tissue that is constantly renewed. It has been demonstrated that bone fluid flow and induced shear effects on the bone cells are important players in triggering and signaling bone formation and remodelling. This Note presents a model studying interstitial fluid flow in cortical bone under axial harmonic loads. These living tissues are considered as saturated anisotropic poroelastic material characterized by three-dimensional periodic groups of osteons. Using a frequency-domain analysis, the fluid shear stress variations are studied for various loading conditions and geometrical or physical bone matrix parameters. To cite this article: V.-H. Nguyen et al., C. R. Mecanique 337 (2009).

Nguyen, Vu-Hieu; Lemaire, Thibault; Naili, Salah

2009-05-01

333

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

334

Physics.  

ERIC Educational Resources Information Center

The author presents the argument that the past few years, in terms of new discoveries, insights, and questions raised, have been among the most productive in the history of physics. Selected for discussion are some of the most important new developments in physics research. (Author/SA)

Bromley, D. Allan

1980-01-01

335

Physics  

Microsoft Academic Search

Nuclear, plasma, elementary particle, and atomic and molecular physics are surveyed along with the physics of condensed matter and relativistic astrophysics. Attention is given to the discovery of quarks, psi particles, bosons and nuclear quantum states, the role of group theory and the search for a unified field theory. Also considered are magnetic and inertial confinement regarding fusion power, and

D. A. Bromley

1980-01-01

336

Real-Time Digital Time-Varying Harmonic Modeling and Simulation Techniques IEEE Task Force on Harmonics Modeling and Simulation  

Microsoft Academic Search

With the growing importance of power quality problems to electric utilities and customers, there is an increased focus on the search for new tools and techniques for accurate analysis and resolution of such problems. This paper reviews currently available techniques for the modeling and simulation of time-varying harmonics in real-time. Following a brief summary of the currently used off-line harmonics

Lok-Fu Pak; Venkata Dinavahi; Gary Chang; Michael Steurer; Paulo F. Ribeiro

2007-01-01

337

Root Cause Analysis to Identify Physical Causes G. Medina Olivaa  

E-print Network

and Effects Analysis (FMEA), Fault Tree Analysis (FTA), Pareto Analysis, Bayesian Inference and Ishikawa Analysis, Fault Tree Analysis (Gano, 2007) and (Rossing et al., 2010). While qualitative methods is based on the integration of several RCA tools such as fault tree, FMECA and HAZOP. The objective

Boyer, Edmond

338

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

E-print Network

Modeling and Analysis of Safety-Critical Cyber Physical Systems using State/Event Fault Trees Introduction For ensuring the safety of technical systems, fault trees (FTs) are an estab- lished methodology in safety analysis. Especially in the eld of cyber physical systems (CPSs), where numerous interfaces come

Paris-Sud XI, Université de

339

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

340

Physics  

NASA Astrophysics Data System (ADS)

Nuclear, plasma, elementary particle, and atomic and molecular physics are surveyed along with the physics of condensed matter and relativistic astrophysics. Attention is given to the discovery of quarks, psi particles, bosons and nuclear quantum states, the role of group theory and the search for a unified field theory. Also considered are magnetic and inertial confinement regarding fusion power, and the use of tunable lasers and microwave spectroscopy to study Rydberg states. In addition, surface physics, amorphous solids, superfluidity and gravitational collapse are discussed.

Bromley, D. A.

1980-07-01

341

Luke J. Harmon Curriculum Vitae  

E-print Network

University, St. Louis, MO Ph. D. in Evolution, Ecology, and Population Biology Advisor: Dr. Jonathan Losos in action examined over a phylogeny" (co-PI Joe Felsenstein; total $132,794, Harmon lab budget $65,306) 2009

Harmon, Luke

342

Simulation and Analysis of Physical Processes for Aiding Technology Development  

E-print Network

of Physics 1999 Presentations at several conferences, including NASA and international workshop at Harvard Funding from CIPA Metrology SPIE 2003, 1999 Applied Phys. Lett. 2002 IEEE Trans. Semi. Manufacturing

Cole, Dan C.

343

Helical harmonics for static fields.  

PubMed

Helical harmonic solutions of Laplace's equation are derived using a right-handed nonorthogonal helical coordinate system and a modified separation of variables technique. Unlike the Cartesian or cylindrical coordinate systems, in the helical system, two different sets of solutions are admitted, one right handed and one left handed. Consequently, the helical harmonics are used to solve the boundary value problem of two nested helices with different radii set to different potential values. PMID:11580458

Overfelt, P L

2001-09-01

344

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

345

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,

346

Topological correction of brain surface meshes using spherical harmonics.  

PubMed

A brain surface reconstruction allows advanced analysis of structural and functional brain data that is not possible using volumetric data alone. However, the generation of a brain surface mesh from MRI data often introduces topological defects and artifacts that must be corrected. We show that it is possible to accurately correct these errors using spherical harmonics. Our results clearly demonstrate that brain surface meshes reconstructed using spherical harmonics are free from topological defects and large artifacts that were present in the uncorrected brain surface. Visual inspection reveals that the corrected surfaces are of very high quality. The spherical harmonic surfaces are also quantitatively validated by comparing the surfaces to an "ideal" brain based on a manually corrected average of twelve scans of the same subject. In conclusion, the spherical harmonics approach is a direct, computationally fast method to correct topological errors. PMID:20426104

Yotter, Rachel Aine; Dahnke, Robert; Gaser, Christian

2009-01-01

347

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

348

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

349

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

350

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

351

Relation of squeezed states between damped harmonic and simple harmonic oscillators  

NASA Technical Reports Server (NTRS)

The minimum uncertainty and other relations are evaluated in the framework of the coherent states of the damped harmonic oscillator. It is shown that the coherent states of the damped harmonic oscillator are the squeezed coherent states of the simple harmonic oscillator. The unitary operator is also constructed, and this connects coherent states with damped harmonic and simple harmonic oscillators.

Um, Chung-In; Yeon, Kyu-Hwang; George, Thomas F.; Pandey, Lakshmi N.

1993-01-01

352

Ejs Adiabatically Changing Harmonic Oscillator Model  

NSDL National Science Digital Library

The Ejs Adiabatically Changing Harmonic Oscillator model displays the frictionless dynamics of a mass on a spring where the angular frequency of the oscillator adiabatically changes with time according to: ω = ωâ + α tβ. The simulation displays the cumulative and current phase space motion as well as the area in phase space. All parameters can be changed via textboxes. 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 Adiabatically Changing Harmonic Oscillator 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_analytical_mechanics_adiabatic.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 Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-07-10

353

Ejs Damped Driven Simple Harmonic Oscillator Model  

NSDL National Science Digital Library

The Ejs Damped Driven Simple Harmonic Oscillator model displays the dynamics of a ball attached to an ideal spring with a damping force and a sinusoidal driving force. The spring is initially unstretched and the ball has zero initial velocity. The initial position of the ball can be changed by click-dragging the ball when the simulation is paused. 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 Damped Driven Simple Harmonic Oscillator 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_osc_SHODriven.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 Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-05

354

Inharmonicity Analysis: A Novel Physical Method for Acoustic Screening of Dysphonia  

NASA Astrophysics Data System (ADS)

In the United States 6.8% of men, women, and children report current voice problems and approximately 29% will report some problems during their lifetime. Often this dysphonia is due to pathologies of the vocal folds. The authors (a physicist and a speech pathologist) describe an interdisciplinary approach that shows promise of detecting physiological abnormalities of the vocal folds from an analysis of the Fourier spectrum of spoken ``tokens.'' The underlying principle maintains that the normal human vocal fold is a linear oscillator that emits overtones that are very nearly precise integral values of the fundamental. Physiological problems of the vocal folds, however, introduce mechanical non-linearities that manifest themselves as frequency deviations from the ideal harmonic (that is, integral) values. The authors quantify this inharmonicity, describing and illustrating how one can obtain and analyze such data. They outline, as well, a proposed program to assess the clinical sensitivity and significance of the analysis discussed in this work.

Matteson, Sam; Lu, Fang-Ling

2008-10-01

355

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

356

Physical disability among physicians: an analysis of 259 cases.  

PubMed

This article presents data on 259 physicians and medical students with a wide range of physical disabilities and specialty training. Three out of four were in active medical practice despite their disability, most often in the specialties of internal medicine, family practice, or psychiatry. Neurological disorders accounted for over half the sample, with spinal cord injury, multiple sclerosis, stroke, and post-polio weakness being the most commonly encountered diagnoses. These data indicate that physically disabled physicians are more numerous than the previous literature would suggest that they are capable of practising in many professional specialties. PMID:2962980

Wainapel, S F

1987-01-01

357

Boston University Physics Applets: Dissecting the SHM Equation  

NSDL National Science Digital Library

This web page is an interactive physics animation relating to simple harmonic oscillation. Two spring oscillators are displayed with a choice of three views: different amplitudes, different frequencies, or different phases. The user can observe changes in the graphs as a function of each. Included is an analysis of the SHM general equation based upon the graphs displayed. This item is part of a collection of similar simulation-based activities for students of introductory physics.

Duffy, Andrew

2008-08-22

358

Global Analysis of Urban Population Distributions and the Physical Environment  

Microsoft Academic Search

Urbanization represents a significant recent change in the human habitat. The physical environment of modern urban areas is very different from the environments in which humans evolved and from those of the modern rural settlements that serve as population catchment areas for growing cities. In this sense, migration from rural to urban areas is a form of rapid environmental change

Christopher Small

359

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

360

Physical characteristics and general compositions analysis of Avocados in Taiwan  

Microsoft Academic Search

The aim of this study was to investigate the physical characteristics and general compositions of several varieties of Avocados produce in Taiwan both in fresh and ripened states. Samples of avocados collected from several production areas of Taiwan were analyzed for fruits weight, percentage of skin, edible pulp and seed, values of color difference, hardness, and general composition, including moisture,

Kuo-Shu Tseng; Yaw-Kun Tseng

361

Analysis of physical data from the Chernobyl unit 4 accident  

Microsoft Academic Search

Physical data about the Chernobyl accident has been collected inside the Shelter, near the destroyed unit, and from fallout. This paper summarizes accident analyses conducted in 1986 (a short time after the April 26, 1986 accident), analyses conducted in 1995 and 1996 with the Ukrainian Academy of Sciences, analyses by Russia's MinAtom in 1996, and results of continuing analyses. “TECHOCENTRE”

Edward E. Purvis; Vladimir V. Tokarevsky; Y. V. Veryuzsky

1997-01-01

362

Cyclotron harmonics in opacities of isolated neutron star atmospheres  

E-print Network

Some of X-ray dim isolated neutron stars (XDINS) and central compact objects in supernova remnants (CCO) show absorption features in their thermal soft X-ray spectra. There have been suggestions in the literature that these features could be due to the periodic peaks in free-free absorption opacities, caused either by Landau quantization of electron motion in magnetic fields B10^{13} G. I review the physics behind cyclotron quantum harmonics in free-free photoabsorption, discuss different approximations for their calculation, and explain why the ion cyclotron harmonics (beyond the fundamental) cannot be observed.

Potekhin, A Y

2010-01-01

363

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

364

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-

365

Implications of postseismic gravity change following the great 2004 Sumatra-Andaman earthquake from the regional harmonic analysis of GRACE intersatellite tracking data  

USGS Publications Warehouse

We report Gravity Recovery and Climate Experiment (GRACE) satellite observations of coseismic displacements and postseismic transients from the great Sumatra-Andaman Islands (thrust event; Mw ???9.2) earthquake in December 2004. Instead of using global spherical harmonic solutions of monthly gravity fields, we estimated the gravity changes directly using intersatellite range-rate data with regionally concentrated spherical Slepian basis functions every 15-day interval. We found significant step-like (coseismic) and exponential-like (postseismic) behavior in the time series of estimated coefficients (from May 2003 to April 2007) for the spherical Slepian function's. After deriving coseismic slip estimates from seismic and geodetic data that spanned different time intervals, we estimated and evaluated postseismic relaxation mechanisms with alternate asthenosphere viscosity models. The large spatial coverage and uniform accuracy of our GRACE solution enabled us to clearly delineate a postseismic transient signal in the first 2 years of postearthquake GRACE data. Our preferred interpretation of the long-wavelength components of the postseismic avity change is biviscous viscoelastic flow. We estimated a transient viscosity of 5 ??17 Pa s and a steady state viscosity of 5 ?? 1018 - 1019 Pa s. Additional years of the GRACE observations should provide improved steady state viscosity estimates. In contrast to our interpretation of coseismic gravity change, the prominent postearthquake positive gravity change around the Nicobar Islands is accounted for by seafloor uplift with less postseismic perturbation in intrinsic density in the region surrounding the earthquake. Copyright 2008 by the American Geophysical Union.

Han, S.-C.; Sauber, J.; Luthcke, S.B.; Ji, C.; Pollitz., F. F.

2008-01-01

366

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

367

Digital Filter Design with Harmonics Estimation for Power Supplies  

NASA Astrophysics Data System (ADS)

The quality of voltage waveforms is nowadays an issue of the utmost importance for power utilities and electronic equipment. Modern frequency power converters generate a wide spectrum of harmonic components, which deteriorate the quality of the delivered energy, increase the energy losses as well as decrease their liability of a power supplies. In large converters systems not only harmonics, but also considerable interharmonics strongly deteriorate the quality of the power supply voltage. The estimation of the components parameters is very important for control and protection tasks. Digital low pass filter overcome the voltage drift, temperature drift and time drift problems and can be used for harmonic detection for better utilization in real-time. Real-time detection of harmonics can be implemented using MATLAB software and developing simulation circuit set up. With the appropriate cutoff frequency f c and nth order of filter, low pass filter and band-pass filter for real-time harmonic detection can be analyzed. In this paper the aim is to design filters using different methods including Prony analysis. The monitoring of power system harmonics an important issue in the frame of modern power system management and control can be achieved easily using digital filters.

Shah, P. J.; Saxena, R.; Chawla, M. P. S.

2012-06-01

368

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

369

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

370

Analysis of self-directed mastery learning of honors physics  

NASA Astrophysics Data System (ADS)

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 with feedback, a choice of learning activities, and multiple forms of support. This study was conducted within two sections of honors physics at a private high school (N=24). Students' learning activity choices, time investments, and perceptions (assessed through a post survey) were tracked and analyzed. SDL readiness was linked to success in mastering physics concepts. The three research questions pursued in this study were: What SDL activities did honors physics students choose in their self-directed mastery learning environment? How many students achieved concept mastery and how did they spend their time? Did successful and unsuccessful students perceive the self-directed mastery learning environment differently? Only seven of 24 students were successful in passing the similar concept-based unit tests within four tries, and these seven students were separated into a "successful" group and the other 17 into an "unsuccessful" group. Differences between the two groups were analyzed. A profile of a self-directed secondary honors physics student emerged. A successful self-directed student invested more time learning from activities rather than simply completing them, focused on learning concepts more than rote operations, intentionally selected activities to fill in gaps of knowledge and practice concepts, actively constructed knowledge into a cognitive framework, engaged in academic discourse with instructor and peers as they made repeated attempts to master content and pass the test given constructive feedback, used a wide variety of learning resources, and managed their workload to meet deadlines. This capstone study found that parallel instruction in content and SDL skills could be important for improving learning outcomes and better equipping secondary honors physics students for college and life in general. Mastery learning principles coupled with modeling in self-direction appear mutually reinforcing and, when more explicitly approached, should yield dual benefits in concept mastery as well as self-efficacy.

Athens, Wendy

371

The Physics of Music.  

ERIC Educational Resources Information Center

Suggests using musical instruments to demonstrate physics concepts. Topics include: pitch and frequency; string vibrations; string-resonator system; wind instruments; harmonic content; transients; scales and temperament; psycho-acoustical affects; and electronic music. (SK)

Hoon, S. R.; Tanner, B. K.

1981-01-01

372

Coupled-cavity VCSELs: numerical analysis of physical phenomena  

NASA Astrophysics Data System (ADS)

A self-consistent model of a GaAs-based 850 nm coupled-cavity vertical-cavity surface-emitting diode laser is presented. The analyzed laser consists of two identical AlGaAs cavities with GaAs quantum wells, separated with 10 pairs of middle DBR. The current apertures are realized by ion-implantation for the top cavity and selective oxidation for the bottom. To accurately simulate the physical phenomena present in the CW regime of the analyzed device, we use a multi-physical model, which comprises self-consistent Finite Element Method (FEM) thermo-electrical model. The numerical parameters have been found by the calibration based on experimental results. We have analyzed and shown the influence of the driving voltages on the temperature distribution within the analyzed structure and current densities in both cavities.

Frasunkiewicz, Leszek; Dems, Maciej; Sarza?a, Robert P.; Choquette, Kent D.; Panajotov, Krassimir; Czyszanowski, Tomasz

2014-05-01

373

Analysis of Percussion Grip for Physically Based Character Animation  

E-print Network

. Firstly, it provides realistic exam- ples of the human motion under study for driving the virtual This paper presents the analysis of percussion tech- nique for the simulation of virtual timpani playing sit the dynamic control of virtual characters and the analysis of percussion instrumental gestures

Paris-Sud XI, Université de

374

Physically-based Models For Flood Frequency Analysis  

NASA Astrophysics Data System (ADS)

Flood frequency models can be broadly classified into: (1) empirical, (2) phenomeno- logical, and (3) physically based. Despite their appeal, physically-based models have yet to become models of choice in hydrologic practice. Along the lines of physically based models and recognizing that channels are the dominant conduits for transmis- sion of flood waters, it is plausible to develop a model that employs the physics of channel flow routing and in which no explicit consideration is given to the hydrologic processes occurring on the land areas of the watershed. It is well accepted that the complete linearized Saint Venant equation and its simplifications provide a reason- able representation of the physics of channel flow. It is then hypothesized that impulse response function (IRF) of such models can be considered as a probability density function (PDF) for FFA. The impulse response of a linear convective-diffusion anal- ogy (LD) model is proposed for perennial rivers and that of a linear kinematic dif- fusion (KD) model for ephemeral streams. Each of them has two parameters which are derived using the method of moments (MOM) and maximum likelihood method (MLM). Also derived are errors in quantiles for both methods. Both distributions show an equivalency of MOM and MLM with respect to the mean U an important property in the case of unknown true distribution function. The LD model was tested using 39 series of Polish rivers showing its superiority over Log-normal - the main competitor among the family of two-parameter PDFs for the analyzed data. In particular, the LD model represents FF-characteristics well when the LD is likely to be the best of all lin- ear flood routing models. The KD distribution was tested on 44 annual peak flows data series containing zero values. A comparison of empirical and KD distributions shows that MOM better reproduces the upper tail of the distribution, while MLM is more ro- bust for higher sample values and more conditioned on the value of the probability of the zero value event. A comparison of the fit of the KD and the Muskingum-like prob- ability distribution to the data, which is the only plausible alternative within the family of two-parameter distributions for discontinuous samples with zero values, shows the superiority of the KD model over the Muskingum-like model. In conclusion, the im- pulse responses of both flood routing models are promising models for FFA.

Strupczewski, W. G.; Singh, V. P.; Weglarczyk, S.

375

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

376

Rock physics analysis for time-lapse seismic at Schiehallion Field, North Sea  

Microsoft Academic Search

Rock physics analysis plays a vital role in time-lapse seismic interpretation because it provides the link between changes in rock and fluid properties and the resulting seismic data response. In this case study of the Schiehallion Field, we discuss a number of issues that commonly arise in rock physics analyses for time-lapse studies. We show that: 1 Logarithmic fits of

Mark Meadows; Don Adams; Rich Wright; Ali Tura; Steve Cole; David Lumley

2005-01-01

377

A Functional Analysis of Moderate-to-Vigorous Physical Activity in Young Children  

ERIC Educational Resources Information Center

Inadequate physical activity increases the risks related to a number of health problems in children, most notably obesity and the corresponding range of associated health problems. The purpose of the current study was to conduct a functional analysis to investigate the effects of several consequent variables on moderate-to-vigorous physical…

Larson, Tracy A.; Normand, Matthew P.; Morley, Allison J.; Miller, Bryon G.

2013-01-01

378

Volume 18, number 4 CHEMICAL PHYSICS LETTERS 15February 1973 ANALYSIS OF POLYATOMIC $PECTRA  

E-print Network

Volume 18, number 4 CHEMICAL PHYSICS LETTERS 15February 1973 ANALYSIS OF POLYATOMIC $PECTRA USING. technical assistance. 46.5 #12;Volume 18. number 4 CHEMiCAL PHYSICS LETTERS 15 February 1973 ETALON BEAM TUNABLE LASER-INDUCED FLUORESCENCE: APPLICATIONS TO THE NO, VISIBLE BAND SYSTEM" C.G. STEVENS, h1.W

Zare, Richard N.

379

Leisure-time physical activity and lung cancer: a meta-analysis  

Microsoft Academic Search

Objective: Several studies have evaluated the relationship between physical activity and lung cancer. To summarize and review these studies, we conducted a meta-analysis of all relevant reports published from 1966 through October 2003.

Adonina Tardon; Won Jin Lee; Miguel Delgado-Rodriguez; Mustafa Dosemeci; Demetrius Albanes; Robert Hoover; Aaron Blair

2005-01-01

380

Methods for Examining Small Literatures: Explication, Physical Analysis, and Citation Patterns.  

ERIC Educational Resources Information Center

Analyzes literature on information overload research in library studies using explication, physical analysis, and citation patterns. Makes cross-discipline comparisons with consumer science and psychology/psychiatry. Contains 93 references. (PEN)

Akin, Lynn

1998-01-01

381

Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF).  

National Technical Information Service (NTIS)

The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF)...

M. Sharirli, J. L. Rand, M. K. Sasser, F. R. Gallegos

1992-01-01

382

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

Roy, Subrata

383

Simple Harmonic Oscillator JS Model  

NSDL National Science Digital Library

The Simple Harmonic Oscillator JS Model displays the dynamics of a ball attached to an ideal spring. The spring is initially stretched and the ball has zero initial velocity. The initial position of the ball can be changed by click-dragging the ball when the simulation is paused. The Simple Harmonic Oscillator JS Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support. This model runs on tablets.

Christian, Wolfgang; Franciscouembre

2014-01-01

384

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

385

A new harmonic analyzer  

E-print Network

accuracy, and which is quick, sinple snd snail in physical sine, to fulfill the ns?d of research and industry. PART I. ? GENERAL INTRODUCTION Usually it i. s convenient to resolve a complex wave into a Fourier series expansion such as: A (I) f...(x) = ? +AI Cos x + A2 Cos 2x + A3 Cos 3x +. . . + A Cos nx +. . . 1 2 3 ' ' n + Bl Sin x t B2 Sin 2x & B3 Sin 3x +. . . + Bn Sin nx +. . . or A (2) f(x) ~ ? + ( A Cos nx + Bn Sin nx ) where: A 1 n 2)I f(x) Cos nx dx (4) B 1 fl f(x) Sin nx dx 2 l1...

Tchamran-Savehi, Abbas

2012-06-07

386

A scientometrics and social network analysis of Malaysian research in physics  

NASA Astrophysics Data System (ADS)

This conference proceeding presents an empirical assessment on the domestic publication output and structure of scientific collaboration of Malaysian authors for the field of physics. Journal articles with Malaysian addresses for the subject area "Physics" and other sub-discipline of physics were retrieved from the Thomson Reuters Web of Knowledge database spanning the years 1980 to 2011. A scientometrics and social network analysis of the Malaysian physics field was conducted to examine the publication growth and distribution of domestic collaborative publications; the giant component analysis; and the degree, closeness, and betweenness centralisation scores for the domestic co-authorship networks. Using these methods, we are able to gain insights on the evolution of collaboration and scientometric dimensions of Malaysian research in physics over time.

Tan, H. X.; Ujum, E. A.; Ratnavelu, K.

2014-03-01

387

SPECIAL ISSUE DEVOTED TO THE 25th ANNIVERSARY OF THE A.M. PROKHOROV GENERAL PHYSICS INSTITUTE: Generation of laser-pulse-field harmonics in a gas upon impact ionisation of atoms  

NASA Astrophysics Data System (ADS)

The generation of harmonics of a high-power-laser-pulse field in a gas during impact ionisation of atoms by oscillating electrons is studied theoretically. Fields are considered under conditions when the oscillation energy of electrons in the radiation field, remaining nonrelativistic, considerably exceeds the ionisation potential of an atom. In addition, the radiation field was assumed weak compared to the atomic field (Ea = 5.1×109 V cm-1), which allowed us to neglect the field ionisation of atoms, taking into account only the impact ionisation of atoms by oscillating electrons. Under such conditions, along with the elastic scattering of electrons, the inelastic scattering of oscillating electrons accompanied by ionisation of gas atoms can make a significant contribution to a nonlinear current induced in the plasma.

Kuzelev, M. V.; Rukhadze, A. A.

2007-10-01

388

Cost and performance analysis of physical protection systems -- A case study  

SciTech Connect

Design and analysis of physical protection systems requires (1) identification of mission critical assets; (2) identification of potential threats that might undermine mission capability; (3) identification of the consequences of loss of mission-critical assets (e.g., time and cost to recover required capability and impact on operational readiness); and (4) analysis of the effectiveness of physical protection elements. CPA -- Cost and Performance Analysis -- addresses the fourth of these four issues. CPA is a methodology that joins Activity Based Cost estimation with performance-based analysis of physical protection systems. CPA offers system managers an approach that supports both tactical decision making and strategic planning. Current exploratory applications of the CPA methodology address analysis of alternative conceptual designs. Hypothetical data is used to illustrate this process.

Hicks, M.J.; Snell, M.S.; Sandoval, J.S.; Potter, C.S.

1998-08-01

389

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

390

Foliated stochastic calculus: Harmonic measures  

Microsoft Academic Search

In this article we present an intrinsec construction of foliated Brownian motion via stochastic calculus adapted to foliation. The stochastic approach together with a proposed foliated vector calculus provide a natural method to work on harmonic measures. Other results include a decomposition of the Laplacian in terms of the foliated and basic Laplacians, a characterization of totally invariant measures and

Pedro J. Catuogno; Diego S. Ledesma; Paulo R. Ruffino

2010-01-01

391

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

2001-01-01

392

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

393

Properties of a harmonic lattice  

Microsoft Academic Search

Elastic and thermal properties of crystals depend upon anharmonic behaviour of the atomic bonds that hold them together. In extrapolating these properties to pressures of the Earth's deep interior, an idealized reference material, a harmonic crystal, is often referred to. However, the discussions are often clouded by misunderstanding of what the properties of such a crystal would be. It is

Frank Stacey

1993-01-01

394

Harmonization of company taxation systems  

Microsoft Academic Search

The author of the following article gives a survey of the different corporation tax systems and rates in the individual EC-member\\u000a countries, explains the need for a harmonization of direct company taxation within the Community, and discusses the Commission’s\\u000a recent proposal as compared with other possible approaches.

Heinrich Hölzler

1976-01-01

395

Lasing on the third harmonic  

SciTech Connect

The Los Alamos Free-Electron Laser has recently lased near 4 {mu}m on the third harmonic of the fundamental frequency of about 12 {mu}m. By choice of intercavity apertures and cavity length, lasing can be forced to occur on both frequencies simultaneously or on either one alone. 8 refs., 3 figs., 1 tab.

Warren, R.W.; Haynes, L.C.; Feldman, D.W.; Stein, W.E.; Gitomer, S.J.

1989-01-01

396

A statistical physics analysis of expenditure in the UK  

E-print Network

Most papers which explored so far macroeconomic variables took into account income and wealth. Equally important as the previous macroeconomic variables is the expenditure or consumption, which shows the amount of goods and services that a person or a household purchased. Using statistical distributions from Physics, such as Fermi-Dirac and polynomial distributions, we try to fit the data regarding the expenditure distribution divided in deciles of population according to their income (gross and disposable expenditure are taken into account). Using coefficient of determination as theoretical tool in order to assess the degree of success for these distributions, we find that both distributions are really robust in describing the expenditure distribution, regardless the data set or the methodology used to calculate the expenditure values for the deciles of income. This is the first paper to our knowledge which tackles expenditure, especially using a method to describe expenditure such as lower limit on expendit...

Oltean, Elvis

2014-01-01

397

Experimental analysis of nonlinear oscillations in the undergraduate physics laboratory  

NASA Astrophysics Data System (ADS)

In this paper, we present a simple experiment to introduce the nonlinear behaviour of oscillating systems in the undergraduate physics laboratory. The transverse oscillations of a spring allow reproduction of three totally different scenarios: linear oscillations, nonlinear oscillations reducible to linear for small displacements, and intrinsically nonlinear oscillations. The chosen approach consists of measuring the displacements using video photogrammetry and computing the velocities and the accelerations by means of a numerical differentiation algorithm. In this way, one can directly check the differential equation of the motion without having to integrate it, or perform an experimental study of the potential energy in each of the analysed scenarios. This experiment allows first year students to reflect on the consequences and the limits of the linearity assumption for small displacements that is so often made in technical studies.

Moreno, R.; Page, A.; Riera, J.; Hueso, J. L.

2014-01-01

398

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

399

Physical Violence between Siblings: A Theoretical and Empirical Analysis  

ERIC Educational Resources Information Center

This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have…

Hoffman, Kristi L.; Kiecolt, K. Jill; Edwards, John N.

2005-01-01

400

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

Microsoft Academic Search

Tools are necessary for the DoD 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, we are developing new methods to combine these three

B. Van Leeuwen; D. Burton; U. Onunkwo; M. McDonald

2009-01-01

401

Physical Violence Between Siblings A Theoretical and Empirical Analysis  

Microsoft Academic Search

This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have significantly higher levels of sibling violence than the other three types

Kristi L. Hoffman; K. Jill Kiecolt; John N. Edwards

2005-01-01

402

Physics-Based Simulator for NEO Exploration Analysis & Modeling  

E-print Network

Laboratory (JPL) to explore potential surface and near-surface mission op- erations at Near Earth Objects (NEOs). The simulator is under development at JPL and can be used to provide detailed analysis the DSENDS spacecraft modeling tool available at JPL that has been previously used on such missions

403

Harmonic ratcheting for fast acceleration  

NASA Astrophysics Data System (ADS)

A major challenge in the design of rf cavities for the acceleration of medium-energy charged ions is the need to rapidly sweep the radio frequency over a large range. From low-power medical synchrotrons to high-power accelerator driven subcritical reactor systems, and from fixed focus alternating gradient accelerators to rapid cycling synchrotrons, there is a strong need for more efficient, and faster, acceleration of protons and light ions in the semirelativistic range of hundreds of MeV/u. A conventional way to achieve a large, rapid frequency sweep (perhaps over a range of a factor of 6) is to use custom-designed ferrite-loaded cavities. Ferrite rings enable the precise tuning of the resonant frequency of a cavity, through the control of the incremental permeability that is possible by introducing a pseudoconstant azimuthal magnetic field. However, rapid changes over large permeability ranges incur anomalous behavior such as the "Q-loss" and "f-dot" loss phenomena that limit performance while requiring high bias currents. Notwithstanding the incomplete understanding of these phenomena, they can be ameliorated by introducing a "harmonic ratcheting" acceleration scheme in which two or more rf cavities take turns accelerating the beam—one turns on when the other turns off, at different harmonics—so that the radio frequency can be constrained to remain in a smaller range. Harmonic ratcheting also has straightforward performance advantages, depending on the particular parameter set at hand. In some typical cases it is possible to halve the length of the cavities, or to double the effective gap voltage, or to double the repetition rate. This paper discusses and quantifies the advantages of harmonic ratcheting in general. Simulation results for the particular case of a rapid cycling medical synchrotron ratcheting from harmonic number 9 to 2 show that stability and performance criteria are met even when realistic engineering details are taken into consideration.

Cook, N.; Brennan, J. M.; Peggs, S.

2014-04-01

404

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

405

Universal Bose-Fermi mass-relations in Kaluza-Klein supergravity and harmonic analysis on coset manifolds with Killing spinors  

Microsoft Academic Search

Universal mass-relations between Bose and Fermi modes are obtained via general relations existing among the spectra of invariant operators on coset manifolds with Killing spinors. In particular zero-modes for pseudoscalars, spinors, and Lichnerowitz scalars are always related to the isometry and cohomology properties of the manifold. The structure of the four-dimensional supersymmetry rules on physical modes is given. Furthermore, the

R. D'Auria; P. Fre

1985-01-01

406

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

407

The LivePhoto Physics videos and video analysis site  

NASA Astrophysics Data System (ADS)

The LivePhoto site is similar to an archive of short films for video analysis. Some videos have Flash tools for analyzing the video embedded in the movie. Most of the videos address mechanics topics with titles like Rolling Pencil (check this one out for pedagogy and content knowledge—nicely done!), Juggler, Yo-yo, Puck and Bar (this one is an inelastic collision with rotation), but there are a few titles in other areas (E&M, waves, thermo, etc.).

Abbott, David

2009-09-01

408

Toward a Cost/Benefit Analysis of Physical Fitness  

PubMed Central

This article, which is based, in part, on a paper presented to the Canadian Association of Sport Sciences, Quebec City, in November 1985, evaluates the principles of cost/benefit and cost-effectiveness analysis in the specific context of fitness programming. Because of difficulties in valuing all aspects of fitness and health—particularly survival after retirement—cost-effectiveness analysis is generally preferred. Allowance must be made for inflation, the discount rate (except in a “steady state” analysis), marginal costs of program expansion, opportunity costs incurred by participants, the changing fabric of society, the economic multiplication of investment in fitness, and anticipated participation rates. Benefits may be observed by the individual (improved health), the corporation (reduced turnover and absenteeism, increased productivity, fewer injuries), and the state (reduced direct and indirect costs of illness, improved lifestyle, reduced demand for geriatric services). Program costs vary widely with the activity that is undertaken, but even daily walking involves the participant in some expense. Employee programs often cost $500-$750 per participant/year, while, depending on the sport and local speculation by land “developers”, community programs may cost $175-$1,000 per participant/year. Cost/effectiveness analyses allow governments to reach informed decisions, but they cannot always answer associated ethical problems such as determining the value of human life, and the rights of the individual as opposed to those of society. PMID:21267294

Shephard, Roy J.

1986-01-01

409

Indefinite harmonic forms and gauge theory  

NASA Astrophysics Data System (ADS)

Indecomposable representations have been extensively used in the construction of conformal and de Sitter gauge theories. It is thus noteworthy that certain unitary highest weight representations have been given a geometric realization as the unitary quotient of an indecomposable representation using indefinite harmonic forms [RSW]. We apply this construction to SU (2,2) and the de Sitter group. The relation is established between these representations and the massless, positive energy representations of SU (2,2) obtained in the physics literature. We investigate the extent to which this construction allows twistors to be viewed as a gauge theory of SU (2,2). For the de Sitter group, on which the gauge theory of singletons is based, we find that this construction is not directly applicable.

Nakashima, M.

1988-03-01

410

High-order harmonic generation in the presence of a resonance  

SciTech Connect

We investigate high-order harmonic generation from laser-irradiated systems that support a shape resonance. From the numerical solution of the time-dependent Schroedinger equation, we calculate the harmonic spectra and the time-frequency analysis of the harmonic intensity and phase. The analysis reveals the separate contributions of the short and long trajectories as well as the resonance. A range of harmonics is strongly enhanced by the presence of the resonance irrespective of the pulse length. The signature of the resonance remains significant after coherent summation over intensities as a simple method to simulate macroscopic effects. The time-frequency analysis supports the recently proposed four-step mechanism of the enhanced harmonic generation process.

Tudorovskaya, Maria [Institut fuer Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover, Appelstrasse 2, D-30167 Hannover (Germany); Institut fuer Physik, Universitaet Kassel, Heinrich-Plett-Strasse 40, D-31432 Kassel (Germany); Lein, Manfred [Institut fuer Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover, Appelstrasse 2, D-30167 Hannover (Germany)

2011-07-15

411

Optimal control subsumes harmonic control Amine Boumaza  

E-print Network

Optimal control subsumes harmonic control Amine Boumaza LORIA Campus Scientifique B.P. 239 54506 planning within the frame- works of optimal control and harmonic control. We present a formal evidence, in the continuous domain and in a stan- dard discretization, that harmonic control is the limit case of some optimal

Paris-Sud XI, Université de

412

Optimal control subsumes harmonic control Amine Boumaza  

E-print Network

Optimal control subsumes harmonic control Amine Boumaza LORIA Campus Scientifique B.P. 239 54506 planning within the frame- works of optimal control and harmonic control. We present a formal evidence, in continuous domain and in a standard discretization, that harmonic control is the limit case of a some optimal

Paris-Sud XI, Université de

413

Modeling a Harmonic Drive Gear Transmission  

Microsoft Academic Search

In order to capture the dynamic behavior of harmonic drives, dynamic models must include accurate representations of transmission friction, compliance, and kinematic error. Experimental observations are used to guide the development of a model to describe harmonic-drive operation. This model is able to replicate many of the features observed in actual harmonic-drive dynamic response. Valuable insights are gained about the

Timothy D. Tuttle; Warren P. Seering

1993-01-01

414

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

415

A Cepstrum-Based Technique for Determining a Harmonics-to-Noise Ratio in Speech Signals.  

ERIC Educational Resources Information Center

A new method to calculate a spectral harmonics-to-noise (HNR) ratio is presented. The method discriminates between harmonic and noise energy in the magnitude spectrum by means of a comb-filtering operation in the cepstrum domain. HNR is seen to be a useful parameter in the analysis of voice quality. (Author/DB)

de Krom, Guus

1993-01-01

416

Manipulability Analysis of Kicking Motion in Soccer Based on Human Physical Properties  

Microsoft Academic Search

This paper presents an analysis tool of kicking motion in soccer based on robotic techniques. The developed tool can calculate kinematics, dynamics, and manipulability of trainee's movements with considerations of human physical characteristics from the trainee's postures measured by a motion capture system, and can visually provide the quantitative analysis to users in the main window of the tool. The

Yoshiyuki Tanaka; Mitsuhisa Shiokawa; Hiroyuki Yamashita; T. Tsuji

2006-01-01

417

Analysis of the New Physics Textbook for the 9th Grade of the Greek Schools  

Microsoft Academic Search

In the following paper we analyze the new textbook of Physics for the 9th grade (last year of compulsory education) of Greek schools. For this analysis, we use the framework that was developed by Koulaidis, B., Dimopoulos, K., Sklaveniti S., Xristidou B. (2002) The emphasis of this analysis is not in the content of the book, but in the transformation

Georgios Kountouriotis

2010-01-01

418

Harmonic pinnacles in the Discrete Gaussian model  

E-print Network

The 2D Discrete Gaussian model gives each height function $\\eta : \\mathbb{Z}^2\\to\\mathbb{Z}$ a probability proportional to $\\exp(-\\beta \\mathcal{H}(\\eta))$, where $\\beta$ is the inverse-temperature and $\\mathcal{H}(\\eta) = \\sum_{x\\sim y}(\\eta_x-\\eta_y)^2$ sums over nearest-neighbor bonds. We consider the model at large fixed $\\beta$, where it is flat unlike its continuous analog (the Gaussian Free Field). We first establish that the maximum height in an $L\\times L$ box with 0 boundary conditions concentrates on two integers $M,M+1$ with $M\\sim \\sqrt{(1/2\\pi\\beta)\\log L\\log\\log L}$. The key is a large deviation estimate for the height at the origin in $\\mathbb{Z}^2$, dominated by "harmonic pinnacles", integer approximations of a harmonic variational problem. Second, in this model conditioned on $\\eta\\geq 0$ (a floor), the average height rises, and in fact the height of almost all sites concentrates on levels $H,H+1$ where $H\\sim M/\\sqrt{2}$. This in particular pins down the asymptotics, and corrects the order, in results of Bricmont, El-Mellouki and Fr\\"ohlich (1986), where it was argued that the maximum and the height of the surface above a floor are both of order $\\sqrt{\\log L}$. Finally, our methods extend to other classical surface models (e.g., restricted SOS), featuring connections to $p$-harmonic analysis and alternating sign matrices.

Eyal Lubetzky; Fabio Martinelli; Allan Sly

2014-05-20

419

Complex metabolic oscillations in plants forced by harmonic irradiance.  

PubMed Central

Plants exposed to harmonically modulated irradiance, approximately 1 + cos(omegat), exhibit a complex periodic pattern of chlorophyll fluorescence emission that can be deconvoluted into a steady-state component, a component that is modulated with the frequency of the irradiance (omega), and into at least two upper harmonic components (2omega and 3omega). A model is proposed that accounts for the upper harmonics in fluorescence emission by nonlinear negative feedback regulation of photosynthesis. In contrast to simpler linear models, the model predicts that the steady-state fluorescence component will depend on the frequency of light modulation, and that amplitudes of all fluorescence components will exhibit resonance peak(s) when the irradiance frequency is tuned to an internal frequency of a regulatory component. The experiments confirmed that the upper harmonic components appear and exhibit distinct resonant peaks. The frequency of autonomous oscillations observed earlier upon an abrupt increase in CO(2) concentration corresponds to the sharpest of the resonant peaks of the forced oscillations. We propose that the underlying principles are general for a wide spectrum of negative-feedback regulatory mechanisms. The analysis by forced harmonic oscillations will enable us to examine internal dynamics of regulatory processes that have not been accessible to noninvasive fluorescence monitoring to date. PMID:12324435

Nedbal, Ladislav; Brezina, Vitezslav

2002-01-01

420

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

421

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

422

Second and Third Harmonic Measurements at the Linac Coherent Light Source  

SciTech Connect

The Linac Coherent Light Source (LCLS) started user commissioning in October of 2009, producing Free Electron Laser (FEL) radiation between 800 eV and 8 keV [1]. The fundamental wavelength of the FEL dominates radiation in the beamlines, but the beam also produces nonnegligible levels of radiation at higher harmonics. The harmonics may be desirable as a source of harder X-rays, but may also contribute backgrounds to user experiments. In this paper we present preliminary measurements of the second and third harmonic content in the FEL. We also measure the photon energy cutoff of the soft X-ray mirrors to determine the extent to which higher harmonics reach the experimental stations. We present preliminary second and third harmonic measurements for LCLS. At low energies (below 1 keV fundamental) we measure less than 0.1% second harmonic content. The second harmonic will be present in the soft X-ray beam line for fundamental photon energies below approximately 1.1 keV. At low and high energies, we measure third harmonic content ranging from 0.5% to 3%, which is consistent with expectations. For both second and third harmonics, experimental work is ongoing. More rigorous analysis of the data will be completed soon.

Ratner, D.; /Stanford U., Phys. Dept.; Brachmann, A.; Decker, F.J.; Ding, Y.; Dowell, D.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Huang, Z.; Hering, P.; Iverson, R.; Krzywinski, J.; Loos, H.; Messerschmidt, M.; Nuhn, H.D.; Smith, T.; Turner, J.; Welch, J.; White, W.; Wu, J.; /SLAC

2011-01-03

423

Axisymmetric generalized harmonic evolution code  

SciTech Connect

We describe the first axisymmetric numerical code based on the generalized harmonic formulation of the Einstein equations, which is regular at the axis. We test the code by investigating gravitational collapse of distributions of complex scalar field in a Kaluza-Klein spacetime. One of the key issues of the harmonic formulation is the choice of the gauge source functions, and we conclude that a damped-wave gauge is remarkably robust in this case. Our preliminary study indicates that evolution of regular initial data leads to formation both of black holes with spherical and cylindrical horizon topologies. Intriguingly, we find evidence that near threshold for black hole formation the number of outcomes proliferates. Specifically, the collapsing matter splits into individual pulses, two of which travel in the opposite directions along the compact dimension and one which is ejected radially from the axis. Depending on the initial conditions, a curvature singularity develops inside the pulses.

Sorkin, Evgeny [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Muehlenberg 1, D-14476, Golm (Germany)

2010-04-15

424

Third harmonic generation in graphene  

NASA Astrophysics Data System (ADS)

We report the measurement of optical third harmonic generation from single-layer graphene and few-layer graphite flakes produced by exfoliation. In the measurements, femtosecond near-infrared laser pulses were used to irradiate the samples. The emission observed scales with the cube of the intensity of the incident near-infrared pulse and with one third of the incident wavelength - both are clear evidences of third harmonic generation. We deduced an effective third-order susceptibility for single layer graphene to be on the order of 10-16 m^2/V^2. By measuring a set of flakes with different numbers of atomic layers, we found that for a few layers, the emission scales with the square of the number of atomic layers.

Kumar, Nardeep; Kumar, Jatinder; Gerstenkorn, Chris; Wang, Rui; Chiu, Hsin-Ying; Smirl, Arthur; Zhao, Hui

2013-03-01

425

PREFACE: 14th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2011)  

NASA Astrophysics Data System (ADS)

ACAT2011 This volume of Journal of Physics: Conference Series is dedicated to scientific contributions presented at the 14th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2011) which took place on 5-7 September 2011 at Brunel University, UK. The workshop series, which began in 1990 in Lyon, France, brings together computer science researchers and practitioners, and researchers from particle physics and related fields in order to explore and confront the boundaries of computing and of automatic data analysis and theoretical calculation techniques. It is a forum for the exchange of ideas among the fields, exploring and promoting cutting-edge computing, data analysis and theoretical calculation techniques in fundamental physics research. This year's edition of the workshop brought together over 100 participants from all over the world. 14 invited speakers presented key topics on computing ecosystems, cloud computing, multivariate data analysis, symbolic and automatic theoretical calculations as well as computing and data analysis challenges in astrophysics, bioinformatics and musicology. Over 80 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. Panel and round table discussions on data management and multivariate data analysis uncovered new ideas and collaboration opportunities in the respective areas. This edition of ACAT was generously sponsored by the Science and Technology Facility Council (STFC), the Institute for Particle Physics Phenomenology (IPPP) at Durham University, Brookhaven National Laboratory in the USA and Dell. We would like to thank all the participants of the workshop for the high level of their scientific contributions and for the enthusiastic participation in all its activities which were, ultimately, the key factors in the success of the workshop. Further information on ACAT 2011 can be found at http://acat2011.cern.ch Dr Liliana Teodorescu Brunel University ACATgroup The PDF also contains details of the workshop's committees and sponsors.

Teodorescu, Liliana; Britton, David; Glover, Nigel; Heinrich, Gudrun; Lauret, Jérôme; Naumann, Axel; Speer, Thomas; Teixeira-Dias, Pedro

2012-06-01

426

Student trajectories in physics: the need for analysis through a socio-cultural lens  

Microsoft Academic Search

An analysis of student connections through time and space relative to the core discipline of physics is attempted, as viewed\\u000a through the lens of actor-network-theory, by Antonia Candela. Using lenses of cultural realities, networks, and perceived\\u000a power in the discourse of one specific university in the capital city of Mexico and one undergraduate physics classroom, the\\u000a trajectories and itineraries of

Mara Zapata

2010-01-01

427

Foliated stochastic calculus: Harmonic measures  

Microsoft Academic Search

In this article we present an intrinsec construction of foliated Brownian\\u000amotion via stochastic calculus adapted to foliation. The stochastic approach\\u000atogether with a proposed foliated vector calculus provide a natural method to\\u000awork on harmonic measures. Other results include a decomposition of the\\u000aLaplacian in terms of the foliated and basic Laplacians, a characterization of\\u000atotally invariant measures and

Pedro J. Catuogno; Diego S. Ledesma; Paulo R. Ruffino

2010-01-01

428

Cost and performance analysis of conceptual designs of physical protection systems  

SciTech Connect

CPA -- Cost and Performance Analysis -- is a methodology that joins Activity Based Cost (ABC) estimation with performance based analysis of physical protection systems. CPA offers system managers an approach that supports both tactical decision making and strategic planning. Current exploratory applications of the CPA methodology are addressing analysis of alternative conceptual designs. To support these activities, the original architecture for CPA, is being expanded to incorporate results from a suite of performance and consequence analysis tools such as JTS (Joint Tactical Simulation), ERAD (Explosive Release Atmospheric Dispersion) and blast effect models. The process flow for applying CPA to the development and analysis conceptual designs is illustrated graphically.

Hicks, M.J.; Snell, M.S.; Sandoval, J.S.; Potter, C.S.

1998-06-01

429

Intramolecular Dynamics Probed using High Harmonic Generation  

NASA Astrophysics Data System (ADS)

We observed intramolecular dynamics as a modulation in high harmonic emission. We excite coherent vibrations in CF3Cl using impulsive Raman scattering with a short laser pulse. A second laser pulse generates high harmonics. The harmonic yield is observed to oscillate at frequencies corresponding to three vibrational modes of CF3Cl. In a second experiment, we used UV light to excite and dissociate CF3I, and follow the dynamic evolution by monitoring the harmonic yield. We observe a large modulation of the harmonic yield, likely due to resonance excitation and subsequent dissociation of the molecule. We speculate that the less-than full baseline recovery after the UV pulse is due to ionization, and that the harmonic yield is sensitive to the bond length during dissociation. By these two experiments, we confirm that high harmonic generation is a sensitive probe of intramolecular dynamics and may yield more information simultaneously than conventional ultrafast spectroscopic techniques.

Hooper, Robynne; Zhou, Xibin; Li, Wen; Wagner, Nick; Kapteyn, Henry; Murnane, Margaret

2007-06-01

430

Studying the 3 alpha reaction in hyperspherical harmonic approach  

NASA Astrophysics Data System (ADS)

In this work, the 3 alpha reaction is studied by using the Faddeev hyper-spherical harmonic (HH) method [1]. Starting from a three body model, we derive the analytical formulas for the quadrupole strength function B(E2) as well as the reaction rate which is well known for the two particles but not for three particle system. The 2+ state and the 0+ resonance are well reproduced but we consider the contributions of the nonresonant continuum states to the reaction rate in a consistent manner. Considering only Coulomb interaction for the three alpha scattering problem we can obtain analytical continuum wave functions for the 0+ states. At low temperature our calculations agree very well with NACRE and there is an expected increase in the reaction rate at high temperature due to the nuclear contribution (resonant process). A full calculation with the R-matrix method in hyper-spherical coordinate space is being done to include nuclear and coulomb in equal footing. Final results and a detail physical analysis of the reaction mechanism will be presented and compared with [2,3]. [1] I. J. Thompson, F. M. Nunes, B. V. Danilin, Comput.Phys.Comm. 161, 87-107 (2004). [2] K.Ogata, M.Kan, M.Kamimura, Prog. Theor. Phys. 122, 1055 (2009). [3] R. de Diego, E. Garrido, D.V. Fedorov, A.S. Jensen, EPL. 90, 52001(2010).

Nguyen, Ngoc

2011-10-01

431

Limitations and improvements for harmonic generation measurements  

NASA Astrophysics Data System (ADS)

A typical acoustic harmonic generation measurement comes with certain limitations. Firstly, the use of the plane wave-based analysis used to extract the nonlinear parameter, ?, ignores the effects of diffraction, attenuation and receiver averaging which are common to most experiments, and may therefore limit the accuracy of a measurement. Secondly, the method usually requires data obtained from a through-transmission type setup, which may not be practical in a field measurement scenario where access to the component is limited. Thirdly, the technique lacks a means of pinpointing areas of damage in a component, as the measured nonlinearity represents an average over the length of signal propagation. Here we describe a three-dimensional model of harmonic generation in a sound beam, which is intended to provide a more realistic representation of a typical experiment. The presence of a reflecting boundary is then incorporated into the model to assess the feasibility of performing single-sided measurements. Experimental validation is provided where possible. Finally, a focusing acoustic source is modelled to provide a theoretical indication of the afforded advantages when the nonlinearity is localized.

Best, Steven; Croxford, Anthony; Neild, Simon

2014-02-01

432

Third-harmonic generation for photoionization studies  

SciTech Connect

Our group at Oak Ridge National Laboratory (ORNL) has studied resonantly enhanced multiphoton ionization (MPI) of alkali atoms, rare gases, and small molecules using tightly focused dye laser beams (power densities of 10/sup 9/ to 10/sup 11/ W/cm/sup 2/). In the case of alkali atoms, some ionization signals appear as a result of gas density effects (dimers or quasi-collisions) as previously discovered by Collins and his collaborators. These have been termed hybrid-resonances. By contrast, in the case of the rare gases, certain resonance ionization signals disappear with increasing gas density. The disappearance of the ionization signals in the rare gases is due to the interference of excitation of the third-harmonic and fundamental laser beam. At low pressure (10/sup -7/ to 10/sup -5/ torr) we have studied (1) mass spectra, (2) kinetic energy released in ionic fragmentation, and (3) photoelectron kinetic energy spectra using time-of-flight mass analysis and a 160/sup 0/ spherical sector electrostatic energy analyzer. These experiments, combined with two-color dye laser experiments, can often offer an unambiguous and detailed description of the MPI and subsequent fragmentation events. The major part of this talk will be devoted to the production and the use of vacuum ultraviolet (VUV) light from third-harmonic generation (THG) in the rare gases.

Compton, R.N.; Miller, J.C.

1982-01-01

433

Harmonics based detection of magnetic nanoparticle dynamics for multiparameter biosensing  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles have an increasing role in the clinical and pharmaceutical realms where their physical properties can be exploited for imaging, biological and functional sensing, control of cellular processes, therapeutics, and an array of other applications. When excited by an alternating magnetic field, these particles will produce a series of harmonics. These harmonics have been exploited for in vitro particle detection and for in vivo imaging using magnetic particle imaging (MPI). Using a new technique, which we have termed magnetic spectroscopy of nanoparticle Brownian motion (MSB), we have shown how information about the physical environment of the particles can be extracted from this harmonic spectrum. A variety of physical effects have been detected and/or quantified including temperature, viscosity, nanoparticle binding, and aggregation. Further, we found these different environments to have a unique impact on the spectral signature of the nanoparticles which allows for simultaneous quantification of multiple environmental states. The thesis culminates with a study of MSB as a means for monitoring the cellular uptake of nanoparticles. Potential applications for MSB as a standalone technology and the potential for incorporation into MPI are discussed throughout.

Rauwerdink, Adam M.

434

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

435

Wavelet analysis and accelerator signals  

SciTech Connect

Wavelets have suddenly become very popular in signal analysis applications. They have become a darling topic in several fields: astronomy, image processing, filtering, theoretical physics, and harmonic analysis, to name only a few. This paper focuses on applications for wavelet analysis in accelerator engineering, specifically, signal processing. It is split into three parts; the first contrasts wavelet analysis with Fourier analysis, the second constructs a simple wavelet basis as a tutorial, the third demonstrates the analytic uses of wavelets with the help of a software analyzing tool. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Stillman, A. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

1995-05-05

436

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

437

Comparative analysis of female physicists in the physical sciences: Motivation and background variables  

NASA Astrophysics Data System (ADS)

The majority of existing science, technology, engineering, and mathematics (STEM) research studies compare women to men, yet a paucity of research exists that examines what differentiates female career choice within the physical sciences. In light of these research trends and recommendations, this study examines the following question: On average, do females who select physics as compared to chemistry doctoral programs differ in their reported personal motivations and background factors prior to entering the field? This question is analyzed using variables from the Project Crossover Survey data set through a subset of female physical science doctoral students and scientists (n =1137). A logistic regression analysis and prototypical odds ratio uncover what differentiates women in the physical sciences based on their academic achievement and experiences ranging from high school through undergraduate education. Results indicate that females who have negative undergraduate chemistry experiences as well as higher grades and positive experiences in undergraduate physics are more likely to pursue a career in physics as opposed to chemistry. Conclusions suggest that a greater emphasis should be placed on the classroom experiences that are provided to females in gateway physics courses. Analyses show that women are not a single entity that should only be examined as a whole group or in comparison to men. Instead women can be compared to one another to see what influences their differences in educational experiences and career choice in STEM-based fields as well as other academic areas of study.

Dabney, Katherine P.; Tai, Robert H.

2014-06-01

438

WAVEMOTH-FAST SPHERICAL HARMONIC TRANSFORMS BY BUTTERFLY MATRIX COMPRESSION  

SciTech Connect

We present Wavemoth, an experimental open source code for computing scalar spherical harmonic transforms (SHTs). Such transforms are ubiquitous in astronomical data analysis. Our code performs substantially better than existing publicly available codes owing to improvements on two fronts. First, the computational core is made more efficient by using small amounts of pre-computed data, as well as paying attention to CPU instruction pipelining and cache usage. Second, Wavemoth makes use of a fast and numerically stable algorithm based on compressing a set of linear operators in a pre-computation step. The resulting SHT scales as O(L{sup 2}log{sup 2} L) for the resolution range of practical interest, where L denotes the spherical harmonic truncation degree. For low- and medium-range resolutions, Wavemoth tends to be twice as fast as libpsht, which is the current state-of-the-art implementation for the HEALPix grid. At the resolution of the Planck experiment, L {approx} 4000, Wavemoth is between three and six times faster than libpsht, depending on the computer architecture and the required precision. Because of the experimental nature of the project, only spherical harmonic synthesis is currently supported, although adding support for spherical harmonic analysis should be trivial.

Seljebotn, D. S., E-mail: d.s.seljebotn@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)

2012-03-01

439

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

440

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

441

Comparing Child Outcomes of Physical Punishment and Alternative Disciplinary Tactics: A Meta-Analysis  

Microsoft Academic Search

This meta-analysis investigates differences between the effect sizes of physical punishment and alternative disciplinary tactics for child outcomes in 26 qualifying studies. Analyzing differences in effect sizes reduces systematic biases and emphasizes direct comparisons between the disciplinary tactics that parents have to select among. The results indicated that effect sizes significantly favored conditional spanking over 10 of 13 alternative disciplinary

Robert E. Larzelere; Brett R. Kuhn

2005-01-01

442

A content analysis of print media coverage of gender, women and physical activity  

Microsoft Academic Search

This paper presents the results of an investigation of print media coverage of gender and physical activity. The analysis was based on an examination of two samples: all issues of four Canadian daily newspapers for a 6-m-onth period and all issues of Chatelaine, a monthly Canadian women's magazine, for a period of 10 years and 6 months. Results indicate the

Nancy Theberge

1991-01-01

443

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

444

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

445

Data analysis and graphing in an introductory physics laboratory: spreadsheet versus statistics suite  

NASA Astrophysics Data System (ADS)

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.

Peterlin, Primož

2010-07-01

446

Are worksite interventions effective in increasing physical activity? A systematic review and meta-analysis  

Microsoft Academic Search

Worksite interventions have the potential to reach a broad and captive audience and overcome one of the most widely cited barriers to increasing physical activity (PA), namely, a lack of time. A systematic review and random effects, meta-analysis assessed the effectiveness of worksite interventions to enhance PA. Thirty-seven intervention evaluations reporting 55 unique interventions met our inclusion criteria. Results indicate

Charles Abraham; Ella Graham-Rowe

2009-01-01

447

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

448

Logical analysis of maintenance and performance data of physical assets, ID34  

Microsoft Academic Search

We present a novel approach to fault detection and Physical Asset Health Management (PAHM) called Logical Analysis of Data (LAD). LAD is a supervised learning, artificial intelligence, data mining technique that possesses distinctive advantages which proved to be of use in PAHM. This approach has been introduced by a group of researchers at Rutgers University in the USA, in the

Soumaya Yacout

2012-01-01

449

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

450

Analysis and Synthesis of Facial Image Sequences Using Physical and Anatomical Models  

Microsoft Academic Search

We present a new approach to the analysis ofdynamic facial images for the purposes of estimating and resynthesizingdynamic facial expressions. The approach exploits asophisticated generatire model of the human face originallydeveloped for realistic facial animation. The face model, whichmay be simulated and rendered at interactive rates on a graphicsworkstation, incorporates a physics-based synthetic facial tissueand a set of anatomically motivated

Demetri Terzopoulos; Keith Waters

1993-01-01

451

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 SIGN REACTION CONSTANTS IN DSP RELATIONS. Rainer Glaser,*a Stephanie Nelson,a Michael Lewis-organic chemistry and the electronic structure theory of reaction kinetics: Why is R/F = usually positive and close

Glaser, Rainer

452

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

Microsoft Academic Search

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

Sims

1985-01-01

453

A Demonstration of the Analysis of Variance Using Physical Movement and Space  

ERIC Educational Resources Information Center

Classroom demonstrations help students better understand challenging concepts. This article introduces an activity that demonstrates the basic concepts involved in analysis of variance (ANOVA). Students who physically participated in the activity had a better understanding of ANOVA concepts (i.e., higher scores on an exam question answered 2…

Owen, William J.; Siakaluk, Paul D.

2011-01-01

454

Systems Analysis of Plant Functional, Transcriptional, Physical Interaction, and Metabolic Networks  

E-print Network

REVIEW Systems Analysis of Plant Functional, Transcriptional, Physical Interaction, and Metabolic Division of Plant and Crop Sciences, School of Biosciences and Centre for Plant Integrative Biology-throughput biochemical, genetic, and molecular approaches to generate omics data that can be analyzed and used

455

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

456

Silhouette-based human pose analysis for feedback during physical exercises  

Microsoft Academic Search

In this paper I propose a computer vision-based method for analyzing the human pose during physical exercises performed for a virtual trainer. Body part labeling and difference analysis between a measurement and reference silhouette are combined into a result consisting of a set of vectors per body part, indicating the errors made. The approach depends heavily on a statistical model

Frank Zijlstra

457

Theory and optical implementation of the geometrical approach of multiple circular harmonic filters  

NASA Astrophysics Data System (ADS)

The circular harmonic filter contains only one component of the image. Its discrimination capability has been questionable. The geometrical approach of multiple circular harmonic filters uses relative locations of the correlation peaks as the rotation-, shift-, and intensity-invariant features for pattern recognition. Each feature depends on the entire image. This approach has a good discrimination capability. Optical real-time implementation of the on-axis continuous phase-only circular harmonic filters by the use of a commercial liquid-crystal television is shown. A harmonic analysis shows that the phase-mostly filter can tolerate coupled amplitude modulation at the acceptable expense of the output signal-to-noise ratio. An optical experiment of the geometrical approach of multiple circular harmonic filters for a multiple-image input is described. The cross-correlation peaks between the individual filters and the clutter are eliminated, because they are not in good locations.

Shen, Lixin; Sheng, Yunlong; Prémont, Guy

1995-07-01

458

Spatiotemporal representation of the pitch of harmonic complex tones in auditory nerve  

E-print Network

The pitch of harmonic complex tones plays an important role in speech and music perception and the analysis of auditory scenes, yet traditional rate–place and temporal models for pitch processing provide only an incomplete ...

Cedolin, Leonardo

459

Data Acquisition in a High Harmonic Generation Lab and at LCLS.  

National Technical Information Service (NTIS)

In this paper, we examine data acquisition in a high harmonic generation (HHG) lab and preliminary data analysis with the Cyclohexadiene Collaboration at the Linac Coherent Lightsource (LCLS) at SLAC National Accelerator Laboratory. HHG experiments have a...

T. Hirokawa

2011-01-01

460

Teaching from a Microgravity Environment: Harmonic Oscillator and Pendulum  

NASA Astrophysics Data System (ADS)

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 the period should be independent of gravity. However, the equation for the period of a pendulum does include the acceleration due to gravity, so the period of a pendulum should appear longer under reduced gravity (such as lunar or Martian gravity) and shorter under hyper-gravity. These environments can be simulated aboard an aircraft. Video of the experiments being performed aboard the aircraft is to be used in introductory physics classes. Students will be able to record information from watching the experiment performed aboard the aircraft in a similar manner to how they collect data in the laboratory. They can then determine if the experiment matches theory. Video and an experimental procedure are being prepared based upon this flight, and these materials will be available for download by faculty anywhere with access to the internet who wish to use the experiment in their own classrooms.

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

2009-04-01

461

Replication of a path analysis model of secondary physics enrollments: 20 years later  

NSDL National Science Digital Library

The percentage of enrollment in physics (PEP) at the secondary level in the United States has been approximately 20% for the past few decades. In an attempt to isolate variables related to physics enrollment. Bryant (1977) conducted a path analysis model of secondary physics enrollment in New York State. This present study is a replication and extension of the study conducted by Bryant. Current data were used to verify the Bryant model and construct models with data available since Bryant's work. Data gathered by the New York State Education Department for the 1990-1991 school year were used. The source of this data included surveys completed by teachers and administrators on student characteristics and school facilities. A data analysis similar to Bryant's was conducted to determine whether the relationships between a set of predictor variables and physics enrollment had changed in the past 20 years. The findings indicate that there has been no change in the set of variables related to physics enrollment.

Sobolewski, Stanley; Doran, Rodney

2005-11-23

462

Scientometric analysis of physics (1979-2008): A quantitative description of scientific impact  

NASA Astrophysics Data System (ADS)

Citations are a way to show how researchers build on existing research to further evolve research. The citation count is an indication of the influence of specific articles. The importance of citations means that it is valuable to analyze the articles that are cited the most. This research investigates highly-cited articles in physics (1979-2008) using citation data from the ISI Web of Science. In this study, 1544205 articles were examined. The objective of the analysis was to identify and list the highly-productive countries, institutions, authors, and fields in physics. Based on the analysis, it was found that the USA is the world leader in physics, and Japan has maintained the highest growth rate in physics research since 1990. Furthermore, the research focus at Bell Labs and IBM has played important roles in physics. A striking fact is that the five most active authors are all Japanese, but the five most active institutions are all in the USA. In fact, only The University of Tokyo is ranked among the top 11 institutions, and only American authors have single-author articles ranked among the top 19 articles. The highest-impact articles are distributed across 25 subjects categories. Physics, Multidisciplinary has 424 articles, and is ranked at No. 1 in total articles; followed by Physics, Condensed Matter. The study can provide science policy makers with a picture of innovation capability in this field and help them make better decisions. Hopefully, this study will stimulate useful discussion among scientists and research managers about future research directions.

Zheng, YanNing; Yuan, JunPeng; Pan, YunTao; Zhao, XiaoYuan

2011-01-01

463

Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)  

SciTech Connect

The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief review of the studies involved in Phases I and II of the program.

Sharirli, M.; Rand, J.L.; Sasser, M.K.; Gallegos, F.R.

1992-01-01

464

Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)  

SciTech Connect

The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief review of the studies involved in Phases I and II of the program.

Sharirli, M.; Rand, J.L.; Sasser, M.K.; Gallegos, F.R.

1992-12-01

465

Resource Plasticity: Detailing a Common Chain of Reasoning with Damped Harmonic Motion  

NSDL National Science Digital Library

As part of ongoing research into cognitive processes and student thought, we have investigated the interplay between mathematics and physics resources in intermediate mechanics students. We present evidence from a reformed sophomore-level mechanics class which contains both tutorial and lecture components. In the context of writing Newton's Second Law for damped harmonic motion, students discuss the signs of the spring and damping forces. Using a grounded theory approach, we identify a common chain of reasoning in which a request for reasoning is followed by elaborative sense-making and checks for consistency, finishing with an optional appeal for group consensus. Our analysis provides evidence for a description of student thinking in terms of Plasticity, an extension of Resource Theory.

Sayre, Eleanor C.; Wittmann, Michael C.; Donovan, John E.

2007-11-19

466

Phase-merging enhanced harmonic generation free-electron laser  

NASA Astrophysics Data System (ADS)

Together with one of its variants, the recently proposed phase-merging enhanced harmonic generation (PEHG) free-electron laser (FEL) is systematically studied in this paper. Different from a standard high-gain harmonic generation scheme, a transverse gradient undulator is employed to introduce a phase-merging effect into the transversely dispersed electron beam in PEHG. The analytical theory of the phase-merging effect and the physical mechanism behind the phenomenon are presented. Using a representative set of beam parameters, intensive start-to-end simulations for soft x-ray FEL generation are given to illustrate the performance of PEHG. Moreover, some practical issues that may affect the performance of PEHG are also discussed.

Feng, Chao; Deng, Haixiao; Wang, Dong; Zhao, Zhentang

2014-04-01

467

Third-harmonic generation in isotropic media by focused pulses  

SciTech Connect

For focused pulses of light in isotropic nonlinear media, third-harmonic generation can be strongly affected by group-velocity mismatch between the fundamental and third-harmonic. There is a characteristic time determined by the group-velocity mismatch and the Rayleigh range of the focused pulse. The dynamics depend on two dimensionless quantities, namely the ratio of the characteristic time to the pulse duration and the phase-velocity mismatch times the Rayleigh range. Pulses shorter than the characteristic time have physics described by simple analytic formulas. Pulses near the characteristic time have an intermediate behavior given by an explicit but more complicated formula. Pulses longer than the characteristic time tend to the continuous-wave case.

Tasgal, Richard S.; Band, Y.B. [Departments of Chemistry and Electro-Optics, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

2004-11-01

468

Higher harmonics generation in relativistic electron beam with virtual cathode  

NASA Astrophysics Data System (ADS)

The study of the microwave generation regimes with intense higher harmonics taking place in a high-power vircator consisting of a relativistic electron beam with a virtual cathode has been made. The characteristics of these regimes, in particular, the typical spectra and their variations with the change of the system parameters (beam current, the induction of external magnetic field) as well as physical processes occurring in the system have been analyzed by means of 3D electromagnetic simulation. It has been shown that the system under study demonstrates the tendency to the sufficient growth of the amplitudes of higher harmonics in the spectrum of current oscillations in the VC region with the increase of beam current. The obtained results allow us to consider virtual cathode oscillators as promising high power mmw-to-THz sources.