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1

Guelph Physics Tutorials: Simple Harmonic Motion  

NSDL National Science Digital Library

This website offers a tutorial on harmonic motion. The tutorial includes an introduction to the properties that describe harmonic motion, the connection between simple harmonic and uniform circular motions, and provides students with self-paced questions to test their understanding. This is part of series of tutorials on physics and mathematics to be used in physics classes.

2004-12-19

2

Harmonic Analysis of Stream Temperatures.  

National Technical Information Service (NTIS)

Computer program B260 is one of a series of programs in the SYSLAB system for data analysis of water-quality records. This special-purpose program was developed for harmonic analysis of water-quality constituent records, primarily stream-temperature data....

T. D. Steele

1974-01-01

3

Data Compression and Harmonic Analysis  

Microsoft Academic Search

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

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

1998-01-01

4

LUNAR GRAVITY: A HARMONIC ANALYSIS  

Microsoft Academic Search

A sixteenth-degree and sixteenth- ing a selenopotential usable for global geophysi- order spherical harmonic lunar gravity field has cal analysis, errors still exist in the locations been derived from the long-term KeplerJan varia- of some prominent nearside anomalies. Errors of tions in the orbits of the Apollo subsatellites this type cause considerable problems when the and Lunar Orbiter 5. This

Alfred J. Ferrari

1977-01-01

5

Representation Discovery in Planning using Harmonic Analysis  

Microsoft Academic Search

This paper summarizes ongoing research on a frame- work for representation learning using harmonic analy- sis, a subeld of mathematics. Harmonic analysis in- cludes Fourier analysis, where new eigenvector rep- resentations are constructed by diagonalization of op- erators, and wavelet analysis, where new representa- tions are constructed by dilation. The approach is pre- sented specically in the context of Markov

Jeff Johns; Sarah Osentoski; Sridhar Mahadevan

6

Reconstruction of local neutron physical functionals in surface harmonics method  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

7

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

8

Load harmonics analysis and mitigation  

Microsoft Academic Search

Load harmonics in electrical submersible pump (ESP) systems could interact with the inductance of the transformers and shunt capacitance of the downhole cable creating a severe resonance condition. Although load filters are developed by some drive manufacturers as standard products or even integrated as part of the drive, such filters might not work well for ESP systems. In this paper,

Xiaodong Liang; Rotimi Adedun

2012-01-01

9

Venus topography - A harmonic analysis  

Microsoft Academic Search

A model of Venusian global topography has been obtained by fitting an eighteenth-degree harmonic series to Pioneer Venus orbiter radar altimeter data. The mean radius is (6051.45 + or - 0.04) km. The corresponding mean density is (5244.8 + or 0.5) kg\\/cu m. The center of figure is displaced from the center of mass by (0.339 + or - 0.088)

B. G. Bills; Michael Kobrick

1985-01-01

10

Lunar gravity - A harmonic analysis  

Microsoft Academic Search

A sixteenth-degree and sixteenth-order spherical harmonic lunar gravity field has been derived from the long-term Keplerian variations in the orbits of the Apollo subsatellites and Lunar Orbiter 5. This model resolves the major mascon gravity anomalies of the lunar near side and is in very good agreement with line-of-sight acceleration results. The far-side map shows the major ringed basins to

A. J. Ferrari

1977-01-01

11

Automating Functional Harmonic Analysis: The Funchal System  

Microsoft Academic Search

Functional harmonic analysis is an important task in music composition, accompaniment, arrangement and others. However, the solutions are still not satisfactory. The proposed process is divided into two levels: the former extends one of previous works in the domain to carry out a richer analysis of chord grids and is where the very analysis is performed, and the latter is

Ricardo Scholz; Vítor Dantas; Geber Ramalho

2005-01-01

12

Modular Approach to Physics: Simple Harmonic Motion - Weighted Spring  

NSDL National Science Digital Library

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

13

Harmonic analysis of electrical distribution systems  

SciTech Connect

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

NONE

1996-03-01

14

The Orthosymplectic Lie Supergroup in Harmonic Analysis  

NASA Astrophysics Data System (ADS)

The study of harmonic analysis in superspace led to the Howe dual pair (O(m)×Sp(2n),sl2). This Howe dual pair is incomplete, which has several implications. These problems can be solved by introducing the orthosymplectic Lie supergroup OSp(m|2n). We introduce Lie supergroups in the supermanifold setting and show that everything is captured in the Harish-Chandra pair. We show the uniqueness of the supersphere integration as an orthosymplectically invariant linear functional. Finally we study the osp(m|2n)-representations of supersymmetric tensors for the natural module for osp(m|2n).

Coulembier, Kevin

2010-09-01

15

Harmonic analysis of Fermilab main ring quadrupoles  

SciTech Connect

The Main Ring Quadrupoles have been used in the Fermilab Main Ring and will be utilized in the proposed Fermilab Main Injector. Utilizing a rotating coil harmonic measurement system, a sample of more than 35 Fermilab Main Ring Quadrupoles have been measured. The asymmetric design of these magnets provides many easily measured harmonic coefficients. Results for harmonic coefficients at various excitation levels are presented. 5 refs., 3 figs., 1 tab.

Brown, B.C.; Mazur, P.O.; Ostiguy, J.F.; Pruss, S.M.; Turkot, F.

1991-05-01

16

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

17

General analysis of harmonic transfer through converters  

Microsoft Academic Search

Harmonic transfer from DC-side to AC-side and vice-versa through a three-phase bridge power converter is treated by using space vectors. The dependency of the relative frequency of a harmonic and its sequence (positive\\/negative) is illustrated. It is shown that the derived relationships are valid for both voltage-source and current-source power converters. Thereby, the relationships for the frequency transformation through power

Ying Jiang; A. Ekstrom

1997-01-01

18

Platonic polyhedra tune the 3-sphere: harmonic analysis on simplices  

NASA Astrophysics Data System (ADS)

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

Kramer, Peter

2009-04-01

19

Spatial analysis of harmonic oscillation of gypsy moth outbreak ...  

Treesearch

Title: Spatial analysis of harmonic oscillation of gypsy moth outbreak intensity ... geographic heterogeneity in strength of periodicity and the frequency of outbreaks. ... We suggest that this pattern emerges because high host-tree availability ...

20

Noncanonical harmonic and anharmonic oscillator in high-energy physics  

SciTech Connect

We study the eigenvalues of the noncanonical harmonic and anharmonic oscillator, by using different values of the elementary length l corresponding to typical cross sections for the strong interactions. There is evidence for a correlation between the energies of elementary particles (mesons, baryons, resonances) and the energy eigenvalues of the noncanonical theory.

Jannussis, A.; Vavougios, D.

1986-09-01

21

Physically Meaningful Harmonization of Tire\\/Pavement Friction Measurement Devices  

Microsoft Academic Search

Accurate characterization and evaluation of tire\\/pavement friction is critical in assuring runway and highway safety. Historically, Pavement Friction Measurement Devices (PFMDs) employing different measuring mechanisms have been used to evaluate tire\\/pavement friction. They yield significantly disparate friction coefficients under the same contact conditions. Currently, an empirically developed data harmonization method based on a reference device (Dynamic Friction Tester (DFT)) is

Madhura Priyanga Nishshanke Rajapakshe

2011-01-01

22

Local harmonic analysis of planetary Doppler gravity data  

Microsoft Academic Search

Planetary gravity fields represented in terms of spherical harmonics or surface mass distributions\\\\ do not have the necessary resolution to permit gravity analysis of local features. Doppler gravity maps representing residual line-of-sight (LOS) accelerations have much greater resolution but cannot be used for conventional geophysical analysis due to the geometric distortions inherent in LOS gravity patterns and lack of normalization

A. W. Gerhard Kunze

1985-01-01

23

Local harmonic analysis of planetary Doppler gravity data  

Microsoft Academic Search

Planetary gravity fields represented in terms of spherical harmonics or surface mass distributions do not have the necessary resolution to permit gravity analysis of local features. Doppler gravity maps representing residual line-of-sight (LOS) accelerations have much greater resolution but cannot be used for conventional geophysical analysis due to the geometric distortions inherent in LOS gravity patterns and lack of normalization

A. W. G. Kunze

1985-01-01

24

Segmented chirp Z-transform and multiple deep dip windows for electrical power system harmonic analysis  

Microsoft Academic Search

The combined use of the Segmented Chirp Z-Transform (SCZT) and of the Multiple Deep Dip (MDD) windows is proposed and applied to electrical power system harmonic analysis. The goal of increasing the resolvability of low magnitude non-harmonic tones close in frequency to higher magnitude harmonics and the detectability of very low magnitude high frequency harmonics is pursued. The SCZT allows

P. Daponte; D. Menniti; A. Testa

1996-01-01

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

A Spherical Harmonic Analysis of the Earth's Topography  

Microsoft Academic Search

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

Georges Balmino; Kurt Lambeck; William M. Kaula

1973-01-01

27

Harmonic analysis on local fields and adelic spaces. I  

NASA Astrophysics Data System (ADS)

We develop harmonic analysis on the objects of a category C_2 of infinite-dimensional filtered vector spaces over a finite field. This category includes two-dimensional local fields and adelic spaces of algebraic surfaces defined over a finite field. As the main result, we construct the theory of the Fourier transform on these objects and obtain two-dimensional Poisson formulae.

Osipov, D. V.; Parshin, A. N.

2008-10-01

28

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

29

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

30

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

Microsoft Academic Search

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

W. H. Chow; D. P. Steenson

2003-01-01

31

Harmonic Analysis of Polynomial Threshold Functions  

Microsoft Academic Search

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

Jehoshua Bruck

1990-01-01

32

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

33

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

2012-01-04

34

Multiscale image features analysis with circular harmonic wavelets  

NASA Astrophysics Data System (ADS)

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

Jacovitti, Giovanni; Neri, Alessandro

1995-09-01

35

A modified Ibrahim time domain algorithm for operational modal analysis including harmonic excitation  

Microsoft Academic Search

Operational modal analysis procedures are efficient techniques to identify modal properties of structures excited through unknown random noise produced during operation. In many practical cases, harmonic excitations are often present in addition to the white-noise and, if the harmonic frequency is close to structural frequencies, standard identification techniques fail. Here, a method is presented to take into account the harmonic

P. Mohanty; D. J. Rixen

2004-01-01

36

Out of control because of harmonics-an analysis of the harmonic response of an inverter locomotive  

Microsoft Academic Search

Presents a method to use linear analysis to capture the frequency coupling of nonlinear and time-varying components. System stability is analyzed by connecting the harmonic transfer functions of the different component models. This facilitates an object-oriented approach to modeling, which supports reuse of models. An analysis of the complete railway system is, of course, difficult. Several locomotives can be moving

E. Mollerstedt; B. Bernhardsson

2000-01-01

37

Analysis of MHD harmonic modes from the novel tangential X-ray diagnostic in EAST tokamak  

NASA Astrophysics Data System (ADS)

The magnetohydrodynamics (MHD) harmonic modes as well as the underlying physics have been investigated in detail by applications of the Hilbert-Huang transform (HHT), higher-order spectrum (HOS) analysis and Fourier transform (FT), based on the novel tangential X-ray (TX) diagnostic (Li E. et al., Rev. Sci. Instrum., 81 (2010) 106102). Those signal process methods were applied to a rotating m/n=2/1 magnetic island, and it was found that its second-order harmonic m/n=4/2 appearing in FT spectrum (m, n are poloidal and toroidal mode numbers, respectively) was not an intrinsic mode, but a measure of distortion of the saturated magnetic island m/n=2/1.

Li, Erzhong; Hu, Liqun

2011-04-01

38

Analytic scaling analysis of high harmonic generation conversion efficiency.  

PubMed

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 simulations, and enable a detailed scaling analysis of HHG efficiency as a function of drive laser parameters and material properties. Moreover, in the total absence of any fitting procedure, the results show excellent agreement with experimental data reported in the literature. Thus, this paper opens new pathways for the global optimization problem of extreme ultraviolet (EUV) sources based on HHG. PMID:19550522

Falcão-Filho, E L; Gkortsas, M; Gordon, Ariel; Kärtner, Franz X

2009-06-22

39

Some Aspects of the Harmonic Analysis of Irregularly Spaced Data.  

National Technical Information Service (NTIS)

An investigation into the effect of irregular spacing of data upon harmonic coefficients is presented. The statistical model for the irregularity of the spacing is subject to certain constraints. The coefficients of each harmonic are calculated individual...

E. P. Avara M. Kays

1970-01-01

40

Analysis of high frequency partials in Bayesian harmonic model  

Microsoft Academic Search

Bayesian harmonic modeling and parameters estimation is a new approach in audio signal synthesizing. However current Bayesian harmonic modeling canpsilat effectively extract high frequency partials. In this paper we propose an improved model with parameters of high frequency partials for audio signal with harmonic modeling. We estimate partials in a Bayesian framework with the prior knowledge and likelihood function of

Jinghua Yan; Hui Wang; Chuanzhen Li; Qin Zhang

2008-01-01

41

A salient-pole generator model for harmonic analysis  

Microsoft Academic Search

This paper describes the derivation of a salient-pole synchronous generator harmonic model in the form of a harmonically coupled impedance matrix. In sequence components, the relationship between the generator harmonic voltages and currents in the presence of saliency can be represented by analytical expressions, which are derived from the normally available machine parameters such as direct and quadrature-axis subtransient reactances.

Nhut-Quang Dinh; Jos Arrillaga

2001-01-01

42

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

43

Identifying aquifer type in fractured rock aquifers using harmonic analysis.  

PubMed

Determining aquifer type, unconfined, semi-confined, or confined, by drilling or performing pumping tests has inherent problems (i.e., cost and complex field issues) while sometimes yielding inconclusive results. An improved method to cost-effectively determine aquifer type would be beneficial for hydraulic mapping of complex aquifer systems like fractured rock aquifers. Earth tides are known to influence water levels in wells penetrating confined aquifers or unconfined thick, low-porosity aquifers. Water-level fluctuations in wells tapping confined and unconfined aquifers are also influenced by changes in barometric pressure. Harmonic analyses of water-level fluctuations of a thick (~1000 m) carbonate aquifer located in south-central Oklahoma (Arbuckle-Simpson aquifer) were utilized in nine wells to identify aquifer type by evaluating the influence of earth tides and barometric-pressure variations using signal identification. On the basis of the results, portions of the aquifer responded hydraulically as each type of aquifer even though there was no significant variation in lithostratigraphy. The aquifer type was depth dependent with confined conditions becoming more prevalent with depth. The results demonstrate that harmonic analysis is an accurate and low-cost method to determine aquifer type. PMID:22463080

Rahi, Khayyun A; Halihan, Todd

2012-03-28

44

Fourier analysis of harmonic frequency transmission dielectric structures  

NASA Astrophysics Data System (ADS)

We use an analytical calculation based on the Fourier-transform method to study the transmission spectra of multilayer dielectric optical structures as a function of the relative widths of the layers that constitute the unit cell. We can select which harmonics of the fundamental design frequency are transmitted. The results of this Fourier-transform approach are compared with the exact transmission calculated by means of the transfer matrix method and provide a more intuitive understanding of the transmission spectrum. A simple phasor diagram is derived from this Fourier-transform analysis for this purpose. Inasmuch as it is difficult for us to perform experiments in the optical region, we fabricate rf analogs of these structures, using coaxial cables that have different impedances. Experimental results agree with theory.

del Mar Sánchez-López, María; Cos, Joaquín; Davis, Jeffrey A.; Miller, Darren A.; Moreno, Ignacio

2005-06-01

45

Harmonic analysis of slip energy recovery induction motor drives  

SciTech Connect

The impact of drives on the power system in terms of harmonic generation is becoming increasingly important. Slip energy recover induction motor drives (SERIMDs) have the rectifier and inverter connected to the rotor instead of the stator (the case in most conventional drives). The harmonic content of the SERIMD is thus quite different and arguably, less onerous than conventional drives. This paper examines the harmonic content of key waveforms of SERIMDs. Predicted results are supported by extensive experimental results.

Refoufi, L. (Inst. National D'Electricite, Boumerdes (Algeria)); Pillay, P. (Univ. of New Orleans, LA (United States). Dept. of Electrical Engineering)

1994-12-01

46

Harmonic analysis of multi-phase electric-power distribution systems  

Microsoft Academic Search

This study presents a computer program as a tool for the harmonic analysis of multi-phase electric power distribution systems. In the program, the source of harmonics can be any number of multi-phase harmonic currents and\\/or voltages, or up to 10 three-phase converts. Frequency-dependent models of ac network elements are assembled into a sparse admittance matrix. Then, sparsity techniques are employed

Hosseini

1988-01-01

47

Analysis of sub-harmonics in power systems  

Microsoft Academic Search

With a wide range of power electronics-related applications in power systems, harmonic currents are increasing at an alarming rate which has greatly deteriorated the power quality in electrical power networks. Moreover, some of electronic controlled equipments used in power systems, such as power converters, produce sub-harmonics, a type of waveform distortion, which can severely degrade the power system performance. Therefore,

Zbigniew Leonowicz

2010-01-01

48

Harmonic analysis of the repulsion motor controlled via rotor triac  

Microsoft Academic Search

The authors investigate the harmonic contents of the stator current, rotor current, and rotor voltage of a repulsion motor controlled by a triac in the rotor circuit. The waveforms of these variables were generated and then analyzed numerically for their harmonic content using a Fourier series subroutine. The results were validated by comparison with experimental results. The analyses show that

Ziyad M. Salameh; John W. Kilgo

1989-01-01

49

Harmonic analysis of multi-phase electric-power distribution systems  

SciTech Connect

This study presents a computer program as a tool for the harmonic analysis of multi-phase electric power distribution systems. In the program, the source of harmonics can be any number of multi-phase harmonic currents and/or voltages, or up to 10 three-phase converts. Frequency-dependent models of ac network elements are assembled into a sparse admittance matrix. Then, sparsity techniques are employed to determine the current flow in all elements and voltages at all busses throughout the system at any harmonic frequency up to 3 KHz. Voltage distortion factors that represent the overall effects of the harmonics of the system voltages are also calculated. The digital program was then applied to a multi-phase distribution system in order to observe the response of the system to the various changes that were made in the system. It was found that the converter size and location, the capacitor bank sizes and locations, and the representation of the system loads are factors in determining in harmonic current flows and the level of voltage-distortion factors. Also, the response of the system to single-phase harmonic sources was investigated, and it was discovered that the effects of single-phase harmonic sources can be serious enough that they should not be ignored in the harmonic analysis of multi-phase systems.

Hosseini, S.H.

1988-01-01

50

Harmonic analysis utilizing a Phonodeik and an Henrici analyzer  

NASA Astrophysics Data System (ADS)

Dayton C. Miller of the Case School of Applied Science assembled a series of instruments for accurate analysis of sound [D. C. Miller, J. Franklin Inst. 182, 285-322 (1916)]. He created the Phonodeik to display and record sound waveforms of musical instruments, voices, fog horns, and so on. Waveforms were analyzed with the Henrici harmonic analyzer, built in Switzerland by G. Coradi. In this device, the motion of a stylus along the curve to be analyzed causes a series of spheres to rotate; two moveable rollers in contact with the nth sphere record the contributions of the sine(nx) and cosine(nx) components of the wave. Corrections for the measured spectra are calculated from analysis of the response of the Phonodeik. Finally, the original waveform could be reconstructed from the corrected spectral amplitudes and phases by a waveform synthesizer, also built at Case. Videos will be presented that show the motion of the gears, spheres, and dials of a working Henrici analyzer, housed at the Department of Speech Pathology and Audiology at the University of Iowa. Operation of the Henrici analyzer and the waveform synthesizer will be explained.

Fickinger, William J.; Hanson, Roger J.; Hoekje, Peter L.

2001-05-01

51

Harmonic analysis of nondeterministic switching methods for DC-DC power converters  

Microsoft Academic Search

The authors present a rigorous theoretical harmonic analysis of random pulse width modulation (RPWM) method and random pulse position modulation (RPPM) method for dc-dc converters. The theoretical relationships of discrete harmonics, continuous noise and output voltage ripple of the RPWM and RPPM schemes are established and compared with those of a standard deterministic PWM scheme in a buck converter. Limitations

Yash Shrivastava; S. Y. Hui; S. Sathiakumar; H. Shu-Hung Chung; K. K. Tse

2000-01-01

52

An induction motor speed measurement based on current harmonic analysis with Chirp-Z Transform  

Microsoft Academic Search

The paper presents a new method to measure motor speed by means of frequency estimation of rotor slot harmonics present in the supply current of squirrel single cage induction motors. The novelty of the method is the use of Chirp-Z Transform as supply current harmonic analysis. The advantages are an improved spectral resolution and accuracy. Moreover a shorter sampling time

M. Aiello; A. Cataliotti; S. Nuccio

2001-01-01

53

Harmonic analysis and simulation of high frequency inverter system in Fuel Cell Engine  

Microsoft Academic Search

For the Fuel Cell Engine, the air compressor driving motor is controlled by high frequency inverter system. Because of the period interruption caused by commutation and limitation of the switch frequency, there are more harmonic components in inverter during high frequency region. In this paper, harmonic analysis and simulation are presented in different voltage modulation techinques. The simulation results indicated

Baiqing Sun; Qiancheng Zhao; Jinhu Shen; Qiuhao Zhang

2011-01-01

54

Harmonic analysis of force platform data in normal and cerebral palsy gait  

Microsoft Academic Search

Background. Examination of force platform data during gait is usually carried out in the time domain and is limited to selected points on the force–time graphs. Harmonic analysis allows examination of the whole waveform and has a greater potential for assessing the effects of treatment options. Therefore, the objectives of this study were to show the benefits of using harmonic

R. White; I. Agouris; E. Fletcher

2005-01-01

55

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

NASA Astrophysics Data System (ADS)

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.

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

1987-09-01

56

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

57

Completion report harmonic analysis of electrical distribution systems.  

National Technical Information Service (NTIS)

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 wav...

L. M. Tolbert

1996-01-01

58

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

59

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

NASA Astrophysics Data System (ADS)

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

Asija, Pal

2006-03-01

60

Spherical harmonic analysis of steady photospheric flows. II  

NASA Astrophysics Data System (ADS)

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

Hathaway, David H.

1992-01-01

61

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

62

Harmonic analysis of iterated function systems with overlap  

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

63

Comparison of the Results between APLAC and HP MDS. Part A: Transient Analysis and Harmonic Balance.  

National Technical Information Service (NTIS)

This work presents a comparison of the transient analysis and harmonic balance between APLAC and HP MDS. The comparison is carried out with examples. The examples use only simple models for diodes, resistance, capacitances, inductances, and microstrip com...

H. Jokinen S. Haikarainen J. Kiraly S. Kalajo M. Valtonen

1996-01-01

64

On the aliasing problem in the spherical harmonic analysis  

NASA Astrophysics Data System (ADS)

To apply the least squares method for the interpolation of harmonic functions is a common practice in Geodesy. Since the method of least squares can be applied only to overdetermined problem, the interpolation problem which is always under-determined, is often reduced to an overdetermined form by truncating a series of spherical harmonics. When the data points are the knots of a regular grid it is easy to see that the estimated harmonic coefficients converge to the correct theoretical values, but when the observation density is not constant a significant bias is introduced. The result is obtained by assuming that the number of observations tends to infinity with points sampled from a given distribution. Under the same conditions it is shown that quadrature and “collocation-like” formulas displays a statistically consistent behaviour.

Sansò, F.

1990-12-01

65

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

NSDL National Science Digital Library

This student workbook is part of a set of workbooks designed to serve as the foundation for a two-semester calculus-based introductory physics course consisting of 28 units that interweave text materials with activities that include prediction, qualitative observation, explanation, equation derivation, mathematical modeling, quantitative experiments, and problem solving. This workbook covers momentum, energy, rotational and harmonic motion, and chaos.

Laws, Priscilla W.

2006-07-22

66

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

SciTech Connect

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

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

1992-10-01

67

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

68

Bayesian harmonic models for musical pitch estimation and analysis  

Microsoft Academic Search

Estimating the pitch of musical signals is complicated by the presence of partials in addition to the fundamental frequency. In this paper, we propose developments to an earlier Bayesian model which describes each component signal in terms of fundamental frequency, partials (‘harmonics’), and amplitude. This basic model is modified for greater realism to include non-white residual spectrum, time-varying amplitudes and

Simon Godsill; Manuel Davy

2002-01-01

69

Harmonic Phasor Analysis Based on Improved FFT Algorithm  

Microsoft Academic Search

Anapproachforpowersystemharmonicphasoranal- ysis under asynchronous sampling is proposed in this paper. It is basedonsmoothingsampleddatabywindowingthesignalwiththe four-term fifth derivative Nuttall (FFDN) window, and then cal- culating harmonic phasors in the frequency domain with an im- proved fast Fourier transform (IFFT) algorithm. The applicable rectification formulas of the IFFT are obtained by using the poly- nomial curve fitting, dramatically reducing the computation load. The

Bo Zeng; Zhaosheng Teng; Yulian Cai; Siyu Guo; Baiyuan Qing

2011-01-01

70

The error analysis and harmonic wave correction of inductosyn  

Microsoft Academic Search

In this paper, the precision of the inductosyn had been improved through study error characteristics of inductosyn and use error harmonic wave correction method. First The long period error and short period error of the inductosyn have been studied. And the study result is that the long period error mainly includes the first order error and secondary error in the

Wang xianquan; Wu min; Zhu ge; Feng jiqin

2010-01-01

71

Information criteria and harmonic models in time series analysis  

Microsoft Academic Search

In this paper we present a novel methodology for estimating harmonic models in time series. The amplitude density function is derived from an inversion of the spectral representation of the series and is found to have the property of strong consistency. It is used in conjunction with non-linear least squares regression in an iterative procedure to yield precise estimates of

Dominique Haughton; Jonathan Haughton; Alan J. Izenman

1990-01-01

72

Theoretical analysis of cancellation of DC-link current harmonics in the inverter-controlled DC electric railcar  

Microsoft Academic Search

This paper presents the theoretical studies on the DC-link current harmonics in the inverter-controlled DC electric railcar. First, we derive the mathematical expression of the harmonics. And comparison among a theoretical result, a numerical simulation result, and an experimental result is also presented for verification of the proposed theoretical analysis. Then this paper examines the harmonic cancellation effect of the

Tomoyuki Ogawa; Shinji Wakao; Jat Taufiq; Keiichiro Kondo; Nobuo Terauchi

2007-01-01

73

Bioimpedance harmonic analysis as a tool to simultaneously assess circulation and nervous control.  

PubMed

Multicycle harmonic (Fourier) analysis of bioimpedance was employed to simultaneously assess circulation and neural activity in visceral (rat urinary bladder) and somatic (human finger) organs. The informative value of the first cardiac harmonic of the bladder impedance as an index of bladder circulation is demonstrated. The individual reactions of normal and obstructive bladders in response to infusion cystometry were recorded. The potency of multicycle harmonic analysis of bioimpedance to assess sympathetic and parasympathetic neural control in urinary bladder is discussed. In the human finger, bioimpedance harmonic analysis revealed three periodic components at the rate of the heart beat, respiration and Mayer wave (0.1 Hz), which were observed under normal conditions and during blood flow arrest in the hand. The revealed spectrum peaks were explained by the changes in systemic blood pressure and in regional vascular tone resulting from neural vasomotor control. During normal respiration and circulation, two side cardiac peaks were revealed in a bioimpedance amplitude spectrum, whose amplitude reflected the depth of amplitude respiratory modulation of the cardiac output. During normal breathing, the peaks corresponding to the second and third cardiac harmonics were split, reflecting frequency respiratory modulation of the heart rate. Multicycle harmonic analysis of bioimpedance is a novel potent tool to examine the interaction between the respiratory and cardiovascular system and to simultaneously assess regional circulation and neural influences in visceral and somatic organs. PMID:21646716

Mudraya, I S; Revenko, S V; Nesterov, A V; Gavrilov, I Yu; Kirpatovsky, V I

2011-06-07

74

High-frequency harmonic distortion in feedback amplifiers: analysis and applications  

Microsoft Academic Search

An approach for the evaluation of high-frequency harmonic-distortion factors in feedback systems is proposed and the results obtained are applied to feedback amplifiers. Under the assumption that transistors are not driven out of their linear operating regions, small-signal analysis and conventional algebra are exploited to derive understandable and compact expressions highly improving the comprehension of harmonic-distortion generation. The impact of

Gaetano Palumbo; Salvatore Pennisi

2003-01-01

75

Analysis of Class-E Based RF Power Amplifiers Using Harmonic Modeling  

Microsoft Academic Search

An analysis of the Class-E power amplifier is given using harmonic modeling that facilitates its characterization for a wide load-space regime expected in applications such as RF plasma generation for semiconductor manufacturing. Using a hybrid matrix-framework made up of the dominant harmonics of the circuit variables aided by the time-domain boundary conditions of the power switch voltage waveform, a quasi-linear

Seshadri Sivakumar; Abdullah Eroglu

2010-01-01

76

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

77

Completion report harmonic analysis of electrical distribution systems  

Microsoft Academic Search

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

Tolbert

1996-01-01

78

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.

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

2012-01-01

79

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

80

Harmonic Resonance Analysis for PEP II Power Factor Control Upgrades  

NASA Astrophysics Data System (ADS)

Recent upgrades to the high voltage utility distribution network at the Stanford Linear Accelerator Center have been accompanied by the installation of a large number of power supplies associated with the PEP-II B Factory project. These power supplies include a diverse assortment of single and three phase units, in two, six and twelve pulse configurations, with chopped, pulsed and continuous loading. Viewed as harmonic power sources in a range from a hundred to several kilohertz, they have the potential to be in resonance with the utility system network, a condition to be avoided. This paper analyzes and evaluates these resonance conditions with a view toward adding electric power factor correction upgrades to achieve substantial cost savings associated with power factor penalty avoidance. Similar studies and upgrades at SLAC in the past have reduced electric power costs over time by several hundred thousand dollars, thus providing the incentive to evaluate the recent upgrades to the PEP-II utility network.

Corvin, C.

1997-05-01

81

Harmonic analysis of the DTU10 global gravity anomalies  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

82

Quantitative analysis of biological tissues using Fourier transform-second-harmonic generation imaging  

NASA Astrophysics Data System (ADS)

We demonstrate the use of Fourier transform-second-harmonic generation (FT-SHG) imaging of collagen fibers as a means of performing quantitative analysis of obtained images of selected spatial regions in porcine trachea, ear, and cornea. Two quantitative markers, preferred orientation and maximum spatial frequency are proposed for differentiating structural information between various spatial regions of interest in the specimens. The ear shows consistent maximum spatial frequency and orientation as also observed in its real-space image. However, there are observable changes in the orientation and minimum feature size of fibers in the trachea indicating a more random organization. Finally, the analysis is applied to a 3D image stack of the cornea. It is shown that the standard deviation of the orientation is sensitive to the randomness in fiber orientation. Regions with variations in the maximum spatial frequency, but with relatively constant orientation, suggest that maximum spatial frequency is useful as an independent quantitative marker. We emphasize that FT-SHG is a simple, yet powerful, tool for extracting information from images that is not obvious in real space. This technique can be used as a quantitative biomarker to assess the structure of collagen fibers that may change due to damage from disease or physical injury.

Ambekar Ramachandra Rao, Raghu; Mehta, Monal R.; Toussaint, Kimani C., Jr.

2010-02-01

83

High order harmonics from mid-infrared drivers for attosecond physics  

SciTech Connect

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

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

2009-09-10

84

Spatial analysis of harmonic oscillation of gypsy moth outbreak intensity.  

PubMed

Outbreaks of many forest-defoliating insects are synchronous over broad geographic areas and occur with a period of approximately 10 years. Within the range of the gypsy moth in North America, however, there is considerable geographic heterogeneity in strength of periodicity and the frequency of outbreaks. Furthermore, gypsy moth outbreaks exhibit two significant periodicities: a dominant period of 8-10 years and a subdominant period of 4-5 years. In this study, we used a simulation model and spatially referenced time series of outbreak intensity data from the Northeastern United States to show that the bimodal periodicity in the intensity of gypsy moth outbreaks is largely a result of harmonic oscillations in gypsy moth abundance at and above a 4 km(2) scale of resolution. We also used geographically weighted regression models to explore the effects of gypsy moth host-tree abundance on the periodicity of gypsy moths. We found that the strength of 5-year cycles increased relative to the strength of 10-year cycles with increasing host tree abundance. We suggest that this pattern emerges because high host-tree availability enhances the growth rates of gypsy moth populations. PMID:18985391

Haynes, Kyle J; Liebhold, Andrew M; Johnson, Derek M

2008-11-05

85

The Studies on Power System Harmonic Analysis based on Extended Prony Method  

Microsoft Academic Search

A new harmonics analysis method based on extended Prony method and distributed Ethernet network is proposed. The new method uses an extended Prony algorithm to estimate the amplitudes and phase angles from the distorted currents in power systems. The extended Prony algorithm uses a linear combination of exponential functions to imitate signals. It can calculate the amplitudes, phase angles, damp

Zhijian Hu; Jianquang Guo; Mei Yu; Zhiwei Du; Chao Wang

2006-01-01

86

Column and row operator spaces over QSL p -spaces and their use in abstract harmonic analysis  

Microsoft Academic Search

The notions of column and row operator space were extended by A. Lambert from Hilbert spaces to general Banach spaces. In this paper, we use column and row spaces over quotients of subspaces of general Lp-spaces to equip several Banach algebras occurring naturally in abstract harmonic analysis with canonical, yet not obvious operator space structures that turn them into completely

Matthias Neufang; Volker Runde

2009-01-01

87

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

Microsoft Academic Search

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

A. Gover; A. Friedman; A. Luccio

1986-01-01

88

Three Dimensional Modelling and Numerical Analysis of Super-Radiant Harmonic Emission in FEL (Optical Klystron).  

National Technical Information Service (NTIS)

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 rad...

A. Gover A. Friedman A. Luccio

1986-01-01

89

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

90

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

91

Data Analysis in Physics Examination  

ERIC Educational Resources Information Center

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

Forster, Patricia A.

2005-01-01

92

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

NASA Astrophysics Data System (ADS)

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

Kramer, Peter

2010-02-01

93

Rectenna Design and Optimization Using Reciprocity Theory and Harmonic Balance Analysis for Electromagnetic (EM) Energy Harvesting  

Microsoft Academic Search

A rectenna design methodology combining electromagnetic (EM) simulation and harmonic balance (HB) analysis is presented. It consists of applying reciprocity theory to calculate the Thevenin equivalent circuit of the receiving antenna and optimizing the rectifying circuit parameters using HB analysis. The method is demonstrated by designing a 2.45-GHz rectenna based on a square aperture-coupled patch antenna with dual linear polarization.

A. Georgiadis; G. Andia; A. Collado

2010-01-01

94

Study about the current oscillating and harmonic analysis of high frequency chopped wave cascade speed control system  

Microsoft Academic Search

The chopped wave cascade speed control system is a promising lower energy consumption and reduce pollutants discharging technology. Because the electronics and electric devices are adopted to be its kernel component, it is one of the main harmonic sources for the power grid, and consuming lots of reactive power. The analysis and calculation about its harmonics could be used to

Zhang JunWei; Wang Bingshu

2010-01-01

95

From self-adjoint to non-self-adjoint harmonic oscillators: Physical consequences and mathematical pitfalls  

NASA Astrophysics Data System (ADS)

Using as a prototype example the harmonic oscillator we show how losing self-adjointness of the Hamiltonian H changes drastically the related functional structure. In particular, we show that even a small deviation from strict self-adjointness of H produces two deep consequences, not well understood in the literature: First of all, the original orthonormal basis of H splits into two families of biorthogonal vectors. These two families are complete but, contrarily to what often claimed for similar systems, none of them is a basis for the Hilbert space H. Second, the so-called metric operator is unbounded, as well as its inverse. In the second part of the paper, after an extension of some previous results on the so-called D pseudobosons, we discuss some aspects of our extended harmonic oscillator from this different point of view.

Bagarello, F.

2013-09-01

96

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

97

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

98

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

99

Acoustical analysis of woodwind musical instruments for virtual instrument implementation by physical modeling  

Microsoft Academic Search

In the present paper, we present the development of a framework of methodologies, which allow the creation of acoustic analysis, by woodwind musical instrument recordings corpora, as well as the implementation of virtual instruments, by physical modeling. We emphasize on traditional instruments, starting with the zournas. By analysis, acoustical aspects of the instrument are derived (attack-release time, spectral harmonic distribution,

Panagiotis Tzevelekos; Georgios Kouroupetroglou

2004-01-01

100

Harmonic generation beyond the Strong-Field Approximation: the physics behind the short-wave-infrared scaling laws.  

PubMed

The physics of laser-mater interactions beyond the perturbative limit configures the field of extreme non-linear optics. Although most experiments have been done in the near infrared ( lambda harmonic generation. We discuss the physical grounds, provide a theoretical framework beyond the standard approximations and develop a compact approach that accounts for the correct scaling of the harmonic yield. PMID:19506639

Pérez-Hernández, J A; Roso, L; Plaja, L

2009-06-01

101

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

102

Analysis of large clock meshes via Harmonic-weighted model order reduction and port sliding  

Microsoft Academic Search

Clock meshes posses inherent low clock skews and excellent immunity to PVT variations, and have increasingly found their way to high-performance IC designs. However, analysis of such massively coupled networks is significantly hindered by the sheer size of the network and tight coupling between non-tree interconnects and large numbers of clock drivers. The presented Harmonic-weighted model order reduction algorithm is

Xiaoji Ye; Peng Li; Min Zhao; Rajendran Panda; Jiang Hu

2007-01-01

103

Analysis of large clock meshes via harmonic-weighted model order reduction and port sliding  

Microsoft Academic Search

ó Clock meshes posses inherent low clock skews and excellent immunity to PVT variations, and have increasingly found their way to high-performance IC designs. However, analysis of such massively coupled networks is signicantly hindered by the sheer size of the network and tight coupling between non-tree interconnects and large numbers of clock drivers. The presented Harmonic-weighted model order reduction algorithm

Xiaoji Ye; Peng Li; Min Zhao; Rajendran Panda; Jiang Hu

2007-01-01

104

Magnetic measurement system for harmonic analysis of LBL SSC model dipoles and quadrupoles  

Microsoft Academic Search

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 buckling ratios that also have sufficient sensitivity to make room-temperature measurements at the low magnet currents of --10 A. Three sets of search coils allow measurements of

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

1988-01-01

105

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

Microsoft Academic Search

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

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

1987-01-01

106

An analysis of nonlinear normal contact microvibrations excited by a harmonic force  

Microsoft Academic Search

This paper presents the results of numerical investigations of nonlinear normal contact microvibrations excited by a harmonic\\u000a force in a system of two bodies in planar contact that models the slideway connections of machine tools. The aim of the computation\\u000a analysis was to determine the plots of the forced vibrations as a function of frequency and amplitude and to study

Karol Grudzi?ski; Robert Kostek

2007-01-01

107

A synchronous machine model for three-phase harmonic analysis and EMTP initialization  

Microsoft Academic Search

A three-phase synchronous machine model is developed for unbalanced harmonic load flow analysis and for initializing EMTP (electromagnetic transient program) transient simulations. Two nonlinear effects, the frequency conversion and saturation, are represented in conjunction with the machine load flow constraints. The model is in the form of a frequency-dependent three-phase equivalent circuit. It can therefore be easily incorporated into existing

Wilsun W. Xu; H. W. Dommel; Jose R. Marti

1991-01-01

108

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

109

Multiple harmonic plasma emission  

SciTech Connect

A generalized weak turbulence theory for electromagnetic emission at multiple harmonics of the plasma frequency is developed. In the literature, the electromagnetic emission at the plasma frequency and/or its second harmonic has been intensively studied. However, the emission at harmonics higher than the second harmonic is scarcely discussed. In the present paper, the higher harmonic plasma emission is explained by taking the interactions between the transverse mode and electrostatic nonlinear eigenmodes into consideration. The present analysis incorporates electrostatic nonlinear harmonic Langmuir waves into the fully electromagnetic weak turbulence formalism recently reformulated on the basis of the statistical mechanical Klimontovich approach. The wave kinetic equations for the transverse electromagnetic and Langmuir waves interacting with the harmonic Langmuir waves are derived, on the basis of which the emission of electromagnetic waves near multiple harmonics of the plasma frequency is qualitatively discussed.

Yi, Sumin; Yoon, Peter H.; Ryu, Chang-Mo [Department of Physics, Pohang University of Science and Technology, Pohang (Korea, Republic of); Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); Department of Physics, Pohang University of Science and Technology, Pohang (Korea, Republic of)

2007-01-15

110

The space physics analysis network  

NASA Astrophysics Data System (ADS)

The Space Physics Analysis Network, or SPAN, is emerging as a viable method for solving an immediate communication problem for space and Earth scientists and has been operational for nearly 7 years. SPAN and its extension into Europe, utilizes computer-to-computer communications allowing mail, binary and text file transfer, and remote logon capability to over 1000 space science computer systems. The network has been used to successfully transfer real-time data to remote researchers for rapid data analysis but its primary function is for non-real-time applications. One of the major advantages for using SPAN is its spacecraft mission independence. Space science researchers using SPAN are located in universities, industries and government institutions all across the United States and Europe. These researchers are in such fields as magnetospheric physics, astrophysics, ionosperic physics, atmospheric physics, climatology, meteorology, oceanography, planetary physics and solar physics. SPAN users have access to space and Earth science data bases, mission planning and information systems, and computational facilities for the purposes of facilitating correlative space data exchange, data analysis and space research. For example, the National Space Science Data Center (NSSDC), which manages the network, is providing facilities on SPAN such as the Network Information Center (SPAN NIC). SPAN has interconnections with several national and international networks such as HEPNET and TEXNET forming a transparent DECnet network. The combined total number of computers now reachable over these combined networks is about 2000. In addition, SPAN supports full function capabilities over the international public packet switched networks (e.g. TELENET) and has mail gateways to ARPANET, BITNET and JANET.

Green, James L.

1988-04-01

111

Exponential analysis in physical phenomena  

NASA Astrophysics Data System (ADS)

Many physical phenomena are described by first-order differential equations whose solution is an exponential decay. Determining the time constants and amplitudes of exponential decays from the experimental data is a common task in semiconductor physics (deep level transient spectroscopy), biophysics (fluorescence decay analysis), nuclear physics and chemistry (radioactive decays, nuclear magnetic resonance), chemistry and electrochemistry (reaction kinetics) and medical imaging. This review article discusses the fundamental mathematical limitations of exponential analysis, outlines the critical aspects of acquisition of exponential transients for subsequent analysis, and gives a comprehensive overview of numerical algorithms used in exponential analysis. In the first part of the article the resolution of exponential analysis as a function of noise in input decays is discussed. It is shown that two exponential decays can be resolved in a transient only if the ratio of their time constants is greater than the resolution limit, which can be explicitly calculated from the signal-to-noise ratio in the transient. Although the signal-to-noise ratio is generally limited by the sensitivity of the equipment, it is shown that digitalization of the decays may be a major source of noise. The requirements for type of analog-to-digital converter, number of digitized data points and duration of digitized transients, which must be met to obtain the theoretical resolution limit and to improve stability of the exponential analysis, are formulated. The second part of the review article gives an overview and comparison of major numerical techniques of exponential analysis, such as the nonlinear least squares fit, the Prony method, the method of modulating functions, the method of moments, the Laplace-Padé approximation, the Tikhonov regularization method, the Gardner transformation, the method of maximum entropy and others.

Istratov, Andrei A.; Vyvenko, Oleg F.

1999-02-01

112

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

SciTech Connect

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

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

1999-09-01

113

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

NASA Astrophysics Data System (ADS)

Improved core high-harmonic fast wave (HHFW) heating, particularly at longer wavelengths and during low-density start-up and current ramp-up, has now been obtained by lowering the edge density with lithium conditioning, thereby moving the propagation onset away from the vessel wall. Significant core electron heating of deuterium neutral beam injection (NBI) fuelled H-modes has been observed for the first time over a range of launched wavelengths. The observed broadening of the electron heating profile in H-mode relative to L-mode plasmas is consistent with simulations obtained with ray tracing and full wave models. Newly taken camera images indicate that fast wave interactions can deposit considerable RF energy on the outboard divertor plate, especially at longer wavelengths that begin to propagate closer to the vessel walls. Edge power loss can also arise from HHFW-generated parametric decay instabilities that drive ions in the edge onto direct loss orbits that intersect the wall, and may be the cause for an observed drag on edge toroidal rotation in combined HHFW and NBI discharges. Fast-Ion D-alpha emission clearly shows fast-ion profile broadening in the plasma core that is much greater than predicted by Fokker-Planck modeling when HHFW power is applied to NBI-fuelled plasmas, pointing to the need for a full-orbit treatment in the simulation. Large ELMs have been observed immediately following the termination of RF power, whether the power turn off is programmed or due to antenna arcing. RF power has been successfully applied during large ELMs by setting the source reflection coefficient trip levels to relatively high values -- an approach potentially important for ITER ICRF heating. Plans for an HHFW ELM-resilience upgrade will be presented.

Taylor, Gary

2009-11-01

114

Second harmonic generation analysis in hydrogenated amorphous silicon nitride thin films  

SciTech Connect

Surface and interface electronic properties of plasma-deposited hydrogenated amorphous silicon nitride films have been investigated by means of optical second harmonic generation (SHG) technique. Polarization analysis shows that the nonlinear field origins from isotropic interfaces (film/substrate interface and film/air interface) whose spectral features are ascribed to surface/interface Si dangling bonds and strained Si-Si bonds. Differences and similarities with SHG spectra of pure amorphous silicon (a-Si:H) are discussed in terms of compositional inhomogeneities of the ternary alloy.

Lettieri, S.; Merola, F.; Maddalena, P.; Ricciardi, C.; Giorgis, F. [CNR-INFM Coherentia-Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II' Via Cintia, 80126 Naples (Italy); Dipartimento di Fisica, Laboratorio Materiali e Microsistemi, Politecnico di Torino C.so Duca degli Abruzzi 24, 10129 Turin (Italy)

2007-01-08

115

[Harmonic physical development of children in the town of Gomel in the post-Chernobyl period].  

PubMed

The results of investigation of the harmony of physical development of children living in Gomel (the density of Cs137 territory contamination is 1-5 Ci/km2) are presented. Age and sex characteristics of body mass and body length variations, annual mass gains, the mass and length parameter and the harmony of physical development are assessed. A significant proportion of the children have manifested disharmonious and sharply disharmonious development due both to the excess or deficiency of body mass of the 1st and 2nd categories. PMID:10486814

Kienia, A I; Zaika, E M; Kirichenko, O V

1999-01-01

116

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

117

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

118

Discovering new physics in magnetic thin films using coherent EUV from high harmonic generation  

NASA Astrophysics Data System (ADS)

The understanding of nanoscale magnetism has become much more critical with recent advances in magnetic data storage applications, as bits on a hard disk are already packed at scales of about 20nm. However, a microscopic model of how spins, electrons, photons and phonons interact does not yet exist. This understanding is fundamentally constrained in large part by our limited ability to observe magnetism on all relevant time and length scales. Until recently, measuring magnetization dynamics used either ultrafast visible-wavelength lasers, or X-rays from synchrotrons and free electron lasers. Our recent work has shown that the fastest dynamics in magnetic materials can be captured using extreme ultraviolet (XUV) harmonics -- with elemental resolution and at multiple atomic sites simultaneously. We first probed with elemental sensitivity how fast the magnetic state can be destroyed in an Fe-Ni alloy. After exciting an Fe-Ni alloy with a fs laser, the spin sublattices randomize on sub-ps timescales. Surprisingly, even in a strongly coupled ferromagnetic alloy, the demagnetization of Ni lags that of Fe by 10 fs [1]. Moreover, we were able to tune this time lag by diluting the alloy with Cu to further reduce the exchange energy. After a time lag characteristic of the exchange energy, the Ni sublattice demagnetizes at the same rate as Fe. This reveals both how the exchange interaction can mediate ultrafast magnetic dynamics in alloys, and how the intrinsic demagnetization process is site-specific such that spins on one sublattice can interact more strongly with the optical field than spins on the other sublattice. In our latest work, we uncovered evidence of giant spin-currents in magnetic multilayers that are generated in the course of the laser-driven ultrafast demagnetization process [2]. By exciting a magnetic multilayer (Fe/Ru/Ni) with a laser pulse, and separately, yet simultaneously, probing the magnetization response of the Ni and Fe layers when the two layers are aligned with an applied magnetic field, we found that optically induced demagnetization of the top Ni layer causes the buried Fe layer to undergo a transient enhancement of the magnetization, of up to 20 percent. This is due to an intense, majority spin-current that enters the Fe layer. [4pt] [1] S. Mathias, et al., PNAS 109, (2012).[0pt] [2] D. Rudolf, et al., Nat. Comm. 3, (2012).

Silva, Tom

2013-03-01

119

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

Microsoft Academic Search

In a high-gain free-electron laser (FEL) employing a planar undulator, strong bunching at the fundamental wavelength can drive substantial bunching and power levels at the harmonic frequencies. In this paper we investigate the three-dimensional evolution of harmonic radiation based on the coupled Maxwell-Klimontovich equations that take into account nonlinear harmonic interactions. Each harmonic field is a sum of a linear

Zhirong Huang; Kwang-Je Kim

2000-01-01

120

Theoretical analysis of return current harmonics in the inverter-controlled DC electric railcar  

Microsoft Academic Search

The harmonics of the return current may interfere with the signaling current along with the rails. In order to investigate the index of the compatibility with the signaling current, the theoretical investigation of the return current harmonics is preferable rather than expensive and time consuming experimental study. In this paper, we present the theoretical studies of the return current harmonics

T. Ogawa; S. Wakao; K. Kondo; N. Terauchi

2004-01-01

121

GENERAL: Stability Analysis of an Inverted Pendulum Subjected to Combined High Frequency Harmonics and Stochastic Excitations  

Microsoft Academic Search

Stability of vertical upright position of an inverted pendulum with its suspension point subjected to high frequency harmonics and stochastic excitations is investigated. Two classes of excitations, i.e., combined high frequency harmonic excitation and Gaussian white noise excitation, and high frequency bounded noise excitation, respectively, are considered. Firstly, the terms of high frequency harmonic excitations in the equation of motion

Zhi-Long Huang; Xiao-Ling Jin; Zi-Qi Zhu

2008-01-01

122

An approach for spherical harmonic analysis of non-smooth data  

NASA Astrophysics Data System (ADS)

A method is proposed to evaluate the spherical harmonic coefficients of a global or regional, non-smooth, observable dataset sampled on an equiangular grid. The method is based on an integration strategy using new recursion relations. Because a bilinear function is used to interpolate points within the grid cells, this method is suitable for non-smooth data; the slope of the data may be piecewise continuous, with extreme changes at the boundaries. In order to validate the method, the coefficients of an axisymmetric model are computed, and compared with the derived analytical expressions. Numerical results show that this method is indeed reasonable for non-smooth models, and that the maximum degree for spherical harmonic analysis should be empirically determined by several factors including the model resolution and the degree of non-smoothness in the dataset, and it can be several times larger than the total number of latitudinal grid points. It is also shown that this method is appropriate for the approximate analysis of a smooth dataset. Moreover, this paper provides the program flowchart and an internet address where the FORTRAN code with program specifications are made available.

Wang, Hansheng; Wu, Patrick; Wang, Zhiyong

2006-12-01

123

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

124

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.

125

Spherical cap harmonic analysis of geomagnetic secular variation over Canada 1960-1983  

NASA Astrophysics Data System (ADS)

The new technique of spherical cap harmonic anaylsis has enabled a model of secular variation to be constructed that applies to an area of over 30 million square kilometers and a time interval of over 20 years. This technique is a regional analog of the ordinary method of spherical harmonic analysis and ensures that the curl and divergence of the secular variation vector are zero. By making each harmonic coefficient a polynomial in time, the model provides both spatial and temporal continuity. The secular variation data, from 1960 to 1983, comprise 1227 first central differences of annual mean values from 24 observatories in Canada, United States, Greenland, and Iceland, and 939 first central differences from 138 Canadian and American repeat stations, divided by their respective time intervals. The secular variation model includes terms up to spatial index 4 and temporal degree 2. Although such a model allows for 75 coefficients, only 39 were found to be statistically significant. The temporal behavior of the model at observatories and repeat stations is compared on time plots to that of the secular variation data itself. The scatter about the regression model, or standard error of estimate, was 11.8 nT/yr. The model is required both to update aeromagnetic survey data for producing Canadian geomagnetic main field charts at 1985.0 and to provide annual change information for the extrapolation of those charts up to 1990. The average secular variations derived from the Definitive (DGRF) and Provisional (PGRF) International Geomagnetic Reference Fields agree well with the model, but the average secular variation for 1980-1985 from the predictive International Geomagnetic Reference Field (IGRF) does not.

Haines, G. V.

1985-12-01

126

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

ERIC Educational Resources Information Center

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

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

2009-01-01

127

Explicit thermostatics of Stanley's n-vector model on the harmonic chain by Fourier analysis  

NASA Astrophysics Data System (ADS)

Thermostatic properties of Stanley's classical n-vector model on the harmonic chain are studied. It is shown that this model belongs to a rather general class of classical spin models in one dimension. The members of this class are characterized by spins which are elements of a homogenous space with transformation group G and a G-invariant and exchange-invariant spin-pair interaction. For the derivation of basic thermostatic quantities and correlation functions we use the method of abstract Fourier analysis. This allows to derive rather explicit results for any member of the aforementioned class of spin models. We present an exact closed-form expression as well as a high- and a low-temperature expansion for the free energy of Stanley'sn -vector model on the harmonic chain. From this basic thermostatic quantities like internal energy, entropy and heat capacity are obtained. Furthermore, we present results for expectation values of one-spin and two-spin functions. From the latter it is possible to derive the zero-field susceptibility and it also allows for a discussion of magnetostrictive effects.

Junker, Georg; Leschke, Hajo; Zan, Ingbert

1997-02-01

128

Autoregressive harmonic analysis of the earth's polar motion using homogeneous international latitude service data  

NASA Astrophysics Data System (ADS)

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. Principal conclusion of this analysis are that (1) 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, prograte motion, a behavior that is inconsistent with the hypothesis of a single Chandler period excited in a temporally and/or spatially random fashion). (2) the four-component Chandler wobble model ``explains'' the apparent phase reversal during 1920-1940 and the pre-1950 empirical period-amplitude relation, (3) 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. (4) the Markowitz wobble is found to support the large variations reported by earlier investigations. (4) 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.

Fong Chao, B.

1983-12-01

129

Third-order harmonic-expansion analysis of the Lorenz-Haken equations  

NASA Astrophysics Data System (ADS)

This paper aims at revisiting the basic Lorenz-Haken equations with two-fold harmonic-expansion approaches, yielding new analytical information on both the transient and the long term characteristics of the system pulse-structuring. First, we extend the well-known Casperson Hendow-Sargent weak-sideband analysis to derive a general formula that gives the value of the transient frequencies, characteristic of the laser relaxing towards its long-term state, either stable or unstable. Its validity is shown to apply with a remarkable precision at any level of excitation, both beyond and below the instability threshold. Second, we put forward a strong-harmonic expansion scheme to analyse the system long-term solutions. Carried up to third order in field amplitude, the method allows for the derivation of a closed form expression of the system eigen-frequency (derived here for the first time in three decades of laser dynamics) that naturally yields an iterative algorithm to build, analytically, the regular pulsing solutions of the Lorenz-Haken equations. These solutions are constructed for typical examples, extending well beyond the boundary region of the instability domain, inside which the laser field amplitude undergoes regular pulsations around zero-mean values.

Ayadi, S.; Meziane, B.

2008-05-01

130

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

SciTech Connect

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

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

2007-12-15

131

Tools for Physics Analysis in CMS  

NASA Astrophysics Data System (ADS)

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

Hinzmann, Andreas

2011-12-01

132

Fast and Accurate Generalized Harmonic Analysis and Its Parallel Computation by GPU  

NASA Astrophysics Data System (ADS)

A fast and accurate method for Generalized Harmonic Analysis is proposed. The proposed method estimates the parameters of a sinusoid and subtracts it from a target signal one by one. The frequency of the sinusoid is estimated around a peak of Fourier spectrum using binary search. The binary search can control the trade-off between the frequency accuracy and the computation time. The amplitude and the phase are estimated to minimize the squared sum of the residue after extraction of estimated sinusoids from the target signal. Sinusoid parameters are recalculated to reduce errors introduced by the peak detection using windowed Discrete-Time Fourier Transform. Audio signals are analyzed by the proposed method, which confirms the accuracy compared to existing methods. The proposed algorithm has high degree of concurrency and is suitable to be implemented on Graphical Processing Unit (GPU). The computational throughput can be made higher than the input audio signal rate.

Noda, Hisayori; Nishihara, Akinori

133

Analysis of spatial lamellar distribution from adaptive-optics second harmonic generation corneal images  

PubMed Central

The spatial organization of stromal collagen of ex-vivo corneas has been quantified in adaptive-optics second harmonic generation (SHG) images by means of an optimized Fourier transform (FT) based analysis. At a particular depth location, adjacent lamellae often present similar orientations and run parallel to the corneal surface. However this pattern might be combined with interweaved collagen bundles leading to crosshatched structures with different orientations. The procedure here reported provides us with both principal and crosshatched angles. This is also able to automatically distinguish a random distribution from a cross-shaped one, since it uses the ratio of the axes lengths of the best-fitted ellipse of the FT data as an auxiliary parameter. The technique has successfully been applied to SHG images of healthy corneas (both stroma and Bowman’s layer) of different species and to corneas undergoing cross-linking treatment.

Bueno, Juan M.; Palacios, Raquel; Chessey, Mary K.; Ginis, Harilaos

2013-01-01

134

Analysis of spatial lamellar distribution from adaptive-optics second harmonic generation corneal images.  

PubMed

The spatial organization of stromal collagen of ex-vivo corneas has been quantified in adaptive-optics second harmonic generation (SHG) images by means of an optimized Fourier transform (FT) based analysis. At a particular depth location, adjacent lamellae often present similar orientations and run parallel to the corneal surface. However this pattern might be combined with interweaved collagen bundles leading to crosshatched structures with different orientations. The procedure here reported provides us with both principal and crosshatched angles. This is also able to automatically distinguish a random distribution from a cross-shaped one, since it uses the ratio of the axes lengths of the best-fitted ellipse of the FT data as an auxiliary parameter. The technique has successfully been applied to SHG images of healthy corneas (both stroma and Bowman's layer) of different species and to corneas undergoing cross-linking treatment. PMID:23847727

Bueno, Juan M; Palacios, Raquel; Chessey, Mary K; Ginis, Harilaos

2013-06-04

135

Electromagnetic Interference Analysis Based on Total Harmonic Distortion Measurement in 900MHz Cordless Telephones  

NASA Astrophysics Data System (ADS)

In this paper a new electromagnetic (EM) interference analysis is proposed using the total harmonic distortion (THD) measurement of the audio signal by the 900MHz cordless telephones. The cordless telephone network in 900MHz was built up to be weak in EM interference. 400 and 800Hz of the sine-wave signal were used in transmitter (TX) system, and the receiver (RX) system was exposed to the EM interference. The THD value varies as the level of the exposed EM interference changes. The model of the cordless telephone also affects the THD value. By using fluctuation of the THD value depending on the amount of the exposure, the threshold value of the interference electric field strength was derived. Based on the derived threshold value of the electric field strength, validity of the regulation value for low power radio devices by CISPR 22 [CLASS B] and FCC is discussed.

Park, Jeung Geun; Kim, Che Young

136

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

Microsoft Academic Search

The multiple-slit type destructive interference in molecular high-order harmonic generation (HHG) leads to the minima in the harmonic yield for particular molecular orientation angle thetaL and the harmonic order n. For the case of homonuclear diatomic molecules, we have found a condition for this destructive interference in the form of a nonlinear equation over n and thetaL. This condition strongly

S. Odzak; D. B. Milosevic

2009-01-01

137

Commercial and Operational Analysis of a Passive Harmonic Filter (Indigenous Development)  

NASA Astrophysics Data System (ADS)

With the realization of power quality issues, the use of passive harmonic filters is increasing in all process industries day by day. Therefore it is necessary to find a balance between the commercial aspects and benefits of using harmonic filters. This paper is an effort to highlight the indigenous development of a passive third harmonic filter using a commercial product of ABB Pvt. Ltd. as a model by using reverse engineering technique.

Qureshi, Suhail Aftab; Sher, Hadeed Ahmed; Talib, Azeem; Ul Haque, Tanveer

2009-08-01

138

An Analysis of Shot Noise Propagation and Amplificationin Harmonic Cascade FELs  

SciTech Connect

The harmonic generation process in a harmonic cascade (HC) FEL is subject to noise degradation which is proportional to the square of the total harmonic order. In this paper, we study the shot noise evolution in the first-stage modulator and radiator of a HC FEL that produces the dominant noise contributions. We derive the effective input noise for a modulator operating in the low-gain regime, and analyze the radiator noise for a density-modulated beam. The significance of these noise sources in different harmonic cascade designs is also discussed.

Huang, Z.; /SLAC

2006-12-11

139

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

140

An induction motor speed measurement method based on current harmonic analysis with the chirp-Z transform  

Microsoft Academic Search

This paper presents a new method to measure motor speed by means of frequency estimation of rotor slot spectral components in the supply current of squirrel single-cage induction motors. The novelty of the method consists in the harmonic analysis of the supply current by means of the chirp-Z transform (CZT). The advantages are improved accuracy due to better spectral resolution

Massimo Aiello; Antonio Cataliotti; Salvatore Nuccio

2005-01-01

141

Column and row operator spaces over QSL_p-spaces and their use in abstract harmonic analysis  

Microsoft Academic Search

The notions of column and row operator space were extended by A. Lambert from Hilbert spaces to general Banach spaces. In this paper, we use column and row spaces over quotients of subspaces of general $L_p$-spaces to equip several Banach algebras occurring naturally in abstract harmonic analysis with canonical, yet not obvious operator space structures that turn them into completely

Matthias Neufang; Volker Runde

2007-01-01

142

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

Microsoft Academic Search

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

A. Gover; A. Friedman; A. Luccio

1987-01-01

143

Method of analyzing multiparameter information during the harmonic analysis of the emf of an eddy-current sensor \\/transducer  

Microsoft Academic Search

Arrangements for 'tuning out' interfering factors in the analysis of multidimensional information, expressed as a spectrum comprising the higher harmonics of the secondary emf in an eddy-current sensor (transducer), are described. The possibility of increasing accuracy in the estimation of any desired parameter is established. The necessary conditions for determining the suitability of the detuning channel and for solving systems

Iu. I. Lugovets; G. M. Kurakin

1975-01-01

144

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

145

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

146

High-order harmonic generation in diatomic molecules: A quantum-orbit analysis of the interference patterns  

SciTech Connect

We perform a detailed analysis of high-order harmonic generation in diatomic molecules within the strong-field approximation (SFA), with emphasis on quantum-interference effects. Specifically, we investigate how the different types of electron orbits, involving one or two centers, affect the interference patterns in the spectra. We also briefly address the influence of the choice of gauge and of the initial and final electronic bound states on such patterns. For the length-gauge SFA and undressed bound states, there exist additional terms, which can be interpreted as potential energy shifts. If, on the one hand, such shifts alter the potential barriers through which the electron initially tunnels, and may lead to a questionable physical interpretation of the features encountered, on the other hand, they seem to be necessary in order to reproduce the overall maxima and minima in the spectra. Indeed, for dressed electronic bound states in the length gauge, or undressed bound states in the velocity gauge, for which such shifts are absent, there is a breakdown of the interference patterns. In order to avoid such a problem, we provide an alternative pathway for the electron to reach the continuum, by means of an additional attosecond-pulse train. A comparison of the purely monochromatic case with the situation for which the attosecond pulses are present suggests that the patterns are due to the interference between the electron orbits which finish at different centers, regardless of whether one or two centers are involved.

Figueira de Morisson Faria, C. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2007-10-15

147

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

Microsoft Academic Search

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

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

2006-01-01

148

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

PubMed

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

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

149

Theoretical analysis of high-order harmonic generation from a coherent superposition of states  

SciTech Connect

A quantum theory of high-order harmonic generation by a strong laser field in the presence of more bound states is formulated. The obtained numerical and analytical results for a two-state hydrogenlike atom model show that the harmonic spectrum consists of two parts: a usual single-state harmonic spectrum of odd harmonics having the energies (2k+1){omega} and a resonant part with the peaks around the excitation energy {delta}{omega}. The energy of the harmonics in the resonant part of the spectrum is equal to {delta}{omega}{+-}{omega}, {delta}{omega}{+-}3{omega}, .... For energies higher than the excitation energy, the resonant part forms a plateau, followed by a cutoff. The emission rate of the harmonics in this resonant plateau is many orders of magnitude higher than that of the harmonics generated in the presence of the ground state alone. The influence of the depletion of the initial states, as well as of the pulse shape and intensity, is analyzed.

Milosevic, Dejan B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, Berlin, 12489 (Germany)

2006-02-15

150

Bifurcation analysis of a non-linear hysteretic oscillator under harmonic excitation  

NASA Astrophysics Data System (ADS)

The steady state oscillations of a system incorporating a non-linear hysteretic damper are studied analytically by applying a perturbation technique. The hysteretic damper of the system subject to harmonic resonant force is modelled by combining a Maxwell's model and Kelvin-Voigt's model in series. The non-linearity is imposed by replacing a spring element by a cubic-non-linear spring. The response of the system is described by two coupled second order differential equations including a non-linear constitutive equation. Proper rescaling of the variables and parameters of the equations of motion leads to a set of weakly non-linear equations of motion to which the method of averaging is applied. The bifurcation analysis of the reduced four-dimensional amplitude- and phase-equations of motion shows typical non-linear behaviors including saddle-node and Hopf bifurcations and separate solution branch. By the stability analysis, the saddle-node and Hopf bifurcation sets are obtained in parameter spaces. The software package AUTO is used to numerically study the bifurcation sets and limit cycle solutions bifurcating from the Hopf bifurcation points. It is shown that the limit cycle responses of the averaged system exist over broad parameter ranges.

Il Chang, Seo

2004-09-01

151

Comparisons between harmonic balance and nonlinear output frequency response function in nonlinear system analysis  

NASA Astrophysics Data System (ADS)

By using the Duffing oscillator as a case study, this paper shows that the harmonic components in the nonlinear system response to a sinusoidal input calculated using the nonlinear output frequency response functions (NOFRFs) are one of the solutions obtained using the harmonic balance method (HBM). A comparison of the performances of the two methods shows that the HBM can capture the well-known jump phenomenon, but is restricted by computational limits for some strongly nonlinear systems and can fail to provide accurate predictions for some harmonic components. Although the NOFRFs cannot capture the jump phenomenon, the method has few computational restrictions. For the nonlinear damping systems, the NOFRFs can give better predictions for all the harmonic components in the system response than the HBM even when the damping system is strongly nonlinear.

Peng, Z. K.; Lang, Z. Q.; Billings, S. A.; Tomlinson, G. R.

2008-03-01

152

Regulatory Harmonization  

Center for Biologics Evaluation and Research (CBER)

. The Agency engages in a range of explicit harmonization initiatives, a subset of which includes the participation of CBER. ... More results from www.fda.gov/biologicsbloodvaccines/internationalactivities

153

Physics analysis tools for beauty physics in ATLAS  

Microsoft Academic Search

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.

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

2008-01-01

154

Harmonic analysis of environmental time series with missing data or irregular sample spacing.  

PubMed

The Lomb periodogram and discrete Fourier transform are described and applied to harmonic analysis of two typical data sets, one air quality time series and one water quality time series. The air quality data is a 13 year series of 24 hour average particulate elemental carbon data from the IMPROVE station in Washington, D.C. The water quality data are from the stormwater monitoring network in Milwaukee, WI and cover almost 2 years of precipitation events. These data have irregular sampling periods and missing data that preclude the straightforward application of the fast Fourier transform (FFT). In both cases, an anthropogenic periodicity is identified; a 7-day weekday/ weekend effect in the Washington elemental carbon series and a 1 month cycle in several constituents of stormwater. Practical aspects of application of the Lomb periodogram are discussed, particularly quantifying the effects of random noise. The proper application of the FFT to data that are irregularly spaced with missing values is demonstrated on the air quality data. Recommendations are given when to use the Lomb periodogram and when to use the FFT. PMID:17993144

Dilmaghani, Shabnam; Henry, Isaac C; Soonthornnonda, Puripus; Christensen, Erik R; Henry, Ronald C

2007-10-15

155

Geomagnetic secular variation over Spain 1970-1988 by means of spherical cap harmonic analysis  

NASA Astrophysics Data System (ADS)

A spherical cap harmonic analysis was applied to Spain and neighbouring areas, covering a region with a cap halfangle of 16°. The technique, due to Haines, has allowed us to obtain a model of secular variation (SV) for a time interval of 18 years reduced to the epoch 1987.5. The total number of selected data points was 1581 provided from ten observatories and 60 repeat stations. The SV model has a maximum spatial index of four and temporal degree of two. The coefficients were tested and the statistically non-significant terms removed. Another model covering a smaller region with greater density of data has been developed and both results compared. The average secular variations derived from the definitive geomagnetic reference field (DGRF) and the international geomagnetic reference field (IGRF) were compared with these models and maps plotting the calculated first field derivatives are presented. The integration of the final model will serve to update satellite data in order to produce a regional main field model.

Garcia, A.; Torta, J. M.; Curto, J. J.; Sanclement, E.

1991-08-01

156

Data Analysis for Physical Scientists  

NASA Astrophysics Data System (ADS)

1. Introduction to scientific data analysis; 2. Excel and data analysis; 3. Data distributions I; 4. Data distributions II; 5. Measurement, error and uncertainty; 6. Least squares I; 7. Least squares II; 8. Non-linear least squares; 9. Tests of significance; 10. Data analysis tools in Excel and the Analysis ToolPak; Appendixes; Answers to exercises and end-of-chapter problems; References; Index.

Kirkup, Les

2012-02-01

157

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

PubMed Central

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

2011-01-01

158

A development environment for visual physics analysis  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

159

Harmonic detection by using neural network  

Microsoft Academic Search

A methodology of harmonic detection in active power filter from the power line by using neural network is presented. Harmonic detection by using Fourier transformation is an advantageous method to compensate a specific harmonic component. However, it needs input data for each cycle of the current waveform and needs time for the analysis in each cycle. Therefore, the harmonic compensation

N. Pecharanin; H. Mitsui; M. Sone

1995-01-01

160

[Third harmonic enhancement and spectral analysis within plasma channel based on pump-probe effect].  

PubMed

The experiment realized third harmonic enhancement by using non-collinear dual plasma channels based on pump-probe effect. The coupling action between pump and probe beams can improve saturation effect within filament and overcome the limitation of harmonic enhancement due to intensity clamping. By non-collinearly focusing two ultrafast pulses in air which have respectively a single pulse energy of 4.4 and 10.2 mJ, both with duration of 60 fs and central wavelength of 810 nm, dual filaments as well as weak third harmonics can be generated. When strong beam is ahead of weak one, the former induces a plasma channel in advance which can modulate later weak beam and make obvious harmonic increase produced by probe beam. It was found that oscillation variation of spectral bandwidth in the region of harmonic energy increased significantly. When two beams intersect in a small angle of 27.3 mrad about 15 mm before geometric focus and the probe beam lags behind about 55 fs, the energy increase rate nearly reaches 70, and the corresponding spectral bandwidth is approximately 5 nm. PMID:20827961

Wang, Yan-ling; Wu, Hong; Ding, Liang-en

2010-07-01

161

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

162

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

SciTech Connect

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

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

2010-04-15

163

Structural analysis of blended materials using multiphoton autofluorescence and second harmonic generation microscopy  

NASA Astrophysics Data System (ADS)

The purpose of this work is to investigate the microstructure of blended materials using non-invasive, optical imaging modality. Multiphoton autofluorescence and second harmonic generation signals will be used for characterizing and quantifying individual non-linear optical properties of each polymer in pure polymeric thin films. In addition, reflected confocal signals will used to outline the interface of refractive index mismatch. And the phase separation phenomenon of immiscible blended membranes composed of different ratio of nylon and chitosan are analyzed and differentiated using the non-invasive optical information including autofluerescence, second harmonic generation, and reflected signals. We therefore propose the potentiality of using multiphoton autofluorescence and second harmonic generation microscopy complemented with reflected confocal microscopy for studying the synthetic blended polymeric scaffolds and also, in the future, the dynamic, in vivo, cell-matrix interaction in the field of tissue engineering.

Tan, Hsin-Yuan; Lin, Ming-Guo; Lin, Sung-Jan; Hsiao, Wen-Chu; Wen, Liang-Kung; Chen, Wei-Liang; Young, Tai-Horng; Dong, Chen-Yuan

2007-03-01

164

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

NASA Astrophysics Data System (ADS)

We present a generic approach for treating the effect of nuclear motion in high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors, which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH4 and CD4 and thereby provide direct theoretical support for a recent experiment [S. Baker , Science 312, 424 (2006)] that uses high-order harmonic generation to probe the ultrafast structural nuclear rearrangement of ionized methane.

Madsen, C. B.; Abu-Samha, M.; Madsen, L. B.

2010-04-01

165

Finite Element Three-Dimensional Nonlinear Transient Analysis of the Shaded Pole Motor with Emphasis on Harmonics Analysis  

Microsoft Academic Search

A finite element method is used to analyze the characteristics and performance of a shaded pole motor. The importance of the spacial harmonics are investigated by finding the trajectory (locus) of spacial harmonics in the air-gap. The possibility of developing a reliable method for analyzing the shaded pole motor is investigated by attempt to express the nonuniform rotating field in

Hamid Reza Sadeghi

1994-01-01

166

Numerical analysis of near and far field patterns of second-harmonic generation with tiling nonlinear optical crystals  

NASA Astrophysics Data System (ADS)

We report numerical analysis of near- and far-field patterns of the second-harmonic wave in a large-scale high-power laser used in the laser fusion with type I KDP crystals arranged in a tiling style. The thickness and phase-matching angle of the tiling crystals are designed based on the near-field pattern of the second-harmonic wave. The tilting angle error and thickness difference of the tiling crystals are evaluated by the energy distribution included in the Airy spot of the far-field pattern at the focal point. The parallelism and flatness of the tiling crystals can also be estimated with the same method.

Harimoto, T.; Shiraga, H.

2008-05-01

167

Structural analysis of blended materials using multiphoton autofluorescence and second harmonic generation microscopy  

Microsoft Academic Search

The purpose of this work is to investigate the microstructure of blended materials using non-invasive, optical imaging modality. Multiphoton autofluorescence and second harmonic generation signals will be used for characterizing and quantifying individual non-linear optical properties of each polymer in pure polymeric thin films. In addition, reflected confocal signals will used to outline the interface of refractive index mismatch. And

Hsin-Yuan Tan; Ming-Guo Lin; Sung-Jan Lin; Wen-Chu Hsiao; Liang-Kung Wen; Wei-Liang Chen; Tai-Horng Young; Chen-Yuan Dong

2007-01-01

168

Analysis and Reduction of Time Harmonic Rotor Loss in Solid-Rotor Synchronous Reluctance Drive  

Microsoft Academic Search

Synchronous reluctance machines with solid rotor construction have advantages in certain high-speed applications such as flywheel energy storage systems. However, the solid rotor allows the flow of eddy currents, resulting in rotor loss and heat generation. The switching harmonics in the stator voltage supplied by a pulsewidth modulation (PWM) inverter are one of the sources of the rotor loss. This

Jae-Do Park; Claude Kalev; Heath F. Hofmann

2008-01-01

169

Global analysis of an harmonically excited spring-pendulum system with internal resonance  

Microsoft Academic Search

A non-linear system can often have multiple attractors. In this case, it is important to study the global behavior of the system by determining the global domain of attraction of each attractor. This paper is concerned with the global behavior of an harmonically excited spring-pendulum system with internal resonance. Before studying the global behavior, the local behaviors of the system

W. K. Lee; C. S. Hsu

1994-01-01

170

Inexact-Newton Harmonic-Balance Analysis with Time-Dependent Phasors  

Microsoft Academic Search

The simulation of nonlinear RF\\/microwave circuits driven by modulated carriers is tackled by a novel harmonic-balance (HB) technique. The electrical regime is described as a sequence of RF steady states slowly changing with time at the rate of the baseband modulating signals. Each RF state is coupled to a small number of neighboring sampling instants, and the nonlinear HB system

Vittorio Rizzoli; Andrea Neri; Franco Mastri; Alessandro Lipparini

1998-01-01

171

An Analysis of the Impact of the Harmonized Sales Tax on Provincial Revenues in Atlantic Canada  

Microsoft Academic Search

This paper examines the impact of the harmonized sales tax (HST) on the provincial consumption tax revenues of the three participating Atlantic Canadian provinces over the period 1997 to 2003. Relative to forecasts that I construct, I find that this category of provincial revenue has fallen substantially in Newfoundland and Labrador and New Brunswick as a direct result of the

Patrick Blagrave

2005-01-01

172

Susceptibility analysis of a nonlinear system using hybrid method of Electromagnetic Topology and Harmonic Balance  

Microsoft Academic Search

This paper suggests an improved Electromagnetic Topology (EMT) method, based on Harmonic Balance (HB), to analyze electromagnetic field coupling to nonlinear system. In the proposed method, EMT and HB communicate in real-time. The voltage results from the HB are imposed on the EMT as boundary conditions and the voltage results from EMT are used for computing linear and nonlinear currents

Yoon-Mi Park; Min-Hyuk Kim; Changyul Cheon; Hyun-Kyo Jung; Young-Seek Chung

2010-01-01

173

Modal analysis using the Bessel harmonics of an extrinsic Fabry-Perot interferometric sensor (EFPI) and neural networks  

NASA Astrophysics Data System (ADS)

A demodulation system employing neural networks is used to process the non-linear signal from an extrinsic Fabry-Perot interferometric (EFPI) sensor. A sinusoidal strain is theoretically shown to produce well-defined Bessel harmonics in the EFPI signal. The neural network demodulator (NND) uses a Fourier Series Neural Network to separate the Bessel harmonic components of the EFPI signal and a Back-Propagation Neural Network is used to predict the strain levels through the analysis of the Bessel harmonics. The NND is first simulated in a computer program and then actually employed in an experimental setting to determine the frequency response of a 25 cm composite cantilever beam. A function generator was used to drive a PZT actuator attached to the composite beam and resulting periodic strain was measured by the EFPI; the frequency of the composite beam was varied between 10 Hz and 900 Hz. The NND demodulated the EFPI signal and determined the frequency response of the composite beam. The results show that the NND accurately reproduced the natural frequencies and mode shapes of the cantilever beam.

Abdi, Abdeq M.; Watkins, Steve E.

2006-04-01

174

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

SciTech Connect

The merits of the new slip-energy recovery drive system that has been proposed in Part 1 of this paper is demonstrated here. Experimental work is carried out to verify the simulated models of the proposed and conventional systems. Furthermore, harmonic analysis of both systems is conducted analytically and confirmed numerically using the FFT. The main feature of the new proposed system is the significant reduction in the harmonics of the rotor flux linkage. This leads to substantial reductions in the stator current harmonics. Moreover, the pulsating components in the developed electromagnetic torque are also reduced significantly in the new proposed system.

Zakaria, W.S. [United Arab Emirates Univ., El-Ain (United Arab Emirates); Shaltout, A.A. [Cairo Univ. (Egypt); Alwash, S.R. [Jordan Univ. of Science and Technology, Irbid (Jordan)

1996-09-01

175

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

176

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

177

A Time-Distinguished Analysis of the Harmonic Structure from a Model Molecular Ion  

NASA Astrophysics Data System (ADS)

We present high-order harmonic generation spectra resulted from a single-electron model molecular ion exposed to intense laser fields by numerically solving a one-dimensional time-dependent Schrödinger equation. There are three plateaus in the spectra and the maximal cutoff energy is Ip+8.5Up, when the inter-nuclear distance R equals pialpha0/2. Here Ip is the ionization potential and Up = E02/(4omega2) is the ponderomotive potential with E0 and omega being the laser electric field amplitude and the central frequency. The harmonic structures are well interpreted by a modified three-step model in which the effects of the electron reflected by the non-parent ion are stressed.

Yang, Yu-Jun; Chen, Gao; Chen, Ji-Gen; Zhu, Qi-Ren

2004-04-01

178

Analysis and simulation of five-phase synchronous reluctance machines including third harmonic of airgap MMF  

Microsoft Academic Search

In this paper, the winding function method in conjunction with the coupled magnetic circuit approach are used to develop the dynamic equations of a five-phase synchronous reluctance machine in the natural frame of reference (a-b-c-d-e). The effect of the third harmonic of the airgap MMF is included in this development. A five-phase transformation from the (a-b-c-d-e) system to a (d1-q1-d3

Hamid A. Toliyat; Shailesh P. Waikar; Thomas A. Lipo

1998-01-01

179

An electron-hole transport model for the analysis of the photorefractive harmonic gratings  

Microsoft Academic Search

The steady-state exact solution for the higher har- monic gratings that synthesize the space-charge field is derived without restrictions within an electron-hole transport model which allows the behavior of these harmonic gratings to be determined rigorously in terms of the main photorefractive parameters. The model predicts the independence of the fundamental and har- monic amplitudes on the average excitation intensity.

P. Vaveliuk; B. Ruiz; O. M. Matos; G. A. Torchia; N. Bolognini

2001-01-01

180

Preliminary analysis of MV cable line models for high frequency harmonic penetration studies  

Microsoft Academic Search

The large penetration of distributed generation requires accurate line and cable models in a frequency range much wider than the classical interval, 0-2.5 kHz, used for traditional harmonic and interharmonic penetration studies. In the paper, the behavior of MV cable lines is considered in the frequency range from 0 to 100 kHz, with reference to a casestudy. Models base on

R. Langella; L. Nunges; F. Pilo; G. Petretto; S. Scalari; A. Testa

2011-01-01

181

Spectral analysis of high-harmonic coherent acoustic phonons in piezoelectric semiconductor multiple quantum wells  

Microsoft Academic Search

Multiple harmonic components have been observed in the Fourier spectra of the coherent acoustic phonon oscillations in InGaN\\/GaN multiple quantum wells (MQW's). The dependence of the relative magnitudes of the first two Fourier components on the sample geometry was analyzed by conducting time-resolved pump-probe measurements on MQW samples with different well-to-barrier ratios. The results were also compared with the recently

Gia-Wei Chern; Kung-Hsuan Lin; Yue-Kai Huang; Chi-Kuang Sun

2003-01-01

182

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

NASA Astrophysics Data System (ADS)

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

Romijn, Elisabeth I.; Lilledahl, Magnus B.

2013-02-01

183

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

USGS Publications Warehouse

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

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

1985-01-01

184

Analysis of harmonic and transient phenomena due to operation of a-c arc furnace  

SciTech Connect

Operation of an a-c electric arc furnace load is associated with the generation of harmonic currents in the frequency range of fractions of Hertz up to approximately 1,000 Hz. The magnitude of these harmonic current components can be high and depends on the diverse operating condition of the system. Exposure of the furnace yard electrical components to overvoltages and overcurrents as a result of current harmonics, produces high electrical and mechanical stresses in the components which, if not accounted for in design, may result in failures. Operating experience with existing electric furnace installations indicates an uncharacteristically high failure rate of components which impose long time system outages and, thereby, reduce product output. A statistical 3-phase model for an arc furnace load in EMTP for time domain simulation studies will be presented. The model is first validated against field measurements and then used to examine the effect of the insertion of series reactors at the supply side of the furnace transformer on the dynamic inrush current associated with furnace transformer switching. It is shown that the insertion of a series reactor will considerably reduce the impact of furnace transformer dynamic inrush current on the filter components. The model is also used to evaluate the actual required design to withstand capabilities of the filter components. Some of the shortcomings of the conventional specifications are illustrated.

Sarshar, A.; Sharp, M. [Haefely-Trench High Voltage Technology, Scarborough, Ontario (Canada); Iravani, R.M. [Univ. of Toronto, Ontario (Canada). Dept. of Electrical and Computing Engineering

1995-07-01

185

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

186

A Theoretical Analysis of Sideband Harmonics on the Inverter DC-link Current for an Electric Railcar  

NASA Astrophysics Data System (ADS)

The harmonics of the return current may interfere with the signaling current along with the rails. In this paper, we present the theoretical studies of the return current harmonics in the inverter-controlled DC electric railcar, aiming at contributing future work to improve the compatibility with the signaling current. We theoretically derive sideband harmonics of the DC-link current. Then, in order to verify the theoretical study, we experimentally measure the harmonics and numerically simulate the harmonics. As a result, we concluded the theoretical DC-link current is enough accurate to be utilized for the future improvement of the inverter harmonics current.

Ogawa, Tomoyuki; Wakao, Shinji; Taufiq, Jat; Kondo, Keiichiro; Terauchi, Nobuo

187

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

188

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

189

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

190

Time-Symmetric Discretization of The Harmonic Oscillator  

SciTech Connect

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

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

2010-11-24

191

A Theoretical Analysis of Sideband Harmonics on the Inverter DC-link Current for an Electric Railcar  

Microsoft Academic Search

The harmonics of the return current may interfere with the signaling current along with the rails. In this paper, we present the theoretical studies of the return current harmonics in the inverter-controlled DC electric railcar, aiming at contributing future work to improve the compatibility with the signaling current. We theoretically derive sideband harmonics of the DC-link current. Then, in order

Tomoyuki Ogawa; Shinji Wakao; Jat Taufiq; Keiichiro Kondo; Nobuo Terauchi

2006-01-01

192

A more accurate analysis of Bose-Einstein condensation in harmonic traps  

NASA Astrophysics Data System (ADS)

Using the Euler-Maclaurin summation we calculate analytically the internal energy for non-interacting bosons confined within a harmonic oscillator potential. The specific heat shows a sharp ?-like peak indicating a condensation into the ground state at a well-defined transition temperature. Full agreement is obtained with direct numerical calculation of the same quantities. When the number of trapped particles is very large and at temperatures near and above the transition temperature, the results also agree with previous approximate calculations. At extremely low temperatures both the specific heat and the number of particles excited from the condensate are exponentially suppressed.

Haugerud, H.; Haugset, T.; Ravndal, F.

1997-02-01

193

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

194

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

NASA Astrophysics Data System (ADS)

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.

1983-12-01

195

The Green's matrix and the boundary integral equations for analysis of time-harmonic dynamics of elastic helical springs.  

PubMed

Helical springs serve as vibration isolators in virtually any suspension system. Various exact and approximate methods may be employed to determine the eigenfrequencies of vibrations of these structural elements and their dynamic transfer functions. The method of boundary integral equations is a meaningful alternative to obtain exact solutions of problems of the time-harmonic dynamics of elastic springs in the framework of Bernoulli-Euler beam theory. In this paper, the derivations of the Green's matrix, of the Somigliana's identities, and of the boundary integral equations are presented. The vibrational power transmission in an infinitely long spring is analyzed by means of the Green's matrix. The eigenfrequencies and the dynamic transfer functions are found by solving the boundary integral equations. In the course of analysis, the essential features and advantages of the method of boundary integral equations are highlighted. The reported analytical results may be used to study the time-harmonic motion in any wave guide governed by a system of linear differential equations in a single spatial coordinate along its axis. PMID:21428495

Sorokin, Sergey V

2011-03-01

196

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

197

Harmonic engine  

DOEpatents

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

Bennett, Charles L. (Livermore, CA)

2009-10-20

198

Demonstration and analysis of the harmonic dithering technique for a high-sensitivity silicon waveguide biosensor  

NASA Astrophysics Data System (ADS)

A label-free biosensor readout technique is demonstrated based on a silicon-on-insulator ring resonators and a harmonic dithering technique using a distributed feedback (DFB) laser and a lock-in amplifier. The 400 ?m ring resonator is integrated with a microfluidic sample delivery channel formed with Polydimethylsiloxane (PDMS). Dithering the frequency of the DFB laser across the Lorentzian lineshape of the drop port at high frequency eliminates 1/f noise, and broadband noise is reduced by narrow-band detection with the lock-in amplifier. Biosensor system noise is analyzed and compared with more conventional readout methods, and in our case is dominated by thermal noise of the receiver, shot noise, and relative intensity noise (RIN) of the DFB laser. Because the readout automatically latches onto the drop port and does not require a complex scanning process, this methodology may provide a pathway for high-sensitivity, real-time, and low-cost biosensing.

Kim, Kangbaek; Pafcheck, Robert M.; Koch, Thomas L.

2012-02-01

199

Spectral analysis of high-harmonic coherent acoustic phonons in piezoelectric semiconductor multiple quantum wells  

NASA Astrophysics Data System (ADS)

Multiple harmonic components have been observed in the Fourier spectra of the coherent acoustic phonon oscillations in InGaN/GaN multiple quantum wells (MQW’s). The dependence of the relative magnitudes of the first two Fourier components on the sample geometry was analyzed by conducting time-resolved pump-probe measurements on MQW samples with different well-to-barrier ratios. The results were also compared with the recently proposed loaded-string model [Phys. Rev. B 64, 235316 (2001)], and an overall agreement is obtained which validates the picture of string oscillation with inhomogeneous loadings. We also demonstrated manipulation of the spectral components using the coherent optical control technique. Our demonstration can be regarded as a first step to the realization of wave-form synthesis of nanoacoustic waves.

Chern, Gia-Wei; Lin, Kung-Hsuan; Huang, Yue-Kai; Sun, Chi-Kuang

2003-03-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

201

Gender and Physics: a Theoretical Analysis  

NASA Astrophysics Data System (ADS)

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

Rolin, Kristina

202

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

PubMed Central

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

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

2012-01-01

203

Harmonic Filter Analysis and Redesign for a Modern Steel Facility with Two Melt Furnaces Using Dedicated Capacitor Banks  

Microsoft Academic Search

This modern steel making facility relies on reactive compensation at the substation level in the form of harmonic filtering to support voltage for casting operations, and at the melt furnace level in the form of capacitor banks to support LMF operations. A history of harmonic filter failures at the substation, and intermittent capacitor unit failures at the melt furnace banks,

T. J. Dionise; V. Lorch

2006-01-01

204

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

205

Study of saturation effects in brushless DC spindle motors using harmonics analysis method  

Microsoft Academic Search

In analysis of brushless dc (BLDC) motors, the effect of saturation needs to be appropriately considered especially in the case of small disk format where the housing space is very limited for the spindle. In this paper, we propose a practical method for analysis of saturation effects in BLDC spindle motors. The model is based on the comparative analysis of

J. T. Li; Z. J. Liu; C. Bi

2010-01-01

206

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

207

Covariant Harmonic Oscillators and Coupled Harmonic Oscillators.  

National Technical Information Service (NTIS)

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 ...

D. Han Y. S. Kim M. E. Noz

1995-01-01

208

Self-consistent harmonic generation in storage ring FELs  

NASA Astrophysics Data System (ADS)

We explore the self-induced harmonic generation in Storage Ring Optical Klystron (SR OK) FEL devices. We use a numerical code which accounts for the SR OK FEL longitudinal dynamics, includes the laser pulse propagation, and gives an accurate image of the phenomenology of instabilities associated with the laser-electron beam interplay. The coherent harmonic generation evolution is developed using the bunching parameter theory. The analysis we develop yields the turn-by-turn evolution of the harmonics and provides an accurate physical insight into their dependence on the intracavity laser power. The results obtained with this code are considered with mainly a Q-switched configuration evaluated for an Elettra-like facility.

Rippon, C.; Bartolini, R.; Dattoli, G.; Giannessi, L.; Couprie, M. E.; Garzella, D.

2003-07-01

209

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

Code of Federal Regulations, 2010 CFR

...false PAE Physical Condition Analysis (PCA). 401.451 Section 401.451 Housing...451 PAE Physical Condition Analysis (PCA). (a) Review and certification of...physical condition of the project by means of a PCA. If the PAE finds any immediate...

2009-04-01

210

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

Code of Federal Regulations, 2010 CFR

...false PAE Physical Condition Analysis (PCA). 401.451 Section 401.451 Housing...451 PAE Physical Condition Analysis (PCA). (a) Review and certification of...physical condition of the project by means of a PCA. If the PAE finds any immediate...

2010-04-01

211

The Not-So-Simple Harmonic Oscillator  

Microsoft Academic Search

The study of simple harmonic oscillators is a staple of physics courses and laboratories at the introductory level. We consider a system consisting of a vertical spring with a suspended mass. One typical laboratory experiment is the demonstration of Hooke's law using static measurements of extension vs. force. Another is the demonstration of simple harmonic motion using dynamic measurements of

William Sears; G. Whitmore Hancock

2007-01-01

212

Investigation of the nonlinear circuit analysis by electromagnetic topology based on harmonic balance  

Microsoft Academic Search

In this paper, a new EMT method based on HB for a nonlinear system is proposed. The EMT method has been restricted to linear analysis; however nonlinear circuit analysis is possible by the EMT-HB method. To reveal nonlinear characteristics by the HB in the EMT, the updated voltage results of the HB are applied to the EMT as sources. And

Yoon-Mi Park; Min-Hyuk Kim; Changyul Cheon; Hyun-Kyo Jung; Young-Seek Chung

2010-01-01

213

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

SciTech Connect

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

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

2009-07-07

214

Physical Readiness Training: A Meta-Analysis.  

National Technical Information Service (NTIS)

Distributed operations accentuate the need for physical fitness in military personnel. Traditional training practices may not be aligned with the fitness requirements of DO combat. Physical readiness training (PRT) is a conceptual approach to address this...

J. R. Vickers

2007-01-01

215

High-order harmonic generation from two-center molecules: Time-profile analysis of nuclear contributions  

SciTech Connect

We solve the exact three-dimensional time-dependent Schroedinger equation for H{sub 2}{sup +} (with fixed nuclei) interacting with an intense laser pulse with an arbitrary oriented linear polarization. We find that at equilibrium internuclear distance, the ionization probability of H{sub 2}{sup +} is maximum for the parallel orientation of the molecule with respect to the laser polarization, and is minimum for the perpendicular orientation. The contribution of each nucleus to the harmonic spectrum is evaluated, so that interference effects between the two contributions are assessed unambiguously. We show that every half-cycle, high order harmonics are emitted by each nucleus when the electron wave packet returns for a recollision with both nuclei, and that the resulting harmonic emission is predominant for the nucleus that experiences the first recollision. In general, each nucleus emits both even and odd harmonics, but even harmonics are destroyed by interferences between contributions from each nucleus. In general, this destructive interference occurs over a large spread of harmonic orders, which depends on the angle between the molecular axis and the laser polarization.

Kamta, G. Lagmago; Bandrauk, A.D. [Laboratoire de Chimie Theorique, Faculte des Sciences, Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada)

2004-07-01

216

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

SciTech Connect

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

Modi, Mohammed H.; Gupta, R. K.; Lodha, G. S. [X-ray Optics Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

2012-06-05

217

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

218

Forensic physical memory analysis: an overview of tools and techniques  

Microsoft Academic Search

Forensic physical memory analysis has gradually evolved from basic techniques such as string searching to more com- plex methods. As computer malware becomes more sophis- ticated, tools and techniques for memory analysis suffer in- adequacies. Given this, it is essential to examine tools and techniques for physical memory analysis. By understanding their behaviour, limitations and advantages it is possible then

Gabriela Limon Garcia

219

Cost and performance analysis of physical security systems  

Microsoft Academic Search

Analysis of cost and performance of physical security systems can be a complex, multi-dimensional problem. There are a number of point tools that address various aspects of cost and performance analysis. Increased interest in cost tradeoffs of physical security alternatives has motivated development of an architecture called Cost and Performance Analysis (CPA), which takes a top-down approach to aligning cost

M. J. Hicks; D. Yates; W. H. Jago; A. W. Phillips

1998-01-01

220

Modified ERA method for operational modal analysis in the presence of harmonic excitations  

Microsoft Academic Search

Operational modal analysis (OMA) is a procedure which allows to extract modal parameters of structures from measured responses to unknown excitation arising in operation. It is based on the assumption that the input to the structure is stationary white noise. In practice, however, structural vibration observed in operation cannot always be considered as pure white-noise excitation. In many practical cases,

Prasenjit Mohanty; Daniel J. Rixen

2006-01-01

221

Fourier transform, wavelets, Prony analysis: tools for harmonics and quality of power  

Microsoft Academic Search

The Fourier transform is a very useful tool for signal studies. Nevertheless there are many problems in using it; but these problems are very well known and correctly explained in literature. Wavelets are not usual in power network analysis. However, they are easy to use and give good results; the edge effects are transient and the computation time may be

M. Meunier; F. Brouaye

1998-01-01

222

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

223

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

224

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

225

Design of dispersion section for the ATF harmonic generation FEL  

SciTech Connect

We present an analysis of the dispersion magnet for the high gain harmonic generation experiment to be carried out at the Accelerator Test Facility at BNL. The purpose of the dispersion magnet is to convert energy modulation of the electron beam into spatial bunching. For the dispersion magnet, we discuss the physical requirements, analyze the magnetic design, determine the focusing properties, and consider the effect on the FEL gain of departures from idea behavior on the FEL gain.

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

1992-10-01

226

Design of dispersion section for the ATF harmonic generation FEL  

SciTech Connect

We present an analysis of the dispersion magnet for the high gain harmonic generation experiment to be carried out at the Accelerator Test Facility at BNL. The purpose of the dispersion magnet is to convert energy modulation of the electron beam into spatial bunching. For the dispersion magnet, we discuss the physical requirements, analyze the magnetic design, determine the focusing properties, and consider the effect on the FEL gain of departures from idea behavior on the FEL gain.

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

1992-01-01

227

Analysis of a harmonic overvoltage due to transformer saturation following load shedding on Hydro-Quebec - NYPA 765 kV interconnection  

SciTech Connect

This paper presents an analysis of the harmonic overvoltage recorded on the interconnection between Hydro-Quebec and the New York Power Authority (NYPA) in the Chateauguay area. The overvoltage was caused by transformer saturation, following tripping of the 765-kV transmission line linking both systems. The EMTP simulation yielded good agreement with field measurements and was valuable in re-evaluating operating practices at the Chateauguay station.

Bourgault, O.; Morin, G. (Hydro-Quebec, Montreal (CA))

1990-01-01

228

An analysis of the short-characteristic method for the spherical harmonic discrete ordinate method (SHDOM)  

NASA Astrophysics Data System (ADS)

An analysis of the short-characteristic method is described. The various approaches of the short-characteristic method are classified according to the degree of the interpolation scheme for the extinction/source function product. The accuracy of a difference scheme is quantified through two types of errors: the interpolation and the flux conservation errors. First- and high-order difference schemes equipped with interpolation and flux conservation error calculations are implemented in SHDOM. Results illustrating the accuracy of higher-order schemes are shown for realistic simulated clouds.

Doicu, Adrian; Efremenko, Dmitry; Trautmann, Thomas

2013-04-01

229

ATOMIC AND MOLECULAR PHYSICS: Retrieval of Electron Return Time from High-order Harmonics Generated in a Mixture of He and Ne Gases  

NASA Astrophysics Data System (ADS)

In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell's equation of harmonic held. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 (2007) 061403(R)] in macroscopic response level. Finally, using least squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 (2007) 153904] when the gas jet is put after the laser focus.

Jin, Cheng; Zhou, Xiao-Xin; Zhao, Song-Feng

2010-04-01

230

Flight crew physical fitness: A baseline analysis  

Microsoft Academic Search

Introduction: The purpose of this pilot study was to determine whether flight crew personnel are physically fit in comparison to published standards for the average American adult.Setting: The study group consisted of pilots, paramedics and nurses in two similarly configured and geographically located rotorwing air medical transport programs.Method: A physical fitness assessment of flight crew members was conducted. The results

Steve Shaner; Charles Brooks; Randy Osborn; Michael Hull; Robert E. Falcone

1995-01-01

231

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

232

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

PubMed Central

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

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

2008-01-01

233

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

234

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.

Campagnola, Paul

2011-01-01

235

Cost and performance analysis of physical security systems  

SciTech Connect

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

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

1998-04-01

236

Color harmonization for images  

NASA Astrophysics Data System (ADS)

Color harmonization is an artistic technique to adjust a set of colors in order to enhance their visual harmony so that they are aesthetically pleasing in terms of human visual perception. We present a new color harmonization method that treats the harmonization as a function optimization. For a given image, we derive a cost function based on the observation that pixels in a small window that have similar unharmonic hues should be harmonized with similar harmonic hues. By minimizing the cost function, we get a harmonized image in which the spatial coherence is preserved. A new matching function is proposed to select the best matching harmonic schemes, and a new component-based preharmonization strategy is proposed to preserve the hue distribution of the harmonized images. Our approach overcomes several shortcomings of the existing color harmonization methods. We test our algorithm with a variety of images to demonstrate the effectiveness of our approach.

Tang, Zhen; Miao, Zhenjiang; Wan, Yanli; Wang, Zhifei

2011-04-01

237

Analysis of interface carrier accumulation and relaxation in pentacene/C60 double-layer organic solar cell by impedance spectroscopy and electric-field-induced optical second harmonic generation  

NASA Astrophysics Data System (ADS)

By using the impedance spectroscopy (IS) and optical electric-field-induced second harmonic generation (EFISHG) measurement, interfacial carrier relaxation in pentacene/C60 double-layer organic solar cell (OSC) has been analyzed. The IS measurements showed that the interfacial carrier relaxation time was diminished 70 times under photo illumination, due to the increase of carrier density caused by the photovoltaic effect. The equivalent circuit analysis using a Maxwell-Wagner effect model well accounted for the IS results. On the other hand, the EFISHG measurements directly probed the interfacial carrier behaviors caused by the photovoltaic effect. The results showed the suppression of the Maxwell-Wagner type carrier relaxation in OSCs by applying a voltage corresponding to the open circuit voltage Voc. EFISHG measurement coupled with IS measurement provides a clear physics picture of interfacial phenomena related to the photovoltaic effect in OSCs.

Chen, Xiangyu; Taguchi, Dai; Shino, Tatsunori; Manaka, Takaaki; Iwamoto, Mitsumasa

2011-10-01

238

A Method of Non-linear Harmonic Analysis and its Application to Determination of Planetary Precession in DE405  

NASA Astrophysics Data System (ADS)

We developed a method of non-linear harmonic analysis. The algorithm determines (1) the coefficients of a quadratic polynomial representing the secular variation, the amplitudes and phases of Fourier terms, and the other linear parameters by the usual linear least square method, (2) the frequencies of Fourier terms and the other non-linear parameters by the BFGS algorithm of the quasi-Newton method (Broyden 1967), and (3) the number of the non-linear parameters by increasing it one by one from zero until the residual root mean square (RMS) becomes smaller than the required level for the noiseless data or until its decreasing manner becomes approximately flat for the noisy data. We accelerated the convergence of the algorithm by expanding the set of base functions so as to include the so-called mixed secular terms, namely the product of Fourier terms and a linear function. In order to find suitable initial guesses for the search in the quasi-Newton method, we extended the concept of periodogram to the case of mixed secular terms. As an application of the developed algorithm, we analysed the motion of the unit vector of the heliocentric orbital angular momentum of the Earth-Moon barycenter in the latest lunar/planetary ephemeris, DE405, as Standish (1982) did for DE102. After dropping 86 Fourier terms and 4 mixed secular terms detected, we determined the secular variation of two angles specifying the unit vector in the form of quadratic polynomials as ? = (-0.05240 +/- 0.00014) + (10.55318 +/- 0.00011) t + (0.49318 +/- 0.00004) t2, ? = (84381.41127 +/- 0.00006) + (-46.81265 +/- 0.00004) t + (0.04843 +/- 0.00002) t2 where the unit is arc second and t is the time since J2000.0 measured in Julian century. This is the latest determination of planetary precession formula in the inertial sense and referred to the ICRF.

Fukushima, T.; Harada, W.

2003-08-01

239

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

PubMed

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

Donoho, D L; Flesia, A G

2001-08-01

240

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

241

LivePhoto Physics Video Analysis Homework  

NASA Astrophysics Data System (ADS)

The LivePhoto Physics project is creating homework problems that require students to analyze videos of physical phenomena on their own computers. Some parts of the assignments resemble laboratory activities, some resemble context-rich problems, and some are more like traditional homework problems. After pilot testing with calculus-based introductory students at RIT, the project is beginning the beta testing phase. Sample assignments will be shown during this talk and the status of the testing will be discussed.

Allbaugh, Alicia

2005-03-01

242

Characterization of the Myosin-Based Source for Second-Harmonic Generation from Muscle Sarcomeres  

Microsoft Academic Search

Several biologically important protein structures give rise to strong second-harmonic generation (SHG) in their native context. In addition to high-contrast optical sections of cells and tissues, SHG imaging can provide detailed structural information based on the physical constraints of the optical effect. In this study we characterize, by biochemical and optical analysis, the critical structures underlying SHG from the complex

Sergey V. Plotnikov; Andrew C. Millard; Paul J. Campagnola; William A. Mohler

2006-01-01

243

Harmonic Allocation of Authorship Credit: Source-Level Correction of Bibliometric Bias Assures Accurate Publication and Citation Analysis  

PubMed Central

Authorship credit for multi-authored scientific publications is routinely allocated either by issuing full publication credit repeatedly to all coauthors, or by dividing one credit equally among all coauthors. The ensuing inflationary and equalizing biases distort derived bibliometric measures of merit by systematically benefiting secondary authors at the expense of primary authors. Here I show how harmonic counting, which allocates credit according to authorship rank and the number of coauthors, provides simultaneous source-level correction for both biases as well as accommodating further decoding of byline information. I also demonstrate large and erratic effects of counting bias on the original h-index, and show how the harmonic version of the h-index provides unbiased bibliometric ranking of scientific merit while retaining the original's essential simplicity, transparency and intended fairness. Harmonic decoding of byline information resolves the conundrum of authorship credit allocation by providing a simple recipe for source-level correction of inflationary and equalizing bias. Harmonic counting could also offer unrivalled accuracy in automated assessments of scientific productivity, impact and achievement.

Hagen, Nils T.

2008-01-01

244

Harmonic allocation of authorship credit: source-level correction of bibliometric bias assures accurate publication and citation analysis.  

PubMed

Authorship credit for multi-authored scientific publications is routinely allocated either by issuing full publication credit repeatedly to all coauthors, or by dividing one credit equally among all coauthors. The ensuing inflationary and equalizing biases distort derived bibliometric measures of merit by systematically benefiting secondary authors at the expense of primary authors. Here I show how harmonic counting, which allocates credit according to authorship rank and the number of coauthors, provides simultaneous source-level correction for both biases as well as accommodating further decoding of byline information. I also demonstrate large and erratic effects of counting bias on the original h-index, and show how the harmonic version of the h-index provides unbiased bibliometric ranking of scientific merit while retaining the original's essential simplicity, transparency and intended fairness. Harmonic decoding of byline information resolves the conundrum of authorship credit allocation by providing a simple recipe for source-level correction of inflationary and equalizing bias. Harmonic counting could also offer unrivalled accuracy in automated assessments of scientific productivity, impact and achievement. PMID:19107201

Hagen, Nils T

2008-12-24

245

Simple Harmonic Motion in Harmonic Plane Waves.  

ERIC Educational Resources Information Center

Discusses the distribution of kinetic and potential energy in transverse and longitudinal waves and examines the transmission of power and momentum. This discussion is intended to aid in understanding the simple harmonic motion of a particle involved in the propagation of a harmonic mechanical plane wave. (HM)

Benumof, Reuben

1980-01-01

246

Simple Harmonic Motion in Harmonic Plane Waves.  

ERIC Educational Resources Information Center

|Discusses the distribution of kinetic and potential energy in transverse and longitudinal waves and examines the transmission of power and momentum. This discussion is intended to aid in understanding the simple harmonic motion of a particle involved in the propagation of a harmonic mechanical plane wave. (HM)|

Benumof, Reuben

1980-01-01

247

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

248

Applied Harmonic Analysis.  

National Technical Information Service (NTIS)

Recent work by the CUNY group under the direction of Professor Louis Auslander has continued to study application of the Weil transform to radar signal processing and, in a parallel effort, to multi-access spread spectrum communications. The main thrust o...

L. Auslander

1993-01-01

249

Applied harmonic analysis  

NASA Astrophysics Data System (ADS)

Recent work by the CUNY group under the direction of Professor Louis Auslander has continued to study application of the Weil transform to radar signal processing and, in a parallel effort, to multi-access spread spectrum communications. The main thrust of the work is the relationship between the Weil transform of a waveform and the ambiguity surface of the wave-form. The study of this relationship has led to a fundamental observation: the cancellation properties of a waveform necessary for the creation of a thumbtack-like ambiguity surface may be viewed as arising from the pattern of zeros and the non-trivial winding numbers of the Weil transform of the waveform. This point of view is exposited and used to reinterpret classical radar waveform design techniques, while also providing a new method for radar waveform design. Additionally, a new technique for modifying or shaping waveforms has been developed. This consists of changing a waveforms has been developed. This consists of changing a waveform by multiplying its Weil transform by doubly-periodic functions and taking the inverse Weil transform to produce a new signal.

Auslander, Louis

1993-08-01

250

Harmonization of Biodiesel Specifications  

SciTech Connect

Worldwide biodiesel production has grown dramatically over the last several years. Biodiesel standards vary across countries and regions, and there is a call for harmonization. For harmonization to become a reality, standards have to be adapted to cover all feedstocks. Additionally, all feedstocks cannot meet all specifications, so harmonization will require standards to either tighten or relax. For harmonization to succeed, the biodiesel market must be expanded with the alignment of test methods and specification limits, not contracted.

Alleman, T. L.

2008-02-01

251

MR harmonic quad study  

SciTech Connect

To understand the effect of Main Ring harmonic quadruple correctors. Previous data taken with the harmonic quads did not agree well with the SYNCH calculation. The ultimate goal of this study was to be able to change the harmonic quads and verify the changes in lattice function.

Yang, M.-J.; /Fermilab

1995-01-01

252

Pathway of bichromatic high-order harmonic generation  

SciTech Connect

We present a theoretical study of the pathway of harmonic generation in bichromatic linearly polarized laser fields. A 'harmonic-collapse' phenomenon is observed in the power spectrum for a particular value of the amplitude ratio of two components of the external field. We employ an offset frequency shift to the additional field to distinguish the harmonic pathway and then to explain the harmonic-collapse phenomenon. The harmonic intensity as a function of the relative amplitude ratio and, furthermore, the fine structure of the harmonic spectrum can be well understood on the basis of a pathway analysis.

Cai, Jun; Qiao, Haoxue [Department of Physics, Wuhan University, Wuhan 430072 (China)

2007-03-15

253

Measuring noninertial physics of turbulence: quasiscaling analysis.  

PubMed

Quasiscaling exponent zeta(n)(M;D) is introduced by the ratio of turbulence velocity structure functions S(n) (r(D))/S(n)(r(M)) = (r(D)/r(M))(zeta(n)(M;D)) at scales r(M) and r(D) 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 non-conservative 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. PMID:16196707

Zhu, Jian-Zhou

2005-08-18

254

Shape analysis of brain structures using physical and experimental modes  

Microsoft Academic Search

We present a framework for analyzing the shape of structures within the human brain. A mathematical model is developed describing the deformation of any brain structure whose shape is affected by both gross and detailed physical processes. The total shape deformation is decomposed into physical modes of variation obtained from finite element analysis, and experimental modes of variation obtained from

John Martin; Alex Pentland; Ron Kikinis

1994-01-01

255

Dimensional Analysis in Physics and the Buckingham Theorem  

ERIC Educational Resources Information Center

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

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

2010-01-01

256

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.

257

Second harmonic microscopy of axonemes.  

PubMed

We performed Second Harmonic Microscopy of axonemes obtained from sea urchin sperm. Using polarization analysis and a trade-off between signal and photodamage, we were able to determine, for the first time to our knowledge, the nonlinear susceptibility chizxx/chixzx = 1.1+/-0.2 and chizzz/chixzx = 4+/-0.5 of axonemes. PMID:19466174

Odin, Christophe; Heichette, Claire; Chretien, Denis; Le Grand, Yann

2009-05-25

258

Relaxation-based harmonic balance technique for semiconductor device simulation  

Microsoft Academic Search

Harmonic and intermodulation distortion effects play an important role in numerous analog applications, particularly in such areas as wireless communication systems. In this paper, we present a two-dimensional harmonic balance semiconductor device simulator which accurately models these nonlinear effects at the physical (drift-diffusion) level. The simulator is based on Stanford University's PISCES code, and supports the full range of physical

Boris Troyanovsky; Zhiping Yu; Lydia So; Robert W. Dutton

1995-01-01

259

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

260

Harmonic motion analysis and control for manipulating objects with a power assist robot based on human characteristics  

Microsoft Academic Search

We developed a one-degree-of-freedom (vertical up-down motion) power assist robot for manipulating objects. The robot system was simulated and subjects manipulated objects with the robot in harmonic motion i.e. the objects were repeatedly lifted up and lowered down during the simulation. We then critically analyzed human's weight perception, load forces and object's motion features. We then introduced a novel control

S. M. M. Rahman; R. Ikeura; M. Nobe; H. Sawai

2010-01-01

261

Manipulating objects with a power assist robot in harmonic motion: Analysis of human features and object motions for control modification  

Microsoft Academic Search

We designed a one-degree-of-freedom (vertical up-down motion) power assist robot for manipulating objects. We used a hypothesis that pertains to human's weight perception. The robot was simulated and subjects manipulated objects with the robot in harmonic motion i.e. the objects were repeatedly lifted up and lowered down in each trial. We then critically analyzed subject's weight perception, load forces and

S. M. Mizanoor Rahman; Ryojun Ikeura; Hideki Sawai

2010-01-01

262

Simulation of a High Harmonic Gyrotron with Axis-Encircling Electron Beam and Permanent Magnet  

Microsoft Academic Search

A computer code for simulation of beam-field interaction in a resonant cavity of a gyrotron has been developed. It is based on a self-consistent, time-independent, single-mode physical model. The code has been applied to the analysis of the electrodynamical system of a novel high-harmonic gyrotron with axis-encircling beam and a permanent magnet. In this paper both the physical model and

S. Sabchevski; T. Idehara; I. Ogawa; M. Glyavin; K. Ohashi

2002-01-01

263

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

264

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

NASA Astrophysics Data System (ADS)

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

Al-Shyyab, A.; Kahraman, A.

2005-06-01

265

Harmonic considerations for electrical distribution feeders  

NASA Astrophysics Data System (ADS)

Harmonics on the electric power distribution system can cause motor overheating, capacitor failures,watt-hour meter error, and relay malfunctions. The degree of problems caused by harmonics is greatly dependent on the characteristics of the distribution feeder, which can absorb a considerable percentage of its capacity in harmonic currents without ill effects. However, power factor correction capacitors can cause resonances near harmonic voltages that can result in intolerable distortion. Both motor loads and resistive loads can decrease the effect of resonance significantly. This report describes useful techniques to analyze, suppress, and measure harmonics on distribution feeders. Applicable areas for manual analysis and computer analysis are explained. The basic formulae are presented as well as sophisticated computer methods. Emphasis is placed on the fundamental principle. Models of harmonic-producing devices are presented and their limitations discussed. Most distribution feeder harmonics analyses can be performed using simple current source models. Filtering of specific loads and general, dispersed load is discussed. The fundamental principle in filtering distribution feeders is to shorten the harmonic current path. 3-dimensional plots enhance the understanding of the filtering action. Equipment and procedures for making measurements are described.

1988-03-01

266

Harmonic considerations for electrical distribution feeders  

SciTech Connect

Harmonics on the electric power distribution system can cause motor overheating, capacitor failures, watthour meter error, and relay malfunctions. The degree of problems caused by harmonics is greatly dependent on the characteristics of the distribution feeder. A typical distribution feeder can absorb a considerable percentage of its capacity in harmonic currents without ill effects. However, power factor correction capacitors can cause resonances near harmonic voltages that can result in intolerable distortion. Both motor loads and resistive loads can decrease the effet of resonance significatnly. This report describes useful techniques to analyze, suppress, and measure harmonics on distribution feeders. Applicable areas for manual analysis and computer analysis are explained. The basic formulae are presented as well as sophisticated omputer methods. Emphasis is placed on the fundamental principle. Models of harmonic-producing devices are presented and their limitations discussed. Most distribution feeder harmonics analyses can be performed using simple current source models. Filtering of specific loads and general, dispersed load is discussed. The fundamental principle in filtering distribution feeders is to shorten the harmonic current path. 3-dimensional plots enhance the understanding of the filtering action. Equipment and procedures for making measurements are described.

Not Available

1988-03-01

267

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

268

Dimensional analysis in physics and the Buckingham theorem  

NASA Astrophysics Data System (ADS)

Dimensional analysis is a simple, clear and intuitive method for determining the functional dependence of physical quantities that are of importance to a certain process. However, in physics textbooks, very little space is usually given to this approach and it is often presented only as a diagnostic tool used to determine the validity of dependences otherwise obtained. This paper presents the basics of dimensional analysis in two cases: the resistance force of the fluid that occurs when a body moves through it and the speed of propagation of waves on water. After that, a general approach to dimensional analysis based on the Buckingham theorem is shown. The material presented in the paper could be useful to both students of physics and physics graduates.

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

2010-07-01

269

Synchronous Discrete Harmonic Oscillator  

SciTech Connect

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

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

2008-10-17

270

On the Correct Analysis of the Foundations of Theoretical Physics  

NASA Astrophysics Data System (ADS)

The problem of truth in science -- the most urgent problem of our time -- is discussed. The correct theoretical analysis of the foundations of theoretical physics is proposed. The principle of the unity of formal logic and rational dialectics is a methodological basis of the analysis. The main result is as follows: the generally accepted foundations of theoretical physics (i.e. Newtonian mechanics, Maxwell electrodynamics, thermodynamics, statistical physics and physical kinetics, the theory of relativity, quantum mechanics) contain the set of logical errors. These errors are explained by existence of the global cause: the errors are a collateral and inevitable result of the inductive way of cognition of the Nature, i.e. result of movement from formation of separate concepts to formation of the system of concepts. Consequently, theoretical physics enters the greatest crisis. It means that physics as a science of phenomenon leaves the progress stage for a science of essence (information). Acknowledgment: The books ``Surprises in Theoretical Physics'' (1979) and ``More Surprises in Theoretical Physics'' (1991) by Sir Rudolf Peierls stimulated my 25-year work.

Kalanov, Temur Z.

2007-04-01

271

Linear regression analysis in a first physics lab  

Microsoft Academic Search

Linear regression analysis (least squares) is used in the first physics lab in order to introduce students to computer-aided analysis and to teach data fitting techniques. Application is made to two experiments: Fletcher's trolley and Hooke's law. Least squares will extract information from raw data in a very precise way, and it opens the way for the study of more

Lawrence Hmurcik; Amy Slacik; Hilda Miller; Sandy Samoncik

1989-01-01

272

High-Speed Video Analysis in a Conceptual Physics Class  

ERIC Educational Resources Information Center

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

Desbien, Dwain M.

2011-01-01

273

Active Harmonic Filters  

Microsoft Academic Search

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

HIROFUMI AKAGI

2005-01-01

274

Online Data Collection and Analysis in Introductory Physics  

NASA Astrophysics Data System (ADS)

Online implementation of physics learning materials may present a powerful method of data collection for physics education research, in addition to being useful for supplemental instruction. This may have implications for composite instruction and research designs. We have developed three lessons on Newton's laws and implemented them on the Internet. The lessons ask students to make observations and measurements using video clips, perform calculations and answer open-ended questions. Responses are collected via an online response system. One hundred ten university students enrolled in an algebra-based physics course and 30 high school physics students worked through some or all of our lessons, and their responses were collected. We present a qualitative and quantitative analysis of their responses and assess the implications for optimal design of online lesson materials for collecting meaningful data about students' understanding of basic physics concepts.

Nakamura, Christopher M.; Murphy, Sytil K.; Juma, Nasser M.; Rebello, N. Sanjay; Zollman, Dean

2009-11-01

275

Online Data Collection and Analysis in Introductory Physics  

NSDL National Science Digital Library

Online implementation of physics learning materials may present a powerful method of data collection for physics education research, in addition to being useful for supplemental instruction. This may have implications for composite instruction and research designs. We have developed three lessons on Newtonâs laws and implemented them on the Internet. The lessons ask students to make observations and measurements using video clips, perform calculations and answer open-ended questions. Responses are collected via an online response system. One hundred ten university students enrolled in an algebra-based physics course and 30 high school physics students worked through some or all of our lessons, and their responses were collected. We present a qualitative and quantitative analysis of their responses and assess the implications for optimal design of online lesson materials for collecting meaningful data about studentsâ understanding of basic physics concepts.

Nakamura, Christopher M.; Murphy, Sytil K.; Juma, Nasser M.; Rebello, N. S.; Zollman, Dean A.

2010-01-19

276

Geomagnetic local and regional harmonic analyses.  

USGS Publications Warehouse

Procedures are developed for using rectangular and cylindrical harmonic analyses in local and regional areas. Both the linear least squares analysis, applicable when component data are available, and the nonlinear least squares analysis, applicable when only total field data are available, are treated. When component data are available, it is advantageous to work with residual fields obtained by subtracting components derived from a harmonic potential from the observed components. When only total field intensity data are available, they must be used directly. Residual values cannot be used. Cylindrical harmonic analyses are indicated when fields tend toward cylindrical symmetry; otherwise, rectangular harmonic analyses will be more advantageous. Examples illustrating each type of analysis are given.-Author

Alldredge, L. R.

1982-01-01

277

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

278

Geopotential harmonics of order 15 and 30, from analysis of the orbit of satellite 1971-10B  

NASA Astrophysics Data System (ADS)

The satellite 1971-10B passed through exact 15th-order resonance on 30 March 1981 and orbital parameters have been determined at 52 epochs from some 3500 observations using the RAE orbit refinement program, PROP,between September 1980 and October 1981. The variations in inclination and eccentricity during this time have been analysed, and six lumped 15th-order harmonic coefficients and two 30th-order coefficients have been evaluated. The 15th-order coefficients are the best yet obtained for an orbital inclination near 65 deg; and previously there were no 30th-order coefficients available at this inclination. The lumped coefficients have been used to test the Goddard Earth Model GEM 10B: there is good agreement for seven of the eight coefficients.

Walker, D. M. C.

1985-01-01

279

Geopotential harmonics of order 15 and 30, from analysis of the orbit of satellite 1971-10B  

NASA Astrophysics Data System (ADS)

The Cosmos satellite 1971-10B passed through exact 15th-order resonance on March 30, 1981, and orbital parameters were determined at 52 epochs from 3500 observations using the orbit refinement program PROP, between 1980 September and 1981 October. The variations in inclination and eccentricity during this time were analyzed, and 6 lumped 15th-order harmonic coefficients and two 30th-order coefficients were evaluated. The 15th-order coefficients are the best yet obtained for an orbital inclination near 65 deg; previously there were no 30th-order coefficients available at this inclination. The lumped coefficients were used to test the Goddard Earth Model GEM 10B; there is good agreement for 7 of the 8 coefficients.

Walker, D. M. C.

1984-01-01

280

Harmonic Scalpel Compared to Conventional Hemostasis in Thyroid Surgery: A Meta-Analysis of Randomized Clinical Trials  

PubMed Central

Background. The study's aim was to determine whether conventional hemostasis (CH) or the Harmonic Scalpel (HS) results in shorter operative times for thyroidectomy and to evaluate the incidence of postoperative complications with each approach. Methods. A literature search was conducted from study inception to September 30, 2008. Included studies randomized thyroidectomy patients to either CH or HS and reported the incidence of postoperative transient recurrent laryngeal nerve dysfunction (RLND) and hypocalcemia. Results. Nine RCTs were included. Use of the HS reduced operative time by 23.1 minutes (95% CI?=?13.8, 32.33). There was no difference in the incidence of transient RLND (RR?=?1.25, 95% CI?=?.56, 2.76), but a lower rate of transient hypocalcemia with the use of the HS (RR?=?.69, 95% CI?=?.51, .92). Conclusions. The use of HS in thyroidectomy significantly reduces operative time and is associated with a reduction in postoperative hypocalcemia compared to CH.

Melck, Adrienne L.; Wiseman, Sam M.

2010-01-01

281

Numerical analysis of broadband second harmonic generation using TIR-QPM in a parabolic profiled isotropic semiconductor slab  

NASA Astrophysics Data System (ADS)

We report second harmonic generation (SHG) with a flat wide bandwidth accompanied by good conversion efficiency in an isotropic semiconductor slab with a parabolic upper profile. The concept of SHG conversion stands on the principle of total internal reflection quasi-phase matching (TIR-QPM). A simulation has been performed using GaAs as the non-linear material, in the fundamental wavelength range of 6.8-10.8 ?m, considering ppp polarization configuration. Optimized simulation results, after considering reflection and absorption losses, show a flatter bandwidth of 642 nm in a 36 mm slab in comparison to a dipped 3 dB bandwidth of 770 nm in an elliptically profiled isotropic slab as well as a steeper bandwidth of 187 nm in a tapered isotropic slab. The present simulation shows an acceptable conversion efficiency of 1.105%.

Banik, Smita; Das, Upama; Deb, Sumita; Saha, Ardhendu

2013-05-01

282

Analysis of regional cadiac performance with higher-order harmonics of Fourier series in coronary artery disease  

SciTech Connect

The authors have previously reported the optimum order harmonics of Fourier series in multigated blood-pool studies. To assess regional cardiac performance, a computer assisted method has been developed for analyzing regional volume curve. Eight normals and 18 with coronary artery disease (CAD) were studied at rest. After list mode data acquisition, serial 30 msec frames were created. Following automatic selection of the left ventricle (LV), the geometric center was determined, and the LV was subdivided into 8 sectors with equi-angular spacing. Regional volume curves of 6 sectors were analysed. To minimize statistical noise, each curve was fitted by third-order harmonics of Fourier series. Regional ejection fraction (rEF), peak ejection rate (rPER), peak filling rate (rPFR), time to end-systole (rTES), time to PER (rTPE), and time to PFR (rTPF) were calculated from each fitted curve. Those with rEF, rPER, or rPFR lower than the lower limit (mean-250) of the normal values were considered abnormal (asynergy). Those with rTES, rTPE, or rTPF greater than or equal to 90 msec longer or shorter than the global value of LV were considered abnormal (asynchrony). Regional asynergy was seen in 12 cases of the CAD (67%), while asynchrony was observed in 13 (72%). Three of them showed asynchrony with normal rEF, rPER, and rPFR (1 rTES, 1 rTPF, and 1 both abnormalities). The specificity was 88% for rEF and rPER, 75% for rPFR and 75-88% for time indexes. Thus, this technique permits spatial and temporal evaluation of regional LV wall motion. Those newly acquired parameters seem to be valuable for the detection and localization of CAD.

Tamaki, N.; Kodama, S.; Yonekura, Y.; Senda, M.; Minato, K.; Mukai, T.; Torizuka, K.; Nakamura, T.

1984-01-01

283

Harmonics generated from a DC biased transformer  

SciTech Connect

The paper presents harmonic characteristics of transformer excitation currents under DC bias caused by geomagnetically induced currents (GIC). A newly developed saturation model of a single phase shell form transformer based on 3D finite element analysis is used to calculate the excitation currents. As a consequence, the complete variations of excitation current harmonics with respect to an extended range of GIC bias are revealed. The results of this study are useful in understanding transformers as harmonic sources and the impact on power systems during a solar magnetic disturbance.

Shu Lu; Yilu Liu; Ree, J. De La (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). The Bradley Dept. of Electrical Engineering)

1993-04-01

284

Investigation of non-linear devices modeled as a harmonic current source  

Microsoft Academic Search

IEEE std. 519-1992 recommends that nonlinear devices can be modeled generally as a harmonic current source. However, some literatures propose that the voltage-source nonlinear devices actually behave as a harmonic voltage source. The need to verify if nonlinear devices can be treated as harmonic current sources in power system analysis and harmonic mitigation remains strong and challenging. In this paper,

Xiaodong Liang; William Jackson

2008-01-01

285

Harmonic synchronization of nonlinear oscillators  

Microsoft Academic Search

The locking range of a harmonic synchronized oscillator is calculated, and it is shown to be proportional to the relative harmonic amplitude produced by the nonlinearity. For completeness a simple method is given for calculating the harmonic output produced.

I. Schmideg

1971-01-01

286

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

287

Creativity in theoretical physics: A situational analysis of the fifth Solvay Council on Physics, 1927  

NASA Astrophysics Data System (ADS)

This dissertation investigates the intersections and interactions of factors which enhance and inhibit creativity in theoretical physics research, using a situational analysis of the fifth Solvay Council on Physics of 1927 (Solvay 1927), a pivotal point in the history of quantum physics. Situational analysis is a postmodern variant of the grounded theory method which views a situation as the unit of analysis and adds situational mapping as an analytic tool. This method specifically works against normalizing or simplifying the points of view, instead drawing out diversity, complexity, and contradiction. It results in "theorizing" rather than theory. This research differs from other analyses of the development of quantum mechanics in looking at technical issues as well as individual, collective, and societal factors. Data examined in this historical analysis includes theoretical papers, conference proceedings, personal letters, and commentary and analysis, both contemporaneous and modern. Literature related to scientific creativity was also consulted. Mapping the situation as a master discourse of Niels Bohr overlapping and interacting with co-existent major discourses on matrix mechanics/Copenhagen interpretation, wave mechanics, and the pilot-wave theory resulted in the most descriptive illustration of the factors influencing scientific creativity before and after Solvay 1927. The master discourse strongly influenced the major discourses and generated the "Copenhagen spirit" which effectively marginalized discourses other than matrix mechanics/Copenhagen interpretation after Solvay 1927.

First, Leili K.

288

High-Speed Video Analysis in a Conceptual Physics Class  

Microsoft Academic Search

The use of probe ware and computers has become quite common in introductory physics classrooms.1 Video analysis is also becoming more popular and is available to a wide range of students through commercially available and\\/or free software.2,3 Video analysis allows for the study of motions that cannot be easily measured in the traditional lab setting and also allows real-world situations

Dwain M. Desbien

2011-01-01

289

The Ergonomic Analysis of the Workplace of Physically Disabled Individuals  

Microsoft Academic Search

This paper presents a new gesture-based approach for the ergonomic evaluation of the workplaces of the physically handicapped.\\u000a After a brief overview of tools using interactive simulation to perform ergonomic analysis, we describe the requirements to\\u000a perform ergonomic analyses for the disabled. We then propose a framework unifying the synthesis and analysis of motions and\\u000a integrating a model of disabilities

Matthieu Aubry; Frédéric Julliard; Sylvie Gibet

2007-01-01

290

Applications of nonlinear time series analysis in solar physics  

Microsoft Academic Search

We applied methods of nonlinear time series analysis to different aspects of the solar phenomenology, as the solar cycle, the solar granulation and solar radio bursts. The methods include tests for deterministic chaos hidden in the data, as the determination of global attractor dimensions. However, in solar physics we deal with \\

A. Veronig; M. Messerotti; A. Hanslmeier

2000-01-01

291

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…

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

2012-01-01

292

Soil Studies: Physical and Chemical Analysis, Native and Retort Soils.  

National Technical Information Service (NTIS)

This report contains data from the physical and chemical analysis of native soils and retort soils from the Geokinetics Oil Shale Site, Uintah County, Utah. Four native soil types were sampled: loam, JR loam, Havre silt loam, and Luhon loam. Samples from ...

E. R. Olgeirson

1979-01-01

293

Noncommutative analysis and quantum physics I. States and ensembles  

Microsoft Academic Search

In this sequence of papers, noncommutative analysis is used to give a consistent axiomatic approach to a unified conceptual foundation of classical and quantum physics. The present Part I defines the concepts of observables, states and ensembles, clarifies the logical relations and operations for them, and shows how they give rise to dynamics and probabilities. States are identified with maximal

Arnold Neumaier

1999-01-01

294

Harmonic distortion in microwave photonic filters.  

PubMed

We present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation. PMID:22513597

Rius, Manuel; Mora, José; Bolea, Mario; Capmany, José

2012-04-01

295

Ultrathin harmonic generators  

SciTech Connect

In second-harmonic generation in optical materials with extremely large nonlinearity (about 1,000 that in KDP), efficient conversion may be expected for gain lengths of just a few micrometers. If the gain length is less than the coherence length, the phase-matching condition normally invoked for KDP and other common nonlinear materials may not apply. Devices based on such ultrathin media are potentially insensitive to wavelength, bandwidth, temperature, and poor beam quality. The authors have analyzed harmonic generation in ultrathin media to evaluate their materials requirements. They show that in such devices the conversion efficiency to the second harmonic is necessarily limited to about 25%, because higher harmonics are also necessarily generated with significant efficiencies. Ultrathin devices are therefore subject to large thermal loads, and perhaps optical damage arising from the generation of strong ultraviolet or soft X-ray harmonics. Whereas ultrathin media are not as efficient as conventional phase-matched crystals for second-harmonic generation, they do generate phase-coherent, multiple higher harmonics. As a consequence, they can generate optical square waves electromagnetic shock waves, and may find application as coherent soft X-ray generators.

Eimerl, D. (Lawrence Livermore National Lab., CA (United States). Nonlinear Optical Materials Group)

1991-09-01

296

[Quantitative analysis of psychometric indicators among 40-55 years old accelerant Georgian men and women of normal physical development].  

PubMed

Determination of individual characteristics of a human being causes much interest. Furthermore, you can seldom come across the studies about determination of psychological categories of accelerants. The aim of the present work was to determine quantitative analysis of psychometric indicators among 40-55 years old accelerant Georgian men and women of normal physical development for given age scales as well as to determine personal characteristics of each person to be researched. On the basis of conducted research we may shape out, that older Georgian women are characterized with phlegmatic temperament and introversive character. They are observed to have average degree of logic and verbal intellect; constitutional types of mid exciting, conflicting and static mood. While elder Georgian men have sanguine temperament, they are characterized with extroversive character, average degree of logic intellect, plastic-dynamic and constitutional-stable mood; they are considered to be harmonic and dynamic constitutional types. We have also established that Georgian accelerant men are observed to have phlegmatic temperament, extroversion, average mathematical intellect and conflicting and static mood. Accelerant Georgian women displayed phlegmatic temperament, extroversion, average logic intellect, and conflicting and static mood. But still they were observed, though seldom, to have harmonic and dynamic character. PMID:16705251

Nadashvili, L A

2006-04-01

297

Exploring a photonic quasi-crystal fiber for enhancing the efficiency of second harmonic generation: Modeling and analysis  

NASA Astrophysics Data System (ADS)

In this paper, we explore the possibility of using a new type of microstructured optical fiber called photonic quasi-crystal fiber (PQF) for enhancing the efficiency of second harmonic generation (SHG). We model a six-fold, index guided, silica core PQF with a relative air hole diameter ranging from 0.1-0.5. We compute the various factors related to SHG, namely, phase mismatch factor, wave-vector mismatch, coherence length, quasi-phase matching length and overlap area. Of the various factors, we focus more on the role of wave-vector mismatch and overlap area as these parameters are highly sensitive to the variations in the geometrical arrangement of air holes in the cladding. Further, these parameters are required to be as minimum as possible for enhancing the efficiency of SHG. We find that the wave-vector mismatch factor does decrease for higher values of pitch and for lower values of relative air hole diameter. However, the overlap area increases for higher values of pitch and for lower values of relative air hole diameter. Therefore, we optimize the hitherto mentioned parameters such that the wave-vector mismatch is 0.145 ?m-1 and the overlap area is 3.48 ?m2. With these values, we demonstrate a relative efficiency of 62.96% W-1 cm-2 with the proposed PQF.

Bhattacharjee, Ritapa; Senthilnathan, K.; Sivabalan, S.; Ramesh Babu, P.

2013-10-01

298

Reactor Physics Methods and Analysis Capabilities in SCALE  

SciTech Connect

The TRITON sequence of the SCALE code system provides a powerful, robust, and rigorous approach for performing reactor physics analysis. This paper presents a detailed description of TRITON in terms of its key components used in reactor calculations. The ability to accurately predict the nuclide composition of depleted reactor fuel is important in a wide variety of applications. These applications include, but are not limited to, the design, licensing, and operation of commercial/research reactors and spent-fuel transport/storage systems. New complex design projects such as next-generation power reactors and space reactors require new high-fidelity physics methods, such as those available in SCALE/TRITON, that accurately represent the physics associated with both evolutionary and revolutionary reactor concepts as they depart from traditional and well-understood light water reactor designs.

Mark D. DeHart; Stephen M. Bowman

2011-05-01

299

Soliton ratchetlike dynamics by ac forces with harmonic mixing.  

PubMed

The possibility of unidirectional motion of a kink (topological soliton) of a dissipative sine-Gordon equation in the presence of ac forces with harmonic mixing (at least biharmonic) and of zero mean, is presented. The dependence of the kink mean velocity on system parameters is investigated numerically and the results are compared with a perturbation analysis based on a point-particle representation of the soliton. We find that first order perturbative calculations lead to incomplete descriptions, due to the important role played by the soliton-phonon interaction in establishing the phenomenon. The role played by the temporal symmetry of the system in establishing soliton dc motions that resemble usual soliton ratchets, is also emphasized. In particular, we show the existence of an asymmetric internal mode on the kink profile that couples to the kink translational mode through the damping in the system. Effective soliton transport is achieved when the internal mode and the external force get phase locked. We find that for kinks driven by biharmonic drivers consisting of the superposition of a fundamental driver with its first odd harmonic, the transport arises only due to this internal mode mechanism, while for biharmonic drivers with even harmonic superposition, also a point-particle contribution to the drift velocity is present. The phenomenon is robust enough to survive the presence of thermal noise in the system and can lead to several interesting physical applications. PMID:12059727

Salerno, Mario; Zolotaryuk, Yaroslav

2002-04-29

300

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

301

Lasing on higher harmonics  

SciTech Connect

Lasing at short wavelengths with an accelerator of modest energy can only be achieved with a wiggler of short period and high field operating, perhaps, at a high harmonic of the fundamental frequency. We discuss the characteristics of wigglers of this kind, designed to lase with harmonic numbers as large as fifty or so, emphasizing their gain, efficiency, and sensitivity to emittance and energy spread. 5 refs., 3 figs.

Warren, R.W.

1990-01-01

302

Data Preservation and Long Term Analysis in High Energy Physics  

NASA Astrophysics Data System (ADS)

Several important and unique experimental high-energy physics programmes at a variety of facilities are coming to an end, including those at HERA, the B-factories and the Tevatron. The wealth of physics data from these experiments is the result of a significant financial and human effort, and yet until recently no coherent strategy existed for data preservation and re-use. To address this issue, an inter-experimental study group on data preservation and long-term analysis in high-energy physics was convened at the end of 2008, publishing an interim report in 2009. The membership of the study group has since expanded, including the addition of the LHC experiments, and a full status report has now been released. This report greatly expands on the ideas contained in the original publication and provides a more solid set of recommendations, not only concerning data preservation and its implementation in high-energy physics, but also the future direction and organisational model of the study group. The main messages of the status report were presented for the first time at the 2012 International Conference on Computing in High Energy and Nuclear Physics and are summarised in these proceedings.

South, D. M.

2012-12-01

303

Theoretical analysis of electromagnetic field distribution and Cerenkov second harmonic generation conversion efficiency based on lithium niobate ion-implanted channel waveguide  

Microsoft Academic Search

Cerenkov type second harmonic generation (CSHG) is proposed in ion-implanted Z-cut lithium niobate (LiNbO3) channel waveguides. We have obtained exact analytical solutions for the field distribution and the power of second-harmonic waves. Conditions for attaining higher conversion efficiency are discussed on the basis of numerical calculations.

G. L. Du; G. Q. Li; S. Z. Zhao; T. Li; X. Li

304

QA/QC requirements for physical properties sampling and analysis  

SciTech Connect

This report presents results of an assessment of the available information concerning US Environmental Protection Agency (EPA) quality assurance/quality control (QA/QC) requirements and guidance applicable to sampling, handling, and analyzing physical parameter samples at Comprehensive Environmental Restoration, Compensation, and Liability Act (CERCLA) investigation sites. Geotechnical testing laboratories measure the following physical properties of soil and sediment samples collected during CERCLA remedial investigations (RI) at the Hanford Site: moisture content, grain size by sieve, grain size by hydrometer, specific gravity, bulk density/porosity, saturated hydraulic conductivity, moisture retention, unsaturated hydraulic conductivity, and permeability of rocks by flowing air. Geotechnical testing laboratories also measure the following chemical parameters of soil and sediment samples collected during Hanford Site CERCLA RI: calcium carbonate and saturated column leach testing. Physical parameter data are used for (1) characterization of vadose and saturated zone geology and hydrogeology, (2) selection of monitoring well screen sizes, (3) to support modeling and analysis of the vadose and saturated zones, and (4) for engineering design. The objectives of this report are to determine the QA/QC levels accepted in the EPA Region 10 for the sampling, handling, and analysis of soil samples for physical parameters during CERCLA RI.

Innis, B.E.

1993-07-21

305

High-Speed Video Analysis in a Conceptual Physics Class  

NASA Astrophysics Data System (ADS)

The use of probe ware and computers has become quite common in introductory physics classrooms.1 Video analysis is also becoming more popular and is available to a wide range of students through commercially available and/or free software.2,3 Video analysis allows for the study of motions that cannot be easily measured in the traditional lab setting and also allows real-world situations to be analyzed. Many motions are too fast to easily be captured at the standard video frame rate of 30 frames per second (fps) employed by most video cameras. This paper will discuss using a consumer camera that can record high-frame-rate video in a college-level conceptual physics class. In particular this will involve the use of model rockets to determine the acceleration during the boost period right at launch and compare it to a simple model of the expected acceleration.

Desbien, Dwain M.

2011-09-01

306

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR  

Microsoft Academic Search

Detailed reactor physics and safety analyses have been performed for the 20 MW DO moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional MCNP Monte Carlo neutron and photon transport calculations were performed to determine the safety parameters

J. CHENG; L. HANSON; J. RORER; D. DIAMOND

2003-01-01

307

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR  

Microsoft Academic Search

Detailed reactor physics and safety analyses have been performed for the 20 MW DO moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron and photon transport calculations were performed with the MCNP code to determine

L. HANSON; A. DIAMOND; D. XU; J. CAREW; J. RORER

2004-01-01

308

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

309

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

310

Physics analysis of the gang partial rod drive event  

SciTech Connect

During the routine positioning of partial-length control rods in Gang 3 on the afternoon of Monday, July 27, 1992, the partial-length rods continued to drive into the reactor even after the operator released the controlling toggle switch. In response to this occurrence, the Safety Analysis and Engineering Services Group (SAEG) requested that the Applied Physics Group (APG) analyze the gang partial rod drive event. Although similar accident scenarios were considered in analysis for Chapter 15 of the Safety Analysis Report (SAR), APG and SAEG conferred and agreed that this particular type of gang partial-length rod motion event was not included in the SAR. This report details this analysis.

Boman, C.; Frost, R.L.

1992-08-01

311

Statistics and music: Fitting a local harmonic model to musical sound signals  

NASA Astrophysics Data System (ADS)

Statistical modeling and analysis have been applied to different music related fields. One of them is sound synthesis and analysis. Sound can be represented as a real-valued function of time. This function can be sampled at a small enough rate so that the resulting discrete version is almost as good as the continuous one. This permits one to study musical sounds as a discrete time series, an entity for which many statistical techniques are available. Physical modeling suggests that many musical instruments' sounds are characterized by a harmonic and an additive noise signal. The noise is not something to get rid of rather it's an important part of the signal. In this research the interest is in separating these two elements of the sound. To do so a local harmonic model that tracks changes in pitch and of the amplitude of the harmonics is fit. Deterministic changes in the signal, such as pitch change, suggest that different temporal window sizes should be considered. Various ways to choose appropriate window sizes are studied. Amongst other things our analysis provides estimates of the harmonic signal and of the noise signal. Different musical composition applications may be based on the estimates.

Irizarry, Rafael Angel

312

NASA Space Plasma Physics Research and Analysis Program  

NASA Astrophysics Data System (ADS)

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 that is not tied to specific missions. Although funding levels for space plasma physics to date have not kept up with inflation (overall funding levels are reduced 30% over the past decade when corrected for inflation), the R&A program is beginning to recover, as shown in Figure 1, thanks to a “vitality package” augmentation in fiscal years (FY) 1987 and 1988. Budget totals for the sounding rocket (SR), instrument development, and solar-terrestrial theory (STTP) programs are also shown for comparison (see Eos, April 28, 1987, p. 483). Fiscal health of the R&A program is important to these other programs as well. Although budget authorizations are made strictly on a year-to-year basis, there are several positive signs suggesting that the current upward trend for space plasma physics programs could last several years.

Eastman, Timothy E.

313

Optical harmonic generator  

DOEpatents

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

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

1985-01-01

314

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

315

Analysis of the physical mechanisms behind the Weddell Sea Anomaly using a physics-based data assimilation model  

NASA Astrophysics Data System (ADS)

The Weddell Sea Anomaly (WSA) is a mid-latitude F region ionosphere phenomena taking place over the regions west of the Antarctic Peninsula. It is most prominent during local summer, is characterized by larger electron densities at night than at noon and completely disappears during winter. Though the WSA has been known for several decades, its generation mechanism is not fully understood and its modeling remains a challenge. In the current study the GPS radio occultation measurements from the six FORMOSAT-3/COSMIC satellites combined with a physics-based data assimilation model of the ionosphere were used to understand the physical mechanism behind the WSA generation. The data assimilation model is the Global Assimilation of Ionospheric Measurements Full-Physics model (GAIM-FP) that covers the altitude range from 90 to 20,000 km, includes six ion species (NO+, O2+, N2+, O+, H+, He+), is based on the International Geomagnetic Reference Field (IGRF), and allows for interhemispheric flow. The model uses an Ensemble Kalman filter approach and provides the 3-dimensional electron density distribution throughout the ionosphere and information about the physical drivers, including the magnetic meridional wind, neutral composition and electric fields. The geographic zonal and meridional winds were inferred from the magnetic meridional wind based on a decoupling procedure that considers the longitudinal variation of magnetic declination and wind decomposition into zonal harmonics. The separate wind components were used to study their effects on the generation of the anomaly. In addition the production, loss and transport processes were separately analyzed to establish the relative role of the various physical processes that cause the WSA.

Lomidze, L.; Scherliess, L.

2013-01-01

316

Exact Analysis of Single-Phase Thyristor-Controlled Inductive Load in the Presence of Supply Impedance Using Shunt Compensating Capacitor and Harmonic Oscillation Suppressor Inductor.  

National Technical Information Service (NTIS)

The performance of a thyristor-controlled inductive load, fed from a source having significant impedance, was considered, with special reference to its power factor improvement using a shunt capacitor and harmonic oscillation suppressor. To suppress the h...

S. E. Haque W. Shepherd

1981-01-01

317

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

318

A generalized harmonic balance method for EMTP initialization  

SciTech Connect

The harmonic balance method is extended to the steady-state analysis of power system models that include complex nonlinearities and variable topology power electronics equipment as may be user-assembled from basic EMTP-TACS components. In applying the harmonic balance method, these devices are considered as black boxes and isolated from the linear part of the model. A shooting method is used to accelerate the computation of their intermediate time-domain steady-state responses and to solve the harmonic balance equation formulated as a fixed point problem. Numerical tests show that the resulting generalized harmonic balance method is very promising for lightly damped dynamic power system models.

Murere, G.; Lefebvre, S. [Inst. de Recherche d`Hydro-Quebec, Varennes, Quebec (Canada); Do, X.D. [Ecole Polytechnique de Montreal, Quebec (Canada)

1995-07-01

319

Theoretical analysis of the TE mode Cerenkov type second harmonic generation in ion-implanted X-cut lithium niobate channel waveguides  

NASA Astrophysics Data System (ADS)

Optical second harmonic generation (SHG) in the form of Cerenkov radiation from ion-implanted lithium niobate (LiNbO3) channel waveguides is analyzed by directly resolving the wave equations. Useful formula of the SHG efficiency is derived and expressed in terms of waveguide parameters. Numerical examples are plotted for LiNbO3 crystals. The results enable the optimization of waveguide design for efficient second harmonic generation in the Cerenkov configuration.

Du, Guolong; Li, Guiqiu; Zhao, Shengzhi; Li, Xin; Yu, Zhiyuan

2012-06-01

320

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

321

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

322

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

323

Analysis of the physical demands of international rugby union.  

PubMed

The aim of this study was to investigate the physical demands of international rugby union. Five games in the 1989-90 Five Nations Championship were analysed using video-recordings of live television transmissions. When the ball was in open play, the average running pace of players central to the action ranged from 5 to 8 m s-1. This together with scrum, lineout, ruck and maul was classified as high-intensity exercise. The density of work was measured by timing the work:rest ratios (W:RRs) throughout each game. The mean duration of the work periods was 19 s and the most frequent W:RRs were in the range of 1:1 to 1:1.9. On average, a scrum, lineout, ruck or maul occurred every 33 s. The ball was in play for an average of 29 min during a scheduled time of play of 80 min. To complement the time-motion analysis, blood samples were taken from six players throughout a first-class game. The highest measured blood lactate (BLa) concentrations for each individual ranged from 5.8 to 9.8 mM. Running speed, duration, BLa levels, physical confrontation and, most particularly, the density of work as illustrated by the W:RRs indicate that the game places greater demands on anaerobic glycolysis than previously reported. This has implications for the physical conditioning of rugby union players. PMID:1602530

McLean, D A

1992-06-01

324

Harmonic reduction in thyristor converters by harmonic current injection  

Microsoft Academic Search

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

A. Ametani

1976-01-01

325

Reduced-Reference Video Quality Assessment Using Discriminative Local Harmonic Strength With Motion Consideration  

Microsoft Academic Search

This paper presents a reduced-reference objective picture quality measurement tool of compressed video. We have used a discriminative analysis of harmonic strength computed from edge-detected pictures to create harmonics gain and loss information that could be associated with the picture. The harmonics gain\\/loss are derived through the harmonic analysis of the compressed and source pictures to be incorporated in the

Irwan Prasetya Gunawan; Mohammed Ghanbari

2008-01-01

326

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

327

Harmonically excited orbital variations  

SciTech Connect

Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

Morgan, T.

1985-08-06

328

A Harmonic Motion Experiment  

ERIC Educational Resources Information Center

|We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)|

Gluck, P.; Krakower, Zeev

2010-01-01

329

Higher order harmonic detection for exploring nonlinear interactions with nanoscale resolution  

PubMed Central

Nonlinear dynamics underpin a vast array of physical phenomena ranging from interfacial motion to jamming transitions. In many cases, insight into the nonlinear behavior can be gleaned through exploration of higher order harmonics. Here, a method using band excitation scanning probe microscopy (SPM) to investigate higher order harmonics of the electromechanical response, with nanometer scale spatial resolution is presented. The technique is demonstrated by probing the first three harmonics of strain for a Pb(Zr1-xTix)O3 (PZT) ferroelectric capacitor. It is shown that the second order harmonic response is correlated with the first harmonic response, whereas the third harmonic is not. Additionally, measurements of the second harmonic reveal significant deviations from Rayleigh-type models in the form of a much more complicated field dependence than is observed in the spatially averaged data. These results illustrate the versatility of nth order harmonic SPM detection methods in exploring nonlinear phenomena in nanoscale materials.

Vasudevan, R. K.; Okatan, M. Baris; Rajapaksa, I.; Kim, Y.; Marincel, D.; Trolier-McKinstry, S.; Jesse, S.; Valanoor, N.; Kalinin, S. V.

2013-01-01

330

Advantages and limitations of spherical harmonic analyses of geomagnetic data  

NASA Astrophysics Data System (ADS)

The separation of external and internal geomagnetic variation fields using spherical harmonic data analysis is discussed. Examples obtained from geomagnetic data from 40 stations are presented. A large number of high order spherical harmonic terms is needed to approximate satisfactorily the latitudinal field distribution with sharp gradients in the auroral and equatorial regions.

Matsushita, S.

331

Harmonic distortion during the 2010 FIFA World Cup  

Microsoft Academic Search

This paper presents harmonic distortion measurements in several countries taken during live televised matches of the 2010 Soccer World Cup held in South Africa. The paper provides an analysis of the components involved in the increase of total harmonic distortion of current and voltage. The work also compares the latest measurements with previous events and makes some considerations regarding future

P. F. Ribeiro; J. J. A. L. Leitao; M. M. S. Lira; J. R. Macedo Jr; A. L. Z. Grandi; A. Testa; R. Langella; J. F. G. Cobben; N. R. Browne

2011-01-01

332

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

333

Automatic cell segmentation and nuclear-to-cytoplasmic ratio analysis for third harmonic generated microscopy medical images.  

PubMed

Traditional biopsy procedures require invasive tissue removal from a living subject, followed by time-consuming and complicated processes, so noninvasive in vivo virtual biopsy, which possesses the ability to obtain exhaustive tissue images without removing tissues, is highly desired. Some sets of in vivo virtual biopsy images provided by healthy volunteers were processed by the proposed cell segmentation approach, which is based on the watershed-based approach and the concept of convergence index filter for automatic cell segmentation. Experimental results suggest that the proposed algorithm not only reveals high accuracy for cell segmentation but also has dramatic potential for noninvasive analysis of cell nuclear-to-cytoplasmic ratio (NC ratio), which is important in identifying or detecting early symptoms of diseases with abnormal NC ratios, such as skin cancers during clinical diagnosis via medical imaging analysis. PMID:23853298

Lee, Gwo Giun; Lin, Huan-Hsiang; Tsai, Ming-Rung; Chou, Sin-Yo; Lee, Wen-Jeng; Liao, Yi-Hua; Sun, Chi-Kuang; Chen, Chun-Fu

2013-04-01

334

Harmonic analysis of the fluorescence response of bimane adducts of colicin E1 at helices 6, 7, and 10.  

PubMed

The pre-channel state of helices 6, 7, and 10 (Val(447)-Gly(475) and Ile(508)-Ile(522)) of colicin E1 was investigated by a site-directed fluorescence labeling technique. A total of 44 cysteine variants were purified and covalently labeled with monobromobimane fluorescent probe. A variety of fluorescence properties of the bimane fluorophore were measured for both the soluble and membrane-bound states of the channel peptide, including the fluorescence emission maximum, fluorescence anisotropy, and membrane bilayer penetration depth. Using site-directed fluorescence labeling combined with our novel helical periodicity analysis method, the data revealed that helices 6, 7, and 10 are separate amphipathic ?-helices with a calculated periodicity of T = 3.34 ± 0.08 for helix 6, T = 3.56 ± 0.03 for helix 7, and T = 2.99 ± 0.12 for helix 10 in the soluble state. In the membrane-bound state, the helical periodicity was determined to be T = 3.00 ± 0.15 for helix 6, T = 3.68 ± 0.03 for helix 7, and T = 3.47 ± 0.04 for helix 10. Dual fluorescence quencher analysis showed that both helices 6 and 7 adopt a tilted topology that correlates well with the analysis based on the fluorescence anisotropy profile. These data provide further support for the umbrella model of the colicin E1 channel domain. PMID:23264635

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

2012-12-21

335

Does Birth Weight Influence Physical Activity in Youth? A Combined Analysis of Four Studies Using Objectively Measured Physical Activity  

Microsoft Academic Search

Animal models suggest growth restriction in utero leads to lower levels of motor activity. Furthermore, individuals with very low birth weight report lower levels of physical activity as adults. The aim of this study was to examine whether birth weight acts as a biological determinant of physical activity and sedentary time. This study uses combined analysis of three European cohorts

Charlotte L. Ridgway; Søren Brage; Stephen J. Sharp; Kirsten Corder; Kate L. Westgate; Esther M. van Sluijs; Ian M. Goodyer; Pedro C. Hallal; Sigmund A. Anderssen; Luis B. Sardinha; Lars Bo Andersen; Ulf Ekelund; Jacqueline Ho

2011-01-01

336

Harmonic Multiplication Using Resonant Tunneling,  

National Technical Information Service (NTIS)

We propose and demonstrate an odd-harmonic resistive multiplier that exploits the unique current-voltage (I-V) relation of resonant-tunneling diodes. It is shown that efficient odd-harmonic conversion is possible and that even harmonics do not appear beca...

T. C. Sollner E. R. Brown W. D. Goodhue C. A. Correa

1988-01-01

337

Analysis of Radon Decay Data and its Implications for Physics, Geophysics, and Solar Physics.  

NASA Astrophysics Data System (ADS)

We present an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between January 28 2007 and May 10 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis also reveals a number of periodicities, notably at 11.2 year-1 and 12.5 year-1, which we have found in other nuclear-decay data --including data acquired at the Brookhaven National Laboratory and the Physiklisch-Technische Bundesanstalt-- which we attribute to a solar influence. A distinct property of the GSI results is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. We speculate on possible interpretations of this curious result. Solar neutrinos remain our prime suspect as the agent responsible for beta-decay anomalies. These results have implications for physics (that nuclear decay rates are not constant and may be stimulated); for geophysics (that the variability of radon measurements cannot be ascribed entirely to atmospheric and solid-earth processes); and for solar physics (that the Sun contains an inner tachocline, separating a slowly rotating core from the radiative zone, which has properties similar to those of the outer tachocline separating the radiative zone from the convection zone). This work was supported by DOE grant DE-AC-02-76ER071428.

Sturrock, Peter A.; Fischbach, E.; Jenkins, J. H.; Steinitz, G.

2012-05-01

338

Cost and performance analysis of physical security systems  

SciTech Connect

CPA - Cost and Performance Analysis - is a prototype integration of existing PC-based cost and performance analysis tools: ACEIT (Automated Cost Estimating Integrated Tools) and ASSESS (Analytic System and Software for Evaluating Safeguards and Security). ACE is an existing DOD PC-based tool that supports cost analysis over the full life cycle of a system; that is, the cost to procure, operate, maintain and retire the system and all of its components. ASSESS is an existing DOE PC-based tool for analysis of performance of physical protection systems. Through CPA, the cost and performance data are collected into Excel workbooks, making the data readily available to analysts and decision makers in both tabular and graphical formats and at both the system and subsystem levels. The structure of the cost spreadsheets incorporates an activity-based approach to cost estimation. Activity-based costing (ABC) is an accounting philosophy used by industry to trace direct and indirect costs to the products or services of a business unit. By tracing costs through security sensors and procedures and then mapping the contributions of the various sensors and procedures to system effectiveness, the CPA architecture can provide security managers with information critical for both operational and strategic decisions. The architecture, features and applications of the CPA prototype are presented. 5 refs., 3 figs.

Hicks, M.J. [Sandia National Lab., Albuquerque, NM (United States); Yates, D.; Jago, W.H. [Tecolote Research, Inc., Santa Barbara, CA (United States)] [and others

1997-06-01

339

Higher order harmonic detection for exploring nonlinear interactions  

SciTech Connect

Nonlinear dynamics underpin a vast array of physical phenomena ranging from interfacial motion to jamming transitions. In many cases, decoupling the contributions of competing or co-existing mechanisms to the system response can be achieved through investigation of higher order harmonics. Here, a method using band excitation scanning probe microscopy to investigate higher order harmonics of the electromechanical response, with nanometer scale spatial resolution is presented. The utility of the technique is demonstrated by probing the first three harmonics of strain for a well-known system, a model Pb(Zr1-xTix)O3 ferroelectric capacitor. It is shown that the second order harmonic response is correlated with the first harmonic response, whereas the third harmonic is not. Additionally, nanoscale measurements of the second harmonic response with field reveal significant deviations from Rayleigh-type models in the form of a much more complicated field dependence than is observed in the spatially averaged data. These results illustrate the versatility of combining proximal probe techniques with nth harmonic detection methods in exploring and decoupling nonlinear dynamics in a wide variety of nanoscale materials.

Vasudevan, Rama K [ORNL; Okatan, M. B. [University of New South Wales; Rajapaksa, Indrajit [Oak Ridge National Laboratory (ORNL); Kim, Yunseok [ORNL; Marincel, Dan [Materials Science and Engineering, Pennsylvania State University; Trolier-McKinstry, Susan [Pennsylvania State University; Jesse, Stephen [ORNL; Nagarajan, Valanoor [University of New South Wales; Kalinin, Sergei V [ORNL

2013-01-01

340

Combining analysis tools and mathematical modeling to enhance and harmonize food safety and food defense regulatory requirements.  

PubMed

The past decade has seen rapid developments in risk assessment techniques and tools related to food safety and food defense. These advances are beginning to have a significant impact on the decision making processes used by risk managers in both government and industry. Furthermore, the highly complex issues currently facing the management of food safety risks on an international basis are likely to require even more sophisticated assessments. One of the key challenges that must be met to advance the adoption of risk analysis principles is learning how risk managers can best utilize the results of risk assessments as they must take the results of complex stochastic models and adapt the findings to the binary decision criteria that are the basis for legal decisions. This will require a better articulation of key principles of food safety risk management, such as the recently adopted Codex Alimentarius "Principles and Guidelines for the Conduct of Microbial Risk Management." PMID:20149936

Buchanan, Robert L; Appel, Bernd

2010-01-20

341

Driven harmonic oscillator as a quantum simulator for open systems  

SciTech Connect

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

Piilo, Jyrki; Maniscalco, Sabrina [Department of Physics, University of Turku, FI-20014 Turun yliopisto (Finland)

2006-09-15

342

Work-fluctuation theorem for a charged harmonic oscillator  

NASA Astrophysics Data System (ADS)

The solution of the Langevin equation including the inertia term is used to prove the transient work-fluctuation theorem for an electrically charged Brownian harmonic oscillator in an electromagnetic field. The theorem is proved for the physical situation in which the system is driven out of equilibrium by an arbitrary time-dependent dragging of the trap potential minimum. The proof is first given for a harmonic oscillator in the absence of an electromagnetic field, and then is extended to include the case of a charged harmonic oscillator under the action of crossed electric and magnetic fields. The case of a linear motion for the potential minimum is explicitly addressed.

Jiménez-Aquino, J. I.

2011-07-01

343

XII Advanced Computing and Analysis Techniques in Physics Research  

NASA Astrophysics Data System (ADS)

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

Speer, Thomas; Carminati, Federico; Werlen, Monique

344

Ejs Action for the Harmonic Oscillator Model  

NSDL National Science Digital Library

The Ejs Action for the Harmonic Oscillator model displays the trajectory of a simple harmonic oscillator by minimizing the classical action. The simulation displays the endpoints of the motion (t,x) which can be changed by using the text boxes or dragging, and displays the new trajectory as well as calculates the physical trajectory (that minimizes the action). 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 Action for the 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_action.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

2008-08-19

345

TOPICAL REVIEW: Normal mode analysis and applications in biological physics  

NASA Astrophysics Data System (ADS)

Normal mode analysis has become a popular and often used theoretical tool in the study of functional motions in enzymes, viruses, and large protein assemblies. The use of normal modes in the study of these motions is often extremely fruitful since many of the functional motions of large proteins can be described using just a few normal modes which are intimately related to the overall structure of the protein. In this review, we present a broad overview of several popular methods used in the study of normal modes in biological physics including continuum elastic theory, the elastic network model, and a new all-atom method, recently developed, which is capable of computing a subset of the low frequency vibrational modes exactly. After a review of the various methods, we present several examples of applications of normal modes in the study of functional motions, with an emphasis on viral capsids.

Dykeman, Eric C.; Sankey, Otto F.

2010-10-01

346

Statistical Analysis by Statistical Physics Model for the STOCK Markets  

NASA Astrophysics Data System (ADS)

A new stochastic stock price model of stock markets based on the contact process of the statistical physics systems is presented in this paper, where the contact model is a continuous time Markov process, one interpretation of this model is as a model for the spread of an infection. Through this model, the statistical properties of Shanghai Stock Exchange (SSE) and Shenzhen Stock Exchange (SZSE) are studied. In the present paper, the data of SSE Composite Index and the data of SZSE Component Index are analyzed, and the corresponding simulation is made by the computer computation. Further, we investigate the statistical properties, fat-tail phenomena, the power-law distributions, and the long memory of returns for these indices. The techniques of skewness-kurtosis test, Kolmogorov-Smirnov test, and R/S analysis are applied to study the fluctuation characters of the stock price returns.

Wang, Tiansong; Wang, Jun; Fan, Bingli

347

A Utopian View of Space Plasma Physics Data Analysis (Invited)  

NASA Astrophysics Data System (ADS)

In an ideal space physics plasma data environment, I would go to the internet, enter names and types of data sets that I need, find them immediately via a google-like search, download them into a folder, and then use my all-purpose platform-independent software to immediately begin plotting, analyzing, and combining data sets from multiple sources, instruments, and spacecraft without ever writing any software myself or even looking inside the files. In order for this to happen, the data sets would have to be in readily recognizable standardized formats, described in sufficient detail to enable rapid discovery, and accompanied by metadata enabling the software to work. The display and analysis tools would have to include the full range of features needed for data visualization, including the construction of parameters or plots combining observations from multiple sources.

Sibeck, D. G.

2010-12-01

348

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

349

Hypercomplete circular harmonic pyramids  

NASA Astrophysics Data System (ADS)

In this contribution we present a steerable pyramid based on a particular set of complex wavelets named circular harmonic wavelets (CHW). The proposed CHWs set constitutes a generalization of the smoothed edge wavelets introduced by Mallat, consisting of extending the local differential representation of a signal image from the first order to a generic n-th order. The key feature of the proposed representation is the use of complex operators leading to an expansion in series of polar separable complex functions, which are shown to possess the space-scale representability of the wavelets. The resulting tool is highly redundant, and for this reason is called hypercomplete circular harmonic pyramid (HCHP), but presents some interesting aspects in terms of flexibility, being suited for many image processing applications. In the present contribution the main theoretical aspects of the HCHPs are discussed along with some introductory applications.

Jacovitti, Giovanni; Manca, A.; Neri, Alessandro

1996-10-01

350

Assessment of intramural blood flow and neurogenic control in intact and hypertrophic urinary bladder with harmonic analysis of bioimpedance in rats.  

PubMed

High-resolution impedancometry and harmonic (Fourier) analysis of variable component of bioimpedance revealed rhythmic oscillations of urinary bladder bioimpedance at the Mayer wave, respiration, and heartbeat frequencies. The power values of the corresponding Mayer, respiratory, and cardiac peaks were calculated to assess circulation in the urinary bladder wall and its autonomic nervous control at various stages of infusion cystometry in intact rats and in the rats with preliminary formed infravesical obstruction (IVO). In intact rats, filling of the bladder with physiological saline diminished the power of the first (fundamental) cardiac peak attesting to a decrease of the blood flow in the bladder wall. Simultaneously, the power of low-frequency Mayer peak reflecting sympathetic activity increased, while the power of respiratory peak decreased supposedly reflecting abatement of the parasympathetic influences. Bladder voiding was accompanied by a decrease of Mayer peak and increase of the respiratory one. Prior to infusion cystometry, the intravesical pressure in IVO rats was elevated while the power of fundamental cardiac peak was below the control value. Filling the bladder in these rats was accompanied by further decrease of the cardiac peak reflecting still greater drop in blood supply. In control rats, voiding the bladder normalized the vesical circulation assessed by the cardiac peak, while in IVO rats this peak remained decreased. The reciprocal changes of Mayer and respiratory peaks observed during infusion cystometry in the norm were replaced by unidirectional decrease in the power of both peaks in IVO rats, which probably attest to disturbance of autonomic nervous control in the hypertrophic urinary bladder in these rats. PMID:22977838

Kirpatovsky, V I; Mudraya, I S; Revenko, S V; Nesterov, A V; Gavrilov, I Yu; Khromov, R A; Bablumyan, A Yu

2012-08-01

351

Simple Harmonic Motion - Example  

NSDL National Science Digital Library

This website contains a detailed development and comparison of a classical and a quantum mechanical description of motion in a simple harmonic potential "spring force", complete with figures. This example is a part of a larger collection of examples in which the classical and quantum mechanical descriptions are compared. (Note that there are thirteen pages, and that the user must use the navigation buttons at the bottom of the page)

Kirkman, Tom

2005-07-26

352

Well-posedness and accuracy of harmonic linearization for Lur’e systems  

Microsoft Academic Search

In this paper we deal with the performance analysis of harmonically forced nonlinear systems of Lur'e type. We use harmonic linearization to obtain a linear approximation of the nonlinear system, and provide a frequency domain condition that guarantees a unique positive real solution to the harmonic balance equation for a certain class of nonlinearities. Furthermore, we provide an estimate on

Roel van den Berg; Alexander Pogromsky; Koos Rooda

2007-01-01

353

DSP and GPS-based synchronized measurement system of harmonics in wide-area distribution system  

Microsoft Academic Search

With the recent progress in power electronics devices, harmonic pollution in the power system becomes a significant problem. Therefore, a great deal of attention has been paid to harmonic regulations and suppression technologies. As the utility power distribution system becomes broader and more complex, advanced harmonic measurement and analysis technologies are required. This paper presents the advanced measurement system of

Hiroyuki Ukai; Koichi Nakamura; Nobuyuki Matsui

2003-01-01

354

Atomic high-order harmonic generation from a circularly polarized laser pulse  

NASA Astrophysics Data System (ADS)

We demonstrate theoretically that the high-order harmonic of an atom can be generated by a circularly polarized laser pulse. The harmonic spectrum shows a clear cutoff with an energy Ip + 2Up. In particular, the high-order harmonic generation comes from the multiple recombination of the ionized electron with non-zero initial velocity. These results are verified by the classical model theory and the time-frequency analysis of a harmonic spectrum.

Guo, Fu-Ming; Chen, Gao; Chen, Ji-Gen; Li, Su-Yu; Yang, Yu-Jun

2013-02-01

355

Interference effects in two-color high-order harmonic generation  

SciTech Connect

We study high-order harmonic generation in argon driven by an intense 800 nm laser field and a small fraction of its second harmonic. The intensity and divergence of the emitted even and odd harmonics are strongly modulated as a function of the relative delay between the two fields. We provide a detailed analysis of the underlying interference effects. The interference changes drastically when approaching the cutoff region due to a switch of the dominant trajectory responsible for harmonic generation.

He, X.; Dahlstroem, J. M.; Rakowski, R.; Persson, A.; Mauritsson, J.; L'Huillier, A. [Department of Physics, Lund University, P. O. Box 118, SE-221 00 Lund (Sweden); Heyl, C. M. [Department of Physics, Lund University, P. O. Box 118, SE-221 00 Lund (Sweden); Department of Physics, University of Marburg, Marburg (Germany)

2010-09-15

356

A HEMT harmonic oscillator stabilized by an X-band dielectric resonator  

Microsoft Academic Search

A simple design method for harmonic oscillators using HEMT (high-electron-mobility-transistor) devices is presented. The method employs nonlinear analysis to derive the harmonic components of the drain current of a low-frequency transistor model. The resulting harmonic components are used to linearize a high-frequency model and to synthesize the microwave circuit. A second-harmonic oscillator that uses an X-band dielectric resonator and a

R. Tupynamba; Edmar Camargo; Fatha S. Correra

1991-01-01

357

A Improved Transmission System Harmonic Modeling Technique.  

NASA Astrophysics Data System (ADS)

The development of a comprehensive approach to the modeling of electric power transmission systems at harmonic frequencies is presented. For harmonic analysis it is not practically possible to model a large transmission system with its neighboring interconnected systems in detail due to computer time and memory limitations. A large number of components of a large system also makes switching studies a recognized problem with respect to the desired accuracy, and required engineering and computer time. Current methods depend on the trial and error approach or the individual analyst's knowledge of the system, which are imprecise and expensive to develop at harmonic frequencies. The approach to solve this problem involves the development of a formal method for dividing large-scale transmission systems into a main study system and a group of external systems. Then, using an efficient and appropriate method of adjoint network sensitivity analysis, the size of the system model is reduced, keeping the same frequency characteristics as that of the original system. This reduction in model size in turn accommodates larger transmission system size and increases the accuracy and computational efficiency. An efficient and accurate method is also presented that determines the relative importance of external system equivalents on the harmonic impedance of a transmission network. The bilinear theorem provides an economical method of determining the appropriate locations for simplification of external systems. Using this technique, the system model error bounds can be fixed and the high error range of the external system equivalent impedance can be reduced. For filter designs, the most important issue of computing harmonic impedance boundaries is improved by using an efficient adjoint network sensitivity analysis. Using this sensitivity analysis an order of critical components is developed. The number of outage contingencies to be analyzed is reduced by a large factor which considerably reduces the engineering time and increases dependability. Two transmission systems have been studied to demonstrate the proposed methods. This work will provide transmission system planners and designers an efficient and economical tool of known accuracy for the analysis of harmonic propagation, switching studies and design of harmonic filters.

Akram, Muhammad Fayyaz

1994-01-01

358

Numerical analysis of nonequilibrium hypersonic flow: A study of influence of physical model  

NASA Astrophysics Data System (ADS)

The influence of physical models on the hypersonic flow field in the shock layer around an axisymmetric body is studied. Thermochemical nonequilibrium effects are considered by using Park's two-temperature model. Two important physical effects are modeled; vibrational-translational relaxation and vibrational energy removal due to molecular dissociation. The vibrational relaxation times are evaluated both by the Landau-Teller theory and by the SSH (Schwartz-Slawsky-Herzfeld) theory (with the harmonic-oscillator approximation) and numerical results around a sphere are compared. The influence of the vibrational energy removal is studied parametrically by changing the average removed vibrational energy due to dissociation. It becomes clear that both effects have a considerable influence on the vibrational-electronic temperature distribution, and that the shock location on the stagnation streamline may change about 1 percent of the radius. These results indicate the need for a more sophisticated model for vibrational energy removal due to molecular dissociation.

Kurotaki, Takuji

1992-12-01

359

Data intensive high energy physics analysis in a distributed cloud  

NASA Astrophysics Data System (ADS)

We show that distributed Infrastructure-as-a-Service (IaaS) compute clouds can be effectively used for the analysis of high energy physics data. We have designed a distributed cloud system that works with any application using large input data sets requiring a high throughput computing environment. The system uses IaaS-enabled science and commercial clusters in Canada and the United States. We describe the process in which a user prepares an analysis virtual machine (VM) and submits batch jobs to a central scheduler. The system boots the user-specific VM on one of the IaaS clouds, runs the jobs and returns the output to the user. The user application accesses a central database for calibration data during the execution of the application. Similarly, the data is located in a central location and streamed by the running application. The system can easily run one hundred simultaneous jobs in an efficient manner and should scale to many hundreds and possibly thousands of user jobs.

Charbonneau, A.; Agarwal, A.; Anderson, M.; Armstrong, P.; Fransham, K.; Gable, I.; Harris, D.; Impey, R.; Leavett-Brown, C.; Paterson, M.; Podaima, W.; Sobie, R. J.; Vliet, M.

2012-02-01

360

On a new harmonic selection technique for harmonic balance method  

NASA Astrophysics Data System (ADS)

This paper is intended to present a new harmonic selection technique when solving nonlinear dynamic systems with the harmonic balance method. This technique belongs to the class of method called the adaptive harmonic balance method (AHBM). The harmonic selection is based on the use of a tangent predictor and relies on a stepwise regression procedure that allows for a dynamic management of the number of selected harmonics via an addition or removal procedure. The efficiency of this method relative to the classical harmonic balance method (HBM) is then evaluated through examples; this later step will indicate that AHBM can significantly reduce the number of variables, thus leading to computational time savings without deteriorating solution quality.

Grolet, Aurélien; Thouverez, Fabrice

2012-07-01

361

Tangibles for learning: a representational analysis of physical manipulation  

Microsoft Academic Search

Manipulatives—physical learning materials such as cubes or tiles—are prevalent in educational settings across cultures and\\u000a have generated substantial research into how actions with physical objects may support children’s learning. The ability to\\u000a integrate digital technology into physical objects—so-called ‘digital manipulatives’—has generated excitement over the potential\\u000a to create new educational materials. However, without a clear understanding of how actions with physical

Andrew ManchesClaire O'Malley; Claire O’Malley

362

Analysis of the harmonic composition of a phase current curve for estimating the power distribution in the crucible of an electric ore smelting furnace  

NASA Astrophysics Data System (ADS)

A model is proposed for the phase of an electric ore smelting furnace with a hidden arc, and its implementation with Simulink is presented. The possibility of estimating the powers releasing in the arc and the charge from the harmonic composition of the phase current of the furnace is shown.

Rubtsov, V. P.; Elizarov, V. A.

2012-06-01

363

Analysis of a System of Two Weakly Non-Linear Coupled Harmonic Oscillators Arising from the Field of Wind-Induced Vibrations.  

National Technical Information Service (NTIS)

In the paper a system of two weakly non-linear coupled harmonic oscillators is considered. For the lower order frequency ratios the influence of the coupling terms on the occurrence and (local) stability of periodic motions is studied, as well as the glob...

C. G. A. van der Beek

1989-01-01

364

An Analysis of Secondary Student Preferences towards Physical Education.  

ERIC Educational Resources Information Center

|Reports a study that examined secondary students' preferences on grading procedures, activity offerings, academic physical education, hygiene, dress, extracurricular sports participation, and objectives in physical education. Surveys of 958 students indicated that, in many instances, student preferences were directly opposite to what physical…

Strand, Brad; Scantling, Ed

1994-01-01

365

Local dynamics in high-order-harmonic generation using Bohmian trajectories  

NASA Astrophysics Data System (ADS)

We investigate high-order-harmonic generation from a Bohmian-mechanical perspective and find that the innermost part of the core, represented by a single Bohmian trajectory, leads to the main contributions to the high-harmonic spectra. Using time-frequency analysis, we associate this central Bohmian trajectory to an ensemble of unbound classical trajectories leaving and returning to the core, in agreement with the three-step model. In the Bohmian scenario, this physical picture builds up nonlocally near the core via the quantum mechanical phase of the wave function. This implies that the flow of the wave function far from the core alters the central Bohmian trajectory. We also show how this phase degrades in time for the peripheral Bohmian trajectories as they leave the core region.

Wu, J.; Augstein, B. B.; Figueira de Morisson Faria, C.

2013-08-01

366

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

367

The Not-So-Simple Harmonic Oscillator  

NASA Astrophysics Data System (ADS)

The study of simple harmonic oscillators is a staple of physics courses and laboratories at the introductory level. We consider a system consisting of a vertical spring with a suspended mass. One typical laboratory experiment is the demonstration of Hooke's law using static measurements of extension vs. force. Another is the demonstration of simple harmonic motion using dynamic measurements of T^2 vs. the effective system mass. Theoretical analyses predict linear relationships for both experiments. The slopes of the best-fit lines are g/k for Hooke's law, where g is the gravitational field strength and k is the force constant, and (42?)/k for simple harmonic motion. It would appear that these results provide a straightforward way of calculating a value for g. The work done for this senior capstone project strongly suggests that it may not be feasible to determine a reliable value of g using these two experiments alone. Some ideas for alternative formulations of these experiments at the level of intermediate and advanced physics laboratories will be suggested. An additional set of experiments involving magnetic damping of the same system was performed with excellent results. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.OSS07.P1.16

Sears, William; Whitmore Hancock, G.

2007-05-01

368

Monte Carlo harmonic-balance and drift-diffusion harmonic-balance analyses of 100-600 GHz Schottky barrier varactor frequency multipliers  

Microsoft Academic Search

To date, high frequency multipliers have been designed and analyzed using harmonic-balance codes incorporating equivalent circuit models for the diodes. These codes, however, are unable to accurately predict circuit performance at frequencies above 100 GHz and do not allow a means for studying the physics of electron transport. In order to analyze these high frequency Schottky doublers, a novel harmonic-balance

R. E. Lipsey; S. H. Jones; J. R. Jones; T. W. Crowe; L. F. Horvath; U. V. Bhapkar; R. J. Mattauch

1997-01-01

369

Preliminary rock physics analysis on Grosmont carbonate formation, Alberta, Canada  

NASA Astrophysics Data System (ADS)

Grosmont formation in Canada is a bitumen-saturated carbonate reservoir and draw increasing attention as a possible future unconventional oil field. However, the characterization of the formation is not easy due to high geological complexity. In this paper, we report our preliminary results of rock physics modeling effort using log data from seven wells in the T85R19W4 township, Alberta, Canada. Since the acoustic and shear velocity data are not very common, we use three logging properties: gamma ray; neutron-density porosity; and resistivity. The bitumen saturation is obtained from core measurement data. From the preliminary analysis, Grosmont formation can be divided into two groups by resistivity and porosity. The lower group matches with Grosmont A and B from previous studies and upper group with Grosmont C and D. The lower group mainly consists of limestone with different clay contents. The upper group was under dolomitization and karstification during Mesozoic, and is composed of fractured dolomite and karst breccia. The two groups can be divided by 15% porosity and 100 ohm-m resistivity values. The upper group has higher porosity and higher resistivity, which indicates high bitumen saturation and better reservoir quality. In porosity-resistivity domain, some wells shows typical trend; resistivity increases as porosity decrease; however, wells from the north-eastern part does not show any consistent trends. We believe that north-eastern part of our study area has more dolomitization and karstification, thus higher heterogeneity. We report basic trends for porosity vs. resistivity using Hashin-Shtrikman bounds for upper and lower group at each well. We also plan to obtain velocity data and perform quantitative analysis on porosity-velocity relations and velocity sensitivity to bitumen saturation. Acknowledgement: This research was funded by Energy Efficiency and Resources Program of KETEP (Korea Institute of Energy Technology Evaluation and Planning), Grant No. 2008-R-ER-11-P-04-0-30-2008.

Hu, D.; Keehm, Y.

2009-12-01

370

Harmonic generation in optical fibers  

SciTech Connect

This patent describes an apparatus for providing second harmonic generated radiation. It comprises: an optical fiber disposed in a laser cavity, the optical fiber having a substantially single-mode core which is doped with an active laser material, the laser material being self-organizable to produce radiation by second harmonic generation, the laser material further being substantially transparent to the second harmonic generated radiation; and means for pumping the core of the optical fiber to produce laser radiation therein and the laser cavity further comprising means for extracting at least a portion of the second harmonic generated radiation.

Sherborn, H.P.

1990-05-01

371

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.  

SciTech Connect

Detailed reactor physics and safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron and photon transport calculations were performed with the MCNP code to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim safety arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim safety arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model that includes the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the core power transient is terminated by a reactor trip at 26 MW. The calculations show that both the peak reactor power and the excursion energy depend on the negative reactivity insertion from reactor trip. In one of the loss-of-flow accidents offsite electrical power is assumed lost to the three operating primary pumps. A slightly delayed reactor scram is initiated as a result of primary flow coast down. The RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur, because of the momentum of the coolant flowing through the fuel channels and the negative scram reactivity insertion. For both the primary pump seizure and inadvertent throttling of a flow control valve, the RELAP5 analyses indicate that the reduction in power following the trip is sufficient to ensure that there is adequate margin to CHF and that the fuel cladding does not fail. The analysis of the loss-of-flow accident in the extremely unlikely case where both shutdown pumps fail, shows that the cooling provided by the D{sub 2}O is sufficient to ensure the cladding does not fail. The power distributions were examined for a set of fuel misloadings in which a fresh fuel element is moved from a peripheral low-reactivity location to a central high-reactivity location. The calculations show that there is adequate margin to CHF and the cladding does not fail. An additional analysis was performed to simulate the operation at low power (500 kW) without forced flow cooling. The result indicates that natural convection cooling is adequate for operation of the NBSR at a power level of 500 kW.

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

2004-03-31

372

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

373

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

374

Analysis of effects of macroscopic propagation and multiple molecular orbitals on the minimum in high-order harmonic generation of aligned CO{sub 2}  

SciTech Connect

We report theoretical calculations of the effect of the multiple-orbital contribution in high-order harmonic generation (HHG) of aligned CO{sub 2} with the inclusion of macroscopic propagation of harmonic fields in the medium. Our results show very good agreement with recent experiments for the dynamics of the minimum in HHG spectra as laser intensity or alignment angle changes. Calculations are carried out to check how the position of the minimum in HHG spectra depends on the degrees of molecular alignment, laser-focusing conditions, and the effects of alignment-dependent ionization rates of the different molecular orbitals. These analyses help to explain why the minima observed in different experiments may vary.

Jin, Cheng; Le, Anh-Thu; Lin, C. D. [J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506-2604 (United States)

2011-05-15

375

Harmonic generation at high intensities  

SciTech Connect

Atomic electrons subject to intense laser fields can absorb many photons, leading either to multiphoton ionization or the emission of a single, energetic photon which can be a high multiple of the laser frequency. The latter process, high-order harmonic generation, has been observed experimentally using a range of laser wavelengths and intensities over the past several years. Harmonic generation spectra have a generic form: a steep decline for the low order harmonics, followed by a plateau extending to high harmonic order, and finally an abrupt cutoff beyond which no harmonics are discernible. During the plateau the harmonic production is a very weak function of the process order. Harmonic generation is a promising source of coherent, tunable radiation in the XUV to soft X-ray range which could have a variety of scientific and possibly technological applications. Its conversion from an interesting multiphoton phenomenon to a useful laboratory radiation source requires a complete understanding of both its microscopic and macroscopic aspects. We present some recent results on the response of single atoms at intensities relevant to the short pulse experiments. The calculations employ time-dependent methods, which we briefly review in the next section. Following that we discuss the behavior of the harmonics as a function of laser intensity. Two features are notable: the slow scaling of the harmonic intensities with laser intensity, and the rapid variation in the phase of the individual harmonics with respect to harmonic order. We then give a simple empirical formula that predicts the extent of the plateau for a given ionization potential, wavelength and intensity.

Schafer, K.J.; Krause, J.L.; Kulander, K.C.

1993-06-01

376

Orbit determination and analysis for Cosmos 58 at 15th-order resonance, to evaluate geopotential harmonics of order 15 and 30  

Microsoft Academic Search

The orbital parameters of Cosmos 58 have been determined at 65 epochs from some 4500 observations, between March 1982 and September 1983, using the RAE orbit refinement program, PROP. During this time, the satellite passed slowly through 15th-order resonance, and the orbital inclination and eccentricity have been analyzed. Six lumped 15th-order geopotential harmonic coefficients have been evaluated, with an accuracy

Doreen M. C. Walker

1986-01-01

377

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

378

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

379

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.  

SciTech Connect

Detailed reactor physics and safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional MCNP Monte Carlo neutron and photon transport calculations were performed to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model including the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the core power transient is terminated by a reactor trip at 30 MW. The calculations show that both the peak reactor power and the excursion energy depend on the negative reactivity insertion from reactor trip. Two cases were considered for loss of electrical power. In the first case offsite power is lost, resulting in an immediate scram caused by loss of power to the control rod system. In the second case power is lost to only the three operating primary pumps, resulting in a slightly delayed scram when loss-of-flow is detected as the pumps coast down. In both instances, RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur, because of the momentum of the coolant flowing through the fuel channels and the negative scram reactivity insertion. For both the primary pump seizure and inadvertent throttling of a flow control valve, the RELAP5 analyses indicate that the reduction in power following the trip is sufficient to ensure that there is adequate margin to CHF and the fuel cladding does not fail. The analysis of the loss-of-flow accident in the extremely unlikely case where both shutdown pumps fail shows that the cooling provided by the D{sub 2}O is sufficient to ensure the cladding does not fail. The power distributions were examined for a set of fuel misloadings in which a fresh fuel element is moved from a peripheral low-reactivity location to a central high-reactivity location. The calculations show that there is adequate margin to CHF and the cladding does not fail.

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

2003-08-26

380

Harmonics from compact fluorescent lamps  

Microsoft Academic Search

The measured performance of compact fluorescent lamps (CFLs) and some rectified incandescent lamps, which can cause considerable harmonic distortion of the input power, is discussed. These include both the electronically and magnetically ballasted CFLs with poor power factors and\\/or high harmonics. Using the model of a building's electrical load, it is shown that there is little cause for concern for

R. R. Verderber; O. C. Morse; W. R. Alling

1993-01-01

381

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

382

A split-frequency harmonic balance method for nonlinear oscillators with multi-harmonic forcing  

NASA Astrophysics Data System (ADS)

A new harmonic balance method (HBM) is presented for accurately computing the periodic responses of a nonlinear sdof oscillator with multi-harmonic forcing and non-expansible nonlinearities. The presence of multi-harmonic forcing requires a large number of solution harmonics with a substantial increase in computational demand for either the conventional or the incremental HBM. In this method, the oscillator equation-error is first defined in terms of two functions (originally proposed for obtaining free-vibration periods in: R.E. Mickens, Iteration procedure for determining approximate solutions to nonlinear oscillator equations, Journal of Sound and Vibration 116 (1987) 185 187; and more recently: R.E. Mickens, A Generalised iteration procedure for calculating approximations to periodic solutions of “truly nonlinear oscillations”, Journal of Sound and Vibration 287 (2005) 1045 1051). A Fourier series solution is assumed, in which the total number of harmonics is fixed by the chosen discrete-time interval—this series is split into two partial sums nominally associated with either low-frequency or high-frequency harmonics. By exploiting a convergence property of the equation-error functions, the total solution is obtained in a new iterative scheme in which the low-frequency components are computed via a conventional HBM using a small number of algebraic equations, whereas the high frequency components are obtained in a separate step by updating. By gradually increasing the number of harmonics in the low-frequency group, the equation-error can be progressively reduced. Efficient use is made of FFT-based algebraic equation generation which allows an important class of non-expansible nonlinearities to be handled. The proposed method is tested on a Duffing-type oscillator, and an oscillator with a non-expansible 7th power stiffness term, where in both cases up to 24 component multi-harmonic forcing is applied. As a comparison, a conventional HBM is also used on the Duffing model in which the algebraic equations are generated in symbolic form to totally avoid errors from entering the formulation through complicated expansion of the cubic stiffness term (as in: I. Senjanovi?, Harmonic analysis of nonlinear oscillations of cubic dynamical systems, Journal of Ship Research 38 (3) (1994) 225 238; and in: A. Raghothama, S. Narayanan, Periodic response and chaos in nonlinear systems with parametric excitation and time delay, Nonlinear dynamics 27 (2002) 341 365). The paper shows that in obtaining period-1 solutions, the computational accuracy and efficiency of the proposed method is very good.

Dunne, J. F.; Hayward, P.

2006-08-01

383

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.

384

Nonlinear cyclotron harmonic absorption  

SciTech Connect

Nonlinear oscillations of particle's energy occur when a particle stays in a resonance zone. In this work, we found that collisionless heating of particles occurs when they pass the microwave beam at first, second, and third harmonic resonances. It is found that the net energy gain of particles from the microwaves is inversely proportional to the wave frequency. It is also found that the net energy gain is dependent on the microwave beam width. The energy gain of particles from a single pass through a resonance zone has been formulated analytically. A numerical calculation has been performed and the results are in good agreement with the analytic calculation. Both analytic and numerical calculations show a strong frequency dependence and a beam width dependence of nonlinear cyclotron resonance heating.

Seol, Jae Chun [National Fusion Research Institute, Yuseong, Daejeon 555-333 (Korea, Republic of); Hegna, C. C.; Callen, J. D. [Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706-1609 (United States)

2009-05-15

385

The LCG PI project: using interfaces for physics data analysis  

Microsoft Academic Search

In the context of the LHC Computing Grid (LCG) project, the Applications Area develops and maintains that part of the physics applications software and associated infrastructure that is shared among the LHC experiments. The \\

V. Innocente; H. C. Lee; L. Moneta; A. Pfeiffer; W. L. Ueng

2004-01-01

386

The LCG PI project: using interfaces for physics data analysis  

Microsoft Academic Search

In the context of the LHC computing grid (LCG) project, the applications area develops and maintains that part of the physics applications software and associated infrastructure that is shared among the LHC experiments. The \\

A. Pfeiffer; L. Moneta; V. Innocente; H. C. Lee; W. L. Ueng

2005-01-01

387

Geometry Description Markup Language for Physics Simulation and Analysis Applications  

Microsoft Academic Search

The Geometry Description Markup Language (GDML) is a specialized XML-based language designed as an application-independent persistent format for describing the geometries of detectors associated with physics measurements. It serves to implement \\

Radovan Chytracek; Jeremy McCormick; Witold Pokorski; Giovanni Santin

2006-01-01

388

Multi-physics analysis of laser solid freeform fabrication  

NASA Astrophysics Data System (ADS)

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

Alimardani, Masoud

389

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

390

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

391

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

392

Collective flow and correlation with higher harmonic event planes  

NASA Astrophysics Data System (ADS)

Azimuthal event anisotropy and particle correlation have been used to analyze the collectivity of the system created in the high-energy heavy-ion collisions in order to study the properties of Quark Gluon Plasma (QGP). Higher harmonic event anisotropy is recently recognized to carry the information of initial participant geometrical fluctuation because of the finite number of participating nucleons in heavy-ion collisions. The system response after the collective expansion can be observed as higher harmonic event anisotropy, the n-th harmonic order dependence can be used to further constrain the hydro-dynamical properties of the system. The multi-particle azimuthal correlation with respect to the higher harmonic event plane can be used as a tool to understand the origin of the higher harmonic event anisotropy and its relation to the medium response from the jet-quenching as soft-hard interplay. Recent results on the higher harmonic event anisotropy measurements and an attempt of two-particle correlation analysis with respect to the higher harmonic event planes are discussed.

Esumi, ShinIchi

2012-12-01

393

Global spherical harmonic computation by two-dimensional Fourier methods  

Microsoft Academic Search

A method is presented for performing global spherical harmonic computation by two-dimensional Fourier transformations. The method goes back to old literature (Schuster 1902) and tackles the problem of non-orthogonality of Legendre-functions, when discretized on an equi-angular grid. Both analysis and synthesis relations are presented, which link the spherical harmonic spectrum to a two-dimensional Fourier spectrum. As an alternative, certain functions

Nico Sneeuw; Richard Bun

1996-01-01

394

A generalized harmonic balance method for EMTP initialization  

Microsoft Academic Search

The harmonic balance method is extended to the steady-state analysis of power system models that include complex nonlinearities and variable topology power electronics equipment as may be user-assembled from basic EMTP-TACS components. In applying the harmonic balance method, these devices are considered as black boxes and isolated from the linear part of the model. A shooting method is used to

G. Murere; S. Lefebvre; X. D. Do

1995-01-01

395

Implementation of a new harmonic initialization method in the EMTP  

SciTech Connect

Nonlinear branches, such as saturable reactors, can generate harmonics and consequently increase the EMTP time-domain simulation time before the actual distorted steady-state is reached. This is an important initialization problem for transient analysis studies performed in steady-state operating conditions. This paper presents the implementation of a new method in the EMTP for initializing time-domain simulations. It is based on frequency domain steady-state calculations including harmonics from nonlinear branch functions.

Lombard, X.; Kieny, C. [Electricite de France, Clamart (France). Direction des Etudes et Recherches; Mahseredjian, J.; Lefebvre, S. [Inst. de Recherche d`Hydro-Quebec, Varennes, Quebec (Canada)

1995-07-01

396

Teaching Physics from a Reduced Gravity Environment  

Microsoft Academic Search

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

Raymond D. Benge; C. Young; S. Davis; A. Worley; L. Smith; A. Gell

2010-01-01

397

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

398

Evaluation of harmonic impacts from compact fluorescent lights on distribution systems  

SciTech Connect

Compact fluorescent lamps (CFLs) have the potential to increase the overall harmonic distortion levels on distribution systems. Measurements of the harmonic characteristics of different types of CFLs are presented and the possible impacts on a distribution system are analyzed. The analysis uses a combination of EMTP simulations and conventional harmonic analysis simulations to predict the distribution system distortion levels as a function of system characteristics, the CFL characteristics, and the CFL penetration level.

Dwyer, R.; Khan, A.K.; McGranaghan, M.; Tang, L.; McCluskey, R.K.; Sung, R.; Houy, T.

1995-11-01

399

Volumetric Colon Wall Unfolding Using Harmonic Differentials  

PubMed Central

Volumetric colon wall unfolding is a novel method for virtual colon analysis and visualization with valuable applications in virtual colonoscopy (VC) and computer-aided detection (CAD) systems. A volumetrically unfolded colon enables doctors to visualize the entire colon structure without occlusions due to haustral folds, and is critical for performing efficient and accurate texture analysis on the volumetric colon wall. Though conventional colon surface flattening has been employed for these uses, volumetric colon unfolding offers the advantages of providing the needed quantities of information with needed accuracy. This work presents an efficient and effective volumetric colon unfolding method based on harmonic differentials. The colon volumes are reconstructed from CT images and are represented as tetrahedral meshes. Three harmonic 1-forms, which are linearly independent everywhere, are computed on the tetrahedral mesh. Through integration of the harmonic 1-forms, the colon volume is mapped periodically to a canonical cuboid. The method presented is automatic, simple, and practical. Experimental results are reported to show the performance of the algorithm on real medical datasets. Though applied here specifically to the colon, the method is general and can be generalized for other volumes.

Zeng, Wei; Marino, Joseph; Kaufman, Arie; Gu, Xianfeng David

2011-01-01

400

High-order harmonic generation in alkanes  

SciTech Connect

We have investigated the process of high-order harmonic generation in light alkanes by using femtosecond laser pulses. We show the experimental results cannot be matched by a model that assumes a single active electron only in a hydrogenic s orbital. Clear evidences are shown of the important role played by the p-like character originating from the covalent C-H bond. By constructing a suitable mixture of s-type and p-type atomic wave functions, an excellent agreement between measurements in methane and simulations is found, thus confirming the validity of the developed method as a general tool for the analysis of high-order harmonic generation in complex molecules.

Altucci, C.; Velotta, R.; Heesel, E.; Springate, E.; Marangos, J. P.; Vozzi, C.; Benedetti, E.; Calegari, F.; Sansone, G.; Stagira, S.; Nisoli, M.; Tosa, V. [CNISM-Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Naples (Italy); Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); National Laboratory for Ultrafast and Ultraintense Optical Science, CNR, INFM, Department of Physics, Politecnico, Milan (Italy); NIRDINT, Donath Street 71-103, 400293 Cluj-Napoca (Romania)

2006-04-15

401

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

402

Review of physics methodology of ATR safety analysis.  

National Technical Information Service (NTIS)

At the request of EG&G Idaho, the Pacific Northwest Laboratory (PNL) performed a brief review of the physics methods employed in the safety analyses for the Advanced Test Reactor. PNL determined that the general approach used by EG&G was sound. Comparison...

W. W. Little S. W. Heaberlin

1991-01-01

403

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

404

Noncommutative analysis and quantum physics I. Quantities, ensembles and states  

Microsoft Academic Search

A unified conceptual foundation of classical and quantum physics is given, free of undefined terms. Ensembles are defined by extending the `probability via expectation' approach of Whittle to noncommuting quantities. This approach carries no connotations of unlimited repeatability; hence it can be applied to unique systems such as the universe. Precise concepts and traditional results about complementarity, uncertainty and nonlocality

Arnold Neumaier

2000-01-01

405

Behavioral Analysis of Physical Security Job Analyses. Volume 1.  

National Technical Information Service (NTIS)

The purpose of this research is to identify ways to reduce attrition of enlisted and junior officer personnel assigned to physical security positions upon graduation from the U.S. Army Military Police School (USAMPS) and at the same time to improve perfor...

F. Wolfer P. S. Abbott R. Orth

1980-01-01

406

Analysis of the physical demands of international rugby union  

Microsoft Academic Search

The aim of this study was to investigate the physical demands of international rugby union. Five games in the 1989–90 Five Nations Championship were analysed using video?recordings of live television transmissions. When the ball was in open play, the average running pace of players central to the action ranged from 5 to 8 m s. This together with scrum, lineout,

D. A. McLean

1992-01-01

407

A quantitative analysis of physics textbooks for scientific literacy themes  

NASA Astrophysics Data System (ADS)

The purpose of this study was to examine the content of textbooks used in the Victorian Physics course between 1967 and 1997 for curriculum balance and emphasis on the following aspects of scientific literacy: (a) science as a body of knowledge, (b) science as a way of investigating, (c) science as a way of thinking, and (d) the interaction between science, technology and society. These themes were chosen because they are reflected in the aims of the current Victorian Certificate of Education (VCE) Physics course. The textbook is an important teaching aid in senior school physics in Victoria since it conveys some of the information that students receive and influences how students perceive the subject. The majority of the textbooks analysed stress science as a body of knowledge, place some emphasis on science as a way of investigating, and have little emphasis on science as a way of thinking. Texts produced for the new VCE Physics course (post 1990) were found to place more emphasis on the theme science, technology and society than texts produced prior to 1990.

Wilkinson, John

1999-09-01

408

The Use of Cluster Analysis in Physical Data Base Design  

Microsoft Academic Search

The physical structure and relative placement of information elements within a data base is critical for the efficient design of a computerized information system which is shared by a community of users. Traditionally the selection among alternative structural designs has been handled largely via heuristics. Recent research has shown that a number of significant design problems can be stated mathematically

Jeffrey A. Hoffer; Dennis G. Severance

1975-01-01

409

Physical demands analysis of occupational tasks in neighborhood pubs  

Microsoft Academic Search

This paper describes a case study of a neighborhood pub in British Columbia, Canada. This case study is an examination of three common pub occupations—bartending, waitressing and cooking (n=17). The aims of this study are to determine the biomechanical loads of job tasks identified as physically demanding for the three occupations analyzed, to assess the potential risk of musculoskeletal injury

Troy Jones; Megan Strickfaden; Shrawan Kumar

2005-01-01

410

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

411

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

412

Cost and performance analysis of physical security systems  

Microsoft Academic Search

CPA - Cost and Performance Analysis - is a prototype integration of existing PC-based cost and performance analysis tools: ACEIT (Automated Cost Estimating Integrated Tools) and ASSESS (Analytic System and Software for Evaluating Safeguards and Security). ACE is an existing DOD PC-based tool that supports cost analysis over the full life cycle of a system; that is, the cost to

M. J. Hicks; D. Yates; W. H. Jago

1997-01-01

413

Geodesic spaces and harmonic maps.  

National Technical Information Service (NTIS)

This brief summary contains discussions of smooth geometry, metric geometry, first applications of tensor calculus, geometry in geodesic spaces, and harmonic maps. 6 refs. (Atomindex citation 27:026727)

J. Eells

1995-01-01

414

The technical analysis of the stock exchange and physics: Japanese candlesticks for solar activity  

NASA Astrophysics Data System (ADS)

In this article, we use the Japanese candlesticks, a method popular in the technical analysis of the Stock/Forex markets and apply it to a variable in physics-the solar activity. This method is invented and used exclusively for economic analysis and its application to a physical problem produced unexpected results. We found that the Japanese candlesticks are convenient tool in the analysis of the variables in the physics of the Sun. Based on our observations, we differentiated a new cycle in the solar activity.

Dineva, C.; Atanasov, V.

2013-09-01

415

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

416

Azimuthal anisotropy: The higher harmonics  

SciTech Connect

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

Poskanzer, Arthur M.; STAR Collaboration

2004-03-12

417

Limits: Geometric and Harmonic Series  

NSDL National Science Digital Library

A geometric series is a sum of numbers such that the ratio between consecutive terms is constant. For instance, 1/2 + 1/4 + 1/8 + … is a geometric series. The harmonic series is the sum of all numbers 1/n for nn = 1, 2, 3, …. In this activity, you can see a representation of three geometric series and the harmonic series.

Mathematics, Illuminations N.

2010-05-26

418

Simulated Study of Three-Phase Single-Switch PFC Converter with Harmonic Injected PWM by MATLAB  

Microsoft Academic Search

This paper describes the operation and simulation of a three-phase single-switch PFC converter with a sixth-order harmonic-injection PWM. The PFC converter operates in a discontinuous current mode (DCM). In proposed method, the sixth-order harmonic is injected in PWM so that the harmonic content of the input current meet IEC555-2(A) requirement. The theoretical analysis of the harmonic-injection is discussed. Furthermore, the

Zhanlong Li; Yupeng Tang

2006-01-01

419

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

420

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

421

Mapping university students' epistemic framing of computational physics using network analysis  

NASA Astrophysics Data System (ADS)

Solving physics problem in university physics education using a computational approach requires knowledge and skills in several domains, for example, physics, mathematics, programming, and modeling. These competences are in turn related to students’ beliefs about the domains as well as about learning. These knowledge and beliefs components are referred to here as epistemic elements, which together represent the students’ epistemic framing of the situation. The purpose of this study was to investigate university physics students’ epistemic framing when solving and visualizing a physics problem using a particle-spring model system. Students’ epistemic framings are analyzed before and after the task using a network analysis approach on interview transcripts, producing visual representations as epistemic networks. The results show that students change their epistemic framing from a modeling task, with expectancies about learning programming, to a physics task, in which they are challenged to use physics principles and conservation laws in order to troubleshoot and understand their simulations. This implies that the task, even though it is not introducing any new physics, helps the students to develop a more coherent view of the importance of using physics principles in problem solving. The network analysis method used in this study is shown to give intelligible representations of the students’ epistemic framing and is proposed as a useful method of analysis of textual data.

Bodin, Madelen

2012-06-01

422

Correlations in Quantum Physics  

NASA Astrophysics Data System (ADS)

We provide a historical perspective of how the notion of correlations has evolved within quantum physics. We begin by reviewing Shannon's information theory and its first application in quantum physics, due to Everett, in explaining the information conveyed during a quantum measurement. This naturally leads us to Lindblad's information theoretic analysis of quantum measurements and his emphasis of the difference between the classical and quantum mutual information. After briefly summarizing the quantification of entanglement using these ideas, we arrive at the concept of quantum discord, which naturally captures the boundary between entanglement and classical correlations. Finally we discuss possible links between discord, which the generation of correlations in thermodynamic transformations of coupled harmonic oscillators.

Dorner, Ross; Vedral, Vlatko

2013-01-01

423

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

424

PREDICTING PHYSICAL PROPERTIES OF RESERVOIR ROCKS FROM THE MICROSTRUCTURAL ANALYSIS OF PETROGRAPHIC THIN SECTIONS  

Microsoft Academic Search

Important physical properties of petroleum reservoirs are, usually, obtained by applying standard experimental tests on rock samples collected along selected depths of the petroleum well. This is, presently, a laborious and high cost procedure. Present paper describes Imago, which is a new petrographic analysis software, developed for predicting the physical properties of reservoir rocks, starting from petrographic thin sections routinely

M. C. Damiani; A. D. Bueno; L. O. E. Santos; J. A. B. da Cunha; P. C. Philippi

425

PREFACE: 7th International Conference on Applications of Physics in Financial Analysis  

Microsoft Academic Search

This volume contains contributed papers from the 7th international conference on 'Applications of Physics in Financial Analysis (APFA)' held at Tokyo on 1-5 March 2009. The conference was organized jointly by Tokyo Institute of Technology and Hitotsubashi University with support from the Research Institute of Economy, Trade, and Industry (RIETI), Physical Society of Japan, Japanese Economic Association, Information Processing Society

M. Takayasu; T. Watanabe; Y. Ikeda; H. Takayasu

2010-01-01

426

Cost and performance analysis of conceptual designs of physical protection systems  

Microsoft Academic Search

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

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

1998-01-01

427

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

428

Orbit determination and analysis for Cosmos 58 at 15th-order resonance, to evaluate geopotential harmonics of order 15 and 30  

NASA Astrophysics Data System (ADS)

The orbital parameters of Cosmos 58 have been determined at 65 epochs from some 4500 observations, between March 1982 and September 1983, using the RAE orbit refinement program, PROP. During this time, the satellite passed slowly through 15th-order resonance, and the orbital inclination and eccentricity have been analyzed. Six lumped 15th-order geopotential harmonic coefficients have been evaluated, with an accuracy equivalent to between 0.8 and 2.0 cm in geoid height. Six 30th-order coefficients have also been determined, with accuracies between 2 and 7 cm in geoid height. The coefficients have been compared with those from the GEM 10B and 10C models. There is good agreement for nine of the twelve coefficients.

Walker, Doreen M. C.

1986-12-01

429

Physical data generation methodology for return-to-power steam line break analysis.  

National Technical Information Service (NTIS)

Current methodology to generate physics data for steamline break accident analysis of CE-type nuclear plant, such as Yonggwang Unit 3, is valid only if the core reactivity does not reach the criticality after shutdown. Therefore, the methodology requires ...

S. K. Zee C. C. Lee C. K. Lee

1996-01-01

430

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

431

Harmonization of the intracellular cytokine staining assay.  

PubMed

Active immunotherapy for cancer is an accepted treatment modality aiming to reinforce the T-cell response to cancer. T-cell reactivity is measured by various assays and used to guide the clinical development of immunotherapeutics. However, data obtained across different institutions may vary substantially making comparative conclusions difficult. The Cancer Immunotherapy Immunoguiding Program organizes proficiency panels to identify key parameters influencing the outcome of commonly used T-cell assays followed by harmonization. Our successes with IFN?-ELISPOT and peptide HLA multimer analysis have led to the current study on intracellular cytokine staining (ICS). We report the results of three successive panels evaluating this assay. At the beginning, 3 out of 9 participants (33 %) were able to detect >6 out of 8 known virus-specific T-cell responses in peripheral blood of healthy individuals. This increased to 50 % of the laboratories in the second phase. The reported percentages of cytokine-producing T cells by the different laboratories were highly variable with coefficients of variation well over 60 %. Variability could partially be explained by protocol-related differences in background cytokine production leading to sub-optimal signal-to-noise ratios. The large number of protocol variables prohibited identification of prime guidelines to harmonize the assays. In addition, the gating strategy used to identify reactive T cells had a major impact on assay outcome. Subsequent harmonization of the gating strategy considerably reduced the variability within the group of participants. In conclusion, we propose that first basic guidelines should be applied for gating in ICS experiments before harmonizing assay protocol variables. PMID:22714399

Welters, Marij J P; Gouttefangeas, Cécile; Ramwadhdoebe, Tamara H; Letsch, Anne; Ottensmeier, Christian H; Britten, Cedrik M; van der Burg, Sjoerd H

2012-05-22

432

Review of physics methodology of ATR safety analysis  

SciTech Connect

At the request of EG G Idaho, the Pacific Northwest Laboratory (PNL) performed a brief review of the physics methods employed in the safety analyses for the Advanced Test Reactor. PNL determined that the general approach used by EG G was sound. Comparisons were made between the EG G results and a simplified PBL model. These demonstrated good agreement. However, the lack of spacial treatment of the moderator density reactivity coefficient and exclusion of the test loops from the reactivity model were identified as potential problems. In addition to these two concerns, a series of more minor observations were offered to assist EG G in their analyses. 2 refs., 2 figs.

Little, W.W.; Heaberlin, S.W.

1991-09-01

433

Genetic analysis of physical activity in twins1,2  

Microsoft Academic Search

Background:The reduced contribution of physical activity (PA) to daily energy expenditure contributes to the increased prevalence of obesity. A genetic control of activity-induced energy expenditure (AEE) may contribute to a genetic susceptibility to obesity. Objective: Our aim was to investigate the relative contribution of geneticandenvironmentalfactorstothevariationandcovariationin AEE and PA. Design: Twelve monozygotic and 8 same-sex dizygotic (including 2same-sexsiblingpairs;agedifferences:2and2.5y)twinpairsaged between18and39yparticipated.AEEwasmeasuredinarespiration chamberfor24handwithdoublylabeledwaterindailylifefor2wk. PA

Annemiek MCP Joosen; Marij Gielen; Robert Vlietinck; Klaas R Westerterp

434

Physics Courses X-Rayed - A Comparative Analysis of High School Physics Courses in Terms of Basic Assumptions  

ERIC Educational Resources Information Center

|Reports an attempt to infer from official statements and from course materials some of the assumptions and theoretical positions which underlie four high school physics courses: Nuffield Physics, ECCP's "The Man Made World," Harvard Project Physics, and PSSC Physics. (PEB)|

Hobbs, E. D.

1974-01-01

435

Unbiased Analysis of Super/Ferro Bilayer Physics  

NASA Astrophysics Data System (ADS)

S/F bilayer physics has been studied for some time now. With a large number of unknown and seemingly-known parameters, some values are traditionally and understandably assumed to be fixed quantities. In particular, the exchange energy, Eex/kB, is believed to be comparable to the Curie temperature. We analyze the data assuming only that the Fermi velocity vF in F and the density of states, 2NS(0), in S are known. Fitting Tc vs. dF with the dirty-limit theory, we determine the interface resistance, Rb, the ratio Eex/?FlF, and the ferromagnetic coherence length ?F. For physically plausible values of ?FlF, the dephasing rate of cooper pairs in F is 10 times smaller than expected from the known Curie temperature of F. We propose that dephasing is mitigated by spin-orbit scattering. We also find that the transmission probability for electrons striking the F/S interface is much less than unity.

Lemberger, Thomas; Hinton, Michael; Yong, Jie; Hauser, Adam; Yang, Fengyuan; Meyer, Julia

2013-03-01

436

Applications of mathematical analysis of nonlinear physical systems  

SciTech Connect

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). In this project we have sought to acquire the basic theoretical and computational capabilities needed to advance our understanding of the physical sciences. We concentrated on physical systems governed by transport equations. Transport equations were chosen because they govern many critical technologies. They govern the flow of carriers in semiconductors, the dynamics of nuclear reactors, the transport of radiation in fusion experiments, and even the probability densities of stochastic equations. Besides being important in its own right, this research serves as an important paradigm for using computers to solve other key scientific problems. Transport problems are often characterized by mean free paths that are short compared to the other critical length scales of the system. We exploit this feature to both simplify the solution of transport equations and to gain insights into the results. To explore industrial applications of the science developed in this project, a workshop was sponsored highlighting eight to ten problems from industry. Promising research avenues were uncovered that might lead to potential collaborations with industry.

Frauenfelder, H.; Hagan, P.; Sobehart, J.; Ueda, Tetsuji

1996-07-01

437

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

438

Calculation of four-particle harmonic-oscillator transformation brackets  

NASA Astrophysics Data System (ADS)

A procedure for precise calculation of the three- and four-particle harmonic-oscillator (HO) transformation brackets is presented. The analytical expressions of the four-particle HO transformation brackets are given. The computer code for the calculations of HO transformation brackets proves to be quick, efficient and produces results with small numerical uncertainties. Catalogue identifier: AEFQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1247 No. of bytes in distributed program, including test data, etc.: 6659 Distribution format: tar.gz Programming language: FORTRAN 90 Computer: Any computer with FORTRAN 90 compiler Operating system: Windows, Linux, FreeBSD, True64 Unix RAM: 8 MB Classification: 17.17 Nature of problem: Calculation of the three-particle and four-particle harmonic-oscillator transformation brackets. Solution method: The method is based on compact expressions of the three-particle harmonics oscillator brackets, presented in [1] and expressions of the four-particle harmonics oscillator brackets, presented in this paper. Restrictions: The three- and four-particle harmonic-oscillator transformation brackets up to the e=28. Unusual features: Possibility of calculating the four-particle harmonic-oscillator transformation brackets. Running time: Less than one second for the single harmonic-oscillator transformation bracket. References:G.P. Kamuntavi?ius, R.K. Kalinauskas, B.R. Barret, S. Mickevi?ius, D. Germanas, Nuclear Physics A 695 (2001) 191.

Germanas, D.; Kalinauskas, R. K.; Mickevi?ius, S.

2010-02-01

439

Quantum path contribution to high-order harmonic spectra  

SciTech Connect

Ultrashort pulses of uv and soft x-ray radiation with durations ranging from femtoseconds to attoseconds can be produced as high-order harmonics of the fundamental frequency of a laser beam focused into gas. Applications to fields such as spectroscopy and attosecond metrology require the control and characterization of spectral and spatial properties of the emitted radiation. These are determined by both single atom and macroscopic response of the interaction medium to the laser field. Here we present evidence that microscopic effects have a larger influence than previously thought, and can induce a splitting and a frequency shift of the harmonic lines. These results not only offer a direct diagnostic for high-order harmonic generation, but also enable us to better tune the parameters of the produced radiation, while giving a deeper insight into the fundamental physics underlying this nonlinear optical process.

Brunetti, E.; Issac, R.; Jaroszynski, D. A. [Department of Physics, University of Strathclyde, 107 Rottenrow, G4 0NG Glasgow (United Kingdom)

2008-02-15

440

A combined planning and self-efficacy intervention to promote physical activity: a multiple mediation analysis.  

PubMed

Many individuals are motivated to improve their physical activity levels, but often fail to act upon their intention. Interventions fostering volitional strategies, such as action planning, coping planning, and self-efficacy beliefs, can help to translate intentions into behavior. This study examines the effectiveness and the mechanisms of a combined planning and self-efficacy intervention to promote physical activity among motivated individuals. Participants (N = 883) were randomly assigned to the intervention or to a waiting-list control condition. Multivariate analysis of variance revealed that the intervention resulted in significantly more physical activity, higher levels of action planning, coping planning, and volitional self-efficacy beliefs (p < 0.01). In addition, multiple mediation analysis showed that action planning, coping planning, and volitional self-efficacy mediate between the intervention and physical activity. The study shows that the intervention successfully fostered physical activity and unfolds the underlying self-regulatory mechanisms of the intervention's effectiveness. PMID:22007933

Koring, Milena; Richert, Jana; Parschau, Linda; Ernsting, Anna; Lippke, Sonia; Schwarzer, Ralf

2011-10-18

441

An analysis of science content and representations in introductory college physics textbooks and multimodal learning resources  

NASA Astrophysics Data System (ADS)

This study features a comparative descriptive analysis of the physics content and representations surrounding the first law of thermodynamics as presented in four widely used introductory college physics textbooks representing each of four physics textbook categories (calculus-based, algebra/trigonometry-based, conceptual, and technical/applied). Introducing and employing a newly developed theoretical framework, multimodal generative learning theory (MGLT), an analysis of the multimodal characteristics of textbook and multimedia representations of physics principles was conducted. The modal affordances of textbook representations were identified, characterized, and compared across the four physics textbook categories in the context of their support of problem-solving. Keywords: college science, science textbooks, multimodal learning theory, thermodynamics, representations

Donnelly, Suzanne M.

442

The California Current system: The seasonal variability of its physical characteristics  

Microsoft Academic Search

The seasonal variation of the physical characteristics and of large-scale current patterns of the California Current system is examined using harmonic analysis applied to the 23 years of California cooperative Oceanic Fisheries Investigations data collected between 1950 and 1978. The amplitude and phasing of seasonal variation in dynamic height and the overall standard deviation of dynamic height define three domains:

Ronald J. Lynn; James J. Simpson

1987-01-01

443

Geometry Description Markup Language for Physics Simulation And Analysis Applications.  

SciTech Connect

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

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

2007-01-23

444

Analysis of the numerics of physics-dynamics coupling  

NASA Astrophysics Data System (ADS)

A methodology for analysing the numerical properties of schemes for coupling physics parametrizations to a dynamical core is presented. As an example of its application, the methodology is used to study four coupling schemes ('explicit', 'implicit', 'split-implicit' and 'symmetrized split-implicit') in the context of a semi-implicit semi-Lagrangian dynamical core. Each coupling scheme is assessed in terms of its numerical stability and of the accuracy of both its transient and steady-state responses. Additionally, the occurrence of spurious, computational resonance is analysed and discussed. It is found that in this respect all four schemes behave similarly.In particular, in the absence of any damping mechanism to control resonance, the time-step restriction needed to avoid spurious resonance is twice as restrictive for time-dependent forcing as for stationary forcing.

Staniforth, Andrew; Wood, Nigel; Côté, Jean

2002-10-01

445

Shock Physics Analysis to Support Optical Signature Prediction in Hypervelocity Impacts  

NASA Astrophysics Data System (ADS)

In a recent series of light-gas-gun experiments performed at Sandia National Laboratories, aluminum projectiles impacted titanium alloy plates at 6 km/s, with a variety of witness plates downstream. The radiative characteristics of the target debris cloud were measured using a combination of time-resolved visible emission spectroscopy and high-speed wavelength-filtered camera imagery. This paper will describe the analyses performed in support of the test series using the CTH shock-physics package from Sandia, discuss the methodology developed to port CTH results into radiation-physics codes, and provide comparisons between CTH results and experimental observations of debris-cloud shape. The combination of high-fidelity shock-physics analysis and high-fidelity spectral analysis of the shock-physics results represents a first-principles approach toward optical signature prediction in hypervelocity impacts. Details on the radiation analysis techniques and results will be presented in a companion paper.

Ward, Aaron J.; Nance, Robert P.; Cogar, John R.; Macfarlane, Joseph J.; Reinhart, William D.; Thornhill, Thomas F.; Grun, Jacob; Lunsford, Robert

2011-06-01

446

Physical and Chemical Analytical Analysis: A key component of Bioforensics  

Microsoft Academic Search

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

S. P. Velsko

2005-01-01

447

Global and Local Sensitivity Analysis Methods for a Physical System  

ERIC Educational Resources Information Center

|Sensitivity analysis is the study of how the different input variations of a mathematical model influence the variability of its output. In this paper, we review the principle of global and local sensitivity analyses of a complex black-box system. A simulated case of application is given at the end of this paper to compare both approaches.…

Morio, Jerome

2011-01-01

448

Spatial Variability Analysis of Soil Physical Properties of Alluvial Soils  

Microsoft Academic Search

ited on sandy or on loamy sediments. Therefore, it is important to study not only the extent of surface spatial Analysis and interpretation of spatial variability of soils is a key- variability, but also the distribution of subsurface and stone in site-specific farming. Soil survey maps may have up to 0.41- ha inclusions of dissimilar soils within a mapping unit.

Javed Iqbal; John A. Thomasson; Johnie N. Jenkins; Phillip R. Owens; Frank D. Whisler

2005-01-01

449

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

450

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

451

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

452

Interaction and learning: An analysis of two freshman physics courses  

NASA Astrophysics Data System (ADS)

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

Clark, Dexter

453

Mechanical, physical, and physiological analysis of symmetrical and asymmetrical combat.  

PubMed

In current theaters of operation, soldiers had to face a different situation as symmetrical (defined battlefield) and asymmetrical combat (non-defined battlefield), especially in urban areas. The mechanical and organic responses of soldiers in these combats are poorly studied in specific literature. This research aimed to analyze physical, mechanical, and physiological parameters during symmetrical and asymmetrical combat simulations. We analyzed 20 soldiers from the Spanish Army and Spanish Forces and Security Corps (34.5 ± 4.2 years; 176.4 ± 8.4 cm; 74.6 ± 8.7 kg; 63.3 ± 8.0 kg muscular mass; 7.6 ± 3.2 kg fat mass) during a symmetric combat (traditional combat simulation) and during an asymmetrical combat (urban combat simulation). Heart rate (HR), speed, sprints, distances, impact, and body load parameters were measured by a GPS system and a HR belt. Results showed many differences between symmetrical and asymmetrical combat. Asymmetrical combat presented higher maximum velocity movement, number of sprints, sprint distance, and average HR. By contrary, symmetric combat presented higher number of impact and body load. This information could be used to improve specific training programs for each type of combat. PMID:23254545

Clemente-Suárez, Vicente J; Robles-Pérez, José J

2013-09-01

454

Analysis of physical and chemical parameters of bottled drinking water.  

PubMed

Seventeen different brands of bottled drinking water, collected from different retail shops in Amritsar, were analyzed for different physical and chemical parameters to ascertain their compliability with the prescribed/recommended limits of the World Heath Organization (WHO) and the United States Environmental Protection Agency (USEPA). It was found that the majority of the brands tested were over-treated. Lower values of hardness, total dissolved solids (TDS) and conductance than the prescribed limits of WHO showed that water was deficient in essential minerals. Minerals like magnesium, potassium, calcium and fluoride were present in some cases in such a low concentration that water seemed to be as good as distilled water. Samples showing fluoride lesser than 0.5 mg/l warranted additional sources of fluoride for the people consuming only bottled water for drinking purposes. Zero values for chlorine demand as shown by all the bottled water samples showed that water samples were safe from micro-organisms. In case of heavy metals, only lead had been found to be greater than the limit of 0.015 mg/l as prescribed by WHO and USEPA, in seven out of 17 samples. Lead even at such a low concentration can pose a great health hazard. PMID:16602194

Mahajan, Rakesh Kumar; Walia, T P S; Lark, B S; Sumanjit

2006-04-01

455

Efficient dynamic synchronous machine simulation with harmonics  

SciTech Connect

Within this paper, an efficient procedure for the dynamic simulation of faulted synchronous machines operating in the presence of harmonics is presented. The algorithm employs steady-state frequency domain techniques for simulation of the transmission system sequence networks and time domain methods for the synchronous machines represented in the odq frame of reference. The procedure affords greater accuracy than conventional fault analysis techniques based strictly on steady-state methods, yet requires far less computational time than full system dynamic simulations such as those using the EMTP.

Haskew, T.A.; Stern, H.P.; Chen, Z. [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Electrical Engineering

1996-06-01

456

Multi-photon excitation fluorescence and third-harmonic generation microscopy measurements combined with confocal Raman microscopy for the analysis of layered samples of varnished oil films  

NASA Astrophysics Data System (ADS)

The non-destructive determination of layer structures in works of art remains a significant challenge. Non-linear microscopy and confocal Raman microscopy (CRM) were employed for characterisation of varnish-media layers in model samples, providing important information regarding the thickness of materials and the identification of different media in depth. Commonly found triterpenoid varnishes mastic and dammar were applied over a single layer of films of linseed oil. Non-linear microscopy of samples was carried out using a 1028-nm femtosecond laser source; both third-harmonic generation signals (THG) and three-photon fluorescence signals (3PEF) of samples were collected in an effort to measure the thickness of mono- and bi-layers; in parallel scans of larger areas were undertaken to assess heterogeneities in samples with spatial resolution of ˜2 ?m. Complementary spectroscopic information from CRM collected with both a 514.5-nm argon-ion and a 785-nm diode lasers coupled with a 100X objective and a motorised stage was carried out. Comparison of C-H stretching regions of Raman spectra allowed the differentiation between different molecular materials and the fingerprint region was employed for the depth profiling of the samples.

Nevin, A.; Comelli, D.; Osticioli, I.; Filippidis, G.; Melessanaki, K.; Valentini, G.; Cubeddu, R.; Fotakis, C.

2010-09-01

457

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.

Shephard, Roy J.

1986-01-01

458

Computer analysis and optimization of physical and material parameters of the blue laser diode  

Microsoft Academic Search

The computer analysis and optimisation of various physical and material parameters of the blue laser diode have been presented. Numerical analysis of basic electrical equations, which include Poisson's equation and current continuity equations for the electrons and holes, has been carried out using finite difference method. The wave equation is solved using effective index method to obtain transverse electric field.

Dnyaneshwar S. Patil; D. K. Gautam

2002-01-01

459

Physical and Chemical Analysis of Dielectric Properties and Differential Scanning Calorimetry Techniques on Buriti Oil  

Microsoft Academic Search

Dielectric constant (DC) analysis has been carried out on buriti oil (Mauritia flexuosa), in a scan temperature range of ?100–40°C. Fatty acid characterization was performed by gas crystallography and differential scanning calorimetry (DSC). Interesting physical characteristics were noted in a DC analysis on buriti oil. It revealed five different temperature anomalies, which were studied for the chemical properties of the

A. Garcia-Quiroz; S. G. C. Moreira; A. V. de Morais; A. S. Silva; G. N. da Rocha; P. Alcantara

2003-01-01

460

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

461

An epistemic framing analysis of upper level physics students' use of mathematics  

NASA Astrophysics Data System (ADS)

Mathematics is central to a professional physicist's work and, by extension, to a physics student's studies. It provides a language for abstraction, definition, computation, and connection to physical reality. This power of mathematics in physics is also the source of many of the difficulties it presents students. Simply put, many different activities could all be described as "using math in physics". Expertise entails a complicated coordination of these various activities. This work examines the many different kinds of thinking that are all facets of the use of mathematics in physics. It uses an epistemological lens, one that looks at the type of explanation a student presently sees as appropriate, to analyze the mathematical thinking of upper level physics undergraduates. Sometimes a student will turn to a detailed calculation to produce or justify an answer. Other times a physical argument is explicitly connected to the mathematics at hand. Still other times quoting a definition is seen as sufficient, and so on. Local coherencies evolve in students' thought around these various types of mathematical justifications. We use the cognitive process of framing to model students' navigation of these various facets of math use in physics. We first demonstrate several common framings observed in our students' mathematical thought and give several examples of each. Armed with this analysis tool, we then give several examples of how this framing analysis can be used to address a research question. We consider what effects, if any, a powerful symbolic calculator has on students' thinking. We also consider how to characterize growing expertise among physics students. Framing offers a lens for analysis that is a natural fit for these sample research questions. To active physics education researchers, the framing analysis presented in this dissertation can provide a useful tool for addressing other research questions. To physics teachers, we present this analysis so that it may make them more explicitly aware of the various types of reasoning, and the dynamics among them, that students employ in our physics classes. This awareness will help us better hear students' arguments and respond appropriately.

Bing, Thomas Joseph

462

Analysis of WiMAX Physical Layer using Spatial Diversity  

NASA Astrophysics Data System (ADS)

Broadband Wireless Access (BWA) has emerged as a promising solution for providing last mile internet access technology to provide high speed internet access to the users in the residential as well as in the small and medium sized enterprise sectors. IEEE 802.16e is one of the most promising and attractive candidate among the emerging technologies for broadband wireless access. The emergence of WiMAX protocol has attracted various interests from almost all the fields of wireless communications. MIMO systems which are created according to the IEEE 802.16-2005 standard (WiMAX) under different fading channels can be implemented to get the benefits of both the MIMO and WiMAX technologies. In this paper analysis of higher level of modulations (i.e. M-PSK and M-QAM for different values of M) with different code rates and on WiMAX-MIMO system is presented for Rayleigh channel by focusing on spatial multiplexing MIMO technique. Signal-to Noise Ratio (SNR) vs Bit Error Rate (BER) analysis has been done.

Sanghoi, Pavani; Kansal, Lavish

2012-04-01

463

High order harmonic balance formulation of free and encapsulated microbubbles  

NASA Astrophysics Data System (ADS)

The radial responses of free and encapsulated microbubbles excited by an ultrasonic plane wave with a large wavelength in comparison with the bubble size are governed by NonLinear Ordinary Differential Equations (NL-ODEs). The nonlinear frequency response gives the harmonic content of the time response and constitutes the expected outcome of a high order harmonic analysis. In this paper, high order harmonic balance analysis of modified “RPNNP” (bubble), Hoff and Marmottant (contrast agents) models is performed with an open-source software program. For this purpose, the original NL-ODEs are recast into nonlinear systems in which the nonlinearities are at most quadratic. In the spectral domain, this recast provides close form and aliasing-free solutions of arbitrarily large numbers of harmonics. Relevant quantities such as primary and secondary resonances and the nonlinear amplitude threshold of the excitation wave are evaluated. The frequency curves drawn up characterize the bending and quantify the jump frequencies and amplitudes of each harmonic component. The results obtained with this