Numerical investigation of optimal yaw misalignment and collective pitch angle for load imbalance reduction of rigid and flexible HAWT blades under sheared inflow

International Nuclear Information System (INIS)

Jeong, Min-Soo; Cha, Myung-Chan; Kim, Sang-Woo; Lee, In

2015-01-01

Wind shear can strongly influence the cyclic loading on horizontal axis wind turbine blades. These load fluctuation causes a variation of power output and introduces fatigue load. Thus, individual pitch controllers have been developed that are focused on the load alleviations, however, comes at a price of actuator requirements for control. Moreover, these controllers are unable to apply to already existing wind turbines with active yaw and collective pitch control system. Therefore, the investigations for minimizing load imbalance through the adjustments of yaw misalignment and collective pitch angle are implemented for the rigid and flexible blades under the sheared inflow. By applying the optimization process based on a sequential quadratic programming approach, the optimal yaw and pitch angle can be estimated. Then, the numerical simulations for predicting the performance are performed. The results showed that the fluctuation range of the root flapwise bending moment for the rigid blades can be reduced by 84.5%, whereas the vibratory bending moment for the flexible blades can be reduced by up to approximately 82.4% in the best case. Therefore, the magnitudes of load imbalance can be minimized by the adjustment of the optimal yaw misalignment and collective pitch angle without any power loss. - Highlights: • We propose a novel method for the reduction of load imbalance under sheared inflow. • We estimate optimal yaw misalignment and collective pitch angle through optimization. • Numerical results of performance are predicted for rigid and flexible blades. • By applying optimal angles, load variations are reduced without any power loss

Using a Neural Network Approach to Find Unusual Butterfly Pitch Angle Distribution Shapes

Science.gov (United States)

Medeiros, C.; Sibeck, D. G.; Souza, V. M. C. E. S.; Vieira, L.; Alves, L. R.; Da Silva, L. A.; Kanekal, S. G.; Baker, D. N.

2017-12-01

A special kind of neural network referred to as a Self-Organizing Map (SOM) was previously adopted to identify, in pitch angle-resolved relativistic electron flux data provided by the REPT instrument onboard the Van Allen Probes, three major types of electron pitch angle distributions (PADs), namely 90o-peaked, butterfly and flattop (Souza et al., 2016), following the classification scheme employed by Gannon et al. (2007). Previous studies show that butterfly distribution can be found in more than one shape. They usually exhibit an intense decrease near 90° pitch angles compared to the peaks usually around 30° and 150°. Sometimes unusual butterfly PAD shapes with peaks near 45° and 135° pitch angles can be observed. These could be correlated with different physical processes that govern the production and loss of energetic particles in the Van Allen radiation belt. A neural network approach allows the distinction of different kinds of butterfly PADs which were not analyzed in detail by Souza et al. (2016). This study uses SOM methodology to find these unusual butterfly PAD shape during the interval between January 1, 2014 and October 1, 2015, during which Van Allen Probes orbit covered all MLT. The spatial and temporal occurrence of these events were investigated as well as their solar wind and magnetospheric drivers.

The influence of the formation pitching angle on the area for employing the KM-103 complex

Energy Technology Data Exchange (ETDEWEB)

Shulga, A I; Teryanik, V I

1982-01-01

Mining sections in which the KM-103 powered complexes are used should be selected and planned on the basis of the actual pitching angle of the formation, and the anticipated vertical and lateral rock displacement in the workings. With the shapes and dimensions characteristic of galley cross-sections which are reinforced by arched 3 and 5-arm supports, and with the anticipated values of rock displacement, a maximum pitching angle exists, above which it is difficult to facilitate the drives of stope face conveyors. For arch-shaped galleys, which are reinforced by an arched 5-arm support, the maximum pitching angle of the formation is greater than in galleys which are reinforced by arched three-arm supports, with equal cross-sections even with large rock displacements. An increase in the cross-section of upwards of 13 square meters does not result in an increase in the maximum pitching angle of the formation due to the extension of the support roof timber. In the trapezoidal workings which are supported by the KPS-3 supports and are worked without employing roof blasting, the maximum pitching angle of the formation is 12 degrees. The thickness of the formation worked must be less than 1.1 meter.

MEASUREMENT OF GALACTIC LOGARITHMIC SPIRAL ARM PITCH ANGLE USING TWO-DIMENSIONAL FAST FOURIER TRANSFORM DECOMPOSITION

International Nuclear Information System (INIS)

Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

2012-01-01

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-dimensional Fast Fourier Transform Decomposition

Science.gov (United States)

Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

2012-04-01

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

MEASUREMENT OF GALACTIC LOGARITHMIC SPIRAL ARM PITCH ANGLE USING TWO-DIMENSIONAL FAST FOURIER TRANSFORM DECOMPOSITION

Energy Technology Data Exchange (ETDEWEB)

Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S. [Arkansas Center for Space and Planetary Sciences, 202 Field House, University of Arkansas, Fayetteville, AR 72701 (United States); Puerari, Ivanio [Instituto Nacional de Astrofisica, Optica y Electronica, Calle Luis Enrique Erro 1, 72840 Santa Maria Tonantzintla, Puebla (Mexico)

2012-04-01

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

Design of a wind turbine pitch angle controller for power system stabilisation

Energy Technology Data Exchange (ETDEWEB)

Jauch, Clemens; Soerensen, Poul [Risoe National Laboratory, Wind Energy Department, P.O. Box 49, DK-4000 Roskilde (Denmark); Islam, Syed M. [Department of Electrical and Computer Engineering, Curtin University of Technology, GPO Box U1987, Perth, WA 6845 (Australia); Bak Jensen, Birgitte [Institute of Energy Technology, Aalborg University, Pontoppidanstraede 101, DK-9220 Aalborg East (Denmark)

2007-11-15

The design of a PID pitch angle controller for a fixed speed active-stall wind turbine, using the root locus method is described in this paper. The purpose of this controller is to enable an active-stall wind turbine to perform power system stabilisation. For the purpose of controller design, the transfer function of the wind turbine is derived from the wind turbine's step response. The performance of this controller is tested by simulation, where the wind turbine model with its pitch angle controller is connected to a power system model. The power system model employed here is a realistic model of the North European power system. A short circuit fault on a busbar close to the wind turbine generator is simulated, and the dynamic responses of the system with and without the power system stabilisation of the wind turbines are presented. Simulations show that in most operating points the pitch controller can effectively contribute to power system stabilisation. (author)

Design of a wind turbine pitch angle controller for power system stabilisation

DEFF Research Database (Denmark)

Jauch, Clemens; Islam, S.M.; Sørensen, Poul Ejnar

2007-01-01

The design of a PID pitch angle controller for a fixed speed active-stall wind turbine, using the root locus method is described in this paper. The purpose of this controller is to enable an active-stall wind turbine to perform power system stabilisation. For the purpose of controller design......, the transfer function of the wind turbine is derived from the wind turbine's step response. The performance of this controller is tested by simulation, where the wind turbine model with its pitch angle controller is connected to a power system model. The power system model employed here is a realistic model...... of the North European power system. A short circuit fault on a busbar close to the wind turbine generator is simulated, and the dynamic responses of the system with and without the power system stabilisation of the wind turbines are presented. Simulations show that in most operating points the pitch controller...

Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

Science.gov (United States)

Hao, Y.; Zong, Q.; Zhou, X.; Rankin, R.; Chen, X.; Liu, Y.; Fu, S.; Spence, H. E.; Blake, J. B.; Reeves, G. D.

2017-12-01

We present an analysis of "boomerang-shaped" pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on June 7th, 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90º pitch angle electrons, the phase change of the flux modulations across energy exceeds 180º, and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wave field reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift-resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.

Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

International Nuclear Information System (INIS)

Hao, Y. X.; Zong, Q.-G.; Zhou, X.-Z.; Rankin, R.; Chen, X. R.

2017-01-01

Here, we present an analysis of “boomerang-shaped” pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on 7 June 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90° pitch angle electrons, the phase change of the flux modulations across energy exceeds 180° and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wavefield reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.

Pitch-angle diffusion coefficients from resonant interactions with electrostatic electron cyclotron harmonic waves in planetary magnetospheres

Directory of Open Access Journals (Sweden)

A. K. Tripathi

2011-02-01

Full Text Available Pitch-angle diffusion coefficients have been calculated for resonant interaction with electrostatic electron cyclotron harmonic (ECH waves in the magnetospheres of Earth, Jupiter, Saturn, Uranus and Neptune. Calculations have been performed at two radial distances of each planet. It is found that observed wave electric field amplitudes in the magnetospheres of Earth and Jupiter are sufficient to put electrons on strong diffusion in the energy range of less than 100 eV. However, for Saturn, Uranus and Neptune, the observed ECH wave amplitude are insufficient to put electrons on strong diffusion at any radial distance.

Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-Dimensional Fast Fourier Transform Decomposition

OpenAIRE

Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

2012-01-01

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quanti...

Evolution of electron pitch angle distributions across Saturn's middle magnetospheric region from MIMI/LEMMS

Science.gov (United States)

Clark, G.; Paranicas, C.; Santos-Costa, D.; Livi, S.; Krupp, N.; Mitchell, D. G.; Roussos, E.; Tseng, W.-L.

2014-12-01

We provide a global view of ~20 to 800 keV electron pitch angle distributions (PADs) close to Saturn's current sheet using observations from the Cassini MIMI/LEMMS instrument. Previous work indicated that the nature of pitch angle distributions in Saturn's inner to middle magnetosphere changes near the radial distance of 10RS. This work confirms the existence of a PAD transition region. Here we go further and develop a new technique to statistically quantify the spatial profile of butterfly PADs as well as present new spatial trends on the isotropic PAD. Additionally, we perform a case study analysis and show the PADs exhibit strong energy dependent features throughout this transition region. We also present a diffusion theory model based on adiabatic transport, Coulomb interactions with Saturn's neutral gas torus, and an energy dependent radial diffusion coefficient. A data-model comparison reveals that adiabatic transport is the dominant transport mechanism between ~8 to 12RS, however interactions with Saturn's neutral gas torus become dominant inside ~7RS and govern the flux level of ~20 to 800 keV electrons. We have also found that field-aligned fluxes were not well reproduced by our modeling approach. We suggest that wave-particle interactions and/or a polar source of the energetic particles needs further investigation.

Conical pitch angle distributions of very-low energy ion fluxes observed by ISEE 1

International Nuclear Information System (INIS)

Horowitz, J.L.; Baugher, C.R.; Chappell, C.R.; Shelley, E.G.; Young, D.T.

1982-01-01

Observations of low-energy ionospheric ions by the plasma composition experiment abroad ISEE 1 often show conical pitch angle distributions, that is, peak fluxes between 0 0 and 90 0 to the directions parallel or antiparallel to the magnetic field. Frequently, all three primary ionospheric ion species (H + , He + , and O + ) simultaneously exhibit conical distributions with peak fluxes at essentially the same pitch angle. A distinction is made here between unidirectional, or streaming, distributions, in which ions are traveling essentially from only one hemisphere, and symmetrical distributions, in which significant fluxes are observed traveling from both hemispheres. The orbital coverage for this survey was largely restricted to the night sector, approximately 2100--0600 LT, and moderate geomagnetic latitudes of 20 0 --40 0 . Also, lack of complete pitch angle coverage at all times may have reduced detection for conics with small cone angles. However, we may conclude that the unidirectional conical distributions observed in the northern hemisphere are always observed to be traveling from the northern hemisphere and that they exhibit the following characteristics relative to the symmetric distributions, in that they (1) are typically observed on higher L shells (that is, higher geomagnetic latitudes or larger geocentric distances or both), (2) tend to have significantly larger cone angles, and (3), are associated with higher magnetic activity levels

Enhancement of micro-grid performance during islanding mode using storage batteries and new fuzzy logic pitch angle controller

International Nuclear Information System (INIS)

Kamel, Rashad M.; Chaouachi, A.; Nagasaka, Ken

2011-01-01

Research highlights: → Novel fuzzy pitch angle controller is proposed for smoothing wind fluctuation. → Storage batteries are used for performance improve of MG in islanding mode. → Those new techniques are compared with conventional PI pitch angle controller. -- Abstract: Power system deregulation, shortage of transmission capacities and needing to reduce green house gas have led to increase interesting in distributed generations (DGs) especially renewable sources. This study developed a complete model able to analysis and simulates in details the transient dynamic performance of the Micro-Grid (MG) during and subsequent islanding process. Wind speed fluctuations cause high fluctuations in output power of wind turbine which lead to fluctuations of frequency and voltages of the MG during the islanding mode. In this paper a new fuzzy logic pitch angle controller is proposed to smooth the output power of wind turbine to reduce MG frequency and voltage fluctuations during the islanding mode. The proposed fuzzy logic pitch controller is compared with the conventional PI pitch angle controller which usually used for wind turbine power control. Results proved the effectiveness of the proposed fuzzy controller in improvement of the MG performance. Also, this paper proposed using storage batteries technique to reduce the frequency deviation and fluctuations originated from wind power solar power fluctuations. Results indicate that the storage batteries technique is superior than fuzzy logic pitch controller in reducing frequency deviation, but with more expensive than the fuzzy controller. All models and controllers are built using Matlab (registered) Simulink (registered) environment.

Pitch angle scattering of an energetic magnetized particle by a circularly polarized electromagnetic wave

International Nuclear Information System (INIS)

Bellan, P. M.

2013-01-01

The interaction between a circularly polarized wave and an energetic gyrating particle is described using a relativistic pseudo-potential that is a function of the frequency mismatch. Analysis of the pseudo-potential provides a means for interpreting numerical results. The pseudo-potential profile depends on the initial mismatch, the normalized wave amplitude, and the initial angle between the wave magnetic field and the particle perpendicular velocity. For zero initial mismatch, the pseudo-potential consists of only one valley, but for finite mismatch, there can be two valleys separated by a hill. A large pitch angle scattering of the energetic electron can occur in the two-valley situation but fast scattering can also occur in a single valley. Examples relevant to magnetospheric whistler waves show that the energetic electron pitch angle can be deflected 5°towards the loss cone when transiting a 10 ms long coherent wave packet having realistic parameters.

Multi-Layer Artificial Neural Networks Based MPPT-Pitch Angle Control of a Tidal Stream Generator

Directory of Open Access Journals (Sweden)

Khaoula Ghefiri

2018-04-01

Full Text Available Artificial intelligence technologies are widely investigated as a promising technique for tackling complex and ill-defined problems. In this context, artificial neural networks methodology has been considered as an effective tool to handle renewable energy systems. Thereby, the use of Tidal Stream Generator (TSG systems aim to provide clean and reliable electrical power. However, the power captured from tidal currents is highly disturbed due to the swell effect and the periodicity of the tidal current phenomenon. In order to improve the quality of the generated power, this paper focuses on the power smoothing control. For this purpose, a novel Artificial Neural Network (ANN is investigated and implemented to provide the proper rotational speed reference and the blade pitch angle. The ANN supervisor adequately switches the system in variable speed and power limitation modes. In order to recover the maximum power from the tides, a rotational speed control is applied to the rotor side converter following the Maximum Power Point Tracking (MPPT generated from the ANN block. In case of strong tidal currents, a pitch angle control is set based on the ANN approach to keep the system operating within safe limits. Two study cases were performed to test the performance of the output power. Simulation results demonstrate that the implemented control strategies achieve a smoothed generated power in the case of swell disturbances.

Particle pitch angle diffusion due to nonadiabatic effects in the plasma sheet

International Nuclear Information System (INIS)

Gray, P.C.; Lee, L.C.

1982-01-01

In order to understand certain aspects of the plasma sheet dynamics, a numerical study of the nonadiabatic behavior of particles in a model field geometry is performed. The particle's magnetic moment as a function of time is calculated for various initial parameters, corresponding to various particle energies and degrees of field curvature. It is shown that the magnetic moment changes as the particle passes through the plasma sheet and that the magnitude of the change is related to the curvature of the field at the middle of the plasma sheet. The relation of the magnitude of the change in magnetic moment to the particle's pitch and phase angles as it passes through the sheet is numerically resolved. The nature of the change may be considered as a mechanism for pitch angle diffusion, and the diffusion coefficient is calculated. This scattering mechanism is significant for plasma sheet ions (1--10 keV) as well as energetic electrons (>100 keV)

Magnetic field pitch angle diagnostic using the motional Stark effect (invited)

International Nuclear Information System (INIS)

Levinton, F.M.; Gammel, G.M.; Kaita, R.; Kugel, H.W.; Roberts, D.W.

1990-01-01

The Stark effect has been employed in a novel technique for obtaining the pitch angle profile and q(r) using polarimetry measurements of the Doppler shifted H α emission from a hydrogen diagnostic neutral beam. As a neutral beam propagates through a plasma, collisions of the beam particles with the background ions and electrons will excite beam atoms, leading to emission of radiation. The motional Stark effect, which arises from the electric field induced in the atom's rest frame due to the beam motion across the magnetic field (E=V beam xB), causes a wavelength splitting of several angstroms and polarization of the emitted radiation. The Δm=±1 transitions, or σ components, from the beam fluorescence are linearly polarized parallel to the direction of the local magnetic field when viewed transverse to the fields. Since the hydrogen beam provides good spatial localization and penetration, the pitch angle can be obtained anywhere in the plasma. A photoelastic modulator (PEM) is used to modulate the linearly polarized light. Depending on the orientation of the PEM, it can measure the sine or cosine of the angle of polarization. Two PEM's are used to measure both components simultaneously. Results of q(r) for both Ohmic and NBI heated discharges have been obtained in the Princeton Beta Experiment (PBX-M) tokamak, with an uncertainty of ∼6% for q(0)

Pitch angle scattering in three-dimensional "critical balance" MHD turbulence.

Science.gov (United States)

Forman, Miriam; Oughton, Sean; Horbury, Tim

2004-11-01

We calculated the dependence of the quasi-linear particle pitch angle scattering coefficient in general 3-dimensional turbulence axi-symmetric about the mean magnetic field. We integrate over the power spectrum tensor of the turbulence in terms of the scalar functions E, F, C, and H of the wavevector k, as described by Oughton, et al. for incompressible MHD. The application to a "slab+ 2.5D" model is trivial, and reproduces Bieber, et al.'s extremely important previous result that the 2.5D part does not do any pitch-angle scattering. However, the "slab + 2D" is a highly idealized model. One wonders how its two parts are related to actual turbulence, as observed in space or in simulations, and to the calculation of the particle scattering. Here we update the "slab + 2D" model to a more realistic distribution in k-space, specifically a modification of the inertial-range "critical balance" form introduced by Goldreich and Sridhar, and developed further by Cho, Lazarian and Vishniac. We apply the 3D quasi-linear method to calculate D and the spatial diffusion coefficient parallel to the local mean magnetic field, in the "critical balance" anisotropic turbulence. We thank the International Space Science Institute (Bern, Switzerland) for support of this work.

Further evidence for a supermassive black hole mass-pitch angle relation

Energy Technology Data Exchange (ETDEWEB)

Berrier, Joel C.; Kennefick, Daniel; Kennefick, Julia D.; Hartley, Matthew; Lacy, Claud H. S. [Department of Physics, University of Arkansas, 825 West Dickson Street, Fayetteville, AR 72701 (United States); Davis, Benjamin L.; Barrows, Robert Scott; Shields, Doug [Arkansas Center for Space and Planetary Sciences, University of Arkansas, 202 Old Field House, Fayetteville, AR 72701 (United States); Seigar, Marc S. [Department of Physics and Astronomy, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Bentz, Misty C. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)

2013-06-01

We present new and stronger evidence for a previously reported relationship between galactic spiral arm pitch angle P (a measure of the tightness of spiral structure) and the mass M {sub BH} of a disk galaxy's nuclear supermassive black hole (SMBH). We use an improved method to accurately measure the spiral arm pitch angle in disk galaxies to generate quantitative data on this morphological feature for 34 galaxies with directly measured black hole masses. We find a relation of log (M/M {sub ☉}) = (8.21 ± 0.16) – (0.062 ± 0.009)P. This method is compared with other means of estimating black hole mass to determine its effectiveness and usefulness relative to other existing relations. We argue that such a relationship is predicted by leading theories of spiral structure in disk galaxies, including the density wave theory. We propose this relationship as a tool for estimating SMBH masses in disk galaxies. This tool is potentially superior when compared to other methods for this class of galaxy and has the advantage of being unambiguously measurable from imaging data alone.

Pitch angle distributions of > 30 keV electrons at geostationary altitudes

International Nuclear Information System (INIS)

Higbie, P.R.; Baker, D.N.; Hones, E.W. Jr.; Belian, R.D.

1978-01-01

The satellites 1976-059A and 1977-007A each carry energetic particle detectors which measure fluxes of electrons in the 30 to 300 keV energy range. Five separate sensors mounted at 30, 60, 90, 120, and 150 0 to the spacecraft spin axis provide two hundred samples of the three dimensional distribution function for every ten second spacecraft rotation. Spherical harmonic functions up to the fourth order were fit to the observed pitch angle distributions. The second and fourth order coefficients obtained for these fits were averaged for each hour of local time. The probability distributions for the averaged harmonic coefficients were calculated and are presented as a function of local time. Possible relations of these distributions to interplanetary conditions are discussed. Using the present analysis techniques, the intensity of electrons at the noon meridian is derived as a function of pitch angle and radial distance and is given by j(α,r) = 2.03 x 10 8 (0.49 sin 4 . 78 α + 0.51 sin 0 . 27 α) e/sup -r/1.60/ el/cm 2 sec sr. 11 references

Statistical study of ion pitch-angle distributions

International Nuclear Information System (INIS)

Sibeck, D.G.; Mcentire, R.W.; Lui, A.T.Y.; Krimigis, S.M.

1987-01-01

Preliminary results of a statistical study of energetic (34-50 keV) ion pitch-angle distributions (PADs) within 9 Re of earth provide evidence for an orderly pattern consistent with both drift-shell splitting and magnetopause shadowing. Normal ion PADs dominate the dayside and inner magnetosphere. Butterfly PADs typically occur in a narrow belt stretching from dusk to dawn through midnight, where they approach within 6 Re of earth. While those ion butterfly PADs that typically occur on closed drift paths are mainly caused by drift-shell splitting, there is also evidence for magnetopause shadowing in observations of more frequent butterfly PAD occurrence in the outer magnetosphere near dawn than dusk. Isotropic and gradient boundary PADs terminate the tailward extent of the butterfly ion PAD belt. 9 references

Pitch angle scattering of relativistic electrons from stationary magnetic waves: Continuous Markov process and quasilinear theory

International Nuclear Information System (INIS)

Lemons, Don S.

2012-01-01

We develop a Markov process theory of charged particle scattering from stationary, transverse, magnetic waves. We examine approximations that lead to quasilinear theory, in particular the resonant diffusion approximation. We find that, when appropriate, the resonant diffusion approximation simplifies the result of the weak turbulence approximation without significant further restricting the regime of applicability. We also explore a theory generated by expanding drift and diffusion rates in terms of a presumed small correlation time. This small correlation time expansion leads to results valid for relatively small pitch angle and large wave energy density - a regime that may govern pitch angle scattering of high-energy electrons into the geomagnetic loss cone.

HYDRODYNAMICS OF OSCILLATING WING ON THE PITCH ANGLE

Directory of Open Access Journals (Sweden)

Vitalii Korobov

2017-07-01

Full Text Available Purpose: research of the hydrodynamic characteristics of a wing in a nonstationary stream. Methods: The experimental studies of the hydrodynamic load acting on the wing of 1.5 elongation, wich harmonically oscillated respect to the transversal axis in the frequency range of 0.2-2.5 Hz. The flow speed in the hydrodynamic tunnel ranged of 0.2-1.5 m/s. Results: The instantaneous values of the coefficients of lift and drag / thrust on the pitch angle at unsteady flow depends on the Strouhal number.Discussion: with increasing oscillation frequency coefficients of hydrodynamic force components significantly higher than the data for the stationary blowing out of the wing.

Rocket measurements of relativistic electrons: New features in fluxes, spectra and pitch angle distributions

International Nuclear Information System (INIS)

Herrero, F.A.; Baker, D.N.; Goldberg, R.A.

1991-01-01

The authors report new features of precipitating relativistic electron fluxes measured on a spinning sounding rocket payload at midday between altitudes of 70 and 130 km in the auroral region (Poker Flat, Alaska, 65.1 degree N, 147.5 degree W, and L = 5.5). The sounding rocket (NASA 33.059) was launched at 21:29 UT on May 13, 1990 during a relativistic electron enhancement event of modest intensity. Electron fluxes were measured for a total of about 210 seconds at energies from 0.1 to 3.8 MeV, while pitch angle was sampled from 0 degree to 90 degree every spin cycle. Flux levels during the initial 90 seconds were about 5 to 8 times higher than in the next 120 seconds, revealing a time scale of more than 100 seconds for large amplitude intensity variations. A shorter time scale appeared for downward electron bursts lasting 10 to 20 seconds. Electrons with energies below about 0.2 MeV showed isotropic pitch angle distributions during most of the first 90 seconds of data, while at higher energies the electrons had highest fluxes near the mirroring angle (90 degree); when they occurred, the noted downward bursts were seen at all energies. Data obtained during the second half of the flight showed little variation in the shape of the pitch angle distribution for energies greater than 0.5 MeV; the flux at 90 degree was about 100 times the flux at 0 degree. They have compared the low altitude fluxes with those measured at geostationary orbit (L = 6.6), and find that the low altitude fluxes are much higher than expected from a simple mapping of a pancake distribution at high altitudes (at the equator). Energy deposition of this modest event is estimated to increase rapidly above 45 km, already exceeding the cosmic ray background at 45 km

Pitch Angle Scattering of Upgoing Electron Beams in Jupiter's Polar Regions by Whistler Mode Waves

Science.gov (United States)

Elliott, S. S.; Gurnett, D. A.; Kurth, W. S.; Clark, G.; Mauk, B. H.; Bolton, S. J.; Connerney, J. E. P.; Levin, S. M.

2018-02-01

The Juno spacecraft's Jupiter Energetic-particle Detector Instrument has observed field-aligned, unidirectional (upgoing) electron beams throughout most of Jupiter's entire polar cap region. The Waves instrument detected intense broadband whistler mode emissions occurring in the same region. In this paper, we investigate the pitch angle scattering of the upgoing electron beams due to interactions with the whistler mode waves. Profiles of intensity versus pitch angle for electron beams ranging from 2.53 to 7.22 Jovian radii show inconsistencies with the expected adiabatic invariant motion of the electrons. It is believed that the observed whistler mode waves perturb the electron motion and scatter them away from the magnetic field line. The diffusion equation has been solved by using diffusion coefficients which depend on the magnetic intensity of the whistler mode waves.

Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

Directory of Open Access Journals (Sweden)

Yanzhao Yang

2018-06-01

Full Text Available The blade pitch angle has a significant influence on the aerodynamic characteristics of horizontal axis wind turbines. However, few research results have revealed its impact on the straight-bladed vertical axis wind turbine (Sb-VAWT. In this paper, wind tunnel experiments and CFD simulations were performed at the Sb-VAWT to investigate the effect of different blade pitch angles on the pressure distribution on the blade surface, the torque coefficient, and the power coefficient. In this study, the airfoil type was NACA0021 with two blades. The Sb-VAWT had a rotor radius of 1.0 m with a spanwise length of 1.2 m. The simulations were based on the k-ω Shear Stress Transport (SST turbulence model and the wind tunnel experiments were carried out using a high-speed multiport pressure device. As a result, it was found that the maximum pressure difference on the blade surface was obtained at the blade pitch angle of β = 6° in the upstream region. However, the maximum pressure coefficient was shown at the blade pitch angle of β = 8° in the downstream region. The torque coefficient acting on a single blade reached its maximum value at the blade pitch angle of β = 6°. As the tip speed ratio increased, the power coefficient became higher and reached the optimum level. Subsequently, further increase of the tip speed ratio only led to a quick reversion of the power coefficient. In addition, the results from CFD simulations had also a good agreement with the results from the wind tunnel experiments. As a result, the blade pitch angle did not have a significant influence on the aerodynamic characteristics of the Sb-VAWT.

Pitch control margin at high angle of attack - Quantitative requirements (flight test correlation with simulation predictions)

Science.gov (United States)

Lackey, J.; Hadfield, C.

1992-01-01

Recent mishaps and incidents on Class IV aircraft have shown a need for establishing quantitative longitudinal high angle of attack (AOA) pitch control margin design guidelines for future aircraft. NASA Langley Research Center has conducted a series of simulation tests to define these design guidelines. Flight test results have confirmed the simulation studies in that pilot rating of high AOA nose-down recoveries were based on the short-term response interval in the forms of pitch acceleration and rate.

Computational investigation of heat transfer and pressure drop in a typical louver fin-and-tube heat exchanger for various louver angles and fin pitches

Directory of Open Access Journals (Sweden)

Okbaz Abdulkerim

2017-01-01

Full Text Available In this study 3-D numerical simulations on heat transfer and pressure drop characteristics for a typical louver fin-and- double-row tube heat exchanger were carried out. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles, fin pitch and Reynolds number, and reported in terms of Colburn j-factor and Fanning friction factor f. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles between 20° ≤Ө≤ 30°, louver pitch of Lp=3.8 mm and frontal velocities of U between 1.22 m/s - 3 m/s. In addition, flow visualization of detailed flow features results, such as velocity vectors, streamlines and temperature counters have been shown to understand heat transfer enhancement mechanism. The present results indicated that louver angle and fin pitch noticeably affected the thermal and hydraulic performance of heat exchanger. It has been seen that increasing louver angle, increases thermal performance while decreasing hydraulic performance associated to pressure drop for fin pitches of 3.2 mm and 2.5 mm. Fin pitch determines the flow behaviour that for fin pitch of 2 mm, increasing louver angle decreased heat transfer and pressure drop. Velocity vectors and streamlines give considerable information about the flow whether it is duct directed or louver directed. For all conditions the flow is louver directed.

Adaptive pitch control for variable speed wind turbines

Science.gov (United States)

Johnson, Kathryn E [Boulder, CO; Fingersh, Lee Jay [Westminster, CO

2012-05-08

An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

Banded Structures in Electron Pitch Angle Diffusion Coefficients from Resonant Wave Particle Interactions

Science.gov (United States)

Tripathi, A. K.; Singhal, R. P.; Khazanov, G. V.; Avanov, L. A.

2016-01-01

Electron pitch angle (D (alpha)) and momentum (D(pp)) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L = 4.6 and 6.8 for electron energies 10 keV. Landau (n = 0) resonance and cyclotron harmonic resonances n = +/-1, +/-2,...+/-5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (alpha) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n = +1 and n = +2. A major contribution to momentum diffusion coefficients appears from n = +2. However, the banded structures in D alpha and Dpp coefficients appear only in the profile of diffusion coefficients for n = +2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The Dpp diffusion coefficient for ECH waves is one to two orders smaller than D alpha coefficients. For chorus waves, Dpp coefficients are about an order of magnitude smaller than D alpha coefficients for the case n does not = 0. In case of Landau resonance, the values of Dpp coefficient are generally larger than the values of D alpha coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89 deg and harmonic resonances n = +1, +2, and +3, whereas for whistler mode waves, the frequencies have been calculated for angle

Magnetic field pitch angle and perpendicular velocity measurements from multi-point time-delay estimation of poloidal correlation reflectometry

Science.gov (United States)

Prisiazhniuk, D.; Krämer-Flecken, A.; Conway, G. D.; Happel, T.; Lebschy, A.; Manz, P.; Nikolaeva, V.; Stroth, U.; the ASDEX Upgrade Team

2017-02-01

In fusion machines, turbulent eddies are expected to be aligned with the direction of the magnetic field lines and to propagate in the perpendicular direction. Time delay measurements of density fluctuations can be used to calculate the magnetic field pitch angle α and perpendicular velocity {{v}\\bot} profiles. The method is applied to poloidal correlation reflectometry installed at ASDEX Upgrade and TEXTOR, which measure density fluctuations from poloidally and toroidally separated antennas. Validation of the method is achieved by comparing the perpendicular velocity (composed of the E× B drift and the phase velocity of turbulence {{v}\\bot}={{v}E× B}+{{v}\\text{ph}} ) with Doppler reflectometry measurements and with neoclassical {{v}E× B} calculations. An important condition for the application of the method is the presence of turbulence with a sufficiently long decorrelation time. It is shown that at the shear layer the decorrelation time is reduced, limiting the application of the method. The magnetic field pitch angle measured by this method shows the expected dependence on the magnetic field, plasma current and radial position. The profile of the pitch angle reproduces the expected shape and values. However, comparison with the equilibrium reconstruction code cliste suggests an additional inclination of turbulent eddies at the pedestal position (2-3°). This additional angle decreases towards the core and at the edge.

Output Power Control of Wind Turbine Generator by Pitch Angle Control using Minimum Variance Control

Science.gov (United States)

Senjyu, Tomonobu; Sakamoto, Ryosei; Urasaki, Naomitsu; Higa, Hiroki; Uezato, Katsumi; Funabashi, Toshihisa

In recent years, there have been problems such as exhaustion of fossil fuels, e. g., coal and oil, and environmental pollution resulting from consumption. Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuel. Wind energy is not constant and windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of blades of the windmill. In this paper, output power leveling of wind turbine generator by pitch angle control using an adaptive control is proposed. A self-tuning regulator is used in adaptive control. The control input is determined by the minimum variance control. It is possible to compensate control input to alleviate generating power fluctuation with using proposed controller. The simulation results with using actual detailed model for wind power system show effectiveness of the proposed controller.

Banded Structures in Electron Pitch Angle Diffusion Coefficients from Resonant Wave-Particle Interactions

Science.gov (United States)

Tripathi, A. K.; Singhal, R. P.; Khazanov, G. V.; Avanov, L. A.

2016-01-01

Electron pitch angle (D(sub (alpha alpha))) and momentum (D(sub pp)) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L=4.6 and 6.8 for electron energies less than or equal to 10 keV. Landau (n=0) resonance and cyclotron harmonic resonances n= +/- 1, +/-2, ... +/-5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (alpha) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n=+1 and n=+2. A major contribution to momentum diffusion coefficients appears from n=+2. However, the banded structures in D(sub alpha alpha) and D(sub pp) coefficients appear only in the profile of diffusion coefficients for n=+2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The D(sub pp) diffusion coefficient for ECH waves is one to two orders smaller than D(sub alpha alpha) coefficients. For chorus waves, D(sub pp) coefficients are about an order of magnitude smaller than D(sub alpha alpha) coefficients for the case n does not equal 0. In case of Landau resonance, the values of D(sub pp) coefficient are generally larger than the values of D(sub alpha alpha) coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89 deg and harmonic resonances

Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering in Outer RB

Science.gov (United States)

Khazanov, G. V.; Gamayunov, K. V.

2007-01-01

We present the equatorial and bounce average pitch angle diffusion coefficients for scattering of relativistic electrons by the H+ mode of EMIC waves. Both the model (prescribed) and self consistent distributions over the wave normal angle are considered. The main results of our calculation can be summarized as follows: First, in comparison with field aligned waves, the intermediate and highly oblique waves reduce the pitch angle range subject to diffusion, and strongly suppress the scattering rate for low energy electrons (E less than 2 MeV). Second, for electron energies greater than 5 MeV, the |n| = 1 resonances operate only in a narrow region at large pitch-angles, and despite their greatest contribution in case of field aligned waves, cannot cause electron diffusion into the loss cone. For those energies, oblique waves at |n| greater than 1 resonances are more effective, extending the range of pitch angle diffusion down to the loss cone boundary, and increasing diffusion at small pitch angles by orders of magnitude.

Myosin helical pitch angle as a quantitative imaging biomarker for characterization of cardiac programming in fetal growth restriction measured by polarization second harmonic microscopy

Science.gov (United States)

Amat-Roldan, I.; Psilodimitrakopoulos, S.,; Eixarch, E.,; Torre, I.; Wotjas, B.; Crispi, F.; Figueras, F.; Artigas, D.,; Loza-Alvarez, P.; Gratacos, E.,

2009-07-01

Fetal growth restriction (FGR) has recently shown a strong association with cardiac programming which predisposes to cardiovascular mortality in adulthood. Polarization Second Harmonic Microscopy can quantify molecular architecture changes with high sensitivity in cardiac myofibrils. In this work, we use myosin helical pitch angle as an example to quantify such alterations related to this high risk population. Importantly, this shows a potential use of the technique as an early diagnostic tool and an alternative method to understand pathophysiological processes.

Roll and pitch set-up errors during volumetric modulated arc delivery: can adapting gantry and collimator angles compensate?

Science.gov (United States)

Hoffmans-Holtzer, Nienke A; Hoffmans, Daan; Dahele, Max; Slotman, Ben J; Verbakel, Wilko F A R

2015-03-01

The purpose of this work was to investigate whether adapting gantry and collimator angles can compensate for roll and pitch setup errors during volumetric modulated arc therapy (VMAT) delivery. Previously delivered clinical plans for locally advanced head-and-neck (H&N) cancer (n = 5), localized prostate cancer (n = 2), and whole brain with simultaneous integrated boost to 5 metastases (WB + 5M, n = 1) were used for this study. Known rigid rotations were introduced in the planning CT scans. To compensate for these, in-house software was used to adapt gantry and collimator angles in the plan. Doses to planning target volumes (PTV) and critical organs at risk (OAR) were calculated with and without compensation and compared with the original clinical plan. Measurements in the sagittal plane in a polystyrene phantom using radiochromic film were compared by gamma (γ) evaluation for 2 H&N cancer patients. For H&N plans, the introduction of 2°-roll and 3°-pitch rotations reduced mean PTV coverage from 98.7 to 96.3%. This improved to 98.1% with gantry and collimator compensation. For prostate plans respective figures were 98.4, 97.5, and 98.4%. For WB + 5M, compensation worked less well, especially for smaller volumes and volumes farther from the isocenter. Mean comparative γ evaluation (3%, 1 mm) between original and pitched plans resulted in 86% γ plan restored the mean comparison to 96% γ < 1. Preliminary data suggest that adapting gantry and collimator angles is a promising way to correct roll and pitch set-up errors of < 3° during VMAT for H&N and prostate cancer.

Some thoughts on the Musala anisotropy; pitch angle distribution or what else

International Nuclear Information System (INIS)

Kota, J.; Somogyi, A.J.

1977-01-01

Based on the results obtained in the Musala experiment and in other anisotropy measurements, an attempt is made to explore the three-dimensional structure of cosmic ray anisotropy in the 10 11 - 107M1 4 eV range. (i) It is investigated whether observtions can be reconcilied with a pitch angle distribution. (ii) Assuming that the principal axes of the tensor anisotropy are known, the vector and tensor anisotropies are separated. Discussed are the theoretical implications of the results obtained and possible origins of the second harmonic. (author)

Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event

Science.gov (United States)

Zhang, X.-J.; Li, W.; Thorne, R. M.; Angelopoulos, V.; Ma, Q.; Li, J.; Bortnik, J.; Nishimura, Y.; Chen, L.; Baker, D. N.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Blake, J. B.; Fennell, J. F.

2016-09-01

Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed by Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, the phase space density of ultrarelativistic (>1 MeV) electrons was depleted by more than 1 order of magnitude over the entire radial extent of the outer radiation belt (3 pitch angle distribution under a compressed magnetic field topology based on actual solar wind conditions. Although these ultrarelativistic electrons exhibit highly anisotropic (peaked in 90°), energy-dependent pitch angle distributions, which appear to be associated with the typical EMIC wave scattering, comparison of the modeled electron distribution to electron measurements indicates that drift shell splitting is responsible for this rapid change in electron pitch angle distributions. This further indicates that magnetopause loss is the predominant cause of the electron dropout right after the shock arrival.

Unsteady force characteristics on foils undergoing pitching motion

International Nuclear Information System (INIS)

Yang, Chang Jo

2006-01-01

In the present study the unsteady forces acting on the pitching foils such as a flat plate, NACA0010, NACA0020, NACA65-0910 and BTE have been measured by using a six-axis sensor in a circulating water tunnel at a low Reynolds number region. The unsteady characteristics of the dynamic drag and lift have been compared to the quasi-steady ones which are measured under the stationary condition. The pitching motion is available for keeping the lift higher after the separation occurs. Especially, the characteristics of the dynamic lift are quite different from the quasi-steady one at high pitching frequency regions. As the pitching frequency deceases, the amplitude of the dynamic lift becomes closer to the quasi-steady one. However, the phase remains different between the steady and unsteady conditions even at low pitching frequencies. On the other hand, the dynamic drag is governed strongly by the angle of attack

Design and Pitch Angle Optimisation of Horizontal Axis Hydrokinetic Turbine with Constant Tip Speed Ratio

Directory of Open Access Journals (Sweden)

Nigam Suyash

2017-01-01

Full Text Available Booming population and associated energy demands, looming threat of exhaustion of conventional sources of energy and the severe environmental repercussions of the same call for alternate sources of clean energy. Hydrokinetic turbine is one such developing technology which harnesses zero-head free flow of water and affects hydrological ecology minimally. This paper discusses the optimisation of Horizontal Axis Hydrokinetic Turbine (HAHkT blade chord length and twist angle using blade element momentum (BEM theory to achieve a constant optimal angle of attack (AoA, thus maximising the power output. To achieve this while maintaining robustness at the hub end and eliminate cavitation, two different hydrofoils (S832 and E817 are selected. S832 is simulated using ANSYS 14.0 at low (00 and high (150 angles of attack and compared against more widely used NACA 4412 to study flow separation characteristics. This is followed by calculating angles of relative flow, ratios of chord length and subsequently twist angles for each blade element using MATLAB simulations. A blade model is thus developed for visualisation using computer aided designing after obtaining optimal chord lengths and pitch angles.

Adjoint-Baed Optimal Control on the Pitch Angle of a Single-Bladed Vertical-Axis Wind Turbine

Science.gov (United States)

Tsai, Hsieh-Chen; Colonius, Tim

2017-11-01

Optimal control on the pitch angle of a NACA0018 single-bladed vertical-axis wind turbine (VAWT) is numerically investigated at a low Reynolds number of 1500. With fixed tip-speed ratio, the input power is minimized and mean tangential force is maximized over a specific time horizon. The immersed boundary method is used to simulate the two-dimensional, incompressible flow around a horizontal cross section of the VAWT. The problem is formulated as a PDE constrained optimization problem and an iterative solution is obtained using adjoint-based conjugate gradient methods. By the end of the longest control horizon examined, two controls end up with time-invariant pitch angles of about the same magnitude but with the opposite signs. The results show that both cases lead to a reduction in the input power but not necessarily an enhancement in the mean tangential force. These reductions in input power are due to the removal of a power-damaging phenomenon that occurs when a vortex pair is captured by the blade in the upwind-half region of a cycle. This project was supported by Caltech FLOWE center/Gordon and Betty Moore Foundation.

Characteristics of pitch angle distributions of hundreds of keV electrons in the slot region and inner radiation belt

Science.gov (United States)

Zhao, H.; Li, X.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D. M.

2014-12-01

The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-the-art pitch angle-resolved data from the Magnetic Electron Ion Spectrometer instrument onboard the Van Allen Probes, a detailed analysis of hundreds of keV electron PADs below L = 4 is performed, in which the PADs are categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°), and 90° minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of ˜460 keV electrons for over a year, we find that the 90° minimum PADs are generally present in the inner belt (Lpitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L = 3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2 mechanism can hardly explain the formation of 90° minimum PADs at the center of inner belt.

H-Darrieus Wind Turbine with Blade Pitch Control

Directory of Open Access Journals (Sweden)

I. Paraschivoiu

2009-01-01

Full Text Available A procedure for computing the optimal variation of the blades' pitch angle of an H-Darrieus wind turbine that maximizes its torque at given operational conditions is proposed and presented along with the results obtained on a 7 kW prototype. The CARDAAV code, based on the “Double-Multiple Streamtube” model developed by the first author, is used to determine the performances of the straight-bladed vertical axis wind turbine. This was coupled with a genetic algorithm optimizer. The azimuthal variation of the blades' pitch angle is modeled with an analytical function whose coefficients are used as variables in the optimization process. Two types of variations were considered for the pitch angle: a simple sinusoidal one and one which is more general, relating closely the blades' pitch to the local flow conditions along their circular path. A gain of almost 30% in the annual energy production was obtained with the polynomial optimal pitch control.

Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations

Science.gov (United States)

Wang, Kaiti; Lin, Ching-Huei; Wang, Lu-Yin; Hada, Tohru; Nishimura, Yukitoshi; Turner, Drew L.; Angelopoulos, Vassilis

2014-12-01

Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty-two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar-type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar-type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model-calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.

Effects of spray axis incident angle on heat transfer performance of rhombus-pitch shell-and-tube interior spray evaporator

International Nuclear Information System (INIS)

Lin, Ru-Li; Chang, Tong-Bou; Liang, Chih-Chang

2012-01-01

An interior spray method is proposed for enhancing the heat transfer performance of a compact rhombus-pitch shell-and-tube spray evaporator. The experimental results show that the shell-side heat transfer coefficient obtained using the proposed spray method is significantly higher than that achieved in a conventional flooded-type evaporator. Four different spray axis incident angles (0 .deg., 45 .deg., 60 .deg. and 75 .deg.) are tested in order to investigate the effect of the spray inclination angle on the heat transfer performance of the spray evaporator system. It is shown that the optimal heat transfer performance is obtained using a spray axis incident angle of 60 .deg.

Electron Pitch Angle Variations Recorded at the High Magnetic Latitude Boundary Layer by the NUADU Instrument on the TC-2 Spacecraft

Science.gov (United States)

Lu, L.; McKenna-Lawlor, S.; Barabash, S.; Liu, Z.; Balaz, J.; Brinkfeldt, K.; Strhansky, I.; Shen, C.; Shi, J.; Cao, J.; Pu, Z.; Fu, S.; Gunell, H.; Kudela, K.; Roelof, E. C.; Brandt, P. C.; Dandouras, I.; Zhang, T.; Carr, C.; Fazakerley, A.

2005-12-01

During the first on orbit commission, with the deflection high voltage zero, the NUADU (NeUtral Atom Detector Unit) instrument aboard TC-2, with its high temporal-spatial resolution recorded 4d solid angle images of energetic particles spiraling around the geomagnetic field lines with different configuration at high northern magnetic latitude L>10. The ambient magnetic field and particles in different energy spectrum were simultaneously measured by the magnetometer experiment (FGM), the plasma electron and current experiment (PEACE), the low energy ion detector (LEID), and the high energy electron detector (HEED). The up-flowing electron beams made the pitch angle distribution (PAD) ring like configuration, and even concentrated toward the field lines to form a dumbbell-type PAD. In integration of the variations of ambient magnetic field and particles in different energy spectrums, a temporal string magnetic bottle model was proposed which might be formed by the disturbance of the magnetic pulse. Changes in the particle pitch angle diffusion may be associated with electron acceleration along the geomagnetic field lines.

Electron pitch angle variations recorded at the high magnetic latitude boundary layer by the NUADU instrument on the TC-2 spacecraft

Directory of Open Access Journals (Sweden)

L. Lu

2005-11-01

Full Text Available The NUADU (NeUtral Atom Detector Unit experiment aboard TC-2 recorded, with high temporal and spatial resolution, 4π solid angle images of electrons (~50-125 keV spiraling around geomagnetic field lines at high northern magnetic latitudes (L>10, during its in-orbit commissioning phase (September 2004. The ambient magnetic field, as well as electrons in other energy ranges, were simultaneously measured by the TC-2 magnetometer (FGM, the plasma electron and current experiment (PEACE, the low energy ion detector (LEID and the high energy electron detector (HEED. The NUADU data showed that up-flowing electron beams could form "ring-like" and "dumbbell-type" pitch angle distributions (PADs in the region sampled. Changes in these pitch angle distributions due to transient magnetic variations are suggested to have been associated with electron acceleration along the geomagnetic field lines. A nested magnetic bottle configuration that formed due to the propagation towards the Earth of a magnetic pulse, is proposed to have been associated with this process.

Consonance and pitch.

Science.gov (United States)

McLachlan, Neil; Marco, David; Light, Maria; Wilson, Sarah

2013-11-01

To date, no consensus exists in the literature as to theories of consonance and dissonance. Experimental data collected over the last century have raised questions about the dominant theories that are based on frequency relationships between the harmonics of music chords. This study provides experimental evidence that strongly challenges these theories and suggests a new theory of dissonance based on relationships between pitch perception and recognition. Experiment 1 shows that dissonance does not increase with increasing numbers of harmonics in chords as predicted by Helmholtz's (1863/1954) roughness theory, nor does it increase with fewer pitch-matching errors as predicted by Stumpf's (1898) tonal fusion theory. Dissonance was strongly correlated with pitch-matching error for chords, which in turn was reduced by chord familiarity and greater music training. This led to the proposition that long-term memory templates for common chords assist the perception of pitches in chords by providing an estimate of the chord intervals from spectral information. When recognition mechanisms based on these templates fail, the spectral pitch estimate is inconsistent with the period of the waveform, leading to cognitive incongruence and the negative affect of dissonance. The cognitive incongruence theory of dissonance was rigorously tested in Experiment 2, in which nonmusicians were trained to match the pitches of a random selection of 2-pitch chords. After 10 training sessions, they rated the chords they had learned to pitch match as less dissonant than the unlearned chords, irrespective of their tuning, providing strong support for a cognitive mechanism of dissonance. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Limitations of fixed pitch Darrieus hydrokinetic turbines and the challenge of variable pitch

Energy Technology Data Exchange (ETDEWEB)

Kirke, B.K. [Sustainable Energy Centre, University of South Australia, Mawson Lakes, SA 5095 (Australia); Lazauskas, L. [Cyberiad, 25/65 King William Street, Adelaide, SA 5000 (Australia)

2011-03-15

Small Darrieus hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Efficiency improves as size increases, since adequate blade chord Reynolds numbers can be maintained with low solidity. Shaking can be eliminated by using helical blades, or reduced by using multiple blades. Starting torque can be marginally improved by the use of cambered blade profiles but may still be inadequate to overcome drive train friction for self-starting. Variable pitch can generate high starting torque, high efficiency and reduced shaking but active pitch control systems add considerably to complexity and cost, while passive systems must have effective pitch control to achieve higher efficiency than fixed pitch systems. (author)

Characteristics of pitch angle distributions of relativistic electrons under the interaction with Pc5 waves in the inner magnetosphere

Science.gov (United States)

Kamiya, K.; Seki, K.; Saito, S.; Amano, T.; Yoshizumi, M.

2017-12-01

Radial transport of relativistic electrons in the inner magnetosphere has been considered as one of acceleration mechanisms of the outer radiation belt electrons and can be driven by the drift resonance with ULF waves in the Pc5 frequency range. The maximum changes of the electron in the radial distance (L) due to the drift resonance depend on the electron energy, pitch angle, and Pc5 wave structure. Those dependences are expected to form the characteristic pitch angle distributions (PADs) as a function of L and electron energy. In this study, we investigate PADs of relativistic electrons due to the drift resonance with a monochromatic Pc5 wave by using two simulation models of the inner magnetosphere: GEMSIS-Ring Current (RC) and GEMSIS-Radiation Belt (RB) models. The GEMSIS-RB simulations calculate guiding center trajectories of relativistic electrons in electric and magnetic fields obtained from the GEMSIS-RC model, which simulates a monochromatic Pc5 wave propagation in the inner magnetosphere. The results show the characteristic PADs depending on the energy and L, which is explicable with the pitch angle dependence of resonance conditions. At a fixed location, those PADs can change from pancake (90°peaked) to butterfly (two peaks in oblique PAs) distributions as the transport by the monochromatic Pc5 wave progresses. These butterfly distributions are seen in the L range where electrons with lower PAs satisfy the resonance condition. It is also found that the lower PA electron with a fixed magnetic moment can be transported deeper inside because of the PA changes to larger values through the adiabatic transport, which enables them to satisfy the efficient resonance condition in wider L range compared to the 90 degrees PA electrons.

Study on variable pitch strategy in H-type wind turbine considering effect of small angle of attack

DEFF Research Database (Denmark)

Zhao, Zhenzhou; Qian, Siyuan; Shen, Wenzhong

2017-01-01

Variable-pitch (VP) technology is an effective approach to upgrade the aerodynamics of the blade of an H-type vertical-axis wind turbine (VAWT). At present, most of the research efforts are focused on the performance improvement of the azimuth angle owing to the large angle of attack (Ao...... distribution in the swept area of turbine changes from an arched shape of the FP-VAWT into a rectangular shape of the VP-VAWT. At last, an 18.9% growth in power efficiency is achieved. All of the above results confirm that the new VP-technology can effectively improve VAWT performance and also widens...... the highest performance tip speed ratio zone which makes the turbines capable of running with high efficiency in wider zones....

Energy dependent modulation of the ulf ion flux oscillations observed at small pitch angles

International Nuclear Information System (INIS)

Su, S.; Konradi, A.; Fritz, T.A.

1979-01-01

The characteristics of the ultralow frequency oscillations in the ion fluxes observed at small pitch angles by the National Oceanic and Atmospheric Adminstration detector telescopes on board ATS 6 are again examined. The present report concentrates on the dramatic variation of the flux modulations detected in various energy channels during a single event which occurred on February 18, 1975. The wave amplitude is observed to be larger in a higher energy channel with energies from 100 keV to 150 keV and to decrease toward the lower energy channels. The lowest-energy protons (25--33 keV) in general are seldom seen to be oscillating, but in this event they display a low-amplitude oscillation which is 180 0 out of p ase with the adjacent channel. Such energy dependent modulation of the flux oscillation is thought to be a consequence of the wave particle resonant interaction. However, the prediction of the bounce resonant interaction is not consistent with the observations of both the energy dependent variation of the flux amplitudes and a 180 0 change in the oscillation phase in the adjacent low-energy channels that occurred in the February 18, 1975, event. Since the shape of the undisturned particle distribution can also determine the variation of the particle perturbation at various energies, the first-order particle distribution derived in a homogeneous plasma with a uniform magnetic field is examined without any specification of the wave mode. When the average particle distribution during the wave observation is used together with a parallel wave electric field that presumably causes the flux modulation at small pitch angles, a reasonable agreement is found between the variation of flux modulation derived from the slope of the average particle distribution and that from the experimental observation

Signatures of the various regions of the outer magnetosphere in the pitch angle distributions of energetic particles

Energy Technology Data Exchange (ETDEWEB)

West, H.I. Jr.

1978-12-11

An account is given of the obervations of the pitch angle distributions of energetic particles in the near equatorial regions of the Earth's magnetosphere. The emphasis is on relating the observed distributions to the field configuration responsible for the observed effects. The observed effects relate to drift-shell splitting, to the breakdown of adiabatic guiding center motion in regions of sharp field curvature relative to partial gyro radii, to wave-particle interactions, and to moving field configurations. 39 references.

Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event: Drift Shell Splitting on the Dayside

International Nuclear Information System (INIS)

Zhang, X.-J.; University of California, Los Angeles, CA; Li, W.; Boston University, MA; Thorne, R. M.

2016-01-01

Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed by Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, the phase space density of ultrarelativistic (>1MeV) electrons was depleted by more than 1 order of magnitude over the entire radial extent of the outer radiation belt (3 < L* < 5) in less than 6 h after the passage of an interplanetary shock. We model the electron pitch angle distribution under a compressed magnetic field topology based on actual solar wind conditions. Although these ultrarelativistic electrons exhibit highly anisotropic (peaked in 90°), energy-dependent pitch angle distributions, which appear to be associated with the typical EMIC wave scattering, comparison of the modeled electron distribution to electron measurements indicates that drift shell splitting is responsible for this rapid change in electron pitch angle distributions. This further indicates that magnetopause loss is the predominant cause of the electron dropout right after the shock arrival.

Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering

Science.gov (United States)

Gamayunov, K. V.; Khazanov, G. V.

2006-01-01

The flux level of outer-zone relativistic electrons (above 1 MeV) is extremely variable during geomagnetic storms, and controlled by a competition between acceleration and loss. Precipitation of these electrons due to resonant pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves is considered one of the major loss mechanisms. This mechanism was suggested in early theoretical studies more than three decades ago. However, direct experimental evidence of the wave role in relativistic electrons precipitation is difficult to obtain because of lack of concurrent measurements of precipitating electrons at low altitudes and the waves in a magnetically conjugate equatorial region. Recently, the data from balloon-borne X-ray instruments provided indirect but strong evidence on an efficiency of the EMIC wave induced loss for the outer-zone relativistic electrons. These observations stimulated theoretical studies that, particularly, demonstrated that EMIC wave induced pitch-angle diffusion of MeV electrons can operate in the strong diffusion limit and this mechanism can compete with relativistic electron depletion caused by the Dst effect during the initial and main phases of storm. Although an effectiveness of relativistic electron scattering by EMIC waves depends strongly on the wave spectral properties, the most favorable assumptions regarding wave characteristics has been made in all previous theoretical studies. Particularly, only quasi field-aligned EMIC waves have been considered as a driver for relativistic electron loss. At the same time, there is growing experimental and theoretical evidence that these waves can be highly oblique; EMIC wave energy can occupy not only the region of generation, i.e. the region of small wave normal angles, but also the entire wave normal angle region, and even only the region near 90 degrees. The latter can dramatically change he effectiveness of relativistic electron scattering by EMIC waves. In the present study, we

Hybrid intelligent control of PMSG wind generation system using pitch angle control with RBFN

International Nuclear Information System (INIS)

Lin, Whei-Min; Hong, Chih-Ming; Ou, Ting-Chia; Chiu, Tai-Ming

2011-01-01

This paper presents the design of a fuzzy sliding mode loss-minimization control for the speed of a permanent magnet synchronous generator (PMSG) and a high-performance on-line training radial basis function network (RBFN) for the turbine pitch angle control. The back-propagation learning algorithm is used to regulate the RBFN controller. The PMSG speed uses maximum power point tracking below the rated speed, which corresponds to low and high wind speed, and the maximum energy can be captured from the wind. A sliding mode controller with an integral-operation switching surface is designed, in which a fuzzy inference mechanism is utilized to estimate the upper bound of uncertainties. Furthermore, the fuzzy inference mechanism with center adaptation is investigated to estimate the optimal bound of uncertainties.

Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

Directory of Open Access Journals (Sweden)

Mao Wei Chen

Full Text Available In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane. This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

Science.gov (United States)

Chen, Mao Wei; Wu, Jiang Hao; Sun, Mao

2017-01-01

In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane). This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

Based on the electric pitch system of large scale horizontal-axis wind turbines,the blade pitch loads coming mainly from centrifugal force,aerodynamic force and gravity are analyzed,and the calculation models for them are established in this paper.For illustration,a 1.2 MW wind turbine is introduced as a practical sample,and its blade pitch loads from centrifugal force,aerodynamic force and gravity are calculated and analyzed separately and synthetically.The research results showed that in the process of rotor rotating 360o,the fluctuation of blade pitch loads is similar to cosine curve when the rotor rotational speed,in-flow wind speed and pitch angle are constant.Furthermore,the amplitude of blade pitch load presents quite a difference at a different pitch angle.The ways of calculation for blade pitch loads are of the universality,and are helpful for further research of the individual pitch control system.

A fuzzy logic pitch angle controller for power system stabilization

Energy Technology Data Exchange (ETDEWEB)

Jauch, Clemens; Cronin, Tom; Sorensen, Poul [Wind Energy Department, Riso National Laboratory, PO Box 49, DK-4000 Roskilde, (Denmark); Jensen, Birgitte Bak [Institute of Energy Technology, Aalborg University, Pontoppidanstraede 101, DK-9220 Aalborg East, (Denmark)

2006-07-12

In this article the design of a fuzzy logic pitch angle controller for a fixed speed, active-stall wind turbine, which is used for power system stabilization, is presented. The system to be controlled, which is the wind turbine and the power system to which the turbine is connected, is described. The advantages of fuzzy logic control when applied to large-signal control of active-stall wind turbines are outlined. The general steps of the design process for a fuzzy logic controller, including definition of the controller inputs, set-up of the fuzzy rules and the method of defuzzification, are described. The performance of the controller is assessed by simulation, where the wind turbine's task is to dampen power system oscillations. In the scenario simulated for this work, the wind turbine has to ride through a transient short-circuit fault and subsequently contribute to the damping of the grid frequency oscillations that are caused by the transient fault. It is concluded that the fuzzy logic controller enables the wind turbine to dampen power system oscillations. It is also concluded that, owing to the inherent non-linearities in a wind turbine and the unpredictability of the whole system, the fuzzy logic controller is very suitable for this application. (Author).

Hybrid intelligent control of PMSG wind generation system using pitch angle control with RBFN

Energy Technology Data Exchange (ETDEWEB)

Lin, Whei-Min; Hong, Chih-Ming [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 804 (China); Ou, Ting-Chia; Chiu, Tai-Ming [Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan 325 (China)

2011-02-15

This paper presents the design of a fuzzy sliding mode loss-minimization control for the speed of a permanent magnet synchronous generator (PMSG) and a high-performance on-line training radial basis function network (RBFN) for the turbine pitch angle control. The back-propagation learning algorithm is used to regulate the RBFN controller. The PMSG speed uses maximum power point tracking below the rated speed, which corresponds to low and high wind speed, and the maximum energy can be captured from the wind. A sliding mode controller with an integral-operation switching surface is designed, in which a fuzzy inference mechanism is utilized to estimate the upper bound of uncertainties. Furthermore, the fuzzy inference mechanism with center adaptation is investigated to estimate the optimal bound of uncertainties. (author)

Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

Science.gov (United States)

Yang, Chang; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.

2016-08-01

Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. Here we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. These results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

International Nuclear Information System (INIS)

Yang, Chang; Changsha University of Science and Technology, Changsha; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan

2016-01-01

Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. In this paper, we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. Finally, these results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

Electron Pitch-Angle Distribution in Pressure Balance Structures Measured by Ulysses/SWOOPS

Science.gov (United States)

Yamauchi, Yohei; Suess, Steven T.; Sakurai, Takashi; Six, N. Frank (Technical Monitor)

2002-01-01

Pressure balance structures (PBSs) are a common feature in the high-latitude solar wind near solar minimum. From previous studies, PBSs are believed to be remnants of coronal plumes. Yamauchi et al [2002] investigated the magnetic structures of the PBSs, applying a minimum variance analysis to Ulysses/Magnetometer data. They found that PBSs contain structures like current sheets or plasmoids, and suggested that PBSs are associated with network activity such as magnetic reconnection in the photosphere at the base of polar plumes. We have investigated energetic electron data from Ulysses/SWOOPS to see whether bi-directional electron flow exists and we have found evidence supporting the earlier conclusions. We find that 45 ot of 53 PBSs show local bi-directional or isotopic electron flux or flux associated with current-sheet structure. Only five events show the pitch-angle distribution expected for Alfvenic fluctuations. We conclude that PBSs do contain magnetic structures such as current sheets or plasmoids that are expected as a result of network activity at the base of polar plumes.

Intelligent control for large-scale variable speed variable pitch wind turbines

Institute of Scientific and Technical Information of China (English)

Xinfang ZHANG; Daping XU; Yibing LIU

2004-01-01

Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances.Automatic control is crucial for the efficiency and reliability of wind turbines.On the basis of simplified and proper model of variable speed variable pitch wind turbines,the effective wind speed is estimated using extended Kalman filter.Intelligent control schemes proposed in the paper include two loops which operate in synchronism with each other.At below-rated wind speed,the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture.At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power.The simulation shows the effectiveness of the intelligent control.

Evaluation of dose delivery accuracy due to variation in pitch and roll

Energy Technology Data Exchange (ETDEWEB)

Jeong, Chang Young; Bae, Sun Myung; Lee, Dong Hyung; Min, Soon Ki; Kang, Tae Young; Baek, Geum Mun [Dept. of Radiation Oncology, ASAN Medical Center, Seoul (Korea, Republic of)

2014-12-15

The purpose of this study is to verify the accuracy of dose delivery according to the pitch and roll rotational setup error with 6D robotic couch in Intensity Modulated Radiation Therapy ( IMRT ) for pelvic region in patients. Trilogy(Varian, USA) and 6D robotic couch(ProturaTM 1.4, CIVCO, USA) were used to measure and analyze the rotational setup error of 14 patients (157 setup cases) for pelvic region. The total 157 Images(CBCT 78, Radiography 79) were used to calculate the mean value and the incidence of pitch and roll rotational setup error with Microsoft Office Excel 2007. The measured data (3 mm, 3%) at the reference angle (0 °) without couch rotation of pitch and roll direction was compared to the others at different pitch and roll angles (1 °, 1.5 °, 2 °, 2.5 °) to verify the accuracy of dose delivery by using 2D array ionization chamber (I'mRT Matrixx, IBA Dosimetry, Germany) and MultiCube Phantom(IBA Dosimetry, Germany). Result from the data, gamma index was evaluated. The mean values of pitch and roll rotational setup error were 0.9±0.7 °, 0.5±0.6 °. The maximum values of them were 2.8 °, 2.0 °. All of the minimum values were zero. The mean values of gamma pass rate at four different pitch angles (1 °, 1.5 °, 2 °, 2.5 °) were 97.75%, 96.65%, 94.38% and 90.91%. The mean values of gamma pass rate at four different roll angles (1 °, 1.5 °, 2 °, 2.5 °) were 93.68%, 93.05%, 87.77% and 84.96%. when the same angles (1 °, 1.5 °, 2 ° ) of pitch and roll were applied simultaneously, The mean values of each angle were 94.90%, 92.37% and 87.88%, respectively. As a result of this study, it was able to recognize that the accuracy of dose delivered is lowered gradually as pitch and roll increases. In order to increase the accuracy of delivered dose, therefore, it is recommended to perform IGRT or correct patient's position in the pitch and roll direction, to improve the quality of treatment.

A case study on optimum tip speed ratio and pitch angle laws for wind turbine rotors operating in yawed conditions

International Nuclear Information System (INIS)

Cuerva-Tejero, A; Lopez-Garcia, O; González-Meruelo, F; Marangoni, D

2014-01-01

The values of the tip speed ratio and blade pitch angle that yield maximum power coefficient are calculated for a rotor operating in yawed conditions. In a first step, the power coefficient is determined using a model based on the blade element momentum theory (BEMT) which includes a Prandtl-Glauert root-tip losses correction, a non-uniform model for the axial and tangential induction factors, and a model of the rotational augmentation effects. The BEMT model is validated with the experimental data from the NREL-UAE. The maximum values of the power coefficient are determined for different yaw angles and the corresponding values of the tip speed ratio and blade control angle are obtained. The maximum power coefficient using these optimum laws is compared to the maximum power coefficient using the optimum laws of the non-yawed case and it is shown that there is a gain in the power coefficient. For the case study presented in this paper it has been found that for yaw angles of 30° about 10% of the power coefficient can be recovered

A case study on optimum tip speed ratio and pitch angle laws for wind turbine rotors operating in yawed conditions

Science.gov (United States)

Cuerva-Tejero, A.; Lopez-Garcia, O.; Marangoni, D.; González-Meruelo, F.

2014-12-01

The values of the tip speed ratio and blade pitch angle that yield maximum power coefficient are calculated for a rotor operating in yawed conditions. In a first step, the power coefficient is determined using a model based on the blade element momentum theory (BEMT) which includes a Prandtl-Glauert root-tip losses correction, a non-uniform model for the axial and tangential induction factors, and a model of the rotational augmentation effects. The BEMT model is validated with the experimental data from the NREL-UAE. The maximum values of the power coefficient are determined for different yaw angles and the corresponding values of the tip speed ratio and blade control angle are obtained. The maximum power coefficient using these optimum laws is compared to the maximum power coefficient using the optimum laws of the non-yawed case and it is shown that there is a gain in the power coefficient. For the case study presented in this paper it has been found that for yaw angles of 30° about 10% of the power coefficient can be recovered.

Kalman Filtering and Smoothing of the Van Allen Probes Observations to Estimate the Radial, Energy and Pitch Angle Diffusion Rates

Science.gov (United States)

Podladchikova, T.; Shprits, Y.; Kellerman, A. C.

2015-12-01

The Kalman filter technique combines the strengths of new physical models of the Earth's radiation belts with long-term spacecraft observations of electron fluxes and therefore provide an extremely useful method for the analysis of the state and evolution of the electron radiation belts. However, to get the reliable data assimilation output, the Kalman filter application is confronted with a set of fundamental problems. E.g., satellite measurements are usually limited to a single location in space, which confines the reconstruction of the global evolution of the radiation environment. The uncertainties arise from the imperfect description of the process dynamics and the presence of observation errors, which may cause the failure of data assimilation solution. The development of adaptive Kalman filter that combines the Van Allen Probes data and 3-D VERB code, its accurate customizations in the reconstruction of model describing the phase space density (PSD) evolution, extension of the possibilities to use measurement information, and the model adjustment by developing the identification techniques of model and measurement errors allowed us to reveal hidden and implicit regularities of the PSD dynamics and obtain quantitative and qualitative estimates of radial, energy and pitch angle diffusion characteristics from satellite observations. In this study we propose an approach to estimate radial, energy and pitch angle diffusion rates, as well as the direction of their propagation.

Low Wind Speed Turbine Project Conceptual Design Study: Advanced Independent Pitch Control; July 30, 2002--July 31, 2004 (Revised)

Energy Technology Data Exchange (ETDEWEB)

Olsen, T.; Lang, E.; Hansen, A.C.; Cheney, M. C.; Quandt, G.; VandenBosche, J.; Meyer, T.

2004-12-01

AES conducted a conceptual study of independent pitch control using inflow angle sensors. The control strategy combined input from turbine states (rotor speed, rotor azimuth, each blade pitch) with inflow angle measurements (each blade angle of attack at station 11 of 15) to derive blade pitch demand signals. The controller reduced loads sufficiently to allow a 10% rotor extension and reduce COE by 6.3%.

Unsteady aerodynamics of a pitching-flapping-perturbed revolving wing at low Reynolds number

Science.gov (United States)

Chen, Long; Wu, Jianghao; Zhou, Chao; Hsu, Shih-Jung; Cheng, Bo

2018-05-01

Due to adverse viscous effects, revolving wings suffer universally from low efficiency at low Reynolds number (Re). By reciprocating wing revolving motion, natural flyers flying at low Re successfully exploit unsteady effects to augment force production and efficiency. Here we investigate the aerodynamics of an alternative, i.e., a revolving wing with concomitant unsteady pitching and vertical flapping perturbations (a pitching-flapping-perturbed revolving wing). The current work builds upon a previous study on flapping-perturbed revolving wings (FP-RWs) and focuses on combined effects of pitching-flapping perturbation on force generation and vortex behaviors. The results show that, compared with a FR-RW, pitching motion further (1) reduces the external driving torque for rotating at 0° angle of attack (α0) and (2) enhances lift and leads to a self-rotating equilibrium at α0 = 20°. The power loading of a revolving wing at α0 = 20° can be improved using pitching-flapping perturbations with large pitching amplitude but small Strouhal number. Additionally, an advanced pitching improves the reduction of external driving torque, whereas a delayed pitching weakens both the lift enhancement and the reduction of external driving torque. Further analysis shows that pitching effects can be mainly decomposed into the Leading-Edge-Vortex (LEV)-mediated pressure component and geometric projection component, together they determine the force performance. LEV circulation is found to be determined by the instantaneous effective angle of attack but could be affected asymmetrically between upstroke and downstroke depending on the nominal angle of attack. Pitching-flapping perturbation thus can potentially inspire novel mechanisms to improve the aerodynamic performance of rotary wing micro air vehicles.

High Pressure Angle Gears: Comparison to Typical Gear Designs

Science.gov (United States)

Handschuh, Robert F.; Zabrajsek, Andrew J.

2010-01-01

A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

Accurate approximation of in-ecliptic trajectories for E-sail with constant pitch angle

Science.gov (United States)

Huo, Mingying; Mengali, Giovanni; Quarta, Alessandro A.

2018-05-01

Propellantless continuous-thrust propulsion systems, such as electric solar wind sails, may be successfully used for new space missions, especially those requiring high-energy orbit transfers. When the mass-to-thrust ratio is sufficiently large, the spacecraft trajectory is characterized by long flight times with a number of revolutions around the Sun. The corresponding mission analysis, especially when addressed within an optimal context, requires a significant amount of simulation effort. Analytical trajectories are therefore useful aids in a preliminary phase of mission design, even though exact solution are very difficult to obtain. The aim of this paper is to present an accurate, analytical, approximation of the spacecraft trajectory generated by an electric solar wind sail with a constant pitch angle, using the latest mathematical model of the thrust vector. Assuming a heliocentric circular parking orbit and a two-dimensional scenario, the simulation results show that the proposed equations are able to accurately describe the actual spacecraft trajectory for a long time interval when the propulsive acceleration magnitude is sufficiently small.

Parametric study on off-design aerodynamic performance of a horizontal axis wind turbine blade and proposed pitch control

International Nuclear Information System (INIS)

Najafian Ashrafi, Z.; Ghaderi, M.; Sedaghat, A.

2015-01-01

Highlights: • A pitch controlled 200 kW HAWT blade is designed with BEM for off-design conditions. • Parametric study conducted on power coefficient, axial and angular induction factors. • The optimal pitch angles were determined at off-design operating conditions. - Abstract: In this paper, a 200 kW horizontal axis wind turbine (HAWT) blade is designed using an efficient iterative algorithm based on the blade element momentum theory (BEM) on aerodynamic of wind turbines. The effects of off-design variations of wind speed are investigated on the blade performance parameters according to constant rotational speed of the rotor. The performance parameters considered are power coefficient, axial and angular induction factors, lift and drag coefficients on the blade, angle of attack and angle of relative wind. At higher or lower wind speeds than the designed rated speed, the power coefficient is reduced due to considerable changes in the angle of attacks. Therefore, proper pitch control angles were calculated to extract maximum possible power at various off-design speeds. The results showed a considerable improvement in power coefficient for the pitch controlled blade as compared with the baseline design in whole operating range. The present approach can be equally employed for determining pitch angles to design pitch control system of medium and large-scale wind turbines

Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults

International Nuclear Information System (INIS)

Etemaddar, Mahmoud; Gao, Zhen; Moan, Torgeir

2014-01-01

In this paper, we investigate the characteristics of a wind turbine under blade pitch angle and shaft speed sensor faults as well as pitch actuator faults. A land-based NREL 5MW variable speed pitch reg- ulated wind turbine is considered as a reference. The conventional collective blade pitch angle controller strategy with independent pitch actuators control is used for load reduction. The wind turbine class is IEC-BII. The main purpose is to investigate the severity of end effects on structural loads and responses and consequently identify the high-risk components according to the type and amplitude of fault using a servo-aero-elastic simulation code, HAWC2. Both transient and steady state effects of faults are studied. Such information is useful for wind turbine fault detection and identification as well as system reliability analysis. Results show the effects of faults on wind turbine power output and responses. Pitch sensor faults mainly affects the vibration of shaft main bearing, while generator power and aerodynamic thrust are not changed significantly, due to independent pitch actuator control of three blades. Shaft speed sensor faults can seriously affect the generator power and aerodynamic thrust. Pitch actuator faults can result in fully pitching of the blade, and consequently rotor stops due to negative aerodynamic torque

Servo-Elastic Dynamics of a Hydraulic Actuator Pitching a Blade with Large Deflections

International Nuclear Information System (INIS)

Hansen, M H; Kallesoee, B S

2007-01-01

This paper deals with the servo-elastic dynamics of a hydraulic pitch actuator acting on a largely bend wind turbine blade. The compressibility of the oil and flexibility of the hoses introduce a dynamic mode in the pitch bearing degree of freedom. This mode may obtain negative damping if the proportional gain on the actuator position error is defined too large relative to the viscous forces in the hydraulic system and the total rotational inertia of the pitch bearing degree of freedom. A simple expression for the stability limit of this proportional gain is derived for tuning the gain based on the Ziegler-Nichols method. Computed transfer functions from reference to actual pitch angles indicate that the actuator can be approximated as a low-pass filter with some appropriate limitations on pitching speed and acceleration. The structural blade model includes the geometrical coupling of edgewise bending and torsion for large flapwise deflections. This coupling is shown to introduce edgewise bending response for pitch reference oscillations around the natural frequency of the edgewise bending mode, in which frequency range the transfer function from reference to actual pitch angle cannot be modeled as a simple low-pass filter. The pitch bearing is assumed to be frictionless as a first approximation

Numerical methods and transition investigation of transient flows around a pitching hydrofoil

International Nuclear Information System (INIS)

Wu, Q; Wang, G Y; Huang, B

2013-01-01

The numerical simulations for a NACA66 hydrofoil are performed by using the standard k-ω SST turbulence model and revised γ-Re θ transition model respectively. The simulation results are compared with the experimental results, and the hydrodynamic property and the fluid structure during the pitching process is studied. It is revealed that, compared with the standard k-ω SST turbulence model, the revised γ-Re θ transition model is able to present the hydrodynamic property and the fluid structure of the transient flow around a pitching hydrofoil more accurately, and better predict the separation and transition process in the boundary layer. The transient flow process around a pitching hydrofoil can be divided into 5 parts. At small angle of attack, transition is observed at the leading edge of the foil, resulting in the inflection of dynamic property curves. As the angle of attack increases, a clockwise trailing edge vortex expands toward the leading edge of the foil. At high angles of attack, large-scale load fluctuations are observed due to the stall caused by separation of the leading edge vortex. The flow transitions back to laminar during the downward pitching process

Wing-pitching mechanism of hovering Ruby-throated hummingbirds

International Nuclear Information System (INIS)

Song, Jialei; Luo, Haoxiang; Hedrick, Tyson L

2015-01-01

In hovering flight, hummingbirds reverse the angle of attack of their wings through pitch reversal in order to generate aerodynamic lift during both downstroke and upstroke. In addition, the wings may pitch during translation to further enhance lift production. It is not yet clear whether these pitching motions are caused by the wing inertia or actuated through the musculoskeletal system. Here we perform a computational analysis of the pitching dynamics by incorporating the realistic wing kinematics to determine the inertial effects. The aerodynamic effect is also included using the pressure data from a previous three-dimensional computational fluid dynamics simulation of a hovering hummingbird. The results show that like many insects, pitch reversal of the hummingbird is, to a large degree, caused by the wing inertia. However, actuation power input at the root is needed in the beginning of pronation to initiate a fast pitch reversal and also in mid-downstroke to enable a nose-up pitching motion for lift enhancement. The muscles on the wing may not necessarily be activated for pitching of the distal section. Finally, power analysis of the flapping motion shows that there is no requirement for substantial elastic energy storage or energy absorption at the shoulder joint. (paper)

Wing-pitching mechanism of hovering Ruby-throated hummingbirds.

Science.gov (United States)

Song, Jialei; Luo, Haoxiang; Hedrick, Tyson L

2015-01-19

In hovering flight, hummingbirds reverse the angle of attack of their wings through pitch reversal in order to generate aerodynamic lift during both downstroke and upstroke. In addition, the wings may pitch during translation to further enhance lift production. It is not yet clear whether these pitching motions are caused by the wing inertia or actuated through the musculoskeletal system. Here we perform a computational analysis of the pitching dynamics by incorporating the realistic wing kinematics to determine the inertial effects. The aerodynamic effect is also included using the pressure data from a previous three-dimensional computational fluid dynamics simulation of a hovering hummingbird. The results show that like many insects, pitch reversal of the hummingbird is, to a large degree, caused by the wing inertia. However, actuation power input at the root is needed in the beginning of pronation to initiate a fast pitch reversal and also in mid-downstroke to enable a nose-up pitching motion for lift enhancement. The muscles on the wing may not necessarily be activated for pitching of the distal section. Finally, power analysis of the flapping motion shows that there is no requirement for substantial elastic energy storage or energy absorption at the shoulder joint.

Measurement of internal magnetic field pitch using Li pellet injection on TFTR (invited)

International Nuclear Information System (INIS)

Terry, J.L.; Marmar, E.S.; Howell, R.B.; Bell, M.; Cavallo, A.; Fredrickson, E.; Ramsey, A.; Schmidt, G.L.; Stratton, B.; Taylor, G.; Mauel, M.E.

1990-01-01

A diagnostic technique which measures the direction of the internal magnetic field pitch angle has been used successfully on TFTR. The technique requires the injection of high-speed Li pellets. The magnetic field direction is measured by observing the polarization direction of the intense visible line emission from Li + (λ∼5485 A, 1s2p 3 P 0,1,2 →1s2s 3 S 0 ) in the pellet ablation cloud. The presence of the large (primarily toroidal) magnetic field causes the line to be split due to the Zeeman effect, and the unshifted π component is polarized with its polarization direction parallel to the local magnetic field. In devices with sufficiently strong fields (B approx-gt 4.5 T), the Zeeman splitting of the line is large enough, relative to the linewidth of each Zeeman component, that enough residual polarization remains. Because the pellet moves about 1 cm before the Li + is ionized (τ ionization approx-lt 10 μs), the time history of the polarization direction (as the pellet penetrates from the outside toward the plasma center) yields the local magnetic field direction. In the TFTR experiment, spatial resolution of the measurement is typically ∼7 cm, limited by the requirement that a large number of photons must be collected in order to make the measurement of the polarization angle. Typically, the pitch of the field is measured with an accuracy of ±0.01 rad, limited by the photon statistics. The measurements of the internal field pitch angle, combined with external magnetic measurements, have been used in a code which finds the solution of the Grad--Shafranov equation, yielding the equilibrium which is the best fit to the measured inputs

Anisotropic distribution function of minority tail ions generated by strong ion-cyclotron resonance heating

International Nuclear Information System (INIS)

Chang, C.S.; Colestock, P.

1989-05-01

The highly anisotropic particle distribution function of minority tail ions driven by ion-cyclotron resonance heating at the fundamental harmonic is calculated in a two-dimensional velocity space. It is assumed that the heating is strong enough to drive most of the resonant ions above the in-electron critical slowing-down energy. Simple analytic expressions for the tail distribution are obtained fro the case when the Doppler effect is sufficiently large to flatten the sharp pitch angle dependence in the bounce averaged qualilinear heating coefficient, D/sub b/, and for the case when D/sub b/ is assumed to be constant in pitch angle and energy. It is found that a simple constant-D/sub b/ solution can be used instead of the more complicated sharp-D/sub b/ solution for many analytic purposes. 4 refs., 4 figs

Characteristics of Pitch Angle Distributions of 100s Kev Electrons in the Slot Region and Inner Radiation Belt­­­­­­­­

Science.gov (United States)

Zhao, H.; Li, X.; Blake, J. B.; Fennell, J.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D.

2014-12-01

The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-art pitch-angle-resolved data from the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes, a detailed analysis of 100s keV electron PADs below L =4 is performed, in which the PADs is categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°) and 90°-minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of 460 keV electrons for over a year, we find that the 90°-minimum PADs are generally present in the inner belt (Lpitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L=3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2mechanism can hardly explain the formation of 90°-minimum PADs at the center of inner belt. These new and compelling observations, made possible by the high-quality measurements of MagEIS, present a challenge for the wave modelers, and future work is still needed to fully understand them.

The Effects of Inlet Box Aerodynamics on the Mechanical Performance of a Variable Pitch in Motion Fan

OpenAIRE

Sheard, A. G.

2012-01-01

This paper describes research involving an in-service failure of a “variable pitch in motion” fan’s blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addre...

Performance of a 3 kW wind turbine generator with variable pitch control system

International Nuclear Information System (INIS)

Nagai, Baku M.; Ameku, Kazumasa; Roy, Jitendro Nath

2009-01-01

A prototype 3 kW horizontal upwind type wind turbine generator of 4 m in diameter has been designed and examined under real wind conditions. The machine was designed based on the concept that even small wind turbines should have a variable pitch control system just as large wind turbines, especially in Japan where typhoons occur at least once a year. A characteristic of the machine is the use of a worm and gear system with a stepping motor installed in the center of the hub, and the rotational main shaft. The machine is constructed with no mechanical breaking system so as to avoid damage from strong winds. In a storm, the wind turbine is slowed down by adjusting the pitch angle and the maximum electrical load. Usually the machine is controlled at several stages depending on the rotational speed of the blades. Two control methods have been applied: the variable pitch angle, and regulation of the generator field current. The characteristics of the generator under each rotational speed and field current are first investigated in the laboratory. This paper describes the performances of the wind turbine in terms of the functions of wind turbine rotational speed, generated outputs, and its stability for wind speed changes. The expected performances of the machine have been confirmed under real wind conditions and compared with numerical simulation results. The wind turbine showed a power coefficient of 0.257 under the average wind speed of 7.3 m/s.

Active Blade Pitch Control for Straight Bladed Darrieus Vertical Axis Wind Turbine of New Design

DEFF Research Database (Denmark)

Chougule, Prasad; Nielsen, Søren R.K.; Basu, Biswajit

2013-01-01

in a previous publication. Further, it is well know that the variation of the blade pitch angle during the rotation improves the power efficiency. A blade pitch variation is implemented by active blade pitch control, which operates as per wind speed and position of the blade with respect to the rotor. A double...

Influence of pitch, twist, and taper on a blade`s performance loss due to roughness

Energy Technology Data Exchange (ETDEWEB)

Tangler, J.L. [National Renewable Energy Lab., Golden, CO (United States)

1996-12-31

The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade`s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor`s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP computer code with wind-tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord, non-twisted blade at several blade pitch angles. The results indicate that a constant-chord, non-twisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. 8 refs., 6 figs.

Influence of pitch, twist, and taper on a blade`s performance loss due to roughness

Energy Technology Data Exchange (ETDEWEB)

Tangler, J.L. [National Renewable Energy Laboratory, Golden, Colorado (United States)

1997-08-01

The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade`s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor`s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP computer code with wind-tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord, non-twisted blade at several blade pitch angles. The results indicate that a constant-chord, non-twisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. (au)

Pitch Angle Dependence of Drift Resonant Ions Observed by the Van Allen Probes

Science.gov (United States)

Rankin, R.; Wang, C.; Wang, Y.; Zong, Q. G.; Zhou, X.

2017-12-01

Acceleration and modulation of ring current ions by poloidal mode ULF waves is investigated. A simplified MHD model of ULF waves in a dipole magnetic field is presented that includes phase mixing to perpendicular scales determined by the ionospheric Pedersen conductivity. The wave model is combined with a full Lorentz force test particle code to study drift and drift bounce resonance wave-particle interactions. Ion trajectories are traced backward-in-time to an assumed form of the distribution function, and Liouville's method is used to reconstruct the phase space density response (PSD) poloidal mode waves observed by the Van Allen Probes. In spite of its apparent simplicity, simulations using the wave and test particle models are able to explain the acceleration of ions and energy dispersion observed by the Van Allen Probes. The paper focuses on the pitch angle evolution of the initial PSD as it responds to the action of ULF waves. An interesting aspect of the study is the formation of butterfly ion distributions as ions make periodic radial oscillations across L. Ions become trapped in an effective potential well across a limited range of L and follow trajectories that cause them to surf along constant phase fronts. The impications of this new trapping mechanism for both ions and electrons is discussed.

Effects of grit roughness and pitch oscillations on the S809 airfoil

Energy Technology Data Exchange (ETDEWEB)

Ramsay, R.F.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1995-12-01

An S809 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3{times}5 subsonic wind tunnel (3{times}5) under steady flow and stationary model conditions, and also with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was developed to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, 1.25, and 1.5 million, while the angle of attack ranged from {minus}20, to +40 {degrees}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {plus_minus} 5.5{degrees} and {plus_minus} 10{degrees}, at mean angles of attack of 8{degrees}, 14{degrees}, and 20{degrees}. For purposes herein, any reference to unsteady conditions means the model was in pitch oscillation about the quarter chord. In general, the unsteady maximum lift coefficient was from 4% to 86% higher than the steady state maximum lift coefficient, and variation in the quarter chord pitching moment coefficient magnitude was from {minus}83% to 195% relative to steady state values at high angles of attack. These findings indicate the importance of considering the unsteady flow behavior occurring in wind turbine operation to obtain accurate load estimates.

Variable Pitch Darrieus Water Turbines

Science.gov (United States)

Kirke, Brian; Lazauskas, Leo

In recent years the Darrieus wind turbine concept has been adapted for use in water, either as a hydrokinetic turbine converting the kinetic energy of a moving fluid in open flow like an underwater wind turbine, or in a low head or ducted arrangement where flow is confined, streamtube expansion is controlled and efficiency is not subject to the Betz limit. Conventional fixed pitch Darrieus turbines suffer from two drawbacks, (i) low starting torque and (ii) shaking due to cyclical variations in blade angle of attack. Ventilation and cavitation can also cause problems in water turbines when blade velocities are high. Shaking can be largely overcome by the use of helical blades, but these do not produce large starting torque. Variable pitch can produce high starting torque and high efficiency, and by suitable choice of pitch regime, shaking can be minimized but not entirely eliminated. Ventilation can be prevented by avoiding operation close to a free surface, and cavitation can be prevented by limiting blade velocities. This paper summarizes recent developments in Darrieus water turbines, some problems and some possible solutions.

A New Method to Calibrate Attachment Angles of Data Loggers in Swimming Sharks

Directory of Open Access Journals (Sweden)

Shizuka Kawatsu

2010-01-01

Full Text Available Recently, animal-borne accelerometers have been used to record the pitch angle of aquatic animals during swimming. When evaluating pitch angle, it is necessary to consider a discrepancy between the angle of an accelerometer and the long axis of an animal. In this study, we attached accelerometers to 17 free-ranging scalloped hammerhead shark (Sphyrna lewini pups from Kaneohe Bay, Hawaii. Although there are methods to calibrate attachment angles of accelerometers, we confirmed that previous methods were not applicable for hammerhead pups. According to raw data, some sharks ascended with a negative angle, which differs from tank observations of captive sharks. In turn, we developed a new method to account for this discrepancy in swimming sharks by estimating the attachment angle from the relationship between vertical speed (m/s and pitch angle obtained by each accelerometer. The new method can be utilized for field observation of a wide range of species.

Forced pitch motion of wind turbines

Science.gov (United States)

Leble, V.; Barakos, G.

2016-09-01

The possibility of a wind turbine entering vortex ring state during pitching oscillations is explored in this paper. The aerodynamic performance of the rotor was computed using the Helicopter Multi-Block flow solver. This code solves the Navier-Stokes equations in integral form using the arbitrary Lagrangian-Eulerian formulation for time-dependent domains with moving boundaries. A 10-MW wind turbine was put to perform yawing and pitching oscillations suggesting the partial vortex ring state during pitching motion. The results also show the strong effect of the frequency and amplitude of oscillations on the wind turbine performance.

Forced pitch motion of wind turbines

International Nuclear Information System (INIS)

Leble, V; Barakos, G

2016-01-01

The possibility of a wind turbine entering vortex ring state during pitching oscillations is explored in this paper. The aerodynamic performance of the rotor was computed using the Helicopter Multi-Block flow solver. This code solves the Navier-Stokes equations in integral form using the arbitrary Lagrangian-Eulerian formulation for time-dependent domains with moving boundaries. A 10-MW wind turbine was put to perform yawing and pitching oscillations suggesting the partial vortex ring state during pitching motion. The results also show the strong effect of the frequency and amplitude of oscillations on the wind turbine performance. (paper)

A Neural Network Approach for Identifying Particle Pitch Angle Distributions in Van Allen Probes Data

Science.gov (United States)

Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.;

Design of LPV fault-tolerant controller for pitch system of wind turbine

Science.gov (United States)

Wu, Dinghui; Zhang, Xiaolin

2017-07-01

To address failures of wind turbine pitch-angle sensors, traditional wind turbine linear parameter varying (LPV) model is transformed into a double-layer convex polyhedron LPV model. On the basis of this model, when the plurality of the sensor undergoes failure and details of the failure are inconvenient to obtain, each sub-controller is designed using distributed thought and gain scheduling method. The final controller is obtained using all of the sub-controllers by a convex combination. The design method corrects the errors of the linear model, improves the linear degree of the system, and solves the problem of multiple pitch angle faults to ensure stable operation of the wind turbine.

The deflection angle of a gravitational source with a global monopole in the strong field limit

International Nuclear Information System (INIS)

Cheng Hongbo; Man Jingyun

2011-01-01

We investigate the gravitational lensing effect in the strong field background around the Schwarzschild black hole with extremely small mass and solid deficit angle subject to the global monopole by means of the strong field limit issue. We obtain the angular position and magnification of the relativistic images and show that they relate to the global monopole parameter η. We discuss that with the increase of the parameter η, the minimum impact parameter u m and angular separation s increase and the relative magnification r decreases. We also find that s grows extremely as the increasing parameter η becomes large enough. The deflection angle will become larger when the parameter η grows. The effect from the solid deficit angle is the dependence of angular position, angular separation, relative magnification and deflection angle on the parameter η, which may offer a way to characterize some possible distinct signatures of the Schwarzschild black hole with a solid deficit angle associated with the global monopole.

Pointed and plateau-shaped pitch accents in North Frisian

DEFF Research Database (Denmark)

Niebuhr, Oliver; Hoekstra, Jarich

2015-01-01

for language documentation and conservation purposes. We selected a small part of this corpus – interviews of 10 elderly speakers – and conducted multiparametric F0 and duration measurements, focusing on nuclear rising-falling pitch accent patterns. We found strong evidence for a phonological pitch...

Pitch angle distribution of trapped energetic protons and helium isotope nuclei measured along the Resurs-01 No. 4 LEO satellite

Directory of Open Access Journals (Sweden)

A. Leonov

2005-11-01

Full Text Available The NINA detector on board the Resurs-01 No. 4 satellite (835 km, 98° inclination is equipped with particle trackers based on silicon strip detectors. From the energy deposited in each of its silicon layers the mass, the momentum direction and energy of incident particles have been determined. The resolutions in mass and energy allow identification of H and He isotopes over the 10-50 MeV/n energy range. The angular resolution is about 2.5°. We present the direct measurements of proton and helium isotopes pitch angle distributions derived from Resurs-01 No.4/NINA observations and their variations as functions of (B, L coordinates and energy. The measurements of trapped helium isotopes spectrum are also presented.

Effects of grit roughness and pitch oscillations on the LS(1)-0421MOD airfoil

Energy Technology Data Exchange (ETDEWEB)

Reuss, R.L.; HOffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1995-12-01

An LS(1)-0421 MOD airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3{times}5 subsonic wind tunnel (3{times}5) under steady flow and stationary model conditions, and also with the model undergoing pitch oscillations. In order to study the possible extent of performance loss due to surface roughness, a leading edge grit roughness (LEGR) pattern was developed to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, and 1.25 million, while the angle of attack ranged from {minus}10{degrees} to +40{degrees}. With the model undergoing pitch oscillations, data was acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.5 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {plus_minus} 5.5{degrees} and {plus_minus} 10{degrees}, at mean angles of attack of 8{degrees}, 14{degrees}, and 20{degrees}. For this report, unsteady conditions refer to the model in pitch oscillation. In general, the maximum unsteady lift coefficient was from 10% to 50% higher than the steady state maximum lift coefficient. Variation in the quarter chord pitching moment coefficient was nearly two times greater than steady state values at high angles of attack. These findings indicate the importance of considering the unsteady flow behavior occurring in wind turbine operation for accurate load estimates.

Vowel identity between note labels confuses pitch identification in non-absolute pitch possessors.

Directory of Open Access Journals (Sweden)

Alfredo Brancucci

Full Text Available The simplest and likeliest assumption concerning the cognitive bases of absolute pitch (AP is that at its origin there is a particularly skilled function which matches the height of the perceived pitch to the verbal label of the musical tone. Since there is no difference in sound frequency resolution between AP and non-AP (NAP musicians, the hypothesis of the present study is that the failure of NAP musicians in pitch identification relies mainly in an inability to retrieve the correct verbal label to be assigned to the perceived musical note. The primary hypothesis is that, when asked to identify tones, NAP musicians confuse the verbal labels to be attached to the stimulus on the basis of their phonetic content. Data from two AP tests are reported, in which subjects had to respond in the presence or in the absence of visually presented verbal note labels (fixed Do solmization. Results show that NAP musicians confuse more frequently notes having a similar vowel in the note label. They tend to confuse e.g. a 261 Hz tone (Do more often with Sol than, e.g., with La. As a second goal, we wondered whether this effect is lateralized, i.e. whether one hemisphere is more responsible than the other in the confusion of notes with similar labels. This question was addressed by observing pitch identification during dichotic listening. Results showed that there is a right hemispheric disadvantage, in NAP but not AP musicians, in the retrieval of the verbal label to be assigned to the perceived pitch. The present results indicate that absolute pitch has strong verbal bases, at least from a cognitive point of view.

A Novel Degradation Identification Method for Wind Turbine Pitch System

Science.gov (United States)

Guo, Hui-Dong

2018-04-01

It’s difficult for traditional threshold value method to identify degradation of operating equipment accurately. An novel degradation evaluation method suitable for wind turbine condition maintenance strategy implementation was proposed in this paper. Based on the analysis of typical variable-speed pitch-to-feather control principle and monitoring parameters for pitch system, a multi input multi output (MIMO) regression model was applied to pitch system, where wind speed, power generation regarding as input parameters, wheel rotation speed, pitch angle and motor driving currency for three blades as output parameters. Then, the difference between the on-line measurement and the calculated value from the MIMO regression model applying least square support vector machines (LSSVM) method was defined as the Observed Vector of the system. The Gaussian mixture model (GMM) was applied to fitting the distribution of the multi dimension Observed Vectors. Applying the model established, the Degradation Index was calculated using the SCADA data of a wind turbine damaged its pitch bearing retainer and rolling body, which illustrated the feasibility of the provided method.

Control design for a pitch-regulated, variable speed wind turbine

DEFF Research Database (Denmark)

Hansen, M.H.; Hansen, Anca Daniela; Larsen, Torben J.

2005-01-01

The three different controller designs presented herein are similar and all based on PI-regulation of rotor speed and power through the collective blade pitch angle and generator moment. The aeroelastic and electrical modelling used for the time-domainanalysis of these controllers are however...... different, which makes a directly quantitative comparison difficult. But there are some observations of similar behaviours should be mentioned: • Very similar step responses in rotor speed, pitch angle, and powerare seen for simulations with steps in wind speed. • All controllers show a peak in power...... for wind speed step-up over rated wind speed, which can be almost removed by changing the parameters of the frequency converter. • Responses of rotor speed, pitchangle, and power for different simulations with turbulent inflow are similar for all three controllers. Again, there seems to be an advantage...

Facial Expression and Vocal Pitch Height: Evidence of an Intermodal Association

Directory of Open Access Journals (Sweden)

David Huron

2009-11-01

Full Text Available Forty-four participants were asked to sing moderate, high, and low pitches while their faces were photographed. In a two-alternative forced choice task, independent judges selected the high-pitch faces as more friendly than the low-pitch faces. When photographs were cropped to show only the eye region, judges still rated the high-pitch faces friendlier than the low-pitch faces. These results are consistent with prior research showing that vocal pitch height is used to signal aggression (low pitch or appeasement (high pitch. An analysis of the facial features shows a strong correlation between eyebrow position and sung pitch—consistent with the role of eyebrows in signaling aggression and appeasement. Overall, the results are consistent with an inter-modal linkage between vocal and facial expressions.

In search of rules behind environmental framing; the case of head pitch.

Science.gov (United States)

Wilson, Gwendoline Ixia; Norman, Brad; Walker, James; Williams, Hannah J; Holton, M D; Clarke, D; Wilson, Rory P

2015-01-01

Whether, and how, animals move requires them to assess their environment to determine the most appropriate action and trajectory, although the precise way the environment is scanned has been little studied. We hypothesized that head attitude, which effectively frames the environment for the eyes, and the way it changes over time, would be modulated by the environment. To test this, we used a head-mounted device (Human-Interfaced Personal Observation platform - HIPOP) on people moving through three different environments; a botanical garden ('green' space), a reef ('blue' space), and a featureless corridor, to examine if head movement in the vertical axis differed between environments. Template matching was used to identify and quantify distinct behaviours. The data on head pitch from all subjects and environments over time showed essentially continuous clear waveforms with varying amplitude and wavelength. There were three stylised behaviours consisting of smooth, regular peaks and troughs in head pitch angle and variable length fixations during which the head pitch remained constant. These three behaviours accounted for ca. 40 % of the total time, with irregular head pitch changes accounting for the rest. There were differences in rates of manifestation of behaviour according to environment as well as environmentally different head pitch values of peaks, troughs and fixations. Finally, although there was considerable variation in head pitch angles, the peak and trough values bounded most of the variation in the fixation pitch values. It is suggested that the constant waveforms in head pitch serve to inform people about their environment, providing a scanning mechanism. Particular emphasis to certain sectors is manifest within the peak and trough limits and these appear modulated by the distribution of the points where fixation, interpreted as being due to objects of interest, occurs. This behaviour explains how animals allocate processing resources to the

Vortex scale of unsteady separation on a pitching airfoil.

Science.gov (United States)

Fuchiwaki, Masaki; Tanaka, Kazuhiro

2002-10-01

The streaklines of unsteady separation on two kinds of pitching airfoils, the NACA65-0910 and a blunt trailing edge airfoil, were studied by dye flow visualization and by the Schlieren method. The latter visualized the discrete vortices shed from the leading edge. The results of these visualization studies allow a comparison between the dynamic behavior of the streakline of unsteady separation and that of the discrete vortices shed from the leading edge. The influence of the airfoil configuration on the flow characteristics was also examined. Furthermore, the scale of a discrete vortex forming the recirculation region was investigated. The non-dimensional pitching rate was k = 0.377, the angle of attack alpha(m) = 16 degrees and the pitching amplitude was fixed to A = +/-6 degrees for Re = 4.0 x 10(3) in this experiment.

Supersonic flow over a pitching delta wing using surface pressure measurements and numerical simulations

Directory of Open Access Journals (Sweden)

Mostafa HADIDOOLABI

2018-01-01

Full Text Available Experimental and numerical methods were applied to investigating high subsonic and supersonic flows over a 60° swept delta wing in fixed state and pitching oscillation. Static pressure coefficient distributions over the wing leeward surface and the hysteresis loops of pressure coefficient versus angle of attack at the sensor locations were obtained by wind tunnel tests. Similar results were obtained by numerical simulations which agreed well with the experiments. Flow structure around the wing was also demonstrated by the numerical simulation. Effects of Mach number and angle of attack on pressure distribution curves in static tests were investigated. Effects of various oscillation parameters including Mach number, mean angle of attack, pitching amplitude and frequency on hysteresis loops were investigated in dynamic tests and the associated physical mechanisms were discussed. Vortex breakdown phenomenon over the wing was identified at high angles of attack using the pressure coefficient curves and hysteresis loops, and its effects on the flow features were discussed.

Pitch-angle diffusion of electrons through growing and propagating along a magnetic field electromagnetic wave in Earth's radiation belts

International Nuclear Information System (INIS)

Choi, C.-R.; Dokgo, K.; Min, K.-W.; Woo, M.-H.; Choi, E.-J.; Hwang, J.; Park, Y.-D.; Lee, D.-Y.

2015-01-01

The diffusion of electrons via a linearly polarized, growing electromagnetic (EM) wave propagating along a uniform magnetic field is investigated. The diffusion of electrons that interact with the growing EM wave is investigated through the autocorrelation function of the parallel electron acceleration in several tens of electron gyration timescales, which is a relatively short time compared with the bounce time of electrons between two mirror points in Earth's radiation belts. Furthermore, the pitch-angle diffusion coefficient is derived for the resonant and non-resonant electrons, and the effect of the wave growth on the electron diffusion is discussed. The results can be applied to other problems related to local acceleration or the heating of electrons in space plasmas, such as in the radiation belts

Biomimetic propulsion under random heaving conditions, using active pitch control

Science.gov (United States)

Politis, Gerasimos; Politis, Konstantinos

2014-05-01

Marine mammals travel long distances by utilizing and transforming wave energy to thrust through proper control of their caudal fin. On the other hand, manmade ships traveling in a wavy sea store large amounts of wave energy in the form of kinetic energy for heaving, pitching, rolling and other ship motions. A natural way to extract this energy and transform it to useful propulsive thrust is by using a biomimetic wing. The aim of this paper is to show how an actively pitched biomimetic wing could achieve this goal when it performs a random heaving motion. More specifically, we consider a biomimetic wing traveling with a given translational velocity in an infinitely extended fluid and performing a random heaving motion with a given energy spectrum which corresponds to a given sea state. A formula is invented by which the instantaneous pitch angle of the wing is determined using the heaving data of the current and past time steps. Simulations are then performed for a biomimetic wing at different heave energy spectra, using an indirect Source-Doublet 3-D-BEM, together with a time stepping algorithm capable to track the random motion of the wing. A nonlinear pressure type Kutta condition is applied at the trailing edge of the wing. With a mollifier-based filtering technique, the 3-D unsteady rollup pattern created by the random motion of the wing is calculated without any simplifying assumptions regarding its geometry. Calculated unsteady forces, moments and useful power, show that the proposed active pitch control always results in thrust producing motions, with significant propulsive power production and considerable beneficial stabilizing action to ship motions. Calculation of the power required to set the pitch angle prove it to be a very small percentage of the useful power and thus making the practical application of the device very tractable.

Effects of harmonic roving on pitch discrimination

DEFF Research Database (Denmark)

Santurette, Sébastien; de Kérangal, Mathilde le Gal; Joshi, Suyash Narendra

2015-01-01

Performance in pitch discrimination tasks is limited by variability intrinsic to listeners which may arise from peripheral auditory coding limitations or more central noise sources. The present study aimed at quantifying such “internal noise” by estimating the amount of harmonic roving required...... to impair pitch discrimination performance. Fundamental-frequency difference limens (F0DLs) were obtained in normal-hearing listeners with and without musical training for complex tones filtered between 1.5 and 3.5 kHz with F0s of 300 Hz (resolved harmonics) and 75 Hz (unresolved harmonics). The harmonicity...... that could be used to quantify the internal noise and provide strong constraints for physiologically inspired models of pitch perception....

On the evolution of jet energy and opening angle in strongly coupled plasma

International Nuclear Information System (INIS)

Chesler, Paul M.; Rajagopal, Krishna

2016-01-01

We calculate how the energy and the opening angle of jets in N=4 SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE_j_e_t/dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE_j_e_t/dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that N=4 SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the N=4 SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. We close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.

A Pilot Model for the NASA Simplified Aid for EVA Rescue (SAFER) (Single-Axis Pitch Task)

Science.gov (United States)

Handley, Patrick Mark

This thesis defines, tests, and validates a descriptive pilot model for a single-axis pitch control task of the Simplified Aid for EVA Rescue (SAFER). SAFER is a small propulsive jetpack used by astronauts for self-rescue. Pilot model research supports development of improved self-rescue strategies and technologies through insights into pilot behavior.This thesis defines a multi-loop pilot model. The innermost loop controls the hand controller, the middle loop controls pitch rate, and the outer loop controls pitch angle. A human-in-the-loop simulation was conducted to gather data from a human pilot. Quantitative and qualitative metrics both indicate that the model is an acceptable fit to the human data. Fuel consumption was nearly identical; time to task completion matched very well. There is some evidence that the model responds faster to initial pitch rates than the human, artificially decreasing the model's time to task completion. This pilot model is descriptive, not predictive, of the human pilot. Insights are made into pilot behavior from this research. Symmetry implies that the human responds to positive and negative initial conditions with the same strategy. The human pilot appears indifferent to pitch angles within 0.5 deg, coasts at a constant pitch rate 1.09 deg/s, and has a reaction delay of 0.1 s.

Aerodynamics power consumption for mechanical flapping wings undergoing flapping and pitching motion

Science.gov (United States)

Razak, N. A.; Dimitriadis, G.; Razaami, A. F.

2017-07-01

Lately, due to the growing interest in Micro Aerial Vehicles (MAV), interest in flapping flight has been rekindled. The reason lies in the improved performance of flapping wing flight at low Reynolds number regime. Many studies involving flapping wing flight focused on the generation of unsteady aerodynamic forces such as lift and thrust. There is one aspect of flapping wing flight that received less attention. The aspect is aerodynamic power consumption. Since most mechanical flapping wing aircraft ever designed are battery powered, power consumption is fundamental in improving flight endurance. This paper reports the results of experiments carried out on mechanical wings under going active root flapping and pitching in the wind tunnel. The objective of the work is to investigate the effect of the pitch angle oscillations and wing profile on the power consumption of flapping wings via generation of unsteady aerodynamic forces. The experiments were repeated for different airspeeds, flapping and pitching kinematics, geometric angle of attack and wing sections with symmetric and cambered airfoils. A specially designed mechanical flapper modelled on large migrating birds was used. It will be shown that, under pitch leading conditions, less power is required to overcome the unsteady aerodnamics forces. The study finds less power requirement for downstroke compared to upstroke motion. Overall results demonstrate power consumption depends directly on the unsteady lift force.

The Effect of Glancing Angle Deposition Conditions on the Morphology of a Silver Nanohelix Array

Directory of Open Access Journals (Sweden)

Yi-Jun Jen

2017-09-01

Full Text Available Silver nanohelices were grown on smooth substrates using glancing angle deposition and substrate cooling. Various nanohelix arrays were deposited under different deposition conditions—different deposition rates, substrate spin rates, deposition angles, and substrate temperatures. The effect of deposition conditions on the morphology of each nanohelix array in terms of pitch angle, pitch length, wire diameter, and radius of curvature was investigated. The dependence of circular dichroism on the size of the nanohelix arrays was also measured and demonstrated.

Development of advanced blade pitching kinematics for cycloturbines and cyclorotors

Science.gov (United States)

Adams, Zachary Howard

Cycloturbines and cyclorotors are established concepts for extracting freesteam fluid energy and producing thrust which promise to exceed the performance of traditional horizontal axis turbines and rotors while maintaining unique operational advantages. However, their potential is not yet realized in widespread applications. A central barrier to their proliferation is the lack of fundamental understanding of the aerodynamic interaction between the turbine and the freestream flow. In particular, blade pitch must be precisely actuated throughout the revolution to achieve the proper blade angle of attack and maximize performance. So far, there is no adequate method for determining or implementing the optimal blade pitching kinematics for cyclorotors or cycloturbines. This dissertation bridges the pitching deficiency by introducing a novel low order model to predict improved pitch kinematics, experimentally demonstrating improved performance, and evaluating flow physics with a high order Navier-Stokes computational code. The foundation for developing advanced blade pitch motions is a low order model named Fluxline Theory. Fluid calculations are performed in a coordinate system fixed to streamlines whose spatial locations are not pre-described in order to capture the flow expansion/contraction and bending through the turbine. A transformation then determines the spatial location of streamlines through the rotor disk and finally blade element method integrations determine the power and forces produced. Validation against three sets of extant cycloturbine experimental data demonstrates improvement over other existing streamtube models. Fluxline Theory was extended by removing dependence on a blade element model to better understand how turbine-fluid interaction impacts thrust and power production. This pure momentum variation establishes a cycloturbine performance limit similar to the Betz Limit for horizontal axis wind turbines, as well as the fluid deceleration required

Investigation on pitch system loads by means of an integral multi body simulation approach

Science.gov (United States)

Berroth, J.; Jacobs, G.; Kroll, T.; Schelenz, R.

2016-09-01

In modern horizontal axis wind turbines the rotor blades are adjusted by three individual pitch systems to control power output. The pitch system consists of either a hydraulic or an electrical actuator, the blade bearing, the rotor blade itself and the control. In case of an electrical drive a gearbox is used to transmit the high torques that are required for blade pitch angle adjustment. In this contribution a new integral multi body simulation approach is presented that enables detailed assessment of dynamic pitch system loads. The simulation results presented are compared and evaluated with measurement data of a 2 MW-class reference wind turbine. Major focus of this contribution is on the assessment of non linear tooth contact behaviour incorporating tooth backlash for the single gear stages and the impact on dynamic pitch system loads.

Exploring the Effects of Pitch Layout on Learning a New Musical Instrument

Directory of Open Access Journals (Sweden)

Jennifer MacRitchie

2017-11-01

Full Text Available Although isomorphic pitch layouts are proposed to afford various advantages for musicians playing new musical instruments, this paper details the first substantive set of empirical tests on how two fundamental aspects of isomorphic pitch layouts affect motor learning: shear, which makes the pitch axis vertical, and the adjacency (or nonadjacency of pitches a major second apart. After receiving audio-visual training tasks for a scale and arpeggios, performance accuracies of 24 experienced musicians were assessed in immediate retention tasks (same as the training tasks, but without the audio-visual guidance and in a transfer task (performance of a previously untrained nursery rhyme. Each participant performed the same tasks with three different pitch layouts and, in total, four different layouts were tested. Results show that, so long as the performance ceiling has not already been reached (due to ease of the task or repeated practice, adjacency strongly improves performance accuracy in the training and retention tasks. They also show that shearing the layout, to make the pitch axis vertical, worsens performance accuracy for the training tasks but, crucially, it strongly improves performance accuracy in the transfer task when the participant needs to perform a new, but related, task. These results can inform the design of pitch layouts in new musical instruments.

Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, M.J.; Reuss Ramsay, R.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-07-01

A NACA 4415 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from {minus}10{degree} to +40{degree} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, these were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Steady state results of the NACA 4415 testing at Reynolds number of 1.25 million showed a baseline maximum lift coefficient of 1.30 at 12.3{degree} angle of attack. The application of LEGR reduced the maximum lift coefficient by 20% and increased the 0.0090 minimum drag coefficient value by 62%. The zero lift pitching moment of {minus}0.0967 showed a 13% reduction in magnitude to {minus}0.0842 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {+-}5.5{degree} and {+-}10{degree}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude, and both unsteady maximum lift coefficients were greater than the steady state values. Stall is delayed on the airfoil while the angle of attack is increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack. In addition, with LEGR, the hysteresis behavior persisted into lower angles of attack than for the clean case.

Discrete Element Method Modeling of the Rheological Properties of Coke/Pitch Mixtures.

Science.gov (United States)

Majidi, Behzad; Taghavi, Seyed Mohammad; Fafard, Mario; Ziegler, Donald P; Alamdari, Houshang

2016-05-04

Rheological properties of pitch and pitch/coke mixtures at temperatures around 150 °C are of great interest for the carbon anode manufacturing process in the aluminum industry. In the present work, a cohesive viscoelastic contact model based on Burger's model is developed using the discrete element method (DEM) on the YADE, the open-source DEM software. A dynamic shear rheometer (DSR) is used to measure the viscoelastic properties of pitch at 150 °C. The experimental data obtained is then used to estimate the Burger's model parameters and calibrate the DEM model. The DSR tests were then simulated by a three-dimensional model. Very good agreement was observed between the experimental data and simulation results. Coke aggregates were modeled by overlapping spheres in the DEM model. Coke/pitch mixtures were numerically created by adding 5, 10, 20, and 30 percent of coke aggregates of the size range of 0.297-0.595 mm (-30 + 50 mesh) to pitch. Adding up to 30% of coke aggregates to pitch can increase its complex shear modulus at 60 Hz from 273 Pa to 1557 Pa. Results also showed that adding coke particles increases both storage and loss moduli, while it does not have a meaningful effect on the phase angle of pitch.

Experimental study of pitching and plunging airfoils at low Reynolds numbers

Energy Technology Data Exchange (ETDEWEB)

Baik, Yeon Sik; Bernal, Luis P. [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States)

2012-12-15

Measurements of the unsteady flow structure and force time history of pitching and plunging SD7003 and flat plate airfoils at low Reynolds numbers are presented. The airfoils were pitched and plunged in the effective angle of attack range of 2.4 -13.6 (shallow-stall kinematics) and -6 to 22 (deep-stall kinematics). The shallow-stall kinematics results for the SD7003 airfoil show attached flow and laminar-to-turbulent transition at low effective angle of attack during the down stroke motion, while the flat plate model exhibits leading edge separation. Strong Re-number effects were found for the SD7003 airfoil which produced approximately 25 % increase in the peak lift coefficient at Re = 10,000 compared to higher Re flows. The flat plate airfoil showed reduced Re effects due to leading edge separation at the sharper leading edge, and the measured peak lift coefficient was higher than that predicted by unsteady potential flow theory. The deep-stall kinematics resulted in leading edge separation that led to formation of a large leading edge vortex (LEV) and a small trailing edge vortex (TEV) for both airfoils. The measured peak lift coefficient was significantly higher ({proportional_to}50 %) than that for the shallow-stall kinematics. The effect of airfoil shape on lift force was greater than the Re effect. Turbulence statistics were measured as a function of phase using ensemble averages. The results show anisotropic turbulence for the LEV and isotropic turbulence for the TEV. Comparison of unsteady potential flow theory with the experimental data showed better agreement by using the quasi-steady approximation, or setting C(k) = 1 in Theodorsen theory, for leading edge-separated flows. (orig.)

Study of Pumping Capacity of Pitched Blade Impellers

Directory of Open Access Journals (Sweden)

I. Fořt

2002-01-01

Full Text Available A study was made of the pumping capacity of pitched blade impellers in a cylindrical pilot plant vessel with four standard radial baffles at the wall under a turbulent regime of flow. The pumping capacity was calculated from the radial profile of the axial flow, under the assumption of axial symmetry of the discharge flow. The mean velocity was measured using laser Doppler anemometry in a transparent vessel of diameter T = 400 mm, provided with a standard dished bottom. Three and six blade pitched blade impellers (the pitch angle varied within the interval a Îá24°; 45°ń of impeller/vessel diameter ratio D/T = 0.36, as well as a three blade pitched blade impeller with folded blades of the same diameter, were tested. The calculated results were compared with the results of experiments mentioned in the literature, above all in cylindrical vessels with a flat bottom. Both arrangements of the agitated system were described by the impeller energetic efficiency, i.e, a criterion including in dimensionless form both the impeller energy consumption (impeller power input and the impeller pumping effect (impeller pumping capacity. It follows from the results obtained with various geometrical configurations that the energetic efficiency of pitched blade impellers is significantly lower for configurations suitable for mixing solid-liquid suspensions (low impeller off bottom clearances than for blending miscible liquids in mixing (higher impeller off bottom clearances.

The effect of pitch in multislice spiral/helical CT

International Nuclear Information System (INIS)

Wang, G.; Vannier, M.W.

2000-01-01

The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the detector collimation, and the table increment per x-ray source rotation. The pitch in multislice spiral CT is defined as the ratio of the table increment over the detector collimation in this study. In parallel to the current framework for studying longitudinal image resolution, the central fan-beam rays of direct and opposite directions are considered, assuming a narrow cone-beam angle. Generally speaking, sampling in the Radon domain by the direct and opposite central rays is nonuniform along the longitudinal axis. Using a recently developed methodology for quantifying the sensibility of signal reconstruction from non-uniformly sampled finite points, the effect of pitch on raw data interpolation is analyzed in multislice spiral CT. Unlike single-slice spiral CT, in which image quality decreases monotonically as the pitch increases, the sensibility of raw data interpolation in multislice spiral CT increases, suggesting that image quality does not decrease monotonically in this case. The most favorable pitch can be found from the sensitivity-slice spiral CT is provided. The study on the effect of pitch using the sensitivity analysis approach reveals the fundamental characteristics of raw data interpolation in multislice spiral CT, and gives insights into interaction between pitch and image quality. These results may be valuable for design of multislice spiral CT scanners and imaging protocol optimization in clinical applications. (authors)

Repetitive model predictive approach to individual pitch control of wind turbines

DEFF Research Database (Denmark)

Adegas, Fabiano Daher; Stoustrup, Jakob; Odgaard, Peter Fogh

2011-01-01

prediction. As a consequence, individual pitch feed-forward control action is generated by the controller, taking ”future” wind disturbance into account. Information about the estimated wind spatial distribution one blade experience can be used in the prediction model to better control the next passing blade......Wind turbines are inherently exposed to nonuniform wind fields with of wind shear, tower shadow, and possible wake contributions. Asymmetrical aerodynamic rotor loads are a consequence of such periodic, repetitive wind disturbances experienced by the blades. A controller may estimate and use...... this peculiar disturbance pattern to better attenuate loads and regulate power by controlling the blade pitch angles individually. A novel model predictive (MPC) approach for individual pitch control of wind turbines is proposed in this paper. A repetitive wind disturbance model is incorporated into the MPC...

Vocal Pitch Shift in Congenital Amusia (Pitch Deafness)

Science.gov (United States)

Hutchins, Sean; Peretz, Isabelle

2013-01-01

We tested whether congenital amusics, who exhibit pitch perception deficits, nevertheless adjust the pitch of their voice in response to a sudden pitch shift applied to vocal feedback. Nine amusics and matched controls imitated their own previously-recorded speech or singing, while the online feedback they received was shifted mid-utterance by 25…

Experiments on the Performance of Small Horizontal Axis Wind Turbine with Passive Pitch Control by Disk Pulley

Directory of Open Access Journals (Sweden)

Yu-Jen Chen

2016-05-01

Full Text Available The present work is to design a passive pitch-control mechanism for small horizontal axis wind turbine (HAWT to generate stable power at high wind speeds. The mechanism uses a disk pulley as an actuator to passively adjust the pitch angle of blades by centrifugal force. For this design, aerodynamic braking is caused by the adjustment of pitch angles at high wind speeds. As a marked advantage, this does not require mechanical brakes that would incur electrical burn-out and structural failure under high speed rotation. This can ensure the survival of blades and generator in sever operation environments. In this paper, the analysis uses blade element momentum theory (BEMT to develop graphical user interface software to facilitate the performance assessment of the small-scale HAWT using passive pitch control (PPC. For verification, the HAWT system was tested in a full-scale wind tunnel for its aerodynamic performance. At low wind speeds, this system performed the same as usual, yet at high wind speeds, the equipped PPC system can effectively reduce the rotational speed to generate stable power.

Experimental Study of Tip Vortex Flow from a Periodically Pitched Airfoil Section

Science.gov (United States)

Zaman, Khairul; Fagan, Amy; Mankbadi, Mina

2016-01-01

An experimental investigation of tip vortex flow from a NACA0012 airfoil, pitched periodically at various frequencies, is conducted in a low-speed wind tunnel. Initially, data for stationary airfoil held fixed at various angles-of-attack are gathered. Flow visualization pictures as well as detailed cross-sectional properties areobtained at various streamwise locations using hot-wire anemometry. Data include mean velocity, streamwise vorticity as well as various turbulent stresses. Preliminary data are also acquired for periodically pitched airfoil. These results are briefly presented in this extended abstract.

Discrete Element Method Modeling of the Rheological Properties of Coke/Pitch Mixtures

Directory of Open Access Journals (Sweden)

Behzad Majidi

2016-05-01

Full Text Available Rheological properties of pitch and pitch/coke mixtures at temperatures around 150 °C are of great interest for the carbon anode manufacturing process in the aluminum industry. In the present work, a cohesive viscoelastic contact model based on Burger’s model is developed using the discrete element method (DEM on the YADE, the open-source DEM software. A dynamic shear rheometer (DSR is used to measure the viscoelastic properties of pitch at 150 °C. The experimental data obtained is then used to estimate the Burger’s model parameters and calibrate the DEM model. The DSR tests were then simulated by a three-dimensional model. Very good agreement was observed between the experimental data and simulation results. Coke aggregates were modeled by overlapping spheres in the DEM model. Coke/pitch mixtures were numerically created by adding 5, 10, 20, and 30 percent of coke aggregates of the size range of 0.297–0.595 mm (−30 + 50 mesh to pitch. Adding up to 30% of coke aggregates to pitch can increase its complex shear modulus at 60 Hz from 273 Pa to 1557 Pa. Results also showed that adding coke particles increases both storage and loss moduli, while it does not have a meaningful effect on the phase angle of pitch.

Effects of Culture on Musical Pitch Perception

Science.gov (United States)

Wong, Patrick C. M.; Ciocca, Valter; Chan, Alice H. D.; Ha, Louisa Y. Y.; Tan, Li-Hai; Peretz, Isabelle

2012-01-01

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association—the influence of linguistic background on music pitch processing and disorders—remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means ‘teacher’ and ‘to try’ when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture

Effects of culture on musical pitch perception.

Science.gov (United States)

Wong, Patrick C M; Ciocca, Valter; Chan, Alice H D; Ha, Louisa Y Y; Tan, Li-Hai; Peretz, Isabelle

2012-01-01

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture

Effects of culture on musical pitch perception.

Directory of Open Access Journals (Sweden)

Patrick C M Wong

Full Text Available The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively. Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages. This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population, we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of

Difficulties with Pitch Discrimination Influences Pitch Memory Performance: Evidence from Congenital Amusia

OpenAIRE

Jiang, Cunmei; Lim, Vanessa K.; Wang, Hang; Hamm, Jeff P.

2013-01-01

Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to crea...

Effects of grit roughness and pitch oscillations on the S810 airfoil

Energy Technology Data Exchange (ETDEWEB)

Ramsay, R.R.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-01-01

An S810 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from -20{degrees} to +40{degrees} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, the above conditions were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Baseline steady state results of the S810 testing showed a maximum lift coefficient of 1.15 at 15.2{degrees}angle of attack. The application of LEGR reduced the maximum lift coefficient by 12% and increased the 0.0085 minimum drag coefficient value by 88%. The zero lift pitching moment of -0.0286 showed a 16% reduction in magnitude to -0.0241 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {plus_minus}5.5{degrees} and {plus_minus}10{degrees}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude and both sets of unsteady maximum lift coefficients were greater than the steady state values. Stall was delayed on the airfoil while the angle of attack was increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. In addition to the hysteresis behavior, an unusual feature of these data were a sudden increase in the lift coefficient where the onset of stall was expected. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack.

Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia.

Science.gov (United States)

Jiang, Cunmei; Lim, Vanessa K; Wang, Hang; Hamm, Jeff P

2013-01-01

Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones) differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.

Performance analysis of a heat pipe solar collector having different pitch distance

Energy Technology Data Exchange (ETDEWEB)

Sivaraman, B.; Mohan, N.K. [Annamalai Univ., Tamil Nadu (India). Dept. of Mechanical Engineering

2006-07-01

Heat pipe solar collectors are more efficient than conventional solar collectors. This paper provided details of experimental analyses conducted to examine the effect of pitch distance on the heat pipe's performance. Two solar collectors with pitch distances of 7.5 cm and 8.5 cm were used in the study. Copper tubing was used as the container material, and methanol was selected as a working fluid for the experiments, which were conducted during the summer at a collector tilt angle of 11 degrees. Experiments were conducted and the impacts of various parameters were measured. Solar intensity was measured using a pyranometer. Water exit and inlet temperatures were measured using mercury thermometers. Results showed that the heat pipe performed optimally when the pitch distance was 0.085 m. 8 refs., 1 tab., 9 figs.

Pitch angle scattering and particle precipitation in a pulsating aurora - an experimental study

International Nuclear Information System (INIS)

Sandahl, I.

1984-10-01

A pulsating aurora occurring during the recovery phase of a substorm on January 27, 1979 was monitored by a large set of instruments. The Swedish sounding rocket S23-L2 was launched at magnetic midnight over pulsating patches, some of which exhibited 3+-1 Hz modulation. The ground based instrumentation included auroral TV cameras, all sky cameras, photometers and magnetometers. The geostationary satellite GEOS-2 was located in the equatorial plane, approximately conjugate to the rocket. The central experiment of this study is the particle experiment on the rocket. Several aspects of pulsating auroras have been investigated. The auroral luminosity variations were very well correlated to variations in the flux of precipitating hot electrons. The 1-20 second pulsations were caused by increased fluxes of 4-40 keV electrons. The 3+-1 Hz modulation was detected in 7-200 keV electrons, but the biggest energy flux modulation occurred for electrons of about 60 keV. Model calculations involving the electron distributions measured by the sounding rocket and GEOS-2, consistently show that the electrons may have been scattered into the loss cone through the Doppler shifted gyroresonance with whistler mode waves. The scattering was not a pure pitch angle scattering as in the classical Coroniti and Kennel theory, but involved also a systematic energy loss from the particles. The waves were probably hiss with some chorus elements. The equatorial plane plasma density was estimated in two independent ways to be about 2x10 6 m- 3 . The 3+-1 Hz modulation was measured both by the particle experiment on the rocket and by the wave experiment on GEOS-2. Properties of the modulated fluxes are described and a qualitative model for the cause of the modulation is proposed. (author)

Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia.

Directory of Open Access Journals (Sweden)

Cunmei Jiang

Full Text Available Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.

Feedback brake distribution control for minimum pitch

Science.gov (United States)

Tavernini, Davide; Velenis, Efstathios; Longo, Stefano

2017-06-01

The distribution of brake forces between front and rear axles of a vehicle is typically specified such that the same level of brake force coefficient is imposed at both front and rear wheels. This condition is known as 'ideal' distribution and it is required to deliver the maximum vehicle deceleration and minimum braking distance. For subcritical braking conditions, the deceleration demand may be delivered by different distributions between front and rear braking forces. In this research we show how to obtain the optimal distribution which minimises the pitch angle of a vehicle and hence enhances driver subjective feel during braking. A vehicle model including suspension geometry features is adopted. The problem of the minimum pitch brake distribution for a varying deceleration level demand is solved by means of a model predictive control (MPC) technique. To address the problem of the undesirable pitch rebound caused by a full-stop of the vehicle, a second controller is designed and implemented independently from the braking distribution in use. An extended Kalman filter is designed for state estimation and implemented in a high fidelity environment together with the MPC strategy. The proposed solution is compared with the reference 'ideal' distribution as well as another previous feed-forward solution.

Active tower damping and pitch balancing - design, simulation and field test

Science.gov (United States)

Duckwitz, Daniel; Shan, Martin

2014-12-01

The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine.

Establishment of expanded and streamlined pipeline of PITCh knock-in - a web-based design tool for MMEJ-mediated gene knock-in, PITCh designer, and the variations of PITCh, PITCh-TG and PITCh-KIKO.

Science.gov (United States)

Nakamae, Kazuki; Nishimura, Yuki; Takenaga, Mitsumasa; Nakade, Shota; Sakamoto, Naoaki; Ide, Hiroshi; Sakuma, Tetsushi; Yamamoto, Takashi

2017-05-04

The emerging genome editing technology has enabled the creation of gene knock-in cells easily, efficiently, and rapidly, which has dramatically accelerated research in the field of mammalian functional genomics, including in humans. We recently developed a microhomology-mediated end-joining-based gene knock-in method, termed the PITCh system, and presented various examples of its application. Since the PITCh system only requires very short microhomologies (up to 40 bp) and single-guide RNA target sites on the donor vector, the targeting construct can be rapidly prepared compared with the conventional targeting vector for homologous recombination-based knock-in. Here, we established a streamlined pipeline to design and perform PITCh knock-in to further expand the availability of this method by creating web-based design software, PITCh designer ( http://www.mls.sci.hiroshima-u.ac.jp/smg/PITChdesigner/index.html ), as well as presenting an experimental example of versatile gene cassette knock-in. PITCh designer can automatically design not only the appropriate microhomologies but also the primers to construct locus-specific donor vectors for PITCh knock-in. By using our newly established pipeline, a reporter cell line for monitoring endogenous gene expression, and transgenesis (TG) or knock-in/knockout (KIKO) cell line can be produced systematically. Using these new variations of PITCh, an exogenous promoter-driven gene cassette expressing fluorescent protein gene and drug resistance gene can be integrated into a safe harbor or a specific gene locus to create transgenic reporter cells (PITCh-TG) or knockout cells with reporter knock-in (PITCh-KIKO), respectively.

Comparison of the Calcaneal Pitch Angle and Modified Projection Area Per Length Squared Method for Medial Longitudinal Arch Evaluation of the Foot

Directory of Open Access Journals (Sweden)

Esat Kıter2

2012-12-01

Full Text Available Objective: To compare the calcaneal pitch angle (CPA values measured on direct lateral radiographs of feet, and the modified projection area per length squared (PAL, which was calculated as a new method for the evaluation of the medial longitudinal arch (MLA of the foot.Material and Methods: Direct lateral radiographs of patients who had weightbearing feet radiographies for any reason except trauma were retrospectively obtained from the archives. Direct lateral radiographs of the feet were printed and a transparent sheet was placed on it. A straight line was drawn between the most plantar process of the calcaneus and the head of the first metatarsal bone for the calculation of the PAL of the MLA. Two semilunar arcs were drawn upon this straight line. PAL1 and PAL2 were estimated using a point-counting technique. The CPA, lateral talo-calcaneal angles (LTCA, and talo-first metatarsal angles (TFMA were measured. The correlations between PAL1, PAL2 of right and left feet and CPA, LTCA, and TFMA were explored.Results: Fifty patients (27 females, 23 males with a mean age of 40.12 (4-78 years were evaluated. Significant correlations were detected between PAL1, PAL2 and CPA, and TFMA for both right and left feet (p<0.05. Conclusion: A significant correlation was detected between the modified PAL method as a new technique and the standard CPA method for MLA evaluation. The PAL method is suggested as a simple and practical method for MLA evaluation.

Control of Pan-tilt Mechanism Angle using Position Matrix Method

Directory of Open Access Journals (Sweden)

Hendri Maja Saputra

2013-12-01

Full Text Available Control of a Pan-Tilt Mechanism (PTM angle for the bomb disposal robot Morolipi-V2 using inertial sensor measurement unit, x-IMU, has been done. The PTM has to be able to be actively controlled both manually and automatically in order to correct the orientation of the moving Morolipi-V2 platform. The x-IMU detects the platform orientation and sends the result in order to automatically control the PTM. The orientation is calculated using the quaternion combined with Madwick and Mahony filter methods. The orientation data that consists of angles of roll (α, pitch (β, and yaw (γ from the x-IMU are then being sent to the camera for controlling the PTM motion (pan & tilt angles after calculating the reverse angle using position matrix method. Experiment results using Madwick and Mahony methods show that the x-IMU can be used to find the robot platform orientation. Acceleration data from accelerometer and flux from magnetometer produce noise with standard deviation of 0.015 g and 0.006 G, respectively. Maximum absolute errors caused by Madgwick and Mahony method with respect to Xaxis are 48.45º and 33.91º, respectively. The x-IMU implementation as inertia sensor to control the Pan-Tilt Mechanism shows a good result, which the probability of pan angle tends to be the same with yaw and tilt angle equal to the pitch angle, except a very small angle shift due to the influence of roll angle..

Imperfect pitch: Gabor's uncertainty principle and the pitch of extremely brief sounds.

Science.gov (United States)

Hsieh, I-Hui; Saberi, Kourosh

2016-02-01

How brief must a sound be before its pitch is no longer perceived? The uncertainty tradeoff between temporal and spectral resolution (Gabor's principle) limits the minimum duration required for accurate pitch identification or discrimination. Prior studies have reported that pitch can be extracted from sinusoidal pulses as brief as half a cycle. This finding has been used in a number of classic papers to develop models of pitch encoding. We have found that phase randomization, which eliminates timbre confounds, degrades this ability to chance, raising serious concerns over the foundation on which classic pitch models have been built. The current study investigated whether subthreshold pitch cues may still exist in partial-cycle pulses revealed through statistical integration in a time series containing multiple pulses. To this end, we measured frequency-discrimination thresholds in a two-interval forced-choice task for trains of partial-cycle random-phase tone pulses. We found that residual pitch cues exist in these pulses but discriminating them requires an order of magnitude (ten times) larger frequency difference than that reported previously, necessitating a re-evaluation of pitch models built on earlier findings. We also found that as pulse duration is decreased to less than two cycles its pitch becomes biased toward higher frequencies, consistent with predictions of an auto-correlation model of pitch extraction.

An imaging grating diffractometer for traceable calibration of grating pitch in the range 20 μm to 350 nm

International Nuclear Information System (INIS)

Brasil, D A; Alves, J A P; Pekelsky, J R

2015-01-01

This work describes the development of a grating diffratometer to provide traceable calibration of grating pitch in range 20 μm to 350 nm. The approach is based on the Littrow configuration in which a laser beam is directed onto the grating which is mounted on a rotary table and can be turned so that each selected diffraction order is retro-reflected in the laser incidence direction. A beamsplitter and a lens direct the reflected diffraction order to form a small image spot on a CCD camera and the spot centering is used to adjust to rotation angle, thereby giving the diffraction angle. Knowing the diffraction angle for several orders and the wavelength of the laser, the average grating pitch can be determined to an uncertainty the order of 14 pm. (paper)

Establishment of expanded and streamlined pipeline of PITCh knock-in – a web-based design tool for MMEJ-mediated gene knock-in, PITCh designer, and the variations of PITCh, PITCh-TG and PITCh-KIKO

Science.gov (United States)

Nakamae, Kazuki; Nishimura, Yuki; Takenaga, Mitsumasa; Sakamoto, Naoaki; Ide, Hiroshi; Sakuma, Tetsushi; Yamamoto, Takashi

2017-01-01

ABSTRACT The emerging genome editing technology has enabled the creation of gene knock-in cells easily, efficiently, and rapidly, which has dramatically accelerated research in the field of mammalian functional genomics, including in humans. We recently developed a microhomology-mediated end-joining-based gene knock-in method, termed the PITCh system, and presented various examples of its application. Since the PITCh system only requires very short microhomologies (up to 40 bp) and single-guide RNA target sites on the donor vector, the targeting construct can be rapidly prepared compared with the conventional targeting vector for homologous recombination-based knock-in. Here, we established a streamlined pipeline to design and perform PITCh knock-in to further expand the availability of this method by creating web-based design software, PITCh designer (http://www.mls.sci.hiroshima-u.ac.jp/smg/PITChdesigner/index.html), as well as presenting an experimental example of versatile gene cassette knock-in. PITCh designer can automatically design not only the appropriate microhomologies but also the primers to construct locus-specific donor vectors for PITCh knock-in. By using our newly established pipeline, a reporter cell line for monitoring endogenous gene expression, and transgenesis (TG) or knock-in/knockout (KIKO) cell line can be produced systematically. Using these new variations of PITCh, an exogenous promoter-driven gene cassette expressing fluorescent protein gene and drug resistance gene can be integrated into a safe harbor or a specific gene locus to create transgenic reporter cells (PITCh-TG) or knockout cells with reporter knock-in (PITCh-KIKO), respectively. PMID:28453368

Development of Gentle Slope Light Guide Structure in a 3.4 μm Pixel Pitch Global Shutter CMOS Image Sensor with Multiple Accumulation Shutter Technology.

Science.gov (United States)

Sekine, Hiroshi; Kobayashi, Masahiro; Onuki, Yusuke; Kawabata, Kazunari; Tsuboi, Toshiki; Matsuno, Yasushi; Takahashi, Hidekazu; Inoue, Shunsuke; Ichikawa, Takeshi

2017-12-09

CMOS image sensors (CISs) with global shutter (GS) function are strongly required in order to avoid image degradation. However, CISs with GS function have generally been inferior to the rolling shutter (RS) CIS in performance, because they have more components. This problem is remarkable in small pixel pitch. The newly developed 3.4 µm pitch GS CIS solves this problem by using multiple accumulation shutter technology and the gentle slope light guide structure. As a result, the developed GS pixel achieves 1.8 e - temporal noise and 16,200 e - full well capacity with charge domain memory in 120 fps operation. The sensitivity and parasitic light sensitivity are 28,000 e - /lx·s and -89 dB, respectively. Moreover, the incident light angle dependence of sensitivity and parasitic light sensitivity are improved by the gentle slope light guide structure.

Pitch discrimination learning: specificity for pitch and harmonic resolvability, and electrophysiological correlates.

Science.gov (United States)

Carcagno, Samuele; Plack, Christopher J

2011-08-01

Multiple-hour training on a pitch discrimination task dramatically decreases the threshold for detecting a pitch difference between two harmonic complexes. Here, we investigated the specificity of this perceptual learning with respect to the pitch and the resolvability of the trained harmonic complex, as well as its cortical electrophysiological correlates. We trained 24 participants for 12 h on a pitch discrimination task using one of four different harmonic complexes. The complexes differed in pitch and/or spectral resolvability of their components by the cochlea, but were filtered into the same spectral region. Cortical-evoked potentials and a behavioral measure of pitch discrimination were assessed before and after training for all the four complexes. The change in these measures was compared to that of two control groups: one trained on a level discrimination task and one without any training. The behavioral results showed that learning was partly specific to both pitch and resolvability. Training with a resolved-harmonic complex improved pitch discrimination for resolved complexes more than training with an unresolved complex. However, we did not find evidence that training with an unresolved complex leads to specific learning for unresolved complexes. Training affected the P2 component of the cortical-evoked potentials, as well as a later component (250-400 ms). No significant changes were found on the mismatch negativity (MMN) component, although a separate experiment showed that this measure was sensitive to pitch changes equivalent to the pitch discriminability changes induced by training. This result suggests that pitch discrimination training affects processes not measured by the MMN, for example, processes higher in level or parallel to those involved in MMN generation.

Coupled Rolling and Pitching Oscillation Effects on Transonic Shock-Induced Vortex-Breakdown Flow of a Delta Wing

Science.gov (United States)

Kandil, Osama A.; Menzies, Margaret A.

1996-01-01

Unsteady, transonic vortex dominated flow over a 65 deg. sharp edged, cropped-delta wing of zero thickness undergoing forced coupled pitching and rolling oscillations is investigated computationally. The wing mean angle of attack is 20 deg. and the free stream Mach number and Reynolds number are 0.85 and 3.23 x 10(exp 6), respectively. The initial condition of the flow is characterized by a transverse terminating shock and vortex breakdown of the leading edge vortex cores. The computational investigation uses the time-accurate solution of the laminar, unsteady, compressible, full Navier-Stokes equations with the implicit, upwind, Roe flux-difference splitting, finite volume scheme. The main focus is to analyze the effects of coupled motion on the wing response and vortex breakdown flow by varying oscillation frequency and phase angle while the maximum pitch and roll amplitude is kept constant at 4.0 deg. Four cases demonstrate the following: simultaneous motion at a frequency of 1(pi), motion with a 90 deg. phase lead in pitch, motion with a rolling frequency of twice the pitching frequency, and simultaneous motion at a frequency of 2(pi). Comparisons with single mode motion at these frequencies complete this study and illustrate the effects of coupling the oscillations.

Variable Pitch Approach for Performance Improving of Straight-Bladed VAWT at Rated Tip Speed Ratio

Directory of Open Access Journals (Sweden)

Zhenzhou Zhao

2018-06-01

Full Text Available This paper presents a new variable pitch (VP approach to increase the peak power coefficient of the straight-bladed vertical-axis wind turbine (VAWT, by widening the azimuthal angle band of the blade with the highest aerodynamic torque, instead of increasing the highest torque. The new VP-approach provides a curve of pitch angle designed for the blade operating at the rated tip speed ratio (TSR corresponding to the peak power coefficient of the fixed pitch (FP-VAWT. The effects of the new approach are exploited by using the double multiple stream tubes (DMST model and Prandtl’s mathematics to evaluate the blade tip loss. The research describes the effects from six aspects, including the lift, drag, angle of attack (AoA, resultant velocity, torque, and power output, through a comparison between VP-VAWTs and FP-VAWTs working at four TSRs: 4, 4.5, 5, and 5.5. Compared with the FP-blade, the VP-blade has a wider azimuthal zone with the maximum AoA, lift, drag, and torque in the upwind half-cycle, and yields the two new larger maximum values in the downwind half-cycle. The power distribution in the swept area of the turbine changes from an arched shape of the FP-VAWT into the rectangular shape of the VP-VAWT. The new VP-approach markedly widens the highest-performance zone of the blade in a revolution, and ultimately achieves an 18.9% growth of the peak power coefficient of the VAWT at the optimum TSR. Besides achieving this growth, the new pitching method will enhance the performance at TSRs that are higher than current optimal values, and an increase of torque is also generated.

Active tower damping and pitch balancing – design, simulation and field test

International Nuclear Information System (INIS)

Duckwitz, Daniel; Shan, Martin

2014-01-01

The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine

Reynolds number effect on airfoil wake structures under pitching and heaving motion

Science.gov (United States)

Kim, Kyung Chun; Karbasian, Hamidreza; ExpTENsys Team

2017-11-01

Detached Eddy Simulation (DES) and particle image velocimetry (PIV) measurements were performed to investigate the wake flow characteristics of an airfoil under pitching and heaving motion. A NACA0012 airfoil was selected for the numerical simulation and experiments were carried out in a wind tunnel and a water tunnel at Reynolds number of 15,000 and 90,000, respectively. The airfoil oscillated around an axis located 1/4 distance from the leading edge chord. Two different angles of attack, 20° and 30°, were selected with +/-10° maximum amplitude of oscillation. In order to extract the coherent flow structures from time-resolved PIV data, proper orthogonal decomposition (POD) analysis was performed on 1,000 instantaneous realisations for each condition using the method of snapshots. Vorticity contour and velocity profiles for both PIV and DES results are in good agreement for pitching and heaving motion. At high Reynolds number, 3D stream-wise vortices appeared after generating span-wise vortices. The higher maximum angle of attack allows the leading edge vortex to grow stronger and that the angle of attack appears to be more important in influencing the growth of the leading edge vortex structure than the reduced frequency. National Research Foundation of Korea (No. 2011-0030013).

Control design for a pitch-regulated, variable speed wind turbine

Energy Technology Data Exchange (ETDEWEB)

Hansen, M.H.; Hansen, A.; Larsen, T.J.; Oeye, S.; Soerensen, P.; Fuglsang, P.

2005-01-01

The three different controller designs presented herein are similar and all based on PI-regulation of rotor speed and power through the collective blade pitch angle and generator moment. The aeroelastic and electrical modelling used for the time-domain analysis of these controllers are however different, which makes a directly quantitative comparison difficult. But there are some observations of similar behaviours should be mentioned: 1) Very similar step responses in rotor speed, pitch angle, and power are seen for simulations with steps in wind speed. 2) All controllers show a peak in power for wind speed step-up over rated wind speed, which can be almost removed by changing the parameters of the frequency converter. 3) Responses of rotor speed, pitch angle, and power for different simulations with turbulent inflow are similar for all three controllers. Again, there seems to be an advantage of tuning the parameters of the frequency converter to obtain a more constant power output. The dynamic modelling of the power controller is an important result for the inclusion of generator dynamics in the aeroelastic modelling of wind turbines. A reduced dynamic model of the relation between generator torque and generator speed variations is presented; where the integral term of the inner PI-regulator of rotor current is removed be-cause the time constant is very small compared to the important aeroelastic frequencies. It is shown how the parameters of the transfer function for the remaining control system with the outer PI-regulator of power can be derived from the generator data sheet. The main results of the numerical optimisation of the control parameters in the pitch PI-regulator performed in Chapter 6 are the following: 1) Numerical optimization can be used to tune controller parameters, especially when the optimization is used as refinement of a qualified initial guess. 2) The design model used to calculate the initial value parameters, as described in Chapter 3

Evidence for shared cognitive processing of pitch in music and language.

Science.gov (United States)

Perrachione, Tyler K; Fedorenko, Evelina G; Vinke, Louis; Gibson, Edward; Dilley, Laura C

2013-01-01

Language and music epitomize the complex representational and computational capacities of the human mind. Strikingly similar in their structural and expressive features, a longstanding question is whether the perceptual and cognitive mechanisms underlying these abilities are shared or distinct--either from each other or from other mental processes. One prominent feature shared between language and music is signal encoding using pitch, conveying pragmatics and semantics in language and melody in music. We investigated how pitch processing is shared between language and music by measuring consistency in individual differences in pitch perception across language, music, and three control conditions intended to assess basic sensory and domain-general cognitive processes. Individuals' pitch perception abilities in language and music were most strongly related, even after accounting for performance in all control conditions. These results provide behavioral evidence, based on patterns of individual differences, that is consistent with the hypothesis that cognitive mechanisms for pitch processing may be shared between language and music.

Lung studies with spiral CT. pitch 1 versus pitch 2

International Nuclear Information System (INIS)

Sartoni Galloni, S.; Miceli, M.; Lipparino, M.; Burzi, M.; Gigli, F.; Rossi, M.S.; Santoli, G.; Guidarelli, G.

1999-01-01

In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality [it

Pitching motion control of a butterfly-like 3D flapping wing-body model

Science.gov (United States)

Suzuki, Kosuke; Minami, Keisuke; Inamuro, Takaji

2014-11-01

Free flights and a pitching motion control of a butterfly-like flapping wing-body model are numerically investigated by using an immersed boundary-lattice Boltzmann method. The model flaps downward for generating the lift force and backward for generating the thrust force. Although the model can go upward against the gravity by the generated lift force, the model generates the nose-up torque, consequently gets off-balance. In this study, we discuss a way to control the pitching motion by flexing the body of the wing-body model like an actual butterfly. The body of the model is composed of two straight rigid rod connected by a rotary actuator. It is found that the pitching angle is suppressed in the range of +/-5° by using the proportional-plus-integral-plus-derivative (PID) control for the input torque of the rotary actuator.

Theoretical analysis of Sloshing effect on Pitch Angel to optimize quick dive on litoral submarine 22 M

Science.gov (United States)

Sinaga, L. T. P.

2016-11-01

This study considers the analytic theoretical model. The Submarine was considered to be rigid body are free sailing model with various angle of attack to be quick dive as pitching motion. By using Floating Body Mechanism supported by analytic model to describe the theoretical model analisys test. For the case of fluid level on 30% of the front balast tank and various angle of pitch. The paper describes a study on Analytic theoretical and modeling in CFD (Computational Fluid Dynamics). For Analyzing at special care of sloshing on free surce ballast tank after peak and fore peak were taken into consideration. In general, both methods (analytic model and CFD model) demonstrated such a good agreement, particularly in the consistent trend of RAO.

Evaluation of the effect of anode groove pitch to ion beam focusibility on spherical plasma focus diode

Energy Technology Data Exchange (ETDEWEB)

Imanari, K [Oyama National College of Technology (Japan). Department of Electrical Engineering; Jiang, W; Masugata, K; Yatsui, K [Nagaoka Univ. of Technology (Japan). Laboratory of Beam Technology

1997-12-31

A new PIC simulation code was developed to evaluate the effect of anode plasma nonuniformity on LIB focusibility. The plasma nonuniformity was modelled by inducing anode grooves in the code. In the experimental conditions, groove pitch about 2.2 mm and groove width of 1.0 mm, the simulation results are in a good agreement with the observed data. At a groove pitch of 2.4 mm, the local divergence was very small, although the focal length was very long. It was inferred that the focusibility of SPFD will be determined by the z-deflection angle rather than the local divergence angle. Modification of the anode curvature may be advantageous to get a higher power density on the focal point. (author). 6 figs., 3 refs.

Pitch Discrimination Learning: Specificity for Pitch and Harmonic Resolvability, and Electrophysiological Correlates

OpenAIRE

Carcagno, Samuele; Plack, Christopher J.

2011-01-01

Multiple-hour training on a pitch discrimination task dramatically decreases the threshold for detecting a pitch difference between two harmonic complexes. Here, we investigated the specificity of this perceptual learning with respect to the pitch and the resolvability of the trained harmonic complex, as well as its cortical electrophysiological correlates. We trained 24 participants for 12 h on a pitch discrimination task using one of four different harmonic complexes. The complexes differed...

Pitch memory and exposure effects.

Science.gov (United States)

Ben-Haim, Moshe Shay; Eitan, Zohar; Chajut, Eran

2014-02-01

Recent studies indicate that the ability to represent absolute pitch values in long-term memory, long believed to be the possession of a small minority of trained musicians endowed with "absolute pitch," is in fact shared to some extent by a considerable proportion of the population. The current study examined whether this newly discovered ability affects aspects of music and auditory cognition, particularly pitch learning and evaluation. Our starting points are two well-established premises: (1) frequency of occurrence has an influence on the way we process stimuli; (2) in Western music, some pitches and musical keys are much more frequent than others. Based on these premises, we hypothesize that if absolute pitch values are indeed represented in long-term memory, pitch frequency of occurrence in music would significantly affect cognitive processes, in particular pitch learning and evaluation. Two experiments were designed to test this hypothesis in participants with no absolute pitch, most with little or no musical training. Experiment 1 demonstrated a faster response and a learning advantage for frequent pitches over infrequent pitches in an identification task. In Experiment 2, participants evaluated infrequent pitches as more pleasing than frequent pitches when presented in isolation. These results suggest that absolute pitch representation in memory may play a substantial, hitherto unacknowledged role in auditory (and specifically musical) cognition. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Pumping Capacity of Pitched Blade Impellers in a Tall Vessel with a Draught Tube

Directory of Open Access Journals (Sweden)

J. Brož

2004-01-01

Full Text Available A study was made of the pumping capacity of pitched blade impellers (two, three, four, five and six blade pitched blade impellers with pitch angles α = 35° and 45° coaxially located in a cylindrical pilot plant vessel with cylindrical draught tube provided with a standard dished bottom. The draught tube was equipped with four equally spaced radial baffles above the impeller pumping liquid upwards towards the liquid surface. In all investigated cases the liquid aspect ratio H/T = 1.2 - 1.5, the draught tube / vessel diameter ratios DT /T = 0.2 and 0.4 and the impeller / draught tube diameter ratio D/DT = 0.875. The pumping capacity of the impeller was calculated from the radial profile of the axial component of the mean velocity in the draught tube below the impeller at such an axial distance from the impeller that the rotor does not affect the vorticity of the flow. The mean velocity was measured using a laser Doppler anemometer with forward scatter mode in a transparent draught tube and a transparent vessel of diameter T = 400 mm. Two series of experiments were performed, both of them under a turbulent regime of flow of the agitated liquid. First, the optimum height of the dished bottom was sought, and then the dependences of the dimensionless flow rate criterion and the impeller power number on the number of impeller blades were determined for both pitch angles tested under conditions of optimum ratio HT /DT. It follows from the results of the experiments that the optimum ratio HT /DT = 0.25 when the cross sectional areas of the horizontal flow around the bottom and the vertical inflow to the draught tube are the same. For all the tested pitched blade impellers the impeller power number when α = 45° exceeds the value of this quantity when pitch angle α  =   35°, while the flow rate number when α = 35° exceeds this quantity when α = 45°. On the other hand, the absolute values of the impeller power number when the draught tube was

Effects of grit roughness and pitch oscillations on the S814 airfoil

Energy Technology Data Exchange (ETDEWEB)

Janiszewska, J.M.; Ramsay, R.R.; Hoffmann, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-07-01

Horizontal-axis wind turbine rotors experience unsteady aerodynamics when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the design of new rotor airfoils. The rotors also experience performance degradation due to surface roughness. These surface irregularities are due to the accumulation of insect debris, ice, and/or the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can also be used to validate analytical computer codes. An S814 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 X 5 subsonic wind tunnel (3 X 5) under steady flow with both stationary model conditions and pitch oscillations. To study the extent of performance loss due to surface roughness, a leading edge grit roughness pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, 1.25 and 1.5 million, while the angle of attack ranged from -20{degrees} to +40{degrees}. While the model underwent pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.5 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions {+-}5.5{degrees} and {+-}10{degrees}, were used; at mean angles of attack of 8{degrees}, 14{degrees}, and 20{degrees}. For purposes herein, any reference to unsteady conditions means the model was in pitch oscillation.

Effects of grit roughness and pitch oscillations on the S801 airfoil

Energy Technology Data Exchange (ETDEWEB)

Ramsay, R.R.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-01-01

Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are due to the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S801 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3x5 subsonic wind tunnel (3x5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions were 0.75, 1, 1.25, and 1.5 million, while the angle of attack ranged from -20{degrees} to +40{degrees}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used, {plus_minus} 5.5 {degrees}and {plus_minus} 10{degrees}, at mean angles of attack of 8{degrees} 14{degrees} and 20{degrees} For purposes herein, any reference to unsteady conditions means that the airfoil model was in pitch oscillation about the quarter chord.

Effects of grit roughness and pitch oscillations on the S815 airfoil

Energy Technology Data Exchange (ETDEWEB)

Reuss Ramsay, R.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-07-01

Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are cause by the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S815 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 x 5 subsonic wind tunnel (3 x 5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions were 0.75, 1, 1.25, and 1.4 million, while the angle of attack ranged from {minus}20{degree} to +40{degree}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {+-}5.5{degree} and {+-}10{degree}, at mean angles of attack of 8{degree}, 14{degree}, and 20{degree}. For purposes herein, any reference to unsteady conditions means that the model was in pitch oscillation about the quarter chord.

Pitch-verticality and pitch-size cross-modal interactions

DEFF Research Database (Denmark)

Bonetti, Leonardo; Costa, Marco

2017-01-01

Two studies were conducted on cross-modal matching between pitch and sound source localization on the vertical axis, and pitch and size. In the first study 100 Hz, 200 Hz, 600 Hz, and 800 Hz tones were emitted by a loudspeaker positioned 60 cm above or below to the participant’s ear level. Using...

Softball Pitching and Injury.

Science.gov (United States)

Lear, Aaron; Patel, Niraj

2016-01-01

The windmill softball pitch generates considerable forces about the athlete's shoulder and elbow. The injury pattern of softball pitchers seems to be primarily overuse injury, and they seem not to suffer the same volume of injury that baseball pitchers do. This article will explore softball pitching techniques, kinetics and kinematics of the windmill pitch, epidemiology of softball pitchers, and discuss possible etiologies of softball pitching injuries.

Factors affecting relative pitch perception

OpenAIRE

McClaskey, Carolyn Marie

2016-01-01

Sounds that evoke a sense of pitch are ubiquitous in our environment and important for speech, music, and auditory scene analysis. The frequencies of these sounds rarely remain constant, however, and the direction and extent of pitch change is often more important than the exact pitches themselves. This dissertation examines the mechanisms underlying how we perceive relative pitch distance, focusing on two types of stimuli: continuous pitch changes and discrete pitch changes. In a series of e...

Interaction of Energetic Particles with Discontinuities Upstream of Strong Shocks

Science.gov (United States)

Malkov, Mikhail; Diamond, Patrick

2008-11-01

Acceleration of particles in strong astrophysical shocks is known to be accompanied and promoted by a number of instabilities which are driven by the particles themselves. One of them is an acoustic (also known as Drury's) instability driven by the pressure gradient of accelerated particles upstream. The generated sound waves naturally steepen into shocks thus forming a shocktrain. Similar magnetoacoustic or Alfven type structures may be driven by pick-up ions, for example. We consider the solutions of kinetic equation for accelerated particles within the shocktrain. The accelerated particles are assumed to be coupled to the flow by an intensive pitch-angle scattering on the self-generated Alfven waves. The implications for acceleration and confinement of cosmic rays in this shock environment will be discussed.

Self-optimizing Pitch Control for Large Scale Wind Turbine Based on ADRC

Science.gov (United States)

Xia, Anjun; Hu, Guoqing; Li, Zheng; Huang, Dongxiao; Wang, Fengxiang

2018-01-01

Since wind turbine is a complex nonlinear and strong coupling system, traditional PI control method can hardly achieve good control performance. A self-optimizing pitch control method based on the active-disturbance-rejection control theory is proposed in this paper. A linear model of the wind turbine is derived by linearizing the aerodynamic torque equation and the dynamic response of wind turbine is transformed into a first-order linear system. An expert system is designed to optimize the amplification coefficient according to the pitch rate and the speed deviation. The purpose of the proposed control method is to regulate the amplification coefficient automatically and keep the variations of pitch rate and rotor speed in proper ranges. Simulation results show that the proposed pitch control method has the ability to modify the amplification coefficient effectively, when it is not suitable, and keep the variations of pitch rate and rotor speed in proper ranges

Perfect pitch reconsidered.

Science.gov (United States)

Moulton, Calum

2014-10-01

Perfect pitch, or absolute pitch (AP), is defined as the ability to identify or produce the pitch of a sound without need for a reference pitch, and is generally regarded as a valuable asset to the musician. However, there has been no recent review of the literature examining its aetiology and its utility taking into account emerging scientific advances in AP research, notably in functional imaging. This review analyses the key empirical research on AP, focusing on genetic and neuroimaging studies. The review concludes that: AP probably has a genetic predisposition, although this is based on limited evidence; early musical training is almost certainly essential for AP acquisition; and, although there is evidence that it may be relevant to speech processing, AP can interfere with relative pitch, an ability on which humans rely to communicate effectively. The review calls into question the value of AP to musicians and non-musicians alike. © 2014 Royal College of Physicians.

Perceptual pitch deficits coexist with pitch production difficulties in music but not Mandarin speech

Science.gov (United States)

Yang, Wu-xia; Feng, Jie; Huang, Wan-ting; Zhang, Cheng-xiang; Nan, Yun

2014-01-01

Congenital amusia is a musical disorder that mainly affects pitch perception. Among Mandarin speakers, some amusics also have difficulties in processing lexical tones (tone agnosics). To examine to what extent these perceptual deficits may be related to pitch production impairments in music and Mandarin speech, eight amusics, eight tone agnosics, and 12 age- and IQ-matched normal native Mandarin speakers were asked to imitate music note sequences and Mandarin words of comparable lengths. The results indicated that both the amusics and tone agnosics underperformed the controls on musical pitch production. However, tone agnosics performed no worse than the amusics, suggesting that lexical tone perception deficits may not aggravate musical pitch production difficulties. Moreover, these three groups were all able to imitate lexical tones with perfect intelligibility. Taken together, the current study shows that perceptual musical pitch and lexical tone deficits might coexist with musical pitch production difficulties. But at the same time these perceptual pitch deficits might not affect lexical tone production or the intelligibility of the speech words that were produced. The perception-production relationship for pitch among individuals with perceptual pitch deficits may be, therefore, domain-dependent. PMID:24474944

Perceptual Pitch Deficits Coexist with Pitch Production Difficulties in Music but Not Mandarin Speech

Directory of Open Access Journals (Sweden)

Wu-xia eYang

2014-01-01

Full Text Available Congenital amusia is a musical disorder that mainly affects pitch perception. Among Mandarin speakers, some amusics also have difficulties in processing lexical tones (tone agnosics. To examine to what extent these perceptual deficits may be related to pitch production impairments in music and Mandarin speech, 8 amusics, 8 tone agnosics, and 12 age- and IQ-matched normal native Mandarin speakers were asked to imitate music note sequences and Mandarin words of comparable lengths. The results indicated that both the amusics and tone agnosics underperformed the controls on musical pitch production. However, tone agnosics performed no worse than the amusics, suggesting that lexical tone perception deficits may not aggravate musical pitch production difficulties. Moreover, these three groups were all able to imitate lexical tones with perfect intelligibility. Taken together, the current study shows that perceptual musical pitch and lexical tone deficits might coexist with musical pitch production difficulties. But at the same time these perceptual pitch deficits might not affect lexical tone production or the intelligibility of the speech words that were produced. The perception-production relationship for pitch among individuals with perceptual pitch deficits may be, therefore, domain-dependent.

Perceiving pitch absolutely: Comparing absolute and relative pitch possessors in a pitch memory task

Directory of Open Access Journals (Sweden)

Schlaug Gottfried

2009-08-01

Full Text Available Abstract Background The perceptual-cognitive mechanisms and neural correlates of Absolute Pitch (AP are not fully understood. The aim of this fMRI study was to examine the neural network underlying AP using a pitch memory experiment and contrasting two groups of musicians with each other, those that have AP and those that do not. Results We found a common activation pattern for both groups that included the superior temporal gyrus (STG extending into the adjacent superior temporal sulcus (STS, the inferior parietal lobule (IPL extending into the adjacent intraparietal sulcus (IPS, the posterior part of the inferior frontal gyrus (IFG, the pre-supplementary motor area (pre-SMA, and superior lateral cerebellar regions. Significant between-group differences were seen in the left STS during the early encoding phase of the pitch memory task (more activation in AP musicians and in the right superior parietal lobule (SPL/intraparietal sulcus (IPS during the early perceptual phase (ITP 0–3 and later working memory/multimodal encoding phase of the pitch memory task (more activation in non-AP musicians. Non-significant between-group trends were seen in the posterior IFG (more in AP musicians and the IPL (more anterior activations in the non-AP group and more posterior activations in the AP group. Conclusion Since the increased activation of the left STS in AP musicians was observed during the early perceptual encoding phase and since the STS has been shown to be involved in categorization tasks, its activation might suggest that AP musicians involve categorization regions in tonal tasks. The increased activation of the right SPL/IPS in non-AP musicians indicates either an increased use of regions that are part of a tonal working memory (WM network, or the use of a multimodal encoding strategy such as the utilization of a visual-spatial mapping scheme (i.e., imagining notes on a staff or using a spatial coding for their relative pitch height for pitch

Hemispheric lateralization for early auditory processing of lexical tones: dependence on pitch level and pitch contour.

Science.gov (United States)

Wang, Xiao-Dong; Wang, Ming; Chen, Lin

2013-09-01

In Mandarin Chinese, a tonal language, pitch level and pitch contour are two dimensions of lexical tones according to their acoustic features (i.e., pitch patterns). A change in pitch level features a step change whereas that in pitch contour features a continuous variation in voice pitch. Currently, relatively little is known about the hemispheric lateralization for the processing of each dimension. To address this issue, we made whole-head electrical recordings of mismatch negativity in native Chinese speakers in response to the contrast of Chinese lexical tones in each dimension. We found that pre-attentive auditory processing of pitch level was obviously lateralized to the right hemisphere whereas there is a tendency for that of pitch contour to be lateralized to the left. We also found that the brain responded faster to pitch level than to pitch contour at a pre-attentive stage. These results indicate that the hemispheric lateralization for early auditory processing of lexical tones depends on the pitch level and pitch contour, and suggest an underlying inter-hemispheric interactive mechanism for the processing. © 2013 Elsevier Ltd. All rights reserved.

Pitch structure, but not selective attention, affects accent weightings in metrical grouping.

Science.gov (United States)

Prince, Jon B

2014-10-01

Among other cues, pitch and temporal accents contribute to grouping in musical sequences. However, exactly how they combine remains unclear, possibly because of the role of structural organization. In 3 experiments, participants rated the perceived metrical grouping of sequences that either adhered to the rules of tonal Western musical pitch structure (musical key) or did not (atonal). The tonal status of sequences did not provide any grouping cues and was irrelevant to the task. Experiment 1 established equally strong levels of pitch leap accents and duration accents in baseline conditions, which were then recombined in subsequent experiments. Neither accent type was stronger or weaker for tonal and atonal contexts. In Experiment 2, pitch leap accents dominated over duration accents, but the extent of this advantage was greater when sequences were tonal. Experiment 3 ruled out an attentional origin of this effect by replicating this finding while explicitly manipulating attention to pitch or duration accents between participant groups. Overall, the presence of tonal pitch structure made the dimension of pitch more salient at the expense of time. These findings support a dimensional salience framework in which the presence of organizational structure prioritizes the processing of the more structured dimension regardless of task relevance, independent from psychophysical difficulty, and impervious to attentional allocation.

Estimation of bearing contact angle in-situ by X-ray kinematography

Science.gov (United States)

Fowler, P. H.; Manders, F.

1982-01-01

The mounted, preloaded contact angle of the structural bearings in the assembled design mechanical assembly was measured. A modification of the Turns method is presented, based upon the clarity and definition of moving parts achieved with X-ray technique and cinematic display. Contact angle is estimated by counting the number of bearings passing a given point as a function of number of turns of the shaft. Ball and pitch diameter variations are discussed. Ball train and shaft angle uncertainties are also discussed.

Influence of musical expertise and musical training on pitch processing in music and language.

Science.gov (United States)

Besson, Mireille; Schön, Daniele; Moreno, Sylvain; Santos, Andréia; Magne, Cyrille

2007-01-01

We review a series of experiments aimed at studying pitch processing in music and speech. These studies were conducted with musician and non musician adults and children. We found that musical expertise improved pitch processing not only in music but also in speech. Demonstrating transfer of training between music and language has interesting applications for second language learning. We also addressed the issue of whether the positive effects of musical expertise are linked with specific predispositions for music or with extensive musical practice. Results of longitudinal studies argue for the later. Finally, we also examined pitch processing in dyslexic children and found that they had difficulties discriminating strong pitch changes that are easily discriminate by normal readers. These results argue for a strong link between basic auditory perception abilities and reading abilities. We used conjointly the behavioral method (Reaction Times and error rates) and the electrophysiological method (recording of the changes in brain electrical activity time-locked to stimulus presentation, Event-Related brain Potentials or ERPs). A set of common processes may be responsible for pitch processing in music and in speech and these processes are shaped by musical practice. These data add evidence in favor of brain plasticity and open interesting perspectives for the remediation of dyslexia using musical training.

Flight test of the X-29A at high angle of attack: Flight dynamics and controls

Science.gov (United States)

Bauer, Jeffrey E.; Clarke, Robert; Burken, John J.

1995-01-01

The NASA Dryden Flight Research Center has flight tested two X-29A aircraft at low and high angles of attack. The high-angle-of-attack tests evaluate the feasibility of integrated X-29A technologies. More specific objectives focus on evaluating the high-angle-of-attack flying qualities, defining multiaxis controllability limits, and determining the maximum pitch-pointing capability. A pilot-selectable gain system allows examination of tradeoffs in airplane stability and maneuverability. Basic fighter maneuvers provide qualitative evaluation. Bank angle captures permit qualitative data analysis. This paper discusses the design goals and approach for high-angle-of-attack control laws and provides results from the envelope expansion and handling qualities testing at intermediate angles of attack. Comparisons of the flight test results to the predictions are made where appropriate. The pitch rate command structure of the longitudinal control system is shown to be a valid design for high-angle-of-attack control laws. Flight test results show that wing rock amplitude was overpredicted and aileron and rudder effectiveness were underpredicted. Flight tests show the X-29A airplane to be a good aircraft up to 40 deg angle of attack.

The Effects of Inlet Box Aerodynamics on the Mechanical Performance of a Variable Pitch in Motion Fan

Directory of Open Access Journals (Sweden)

A. G. Sheard

2012-01-01

Full Text Available This paper describes research involving an in-service failure of a “variable pitch in motion” fan’s blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addressed two separate, but linked, needs. First, the ongoing need to increase fan pressure development capability required an increase in fan loading. This increase was within the context of an erosive operating regime which systematically reduced fan pressure development capability. The second need was to identify the root cause of blade-bearing failures. The author addressed the linked needs using a computational analysis, improving the rotor inflow aerodynamic characteristics through an analysis of the inlet box and design of inlet guide vanes to control flow nonuniformities at the fan inlet. The results of the improvement facilitated both an increase in fan-pressure-developing capability and identification of the root cause of the blade-bearing failures.

Self-propelled heaving and pitching flexible fin in a quiescent flow

International Nuclear Information System (INIS)

Kim, Boyoung; Park, Sung Goon; Huang, Weixi; Sung, Hyung Jin

2016-01-01

Highlights: • A self-propelled flexible fin with heaving and pitching motions in a quiescent flow has been simulated by using the penalty immersed boundary method. • The cruising speed and the swimming efficiency of the self-propelled fin were determined as functions of the bending coefficient (γ), the heaving amplitude (A_h). • We optimized the cruising speed and the swimming efficiency with respect to γ, f, A_h, A_p, and Δϕ. - Abstract: A self-propelled flexible fin with heaving and pitching motions in a quiescent flow has been simulated by using the penalty immersed boundary method. The flexible fin can move freely in the horizontal direction and the body of the flexible fin moves passively along with the active head motion. The position of the head of the fin was described as a harmonic heaving oscillation in the vertical direction, while the inclination angle of the head was prescribed as a harmonic oscillation with a moving clamped condition for the heaving and pitching fin. The cruising speed and the swimming efficiency of the self-propelled fin were determined as functions of the bending stiffness (γ), the heaving amplitude (A_h), the pitching amplitude (A_p), the flapping frequency (f) and the phase difference (Δϕ) between A_h and A_p. We optimized the cruising speed and the swimming efficiency with respect to γ, f, A_h, A_p and Δϕ. For a certain range of A_p, the swimming efficiency of the heaving and pitching fin is larger than that of a heaving-only fin.

Trunk Muscle Function Deficit in Youth Baseball Pitchers With Excessive Contralateral Trunk Tilt During Pitching.

Science.gov (United States)

Oyama, Sakiko; Waldhelm, Andrew G; Sosa, Araceli R; Patel, Ravina R; Kalinowski, Derick L

2017-09-01

Pitching technique is one of many factors that affect injury risk. Exhibiting excessive contralateral trunk tilt (CLT) during pitching has been linked to higher ball speed but also to increased joint loading. Deficit in trunk muscle strength has been suggested as an underlying cause of this movement pattern. The purpose of the study was to compare trunk muscle strength between youth baseball pitchers with varying degree of CLT during pitching. Cross-sectional study. Baseball practice fields. Twenty-eight youth baseball pitchers. Pitching technique was captured using a video camera. Based on the 2-dimensional trunk contralateral flexion angle, pitchers were categorized into low (30 degrees) CLT groups. Maximum isometric strength tests for trunk flexion, extension, and bilateral rotation, measured using a dynamometer. The pitchers with high CLT (n = 10) had longer pitching experience (P = 0.014), produced higher ball speed (P = 0.003) compared with the pitchers with moderate (n = 10) and low (n = 8) CLT, but demonstrated greater asymmetry in trunk rotation strength (relative weakness in rotation strength toward dominant side) compared with the pitchers with low CLT (P = 0.015). Excessive CLT may be a strategy that young pitchers learn to achieve higher ball velocity but also may be associated with imbalance between the oblique muscles on dominant and nondominant side, which may be acquired from repetitive pitching. Strengthening and emphasizing the use of dominant side oblique muscles may keep pitchers from leaning excessively during pitching and thus decrease joint loading.

Simulation model of a wind turbine pitch controller for grid frequency stabilisation

Energy Technology Data Exchange (ETDEWEB)

Jauch, Clemens; Cronin, Tom

2005-06-15

This paper describes a pitch angle controller that enables an active-stall wind turbine to dampen actively grid frequency oscillations. This builds on previous work in the area of the transient stability control of active-stall turbines. The phenomenon of grid frequency oscillations is explained briefly and then the task for the wind turbine controller defined. The pitch controller that acts as a grid frequency stabiliser is explained in terms of its layout, control sequence and parameters. Finally, a transient fault situation with subsequent grid frequency oscillations is simulated and it is shown how the grid frequency stabiliser works. The performance of the controller is discussed and the conclusion is drawn that grid frequency stabilisation with an active-stall turbine is possible under certain conditions. (Author)

Pitch-to-Pitch Correlation in Location, Velocity, and Movement ant Its Role in Predicting Strikeout Rate

OpenAIRE

Zhao, Shiyuan

2015-01-01

We evaluate a model for pitch sequencing in baseball that is defined by pitch-to-pitch correlation in location, velocity, and movement. The correlations quantify the average similarity of consecutive pitches and provide a measure of the batter's ability to predict the properties of the upcoming pitch. We examine the characteristics of the model for a set of major league pitchers using PITCHf/x data for nearly three million pitches thrown over seven major league seasons. After partitioning the...

Evaluating the pitch bias of CryoSat exploiting stacks of single look ehoes

Science.gov (United States)

Scagliola, Michele; Tagliani, Nicolas; Fornari, Marco; Bouzinac, Catherine; Parrinello, Tommaso

2014-05-01

CryoSat was launched on the 8th April 2010 and it is the first European ice mission dedicated to monitoring precise changes in the thickness of polar ice sheets and floating sea ice over a 3-year period. CryoSat carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. The attitude information of the spacecraft is provided by star trackers, that have an internal accuracy of few arc-seconds. By analysis of the CryoSat products, two different studies [1, 2] verified the existence of a bias between the pitch reported by the star trackers and the actual pitch of CryoSat during its flight. However those studies, that use two different methods to evaluate the actual pitch, provided different values for the pitch bias. This poster is aimed at describing a further method to estimated the pitch with which the satellite is actually flying by analysis of the stacks of the single look echoes that are accumulated for a given location of sea surface during the Level1 processing. In fact, over ocean the power of the single look echoes for a given point is shaped by the along-track antenna pattern. As a consequence, estimating the angular direction of pointing of the antenna from the stack, an estimate of the pitch can be obtained. Finally, the bias evaluated starting from the pitch measured with the proposed method is compared with the pitch bias measured in [1, 2]. [1] Galin,N. and Wingham, D., Estimating Pitch Angle of CryoSat-2 using the Power Distribution of the Synthetic Aperture, presented at SAR Altimetry Expert Group Meeting, Southampton UK, June 25-27, 2013. [2] Smith, W.H.F. and Scharroo, R., Retracking range, SWH, sigma-naught, and attitude in CryoSat conventional ocean data. In proceedings of Ocean Surface Topography Science Team Meeting. San Diego, October 19-21, 2011.

Understanding the unsteady aerodynamics of a revolving wing with pitching-flapping perturbations

Science.gov (United States)

Chen, Long; Wu, Jianghao; Zhou, Chao; Hsu, Shih-Jung; Eslam Panah, Azar; Cheng, Bo

2017-11-01

Revolving wings become less efficient for lift generation at low Reynolds numbers. Unlike flying insects using reciprocating revolving wings to exploit unsteady mechanisms for lift enhancement, an alternative that introduces unsteadiness through vertical flapping perturbation, is studied via experiments and simulations. Substantial drag reduction, linearly dependent on Strouhal number, is observed for a flapping-perturbed revolving wing at zero angle of attack (AoA), which can be explained by changes in the effective angle of attack and formation of reverse Karman vortex streets. When the AoA increases, flapping perturbations improve the maximum lift coefficient attainable by the revolving wing, with minor increases of drag or even minor drag reductions depending on Strouhal number and normalized flapping amplitude. When the pitching perturbations are further introduced, more substantial drag reduction and lift enhancement can be achieved in zero and positive AoAs, respectively. As the flapping-perturbed wings are less efficient compared with revolving wings in terms of power loading, the pitching-flapping perturbations can achieve a higher power loading at 20°AoA and thus have potential applications in micro air vehicle designs. This research was supported by NSF, DURIP, NSFC and Penn State Multi-Campus SEED Grant.

Left-hemisphere activation is associated with enhanced vocal pitch error detection in musicians with absolute pitch

Science.gov (United States)

Behroozmand, Roozbeh; Ibrahim, Nadine; Korzyukov, Oleg; Robin, Donald A.; Larson, Charles R.

2014-01-01

The ability to process auditory feedback for vocal pitch control is crucial during speaking and singing. Previous studies have suggested that musicians with absolute pitch (AP) develop specialized left-hemisphere mechanisms for pitch processing. The present study adopted an auditory feedback pitch perturbation paradigm combined with ERP recordings to test the hypothesis whether the neural mechanisms of the left-hemisphere enhance vocal pitch error detection and control in AP musicians compared with relative pitch (RP) musicians and non-musicians (NM). Results showed a stronger N1 response to pitch-shifted voice feedback in the right-hemisphere for both AP and RP musicians compared with the NM group. However, the left-hemisphere P2 component activation was greater in AP and RP musicians compared with NMs and also for the AP compared with RP musicians. The NM group was slower in generating compensatory vocal reactions to feedback pitch perturbation compared with musicians, and they failed to re-adjust their vocal pitch after the feedback perturbation was removed. These findings suggest that in the earlier stages of cortical neural processing, the right hemisphere is more active in musicians for detecting pitch changes in voice feedback. In the later stages, the left-hemisphere is more active during the processing of auditory feedback for vocal motor control and seems to involve specialized mechanisms that facilitate pitch processing in the AP compared with RP musicians. These findings indicate that the left hemisphere mechanisms of AP ability are associated with improved auditory feedback pitch processing during vocal pitch control in tasks such as speaking or singing. PMID:24355545

Why Pteropods Flap Their Wings, Periodically Pitch Their Shell, and Swim in a Sawtooth-like Trajectory

Science.gov (United States)

Adhikari, D.; Webster, D. R.; Yen, J.

2016-02-01

Antarctic pteropods (Limacina helicina antarctica), which are currently threatened by ocean acidification, swim in seawater with a pair of gelatinous parapodia (or "wings") via a distinctive propulsion mechanism. By flapping their parapodia in a way that resembles insect flight, they exhibit a unique shell wobble (or periodic shell pitching) motion and sawtooth-like trajectory. We present three-dimensional kinematics and volumetric fluid velocity fields for upward-swimming pteropods. Time-resolved data were collected with a unique infrared tomographic particle image velocimetry (tomo-PIV) system that was transported to Palmer Station, Antarctica. Both power and recovery strokes of the parapodia propel the pteropod (1.5 - 5 mm in size) upward in a sawtooth-like trajectory with average speed of 14 - 30 mm/s and periodically pitch the shell at 1.9 - 3 Hz with up to 110° difference in pitching angle. The pitch motion effectively positions the parapodia such that they stroke downward during both the power and recovery strokes. We use the kinematics measurement to illustrate the relationship between flapping, swimming and pitching, where the corresponding Reynolds numbers (i.e. Ref, ReU, and ReΩ) characterize the motion of the pteropod. For example, when Ref aquatic variations.

Study of Wave-Particle Interactions for Whistler Mode Waves at Oblique Angles by Utilizing the Gyroaveraging Method

Science.gov (United States)

Hsieh, Yi-Kai; Omura, Yoshiharu

2017-10-01

We investigate the properties of whistler mode wave-particle interactions at oblique wave normal angles to the background magnetic field. We find that electromagnetic energy of waves at frequencies below half the electron cyclotron frequency can flow nearly parallel to the ambient magnetic field. We thereby confirm that the gyroaveraging method, which averages the cyclotron motion to the gyrocenter and reduces the simulation from two-dimensional to one-dimensional, is valid for oblique wave-particle interaction. Multiple resonances appear for oblique propagation but not for parallel propagation. We calculate the possible range of resonances with the first-order resonance condition as a function of electron kinetic energy and equatorial pitch angle. To reveal the physical process and the efficiency of electron acceleration by multiple resonances, we assume a simple uniform wave model with constant amplitude and frequency in space and time. We perform test particle simulations with electrons starting at specific equatorial pitch angles and kinetic energies. The simulation results show that multiple resonances contribute to acceleration and pitch angle scattering of energetic electrons. Especially, we find that electrons with energies of a few hundred keV can be accelerated efficiently to a few MeV through the n = 0 Landau resonance.

Light and dark adaptation of visually perceived eye level controlled by visual pitch.

Science.gov (United States)

Matin, L; Li, W

1995-01-01

The pitch of a visual field systematically influences the elevation at which a monocularly viewing subject sets a target so as to appear at visually perceived eye level (VPEL). The deviation of the setting from true eye level average approximately 0.6 times the angle of pitch while viewing a fully illuminated complexly structured visual field and is only slightly less with one or two pitched-from-vertical lines in a dark field (Matin & Li, 1994a). The deviation of VPEL from baseline following 20 min of dark adaptation reaches its full value less than 1 min after the onset of illumination of the pitched visual field and decays exponentially in darkness following 5 min of exposure to visual pitch, either 30 degrees topbackward or 20 degrees topforward. The magnitude of the VPEL deviation measured with the dark-adapted right eye following left-eye exposure to pitch was 85% of the deviation that followed pitch exposure of the right eye itself. Time constants for VPEL decay to the dark baseline were the same for same-eye and cross-adaptation conditions and averaged about 4 min. The time constants for decay during dark adaptation were somewhat smaller, and the change during dark adaptation extended over a 16% smaller range following the viewing of the dim two-line pitched-from-vertical stimulus than following the viewing of the complex field. The temporal course of light and dark adaptation of VPEL is virtually identical to the course of light and dark adaptation of the scotopic luminance threshold following exposure to the same luminance. We suggest that, following rod stimulation along particular retinal orientations by portions of the pitched visual field, the storage of the adaptation process resides in the retinogeniculate system and is manifested in the focal system as a change in luminance threshold and in the ambient system as a change in VPEL. The linear model previously developed to account for VPEL, which was based on the interaction of influences from the

Effects of grit roughness and pitch oscillations on the LS(1)-0417MOD airfoil

Energy Technology Data Exchange (ETDEWEB)

Janiszewska, J.M.; Ramsay, R.R.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-01-01

Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculations of rotor performance and loads. The rotors also experience performance degradation caused by surface roughness. These surface irregularities are due to the accumulation of insect debris, ice, and/or the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. An LS(l)-0417MOD airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3{times}5 subsonic wind tunnel (3{times}5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, 1.25, and 1.5 million, while the angle of attack ranged from {minus}20{degrees} to +40{degrees}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.5 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used, {plus_minus} 5.5%{degrees} and {plus_minus} 10{degrees}, at mean angles of attack of 8{degrees}, 14{degrees}, and 20{degrees}. For purposes herein, any reference to unsteady conditions foil model was in pitch oscillation about the quarter chord.

Enhancing the stabilization of aircraft pitch motion control via intelligent and classical method

Science.gov (United States)

Lukman, H.; Munawwarah, S.; Azizan, A.; Yakub, F.; Zaki, S. A.; Rasid, Z. A.

2017-12-01

The pitching movement of an aircraft is very important to ensure passengers are intrinsically safe and the aircraft achieve its maximum stability. The equations governing the motion of an aircraft are a complex set of six nonlinear coupled differential equations. Under certain assumptions, it can be decoupled and linearized into longitudinal and lateral equations. Pitch control is a longitudinal problem and thus, only the longitudinal dynamics equations are involved in this system. It is a third order nonlinear system, which is linearized about the operating point. The system is also inherently unstable due to the presence of a free integrator. Because of this, a feedback controller is added in order to solve this problem and enhance the system performance. This study uses two approaches in designing controller: a conventional controller and an intelligent controller. The pitch control scheme consists of proportional, integral and derivatives (PID) for conventional controller and fuzzy logic control (FLC) for intelligent controller. Throughout the paper, the performance of the presented controllers are investigated and compared based on the common criteria of step response. Simulation results have been obtained and analysed by using Matlab and Simulink software. The study shows that FLC controller has higher ability to control and stabilize the aircraft's pitch angle as compared to PID controller.

Memory for pitch in congenital amusia: beyond a fine-grained pitch discrimination problem.

Science.gov (United States)

Williamson, Victoria Jane; Stewart, Lauren

2010-08-01

Congenital amusia is a disorder that affects the perception and production of music. While amusia has been associated with deficits in pitch discrimination, several reports suggest that memory deficits also play a role. The present study investigated short-term memory span for pitch-based and verbal information in 14 individuals with amusia and matched controls. Analogous adaptive-tracking procedures were used to generate tone and digit spans using stimuli that exceeded psychophysically measured pitch perception thresholds. Individuals with amusia had significantly smaller tone spans, whereas their digits spans were a similar size to those of controls. An automated operation span task was used to determine working memory capacity. Working memory deficits were seen in only a small subgroup of individuals with amusia. These findings support the existence of a pitch-specific component within short-term memory and suggest that congenital amusia is more than a disorder of fine-grained pitch discrimination.

Meta-analytic evidence for the non-modularity of pitch processing in congenital amusia.

Science.gov (United States)

Vuvan, Dominique T; Nunes-Silva, Marilia; Peretz, Isabelle

2015-08-01

A major theme driving research in congenital amusia is related to the modularity of this musical disorder, with two possible sources of the amusic pitch perception deficit. The first possibility is that the amusic deficit is due to a broad disorder of acoustic pitch processing that has the effect of disrupting downstream musical pitch processing, and the second is that amusia is specific to a musical pitch processing module. To interrogate these hypotheses, we performed a meta-analysis on two types of effect sizes contained within 42 studies in the amusia literature: the performance gap between amusics and controls on tasks of pitch discrimination, broadly defined, and the correlation between specifically acoustic pitch perception and musical pitch perception. To augment the correlation database, we also calculated this correlation using data from 106 participants tested by our own research group. We found strong evidence for the acoustic account of amusia. The magnitude of the performance gap was moderated by the size of pitch change, but not by whether the stimuli were composed of tones or speech. Furthermore, there was a significant correlation between an individual's acoustic and musical pitch perception. However, individual cases show a double dissociation between acoustic and musical processing, which suggests that although most amusic cases are probably explainable by an acoustic deficit, there is heterogeneity within the disorder. Finally, we found that tonal language fluency does not influence the performance gap between amusics and controls, and that there was no evidence that amusics fare worse with pitch direction tasks than pitch discrimination tasks. These results constitute a quantitative review of the current literature of congenital amusia, and suggest several new directions for research, including the experimental induction of amusic behaviour through transcranial magnetic stimulation (TMS) and the systematic exploration of the developmental

Performance of a single photon counting microstrip detector for strip pitches down to 10 μm

International Nuclear Information System (INIS)

Bergamaschi, A.; Broennimann, Ch.; Dinapoli, R.; Eikenberry, E.; Gozzo, F.; Henrich, B.; Kobas, M.; Kraft, P.; Patterson, B.; Schmitt, B.

2008-01-01

The MYTHEN detector is a one-dimensional microstrip detector with single photon counting readout optimized for time resolved powder diffraction experiments at the Swiss Light Source (SLS). The system has been successfully tested for many different synchrotron radiation applications including phase contrast and tomographic imaging, small angle scattering, diffraction and time resolved pump and probe experiments for X-ray energies down to 5 keV and counting rate up to 3 MHz. The frontend electronics is designed in order to be coupled to 50 μm pitch microstrip sensors but some interest in enhancing the spatial resolution is arising for imaging and powder diffraction experiments. A test structure with strip pitches in the range 10-50 μm has been tested and the gain and noise on the readout electronics have been measured for the different strip pitches, observing no large difference down to 25 μm. Moreover, the effect of the charge sharing between neighboring strips on the spatial resolution has been quantified by measuring the Point Spread Function (PSF) of the system for the different pitches

Performance of a single photon counting microstrip detector for strip pitches down to 10 μm

Science.gov (United States)

Bergamaschi, A.; Broennimann, Ch.; Dinapoli, R.; Eikenberry, E.; Gozzo, F.; Henrich, B.; Kobas, M.; Kraft, P.; Patterson, B.; Schmitt, B.

2008-06-01

The MYTHEN detector is a one-dimensional microstrip detector with single photon counting readout optimized for time resolved powder diffraction experiments at the Swiss Light Source (SLS). The system has been successfully tested for many different synchrotron radiation applications including phase contrast and tomographic imaging, small angle scattering, diffraction and time resolved pump and probe experiments for X-ray energies down to 5 keV and counting rate up to 3 MHz. The frontend electronics is designed in order to be coupled to 50 μm pitch microstrip sensors but some interest in enhancing the spatial resolution is arising for imaging and powder diffraction experiments. A test structure with strip pitches in the range 10-50 μm has been tested and the gain and noise on the readout electronics have been measured for the different strip pitches, observing no large difference down to 25 μm. Moreover, the effect of the charge sharing between neighboring strips on the spatial resolution has been quantified by measuring the Point Spread Function (PSF) of the system for the different pitches.

Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.

Science.gov (United States)

Keller, Robert A; Marshall, Nathan E; Guest, John-Michael; Okoroha, Kelechi R; Jung, Edward K; Moutzouros, Vasilios

2016-04-01

The number of Major League Baseball (MLB) pitchers requiring ulnar collateral ligament (UCL) reconstructions is increasing. Recent literature has attempted to correlate specific stresses placed on the throwing arm to risk for UCL injury, with limited results. Eighty-three MLB pitchers who underwent primary UCL reconstruction were evaluated. Pitching velocity and percent of pitch type thrown (fastball, curve ball, slider, and change-up) were evaluated 2 years before and after surgery. Data were compared with control pitchers matched for age, position, size, innings pitched, and experience. The evaluation of pitch velocity compared with matched controls found no differences in pre-UCL reconstruction pitch velocities for fastballs (91.5 vs. 91.2 miles per hour [mph], P = .69), curveballs (78.2 vs. 77.9 mph, P = .92), sliders (83.3 vs. 83.5 mph, P = .88), or change-ups (83.9 vs. 83.8 mph, P = .96). When the percentage of pitches thrown was evaluated, UCL reconstructed pitchers pitch significantly more fastballs than controls (46.7% vs. 39.4%, P = .035). This correlated to a 2% increase in risk for UCL injury for every 1% increase in fastballs thrown. Pitching more than 48% fastballs was a significant predictor of UCL injury, because pitchers over this threshold required reconstruction (P = .006). MLB pitchers requiring UCL reconstruction do not pitch at higher velocities than matched controls, and pitch velocity does not appear to be a risk factor for UCL reconstruction. However, MLB pitchers who pitch a high percentage of fastballs may be at increased risk for UCL injury because pitching a higher percent of fastballs appears to be a risk factor for UCL reconstruction. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Coal tar pitch. Interrelations between properties and utilization of coal tar pitch

Energy Technology Data Exchange (ETDEWEB)

Collin, G; Koehler, H [Ruetgerswerke A.G., Duisburg (Germany, F.R.)

1977-06-01

Coal tar pitch is won as a highly aromatic, thermoplastic residue by destillating coal tar. In this paper the structure as well as the chemical and physical data of this pitch are introduced. In addition to this the actual as well as possible applications are indicated. For example, the pitch can be used for the production of binders, e.g. for electrodes and road construction as well as in combination with plastics for the production of insulating material and corrosion protection material.

Pitch perception prior to cortical maturation

Science.gov (United States)

Lau, Bonnie K.

Pitch perception plays an important role in many complex auditory tasks including speech perception, music perception, and sound source segregation. Because of the protracted and extensive development of the human auditory cortex, pitch perception might be expected to mature, at least over the first few months of life. This dissertation investigates complex pitch perception in 3-month-olds, 7-month-olds and adults -- time points when the organization of the auditory pathway is distinctly different. Using an observer-based psychophysical procedure, a series of four studies were conducted to determine whether infants (1) discriminate the pitch of harmonic complex tones, (2) discriminate the pitch of unresolved harmonics, (3) discriminate the pitch of missing fundamental melodies, and (4) have comparable sensitivity to pitch and spectral changes as adult listeners. The stimuli used in these studies were harmonic complex tones, with energy missing at the fundamental frequency. Infants at both three and seven months of age discriminated the pitch of missing fundamental complexes composed of resolved and unresolved harmonics as well as missing fundamental melodies, demonstrating perception of complex pitch by three months of age. More surprisingly, infants in both age groups had lower pitch and spectral discrimination thresholds than adult listeners. Furthermore, no differences in performance on any of the tasks presented were observed between infants at three and seven months of age. These results suggest that subcortical processing is not only sufficient to support pitch perception prior to cortical maturation, but provides adult-like sensitivity to pitch by three months.

Thermal electron acceleration by electric field spikes in the outer radiation belt: generation of field-aligned pitch angle distributions

Science.gov (United States)

Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.

2015-12-01

Van Allen Probes observations in the outer radiation belt have demonstrated an abundance non-linear electrostatic stucture called Time Domain Structures (TDS). One of the type of TDS is electrostatic electron-acoustic double layers (DL). Observed DLs are frequently accompanied by field-aligned (bi-directional) pitch angle distributions (PAD) of electrons with energies from hundred eVs up to several keV (rarely up to tens of keV). We perform numerical simulations of the DL interaction with thermal electrons making use of the test particle approach. DL parameters assumed in the simulations are adopted from observations. We show that DLs accelerate thermal electrons parallel to the magnetic field via the electrostatic Fermi mechanism, i.e. due to reflections from DL potential humps. Due to this interaction some fraction of electrons is scattered into the loss cone. The electron energy gain is larger for larger DL scalar potential amplitudes and higher propagation velocities. In addition to the Fermi mechanism electrons can be trapped by DLs in their generation region and accelerated due to transport to higher latitudes. Both mechanisms result in formation of field-aligned PADs for electrons with energies comparable to those found in observations. The Fermi mechanism provides field-aligned PADs for <1 keV electrons, while the trapping mechanism extends field-aligned PADs to higher energy electrons.

Using Order Tracking Analysis Method to Detect the Angle Faults of Blades on Wind Turbine

DEFF Research Database (Denmark)

Li, Pengfei; Hu, Weihao; Liu, Juncheng

2016-01-01

The angle faults of blades on wind turbines are usually included in the set angle fault and the pitch angle fault. They are occupied with a high proportion in all wind turbine faults. Compare with the traditional fault detection methods, using order tracking analysis method to detect angle faults....... By analyzing and reconstructing the fault signals, it is easy to detect the fault characteristic frequency and see the characteristic frequencies of angle faults depend on the shaft rotating frequency, which is known as the 1P frequency and 3P frequency distinctly....

Switching between pitch surfaces

DEFF Research Database (Denmark)

Rago, Vincenzo; Silva, João R; Brito, João

2018-01-01

Soccer training and completion is conventionally practiced on natural grass (NG) or artificial turf (AT). Recently, AT pitches for training / competition, and of unstable surfaces for injury prevention training has increased. Therefore, soccer players are frequently exposed to variations in pitch...... surface during either training or competition. These ground changes may impact physical and physiological responses, adaptations as well as the injury. The aim of this review was to summarize the acute physical and physiological responses, chronic adaptations, and injury risk associated with exercising...... on different pitch surfaces in soccer. Eligible studies were published in English, had pitch surface as an independent variable, and had physical, physiological or epidemiological information as outcome variables. Specific data extracted from the articles included the training response, training adaptations...

The role of the auditory brainstem in processing musically-relevant pitch

Directory of Open Access Journals (Sweden)

Gavin M. Bidelman

2013-05-01

Full Text Available Neuroimaging work has shed light on the cerebral architecture involved in processing the melodic and harmonic aspects of music. Here, recent evidence is reviewed illustrating that subcortical auditory structures contribute to the early formation and processing of musically-relevant pitch. Electrophysiological recordings from the human brainstem and population responses from the auditory nerve reveal that nascent features of tonal music (e.g., consonance/dissonance, pitch salience, harmonic sonority are evident at early, subcortical levels of the auditory pathway. The salience and harmonicity of brainstem activity is strongly correlated with listeners’ perceptual preferences and perceived consonance for the tonal relationships of music. Moreover, the hierarchical ordering of pitch intervals/chords described by the Western music practice and their perceptual consonance is well-predicted by the salience with which pitch combinations are encoded in subcortical auditory structures. While the neural correlates of consonance can be tuned and exaggerated with musical training, they persist even in the absence of musicianship or long-term enculturation. As such, it is posited that the structural foundations of musical pitch might result from innate processing performed by the central auditory system. A neurobiological predisposition for consonant, pleasant sounding pitch relationships may be one reason why these pitch combinations have been favored by composers and listeners for centuries. It is suggested that important perceptual dimensions of music emerge well before the auditory signal reaches cerebral cortex and prior to attentional engagement. While cortical mechanisms are no doubt critical to the perception, production, and enjoyment of music, the contribution of subcortical structures implicates a more integrated, hierarchically organized network underlying music processing within the brain.

Musical Activity Tunes Up Absolute Pitch Ability

DEFF Research Database (Denmark)

Dohn, Anders; Garza-Villarreal, Eduardo A.; Ribe, Lars Riisgaard

2014-01-01

Absolute pitch (AP) is the ability to identify or produce pitches of musical tones without an external reference. Active AP (i.e., pitch production or pitch adjustment) and passive AP (i.e., pitch identification) are considered to not necessarily coincide, although no study has properly compared...

DAC with LQR Control Design for Pitch Regulated Variable Speed Wind Turbine

DEFF Research Database (Denmark)

Imran, Raja Muhammad; Hussain, Dil Muhammad Akbar; Soltani, Mohsen

2014-01-01

Disturbance Accommodation Control (DAC) is used to model and simulate a system with known disturbance waveform. This paper presents a control scheme to mitigate the effect of disturbances by using collective pitch control for the aboverated wind speed (Region III) for a variable speed wind turbine....... We have used Linear Quadratic Regulator (LQR) to obtain full state feedback gain, disturbance feedback gain is calculated independently and then estimator gain is achieved by poleplacement technique in the DAC augmented plant model. The reduced order model (two-mass model) of wind turbine is used...... and 5MW National Renewable Energy Laboratory (NREL) wind turbine is used in this research. We have shown comparison of results relating to pitch angle, drive train torsion and generator speed obtained by a PID controller and DAC. Simulations are performed in MATLAB/Simulink. The results are compared...

High-pitch metal-on-glass technology for pad pitch adaptation between detectors and readout electronics

CERN Document Server

Ullán, Miguel; Campabadal, Francesca; Fleta, Celeste; Garcia, Carmen; Gonzalez, Francisco; Bernabeu, Jose

2004-01-01

Modern high-energy physics and astrophysics strip detectors have increased channel density to levels at which their connection with readout electronics has become very complex due to high pad pitch. Also, direct wire bonding is prevented by the fact that typically detector's pad pitch and electronics' pad pitch do not match. A high- pitch metal-on-glass technology is presented, that allows pad pitch adaptation between detectors and readout electronics. It consists of high-density metal lines on top of an insulating glass substrate. A photoresist layer is deposited covering the metal tracks for passivation and protection The technology is tested for conductivity, bondability, bonding pull force, peel off, and radiation hardness, and it is an established technology in the clean room of the CNM Institute in Barcelona. This technology has been chosen by the ATLAS Collaboration for the pad pitch adapters (PPA) of the SCT Endcap Modules, by a Compton camera project, and by other HEP groups for interconnection betwe...

A nonmusical paradigm for identifying absolute pitch possessors

Science.gov (United States)

Ross, David A.; Olson, Ingrid R.; Marks, Lawrence E.; Gore, John C.

2004-09-01

The ability to identify and reproduce sounds of specific frequencies is remarkable and uncommon. The etiology and defining characteristics of this skill, absolute pitch (AP), have been very controversial. One theory suggests that AP requires a specific type of early musical training and that the ability to encode and remember tones depends on these learned musical associations. An alternate theory argues that AP may be strongly dependent on hereditary factors and relatively independent of musical experience. To date, it has been difficult to test these hypotheses because all previous paradigms for identifying AP have required subjects to employ knowledge of musical nomenclature. As such, these tests are insensitive to the possibility of discovering AP in either nonmusicians or musicians of non-Western training. Based on previous literature in pitch memory, a paradigm is presented that is intended to distinguish between AP possessors and nonpossessors independent of the subjects' musical experience. The efficacy of this method is then tested with 20 classically defined AP possessors and 22 nonpossessors. Data from these groups strongly support the validity of the paradigm. The use of a nonmusical paradigm to identify AP may facilitate research into many aspects of this phenomenon.

The influence of music-elicited emotions and relative pitch on absolute pitch memory for familiar melodies.

Science.gov (United States)

Jakubowski, Kelly; Müllensiefen, Daniel

2013-01-01

Levitin's findings that nonmusicians could produce from memory the absolute pitches of self-selected pop songs have been widely cited in the music psychology literature. These findings suggest that latent absolute pitch (AP) memory may be a more widespread trait within the population than traditional AP labelling ability. However, it has been left unclear what factors may facilitate absolute pitch retention for familiar pieces of music. The aim of the present paper was to investigate factors that may contribute to latent AP memory using Levitin's sung production paradigm for AP memory and comparing results to the outcomes of a pitch labelling task, a relative pitch memory test, measures of music-induced emotions, and various measures of participants' musical backgrounds. Our results suggest that relative pitch memory and the quality and degree of music-elicited emotions impact on latent AP memory.

Disorders of pitch production in tone deafness

Directory of Open Access Journals (Sweden)

Simone eDalla Bella

2011-07-01

Full Text Available Singing is as natural as speaking for the majority of people. Yet some individuals (i.e., 10-15% are inaccurate singers, typically performing or imitating pitches and melodies inaccurately. This condition, commonly referred to as tone deafness, has been observed both in the presence and absence of deficient pitch perception. In this article we review the existing literature concerning normal singing, poor-pitch singing, and, briefly, the sources of this condition. Considering that pitch plays a prominent role in the structure of both music and speech we also focus on the possibility that pitch production (or imitation is similarly impaired in poor-pitch singers. Preliminary evidence from our laboratory on poor-pitch singing suggests that pitch imitation may be selectively inaccurate in the music domain without being affected in speech. This finding points to separability of mechanisms subserving pitch production in music and language.

Tone language fluency impairs pitch discrimination

Directory of Open Access Journals (Sweden)

Isabelle ePeretz

2011-07-01

Full Text Available Here we present evidence that native speakers of a tone language, in which pitch contributes to word meaning, are impaired in the discrimination of falling pitches in tone sequences, as compared to speakers of a non-tone language. Both groups were presented with monotonic and isochronous sequences of five tones (i.e., constant pitch and intertone interval. They were required to detect when the fourth tone was displaced in pitch or time. While speakers of a tone language performed more poorly in the detection of downward pitch changes, they did not differ from non-tone language speakers in their perception of upward pitch changes or in their perception of subtle time changes. Moreover, this impairment cannot be attributed to low musical aptitude since the impairment remains unchanged when individual differences in musical pitch-based processing is taken into account. Thus, the impairment appears highly specific and may reflect the influence of statistical regularities of tone languages.

Operation Design of Wind Turbines in Strong Wind Conditions

DEFF Research Database (Denmark)

Shen, Wen Zhong; Montes, Melissa Barroso; Odgaard, Peter Fogh

2012-01-01

and variable speed pitch regulated wind turbines. The variable speed design is more suitable for wind turbines to run at very high wind speeds which can help the turbine braking system to stop the turbine at the new "cut-out" wind speed. Reference power, rotational speed and pitch angle have been designed...... optimally. In order to reduce the possible increased loading, fatigue due to the wind gusts, control strategies have been considered for both constant sped and variable speed pitch regulated wind turbines. The control study shows that the designed controllers can reduce the standard deviations efficiently......In order to reduce the impact on the electrical grid from the shutdown of MW wind turbines at wind speeds higher than the cut-out wind speed of 25 m/s, we propose in this paper to run the turbines at high wind speeds up to 40 m/s. Two different operation designs are made for both constant speed...

Aerodynamic tricks for pitching oscillation and visual stabilization in a hovering bird

Science.gov (United States)

Su, Jian-Yuan; Ting, Shang-Chieh; Yang, Jing-Tang

2010-11-01

We experimentally investigate how small birds attain a stabilized vision and body posture during hovering. Wing-beats of finches and passerines executing asymmetrical hovering provide lift merely during the downstroke. The downstroke lift is significantly greater than the bird weight, thereby causing a pitch-up swing of the bird body. A hovering bird skillfully and unceasingly tunes the position and orientation of lift force to stabilize its vision, so that the eye displacement is approximately one-tenth less than the tail, causing an illusion that the bird body is rotating about the eye. The hovering birds also spread and fold periodically their tail with an evident phase relationship with respect to the beating wings. We found that hovering birds use their tail to intercept the strong downward air-flow induced by the downstroking wings, and sophisticatedly spread their tail upon the arrival of the downward air-flow, rendering a pitch-up moment that effectively counteracts the pitch-down body rotation. Hence during hovering the bird essentially undergoes a dynamically-stable pitching oscillation, and concurrently attains a stabilized vision.

Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

Directory of Open Access Journals (Sweden)

J. J. Lee

2012-11-01

Full Text Available Electron microburst energy spectra in the range of 170 keV to 360 keV have been measured using two solid-state detectors onboard the low-altitude (680 km, polar-orbiting Korean STSAT-1 (Science and Technology SATellite-1. Applying a unique capability of the spacecraft attitude control system, microburst energy spectra have been accurately resolved into two components: perpendicular to and parallel to the geomagnetic field direction. The former measures trapped electrons and the latter those electrons with pitch angles in the loss cone and precipitating into atmosphere. It is found that the perpendicular component energy spectra are harder than the parallel component and the loss cone is not completely filled by the electrons in the energy range of 170 keV to 360 keV. These results have been modeled assuming a wave-particle cyclotron resonance mechanism, where higher energy electrons travelling within a magnetic flux tube interact with whistler mode waves at higher latitudes (lower altitudes. Our results suggest that because higher energy (relativistic microbursts do not fill the loss cone completely, only a small portion of electrons is able to reach low altitude (~100 km atmosphere. Thus assuming that low energy microbursts and relativistic microbursts are created by cyclotron resonance with chorus elements (but at different locations, the low energy portion of the microburst spectrum will dominate at low altitudes. This explains why relativistic microbursts have not been observed by balloon experiments, which typically float at altitudes of ~30 km and measure only X-ray flux produced by collisions between neutral atmospheric particles and precipitating electrons.

Attending to pitch information inhibits processing of pitch information: the curious case of amusia.

Science.gov (United States)

Zendel, Benjamin Rich; Lagrois, Marie-Élaine; Robitaille, Nicolas; Peretz, Isabelle

2015-03-04

In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individuals, known as amusics, the processing of tonality is disordered, which results in severe musical deficits. It has been shown that the tonal rules of music are neurally encoded, but not consciously available in amusics. Previous neurophysiological studies have not explicitly controlled the level of attention in tasks where participants ignored the tonal structure of the stimuli. Here, we test whether access to tonal knowledge can be demonstrated in congenital amusia when attention is controlled. Electric brain responses were recorded while asking participants to detect an individually adjusted near-threshold click in a melody. In half the melodies, a note was inserted that violated the tonal rules of music. In a second task, participants were presented with the same melodies but were required to detect the tonal deviation. Both tasks required sustained attention, thus conscious access to the rules of tonality was manipulated. In the click-detection task, the pitch deviants evoked an early right anterior negativity (ERAN) in both groups. In the pitch-detection task, the pitch deviants evoked an ERAN and P600 in controls but not in amusics. These results indicate that pitch regularities are represented in the cortex of amusics, but are not consciously available. Moreover, performing a pitch-judgment task eliminated the ERAN in amusics, suggesting that attending to pitch information interferes with perception of pitch. We propose that an impaired top-down frontotemporal projection is responsible for this disorder. Copyright © 2015 the authors 0270-6474/15/353815-10$15.00/0.

Effect of Channel Orientation and Rib Pitch-to-Height Ratio on Pressure Drop in a Rotating Square Channel with Ribs on Two Opposite Surfaces

Directory of Open Access Journals (Sweden)

Prabhu S. V.

2005-01-01

Full Text Available The effect of channel orientation and rib pitch-to-height ratio on the pressure drop distribution in a rib-roughened channel is an important issue in turbine blade cooling. The present investigation is a study of the overall pressure drop distribution in a square cross-sectioned channel, with rib turbulators, rotating about an axis normal to the free stream. The ribs are configured in a symmetric arrangement on two opposite surfaces with a rib angle of 90 ∘ to the mainstream flow. The study has been conducted for three Reynolds numbers, namely, 13 000, 17 000, and 22 000 with the rotation number varying from 0– 0.38 . Experiments have been carried out for various rib pitch-to-height ratios ( P/e with a constant rib height-to-hydraulic diameter ratio ( e/D of 0.1 . The test section in which the ribs are placed on the leading and trailing surfaces is considered as the base case ( orientation angle= 0 ∘ , Coriolis force vector normal to the ribbed surfaces. The channel is turned about its axis in steps of 15 ∘ to vary the orientation angle from 0 ∘ to 90 ∘ . The overall pressure drop does not change considerably under conditions of rotation for the base case. However, for the other cases tested, it is observed that the overall pressure drop increases with an increase in the rotation number for a given orientation angle and also increases with an increase in the orientation angle for a given rotation number. This change is attributed to the variation in the separation zone downstream of the ribs due to the presence of the Coriolis force—local pressure drop data is presented which supports this idea. At an orientation angle of 90 ∘ (ribs on the top and bottom surfaces, Coriolis force vector normal to the smooth surfaces, the overall pressure drop is observed to be maximum during rotation. The overall pressure drop for a case with a rib pitch-to-height ratio of 5 on both surfaces is found to be the highest

Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG

DEFF Research Database (Denmark)

Zhang, Yunqian; Chen, Zhe; Hu, Weihao

2014-01-01

generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power...... and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind......Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction...

High coking value pitch

Science.gov (United States)

Miller, Douglas J.; Chang, Ching-Feng; Lewis, Irwin C.; Lewis, Richard T.

2014-06-10

A high coking value pitch prepared from coal tar distillate and has a low softening point and a high carbon value while containing substantially no quinoline insolubles is disclosed. The pitch can be used as an impregnant or binder for producing carbon and graphite articles.

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

Energy Technology Data Exchange (ETDEWEB)

Pace, D. C., E-mail: pacedc@fusion.gat.com; Fisher, R. K.; Van Zeeland, M. A. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Pipes, R. [Department of Physics, University of Hawaii, Hilo, Hawaii 96720-4091 (United States)

2014-11-15

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector.

Science.gov (United States)

Pace, D C; Pipes, R; Fisher, R K; Van Zeeland, M A

2014-11-01

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Pitch-Responsive Cortical Regions in Congenital Amusia.

Science.gov (United States)

Norman-Haignere, Sam V; Albouy, Philippe; Caclin, Anne; McDermott, Josh H; Kanwisher, Nancy G; Tillmann, Barbara

2016-03-09

Congenital amusia is a lifelong deficit in music perception thought to reflect an underlying impairment in the perception and memory of pitch. The neural basis of amusic impairments is actively debated. Some prior studies have suggested that amusia stems from impaired connectivity between auditory and frontal cortex. However, it remains possible that impairments in pitch coding within auditory cortex also contribute to the disorder, in part because prior studies have not measured responses from the cortical regions most implicated in pitch perception in normal individuals. We addressed this question by measuring fMRI responses in 11 subjects with amusia and 11 age- and education-matched controls to a stimulus contrast that reliably identifies pitch-responsive regions in normal individuals: harmonic tones versus frequency-matched noise. Our findings demonstrate that amusic individuals with a substantial pitch perception deficit exhibit clusters of pitch-responsive voxels that are comparable in extent, selectivity, and anatomical location to those of control participants. We discuss possible explanations for why amusics might be impaired at perceiving pitch relations despite exhibiting normal fMRI responses to pitch in their auditory cortex: (1) individual neurons within the pitch-responsive region might exhibit abnormal tuning or temporal coding not detectable with fMRI, (2) anatomical tracts that link pitch-responsive regions to other brain areas (e.g., frontal cortex) might be altered, and (3) cortical regions outside of pitch-responsive cortex might be abnormal. The ability to identify pitch-responsive regions in individual amusic subjects will make it possible to ask more precise questions about their role in amusia in future work. Copyright © 2016 the authors 0270-6474/16/362986-09$15.00/0.

VLSI implementation of an AMDF pitch detector

OpenAIRE

Smith, Tony; Gittel, Falko; Schwarzbacher, Andreas; Hilt, E.; Timoney, Joseph

2003-01-01

Pitch detectors are used in a variety of speech processing applications such as speech recognition systems where the pitch of the speaker is used as one parameter for identification purposes. Furthermore, pitch detectors are also sued with adaptive filters to achieve high quality adaptive noise cancellation of speech signals. In voice conversion systems, pitch detection is an essential step since the pitch of the modified signal is altered to model the target voice. This paper describes a ...

Measurement of pitch in speech : an implementation of Goldstein's theory of pitch perception

NARCIS (Netherlands)

Duifhuis, H.; Willems, L.F.; Sluyter, R.J.

1982-01-01

Recent developments in hearing theory have resulted in the rather general acceptance of the idea that the perception of pitch of complex sounds is the result of the psychological pattern recognition process. The pitch is supposedly mediated by the fundamental of the harmonic spectrum which fits the

Disorders of pitch production in tone deafness.

Science.gov (United States)

Bella, Simone Dalla; Berkowska, Magdalena; Sowiński, Jakub

2011-01-01

Singing is as natural as speaking for the majority of people. Yet some individuals (i.e., 10-15%) are poor singers, typically performing or imitating pitches and melodies inaccurately. This condition, commonly referred to as "tone deafness," has been observed both in the presence and absence of deficient pitch perception. In this article we review the existing literature concerning normal singing, poor-pitch singing, and, briefly, the sources of this condition. Considering that pitch plays a prominent role in the structure of both music and speech we also focus on the possibility that speech production (or imitation) is similarly impaired in poor-pitch singers. Preliminary evidence from our laboratory suggests that pitch imitation may be selectively inaccurate in the music domain without being affected in speech. This finding points to separability of mechanisms subserving pitch production in music and language.

Pitch memory and exposure effects.

OpenAIRE

Ben-Haim, Moshe Shay; Eitan, Zohar; Chajut, Eran

2014-01-01

Recent studies indicate that the ability to represent absolute pitch values in long-term memory (LTM), long believed to be the possession of a small minority of trained musicians endowed with "absolute pitch" (AP), is in fact shared to some extent by a considerable proportion of the population. The current study examined whether this newly-discovered ability affects aspects of music and auditory cognition, particularly pitch learning and evaluation. Our starting points are two well establishe...

Disorders of Pitch Production in Tone Deafness

Science.gov (United States)

Bella, Simone Dalla; Berkowska, Magdalena; Sowiński, Jakub

2011-01-01

Singing is as natural as speaking for the majority of people. Yet some individuals (i.e., 10–15%) are poor singers, typically performing or imitating pitches and melodies inaccurately. This condition, commonly referred to as “tone deafness,” has been observed both in the presence and absence of deficient pitch perception. In this article we review the existing literature concerning normal singing, poor-pitch singing, and, briefly, the sources of this condition. Considering that pitch plays a prominent role in the structure of both music and speech we also focus on the possibility that speech production (or imitation) is similarly impaired in poor-pitch singers. Preliminary evidence from our laboratory suggests that pitch imitation may be selectively inaccurate in the music domain without being affected in speech. This finding points to separability of mechanisms subserving pitch production in music and language. PMID:21811479

Thermosetting behavior of pitch-resin from heavy residue

Energy Technology Data Exchange (ETDEWEB)

Qingfang, Z.; Yansheng, G.; Baohua, H.; Yuzhen, Z. [China Univ. of Petroleum, Dongying, Shandong (China). State Key LAboratory of Heavy Oil Processing, Heavy Oil Research Inst.

2006-07-01

Thermosetting resins are widely employed as a basic matrix for c/c composites in carbon materials production. A new type of synthesized thermosetting resin is called pitch resin. Pitch resin is a cheaper resin and possesses a potential opportunity for future use. However, the thermosetting behavior of pitch resin is not very clear. The hardening process and conditions for thermosetting are very important for future use of pitch resin. B-stage pitch resin is a soluble and meltable inter-media condensed polymer, which is not fully reacted and is of a low molecular weight. The insoluble and unmelted pitch resin can only be obtained from synthesized B-stage resin after a hardening stage. This paper presented an experiment that synthesized B-stage pitch resin with a link agent (PXG) under catalyst action from fluid catalytic cracking (FCC) of the slurry's aromatic enriched component (FCCDF). The paper discussed the experiment, including the synthesis of pitch resin and thermosetting of pitch resin. Two kinds of thermosetting procedures were used in the study called one-step thermosetting and two-step thermosetting. It was concluded that the B-stage pitch resin could be hardened after a thermosetting procedure by heat treatment. The thermosetting pitch resin from 2-step thermosetting possesses was found to have better thermal resistant properties than that of the 1-step thermosetting pitch resin. 13 refs., 2 tabs., 6 figs.

Norwegian Pitched Roof Defects

Directory of Open Access Journals (Sweden)

Lars Gullbrekken

2016-06-01

Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

Ideomotor effects of pitch on continuation tapping.

Science.gov (United States)

Ammirante, Paolo; Thompson, William F; Russo, Frank A

2011-02-01

The ideomotor principle predicts that perception will modulate action where overlap exists between perceptual and motor representations of action. This effect is demonstrated with auditory stimuli. Previous perceptual evidence suggests that pitch contour and pitch distance in tone sequences may elicit tonal motion effects consistent with listeners' implicit awareness of the lawful dynamics of locomotive bodies. To examine modulating effects of perception on action, participants in a continuation tapping task produced a steady tempo. Auditory tones were triggered by each tap. Pitch contour randomly and persistently varied within trials. Pitch distance between successive tones varied between trials. Although participants were instructed to ignore them, tones systematically affected finger dynamics and timing. Where pitch contour implied positive acceleration, the following tap and the intertap interval (ITI) that it completed were faster. Where pitch contour implied negative acceleration, the following tap and the ITI that it completed were slower. Tempo was faster with greater pitch distance. Musical training did not predict the magnitude of these effects. There were no generalized effects on timing variability. Pitch contour findings demonstrate how tonal motion may elicit the spontaneous production of accents found in expressive music performance.

Measurement of cluster elongation and charge in a pixel detector of 10~$\\mu$m pitch at sub-GeV energies

OpenAIRE

Adamus, M.; Ciborowski, J.; Maczewski, L.; Luzniak, P.

2011-01-01

We present measurements of elongation and cluster charge using MIMOSA-18 MAPS pixel matrix with 10 $\\mu$m pixel pitch, using electron test beams of energies ranging from 15 to 500 MeV. We observe energy dependence of cluster charge and elongation for large incident angles.

Cross-Cultural Perspectives on Pitch Memory

Science.gov (United States)

Trehub, Sandra E.; Schellenberg, E. Glenn; Nakata, Takayuki

2008-01-01

We examined effects of age and culture on children's memory for the pitch level of familiar music. Canadian 9- and 10-year-olds distinguished the original pitch level of familiar television theme songs from foils that were pitch-shifted by one semitone, whereas 5- to 8-year-olds failed to do so (Experiment 1). In contrast, Japanese 5- and…

SU-F-P-31: Dosimetric Effects of Roll and Pitch Corrections Using Robotic Table

Energy Technology Data Exchange (ETDEWEB)

Mamalui, M; Su, Z; Flampouri, S; Li, Z [University of Florida Proton Therapy Institute, Jacksonville, FL (United States)

2016-06-15

Purpose: To quantify the dosimetric effect of roll and pitch corrections being performed by two types of robotic tables available at our institution: BrainLabTM 5DOF robotic table installed at VERO (BrainLab&MHI) dedicated SBRT linear accelerator and 6DOF robotic couch by IBA Proton Therapy with QFixTM couch top. Methods: Planning study used a thorax phantom (CIRSTM), scanned at 4DCT protocol; targets (IGTV, PTV) were determined according to the institutional lung site-specific standards. 12 CT sets were generated with Pitch and Roll angles ranging from −4 to +4 degrees each. 2 table tops were placed onto the scans according to the modality-specific patient treatment workflows. The pitched/rolled CT sets were fused to the original CT scan and the verification treatment plans were generated (12 photon SBRT plans and 12 proton conventional fractionation lung plans). Then the CT sets were fused again to simulate the effect of patient roll/pitch corrections by the robotic table. DVH sets were evaluated for all cases. Results: The effect of not correcting the phantom position for roll/pitch in photon SBRT cases was reducing the target coverage by 2% as maximum; correcting the positional errors by robotic table varied the target coverage within 0.7%. in case of proton treatment, not correcting the phantom position led to the coverage loss up to 4%, applying the corrections using robotic table reduced the coverage variation to less than 2% for PTV and within 1% for IGTV. Conclusion: correcting the patient position by using robotic tables is highly preferable, despite the small dosimetric changes introduced by the devices.

SU-F-P-31: Dosimetric Effects of Roll and Pitch Corrections Using Robotic Table

International Nuclear Information System (INIS)

Mamalui, M; Su, Z; Flampouri, S; Li, Z

2016-01-01

Purpose: To quantify the dosimetric effect of roll and pitch corrections being performed by two types of robotic tables available at our institution: BrainLabTM 5DOF robotic table installed at VERO (BrainLab&MHI) dedicated SBRT linear accelerator and 6DOF robotic couch by IBA Proton Therapy with QFixTM couch top. Methods: Planning study used a thorax phantom (CIRSTM), scanned at 4DCT protocol; targets (IGTV, PTV) were determined according to the institutional lung site-specific standards. 12 CT sets were generated with Pitch and Roll angles ranging from −4 to +4 degrees each. 2 table tops were placed onto the scans according to the modality-specific patient treatment workflows. The pitched/rolled CT sets were fused to the original CT scan and the verification treatment plans were generated (12 photon SBRT plans and 12 proton conventional fractionation lung plans). Then the CT sets were fused again to simulate the effect of patient roll/pitch corrections by the robotic table. DVH sets were evaluated for all cases. Results: The effect of not correcting the phantom position for roll/pitch in photon SBRT cases was reducing the target coverage by 2% as maximum; correcting the positional errors by robotic table varied the target coverage within 0.7%. in case of proton treatment, not correcting the phantom position led to the coverage loss up to 4%, applying the corrections using robotic table reduced the coverage variation to less than 2% for PTV and within 1% for IGTV. Conclusion: correcting the patient position by using robotic tables is highly preferable, despite the small dosimetric changes introduced by the devices.

Effect of Aspect Ratio, Channel Orientation, Rib Pitch-to-Height Ratio, and Number of Ribbed Walls on Pressure Drop Characteristics in a Rotating Channel with Detached Ribs

Directory of Open Access Journals (Sweden)

K. Arun

2007-01-01

Full Text Available The present work involves experimental investigation of the effects of aspect ratio, channel orientation angle, rib pitch-to-height ratio (P/e, and number of ribbed walls on friction factor in orthogonally rotating channel with detached ribs. The ribs are separated from the base wall to provide a small region of flow between the base wall and the ribs. Experiments have been conducted at Reynolds number ranging from 10000–17000 with rotation numbers varying from 0–0.38. Pitch-to-rib height ratios (P/e of 5 and 10 at constant rib height-to-hydraulic diameter ratio (e/D of 0.1 and a clearance ratio (C/e of 0.38 are considered. The rib angle of attack with respect to mainstream flow is 90∘. The channel orientation at which the ribbed wall becomes trailing surface (pressure side on which the Coriolis force acts is considered as the 0∘ orientation angle. For one-wall ribbed case, channel is oriented from 0∘ to 180∘ about its axis in steps of 30∘ to change the orientation angle. For two-wall ribbed case, the orientation angle is changed from 0∘ to 90∘ in steps of 30∘. Friction factors for the detached ribbed channels are compared with the corresponding attached ribbed channel. It is found that in one-wall detached ribbed channel, increase in the friction factor ratio with the orientation angle is lower for rectangular channel compared to that of square channel for both the pitch-to-rib height ratios of 5 and 10 at a given Reynolds number and rotation number. Friction factor ratios of two-wall detached ribbed rectangular channel are comparable with corresponding two-wall detached ribbed square channel both under stationary and rotating conditions.

A Neuronal Network Model for Pitch Selectivity and Representation.

Science.gov (United States)

Huang, Chengcheng; Rinzel, John

2016-01-01

Pitch is a perceptual correlate of periodicity. Sounds with distinct spectra can elicit the same pitch. Despite the importance of pitch perception, understanding the cellular mechanism of pitch perception is still a major challenge and a mechanistic model of pitch is lacking. A multi-stage neuronal network model is developed for pitch frequency estimation using biophysically-based, high-resolution coincidence detector neurons. The neuronal units respond only to highly coincident input among convergent auditory nerve fibers across frequency channels. Their selectivity for only very fast rising slopes of convergent input enables these slope-detectors to distinguish the most prominent coincidences in multi-peaked input time courses. Pitch can then be estimated from the first-order interspike intervals of the slope-detectors. The regular firing pattern of the slope-detector neurons are similar for sounds sharing the same pitch despite the distinct timbres. The decoded pitch strengths also correlate well with the salience of pitch perception as reported by human listeners. Therefore, our model can serve as a neural representation for pitch. Our model performs successfully in estimating the pitch of missing fundamental complexes and reproducing the pitch variation with respect to the frequency shift of inharmonic complexes. It also accounts for the phase sensitivity of pitch perception in the cases of Schroeder phase, alternating phase and random phase relationships. Moreover, our model can also be applied to stochastic sound stimuli, iterated-ripple-noise, and account for their multiple pitch perceptions.

Apparent Contact Angle and Contact Angle Hysteresis on Liquid Infused Surfaces

OpenAIRE

Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

2016-01-01

We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...

Pitch Based Sound Classification

DEFF Research Database (Denmark)

Nielsen, Andreas Brinch; Hansen, Lars Kai; Kjems, U

2006-01-01

A sound classification model is presented that can classify signals into music, noise and speech. The model extracts the pitch of the signal using the harmonic product spectrum. Based on the pitch estimate and a pitch error measure, features are created and used in a probabilistic model with soft......-max output function. Both linear and quadratic inputs are used. The model is trained on 2 hours of sound and tested on publicly available data. A test classification error below 0.05 with 1 s classification windows is achieved. Further more it is shown that linear input performs as well as a quadratic......, and that even though classification gets marginally better, not much is achieved by increasing the window size beyond 1 s....

[Factors influencing the pitch and loudness of tinnitus].

Science.gov (United States)

Ueda, S; Asoh, S; Watanabe, Y

1992-11-01

Pitch match and loudness balance tests were given to 397 cases with tinnitus. The factors which influenced tinnitus pitch and loudness were analyzed statistically from the clinical point of view. The results obtained were as follows: 1) Onomatopoeia of tinnitus, either [Keeeen] or [Jeeeen], were observed in a majority of cases. 2) Significantly sharp sounding onomatopoeia such as [Keeeen] or [Meeeen] had high pitches, over 4kHz, and dull sounds like [Gooooh] or [Buuuun] had low pitches, below 500Hz. 3) Acute stage tinnitus, within one month of onset, had a significantly depressed pitch and walked loudness, above 6dB. 4) The pitches observed in cases with Meniere's disease and chronic otitis media were distributed evenly from low frequencies to high. In other cases, especially presbyacusis and noise deafness, high pitch tinnitus (above 4kHz) was frequently noted. The loudness of tinnitus without hearing loss was significantly greater than in other diseases. 5) As a rule the more deteriorated the hearing level was, the lower the frequency of the pitch, and the smaller the loudness in tinnitus. 6) A high pitch of tinnitus nearly corresponded with hearing type, that is, the pitch of tinnitus was also in accordance with the disturbed frequency in the hearing threshold.

Effects of Coupled Rolling and Pitching Oscillations on Transonic Shock-Induced Vortex-Breakdown Flow of a Delta Wing

Science.gov (United States)

Kandil, Osama A.; Menzies, Margaret A.

1996-01-01

Unsteady, transonic vortex-breakdown flow over a 65 deg. sharp edged, cropped-delta wing of zero thickness undergoing forced coupled pitching and rolling oscillations is investigated computationally. The initial condition of the flow is characterized by a transverse terminating shock which induces of the leading edge vortex cores to breakdown. The computational investigation uses the time-accurate solution of the laminar, unsteady, compressible, full Navier-Stokes equations with the implicit, upwind, Roe flux-difference splitting, finite-volume scheme. The main focus is to analyze the effects of coupled motion on the wing response and vortex-breakdown flow by varying oscillation frequency and phase angle while keeping the maximum pitch and roll amplitude equal.

Memory for vocal tempo and pitch.

Science.gov (United States)

Boltz, Marilyn G

2017-11-01

Two experiments examined the ability to remember the vocal tempo and pitch of different individuals, and the way this information is encoded into the cognitive system. In both studies, participants engaged in an initial familiarisation phase while attending was systematically directed towards different aspects of speakers' voices. Afterwards, they received a tempo or pitch recognition task. Experiment 1 showed that tempo and pitch are both incidentally encoded into memory at levels comparable to intentional learning, and no performance deficit occurs with divided attending. Experiment 2 examined the ability to recognise pitch or tempo when the two dimensions co-varied and found that the presence of one influenced the other: performance was best when both dimensions were positively correlated with one another. As a set, these findings indicate that pitch and tempo are automatically processed in a holistic, integral fashion [Garner, W. R. (1974). The processing of information and structure. Potomac, MD: Erlbaum.] which has a number of cognitive implications.

Individual Pitch Control Using LIDAR Measurements

DEFF Research Database (Denmark)

Mirzaei, Mahmood; Henriksen, Lars Christian; Poulsen, Niels Kjølstad

2012-01-01

In this work the problem of individual pitch control of a variable-speed variable-pitch wind turbine in the full load region is considered. Model predictive control (MPC) is used to solve the problem. However as the plant is nonlinear and time varying, a new approach is proposed to simplify......-of-plane blade root bending moments and a better transient response compared to a benchmark PI individual pitch controller....

Comparison between OpenFOAM CFD & BEM theory for variable speed – variable pitch HAWT

Directory of Open Access Journals (Sweden)

ElQatary Islam

2014-01-01

Full Text Available OpenFoam is used to compare computational fluid dynamics (CFD with blade element momentum theory (BEM for a variable speed - variable pitch HAWT (Horizontal Axis Wind Turbine. The wind turbine is first designed using the BEM to determine the blade chord, twist and operating conditions. The wind turbine blade has an outer diameter of 14 m, uses a NACA 63–415 profile for the entire blade and root to tip twist distribution of 15deg (Figure 3. The RPM varies from 20–75 for freestream velocities varying between 3–10.5 m/s (variable speed and a constant RPM of 78.78 for velocities ranging between 11–25 m/s (variable pitch. OpenFOAM is used to investigate the wind turbine performance at several operating points including cut-in wind speed (3 m/s, rated wind speed (10.5 m/s and in the variable pitch zone. Simulation results show that in the variable-speed operating range, both CFD and BEM compare reasonably well. This agreement can be attributed to the fact that the complex three-dimensional flow around the turbine blades can be split into two radial segments. For radii less than the mid-span, the flow is three-dimensional, whereas for radii greater than the mid-span, the flow is approximately two-dimensional. Since the majority of the power is produced from sections beyond the mid-span, the agreement between CFD and BEM is reasonable. For the variable-pitch operating range the CFD results and BEM deviate considerably. In this case the majority of the power is produced from the inner sections in which the flow is three-dimensional and can no longer be predicted by the BEM. The results show that differences in pitch angles up to 10deg can result to regulate the power for high wind speeds in the variable-pitch operation zone.

Pitch memory, labelling and disembedding in autism.

Science.gov (United States)

Heaton, Pamela

2003-05-01

Autistic musical savants invariably possess absolute pitch ability and are able to disembed individual musical tones from chords. Enhanced pitch discrimination and memory has been found in non-savant individuals with autism who also show superior performance on visual disembedding tasks. These experiments investigate the extent that enhanced disembedding ability will be found within the musical domain in autism. High-functioning children with autism, together with age- and intelligence-matched controls, participated in three experiments testing pitch memory, labelling and chord disembedding. The findings from experiment 1 showed enhanced pitch memory and labelling in the autism group. In experiment 2, when subjects were pre-exposed to labelled individual tones, superior chord segmentation was also found. However, in experiment 3, when disembedding performance was less reliant on pitch memory, no group differences emerged and the children with autism, like controls, perceived musical chords holistically. These findings indicate that pitch memory and labelling is superior in autism and can facilitate performance on musical disembedding tasks. However, when task performance does not rely on long-term pitch memory, autistic children, like controls, succumb to the Gestalt qualities of chords.

Physicochemical characterization of pitches by differential scanning calorimetry

Energy Technology Data Exchange (ETDEWEB)

Lahaye, J.; Ehrburger, P.; Saint-Romain, J.L.; Couderc, P.

1987-11-01

The glass transition characterization of pitches has been studied by differential scanning calorimetry (d.s.c.). Experimental results and theoretical considerations indicate that: (1) the average molecular mass of pitches can be characterized by the apparent activation energy of the relaxation phenomenon of pitch molecules; (2) the molecular polydispersity is correlated with the width of the glass transition. Characterization of pitch by d.s.c. is well adapted to follow pitch transformation during heat treatment. 6 refs., 6 figs., 4 tabs.

A Neuronal Network Model for Pitch Selectivity and Representation

OpenAIRE

Huang, Chengcheng; Rinzel, John

2016-01-01

Pitch is a perceptual correlate of periodicity. Sounds with distinct spectra can elicit the same pitch. Despite the importance of pitch perception, understanding the cellular mechanism of pitch perception is still a major challenge and a mechanistic model of pitch is lacking. A multi-stage neuronal network model is developed for pitch frequency estimation using biophysically-based, high-resolution coincidence detector neurons. The neuronal units respond only to highly coincident input among c...

Energy and pitch-angle dispersions of LLBL/cusp ions seen at middle altitudes: predictions by the open magnetosphere model

Directory of Open Access Journals (Sweden)

M. Lockwood

1997-12-01

Full Text Available Numerical simulations are presented of the ion distribution functions seen by middle-altitude spacecraft in the low-latitude boundary layer (LLBL and cusp regions when reconnection is, or has recently been, taking place at the equatorial magnetopause. From the evolution of the distribution function with time elapsed since the field line was opened, both the observed energy/observation-time and pitch-angle/energy dispersions are well reproduced. Distribution functions showing a mixture of magnetosheath and magnetospheric ions, often thought to be a signature of the LLBL, are found on newly opened field lines as a natural consequence of the magnetopause effects on the ions and their flight times. In addition, it is shown that the extent of the source region of the magnetosheath ions that are detected by a satellite is a function of the sensitivity of the ion instrument . If the instrument one-count level is high (and/or solar-wind densities are low, the cusp ion precipitation detected comes from a localised region of the mid-latitude magnetopause (around the magnetic cusp, even though the reconnection takes place at the equatorial magnetopause. However, if the instrument sensitivity is high enough, then ions injected from a large segment of the dayside magnetosphere (in the relevant hemisphere will be detected in the cusp. Ion precipitation classed as LLBL is shown to arise from the low-latitude magnetopause, irrespective of the instrument sensitivity. Adoption of threshold flux definitions has the same effect as instrument sensitivity in artificially restricting the apparent source regionKey words. Low-latitude boundary layer · Cusp regions · Open magnetosphere model · Mid-altitudes

Structural characterization of heat treated pitch by solid state /sup 13/C nuclear magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sfihi, H.; Tougne, P.; Legrand, A.P.; Couderc, P.; Saint-Romain, J.L.

1988-12-01

The objective of this paper is to determine structural parameters (aromaticity factor, fractions of protonated and non-protonated aromatic carbons) of some pitches, and to follow their evolution as a function of the heat treatment duration. For such a determination, /sup 13/C-/sup 1/H cross polarization combined with magic angle spinning and dipolar dephasing (CP/MAS/DD) NMR was used. 15 refs., 4 figs., 1 tab.

Characterization of pitches by differential scanning calorimetry

Energy Technology Data Exchange (ETDEWEB)

Ehrburger, P.; Martin, C.; Lahaye, J.; Saint-Romain, J.L.; Couderc, P.

1988-12-01

Pitch materials have generally a very complex composition with molecular mass ranging from a few hundred to several thousands units. In order to characterize these materials their properties related to the glassy transformation, in particular to enthalpy relaxation, have been investigated. Solvent soluble fractions have been characterized by differential scanning calorimetry (DSC). As with polymeric materials, enthalpy relaxation can provide information about pitches and the interactions occurring between the different types of molecules present in the pitch: mean molecular size, structural factor, molecular-size distribution. The determination of glass transition properties provides a useful means for the characterization of pitch and of their solvent extracts. It also permits insight into the complex reactions which occur when pitch materials are heat-treated. 7 refs., 2 figs., 3 tabs.

Method of producing pitch (distillation residue)

Energy Technology Data Exchange (ETDEWEB)

Stepanenko, M.A.; Belkina, T.V.; Krysin, V.P.

1979-08-15

A method is proposed for producing pitch by mixing hard coal pitch with anthracene fraction and thermal treatment of the mixture. The method is distinguished in that in order to increase the quality of the pitch, the anthracene fraction is subjected to thermal treatment at 250-300/sup 0/ for 10-13 hours in the presence of air. This duration of heat treatment allows one to build up in the anthracene fraction up to 20-24% of material which is not soluble and toluene, without the formation of products which are not soluble in quinoline. The fraction prepared in this manner is inserted into the initial pitch in the ratio 1:2 up to 1:9, the mixture is subject to heat treatment at temperature 360-380/sup 0/ and air consumption 7-91/kgX hours until the production of pitch with softening temperature of 85-90/sup 0/. As the initial raw material we used pitch with softening temperature of 60/sup 0/, content of substances which are not soluble in quinoline, 2.0% which are not soluble and toluene 20.6% and coking residue of 49.2%. Example. 80 grams of anthracene fraction is added to 320 grams of pitch. The anthracene fraction is subjected previously to heat treatment at 300/sup 0/ for 13 hours in the presence of air, supplied in the amount of 9 liters per hour. As a result of the heat treatment of the content of materials which are not soluble in toluence in the anthracene fraction is 24.0%, in quinoline it is 0.1%. The ratio of a pitch and thermally treated anthracene fraction in the mixture was 4:l. The produced mixture was subjected to heat treatment at 360/sup 0/ for 1.5 hours with air supply in the amount of 7 liters/ kilograms/hours. Pitch is produced with the following characteristics: softening temperature 88/sup 0/, content of substances which are not soluble in toluene 32.5%, in quinilone, 6.0%, coking residue, 56.7%. The invention can be used in the chemical coking and petrochemical industry.

Effects of Game Pitch Count and Body Mass Index on Pitching Biomechanics in 9- to 10-Year-Old Baseball Athletes.

Science.gov (United States)

Darke, Jim D; Dandekar, Eshan M; Aguinaldo, Arnel L; Hazelwood, Scott J; Klisch, Stephen M

2018-04-01

Pitching while fatigued and body composition may increase the injury risk in youth and adult pitchers. However, the relationships between game pitch count, biomechanics, and body composition have not been reported for a study group restricted to 9- to 10-year-old athletes. During a simulated game with 9- to 10-year-old athletes, (1) participants will experience biomechanical signs of fatigue, and (2) shoulder and elbow kinetics will correlate with body mass index (BMI). Descriptive laboratory study. Thirteen 9- to 10-year-old youth baseball players pitched a simulated game (75 pitches). Range of motion and muscular output tests were conducted before and after the simulated game to quantify fatigue. Kinematic parameters at foot contact, maximum external rotation, and maximum internal rotation velocity (MIRV), as well as maximum shoulder and elbow kinetics between foot contact and MIRV were compared at pitches 1-5, 34-38, and 71-75. Multivariate analyses of variance were used to test the first hypothesis, and linear regressions were used to test the second hypothesis. MIRV increased from pitches 1-5 to 71-75 ( P = .007), and head flexion at MIRV decreased from pitches 1-5 to 34-38 ( P = .022). Maximum shoulder horizontal adduction, external rotation, and internal rotation torques increased from pitches 34-38 to 71-75 ( P = .031, .023, and .021, respectively). Shoulder compression force increased from pitches 1-5 to 71-75 ( P = .011). Correlations of joint torque/force with BMI were found at every pitch period: for example, shoulder internal rotation ( R 2 = 0.93, P biomechanics for 9- to 10-year-old baseball pitchers and may be used in future studies to improve evidence-based injury prevention guidelines.

High Angle Mining System. Final research report, Sep 80-Jun 83

Energy Technology Data Exchange (ETDEWEB)

Christofferson, D.

1983-06-01

Under Bureau of Mines Contract JO-133925, ESD Corporation developed the High Angle Mining System (HAMS) as a method of extracting coal from seams varying widely in thickness and pitch. The system would normally be employed to extract coal lying beyond the economic limit of a strip or open-pit highwall. It is a surface-controlled operation involving no underground personnel. The HAMS can significantly increase the reserve base of coal that can be economically surface mined. A number of open-pit or surface mines which have moderately or steeply pitched seams were visited and studied. Existing technology was reviewed to identify systems or system components which merited further consideration for the development of the HAMS concept. Conventional and innovative approaches based on augering and two approaches based on slackline excavation were developed in sufficient detail to enable comparison on the basis of operational limitation, recovery ratio, productivity, and economy. The slackline excavator concept employing a projectile bucket was selected as the best approach. The capability of economically mining pitched seams of coal with the HAMS was demonstrated.

Complex-tone pitch representations in the human auditory system

DEFF Research Database (Denmark)

Bianchi, Federica

in listeners with SNHL, it is likely that HI listeners rely on the enhanced envelope cues to retrieve the pitch of unresolved harmonics. Hence, the relative importance of pitch cues may be altered in HI listeners, whereby envelope cues may be used instead of TFS cues to obtain a similar performance in pitch......Understanding how the human auditory system processes the physical properties of an acoustical stimulus to give rise to a pitch percept is a fascinating aspect of hearing research. Since most natural sounds are harmonic complex tones, this work focused on the nature of pitch-relevant cues...... that are necessary for the auditory system to retrieve the pitch of complex sounds. The existence of different pitch-coding mechanisms for low-numbered (spectrally resolved) and high-numbered (unresolved) harmonics was investigated by comparing pitch-discrimination performance across different cohorts of listeners...

Sensorimotor Mismapping in Poor-pitch Singing.

Science.gov (United States)

He, Hao; Zhang, Wei-Dong

2017-09-01

This study proposes that there are two types of sensorimotor mismapping in poor-pitch singing: erroneous mapping and no mapping. We created operational definitions for the two types of mismapping based on the precision of pitch-matching and predicted that in the two types of mismapping, phonation differs in terms of accuracy and the dependence on the articulation consistency between the target and the intended vocal action. The study aimed to test this hypothesis by examining the reliability and criterion-related validity of the operational definitions. A within-subject design was used in this study. Thirty-two participants identified as poor-pitch singers were instructed to vocally imitate pure tones and to imitate their own vocal recordings with the same articulation as self-targets and with different articulation from self-targets. Definitions of the types of mismapping were demonstrated to be reliable with the split-half approach and to have good criterion-related validity with findings that pitch-matching with no mapping was less accurate and more dependent on the articulation consistency between the target and the intended vocal action than pitch-matching with erroneous mapping was. Furthermore, the precision of pitch-matching was positively associated with its accuracy and its dependence on articulation consistency when mismapping was analyzed on a continuum. Additionally, the data indicated that the self-imitation advantage was a function of articulation consistency. Types of sensorimotor mismapping lead to pitch-matching that differs in accuracy and its dependence on the articulation consistency between the target and the intended vocal action. Additionally, articulation consistency produces the self-advantage. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Effect of Pitching Consecutive Days in Youth Fast-Pitch Softball Tournaments on Objective Shoulder Strength and Subjective Shoulder Symptoms.

Science.gov (United States)

Skillington, S Andrew; Brophy, Robert H; Wright, Rick W; Smith, Matthew V

2017-05-01

The windmill pitching motion has been associated with risk for shoulder injury. Because there are no pitching limits on youth fast-pitch softball pitchers, these athletes often pitch multiple games across consecutive days. Strength changes, fatigue levels, and shoulder pain that develop among female fast-pitch pitchers over the course of consecutive days of pitching have not been investigated. Over the course of 2- and 3-day fast-pitch softball tournaments, pitchers will develop progressive objective weakness and increased subjective shoulder fatigue and pain without complete recovery between days. Cross-sectional study; Level of evidence, 3. Fourteen female fast-pitch softball pitchers between the ages of 14 and 18 years were evaluated for strength and fatigue changes across 2- and 3-day tournaments. At the beginning and end of each day of tournament play, pitchers were asked to quantify shoulder fatigue and shoulder pain levels of their dominant throwing arm using a 10-point visual analog scale (VAS). Shoulder abduction, flexion, external rotation, internal rotation, elbow flexion, and elbow extension strength measurements were gathered using a handheld dynamometer. Over the course of an average single day of tournament participation, pitchers developed significant increases in VAS scores for shoulder fatigue (median, 2.0; 95% CI, 1.3-3.0) and pain (median, 1.3; 95% CI, 0.5-2.3) and significant strength loss in all tested motions. Pitchers also developed significant increases in VAS shoulder fatigue (median, 3.5; 95% CI, 1.5-5.5), VAS shoulder pain (median, 2.5; 95% CI, 1.0-4.5), and strength loss in all tested motions over the entire tournament. Shoulder pain, fatigue, and strength do not fully recover between days. The accumulation of subjective shoulder pain and fatigue over the course of tournament play were closely correlated. Among youth female fast-pitch softball pitchers, there is a progressive increase in shoulder fatigue, pain, and weakness over the

A developmental study of latent absolute pitch memory.

Science.gov (United States)

Jakubowski, Kelly; Müllensiefen, Daniel; Stewart, Lauren

2017-03-01

The ability to recall the absolute pitch level of familiar music (latent absolute pitch memory) is widespread in adults, in contrast to the rare ability to label single pitches without a reference tone (overt absolute pitch memory). The present research investigated the developmental profile of latent absolute pitch (AP) memory and explored individual differences related to this ability. In two experiments, 288 children from 4 to12 years of age performed significantly above chance at recognizing the absolute pitch level of familiar melodies. No age-related improvement or decline, nor effects of musical training, gender, or familiarity with the stimuli were found in regard to latent AP task performance. These findings suggest that latent AP memory is a stable ability that is developed from as early as age 4 and persists into adulthood.

Contact-angle hysteresis on periodic microtextured surfaces: Strongly corrugated liquid interfaces.

Science.gov (United States)

Iliev, Stanimir; Pesheva, Nina

2016-06-01

We study numerically the shapes of a liquid meniscus in contact with ultrahydrophobic pillar surfaces in Cassie's wetting regime, when the surface is covered with identical and periodically distributed micropillars. Using the full capillary model we obtain the advancing and the receding equilibrium meniscus shapes when the cross-sections of the pillars are both of square and circular shapes, for a broad interval of pillar concentrations. The bending of the liquid interface in the area between the pillars is studied in the framework of the full capillary model and compared to the results of the heterogeneous approximation model. The contact angle hysteresis is obtained when the three-phase contact line is located on one row (block case) or several rows (kink case) of pillars. It is found that the contact angle hysteresis is proportional to the line fraction of the contact line on pillars tops in the block case and to the surface fraction for pillar concentrations 0.1-0.5 in the kink case. The contact angle hysteresis does not depend on the shape (circular or square) of the pillars cross-section. The expression for the proportionality of the receding contact angle to the line fraction [Raj et al., Langmuir 28, 15777 (2012)LANGD50743-746310.1021/la303070s] in the case of block depinning is theoretically substantiated through the capillary force, acting on the solid plate at the meniscus contact line.

Mathematical modeling and design parameters of crushing machines with variable-pitch helix of the screw

Directory of Open Access Journals (Sweden)

Pelenko V. V.

2017-11-01

Full Text Available From the point of view of the effectiveness of the top cutting unit, the helix angle in the end portion of the screw is the most important and characteristic parameter, as it determines the pressure of the meat material in the zone of interaction of a knife and grate. The importance of solving the problem of mathematical modeling of geometry is due to the need to address the problem of minimizing the reverse flow of the food material when injecting into the cutting zone, as the specified effect of "locking" significantly reduces the performance of the transfer process, increases energy consumption of the equipment and entails the deterioration of the quality of the raw materials output. The problem of determining the length of the helix variable pitch for screw chopper food materials has been formulated and solved by methods of differential geometry. The task of correct description of the law of changing the angle of helix inclination along its length has been defined in this case as a key to provide the required dependence of this angle tangent on the angle of the radius-vector of the circle. It has been taken into account that the reduction in the pitch of the screw in the direction of the product delivery should occur at a decreasing rate. The parametric equation of the helix has been written in the form of three functional dependencies of the corresponding cylindrical coordinates. Based on the wide range analysis and significant number of models of tops from different manufacturers the boundaries of possible changes in the angles of inclination of the helical line of the first and last turns of the screw have been identified. The auger screw length is determined mathematically in the form of an analytical relationship and both as a function of the variable angle of its rise, and as a function of the rotation angle of the radius-vector of the circle generatrix, which makes it possible to expand the design possibilities of this node. Along

Pitch modelling for the Nguni languages

CSIR Research Space (South Africa)

Govender, N

2007-06-01

Full Text Available Govender ngovender@csir.co.za, Etienne Barnard ebarnard@csir.co.za, Marelie Davel mdavel@csir.co.za by varying the levels of pitch, intensity and duration in the voice. An overview of intonation as observed in a variety of languages is provided in [1... nature of laryngograph data in voiced speech) and thus either could be used as the basis for the experiments. The pitch values extracted by Yin for all the laryngograph databases was consequently used as the basis for our comparisons. Pitch...

Language experience enhances early cortical pitch-dependent responses

Science.gov (United States)

Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

2014-01-01

Pitch processing at cortical and subcortical stages of processing is shaped by language experience. We recently demonstrated that specific components of the cortical pitch response (CPR) index the more rapidly-changing portions of the high rising Tone 2 of Mandarin Chinese, in addition to marking pitch onset and sound offset. In this study, we examine how language experience (Mandarin vs. English) shapes the processing of different temporal attributes of pitch reflected in the CPR components using stimuli representative of within-category variants of Tone 2. Results showed that the magnitude of CPR components (Na-Pb and Pb-Nb) and the correlation between these two components and pitch acceleration were stronger for the Chinese listeners compared to English listeners for stimuli that fell within the range of Tone 2 citation forms. Discriminant function analysis revealed that the Na-Pb component was more than twice as important as Pb-Nb in grouping listeners by language affiliation. In addition, a stronger stimulus-dependent, rightward asymmetry was observed for the Chinese group at the temporal, but not frontal, electrode sites. This finding may reflect selective recruitment of experience-dependent, pitch-specific mechanisms in right auditory cortex to extract more complex, time-varying pitch patterns. Taken together, these findings suggest that long-term language experience shapes early sensory level processing of pitch in the auditory cortex, and that the sensitivity of the CPR may vary depending on the relative linguistic importance of specific temporal attributes of dynamic pitch. PMID:25506127

Estimates of pitch strength for musicians and nonmusicians

Science.gov (United States)

Clarkson, Marsha G.; Zettler, Cynthia M.; Follmer, Michelle J.; Faulk, Margaret; Takagi, Michael J.

2003-04-01

To measure the strength of the pitch of iterated rippled noise (IRN), 19 adults were tested in an operant conditioning procedure. Seven adults had music training and currently played an instrument; 12 adults had no training and did not currently play an instrument. To generate IRN, a 500-ms Gaussian noise stimulus was delayed by 5 or 6 ms (pitches of 200 or 166 Hz) and added to the original for 16 iterations. IRN stimuli having one delay were presented repeatedly. On signal trials the delay changed for 6 s. Stimulus level roved from 63-67 dBA (background of 28 dBA). Adults learned to press a button when the stimulus changed. Testing started with IRN stimuli having 0-dB attenuation (i.e., maximal pitch strength). Stimuli having weaker pitches (i.e., progressively greater attenuation applied to the delayed noise) followed. Strength of pitch was quantified as the maximum attenuation for which pitch was discerned. For each subject, threshold attenuation for pitch strength was extrapolated as the 71% point on a psychometric function depicting percent correct performance as a function of attenuation. Mean thresholds revealed that the pitch percept was similar for both nonmusically trained (18.70 dB) and musically trained adults (18.73 dB).

Language-dependent changes in pitch-relevant neural activity in the auditory cortex reflect differential weighting of temporal attributes of pitch contours

Science.gov (United States)

Krishnan, Ananthanarayan; Gandour, Jackson T.; Xu, Yi; Suresh, Chandan H.

2016-01-01

There remains a gap in our knowledge base about neural representation of pitch attributes that occur between onset and offset of dynamic, curvilinear pitch contours. The aim is to evaluate how language experience shapes processing of pitch contours as reflected in the amplitude of cortical pitch-specific response components. Responses were elicited from three nonspeech, bidirectional (falling-rising) pitch contours representative of Mandarin Tone 2 varying in location of the turning point with fixed onset and offset. At the frontocentral Fz electrode site, Na–Pb and Pb–Nb amplitude of the Chinese group was larger than the English group for pitch contours exhibiting later location of the turning point relative to the one with the earliest location. Chinese listeners’ amplitude was also greater than that of English in response to those same pitch contours with later turning points. At lateral temporal sites (T7/T8), Na–Pb amplitude was larger in Chinese listeners relative to English over the right temporal site. In addition, Pb–Nb amplitude of the Chinese group showed a rightward asymmetry. The pitch contour with its turning point located about halfway of total duration evoked a rightward asymmetry regardless of group. These findings suggest that neural mechanisms processing pitch in the right auditory cortex reflect experience-dependent modulation of sensitivity to weighted integration of changes in acceleration rates of rising and falling sections and the location of the turning point. PMID:28713201

Relating binaural pitch perception to the individual listener's auditory profile.

Science.gov (United States)

Santurette, Sébastien; Dau, Torsten

2012-04-01

The ability of eight normal-hearing listeners and fourteen listeners with sensorineural hearing loss to detect and identify pitch contours was measured for binaural-pitch stimuli and salience-matched monaurally detectable pitches. In an effort to determine whether impaired binaural pitch perception was linked to a specific deficit, the auditory profiles of the individual listeners were characterized using measures of loudness perception, cognitive ability, binaural processing, temporal fine structure processing, and frequency selectivity, in addition to common audiometric measures. Two of the listeners were found not to perceive binaural pitch at all, despite a clear detection of monaural pitch. While both binaural and monaural pitches were detectable by all other listeners, identification scores were significantly lower for binaural than for monaural pitch. A total absence of binaural pitch sensation coexisted with a loss of a binaural signal-detection advantage in noise, without implying reduced cognitive function. Auditory filter bandwidths did not correlate with the difference in pitch identification scores between binaural and monaural pitches. However, subjects with impaired binaural pitch perception showed deficits in temporal fine structure processing. Whether the observed deficits stemmed from peripheral or central mechanisms could not be resolved here, but the present findings may be useful for hearing loss characterization.

Timing matters: The processing of pitch relations

Directory of Open Access Journals (Sweden)

Annekathrin eWeise

2014-06-01

Full Text Available The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms, impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g. pitch of 2nd tone of a pair higher than pitch of 1st tone, while absolute pitch values varied across pairs. We measured the Mismatch Negativity (MMN; the brain’s error signal to auditory regularity violations to 2nd tones that rarely violated the pitch relation (e.g. pitch of 2nd tone lower. A Short condition in which tone duration (90 ms and stimulus onset asynchrony between the tones of a pair were short (110 ms was compared to two conditions, where this onset asynchrony was long (510 ms. In the Long Gap condition the tone durations were identical to Short (90 ms, but the silent interval was prolonged by 400 ms. In Long Tone the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms. Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing.

Timing matters: the processing of pitch relations

Science.gov (United States)

Weise, Annekathrin; Grimm, Sabine; Trujillo-Barreto, Nelson J.; Schröger, Erich

2014-01-01

The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms), impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g., pitch of second tone of a pair higher than pitch of first tone, while absolute pitch values varied across pairs). We measured the mismatch negativity (MMN; the brain’s error signal to auditory regularity violations) to second tones that rarely violated the pitch relation (e.g., pitch of second tone lower). A Short condition in which tone duration (90 ms) and stimulus onset asynchrony between the tones of a pair were short (110 ms) was compared to two conditions, where this onset asynchrony was long (510 ms). In the Long Gap condition, the tone durations were identical to Short (90 ms), but the silent interval was prolonged by 400 ms. In Long Tone, the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms). Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing. PMID:24966823

Impaired short-term memory for pitch in congenital amusia.

Science.gov (United States)

Tillmann, Barbara; Lévêque, Yohana; Fornoni, Lesly; Albouy, Philippe; Caclin, Anne

2016-06-01

Congenital amusia is a neuro-developmental disorder of music perception and production. The hypothesis is that the musical deficits arise from altered pitch processing, with impairments in pitch discrimination (i.e., pitch change detection, pitch direction discrimination and identification) and short-term memory. The present review article focuses on the deficit of short-term memory for pitch. Overall, the data discussed here suggest impairments at each level of processing in short-term memory tasks; starting with the encoding of the pitch information and the creation of the adequate memory trace, the retention of the pitch traces over time as well as the recollection and comparison of the stored information with newly incoming information. These impairments have been related to altered brain responses in a distributed fronto-temporal network, associated with decreased connectivity between these structures, as well as in abnormalities in the connectivity between the two auditory cortices. In contrast, amusic participants׳ short-term memory abilities for verbal material are preserved. These findings show that short-term memory deficits in congenital amusia are specific to pitch, suggesting a pitch-memory system that is, at least partly, separated from verbal memory. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

A perceptual pitch boundary in a non-human primate

Directory of Open Access Journals (Sweden)

Olivier eJoly

2014-09-01

Full Text Available Pitch is an auditory percept critical to the perception of music and speech, and for these harmonic sounds, pitch is closely related to the repetition rate of the acoustic wave. This paper reports a test of the assumption that non-human primates and especially rhesus monkeys perceive the pitch of these harmonic sounds much as humans do. A new procedure was developed to train macaques to discriminate the pitch of harmonic sounds and thereby demonstrate that the lower limit for pitch perception in macaques is close to 30 Hz, as it is in humans. Moreover, when the phases of successive harmonics are alternated to cause a pseudo-doubling of the repetition rate, the lower pitch boundary in macaques decreases substantially, as it does in humans. The results suggest that both species use neural firing times to discriminate pitch, at least for sounds with relatively low repetition rates.

Auditory deficits in amusia extend beyond poor pitch perception.

Science.gov (United States)

Whiteford, Kelly L; Oxenham, Andrew J

2017-05-01

Congenital amusia is a music perception disorder believed to reflect a deficit in fine-grained pitch perception and/or short-term or working memory for pitch. Because most measures of pitch perception include memory and segmentation components, it has been difficult to determine the true extent of pitch processing deficits in amusia. It is also unclear whether pitch deficits persist at frequencies beyond the range of musical pitch. To address these questions, experiments were conducted with amusics and matched controls, manipulating both the stimuli and the task demands. First, we assessed pitch discrimination at low (500Hz and 2000Hz) and high (8000Hz) frequencies using a three-interval forced-choice task. Amusics exhibited deficits even at the highest frequency, which lies beyond the existence region of musical pitch. Next, we assessed the extent to which frequency coding deficits persist in one- and two-interval frequency-modulation (FM) and amplitude-modulation (AM) detection tasks at 500Hz at slow (f m =4Hz) and fast (f m =20Hz) modulation rates. Amusics still exhibited deficits in one-interval FM detection tasks that should not involve memory or segmentation. Surprisingly, amusics were also impaired on AM detection, which should not involve pitch processing. Finally, direct comparisons between the detection of continuous and discrete FM demonstrated that amusics suffer deficits in both coding and segmenting pitch information. Our results reveal auditory deficits in amusia extending beyond pitch perception that are subtle when controlling for memory and segmentation, and are likely exacerbated in more complex contexts such as musical listening. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wing-pitch modulation in maneuvering fruit flies is explained by an interplay between aerodynamics and a torsional spring

Science.gov (United States)

Beatus, Tsevi; Cohen, Itai

2015-08-01

While the wing kinematics of many flapping insects have been well characterized, understanding the underlying sensory, neural, and physiological mechanisms that determine these kinematics is still a challenge. Two main difficulties in understanding the physiological mechanisms arise from the complexity of the interaction between a flapping wing and its own unsteady flow, as well as the intricate mechanics of the insect wing hinge, which is among the most complicated joints in the animal kingdom. These difficulties call for the application of reduced-order approaches. Here this strategy is used to model the torques exerted by the wing hinge along the wing-pitch axis of maneuvering fruit flies as a damped torsional spring with elastic and damping coefficients as well as a rest angle. Furthermore, we model the air flows using simplified quasistatic aerodynamics. Our findings suggest that flies take advantage of the passive coupling between aerodynamics and the damped torsional spring to indirectly control their wing-pitch kinematics by modulating the spring parameters. The damped torsional-spring model explains the changes measured in wing-pitch kinematics during roll correction maneuvers through modulation of the spring damping and elastic coefficients. These results, in conjunction with the previous literature, indicate that flies can accurately control their wing-pitch kinematics on a sub-wing-beat time scale by modulating all three effective spring parameters on longer time scales.

Tinnitus pitch and acoustic trauma

Energy Technology Data Exchange (ETDEWEB)

Cahani, M; Paul, G; Shahar, A

1983-01-01

Fifty-six subjects complaining of tinnitus underwent an audiometric test and a test for identifying the analogous pitch of their tinnitus. All of the subjects reported that they had been exposed to noise in the past. The subjects were divided into two groups on the basis of their audiometric test results. Group P was composed of subjects who showed a sensorineural hearing loss typical of acoustic trauma. Group N was composed of subjects whose hearing was within normal limits. The pitch of the tinnitus in group P was concentrated in the high-frequency range, whereas in group N tinnitus pitch values were distributed over the low and mid-audiometric frequency spectrum. It was deduced that different processes are involved in the generation of tinnitus in the two groups.

Binaural Pitch Fusion in Bilateral Cochlear Implant Users.

Science.gov (United States)

Reiss, Lina A J; Fowler, Jennifer R; Hartling, Curtis L; Oh, Yonghee

Binaural pitch fusion is the fusion of stimuli that evoke different pitches between the ears into a single auditory image. Individuals who use hearing aids or bimodal cochlear implants (CIs) experience abnormally broad binaural pitch fusion, such that sounds differing in pitch by as much as 3-4 octaves are fused across ears, leading to spectral averaging and speech perception interference. The goal of this study was to determine if adult bilateral CI users also experience broad binaural pitch fusion. Stimuli were pulse trains delivered to individual electrodes. Fusion ranges were measured using simultaneous, dichotic presentation of reference and comparison stimuli in opposite ears, and varying the comparison stimulus to find the range that fused with the reference stimulus. Bilateral CI listeners had binaural pitch fusion ranges varying from 0 to 12 mm (average 6.1 ± 3.9 mm), where 12 mm indicates fusion over all electrodes in the array. No significant correlations of fusion range were observed with any subject factors related to age, hearing loss history, or hearing device history, or with any electrode factors including interaural electrode pitch mismatch, pitch match bandwidth, or within-ear electrode discrimination abilities. Bilateral CI listeners have abnormally broad fusion, similar to hearing aid and bimodal CI listeners. This broad fusion may explain the variability of binaural benefits for speech perception in quiet and in noise in bilateral CI users.

Numerical study of hub taper angle on podded propeller performance

International Nuclear Information System (INIS)

Islam, M.F.; Veitch, B.; Bose, N.; Liu, P.

2005-01-01

Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

Statistically Efficient Methods for Pitch and DOA Estimation

DEFF Research Database (Denmark)

Jensen, Jesper Rindom; Christensen, Mads Græsbøll; Jensen, Søren Holdt

2013-01-01

, it was recently considered to estimate the DOA and pitch jointly. In this paper, we propose two novel methods for DOA and pitch estimation. They both yield maximum-likelihood estimates in white Gaussian noise scenar- ios, where the SNR may be different across channels, as opposed to state-of-the-art methods......Traditionally, direction-of-arrival (DOA) and pitch estimation of multichannel, periodic sources have been considered as two separate problems. Separate estimation may render the task of resolving sources with similar DOA or pitch impossible, and it may decrease the estimation accuracy. Therefore...

Load consequences when sweeping blades - A case study of a 5 MW pitch controlled wind turbine

Energy Technology Data Exchange (ETDEWEB)

Verelst, D.R.S.; Larsen, Torben J.

2010-08-15

The generic 5 MW NREL wind turbine model is used in Risoe's aeroelastic simulator HAWC2 to investigate 120 different swept blade configurations (forward and backward sweep). Sensitivity for 2 different controllers is considered as well. Backward sweep results in a pitch to feather torsional moment of the blade, effectively reducing blade twist angles under increased loading. This behaviour results in decreased flap-wise fatigue and extreme loads, an increase for edge-wise fatigue loading and status quo or slight decrease in extreme loads (depending on the controller). Tower base and shaft-end bending moments are reduced as well. Forward sweep leads to an increase in angle of attack under loading. For a pitch controlled turbine this leads to an increase in fatigue and extreme loading in all cases. A controller inflicted instability is present for the more extreme forward swept cases. Due to the shape of considered sweep curves, an inherent and significant increase in torsional blade root bending moment is noted. A boomerang shaped sweep curve is proposed to counteract this problematic increased loading. Controller sensitivity shows that adding sweep affects some loadings differently. Power output is reduced for backward sweep since the blade twist is optimized as a rigid structure, ignoring the torsional deformations which for a swept blade can be significant. (author)

Wind turbine pitch control using ICPSO-PID algorithm

DEFF Research Database (Denmark)

Xu, Chang; Tian, Qiangqiang; Shen, Wen Zhong

2013-01-01

For the traditional simplified first-order pitch-control system model, it is difficult to describe a real dynamic characteristic of a variable pitch action system, thus a complete high order mathematical model has to be developed for the pitch control of wind turbine generation (WTG). In the paper...... controller parameters quickly; and the feed-forward controller for wind speed can improve dynamics of a pitch-control system; additionally the power controller can allow a wind turbine to have a constant power output as a wind speed is over the rated one. Compared with a conventional PID, the controller...... with ICPSO-PID algorithm has a smaller overshoot, a shorter tuning time and better robustness. The design method proposed in the paper can be applied in a practical electro-hydraulic pitch control system for WTG....

A fundamental residue pitch perception bias for tone language speakers

Science.gov (United States)

Petitti, Elizabeth

A complex tone composed of only higher-order harmonics typically elicits a pitch percept equivalent to the tone's missing fundamental frequency (f0). When judging the direction of residue pitch change between two such tones, however, listeners may have completely opposite perceptual experiences depending on whether they are biased to perceive changes based on the overall spectrum or the missing f0 (harmonic spacing). Individual differences in residue pitch change judgments are reliable and have been associated with musical experience and functional neuroanatomy. Tone languages put greater pitch processing demands on their speakers than non-tone languages, and we investigated whether these lifelong differences in linguistic pitch processing affect listeners' bias for residue pitch. We asked native tone language speakers and native English speakers to perform a pitch judgment task for two tones with missing fundamental frequencies. Given tone pairs with ambiguous pitch changes, listeners were asked to judge the direction of pitch change, where the direction of their response indicated whether they attended to the overall spectrum (exhibiting a spectral bias) or the missing f0 (exhibiting a fundamental bias). We found that tone language speakers are significantly more likely to perceive pitch changes based on the missing f0 than English speakers. These results suggest that tone-language speakers' privileged experience with linguistic pitch fundamentally tunes their basic auditory processing.

Heavy vehicle pitch dynamics and suspension tuning

OpenAIRE

Cao, Dongpu; Rakheja, Subhash; Su, Chun-Yi

2008-01-01

The influence of suspension tuning of passenger cars on bounce and pitch ride performance has been explored in a number of studies, while only minimal efforts have been made for establishing similar rules for heavy vehicles. This study aims to explore pitch dynamics and suspension tunings of a two-axle heavy vehicle with unconnected suspension, which could also provide valuable information for heavy vehicles with coupled suspensions. Based on a generalised pitch-plane model of a two-axle heav...

Do Musicians with Perfect Pitch Have More Autism Traits than Musicians without Perfect Pitch? An Empirical Study

DEFF Research Database (Denmark)

Dohn, Anders; Garza-Villarreal, Eduardo A.; Heaton, Pamela

2012-01-01

Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increas...

Discriminating male and female voices: differentiating pitch and gender.

Science.gov (United States)

Latinus, Marianne; Taylor, Margot J

2012-04-01

Gender is salient, socially critical information obtained from faces and voices, yet the brain processes underlying gender discrimination have not been well studied. We investigated neural correlates of gender processing of voices in two ERP studies. In the first, ERP differences were seen between female and male voices starting at 87 ms, in both spatial-temporal and peak analyses, particularly the fronto-central N1 and P2. As pitch differences may drive gender differences, the second study used normal, high- and low-pitch voices. The results of these studies suggested that differences in pitch produced early effects (27-63 ms). Gender effects were seen on N1 (120 ms) with implicit pitch processing (study 1), but were not seen with manipulations of pitch (study 2), demonstrating that N1 was modulated by attention. P2 (between 170 and 230 ms) discriminated male from female voices, independent of pitch. Thus, these data show that there are two stages in voice gender processing; a very early pitch or frequency discrimination and a later more accurate determination of gender at the P2 latency.

Processing of Binaural Pitch Stimuli in Hearing-Impaired Listeners

DEFF Research Database (Denmark)

Santurette, Sébastien; Dau, Torsten

2009-01-01

Binaural pitch is a tonal sensation produced by introducing a frequency-dependent interaural phase shift in binaurally presented white noise. As no spectral cues are present in the physical stimulus, binaural pitch perception is assumed to rely on accurate temporal fine structure coding and intact...... binaural integration mechanisms. This study investigated to what extent basic auditory measures of binaural processing as well as cognitive abilities are correlated with the ability of hearing-impaired listeners to perceive binaural pitch. Subjects from three groups (1: normal-hearing; 2: cochlear...... hearingloss; 3: retro-cochlear impairment) were asked to identify the pitch contour of series of five notes of equal duration, ranging from 523 to 784 Hz, played either with Huggins’ binaural pitch stimuli (BP) or perceptually similar, but monaurally detectable, pitches (MP). All subjects from groups 1 and 2...

Kinematics and kinetics of elite windmill softball pitching.

Science.gov (United States)

Werner, Sherry L; Jones, Deryk G; Guido, John A; Brunet, Michael E

2006-04-01

A significant number of time-loss injuries to the upper extremity in elite windmill softball pitchers has been documented. The number of outings and pitches thrown in 1 week for a softball pitcher is typically far in excess of those seen in baseball pitchers. Shoulder stress in professional baseball pitching has been reported to be high and has been linked to pitching injuries. Shoulder distraction has not been studied in an elite softball pitching population. The stresses on the throwing shoulder of elite windmill pitchers are similar to those found for professional baseball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (120 Hz) video data were collected on rise balls from 24 elite softball pitchers during the 1996 Olympic Games. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing shoulder were calculated. Multiple linear regression analysis was used to relate shoulder stress and pitching mechanics. Shoulder distraction stress averaged 80% of body weight for the Olympic pitchers. Sixty-nine percent of the variability in shoulder distraction can be explained by a combination of 7 parameters related to pitching mechanics. Excessive distraction stress at the throwing shoulder is similar to that found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper extremity kinematics and kinetics for elite softball pitchers has been established.

Selective and divided attention modulates auditory-vocal integration in the processing of pitch feedback errors.

Science.gov (United States)

Liu, Ying; Hu, Huijing; Jones, Jeffery A; Guo, Zhiqiang; Li, Weifeng; Chen, Xi; Liu, Peng; Liu, Hanjun

2015-08-01

Speakers rapidly adjust their ongoing vocal productions to compensate for errors they hear in their auditory feedback. It is currently unclear what role attention plays in these vocal compensations. This event-related potential (ERP) study examined the influence of selective and divided attention on the vocal and cortical responses to pitch errors heard in auditory feedback regarding ongoing vocalisations. During the production of a sustained vowel, participants briefly heard their vocal pitch shifted up two semitones while they actively attended to auditory or visual events (selective attention), or both auditory and visual events (divided attention), or were not told to attend to either modality (control condition). The behavioral results showed that attending to the pitch perturbations elicited larger vocal compensations than attending to the visual stimuli. Moreover, ERPs were likewise sensitive to the attentional manipulations: P2 responses to pitch perturbations were larger when participants attended to the auditory stimuli compared to when they attended to the visual stimuli, and compared to when they were not explicitly told to attend to either the visual or auditory stimuli. By contrast, dividing attention between the auditory and visual modalities caused suppressed P2 responses relative to all the other conditions and caused enhanced N1 responses relative to the control condition. These findings provide strong evidence for the influence of attention on the mechanisms underlying the auditory-vocal integration in the processing of pitch feedback errors. In addition, selective attention and divided attention appear to modulate the neurobehavioral processing of pitch feedback errors in different ways. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Binaural pitch perception in normal-hearing and hearing-impaired listeners

DEFF Research Database (Denmark)

Santurette, Sébastien; Dau, Torsten

2007-01-01

The effects of hearing impairment on the perception of binaural-pitch stimuli were investigated. Several experiments were performed with normal-hearing and hearing-impaired listeners, including detection and discrimination of binaural pitch, and melody recognition using different types of binaural...... pitches. For the normal-hearing listeners, all types of binaural pitches could be perceived immediately and were musical. The hearing-impaired listeners could be divided into three groups based on their results: (a) some perceived all types of binaural pitches, but with decreased salience or musicality...... compared to normal-hearing listeners; (b) some could only perceive the strongest pitch types; (c) some were unable to perceive any binaural pitch at all. The performance of the listeners was not correlated with audibility. Additional experiments investigated the correlation between performance in binaural...

Pitch discrimination associated with phonological awareness: Evidence from congenital amusia.

Science.gov (United States)

Sun, Yanan; Lu, Xuejing; Ho, Hao Tam; Thompson, William Forde

2017-03-13

Research suggests that musical skills are associated with phonological abilities. To further investigate this association, we examined whether phonological impairments are evident in individuals with poor music abilities. Twenty individuals with congenital amusia and 20 matched controls were assessed on a pure-tone pitch discrimination task, a rhythm discrimination task, and four phonological tests. Amusic participants showed deficits in discriminating pitch and discriminating rhythmic patterns that involve a regular beat. At a group level, these individuals performed similarly to controls on all phonological tests. However, eight amusics with severe pitch impairment, as identified by the pitch discrimination task, exhibited significantly worse performance than all other participants in phonological awareness. A hierarchical regression analysis indicated that pitch discrimination thresholds predicted phonological awareness beyond that predicted by phonological short-term memory and rhythm discrimination. In contrast, our rhythm discrimination task did not predict phonological awareness beyond that predicted by pitch discrimination thresholds. These findings suggest that accurate pitch discrimination is critical for phonological processing. We propose that deficits in early-stage pitch discrimination may be associated with impaired phonological awareness and we discuss the shared role of pitch discrimination for processing music and speech.

Pitch Counts in Youth Baseball and Softball: A Historical Review.

Science.gov (United States)

Feeley, Brian T; Schisel, Jessica; Agel, Julie

2018-07-01

Pitching injuries are getting increased attention in the mass media. Many references are made to pitch counts and the role they play in injury prevention. The original purpose of regulating the pitch count in youth baseball was to reduce injury and fatigue to pitchers. This article reviews the history and development of the pitch count limit in baseball, the effect it has had on injury, and the evidence regarding injury rates on softball windmill pitching. Literature search through PubMed, mass media, and organizational Web sites through June 2015. Pitch count limits and rest recommendations were introduced in 1996 after a survey of 28 orthopedic surgeons and baseball coaches showed injuries to baseball pitchers' arms were believed to be from the number of pitches thrown. Follow-up research led to revised recommendations with more detailed guidelines in 2006. Since that time, data show a relationship between innings pitched and upper extremity injury, but pitch type has not clearly been shown to affect injury rates. Current surveys of coaches and players show that coaches, parents, and athletes often do not adhere to these guidelines. There are no pitch count guidelines currently available in softball. The increase in participation in youth baseball and softball with an emphasis on early sport specialization in youth sports activities suggests that there will continue to be a rise in injury rates to young throwers. The published pitch counts are likely to positively affect injury rates but must be adhered to by athletes, coaches, and parents.

Subcortical plasticity following perceptual learning in a pitch discrimination task.

Science.gov (United States)

Carcagno, Samuele; Plack, Christopher J

2011-02-01

Practice can lead to dramatic improvements in the discrimination of auditory stimuli. In this study, we investigated changes of the frequency-following response (FFR), a subcortical component of the auditory evoked potentials, after a period of pitch discrimination training. Twenty-seven adult listeners were trained for 10 h on a pitch discrimination task using one of three different complex tone stimuli. One had a static pitch contour, one had a rising pitch contour, and one had a falling pitch contour. Behavioral measures of pitch discrimination and FFRs for all the stimuli were measured before and after the training phase for these participants, as well as for an untrained control group (n = 12). Trained participants showed significant improvements in pitch discrimination compared to the control group for all three trained stimuli. These improvements were partly specific for stimuli with the same pitch modulation (dynamic vs. static) and with the same pitch trajectory (rising vs. falling) as the trained stimulus. Also, the robustness of FFR neural phase locking to the sound envelope increased significantly more in trained participants compared to the control group for the static and rising contour, but not for the falling contour. Changes in FFR strength were partly specific for stimuli with the same pitch modulation (dynamic vs. static) of the trained stimulus. Changes in FFR strength, however, were not specific for stimuli with the same pitch trajectory (rising vs. falling) as the trained stimulus. These findings indicate that even relatively low-level processes in the mature auditory system are subject to experience-related change.

The characteristic pitch angle distributions of 1 eV to 600 keV protons near the equator based on Van Allen Probes observations

Science.gov (United States)

Yue, C.; Bortnik, J.; Thorne, R. M.; Ma, Q.; An, X.; Chappell, C. R.; Gerrard, A. J.; Lanzerotti, L. J.; Shi, Q.

2017-12-01

Understanding the source and loss processes of various plasma populations is greatly aided by having accurate knowledge of their pitch angle distributions (PADs). Here, we statistically analyze 1 eV to 600 keV hydrogen (H+) PADs near the geomagnetic equator in the inner magnetosphere based on Van Allen Probes measurements, to comprehensively investigate how the H+ PADs vary with different energies, magnetic local times (MLTs), L-shells, and geomagnetic conditions. Our survey clearly indicates four distinct populations with different PADs: (1) a pancake distribution of the plasmaspheric H+ at low L-shells except for dawn sector; (2) a bi-directional field-aligned distribution of the warm plasma cloak; (3) pancake or isotropic distributions of ring current H+; (4) radiation belt particles show pancake, butterfly and isotropic distributions depending on their energy, MLT and L-shell. Meanwhile, the pancake distribution of ring current H+ moves to lower energies as L-shell increases which is primarily caused by adiabatic transport. Furthermore, energetic H+ (> 10 keV) PADs become more isotropic following the substorm injections, indicating wave-particle interactions. The radiation belt H+ butterfly distributions are identified in a narrow energy range of 100 5), which are less significant during quiet times and extend from dusk to dawn sector through midnight during substorms. The different PADs near the equator provide clues of the underlying physical processes that produce the dynamics of these different populations.

Perception and Modeling of Affective Qualities of Musical Instrument Sounds across Pitch Registers.

Science.gov (United States)

McAdams, Stephen; Douglas, Chelsea; Vempala, Naresh N

2017-01-01

Composers often pick specific instruments to convey a given emotional tone in their music, partly due to their expressive possibilities, but also due to their timbres in specific registers and at given dynamic markings. Of interest to both music psychology and music informatics from a computational point of view is the relation between the acoustic properties that give rise to the timbre at a given pitch and the perceived emotional quality of the tone. Musician and nonmusician listeners were presented with 137 tones produced at a fixed dynamic marking (forte) playing tones at pitch class D# across each instrument's entire pitch range and with different playing techniques for standard orchestral instruments drawn from the brass, woodwind, string, and pitched percussion families. They rated each tone on six analogical-categorical scales in terms of emotional valence (positive/negative and pleasant/unpleasant), energy arousal (awake/tired), tension arousal (excited/calm), preference (like/dislike), and familiarity. Linear mixed models revealed interactive effects of musical training, instrument family, and pitch register, with non-linear relations between pitch register and several dependent variables. Twenty-three audio descriptors from the Timbre Toolbox were computed for each sound and analyzed in two ways: linear partial least squares regression (PLSR) and nonlinear artificial neural net modeling. These two analyses converged in terms of the importance of various spectral, temporal, and spectrotemporal audio descriptors in explaining the emotion ratings, but some differences also emerged. Different combinations of audio descriptors make major contributions to the three emotion dimensions, suggesting that they are carried by distinct acoustic properties. Valence is more positive with lower spectral slopes, a greater emergence of strong partials, and an amplitude envelope with a sharper attack and earlier decay. Higher tension arousal is carried by brighter sounds

Close-loop Dynamic Stall Control on a Pitching Airfoil

Science.gov (United States)

Giles, Ian; Corke, Thomas

2017-11-01

A closed-loop control scheme utilizing a plasma actuator to control dynamic stall is presented. The plasma actuator is located at the leading-edge of a pitching airfoil. It initially pulses at an unsteady frequency that perturbs the boundary layer flow over the suction surface of the airfoil. As the airfoil approaches and enters stall, the amplification of the unsteady disturbance is detected by an onboard pressure sensor also located near the leading edge. Once detected, the actuator is switched to a higher voltage control state that in static airfoil experiments would reattach the flow. The threshold level of the detection is a parameter in the control scheme. Three stall regimes were examined: light, medium, and deep stall, that were defined by their stall penetration angles. The results showed that in general, the closed-loop control scheme was effective at controlling dynamic stall. The cycle-integrated lift improved in all cases, and increased by as much as 15% at the lowest stall penetration angle. As important, the cycle-integrated aerodynamic damping coefficient also increased in all cases, and was made to be positive at the light stall regime where it traditionally is negative. The latter is important in applications where negative damping can lead to stall flutter.

Singing ability is rooted in vocal-motor control of pitch.

Science.gov (United States)

Hutchins, Sean; Larrouy-Maestri, Pauline; Peretz, Isabelle

2014-11-01

The inability to vocally match a pitch can be caused by poor pitch perception or by poor vocal-motor control. Although previous studies have tried to examine the relationship between pitch perception and vocal production, they have failed to control for the timbre of the target to be matched. In the present study, we compare pitch-matching accuracy with an unfamiliar instrument (the slider) and with the voice, designed such that the slider plays back recordings of the participant's own voice. We also measured pitch accuracy in singing a familiar melody ("Happy Birthday") to assess the relationship between single-pitch-matching tasks and melodic singing. Our results showed that participants (all nonmusicians) were significantly better at matching recordings of their own voices with the slider than with their voice, indicating that vocal-motor control is an important limiting factor on singing ability. We also found significant correlations between the ability to sing a melody in tune and vocal pitch matching, but not pitch matching on the slider. Better melodic singers also tended to have higher quality voices (as measured by acoustic variables). These results provide important evidence about the role of vocal-motor control in poor singing ability and demonstrate that single-pitch-matching tasks can be useful in measuring general singing abilities.

Pitch Sequence Complexity and Long-Term Pitcher Performance

Directory of Open Access Journals (Sweden)

Joel R. Bock

2015-03-01

Full Text Available Winning one or two games during a Major League Baseball (MLB season is often the difference between a team advancing to post-season play, or “waiting until next year”. Technology advances have made it feasible to augment historical data with in-game contextual data to provide managers immediate insights regarding an opponent’s next move, thereby providing a competitive edge. We developed statistical models of pitcher behavior using pitch sequences thrown during three recent MLB seasons (2011–2013. The purpose of these models was to predict the next pitch type, for each pitcher, based on data available at the immediate moment, in each at-bat. Independent models were developed for each player’s most frequent four pitches. The overall predictability of next pitch type is 74:5%. Additional analyses on pitcher predictability within specific game situations are discussed. Finally, using linear regression analysis, we show that an index of pitch sequence predictability may be used to project player performance in terms of Earned Run Average (ERA and Fielding Independent Pitching (FIP over a longer term. On a restricted range of the independent variable, reducing complexity in selection of pitches is correlated with higher values of both FIP and ERA for the players represented in the sample. Both models were significant at the α = 0.05 level (ERA: p = 0.022; FIP: p = 0.0114. With further development, such models may reduce risk faced by management in evaluation of potential trades, or to scouts assessing unproven emerging talent. Pitchers themselves might benefit from awareness of their individual statistical tendencies, and adapt their behavior on the mound accordingly. To our knowledge, the predictive model relating pitch-wise complexity and long-term performance appears to be novel.

RBF neural network based PI pitch controller for a class of 5-MW wind turbines using particle swarm optimization algorithm.

Science.gov (United States)

Poultangari, Iman; Shahnazi, Reza; Sheikhan, Mansour

2012-09-01

In order to control the pitch angle of blades in wind turbines, commonly the proportional and integral (PI) controller due to its simplicity and industrial usability is employed. The neural networks and evolutionary algorithms are tools that provide a suitable ground to determine the optimal PI gains. In this paper, a radial basis function (RBF) neural network based PI controller is proposed for collective pitch control (CPC) of a 5-MW wind turbine. In order to provide an optimal dataset to train the RBF neural network, particle swarm optimization (PSO) evolutionary algorithm is used. The proposed method does not need the complexities, nonlinearities and uncertainties of the system under control. The simulation results show that the proposed controller has satisfactory performance. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Fine-grained pitch processing of music and speech in congenital amusia.

Science.gov (United States)

Tillmann, Barbara; Rusconi, Elena; Traube, Caroline; Butterworth, Brian; Umiltà, Carlo; Peretz, Isabelle

2011-12-01

Congenital amusia is a lifelong disorder of music processing that has been ascribed to impaired pitch perception and memory. The present study tested a large group of amusics (n=17) and provided evidence that their pitch deficit affects pitch processing in speech to a lesser extent: Fine-grained pitch discrimination was better in spoken syllables than in acoustically matched tones. Unlike amusics, control participants performed fine-grained pitch discrimination better for musical material than for verbal material. These findings suggest that pitch extraction can be influenced by the nature of the material (music vs speech), and that amusics' pitch deficit is not restricted to musical material, but extends to segmented speech events. © 2011 Acoustical Society of America

The Effects of Lexical Pitch Accent on Infant Word Recognition in Japanese

Directory of Open Access Journals (Sweden)

Mitsuhiko Ota

2018-01-01

Full Text Available Learners of lexical tone languages (e.g., Mandarin develop sensitivity to tonal contrasts and recognize pitch-matched, but not pitch-mismatched, familiar words by 11 months. Learners of non-tone languages (e.g., English also show a tendency to treat pitch patterns as lexically contrastive up to about 18 months. In this study, we examined if this early-developing capacity to lexically encode pitch variations enables infants to acquire a pitch accent system, in which pitch-based lexical contrasts are obscured by the interaction of lexical and non-lexical (i.e., intonational features. Eighteen 17-month-olds learning Tokyo Japanese were tested on their recognition of familiar words with the expected pitch or the lexically opposite pitch pattern. In early trials, infants were faster in shifting their eyegaze from the distractor object to the target object than in shifting from the target to distractor in the pitch-matched condition. In later trials, however, infants showed faster distractor-to-target than target-to-distractor shifts in both the pitch-matched and pitch-mismatched conditions. We interpret these results to mean that, in a pitch-accent system, the ability to use pitch variations to recognize words is still in a nascent state at 17 months.

Perception of words and pitch patterns in song and speech

Directory of Open Access Journals (Sweden)

Julia eMerrill

2012-03-01

Full Text Available This fMRI study examines shared and distinct cortical areas involved in the auditory perception of song and speech at the level of their underlying constituents: words, pitch and rhythm. Univariate and multivariate analyses were performed on the brain activity patterns of six conditions, arranged in a subtractive hierarchy: sung sentences including words, pitch and rhythm; hummed speech prosody and song melody containing only pitch patterns and rhythm; as well as the pure musical or speech rhythm.Systematic contrasts between these balanced conditions following their hierarchical organization showed a great overlap between song and speech at all levels in the bilateral temporal lobe, but suggested a differential role of the inferior frontal gyrus (IFG and intraparietal sulcus (IPS in processing song and speech. The left IFG was involved in word- and pitch-related processing in speech, the right IFG in processing pitch in song.Furthermore, the IPS showed sensitivity to discrete pitch relations in song as opposed to the gliding pitch in speech. Finally, the superior temporal gyrus and premotor cortex coded for general differences between words and pitch patterns, irrespective of whether they were sung or spoken. Thus, song and speech share many features which are reflected in a fundamental similarity of brain areas involved in their perception. However, fine-grained acoustic differences on word and pitch level are reflected in the activity of IFG and IPS.

Kinematics changes in technique of a softball pitch

OpenAIRE

Tomášek, Petr

2007-01-01

Headline: Kinematic changes in technique of a softball pitch. Aims of thesis: I will compare the pitches ofprofessinal european softball wonam pitchers and then I will compare their technique with professional czech woman pitcher. Methods: Results: Key words: For examination of different techniques, I choosed thease professinal european softball wonam pitchers 3 Italians and 2 Greeks. Videotape was taken on European championship 2005 in Prague. For description of softball pitch I used a metho...

Magnetospheric particle detection efficiency of a conical telescope

International Nuclear Information System (INIS)

Miah, M.A.; Mitchell, J.W.; Wefel, J.P.

1989-01-01

A semianalytic program has been developed to map the pitch angles of magnetospheric particles onto a detector telescope acceptance cone. The telescope fractional efficiency is defined as the fraction of the pitch angle cone in common with the telescope cone multiplied by the fractional perpendicular component of the exposed detector area, and normalized by 2π. Calculations have been performed as a function of the satellite's location, orbital inclination and the zenith angle of the telescope axis, both in dipole and real geomagnetic field models. At the dipole equator, the peak efficiency occurs at 90 0 pitch angle. In the real geomagnetic field model, the average value of the pitch angle for maximum efficiency is ≅ 88 0 . The efficiency function depends strongly upon latitude and is independent of longitude in a dipole field, but depends on longitude in the real field model. In either field model, altitude, angle of tilt and orbital inclination have little effect upon efficiency. The efficiency function calculated at the dipole equator can be used at the minimum magnetic field equator with little error, but not for points away from the B min position. The results are applied to calculate the absolute flux of magnetospheric particles observed near the equator. (orig.)

Effects of Music and Tonal Language Experience on Relative Pitch Performance.

Science.gov (United States)

Ngo, Mary Kim; Vu, Kim-Phuong L; Strybel, Thomas Z

2016-01-01

We examined the interaction between music and tone language experience as related to relative pitch processing by having participants judge the direction and magnitude of pitch changes in a relative pitch task. Participants' performance on this relative pitch task was assessed using the Cochran-Weiss-Shanteau (CWS) index of expertise, based on a ratio of discrimination over consistency in participants' relative pitch judgments. Testing took place in 2 separate sessions on different days to assess the effects of practice on participants' performance. Participants also completed the Montreal Battery of Evaluation of Amusia (MBEA), an existing measure comprising subtests aimed at evaluating relative pitch processing abilities. Musicians outperformed nonmusicians on both the relative pitch task, as measured by the CWS index, and the MBEA, but tonal language speakers outperformed non-tonal language speakers only on the MBEA. A closer look at the discrimination and consistency component scores of the CWS index revealed that musicians were better at discriminating different pitches and more consistent in their assessments of the direction and magnitude of relative pitch change.

Tune That Beer! Listening for the Pitch of Beer

Directory of Open Access Journals (Sweden)

Felipe Reinoso Carvalho

2016-11-01

Full Text Available We report two experiments designed to assess the key sensory drivers underlying people’s association of a specific auditory pitch with Belgian beer. In particular, we assessed if people would rely mostly on the differences between beers in terms of their relative alcohol strength, or on the contrast between the most salient taste attributes of the different beers. In Experiment 1, the participants rated three bitter beers (differing in alcohol content, using a narrow range of pitch choices (50–500 Hz. The results revealed that the beers were all rated around the same pitch (Mean = 232 Hz, SD = 136 Hz. In Experiment 2, a wider range of pitch choices (50–1500 Hz, along with the addition of a much sweeter beer, revealed that people mostly tend to match beers with bitter-range profiles at significantly lower pitch ranges when compared to the average pitch of a much sweeter beer. These results therefore demonstrate that clear differences in taste attributes lead to distinctly different matches in terms of pitch. Having demonstrated the robustness of the basic crossmodal matching, future research should aim to uncover the basis for such matches and better understand the perceptual effects of matching/non-matching tones on the multisensory drinking experience.

Relating the absence of binaural pitch percept to retro-cochlear impairment

DEFF Research Database (Denmark)

Santurette, Sébastien; Dau, Torsten

Binaural pitch stimuli, created by introducing an interaural phase difference over a narrow band of otherwise diotic white noise, produce an immediate tonal sensation with a pitch close to the centre of the phase-shifted band. In Santurette and Dau [Hear. Res. 223(1-2):29-47, 2007], it was shown...... that the salience of binaural pitch was affected by hearing impairment. Specifically, for subjects with a sensorineural impairment, binaural pitch perception was weaker than the normal-hearing average but the pitch sensation was immediately present. In contrast, no binaural pitch sensation at all was found...... for the (only) two subjects with damage at central stages. The aim of the present study is to clarify whether such a sharp distinction between levels of impairment can be made using binaural pitch stimuli. A pitch detection test was performed by three groups of subjects with: 1) normal hearing; 2) a cochlear...

Relationship of radiation dose and spiral pitch for multi-slice CT system

International Nuclear Information System (INIS)

Song Shaojuan; Wang Wei; Liu Chuanya

2006-01-01

Objective: To study the relations of radiation dose and spiral pitch for multi-slice CT system. Methods: 16 mm dose phantom with solidose 300/400 pen-style ion chamber inserted into each of five holes in turn was scanned with different spiral pitch by LightSpeed 16-slice CT and Sensation 16-slice and 64-slice CT and radiation dose. Results: CTDI vol of axial scan and spiral scan for the three types of CT system are: (1) LightSpeed 16-slice CT: 28.9 (axial), 51.4 (pitch 0.562), 30.8 (pitch 0.938) and 16.5 ( pitch 1.75 ); (2) Sensation 16-slice CT: 41.2(axial) and 40.3(pitch 0.5) ,41.5(pitch 1) and 43.2(pitch 1.5); (3) Sensation 64- slice CT: 41.2(axial) and 40.3(pitch 0.5),41.5(pitch 1),43.2(pitch 1.5). Conclusions: For LightSpeed 16-slice CT, the measured radiation dose decreased with the increase of spiral pitch, the image quality could keep constant only if we increase mAs. While for Sensation 16-slice and 64-slice CT system, the measured radiation dose was identical for different pitch, and the image quality was identical because of the use of mAs auto control technique The mAs should be adjusted in different way according to the type of CT system when the pitch is changed in daily operation. (authors)

Multi-pitch Estimation using Semidefinite Programming

DEFF Research Database (Denmark)

Jensen, Tobias Lindstrøm; Vandenberghe, Lieven

2017-01-01

assuming a Nyquist sampled signal by adding an additional semidefinite constraint. We show that the proposed estimator has superior performance compared to state- of-the-art methods for separating two closely spaced fundamentals and approximately achieves the asymptotic Cramér-Rao lower bound.......Multi-pitch estimation concerns the problem of estimating the fundamental frequencies (pitches) and amplitudes/phases of multiple superimposed harmonic signals with application in music, speech, vibration analysis etc. In this paper we formulate a complex-valued multi-pitch estimator via...... a semidefinite programming representation of an atomic decomposition over a continuous dictionary of complex exponentials and extend this to real-valued data via a real semidefinite pro-ram with the same dimensions (i.e. half the size). We further impose a continuous frequency constraint naturally occurring from...

ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES

International Nuclear Information System (INIS)

ROSER, T.; AHRENS, L.; BAI, M.

2004-01-01

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction

Low-energy ion distribution functions on a magnetically quiet day at geostationary altitude (L = 7)

International Nuclear Information System (INIS)

Singh, N.; Raitt, W.J.; Yasuhara, F.

1982-01-01

By using averaged data from ATS 6, ion energy and pitch angle distribution functions were examined for a magnetically quiet day (July 18, 1974). The data showed that for both field-aligned and perpendicular fluxes, the population had a mixture of characteristic energies. It was found that over three different energy bands in the range 3-600 eV the distribution functions could be fairly well approximated by Maxwellian distributions with temperatures in the ranges 3-10 eV, 30-50 eV, and approximately 70 eV in energy bands of 3-30 eV, 30-140 eV, and 140-600 eV, respectively. Pitch angle distributions were found to vary the local time; strong field-aligned particle fluxes were measured in the midnight and afternoon sectors, minor field-aligned components persisted to some extent at all times, especially at low energies (E 0 was seen. By using the assumption that the plasma was corotating with the satellite, we have examined pitch angle scattering mechanisms responsible for the observed transformation of pitch angle distribution. It was found that a magnetic noise of power spectral density b 2 -3 γ 2 /Hz belonging to electromagnetic ion cyclotron mode (L mode) near the ion cyclotron frequency could be very effective in trapping the field-aligned fluxes by pitch angle scattering

Optimal pitching axis location of flapping wings for efficient hovering flight.

Science.gov (United States)

Wang, Q; Goosen, J F L; van Keulen, F

2017-09-01

Flapping wings can pitch passively about their pitching axes due to their flexibility, inertia, and aerodynamic loads. A shift in the pitching axis location can dynamically alter the aerodynamic loads, which in turn changes the passive pitching motion and the flight efficiency. Therefore, it is of great interest to investigate the optimal pitching axis for flapping wings to maximize the power efficiency during hovering flight. In this study, flapping wings are modeled as rigid plates with non-uniform mass distribution. The wing flexibility is represented by a linearly torsional spring at the wing root. A predictive quasi-steady aerodynamic model is used to evaluate the lift generated by such wings. Two extreme power consumption scenarios are modeled for hovering flight, i.e. the power consumed by a drive system with and without the capacity of kinetic energy recovery. For wings with different shapes, the optimal pitching axis location is found such that the cycle-averaged power consumption during hovering flight is minimized. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to traditional wings used by most of flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. With the optimized pitching axis, flapping wings show higher pitching amplitudes and start the pitching reversals in advance of the sweeping reversals. These phenomena lead to higher lift-to-drag ratios and, thus, explain the lower power consumption. In addition, the optimized pitching axis provides the drive system higher potential to recycle energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when

Long-term memory for pitch in six-month-old infants.

Science.gov (United States)

Plantinga, Judy; Trainor, Laurel J

2003-11-01

We examined 6-month-old infants' long-term memory representations for the pitch of familiar melodies. Infants remembered the relative pitch of the melodies, but the absolute pitch was either not remembered or not a particularly salient attribute.

Angle-specific transparent conducting electrodes with metallic gratings

Energy Technology Data Exchange (ETDEWEB)

Rivolta, N. X. A., E-mail: nicolas.rivolta@umons.ac.be; Maes, B. [Micro- and Nanophotonic Materials Group, Faculty of Science, University of Mons, Avenue Maistriau 19, B-7000 Mons (Belgium)

2014-08-07

Transparent conducting electrodes, which are not made from indium tin oxide, and which display a strong angular dependence are useful for various technologies. Here, we introduce a tilted silver grating that combines a large conductance with a strong and angle-specific transmittance. When the light incidence angle matches the tilt angle of the grating, transmittance is close to the maximum along a very broadband range. We explain the behavior through simulations that show in detail the plasmonic and interference effects at play.

An investigation of spatial representation of pitch in individuals with congenital amusia.

Science.gov (United States)

Lu, Xuejing; Sun, Yanan; Thompson, William Forde

2017-09-01

Spatial representation of pitch plays a central role in auditory processing. However, it is unknown whether impaired auditory processing is associated with impaired pitch-space mapping. Experiment 1 examined spatial representation of pitch in individuals with congenital amusia using a stimulus-response compatibility (SRC) task. For amusic and non-amusic participants, pitch classification was faster and more accurate when correct responses involved a physical action that was spatially congruent with the pitch height of the stimulus than when it was incongruent. However, this spatial representation of pitch was not as stable in amusic individuals, revealed by slower response times when compared with control individuals. One explanation is that the SRC effect in amusics reflects a linguistic association, requiring additional time to link pitch height and spatial location. To test this possibility, Experiment 2 employed a colour-classification task. Participants judged colour while ignoring a concurrent pitch by pressing one of two response keys positioned vertically to be congruent or incongruent with the pitch. The association between pitch and space was found in both groups, with comparable response times in the two groups, suggesting that amusic individuals are only slower to respond to tasks involving explicit judgments of pitch.

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

Energy Technology Data Exchange (ETDEWEB)

Sissay, Adonay [Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Lopata, Kenneth, E-mail: klopata@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

2016-09-07

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

International Nuclear Information System (INIS)

Sissay, Adonay; Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J.; Lopata, Kenneth

2016-01-01

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

Selective attention to sound location or pitch studied with fMRI.

Science.gov (United States)

Degerman, Alexander; Rinne, Teemu; Salmi, Juha; Salonen, Oili; Alho, Kimmo

2006-03-10

We used 3-T functional magnetic resonance imaging to compare the brain mechanisms underlying selective attention to sound location and pitch. In different tasks, the subjects (N = 10) attended to a designated sound location or pitch or to pictures presented on the screen. In the Attend Location conditions, the sound location varied randomly (left or right), while the pitch was kept constant (high or low). In the Attend Pitch conditions, sounds of randomly varying pitch (high or low) were presented at a constant location (left or right). Both attention to location and attention to pitch produced enhanced activity (in comparison with activation caused by the same sounds when attention was focused on the pictures) in widespread areas of the superior temporal cortex. Attention to either sound feature also activated prefrontal and inferior parietal cortical regions. These activations were stronger during attention to location than during attention to pitch. Attention to location but not to pitch produced a significant increase of activation in the premotor/supplementary motor cortices of both hemispheres and in the right prefrontal cortex, while no area showed activity specifically related to attention to pitch. The present results suggest some differences in the attentional selection of sounds on the basis of their location and pitch consistent with the suggested auditory "what" and "where" processing streams.

A Computationally Efficient Method for Polyphonic Pitch Estimation

Directory of Open Access Journals (Sweden)

Ruohua Zhou

2009-01-01

Full Text Available This paper presents a computationally efficient method for polyphonic pitch estimation. The method employs the Fast Resonator Time-Frequency Image (RTFI as the basic time-frequency analysis tool. The approach is composed of two main stages. First, a preliminary pitch estimation is obtained by means of a simple peak-picking procedure in the pitch energy spectrum. Such spectrum is calculated from the original RTFI energy spectrum according to harmonic grouping principles. Then the incorrect estimations are removed according to spectral irregularity and knowledge of the harmonic structures of the music notes played on commonly used music instruments. The new approach is compared with a variety of other frame-based polyphonic pitch estimation methods, and results demonstrate the high performance and computational efficiency of the approach.

Subcortical plasticity following perceptual learning in a pitch discrimination task

OpenAIRE

Carcagno, Samuele; Plack, Christopher J.

2011-01-01

Practice can lead to dramatic improvements in the discrimination of auditory stimuli. In this study, we investigated changes of the frequency-following response (FFR), a subcortical component of the auditory evoked potentials, after a period of pitch discrimination training. Twenty-seven adult listeners were trained for 10 h on a pitch discrimination task using one of three different complex tone stimuli. One had a static pitch contour, one had a rising pitch contour, and one had a falling pi...

Illusory conjunctions of pitch and duration in unfamiliar tone sequences.

Science.gov (United States)

Thompson, W F; Hall, M D; Pressing, J

2001-02-01

In 3 experiments, the authors examined short-term memory for pitch and duration in unfamiliar tone sequences. Participants were presented a target sequence consisting of 2 tones (Experiment 1) or 7 tones (Experiments 2 and 3) and then a probe tone. Participants indicated whether the probe tone matched 1 of the target tones in both pitch and duration. Error rates were relatively low if the probe tone matched 1 of the target tones or if it differed from target tones in pitch, duration, or both. Error rates were remarkably high, however, if the probe tone combined the pitch of 1 target tone with the duration of a different target tone. The results suggest that illusory conjunctions of these dimensions frequently occur. A mathematical model is presented that accounts for the relative contribution of pitch errors, duration errors, and illusory conjunctions of pitch and duration.

Two LQRI based Blade Pitch Controls for Wind Turbines

Directory of Open Access Journals (Sweden)

Yoonsu Nam

2012-06-01

Full Text Available As the wind turbine size has been increasing and their mechanical components are built lighter, the reduction of the structural loads becomes a very important task of wind turbine control in addition to maximum wind power capture. In this paper, we present a separate set of collective and individual pitch control algorithms. Both pitch control algorithms use the LQR control technique with integral action (LQRI, and utilize Kalman filters to estimate system states and wind speed. Compared to previous works in this area, our pitch control algorithms can control rotor speed and blade bending moments at the same time to improve the trade-off between rotor speed regulation and load reduction, while both collective and individual pitch controls can be designed separately. Simulation results show that the proposed collective and individual pitch controllers achieve very good rotor speed regulation and significant reduction of blade bending moments.

Children’s identification of familiar songs from pitch and timing cues

Directory of Open Access Journals (Sweden)

Anna eVolkova

2014-08-01

Full Text Available The goal of the present study was to ascertain whether children with normal hearing and prelingually deaf children with cochlear implants could use pitch or timing cues alone or in combination to identify familiar songs. Children 4-7 years of age were required to identify the theme songs of familiar TV shows in a simple task with excerpts that preserved (1 the relative pitch and timing cues of the melody but not the original instrumentation, (2 the timing cues only (rhythm, meter, and tempo, and (3 the relative pitch cues only (pitch contour and intervals. Children with normal hearing performed at high levels and comparably across the three conditions. The performance of child implant users was well above chance levels when both pitch and timing cues were available, marginally above chance with timing cues only, and at chance with pitch cues only. This is the first demonstration that children can identify familiar songs from monotonic versions—timing cues but no pitch cues—and from isochronous versions—pitch cues but no timing cues. The study also indicates that, in the context of a very simple task, young implant users readily identify songs from melodic versions that preserve pitch and timing cues.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers.

Science.gov (United States)

Liu, Fang; Chan, Alice H D; Ciocca, Valter; Roquet, Catherine; Peretz, Isabelle; Wong, Patrick C M

2016-07-01

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

A new generation of small pixel pitch/SWaP cooled infrared detectors

Science.gov (United States)

Espuno, L.; Pacaud, O.; Reibel, Y.; Rubaldo, L.; Kerlain, A.; Péré-Laperne, N.; Dariel, A.; Roumegoux, J.; Brunner, A.; Kessler, A.; Gravrand, O.; Castelein, P.

2015-10-01

Following clear technological trends, the cooled IR detectors market is now in demand for smaller, more efficient and higher performance products. This demand pushes products developments towards constant innovations on detectors, read-out circuits, proximity electronics boards, and coolers. Sofradir was first to show a 10μm focal plane array (FPA) at DSS 2012, and announced the DAPHNIS 10μm product line back in 2014. This pixel pitch is a key enabler for infrared detectors with increased resolution. Sofradir recently achieved outstanding products demonstrations at this pixel pitch, which clearly demonstrate the benefits of adopting 10μm pixel pitch focal plane array-based detectors. Both HD and XGA Daphnis 10μm products also benefit from a global video datapath efficiency improvement by transitioning to digital video interfaces. Moreover, innovative smart pixels functionalities drastically increase product versatility. In addition to this strong push towards a higher pixels density, Sofradir acknowledges the need for smaller and lower power cooled infrared detector. Together with straightforward system interfaces and better overall performances, latest technological advances on SWAP-C (Size, Weight, Power and Cost) Sofradir products enable the advent of a new generation of high performance portable and agile systems (handheld thermal imagers, unmanned aerial vehicles, light gimbals etc...). This paper focuses on those features and performances that can make an actual difference in the field.

Pitch and time, tonality and meter: how do musical dimensions combine?

Science.gov (United States)

Prince, Jon B; Thompson, William F; Schmuckler, Mark A

2009-10-01

The authors examined how the structural attributes of tonality and meter influence musical pitch-time relations. Listeners heard a musical context followed by probe events that varied in pitch class and temporal position. Tonal and metric hierarchies contributed additively to the goodness-of-fit of probes, with pitch class exerting a stronger influence than temporal position (Experiment 1), even when listeners attempted to ignore pitch (Experiment 2). Speeded classification tasks confirmed this asymmetry. Temporal classification was biased by tonal stability (Experiment 3), but pitch classification was unaffected by temporal position (Experiment 4). Experiments 5 and 6 ruled out explanations based on the presence of pitch classes and temporal positions in the context, unequal stimulus quantity, and discriminability. The authors discuss how typical Western music biases attention toward pitch and distinguish between dimensional discriminability and salience. PsycINFO Database Record (c) 2009 APA, all rights reserved.

Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

Science.gov (United States)

Taylor, Stuart A; Halligan, Steve; Bartram, Clive I; Morgan, Paul R; Talbot, Ian C; Fry, Nicola; Saunders, Brian P; Khosraviani, Kirosh; Atkin, Wendy

2003-10-01

To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon. Copyright RSNA, 2003

Investors prefer entrepreneurial ventures pitched by attractive men.

Science.gov (United States)

Brooks, Alison Wood; Huang, Laura; Kearney, Sarah Wood; Murray, Fiona E

2014-03-25

Entrepreneurship is a central path to job creation, economic growth, and prosperity. In the earliest stages of start-up business creation, the matching of entrepreneurial ventures to investors is critically important. The entrepreneur's business proposition and previous experience are regarded as the main criteria for investment decisions. Our research, however, documents other critical criteria that investors use to make these decisions: the gender and physical attractiveness of the entrepreneurs themselves. Across a field setting (three entrepreneurial pitch competitions in the United States) and two experiments, we identify a profound and consistent gender gap in entrepreneur persuasiveness. Investors prefer pitches presented by male entrepreneurs compared with pitches made by female entrepreneurs, even when the content of the pitch is the same. This effect is moderated by male physical attractiveness: attractive males were particularly persuasive, whereas physical attractiveness did not matter among female entrepreneurs.

Proportional resonant individual pitch control for mitigation of wind turbines loads

DEFF Research Database (Denmark)

Zhang, Yunqian; Chen, Zhe; Cheng, Ming

2013-01-01

attenuation. The individual pitch control (IPC) is a promising way to reduce the wind turbine loads. This study presents a proportional resonant (PR) IPC, which does not need the measurement of blade azimuth angle and multiple complex Coleman transformations between rotational coordinate frame and stationary...... coordinate frame. The new strategy can attenuate the 1p and higher harmonics on the wind turbine blades as well as 3p on the hub without any filters. The wind turbine code fatigue, aerodynamics, structures and turbulence is applied to a doubly fed induction generator-based wind power generation system....... The simulations are performed on the National Renewable Energy Laboratory 1.5 MW upwind reference wind turbine model. The simulation results are presented and discussed to demonstrate the capability and effectiveness of the proposed PR IPC method....

Model of alpha particle diffusion in the outer limiter shadow of TFTR

International Nuclear Information System (INIS)

Wang, S.; Academia Sinica, Hefei, Anhui; Zweben, S.J.

1996-05-01

A new code, Monte Carlo Collisional Stochastic Orbit Retracing (MCCSOR), has been developed to model the alpha particle loss signal as measured by the outer midplane scintillator detector in TFTR. The shadowing effects due to the outer limiters and the detector itself have been included, along with a pitch angle scattering and stochastic ripple diffusion. Shadowing by the outer limiters has a strong effect on both the magnitude and pitch angle distribution of the calculated loss. There is at least qualitative agreement between the calculated results and the experimental data

On the use of mesophase pitch for the preparation of hierarchical porous carbon monoliths by nanocasting

Directory of Open Access Journals (Sweden)

Philipp Adelhelm, Karin Cabrera and Bernd M Smarsly

2012-01-01

Full Text Available A detailed study is given on the synthesis of a hierarchical porous carbon, possessing both meso- and macropores, using a mesophase pitch (MP as the carbon precursor. This carbon material is prepared by the nanocasting approach involving the replication of a porous silica monolith (hard templating. While this carbon material has already been tested in energy storage applications, various detailed aspects of its formation and structure are addressed in this study. Scanning electron microscopy (SEM, Hg porosimetry and N2 physisorption are used to characterize the morphology and porosity of the carbon replica. A novel approach for the detailed analysis of wide-angle x-ray scattering (WAXS from non-graphitic carbons is applied to quantitatively compare the graphene microstructures of carbons prepared using MP and furfuryl alcohol (FA. This WAXS analysis underlines the importance of the carbon precursor in the synthesis of templated porous carbon materials via the nanocasting route. Our study demonstrates that a mesophase pitch is a superior precursor whenever a high-purity, low-micropore-content and well-developed graphene structure is desired.

DIAGNOSIS OF PITCH AND LOAD DEFECTS

DEFF Research Database (Denmark)

2009-01-01

The invention relates to a method, system and computer readable code for diagnosis of pitch and/or load defects of e.g. wind turbines as well as wind turbines using said diagnosis method and/or comprising said diagnosis system.......The invention relates to a method, system and computer readable code for diagnosis of pitch and/or load defects of e.g. wind turbines as well as wind turbines using said diagnosis method and/or comprising said diagnosis system....

The depletion properties of silicon microstrip detectors with variable strip pitch

International Nuclear Information System (INIS)

Krizmanic, J.F.

1994-01-01

We have investigated the depletion properties of trapezoidal shaped silicon microstrip detectors which have variable strip pitch. Four types of detectors were examined: three detectors have constant strip width and a fourth has a varying strip width. The detectors are single sided with readout performed via p + strips. The depletion properties of the devices were measured using two different methods. The first used capacitance versus voltage measurements, while the second used a 1060 nm wavelength laser coupled to a single mode fiber with a mode field diameter less than 10 μm. The small laser spot size allowed for the depletion depth to be measured in a localized area of the detector. The laser induced charge on an electrode was measured as a function of reverse bias voltage using a sensitive charge preamplifier. The depletion voltages of the detectors demonstrate a strong dependence upon the ratio of strip width to strip pitch. Moreover, these measurements show that a large value of this ratio yields a lower depletion voltage and vice versa. (orig.)

Shoulder and Scapular Kinematics during the Windmill Softball Pitch

OpenAIRE

Backus, Sherry I.; Kraszewski, Andrew; Kontaxis, Andreas; Gibbons, Mandi; Bido, Jennifer; Graziano, Jessica; Hafer, Jocelyn; Jones, Kristofer J.; Hillstrom, Howard; Fealy, Stephen

2013-01-01

Objectives: Pitch count has been studied extensively in the overhand throwing athlete. However, pitch count and fatigue have not been systematically evaluated in the female windmill (underhand) throwing athlete. Direct kinematic measurements of the glenohumeral and scapulo-thoracic joint have not to be correlated and determined. The purpose is to measure scapular kinematics for the high school female windmill softball pitcher and identify kinematic adaptions and changes in pitching performanc...

Politeness, emotion, and gender: A sociophonetic study of voice pitch modulation

Science.gov (United States)

Yuasa, Ikuko

The present dissertation is a cross-gender and cross-cultural sociophonetic exploration of voice pitch characteristics utilizing speech data derived from Japanese and American speakers in natural conversations. The roles of voice pitch modulation in terms of the concepts of politeness and emotion as they pertain to culture and gender will be investigated herein. The research interprets the significance of my findings based on the acoustic measurements of speech data as they are presented in the ERB-rate scale (the most appropriate scale for human speech perception). The investigation reveals that pitch range modulation displayed by Japanese informants in two types of conversations is closely linked to types of politeness adopted by those informants. The degree of the informants' emotional involvement and expressions reflected in differing pitch range widths plays an important role in determining the relationship between pitch range modulation and politeness. The study further correlates the Japanese cultural concept of enryo ("self-restraint") with this phenomenon. When median values were examined, male and female pitch ranges across cultures did not conspicuously differ. However, sporadically occurring women's pitch characteristics which culturally differ in width and height of pitch ranges may create an 'emotional' perception of women's speech style. The salience of these pitch characteristics appears to be the source of the stereotypically linked sound of women's speech being identified as 'swoopy' or 'shrill' and thus 'emotional'. Such women's salient voice characteristics are interpreted in light of camaraderie/positive politeness. Women's use of conspicuous paralinguistic features helps to create an atmosphere of camaraderie. These voice pitch characteristics promote the establishment of a sense of camaraderie since they act to emphasize such feelings as concern, support, and comfort towards addressees, Moreover, men's wide pitch ranges are discussed in view

Anomalous capillary flow of coal tar pitches

Energy Technology Data Exchange (ETDEWEB)

Saint Romain, J.L.; Lahaye, J.; Ehrburger, P.; Couderc, P.

1986-06-01

Capillary flow of liquid coal tar pitch into a coke bed was studied. Anomalies in the flow could not be attributed to a plugging effect for mesophase content lower than 20 wt%. The flow behaviour of small pitch droplets can be correlated with the change in physicochemical properties, as measured by the glass transition temperature, on penetration into the coke bed. 4 references.

Detection and identification of monaural and binaural pitch contours in dyslexic listeners

DEFF Research Database (Denmark)

Santurette, Sébastien; Dau, Torsten; Poelmans, Hanne

2010-01-01

found that a majority of dyslexic subjects were unable to hear binaural pitch, the latter obtained a clear response of dyslexic listeners to Huggins’ pitch (HP) (Cramer and Huggins, 1958). The present study clarified whether impaired binaural pitch perception is found in dyslexia. Results from a pitch...

Neural mechanisms underlying melodic perception and memory for pitch.

Science.gov (United States)

Zatorre, R J; Evans, A C; Meyer, E

1994-04-01

The neural correlates of music perception were studied by measuring cerebral blood flow (CBF) changes with positron emission tomography (PET). Twelve volunteers were scanned using the bolus water method under four separate conditions: (1) listening to a sequence of noise bursts, (2) listening to unfamiliar tonal melodies, (3) comparing the pitch of the first two notes of the same set of melodies, and (4) comparing the pitch of the first and last notes of the melodies. The latter two conditions were designed to investigate short-term pitch retention under low or high memory load, respectively. Subtraction of the obtained PET images, superimposed on matched MRI scans, provides anatomical localization of CBF changes associated with specific cognitive functions. Listening to melodies, relative to acoustically matched noise sequences, resulted in CBF increases in the right superior temporal and right occipital cortices. Pitch judgments of the first two notes of each melody, relative to passive listening to the same stimuli, resulted in right frontal-lobe activation. Analysis of the high memory load condition relative to passive listening revealed the participation of a number of cortical and subcortical regions, notably in the right frontal and right temporal lobes, as well as in parietal and insular cortex. Both pitch judgment conditions also revealed CBF decreases within the left primary auditory cortex. We conclude that specialized neural systems in the right superior temporal cortex participate in perceptual analysis of melodies; pitch comparisons are effected via a neural network that includes right prefrontal cortex, but active retention of pitch involves the interaction of right temporal and frontal cortices.

Absolute pitch: a case study.

Science.gov (United States)

Vernon, P E

1977-11-01

The auditory skill known as 'absolute pitch' is discussed, and it is shown that this differs greatly in accuracy of identification or reproduction of musical tones from ordinary discrimination of 'tonal height' which is to some extent trainable. The present writer possessed absolute pitch for almost any tone or chord over the normal musical range, from about the age of 17 to 52. He then started to hear all music one semitone too high, and now at the age of 71 it is heard a full tone above the true pitch. Tests were carried out under controlled conditions, in which 68 to 95 per cent of notes were identified as one semitone or one tone higher than they should be. Changes with ageing seem more likely to occur in the elasticity of the basilar membrane mechanisms than in the long-term memory which is used for aural analysis of complex sounds. Thus this experience supports the view that some resolution of complex sounds takes place at the peripheral sense organ, and this provides information which can be incorrect, for interpretation by the cortical centres.

The intensity-pitch relation revisited: monopolar versus bipolar cochlear stimulation.

Science.gov (United States)

Arnoldner, Christoph; Riss, Dominik; Kaider, Alexandra; Mair, Alois; Wagenblast, Jens; Baumgartner, Wolf-Dieter; Gstöttner, Wolfgang; Hamzavi, Jafar-Sasan

2008-09-01

The very high speech perception scores now being achieved with cochlear implants have led to demands for similar levels of achievement in music perception and perception in noisy environments. One of the crucial factors in these fields is pitch perception. The aim of the present study was to investigate the extent to which pitch perception is influenced by the intensity of the stimulus, through the use of different stimulation modes (monopolar, bipolar) and different electrodes (lateral and perimodiolar). Sixteen postlingually deafened patients with an average implant use of 3.1 years were included in this study. All patients were using a Cochlear (CI24M, CI24R, CI24RE) cochlear implant. Subjects were asked to compare the pitch of an intensity-constant reference tone with the pitch of a test tone of varying intensity. The test was repeated for apical, mediocochlear, and basal channel locations, and also for monopolar and bipolar stimulation. It was found that in monopolar stimulation 87.5% and in bipolar stimulation 85.7% of the patients perceived a clear pitch change with changing intensity of the stimulus (Spearman correlation coefficients r 0.3, respectively). A total of 73.1% of these patients perceived lower pitches with increasing intensity, 26.9% reported the opposite effect. No statistically significant difference in the intensity-pitch correlation could be found between mono- and bipolar stimulation. Neither the mean dynamic range nor the type of electrode used was found to be related to the correlation coefficient. Although the majority of today's cochlear implant recipients perform well and the intensity-pitch relation in cochlear implant recipients is still poorly understood, rising demands on speech-coding strategies may soon make a compensation of the pitch shifts desirable. Although the results of our study tend to argue against a peripheral mechanism, the exact origin of this phenomenon remains unclear.

Dynamics of fluidic devices with applications to rotor pitch links

Science.gov (United States)

Scarborough, Lloyd H., III

Coupling a Fluidic Flexible Matrix Composite (F2MC) to an air-pressurized fluid port produces a fundamentally new class of tunable vibration isolator. This fluidlastic device provides significant vibration reduction at an isolation frequency that can be tuned over a broad frequency range. The material properties and geometry of the F2MC element, as well as the port inertance, determine the isolation frequency. A unique feature of this device is that the port inertance depends on pressure so the isolation frequency can be adjusted by changing the air pressure. For constant port inertance, the isolation frequency is largely independent of the isolated mass so the device is robust to changes in load. A nonlinear model is developed to predict isolator length and port inertance. The model is linearized and the frequency response calculated. Experiments agree with theory, demonstrating a tunable isolation range from 9 Hz to 36 Hz and transmitted force reductions of up to 60 dB at the isolation frequency. Replacing rigid pitch links on rotorcraft with coupled fluidic devices has the potential to reduce the aerodynamic blade loads transmitted through the pitch links to the swashplate. Analytical models of two fluidic devices coupled with three different fluidic circuits are derived. These passive fluidlastic systems are tuned, by varying the fluid inertances and capacitances of each fluidic circuit, to reduce the transmitted pitch-link loads. The different circuit designs result in transmitted pitch link loads reduction at up to three main rotor harmonics. The simulation results show loads reduction at the targeted out-of-phase and in-phase harmonics of up to 88% and 93%, respectively. Experimental validation of two of the fluidic circuits demonstrates loads reduction of up to 89% at the out-of-phase isolation frequencies and up to 81% at the in-phase isolation frequencies. Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional

Relationship between noise, dose, and pitch in cardiac multi-detector row CT.

Science.gov (United States)

Primak, Andrew N; McCollough, Cynthia H; Bruesewitz, Michael R; Zhang, Jie; Fletcher, Joel G

2006-01-01

In spiral computed tomography (CT), dose is always inversely proportional to pitch. However, the relationship between noise and pitch (and hence noise and dose) depends on the scanner type (single vs multi-detector row) and reconstruction mode (cardiac vs noncardiac). In single detector row spiral CT, noise is independent of pitch. Conversely, in noncardiac multi-detector row CT, noise depends on pitch because the spiral interpolation algorithm makes use of redundant data from different detector rows to decrease noise for pitch values less than 1 (and increase noise for pitch values > 1). However, in cardiac spiral CT, redundant data cannot be used because such data averaging would degrade the temporal resolution. Therefore, the behavior of noise versus pitch returns to the single detector row paradigm, with noise being independent of pitch. Consequently, since faster rotation times require lower pitch values in cardiac multi-detector row CT, dose is increased without a commensurate decrease in noise. Thus, the use of faster rotation times will improve temporal resolution, not alter noise, and increase dose. For a particular application, the higher dose resulting from faster rotation speeds should be justified by the clinical benefits of the improved temporal resolution. RSNA, 2006

Lower extremity muscle activation during baseball pitching.

Science.gov (United States)

Campbell, Brian M; Stodden, David F; Nixon, Megan K

2010-04-01

The purpose of this study was to investigate muscle activation levels of select lower extremity muscles during the pitching motion. Bilateral surface electromyography data on 5 lower extremity muscles (biceps femoris, rectus femoris, gluteus maximus, vastus medialis, and gastrocnemius) were collected on 11 highly skilled baseball pitchers and compared with individual maximal voluntary isometric contraction (MVIC) data. The pitching motion was divided into 4 distinct phases: phase 1, initiation of pitching motion to maximum stride leg knee height; phase 2, maximum stride leg knee height to stride foot contact (SFC); phase 3, SFC to ball release; and phase 4, ball release to 0.5 seconds after ball release (follow-through). Results indicated that trail leg musculature elicited moderate to high activity levels during phases 2 and 3 (38-172% of MVIC). Muscle activity levels of the stride leg were moderate to high during phases 2-4 (23-170% of MVIC). These data indicate a high demand for lower extremity strength and endurance. Specifically, coaches should incorporate unilateral and bilateral lower extremity exercises for strength improvement or maintenance and to facilitate dynamic stabilization of the lower extremities during the pitching motion.

Series pid pitch controller of large wind turbines generator

Directory of Open Access Journals (Sweden)

Micić Aleksandar D.

2015-01-01

Full Text Available For this stable process with oscillatory dynamics, characterized with small damping ratio and dominant transport delay, design of the series PID pitch controller is based on the model obtained from the open-loop process step response, filtered with the second-order Butterworth filter Fbw. Performance of the series PID pitch controller, with the filter Fbw, is analyzed by simulations of the set-point and input/output disturbance responses, including simulations with a colored noise added to the control variable. Excellent performance/robustness tradeoff is obtained, compared to the recently proposed PI pitch controllers and to the modified internal model pitch controller, developed here, which has a natural mechanism to compensate effect of dominant transport delay. [Projekat Ministarstva nauke Republike Srbije, br. III 47016

Determination of pitch rotation in a spherical birefringent microparticle

Science.gov (United States)

Roy, Basudev; Ramaiya, Avin; Schäffer, Erik

2018-03-01

Rotational motion of a three dimensional spherical microscopic object can happen either in pitch, yaw or roll fashion. Among these, the yaw motion has been conventionally studied using the intensity of scattered light from birefringent microspheres through crossed polarizers. Up until now, however, there is no way to study the pitch motion in spherical microspheres. Here, we suggest a new method to study the pitch motion of birefringent microspheres under crossed polarizers by measuring the 2-fold asymmetry in the scattered signal either using video microscopy or with optical tweezers. We show a couple of simple examples of pitch rotation determination using video microscopy for a microsphere attached with a kinesin molecule while moving along a microtubule and of a particle diffusing freely in water.

Congenital amusics use a secondary pitch mechanism to identify lexical tones.

Science.gov (United States)

Bones, Oliver; Wong, Patrick C M

2017-09-01

Amusia is a pitch perception disorder associated with deficits in processing and production of both musical and lexical tones, which previous reports have suggested may be constrained to fine-grained pitch judgements. In the present study speakers of tone-languages, in which lexical tones are used to convey meaning, identified words present in chimera stimuli containing conflicting pitch-cues in the temporal fine-structure and temporal envelope, and which therefore conveyed two distinct utterances. Amusics were found to be more likely than controls to judge the word according to the envelope pitch-cues. This demonstrates that amusia is not associated with fine-grained pitch judgements alone, and is consistent with there being two distinct pitch mechanisms and with amusics having an atypical reliance on a secondary mechanism based upon envelope cues. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Absolute Pitch: Effects of Timbre on Note-Naming Ability

OpenAIRE

Vanzella, Patr?cia; Schellenberg, E. Glenn

2010-01-01

Background Absolute pitch (AP) is the ability to identify or produce isolated musical tones. It is evident primarily among individuals who started music lessons in early childhood. Because AP requires memory for specific pitches as well as learned associations with verbal labels (i.e., note names), it represents a unique opportunity to study interactions in memory between linguistic and nonlinguistic information. One untested hypothesis is that the pitch of voices may be difficult for AP poss...

Shoulder joint velocity during fastball pitching in baseball

NARCIS (Netherlands)

Gasparutto, X.; van der Graaff, E; van der Helm, F.C.T.; Veeger, H.E.J.; Colloud, F.; Domalain, M.; Monnet, T.

2015-01-01

The purpose of this study was to assess the rotation and translation velocity of the shoulder complex during fastball pitching in baseball. 8 pitchers from the Dutch AAA team performed each 3 fastball pitches. Their motion was recorded by an opto-electronic device. Kinematic computation was

Analysis of pitch system data for condition monitoring

DEFF Research Database (Denmark)

Nielsen, Jannie Sønderkær; van de Pieterman, René P.; Sørensen, John Dalsgaard

2014-01-01

with a theoretical model based on aeroelastic simulations. The blade moment is found to have only minor influence on the friction in the blade bearing. The main factors affecting the static friction are the temperature and time after the latest pitch movement. Pitch motor current and torque are proportional...

Pulping Variables, Storage Time and Pitch Deposit | Ogunwusi ...

African Journals Online (AJOL)

Pulp resin is also influenced by effective alkali concentration of the pulping medium. With increase in effective alkali concentration from 13% to 15%, pulp pitch is reduced. The interaction effect of storage and effective alkali concentration was not significant indicating that reduction in pulp pitch caused by effective alkali ...

Experimental investigation of a supercritical airfoil boundary layer in pitching motion

Energy Technology Data Exchange (ETDEWEB)

Masdari, Mehran; Tabrizian, Arshia [Faculty of New Science and Technology, University of Tehran, Tehran (Iran, Islamic Republic of); Jahanmiri, Mohsen; Gorji, Mohamamd [Dept. of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Soltani, Mohammad Reza [Dept. of Aerospace Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

2017-01-15

In this study, the boundary layer velocity profile on the upper surface of a supercritical airfoil in a forced sinusoidal pitching motion was measured and experimentally investigated. Measurements were performed using a boundary layer rake, including total pressure tubes positioned at 25 % of the chord far from the leading edge on the upper surface. For static measurements, the effects of the angle of attack between −3° and 14° and free-stream velocity between 40 m/s and 70 m/s were investigated; for dynamic measurements, the effects of oscillation amplitude variation between ±3° and ±10°, reduced frequency from 0.007 to 0.0313, and mean angle of attack between −3° and 6° were studied during one oscillation cycle. Results indicated that the boundary layer thickness decreased in upstroke motion. Increasing the oscillation frequency led to the extension of hysteresis loops. Fast Fourier transform was used on pressure signals to study the amplitude of the dominant frequency in the velocity profile. Spectral analysis showed that the dominant forced frequency of oscillation in the boundary layer and the amplitude of this frequency were varied by increasing the reduced frequency and other parameters.

The Influence of Second Harmonic Phase and Amplitude Variation in Cyclically Pitching Wings

Science.gov (United States)

Culler, Ethan; Farnsworth, John

2017-11-01

From wind tunnel testing of a cyber-physical wing model, it has been found that the pitch trajectory for stall flutter is described by an array of higher harmonic frequencies with decaying energy content. These frequencies distort the stall flutter motion from that of a pure sinusoidal oscillation in pitch and can have a significant effect on the resulting force production. In order to understand how these higher harmonic frequencies contribute to the overall pitching moment characteristics of a wing in stall flutter, a rigid finite span wing model, with aspect ratio four, was pitched in the wind tunnel. The prescribed motion of the pitch cycle was varied by changing the amplitude ratio and phase of the second harmonic of the oscillation frequency. The second harmonic represents the second highest energy mode in the pitching cycle spectra. Pitching moment and planar particle image velocimetry data was collected. From these pitching trajectories, a significant dependence of pitching moment on both the phase and amplitude of the prescribed waveforms was found. Specifically, for the same amplitude ratio, variations in the phase produced changes of approximately 30 percent in the phase averaged pitching moment.

Spectral Envelope Transformation in Singing Voice for Advanced Pitch Shifting

Directory of Open Access Journals (Sweden)

José L. Santacruz

2016-11-01

Full Text Available The aim of the present work is to perform a step towards more natural pitch shifting techniques in singing voice for its application in music production and entertainment systems. In this paper, we present an advanced method to achieve natural modifications when applying a pitch shifting process to singing voice by modifying the spectral envelope of the audio excerpt. To this end, an all-pole model has been selected to model the spectral envelope, which is estimated using a constrained non-linear optimization. The analysis of the global variations of the spectral envelope was carried out by identifying changes of the parameters of the model along with the changes of the pitch. With the obtained spectral envelope transformation functions, we applied our pitch shifting scheme to some sustained vowels in order to compare results with the same transformation made by using the Flex Pitch plugin of Logic Pro X and pitch synchronous overlap and add technique (PSOLA. This comparison has been carried out by means of both an objective and a subjective evaluation. The latter was done with a survey open to volunteers on our website.

Crackle Pitch Rises Progressively during Inspiration in Pneumonia, CHF, and IPF Patients.

Science.gov (United States)

Vyshedskiy, Andrey; Murphy, Raymond

2012-01-01

Objective. It is generally accepted that crackles are due to sudden opening of airways and that larger airways produce crackles of lower pitch than smaller airways do. As larger airways are likely to open earlier in inspiration than smaller airways and the reverse is likely to be true in expiration, we studied crackle pitch as a function of crackle timing in inspiration and expiration. Our goal was to see if the measurement of crackle pitch was consistent with this theory. Methods. Patients with a significant number of crackles were examined using a multichannel lung sound analyzer. These patients included 34 with pneumonia, 38 with heart failure, and 28 with interstitial fibrosis. Results. Crackle pitch progressively increased during inspirations in 79% of all patients. In these patients crackle pitch increased by approximately 40 Hz from the early to midinspiration and by another 40 Hz from mid to late-inspiration. In 10% of patients, crackle pitch did not change and in 11% of patients crackle pitch decreased. During expiration crackle pitch progressively decreased in 72% of patients and did not change in 28% of patients. Conclusion. In the majority of patients, we observed progressive crackle pitch increase during inspiration and decrease during expiration. Increased crackle pitch at larger lung volumes is likely a result of recruitment of smaller diameter airways. An alternate explanation is that crackle pitch may be influenced by airway tension that increases at greater lung volume. In any case improved understanding of the mechanism of production of these common lung sounds may help improve our understanding of pathophysiology of these disorders.

Effect of head pitch and roll orientations on magnetically induced vertigo.

Science.gov (United States)

Mian, Omar S; Li, Yan; Antunes, Andre; Glover, Paul M; Day, Brian L

2016-02-15

Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole-body rotation. The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals. The hypothesis predicts that the perception of whole-body rotation will depend on head orientation in the field. Results showed that the direction and magnitude of apparent whole-body rotation while stationary in a 7 T magnetic field is influenced by head orientation. The data are compatible with the Lorentz force hypothesis of magnetic vestibular stimulation and furthermore demonstrate the operation of a spatial transformation process from head-referenced vestibular signals to Earth-referenced body motion. High strength static magnetic fields are known to induce vertigo, believed to be via stimulation of the vestibular system. The leading hypothesis (Lorentz forces) predicts that the induced vertigo should depend on the orientation of the magnetic field relative to the head. In this study we examined the effect of static head pitch (-80 to +40 deg; 12 participants) and roll (-40 to +40 deg; 11 participants) on qualitative and quantitative aspects of vertigo experienced in the dark by healthy humans when exposed to the static uniform magnetic field inside a 7 T MRI scanner. Three participants were additionally examined at 180 deg pitch and roll orientations. The effect of roll orientation on horizontal and vertical nystagmus was also measured and was found to affect only the vertical component. Vertigo was most discomforting when head pitch was around 60 deg extension and was mildest when it was around 20 deg flexion. Quantitative analysis of vertigo focused on the induced perception of horizontal-plane rotation reported online with the aid of hand-held switches. Head orientation had effects on both the magnitude and the direction of this perceived rotation. The data suggest

Rapid area change in pitch-up manoeuvres of small perching birds.

Science.gov (United States)

Polet, D T; Rival, D E

2015-10-26

Rapid pitch-up has been highlighted as a mechanism to generate large lift and drag during landing manoeuvres. However, pitching rates had not been measured previously in perching birds, and so the direct applicability of computations and experiments to observed behaviour was not known. We measure pitch rates in a small, wild bird (the black-capped chickadee; Poecile atricapillus), and show that these rates are within the parameter range used in experiments. Pitching rates were characterized by the shape change number, a metric comparing the rate of frontal area increase to acceleration. Black-capped chickadees increase the shape change number during perching in direct proportion to their total kinetic and potential energy at the start of the manoeuvre. The linear relationship between dissipated energy and shape change number is in accordance with a simple analytical model developed for two-dimensional pitching and decelerating airfoils. Black-capped chickadees use a wing pitch-up manoeuvre during perching to dissipate energy quickly while maintaining lift and drag through rapid area change. It is suggested that similar pitch-and-decelerate manoeuvres could be used to aid in the controlled, precise landings of small manoeuvrable air vehicles.

Auditory working memory predicts individual differences in absolute pitch learning.

Science.gov (United States)

Van Hedger, Stephen C; Heald, Shannon L M; Koch, Rachelle; Nusbaum, Howard C

2015-07-01

Absolute pitch (AP) is typically defined as the ability to label an isolated tone as a musical note in the absence of a reference tone. At first glance the acquisition of AP note categories seems like a perceptual learning task, since individuals must assign a category label to a stimulus based on a single perceptual dimension (pitch) while ignoring other perceptual dimensions (e.g., loudness, octave, instrument). AP, however, is rarely discussed in terms of domain-general perceptual learning mechanisms. This is because AP is typically assumed to depend on a critical period of development, in which early exposure to pitches and musical labels is thought to be necessary for the development of AP precluding the possibility of adult acquisition of AP. Despite this view of AP, several previous studies have found evidence that absolute pitch category learning is, to an extent, trainable in a post-critical period adult population, even if the performance typically achieved by this population is below the performance of a "true" AP possessor. The current studies attempt to understand the individual differences in learning to categorize notes using absolute pitch cues by testing a specific prediction regarding cognitive capacity related to categorization - to what extent does an individual's general auditory working memory capacity (WMC) predict the success of absolute pitch category acquisition. Since WMC has been shown to predict performance on a wide variety of other perceptual and category learning tasks, we predict that individuals with higher WMC should be better at learning absolute pitch note categories than individuals with lower WMC. Across two studies, we demonstrate that auditory WMC predicts the efficacy of learning absolute pitch note categories. These results suggest that a higher general auditory WMC might underlie the formation of absolute pitch categories for post-critical period adults. Implications for understanding the mechanisms that underlie the

A comparative Tg-Ms study of the carbonization behaviour of different pitches

Energy Technology Data Exchange (ETDEWEB)

Garcia, R.; Arenillas, A.; Crespo, J.L.; Pis, J.J.; Moinelo, S.R. [CSIC, Oviedo (Spain). Inst. Nacional del Carbon

2002-08-01

The purpose of this work was to study the formation of mesophase spherules from a low-temperature coal tar pitch under carbonization conditions. For comparison, the carbonization of a high-temperature coal tar pitch and a petroleum pitch were also considered. Different degrees of mesophase formation and development for each pitch. The results from Fourier transform infrared spectroscopy (FT-IR), elemental analysis, and the thermogravimetric analyzer mass spectrometer (TG-MS) tests were compared with the different extents of mesophase formation, checked by optical microscopy. According to the results, several stages can be distinguished as temperature increases in the carbonization process of the pitches. In the low-temperature coal tar pitch, the devolatilization of light components, especially phenols, accounts for the most significant weight loss. Moreover, cross-linking contributes greatly to the formation and development of mesophase, resulting in the predominance of bulk mesophase in a relatively short time in the case of the low-temperature coal tar pitch. 19 refs., 10 figs., 2 tabs.

Prediction of HS Soderberg plant PAH emissions from a laboratory evaluation of a pitch

Energy Technology Data Exchange (ETDEWEB)

Castonguay, L.; Mirtchi, A. A.; Proulx, A. L.; Savard, G.; Simard, E.; Steward, N.; Tremblay, C. [Alcan International Ltd., Arvida Research and Development Centre, Jonquiere, PQ (Canada)

1998-12-31

The presence of certain polycyclic aromatic hydrocarbons (PAHs) in coal tar pitch has been identified as a possible limit to the long-term viability of horizontal stud (HS) Soderberg technology, a technology of importance in the aluminum industry. This paper presents the results of a comparative study of pitch PAH content and HS Soderberg cell emissions. Laboratory results are compared with plant emissions for two regular and low PAH pitches with the same softening points. The results indicate the existence of a correlation between pitch PAH content and cell emission, which is valid for regular tar pitches, low tar pitches, as well as for hybrid pitches. These findings make it possible to predict the quantity and distribution of HS Soderberg cell PAH emissions from the analysis of PAHs in the pitch. The results also justify the conclusion that the emission of genotoxic compounds from pitch in the HS Soderberg technology can be decreased by using a pitch with low PAH content. 4 refs., 5 tabs., 5 figs.

Crackle Pitch Rises Progressively during Inspiration in Pneumonia, CHF, and IPF Patients

Directory of Open Access Journals (Sweden)

Andrey Vyshedskiy

2012-01-01

Methods. Patients with a significant number of crackles were examined using a multichannel lung sound analyzer. These patients included 34 with pneumonia, 38 with heart failure, and 28 with interstitial fibrosis. Results. Crackle pitch progressively increased during inspirations in 79% of all patients. In these patients crackle pitch increased by approximately 40 Hz from the early to midinspiration and by another 40 Hz from mid to late-inspiration. In 10% of patients, crackle pitch did not change and in 11% of patients crackle pitch decreased. During expiration crackle pitch progressively decreased in 72% of patients and did not change in 28% of patients. Conclusion. In the majority of patients, we observed progressive crackle pitch increase during inspiration and decrease during expiration. Increased crackle pitch at larger lung volumes is likely a result of recruitment of smaller diameter airways. An alternate explanation is that crackle pitch may be influenced by airway tension that increases at greater lung volume. In any case improved understanding of the mechanism of production of these common lung sounds may help improve our understanding of pathophysiology of these disorders.

arXiv Signal coupling to embedded pitch adapters in silicon sensors

CERN Document Server

Artuso, M.; Bezshyiko, I.; Blusk, S.; Bruendler, R.; Bugiel, S.; Dasgupta, R.; Dendek, A.; Dey, B.; Ely, S.; Lionetto, F.; Petruzzo, M.; Polyakov, I.; Rudolph, M.; Schindler, H.; Steinkamp, O.; Stone, S.

2018-01-01

We have examined the effects of embedded pitch adapters on signal formation in n-substrate silicon microstrip sensors with data from beam tests and simulation. According to simulation, the presence of the pitch adapter metal layer changes the electric field inside the sensor, resulting in slowed signal formation on the nearby strips and a pick-up effect on the pitch adapter. This can result in an inefficiency to detect particles passing through the pitch adapter region. All these effects have been observed in the beam test data.

Variability of a "force signature" during windmill softball pitching and relationship between discrete force variables and pitch velocity.

Science.gov (United States)

Nimphius, Sophia; McGuigan, Michael R; Suchomel, Timothy J; Newton, Robert U

2016-06-01

This study assessed reliability of discrete ground reaction force (GRF) variables over multiple pitching trials, investigated the relationships between discrete GRF variables and pitch velocity (PV) and assessed the variability of the "force signature" or continuous force-time curve during the pitching motion of windmill softball pitchers. Intraclass correlation coefficient (ICC) for all discrete variables was high (0.86-0.99) while the coefficient of variance (CV) was low (1.4-5.2%). Two discrete variables were significantly correlated to PV; second vertical peak force (r(5)=0.81, p=0.03) and time between peak forces (r(5)=-0.79; p=0.03). High ICCs and low CVs support the reliability of discrete GRF and PV variables over multiple trials and significant correlations indicate there is a relationship between the ability to produce force and the timing of this force production with PV. The mean of all pitchers' curve-average standard deviation of their continuous force-time curves demonstrated low variability (CV=4.4%) indicating a repeatable and identifiable "force signature" pattern during this motion. As such, the continuous force-time curve in addition to discrete GRF variables should be examined in future research as a potential method to monitor or explain changes in pitching performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface Electromyography of the Forearm Musculature During the Windmill Softball Pitch

Science.gov (United States)

Remaley, D. Trey; Fincham, Bryce; McCullough, Bryan; Davis, Kirk; Nofsinger, Charles; Armstrong, Charles; Stausmire, Julie M.

2015-01-01

Background: Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published. Purpose: Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined. Study Design: Descriptive laboratory study. Methods: Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball. Results: During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o’clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball. Conclusion: During the 6

Surface Electromyography of the Forearm Musculature During the Windmill Softball Pitch.

Science.gov (United States)

Remaley, D Trey; Fincham, Bryce; McCullough, Bryan; Davis, Kirk; Nofsinger, Charles; Armstrong, Charles; Stausmire, Julie M

2015-01-01

Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published. Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined. Descriptive laboratory study. Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball. During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o'clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball. During the 6 pitches, the greatest muscular activity was in phases 5 and 6

Joint Pitch and DOA Estimation Using the ESPRIT method

DEFF Research Database (Denmark)

Wu, Yuntao; Amir, Leshem; Jensen, Jesper Rindom

2015-01-01

In this paper, the problem of joint multi-pitch and direction-of-arrival (DOA) estimation for multi-channel harmonic sinusoidal signals is considered. A spatio-temporal matrix signal model for a uniform linear array is defined, and then the ESPRIT method based on subspace techniques that exploits...... the invariance property in the time domain is first used to estimate the multi pitch frequencies of multiple harmonic signals. Followed by the estimated pitch frequencies, the DOA estimations based on the ESPRIT method are also presented by using the shift invariance structure in the spatial domain. Compared...... to the existing stateof-the-art algorithms, the proposed method based on ESPRIT without 2-D searching is computationally more efficient but performs similarly. An asymptotic performance analysis of the DOA and pitch estimation of the proposed method are also presented. Finally, the effectiveness of the proposed...

Risk-based Comparative Study of Fluid Power Pitch Concepts

DEFF Research Database (Denmark)

Liniger, Jesper; Pedersen, Henrik Clemmensen; N. Soltani, Mohsen

2017-01-01

Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk....... Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where...

The musical environment and auditory plasticity: Hearing the pitch of percussion

Directory of Open Access Journals (Sweden)

Neil M Mclachlan

2013-10-01

Full Text Available Although musical skills clearly improve with training, pitch processing has generally been believed to be biologically determined by the behavior of brain stem neural mechanisms. Two main classes of pitch models have emerged over the last 50 years. Harmonic template models have been used to explain cross-channel integration of frequency information, and waveform periodicity models have been used to explain pitch discrimination that is much finer than the resolution of the auditory nerve. It has been proposed that harmonic templates are learnt from repeated exposure to voice, and so it may also be possible to learn inharmonic templates from repeated exposure to inharmonic music instruments. This study investigated whether pitch-matching accuracy for inharmonic percussion instruments was better in people who have trained on these instruments and could reliably recognize their timbre. We found that adults who had trained with Indonesian gamelan instruments were better at recognizing and pitch-matching gamelan instruments than people with similar levels of music training, but no prior exposure to these instruments. These findings suggest that gamelan musicians were able to use inharmonic templates to support accurate pitch processing for these instruments. We suggest that recognition mechanisms based on spectrotemporal patterns of afferent auditory excitation in the early stages of pitch processing allow rapid priming of the lowest frequency partial of inharmonic timbres, explaining how music training can adapt pitch processing to different musical genres and instruments.

Half pitch lower sound perception caused by carbamazepine.

Science.gov (United States)

Konno, Shyu; Yamazaki, Etsuko; Kudoh, Masako; Abe, Takashi; Tohgi, Hideo

2003-09-01

We report a 16-year-old woman with secondary generalization of partial seizure, who complained of an auditory disturbance after carbamazepine (CBZ) administration. She had been taking sodium valproate (VPA) from the age of 15. However, her seizures remained poorly controlled. We changed her antiepileptic drug from VPA to CBZ. At 1 week after CBZ administration, she noticed that electone musical performances were heard as a semitone lower. When oral administration of CBZ was stopped, her pitch perception returned to normal. If she had not been able to discern absolute pitch, she might have been unable to recognize her lowered pitch perception. Auditory disturbance caused by CBZ is reversible and very rare.

Contact angle hysteresis on superhydrophobic stripes.

Science.gov (United States)

Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

2014-08-21

We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

"Turn Up the Taste": Assessing the Role of Taste Intensity and Emotion in Mediating Crossmodal Correspondences between Basic Tastes and Pitch.

Science.gov (United States)

Wang, Qian Janice; Wang, Sheila; Spence, Charles

2016-05-01

People intuitively match basic tastes to sounds of different pitches, and the matches that they make tend to be consistent across individuals. It is, though, not altogether clear what governs such crossmodal mappings between taste and auditory pitch. Here, we assess whether variations in taste intensity influence the matching of taste to pitch as well as the role of emotion in mediating such crossmodal correspondences. Participants were presented with 5 basic tastants at 3 concentrations. In Experiment 1, the participants rated the tastants in terms of their emotional arousal and valence/pleasantness, and selected a musical note (from 19 possible pitches ranging from C2 to C8) and loudness that best matched each tastant. In Experiment 2, the participants made emotion ratings and note matches in separate blocks of trials, then made emotion ratings for all 19 notes. Overall, the results of the 2 experiments revealed that both taste quality and concentration exerted a significant effect on participants' loudness selection, taste intensity rating, and valence and arousal ratings. Taste quality, not concentration levels, had a significant effect on participants' choice of pitch, but a significant positive correlation was observed between individual perceived taste intensity and pitch choice. A significant and strong correlation was also demonstrated between participants' valence assessments of tastants and their valence assessments of the best-matching musical notes. These results therefore provide evidence that: 1) pitch-taste correspondences are primarily influenced by taste quality, and to a lesser extent, by perceived intensity; and 2) such correspondences may be mediated by valence/pleasantness. © The Author 2016. Published by Oxford University Press.

Importance of helical pitch parameter in LHD-type heliotron reactor designs

International Nuclear Information System (INIS)

Goto, T.; Suzuki, Y.; Yanagi, N.; Watanabe, K.Y.; Imagawa, S.; Sagara, A.

2010-11-01

In the design studies of the LHD-type heliotron reactors, one of the key issues is to secure sufficient blanket spaces. In this respect, helical pitch parameter γ is quite important because it significantly affects both the coil and plasma shapes. In order to understand the effect of helical pitch parameter on the design window quantitatively, a system design code for the LHD-type heliotron reactors has been developed and parametric scans were carried out with 3 cases of γ=1.15, 1.20 and 1.25. It becomes clear that the possible design window of heliotron reactors strongly depends on the engineering constraints: stored magnetic energy of coil system, blanket space, and neutron wall load. γ=1.20 is optimum from the viewpoint of moderating the physics requirements, but γ=1.15 has a robustness to the change in the physics and engineering conditions. Since the design windows are quite sensitive to the engineering constraints and physics conditions, the further detailed study on design feasibility of advanced engineering components and the effect of γ on the physics conditions is expected to optimize the value of γ. (author)

Pitch and Time, Tonality and Meter: How Do Musical Dimensions Combine?

Science.gov (United States)

Prince, Jon B.; Thompson, William F.; Schmuckler, Mark A.

2009-01-01

The authors examined how the structural attributes of tonality and meter influence musical pitch-time relations. Listeners heard a musical context followed by probe events that varied in pitch class and temporal position. Tonal and metric hierarchies contributed additively to the goodness-of-fit of probes, with pitch class exerting a stronger…

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Science.gov (United States)

2010-07-01

... 29 Labor 6 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

Petrographic characterization of the solid products of coal- pitch coprocessing

Energy Technology Data Exchange (ETDEWEB)

Potter, J.; Kybett, B.D.; McDougall, W.J.; Nambudiri, E.M.V.; Rahimi, P.; Price, J.T.

1986-06-01

Petrographic studies were conducted on four solid residues resulting from the hydrogenation process of 1) Forestburg sub- bituminous coal alone, 2) the coal with a non-coking solvent (anthracene oil), 3) pitch (Cold Lake vacuum-bottom deposits), and 4) a mixture of coal and pitch. The purpose was to determine the amounts of coal and pitch-derived solids in the residues. All the residues were produced under identical severe conditions of liquefaction to promote the formation of solids. The coal processed with anthracene oil gives a residue consisting mainly of isotropic huminitic solids. If the coal is hydrogenated under similar conditions but without a solvent, the predominant residual solids are anisotropic semicokes displaying coarse mosaic textures, which form from vitroplast. The residual products from the hydrogenated Cold Lake vacuum- bottom deposits are also dominantly anisotropic semicokes; these display coarse mosaics and flow textures, and form by the growth and coalescence of mesophase spherules. Both coal- and pitch-derived solids are identified in a residue produced by coprocessing the Forestburg coal with the pitch from the Cold Lake vacuum-bottom deposits. It is concluded that the huminite macerals in the coal generate the fine-grained, mosaic-textured semicokes, whereas the pitch produces the coarse mosaics and flow-textured semicokes.

Permanent magnet assembly producing a strong tilted homogeneous magnetic field: towards magic angle field spinning NMR and MRI.

Science.gov (United States)

Sakellariou, Dimitris; Hugon, Cédric; Guiga, Angelo; Aubert, Guy; Cazaux, Sandrine; Hardy, Philippe

2010-12-01

We introduce a cylindrical permanent magnet design that generates a homogeneous and strong magnetic field having an arbitrary inclination with respect to the axis of the cylinder. The analytical theory of 3 D magnetostatics has been applied to this problem, and a hybrid magnet structure has been designed. This structure contains two magnets producing a longitudinal and transverse component for the magnetic field, whose amplitudes and homogeneities can be fully controlled by design. A simple prototype has been constructed using inexpensive small cube magnets, and its magnetic field has been mapped using Hall and NMR probe sensors. This magnet can, in principle, be used for magic angle field spinning NMR and MRI experiments allowing for metabolic chemical shift profiling in small living animals. Copyright © 2010 John Wiley & Sons, Ltd.

Long-term pitch memory for music recordings is related to auditory working memory precision.

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Van Hedger, Stephen C; Heald, Shannon Lm; Nusbaum, Howard C

2018-04-01

Most individuals have reliable long-term memories for the pitch of familiar music recordings. This pitch memory (1) appears to be normally distributed in the population, (2) does not depend on explicit musical training and (3) only seems to be weakly related to differences in listening frequency estimates. The present experiment was designed to assess whether individual differences in auditory working memory could explain variance in long-term pitch memory for music recordings. In Experiment 1, participants first completed a musical note adjustment task that has been previously used to assess working memory of musical pitch. Afterward, participants were asked to judge the pitch of well-known music recordings, which either had or had not been shifted in pitch. We found that performance on the pitch working memory task was significantly related to performance in the pitch memory task using well-known recordings, even when controlling for overall musical experience and familiarity with each recording. In Experiment 2, we replicated these findings in a separate group of participants while additionally controlling for fluid intelligence and non-pitch-based components of auditory working memory. In Experiment 3, we demonstrated that participants could not accurately judge the pitch of unfamiliar recordings, suggesting that our method of pitch shifting did not result in unwanted acoustic cues that could have aided participants in Experiments 1 and 2. These results, taken together, suggest that the ability to maintain pitch information in working memory might lead to more accurate long-term pitch memory.

Performance Demands in Softball Pitching: A Comprehensive Muscle Fatigue Study.

Science.gov (United States)

Corben, Jeffrey S; Cerrone, Sara A; Soviero, Julie E; Kwiecien, Susan Y; Nicholas, Stephen J; McHugh, Malachy P

2015-08-01

Monitoring pitch count is standard practice in minor league baseball but not in softball because of the perception that fast-pitch softball pitching is a less stressful motion. To examine muscle fatigue after fast-pitch softball performances to provide an assessment of performance demand. Descriptive laboratory study. Bilateral strength measurements (handheld dynamometer) were made on 19 female softball pitchers (mean age [±SD], 15.2 ± 1.2 years) before and after pitching a game (mean number of pitches, 99 ± 21; mean innings pitched, 5 ± 1). A total of 20 tests were performed on the dominant and nondominant sides: forearm (grip, wrist flexion/extension, pronation/supination, elbow flexion/extension), shoulder (flexion, abduction/adduction, external/internal rotation, empty can test), scapula (middle/lower trapezius, rhomboid), and hip (hip flexion/extension, abduction/adduction). Fatigue (percentage strength loss) was categorized based on bilateral versus unilateral presentation using paired t tests: bilateral symmetric (significant on dominant and nondominant and not different between sides), bilateral asymmetric (significant on dominant and nondominant but significantly greater on dominant), unilateral asymmetric (significant on dominant only and significantly greater than nondominant), or unilateral equivocal (significant on dominant only but not different from nondominant). Bilateral symmetric fatigue was evident for all hip (dominant, 19.3%; nondominant, 15.2%) and scapular tests (dominant, 19.2%; nondominant, 19.3%). In general, shoulder tests exhibited bilateral asymmetric fatigue (dominant, 16.9%; nondominant, 11.6%). Forearm tests were more variable, with bilateral symmetric fatigue in the elbow flexors (dominant, 22.5%; nondominant, 19.2%), and wrist flexors (dominant, 21.6%; nondominant, 19.0%), bilateral asymmetric fatigue in the supinators (dominant, 21.8%; nondominant, 15.5%), unilateral asymmetric fatigue in the elbow extensors (dominant, 22

Unaccounted Workload Factor: Game-Day Pitch Counts in High School Baseball Pitchers—An Observational Study

Science.gov (United States)

Zaremski, Jason L.; Zeppieri, Giorgio; Jones, Deborah L.; Tripp, Brady L.; Bruner, Michelle; Vincent, Heather K.; Horodyski, MaryBeth

2018-01-01

Background: Throwing injuries are common in high school baseball. Known risk factors include excessive pitch counts, year-round pitching, and pitching with arm pain and fatigue. Despite the evidence, the prevalence of pitching injuries among high school players has not decreased. One possibility to explain this pattern is that players accumulate unaccounted pitch volume during warm-up and bullpen activity, but this has not yet been examined. Hypotheses: Our primary hypothesis was that approximately 30% to 40% of pitches thrown off a mound by high school pitchers during a game-day outing are unaccounted for in current data but will be revealed when bullpen sessions and warm-up pitches are included. Our secondary hypothesis was that there is wide variability among players in the number of bullpen pitches thrown per outing. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Researchers counted all pitches thrown off a mound during varsity high school baseball games played by 34 high schools in North Central Florida during the 2017 season. Results: We recorded 13,769 total pitches during 115 varsity high school baseball starting pitcher outings. The mean ± SD pitch numbers per game were calculated for bullpen activity (27.2 ± 9.4), warm-up (23.6 ±8.0), live games (68.9 ±19.7), and total pitches per game (119.7 ± 27.8). Thus, 42.4% of the pitches performed were not accounted for in the pitch count monitoring of these players. The number of bullpen pitches thrown varied widely among players, with 25% of participants in our data set throwing fewer than 22 pitches and 25% throwing more than 33 pitches per outing. Conclusion: In high school baseball players, pitch count monitoring does not account for the substantial volume of pitching that occurs during warm-up and bullpen activity during the playing season. These extra pitches should be closely monitored to help mitigate the risk of overuse injury. PMID:29662911

Unaccounted Workload Factor: Game-Day Pitch Counts in High School Baseball Pitchers-An Observational Study.

Science.gov (United States)

Zaremski, Jason L; Zeppieri, Giorgio; Jones, Deborah L; Tripp, Brady L; Bruner, Michelle; Vincent, Heather K; Horodyski, MaryBeth

2018-04-01

Throwing injuries are common in high school baseball. Known risk factors include excessive pitch counts, year-round pitching, and pitching with arm pain and fatigue. Despite the evidence, the prevalence of pitching injuries among high school players has not decreased. One possibility to explain this pattern is that players accumulate unaccounted pitch volume during warm-up and bullpen activity, but this has not yet been examined. Our primary hypothesis was that approximately 30% to 40% of pitches thrown off a mound by high school pitchers during a game-day outing are unaccounted for in current data but will be revealed when bullpen sessions and warm-up pitches are included. Our secondary hypothesis was that there is wide variability among players in the number of bullpen pitches thrown per outing. Cross-sectional study; Level of evidence, 3. Researchers counted all pitches thrown off a mound during varsity high school baseball games played by 34 high schools in North Central Florida during the 2017 season. We recorded 13,769 total pitches during 115 varsity high school baseball starting pitcher outings. The mean ± SD pitch numbers per game were calculated for bullpen activity (27.2 ± 9.4), warm-up (23.6 ±8.0), live games (68.9 ±19.7), and total pitches per game (119.7 ± 27.8). Thus, 42.4% of the pitches performed were not accounted for in the pitch count monitoring of these players. The number of bullpen pitches thrown varied widely among players, with 25% of participants in our data set throwing fewer than 22 pitches and 25% throwing more than 33 pitches per outing. In high school baseball players, pitch count monitoring does not account for the substantial volume of pitching that occurs during warm-up and bullpen activity during the playing season. These extra pitches should be closely monitored to help mitigate the risk of overuse injury.

The qualitative criterion of transient angle stability

DEFF Research Database (Denmark)

Lyu, R.; Xue, Y.; Xue, F.

2015-01-01

In almost all the literatures, the qualitative assessment of transient angle stability extracts the angle information of generators based on the swing curve. As the angle (or angle difference) of concern and the threshold value rely strongly on the engineering experience, the validity and robust...... of these criterions are weak. Based on the stability mechanism from the extended equal area criterion (EEAC) theory and combining with abundant simulations of real system, this paper analyzes the criterions in most literatures and finds that the results could be too conservative or too optimistic. It is concluded...

Absence of modulatory action on haptic height perception with musical pitch

Directory of Open Access Journals (Sweden)

Michele eGeronazzo

2015-09-01

Full Text Available Although acoustic frequency is not a spatial property of physical objects, in common language, pitch, i.e., the psychological correlated of frequency, is often labeled spatially (i.e., high in pitch or low in pitch. Pitch-height is known to modulate (and interact with the response of participants when they are asked to judge spatial properties of non-auditory stimuli (e.g., visual in a variety of behavioral tasks. In the current study we investigated whether the modulatory action of pitch-height extended to the haptic estimation of height of a virtual step.We implemented a HW/SW setup which is able to render virtual 3D objects (stair-steps haptically through a PHANTOM device, and to provide real-time continuous auditory feedback depending on the user interaction with the object. The haptic exploration was associated with a sinusoidal tone whose pitch varied as a function of the interaction point’s height within (i a narrower and (ii a wider pitch range, or (iii a random pitch variation acting as a control audio condition. Explorations were also performed with no sound (haptic only. Participants were instructed to explore the virtual step freely, and to communicate height estimation by opening their thumb and index finger to mimic the step riser height, or verbally by reporting the height in centimeters of the step riser. We analyzed the role of musical expertise by dividing participants into non musicians and musicians. Results showed no effects of musical pitch on high-realistic haptic feedback. Overall there is no difference between the two groups in the proposed multimodal conditions. Additionally, we observed a different haptic response distribution between musicians and non musicians when estimations of the auditory conditions are matched with estimations in the no sound condition.

Pitch Discrimination and Melodic Memory in Children with Autism Spectrum Disorders

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Stanutz, Sandy; Wapnick, Joel; Burack, Jacob A.

2014-01-01

Background: Pitch perception is enhanced among persons with autism. We extended this finding to memory for pitch and melody among school-aged children. Objective: The purpose of this study was to investigate pitch memory in musically untrained children with autism spectrum disorders, aged 7-13 years, and to compare it to that of age- and…

Human vertical eye movement responses to earth horizontal pitch

Science.gov (United States)

Wall, C. 3rd; Petropoulos, A. E.

1993-01-01

The vertical eye movements in humans produced in response to head-over-heels constant velocity pitch rotation about a horizontal axis resemble those from other species. At 60 degrees/s these are persistent and tend to have non-reversing slow components that are compensatory to the direction of rotation. In most, but not all subjects, the slow component velocity was well characterized by a rapid build-up followed by an exponential decay to a non-zero baseline. Super-imposed was a cyclic or modulation component whose frequency corresponded to the time for one revolution and whose maximum amplitude occurred during a specific head orientation. All response components (exponential decay, baseline and modulation) were larger during pitch backward compared to pitch forward runs. Decay time constants were shorter during the backward runs, thus, unlike left to right yaw axis rotation, pitch responses display significant asymmetries between paired forward and backward runs.

Development in children's interpretation of pitch cues to emotions.

Science.gov (United States)

Quam, Carolyn; Swingley, Daniel

2012-01-01

Young infants respond to positive and negative speech prosody (A. Fernald, 1993), yet 4-year-olds rely on lexical information when it conflicts with paralinguistic cues to approval or disapproval (M. Friend, 2003). This article explores this surprising phenomenon, testing one hundred eighteen 2- to 5-year-olds' use of isolated pitch cues to emotions in interactive tasks. Only 4- to 5-year-olds consistently interpreted exaggerated, stereotypically happy or sad pitch contours as evidence that a puppet had succeeded or failed to find his toy (Experiment 1) or was happy or sad (Experiments 2, 3). Two- and 3-year-olds exploited facial and body-language cues in the same task. The authors discuss the implications of this late-developing use of pitch cues to emotions, relating them to other functions of pitch. © 2011 The Authors. Child Development © 2011 Society for Research in Child Development, Inc.

Faster decline of pitch memory over time in congenital amusia.

Science.gov (United States)

Williamson, Victoria J; McDonald, Claire; Deutsch, Diana; Griffiths, Timothy D; Stewart, Lauren

2010-04-26

Congenital amusia (amusia, hereafter) is a developmental disorder that impacts negatively on the perception of music. Psychophysical testing suggests that individuals with amusia have above average thresholds for detection of pitch change and pitch direction discrimination; however, a low-level auditory perceptual problem cannot completely explain the disorder, since discrimination of melodies is also impaired when the constituent intervals are suprathreshold for perception. The aim of the present study was to test pitch memory as a function of (a) time and (b) tonal interference, in order to determine whether pitch traces are inherently weaker in amusic individuals. Memory for the pitch of single tones was compared using two versions of a paradigm developed by Deutsch (1970a). In both tasks, participants compared the pitch of a standard (S) versus a comparison (C) tone. In the time task, the S and C tones were presented, separated in time by 0, 1, 5, 10, and 15 s (blocked presentation). In the interference task, the S and C tones were presented with a fixed time interval (5 s) but with a variable number of irrelevant tones in between 0, 2, 4, 6, and 8 tones (blocked presentation). In the time task, control performance remained high for all time intervals, but amusics showed a performance decrement over time. In the interference task, controls and amusics showed a similar performance decrement with increasing number of irrelevant tones. Overall, the results suggest that the pitch representations of amusic individuals are less stable and more prone to decay than those of matched non-amusic individuals.

Analysis of Pitch Gear Deterioration using Indicators

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2011-01-01

This work concerns a case study in the context of risk-based operation and maintenance of offshore wind turbines. For wind turbines with electrical pitch systems, deterioration can generally be observed at the pitch gear teeth; especially at the point where the blades are located during normal...... of the damage, and can be used for Bayesian updating of a damage model used for risk-based decision making. For this decision problem, the risk of failure should be compared to the cost of preventive maintenance. The hypothesis that the maximum pitch motor torque is an indicator of the damage size is supported...... changes in the temperature are the primary cause of the decrease. A model is established to remove the effect of the explained variation, and it is investigated if deterioration can be detected as changes in the peak torque. A small increase could be detected after the maintenance, but before...

Comparison of individual pitch and smart rotor control strategies for load reduction

International Nuclear Information System (INIS)

Plumley, C; Leithead, W; Jamieson, P; Bossanyi, E; Graham, M

2014-01-01

Load reduction is increasingly seen as an essential part of controller and wind turbine design. On large multi-MW wind turbines that experience high levels of wind shear and turbulence across the rotor, individual pitch control and smart rotor control are being considered. While individual pitch control involves adjusting the pitch of each blade individually to reduce the cyclic loadings on the rotor, smart rotor control involves activating control devices distributed along the blades to alter the local aerodynamics of the blades. Here we investigate the effectiveness of using a DQ-axis control and a distributed (independent) control for both individual pitch and trailing edge flap smart rotor control. While load reductions are similar amongst the four strategies across a wide range of variables, including blade root bending moments, yaw bearing and shaft, the pitch actuator requirements vary. The smart rotor pitch actuator has reduced travel, rates, accelerations and power requirements than that of the individual pitch controlled wind turbines. This benefit alone however would be hard to justify the added design complexities of using a smart rotor, which can be seen as an alternative to upgrading the pitch actuator and bearing. In addition, it is found that the independent control strategy is apt at roles that the collective pitch usually targets, such as tower motion and speed control, and it is perhaps here, in supplementing other systems, that the future of the smart rotor lies

Comparison of individual pitch and smart rotor control strategies for load reduction

Science.gov (United States)

Plumley, C.; Leithead, W.; Jamieson, P.; Bossanyi, E.; Graham, M.

2014-06-01

Load reduction is increasingly seen as an essential part of controller and wind turbine design. On large multi-MW wind turbines that experience high levels of wind shear and turbulence across the rotor, individual pitch control and smart rotor control are being considered. While individual pitch control involves adjusting the pitch of each blade individually to reduce the cyclic loadings on the rotor, smart rotor control involves activating control devices distributed along the blades to alter the local aerodynamics of the blades. Here we investigate the effectiveness of using a DQ-axis control and a distributed (independent) control for both individual pitch and trailing edge flap smart rotor control. While load reductions are similar amongst the four strategies across a wide range of variables, including blade root bending moments, yaw bearing and shaft, the pitch actuator requirements vary. The smart rotor pitch actuator has reduced travel, rates, accelerations and power requirements than that of the individual pitch controlled wind turbines. This benefit alone however would be hard to justify the added design complexities of using a smart rotor, which can be seen as an alternative to upgrading the pitch actuator and bearing. In addition, it is found that the independent control strategy is apt at roles that the collective pitch usually targets, such as tower motion and speed control, and it is perhaps here, in supplementing other systems, that the future of the smart rotor lies.

Research note: exceptional absolute pitch perception for spoken words in an able adult with autism.

Science.gov (United States)

Heaton, Pamela; Davis, Robert E; Happé, Francesca G E

2008-01-01

Autism is a neurodevelopmental disorder, characterised by deficits in socialisation and communication, with repetitive and stereotyped behaviours [American Psychiatric Association (1994). Diagnostic and statistical manual for mental disorders (4th ed.). Washington, DC: APA]. Whilst intellectual and language impairment is observed in a significant proportion of diagnosed individuals [Gillberg, C., & Coleman, M. (2000). The biology of the autistic syndromes (3rd ed.). London: Mac Keith Press; Klinger, L., Dawson, G., & Renner, P. (2002). Autistic disorder. In E. Masn, & R. Barkley (Eds.), Child pyschopathology (2nd ed., pp. 409-454). New York: Guildford Press], the disorder is also strongly associated with the presence of highly developed, idiosyncratic, or savant skills [Heaton, P., & Wallace, G. (2004) Annotation: The savant syndrome. Journal of Child Psychology and Psychiatry, 45 (5), 899-911]. We tested identification of fundamental pitch frequencies in complex tones, sine tones and words in AC, an intellectually able man with autism and absolute pitch (AP) and a group of healthy controls with self-reported AP. The analysis showed that AC's naming of speech pitch was highly superior in comparison to controls. The results suggest that explicit access to perceptual information in speech is retained to a significantly higher degree in autism.

High angle-of-attack aerodynamics of a strake-canard-wing V/STOL fighter configuration

Science.gov (United States)

Durston, D. A.; Schreiner, J. A.

1983-01-01

High angle-of-attack aerodynamic data are analyzed for a strake-canard-wing V/STOL fighter configuration. The configuration represents a twin-engine supersonic V/STOL fighter aircraft which uses four longitudinal thrust-augmenting ejectors to provide vertical lift. The data were obtained in tests of a 9.39 percent scale model of the configuration in the NASA Ames 12-Foot Pressure Wind Tunnel, at a Mach number of 0.2. Trimmed aerodynamic characteristics, longitudinal control power, longitudinal and lateral/directional stability, and effects of alternate strake and canard configurations are analyzed. The configuration could not be trimmed (power-off) above 12 deg angle of attack because of the limited pitch control power and the high degree of longitudinal instability (28 percent) at this Mach number. Aerodynamic center location was found to be controllable by varying strake size and canard location without significantly affecting lift and drag. These configuration variations had relatively little effect on the lateral/directional stability up to 10 deg angle of attack.

Uncovering phenotypes of poor-pitch singing: the Sung Performance Battery (SPB)

Science.gov (United States)

Berkowska, Magdalena; Dalla Bella, Simone

2013-01-01

Singing is as natural as speaking for humans. Increasing evidence shows that the layman can carry a tune (e.g., when asked to sing a well-known song or to imitate single pitches, intervals and short melodies). Yet, important individual differences exist in the general population with regard to singing proficiency. Some individuals are particularly inaccurate or imprecise in producing or imitating pitch information (poor-pitch singers), thus showing a variety of singing phenotypes. Unfortunately, so far there is not a standard set of tasks for assessing singing proficiency in the general population, allowing to uncover and characterize individual profiles of poor-pitch singing. Different tasks and analysis methods are typically used in various experiments, making the comparison of the results across studies arduous. To fill this gap we propose here a new tool for assessing singing proficiency (the Sung Performance Battery, SPB). The SPB starts from the assessment of participants' vocal range followed by five tasks: (1) single-pitch matching, (2) pitch-interval matching, (3) novel-melody matching, (4) singing from memory of familiar melodies (with lyrics and on a syllable), and (5) singing of familiar melodies (with lyrics and on a syllable) at a slow tempo indicated by a metronome. Data analysis via acoustical methods provides objective measures of pitch accuracy and precision in terms of absolute and relative pitch. The SPB has been tested in a group of 50 occasional singers. The results indicate that the battery is useful for characterizing proficient singing and for detecting cases of inaccurate and/or imprecise singing. PMID:24151475

Learning of pitch and time structures in an artificial grammar setting.

Science.gov (United States)

Prince, Jon B; Stevens, Catherine J; Jones, Mari Riess; Tillmann, Barbara

2018-04-12

Despite the empirical evidence for the power of the cognitive capacity of implicit learning of structures and regularities in several modalities and materials, it remains controversial whether implicit learning extends to the learning of temporal structures and regularities. We investigated whether (a) an artificial grammar can be learned equally well when expressed in duration sequences as when expressed in pitch sequences, (b) learning of the artificial grammar in either duration or pitch (as the primary dimension) sequences can be influenced by the properties of the secondary dimension (invariant vs. randomized), and (c) learning can be boosted when the artificial grammar is expressed in both pitch and duration. After an exposure phase with grammatical sequences, learning in a subsequent test phase was assessed in a grammaticality judgment task. Participants in both the pitch and duration conditions showed incidental (not fully implicit) learning of the artificial grammar when the secondary dimension was invariant, but randomizing the pitch sequence prevented learning of the artificial grammar in duration sequences. Expressing the artificial grammar in both pitch and duration resulted in disproportionately better performance, suggesting an interaction between the learning of pitch and temporal structure. The findings are relevant to research investigating the learning of temporal structures and the learning of structures presented simultaneously in 2 dimensions (e.g., space and time, space and objects). By investigating learning, the findings provide further insight into the potential specificity of pitch and time processing, and their integrated versus independent processing, as previously debated in music cognition research. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Contributions of pitch contour, tonality, rhythm, and meter to melodic similarity.

Science.gov (United States)

Prince, Jon B

2014-12-01

The identity of a melody resides in its sequence of pitches and durations, both of which exhibit surface details as well as structural properties. In this study, pitch contour (pattern of ups and downs) served as pitch surface information, and tonality (musical key) as pitch structure; in the temporal dimension, surface information was the ordinal duration ratios of adjacent notes (rhythm), and meter (beat, or pulse) comprised the structure. Factorially manipulating the preservation or alteration of all of these forms of information in 17 novel melodies (typifying Western music) enabled measuring their effect on perceived melodic similarity. In Experiment 1, 34 participants (varied musical training) rated the perceived similarity of melody pairs transposed to new starting pitches. Rhythm was the largest contributor to perceived similarity, then contour, meter, and tonality. Experiment 2 used the same melodies but varied the tempo within a pair, and added a prefix of 3 chords, which oriented the listener to the starting pitch and tempo before the melody began. Now contour was the strongest influence on similarity ratings, followed by tonality, and then rhythm; meter was not significant. Overall, surface features influenced perceived similarity more than structural, but both had observable effects. The primary theoretical advances in melodic similarity research are that (a) the relative emphasis on pitch and temporal factors is flexible; (b) pitch and time functioned independently when factorially manipulated, regardless of which dimension is more influential; and (c) interactions between surface and structural information were unreliable and never occurred between dimensions. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Uncovering phenotypes of poor-pitch singing: The Sung Performance Battery (SPB

Directory of Open Access Journals (Sweden)

Magdalena eBerkowska

2013-10-01

Full Text Available Singing is as natural as speaking for humans. Increasing evidence shows that the layman can carry a tune (e.g., when asked to sing a well-known song or to imitate single pitches, intervals and short melodies. Yet, important individual differences exist in the general population with regard to singing proficiency. Some individuals are particularly inaccurate or imprecise in producing or imitating pitch information (poor-pitch singers, thus showing a variety of singing phenotypes. Unfortunately, so far there is not a standard set of tasks for assessing singing proficiency in the general population, allowing to uncover and characterize individual profiles of poor-pitch singing. Different tasks and analysis methods are typically used in various experiments, making the comparison of the results across studies arduous. To fill this gap we propose here a new tool for assessing singing proficiency (the Sung Performance Battery, SPB. The SPB starts from the assessment of participants’ vocal range followed by five tasks: 1 single-pitch matching, 2 pitch-interval matching, 3 novel-melody matching, 4 singing from memory of familiar melodies (with lyrics and on a syllable, and 5 singing of familiar melodies (with lyrics and on a syllable at a slow tempo indicated by a metronome. Data analysis via acoustical methods provides objective measures of pitch accuracy and precision in terms of absolute and relative pitch. The SPB has been tested in a group of 50 occasional singers. The results indicate that the battery is useful for characterizing proficient singing and for detecting cases of inaccurate and/or imprecise singing.

The Association Between Pitch Conditions and the Incidence of ...

African Journals Online (AJOL)

shown to influence incidence of rugby injuries. Harsh weather conditions and detrimental effect on poor Kenyan rugby pitches create a unique environment for injury exposure. We conducted a whole population prospective cohort study to determine the association of pitch conditions with injury incidence and severity.

PRODUCTION OF FOAMS, FIBERS AND PITCHES USING A COAL EXTRACTION PROCESS

Energy Technology Data Exchange (ETDEWEB)

Chong Chen; Elliot B. Kennel; Liviu Magean; Pete G. Stansberry; Alfred H. Stiller; John W. Zondlo

2004-06-20

This Department of Energy National Energy Technology Laboratory sponsored project developed processes for converting coal feedstocks to carbon products, including coal-derived pitch, coke foams and fibers based on solvent extraction processes. A key technology is the use of hydrogenation accomplished at elevated temperatures and pressures to obtain a synthetic coal pitch. Hydrogenation, or partial direct liquefaction of coal, is used to modify the properties of raw coal such that a molten synthetic pitch can be obtained. The amount of hydrogen required to produce a synthetic pitch is about an order of magnitude less than the amount required to produce synthetic crude oil. Hence the conditions for synthetic pitch production consume very little hydrogen and can be accomplished at substantially lower pressure. In the molten state, hot filtration or centrifugation can be used to separate dissolved coal chemicals from mineral matter and insolubles (inertinite), resulting in the production of a purified hydrocarbon pitch. Alternatively, if hydrogenation is not used, aromatic hydrocarbon liquids appropriate for use as precursors to carbon products can obtained by dissolving coal in a solvent. As in the case for partial direct liquefaction pitches, undissolved coal is removed via hot filtration or centrifugation. Excess solvent is boiled off and recovered. The resultant solid material, referred to as Solvent Extracted Carbon Ore or SECO, has been used successfully to produce artificial graphite and carbon foam.

Nonlinear bounce resonances between magnetosonic waves and equatorially mirroring electrons

Science.gov (United States)

Chen, Lunjin; Maldonado, Armando; Bortnik, Jacob; Thorne, Richard M.; Li, Jinxing; Dai, Lei; Zhan, Xiaoya

2015-08-01

Equatorially mirroring energetic electrons pose an interesting scientific problem, since they generally cannot resonate with any known plasma waves and hence cannot be scattered down to lower pitch angles. Observationally it is well known that the flux of these equatorial particles does not simply continue to build up indefinitely, and so a mechanism must necessarily exist that transports these particles from an equatorial pitch angle of 90° down to lower values. However, this mechanism has not been uniquely identified yet. Here we investigate the mechanism of bounce resonance with equatorial noise (or fast magnetosonic waves). A test particle simulation is used to examine the effects of monochromatic magnetosonic waves on the equatorially mirroring energetic electrons, with a special interest in characterizing the effectiveness of bounce resonances. Our analysis shows that bounce resonances can occur at the first three harmonics of the bounce frequency (nωb, n = 1, 2, and 3) and can effectively reduce the equatorial pitch angle to values where resonant scattering by whistler mode waves becomes possible. We demonstrate that the nature of bounce resonance is nonlinear, and we propose a nonlinear oscillation model for characterizing bounce resonances using two key parameters, effective wave amplitude à and normalized wave number k~z. The threshold for higher harmonic resonance is more strict, favoring higher à and k~z, and the change in equatorial pitch angle is strongly controlled by k~z. We also investigate the dependence of bounce resonance effects on various physical parameters, including wave amplitude, frequency, wave normal angle and initial phase, plasma density, and electron energy. It is found that the effect of bounce resonance is sensitive to the wave normal angle. We suggest that the bounce resonant interaction might lead to an observed pitch angle distribution with a minimum at 90°.

Singing with yourself: evidence for an inverse modeling account of poor-pitch singing.

Science.gov (United States)

Pfordresher, Peter Q; Mantell, James T

2014-05-01

Singing is a ubiquitous and culturally significant activity that humans engage in from an early age. Nevertheless, some individuals - termed poor-pitch singers - are unable to match target pitches within a musical semitone while singing. In the experiments reported here, we tested whether poor-pitch singing deficits would be reduced when individuals imitate recordings of themselves as opposed to recordings of other individuals. This prediction was based on the hypothesis that poor-pitch singers have not developed an abstract "inverse model" of the auditory-vocal system and instead must rely on sensorimotor associations that they have experienced directly, which is true for sequences an individual has already produced. In three experiments, participants, both accurate and poor-pitch singers, were better able to imitate sung recordings of themselves than sung recordings of other singers. However, this self-advantage was enhanced for poor-pitch singers. These effects were not a byproduct of self-recognition (Experiment 1), vocal timbre (Experiment 2), or the absolute pitch of target recordings (i.e., the advantage remains when recordings are transposed, Experiment 3). Results support the conceptualization of poor-pitch singing as an imitative deficit resulting from a deficient inverse model of the auditory-vocal system with respect to pitch. Copyright © 2014 Elsevier Inc. All rights reserved.

Thermal transformations of pitch and its compositions with thermoanthracite

Energy Technology Data Exchange (ETDEWEB)

Belkina, T.V.; Ulanovskii, M.L.; Krysin, V.P.

1983-01-01

Derivatogrphy is used to investigate the character of thermal transformations of hard coal pitch in compositions with thermoanthracite. It was shown that losses in mass during thermal transformations of hard coal pitch in the temperature interval 200-1000 C occur in two stages, at a varying rate in the 200-600 C range and at a constant rate in the 600-1000 C range. The rate of loss in the 200-600 C range is determined primarily by the rate of diffusion of volatile components and products of pitch conversion and in the 600-1000 C range mainly by the rate of the elemental chemical event. The thermal transformation is essentially unchanged in the presence of thermoanthracite. Silica intensifies the synthesis and increases the solid residue yield. Increasing the rate of heating of the pitch-thermoanthracite brings about incomplete separation of volatile products and a corresponding increase in the solid residue yield. (9 refs.)

Embedded pitch adapters for the ATLAS Tracker Upgrade

International Nuclear Information System (INIS)

Ullan, Miguel; Benitez, Victor; Pellegrini, Giulio; Fleta, Celeste; Lozano, Manuel; Lacasta, Carlos; Soldevila, Urmila; Garcia, Carmen

2013-01-01

In the current ATLAS tracker modules, sensor bonding pads are placed on their corresponding strips and oriented along the strips. This creates a difference in pitch and orientation between sensor bond pads and readout electronics bond pads. Therefore, a pitch adapter (PA), or “fan-in”, is needed. The purpose of these PA is the electrical interconnection of every channel from the detector bonding pads to the read-out chips, adapting the different pad pitch. Our new approach is to build those PAs inside the sensor; this is what we call Embedded Pitch Adapters. The idea is to use an additional metal layer in order to define a new group of pads, connected to the strips via tracks with the second metal. The embedded PAs have been fabricated on 4-in. prototype sensors for the ATLAS-Upgrade Endcap Tracker to test their performance and suitability. The tests confirm proper fabrication of the second metal tracks, and no effects on detector performance. No indication of cross-talk between first and second metal channels has been observed. A small indication of possible signal pick-up from the bulk has been observed in a few channels, which needs to be further investigated

Presidential, But Not Prime Minister, Candidates With Lower Pitched Voices Stand a Better Chance of Winning the Election in Conservative Countries.

Science.gov (United States)

Banai, Benjamin; Laustsen, Lasse; Banai, Irena Pavela; Bovan, Kosta

2018-01-01

Previous studies have shown that voters rely on sexually dimorphic traits that signal masculinity and dominance when they choose political leaders. For example, voters exert strong preferences for candidates with lower pitched voices because these candidates are perceived as stronger and more competent. Moreover, experimental studies demonstrate that conservative voters, more than liberals, prefer political candidates with traits that signal dominance, probably because conservatives are more likely to perceive the world as a threatening place and to be more attentive to dangerous and threatening contexts. In light of these findings, this study investigates whether country-level ideology influences the relationship between candidate voice pitch and electoral outcomes of real elections. Specifically, we collected voice pitch data for presidential and prime minister candidates, aggregate national ideology for the countries in which the candidates were nominated, and measures of electoral outcomes for 69 elections held across the world. In line with previous studies, we found that candidates with lower pitched voices received more votes and had greater likelihood of winning the elections. Furthermore, regression analysis revealed an interaction between candidate voice pitch, national ideology, and election type (presidential or parliamentary). That is, having a lower pitched voice was a particularly valuable asset for presidential candidates in conservative and right-leaning countries (in comparison to presidential candidates in liberal and left-leaning countries and parliamentary elections). We discuss the practical implications of these findings, and how they relate to existing research on candidates' voices, voting preferences, and democratic elections in general.

Learning for pitch and melody discrimination in congenital amusia.

Science.gov (United States)

Whiteford, Kelly L; Oxenham, Andrew J

2018-03-23

Congenital amusia is currently thought to be a life-long neurogenetic disorder in music perception, impervious to training in pitch or melody discrimination. This study provides an explicit test of whether amusic deficits can be reduced with training. Twenty amusics and 20 matched controls participated in four sessions of psychophysical training involving either pure-tone (500 Hz) pitch discrimination or a control task of lateralization (interaural level differences for bandpass white noise). Pure-tone pitch discrimination at low, medium, and high frequencies (500, 2000, and 8000 Hz) was measured before and after training (pretest and posttest) to determine the specificity of learning. Melody discrimination was also assessed before and after training using the full Montreal Battery of Evaluation of Amusia, the most widely used standardized test to diagnose amusia. Amusics performed more poorly than controls in pitch but not localization discrimination, but both groups improved with practice on the trained stimuli. Learning was broad, occurring across all three frequencies and melody discrimination for all groups, including those who trained on the non-pitch control task. Following training, 11 of 20 amusics no longer met the global diagnostic criteria for amusia. A separate group of untrained controls (n = 20), who also completed melody discrimination and pretest, improved by an equal amount as trained controls on all measures, suggesting that the bulk of learning for the control group occurred very rapidly from the pretest. Thirty-one trained participants (13 amusics) returned one year later to assess long-term maintenance of pitch and melody discrimination. On average, there was no change in performance between posttest and one-year follow-up, demonstrating that improvements on pitch- and melody-related tasks in amusics and controls can be maintained. The findings indicate that amusia is not always a life-long deficit when using the current standard

179 Extraction of Coal-tar Pitch by Supercritical Carbon Dioxide ...

African Journals Online (AJOL)

Meyer

Several extractions of coal-tar pitch were performed using supercritical fluid ..... pressure and temperature, unlike exhaustive extraction, which involves a change in ... mechanism that is operative on extracting coal-tar pitch components with.

A word by any other intonation: fMRI evidence for implicit memory traces for pitch contours of spoken words in adult brains.

Directory of Open Access Journals (Sweden)

Michael Inspector

Full Text Available OBJECTIVES: Intonation may serve as a cue for facilitated recognition and processing of spoken words and it has been suggested that the pitch contour of spoken words is implicitly remembered. Thus, using the repetition suppression (RS effect of BOLD-fMRI signals, we tested whether the same spoken words are differentially processed in language and auditory brain areas depending on whether or not they retain an arbitrary intonation pattern. EXPERIMENTAL DESIGN: Words were presented repeatedly in three blocks for passive and active listening tasks. There were three prosodic conditions in each of which a different set of words was used and specific task-irrelevant intonation changes were applied: (i All words presented in a set flat monotonous pitch contour (ii Each word had an arbitrary pitch contour that was set throughout the three repetitions. (iii Each word had a different arbitrary pitch contour in each of its repetition. PRINCIPAL FINDINGS: The repeated presentations of words with a set pitch contour, resulted in robust behavioral priming effects as well as in significant RS of the BOLD signals in primary auditory cortex (BA 41, temporal areas (BA 21 22 bilaterally and in Broca's area. However, changing the intonation of the same words on each successive repetition resulted in reduced behavioral priming and the abolition of RS effects. CONCLUSIONS: Intonation patterns are retained in memory even when the intonation is task-irrelevant. Implicit memory traces for the pitch contour of spoken words were reflected in facilitated neuronal processing in auditory and language associated areas. Thus, the results lend support for the notion that prosody and specifically pitch contour is strongly associated with the memory representation of spoken words.

Auditory processing in absolute pitch possessors

Science.gov (United States)

McKetton, Larissa; Schneider, Keith A.

2018-05-01

Absolute pitch (AP) is a rare ability in classifying a musical pitch without a reference standard. It has been of great interest to researchers studying auditory processing and music cognition since it is seldom expressed and sheds light on influences pertaining to neurodevelopmental biological predispositions and the onset of musical training. We investigated the smallest frequency that could be detected or just noticeable difference (JND) between two pitches. Here, we report significant differences in JND thresholds in AP musicians and non-AP musicians compared to non-musician control groups at both 1000 Hz and 987.76 Hz testing frequencies. Although the AP-musicians did better than non-AP musicians, the difference was not significant. In addition, we looked at neuro-anatomical correlates of musicianship and AP using structural MRI. We report increased cortical thickness of the left Heschl's Gyrus (HG) and decreased cortical thickness of the inferior frontal opercular gyrus (IFO) and circular insular sulcus volume (CIS) in AP compared to non-AP musicians and controls. These structures may therefore be optimally enhanced and reduced to form the most efficient network for AP to emerge.

Individual blade pitch for yaw control

International Nuclear Information System (INIS)

Navalkar, S T; Van Wingerden, J W; Van Kuik, G A M

2014-01-01

Individual pitch control (IPC) for reducing blade loads has been investigated and proven successful in recent literature. For IPC, the multi-blade co-ordinate (MBC) transformation is used to process the blade load signals from the rotating to a stationary frame of reference. In the stationary frame of reference, the yaw error of a turbine can be appended to generate IPC actions that are able to achieve turbine yaw control for a turbine in free yaw. In this paper, IPC for yaw control is tested on a high-fidelity numerical model of a commercially produced wind turbine in free yaw. The tests show that yaw control using IPC has the distinct advantage that the yaw system loads and support structure loading are substantially reduced. However, IPC for yaw control also shows a reduction in IPC blade load reduction potential and causes a slight increase in pitch activity. Thus, the key contribution of this paper is the concept demonstration of IPC for yaw control. Further, using IPC for yaw as a tuning parameter, it is shown how the best trade-off between blade loading, pitch activity and support structure loading can be achieved for wind turbine design

Detection and identification of monaural and binaural pitch contours in dyslexic listeners

DEFF Research Database (Denmark)

Santurette, Sébastien; Poelmans, Hanne; Luts, Heleen

2010-01-01

of dyslexic listeners to Huggins' pitch (HP). The present study clarified whether impaired binaural pitch perception is found in dyslexia. Results from a pitch contour identification test, performed in 31 dyslexic listeners and 31 matched controls, clearly showed that dyslexics perceived HP as well...

Full field image reconstruction is suitable for high-pitch dual-source computed tomography.

Science.gov (United States)

Mahnken, Andreas H; Allmendinger, Thomas; Sedlmair, Martin; Tamm, Miriam; Reinartz, Sebastian D; Flohr, Thomas

2012-11-01

The field of view (FOV) in high-pitch dual-source computed tomography (DSCT) is limited by the size of the second detector. The goal of this study was to develop and evaluate a full FOV image reconstruction technique for high-pitch DSCT. For reconstruction beyond the FOV of the second detector, raw data of the second system were extended to the full dimensions of the first system, using the partly existing data of the first system in combination with a very smooth transition weight function. During the weighted filtered backprojection, the data of the second system were applied with an additional weighting factor. This method was tested for different pitch values from 1.5 to 3.5 on a simulated phantom and on 25 high-pitch DSCT data sets acquired at pitch values of 1.6, 2.0, 2.5, 2.8, and 3.0. Images were reconstructed with FOV sizes of 260 × 260 and 500 × 500 mm. Image quality was assessed by 2 radiologists using a 5-point Likert scale and analyzed with repeated-measure analysis of variance. In phantom and patient data, full FOV image quality depended on pitch. Where complete projection data from both tube-detector systems were available, image quality was unaffected by pitch changes. Full FOV image quality was not compromised at pitch values of 1.6 and remained fully diagnostic up to a pitch of 2.0. At higher pitch values, there was an increasing difference in image quality between limited and full FOV images (P = 0.0097). With this new image reconstruction technique, full FOV image reconstruction can be used up to a pitch of 2.0.

Development of a micromechanical pitch-tunable grating with reflective/transmissive dual working modes

International Nuclear Information System (INIS)

Yu, Yi-Ting; Yuan, Wei-Zheng; Li, Tai-Ping; Yan, Bin

2010-01-01

In this paper, a micromechanical pitch-tunable grating with the capability of working in both reflective and transmissive modes is developed by using the silicon-on-glass (SOG) process. At a voltage of 65 V, the grating period is measured to increase by 4.62%. A simple optical experiment is performed to demonstrate how the proposed grating works in both modes. Then, experiments to measure the change of the diffraction angle versus driving voltage in both reflective and transmissive modes are designed and carried out utilizing an area-arrayed charge-coupled device (CCD), and the results are in good agreement with the theoretical calculation. Discussions on the structural configuration and diffraction efficiency of the proposed grating are presented. The grating presented provides better flexibility in the design and development of application systems.

Sparse Multi-Pitch and Panning Estimation of Stereophonic Signals

DEFF Research Database (Denmark)

Kronvall, Ted; Jakobsson, Andreas; Hansen, Martin Weiss

2016-01-01

In this paper, we propose a novel multi-pitch estimator for stereophonic mixtures, allowing for pitch estimation on multi-channel audio even if the amplitude and delay panning parameters are unknown. The presented method does not require prior knowledge of the number of sources present in the mix...

Investigation of load reduction for a variable speed, variable pitch, and variable coning wind turbine

Energy Technology Data Exchange (ETDEWEB)

Pierce, K. [Univ. of Utah, Salt Lake City, UT (United States)

1997-12-31

A two bladed, variable speed and variable pitch wind turbine was modeled using ADAMS{reg_sign} to evaluate load reduction abilities of a variable coning configuration as compared to a teetered rotor, and also to evaluate control methods. The basic dynamic behavior of the variable coning turbine was investigated and compared to the teetered rotor under constant wind conditions as well as turbulent wind conditions. Results indicate the variable coning rotor has larger flap oscillation amplitudes and much lower root flap bending moments than the teetered rotor. Three methods of control were evaluated for turbulent wind simulations. These were a standard IPD control method, a generalized predictive control method, and a bias estimate control method. Each control method was evaluated for both the variable coning configuration and the teetered configuration. The ability of the different control methods to maintain the rotor speed near the desired set point is evaluated from the RMS error of rotor speed. The activity of the control system is evaluated from cycles per second of the blade pitch angle. All three of the methods were found to produce similar results for the variable coning rotor and the teetered rotor, as well as similar results to each other.

Investigation of habitual pitch during free play activities for preschool-aged children.

Science.gov (United States)

Chen, Yang; Kimelman, Mikael D Z; Micco, Katie

2009-01-01

This study is designed to compare the habitual pitch measured in two different speech activities (free play activity and traditionally used structured speech activity) for normally developing preschool-aged children to explore to what extent preschoolers vary their vocal pitch among different speech environments. Habitual pitch measurements were conducted for 10 normally developing children (2 boys, 8 girls) between the ages of 31 months and 71 months during two different activities: (1) free play; and (2) structured speech. Speech samples were recorded using a throat microphone connected with a wireless transmitter in both activities. The habitual pitch (in Hz) was measured for all collected speech samples by using voice analysis software (Real-Time Pitch). Significantly higher habitual pitch is found during free play in contrast to structured speech activities. In addition, there is no showing of significant difference of habitual pitch elicited across a variety of structured speech activities. Findings suggest that the vocal usage of preschoolers appears to be more effortful during free play than during structured activities. It is recommended that a comprehensive evaluation for young children's voice needs to be based on the speech/voice samples collected from both free play and structured activities.

Frogs Call at a Higher Pitch in Traffic Noise

Directory of Open Access Journals (Sweden)

Kirsten M. Parris

2009-06-01

Full Text Available Male frogs call to attract females for mating and to defend territories from rival males. Female frogs of some species prefer lower-pitched calls, which indicate larger, more experienced males. Acoustic interference occurs when background noise reduces the active distance or the distance over which an acoustic signal can be detected. Birds are known to call at a higher pitch or frequency in urban noise, decreasing acoustic interference from low-frequency noise. Using Bayesian linear regression, we investigated the effect of traffic noise on the pitch of advertisement calls in two species of frogs, the southern brown tree frog (Litoria ewingii and the common eastern froglet (Crinia signifera. We found evidence that L. ewingii calls at a higher pitch in traffic noise, with an average increase in dominant frequency of 4.1 Hz/dB of traffic noise, and a total effect size of 123 Hz. This frequency shift is smaller than that observed in birds, but is still large enough to be detected by conspecific frogs and confer a significant benefit to the caller. Mathematical modelling predicted a 24% increase in the active distance of a L. ewingii call in traffic noise with a frequency shift of this size. Crinia signifera may also call at a higher pitch in traffic noise, but more data are required to be confident of this effect. Because frog calls are innate rather than learned, the frequency shift demonstrated by L. ewingii may represent an evolutionary adaptation to noisy conditions. The phenomenon of frogs calling at a higher pitch in traffic noise could therefore constitute an intriguing trade-off between audibility and attractiveness to potential mates.

Fine-pitch glass GEM for high-resolution X-ray imaging

International Nuclear Information System (INIS)

Fujiwara, T.; Toyokawa, H.; Mitsuya, Y.

2016-01-01

We have developed a fine-pitch glass gas electron multiplier (G-GEM) for high-resolution X-ray imaging. The fine-pitch G-GEM is made of a 400 μm thick photo-etchable glass substrate with 150 μm pitch holes. It is fabricated using the same wet etching technique as that for the standard G-GEM. In this work, we present the experimental results obtained with a single fine-pitch G-GEM with a 50 × 50 mm 2 effective area. We recorded an energy resolution of 16.2% and gas gain up to 5,500 when the detector was irradiated with 5.9 keV X-rays. We present a 50 × 50 mm 2 X-ray radiograph image acquired with a scintillation gas and optical readout system.

Pitch Channel Control of a REMUS AUV with Input Saturation and Coupling Disturbances

Directory of Open Access Journals (Sweden)

Nailong Wu

2018-02-01

Full Text Available The motion of an underwater vehicle is prone to be affected by time-varying model parameters and the actuator limitation in control practice. Adaptive control is an effective method to deal with the general system dynamic uncertainties and disturbances. However, the effect of disturbances control on transient dynamics is not prominent. In this paper, we redesign the L 1 adaptive control architecture (L1AC with anti-windup (AW compensator to guarantee robust and fast adaption of the underwater vehicle with input saturation and coupling disturbances. To reduce the fluctuation of vehicle states, the Riccati-based AW compensator is utilized to compensate the output signal from L1AC controller via taking proper modification. The proposed method is applied to the pitch channel of REMUS vehicle’s six Degrees Of Freedom (DOF model with strong nonlinearities and compared with L1AC baseline controller. Simulations show the effectiveness of the proposed control strategy compared to the original L1AC. Besides, the fluctuation in roll channel coupled with pitch channel is suppressed according to the performances of control tests.

Congenital amusia (or tone-deafness interferes with pitch processing in tone languages

Directory of Open Access Journals (Sweden)

Barbara eTillmann

2011-06-01

Full Text Available Congenital amusia is a neurogenetic disorder that affects music processing and that is ascribed to a deficit in pitch processing. We investigated whether this deficit extended to pitch processing in speech, notably the pitch changes used to contrast lexical tones in tonal languages. Congenital amusics and matched controls, all non-tonal language speakers, were tested for lexical tone discrimination in Mandarin Chinese (Experiment 1 and in Thai (Experiment 2. Tones were presented in pairs and participants were required to make same/different judgments. Experiment 2 additionally included musical analogs of Thai tones for comparison. Performance of congenital amusics was inferior to that of controls for all materials, suggesting a domain-general pitch-processing deficit. The pitch deficit of amusia is thus not limited to music, but may compromise the ability to process and learn tonal languages. Combined with acoustic analyses of the tone material, the present findings provide new insights into the nature of the pitch-processing deficit exhibited by amusics.

Congenital Amusia (or Tone-Deafness) Interferes with Pitch Processing in Tone Languages.

Science.gov (United States)

Tillmann, Barbara; Burnham, Denis; Nguyen, Sebastien; Grimault, Nicolas; Gosselin, Nathalie; Peretz, Isabelle

2011-01-01

Congenital amusia is a neurogenetic disorder that affects music processing and that is ascribed to a deficit in pitch processing. We investigated whether this deficit extended to pitch processing in speech, notably the pitch changes used to contrast lexical tones in tonal languages. Congenital amusics and matched controls, all non-tonal language speakers, were tested for lexical tone discrimination in Mandarin Chinese (Experiment 1) and in Thai (Experiment 2). Tones were presented in pairs and participants were required to make same/different judgments. Experiment 2 additionally included musical analogs of Thai tones for comparison. Performance of congenital amusics was inferior to that of controls for all materials, suggesting a domain-general pitch-processing deficit. The pitch deficit of amusia is thus not limited to music, but may compromise the ability to process and learn tonal languages. Combined with acoustic analyses of the tone material, the present findings provide new insights into the nature of the pitch-processing deficit exhibited by amusics.

Fundamental study on aerodynamic force of floating offshore wind turbine with cyclic pitch mechanism

International Nuclear Information System (INIS)

Li, Qing'an; Kamada, Yasunari; Maeda, Takao; Murata, Junsuke; Iida, Kohei; Okumura, Yuta

2016-01-01

Wind turbines mounted on floating platforms are subjected to completely different and soft foundation properties, rather than onshore wind turbines. Due to the flexibility of their mooring systems, floating offshore wind turbines are susceptible to large oscillations such as aerodynamic force of the wind and hydrodynamic force of the wave, which may compromise their performance and structural stability. This paper focuses on the evaluation of aerodynamic forces depending on suppressing undesired turbine's motion by a rotor thrust control which is controlled by pitch changes with wind tunnel experiments. In this research, the aerodynamic forces of wind turbine are tested at two kinds of pitch control system: steady pitch control and cyclic pitch control. The rotational speed of rotor is controlled by a variable speed generator, which can be measured by the power coefficient. Moment and force acts on model wind turbine are examined by a six-component balance. From cyclic pitch testing, the direction and magnitude of moment can be arbitrarily controlled by cyclic pitch control. Moreover, the fluctuations of thrust coefficient can be controlled by collective pitch control. The results of this analysis will help resolve the fundamental design of suppressing undesired turbine's motion by cyclic pitch control. - Highlights: • Offshore wind offers additional options in regions with low onshore potential. • Two kinds of pitch control system: Steady pitch control and Cyclic pitch control. • Performance curves and unsteady aerodynamics are investigated in wind tunnel. • Fluctuations of thrust coefficient can be controlled by collective pitch control.

A Fröhlich effect and representational gravity in memory for auditory pitch.

Science.gov (United States)

Hubbard, Timothy L; Ruppel, Susan E

2013-08-01

Memory for the initial pitch of an auditory target that increased or decreased in auditory frequency was examined. Memory was displaced forward in the direction of pitch motion, and this is consistent with the Fröhlich effect previously observed for visual targets moving in visual physical space. The Fröhlich effect for pitch increased with faster target velocity and decreased if an auditory cue with the same pitch as the initial pitch of the target was presented before the target was presented. The Fröhlich effect was larger for descending pitch motion than for ascending pitch motion, and this is consistent with an influence of representational gravity. The data suggest that representation of auditory frequency space exhibits some of the same biases as representation of visual physical space, and implications for theories of attention in displacement and for crossmodal and multisensory representation of space are discussed. 2013 APA, all rights reserved

The effects of medial ulnar collateral ligament reconstruction on Major League pitching performance.

Science.gov (United States)

Keller, Robert A; Steffes, Matthew J; Zhuo, David; Bey, Michael J; Moutzouros, Vasilios

2014-11-01

Medial ulnar collateral ligament (MUCL) reconstruction is commonly performed on Major League Baseball (MLB) pitchers. Previous studies have reported that most pitchers return to presurgical statistical performance levels after MUCL reconstruction. Pitching performance data--specifically, earned run average (ERA), walks and hits per inning pitched (WHIP), winning percentage, and innings pitched--were acquired for 168 MLB pitchers who had undergone MUCL reconstruction. These data were averaged over the 3 years before surgery and the 3 years after surgery and also acquired from 178 age-matched, uninjured MLB pitchers. Of the pitchers who had MUCL reconstruction surgery, 87% returned to MLB pitching. However, compared with presurgical data, pitching performance declined in terms of ERA (P = .001), WHIP (P = .011), and innings pitched (P = .026). Pitching performance also declined in the season before the surgery compared with previous years (ERA, P = .014; WHIP, P = .036; innings pitched, P risk factor for requiring surgery. In addition, there is an increased risk of MUCL reconstruction for pitchers who enter the major leagues at a younger age. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Pitch Perception, Working Memory, and Second-Language Phonological Production

Science.gov (United States)

Posedel, James; Emery, Lisa; Souza, Benjamin; Fountain, Catherine

2012-01-01

Previous research has suggested that training on a musical instrument is associated with improvements in working memory and musical pitch perception ability. Good working memory and musical pitch perception ability, in turn, have been linked to certain aspects of language production. The current study examines whether working memory and/or pitch…

TRUNK LEAN DURING A SINGLE-LEG SQUAT IS ASSOCIATED WITH TRUNK LEAN DURING PITCHING.

Science.gov (United States)