Polarization-direction correlation measurement --- Experimental test of the PDCO methods

NASA Astrophysics Data System (ADS)

Starosta, K.; Morek, T.; Droste, Ch.; Rohoziński, S. G.; Srebrny, J.; Bergstrem, M.; Herskind, B.

1998-04-01

Information about spins and parities of excited states is crucial for nuclear structure studies. In ``in-beam" gamma ray spectroscopy the directional correlation (DCO) or angular distribution measurements are widely used tools for multipolarity assignment; although, it is known that neither of these methods is sensitive to electric or magnetic character of gamma radiation. Multipolarity of gamma rays may be determined when the results of the DCO analysis are combined with the results of linear polarization measurements. The large total efficiency of modern multidetector arrays allows one to carry out coincidence measurements between the polarimeter and the remaining detectors. The aim of the present study was to test experimentally the possibility of polarization-direction correlation measurements using the EUROGAM II array. The studied nucleus was ^164Yb produced in the ^138Ba(^30Si,4n) reaction at beam energies of 150 and 155 MeV. The angular correlation, linear polarization and direction-polarization correlation were measured for the strong transitions in yrast and non yrast cascades. Application of the PDCO analysis to a transition connecting a side band with the yrast band allowed one to rule out most of the ambiguities in multipolarity assignment occuring if one used angular correlations only.

Experimental test of the polarization direction correlation method (PDCO)

NASA Astrophysics Data System (ADS)

Starosta, K.; Morek, T.; Droste, Ch.; Rohoziński, S. G.; Srebrny, J.; Wierzchucka, A.; Bergström, M.; Herskind, B.; Melby, E.; Czosnyka, T.; Napiorkowski, P. J.

1999-02-01

The study of the polarization direction correlation method (PDCO) for γ quanta emitted from the nuclear states oriented in fusion-evaporation reactions is discussed with emphasis on making unique multipolarity assignments. The method is applied to the data coming from a typical experiment performed with the EUROGAM II array, where polarization-sensitive CLOVER detectors were used. The accuracy obtained in the experiment for the studied transitions was high enough to exclude, using the PDCO method, most of the ambiguities which occur if the assignments are made on the basis of angular correlation measurements alone.

Modelling the angular correlation function and its full covariance in photometric galaxy surveys

NASA Astrophysics Data System (ADS)

Crocce, Martín; Cabré, Anna; Gaztañaga, Enrique

2011-06-01

Near-future cosmology will see the advent of wide-area photometric galaxy surveys, such as the Dark Energy Survey (DES), that extend to high redshifts (z˜ 1-2) but give poor radial distance resolution. In such cases splitting the data into redshift bins and using the angular correlation function w(θ), or the Cℓ power spectrum, will become the standard approach to extracting cosmological information or to studying the nature of dark energy through the baryon acoustic oscillations (BAO) probe. In this work we present a detailed model for w(θ) at large scales as a function of redshift and binwidth, including all relevant effects, namely non-linear gravitational clustering, bias, redshift space distortions and photo-z uncertainties. We also present a model for the full covariance matrix, characterizing the angular correlation measurements, that takes into account the same effects as for w(θ) and also the possibility of a shot-noise component and partial sky coverage. Provided with a large-volume N-body simulation from the MICE collaboration, we built several ensembles of mock redshift bins with a sky coverage and depth typical of forthcoming photometric surveys. The model for the angular correlation and the one for the covariance matrix agree remarkably well with the mock measurements in all configurations. The prospects for a full shape analysis of w(θ) at BAO scales in forthcoming photometric surveys such as DES are thus very encouraging.

Diverse trends of electron correlation effects for properties with different radial and angular factors in an atomic system: a case study in Ca+

NASA Astrophysics Data System (ADS)

Kumar, Pradeep; Li, Cheng-Bin; Sahoo, B. K.

2018-03-01

Dependencies of electron correlation effects with the rank and radial behavior of spectroscopic properties are analyzed in the singly charged calcium ion (Ca+). To demonstrate these trends, we have determined field shift constants, magnetic dipole and electric quadrupole hyperfine structure constants, Landé g J factors, and electric quadrupole moments that are described by electronic operators with different radial and angular factors. Radial dependencies are investigated by comparing correlation trends among the properties that have similar angular factors and vice versa. To highlight these observations, we present results from the mean-field approach to all-orders along with intermediate contributions. Contributions from higher relativistic corrections are also given. These findings suggest that sometime lower-order approximations can give results agreeing with the experimental results, but inclusion of some of higher-order correlation effects can cause large disagreement with the experimental values. Therefore, validity of a method for accurate evaluation of atomic properties can be tested by performing calculations of several properties simultaneously that have diverse dependencies on the angular and radial factors and comparing with the available experimental results. Nevertheless, it is imperative to include full triple and quadrupole excitations in the all-order many-body methods for high-precision calculations that are yet to be developed adopting spherical coordinate system for atomic studies.

Multiframe super resolution reconstruction method based on light field angular images

NASA Astrophysics Data System (ADS)

Zhou, Shubo; Yuan, Yan; Su, Lijuan; Ding, Xiaomin; Wang, Jichao

2017-12-01

The plenoptic camera can directly obtain 4-dimensional light field information from a 2-dimensional sensor. However, based on the sampling theorem, the spatial resolution is greatly limited by the microlenses. In this paper, we present a method of reconstructing high-resolution images from the angular images. First, the ray tracing method is used to model the telecentric-based light field imaging process. Then, we analyze the subpixel shifts between the angular images extracted from the defocused light field data and the blur in the angular images. According to the analysis above, we construct the observation model from the ideal high-resolution image to the angular images. Applying the regularized super resolution method, we can obtain the super resolution result with a magnification ratio of 8. The results demonstrate the effectiveness of the proposed observation model.

CFHTLenS and RCSLenS: testing photometric redshift distributions using angular cross-correlations with spectroscopic galaxy surveys

NASA Astrophysics Data System (ADS)

Choi, A.; Heymans, C.; Blake, C.; Hildebrandt, H.; Duncan, C. A. J.; Erben, T.; Nakajima, R.; Van Waerbeke, L.; Viola, M.

2016-12-01

We determine the accuracy of galaxy redshift distributions as estimated from photometric redshift probability distributions p(z). Our method utilizes measurements of the angular cross-correlation between photometric galaxies and an overlapping sample of galaxies with spectroscopic redshifts. We describe the redshift leakage from a galaxy photometric redshift bin j into a spectroscopic redshift bin I using the sum of the p(z) for the galaxies residing in bin j. We can then predict the angular cross-correlation between photometric and spectroscopic galaxies due to intrinsic galaxy clustering when I ≠ j as a function of the measured angular cross-correlation when I = j. We also account for enhanced clustering arising from lensing magnification using a halo model. The comparison of this prediction with the measured signal provides a consistency check on the validity of using the summed p(z) to determine galaxy redshift distributions in cosmological analyses, as advocated by the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). We present an analysis of the photometric redshifts measured by CFHTLenS, which overlaps the Baryon Oscillation Spectroscopic Survey (BOSS). We also analyse the Red-sequence Cluster Lensing Survey, which overlaps both BOSS and the WiggleZ Dark Energy Survey. We find that the summed p(z) from both surveys are generally biased with respect to the true underlying distributions. If unaccounted for, this bias would lead to errors in cosmological parameter estimation from CFHTLenS by less than ˜4 per cent. For photometric redshift bins which spatially overlap in 3D with our spectroscopic sample, we determine redshift bias corrections which can be used in future cosmological analyses that rely on accurate galaxy redshift distributions.

Angular correlation of cosmic neutrinos with ultrahigh-energy cosmic rays and implications for their sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moharana, Reetanjali; Razzaque, Soebur, E-mail: reetanjalim@uj.ac.za, E-mail: srazzaque@uj.ac.za

2015-08-01

Cosmic neutrino events detected by the IceCube Neutrino Observatory with energy 0∼> 3 TeV have poor angular resolutions to reveal their origin. Ultrahigh-energy cosmic rays (UHECRs), with better angular resolutions at 0>6 EeV energies, can be used to check if the same astrophysical sources are responsible for producing both neutrinos and UHECRs. We test this hypothesis, with statistical methods which emphasize invariant quantities, by using data from the Pierre Auger Observatory, Telescope Array and past cosmic-ray experiments. We find that the arrival directions of the cosmic neutrinos are correlated with 0≥ 10 EeV UHECR arrival directions at confidence level ≈ 90%. The strengthmore » of the correlation decreases with decreasing UHECR energy and no correlation exists at energy 0∼ 6 EeV . A search in astrophysical databases within 3{sup o} of the arrival directions of UHECRs with energy 0≥ 10 EeV, that are correlated with the IceCube cosmic neutrinos, resulted in 18 sources from the Swift-BAT X-ray catalog with redshift z≤ 0.06. We also found 3 objects in the Kühr catalog of radio sources using the same criteria. The sources are dominantly Seyfert galaxies with Cygnus A being the most prominent member. We calculate the required neutrino and UHECR fluxes to produce the observed correlated events, and estimate the corresponding neutrino luminosity (25 TeV–2.2 PeV) and cosmic-ray luminosity (500 TeV–180 EeV), assuming the sources are the ones we found in the Swift-BAT and Kühr catalogs. We compare these luminosities with the X-ray luminosity of the corresponding sources and discuss possibilities of accelerating protons to 0∼> 10 EeV and produce neutrinos in these sources.« less

Generalized extended Navier-Stokes theory: correlations in molecular fluids with intrinsic angular momentum.

PubMed

Hansen, J S; Daivis, Peter J; Dyre, Jeppe C; Todd, B D; Bruus, Henrik

2013-01-21

The extended Navier-Stokes theory accounts for the coupling between the translational and rotational molecular degrees of freedom. In this paper, we generalize this theory to non-zero frequencies and wavevectors, which enables a new study of spatio-temporal correlation phenomena present in molecular fluids. To discuss these phenomena in detail, molecular dynamics simulations of molecular chlorine are performed for three different state points. In general, the theory captures the behavior for small wavevector and frequencies as expected. For example, in the hydrodynamic regime and for molecular fluids with small moment of inertia like chlorine, the theory predicts that the longitudinal and transverse intrinsic angular velocity correlation functions are almost identical, which is also seen in the molecular dynamics simulations. However, the theory fails at large wavevector and frequencies. To account for the correlations at these scales, we derive a phenomenological expression for the frequency dependent rotational viscosity and wavevector and frequency dependent longitudinal spin viscosity. From this we observe a significant coupling enhancement between the molecular angular velocity and translational velocity for large frequencies in the gas phase; this is not observed for the supercritical fluid and liquid state points.

Matrix elements of explicitly correlated Gaussian basis functions with arbitrary angular momentum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joyce, Tennesse; Varga, Kálmán

2016-05-14

A new algorithm for calculating the Hamiltonian matrix elements with all-electron explicitly correlated Gaussian functions for quantum-mechanical calculations of atoms with arbitrary angular momentum is presented. The calculations are checked on several excited states of three and four electron systems. The presented formalism can be used as unified framework for high accuracy calculations of properties of small atoms and molecules.

Effect of gold wire bonding process on angular correlated color temperature uniformity of white light-emitting diode.

PubMed

Wu, Bulong; Luo, Xiaobing; Zheng, Huai; Liu, Sheng

2011-11-21

Gold wire bonding is an important packaging process of lighting emitting diode (LED). In this work, we studied the effect of gold wire bonding on the angular uniformity of correlated color temperature (CCT) in white LEDs whose phosphor layers were coated by freely dispersed coating process. Experimental study indicated that different gold wire bonding impacts the geometry of phosphor layer, and it results in different fluctuation trends of angular CCT at different spatial planes in one LED sample. It also results in various fluctuating amplitudes of angular CCT distributions at the same spatial plane for samples with different wire bonding angles. The gold wire bonding process has important impact on angular uniformity of CCT in LED package. © 2011 Optical Society of America

A New Shape Description Method Using Angular Radial Transform

NASA Astrophysics Data System (ADS)

Lee, Jong-Min; Kim, Whoi-Yul

Shape is one of the primary low-level image features in content-based image retrieval. In this paper we propose a new shape description method that consists of a rotationally invariant angular radial transform descriptor (IARTD). The IARTD is a feature vector that combines the magnitude and aligned phases of the angular radial transform (ART) coefficients. A phase correction scheme is employed to produce the aligned phase so that the IARTD is invariant to rotation. The distance between two IARTDs is defined by combining differences in the magnitudes and aligned phases. In an experiment using the MPEG-7 shape dataset, the proposed method outperforms existing methods; the average BEP of the proposed method is 57.69%, while the average BEPs of the invariant Zernike moments descriptor and the traditional ART are 41.64% and 36.51%, respectively.

Attosecond Electron Correlation Dynamics in Double Ionization of Benzene Probed with Two-Electron Angular Streaking

NASA Astrophysics Data System (ADS)

Winney, Alexander H.; Lee, Suk Kyoung; Lin, Yun Fei; Liao, Qing; Adhikari, Pradip; Basnayake, Gihan; Schlegel, H. Bernhard; Li, Wen

2017-09-01

With a novel three-dimensional electron-electron coincidence imaging technique and two-electron angular streaking method, we show that the emission time delay between two electrons can be measured from tens of attoseconds to more than 1 fs. Surprisingly, in benzene, the double ionization rate decays as the time delay between the first and second electron emission increases during the first 500 as. This is further supported by the decay of the Coulomb repulsion in the direction perpendicular to the laser polarization. This result reveals that laser-induced electron correlation plays a major role in strong field double ionization of benzene driven by a nearly circularly polarized field.

A goal-based angular adaptivity method for thermal radiation modelling in non grey media

NASA Astrophysics Data System (ADS)

Soucasse, Laurent; Dargaville, Steven; Buchan, Andrew G.; Pain, Christopher C.

2017-10-01

This paper investigates for the first time a goal-based angular adaptivity method for thermal radiation transport, suitable for non grey media when the radiation field is coupled with an unsteady flow field through an energy balance. Anisotropic angular adaptivity is achieved by using a Haar wavelet finite element expansion that forms a hierarchical angular basis with compact support and does not require any angular interpolation in space. The novelty of this work lies in (1) the definition of a target functional to compute the goal-based error measure equal to the radiative source term of the energy balance, which is the quantity of interest in the context of coupled flow-radiation calculations; (2) the use of different optimal angular resolutions for each absorption coefficient class, built from a global model of the radiative properties of the medium. The accuracy and efficiency of the goal-based angular adaptivity method is assessed in a coupled flow-radiation problem relevant for air pollution modelling in street canyons. Compared to a uniform Haar wavelet expansion, the adapted resolution uses 5 times fewer angular basis functions and is 6.5 times quicker, given the same accuracy in the radiative source term.

Long-Range Near-Side Angular Correlations in Proton-Proton Interactions in CMS.

ScienceCinema

None

2017-12-09

The CMS Collaboration Results on two-particle angular correlations for charged particles emitted in proton-proton collisions at center of mass energies of 0.9, 2.36 and 7TeV over a broad range of pseudorapidity (?) and azimuthal angle (f) are presented using data collected with the CMS detector at the LHC. Short-range correlations in ??, which are studied in minimum bias events, are characterized using a simple independent cluster parameterization in order to quantify their strength (cluster size) and their extent in ? (cluster decay width). Long-range azimuthal correlations are studied more differentially as a function of charged particle multiplicity and particle transverse momentum using a 980nb-1 data set at 7TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particles in intermediate pT’s of 1-3GeV/c, 2.0< |??|<4.8 and ?f˜0. This is the ?rst observation of such a ridge-like feature in two-particle correlation functions in pp or p-pbar collisions. EVO Universe, password "seminar"; Phone Bridge ID: 2330444 Password: 5142

Lensing corrections to features in the angular two-point correlation function and power spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

LoVerde, Marilena; Department of Physics, Columbia University, New York, New York 10027; Hui, Lam

2008-01-15

It is well known that magnification bias, the modulation of galaxy or quasar source counts by gravitational lensing, can change the observed angular correlation function. We investigate magnification-induced changes to the shape of the observed correlation function w({theta}), and the angular power spectrum C{sub l}, paying special attention to the matter-radiation equality peak and the baryon wiggles. Lensing effectively mixes the correlation function of the source galaxies with that of the matter correlation at the lower redshifts of the lenses distorting the observed correlation function. We quantify how the lensing corrections depend on the width of the selection function, themore » galaxy bias b, and the number count slope s. The lensing correction increases with redshift and larger corrections are present for sources with steep number count slopes and/or broad redshift distributions. The most drastic changes to C{sub l} occur for measurements at high redshifts (z > or approx. 1.5) and low multipole moment (l < or approx. 100). For the source distributions we consider, magnification bias can shift the location of the matter-radiation equality scale by 1%-6% at z{approx}1.5 and by z{approx}3.5 the shift can be as large as 30%. The baryon bump in {theta}{sup 2}w({theta}) is shifted by < or approx. 1% and the width is typically increased by {approx}10%. Shifts of > or approx. 0.5% and broadening > or approx. 20% occur only for very broad selection functions and/or galaxies with (5s-2)/b > or approx. 2. However, near the baryon bump the magnification correction is not constant but is a gently varying function which depends on the source population. Depending on how the w({theta}) data is fitted, this correction may need to be accounted for when using the baryon acoustic scale for precision cosmology.« less

B B ¯ angular correlations at the LHC in the parton Reggeization approach merged with higher-order matrix elements

NASA Astrophysics Data System (ADS)

Karpishkov, A. V.; Nefedov, M. A.; Saleev, V. A.

2017-11-01

We calculate the angular distribution spectra between beauty (B ) and antibeauty (B ¯) mesons in proton-proton collisions in the leading order approximation of the parton Reggeization approach consistently merged with the next-to-leading order corrections from the emission of an additional hard gluon. To describe b-quark hadronization we use the universal scale-dependent parton-to-meson fragmentation functions extracted from the world e+e- annihilation data. We have obtained good agreement between our predictions and data from the CMS Collaboration at the energy √{S }=7 TeV for B B ¯ angular correlations within uncertainties and without free parameters. Predictions for analogous correlation observables at √{S }=13 TeV are provided.

Methods for rapidly processing angular masks of next-generation galaxy surveys

NASA Astrophysics Data System (ADS)

Swanson, M. E. C.; Tegmark, Max; Hamilton, Andrew J. S.; Hill, J. Colin

2008-07-01

As galaxy surveys become larger and more complex, keeping track of the completeness, magnitude limit and other survey parameters as a function of direction on the sky becomes an increasingly challenging computational task. For example, typical angular masks of the Sloan Digital Sky Survey contain about N = 300000 distinct spherical polygons. Managing masks with such large numbers of polygons becomes intractably slow, particularly for tasks that run in time with a naive algorithm, such as finding which polygons overlap each other. Here we present a `divide-and-conquer' solution to this challenge: we first split the angular mask into pre-defined regions called `pixels', such that each polygon is in only one pixel, and then perform further computations, such as checking for overlap, on the polygons within each pixel separately. This reduces tasks to , and also reduces the important task of determining in which polygon(s) a point on the sky lies from to , resulting in significant computational speedup. Additionally, we present a method to efficiently convert any angular mask to and from the popular HEALPIX format. This method can be generically applied to convert to and from any desired spherical pixelization. We have implemented these techniques in a new version of the MANGLE software package, which is freely available at http://space.mit.edu/home/tegmark/mangle/, along with complete documentation and example applications. These new methods should prove quite useful to the astronomical community, and since MANGLE is a generic tool for managing angular masks on a sphere, it has the potential to benefit terrestrial mapmaking applications as well.

Scale factor measure method without turntable for angular rate gyroscope

NASA Astrophysics Data System (ADS)

Qi, Fangyi; Han, Xuefei; Yao, Yanqing; Xiong, Yuting; Huang, Yuqiong; Wang, Hua

2018-03-01

In this paper, a scale factor test method without turntable is originally designed for the angular rate gyroscope. A test system which consists of test device, data acquisition circuit and data processing software based on Labview platform is designed. Taking advantage of gyroscope's sensitivity of angular rate, a gyroscope with known scale factor, serves as a standard gyroscope. The standard gyroscope is installed on the test device together with a measured gyroscope. By shaking the test device around its edge which is parallel to the input axis of gyroscope, the scale factor of the measured gyroscope can be obtained in real time by the data processing software. This test method is fast. It helps test system miniaturized, easy to carry or move. Measure quarts MEMS gyroscope's scale factor multi-times by this method, the difference is less than 0.2%. Compare with testing by turntable, the scale factor difference is less than 1%. The accuracy and repeatability of the test system seems good.

Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background

NASA Astrophysics Data System (ADS)

Melia, F.; López-Corredoira, M.

2018-03-01

Aim. The lack of large-angle correlations in the fluctuations of the cosmic microwave background (CMB) conflicts with predictions of slow-roll inflation. But while probabilities (≲0.24%) for the missing correlations disfavour the conventional picture at ≳3σ, factors not associated with the model itself may be contributing to the tension. Here we aim to show that the absence of large-angle correlations is best explained with the introduction of a non-zero minimum wave number kmin for the fluctuation power spectrum P(k). Methods: We assumed that quantum fluctuations were generated in the early Universe with a well-defined power spectrum P(k), although with a cut-off kmin ≠ 0. We then re-calculated the angular correlation function of the CMB and compared it with Planck observations. Results: The Planck 2013 data rule out a zero kmin at a confidence level exceeding 8σ. Whereas purely slow-roll inflation would have stretched all fluctuations beyond the horizon, producing a P(k) with kmin = 0 - and therefore strong correlations at all angles - a kmin ≠ 0 would signal the presence of a maximum wavelength at the time (tdec) of decoupling. This argues against the basic inflationary paradigm, and perhaps even suggests non-inflationary alternatives, for the origin and growth of perturbations in the early Universe. In at least one competing cosmology, the Rh = ct universe, the inferred kmin corresponds to the gravitational radius at tdec.

Euclidean perspective on the unfolding of azurin: angular correlations

NASA Astrophysics Data System (ADS)

Warren, Jeffrey J.; Gray, Harry B.; Winkler, Jay R.; Kozak, John J.

2013-12-01

The geometrical model introduced previously by the authors has been extended quantitatively to document changes in angular correlations between and among residues as azurin unfolds. In the early stages of denaturation, these changes are found to be more pronounced than changes in the spatial displacement of residues, a result that is also found for residues acting in concert, viz., α-helices, β-sheet residues and residues in 'turning regions.' Our analysis leads to a picture of the large-scale motion of the polypeptide chain as azurin denatures. Flanking a central 'ribbon' of residues whose orientation remains essentially invariant, we find that in the early stages of unfolding, left- and right-hand 'wings' adjacent to this stationary scaffolding pivot counterclockwise, while smaller regions on opposing ends of the β-barrel pivot clockwise. As spatial constraints characterising the native state are further relaxed, our calculations show that some regions reverse their orientational motion, reflecting the enhanced flexibility of the polypeptide chain in the denatured state.

Angular correlations in the prompt neutron emission in spontaneous fission of 252Cf

NASA Astrophysics Data System (ADS)

Kopatch, Yuri; Chietera, Andreina; Stuttgé, Louise; Gönnenwein, Friedrich; Mutterer, Manfred; Gagarski, Alexei; Guseva, Irina; Dorvaux, Olivier; Hanappe, Francis; Hambsch, Franz-Josef

2017-09-01

An experiment aiming at the detailed investigation of angular correlations in the neutron emission from spontaneous fission of 252Cf has been performed at IPHC Strasbourg using the angle-sensitive double ionization chamber CODIS for measuring fission fragments and a set of 60 DEMON scintillator counters for neutron detection. The main aim of the experiment is to search for an anisotropy of neutron emission in the center-of-mass system of the fragments. The present status of the data analysis and the full Monte-Carlo simulation of the experiment are reported in the present paper.

Angular-domain scattering interferometry.

PubMed

Shipp, Dustin W; Qian, Ruobing; Berger, Andrew J

2013-11-15

We present an angular-scattering optical method that is capable of measuring the mean size of scatterers in static ensembles within a field of view less than 20 μm in diameter. Using interferometry, the method overcomes the inability of intensity-based models to tolerate the large speckle grains associated with such small illumination areas. By first estimating each scatterer's location, the method can model between-scatterer interference as well as traditional single-particle Mie scattering. Direct angular-domain measurements provide finer angular resolution than digitally transformed image-plane recordings. This increases sensitivity to size-dependent scattering features, enabling more robust size estimates. The sensitivity of these angular-scattering measurements to various sizes of polystyrene beads is demonstrated. Interferometry also allows recovery of the full complex scattered field, including a size-dependent phase profile in the angular-scattering pattern.

Professional tennis players' serve: correlation between segmental angular momentums and ball velocity.

PubMed

Martin, Caroline; Kulpa, Richard; Delamarche, Paul; Bideau, Benoit

2013-03-01

The purpose of the study was to identify the relationships between segmental angular momentum and ball velocity between the following events: ball toss, maximal elbow flexion (MEF), racket lowest point (RLP), maximal shoulder external rotation (MER), and ball impact (BI). Ten tennis players performed serves recorded with a real-time motion capture. Mean angular momentums of the trunk, upper arm, forearm, and the hand-racket were calculated. The anteroposterior axis angular momentum of the trunk was significantly related with ball velocity during the MEF-RLP, RLP-MER, and MER-BI phases. The strongest relationships between the transverse-axis angular momentums and ball velocity followed a proximal-to-distal timing sequence that allows the transfer of angular momentum from the trunk (MEF-RLP and RLP-MER phases) to the upper arm (RLP-MER phase), forearm (RLP-MER and MER-BI phases), and the hand-racket (MER-BI phase). Since sequence is crucial for ball velocity, players should increase angular momentums of the trunk during MEF-MER, upper arm during RLP-MER, forearm during RLP-BI, and the hand-racket during MER-BI.

Measurement of $$B\\bar{B}$$ Angular Correlations based on Secondary Vertex Reconstruction at $$\\sqrt{s}=7$$ TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khachatryan, Vardan; et al.

2011-03-01

A measurement of the angular correlations between beauty and anti-beauty hadrons (B B-bar) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the first time the region of small angular separation. The B hadrons are identified by the presence of displaced secondary vertices from their decays. The B hadron angular separation is reconstructed from the decay vertices and the primary-interaction vertex. The differential B B-bar production cross section, measured from a data sample collected by CMS and corresponding to an integrated luminosity of 3.1 inverse picobarns, shows that a sizablemore » fraction of the B B-bar pairs are produced with small opening angles. These studies provide a test of QCD and further insight into the dynamics of b b-bar production.« less

A new open-loop fiber optic gyro error compensation method based on angular velocity error modeling.

PubMed

Zhang, Yanshun; Guo, Yajing; Li, Chunyu; Wang, Yixin; Wang, Zhanqing

2015-02-27

With the open-loop fiber optic gyro (OFOG) model, output voltage and angular velocity can effectively compensate OFOG errors. However, the model cannot reflect the characteristics of OFOG errors well when it comes to pretty large dynamic angular velocities. This paper puts forward a modeling scheme with OFOG output voltage u and temperature T as the input variables and angular velocity error Δω as the output variable. Firstly, the angular velocity error Δω is extracted from OFOG output signals, and then the output voltage u, temperature T and angular velocity error Δω are used as the learning samples to train a Radial-Basis-Function (RBF) neural network model. Then the nonlinear mapping model over T, u and Δω is established and thus Δω can be calculated automatically to compensate OFOG errors according to T and u. The results of the experiments show that the established model can be used to compensate the nonlinear OFOG errors. The maximum, the minimum and the mean square error of OFOG angular velocity are decreased by 97.0%, 97.1% and 96.5% relative to their initial values, respectively. Compared with the direct modeling of gyro angular velocity, which we researched before, the experimental results of the compensating method proposed in this paper are further reduced by 1.6%, 1.4% and 1.42%, respectively, so the performance of this method is better than that of the direct modeling for gyro angular velocity.

A New Open-Loop Fiber Optic Gyro Error Compensation Method Based on Angular Velocity Error Modeling

PubMed Central

Zhang, Yanshun; Guo, Yajing; Li, Chunyu; Wang, Yixin; Wang, Zhanqing

2015-01-01

With the open-loop fiber optic gyro (OFOG) model, output voltage and angular velocity can effectively compensate OFOG errors. However, the model cannot reflect the characteristics of OFOG errors well when it comes to pretty large dynamic angular velocities. This paper puts forward a modeling scheme with OFOG output voltage u and temperature T as the input variables and angular velocity error Δω as the output variable. Firstly, the angular velocity error Δω is extracted from OFOG output signals, and then the output voltage u, temperature T and angular velocity error Δω are used as the learning samples to train a Radial-Basis-Function (RBF) neural network model. Then the nonlinear mapping model over T, u and Δω is established and thus Δω can be calculated automatically to compensate OFOG errors according to T and u. The results of the experiments show that the established model can be used to compensate the nonlinear OFOG errors. The maximum, the minimum and the mean square error of OFOG angular velocity are decreased by 97.0%, 97.1% and 96.5% relative to their initial values, respectively. Compared with the direct modeling of gyro angular velocity, which we researched before, the experimental results of the compensating method proposed in this paper are further reduced by 1.6%, 1.4% and 1.2%, respectively, so the performance of this method is better than that of the direct modeling for gyro angular velocity. PMID:25734642

On Angular Momentum

DOE R&D Accomplishments Database

Schwinger, J.

1952-01-26

The commutation relations of an arbitrary angular momentum vector can be reduced to those of the harmonic oscillator. This provides a powerful method for constructing and developing the properties of angular momentum eigenvectors. In this paper many known theorems are derived in this way, and some new results obtained. Among the topics treated are the properties of the rotation matrices; the addition of two, three, and four angular momenta; and the theory of tensor operators.

Angular correlation between IceCube high-energy starting events and starburst sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moharana, Reetanjali; Razzaque, Soebur, E-mail: moharana.reetanjali@mail.huji.ac.il, E-mail: srazzaque@uj.ac.za

Starburst galaxies and star-forming regions in the Milkyway, with high rate of supernova activities, are candidate sources of high-energy neutrinos. Using a gamma-ray selected sample of these sources we perform statistical analysis of their angular correlation with the four-year sample of high-energy starting events (HESE), detected by the IceCube Neutrino Observatory. We find that the two samples (starburst galaxies and local star-forming regions) are correlated with cosmic neutrinos at ∼ (2–3)σ (pre-trial) significance level, when the full HESE sample with deposited energy ∼> 20 TeV is considered. However when we consider the HESE sample with deposited energy ∼> 60 TeV,more » which is almost free of atmospheric neutrino and muon backgrounds, the significance of correlation decreased drastically. We perform a similar study for Galactic sources in the 2nd Catalog of Hard Fermi -LAT Sources (2FHL, >50 GeV) catalog as well, obtaining ∼ (2–3)σ (pre-trial) correlation, however the significance of correlation increases with higher cutoff energy in the HESE sample for this case. We also fit available gamma-ray data from these sources using a pp interaction model and calculate expected neutrino fluxes. We find that the expected neutrino fluxes for most of the sources are at least an order of magnitude lower than the fluxes required to produce the HESE neutrinos from these sources. This puts the starburst sources being the origin of the IceCube HESE neutrinos in question.« less

On the correlation of angular position with time of occurrence of gamma-ray bursts

NASA Technical Reports Server (NTRS)

Petrosian, Vahe; Efron, Bradley

1995-01-01

Evidence indicating that a large fraction of gamma-ray bursts are repeaters would provide strong support for noncosmological origin of these sources. Wang & Lingenfelter have claimed existance of a correlation between angular position and time of occurrence of bursts. We perform statistical tests and find a marginal evidence for nearby bursts occurring within 4 to 5 days of each other in the BATSE 1B catalog. This evidence is present also in the 2B catalogs, which in addition, shows some marginal evidence for bursts repetition at longer time delays up to the total length of the observations.

BAO from Angular Clustering: Optimization and Mitigation of Theoretical Systematics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crocce, M.; et al.

We study the theoretical systematics and optimize the methodology in Baryon Acoustic Oscillations (BAO) detections using the angular correlation function with tomographic bins. We calibrate and optimize the pipeline for the Dark Energy Survey Year 1 dataset using 1800 mocks. We compare the BAO fitting results obtained with three estimators: the Maximum Likelihood Estimator (MLE), Profile Likelihood, and Markov Chain Monte Carlo. The MLE method yields the least bias in the fit results (bias/spreadmore » $$\\sim 0.02$$) and the error bar derived is the closest to the Gaussian results (1% from 68% Gaussian expectation). When there is mismatch between the template and the data either due to incorrect fiducial cosmology or photo-$z$ error, the MLE again gives the least-biased results. The BAO angular shift that is estimated based on the sound horizon and the angular diameter distance agree with the numerical fit. Various analysis choices are further tested: the number of redshift bins, cross-correlations, and angular binning. We propose two methods to correct the mock covariance when the final sample properties are slightly different from those used to create the mock. We show that the sample changes can be accommodated with the help of the Gaussian covariance matrix or more effectively using the eigenmode expansion of the mock covariance. The eigenmode expansion is significantly less susceptible to statistical fluctuations relative to the direct measurements of the covariance matrix because the number of free parameters is substantially reduced [$p$ parameters versus $p(p+1)/2$ from direct measurement].« less

Online time-differential perturbed angular correlation study with an 19O beam - Residence sites of oxygen atoms in highly oriented pyrolytic graphite

NASA Astrophysics Data System (ADS)

Sato, W.; Ueno, H.; Watanabe, H.; Miyoshi, H.; Yoshimi, A.; Kameda, D.; Ito, T.; Shimada, K.; Kaihara, J.; Suda, S.; Kobayashi, Y.; Shinohara, A.; Ohkubo, Y.; Asahi, K.

2008-01-01

The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe 19F, the β- decay product of 19O (t1/2 = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, ∣Vzz∣ = 2.91(17) × 1022 V m-2, suggests that the incident 19O atoms are stabilized at an interlayer position with point group C3v. Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive 19O beam.

The odontoid process invagination in normal subjects, Chiari malformation and Basilar invagination patients: Pathophysiologic correlations with angular craniometry

PubMed Central

Ferreira, Jânio A.; Botelho, Ricardo V.

2015-01-01

Background: Craniometric studies have shown that both Chiari malformation (CM) and basilar invagination (BI) belong to a spectrum of malformations. A more precise method to differentiate between these types of CVJM is desirable. The Chamberlain's line violation (CLV) is the most common method to identify BI. The authors sought to clarify the real importance of CLV in the spectrum of craniovertebral junction malformations (CVJM) and to identify possible pathophysiological relationships. Methods: We evaluated the CLV in a sample of CVJM, BI, CM patients and a control group of normal subjects and correlated their data with craniocervical angular craniometry. Results: A total of 97 subjects were studied: 32 normal subjects, 41 CM patients, 9 basilar invagination type 1 (BI1) patients, and 15 basilar invagination type 2 (BI2) patients. The mean CLV violation in the groups were: The control group, 0.16 ± 0.45 cm; the CM group, 0.32 ± 0.48 cm; the BI1 group, 1.35 ± 0.5 cm; and the BI2 group, 1.98 ± 0.18 cm. There was strong correlation between CLV and Boogard's angle (R = 0.82, P = 0.000) and the clivus canal angle (R = 0.7, P = 0.000). Conclusions: CM's CLV is discrete and similar to the normal subjects. BI1 and BI2 presented with at least of 0.95 cm CLV and these violations were strongly correlated with a primary cranial angulation (clivus horizontalization) and an acute clivus canal angle (a secondary craniocervical angle). PMID:26229733

Angular correlations of photons from solution diffraction at a free-electron laser encode molecular structure

DOE PAGES

Mendez, Derek; Watkins, Herschel; Qiao, Shenglan; ...

2016-09-26

During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS), which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL) is an excellent tool for CXS experiments. A protocol is outlinedmore » for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA). From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. Finally, it is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules.« less

Angular filter refractometry analysis using simulated annealing [An improved method for characterizing plasma density profiles using angular filter refractometry

DOE PAGES

Angland, P.; Haberberger, D.; Ivancic, S. T.; ...

2017-10-30

Here, a new method of analysis for angular filter refractometry images was developed to characterize laser-produced, long-scale-length plasmas using an annealing algorithm to iterative converge upon a solution. Angular filter refractometry (AFR) is a novel technique used to characterize the density pro files of laser-produced, long-scale-length plasmas. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on a minimization of themore » $$\\chi$$2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in average uncertainty in the density profile of 5-10% in the region of interest.« less

Angular filter refractometry analysis using simulated annealing [An improved method for characterizing plasma density profiles using angular filter refractometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angland, P.; Haberberger, D.; Ivancic, S. T.

Here, a new method of analysis for angular filter refractometry images was developed to characterize laser-produced, long-scale-length plasmas using an annealing algorithm to iterative converge upon a solution. Angular filter refractometry (AFR) is a novel technique used to characterize the density pro files of laser-produced, long-scale-length plasmas. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on a minimization of themore » $$\\chi$$2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in average uncertainty in the density profile of 5-10% in the region of interest.« less

A METHOD TO EXTRACT THE ANGULAR POWER SPECTRUM OF THE EPOCH OF REIONIZATION FROM LOW-FREQUENCY RADIO INTERFEROMETERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng Qian; Wu Xiangping; Gu Junhua

2012-10-10

The redshifted 21 cm signal of neutral hydrogen from the epoch of reionization (EoR) is extremely weak and its first detection is therefore expected to be statistical with first-generation low-frequency radio interferometers. In this Letter, we propose a method to extract the angular power spectrum of the EoR from the visibility correlation coefficients p{sub ij} (u, v), instead of the visibilities V{sub ij} (u, v) measured directly by radio interferometers in conventional algorithm. The visibility correlation coefficients are defined as p{sub ij}(u,v)=V{sub ij}(u,v)/{radical}(|V{sub ii}||V{sub jj}|) by introducing the autocorrelation terms V{sub ii} and V{sub jj} such that the angular powermore » spectrum C{sub l} can be obtained through C{sub l} = T {sup 2}{sub 0}(|p{sub ij} (u, v)|{sup 2}), independently of the primary beams of antennas. This also partially removes the influence of receiver gains in the measurement of C{sub l} because the amplitudes of the gains cancel each other out in the statistical average operation of (|p{sub ij} (u, v)|{sup 2}). We use the average system temperature T{sub 0} as a calibrator of C{sub l}, which is dominated by the Milky Way and extragalactic sources in the frequency range that we are interested in, below 200 MHz. Finally, we demonstrate the feasibility of this novel method using the simulated sky maps as targets and the 21 CentiMeter Array (21CMA) as interferometer.« less

Preliminary determination of Newtonian gravitational constant with angular acceleration feedback method

PubMed Central

Xue, Chao; Quan, Li-Di; Yang, Shan-Qing; Wang, Bing-Peng; Wu, Jun-Fei; Shao, Cheng-Gang; Tu, Liang-Cheng; Milyukov, Vadim; Luo, Jun

2014-01-01

This paper describes the preliminary measurement of the Newtonian gravitational constant G with the angular acceleration feedback method at HUST. The apparatus has been built, and preliminary measurement performed, to test all aspects of the experimental design, particularly the feedback function, which was recently discussed in detail by Quan et al. The experimental results show that the residual twist angle of the torsion pendulum at the signal frequency introduces 0.4 ppm to the value of G. The relative uncertainty of the angular acceleration of the turntable is approximately 100 ppm, which is mainly limited by the stability of the apparatus. Therefore, the experiment has been modified with three features: (i) the height of the apparatus is reduced almost by half, (ii) the aluminium shelves were replaced with shelves made from ultra-low expansion material and (iii) a perfect compensation of the laboratory-fixed gravitational background will be carried out. With these improvements, the angular acceleration is expected to be determined with an uncertainty of better than 10 ppm, and a reliable value of G with 20 ppm or below will be obtained in the near future. PMID:25201996

The validity of an assessment of maximum angular velocity of knee extension (KE) using a gyroscope.

PubMed

Arai, Takeshi; Obuchi, Shuichi; Shiba, Yoshitaka; Omuro, Kazuya; Inaba, Yasuko; Kojima, Motonaga

2012-01-01

Although it is more important to assess the muscular power of the lower extremities than the strength, no simplified method for doing so has been found. The aim of this study was to assess the validity of the assessment of the angular velocity of KE using a gyroscope. Participants included 105 community-dwelling older people (55 women, 50 men, age ± standard deviation (SD) 75±5.3). Pearson correlation coefficients and Spearman rank-correlation coefficients were used to examine the relationships between the angular velocity of KE and functional performance measurements, a self-efficacy scale and health-related quality of life (HRQOL). The data from the gyroscope were significantly correlated with some physical functions such as muscle strength (r=0.304, p<0.01), and walking velocity (r=0.543, p<0.001). In addition, the joint angular velocity was significantly correlated with self-efficacy (r=0.219-0.329, p<0.01-0.05) and HRQOL (r=0.207-0.359, p<0.01-0.05). The absolute value of the correlation coefficient of angular velocity tended to be greater than that of the muscle strength for mobility functions such as walking velocity and the timed-up-and-go (TUG) test. In conclusion, it was found that the assessment of the angular velocity of the knee joint using a gyroscope could be a feasible and meaningful measurement in the geriatrics field. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The odontoid process invagination in normal subjects, Chiari malformation and Basilar invagination patients: Pathophysiologic correlations with angular craniometry.

PubMed

Ferreira, Jânio A; Botelho, Ricardo V

2015-01-01

Craniometric studies have shown that both Chiari malformation (CM) and basilar invagination (BI) belong to a spectrum of malformations. A more precise method to differentiate between these types of CVJM is desirable. The Chamberlain's line violation (CLV) is the most common method to identify BI. The authors sought to clarify the real importance of CLV in the spectrum of craniovertebral junction malformations (CVJM) and to identify possible pathophysiological relationships. We evaluated the CLV in a sample of CVJM, BI, CM patients and a control group of normal subjects and correlated their data with craniocervical angular craniometry. A total of 97 subjects were studied: 32 normal subjects, 41 CM patients, 9 basilar invagination type 1 (BI1) patients, and 15 basilar invagination type 2 (BI2) patients. The mean CLV violation in the groups were: The control group, 0.16 ± 0.45 cm; the CM group, 0.32 ± 0.48 cm; the BI1 group, 1.35 ± 0.5 cm; and the BI2 group, 1.98 ± 0.18 cm. There was strong correlation between CLV and Boogard's angle (R = 0.82, P = 0.000) and the clivus canal angle (R = 0.7, P = 0.000). CM's CLV is discrete and similar to the normal subjects. BI1 and BI2 presented with at least of 0.95 cm CLV and these violations were strongly correlated with a primary cranial angulation (clivus horizontalization) and an acute clivus canal angle (a secondary craniocervical angle).

An Angular Method with Position Control for Block Mesh Squareness Improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, J.; Stillman, D.

We optimize a target function de ned by angular properties with a position control term for a basic stencil with a block-structured mesh, to improve element squareness in 2D and 3D. Comparison with the condition number method shows that besides a similar mesh quality regarding orthogonality can be achieved as the former does, the new method converges faster and provides a more uniform global mesh spacing in our numerical tests.

Correction of eddy current distortions in high angular resolution diffusion imaging.

PubMed

Zhuang, Jiancheng; Lu, Zhong-Lin; Vidal, Christine Bouteiller; Damasio, Hanna

2013-06-01

To correct distortions caused by eddy currents induced by large diffusion gradients during high angular resolution diffusion imaging without any auxiliary reference scans. Image distortion parameters were obtained by image coregistration, performed only between diffusion-weighted images with close diffusion gradient orientations. A linear model that describes distortion parameters (translation, scale, and shear) as a function of diffusion gradient directions was numerically computed to allow individualized distortion correction for every diffusion-weighted image. The assumptions of the algorithm were successfully verified in a series of experiments on phantom and human scans. Application of the proposed algorithm in high angular resolution diffusion images markedly reduced eddy current distortions when compared to results obtained with previously published methods. The method can correct eddy current artifacts in the high angular resolution diffusion images, and it avoids the problematic procedure of cross-correlating images with significantly different contrasts resulting from very different gradient orientations or strengths. Copyright © 2012 Wiley Periodicals, Inc.

Characteristics of angular cross correlations studied by light scattering from two-dimensional microsphere films

NASA Astrophysics Data System (ADS)

Schroer, M. A.; Gutt, C.; Grübel, G.

2014-07-01

Recently the analysis of scattering patterns by angular cross-correlation analysis (CCA) was introduced to reveal the orientational order in disordered samples with special focus to future applications on x-ray free-electron laser facilities. We apply this CCA approach to ultra-small-angle light-scattering data obtained from two-dimensional monolayers of microspheres. The films were studied in addition by optical microscopy. This combined approach allows to calculate the cross-correlations of the scattering patterns, characterized by the orientational correlation function Ψl(q), as well as to obtain the real-space structure of the monolayers. We show that CCA is sensitive to the orientational order of monolayers formed by the microspheres which are not directly visible from the scattering patterns. By mixing microspheres of different radii the sizes of ordered monolayer domains is reduced. For these samples it is shown that Ψl(q) quantitatively describes the degree of hexagonal order of the two-dimensional films. The experimental CCA results are compared with calculations based on the microscopy images. Both techniques show qualitatively similar features. Differences can be attributed to the wave-front distortion of the laser beam in the experiment. This effect is discussed by investigating the effect of different wave fronts on the cross-correlation analysis results. The so-determined characteristics of the cross-correlation analysis will be also relevant for future x-ray-based studies.

Preliminary determination of Newtonian gravitational constant with angular acceleration feedback method.

PubMed

Xue, Chao; Quan, Li-Di; Yang, Shan-Qing; Wang, Bing-Peng; Wu, Jun-Fei; Shao, Cheng-Gang; Tu, Liang-Cheng; Milyukov, Vadim; Luo, Jun

2014-10-13

This paper describes the preliminary measurement of the Newtonian gravitational constant G with the angular acceleration feedback method at HUST. The apparatus has been built, and preliminary measurement performed, to test all aspects of the experimental design, particularly the feedback function, which was recently discussed in detail by Quan et al. The experimental results show that the residual twist angle of the torsion pendulum at the signal frequency introduces 0.4 ppm to the value of G. The relative uncertainty of the angular acceleration of the turntable is approximately 100 ppm, which is mainly limited by the stability of the apparatus. Therefore, the experiment has been modified with three features: (i) the height of the apparatus is reduced almost by half, (ii) the aluminium shelves were replaced with shelves made from ultra-low expansion material and (iii) a perfect compensation of the laboratory-fixed gravitational background will be carried out. With these improvements, the angular acceleration is expected to be determined with an uncertainty of better than 10 ppm, and a reliable value of G with 20 ppm or below will be obtained in the near future. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Neural correlates for angular head velocity in the rat dorsal tegmental nucleus

NASA Technical Reports Server (NTRS)

Bassett, J. P.; Taube, J. S.; Oman, C. M. (Principal Investigator)

2001-01-01

Many neurons in the rat lateral mammillary nuclei (LMN) fire selectively in relation to the animal's head direction (HD) in the horizontal plane independent of the rat's location or behavior. One hypothesis of how this representation is generated and updated is via subcortical projections from the dorsal tegmental nucleus (DTN). Here we report the type of activity in DTN neurons. The majority of cells (75%) fired as a function of the rat's angular head velocity (AHV). Cells exhibited one of two types of firing patterns: (1) symmetric, in which the firing rate was positively correlated with AHV during head turns in both directions, and (2) asymmetric, in which the firing rate was positively correlated with head turns in one direction and correlated either negatively or not at all in the opposite direction. In addition to modulation by AHV, some of the AHV cells (40.1%) were weakly modulated by the rat's linear velocity, and a smaller number were modulated by HD (11%) or head pitch (15.9%). Autocorrelation analyses indicated that with the head stationary, AHV cells displayed irregular discharge patterns. Because afferents from the DTN are the major source of information projecting to the LMN, these results suggest that AHV information from the DTN plays a significant role in generating the HD signal in LMN. A model is proposed showing how DTN AHV cells can generate and update the LMN HD cell signal.

Mode-sum regularization of ⟨ϕ2⟩ in the angular-splitting method

NASA Astrophysics Data System (ADS)

Levi, Adam; Ori, Amos

2016-08-01

The computation of the renormalized stress-energy tensor or ⟨ϕ2⟩ren in curved spacetime is a challenging task, at both the conceptual and technical levels. Recently we developed a new approach to compute such renormalized quantities in asymptotically flat curved spacetimes, based on the point-splitting procedure. Our approach requires the spacetime to admit some symmetry. We already implemented this approach to compute ⟨ϕ2⟩ren in a stationary spacetime using t splitting, namely splitting in the time-translation direction. Here we present the angular-splitting version of this approach, aimed for computing renormalized quantities in a general (possibly dynamical) spherically symmetric spacetime. To illustrate how the angular-splitting method works, we use it here to compute ⟨ϕ2⟩ren for a quantum massless scalar field in Schwarzschild background, in various quantum states (Boulware, Unruh, and Hartle-Hawking states). We find excellent agreement with the results obtained from the t -splitting variant and also with other methods. Our main goal in pursuing this new mode-sum approach was to enable the computation of the renormalized stress-energy tensor in a dynamical spherically symmetric background, e.g. an evaporating black hole. The angular-splitting variant presented here is most suitable to this purpose.

Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV.

PubMed

Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Guo, L; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E-J; Kim, Y-J; Kim, Y K; Kinney, E; Kiss, Á; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J-C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; Yoo, J S; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S

2015-05-15

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.

Study of the Disintegration Process and of the Angular Moments of the Excited Levels of Pm-147 Using Spectrographic and Angular Correlation Measurements (thesis); ETUDE DU SCHEMA DE DESINTEGRATION ET DES MOMENTS ANGULAIRES DES NIVEAUX EXCITES DU Pm 147 PAR DES MESURES DE SPECTROGRAPHIE ET DE CORRELATIONS ANGULAIRES (these)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philis, C.

1963-07-01

The energies and relative intensities of fifteen gamma lines were determined by a direct spectrographic study. A previously unreported level at 77 plus or minus 2 kev was identified. A coincidence study confirmed the positions of the excited levels of Pm/sup 147/. The 77-kev line was laced between the 409 and 490-kev levels. Angular correlation measurements permitted the assignment of angular moments of 5/2, 7/2, and 5/2 to the 92, 409, and 532-kev levels and of 5/2 or 7/2 to the 685-kev level. The associated mixing coefficients were also obtained. (D.C.W.)

Multiverse effects on the CMB angular correlation function in the framework of NCG

NASA Astrophysics Data System (ADS)

Arabzadeh, Sahar; Kaviani, Kamran

Following many theories that predict the existence of the multiverse and by conjecture that our space-time may have a generalized geometrical structure at the fundamental level, we are interested in using a non-commutative geometry (NCG) formalism to study a suggested two-layer space that contains our 4-dimensional (4D) universe and a re-derived photon propagator. It can be shown that the photon propagator and a cosmic microwave background (CMB) angular correlation function are comparable, and if there exists such a multiverse system, the distance between the two layers can be estimated to be within the observable universe’s radius. Furthermore, this study revealed that our results are not limited to CMB but can be applied to many other types of radiation, such as X-rays.

Image quality in thoracic 4D cone-beam CT: A sensitivity analysis of respiratory signal, binning method, reconstruction algorithm, and projection angular spacing

PubMed Central

Shieh, Chun-Chien; Kipritidis, John; O’Brien, Ricky T.; Kuncic, Zdenka; Keall, Paul J.

2014-01-01

values were found to increase with decreasing RMSE values of projection angular gaps with strong correlations (r ≈ −0.7) regardless of the reconstruction algorithm used. Conclusions: Based on the authors’ results, displacement-based binning methods, better reconstruction algorithms, and the acquisition of even projection angular views are the most important factors to consider for improving thoracic 4D-CBCT image quality. In view of the practical issues with displacement-based binning and the fact that projection angular spacing is not currently directly controllable, development of better reconstruction algorithms represents the most effective strategy for improving image quality in thoracic 4D-CBCT for IGRT applications at the current stage. PMID:24694143

Image quality in thoracic 4D cone-beam CT: A sensitivity analysis of respiratory signal, binning method, reconstruction algorithm, and projection angular spacing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shieh, Chun-Chien; Kipritidis, John; O’Brien, Ricky T.

, SNR values were found to increase with decreasing RMSE values of projection angular gaps with strong correlations (r ≈ −0.7) regardless of the reconstruction algorithm used. Conclusions: Based on the authors’ results, displacement-based binning methods, better reconstruction algorithms, and the acquisition of even projection angular views are the most important factors to consider for improving thoracic 4D-CBCT image quality. In view of the practical issues with displacement-based binning and the fact that projection angular spacing is not currently directly controllable, development of better reconstruction algorithms represents the most effective strategy for improving image quality in thoracic 4D-CBCT for IGRT applications at the current stage.« less

Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d +Au Collisions at √{sN N }=200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Al-Bataineh, H.; Al-Ta'Ani, H.; Alexander, J.; Andrews, K. R.; Angerami, A.; Aoki, K.; Apadula, N.; Appelt, E.; Aramaki, Y.; Armendariz, R.; Aschenauer, E. C.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Belikov, S.; Belmont, R.; Ben-Benjamin, J.; Bennett, R.; Bhom, J. H.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Broxmeyer, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Campbell, S.; Caringi, A.; Castera, P.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Conesa Del Valle, Z.; Connors, M.; Csanád, M.; Csörgő, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; David, G.; Dayananda, M. K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Dutta, D.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Gal, C.; Garishvili, I.; Glenn, A.; Gong, H.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gunji, T.; Guo, L.; Gustafsson, H.-Å.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Hanks, J.; Harper, C.; Hashimoto, K.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hohlmann, M.; Hollis, R. S.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hori, Y.; Hornback, D.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ishihara, M.; Issah, M.; Ivanischev, D.; Iwanaga, Y.; Jacak, B. V.; Jia, J.; Jiang, X.; Jin, J.; John, D.; Johnson, B. M.; Jones, T.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kamin, J.; Kaneti, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Khanzadeev, A.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, D. J.; Kim, E.-J.; Kim, Y.-J.; Kim, Y. K.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kleinjan, D.; Kline, P.; Kochenda, L.; Komkov, B.; Konno, M.; Koster, J.; Kotov, D.; Král, A.; Kravitz, A.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Li, X.; Lichtenwalner, P.; Liebing, P.; Lim, S. H.; Linden Levy, L. A.; Liška, T.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malik, M. D.; Manion, A.; Manko, V. I.; Mannel, E.; Mao, Y.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Means, N.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miki, K.; Milov, A.; Mitchell, J. T.; Miyachi, Y.; Mohanty, A. K.; Moon, H. J.; Morino, Y.; Morreale, A.; Morrison, D. P.; Motschwiller, S.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Newby, J.; Nguyen, M.; Nihashi, M.; Nouicer, R.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Oka, M.; Okada, K.; Onuki, Y.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, B. H.; Park, I. H.; Park, S. K.; Park, W. J.; Pate, S. F.; Patel, L.; Pei, H.; Peng, J.-C.; Pereira, H.; Peressounko, D. Yu.; Petti, R.; Pinkenburg, C.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reygers, K.; Riabov, V.; Riabov, Y.; Richardson, E.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Ružička, P.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakashita, K.; Samsonov, V.; Sano, S.; Sarsour, M.; Sato, T.; Savastio, M.; Sawada, S.; Sedgwick, K.; Seele, J.; Seidl, R.; Seto, R.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shim, H. H.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Sodre, T.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stenlund, E.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Themann, H.; Thomas, D.; Thomas, T. L.; Togawa, M.; Toia, A.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Utsunomiya, K.; Vale, C.; Valle, H.; van Hecke, H. W.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vossen, A.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; Wessels, J.; White, S. N.; Winter, D.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. S.; You, Z.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Phenix Collaboration

2015-05-01

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d +Au and minimum bias p +p collisions at √{sN N }=200 GeV . The charged hadron is measured at midrapidity |η |<0.35 , and the energy is measured at large rapidity (-3.7 <η <-3.1 , Au-going direction). An enhanced near-side angular correlation across |Δ η |>2.75 is observed in d +Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v2 for inclusive charged hadrons at midrapidity up to pT=4.5 GeV /c . We also present the measurement of v2 for identified π± and (anti)protons in central d +Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p +Pb at √{sN N }=5.02 TeV . The magnitude of the mass ordering in d +Au is found to be smaller than that in p +Pb collisions, which may indicate smaller radial flow in lower energy d +Au collisions.

Herschel-ATLAS: The Angular Correlation Function of Submillimetre Galaxies at High and Low Redshift

NASA Technical Reports Server (NTRS)

Maddox, S. J.; Dunne, L.; Rigby, E.; Eales, S.; Cooray, A.; Scott, D.; Peacock, J. A.; Negrello, M.; Smith, D. J. B.; Benford, D.;

Joint image reconstruction method with correlative multi-channel prior for x-ray spectral computed tomography

NASA Astrophysics Data System (ADS)

Kazantsev, Daniil; Jørgensen, Jakob S.; Andersen, Martin S.; Lionheart, William R. B.; Lee, Peter D.; Withers, Philip J.

2018-06-01

Rapid developments in photon-counting and energy-discriminating detectors have the potential to provide an additional spectral dimension to conventional x-ray grayscale imaging. Reconstructed spectroscopic tomographic data can be used to distinguish individual materials by characteristic absorption peaks. The acquired energy-binned data, however, suffer from low signal-to-noise ratio, acquisition artifacts, and frequently angular undersampled conditions. New regularized iterative reconstruction methods have the potential to produce higher quality images and since energy channels are mutually correlated it can be advantageous to exploit this additional knowledge. In this paper, we propose a novel method which jointly reconstructs all energy channels while imposing a strong structural correlation. The core of the proposed algorithm is to employ a variational framework of parallel level sets to encourage joint smoothing directions. In particular, the method selects reference channels from which to propagate structure in an adaptive and stochastic way while preferring channels with a high data signal-to-noise ratio. The method is compared with current state-of-the-art multi-channel reconstruction techniques including channel-wise total variation and correlative total nuclear variation regularization. Realistic simulation experiments demonstrate the performance improvements achievable by using correlative regularization methods.

Influence of tungsten fiber's slow drift on the measurement of G with angular acceleration method.

PubMed

Luo, Jie; Wu, Wei-Huang; Xue, Chao; Shao, Cheng-Gang; Zhan, Wen-Ze; Wu, Jun-Fei; Milyukov, Vadim

2016-08-01

In the measurement of the gravitational constant G with angular acceleration method, the equilibrium position of torsion pendulum with tungsten fiber undergoes a linear slow drift, which results in a quadratic slow drift on the angular velocity of the torsion balance turntable under feedback control unit. The accurate amplitude determination of the useful angular acceleration signal with known frequency is biased by the linear slow drift and the coupling effect of the drifting equilibrium position and the room fixed gravitational background signal. We calculate the influences of the linear slow drift and the complex coupling effect on the value of G, respectively. The result shows that the bias of the linear slow drift on G is 7 ppm, and the influence of the coupling effect is less than 1 ppm.

Influence of tungsten fiber's slow drift on the measurement of G with angular acceleration method

NASA Astrophysics Data System (ADS)

Luo, Jie; Wu, Wei-Huang; Xue, Chao; Shao, Cheng-Gang; Zhan, Wen-Ze; Wu, Jun-Fei; Milyukov, Vadim

2016-08-01

In the measurement of the gravitational constant G with angular acceleration method, the equilibrium position of torsion pendulum with tungsten fiber undergoes a linear slow drift, which results in a quadratic slow drift on the angular velocity of the torsion balance turntable under feedback control unit. The accurate amplitude determination of the useful angular acceleration signal with known frequency is biased by the linear slow drift and the coupling effect of the drifting equilibrium position and the room fixed gravitational background signal. We calculate the influences of the linear slow drift and the complex coupling effect on the value of G, respectively. The result shows that the bias of the linear slow drift on G is 7 ppm, and the influence of the coupling effect is less than 1 ppm.

Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing

NASA Astrophysics Data System (ADS)

Tugendhat, Tim M.; Schäfer, Björn Malte

2018-05-01

We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak-lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between ℓ ≃ 40 and ℓ ≃ 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.

The feasibility of measuring joint angular velocity with a gyro-sensor.

PubMed

Arai, Takeshi; Obuchi, Shuichi; Shiba, Yoshitaka; Omuro, Kazuya; Nakano, Chika; Higashi, Takuya

2008-01-01

To determine the reliability of an assessment of joint angular velocity using a gyro-sensor and to examine the relationship between ankle angular velocity and physical functions. Cross-sectional. Kinesiology laboratory. Twenty healthy young adults (mean age, 22.5 y) and 113 community-dwelling older adults (mean age, 75.1 y). Not applicable. Maximal ankle joint velocity was measured using a gyro-sensor during heel-rising and jumping with knee extended. The intraclass correlation coefficient (ICC) was used to determine the intertester and intratester reliability. The Pearson correlation coefficient was used to examine the relationships between maximal ankle joint velocity and isometric muscle strength and isokinetic muscle power in young adults and also to examine the relationships between maximal ankle joint velocity and functional performance measurements such as walking time in older adults. High reliability was found for intertester (ICC=.96) and intratester reliability (ICC=.96). The data from the gyro-sensor highly correlated with muscle strength (r range, .62-.68; P<.01) and muscle power (r range, .45-.79; P range, .01-.05). In older subjects, mobility functions significantly correlated with the angular velocity of ankle plantarflexion. Measurement of ankle angular velocity using a gyro-sensor is both reliable and feasible, with the results representing a significant correlation to muscle power and performance measurements.

Smoothed dissipative particle dynamics with angular momentum conservation

NASA Astrophysics Data System (ADS)

Müller, Kathrin; Fedosov, Dmitry A.; Gompper, Gerhard

2015-01-01

Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier-Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor-Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.

Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central d + Au collisions at s N N = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adare, A.; Aidala, C.; Ajitanand, N. N.

2015-05-12

In this study, we present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and aluminum bias p+p collisions at √s NN = 200 GeV. The charged hadron is measured at midrapidity lηl < 0.35, and the energy us measured at large rapidity (–3.7 < η < –3.1, Au-going direction). An enhanced near-side angular correlation across lΔηl > 2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v₂ for inclusive charged hadrons at midrapidity up to p T = 4.5 GeV/c.more » We also present the measurement of v₂ for identified π ± and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at √s NN = 5.02 TeV. The magnitude of the mass-ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.« less

Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shanzhi, E-mail: shanzhit@gmail.com; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049; Wang, Zhao

The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely whenmore » the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002{sup ″}. Experiment has proved its feasibility and practicability.« less

Influence of tungsten fiber’s slow drift on the measurement of G with angular acceleration method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Jie; Wu, Wei-Huang; Zhan, Wen-Ze

In the measurement of the gravitational constant G with angular acceleration method, the equilibrium position of torsion pendulum with tungsten fiber undergoes a linear slow drift, which results in a quadratic slow drift on the angular velocity of the torsion balance turntable under feedback control unit. The accurate amplitude determination of the useful angular acceleration signal with known frequency is biased by the linear slow drift and the coupling effect of the drifting equilibrium position and the room fixed gravitational background signal. We calculate the influences of the linear slow drift and the complex coupling effect on the value ofmore » G, respectively. The result shows that the bias of the linear slow drift on G is 7 ppm, and the influence of the coupling effect is less than 1 ppm.« less

Angular-Rate Estimation Using Quaternion Measurements

NASA Technical Reports Server (NTRS)

Azor, Ruth; Bar-Itzhack, Y.; Deutschmann, Julie K.; Harman, Richard R.

1998-01-01

In most spacecraft (SC) there is a need to know the SC angular rate. Precise angular rate is required for attitude determination, and a coarse rate is needed for attitude control damping. Classically, angular rate information is obtained from gyro measurements. These days, there is a tendency to build smaller, lighter and cheaper SC, therefore the inclination now is to do away with gyros and use other means and methods to determine the angular rate. The latter is also needed even in gyro equipped satellites when performing high rate maneuvers whose angular-rate is out of range of the on board gyros or in case of gyro failure. There are several ways to obtain the angular rate in a gyro-less SC. When the attitude is known, one can differentiate the attitude in whatever parameters it is given and use the kinematics equation that connects the derivative of the attitude with the satellite angular-rate and compute the latter. Since SC usually utilize vector measurements for attitude determination, the differentiation of the attitude introduces a considerable noise component in the computed angular-rate vector.

Characterization of thigh and shank segment angular velocity during jump landing tasks commonly used to evaluate risk for ACL injury.

PubMed

Dowling, Ariel V; Favre, Julien; Andriacchi, Thomas P

2012-09-01

The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28-0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms.

Stern-Gerlach-like approach to electron orbital angular momentum measurement

DOE PAGES

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

2017-02-28

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less

Stern-Gerlach-like approach to electron orbital angular momentum measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less

Measurement of long-range near-side two-particle angular correlations in pp collisions at $$\\sqrt{s}$$ = 13 TeV

DOE PAGES

Khachatryan, Vardan

2016-04-27

Our results on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270 nb -1. The correlations are studied over a broad range of pseudorapidity (|η| < 2.4) and over the full azimuth (Φ) as a function of charged particle multiplicity and transverse momentum (p T). In high-multiplicity events, a long-range (|Δη| > 2.0), near-side (ΔΦ≈ 0) structure emerges in the two-particle Dh–Df correlation functions. The magnitude of the correlation exhibitsmore » a pronounced maximum in the range 1.0 < p T < 2.0 GeV/c and an approximately linear increase with the charged particle multiplicity. The overall correlation strength at √s = 13 TeV is similar to that found in earlier pp data at √s = 7 TeV, but is measured up to much higher multiplicity values. We observed long-range correlations are compared to those seen in pp, pPb, and PbPb collisions at lower collision energies.« less

Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at √{s}=7 TeV

NASA Astrophysics Data System (ADS)

Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Anwar, R.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barioglio, L.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Boldizsár, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buhler, P.; Buitron, S. A. I.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Caines, H.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Capon, A. A.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; del Valle, Z. Conesa; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovská, J.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Degenhardt, H. F.; Deisting, A.; Deloff, A.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Corchero, M. A. Diaz; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Duggal, A. K.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erhardt, F.; Espagnon, B.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Girard, M. Fusco; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Garg, P.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Ducati, M. B. Gay; Germain, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Graham, K. L.; Greiner, L.; Grelli, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grion, N.; Gronefeld, J. M.; Grosa, F.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Grull, F. R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Hladky, J.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Ippolitov, M.; Irfan, M.; Isakov, V.; Islam, M. S.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jercic, M.; Bustamante, R. T. Jimenez; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Uysal, A. Karasu; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Khuntia, A.; Kielbowicz, M. M.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Meethaleveedu, G. Koyithatta; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kundu, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lavicka, R.; Lazaridis, L.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lehrbach, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Litichevskyi, V.; Ljunggren, H. M.; Llope, W. J.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Loncar, P.; Lopez, X.; Torres, E. López; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Cervantes, I. Maldonado; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Pedreira, M. Martinez; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Mathis, A. M.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mishra, T.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montes, E.; De Godoy, D. A. Moreira; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Myers, C. J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Nesbo, S. V.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Ohlson, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pacik, V.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Panebianco, S.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, J.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; Pereira, L. G.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Pezzi, R. P.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Pozdniakov, V.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Rana, D. B.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ratza, V.; Ravasenga, I.; Read, K. F.; Redlich, K.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sandoval, A.; Sarkar, D.; Sarkar, N.; Sarma, P.; Sas, M. H. P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M. O.; Schmidt, M.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sett, P.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Suzuki, K.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Muñoz, G. Tejeda; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thakur, D.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Tripathy, S.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Trzeciak, B. A.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Umaka, E. N.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Limón, S. Vergara; Vernet, R.; Vértesi, R.; Vickovic, L.; Vigolo, S.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Voscek, D.; Vranic, D.; Vrláková, J.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Witt, W. E.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zimmermann, S.; Zinovjev, G.; Zmeskal, J.

2017-08-01

Two-particle angular correlations were measured in pp collisions at √{s} = 7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon-baryon and anti-baryon-anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an open question.

Angular power spectrum in publically released ALICE events

NASA Astrophysics Data System (ADS)

Llanes-Estrada, Felipe J.; Muñoz Martinez, Jose L.

2018-02-01

We study the particles emitted in the fireball following a Relativistic Heavy Ion Collision with the traditional angular analysis employed in cosmology and earth sciences, producing Mollweide plots of the number and pt distribution of a few actual, publically released ALICE-collaboration events and calculating their angular power spectrum. We also examine the angular spectrum of a simple two-particle correlation. While this may not be the optimal way of analyzing heavy ion data, our intention is to provide a one to one comparison to analysis in cosmology. With the limited statistics at hand, we do not find evidence for acoustic peaks but a decrease of Cl that is reminiscent of viscous attenuation, but subject to a strong effect from the rapidity acceptance which probably dominates (so we also subtract the m = 0 component). As an exercise, we still extract a characteristic Silk damping length (proportional to the square root of the viscosity over entropy density ratio) to illustrate the method. The absence of acoustic-like peaks is also compatible with a crossover from the QGP to the hadron gas (because a surface tension at domain boundaries would effect a restoring force that could have driven acoustic oscillations). Presently we do not understand a depression of the l = 6 multipole strength; perhaps ALICE could reexamine it with full statistics.

Gluon correlations from a glasma flux-tube model compared to measured hadron correlations on transverse momentum (p t,p t) and angular differences (η Δ,φ Δ)

DOE PAGES

Trainor, Thomas A.; Ray, R. L.

2011-09-09

A glasma flux-tube model has been proposed to explain strong elongation on pseudorapidity η of the same-side two-dimensional (2D) peak in minimum-bias angular correlations from √( sNN)=200 GeV Au-Au collisions. The same-side peak or “soft ridge” is said to arise from coupling of flux tubes to radial flow whereby gluons radiated transversely from flux tubes are boosted by radial flow to form a narrow structure or ridge on azimuth. In this study we test the theory conjecture by comparing measurements to predictions for particle production, spectra, and correlations from the glasma model and from conventional fragmentation processes. We conclude thatmore » the glasma model is contradicted by measured hadron yields, spectra, and correlations, whereas a two-component model of hadron production, including minimum-bias parton fragmentation, provides a quantitative description of most features of the data, although η elongation of the same-side 2D peak remains undescribed.« less

Correlation between X-ray flux and rotational acceleration in Vela X-1

NASA Technical Reports Server (NTRS)

Deeter, J. E.; Boynton, P. E.; Shibazaki, N.; Hayakawa, S.; Nagase, F.

1989-01-01

The results of a search for correlations between X-ray flux and angular acceleration for the accreting binary pulsar Vela X-1 are presented. Results are based on data obtained with the Hakucho satellite during the interval 1982 to 1984. In undertaking this correlation analysis, it was necessary to modify the usual statistical method to deal with conditions imposed by generally unavoidable satellite observing constraints, most notably a mismatch in sampling between the two variables. The results are suggestive of a correlation between flux and the absolute value of the angular acceleration, at a significance level of 96 percent. The implications of the methods and results for future observations and analysis are discussed.

A novel clinical evaluation method using maximum angular velocity during knee extension to assess lower extremity muscle function of older adults.

PubMed

Arai, Takeshi; Obuchi, Shuichi; Shiba, Yoshitaka

2017-11-01

The purpose of this study is to examine the utilities of maximum angular velocity (AV) assessment during knee extension (KE) using a gyroscope for clinical evaluation of exercise program for older adults. Two hundred and 4 community-dwelling older adults underwent a 3-month exercise intervention program. Outcome measures included AV during KE and other physical functions (isometric strength (IS), walking abilities, and balance functions). A correlation coefficient was used to evaluate the relationships between AV and other physical functions at baseline. The differences of physical functions before and after intervention were evaluated and the effect size of each measurement was calculated after the program. The AV measurement was significantly correlated with IS during KE (r=0.303, P<0.01) and other physical functions. Most correlation coefficients of angular velocity were greater than that of IS. All of physical assessments were significantly improved. Also, effect size of AV was greater than that of IS (d=0.45 vs. 0.42). AV of the lower extremities is useful to evaluate the effects of exercise intervention in the elderly. Copyright © 2017 Elsevier B.V. All rights reserved.

Inclusion of angular momentum in FREYA

DOE PAGES

Randrup, Jørgen; Vogt, Ramona

2015-05-18

The event-by-event fission model FREYA generates large samples of complete fission events from which any observable can extracted, including fluctuations of the observables and the correlations between them. We describe here how FREYA was recently refined to include angular momentum throughout. Subsequently we present some recent results for both neutron and photon observables.

Break-technique handheld dynamometry: relation between angular velocity and strength measurements.

PubMed

Burns, Stephen P; Spanier, David E

2005-07-01

To determine whether the muscle strength, as measured with break-technique handheld dynamometry (HHD), is dependent on the angular velocity achieved during testing and to compare reliability at different angular velocities. Repeated-measures study. Participants underwent HHD by using make-technique (isometric) and break-technique (eccentric) dynamometry at 3 prespecified angular velocities. Elbow movement was recorded with an electrogoniometer. Inpatient spinal cord injury unit. Convenience sample of 20 persons with tetraplegia with weakness of elbow flexors or extensors. Not applicable. Elbow angular velocity and muscle strength recorded during HHD. With the break technique, angular velocities averaging 15 degrees , 33 degrees , and 55 degrees /s produced 16%, 30%, and 51% greater strength measurements, respectively, than velocities recorded by using the make technique (all P < .006 for comparisons between successive techniques). The intraclass correlation coefficient for intrarater reliability was .89 or greater for all testing techniques. Greater strength is recorded with faster angular velocities during HHD. Differences in angular velocity may explain the wide range previously reported for break- versus make-technique strength measurements. Variation in angular velocity is a potential source of variability in serial HHD strength measurements, and for this reason the make technique may be preferable.

Amplification of Angular Rotations Using Weak Measurements

NASA Astrophysics Data System (ADS)

Magaña-Loaiza, Omar S.; Mirhosseini, Mohammad; Rodenburg, Brandon; Boyd, Robert W.

2014-05-01

We present a weak measurement protocol that permits a sensitive estimation of angular rotations based on the concept of weak-value amplification. The shift in the state of a pointer, in both angular position and the conjugate orbital angular momentum bases, is used to estimate angular rotations. This is done by an amplification of both the real and imaginary parts of the weak-value of a polarization operator that has been coupled to the pointer, which is a spatial mode, via a spin-orbit coupling. Our experiment demonstrates the first realization of weak-value amplification in the azimuthal degree of freedom. We have achieved effective amplification factors as large as 100, providing a sensitivity that is on par with more complicated methods that employ quantum states of light or extremely large values of orbital angular momentum.

Induced Angular Momentum

ERIC Educational Resources Information Center

Parker, G. W.

1978-01-01

Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)

Fast two-position initial alignment for SINS using velocity plus angular rate measurements

NASA Astrophysics Data System (ADS)

Chang, Guobin

2015-10-01

An improved two-position initial alignment model for strapdown inertial navigation system is proposed. In addition to the velocity, angular rates are incorporated as measurements. The measurement equations in full three channels are derived in both navigation and body frames and the latter of which is found to be preferred. The cross-correlation between the process and the measurement noises is analyzed and addressed in the Kalman filter. The incorporation of the angular rates, without introducing additional device or external signal, speeds up the convergence of estimating the attitudes, especially the heading. In the simulation study, different algorithms are tested with different initial errors, and the advantages of the proposed method compared to the conventional one are validated by the simulation results.

Natural roller bearing fault detection by angular measurement of true instantaneous angular speed

NASA Astrophysics Data System (ADS)

Renaudin, L.; Bonnardot, F.; Musy, O.; Doray, J. B.; Rémond, D.

2010-10-01

The challenge in many production activities involving large mechanical devices like power transmissions consists in reducing the machine downtime, in managing repairs and in improving operating time. Most online monitoring systems are based on conventional vibration measurement devices for gear transmissions or bearings in mechanical components. In this paper, we propose an alternative way of bearing condition monitoring based on the instantaneous angular speed measurement. By the help of a large experimental investigation on two different applications, we prove that localized faults like pitting in bearing generate small angular speed fluctuations which are measurable with optical or magnetic encoders. We also emphasize the benefits of measuring instantaneous angular speed with the pulse timing method through an implicit angular sampling which ensures insensitivity to speed fluctuation. A wide range of operating conditions have been tested for the two applications with varying speed, load, external excitations, gear ratio, etc. The tests performed on an automotive gearbox or on actual operating vehicle wheels also establish the robustness of the proposed methodology. By the means of a conventional Fourier transform, angular frequency channels kinematically related to the fault periodicity show significant magnitude differences related to the damage severity. Sideband effects are evidently seen when the fault is located on rotating parts of the bearing due to load modulation. Additionally, slip effects are also suspected to be at the origin of enlargement of spectrum peaks in the case of double row bearings loaded in a pure radial direction.

Nuclear scissors modes and hidden angular momenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balbutsev, E. B., E-mail: balbuts@theor.jinr.ru; Molodtsova, I. V.; Schuck, P.

The coupled dynamics of low-lying modes and various giant resonances are studied with the help of the Wigner Function Moments method generalized to take into account spin degrees of freedom and pair correlations simultaneously. The method is based on Time-Dependent Hartree–Fock–Bogoliubov equations. The model of the harmonic oscillator including spin–orbit potential plus quadrupole–quadrupole and spin–spin interactions is considered. New low-lying spin-dependent modes are analyzed. Special attention is paid to the scissors modes. A new source of nuclear magnetism, connected with counter-rotation of spins up and down around the symmetry axis (hidden angular momenta), is discovered. Its inclusion into the theorymore » allows one to improve substantially the agreement with experimental data in the description of energies and transition probabilities of scissors modes.« less

Two-dimensional angular transmission characterization of CPV modules.

PubMed

Herrero, R; Domínguez, C; Askins, S; Antón, I; Sala, G

2010-11-08

This paper proposes a fast method to characterize the two-dimensional angular transmission function of a concentrator photovoltaic (CPV) system. The so-called inverse method, which has been used in the past for the characterization of small optical components, has been adapted to large-area CPV modules. In the inverse method, the receiver cell is forward biased to produce a Lambertian light emission, which reveals the reverse optical path of the optics. Using a large-area collimator mirror, the light beam exiting the optics is projected on a Lambertian screen to create a spatially resolved image of the angular transmission function. An image is then obtained using a CCD camera. To validate this method, the angular transmission functions of a real CPV module have been measured by both direct illumination (flash CPV simulator and sunlight) and the inverse method, and the comparison shows good agreement.

Accuracy of visual estimates of joint angle and angular velocity using criterion movements.

PubMed

Morrison, Craig S; Knudson, Duane; Clayburn, Colby; Haywood, Philip

2005-06-01

A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement.

Vibration signal correction of unbalanced rotor due to angular speed fluctuation

NASA Astrophysics Data System (ADS)

Cao, Hongrui; He, Dong; Xi, Songtao; Chen, Xuefeng

2018-07-01

The rotating speed of a rotor is hardly constant in practice due to angular speed fluctuation, which affects the balancing accuracy of the rotor. In this paper, the effect of angular speed fluctuation on vibration responses of the unbalanced rotor is analyzed quantitatively. Then, a vibration signal correction method based on zoom synchrosqueezing transform (ZST) and tacholess order tracking is proposed. The instantaneous angular speed (IAS) of the rotor is extracted by the ZST firstly and then used to calculate the instantaneous phase. The vibration signal is further resampled in angular domain to reduce the effect of angular speed fluctuation. The signal obtained in angular domain is transformed into order domain using discrete Fourier transform (DFT) to estimate the amplitude and phase of the vibration signal. Simulated and experimental results show that the proposed method can successfully correct the amplitude and phase of the vibration signal due to angular speed fluctuation.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay.

PubMed

Collett, B; Bateman, F; Bauder, W K; Byrne, J; Byron, W A; Chen, W; Darius, G; DeAngelis, C; Dewey, M S; Gentile, T R; Hassan, M T; Jones, G L; Komives, A; Laptev, A; Mendenhall, M P; Nico, J S; Noid, G; Park, H; Stephenson, E J; Stern, I; Stockton, K J S; Trull, C; Wietfeldt, F E; Yerozolimsky, B G

2017-08-01

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

A Universal Angular Momentum Profile for Dark Matter Halos

NASA Astrophysics Data System (ADS)

Liao, Shihong; Chen, Jianxiong; Chu, M.-C.

2017-07-01

The angular momentum distribution in dark matter halos and galaxies is a key ingredient in understanding their formation. Specifically, the internal distribution of angular momenta is closely related to the formation of disk galaxies. In this article, we use halos identified from a high-resolution simulation, the Bolshoi simulation, to study the spatial distribution of specific angular momenta, j(r,θ ). We show that by stacking halos with similar masses to increase the signal-to-noise ratio, the profile can be fitted as a simple function, j{(r,θ )={j}s{\\sin }2{(θ /{θ }s)(r/{r}s)}2/(1+r/{r}s)}4, with three free parameters, {j}s,{r}s, and {θ }s. Specifically, j s correlates with the halo mass M vir as {j}s\\propto {M}{vir}2/3, r s has a weak dependence on the halo mass as {r}s\\propto {M}{vir}0.040, and {θ }s is independent of M vir. This profile agrees with that from a rigid shell model, though its origin is unclear. Our universal specific angular momentum profile j(r,θ ) is useful in modeling the angular momenta of halos. Furthermore, by using an empirical stellar mass-halo mass relation, we can infer the average angular momentum distribution of a dark matter halo. The specific angular momentum-stellar mass relation within a halo computed from our profile is shown to share a similar shape as that from the observed disk galaxies.

Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at $$\\sqrt{\\mathrm{s}}=7$$ TeV

DOE PAGES

Adam, J.; Adamová, D.; Aggarwal, M. M.; ...

2017-08-24

We measured two-particle angular correlations in pp collisions at √s=7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon–baryon and anti-baryon–anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an openmore » question.« less

Development and Validation of a Method for Determining Tridimensional Angular Displacements with Special Applications to Ice Hockey Motions.

ERIC Educational Resources Information Center

Gagnon, Micheline; And Others

1983-01-01

A method for determining the tridimensional angular displacement of skates during the two-legged stop in ice hockey was developed and validated. The angles were measured by geometry, using a cinecamera and specially equipped skates. The method provides a new tool for kinetic analyses of skating movements. (Authors/PP)

Simplified Generation of High-Angular-Momentum Light Beams

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Strekalov, Dmitry; Grudinin, Ivan

2007-01-01

A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum light beams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum light beams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum light beam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the

The three-dimensional angular widths of CMEs and their relations to the source regions

NASA Astrophysics Data System (ADS)

Zhao, X.; Feng, X. S.

2017-12-01

The angular width of a coronal mass ejection (CME) is an important factor to determine whether the corresponding interplanetary CME (ICME) and its preceding shock will reach our Earth. However, very few studies are involved to study the decisive factors of the CME's angular width. In this study, we use the three-dimensional (3D) angular width of CMEs obtained from the Graduated Cylindrical Shell (GCS) model based on observations of Solar Terrestrial Relations Observatory (STEREO) to study the relations between the CME's 3D width and characteristics of the CME's source region. We find that for the CMEs produced by active regions (ARs), the CME width has some correlations with the AR's area and flux, but these correlations are not strong. The magnetic flux contained in the CME seems to come from only part of the AR's total flux. For the CMEs produced by flare regions, the correlations between the CME angular width and the flare region's area and flux are strong. The magnetic flux within those CMEs seems to totally (even not enough) come from the flare region. Our findings prefer to support that the CME's 3D angular width can be generally estimated based on observations of Solar Dynamics Observatory (SDO) for its source region instead of the observations from coronagraphs onboard Solar and Heliospheric Observatory (SOHO) and STEREO.

A dual-heterodyne laser interferometer for simultaneous measurement of linear and angular displacements.

PubMed

Yan, Hao; Duan, Hui-Zong; Li, Lin-Tao; Liang, Yu-Rong; Luo, Jun; Yeh, Hsien-Chi

2015-12-01

Picometer laser interferometry is an essential tool for ultra-precision measurements in frontier scientific research and advanced manufacturing. In this paper, we present a dual-heterodyne laser interferometer for simultaneously measuring linear and angular displacements with resolutions of picometer and nanoradian, respectively. The phase measurement method is based on cross-correlation analysis and realized by a PXI-bus data acquisition system. By implementing a dual-heterodyne interferometer with a highly symmetric optical configuration, low frequency noises caused by the environmental fluctuations can be suppressed to very low levels via common-mode noise rejection. Experimental results for the dual-heterodyne interferometer configuration presented demonstrate that the noise levels of the linear and angular displacement measurements are approximately 1 pm/Hz(1/2) and 0.5 nrad/Hz(1/2) at 1 Hz.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

DOE PAGES

Collett, B.; Bateman, F.; Bauder, W. K.; ...

2017-08-01

Here, we describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. This apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. We present details of the method, apparatus, detectors, data acquisition, and data reduction scheme, along with a discussion of the important systematic effects.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collett, B.; Bateman, F.; Bauder, W. K.

Here, we describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. This apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. We present details of the method, apparatus, detectors, data acquisition, and data reduction scheme, along with a discussion of the important systematic effects.

Measurement of Long-Range Near-Side Two-Particle Angular Correlations in pp Collisions at sqrt[s]=13  TeV.

PubMed

Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Asilar, E; Bergauer, T; Brandstetter, J; Brondolin, E; Dragicevic, M; Erö, J; Flechl, M; Friedl, M; Frühwirth, R; Ghete, V M; Hartl, C; Hörmann, N; Hrubec, J; Jeitler, M; Knünz, V; König, A; Krammer, M; Krätschmer, I; Liko, D; Matsushita, T; Mikulec, I; Rabady, D; Rahbaran, B; Rohringer, H; Schieck, J; Schöfbeck, R; Strauss, J; Treberer-Treberspurg, W; Waltenberger, W; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Alderweireldt, S; Cornelis, T; De Wolf, E A; Janssen, X; Knutsson, A; Lauwers, J; Luyckx, S; Van De Klundert, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Van Spilbeeck, A; Abu Zeid, S; Blekman, F; D'Hondt, J; Daci, N; De Bruyn, I; Deroover, K; Heracleous, N; Keaveney, J; Lowette, S; Moreels, L; Olbrechts, A; Python, Q; Strom, D; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Van Parijs, I; Barria, P; Brun, H; Caillol, C; Clerbaux, B; De Lentdecker, G; Fasanella, G; Favart, L; Grebenyuk, A; Karapostoli, G; Lenzi, T; Léonard, A; Maerschalk, T; Marinov, A; Perniè, L; Randle-Conde, A; Seva, T; Vander Velde, C; Vanlaer, P; Yonamine, R; Zenoni, F; Zhang, F; Beernaert, K; Benucci, L; Cimmino, A; Crucy, S; Dobur, D; Fagot, A; Garcia, G; Gul, M; Mccartin, J; Ocampo Rios, A A; Poyraz, D; Ryckbosch, D; Salva, S; Sigamani, M; Tytgat, M; Van Driessche, W; Yazgan, E; Zaganidis, N; Basegmez, S; Beluffi, C; Bondu, O; Brochet, S; Bruno, G; Caudron, A; Ceard, L; Da Silveira, G G; Delaere, C; Favart, D; Forthomme, L; Giammanco, A; Hollar, J; Jafari, A; Jez, P; Komm, M; Lemaitre, V; Mertens, A; Musich, M; Nuttens, C; Perrini, L; Pin, A; Piotrzkowski, K; Popov, A; Quertenmont, L; Selvaggi, M; Vidal Marono, M; Beliy, N; Hammad, G H; Aldá Júnior, W L; Alves, F L; Alves, G A; Brito, L; Correa Martins Junior, M; Hamer, M; Hensel, C; Moraes, A; Pol, M E; Rebello Teles, P; Belchior Batista Das Chagas, E; Carvalho, W; Chinellato, J; Custódio, A; Da Costa, E M; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Huertas Guativa, L M; Malbouisson, H; Matos Figueiredo, D; Mora Herrera, C; Mundim, L; Nogima, H; Prado Da Silva, W L; Santoro, A; Sznajder, A; Tonelli Manganote, E J; Vilela Pereira, A; Ahuja, S; Bernardes, C A; De Souza Santos, A; Dogra, S; Tomei, T R Fernandez Perez; Gregores, E M; Mercadante, P G; Moon, C S; Novaes, S F; Padula, Sandra S; Romero Abad, D; Ruiz Vargas, J C; Aleksandrov, A; Hadjiiska, R; Iaydjiev, P; Rodozov, M; Stoykova, S; Sultanov, G; Vutova, M; Dimitrov, A; Glushkov, I; Litov, L; Pavlov, B; Petkov, P; Ahmad, M; Bian, J G; Chen, G M; Chen, H S; Chen, M; Cheng, T; Du, R; Jiang, C H; Plestina, R; Romeo, F; Shaheen, S M; Spiezia, A; Tao, J; Wang, C; Wang, Z; Zhang, H; Asawatangtrakuldee, C; Ban, Y; Li, Q; Liu, S; Mao, Y; Qian, S J; Wang, D; Xu, Z; Avila, C; Cabrera, A; Chaparro Sierra, L F; Florez, C; Gomez, J P; Gomez Moreno, B; Sanabria, J C; Godinovic, N; Lelas, D; Puljak, I; Ribeiro Cipriano, P M; Antunovic, Z; Kovac, M; Brigljevic, V; Kadija, K; Luetic, J; Micanovic, S; Sudic, L; Attikis, A; Mavromanolakis, G; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Rykaczewski, H; Bodlak, M; Finger, M; Finger, M; El-Khateeb, E; Elkafrawy, T; Mohamed, A; Salama, E; Calpas, B; Kadastik, M; Murumaa, M; Raidal, M; Tiko, A; Veelken, C; Eerola, P; Pekkanen, J; Voutilainen, M; Härkönen, J; Karimäki, V; Kinnunen, R; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Peltola, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Wendland, L; Talvitie, J; Tuuva, T; Besancon, M; Couderc, F; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Favaro, C; Ferri, F; Ganjour, S; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Machet, M; Malcles, J; Rander, J; Rosowsky, A; Titov, M; Zghiche, A; Antropov, I; Baffioni, S; Beaudette, F; Busson, P; Cadamuro, L; Chapon, E; Charlot, C; Davignon, O; Filipovic, N; Granier de Cassagnac, R; Jo, M; Lisniak, S; Mastrolorenzo, L; Miné, P; Naranjo, I N; Nguyen, M; Ochando, C; Ortona, G; Paganini, P; Pigard, P; Regnard, S; Salerno, R; Sauvan, J B; Sirois, Y; Strebler, T; Yilmaz, Y; Zabi, A; Agram, J-L; Andrea, J; Aubin, A; Bloch, D; Brom, J-M; Buttignol, M; Chabert, E C; Chanon, N; Collard, C; Conte, E; Coubez, X; Fontaine, J-C; Gelé, D; Goerlach, U; Goetzmann, C; Le Bihan, A-C; Merlin, J A; Skovpen, K; Van Hove, P; Gadrat, S; Beauceron, S; Bernet, C; Boudoul, G; Bouvier, E; Carrillo Montoya, C A; Chierici, R; Contardo, D; Courbon, B; Depasse, P; El Mamouni, H; Fan, J; Fay, J; Gascon, S; Gouzevitch, M; Ille, B; Lagarde, F; Laktineh, I B; Lethuillier, M; Mirabito, L; Pequegnot, A L; Perries, S; Ruiz Alvarez, J D; Sabes, D; Sgandurra, L; Sordini, V; Vander Donckt, M; Verdier, P; Viret, S; Toriashvili, T; Tsamalaidze, Z; Autermann, C; Beranek, S; Feld, L; Heister, A; Kiesel, M K; Klein, K; Lipinski, M; Ostapchuk, A; Preuten, M; Raupach, F; Schael, S; Schulte, J F; Verlage, T; Weber, H; Zhukov, V; Ata, M; Brodski, M; Dietz-Laursonn, E; Duchardt, D; Endres, M; Erdmann, M; Erdweg, S; Esch, T; 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Bunn, J; Chen, Y; Duarte, J; Mott, A; Newman, H B; Pena, C; Spiropulu, M; Vlimant, J R; Xie, S; Zhu, R Y; Andrews, M B; Azzolini, V; Calamba, A; Carlson, B; Ferguson, T; Paulini, M; Russ, J; Sun, M; Vogel, H; Vorobiev, I; Cumalat, J P; Ford, W T; Gaz, A; Jensen, F; Johnson, A; Krohn, M; Mulholland, T; Nauenberg, U; Stenson, K; Wagner, S R; Alexander, J; Chatterjee, A; Chaves, J; Chu, J; Dittmer, S; Eggert, N; Mirman, N; Nicolas Kaufman, G; Patterson, J R; Rinkevicius, A; Ryd, A; Skinnari, L; Soffi, L; Sun, W; Tan, S M; Teo, W D; Thom, J; Thompson, J; Tucker, J; Weng, Y; Wittich, P; Abdullin, S; Albrow, M; Apollinari, G; Banerjee, S; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Bolla, G; Burkett, K; Butler, J N; Cheung, H W K; Chlebana, F; Cihangir, S; Elvira, V D; Fisk, I; Freeman, J; Gottschalk, E; Gray, L; Green, D; Grünendahl, S; Gutsche, O; Hanlon, J; Hare, D; Harris, R M; Hasegawa, S; Hirschauer, J; Hu, Z; Jayatilaka, B; Jindariani, S; Johnson, M; Joshi, U; Klima, B; Kreis, B; Lammel, S; Linacre, J; Lincoln, D; Lipton, R; Liu, T; Lopes De Sá, R; Lykken, J; Maeshima, K; Marraffino, J M; Maruyama, S; Mason, D; McBride, P; Merkel, P; Mrenna, S; Nahn, S; Newman-Holmes, C; O'Dell, V; Pedro, K; Prokofyev, O; Rakness, G; Sexton-Kennedy, E; Soha, A; Spalding, W J; Spiegel, L; Strobbe, N; Taylor, L; Tkaczyk, S; Tran, N V; Uplegger, L; Vaandering, E W; Vernieri, C; Verzocchi, M; Vidal, R; Weber, H A; Whitbeck, A; Acosta, D; Avery, P; Bortignon, P; Bourilkov, D; Carnes, A; Carver, M; Curry, D; Das, S; Field, R D; Furic, I K; Gleyzer, S V; Konigsberg, J; Korytov, A; Kotov, K; Ma, P; Matchev, K; Mei, H; Milenovic, P; Mitselmakher, G; Rank, D; Rossin, R; Shchutska, L; Snowball, M; Sperka, D; Terentyev, N; Thomas, L; Wang, J; Wang, S; Yelton, J; Hewamanage, S; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Ackert, A; Adams, J R; Adams, T; Askew, A; Bein, S; Bochenek, J; Diamond, B; Haas, J; Hagopian, S; Hagopian, V; Johnson, K F; Khatiwada, A; Prosper, H; Weinberg, M; Baarmand, M M; Bhopatkar, V; Colafranceschi, S; Hohlmann, M; Kalakhety, H; Noonan, D; Roy, T; Yumiceva, F; Adams, M R; Apanasevich, L; Berry, D; Betts, R R; Bucinskaite, I; Cavanaugh, R; Evdokimov, O; Gauthier, L; Gerber, C E; Hofman, D J; Kurt, P; O'Brien, C; Sandoval Gonzalez, I D; Turner, P; Varelas, N; Wu, Z; Zakaria, M; Bilki, B; Clarida, W; Dilsiz, K; Durgut, S; Gandrajula, R P; Haytmyradov, M; Khristenko, V; Merlo, J-P; Mermerkaya, H; Mestvirishvili, A; Moeller, A; Nachtman, J; Ogul, H; Onel, Y; Ozok, F; Penzo, A; Snyder, C; Tiras, E; Wetzel, J; Yi, K; Anderson, I; Barnett, B A; Blumenfeld, B; Eminizer, N; Fehling, D; Feng, L; Gritsan, A V; Maksimovic, P; Martin, C; Osherson, M; Roskes, J; Sady, A; Sarica, U; Swartz, M; Xiao, M; Xin, Y; You, C; Baringer, P; Bean, A; Benelli, G; Bruner, C; Kenny, R P; Majumder, D; Malek, M; Murray, M; Sanders, S; Stringer, R; Wang, Q; Ivanov, A; Kaadze, K; Khalil, S; Makouski, M; Maravin, Y; Mohammadi, A; Saini, L K; Skhirtladze, N; Toda, S; Lange, D; Rebassoo, F; Wright, D; Anelli, C; Baden, A; Baron, O; Belloni, A; Calvert, B; Eno, S C; Ferraioli, C; Gomez, J A; Hadley, N J; Jabeen, S; Kellogg, R G; Kolberg, T; Kunkle, J; Lu, Y; Mignerey, A C; Shin, Y H; Skuja, A; Tonjes, M B; Tonwar, S C; Apyan, A; Barbieri, R; Baty, A; Bierwagen, K; Brandt, S; Busza, W; Cali, I A; Demiragli, Z; Di Matteo, L; Gomez Ceballos, G; Goncharov, M; Gulhan, D; Iiyama, Y; Innocenti, G M; Klute, M; Kovalskyi, D; Lai, Y S; Lee, Y-J; Levin, A; Luckey, P D; Marini, A C; Mcginn, C; Mironov, C; Narayanan, S; Niu, X; Paus, C; Roland, C; Roland, G; Salfeld-Nebgen, J; Stephans, G S F; Sumorok, K; Varma, M; Velicanu, D; Veverka, J; Wang, J; Wang, T W; Wyslouch, B; Yang, M; Zhukova, V; Dahmes, B; Evans, A; Finkel, A; Gude, A; Hansen, P; Kalafut, S; Kao, S C; Klapoetke, K; Kubota, Y; Lesko, Z; Mans, J; Nourbakhsh, S; Ruckstuhl, N; Rusack, R; Tambe, N; Turkewitz, J; Acosta, J G; Oliveros, S; Avdeeva, E; Bloom, K; Bose, S; Claes, D R; Dominguez, A; Fangmeier, C; Gonzalez Suarez, R; Kamalieddin, R; Knowlton, D; Kravchenko, I; Meier, F; Monroy, J; Ratnikov, F; Siado, J E; Snow, G R; Alyari, M; Dolen, J; George, J; Godshalk, A; Harrington, C; Iashvili, I; Kaisen, J; Kharchilava, A; Kumar, A; Rappoccio, S; Roozbahani, B; Alverson, G; Barberis, E; Baumgartel, D; Chasco, M; Hortiangtham, A; Massironi, A; Morse, D M; Nash, D; Orimoto, T; Teixeira De Lima, R; Trocino, D; Wang, R-J; Wood, D; Zhang, J; Bhattacharya, S; Hahn, K A; Kubik, A; Low, J F; Mucia, N; Odell, N; Pollack, B; Schmitt, M; Stoynev, S; Sung, K; Trovato, M; Velasco, M; Brinkerhoff, A; Dev, N; Hildreth, M; Jessop, C; Karmgard, D J; Kellams, N; Lannon, K; Marinelli, N; Meng, F; Mueller, C; Musienko, Y; Planer, M; Reinsvold, A; Ruchti, R; Smith, G; Taroni, S; Valls, N; Wayne, M; Wolf, M; Woodard, A; Antonelli, L; Brinson, J; Bylsma, B; Durkin, L S; Flowers, S; Hart, A; Hill, C; Hughes, R; Ji, W; Ling, T Y; Liu, B; Luo, W; Puigh, D; Rodenburg, M; Winer, B L; Wulsin, H W; Driga, O; Elmer, P; Hardenbrook, J; Hebda, P; Koay, S A; Lujan, P; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Palmer, C; Piroué, P; Saka, H; Stickland, D; Tully, C; Zuranski, A; Malik, S; Barker, A; Barnes, V E; Benedetti, D; Bortoletto, D; Gutay, L; Jha, M K; Jones, M; Jung, A W; Jung, K; Kumar, A; Miller, D H; Neumeister, N; Radburn-Smith, B C; Shi, X; Shipsey, I; Silvers, D; Sun, J; Svyatkovskiy, A; Wang, F; Xie, W; Xu, L; Parashar, N; Stupak, J; Adair, A; Akgun, B; Chen, Z; Ecklund, K M; Geurts, F J M; Guilbaud, M; Li, W; Michlin, B; Northup, M; Padley, B P; Redjimi, R; Roberts, J; Rorie, J; Tu, Z; Zabel, J; Betchart, B; Bodek, A; de Barbaro, P; Demina, R; Eshaq, Y; Ferbel, T; Galanti, M; Garcia-Bellido, A; Han, J; Harel, A; Hindrichs, O; Khukhunaishvili, A; Petrillo, G; Tan, P; Verzetti, M; Arora, S; Chou, J P; Contreras-Campana, C; Contreras-Campana, E; Ferencek, D; Gershtein, Y; Gray, R; Halkiadakis, E; Hidas, D; Hughes, E; Kaplan, S; Kunnawalkam Elayavalli, R; Lath, A; Nash, K; Panwalkar, S; Park, M; Salur, S; Schnetzer, S; Sheffield, D; Somalwar, S; Stone, R; Thomas, S; Thomassen, P; Walker, M; Foerster, M; Riley, G; Rose, K; Spanier, S; Bouhali, O; Castaneda Hernandez, A; Celik, A; Dalchenko, M; De Mattia, M; Delgado, A; Dildick, S; Eusebi, R; Gilmore, J; Huang, T; Kamon, T; Krutelyov, V; Mueller, R; Osipenkov, I; Pakhotin, Y; Patel, R; Perloff, A; Rose, A; Safonov, A; Tatarinov, A; Ulmer, K A; Akchurin, N; Cowden, C; Damgov, J; Dragoiu, C; Dudero, P R; Faulkner, J; Kunori, S; Lamichhane, K; Lee, S W; Libeiro, T; Undleeb, S; Volobouev, I; Appelt, E; Delannoy, A G; Greene, S; Gurrola, A; Janjam, R; Johns, W; Maguire, C; Mao, Y; Melo, A; Ni, H; Sheldon, P; Tuo, S; Velkovska, J; Xu, Q; Arenton, M W; Cox, B; Francis, B; Goodell, J; Hirosky, R; Ledovskoy, A; Li, H; Lin, C; Neu, C; Sinthuprasith, T; Sun, X; Wang, Y; Wolfe, E; Wood, J; Xia, F; Clarke, C; Harr, R; Karchin, P E; Kottachchi Kankanamge Don, C; Lamichhane, P; Sturdy, J; Belknap, D A; Carlsmith, D; Cepeda, M; Dasu, S; Dodd, L; Duric, S; Gomber, B; Grothe, M; Hall-Wilton, R; Herndon, M; Hervé, A; Klabbers, P; Lanaro, A; Levine, A; Long, K; Loveless, R; Mohapatra, A; Ojalvo, I; Perry, T; Pierro, G A; Polese, G; Ruggles, T; Sarangi, T; Savin, A; Sharma, A; Smith, N; Smith, W H; Taylor, D; Verwilligen, P; Woods, N

2016-04-29

Results on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270  nb^{-1}. The correlations are studied over a broad range of pseudorapidity (|η|<2.4) and over the full azimuth (ϕ) as a function of charged particle multiplicity and transverse momentum (p_{T}). In high-multiplicity events, a long-range (|Δη|>2.0), near-side (Δϕ≈0) structure emerges in the two-particle Δη-Δϕ correlation functions. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0correlation strength similar to that found in earlier pp data at sqrt[s]=7  TeV. The present measurement extends the study of near-side long-range correlations up to charged particle multiplicities N_{ch}∼180, a region so far unexplored in pp collisions. The observed long-range correlations are compared to those seen in pp, pPb, and PbPb collisions at lower collision energies.

Passive Acoustic Mapping with the Angular Spectrum Method

PubMed Central

Crake, Calum; McDannold, Nathan; Clement, Gregory T.

2017-01-01

In the present proof of principle study, we evaluated the homogenous angular spectrum method for passive acoustic mapping (AS-PAM) of microbubble oscillations using simulated and experimental data. In the simulated data we assessed the ability of AS-PAM to form 3D maps of a single and multiple point sources. Then, in the two dimensional limit, we compared the 2D maps from AS-PAM with alternative frequency and time domain passive acoustic mapping (FD- and TD-PAM) approaches. Finally, we assessed the ability of AS-PAM to visualize microbubble activity in vivo with data obtained during 8 different experiments of FUS-induced blood-brain barrier disruption in 3 nonhuman primates, using a clinical MR-guided FUS system. Our in silico results demonstrate AS-PAM can be used to perform 3D passive acoustic mapping. 2D AS-PAM as compared to FD- PAM and TD-PAM is 10 and 200 times faster respectively and has similar sensitivity, resolution, and localization accuracy, even when the noise was 10-fold higher than the signal. In-vivo, the AS-PAM reconstructions of emissions at frequency bands pertinent to the different types of microbubble oscillations were also found to be more sensitive than TD-PAM. AS-PAM of harmonic-only components predicted safe blood-brain barrier disruption, whereas AS-PAM of broadband emissions correctly identified MR-evident tissue damage. The disparity (3.2mm) in the location of the cavitation activity between the three methods was within their resolution limits. These data clearly demonstrate that AS-PAM is a sensitive and fast approach for PAM, thus providing a clinically relevant method to guide therapeutic ultrasound procedures. PMID:28026755

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p + Au collisions at s NN = 200 GeV

DOE PAGES

Aidala, C.; Akiba, Y.; Alfred, M.; ...

2017-03-24

Inmore » this paper, we present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow ν 2 in high-multiplicity p + Au collisions at s NN = 200 GeV. A comparison of these results to previous measurements in high-multiplicity d + Au and 3He + Au collisions demonstrates a relation between ν 2 and the initial collision eccentricity ε 2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured ν 2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. Finally, the set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.« less

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p + Au collisions at s NN = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aidala, C.; Akiba, Y.; Alfred, M.

Inmore » this paper, we present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow ν 2 in high-multiplicity p + Au collisions at s NN = 200 GeV. A comparison of these results to previous measurements in high-multiplicity d + Au and 3He + Au collisions demonstrates a relation between ν 2 and the initial collision eccentricity ε 2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured ν 2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. Finally, the set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.« less

A Very Fast and Angular Momentum Conserving Tree Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcello, Dominic C., E-mail: dmarce504@gmail.com

There are many methods used to compute the classical gravitational field in astrophysical simulation codes. With the exception of the typically impractical method of direct computation, none ensure conservation of angular momentum to machine precision. Under uniform time-stepping, the Cartesian fast multipole method of Dehnen (also known as the very fast tree code) conserves linear momentum to machine precision. We show that it is possible to modify this method in a way that conserves both angular and linear momenta.

Electronic structure and orientation relationship of Li nanoclusters embedded in MgO studied by depth-selective positron annihilation two-dimensional angular correlation

NASA Astrophysics Data System (ADS)

Falub, C. V.; Mijnarends, P. E.; Eijt, S. W.; van Huis, M. A.; van Veen, A.; Schut, H.

2002-08-01

Quantum-confined positrons are sensitive probes for determining the electronic structure of nanoclusters embedded in materials. In this work, a depth-selective positron annihilation 2D-ACAR (two-dimensional angular correlation of annihilation radiation) method is used to determine the electronic structure of Li nanoclusters formed by implantation of 1016-cm-2 30-keV 6Li ions in MgO (100) and (110) crystals and by subsequent annealing at 950 K. Owing to the difference between the positron affinities of lithium and MgO, the Li nanoclusters act as quantum dots for positrons. 2D-ACAR distributions for different projections reveal a semicoherent fitting of the embedded metallic Li nanoclusters to the host MgO lattice. Ab initio Korringa-Kohn-Rostoker calculations of the momentum density show that the anisotropies of the experimental distributions are consistent with an fcc crystal structure of the Li nanoclusters. The observed reduction of the width of the experimental 2D-ACAR distribution is attributed to positron trapping in vacancies associated with Li clusters. This work proposes a method for studying the electronic structure of metallic quantum dots embedded in an insulating material.

Angular width of the Cherenkov radiation with inclusion of multiple scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jian, E-mail: jzheng@ustc.edu.cn

2016-06-15

Visible Cherenkov radiation can offer a method of the measurement of the velocity of charged particles. The angular width of the radiation is important since it determines the resolution of the velocity measurement. In this article, the angular width of Cherenkov radiation with inclusion of multiple scattering is calculated through the path-integral method, and the analytical expressions are presented. The condition that multiple scattering processes dominate the angular distribution is obtained.

Capillary-scale direct measurement of hemoglobin concentration of erythrocytes using photothermal angular light scattering.

PubMed

Kim, Uihan; Song, Jaewoo; Lee, Donghak; Ryu, Suho; Kim, Soocheol; Hwang, Jaehyun; Joo, Chulmin

2015-12-15

We present a direct, rapid and chemical-free detection method for hemoglobin concentration ([Hb]), based on photothermal angular light scattering. The iron oxides contained in hemoglobin molecules exhibit high absorption of 532-nm light and generate heat under the illumination of 532-nm light, which subsequently alters the refractive index of blood. We measured this photothermal change in refractive index by employing angular light scattering spectroscopy with the goal of quantifying [Hb] in blood samples. Highly sensitive [Hb] measurement of blood samples was performed by monitoring the shifts in angularly dispersed scattering patterns from the blood-loaded microcapillary tubes. Our system measured [Hb] over the range of 0.35-17.9 g/dL with a detection limit of ~0.12 g/dL. Our sensor was characterized by excellent correlation with a reference hematology analyzer (r>0.96), and yielded a precision of 0.63 g/dL for a blood sample of 9.0 g/dL. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of angular momentum properties of photons emitted in fundamental atomic processes

NASA Astrophysics Data System (ADS)

Zaytsev, V. A.; Surzhykov, A. S.; Shabaev, V. M.; Stöhlker, Th.

2018-04-01

Many atomic processes result in the emission of photons. Analysis of the properties of emitted photons, such as energy and angular distribution as well as polarization, is regarded as a powerful tool for gaining more insight into the physics of corresponding processes. Another characteristic of light is the projection of its angular momentum upon propagation direction. This property has attracted a special attention over the past decades due to studies of twisted (or vortex) light beams. Measurements being sensitive to this projection may provide valuable information about the role of angular momentum in the fundamental atomic processes. Here we describe a simple theoretical method for determination of the angular momentum properties of the photons emitted in various atomic processes. This method is based on the evaluation of expectation value of the total angular momentum projection operator. To illustrate the method, we apply it to the textbook examples of plane-wave, spherical-wave, and Bessel light. Moreover, we investigate the projection of angular momentum for the photons emitted in the process of the radiative recombination with ionic targets. It is found that the recombination photons do carry a nonzero projection of the orbital angular momentum.

Alignment of angular velocity sensors for a vestibular prosthesis.

PubMed

Digiovanna, Jack; Carpaneto, Jacopo; Micera, Silvestro; Merfeld, Daniel M

2012-02-13

Vestibular prosthetics transmit angular velocities to the nervous system via electrical stimulation. Head-fixed gyroscopes measure angular motion, but the gyroscope coordinate system will not be coincident with the sensory organs the prosthetic replaces. Here we show a simple calibration method to align gyroscope measurements with the anatomical coordinate system. We benchmarked the method with simulated movements and obtain proof-of-concept with one healthy subject. The method was robust to misalignment, required little data, and minimal processing.

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p +Au collisions at √{sNN}=200 GeV

NASA Astrophysics Data System (ADS)

Aidala, C.; Akiba, Y.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Asano, H.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bandara, N. S.; Barish, K. N.; Bathe, S.; Bazilevsky, A.; Beaumier, M.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Blau, D. S.; Boer, M.; Bok, J. S.; Brooks, M. L.; Bryslawskyj, J.; Bumazhnov, V.; Butler, C.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Citron, Z.; Connors, M.; Cronin, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dion, A.; Dixit, D.; Do, J. H.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Elder, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukuda, Y.; Gal, C.; Gallus, P.; Garg, P.; Ge, H.; Giordano, F.; Goto, Y.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; He, X.; Hemmick, T. K.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Imai, K.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jezghani, M.; Ji, Z.; Jiang, X.; Johnson, B. M.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kang, J. H.; Kapukchyan, D.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Khachatryan, V.; Khanzadeev, A.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, M. H.; Kim, M.; Kincses, D.; Kistenev, E.; Klatsky, J.; Kline, P.; Koblesky, T.; Kotov, D.; Kudo, S.; Kurita, K.; Kwon, Y.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, S.; Leitch, M. J.; Leung, Y. H.; Lewis, N. A.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lovasz, K.; Lynch, D.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Mendoza, M.; Mignerey, A. C.; Mihalik, D. E.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Murakami, T.; Murata, J.; Nagai, K.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakano, K.; Nattrass, C.; Niida, T.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pantuev, V.; Papavassiliou, V.; Park, J. S.; Park, S.; Pate, S. F.; Patel, M.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richford, D.; Rinn, T.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Runchey, J.; Safonov, A. S.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Smith, K. L.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takeda, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Tarnai, G.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Towell, C. L.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vazquez-Carson, S.; Velkovska, J.; Virius, M.; Vrba, V.; Vukman, N.; Wang, X. R.; Wang, Z.; Watanabe, Y.; Watanabe, Y. S.; Wong, C. P.; Woody, C. L.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yoo, J. H.; Yoon, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zou, L.; Phenix Collaboration

2017-03-01

We present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow v2 in high-multiplicity p +Au collisions at √{s NN}=200 GeV. A comparison of these results to previous measurements in high-multiplicity d +Au and 3He+Au collisions demonstrates a relation between v2 and the initial collision eccentricity ɛ2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured v2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. The set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.

Bell’s measure and implementing quantum Fourier transform with orbital angular momentum of classical light

PubMed Central

Song, Xinbing; Sun, Yifan; Li, Pengyun; Qin, Hongwei; Zhang, Xiangdong

2015-01-01

We perform Bell’s measurement for the non-separable correlation between polarization and orbital angular momentum from the same classical vortex beam. The violation of Bell’s inequality for such a non-separable classical correlation has been demonstrated experimentally. Based on the classical vortex beam and non-quantum entanglement between the polarization and the orbital angular momentum, the Hadamard gates and conditional phase gates have been designed. Furthermore, a quantum Fourier transform has been implemented experimentally. PMID:26369424

Method for improving the angular resolution of a neutron scatter camera

DOEpatents

Mascarenhas, Nicholas; Marleau, Peter; Gerling, Mark; Cooper, Robert Lee; Mrowka, Stanley; Brennan, James S.

2012-12-25

An instrument that will directly image the fast fission neutrons from a special nuclear material source wherein the neutron detection efficiency is increased has been described. Instead of the previous technique that uses a time-of-flight (TOF) between 2 widely spaced fixed planes of neutron detectors to measure scatter neutron kinetic energy, we now use the recoil proton energy deposited in the second of the 2 scatter planes which can now be repositioned either much closer together or further apart. However, by doubling the separation distance between the 2 planes from 20 cm to a distance of 40 cm we improved the angular resolution of the detector from about 12.degree. to about 10.degree.. A further doubling of the separation distance to 80 cm provided an addition improvement in angular resolution of the detector to about 6.degree. without adding additional detectors or ancillary electronics. The distance between planes also may be dynamically changed using a suitable common technique such as a gear- or motor-drive to toggle between the various positions. The angular resolution of this new configuration, therefore, is increased at the expanse of detection sensitivity. However, the diminished sensitivity may be acceptable for those applications where the detector is able to interrogate a particular site for an extended period.

WGM resonators for studying orbital angular momentum of a photon, and methods

NASA Technical Reports Server (NTRS)

Matsko, Andrey B. (Inventor); Savchenkov, Anatoliy A. (Inventor); Maleki, Lute (Inventor); Strekalov, Dmitry V. (Inventor)

2009-01-01

An optical system, device, and method that are capable of generating high-order Bessel beams and determining the orbital angular momentum of at least one of the photons of a Bessel beam are provided. The optical system and device include a tapered waveguide having an outer surface defined by a diameter that varies along a longitudinal axis of the waveguide from a first end to an opposing second end. The optical system and device include a resonator that is arranged in optical communication with the first end of the tapered waveguide such that an evanescent field emitted from (i) the waveguide can be coupled with the resonator, or (ii) the resonator can be coupled with the waveguide.

Empirical source strength correlations for rans-based acoustic analogy methods

NASA Astrophysics Data System (ADS)

Kube-McDowell, Matthew Tyndall

JeNo is a jet noise prediction code based on an acoustic analogy method developed by Mani, Gliebe, Balsa, and Khavaran. Using the flow predictions from a standard Reynolds-averaged Navier-Stokes computational fluid dynamics solver, JeNo predicts the overall sound pressure level and angular spectra for high-speed hot jets over a range of observer angles, with a processing time suitable for rapid design purposes. JeNo models the noise from hot jets as a combination of two types of noise sources; quadrupole sources dependent on velocity fluctuations, which represent the major noise of turbulent mixing, and dipole sources dependent on enthalpy fluctuations, which represent the effects of thermal variation. These two sources are modeled by JeNo as propagating independently into the far-field, with no cross-correlation at the observer location. However, high-fidelity computational fluid dynamics solutions demonstrate that this assumption is false. In this thesis, the theory, assumptions, and limitations of the JeNo code are briefly discussed, and a modification to the acoustic analogy method is proposed in which the cross-correlation of the two primary noise sources is allowed to vary with the speed of the jet and the observer location. As a proof-of-concept implementation, an empirical correlation correction function is derived from comparisons between JeNo's noise predictions and a set of experimental measurements taken for the Air Force Aero-Propulsion Laboratory. The empirical correlation correction is then applied to JeNo's predictions of a separate data set of hot jets tested at NASA's Glenn Research Center. Metrics are derived to measure the qualitative and quantitative performance of JeNo's acoustic predictions, and the empirical correction is shown to provide a quantitative improvement in the noise prediction at low observer angles with no freestream flow, and a qualitative improvement in the presence of freestream flow. However, the results also demonstrate

Characterization of the angular memory effect of scattered light in biological tissues.

PubMed

Schott, Sam; Bertolotti, Jacopo; Léger, Jean-Francois; Bourdieu, Laurent; Gigan, Sylvain

2015-05-18

High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues and therefore grants access to superficial brain layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations ('angular memory effect') are of a very short range and should theoretically be only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range and thus the possible field-of-view by more than an order of magnitude compared to isotropic scattering for ∼1 mm thick tissue layers.

Ways to improve your correlation functions

NASA Technical Reports Server (NTRS)

Hamilton, A. J. S.

1993-01-01

This paper describes a number of ways to improve on the standard method for measuring the two-point correlation function of large scale structure in the Universe. Issues addressed are: (1) the problem of the mean density, and how to solve it; (2) how to estimate the uncertainty in a measured correlation function; (3) minimum variance pair weighting; (4) unbiased estimation of the selection function when magnitudes are discrete; and (5) analytic computation of angular integrals in background pair counts.

Demonstrating the Direction of Angular Velocity in Circular Motion

NASA Astrophysics Data System (ADS)

Demircioglu, Salih; Yurumezoglu, Kemal; Isik, Hakan

2015-09-01

Rotational motion is ubiquitous in nature, from astronomical systems to household devices in everyday life to elementary models of atoms. Unlike the tangential velocity vector that represents the instantaneous linear velocity (magnitude and direction), an angular velocity vector is conceptually more challenging for students to grasp. In physics classrooms, the direction of an angular velocity vector is taught by the right-hand rule, a mnemonic tool intended to aid memory. A setup constructed for instructional purposes may provide students with a more easily understood and concrete method to observe the direction of the angular velocity. This article attempts to demonstrate the angular velocity vector using the observable motion of a screw mounted to a remotely operated toy car.

[Dental arch form reverting by four-point method].

PubMed

Pan, Xiao-Gang; Qian, Yu-Fen; Weng, Si-En; Feng, Qi-Ping; Yu, Quan

2008-04-01

To explore a simple method of reverting individual dental arch form template for wire bending. Individual dental arch form was reverted by four-point method. By defining central point of bracket on bilateral lower second premolar and first molar, certain individual dental arch form could be generated. The arch form generating procedure was then be developed to computer software for printing arch form. Four-point method arch form was evaluated by comparing with direct model measurement on linear and angular parameters. The accuracy and reproducibility were assessed by paired t test and concordance correlation coefficient with Medcalc 9.3 software package. The arch form by four-point method was of good accuracy and reproducibility (linear concordance correlation coefficient was 0.9909 and angular concordance correlation coefficient was 0.8419). The dental arch form reverted by four-point method could reproduce the individual dental arch form.

Angular coherence in ultrasound imaging: Theory and applications

PubMed Central

Li, You Leo; Dahl, Jeremy J.

2017-01-01

The popularity of plane-wave transmits at multiple transmit angles for synthetic transmit aperture (or coherent compounding) has spawned a number of adaptations and new developments of ultrasonic imaging. However, the coherence properties of backscattered signals with plane-wave transmits at different angles are unknown and may impact a subset of these techniques. To provide a framework for the analysis of the coherence properties of such signals, this article introduces the angular coherence theory in medical ultrasound imaging. The theory indicates that the correlation function of such signals forms a Fourier transform pair with autocorrelation function of the receive aperture function. This conclusion can be considered as an extended form of the van Cittert Zernike theorem. The theory is validated with simulation and experimental results obtained on speckle targets. On the basis of the angular coherence of the backscattered wave, a new short-lag angular coherence beamformer is proposed and compared with an existing spatial-coherence-based beamformer. An application of the theory in phase shift estimation and speed of sound estimation is also presented. PMID:28372139

Demarcation of continental-oceanic transition zone using angular differences between gradients of geophysical fields

NASA Astrophysics Data System (ADS)

Jilinski, Pavel; Meju, Max A.; Fontes, Sergio L.

2013-10-01

The commonest technique for determination of the continental-oceanic crustal boundary or transition (COB) zone is based on locating and visually correlating bathymetric and potential field anomalies and constructing crustal models constrained by seismic data. In this paper, we present a simple method for spatial correlation of bathymetric and potential field geophysical anomalies. Angular differences between gradient directions are used to determine different types of correlation between gravity and bathymetric or magnetic data. It is found that the relationship between bathymetry and gravity anomalies can be correctly identified using this method. It is demonstrated, by comparison with previously published models for the southwest African margin, that this method enables the demarcation of the zone of transition from oceanic to continental crust assuming that this it is associated with geophysical anomalies, which can be correlated using gradient directions rather than magnitudes. We also applied this method, supported by 2-D gravity modelling, to the more complex Liberia and Cote d'Ivoire-Ghana sectors of the West African transform margin and obtained results that are in remarkable agreement with past predictions of the COB in that region. We suggest the use of this method for a first-pass interpretation as a prelude to rigorous modelling of the COB in frontier areas.

Study on optical 3D angular deformations measurement

NASA Astrophysics Data System (ADS)

Gao, Yang; Wang, Xingshu; Huang, Zongsheng; Yang, Jinliang

2013-12-01

3D angular deformations will be inevitable when ships are sailing, due to the changes of the environmental temperature and external stresses. The measurement of 3D angular deformations is one of the most critical and difficult issues in navy and shipbuilding industry around the world. In this paper, we propose an optical method to measure 3D ship angular deformations and discuss the measurement errors in detail. Theoretical analysis shows that the measured errors of the pitching and yawing deformations are induced by the installation errors of the image aperture, and the measured error of the rolling deformation depends on the subpixel location algorithm in image processing. It indicates that the measured errors of the optical measurement proposed in this paper are at the magnitude of angular seconds, when the elaborated installation and precise image processing technology are both performed.

Simulation of angular-resolved RABBITT measurements in noble-gas atoms

NASA Astrophysics Data System (ADS)

Bray, Alexander W.; Naseem, Faiza; Kheifets, Anatoli S.

2018-06-01

We simulate angular-resolved RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) measurements on valence shells of noble-gas atoms (Ne, Ar, Kr, and Xe). Our nonperturbative numerical simulation is based on solution of the time-dependent Schrödinger equation (TDSE) for a target atom driven by an ionizing XUV and dressing IR fields. From these simulations we extract the angular-dependent magnitude and phase of the RABBITT oscillations and deduce the corresponding angular anisotropy β parameter and Wigner time delay τW for the single XUV photon absorption that initiates the RABBITT process. Said β and τW parameters are compared with calculations in the random-phase approximation with exchange (RPAE), which includes intershell correlation. This comparison is used to test various effective potentials employed in the one-electron TDSE. In lighter atoms (Ne and Ar), several effective potentials are found to provide accurate simulations of RABBITT measurements for a wide range of photon energies up to 100 eV above the valence-shell threshold. In heavier atoms (Kr and Xe), the onset of strong correlation with the d shell restricts the validity of the single active electron approximation to several tens of eV above the valence-shell threshold.

Numerical method for high accuracy index of refraction estimation for spectro-angular surface plasmon resonance systems.

PubMed

Alleyne, Colin J; Kirk, Andrew G; Chien, Wei-Yin; Charette, Paul G

2008-11-24

An eigenvector analysis based algorithm is presented for estimating refractive index changes from 2-D reflectance/dispersion images obtained with spectro-angular surface plasmon resonance systems. High resolution over a large dynamic range can be achieved simultaneously. The method performs well in simulations with noisy data maintaining an error of less than 10(-8) refractive index units with up to six bits of noise on 16 bit quantized image data. Experimental measurements show that the method results in a much higher signal to noise ratio than the standard 1-D weighted centroid dip finding algorithm.

Effects of aggregate angularity on mix design characteristics and pavement performance.

DOT National Transportation Integrated Search

2009-12-01

This research targeted two primary purposes: to estimate current aggregate angularity test methods and to evaluate current : aggregate angularity requirements in the Nebraska asphalt mixture/pavement specification. To meet the first research : object...

Goal-based angular adaptivity applied to a wavelet-based discretisation of the neutral particle transport equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goffin, Mark A., E-mail: mark.a.goffin@gmail.com; Buchan, Andrew G.; Dargaville, Steven

2015-01-15

A method for applying goal-based adaptive methods to the angular resolution of the neutral particle transport equation is presented. The methods are applied to an octahedral wavelet discretisation of the spherical angular domain which allows for anisotropic resolution. The angular resolution is adapted across both the spatial and energy dimensions. The spatial domain is discretised using an inner-element sub-grid scale finite element method. The goal-based adaptive methods optimise the angular discretisation to minimise the error in a specific functional of the solution. The goal-based error estimators require the solution of an adjoint system to determine the importance to the specifiedmore » functional. The error estimators and the novel methods to calculate them are described. Several examples are presented to demonstrate the effectiveness of the methods. It is shown that the methods can significantly reduce the number of unknowns and computational time required to obtain a given error. The novelty of the work is the use of goal-based adaptive methods to obtain anisotropic resolution in the angular domain for solving the transport equation. -- Highlights: •Wavelet angular discretisation used to solve transport equation. •Adaptive method developed for the wavelet discretisation. •Anisotropic angular resolution demonstrated through the adaptive method. •Adaptive method provides improvements in computational efficiency.« less

Angular oversampling with temporally offset layers on multilayer detectors in computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjölin, Martin, E-mail: martin.sjolin@mi.physics.kth.se; Danielsson, Mats

2016-06-15

Purpose: Today’s computed tomography (CT) scanners operate at an increasingly high rotation speed in order to reduce motion artifacts and to fulfill the requirements of dynamic acquisition, e.g., perfusion and cardiac imaging, with lower angular sampling rate as a consequence. In this paper, a simple method for obtaining angular oversampling when using multilayer detectors in continuous rotation CT is presented. Methods: By introducing temporal offsets between the measurement periods of the different layers on a multilayer detector, the angular sampling rate can be increased by a factor equal to the number of layers on the detector. The increased angular samplingmore » rate reduces the risk of producing aliasing artifacts in the image. A simulation of a detector with two layers is performed to prove the concept. Results: The simulation study shows that aliasing artifacts from insufficient angular sampling are reduced by the proposed method. Specifically, when imaging a single point blurred by a 2D Gaussian kernel, the method is shown to reduce the strength of the aliasing artifacts by approximately an order of magnitude. Conclusions: The presented oversampling method is easy to implement in today’s multilayer detectors and has the potential to reduce aliasing artifacts in the reconstructed images.« less

Optical angular momentum and atoms

PubMed Central

2017-01-01

Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069766

Angular Rate Sensing with GyroWheel Using Genetic Algorithm Optimized Neural Networks.

PubMed

Zhao, Yuyu; Zhao, Hui; Huo, Xin; Yao, Yu

2017-07-22

GyroWheel is an integrated device that can provide three-axis control torques and two-axis angular rate sensing for small spacecrafts. Large tilt angle of its rotor and de-tuned spin rate lead to a complex and non-linear dynamics as well as difficulties in measuring angular rates. In this paper, the problem of angular rate sensing with the GyroWheel is investigated. Firstly, a simplified rate sensing equation is introduced, and the error characteristics of the method are analyzed. According to the analysis results, a rate sensing principle based on torque balance theory is developed, and a practical way to estimate the angular rates within the whole operating range of GyroWheel is provided by using explicit genetic algorithm optimized neural networks. The angular rates can be determined by the measurable values of the GyroWheel (including tilt angles, spin rate and torque coil currents), the weights and the biases of the neural networks. Finally, the simulation results are presented to illustrate the effectiveness of the proposed angular rate sensing method with GyroWheel.

Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging

PubMed Central

Yeh, Fang-Cheng; Verstynen, Timothy D.

2016-01-01

Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions. PMID:27683539

Correlated noise in the COBE DMR sky maps

NASA Technical Reports Server (NTRS)

Lineweaver, C. H.; Smoot, G. F.; Bennett, C. L.; Wright, E. L.; Tenorio, L.; Kogut, A.; Keegstra, P. B.; Hinshaw, G.; Banday, A. J.

1994-01-01

The Cosmic Background Explorer Satellite Differential Radiometer (COBE DMR) sky maps contain low-level correlated noise. We obtain estimates of the amplitude and pattern of the correlated noise from three techniques: angular averages of the covariance matrix, Monte Carlo simulations of two-point correlation functions and direct analysis of the DMR maps. The results from the three methods are mutually consistent. The noise covariance matrix of a DMR sky maps is diagonal to an accuracy of better than 1%. For a given sky pixel, the dominant noise covariance occure with the ring of pixels at an angular separation of 60 deg due to the 60 deg separation of the DMR horns. The mean covariance at 60 deg is 0.45%((sup +0.18)(sub -0.14)) of the mean variance. Additionally, the variance in a given pixel is 0.7% greater than would be expected from a single beam experiment with the same noise properties. Autocorrelation functions suffer from a approximately 1.5 sigma positive bias at 60 deg while cross-correlations have no bias. Published COBE DMR results are not significantly affected by correlated noise.

The clinical features of angular cheilitis occurring during orthodontic treatment: a multi-centre observational study.

PubMed

Cross, David; Eide, May L; Kotinas, Anastasios

2010-06-01

To report the prevalence and clinical features of angular cheilitis occurring in patients undergoing orthodontic treatment. Cross-sectional, observational study. Three centres were involved; Glasgow Dental Hospital and two specialist orthodontic practices, one in Scotland and one in Greece. Six hundred and sixty consecutive patients undergoing orthodontic treatment were examined over a 9 month period. The presence and absence of angular cheilitis was recorded. A six-point clinical scale was used to describe the clinical features of angular cheilitis when present. Chi-squared tests were used to investigate the association between the presence of angular cheilitis and oral hygiene level/appliance type. Eleven per cent of orthodontic patients in this Western European population, showed signs of angular cheilitis. No correlation was found between the presence of angular cheilitis and gender. Good oral hygiene was associated with a reduced prevalence (P<0.01). Angular cheilitis is a multifactorial condition that can occur in a small percentage of patients during orthodontic treatment. Good oral hygiene may be associated with a reduced risk. A new clinical grade of angular cheilitis is suggested that may help future research. Further studies are required to investigate the microbiological features associated with angular cheilitis occurring in orthodontic patients, as well as associations with medical conditions, such as asthma.

Factors influencing perceived angular velocity.

PubMed

Kaiser, M K; Calderone, J B

1991-11-01

The assumption that humans are able to perceive and process angular kinematics is critical to many structure-from-motion and optical flow models. The current studies investigate this sensitivity, and examine several factors likely to influence angular velocity perception. In particular, three factors are considered: (1) the extent to which perceived angular velocity is determined by edge transitions of surface elements, (2) the extent to which angular velocity estimates are influenced by instantaneous linear velocities of surface elements, and (3) whether element-velocity effects are related to three-dimensional (3-D) tangential velocities or to two-dimensional (2-D) image velocities. Edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities influenced perceived angular velocity; this bias was related to 2-D image velocity rather than 3-D tangential velocity. Despite these biases, however, judgments were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter was surprisingly good, for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

A method of evaluating quantitative magnetospheric field models by an angular parameter alpha

NASA Technical Reports Server (NTRS)

Sugiura, M.; Poros, D. J.

1979-01-01

The paper introduces an angular parameter, termed alpha, which represents the angular difference between the observed, or model, field and the internal model field. The study discusses why this parameter is chosen and demonstrates its usefulness by applying it to both observations and models. In certain areas alpha is more sensitive than delta-B (the difference between the magnitude of the observed magnetic field and that of the earth's internal field calculated from a spherical harmonic expansion) in expressing magnetospheric field distortions. It is recommended to use both alpha and delta-B in comparing models with observations.

Spacecraft angular velocity estimation algorithm for star tracker based on optical flow techniques

NASA Astrophysics Data System (ADS)

Tang, Yujie; Li, Jian; Wang, Gangyi

2018-02-01

An integrated navigation system often uses the traditional gyro and star tracker for high precision navigation with the shortcomings of large volume, heavy weight and high-cost. With the development of autonomous navigation for deep space and small spacecraft, star tracker has been gradually used for attitude calculation and angular velocity measurement directly. At the same time, with the dynamic imaging requirements of remote sensing satellites and other imaging satellites, how to measure the angular velocity in the dynamic situation to improve the accuracy of the star tracker is the hotspot of future research. We propose the approach to measure angular rate with a nongyro and improve the dynamic performance of the star tracker. First, the star extraction algorithm based on morphology is used to extract the star region, and the stars in the two images are matched according to the method of angular distance voting. The calculation of the displacement of the star image is measured by the improved optical flow method. Finally, the triaxial angular velocity of the star tracker is calculated by the star vector using the least squares method. The method has the advantages of fast matching speed, strong antinoise ability, and good dynamic performance. The triaxial angular velocity of star tracker can be obtained accurately with these methods. So, the star tracker can achieve better tracking performance and dynamic attitude positioning accuracy to lay a good foundation for the wide application of various satellites and complex space missions.

A Role for the Left Angular Gyrus in Episodic Simulation and Memory

PubMed Central

2017-01-01

Functional magnetic resonance imaging (fMRI) studies indicate that episodic simulation (i.e., imagining specific future experiences) and episodic memory (i.e., remembering specific past experiences) are associated with enhanced activity in a common set of neural regions referred to as the core network. This network comprises the hippocampus, medial prefrontal cortex, and left angular gyrus, among other regions. Because fMRI data are correlational, it is unknown whether activity increases in core network regions are critical for episodic simulation and episodic memory. In the current study, we used MRI-guided transcranial magnetic stimulation (TMS) to assess whether temporary disruption of the left angular gyrus would impair both episodic simulation and memory (16 participants, 10 females). Relative to TMS to a control site (vertex), disruption of the left angular gyrus significantly reduced the number of internal (i.e., episodic) details produced during the simulation and memory tasks, with a concomitant increase in external detail production (i.e., semantic, repetitive, or off-topic information), reflected by a significant detail by TMS site interaction. Difficulty in the simulation and memory tasks also increased after TMS to the left angular gyrus relative to the vertex. In contrast, performance in a nonepisodic control task did not differ statistically as a function of TMS site (i.e., number of free associates produced or difficulty in performing the free associate task). Together, these results are the first to demonstrate that the left angular gyrus is critical for both episodic simulation and episodic memory. SIGNIFICANCE STATEMENT Humans have the ability to imagine future episodes (i.e., episodic simulation) and remember episodes from the past (i.e., episodic memory). A wealth of neuroimaging studies have revealed that these abilities are associated with enhanced activity in a core network of neural regions, including the hippocampus, medial prefrontal

A Novel Permanent Magnetic Angular Acceleration Sensor

PubMed Central

Zhao, Hao; Feng, Hao

2015-01-01

Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2). Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability. PMID:26151217

Correlation plenoptic imaging

NASA Astrophysics Data System (ADS)

Pepe, Francesco V.; Di Lena, Francesco; Garuccio, Augusto; D'Angelo, Milena

2017-06-01

Plenoptic Imaging (PI) is a novel optical technique for achieving tridimensional imaging in a single shot. In conventional PI, a microlens array is inserted in the native image plane and the sensor array is moved behind the microlenses. On the one hand, the microlenses act as imaging pixels to reproduce the image of the scene; on the other hand, each microlens reproduces on the sensor array an image of the camera lens, thus providing the angular information associated with each imaging pixel. The recorded propagation direction is exploited, in post- processing, to computationally retrace the geometrical light path, thus enabling the refocusing of different planes within the scene, the extension of the depth of field of the acquired image, as well as the 3D reconstruction of the scene. However, a trade-off between spatial and angular resolution is built in the standard plenoptic imaging process. We demonstrate that the second-order spatio-temporal correlation properties of light can be exploited to overcome this fundamental limitation. Using two correlated beams, from either a chaotic or an entangled photon source, we can perform imaging in one arm and simultaneously obtain the angular information in the other arm. In fact, we show that the second order correlation function possesses plenoptic imaging properties (i.e., it encodes both spatial and angular information), and is thus characterized by a key re-focusing and 3D imaging capability. From a fundamental standpoint, the plenoptic application is the first situation where the counterintuitive properties of correlated systems are effectively used to beat intrinsic limits of standard imaging systems. From a practical standpoint, our protocol can dramatically enhance the potentials of PI, paving the way towards its promising applications.

Measuring Average Angular Velocity with a Smartphone Magnetic Field Sensor

ERIC Educational Resources Information Center

Pili, Unofre; Violanda, Renante

2018-01-01

The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper,…

A Computational Technique to Determine the Angular Displacement, Velocity and Momentum of a Human Body.

ERIC Educational Resources Information Center

Hay, James G.; Wilson, Barry D.

The angular momentum of a human body derived from both the angular velocity and angular displacement, utilizing cinematographic records has not been adequately assessed, prior to this study. Miller (1970) obtained the angular momentum but only during the airborne phase of activity. The method used by Ramey (1973) involved a force platform, but…

Angular rate optimal design for the rotary strapdown inertial navigation system.

PubMed

Yu, Fei; Sun, Qian

2014-04-22

Due to the characteristics of high precision for a long duration, the rotary strapdown inertial navigation system (RSINS) has been widely used in submarines and surface ships. Nowadays, the core technology, the rotating scheme, has been studied by numerous researchers. It is well known that as one of the key technologies, the rotating angular rate seriously influences the effectiveness of the error modulating. In order to design the optimal rotating angular rate of the RSINS, the relationship between the rotating angular rate and the velocity error of the RSINS was analyzed in detail based on the Laplace transform and the inverse Laplace transform in this paper. The analysis results showed that the velocity error of the RSINS depends on not only the sensor error, but also the rotating angular rate. In order to minimize the velocity error, the rotating angular rate of the RSINS should match the sensor error. One optimal design method for the rotating rate of the RSINS was also proposed in this paper. Simulation and experimental results verified the validity and superiority of this optimal design method for the rotating rate of the RSINS.

Angular Rate Optimal Design for the Rotary Strapdown Inertial Navigation System

PubMed Central

Yu, Fei; Sun, Qian

2014-01-01

Due to the characteristics of high precision for a long duration, the rotary strapdown inertial navigation system (RSINS) has been widely used in submarines and surface ships. Nowadays, the core technology, the rotating scheme, has been studied by numerous researchers. It is well known that as one of the key technologies, the rotating angular rate seriously influences the effectiveness of the error modulating. In order to design the optimal rotating angular rate of the RSINS, the relationship between the rotating angular rate and the velocity error of the RSINS was analyzed in detail based on the Laplace transform and the inverse Laplace transform in this paper. The analysis results showed that the velocity error of the RSINS depends on not only the sensor error, but also the rotating angular rate. In order to minimize the velocity error, the rotating angular rate of the RSINS should match the sensor error. One optimal design method for the rotating rate of the RSINS was also proposed in this paper. Simulation and experimental results verified the validity and superiority of this optimal design method for the rotating rate of the RSINS. PMID:24759115

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

PubMed

Li, Jian; Wu, Dan; Han, Yan

2016-09-30

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent "I-shape" is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

Linear and angular control of circular walking in healthy older adults and subjects with cerebellar ataxia.

PubMed

Goodworth, Adam D; Paquette, Caroline; Jones, Geoffrey Melvill; Block, Edward W; Fletcher, William A; Hu, Bin; Horak, Fay B

2012-05-01

Linear and angular control of trunk and leg motion during curvilinear navigation was investigated in subjects with cerebellar ataxia and age-matched control subjects. Subjects walked with eyes open around a 1.2-m circle. The relationship of linear to angular motion was quantified by determining the ratios of trunk linear velocity to trunk angular velocity and foot linear position to foot angular position. Errors in walking radius (the ratio of linear to angular motion) also were quantified continuously during the circular walk. Relative variability of linear and angular measures was compared using coefficients of variation (CoV). Patterns of variability were compared using power spectral analysis for the trunk and auto-covariance analysis for the feet. Errors in radius were significantly increased in patients with cerebellar damage as compared to controls. Cerebellar subjects had significantly larger CoV of feet and trunk in angular, but not linear, motion. Control subjects also showed larger CoV in angular compared to linear motion of the feet and trunk. Angular and linear components of stepping differed in that angular, but not linear, foot placement had a negative correlation from one stride to the next. Thus, walking in a circle was associated with more, and a different type of, variability in angular compared to linear motion. Results are consistent with increased difficulty of, and role of the cerebellum in, control of angular trunk and foot motion for curvilinear locomotion.

Angular momentum of dwarf galaxies

NASA Astrophysics Data System (ADS)

Kurapati, Sushma; Chengalur, Jayaram N.; Pustilnik, Simon; Kamphuis, Peter

2018-05-01

Mass and specific angular momentum are two fundamental physical parameters of galaxies. We present measurements of the baryonic mass and specific angular momentum of 11 void dwarf galaxies derived from neutral hydrogen (HI) synthesis data. Rotation curves were measured using 3D and 2D tilted ring fitting routines, and the derived curves generally overlap within the error bars, except in the central regions where, as expected, the 3D routines give steeper curves. The specific angular momentum of void dwarfs is found to be high compared to an extrapolation of the trends seen for higher mass bulge-less spirals, but comparable to that of other dwarf irregular galaxies that lie outside of voids. As such, our data show no evidence for a dependence of the specific angular momentum on the large scale environment. Combining our data with the data from the literature, we find a baryonic threshold of ˜109.1 M⊙ for this increase in specific angular momentum. Interestingly, this threshold is very similar to the mass threshold below which the galaxy discs start to become systematically thicker. This provides qualitative support to the suggestion that the thickening of the discs, as well as the increase in specific angular momentum, are both results of a common physical mechanism, such as feedback from star formation. Quantitatively, however, the amount of star formation observed in our dwarfs appears insufficient to produce the observed increase in specific angular momentum. It is hence likely that other processes, such as cold accretion of high angular momentum gas, also play a role in increasing the specific angular momentum.

Read-only high accuracy volume holographic optical correlator

NASA Astrophysics Data System (ADS)

Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2011-10-01

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

Alignment of gold nanorods by angular photothermal depletion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Adam B.; Chow, Timothy T. Y.; Chon, James W. M., E-mail: jchon@swin.edu.au

2014-02-24

In this paper, we demonstrate that a high degree of alignment can be imposed upon randomly oriented gold nanorod films by angular photothermal depletion with linearly polarized laser irradiation. The photothermal reshaping of gold nanorods is observed to follow quadratic melting model rather than the threshold melting model, which distorts the angular and spectral hole created on 2D distribution map of nanorods to be an open crater shape. We have accounted these observations to the alignment procedures and demonstrated good agreement between experiment and simulations. The use of multiple laser depletion wavelengths allowed alignment criteria over a large range ofmore » aspect ratios, achieving 80% of the rods in the target angular range. We extend the technique to demonstrate post-alignment in a multilayer of randomly oriented gold nanorod films, with arbitrary control of alignment shown across the layers. Photothermal angular depletion alignment of gold nanorods is a simple, promising post-alignment method for creating future 3D or multilayer plasmonic nanorod based devices and structures.« less

Angular momentum transport with twisted exciton wave packets

NASA Astrophysics Data System (ADS)

Zang, Xiaoning; Lusk, Mark T.

2017-10-01

A chain of cofacial molecules with CN or CN h symmetry supports excitonic states with a screwlike structure. These can be quantified with the combination of an axial wave number and an azimuthal winding number. Combinations of these states can be used to construct excitonic wave packets that spiral down the chain with well-determined linear and angular momenta. These twisted exciton wave packets can be created and annihilated using laser pulses, and their angular momentum can be optically modified during transit. This allows for the creation of optoexcitonic circuits in which information, encoded in the angular momentum of light, is converted into excitonic wave packets that can be manipulated, transported, and then reemitted. A tight-binding paradigm is used to demonstrate the key ideas. The approach is then extended to quantify the evolution of twisted exciton wave packets in a many-body, multilevel time-domain density functional theory setting. In both settings, numerical methods are developed that allow the site-to-site transfer of angular momentum to be quantified.

Understanding deformation with high angular resolution electron backscatter diffraction (HR-EBSD)

NASA Astrophysics Data System (ADS)

Britton, T. B.; Hickey, J. L. R.

2018-01-01

High angular resolution electron backscatter diffraction (HR-EBSD) affords an increase in angular resolution, as compared to ‘conventional’ Hough transform based EBSD, of two orders of magnitude, enabling measurements of relative misorientations of 1 x 10-4 rads (~ 0.006°) and changes in (deviatoric) lattice strain with a precision of 1 x 10-4. This is achieved through direct comparison of two or more diffraction patterns using sophisticated cross-correlation based image analysis routines. Image shifts between zone axes in the two-correlated diffraction pattern are measured with sub-pixel precision and this realises the ability to measure changes in interplanar angles and lattice orientation with a high degree of sensitivity. These shifts are linked to strains and lattice rotations through simple geometry. In this manuscript, we outline the basis of the technique and two case studies that highlight its potential to tackle real materials science challenges, such as deformation patterning in polycrystalline alloys.

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils

PubMed Central

Li, Jian; Wu, Dan; Han, Yan

2016-01-01

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent “I-shape” is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation. PMID:27706039

Enhanced angular overlap model for nonmetallic f -electron systems

NASA Astrophysics Data System (ADS)

Gajek, Z.

2005-07-01

An efficient method of interpretation of the crystal field effect in nonmetallic f -electron systems, the enhanced angular overlap model (EAOM), is presented. The method is established on the ground of perturbation expansion of the effective Hamiltonian for localized electrons and first-principles calculations related to available experimental data. The series of actinide compounds AO2 , oxychalcogenides AOX , and dichalcogenides UX2 where X=S ,Se,Te and A=U ,Np serve as probes of the effectiveness of the proposed method. An idea is to enhance the usual angular overlap model with ab initio calculations of those contributions to the crystal field potential, which cannot be represented by the usual angular overlap model (AOM). The enhancement leads to an improved fitting and makes the approach intrinsically coherent. In addition, the ab initio calculations of the main, AOM-consistent part of the crystal field potential allows one to fix the material-specific relations for the EAOM parameters in the effective Hamiltonian. Consequently, the electronic structure interpretation based on EAOM can be extended to systems of the lowest point symmetries or/and deficient experimental data. Several examples illustrating the promising capabilities of EAOM are given.

Angular default mode network connectivity across working memory load.

PubMed

Vatansever, D; Manktelow, A E; Sahakian, B J; Menon, D K; Stamatakis, E A

2017-01-01

Initially identified during no-task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large-scale brain networks. Nevertheless, its contribution to whole-brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI-based n-back paradigm with parametric increases in difficulty. Using a voxel-wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n-back task load. Subsequent seed-based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large-scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n-back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41-52, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Angular velocity discrimination

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.

1990-01-01

Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

A Role for the Left Angular Gyrus in Episodic Simulation and Memory.

PubMed

Thakral, Preston P; Madore, Kevin P; Schacter, Daniel L

2017-08-23

Functional magnetic resonance imaging (fMRI) studies indicate that episodic simulation (i.e., imagining specific future experiences) and episodic memory (i.e., remembering specific past experiences) are associated with enhanced activity in a common set of neural regions referred to as the core network. This network comprises the hippocampus, medial prefrontal cortex, and left angular gyrus, among other regions. Because fMRI data are correlational, it is unknown whether activity increases in core network regions are critical for episodic simulation and episodic memory. In the current study, we used MRI-guided transcranial magnetic stimulation (TMS) to assess whether temporary disruption of the left angular gyrus would impair both episodic simulation and memory (16 participants, 10 females). Relative to TMS to a control site (vertex), disruption of the left angular gyrus significantly reduced the number of internal (i.e., episodic) details produced during the simulation and memory tasks, with a concomitant increase in external detail production (i.e., semantic, repetitive, or off-topic information), reflected by a significant detail by TMS site interaction. Difficulty in the simulation and memory tasks also increased after TMS to the left angular gyrus relative to the vertex. In contrast, performance in a nonepisodic control task did not differ statistically as a function of TMS site (i.e., number of free associates produced or difficulty in performing the free associate task). Together, these results are the first to demonstrate that the left angular gyrus is critical for both episodic simulation and episodic memory. SIGNIFICANCE STATEMENT Humans have the ability to imagine future episodes (i.e., episodic simulation) and remember episodes from the past (i.e., episodic memory). A wealth of neuroimaging studies have revealed that these abilities are associated with enhanced activity in a core network of neural regions, including the hippocampus, medial prefrontal

DVL Angular Velocity Recorder

NASA Technical Reports Server (NTRS)

Liebe, Wolfgang

1944-01-01

In many studies, especially of nonstationary flight motion, it is necessary to determine the angular velocities at which the airplane rotates about its various axes. The three-component recorder is designed to serve this purpose. If the angular velocity for one flight attitude is known, other important quantities can be derived from its time rate of change, such as the angular acceleration by differentiations, or - by integration - the angles of position of the airplane - that is, the angles formed by the airplane axes with the axis direction presented at the instant of the beginning of the motion that is to be investigated.

A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

NASA Astrophysics Data System (ADS)

Leader, Elliot

2018-04-01

The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.

Angular Spacing Control for Segmented Data Pages in Angle-Multiplexed Holographic Memory

NASA Astrophysics Data System (ADS)

Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Kikuchi, Hiroshi; Shimidzu, Naoki; Ando, Toshio; Masaki, Kazuyoshi; Shimizu, Takehiro

2011-09-01

To improve the recording density of angle-multiplexed holographic memory, it is effective to increase the numerical aperture of the lens and to shorten the wavelength of the laser source as well as to increase the multiplexing number. The angular selectivity of a hologram, which determines the multiplexing number, is dependent on the incident angle of not only the reference beam but also the signal beam to the holographic recording medium. The actual signal beam, which is a convergent or divergent beam, is regarded as the sum of plane waves that have different propagation directions, angular selectivities, and optimal angular spacings. In this paper, focusing on the differences in the optimal angular spacing, we proposed a method to control the angular spacing for each segmented data page. We investigated the angular selectivity of a hologram and crosstalk for segmented data pages using numerical simulation. The experimental results showed a practical bit-error rate on the order of 10-3.

Spectral collocation method with a flexible angular discretization scheme for radiative transfer in multi-layer graded index medium

NASA Astrophysics Data System (ADS)

Wei, Linyang; Qi, Hong; Sun, Jianping; Ren, Yatao; Ruan, Liming

2017-05-01

The spectral collocation method (SCM) is employed to solve the radiative transfer in multi-layer semitransparent medium with graded index. A new flexible angular discretization scheme is employed to discretize the solid angle domain freely to overcome the limit of the number of discrete radiative direction when adopting traditional SN discrete ordinate scheme. Three radial basis function interpolation approaches, named as multi-quadric (MQ), inverse multi-quadric (IMQ) and inverse quadratic (IQ) interpolation, are employed to couple the radiative intensity at the interface between two adjacent layers and numerical experiments show that MQ interpolation has the highest accuracy and best stability. Variable radiative transfer problems in double-layer semitransparent media with different thermophysical properties are investigated and the influence of these thermophysical properties on the radiative transfer procedure in double-layer semitransparent media is also analyzed. All the simulated results show that the present SCM with the new angular discretization scheme can predict the radiative transfer in multi-layer semitransparent medium with graded index efficiently and accurately.

Non-isotropic noise correlation in PET data reconstructed by FBP but not by OSEM demonstrated using auto-correlation function.

PubMed

Razifar, Pasha; Lubberink, Mark; Schneider, Harald; Långström, Bengt; Bengtsson, Ewert; Bergström, Mats

2005-05-13

BACKGROUND: Positron emission tomography (PET) is a powerful imaging technique with the potential of obtaining functional or biochemical information by measuring distribution and kinetics of radiolabelled molecules in a biological system, both in vitro and in vivo. PET images can be used directly or after kinetic modelling to extract quantitative values of a desired physiological, biochemical or pharmacological entity. Because such images are generally noisy, it is essential to understand how noise affects the derived quantitative values. A pre-requisite for this understanding is that the properties of noise such as variance (magnitude) and texture (correlation) are known. METHODS: In this paper we explored the pattern of noise correlation in experimentally generated PET images, with emphasis on the angular dependence of correlation, using the autocorrelation function (ACF). Experimental PET data were acquired in 2D and 3D acquisition mode and reconstructed by analytical filtered back projection (FBP) and iterative ordered subsets expectation maximisation (OSEM) methods. The 3D data was rebinned to a 2D dataset using FOurier REbinning (FORE) followed by 2D reconstruction using either FBP or OSEM. In synthetic images we compared the ACF results with those from covariance matrix. The results were illustrated as 1D profiles and also visualized as 2D ACF images. RESULTS: We found that the autocorrelation images from PET data obtained after FBP were not fully rotationally symmetric or isotropic if the object deviated from a uniform cylindrical radioactivity distribution. In contrast, similar autocorrelation images obtained after OSEM reconstruction were isotropic even when the phantom was not circular. Simulations indicated that the noise autocorrelation is non-isotropic in images created by FBP when the level of noise in projections is angularly variable. Comparison between 1D cross profiles on autocorrelation images obtained by FBP reconstruction and covariance

Hunting the Gluon Orbital Angular Momentum at the Electron-Ion Collider.

PubMed

Ji, Xiangdong; Yuan, Feng; Zhao, Yong

2017-05-12

Applying the connection between the parton Wigner distribution and orbital angular momentum (OAM), we investigate the probe of the gluon OAM in hard scattering processes at the planned electron-ion collider. We show that the single longitudinal target-spin asymmetry in the hard diffractive dijet production is very sensitive to the gluon OAM distribution. The associated spin asymmetry leads to a characteristic azimuthal angular correlation of sin(ϕ_{q}-ϕ_{Δ}), where ϕ_{Δ} and ϕ_{q} are the azimuthal angles of the proton momentum transfer and the relative transverse momentum between the quark-antiquark pair. This study may motivate a first measurement of the gluon OAM in the proton spin sum rule.

Angular Positioning Sensor for Space Mechanisms

NASA Astrophysics Data System (ADS)

Steiner, Nicolas; Chapuis, Dominique

2013-09-01

Angular position sensors are used on various rotating mechanisms such as solar array drive mechanisms, antenna pointing mechanisms, scientific instruments, motors or actuators.Now a days, potentiometers and encoders are mainly used for angular measurement purposes. Both of them have their own pros and cons.As alternative, Ruag Space Switzerland Nyon (RSSN) is developing and qualifying two innovative technologies of angular position sensors which offer easy implementation, medium to very high lifetime and high flexibility with regards to the output signal shape/type.The Brushed angular position sensor uses space qualified processes which are already flying on RSSN's sliprings for many years. A large variety of output signal shape can be implemented to fulfill customer requirements (digital, analog, customized, etc.).The contactless angular position sensor consists in a new radiation hard Application Specific Integrated Circuit (ASIC) based on the Hall effect and providing the angular position without complex processing algorithm.

Precise measurement of the angular correlation parameter aβν in the β decay of 35Ar with LPCTrap

NASA Astrophysics Data System (ADS)

Fabian, X.; Ban, G.; Boussaïd, R.; Breitenfeldt, M.; Couratin, C.; Delahaye, P.; Durand, D.; Finlay, P.; Fléchard, X.; Guillon, B.; Lemière, Y.; Leredde, A.; Liénard, E.; Méry, A.; Naviliat-Cuncic, O.; Pierre, E.; Porobic, T.; Quéméner, G.; Rodríguez, D.; Severijns, N.; Thomas, J. C.; Van Gorp, S.

2014-03-01

Precise measurements in the β decay of the 35Ar nucleus enable to search for deviations from the Standard Model (SM) in the weak sector. These measurements enable either to check the CKM matrix unitarity or to constrain the existence of exotic currents rejected in the V-A theory of the SM. For this purpose, the β-ν angular correlation parameter, aβν, is inferred from a comparison between experimental and simulated recoil ion time-of-flight distributions following the quasi-pure Fermi transition of 35Ar1+ ions confined in the transparent Paul trap of the LPCTrap device at GANIL. During the last experiment, 1.5×106 good events have been collected, which corresponds to an expected precision of less than 0.5% on the aβν value. The required simulation is divided between the use of massive GPU parallelization and the GEANT4 toolkit for the source-cloud kinematics and the tracking of the decay products.

Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p + p collisions at s = 510 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adare, A.; Aidala, C.; Ajitanand, N. N.

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at √s=510 GeV. Correlations of charged hadrons of 0.7T<10 GeV/c with π 0 mesons of 4T<15 GeV/c or isolated direct photons of 7T direct photon or π 0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pmore » $$trig\\atop{T}$$). The Gaussian widths and root mean square of p out are reported as a function of the interaction hard scale p$$trig\\atop{T}$$ to investigate possible transverse-momentum-dependent evolution differences between the π 0-h ± and direct photon-h ± correlations and factorization breaking effects. The widths are found to decrease with p$$trig\\atop{T}$$, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p+p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.« less

Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p + p collisions at s = 510 GeV

DOE PAGES

Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

2017-04-04

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at √s=510 GeV. Correlations of charged hadrons of 0.7T<10 GeV/c with π 0 mesons of 4T<15 GeV/c or isolated direct photons of 7T direct photon or π 0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pmore » $$trig\\atop{T}$$). The Gaussian widths and root mean square of p out are reported as a function of the interaction hard scale p$$trig\\atop{T}$$ to investigate possible transverse-momentum-dependent evolution differences between the π 0-h ± and direct photon-h ± correlations and factorization breaking effects. The widths are found to decrease with p$$trig\\atop{T}$$, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p+p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.« less

Forming disc galaxies in major mergers - III. The effect of angular momentum on the radial density profiles of disc galaxies

NASA Astrophysics Data System (ADS)

Peschken, N.; Athanassoula, E.; Rodionov, S. A.

2017-06-01

We study the effect of angular momentum on the surface density profiles of disc galaxies, using high-resolution simulations of major mergers whose remnants have downbending radial density profiles (type II). As described in the previous papers of this series, in this scenario, most of the disc mass is acquired after the collision via accretion from a hot gaseous halo. We find that the inner and outer disc scalelengths, as well as the break radius, correlate with the total angular momentum of the initial merging system, and are larger for high-angular momentum systems. We follow the angular momentum redistribution in our simulated galaxies, and find that like the mass, the disc angular momentum is acquired via accretion, I.e. to the detriment of the gaseous halo. Furthermore, high-angular momentum systems give more angular momentum to their discs, which directly affects their radial density profile. Adding simulations of isolated galaxies to our sample, we find that the correlations are valid also for disc galaxies evolved in isolation. We show that the outer part of the disc at the end of the simulation is populated mainly by inside-out stellar migration, and that in galaxies with higher angular momentum, stars travel radially further out. This, however, does not mean that outer disc stars (in type II discs) were mostly born in the inner disc. Indeed, generally the break radius increases over time, and not taking this into account leads to overestimating the number of stars born in the inner disc.

SU-E-T-472: Improvement of IMRT QA Passing Rate by Correcting Angular Dependence of MatriXX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Q; Watkins, W; Kim, T

2015-06-15

Purpose: Multi-channel planar detector arrays utilized for IMRT-QA, such as the MatriXX, exhibit an incident-beam angular dependent response which can Result in false-positive gamma-based QA results, especially for helical tomotherapy plans which encompass the full range of beam angles. Although MatriXX can use with gantry angle sensor to provide automatically angular correction, this sensor does not work with tomotherapy. The purpose of the study is to reduce IMRT-QA false-positives by correcting for the MatriXX angular dependence. Methods: MatriXX angular dependence was characterized by comparing multiple fixed-angle irradiation measurements with corresponding TPS computed doses. For 81 Tomo-helical IMRT-QA measurements, two differentmore » correction schemes were tested: (1) A Monte-Carlo dose engine was used to compute MatriXX signal based on the angular-response curve. The computed signal was then compared with measurement. (2) Uncorrected computed signal was compared with measurements uniformly scaled to account for the average angular dependence. Three scaling factor (+2%, +2.5%, +3%) were tested. Results: The MatriXX response is 8% less than predicted for a PA beam even when the couch is fully accounted for. Without angular correction, only 67% of the cases pass the >90% points γ<1 (3%, 3mm). After full angular correction, 96% of the cases pass the criteria. Of three scaling factors, +2% gave the highest passing rate (89%), which is still less than the full angular correction method. With a stricter γ(2%,3mm) criteria, the full angular correction method was still able to achieve the 90% passing rate while the scaling method only gives 53% passing rate. Conclusion: Correction for the MatriXX angular dependence reduced the false-positives rate of our IMRT-QA process. It is necessary to correct for the angular dependence to achieve the IMRT passing criteria specified in TG129.« less

Asteroid orbit fitting with radar and angular observations

NASA Astrophysics Data System (ADS)

Baturin, A. P.

2013-12-01

The asteroid orbit fitting problem using their radar and angular observations has been considered. The problem was solved in a standanrd way by means of minimization of weighted sum of squares of residuals. In the orbit fitting both kinds of radar observa-tions have been used: the observations of time delays and of Doppler frequency shifts. The weight for angular observations has been set the same for all of them and has been determined as inverse mean-square residual obtained in the orbit fitting using just angular observations. The weights of radar observations have been set as inverse squared errors of these observations published together with them in the Minor Planet Center electronical circulars (MPECs). For the orbit fitting some five asteroids have been taken from these circulars. The asteroids have been chosen fulfilling the requirement of more than six radar observations of them to be available. The asteroids are 1950 DA, 1999 RQ36, 2002 NY40, 2004 DC and 2005 EU2. Several orbit fittings for these aster-oids have been done: with just angular observations; with just radar observations; with both angular and radar observations. The obtained results are quite acceptable because in the last case the mean-square angular residuals are approximately equal to the same ones obtained in the fitting with just angular observations. As to radar observations mean-square residuals, the time delay residuals for three asteroids do not exceed 1 μs, for two others ˜ 10 μs and the Doppler shift residuals for three asteroids do not exceed 1 Hz, for two others ˜ 10 Hz. The motion equations included perturbations from 9 planets and the Moon using their ephemerides DE422. The numerical integration has been performed with Everhart 27-order method with variable step. All calculations have been exe-cuted to a 34-digit decimal precision (i.e. using 128-bit floating-point numbers). Further, the sizes of confidence ellipsoids of im-proved orbit parameters have been compared. It

Variation in Angular Velocity and Angular Acceleration of a Particle in Rectilinear Motion

ERIC Educational Resources Information Center

Mashood, K. K.; Singh, V. A.

2012-01-01

We discuss the angular velocity ([image omitted]) and angular acceleration ([image omitted]) associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a…

Arbitrary spin-to-orbital angular momentum conversion of light

NASA Astrophysics Data System (ADS)

Devlin, Robert C.; Ambrosio, Antonio; Rubin, Noah A.; Mueller, J. P. Balthasar; Capasso, Federico

2017-11-01

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to-orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

A double-correlation tremor-location method

NASA Astrophysics Data System (ADS)

Li, Ka Lok; Sgattoni, Giulia; Sadeghisorkhani, Hamzeh; Roberts, Roland; Gudmundsson, Olafur

2017-02-01

A double-correlation method is introduced to locate tremor sources based on stacks of complex, doubly-correlated tremor records of multiple triplets of seismographs back projected to hypothetical source locations in a geographic grid. Peaks in the resulting stack of moduli are inferred source locations. The stack of the moduli is a robust measure of energy radiated from a point source or point sources even when the velocity information is imprecise. Application to real data shows how double correlation focuses the source mapping compared to the common single correlation approach. Synthetic tests demonstrate the robustness of the method and its resolution limitations which are controlled by the station geometry, the finite frequency of the signal, the quality of the used velocity information and noise level. Both random noise and signal or noise correlated at time shifts that are inconsistent with the assumed velocity structure can be effectively suppressed. Assuming a surface wave velocity, we can constrain the source location even if the surface wave component does not dominate. The method can also in principle be used with body waves in 3-D, although this requires more data and seismographs placed near the source for depth resolution.

Microstructural and hardness changes in aluminum alloy Al-7075: Correlating machining and equal channel angular pressing

NASA Astrophysics Data System (ADS)

Imbrogno, Stano; Segebade, Eric; Fellmeth, Andreas; Gerstenmeyer, Michael; Zanger, Frederik; Schulze, Volker; Umbrello, Domenico

2017-10-01

Recently, the study and understanding of surface integrity of various materials after machining is becoming one of the interpretative keys to quantify a product's quality and life cycle performance. The possibility to provide fundamental details about the mechanical response and the behavior of the affected material layers caused by thermo-mechanical loads resulting from machining operations can help the designer to produce parts with superior quality. The aim of this work is to study the experimental outcomes obtained from orthogonal cutting tests and a Severe Plastic Deformation (SPD) process known as Equal Channel Angular Pressing (ECAP) in order to find possible links regarding induced microstructural and hardness changes between machined surface layer and SPD-bulk material for Al-7075. This scientific investigation aims to establish the basis for an innovative method to study and quantify metallurgical phenomena that occur beneath the machined surface of bulk material.

Angular behavior of synchrotron radiation harmonics.

PubMed

Bagrov, V G; Bulenok, V G; Gitman, D M; Jara, Jose Acosta; Tlyachev, V B; Jarovoi, A T

2004-04-01

The detailed analysis of angular dependence of the synchrotron radiation (SR) is presented. Angular distributions of linear and circular polarization integrated over all harmonics, well known for relativistic electron energies, are extended to include radiation from electrons that are not fully relativistic. In particular, we analyze the angular dependence of the integral SR intensity and peculiarities of the angular dependence of the first harmonics SR. Studying spectral SR intensities, we have discovered their unexpected angular behavior, completely different from that of the integral SR intensity; namely, for any given synchrotron frequency, maxima of the spectral SR intensities recede from the orbit plane with increasing particle energy. Thus, in contrast with the integral SR intensity, the spectral ones have the tendency to deconcentrate themselves on the orbit plane.

Unveiling Angular Momentum

NASA Astrophysics Data System (ADS)

Robinson, Stephen

2015-03-01

Angular momentum is a notoriously difficult concept to grasp. Visualization often requires three-dimensional pictures of vectors pointing in seemingly arbitrary directions. A simple student-run laboratory experiment coupled with intuitive explanations by an instructor can clear up some of the inherent ambiguity of rotational motion. Specifically, the precessional period of a suspended spinning bicycle wheel can be related to the spinning frequency through a simple algebraic expression. An explanation of this precession apart from the concept of angular momentum will be given.

Factors influencing perceived angular velocity

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Calderone, Jack B.

1991-01-01

Angular velocity perception is examined for rotations both in depth and in the image plane and the influence of several object properties on this motion parameter is explored. Two major object properties are considered, namely, texture density which determines the rate of edge transitions for rotations in depth, i.e., the number of texture elements that pass an object's boundary per unit of time, and object size which determines the tangential linear velocities and 2D image velocities of texture elements for a given angular velocity. Results of experiments show that edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities had an impact on perceived angular velocity; this bias was associated with 2D image velocity rather than 3D tangential velocity. Despite these biases judgements were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter appeared to be good for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

Angular Acceleration without Torque?

ERIC Educational Resources Information Center

Kaufman, Richard D.

2012-01-01

Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

Tunable orbital angular momentum in high-harmonic generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gauthier, David; Ribič, P. Rebernik; Adhikary, G.

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light–matter interactions,more » and the disentanglement and independent control of the intrinsic and extrinsic components of the photon’s angular momentum at short-wavelengths. Finally, the methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.« less

Tunable orbital angular momentum in high-harmonic generation

DOE PAGES

Gauthier, David; Ribič, P. Rebernik; Adhikary, G.; ...

2017-04-05

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light–matter interactions,more » and the disentanglement and independent control of the intrinsic and extrinsic components of the photon’s angular momentum at short-wavelengths. Finally, the methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.« less

Tunable orbital angular momentum in high-harmonic generation

PubMed Central

Gauthier, D.; Ribič, P. Rebernik; Adhikary, G.; Camper, A.; Chappuis, C.; Cucini, R.; DiMauro, L. F.; Dovillaire, G.; Frassetto, F.; Géneaux, R.; Miotti, P.; Poletto, L.; Ressel, B.; Spezzani, C.; Stupar, M.; Ruchon, T.; De Ninno, G.

2017-01-01

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light–matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon's angular momentum at short-wavelengths. The methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms. PMID:28378741

Photonic polarization gears for ultra-sensitive angular measurements

PubMed Central

D'Ambrosio, Vincenzo; Spagnolo, Nicolò; Del Re, Lorenzo; Slussarenko, Sergei; Li, Ying; Kwek, Leong Chuan; Marrucci, Lorenzo; Walborn, Stephen P.; Aolita, Leandro; Sciarrino, Fabio

2013-01-01

Quantum metrology bears a great promise in enhancing measurement precision, but is unlikely to become practical in the near future. Its concepts can nevertheless inspire classical or hybrid methods of immediate value. Here we demonstrate NOON-like photonic states of m quanta of angular momentum up to m=100, in a setup that acts as a ‘photonic gear’, converting, for each photon, a mechanical rotation of an angle θ into an amplified rotation of the optical polarization by mθ, corresponding to a ‘super-resolving’ Malus’ law. We show that this effect leads to single-photon angular measurements with the same precision of polarization-only quantum strategies with m photons, but robust to photon losses. Moreover, we combine the gear effect with the quantum enhancement due to entanglement, thus exploiting the advantages of both approaches. The high ‘gear ratio’ m boosts the current state of the art of optical non-contact angular measurements by almost two orders of magnitude. PMID:24045270

Angular correlation function of 1.5 million luminous red galaxies: clustering evolution and a search for baryon acoustic oscillations

NASA Astrophysics Data System (ADS)

Sawangwit, U.; Shanks, T.; Abdalla, F. B.; Cannon, R. D.; Croom, S. M.; Edge, A. C.; Ross, Nicholas P.; Wake, D. A.

2011-10-01

We present the angular correlation function measured from photometric samples comprising 1562 800 luminous red galaxies (LRGs). Three LRG samples were extracted from the Sloan Digital Sky Survey (SDSS) imaging data, based on colour-cut selections at redshifts, z≈ 0.35, 0.55 and 0.7 as calibrated by the spectroscopic surveys, SDSS-LRG, 2dF-SDSS LRG and QSO (quasi-stellar object) (2SLAQ) and the AAΩ-LRG survey. The galaxy samples cover ≈7600 deg2 of sky, probing a total cosmic volume of ≈5.5 h-3 Gpc3. The small- and intermediate-scale correlation functions generally show significant deviations from a single power-law fit with a well-detected break at ≈1 h-1 Mpc, consistent with the transition scale between the one- and two-halo terms in halo occupation models. For galaxy separations 1-20 h-1 Mpc and at fixed luminosity, we see virtually no evolution of the clustering with redshift and the data are consistent with a simple high peaks biasing model where the comoving LRG space density is constant with z. At fixed z, the LRG clustering amplitude increases with luminosity in accordance with the simple high peaks model, with a typical LRG dark matter halo mass 1013-1014 h-1 M⊙. For r < 1 h-1 Mpc, the evolution is slightly faster and the clustering decreases towards high redshift consistent with a virialized clustering model. However, assuming the halo occupation distribution (HOD) and Λ cold dark matter (ΛCDM) halo merger frameworks, ˜2-3 per cent/Gyr of the LRGs are required to merge in order to explain the small scales clustering evolution, consistent with previous results. At large scales, our result shows good agreement with the SDSS-LRG result of Eisenstein et al. but we find an apparent excess clustering signal beyond the baryon acoustic oscillations (BAO) scale. Angular power spectrum analyses of similar LRG samples also detect a similar apparent large-scale clustering excess but more data are required to check for this feature in independent galaxy

Physical angular momentum separation for QED

NASA Astrophysics Data System (ADS)

Sun, Weimin

2017-04-01

We study the non-uniqueness problem of the gauge-invariant angular momentum separation for the case of QED, which stems from the recent controversy concerning the proper definitions of the orbital angular momentum and spin operator of the individual parts of a gauge field system. For the free quantum electrodynamics without matter, we show that the basic requirement of Euclidean symmetry selects a unique physical angular momentum separation scheme from the multitude of the possible angular momentum separation schemes constructed using the various gauge-invariant extensions (GIEs). Based on these results, we propose a set of natural angular momentum separation schemes for the case of interacting QED by invoking the formalism of asymptotic fields. Some perspectives on such a problem for the case of QCD are briefly discussed.

Fast angular synchronization for phase retrieval via incomplete information

NASA Astrophysics Data System (ADS)

Viswanathan, Aditya; Iwen, Mark

2015-08-01

We consider the problem of recovering the phase of an unknown vector, x ∈ ℂd, given (normalized) phase difference measurements of the form xjxk*/|xjxk*|, j,k ∈ {1,...,d}, and where xj* denotes the complex conjugate of xj. This problem is sometimes referred to as the angular synchronization problem. This paper analyzes a linear-time-in-d eigenvector-based angular synchronization algorithm and studies its theoretical and numerical performance when applied to a particular class of highly incomplete and possibly noisy phase difference measurements. Theoretical results are provided for perfect (noiseless) measurements, while numerical simulations demonstrate the robustness of the method to measurement noise. Finally, we show that this angular synchronization problem and the specific form of incomplete phase difference measurements considered arise in the phase retrieval problem - where we recover an unknown complex vector from phaseless (or magnitude) measurements.

Arbitrary spin-to-orbital angular momentum conversion of light.

PubMed

Devlin, Robert C; Ambrosio, Antonio; Rubin, Noah A; Mueller, J P Balthasar; Capasso, Federico

2017-11-17

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements-SAM-to-orbital angular momentum (OAM) converters-are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication. Copyright © 2017, American Association for the Advancement of Science.

Drell-Yan Angular Distributions at the E906 SeaQuest Experiment

NASA Astrophysics Data System (ADS)

Kleinjan, David

2016-09-01

Measurement of Drell-Yan angular distributions in the Collins-Soper frame provide a unique study of QCD. Previous experimental results showed a violation of the Lam-Tung relation (1 - λ ≠ 2 ν). This violation could be described by a range of non-perturbative effects, including the naive T-odd Boer-Mulders TMD, which describes spin-momentum correlations in the nucleon. Presently, E906/SeaQuest experiment at Fermilab can measure Drell-Yan dimuon pairs produced from a 120 GeV unpolarized proton beam directed on various nuclear targets. The Drell-Yan angular distributions will be measured at higher-x than previous experiments, further disentangling the role the Boer-Mulders TMD and other non-perturbative effects play in the structure of the nucleon. SeaQuest.

Angular shear plate

DOEpatents

Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

2009-07-14

One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

Effects of ultrashort laser pulses on angular distributions of photoionization spectra.

PubMed

Ooi, C H Raymond; Ho, W L; Bandrauk, A D

2017-07-27

We study the photoelectron spectra by intense laser pulses with arbitrary time dependence and phase within the Keldysh framework. An efficient semianalytical approach using analytical transition matrix elements for hydrogenic atoms in any initial state enables efficient and accurate computation of the photoionization probability at any observation point without saddle point approximation, providing comprehensive three dimensional photoelectron angular distribution for linear and elliptical polarizations, that reveal the intricate features and provide insights on the photoionization characteristics such as angular dispersions, shift and splitting of photoelectron peaks from the tunneling or above threshold ionization(ATI) regime to non-adiabatic(intermediate) and multiphoton ionization(MPI) regimes. This facilitates the study of the effects of various laser pulse parameters on the photoelectron spectra and their angular distributions. The photoelectron peaks occur at multiples of 2ħω for linear polarization while  odd-ordered peaks are suppressed in the direction perpendicular to the electric field. Short pulses create splitting and angular dispersion where the peaks are strongly correlated to the angles. For MPI and elliptical polarization with shorter pulses the peaks split into doublets and the first peak vanishes. The carrier envelope phase(CEP) significantly affects the ATI spectra while the Stark effect shifts the spectra of intermediate regime to higher energies due to interference.

Image correlation method for DNA sequence alignment.

PubMed

Curilem Saldías, Millaray; Villarroel Sassarini, Felipe; Muñoz Poblete, Carlos; Vargas Vásquez, Asticio; Maureira Butler, Iván

2012-01-01

The complexity of searches and the volume of genomic data make sequence alignment one of bioinformatics most active research areas. New alignment approaches have incorporated digital signal processing techniques. Among these, correlation methods are highly sensitive. This paper proposes a novel sequence alignment method based on 2-dimensional images, where each nucleic acid base is represented as a fixed gray intensity pixel. Query and known database sequences are coded to their pixel representation and sequence alignment is handled as object recognition in a scene problem. Query and database become object and scene, respectively. An image correlation process is carried out in order to search for the best match between them. Given that this procedure can be implemented in an optical correlator, the correlation could eventually be accomplished at light speed. This paper shows an initial research stage where results were "digitally" obtained by simulating an optical correlation of DNA sequences represented as images. A total of 303 queries (variable lengths from 50 to 4500 base pairs) and 100 scenes represented by 100 x 100 images each (in total, one million base pair database) were considered for the image correlation analysis. The results showed that correlations reached very high sensitivity (99.01%), specificity (98.99%) and outperformed BLAST when mutation numbers increased. However, digital correlation processes were hundred times slower than BLAST. We are currently starting an initiative to evaluate the correlation speed process of a real experimental optical correlator. By doing this, we expect to fully exploit optical correlation light properties. As the optical correlator works jointly with the computer, digital algorithms should also be optimized. The results presented in this paper are encouraging and support the study of image correlation methods on sequence alignment.

Do isokinetic angular velocity and contraction types affect the predictors of different anaerobic power tests?

PubMed

Yapici, Aysegul; Findikoglu, Gulin; Dundar, Ugur

2016-04-01

The purpose of this study was to investigate the most important predictor isokinetic muscle strength determined by different angular velocities and contraction types (i.e. concentric and eccentric) for selected anaerobic power tests in volleyball players. Twenty male and ten female amateur volleyball players participated in this study. Selected anaerobic power tests included Wingate Anaerobic Test (WAnT), squat jump (SJ) and countermovement jump (CMJ). Peak torque values were obtained at 60, 120, 240˚/s for concentric contraction of quadriceps (Qconc) and Hamstring (Hconc) and at 60˚/s for eccentric contraction of quadriceps (Qecc) and Hconc. Moderate to good correlations (r:0.409 to r:0.887) were found between anaerobic tests and isokinetic data including peak torque and total work of both Hconc and Qconc at 60, 120, 240°/s and Qecc at 60°/s (P<0.05). Qconc measured at each of 60, 120, 240°/s was found to be the only significant predictor for anaerobic tests in linear regression models (P<0.05). Correlation coefficient s for Qconc increased with increasing velocity for each of the anaerobic tests. Correlation coefficient of Qconc was highest for CMJ followed by SJ and WAnT at the same angular velocity. As a distinctive feature, both Qecc and Hconc at 60˚/s were significantly predictors for CMJ and SJ. Qconc peak torque was the single significant predictor for WAnT, SJ and CMJ and strength of the relation increases with increasing angular velocity. However, both Qecc and Hconc were significant indicators for CMJ and SJ. Training with higher isokinetic angular velocities and with eccentric contraction is desirable in a training program that has a goal of improving anaerobic performance in volleyball players.

Ground simulation of wide frequency band angular vibration for Lander's optic sensors

NASA Astrophysics Data System (ADS)

Xing, Zhigang; Xiang, Jianwei; Zheng, Gangtie

2017-11-01

To guide a lander of Moon or Mars exploration spacecraft during the stage of descent onto a desired place, optic sensors have been chosen to take the task, which include optic cameras and laser distance meters. However, such optic sensors are sensitive to vibrations, especially angular vibrations, from the lander. To reduce the risk of abnormal function and ensure the performance of optic sensors, ground simulations are necessary. More importantly, the simulations can be used as a method for examining the sensor performance and finding possible improvement on the sensor design. In the present paper, we proposed an angular vibration simulation method during the landing. This simulation method has been realized into product and applied to optic sensor tests for the moon lander. This simulator can generate random angular vibration in a frequency range from 0 to 2000Hz, the control precision is +/-1dB, and the linear translational speed can be set to the required descent speed. The operation and data processing methods of this developed simulator are the same as a normal shake table. The analysis and design methods are studied in the present paper, and test results are also provided.

Angular trapping of anisometric nano-objects in a fluid.

PubMed

Celebrano, Michele; Rosman, Christina; Sönnichsen, Carsten; Krishnan, Madhavi

2012-11-14

We demonstrate the ability to trap, levitate, and orient single anisometric nanoscale objects with high angular precision in a fluid. An electrostatic fluidic trap confines a spherical object at a spatial location defined by the minimum of the electrostatic system free energy. For an anisometric object and a potential well lacking angular symmetry, the system free energy can further strongly depend on the object's orientation in the trap. Engineering the morphology of the trap thus enables precise spatial and angular confinement of a single levitating nano-object, and the process can be massively parallelized. Since the physics of the trap depends strongly on the surface charge of the object, the method is insensitive to the object's dielectric function. Furthermore, levitation of the assembled objects renders them amenable to individual manipulation using externally applied optical, electrical, or hydrodynamic fields, raising prospects for reconfigurable chip-based nano-object assemblies.

Non-Colinearity of Angular Velocity and Angular Momentum

ERIC Educational Resources Information Center

Burr, A. F.

1974-01-01

Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

Magnetic resonance imaging volume of the angular gyri predicts financial skill deficits in people with amnestic mild cognitive impairment.

PubMed

Griffith, H Randall; Stewart, Christopher C; Stoeckel, Luke E; Okonkwo, Ozioma C; den Hollander, Jan A; Martin, Roy C; Belue, Katherine; Copeland, Jacquelynn N; Harrell, Lindy E; Brockington, John C; Clark, David G; Marson, Daniel C

2010-02-01

To better understand how brain atrophy in amnestic mild cognitive impairment (MCI) as measured using magnetic resonance imaging (MRI) volumetrics could affect instrumental activities of daily living (IADLs) such as financial abilities. Controlled, matched-sample, cross-sectional analysis regressing MRI volumetrics with financial performance measures. University medical and research center. Thirty-eight people with MCI and 28 older adult controls. MRI volumetric measurement of the hippocampi, angular gyri, precunei, and medial frontal lobes. Participants also completed neuropsychological tests and the Financial Capacity Instrument (FCI). Correlations were performed between FCI scores and MRI volumes in the group with MCI. People with MCI performed significantly below controls on the FCI and had significantly smaller hippocampi. Among people with MCI, performance on the FCI was moderately correlated with angular gyri and precunei volumes. Regression models demonstrated that angular gyrus volumes were predictive of FCI scores. Tests of mediation showed that measures of arithmetic and possibly attention partially mediated the relationship between angular gyrus volume and FCI score. Impaired financial abilities in amnestic MCI correspond with volume of the angular gyri as mediated by arithmetic knowledge. The findings suggest that early neuropathology within the lateral parietal region in MCI leads to a breakdown of cognitive abilities that affect everyday financial skills. The findings have implications for diagnosis and clinical care of people with MCI and AD.

Dynamic approach to description of entrance channel effects in angular distributions of fission fragments

NASA Astrophysics Data System (ADS)

Eremenko, D. O.; Drozdov, V. A.; Fotina, O. V.; Platonov, S. Yu.; Yuminov, O. A.

2016-07-01

Background: It is well known that the anomalous behavior of angular anisotropies of fission fragments at sub- and near-barrier energies is associated with a memory of conditions in the entrance channel of the heavy-ion reactions, particularly, deformations and spins of colliding nuclei that determine the initial distributions for the components of the total angular momentum over the symmetry axis of the fissioning system and the beam axis. Purpose: We develop a new dynamic approach, which allows the description of the memory effects in the fission fragment angular distributions and provides new information on fusion and fission dynamics. Methods: The approach is based on the dynamic model of the fission fragment angular distributions which takes into account stochastic aspects of nuclear fission and thermal fluctuations for the tilting mode that is characterized by the projection of the total angular momentum onto the symmetry axis of the fissioning system. Another base of our approach is the quantum mechanical method to calculate the initial distributions over the components of the total angular momentum of the nuclear system immediately following complete fusion. Results: A method is suggested for calculating the initial distributions of the total angular momentum projection onto the symmetry axis for the nuclear systems formed in the reactions of complete fusion of deformed nuclei with spins. The angular distributions of fission fragments for the 16O+232Th,12C+235,236,238, and 13C+235U reactions have been analyzed within the dynamic approach over a range of sub- and above-barrier energies. The analysis allowed us to determine the relaxation time for the tilting mode and the fraction of fission events occurring in times not larger than the relaxation time for the tilting mode. Conclusions: It is shown that the memory effects play an important role in the formation of the angular distributions of fission fragments for the reactions induced by heavy ions. The

Active motion assisted by correlated stochastic torques.

PubMed

Weber, Christian; Radtke, Paul K; Schimansky-Geier, Lutz; Hänggi, Peter

2011-07-01

The stochastic dynamics of an active particle undergoing a constant speed and additionally driven by an overall fluctuating torque is investigated. The random torque forces are expressed by a stochastic differential equation for the angular dynamics of the particle determining the orientation of motion. In addition to a constant torque, the particle is supplemented by random torques, which are modeled as an Ornstein-Uhlenbeck process with given correlation time τ(c). These nonvanishing correlations cause a persistence of the particles' trajectories and a change of the effective spatial diffusion coefficient. We discuss the mean square displacement as a function of the correlation time and the noise intensity and detect a nonmonotonic dependence of the effective diffusion coefficient with respect to both correlation time and noise strength. A maximal diffusion behavior is obtained if the correlated angular noise straightens the curved trajectories, interrupted by small pirouettes, whereby the correlated noise amplifies a straightening of the curved trajectories caused by the constant torque.

Angular dependence of primordial trispectra and CMB spectral distortions

NASA Astrophysics Data System (ADS)

Shiraishi, Maresuke; Bartolo, Nicola; Liguori, Michele

2016-10-01

Under the presence of anisotropic sources in the inflationary era, the trispectrum of the primordial curvature perturbation has a very specific angular dependence between each wavevector that is distinguishable from the one encountered when only scalar fields are present, characterized by an angular dependence described by Legendre polynomials. We examine the imprints left by curvature trispectra on the TTμ bispectrum, generated by the correlation between temperature anisotropies (T) and chemical potential spectral distortions (μ) of the Cosmic Microwave Background (CMB). Due to the angular dependence of the primordial signal, the corresponding TTμ bispectrum strongly differs in shape from TTμ sourced by the usual gNL or τNL local trispectra, enabling us to obtain an unbiased estimation. From a Fisher matrix analysis, we find that, in a cosmic-variance-limited (CVL) survey of TTμ, a minimum detectable value of the quadrupolar Legendre coefficient is d2 ~ 0.01, which is 4 orders of magnitude better than the best value attainable from the TTTT CMB trispectrum. In the case of an anisotropic inflationary model with a f(phi)F2 interaction (coupling the inflaton field phi with a vector kinetic term F2), the size of the curvature trispectrum is related to that of quadrupolar power spectrum asymmetry, g*. In this case, a CVL measurement of TTμ makes it possible to measure g* down to 10-3.

Intrinsic Angular Momentum of Light.

ERIC Educational Resources Information Center

Santarelli, Vincent

1979-01-01

Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

Low-energy measurements of electron-photon angular correlation in electron-impact excitation of the 2/sup 1/P state of helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steph, N.C.; Golden, D.E.

1983-03-01

Electron-photon angular correlations between electrons which have excited the 2/sup 1/P state of He and photons from the 2/sup 1/P..-->..1/sup 1/S transition have been studied for 27-, 30-, 35-, and 40-eV incident electrons. Values of lambda and Vertical BarchiVertical Bar obtained from these measurements are compared to values obtained in distorted-wave and R-matrix calculations. The values of lambda and Vertical BarchiVertical Bar have been combined to examine the behavior of Vertical BarO/sub 1//sub -//sup colvertical-bar/ (lambda(1-lambda)sinVertical BarchiVertical Bar), the nonvanishing component of orientation. At 27 eV, a substantial decrease was observed in the values of lambda and Vertical BarO/sub 1//submore » -//sup colvertical-bar/, compared with their values for E> or =30 eV.« less

A Study of Airplane Maneuvers with Special Reference to Angular Velocities

NASA Technical Reports Server (NTRS)

Reid, J E

1923-01-01

This investigation was undertaken by the National Advisory Committee for Aeronautics for the purpose of increasing our knowledge on the behavior of the airplane during various maneuvers and to obtain values of the maximum angular velocities and accelerations in flight. The method consisted in flying a JN4H airplane through various maneuvers while records were being taken of the control position, the air speed, the angular velocity and the acceleration along the Z axis. The results showed that the maximum angular velocity about the X axis of radians per second in a barrel roll. The maximum angular acceleration about the X axis of -2.10 radians per (second) to the 2nd power occurred in a spin, while the maximum about the Y axis was 1.40 radians per (second) to the 2nd power when pulling suddenly out of a dive. These results have direct application to the design of airplane parts, such as propeller shaft and instruments.

An investigation of angular stiffness and damping coefficients of an axial spline coupling in high-speed rotating machinery

NASA Technical Reports Server (NTRS)

Ku, C.-P. Roger; Walton, James F., Jr.; Lund, Jorgen W.

1994-01-01

This paper provided an opportunity to quantify the angular stiffness and equivalent viscous damping coefficients of an axial spline coupling used in high-speed turbomachinery. A unique test methodology and data reduction procedures were developed. The bending moments and angular deflections transmitted across an axial spline coupling were measured while a nonrotating shaft was excited by an external shaker. A rotor dynamics computer program was used to simulate the test conditions and to correlate the angular stiffness and damping coefficients. In addition, sensitivity analyses were performed to show that the accuracy of the dynamic coefficients do not rely on the accuracy of the data reduction procedures.

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks

NASA Astrophysics Data System (ADS)

Gul, M. Shahzeb Khan; Gunturk, Bahadir K.

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks.

PubMed

Gul, M Shahzeb Khan; Gunturk, Bahadir K

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

Optimal simulations of ultrasonic fields produced by large thermal therapy arrays using the angular spectrum approach

PubMed Central

Zeng, Xiaozheng; McGough, Robert J.

2009-01-01

The angular spectrum approach is evaluated for the simulation of focused ultrasound fields produced by large thermal therapy arrays. For an input pressure or normal particle velocity distribution in a plane, the angular spectrum approach rapidly computes the output pressure field in a three dimensional volume. To determine the optimal combination of simulation parameters for angular spectrum calculations, the effect of the size, location, and the numerical accuracy of the input plane on the computed output pressure is evaluated. Simulation results demonstrate that angular spectrum calculations performed with an input pressure plane are more accurate than calculations with an input velocity plane. Results also indicate that when the input pressure plane is slightly larger than the array aperture and is located approximately one wavelength from the array, angular spectrum simulations have very small numerical errors for two dimensional planar arrays. Furthermore, the root mean squared error from angular spectrum simulations asymptotically approaches a nonzero lower limit as the error in the input plane decreases. Overall, the angular spectrum approach is an accurate and robust method for thermal therapy simulations of large ultrasound phased arrays when the input pressure plane is computed with the fast nearfield method and an optimal combination of input parameters. PMID:19425640

Noise and analyzer-crystal angular position analysis for analyzer-based phase-contrast imaging

NASA Astrophysics Data System (ADS)

Majidi, Keivan; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

2014-04-01

The analyzer-based phase-contrast x-ray imaging (ABI) method is emerging as a potential alternative to conventional radiography. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that images are calculated from raw data). ABI can simultaneously generate a number of planar parametric images containing information about absorption, refraction, and scattering properties of an object. These images are estimated from raw data acquired by measuring (sampling) the angular intensity profile of the x-ray beam passed through the object at different angular positions of the analyzer crystal. The noise in the estimated ABI parametric images depends upon imaging conditions like the source intensity (flux), measurements angular positions, object properties, and the estimation method. In this paper, we use the Cramér-Rao lower bound (CRLB) to quantify the noise properties in parametric images and to investigate the effect of source intensity, different analyzer-crystal angular positions and object properties on this bound, assuming a fixed radiation dose delivered to an object. The CRLB is the minimum bound for the variance of an unbiased estimator and defines the best noise performance that one can obtain regardless of which estimation method is used to estimate ABI parametric images. The main result of this paper is that the variance (hence the noise) in parametric images is directly proportional to the source intensity and only a limited number of analyzer-crystal angular measurements (eleven for uniform and three for optimal non-uniform) are required to get the best parametric images. The following angular measurements only spread the total dose to the measurements without improving or worsening CRLB, but the added measurements may improve parametric images by reducing estimation bias. Next, using CRLB we evaluate the multiple-image radiography, diffraction enhanced imaging and scatter diffraction enhanced imaging estimation techniques

Noise and Analyzer-Crystal Angular Position Analysis for Analyzer-Based Phase-Contrast Imaging

PubMed Central

Majidi, Keivan; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

2014-01-01

The analyzer-based phase-contrast X-ray imaging (ABI) method is emerging as a potential alternative to conventional radiography. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that images are calculated from raw data). ABI can simultaneously generate a number of planar parametric images containing information about absorption, refraction, and scattering properties of an object. These images are estimated from raw data acquired by measuring (sampling) the angular intensity profile (AIP) of the X-ray beam passed through the object at different angular positions of the analyzer crystal. The noise in the estimated ABI parametric images depends upon imaging conditions like the source intensity (flux), measurements angular positions, object properties, and the estimation method. In this paper, we use the Cramér-Rao lower bound (CRLB) to quantify the noise properties in parametric images and to investigate the effect of source intensity, different analyzer-crystal angular positions and object properties on this bound, assuming a fixed radiation dose delivered to an object. The CRLB is the minimum bound for the variance of an unbiased estimator and defines the best noise performance that one can obtain regardless of which estimation method is used to estimate ABI parametric images. The main result of this manuscript is that the variance (hence the noise) in parametric images is directly proportional to the source intensity and only a limited number of analyzer-crystal angular measurements (eleven for uniform and three for optimal non-uniform) are required to get the best parametric images. The following angular measurements only spread the total dose to the measurements without improving or worsening CRLB, but the added measurements may improve parametric images by reducing estimation bias. Next, using CRLB we evaluate the Multiple-Image Radiography (MIR), Diffraction Enhanced Imaging (DEI) and Scatter Diffraction Enhanced Imaging (S

Measuring correlations in non-separable vector beams using projective measurements

NASA Astrophysics Data System (ADS)

Subramanian, Keerthan; Viswanathan, Nirmal K.

2017-09-01

Doubts regarding the completeness of quantum mechanics as raised by Einstein, Podolsky and Rosen(EPR) have predominantly been resolved by resorting to a measurement of correlations between entangled photons which clearly demonstrate violation of Bell's inequality. This article is an attempt to reconcile incompatibility of hidden variable theories with reality by demonstrating experimentally a violation of Bell's inequality in locally correlated systems whose two degrees of freedom, the spin and orbital angular momentum, are maximally correlated. To this end we propose and demonstrate a linear, achromatic modified Sagnac interferometer to project orbital angular momentum states which we combine with spin projections to measure correlations.

Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer.

PubMed

Liu, Xiaokun; Yao, Yu; Ma, Kemao; Zhao, Hui; He, Fenghua

2016-04-14

A gyrowheel (GW) is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS) as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO) with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper.

Angular Baryon Acoustic Oscillation measure at z=2.225 from the SDSS quasar survey

NASA Astrophysics Data System (ADS)

de Carvalho, E.; Bernui, A.; Carvalho, G. C.; Novaes, C. P.; Xavier, H. S.

2018-04-01

Following a quasi model-independent approach we measure the transversal BAO mode at high redshift using the two-point angular correlation function (2PACF). The analyses done here are only possible now with the quasar catalogue from the twelfth data release (DR12Q) from the Sloan Digital Sky Survey, because it is spatially dense enough to allow the measurement of the angular BAO signature with moderate statistical significance and acceptable precision. Our analyses with quasars in the redshift interval z in [2.20,2.25] produce the angular BAO scale θBAO = 1.77° ± 0.31° with a statistical significance of 2.12 σ (i.e., 97% confidence level), calculated through a likelihood analysis performed using the theoretical covariance matrix sourced by the analytical power spectra expected in the ΛCDM concordance model. Additionally, we show that the BAO signal is robust—although with less statistical significance—under diverse bin-size choices and under small displacements of the quasars' angular coordinates. Finally, we also performed cosmological parameter analyses comparing the θBAO predictions for wCDM and w(a)CDM models with angular BAO data available in the literature, including the measurement obtained here, jointly with CMB data. The constraints on the parameters ΩM, w0 and wa are in excellent agreement with the ΛCDM concordance model.

Quantification of Shape, Angularity, and Surface texture of Base Course Materials

DOT National Transportation Integrated Search

1998-01-01

A state-of-the-art review was conducted to determine existing test methods for characterizing the shape, angularity, and surface texture of coarse aggregates. The review found direct methods used by geologists to determine these characteristics. Thes...

Satellite angular velocity estimation based on star images and optical flow techniques.

PubMed

Fasano, Giancarmine; Rufino, Giancarlo; Accardo, Domenico; Grassi, Michele

2013-09-25

An optical flow-based technique is proposed to estimate spacecraft angular velocity based on sequences of star-field images. It does not require star identification and can be thus used to also deliver angular rate information when attitude determination is not possible, as during platform de tumbling or slewing. Region-based optical flow calculation is carried out on successive star images preprocessed to remove background. Sensor calibration parameters, Poisson equation, and a least-squares method are then used to estimate the angular velocity vector components in the sensor rotating frame. A theoretical error budget is developed to estimate the expected angular rate accuracy as a function of camera parameters and star distribution in the field of view. The effectiveness of the proposed technique is tested by using star field scenes generated by a hardware-in-the-loop testing facility and acquired by a commercial-off-the shelf camera sensor. Simulated cases comprise rotations at different rates. Experimental results are presented which are consistent with theoretical estimates. In particular, very accurate angular velocity estimates are generated at lower slew rates, while in all cases the achievable accuracy in the estimation of the angular velocity component along boresight is about one order of magnitude worse than the other two components.

Satellite Angular Velocity Estimation Based on Star Images and Optical Flow Techniques

PubMed Central

Fasano, Giancarmine; Rufino, Giancarlo; Accardo, Domenico; Grassi, Michele

2013-01-01

An optical flow-based technique is proposed to estimate spacecraft angular velocity based on sequences of star-field images. It does not require star identification and can be thus used to also deliver angular rate information when attitude determination is not possible, as during platform de tumbling or slewing. Region-based optical flow calculation is carried out on successive star images preprocessed to remove background. Sensor calibration parameters, Poisson equation, and a least-squares method are then used to estimate the angular velocity vector components in the sensor rotating frame. A theoretical error budget is developed to estimate the expected angular rate accuracy as a function of camera parameters and star distribution in the field of view. The effectiveness of the proposed technique is tested by using star field scenes generated by a hardware-in-the-loop testing facility and acquired by a commercial-off-the shelf camera sensor. Simulated cases comprise rotations at different rates. Experimental results are presented which are consistent with theoretical estimates. In particular, very accurate angular velocity estimates are generated at lower slew rates, while in all cases the achievable accuracy in the estimation of the angular velocity component along boresight is about one order of magnitude worse than the other two components. PMID:24072023

A Neural Circuit for Angular Velocity Computation

PubMed Central

Snider, Samuel B.; Yuste, Rafael; Packer, Adam M.

2010-01-01

In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly tunable wing steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuromechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob. PMID:21228902

A neural circuit for angular velocity computation.

PubMed

Snider, Samuel B; Yuste, Rafael; Packer, Adam M

2010-01-01

In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly tunable wing steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuromechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.

First Predictions of the Angular Power Spectrum of the Astrophysical Gravitational Wave Background

NASA Astrophysics Data System (ADS)

Cusin, Giulia; Dvorkin, Irina; Pitrou, Cyril; Uzan, Jean-Philippe

2018-06-01

We present the first predictions for the angular power spectrum of the astrophysical gravitational wave background constituted of the radiation emitted by all resolved and unresolved astrophysical sources. Its shape and amplitude depend on both the astrophysical properties on galactic scales and on cosmological properties. We show that the angular power spectrum behaves as Cℓ∝1 /ℓ on large scales and that relative fluctuations of the signal are of order 30% at 100 Hz. We also present the correlations of the astrophysical gravitational wave background with weak lensing and galaxy distribution. These numerical results pave the way to the study of a new observable at the crossroad between general relativity, astrophysics, and cosmology.

THE ANGULAR DISTRIBUTION OF POSITRONS IN $pi$$sup +$-$mu$$sup +$-e$sup +$ DECAY IN PROPANE (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alikhanyan, A.I.; Kirillov-Ugryumov, V.G.; Kotenko, L.P.

1958-01-01

In consideration of the wide use of propane bubble cameras, investigations were made of the angular distribution of electrons from pi /sup +/ -- mu /sup +/--e/sup +/ decay in propane to determine the possibility of using propane in angular correlation measurements of processes simlar to mu --e decay. The scheme of the experiment made with a bubble chamber of (7.2 x 6.5 x 16)cm/ dmensions bombarded by a 175-Mev pi -meson beam from a phasotron is described. (R.V.J.)

Studies of Point Defects and Defect Interactions in Metals Using Perturbed Gamma Gamma Angular Correlations

NASA Astrophysics Data System (ADS)

Shropshire, Steven Leslie

Point defects in plastically deformed Au, Pt, and Ni were studied with atomic-scale sensitivity using the perturbed gamma-gamma angular correlations (PAC) technique by monitoring formation and transformation of complexes of vacancy defects with very dilute ^{111}In/ ^{111}Cd solute probes. Three topics were investigated: (1) Production of vacancy defects during plastic deformation of Au was investigated to differentiate models of defect production. Concentrations of mono-, di-, and tri-vacancy species were measured in Au, and the ratio of mono- to di-vacancies was found to be independent of the amount of deformation. Results indicate that point defects are produced in correlated lattice locations, such as in "strings", as a consequence of dislocation interactions and not at random locations. (2) Hydrogen interactions with vacancy-solute complexes were studied in Pt. From thermal detrapping experiments, binding of hydrogen in complexes with mono-, di- and tri-vacancies was determined using a model for hydrogen diffusing in a medium with traps, with enthalpies all measured in the narrow range 0.23-0.28 eV, proving that the binding is insensitive to the precise structure of small vacancy clusters. Nuclear relaxation of the probe in a trivacancy complex in Pt was studied as a function of temperature, from which an activation energy of 0.34 eV was measured. This value is inconsistent with relaxation caused by diffusion or trapping of hydrogen, but explainable by dynamical hopping of the PAC probe atom in a cage of vacancies. (3) By observing transformations between vacancy-solute complexes induced by annihilation reactions, it was demonstrated that interstitials are produced during plastic deformation. The evolution of concentrations of the different vacancy complexes under an interstitial flux was measured and analyzed using a kinetic-rate model, from which interstitial capture cross-sections for the different vacancy complexes and the relative quantities of

Pitch-Plane Angular Displacement Perception During Helicopter Flight and Gondola Centrifugation.

PubMed

Tribukait, Arne; Bergsten, Eddie; Eiken, Ola

During hovering with a helicopter, an involuntary change in attitude (during brownout) results in reduced lifting force and a horizontal acceleration component. This movement pattern is difficult to perceive via the otolith organs. If the angular displacement occurs rapidly, it will, however, activate the semicircular canals. The major aim of this study was to establish to what extent pitch-plane angular displacements can be perceived based on canal information when there is no tilt stimulus to the otoliths. In a helicopter, 9 nonpilots (N) and 8 helicopter pilots (P) underwent 5-6 pitch-forward displacements (magnitude 14-33°, angular velocity 2-7° · s -1 ). In a swing-out gondola centrifuge, 9 N and 3 P were exposed to a similar canal-otolith conflict (acceleration, seated centripetally) with four displacements of 25° and two of 60°. The visually perceived eye level (VPEL) was continuously recorded using an adjustable luminous dot in darkness. For each helicopter dive and centrifuge run the gain was calculated as the ratio (VPEL deflection)/(displacement of helicopter or gondola). In the helicopter there was no difference between N (0.28 ± 0.13) and P (0.36 ± 0.22). In the centrifuge the gains were 0.34 ± 0.18° (25° displacements) and 0.30 ± 0.16° (60° displacements). Values obtained in the helicopter did not differ significantly from those in the centrifuge. There was a correlation between data obtained during the 25° and 60° displacements in the centrifuge. There was a pronounced underestimation of pitch angular displacements in a helicopter. The interindividual variability was considerable. Gains for perceived displacement were similar in helicopter and centrifuge. Tribukait A, Bergsten E, Eiken O. Pitch-plane angular displacement perception during helicopter flight and gondola centrifugation. Aerosp Med Hum Perform. 2016; 87(10):852-861.

High angular resolution at LBT

NASA Astrophysics Data System (ADS)

Conrad, A.; Arcidiacono, C.; Bertero, M.; Boccacci, P.; Davies, A. G.; Defrere, D.; de Kleer, K.; De Pater, I.; Hinz, P.; Hofmann, K. H.; La Camera, A.; Leisenring, J.; Kürster, M.; Rathbun, J. A.; Schertl, D.; Skemer, A.; Skrutskie, M.; Spencer, J. R.; Veillet, C.; Weigelt, G.; Woodward, C. E.

2015-12-01

High angular resolution from ground-based observatories stands as a key technology for advancing planetary science. In the window between the angular resolution achievable with 8-10 meter class telescopes, and the 23-to-40 meter giants of the future, LBT provides a glimpse of what the next generation of instruments providing higher angular resolution will provide. We present first ever resolved images of an Io eruption site taken from the ground, images of Io's Loki Patera taken with Fizeau imaging at the 22.8 meter LBT [Conrad, et al., AJ, 2015]. We will also present preliminary analysis of two data sets acquired during the 2015 opposition: L-band fringes at Kurdalagon and an occultation of Loki and Pele by Europa (see figure). The light curves from this occultation will yield an order of magnitude improvement in spatial resolution along the path of ingress and egress. We will conclude by providing an overview of the overall benefit of recent and future advances in angular resolution for planetary science.

Variations in atmospheric angular momentum

NASA Technical Reports Server (NTRS)

Rosen, R. D.; Salstein, D. A.

1981-01-01

Twice-daily values of the atmosphere's angular momentum about the polar axis during the five years from 1976 through 1980 are presented in graphs and a table. The compilation is based on a global data set, incorporating 90 percent of the mass of the atmosphere. The relationship between changes in the angular momentum of the atmosphere and changes in the length of day is described, as are the main sources of error in the data. The variability in angular momentum is revealed in a preliminary fashion by means of a spectral decomposition. The data presented should stimulate comparisons with other measures of the length of day and so provide a basis for greater understanding of Earth-atmosphere interactions.

Angular integrals in d dimensions

NASA Astrophysics Data System (ADS)

Somogyi, Gábor

2011-08-01

We discuss the evaluation of certain d-dimensional angular integrals which arise in perturbative field theory calculations. We find that the angular integral with n denominators can be computed in terms of a certain special function, the so-called H-function of several variables. We also present several illustrative examples of the general result and briefly consider some applications.

Improved Plane-Wave Ultrasound Beamforming by Incorporating Angular Weighting and Coherent Compounding in Fourier Domain.

PubMed

Chen, Chuan; Hendriks, Gijs A G M; van Sloun, Ruud J G; Hansen, Hendrik H G; de Korte, Chris L

2018-05-01

In this paper, a novel processing framework is introduced for Fourier-domain beamforming of plane-wave ultrasound data, which incorporates coherent compounding and angular weighting in the Fourier domain. Angular weighting implies spectral weighting by a 2-D steering-angle-dependent filtering template. The design of this filter is also optimized as part of this paper. Two widely used Fourier-domain plane-wave ultrasound beamforming methods, i.e., Lu's f-k and Stolt's f-k methods, were integrated in the framework. To enable coherent compounding in Fourier domain for the Stolt's f-k method, the original Stolt's f-k method was modified to achieve alignment of the spectra for different steering angles in k-space. The performance of the framework was compared for both methods with and without angular weighting using experimentally obtained data sets (phantom and in vivo), and data sets (phantom) provided by the IEEE IUS 2016 plane-wave beamforming challenge. The addition of angular weighting enhanced the image contrast while preserving image resolution. This resulted in images of equal quality as those obtained by conventionally used delay-and-sum (DAS) beamforming with apodization and coherent compounding. Given the lower computational load of the proposed framework compared to DAS, to our knowledge it can, therefore, be concluded that it outperforms commonly used beamforming methods such as Stolt's f-k, Lu's f-k, and DAS.

Fluidic angular velocity sensor

NASA Technical Reports Server (NTRS)

Berdahl, C. M. (Inventor)

1986-01-01

A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input is described. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

Synchrotron-radiation based perturbed angular correlations from 119Sn

NASA Astrophysics Data System (ADS)

Strohm, C.; Sergueev, I.; van Bürck, U.

2008-03-01

We report the observation of γ-γ-correlations from 119Sn using nuclear resonant scattering of synchrotron radiation, extending nuclear resonant spectroscopy with 119Sn to vanishing recoilless fractions and new applications. The 23.87 keV M1 (+E2) Ig:1/2→Ie:3/2 Mössbauer transition was excited from the ground state, and the time differential correlations between the incident and the scattered photons were recorded for different angles in the plane perpendicular to the incident beam. The experiments were performed on samples of tributyltin-fluoride, which has a very low Lamb-Mössbauer factor at ambient temperature. In the time spectra we observed quantum beats from the static perturbation through electric quadrupole interaction.

Nanosecond Dynamics at Protein Metal Sites: An Application of Perturbed Angular Correlation (PAC) of γ-Rays Spectroscopy.

PubMed

Chakraborty, Saumen; Pallada, Stavroula; Pedersen, Jeppe T; Jancso, Attila; Correia, Joao G; Hemmingsen, Lars

2017-09-19

Metalloproteins are essential to numerous reactions in nature, and constitute approximately one-third of all known proteins. Molecular dynamics of proteins has been elucidated with great success both by experimental and theoretical methods, revealing atomic level details of function involving the organic constituents on a broad spectrum of time scales. However, the characterization of dynamics at biomolecular metal sites on nanosecond time scales is scarce in the literature. The aqua ions of many biologically relevant metal ions exhibit exchange of water molecules on the nanosecond time scale or faster, often defining their reactivity in aqueous solution, and this is presumably also a relevant time scale for the making and breaking of coordination bonds between metal ions and ligands at protein metal sites. Ligand exchange dynamics is critical for a variety of elementary steps of reactions in metallobiochemistry, for example, association and dissociation of metal bound water, association of substrate and dissociation of product in the catalytic cycle of metalloenzymes, at regulatory metal sites which require binding and dissociation of metal ions, as well as in the transport of metal ions across cell membranes or between proteins involved in metal ion homeostasis. In Perturbed Angular Correlation of γ-rays (PAC) spectroscopy, the correlation in time and space of two γ-rays emitted successively in a nuclear decay is recorded, reflecting the hyperfine interactions of the PAC probe nucleus with the surroundings. This allows for characterization of molecular and electronic structure as well as nanosecond dynamics at the PAC probe binding site. Herein, selected examples describing the application of PAC spectroscopy in probing the dynamics at protein metal sites are presented, including (1) exchange of Cd 2+ bound water in de novo designed synthetic proteins, and the effect of remote mutations on metal site dynamics; (2) dynamics at the β-lactamase active site, where

The generalized formula for angular velocity vector of the moving coordinate system

NASA Astrophysics Data System (ADS)

Ermolin, Vladislav S.; Vlasova, Tatyana V.

2018-05-01

There are various ways for introducing the concept of the instantaneous angular velocity vector. In this paper we propose a method based on introducing of this concept by construction of the solution for the system of kinematic equations. These equations connect the function vectors defining the motion of the basis, and their derivatives. Necessary and sufficient conditions for the existence and uniqueness of the solution of this system are established. The instantaneous angular velocity vector is a solution of the algebraic system of equations. It is built explicitly. The derived formulas for the angular velocity vector generalize the earlier results, both for a basis of an affine oblique coordinate system and for an orthonormal basis.

Angular dependence of primordial trispectra and CMB spectral distortions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiraishi, Maresuke; Bartolo, Nicola; Liguori, Michele, E-mail: maresuke.shiraishi@ipmu.jp, E-mail: nicola.bartolo@pd.infn.it, E-mail: michele.liguori@pd.infn.it

2016-10-01

Under the presence of anisotropic sources in the inflationary era, the trispectrum of the primordial curvature perturbation has a very specific angular dependence between each wavevector that is distinguishable from the one encountered when only scalar fields are present, characterized by an angular dependence described by Legendre polynomials. We examine the imprints left by curvature trispectra on the TT μ bispectrum, generated by the correlation between temperature anisotropies (T) and chemical potential spectral distortions (μ) of the Cosmic Microwave Background (CMB). Due to the angular dependence of the primordial signal, the corresponding TT μ bispectrum strongly differs in shape frommore » TT μ sourced by the usual g {sub NL} or τ{sub NL} local trispectra, enabling us to obtain an unbiased estimation. From a Fisher matrix analysis, we find that, in a cosmic-variance-limited (CVL) survey of TT μ, a minimum detectable value of the quadrupolar Legendre coefficient is d {sub 2} ∼ 0.01, which is 4 orders of magnitude better than the best value attainable from the TTTT CMB trispectrum. In the case of an anisotropic inflationary model with a f (φ) F {sup 2} interaction (coupling the inflaton field φ with a vector kinetic term F {sup 2}), the size of the curvature trispectrum is related to that of quadrupolar power spectrum asymmetry, g {sub *}. In this case, a CVL measurement of TT μ makes it possible to measure g {sub *} down to 10{sup −3}.« less

Remote Sensing of Multiple Cloud Layer Heights Using Multi-Angular Measurements

NASA Technical Reports Server (NTRS)

Sinclair, Kenneth; Van Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John; Wasilewski, Andrzej; Mcgill, Matthew

2017-01-01

Cloud top height (CTH) affects the radiative properties of clouds. Improved CTH observations will allow for improved parameterizations in large-scale models and accurate information on CTH is also important when studying variations in freezing point and cloud microphysics. NASAs airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. For the determination of CTH, a set of consecutive nadir reflectances is selected and the cross-correlations between this set and co-located sets at other viewing angles are calculated for a range of assumed cloud top heights, yielding a correlation profile. Under the assumption that cloud reflectances are isotropic, local peaks in the correlation profile indicate cloud layers. This technique can be applied to every RSP footprint and we demonstrate that detection of multiple peaks in the correlation profile allow retrieval of heights of multiple cloud layers within single RSP footprints. This paper provides an in-depth description of the architecture and performance of the RSPs CTH retrieval technique using data obtained during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC(exp. 4)RS) campaign. RSP retrieved cloud heights are evaluated using collocated data from the Cloud Physics Lidar (CPL). The method's accuracy associated with the magnitude of correlation, optical thickness, cloud thickness and cloud height are explored. The technique is applied to measurements at a wavelength of 670 nm and 1880 nm and their combination. The 1880-nm band is virtually insensitive to the lower troposphere due to strong water vapor absorption.

Measuring average angular velocity with a smartphone magnetic field sensor

NASA Astrophysics Data System (ADS)

Pili, Unofre; Violanda, Renante

2018-02-01

The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper, we present a further alternative that is smartphone-based, making use of the real-time magnetic field (simply called B-field in what follows) data gathering capability of the B-field sensor of the smartphone device as the timer for measuring average rotational period and average angular velocity. The in-built B-field sensor in smartphones has already found a number of uses in undergraduate experimental physics. For instance, in elementary electrodynamics, it has been used to explore the well-known Bio-Savart law and in a measurement of the permeability of air.

The examinations of microorganisms by correlation optics method

NASA Astrophysics Data System (ADS)

Bilyi, Olexander I.

2004-06-01

In report described methods of correlation optics, which are based on the analysis of intensity changes of quasielastic light scattering by micro-organisms and allow the type of correlation function to obtain information about the size of dispersive particles. The principle of new optical method of verification is described. In this method the gauging of intensity of an indirect illumination is carried out by static spectroscopy and processing of observed data by a method of correlation spectroscopy. The given mode of gauging allows measuring allocation of micro-organisms in size interval of 0.1 - 10.0 microns. In the report results of examinations of cultures Pseudomonas aeruginosa, Escherichia coli, Micrococcus lutteus, Lamprocystis and Triocapsa bacteriachlorofil are considered.

Analysis and Compensation of Modulation Angular Rate Error Based on Missile-Borne Rotation Semi-Strapdown Inertial Navigation System

PubMed Central

Zhang, Jiayu; Li, Jie; Zhang, Xi; Che, Xiaorui; Huang, Yugang; Feng, Kaiqiang

2018-01-01

The Semi-Strapdown Inertial Navigation System (SSINS) provides a new solution to attitude measurement of a high-speed rotating missile. However, micro-electro-mechanical-systems (MEMS) inertial measurement unit (MIMU) outputs are corrupted by significant sensor errors. In order to improve the navigation precision, a rotation modulation technology method called Rotation Semi-Strapdown Inertial Navigation System (RSSINS) is introduced into SINS. In fact, the stability of the modulation angular rate is difficult to achieve in a high-speed rotation environment. The changing rotary angular rate has an impact on the inertial sensor error self-compensation. In this paper, the influence of modulation angular rate error, including acceleration-deceleration process, and instability of the angular rate on the navigation accuracy of RSSINS is deduced and the error characteristics of the reciprocating rotation scheme are analyzed. A new compensation method is proposed to remove or reduce sensor errors so as to make it possible to maintain high precision autonomous navigation performance by MIMU when there is no external aid. Experiments have been carried out to validate the performance of the method. In addition, the proposed method is applicable for modulation angular rate error compensation under various dynamic conditions. PMID:29734707

Analysis and Compensation of Modulation Angular Rate Error Based on Missile-Borne Rotation Semi-Strapdown Inertial Navigation System.

PubMed

Zhang, Jiayu; Li, Jie; Zhang, Xi; Che, Xiaorui; Huang, Yugang; Feng, Kaiqiang

2018-05-04

The Semi-Strapdown Inertial Navigation System (SSINS) provides a new solution to attitude measurement of a high-speed rotating missile. However, micro-electro-mechanical-systems (MEMS) inertial measurement unit (MIMU) outputs are corrupted by significant sensor errors. In order to improve the navigation precision, a rotation modulation technology method called Rotation Semi-Strapdown Inertial Navigation System (RSSINS) is introduced into SINS. In fact, the stability of the modulation angular rate is difficult to achieve in a high-speed rotation environment. The changing rotary angular rate has an impact on the inertial sensor error self-compensation. In this paper, the influence of modulation angular rate error, including acceleration-deceleration process, and instability of the angular rate on the navigation accuracy of RSSINS is deduced and the error characteristics of the reciprocating rotation scheme are analyzed. A new compensation method is proposed to remove or reduce sensor errors so as to make it possible to maintain high precision autonomous navigation performance by MIMU when there is no external aid. Experiments have been carried out to validate the performance of the method. In addition, the proposed method is applicable for modulation angular rate error compensation under various dynamic conditions.

Effects of melamine formaldehyde resin and CaCO3 diffuser-loaded encapsulation on correlated color temperature uniformity of phosphor-converted LEDs.

PubMed

Yang, Liang; Lv, Zhicheng; Jiaojiao, Yuan; Liu, Sheng

2013-08-01

Phosphor-free dispensing is the most widely used LED packaging method, but this method results in poor quality in angular CCT uniformity. This study proposes a diffuser-loaded encapsulation to solve the problem; the effects of melamine formaldehyde (MF) resin and CaCO3 loaded encapsulation on correlated color temperature (CCT) uniformity and luminous efficiency reduction of the phosphor-converted LEDs are investigated. Results reveal that MF resin loaded encapsulation has better light diffusion performance compared to MF resin loaded encapsulation at the same diffuser concentration, but CaCO3 loaded encapsulation has better luminous efficiency maintenance. The improvements in angular color uniformity for the LEDs emitting with MF resin and CaCO3 loaded encapsulation can be explained by the increase in photon scattering. The utility of this low cost and controllable mineral diffuser packaging method provides a practical approach for enhancing the angular color uniformity of LEDs. The diffuser mass ratio of 1% MF resin or 10% CaCO3 is the optimum condition to obtain low angular CCT variance and high luminous efficiency.

Magnetometer-only attitude and angular velocity filtering estimation for attitude changing spacecraft

NASA Astrophysics Data System (ADS)

Ma, Hongliang; Xu, Shijie

2014-09-01

This paper presents an improved real-time sequential filter (IRTSF) for magnetometer-only attitude and angular velocity estimation of spacecraft during its attitude changing (including fast and large angular attitude maneuver, rapidly spinning or uncontrolled tumble). In this new magnetometer-only attitude determination technique, both attitude dynamics equation and first time derivative of measured magnetic field vector are directly leaded into filtering equations based on the traditional single vector attitude determination method of gyroless and real-time sequential filter (RTSF) of magnetometer-only attitude estimation. The process noise model of IRTSF includes attitude kinematics and dynamics equations, and its measurement model consists of magnetic field vector and its first time derivative. The observability of IRTSF for small or large angular velocity changing spacecraft is evaluated by an improved Lie-Differentiation, and the degrees of observability of IRTSF for different initial estimation errors are analyzed by the condition number and a solved covariance matrix. Numerical simulation results indicate that: (1) the attitude and angular velocity of spacecraft can be estimated with sufficient accuracy using IRTSF from magnetometer-only data; (2) compared with that of RTSF, the estimation accuracies and observability degrees of attitude and angular velocity using IRTSF from magnetometer-only data are both improved; and (3) universality: the IRTSF of magnetometer-only attitude and angular velocity estimation is observable for any different initial state estimation error vector.

CONNECTING ANGULAR MOMENTUM AND GALACTIC DYNAMICS: THE COMPLEX INTERPLAY BETWEEN SPIN, MASS, AND MORPHOLOGY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teklu, Adelheid F.; Remus, Rhea-Silvia; Dolag, Klaus

The evolution and distribution of the angular momentum of dark matter (DM) halos have been discussed in several studies over the past decades. In particular, the idea arose that angular momentum conservation should allow us to infer the total angular momentum of the entire DM halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especially for disk galaxies. To test this idea and to understand the connection between the angular momentum of the DM halo and its galaxy, we use a state-of-the-art, hydrodynamical cosmological simulation taken from the set of Magneticummore » Pathfinder simulations. Thanks to the inclusion of the relevant physical processes, the improved underlying numerical methods, and high spatial resolution, we successfully produce populations of spheroidal and disk galaxies self-consistently. Thus, we are able to study the dependence of galactic properties on their morphology. We find that (1) the specific angular momentum of stars in disk and spheroidal galaxies as a function of their stellar mass compares well with observational results; (2) the specific angular momentum of the stars in disk galaxies is slightly smaller compared to the specific angular momentum of the cold gas, in good agreement with observations; (3) simulations including the baryonic component show a dichotomy in the specific stellar angular momentum distribution when splitting the galaxies according to their morphological type (this dichotomy can also be seen in the spin parameter, where disk galaxies populate halos with slightly larger spin compared to spheroidal galaxies); (4) disk galaxies preferentially populate halos in which the angular momentum vector of the DM component in the central part shows a better alignment to the angular momentum vector of the entire halo; and (5) the specific angular momentum of the cold gas in disk galaxies is approximately 40% smaller than the specific angular momentum of the total

Characterization of the Bell-Shaped Vibratory Angular Rate Gyro

PubMed Central

Liu, Ning; Su, Zhong; Li, Qing; Fu, MengYin; Liu, Hong; Fan, JunFang

2013-01-01

The bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a novel shell vibratory gyroscope, which is inspired by the Chinese traditional bell. It sensitizes angular velocity through the standing wave precession effect. The bell-shaped resonator is a core component of the BVG and looks like the millimeter-grade Chinese traditional bell, such as QianLong Bell and Yongle Bell. It is made of Ni43CrTi, which is a constant modulus alloy. The exciting element, control element and detection element are uniformly distributed and attached to the resonator, respectively. This work presents the design, analysis and experimentation on the BVG. It is most important to analyze the vibratory character of the bell-shaped resonator. The strain equation, internal force and the resonator's equilibrium differential equation are derived in the orthogonal curvilinear coordinate system. When the input angular velocity is existent on the sensitive axis, an analysis of the vibratory character is performed using the theory of thin shells. On this basis, the mode shape function and the simplified second order normal vibration mode dynamical equation are obtained. The coriolis coupling relationship about the primary mode and secondary mode is established. The methods of the signal processing and control loop are presented. Analyzing the impact resistance property of the bell-shaped resonator, which is compared with other shell resonators using the Finite Element Method, demonstrates that BVG has the advantage of a better impact resistance property. A reasonable means of installation and a prototypal gyro are designed. The gyroscopic effect of the BVG is characterized through experiments. Experimental results show that the BVG has not only the advantages of low cost, low power, long work life, high sensitivity, and so on, but, also, of a simple structure and a better impact resistance property for low and medium angular velocity measurements. PMID:23966183

Characterization of the bell-shaped vibratory angular rate gyro.

PubMed

Liu, Ning; Su, Zhong; Li, Qing; Fu, MengYin; Liu, Hong; Fan, JunFang

2013-08-07

The bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a novel shell vibratory gyroscope, which is inspired by the Chinese traditional bell. It sensitizes angular velocity through the standing wave precession effect. The bell-shaped resonator is a core component of the BVG and looks like the millimeter-grade Chinese traditional bell, such as QianLong Bell and Yongle Bell. It is made of Ni43CrTi, which is a constant modulus alloy. The exciting element, control element and detection element are uniformly distributed and attached to the resonator, respectively. This work presents the design, analysis and experimentation on the BVG. It is most important to analyze the vibratory character of the bell-shaped resonator. The strain equation, internal force and the resonator's equilibrium differential equation are derived in the orthogonal curvilinear coordinate system. When the input angular velocity is existent on the sensitive axis, an analysis of the vibratory character is performed using the theory of thin shells. On this basis, the mode shape function and the simplified second order normal vibration mode dynamical equation are obtained. The coriolis coupling relationship about the primary mode and secondary mode is established. The methods of the signal processing and control loop are presented. Analyzing the impact resistance property of the bell-shaped resonator, which is compared with other shell resonators using the Finite Element Method, demonstrates that BVG has the advantage of a better impact resistance property. A reasonable means of installation and a prototypal gyro are designed. The gyroscopic effect of the BVG is characterized through experiments. Experimental results show that the BVG has not only the advantages of low cost, low power, long work life, high sensitivity, and so on, but, also, of a simple structure and a better impact resistance property for low and medium angular velocity measurements.

Spin correlations in the {Lambda}{Lambda} and {Lambda}{Lambda}-bar systems generated in relativistic heavy-ion collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyuboshitz, V. L.; Lyuboshitz, V. V., E-mail: Valery.Lyuboshitz@jinr.r

2010-05-15

Spin correlations for the {Lambda}{Lambda} and {Lambda}{Lambda}-bar pairs, generated in relativistic heavy-ion collisions, and related angular correlations at the joint registration of hadronic decays of two hyperons, in which space parity is not conserved, are analyzed. The correlation tensor components can be derived from the double angular distribution of products of two decays by the method of 'moments'. The properties of the 'trace' of the correlation tensor (a sum of three diagonal components), determining the relative fractions of the triplet states and singlet state of respective pairs, are discussed. Spin correlations for two identical particles ({Lambda}{Lambda}) and two nonidentical particlesmore » ({Lambda}{Lambda}-bar) are considered from the viewpoint of the conventional model of one-particle sources. In the framework of this model, correlations vanish at sufficiently large relative momenta. However, under these conditions, in the case of two nonidentical particles ({Lambda}{Lambda}-bar) a noticeable role is played by two-particle annihilation (two-quark, two-gluon) sources, which lead to the difference of the correlation tensor from zero. In particular, such a situation may arise when the system passes through the 'mixed phase.'« less

Gas Accretion and Angular Momentum

NASA Astrophysics Data System (ADS)

Stewart, Kyle R.

In this chapter, we review the role of gas accretion to the acquisition of angular momentum, both in galaxies and in their gaseous halos. We begin by discussing angular momentum in dark matter halos, with a brief review of tidal torque theory and the importance of mergers, followed by a discussion of the canonical picture of galaxy formation within this framework, where halo gas is presumed to shock-eat to the virial temperature of the halo, following the same spin distribution as the dark matter halo before cooling to the center of the halo to form a galaxy there. In the context of recent observational evidence demonstrating the presence of high angular momentum gas in galaxy halos, we review recent cosmological hydrodynamic simulations that have begun to emphasize the role of "cold flow" accretion—anisotropic gas accretion along cosmic filaments that does not shock-heat before sinking to the central galaxy. We discuss the implications of these simulations, reviewing a number of recent developments in the literature, and suggest a revision to the canonical model as it relates to the expected angular momentum content of gaseous halos around galaxies.

Galaxy spin as a formation probe: the stellar-to-halo specific angular momentum relation

NASA Astrophysics Data System (ADS)

Posti, Lorenzo; Pezzulli, Gabriele; Fraternali, Filippo; Di Teodoro, Enrico M.

2018-03-01

We derive the stellar-to-halo specific angular momentum relation (SHSAMR) of galaxies at z = 0 by combining (i) the standard Λcold dark matter tidal torque theory, (ii) the observed relation between stellar mass and specific angular momentum (the Fall relation), and (iii) various determinations of the stellar-to-halo mass relation (SHMR). We find that the ratio fj = j*/jh of the specific angular momentum of stars to that of the dark matter (i) varies with mass as a double power law, (ii) always has a peak in the mass range explored and iii) is three to five times larger for spirals than for ellipticals. The results have some dependence on the adopted SHMR and we provide fitting formulae in each case. For any choice of the SHMR, the peak of fj occurs at the same mass where the stellar-to-halo mass ratio f* = M*/Mh has a maximum. This is mostly driven by the straightness and tightness of the Fall relation, which requires fj and f* to be correlated with each other roughly as f_j∝ f_\\ast ^{2/3}, as expected if the outer and more angular momentum rich parts of a halo failed to accrete on to the central galaxy and form stars (biased collapse). We also confirm that the difference in the angular momentum of spirals and ellipticals at a given mass is too large to be ascribed only to different spins of the parent dark-matter haloes (spin bias).

Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer

PubMed Central

Liu, Xiaokun; Yao, Yu; Ma, Kemao; Zhao, Hui; He, Fenghua

2016-01-01

A gyrowheel (GW) is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS) as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO) with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper. PMID:27089347

Angular circulation speed of tablets in a vibratory tablet coating pan.

PubMed

Kumar, Rahul; Wassgren, Carl

2013-03-01

In this work, a single tablet model and a discrete element method (DEM) computer simulation are developed to obtain the angular circulation speed of tablets in a vibratory tablet coating pan for range of vibration frequencies and amplitudes. The models identify three important dimensionless parameters that influence the speed of the tablets: the dimensionless amplitude ratio (a/R), the Froude number (aω2/g), and the tablet-wall friction coefficient, where a is the peak vibration amplitude at the drum center, ω is the vibration angular frequency, R is the drum radius, and g is the acceleration due to gravity. The models predict that the angular circulation speed of tablets increases with an increase in each of these parameters. The rate of increase in the angular circulation speed is observed to decrease for larger values of a/R. The angular circulation speed reaches an asymptote beyond a tablet-wall friction coefficient value of about 0.4. Furthermore, it is found that the Froude number should be greater than one for the tablets to start circulating. The angular circulation speed increases as Froude number increases but then does not change significantly at larger values of the Froude number. Period doubling, where the motion of the bed is repeated every two cycles, occurs at a Froude number larger than five. The single tablet model, although much simpler than the DEM model, is able to predict the maximum circulation speed (the limiting case for a large value of tablet-wall friction coefficient) as well as the transition to period doubling.

Round and angular kyphosis in paediatric patients.

PubMed

Miladi, L

2013-02-01

Structural kyphosis is a posterior convex deformity of the spine that may appear in childhood then worsen with growth, most notably during the pubertal growth spurt. The abnormal curvature may be smooth, defining round kyphosis, or may display a sharp angular pattern. Angular kyphosis is the more severe of the two forms. The main causes of round kyphosis are postural kyphosis and Scheuermann's disease. The spontaneous outcome is favourable, and round kyphosis is well tolerated in adulthood. The treatment relies on orthopaedic methods in the overwhelming majority of cases. Surgery is reserved for severe rigid kyphosis in older children and for kyphosis responsible for refractory pain or neurological deficits. Surgical treatment carries a non-negligible risk of neurological, gastrointestinal, mechanical, and septic complications, which should be explained clearly to the family. Advances in contemporary posterior instrumentation have considerably limited the indications for anterior approaches. Many conditions may cause angular kyphosis, whose greater severity is related to a greater potential for progression and neurological impairment. Clinical investigations are in order to identify the cause and to plan the surgical strategy. Early surgery may be indicated, via a combined anterior and posterior approach. Anterior strut grafting, anterior or posterior osteotomies, or even vertebral column resections may be necessary to correct a major deformity. Copyright © 2012. Published by Elsevier Masson SAS.

Angular dependence of the nanoDot OSL dosimeter

PubMed Central

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan; Followill, David S.; Ibbott, Geoffrey S.

2011-01-01

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight∕OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system.Methods: Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, as well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX.Results: When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found.Conclusions: A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions. PMID:21858992

Multiscale Capability in Rattlesnake using Contiguous Discontinuous Discretization of Self-Adjoint Angular Flux Equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Weixiong; Wang, Yaqi; DeHart, Mark D.

2016-09-01

In this report, we present a new upwinding scheme for the multiscale capability in Rattlesnake, the MOOSE based radiation transport application. Comparing with the initial implementation of multiscale utilizing Lagrange multipliers to impose strong continuity of angular flux on interface of in-between subdomains, this scheme does not require the particular domain partitioning. This upwinding scheme introduces discontinuity of angular flux and resembles the classic upwinding technique developed for solving first order transport equation using discontinuous finite element method (DFEM) on the subdomain interfaces. Because this scheme restores the causality of radiation streaming on the interfaces, significant accuracy improvement can bemore » observed with moderate increase of the degrees of freedom comparing with the continuous method over the entire solution domain. Hybrid SN-PN is implemented and tested with this upwinding scheme. Numerical results show that the angular smoothing required by Lagrange multiplier method is not necessary for the upwinding scheme.« less

Creating high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses

NASA Astrophysics Data System (ADS)

Xin, PeiPei; Cheng, Hong; Zhang, ShanShan; Wang, HanMu; Xu, ZiShan; Liu, HongPing

2018-04-01

We propose a method of producing high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses. The first positive-polarity optical half-cycle pulse is used to prepare an excited-state wave packet while the second one is less intense, but with opposite polarity and time delayed, and is employed to drag back the escaping free electron and clip the shape of the bound Rydberg wave packet, selectively increasing or decreasing a fraction of the angular-momentum components. An intelligent choice of laser parameters such as phase and amplitude helps us to control the orbital-angular-momentum composition of an electron wave packet with more facility; thus, a specified angular-momentum state with high purity can be achieved. This scheme of producing high-purity angular-momentum-state Rydberg atoms has significant application in quantum-information processing.

A Novel System for Correction of Relative Angular Displacement between Airborne Platform and UAV in Target Localization

PubMed Central

Liu, Chenglong; Liu, Jinghong; Song, Yueming; Liang, Huaidan

2017-01-01

This paper provides a system and method for correction of relative angular displacements between an Unmanned Aerial Vehicle (UAV) and its onboard strap-down photoelectric platform to improve localization accuracy. Because the angular displacements have an influence on the final accuracy, by attaching a measuring system to the platform, the texture image of platform base bulkhead can be collected in a real-time manner. Through the image registration, the displacement vector of the platform relative to its bulkhead can be calculated to further determine angular displacements. After being decomposed and superposed on the three attitude angles of the UAV, the angular displacements can reduce the coordinate transformation errors and thus improve the localization accuracy. Even a simple kind of method can improve the localization accuracy by 14.3%. PMID:28273845

A Novel System for Correction of Relative Angular Displacement between Airborne Platform and UAV in Target Localization.

PubMed

Liu, Chenglong; Liu, Jinghong; Song, Yueming; Liang, Huaidan

2017-03-04

This paper provides a system and method for correction of relative angular displacements between an Unmanned Aerial Vehicle (UAV) and its onboard strap-down photoelectric platform to improve localization accuracy. Because the angular displacements have an influence on the final accuracy, by attaching a measuring system to the platform, the texture image of platform base bulkhead can be collected in a real-time manner. Through the image registration, the displacement vector of the platform relative to its bulkhead can be calculated to further determine angular displacements. After being decomposed and superposed on the three attitude angles of the UAV, the angular displacements can reduce the coordinate transformation errors and thus improve the localization accuracy. Even a simple kind of method can improve the localization accuracy by 14.3%.

Gait event detection using linear accelerometers or angular velocity transducers in able-bodied and spinal-cord injured individuals.

PubMed

Jasiewicz, Jan M; Allum, John H J; Middleton, James W; Barriskill, Andrew; Condie, Peter; Purcell, Brendan; Li, Raymond Che Tin

2006-12-01

We report on three different methods of gait event detection (toe-off and heel strike) using miniature linear accelerometers and angular velocity transducers in comparison to using standard pressure-sensitive foot switches. Detection was performed with normal and spinal-cord injured subjects. The detection of end contact (EC), normally toe-off, and initial contact (IC) normally, heel strike was based on either foot linear accelerations or foot sagittal angular velocity or shank sagittal angular velocity. The results showed that all three methods were as accurate as foot switches in estimating times of IC and EC for normal gait patterns. In spinal-cord injured subjects, shank angular velocity was significantly less accurate (p<0.02). We conclude that detection based on foot linear accelerations or foot angular velocity can correctly identify the timing of IC and EC events in both normal and spinal-cord injured subjects.

Multiplier method may be unreliable to predict the timing of temporary hemiepiphysiodesis for coronal angular deformity.

PubMed

Wu, Zhenkai; Ding, Jing; Zhao, Dahang; Zhao, Li; Li, Hai; Liu, Jianlin

2017-07-10

The multiplier method was introduced by Paley to calculate the timing for temporary hemiepiphysiodesis. However, this method has not been verified in terms of clinical outcome measure. We aimed to (1) predict the rate of angular correction per year (ACPY) at the various corresponding ages by means of multiplier method and verify the reliability based on the data from the published studies and (2) screen out risk factors for deviation of prediction. A comprehensive search was performed in the following electronic databases: Cochrane, PubMed, and EMBASE™. A total of 22 studies met the inclusion criteria. If the actual value of ACPY from the collected date was located out of the range of the predicted value based on the multiplier method, it was considered as the deviation of prediction (DOP). The associations of patient characteristics with DOP were assessed with the use of univariate logistic regression. Only one article was evaluated as moderate evidence; the remaining articles were evaluated as poor quality. The rate of DOP was 31.82%. In the detailed individual data of included studies, the rate of DOP was 55.44%. The multiplier method is not reliable in predicting the timing for temporary hemiepiphysiodesis, even though it is prone to be more reliable for the younger patients with idiopathic genu coronal deformity.

The angular distribution of solar wind ˜20-200 keV superhalo electrons at quiet times

NASA Astrophysics Data System (ADS)

Yang, Liu; Wang, Linghua; Li, Gang; He, Jiansen; Salem, Chadi S.; Tu, Chuanyi; Wimmer-Schweingruber, Robert F.; Bale, Stuart D.

2016-03-01

We present a comprehensive study of the angular distribution of ˜20-200 keV superhalo electrons measured at 1 AU by the WIND 3DP instrument during quiet times from 1995 January through 2005 December. According to the interplanetary magnetic field, we re-bin the observed electron pitch angle distributions to obtain the differential flux, Jout (Jin), of electrons traveling outward from (inward toward) the Sun, and define the anisotropy of superhalo electrons as A =2/(Jo u t-Ji n) Jo u t+Ji n at a given energy. We found that for out in ˜96% of the selected quiet-time samples, superhalo electrons have isotropic angular distributions, while for ˜3% (˜1%) of quiet-time samples, superhalo electrons are outward-anisotropic (inward-anisotropic). All three groups of angular distributions show no correlation with the local solar wind plasma, interplanetary magnetic field and turbulence. Furthermore, the superhalo electron spectral index shows no correlation with the spectral index of local solar wind turbulence. These quiet-time superhalo electrons may be accelerated by nonthermal processes related to the solar wind source and strongly scattered/ reflected in the interplanetary medium, or could be formed due to the electron acceleration through the interplanetary medium.

Whole-body angular momentum during stair ascent and descent.

PubMed

Silverman, Anne K; Neptune, Richard R; Sinitski, Emily H; Wilken, Jason M

2014-04-01

The generation of whole-body angular momentum is essential in many locomotor tasks and must be regulated in order to maintain dynamic balance. However, angular momentum has not been investigated during stair walking, which is an activity that presents a biomechanical challenge for balance-impaired populations. We investigated three-dimensional whole-body angular momentum during stair ascent and descent and compared it to level walking. Three-dimensional body-segment kinematic and ground reaction force (GRF) data were collected from 30 healthy subjects. Angular momentum was calculated using a 13-segment whole-body model. GRFs, external moment arms and net joint moments were used to interpret the angular momentum results. The range of frontal plane angular momentum was greater for stair ascent relative to level walking. In the transverse and sagittal planes, the range of angular momentum was smaller in stair ascent and descent relative to level walking. Significant differences were also found in the ground reaction forces, external moment arms and net joint moments. The sagittal plane angular momentum results suggest that individuals alter angular momentum to effectively counteract potential trips during stair ascent, and reduce the range of angular momentum to avoid falling forward during stair descent. Further, significant differences in joint moments suggest potential neuromuscular mechanisms that account for the differences in angular momentum between walking conditions. These results provide a baseline for comparison to impaired populations that have difficulty maintaining dynamic balance, particularly during stair ascent and descent. Copyright © 2014 Elsevier B.V. All rights reserved.

The cluster-cluster correlation function. [of galaxies

NASA Technical Reports Server (NTRS)

Postman, M.; Geller, M. J.; Huchra, J. P.

1986-01-01

The clustering properties of the Abell and Zwicky cluster catalogs are studied using the two-point angular and spatial correlation functions. The catalogs are divided into eight subsamples to determine the dependence of the correlation function on distance, richness, and the method of cluster identification. It is found that the Corona Borealis supercluster contributes significant power to the spatial correlation function to the Abell cluster sample with distance class of four or less. The distance-limited catalog of 152 Abell clusters, which is not greatly affected by a single system, has a spatial correlation function consistent with the power law Xi(r) = 300r exp -1.8. In both the distance class four or less and distance-limited samples the signal in the spatial correlation function is a power law detectable out to 60/h Mpc. The amplitude of Xi(r) for clusters of richness class two is about three times that for richness class one clusters. The two-point spatial correlation function is sensitive to the use of estimated redshifts.

A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique

NASA Astrophysics Data System (ADS)

Shivananju, B. N.; Yamdagni, S.; Vasu, R. M.; Asokan, S.

2012-12-01

Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than ±0.1 mrad (≈0.036 mrad) and has an excellent repeatability with an error of less than 2%.

Angular Multigrid Preconditioner for Krylov-Based Solution Techniques Applied to the Sn Equations with Highly Forward-Peaked Scattering

NASA Astrophysics Data System (ADS)

Turcksin, Bruno; Ragusa, Jean C.; Morel, Jim E.

2012-01-01

It is well known that the diffusion synthetic acceleration (DSA) methods for the Sn equations become ineffective in the Fokker-Planck forward-peaked scattering limit. In response to this deficiency, Morel and Manteuffel (1991) developed an angular multigrid method for the 1-D Sn equations. This method is very effective, costing roughly twice as much as DSA per source iteration, and yielding a maximum spectral radius of approximately 0.6 in the Fokker-Planck limit. Pautz, Adams, and Morel (PAM) (1999) later generalized the angular multigrid to 2-D, but it was found that the method was unstable with sufficiently forward-peaked mappings between the angular grids. The method was stabilized via a filtering technique based on diffusion operators, but this filtering also degraded the effectiveness of the overall scheme. The spectral radius was not bounded away from unity in the Fokker-Planck limit, although the method remained more effective than DSA. The purpose of this article is to recast the multidimensional PAM angular multigrid method without the filtering as an Sn preconditioner and use it in conjunction with the Generalized Minimal RESidual (GMRES) Krylov method. The approach ensures stability and our computational results demonstrate that it is also significantly more efficient than an analogous DSA-preconditioned Krylov method.

Photoelectron Angular Distributions of Transition Metal Dioxide Anions - a joint experimental and theoretical study

NASA Astrophysics Data System (ADS)

Iordanov, Ivan; Gunaratne, Dasitha; Harmon, Christopher; Sofo, Jorge; Castleman, A. W., Jr.

2012-02-01

Angular-resolved photoelectron spectroscopy (PES) studies of the MO2- (M=Ti, Zr, Hf, Co, Rh) clusters are presented for the first time along with theoretical calculations of their properties. We confirm previously reported non-angular PES results for the vertical detachment energies (VDE), vibrational energies and geometric structures of these clusters and further explore the effect of the 'lanthanide contraction' on the MO2- clusters by comparing the electronic spectra of 4d and 5d transition metal dioxides. Angular-resolved PES provides the angular momentum contributions to the HOMO of these clusters and we use theoretical calculations to examine the HOMO and compare to our experimental results. First-principles calculations are done using both density functional theory (DFT) and the coupled-cluster, singles, doubles and triples (CCSD(T)) methods.

Estimating stellar effective temperatures and detected angular parameters using stochastic particle swarm optimization

NASA Astrophysics Data System (ADS)

Zhang, Chuan-Xin; Yuan, Yuan; Zhang, Hao-Wei; Shuai, Yong; Tan, He-Ping

2016-09-01

Considering features of stellar spectral radiation and sky surveys, we established a computational model for stellar effective temperatures, detected angular parameters and gray rates. Using known stellar flux data in some bands, we estimated stellar effective temperatures and detected angular parameters using stochastic particle swarm optimization (SPSO). We first verified the reliability of SPSO, and then determined reasonable parameters that produced highly accurate estimates under certain gray deviation levels. Finally, we calculated 177 860 stellar effective temperatures and detected angular parameters using data from the Midcourse Space Experiment (MSX) catalog. These derived stellar effective temperatures were accurate when we compared them to known values from literatures. This research makes full use of catalog data and presents an original technique for studying stellar characteristics. It proposes a novel method for calculating stellar effective temperatures and detecting angular parameters, and provides theoretical and practical data for finding information about radiation in any band.

Detrended Partial-Cross-Correlation Analysis: A New Method for Analyzing Correlations in Complex System

PubMed Central

Yuan, Naiming; Fu, Zuntao; Zhang, Huan; Piao, Lin; Xoplaki, Elena; Luterbacher, Juerg

2015-01-01

In this paper, a new method, detrended partial-cross-correlation analysis (DPCCA), is proposed. Based on detrended cross-correlation analysis (DCCA), this method is improved by including partial-correlation technique, which can be applied to quantify the relations of two non-stationary signals (with influences of other signals removed) on different time scales. We illustrate the advantages of this method by performing two numerical tests. Test I shows the advantages of DPCCA in handling non-stationary signals, while Test II reveals the “intrinsic” relations between two considered time series with potential influences of other unconsidered signals removed. To further show the utility of DPCCA in natural complex systems, we provide new evidence on the winter-time Pacific Decadal Oscillation (PDO) and the winter-time Nino3 Sea Surface Temperature Anomaly (Nino3-SSTA) affecting the Summer Rainfall over the middle-lower reaches of the Yangtze River (SRYR). By applying DPCCA, better significant correlations between SRYR and Nino3-SSTA on time scales of 6 ~ 8 years are found over the period 1951 ~ 2012, while significant correlations between SRYR and PDO on time scales of 35 years arise. With these physically explainable results, we have confidence that DPCCA is an useful method in addressing complex systems. PMID:25634341

Accompanying coordinate expansion and recurrence relation method using a transfer relation scheme for electron repulsion integrals with high angular momenta and long contractions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayami, Masao; Seino, Junji; Nakai, Hiromi, E-mail: nakai@waseda.jp

An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.

Communication: Direct comparison between theory and experiment for correlated angular and product-state distributions of the ground-state and stretching-excited O(3P) + CH4 reactions

NASA Astrophysics Data System (ADS)

Czakó, Gábor

2014-06-01

Motivated by a recent experiment [H. Pan and K. Liu, J. Chem. Phys. 140, 191101 (2014)], we report a quasiclassical trajectory study of the O(3P) + CH4(vk = 0, 1) → OH + CH3 [k = 1 and 3] reactions on an ab initio potential energy surface. The computed angular distributions and cross sections correlated to the OH(v = 0, 1) + CH3(v = 0) coincident product states can be directly compared to experiment for O + CH4(v3 = 0, 1). Both theory and experiment show that the ground-state reaction is backward scattered, whereas the angular distributions shift toward sideways and forward directions upon antisymmetric stretching (v3) excitation of the reactant. Theory predicts similar behavior for the O + CH4(v1 = 1) reaction. The simulations show that stretching excitation enhances the reaction up to about 15 kcal/mol collision energy, whereas the O + CH4(vk = 1) reactions produce smaller cross sections for OH(v = 1) + CH3(v = 0) than those of O + CH4(v = 0) → OH(v = 0) + CH3(v = 0). The former finding agrees with experiment and the latter awaits for confirmation. The computed cold OH rotational distributions of O + CH4(v = 0) are in good agreement with experiment.

Communication: direct comparison between theory and experiment for correlated angular and product-state distributions of the ground-state and stretching-excited O((3)P) + CH4 reactions.

PubMed

Czakó, Gábor

2014-06-21

Motivated by a recent experiment [H. Pan and K. Liu, J. Chem. Phys. 140, 191101 (2014)], we report a quasiclassical trajectory study of the O((3)P) + CH4(vk = 0, 1) → OH + CH3 [k = 1 and 3] reactions on an ab initio potential energy surface. The computed angular distributions and cross sections correlated to the OH(v = 0, 1) + CH3(v = 0) coincident product states can be directly compared to experiment for O + CH4(v3 = 0, 1). Both theory and experiment show that the ground-state reaction is backward scattered, whereas the angular distributions shift toward sideways and forward directions upon antisymmetric stretching (v3) excitation of the reactant. Theory predicts similar behavior for the O + CH4(v1 = 1) reaction. The simulations show that stretching excitation enhances the reaction up to about 15 kcal/mol collision energy, whereas the O + CH4(vk = 1) reactions produce smaller cross sections for OH(v = 1) + CH3(v = 0) than those of O + CH4(v = 0) → OH(v = 0) + CH3(v = 0). The former finding agrees with experiment and the latter awaits for confirmation. The computed cold OH rotational distributions of O + CH4(v = 0) are in good agreement with experiment.

Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

PubMed

Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

2018-05-01

We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some

Methods and devices for measuring orbital angular momentum states of electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMorran, Benjamin J.; Harvey, Tyler R.

A device for measuring electron orbital angular momentum states in an electron microscope includes the following components aligned sequentially in the following order along an electron beam axis: a phase unwrapper (U) that is a first electrostatic refractive optical element comprising an electrode and a conductive plate, where the electrode is aligned perpendicular to the conductive plate; a first electron lens system (L1); a phase corrector (C) that is a second electrostatic refractive optical element comprising an array of electrodes with alternating electrostatic bias; and a second electron lens system (L2). The phase unwrapper may be a needle electrode ormore » knife edge electrode.« less

Massive star formation by accretion. II. Rotation: how to circumvent the angular momentum barrier?

NASA Astrophysics Data System (ADS)

Haemmerlé, L.; Eggenberger, P.; Meynet, G.; Maeder, A.; Charbonnel, C.; Klessen, R. S.

2017-06-01

Context. Rotation plays a key role in the star-formation process, from pre-stellar cores to pre-main-sequence (PMS) objects. Understanding the formation of massive stars requires taking into account the accretion of angular momentum during their PMS phase. Aims: We study the PMS evolution of objects destined to become massive stars by accretion, focusing on the links between the physical conditions of the environment and the rotational properties of young stars. In particular, we look at the physical conditions that allow the production of massive stars by accretion. Methods: We present PMS models computed with a new version of the Geneva Stellar Evolution code self-consistently including accretion and rotation according to various accretion scenarios for mass and angular momentum. We describe the internal distribution of angular momentum in PMS stars accreting at high rates and we show how the various physical conditions impact their internal structures, evolutionary tracks, and rotation velocities during the PMS and the early main sequence. Results: We find that the smooth angular momentum accretion considered in previous studies leads to an angular momentum barrier and does not allow the formation of massive stars by accretion. A braking mechanism is needed in order to circumvent this angular momentum barrier. This mechanism has to be efficient enough to remove more than two thirds of the angular momentum from the inner accretion disc. Due to the weak efficiency of angular momentum transport by shear instability and meridional circulation during the accretion phase, the internal rotation profiles of accreting stars reflect essentially the angular momentum accretion history. As a consequence, careful choice of the angular momentum accretion history allows circumvention of any limitation in mass and velocity, and production of stars of any mass and velocity compatible with structure equations.

BONNSAI: correlated stellar observables in Bayesian methods

NASA Astrophysics Data System (ADS)

Schneider, F. R. N.; Castro, N.; Fossati, L.; Langer, N.; de Koter, A.

2017-02-01

In an era of large spectroscopic surveys of stars and big data, sophisticated statistical methods become more and more important in order to infer fundamental stellar parameters such as mass and age. Bayesian techniques are powerful methods because they can match all available observables simultaneously to stellar models while taking prior knowledge properly into account. However, in most cases it is assumed that observables are uncorrelated which is generally not the case. Here, we include correlations in the Bayesian code Bonnsai by incorporating the covariance matrix in the likelihood function. We derive a parametrisation of the covariance matrix that, in addition to classical uncertainties, only requires the specification of a correlation parameter that describes how observables co-vary. Our correlation parameter depends purely on the method with which observables have been determined and can be analytically derived in some cases. This approach therefore has the advantage that correlations can be accounted for even if information for them are not available in specific cases but are known in general. Because the new likelihood model is a better approximation of the data, the reliability and robustness of the inferred parameters are improved. We find that neglecting correlations biases the most likely values of inferred stellar parameters and affects the precision with which these parameters can be determined. The importance of these biases depends on the strength of the correlations and the uncertainties. For example, we apply our technique to massive OB stars, but emphasise that it is valid for any type of stars. For effective temperatures and surface gravities determined from atmosphere modelling, we find that masses can be underestimated on average by 0.5σ and mass uncertainties overestimated by a factor of about 2 when neglecting correlations. At the same time, the age precisions are underestimated over a wide range of stellar parameters. We conclude that

Angular Momentum

ERIC Educational Resources Information Center

Shakur, Asif; Sinatra, Taylor

2013-01-01

The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

Jet-hadron correlations relative to the event plane at the LHC with ALICE

NASA Astrophysics Data System (ADS)

Mazer, Joel; Alice Collaboration

2017-11-01

In ultra relativistic heavy-ion collisions at the Large Hadron Collider (LHC), conditions are met to produce a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP). Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. The outgoing partons scatter and interact with the medium, leading to a manifestation of medium modifications of jets in the final state, known as jet quenching. Within the framework of perturbative QCD, jet production is well understood in pp collisions. We use jets measured in pp interactions as a baseline reference for comparing to heavy-ion collision systems to detect and study jet quenching. The jet quenching mechanism can be studied through the angular correlations of jets with charged hadrons and is examined in transverse momentum (pT) bins of the jets, pT bins of the associated hadrons, and as a function of collision centrality. A robust and precise background subtraction method is used in this analysis to remove the complex, flow dominated, heavy-ion background. The analysis of angular correlations for different orientations of the jet relative to the event plane allows for the study of the path-length dependence of medium modifications to jets. The event plane dependence of azimuthal angular correlations of charged hadrons with respect to the axis of an R = 0.2 reconstructed full (charged + neutral) jet in Pb-Pb collisions at √{sNN} = 2.76 TeV in ALICE is presented. Results are compared for three angular bins of the jet relative to the event plane in mid-peripheral events. The yields relative to the event plane are presented and then quantified through yield ratio calculations. The results show no significant path-length dependence on the medium modifications.

Bringing the cross-correlation method up to date

NASA Technical Reports Server (NTRS)

Statler, Thomas

1995-01-01

The cross-correlation (XC) method of Tonry & Davis (1979, AJ, 84, 1511) is generalized to arbitrary parametrized line profiles. In the new algorithm the correlation function itself, rather than the observed galaxy spectrum, is fitted by the model line profile: this removes much of the complication in the error analysis caused by template mismatch. Like the Fourier correlation quotient (FCQ) method of Bender (1990, A&A, 229, 441), the inferred line profiles are, up to a normalization constant, independent of template mismatch as long as there are no blended lines. The standard reduced chi(exp 2) is a good measure of the fit of the inferred velocity distribution, largely decoupled from the fit of the spectral template. The updated XC method performs as well as other recently developed methods, with the added virtue of conceptual simplicity.

An angular biasing method using arbitrary convex polyhedra for Monte Carlo radiation transport calculations

DOE PAGES

Kulesza, Joel A.; Solomon, Clell J.; Kiedrowski, Brian C.

2018-01-02

This paper presents a new method for performing angular biasing in Monte Carlo radiation transport codes using arbitrary convex polyhedra to define regions of interest toward which to project particles (DXTRAN regions). The method is derived and is implemented using axis-aligned right parallelepipeds (AARPPs) and arbitrary convex polyhedra. Attention is also paid to possible numerical complications and areas for future refinement. A series of test problems are executed with void, purely absorbing, purely scattering, and 50% absorbing/50% scattering materials. For all test problems tally results using AARPP and polyhedral DXTRAN regions agree with analog and/or spherical DXTRAN results within statisticalmore » uncertainties. In cases with significant scattering the figure of merit (FOM) using AARPP or polyhedral DXTRAN regions is lower than with spherical regions despite the ability to closely fit the tally region. This is because spherical DXTRAN processing is computationally less expensive than AARPP or polyhedral DXTRAN processing. Thus, it is recommended that the speed of spherical regions be considered versus the ability to closely fit the tally region with an AARPP or arbitrary polyhedral region. It is also recommended that short calculations be made prior to final calculations to compare the FOM for the various DXTRAN geometries because of the influence of the scattering behavior.« less

Angular dependence of the nanoDot OSL dosimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight/OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system. Methods: Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, asmore » well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX. Results: When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found. Conclusions: A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions.« less

Relationship between cardiopulmonary responses and isokinetic moments: the optimal angular velocity for muscular endurance

PubMed Central

Lee, Chan-Bok; Eun, Denny; Kim, Kang-Ho; Park, Jae-Wan; Jee, Yong-Seok

2017-01-01

Most protocols for testing and rehabilitation for recovery and improvement of muscular endurance have been set at 180°/sec, 240°/sec, and 300°/sec. These protocols can cause confusion to clinical providers or other researchers. This study was aimed at investigating the optimal isokinetic angular speed for measuring or developing muscular endurance after assessing the relationship between cardiopulmonary responses and isokinetic moments. This study was conducted with 31 male and female college students. Graded exercise test and body composition were measured as well as the isokinetic moments of the knee muscles at three angular speeds: 180°/sec, 240°/sec, and 300°/sec. The specific isokinetic moments of knee muscles that were measured included: peak torque (PT) and total work (TW) on extensor (e) and flexor (f) of knee joints, which were denoted as ePT180, fPT180, eTW180, fTW180, ePT240, fPT240, eTW240, fTW240, ePT300, fPT300, eTW300, and fTW300 according to the three angular speeds. Spearman correlation test was used to examine the relationship between the sum means of cardiopulmonary responses and the variables of isokinetic moments. This study confirmed that the optimal angular speed for testing or training for muscular endurance was 180°/sec, which showed a stronger relationship between cardiopulmonary responses and isokinetic moments. Therefore, this angular speed is recommended for testing and training for muscular endurance of the knee joints. PMID:28503531

Relationship between cardiopulmonary responses and isokinetic moments: the optimal angular velocity for muscular endurance.

PubMed

Lee, Chan-Bok; Eun, Denny; Kim, Kang-Ho; Park, Jae-Wan; Jee, Yong-Seok

2017-04-01

Most protocols for testing and rehabilitation for recovery and improvement of muscular endurance have been set at 180°/sec, 240°/sec, and 300°/sec. These protocols can cause confusion to clinical providers or other researchers. This study was aimed at investigating the optimal isokinetic angular speed for measuring or developing muscular endurance after assessing the relationship between cardiopulmonary responses and isokinetic moments. This study was conducted with 31 male and female college students. Graded exercise test and body composition were measured as well as the isokinetic moments of the knee muscles at three angular speeds: 180°/sec, 240°/sec, and 300°/sec. The specific isokinetic moments of knee muscles that were measured included: peak torque (PT) and total work (TW) on extensor (e) and flexor (f) of knee joints, which were denoted as ePT180, fPT180, eTW180, fTW180, ePT240, fPT240, eTW240, fTW240, ePT300, fPT300, eTW300, and fTW300 according to the three angular speeds. Spearman correlation test was used to examine the relationship between the sum means of cardiopulmonary responses and the variables of isokinetic moments. This study confirmed that the optimal angular speed for testing or training for muscular endurance was 180°/sec, which showed a stronger relationship between cardiopulmonary responses and isokinetic moments. Therefore, this angular speed is recommended for testing and training for muscular endurance of the knee joints.

Chirality and the angular momentum of light

PubMed Central

Götte, Jörg B.; Barnett, Stephen M.; Yao, Alison M.

2017-01-01

Chirality is exhibited by objects that cannot be rotated into their mirror images. It is far from obvious that this has anything to do with the angular momentum of light, which owes its existence to rotational symmetries. There is nevertheless a subtle connection between chirality and the angular momentum of light. We demonstrate this connection and, in particular, its significance in the context of chiral light–matter interactions. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069764

Absolute angular encoder based on optical diffraction

NASA Astrophysics Data System (ADS)

Wu, Jian; Zhou, Tingting; Yuan, Bo; Wang, Liqiang

2015-08-01

A new encoding method for absolute angular encoder based on optical diffraction was proposed in the present study. In this method, an encoder disc is specially designed that a series of elements are uniformly spaced in one circle and each element is consisted of four diffraction gratings, which are tilted in the directions of 30°, 60°, -60° and -30°, respectively. The disc is illuminated by a coherent light and the diffractive signals are received. The positions of diffractive spots are used for absolute encoding and their intensities are for subdivision, which is different from the traditional optical encoder based on transparent/opaque binary principle. Since the track's width in the disc is not limited in the diffraction pattern, it provides a new way to solve the contradiction between the size and resolution, which is good for minimization of encoder. According to the proposed principle, the diffraction pattern disc with a diameter of 40 mm was made by lithography in the glass substrate. A prototype of absolute angular encoder with a resolution of 20" was built up. Its maximum error was tested as 78" by comparing with a small angle measuring system based on laser beam deflection.

Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles.

PubMed

Zhao, Wei; Ji, Songbai

2017-04-01

Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29-17.89 % in the whole brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9 %) but not pattern (correlation coefficient of 0.94-0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91 % on average, with a typical range of 0-6 %). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future.

Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles

PubMed Central

Zhao, Wei; Ji, Songbai

2016-01-01

Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles, and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction, and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29–17.89% in the whole-brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9%) but not pattern (correlation coefficient of 0.94–0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91% on average, with a typical range of 0–6%). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future. PMID:27644441

Correlation Plenoptic Imaging.

PubMed

D'Angelo, Milena; Pepe, Francesco V; Garuccio, Augusto; Scarcelli, Giuliano

2016-06-03

Plenoptic imaging is a promising optical modality that simultaneously captures the location and the propagation direction of light in order to enable three-dimensional imaging in a single shot. However, in standard plenoptic imaging systems, the maximum spatial and angular resolutions are fundamentally linked; thereby, the maximum achievable depth of field is inversely proportional to the spatial resolution. We propose to take advantage of the second-order correlation properties of light to overcome this fundamental limitation. In this Letter, we demonstrate that the correlation in both momentum and position of chaotic light leads to the enhanced refocusing power of correlation plenoptic imaging with respect to standard plenoptic imaging.

Correlation Plenoptic Imaging

NASA Astrophysics Data System (ADS)

D'Angelo, Milena; Pepe, Francesco V.; Garuccio, Augusto; Scarcelli, Giuliano

2016-06-01

Plenoptic imaging is a promising optical modality that simultaneously captures the location and the propagation direction of light in order to enable three-dimensional imaging in a single shot. However, in standard plenoptic imaging systems, the maximum spatial and angular resolutions are fundamentally linked; thereby, the maximum achievable depth of field is inversely proportional to the spatial resolution. We propose to take advantage of the second-order correlation properties of light to overcome this fundamental limitation. In this Letter, we demonstrate that the correlation in both momentum and position of chaotic light leads to the enhanced refocusing power of correlation plenoptic imaging with respect to standard plenoptic imaging.

Method and apparatus for fiber optic multiple scattering suppression

NASA Technical Reports Server (NTRS)

Ackerson, Bruce J. (Inventor)

2000-01-01

The instant invention provides a method and apparatus for use in laser induced dynamic light scattering which attenuates the multiple scattering component in favor of the single scattering component. The preferred apparatus utilizes two light detectors that are spatially and/or angularly separated and which simultaneously record the speckle pattern from a single sample. The recorded patterns from the two detectors are then cross correlated in time to produce one point on a composite single/multiple scattering function curve. By collecting and analyzing cross correlation measurements that have been taken at a plurality of different spatial/angular positions, the signal representative of single scattering may be differentiated from the signal representative of multiple scattering, and a near optimum detector separation angle for use in taking future measurements may be determined.

Interferometric measurement of angular motion.

PubMed

Peña Arellano, Fabián Erasmo; Panjwani, Hasnain; Carbone, Ludovico; Speake, Clive C

2013-04-01

This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10(-11) rad/Hz from audioband down to 100 mHz and an angular measurement range of more than ±1°.

A January angular momentum balance in the OSU two-level atmospheric general circulation model

NASA Technical Reports Server (NTRS)

Kim, J.-W.; Grady, W.

1982-01-01

The present investigation is concerned with an analysis of the atmospheric angular momentum balance, based on the simulation data of the Oregon State University two-level atmospheric general circulation model (AGCM). An attempt is also made to gain an understanding of the involved processes. Preliminary results on the angular momentum and mass balance in the AGCM are shown. The basic equations are examined, and questions of turbulent momentum transfer are investigated. The methods of analysis are discussed, taking into account time-averaged balance equations, time and longitude-averaged balance equations, mean meridional circulation, the mean meridional balance of relative angular momentum, and standing and transient components of motion.

Jet angularity measurements for single inclusive jet production

NASA Astrophysics Data System (ADS)

Kang, Zhong-Bo; Lee, Kyle; Ringer, Felix

2018-04-01

We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.

Orbital angular momentum (OAM) spectrum correction in free space optical communication.

PubMed

Liu, Yi-Dong; Gao, Chunqing; Qi, Xiaoqing; Weber, Horst

2008-05-12

Orbital angular momentum (OAM) of laser beams has potential application in free space optical communication, but it is sensitive against pointing instabilities of the beam, i.e. shift (lateral displacement) and tilt (deflection of the beam). This work proposes a method to correct the distorted OAM spectrum by using the mean square value of the orbital angular momentum as an indicator. Qualitative analysis is given, and the numerical simulation is carried out for demonstration. The results show that the mean square value can be used to determine the beam axis of the superimposed helical beams. The initial OAM spectrum can be recovered.

Reverse design of a bull's eye structure for oblique incidence and wider angular transmission efficiency.

PubMed

Yamada, Akira; Terakawa, Mitsuhiro

2015-04-10

We present a design method of a bull's eye structure with asymmetric grooves for focusing oblique incident light. The design method is capable of designing transmission peaks to a desired oblique angle with capability of collecting light from a wider range of angles. The bull's eye groove geometry for oblique incidence is designed based on the electric field intensity pattern around an isolated subwavelength aperture on a thin gold film at oblique incidence, calculated by the finite difference time domain method. Wide angular transmission efficiency is successfully achieved by overlapping two different bull's eye groove patterns designed with different peak angles. Our novel design method would overcome the angular limitations of the conventional methods.

Angular structure of jet quenching within a hybrid strong/weak coupling model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casalderrey-Solana, Jorge; Gulhan, Doga Can; Milhano, José Guilherme

Within the context of a hybrid strong/weak coupling model of jet quenching, we study the modification of the angular distribution of the energy within jets in heavy ion collisions, as partons within jet showers lose energy and get kicked as they traverse the strongly coupled plasma produced in the collision. To describe the dynamics transverse to the jet axis, we add the effects of transverse momentum broadening into our hybrid construction, introducing a parameter K≡qˆ/T3K≡q^/T3 that governs its magnitude. We show that, because of the quenching of the energy of partons within a jet, even when K ≠ 0 themore » jets that survive with some specified energy in the final state are narrower than jets with that energy in proton-proton collisions. For this reason, many standard observables are rather insensitive to K. We also propose a new differential jet shape ratio observable in which the effects of transverse momentum broadening are apparent. We also analyze the response of the medium to the passage of the jet through it, noting that the momentum lost by the jet appears as the momentum of a wake in the medium. After freezeout this wake becomes soft particles with a broad angular distribution but with net momentum in the jet direction, meaning that the wake contributes to what is reconstructed as a jet. Thus, this effect must be included in any description of the angular structure of the soft component of a jet. We show that the particles coming from the response of the medium to the momentum and energy deposited in it leads to a correlation between the momentum of soft particles well separated from the jet in angle with the direction of the jet momentum, and find qualitative but not quantitative agreement with experimental data on observables designed to extract such a correlation. Generally, by confronting the results that we obtain upon introducing transverse momentum broadening and the response of the medium to the jet with available jet data, we highlight

Angular structure of jet quenching within a hybrid strong/weak coupling model

DOE PAGES

Casalderrey-Solana, Jorge; Gulhan, Doga Can; Milhano, José Guilherme; ...

2017-03-27

Within the context of a hybrid strong/weak coupling model of jet quenching, we study the modification of the angular distribution of the energy within jets in heavy ion collisions, as partons within jet showers lose energy and get kicked as they traverse the strongly coupled plasma produced in the collision. To describe the dynamics transverse to the jet axis, we add the effects of transverse momentum broadening into our hybrid construction, introducing a parameter K≡qˆ/T3K≡q^/T3 that governs its magnitude. We show that, because of the quenching of the energy of partons within a jet, even when K ≠ 0 themore » jets that survive with some specified energy in the final state are narrower than jets with that energy in proton-proton collisions. For this reason, many standard observables are rather insensitive to K. We also propose a new differential jet shape ratio observable in which the effects of transverse momentum broadening are apparent. We also analyze the response of the medium to the passage of the jet through it, noting that the momentum lost by the jet appears as the momentum of a wake in the medium. After freezeout this wake becomes soft particles with a broad angular distribution but with net momentum in the jet direction, meaning that the wake contributes to what is reconstructed as a jet. Thus, this effect must be included in any description of the angular structure of the soft component of a jet. We show that the particles coming from the response of the medium to the momentum and energy deposited in it leads to a correlation between the momentum of soft particles well separated from the jet in angle with the direction of the jet momentum, and find qualitative but not quantitative agreement with experimental data on observables designed to extract such a correlation. Generally, by confronting the results that we obtain upon introducing transverse momentum broadening and the response of the medium to the jet with available jet data, we highlight

Task Space Angular Velocity Blending for Real-Time Trajectory Generation

NASA Technical Reports Server (NTRS)

Volpe, Richard A. (Inventor)

1997-01-01

The invention is embodied in a method of controlling a robot manipulator moving toward a target frame F(sub 0) with a target velocity v(sub 0) including a linear target velocity v and an angular target velocity omega(sub 0) to smoothly and continuously divert the robot manipulator to a subsequent frame F(sub 1) by determining a global transition velocity v(sub 1), the global transition velocity including a linear transition velocity v(sub 1) and an angular transition velocity omega(sub 1), defining a blend time interval 2(tau)(sub 0) within which the global velocity of the robot manipulator is to be changed from a global target velocity v(sub 0) to the global transition velocity v(sub 1) and dividing the blend time interval 2(tau)(sub 0) into discrete time segments (delta)t. During each one of the discrete time segments delta t of the blend interval 2(tau)(sub 0), a blended global velocity v of the manipulator is computed as a blend of the global target velocity v(sub 0) and the global transition velocity v(sub 1), the blended global velocity v including a blended angular velocity omega and a blended linear velocity v, and then, the manipulator is rotated by an incremental rotation corresponding to an integration of the blended angular velocity omega over one discrete time segment (delta)t.

Test-retest reliability of lower limb isokinetic endurance in COPD: A comparison of angular velocities

PubMed Central

Ribeiro, Fernanda; Lépine, Pierre-Alexis; Garceau-Bolduc, Corine; Coats, Valérie; Allard, Étienne; Maltais, François; Saey, Didier

2015-01-01

Background The purpose of this study was to determine and compare the test-retest reliability of quadriceps isokinetic endurance testing at two knee angular velocities in patients with chronic obstructive pulmonary disease (COPD). Methods After one familiarization session, 14 patients with moderate to severe COPD (mean age 65±4 years; forced expiratory volume in 1 second (FEV1) 55%±18% predicted) performed two quadriceps isokinetic endurance tests on two separate occasions within a 5–7-day interval. Quadriceps isokinetic endurance tests consisted of 30 maximal knee extensions at angular velocities of 90° and 180° per second, performed in random order. Test-retest reliability was assessed for peak torque, muscle endurance, work slope, work fatigue index, and changes in FEV1 for dyspnea and leg fatigue from rest to the end of the test. The intraclass correlation coefficient, minimal detectable change, and limits of agreement were calculated. Results High test-retest reliability was identified for peak torque and muscle total work at both velocities. Work fatigue index was considered reliable at 90° per second but not at 180° per second. A lower reliability was identified for dyspnea and leg fatigue scores at both angular velocities. Conclusion Despite a limited sample size, our findings support the use of a 30-maximal repetition isokinetic muscle testing procedure at angular velocities of 90° and 180° per second in patients with moderate to severe COPD. Endurance measurement (total isokinetic work) at 90° per second was highly reliable, with a minimal detectable change at the 95% confidence level of 10%. Peak torque and fatigue index could also be assessed reliably at 90° per second. Evaluation of dyspnea and leg fatigue using the modified Borg scale of perceived exertion was poorly reliable and its clinical usefulness is questionable. These results should be useful in the design and interpretation of future interventions aimed at improving muscle

Methods and systems for determining angular orientation of a drill string

DOEpatents

Cobern, Martin E.

2010-03-23

Preferred methods and systems generate a control input based on a periodically-varying characteristic associated with the rotation of a drill string. The periodically varying characteristic can be correlated with the magnetic tool face and gravity tool face of a rotating component of the drill string, so that the control input can be used to initiate a response in the rotating component as a function of gravity tool face.

The reliability and reproducibility of cephalometric measurements: a comparison of conventional and digital methods

PubMed Central

AlBarakati, SF; Kula, KS; Ghoneima, AA

2012-01-01

Objective The aim of this study was to assess the reliability and reproducibility of angular and linear measurements of conventional and digital cephalometric methods. Methods A total of 13 landmarks and 16 skeletal and dental parameters were defined and measured on pre-treatment cephalometric radiographs of 30 patients. The conventional and digital tracings and measurements were performed twice by the same examiner with a 6 week interval between measurements. The reliability within the method was determined using Pearson's correlation coefficient (r2). The reproducibility between methods was calculated by paired t-test. The level of statistical significance was set at p < 0.05. Results All measurements for each method were above 0.90 r2 (strong correlation) except maxillary length, which had a correlation of 0.82 for conventional tracing. Significant differences between the two methods were observed in most angular and linear measurements except for ANB angle (p = 0.5), angle of convexity (p = 0.09), anterior cranial base (p = 0.3) and the lower anterior facial height (p = 0.6). Conclusion In general, both methods of conventional and digital cephalometric analysis are highly reliable. Although the reproducibility of the two methods showed some statistically significant differences, most differences were not clinically significant. PMID:22184624

A Novel Angular Acceleration Sensor Based on the Electromagnetic Induction Principle and Investigation of Its Calibration Tests

PubMed Central

Zhao, Hao; Feng, Hao

2013-01-01

An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor. PMID:23941911

Transverse angular momentum in topological photonic crystals

NASA Astrophysics Data System (ADS)

Deng, Wei-Min; Chen, Xiao-Dong; Zhao, Fu-Li; Dong, Jian-Wen

2018-01-01

Engineering local angular momentum of structured light fields in real space enables applications in many fields, in particular, the realization of unidirectional robust transport in topological photonic crystals with a non-trivial Berry vortex in momentum space. Here, we show transverse angular momentum modes in silicon topological photonic crystals when considering transverse electric polarization. Excited by a chiral external source with either transverse spin angular momentum or transverse phase vortex, robust light flow propagating along opposite directions is observed in several kinds of sharp-turn interfaces between two topologically-distinct silicon photonic crystals. A transverse orbital angular momentum mode with alternating phase vortex exists at the boundary of two such photonic crystals. In addition, unidirectional transport is robust to the working frequency even when the ring size or location of the pseudo-spin source varies in a certain range, leading to the superiority of the broadband photonic device. These findings enable one to make use of transverse angular momentum, a kind of degree of freedom, to achieve unidirectional robust transport in the telecom region and other potential applications in integrated photonic circuits, such as on-chip robust delay lines.

Staggering of angular momentum distribution in fission

NASA Astrophysics Data System (ADS)

Tamagno, Pierre; Litaize, Olivier

2018-03-01

We review here the role of angular momentum distributions in the fission process. To do so the algorithm implemented in the FIFRELIN code [?] is detailed with special emphasis on the place of fission fragment angular momenta. The usual Rayleigh distribution used for angular momentum distribution is presented and the related model derivation is recalled. Arguments are given to justify why this distribution should not hold for low excitation energy of the fission fragments. An alternative ad hoc expression taking into account low-lying collectiveness is presented as has been implemented in the FIFRELIN code. Yet on observables currently provided by the code, no dramatic impact has been found. To quantify the magnitude of the impact of the low-lying staggering in the angular momentum distribution, a textbook case is considered for the decay of the 144Ba nucleus with low excitation energy.

Electro-optic analyzer of angular momentum hyperentanglement

PubMed Central

Wu, Ziwen; Chen, Lixiang

2016-01-01

Characterizing a high-dimensional entanglement is fundamental in quantum information applications. Here, we propose a theoretical scheme to analyze and characterize the angular momentum hyperentanglement that two photons are entangled simultaneously in spin and orbital angular momentum. Based on the electro-optic sampling with a proposed hyper-entanglement analyzer and the simple matrix operation using Cramer rule, our simulations show that it is possible to retrieve effectively both the information about the degree of polarization entanglement and the spiral spectrum of high-dimensional orbital angular momentum entanglement. PMID:26911530

Analytic solution of the Spencer-Lewis angular-spatial moments equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippone, W.L.

A closed-form solution for the angular-spatial moments of the Spencer-Lewis equation is presented that is valid for infinite homogeneous media. From the moments, the electron density distribution as a function of position and path length (energy) is reconstructed for several sample problems involving plane isotropic sources of electrons in aluminium. The results are in excellent agreement with those determined numerically using the streaming ray method. The primary use of the closed form solution will most likely be to generate accurate electron transport benchmark solutions. In principle, the electron density as a function of space, path length, and direction can bemore » determined for planar sources of arbitrary angular distribution.« less

Interferometric measurement of angular motion

NASA Astrophysics Data System (ADS)

Peña Arellano, Fabián Erasmo; Panjwani, Hasnain; Carbone, Ludovico; Speake, Clive C.

2013-04-01

This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10-11 rad/sqrt{textrm {Hz}} from audioband down to 100 mHz and an angular measurement range of more than ±1°.

Angular photogrammetric analysis of the soft tissue profile in 12-year-old southern Chinese.

PubMed

Leung, Cindi Sy; Yang, Yanqi; Wong, Ricky Wk; Hägg, Urban; Lo, John; McGrath, Colman

2014-12-24

To quantify average angular measurements that define the soft tissue profiles of 12-year-old southern Chinese and to determine gender differences. A random population sample of 514 12-year-old children was recruited (about 10% of a Hong Kong Chinese birth cohort). Photographs were taken in natural head posture and 12 soft tissue landmarks were located on the photos to measure 12 angular measurements using ImageJ (V1.45s) for Windows. Approximately 10% of photographs were reanalyzed and method error was calculated. Angular norm values for the 12 parameters were determined and gender differences were assessed using 2 sample T-test with 95% confidence interval. The response rate was 54.1% (278/514). Norm values for the 12 angular measurements were generated. The greatest variability was found for the nasolabial (Cm-Sn-Ls) and labiomental (Li-Sm-Pg) angles. Gender differences were found in 4 angular parameters: vertical nasal angle (N-Prn/TV) (p < 0.05), cervicomental angle (G-Pg/C-Me) (p < 0.001), facial convexity angle (G-Sn-Pg) (p < 0.01) and total facial convexity angle (G-Prn-Pg)(p < 0.01). Norm values for 12 angular measurements among 12-year-old southern Chinese children were provided and some variability noted. Gender differences were apparent in several angular measurements. This study has implications in developing norm values for southern Chinese and for comparison with other ethnic groups.

Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p +p collisions at √{s } =510 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Boer, M.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butler, C.; Butsyk, S.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Dixit, D.; Do, J. H.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Elder, T.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fukuda, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Ji, Z.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapukchyan, D.; Kapustinsky, J.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.-J.; Kim, H.-J.; Kim, M. H.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kincses, D.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kudo, S.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Leung, Y. H.; Lewis, B.; Lewis, N. A.; Li, X.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lovasz, K.; Lynch, D.; Maguire, C. F.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mihalik, D. E.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagai, K.; Nagamiya, S.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Richford, D.; Rinn, T.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Runchey, J.; Ryu, M. S.; Safonov, A. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Smith, K. L.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takahara, A.; Takeda, A.; Taketani, A.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarnai, G.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vargyas, M.; Vazquez-Carson, S.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vukman, N.; Vznuzdaev, E.; Wang, X. R.; Wang, Z.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; Wolin, S.; Wong, C. P.; Woody, C. L.; Wysocki, M.; Xia, B.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zhou, S.; Zou, L.; Phenix Collaboration

2017-04-01

Dihadron and isolated direct photon-hadron angular correlations are measured in p +p collisions at √{s }=510 GeV . Correlations of charged hadrons of 0.7 correlations and factorization breaking effects. The widths are found to decrease with pTtrig , which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p +p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.

Generating partially correlated noise—A comparison of methods

PubMed Central

Hartmann, William M.; Cho, Yun Jin

2011-01-01

There are three standard methods for generating two channels of partially correlated noise: the two-generator method, the three-generator method, and the symmetric-generator method. These methods allow an experimenter to specify a target cross correlation between the two channels, but actual generated noises show statistical variability around the target value. Numerical experiments were done to compare the variability for those methods as a function of the number of degrees of freedom. The results of the experiments quantify the stimulus uncertainty in diverse binaural psychoacoustical experiments: incoherence detection, perceived auditory source width, envelopment, noise localization∕lateralization, and the masking level difference. The numerical experiments found that when the elemental generators have unequal powers, the different methods all have similar variability. When the powers are constrained to be equal, the symmetric-generator method has much smaller variability than the other two. PMID:21786899

Angular Momentum and Galaxy Formation Revisited

NASA Astrophysics Data System (ADS)

Romanowsky, Aaron J.; Fall, S. Michael

2012-12-01

Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j sstarf and mass M sstarf (thus extending earlier work by Fall). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as 10 effective radii, and find that data at two effective radii are generally sufficient to estimate total j sstarf reliably. Our results contravene suggestions that ellipticals could harbor large reservoirs of hidden j sstarf in their outer regions owing to angular momentum transport in major mergers. We then carry out a comprehensive analysis of extended kinematic data from the literature for a sample of ~100 nearby bright galaxies of all types, placing them on a diagram of j sstarf versus M sstarf. The ellipticals and spirals form two parallel j sstarf-M sstarf tracks, with log-slopes of ~0.6, which for the spirals are closely related to the Tully-Fisher relation, but for the ellipticals derives from a remarkable conspiracy between masses, sizes, and rotation velocities. The ellipticals contain less angular momentum on average than spirals of equal mass, with the quantitative disparity depending on the adopted K-band stellar mass-to-light ratios of the galaxies: it is a factor of ~3-4 if mass-to-light ratio variations are neglected for simplicity, and ~7 if they are included. We decompose the spirals into disks and bulges and find that these subcomponents follow j sstarf-M sstarf trends similar to the overall ones for spirals and ellipticals. The lenticulars have an intermediate trend, and we propose that the morphological types of galaxies reflect disk and bulge subcomponents that follow separate, fundamental j sstarf

ANGULAR MOMENTUM AND GALAXY FORMATION REVISITED

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romanowsky, Aaron J.; Fall, S. Michael

2012-12-15

Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j{sub *} and mass M{sub *} (thus extending earlier work by Fall). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as 10 effective radii, and find that data at two effective radii aremore » generally sufficient to estimate total j{sub *} reliably. Our results contravene suggestions that ellipticals could harbor large reservoirs of hidden j{sub *} in their outer regions owing to angular momentum transport in major mergers. We then carry out a comprehensive analysis of extended kinematic data from the literature for a sample of {approx}100 nearby bright galaxies of all types, placing them on a diagram of j{sub *} versus M{sub *}. The ellipticals and spirals form two parallel j{sub *}-M{sub *} tracks, with log-slopes of {approx}0.6, which for the spirals are closely related to the Tully-Fisher relation, but for the ellipticals derives from a remarkable conspiracy between masses, sizes, and rotation velocities. The ellipticals contain less angular momentum on average than spirals of equal mass, with the quantitative disparity depending on the adopted K-band stellar mass-to-light ratios of the galaxies: it is a factor of {approx}3-4 if mass-to-light ratio variations are neglected for simplicity, and {approx}7 if they are included. We decompose the spirals into disks and bulges and find that these subcomponents follow j{sub *}-M{sub *} trends similar to the overall ones for spirals and ellipticals. The lenticulars have an intermediate trend, and we propose that the morphological types of galaxies reflect disk and bulge subcomponents that

Angular relational signature-based chest radiograph image view classification.

PubMed

Santosh, K C; Wendling, Laurent

2018-01-22

In a computer-aided diagnosis (CAD) system, especially for chest radiograph or chest X-ray (CXR) screening, CXR image view information is required. Automatically separating CXR image view, frontal and lateral can ease subsequent CXR screening process, since the techniques may not equally work for both views. We present a novel technique to classify frontal and lateral CXR images, where we introduce angular relational signature through force histogram to extract features and apply three different state-of-the-art classifiers: multi-layer perceptron, random forest, and support vector machine to make a decision. We validated our fully automatic technique on a set of 8100 images hosted by the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH), and achieved an accuracy close to 100%. Our method outperforms the state-of-the-art methods in terms of processing time (less than or close to 2 s for the whole test data) while the accuracies can be compared, and therefore, it justifies its practicality. Graphical Abstract Interpreting chest X-ray (CXR) through the angular relational signature.

HO2 rovibrational eigenvalue studies for nonzero angular momentum

NASA Astrophysics Data System (ADS)

Wu, Xudong T.; Hayes, Edward F.

1997-08-01

An efficient parallel algorithm is reported for determining all bound rovibrational energy levels for the HO2 molecule for nonzero angular momentum values, J=1, 2, and 3. Performance tests on the CRAY T3D indicate that the algorithm scales almost linearly when up to 128 processors are used. Sustained performance levels of up to 3.8 Gflops have been achieved using 128 processors for J=3. The algorithm uses a direct product discrete variable representation (DVR) basis and the implicitly restarted Lanczos method (IRLM) of Sorensen to compute the eigenvalues of the polyatomic Hamiltonian. Since the IRLM is an iterative method, it does not require storage of the full Hamiltonian matrix—it only requires the multiplication of the Hamiltonian matrix by a vector. When the IRLM is combined with a formulation such as DVR, which produces a very sparse matrix, both memory and computation times can be reduced dramatically. This algorithm has the potential to achieve even higher performance levels for larger values of the total angular momentum.

Relaxation method of compensation in an optical correlator

NASA Technical Reports Server (NTRS)

Juday, Richard D.; Daiuto, Brian J.

1987-01-01

An iterative method is proposed for the sharpening of programmable filters in a 4-f optical correlator. Continuously variable spatial light modulators (SLMs) permit the fine adjustment of optical processing filters so as to compensate for the departures from ideal behavior of a real optical system. Although motivated by the development of continuously variable phase-only SLMs, the proposed sharpening method is also applicable to amplitude modulators and, with appropriate adjustments, to binary modulators as well. A computer simulation is presented that illustrates the potential effectiveness of the method: an image is placed on the input to the correlator, and its corresponding phase-only filter is adjusted (allowed to relax) so as to produce a progressively brighter and more centralized peak in the correlation plane. The technique is highly robust against the form of the system's departure from ideal behavior.

Fatigue influences lower extremity angular velocities during a single-leg drop vertical jump.

PubMed

Tamura, Akihiro; Akasaka, Kiyokazu; Otsudo, Takahiro; Shiozawa, Junya; Toda, Yuka; Yamada, Kaori

2017-03-01

[Purpose] Fatigue alters lower extremity landing strategies and decreases the ability to attenuate impact during landing. The purpose of this study was to reveal the influence of fatigue on dynamic alignment and joint angular velocities in the lower extremities during a single leg landing. [Subjects and Methods] The 34 female college students were randomly assigned to either the fatigue or control group. The fatigue group performed single-leg drop vertical jumps before, and after, the fatigue protocol, which was performed using a bike ergometer. Lower extremity kinematic data were acquired using a three-dimensional motion analysis system. The ratio of each variable (%), for the pre-fatigue to post-fatigue protocols, were calculated to compare differences between each group. [Results] Peak hip and knee flexion angular velocities increased significantly in the fatigue group compared with the control group. Furthermore, hip flexion angular velocity increased significantly between each group at 40 milliseconds after initial ground contact. [Conclusion] Fatigue reduced the ability to attenuate impact by increasing angular velocities in the direction of hip and knee flexion during landings. These findings indicate a requirement to evaluate movement quality over time by measuring hip and knee flexion angular velocities in landings during fatigue conditions.

Autocollimation system for measuring angular deformations with reflector designed by quaternionic method

NASA Astrophysics Data System (ADS)

Hoang, Phong V.; Konyakhin, Igor A.

2017-06-01

Autocollimators are widely used for angular measurements in instrument-making and the manufacture of elements of optical systems (wedges, prisms, plane-parallel plates) to check their shape parameters (rectilinearity, parallelism and planarity) and retrieve their optical parameters (curvature radii, measure and test their flange focusing). Autocollimator efficiency is due to the high sensitivity of the autocollimation method to minor rotations of the reflecting control element or the controlled surface itself. We consider using quaternions to optimize reflector parameters during autocollimation measurements as compared to the matrix technique. Mathematical model studies have demonstrated that the orthogonal positioning of the two basic unchanged directions of the tetrahedral reflector of the autocollimator is optimal by the criterion of reducing measurement errors where the axis of actual rotation is in a bisecting position towards them. Computer results are presented of running quaternion models that yielded conditions for diminishing measurement errors provided apriori information is available on the position of rotation axis. A practical technique is considered for synthesizing the parameters of the tetrahedral reflector that employs the newly-retrieved relationships. Following the relationships found between the angles of the tetrahedral reflector and the angles of the parameters of its initial orientation, an applied technique was developed to synthesize the control element for autocollimation measurements in case apriori information is available on the axis of actual rotation during monitoring measurements of shaft or pipeline deformation.

Quantum orbital angular momentum of elliptically symmetric light

NASA Astrophysics Data System (ADS)

Plick, William N.; Krenn, Mario; Fickler, Robert; Ramelow, Sven; Zeilinger, Anton

2013-03-01

We present a quantum-mechanical analysis of the orbital angular momentum of a class of recently discovered elliptically symmetric stable light fields—the so-called Ince-Gauss modes. We study, in a fully quantum formalism, how the orbital angular momentum of these beams varies with their ellipticity, and we discover several compelling features, including nonmonotonic behavior, stable beams with real continuous (noninteger) orbital angular momenta, and orthogonal modes with the same orbital angular momenta. We explore, and explain in detail, the reasons for this behavior. These features may have applications in quantum key distribution, atom trapping, and quantum informatics in general—as the ellipticity opens up an alternative way of navigating the spatial photonic Hilbert space.

Difference in perception of angular displacement according to applied waveforms.

PubMed

Kushiro, Keisuke; Goto, Fumiyuki

2013-05-01

This study shows that the differences in the waveforms of angular rotation affect the perception and memory of angular displacement. During daily life, when we turn our head during various activities, our brain calculates how much angular displacement our head has undergone. However, how we obtain an accurate estimation of this angular displacement remains unclarified. This study aims to clarify this issue by investigating the perception and memory of passive rotation for three different waveforms of angular velocity rotation (sinusoidal (sine), triangle, and step). Thirteen healthy young subjects sitting on a servo-controlled chair were passively rotated at 60° or 120° about the earth-vertical axis by using one of these three angular velocity waveforms. They then attempted to reproduce the rotation angle by rotating the chair in the same direction in which they had been passively rotated using a handheld controller. The gain (reproduced angle/passively rotated angle) was calculated and used for the evaluation of the perception and memory of angular rotation. The gain for step rotation was larger than that for sine and triangle rotations, with statistical significance. This confirms that the difference in the waveforms of angular rotation affects the perception and memory of angular displacement.

Angular-velocity control approach for stance-control orthoses.

PubMed

Lemaire, Edward D; Goudreau, Louis; Yakimovich, Terris; Kofman, Jonathan

2009-10-01

Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma.

Generating partially correlated noise--a comparison of methods.

PubMed

Hartmann, William M; Cho, Yun Jin

2011-07-01

There are three standard methods for generating two channels of partially correlated noise: the two-generator method, the three-generator method, and the symmetric-generator method. These methods allow an experimenter to specify a target cross correlation between the two channels, but actual generated noises show statistical variability around the target value. Numerical experiments were done to compare the variability for those methods as a function of the number of degrees of freedom. The results of the experiments quantify the stimulus uncertainty in diverse binaural psychoacoustical experiments: incoherence detection, perceived auditory source width, envelopment, noise localization/lateralization, and the masking level difference. The numerical experiments found that when the elemental generators have unequal powers, the different methods all have similar variability. When the powers are constrained to be equal, the symmetric-generator method has much smaller variability than the other two. © 2011 Acoustical Society of America

Regionally variant collagen alignment correlates with viscoelastic properties of the disc of the human temporomandibular joint.

PubMed

Gutman, Shawn; Kim, Daniel; Tarafder, Solaiman; Velez, Sergio; Jeong, Julia; Lee, Chang H

2018-02-01

To determine the regionally variant quality of collagen alignment in human TMJ discs and its statistical correlation with viscoelastic properties. For quantitative analysis of the quality of collagen alignment, horizontal sections of human TMJ discs with Pricrosirius Red staining were imaged under circularly polarized microscopy. Mean angle and angular deviation of collagen fibers in each region were analyzed using a well-established automated image-processing for angular gradient. Instantaneous and relaxation moduli of each disc region were measured under stress-relaxation test both in tensile and compression. Then Spearman correlation analysis was performed between the angular deviation and the moduli. To understand the effect of glycosaminoglycans on the correlation, TMJ disc samples were treated by chondroitinase ABC (C-ABC). Our imaging processing analysis showed the region-variant direction of collagen alignment, consistently with previous findings. Interestingly, the quality of collagen alignment, not only the directions, was significantly different in between the regions. The angular deviation of fiber alignment in the anterior and intermediate regions were significantly smaller than the posterior region. Medial and lateral regions showed significantly bigger angular deviation than all the other regions. The regionally variant angular deviation values showed statistically significant correlation with the tensile instantaneous modulus and the relaxation modulus, partially dependent on C-ABC treatment. Our findings suggest the region-variant degree of collagen fiber alignment is likely attributed to the heterogeneous viscoelastic properties of TMJ disc that may have significant implications in development of regenerative therapy for TMJ disc. Copyright © 2017 Elsevier Ltd. All rights reserved.

Speeding up local correlation methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kats, Daniel

2014-12-28

We present two techniques that can substantially speed up the local correlation methods. The first one allows one to avoid the expensive transformation of the electron-repulsion integrals from atomic orbitals to virtual space. The second one introduces an algorithm for the residual equations in the local perturbative treatment that, in contrast to the standard scheme, does not require holding the amplitudes or residuals in memory. It is shown that even an interpreter-based implementation of the proposed algorithm in the context of local MP2 method is faster and requires less memory than the highly optimized variants of conventional algorithms.

Modeling channel interference in an orbital angular momentum-multiplexed laser link

NASA Astrophysics Data System (ADS)

Anguita, Jaime A.; Neifeld, Mark A.; Vasic, Bane V.

2009-08-01

We study the effects of optical turbulence on the energy crosstalk among constituent orbital angular momentum (OAM) states in a vortex-based multi-channel laser communication link and determine channel interference in terms of turbulence strength and OAM state separation. We characterize the channel interference as a function of C2n and transmit OAM state, and propose probability models to predict the random fluctuations in the received signals for such architecture. Simulations indicate that turbulence-induced channel interference is mutually correlated across receive channels.

Radially dependent angular acceleration of twisted light.

PubMed

Webster, Jason; Rosales-Guzmán, Carmelo; Forbes, Andrew

2017-02-15

While photons travel in a straight line at constant velocity in free space, the intensity profile of structured light may be tailored for acceleration in any degree of freedom. Here we propose a simple approach to control the angular acceleration of light. Using Laguerre-Gaussian modes as our twisted beams carrying orbital angular momentum, we show that superpositions of opposite handedness result in a radially dependent angular acceleration as they pass through a focus (waist plane). Due to conservation of orbital angular momentum, we find that propagation dynamics are complex despite the free-space medium: the outer part of the beam (rings) rotates in an opposite direction to the inner part (petals), and while the outer part accelerates, the inner part decelerates. We outline the concepts theoretically and confirm them experimentally. Such exotic structured light beams are topical due to their many applications, for instance in optical trapping and tweezing, metrology, and fundamental studies in optics.

Uniaxial angular accelerometers

NASA Astrophysics Data System (ADS)

Seleznev, A. V.; Shvab, I. A.

1985-05-01

The basic mechanical components of an angular accelerometer are the sensor, the damper, and the transducer. Penumatic dampers are simplest in construction, but the viscosity of air is very low and, therefore, dampers with special purpose oils having a high temperature stability (synthetic silicon or organosilicon oils) are most widely used. The most common types of viscous dampers are lamellar with meshed opposed arrays of fixed and movable vanes in the dashpot, piston dampers regulated by an adjustable-length capillary tube, and dampers with paddle wheel in closed tank. Another type of damper is an impact-inertial one with large masses absorbing the rotational energy upon collision with the sensor. Conventional measuring elements are resistive, capacitive, electromagnetic, photoelectric, and penumatic or hydraulic. Novel types of angular accelerometers are based on inertia of gas jets, electron beams, and ion beams, the piezoelectric effect in p-n junctions of diode and transistors, the electrokinetic effect in fluids, and cryogenic suspension of the sensor.

Curve Appeal: Exploring Individual Differences in Preference for Curved Versus Angular Objects

PubMed Central

Cotter, Katherine N.; Bertamini, Marco; Palumbo, Letizia; Vartanian, Oshin

2017-01-01

A preference for smooth curvature, as opposed to angularity, is a well-established finding for lines, two-dimensional shapes, and complex objects, but little is known about individual differences. We used two-dimensional black-and-white shapes—randomly generated irregular polygons, and arrays of circles and hexagons—and measured many individual differences, including artistic expertise, personality, and cognitive style. As expected, people preferred curved over angular stimuli, and people’s degree of curvature preference correlated across the two sets of shapes. Multilevel models showed varying patterns of interaction between shape and individual differences. For the irregular polygons, people higher in artistic expertise or openness to experience showed a greater preference for curvature. This pattern was not evident for the arrays of circles and hexagons. We discuss the results in relation to the nature of the stimuli, and we conclude that individual differences do play a role in moderating the preference for smooth curvature. PMID:28491269

The full-sky relativistic correlation function and power spectrum of galaxy number counts. Part I: theoretical aspects

NASA Astrophysics Data System (ADS)

Tansella, Vittorio; Bonvin, Camille; Durrer, Ruth; Ghosh, Basundhara; Sellentin, Elena

2018-03-01

We derive an exact expression for the correlation function in redshift shells including all the relativistic contributions. This expression, which does not rely on the distant-observer or flat-sky approximation, is valid at all scales and includes both local relativistic corrections and integrated contributions, like gravitational lensing. We present two methods to calculate this correlation function, one which makes use of the angular power spectrum Cl(z1,z2) and a second method which evades the costly calculations of the angular power spectra. The correlation function is then used to define the power spectrum as its Fourier transform. In this work theoretical aspects of this procedure are presented, together with quantitative examples. In particular, we show that gravitational lensing modifies the multipoles of the correlation function and of the power spectrum by a few percent at redshift z=1 and by up to 30% and more at z=2. We also point out that large-scale relativistic effects and wide-angle corrections generate contributions of the same order of magnitude and have consequently to be treated in conjunction. These corrections are particularly important at small redshift, z=0.1, where they can reach 10%. This means in particular that a flat-sky treatment of relativistic effects, using for example the power spectrum, is not consistent.

Correlation effects in elastic e-N2 scattering

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Lima, Marco A. P.; Gibson, Thomas L.; Mckoy, Vincent

1987-01-01

The Schwinger multichannel formulation has been applied to study the role of electron correlation in low-energy e-N2 scattering. For the five nonresonant partial-wave channels studied here, angular correlation is found to be much more important than radial correlation. The calculated total and differential cross sections agree well with experiment except for the differential cross sections at 1.5 eV.

Cross-correlation of point series using a new method

NASA Technical Reports Server (NTRS)

Strothers, Richard B.

1994-01-01

Traditional methods of cross-correlation of two time series do not apply to point time series. Here, a new method, devised specifically for point series, utilizes a correlation measure that is based in the rms difference (or, alternatively, the median absolute difference) between nearest neightbors in overlapped segments of the two series. Error estimates for the observed locations of the points, as well as a systematic shift of one series with respect to the other to accommodate a constant, but unknown, lead or lag, are easily incorporated into the analysis using Monte Carlo techniques. A methodological restriction adopted here is that one series be treated as a template series against which the other, called the target series, is cross-correlated. To estimate a significance level for the correlation measure, the adopted alternative (null) hypothesis is that the target series arises from a homogeneous Poisson process. The new method is applied to cross-correlating the times of the greatest geomagnetic storms with the times of maximum in the undecennial solar activity cycle.

Shape evolution with angular momentum in Lu isotopes

NASA Astrophysics Data System (ADS)

Kardan, Azam; Sayyah, Sepideh

2016-06-01

The nuclear potential energies of Lu isotopes with neutron number N = 90 - 98 up to high spins are computed within the framework of the unpaired cranked Nilsson-Strutinsky method. The potential and the macroscopic Lublin-Strasbourg drop (LSD) energy-surface diagrams are analyzed in terms of quadrupole deformation and triaxiality parameter. The shape evolution of these isotopes with respect to angular momentum, as well as the neutron number is studied.

Fast correlation method for passive-solar design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wray, W.O.; Biehl, F.A.; Kosiewicz, C.E.

1982-01-01

A passive-solar design manual for single-family detached residences and dormitory-type buildings is being developed. The design procedure employed in the manual is a simplification of the original monthly solar load ratio (SLR) method. The new SLR correlations involve a single constant for each system. The correlation constant appears as a scale factor permitting the use of a universal performance curve for all passive systems. Furthermore, by providing location-dependent correlations between the annual solar heating fraction (SHF) and the minimum monthly SHF, we have eliminated the need to perform an SLR calculation for each month of the heating season.

Projection of angular momentum via linear algebra

NASA Astrophysics Data System (ADS)

Johnson, Calvin W.; O'Mara, Kevin D.

2017-12-01

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. We show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications to 48Cr and 60Fe in the p f shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.

Demonstrating the conservation of angular momentum using spherical magnets

NASA Astrophysics Data System (ADS)

Lindén, Johan; Slotte, Joakim; Källman, Kjell-Mikael

2018-01-01

An experimental setup for demonstrating the conservation of angular momentum of rotating spherical magnets is described. Two spherical Nd-Fe-B magnets are placed on a double inclined plane and projected towards each other with pre-selected impact parameters ranging from zero to a few tens of millimeters. After impact, the two magnets either revolve vigorously around the common center of mass or stop immediately, depending on the value of the impact parameter. Using a pick-up coil connected to an oscilloscope, the angular frequency for the rotating magnets was measured, and an estimate for the angular momentum was obtained. A high-speed video camera captured the impact and was used for measuring linear and angular velocities of the magnets. A very good agreement between the initial angular momentum before the impact and the final angular momentum of the revolving dumbbell is observed. The two rotating magnets, and the rotating electromagnetic field emanating from them, can also be viewed as a toy model for the newly discovered gravitational waves, where two black holes collide after revolving around each other. (Enhanced online)

Integrating Multibeam Backscatter Angular Response, Mosaic and Bathymetry Data for Benthic Habitat Mapping

PubMed Central

Che Hasan, Rozaimi; Ierodiaconou, Daniel; Laurenson, Laurie; Schimel, Alexandre

2014-01-01

Multibeam echosounders (MBES) are increasingly becoming the tool of choice for marine habitat mapping applications. In turn, the rapid expansion of habitat mapping studies has resulted in a need for automated classification techniques to efficiently map benthic habitats, assess confidence in model outputs, and evaluate the importance of variables driving the patterns observed. The benthic habitat characterisation process often involves the analysis of MBES bathymetry, backscatter mosaic or angular response with observation data providing ground truth. However, studies that make use of the full range of MBES outputs within a single classification process are limited. We present an approach that integrates backscatter angular response with MBES bathymetry, backscatter mosaic and their derivatives in a classification process using a Random Forests (RF) machine-learning algorithm to predict the distribution of benthic biological habitats. This approach includes a method of deriving statistical features from backscatter angular response curves created from MBES data collated within homogeneous regions of a backscatter mosaic. Using the RF algorithm we assess the relative importance of each variable in order to optimise the classification process and simplify models applied. The results showed that the inclusion of the angular response features in the classification process improved the accuracy of the final habitat maps from 88.5% to 93.6%. The RF algorithm identified bathymetry and the angular response mean as the two most important predictors. However, the highest classification rates were only obtained after incorporating additional features derived from bathymetry and the backscatter mosaic. The angular response features were found to be more important to the classification process compared to the backscatter mosaic features. This analysis indicates that integrating angular response information with bathymetry and the backscatter mosaic, along with their derivatives

Inefficient Angular Momentum Transport in Accretion Disk Boundary Layers: Angular Momentum Belt in the Boundary Layer

NASA Astrophysics Data System (ADS)

Belyaev, Mikhail A.; Quataert, Eliot

2018-04-01

We present unstratified 3D MHD simulations of an accretion disk with a boundary layer (BL) that have a duration ˜1000 orbital periods at the inner radius of the accretion disk. We find the surprising result that angular momentum piles up in the boundary layer, which results in a rapidly rotating belt of accreted material at the surface of the star. The angular momentum stored in this belt increases monotonically in time, which implies that angular momentum transport mechanisms in the BL are inefficient and do not couple the accretion disk to the star. This is in spite of the fact that magnetic fields are advected into the BL from the disk and supersonic shear instabilities in the BL excite acoustic waves. In our simulations, these waves only carry a small fraction (˜10%) of the angular momentum required for steady state accretion. Using analytical theory and 2D viscous simulations in the R - ϕ plane, we derive an analytical criterion for belt formation to occur in the BL in terms of the ratio of the viscosity in the accretion disk to the viscosity in the BL. Our MHD simulations have a dimensionless viscosity (α) in the BL that is at least a factor of ˜100 smaller than that in the disk. We discuss the implications of these results for BL dynamics and emission.

Angular Momentum Transfer and Fractional Moment of Inertia in Pulsar Glitches

NASA Astrophysics Data System (ADS)

Eya, I. O.; Urama, J. O.; Chukwude, A. E.

2017-05-01

We use the Jodrell Bank Observatory glitch database containing 472 glitches from 165 pulsars to investigate the angular momentum transfer during rotational glitches in pulsars. Our emphasis is on pulsars with at least five glitches, of which there are 26 that exhibit 261 glitches in total. This paper identifies four pulsars in which the angular momentum transfer, after many glitches, is almost linear with time. The Lilliefore test on the cumulative distribution of glitch spin-up sizes in these glitching pulsars shows that glitch sizes in 12 pulsars are normally distributed, suggesting that their glitches originate from the same momentum reservoir. In addition, the distribution of the fractional moment of inertia (I.e., the ratio of the moment of inertia of neutron star components that are involved in the glitch process) have a single mode, unlike the distribution of fractional glitch size (Δν/ν), which is usually bimodal. The mean fractional moment of inertia in the glitching pulsars we sampled has a very weak correlation with the pulsar spin properties, thereby supporting a neutron star interior mechanism for the glitch phenomenon.

Development and validity of methods for the estimation of temporal gait parameters from heel-attached inertial sensors in younger and older adults.

PubMed

Misu, Shogo; Asai, Tsuyoshi; Ono, Rei; Sawa, Ryuichi; Tsutsumimoto, Kota; Ando, Hiroshi; Doi, Takehiko

2017-09-01

The heel is likely a suitable location to which inertial sensors are attached for the detection of gait events. However, there are few studies to detect gait events and determine temporal gait parameters using sensors attached to the heels. We developed two methods to determine temporal gait parameters: detecting heel-contact using acceleration and detecting toe-off using angular velocity data (acceleration-angular velocity method; A-V method), and detecting both heel-contact and toe-off using angular velocity data (angular velocity-angular velocity method; V-V method). The aim of this study was to examine the concurrent validity of the A-V and V-V methods against the standard method, and to compare their accuracy. Temporal gait parameters were measured in 10 younger and 10 older adults. The intra-class correlation coefficients were excellent in both methods compared with the standard method (0.80 to 1.00). The root mean square errors of stance and swing time in the A-V method were smaller than the V-V method in older adults, although there were no significant discrepancies in the other comparisons. Our study suggests that inertial sensors attached to the heels, using the A-V method in particular, provide a valid measurement of temporal gait parameters. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved grating angular sensor for LISA and MGRS

NASA Astrophysics Data System (ADS)

Sun, Ke-Xun; Lu, Patrick; Byer, Robert L.

2009-03-01

LISA requires high precision angular beam pointing and telescope steering. In this paper, we report recent results for an improved grating angular sensor. We have achieved better than 0.2 nrad/Hz1/2 at 1 kHz with 14 mW of incident power, a factor of 5 improvement over our previously reported results. At 1 Hz we achieved 1-2 nrad/Hz1/2. We realized these improvements by enclosing the grating angular sensor assembly in a vacuum chamber and mounting the optics components on a zerodur glass plate, thereby lowering the noise floor at low frequencies. Furthermore, by upgrading the electronics and thus the detector power handing capability, we also investigated sensitivity scaling versus incident laser power. The results will benefit the design of grating angular sensors.

Statistical theory of correlations in random packings of hard particles.

PubMed

Jin, Yuliang; Puckett, James G; Makse, Hernán A

2014-05-01

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the n-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), ϕ(rcp) = 0.85 ± 0.01, and random loose packing (RLP), ϕ(rlp) = 0.67 ± 0.01. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Unexpected angular or rotational deformity after corrective osteotomy

PubMed Central

2014-01-01

Background Codman’s paradox reveals a misunderstanding of geometry in orthopedic practice. Physicians often encounter situations that cannot be understood intuitively during orthopedic interventions such as corrective osteotomy. Occasionally, unexpected angular or rotational deformity occurs during surgery. This study aimed to draw the attention of orthopedic surgeons toward the concepts of orientation and rotation and demonstrate the potential for unexpected deformity after orthopedic interventions. This study focused on three situations: shoulder arthrodesis, femoral varization derotational osteotomy, and femoral derotation osteotomy. Methods First, a shoulder model was generated to calculate unexpected rotational deformity to demonstrate Codman’s paradox. Second, femoral varization derotational osteotomy was simulated using a cylinder model. Third, a reconstructed femoral model was used to calculate unexpected angular or rotational deformity during femoral derotation osteotomy. Results Unexpected external rotation was found after forward elevation and abduction of the shoulder joint. In the varization and derotation model, closed-wedge osteotomy and additional derotation resulted in an unexpected extension and valgus deformity, namely, under-correction of coxa valga. After femoral derotational osteotomy, varization and extension of the distal fragment occurred, although the extension was negligible. Conclusions Surgeons should be aware of unexpected angular deformity after surgical procedure involving bony areas. The degree of deformity differs depending on the context of the surgical procedure. However, this study reveals that notable deformities can be expected during orthopedic procedures such as femoral varization derotational osteotomy. PMID:24886469

Elongation measurement using 1-dimensional image correlation method

NASA Astrophysics Data System (ADS)

Phongwisit, Phachara; Kamoldilok, Surachart; Buranasiri, Prathan

2016-11-01

Aim of this paper was to study, setup, and calibrate an elongation measurement by using 1- Dimensional Image Correlation method (1-DIC). To confirm our method and setup correctness, we need calibration with other methods. In this paper, we used a small spring as a sample to find a result in terms of spring constant. With a fundamental of Image Correlation method, images of formed and deformed samples were compared to understand the difference between deformed process. By comparing the location of reference point on both image's pixel, the spring's elongation were calculated. Then, the results have been compared with the spring constants, which were found from Hooke's law. The percentage of 5 percent error has been found. This DIC method, then, would be applied to measure the elongation of some different kinds of small fiber samples.

Angular velocity of gravitational radiation from precessing binaries and the corotating frame

NASA Astrophysics Data System (ADS)

Boyle, Michael

2013-05-01

This paper defines an angular velocity for time-dependent functions on the sphere and applies it to gravitational waveforms from compact binaries. Because it is geometrically meaningful and has a clear physical motivation, the angular velocity is uniquely useful in helping to solve an important—and largely ignored—problem in models of compact binaries: the inverse problem of deducing the physical parameters of a system from the gravitational waves alone. It is also used to define the corotating frame of the waveform. When decomposed in this frame, the waveform has no rotational dynamics and is therefore as slowly evolving as possible. The resulting simplifications lead to straightforward methods for accurately comparing waveforms and constructing hybrids. As formulated in this paper, the methods can be applied robustly to both precessing and nonprecessing waveforms, providing a clear, comprehensive, and consistent framework for waveform analysis. Explicit implementations of all these methods are provided in accompanying computer code.

Projection of angular momentum via linear algebra

DOE PAGES

Johnson, Calvin W.; O'Mara, Kevin D.

2017-12-01

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

Projection of angular momentum via linear algebra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Calvin W.; O'Mara, Kevin D.

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

Correlation between static radiographic measurements and intersegmental angular measurements during gait using a multisegment foot model.

PubMed

Lee, Dong Yeon; Seo, Sang Gyo; Kim, Eo Jin; Kim, Sung Ju; Lee, Kyoung Min; Farber, Daniel C; Chung, Chin Youb; Choi, In Ho

2015-01-01

Radiographic examination is a widely used evaluation method in the orthopedic clinic. However, conventional radiography alone does not reflect the dynamic changes between foot and ankle segments during gait. Multiple 3-dimensional multisegment foot models (3D MFMs) have been introduced to evaluate intersegmental motion of the foot. In this study, we evaluated the correlation between static radiographic indices and intersegmental foot motion indices. One hundred twenty-five females were tested. Static radiographs of full-leg and anteroposterior (AP) and lateral foot views were performed. For hindfoot evaluation, we measured the AP tibiotalar angle (TiTA), talar tilt (TT), calcaneal pitch, lateral tibiocalcaneal angle, and lateral talcocalcaneal angle. For the midfoot segment, naviculocuboid overlap and talonavicular coverage angle were calculated. AP and lateral talo-first metatarsal angles and metatarsal stacking angle (MSA) were measured to assess the forefoot. Hallux valgus angle (HVA) and hallux interphalangeal angle were measured. In gait analysis by 3D MFM, intersegmental angle (ISA) measurements of each segment (hallux, forefoot, hindfoot, arch) were recorded. ISAs at midstance phase were most highly correlated with radiography. Significant correlations were observed between ISA measurements using MFM and static radiographic measurements in the same segment. In the hindfoot, coronal plane ISA was correlated with AP TiTA (P < .001) and TT (P = .018). In the hallux, HVA was strongly correlated with transverse ISA of the hallux (P < .001). The segmental foot motion indices at midstance phase during gait measured by 3D MFM gait analysis were correlated with the conventional radiographic indices. The observed correlation between MFM measurements at midstance phase during gait and static radiographic measurements supports the fundamental basis for the use of MFM in analysis of dynamic motion of foot segment during gait. © The Author(s) 2014.

Angular Impulse and Balance Regulation During the Golf Swing.

PubMed

Peterson, Travis J; Wilcox, Rand R; McNitt-Gray, Jill L

2016-08-01

Our aim was to determine how skilled players regulate linear and angular impulse while maintaining balance during the golf swing. Eleven highly-skilled golf players performed swings with a 6-iron and driver. Components contributing to linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force [RFh], RFh-angle, and moment arm) were quantified and compared across the group and within a player (α = .05). Net angular impulse generated by both the rear and target legs was greater for the driver than the 6-iron. Mechanisms used to regulate angular impulse generation between clubs varied across players and required coordination between the legs. Increases in net angular impulse with a driver involved increases in target leg RFh. Rear leg RFh-angle was maintained between clubs whereas target leg RFh became more aligned with the target line. Net linear impulse perpendicular to the target line remained near zero, preserving balance, while net linear impulse along the target line decreased in magnitude. These results indicate that the net angular impulse was regulated between clubs by coordinating force generation of the rear and target legs while sustaining balance throughout the task.

Motion fading is driven by perceived, not actual angular velocity.

PubMed

Kohler, P J; Caplovitz, G P; Hsieh, P-J; Sun, J; Tse, P U

2010-06-01

After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. Here we examine the relationship between such 'motion fading' and perceived angular velocity. Using several different dot patterns that generate emergent virtual contours, we demonstrate that whenever there is a difference in the perceived angular velocity of two patterns of dots that are in fact rotating at the same angular velocity, there is also a difference in the time to undergo motion fading for those two patterns. Conversely, whenever two patterns show no difference in perceived angular velocity, even if in fact rotating at different angular velocities, we find no difference in the time to undergo motion fading. Thus, motion fading is driven by the perceived rather than actual angular velocity of a rotating stimulus. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Observation of circular dichroism in photoelectron angular distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Appling, J.R.; White, M.G.; Orlando, T.M.

1986-12-01

The first observations of dichroic effects in photoelectron angular distributions are reported for photoionization of aligned molecular excited states with circularly polarized light. Photoelectron angular distributions resulting from the two-color, (2+1) REMPI of NO via the A /sup 2/summation/sup +/, v = 0, J = 3/2,5/2 excited states exhibit significant left--right asymmetry. The experimental CD angular distributions are found to be well described by the general theoretical framework recently developed by Dubs, Dixit, and McKoy and are in good qualitative agreement with their calculated REMPI--CD distributions.

Observation of circular dichroism in photoelectron angular distributions

NASA Astrophysics Data System (ADS)

Appling, Jeffrey R.; White, Michael G.; Orlando, Thomas M.; Anderson, Scott L.

1986-12-01

The first observations of dichroic effects in photoelectron angular distributions are reported for photoionization of aligned molecular excited states with circularly polarized light. Photoelectron angular distributions resulting from the two-color, (2+1) REMPI of NO via the A 2∑+, v=0, J=3/2,5/2 excited states exhibit significant left-right asymmetry. The experimental CD angular distributions are found to be well described by the general theoretical framework recently developed by Dubs, Dixit, and McKoy and are in good qualitative agreement with their calculated REMPI-CD distributions.

Energy transfer, orbital angular momentum, and discrete current in a double-ring fiber array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexeyev, C. N.; Volyar, A. V.; Yavorsky, M. A.

We study energy transfer and orbital angular momentum of supermodes in a double-ring array of evanescently coupled monomode optical fibers. The structure of supermodes and the spectra of their propagation constants are obtained. The geometrical parameters of the array, at which the energy is mostly confined within the layers, are determined. The developed method for finding the supermodes of concentric arrays is generalized for the case of multiring arrays. The orbital angular momentum carried by a supermode of a double-ring array is calculated. The discrete lattice current is introduced. It is shown that the sum of discrete currents over themore » array is a conserved quantity. The connection of the total discrete current with orbital angular momentum of discrete optical vortices is made.« less

Scalar and tensor spherical harmonics expansion of the velocity correlation in homogeneous anisotropic turbulence

DOE PAGES

Rubinstein, Robert; Kurien, Susan; Cambon, Claude

2015-06-22

The representation theory of the rotation group is applied to construct a series expansion of the correlation tensor in homogeneous anisotropic turbulence. The resolution of angular dependence is the main analytical difficulty posed by anisotropic turbulence; representation theory parametrises this dependence by a tensor analogue of the standard spherical harmonics expansion of a scalar. As a result, the series expansion is formulated in terms of explicitly constructed tensor bases with scalar coefficients determined by angular moments of the correlation tensor.

Maximum angular accuracy of pulsed laser radar in photocounting limit.

PubMed

Elbaum, M; Diament, P; King, M; Edelson, W

1977-07-01

To estimate the angular position of targets with pulsed laser radars, their images may be sensed with a fourquadrant noncoherent detector and the image photocounting distribution processed to obtain the angular estimates. The limits imposed on the accuracy of angular estimation by signal and background radiation shot noise, dark current noise, and target cross-section fluctuations are calculated. Maximum likelihood estimates of angular positions are derived for optically rough and specular targets and their performances compared with theoretical lower bounds.

Orbital angular momentum modes of high-gain parametric down-conversion

NASA Astrophysics Data System (ADS)

Beltran, Lina; Frascella, Gaetano; Perez, Angela M.; Fickler, Robert; Sharapova, Polina R.; Manceau, Mathieu; Tikhonova, Olga V.; Boyd, Robert W.; Leuchs, Gerd; Chekhova, Maria V.

2017-04-01

Light beams with orbital angular momentum (OAM) are convenient carriers of quantum information. They can also be used for imparting rotational motion to particles and providing high resolution in imaging. Due to the conservation of OAM in parametric down-conversion (PDC), signal and idler photons generated at low gain have perfectly anti-correlated OAM values. It is interesting to study the OAM properties of high-gain PDC, where the same OAM modes can be populated with large, but correlated, numbers of photons. Here we investigate the OAM spectrum of high-gain PDC and show that the OAM mode content can be controlled by varying the pump power and the configuration of the source. In our experiment, we use a source consisting of two nonlinear crystals separated by an air gap. We discuss the OAM properties of PDC radiation emitted by this source and suggest possible modifications.

A methodologic approach for normalizing angular work and velocity during isotonic and isokinetic eccentric training.

PubMed

Guilhem, Gaël; Cornu, Christophe; Guével, Arnaud

2012-01-01

Resistance exercise training commonly is performed against a constant external load (isotonic) or at a constant velocity (isokinetic). Researchers comparing the effectiveness of isotonic and isokinetic resistance-training protocols need to equalize the mechanical stimulus (work and velocity) applied. To examine whether the standardization protocol could be adjusted and applied to an eccentric training program. Controlled laboratory study. Controlled research laboratory. Twenty-one sport science male students (age = 20.6 ± 1.5 years, height = 178.0 ± 4.0 cm, mass = 74.5 ± 9.1 kg). Participants performed 9 weeks of isotonic (n = 11) or isokinetic (n = 10) eccentric training of knee extensors that was designed so they would perform the same amount of angular work at the same mean angular velocity. Angular work and angular velocity. The isotonic and isokinetic groups performed the same total amount of work (-185.2 ± 6.5 kJ and -184.4 ± 8.6 kJ, respectively) at the same angular velocity (21 ± 1°/s and 22°/s, respectively) with the same number of repetitions (8.0 and 8.0, respectively). Bland-Altman analysis showed that work (bias = 2.4%) and angular velocity (bias = 0.2%) were equalized over 9 weeks between the modes of training. The procedure developed allows angular work and velocity to be standardized over 9 weeks of isotonic and isokinetic eccentric training of the knee extensors. This method could be useful in future studies in which researchers compare neuromuscular adaptations induced by each type of training mode with respect to rehabilitating patients after musculoskeletal injury.

Angular-spectrum representation of nondiffracting X waves

NASA Astrophysics Data System (ADS)

Fagerholm, Juha; Friberg, Ari T.; Huttunen, Juhani; Morgan, David P.; Salomaa, Martti M.

1996-10-01

We derive the nondiffracting X waves, first discussed within acoustics by Lu and Greenleaf [IEEE Trans. Ultrason. Ferroelec. Freq. Contr. 39, 19 (1992)], using the general mathematical formalism based on an angular spectrum of plane waves. This serves to provide a unified treatment of not only the fundamental zeroth-order X waves of Lu and Greenleaf, but also of the lesser-known higher-order derivative X waves, first discussed here in terms of a single, universal, angular spectrum. The characteristic crossed (letter-X-like) shape and the special properties of the X waves, as well as of their angular-spectrum representation, are discussed and illustrated in detail. Asymptotically, for increasing order, the appearance of the X waves is found to transform into a triangular wedgelike waveform.

How cosmic microwave background correlations at large angles relate to mass autocorrelations in space

NASA Technical Reports Server (NTRS)

Blumenthal, George R.; Johnston, Kathryn V.

1994-01-01

The Sachs-Wolfe effect is known to produce large angular scale fluctuations in the cosmic microwave background radiation (CMBR) due to gravitational potential fluctuations. We show how the angular correlation function of the CMBR can be expressed explicitly in terms of the mass autocorrelation function xi(r) in the universe. We derive analytic expressions for the angular correlation function and its multipole moments in terms of integrals over xi(r) or its second moment, J(sub 3)(r), which does not need to satisfy the sort of integral constraint that xi(r) must. We derive similar expressions for bulk flow velocity in terms of xi and J(sub 3). One interesting result that emerges directly from this analysis is that, for all angles theta, there is a substantial contribution to the correlation function from a wide range of distance r and that radial shape of this contribution does not vary greatly with angle.

Improved Time-Lapsed Angular Scattering Microscopy of Single Cells

NASA Astrophysics Data System (ADS)

Cannaday, Ashley E.

By measuring angular scattering patterns from biological samples and fitting them with a Mie theory model, one can estimate the organelle size distribution within many cells. Quantitative organelle sizing of ensembles of cells using this method has been well established. Our goal is to develop the methodology to extend this approach to the single cell level, measuring the angular scattering at multiple time points and estimating the non-nuclear organelle size distribution parameters. The diameters of individual organelle-size beads were successfully extracted using scattering measurements with a minimum deflection angle of 20 degrees. However, the accuracy of size estimates can be limited by the angular range detected. In particular, simulations by our group suggest that, for cell organelle populations with a broader size distribution, the accuracy of size prediction improves substantially if the minimum angle of detection angle is 15 degrees or less. The system was therefore modified to collect scattering angles down to 10 degrees. To confirm experimentally that size predictions will become more stable when lower scattering angles are detected, initial validations were performed on individual polystyrene beads ranging in diameter from 1 to 5 microns. We found that the lower minimum angle enabled the width of this delta-function size distribution to be predicted more accurately. Scattering patterns were then acquired and analyzed from single mouse squamous cell carcinoma cells at multiple time points. The scattering patterns exhibit angular dependencies that look unlike those of any single sphere size, but are well-fit by a broad distribution of sizes, as expected. To determine the fluctuation level in the estimated size distribution due to measurement imperfections alone, formaldehyde-fixed cells were measured. Subsequent measurements on live (non-fixed) cells revealed an order of magnitude greater fluctuation in the estimated sizes compared to fixed cells. With

Improved methods of performing coherent optical correlation

NASA Technical Reports Server (NTRS)

Husain-Abidi, A. S.

1972-01-01

Coherent optical correlators are described in which complex spatial filters are recorded by a quasi-Fourier transform method. The high-pass spatial filtering effects (due to the dynamic range of photographic films) normally encountered in Vander Lugt type complex filters are not present in this system. Experimental results for both transmittive as well as reflective objects are presented. Experiments are also performed by illuminating the object with diffused light. A correlator using paraboloidal mirror segments as the Fourier-transforming element is also described.

Local Field Response Method Phenomenologically Introducing Spin Correlations

NASA Astrophysics Data System (ADS)

Tomaru, Tatsuya

2018-03-01

The local field response (LFR) method is a way of searching for the ground state in a similar manner to quantum annealing. However, the LFR method operates on a classical machine, and quantum effects are introduced through a priori information and through phenomenological means reflecting the states during the computations. The LFR method has been treated with a one-body approximation, and therefore, the effect of entanglement has not been sufficiently taken into account. In this report, spin correlations are phenomenologically introduced as one of the effects of entanglement, by which multiple tunneling at anticrossing points is taken into account. As a result, the accuracy of solutions for a 128-bit system increases by 31% compared with that without spin correlations.

Measurement of irregularities in angular velocities of rotating assemblies in memory devices on magnetic carriers

NASA Technical Reports Server (NTRS)

Virakas, G. I.; Matsyulevichyus, R. A.; Minkevichyus, K. P.; Potsyus, Z. Y.; Shirvinskas, B. D.

1973-01-01

Problems in measurement of irregularities in angular velocity of rotating assemblies in memory devices with rigid and flexible magnetic data carriers are discussed. A device and method for determination of change in angular velocities in various frequency and rotation rate ranges are examined. A schematic diagram of a photoelectric sensor for recording the signal pulses is provided. Mathematical models are developed to show the amount of error which can result from misalignment of the test equipment.

Lunar Occultations as a Simple Tool for High Angular Resolution Astronomy

NASA Astrophysics Data System (ADS)

Richichi, Andrea

1999-08-01

At the turn of the millennium, modern astronomy is seeing the creation of several new impressive facilities. Among them, large telescopes and long baseline interferometers are beginning to break the limitations imposed by seeing and to push our angular resolution limits at the level of the millisecond of arc. In this race for the state-of-the-art in angular resolution, one should not forget the considerable aid which has been provided for some decades by the more humble technique of lunar occultations. Although burdened with obvious limitations in the choice of the sources, this latter method has two main features that can make it attractive for the modern amateur astronomer: it is simple, and can be implemented also at realtively small telescopes.

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC.

PubMed

Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Caines, H; Calderón De La Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Deng, W S; Derevschikov, A A; Didenko, L; Dietel, T; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Filimonov, K; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Majka, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moore, C F; Morozov, V; De Moura, M M; Munhoz, M G; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Rykov, V; Sakrejda, I; Salur, S; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Shvetcov, V S; Skoro, G; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto De Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thomas, J H; Thompson, M; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Buren, G Van; VanderMolen, A M; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N

2003-01-24

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Measurement of angular velocity in the perception of rotation.

PubMed

Barraza, José F; Grzywacz, Norberto M

2002-09-01

Humans are sensitive to the parameters of translational motion, namely, direction and speed. At the same time, people have special mechanisms to deal with more complex motions, such as rotations and expansions. One wonders whether people may also be sensitive to the parameters of these complex motions. Here, we report on a series of experiments that explore whether human subjects can use angular velocity to evaluate how fast a rotational motion is. In four experiments, subjects were required to perform a task of speed-of-rotation discrimination by comparing two annuli of different radii in a temporal 2AFC paradigm. Results showed that humans could rely on a sensitive measurement of angular velocity to perform this discrimination task. This was especially true when the quality of the rotational signal was high (given by the number of dots composing the annulus). When the signal quality decreased, a bias towards linear velocity of 5-80% appeared, suggesting the existence of separate mechanisms for angular and linear velocity. This bias was independent from the reference radius. Finally, we asked whether the measurement of angular velocity required a rigid rotation, that is, whether the visual system makes only one global estimate of angular velocity. For this purpose, a random-dot disk was built such that all the dots were rotating with the same tangential speed, irrespectively of radius. Results showed that subjects do not estimate a unique global angular velocity, but that they perceive a non-rigid disk, with angular velocity falling inversely proportionally with radius.

Intrinsic alignments in redMaPPer clusters - I. Central galaxy alignments and angular segregation of satellites

NASA Astrophysics Data System (ADS)

Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E.; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Baxter, Eric J.

2016-11-01

The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes and the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Finally, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.

Angular analysis of the B 0 → K *0 μ + μ - decay using 3 fb-1 of integrated luminosity

NASA Astrophysics Data System (ADS)

Aaij, R.; Abellán Beteta, C.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borisyak, M.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Fabianska, M.; Falabella, A.; Färber, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parker, W.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zhukov, V.; Zucchelli, S.

2016-02-01

An angular analysis of the B 0 → K *0(→ K + π -) μ + μ - decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb-1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K + π - system in an S-wave configuration. The angular observables and their correlations are reported in bins of q 2, the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q 2-dependent decay amplitudes in the region 1.1 < q 2 < 6.0 GeV2/ c 4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions. [Figure not available: see fulltext.

Joint Angular Velocity in Spastic Gait and the Influence of Muscle-Tendon Lengthening*

PubMed Central

GRANATA, KEVIN P.; ABEL, MARK F.; DAMIANO, DIANE L.

2006-01-01

Background Joint angular velocity (the rate of flexion and extension of a joint) is related to the dynamics of muscle activation and force generation during walking. Therefore, the goal of this research was to examine the joint angular velocity in normal and spastic gait and changes resulting from muscle-tendon lengthening (recession and tenotomy) in patients who have spastic cerebral palsy. Methods The gait patterns of forty patients who had been diagnosed with spastic cerebral palsy (mean age, 8.3 years; range, 3.7 to 14.8 years) and of seventy-three age-matched, normally developing subjects were evaluated with three-dimensional motion analysis and electromyography. The patients who had cerebral palsy were evaluated before muscle-tendon lengthening and nine months after treatment. Results The gait patterns of the patients who had cerebral palsy were characterized by increased flexion of the knee in the stance phase, premature plantar flexion of the ankle, and reduced joint angular velocities compared with the patterns of the normally developing subjects. Even though muscle-tendon lengthening altered sagittal joint angles in gait, the joint angular velocities were generally unchanged at the hip and knee. Only the ankle demonstrated modified angular velocities, including reduced dorsiflexion velocity at foot-strike and improved dorsiflexion velocity through midstance, after treatment. Electromyographic changes included reduced amplitude of the gastrocnemius-soleus during the loading phase and decreased knee coactivity (the ratio of quadriceps and hamstring activation) at toe-off. Principal component analyses showed that, compared with joint-angle data, joint angular velocity was better able to discriminate between the gait patterns of the normal and cerebral palsy groups. Conclusions This study showed that muscle-tendon lengthening corrects biomechanical alignment as reflected by changes in sagittal joint angles. However, joint angular velocity and

The Small Angular Oscillations of Airplanes in Steady Flight

NASA Technical Reports Server (NTRS)

Norton, F H

1924-01-01

This investigation was carried out by the National Advisory Committee for Aeronautics at the request of the Army Air Service to provide data concerning the small angular oscillations of several types of airplanes in steady flight under various atmospheric conditions. The data are of use in the design of bomb sights and other aircraft instruments. The method used consisted in flying the airplane steadily in one direction for at least one minute, while recording the angle of the airplane with the sun by means of a kymograph. The results show that the oscillations differ but little for airplanes of various types, but that the condition of the atmosphere is an important factor. The average angular excursion from the mean in smooth air is 0.8 degrees in pitch, 1.4 degrees in roll, and 0.9 degrees in yaw, without special instruments to aid the pilot in holding steady conditions. In bumpy air the values given above are increased about 50 per cent. (author)

Angular-dependent polarization-insensitive filter fashioned with zero-contrast grating.

PubMed

Gao, Xumin; Wu, Tong; Xu, Yin; Li, Xin; Bai, Dan; Zhu, Gangyi; Zhu, Hongbo; Wang, Yongjin

2015-06-15

We report here an angular-dependent polarization-insensitive filter fashioned with a free-standing zero-contrast grating (ZCG), which is implemented on an HfO(2)/Silicon platform. The spectral characteristics are investigated by rigorous coupled-wave analysis method and measured on angular-resolved micro-reflectance system. The proposed ZCG structure experimentally shows that the polarization-insensitive resonances occur at 595nm for the incidence angle θ of 12.8° and 500nm for the incidence angle θ of 14.2°. When the incident light is normal to the grating surface, the ZCG device generates yellow and red colors for p- and s-polarization, respectively. The experimental results are in good agreement with the simulations, which indicate that the free-standing ZCG device is promising for polarization-insensitive filter and polarization-controlled tunable color filter.

Grating angle magnification enhanced angular sensor and scanner

NASA Technical Reports Server (NTRS)

Sun, Ke-Xun (Inventor); Byer, Robert L. (Inventor)

2009-01-01

An angular magnification effect of diffraction is exploited to provide improved sensing and scanning. This effect is most pronounced for a normal or near-normal incidence angle in combination with a grazing diffraction angle, so such configurations are preferred. Angular sensitivity can be further enhanced because the width of the diffracted beam can be substantially less than the width of the incident beam. Normal incidence configurations with two symmetric diffracted beams are preferred, since rotation and vertical displacement can be readily distinguished. Increased sensitivity to vertical displacement can be provided by incorporating an interferometer into the measurement system. Quad cell detectors can be employed to provide sensitivity to rotation about the grating surface normal. A 2-D grating can be employed to provide sensitivity to angular displacements in two different planes (e.g., pitch and yaw). Combined systems can provide sensitivity to vertical displacement and to all three angular degrees of freedom.

Correlations in Scattered X-Ray Laser Pulses Reveal Nanoscale Structural Features of Viruses

NASA Astrophysics Data System (ADS)

Kurta, Ruslan P.; Donatelli, Jeffrey J.; Yoon, Chun Hong; Berntsen, Peter; Bielecki, Johan; Daurer, Benedikt J.; DeMirci, Hasan; Fromme, Petra; Hantke, Max Felix; Maia, Filipe R. N. C.; Munke, Anna; Nettelblad, Carl; Pande, Kanupriya; Reddy, Hemanth K. N.; Sellberg, Jonas A.; Sierra, Raymond G.; Svenda, Martin; van der Schot, Gijs; Vartanyants, Ivan A.; Williams, Garth J.; Xavier, P. Lourdu; Aquila, Andrew; Zwart, Peter H.; Mancuso, Adrian P.

2017-10-01

We use extremely bright and ultrashort pulses from an x-ray free-electron laser (XFEL) to measure correlations in x rays scattered from individual bioparticles. This allows us to go beyond the traditional crystallography and single-particle imaging approaches for structure investigations. We employ angular correlations to recover the three-dimensional (3D) structure of nanoscale viruses from x-ray diffraction data measured at the Linac Coherent Light Source. Correlations provide us with a comprehensive structural fingerprint of a 3D virus, which we use both for model-based and ab initio structure recovery. The analyses reveal a clear indication that the structure of the viruses deviates from the expected perfect icosahedral symmetry. Our results anticipate exciting opportunities for XFEL studies of the structure and dynamics of nanoscale objects by means of angular correlations.

The Angular Momentum Distribution and Baryon Content of Star-forming Galaxies at z ˜ 1-3

NASA Astrophysics Data System (ADS)

Burkert, A.; Förster Schreiber, N. M.; Genzel, R.; Lang, P.; Tacconi, L. J.; Wisnioski, E.; Wuyts, S.; Bandara, K.; Beifiori, A.; Bender, R.; Brammer, G.; Chan, J.; Davies, R.; Dekel, A.; Fabricius, M.; Fossati, M.; Kulkarni, S.; Lutz, D.; Mendel, J. T.; Momcheva, I.; Nelson, E. J.; Naab, T.; Renzini, A.; Saglia, R.; Sharples, R. M.; Sternberg, A.; Wilman, D.; Wuyts, E.

2016-08-01

We analyze the angular momenta of massive star-forming galaxies (SFGs) at the peak of the cosmic star formation epoch (z ˜ 0.8-2.6). Our sample of ˜360 log(M */M ⊙) ˜ 9.3-11.8 SFGs is mainly based on the KMOS3D and SINS/zC-SINF surveys of Hα kinematics, and collectively provides a representative subset of the massive star-forming population. The inferred halo scale angular momentum distribution is broadly consistent with that theoretically predicted for their dark matter halos, in terms of mean spin parameter < λ > ˜ 0.037 and its dispersion (σ logλ ˜ 0.2). Spin parameters correlate with the disk radial scale and with their stellar surface density, but do not depend significantly on halo mass, stellar mass, or redshift. Our data thus support the long-standing assumption that on average, even at high redshifts, the specific angular momentum of disk galaxies reflects that of their dark matter halos (j d = j DM). The lack of correlation between λ × (j d /j DM) and the nuclear stellar density Σ*(1 kpc) favors a scenario where disk-internal angular momentum redistribution leads to “compaction” inside massive high-redshift disks. For our sample, the inferred average stellar to dark matter mass ratio is ˜2%, consistent with abundance matching results. Including the molecular gas, the total baryonic disk to dark matter mass ratio is ˜5% for halos near 1012 M ⊙, which corresponds to 31% of the cosmologically available baryons, implying that high-redshift disks are strongly baryon dominated. Based on observations obtained at the Very Large Telescope of the European Southern Observatory, Paranal, Chile (ESO Programme IDs 075.A-0466, 076.A-0527, 079.A-0341, 080.A-0330, 080.A-0339, 080.A-0635, 081.B-0568, 081.A-0672, 082.A-0396, 183.A-0781, 087.A-0081, 088.A-0202, 088.A-0209, 091.A-0126, 092.A-0091, 093.A-0079, 094.A-0217, 095.A-0047, 096.A-0025).

Time-resolved orbital angular momentum spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noyan, Mehmet A.; Kikkawa, James M.

We introduce pump-probe magneto-orbital spectroscopy, wherein Laguerre-Gauss optical pump pulses impart orbital angular momentum to the electronic states of a material and subsequent dynamics are studied with 100 fs time resolution. The excitation uses vortex modes that distribute angular momentum over a macroscopic area determined by the spot size, and the optical probe studies the chiral imbalance of vortex modes reflected off the sample. First observations in bulk GaAs yield transients that evolve on time scales distinctly different from population and spin relaxation, as expected, but with surprisingly large lifetimes.

Angular momentum

NASA Astrophysics Data System (ADS)

Shakur, Asif; Sinatra, Taylor

2013-12-01

The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in the physics laboratory. Many traditional physics experiments can now be performed very conveniently in a pedagogically enlightening environment while simultaneously reducing the laboratory budget substantially by using student-owned smartphones.

Angular Momentum Transfer and Fractional Moment of Inertia in Pulsar Glitches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eya, I. O.; Urama, J. O.; Chukwude, A. E., E-mail: innocent.eya@unn.edu.ng, E-mail: innocent.eya@gmail.com

We use the Jodrell Bank Observatory glitch database containing 472 glitches from 165 pulsars to investigate the angular momentum transfer during rotational glitches in pulsars. Our emphasis is on pulsars with at least five glitches, of which there are 26 that exhibit 261 glitches in total. This paper identifies four pulsars in which the angular momentum transfer, after many glitches, is almost linear with time. The Lilliefore test on the cumulative distribution of glitch spin-up sizes in these glitching pulsars shows that glitch sizes in 12 pulsars are normally distributed, suggesting that their glitches originate from the same momentum reservoir.more » In addition, the distribution of the fractional moment of inertia (i.e., the ratio of the moment of inertia of neutron star components that are involved in the glitch process) have a single mode, unlike the distribution of fractional glitch size (Δ ν / ν ), which is usually bimodal. The mean fractional moment of inertia in the glitching pulsars we sampled has a very weak correlation with the pulsar spin properties, thereby supporting a neutron star interior mechanism for the glitch phenomenon.« less

Untangling Galaxy Components - The Angular Momentum Parameter

NASA Astrophysics Data System (ADS)

Tabor, Martha; Merrifield, Michael; Aragon-Salamanca, Alfonso

2017-06-01

We have developed a new technique to decompose Integral Field spectral data cubes into separate bulge and disk components, allowing us to study the kinematic and stellar population properties of the individual components and how they vary with position. We present here the application of this method to a sample of fast rotator early type galaxies from the MaNGA integral field survey, and demonstrate how it can be used to explore key properties of the individual components. By extracting ages, metallicities and the angular momentum parameter lambda of the bulges and disks, we show how this method can give us new insights into the underlying structure of the galaxies and discuss what this can tell us about their evolution history.

Two-Way Gene Interaction From Microarray Data Based on Correlation Methods

PubMed Central

Alavi Majd, Hamid; Talebi, Atefeh; Gilany, Kambiz; Khayyer, Nasibeh

2016-01-01

Background Gene networks have generated a massive explosion in the development of high-throughput techniques for monitoring various aspects of gene activity. Networks offer a natural way to model interactions between genes, and extracting gene network information from high-throughput genomic data is an important and difficult task. Objectives The purpose of this study is to construct a two-way gene network based on parametric and nonparametric correlation coefficients. The first step in constructing a Gene Co-expression Network is to score all pairs of gene vectors. The second step is to select a score threshold and connect all gene pairs whose scores exceed this value. Materials and Methods In the foundation-application study, we constructed two-way gene networks using nonparametric methods, such as Spearman’s rank correlation coefficient and Blomqvist’s measure, and compared them with Pearson’s correlation coefficient. We surveyed six genes of venous thrombosis disease, made a matrix entry representing the score for the corresponding gene pair, and obtained two-way interactions using Pearson’s correlation, Spearman’s rank correlation, and Blomqvist’s coefficient. Finally, these methods were compared with Cytoscape, based on BIND, and Gene Ontology, based on molecular function visual methods; R software version 3.2 and Bioconductor were used to perform these methods. Results Based on the Pearson and Spearman correlations, the results were the same and were confirmed by Cytoscape and GO visual methods; however, Blomqvist’s coefficient was not confirmed by visual methods. Conclusions Some results of the correlation coefficients are not the same with visualization. The reason may be due to the small number of data. PMID:27621916

Characterization of the crystal structure, kinematics, stresses and rotations in angular granular quartz during compaction

DOE PAGES

Hurley, Ryan C.; Herbold, Eric B.; Pagan, Darren C.

2018-06-28

Three-dimensional X-ray diffraction (3DXRD), a method for quantifying the position, orientation and elastic strain of large ensembles of single crystals, has recently emerged as an important tool for studying the mechanical response of granular materials during compaction. Applications have demonstrated the utility of 3DXRD and X-ray computed tomography (XRCT) for assessing strains, particle stresses and orientations, inter-particle contacts and forces, particle fracture mechanics, and porosity evolution in situ . Although past studies employing 3DXRD and XRCT have elucidated the mechanics of spherical particle packings and angular particle packings with a small number of particles, there has been limited effort tomore » date in studying angular particle packings with a large number of particles and in comparing the mechanics of these packings with those composed of a large number of spherical particles. Therefore, the focus of the present paper is on the mechanics of several hundred angular particles during compaction using in situ 3DXRD to study the crystal structure, kinematics, stresses and rotations of angular quartz grains. Comparisons are also made between the compaction response of angular grains and that of spherical grains, and stress-induced twinning within individual grains is discussed.« less

Characterization of the crystal structure, kinematics, stresses and rotations in angular granular quartz during compaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurley, Ryan C.; Herbold, Eric B.; Pagan, Darren C.

Three-dimensional X-ray diffraction (3DXRD), a method for quantifying the position, orientation and elastic strain of large ensembles of single crystals, has recently emerged as an important tool for studying the mechanical response of granular materials during compaction. Applications have demonstrated the utility of 3DXRD and X-ray computed tomography (XRCT) for assessing strains, particle stresses and orientations, inter-particle contacts and forces, particle fracture mechanics, and porosity evolution in situ . Although past studies employing 3DXRD and XRCT have elucidated the mechanics of spherical particle packings and angular particle packings with a small number of particles, there has been limited effort tomore » date in studying angular particle packings with a large number of particles and in comparing the mechanics of these packings with those composed of a large number of spherical particles. Therefore, the focus of the present paper is on the mechanics of several hundred angular particles during compaction using in situ 3DXRD to study the crystal structure, kinematics, stresses and rotations of angular quartz grains. Comparisons are also made between the compaction response of angular grains and that of spherical grains, and stress-induced twinning within individual grains is discussed.« less

Polarization-polarization correlation measurement --- Experimental test of the PPCO methods

NASA Astrophysics Data System (ADS)

Droste, Ch.; Starosta, K.; Wierzchucka, A.; Morek, T.; Rohoziński, S. G.; Srebrny, J.; Wesolowski, E.; Bergstrem, M.; Herskind, B.

1998-04-01

A significant fraction of modern multidetector arrays used for "in-beam" gamma-ray spectroscopy consist of a detectors which are sensitive to linear polarization of gamma quanta. This yields the opportunity to carry out correlation measurements between the gamma rays registered in polarimeters to get information concerning spins and parities of excited nuclear states. The aim of the present work was to study the ability of the polarization- polarization correlation method (the PPCO method). The correlation between the linear polarization of one gamma quantum and the polarization of the second quantum emitted in a cascade from an oriented nucleus (due to a heavy ion reaction) was studied in detail. The appropriate formulae and methods of analysis are presented. The experimental test of the method was performed using the EUROGAM II array. The CLOVER detectors are the parts of the array used as polarimeters. The ^164Yb nucleus was produced via the ^138Ba(^30Si, 4n) reaction. It was found that the PPCO method together with the standard DCO analysis and the polarization- direction correlation method (PDCO) can be helpful for spin, parity and multipolarity assignments. The results suggest that the PPCO method can be applied to modern spectrometers in which a large number of detectors (e.g. CLOVER) are sensitive to polarization of gamma rays.

Two-Way Gene Interaction From Microarray Data Based on Correlation Methods.

PubMed

Alavi Majd, Hamid; Talebi, Atefeh; Gilany, Kambiz; Khayyer, Nasibeh

2016-06-01

Gene networks have generated a massive explosion in the development of high-throughput techniques for monitoring various aspects of gene activity. Networks offer a natural way to model interactions between genes, and extracting gene network information from high-throughput genomic data is an important and difficult task. The purpose of this study is to construct a two-way gene network based on parametric and nonparametric correlation coefficients. The first step in constructing a Gene Co-expression Network is to score all pairs of gene vectors. The second step is to select a score threshold and connect all gene pairs whose scores exceed this value. In the foundation-application study, we constructed two-way gene networks using nonparametric methods, such as Spearman's rank correlation coefficient and Blomqvist's measure, and compared them with Pearson's correlation coefficient. We surveyed six genes of venous thrombosis disease, made a matrix entry representing the score for the corresponding gene pair, and obtained two-way interactions using Pearson's correlation, Spearman's rank correlation, and Blomqvist's coefficient. Finally, these methods were compared with Cytoscape, based on BIND, and Gene Ontology, based on molecular function visual methods; R software version 3.2 and Bioconductor were used to perform these methods. Based on the Pearson and Spearman correlations, the results were the same and were confirmed by Cytoscape and GO visual methods; however, Blomqvist's coefficient was not confirmed by visual methods. Some results of the correlation coefficients are not the same with visualization. The reason may be due to the small number of data.

The Capacity Gain of Orbital Angular Momentum Based Multiple-Input-Multiple-Output System

PubMed Central

Zhang, Zhuofan; Zheng, Shilie; Chen, Yiling; Jin, Xiaofeng; Chi, Hao; Zhang, Xianmin

2016-01-01

Wireless communication using electromagnetic wave carrying orbital angular momentum (OAM) has attracted increasing interest in recent years, and its potential to increase channel capacity has been explored widely. In this paper, we compare the technique of using uniform linear array consist of circular traveling-wave OAM antennas for multiplexing with the conventional multiple-in-multiple-out (MIMO) communication method, and numerical results show that the OAM based MIMO system can increase channel capacity while communication distance is long enough. An equivalent model is proposed to illustrate that the OAM multiplexing system is equivalent to a conventional MIMO system with a larger element spacing, which means OAM waves could decrease the spatial correlation of MIMO channel. In addition, the effects of some system parameters, such as OAM state interval and element spacing, on the capacity advantage of OAM based MIMO are also investigated. Our results reveal that OAM waves are complementary with MIMO method. OAM waves multiplexing is suitable for long-distance line-of-sight (LoS) communications or communications in open area where the multi-path effect is weak and can be used in massive MIMO systems as well. PMID:27146453

Angular momentum conservation law in light-front quantum field theory

DOE PAGES

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

2017-03-31

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

Aliasing Detection and Reduction Scheme on Angularly Undersampled Light Fields.

PubMed

Xiao, Zhaolin; Wang, Qing; Zhou, Guoqing; Yu, Jingyi

2017-05-01

When using plenoptic camera for digital refocusing, angular undersampling can cause severe (angular) aliasing artifacts. Previous approaches have focused on avoiding aliasing by pre-processing the acquired light field via prefiltering, demosaicing, reparameterization, and so on. In this paper, we present a different solution that first detects and then removes angular aliasing at the light field refocusing stage. Different from previous frequency domain aliasing analysis, we carry out a spatial domain analysis to reveal whether the angular aliasing would occur and uncover where in the image it would occur. The spatial analysis also facilitates easy separation of the aliasing versus non-aliasing regions and angular aliasing removal. Experiments on both synthetic scene and real light field data sets (camera array and Lytro camera) demonstrate that our approach has a number of advantages over the classical prefiltering and depth-dependent light field rendering techniques.

Angular momentum conservation law in light-front quantum field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

Angular momentum conservation law in light-front quantum field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QEDmore » and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

ANGULAR DEPENDENCE OF THE POLARIZATION CORRELATION Cnn AND RECONSTRUCTION OF THE AMPLITUDE MODULI FOR pp SCATTERING AT 640 Mev. ESTIMATION OF THE SINGLET PHASE SHIFTS. PART II (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golovin, B.M.; Dzhelepov, V.P.; Zulkarneev, R.Ya.

1963-01-01

ABS>Experiments on triple scattering of protons are described, and the results of measurement of the spin correlation coefficients C/sub nn/ for 640-Mev protons elastically scattered by protons are presented for a number of angles in the cms which differ from 90 deg . On basis of the experimental data obtained in the presert work and available in the literature, the moduli of the pp-scattering amplitudes are qualitatively determined in a broad angular range 50 deg < yields < 130 deg and their relative contributions are given. The values of the singlet and triplet cross sections for some angles are alsomore » determined. The phase shifts for a pp-system at the indicated energy in singlet states are estimated. (auth)« less

Optimal modeling of 1D azimuth correlations in the context of Bayesian inference

NASA Astrophysics Data System (ADS)

De Kock, Michiel B.; Eggers, Hans C.; Trainor, Thomas A.

2015-09-01

Analysis and interpretation of spectrum and correlation data from high-energy nuclear collisions is currently controversial because two opposing physics narratives derive contradictory implications from the same data, one narrative claiming collision dynamics is dominated by dijet production and projectile-nucleon fragmentation, the other claiming collision dynamics is dominated by a dense, flowing QCD medium. Opposing interpretations seem to be supported by alternative data models, and current model-comparison schemes are unable to distinguish between them. There is clearly need for a convincing new methodology to break the deadlock. In this study we introduce Bayesian inference (BI) methods applied to angular correlation data as a basis to evaluate competing data models. For simplicity the data considered are projections of two-dimensional (2D) angular correlations onto a 1D azimuth from three centrality classes of 200-GeV Au-Au collisions. We consider several data models typical of current model choices, including Fourier series (FS) and a Gaussian plus various combinations of individual cosine components. We evaluate model performance with BI methods and with power-spectrum analysis. We find that FS-only models are rejected in all cases by Bayesian analysis, which always prefers a Gaussian. A cylindrical quadrupole cos(2 ϕ ) is required in some cases but rejected for 0%-5%-central Au-Au collisions. Given a Gaussian centered at the azimuth origin, "higher harmonics" cos(m ϕ ) for m >2 are rejected. A model consisting of Gaussian +dipole cos(ϕ )+quadrupole cos(2 ϕ ) provides good 1D data descriptions in all cases.

The mass and angular momentum of reconstructed metric perturbations

NASA Astrophysics Data System (ADS)

van de Meent, Maarten

2017-06-01

We prove a key result regarding the mass and angular momentum content of linear vacuum perturbations of the Kerr metric obtained through the formalism developed by Chrzarnowski, Cohen, and Kegeles (CCK). More precisely, we prove that the Abbott-Deser mass and angular momentum integrals of any such perturbation vanish when that perturbation was obtained from a regular Fourier mode of the Hertz potential. As a corollary we obtain a generalization of previous results on the completion of the ‘no string’ radiation gauge metric perturbation generated by a point particle. We find that for any bound orbit around a Kerr black hole, the mass and angular momentum perturbations completing the CCK metric are simply the energy and angular momentum of the particle ‘outside’ the orbit and vanish ‘inside’ the orbit.

Measurement of 240Pu Angular Momentum Dependent Fission Probabilities Using the (α ,α') Reaction

NASA Astrophysics Data System (ADS)

Koglin, Johnathon; Burke, Jason; Fisher, Scott; Jovanovic, Igor

2017-09-01

The surrogate reaction method often lacks the theoretical framework and necessary experimental data to constrain models especially when rectifying differences between angular momentum state differences between the desired and surrogate reaction. In this work, dual arrays of silicon telescope particle identification detectors and photovoltaic (solar) cell fission fragment detectors have been used to measure the fission probability of the 240Pu(α ,α' f) reaction - a surrogate for the 239Pu(n , f) - and fission fragment angular distributions. Fission probability measurements were performed at a beam energy of 35.9(2) MeV at eleven scattering angles from 40° to 140°e in 10° intervals and at nuclear excitation energies up to 16 MeV. Fission fragment angular distributions were measured in six bins from 4.5 MeV to 8.0 MeV and fit to expected distributions dependent on the vibrational and rotational excitations at the saddle point. In this way, the contributions to the total fission probability from specific states of K angular momentum projection on the symmetry axis are extracted. A sizable data collection is presented to be considered when constraining microscopic cross section calculations.

Seismic evidence for the loss of stellar angular momentum before the white-dwarf stage.

PubMed

Charpinet, S; Fontaine, G; Brassard, P

2009-09-24

White-dwarf stars represent the final products of the evolution of some 95% of all stars. If stars were to keep their angular momentum throughout their evolution, their white-dwarf descendants, owing to their compact nature, should all rotate relatively rapidly, with typical periods of the order of a few seconds. Observations of their photospheres show, in contrast, that they rotate much more slowly, with periods ranging from hours to tens of years. It is not known, however, whether a white dwarf could 'hide' some of its original angular momentum below the superficial layers, perhaps spinning much more rapidly inside than at its surface. Here we report a determination of the internal rotation profile of a white dwarf using a method based on asteroseismology. We show that the pulsating white dwarf PG 1159-035 rotates as a solid body (encompassing more than 97.5% of its mass) with the relatively long period of 33.61 +/- 0.59 h. This implies that it has lost essentially all of its angular momentum, thus favouring theories which suggest important angular momentum transfer and loss in evolutionary phases before the white-dwarf stage.

Directional view interpolation for compensation of sparse angular sampling in cone-beam CT.

PubMed

Bertram, Matthias; Wiegert, Jens; Schafer, Dirk; Aach, Til; Rose, Georg

2009-07-01

In flat detector cone-beam computed tomography and related applications, sparse angular sampling frequently leads to characteristic streak artifacts. To overcome this problem, it has been suggested to generate additional views by means of interpolation. The practicality of this approach is investigated in combination with a dedicated method for angular interpolation of 3-D sinogram data. For this purpose, a novel dedicated shape-driven directional interpolation algorithm based on a structure tensor approach is developed. Quantitative evaluation shows that this method clearly outperforms conventional scene-based interpolation schemes. Furthermore, the image quality trade-offs associated with the use of interpolated intermediate views are systematically evaluated for simulated and clinical cone-beam computed tomography data sets of the human head. It is found that utilization of directionally interpolated views significantly reduces streak artifacts and noise, at the expense of small introduced image blur.

The angular electronic band structure and free particle model of aromatic molecules: High-frequency photon-induced ring current

NASA Astrophysics Data System (ADS)

Öncan, Mehmet; Koç, Fatih; Şahin, Mehmet; Köksal, Koray

2017-05-01

This work introduces an analysis of the relationship of first-principles calculations based on DFT method with the results of free particle model for ring-shaped aromatic molecules. However, the main aim of the study is to reveal the angular electronic band structure of the ring-shaped molecules. As in the case of spherical molecules such as fullerene, it is possible to observe a parabolic dispersion of electronic states with the variation of angular quantum number in the planar ring-shaped molecules. This work also discusses the transition probabilities between the occupied and virtual states by analyzing the angular electronic band structure and the possibility of ring currents in the case of spin angular momentum (SAM) or orbital angular momentum (OAM) carrying light. Current study focuses on the benzene molecule to obtain its angular electronic band structure. The obtained electronic band structure can be considered as a useful tool to see the transition probabilities between the electronic states and possible contribution of the states to the ring currents. The photoinduced current due to the transfer of SAM into the benzene molecule has been investigated by using analytical calculations within the frame of time-dependent perturbation theory.

The Angular Momentum of Baryons and Dark Matter Halos Revisited

NASA Technical Reports Server (NTRS)

Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

2011-01-01

Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

Novel Detection of Optical Orbital Angular Momentum

DTIC Science & Technology

2014-11-16

spin-orbit coupling at single- photon entanglement and quantum transfer as well as their combinations. Some studies exist on hybrid entanglement . 3.1... Entanglement of the orbital angular momentum states of photons ,” Nature, 412, 313-316 (2001). [9]. D. J. Sanchez and D. W. Oesch, “Orbital angular... photon with no change in its OAM states among traveling inside the atmosphere. Both studies assume only a phase distortion causes by the atmospheric

A systematic construction of microstate geometries with low angular momentum

NASA Astrophysics Data System (ADS)

Bena, Iosif; Heidmann, Pierre; Ramírez, Pedro F.

2017-10-01

We outline a systematic procedure to obtain horizonless microstate geometries that have the same charges as three-charge five-dimensional black holes with a macroscopically-large horizon area and an arbitrarily-small angular momentum. There are two routes through which such solutions can be constructed: using multi-center Gibbons-Hawking (GH) spaces or using superstratum technology. So far the only solutions corre-sponding to microstate geometries for black holes with no angular momentum have been obtained via superstrata [1], and multi-center Gibbons-Hawking spaces have been believed to give rise only to microstate geometries of BMPV black holes with a large angular mo-mentum [2]. We perform a thorough search throughout the parameter space of smooth horizonless solutions with four GH centers and find that these have an angular momentum that is generally larger than 80% of the cosmic censorship bound. However, we find that solutions with three GH centers and one supertube (which are smooth in six-dimensional supergravity) can have an arbitrarily-low angular momentum. Our construction thus gives a recipe to build large classes of microstate geometries for zero-angular-momentum black holes without resorting to superstratum technology.

Linear and angular retroreflecting interferometric alignment target

DOEpatents

Maxey, L. Curtis

2001-01-01

The present invention provides a method and apparatus for measuring both the linear displacement and angular displacement of an object using a linear interferometer system and an optical target comprising a lens, a reflective surface and a retroreflector. The lens, reflecting surface and retroreflector are specifically aligned and fixed in optical connection with one another, creating a single optical target which moves as a unit that provides multi-axis displacement information for the object with which it is associated. This displacement information is useful in many applications including machine tool control systems and laser tracker systems, among others.

A novel upwind stabilized discontinuous finite element angular framework for deterministic dose calculations in magnetic fields.

PubMed

Yang, R; Zelyak, O; Fallone, B G; St-Aubin, J

2018-01-30

Angular discretization impacts nearly every aspect of a deterministic solution to the linear Boltzmann transport equation, especially in the presence of magnetic fields, as modeled by a streaming operator in angle. In this work a novel stabilization treatment of the magnetic field term is developed for an angular finite element discretization on the unit sphere, specifically involving piecewise partitioning of path integrals along curved element edges into uninterrupted segments of incoming and outgoing flux, with outgoing components updated iteratively. Correct order-of-accuracy for this angular framework is verified using the method of manufactured solutions for linear, quadratic, and cubic basis functions in angle. Higher order basis functions were found to reduce the error especially in strong magnetic fields and low density media. We combine an angular finite element mesh respecting octant boundaries on the unit sphere to spatial Cartesian voxel elements to guarantee an unambiguous transport sweep ordering in space. Accuracy for a dosimetrically challenging scenario involving bone and air in the presence of a 1.5 T parallel magnetic field is validated against the Monte Carlo package GEANT4. Accuracy and relative computational efficiency were investigated for various angular discretization parameters. 32 angular elements with quadratic basis functions yielded a reasonable compromise, with gamma passing rates of 99.96% (96.22%) for a 2%/2 mm (1%/1 mm) criterion. A rotational transformation of the spatial calculation geometry is performed to orient an arbitrary magnetic field vector to be along the z-axis, a requirement for a constant azimuthal angular sweep ordering. Working on the unit sphere, we apply the same rotational transformation to the angular domain to align its octants with the rotated Cartesian mesh. Simulating an oblique 1.5 T magnetic field against GEANT4 yielded gamma passing rates of 99.42% (95.45%) for a 2%/2 mm (1%/1 mm) criterion.

A novel upwind stabilized discontinuous finite element angular framework for deterministic dose calculations in magnetic fields

NASA Astrophysics Data System (ADS)

Yang, R.; Zelyak, O.; Fallone, B. G.; St-Aubin, J.

2018-02-01

Angular discretization impacts nearly every aspect of a deterministic solution to the linear Boltzmann transport equation, especially in the presence of magnetic fields, as modeled by a streaming operator in angle. In this work a novel stabilization treatment of the magnetic field term is developed for an angular finite element discretization on the unit sphere, specifically involving piecewise partitioning of path integrals along curved element edges into uninterrupted segments of incoming and outgoing flux, with outgoing components updated iteratively. Correct order-of-accuracy for this angular framework is verified using the method of manufactured solutions for linear, quadratic, and cubic basis functions in angle. Higher order basis functions were found to reduce the error especially in strong magnetic fields and low density media. We combine an angular finite element mesh respecting octant boundaries on the unit sphere to spatial Cartesian voxel elements to guarantee an unambiguous transport sweep ordering in space. Accuracy for a dosimetrically challenging scenario involving bone and air in the presence of a 1.5 T parallel magnetic field is validated against the Monte Carlo package GEANT4. Accuracy and relative computational efficiency were investigated for various angular discretization parameters. 32 angular elements with quadratic basis functions yielded a reasonable compromise, with gamma passing rates of 99.96% (96.22%) for a 2%/2 mm (1%/1 mm) criterion. A rotational transformation of the spatial calculation geometry is performed to orient an arbitrary magnetic field vector to be along the z-axis, a requirement for a constant azimuthal angular sweep ordering. Working on the unit sphere, we apply the same rotational transformation to the angular domain to align its octants with the rotated Cartesian mesh. Simulating an oblique 1.5 T magnetic field against GEANT4 yielded gamma passing rates of 99.42% (95.45%) for a 2%/2 mm (1%/1 mm) criterion.

The maximum vector-angular margin classifier and its fast training on large datasets using a core vector machine.

PubMed

Hu, Wenjun; Chung, Fu-Lai; Wang, Shitong

2012-03-01

Although pattern classification has been extensively studied in the past decades, how to effectively solve the corresponding training on large datasets is a problem that still requires particular attention. Many kernelized classification methods, such as SVM and SVDD, can be formulated as the corresponding quadratic programming (QP) problems, but computing the associated kernel matrices requires O(n2)(or even up to O(n3)) computational complexity, where n is the size of the training patterns, which heavily limits the applicability of these methods for large datasets. In this paper, a new classification method called the maximum vector-angular margin classifier (MAMC) is first proposed based on the vector-angular margin to find an optimal vector c in the pattern feature space, and all the testing patterns can be classified in terms of the maximum vector-angular margin ρ, between the vector c and all the training data points. Accordingly, it is proved that the kernelized MAMC can be equivalently formulated as the kernelized Minimum Enclosing Ball (MEB), which leads to a distinctive merit of MAMC, i.e., it has the flexibility of controlling the sum of support vectors like v-SVC and may be extended to a maximum vector-angular margin core vector machine (MAMCVM) by connecting the core vector machine (CVM) method with MAMC such that the corresponding fast training on large datasets can be effectively achieved. Experimental results on artificial and real datasets are provided to validate the power of the proposed methods. Copyright © 2011 Elsevier Ltd. All rights reserved.

Observations of strong ion-ion correlations in dense plasmas

DOE PAGES

Ma, T.; Fletcher, L.; Pak, A.; ...

2014-04-24

Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ~3× solid density is probed with high-energy photons at 17.9 keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4Å –1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are howevermore » in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. Furthermore, we have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas.« less

A POD reduced order model for resolving angular direction in neutron/photon transport problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchan, A.G., E-mail: andrew.buchan@imperial.ac.uk; Calloo, A.A.; Goffin, M.G.

2015-09-01

This article presents the first Reduced Order Model (ROM) that efficiently resolves the angular dimension of the time independent, mono-energetic Boltzmann Transport Equation (BTE). It is based on Proper Orthogonal Decomposition (POD) and uses the method of snapshots to form optimal basis functions for resolving the direction of particle travel in neutron/photon transport problems. A unique element of this work is that the snapshots are formed from the vector of angular coefficients relating to a high resolution expansion of the BTE's angular dimension. In addition, the individual snapshots are not recorded through time, as in standard POD, but instead theymore » are recorded through space. In essence this work swaps the roles of the dimensions space and time in standard POD methods, with angle and space respectively. It is shown here how the POD model can be formed from the POD basis functions in a highly efficient manner. The model is then applied to two radiation problems; one involving the transport of radiation through a shield and the other through an infinite array of pins. Both problems are selected for their complex angular flux solutions in order to provide an appropriate demonstration of the model's capabilities. It is shown that the POD model can resolve these fluxes efficiently and accurately. In comparison to high resolution models this POD model can reduce the size of a problem by up to two orders of magnitude without compromising accuracy. Solving times are also reduced by similar factors.« less

Correlations in Scattered X-Ray Laser Pulses Reveal Nanoscale Structural Features of Viruses

DOE PAGES

Kurta, Ruslan P.; Donatelli, Jeffrey J.; Yoon, Chun Hong; ...

2017-10-12

We use extremely bright and ultrashort pulses from an x-ray free-electron laser (XFEL) to measure correlations in x rays scattered from individual bioparticles. This allows us to go beyond the traditional crystallography and single-particle imaging approaches for structure investigations. We employ angular correlations to recover the three-dimensional (3D) structure of nanoscale viruses from x-ray diffraction data measured at the Linac Coherent Light Source. Correlations provide us with a comprehensive structural fingerprint of a 3D virus, which we use both for model-based and ab initio structure recovery. The analyses reveal a clear indication that the structure of the viruses deviates frommore » the expected perfect icosahedral symmetry. Lastly, our results anticipate exciting opportunities for XFEL studies of the structure and dynamics of nanoscale objects by means of angular correlations.« less

INTERNAL GRAVITY WAVES IN MASSIVE STARS: ANGULAR MOMENTUM TRANSPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, T. M.; Lin, D. N. C.; McElwaine, J. N.

2013-07-20

We present numerical simulations of internal gravity waves (IGW) in a star with a convective core and extended radiative envelope. We report on amplitudes, spectra, dissipation, and consequent angular momentum transport by such waves. We find that these waves are generated efficiently and transport angular momentum on short timescales over large distances. We show that, as in Earth's atmosphere, IGW drive equatorial flows which change magnitude and direction on short timescales. These results have profound consequences for the observational inferences of massive stars, as well as their long term angular momentum evolution. We suggest IGW angular momentum transport may explainmore » many observational mysteries, such as: the misalignment of hot Jupiters around hot stars, the Be class of stars, Ni enrichment anomalies in massive stars, and the non-synchronous orbits of interacting binaries.« less

Intrinsic alignments in redMaPPer clusters – I. Central galaxy alignments and angular segregation of satellites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Hung -Jin; Mandelbaum, Rachel; Freeman, Peter E.

The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes andmore » the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Lastly, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.« less

Intrinsic alignments in redMaPPer clusters – I. Central galaxy alignments and angular segregation of satellites

DOE PAGES

Huang, Hung -Jin; Mandelbaum, Rachel; Freeman, Peter E.; ...

2016-08-11

The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes andmore » the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Lastly, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.« less

A Methodologic Approach for Normalizing Angular Work and Velocity During Isotonic and Isokinetic Eccentric Training

PubMed Central

Guilhem, Gaël; Cornu, Christophe; Guével, Arnaud

2012-01-01

Context: Resistance exercise training commonly is performed against a constant external load (isotonic) or at a constant velocity (isokinetic). Researchers comparing the effectiveness of isotonic and isokinetic resistance-training protocols need to equalize the mechanical stimulus (work and velocity) applied. Objective: To examine whether the standardization protocol could be adjusted and applied to an eccentric training program. Design: Controlled laboratory study. Setting: Controlled research laboratory. Patients or Other Participants: Twenty-one sport science male students (age = 20.6 ± 1.5 years, height = 178.0 ± 4.0 cm, mass = 74.5 ± 9.1 kg). Intervention(s): Participants performed 9 weeks of isotonic (n = 11) or isokinetic (n = 10) eccentric training of knee extensors that was designed so they would perform the same amount of angular work at the same mean angular velocity. Main Outcome Measure(s): Angular work and angular velocity. Results: The isotonic and isokinetic groups performed the same total amount of work (−185.2 ± 6.5 kJ and −184.4 ± 8.6 kJ, respectively) at the same angular velocity (21 ± 1°/s and 22°/s, respectively) with the same number of repetitions (8.0 and 8.0, respectively). Bland-Altman analysis showed that work (bias = 2.4%) and angular velocity (bias = 0.2%) were equalized over 9 weeks between the modes of training. Conclusions: The procedure developed allows angular work and velocity to be standardized over 9 weeks of isotonic and isokinetic eccentric training of the knee extensors. This method could be useful in future studies in which researchers compare neuromuscular adaptations induced by each type of training mode with respect to rehabilitating patients after musculoskeletal injury. PMID:22488276

Higher order correlations of IRAS galaxies

NASA Technical Reports Server (NTRS)

Meiksin, Avery; Szapudi, Istvan; Szalay, Alexander

1992-01-01

The higher order irreducible angular correlation functions are derived up to the eight-point function, for a sample of 4654 IRAS galaxies, flux-limited at 1.2 Jy in the 60 microns band. The correlations are generally found to be somewhat weaker than those for the optically selected galaxies, consistent with the visual impression of looser clusters in the IRAS sample. It is found that the N-point correlation functions can be expressed as the symmetric sum of products of N - 1 two-point functions, although the correlations above the four-point function are consistent with zero. The coefficients are consistent with the hierarchical clustering scenario as modeled by Hamilton and by Schaeffer.

Gas kinematics, morphology and angular momentum in the FIRE simulations

NASA Astrophysics Data System (ADS)

El-Badry, Kareem; Quataert, Eliot; Wetzel, Andrew; Hopkins, Philip F.; Weisz, Daniel R.; Chan, T. K.; Fitts, Alex; Boylan-Kolchin, Michael; Kereš, Dušan; Faucher-Giguère, Claude-André; Garrison-Kimmel, Shea

2018-01-01

We study the z = 0 gas kinematics, morphology and angular momentum content of isolated galaxies in a suite of cosmological zoom-in simulations from the FIRE project spanning Mstar = 106-11 M⊙. Gas becomes increasingly rotationally supported with increasing galaxy mass. In the lowest mass galaxies (Mstar < 108 M⊙), gas fails to form a morphological disc and is primarily dispersion and pressure supported. At intermediate masses (Mstar = 108-10 M⊙), galaxies display a wide range of gas kinematics and morphologies, from thin, rotating discs to irregular spheroids with negligible net rotation. All the high-mass (Mstar = 1010-11 M⊙) galaxies form rotationally supported gas discs. Many of the haloes whose galaxies fail to form discs harbour high angular momentum gas in their circumgalactic medium. The ratio of the specific angular momentum of gas in the central galaxy to that of the dark matter halo increases significantly with galaxy mass, from 〈jgas〉/〈jDM〉 ∼ 0.1 at M_star=10^{6-7} M_{⊙} to 〈jgas〉/〈jDM〉 ∼ 2 at Mstar = 1010-11 M⊙. The reduced rotational support in the lowest mass galaxies owes to (a) stellar feedback and the UV background suppressing the accretion of high angular momentum gas at late times, and (b) stellar feedback driving large non-circular gas motions. We broadly reproduce the observed scaling relations between galaxy mass, gas rotation velocity, size and angular momentum, but may somewhat underpredict the incidence of disky, high angular momentum galaxies at the lowest observed masses (Mstar = (106-2 × 107) M⊙). Stars form preferentially from low angular momentum gas near the galactic centre and are less rotationally supported than gas. The common assumption that stars follow the same rotation curve as gas thus substantially overestimates the simulated galaxies' stellar angular momentum, particularly at low masses.

Twisted molecular excitons as mediators for changing the angular momentum of light

NASA Astrophysics Data System (ADS)

Zang, Xiaoning; Lusk, Mark T.

2017-07-01

Molecules with CN or CN h symmetry can absorb quanta of optical angular momentum to generate twisted excitons with well-defined quasiangular momenta of their own. Angular momentum is conserved in such interactions at the level of a paraxial approximation for the light beam. A sequence of absorption events can thus be used to create a range of excitonic angular momenta. Subsequent decay can produce radiation with a single angular momentum equal to that accumulated. Such molecules can thus be viewed as mediators for changing the angular momentum of light. This sidesteps the need to exploit nonlinear light-matter interactions based on higher-order susceptibilities. A tight-binding paradigm is used to verify angular momentum conservation and demonstrate how it can be exploited to change the angular momentum of light. The approach is then extended to a time-dependent density functional theory setting where the key results are shown to hold in a many-body, multilevel setting.

Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

NASA Astrophysics Data System (ADS)

Wunderlich, Y.; Afzal, F.; Thiel, A.; Beck, R.

2017-05-01

This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum Lmax needed to achieve a good fit is determined. Then, recent polarization measurements for γ p → π0 p from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel γ p → π0 p, those are the N(1680)5/2+ and Δ(1950)7/2+, contributing to the F-waves.

Helicons in uniform fields. II. Poynting vector and angular momenta

NASA Astrophysics Data System (ADS)

Stenzel, R. L.; Urrutia, J. M.

2018-03-01

The orbital and spin angular momenta of helicon modes have been determined quantitatively from laboratory experiments. The current density is obtained unambiguously from three dimensional magnetic field measurements. The only approximation made is to obtain the electric field from Hall Ohm's law which is usually the case for low frequency whistler modes. This allows the evaluation of the Poynting vector from which the angular momentum is obtained. Comparing two helicon modes (m = 0 and m = 1), one can separate the contribution of angular momentum of a rotating and non-rotating wave field. The orbital angular momentum is important to assess the wave-particle interaction by the transverse Doppler shift of rotating waves which has not been considered so far.

Fabrication of the planar angular rotator using the CMOS process

NASA Astrophysics Data System (ADS)

Dai, Ching-Liang; Chang, Chien-Liu; Chen, Hung-Lin; Chang, Pei-Zen

2002-05-01

In this investigation we propose a novel planar angular rotator fabricated by the conventional complementary metal-oxide semiconductor (CMOS) process. Following the 0.6 μm single poly triple metal (SPTM) CMOS process, the device is completed by a simple maskless, post-process etching step. The rotor of the planar angular rotator rotates around its geometric center with electrostatic actuation. The proposed design adopts an intelligent mechanism including the slider-crank system to permit simultaneous motion. The CMOS planar angular rotator could be driven with driving voltages of around 40 V. The design proposed here has a shorter response time and longer life, without problems of friction and wear, compared to the more common planar angular micromotor.

"Angular" plasma cell cheilitis.

PubMed

da Cunha Filho, Roberto Rheingantz; Tochetto, Lucas Baldissera; Tochetto, Bruno Baldissera; de Almeida, Hiram Larangeira; Lorencette, Nádia Aparecida; Netto, José Fillus

2014-03-17

Plasma cell cheilitis is an extremely rare disease, characterized by erythematous-violaceous, ulcerated and asymptomatic plaques, which evolve slowly. The histological characteristics include dermal infiltrate composed of mature plasmocytes. We report a case of Plasma cell angular cheilitis in a 58-year-old male, localized in the lateral oral commissure.

Mass and angular-momentum inequalities for axi-symmetric initial data sets. II. Angular momentum

NASA Astrophysics Data System (ADS)

Chruściel, Piotr T.; Li, Yanyan; Weinstein, Gilbert

2008-10-01

We extend the validity of Dain's angular-momentum inequality to maximal, asymptotically flat, initial data sets on a simply connected manifold with several asymptotically flat ends which are invariant under a U(1) action and which admit a twist potential.

Achromatic electromagnetic metasurface for generating a vortex wave with orbital angular momentum (OAM).

PubMed

Jiang, Shan; Chen, Chang; Zhang, Hualiang; Chen, Weidong

2018-03-05

The vortex wave that carries orbital angular momentum has attracted much attention due to the fact that it can provide an extra degree of freedom for optical communication, imaging and other applications. In spite of this, the method of OAM generation at high frequency still suffers from limitations, such as chromatic aberration and low efficiency. In this paper, an azimuthally symmetric electromagnetic metasurface with wide bandwidth is designed, fabricated and experimentally demonstrated to efficiently convert a left-handed (right-handed) circularly polarized incident plane wave (with a spin angular momentum (SAM) of ћ) to a right-handed (left-handed) circularly polarized vortex wave with OAM. The design methodology based on the field equivalence principle is discussed in detail. The simulation and measurement results confirm that the proposed method provides an effective way for generating OAM-carrying vortex wave with comparative performance across a broad bandwidth.

Angular radiation models for Earth-atmosphere system. Volume 1: Shortwave radiation

NASA Technical Reports Server (NTRS)

Suttles, J. T.; Green, R. N.; Minnis, P.; Smith, G. L.; Staylor, W. F.; Wielicki, B. A.; Walker, I. J.; Young, D. F.; Taylor, V. R.; Stowe, L. L.

1988-01-01

Presented are shortwave angular radiation models which are required for analysis of satellite measurements of Earth radiation, such as those fro the Earth Radiation Budget Experiment (ERBE). The models consist of both bidirectional and directional parameters. The bidirectional parameters are anisotropic function, standard deviation of mean radiance, and shortwave-longwave radiance correlation coefficient. The directional parameters are mean albedo as a function of Sun zenith angle and mean albedo normalized to overhead Sun. Derivation of these models from the Nimbus 7 ERB (Earth Radiation Budget) and Geostationary Operational Environmental Satellite (GOES) data sets is described. Tabulated values and computer-generated plots are included for the bidirectional and directional modes.

Use of petroleum-based correlations and estimation methods for synthetic fuels

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1980-01-01

Correlations of hydrogen content with aromatics content, heat of combustion, and smoke point are derived for some synthetic fuels prepared from oil and coal syncrudes. Comparing the results of the aromatics content with correlations derived for petroleum fuels shows that the shale-derived fuels fit the petroleum-based correlations, but the coal-derived fuels do not. The correlations derived for heat of combustion and smoke point are comparable to some found for petroleum-based correlations. Calculated values of hydrogen content and of heat of combustion are obtained for the synthetic fuels by use of ASTM estimation methods. Comparisons of the measured and calculated values show biases in the equations that exceed the critical statistics values. Comparison of the measured hydrogen content by the standard ASTM combustion method with that by a nuclear magnetic resonance (NMR) method shows a decided bias. The comparison of the calculated and measured NMR hydrogen contents shows a difference similar to that found with petroleum fuels.

Clustangles: An Open Library for Clustering Angular Data.

PubMed

Sargsyan, Karen; Hua, Yun Hao; Lim, Carmay

2015-08-24

Dihedral angles are good descriptors of the numerous conformations visited by large, flexible systems, but their analysis requires directional statistics. A single package including the various multivariate statistical methods for angular data that accounts for the distinct topology of such data does not exist. Here, we present a lightweight standalone, operating-system independent package called Clustangles to fill this gap. Clustangles will be useful in analyzing the ever-increasing number of structures in the Protein Data Bank and clustering the copious conformations from increasingly long molecular dynamics simulations.

Voronoi Tessellation for reducing the processing time of correlation functions

NASA Astrophysics Data System (ADS)

Cárdenas-Montes, Miguel; Sevilla-Noarbe, Ignacio

2018-01-01

The increase of data volume in Cosmology is motivating the search of new solutions for solving the difficulties associated with the large processing time and precision of calculations. This is specially true in the case of several relevant statistics of the galaxy distribution of the Large Scale Structure of the Universe, namely the two and three point angular correlation functions. For these, the processing time has critically grown with the increase of the size of the data sample. Beyond parallel implementations to overcome the barrier of processing time, space partitioning algorithms are necessary to reduce the computational load. These can delimit the elements involved in the correlation function estimation to those that can potentially contribute to the final result. In this work, Voronoi Tessellation is used to reduce the processing time of the two-point and three-point angular correlation functions. The results of this proof-of-concept show a significant reduction of the processing time when preprocessing the galaxy positions with Voronoi Tessellation.

A promising limited angular computed tomography reconstruction via segmentation based regional enhancement and total variation minimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wenkun; Zhang, Hanming; Li, Lei

2016-08-15

X-ray computed tomography (CT) is a powerful and common inspection technique used for the industrial non-destructive testing. However, large-sized and heavily absorbing objects cause the formation of artifacts because of either the lack of specimen penetration in specific directions or the acquisition of data from only a limited angular range of views. Although the sparse optimization-based methods, such as the total variation (TV) minimization method, can suppress artifacts to some extent, reconstructing the images such that they converge to accurate values remains difficult because of the deficiency in continuous angular data and inconsistency in the projections. To address this problem,more » we use the idea of regional enhancement of the true values and suppression of the illusory artifacts outside the region to develop an efficient iterative algorithm. This algorithm is based on the combination of regional enhancement of the true values and TV minimization for the limited angular reconstruction. In this algorithm, the segmentation approach is introduced to distinguish the regions of different image knowledge and generate the support mask of the image. A new regularization term, which contains the support knowledge to enhance the true values of the image, is incorporated into the objective function. Then, the proposed optimization model is solved by variable splitting and the alternating direction method efficiently. A compensation approach is also designed to extract useful information from the initial projections and thus reduce false segmentation result and correct the segmentation support and the segmented image. The results obtained from comparing both simulation studies and real CT data set reconstructions indicate that the proposed algorithm generates a more accurate image than do the other reconstruction methods. The experimental results show that this algorithm can produce high-quality reconstructed images for the limited angular reconstruction and

A promising limited angular computed tomography reconstruction via segmentation based regional enhancement and total variation minimization

NASA Astrophysics Data System (ADS)

Zhang, Wenkun; Zhang, Hanming; Li, Lei; Wang, Linyuan; Cai, Ailong; Li, Zhongguo; Yan, Bin

2016-08-01

X-ray computed tomography (CT) is a powerful and common inspection technique used for the industrial non-destructive testing. However, large-sized and heavily absorbing objects cause the formation of artifacts because of either the lack of specimen penetration in specific directions or the acquisition of data from only a limited angular range of views. Although the sparse optimization-based methods, such as the total variation (TV) minimization method, can suppress artifacts to some extent, reconstructing the images such that they converge to accurate values remains difficult because of the deficiency in continuous angular data and inconsistency in the projections. To address this problem, we use the idea of regional enhancement of the true values and suppression of the illusory artifacts outside the region to develop an efficient iterative algorithm. This algorithm is based on the combination of regional enhancement of the true values and TV minimization for the limited angular reconstruction. In this algorithm, the segmentation approach is introduced to distinguish the regions of different image knowledge and generate the support mask of the image. A new regularization term, which contains the support knowledge to enhance the true values of the image, is incorporated into the objective function. Then, the proposed optimization model is solved by variable splitting and the alternating direction method efficiently. A compensation approach is also designed to extract useful information from the initial projections and thus reduce false segmentation result and correct the segmentation support and the segmented image. The results obtained from comparing both simulation studies and real CT data set reconstructions indicate that the proposed algorithm generates a more accurate image than do the other reconstruction methods. The experimental results show that this algorithm can produce high-quality reconstructed images for the limited angular reconstruction and suppress

The engagement of optical angular momentum in nanoscale chirality

NASA Astrophysics Data System (ADS)

Andrews, David L.

2017-09-01

Wide-ranging developments in optical angular momentum have recently led to refocused attention on issues of material chirality. The connection between optical spin and circular polarization, linking to well-known and utilized probes of chirality such as circular dichroism, has prompted studies aiming to achieve enhanced means of differentiating enantiomers - molecules or particles of opposite handedness. A number of newly devised schemes for physically separating mirror-image components by optical methods have also been gaining traction, together with a developing appreciation of how the scale of physical dimensions ultimately determines any capacity to differentially select for material chirality. The scope of such enquiries has substantially widened on recognition that suitably structured, topologically charged beams of light - often known as `twisted light' or `optical vortices' can additionally convey orbital angular momentum. A case can be made that understanding the full scope and constraints upon chiroptical interactions in the nanoscale regime involves the resolution of CPT symmetry conditions governing the fundamental interactions between matter and photons. The principles provide a sound theoretical test-bed for new methodologies.

Quaternion-based study of angular velocity of the cardiac vector during myocardial ischaemia.

PubMed

Cruces, Pablo Daniel; Arini, Pedro David

2017-12-01

Early detection of acute ischaemia through non-invasive methods remains a challenge in health research. Ischaemic condition caused by a decrease in the blood supply in a cardiac region induces hypoxia and metabolic abnormalities that contribute to the electrical instability of the heart and to the development of slow conduction in damaged tissue. Herein, a percutaneous transluminal coronary angiography (PTCA) is considered as a model of supply ischaemia. We use the concept of quaternion to develop a robust method for assessing the angular velocity of cardiac vector in the orthogonal XYZ leads obtained from 92 patients undergoing the PTCA procedure. The maxima of angular velocity in both ventricular depolarization and repolarization are combined with traditional linear velocity indexes in order to obtain a detector of ischaemic episodes (Ischaemia Detector, ID). ID achieves 98%/100% of sensitivity/specificity when differentiating healthy subjects from patients with early ischaemia. Furthermore, it also shows high accuracy when the comparison is made between ischaemic subjects and patients with different non-ischaemic pathologic ST-deviations which are known to cause false positives, reaching 95%/98% of sensitivity/specificity. Moreover, the study of significant reductions (p<0.001) of angular velocity components allows extraction of distinct ischaemic common features which are useful for analyzing the dependence of vectorcardiogram signal on each site of occlusion. The sensitivity of injury location reaches values of 88% (RCA), 87% (LAD) and 80% (LCx). The high performance of the proposed method establishes a promising outcome for application in computerized assistance in clinical practice. Copyright © 2017 Elsevier B.V. All rights reserved.

Statistical prescission point model of fission fragment angular distributions

NASA Astrophysics Data System (ADS)

John, Bency; Kataria, S. K.

1998-03-01

In light of recent developments in fission studies such as slow saddle to scission motion and spin equilibration near the scission point, the theory of fission fragment angular distribution is examined and a new statistical prescission point model is developed. The conditional equilibrium of the collective angular bearing modes at the prescission point, which is guided mainly by their relaxation times and population probabilities, is taken into account in the present model. The present model gives a consistent description of the fragment angular and spin distributions for a wide variety of heavy and light ion induced fission reactions.

Control of Angular Intervals for Angle-Multiplexed Holographic Memory

NASA Astrophysics Data System (ADS)

Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki

2009-03-01

In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

Maximal power output by solar cells with angular confinement.

PubMed

Höhn, Oliver; Kraus, Tobias; Bauhuis, Gerard; Schwarz, Ulrich T; Bläsi, Benedikt

2014-05-05

Angularly selective filters can increase the efficiency of radiatively limited solar cells. A restriction of the acceptance angle is linked to the kind of utilizable solar spectrum (global or direct radiation). This has to be considered when calculating the potential enhancement of both the efficiency and the power output. In this paper, different concepts to realize angularly selective filters are compared regarding their limits for efficiency and power output per unit area. First experimental results of a promising system based on a thin-film filter as the angularly selective element are given to demonstrate the practical relevance of such systems.

Compensation for the orbital angular momentum of a vortex beam in turbulent atmosphere by adaptive optics

NASA Astrophysics Data System (ADS)

Li, Nan; Chu, Xiuxiang; Zhang, Pengfei; Feng, Xiaoxing; Fan, ChengYu; Qiao, Chunhong

2018-01-01

A method which can be used to compensate for a distorted orbital angular momentum and wavefront of a beam in atmospheric turbulence, simultaneously, has been proposed. To confirm the validity of the method, an experimental setup for up-link propagation of a vortex beam in a turbulent atmosphere has been simulated. Simulation results show that both of the distorted orbital angular momentum and the distorted wavefront of a beam due to turbulence can be compensated by an adaptive optics system with the help of a cooperative beacon at satellite. However, when the number of the lenslet of wavefront sensor (WFS) and the actuators of the deform mirror (DM) is small, satisfactory results cannot be obtained.

Angular analysis of the B o → K *oμ +μ – decay using 3 fb –1 of integrated luminosity

DOE PAGES

Aaij, R.; Abellán Beteta, C.; Adeva, B.; ...

2016-02-16

An angular analysis of the B o → K *o (→ K +π –)μ +μ – decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb –1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K +π – system in an S-wave configuration. The angular observables and their correlations are reported in bins of q 2, the invariant mass squared of the dimuon system. The observables are determined both from anmore » unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q 2 -dependent decay amplitudes in the region 1.1 < q 2 < 6.0 GeV 2/c 4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions.« less

All joint moments significantly contribute to trunk angular acceleration

PubMed Central

Nott, Cameron R.; Zajac, Felix E.; Neptune, Richard R.; Kautz, Steven A.

2010-01-01

Computationally advanced biomechanical analyses of gait demonstrate the often counter intuitive roles of joint moments on various aspects of gait such as propulsion, swing initiation, and balance. Each joint moment can produce linear and angular acceleration of all body segments (including those on which the moment does not directly act) due to the dynamic coupling inherent in the interconnected musculoskeletal system. This study presents the quantitative relationships between individual joint moments and trunk control with respect to balance during gait to show that the ankle, knee, and hip joint moments all affect the angular acceleration of the trunk. We show that trunk angular acceleration is affected by all the joints in the leg with varying degrees of dependence during the gait cycle. Furthermore, it is shown that inter-planar coupling exists and a two dimensional analysis of trunk balance neglects important out-of-plane joint moments that affect trunk angular acceleration. PMID:20646711

The INCAS Project: An Innovative Contact-Less Angular Sensor

NASA Astrophysics Data System (ADS)

Ghislanzoni, L.; Di Cintio, A.; Solimando, M.; Parzianello, G.

2013-09-01

Angular Positions sensors are widely used in all spacecrafts, including re-entry vehicles and launchers, where mechanisms and pointing-scanning devices are required. The main applications are on mechanisms for TeleMeasure (TM) related to the release and deployment of devices, or on rotary mechanisms such as Solar Array Drive Mechanism (SADM) and Antenna Pointing Mechanism (APM). Longer lifetime (up to 7- 10 years) is becoming a new driver for the coming missions and contact technology sensors often incur in limitations due to the wear of the contacting parts [1].A Self-Compensating Absolute Angular Encoder was developed and tested in the frame of an ESA's ARTES 5.2 project, named INCAS (INnovative Contact-less Angular Sensor). More in particular, the INCAS sensor addresses a market need for contactless angular sensors aimed at replacing the more conventional rotary potentiometers, while featuring the same level of accuracy performances and extending the expected lifetime.

Assessment of digital panoramic radiography's diagnostic value in angular bony lesions with 5 mm or deeper pocket depth in mandibular molars.

PubMed

Saberi, Bardia Vadiati; Nemati, Somayeh; Malekzadeh, Meisam; Javanmard, Afrooz

2017-01-01

Assessment of alveolar bone level in periodontitis is very important in determining prognosis and treatment plan. Panoramic radiography is a diagnostic tool used to screen patients. The aim of the present study was to assess the diagnostic value of digital panoramic radiography in angular bony defects with 5 mm or deeper pocket depth in mandibular molars. In this cross-sectional study, ninety angular bony defects in mandibular molars teeth with 5 mm or deeper pocket depth were selected in sixty patients with the diagnosis of chronic periodontitis. Before surgery, bone probing was performed. During the surgery, the vertical distance from cementoenamel junction to the most apical part of bony defect was measured using a Williams probe and this measurements were employed as gold standard. This distance was measured on the panoramic radiographs by a Digital Calliper and Digital Ruler. All data were compare dusing independent samples t -test and Pearson's correlation coefficient. No significant difference was found between the results of bone probing and intra-surgical measurements ( P = 0.377). The mean defect depth determined by Digital Caliper and Digital Ruler on panoramic radiographs was significantly less than surgical measurements ( P < 0.001). The correlation between bone probing and surgical measurements in determining the defect depth was strong ( r = 0.98, P < 0.001). Radiographic measurements made by Digital Ruler ( r = 0.86), comparing to Digital Caliper ( r = 0.79), showed a higher degree of correlation with surgical measurements. Based on this study, bone probing is a reliable method in vertical alveolar bone defect measurements. While the information obtained from digital panoramic radiographs should be used with caution and the ability of digital panoramic radiography in the determination of defect depth is limited.

Large-angle correlations in the cosmic microwave background

NASA Astrophysics Data System (ADS)

Efstathiou, George; Ma, Yin-Zhe; Hanson, Duncan

2010-10-01

It has been argued recently by Copi et al. 2009 that the lack of large angular correlations of the CMB temperature field provides strong evidence against the standard, statistically isotropic, inflationary Lambda cold dark matter (ΛCDM) cosmology. We compare various estimators of the temperature correlation function showing how they depend on assumptions of statistical isotropy and how they perform on the Wilkinson Microwave Anisotropy Probe (WMAP) 5-yr Internal Linear Combination (ILC) maps with and without a sky cut. We show that the low multipole harmonics that determine the large-scale features of the temperature correlation function can be reconstructed accurately from the data that lie outside the sky cuts. The reconstructions are only weakly dependent on the assumed statistical properties of the temperature field. The temperature correlation functions computed from these reconstructions are in good agreement with those computed from the ILC map over the whole sky. We conclude that the large-scale angular correlation function for our realization of the sky is well determined. A Bayesian analysis of the large-scale correlations is presented, which shows that the data cannot exclude the standard ΛCDM model. We discuss the differences between our results and those of Copi et al. Either there exists a violation of statistical isotropy as claimed by Copi et al., or these authors have overestimated the significance of the discrepancy because of a posteriori choices of estimator, statistic and sky cut.

Angular displacement measuring device

NASA Technical Reports Server (NTRS)

Seegmiller, H. Lee B. (Inventor)

1992-01-01

A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

Gait Phase Recognition for Lower-Limb Exoskeleton with Only Joint Angular Sensors

PubMed Central

Liu, Du-Xin; Wu, Xinyu; Du, Wenbin; Wang, Can; Xu, Tiantian

2016-01-01

Gait phase is widely used for gait trajectory generation, gait control and gait evaluation on lower-limb exoskeletons. So far, a variety of methods have been developed to identify the gait phase for lower-limb exoskeletons. Angular sensors on lower-limb exoskeletons are essential for joint closed-loop controlling; however, other types of sensors, such as plantar pressure, attitude or inertial measurement unit, are not indispensable.Therefore, to make full use of existing sensors, we propose a novel gait phase recognition method for lower-limb exoskeletons using only joint angular sensors. The method consists of two procedures. Firstly, the gait deviation distances during walking are calculated and classified by Fisher’s linear discriminant method, and one gait cycle is divided into eight gait phases. The validity of the classification results is also verified based on large gait samples. Secondly, we build a gait phase recognition model based on multilayer perceptron and train it with the phase-labeled gait data. The experimental result of cross-validation shows that the model has a 94.45% average correct rate of set (CRS) and an 87.22% average correct rate of phase (CRP) on the testing set, and it can predict the gait phase accurately. The novel method avoids installing additional sensors on the exoskeleton or human body and simplifies the sensory system of the lower-limb exoskeleton. PMID:27690023

Three dimensional reliability analyses of currently used methods for assessment of sagittal jaw discrepancy

PubMed Central

Almaqrami, Bushra-Sufyan; Alhammadi, Maged-Sultan

2018-01-01

Background The objective of this study was to analyse three dimensionally the reliability and correlation of angular and linear measurements in assessment of anteroposterior skeletal discrepancy. Material and Methods In this retrospective cross sectional study, a sample of 213 subjects were three-dimensionally analysed from cone-beam computed tomography scans. The sample was divided according to three dimensional measurement of anteroposterior relation (ANB angle) into three groups (skeletal Class I, Class II and Class III). The anterior-posterior cephalometric indicators were measured on volumetric images using Anatomage software (InVivo5.2). These measurements included three angular and seven linear measurements. Cross tabulations were performed to correlate the ANB angle with each method. Intra-class Correlation Coefficient (ICC) test was applied for the difference between the two reliability measurements. P value of < 0.05 was considered significant. Results There was a statistically significant (P<0.05) agreement between all methods used with variability in assessment of different anteroposterior relations. The highest correlation was between ANB and DSOJ (0.913), strong correlation with AB/FH, AB/SN/, MM bisector, AB/PP, Wits appraisal (0.896, 0.890, 0.878, 0.867,and 0.858, respectively), moderate with AD/SN and Beta angle (0.787 and 0.760), and weak correlation with corrected ANB angle (0.550). Conclusions Conjunctive usage of ANB angle with DSOJ, AB/FH, AB/SN/, MM bisector, AB/PP and Wits appraisal in 3D cephalometric analysis provide a more reliable and valid indicator of the skeletal anteroposterior relationship. Clinical relevance: Most of orthodontic literature depends on single method (ANB) with its drawbacks in assessment of skeletal discrepancy which is a cardinal factors for proper treatment planning, this study assessed three dimensionally the degree of correlation between all available methods to make clinical judgement more accurate based on more

Concurrent validation of Xsens MVN measurement of lower limb joint angular kinematics.

PubMed

Zhang, Jun-Tian; Novak, Alison C; Brouwer, Brenda; Li, Qingguo

2013-08-01

This study aims to validate a commercially available inertial sensor based motion capture system, Xsens MVN BIOMECH using its native protocols, against a camera-based motion capture system for the measurement of joint angular kinematics. Performance was evaluated by comparing waveform similarity using range of motion, mean error and a new formulation of the coefficient of multiple correlation (CMC). Three dimensional joint angles of the lower limbs were determined for ten healthy subjects while they performed three daily activities: level walking, stair ascent, and stair descent. Under all three walking conditions, the Xsens system most accurately determined the flexion/extension joint angle (CMC > 0.96) for all joints. The joint angle measurements associated with the other two joint axes had lower correlation including complex CMC values. The poor correlation in the other two joint axes is most likely due to differences in the anatomical frame definition of limb segments used by the Xsens and Optotrak systems. Implementation of a protocol to align these two systems is necessary when comparing joint angle waveforms measured by the Xsens and other motion capture systems.

a Task-Oriented Disaster Information Correlation Method

NASA Astrophysics Data System (ADS)

Linyao, Q.; Zhiqiang, D.; Qing, Z.

2015-07-01

With the rapid development of sensor networks and Earth observation technology, a large quantity of disaster-related data is available, such as remotely sensed data, historic data, case data, simulated data, and disaster products. However, the efficiency of current data management and service systems has become increasingly difficult due to the task variety and heterogeneous data. For emergency task-oriented applications, the data searches primarily rely on artificial experience based on simple metadata indices, the high time consumption and low accuracy of which cannot satisfy the speed and veracity requirements for disaster products. In this paper, a task-oriented correlation method is proposed for efficient disaster data management and intelligent service with the objectives of 1) putting forward disaster task ontology and data ontology to unify the different semantics of multi-source information, 2) identifying the semantic mapping from emergency tasks to multiple data sources on the basis of uniform description in 1), and 3) linking task-related data automatically and calculating the correlation between each data set and a certain task. The method goes beyond traditional static management of disaster data and establishes a basis for intelligent retrieval and active dissemination of disaster information. The case study presented in this paper illustrates the use of the method on an example flood emergency relief task.

Creating fractional quantum Hall states with atomic clusters using light-assisted insertion of angular momentum

NASA Astrophysics Data System (ADS)

Zhang, Junyi; Beugnon, Jerome; Nascimbene, Sylvain

We describe a protocol to prepare clusters of ultracold bosonic atoms in strongly interacting states reminiscent of fractional quantum Hall states. Our scheme consists in injecting a controlled amount of angular momentum to an atomic gas using Raman transitions carrying orbital angular momentum. By injecting one unit of angular momentum per atom, one realizes a single-vortex state, which is well described by mean-field theory for large enough particle numbers. We also present schemes to realize fractional quantum Hall states, namely, the bosonic Laughlin and Moore-Read states. We investigate the requirements for adiabatic nucleation of such topological states, in particular comparing linear Landau-Zener ramps and arbitrary ramps obtained from optimized control methods. We also show that this protocol requires excellent control over the isotropic character of the trapping potential. ERC-Synergy Grant UQUAM, ANR-10-IDEX-0001-02, DIM NanoK Atocirc project.

The ISW effect and the lack of large-angle CMB temperature correlations

NASA Astrophysics Data System (ADS)

Copi, Craig J.; O'Dwyer, Márcio; Starkman, Glenn D.

2016-12-01

It is by now well established that the magnitude of the two-point angular-correlation function of the cosmic microwave background temperature anisotropies is anomalously low for angular separations greater than about 60°. Physics explanations of this anomaly typically focus on the properties of the Universe at the surface of last scattering, relying on the fact that large-angle temperature fluctuations are dominated by the Sachs-Wolfe effect (SW). However, these fluctuations also receive important contributions from the integrated Sachs-Wolfe effect (ISW) at both early (eISW) and late (ℓISW) times. Here, we study the correlations in those large-angle temperature fluctuations and their relative contributions to S1/2- the standard measure of the correlations on large angular scales. We find that in the best-fitting lambda cold dark matter (ΛCDM) cosmology, while the autocorrelation of the early contributions (SW plus eISW) dominates S1/2, there are also significant contributions originating from cross-terms between the early and late contributions. In particular, realizations of ΛCDM with low S1/2 are typically produced from a combination of somewhat low pure-early correlations and accidental cancellations among early-late correlations. We also find that if the pure ℓISW autocorrelations were the only contribution to S1/2 in ΛCDM, then the p-value of the observed cut-sky S1/2 would be unremarkable. This suggests that the physical mechanisms operating only at or near the last scattering surface could explain the observed lack of large-angle correlations, though this is not the typical resolution within ΛCDM.

Assessment of Thematic Mapper Band-to-band Registration by the Block Correlation Method

NASA Technical Reports Server (NTRS)

Card, D. H.; Wrigley, R. C.; Mertz, F. C.; Hall, J. R.

1984-01-01

The design of the Thematic Mapper (TM) multispectral radiometer makes it susceptible to band-to-band misregistration. To estimate band-to-band misregistration a block correlation method is employed. This method is chosen over other possible techniques (band differencing and flickering) because quantitative results are produced. The method correlates rectangular blocks of pixels from one band against blocks centered on identical pixels from a second band. The block pairs are shifted in pixel increments both vertically and horizontally with respect to each other and the correlation coefficient for each shift position is computed. The displacement corresponding to the maximum correlation is taken as the best estimate of registration error for each block pair. Subpixel shifts are estimated by a bi-quadratic interpolation of the correlation values surrounding the maximum correlation. To obtain statistical summaries for each band combination post processing of the block correlation results performed. The method results in estimates of registration error that are consistent with expectations.

On the study of angular velocity in mass asymmetry nuclei

NASA Astrophysics Data System (ADS)

Kaur, Kamaldeep; Kumar, Suneel

2018-05-01

Using isospin-dependent quantum molecular dynamics (IQMD) model, the role of angular velocity (Wy) has been explored by changing the mass asymmetric content of the colliding nuclei at the incident energy of 50 MeV/nucleon for centrality 0.25angular velocity is greatly influenced by the mass-asymmetry as well as by the different rapidity regions. In addition to this, transverse component of angular velocity behaves differently for participant and spectators too.