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Sample records for quasi rotational levels

  1. Application of quasi-degenerate perturbation theory to the calculation of rotational energy levels of methane vibrational polyads

    SciTech Connect

    Cassam-Chenaï, P. Rousseau, G.; Ilmane, A.; Bouret, Y.; Rey, M.

    2015-07-21

    In previous works, we have introduced an alternative perturbation scheme to find approximate solutions of the spectral problem for the rotation-vibration molecular Hamiltonian. An important feature of our approach is that the zero order Hamiltonian is the direct product of a purely vibrational Hamiltonian with the identity on the rotational degrees of freedom. The convergence of our method for the methane vibrational ground state was very satisfactory and our predictions were quantitative. In the present article, we provide further details on the implementation of the method in the degenerate and quasi-degenerate cases. The quasi-degenerate version of the method is tested on excited polyads of methane, and the results are assessed with respect to a variational treatment. The optimal choice of the size of quasi-degenerate spaces is determined by a trade-off between speed of convergence of the perturbation series and the computational effort to obtain the effective super-Hamiltonian.

  2. Dynamics of quasi 2D co-rotating vortex merger

    NASA Astrophysics Data System (ADS)

    Khandekar, Akshay G.

    Merger of vortices is examined experimentally to compare the merger of slender parallel vortices generated coincidentally. It is known that like-sign vortices rotate around a common center of circulation and merger between the vortices may occur under certain conditions. This merger is dependent on the strength of the vortex circulation, distance of separation between the centers of the two vortices, ReGamma, and vorticity distribution. Quasi-2D experimental data is examined and merger relations are derived. The 2D experiments conducted in a vortex generator tank uses high aspect ratio rotating paddles. The vortex merger tank generates slender co-rotating vortices and are examined using PIV (Particle Image Velocimetry). Merger characteristics are compared at centerline, 25% span and 5% span for different circulation strengths. Symmetric and asymmetric mergers are studied and it is found that in both cases, the vortex pair rotates around an axis perpendicular to the plane of the vortex pair. Symmetric merger is seen to occur at the center between the two vortices whereas in asymmetric merger the stronger vortex breaks the weaker vortex filaments and continues to follow its path. Wall effects seem to have an effect of vortex braiding and vortex stretching. Closer to the wall, the merger time increases while the merged vortex dissipates faster than at the centerline.

  3. KIC 10526294: a slowly rotating B star with rotationally split, quasi-equally spaced gravity modes

    NASA Astrophysics Data System (ADS)

    Pápics, P. I.; Moravveji, E.; Aerts, C.; Tkachenko, A.; Triana, S. A.; Bloemen, S.; Southworth, J.

    2014-10-01

    Context. Massive stars are important for the chemical enrichment of the universe. Since internal mixing processes influence their lives, it is very important to place constraints on the corresponding physical parameters, such as core overshooting and the internal rotation profile, so as to calibrate their stellar structure and evolution models. Although asteroseismology has been shown to be able to deliver the most precise constraints so far, the number of detailed seismic studies delivering quantitative results is limited. Aims: Our goal is to extend this limited sample with an in-depth case study and provide a well-constrained set of asteroseismic parameters, contributing to the ongoing mapping efforts of the instability strips of the β Cep and slowly pulsating B (SPB) stars. Methods: We derived fundamental parameters from high-resolution spectra using spectral synthesis techniques. We used custom masks to obtain optimal light curves from the original pixel level data from the Kepler satellite. We used standard time-series analysis tools to construct a set of significant pulsation modes that provide the basis for the seismic analysis carried out afterwards. Results: We find that KIC 10526294 is a cool SPB star, one of the slowest rotators ever found. Despite this, the length of Kepler observations is sufficient to resolve narrow rotationally split multiplets for each of its nineteen quasi-equally spaced dipole modes. The number of detected consecutive (in radial order) dipole modes in this series is higher than ever before. The observed amount of splitting shows an increasing trend towards longer periods, which - largely independent of the seismically calibrated stellar models - points towards a non-rigid internal rotation profile. From the average splitting we deduce a rotation period of ~188 days. From seismic modelling, we find that the star is young with a central hydrogen mass fraction Xc> 0.64; it has a core overshooting αov ≤ 0.15. Based on

  4. Rotation roots and neoclassical viscosity in quasi-symmetry

    NASA Astrophysics Data System (ADS)

    Cole, A. J.; Hegna, C. C.; Callen, J. D.

    2009-11-01

    In a quasi-symmetric device, there exists a symmetry angle αh= θ-Nζ/M, such that |B| = B0(1 - ɛhM αh ) along a field-line, with several much smaller helical `sidebands.' Provided the departure from symmetry is small, i.e. δBeff/B0ɛh where δBeff/B0 is the effective helical sideband strength, flow damping and thus flow evolution along and `cross' the direction of symmetry in a flux surface decouple [1,2], and can be determined successively. In the context of a fluid-moment approach [3], the momentum equation in the symmetry direction is equivalent to the ambipolarity condition. Steady state rotation solutions of this equation are equivalent to ambipolar radial electric field `roots' in conventional stellarator theory and will be presented for various banana-drift neoclassical flow damping regimes [2].[4pt] [1] J. D. Callen, A. J. Cole, and C. C. Hegna, Tech. Rep. UW-CPTC 08-7, Univ. of Wisconsin, http://www.cptc.wisc.edu (2009).[0pt] [2] A. J. Cole, C. C. Hegna, and J. D. Callen, Tech. Rep. UW-CPTC 08-8, Univ. of Wisconsin, http://www.cptc.wisc.edu (2009).[0pt] [3] K. C. Shaing and J. D. Callen, Phys. Fluids 26, 3315 (1983).

  5. Rotation elastogram: a novel method to visualize local rigid body rotation under quasi-static compression

    NASA Astrophysics Data System (ADS)

    Sowmiya, C.; Kothawala, Ali Arshad; Thittai, Arun K.

    2016-04-01

    During manual palpation of breast masses, the perception of its stiffness and slipperiness are the two commonly used information by the physician. In order to reliably and quantitatively obtain this information several non-invasive elastography techniques have been developed that seek to provide an image of the underlying mechanical properties, mostly stiffness-related. Very few approaches have visualized the "slip" at the lesion-background boundary that only occurs for a loosely-bonded benign lesion. It has been shown that axial-shear strain distribution provides information about underlying slip. One such feature, referred to as "fill-in" was interpreted as a surrogate of the rotation undergone by an asymmetrically-oriented-loosely bonded-benign-lesion under quasi-static compression. However, imaging and direct visualization of the rotation itself has not been addressed yet. In order to accomplish this, the quality of lateral displacement estimation needs to be improved. In this simulation study, we utilize spatial compounding approach and assess the feasibility to obtain good quality rotation elastogram. The angular axial and lateral displacement estimates were obtained at different insonification angles from a phantom containing an elliptical inclusion oriented at 45°, subjected to 1% compression from the top. A multilevel 2D-block matching algorithm was used for displacement tracking and 2D-least square compounding of angular axial and lateral displacement estimates was employed. By varying the maximum steering angle and incremental angle, the improvement in the lateral motion tracking accuracy and its effects on the quality of rotational elastogram were evaluated. Results demonstrate significantly-improved rotation elastogram using this technique.

  6. Spectroscopic investigation of the vibrational quasi-continuum arising from internal rotation of a methyl group

    SciTech Connect

    Hougen, J.T.

    1993-12-01

    The goal of this project is to use spectroscopic techniques to investigate in detail phenomena involving the vibrational quasi-continuum in a simple physical system. Acetaldehyde was chosen for the study because: (i) methyl groups have been suggested to be important promotors of intramolecular vibrational relaxation, (ii) the internal rotation of a methyl group is an easily describle large-amplitude motion, which should retain its simple character even at high levels of excitation, and (iii) the aldehyde carbonyl group offers the possibility of both vibrational and electronic probing. The present investigation of the ground electronic state has three parts: (1) understanding the {open_quotes}isolated{close_quotes} internal-rotation motion below, at, and above the top of the torsional barrier, (2) understanding in detail traditional (bond stretching and bending) vibrational fundamental and overtone states, and (3) understanding interactions involving states with multiquantum excitations of at least one of these two kinds of motion.

  7. Neutron scattering observation of quasi-free rotations of water confined in carbon nanotubes

    PubMed Central

    Briganti, G.; Rogati, G.; Parmentier, A.; Maccarini, M.; De Luca, F.

    2017-01-01

    The translational and orientational dynamics of water in carbon nanotubes has been studied by quasi-elastic neutron scattering from 300 down to 10 K. Results show that, reducing temperature below 200 K, part of this water behaves as a quasi-free rotor, that is, the orientational energy of such molecules becomes comparable to the rotational energy of water in the gas phase. This novel and unique dynamic behavior is related to the appearance of water molecules characterized by a coordination number of about two, which is promoted by sub-nanometer axial confinement. This peculiar molecular arrangement allows water to show an active rotational dynamics even at temperatures as low as 10 K. The translational mobility shows a behavior compatible with the rotational one. PMID:28327621

  8. Neutron scattering observation of quasi-free rotations of water confined in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Briganti, G.; Rogati, G.; Parmentier, A.; Maccarini, M.; de Luca, F.

    2017-03-01

    The translational and orientational dynamics of water in carbon nanotubes has been studied by quasi-elastic neutron scattering from 300 down to 10 K. Results show that, reducing temperature below 200 K, part of this water behaves as a quasi-free rotor, that is, the orientational energy of such molecules becomes comparable to the rotational energy of water in the gas phase. This novel and unique dynamic behavior is related to the appearance of water molecules characterized by a coordination number of about two, which is promoted by sub-nanometer axial confinement. This peculiar molecular arrangement allows water to show an active rotational dynamics even at temperatures as low as 10 K. The translational mobility shows a behavior compatible with the rotational one.

  9. Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger

    NASA Astrophysics Data System (ADS)

    Khandekar, Akshay; Jacob, Jamey

    2013-11-01

    Merger of vortices is examined experimentally to compare the merger of slender parallel vortices generated either coincidentally or continuously. It is known that like-sign vortices rotate around a common center of circulation and merger between the vortices may occur under certain conditions. This merger is dependent on the strength of the vortex circulation, distance of separation between the centers of the two vortices, ReΓ , and vorticity distribution. Quasi-2D and 3D experimental data is examined and merger relations are derived. The former uses high aspect ratio rotating paddles in a tank and while the latter are from wing-tip vortices in a wind tunnel. The vortex merger tank generates slender co-rotating vortices and are examined using PIV, while in the wind tunnel two opposing wings are arranged at opposite angles of attack to generate a pair of vortices that merge downstream. A 5-hole probe is used to obtain 3D velocity vectors via wake survey, along with PIV. The procedure is performed in the wake at different distances to observe merger under different conditions. Temporally and spatially dependent relations in quasi-2D and 3D vortex merger are derived. Merger behavior is generally similar between the cases, but instabilities along quasi-2D vortices may affect.

  10. Spin-orbit coupling and chaotic rotation for coorbital bodies in quasi-circular orbits

    SciTech Connect

    Correia, Alexandre C. M.; Robutel, Philippe

    2013-12-10

    Coorbital bodies are observed around the Sun sharing their orbits with the planets, but also in some pairs of satellites around Saturn. The existence of coorbital planets around other stars has also been proposed. For close-in planets and satellites, the rotation slowly evolves due to dissipative tidal effects until some kind of equilibrium is reached. When the orbits are nearly circular, the rotation period is believed to always end synchronous with the orbital period. Here we demonstrate that for coorbital bodies in quasi-circular orbits, stable non-synchronous rotation is possible for a wide range of mass ratios and body shapes. We show the existence of an entirely new family of spin-orbit resonances at the frequencies n ± kν/2, where n is the orbital mean motion, ν the orbital libration frequency, and k an integer. In addition, when the natural rotational libration frequency due to the axial asymmetry, σ, has the same magnitude as ν, the rotation becomes chaotic. Saturn coorbital satellites are synchronous since ν << σ, but coorbital exoplanets may present non-synchronous or chaotic rotation. Our results prove that the spin dynamics of a body cannot be dissociated from its orbital environment. We further anticipate that a similar mechanism may affect the rotation of bodies in any mean-motion resonance.

  11. Quasi-static stop band with flexural metamaterial having zero rotational stiffness

    PubMed Central

    Oh, Joo Hwan; Assouar, Badreddine

    2016-01-01

    Metamaterials realizing stop bands have attracted much attentions recently since they can break-through the well-known mass law. However, achieving the stop band at extremely low frequency has been still a big challenge in the fields of elastic metamaterials. In this paper, we propose a new metamaterial based on the idea of the zero rotational stiffness, to achieve extremely low frequency stop band for flexural elastic waves. Unlike the previous ways to achieve the stop band, we found that the zero rotational stiffness can provide a broad stop band at extremely low frequency, which starts from even almost zero frequency. To achieve the zero rotational stiffness, we propose a new elastic metamaterial consisting of blocks and links with the hinge connection. Analytic developments as well as numerical simulations evidence that this new metamaterial can exhibit extremely low and broad stop band, even at the quasi-static ranges. In addition, the metamaterial is shown to exhibit the negative group velocity at extremely low frequency ranges, as well as the quasi-static stop band, if it is properly designed. PMID:27651146

  12. Quasi-static stop band with flexural metamaterial having zero rotational stiffness.

    PubMed

    Oh, Joo Hwan; Assouar, Badreddine

    2016-09-21

    Metamaterials realizing stop bands have attracted much attentions recently since they can break-through the well-known mass law. However, achieving the stop band at extremely low frequency has been still a big challenge in the fields of elastic metamaterials. In this paper, we propose a new metamaterial based on the idea of the zero rotational stiffness, to achieve extremely low frequency stop band for flexural elastic waves. Unlike the previous ways to achieve the stop band, we found that the zero rotational stiffness can provide a broad stop band at extremely low frequency, which starts from even almost zero frequency. To achieve the zero rotational stiffness, we propose a new elastic metamaterial consisting of blocks and links with the hinge connection. Analytic developments as well as numerical simulations evidence that this new metamaterial can exhibit extremely low and broad stop band, even at the quasi-static ranges. In addition, the metamaterial is shown to exhibit the negative group velocity at extremely low frequency ranges, as well as the quasi-static stop band, if it is properly designed.

  13. Rotating Magnetic Structures Associated with a Quasi-circular Ribbon Flare

    NASA Astrophysics Data System (ADS)

    Li, Haidong; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Hong, Junchao; Bi, Yi

    2017-02-01

    We present the detection of a small eruption and the associated quasi-circular ribbon flare during the emergence of a bipole occurring on 2015 February 3. Under a fan dome, a sigmoid was rooted in a single magnetic bipole, which was encircled by negative polarity. The nonlinear force-free field extrapolation shows the presence of twisted field lines, which can represent a sigmoid structure. The rotation of the magnetic bipole may cause the twisting of magnetic field lines. An initial brightening appeared at one of the footpoints of the sigmoid, where the positive polarity slides toward a nearby negative polarity field region. The sigmoid displayed an ascending motion and then interacted intensively with the spine-like field. This type of null point reconnection in corona led to a violent blowout jet, and a quasi-circular flare ribbon was also produced. The magnetic emergence and rotational motion are the main contributors to the energy buildup for the flare, while the cancellation and collision might act as a trigger.

  14. Quasi four-level Tm:LuAG laser

    NASA Technical Reports Server (NTRS)

    Jani, Mahendra G. (Inventor); Barnes, Norman P. (Inventor); Hutcheson, Ralph L. (Inventor); Rodriguez, Waldo J. (Inventor)

    1997-01-01

    A quasi four-level solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG-based host material doped to a final concentration between about 2% and about 7% thulium (Tm) ions. For the more heavily doped final concentrations, the LuAG-based host material is a LuAG seed crystal doped with a small concentration of Tm ions. Laser diode arrays are disposed transversely to the laser crystal for energizing the Tm ions.

  15. Kinetic theory of quasi-stationary collisionless axisymmetric plasmas in the presence of strong rotation phenomena

    SciTech Connect

    Cremaschini, Claudio; Stuchlík, Zdeněk; Tessarotto, Massimo

    2013-05-15

    The problem of formulating a kinetic treatment for quasi-stationary collisionless plasmas in axisymmetric systems subject to the possibly independent presence of local strong velocity-shear and supersonic rotation velocities is posed. The theory is developed in the framework of the Vlasov-Maxwell description for multi-species non-relativistic plasmas. Applications to astrophysical accretion discs arising around compact objects and to plasmas in laboratory devices are considered. Explicit solutions for the equilibrium kinetic distribution function (KDF) are constructed based on the identification of the relevant particle adiabatic invariants. These are shown to be expressed in terms of generalized non-isotropic Gaussian distributions. A suitable perturbative theory is then developed which allows for the treatment of non-uniform strong velocity-shear/supersonic plasmas. This yields a series representation for the equilibrium KDF in which the leading-order term depends on both a finite set of fluid fields as well as on the gradients of an appropriate rotational frequency. Constitutive equations for the fluid number density, flow velocity, and pressure tensor are explicitly calculated. As a notable outcome, the discovery of a new mechanism for generating temperature and pressure anisotropies is pointed out, which represents a characteristic feature of plasmas considered here. This is shown to arise as a consequence of the canonical momentum conservation and to contribute to the occurrence of temperature anisotropy in combination with the adiabatic conservation of the particle magnetic moment. The physical relevance of the result and the implications of the kinetic solution for the self-generation of quasi-stationary electrostatic and magnetic fields through a kinetic dynamo are discussed.

  16. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2009-04-01

    The QUAGMIRE model has recently been made freely available for public use. QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. This presentation describes the model's main features. QUAGMIRE uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  17. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2009-02-01

    QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. The model uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  18. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2008-09-01

    QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. The model uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  19. Study of the crossing of quasi-energy levels in a four-level system

    SciTech Connect

    Arushanyan, S; Melikyan, A; Saakyan, S

    2011-05-31

    It was shown previously that in taking into account only dipole transitions, the crossing of quasi-energy levels is possible in the system if any of the transitions forms a closed loop. It followed herefrom that for the analysis of the crossing conditions, it is necessary to consider a system which has at least four levels. In this paper we show that we can uniquely specify which quasi-energy levels cross at the given values of the parameters of the atomic system and radiation field, without solving an algebraic quartic equation. It was found that the most suitable system for the implementation of the crossing is the group of energy levels {sup 5}S{sub 1/2}, {sup 5}P{sub 1/2}, {sup 5}P{sub 3/2} and {sup 5}D{sub 3/2} of a rubidium atom. The performed calculations of the laser field intensity and frequency values at which crossing takes place in this system show that they are easily attainable. It turned out that in this system there occur crossing of quasi-energy levels corresponding to the excited atomic levels. (intersection of quasi-energy levels)

  20. Scaling behavior in quasi-geostrophic turbulence in a rotating annulus

    NASA Astrophysics Data System (ADS)

    Swinney, Harry L.; Baroud, Charles N.; Plapp, Brendan B.; She, Zhen-Su

    2001-11-01

    We have made hot film and PIV velocity measurements on turbulent, quasi-two-dimensional flow in a rapidly rotating annulus (Rossby number, 0.05; Reynolds number, 35,000). The flow is driven by pumping fluid into the annulus through a ring of holes near the inner radius and out of the annulus through a ring of holes near the outer radius. The measurements reveal an inverse cascade with E(k) ~ k-2 rather than the expected E(k) ~ k-5/3. The probability distribution functions for longitudinal velocity differences, δ v(l) = v(x+l)-v(x), are self-similar (scale independent) but strongly non-Gaussian. The velocity field images obtained in the PIV measurements suggest that the large coherent vortices play a significant role. The structure functions, <[δ v(l)]^p> ~ r^ζ_p, are characterized by exponents ζp that vary linearly with p, as expected for a self-similar flow. However, the exponents exhibit anomalous scaling, ζ_p=fracp2 rather than ζ_p=fracp3 as in the 1941 Kolmogorov theory.

  1. QSONIC- FULL POTENTIAL TRANSONIC, QUASI-THREE DIMENSIONAL FLOW THROUGH A ROTATING TURBOMACHINERY BLADE ROW

    NASA Technical Reports Server (NTRS)

    Farrell, C. A.

    1994-01-01

    A computer program, QSONIC, has been developed for calculating the full potential, transonic quasi-three-dimensional flow through a rotating turbomachinery blade row. The need for lighter, more efficient turbomachinery components has led to the consideration of machines with fewer stages, each with blades capable of higher speeds and higher loading. As speeds increase, the numerical problems inherent in the transonic regime have to be resolved. These problems include the calculation of imbedded shock discontinuities and the dual nature of the governing equations, which are elliptic in the subcritical flow regions but become hyperbolic for supersonic zones. QSONIC provides the flow analyst with a fast and reliable means of obtaining the transonic potential flow distribution on a blade-to-blade stream surface of a stationary or rotating turbomachine blade row. QSONIC combines several promising transonic analysis techniques. The full potential equation in conservative form is discretized at each point on a body-fitted period mesh. A mass balance is calculated through the finite volume surrounding each point. Each local volume is corrected in the third dimension for any change in stream-tube thickness along the stream tube. The nonlinear equations for all volumes are of mixed type (elliptic or hyperbolic) depending on the local Mach number. The final result is a block-tridiagonal matrix formulation involving potential corrections at each grid point as the unknowns. The residual of each system of equations is solved along each grid line. At points where the Mach number exceeds unity, the density at the forward (sweeping) edge of the volume is replaced by an artificial density. This method calculates the flow field about a cascade of arbitrary two-dimensional airfoils. Three-dimensional flow is approximated in a turbomachinery blade row by correcting for stream-tube convergence and radius change in the through flow direction. Several significant assumptions were made in

  2. Multiple Quasi-Equilibria of the ITCZ and the Origin of Monsoon Onset. Part 2; Rotational ITCZ Attractors

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Chao's numerical and theoretical work on multiple quasi-equilibria of the intertropical convergence zone (ITCZ) and the origin of monsoon onset is extended to solve two additional puzzles. One is the highly nonlinear dependence on latitude of the "force" acting on the ITCZ due to earth's rotation, which makes the multiple quasi-equilibria of the ITCZ and monsoon onset possible. The other is the dramatic difference in such dependence when different cumulus parameterization schemes are used in a model. Such a difference can lead to a switch between a single ITCZ at the equator and a double ITCZ, when a different cumulus parameterization scheme is used. Sometimes one of the double ITCZ can diminish and only the other remain, but still this can mean different latitudinal locations for the single ITCZ. A single idea based on two off-equator attractors for the ITCZ, due to earth's rotation and symmetric with respect to the equator, and the dependence of the strength and size of these attractors on the cumulus parameterization scheme solves both puzzles. The origin of these rotational attractors, explained in Part I, is further discussed. The "force" acting on the ITCZ due to earth's rotation is the sum of the "forces" of the two attractors. Each attractor exerts on the ITCZ a "force" of simple shape in latitude; but the sum gives a shape highly varying in latitude. Also the strength and the domain of influence of each attractor vary, when change is made in the cumulus parameterization. This gives rise to the high sensitivity of the "force" shape to cumulus parameterization. Numerical results, of experiments using Goddard's GEOS general circulation model, supporting this idea are presented. It is also found that the model results are sensitive to changes outside of the cumulus parameterization. The significance of this study to El Nino forecast and to tropical forecast in general is discussed.

  3. Translational and rotational dynamics of water contained in aged Portland cement pastes studied by quasi-elastic neutron scattering.

    PubMed

    Li, Hua; Zhang, Li-Li; Yi, Zhou; Fratini, Emiliano; Baglioni, Piero; Chen, Sow-Hsin

    2015-08-15

    Cement is a widely used construction material in the world. The quality and durability of aged cement pastes have a strong relationship with the water contained in it. The translational and rotational dynamics of water in ordinary Portland cement (OPC) pastes cured for 7, 14 and 30days were studied by analyzing Quasi-elastic Neutron Scattering (QENS) data. The effect of a new super-plasticizer (SP) additive was also studied by comparing the samples with and without the additive. By fitting the QENS spectra with the Jump-diffusion and Rotation-diffusion Model (JRM), six important parameters including the bound water index (BWI), the self-diffusion coefficient, D(t), the average residence time, τ0, the rotational diffusion constant, D(r), the rotational residence time, τ(r), and the mean squared displacement (MSD), 〈u(2)〉, were obtained. From these parameters, we can quantitatively follow the evolution of the bound water fraction (BWI). We can clearly see the different time ranges for the translational and rotational dynamics of water contained in the OPC pastes by τ0 and τ(r). From the MSD values compared with those of molecular dynamics simulation, we can distinguish between immobile water (mainly bound water) and mobile water, which includes confined water and ultraconfined water. Furthermore, by the fitted parameters' values and their change of slopes with increasing setting time for cement pastes with and without additive SP, it becomes clear that the effect of additive SP is to make the mobile water more confined and induce a more uniform the aging process during the evolution of the OPC pastes.

  4. Path integral molecular dynamics simulation of quasi-free rotational motion of CO doped in a large para-hydrogen cluster

    NASA Astrophysics Data System (ADS)

    Mizumoto, Yoshihiko; Ohtsuki, Yukiyoshi

    2011-01-01

    Path integral molecular dynamics simulation is used to study the rotational motion of a CO molecule doped in a large para-hydrogen (p-H2) cluster. The quasi-free rotational motion of CO in a p-H2 cluster with a reduced rotational constant is derived from the imaginary-time orientational correlation functions, and is in good agreement with recent experimental observations. We attribute the reduced rotational constant to the low-viscous fluid-like behavior of the host p-H2 cluster.

  5. Common oscillations in Global Earth Temperature, Sea Level, and Earth rotation

    NASA Astrophysics Data System (ADS)

    Zotov, Leonid; Bizouard, Christian; Sidorenkov, Nikolay

    2014-05-01

    Singular Spectrum Analysis (SSA) of Global Mean Sea Level (GMSL) and Global Average Earth Temperature (HadCRUT4) data after global warming trends subtraction revealed presence of quasi-periodic components with periods of 60, 20 and 10 years in both time series. 60-year component of sea level is anticorrelated with long-periodic changes in temperature, while 10 and 20-year components are correlated. Simultaneous presence of 60-year component in secular Earth rotation rate changes rises a question of interrelations between Earth rotation and Climate. Quasi-20-year changes in GMSL and HadCRUT4 have maxima and minima well corresponding to the amplitude changes of recently reconstructed Chandler wobble excitation, which could be caused by the 18.6-year cycle of the Moon orbital nodes regression. The cause of 10-year oscillations in climate characteristics is enigmatic. It could be related to El Nino variability, Volcanoes, or Solar activity, but correlation with each of those processes found to be small. Looks like it is correlated with 9.3 yr tidal wave.

  6. Effect of upstream rotational field on the formation of magnetic depressions in a quasi-perpendicular shock downstream

    NASA Astrophysics Data System (ADS)

    Tsubouchi, K.; Matsumoto, H.

    2005-04-01

    One-dimensional hybrid simulations are performed to investigate the interaction between an interplanetary rotational magnetic field (RF) and the terrestrial bow shock (a quasi-perpendicular and supercritical regime). A magnetic depression structure called a transient density event (TDE) that is anticorrelated to the density peak is built up and is enlarged from the RF region after its entry into the magnetosheath. Contrary to the MHD view, in which such a diamagnetic structure is sandwiched by two slow or time-dependent intermediate shocks, the TDE generation mechanism is strongly associated with effects of particle kinetics. Within the TDE, the proton temperature parallel to the ambient magnetic field Tp∥ increases to be isotropic, while the ordinary shock downstream consists of strong anisotropic protons (Tp⊥/Tp∥ > 1). This parallel heating is due to enforced conversion of the perpendicular proton motion into a parallel one by the imposed RF. The resultant intense parallel/antiparallel flows generate the field gradient at the leading and trailing edges, which act as a mirror force and reduce the magnetic intensity. In this kinetic sense, slow or Alfvén modes predicted by MHD theories are inadequate for regarding as edges of such a structure. Similar to the normal mirror mode process, particles are concentrated and trapped within the weak field region, leading to a density buildup. The trapped particles lose their energy and undergo cooling as they are bounced at the diverging mirror points. Accordingly, the TDE structure hardly collapses and endures through the magnetosheath. Compared with the mirror instability, isotropization forced by external field fluctuations works more efficiently to produce such a magnetic depression. Thus the presence of the quasi-perpendicular shock, where large temperature anisotropy is generated, is one of the suitable situations for the TDE when interaction with the rotational field has taken place. This interaction model may

  7. Modeling and optimization of actively Q-switched Nd-doped quasi-three-level laser

    NASA Astrophysics Data System (ADS)

    Yan, Renpeng; Yu, Xin; Li, Xudong; Chen, Deying; Gao, Jing

    2013-09-01

    The energy transfer upconversion and the ground state absorption are considered in solving the rate equations for an active Q-switched quasi-three-level laser. The dependence of output pulse characters on the laser parameters is investigated by solving the rate equations. The influence of the energy transfer upconversion on the pulsed laser performance is illustrated and discussed. By this model, the optimal parameters could be achieved for arbitrary quasi-three-level Q-switched lasers. An acousto-optical Q-switched Nd:YAG 946 nm laser is constructed and the reliability of the theoretical model is demonstrated.

  8. An inverse inviscid method for the design of quasi-three dimensional rotating turbomachinery cascades

    NASA Technical Reports Server (NTRS)

    Bonataki, E.; Chaviaropoulos, P.; Papailiou, K. D.

    1991-01-01

    A new inverse inviscid method suitable for the design of rotating blade sections lying on an arbitrary axisymmetric stream-surface with varying streamtube width is presented. The geometry of the axisymmetric stream-surface and the streamtube width variation with meridional distance, the number of blades, the inlet flow conditions, the rotational speed and the suction and pressure side velocity distributions as functions of the normalized arc-length are given. The flow is considered irrotational in the absolute frame of reference and compressible. The output of the computation is the blade section that satisfies the above data. The method solves the flow equations on a (phi 1, psi) potential function-streamfunction plane for the velocity modulus, W and the flow angle beta; the blade section shape can then be obtained as part of the physical plane geometry by integrating the flow angle distribution along streamlines. The (phi 1, psi) plane is defined so that the monotonic behavior of the potential function is guaranteed, even in cases with high peripheral velocities. The method is validated on a rotating turbine case and used to design new blades. To obtain a closed blade, a set of closure conditions were developed and referred.

  9. Effects of propeller rotation direction on airplane interior noise levels

    NASA Technical Reports Server (NTRS)

    Willis, C. M.; Mayes, W. H.; Daniels, E. F.

    1985-01-01

    Interior noise measurements for upsweeping and downsweeping movement of the propeller blade tips past the fuselage were made on a twin-engine airplane and on two simplified fuselage models. Changes in interior noise levels of as much as 8 dB reversal of propeller rotation direction were measured for some configurations and test conditions.

  10. Quasi-elastic light-scattering spectra of swimming spermatozoa. Rotational and translational effects.

    PubMed Central

    Craig, T; Hallett, F R; Nickel, B

    1979-01-01

    The electric field autocorrelation functions of light scattered from normal swimming bull spermatozoa are shown to be dependent on the mean head rotation frequency and not on the translational speed of the cells, as previously believed. This result was obtained from numerical generation of functions in which spermatozoa were modeled as Rayleigh-Gans-Debye ellipsoids having semiaxes a = 0.5 micrometer, b = 2.3 micrometer, and c = 9.0 micrometer. The magnitude of c required to achieve agreement with the experimental data is larger than the half-length of the head region of the cell. This implies that the midpiece, which also lies along c, contributes to the scattering power. Details regarding swimming trajectory and head orientation are included in the model. Analyses of the calculated functions and comparisons with experimentally determined ones suggest that at a scattering angle of 15 degrees the electric field autocorrelation function can be fit a simple Lorentzian whose half-width is inversely proportional to the scattering vector and the mean head rotational frequency. PMID:262561

  11. Rotational Energies in Various Torsional Levels of CH_2DOH

    NASA Astrophysics Data System (ADS)

    Coudert, L. H.; Hilali, A. El; Margulès, L.; Motiyenko, R. A.; Klee, S.

    2012-06-01

    Using an approach accounting for the hindered internal rotation of a monodeuterated methyl group, an analysis of the torsional spectrum of the monodeuterated species of methanol CH_2DOH has been carried out recently and led to the assignment of 76 torsional subbands in its microwave, FIR, and IR spectra. Although this approach also allowed us to account for subband centers, the rotational structure of the torsional subbands is not well understood yet. In this paper, we will deal with the rotational energies of CH_2DOH. Analyses of the rotational structure of the available subbands^b have been performed using the polynomial-type expansion introduced in the case of the normal species of methanol. For each subband, FIR or IR transitions and a-type microwave lines, within the lower torsional level, were fitted. The frequencies of the latters were taken from previous investigations or from new measurements carried out from 50 to 950 GHz with the submillimeterwave solid state spectrometer in Lille. Subbands involving lower levels with v_t=0 and K ≥ 3 could be satisfactorily analyzed. For levels characterized by lower K-values, the expansion fails. In the case of the K=1, v_t=1 level, the frequencies of a-type microwave transitions involving the lower member of the K-type doublet cannot be well reproduced. For K=0 levels with v_t=1 and 2, a large number of terms is needed in the expansion. We will try to understand why the rotational energies of these levels cannot be reproduced. The results of the analyses will be compared to those obtained with a global approach based on the rotation-torsion Hamiltonian of the molecule. [2] El Hilali, Coudert, Konov, and Klee, J. Chem. Phys. 135 (2011) 194309. [3] Ioli, Moruzzi, Riminucci, Strumia, Moraes, Winnewisser, and Winnewisser, J. Mol. Spec. 171 (1995) 130. [4] Quade and Suenram, J. Chem. Phys. 73 (1980) 1127; and Su and Quade, J. Mol. Spec. 134 (1989) 290. [5] Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spec. 256 (2009

  12. Conserved Quantities in General Relativity: From the Quasi-Local Level to Spatial Infinity

    NASA Astrophysics Data System (ADS)

    Chen, Po-Ning; Wang, Mu-Tao; Yau, Shing-Tung

    2015-08-01

    We define quasi-local conserved quantities in general relativity by using the optimal isometric embedding in Wang and Yau (Commun Math Phys 288(3):919-942, 2009) to transplant Killing fields in the Minkowski spacetime back to the 2-surface of interest in a physical spacetime. To each optimal isometric embedding, a dual element of the Lie algebra of the Lorentz group is assigned. Quasi-local angular momentum and quasi-local center of mass correspond to pairing this element with rotation Killing fields and boost Killing fields, respectively. They obey classical transformation laws under the action of the Poincaré group. We further justify these definitions by considering their limits as the total angular momentum and the total center of mass of an isolated system. These expressions were derived from the Hamilton-Jacobi analysis of the gravitational action and thus satisfy conservation laws. As a result, we obtained an invariant total angular momentum theorem in the Kerr spacetime. For a vacuum asymptotically flat initial data set of order 1, it is shown that the limits are always finite without any extra assumptions. We also study these total conserved quantities on a family of asymptotically flat initial data sets evolving by the vacuum Einstein evolution equation. It is shown that the total angular momentum is conserved under the evolution. For the total center of mass, the classical dynamical formula relating the center of mass, energy, and linear momentum is recovered, in the nonlinear context of initial data sets evolving by the vacuum Einstein evolution equation. The definition of quasi-local angular momentum provides an answer to the second problem in classical general relativity on Penrose's list (Proc R Soc Lond Ser A 381(1780):53-63, 1982).

  13. Electron quasi-Fermi level splitting at the base emitter junction of HBTs and DHBTs

    NASA Astrophysics Data System (ADS)

    García-Loureiro, Antonio J.; López-González, Juan M.

    2004-03-01

    In this paper we study the amount of electron quasi-Fermi level splitting in the emitter-base junction of single and double heterojunction bipolar transistors using a new numerical model that includes Fermi-Dirac statistics and base recombination current. The degree of splitting is different using our model than with previous models when high voltage or high doping levels are used. In order to illustrate its features, the model is applied to the study of collector current HBTs and DHBTs.

  14. Paleocene sea level movements with a 430,000 year quasi-periodic cyclicity

    SciTech Connect

    Briskin, M. ); Fluegeman, R. )

    1990-04-01

    Sea level movements with quasi-periodicity of 430,000 years are identified in the marine sedimentary units of the Eastern Gulf Coastal Plain of Mississippi, Alabama and Georgia which represent a 5.8 million year record of strandline displacement during Paleocene time. Principal component analysis of the benthic foraminiferal fauna yielded six assemblages which when combined with two other qualitatively derived assemblages provided paleoecologic information which clearly reflects the influence of paleocirculation and paleoclimatic regime of the Eastern Gulf Coastal Plain. The presence of the planktonic foraminiferal taxa Subbotina trinidadensis and Planorotalites pseudomenardii as well as paleolatitudes ranging from 15{degree} N (for the Campeche Shelf) to 25{degree} N (for the Coastal Plain) emphasizes a paleoclimatic regime which is dominantly tropical. A paleoceanographic model was derived which suggests that normal marine waters were brought into the Gulf of Mexico by two major currents. Strandline displacements are related to transgressive and regressive sea level movements in an ice free Paleocene world. The well delineated 430,000 year quasi-periodic cycle observed in the sea level curve is identified as being astronomical in character. These results support the view that changes in the Earth's orbit may trigger changes in the geometry of the Earth's surface in a way which causes sea level to oscillate with a quasi-periodicity of 430,000 years.

  15. Temperature dependence of quasi-three level laser transition for long pulse Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Pourmand, Seyed Ebrahim; Sidi Ahmad, Muhamad Fakaruddin; Khrisnan, Ganesan; Mohd Taib, Nur Athirah; Nadia Adnan, Nurul; Bakhtiar, Hazri

    2013-02-01

    The influence of temperature and pumping energy on stimulated emission cross section and the laser output of quasi-three level laser transition are reported. Flashlamp is used to pump Nd:YAG laser rod. Distilled water is mixed with ethylene glycol to vary the temperature of the cooling system between -30 and 60 °C. The capacitor voltage of flashlamp driver is verified to manipulate the input energy within the range of 10-70 J. The line of interest in quasi-three level laser comprised of 938.5 and 946 nm. The stimulated emission cross section of both lines is found to be inversely proportional to the temperature but directly proportional to the input energy. This is attributed from thermal broadening effect. The changes of stimulated emission cross section and the output laser with respect to the temperature and input energy on line 946 nm are realized to be more dominant in comparison to 938.5 nm.

  16. Research of quasi-three-level thermal effect of diode-pumped Tm:YAG crystal

    NASA Astrophysics Data System (ADS)

    Niu, Yanxiong; Man, Da; Wang, Caili; Liu, Wenwen; Niu, Haisha

    2014-11-01

    The combination of volumetric heating of the laser material by the absorbed pump radiation and surface cooling required for heat extraction leads to a no uniform temperature distribution in the rod. With the coactions of pump field and coolant, the temperature gradient is formed within laser working medium, and then the thermal effects including thermal lens, thermal stress birefringence, etc. They all seriously restrict the output characteristics of laser. The uniform temperature field distribution in laser working medium weakens the influences of thermal effects in laser. The thermal effect of Tm:YAG laser generated by laser-diode pumping the Tm:YAG crystal is analyzed. After considering the quasi three-level structure of the crystal and the distribution of transmission power in the cavity, a more actual temperature field in the crystal is obtained by revamping the heat conversion coefficient. The thermal effects mechanics were analyzed at first, and then the physical and mathematical thermal analysis models were established based on the theoretical knowledge of thermal effects in LD pumped Tm:YAG laser. The method can be applied to the laser thermal effect research of quasi three-level. The analysis and the result can be referred to the thermal effect research of the solid state laser end-pumped by the LD and the optimal design of resonant cavity.

  17. Point defect reduction in wide bandgap semiconductors by defect quasi Fermi level control

    NASA Astrophysics Data System (ADS)

    Reddy, P.; Hoffmann, M. P.; Kaess, F.; Bryan, Z.; Bryan, I.; Bobea, M.; Klump, A.; Tweedie, J.; Kirste, R.; Mita, S.; Gerhold, M.; Collazo, R.; Sitar, Z.

    2016-11-01

    A theoretical framework for a general approach to reduce point defect density in materials via control of defect quasi Fermi level (dQFL) is presented. The control of dQFL is achieved via excess minority carrier generation. General guidelines for controlling dQFL that lead to a significant reduction in compensating point defects in any doped material is proposed. The framework introduces and incorporates the effects of various factors that control the efficacy of the defect reduction process such as defect level, defect formation energy, bandgap, and excess minority carrier density. Modified formation energy diagrams are proposed, which illustrate the effect of the quasi Fermi level control on the defect formation energies. These formation energy diagrams provide powerful tools to determine the feasibility and requirements to produce the desired reduction in specified point defects. An experimental study of the effect of excess minority carriers on point defect incorporation in GaN and AlGaN shows an excellent quantitative agreement with the theoretical predictions. Illumination at energies larger than the bandgap is employed as a means to generate excess minority carriers. The case studies with CN in Si doped GaN, H and VN in Mg doped GaN and VM-2ON in Si doped Al0.65Ga0.35N revealed a significant reduction in impurities in agreement with the proposed theory. Since compensating point defects control the material performance (this is particularly challenging in wide and ultra wide bandgap materials), dQFL control is a highly promising technique with wide scope and may be utilized to improve the properties of various materials systems and performance of devices based upon them.

  18. Quasi-Periodic Oscillations and Frequencies in AN Accretion Disk and Comparison with the Numerical Results from Non-Rotating Black Hole Computed by the Grh Code

    NASA Astrophysics Data System (ADS)

    Donmez, Orhan

    The shocked wave created on the accretion disk after different physical phenomena (accretion flows with pressure gradients, star-disk interaction etc.) may be responsible observed Quasi Periodic Oscillations (QPOs) in X-ray binaries. We present the set of characteristics frequencies associated with accretion disk around the rotating and non-rotating black holes for one particle case. These persistent frequencies are results of the rotating pattern in an accretion disk. We compare the frequency's from two different numerical results for fluid flow around the non-rotating black hole with one particle case. The numerical results are taken from Refs. 1 and 2 using fully general relativistic hydrodynamical code with non-selfgravitating disk. While the first numerical result has a relativistic tori around the black hole, the second one includes one-armed spiral shock wave produced from star-disk interaction. Some physical modes presented in the QPOs can be excited in numerical simulation of relativistic tori and spiral waves on the accretion disk. The results of these different dynamical structures on the accretion disk responsible for QPOs are discussed in detail.

  19. Effect of gravity level fluctuations for rotating fluids in high and low rotating speeds

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1989-01-01

    Time-dependent evolutions of the profile of the free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with sinusoidal-function vibration of the gravity environment at high and low cylinder speeds.

  20. Quasi-Fermi level splitting and sub-bandgap absorptivity from semiconductor photoluminescence

    SciTech Connect

    Katahara, John K.; Hillhouse, Hugh W.

    2014-11-07

    A unified model for the direct gap absorption coefficient (band-edge and sub-bandgap) is developed that encompasses the functional forms of the Urbach, Thomas-Fermi, screened Thomas-Fermi, and Franz-Keldysh models of sub-bandgap absorption as specific cases. We combine this model of absorption with an occupation-corrected non-equilibrium Planck law for the spontaneous emission of photons to yield a model of photoluminescence (PL) with broad applicability to band-band photoluminescence from intrinsic, heavily doped, and strongly compensated semiconductors. The utility of the model is that it is amenable to full-spectrum fitting of absolute intensity PL data and yields: (1) the quasi-Fermi level splitting, (2) the local lattice temperature, (3) the direct bandgap, (4) the functional form of the sub-bandgap absorption, and (5) the energy broadening parameter (Urbach energy, magnitude of potential fluctuations, etc.). The accuracy of the model is demonstrated by fitting the room temperature PL spectrum of GaAs. It is then applied to Cu(In,Ga)(S,Se){sub 2} (CIGSSe) and Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) to reveal the nature of their tail states. For GaAs, the model fit is excellent, and fitted parameters match literature values for the bandgap (1.42 eV), functional form of the sub-bandgap states (purely Urbach in nature), and energy broadening parameter (Urbach energy of 9.4 meV). For CIGSSe and CZTSSe, the model fits yield quasi-Fermi leveling splittings that match well with the open circuit voltages measured on devices made from the same materials and bandgaps that match well with those extracted from EQE measurements on the devices. The power of the exponential decay of the absorption coefficient into the bandgap is found to be in the range of 1.2 to 1.6, suggesting that tunneling in the presence of local electrostatic potential fluctuations is a dominant factor contributing to the sub-bandgap absorption by either purely electrostatic (screened Thomas-Fermi) or

  1. The influence of solar variability and the quasi-biennial oscillation on sea level pressure

    NASA Astrophysics Data System (ADS)

    Roy, I.; Haigh, J. D.

    2010-12-01

    We investigate an apparent inconsistency between two published results concerning the temperature of the winter polar stratosphere and its dependence on the state of the Sun and the phase of the Quasi-Biennial Oscillation (QBO). We find that the differences can be explained by the use of the authors of different pressure levels to define the phase of the QBO. We identify QBO and solar cycle signals in sea level pressure (SLP) data using a multiple linear regression approach. First we used a standard QBO time series dating back to 1953. In the SLP observations dating back to that time we find at high latitudes that individually the solar and QBO signals are weak but that a temporal index representing the combined effects of the Sun and the QBO shows a significant signal. This is such that combinations of low solar activity with westerly QBO and high solar activity with easterly QBO are both associated with a strengthening in the polar modes; while the opposite combinations coincide with a weakening. This result is true irrespective of the choice of QBO pressure level. By employing a QBO dataset reconstructed back to 1900, we extended the analysis and also find a robust signal in the surface SAM; though weaker for surface NAM. Our results suggest that solar variability, modulated by the phase of QBO, influences zonal mean temperatures at high latitudes in the lower stratosphere and subsequently affect sea level pressure near the poles. Thus a knowledge of the state of the Sun, and the phase of the QBO might be useful in surface climate prediction.

  2. Electric-field-induced destruction of quasi-Landau levels in bilayer graphene nanoribbons.

    PubMed

    Chung, Hsien-Ching; Su, Wu-Pei; Lin, Ming-Fa

    2013-01-21

    The magneto-electronic properties of bilayer zigzag graphene nanoribbons are investigated by the Peierls tight-binding method. In the presence of magnetic fields, Landau quantization leads to the formation of Landau subbands. For the bilayer nanoribbons, these subbands are partially dispersionless in k-space and are called quasi-Landau levels (QLLs). Perpendicular electric fields, serving as the top gate, push the QLLs to higher state energy and split the flat subbands. From the evidence of band structure and density of states, the QLLs remain dispersionless and the corresponding peaks are still the main structure of density of states, which means that the material properties related to the QLLs are unchanged. However, the wave functions present a totally different evidence that the Landau wave functions are severely mixed, and the corresponding material properties would be strongly affected or destroyed. The wave functions provide an effective way to comprehend the characteristics of the flat subbands and Landau subbands. The energy spectra, density of states, and wave functions are discussed in detail.

  3. Fluctuations of the Caspian Sea level in the quasi-two-year and 11-year cycles of solar activity

    SciTech Connect

    Nuzhdina, M.A.

    1995-07-01

    Fluctuations of the Caspian Sea level due to dynamics of solar activity in its quasi-two-year and 11-year cycles, as well as to the influence of the 22-to 23-year magnetic cycle are analyzed. Perturbation of the geomagnetic field and the atmospheric circulation are regarded as a transmitting mechanism of the Sun`s influence on the Earth`s hydrosphere.

  4. Statistical analysis of m/n  =  2/1 locked and quasi-stationary modes with rotating precursors at DIII-D

    NASA Astrophysics Data System (ADS)

    Sweeney, R.; Choi, W.; La Haye, R. J.; Mao, S.; Olofsson, K. E. J.; Volpe, F. A.; The DIII-D Team

    2017-01-01

    A database has been developed to study the evolution, the nonlinear effects on equilibria, and the disruptivity of locked and quasi-stationary modes with poloidal and toroidal mode numbers m  =  2 and n  =  1 at DIII-D. The analysis of 22500 discharges shows that more than 18% of disruptions are due to locked or quasi-stationary modes with rotating precursors (not including born locked modes). A parameter formulated by the plasma internal inductance l i divided by the safety factor at 95% of the poloidal flux, q 95, is found to exhibit predictive capability over whether a locked mode will cause a disruption or not, and does so up to hundreds of milliseconds before the disruption. Within 20 ms of the disruption, the shortest distance between the island separatrix and the unperturbed last closed flux surface, referred to as d edge, performs comparably to {{l}i}/{{q}95} in its ability to discriminate disruptive locked modes. Out of all parameters considered, d edge also correlates best with the duration of the locked mode. Disruptivity following a m/n  =  2/1 locked mode as a function of the normalized beta, {β\\text{N}} , is observed to peak at an intermediate value, and decrease for high values. The decrease is attributed to the correlation between {β\\text{N}} and q 95 in the DIII-D operational space. Within 50 ms of a locked mode disruption, average behavior includes exponential growth of the n  =  1 perturbed field, which might be due to the 2/1 locked mode. Surprisingly, even assuming the aforementioned 2/1 growth, disruptivity following a locked mode shows little dependence on island width up to 20 ms before the disruption. Separately, greater deceleration of the rotating precursor is observed when the wall torque is large. At locking, modes are often observed to align at a particular phase, which is likely related to a residual error field. Timescales associated with the mode evolution are also studied and dictate the

  5. Rotation vibration energy level clustering in the XB1 ground electronic state of PH2

    NASA Astrophysics Data System (ADS)

    Yurchenko, S. N.; Thiel, W.; Jensen, Per; Bunker, P. R.

    2006-10-01

    We use previously determined potential energy surfaces for the Renner-coupled XB1 and AA1 electronic states of the phosphino (PH 2) free radical in a calculation of the energies and wavefunctions of highly excited rotational and vibrational energy levels of the X˜ state. We show how spin-orbit coupling, the Renner effect, rotational excitation, and vibrational excitation affect the clustered energy level patterns that occur. We consider both 4-fold rotational energy level clustering caused by centrifugal distortion, and vibrational energy level pairing caused by local mode behaviour. We also calculate ab initio dipole moment surfaces for the X˜ and A˜ states, and the X˜-A˜ transition moment surface, in order to obtain spectral intensities.

  6. Rotational level involvement in the T1-->S0 intersystem crossing transition in thiophosgene.

    PubMed

    Rashev, Svetoslav; Moule, David C

    2009-04-07

    We propose and develop theoretically a general mechanism for the involvement of rotational motion into the nonradiative transitions that occur in an isolated polyatomic molecule. The treatment is based on the different rotational constants and different (asymmetric top-symmetric top) molecular structures in the two combining electronic states. We focus our attention on the T(1)-->S(0) intersystem crossing (ISC) transition in thiophosgene and show how the rotational mechanism could lead to a considerable enhancement in the effective level density for the process. Inserting the rotational mechanism into our recently developed technique and algorithm for combined spin-orbit coupling+intramolecular vibrational redistribution analysis, we have carried out large-scale calculations that have led to a better understanding of the ISC (T(1)-->S(0)) in thiophosgene.

  7. Comparison of alertness levels in ship crew. An experiment on rotating versus fixed watch schedules.

    PubMed

    Arulanandam, Shalini; Tsing, Gregory Chan Chung

    2009-01-01

    A short pilot study was conducted during a shipboard training deployment to compare alertness levels in the same crew members while working a fixed watch schedule, and then a rotating watch schedule. Alertness levels were assessed before and after each duty watch using measurements of oculomotor function (Fitness Impairment Tester). Saccadic velocity was shown to have the greatest correlation with duration of sleep deprivation and was significantly slower (indicating decreased alertness) in the crew working the rotating watch schedule than the crew working the fixed watch schedule. This pilot study corroborates previous studies' recommendations that fixed watch schedules allow better acclimatization of sleep patterns, thus minimizing fatigue and increasing operational alertness.

  8. Iterative algorithm for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution

    NASA Astrophysics Data System (ADS)

    Quan, Haiyang; Wu, Fan; Hou, Xi

    2015-10-01

    New method for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution is proposed. It is based on basic iterative scheme and accelerates the Gauss-Seidel method by introducing an acceleration parameter. This modified Successive Over-relaxation (SOR) is effective for solving the rotationally asymmetric components with pixel-level spatial resolution, without the usage of a fitting procedure. Compared to the Jacobi and Gauss-Seidel method, the modified SOR method with an optimal relaxation factor converges much faster and saves more computational costs and memory space without reducing accuracy. It has been proved by real experimental results.

  9. Interferometric visualization and demodulation method for measuring quasi-static strain in fiber Bragg grating sensors by a simple rotating etalon filter

    NASA Astrophysics Data System (ADS)

    Rocco, Alessandra S.; Coppola, Giuseppe; Ferraro, Pietro; Foti, Giuseppe; Iodice, Mario

    2004-09-01

    Optical fiber sensors are the ideal system to monitor "smart structures" and on-site/real time stress measurements: they can be in fact easily embedded or attached to the structures under test and are not affected by electro- magnetic noise. In particular a signal from a Fiber Bragg grating sensor (FBG) may be processed such that its information remains immune to optical power fluctuations. Different interrogation methods can be used for reading out Bragg wavelength shifts. In this paper we propose a very simple interferometric method for interrogating FBG sensors, based on bi-polished silicon sample acting like an etalon tuneable filter (ETF). The Bragg wavelength shift can be evaluated by analyzing the spectral response of signal reflected by the FBG sensor and filtered by the ETF that is continuously and rapidly tuned. Tuning was obtained by rotating the ETF. Variation in the strain at the FBG causes a phase shift in the analyzed signal. The overall spectral signal, collected with time, consists in an interferometric figure which finesse and fringe contrast depending on the geometrical sizes and facets reflectivity of the silicon sample. The fringe pattern, expressed by the Airy's formula, depends on the wavelength l of the incident radiation and on the angle of incidence. The phase of fringe pattern can be retrieved by a standard FFT method giving quantitative measurements of the quasi-static strain variation sensed by the FBG. In this way, the method allows a valuable visualization of the time-evolution of the incremental strain applied to the FBG. Principle of functioning of this method is described and first results obtained employing such configuration, are reported.

  10. Influence of energy-transfer-upconversion on threshold pump power in quasi-three-level solid-state lasers.

    PubMed

    Kim, J W; Mackenzie, J I; Clarkson, W A

    2009-07-06

    A simple analytical expression for threshold pump power in an end-pumped quasi-three-level solid-state laser, which takes into account the influence of energy-transfer-upconversion (ETU), is derived. This expression indicates that threshold pump power can be increased dramatically by ETU, especially in low gain lasers and lasers with pronounced three-level character due to the need for high excitation densities in the upper manifold to reach threshold. The analysis has been applied to an Er:YAG laser operating at 1645 nm in-band pumped by an Er,Yb fiber laser at 1532 nm. Predicted values for threshold pump power as a function of erbium doping concentration are in very good agreement with measured values. The results indicate that very low erbium doping levels (approximately 0.25 at.% or less) are required to avoid degradation in performance due to ETU even under continuous-wave lasing conditions in Er:YAG.

  11. Establishing the level of cylindrical rotation in boxy/peanut bulges

    NASA Astrophysics Data System (ADS)

    Molaeinezhad, A.; Falcón-Barroso, J.; Martínez-Valpuesta, I.; Khosroshahi, H. G.; Balcells, M.; Peletier, R. F.

    2016-02-01

    We present SAURON integral-field observations of a sample of 12 mid-to-high-inclination disc galaxies, to unveil hidden bars on the basis of their kinematics, i.e. the correlation between velocity and h3 profiles, and to establish their degree of cylindrical rotation. For the latter, we introduce a method to quantify cylindrical rotation that is robust against inner disc components. We confirm high levels of cylindrical rotation in boxy/peanut bulges, but also observe this feature in a few galaxies with rounder bulges. We suggest that these are also barred galaxies with end-on orientations. Re-analysing published data for our own Galaxy using this new method, we determine that the Milky Way bulge is cylindrically rotating at the same level as the strongest barred galaxy in our sample. Finally, we use self-consistent three-dimensional N-body simulations of bar-unstable discs to study the dependence of cylindrical rotation on the bar's orientation and host galaxy inclination.

  12. Effects of Spatial Ability Levels and Presentation Platform on Performance of a Pictured Rotation Task.

    ERIC Educational Resources Information Center

    Manrique, Fernando; And Others

    This study investigated the effects of two levels of spatial ability--high spatial, low spatial--and two different presentation platforms--virtual reality, computer monitor--on performance of a pictured rotation task over two consecutive trials. Performance was measured by response time and accuracy. The 24 male and 8 female subjects (college…

  13. Vibrational Energy Levels via Finite-Basis Calculations Using a Quasi-Analytic Form of the Kinetic Energy.

    PubMed

    Vázquez, Juana; Harding, Michael E; Stanton, John F; Gauss, Jürgen

    2011-05-10

    A variational method for the calculation of low-lying vibrational energy levels of molecules with small amplitude vibrations is presented. The approach is based on the Watson Hamiltonian in rectilinear normal coordinates and characterized by a quasi-analytic integration over the kinetic energy operator (KEO). The KEO beyond the harmonic approximation is represented by a Taylor series in terms of the rectilinear normal coordinates around the equilibrium configuration. This formulation of the KEO enables its extension to arbitrary order until numerical convergence is reached for those states describing small amplitude motions and suitably represented with a rectilinear system of coordinates. A Gauss-Hermite quadrature grid representation of the anharmonic potential is used for all the benchmark examples presented. Results for a set of molecules with linear and nonlinear configurations, i.e., CO2, H2O, and formyl fluoride (HFCO), illustrate the performance of the method and the versatility of our implementation.

  14. Effect of a uniform sea-level change on the earth's rotation and gravitational field

    NASA Technical Reports Server (NTRS)

    Chao, B. Fong; O'Connor, William P.

    1988-01-01

    Global water redistriburtion between the oceans, atmosphere and continents causes changes in the earth's rotation and gravitational field. To conserve water mass, the effect of the small uniform change in sea-level must be considered. Explicit formulas are provided for these sea-level corrections to the gravitational Stokes coefficients, polar motion and length of day. In two recent publications, this sea-level correction term for polar motion was given incorrectly. These errors which arose from normalization conventions with the ocean function are corrected.

  15. Two-stage double-level rotational osteotomy in the treatment of congenital radioulnar synostosis.

    PubMed

    El-Adl, Wael

    2007-12-01

    Congenital proximal radioulnar synostosis is a rare congenital anomaly that can be extremely disabling, especially when it occurs bilaterally or if there is severe hyperpronation. Currently, osteotomy to achieve a neutral or slightly pronated position is widely accepted for the management of patients who have severe pronation. The present study evaluates the result of two-stage double-level rotational osteotomy of both the radius and ulna in the treatment of severe congenital radioulnar synostosis. Nine children with severe congenital radioulnar synostosis underwent two-stage double-level rotational osteotomy of both the radius and ulna at Mansoura University Hospital. There were seven boys and two girls with a mean age of 5.6 years who were followed up for a mean of 26 months. The position of the forearm was improved from a mean pronation deformity of 76 degrees (60 degrees to 85 degrees) to 30 degrees of pronation in the affected dominant extremities and 20 degrees of supination in non-dominant extremities in all cases. Bony union was achieved by 5.9 weeks with no loss of correction. The advantages of this technique are that it is easy, safe, with absence of severe postoperative complications and requires a small surgical scar. A drawback of the technique is that the rotation correction depends only on a cast, so that a correction loss might occur if the plaster cast loosens.

  16. Ab initio potential energy surface and vibration-rotation energy levels of beryllium monohydroxide.

    PubMed

    Koput, Jacek

    2017-01-05

    The accurate potential energy surface of beryllium monohydroxide, BeOH, in its ground electronic state X 2A' has been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent core-valence basis sets up to septuple-zeta quality. The higher-order electron correlation, scalar relativistic, and adiabatic effects were taken into account. The BeOH molecule was confirmed to be bent at equilibrium, with the BeOH angle of 141.2° and the barrier to linearity of 129 cm(-1) . The vibration-rotation energy levels of the BeOH and BeOD isotopologues were predicted using a variational approach and compared with recent experimental data. The results can be useful in a further analysis of high-resolution vibration-rotation spectra of these interesting species. © 2016 Wiley Periodicals, Inc.

  17. The mixed level damping of the single-axial rotation of INS

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Zhu, Hai; Li, Gang; Gao, Dayuan

    2011-12-01

    In order to improve the accuracy of the Single-axial Rotation of INS (SRINS), the idea of the level damping of the platform INS is introduced to the system, and the principle of the damping is offered. On the basic of analyzing on both of inner level damping and outer level damping, the mixed level damping is put forward. The results show that by introducing the damping network to the system, both of the Schuler oscillation and the Foucault oscillation are eliminated, and the precision of the SRINS is greatly enhanced; At the same time, by used of the mixed level damping, which can not only reduce the effect of the vehicle power-driven to the precision of the system, but also avoid the limit of the accurate reference velocity.

  18. Rotational stress-induced increase in epinephrine levels delays cutaneous wound healing in mice.

    PubMed

    Romana-Souza, Bruna; Otranto, Marcela; Vieira, Andreza M; Filgueiras, Cláudio C; Fierro, Iolanda M; Monte-Alto-Costa, Andréa

    2010-03-01

    Stress impairs wound healing of cutaneous lesions; however, the mechanism is still unclear. The aim of this study was to evaluate the effects of rotational stress on cutaneous wound healing in mice and propose a mechanism. Male mice were spun at 45 rpm for 15 min every hour beginning 3 days before wounding until euthanasia. Control animals were not subjected to stress. To confirm that catecholamines participate in stress-induced delay of wound healing, mice were treated daily with propranolol. An excisional lesion was created and measured. Seven and 14 days later, animals were killed and lesions collected. Sections were stained with hematoxylin-eosin and immunostained for alpha-smooth muscle actin and proliferating cell nuclear antigen. Matrix metalloproteinase (MMP)-2 and -9 activity, nitrite levels, and tumor necrosis factor-alpha (TNF-alpha) expression were measured in the wounds. In addition, murine skin fibroblast cultures were treated with high levels of epinephrine and fibroblast activity was evaluated. Stressed mice exhibited reduced locomotor activity and increased normetanephrine plasma levels. Rotational stress was associated with decreased wound contraction, reduced re-epithelialization, reduced MMP-2 and MMP-9 activation, but with strongly increased nitrite levels. Furthermore, inflammatory cell infiltration, TNF-alpha expression, myofibroblastic differentiation, and angiogenesis were all delayed in the stress group. Propranolol administration reversed the deleterious effects of stress on wound contraction and re-epithelialization. High epinephrine concentrations increased murine skin fibroblast proliferation and nitric oxide synthesis, and strongly inhibited skin fibroblast migration and both pro- and active MMP-2. In conclusion, rotational stress impairs cutaneous wound healing due to epinephrine increased levels.

  19. Characterization of deep level defects present in mono-like, quasi-mono and multicrystalline silicon solar substrates

    NASA Astrophysics Data System (ADS)

    Pérez, E.; García, H.; Castán, H.; Dueñas, S.

    2015-03-01

    Defects on mono-like (ml-Si), quasi-mono (qm-Si) and multicrystalline silicon solar cell substrates are studied in depth. Using the thermal admittance spectroscopy technique we found a single deep level with an activation energy between 213 and 224 meV and a capture cross section in the order of 10-15-10-14 cm2, in the case of ml-Si samples. The 271, 291 and 373 meV levels were found in qm-Si samples. The first one is associated with a capture cross section in the order of 10-16 cm2, the second one in the order of 10-14, while the third one is associated, for the same magnitude, with a value in the order of 10-12 cm2. Multicrystalline samples showed two tendencies in the Arrhenius plot fit associated with a deep level in each one. The activation energy of the first one ranges from 336 meV to 342 meV, and the capture cross sections are in the order of 10-13-10-11 cm2. The values obtained for the second one are 251 and 171 meV, with the capture cross section values in the order of 10-15 and 10-18 cm2, respectively. The nature of these defects is probably due to iron-based impurities in different complexes. Segregation into extended defects of Fei or Fei-V is the most probable cause of the deep levels with higher capture cross section value. Punctual complexes such as Fei or Fei-V2 are probably the reason for the deep levels with lower capture cross section value.

  20. Quasi-periodic, global oscillations in sea level pressure on intraseasonal timescales

    NASA Astrophysics Data System (ADS)

    Kiranmayi, L.; Bhat, G. S.

    2009-06-01

    The sea level pressure (SLP) variability in 30-60 day intraseasonal timescales is investigated using 25 years of reanalysis data addressing two issues. The first concerns the non-zero zonal mean component of SLP near the equator and its meridional connections, and the second concerns the fast eastward propagation (EP) speed of SLP compared to that of zonal wind. It is shown that the entire globe resonates with high amplitude wave activity during some periods which may last for few to several months, followed by lull periods of varying duration. SLP variations in the tropical belt are highly coherent from 25°S to 25°N, uncorrelated with variations in mid latitudes and again significantly correlated but with opposite phase around 60°S and 65°N. Near the equator (8°S-8°N), the zonal mean contributes significantly to the total variance in SLP, and after its removal, SLP shows a dominant zonal wavenumber one structure having a periodicity of 40 days and EP speeds comparable to that of zonal winds in the Indian Ocean. SLP from many of the atmospheric and coupled general circulation models show similar behaviour in the meridional direction although their propagation characteristics in the tropical belt differ widely.

  1. The Response of Ceramic Powders to High-Level Quasi-Isentropic Dynamic Loads

    NASA Astrophysics Data System (ADS)

    Lawrence, R. J.; Grady, D. E.; Hall, C. A.

    2004-07-01

    The pulsed-power Z machine, in an isentropic compression experiment (ICE) mode, will allow the dynamic characterization of porous materials—here various ceramic powders, e.g., Al2O3, WC, ZrO2—at roughly half their solid densities. A cylindrical configuration can provide megabar-level loads on an annulus of the sample material. Data will be provided by velocity interferometers that measure free-surface (or possibly interface) particle velocities. Differing sample thicknesses using stepped or conical geometries yield experimental efficiency by allowing multiple data records on single shots. With the p/α model for porous materials, the one-dimensional Lagrangian hydrocode WONDY provides the needed analyses. Based on static data, both power-law and quadratic crush curves are employed. Within the model constraints, we suggest that the most important parameter for characterizing the material is the crush strength, ps. With adequate sample thicknesses, the planned velocity measurements differentiate among the various assumptions for ps.

  2. Reverse engineering of a Hamiltonian for a three-level system via the Rodrigues’ rotation formula

    NASA Astrophysics Data System (ADS)

    Kang, Yi-Hao; Huang, Bi-Hua; Lu, Pei-Min; Xia, Yan

    2017-02-01

    We propose a scheme to reversely construct a three-level Hamiltonian via the Rodrigues’ rotation formula and an auxiliary unitary transformation. The main goal of the scheme is designing feasible pulses to drive a three-level system to evolve rapidly from an arbitrary initial state to a desired final state. Numerical simulations demonstrate that the scheme is not only fast but also robust against the decoherence caused by fluctuations of control parameters and some dissipation factors. Besides, we apply the idea to implement a Hadamard gate in a three-level system, and the results show the present scheme is much faster compared with stimulated Raman adiabatic passage (STIRAP). Therefore, the scheme may be useful to find out an effective shortcut to the adiabatic passage in a three-level system.

  3. Comprehension and Motivation Levels in Conjunction with the Use of eBooks with Audio: A Quasi-Experimental Study of Post-Secondary Remedial Reading Students

    ERIC Educational Resources Information Center

    Wheeler, Kimberly W.

    2014-01-01

    This quasi-experimental pretest, posttest nonequivalent control group study investigated the comprehension scores and motivation levels of post-secondary remedial reading students in a two-year technical college in Northwest Georgia using an eBook, an eBook with audio, and a print book. After reading a module on Purpose and Tone in the three book…

  4. Zeeman-tuned rotational level-crossing spectroscopy in a diatomic free radical.

    PubMed

    Cahn, S B; Ammon, J; Kirilov, E; Gurevich, Y V; Murphree, D; Paolino, R; Rahmlow, D A; Kozlov, M G; DeMille, D

    2014-04-25

    Rotational levels of molecular free radicals can be tuned to degeneracy by using laboratory-scale magnetic fields. Because of their intrinsically narrow width, these level crossings of opposite-parity states have been proposed for use in the study of parity-violating interactions and other applications. We experimentally study a typical manifestation of this system using BaF138. Using a Stark-mixing method for detection, we demonstrate level-crossing signals with spectral width as small as 6 kHz. We use our data to verify the predicted line shapes, transition dipole moments, and Stark shifts and to precisely determine molecular magnetic g factors. Our results constitute an initial proof of concept for use of this system to study nuclear spin-dependent parity-violating effects.

  5. Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues

    NASA Astrophysics Data System (ADS)

    Astashkevich, S. A.; Lavrov, B. P.

    2015-06-01

    The current situation in studies of lifetimes of excited rovibronic levels for the H2, D2, T2, HD, HT, and DT molecules is analyzed. All measured lifetime values (792 entries for 618 different vibro-rotational levels of 33 electronic states) reported in 61 publications before April 2015 are compiled and listed in tabular format together with an annotated bibliography. Experimental data are only available for the H2, HD, and D2 molecules. The data collected in the present work show fragmentariness of experimental data. For the vast majority of the levels, the lifetime values were reported in one paper only and up to now are without independent experimental verification. A complete bibliography of publications concerning semiempirical determination and nonempirical calculations of the lifetimes is presented. Numerical results obtained in the framework of these two approaches are listed only in cases when experimental data are available. For more than half of the levels, the differences between measured and calculated values are three times higher than experimental errors. These discrepancies show necessity of more precise experimental and nonempirical studies. For some 79 rovibronic levels, our analysis makes it possible to propose certain set of recommended lifetime values.

  6. Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues

    SciTech Connect

    Astashkevich, S. A. Lavrov, B. P.

    2015-06-15

    The current situation in studies of lifetimes of excited rovibronic levels for the H{sub 2}, D{sub 2}, T{sub 2}, HD, HT, and DT molecules is analyzed. All measured lifetime values (792 entries for 618 different vibro-rotational levels of 33 electronic states) reported in 61 publications before April 2015 are compiled and listed in tabular format together with an annotated bibliography. Experimental data are only available for the H{sub 2}, HD, and D{sub 2} molecules. The data collected in the present work show fragmentariness of experimental data. For the vast majority of the levels, the lifetime values were reported in one paper only and up to now are without independent experimental verification. A complete bibliography of publications concerning semiempirical determination and nonempirical calculations of the lifetimes is presented. Numerical results obtained in the framework of these two approaches are listed only in cases when experimental data are available. For more than half of the levels, the differences between measured and calculated values are three times higher than experimental errors. These discrepancies show necessity of more precise experimental and nonempirical studies. For some 79 rovibronic levels, our analysis makes it possible to propose certain set of recommended lifetime values.

  7. Precision measurement of the rotational energy-level structure of the three-electron molecule He2+

    NASA Astrophysics Data System (ADS)

    Semeria, Luca; Jansen, Paul; Merkt, Frédéric

    2016-11-01

    The term values of all rotational levels of the 4 He 2 + X + 2 Σu + ( ν + = 0 ) ground vibronic state with rotational quantum number N+ ≤ 19 have been determined with an accuracy of 8 × 10-4 cm-1 (˜25 MHz) by multichannel-quantum-defect-theory-assisted Rydberg spectroscopy of metastable He 2∗ . Comparison of these term values with term values recently calculated ab initio by Tung et al. [J. Chem. Phys. 136, 104309 (2012)] reveals discrepancies that rapidly increase with increasing rotational quantum number and reach values of 0.07 cm-1 (˜2.1 GHz) at N+ = 19.

  8. Ab initio potential energy surface and vibration-rotation energy levels of sulfur dioxide.

    PubMed

    Koput, Jacek

    2017-05-05

    An accurate potential energy surface of sulfur dioxide, SO2 , in its ground electronic state X∼ 1A1 has been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent basis sets up to septuple-zeta quality. The results obtained with the conventional and explicitly correlated coupled-cluster methods are compared. The role of the core-electron correlation, higher-order valence-electron correlation, scalar relativistic, and adiabatic effects in determining the structure and dynamics of the SO2 molecule is discussed. The vibration-rotation energy levels of the (32) SO2 and (34) SO2 isotopologues were predicted using a variational approach. It was shown that the inclusion of the aforementioned effects was mandatory to attain the "spectroscopic" accuracy. © 2017 Wiley Periodicals, Inc.

  9. Theoretical and experimental study on reabsorption effect and temperature characteristic of a quasi-three-level 946nm Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Huang, Jing; Wan, Yuan; Chen, Weibiao

    2015-02-01

    The influence of temperature and incident pump power on reabsorption loss is theoretically discussed. Temperature characteristic and reabsorption loss rate of a diode-pumped quasi-three-level 946 nm Nd:YAG laser are investigated. Reabsorption effect has a significant impact on laser performance. The results indicate that reabsorption loss increases as the working temperature rises and decreases with the increased incident pump power.

  10. Optimization of the levels of grip force, stroke rotation, frequency and grip span for a torqueing task.

    PubMed

    Bano, Farheen; Mallick, Zulqernian; Ali Khan, Abid

    2015-01-01

    This study was to investigate the effects of grip force, frequency, stroke rotation and grip-span on discomfort and obtain best posture for hand tool users. Fifteen male participants volunteered in this study. Participants performed combined gripping with torqueing exertions for 5 min for two levels of frequency (10 and 20 exertions/min) at two levels of grip force (50 and 70 N), two levels of stroke rotation (30(○) and 60(○)) and three levels of grip-span (4.7, 6 and 7.3 cm). Therefore, a 2×2×2×3 full factorial design was used. The analysis of variance (ANOVA) showed that frequency, stroke rotation and grip-span were significant on discomfort score. Minimum discomfort and comfortable posture was found to be 90 N grip force with 10 exertions/min for 60° stroke rotation at 6-cm grip-span. The grip force, frequency and stroke rotation were found significant on EMG activity of forearm muscles using multivariate analysis of variance (MANOVA). The extensor muscles were found more activated than flexor muscles during the given task.

  11. Reconciling past changes in Earth's rotation with 20th century global sea-level rise: Resolving Munk's enigma.

    PubMed

    Mitrovica, Jerry X; Hay, Carling C; Morrow, Eric; Kopp, Robert E; Dumberry, Mathieu; Stanley, Sabine

    2015-12-01

    In 2002, Munk defined an important enigma of 20th century global mean sea-level (GMSL) rise that has yet to be resolved. First, he listed three canonical observations related to Earth's rotation [(i) the slowing of Earth's rotation rate over the last three millennia inferred from ancient eclipse observations, and changes in the (ii) amplitude and (iii) orientation of Earth's rotation vector over the last century estimated from geodetic and astronomic measurements] and argued that they could all be fit by a model of ongoing glacial isostatic adjustment (GIA) associated with the last ice age. Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~1.5 to 2.0 mm/year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA-corrected observations of Earth's rotation. We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations. This resolution adds confidence to recent estimates of individual contributions to 20th century sea-level change and to projections of GMSL rise to the end of the 21st century based on them.

  12. Gauge-origin independent calculation of magnetizabilities and rotational g tensors at the coupled-cluster level

    NASA Astrophysics Data System (ADS)

    Gauss, Jürgen; Ruud, Kenneth; Kállay, Mihály

    2007-08-01

    An implementation of the gauge-origin independent calculation of magnetizabilities and rotational g tensors at the coupled-cluster (CC) level is presented. The properties of interest are obtained as second derivatives of the energy with respect to the external magnetic field (in the case of the magnetizability) or with respect to magnetic field and rotational angular momentum (in the case of the rotational g tensor), while gauge-origin independence and fast basis-set convergence are ensured by using gauge-including atomic orbitals (London atomic orbitals) as well as their extension to treat rotational perturbations (rotational London atomic orbitals). The implementation within our existing CC analytic second-derivative code is described, focusing on the required modifications concerning integral evaluation and treatment of the unperturbed and perturbed two-particle density matrices. An extensive set of test calculations for LiH and BH (up to the full configuration-interaction limit), for a series of simple hydrides (HF, H2O, NH3, and CH4) as well as the more challenging molecules CO, N2, and O3 [employing the CC singles and doubles (CCSD) and the CCSD approximation augmented by a perturbative treatment of triple excitations] demonstrates the importance of electron correlation for high-accuracy predictions of magnetizabilities and rotational g tensors.

  13. Rotational properties of two-component Bose gases in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Meyer, Marius; Sreejith, Ganesh Jaya; Viefers, Susanne

    2015-03-01

    We study the rotational (yrast) spectra of dilute two-component atomic Bose gases in the low angular momentum regime, assuming equal interspecies and intraspecies interaction. Our analysis employs the composite fermion (CF) approach including a pseudospin degree of freedom. While the CF approach is not a priori expected to work well in this angular momentum regime, we show that composite fermion diagonalization gives remarkably accurate approximations to low energy states in the spectra. For angular momenta 0 < L < M (where N and M denote the numbers of particles of the two species, and M >= N), we find that the CF states span the full Hilbert space and provide a convenient set of basis states which, by construction, are eigenstates of the symmetries of the Hamiltonian. Within this CF basis, we identify a subset of the basis states with the lowest Λ-level kinetic energy. Diagonalization within this significally smaller subspace constitutes a major computational simplification and provides very close approximations to ground states and a number of low-lying states within each pseudospin and angular momentum channel. This work was financially supported by the Research Council of Norway and by NORDITA.

  14. Rotational properties of two-component Bose gases in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Meyer, M. L.; Sreejith, G. J.; Viefers, S.

    2014-04-01

    We study the rotational (yrast) spectra of dilute two-component atomic Bose gases in the low angular momentum regime, assuming equal interspecies and intraspecies interaction. Our analysis employs the composite fermion (CF) approach including a pseudospin degree of freedom. While the CF approach is not a priori expected to work well in this angular momentum regime, we show that composite fermion diagonalization gives remarkably accurate approximations to low-energy states in the spectra. For angular momenta 0level kinetic energy. Diagonalization within this significantly smaller subspace constitutes a major computational simplification and provides very close approximations to ground states and a number of low-lying states within each pseudospin and angular momentum channel.

  15. Earth Rotation and Geoid Constraints Upon The Modern Rate of Global Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Peltier, W. R.

    The explanation for the tide gauge inferred rate of secular sea level rise that has been ongoing over the last century remains enigmatic. Various explanations have been pro- posed for the fact that there is a large shortfall between the sum of the estimates of the steric and small ice sheets and glaciers contributions, respectively 0.6 mm yr-1 and ~0.3 mm yr-1 and the tide gauge inferred rate of ~1.8 mm yr-1( see Douglas and Peltier, Physics Today, March 2002 for a recent discussion). Possible explanations in- clude climate induced melting of the great polar ice sheets on Greenland and Antarc- tica, substantial upwards bias in the tide gauge inferred rates ( Cabanes et al., Science, 2002), or substantial underestimation of the steric rate most recently analysed in de- tail be Levitus and others(Science 2001,2002). Strong arguments exist as to why the second explanation is not likely to be correct. If we accept that the steric and small ice sheets estimates are reliable then we are forced to accept a significant contribution due to the modern day melting of polar ice. Yet the extent to which this contribution could be significant is strongly constrained by Earth rotation observations. I will ad- dress the issue as to how firm these constraints actually are. Grace observations of the time dependent geoid height, a signal which is also contaminated by the GIA process, as are Topex/Poseidon observations, once filtered to remove this effect, are expected to be immensely valuable in resolving the remaining uncertainties.

  16. Interaction of a two-level atom with single-mode optical field beyond the rotating wave approximation.

    PubMed

    Liu, Ju; Li, Zhi-Yuan

    2014-11-17

    One of the simplest models involving the atom-field interaction is the coupling of a single two-level atom with single-mode optical field. Under the rotating wave approximation, this problem is reduced to a form that can be solved exactly. But the approximation is only valid when the two levels are resonant or nearly resonant with the applied electromagnetic radiation. Here we present an analytical solution without the rotating wave approximation and applicable to general atom-field interaction far away from the resonance. We find that there exists remarkable influence of the initial phase of optical field on the Rabi oscillations and Rabi splitting, and this issue cannot be explored in the context of the rotating wave approximation. Due to the retention of the counter-rotating terms, higher-order harmonic appears during the Rabi splitting. The analytical solution suggests a way to regulate and control the quantum dynamics of a two-level atom and allows for exploring more essential features of the atom-field interaction.

  17. Rotational energy surface and quasiclassical analysis of the rotational energy level cluster formation in the ground vibrational state of PH 3

    NASA Astrophysics Data System (ADS)

    Petrov, Sergey V.; Kozlovskii, Borislav M.

    2007-06-01

    We report and substantiate a method for constructing the rotational energy surface (RES) of a molecule as a pure classical object. For an arbitrary molecule we start from the potential energy surface rather than from a conventional "effective Hamiltonian". The method is used for constructing the RES of the PH 3 molecule in its ground vibrational state. We have used an ab initio potential energy surface [D. Wang, Q. Shi, Q.-S. Zhu, J. Chem. Phys. 112 (2000) 9624-9631; S.N. Yurchenko, M. Carvajal, P. Jensen, F. Herregodts, T.R. Huet, Chem. Phys. 290 (2003) 59-67.]. The shape of the RES is shown not to change for J from 0 to 120. The procedure of quasiclassical quantization of the RES was also undertaken, yielding a set of quasiclassical critical values of the angular momentum. The results explain the structure of quantum rotational energy levels obtained by variational calculations [S.N. Yurchenko, W. Thiel, S. Patchkovskii, P. Jensen, Phys. Chem. Chem. Phys. 7 (2005) 573-582].

  18. Late Holocene shoreline behavior in embayments of Lake Michigan: Influence of quasi-periodic lake-level variations and sediment supply

    SciTech Connect

    Thompson, T.A.; Baedke, S.J. . Indiana Geological Survey)

    1994-04-01

    Lake Michigan contains numerous former embayments into glacial deposits or bedrock. Many of the embayments contain dunes, spits, and captured lakes, but others contain arcuate strandplains of beach ridges. The strandplains are a geologic record of shoreline behavior and lake-level variation throughout the late Holocene. The larger strandplains show similar long-term patterns of beach-ridge development. The similar patterns are expected because variations in lake level are a primary control on shoreline behavior, and all embayments would have experienced relatively the same lake-level changes. Some variations in the long-term pattern of shoreline development do occur between strandplains. These dissimilarities are primarily a function of different rates of sediment supply to the shoreline of each embayment. Beach-ridge development within embayments can be represented on a rate of water level change versus rate of sediment supply diagram (Curray diagram) as three superimposed ovals on the positive rate of sediment supply side of the diagram. The three stacked ovals represent the three quasi-periodic lake-level variations defined by Thompson (1992) and show the position of the shoreline for a given time within the Curray diagram fields. For shorelines with a high rate of sediment supply, only the 30-year quasi-periodic variation would reach the aggradation line. For shorelines having significantly less sediment supply, rising lake level on the 150- and 600-year variations would force the 30-year oval across the aggradation line and well into the depositional and possibly the erosional transgression fields. Under these conditions erosion would occur that may remove, stack, or at least prevent one or more beach ridges from being developed.

  19. In-fiber quasi-Michelson interferometer for liquid level measurement with a core-cladding-modes fiber end-face mirror

    NASA Astrophysics Data System (ADS)

    Rong, Qiangzhou; Qiao, Xueguang; Du, Yanying; Sun, Hao; Feng, Dingyi; Wang, Ruohui; Hu, Manli; Feng, Zhongyao

    2014-06-01

    An in-fiber quasi-Michelson interferometer (IFQMI) working on reflection is proposed and experimentally demonstrated for liquid level measurement. The device consists of a short piece of small-core fiber (SCF) followed by a standard single-mode fiber (SMF) where its end-face is terminated by a thick silver film. A well-defined interference pattern is obtained as the result of the fiber-core mismatch and core-cladding modes interference. The proposed device with a 30 mm pigtail SMF at a wavelength of 1555 nm presents a water level sensitivity of -68.3 pm/mm. Besides, the proposed device can also discriminate the refractive index (RI) of liquid measured. The IFQMI with 50 mm-long SMF provides a high RI sensitivity of -1200.61 (pm/mm)/RIU.

  20. Ab initio ground-state potential energy function and vibration-rotation energy levels of imidogen, NH.

    PubMed

    Koput, Jacek

    2015-06-30

    The accurate ground-state potential energy function of imidogen, NH, has been determined from ab initio calculations using the multireference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to octuple-zeta quality. The importance of several effects, including electron correlation beyond the MR-ACPF level of approximation, the scalar relativistic, adiabatic, and nonadiabatic corrections were discussed. Along with the large one-particle basis set, all of these effects were found to be crucial to attain "spectroscopic" accuracy of the theoretical predictions of vibration-rotation energy levels of NH.

  1. Lowest-Landau-level description of a Bose-Einstein condensate in a rapidly rotating anisotropic trap

    NASA Astrophysics Data System (ADS)

    Fetter, Alexander L.

    2007-01-01

    A rapidly rotating Bose-Einstein condensate in a symmetric two-dimensional trap can be described with the lowest Landau-level set of states. In this case, the condensate wave function ψ(x,y) is a Gaussian function of r2=x2+y2 , multiplied by an analytic function P(z) of the single complex variable z=x+iy ; the zeros of P(z) denote the positions of the vortices. Here, a similar description is used for a rapidly rotating anisotropic two-dimensional trap with arbitrary anisotropy (ωx/ωy⩽1) . The corresponding condensate wave function ψ(x,y) has the form of a complex anisotropic Gaussian with a phase proportional to xy , multiplied by an analytic function P(ζ) , where ζ∝x+iβ-y and 0⩽β-⩽1 is a real parameter that depends on the trap anisotropy and the rotation frequency. The zeros of P(ζ) again fix the locations of the vortices. Within the set of lowest Landau-level states at zero temperature, an anisotropic parabolic density profile provides an absolute minimum for the energy, with the vortex density decreasing slowly and anisotropically away from the trap center.

  2. Vortex lattices in a rotating Fermi superfluid in the BCS-BEC crossover with many Landau levels

    SciTech Connect

    Song, Tie-ling; Ma, C.R.; Ma, Yong-li

    2012-08-15

    We present an explicit analytical analysis of the ground state of vortex lattice structure, based on a minimization of the generalized Gross-Pitaevskii energy functional in a trapped rotating Fermi superfluid gas. By a Bogoliubov-like transformation we find that the coarse-grained average of the atomic density varies as inverted parabola in three dimensional cases; the Fermi superfluid in the BEC regime enters into the lowest Landau level at fast rotation, in which the vortices form an almost regular triangular lattice over a central region and the vortex lattice is expanded along the radial direction in the outer region; the fluid in the unitarity and BCS regimes occupies many low-lying Landau levels, in which a trapped gas with a triangular vortex lattice has a superfluid core surrounded by a normal gas. The calculation is qualitatively consistent with recent numerical and experimental data both in the vortex lattice structure and vortex numbers and in the density profiles versus the stirring frequency in the whole BCS-BEC crossover. - Highlights: Black-Right-Pointing-Pointer We present an analysis of vortex lattice in an interacting trapped rotating Fermi superfluid gas. Black-Right-Pointing-Pointer Decomposing the vortex from the condensate, we can explain the vortex lattice. Black-Right-Pointing-Pointer The calculation is consistent with numerical and experimental data. Black-Right-Pointing-Pointer It can characterize experimentally properties in different regimes of the BCS-BEC crossover.

  3. Observation of b2 symmetry vibrational levels of the SO2C 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

    DOE PAGES

    Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; ...

    2016-04-14

    Here, the C 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C state below 1600 cm–1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, itmore » allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.« less

  4. Observation of b2 symmetry vibrational levels of the SO2 C̃ (1)B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants.

    PubMed

    Park, G Barratt; Jiang, Jun; Saladrigas, Catherine A; Field, Robert W

    2016-04-14

    The C̃ (1)B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X̃ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C̃ state below 1600 cm(-1) of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry and to determine accurately the vibrational dependence of the rotational constants in the distorted C̃ electronic state.

  5. Quasi-Fermi level splitting evaluation based on electroluminescence analysis in multiple quantum-well solar cells for investigating cell performance under concentrated light

    NASA Astrophysics Data System (ADS)

    Inoue, Tomoyuki; Toprasertpong, Kasidit; Delamarre, Amaury; Watanabe, Kentaroh; Paire, Myriam; Lombez, Laurent; Guillemoles, Jean-François; Sugiyama, Masakazu; Nakano, Yoshiaki

    2016-03-01

    Insertion of InGaAs/GaAsP strain-balanced multiple quantum wells (MQWs) into i-regions of GaAs p-i-n solar cells show several advantages against GaAs bulk p-i-n solar cells. Particularly under high-concentration sunlight condition, enhancement of the open-circuit voltage with increasing concentration ratio in thin-barrier MQW cells has been reported to be more apparent than that in GaAs bulk cells. However, investigation of the MQW cell mechanisms in terms of I-V characteristics under high-concentration sunlight suffers from the increase in cell temperature and series resistance. In order to investigate the mechanism of the steep enhancement of open-circuit voltage in MQW cells under high-concentration sunlight without affected by temperature, the quasi-Fermi level splitting was evaluated by analyzing electroluminescence (EL) from a cell. Since a cell under current injection with a density Jinjhas similar excess carrier density to a cell under concentrated sunlight with an equivalent short-circuit current Jsc = Jinj, EL measurement with varied Jinj can approximately evaluate a cell performance under a variety of concentration ratio. In addition to the evaluation of quasi-Fermi level splitting, the external luminescence efficiency was also investigated with the EL measurement. The MQW cells showed higher external luminescence efficiency than the GaAs reference cells especially under high-concentration condition. The results suggest that since the MQW region can trap and confine carriers, the localized excess carriers inside the cells make radiative recombination more dominant.

  6. Pure rotational spectrometers for trace-level VOC detection and chemical sensing

    NASA Astrophysics Data System (ADS)

    Neill, Justin L.; Harris, Brent J.; Pulliam, Robin L.; Muckle, Matt T.; Reynolds, Roger; McDaniel, David; Pate, Brooks H.

    2014-05-01

    Pure rotational spectroscopy in the centimeter, millimeter, and THz regions of the electromagnetic spectrum is a powerful technique for the characterization of polar molecules in the gas phase. Although this technology has a long history in the research sector for structural characterization, recent advances in digital electronics have only recently made commercial instruments competitive with established chemical analysis techniques. BrightSpec is introducing a platform of pure rotational spectrometers in response to critical unmet needs in chemical analysis. These instruments aim to deliver the operational simplicity of Fourier transform infrared spectrometers in conjunction with the chemical analysis capabilities of mass spectrometers. In particular, the BrightSpec ONE instrument a broadband gas mixture analyzer with full capabilities for chemical analysis. This instrument implements Fourier transform millimeter-wave emission spectroscopy, wherein a brief excitation pulse is applied to the sample, followed by the measurement of the coherent free induction decay responses of all molecular transitions within the excitation bandwidth. After sample injection and characterization, the spectrometer returns a list of all known species detected in the sample, along with their concentrations in the mixture. No prior knowledge about the sample composition is required. The instrument can then perform double-resonance measurements (analogous to 2-D COSY NMR), direct mass determination through analysis of the time profile of the molecular signal, and automated isotopic identification as part of a suite of tools that can return the structural identity of the unknowns in the sample.

  7. Direct measurement of the temperature coefficient of the electron quasi-fermi level in dye-sensitized nanocrystalline solar cells using a titanium sensor electrode.

    PubMed

    Lobato, K; Peter, L M

    2006-11-02

    A novel type of dye-sensitized cell (DSC) with a passivated titanium sensor electrode located on top of the nanocrystalline titanium dioxide layer has been used to study the temperature dependence of the electron quasi-Fermi level relative to the I3-/I- redox-Fermi level under short circuit conditions. The results show that the Fermi level decreases with increasing temperature (-1.76 meV K(-1)) as predicted for diffusive electron transport at short circuit. A smaller temperature dependence (-0.25 meV K(-1)) of the position of the TiO2 conduction band relative to the I3-/I- redox-Fermi level was deduced from the shifts in the trap distribution. An expression for the temperature dependence of the open circuit voltage, U(photo), has been derived. The experimentally observed temperature dependence of U(photo) gave values of the activation energy (0.25 eV) and preexponential factor (10(8) s(-1)) for the transfer of electrons from the conduction band of the nanocrystalline TiO2 to triiodide ions.

  8. Calcium buffering properties of sarcoplasmic reticulum and calcium-induced Ca(2+) release during the quasi-steady level of release in twitch fibers from frog skeletal muscle.

    PubMed

    Fénelon, Karine; Lamboley, Cédric R H; Carrier, Nicole; Pape, Paul C

    2012-10-01

    Experiments were performed to characterize the properties of the intrinsic Ca(2+) buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([Ca(T)](SR) and [Ca(2+)](SR)) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca(2+) indicator). Results indicate SR Ca(2+) buffering was consistent with a single cooperative-binding component or a combination of a cooperative-binding component and a linear binding component accounting for 20% or less of the bound Ca(2+). Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca(2+)](SR) and [Ca(T)](SR) are 0.67 and 17.1 mM, respectively, and the dissociation constant, Hill coefficient, and concentration of the Ca-binding sites are 0.78 mM, 3.0, and 44 mM, respectively. This information can be used to calculate a variable proportional to the Ca(2+) permeability of the SR, namely d[Ca(T)](SR)/dt ÷ [Ca(2+)](SR) (denoted release permeability), in experiments in which only [Ca(T)](SR) or [Ca(2+)](SR) is measured. In response to a voltage-clamp step to -20 mV at 15°C, the release permeability reaches an early peak followed by a rapid decline to a quasi-steady level that lasts ~50 ms, followed by a slower decline during which the release permeability decreases by at least threefold. During the quasi-steady level of release, the release amplitude is 3.3-fold greater than expected from voltage activation alone, a result consistent with the recruitment by Ca-induced Ca(2+) release of 2.3 SR Ca(2+) release channels neighboring each channel activated by its associated voltage sensor. Release permeability at -60 mV increases as [Ca(T)](SR) decreases from its resting physiological level to ~0.1 of this level. This result argues against a release termination mechanism proposed in mammalian muscle fibers in which a luminal sensor of [Ca(2+)](SR) inhibits

  9. Effects of combined wrist flexion/extension and forearm rotation and two levels of relative force on discomfort.

    PubMed

    Khan, Abid Ali; O'Sullivan, Leonard; Gallwey, Timothy J

    2009-10-01

    This study investigated perceived discomfort in an isometric wrist flexion task. Independent variables were wrist flexion/extension (55%, 35% flexion, neutral, 35% and 55% extension ranges of motion (ROM)), forearm rotation (60%, 30% prone, neutral, 30% and 60% supine ROM) and two levels of flexion force (10% and 20% maximum voluntary contraction (MVC)). Discomfort was significantly affected by flexion force, forearm rotation and a two-way interaction of force with forearm rotation (each p < 0.05). High force for 60%ROM forearm pronation and supination resulted in increasingly higher discomfort for these combinations. Flexion forces were set relative to the MVC in each wrist posture and this appears to be important in explaining a lack of significant effect (p = 0.34) for flexion/extension on discomfort. Regression equations predicting discomfort were developed and used to generate iso-discomfort contours, which indicate regions where the risk of injury should be low and others where it is likely to be high. Regression equations predicting discomfort and iso-discomfort contours are presented, which indicate combinations of upper limb postures for which discomfort is predicted to be low, and others where it is likely to be high. These are helpful in the study of limits for risk factors associated with upper limb musculoskeletal injury in industry.

  10. Application of the generalized Euler series transformation for calculation of vibration-rotation energy levels of diatomic molecules

    NASA Astrophysics Data System (ADS)

    Kruglova, T. V.

    2004-01-01

    The detailed spectroscope information about highly excited molecules and radicals such us as H+3, H2, HI, H2O, CH2 is needed for a number of applications in the field of laser physics, astrophysics and chemistry. Studies of highly excited molecular vibration-rotation states face several problems connected with slowly convergence or even divergences of perturbation expansions. The physical reason for a perturbation expansion divergence is the large amplitude motion and strong vibration-rotation coupling. In this case one needs to use the special method of series summation. There were a number of papers devoted to this problem: papers 1-10 in the reference list are only example of studies on this topic. The present report is aimed at the application of GET method (Generalized Euler Transformation) to the diatomic molecule. Energy levels of a diatomic molecule is usually represented as Dunham series on rotational J(J+1) and vibrational (V+1/2) quantum numbers (within the perturbation approach). However, perturbation theory is not applicable for highly excited vibration-rotation states because the perturbation expansion in this case becomes divergent. As a consequence one need to use special method for the series summation. The Generalized Euler Transformation (GET) is known to be efficient method for summing of slowly convergent series, it was already used for solving of several quantum problems Refs.13 and 14. In this report the results of Euler transformation of diatomic molecule Dunham series are presented. It is shown that Dunham power series can be represented of functional series that is equivalent to its partial summation. It is also shown that transformed series has the butter convergent properties, than the initial series.

  11. Experimental determination of rotational constants of low-lying vibrational levels in the 0g- pure long-range state of ultracold Cs2 molecule

    NASA Astrophysics Data System (ADS)

    Wu, Jizhou; Liu, Wenliang; Li, Yuqing; Ma, Jie; Xiao, Liantuan; Jia, Suotang

    2017-04-01

    We report an accurate experimental determination of rotational constants of the lowest vibrational levels in the purely long-range state of ultracold cesium molecules (Cs2). We engineer a precise reference of the frequency difference through double photoassociation spectroscopy (PAS). The PAS for the lowest vibrational levels, v=0-3, has been obtained with an enhanced sensitivity and accuracy, according to which the binding energies have been corrected. As deduced from the reference, the frequency intervals between neighboring rotational levels are fitted to a non-rigid rotor model, thus the rotational constants are precisely obtained. The experimental results show good agreement with theoretical expectations.

  12. Is there a relationship between the performance in a chronometric mental-rotations test and salivary testosterone and estradiol levels in children aged 9-14 years?

    PubMed

    Quaiser-Pohl, Claudia; Jansen, Petra; Lehmann, Jennifer; Kudielka, Brigitte M

    2016-01-01

    The consistent gender differences favoring males in some spatial abilities like mental rotation have raised the question of whether testosterone or other gonadal hormones contribute to these differences--especially because such gender differences seem to appear mainly from the age of puberty on. Studies generally suggest that spatial ability is facilitated by moderately high testosterone levels (i.e., levels that are relatively high for females and relatively low for males). However, the role of sex steroids for mental-rotation performance of (pre-) pubertal children has not been the focus of research, yet. In our study, the relationships between different aspects of mental-rotation performance (accuracy, reaction time, rotation speed) and salivary testosterone and estradiol levels were investigated. Subjects were 109 children (51 boys and 58 girls) aged between 9 and 14 years (M = 11.41, SD = 1.74). They performed a chronometric mental-rotations test, in which the stimuli consisted of three-dimensional drawings of Shepard and Metzler cube figures. In addition, saliva samples were gathered for the analysis of free testosterone and estradiol levels. Results showed a significant gender difference in reaction time and rotational speed in favor of boys, and a significant age, but no gender difference in testosterone and estradiol levels. We found no significant relationships between hormonal levels and any measure of mental-rotation performance.

  13. Rotational Spectrum of SO_3 and Theoretical Evidence for the Formation of Rotational Energy Level Clusters in its Vibrational Ground State

    NASA Astrophysics Data System (ADS)

    Underwood, Daniel S.; Yurchenko, Sergei N.; Tennyson, Jonathan; Jensen, Per

    2014-06-01

    The structure of the purely rotational spectrum of sulphur trioxide SO_3 is investigated using a new synthetic line list. The list combines line positions from an empirical model with line intensities determined, in the form of Einstein coefficients, from variationally computed ro-vibrational wavefunctions in conjunction with an ab initio dipole moment surface. The empirical model providing the line positions involves an effective, Watsonian-type rotational Hamiltonian with literature parameter values resulting from least-squares fittings to observed transition frequencies. The formation of so-called rotational energy clusters at high rotational excitation are investigated. The SO_3 molecule is planar at equilibrium and exhibits a unique type of rotational-energy clustering associated with unusual stabilization axes perpendicular to the S--O bonds. This behaviour is characterized theoretically in the J range from 100 through 250. The wavefunctions for these cluster states are analysed, and the results are compared to those of a classical analysis in terms of the rotational-energy-surface formalism.

  14. Ab initio potential energy surface and vibration-rotation energy levels of silicon dicarbide, SiC2.

    PubMed

    Koput, Jacek

    2016-10-05

    The accurate ground-state potential energy surface of silicon dicarbide, SiC2 , has been determined from ab initio calculations using the coupled-cluster approach. Results obtained with the conventional and explicitly correlated coupled-cluster methods were compared. The core-electron correlation, higher-order valence-electron correlation, and scalar relativistic effects were taken into account. The potential energy barrier to the linear SiCC configuration was predicted to be 1782 cm(-1) . The vibration-rotation energy levels of the SiC2 , (29) SiC2 , (30) SiC2 , and SiC(13) C isotopologues were calculated using a variational method. The experimental vibration-rotation energy levels of the main isotopologue were reproduced to high accuracy. In particular, the experimental energy levels of the highly anharmonic vibrational ν3 mode of SiC2 were reproduced to within 6.7 cm(-1) , up to as high as the v3  = 16 state.

  15. Afterpulsing model based on the quasi-continuous distribution of deep levels in single-photon avalanche diodes

    NASA Astrophysics Data System (ADS)

    Horoshko, D. B.; Chizhevsky, V. N.; Kilin, S. Ya.

    2017-01-01

    We have performed a statistical characterization of the effect of afterpulsing in a free-running silicon single-photon detector by measuring the distribution of afterpulse waiting times in response to pulsed illumination and fitting it by a sum of exponentials. We show that a high degree of goodness of fit can be obtained for 5 exponentials, but the physical meaning of estimated characteristic times is dubious. We show that a continuous limit of the sum of exponentials with a uniform density between the limiting times gives excellent fitting results in the full range of the detector response function. This means that in certain detectors the afterpulsing is caused by a continuous band of deep levels in the active area of the photodetector.

  16. Calculated rotation-bending energy levels of CH 5+ and a comparison with experiment

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Carrington, Tucker

    2016-05-01

    We report J > 0 CH 5+ levels computed by fixing stretch coordinates. They are computed by using a simple product basis, exploiting symmetry, and carefully parallelizing the calculation. The J > 0 CH 5+ levels are compared with those obtained from other theoretical methods and with experimental ground state combination differences of Asvany et al. [Science, 347, 1346 (2015)]. If the assignment of Asvany et al. is correct, there are important differences between the levels we compute and those observed. We propose a different assignment of the experimental levels that reduces the maximum error from 34 to 2 cm-1. The new assignment can only be correct if states of both parities exist in the experiment. Although, ro-vibrational levels of CH 5+ cannot be associated with individual vibrational states, they do occur in blocks separated by gaps.

  17. High temperature heat source generation with quasi-continuous wave semiconductor lasers at power levels of 6 W for medical use.

    PubMed

    Fujimoto, Takahiro; Imai, Yusuke; Tei, Kazuyoku; Ito, Shinobu; Kanazawa, Hideko; Yamaguchi, Shigeru

    2014-01-01

    We investigate a technology to create a high temperature heat source on the tip surface of the glass fiber proposed for medical surgery applications. Using 4 to 6 W power level semiconductor lasers at a wavelength of 980 nm, a laser coupled fiber tip was preprocessed to contain a certain amount of titanium oxide powder with a depth of 100 μm from the tip surface so that the irradiated low laser energy could be perfectly absorbed to be transferred to thermal energy. Thus, the laser treatment can be performed without suffering from any optical characteristic of the material. A semiconductor laser was operated quasi-continuous wave mode pulse time duration of 180 ms and >95% of the laser energy was converted to thermal energy in the fiber tip. Based on two-color thermometry, by using a gated optical multichannel analyzer with a 0.25 m spectrometer in visible wavelength region, the temperature of the fiber tip was analyzed. The temperature of the heat source was measured to be in excess 3100 K.

  18. Effects of low-level laser therapy in combination with physiotherapy in the management of rotator cuff tendinitis.

    PubMed

    Eslamian, Fariba; Shakouri, Seyyed Kazem; Ghojazadeh, Morteza; Nobari, Ozra Eslampanah; Eftekharsadat, Bina

    2012-09-01

    Rotator cuff tendinitis is one of the main causes of shoulder pain. The objective of this study was to evaluate the possible additive effects of low-power laser treatment in combination with conventional physiotherapy endeavors in these patients. A total of 50 patients who were referred to the Physical Medicine and Rehabilitation Clinic with shoulder pain and rotator cuff disorders were selected. Pain severity measured with visual analogue scale (VAS), abduction, and external rotation range of motion in shoulder joint was measured by goniometry, and evaluation of daily functional abilities of patients was measured by shoulder disability questionnaire. Twenty-five of the above patients were randomly assigned into the control group and received only routine physiotherapy. The other 25 patients were assigned into the experimental group and received conventional therapy plus low-level laser therapy (4 J/cm(2) at each point over a maximum of ten painful points of shoulder region for total 5 min duration). The above measurements were assessed at the end of the third week of therapy in each group and the results were analyzed statistically. In both groups, statistically significant improvement was detected in all outcome measures compared to baseline (p < 0.05). Comparison between two different groups revealed better results for control of pain (reduction in VAS average) and shoulder disability problems in the experimental group versus the control (3.1 ± 2.2 vs. 5 ± 2.6, p = 0.029 and 4.4 ± 3.1 vs. 8.5 ± 5.1, p = 0.031, respectively ) after intervention. Positive objective signs also had better results in the experimental group, but the mean range of active abduction (144.92 ± 31.6 vs. 132.80 ± 31.3) and external rotation (78.0 ± 19.5 vs. 76.3 ± 19.1) had no significant difference between the two groups (p = 0.20 and 0.77, respectively). As one of physical modalities, gallium-arsenide low-power laser combined with

  19. Evaluation of the lubrication mechanism at various rotation speeds and granule filling levels in a container mixer using a thermal effusivity sensor.

    PubMed

    Uchiyama, Jumpei; Aoki, Shigeru

    2015-01-01

    To research the detailed mechanism of the lubrication process using the thermal effusivity sensor, the relationships of the lubrication progress with the pattern of powder flow, the rotation speed and the filling level were investigated. The thermal effusivity profile was studied as a function of the number of rotations at various rotation speeds. It was observed that at lower rotation speeds, the profiles of the lubrication progress were almost the same, regardless of the rotation speed. In this region, the highest speed was defined as the critical rotation speed (CRS), which was found to be one of the important factors. The CRS had close relations with avalanche flow in the blender. The first and the second phases were observed in the lubrication process. The first phase was influenced by the CRS and the filling level in the blender. The second phase was influenced by the rotation speed. The mechanism of two-phase process was proposed as a macro progression of the dispersion of the lubricant (first phase) and micro progression of the coating of the powder particles with lubricant (second phase). The accurate monitoring by the thermal effusivity sensor was able to help a better understanding in the lubrication process.

  20. Non-Born-Oppenheimer calculations of the rovibrational spectrum of H2 excited to the second rotational level

    NASA Astrophysics Data System (ADS)

    Jones, Keith; Formanek, Martin; Adamowicz, Ludwik

    2017-02-01

    Quantum mechanical, non-relativistic, non-Born-Oppenheimer (non-BO) calculations are performed for the rovibrational spectrum of H2 excited to the second rotational level. The non-BO wave functions of the considered states are expanded in terms of all-particle explicitly correlated Gaussian functions. The dissociation energies and rovibrational transition energies are calculated and compared with experimental values and values obtained in calculations performed by others. The average interparticle distances are calculated and compared with the corresponding values for HD. They show that H2 is a more "diffuse molecule". The nuclear-nuclear correlation functions are calculated and plotted to visualize the "non-BO molecular structure" of H2.

  1. Effects of stocking rates on gastrointestinal nematode infection levels in a goat/cattle rotational stocking system.

    PubMed

    Mahieu, Maurice

    2013-11-15

    Gastrointestinal nematodes (GIN) are increasingly resistant to anthelmintic drugs worldwide, so integrated control methods are more and more needed for the sustainability of small ruminant farming. Such methods rely on knowledge in epidemiology, physiology, and genetics. Ecological studies have highlighted the effect of host density on parasite populations, and in the humid tropics, rotational grazing systems were designed according to the survival of GIN free-living stages. This study aimed to assess the effects of mixed stocking and host stocking rate on host GIN infection level. Four groups of 15-17 Creole male kids were raised on irrigated pasture from weaning (about 3 months) until the age of 7 months, at four partial stocking rates (pSR): 100% (control), 75% (G75), 50% (G50), and 25% (G25) of the total stocking rate of the pasture. The last three groups were associated with weaned Creole heifers to obtain the same overall stocking rate as the control. Animals grazed in a 'leader' goat and 'follower' cattle design: the G25, G50, and G75 paddocks were split into six plots; each plot was grazed by goats for 1 week and by heifers the following week. The pasture then rested for 4 weeks before the animals were returned for a new grazing sequence. Five control plots were grazed rotationally for 1 week, and rested for 4 weeks. This design was repeated three times a year for a total of 10 repetitions. Average faecal egg counts (FEC) decreased according to a power function of the pSR: FEC=1829pSR(3.7). The observed death rate decreased significantly with the pSR (27.6%, 16.4%, 11.9%, and 12.2%). The kids grew faster in G25 (51 g d(-1)) than in G50 (43 g d(-1)) and G75 or control (32 g d(-1), p<0.05). Heifers were not significantly infected with GIN and grew normally (about 0.48 kg d(-1)). Reducing the pSR by associating a non-host species in a rotational stocking system may be a very promising component of integrated GIN control, at least for the humid tropics.

  2. Quasi-Fibonacci oscillators

    NASA Astrophysics Data System (ADS)

    Gavrilik, A. M.; Kachurik, I. I.; Rebesh, A. P.

    2010-06-01

    We study the properties of the sequences of the energy eigenvalues for some generalizations of q-deformed oscillators including the p, q-oscillator, and the three-, four- and five-parameter deformed oscillators given in the literature. It is shown that most of the considered models belong to the class of so-called Fibonacci oscillators for which any three consecutive energy levels satisfy the relation En + 1 = λEn + ρEn - 1 with real constants λ, ρ. On the other hand, for a certain μ-oscillator known since 1993, we prove its non-Fibonacci nature. Possible generalizations of the three-term Fibonacci relation are discussed, among which for the μ-oscillator we choose, as the most adequate, the so-called quasi-Fibonacci (or local Fibonacci) property of the energy levels. The property is encoded in the three-term quasi-Fibonacci (QF) relation with the non-constant, n-dependent coefficients λ and ρ. Various aspects of the QF relation are elaborated for the μ-oscillator and some of its extensions.

  3. Analysis of the Rotation-Torsion Spectrum of CH_2DOH Within the e_0, e_1, and o_1 Torsional Levels

    NASA Astrophysics Data System (ADS)

    Coudert, L. H.; Pearson, John C.; Yu, Shanshan; Margules, L.; Motiyenko, R. A.; Klee, S.

    2013-06-01

    Since the first assignments of Quade and coworkers, a more satisfactory understanding of the spectrum of CH_2DOH has now been achieved. Thanks to a multidimensional potential energy surface and to a new theoretical approach accounting for the internal rotation of a partially deuterated methyl group, 76 torsional subbands could be identified in the microwave and FIR domains. 8356 rotation and rotation-torsion transitions were also assigned for the three lowest lying torsional levels, e_0, e_1, and o_1, in the microwave and terahertz domains and were analyzed with empirical models. In this paper, a new approach aimed at accounting for the rotation-torsion energy levels of CH_2DOH will be presented. It is based on the exact expression of the generalized 4× 4 inertia tensor of the molecule and accounts for the C_s symmetry of the partially deuterated methyl group, for the dependence of the rotational constants on the angle of internal rotation, and for the rotation-torsion Coriolis coupling. This approach will be used to analyze high-resolution data involving the three lowest lying torsional levels, up to k=11. In addition to the microwave data reported recently,^d new transitions recorded in the terahertz domain at JPL will be analyzed. The results of the analysis will be presented in the paper and the parameters determined in the analysis will be discussed. Quade and Suenram, J. Chem. Phys. {73} (1980) 1127; and Su and Quade, J. Mol. Spec. {134} (1989) 290. Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spec. {256} (2009) 204. El Hilali, Coudert, Konov, and Klee, J. Chem. Phys. {135} (2011) 194309. Pearson, Yu, and Drouin, J. Mol. Spec. {280} (2012) 119. Quade and Lin, J. Chem. Phys. {38} (1963) 540.

  4. Reconciling past changes in Earth’s rotation with 20th century global sea-level rise: Resolving Munk’s enigma

    PubMed Central

    Mitrovica, Jerry X.; Hay, Carling C.; Morrow, Eric; Kopp, Robert E.; Dumberry, Mathieu; Stanley, Sabine

    2015-01-01

    In 2002, Munk defined an important enigma of 20th century global mean sea-level (GMSL) rise that has yet to be resolved. First, he listed three canonical observations related to Earth’s rotation [(i) the slowing of Earth’s rotation rate over the last three millennia inferred from ancient eclipse observations, and changes in the (ii) amplitude and (iii) orientation of Earth’s rotation vector over the last century estimated from geodetic and astronomic measurements] and argued that they could all be fit by a model of ongoing glacial isostatic adjustment (GIA) associated with the last ice age. Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~1.5 to 2.0 mm/year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA-corrected observations of Earth’s rotation. We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations. This resolution adds confidence to recent estimates of individual contributions to 20th century sea-level change and to projections of GMSL rise to the end of the 21st century based on them. PMID:26824058

  5. The analemma criterion: accidental quasi-satellites are indeed true quasi-satellites

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-11-01

    In the Solar system, a quasi-satellite is an object that follows a heliocentric path with an orbital period that matches almost exactly with that of a host body (planetary or not). The trajectory is of such nature that, without being gravitationally attached, the value of the angular separation between host and quasi-satellite as seen from the Sun remains confined within relatively narrow limits for time-spans that exceed the length of the host's sidereal orbital period. Here, we show that under these conditions, a quasi-satellite traces an analemma in the sky as observed from the host in a manner similar to that found for geosynchronous orbits. The analemmatic curve (figure-eight-, teardrop-, ellipse-shaped) results from the interplay between the tilt of the rotational axis of the host and the properties of the orbit of the quasi-satellite. The analemma criterion can be applied to identify true quasi-satellite dynamical behaviour using observational or synthetic astrometry and it is tested for several well-documented quasi-satellites. For the particular case of 15810 (1994 JR1), a putative accidental quasi-satellite of dwarf planet Pluto, we show explicitly that this object describes a complex analemmatic curve for several Plutonian sidereal periods, confirming its transient quasi-satellite status.

  6. Chiral Bands for Quasi-Proton and Quasi-Neutron Coupling with a Triaxial Rotor

    NASA Astrophysics Data System (ADS)

    Qi, B.; Zhang, S. Q.; Wang, S. Y.; Meng, J.

    2008-04-01

    A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of an h11/2 proton and an h11/2 quasi-neutron. With pairing treated by the BCS approximation, the present quasi-particle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. It is found that aplanar rotation or equivalently chiral geometry exists beyond the usual one proton and one neutron hole coupled with a triaxial rotor. After including the pairing correlation, the model describes the candidate chiral bands in 126Cs successfully, which supports the interpretation of chirality geometry.

  7. A proposal for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity QED.

    PubMed

    Yang, Chui-Ping

    2011-06-08

    We present a method for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity quantum electrodynamics. The two logical states of a qubit are represented by the two lowest levels of each system while a higher energy level is used for the gate implementation. The method operates essentially by preparing a W state conditioned on the states of the control qubits, creating a single photon in the cavity mode, and then performing an arbitrary rotation on the states of the target qubit with the assistance of the cavity photon. It is interesting to note that the basic operational steps for implementing the proposed gate do not increase with the number of qubits n, and the gate operation time decreases as the number of qubits increases. This proposal is quite general, and can be applied to various types of superconducting devices in a cavity or coupled to a resonator.

  8. Excited vibrational level rotational constants for SiC2: A sensitive molecular diagnostic for astrophysical conditions

    NASA Astrophysics Data System (ADS)

    Fortenberry, Ryan C.; Lee, Timothy J.; Müller, Holger S. P.

    2015-11-01

    Silacyclopropynylidene, SiC2, is a known and highly abundant circumstellar molecule. Its spectrum has been established as a major component of lines observed toward the carbon-rich star IRC +10216 (CW Leonis). It has been detected in its low-lying v3 = 1 and 2 vibrational states as well as in various isotopic compositions. Increasing sensitivity and spatial resolution will enable many more emission or absorption lines to be detected. In order to detect new molecular species, unassigned lines of known species must be identified. This work uses established ab initio quartic force fields to produce data necessary for this classification of lines related to SiC2. Agreement between the theoretical vibrational frequencies and known rotational and spectroscopic constants is quite good, as good as 5 cm-1 and 3 MHz, respectively in some cases. In addition, experimentally unknown vibrational frequencies and rotational constants are provided for the first overtones and combination bands in addition to 3ν3, the second overtone of the low-lying antisymmetric stretch/carbide rotation mode. Frequencies of v3 = 3 low-J rotational transitions of the main isotopic species are also estimated from published data for v3 ≤ 2. Further, we determine rotational and centrifugal distortion parameters for which in most cases vibrational effects due to the ν3 mode were reduced to first, and in several cases also to second order. These values may approximate equilibrium values better than the ground state values. The data produced herein will aid in the experimental and observational characterization of this known astromolecule in order to identify some of the unassigned lines for a known entity.

  9. New approach to evaluate the lubrication process in various granule filling levels and rotating mixer sizes using a thermal effusivity sensor.

    PubMed

    Uchiyama, Jumpei; Aoki, Shigeru; Uemoto, Yoshifumi

    2015-01-01

    The principles of thermal effusivity are applied to an understanding of the detailed mechanisms of the lubrication process in a rotating mixer. The relationships and impact of the lubrication process by the pattern of powder flow, the filling level, and the rotating mixer size were investigated. Thermal effusivity profiles of the lubrication process, as obtained, indicate that lubrication is a two-phase process. The intersection point of the first and second phases (IPFS) is influenced by changing the filling level, thus changing the resulting number of avalanche flows created. The slope of the second phase (SSP) is influenced by the relationship between the number and the length of avalanche flows. Understanding this difference between the first and second phases is important to successfully evaluate the impact of proposed changes in the lubrication process. From this knowledge, a predictive model of the lubrication profile can be generated to allow an evaluation of proposed changes to the lubrication process. This model allows estimation of the lubrication profile at different filling levels and in different rotating mixer sizes. In this study, the actual lubrication profile almost coincides with the model predicted lubrication profile. Based on these findings, it is assumed that lubrication profiles at a commercial scale can be predicted from data generated at the laboratory scale. Further, it is assumed that changes in the filling level can also be estimated from the laboratory or current data.

  10. Effects of Age, Gender and Level of Co-contraction on Elbow and Shoulder Rotational Stiffness and Damping in the Impulsively End-Loaded Upper Extremity.

    PubMed

    Lee, Yunju; Ashton-Miller, James A

    2015-05-01

    Whether an arm will buckle under an impulsive end-load should partly depend on the elastic and viscous properties of the pretensed arm muscles. In measuring these properties we hypothesized that neither age, gender, nor muscle pre-contraction level would affect the bilinear elbow or shoulder lumped rotational stiffness or damping parameters in the impulsively end-loaded upper extremity of 38 healthy men and women. Subjects were instructed to preactivate triceps to either 25, 50 or 75% of maximum myoelectric activity levels. Then a standardized impulsive end-load was applied via a 6-axis load cell to the wrist of the slightly flexed arm in the prone posture. Arm kinematic responses were acquired at 280 Hz and an inverse dynamics analysis was used to estimate the bilinear rotational stiffnesses and damping parameters at the elbow and shoulder. The results show that pre-contraction level affected normalized joint rotational stiffness and damping coefficients (p < 0.02). Age affected the initial stiffness for the elbow (p < 0.05), and gender affected that of the shoulder in the sagittal plane (p < 0.006). Arm muscle strength was positively related to normalized stiffness at the elbow, but not the shoulder. We conclude that age, gender and pre-contraction level each affect the viscoelastic behavior of the end-loaded upper extremity in healthy adults.

  11. You Should Be the Specialist! Weak Mental Rotation Performance in Aviation Security Screeners - Reduced Performance Level in Aviation Security with No Gender Effect.

    PubMed

    Krüger, Jenny K; Suchan, Boris

    2016-01-01

    Aviation security screeners analyze a large number of X-ray images per day and seem to be experts in mentally rotating diverse kinds of visual objects. A robust gender-effect that men outperform women in the Vandenberg & Kuse mental rotation task has been well documented over the last years. In addition it has been shown that training can positively influence the overall task-performance. Considering this, the aim of the present study was to investigate whether security screeners show better performance in the Mental Rotation Test (MRT) independently of gender. Forty-seven security screeners of both sexes from two German airports were examined with a computer based MRT. Their performance was compared to a large sample of control subjects. The well-known gender-effect favoring men on mental rotation was significant within the control group. However, the security screeners did not show any sex differences suggesting an effect of training and professional performance. Surprisingly this specialized group showed a lower level of overall MRT performance than the control participants. Possible aviation related influences such as secondary effects of work-shift or expertise which can cumulatively cause this result are discussed.

  12. You Should Be the Specialist! Weak Mental Rotation Performance in Aviation Security Screeners – Reduced Performance Level in Aviation Security with No Gender Effect

    PubMed Central

    Krüger, Jenny K.; Suchan, Boris

    2016-01-01

    Aviation security screeners analyze a large number of X-ray images per day and seem to be experts in mentally rotating diverse kinds of visual objects. A robust gender-effect that men outperform women in the Vandenberg & Kuse mental rotation task has been well documented over the last years. In addition it has been shown that training can positively influence the overall task-performance. Considering this, the aim of the present study was to investigate whether security screeners show better performance in the Mental Rotation Test (MRT) independently of gender. Forty-seven security screeners of both sexes from two German airports were examined with a computer based MRT. Their performance was compared to a large sample of control subjects. The well-known gender-effect favoring men on mental rotation was significant within the control group. However, the security screeners did not show any sex differences suggesting an effect of training and professional performance. Surprisingly this specialized group showed a lower level of overall MRT performance than the control participants. Possible aviation related influences such as secondary effects of work-shift or expertise which can cumulatively cause this result are discussed. PMID:27014142

  13. Toward a Principled Sampling Theory for Quasi-Orders

    PubMed Central

    Ünlü, Ali; Schrepp, Martin

    2016-01-01

    Quasi-orders, that is, reflexive and transitive binary relations, have numerous applications. In educational theories, the dependencies of mastery among the problems of a test can be modeled by quasi-orders. Methods such as item tree or Boolean analysis that mine for quasi-orders in empirical data are sensitive to the underlying quasi-order structure. These data mining techniques have to be compared based on extensive simulation studies, with unbiased samples of randomly generated quasi-orders at their basis. In this paper, we develop techniques that can provide the required quasi-order samples. We introduce a discrete doubly inductive procedure for incrementally constructing the set of all quasi-orders on a finite item set. A randomization of this deterministic procedure allows us to generate representative samples of random quasi-orders. With an outer level inductive algorithm, we consider the uniform random extensions of the trace quasi-orders to higher dimension. This is combined with an inner level inductive algorithm to correct the extensions that violate the transitivity property. The inner level correction step entails sampling biases. We propose three algorithms for bias correction and investigate them in simulation. It is evident that, on even up to 50 items, the new algorithms create close to representative quasi-order samples within acceptable computing time. Hence, the principled approach is a significant improvement to existing methods that are used to draw quasi-orders uniformly at random but cannot cope with reasonably large item sets. PMID:27965601

  14. Toward a Principled Sampling Theory for Quasi-Orders.

    PubMed

    Ünlü, Ali; Schrepp, Martin

    2016-01-01

    Quasi-orders, that is, reflexive and transitive binary relations, have numerous applications. In educational theories, the dependencies of mastery among the problems of a test can be modeled by quasi-orders. Methods such as item tree or Boolean analysis that mine for quasi-orders in empirical data are sensitive to the underlying quasi-order structure. These data mining techniques have to be compared based on extensive simulation studies, with unbiased samples of randomly generated quasi-orders at their basis. In this paper, we develop techniques that can provide the required quasi-order samples. We introduce a discrete doubly inductive procedure for incrementally constructing the set of all quasi-orders on a finite item set. A randomization of this deterministic procedure allows us to generate representative samples of random quasi-orders. With an outer level inductive algorithm, we consider the uniform random extensions of the trace quasi-orders to higher dimension. This is combined with an inner level inductive algorithm to correct the extensions that violate the transitivity property. The inner level correction step entails sampling biases. We propose three algorithms for bias correction and investigate them in simulation. It is evident that, on even up to 50 items, the new algorithms create close to representative quasi-order samples within acceptable computing time. Hence, the principled approach is a significant improvement to existing methods that are used to draw quasi-orders uniformly at random but cannot cope with reasonably large item sets.

  15. Generalized quasi variational inequalities

    SciTech Connect

    Noor, M.A.

    1996-12-31

    In this paper, we establish the equivalence between the generalized quasi variational inequalities and the generalized implicit Wiener-Hopf equations using essentially the projection technique. This equivalence is used to suggest and analyze a number of new iterative algorithms for solving generalized quasi variational inequalities and the related complementarity problems. The convergence criteria is also considered. The results proved in this paper represent a significant improvement and refinement of the previously known results.

  16. Chiral bands for a quasi-proton and quasi-neutron coupled with a triaxial rotor

    NASA Astrophysics Data System (ADS)

    Zhang, S. Q.; Qi, B.; Wang, S. Y.; Meng, J.

    2007-04-01

    A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of an h11/2 proton and an h11/2 quasi-neutron. With pairing treated by the BCS approximation, the present quasiparticle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. After a detailed analysis of the angular momentum orientations, energy separation between the partner bands, and behavior of electromagnetic transitions, for the first time we find aplanar rotation or equivalently chiral geometry beyond the usual one proton and one neutron hole coupled with a triaxial rotor.

  17. Rotating Vesta

    NASA Video Gallery

    Astronomers combined 146 exposures taken by NASA's Hubble SpaceTelescope to make this 73-frame movie of the asteroid Vesta's rotation.Vesta completes a rotation every 5.34 hours.› Asteroid and...

  18. IUPAC critical evaluation of the rotational-vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H216O

    NASA Astrophysics Data System (ADS)

    Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Al Derzi, Afaf R.; Fábri, Csaba; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Lodi, Lorenzo; Mizus, Irina I.

    2013-03-01

    This is the third of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational-vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O containstwo components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system

  19. Photonic quasi-crystal terahertz lasers.

    PubMed

    Vitiello, Miriam Serena; Nobile, Michele; Ronzani, Alberto; Tredicucci, Alessandro; Castellano, Fabrizio; Talora, Valerio; Li, Lianhe; Linfield, Edmund H; Davies, A Giles

    2014-12-19

    Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of 'defects', which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1-0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum.

  20. Photonic quasi-crystal terahertz lasers

    PubMed Central

    Vitiello, Miriam Serena; Nobile, Michele; Ronzani, Alberto; Tredicucci, Alessandro; Castellano, Fabrizio; Talora, Valerio; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles

    2014-01-01

    Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of ‘defects’, which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1–0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum. PMID:25523102

  1. Effect of diversified crop rotations on groundwater levels and crop water productivity in the North China Plain

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolin; Chen, Yuanquan; Pacenka, Steven; Gao, Wangsheng; Ma, Li; Wang, Guangya; Yan, Peng; Sui, Peng; Steenhuis, Tammo S.

    2015-03-01

    Water shortage is the major bottleneck that limits sustainable yield of agriculture in the North China Plain. Due to the over-exploitation of groundwater for irrigating the winter wheat-summer maize double cropping systems, a groundwater crisis is becoming increasingly serious. To help identify more efficient and sustainable utilization of the limited water resources, the water consumption and water use efficiency of five irrigated cropping systems were calculated and the effect of cropping systems on groundwater table changes was estimated based on a long term field experiment from 2003 to 2013 in the North China Plain interpreted using a soil-water-balance model. The five cropping systems included sweet potato → cotton → sweet potato → winter wheat-summer maize (SpCSpWS, 4-year cycle), ryegrass-cotton → peanuts → winter wheat-summer maize (RCPWS, 3-year cycle), peanuts → winter wheat-summer maize (PWS, 2-year cycle), winter wheat-summer maize (WS, 1-year cycle), and continuous cotton (Cont C). The five cropping systems had a wide range of annual average actual evapotranspiration (ETa): Cont C (533 mm/year) < SpCSpWS (556 mm/year) < PWS (615 mm/year) < RCPWS (650 mm/year) < WS rotation (734 mm/year). The sequence of the simulated annual average groundwater decline due to the five cropping systems was WS (1.1 m/year) > RCPWS (0.7 m/year) > PWS (0.6 m/year) > SPCSPWS and Cont C (0.4 m/year). The annual average economic output water use efficiency (WUEe) increased in the order SpCSpWS (11.6 yuan ¥ m-3) > RCPWS (9.0 ¥ m-3) > PWS (7.3 ¥ m-3) > WS (6.8 ¥ m-3) > Cont C (5.6 ¥ m-3) from 2003 to 2013. Results strongly suggest that diversifying crop rotations could play a critically important role in mitigating the over-exploitation of the groundwater, while ensuring the food security or boosting the income of farmers in the North China Plain.

  2. Rotating Bioreactor

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues currently being cultured in rotating bioreactors by investigators.

  3. Quasi-Static Electric Field Generator

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R. (Inventor)

    2017-01-01

    A generator for producing an electric field for with an inspection technology system is provided. The generator provides the required variable magnitude quasi-static electric fields for the "illumination" of objects, areas and volumes to be inspected by the system, and produces human-safe electric fields that are only visible to the system. The generator includes a casing, a driven, non-conducting and triboelectrically neutral rotation shaft mounted therein, an ungrounded electrostatic dipole element which works in the quasi-static range, and a non-conducting support for mounting the dipole element to the shaft. The dipole element has a wireless motor system and a charging system which are wholly contained within the dipole element and the support that uses an electrostatic approach to charge the dipole element.

  4. Rotational testing.

    PubMed

    Furman, J M

    2016-01-01

    The natural stimulus for the semicircular canals is rotation of the head, which also might stimulate the otolith organs. Vestibular stimulation usually induces eye movements via the vestibulo-ocular reflex (VOR). The orientation of the subject with respect to the axis of rotation and the orientation of the axis of rotation with respect to gravity together determine which labyrinthine receptors are stimulated for particular motion trajectories. Rotational testing usually includes the measurement of eye movements via a video system but might use a subject's perception of motion. The most common types of rotational testing are whole-body computer-controlled sinusoidal or trapezoidal stimuli during earth-vertical axis rotation (EVAR), which stimulates primarily the horizontal semicircular canals bilaterally. Recently, manual impulsive rotations, known as head impulse testing (HIT), have been developed to assess individual horizontal semicircular canals. Most types of rotational stimuli are not used routinely in the clinical setting but may be used in selected research environments. This chapter will discuss clinically relevant rotational stimuli and several types of rotational testing that are used primarily in research settings.

  5. THE QUASI NONGOVERNMENTAL ORGANIZATION.

    ERIC Educational Resources Information Center

    PIFER, ALAN

    ORGANIZED TO MEET URGENT NATIONAL NEEDS, PROVIDE INDEPENDENT JUDGMENT, AND OFFER FRESH SOLUTIONS TO COMPLEX PROBLEMS, THE QUASI NONGOVERNMENTAL ORGANIZATION IS DEFINED AS A NONPROFIT ASSOCIATION OR INSTITUTION LODGED IN THE PRIVATE SECTOR OF SOCIETY BUT FINANCED LARGELY OR ENTIRELY BY THE FEDERAL GOVERNMENT, RESPONSIBLE TO ITS OWN BOARD OF…

  6. Riemann quasi-invariants

    SciTech Connect

    Pokhozhaev, Stanislav I

    2011-06-30

    The notion of Riemann quasi-invariants is introduced and their applications to several conservation laws are considered. The case of nonisentropic flow of an ideal polytropic gas is analysed in detail. Sufficient conditions for gradient catastrophes are obtained. Bibliography: 16 titles.

  7. Quasi-Anonymous Channels

    DTIC Science & Technology

    2003-01-01

    QUASI- ANONYMOUS CHANNELS Ira S. Moskowitz Center for High Assurance Computer Systems - Code 5540 Naval Research Laboratory, Washington, DC...Assurance Computer Systems - Code 5540 Naval Research Laboratory, Washington, DC 20375, USA Abstract Although both anonymity and covert...channels are part of the larger topic of information hiding, there also exists an intrinsic linkage between anonymity and covert channels. This linkage

  8. Quasi-Normal Modes of Stars and Black Holes.

    PubMed

    Kokkotas, Kostas D; Schmidt, Bernd G

    1999-01-01

    Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of view. The discussion includes perturbations of black holes (Schwarzschild, Reissner-Nordström, Kerr and Kerr-Newman) and relativistic stars (non-rotating and slowly-rotating). The properties of the various families of quasi-normal modes are described, and numerical techniques for calculating quasi-normal modes reviewed. The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.

  9. Method for Design Rotation

    DTIC Science & Technology

    1993-08-01

    desirability of a rotation as a function of the set of planar angles. Criteria for the symmetry of the design (such as the same set of factor levels for...P is -1. Hence there is no theoretical problem in obtaining rotations of a design; there are only the practical questions Why rotate a design? And...star points, which can be represented in a shorthand notation by the permutations of (±1,0, "’" , 0), and (c) factorial points, which are a two- level

  10. Vibrational and rotational energy transfers involving the CH B 2Σ- v=1 vibrational level in collisions with Ar, CO, and N2O

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Yi; Tsai, Ming-Tsang; Lin, King-Chuen

    2006-04-01

    With photolysis-probe technique, we have studied vibrational and rotational energy transfers of CH involving the B Σ-2 (v =1, 0⩽N⩽6, F) state by collisions with Ar, CO, and N2O. For the vibrational energy transfer (VET) measurements, the time-resolved fluorescence of the B-X(0,0) band is monitored following the (1,0) band excitation. For the rotational energy transfer (RET) measurements, the laser-induced fluorescence of the initially populated state is dispersed using a step-scan Fourier transform spectrometer. The time-resolved spectra obtained in the nanosecond regime may yield the RET information under a single pressure of the collider. The rate constants of intramolecular energy transfers are evaluated with simulation of kinetic models. The VET lies in the range of 4×10-12to4×10-11cm3molecule-1s-1, with efficiency following the order of Ar rotational distribution. The RET rates are more rapid by one to two orders of magnitude, comparable to the gas kinetic, with the trend of Ar level reported previously. In general, the propensity rules obeyed in the v =0 collision with Ar are valid in v =1, but the latter case shows a weaker tendency. It might be caused by the anisotropy difference of interaction potential when vibrational excitation is considered. For the polyatomic collider, the strong long-range dipole-dipole interaction

  11. Interaction of a Λ-type three-level atom with a single-mode field without rotating wave approximation: perturbation theory approach

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, M.; Tavassoly, M. K.

    2015-02-01

    In this article, by using the perturbation theory, we analytically solve the eigenvalue problem for the Hamiltonian describing the interaction of a Λ-type three-level atom with a single-mode radiation field without the rotating wave approximation (RWA). For this purpose, the atom-field interaction Hamiltonian, which contains the counter-rotating terms (CRTs), is transformed to an analytically solvable Hamiltonian by applying three successive unitary transformations. According to our calculations, the contribution of CRTs within the transformed Hamiltonian is in fact replaced by transforming the ‘constant detuning’ with the ‘intensity-dependent detuning’ in the first order, and the ‘constant atom-field coupling’ with the intensity-dependent coupling in the second order of the perturbation parameters. Then, by solving the eigenvalue problem for the transformed Hamiltonian, the eigenvector of the considered atom-field Hamiltonian is obtained analytically. Finally, after achieving the state vector of the atom-field system at an arbitrary time, a few nonclassical properties of the system state are investigated numerically. Meanwhile, we compare our results with the presence of RWA, from which the role of CRTs will be established.

  12. Rotating Wavepackets

    ERIC Educational Resources Information Center

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  13. Research on Earth's rotation and the effect of atmospheric pressure on vertical deformation and sea level variability

    NASA Technical Reports Server (NTRS)

    Wahr, John

    1993-01-01

    The work done under NASA grant NAG5-485 included modelling the deformation of the earth caused by variations in atmospheric pressure. The amount of deformation near coasts is sensitive to the nature of the oceanic response to the pressure. The PSMSL (Permanent Service for Mean Sea Level) data suggest the response is inverted barometer at periods greater than a couple months. Green's functions were constructed to describe the perturbation of the geoid caused by atmospheric and oceanic loading and by the accompanying load-induced deformation. It was found that perturbation of up to 2 cm are possible. Ice mass balance data was used for continental glaciers to look at the glacial contributions to time-dependent changes in polar motion, the lod, the earth's gravitational field, the position of the earth's center-of-mass, and global sea level. It was found that there can be lateral, non-hydrostatic structure inside the fluid core caused by gravitational forcing from the mantle, from the inner core, or from topography at the core/mantle or inner core/outer core boundaries. The nutational and tidal response of a non-hydrostatic earth with a solid inner core was modeled. Monthly, global tide gauge data from PSMSL was used to look at the 18.6-year ocean tide, the 14-month pole tide, the oceanic response to pressure, the linear trend and inter-annual variability in the earth's gravity field, the global sea level rise, and the effects of post glacial rebound. The effects of mantle anelasticity on nutations, earth tides, and tidal variation in the lod was modeled. Results of this model can be used with Crustal Dynamics observations to look at the anelastic dissipation and dispersion at tidal periods. The effects of surface topography on various components of crustal deformation was also modeled, and numerical models were developed of post glacial rebound.

  14. The Trend of "Quasi-Religiosity" among Krasnoiarsk College Students

    ERIC Educational Resources Information Center

    Nemirovskii, V. G.; Starikov, P. A.

    2005-01-01

    This article is devoted to a study of the structure and dynamics of "quasi-religious" ideas in the everyday consciousness of Russian college students. What is meant by the term quasi-religiosity is a whole set of unsystematized ideas, the respondents' belief in idealistic concepts that are popular on the level of mass consciousness. The study's…

  15. Periodic and Quasi-Periodic Orbitsfor the Standard Map

    NASA Astrophysics Data System (ADS)

    Berretti, Alberto; Gentile, Guido

    We consider both periodic and quasi-periodic solutions for the standard map, and we study the corresponding conjugating functions, i.e. the functions conjugating the motions to trivial rotations. We compare the invariant curves with rotation numbers ω satisfying the Bryuno condition and the sequences of periodic orbits with rotation numbers given by their convergents ωN = pN/qN. We prove the following results for N--> ∞: (1) for rotation numbers ωNN we study the radius of convergence of the conjugating functions and we find lower bounds on them, which tend to a limit which is a lower bound on the corresponding quantity for ω (2) the periodic orbits consist of points which are more and more close to the invariant curve with rotation number ω (3) such orbits lie on analytical curves which tend uniformly to the invariant curve.

  16. Quality and safety in the transitional care of the elderly (phase 2): the study protocol of a quasi-experimental intervention study for a cross-level educational programme

    PubMed Central

    Storm, Marianne; Groene, Oliver; Testad, Ingelin; Dyrstad, Dagrunn N; Heskestad, Randi N; Aase, Karina

    2014-01-01

    Introduction Transitional care and patient handover are important areas to ensure quality and safety in elderly healthcare services. Previous studies showed that healthcare professionals have little knowledge of the setting they are transferring patients to and a limited understanding of roles and functions; these constitute barriers to effective communication and shared care responsibilities across levels of care. Aim The main objective is to implement a cross-level education-based intervention programme with healthcare professionals aimed at (1) increasing professionals’ awareness and competencies about quality and safety in the transitional care of the elderly; (2) creating a discussion platform for knowledge exchange and learning across levels and units of care and (3) improving patient safety culture, in particular, in transitional care. Methods and analysis A quasi-experimental control group study design with an intervention group and a control group; this includes a pretest, post-test and 1-year follow-up test assessment of patient safety culture. Qualitative data will be collected during the intervention programme and between the measurements. The study design will be beneficial for addressing the effects of the cross-level educational intervention programme on reports of patient safety culture and for addressing the feasibility of the intervention measures. Ethics and dissemination The study has been approved by the Regional Committees for Medical and Health Research Ethics in Norway, Ref. No. 2011/1978. The study is based on informed written consent; informants can withdraw from the study at any point in time. The results will be disseminated at research conferences, in peer review journals and through public presentations outside the scientific community. PMID:25082425

  17. Supergranulation rotation

    NASA Astrophysics Data System (ADS)

    Schou, Jesper; Beck, John G.

    2001-01-01

    Simple convection models estimate the depth of supergranulation at approximately 15,000 km which suggests that supergranules should rotate at the rate of the plasma in the outer 2% of the Sun by radius. Previous measurements (Snodgrass & Ulrich, 1990; Beck & Schou, 2000) found that supergranules rotate significantly faster than this, with a size-dependent rotation rate. We expand on previous work and show that the torsional oscillation signal seen in the supergranules tracks that obtained for normal modes. We also find that the amplitudes and lifetimes of the supergranulation are size dependent.

  18. Rotational Energy.

    ERIC Educational Resources Information Center

    Lockett, Keith

    1988-01-01

    Demonstrates several objects rolling down a slope to explain the energy transition among potential energy, translational kinetic energy, and rotational kinetic energy. Contains a problem from Galileo's rolling ball experiment. (YP)

  19. Solar rotation.

    NASA Astrophysics Data System (ADS)

    Dziembowski, W.

    Sunspot observations made by Johannes Hevelius in 1642 - 1644 are the first ones providing significant information about the solar differential rotation. In modern astronomy the determination of the rotation rate is done in a routine way by measuring positions of various structures on the solar surface as well as by studying the Doppler shifts of spectral lines. In recent years a progress in helioseismology enabled determination of the rotation rate in the layers inaccessible for direct observations. There are still uncertainties concerning, especially, the temporal variations of the rotation rate and its behaviour in the radiative interior. We are far from understanding the observations. Theoretical works have not yet resulted in a satisfactory model for the angular momentum transport in the convective zone.

  20. Enhanced low-level LSC performance for carbon-14 dating using a bismuth germanate (Bi{sub 4}Ge{sub 3}O{sub 12}) quasi-active guard

    SciTech Connect

    Cook, G.T.

    1995-12-31

    The Packard 2770TR/SL is a novel low-level liquid scintillation spectrometer which employs bismuth germanate (BGO - Bi{sub 4}Ge{sub 3}O{sub 12}) as a quasi-active guard to reduce background count rates and improve limits of detection. The results of this study indicate that this system shows tremendous potential for radiocarbon dating. Its great advantage is that it can give exceptional performance using standard low {sup 40}K borosilicate glass vials costing only a few cents each. For example, in an optimized counting window, 4.6-mL {sup 14}C benzene contained in a standard 7-mL glass vial produced a background count rate of 0.49 cpm and an efficiency of 70.3%, yielding a figure of merit (E{sup 2}V{sup 2}/B) value of 213,000 {+-}9,000 (where B = background count rate in counts per minute [cpm], E = percentage efficiency, and V = volume of benzene). This performance is comparable to published data for low-level instruments which employ active coincidence guard detectors and standard glass vials. When the same vials were recounted in vial holders, specially fabricated from BGO, the corresponding optimum values for background, efficiency and figure of merit, respectively, were 0.24 cpm, 61.0% and 328,000 {+-} 19,000. This performance is comparable to that of other low-level counting instruments when they are used in combination with specialized Teflon and silica vials. The BGO vial holders were also used in previous generations of Packard instruments which employ time resolved liquid scintillation counting (TR-LSC) for electronic background reduction and this resulted in significant improvements in performance.

  1. Observation of b2 symmetry vibrational levels of the SO2C 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

    SciTech Connect

    Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.

    2016-04-14

    Here, the C 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C state below 1600 cm–1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.

  2. Quasi-one-dimensional density of states in a single quantum ring

    PubMed Central

    Kim, Heedae; Lee, Woojin; Park, Seongho; Kyhm, Kwangseuk; Je, Koochul; Taylor, Robert A.; Nogues, Gilles; Dang, Le Si; Song, Jin Dong

    2017-01-01

    Generally confinement size is considered to determine the dimensionality of nanostructures. While the exciton Bohr radius is used as a criterion to define either weak or strong confinement in optical experiments, the binding energy of confined excitons is difficult to measure experimentally. One alternative is to use the temperature dependence of the radiative recombination time, which has been employed previously in quantum wells and quantum wires. A one-dimensional loop structure is often assumed to model quantum rings, but this approximation ceases to be valid when the rim width becomes comparable to the ring radius. We have evaluated the density of states in a single quantum ring by measuring the temperature dependence of the radiative recombination of excitons, where the photoluminescence decay time as a function of temperature was calibrated by using the low temperature integrated intensity and linewidth. We conclude that the quasi-continuous finely-spaced levels arising from the rotation energy give rise to a quasi-one-dimensional density of states, as long as the confined exciton is allowed to rotate around the opening of the anisotropic ring structure, which has a finite rim width. PMID:28053350

  3. Quasi-one-dimensional density of states in a single quantum ring

    NASA Astrophysics Data System (ADS)

    Kim, Heedae; Lee, Woojin; Park, Seongho; Kyhm, Kwangseuk; Je, Koochul; Taylor, Robert A.; Nogues, Gilles; Dang, Le Si; Song, Jin Dong

    2017-01-01

    Generally confinement size is considered to determine the dimensionality of nanostructures. While the exciton Bohr radius is used as a criterion to define either weak or strong confinement in optical experiments, the binding energy of confined excitons is difficult to measure experimentally. One alternative is to use the temperature dependence of the radiative recombination time, which has been employed previously in quantum wells and quantum wires. A one-dimensional loop structure is often assumed to model quantum rings, but this approximation ceases to be valid when the rim width becomes comparable to the ring radius. We have evaluated the density of states in a single quantum ring by measuring the temperature dependence of the radiative recombination of excitons, where the photoluminescence decay time as a function of temperature was calibrated by using the low temperature integrated intensity and linewidth. We conclude that the quasi-continuous finely-spaced levels arising from the rotation energy give rise to a quasi-one-dimensional density of states, as long as the confined exciton is allowed to rotate around the opening of the anisotropic ring structure, which has a finite rim width.

  4. Stellar rotation period inference with Gaussian processes

    NASA Astrophysics Data System (ADS)

    Angus, Ruth; Aigrain, Susanne; Foreman-Mackey, Daniel

    2016-10-01

    The light curves of spotted, rotating stars are often non-sinusoidal and Quasi-Periodic (QP) and a strictly periodic sinusoid is therefore not a representative generative model. Ideally, a physical model of the stellar surface would be conditioned on the data, however the parameters of such models can be highly degenerate.

  5. Rotational Orientation Effects in NO(X) + Ar Inelastic Collisions.

    PubMed

    Brouard, M; Chadwick, H; Gordon, S D S; Hornung, B; Nichols, B; Aoiz, F J; Stolte, S

    2015-12-17

    Rotational angular momentum orientation effects in the rotationally inelastic collisions of NO(X) with Ar have been investigated both experimentally and theoretically at a collision energy of 530 cm(-1). The collision-induced orientation has been determined experimentally using a hexapole electric field to select the ϵ = -1 Λ-doublet level of the NO(X) j = 1/2 initial state. Fully quantum state resolved polarization-dependent differential cross sections were recorded experimentally using a crossed molecular beam apparatus coupled with a (1 + 1') resonance-enhanced multiphoton ionization detection scheme and subsequent velocity-map imaging. To determine the NO sense of rotation, the probe radiation was circularly polarized. Experimental orientation polarization-dependent differential cross sections are compared with those obtained from quantum mechanical scattering calculations and are found to be in good agreement. The origin of the collision-induced orientation has been investigated by means of close-coupled quantum mechanical, quantum mechanical hard shell, quasi-classical trajectory (QCT), and classical hard shell calculations at the same collision energy. Although there is evidence for the operation of limiting classical mechanisms, the rotational orientation cannot be accounted for by QCT calculations and is found to be strongly influenced by quantum mechanical effects.

  6. Energy Spectra of Strongly Stratified and Rotating Turbulence

    NASA Technical Reports Server (NTRS)

    Mahalov, Alex; Nicolaenko, Basil; Zhou, Ye

    1998-01-01

    Turbulence under strong stratification and rotation is usually characterized as quasi-two dimensional turbulence. We develop a "quasi-two dimensional" energy spectrum which changes smoothly between the Kolmogorov -5/3 law (no stratification), the -2 scalings of Zhou for the case of strong rotation, as well as the -2 scalings for the case of strong rotation and stratification. For strongly stratified turbulence, the model may give the -2 scaling predicted by Herring; and the -5/3 scaling indicated by some mesoscale observations.

  7. Trends in the components of extreme water levels signal a rotation of winds in strong storms in the eastern Baltic Sea

    NASA Astrophysics Data System (ADS)

    Pindsoo, Katri; Soomere, Tarmo

    2016-04-01

    high water levels are different, vary markedly along the coast and provide a useful quantification of the vulnerability of single coastal segments with respect to coastal flooding. The formal linear trends in the extreme values of these water level components exhibit radically different spatial variations. The slopes of the trends in the weekly average are almost constant (~4 cm/decade for 8-day running average) along the entire eastern Baltic Sea coast. This first of all indicates that the duration of storm sequences has increased. The trends for maxima of local storm surge heights represent almost the entire spatial variability in the water level extremes. Their slopes are almost zero at the open Baltic Proper coasts of the Western Estonian archipelago. Therefore, an increase in wind speed in strong storms is unlikely in this area. In contrast, the slopes in question reach 5-7 cm/decade in the eastern Gulf of Finland and Gulf of Riga. This feature suggests that wind direction in strongest storms may have rotated in the northern Baltic Sea.

  8. Earth Rotation

    NASA Technical Reports Server (NTRS)

    Dickey, Jean O.

    1995-01-01

    The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

  9. Quasi-continuous magnets

    SciTech Connect

    Sims, J.R.; Naumovich, G.J.; Hoang, T.A.; Dent, P.C.

    1996-05-01

    The National High Magnetic Field Laboratory is completing a quasi-continuous magnet which will sustain a constant field of 60 T for 100 ms in a 32-mm 77 K bore. This magnet consists of 9 mechanically independent, nested, liquid nitrogen-cooled coils which are individually reinforced by high-strength stainless steel outer shells. The coils were wound from rectangular large cross-section, high-strength, high-conductivity copper conductor insulated wtih polyimide and fiberglass tapes. After winding, the coils were inserted into closely fitted, stainless steel reinforcing shells and impregnated with epoxy resin. Design, analysis, material, fabrication and operational issues for this class of magnets are reviewed. Fabrication and quality assurance testing of the 60 T coil set are covered in detail. Future growth of and possible links from this technology to other magnet systems are discussed. Needed improvements in design, analysis, materials, and fabrication are outlined.

  10. Effects of manure and mineral fertilization strategies on soil antibiotic resistance gene levels and microbial community in a paddy-upland rotation system.

    PubMed

    Lin, Hui; Sun, Wanchun; Zhang, Zulin; Chapman, Stephen J; Freitag, Thomas E; Fu, Jianrong; Zhang, Xin; Ma, Junwei

    2016-04-01

    This work investigated the responses of antibiotic resistance genes (ARGs) and the soil microbial community in a paddy-upland rotation system to mineral fertilizer (NPK) and different application dosages of manure combined with NPK. The occurrence of five tetracycline ARGs (tetA, tetB, tetC, tetG and tetW), two sulfonamide ARGs (sul1 and sul2) and one genetic element (IntI1) was quantified. NPK application showed only slight or no impact on soil ARGs abundances compared with the control without fertilizer. Soil ARGs abundances could be increased by manure-NPK application but was related to manure dosage (2250-9000 kg ha(-1)). Principal component analysis (PCA) showed that the soil ARG profile of the treatment with 9000 kg ha(-1) manure separated clearly from the other treatments; the ARGs that contributed most to the discrimination of this treatment were tetA, tetG, tetW, sul1, sul2 and IntI1. Community level physiological profile (CLPP) analysis showed that increasing manure dosage from 4500 kg ha(-1) to 9000 kg ha(-1) induced a sharp increase in almost all of the detected ARGs but would not change the microbial community at large. However, 9000 kg ha(-1) manure application produced a decline in soil microbial activity. Determination of antibiotics and heavy metals in soils suggested that the observed bloom of soil ARGs might associate closely with the accumulation of copper and zinc in soil.

  11. Rotational Spectrum of Sarin

    NASA Astrophysics Data System (ADS)

    Walker, A. R. Hight; Suenram, R. D.; Samuels, Alan; Jensen, James; Ellzy, Michael W.; Lochner, J. Michael; Zeroka, Daniel

    2001-05-01

    As part of an effort to examine the possibility of using molecular-beam Fourier-transform microwave spectroscopy to unambiguously detect and monitor chemical warfare agents, we report the first observation and assignment of the rotational spectrum of the nerve agent Sarin (GB) (Methylphosphonofluoridic acid 1-methyl-ethyl ester, CAS #107-44-8) at frequencies between 10 and 22 GHz. Only one of the two low-energy conformers of this organophosphorus compound (C4H10FO2P) was observed in the rotationally cold (Trot<2 K) molecular beam. The experimental asymmetric-rotor ground-state rotational constants of this conformer are A=2874.0710(9) MHz, B=1168.5776(4) MHz, C=1056.3363(4) MHz (Type A standard uncertainties are given, i.e., 1σ), as obtained from a least-squares analysis of 74 a-, b-, and c-type rotational transitions. Several of the transitions are split into doublets due to the internal rotation of the methyl group attached to the phosphorus. The three-fold-symmetry barrier to internal rotation estimated from these splittings is 677.0(4) cm-1. Ab initio electronic structure calculations using Hartree-Fock, density functional, and Moller-Plesset perturbation theories have also been made. The structure of the lowest-energy conformer determined from a structural optimization at the MP2/6-311G** level of theory is consistent with our experimental findings.

  12. Simulation of non-resonant internal kink mode with toroidal rotation in the National Spherical Torus Experiment

    SciTech Connect

    Wang, Feng; Liu, J. Y.; Fu, G. Y.; Breslau, J. A.; Tritz, Kevin

    2013-07-15

    Plasmas in spherical and conventional tokamaks, with weakly reversed shear q profile and minimum q above but close to unity, are susceptible to an non-resonant (m,n) = (1,1) internal kink mode. This mode can saturate and persist and can induce a (2,1) seed island for Neoclassical Tearing Mode. [Breslau et al. Nucl. Fusion 51, 063027 (2011)]. The mode can also lead to large energetic particle transport and significant broadening of beam-driven current. Motivated by these important effects, we have carried out extensive nonlinear simulations of the mode with finite toroidal rotation using parameters and profiles of an NTSX plasma with a weakly reversed shear profile. The numerical results show that, at the experimental level, plasma rotation has little effect on either equilibrium or linear stability. However, rotation can significantly influence the nonlinear dynamics of the (1,1) mode and the induced (2,1) magnetic island. The simulation results show that a rotating helical equilibrium is formed and maintained in the nonlinear phase at finite plasma rotation. In contrast, for non-rotating cases, the nonlinear evolution exhibits dynamic oscillations between a quasi-2D state and a helical state. Furthermore, the effects of rotation are found to greatly suppress the (2,1) magnetic island even at a low level.

  13. Torque Simulator for Rotating Systems

    NASA Technical Reports Server (NTRS)

    Davis, W. T.

    1982-01-01

    New torque brake simulates varying levels of friction in bearings of rotating body. Rolling-tail torque brake uses magnetic force to produce friction between rotating part and stationary part. Simulator electronics produce positive or negative feedback signal, depending on direction of rotation. New system allows for first time in-depth study of effects of tail-fin spin rates on pitch-, yaw-, and roll-control characteristics.

  14. On the absence of rotational levels for J{sup π}K = 0{sup +}0{sub 2} and 2{sup +}2{sub 2} nonrotational states in {sup 164}Dy and {sup 166}Er

    SciTech Connect

    Govor, L. I. Demidov, A. M.; Kurkin, V. A.; Mikhailov, I. V.

    2015-03-15

    Various reasons for the absence of rotational levels for J{sup π}K = 0{sup +}0{sub 2} and 2{sup +}2{sub 2} nonrotational states in {sup 164}Dy and {sup 166}Er are considered. Preference is given to the effect of the excitation of an anharmonic two-phonon state in pair vibrations of the superconducting type.

  15. Visualizing rotations and composition of rotations with the Rodrigues vector

    NASA Astrophysics Data System (ADS)

    Valdenebro, Angel G.

    2016-11-01

    The purpose of this paper is to show that the mathematical treatment of three-dimensional rotations can be simplified, and its geometrical understanding improved, using the Rodrigues vector representation. We present a novel geometrical interpretation of the Rodrigues vector. Based on this interpretation and simple geometrical considerations, we derive the Euler-Rodrigues formula, Cayley’s rotation formula and the composition law for finite rotations. The level of this discussion should be suitable for undergraduate physics or engineering courses where rotations are discussed.

  16. Quasi-particle structure of proton-hole cobalt isotopes

    NASA Astrophysics Data System (ADS)

    Gupta, Anuradha; Verma, Preeti; Singh, Suram; Bharti, Arun; Khosa, S. K.; Bhat, G. H.; Sheikh, J. A.

    2015-09-01

    Projected Shell Model calculations have been employed for the description of the ground band in odd mass 57-67Co isotopes. In the present work, quadrupole and monopole pairing interactions as well as quadrupole-quadrupole interactions are effectively included in the Hamiltonian for obtaining various nuclear structure properties using the angular momentum projection technique. The yrast spectra of these isotopes are described as interplay between the angular momentum projected states around the Fermi level. The quasi-particle structure of these nuclei is found to be comprised of different intrinsic K-quantum numbers. Rotational alignments in terms of kinetic moment of inertia (ℑ (1)) have also been discussed. The electromagnetic transition probabilities [ B (E2) and B (M1)] are also obtained in the present work and are found to be in good agreement with the available experimental as well as the other theoretical data, which tests the consistency of the applied projected shell model. The present PSM calculations also report the existence of low lying deformed structure along with the spherical structure at N = 40.

  17. OH "Rotational" Temperatures

    NASA Astrophysics Data System (ADS)

    Slanger, T. G.; Matsiev, D.

    2015-12-01

    It is customary to determine temperatures in the mesosphere and MLT by using Boltzmann plots based on the distributions of the lowest rotational levels in the bands of the OH Meinel system, assuming that populations in these levels are in LTE with the kinetic temperature. The higher rotational levels are clearly not in LTE, and using sky spectra from the large telescopes (Keck, VLT) has now shown that this assumption is invalid even for low rotational levels [Cosby and Slanger, 2007; Noll et al. 2014]. The apparent temperatures derived from such Boltzmann plots show an upward trend with increasing OH vibrational level, from v = 2 to v = 9, with reproducible structure such that there is always a peak at v = 8. Over this range of vibrational levels, the "temperature" increase with increasing altitude is on the order of 15-20 K. At the same time, the modeled kinetic temperature is decreasing, as the OH layer lies below the mesopause, and rocket/satellite measurements indicate that the highest levels have the highest altitude. Since this technique of kinetic temperature assessment has been in use for many years, it is important to realize that the procedure is flawed, most likely due to the details of the relaxation processes of OH(v).

  18. A comparative study of rapidly and slowly rotating dynamical regimes in a terrestrial general circulation model

    NASA Technical Reports Server (NTRS)

    Del Genio, Anthony D.; Suozzo, Robert J.

    1987-01-01

    As a preliminary step in the development of a general circulation model for general planetary use, a simplified vesion of thef GISS Model I GCM has been run at various rotation periods to investigate differences between the dynamical regimes of rapidly and slowly rotating planets. To isolate the dynamical processes, the hydrologic cycle is suppressed and the atmosphere is forced with perpetual annual mean solar heating. All other parameters except the rotation period remain fixed at their terrestrial values. Experiments were conducted for rotation periods of 2/3, 1, 2, 4, 8, 16, 64 and 256 days. The results are in qualitative agreement with similar experiments carried out previously with other GCMs and with certain aspects of one Venus GCM simulation. As rotation rate decreases, the energetics shifts from baroclinc to quasi-barotropic when the Rossby radius of deformation reaches planetary scale. The Hadley cell expands poleward and replaces eddies as the primary mode of large-scale heat transport. Associated with this is a poleward shift of the baroclinic zone and jet stream and a reduction of the equator-pole temperature contrast. Midlatitude jet strength peaks at 8 days period, as does the weak positive equatorial zonal wind which occurs at upper levels at all rotation periods. Eddy momentum transport switches from poleward to equatorward at the same period. Tropospheric mean static stability generally increases in the tropics and decreases in midlatitudes as rotation rate decreases, but the global mean static stability is independent of rotation rate. The peak in the eddy kinetic energy spectrum shifts toward lower wavenumbers, reaching wavenumber 1 at a period of 8 days. Implications of these results for the dynamics of Venus and Titan are discussed. Specifically, it is suggested that the extent of low-level convection determines whether the Gierasch mechanism contributes significantly to equatorial superrotation on these planets.

  19. Multigrid solutions to quasi-elliptic schemes

    NASA Technical Reports Server (NTRS)

    Brandt, A.; Taasan, S.

    1985-01-01

    Quasi-elliptic schemes arise from central differencing or finite element discretization of elliptic systems with odd order derivatives on non-staggered grids. They are somewhat unstable and less accurate then corresponding staggered-grid schemes. When usual multigrid solvers are applied to them, the asymptotic algebraic convergence is necessarily slow. Nevertheless, it is shown by mode analyses and numerical experiments that the usual FMG algorithm is very efficient in solving quasi-elliptic equations to the level of truncation errors. Also, a new type of multigrid algorithm is presented, mode analyzed and tested, for which even the asymptotic algebraic convergence is fast. The essence of that algorithm is applicable to other kinds of problems, including highly indefinite ones.

  20. Numerical investigation of the Earth's rotation during a complete precession cycle

    NASA Technical Reports Server (NTRS)

    Richardson, David L.

    1992-01-01

    A theory for the long-term rotational motion of the quasi-rigid Earth was constructed by numerical integration. The theory spans 72,000 years centered about 1968 A.D., and provides accurate rotational and positional data for the Earth in the recent past and the near future. The physical model is termed dynamically consistent because developments for the active forces and torques are truncated based solely on their magnitudes regardless of their origin. The model includes all appropriate forces and torques due to the geopotential and tidal effects as well as lunisolar and planetary contributions. The elastic and inelastic deformations due to tidal action were too small to affect the mass properties of the Earth at the truncation level of the model. However, long-term dissipative effects of the tidal forces and torques were not negligible. These considerations gave the model its quasi-rigid characterization. The numerical output provided both rotational and orbital-element data. The data were fitted throughout the 72,000-year range using Chebyshev polynomial series.

  1. Quasi-optical constrained lens amplifiers

    NASA Astrophysics Data System (ADS)

    Schoenberg, Jon S.

    1995-09-01

    A major goal in the field of quasi-optics is to increase the power available from solid state sources by combining the power of individual devices in free space, as demonstrated with grid oscillators and grid amplifiers. Grid amplifiers and most amplifier arrays require a plane wave feed, provided by a far field source or at the beam waist of a dielectric lens pair. These feed approaches add considerable loss and size, which is usually greater than the quasi-optical amplifier gain. In addition, grid amplifiers require external polarizers for stability, further increasing size and complexity. This thesis describes using constrained lens theory in the design of quasi optical amplifier arrays with a focal point feed, improving the power coupling between the feed and the amplifier for increased gain. Feed and aperture arrays of elements, input/output isolation and stability, amplifier circuitry, delay lines and bias distribution are all contained on a single planar substrate, making monolithic circuit integration possible. Measured results of X band transmission lenses and a low noise receive lens are presented, including absolute power gain up to 13 dB, noise figure as low as 1.7 dB, beam scanning to +/-30 deg, beam forming and beam switching of multiple sources, and multiple level quasi-optical power combining. The design and performance of millimeter wave power combining amplifier arrays is described, including a Ka Band hybrid array with 1 watt output power, and a V Band 36 element monolithic array with a 5 dB on/off ratio.

  2. Visualizing Compound Rotations with Virtual Reality

    ERIC Educational Resources Information Center

    Flanders, Megan; Kavanagh, Richard C.

    2013-01-01

    Mental rotations are among the most difficult of all spatial tasks to perform, and even those with high levels of spatial ability can struggle to visualize the result of compound rotations. This pilot study investigates the use of the virtual reality-based Rotation Tool, created using the Virtual Reality Modeling Language (VRML) together with…

  3. SUBMILLIMETER QUASI-PERIODIC OSCILLATIONS IN MAGNETICALLY CHOKED ACCRETION FLOW MODELS OF SgrA*

    SciTech Connect

    Shcherbakov, Roman V.; McKinney, Jonathan C.

    2013-09-10

    High-frequency quasi-periodic oscillations (QPOs) appear in general-relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around rapidly rotating black holes (BHs). We perform polarized radiative transfer calculations with the ASTRORAY code to explore the manifestations of these QPOs for SgrA*. We construct a simulation-based model of a radiatively inefficient accretion flow and find model parameters by fitting the mean polarized source spectrum. The simulated QPOs have a total submillimeter flux amplitude up to 5% and a linearly polarized flux amplitude up to 2%. The oscillations reach high levels of significance 10{sigma}-30{sigma} and high-quality factors Q Almost-Equal-To 5. The oscillation period T Almost-Equal-To 100 M Almost-Equal-To 35 minutes corresponds to the rotation period of the BH magnetosphere that produces a trailing spiral in resolved disk images. The total flux signal is significant over noise for all tested frequencies 87 GHz, 230 GHz, and 857 GHz and inclination angles 10 Degree-Sign , 37 Degree-Sign , and 80 Degree-Sign . The non-detection in the 230 GHz SubMillimeter Array light curve is consistent with a low signal level and a low sampling rate. The presence of submillimeter QPOs in SgrA* will be better tested with the Atacama Large Millimeter Array.

  4. Vortex structures of rotating Bose-Einstein condensates in an anisotropic harmonic potential

    SciTech Connect

    Matveenko, S. I.

    2010-09-15

    We found an analytical solution for the vortex structure in a rapidly rotating trapped Bose-Einstein condensate in the lowest Landau level approximation. This solution is exact in the limit of a large number of vortices and is obtained for the case of a condensate in a anisotropic harmonic potential. The solution describes as limiting cases both a triangle vortex lattice in the symmetric potential trap and a quasi-one-dimensional structure of vortex rows in an asymmetric case, when the rotation frequency is very close to the lower trapping potential frequency. The shape of the density profile is found to be close to the Thomas-Fermi inverted paraboloid form, except in the vicinity of edges of a condensate cloud.

  5. Quasi-classical trajectories study of Ne79Br2(B) vibrational predissociation.

    PubMed

    González-Martínez, M L; Rubayo-Soneira, J; Janda, K

    2006-10-21

    A full-dimensional quasi-classical trajectories study on the vibrational predissociation (VP) of the Ne79Br2(B) complex is presented. Following the most recent experiments, the Br2(B) vibrational levels v'=16-29 were explored. The total angular momentum, J, was taken to be zero, and a semiclassical Franck-Condon model to compute initial conditions from quantum distributions was employed. Predissociation lifetimes were extracted from Ne79Br2 population decay by using two different exponential laws. Predicted lifetimes are in excellent agreement with the last experimental results [J. A. Cabrera, C. R. Bieler, B. C. Olbricht, W. E. van der Veer and K. C. Janda, J. Chem. Phys., 2005, 123, 054311]. The Br2 fragment ro-vibrational distributions resulting from the VP of the molecule were obtained from the statistics of classical magnitudes using the standard binning procedure. Computed rotational distributions (for the Deltav'=-1, -2 channels) are also in very good agreement with the experimental results [M. Nejad-Sattari and T. A. Stephenson, J. Chem. Phys., 1997, 106 5454]. The influence of two quantum effects-the closing of the Deltav'=-1 dissociation channel and the intramolecular vibrational relaxation (IVR) mechanism-on the agreement with experimental rotational distributions, is discussed. Due to the classical character of our calculations and the binning procedure we used, the agreement of computed vibrational distributions with experimental and quantum theoretical is qualitative. For instance, for v'=28-for which the Deltav'=-1 channel is experimentally found to be closed-the Deltav'=-2 channel becomes statistically more significant. A discussion on the viability of similar quasi-classical methods to model the VP dynamics of analogous clusters is presented.

  6. KEPLER RAPIDLY ROTATING GIANT STARS

    SciTech Connect

    Costa, A. D.; Martins, B. L. Canto; Bravo, J. P.; Paz-Chinchón, F.; Chagas, M. L. das; Leão, I. C.; Oliveira, G. Pereira de; Silva, R. Rodrigues da; Roque, S.; Oliveira, L. L. A. de; Silva, D. Freire da; De Medeiros, J. R.

    2015-07-10

    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of substellar companions by their hosting stars. In the present Letter, we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time, the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting a very short rotation period with values ranging from 13 to 55 days. This finding points to remarkable surface rotation rates, up to 18 times the rotation of the Sun. These giants are combined with six others recently listed in the literature for mid-infrared (IR) diagnostics based on Wide-field Infrared Survey Explorer information, from which a trend for an IR excess is revealed for at least one-half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  7. Quasi-biennial oscillation above 10 mb

    SciTech Connect

    Baldwin, M.P. Dunkerton, T.J. )

    1991-07-01

    It is shown that the quasi-biennial oscillation of the equatorial lower stratosphere was correlated with mean zonal wind in the upper stratosphere, 1979-90. Correlations were positive near 60{degree}N and 30{degree}S during northern hemisphere (NH) winter and negative in the equatorial upper stratosphere during all seasons. Spatial autocorrelation of mean zonal wind during NH winter was actually largest in the upper stratosphere, between 10{degree}S and 62{degree}N, due to strong coupling between tropical and extratropical flow at upper levels.

  8. Energy Transfer in Rotating Turbulence

    NASA Technical Reports Server (NTRS)

    Cambon, Claude; Mansour, Nagi N.; Godeferd, Fabien S.; Rai, Man Mohan (Technical Monitor)

    1995-01-01

    The influence or rotation on the spectral energy transfer of homogeneous turbulence is investigated in this paper. Given the fact that linear dynamics, e.g. the inertial waves regime tackled in an RDT (Rapid Distortion Theory) fashion, cannot Affect st homogeneous isotropic turbulent flow, the study of nonlinear dynamics is of prime importance in the case of rotating flows. Previous theoretical (including both weakly nonlinear and EDQNM theories), experimental and DNS (Direct Numerical Simulation) results are gathered here and compared in order to give a self-consistent picture of the nonlinear effects of rotation on tile turbulence. The inhibition of the energy cascade, which is linked to a reduction of the dissipation rate, is shown to be related to a damping due to rotation of the energy transfer. A model for this effect is quantified by a model equation for the derivative-skewness factor, which only involves a micro-Rossby number Ro(sup omega) = omega'/(2(OMEGA))-ratio of rms vorticity and background vorticity as the relevant rotation parameter, in accordance with DNS and EDQNM results fit addition, anisotropy is shown also to develop through nonlinear interactions modified by rotation, in an intermediate range of Rossby numbers (Ro(omega) = (omega)' and Ro(omega)w greater than 1), which is characterized by a marco-Rossby number Ro(sup L) less than 1 and Ro(omega) greater than 1 which is characterized by a macro-Rossby number based on an integral lengthscale L and the micro-Rossby number previously defined. This anisotropy is mainly an angular drain of spectral energy which tends to concentrate energy in tile wave-plane normal to the rotation axis, which is exactly both the slow and the two-dimensional manifold. In Addition, a polarization of the energy distribution in this slow 2D manifold enhances horizontal (normal to the rotation axis) velocity components, and underlies the anisotropic structure of the integral lengthscales. Finally is demonstrated the

  9. Quasi-periodic continuation along a continuous symmetry

    NASA Astrophysics Data System (ADS)

    Salomone, Matthew David

    Given a system of differential equations which admits a continuous group of symmetries and possesses a periodic solution, we show that under certain nondegeneracy assumptions there always exists a continuous family containing infinitely many periodic and quasi-periodic trajectories. This generalizes the continuation method of Poincaré to orbits which are not necessarily periodic. We apply these results in the setting of the Lagrangian N -body problem of homogeneous potential to characterize an infinite family of rotating nonplanar "hip-hop" orbits in the four-body problem of equal masses, and show how some other trajectories in the N -body theory may be extended to infinite families of periodic and quasi-periodic trajectories.

  10. The breakdown of the anelastic approximation in rotating compressible convection: implications for astrophysical systems

    PubMed Central

    Calkins, Michael A.; Julien, Keith; Marti, Philippe

    2015-01-01

    The linear theory for rotating compressible convection in a plane layer geometry is presented for the astrophysically relevant case of low Prandtl number gases. When the rotation rate of the system is large, the flow remains geostrophically balanced for all stratification levels investigated and the classical (i.e. incompressible) asymptotic scaling laws for the critical parameters are recovered. For sufficiently small Prandtl numbers, increasing stratification tends to further destabilize the fluid layer, decrease the critical wavenumber and increase the oscillation frequency of the convective instability. In combination, these effects increase the relative magnitude of the time derivative of the density perturbation contained in the conservation of mass equation to non-negligible levels; the resulting convective instabilities occur in the form of compressional quasi-geostrophic oscillations. We find that the anelastic equations, which neglect this term, cannot capture these instabilities and possess spuriously growing eigenmodes in the rapidly rotating, low Prandtl number regime. It is shown that the Mach number for rapidly rotating compressible convection is intrinsically small for all background states, regardless of the departure from adiabaticity. PMID:25792951

  11. Rotational Energy Levels and Line Intensities for 2S+1Sigma-2S+1Sigma Transitions in an Open-Shell Diatomic Molecule Weakly Bonded to a Closed-Shell Partner.

    PubMed

    Fawzy

    1998-09-01

    This paper concerns rotational energy levels and line intensities for electronic, vibrational, and microwave transitions in an open-shell complex consisting of an open-shell diatomic molecule and a closed-shell partner. The electronic state of the open-shell diatomic fragment is a 2S+1Sigma state, where S >/= 12, the close-shell partner could be a rare gas atom or a diatomic molecule or a planar polyatomic molecule. We are considering a near-rigid rotor model for a nonlinear complex, taking into account thoroughly all effects of the electron spin and the quartic centrifugal distortion correction terms. The total Hamiltonian is expressed as H=Hrot+Hsr+Hss+Hcd+Hsrcd+Hsscd. We have derived all the nonvanishing matrix elements of the Hamiltonian operators in the molecular basis set. The rotational energy levels are calculated by numerical diagonalization of the total Hamiltonian matrix for each J value. The nonvanishing matrix elements of the electric dipole moment operator are derived in the molecular basis set for electronic, vibrational, and microwave transitions within the complex. Expectation values of the quantum numbers and of the parities of the rotational states are derived in the molecular basis set. Relative intensities of the allowed rotational transitions, expectation values of the quantum numbers and the parities are calculated numerically in the space of the eigenvectors obtained from diagonalization of the Hamiltonian matrix. The formalism and the computer program of this paper are considered as extensions to our previous work [W. M. Fawzy and J. T. Hougen, J. Mol. Spectrosc. 137, 154-165 (1989); W. M. Fawzy, J. Mol. Spectrosc. 160, 84-96 (1993)] and are expected to be particularly useful for analyzing and fitting high-resolution spectra of weakly bonded oxygen complexes. A brief discussion of the Hamiltonian operators, the matrix elements, and the computer program is given. Copyright 1998 Academic Press.

  12. Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis

    SciTech Connect

    Sokaras, D.; Zarkadas, Ch.; Fliegauf, R.; Beckhoff, B.; Karydas, A. G.

    2012-12-15

    We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. 'Demokritos,' Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current ({approx}{mu}A) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon K{alpha}. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented.

  13. New Classes of Quasi-Axisymmetric Stellarator Configurations

    SciTech Connect

    Ku LP, Garabedian PR

    2005-10-03

    We have identified and developed new classes of quasi-axially symmetric configurations which have attractive properties from the standpoint of both near-term physics experiments and long-term power producing reactors. These new configurations were developed as a result of surveying the aspect ratio-rotational transform space to identify regions endowed with particularly interesting features. These include configurations with very small aspect ratios ({approx}2.5) having superior quasi-symmetry and energetic particle confinement characteristics, and configurations with strongly negative global magnetic shear from externally supplied rotational transforms so that the overall rotational transform, when combined with the transform from bootstrap currents at finite plasma pressures, will yield a small but positive shear, making the avoidance of low order rational surfaces at a given operating beta possible. Additionally, we have found configurations with NCSX-like characteristics but with the biased components in the magnetic spectrum that allow us to improve the confinement of energetic particles. For each new class of configurations, we have designed coils as well to ensure that the new configurations are realizable and engineering-wise feasible. The coil designs typically have coil aspect ratios R/{Delta}{sub min}(C-P) {le} 6 and coil separation ratios R/{Delta}{sub min}(C-C) {le} 10, where R is the plasma major radius, {Delta}{sub min}(C-P) and {Delta}{sub min}(C-C) are the minimum coil to plasma and coil to coil separations, respectively. These coil properties allow power producing reactors be designed with major radii less than 9 meters for DT plasmas with a full breeding blanket. The good quasi-axisymmetry limits the energy loss of {alpha} particles to below 10%.

  14. Quasi-Linear Circuit

    NASA Technical Reports Server (NTRS)

    Bradley, William; Bird, Ross; Eldred, Dennis; Zook, Jon; Knowles, Gareth

    2013-01-01

    This work involved developing spacequalifiable switch mode DC/DC power supplies that improve performance with fewer components, and result in elimination of digital components and reduction in magnetics. This design is for missions where systems may be operating under extreme conditions, especially at elevated temperature levels from 200 to 300 degC. Prior art for radiation-tolerant DC/DC converters has been accomplished utilizing classical magnetic-based switch mode converter topologies; however, this requires specific shielding and component de-rating to meet the high-reliability specifications. It requires complex measurement and feedback components, and will not enable automatic re-optimization for larger changes in voltage supply or electrical loading condition. The innovation is a switch mode DC/DC power supply that eliminates the need for processors and most magnetics. It can provide a well-regulated voltage supply with a gain of 1:100 step-up to 8:1 step down, tolerating an up to 30% fluctuation of the voltage supply parameters. The circuit incorporates a ceramic core transformer in a manner that enables it to provide a well-regulated voltage output without use of any processor components or magnetic transformers. The circuit adjusts its internal parameters to re-optimize its performance for changes in supply voltage, environmental conditions, or electrical loading at the output

  15. Equatorial symmetry of Boussinesq convective solutions in a rotating spherical shell allowing rotation of the inner and outer spheres

    SciTech Connect

    Kimura, Keiji; Takehiro, Shin-ichi; Yamada, Michio

    2014-08-15

    We investigate properties of convective solutions of the Boussinesq thermal convection in a moderately rotating spherical shell allowing the respective rotation of the inner and outer spheres due to the viscous torque of the fluid. The ratio of the inner and outer radii of the spheres, the Prandtl number, and the Taylor number are fixed to 0.4, 1, and 500{sup 2}, respectively. The Rayleigh number is varied from 2.6 × 10{sup 4} to 3.4 × 10{sup 4}. In this parameter range, the behaviours of obtained asymptotic convective solutions are almost similar to those in the system whose inner and outer spheres are restricted to rotate with the same constant angular velocity, although the difference is found in the transition process to chaotic solutions. The convective solution changes from an equatorially symmetric quasi-periodic one to an equatorially symmetric chaotic one, and further to an equatorially asymmetric chaotic one, as the Rayleigh number is increased. This is in contrast to the transition in the system whose inner and outer spheres are assumed to rotate with the same constant angular velocity, where the convective solution changes from an equatorially symmetric quasi-periodic one, to an equatorially asymmetric quasi-periodic one, and to equatorially asymmetric chaotic one. The inner sphere rotates in the retrograde direction on average in the parameter range; however, it sometimes undergoes the prograde rotation when the convective solution becomes chaotic.

  16. Coronal hole differential rotation rate observed with SWICS/Ulysses

    NASA Astrophysics Data System (ADS)

    Zurbuchen, Th.; Bochsler, P.; von Steiger, R.

    1996-07-01

    We discuss the latitude variation of the coronal hole differential rotation investigating persistent structures in high speed streams as observed from SWICS Ulysses during its first passage of the southern polar hole in 1993-1994. We find a slower rotation rate near the ecliptic than what is inferred from averaged photospheric features, e.g. from sunspots. At intermediate latitudes we find a rate similar to the equatorial rotation rate indicating a quasi-rigid rotation of the polar coronal hole. At latitudes >65° no persistent structures to determine the polar rotation have been observed. For the passage of the southern heliosphere in 1993/94 we find a latitudinal dependence of the sidereal rotation rate of the coronal hole which can be approximated by ωSW=[13.13+1.94 sin2(Θ)]°/day, where Θ denotes the solar latitude.

  17. Renormalized vacuum polarization of rotating black holes

    NASA Astrophysics Data System (ADS)

    Ferreira, Hugo R. C.

    2015-04-01

    Quantum field theory on rotating black hole spacetimes is plagued with technical difficulties. Here, we describe a general method to renormalize and compute the vacuum polarization of a quantum field in the Hartle-Hawking state on rotating black holes. We exemplify the technique with a massive scalar field on the warped AdS3 black hole solution to topologically massive gravity, a deformation of (2 + 1)-dimensional Einstein gravity. We use a "quasi-Euclidean" technique, which generalizes the Euclidean techniques used for static spacetimes, and we subtract the divergences by matching to a sum over mode solutions on Minkowski spacetime. This allows us, for the first time, to have a general method to compute the renormalized vacuum polarization, for a given quantum state, on a rotating black hole, such as the physically relevant case of the Kerr black hole in four dimensions.

  18. IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part IV. Energy levels and transition wavenumbers for D216O, D217O, and D218O

    NASA Astrophysics Data System (ADS)

    Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Dénes, Nóra; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Hu, Shui-Ming; Szidarovszky, Tamás; Vasilenko, Irina A.

    2014-07-01

    This paper is the fourth of a series of papers reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependences, and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. This paper presents energy level and transition data for the following doubly and triply substituted isotopologues of water: D216O, D217O, and D218O. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure is used to determine the levels, the lines, and their self-consistent uncertainties for the spectral regions 0-14 016, 0-7969, and 0-9108 cm-1 for D216O, D217O, and D218O, respectively. For D216O, D217O, and D218O, 53 534, 600, and 12 167 lines are considered, respectively, from spectra recorded in absorption at room temperature and in emission at elevated temperatures. The number of validated energy levels is 12 269, 338, and 3351 for D216O, D217O, and D218O, respectively. The energy levels have been checked against the ones determined, with an average accuracy of about 0.03 cm-1, from variational rovibrational computations employing exact kinetic energy operators and an accurate potential energy surface. Furthermore, the rovibrational labels of the energy levels have been validated by an analysis of the computed wavefunctions using the rigid-rotor decomposition (RRD) scheme. The extensive list of MARVEL lines and levels obtained is deposited in the Supplementary Material of this paper, in a distributed information system applied to water, W@DIS, and on the official MARVEL website, where they can easily be retrieved.

  19. Graphical Models for Quasi-Experimental Designs

    ERIC Educational Resources Information Center

    Kim, Yongnam; Steiner, Peter M.; Hall, Courtney E.; Su, Dan

    2016-01-01

    Experimental and quasi-experimental designs play a central role in estimating cause-effect relationships in education, psychology, and many other fields of the social and behavioral sciences. This paper presents and discusses the causal graphs of experimental and quasi-experimental designs. For quasi-experimental designs the authors demonstrate…

  20. Large-scale quasi-geostrophic magnetohydrodynamics

    SciTech Connect

    Balk, Alexander M.

    2014-12-01

    We consider the ideal magnetohydrodynamics (MHD) of a shallow fluid layer on a rapidly rotating planet or star. The presence of a background toroidal magnetic field is assumed, and the 'shallow water' beta-plane approximation is used. We derive a single equation for the slow large length scale dynamics. The range of validity of this equation fits the MHD of the lighter fluid at the top of Earth's outer core. The form of this equation is similar to the quasi-geostrophic (Q-G) equation (for usual ocean or atmosphere), but the parameters are essentially different. Our equation also implies the inverse cascade; but contrary to the usual Q-G situation, the energy cascades to smaller length scales, while the enstrophy cascades to the larger scales. We find the Kolmogorov-type spectrum for the inverse cascade. The spectrum indicates the energy accumulation in larger scales. In addition to the energy and enstrophy, the obtained equation possesses an extra (adiabatic-type) invariant. Its presence implies energy accumulation in the 30° sector around zonal direction. With some special energy input, the extra invariant can lead to the accumulation of energy in zonal magnetic field; this happens if the input of the extra invariant is small, while the energy input is considerable.

  1. Leveling

    USGS Publications Warehouse

    1966-01-01

    Geodetic leveling by the U.S. Geological Survey provides a framework of accurate elevations for topographic mapping. Elevations are referred to the Sea Level Datum of 1929. Lines of leveling may be run either with automatic or with precise spirit levels, by either the center-wire or the three-wire method. For future use, the surveys are monumented with bench marks, using standard metal tablets or other marking devices. The elevations are adjusted by least squares or other suitable method and are published in lists of control.

  2. Bioreactor rotating wall vessel

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells.

  3. Cylindrical quasi-Gaussian beams.

    PubMed

    Mitri, F G

    2013-11-15

    Making use of the complex-source-point method in cylindrical coordinates, an exact solution representing a cylindrical quasi-Gaussian beam of arbitrary waist w(0) satisfying both the Helmholtz and Maxwell's equations is introduced. The Cartesian components of the electromagnetic field are derived stemming from different polarizations of the magnetic and electric vector potentials based on Maxwell's vectorial equations and Lorenz's gauge condition, without any approximations. Computations illustrate the theory for tightly focused and quasi-collimated cylindrical beams. The results are particularly useful in beam-forming design using high-aperture or collimated cylindrical laser beams in imaging microscopy, particle manipulation, optical tweezers, and the study of scattering, radiation forces, and torque on cylindrical structures.

  4. Internal rotation of γ Doradus stars

    NASA Astrophysics Data System (ADS)

    Ouazzani, R.-M.; Salmon, S. J. A. J.; Antoci, V.; Bedding, T. R.; Murphy, S. J.

    2016-12-01

    Thanks to the exquisite Kepler data, resulting from four years of quasi-continuous photometric observations, we are now able to use g-modes in order to reveal the internal structure of γ Doradus stars. In particular, it is now possible to detect series of g-modes with non-uniform period spacing, which carry the signature of internal rotation. In a theoretical work published earlier this year, we have defined a new seismic diagnostic for rotation in the γ Doradus stars that are rotating too rapidly to present rotational splitting. It is based on a new observable that is the slope of the period spacing when plotted againt the period. Here we recall the one-to-one relation between this observable and the internal rotation rate. We explain how it can be used without any additional constraint in order to retreive the rotation rate in the cavity probed by the observed g-modes. Finally we evaluate the uncertainty induced by the use of the asymptotic formulation of the traditional approximation, and we give a word of caution concerning retrograde modes.

  5. Broadband Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  6. Ideal statistically quasi Cauchy sequences

    NASA Astrophysics Data System (ADS)

    Savas, Ekrem; Cakalli, Huseyin

    2016-08-01

    An ideal I is a family of subsets of N, the set of positive integers which is closed under taking finite unions and subsets of its elements. A sequence (xk) of real numbers is said to be S(I)-statistically convergent to a real number L, if for each ɛ > 0 and for each δ > 0 the set { n ∈N :1/n | { k ≤n :| xk-L | ≥ɛ } | ≥δ } belongs to I. We introduce S(I)-statistically ward compactness of a subset of R, the set of real numbers, and S(I)-statistically ward continuity of a real function in the senses that a subset E of R is S(I)-statistically ward compact if any sequence of points in E has an S(I)-statistically quasi-Cauchy subsequence, and a real function is S(I)-statistically ward continuous if it preserves S(I)-statistically quasi-Cauchy sequences where a sequence (xk) is called to be S(I)-statistically quasi-Cauchy when (Δxk) is S(I)-statistically convergent to 0. We obtain results related to S(I)-statistically ward continuity, S(I)-statistically ward compactness, Nθ-ward continuity, and slowly oscillating continuity.

  7. Spin quasi-distribution functions

    NASA Astrophysics Data System (ADS)

    Scully, M. O.; Wódkiewicz, K.

    1994-01-01

    Two-classes of phase-space spin quasi-distribution functions are introduced and discussed. The first class of these distributions is based on the delta function construction. It is shown that such a construction can be carried out for an arbitrary spin s and an arbitrary ordering of the spin operators. The second class of the spin distributions is constructed with the help of the spin coherent states. The connection of the spin coherent states to the Stratonovich formalism is established and discussed. It is shown that the c-number phase-space description of quantum fluctuations provides a simple statistical picture of quantum fluctuations of spinoperators in terms of random directions on a unit sphere. For quantum states of the spin system the statistics of these random orientations is given by non-positive spin quasi-distribution functions. It is shown that the application of these spin quasi-distribution functions to the Einstein-Podolsky-Rosen correlations provide an insight into the quantum theory of measurement.

  8. A 20-dB quasi-integrated horn antenna

    NASA Technical Reports Server (NTRS)

    Eleftheriades, George V.; Ali-Ahmad, Walid Y.; Rebeiz, Gabriel M.

    1992-01-01

    A multimode quasi-integrated dipole-fed horn antenna is presented with a performance comparable to that of waveguide-fed corrugated horn antennas. The antenna has been designed using fullwave analysis and has been fabricated and tested at 91 GHz. The horn has a gain of 20 dB with very symmetric patterns, a Gaussian coupling efficiency of 97 percent, and a cross-polarization level of -22.7 dB. The antenna provides a significant improvement in integrated antenna designs and is suitable for millimeter-wave communication and radar systems and as a Gaussian-beam launcher in quasi-optical receiver systems.

  9. Solar generated quasi-biennial geomagnetic variation

    NASA Technical Reports Server (NTRS)

    Sugiura, M.; Poros, D. J.

    1977-01-01

    The existence of highly correlated quasi-biennial variations in the geomagnetic field and in solar activity is demonstrated. The analysis uses a numerical filter technique applied to monthly averages of the geomagnetic horizontal component and of the Zurich relative sunspot number. Striking correlations are found between the quasi-biennial geomagnetic variations determined from several magnetic observatories located at widely different longitudes, indicating a worldwide nature of the obtained variation. The correlation coefficient between the filtered Dst index and the filtered relative sunspot number is found to be -0.79 at confidence level greater than 99% with a time-lag of 4 months, with solar activity preceding the Dst variation. The correlation between the unfiltered data of Dst and of the sunspot number is also high with a similar time-lag. Such a timelag has not been discussed in the literature, and a further study is required to establish the mode of sun-earth relationship that gives this time delay.

  10. Proposal for fabrication-tolerant SOI polarization splitter-rotator based on cascaded MMI couplers and an assisted bi-level taper

    PubMed Central

    Wang, Jing; Qi, Minghao; Xuan, Yi; Huang, Haiyang; Li, You; Li, Ming; Chen, Xin; Jia, Qi; Sheng, Zhen; Wu, Aimin; Li, Wei; Wang, Xi; Zou, Shichang; Gan, Fuwan

    2014-01-01

    A novel silicon-on-insulator (SOI) polarization splitter-rotator (PSR) with a large fabrication tolerance is proposed based on cascaded multimode interference (MMI) couplers and an assisted mode-evolution taper. The tapers are designed to adiabatically convert the input TM0 mode into the TE1 mode, which will output as the TE0 mode after processed by the subsequent MMI mode converter, 90-degree phase shifter (PS) and MMI 3 dB coupler. The numerical simulation results show that the proposed device has a < 0.5 dB insertion loss with < −17 dB crosstalk in C optical communication band. Fabrication tolerance analysis is also performed with respect to the deviations of MMI coupler width, PS width, slab height and upper-cladding refractive index, showing that this device could work well even when affected by considerable fabrication errors. With such a robust performance with a large bandwidth, this device offers potential applications for CMOS-compatible polarization diversity, especially in the booming 100 Gb/s coherent optical communications based on silicon photonics technology. PMID:25402029

  11. Quasi-two-dimensional Fermi gases at finite temperatures

    NASA Astrophysics Data System (ADS)

    Fischer, Andrea M.; Parish, Meera M.

    2014-12-01

    We consider a Fermi gas with short-range attractive interactions that is confined along one direction by a tight harmonic potential. For this quasi-two-dimensional (quasi-2D) Fermi gas, we compute the pressure equation of state, radiofrequency spectrum, and the superfluid critical temperature Tc using a mean-field theory that accounts for all the energy levels of the harmonic confinement. Our calculation for Tc provides a natural generalization of the Thouless criterion to the quasi-2D geometry, and it correctly reduces to the 3D expression derived from the local density approximation in the limit where the confinement frequency ωz→0 . Furthermore, our results suggest that Tc can be enhanced by relaxing the confinement and perturbing away from the 2D limit.

  12. Anomalous Faraday rotation in the ISM/ICM

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2016-10-01

    Faraday effect is a common and useful way to deduce cosmic magnetic fields in the interstellar and intracluster media (ISM and ICM). Faraday rotation is the result of magnetically-induced birefringence in a dielectric medium causing a linearly polarized wave to suffer a rotation of its polarization axis as it traverses such a medium. However, the standard λ2-law of the rotation angle may not hold in strongly turbulent plasmas. Electromagnetic high-frequency and/or small-scale fluctuations may lead to effective collisionality with the pitch-angle diffusion coefficient being an effective ``quasi-collision'' frequency. Recently, we showed that quasi-collisionality may radically alter radiative transport properties of plasmas, such as absorption, transmission and reflection and other effects, which can be very important in laboratory and astrophysical plasmas. Here we briefly discuss the quasi-collisional generalization of the classical Faraday effect, which is drastically modified and can even become negative. Furthermore, we explore the origin of the long-known anomaly of Faraday rotation in a famous Cygnus regions. We argue that the anomaly can be due to the anomalous Faraday rotation in a thin ``blanket'' of turbulent plasma at the front of an interstellar bubble/shock. Supported by KU CLAS and DOE Grant ID0000225143 (07/01/16).

  13. Conservative treatment of rotator cuff injuries.

    PubMed

    Bytomski, Jeffrey R; Black, Douglass

    2006-01-01

    Across all ages and activity levels, rotator cuff injuries are one of the most common causes of shoulder pain. The anatomy and biomechanics of the shoulder guide the history and physical exam toward the appropriate treatment of rotator cuff injuries. Rotator cuff tears are rare under the age of 40 unless accompanied by acute trauma. Throwing athletes are prone to rotator cuff injury from various causes of impingement (subacromial, internal, or secondary) and flexibility deficits, strength deficits, or both along the kinetic chain. Most rotator cuff injuries may be treated conservatively by using regimens of nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, and functional rehabilitation therapy. Injury prevention programs are essential for the long-term care of patients with rotator cuff disease, for primary prevention, and for prevention of recurrent injuries, unless a traumatically torn rotator cuff is present. Surgical management is reserved for refractory cases that have exhausted conservative measures.

  14. Quasi-Optical Transmission Line for 94-GHz Radar

    NASA Technical Reports Server (NTRS)

    Perez, Raul M.; Veruttipong, Watt

    2008-01-01

    A quasi-optical transmission line (QOTL) has been developed as a low-loss transmission line for a spaceborne cloudobserving radar instrument that operates at a nominal frequency of 94 GHz. This QOTL could also readily be redesigned for use in terrestrial millimeter-wave radar systems and millimeter-wave imaging systems. In the absence of this or another lowloss transmission line, it would be necessary to use a waveguide transmission line in the original radar application. Unfortunately, transmission losses increase and power-handling capacities of waveguides generally decrease with frequency, such that at 94 GHz, the limitation on transmitting power and the combined transmission and reception losses (greater than 5 dB) in a waveguide transmission line previously considered for the original application would be unacceptable. The QOTL functions as a very-lowloss, three-port circulator. The QOTL includes a shaped input mirror that can be rotated to accept 94-GHz transmitter power from either of two high-power amplifiers. Inside the QOTL, the transmitter power takes the form of a linearly polarized beam radiated from a feed horn. This beam propagates through a system of mirrors, each of which refocuses the beam to minimize diffraction losses. A magnetically biased ferrite disc is placed at one of the foci to utilize the Faraday effect to rotate the polarization of the beam by 45 degrees. The beam is then transmitted via an antenna system. The radar return (scatter from clouds, and/or reflections from other objects) is collected by the same antenna and propagates through the Faraday rotator in the reverse of the direction of propagation of the transmitted beam. In the Faraday rotator, the polarization of the received signal is rotated a further 45 degrees, so that upon emerging from the Faraday rotator, the received beam is polarized at 90 with respect to the transmitted beam. The transmitted and received signals are then separated by a wire-grid polarizer.

  15. Rapidly rotating polytropes in general relativity

    NASA Technical Reports Server (NTRS)

    Cook, Gregory B.; Shapiro, Stuart L.; Teukolsky, Saul A.

    1994-01-01

    We construct an extensive set of equilibrium sequences of rotating polytropes in general relativity. We determine a number of important physical parameters of such stars, including maximum mass and maximum spin rate. The stability of the configurations against quasi-radial perturbations is diagnosed. Two classes of evolutionary sequences of fixed rest mass and entropy are explored: normal sequences which behave very much like Newtonian evolutionary sequences, and supramassive sequences which exist solely because of relativistic effects. Dissipation leading to loss of angular momentum causes a star to evolve in a quasi-stationary fashion along an evolutionary sequence. Supramassive sequences evolve towards eventual catastrophic collapse to a black hole. Prior to collapse, the star must spin up as it loses angular momentum, an effect which may provide an observational precursor to gravitational collapse to a black hole.

  16. Radiation characteristics of quasi-periodic radio bursts in the Jovian high-latitude region

    NASA Astrophysics Data System (ADS)

    Kimura, Tomoki; Tsuchiya, Fuminori; Misawa, Hiroaki; Morioka, Akira; Nozawa, Hiromasa

    2008-12-01

    Ulysses had a "distant encounter" with Jupiter in February 2004. The spacecraft passed from north to south, and it observed Jovian radio waves from high to low latitudes (from +80° to +10°) for few months during its encounter. In this study, we present a statistical investigation of the occurrence characteristics of Jovian quasi-periodic bursts, using spectral data from the unified radio and plasma wave experiment (URAP) onboard Ulysses. The latitudinal distribution of quasi-periodic bursts is derived for the first time. The analysis suggested that the bursts can be roughly categorized into two types: one having periods shorter than 30 min and one with periods longer than 30 min, which is consistent with the results of the previous analysis of data from Ulysses' first Jovian flyby [MacDowall, R.J., Kaiser, M.L., Desch, M.D., Farrell, W.M., Hess, R.A., Stone, R.G., 1993. Quasi-periodic Jovian radio bursts: observations from the Ulysses radio and plasma wave. Experiment. Planet. Space Sci. 41, 1059-1072]. It is also suggested that the groups of quasi-periodic bursts showed a dependence on the Jovian longitude of the sub-solar point, which means that these burst groups are triggered during a particular rotational phase of the planet. Maps of the occurrence probability of these quasi-periodic bursts also showed a unique CML/MLAT dependence. We performed a 3D ray tracing analysis of the quasi-periodic burst emission to learn more about the source distribution. The results suggest that the longitudinal distribution of the occurrence probability depends on the rotational phase. The source region of quasi-periodic bursts seems to be located at an altitude between 0.4 and 1.4 Rj above the polar cap region ( L>30).

  17. Mode-hopping-free scanning over 2 THz by means of quasi-synchronous tuning

    NASA Astrophysics Data System (ADS)

    Wang, Shaokai; Li, Ye; Zhao, Yang; Wang, Qiang; Lin, Yige; Lin, Baike; Meng, Fei; Cao, Shiying; Cao, Jianping; Fang, Zhanjun; Zang, Erjun

    2014-03-01

    We report mode-hopping-free tuning (MHF) over 2 THz (6 nm) of a Littman-Metcalf-type external-cavity diode laser by means of quasi-synchronous tuning, wherein the pivot point is displaced 65 mm away from the conventional rigorous synchronous rotation center. An experimental method for judging the relative position between actual pivot location and the quasi-synchronous tuning line is developed. An adjustment structure with only one freedom of movement is enough to accurately locate the pivot point, and the precise requirement is relaxed to more than 300 μm for achieving a MHF tuning range of over 1THz in our configuration.

  18. Hollow cathode, quasi-steady MPD arc

    NASA Technical Reports Server (NTRS)

    Parmentier, N.; Jahn, R. G.

    1971-01-01

    A quasi-steady MPD accelerator has been operated with four different hollow cathodes over a power range from 5 kilowatts to 5 megawatts. The absolute level of the argon mass flow, as well as the fractional division of the flow between the cathode and the six standard chamber injectors, is varied over a range of 1 to 12 grams per second. For a fixed total current, it is observed that the voltage increases monotonically with mass flow rate, compared to the usual experience with solid cathodes where the voltage decreases with mass flow rate. For a fixed percentage of flow through the cathode, each hollow cathode configuration displays a minimum impedance at a particular value of the total mass flow. It is asserted that in order to keep the discharge inside the hollow cathode the magnetic pressure and gasdynamic pressure have to match inside the cavity.

  19. Development of quasi-isodynamic stellarators

    NASA Astrophysics Data System (ADS)

    Nührenberg, Jürgen

    2010-12-01

    Theoretical stellarator research from MHD-stable stellarators via quasi-helically symmetric ones to Wendelstein 7-X, quasi-axisymmetric tokamaks and quasi-isodynamic stellarators is sketched. Research strategy, computational aspects and various favorable properties are emphasized. The results found, but only together with the completion of according experimental devices and their scientific exploitation, may form a basis for selecting the confinement geometry most viable for fusion.

  20. Topological Structures in Rotating Stratified Flows

    NASA Astrophysics Data System (ADS)

    Redondo, J. M.; Carrillo, A.; Perez, E.

    2003-04-01

    Detailled 2D Particle traking and PIV visualizations performed on a series of large scale laboratory experiments at the Coriolis Platform of the SINTEF in Trondheim have revealed several resonances which scale on the Strouhal, the Rossby and the Richardson numbers. More than 100 experiments spanned a wide range of Rossby Deformation Radii and the topological structures (Parabolic /Eliptic /Hyperbolic) of the quasi-balanced stratified-rotating flows were studied when stirring (akin to coastal mixing) occured at a side of the tank. The strong asymetry favored by the total vorticity produces a wealth of mixing patterns.

  1. Rotational-vibrational Description of Nucleon Scattering on Actinide Nuclei Using a Dispersive Coupled-channel Optical Model

    NASA Astrophysics Data System (ADS)

    Quesada, J. M.; Capote, R.; Soukhovitskiı˜, E. Sh.; Chiba, S.

    2014-04-01

    Tamura's coupling formalism has been extended to consider low-lying rotational bands built on vibrational (single-particle) band heads in well-deformed even-even (odd) actinides. These additional excitations are introduced as a perturbation to the underlying rigid rotor structure that is known to describe well the ground state rotational band of major actinides. Coupling matrix elements needed in extended Tamura's formalism are derived for both even-even and odd actinides. Employed dispersive optical model (DCCOMP) replaces the incident proton energy Ep (for proton induced reactions) by the equivalent Coulomb subtracted energy in all potential terms including both the imaginary and real potentials with the corresponding dispersive corrections. Therefore, the optical potential becomes fully symmetric for protons and neutrons. This potential is used to fit simultaneously all the available optical experimental databases (including neutron strength functions) for nucleon scattering on 238U and 232Th (even even) nuclei. Quasi-elastic (p,n) scattering data to the isobaric analogue states of the target nuclei are also used to constrain the isovector part of the optical potential. Derived Lane-consistent DCCOMP is based on coupling of almost all levels below 1 MeV of excitation energy. The ground state, octupole, beta, gamma and non-axial rotational bands are considered for even nuclei, and rotational bands built on single-particle levels - for odd nuclei. Application of derived potential to odd targets based on a new coupling scheme is foreseen.

  2. Hydrogen rotation-vibration oscillator

    DOEpatents

    Rhodes, C.K.

    1974-01-29

    A laser system is described wherein molecular species of hydrogen and hydrogen isotopes are induced to oscillate on rotational-vibrational levels by subjecting the hydrogen to a transverse beam of electrons of a narrowly defined energy between about 1 and 5 eV, thereby producing high intensity and high energy output. (Official Gazette)

  3. Shear rotation numbers

    NASA Astrophysics Data System (ADS)

    Doeff, E.; Misiurewicz, M.

    1997-11-01

    This paper presents results on rotation numbers for orientation-preserving torus homeomorphisms homotopic to a Dehn twist. Rotation numbers and the rotation set for such homeomorphisms have been defined and initially investigated by the first author in a previous paper. Here we prove that each rotation number 0951-7715/10/6/017/img5 in the interior of the rotation set is realized by some compact invariant set, and that there is an ergodic measure on that set with mean rotation number 0951-7715/10/6/017/img5. It is also proved that the function which assigns its rotation set to such a homeomorphism is continuous. Finally, a counterexample is presented that shows that rational extremal points of the shear rotation set do not necessarily correspond to any periodic orbits.

  4. Power Harvesting from Rotation?

    ERIC Educational Resources Information Center

    Chicone, Carmen; Feng, Z. C.

    2008-01-01

    We show the impossibility of harvesting power from rotational motions by devices attached to the rotating object. The presentation is suitable for students who have studied Lagrangian mechanics. (Contains 2 figures.)

  5. Rotator cuff exercises

    MedlinePlus

    ... to these tendons may result in: Rotator cuff tendinitis, which is irritation and swelling of these tendons ... Brien MJ, Leggin BG, Williams GR. Rotator cuff tendinopathies and tears: surgery and therapy. In: Skirven TM, ...

  6. A simple quasi-diabatization scheme suitable for spectroscopic problems based on one-electron properties of interacting states

    SciTech Connect

    Cave, Robert J.; Stanton, John F.

    2016-02-07

    We present a simple quasi-diabatization scheme applicable to spectroscopic studies that can be applied using any wavefunction for which one-electron properties and transition properties can be calculated. The method is based on rotation of a pair (or set) of adiabatic states to minimize the difference between the given transition property at a reference geometry of high symmetry (where the quasi-diabatic states and adiabatic states coincide) and points of lower symmetry where quasi-diabatic quantities are desired. Compared to other quasi-diabatization techniques, the method requires no special coding, facilitates direct comparison between quasi-diabatic quantities calculated using different types of wavefunctions, and is free of any selection of configurations in the definition of the quasi-diabatic states. On the other hand, the method appears to be sensitive to multi-state issues, unlike recent methods we have developed that use a configurational definition of quasi-diabatic states. Results are presented and compared with two other recently developed quasi-diabatization techniques.

  7. Shaft-Rotation Detector

    NASA Technical Reports Server (NTRS)

    Randall, Richard L.

    1990-01-01

    Signal-processing subsystem generates signal indicative of rotation of shaft from output of accelerometer mounted on housing of bearing supporting shaft. Output of subsystem binary signal at frequency of rotation of shaft. Part of assembly of electronic equipment measuring vibrations in rotating machinery. Accelerometer mounted in such way sensitive to vibrations of shaft perpendicular to axis. Output of accelerometer includes noise and components of vibration at frequencies higher than rotational frequency of shaft.

  8. Rotations with Rodrigues' Vector

    ERIC Educational Resources Information Center

    Pina, E.

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…

  9. Robust rotational-velocity-Verlet integration methods

    NASA Astrophysics Data System (ADS)

    Rozmanov, Dmitri; Kusalik, Peter G.

    2010-05-01

    Two rotational integration algorithms for rigid-body dynamics are proposed in velocity-Verlet formulation. The first method uses quaternion dynamics and was derived from the original rotational leap-frog method by Svanberg [Mol. Phys. 92, 1085 (1997)]; it produces time consistent positions and momenta. The second method is also formulated in terms of quaternions but it is not quaternion specific and can be easily adapted for any other orientational representation. Both the methods are tested extensively and compared to existing rotational integrators. The proposed integrators demonstrated performance at least at the level of previously reported rotational algorithms. The choice of simulation parameters is also discussed.

  10. Trirotron: triode rotating beam radio frequency amplifier

    DOEpatents

    Lebacqz, Jean V.

    1980-01-01

    High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.

  11. A quasi-dense matching approach and its calibration application with Internet photos.

    PubMed

    Wan, Yanli; Miao, Zhenjiang; Wu, Q M Jonathan; Wang, Xifu; Tang, Zhen; Wang, Zhifei

    2015-03-01

    This paper proposes a quasi-dense matching approach to the automatic acquisition of camera parameters, which is required for recovering 3-D information from 2-D images. An affine transformation-based optimization model and a new matching cost function are used to acquire quasi-dense correspondences with high accuracy in each pair of views. These correspondences can be effectively detected and tracked at the sub-pixel level in multiviews with our neighboring view selection strategy. A two-layer iteration algorithm is proposed to optimize 3-D quasi-dense points and camera parameters. In the inner layer, different optimization strategies based on local photometric consistency and a global objective function are employed to optimize the 3-D quasi-dense points and camera parameters, respectively. In the outer layer, quasi-dense correspondences are resampled to guide a new estimation and optimization process of the camera parameters. We demonstrate the effectiveness of our algorithm with several experiments.

  12. Galaxy cluster's rotation

    NASA Astrophysics Data System (ADS)

    Manolopoulou, M.; Plionis, M.

    2017-03-01

    We study the possible rotation of cluster galaxies, developing, testing, and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude, and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z ≲ 0.1 with member galaxies selected from the Sloan Digital Sky Survey DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte Carlo simulation analysis, we find that ∼23 per cent of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ∼28 per cent. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation within 1.5 h^{-1}_{70} Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.

  13. Quasi-optical active antennas

    NASA Astrophysics Data System (ADS)

    Moussessian, Alina

    Quasi-optical power combiners such as quasi-optical grids provide an efficient means of combining the output power of many solid-state devices in free space. Unlike traditional power combiners no transmission lines are used, therefore, high output powers with less loss can be achieved at higher frequencies. This thesis investigates four different active antenna grids. The first investigation is into X-band High Electron Mobility Transistor (HEMT) grid amplifiers. Modelling and stability issues of these grids are discussed, and gain and power measurements are presented. A grid amplifier with a maximum efficiency of 22.5% at 10 GHz and a peak gain of 11dB is presented. The second grid is a varactor grid used as a positive feedback network for a grid amplifier to construct a tunable grid oscillator. Reflection measurements for the varactor grid show a tuning range of 1.2 GHz. The third grid is a self- complementary grid amplifier. The goal is to design a new amplifier with a unit cell structure that can be directly modelled using CAD tools. The properties of self- complementary structures are studied and used in the design of this new amplifier grid. The fourth grid is a 12 x 12 terahertz Schottky grid frequency doubler with a measured output power of 24 mW at 1 THz for 3.1-μs 500-GHz input pulses with a peak power of 47 W. A passive millimeter-wave travelling-wave antenna built on a dielectric substrate is also presented. Calculations indicate that the antenna has a gain of 15 dB with 3-dB beamwidths of 10o in the H-plane and 64o in the E-plane. Pattern measurements at 90 GHz support the theory. The antenna is expected to have an impedance in the range of 50/Omega to 80/Omega.

  14. Physics of untied rotating space elevators

    NASA Astrophysics Data System (ADS)

    Knudsen, Steven; Golubović, Leonardo

    2015-12-01

    We explore fundamental aspects of the physics of a novel class of dynamical systems, Rotating Space Elevators (RSE) (L. Golubović, S. Knudsen, Europhys. Lett. 86, 34001 (2009) and S. Knudsen, L. Golubović, Eur. Phys. J. Plus 129, 242 (2014)). An RSE is a loopy string reaching deep into outer space. The floppy RSE loop executes a double rotating motion due to which the objects sliding along the RSE string (climbers) can be transported far away from the Earth's surface without using internal engines or propulsion. By extensive numerical simulations and analytic calculations, this study addresses an interesting and provocative question at the very heart of the RSE physics: What will happen if one unties the rotating space elevator from the Earth? We find that the untied RSE exhibits rich nonlinear dynamics. In particular, strikingly, we find that the untied RSE may still behave as if it were tied to the planet. Such a quasi-tied yet untied RSE remains close to the Earth and exhibits persistent shape and enduring double rotating motion. Moreover, the climbers sliding along such a quasi-tied RSE move in much the same way as they do along a tied RSE. Under some conditions however we find that the untied RSE may undergo an instability leading it to a dynamical state in which the RSE hops well above the Earth surface. By changing the untied RSE parameters, the maximum height reached during hopping may be made to diverge. Such an untied RSE unbinds from the Earth to infinity, i.e., to interplanetary space.

  15. SEAL FOR ROTATING SHAFT

    DOEpatents

    Coffman, R.T.

    1957-12-10

    A seal is described for a rotatable shaft that must highly effective when the shaft is not rotating but may be less effective while the shaft is rotating. Weights distributed about a sealing disk secured to the shaft press the sealing disk against a tubular section into which the shiilt extends, and whem the shaft rotates, the centrifugal forces on the weights relieve the pressurc of the sealing disk against the tubular section. This action has the very desirible result of minimizing the wear of the rotating disk due to contact with the tubular section, while affording maximum sealing action when it is needed.

  16. Visualizing molecular unidirectional rotation

    NASA Astrophysics Data System (ADS)

    Lin, Kang; Song, Qiying; Gong, Xiaochun; Ji, Qinying; Pan, Haifeng; Ding, Jingxin; Zeng, Heping; Wu, Jian

    2015-07-01

    We directly visualize the spatiotemporal evolution of a unidirectional rotating molecular rotational wave packet. Excited by two time-delayed polarization-skewed ultrashort laser pulses, the cigar- or disk-shaped rotational wave packet is impulsively kicked to unidirectionally rotate as a quantum rotor which afterwards disperses and exhibits field-free revivals. The rich dynamics can be coherently controlled by varying the timing or polarization of the excitation laser pulses. The numerical simulations very well reproduce the experimental observations and intuitively revivify the thoroughgoing evolution of the molecular rotational wave packet of unidirectional spin.

  17. Predictors of human rotation.

    PubMed

    Stochl, Jan; Croudace, Tim

    2013-01-01

    Why some humans prefer to rotate clockwise rather than anticlockwise is not well understood. This study aims to identify the predictors of the preferred rotation direction in humans. The variables hypothesised to influence rotation preference include handedness, footedness, sex, brain hemisphere lateralisation, and the Coriolis effect (which results from geospatial location on the Earth). An online questionnaire allowed us to analyse data from 1526 respondents in 97 countries. Factor analysis showed that the direction of rotation should be studied separately for local and global movements. Handedness, footedness, and the item hypothesised to measure brain hemisphere lateralisation are predictors of rotation direction for both global and local movements. Sex is a predictor of the direction of global rotation movements but not local ones, and both sexes tend to rotate clockwise. Geospatial location does not predict the preferred direction of rotation. Our study confirms previous findings concerning the influence of handedness, footedness, and sex on human rotation; our study also provides new insight into the underlying structure of human rotation movements and excludes the Coriolis effect as a predictor of rotation.

  18. Minimax discrimination of quasi-Bell states

    SciTech Connect

    Kato, Kentaro

    2014-12-04

    An optimal quantum measurement is considered for the so-called quasi-Bell states under the quantum minimax criterion. It is shown that the minimax-optimal POVM for the quasi-Bell states is given by its square-root measurement and is applicable to the teleportation of a superposition of two coherent states.

  19. Quasi-Experimental Designs for Causal Inference

    ERIC Educational Resources Information Center

    Kim, Yongnam; Steiner, Peter

    2016-01-01

    When randomized experiments are infeasible, quasi-experimental designs can be exploited to evaluate causal treatment effects. The strongest quasi-experimental designs for causal inference are regression discontinuity designs, instrumental variable designs, matching and propensity score designs, and comparative interrupted time series designs. This…

  20. Quasi-Einstein metrics on hypersurface families

    NASA Astrophysics Data System (ADS)

    Hall, Stuart James

    2013-02-01

    We construct quasi-Einstein metrics on some hypersurface families. The hypersurfaces are circle bundles over the product of Fano, Kähler-Einstein manifolds. The quasi-Einstein metrics are related to various gradient Kähler-Ricci solitons constructed by Dancer and Wang and some Hermitian, non-Kähler, Einstein metrics constructed by Wang and Wang on the same manifolds.

  1. Quasi parton distributions and the gradient flow

    DOE PAGES

    Monahan, Christopher; Orginos, Kostas

    2017-03-22

    We propose a new approach to determining quasi parton distribution functions (PDFs) from lattice quantum chromodynamics. By incorporating the gradient flow, this method guarantees that the lattice quasi PDFs are finite in the continuum limit and evades the thorny, and as yet unresolved, issue of the renormalization of quasi PDFs on the lattice. In the limit that the flow time is much smaller than the length scale set by the nucleon momentum, the moments of the smeared quasi PDF are proportional to those of the lightfront PDF. Finally, we use this relation to derive evolution equations for the matching kernelmore » that relates the smeared quasi PDF and the light-front PDF.« less

  2. Cylindrical rotating triboelectric nanogenerator.

    PubMed

    Bai, Peng; Zhu, Guang; Liu, Ying; Chen, Jun; Jing, Qingshen; Yang, Weiqing; Ma, Jusheng; Zhang, Gong; Wang, Zhong Lin

    2013-07-23

    We demonstrate a cylindrical rotating triboelectric nanogenerator (TENG) based on sliding electrification for harvesting mechanical energy from rotational motion. The rotating TENG is based on a core-shell structure that is made of distinctly different triboelectric materials with alternative strip structures on the surface. The charge transfer is strengthened with the formation of polymer nanoparticles on surfaces. During coaxial rotation, a contact-induced electrification and the relative sliding between the contact surfaces of the core and the shell result in an "in-plane" lateral polarization, which drives the flow of electrons in the external load. A power density of 36.9 W/m(2) (short-circuit current of 90 μA and open-circuit voltage of 410 V) has been achieved by a rotating TENG with 8 strip units at a linear rotational velocity of 1.33 m/s (a rotation rate of 1000 r/min). The output can be further enhanced by integrating more strip units and/or applying larger linear rotational velocity. This rotating TENG can be used as a direct power source to drive small electronics, such as LED bulbs. This study proves the possibility to harvest mechanical energy by TENGs from rotational motion, demonstrating its potential for harvesting the flow energy of air or water for applications such as self-powered environmental sensors and wildlife tracking devices.

  3. Three-Dimensional Modeling of Quasi-Homologous Solar Jets

    NASA Technical Reports Server (NTRS)

    Pariat, E.; Antiochos, S. K.; DeVore, C. R.

    2010-01-01

    Recent solar observations (e.g., obtained with Hinode and STEREO) have revealed that coronal jets are a more frequent phenomenon than previously believed. This higher frequency results, in part, from the fact that jets exhibit a homologous behavior: successive jets recur at the same location with similar morphological features. We present the results of three-dimensional (31)) numerical simulations of our model for coronal jets. This study demonstrates the ability of the model to generate recurrent 3D untwisting quasi-homologous jets when a stress is constantly applied at the photospheric boundary. The homology results from the property of the 3D null-point system to relax to a state topologically similar to its initial configuration. In addition, we find two distinct regimes of reconnection in the simulations: an impulsive 3D mode involving a helical rotating current sheet that generates the jet, and a quasi-steady mode that occurs in a 2D-like current sheet located along the fan between the sheared spines. We argue that these different regimes can explain the observed link between jets and plumes.

  4. Rotating cooloing flows

    NASA Technical Reports Server (NTRS)

    Kley, Wilhelm; Mathews, William G.

    1995-01-01

    We describe the evolution of the hot interstellar medium in a large, slowly rotating elliptical galaxy. Although the rotation assumed is a small fraction of the circular velocity, in accordance with recent observations, it is sufficient to have a profound influence on the X-ray emission and cooling geometry of the interstellar gas. The hot gas cools into a disk that extends out to approximately 10 kpc. The cool, dusty disks observed in the majority of elliptical galaxies may arise naturally from internal cooling rather than from mergers with gas-rich companions. As a result of angular momentum conservation in the cooling flow, the soft X-ray isophotes are quite noticeably flatter than those of the stellar image. The gas temperature is higer along the rotation axis. The rotational velocity of the gas several kiloparcsecs above the central disk far exceeds the local stellar rotation and approaches the local circular velocity as it flows toward the galactic core. The detailed appearance of the X-ray image and velocity field of the X-ray gas provide information about the global rotational properties of giant ellipticals at radii too distant for optical observations. The overall pattern of rotation in these galaxies retains information about the origin of ellipticals, particularly of their merging history. In ellipticals having radio jets, if the jets are aligned with the rotation axis of the inner cooling flow, rotation within the jet could be sustained by the rotating environment. Since most large ellipticals have modest rotation, the X-ray observations at low spatial resolution, when interpreted with spherical theoretical models, give the impression that hot gas undergoes localized cooling to very low temperatures many kiloparcsecs from the galactic core. We suggest that such apparent cooling can result in a natural way as gas cools onto a rotating disk.

  5. Research on the characteristics of quasi-steady cavitation in a centrifugal pump

    NASA Astrophysics Data System (ADS)

    Lu, J. X.; Yuan, S. Q.; Li, X. J.; Si, Q. R.; Luo, Y.

    2015-01-01

    With the pressure decreasing, the process of cavitation in a centrifugal pump could be summarized as incipient cavitation, quasi-steady cavitation and unsteady cavitation. Quasi-steady cavitation is the condition that is between the incipient cavitation and unsteady cavitation in a centrifugal pump. Under this condition, the intensity of cavitation is relatively weak, and the head of the pump almost remains unchanged, but the cavitation exists, causing damage to the impeller by pitting and erosion. So it is important to investigate the quasi-steady cavitation. In this paper, both the numerical and experimental methods had been carried out to investigate the characteristics of quasi-steady cavitation. The internal flow in the pump, the performance of cavitation and the inlet and outlet pressure pulsation of the pump measured through experimental method have been studied under different NPSHa conditions. It was found that the head decreases about 0.77%-1.38% from non-cavitation condition and it could be regarded as the quasi-steady cavitation. Little change has been found from the internal flow between non-cavitation condition and quasi-steady cavitation condition. The period of inlet pressure pulsation changes from the time that the blade passes by to the period of shaft rotating with the development of cavitation. The dominant frequency of the inlet pressure pulsation is two times of shaft frequency whose amplitudes decrease firstly and then increase to a peak value, followed by a decrease to a low value in quasi-steady cavitation conditions. The dominant frequency of the outlet pressure pulsation is blade passing frequency whose amplitudes increase firstly and then decrease gradually with the decrease of NPSHa.

  6. Quasi-Periodically Driven Quantum Systems

    NASA Astrophysics Data System (ADS)

    Verdeny, Albert; Puig, Joaquim; Mintert, Florian

    2016-10-01

    Floquet theory provides rigorous foundations for the theory of periodically driven quantum systems. In the case of non-periodic driving, however, the situation is not so well understood. Here, we provide a critical review of the theoretical framework developed for quasi-periodically driven quantum systems. Although the theoretical footing is still under development, we argue that quasi-periodically driven quantum systems can be treated with generalisations of Floquet theory in suitable parameter regimes. Moreover, we provide a generalisation of the Floquet-Magnus expansion and argue that quasi-periodic driving offers a promising route for quantum simulations.

  7. Quasi-static self-powered sensing and data logging

    NASA Astrophysics Data System (ADS)

    Lajnef, Nizar; Chakrabartty, Shantanu; Burgueño, Rigoberto; Borchani, Wassim

    2014-04-01

    Many signals of interest in the assessment of structural systems lie in the quasi-static range (frequency << 1Hz). This poses a significant challenge for the development of self-powered sensors that are required not only to monitor these events but also to harvest the energy for sensing, computation and storage from the signal being monitored. This paper combines the use of mechanically-equivalent frequency modulators and piezo-powered threshold detection modules capable of computation and data storage with a total current less than 10nA. The system is able to achieve events counting for input deformations at frequencies lower than 0.1Hz. The used mechanically-equivalent frequency modulators allow the transformation of the low-amplitude and low-rate quasi-static deformations into an amplified input to a piezoelectric transducer. The sudden transitions in unstable mode branch switching, during the elastic postbuckling response of slender columns and plates, are used to generate high-rate deformations. Experimental results show that an oscillating semi-crystalline plastic polyvinylidene fluoride (PVDF), attached to the up-converting modules, is able to generate a harvestable energy at levels between 0.8μJ to 2μJ. In this work, we show that a linear injection response of our combined frequency up-converter / piezo-floating-gate sensing system can be used for self-powered measurement and recording of quasi-static deformations levels. The experimental results demonstrate that a sensor fabricated in a 0.5- μm CMOS technology can count and record the number of quasi-static input events, while operating at a power level significantly lower than 1μW.

  8. Quantum and quasi-classical calculations for the S+ + H2(v, j) →SH+(v′, j′)+H reactive collisions

    PubMed Central

    Zanchet, Alexandre; Roncero, Octavio; Bulut, Niyazi

    2016-01-01

    State-to-state cross sections for the S+ + H2(v, j) → SH+ (v′, j′) + H endothermic reaction are obtained with quantum wave packet(WP) and quasi-classical (QCT) methods for different initial rovibrational H2(v, j) over a wide range of translation energies. Final state distribution as a function of the initial quantum number is obtained and discussed. Additionally, the effect of the internal excitation of H2 on the reactivity is carefully studied. It appears that energy transfer among modes is very inefficient, that vibrational energy is the most favorable for reaction and rotational excitation significantly enhance reactivity when vibrational energy is sufficient to reach the product. Special attention is also paid on an unusual discrepancy between classical and quantum dynamics for low rotational levels while agreement improves with rotational excitation of H2, An interesting resonant behaviour found in WP calculations is also discussed and is associated to the existence of roaming classical trajectories that enhance the reactivity of the title reaction. Finally, a comparison with the experimental results of Stowe et al.[1] for S+ + HD and S+ +D2 reactions, finding a reasonably good agreement with those results. PMID:27055725

  9. Principle of bio-inspired insect wing rotational hinge design

    NASA Astrophysics Data System (ADS)

    Fei, Fan

    A principle for designing and fabricating bio-inspired miniature artificial insect flapping wing using flexure rotational hinge design is presented. A systematic approach of selecting rotational hinge stiffness value is proposed. Based on the understanding of flapping wing aerodynamics, a dynamic simulation is constructed using the established quasi-steady model and the wing design. Simulations were performed to gain insight on how different parameters affect the wing rotational response. Based on system resonance a model to predict the optimal rotational hinge stiffness based on given wing parameter and flapping wing kinematic is proposed. By varying different wing parameters, the proposed method is shown to be applicable to a wide range of wing designs with different sizes and shapes. With the selected hinge stiffness value, aspects of the rotational joint design is discussed and an integrated wing-hinge structure design using laminated carbon fiber and polymer film is presented. Manufacturing process of such composite structure is developed to achieve high accuracy and repeatability. The yielded hinge stiffness is verified by measurements. To validate the proposed model, flapping wing experiments were conducted. A flapping actuation set up is built using DC motor and a controller is implemented on a microcontroller to track desired wing stroke kinematic. Wing stroke and rotation kinematic were extracted using a high speed camera and the lift generation is evaluated. A total of 49 flapping experiments were presented, experimental data shows good correlation with the model's prediction. With the wing rotational hinge stiffness designed so that the rotational resonant frequency is twice as the stroke frequency, the resulting wing rotation generates near optimal lift. With further simulation, the proposed model shows low sensitivity to wing parameter variation. As a result, giving a design parameter of a flapping wing robot platform, the proposed principle can

  10. Diamagnetism of rotating plasma

    SciTech Connect

    Young, W. C.; Hassam, A. B.; Romero-Talamas, C. A.; Ellis, R. F.; Teodorescu, C.

    2011-11-15

    Diamagnetism and magnetic measurements of a supersonically rotating plasma in a shaped magnetic field demonstrate confinement of plasma pressure along the magnetic field resulting from centrifugal force. The Grad-Shafranov equation of ideal magnetohydrodynamic force balance, including supersonic rotation, is solved to confirm that the predicted angular velocity is in agreement with spectroscopic measurements of the Doppler shifts.

  11. Wideband rotating junctions

    NASA Astrophysics Data System (ADS)

    Pochernyaev, V. N.

    1993-06-01

    Rotating junctions of coaxial-waveguide and waveguide type with a traveling wave coefficient exceeding 0.8 in a wide frequency range are considered. The design of these junctions is based on a method of the theory of electrodynamic circuits. Numerical results are obtained for rotating junctions of partially filled rectangular waveguide type and their particular cases.

  12. The Weighted Oblimin Rotation.

    ERIC Educational Resources Information Center

    Lorenzo-Seva, Urbano

    2000-01-01

    Demonstrates that the weighting procedure proposed by E. Cureton and S. Mulaik (1975) can be applied to the Direct Oblimin approach of D. Clarkson and R. Jennrich (1988) to provide good results. The rotation method obtained is called Weighted Oblimin. Compared this method to other rotation methods with favorable results. (SLD)

  13. SMAP Faraday Rotation

    NASA Technical Reports Server (NTRS)

    Le Vine, David

    2016-01-01

    Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

  14. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  15. Quasi-random array imaging collimator

    DOEpatents

    Fenimore, E.E.

    1980-08-20

    A hexagonally shaped quasi-random no-two-holes-touching imaging collimator. The quasi-random array imaging collimator eliminates contamination from small angle off-axis rays by using a no-two-holes-touching pattern which simultaneously provides for a self-supporting array increasing throughput by elimination of a substrate. The present invention also provides maximum throughput using hexagonally shaped holes in a hexagonal lattice pattern for diffraction limited applications. Mosaicking is also disclosed for reducing fabrication effort.

  16. Rotation sensor switch

    DOEpatents

    Sevec, John B.

    1978-01-01

    A protective device to provide a warning if a piece of rotating machinery slows or stops comprises a pair of hinged weights disposed to rotate on a rotating shaft of the equipment. When the equipment is rotating, the weights remain in a plane essentially perpendicular to the shaft and constitute part of an electrical circuit that is open. When the shaft slows or stops, the weights are attracted to a pair of concentric electrically conducting disks disposed in a plane perpendicular to the shaft and parallel to the plane of the weights when rotating. A disk magnet attracts the weights to the electrically conducting plates and maintains the electrical contact at the plates to complete an electrical circuit that can then provide an alarm signal.

  17. CENTRAL ROTATIONS OF MILKY WAY GLOBULAR CLUSTERS

    SciTech Connect

    Fabricius, Maximilian H.; Rukdee, Surangkhana; Saglia, Roberto P.; Bender, Ralf; Hopp, Ulrich; Thomas, Jens; Williams, Michael J.; Noyola, Eva; Opitsch, Michael

    2014-06-01

    Most Milky Way globular clusters (GCs) exhibit measurable flattening, even if on a very low level. Both cluster rotation and tidal fields are thought to cause this flattening. Nevertheless, rotation has only been confirmed in a handful of GCs, based mostly on individual radial velocities at large radii. We are conducting a survey of the central kinematics of Galactic GCs using the new Integral Field Unit instrument VIRUS-W. We detect rotation in all 11 GCs that we have observed so far, rendering it likely that a large majority of the Milky Way GCs rotate. We use published catalogs of GCs to derive central ellipticities and position angles. We show that in all cases where the central ellipticity permits an accurate measurement of the position angle, those angles are in excellent agreement with the kinematic position angles that we derive from the VIRUS-W velocity fields. We find an unexpected tight correlation between central rotation and outer ellipticity, indicating that rotation drives flattening for the objects in our sample. We also find a tight correlation between central rotation and published values for the central velocity dispersion, most likely due to rotation impacting the old dispersion measurements.

  18. Central Rotations of Milky Way Globular Clusters

    NASA Astrophysics Data System (ADS)

    Fabricius, Maximilian H.; Noyola, Eva; Rukdee, Surangkhana; Saglia, Roberto P.; Bender, Ralf; Hopp, Ulrich; Thomas, Jens; Opitsch, Michael; Williams, Michael J.

    2014-06-01

    Most Milky Way globular clusters (GCs) exhibit measurable flattening, even if on a very low level. Both cluster rotation and tidal fields are thought to cause this flattening. Nevertheless, rotation has only been confirmed in a handful of GCs, based mostly on individual radial velocities at large radii. We are conducting a survey of the central kinematics of Galactic GCs using the new Integral Field Unit instrument VIRUS-W. We detect rotation in all 11 GCs that we have observed so far, rendering it likely that a large majority of the Milky Way GCs rotate. We use published catalogs of GCs to derive central ellipticities and position angles. We show that in all cases where the central ellipticity permits an accurate measurement of the position angle, those angles are in excellent agreement with the kinematic position angles that we derive from the VIRUS-W velocity fields. We find an unexpected tight correlation between central rotation and outer ellipticity, indicating that rotation drives flattening for the objects in our sample. We also find a tight correlation between central rotation and published values for the central velocity dispersion, most likely due to rotation impacting the old dispersion measurements. This Letter includes data taken at The McDonald Observatory of The University of Texas at Austin.

  19. Doubles of Quasi-Quantum Groups

    NASA Astrophysics Data System (ADS)

    Hausser, Frank; Nill, Florian

    In [Dr1] Drinfeld showed that any finite dimensional Hopf algebra extends to a quasitriangular Hopf algebra , the quantum double of . Based on the construction of a so-called diagonal crossed product developed by the authors in [HN], we generalize this result to the case of quasi-Hopf algebras . As for ordinary Hopf algebras, as a vector space the ``quasi-quantum double'' is isomorphic to , where denotes the dual of . We give explicit formulas for the product, the coproduct, the R-matrix and the antipode on and prove that they fulfill Drinfeld's axioms of a quasitriangular quasi-Hopf algebra. In particular becomes an associative algebra containing as a quasi-Hopf subalgebra. On the other hand, is not a subalgebra of unless the coproduct on is strictly coassociative. It is shown that the category of finite dimensional representations of coincides with what has been called the double category of -modules by S. Majid [M2]. Thus our construction gives a concrete realization of Majid's definition of quasi-quantum doubles in terms of a Tannaka-Krein-like reconstruction procedure. The whole construction is shown to generalize to weak quasi-Hopf algebras with now being linearly isomorphic to a subspace of $.

  20. The microwave spectrum of methyl isoselenocyanate: CH 3NCSe as a quasi-symmetric top

    NASA Astrophysics Data System (ADS)

    Koput, J.; Stroh, F.; Winnewisser, M.

    1990-03-01

    The microwave spectrum of methyl isoselenocyanate, CH 3NCSe, has been measured in the region 18-40 GHz. The a-type J + 1 ← J rotational transitions ( J = 5 to 10) in the ground vibrational state of the molecule have been assigned for the three isotopic species with 82Se, 80Se, and 78Se. For the most abundant isotopic species, with 80Se, the rotational transitions in the excited states of the CNC bending mode v10 = 1 and 2 have also been assigned. Contrary to the previous investigation [T. Sakaizumi et al., Bull. Chem. Soc. Japan59, 1614-1616 (1986)], it has been shown that the observed spectrum is consistent with that of a quasi-symmetric top molecule. The rotation-vibration constants have been determined, showing an unusual variation with excitation of the CNC bending mode. The CNC bending potential function has been determined in preliminary calculations using a quasi-symmetric top model. The potential function is calculated to be very anharmonic, with an equilibrium CNC angle of about 162° and a barrier to linearity of the CNCSe skeleton of about 25 cm -1. From accidental resonances observed for the ground state transitions the barrier to internal rotation of the methyl group was estimated to be about 3 cm -1.

  1. Rotatable crucible for rapid solidification process

    NASA Technical Reports Server (NTRS)

    Gaspar, Thomas (Inventor)

    1990-01-01

    This invention relates to an apparatus for producing filament, fiber, ribbon or film from a molten material, comprising a preferably heat extracting crucible which contains a pool of molten material at a selected horizontal level in the pool. The crucible has an opening extending from above the free surface level to a bottom edge of the opening, the bottom edge being sufficiently below the free surface level so that the molten material cannot form and hold a meniscus by surface tension between the edge and the level of the free surface and further comprises a heat extracting substrate laterally disposed with respect to the crucible and which rotates about an axis of rotation. The substrate is positioned adjacent the edge of the opening which confines the molten material and prevents it from overflowing downwardly out of the crucible. The invention features rotating means which includes a first drive means for tiltably rotating the crucible about an axis of rotation which is coaxial with the axis of rotation of the substrate, so the crucible edge can be maintained a predetermined constant distance from the substrate. The distance chosen is suitable for depositing molten material on the substrate and the apparatus also has a second drive means which is drivingly connected to the substrate for continuously moving the surface of the substrate upwardly past the edge and a melt front formed at the interface of the molten material and the substrate surface.

  2. On the co-orbital motion in the planar restricted three-body problem: the quasi-satellite motion revisited

    NASA Astrophysics Data System (ADS)

    Pousse, Alexandre; Robutel, Philippe; Vienne, Alain

    2017-02-01

    In the framework of the planar and circular restricted three-body problem, we consider an asteroid that orbits the Sun in quasi-satellite motion with a planet. A quasi-satellite trajectory is a heliocentric orbit in co-orbital resonance with the planet, characterized by a nonzero eccentricity and a resonant angle that librates around zero. Likewise, in the rotating frame with the planet, it describes the same trajectory as the one of a retrograde satellite even though the planet acts as a perturbator. In the last few years, the discoveries of asteroids in this type of motion made the term "quasi-satellite" more and more present in the literature. However, some authors rather use the term "retrograde satellite" when referring to this kind of motion in the studies of the restricted problem in the rotating frame. In this paper, we intend to clarify the terminology to use, in order to bridge the gap between the perturbative co-orbital point of view and the more general approach in the rotating frame. Through a numerical exploration of the co-orbital phase space, we describe the quasi-satellite domain and highlight that it is not reachable by low eccentricities by averaging process. We will show that the quasi-satellite domain is effectively included in the domain of the retrograde satellites and neatly defined in terms of frequencies. Eventually, we highlight a remarkable high eccentric quasi-satellite orbit corresponding to a frozen ellipse in the heliocentric frame. We extend this result to the eccentric case (planet on an eccentric motion) and show that two families of frozen ellipses originate from this remarkable orbit.

  3. Angular velocity distribution of a granular planar rotator in a thermalized bath.

    PubMed

    Piasecki, J; Talbot, J; Viot, P

    2007-05-01

    The kinetics of a granular planar rotator with a fixed center undergoing inelastic collisions with bath particles is analyzed both numerically and analytically by means of the Boltzmann equation. The angular velocity distribution evolves from quasi-Gaussian in the Brownian limit to an algebraic decay in the limit of an infinitely light particle. In addition, we compare this model to that of a planar rotator with a free center and discuss the prospects for experimental confirmation of these results.

  4. Quasi-Biennial Oscillation as the Result of Planetary Motion

    NASA Astrophysics Data System (ADS)

    Retejum, Alexey

    QUASI-BIENNIAL OSCILLATION AS THE RESULT OF PLANETARY MOTION A.Ju.Retejum Lomonosov Moscow State University, aretejum@yandex.ru A remarkable phenomenon of quasi-biennial oscillation (QBO) attracts a growing attention for its unclear origin and possible global impact. A comprehensive theory of this phenomenon should answer the following questions: 1. Why does the phase change of the atmospheric circulation on average occur every 800 days? 2. When does the cycle length decreases or increases? 3. Wherefore the regular wind shift is observed in the equatorial stratosphere only? 4. What could cause a sudden reverse in zonal wind direction? 5. Why the generating impulse travels from the border between the atmosphere and outer space downwards without significant loss of power? 6. What is the reason of known differences in behavior patterns between west and east winds? 7. How do middle and upper latitudes respond to the remote signal? Unfortunately all the explanation of QBO that have been given so far, unable to meet the above criteria. The author proposes an alternative idea of the external forcing due to motion of Mars, Jupiter and Venus. This study is based on the QBO Index data at the 30-hPa Height for the 1979-2013 period (http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index). Having in mind that the oscillation is symmetric about the Equator, where the Earth rotation speed is highest, one examined on the first stage relationships between the QBO manifestation and the length of day. A ten-year comparison of slow and fast spinning periods (1979-1983, 1991-1995 and 2000-2006, 2009-2011 respectively) reveals a significant difference in west and east winds strengths. The same picture can be observed if mean monthly data for March-April (the length of day maximum) and July (the length of day minimum) are collated. This is the answer to the question # 3. The exact answers to questions # 1 and # 2 give an analysis of the dependence of the wind reverse time on the moments

  5. Rotatable seal assembly. [Patent application; rotating targets

    DOEpatents

    Logan, C.M.; Garibaldi, J.L.

    1980-11-12

    An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an O-ring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers.

  6. Rotating reactor studies

    NASA Technical Reports Server (NTRS)

    Roberts, Glyn O.

    1991-01-01

    Undesired gravitational effects such as convection or sedimentation in a fluid can sometimes be avoided or decreased by the use of a closed chamber uniformly rotated about a horizontal axis. In a previous study, the spiral orbits of a heavy or buoyant particle in a uniformly rotating fluid were determined. The particles move in circles, and spiral in or out under the combined effects of the centrifugal force and centrifugal buoyancy. A optimization problem for the rotation rate of a cylindrical reactor rotated about its axis and containing distributed particles was formulated and solved. Related studies in several areas are addressed. A computer program based on the analysis was upgraded by correcting some minor errors, adding a sophisticated screen-and-printer graphics capability and other output options, and by improving the automation. The design, performance, and analysis of a series of experiments with monodisperse polystyrene latex microspheres in water were supported to test the theory and its limitations. The theory was amply confirmed at high rotation rates. However, at low rotation rates (1 rpm or less) the assumption of uniform solid-body rotation of the fluid became invalid, and there were increasingly strong secondary motions driven by variations in the mean fluid density due to variations in the particle concentration. In these tests the increase in the mean fluid density due to the particles was of order 0.015 percent. To a first approximation, these flows are driven by the buoyancy in a thin crescent-shaped depleted layer on the descending side of the rotating reactor. This buoyancy distribution is balanced by viscosity near the walls, and by the Coriolis force in the interior. A full analysis is beyond the scope of this study. Secondary flows are likely to be stronger for buoyant particles, which spiral in towards the neutral point near the rotation axis under the influence of their centrifugal buoyancy. This is because the depleted layer is

  7. Chaotic rotation of Hyperion?

    NASA Technical Reports Server (NTRS)

    Binzel, R. P.; Green, J. R.; Opal, C. B.

    1986-01-01

    Thomas et al. (1984) analyzed 14 Voyager 2 images of Saturn's satellite Hyperion and interpreted them to be consistent with a coherent (nonchaotic) rotation period of 13.1 days. This interpretation was criticized by Peale and Wisdom (1984), who argued that the low sampling frequency of Voyager data does not allow chaotic or nonchaotic rotation to be distinguished. New observations obtained with a higher sampling frequency are reported here which conclusively show that the 13.1 day period found by Thomas et al. was not due to coherent rotation.

  8. Quasi steady-state aerodynamic model development for race vehicle simulations

    NASA Astrophysics Data System (ADS)

    Mohrfeld-Halterman, J. A.; Uddin, M.

    2016-01-01

    Presented in this paper is a procedure to develop a high fidelity quasi steady-state aerodynamic model for use in race car vehicle dynamic simulations. Developed to fit quasi steady-state wind tunnel data, the aerodynamic model is regressed against three independent variables: front ground clearance, rear ride height, and yaw angle. An initial dual range model is presented and then further refined to reduce the model complexity while maintaining a high level of predictive accuracy. The model complexity reduction decreases the required amount of wind tunnel data thereby reducing wind tunnel testing time and cost. The quasi steady-state aerodynamic model for the pitch moment degree of freedom is systematically developed in this paper. This same procedure can be extended to the other five aerodynamic degrees of freedom to develop a complete six degree of freedom quasi steady-state aerodynamic model for any vehicle.

  9. Stability of Rigidly Rotating Supermassive Stars against Gravitational Collapse

    NASA Astrophysics Data System (ADS)

    Shibata, Masaru; Uchida, Haruki; Sekiguchi, Yu-ichiro

    2016-02-01

    We revisit secular stability against quasi-radial collapse for rigidly rotating supermassive stars (SMSs) in general relativity. We suppose that the SMSs are in a nuclear-burning phase and can be modeled by polytropic equations of state with the polytropic index np slightly smaller than 3. The stability is determined in terms of the turning point method. We find a fitting formula of the stability condition for the plausible range of np (2.95≲ {n}{{p}}≲ 3) for SMSs. This condition reconfirms that while non-rotating SMSs with a mass of ˜ {10}5{M}⊙ -{10}6{M}⊙ may undergo a general relativistically induced quasi-radial collapse, rigidly rotating SMSs with a ratio of rotational to gravitational potential energy (β) of ˜ {10}-2 are likely to be stable against collapse unless they are able to accrete ˜5 times more mass during the (relatively brief) hydrogen-burning phase of their evolution. We discuss the implications of our results.

  10. Quasi-idempotent Rota-Baxter operators arising from quasi-idempotent elements

    NASA Astrophysics Data System (ADS)

    Jian, Run-Qiang

    2017-02-01

    In this short note, we construct quasi-idempotent Rota-Baxter operators by quasi-idempotent elements and show that every finite dimensional Hopf algebra admits nontrivial Rota-Baxter algebra structures and tridendriform algebra structures. Several concrete examples are provided, including finite quantum groups and Iwahori-Hecke algebras.

  11. KIC 10526294: a slowly rotating B star with rotationally split, quasi-equally spaced gravity modes (Corrigendum)

    NASA Astrophysics Data System (ADS)

    Pápics, P. I.; Moravveji, E.; Aerts, C.; Tkachenko, A.; Triana, S. A.; Bloemen, S.; Southworth, J.

    2014-10-01

    Based on observations made with the William Herschel Telescope operated by the Isaac Newton Group on the island of La Palma at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Appendices are available in electronic form at http://www.aanda.org

  12. Rotating mobile launcher

    NASA Technical Reports Server (NTRS)

    Gregory, T. J.

    1977-01-01

    Apparatus holds remotely piloted arm that accelerates until launching speed is reached. Then vehicle and counterweight at other end of arm are released simultaneously to avoid structural damage from unbalanced rotating forces.

  13. The Rotating Mirror.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1981-01-01

    Discusses theory of the rotating mirror, its use in measuring the velocity of the electrical signal in wires, and the velocity of light. Concludes with a description of the manometric flame apparatus developed for analyzing sound waves. (SK)

  14. Rotator Cuff Injuries

    MedlinePlus

    ... cuff are common. They include tendinitis, bursitis, and injuries such as tears. Rotator cuff tendons can become ... cuff depends on age, health, how severe the injury is, and how long you've had the ...

  15. Rotator cuff problems

    MedlinePlus

    Miller RH III, Azar FM, Throckmorton TW. Shoulder and elbow injuries. In: Canale ST, Beaty JH, eds. ... Krishnan SG. Rotator cuff and impingement lesions. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ...

  16. Rotator cuff repair - slideshow

    MedlinePlus

    ... presentations/100229.htm Rotator cuff repair - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  17. Quasi-kernel polynomials and convergence results for quasi-minimal residual iterations

    NASA Technical Reports Server (NTRS)

    Freund, Roland W.

    1992-01-01

    Recently, Freund and Nachtigal have proposed a novel polynominal-based iteration, the quasi-minimal residual algorithm (QMR), for solving general nonsingular non-Hermitian linear systems. Motivated by the QMR method, we have introduced the general concept of quasi-kernel polynomials, and we have shown that the QMR algorithm is based on a particular instance of quasi-kernel polynomials. In this paper, we continue our study of quasi-kernel polynomials. In particular, we derive bounds for the norms of quasi-kernel polynomials. These results are then applied to obtain convergence theorems both for the QMR method and for a transpose-free variant of QMR, the TFQMR algorithm.

  18. The Orbit and Future Motion of Earth Quasi-Satellite 2016 HO3

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-10-01

    The newly discovered small asteroid 2016 HO3 is not only co-orbital with the Earth, it is currently trapped as a quasi-satellite, and it will remain a constant companion of our planet for centuries to come. Although it orbits the Sun, not the Earth, in a frame rotating with the Earth the asteroid appears to make yearly loops around our planet, and also bobs up and down through the ecliptic due to its 8-degree orbital inclination. What makes this asteroid a quasi-satellite is the fact that the Earth's gravity influences its motion so that it never wanders farther away than about 100 lunar distances. In the rotating frame, the asteroid's yearly cycles librate back and forth along the Earth's orbit, with a period of about 45 years. One other asteroid, 2003 YN107, followed a similar librational pattern from 1997 to 2006, but has since departed our vicinity. 2016 HO3, on the other hand, will continue to librate about our planet for centuries to come, making it the best and most stable example of a quasi-satellite to date.

  19. Rotator cuff injuries.

    PubMed

    Crusher, R H

    2000-07-01

    Different types of rotator cuff injuries frequently present to Accident and Emergency departments and minor injury units but can be difficult to differentiate clinically. This brief case study describes the examination and diagnosis of related shoulder injuries, specifically rotator cuff tears/disruption and calcifying supraspinatus tendinitis. The relevant anatomy and current therapies for these injuries is also discussed to enable the emergency nurse practitioner to have a greater understanding of the theory surrounding their diagnosis and treatments.

  20. Rotational rate sensor

    DOEpatents

    Hunter, Steven L.

    2002-01-01

    A rate sensor for angular/rotational acceleration includes a housing defining a fluid cavity essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.

  1. Rotational spectrum of phenylglycinol

    NASA Astrophysics Data System (ADS)

    Simão, Alcides; Peña, Isabel; Cabezas, Carlos; Alonso, José L.

    2014-11-01

    Solid samples of phenylglycinol were vaporized by laser ablation and investigated through rotational spectroscopy in a supersonic expansion using two different techniques: chirped pulse Fourier transform microwave spectroscopy and narrow band molecular beam Fourier transform microwave spectroscopy. One conformer, bearing an O-H···N and an N-H···π intramolecular hydrogen bonds, could be successfully identified by comparison of the experimental rotational and 14N nuclear quadruple coupling constants with those predicted theoretically.

  2. Rotating arc spark plug

    DOEpatents

    Whealton, John H.; Tsai, Chin-Chi

    2003-05-27

    A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

  3. Instability in Rotating Machinery

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The proceedings contain 45 papers on a wide range of subjects including flow generated instabilities in fluid flow machines, cracked shaft detection, case histories of instability phenomena in compressors, turbines, and pumps, vibration control in turbomachinery (including antiswirl techniques), and the simulation and estimation of destabilizing forces in rotating machines. The symposium was held to serve as an update on the understanding and control of rotating machinery instability problems.

  4. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  5. Rotation during lifting tasks: effects of rotation frequency and task order on localized muscle fatigue and performance.

    PubMed

    Horton, Leanna M; Nussbaum, Maury A; Agnew, Michael J

    2015-01-01

    Though widely considered to reduce the risk of work-related musculoskeletal disorders, there is limited evidence suggesting that rotating between tasks is effective in doing so. The purpose of the current study was to quantify the effects of rotation and parameters of rotation (frequency and task order) on muscle fatigue and performance. This was done using a simulated lifting task, with rotation between two levels of loading of the same muscle groups. Twelve participants completed six experimental sessions during which repetitive box lifting was performed for one hour either with or without rotation. When rotation was present, it occurred every 15 minutes or every 30 minutes and was between two load levels (box weights). Rotation reduced fatigue and cardiovascular demand compared to the heavier load without rotation, with a mean reduction of ∼33% in perceived discomfort and a ∼17% reduction in percentage of heart rate reserve. Further, rotation increased fatigue and cardiovascular demand compared to the lighter load without rotation, with a mean increase of ∼34% perceived discomfort and a ∼19% increase in percentage of heart rate reserve. Neither rotation frequency nor task order had definitive effects, though maximum discomfort ratings were nearly 20% higher when starting with the lighter load task. These parameters of rotation should be further evaluated under more realistic task conditions.

  6. Ego-rotation and object-rotation in major depressive disorder.

    PubMed

    Chen, Jiu; Yang, Laiqi; Ma, Wentao; Wu, Xingqu; Zhang, Yan; Wei, Dunhong; Liu, Guangxiong; Deng, Zihe; Hua, Zhen; Jia, Ting

    2013-08-30

    Mental rotation (MR) performance provides a direct insight into a prototypical higher-level visuo-spatial cognitive operation. Previous studies suggest that progressive slowing with an increasing angle of orientation indicates a specific wing of object-based mental transformations in the psychomotor retardation that occurs in major depressive disorder (MDD). It is still not known, however, whether the ability of object-rotation is associated with the ability of ego-rotation in MDD. The present study was designed to investigate the level of impairment of mental transformation abilities in MDD. For this purpose we tested 33 MDD (aged 18-52 years, 16 women) and 30 healthy control subjects (15 women, age and education matched) by evaluating the performance of MDD subjects with regard to ego-rotation and object-rotation tasks. First, MDD subjects were significantly slower and made more errors than controls in mentally rotating hands and letters. Second, MDD and control subjects displayed the same pattern of response times to stimuli at various orientations in the letter task but not the hand task. Third, in particular, MDD subjects were significantly slower and made more errors during the mental transformation of hands than letters relative to control subjects and were significantly slower and made more errors in physiologically impossible angles than physiologically possible angles in the mental rotation hand task. In conclusion, MDD subjects present with more serious mental rotation deficits specific to the hand than the letter task. Importantly, deficits were more present during the mental transformation in outward rotation angles, thus suggesting that the mental imagery for hands and letters relies on different processing mechanisms which suggest a module that is more complex for the processing of human hands than for letters during mental rotation tasks. Our study emphasises the necessity of distinguishing different levels of impairment of action in MDD subjects.

  7. Spherical shell model description of rotational motion

    NASA Astrophysics Data System (ADS)

    Zuker, A. P.; Retamosa, J.; Poves, A.; Caurier, E.

    1995-10-01

    Exact diagonalizations with a realistic interaction show that configurations with four neutrons in a major shell and four protons in another-or the same-major shell, behave systematically as backbending rotors. The dominance of the q.q component of the interaction is related to an approximate ``quasi-SU3'' symmetry. It is suggested that the onset of rotational motion in the rare earth nuclei is due to the promotion of the eight particle blocks to the major shells above the ones currently filling. Assuming a ``pseudo-SU3'' coupling for the particles in the lower orbits, it is possible to account remarkably well for the observed B(E2) rates at the beginning of the region.

  8. Pure Rotational Spectroscopy of Vinyl Mercaptan

    NASA Astrophysics Data System (ADS)

    Martin-Drumel, Marie-Aline; Zingsheim, Oliver; Thorwirth, Sven; Müller, Holger S. P.; Lewen, Frank; Schlemmer, Stephan

    2014-06-01

    Vinyl mercaptan (ethenethiol, CH_2=CHSH) exists in the gas phase in two distinct rotameric forms, syn (planar) and anti (quasi-planar in the ground vibrational state). The microwave spectra of these two isomers were investigated previously, however not exceeding frequencies of about 65 GHz. In the present investigation, the pure rotational spectra of both species have been investigated at millimeter wavelengths. Vinyl mercaptan was produced in a radiofrequency discharge through a constant flow of ethanedithiol at low pressure. Both syn and anti rotamers were observed and new extensive sets of molecular parameters were obtained. Owing to its close structural relationship to vinyl alcohol and the astronomical abundance of complex sulfur-bearing molecules, vinyl mercaptan is a plausible candidate for future radio astronomical searches. M. Tanimoto et al. J. Mol. Spectrosc. 78, 95--105 & 106--119 (1979)

  9. Rotational period of GQ Lupi

    NASA Astrophysics Data System (ADS)

    Broeg, C.; Schmidt, T. O. B.; Guenther, E.; Gaedke, A.; Bedalov, A.; Neuhäuser, R.; Walter, F. M.

    2007-06-01

    Aims: We wanted to determine the rotation parameters of GQ Lup A, thereby constraining the evolutionary history of the GQ Lup system. Methods: We have undertaken a photometric monitoring campaign on GQ Lup A consisting of two epochs spaced one year apart. We also searched the photometric archives to enlarge the data set. Results: We were able to determine the photometric period (8.45±0.2 days) in both epochs in several photometric bands. This periodicity could also be found in some of the archival data. The combined false-alarm probability is 0.015. The variation is most likely caused by hot spots on the surface of GQ Lup A. This, combined with high-resolution spectra (v sin i) allows calculation of GQ Lup A's inclination (i=27±5°). Radial velocity data also contains this period but is inconclusive. Nevertheless, the RV data supports the interpretation that hot spots cause the photometric variation. We use the known K-band variability, amplitude, and phase of GQ Lup A together with a new image of GQ Lup A+b, taken quasi-simultaneously with our monitoring of the star, to confirm the magnitude and, hence, luminosity of the companion. Based on observations obtained on Cerro Paranal, Chile, in ESO program 075.C-0710(C) and on La Silla, Chile, in ESO programs 074.C-0034(A),075.C-0710(E), 075.C-0710(F), 075.C-0202(A), 076.C-0010(A) as well as with ANDICAM of the SMARTS consortium. Photometry data of epochs I and II are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/468/1039

  10. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    DOEpatents

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  11. Spontaneous symmetry breaking in quasi one dimension

    SciTech Connect

    Satpathi, Urbashi Deo, P. Singha

    2015-06-24

    Electronic charge and spin separation leading to charge density wave and spin density wave is well established in one dimension in the presence and absence of Coulomb interaction. We start from quasi one dimension and show the possibility of such a transition in quasi one dimension as well as in two dimensions by going to a regime where it can be shown for electrons that just interact via Fermi statistics. Such density waves arise due to internal symmetry breaking in a many fermion quantum system. We can extend this result to very wide rings with infinitely many electrons including Coulomb interaction.

  12. The Origin of Monsoon Onset. Part 2; Rotational ITCZ Attractors

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Through various specially designed numerical experiments with an aqua-planet general circulation model and theoretical arguments. Chao showed the existence of multiple quasi-equilibria of the intertropical convergence zone (ITCZ). He also showed that monsoon onset could be interpreted as an abrupt transition between the quasi-equilibria of the ITCZ. He further showed that the origin of these quasi-equilibria is related to two different types of attraction pulling the ITCZ in opposite directions. One type of attraction on the ITCZ is due to earth's rotation, which pulls the ITCZ toward the equator or two equatorial latitudes symmetric with respect to the equator depending on the choice of convection scheme, and the other due to the peak of the sea surface temperature (SST, which is given in the experiments a Gaussian profile in latitude and is uniform in longitude), which pulls the ITCZ toward a latitude just poleward of the SST peak. The strength of the attraction due to the earth's rotation has a highly nonlinear dependence on the latitude and that due to the SST peak has a linear (at least in a relative sense) dependence on the latitude.

  13. Schramm-Loewner (SLE) analysis of quasi two-dimensional turbulent flows

    NASA Astrophysics Data System (ADS)

    Thalabard, Simon

    2012-02-01

    Quasi two-dimensional turbulence can be observed in several cases: for example, in the laboratory using liquid soap films, or as the result of a strong imposed rotation as obtained in three-dimensional large direct numerical simulations. We study and contrast SLE properties of such flows, in the former case in the inverse cascade of energy to large scale, and in the latter in the direct cascade of energy to small scales in the presence of a fully-helical forcing. We thus examine the geometric properties of these quasi 2D regimes in the context of stochastic geometry, as was done for the 2D inverse cascade by Bernard et al. (2006). We show that in both cases the data is compatible with self-similarity and with SLE behaviors, whose different diffusivities can be heuristically determined.

  14. Effect of Multiple Delamination on Free Vibration Behaviour of Quasi-Isotropic Composite Conical Shells

    NASA Astrophysics Data System (ADS)

    Dey, S.; Karmakar, A.

    2013-01-01

    In this paper, a finite element method is employed to investigate the free vibration characteristics of single and multiple delaminated graphite-epoxy quasi-isotropic composite conical shells. The generalized dynamic equilibrium equation is derived from Lagrange's equation of motion neglecting Coriolis effect for moderate rotational speeds. The formulation is based on Mindlin's theory considering eight-noded isoparametric plate bending element. The multipoint constraint algorithm is employed to ensure the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front. The QR iteration algorithm is utilized for solution of standard eigen value problem. Finite element codes are developed to obtain the natural frequencies of single and multiple delaminated quasi-isotropic composite conical shells. The mode shapes for a typical laminate configuration are also depicted. Numerical results obtained are the first known values which could serve as reference solutions for the future investigators.

  15. On quasi-periodic variations of low-energy cosmic rays observed near earth.

    PubMed

    Kudela, Karel; Langer, Ronald

    2015-06-01

    Cosmic ray (CR) may partially, especially at high altitudes, contribute to the dosimetric characteristics. Along with irregular CR variations as Forbush decreases and solar particle events are, the quasi-periodic variations may be of some relevance too. A very short review (with references to original papers) of the present knowledge of various types of such variations is presented, namely (i) diurnal wave, (ii) ~27 d variability due to the solar rotation, (iii) Rieger-type periodicity, and (iv) quasi-biennial oscillations as well as waves on longer time scales related to solar activity and to polarity of magnetic field of the Sun. Variability is illustrated in measurements of secondary CR on the ground including the high-altitude observations at Lomnický štít.

  16. Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR

    SciTech Connect

    Yun, G. S. Choi, M. J.; Lee, J.; Kim, M.; Leem, J.; Nam, Y.; Choe, G. H.; Lee, W.; Park, H. K.; Park, H.; Woo, D. S.; Kim, K. W.; Domier, C. W.; Luhmann, N. C.; Ito, N.; Mase, A.; Lee, S. G.

    2014-11-15

    A second electron cyclotron emission imaging (ECEI) system has been installed on the KSTAR tokamak, toroidally separated by 1/16th of the torus from the first ECEI system. For the first time, the dynamical evolutions of MHD instabilities from the plasma core to the edge have been visualized in quasi-3D for a wide range of the KSTAR operation (B{sub 0} = 1.7∼3.5 T). This flexible diagnostic capability has been realized by substantial improvements in large-aperture quasi-optical microwave components including the development of broad-band polarization rotators for imaging of the fundamental ordinary ECE as well as the usual 2nd harmonic extraordinary ECE.

  17. Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR.

    PubMed

    Yun, G S; Lee, W; Choi, M J; Lee, J; Kim, M; Leem, J; Nam, Y; Choe, G H; Park, H K; Park, H; Woo, D S; Kim, K W; Domier, C W; Luhmann, N C; Ito, N; Mase, A; Lee, S G

    2014-11-01

    A second electron cyclotron emission imaging (ECEI) system has been installed on the KSTAR tokamak, toroidally separated by 1/16th of the torus from the first ECEI system. For the first time, the dynamical evolutions of MHD instabilities from the plasma core to the edge have been visualized in quasi-3D for a wide range of the KSTAR operation (B0 = 1.7∼3.5 T). This flexible diagnostic capability has been realized by substantial improvements in large-aperture quasi-optical microwave components including the development of broad-band polarization rotators for imaging of the fundamental ordinary ECE as well as the usual 2nd harmonic extraordinary ECE.

  18. Quasi-experimental Study Designs Series - Paper 12: Strengthening Global Capacity for Evidence Synthesis of Quasi-experimental Health Systems Research.

    PubMed

    Rockers, Peter C; Tugwell, Peter; Grimshaw, Jeremy; Oliver, Sandy; Atun, Rifat; Røttingen, John-Arne; Fretheim, Atle; Ranson, M Kent; Daniels, Karen; Luiza, Vera Lucia; Bärnighausen, Till

    2017-03-28

    Evidence from quasi-experimental studies is often excluded from systematic reviews of health systems research despite the fact that such studies can provide strong causal evidence when well-conducted. This article discusses global coordination of efforts to institutionalize the inclusion of causal evidence from quasi-experiments in systematic reviews of health systems research. In particular, we are concerned with identifying opportunities for strengthening capacity at the global- and local-level for implementing protocols necessary to ensure that reviews that include quasi-experiments are consistently of the highest quality. We first describe the current state of the global infrastructure that facilitates the production of systematic reviews of health systems research. We identify five important types of actors operating within this infrastructure: review authors; synthesis collaborations that facilitate the review process; synthesis interest groups that supplement the work of the larger collaborations; review funders; and end users, including policymakers. Then, we examine opportunities for intervening to build the capacity of each type of actor to support the inclusion of quasi-experiments in reviews. Lastly, we suggest practical next steps for proceeding with capacity building efforts. Due to the complexity and relative nascence of the field, we recommend a carefully planned and executed approach to strengthening global capacity for the inclusion of quasi-experimental studies in systematic reviews.

  19. Rotational bands in99Sr

    NASA Astrophysics Data System (ADS)

    Pfeiffer, B.; Monnand, E.; Pinston, J. A.; Münzel, J.; Möller, P.; Krumlinde, J.; Ziegert, W.; Kratz, K.-L.

    1984-02-01

    The β-decay of 59 ms99Rb has been studied at OSTIS. As is confirmed by RPA calculations with Nilsson model wave functions, the lowest energy levels in99Sr are consistent with rotational bands built on the [411 3/2], [413 5/2] and [422 3/2] Nilsson neutron configurations at 0, 423 and 1071 keV, respectively. All three bands have similar values of the inertial parameter ħ2/2θ indicating a nearly rigid rotor.

  20. Perturbative Calculation of Quasi-Potential in Non-equilibrium Diffusions: A Mean-Field Example

    NASA Astrophysics Data System (ADS)

    Bouchet, Freddy; Gawȩdzki, Krzysztof; Nardini, Cesare

    2016-06-01

    In stochastic systems with weak noise, the logarithm of the stationary distribution becomes proportional to a large deviation rate function called the quasi-potential. The quasi-potential, and its characterization through a variational problem, lies at the core of the Freidlin-Wentzell large deviations theory (Freidlin and Wentzell, Random perturbations of dynamical systems, 2012). In many interacting particle systems, the particle density is described by fluctuating hydrodynamics governed by Macroscopic Fluctuation Theory (Bertini et al., arXiv:1404.6466 , 2014), which formally fits within Freidlin-Wentzell's framework with a weak noise proportional to 1/√{N}, where N is the number of particles. The quasi-potential then appears as a natural generalization of the equilibrium free energy to non-equilibrium particle systems. A key physical and practical issue is to actually compute quasi-potentials from their variational characterization for non-equilibrium systems for which detailed balance does not hold. We discuss how to perform such a computation perturbatively in an external parameter λ , starting from a known quasi-potential for λ =0. In a general setup, explicit iterative formulae for all terms of the power-series expansion of the quasi-potential are given for the first time. The key point is a proof of solvability conditions that assure the existence of the perturbation expansion to all orders. We apply the perturbative approach to diffusive particles interacting through a mean-field potential. For such systems, the variational characterization of the quasi-potential was proven by Dawson and Gartner (Stochastics 20:247-308, 1987; Stochastic differential systems, vol 96, pp 1-10, 1987). Our perturbative analysis provides new explicit results about the quasi-potential and about fluctuations of one-particle observables in a simple example

  1. Theory of quasi-spherical accretion in X-ray pulsars

    NASA Astrophysics Data System (ADS)

    Shakura, N.; Postnov, K.; Kochetkova, A.; Hjalmarsdotter, L.

    2012-02-01

    A theoretical model for quasi-spherical subsonic accretion on to slowly rotating magnetized neutron stars is constructed. In this model, the accreting matter subsonically settles down on to the rotating magnetosphere forming an extended quasi-static shell. This shell mediates the angular momentum removal from the rotating neutron star magnetosphere during spin-down episodes by large-scale convective motions. The accretion rate through the shell is determined by the ability of the plasma to enter the magnetosphere. The settling regime of accretion can be realized for moderate accretion rates ? g s-1. At higher accretion rates, a free-fall gap above the neutron star magnetosphere appears due to rapid Compton cooling, and accretion becomes highly non-stationary. From observations of the spin-up/spin-down rates (the angular rotation frequency derivative ?, and ? near the torque reversal) of X-ray pulsars with known orbital periods, it is possible to determine the main dimensionless parameters of the model, as well as to estimate the magnetic field of the neutron star. We illustrate the model by determining these parameters for three wind-fed X-ray pulsars GX 301-2, Vela X-1 and GX 1+4. The model explains both the spin-up/spin-down of the pulsar frequency on large time-scales and the irregular short-term frequency fluctuations, which can correlate or anticorrelate with the X-ray flux fluctuations in different systems. It is shown that in real pulsars an almost iso-angular-momentum rotation law with ω˜ 1/R2, due to strongly anisotropic radial turbulent motions sustained by large-scale convection, is preferred.

  2. Supersonic rotation in the Maryland Centrifugal Experiment

    NASA Astrophysics Data System (ADS)

    Messer, Sarah

    rotational Mach numbers between 1 and 2 and imply ∂ rvφ ˜ 106s-1 . Measurements of the loss times found via our circuit model indicate the neutral density is typically a few times 1017m-3 . Calculations based on a zero-dimensional MHD model indicate that the plasma is collisional and highly ionized. In this paper, we outline the direct and indirect evidence for supersonic flow, high (1020m -3) ion density, scarce neutrals (˜1 neutral per 1000 ions), and a plasma state which is at least quasi-stable. Some notes are given on improvements to the models and how these affect the calculations. We also describe planned improvements to the MCX machine and its diagnostics.

  3. STRUCTURE OF UNIFORMLY ROTATING STARS

    SciTech Connect

    Deupree, Robert G.

    2011-07-10

    Zero-age main-sequence models of uniformly rotating stars have been computed for 10 masses between 1.625 and 8 M{sub sun} and for 21 rotation rates from zero to nearly critical rotation. The surface shape is used to distinguish rotation rather than the surface equatorial velocity or the rotation rate. Using the surface shape is close, but not quite equivalent, to using the ratio of the rotation rate to the critical rotation rate. Using constant shape as the rotation variable means that it and the mass are separable, something that is not true for either the rotation rate or surface equatorial velocity. Thus, a number of properties, including the ratio of the effective temperature anywhere on the surface to the equatorial temperature, are nearly independent of the mass of the model, as long as the rotation rate changes in such a way as to keep the surface shape constant.

  4. Comet candidates among quasi-Hilda objects

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.; García-Migani, E.

    2016-05-01

    Aims: We present the results of a search for quasi-Hilda comets. We wanted to find objects that have recently arrived from the Centaur zone that could became active near the perihelion of their orbits. Methods: Two hundred and seventy-seven objects from the ASTORB database were selected following a dynamical criteria to constrain the unstable quasi-Hilda region. These objects were integrated backward 50 000 yr in order to identify those that have recently arrived from the outer regions of the solar system. Results: The backward integration showed that 11 objects could be Centaurs or transneptunian objects that ended their dynamical evolution as quasi-Hilda comets. The dynamical evolution of these objects from a statistical point of view was studied by computing the time-averaged distribution of a number of clones as a function of the aphelion and perihelion distances. All the candidates show a dynamical behavior that is expected for comets injected in the inner solar system from the Centaur or transneptunian regions and reaching the quasi-Hilda region.

  5. Proportional Reasoning of Quasi-Illiterate Adults

    ERIC Educational Resources Information Center

    Alatorre, Silvia; Figueras, Olimpia

    2004-01-01

    The main purpose of this paper is to describe the answers given by adults without primary schooling to different ratio-and rate-comparison tasks. The framework and the analysed data are part of an ongoing research, in which the responses of subjects of different ages and schoolings are studied. The behaviour of quasi-illiterate adults could throw…

  6. Generalized convective quasi-equilibrium principle

    NASA Astrophysics Data System (ADS)

    Yano, Jun-Ichi; Plant, Robert S.

    2016-03-01

    A generalization of Arakawa and Schubert's convective quasi-equilibrium principle is presented for a closure formulation of mass-flux convection parameterization. The original principle is based on the budget of the cloud work function. This principle is generalized by considering the budget for a vertical integral of an arbitrary convection-related quantity. The closure formulation includes Arakawa and Schubert's quasi-equilibrium, as well as both CAPE and moisture closures as special cases. The formulation also includes new possibilities for considering vertical integrals that are dependent on convective-scale variables, such as the moisture within convection. The generalized convective quasi-equilibrium is defined by a balance between large-scale forcing and convective response for a given vertically-integrated quantity. The latter takes the form of a convolution of a kernel matrix and a mass-flux spectrum, as in the original convective quasi-equilibrium. The kernel reduces to a scalar when either a bulk formulation is adopted, or only large-scale variables are considered within the vertical integral. Various physical implications of the generalized closure are discussed. These include the possibility that precipitation might be considered as a potentially-significant contribution to the large-scale forcing. Two dicta are proposed as guiding physical principles for the specifying a suitable vertically-integrated quantity.

  7. Quasi-monolithic tunable optical resonator

    NASA Technical Reports Server (NTRS)

    Arbore, Mark (Inventor); Tapos, Francisc (Inventor)

    2003-01-01

    An optical resonator has a piezoelectric element attached to a quasi-monolithic structure. The quasi-monolithic structure defines an optical path. Mirrors attached to the structure deflect light along the optical path. The piezoelectric element controllably strains the quasi-monolithic structure to change a length of the optical path by about 1 micron. A first feedback loop coupled to the piezoelectric element provides fine control over the cavity length. The resonator may include a thermally actuated spacer attached to the cavity and a mirror attached to the spacer. The thermally actuated spacer adjusts the cavity length by up to about 20 microns. A second feedback loop coupled to the sensor and heater provides a coarse control over the cavity length. An alternative embodiment provides a quasi-monolithic optical parametric oscillator (OPO). This embodiment includes a non-linear optical element within the resonator cavity along the optical path. Such an OPO configuration is broadly tunable and capable of mode-hop free operation for periods of 24 hours or more.

  8. Quasi-Optical SIS Mixer Development

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1997-01-01

    This grant supported our ongoing development of sensitive quasi-optical SIS mixers for the submillimeter band. The technology developed under this grant is now being applied to NASA missions, including the NASA/USRA SOFIA airborne observatory and and the ESA/NASA FIRST/Herschel space astronomy mission.

  9. Quasi-likelihood for Spatial Point Processes

    PubMed Central

    Guan, Yongtao; Jalilian, Abdollah; Waagepetersen, Rasmus

    2014-01-01

    Summary Fitting regression models for intensity functions of spatial point processes is of great interest in ecological and epidemiological studies of association between spatially referenced events and geographical or environmental covariates. When Cox or cluster process models are used to accommodate clustering not accounted for by the available covariates, likelihood based inference becomes computationally cumbersome due to the complicated nature of the likelihood function and the associated score function. It is therefore of interest to consider alternative more easily computable estimating functions. We derive the optimal estimating function in a class of first-order estimating functions. The optimal estimating function depends on the solution of a certain Fredholm integral equation which in practise is solved numerically. The derivation of the optimal estimating function has close similarities to the derivation of quasi-likelihood for standard data sets. The approximate solution is further equivalent to a quasi-likelihood score for binary spatial data. We therefore use the term quasi-likelihood for our optimal estimating function approach. We demonstrate in a simulation study and a data example that our quasi-likelihood method for spatial point processes is both statistically and computationally efficient. PMID:26041970

  10. IO Rotation Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    During its 1979 flyby, Voyager 2 observed Io only from a distance. However, the volcanic activity discovered by Voyager 1 months earlier was readily visible. This sequence of nine color images was collected using the Blue, Green and Orange filters from about 1.2 million kilometers. A 2.5 hour period is covered during which Io rotates 7 degrees.

    Rotating into view over the limb of Io are the plumes of the volcanoes Amirani (top) and Maui (lower). These plumes are very distinct against the black sky because they are being illuminated from behind. Notice that as Io rotates, the proportion of Io which is sunlit decreases greatly. This changing phase angle is because Io is moving between the spacecraft and the Sun.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1985.

  11. Rotating Aperture System

    DOEpatents

    Rusnak, Brian; Hall, James M.; Shen, Stewart; Wood, Richard L.

    2005-01-18

    A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

  12. Chiral rotational spectroscopy

    NASA Astrophysics Data System (ADS)

    Cameron, Robert P.; Götte, Jörg B.; Barnett, Stephen M.

    2016-09-01

    We introduce chiral rotational spectroscopy, a technique that enables the determination of the orientated optical activity pseudotensor components BX X, BY Y, and BZ Z of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample and provides an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral solely by virtue of their isotopic constitution and molecules with multiple chiral centers. A basic design for a chiral rotational spectrometer together with a model of its functionality is given. Our proposed technique offers the more familiar polarizability components αX X, αY Y, and αZ Z as by-products, which could see it find use even for achiral molecules.

  13. Lattice QCD in rotating frames.

    PubMed

    Yamamoto, Arata; Hirono, Yuji

    2013-08-23

    We formulate lattice QCD in rotating frames to study the physics of QCD matter under rotation. We construct the lattice QCD action with the rotational metric and apply it to the Monte Carlo simulation. As the first application, we calculate the angular momenta of gluons and quarks in the rotating QCD vacuum. This new framework is useful to analyze various rotation-related phenomena in QCD.

  14. Rotating bubble membrane radiator

    DOEpatents

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  15. Rotating flexible drag mill

    DOEpatents

    Pepper, W.B.

    1984-05-09

    A rotating parachute for decelerating objects travelling through atmosphere at subsonic or supersonic deployment speeds includes a circular canopy having a plurality of circumferentially arranged flexible panels projecting radially from a solid central disk. A slot extends radially between adjacent panels to the outer periphery of the canopy. Upon deployment, the solid disk diverts air radially to rapidly inflate the panels into a position of maximum diameter. Air impinging on the panels adjacent the panel slots rotates the parachute during its descent. Centrifugal force flattens the canopy into a constant maximum diameter during terminal descent for maximum drag and deceleration.

  16. Rotational Alignment Altered by Source Position Correlations

    NASA Technical Reports Server (NTRS)

    Jacobs, Chris S.; Heflin, M. B.; Lanyi, G. E.; Sovers, O. J.; Steppe, J. A.

    2010-01-01

    In the construction of modern Celestial Reference Frames (CRFs) the overall rotational alignment is only weakly constrained by the data. Therefore, common practice has been to apply a 3-dimensional No-Net-Rotation (NNR) constraint in order to align an under-construction frame to the ICRF. We present evidence that correlations amongst source position parameters must be accounted for in order to properly align a CRF at the 5-10 (mu)as level of uncertainty found in current work. Failure to do so creates errors at the 10-40 (mu)as level.

  17. Solar Cycle Fine Structure and Surface Rotation from Ca II K-Line Time Series Data

    NASA Technical Reports Server (NTRS)

    Scargle, Jeff; Keil, Steve; Worden, Pete

    2011-01-01

    Analysis of three and a half decades of data from the NSO/AFRL/Sac Peak K-line monitoring program yields evidence for four components to the variation: (a) the solar cycle, with considerable fine structure and a quasi-periodicity of 122.4 days; (b) a stochastic process, faster than (a) and largely independent of it, (c) a quasi-periodic signal due to rotational modulation, and of course (d) observational errors (shown to be quite small). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these chromospheric parameters. Time-frequency analysis is especially useful for extracting information about differential rotation, and in particular elucidates the connection between its behavior and fine structure of the solar cycle on approximately one-year time scales. These results further suggest that similar analyses will be useful at detecting and characterizing differential rotation in stars from stellar light-curves such as those being produced at NASA's Kepler observatory.

  18. Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

    SciTech Connect

    Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz

    2009-06-15

    Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten K{alpha} emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

  19. Photofabrication of two-dimensional quasi-crystal patterns on UV-curable molecular azo glass films.

    PubMed

    Guo, Miaocai; Xu, Zeda; Wang, Xiaogong

    2008-03-18

    In this work, two-dimensional surface quasi-crystal patterns were developed by using a novel azobenzene-containing amorphous material (IAC-4), which was newly synthesized for the application. IAC-4 contains a core of isosorbide moiety and two push-pull type azo chromophores as the inner part. The periphery of IAC-4 is functionalized with four cinnamate groups, which can undergo [2+2] photocycloaddition reaction upon UV light irradiation. The molecular design can allow IAC-4 to readily form surface relief structures upon Ar+ laser irradiation, and the formed structures can be further stabilized through a photo-cross-linking reaction induced by UV light irradiation. On the basis of the material, two-dimensional (2D) quasi-crystal structures with different rotation symmetries were successfully fabricated on the IAC-4 films by using the dual-beam multiple exposure technique. In contrast to the approach using photoresist, the quasi-crystal structures were fabricated through the photoinduced mass migration, and no subsequent wet-etch or dry-etch step was required in the process. The quasi-crystal structures with rotation symmetry as high as 60-fold could be feasibly fabricated through this approach. The surface patterns and fabrication method can be potentially applied in areas such as optics, communications, and security inspection.

  20. Investigations of Magnetically Enhanced RIE Reactors with Rotating Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu.; Kushner, Mark J.

    2008-10-01

    In Magnetically Enhanced Reactive Ion Etching (MERIE) reactors, a magnetic field parallel to the substrate enables higher plasma densities and control of ion energy distributions. Since it is difficult to make the B-field uniform across the wafer, the B-field is often azimuthally rotated at a few Hz to average out non-uniformities. The rotation is slow enough that the plasma is in quasi-equilibrium with the instantaneous B-field. For the pressures (10's mTorr or less) and B-fields (10's - 100's G) of interest, electrons are magnetized whereas ions are usually not. The orientation and intersection of the B-field with the wafer are important, as intersecting field lines provide a low resistance path for electron current to the substrate. We report on a modeling study of plasma properties in MERIE reactors having rotating B-fields by investigating a series of quasi-steady states of B-field profiles. To resolve side-to-side variations, computations are performed in Cartesian coordinates. The model, nonPDPSIM, was improved with full tensor conductivities in the fluid portions of the code and v x B forces in the kinetic portions. Results are discussed while varying the orientation and strength of the B-field for electropositive (argon) and electronegative (Ar/CxFy, Ar/Cl2) gas mixtures.

  1. Modelling of quasi-periodic oscillations with wave packets

    NASA Astrophysics Data System (ADS)

    Alpar, M. A.; Yilmaz, A.

    1997-08-01

    Model dispersion relations are introduced to explore power spectra of the normal-branch (NB) and horizontal-branch (HB) quasi-periodic oscillations (QPOs; for reviews see Van der Klis (1989)[ARA&A, 27, 517], (1992) [Proc. of NATO ASI X-Ray Binaries and Recycled Pulsars, eds. E.P.J. Van den Heuvel & S.A. Rappaport, Kluwer, Dordrecht], (1995)[Proc. of NATO ASI The Lives of the Neutron Stars, eds. M.A. Alpar, Ümit Kiziloğlu, & J. van Paradijs, Kluwer, Dordrecht]) of low mass X-ray binaries (LMXBs) in terms of wave packets and to illustrate the presence of frequency bands around the Kepler and beat frequencies. For the NB QPOs wave packets of sound waves in a thick middle disk state, with frequencies determined by the rotation frequency, have wavelengths comparable to the size of the middle disk. For Z-sources on the HB, the wave packets result from disturbances in the inner disk induced by the neutron star magnetic field which rotates at the beat frequency with respect to the inner disk. For both the NB and the HB QPOs, we construct simple model dispersion relations, and show that the QPO peaks in the observed power spectra correspond to reasonable wavelengths and system parameters. The kilohertz QPOs, which were discovered after the original version of this paper was submitted, are also discussed as a possible realization of the Kepler and beat frequency bands. Problems of integrating the kHz and HB QPOs in a disk model are briefly noted. It is tentatively suggested that supersonic and wave propagation regions of the inner disk have complementary functions for the origin of kHz and HB QPOs respectively.

  2. Strongly magnetized rotating dipole in general relativity

    NASA Astrophysics Data System (ADS)

    Pétri, J.

    2016-10-01

    Context. Electromagnetic waves arise in many areas of physics. Solutions are difficult to find in the general case. Aims: We numerically integrate Maxwell equations in a 3D spherical polar coordinate system. Methods: Straightforward finite difference methods would lead to a coordinate singularity along the polar axis. Spectral methods are better suited for such artificial singularities that are related to the choice of a coordinate system. When the radiating object rotates like a star, for example, special classes of solutions to Maxwell equations are worthwhile to study, such as quasi-stationary regimes. Moreover, in high-energy astrophysics, strong gravitational and magnetic fields are present especially around rotating neutron stars. Results: To study such systems, we designed an algorithm to solve the time-dependent Maxwell equations in spherical polar coordinates including general relativity and quantum electrodynamical corrections to leading order. As a diagnostic, we computed the spin-down luminosity expected for these stars and compared it to the classical or non-relativistic and non-quantum mechanical results. Conclusions: Quantum electrodynamics leads to an irrelevant change in the spin-down luminosity even for a magnetic field of about the critical value of 4.4 × 109 T. Therefore the braking index remains close to its value for a point dipole in vacuum, namely n = 3. The same conclusion holds for a general-relativistic quantum electrodynamically corrected force-free magnetosphere.

  3. Effect of rotation on a rotating hot-wire sensor

    NASA Technical Reports Server (NTRS)

    Hah, C.; Lakshminarayana, B.

    1978-01-01

    An investigation was conducted to discern the effects of centrifugal and Coriolis forces on a rotating hot-wire. The probe was calibrated in a wind tunnel as well as in a rotating mode. The effect of rotation was found to be negligibly small. A small change in cold resistance (1.5%) was observed in the rotating wire. The rotation seems to have a negligible effect on the fluid mechanics, heat transfer and material characteristics of the wire. This is a significant conclusion in view of the potential application of the hot-wire probe in a rotating passage (such as turbomachinery).

  4. General Relativistic Elastic Body, Fluid,quasi-rigid Body, Quasi-liquid and Others in Multiple Coordinate Systems

    NASA Astrophysics Data System (ADS)

    Xu, Chongming

    2009-05-01

    The approximation method in multiple coordinate systems at first post Newtonian (1 PN) level has been established by Darmour, Soffel and Xu (Phys. Rev. D(PRD) 43, 3273 (1991);D 45, 1017(1992);D 47, 3124 (1993);D 49, 618 (1994)). Normally, to discuss an astronomical object (e.g. a star in binary systems or the earth in solar system) we need multiple coordinate systems, especially for precise astrometry 1 PN (some time even 2 PN) approximate method is required. As we know up to now the ideas on elastic body, fluid, rigid body and liquid in the framework of Newtonian physics are still very useful for understanding and calculating some practical problems. Although the general relativistic theories of elastic body, general relativistic hydrodynamics and post-Newtonian quasi-rigid body have been discussed by many authors (including our papers (PRD63, 043002(2001); D63, 064001(2001); D68, 064009(2003); D69, 024003(2004); D71,024030 (2005))), but there is no completing discussion on all of these ideas in a unified point view. The applications of these ideas in the general relativity are important in the research fields of astrometry and geophysics, especially in case precise measurements reach so higher level (millimicro arc sec). The extended relativistic versions of these ideas should be revised the Newtonian results. In this paper, we shall give a complete discussion on all of these ideas in 1 PN approximation. We shall clarify the ideas on perfect elastic material, quasi-rigid body, quasi-liquid and so on with some precise mathematical forms. For fluid we show the hydrodynamic equations of a non-perfect fluid in multiple coordinates systems (both local and global).

  5. Rotational properties of the Maria asteroid family

    SciTech Connect

    Kim, M.-J.; Byun, Y.-I.; Choi, Y.-J.; Moon, H.-K.; Hinse, T. C.; Park, J.-H.; Brosch, N.; Kaplan, M.; Kaynar, S.; Uysal, Ö.; Eker, Z.; Güzel, E.; Behrend, R.; Yoon, J.-N.; Mottola, S.; Hellmich, S.

    2014-03-01

    The Maria family is regarded as an old-type (∼3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (N{sub p} /N{sub r} ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.

  6. Rotational Properties of the Maria Asteroid Family

    NASA Astrophysics Data System (ADS)

    Kim, M.-J.; Choi, Y.-J.; Moon, H.-K.; Byun, Y.-I.; Brosch, N.; Kaplan, M.; Kaynar, S.; Uysal, Ö.; Güzel, E.; Behrend, R.; Yoon, J.-N.; Mottola, S.; Hellmich, S.; Hinse, T. C.; Eker, Z.; Park, J.-H.

    2014-03-01

    The Maria family is regarded as an old-type (~3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (Np /Nr ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.

  7. Biomechanics of the incudo-malleolar-joint - Experimental investigations for quasi-static loads.

    PubMed

    Ihrle, S; Gerig, R; Dobrev, I; Röösli, C; Sim, J H; Huber, A M; Eiber, A

    2016-10-01

    Under large quasi-static loads, the incudo-malleolar joint (IMJ), connecting the malleus and the incus, is highly mobile. It can be classified as a mechanical filter decoupling large quasi-static motions while transferring small dynamic excitations. This is presumed to be due to the complex geometry of the joint inducing a spatial decoupling between the malleus and incus under large quasi-static loads. Spatial Laser Doppler Vibrometer (LDV) displacement measurements on isolated malleus-incus-complexes (MICs) were performed. With the malleus firmly attached to a probe holder, the incus was excited by applying quasi-static forces at different points. For each force application point the resulting displacement was measured subsequently at different points on the incus. The location of the force application point and the LDV measurement points were calculated in a post-processing step combining the position of the LDV points with geometric data of the MIC. The rigid body motion of the incus was then calculated from the multiple displacement measurements for each force application point. The contact regions of the articular surfaces for different load configurations were calculated by applying the reconstructed motion to the geometry model of the MIC and calculate the minimal distance of the articular surfaces. The reconstructed motion has a complex spatial characteristic and varies for different force application points. The motion changed with increasing load caused by the kinematic guidance of the articular surfaces of the joint. The IMJ permits a relative large rotation around the anterior-posterior axis through the joint when a force is applied at the lenticularis in lateral direction before impeding the motion. This is part of the decoupling of the malleus motion from the incus motion in case of large quasi-static loads.

  8. 3-D Gaussian beam scattering from a gyromagnetic perforated layer: Quasi-static approach

    NASA Astrophysics Data System (ADS)

    Yachin, Vladimir V.; Zinenko, Tatiana L.

    2016-12-01

    This paper is devoted to the study of the scattering of a three-dimensional (3-D) Gaussian beam with the circular cross section from a double periodic perforated gyromagnetic layer with polarization independent unit-cell, in the quasi-static approximation. We used the plane-wave spectrum representation for Gaussian beam field representation and reduced it to a single integral representation. The phenomena of the lateral beam shift influenced by Faraday rotation and the nearly total beam transmission when passing through gyromagnetic slab biased with an external static magnetic field in the Faraday configuration were considered.

  9. Quasi-equilibrium sequences of binary strange quark stars in general relativity

    NASA Astrophysics Data System (ADS)

    Limousin, Francois; Gondek-Rosińska, Dorota; Gourgoulhon, Eric

    2004-12-01

    Inspiraling compact binaries are expected to be the strongest sources of gravitational waves for VIRGO, LIGO and other laser interferometers. We present the first computations of quasi-equilibrium sequences of compact binaries containing two strange quark stars (which are currently considered as a possible alternative to neutron stars). We study a precoalescing stage in the conformal flatness approximation of general relativity using a multidomain spectral method. A hydrodynamical treatment is performed under the assumption that the flow is either rigidly rotating or irrotational. In each of those cases, we show the differences in the gravitational waves signal from neutron stars described by polytropic equation of state.

  10. Random quasi-phase-matched conversion of broadband radiation in a nonlinear photonic crystal

    SciTech Connect

    Aleksandrovsky, A. S.; Vyunishev, A. M.; Zaitsev, A. I.; Slabko, V. V.

    2010-11-15

    Radiation in the range 187.5-215 nm was generated via random quasi-phase-matched frequency doubling of femtosecond laser pulses in nonlinear photonic crystals of strontium tetraborate. A broad spectrum of fundamental radiation favors the probing of the nonlinear photonic crystal band structure. The red shift of the band structure upon the fundamental wave-vector rotation was observed. No principal limitations of the tuning range at its shorter wavelength boundary from the nonlinear photonic crystal (NPC) material are found. Calculation shows that the NPC structure enables enhancement of nonlinear generation in the vacuum ultraviolet.

  11. Rotation Elastogram Estimation Using Synthetic Transmit Aperture Technique.

    PubMed

    B, Lokesh; Chintada, Bhaskara Rao; Thittai, Arun Kumar

    2017-01-01

    It is well-documented in literature that benign breast lesions, such as fibroadenomas, are loosely bonded to their surrounding tissue and tend to slip under a small quasi-static compression, whereas malignant lesions being firmly bonded to their surrounding tissue do not slip. Recent developments in quasi-static ultrasound elastography have shown that an image of the axial-shear strain distribution can provide information about the bonding condition at the lesion-surrounding tissue boundary. Further studies analyzing the axial-shear strain elastograms revealed that nonzero axial-shear strain values appear inside the lesion, referred to as fill-in, only when a lesion is loosely bonded and asymmetrically oriented to the axis of compression. It was argued that the fill-in observed in axial-shear strain elastogram is a surrogate of the actual rigid-body rotation undergone by such a benign lesion due to slip boundary condition. However, it may be useful and perhaps easy to interpret, if the actual rigid-body rotation of the lesion can itself be visualized directly. To estimate this rotation tensor and its spatial distribution map (called a Rotation Elastogram [RE]), it would be necessary to improve the quality of lateral displacement estimates. Recently, it has been shown in the context of Non-Invasive Vascular Elastography (NIVE) that the Synthetic Transmit Aperture (STA) technique can be adapted for elastography to improve the lateral displacement estimates. Therefore, the focus of this work was to investigate the feasibility of employing the STA technique to improve the lateral displacement estimation and assess the resulting improvement in the RE quality. This investigation was done using both simulation and experimental studies. The image quality metric of contrast-to-noise ratio (CNR) was used to evaluate the quality of rotation elastograms. The results demonstrate that the contrast appeared in RE only in the case of loosely bonded inclusion, and the quality of RE

  12. Compact rotating cup anemometer

    NASA Technical Reports Server (NTRS)

    Wellman, J. B.

    1968-01-01

    Compact, collapsible rotating cup anemometer is used in remote locations where portability and durability are factors in the choice of equipment. This lightweight instrument has a low wind-velocity threshold, is capable of withstanding large mechanical shocks while in its stowed configuration, and has fast response to wind fluctuations.

  13. Rotationally Actuated Prosthetic Hand

    NASA Technical Reports Server (NTRS)

    Norton, William E.; Belcher, Jewell G., Jr.; Carden, James R.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand attached to end of remaining part of forearm and to upper arm just above elbow. Pincerlike fingers pushed apart to degree depending on rotation of forearm. Simpler in design, simpler to operate, weighs less, and takes up less space.

  14. Rotating Science Classrooms.

    ERIC Educational Resources Information Center

    Hogg, Loretta A.

    1980-01-01

    Described is a science classroom program with centralized materials, and assistance and workshops for teachers. Classroom materials on one of five topics rotate every six weeks among five schools. Teachers plan specific units to match the arrival of the materials in their schools. (Author/DS)

  15. Rotational Dynamics with Tracker

    ERIC Educational Resources Information Center

    Eadkhong, T.; Rajsadorn, R.; Jannual, P.; Danworaphong, S.

    2012-01-01

    We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia ("I") of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction ("b") for our system. By omitting the effect of such friction, we derive…

  16. Concepts in crop rotations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop rotations have been a part of civilization since the Middle Ages. With colonization of what would become the United States came new crops of tobacco, cotton, and corn, the first two of which would play significant roles in both the economic beginnings and social fabric of the new country, how ...

  17. Anisotropy in rotating drums

    NASA Astrophysics Data System (ADS)

    Povall, Timothy; McBride, Andrew; Govender, Indresan

    2015-11-01

    An anisotropic relationship between the stress and the strain rate has been observed in two-dimensional simulations of rotating drums. The objective of this work is to investigate the structure of the constitutive relation using three-dimensional discrete-element-method simulations of a rotating drum containing identical rigid spheres for a range of rotational speeds. Anisotropy is quantified from the alignment of the stress and strain rate tensors, with the strain rate computed using a least-squares fit. It is shown that in certain regions there is a strong anisotropic relationship, regardless of the speed of rotation. The effective friction coefficient is examined in order to determine the phase space in which the μ (I) rheology is valid. Lastly, a depth-averaged approach through the flowing layer is employed to determine the relationship between the velocity tangential to the equilibrium surface and the height of the flowing layer. A power-law relationship that approaches linear at high speeds is observed. Supported by NRF/DST Scarce Skills (South Africa).

  18. Rotating Saddle Paul Trap.

    ERIC Educational Resources Information Center

    Rueckner, Wolfgang; And Others

    1995-01-01

    Describes a demonstration in which a ball is placed in an unstable position on a saddle shape. The ball becomes stable when it is rotated above some threshold angular velocity. The demonstration is a mechanical analog of confining a particle in a "Paul Trap". (DDR)

  19. Rotatable stem and lock

    DOEpatents

    Deveney, Joseph E.; Sanderson, Stephen N.

    1984-01-01

    A valve stem and lock include a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

  20. Rotatable stem and lock

    DOEpatents

    Deveney, J.E.; Sanderson, S.N.

    1981-10-27

    A valve stem and lock is disclosed which includes a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

  1. Rotator Cuff Injuries.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    Many baseball players suffer from shoulder injuries related to the rotator cuff muscles. These injuries may be classified as muscular strain, tendonitis or tenosynovitis, and impingement syndrome. Treatment varies from simple rest to surgery, so it is important to be seen by a physician as soon as possible. In order to prevent these injuries, the…

  2. THE ROTATION PROFILE OF SOLAR MAGNETIC FIELDS BETWEEN {+-}60 Degree-Sign LATITUDES

    SciTech Connect

    Shi, X. J.; Xie, J. L.

    2013-08-10

    Through a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields from Carrington Rotation Nos. 1625 to 2129 (from 1975 February to 2012 October), the sidereal rotation rates of solar magnetic fields between {+-}60 Degree-Sign latitudes are investigated. It seems that the temporal variation of rotation rates should be related to the solar cycle phase. The rotation profile of magnetic fields is obtained: the sidereal rotation rates decrease from the equator to mid-latitude and reach their minimum values of about 13.16 deg day{sup -1} (13.17 deg day{sup -1}) at 53 Degree-Sign (54 Degree-Sign ) latitude in the northern (southern) hemisphere, then increase toward higher latitudes. This rotation profile is different from the differential rotation law obtained by Snodgrass from a cross-correlation analysis of daily magnetograms, in which the rotation rates show a steep decrease from the equator to the poles. However, it is much closer to the quasi-rigid rotation law derived by Stenflo from an auto-correlation analysis of daily magnetograms. Some possible interpretations are discussed for the resulting rotation profile.

  3. NEA rotations and binaries

    NASA Astrophysics Data System (ADS)

    Pravec, Petr; Harris, A. W.; Warner, B. D.

    2007-05-01

    Of nearly 3900 near-Earth asteroids known in June 2006, 325 have got estimated rotation periods. NEAs with sizes down to 10 meters have been sampled. Observed spin distribution shows a major changing point around D=200 m. Larger NEAs show a barrier against spin rates >11 d-1 (period P~2.2 h) that shifts to slower rates with increasing equatorial elongation. The spin barrier is interpreted as a critical spin rate for bodies held together by self-gravitation only, suggesting that NEAs larger than 200 m are mostly strenghtless bodies (i.e., with zero tensile strength), so called `rubble piles'. The barrier disappears at D<200 m where most objects rotate too fast to be held together by self-gravitation only, so a non-zero cohesion is implied in the smaller NEAs. The distribution of NEA spin rates in the `rubble pile' range (D>0.2 km) is non-Maxwellian, suggesting that other mechanisms than just collisions worked there. There is a pile up in front of the barrier (P of 2-3 h). It may be related to a spin up mechanism crowding asteroids to the barrier. An excess of slow rotators is seen at P>30 h. The spin-down mechanism has no clear lower limit on spin rate; periods as long as tens of days occur. Most NEAs appear to be in basic spin states with rotation around the principal axis. Excited rotations are present among and actually dominate in slow rotators with damping timescales >4.5 byr. A few tumblers observed among fast rotating coherent objects consistently appear to be more rigid or younger than the larger, rubble-pile tumblers. An abundant population of binary systems among NEAs has been found. The fraction of binaries among NEAs larger than 0.3 km has been estimated to be 15 +/-4%. Primaries of the binary systems concentrate at fast spin rates (periods 2-3 h) and low amplitudes, i.e., they lie just below the spin barrier. The total angular momentum content in the binary systems suggests that they formed at the critical spin rate, and that little or no angular

  4. Non-Axisymmetric Shaping of Tokamaks Preserving Quasi-Axisymmetry

    SciTech Connect

    Long-Poe Ku and Allen H. Boozer

    2009-06-05

    If quasi-axisymmetry is preserved, non-axisymmetric shaping can be used to design tokamaks that do not require current drive, are resilient to disruptions, and have robust plasma stability without feedback. Suggestions for addressing the critical issues of tokamaks can only be validated when presented with sufficient specificity that validating experiments can be designed. The purpose of this paper is provide that specificity for non-axisymmetric shaping. To our knowledge, no other suggestions for the solution of a number of tokamak issues, such as disruptions, have reached this level of specificity. Sequences of three-field-period quasi-axisymmetric plasmas are studied. These sequences address the questions: (1) What can be achieved at various levels of non-axisymmetric shaping? (2) What simplifications to the coils can be achieved by going to a larger aspect ratio? (3) What range of shaping can be achieved in a single experimental facility? The sequences of plasmas found in this study provide a set of interesting and potentially important configurations.

  5. Magnetosheath Filamentary Structures Formed by Ion Acceleration at the Quasi-Parallel Bow Shock

    NASA Technical Reports Server (NTRS)

    Omidi, N.; Sibeck, D.; Gutynska, O.; Trattner, K. J.

    2014-01-01

    Results from 2.5-D electromagnetic hybrid simulations show the formation of field-aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi-parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi-parallel sheath; however, they may extend to the quasi-perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi-parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi-parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

  6. Magnetosheath filamentary structures formed by ion acceleration at the quasi-parallel bow shock

    NASA Astrophysics Data System (ADS)

    Omidi, N.; Sibeck, D.; Gutynska, O.; Trattner, K. J.

    2014-04-01

    Results from 2.5-D electromagnetic hybrid simulations show the formation of field-aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi-parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi-parallel sheath; however, they may extend to the quasi-perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi-parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi-parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

  7. Rotational excitations in two-color photoassociation

    NASA Astrophysics Data System (ADS)

    Hazra, Jisha; Deb, Bimalendu

    2010-02-01

    We show that it is possible to excite higher rotational states J>2 in ultracold photoassociation by two laser fields. Usually higher J states are suppressed in photoassociation at ultracold temperatures in the regime of Wigner threshold laws. We propose a scheme in which one strong laser field drives photoassociation transition close to either J=1 or J=2 rotational state of a particular vibrational level of an electronically excited molecule. The other laser field is tuned near photoassociation resonance with J>2 rotational levels of the same vibrational state. The strong laser field induces a strong continuum-bound dipole coupling. The resulting dipole force between two colliding atoms modifies the continuum states forming continuum-bound dressed states with a significant component of higher partial waves in the continuum configuration. When the second laser is scanned near the resonance of the higher J states, these states become populated due to photoassociative transitions from the modified continuum.

  8. Three dimensional dynamics of rotating structures under mixed boundary conditions

    NASA Astrophysics Data System (ADS)

    Bediz, Bekir; Romero, L. A.; Ozdoganlar, O. Burak

    2015-12-01

    This paper presents the spectral-Tchebychev (ST) technique for solution of three dimensional (3D) dynamics of rotating structures. In particular, structures that exhibit coupled dynamic response require a 3D modeling approach to capture their dynamic behavior. Rotational motions further complicate this behavior, inducing coriolis, centrifugal softening, and (nonlinear) stress-stiffening effects. Therefore, a 3D solution approach is needed to accurately capture the rotational dynamics. The presented 3D-ST technique provides a fast-converging and precise solution approach for rotational dynamics of structures with complex geometries and mixed boundary conditions. Specifically, unlike finite elements techniques, the presented technique uses a series expansion approach considering distributed-parameter system equations: The integral boundary value problem for rotating structures is discretized using the spectral-Tchebychev approach. To simplify the domain of the structures, cross-sectional and rotational transformations are applied to problems with curved cross-section and pretwisted geometry. The nonlinear terms included in the integral boundary value problem are linearized around an equilibrium solution using the quasi-static method. As a result, mass, damping, and stiffness matrices, as well as a forcing vector, are obtained for a given rotating structure. Several case studies are then performed to demonstrate the application and effectiveness of the 3D-ST solution. For each problem, the natural frequencies and modes shapes from the 3D-ST solution are compared to those from the literature (when available) and to those from a commercial finite elements software. The case studies include rotating/spinning parallelepipeds under free and mixed boundary conditions, and a cantilevered pretwisted beam (i.e., rotating blade) with an airfoil geometry rotating on a hub. It is seen that the natural frequencies and mode shapes from the 3D-ST technique differ from those from the

  9. Invariant curves of quasi-periodic reversible mappings

    NASA Astrophysics Data System (ADS)

    Liu, Bin

    2005-03-01

    We deal with the existence of invariant curves of planar reversible mappings which are quasi-periodic in one of the spatial variables. As applications, we will study the existence of quasi-periodic solutions and the boundedness of solutions for a pendulum-type equation and an asymmetric oscillator depending quasi-periodically on time.

  10. Radial velocity planet detection biases at the stellar rotational period

    NASA Astrophysics Data System (ADS)

    Vanderburg, Andrew; Plavchan, Peter; Johnson, John Asher; Ciardi, David R.; Swift, Jonathan; Kane, Stephen R.

    2016-07-01

    Future generations of precise radial velocity (RV) surveys aim to achieve sensitivity sufficient to detect Earth mass planets orbiting in their stars' habitable zones. A major obstacle to this goal is astrophysical RV noise caused by active areas moving across the stellar limb as a star rotates. In this paper, we quantify how stellar activity impacts exoplanet detection with radial velocities as a function of orbital and stellar rotational periods. We perform data-driven simulations of how stellar rotation affects planet detectability and compile and present relations for the typical time-scale and amplitude of stellar RV noise as a function of stellar mass. We show that the characteristic time-scales of quasi-periodic RV jitter from stellar rotational modulations coincides with the orbital period of habitable-zone exoplanets around early M-dwarfs. These coincident periods underscore the importance of monitoring the targets of RV habitable-zone planet surveys through simultaneous photometric measurements for determining rotation periods and activity signals, and mitigating activity signals using spectroscopic indicators and/or RV measurements at different wavelengths.

  11. Vortex patterns in moderately rotating Bose-condensed gas

    NASA Astrophysics Data System (ADS)

    Imran, Mohd; Ahsan, M. A. H.

    2017-02-01

    Using exact diagonalization, we investigate the many-body ground state for regular vortex patterns in a rotating Bose-condensed gas of N spinless particles, confined in a quasi-two-dimensional harmonic trap and interacting repulsively via finite-range Gaussian potential. The N-body Hamiltonian matrix is diagonalized in given subspaces of quantized total angular momentum L z , to obtain the lowest-energy eigenstate. Further, the internal structure of these eigenstates is analyzed by calculating the corresponding conditional probability distribution. Specifically, the quantum mechanically stable as well as unstable states in a co-rotating frame are examined in the moderately rotating regime corresponding to angular momenta 4N≤slant {L}z< 5N for N = 16 bosons. In response to externally impressed rotation, the patterns of singly quantized vortices are formed, shaping into canonical polygons with a central vortex at the trap center. The internal structure of unstable states reveals the mechanism of entry, nucleation and pattern formation of vortices with structural phase transition, as the condensate goes from one stable vortical state to the other. The stable polygonal vortex patterns having discrete p-fold rotational symmetry with p = 5 and p = 6 are observed. The hexagonal vortex pattern with p = 6 symmetry is a precursor to the triangular vortex lattice of singly quantized vortices in the thermodynamic limit. For unstable states, quantum melting of vortex patterns due to uncertainty in positions of individual vortices, is also briefly discussed.

  12. Recently Discovered Features of the Quasi Coherent Mode

    NASA Astrophysics Data System (ADS)

    Montag, P.; Coppi, B.; Sugiyama, L.; Zhou, T.

    2014-10-01

    The Quasi Coherent Mode (QCM) is observed when the EDA H-Confinement regime is produced by the Alcator C-Mod machine and has been found to 1) have a phase velocity in the direction of the electron diamagnetic velocity in the plasma reference frame 2) involve relatively high electron temperature fluctuations 3) be highly localized radially at the outer edge of the plasma column beyond the Last Closed Magnetic Surface (LCMS). A novel theoretical model is given for which; a) the relevant resistive mode driving factor is the sharp plasma pressure gradient that develops at the edge when the plasma enters the EDA H-Regime; b) the known ``disconnected mode approximation'' cannot be applied to characterize the mode topology as the rotational transform ι Ψ = 1 / q Ψ = 0 on the LCMS; c) the mode localization in the poloidal direction (ballooning) is related to the limited region around the equatorial plane where the pitch of the magnetic field is about constant. The observed temperature fluctuations are consistent with the low values of the local longitudinal thermal conductivity. Sponsored in part by the US DOE.

  13. Microstructural Characterisation of Jute/Epoxy Quasi-Unidirectional Composites

    NASA Astrophysics Data System (ADS)

    Virk, Amandeep Singh; Hall, Wayne; Summerscales, John

    2014-12-01

    The elastic properties of a composite can be predicted by micromechanical models based on the properties of the individual constituent materials of the composite and their geometrical characteristics. This paper presents a novel methodology using image analysis to determine (a) the fibre volume fraction and (b) the fibre orientation distribution factor of quasi-unidirectional jute fibre reinforced epoxy resin composites. For fibre volume fraction, digital micrographs were smoothed to reduce noise in the image, an intensity histogram informed selection of the threshold intensity for conversion to a binary image, the image was morphologically closed and opened to remove internal voids and small features respectively and the fibre volume fraction was calculated as the ratio of the detected fibre area to the total image area. For fibre orientation, the image was sharpened with Contrast-Limited Adaptive Histogram Equalisation, a threshold was set for conversion to binary and then a masking image was rotated at a number of seed points over the image to find the angles with the minimum sum of intensity at each point. The data generated was then used to validate new rules-of-mixture equations for natural fibre composites.

  14. Rotation of solar magnetic fields for the current solar cycle 24

    SciTech Connect

    Shi, X. J.; Xie, J. L.

    2014-11-01

    The rotation of solar magnetic fields for the current solar cycle 24 is investigated through a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields during Carrington rotation numbers 2076-2146 (2008 October to 2014 January). The sidereal rotation rates of positive and negative magnetic fields at some latitudes are shown, and it can be found that the positive (negative) fields generally rotate faster than the negative (positive) fields in the southern (northern) hemisphere at low latitudes. The mean rotation profiles of total, positive, and negative magnetic fields between ±60° latitudes in the time interval are also obtained. It should be noted that both of the mean rotation profiles of the positive and negative magnetic fields, as well as the mean rotation profile of the total magnetic field, exhibit a quasi-rigid rotation at latitudes above about 55°. The mean rotation rates of the positive (negative) polarity reach their maximum values at about 9°(6)° latitude in the southern (northern) hemisphere. The mean rotation profile of the total magnetic field displays an obvious north-south asymmetry, where the rotation seems to be more differential in the northern hemisphere. The latitude variation in the rotation rate differences between positive and negative magnetic fields is further studied, and it is found that magnetic fields with the same polarity as the leading sunspots at a given hemisphere rotate faster than those with the opposite polarity, except for the zones around 52° latitude of the southern hemisphere and around 35° latitude of the northern hemisphere. The implication of these results is discussed. It is clear that the obtained results can provide some observational constraints on the theoretical research of the mechanisms of differential rotation and solar cycle.

  15. Rotationally resolved infrared spectroscopy of adamantane

    NASA Astrophysics Data System (ADS)

    Pirali, O.; Boudon, V.; Oomens, J.; Vervloet, M.

    2012-01-01

    We present the first rotationally resolved spectra of adamantane (C10H16) applying gas-phase Fourier transform infrared (IR) absorption spectroscopy. High-resolution IR spectra are recorded in the 33-4500 cm-1range using as source of IR radiation both synchrotron radiation (at the AILES beamline of the SOLEIL synchrotron) as well as a classical globar. Adamantane is a spherical top molecule with tetrahedral symmetry (Td point group) and has no permanent dipole moment in its vibronic ground state. Of the 72 fundamental vibrational modes in adamantane, only 11 are IR active. Here we present rotationally resolved spectra for seven of them: ν30, ν28, ν27, ν26, ν25, ν24, and ν23. The typical rotational structure of spherical tops is observed and analyzed using the STDS software developed in the Dijon group, which provides the first accurate energy levels and rotational constants for seven fundamental modes. Rotational levels with quantum numbers as high as J = 107 have been identified and included in the fit leading to a typical standard deviation of about 10-3 cm-1.

  16. A quasi-linear analysis of the impurity effect on turbulent momentum transport and residual stress

    NASA Astrophysics Data System (ADS)

    Ko, S. H.; Jhang, Hogun; Singh, R.

    2015-08-01

    We study the impact of impurities on turbulence driven intrinsic rotation (via residual stress) in the context of the quasi-linear theory. A two-fluid formulation for main and impurity ions is employed to study ion temperature gradient modes in sheared slab geometry modified by the presence of impurities. An effective form of the parallel Reynolds stress is derived in the center of mass frame of a coupled main ion-impurity system. Analyses show that the contents and the radial profile of impurities have a strong influence on the residual stress. In particular, an impurity profile aligned with that of main ions is shown to cause a considerable reduction of the residual stress, which may lead to the reduction of turbulence driven intrinsic rotation.

  17. A quasi-linear analysis of the impurity effect on turbulent momentum transport and residual stress

    SciTech Connect

    Ko, S. H. Jhang, Hogun; Singh, R.

    2015-08-15

    We study the impact of impurities on turbulence driven intrinsic rotation (via residual stress) in the context of the quasi-linear theory. A two-fluid formulation for main and impurity ions is employed to study ion temperature gradient modes in sheared slab geometry modified by the presence of impurities. An effective form of the parallel Reynolds stress is derived in the center of mass frame of a coupled main ion-impurity system. Analyses show that the contents and the radial profile of impurities have a strong influence on the residual stress. In particular, an impurity profile aligned with that of main ions is shown to cause a considerable reduction of the residual stress, which may lead to the reduction of turbulence driven intrinsic rotation.

  18. Wave-driven Rotation in Supersonically Rotating Mirrors

    SciTech Connect

    A. Fetterman and N.J. Fisch

    2010-02-15

    Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

  19. Quasi-Neutral Theory of Epidemic Outbreaks

    PubMed Central

    Pinto, Oscar A.; Muñoz, Miguel A.

    2011-01-01

    Some epidemics have been empirically observed to exhibit outbreaks of all possible sizes, i.e., to be scale-free or scale-invariant. Different explanations for this finding have been put forward; among them there is a model for “accidental pathogens” which leads to power-law distributed outbreaks without apparent need of parameter fine tuning. This model has been claimed to be related to self-organized criticality, and its critical properties have been conjectured to be related to directed percolation. Instead, we show that this is a (quasi) neutral model, analogous to those used in Population Genetics and Ecology, with the same critical behavior as the voter-model, i.e. the theory of accidental pathogens is a (quasi)-neutral theory. This analogy allows us to explain all the system phenomenology, including generic scale invariance and the associated scaling exponents, in a parsimonious and simple way. PMID:21760930

  20. A Compact Quasi-axisymmetric Stellarator Reactor

    SciTech Connect

    L.P. Ku; the ARIES-CS Team

    2003-10-20

    We report the progress made in assessing the potential of compact, quasi-axisymmetric stellarators as power-producing reactors. Using an aspect ratio A=4.5 configuration derived from NCSX and optimized with respect to the quasi-axisymmetry and MHD stability in the linear regime as an example, we show that a reactor of 1 GW(e) maybe realizable with a major radius *8 m. This is significantly smaller than the designs of stellarator reactors attempted before. We further show the design of modular coils and discuss the optimization of coil aspect ratios in order to accommodate the blanket for tritium breeding and radiation shielding for coil protection. In addition, we discuss the effects of coil aspect ratio on the peak magnetic field in the coils.

  1. Quasi-Hamiltonian structure and Hojman construction

    NASA Astrophysics Data System (ADS)

    Carinena, Jose F.; Guha, Partha; Ranada, Manuel F.

    2007-08-01

    Given a smooth vector field [Gamma] and assuming the knowledge of an infinitesimal symmetry X, Hojman [S. Hojman, The construction of a Poisson structure out of a symmetry and a conservation law of a dynamical system, J. Phys. A Math. Gen. 29 (1996) 667-674] proposed a method for finding both a Poisson tensor and a function H such that [Gamma] is the corresponding Hamiltonian system. In this paper, we approach the problem from geometrical point of view. The geometrization leads to the clarification of several concepts and methods used in Hojman's paper. In particular, the relationship between the nonstandard Hamiltonian structure proposed by Hojman and the degenerate quasi-Hamiltonian structures introduced by Crampin and Sarlet [M. Crampin, W. Sarlet, Bi-quasi-Hamiltonian systems, J. Math. Phys. 43 (2002) 2505-2517] is unveiled in this paper. We also provide some applications of our construction.

  2. Optimized dynamic rotation with wedges.

    PubMed

    Rosen, I I; Morrill, S M; Lane, R G

    1992-01-01

    Dynamic rotation is a computer-controlled therapy technique utilizing an automated multileaf collimator in which the radiation beam shape changes dynamically as the treatment machine rotates about the patient so that at each instant the beam shape matches the projected shape of the target volume. In simple dynamic rotation, the dose rate remains constant during rotation. For optimized dynamic rotation, the dose rate is varied as a function of gantry angle. Optimum dose rate at each gantry angle is computed by linear programming. Wedges can be included in the optimized dynamic rotation therapy by using additional rotations. Simple and optimized dynamic rotation treatment plans, with and without wedges, for a pancreatic tumor have been compared using optimization cost function values, normal tissue complication probabilities, and positive difference statistic values. For planning purposes, a continuous rotation is approximated by static beams at a number of gantry angles equally spaced about the patient. In theory, the quality of optimized treatment planning solutions should improve as the number of static beams increases. The addition of wedges should further improve dose distributions. For the case studied, no significant improvements were seen for more than 36 beam angles. Open and wedged optimized dynamic rotations were better than simple dynamic rotation, but wedged optimized dynamic rotation showed no definitive improvement over open beam optimized dynamic rotation.

  3. Quasi-exactly solvable quasinormal modes

    SciTech Connect

    Ho, C.-L.; Cho, H.-T.

    2007-11-20

    We consider quasinormal modes with complex energies from the point of view of the theory of quasi-exactly solvable (QES) models. We demonstrate that it is possible to find new potentials which admit exactly solvable or QES quasinormal modes by suitable complexification of parameters defining the QES potentials. Particularly, we obtain one QES and four exactly solvable potentials out of the five one-dimensional QES systems based on the sl(2) algebra.

  4. Quasi quantum group covariant q-oscillators

    NASA Astrophysics Data System (ADS)

    Schomerus, Volker

    1993-07-01

    If q is a pth rooty of unit there exists a quasi-co-associative truncated quantum group algebra U qT(sl 2) whose indecomposable representations ar the physical representations of U q(sl 2), whose co-product yields the truncated tensor product of physical representations of U q(sl 2), and whose R-matrix satisfies quasi Yang-Baxter equations. These truncated quantum group algebras are examples of weak quasi quantum group algebras [2]. For primitive pth roots q, q = e 2 πi/ p, we consider a two-dimensional q-oscillator which admits U qT(sl 2) as a symmetry algebra. Its wave function lie in a space FqT of "functions on the truncated quantum plane", i.e. of polynomials in noncommuting complex coordinate functions za, on which multiplication operators Za and the elements of U qT(sl 2) can act. This illustrates the concept of quasi quantum planes [1]. Due to the truncation, the Hilbert space of states is finite dimensional. The subspaces FR(n) of monomials in za of nth degree vanish for n⩾ p - 1, and FT(n) carries the (2 J+1)-dimensional irreducible representation of UqT( sl2) if n = 2J, J = 0, {1}/{2},…, {1}/{2}(p-2) . Partial derivatives ∂a are introduced. We find a ∗-operation on the algebra of multiplication operators, Zi and derivatives ∂b such that the adjoints Z a∗ act as differentiation on the truncated quantum plane. Multiplication operators Za ("creation operators") and their adjoints ("annihilation operators") obey q {-1}/{2}- commutation relations. The ∗-operation is used to determine a positive definite scalar product on the truncated quantum plane FqT. Some natural candidates of hamiltonians for the q-oscillators are determined.

  5. Characteristics of Quasi-Molecular State Interaction

    SciTech Connect

    Devdariani, A.; Dalimier, E.; Kereselidze, T.; Noselidze, I.; Rebentrost, F.; Sauvan, P.

    2008-10-22

    The quasi-molecular dipole transition moments have been considered analytically within the framework of the two-state approximation with particular emphasis on their roots (zeros) on spectral manifestations of the roots in the adiabatic diabatic limits. The interrelation between the spectral features the non-adiabatic transitions found in [1] has been demonstrated for excited state charge exchange Al{sup +12}(n = 4)+C{sup +6}{yields}Al{sup +13}+C{sup +5}(n = 2)

  6. Quasi-Fibonacci Numbers of Order 11

    NASA Astrophysics Data System (ADS)

    Wituła, Roman; Słota, Damian

    2007-08-01

    In this paper we introduce and investigate the so-called quasi-Fibonacci numbers of order 11 . These numbers are defined by five conjugate recurrence equations of order five. We study some relations and identities concerning these numbers. We present some applications to the decomposition of some polynomials. Many of the identities presented here are the generalizations of the identities characteristic for general recurrence sequences of order three given by Rabinowitz.

  7. Quasi-neutrality in the polar cusp

    NASA Astrophysics Data System (ADS)

    Burch, J. L.

    1985-07-01

    Data from the High Altitude Plasma Instrument on Dynamics Explorer have shown a remarkably close correspondence between the densities of suprathermal electrons and positive ions at altitudes between 16,000 and 23,000 km in the polar cusp. It is argued that this quasi-neutrality results from an ambipolar electric field at the magnetopause, which allows the entry of magnetosheath electrons only to the extent required to balance the charge carried by the positive ions.

  8. Reformulation of quasi-linear theory.

    NASA Technical Reports Server (NTRS)

    Kaufman, A. N.

    1972-01-01

    Standard plasma quasi-linear theory is reformulated on the basis of a classical quantum derivation proceeding from the Vlasov equation and dealing only with frequency, wavenumber, and velocity. The wave amplitudes are assumed to be weakly time-dependent, and no distinction is made between growing and decaying waves. The proposed method leads to no negative diffusivity of 'fake' diffusion. By appropraite treatment of nonresonant interaction, expressions are obtained for wave energy and momentum.

  9. Rigid rotators. [deriving the time-independent energy states associated with rotational motions of the molecule

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The two-particle, steady-state Schroedinger equation is transformed to center of mass and internuclear distance vector coordinates, leading to the free particle wave equation for the kinetic energy motion of the molecule and a decoupled wave equation for a single particle of reduced mass moving in a spherical potential field. The latter describes the vibrational and rotational energy modes of the diatomic molecule. For fixed internuclear distance, this becomes the equation of rigid rotator motion. The classical partition function for the rotator is derived and compared with the quantum expression. Molecular symmetry effects are developed from the generalized Pauli principle that the steady-state wave function of any system of fundamental particles must be antisymmetric. Nuclear spin and spin quantum functions are introduced and ortho- and para-states of rotators, along with their degeneracies, are defined. Effects of nuclear spin on entropy are deduced. Next, rigid polyatomic rotators are considered and the partition function for this case is derived. The patterns of rotational energy levels for nonlinear molecules are discussed for the spherical symmetric top, for the prolate symmetric top, for the oblate symmetric top, and for the asymmetric top. Finally, the equilibrium energy and specific heat of rigid rotators are derived.

  10. A Fully Lane-consistent Dispersive Optical Model Potential for Even Fe Isotopes Based on a Soft-rotator Model

    NASA Astrophysics Data System (ADS)

    Sun, W.; Li, R.; Soukhovitskiı˜, E. Sh.; Quesada, J. M.; Capote, R.

    2014-04-01

    A fully Lane-consistent dispersive coupled-channel optical model (DCCOM) potential is derived that describes nucleon induced reactions on even iron isotopes. Low-lying structure of excited levels in iron even-even isotopes is described by a soft-rotator model that allows for dynamical deformation around the spherical shape. Soft-rotator Hamiltonian parameters are adjusted to reproduce the experimental energies of the low-lying collective levels of these isotopes. The comprehensive experimental database used in the fitting process included all scattering data for neutron and proton scattering up to 200 MeV. Employed Lane-consistent formalism allows deriving a potential fully symmetric for neutrons and protons. Lane consistency of the derived potential was validated by describing the quasi-elastic (p,n) scattering with excitation of IAS states. An exact approach for calculation of inelastic analyzing powers is derived. Calculated elastic and inelastic analyzing powers both for neutron and proton induced reactions were shown to be in good agreement with experimental data demonstrating the reliability of dispersive spin-orbit potential.

  11. Generalized Convective Quasi-Equilibrium Closure

    NASA Astrophysics Data System (ADS)

    Yano, Jun-Ichi; Plant, Robert

    2016-04-01

    Arakawa and Schubert proposed convective quasi-equilibrium as a basic principle for closing their spectrum mass-flux convection parameterization. In deriving this principle, they show that the cloud work function is a key variable that controls the growth of convection. Thus, this closure hypothesis imposes a steadiness of the cloud work function tendency. This presentation shows how this principle can be generalized so that it can also encompasses both the CAPE and the moisture-convergence closures. Note that the majority of the current mass-flux convection parameterization invokes a CAPE closure, whereas the moisture-convergence closure was extremely popular historically. This generalization, in turn, includes both closures as special cases of convective quasi-equilibrium. This generalization further suggests wide range of alternative possibilities for convective closure. In general, a vertical integral of any function depending on both large-scale and convective-scale variables can be adopted as an alternative closure variables, leading to an analogous formulation as Arakawa and Schubert's convective quasi-equilibrium formulation. Among those, probably the most fascinating possibility is to take a vertical integral of the convective-scale moisture for the closure. Use of a convective-scale variable for closure has a particular appeal by not suffering from a loss of predictability of any large-scale variables. That is a main problem with any of the current convective closures, not only for the moisture-convergence based closure as often asserted.

  12. Direct determination of state-to-state rotational energy transfer rate constants via a Raman-Raman double resonance technique: ortho-acetylene in v(2)=1 at 155 K.

    PubMed

    Doménech, José L; Martínez, Raúl Z; Ramos, Angel; Bermejo, Dionisio

    2010-04-21

    A new technique for the direct determination of state-to-state rotational energy transfer rate constants in the gas phase is presented. It is based on two sequential stimulated Raman processes: the first one prepares the sample in a single rotational state of an excited vibrational level, and the second one, using the high resolution quasi-continuous stimulated Raman-loss technique, monitors the transfer of population to other rotational states of the same vibrational level as a function of the delay between the pump and the probe stages. The technique is applied to the odd-J rotational states of v(2)=1 acetylene at 155 K. The experimental layout, data acquisition, retrieval procedures, and numerical treatment are described. The quantity and quality of the data are high enough to allow a direct determination of the state-to-state rate constant matrix from a fit of the experimental data, with the only conditions of detailed balance and of a closed number of states. The matrix obtained from this direct fit is also compared with those obtained using some common fitting and scaling laws.

  13. Soil compaction across the old rotation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluating soil compaction levels across the Old Rotation, the world’s oldest continuous cotton (Gossypium hirsutum L.) experiment, has not been conducted since the experiment transitioned to conservation tillage and high residue cover crops with and without irrigation. Our objective was to charact...

  14. The Rotating Morse-Pekeris Oscillator Revisited

    ERIC Educational Resources Information Center

    Zuniga, Jose; Bastida, Adolfo; Requena, Alberto

    2008-01-01

    The Morse-Pekeris oscillator model for the calculation of the vibration-rotation energy levels of diatomic molecules is revisited. This model is based on the realization of a second-order exponential expansion of the centrifugal term about the minimum of the vibrational Morse oscillator and the subsequent analytical resolution of the resulting…

  15. A Translational Polarization Rotator

    NASA Technical Reports Server (NTRS)

    Chuss, David T.; Wollack, Edward J.; Pisano, Giampaolo; Ackiss, Sheridan; U-Yen, Kongpop; Ng, Ming wah

    2012-01-01

    We explore a free-space polarization modulator in which a variable phase introduction between right- and left-handed circular polarization components is used to rotate the linear polarization of the outgoing beam relative to that of the incoming beam. In this device, the polarization states are separated by a circular polarizer that consists of a quarter-wave plate in combination with a wire grid. A movable mirror is positioned behind and parallel to the circular polarizer. As the polarizer-mirror distance is separated, an incident liear polarization will be rotated through an angle that is proportional to the introduced phase delay. We demonstrate a prototype device that modulates Stokes Q and U over a 20% bandwidth.

  16. A call for rotators

    NASA Astrophysics Data System (ADS)

    Mountain, Gregory

    “Needed: highly motivated geoscientists willing to slow the pace of their research for 1-2 years while managing federal government support of their discipline. Assured: change of perspective; no change in pay. Contact your National Science Foundation Program Director for details.—No, this isn't an NSF job announcement; this is an open letter to members of the Earth science community from a recently “retired” NSF rotator concerned by the small number of researchers interested in a Washington tour. I learned firsthand the extent to which an individual in this position is entrusted with decision-making powers, and as a result, I believe that each of us in the research community should feel responsible for ensuring that highly qualified people serve as rotators.

  17. Rotatable seal assembly

    DOEpatents

    Logan, Clinton M.; Garibaldi, Jack L.

    1982-01-01

    An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an O-ring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers.

  18. Rotational spectrum of tryptophan

    NASA Astrophysics Data System (ADS)

    Sanz, M. Eugenia; Cabezas, Carlos; Mata, Santiago; Alonso, Josè L.

    2014-05-01

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the 14N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O-H...N hydrogen bond in the side chain and a N-H...π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  19. Rotational spectrum of tryptophan

    SciTech Connect

    Sanz, M. Eugenia Cabezas, Carlos Mata, Santiago Alonso, Josè L.

    2014-05-28

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the {sup 14}N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O–H···N hydrogen bond in the side chain and a N–H···π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  20. On rotational conical flow

    NASA Technical Reports Server (NTRS)

    Ferrari, Carlo

    1952-01-01

    Some general properties of isoenergetic rotational conical fields are determined. For such fields, provided the physical parameters of the fluid flow are known on a conical reference surface, it being understood that they satisfy certain imposed conditions, it is shown how to construct the hodographs in the various meridional semiplanes, as the envelope of either the tangents to the hodographs or of the osculatory circles.

  1. Rotating housing turbine

    DOEpatents

    Allouche, Erez; Jaganathan, Arun P.

    2016-10-11

    The invention is a new turbine structure having a housing that rotates. The housing has a sidewall, and turbine blades are attached to a sidewall portion. The turbine may be completely open in the center, allowing space for solids and debris to be directed out of the turbine without jamming the spinning blades/sidewall. The turbine may be placed in a generator for generation of electrical current.

  2. How good a clock is rotation? The stellar rotation-mass-age relationship for old field stars

    SciTech Connect

    Epstein, Courtney R.; Pinsonneault, Marc H. E-mail: pinsono@astronomy.ohio-state.edu

    2014-01-10

    The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with a rotation distribution from open cluster M37. Our predicted rotation-mass-age relationship shows significant zero-point offsets compared to an alternative angular momentum loss law and published gyrochronology relations. Systematic errors at the 30% level are permitted by current data, highlighting the need for empirical guidance. We identify two fundamental sources of uncertainty that limit the precision of rotation-based ages and quantify their impact. Stars are born with a range of rotation rates, which leads to an age range at fixed rotation period. We find that the inherent ambiguity from the initial conditions is important for all young stars, and remains large for old stars below 0.6 M {sub ☉}. Latitudinal surface differential rotation also introduces a minimum uncertainty into rotation period measurements and, by extension, rotation-based ages. Both models and the data from binary star systems 61 Cyg and α Cen demonstrate that latitudinal differential rotation is the limiting factor for rotation-based age precision among old field stars, inducing uncertainties at the ∼2 Gyr level. We also examine the relationship between variability amplitude, rotation period, and age. Existing ground-based surveys can detect field populations with ages as old as 1-2 Gyr, while space missions can detect stars as old as the Galactic disk. In comparison with other techniques for measuring the ages of lower main sequence stars, including geometric parallax and asteroseismology, rotation-based ages have the potential to be the most precise chronometer for 0.6-1.0 M {sub ☉} stars.

  3. How Good a Clock is Rotation? The Stellar Rotation-Mass-Age Relationship for Old Field Stars

    NASA Astrophysics Data System (ADS)

    Epstein, Courtney R.; Pinsonneault, Marc H.

    2014-01-01

    The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with a rotation distribution from open cluster M37. Our predicted rotation-mass-age relationship shows significant zero-point offsets compared to an alternative angular momentum loss law and published gyrochronology relations. Systematic errors at the 30% level are permitted by current data, highlighting the need for empirical guidance. We identify two fundamental sources of uncertainty that limit the precision of rotation-based ages and quantify their impact. Stars are born with a range of rotation rates, which leads to an age range at fixed rotation period. We find that the inherent ambiguity from the initial conditions is important for all young stars, and remains large for old stars below 0.6 M ⊙. Latitudinal surface differential rotation also introduces a minimum uncertainty into rotation period measurements and, by extension, rotation-based ages. Both models and the data from binary star systems 61 Cyg and α Cen demonstrate that latitudinal differential rotation is the limiting factor for rotation-based age precision among old field stars, inducing uncertainties at the ~2 Gyr level. We also examine the relationship between variability amplitude, rotation period, and age. Existing ground-based surveys can detect field populations with ages as old as 1-2 Gyr, while space missions can detect stars as old as the Galactic disk. In comparison with other techniques for measuring the ages of lower main sequence stars, including geometric parallax and asteroseismology, rotation-based ages have the potential to be the most precise chronometer for 0.6-1.0 M ⊙ stars.

  4. Rotating Connection for Electrical Cables

    NASA Technical Reports Server (NTRS)

    Manges, D. R.

    1986-01-01

    Cable reel provides electrical connections between fixed structure and rotating one. Reel carries power and signal lines while allowing rotating structure to turn up to 360 degrees with respect to fixed structure. Reel replaces sliprings. Can be used to electrically connect arm of robot with body. Reel releases cable to rotating part as it turns and takes up cable as rotating part comes back to its starting position, without tangling, twisting, or kinking.

  5. Rotating black hole hair

    NASA Astrophysics Data System (ADS)

    Gregory, Ruth; Kubizňák, David; Wills, Danielle

    2013-06-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that such a system displays much richer phenomenology than its static Schwarzschild or Reissner-Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is conical with respect to a local co-rotating frame, not with respect to the static frame at infinity.

  6. Snakes and spin rotators

    SciTech Connect

    Lee, S.Y.

    1990-06-18

    The generalized snake configuration offers advantages of either shorter total snake length and smaller orbit displacement in the compact configuration or the multi-functions in the split configuration. We found that the compact configuration can save about 10% of the total length of a snake. On other hand, the spilt snake configuration can be used both as a snake and as a spin rotator for the helicity state. Using the orbit compensation dipoles, the spilt snake configuration can be located at any distance on both sides of the interaction point of a collider provided that there is no net dipole rotation between two halves of the snake. The generalized configuration is then applied to the partial snake excitation. Simple formula have been obtained to understand the behavior of the partial snake. Similar principle can also be applied to the spin rotators. We also estimate the possible snake imperfections are due to various construction errors of the dipole magnets. Accuracy of field error of better than 10{sup {minus}4} will be significant. 2 refs., 5 figs.

  7. Energy and rotation-dependent stereodynamics of reaction

    NASA Astrophysics Data System (ADS)

    Yong-Qing, Li; Yun-Fan, Yang; Yang, Yu; Yong-Jia, Zhang; Feng-Cai, Ma

    2016-02-01

    Quasi-classical trajectory calculations are performed to study the stereodynamics of the reaction based on the first excited state NH2(12A‧) potential energy surface reported by Li et al. [Li Y Q and Varandas A J C 2010 J. Phys. Chem. A 114 9644] for the first time. We observe the changes of differential cross-sections at different collision energies and different initial reagent rotational excitations. The influence of collision energy on the k-k‧ distribution can be attributed to a purely impulsive effect. Initial reagent rotational excitation transforms the reaction mechanism from insertion to abstraction. The effect of initial reagent rotational excitations on k-k‧ distribution can be explained by the rotational excitation enlarging the rotational rate of reagent NH in the entrance channel to reduce the probability of collision between incidence H atom and H atom of target molecular. We also investigate the changes of vector correlations and find that the rotational angular momentum vector j‧ of the product H2 is not only aligned, but also oriented along the y axis. The alignment parameter, the disposal of total angular momentum and the reaction mechanism are all analyzed carefully to explain the polarization behavior of the product rotational angular moment. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474141and 11274149), the Program for Liaoning Excellent Talents in University, China (Grant No. LJQ2015040), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China (Grant No. 2014-1685), and the Special Fund Based Research New Technology of Methanol Conversion and Coal Instead of Oil and the China Postdoctoral Science Foundation (Grant No. 2014M550158).

  8. Metalloproteases and rotator cuff disease.

    PubMed

    Del Buono, Angelo; Oliva, Francesco; Longo, Umile Giuseppe; Rodeo, Scott A; Orchard, John; Denaro, Vincenzo; Maffulli, Nicola

    2012-02-01

    The molecular changes occurring in rotator cuff tears are still unknown, but much attention has been paid to better understand the role of matrix metalloproteinases (MMP) in the development of tendinopathy. These are potent enzymes that, once activated, can completely degrade all components of the connective tissue, modify the extracellular matrix (ECM), and mediatethe development of painful tendinopathy and tendon rupture. To control the local activity of activated proteinases, the same cells produce tissue inhibitors of metalloproteinases (TIMP) that bind to the enzymes and prevent degradation. The balance between the activities of MMPs and TIMPs regulates tendon remodeling, whereas an imbalance produces a collagen dis-regulation and disturbances intendons. ADAMs (a disintegrin and metalloproteinase) are cell membrane-linked enzymes with proteolytic and cell signaling functions. ADAMTSs (ADAM with thrombospondin motifs) are secreted into the circulation, and constitute a heterogenous family of proteases with both anabolic and catabolic functions. Biologic modulation of endogenous MMP activity to basal levels may reduce pathologic tissue degradation and favorably influence healing after rotator cuff repair. Further studies are needed to better define the mechanism of action, and whether these new strategies are safe and effective in larger models.

  9. Extraction of quasi-straightforward-propagating photons from diffused light transmitting through a scattering medium by polarization modulation

    NASA Astrophysics Data System (ADS)

    Horinaka, Hiromichi; Hashimoto, Koji; Wada, Kenji; Cho, Yoshio; Osawa, Masahiko

    1995-07-01

    The utilization of light polarization is proposed to extract quasi-straightforward-propagating photons from diffused light transmitting through a scattering medium under continuously operating conditions. Removal of a floor level normally appearing on the dynamic range over which the extraction capability is maintained is demonstrated. By use of pulse-based observations this cw scheme of extraction of quasi-straightforward-propagating photons is directly shown to be equivalent to the use of a temporal gate in the pulse-based operation.

  10. Fatigue Damage Accumulation Under Quasi-Random Loading of Composite Airframe Elements

    NASA Astrophysics Data System (ADS)

    Strizhius, V.

    2016-09-01

    To perform engineering estimations of the fatigue life of quasi-randomly loaded layered composites, with geometric concentrators, representing the longitudinal elements of composite wing of a transport airplane, a special rule of fatigue damage accumulation is suggested. The main propositions of the method for calculating the fatigue life of these elements by using this rule are formulated. The examples of estimations presented show a good agreement between analytical results and experimental data. A number of important conclusions about the effect of different levels of cyclic loading and "GAG" cycles of different flight types of the quasi-random "TWIST" program on the total fatigue life are made.

  11. Mixing of a passive scalar by the instability of a differentially rotating axial pinch

    NASA Astrophysics Data System (ADS)

    Paredes, A.; Gellert, M.; Rüdiger, G.

    2016-04-01

    The mean-field diffusion of passive scalars such as lithium, beryllium or temperature dispersals due to the magnetic Tayler instability of a rotating axial pinch is considered. Our study is carried out within a Taylor-Couette setup for two rotation laws: solid-body quasi-Kepler rotation. The minimum magnetic Prandtl number used is 0.05, and the molecular Schmidt number Sc of the fluid varies between 0.1 and 2. An effective diffusivity coefficient for the mixing is numerically measured by the decay of a prescribed concentration peak located between both cylinder walls. We find that only models with Sc exceeding 0.1 basically provide finite instability-induced diffusivity values. We also find that for quasi-Kepler rotation at a magnetic Mach number Mm ≃ 2, the flow transits from the slow-rotation regime to the fast-rotation regime that is dominated by the Taylor-Proudman theorem. For fixed Reynolds number, the relation between the normalized turbulent diffusivity and the Schmidt number of the fluid is always linear so that also a linear relation between the instability-induced diffusivity and the molecular viscosity results, just in the sense proposed by Schatzman (1977, A&A, 573, 80). The numerical value of the coefficient in this relation reaches a maximum at Mm ≃ 2 and decreases for larger Mm, implying that only toroidal magnetic fields on the order of 1 kG can exist in the solar tachocline.

  12. Quasi-planktonic behavior of foraging top marine predators

    PubMed Central

    Della Penna, Alice; De Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; d’Ovidio, Francesco

    2015-01-01

    Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1–100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels. PMID:26666350

  13. Quasi-planktonic behavior of foraging top marine predators

    NASA Astrophysics Data System (ADS)

    Della Penna, Alice; de Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; D'Ovidio, Francesco

    2015-12-01

    Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.

  14. Quasi-planktonic behavior of foraging top marine predators.

    PubMed

    Della Penna, Alice; De Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; d'Ovidio, Francesco

    2015-12-15

    Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.

  15. Simulated bioprosthetic heart valve deformation under quasi-static loading.

    PubMed

    Sun, Wei; Abad, Ajay; Sacks, Michael S

    2005-11-01

    For more than 40 years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. In this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120 mm Hg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design.

  16. Asymmetric Hip Rotation in Professional Baseball Pitchers

    PubMed Central

    McCulloch, Patrick C.; Patel, Jayesh K.; Ramkumar, Prem N.; Noble, Philip C.; Lintner, David M.

    2014-01-01

    Background: There is a renewed interest in examining the association between hip range of motion and injury in athletes, and the data on baseball players are conflicting. Understanding whether asymmetrical hip rotation is a normal adaptation or a risk factor for injury will help therapists, trainers, and physicians develop rehabilitation programs to improve kinetic energy transfer and prevent injury. As our knowledge of hip pathology among baseball pitchers improves, establishing baselines for hip motion is critical in the further assessment of injury. Hypothesis: Because of the repetitive nature of throwing sports and the adaptive changes documented in the shoulder, elite baseball pitchers would have characteristic patterns of hip internal and external rotations on their dominant throwing side (stance) and their nondominant side (stride) in extension. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computer software was used to measure passive internal and external rotations on digital photographs of 111 professional baseball pitchers. Results: In right-handed pitchers, there was significantly more internal rotation in the stance hip than the stride hip (32.2° ± 8.2° vs 30.8° ± 8.4°; P = .0349) and significantly more external rotation in the stride hip than the stance hip (36.3° ± 7.7° vs 30.8° ± 9.7°; P < .0001). While the mean difference in external rotation was 4.7°, 32% of the subjects had a >10° increase in external rotation on the stride hip relative to the stance hip. This population was statistically different from the remaining group for older age (P = .0053), lower body mass index (P = .0379), and more years in professional baseball (P = .0328). In the smaller number of left-handed pitchers, side-to-side differences in hip rotation were found but were not statistically significant. Conclusion: Pitchers showed more internal rotation on their stance hip and more external rotation on their stride hip. Although the mean

  17. Structural tailoring of counter rotation propfans

    NASA Technical Reports Server (NTRS)

    Brown, Kenneth W.; Hopkins, D. A.

    1989-01-01

    The STAT program was designed for the optimization of single rotation, tractor propfan designs. New propfan designs, however, generally consist of two counter rotating propfan rotors. STAT is constructed to contain two levels of analysis. An interior loop, consisting of accurate, efficient approximate analyses, is used to perform the primary propfan optimization. Once an optimum design has been obtained, a series of refined analyses are conducted. These analyses, while too computer time expensive for the optimization loop, are of sufficient accuracy to validate the optimized design. Should the design prove to be unacceptable, provisions are made for recalibration of the approximate analyses, for subsequent reoptimization.

  18. Tiltmeter leveling mechanism

    DOEpatents

    Hunter, Steven L.; Boro, Carl O.; Farris, Alvis

    2002-01-01

    A tiltmeter device having a pair of orthogonally disposed tilt sensors that are levelable within an inner housing containing the sensors. An outer housing can be rotated to level at least one of the sensor pair while the inner housing can be rotated to level the other sensor of the pair. The sensors are typically rotated up to about plus or minus 100 degrees. The device is effective for measuring tilts in a wide range of angles of inclination of wells and can be employed to level a platform containing a third sensor.

  19. Rotating plug bearing and seal

    DOEpatents

    Wade, Elman E.

    1977-01-01

    A bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing.

  20. The rotation of the earth

    NASA Technical Reports Server (NTRS)

    Herring, Thomas A.

    1991-01-01

    Earth rotation studies are reviewed for the 1987-1990 time period. It is noted that the emphasis in these studies has shifted from improvements in the observational techniques to interpreting and gaining greater understanding of the variations of the earth rotations. There have been progressive improvements in the accuracy and the temporal resolution of earth rotation measurements.

  1. Doppler observations of solar rotation

    NASA Technical Reports Server (NTRS)

    Scherrer, P. H.

    1980-01-01

    Daily observations of the photospheric equatorial rotation rate using the Doppler effect mode at the Sanford Solar Observatory are presented. These observations show no variations in the rotation rate that exceed the observational error of about one percent. The average rotation rate is indistinguishable from that of sunspots and large scale magnetic field structures.

  2. Doppler observations of solar rotation

    NASA Technical Reports Server (NTRS)

    Scherrer, P. H.; Wilcox, J. M.

    1980-01-01

    Daily observations of the photospheric equatorial rotation rate using the Doppler effect are made at the Stanford Solar Observatory. These observations show no variations in the rotation rate that exceed the observational error of about 1%. The average rotation rate is indistinguishable from that of sunspots and large-scale magnetic field structures.

  3. On the Product of Rotations

    ERIC Educational Resources Information Center

    Trenkler, G.; Trenkler, D.

    2008-01-01

    Using the elementary tools of matrix theory, we show that the product of two rotations in the three-dimensional Euclidean space is a rotation again. For this purpose, three types of rotation matrices are identified which are of simple structure. One of them is the identity matrix, and each of the other two types can be uniquely characterized by…

  4. Effects of rotating flows on combustion and jet noise.

    NASA Technical Reports Server (NTRS)

    Schwartz, I. R.

    1972-01-01

    Experimental investigations of combustion in rotating (swirling) flow have shown that the mixing and combustion processes were accelerated, flame length and noise levels significantly decreased, and flame stability increased relative to that obtained without rotation. Unsteady burning accompanied by a pulsating flame, violent fluctuating jet, and intense noise present in straight flow burning were not present in rotating flow burning. Correlations between theory and experiment show good agreement. Such effects due to rotating flows could lead to suppressing jet noise, improving combustion, reducing pollution, and decreasing aircraft engine size. Quantitative analysis of the aero-acoustic relationship and noise source characteristics are needed.-

  5. Influence of pelvis rotation styles on baseball pitching mechanics.

    PubMed

    Wight, Jeff; Richards, James; Hall, Susan

    2004-01-01

    Efficient, sequential timing is essential for upper level pitching. Interestingly, pitchers vary considerably in timing related elements of pitching style including pelvis rotation, arm cocking, stride leg behaviour, and pitch delivery time. The purpose of this study was to determine whether relationships exist among these elements by examining the overall style of pitchers exhibiting different pelvis rotation patterns. Pitching styles were defined by pelvis orientation at the instant of stride foot contact. Pitchers demonstrating a pelvis orientation greater than 30 degrees were designated as 'early rotators', while pitchers demonstrating a pelvis orientation less than 30 degrees were designated as 'late rotators'. Kinematic and temporal differences were associated with the two styles. During the arm cocking phase, early rotators showed significantly greater shoulder external rotation at the instant of stride foot contact, earlier occurrence of maximum pelvis rotation angular velocity, and shorter time taken to complete the phase. However, by the instant of maximum shoulder external rotation, early and late rotators appeared remarkably similar as no significant difference occurred in pelvis and arm orientations. Therefore, it appears that early and late rotators used different methods to achieve similar results, including throwing velocity. Significant differences in throwing arm kinetics were also found for 10 of the 11 measures in the study. As the pelvis assumed a more open position at stride foot contact, maximum kinetic values were found to both decrease in magnitude and occur at an earlier time within the pitch.

  6. Differentially Rotating White Dwarfs I: Regimes of Internal Rotation

    NASA Astrophysics Data System (ADS)

    Ghosh, Pranab; Wheeler, J. Craig

    2017-01-01

    Most viable models of Type Ia supernovae (SNe Ia) require the thermonuclear explosion of a carbon/oxygen white dwarf that has evolved in a binary system. Rotation could be an important aspect of any model for SNe Ia, whether single or double degenerate, with the white dwarf mass at, below, or above the Chandrasekhar limit. Differential rotation is specifically invoked in attempts to account for the apparent excess mass in the super-Chandrasekhar events. Some earlier work has suggested that only uniform rotation is consistent with the expected mechanisms of angular momentum transport in white dwarfs, while others have found pronounced differential rotation. We show that if the baroclinic instability is active in degenerate matter and the effects of magnetic fields are neglected, both nearly uniform rotation and strongly differential rotation are possible. We classify rotation regimes in terms of the Richardson number, Ri. At small values of Ri ≤slant 0.1, we find both the low-viscosity Zahn regime with a nonmonotonic angular velocity profile and a new differential rotation regime for which the viscosity is high and scales linearly with the shear, σ. Employment of Kelvin–Helmholtz viscosity alone yields differential rotation. Large values of Ri ≫ 1 produce a regime of nearly uniform rotation for which the baroclinic viscosity is of intermediate value and scales as {σ }3. We discuss the gap in understanding of the behavior at intermediate values of Ri and how observations may constrain the rotation regimes attained by nature.

  7. Scaling Effects in Carbon/Epoxy Laminates Under Transverse Quasi-Static Loading

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.; Douglas, Michael J.; Estes, Eric E.

    1999-01-01

    Scaling effects were considered for 8, 16, 32, and 64 ply IM-7/8551-7 carbon/epoxy composites plates transversely loaded to the first significant load drop by means of both a quasi-static and an equivalent impact force. The resulting damage was examined by x-ray and photomicroscopy analysis. Load-deflection curves were generated for the quasi-static tests and the resulting indentation depth was measured. Results showed that the load-deflection data scaled well for most of the various thicknesses of plates. However, damage did not scale as well. No correlation could be found between dent depth and any of the other parameters measured in this study. The impact test results showed that significantly less damage was formed compared to the quasi- static results for a given maximum transverse load. The criticality of ply-level scaling (grouping plies) was also examined.

  8. Axisymmetric compressible flow in a rotating cylinder with axial convection

    NASA Astrophysics Data System (ADS)

    Ungarish, M.; Israeli, M.

    1985-05-01

    The steady compressible flow of an ideal gas in a rotating annulus with thermally conducting walls is considered for small Rossby number epsilon and Ekman number E and moderate rotational Mach numbers M. Attention is focused on nonlinear effects which show up when sigma and epsilon M-squared are not small (sigma = epsilon/H square root of E, H is the dimensionless height of the container). These effects are not properly predicted by the classical linear perturbation analysis, and are treated here by quasi-linear extensions. The extra work required by these extensions is only the numerical solution of one ordinary differential equation for the pressure. Numerical solutions of the full Navier-Stokes equations in the nonlinear range are presented, and the validity of the present approach is confirmed.

  9. Spacetime rotation-induced Landau quantization

    NASA Astrophysics Data System (ADS)

    Konno, Kohkichi; Takahashi, Rohta

    2012-03-01

    We investigate noninertial and gravitational effects on quantum states in electromagnetic fields and present the analytic solution for energy eigenstates for the Schrödinger equation including noninertial, gravitational, and electromagnetic effects. We find that in addition to the Landau quantization the rotation of spacetime itself leads to the additional quantization, and that the energy levels for an electron are different from those for a proton at the level of gravitational corrections.

  10. Rotating Rayleigh-Taylor instability

    NASA Astrophysics Data System (ADS)

    Scase, M. M.; Baldwin, K. A.; Hill, R. J. A.

    2017-02-01

    The effect of rotation upon the classical Rayleigh-Taylor instability is investigated. We consider a two-layer system with an axis of rotation that is perpendicular to the interface between the layers. In general, we find that a wave mode's growth rate may be reduced by rotation. We further show that in some cases, unstable axisymmetric wave modes may be stabilized by rotating the system above a critical rotation rate associated with the mode's wavelength, the Atwood number, and the flow's aspect ratio.

  11. On type B cyclogenesis in a quasi-geostrophic model

    NASA Astrophysics Data System (ADS)

    Grotjahn, Richard

    2005-01-01

    A quasi-geostrophic (QG) model is used to approximate some aspects of 'type B' cyclogenesis as described in an observational paper that appeared several decades earlier in this journal. Though often cited, that earlier work has some ambiguity that has propagated into subsequent analyses. The novel aspects examined here include allowing advective nonlinearity to distort and amplify structures that are quasi-coherent and nearly stable in a linear form of the model; also, separate upper and lower structures are localized in space. Cases are studied separately where the upper trough tracks across different low-level features: an enhanced baroclinic zone (stronger horizontal temperature gradient) or a region of augmented temperature. Growth by superposition of lower and upper features is excluded by experimental design. The dynamics are evaluated with the vertical motion equation, the QG vorticity equation, the QG perturbation energy equation, and 'potential-vorticity thinking'. Results are compared against 'control' cases having no additional low-level features. Nonlinearity is examined relative to a corresponding linear calculation and is generally positive. The results are perhaps richer than the seminal article might imply, because growth is enhanced not only when properties of the lower feature reinforce growth but also when the lower feature opposes decay of the upper feature. For example, growth is enhanced where low-level warm advection introduces rising warm air to oppose the rising cold air ahead of the upper trough. Such growth is magnified when adjacent warm and cold anomalies have a strong baroclinic zone between them. The enhanced growth triggers an upstream tilt in the solution whose properties further accelerate the growth.

  12. Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

    NASA Astrophysics Data System (ADS)

    Kleiss, Ronald; Lazopoulos, Achilleas

    2006-07-01

    While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the absence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.

  13. Regimes of Internal Rotation in Differentially Rotating White Dwarfs

    NASA Astrophysics Data System (ADS)

    Wheeler, J. Craig; Ghosh, Pranab

    2017-01-01

    Most viable models of Type Ia supernovae (SN Ia) require the thermonuclear explosion of a carbon/oxygen white dwarf that has evolved in a binary system. Rotation could be an important aspect of any model for SN Ia, whether single or double degenerate, with the white dwarf mass at, below, or above the Chandrasekhar limit. Differential rotation is specifically invoked in attempts to account for the apparent excess mass in the super--Chandrasekhar events. Some earlier work has suggested that only uniform rotation is consistent with the expected mechanisms of angular momentum transport in white dwarfs, while others have found pronounced differential rotation. We show that if the baroclinic instability is active in degenerate matter and the effects of magnetic fields are neglected, both nearly-uniform and strongly-differential rotation are possible. We classify rotation regimes in terms of the Richardson number, Ri. At small values of Ri < 0.1, we find both the low-viscosity Zahn regime with a non-monotonic angular velocity profile and a new differential rotation regime for which the viscosity is high and scales linearly with the shear, σ. Employment of Kelvin-Helmholtz viscosity alone yields differential rotation. Large values of Ri >> 1 produce a regime of nearly-uniform rotation for which the baroclinic viscosity is of intermediate value and scales as σ3. We discuss the gap in understanding of the behavior at intermediate values of Ri and how observations may constrain the rotation regimes attained by nature.

  14. ROTATING PLASMA DEVICE

    DOEpatents

    Boyer, K.; Hammel, J.E.; Longmire, C.L.; Nagle, D.E.; Ribe, F.L.; Tuck, J.L.

    1961-10-24

    ABS>A method and device are described for obtaining fusion reactions. The basic concept is that of using crossed electric and magnetic fields to induce a plasma rotation in which the ionized particles follow a circumferential drift orbit on wldch a cyclotron mode of motion is superimposed, the net result being a cycloidal motion about the axis of symmetry. The discharge tube has a radial electric field and a longitudinal magnetic field. Mirror machine geometry is utilized. The device avoids reliance on the pinch effect and its associated instability problems. (AEC)

  15. Rotational isomerism of vinylmethyltelluride

    SciTech Connect

    Keiko, V.V.; Sinegovskaya, L.M.; Gusarova, N.K.; Tatarinova, A.A.; Kalinina, N.A.; Trofimov, B.A.

    1987-08-10

    In the IR spectrum of solutions of vinylmethyltelluride in n-heptane the doublet form of the valence oscillation band of the double bond is due to rotational isomerism. By analyzing the temperature dependence of the doublet shape, the low-frequency component of the doublet was identified as the s-cis-rotamer. The differences in the enthalpies (4.6 +/- 0.2 kJ/mole) and entropies (-11.1 +/- 0.3 e.u.) of the vinylmethyltelluride rotamers have been calculated and it has been shown that the p,..pi..-conjugation in its molecule is weaker by a factor of 2 than in vinylmethylsulfide.

  16. Quasi-thermal comptonization and GRBs

    NASA Astrophysics Data System (ADS)

    Ghisellini, G.; Celotti, A.

    1999-09-01

    Quasi-thermal Comptonization in internal shocks formed between relativistic shells can account for the high energy emission of gamma-ray bursts (GRB). This is the dominant cooling mechanism if the typical energy of the emitting particles is achieved either through the balance between heating and cooling or as a result of electron-positron (e(+/-) ) pair production. Both processes yield sub/mildly relativistic energies. In this case the synchrotron spectrum is self-absorbed, providing the seed photons for the Comptonization process, whose spectrum is flat [F(nu ) ~ const], ending either in an exponential cutoff or a Wien peak.

  17. Comparison of quasi-static and dynamic squats: a three-dimensional kinematic, kinetic and electromyographic study of the lower limbs.

    PubMed

    Clément, Julien; Hagemeister, Nicola; Aissaoui, Rachid; de Guise, Jacques A

    2014-01-01

    Numerous studies have described 3D kinematics, 3D kinetics and electromyography (EMG) of the lower limbs during quasi-static or dynamic squatting activities. One study compared these two squatting conditions but only at low speed on healthy subjects, and provided no information on kinetics and EMG of the lower limbs. The purpose of the present study was to contrast simultaneous recordings of 3D kinematics, 3D kinetics and EMG of the lower limbs during quasi-stat ic and fast-dynamic squats in healthy and pathological subjects. Ten subjects were recruited: five healthy and five osteoarthritis subjects. A motion-capture system, force plate, and surface electrodes respectively recorded 3D kinematics, 3D kinetics and EMG of the lower limbs. Each subject performed a quasi-static squat and several fast-dynamic squats from 0° to 70° of knee flexion. The two squatting conditions were compared for positions where quasi-static and fast-dynamic knee flexion-extension angles were similar. Mean differences between quasi-static and fast-dynamic squats were 1.5° for rotations, 1.9 mm for translations, 2.1% of subjects' body weight for ground reaction forces, 6.6 Nm for torques, 11.2 mm for center of pressure, and 6.3% of maximum fast-dynamic electromyographic activities for EMG. Some significant differences (p<0.05) were found in internal rotation, anterior translation, vertical force and EMG. All differences between quasi-static and fast-dynamic squats were small. 69.5% of compared data were equivalent. In conclusion, this study showed that quasi-static and fast-dynamic squatting activities are comparable in terms of 3D kinematics, 3D kinetics and EMG, although some reservations still remain.

  18. Pool boiling from rotating and stationary spheres in liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Cuan, Winston M.; Schwartz, Sidney H.

    1988-01-01

    Results are presented for a preliminary experiment involving saturated pool boiling at 1 atm from rotating 2 and 3 in. diameter spheres which were immersed in liquid nitrogen (LN2). Additional results are presented for a stationary, 2 inch diameter sphere, quenched in LN2, which were obtained utilizing a more versatile and complete experimental apparatus that will eventually be used for additional rotating sphere experiments. The speed for the rotational tests was varied from 0 to 10,000 rpm. The stationary experiments parametrically varied pressure and subcooling levels from 0 to 600 psig and from 0 to 50 F, respectively. During the rotational tests, a high speed photographic analysis was undertaken to measure the thickness of the vapor film surrounding the sphere. The average Nusselt number over the cooling period was plotted against the rotational Reynolds number. Stationary sphere results included local boiling heat transfer coefficients at different latitudinal locations, for various pressure and subcooling levels.

  19. Searching for Faraday rotation in cosmic microwave background polarization

    NASA Astrophysics Data System (ADS)

    Ruiz-Granados, B.; Battaner, E.; Florido, E.

    2016-08-01

    We use the Wilkinson Microwave Anisotropy Probe (WMAP) 9th-year foreground reduced data at 33, 41 and 61 GHz to derive a Faraday rotation at map and at angular power spectrum levels taking into account their observational errors. A processing mask provided by WMAP is used to avoid contamination from the disc of our Galaxy and local spurs. We have found a Faraday rotation component at both, map and power spectrum levels. The lack of correlation of the Faraday rotation with Galactic Faraday rotation, synchrotron and dust polarization from our Galaxy or with cosmic microwave background anisotropies or lensing suggests that it could be originated at reionization (ℓ ≲ 12). Even if the detected Faraday rotation signal is weak, the present study could contribute to establish magnetic fields strengths of B0 ˜ 10-8 G at reionization.

  20. Mesoporous nitrogen-doped TiO2 sphere applied for quasi-solid-state dye-sensitized solar cell.

    PubMed

    Xiang, Peng; Li, Xiong; Wang, Heng; Liu, Guanghui; Shu, Ting; Zhou, Ziming; Ku, Zhiliang; Rong, Yaoguang; Xu, Mi; Liu, Linfeng; Hu, Min; Yang, Ying; Chen, Wei; Liu, Tongfa; Zhang, Meili; Han, Hongwei

    2011-11-24

    A mesoscopic nitrogen-doped TiO2 sphere has been developed for a quasi-solid-state dye-sensitized solar cell [DSSC]. Compared with the undoped TiO2 sphere, the quasi-solid-state DSSC based on the nitrogen-doped TiO2 sphere shows more excellent photovoltaic performance. The photoelectrochemistry of electrodes based on nitrogen-doped and undoped TiO2 spheres was characterized with Mott-Schottky analysis, intensity modulated photocurrent spectroscopy, and electrochemical impedance spectroscopy, which indicated that both the quasi-Fermi level and the charge transport of the photoelectrode were improved after being doped with nitrogen. As a result, a photoelectric conversion efficiency of 6.01% was obtained for the quasi-solid-state DSSC.

  1. Numerical Study of Rotating Turbulence with External Forcing

    NASA Technical Reports Server (NTRS)

    Yeung, P. K.; Zhou, Ye

    1998-01-01

    Direct numerical simulation at 256(exp 3) resolution have been carried out to study the response of isotropic turbulence to the concurrent effects of solid-body rotation and numerical forcing at the large scales. Because energy transfer to the smaller scales is weakened by rotation, energy input from forcing gradually builds up at the large scales, causing the overall kinetic energy to increase. At intermediate wavenumbers the energy spectrum undergoes a transition from a limited k(exp -5/3) inertial range to k(exp -2) scaling recently predicted in the literature. Although the Reynolds stress tensor remains approximately isotropic and three-components, evidence for anisotropy and quasi- two-dimensionality in length scales and spectra in different velocity components and directions is strong. The small scales are found to deviate from local isotropy, primarily as a result of anisotropic transfer to the high wavenumbers. To understand the spectral dynamics of this flow we study the detailed behavior of nonlinear triadic interactions in wavenumber space. Spectral transfer in the velocity component parallel to the axis of rotation is qualitatively similar to that in non-rotating turbulence; however the perpendicular component is characterized by a greatly suppressed energy cascade at high wavenumber and a local reverse transfer at the largest scales. The broader implications of this work are briefly addressed.

  2. Quasi-biennial oscillation of the tropical stratospheric aerosol layer

    NASA Astrophysics Data System (ADS)

    Hommel, R.; Timmreck, C.; Giorgetta, M. A.; Graf, H. F.

    2015-05-01

    This study describes how aerosol in an aerosol-coupled climate model of the middle atmosphere is influenced by the quasi-biennial oscillation (QBO) during times when the stratosphere is largely unperturbed by volcanic material. In accordance with satellite observations, the vertical extent of the stratospheric aerosol layer in the tropics is modulated by the QBO by up to 6 km, or ~ 35% of its mean vertical extent between 100-7 hPa (about 16-33 km). Its largest vertical extent lags behind the occurrence of strongest QBO westerlies. The largest reduction lags behind maximum QBO easterlies. Strongest QBO signals in the aerosol surface area (30 %) and number densities (up to 100% e.g. in the Aitken mode) are found in regions where aerosol evaporates, that is above the 10 hPa pressure level (~ 31 km). Positive modulations are found in the QBO easterly shear, negative modulations in the westerly shear. Below 10 hPa, in regions where the aerosol mixing ratio is largest (50-20 hPa, or ~ 20-26 km), in most of the analysed parameters only moderate statistically significant QBO signatures (< 10%) have been found. QBO signatures in the model prognostic aerosol mixing ratio are significant at the 95% confidence level throughout the tropical stratosphere where modelled mixing ratios exceed 0.1 ppbm. In some regions of the tropical lower stratosphere the QBO signatures in other analysed parameters are partly not statistically significant. Peak-to-peak amplitudes of the QBO signature in the prognostic mixing ratios are up to twice as large as seasonal variations in the region where aerosols evaporate and between 70-30 hPa. Between the tropical tropopause and 70 hPa the QBO signature is relatively weak and seasonal variations dominate the variability of the simulated Junge layer. QBO effects on the upper lid of the tropical aerosol layer turn the quasi-static balance between processes maintaining the layer's vertical extent into a cyclic balance when considering this dominant mode

  3. Quasi-adiabatic compression heating of selected foods

    NASA Astrophysics Data System (ADS)

    Landfeld, Ales; Strohalm, Jan; Halama, Radek; Houska, Milan

    2011-03-01

    The quasi-adiabatic temperature increase due to compression heating, during high-pressure (HP) processing (HPP), was studied using specially designed equipment. The temperature increase was evaluated as the difference in temperature, during compression, between atmospheric pressure and nominal pressure. The temperature was measured using a thermocouple in the center of a polyoxymethylene cup, which contained the sample. Fresh meat balls, pork meat pate, and tomato purée temperature increases were measured at three initial temperature levels between 40 and 80 °C. Nominal pressure was either 400 or 500 MPa. Results showed that the fat content had a positive effect on temperature increases. Empirical equations were developed to calculate the temperature increase during HPP at different initial temperatures for pressures of 400 and 500 MPa. This thermal effect data can be used for numerical modeling of temperature histories of foods during HP-assisted pasteurization or sterilization processes.

  4. Superattraction mediated by quantum fluctuations of plasmon quasi-continuum.

    PubMed

    Andrianov, E S; Chtchelkatchev, N M; Pukhov, A A

    2015-05-01

    We investigate the force between a plasmonic nanoparticle and a highly excited two-level system (molecule). Usually van der Waals' force between nanoscale electrically neutral systems is monotonic and attractive at moderate and larger distances and repulsive at small distances. In our system, the van der Waals' force acting on a molecule has a quantum-optical nature. At moderate distances it is attractive as usual but its strength highly increases in narrow distance ranges (lacunas). We show that quantum fluctuations of quasi-continuum of multipole plasmons of high, nearly infinite degree, altogether form an effective environment and determine the interaction force while their spectral peculiarities stand behind the large and narrow lacunas in force. We exactly solve the Hamiltonian problem and discuss the role of the dissipation.

  5. Rotating drum filter

    DOEpatents

    Anson, Donald

    1990-01-01

    A perforated drum (10) rotates in a coaxial cylindrical housing (18) having three circumferential ports (19,22,23), and an axial outlet (24) at one end. The axis (11) is horizontal. A fibrous filter medium (20) is fed through a port (19) on or near the top of the housing (81) by a distributing mechanism (36) which lays a uniform mat (26) of the desired thickness onto the rotating drum (10). This mat (26) is carried by the drum (10) to a second port (23) through which dirty fluid (13) enters. The fluid (13) passes through the filter (26) and the cleaned stream (16) exits through the open end (15) of the drum (10) and the axial port (24) in the housing (18). The dirty filter material (20) is carried on to a third port (22) near the bottom of the housing (18) and drops into a receiver (31) from which it is continuously removed, cleaned (30), and returned (32) to the charging port (36) at the top. To support the filter mat, the perforated cylinder may carry a series of tines (40), shaped blades (41), or pockets, so that the mat (26) will not fall from the drum (10) prematurely. To minimize risk of mat failure, the fluid inlet port (23) may be located above the horizontal centerline (11).

  6. Optical rotation sensors

    NASA Astrophysics Data System (ADS)

    Rotge, J. R.; Simmons, B. J.; Kroncke, G. T.; Stech, D. J.

    1986-05-01

    Research efforts were concentrated on passive ring laser rotation sensor technology. Initial efforts were performed on supportive projects, e.g., laser stabilization, followed by a 0.62 sq m passive resonant ring laser gyro (PRRLG), leading to the development of a 60 sq m system mounted on the pneumatically supported isolation test platform (Iso-Pad) at FJSRL. Numerous sub-system tasks and a feasibility 0.62 sq m PRRLG were completed, supporting projections of very high resolution performance by a large 60 sq m PRRLG. The expected performance of the large PRRLG, on the order of 10 to the minus 10th power ERU (earth rate units), would provide an accurate error model applicable to Air Force operational ring laser gyros, a new source of geophysical data, e.g., earth wobble and variations in earth rotation, a proven design concept applicable to Air Force sensor needs as reference to MX instruments tests, and relativity experiments. This report documents the many accomplishments leading to, and the status of the large PRRLG at the date of the PRRLG stop order, November 1985.

  7. Digital rotation measurement unit

    DOEpatents

    Sanderson, S.N.

    1983-09-30

    A digital rotation indicator is disclosed for monitoring the position of a valve member having a movable actuator. The indicator utilizes mercury switches adapted to move in cooperation with the actuator. Each of the switches produces an output as it changes state when the actuator moves. A direction detection circuit is connected to the switches to produce a first digital signal indicative of the direction of rotation of the actuator. A count pulse generating circuit is also connected to the switches to produce a second digital pulse signal having count pulses corresponding to a change of state of any of the mercury switches. A reset pulse generating circuit is provided to generate a reset pulse each time a count pulse is generated. An up/down counter is connected to receive the first digital pulse signal and the second digital pulse signal and to count the pulses of the second digital pulse signal either up or down depending upon the instantaneous digital value of the first digital signal whereby a running count indicative of the movement of the actuator is maintained.

  8. Rotating Wheel Wake

    NASA Astrophysics Data System (ADS)

    Lombard, Jean-Eloi; Xu, Hui; Moxey, Dave; Sherwin, Spencer

    2016-11-01

    For open wheel race-cars, such as Formula One, or IndyCar, the wheels are responsible for 40 % of the total drag. For road cars, drag associated to the wheels and under-carriage can represent 20 - 60 % of total drag at highway cruise speeds. Experimental observations have reported two, three or more pairs of counter rotating vortices, the relative strength of which still remains an open question. The near wake of an unsteady rotating wheel. The numerical investigation by means of direct numerical simulation at ReD =400-1000 is presented here to further the understanding of bifurcations the flow undergoes as the Reynolds number is increased. Direct numerical simulation is performed using Nektar++, the results of which are compared to those of Pirozzoli et al. (2012). Both proper orthogonal decomposition and dynamic mode decomposition, as well as spectral analysis are leveraged to gain unprecedented insight into the bifurcations and subsequent topological differences of the wake as the Reynolds number is increased.

  9. Sample rotating turntable kit for infrared spectrometers

    DOEpatents

    Eckels, Joel Del; Klunder, Gregory L.

    2008-03-04

    An infrared spectrometer sample rotating turntable kit has a rotatable sample cup containing the sample. The infrared spectrometer has an infrared spectrometer probe for analyzing the sample and the rotatable sample cup is adapted to receive the infrared spectrometer probe. A reflectance standard is located in the rotatable sample cup. A sleeve is positioned proximate the sample cup and adapted to receive the probe. A rotator rotates the rotatable sample cup. A battery is connected to the rotator.

  10. Rotatable superconducting cyclotron adapted for medical use

    DOEpatents

    Blosser, Henry G.; Johnson, David A.; Riedel, Jack; Burleigh, Richard J.

    1985-01-01

    A superconducting cyclotron (10) rotatable on a support structure (11) in an arc of about 180.degree. around a pivot axis (A--A) and particularly adapted for medical use is described. The rotatable support structure (13, 15) is balanced by being counterweighted (14) so as to allow rotation of the cyclotron and a beam (12), such as a subparticle (neutron) or atomic particle beam, from the cyclotron in the arc around a patient. Flexible hose (25) is moveably attached to the support structure for providing a liquified gas which is supercooled to near 0.degree. K. to an inlet means (122) to a chamber (105) around superconducting coils (101, 102). The liquid (34) level in the cyclotron is maintained approximately half full so that rotation of the support structure and cyclotron through the 180.degree. can be accomplished without spilling the liquid from the cyclotron. With the coils vertically oriented, each turn of the winding is approximately half immersed in liquid (34) and half exposed to cold gas and adequate cooling to maintain superconducting temperatures in the section of coil above the liquid level is provided by the combination of cold gas/vapor and by the conductive flow of heat along each turn of the winding from the half above the liquid to the half below.

  11. Quasi-normal frequencies: key analytic results

    NASA Astrophysics Data System (ADS)

    Boonserm, Petarpa; Visser, Matt

    2011-03-01

    The study of exact quasi-normal modes [QNMs], and their associated quasi-normal frequencies [QNFs], has had a long and convoluted history — replete with many rediscoveries of previously known results. In this article we shall collect and survey a number of known analytic results, and develop several new analytic results — specifically we shall provide several new QNF results and estimates, in a form amenable for comparison with the extant literature. Apart from their intrinsic interest, these exact and approximate results serve as a backdrop and a consistency check on ongoing efforts to find general model-independent estimates for QNFs, and general model-independent bounds on transmission probabilities. Our calculations also provide yet another physics application of the Lambert W function. These ideas have relevance to fields as diverse as black hole physics, (where they are related to the damped oscillations of astrophysical black holes, to greybody factors for the Hawking radiation, and to more speculative state-counting models for the Bekenstein entropy), to quantum field theory (where they are related to Casimir energies in unbounded systems), through to condensed matter physics, (where one may literally be interested in an electron tunnelling through a physical barrier).

  12. Quasi-satellite system for leader-follower spacecraft formation

    NASA Astrophysics Data System (ADS)

    Harithuddin, A. S. M.

    2016-10-01

    The quasi-satellite motion is where a celestial body appears to orbit around another body that is also orbiting a common focus. The recent discoveries of asteroids in quasi-satellite motion around the Earth inspired this work. This paper attempts to look into exploiting the quasi-satellite dynamics in nature to provide a new perspective in spacecraft formation flight. We consider a two-spacecraft formation flight in which the follower appears to orbit of the leader in its reference frame. We perform a parametric analysis by varying the orbital elements of leader and follower examine the initial conditions needed to simulate a quasi-satellite formation system. We illustrate the trajectories of the follower spacecraft. This serves two purposes: firstly, to demonstrate formation flight based on the idea of quasi-satellite; and secondly, to gain some insights on the shapes of the resultant “quasi-orbits”.

  13. Compensations for increased rotational inertia during human cutting turns

    PubMed Central

    Qiao, Mu; Brown, Brian; Jindrich, Devin L.

    2014-01-01

    Locomotion in a complex environment is often not steady state, but unsteady locomotion (stability and maneuverability) is not well understood. We investigated the strategies used by humans to perform sidestep cutting turns when running. Previous studies have argued that because humans have small yaw rotational moments of inertia relative to body mass, deceleratory forces in the initial velocity direction that occur during the turning step, or ‘braking’ forces, could function to prevent body over-rotation during turns. We tested this hypothesis by increasing body rotational inertia and testing whether braking forces during stance decreased. We recorded ground reaction force and body kinematics from seven participants performing 45 deg sidestep cutting turns and straight running at five levels of body rotational inertia, with increases up to fourfold. Contrary to our prediction, braking forces remained consistent at different rotational inertias, facilitated by anticipatory changes to body rotational speed. Increasing inertia revealed that the opposing effects of several turning parameters, including rotation due to symmetrical anterior–posterior forces, result in a system that can compensate for fourfold changes in rotational inertia with less than 50% changes to rotational velocity. These results suggest that in submaximal effort turning, legged systems may be robust to changes in morphological parameters, and that compensations can involve relatively minor adjustments between steps to change initial stance conditions. PMID:24115061

  14. Compensations for increased rotational inertia during human cutting turns.

    PubMed

    Qiao, Mu; Brown, Brian; Jindrich, Devin L

    2014-02-01

    Locomotion in a complex environment is often not steady state, but unsteady locomotion (stability and maneuverability) is not well understood. We investigated the strategies used by humans to perform sidestep cutting turns when running. Previous studies have argued that because humans have small yaw rotational moments of inertia relative to body mass, deceleratory forces in the initial velocity direction that occur during the turning step, or 'braking' forces, could function to prevent body over-rotation during turns. We tested this hypothesis by increasing body rotational inertia and testing whether braking forces during stance decreased. We recorded ground reaction force and body kinematics from seven participants performing 45 deg sidestep cutting turns and straight running at five levels of body rotational inertia, with increases up to fourfold. Contrary to our prediction, braking forces remained consistent at different rotational inertias, facilitated by anticipatory changes to body rotational speed. Increasing inertia revealed that the opposing effects of several turning parameters, including rotation due to symmetrical anterior-posterior forces, result in a system that can compensate for fourfold changes in rotational inertia with less than 50% changes to rotational velocity. These results suggest that in submaximal effort turning, legged systems may be robust to changes in morphological parameters, and that compensations can involve relatively minor adjustments between steps to change initial stance conditions.

  15. Bifurcations of rotating waves in rotating spherical shell convection.

    PubMed

    Feudel, F; Tuckerman, L S; Gellert, M; Seehafer, N

    2015-11-01

    The dynamics and bifurcations of convective waves in rotating and buoyancy-driven spherical Rayleigh-Bénard convection are investigated numerically. The solution branches that arise as rotating waves (RWs) are traced by means of path-following methods, by varying the Rayleigh number as a control parameter for different rotation rates. The dependence of the azimuthal drift frequency of the RWs on the Ekman and Rayleigh numbers is determined and discussed. The influence of the rotation rate on the generation and stability of secondary branches is demonstrated. Multistability is typical in the parameter range considered.

  16. Cylindrical Cardboard Model for a Rotating System in Special Relativity.

    ERIC Educational Resources Information Center

    Noerdlinger, Peter D.

    1979-01-01

    Presents a cylindrical cardboard model that helps students at the graduate or undergraduate level to visualize the nature of simultaneity and the propagation of light in a rotating coordinate system. (HM)

  17. E(k)∝ k-5 observed at large k for rapidly rotating turbulent flow*

    NASA Astrophysics Data System (ADS)

    Swinney, Harry L.; Jung, Sungwhan; Yarbrough, Ray

    2004-11-01

    We have made velocity measurements on a quasi-two-dimensional turbulent flow in a rapidly rotating annulus (Reynolds number 20000, Rossby number 0.03). Earlier measurements demonstrated that in the inverse cascade (low wavenumbers), the energy scaling is given by E(k)∝ k-2 rather than the expected E(k)∝ k-5/3 [1]. Extending the measurements to high wavenumbers (into the forward enstrophy cascade), we find E(k)∝ k-5 rather than the E(k)∝ k-3 that has been found for a non-rotating quasi-two-dimensional flow [2]. Our observed value of -5 for the exponent is the same as a recently predicted bound for the exponent [3]. *Supported by ONR [1] C. N. Baroud et al., Phys. Rev. Lett. 88, 114501 (2002). [2] J. Paret and P. Tabeling, Phys. Fluids 10, 3126 (1998). [3] C. V. Tran and J. Bowman, Phys. Rev. E 69, 036303 (2004).

  18. A quasi-linear control theory analysis of timesharing skills

    NASA Technical Reports Server (NTRS)

    Agarwal, G. C.; Gottlieb, G. L.

    1977-01-01

    The compliance of the human ankle joint is measured by applying 0 to 50 Hz band-limited gaussian random torques to the foot of a seated human subject. These torques rotate the foot in a plantar-dorsal direction about a horizontal axis at a medial moleolus of the ankle. The applied torques and the resulting angular rotation of the foot are measured, digitized and recorded for off-line processing. Using such a best-fit, second-order model, the effective moment of inertia of the ankle joint, the angular viscosity and the stiffness are calculated. The ankle joint stiffness is shown to be a linear function of the level of tonic muscle contraction, increasing at a rate of 20 to 40 Nm/rad/Kg.m. of active torque. In terms of the muscle physiology, the more muscle fibers that are active, the greater the muscle stiffness. Joint viscosity also increases with activation. Joint stiffness is also a linear function of the joint angle, increasing at a rate of about 0.7 to 1.1 Nm/rad/deg from plantar flexion to dorsiflexion rotation.

  19. Parameterization of Natural Modes of Composite Rotating Conical Shells with Multiple Delamination

    NASA Astrophysics Data System (ADS)

    Dey, Sudip; Karmakar, Amit

    2012-01-01

    This paper describes a comparative study on free vibration of bending stiff, torsion stiff and quasi-isotropic graphite-epoxy composite conical shells with single and multiple delamination. The finite element formulation is based on Mindlin's theory and multi-point constraint algorithm neglecting the Coriolis effect for moderate rotational speeds. Computer codes are developed employing QR iteration method to obtain delaminated natural frequencies under combined effect of twist and rotation. Mode shapes are depicted for a typical laminate configuration. The non-dimensional natural frequencies obtained are the first known results which could serve as reference solutions for future investigators.

  20. Rotating Space Elevator: Classical and Statistical Mechanics of cosmic scale spinning strings

    NASA Astrophysics Data System (ADS)

    Knudsen, Steven; Golubovic, Leonardo

    2009-03-01

    We introduce a novel and unique nonlinear dynamical system, the Rotating Space Elevator (RSE). The RSE is a multiply rotating system of cables (strings) reaching beyond the Earth geo-synchronous satellite orbit. Strikingly, objects sliding along the RSE cable do not require internal engines or propulsion to be transported far away from the Earth's surface. The RSE action employs, in a very fundamental way, basic natural phenomena -- gravitation and inertial forces. The RSE exhibits interesting nonlinear dynamics and statistical physics phenomena. Its kinetic phase diagram involves both chaotic and quasi-periodic states of motion separated by a morphological phase transition that occurs with changing the RSE angular frequency.

  1. Mode- and plasma rotation in a resistive shell reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Malmberg, J.-A.; Brzozowski, J.; Brunsell, P. R.; Cecconello, M.; Drake, J. R.

    2004-02-01

    Mode rotation studies in a resistive shell reversed-field pinch, EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Control. Fusion 43, 1 (2001)] are presented. The phase relations and nonlinear coupling of the resonant modes are characterized and compared with that expected from modeling based on the hypothesis that mode dynamics can be described by a quasi stationary force balance including electromagnetic and viscous forces. Both m=0 and m=1 resonant modes are studied. The m=1 modes have rotation velocities corresponding to the plasma flow velocity (20-60 km/s) in the core region. The rotation velocity decreases towards the end of the discharge, although the plasma flow velocity does not decrease. A rotating phase locked m=1 structure is observed with a velocity of about 60 km/s. The m=0 modes accelerate throughout the discharges and reach velocities as high as 150-250 km/s. The observed m=0 phase locking is consistent with theory for certain conditions, but there are several conditions when the dynamics are not described. This is not unexpected because the assumption of quasi stationarity for the mode spectra is not fulfilled for many conditions. Localized m=0 perturbations are formed in correlation with highly transient discrete dynamo events. These perturbations form at the location of the m=1 phase locked structure, but rotate with a different velocity as they spread out in the toroidal direction.

  2. A Method for Achieving Constant Rotation Rates in a Micro-Orthogonal Linkage System

    SciTech Connect

    Dickey, F.M.; Holswade, S.C.; Romero, L.A.

    1999-05-12

    Silicon micromachine designs include engines that consist of orthog- onally oriented linear comb drive actuators mechanically connected to a rotating gear. These gears are as small as 50 {micro}m in diameter and can be driven at rotation rates exceeding 300,000 rpm. Generally, these en- gines will run with non-uniform rotation rates if the drive signals are not properly designed and maintained over a range of system parameters. We present a method for producing constant rotation rates in a micro-engine driven by an orthogonal linkage system. We show that provided the val- ues of certain masses, springs, damping factors, and lever arms are in the right proportions, the system behaves as though it were symmetrical. We will refer to systems built in this way as being quasi-symmetrical. We show that if a system is built quasi-symmetrically , then it is possible to achieve constant rotation rates even if one does not know the form of the friction function, or the value of the friction. We analyze this case in some detail.

  3. Quasi-Nambu-Goldstone Modes in Bose-Einstein Condensates

    SciTech Connect

    Uchino, Shun; Kobayashi, Michikazu; Nitta, Muneto; Ueda, Masahito

    2010-12-03

    We show that quasi-Nambu-Goldstone (NG) modes, which play prominent roles in high energy physics but have been elusive experimentally, can be realized with atomic Bose-Einstein condensates. The quasi-NG modes emerge when the symmetry of a ground state is larger than that of the Hamiltonian. When they appear, the conventional vacuum manifold should be enlarged. Consequently, topological defects that are stable within the conventional vacuum manifold become unstable and decay by emitting the quasi-NG modes. Contrary to conventional wisdom, however, we show that the topological defects are stabilized by quantum fluctuations that make the quasi-NG modes massive, thereby suppressing their emission.

  4. Rotational scanning atomic force microscopy.

    PubMed

    Ulčinas, A; Vaitekonis, Š

    2017-03-10

    A non-raster scanning technique for atomic force microscopy (AFM) imaging which combines rotational and translational motion is presented. The use of rotational motion for the fast scan axis allows us to significantly increase the scanning speed while imaging a large area (diameter > 30 μm). An image reconstruction algorithm and the factors influencing the resolution of the technique are discussed. The experimental results show the potential of the rotational scanning technique for high-throughput large area AFM investigation.

  5. Internal rotation of the sun

    NASA Technical Reports Server (NTRS)

    Duvall, T. L., Jr.; Dziembowski, W. A.; Goode, P. R.; Gough, D. O.; Harvey, J. W.; Leibacher, J. W.

    1984-01-01

    The frequency difference between prograde and retrograde sectoral solar oscillations is analyzed to determine the rotation rate of the solar interior, assuming no latitudinal dependence. Much of the solar interior rotates slightly less rapidly than the surface, while the innermost part apparently rotates more rapidly. The resulting solar gravitational quadrupole moment is J2 = (1.7 + or - 0.4) x 10 to the -7th and provides a negligible contribution to current planetary tests of Einstein's theory of general relativity.

  6. Rotational scanning atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Ulčinas, A.; Vaitekonis, Š.

    2017-03-01

    A non-raster scanning technique for atomic force microscopy (AFM) imaging which combines rotational and translational motion is presented. The use of rotational motion for the fast scan axis allows us to significantly increase the scanning speed while imaging a large area (diameter > 30 μm). An image reconstruction algorithm and the factors influencing the resolution of the technique are discussed. The experimental results show the potential of the rotational scanning technique for high-throughput large area AFM investigation.

  7. Rotating Detonation Engine Operation (Preprint)

    DTIC Science & Technology

    2012-01-01

    MdotH2 = mass flow of hydrogen MdotAir = mass flow of air PCB = Piezoelectric Pressure Sensor PDE = Pulsed Detonation Engine RDE = Rotating ...and unsteady thrust output of PDEs . One of the new designs was the Rotating Detonation Engine (RDE). An RDE operates by exhausting an initial...AFRL-RZ-WP-TP-2012-0003 ROTATING DETONATION ENGINE OPERATION (PREPRINT) James A. Suchocki and Sheng-Tao John Yu The Ohio State

  8. Uniformly Rotating Single Substance Bodies

    NASA Astrophysics Data System (ADS)

    Leonard, Charles Michael Leo

    This dissertation explicitly and in detail solves the extended rotator problem in the uncharged relativistic classical cases of most physical interest. It shows that no plausible relativistic solutions exist in the literature of the extended rotator and that the point rotator solutions sometimes ballyhooed are not to be taken seriously. Explicit energy speedratio functions, angular momentum speedratio functions, Hamiltonian, Lagrangian, and other important characteristic functions of the state of uniform rotation of the extended body are detailed. This dissertation does not retreat to an 'analysis' of just the point rotator --which so many others have done and done incorrectly, or at best misleadingly, by hiding implausible assumptions in manifestly covariant formats. Assumptions in the model are not hidden but are brought out and analyzed as to their relevance for highlighting the core of the uniform rotation physics. Neither does the author hide any ignorance of the internal holding field for the rotator. Formulae for the characteristic Minimum Holding Field are explicitly given and their relativistic relevance is shown. The demonstration that such fields can be ignored in the energy and angular momentum expressions is completely detailed. The explicit Stress-Energy Tensor for the entire closed rotator system is given with all that entails as to the inescapability of the results from out of that mathematics. The generality of the finiteness of the extreme relativistic rotational limit is detailed and explained with its stark essential contrast to the infinite limit in the case of extreme relativistic translation of a body. The rotator is shown to possess a rich mathematical structure. Many elegant interconnection formulae are found as well as new Hamiltonian formulae --sometimes of considerable complexity. Exact rotator formulae as well as graphs, tables, and even interesting approximations are provided. New nonlinear differential equations are discovered and

  9. The rotation of Uranus

    NASA Technical Reports Server (NTRS)

    Goody, R. M.

    1981-01-01

    A historical review of the use of three independent techniques for measuring the rotational rate is presented. The approaches examined are: (1) using theoretical interior models together with observations of the oblateness and the gravitational moment; (2) studying periodic fluctuations in the brightness; and (3) spectrographically measuring the Doppler shifts (line tilts). Measurements of line tilts obtained using the Kitt Peak National Observation 4 meter telescope with a Cassegrain echelle to high obtain high spectral dispersion and large image are discussed and compared with results obtained by Muench and Hipplelein (1980) and by Hayes and Belton (1977). The possibility of using speckel imaging techniques to detect the motion of features across the disc in the 6091 methane band, and with more suitable image intensifiers, in the 7261 band is considered.

  10. PLT rotating pumped limiter

    SciTech Connect

    Cohen, S.A.; Budny, R.V.; Corso, V.; Boychuck, J.; Grisham, L.; Heifetz, D.; Hosea, J.; Luyber, S.; Loprest, P.; Manos, D.

    1984-07-01

    A limiter with a specially contoured front face and the ability to rotate during tokamak discharges has been installed in a PLT pump duct. These features have been selected to handle the unique particle removal and heat load requirements of ICRF heating and lower-hybrid current-drive experiments. The limiter has been conditioned and commissioned in an ion-beam test stand by irradiation with 1 MW power, 200 ms duration beams of 40 keV hydrogen ions. Operation in PLT during ohmic discharges has proven the ability of the limiter to reduce localized heating caused by energetic electron bombardment and to remove about 2% of the ions lost to the PLT walls and limiters.

  11. Asteroid Ida Rotation Sequence

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This montage of 14 images (the time order is right to left, bottom to top) shows Ida as it appeared in the field of view of Galileo's camera on August 28, 1993. Asteroid Ida rotates once every 4 hours, 39 minutes and clockwise when viewed from above the north pole; these images cover about one Ida 'day.' This sequence has been used to create a 3-D model that shows Ida to be almost croissant shaped. The earliest view (lower right) was taken from a range of 240,000 kilometers (150,000 miles), 5.4 hours before closest approach. The asteroid Ida draws its name from mythology, in which the Greek god Zeus was raised by the nymph Ida.

  12. The Rapidly Rotating Sun

    NASA Technical Reports Server (NTRS)

    Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l < 60. The observationally constrained kinetic energy is approximately a thousandth of the theoretical prediction, suggesting the prevalence of an intrinsically different paradigm of turbulence. A fundamental question arises: what mechanism of turbulence transports the heat ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

  13. Rotating Gravity Gradiometer Study

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1976-01-01

    The application of a Rotating Gravity Gradiometer (RGG) system on board a Lunar Polar Orbiter (LPO) for the measurement of the Lunar gravity field was investigated. A data collection simulation study shows that a gradiometer will give significantly better gravity data than a doppler tracking system for the altitudes under consideration for the LOP, that the present demonstrated sensitivity of the RGG is adequate for measurement of the Lunar gravity gradient field, and that a single RGG instrument will provide almost as much data for geophysical interpretation as an orthogonal three axis RGG system. An engineering study of the RGG sensor/LPO spacecraft interface characteristics shows that the RGG systems under consideration are compatible with the present models of the LPO spacecraft.

  14. Rotating gravity gradiometer study

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1982-01-01

    Two rotating gravity gradiometer (RGG) sensors, along with all the external electronics needed to operate them, and the fixtures and special test equipment needed to fill and align the bearings, were assembled in a laboratory, and inspected. The thermal noise threshold of the RGG can be lowered by replacing a damping resistor in the first stage electronics by an active artificial resistor that generates less random voltage noise per unit bandwidth than the Johnson noise from the resistor it replaces. The artificial resistor circuit consists of an operational amplifier, three resistors, and a small DC to DC floating power supply. These are small enough to be retrofitted to the present circuit boards inside the RGG rotor in place of the 3 Megohm resistor. Using the artificial resistor, the thermal noise of the RGG-2 sensor can be lowered from 0.3 Eotvos to 0.15 Eotvos for a 10 sec integration time.

  15. Rotation Curves of Galaxies

    NASA Astrophysics Data System (ADS)

    Kalnajs, Agris J.

    One can obtain a fairly good understanding of the relation between axially symmetric mass distributions and the rotation curves they produce without resorting to calculations. However it does require a break with tradition. The first step consists of replacing quantities such as surface density, volume density, and circular velocity with the mass in a ring, mass in a spherical shell, and the square of the circular velocity, or more precisely with 2 pi G r mu(r), 4 pi G r^2 rho(r), and Vc^2 (r). These three quantities all have the same dimensions, and are related to each other by scale-free linear operators. The second step consists of introducing ln(r) as the coordinate. On the log scale the scale-free operators becomes the more familiar convolution operations. Convolutions are easily handled by Fourier techniques and a surface density can be converted into a rotation curve or volume density in a small fraction of a second. A simple plot of 2 pi G r mu(r) as a function of ln(r) reveals the relative contributions of different radii to Vc^2(r). Such a plot also constitutes a sanity test for the fitting of various laws to photometric data. There are numerous examples in the literature of excellent fits to the tails that lack data or are poor fits around the maximum of 2 pi G r mu(r). I will discuss some exact relations between the above three quantities as well as some empirical observations such as the near equality of the maxima of 2 pi G r mu(r) and Vc^2 (r) curves for flat mass distributions.

  16. Plasma rotation induced by RF

    SciTech Connect

    Chan, V. S.; Chiu, S. C.; Lin-Liu, Y. R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5698; Omelchenko, Y. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5698

    1999-09-20

    Plasma rotation has many beneficial effects on tokamak operation including stabilization of MHD and microturbulence to improve the beta limit and confinement. Contrary to present-day tokamaks, neutral beams may not be effective in driving rotation in fusion reactors; hence the investigation of radiofrequency (RF) induced plasma rotation is of great interest and potential importance. This paper reviews the experimental results of RF induced rotation and possible physical mechanisms, suggested by theories, to explain the observations. This subject is only in the infancy of its research and many challenging issues remained to be understood and resolved. (c) 1999 American Institute of Physics.

  17. Longitudinal Variation of the Stratospheric Quasi-Biennial Oscillation.

    NASA Astrophysics Data System (ADS)

    Hamilton, Kevin; Hertzog, Albert; Vial, François; Stenchikov, Georgiy

    2004-02-01

    The longitudinal dependence of interannual variations of tropical stratospheric wind is examined in a detailed general circulation model simulation and in the limited observations available. A version of the SKYHI model is run with an imposed zonally symmetric zonal momentum source that forces the zonal-mean zonal wind evolution in the tropical stratosphere to be close to an estimate of the observed zonal wind based on radiosonde observations at Singapore during the period 1978 99. This amounts to a kind of simple assimilation model in which only the zonal-mean wind field in the tropical stratosphere is assimilated, and other quantities are allowed to vary freely. A total of five experiments were run, one covering the full 1978 99 period and four for 1989 99.The results at and above about 30 hPa are fairly simple to characterize. When the zonal-mean wind near the equator at a particular level is easterly, the monthly mean wind has only very small zonal contrasts. When mean westerlies are present near the equator, significant zonal asymmetries occur at low latitudes, most notably easterly anomalies over South America and westerly anomalies in the eastern Pacific region. These anomalies generally display a continuous meridional phase propagation with the extratropical quasi-stationary eddy field in the winter hemisphere. The net result is a significantly weaker peak-to-peak amplitude of the quasi-biennial oscillation (QBO) in zonal wind over the South American sector than over the rest of the equatorial band. The zonal contrast in QBO amplitude near 10 hPa exceeds 10%.In the lower stratosphere the zonal asymmetries in the prevailing wind are fairly small. Asymmetries seem to reflect the upward extension of the tropospheric Walker circulation, and are less strongly modulated by the quasi-biennial oscillation in zonal-mean circulation.The model results were checked against limited station observations at Nairobi (1.3°S, 36.7°E), Singapore (1.4°N, 103.9

  18. Image Rotation Does Not Rotate Smooth Eye Movements

    NASA Technical Reports Server (NTRS)

    Mulligan, Jeffrey B.; Stone, Leland S. (Technical Monitor)

    1997-01-01

    Subjects viewing a drifting noise pattern make reflexive smooth eye movements in the direction of motion, which follow rapid changes in movement direction. These responses are unaffected by rotations of the pattern, suggesting that there is no coupling between visually sensed rotation and the direction of ocular following.

  19. Modeling rigid magnetically rotated microswimmers: Rotation axes, bistability, and controllability

    NASA Astrophysics Data System (ADS)

    Meshkati, Farshad; Fu, Henry Chien

    2014-12-01

    Magnetically actuated microswimmers have recently attracted attention due to many possible biomedical applications. In this study we investigate the dynamics of rigid magnetically rotated microswimmers with permanent magnetic dipoles. Our approach uses a boundary element method to calculate a mobility matrix, accurate for arbitrary geometries, which is then used to identify the steady periodically rotating orbits in a co-rotating body-fixed frame. We evaluate the stability of each of these orbits. We map the magnetoviscous behavior as a function of dimensionless Mason number and as a function of the angle that the magnetic field makes with its rotation axis. We describe the wobbling motion of these swimmers by investigating how the rotation axis changes as a function of experimental parameters. We show that for a given magnetic field strength and rotation frequency, swimmers can have more than one stable periodic orbit with different rotation axes. Finally, we demonstrate that one can improve the controllability of these types of microswimmers by adjusting the relative angle between the magnetic field and its axis of rotation.

  20. Quasi-Experimental Study Designs Series- Paper 13: Realizing the Full Potential of Quasi-Experiments for Health Research.

    PubMed

    Rockers, Peter C; Tugwell, Peter; Røttingen, John-Arne; Bärnighausen, Till

    2017-04-05

    While the number of quasi-experiments conducted by health researchers has increased in recent years, there clearly remains unrealized potential for using these methods for causal evaluation of health policies and programs globally. This article proposes five prescriptions for capturing the full value of quasi-experiments for health research. First, new funding opportunities targeting proposals that use quasi-experimental methods should be made available to a broad pool of health researchers. Second, administrative data from health programs, often amenable to quasi-experimental analysis, should be made more accessible to researchers. Third, training in quasi-experimental methods should be integrated into existing health science graduate programs to increase global capacity to use these methods. Fourth, clear guidelines for primary research and synthesis of evidence from quasi-experiments should be developed. Fifth, strategic investments should be made to continue to develop new innovations in quasi-experimental methodologies. Tremendous opportunities exist to expand the use of quasi-experimental methods to increase our understanding of which health programs and policies work and which do not. Health researchers should continue to expand their commitment to rigorous causal evaluation with quasi-experimental methods, and international institutions should increase their support for these efforts.

  1. Surface dimpling on rotating work piece using rotation cutting tool

    DOEpatents

    Bhapkar, Rohit Arun; Larsen, Eric Richard

    2015-03-31

    A combined method of machining and applying a surface texture to a work piece and a tool assembly that is capable of machining and applying a surface texture to a work piece are disclosed. The disclosed method includes machining portions of an outer or inner surface of a work piece. The method also includes rotating the work piece in front of a rotating cutting tool and engaging the outer surface of the work piece with the rotating cutting tool to cut dimples in the outer surface of the work piece. The disclosed tool assembly includes a rotating cutting tool coupled to an end of a rotational machining device, such as a lathe. The same tool assembly can be used to both machine the work piece and apply a surface texture to the work piece without unloading the work piece from the tool assembly.

  2. Nonperturbative evolution of parton quasi-distributions

    NASA Astrophysics Data System (ADS)

    Radyushkin, A. V.

    2017-04-01

    Using the formalism of parton virtuality distribution functions (VDFs) we establish a connection between the transverse momentum dependent distributions (TMDs) F (x , k⊥2) and quasi-distributions (PQDs) Q (y ,p3) introduced recently by X. Ji for lattice QCD extraction of parton distributions f (x). We build models for PQDs from the VDF-based models for soft TMDs, and analyze the p3 dependence of the resulting PQDs. We observe a strong nonperturbative evolution of PQDs for small and moderately large values of p3 reflecting the transverse momentum dependence of TMDs. Thus, the study of PQDs on the lattice in the domain of strong nonperturbative effects opens a new perspective for investigation of the 3-dimensional hadron structure.

  3. On generalized quasi-convex bounded sequences

    NASA Astrophysics Data System (ADS)

    Karakuş, Mahmut

    2016-08-01

    The space of all sequences a = (ak) for which ‖a ‖q= ∑k k |Δ2ak | +supk|ak | <∞ is denoted by q. Here, Δak = ak - ak+1 and Δmak = Δ(Δm-1ak) = Δm-1ak - Δm-1ak+1 with Δ0ak = ak, m ≥ 1. If a = (ak) ∈q then kΔak → 0 (k → ∞) and q ⊂ bv, the space of all sequences of bounded-variation, since ∑k | Δ ak | ≤ ∑k k | Δ2ak | In this study, we give a generalization of quasi-convex bounded sequences.

  4. Quasi-Elastic Light Scattering in Ophthalmology

    NASA Astrophysics Data System (ADS)

    Ansari, Rafat R.

    The eye is not just a "window to the soul"; it can also be a "window to the human body." The eye is built like a camera. Light which travels from the cornea to the retina traverses through tissues that are representative of nearly every tissue type and fluid type in the human body. Therefore, it is possible to diagnose ocular and systemic diseases through the eye. Quasi-elastic light scattering (QELS) also known as dynamic light scattering (DLS) is a laboratory technique routinely used in the characterization of macromolecular dispersions. QELS instrumentation has now become more compact, sensitive, flexible, and easy to use. These developments have made QELS/DLS an important tool in ophthalmic research where disease can be detected early and noninvasively before the clinical symptoms appear.

  5. Quasi-elastic neutrino-nucleus reactions

    NASA Astrophysics Data System (ADS)

    Valverde, M.; Nieves, J.; Amaro, J. E.

    2006-05-01

    The quasi-elastic contribution of the nuclear inclusive electron scattering model developed in [A. Gil, J. Nieves, and E. Oset: Nucl. Phys. A 627 (1997) 543] is extended to the study of electroweak charged current induced nuclear reactions at intermediate energies of interest for future neutrino oscillation experiments. The model accounts for long-range nuclear (RPA) correlations, final state interaction and Coulomb corrections. RPA correlations are shown to play a crucial role in the whole range of neutrino energies, up to 500 MeV, studied in this work. Predictions for inclusive muon capture for different nuclei, and for the reactions 12C(ν μ , μ -)X and 12C(ν e, e-)X near threshold are also given.

  6. Optical localization in quasi-periodic multilayers

    NASA Astrophysics Data System (ADS)

    Vasconcelos, M. S.; Albuquerque, E. L.; Mariz, A. M.

    1998-07-01

    We investigate the optical transmission spectra of quasi-periodic dielectric multilayer slabs arranged in a fashion that exhibits what has been called deterministic disorders. They can be of the so-called substitutional sequences type, and are characterized by the nature of their Fourier spectrum, which can be dense pure point (e.g. a Fibonacci sequence) or singular continuous (e.g. Thue-Morse and double-period sequences). The transmission coefficients are conveniently derived by using a theoretical model based on the transfer-matrix approach. A comparison between the oblique-incidence optical transmission spectrum and the normal-incidence one shows quite a different transmission behaviours over a particular range of frequency.

  7. Forces acting in quasi 2d emulsions

    NASA Astrophysics Data System (ADS)

    Orellana, Carlos; Lowensohn, Janna; Weeks, Eric

    We study the forces in a quasi two dimensional emulsion system. Our samples are oil-in-water emulsions confined between two close-spaced parallel plates, so that the oil droplets are deformed into pancake shapes. By means of microscopy, we measure the droplet positions and their deformation, which we can relate to the contact forces due to surface tension. We improve over prior work in our lab, achieving a better force resolution. We use this result to measure and calibrate the viscous forces acting in our system, which fully determine all the forces on the droplets. Our results can be applied to study static configurations of emulsion, as well as faster flows.

  8. Rotational Spectroscopy of Methyl Vinyl Ketone

    NASA Astrophysics Data System (ADS)

    Zakharenko, Olena; Motiyenko, R. A.; Aviles Moreno, Juan-Ramon; Huet, T. R.

    2015-06-01

    Methyl vinyl ketone, MVK, along with previously studied by our team methacrolein, is a major oxidation product of isoprene, which is one of the primary contributors to annual global VOC emissions. In this talk we present the analysis of the rotational spectrum of MVK recorded at room temperature in the 50 -- 650 GHz region using the Lille spectrometer. The spectroscopic characterization of MVK ground state will be useful in the detailed analysis of high resolution infrared spectra. Our study is supported by high level quantum chemical calculations to model the structure of the two stable s-trans and s-cis conformers and to obtain the harmonic force field parameters, internal rotation barrier heights, and vibrational frequencies. In the Doppler-limited spectra the splittings due to the internal rotation of methyl group are resolved, therefore for analysis of this molecule we used the Rho-Axis-Method Hamiltonian and RAM36 code to fit the rotational transitions. At the present time the ground state of two conformers is analyzed. Also we intend to study some low lying excited states. The analysis is in progress and the latest results will be presented. Support from the French Laboratoire d'Excellence CaPPA (Chemical and Physical Properties of the Atmosphere) through contract ANR-10-LABX-0005 of the Programme d'Investissements d'Avenir is acknowledged.

  9. QUASI-BIENNIAL OSCILLATIONS IN THE SOLAR TACHOCLINE CAUSED BY MAGNETIC ROSSBY WAVE INSTABILITIES

    SciTech Connect

    Zaqarashvili, Teimuraz V.; Carbonell, Marc; Oliver, Ramon; Ballester, Jose Luis E-mail: marc.carbonell@uib.e E-mail: joseluis.ballester@uib.e

    2010-11-20

    Quasi-biennial oscillations (QBOs) are frequently observed in solar activity indices. However, no clear physical mechanism for the observed variations has been suggested so far. Here, we study the stability of magnetic Rossby waves in the solar tachocline using the shallow water magnetohydrodynamic approximation. Our analysis shows that the combination of typical differential rotation and a toroidal magnetic field with a strength of {>=}10{sup 5} G triggers the instability of the m = 1 magnetic Rossby wave harmonic with a period of {approx}2 years. This harmonic is antisymmetric with respect to the equator and its period (and growth rate) depends on the differential rotation parameters and magnetic field strength. The oscillations may cause a periodic magnetic flux emergence at the solar surface and consequently may lead to the observed QBO in solar activity features. The period of QBOs may change throughout a cycle, and from cycle to cycle, due to variations of the mean magnetic field and differential rotation in the tachocline.

  10. Rotational stiffness of football shoes influences talus motion during external rotation of the foot.

    PubMed

    Wei, Feng; Meyer, Eric G; Braman, Jerrod E; Powell, John W; Haut, Roger C

    2012-04-01

    Shoe-surface interface characteristics have been implicated in the high incidence of ankle injuries suffered by athletes. Yet, the differences in rotational stiffness among shoes may also influence injury risk. It was hypothesized that shoes with different rotational stiffness will generate different patterns of ankle ligament strain. Four football shoe designs were tested and compared in terms of rotational stiffness. Twelve (six pairs) male cadaveric lower extremity limbs were externally rotated 30 deg using two selected football shoe designs, i.e., a flexible shoe and a rigid shoe. Motion capture was performed to track the movement of the talus with a reflective marker array screwed into the bone. A computational ankle model was utilized to input talus motions for the estimation of ankle ligament strains. At 30 deg of rotation, the rigid shoe generated higher ankle joint torque at 46.2 ± 9.3 Nm than the flexible shoe at 35.4 ± 5.7 Nm. While talus rotation was greater in the rigid shoe (15.9 ± 1.6 deg versus 12.1 ± 1.0 deg), the flexible shoe generated more talus eversion (5.6 ± 1.5 deg versus 1.2± 0.8 deg). While these talus motions resulted in the same level of anterior deltoid ligament strain (approxiamtely 5%) between shoes, there was a significant increase of anterior tibiofibular ligament strain (4.5± 0.4% versus 2.3 ± 0.3%) for the flexible versus more rigid shoe design. The flexible shoe may provide less restraint to the subtalar and transverse tarsal joints, resulting in more eversion but less axial rotation of the talus during foot∕shoe rotation. The increase of strain in the anterior tibiofibular ligament may have been largely due to the increased level of talus eversion documented for the flexible shoe. There may be a direct correlation of ankle joint torque with axial talus rotation, and an inverse relationship between torque and talus eversion. The study may provide some insight into relationships between shoe

  11. Spatially homogeneous rotating world models.

    NASA Technical Reports Server (NTRS)

    Ozsvath, I.

    1971-01-01

    The mathematical problem encountered when looking for the simplest expanding and rotating model of the universe without the compactness condition for the space sections is formulated. The Lagrangian function is derived for four different rotating universes simultaneously. These models correspond in a certain sense to Godel's (1950) ?symmetric case.'

  12. Rotation of the planet mercury.

    PubMed

    Jefferys, W H

    1966-04-08

    The equations of motion for the rotation of Mercury are solved for the general case by an asymptotic expansion. The findings of Liu and O'Keefe, obtained by numerical integration of a special case, that it is possible for Mercury's rotation to be locked into a 2:3 resonance with its revolution, are confirmed in detail. The general solution has further applications.

  13. Rotational joint for prosthetic leg

    NASA Technical Reports Server (NTRS)

    Jones, W. C.; Owens, L. J.

    1977-01-01

    Device is installed in standard 30 millimeter tubing used for lower leg prosthetics. Unit allows proper rotation (about 3 degrees) of foot relative to the hip, during normal walking or running. Limited rotational movement with restoring force results in a more natural gait.

  14. Quasi-resonant circulation regimes and hemispheric synchronization of extreme weather in boreal summer.

    PubMed

    Coumou, Dim; Petoukhov, Vladimir; Rahmstorf, Stefan; Petri, Stefan; Schellnhuber, Hans Joachim

    2014-08-26

    The recent decade has seen an exceptional number of high-impact summer extremes in the Northern Hemisphere midlatitudes. Many of these events were associated with anomalous jet stream circulation patterns characterized by persistent high-amplitude quasi-stationary Rossby waves. Two mechanisms have recently been proposed that could provoke such patterns: (i) a weakening of the zonal mean jets and (ii) an amplification of quasi-stationary waves by resonance between free and forced waves in midlatitude waveguides. Based upon spectral analysis of the midtroposphere wind field, we show that the persistent jet stream patterns were, in the first place, due to an amplification of quasi-stationary waves with zonal wave numbers 6-8. However, we also detect a weakening of the zonal mean jet during these events; thus both mechanisms appear to be important. Furthermore, we demonstrate that the anomalous circulation regimes lead to persistent surface weather conditions and therefore to midlatitude synchronization of extreme heat and rainfall events on monthly timescales. The recent cluster of resonance events has resulted in a statistically significant increase in the frequency of high-amplitude quasi-stationary waves of wave numbers 7 and 8 in July and August. We show that this is a robust finding that holds for different pressure levels and reanalysis products. We argue that recent rapid warming in the Arctic and associated changes in the zonal mean zonal wind have created favorable conditions for double jet formation in the extratropics, which promotes the development of resonant flow regimes.

  15. A combined photoelectron spectroscopy and ab initio study of the quasi-planar B24- cluster

    NASA Astrophysics Data System (ADS)

    Popov, Ivan A.; Piazza, Zachary A.; Li, Wei-Li; Wang, Lai-Sheng; Boldyrev, Alexander I.

    2013-10-01

    The structure and chemical bonding of the 24-atom boron cluster are investigated using photoelectron spectroscopy and ab initio calculations. The joint experimental and theoretical investigation shows that B24- possesses a quasi-planar structure containing fifteen outer and nine inner atoms with six of the inner atoms forming a filled pentagonal moiety. The central atom of the pentagonal moiety is puckered out of plane by 0.9 Å, reminiscent of the six-atom pentagonal caps of the well-known B12 icosahedral unit. The next closest isomer at the ROCCSD(T) level of theory has a tubular double-ring structure. Comparison of the simulated spectra with the experimental data shows that the global minimum quasi-planar B24- isomer is the major contributor to the observed photoelectron spectrum, while the tubular isomer has no contribution to the experiment. Chemical bonding analyses reveal that the periphery of the quasi-planar B24 constitutes 15 classical 2c-2e B-B σ-bonds, whereas delocalized σ- and π-bonds are found in the interior of the cluster with one unique 6c-2e π-bond responsible for bonding in the B-centered pentagon. The current work suggests that the 24-atom boron cluster continues to be quasi-2D, albeit the tendency to form filled pentagonal units, characteristic of 3D cage-like structures of bulk boron, is observed.

  16. A Planar Quasi-Static Constraint Mode Tire Model

    DTIC Science & Technology

    2015-07-10

    UNCLASSIFIED: Distribution Statement A. Cleared for public release A PLANAR QUASI- STATIC CONSTRAINT MODE TIRE MODEL Rui Maa John B. Ferris...demands efficiency in the simulation of suspension loads. Toward that end, a computationally efficient, linear, planar, quasi- static tire model is...bridging properties via component mode synthesis originated by Hurty and Gladwell and the Guyan static reduction method decouples active constraints

  17. E x B shearing rate in quasi-symmetric plasmas

    SciTech Connect

    Hahm, T.S.

    1997-06-20

    The suppression of turbulence by the E x B shear is studied in systems with quasi-symmetry using the nonlinear analysis of eddy decorrelation previously utilized in finite aspect ratio tokamak plasmas. The analytically derived E x B shearing rate which contains the relevant geometric dependence can be used for quantitative assessment of the fluctuation suppression in stellarators with quasi-symmetry.

  18. Asymptotic Spectra Of Banded Quasi-Toeplitz Matrices

    NASA Technical Reports Server (NTRS)

    Beam, Richard; Warming, Robert

    1995-01-01

    Paper presents theoretical and numerical study of asymptotic spectra of eigenvalues of banded Toeplitz and quasi-Toeplitz matrices. Emphasis in study on non-normal banded Toeplitz and quasi-Toeplitz matrices of arbitrarily large order and relatively small bandwidth.

  19. Segmented Polynomial Models in Quasi-Experimental Research.

    ERIC Educational Resources Information Center

    Wasik, John L.

    1981-01-01

    The use of segmented polynomial models is explained. Examples of design matrices of dummy variables are given for the least squares analyses of time series and discontinuity quasi-experimental research designs. Linear combinations of dummy variable vectors appear to provide tests of effects in the two quasi-experimental designs. (Author/BW)

  20. Study of transionospheric signal scintillation: Quasi- particle approach

    NASA Astrophysics Data System (ADS)

    Lyle, Ruthie D.

    1998-07-01

    A quasi-particle approach is applied to study amplitude scintillation of transionospheric signals caused by Bottomside Sinusoidal (BSS) irregularities. The quasi- particle method exploits wave-particle duality, viewing the wave as a distribution of quasi-particles. This is accomplished by transforming the autocorrelation of the wave function into a Wigner distribution function, which serves as a distribution of quasi-particles in the (/vec r,/ /vec k) phase space. The quasi-particle distribution at any instant of time represents the instantaneous state of the wave. Scattering of the signal by the ionospheric irregularities is equivalent to the evolution of the quasi-particle distribution, due to the collision of the quasi-particles with objects arising from the presence of the BSS irregularities. Subsequently, the perturbed quasi-particle distribution facilitates the computation of average space time propagation properties of the wave. Thus, the scintillation index S4 is determined. Incorporation of essential BSS features in the analysis is accomplished by analytically modeling the power spectrum of the BSS irregularities measured in-situ by the low orbiting Atmosphere-E (AE - E) Satellite. The effect of BSS irregularities on transionospheric signals has been studied. The numerical results agree well with multi-satellite scintillation observations made at Huancayo Peru in close time correspondence with BSS irregularities observed by the AE - E satellite over a few nights (December 8-11, 1979). During this period, the severity of the scintillation varied from moderate to intense, S4 = 0.1-0.8.

  1. Hidden algebra method (quasi-exact-solvability in quantum mechanics)

    SciTech Connect

    Turbiner, Alexander

    1996-02-20

    A general introduction to quasi-exactly-solvable problems of quantum mechanics is presented. Main attention is given to multidimensional quasi-exactly-solvable and exactly-solvable Schroedinger operators. Exact-solvability of the Calogero and Sutherland N-body problems ass ociated with an existence of the hidden algebra slN is discussed extensively.

  2. Quasi-biennial corn yield cycles in Iowa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quasi-biennial cycles are often reported in climate studies. The interannual El Niño Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) are two phenomena containing quasi-periodicities of approximately 2.5 and 2.2 years. It is known that ENSO affects corn yield through weather patterns...

  3. ON THE RELATIVISTIC PRECESSION AND OSCILLATION FREQUENCIES OF TEST PARTICLES AROUND RAPIDLY ROTATING COMPACT STARS

    SciTech Connect

    Pachon, Leonardo A.; Rueda, Jorge A.; Valenzuela-Toledo, Cesar A. E-mail: jorge.rueda@icra.it

    2012-09-01

    Whether or not analytic exact vacuum (electrovacuum) solutions of the Einstein (Einstein-Maxwell) field equations can accurately describe the exterior space-time of compact stars still remains an interesting open question in relativistic astrophysics. As an attempt to establish their level of accuracy, the radii of the innermost stable circular orbits (ISCOs) of test particles given by analytic exterior space-time geometries have been compared with those given by numerical solutions for neutron stars (NSs) obeying a realistic equation of state (EOS). It has been so shown that the six-parametric solution of Pachon et al. (PRS) more accurately describes the NS ISCO radii than other analytic models do. We propose here an additional test of accuracy for analytic exterior geometries based on the comparison of orbital frequencies of neutral test particles. We compute the Keplerian, frame-dragging, and precession and oscillation frequencies of the radial and vertical motions of neutral test particles for the Kerr and PRS geometries and then compare them with the numerical values obtained by Morsink and Stella for realistic NSs. We identify the role of high-order multipole moments such as the mass quadrupole and current octupole in the determination of the orbital frequencies, especially in the rapid rotation regime. The results of this work are relevant to cast a separatrix between black hole and NS signatures and to probe the nuclear-matter EOS and NS parameters from the quasi-periodic oscillations observed in low-mass X-ray binaries.

  4. Advances in Rotational Seismic Measurements

    SciTech Connect

    Pierson, Robert; Laughlin, Darren; Brune, Robert

    2016-10-19

    Rotational motion is increasingly understood to be a significant part of seismic wave motion. Rotations can be important in earthquake strong motion and in Induced Seismicity Monitoring. Rotational seismic data can also enable shear selectivity and improve wavefield sampling for vertical geophones in 3D surveys, among other applications. However, sensor technology has been a limiting factor to date. The US Department of Energy (DOE) and Applied Technology Associates (ATA) are funding a multi-year project that is now entering Phase 2 to develop and deploy a new generation of rotational sensors for validation of rotational seismic applications. Initial focus is on induced seismicity monitoring, particularly for Enhanced Geothermal Systems (EGS) with fracturing. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, improved noise floors, robustness, and repeatability. This paper presents a summary of Phase 1 results and Phase 2 status.

  5. Keplerian Rotation of Our Galaxy?

    NASA Astrophysics Data System (ADS)

    Gnaciński, P.; Młynik, T.

    2017-04-01

    It is common to attribute a flat rotation curve to our Galaxy. However, in a recent paper, Galazutdinov et al. obtained a Keplerian rotation curve for interstellar clouds in the outer parts of the Galaxy. They calculated the distances from equivalent widths of interstellar CaII lines. The radial velocity was also measured on the interstellar CaII absorption line. We verify the results of Galazutdinov et al. based on observations of old open clusters. We propose that the observations of flat and Keplerian rotation curves may be caused by the assumption of circular orbits. The application of formulas derived with the assumption of circular orbits to elliptical ones may mimics the flat rotation curve. The interstellar clouds with cross-sections larger than stars may have almost circular orbits, and the derived rotation curve will be Keplerian.

  6. Optomechanics for absolute rotation detection

    NASA Astrophysics Data System (ADS)

    Davuluri, Sankar

    2016-07-01

    In this article, we present an application of optomechanical cavity for the absolute rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of absolute rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.

  7. Hip Rotational Velocities During the Full Golf Swing

    PubMed Central

    Gulgin, Heather; Armstrong, Charles; Gribble, Phillip

    2009-01-01

    Since labral pathology in professional golfers has been reported, and such pathology has been associated with internal/external hip rotation, quantifying the rotational velocity of the hips during the golf swing may be helpful in understanding the mechanism involved in labral injury. Thus, the purpose of this study was to determine the peak internal/external rotational velocities of the thigh relative to the pelvis during the golf swing. Fifteen female, collegiate golfers participated in the study. Data were acquired through high-speed three dimensional (3-D) videography using a multi-segment bilateral marker set to define the segments, while the subjects completed multiple repetitions of a drive. The results indicated that the lead hip peak internal rotational velocity was significantly greater than that of the trail hip external rotational velocity (p = 0.003). It appears that the lead hip of a golfer experiences much higher rotational velocities during the downswing than that of the trail hip. In other structures, such as the shoulder, an increased risk of soft tissue injury has been associated with high levels of rotational velocity. This may indicate that, in golfers, the lead hip may be more susceptible to injury such as labral tears than that of the trailing hip. Key points Lead hip of golfer experiences significantly higher rotational velocities than the trail hip. Golfers may be more susceptible to injuries on the lead hip. Clubhead velocities were consistent with elite female golfers. PMID:24149541

  8. Geometry of tracer trajectories in turbulent rotating convection

    NASA Astrophysics Data System (ADS)

    Alards, Kim; Rajaei, Hadi; Kunnen, Rudie; Toschi, Federico; Clercx, Herman

    2016-11-01

    In Rayleigh-Bénard convection rotation is known to cause transitions in flow structures and to change the level of anisotropy close to the horizontal plates. To analyze this effect of rotation, we collect curvature and torsion statistics of passive tracer trajectories in rotating Rayleigh-Bénard convection, using both experiments and direct numerical simulations. In previous studies, focusing on homogeneous isotropic turbulence (HIT), curvature and torsion PDFs are found to reveal pronounced power laws. In the center of the convection cell, where the flow is closest to HIT, we recover these power laws, regardless of the rotation rate. However, near the top plate, where we expect the flow to be anisotropic, the scaling of the PDFs deviates from the HIT prediction for lower rotation rates. This indicates that anisotropy clearly affects the geometry of tracer trajectories. Another effect of rotation is observed as a shift of curvature and torsion PDFs towards higher values. We expect this shift to be related to the length scale of typical flow structures. Using curvature and torsion statistics, we can characterize how these typical length scales evolve under rotation and moreover analyze the effect of rotation on more complicated flow characteristics, such as anisotropy.

  9. Hip rotational velocities during the full golf swing.

    PubMed

    Gulgin, Heather; Armstrong, Charles; Gribble, Phillip

    2009-01-01

    Since labral pathology in professional golfers has been reported, and such pathology has been associated with internal/external hip rotation, quantifying the rotational velocity of the hips during the golf swing may be helpful in understanding the mechanism involved in labral injury. Thus, the purpose of this study was to determine the peak internal/external rotational velocities of the thigh relative to the pelvis during the golf swing. Fifteen female, collegiate golfers participated in the study. Data were acquired through high-speed three dimensional (3-D) videography using a multi-segment bilateral marker set to define the segments, while the subjects completed multiple repetitions of a drive. The results indicated that the lead hip peak internal rotational velocity was significantly greater than that of the trail hip external rotational velocity (p = 0.003). It appears that the lead hip of a golfer experiences much higher rotational velocities during the downswing than that of the trail hip. In other structures, such as the shoulder, an increased risk of soft tissue injury has been associated with high levels of rotational velocity. This may indicate that, in golfers, the lead hip may be more susceptible to injury such as labral tears than that of the trailing hip. Key pointsLead hip of golfer experiences significantly higher rotational velocities than the trail hip.Golfers may be more susceptible to injuries on the lead hip.Clubhead velocities were consistent with elite female golfers.

  10. An Improved Model of Cryogenic Propellant Stratification in a Rotating, Reduced Gravity Environment

    NASA Technical Reports Server (NTRS)

    Oliveira, Justin; Kirk, Daniel R.; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

    2007-01-01

    This paper builds on a series of analytical literature models used to predict thermal stratification within rocket propellant tanks. The primary contribution to the literature is to add the effect of tank rotation and to demonstrate the influence of rotation on stratification times and temperatures. This work also looks levels of thermal stratification for generic propellant tanks (cylindrical shapes) over a parametric range of upper-stage coast times, heating levels, rotation rates, and gravity levels.

  11. Magnetostrophic Rotating Magnetoconvection

    NASA Astrophysics Data System (ADS)

    King, Eric; Aurnou, Jonathan

    2016-11-01

    Planetary magnetic fields are generated by turbulent convection within their vast interior liquid metal cores. Although direct observation is not possible, this liquid metal circulation is thought to be dominated by the controlling influences of Coriolis and Lorentz forces. Theory famously predicts that local-scale convection naturally settles into the so-called magnetostrophic state, where the Coriolis and Lorentz forces partially cancel, and convection is optimally efficient. To date, no laboratory experiments have reached the magnetostrophic regime in turbulent liquid metal convection. Furthermore, computational dynamo simulations have as yet failed to produce a globally magnetostrophic dynamo, which has led some to question the existence of the magnetostrophic state. Here, we present results from the first turbulent magnetostrophic rotating magnetoconvection experiments using the liquid metal gallium. We find that turbulent convection in the magnetostrophic regime is, in fact, maximally efficient. The experimental results clarify these previously disparate results, suggesting that the fluid dynamics saturate in magnetostrophic balance within turbulent liquid metal, planetary cores. The authors thank the NSF Geophysics Program for financial support.

  12. Simulating rotational grazing management.

    PubMed

    Cros, M J; Duru, M; Garcia, F; Martin-Clouaire, R

    2001-09-01

    Dairy systems predominantly based on rotational grazing are notoriously hard to manage. In order to ensure profitability, this type of production requires quite good organisation, planning, and operating capability on the part of the farmer. A simulation-based decision support system, called SEPATOU, has been developed for this purpose. At the core of the decision support approach lies an explicit and rigorous modelling of the management strategy that underlies a dairy farmer's decision-making behaviour (real or hypothetical). The SEPATOU system is a discrete-event simulator that reproduces the day-to-day dynamics of the farmer's decision process and the response of the controlled biophysical system for which models of grass growth, animal consumption, and milk production are used. SEPATOU provides the means to evaluate and compare tentative strategies by simulating their application throughout the production season under different hypothetical weather conditions. The relative worth of a strategy can be assessed by analysing the effects on the biophysical system and their variability across the representative range of possible conditions that is considered. The activities to be managed concern the type and amount of conserved feed, where to fertilise and how much, the choice of fields to harvest, and most importantly, which field to graze next. Typically, SEPATOU is designed to be used by extension services and farming system scientists. It is implemented in C++ and is currently undergoing a validation process with the intended users.

  13. A comparison of quasi-symmetries in stellarators

    NASA Astrophysics Data System (ADS)

    Johnson, Alex; Ware, Andrew

    2016-10-01

    This work explores the differences between the equilibrium, stability and transport properties of quasi-helically (QH) symmetric, quasi-axisymmetric (QA) and quasi-poloidally (QP) symmetric stellarator configurations with the same major radius, aspect ratio, average magnetic field strength, plasma β and pressure profiles. Previous work on quasi-symmetry in stellarators has typically focused on one type of quasi-symmetry. Optimized stellarators have been developed for QH, QA and QP configurations but at very different plasma parameters. In this work computational studies of optimized cases of all three cases have been undertaken. Results of the studies will be presented. Work supported by U.S. Department of Energy under Grant DE-FG02-03ER54699 at the University of Montana.

  14. Differential rotation in rapidly rotating F-stars

    NASA Astrophysics Data System (ADS)

    Reiners, A.; Schmitt, J. H. M. M.

    2003-12-01

    We obtained high quality spectra of 135 stars of spectral types F and later and derived ``overall'' broadening functions in selected wavelength regions utilizing a Least Squares Deconvolution (LSD) procedure. Precision values of the projected rotational velocity v \\sini were derived from the first zero of the Fourier transformed profiles and the shapes of the profiles were analyzed for effects of differential rotation. The broadening profiles of 70 stars rotating faster than v \\sini = 45 km s-1 show no indications of multiplicity nor of spottedness. In those profiles we used the ratio of the first two zeros of the Fourier transform q_2/q_1 to search for deviations from rigid rotation. In the vast majority the profiles were found to be consistent with rigid rotation. Five stars were found to have flat profiles probably due to cool polar caps, in three stars cuspy profiles were found. Two out of those three cases may be due to extremely rapid rotation seen pole on, only in one case (v \\sini = 52 km s-1) is solar-like differential rotation the most plausible explanation for the observed profile. These results indicate that the strength of differential rotation diminishes in stars rotating as rapidly as v \\sini >~ 50 km s-1. Table A.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/813 Based on observations collected at the European Southern Observatory, La Silla, 69.D-0015(B).

  15. Evidence of high-frequency/small-scale turbulence in the Cygnus region and anomalous Faraday rotation

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2017-01-01

    Faraday effect - a common and useful probe of cosmic magnetic fields - is the result of magnetically-induced birefringence in plasmas causing rotation of the polarization plane of a linearly polarized electromagnetic wave. Classically, the rotation angle scales with the wavelength as Δϕ =RMλ2 , where RM is the rotation measure. Although a typical RM in the Milky Way is of the order of a few hundred to a few thousand, a famous Cygnus region shows anomalously small, even negative rotation measures. Moreover, Faraday rotation measurements seem to be inconsistent with the standard λ2-law. We argue that fast micro-turbulence can cause this anomaly. We demonstrate that electromagnetic high-frequency and/or small-scale fluctuations can lead to effective plasma collisionality by scattering electrons over pitch-angle. We show that such quasi-collisionality radically alters Faraday rotation and other radiative transport properties, e.g., absorption, transmission and reflection. Thus, we explain the Cygnus puzzle by anomalous Faraday rotation in a thin ``blanket'' of highly turbulent plasma at the front of an interstellar bubble/shock. Supported by DOE grant DE-SC0016368.

  16. Review of quasi-optical gyrotron development

    NASA Astrophysics Data System (ADS)

    Fliflet, A. W.; Hargreaves, T. A.; Fischer, R. P.; Manheimer, W. M.; Sprangle, P.

    1990-03-01

    There is currently a need for megawatt average power sources of 100-600 GHz radiation for electron cyclotron heating of fusion plasmas. One of the leading candidates for such a source, the conventional wave guide cavity gyrotron,(1) has produced impressive output powers and efficiencies at frequencies up to about 300 GHz. However, this gyrotron configuration is limited at high frequencies by high ohmic heating and problems with transverse mode competition due to the highly overmoded configuration, and with beam collection, since the beam must be collected along a section of the output waveguide. The quasi-optical gyrotron (QOG), first proposed in 1980 by Sprangle, Vomvoridis, and Manheimer,(3) features an open resonator formed by a pair of spherical mirrors instead of a waveguide resonator and has the potential for overcoming each of these limitations. The resonator mirrors can be well removed from the beam-wave interaction region, allowing a large volume for the interaction and low ohmic heating densities at the mirrors. The beam direction is transverse to the resonator so that beam collection is separate from the output waveguide. This geometry is particularly well suited to the use of a depressed collector for electron beam energy recovery. The QOG operates in the lowest-order transverse (TEMool) Guassian mode of the resonator, higher-order transverse modes being effectively suppressed by higher diffraction losses. This paper reviews recent progress toward the development of high-power quasi-optical gyrotrons for ECRH of fusion plasmas. It includes an overview of gyrotron theory in terms of normalized variables as they apply to the quasi-optical gyrotron for operation both in the fundamental and the higher harmonics. Scaling equations for the output power and resonator mirror heating by the RF are given. The design tradeoffs between annular and sheet electron beams are discussed as is the issue of beam space-charge depression in the open resonator. Recent

  17. General-relativistic rotation laws in rotating fluid bodies

    NASA Astrophysics Data System (ADS)

    Mach, Patryk; Malec, Edward

    2015-06-01

    We formulate new general-relativistic extensions of Newtonian rotation laws for self-gravitating stationary fluids. They have been used to rederive, in the first post-Newtonian approximation, the well-known geometric dragging of frames. We derive two other general-relativistic weak-field effects within rotating tori: the recently discovered dynamic antidragging and a new effect that measures the deviation from the Keplerian motion and/or the contribution of the fluids self-gravity. One can use the rotation laws to study the uniqueness and the convergence of the post-Newtonian approximations as well as the existence of the post-Newtonian limits.

  18. Micro-Doppler frequency comb generation by rotating wire scatterers

    NASA Astrophysics Data System (ADS)

    Kozlov, V.; Filonov, D.; Yankelevich, Y.; Ginzburg, P.

    2017-03-01

    Electromagnetic scattering in accelerating reference frames inspires a variety of phenomena, requiring employment of general relativity for their description. While the 'quasi-stationary field' analysis could be applied to slowly-accelerating bodies as a first-order approximation, the scattering problem remains fundamentally nonlinear in boundary conditions, giving rise to multiple frequency generation (micro-Doppler shifts). Here a frequency comb, generated by an axially rotating subwavelength (cm-range) wires is analyzed theoretically and observed experimentally by illuminating the system with a 2 GHz carrier wave. Highly accurate 'lock in' detection scheme enables factorization of the carrier and observation of multiple peaks in a comb. The Hallen integral equation is employed for deriving the currents induced on the scatterer and a set of coordinate transformations, connecting laboratory and rotating frames, is applied in order to make analytical predictions of the spectral positions and amplitudes of the frequency comb peaks. Numeric simulations of the theoretic framework reveal the dependence of the micro-Doppler peaks on the wire's length and its axis of rotation. Unique spectral signature of micro-Doppler shifts could enable resolving internal structures of scatterers and mapping their accelerations in space, which is valuable for a variety of applications spanning from targets identification to stellar radiometry.

  19. Spin-down of a rotating air hockey disk

    NASA Astrophysics Data System (ADS)

    Weidman, Patrick; Julien, Keith

    2013-11-01

    We extend the work of Weidman (APS, DFD 2008) on the steady float height of a rotating disk to formulate and solve for the unsteady behavior of spin-down to rest. A similarity reduction of the Navier-Stokes equations reduces the problem to a coupled pair of partial differential equations in space and time. For a disk of fixed radius and density, the PDE's must be solved taking into account constraints imposed by the aerodynamic torque and aerodynamic lift. Thus the full solution for the unsteady azimuthal and axial dynamics of the disk can be obtained for given initial values of disk Reynolds number R = W h / ν and dimensionless disk rotation speed S =√{ 2} Ωh / W , where h is the float height, W is the fluid levitation velocity, Ω is the disk rotation rate, and ν is the kinematic viscosity of the fluid. Integrations reveal interesting families of solutions when plotted over steady solution curves in R- S parameter space and vindicate the quasi-steady spin-down theory reported in earlier work, valid only in a restricted region of parameter space.

  20. EVOLUTION OF ROTATIONAL VELOCITIES OF A-TYPE STARS

    SciTech Connect

    Yang Wuming; Bi Shaolan; Tian Zhijia; Meng Xiangcun E-mail: yangwuming@bnu.edu.cn

    2013-03-10

    The equatorial velocity of A-type stars undergoes an acceleration in the first third of the main sequence (MS) stage, but the velocity decreases as if the stars were not undergoing any redistribution of angular momentum in the external layers in the last stage of the MS phase. Our calculations show that the acceleration and the decrease of the equatorial velocity can be reproduced by the evolution of the differential rotation zero-age MS model with the angular momentum transport caused by hydrodynamic instabilities during the MS stage. The acceleration results from the fact that the angular momentum stored in the interiors of the stars is transported outward. In the last stage, the core and the radiative envelope are uncoupling, and the rotation of the envelope is a quasi-solid rotation; the uncoupling and the expansion of the envelope indicate that the decrease of the equatorial velocity approximately follows the slope for the change in the equatorial velocity of the model without any redistribution of angular momentum. When the fractional age 0.3 {approx}< t/t{sub MS} {approx}< 0.5, the equatorial velocity remains almost constant for stars whose central density increases with age in the early stage of the MS phase, while the velocity decreases with age for stars whose central density decreases with age in the early stage of the MS phase.

  1. Gaussian MRF rotation-invariant features for image classification.

    PubMed

    Deng, Huawu; Clausi, David A

    2004-07-01

    Features based on Markov random field (MRF) models are sensitive to texture rotation. This paper develops an anisotropic circular Gaussian MRF (ACGMRF) model for retrieving rotation-invariant texture features. To overcome the singularity problem of the least squares estimate method, an approximate least squares estimate method is designed and implemented. Rotation-invariant features are obtained from the ACGMRF model parameters using the discrete Fourier transform. The ACGMRF model is demonstrated to be a statistical improvement over three published methods. The three methods include a Laplacian pyramid, an isotropic circular GMRF (ICGMRF), and gray level cooccurrence probability features.

  2. Cold tests and high power measurements on an advanced quasi-optical mode converter for a 118 GHz gyrotron

    SciTech Connect

    Braz, O.; Losert, M.; Moebius, A.; Thumm, M. |

    1995-12-31

    This paper reports on cold test and high power measurements of the improved, dimple type quasi-optical mode converter for the 118 GHz, 0.5 MW, 210 s TE{sub 22,6} gyrotron oscillator collaboratively developed by CEA Cadarache, CRPP Lausanne, FZK Karlsruhe and Thomson Tubes Electroniques Velizy. For the low power measurements the required rotating TE{sub 22,6} mode was generated in a coaxial cavity using quasioptical techniques. The high power measurements were performed on the gyrotron output beam using an infrared camera. The evaluated mode purity of the linearly polarized fundamental Gaussian output mode is (96 {plus_minus} 1)% in agreement with calculations.

  3. Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

    DOE PAGES

    Edlund, E. M.; Ji, H.

    2015-10-06

    Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

  4. Toroidal rotation studies in KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, S. G.; Lee, H. H.; Yoo, J. W.; Kim, Y. S.; Ko, W. H.; Terzolo, L.; Bitter, M.; Hill, K.; KSTAR Team

    2014-10-01

    Investigation of the toroidal rotation is one of the most important topics for the magnetically confined fusion plasma researches since it is essential for the stabilization of resistive wall modes and its shear plays an important role to improve plasma confinement by suppressing turbulent transport. The most advantage of KSTAR tokamak for toroidal rotation studies is that it equips two main diagnostics including the high-resolution X-ray imaging crystal spectrometer (XICS) and charge exchange spectroscopy (CES). Simultaneous core toroidal rotation and ion temperature measurements of different impurity species from the XICS and CES have shown in reasonable agreement with various plasma discharges in KSTAR. It has been observed that the toroidal rotation in KSTAR is faster than that of other tokamak devices with similar machine size and momentum input. This may due to an intrinsically low toroidal field ripple and error field of the KSTAR device. A strong braking of the toroidal rotation by the n = 1 non-resonant magnetic perturbations (NRMPs) also indicates these low toroidal field ripple and error field. Recently, it has been found that n = 2 NRMPs can also damp the toroidal rotation in KSTAR. The detail toroidal rotation studies will be presented. Work supported by the Korea Ministry of Science, ICT and Future Planning under the KSTAR project.

  5. Rotational motion of Vesta

    NASA Astrophysics Data System (ADS)

    Rambaux, N.; Asmar, S. W.; Konopliv, A. S.

    2012-09-01

    Vesta is the second most massive body of the asteroid belt and contains a giant impact and a differentiated interior. Constraints on internal structure can be inferred from various observations such as gravity field measurements [1]. Especially, detailed knowledge of the rotational motion can help constrain the mass distribution inside the body, which in turn can lead to information on its history. Here, we compute the polar motion, precession-nutation, and length-of-day variations of Vesta. The Vesta's Pole position in space has been obtained by Dawn mission [1] and the orbital pole of Vesta at J2000 can be obtained from the Horizons ephemerides [2]. The obliquity, defined as the angle between the normal to the orbital plane and the figure axis, brings information on the moment of inertia if it has reached its equilibrium position [3], the present value from observations is around 27 degrees. That is far from the ˜ 0.03 deg expected for the equilibrium position. In addition, the required timescale to fully damped the obliquity appears to be very long following the same approach developed in [4]. Thus, it appears that the obliquity of Vesta has not yet relaxed in its Cassini state. The figure of Vesta appears to be triaxial and the Sun exerts a non-zero torque. By following the approach developed for the Earth [e.g. 5] and Ceres [4], we compute the nutation of Vesta. The nutational motion of Vesta is dominated by the semi-annual nutation (996 milli-arcseconds or 1.26 m surface displacement) related to the large obliquity of Vesta, and then terms related to harmonics and also to the planet's mean longitude. The detection of such small displacement requires tracking of Vesta's surface with high precision. The precession time of the axis of Vesta is very long, about 179,000 years.

  6. A slowly rotating impeller in a rapidly rotating fluid

    NASA Astrophysics Data System (ADS)

    Machicoane, Nathanael; Moisy, Frederic; Cortet, Pierre-Philippe; Instability, waves; turbulence Team

    2016-11-01

    We characterize the two-dimensionalization process in the turbulent flow produced by an impeller rotating at a rate ω in a fluid rotating at a rate Ω around the same axis for Rossby number Ro = ω / Ω down to 0.01. The flow can be described as the superposition of a large-scale vertically invariant global rotation and small-scale shear layers detached from the impeller blades. As Ro decreases, the large-scale flow is subjected to azimuthal modulations. In this regime, the shear layers can be described in terms of wakes of inertial waves traveling with the blades, originating from the velocity difference between the non-axisymmetric large-scale flow and the blade rotation. The wakes are well defined and stable at low Rossby number, but they become disordered and interact nonlinearly at Ro of order of 1.

  7. Rotating Stars Can Help Planets Become Habitable

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-12-01

    What characteristics must a terrestrial planet exhibit to have the potential to host life? Orbiting within the habitable zone of its host star is certainly a good start, but theres another important aspect: the planet has to have the right atmosphere. A recent study has determined how host stars can help their planets to lose initial, enormous gaseous envelopes and become more Earth-like.Collecting An EnvelopeWhen a terrestrial planet forms inside a gaseous protoplanetary disk, it can accumulate a significant envelope of hydrogen gas causing the planet to bear more similarity to a mini-Neptune than to Earth. Before the planet can become habitable, it must shed this enormous, primordial hydrogen envelope, so that an appropriate secondary atmosphere can form.So what determines whether a planet can get rid of its protoatmosphere? The dominant process for shedding a hydrogen atmosphere is thermal mass loss: as the planets upper atmosphere is heated by X-ray and extreme-ultraviolet (XUV) radiation from the host star, the envelope evaporates.A Critical DependenceIn a recent study led by Colin Johnstone (University of Vienna), a team of scientists has developed models of this evaporation process for hydrogen planetary atmospheres. In particular, Johnstone and collaborators examine how the host stars initial rotation rate which strongly impacts the stars level of XUV activity affects the degree to which the planets hydrogen atmosphere is evaporated, and the rate at which the evaporation occurs.The authors findings can be illustrated with the example of an Earth-mass planet located in the habitable zone of a solar-mass star. In this case, the authors find four interesting regimes (shown in the plot to the right):Evolution of the hydrogen protoatmosphere of an Earth-mass planet in the habitable zone of a solar-mass star. The four lettered cases describe different initial atmospheric masses. The three curves for each case describe the stellar rotation rate: slow (red

  8. [Optical path difference in off-plane quasi-Littrow dispersion mountings].

    PubMed

    Zhang, Yin-Xin; Yang, Huai-Dong; Huang, Zhan-Hua; Jin, Guo-Fan

    2013-07-01

    The present paper analyzes the relative relation between the meridian and sagittal rays in off-plane quasi-Littrow (OP-QL) dispersion mountings. It's concluded that the off-plane angle will cause the rotation of the beam and result in the mismatch between the sagittal beams on different optical elements. Therefore the total optical path difference (OPD) should be an accumulation of corresponding beams instead of the sagittal beam of each element itself. Then, a directional derivative based method is put forward to calculate the OPD for spherical mirrors in various directions. Based on the method, the numerical OPD for OP-QL mountings is solved. Finally, this methodology is validated with both echelette and echelle examples.

  9. The solar magnetic activity band interaction and instabilities that shape quasi-periodic variability

    PubMed Central

    McIntosh, Scott W.; Leamon, Robert J.; Krista, Larisza D.; Title, Alan M.; Hudson, Hugh S.; Riley, Pete; Harder, Jerald W.; Kopp, Greg; Snow, Martin; Woods, Thomas N.; Kasper, Justin C.; Stevens, Michael L.; Ulrich, Roger K.

    2015-01-01

    Solar magnetism displays a host of variational timescales of which the enigmatic 11-year sunspot cycle is most prominent. Recent work has demonstrated that the sunspot cycle can be explained in terms of the intra- and extra-hemispheric interaction between the overlapping activity bands of the 22-year magnetic polarity cycle. Those activity bands appear to be driven by the rotation of the Sun's deep interior. Here we deduce that activity band interaction can qualitatively explain the ‘Gnevyshev Gap'—a well-established feature of flare and sunspot occurrence. Strong quasi-annual variability in the number of flares, coronal mass ejections, the radiative and particulate environment of the heliosphere is also observed. We infer that this secondary variability is driven by surges of magnetism from the activity bands. Understanding the formation, interaction and instability of these activity bands will considerably improve forecast capability in space weather and solar activity over a range of timescales. PMID:25849045

  10. The solar magnetic activity band interaction and instabilities that shape quasi-periodic variability.

    PubMed

    McIntosh, Scott W; Leamon, Robert J; Krista, Larisza D; Title, Alan M; Hudson, Hugh S; Riley, Pete; Harder, Jerald W; Kopp, Greg; Snow, Martin; Woods, Thomas N; Kasper, Justin C; Stevens, Michael L; Ulrich, Roger K

    2015-04-07

    Solar magnetism displays a host of variational timescales of which the enigmatic 11-year sunspot cycle is most prominent. Recent work has demonstrated that the sunspot cycle can be explained in terms of the intra- and extra-hemispheric interaction between the overlapping activity bands of the 22-year magnetic polarity cycle. Those activity bands appear to be driven by the rotation of the Sun's deep interior. Here we deduce that activity band interaction can qualitatively explain the 'Gnevyshev Gap'—a well-established feature of flare and sunspot occurrence. Strong quasi-annual variability in the number of flares, coronal mass ejections, the radiative and particulate environment of the heliosphere is also observed. We infer that this secondary variability is driven by surges of magnetism from the activity bands. Understanding the formation, interaction and instability of these activity bands will considerably improve forecast capability in space weather and solar activity over a range of timescales.

  11. Anharmonic behavior in the multisubunit protein apoferritin as revealed by quasi-elastic neutron scattering.

    PubMed

    Telling, Mark T F; Neylon, Cameron; Kilcoyne, Susan H; Arrighi, Valeria

    2008-09-04

    Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law harmonic behavior in lyophilized and hydrated apoferritin, a naturally occurring, multisubunit protein. Whereas analysis of the measured mean squared displacement (msd) parameter reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a hydration-independent inflection is observed at 100 K. The mechanism responsible for this low-temperature anharmonic response is further investigated, via analysis of the elastic incoherent neutron scattering intensity, by applying models developed to describe side-group motion in glassy polymers. Our results suggest that the deviation from harmonic behavior is due to the onset of methyl group rotations which exhibit a broad distribution of activated processes ( E a,ave = 12.2 kJ.mol (-1), sigma = 5.0 kJ x mol (-1)). Our results are likened to those reported for other proteins.

  12. Experiments and modelling of active quasi-single helicity regime generation in a reversed field pinch

    NASA Astrophysics Data System (ADS)

    Frassinetti, L.; Brunsell, P. R.; Drake, J. R.

    2009-07-01

    The interaction of a static resonant magnetic perturbation (RMP) with a tearing mode (TM) is becoming a relevant topic in fusion plasma physics. RMPs can be generated by active coils and then used to affect the properties of TMs and of the corresponding magnetic islands. This paper shows how the feedback system of the EXTRAP T2R reversed field pinch (RFP) can produce a RMP that affects a rotating TM and stimulate the transition to the so-called quasi-single helicity (QSH) regime, a RFP plasma state characterized by a magnetic island surrounded by low magnetic chaos. The application of the RMP can increase the QSH probability up to 10% and enlarge the size of the corresponding island. Part of the experimental results are supported by a theoretical study that models the effect of the active coils on the magnetic island.

  13. Delayed feedback control and phase reduction of unstable quasi-periodic orbits.

    PubMed

    Ichinose, Natsuhiro; Komuro, Motomasa

    2014-09-01

    The delayed feedback control (DFC) is applied to stabilize unstable quasi-periodic orbits (QPOs) in discrete-time systems. The feedback input is given by the difference between the current state and a time-delayed state in the DFC. However, there is an inevitable time-delay mismatch in QPOs. To evaluate the influence of the time-delay mismatch on the DFC, we propose a phase reduction method for QPOs and construct a phase response curve (PRC) from unstable QPOs directly. Using the PRC, we estimate the rotation number of QPO stabilized by the DFC. We show that the orbit of the DFC is consistent with the unstable QPO perturbed by a small state difference resulting from the time-delay mismatch, implying that the DFC can certainly stabilize the unstable QPO.

  14. Delayed feedback control and phase reduction of unstable quasi-periodic orbits

    NASA Astrophysics Data System (ADS)

    Ichinose, Natsuhiro; Komuro, Motomasa

    2014-09-01

    The delayed feedback control (DFC) is applied to stabilize unstable quasi-periodic orbits (QPOs) in discrete-time systems. The feedback input is given by the difference between the current state and a time-delayed state in the DFC. However, there is an inevitable time-delay mismatch in QPOs. To evaluate the influence of the time-delay mismatch on the DFC, we propose a phase reduction method for QPOs and construct a phase response curve (PRC) from unstable QPOs directly. Using the PRC, we estimate the rotation number of QPO stabilized by the DFC. We show that the orbit of the DFC is consistent with the unstable QPO perturbed by a small state difference resulting from the time-delay mismatch, implying that the DFC can certainly stabilize the unstable QPO.

  15. Contribution of GPS techniques to the densification and to quasi-real Universal Time estimation.

    NASA Astrophysics Data System (ADS)

    Gambis, D.; Eisop, E.

    The determination of Universal Time is mainly based on the inertial VLBI technique. Due to the difficulty of determining the long-term behaviour of the non rotating system realized through the orbit orientation, Universal Time cannot be accurately derived from GPS technique; still GPS technique gives information on the high-frequency UT1 behaviour on time scales limited to a couple of months. This signal can be used for densification of the UT1 series as well as for UT1 extensions on a quasi-real-time basis from the current VLBI available value. In that case, errors are about 60 microseconds for a 5-day interval. This represents an improvement of an order of magnitude with respect to the current prediction of UT1 based on auto-regressive processes.

  16. Cooling system for rotating machine

    DOEpatents

    Gerstler, William Dwight; El-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Alexander, James Pellegrino; Quirion, Owen Scott; Palafox, Pepe; Shen, Xiaochun; Salasoo, Lembit

    2011-08-09

    An electrical machine comprising a rotor is presented. The electrical machine includes the rotor disposed on a rotatable shaft and defining a plurality of radial protrusions extending from the shaft up to a periphery of the rotor. The radial protrusions having cavities define a fluid path. A stationary shaft is disposed concentrically within the rotatable shaft wherein an annular space is formed between the stationary and rotatable shaft. A plurality of magnetic segments is disposed on the radial protrusions and the fluid path from within the stationary shaft into the annular space and extending through the cavities within the radial protrusions.

  17. Orbital, Rotational, and Climatic Interactions

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G. (Editor)

    1992-01-01

    The report of an international meeting on the topic of Orbital, Rotational, and Climatic Interactions, which was held 9-11 Jul. 1991 at the Johns Hopkins University is presented. The meeting was attended by 22 researchers working on various aspects of orbital and rotational dynamics, paleoclimate data analysis and modeling, solid-Earth deformation studies, and paleomagnetic analyses. The primary objective of the workshop was to arrive at a better understanding of the interactions between the orbital, rotational, and climatic variations of the Earth. This report contains a brief introduction and 14 contributed papers which cover most of the topics discussed at the meeting.

  18. Antimagnetic rotation in 104Pd

    NASA Astrophysics Data System (ADS)

    Rather, N.; Roy, S.; Datta, P.; Chattopadhyay, S.; Goswami, A.; Nag, S.; Palit, R.; Pal, S.; Saha, S.; Sethi, J.; Trivedi, T.; Jain, H. C.

    2014-06-01

    The electric quadrupole transition rates for the high-spin yrast states of 104Pd have been measured by using the Doppler-shift attenuation method. These values decrease with the increase of angular momentum, which can be associated with the phenomenon of antimagnetic rotation. In the present work, a numerical calculation based on the semiclassical particle plus rotor model for antimagnetic rotation has been employed, giving a good description of the experimental Routhian and the transition rates and providing conclusive evidence of antimagnetic rotation in a nucleus other than cadmium.

  19. Venus' rotation and atmospheric tides

    NASA Technical Reports Server (NTRS)

    Ingersoll, A. P.; Dobrovolskis, A. R.

    1978-01-01

    On the basis of a presented theory, it is suggested that Venus' current rotation is a stable balance between atmospheric and solar body tides. The theory is concerned with Venus' atmospheric tides, driven by solar heating, and how these tides could serve as a third torque to balance the effects of solar body torque and to maintain a stable equilibrium resonance with regard to the earth's gravitational effects. In the absence of the atmospheric tidal torque, or some other torque, it would be expected that Venus would be despun until synchronous rotation (one side always facing the sun) is attained, rather than retain the retrograde rotation period of 243 days.

  20. Axial gap rotating electrical machine

    DOEpatents

    None

    2016-02-23

    Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.