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.
Hydrodynamic turbulence in quasi-Keplerian rotating flows
NASA Astrophysics Data System (ADS)
Shi, Liang; Hof, Björn; Rampp, Markus; Avila, Marc
2017-04-01
We report a direct-numerical-simulation study of the Taylor-Couette flow in the quasi-Keplerian regime at shear Reynolds numbers up to O (105) . Quasi-Keplerian rotating flow has been investigated for decades as a simplified model system to study the origin of turbulence in accretion disks that is not fully understood. The flow in this study is axially periodic and thus the experimental end-wall effects on the stability of the flow are avoided. Using optimal linear perturbations as initial conditions, our simulations find no sustained turbulence: the strong initial perturbations distort the velocity profile and trigger turbulence that eventually decays.
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.
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
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).
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.
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.
The quasi-rigid rotation of coronal magnetic fields
NASA Technical Reports Server (NTRS)
Wang, Y.-M.; Sheeley, N. R., Jr.; Nash, A. G.; Shampine, L. R.
1988-01-01
Spherical harmonic analysis and numerical simulations are used to study the rotational properties of the coronal magnetic field under the assumption that it can be approximated by a current-free extension of the photospheric field. It is found that the rotation rate in the outer corona is determined, principally, by coronal filtering, the global averages of the photospheric rotation rate, and ongoing source eruptions. The present model is able to account for observationally inferred rotational properties. It is suggested that the coronal rotation rate accelerates gradually due to the equatorward migration of sunspots, and that the 27-day equatorial period is approached toward sunspot minimum as the decaying photospheric flux becomes localized near the equator.
Neutron scattering observation of quasi-free rotations of water confined in carbon nanotubes
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
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.
Scaling in three-dimensional and quasi-two-dimensional rotating turbulent flows
NASA Astrophysics Data System (ADS)
Baroud, Charles N.; Plapp, Brendan B.; Swinney, Harry L.; She, Zhen-Su
2003-08-01
We have made velocity time series measurements (using hot film probes) and velocity field measurements (using particle image velocimetry) on turbulent flow in a rotating annulus. For low annulus rotation rates the Rossby number was of order unity and the flow was three-dimensional (3D), but at high rotation rates the Rossby number was only about 0.1, comparable to the value for oceans and the atmosphere on large length scales. The low Rossby number (quasi-geostrophic) flow was nearly two-dimensional (2D), as expected from the Taylor-Proudman theorem. For the 3D flow we found that the probability distribution function (PDF) for velocity differences along the direction of the flow, δv(d)=v(x0+d)-v(x0), was Gaussian for large separations d and non-Gaussian (with exponential tails) for small d, as has been found for nonrotating turbulent flows. However, for low Rossby number flow, the PDF was self-similar (independent of d) and non-Gaussian. The exponents characterizing the structure functions, Sp=<(δv)p>˜dζp were obtained by the extended self-similarity method. For 3D flow the exponents departed from p/3 with increasing p, as has been found for turbulence in nonrotating flows, while for the quasi-2D turbulent flow, the exponents increased linearly with p, as expected for a self-similar flow. We applied the β-test of the hierarchical structure model [She and Lévêque, Phys. Rev. Lett. 72, 336 (1994)] and found that β remained constant at β≃0.75 as the rotation was increased from the 3D to the 2D regime; this indicates that both the quasi-2D and 3D flows are highly intermittent. The PIV images provided another indication of the intermittency—both the quasi-2D and 3D flows had coherent vortices which could be distinguished from the background flow. We also applied the γ-test of the hierarchical structure model and found that γ increased from 0.18 for the 3D flow to 0.34 for the quasi-2D flow; the latter value is in accord with expectation for self
Maintenance of quasi-stationary waves in a 2-level quasi-geostrophic spectral model with topography
NASA Technical Reports Server (NTRS)
Yao, M. S.
1979-01-01
The maintenance of the quasi-stationary waves obtained through numerically integrating a 2-level quasi-geostrophic spectral model on a beta-plane is investigated. An idealized topography which has only wavenumber n in the zonal direction and the first mode in the meridional direction is used to force the quasi-stationary waves. It is shown that the topographical forcing is not necessarily the mechanism for maintaining the quasi-stationary waves.
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.
Spin-orbit coupling and chaotic rotation for coorbital bodies in quasi-circular orbits
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.
Quasi-static stop band with flexural metamaterial having zero rotational stiffness
NASA Astrophysics Data System (ADS)
Oh, Joo Hwan; Assouar, Badreddine
2016-09-01
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.
Quasi-static stop band with flexural metamaterial having zero rotational stiffness.
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.
Quasi-static stop band with flexural metamaterial having zero rotational stiffness
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
Quasi-3D Navier-Stokes model for a rotating airfoil
Shen, W.Z.; Soerensen, J.N.
1999-04-10
The design of blade shapes for wind turbines is typically based on employing the blade-element momentum-theory (BEM) with lift and drag forces determined from 2D measurements. The results obtained are reasonable in the vicinity of the design point, but in stalled conditions the BEM is known to underpredict the forces acting on the blades. Here, a quasi-3D model of the unsteady Navier-Stokes equations in a rotating frame of reference has been developed. The equations governing the flow past a rotating blade are approximated using an order of magnitude analysis on the spanwise derivatives. The model takes into account rotational effects and spanwise outflow at computing expenses in the order of what is typical for similar 2D calculations. Results are presented for both laminar and turbulent flows past blades in pure rotation. In the turbulent case the influence of small-scale turbulence is modelled by the one-equation Baldwin-Barth turbulence model. The computations demonstrate that the main influence of rotation is to increase the maximum lift.
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.
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.
Strong gravity effects of rotating black holes: quasi-periodic oscillations
NASA Astrophysics Data System (ADS)
Aliev, Alikram N.; Daylan Esmer, Göksel; Talazan, Pamir
2013-02-01
We explore strong gravity effects of the geodesic motion in the spacetime of rotating black holes in general relativity and braneworld gravity. We focus on the description of the motion in terms of three fundamental frequencies: the orbital frequency, the radial and vertical epicyclic frequencies. For a Kerr black hole, we perform a detailed numerical analysis of these frequencies at the innermost stable circular orbits and beyond them as well as at the characteristic stable orbits, at which the radial epicyclic frequency attains its highest value. We find that the values of the epicyclic frequencies for a class of stable orbits exhibit good qualitative agreement with the observed frequencies of the twin peaks quasi-periodic oscillations (QPOs) in some black hole binaries. We also find that at the characteristic stable circular orbits, where the radial (or the vertical) epicyclic frequency has maxima, the vertical and radial epicyclic frequencies exhibit an approximate 2:1 ratio even in the case of near-extreme rotation of the black hole. Next, we perform a similar analysis of the fundamental frequencies for a rotating braneworld black hole and argue that the existence of such a black hole with a negative tidal charge, whose angular momentum exceeds the Kerr bound in general relativity, does not confront with the observations of high-frequency QPOs.
Differential rotation in a solar-driven quasi-axisymmetric circulation. [of planetary atmospheres
NASA Technical Reports Server (NTRS)
Mayr, H. G.; Harris, I.; Chan, K. L.
1984-01-01
The concept of a quasi-axisymmetric circulation is used to explore the global scale dynamics of planetary atmospheres. A numerical circulation model applicable to Jupiter is presented, and an analytical study is performed elucidating the conditions leading to differential rotation in an atmosphere which is convectively unstable. A linear system forced by solar differential heating is considered, with nonlinear effects arising from advection being represented in the form of eddy diffusion. An empirical, latitudinal spectrum of the observed zonal wind field on Jupiter is discussed. Numerical solutions are presented which reveal banded wind fields with alternating and equatorial zonal jets and a multicellular Ferrel-Thomson meridional circulation consistent with the observed cloud striations on Jupiter. The vertical derivatives are parameterized to construct a simplified one-layer model.
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.
Subcritical convection of liquid metals in a rotating sphere using a quasi-geostrophic model
NASA Astrophysics Data System (ADS)
Guervilly, Céline; Cardin, Philippe
2016-12-01
We study nonlinear convection in a rapidly rotating sphere with internal heating for values of the Prandtl number relevant for liquid metals ($Pr\\in[10^{-2},10^{-1}]$). We use a numerical model based on the quasi-geostrophic approximation, in which variations of the axial vorticity along the rotation axis are neglected, whereas the temperature field is fully three-dimensional. We identify two separate branches of convection close to onset: (i) a well-known weak branch for Ekman numbers greater than $10^{-6}$, which is continuous at the onset (supercritical bifurcation) and consists of thermal Rossby waves, and (ii) a novel strong branch at lower Ekman numbers, which is discontinuous at the onset. The strong branch becomes subcritical for Ekman numbers of the order of $10^{-8}$. On the strong branch, the Reynolds number of the flow is greater than $10^3$, and a strong zonal flow with multiple jets develops, even close to the nonlinear onset of convection. We find that the subcriticality is amplified by decreasing the Prandtl number. The two branches can co-exist for intermediate Ekman numbers, leading to hysteresis ($Ek=10^{-6}$, $Pr=10^{-2}$). Nonlinear oscillations are observed near the onset of convection for $Ek=10^{-7}$ and $Pr=10^{-1}$.
Subcritical thermal convection of liquid metals in a rotating sphere using a quasi-geostrophic model
NASA Astrophysics Data System (ADS)
Cardin, P.; Guervilly, C.
2016-12-01
We study non-linear convection in a rapidly rotating sphere with internal heating for values of the Prandtl number relevant for liquid metals (10-2-1). We use a numerical model based on the quasi-geostrophic approximation, in which variations of the axial vorticity along the rotation axis are neglected, whereas the temperature field is fully three-dimensional. We identify two separate branches of convection close to onset: (i) a well-known weak branch for Ekman numbers greater than 10-6, which is continuous at the onset (supercritical bifurcation) and consists of the interaction of thermal Rossby waves, and (ii) a novel strong branch at lower Ekman numbers, which is discontinuous at the onset. The strong branch becomes subcritical for Ekman numbers of the order of 10-8. On the strong branch, the Reynolds number of the flow is greater than 1000, and a strong zonal flow with multiple jets develops, even close to the non-linear onset of convection. We find that the subcriticality is amplified by decreasing the Prandtl number. The two branches can co-exist for intermediate Ekman numbers, leading to hysteresis (E = 10-6, Pr =10-2). Non-linear oscillations are observed near the onset of convection for E = 10-7 and Pr = 10-1.
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.
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.
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.
Rotating toroidal equilibria of quasi-neutral and non-neutral plasmas
Hurricane, O.A.
1998-06-01
Starting from the fundamental ion and electron fluid equations, a {open_quotes}master{close_quotes} equilibrium equation set is constructed for axisymmetric toroidal plasmas. These equations retain the effects of different ion and electron densities, temperatures, sheared rotation, and electric forces. The master equation is then examined in various limits including the non-neutral plasma limit. An ordering is assumed which makes the effects of the Reynolds stress, pressure, magnetic stress, and electric field stress all comparable emphasizing the natural transition from the non-neutral case to the quasi-neutral one. For sub-relativistic flows, charge separation effects are only significant for nearly force-free plasmas. A set of equilibrium equations are derived for three different cases: (A) n{sub i}{approx}n{sub e}, (B) n{sub i}{ne}n{sub e}{ne}0, and (C) n{sub i}=0 and n{sub e}{ne}0. In the pure electron plasma case, the resulting equilibrium equation includes the effects of toroidal rotation, poloidal magnetic field, and electron pressure extending the equation of Daugherty and Levy [Phys. Fluids {bold 10}, 155 (1967)]. {copyright} {ital 1998 American Institute of Physics.}
Study of the crossing of quasi-energy levels in a four-level system
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)
Quasi-periodical variations of pulsars spin as mimicry of differential rotation
NASA Astrophysics Data System (ADS)
Kitiashvili, I.; Gusev, A.
2008-09-01
ABSTRACT Observation of pulsars is a powerful source of information for studying the dynamics and internal structure of neutron stars. Known about quasi-periodical fluctuations of the time-of-arrival of radiation(TOA) for some pulsars, which we explain as Chandler wobble, Free core nutation, Free inner core nutation and Inner core wobble in case three layer model. Using hamilton approximation to theory rotation of multilayer celestial bodies we estimate dynamical flattening for different layers for PSR B1828-11. It is known that an innate feature of pulsar radiation is high stability of the time-of-arrival (TOA) of pulses, and therefore the analysis of TOA fluctuations can reflect subtle effects of neutron stars dynamics. TOA variations of pulsars can be interpreted by three reasons: gravitational perturbation of pulsar by planetary bodies, peculiarities of a pulsar interior like Tkachenko oscillations and free precession motion, when axis of rotation do not coincide with vectors of the angular moment of solid crust, liquid outer core and crystal core. The radial velocity of a star is obtained by measuring the magnitude of the Doppler effect in its spectrum. Stars showing a small amplitude variation of the radial velocity can be interpreted as systems having planetary companions. Assuming that the pulsar PSR B1257+12 has a mass of 1:35M¯, the Keplerian orbital radii are 0.9, 1.4 and 2.1 AU and with masses are 3:1M©=sin(i), 10:2M©=sin(i), 4:6M©=sin(i), where i is the orbital inclination [7]. In 2000, Stairs, Lyne and Shemar reported about their discovery of long-term, highly-periodic and correlated variations of pulse shape and the rate of slow-down of the pulsar PSR B182811 with period variations approximately 1000, 500, 250 and 167 days, which may be a result of the spin axis caused by an asymmetry in the shape of the pulsar. The long-periodic precession phenomenon was also detected for a few pulsars: PSR 2217+47, PSR 0531+21, PSR B083345, PSR B182811, PSR B
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.
Rotational-vibrational structure of a quasi-linear molecule: CH/sub 2//sup +/
Lee, J.S.; Secrest, D.
1988-04-07
A new potential energy function is obtained for the ground electronic state of CH/sub 2//sup +/ through a Simons-Parr-Finlan (SPF) type expansion of an ab initio potential surface for this molecule. The SPF type potential is found to fit the a priori potential points extremely well and has reasonable physical properties along the vibrational coordinates of the molecule. The rotation-vibration states of this molecule are calculated for J = 0, 1, 2, and 3 by using this potential function. The calculations were carried out using a linear molecule Hamiltonian. Assignments have been made to each vibrational state. It is possible to identify the (1 1 0) state through the rotational structure of the molecule. This level was assigned to (0 4 0) previously. As in the previous calculations on this molecule, the Renner-Teller effect was neglected.
Palla, A; Tatalias, M; Straumann, D
2008-01-01
Healthy human subjects, when roll tilted in darkness, make systematic errors in estimating subjective visual vertical (SVV). Typically, roll tilt underestimation occurs at angles beyond 60 degrees (A-effect). At smaller tilt angles, overestimation may occur (E-effect). At approximately 135 degrees whole-body roll tilt, Kaptein and Van Gisbergen (2004, 2005) found an abrupt A/E transition, the exact location of which depended on the preceding rotation direction indicating hysteresis. Since this was observed using relatively fast roll velocity, it remains unclear whether the described hysteresis is dynamic or static. To clarify this uncertainty, we continuously rotated nine healthy subjects about the earth-horizontal naso-occipital axis, while they performed SVV adjustments every 2 s. Starting from the upright position, three full quasi-static constant velocity rotations (2 degrees/s) were completed in both directions (CW: clockwise; CCW: counterclockwise). SVV deviation from earth-verticality was plotted as a function of whole-body roll position. A bimodal Gaussian distribution function was fitted to SVV differences between CW and CCW rotations. A-effects (peaks at 88 degrees and 257 degrees chair position) at identical whole-body positions were larger after rotations from upside-down than after rotations from upright (average peak difference: 26 degrees). These results demonstrate static hysteresis for SVV estimation.
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
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.
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.
John R. Jones; Wayne D. Shepperd
1985-01-01
The rotation, in forestry, is the planned number of years between formation of a crop or stand and its final harvest at a specified stage of maturity (Ford-Robertson 1971). The rotation used for many species is the age of culmination of mean usable volume growth [net mean annual increment (MAI)]. At that age, usable volume divided by age reaches its highest level. That...
NASA Astrophysics Data System (ADS)
Xu, Jun; Dang, Chao; Kong, Fan
2017-10-01
This paper presents a new method for efficient structural reliability analysis. In this method, a rotational quasi-symmetric point method (RQ-SPM) is proposed for evaluating the fractional moments of the performance function. Then, the derivation of the performance function's probability density function (PDF) is carried out based on the maximum entropy method in which constraints are specified in terms of fractional moments. In this regard, the probability of failure can be obtained by a simple integral over the performance function's PDF. Six examples, including a finite element-based reliability analysis and a dynamic system with strong nonlinearity, are used to illustrate the efficacy of the proposed method. All the computed results are compared with those by Monte Carlo simulation (MCS). It is found that the proposed method can provide very accurate results with low computational effort.
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
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.
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.
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.
Tatalias, M; Bockisch, C J; Bertolini, G; Straumann, D; Palla, A
2011-03-01
Estimation of subjective whole-body tilt in stationary roll positions after rapid rotations shows hysteresis. We asked whether this phenomenon is also present during continuous quasi-static whole-body rotation and whether gravitational cues are a major contributing factor. Using a motorized turntable, 8 healthy subjects were rotated continuously about the earth-horizontal naso-occipital axis (earth-vertical roll plane) and the earth-vertical naso-occipital axis (earth-horizontal roll plane). In both planes, three full constant velocity rotations (2°/s) were completed in clockwise and counterclockwise directions (acceleration = 0.05°/s(2), velocity plateau reached after 40 s). Subjects adjusted a visual line along the perceived longitudinal body axis (pLBA) every 2 s. pLBA deviation from the longitudinal body axis was plotted as a function of whole-body roll position, and a sine function was fitted. At identical whole-body earth-vertical roll plane positions, pLBA differed depending on whether the position was reached by a rotation from upright or by passing through upside down. After the first 360° rotation, pLBA at upright whole-body position deviated significantly in the direction of rotation relative to pLBA prior to rotation initiation. This deviation remained unchanged after subsequent full rotations. In contrast, earth-horizontal roll plane rotations resulted in similar pLBA before and after each rotation cycle. We conclude that the deviation of pLBA in the direction of rotation during quasi-static earth-vertical roll plane rotations reflects static antihysteresis and might be a consequence of the known static hysteresis of ocular counterroll: a visual line that is perceived that earth-vertical is expected to be antihysteretic, if ocular torsion is hysteretic.
[Human tolerance to rotation at different levels of increased gravitation].
Genin, A M; Kotovskaia, A R; Galle, R R; Gavrilova, L N; Sarkisov, I Iu
1982-01-01
The effects of acceleration of different value (up to 2 g) on the level of motion sickness, vestibular and postural reactions to rotation were studied. The experiments were carried out in a centrifuge equipped with a cabin that could be mounted at a different distance from the axis of rotation. Three experimental runs were conducted with a rate of rotation of 15.3 and accelerations values of 1.09, 1.6 and 2.0 g. Vestibular stimulation was produced by head movements of a predetermined number. It was found that with increase in the acceleration value the level of motion sickness decreased and the nystagmic reaction and balance dysfunction enhanced.
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
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.
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).
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.
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
Paleocene sea level movements with a 430,000 year quasi-periodic cyclicity
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.
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.
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.
Benefits of atomic-level processing by quasi-ALE and ALD technique
NASA Astrophysics Data System (ADS)
Honda, M.; Katsunuma, T.; Tabata, M.; Tsuji, A.; Oishi, T.; Hisamatsu, T.; Ogawa, S.; Kihara, Y.
2017-06-01
A new technology has been developed using the atomic layer etching (ALE) and atomic layer deposition (ALD) concepts. It has been applied to self-aligned contacts (SAC) and patterning processes, for the sub 7 nm technology generation. In the SAC process, ultra-high selectivity of SiO2 etching towards SiN is required, for which we have developed quasi-ALE technique for SiO2 etching. We were able to significantly improve the trade-off between the etching ability of SiO2 on the micro slit portions and SiN selectivity. Quasi-ALE precisely controls the reaction layer thickness of the surface, by controlling the radical flux and ion flux independently, and hence enables etching at lower ion energies (E i < 250 eV). On the other hand, in the patterning processes, the shrinking of critical dimensions (CD) without loading is mandatory. Therefore, we developed a new process flow that combines ALD technique and etching. With this method, we were able to achieve CD shrinking at atomic-layer level precision for various patterns, without causing CD loading. In addition, we were also able to uniformly control the CD shrinkage amount across the whole wafer. This is because this technique takes advantage of the deposition step which is independent of the pattern density and the location on the wafer by self-limited reactions.
Variability of Rotational Temperatures from Different OH Rovibrational Levels
NASA Astrophysics Data System (ADS)
Vimal, D. V.; Slanger, T. G.
2011-12-01
TThe Meinel band emission lines from rovibrationally excited OH in its electronic ground state in the nightglow are widely used as a diagnostic tool to investigate key mesospheric variables such as temperature, tides, and gravity waves. The OH rotational temperature has been extensively studied to ascertain both long- and short-term variability in the upper atmosphere. Current controversy in the literature regarding the possible variability of temperatures deduced from different OH rovibrational levels limits our ability to compare data from different sources. Researchers tend to use a monitoring vibrational level for OH Meinel bands that is most convenient for their instrument. Background sky spectra captured by astronomical instruments provide detailed records of optical emissions in the upper atmosphere. For this study we utilized existing sky spectra from the Keck telescopes in Mauna Kea and the Very Large Telescope in Chile for the OH Meinel bands bound by the extremes (υ = 3, 8). We compared these results with the temperatures deduced from the O2 0-1 Atmospheric band at 865 nm. This latter emission, emanating from a long-lived species, should represent the true kinetic temperature at the altitude of emission and therefore puts a cap on how high the temperature difference can be between the nominal OH altitude (87 km) and the 95-km altitude of the O2 emission. We present the results of our analysis and discuss the implications for mesospheric temperature retrievals from OH emissions. This work was supported by NSF grant ATM-0924781 from NSF CEDAR.
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.
Diode-pumped quasi-three-level 456-nm Nd:GdVO{sub 4} laser
Zavartsev, Yu D; Zagumennyi, A I; Kutovoi, S A; Mikhailov, V A; Podreshetnikov, V V; Sirotkin, A A; Shcherbakov, Ivan A; Zerrouk, F
2003-07-31
A diode-pumped quasi-three-level Nd:GdVO{sub 4} laser emitting at a wavelength of 912 nm corresponding to the {sup 4}F{sub 3/2} - {sup 4}I{sub 9/2} transition of the neodymium ion and at the second-harmonic linewidth of 456 nm after intracavity frequency doubling in a KNbO{sub 3} crystal is studied. The maximum output power at the fundamental frequency was 2.96 W and the conversion efficiency amounted to 48 %. The second-harmonic output power achieved 220 mW for the conversion efficiency of 15 %. (special issue devoted to the memory of academician a m prokhorov)
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.
Quasi-Fermi level splitting and sub-bandgap absorptivity from semiconductor photoluminescence
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
NASA Technical Reports Server (NTRS)
Yao, M.-S.
1980-01-01
A study of the maintenance of the quasistationary waves forced by topography using a truncated two-level quasigeostrophic spectral model in a zonal channel on a beta-plane is presented. The model's motion contains wavenumbers 0, n, and 2n in the zonal direction, where n is the lowest eddy wavenumber and also the wavenumber of the topography. The study covered the two cases defined by n=2 and n=3; the spectral mode was integrated by initially perturbing the stationary solution of the equations governing the spectral coefficients, and a detailed energetics study was made of the quasiequilibrium state to study the maintenance of the quasistationary waves. The energy conversions required for maintaining these waves when n=3 imply that they are generated mainly by baroclinic stability of the forced waves; this type of baroclinic wave tends to become stationary to draw efficiently on the available energy of the forced wave.
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.
NASA Astrophysics Data System (ADS)
Aeberhard, Urs
2017-04-01
The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions [1]. So far, the theory has been verified for a wide range of devices and material systems and forms the basis of a growing number of luminesecence imaging techniques used in the characterization of photovoltaic materials, cells and modules [2-5]. However, there are also some examples where the theory fails, such as in the case of amorphous silicon. In our contribution, we critically assess the assumptions made in the derivation of the theory and compare its predictions with rigorous formal relations as well as numerical computations in the framework of a comprehensive quantum-kinetic theory of photovoltaics [6] as applied to ultra-thin absorber architectures [7]. One of the main applications of the photovoltaic reciprocity relation is the determination of quasi-Fermi level splittings (QFLS) in solar cells from the measurement of luminescence. In nanostructure-based photovoltaic architectures, the determination of QFLS is challenging, but instrumental to assess the performance potential of the concepts. Here, we use our quasi-Fermi level-free theory to investigate existence and size of QFLS in quantum well and quantum dot solar cells. [1] Uwe Rau. Reciprocity relation between photovoltaic quantum efficiency and electrolumines- cent emission of solar cells. Phys. Rev. B, 76(8):085303, 2007. [2] Thomas Kirchartz and Uwe Rau. Electroluminescence analysis of high efficiency cu(in,ga)se2 solar cells. J. Appl. Phys., 102(10), 2007. [3] Thomas Kirchartz, Uwe Rau, Martin Hermle, Andreas W. Bett, Anke Helbig, and Jrgen H. Werner. Internal voltages in GaInP-GaInAs-Ge multijunction solar cells determined by electro- luminescence measurements. Appl. Phys. Lett., 92(12), 2008. [4] Thomas Kirchartz, Anke Helbig, Wilfried Reetz, Michael Reuter, Jürgen H. Werner, and
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.
Electric-field-induced destruction of quasi-Landau levels in bilayer graphene nanoribbons.
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.
Fluctuations of the Caspian Sea level in the quasi-two-year and 11-year cycles of solar activity
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.
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
Sweeney, Ryan Myles; Choi, W.; La Haye, R. J.; Mao, S.; Olofsson, K. E. J.; Volpe, F. A.
2016-11-01
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, ${{\\beta}_{\\text{N}}}$ , is observed to peak at an intermediate value, and decrease for high values. The decrease is attributed to the correlation between ${{\\beta}_{\\text{N}}}$ 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
Sweeney, Ryan Myles; Choi, W.; La Haye, R. J.; ...
2016-11-01
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 tomore » $${{l}_{i}}/{{q}_{95}}$$ 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, $${{\\beta}_{\\text{N}}}$$ , is observed to peak at an intermediate value, and decrease for high values. The decrease is attributed to the correlation between $${{\\beta}_{\\text{N}}}$$ 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
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.
Papalia, Rocco; Del Buono, Angelo; Leonardi, Francesco; Osti, Leonardo; Maffulli, Nicola; Denaro, Vincenzo
2011-05-01
To determine the plasma levels of nonprotein nitrogen (NPN) and creatinine in healthy patients with rotator cuff tears. The study included 400 subjects. The study group included 200 patients (93 men and 107 women; mean age, 56.8 years; range, 23-81 years) who underwent arthroscopic repair of a rotator cuff tear from 2004 to 2007. The control group included 200 patients (93 men and 107 women; mean age, 53.9 years; range, 20-81 years) who underwent arthroscopy for management of a meniscal tear, with or without articular cartilage damage, in the same period. The 2 groups were frequency-matched by age and sex. Measurement of plasma levels of NPN and creatinine were performed in all patients. Patients with rotator cuff tears showed higher plasma NPN levels within the normal range (P = 0.035) than patients with knee disorders (control group). Creatinine levels were comparable (P = 0.66) in both groups. There appears to be an association between plasma NPN levels and rotator cuff tears. On the basis of our findings, plasma NPN could be involved in the pathogenesis of rotator cuff tears, although we advocate further research to draw more definitive conclusions.
Habacha, Hamdi; Lejeune-Poutrain, Laure; Margas, Nicolas; Molinaro, Corinne
2014-10-01
A recent set of studies has investigated the selective effects of particular physical activities that require full-body rotations, such as gymnastics and wrestling (Moreau, Clerc, Mansy-Dannay, & Guerrien, 2012; Steggemann, Engbert, & Weigelt, 2011), and demonstrated that practicing these activities imparts a clear advantage in in-plane body rotation performance. Other athletes, such as handball and soccer players, whose activities do require body rotations may have more experience with in-depth rotations. The present study examined the effect of two components that are differently solicited in sport practices on the mental rotation ability: the rotation axis (in-plane, in-depth) and the predominantly used limb (arms, legs). Handball players, soccer players, and gymnasts were asked to rotate handball and soccer strike images mentally, which were presented in different in-plane and in-depth orientations. The results revealed that handball and soccer players performed the in-depth rotations faster than in-plane rotations; however, the two rotation axes did not differ in gymnasts. In addition, soccer players performed the mental rotations of handball strike images slower. Our findings suggest that the development of mental rotation tasks that involve the major components of a physical activity allows and is necessary for specifying the links between this activity and the mental rotation performance. Copyright © 2014 Elsevier B.V. All rights reserved.
Rotational level involvement in the T1-->S0 intersystem crossing transition in thiophosgene.
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.
Rotating shift-related changes in hormone levels in intensive care unit nurses.
Korompeli, Anna; Sourtzi, Panayota; Tzavara, Chara; Velonakis, Emmanouel
2009-06-01
This paper is a report of a study to investigate if an irregular rotating shift system, including night shifts, can cause changes to the secretion of hormones in nurses. In 2006, 32 healthy intensive care unit nurses completed the Standard Shiftwork Index (SSI) and blood samples were collected from each participant at the beginning and end of each shift. Change in hormone levels between the beginning and end of morning shifts were examined and compared between nurses on morning only and rotating shifts. Correlations between change in hormone concentrations and scores from the SSI are presented. The mean reduction of cortisol level between the two measurements was statistically significantly greater for the 'rotating' than 'morning' shift group (P = 0.032). There were no statistically significant differences between the two groups in overall mean change from the first to the second measurement of prolactin, triiodothyronine and thyroid-stimulating hormone. Levels of thyroxine increased statistically significantly in the 'rotating' group (P = 0.049) but not in the 'morning' group. The morningness scale score was greater for the 'rotating' group, while greater job satisfaction levels were found in the 'morning' group. Statistically significant correlations were found between thyroid-stimulating hormone, triiodothyronine, thyroxine and prolactin changes and specific scales of the SSI questionnaire. Ergonomic shift schedules sympathetic to the body clock and nurses' preferences should be adopted to mitigate the adverse effects on health.
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.
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.
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.
Comparison of alertness levels in ship crew. An experiment on rotating versus fixed watch schedules.
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.
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.
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…
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.
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.
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.
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.
The response of ceramic powders to high-level quasi-isentropic dynamic loads.
Lawrence, Raymond Jeffery Jr.; Grady, Dennis Edward; Hall, Charles Ainsley
2003-07-01
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., Al{sub 2}O{sub 3}, WC, ZrO{sub 2} - 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/{alpha} 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, p{sub s}. With adequate sample thicknesses, the planned velocity measurements differentiate among the various assumptions for p{sub s}.
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.
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.
Two-stage double-level rotational osteotomy in the treatment of congenital radioulnar synostosis.
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.
Ab initio potential energy surface and vibration-rotation energy levels of beryllium monohydroxide.
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. © 2016 Wiley Periodicals, Inc.
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.
Rotational stress-induced increase in epinephrine levels delays cutaneous wound healing in mice.
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.
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…
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…
Quasi-three-level orthogonally polarized cw dual-wavelength operation in Nd:LiYF4
NASA Astrophysics Data System (ADS)
Zhang, Jing; Xia, Jing; Fu, Xihong; Zhai, Pei
2017-05-01
A diode-end-pumped quasi-three-level orthogonally polarized continuous-wave (cw) dual-wavelength Nd:LiYF4 (Nd:YLF) laser that generates simultaneous laser at the wavelengths 903 nm and 908 nm was demonstrated. Two types of cavity configurations were studied to support the stable dual-wavelength operation of the laser. A polarization beam splitter (PBS) was placed in the first type of cavity to split the beams polarizing in two orthogonal directions. At an absorbed pump power of 21.4 W, the cw output power obtained at 903 nm in π-polarization and 908 nm in σ-polarization is 0.43 W and 3.31 W, respectively. Furthermore, in order to balance the gain-to-loss, an uncoated glass plane was inserted in the second type of cavity. By adjusting the inclination of the glass plane relative to the optical axis of the resonator, we realized the stable simultaneous dual-wavelength operation. The cw output powers of 1.82 W at 903 nm and of 2.92 W at 908 nm were obtained.
Cuff, Derek J; O'Brien, Kathleen C; Pupello, Derek R; Santoni, Brandon G
2016-07-01
To evaluate multiple preoperative and operative factors that may be predictive of and correlate with acute postoperative pain levels after arthroscopic rotator cuff repair. One hundred eighty-one patients underwent arthroscopic rotator cuff surgery along with subacromial decompression and met the inclusion criteria for this study. Postoperative visual analog scale (VAS) scores were obtained on postoperative days 1, 7, and 90. Multivariate linear regression analysis was used to correlate postoperative VAS scores with multiple independent factors, including preoperative subjective pain tolerance, preoperative VAS score, preoperative narcotic use, sex, smoking status, number of suture anchors used, tear size, single- or double-row repair, and patient age. Preoperative subjective pain tolerance, notably those patients rating themselves as having an extremely high pain tolerance, was the most significant predictor of high VAS pain scores on both postoperative day 1 (P = .0001) and postoperative day 7 (P < .0001). Preoperative narcotic use was also significantly predictive (P = .010) of high pain scores on postoperative day 1 and day 7 (P = .019), along with nonsmokers (P = .008) and younger patients (P = .006) being predictive on day 7. There were no patient factors that were predictive of VAS scores 3 months postoperatively (P = .567). Preoperative subjective pain tolerance, notably those patients rating themselves as having an extremely high pain tolerance, was the strongest factor predicting high acute pain levels after arthroscopic rotator cuff surgery. Preoperative narcotic use, smokers, and younger patients were also predictive of higher pain levels during the first postoperative week. Level IV, prognostic case series. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
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.
Tunneling splitting of energy levels and rotational constants in the vinyl radical C2H3.
Mil'nikov, Gennady V; Ishida, Toshimasa; Nakamura, Hiroki
2006-04-27
The instanton theory newly implemented by two of the authors (G.V.M. and H.N.) is applied to hydrogen tunneling transfer in a vinyl radical. The converged instanton trajectory is found on the CCSD(T)/aug-cc-pVTZ level of an ab initio potential energy surface. The calculated ground-state energy splitting agrees with the recent high-resolution experimental data within 3% of discrepancy. The semiclassical wave function is used to estimate the splitting of the principal rotational constants of the radical.
Zeeman-tuned rotational level-crossing spectroscopy in a diatomic free radical.
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.
Hernigou, Philippe; Merouse, Guillaume; Duffiet, Pascal; Chevalier, Nathalie; Rouard, Helene
2015-06-01
While the use of bone marrow concentrate (BMC) has been described in the treatment of rotator cuff tears, the impact of a rotator cuff injury on the mesenchymal stem cells (MSCs) content present in the human shoulder has not been determined, especially with regard to changes in the levels of MSCs at the tendon-bone interface. With the hypothesis that there was a decreased level of MSCs at the tendon-bone interface tuberosity in patients with rotator cuff tear, we assessed the level of MSCs in the tuberosity of the shoulder of patients undergoing a rotator cuff repair. We analysed the data of 125 patients with symptomatic rotator cuff tears and of 75 control patients without rotator cuff injury. We recorded the following data: size of tear, number of torn tendons, aetiology of the tear, lag time between onset of shoulder symptoms/injury and repair, and also fatty infiltration of muscles. Mesenchymal stem cell content at the tendon-bone interface tuberosity was evaluated by bone marrow aspiration collected in the humeral tuberosities of patients at the beginning of surgery. A significant reduction in MSC content (from moderate, 30-50 %, to severe >70 %) at the tendon-bone interface tuberosity relative to the MSC content of the control was observed in all rotator cuff repair study patients. Severity of the decrease was statistically correlated to a number of factors, including the delay between onset of symptoms and surgery, number of involved tendons, fatty infiltration stage and increasing patient age. This study demonstrates that the level of MSCs present in the greater tuberosity of patients with a rotator cuff tear decreases as a function of a number of clinical factors, including lag time from tear onset to treatment, tear size, number of tears and stage of fatty infiltration, among others. This information may help the practices in using biologic augmentation of a rotator cuff repair.
NASA Astrophysics Data System (ADS)
Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter; Andersen, Peter Eskil; Petersen, Paul Michael; Sumpf, Bernd; Erbert, Götz; Pedersen, Christian
2010-12-01
Using a tunable external cavity tapered diode laser (ECDL) pumped quasi-three-level Nd:YAG laser, a fivefold reduction in threshold and twofold increase in slope efficiency is demonstrated when compared to a traditional broad area diode laser pump source. A TEM 00 power of 800 mW with 65% slope efficiency is obtained, the highest reported TEM 00 power from any 946 nm Nd:YAG laser pumped by a single emitter diode laser pump source. A quantum efficiency of 0.85 has been estimated from experimental data using a simple quasi-three-level model. The reported value is in good agreement with published values, suggesting that the model is adequate. Improvement of the 946 nm laser due to the ECDL's narrow spectrum proves to be less significant when compared to its spatial quality, inferring a broad spectrum tapered diode laser pump source may be most practical. Experimental confirmation of such setup is given.
ERIC Educational Resources Information Center
Beste, Christian; Heil, Martin; Konrad, Carsten
2010-01-01
The cognitive process of imaging an object turning around is called mental rotation. Many studies have been put forward analyzing mental rotation by means of event-related potentials (ERPs). Event-related potentials (ERPs) were measured during mental rotation of characters in a sample (N = 82) with a sufficient size to obtain even small effects. A…
Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues
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.
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.
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.
Freitag, I.; Henking, R.; Tuennermann, A.; Welling, H.
1995-12-01
Efficient room-temperature operation of a diode-pumped Nd:YAG laser is demonstrated for the quasi-three-level transition at 946 nm. Continuous-wave output powers of more than 800 mW cw in single-frequency operation are generated by application of a composite-cavity nonplanar ring laser. High amplitude and frequency stability of the emitted radiation is observed. {copyright} {ital 1995 Optical Society of America.}
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.
Ab initio potential energy surface and vibration-rotation energy levels of sulfur dioxide.
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. © 2017 Wiley Periodicals, Inc.
Sträter, H. Brüggemann, R.; Bauer, G. H.; Siol, S.; Klein, A.; Jaegermann, W.
2013-12-21
We have studied chalcocite (Cu{sub 2}S) layers prepared by physical vapor deposition with varying deposition parameters by calibrated spectral photoluminescence (PL) and by confocal PL with lateral resolution of Δ x≈0.9 μm. Calibrated PL experiments as a function of temperature T and excitation fluxes were performed to obtain the absolute PL-yield and to calculate the splitting of the quasi-Fermi levels (QFLs) μ=E{sub f,n}−E{sub f,p} at an excitation flux equivalent to the AM 1.5 spectrum and the absorption coefficient α(ℏω), both in the temperature range of 20 K≤T≤400 K. The PL-spectra reveal two peaks at E{sub #1}=1.17 eV and E{sub #2}=1.3 eV. The samples show a QFL-splitting of μ>700 meV associated with a pseudo band gap of E{sub g}=1.25 eV. The high-energy peak shows an unexpected temperature behavior, namely, an increase of PL-yield with rising temperature at variance with the behavior of QFL-splitting that decreases with rising T. Our observations indicate that, contrary to common believe, it is not the PL-yield, but rather the QFL-splitting that is the comprehensive indicator of the quality of the excited state in an illuminated semiconductor. A further examination of the lateral variation of opto-electronic properties by confocal PL and the surface contour shows no detectable correlation between Cu{sub 2}S grains/grain boundaries and the PL-yield or QFL-splitting.
Mannan, A; Smith, T O
2016-03-01
Implant malposition in total knee arthroplasty (TKA) often results in unsatisfactory outcomes. Rotational malalignment leads to impaired patellar tracking, stability and joint biomechanics. Patient-specific instrumentation aims to improve three-dimensional implant positioning while reducing overall costs of instrumentation. A PRISMA compliant search of all relevant literature between 2000 and 2014 was performed. The primary outcome of interest was deviation from a neutral femoral and tibial axial alignment of patient-specific instrumentation (PSI) vs conventional instrumentation. Femoral rotation was measured with reference to the transepicondylar axis. Tibial rotation was reported with reference to the anterior tibial tuberosity and a "best fit" with the anterior tibial cortex. Six randomised studies met the inclusion criteria reporting on a total of 444 knees. Computed tomography (CT) based PSI systems were used exclusively in three studies, and two further studies in association with magnetic resonance imaging (MRI). MRI was used exclusively in one study. Mean femoral rotation in the conventional group was: -1.7 to 1.6° (vs -1.7 to 1° in the PSI group). Meta-analysis demonstrated a significant treatment effect favouring PSI with increased accuracy in "three-degree outliers" with femoral rotation: Z=2.07, P=0.04. A single study reported tibial rotational outcomes with no significant difference demonstrated in conventional instrumentation vs PSI. This Level 1 meta-analysis demonstrates favourable femoral rotational alignment outcomes in PSI knee arthroplasty. Only limited data is available for tibial rotational outcomes. Further studies with standardised "gold-standard" measurement criteria are required to clarify tibial rotational outcomes in PSI TKA. 1. Copyright © 2015 Elsevier B.V. All rights reserved.
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.
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.
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.
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.
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 0
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.
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.
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.
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].
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.
Kahol, Kanav; Huston, Carrie; Hamann, Jessica; Ferrara, John J
2011-03-01
Health care continues to expand in scope and in complexity. In this changing environment, residents are challenged with understanding its intricacies and the impact it will have on their professional activities and careers. Embedding each of the competency elements in residents in a meaningful way remains a challenge for many surgery residency program directors. We established a nonclinical rotation to provide surgery postgraduate year-1 (PGY-1) residents with a structured, multifaceted, largely self-directed curriculum into which each of the 6 core competencies are woven. Posttesting strategies were established for most curricular experiences to ensure to the greatest possible extent that each resident will have achieved an acceptable level of understanding of each of the competency areas before being given credit for the rotation. By uniformly exceeding satisfactory scores on respective objective analyses, residents demonstrated an increased (at least short-term) understanding of each of the assessed competency areas. Our project sought to address a prior lack of opportunity for our residents to develop a sound foundation for our residents in systems-based practice. Our new rotation addresses systems-based practice in several different learning environments, including emergency medical service ride-along, sentinel event participation, and hospice visits. Several research projects have enhanced the overall learning program. Our experience shows that a rotation dedicated to competency training can provide an innovative and engaging means of teaching residents the value of each element.
Kahol, Kanav; Huston, Carrie; Hamann, Jessica; Ferrara, John J
2011-01-01
Background Health care continues to expand in scope and in complexity. In this changing environment, residents are challenged with understanding its intricacies and the impact it will have on their professional activities and careers. Aim Embedding each of the competency elements in residents in a meaningful way remains a challenge for many surgery residency program directors. Methods We established a nonclinical rotation to provide surgery postgraduate year-1 (PGY-1) residents with a structured, multifaceted, largely self-directed curriculum into which each of the 6 core competencies are woven. Posttesting strategies were established for most curricular experiences to ensure to the greatest possible extent that each resident will have achieved an acceptable level of understanding of each of the competency areas before being given credit for the rotation. Results By uniformly exceeding satisfactory scores on respective objective analyses, residents demonstrated an increased (at least short-term) understanding of each of the assessed competency areas. Conclusion Our project sought to address a prior lack of opportunity for our residents to develop a sound foundation for our residents in systems-based practice. Our new rotation addresses systems-based practice in several different learning environments, including emergency medical service ride-along, sentinel event participation, and hospice visits. Several research projects have enhanced the overall learning program. Our experience shows that a rotation dedicated to competency training can provide an innovative and engaging means of teaching residents the value of each element. PMID:22379529
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.
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.
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.
Courtens, Emilie N P; Boon, Nico; De Clippeleir, Haydée; Berckmoes, Karla; Mosquera, Mariela; Seuntjens, Dries; Vlaeminck, Siegfried E
2014-03-01
With oxygen supply playing a crucial role in an oxygen-limited autotrophic nitrification/denitrification (OLAND) rotating biological contactor (RBC), its controlling factors were investigated in this study. Disc rotation speeds (1.8 and 3.6rpm) showed no influence on the process performance of a lab-scale RBC, although abiotic experiments showed a significant effect on the oxygenation capacity. Estimations of the biological oxygen uptake rate revealed that 85-89% of the oxygen was absorbed by the microorganisms during the air exposure of the discs. Indeed, increasing the disc immersion (50 to 75-80%) could significantly suppress undesired nitratation, on the short and long term. The presented results demonstrated that nitratation could be controlled by the immersion level and revealed that oxygen control in an OLAND RBC should be predominantly based on the atmospheric exposure percentage of the discs. Copyright © 2013 Elsevier Ltd. All rights reserved.
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.
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
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.
Fénelon, Karine; Lamboley, Cédric R.H.; Carrier, Nicole
2012-01-01
Experiments were performed to characterize the properties of the intrinsic Ca2+ buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([CaT]SR and [Ca2+]SR) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca2+ indicator). Results indicate SR Ca2+ 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 Ca2+. Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca2+]SR and [CaT]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 Ca2+ permeability of the SR, namely d[CaT]SR/dt ÷ [Ca2+]SR (denoted release permeability), in experiments in which only [CaT]SR or [Ca2+]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 Ca2+ release of 2.3 SR Ca2+ release channels neighboring each channel activated by its associated voltage sensor. Release permeability at −60 mV increases as [CaT]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 [Ca2+]SR inhibits release when [CaT]SR declines to a low level
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
Thompson, T.A.; Baedke, S.J.
1996-01-01
Strandplains of arcuate beach ridges are common in coastal embayments in parts of the Great Lakes. Similarities in beach-ridge development and geomorphology are recognizable in many of the embayments in the Lake Michigan basin despite differences in size and shape, available sediment type and supply, predepositional slope and topography, and hydrographic regime between the embayments. These similarities are primarily a product of three scales of quasiperiodic lake-level variation ranging in time from 30 to 600 years and in water level change from 0.5 to 3.7 m. The interaction of these three lake-level variations can be represented on a Curray (1964) diagram (rate of water level change versus rate of sediment supply). The position of any shoreline on the diagram and the type of behavior the shoreline is experiencing is a product of the interaction of the three variations. Two large Strandplains of late Holocene beach ridges occur at opposite ends of Lake Michigan (Toleston Beach and Thompson embayment). The two areas exhibit similar patterns of beach-ridge development for the past 2600 calendar years. That is, both areas form beach ridges about every 30 years. Groups of 4 to 6 beach ridges reflect a longer-term lake-level variation of about 150 years. Only during the largest variation of about 600 years in duration do the two areas differ. The rise to the 1700 cal yr B.P. high caused the erosion of beach ridges back to 2800 cal yrs B.P. in northern Lake Michigan. In southern Lake Michigan, no erosion occurred during this lake level high. Differences in shoreline development between the two areas are related to the rate of sediment supply to the shorelines. As the sediment sink for the southern half of Lake Michigan, the southern strandplain received a greater sediment flux than the northern strandplain during the latter part of the late Holocene and produced a continuous record of beach-ridge development. ?? 1995 Elsevier Science B.V. All rights reserved.
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.
Smith, Lee; Kipps, Courtney; Aggio, Daniel; Fox, Paul; Robinson, Nigel; Trend, Verena; Munnery, Suzie; Kelly, Barry; Hamer, Mark
2014-01-01
Introduction Physical activity is essential for every facet of children's health. However, physical activity levels in British children are low. The school environment is a promising setting to increase children's physical activity but limited empirical evidence exists on how a change in the outdoor physical school environment influences physical activity behaviour. The London Borough of Camden is redesigning seven existing school playgrounds to engage children to become more physically active. The primary aim of this project is to evaluate the impact of the redesigned playgrounds on children's physical activity, well-being and physical function/fitness. Method and analysis This project will use a longitudinal quasi-experimental design. Seven experimental schools and one control school will take part. One baseline data collection session and two follow-ups will be carried out. Between baseline and follow-up, the experimental school playgrounds will be redesigned. At baseline, a series of fitness tests, anthropometric and questionnaire measurements, and 7-day objective physical activity monitoring (Actigraph accelerometer) will be carried out on children (aged 5–16 years). This will be repeated at follow-up. Changes in overall physical activity levels and levels during different times of the day (eg, school breaks) will be examined. Multilevel regression modelling will be used to analyse the data. Ethics and dissemination The results of this study will be disseminated through peer-review publications and scientific presentations. Ethical approval was obtained through the University College London Research Ethics Committee (Reference number: 4400/002). PMID:25232566
Smith, Lee; Kipps, Courtney; Aggio, Daniel; Fox, Paul; Robinson, Nigel; Trend, Verena; Munnery, Suzie; Kelly, Barry; Hamer, Mark
2014-01-01
Physical activity is essential for every facet of children's health. However, physical activity levels in British children are low. The school environment is a promising setting to increase children's physical activity but limited empirical evidence exists on how a change in the outdoor physical school environment influences physical activity behaviour. The London Borough of Camden is redesigning seven existing school playgrounds to engage children to become more physically active. The primary aim of this project is to evaluate the impact of the redesigned playgrounds on children's physical activity, well-being and physical function/fitness. This project will use a longitudinal quasi-experimental design. Seven experimental schools and one control school will take part. One baseline data collection session and two follow-ups will be carried out. Between baseline and follow-up, the experimental school playgrounds will be redesigned. At baseline, a series of fitness tests, anthropometric and questionnaire measurements, and 7-day objective physical activity monitoring (Actigraph accelerometer) will be carried out on children (aged 5–16 years). This will be repeated at follow-up. Changes in overall physical activity levels and levels during different times of the day (eg, school breaks) will be examined. Multilevel regression modelling will be used to analyse the data. The results of this study will be disseminated through peer-review publications and scientific presentations. Ethical approval was obtained through the University College London Research Ethics Committee (Reference number: 4400/002).
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.
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.
2011-01-01
The pedicle is a power nucleus of the vertebra and offers a secure grip of all 3 columns. Pedicle screw instrumentation has advantages of rigid fixation with improved three-dimensional (3D) correction and it is accepted as a reliable method with a high margin of safety. Accurate placement of the pedicle screws is important to reduce possible irreversible complications. Many methods of screw insertion have been reported. The author has been using the K-wire method coupled with the intraoperative single posteroanterior and lateral radiographs, which is the most safe, accurate and fast method. Identification of the curve patterns and determining the fusion levels are very important. The ideal classification of adolescent idiopathic scoliosis should address the all patterns, predict the extent of accurate fusion and have good inter/intraobserver reliability. My classification system matches with the ideal classification system, and it is simple and easy to learn; and my classification system has only 4 structural curve patterns and each curve has 2 types. Scoliosis is a 3D deformity; the coronal and sagittal curves can be corrected with rod rotation, and rotational deformity has to be corrected with direct vertebral rotation (DVR). Rod derotation and DVR are true methods of 3D deformity correction with shorter fusion and improved correction of both the fused and unfused curves, and this is accomplished using pedicle screw fixation. The direction of DVR is very important and it should be opposite to the direction of the rotational deformity of the vertebra. A rigid rod has to be used to prevent rod bend-out during the derotation and DVR. PMID:21629468
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.
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.
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.
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.
Ab initio potential energy surface and vibration-rotation energy levels of silicon dicarbide, SiC2.
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. © 2016 Wiley Periodicals, Inc.
Role of serum fibrinogen levels in patients with rotator cuff tears.
Longo, Umile Giuseppe; Petrillo, Stefano; Berton, Alessandra; Spiezia, Filippo; Loppini, Mattia; Maffulli, Nicola; Denaro, Vincenzo
2014-01-01
Although rotator cuff (RC) tendinopathy is a frequent pathology of the shoulder, the real understanding of its aetiopathogenesis is still unclear. Several studies showed that RC tendinopathy is more frequent in patients with hyperglycemia, diabetes, obesity, or metabolic syndrome. This paper aims to evaluate the serum concentration of fibrinogen in patients with RC tears. Metabolic disorders have been related to high concentration of serum fibrinogen and the activity of fibrinogen has been proven to be crucial in the development of microvascular damage. Thus, it may produce progression of RC degeneration by reducing the vascular supply of tendons. We report the results of a cross-sectional frequency-matched case-control study comparing the serum concentration of fibrinogen of patients with RC tears with that of a control group of patients without history of RC tears who underwent arthroscopic meniscectomy. We choose to enrol in the control group patients with pathology of the lower limb with a likely mechanic, not metabolic, cause, different from tendon pathology. We found no statistically significant differences in serum concentration of fibrinogen when comparing patients with RC tears and patients who underwent arthroscopic meniscectomy (P = 0.5). Further studies are necessary to clarify the role of fibrinogen in RC disease.
NASA Technical Reports Server (NTRS)
Mcdermid, I. S.; Laudenslager, J. B.
1982-01-01
A narrow-bandwidth pulsed dye laser was used to excite OH X 2Pi i radicals to the A 2Sigma(+) state by pumping in the (0, 0) vibrational band around 308 nm. The radiative lifetimes of specific (K-prime, J-prime) rotational levels in v-prime = 0 were measured at low pressures (not greater than 1 mtorr), which yielded a mean lifetime of 0.71 + or - 0.009 microsec (2 sigma). Electronic quenching rate constants for N2, O2, H2O, and H2 were measured for a range of initially excited rotational levels. A strong dependence of this rate constant on the initially excited rotational level was found for N2, and less markedly for O2, with the rate constant tending to increase for the lowest rotational levels K-prime not greater than 3. The implications of these results for the laser-induced fluorescence detection of atmospheric OH are discussed.
Niu, Shu-Fen; Chung, Min-Huey; Chen, Chiung-Hua; Hegney, Desley; O'Brien, Anthony; Chou, Kuei-Ru
2011-03-01
Disrupted circadian rhythm, especially working night duty together with irregular sleep patterns, sleep deprivation, and fatigue, creates an occupational health risk associated with diminished vigilance and work performance. This study reviewed the effect of shift rotations on employee cortisol profile, sleep quality, fatigue, and attention level. Researchers conducted a systematic review of relevant articles published between 1996 and 2008 that were listed on the following databases: SCOPUS, OVID, Blackwell Science, EBSCO Host, PsycINFO, Cochrane Controlled Trials Register, and CEPS. A total of 28 articles were included in the review. Previous research into the effects of shift work on cortisol profiles, sleep quality, fatigue, and attention used data assessed at evidence Levels II to IV. Our systematic review confirmed a conflict between sleep-wake cycle and light-dark cycle in night work. Consequences of circadian rhythm disturbance include disruption of sleep, decreased vigilance, general feeling of malaise, and decreased mental efficiency. Shift workers who sleep during the day (day sleepers) experience cortisol secretion increases, which diminish the healing power of sleep and enjoy 1 to 4 hours less sleep on average than night sleepers. Sleep debt accumulation results in chronic fatigue. Prolonged fatigue and inadequate recovery result in decreased work performance and more incidents. Rotation from day shift to night shift and its effect on shift workers was a special focus of the articles retained for review. Disturbed circadian rhythm in humans has been associated with a variety of mental and physical disorders and may negatively impact on work safety, performance, and productivity.
NASA Astrophysics Data System (ADS)
Polyansky, Oleg L.; Ovsyannikov, Roman I.; Kyuberis, Aleksandra A.; Lodi, Lorenzo; Tennyson, Jonathan; Yachmenev, Andrey; Yurchenko, Sergei N.; Zobov, Nikolai F.
2016-09-01
An ab initio potential energy surface (PES) for gas-phase ammonia NH3 has been computed using the methodology pioneered for water (Polyansky et al., 2013). Multireference configuration interaction calculations are performed at about 50 000 points using the aug-cc-pCVQZ and aug-cc-pCV5Z basis sets and basis set extrapolation. Relativistic and adiabatic surfaces are also computed. The points are fitted to a suitable analytical form, producing the most accurate ab initio PES for this molecule available. The rotation-vibration energy levels are computed using nuclear motion program TROVE in both linearised and curvilinear coordinates. Better convergence is obtained using curvilinear coordinates. Our results are used to assign the visible spectrum of 14NH3 recorded by Coy and Lehmann (1986). Rotation-vibration energy levels for the isotopologues NH2D, NHD2, ND3 and 15NH3 are also given. An ab initio value for the dissociation energy D0 of 14NH3 is also presented.
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.
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.
Ross, Stephen C; Yamada, Koichi M T
2007-11-21
A surprisingly rich variety of phenomena are revealed in the energy level correlation between the limits of a tunnelling doubled harmonic oscillator and a bi-rotor. Some levels are found to have their vibrational quantum number "promoted" upon removal of the barrier to rotation, other levels, which we dub "invariant", are found to be completely independent of the barrier, while yet other levels exhibit a smooth transition between these limits. The general nature of these features can be understood in terms of the different degeneracies of the limiting cases. The elucidation of these effects aids the understanding of the rotational-vibrational energy levels of molecules having two internal rotor moieties.
NASA Astrophysics Data System (ADS)
Császár, Attila G.; Furtenbacher, T.; Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.
2014-06-01
The results of an IUPAC Task Group formed in 2004 on "A Database of Water Transitions from Experiment and Theory" (Project No. 2004-035-1-100) are presented. Energy levels and recommended labels involving exact and approximate quantum numbers for the main isotopologues of water in the gas phase, H216O, H218O, H217O, HD16O, HD18O, HD17O, D216O, D218O, and D217O, are determined from measured transition wavenumbers. The transition wavenumbers and energy levels are validated using the MARVEL (measured active rotational-vibrational energy levels) approach and first-principles nuclear motion computations. The extensive data, e.g., more than 200,000 transitions have been handled for H216O, including lines and levels that are required for analysis and synthesis of spectra, thermochemical applications, the construction of theoretical models, and the removal of spectral contamination by ubiquitous water lines. These datasets can also be used to assess where measurements are lacking for each isotopologue and to provide accurate frequencies for many yet-to-be measured transitions. The lack of high-quality frequency calibration standards in the near infrared is identified as an issue that has hindered the determination of high-accuracy energy levels at higher frequencies. The generation of spectra using the MARVEL energy levels combined with transition intensities computed using high accuracy ab initio dipole moment surfaces are discussed.
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
NASA Astrophysics Data System (ADS)
Zeng, H. S.; Tang, N.; Zheng, Y. P.; Xu, T. T.
2012-10-01
By use of the recently presented two measures, the indivisibility and the backflow of information, we study the non-Markovianity of the dynamics for a two-level system interacting with a zero-temperature structured environment without using rotating wave approximation (RWA). In the limit of weak coupling between the system and its reservoir, and by expanding the time-convolutionless (TCL) generator to the forth order with respect to the coupling strength, the time-local non-Markovian master equation for the reduced state of the system is derived. Under the secular approximation, the exact analytic solution is obtained and the sufficient and necessary conditions for the indivisibility and the backflow of information for the system dynamics are presented. In the more general case, we investigate numerically the properties of the two measures for the case of Lorentzian reservoir. Our results show the importance of the counter-rotating terms to the short-time-scale non-Markovian behavior of the system dynamics, further expose the relation between the two measures and their rationality as non-Markovian measures. Finally, the complete positivity of the dynamics of the considered system is discussed.
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.
Boruett, Patrick; Kagai, Dorine; Njogo, Susan; Nguhiu, Peter; Awuor, Christine; Gitau, Lillian; Chalker, John; Ross-Degnan, Dennis; Wahlström, Rolf; Tomson, Göran
2013-07-01
Achieving high rates of adherence to antiretroviral therapy (ART) in resource-poor settings comprises serious, but different, challenges in both the first months of treatment and during the life-long maintenance phase. We measured the impact of a health system-oriented, facility-based intervention to improve clinic attendance and patient adherence. This was a quasi-experimental, longitudinal, controlled intervention study using interrupted time series analysis. The intervention consisted of (1) using a clinic appointment diary to track patient attendance and monitor monthly performance; (2) changing the mode of asking for self-reported adherence; (3) training staff on adherence concepts, intervention methods, and use of monitoring data; (4) conducting visits to support facility teams with the implementation.We conducted the study in 12 rural district hospitals (6 intervention, 6 control) in Kenya and randomly selected 1894 adult patients over 18 years of age in two cohorts: experienced patients on treatment for at least one year, and newly treated patients initiating ART during the study. Outcome measures were: attending the clinic on or before the date of a scheduled appointment, attending within 3 days of a scheduled appointment, reporting perfect adherence, and experiencing a gap in medication supply of more than 14 days. Among experienced patients, the percentage attending the clinic on or before a scheduled appointment increased in both level (average total increase immediately after intervention) (+5.7%; 95% CI=2.1, 9.3) and trend (increase per month) (+1.0% per month; 95% CI=0.6, 1.5) following the intervention, as did the level and trend of those keeping appointments within three days (+4.2%; 95% CI=1.6, 6.7; and +0.8% per month; 95% CI=0.6, 1.1, respectively). The relative difference between the intervention and control groups based on the monthly difference in visit rates increased significantly in both level (+6.5; 95% CI=1.4, 11.6) and trend (1.0% per
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.
Delahaye, Thibault; Nikitin, Andrei; Rey, Michaël; Szalay, Péter G; Tyuterev, Vladimir G
2014-09-14
In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82,542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm(-1) for fundamental bands centers and 5.9 cm(-1) for vibrational bands up to 7800 cm(-1). Large scale vibrational and rotational calculations for (12)C2H4, (13)C2H4, and (12)C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm(-1) are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of (13)C2H4 and (12)C2D4 and rovibrational levels of (12)C2H4.
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.
Lou, Jigang; Li, Huibo; Rong, Xin; Wu, Wenjie; Liu, Hao
2016-01-01
Previous studies reported that the location of the center of rotation (COR) at instrumented level after cervical total disc replacement (TDR) deviated from its preoperative location. However, currently, it is unknown whether the deviated COR is linked to the range of motion (ROM) at instrumented level. The purpose of this study was to evaluate the clinical outcomes after cervical TDR with ProDisc-C (Synthes, West Chester, PA, USA), as well as investigate the location change of COR at instrumented level and its clinical significance. A total of 23 patients who underwent single-level cervical TDR with ProDisc-C were included. Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) were used to assess clinical outcomes. Radiographic parameters such as cervical ROM, instrumented segmental ROM, adjacent segmental ROM, and intervertebral height were analyzed. Additionally, the location change of COR at instrumented level and its clinical significance were further analyzed by the alteration of its coordinates (COR-X, COR-Y). JOA scores increased significantly, while NDI scores decreased at final follow-up. No differences were found in cervical global ROM, instrumented segmental ROM, adjacent segmental ROM, and COR-Y at instrumented level between preoperative and final follow-up measurements (p>0.05); however, intervertebral height and COR-X increased significantly (p<0.05). Cervical global ROM, instrumented segmental ROM, and adjacent segmental ROM could be effectively maintained, and intervertebral height was increased after TDR with ProDisc-C. The location of COR at instrumented level shifted forward after cervical TDR.
NASA Astrophysics Data System (ADS)
Rao, K. Rama Koteswara; Suter, Dieter
2017-05-01
Quantum systems driven by strong oscillating fields are the source of many interesting physical phenomena. In this work, we experimentally study the dynamics of a two-level system of a single spin driven in the strong-driving regime where the rotating-wave approximation is not valid. This two-level system is a subsystem of a single nitrogen-vacancy (NV) center in diamond coupled to a first-shell 13C nuclear spin at a level anticrossing point. This near degeneracy occurs in the ms=±1 manifold of the electron spin when the energy level splitting between the ms=-1 and +1 states due to the static magnetic field is ≈127 MHz and thus equal to the splitting due to the 13C hyperfine interaction. The transition frequency of this electron spin two-level system in a static magnetic field of 28.9 G is 1.7 MHz and it can be driven only by the component of the radio-frequency (RF) field along the NV symmetry axis. Electron spin Rabi frequencies in this system can reach tens of MHz even for moderate RF powers. The simple sinusoidal Rabi oscillations that occur when the amplitude of the driving field is small compared to the transition frequency evolve into complex patterns when the driving field amplitude is comparable to or greater than the energy level splitting. We observe that the system oscillates faster than the amplitude of the driving field and the response of the system shows multiple frequencies.
The vibration-rotation-tunneling levels of N2-H2O and N2-D2O.
Wang, Xiao-Gang; Carrington, Tucker
2015-07-14
In this paper, we report vibration-rotation-tunneling levels of the van der Waals clusters N2-H2O and N2-D2O computed from an ab initio potential energy surface. The only dynamical approximation is that the monomers are rigid. We use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. The pattern of the cluster's levels is complicated by splittings caused by H-H exchange tunneling (larger splitting) and N-N exchange tunneling (smaller splitting). An interesting result that emerges from our calculation is that whereas in N2-H2O, the symmetric H-H tunnelling state is below the anti-symmetric H-H tunnelling state for both K = 0 and K = 1, the order is reversed in N2-D2O for K = 1. The only experimental splitting measurements are the D-D exchange tunneling splittings reported by Zhu et al. [J. Chem. Phys. 139, 214309 (2013)] for N2-D2O in the v2 = 1 region of D2O. Due to the inverted order of the split levels, they measure the sum of the K = 0 and K = 1 tunneling splittings, which is in excellent agreement with our calculated result. Other splittings we predict, in particular those of N2-H2O, may guide future experiments.
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.
McMurtry, C Meghan; Noel, Melanie; Taddio, Anna; Antony, Martin M; Asmundson, Gordon J G; Riddell, Rebecca Pillai; Chambers, Christine T; Shah, Vibhuti
2015-10-01
This systematic review evaluated the effectiveness of exposure-based psychological and physical interventions for the management of high levels of needle fear and/or phobia and fainting in children and adults. A systematic review identified relevant randomized and quasi-randomized controlled trials of children, adults, or both with high levels of needle fear, including phobia (if not available, then populations with other specific phobias were included). Critically important outcomes were self-reported fear specific to the feared situation and stimulus (psychological interventions) or fainting (applied muscle tension). Data were pooled using standardized mean difference (SMD) or relative risk with 95% confidence intervals. The systematic review included 11 trials. In vivo exposure-based therapy for children 7 years and above showed benefit on specific fear (n=234; SMD: -1.71 [95% CI: -2.72, -0.7]). In vivo exposure-based therapy with adults reduced fear of needles posttreatment (n=20; SMD: -1.09 [-2.04, -0.14]) but not at 1-year follow-up (n=20; SMD: -0.28 [-1.16, 0.6]). Compared with single session, a benefit was observed for multiple sessions of exposure-based therapy posttreatment (n=93; SMD: -0.66 [-1.08, -0.24]) but not after 1 year (n=83; SMD: -0.37 [-0.87, 0.13]). Non in vivo e.g., imaginal exposure-based therapy in children reduced specific fear posttreatment (n=41; SMD: -0.88 [-1.7, -0.05]) and at 3 months (n=24; SMD: -0.89 [-1.73, -0.04]). Non in vivo exposure-based therapy for adults showed benefit on specific fear (n=68; SMD: -0.62 [-1.11, -0.14]) but not procedural fear (n=17; SMD: 0.18 [-0.87, 1.23]). Applied tension showed benefit on fainting posttreatment (n=20; SMD: -1.16 [-2.12, -0.19]) and after 1 year (n=20; SMD: -0.97 [-1.91, -0.03]) compared with exposure alone. Exposure-based psychological interventions and applied muscle tension show evidence of benefit in the reduction of fear in pediatric and adult populations.
Hébert, Tiffany Michele; Maleki, Sara; Vasovic, Ljiljana V; Arnold, Jeffrey L; Steinberg, Jacob J; Prystowsky, Michael B
2014-03-01
Pathology residency training programs should aim to teach residents to think beyond the compartmentalized data of specific rotations and synthesize data in order to understand the whole clinical picture when interacting with clinicians. To test a collaborative autopsy procedure at Montefiore Medical Center (Bronx, New York), linking residents and attending physicians from anatomic and clinical pathology in the autopsy process from the initial chart review to the final report. Residents consult with clinical pathology colleagues regarding key clinical laboratory findings during the autopsy. This new procedure serves multiple functions: creating a team-based, mutually beneficial educational experience; actively teaching consultative skills; and facilitating more in-depth analysis of the clinical laboratory findings in autopsies. An initial trial of the team-based autopsy system was done from November 2010 to December 2012. Residents were then surveyed via questionnaire to evaluate the frequency and perceived usefulness of clinical pathology autopsy consultations. Senior residents were the most frequent users of clinical pathology autopsy consultation. The most frequently consulted services were microbiology and chemistry. Eighty-nine percent of the residents found the clinical pathology consultation to be useful in arriving at a final diagnosis and clinicopathologic correlation. The team-based autopsy is a novel approach to integration of anatomic and clinical pathology curricula at the rotation level. Residents using this approach develop a more holistic approach to pathology, better preparing them for meaningful consultative interaction with clinicians. This paradigm shift in training positions us to better serve in our increasing role as arbiters of outcomes measures in accountable care organizations.
Niu, Shu-Fen; Chu, Hsin; Chen, Chiung-Hua; Chung, Min-Huey; Chang, Yu-Shiun; Liao, Yuan-Mei; Chou, Kuei-Ru
2013-10-01
Sleep deficit affects neurobehavioral functioning, reduces attention and cognitive function, and negatively impacts occupational safety. This study investigated selective attention levels of nursing staff on different shifts. Using a prospective, randomized parallel group study, selective attention was measured using the d2 test in 62 nursing staff in a medical center in Taiwan. There were significant differences in selective attention indicators (E%) between the fixed-day-shift group (control group) and rotating-shift group (experimental group): The percentage of errors (E%) for night-shift workers in the rotating-shift group was higher than that of fixed-day-shift workers, while the total number of items scanned minus error (TN - E) and concentration performance (CP) scores were higher for fixed-day-shift workers. Within the experimental group, the error rate on night shift was 0.44 times more than that on day shift and .62 times more than on evening shift; the TN-E on night shift was 38.99 items less than that on day shift, and the CP was 27.68 items less on night shift than on day shift; indicating that staff on the night shift demonstrated poorer speed and accuracy on the overall test than did the staff on day shifts. Inadequate sleep and a state of somnolence adversely affected the attention and operation speed of work among night-shift workers. More than 2 days off is suggested when shifting from the night shift to other shifts to provide adequate time for circadian rhythms to adjust.
Van Kleunen, Jonathan P; Tucker, Scott A; Field, Larry D; Savoie, Felix H
2012-11-01
%) tear of the infraspinatus in combination with glenohumeral internal rotation deficit (GIRD) and SLAP tears in the throwing athlete results in a guarded prognosis in return to play at the same level. While the rates of return to play in overhead-throwing athletes with an isolated SLAP tear have historically been encouraging, the prognosis for an athlete with both a SLAP and infraspinatus tear is more guarded. These patients are not likely to return to their preinjury level of play.
Leforestier, Claude; van Harrevelt, Rob; van der Avoird, Ad
2009-11-05
The 12-dimensional ab initio potential for the water dimer with flexible monomers from Huang et al. (J. Chem. Phys. 2008, 128, 034312) was used in accurate calculations of the vibration-rotation-tunneling (VRT) levels of (H2O)2 and (D2O)2 involving the intermolecular rovibrational and tunneling states as well as the intramolecular vibrations. For the intermolecular VRT levels we used a 6 + 6d model in which the fast intramolecular vibrations are adiabatically separated from the much slower intermolecular vibrations, tunneling motions, and overall rotations. We also tested two six-dimensional (6d) rigid monomer models in which the monomers were frozen either at their equilibrium geometry or at their ground state vibrationally averaged geometry. All the results from the 6 + 6d model agree well with the large amount of detailed experimental data available from high-resolution spectroscopy. For most of the parameters characterizing the spectra the results of the two 6d rigid monomer models do not significantly differ from the 6 + 6d results. An exception is the relatively large acceptor tunneling splitting, which was the only quantity for which the 6d model with the monomers frozen at their equilibrium geometry was not in good agreement with the experimental data. The 6d model with monomers at their vibrationally averaged geometry performs considerably better, and the full 6 + 6d results agree with the measurements also for this quantity. For the excited intramolecular vibrations we tested two 6 + 6d models. In the first model the excitation was assumed to be either on the donor in the hydrogen bond or on the acceptor, and to hop from one monomer to the other upon donor-acceptor interchange. In the second model the monomer excitation remains localized on a given monomer for all dimer geometries. Almost the same frequencies of the intramolecular vibrations were found for the two models. The calculations show considerable variations in the frequencies of the
NASA Astrophysics Data System (ADS)
Dawadi, Mahesh B.; Michael Lindsay, C.; Chirokolava, Andrei; Perry, David S.; Xu, Li-Hong
2013-03-01
The high-resolution infrared spectrum of methylamine (CH3NH2) has been recorded using slit-jet direct absorption spectroscopy in the ν11 CH-stretch region (2965-3005 cm-1) with a resolution of 0.0025 cm-1. The 621 lines assigned by ground state combination differences represent 27 substates with |K'| ≤ 2 for the A, B, E1, and E2 symmetries. The spectrum of CH3NH2 is complicated by torsion and inversion tunneling connecting six equivalent minima. The upper states K' = 0, ± 1 for E1 and E2 are substantially perturbed by "dark" states. The result in the spectrum is multiplets of 2 or 3 states with mixed bright/dark character. The analysis of the spectrum reveals two qualitative differences in the energy level pattern relative to the vibrational ground state and relative to available data on the lower frequency vibrations (NH2 wag and CN stretch). First at J' = 0, there is a different ordering of the levels connected by torsion-inversion tunneling. Second, the low-J splittings indicative of torsion-rotation coupling are greatly reduced in the ν11 excited state relative to the vibrational ground state for both the E1 and E2 species, suggesting the partial suppression of torsional tunneling in the ν11 CH-stretch excited state.
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.
Delahaye, Thibault Rey, Michaël Tyuterev, Vladimir G.; Nikitin, Andrei; Szalay, Péter G.
2014-09-14
In this paper we report a new ground state potential energy surface for ethylene (ethene) C{sub 2}H{sub 4} obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C{sub 2}H{sub 4} molecule was obtained with a RMS(Obs.–Calc.) deviation of 2.7 cm{sup −1} for fundamental bands centers and 5.9 cm{sup −1} for vibrational bands up to 7800 cm{sup −1}. Large scale vibrational and rotational calculations for {sup 12}C{sub 2}H{sub 4}, {sup 13}C{sub 2}H{sub 4}, and {sup 12}C{sub 2}D{sub 4} isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm{sup −1} are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of {sup 13}C{sub 2}H{sub 4} and {sup 12}C{sub 2}D{sub 4} and rovibrational levels of {sup 12}C{sub 2}H{sub 4}.
Quasi-moire patterns: their generation and geometry
NASA Astrophysics Data System (ADS)
Meilan, Pablo F.; Zalvidea, Dobryna; Garavaglia, Mario
2001-08-01
This paper deals with the observation of quasi-moire patterns generated when an original 2D transparency is superimposed onto a copy of itself, and coplanarly rotated. Patterns are also observed if one of the transparency is the scaled-up or -down replica of the original. Also, patterns are observed if different scaling coefficients are applied in different directions. Besides, the quasi-moire patterns are observed when one of the transparencies is skewed. Quasi-moire patterns are generated by autocorrelation between the pair of transparencies: circular, elliptical, parabolic, hyperbolical, radial lines, and logarithmic spirals quasi-moire patterns are generated and that can be associated with generalized conics curves.
2013-01-01
Background Achieving high rates of adherence to antiretroviral therapy (ART) in resource-poor settings comprises serious, but different, challenges in both the first months of treatment and during the life-long maintenance phase. We measured the impact of a health system-oriented, facility-based intervention to improve clinic attendance and patient adherence. Methods This was a quasi-experimental, longitudinal, controlled intervention study using interrupted time series analysis. The intervention consisted of (1) using a clinic appointment diary to track patient attendance and monitor monthly performance; (2) changing the mode of asking for self-reported adherence; (3) training staff on adherence concepts, intervention methods, and use of monitoring data; (4) conducting visits to support facility teams with the implementation. We conducted the study in 12 rural district hospitals (6 intervention, 6 control) in Kenya and randomly selected 1894 adult patients over 18 years of age in two cohorts: experienced patients on treatment for at least one year, and newly treated patients initiating ART during the study. Outcome measures were: attending the clinic on or before the date of a scheduled appointment, attending within 3 days of a scheduled appointment, reporting perfect adherence, and experiencing a gap in medication supply of more than 14 days. Results Among experienced patients, the percentage attending the clinic on or before a scheduled appointment increased in both level (average total increase immediately after intervention) (+5.7%; 95% CI = 2.1, 9.3) and trend (increase per month) (+1.0% per month; 95% CI = 0.6, 1.5) following the intervention, as did the level and trend of those keeping appointments within three days (+4.2%; 95% CI = 1.6, 6.7; and +0.8% per month; 95% CI = 0.6, 1.1, respectively). The relative difference between the intervention and control groups based on the monthly difference in visit rates increased significantly in both
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.
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
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.
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.
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.
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.
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.
Generalized quasi variational inequalities
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.
Toward a Principled Sampling Theory for Quasi-Orders.
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.
Toward a Principled Sampling Theory for Quasi-Orders
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
Quasi-Lower Dimension and Quasi-Lipschitz Mapping
NASA Astrophysics Data System (ADS)
Chen, Haipeng; Du, Yali; Wei, Chun
In this paper, we show that the lower dimension is not invariant under quasi-Lipschitz mapping, and then we find an invariant named the quasi-lower dimension. We also compute the quasi-lower dimension of a class of sets defined by digit restrictions, and then give an example to distinguish the quasi-lower dimension and other dimensions.
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.
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
NASA Astrophysics Data System (ADS)
Pohlman, Nicholas A.; Paprocki, Daniel F., Jr.; Si, Yun
2012-11-01
Typically in rotating tumblers, constant rotation rates and circular cross-sections are used as they jointly produce a steady, uniform flowing layer at the free surface. On the other hand, experiments conducted in polygon-shaped tumblers produce unsteady conditions due to the rapidly changing flowing layer length. Results analyzing free surface properties indicate that the particle dynamics within the flowing layer attempt to minimize energy of the flowing system: The arithmetic difference between the angle of repose and the tumbler orientation has a functional relationship with the instantaneous flowing layer length in the form of a catenary. The peaks of the catenary are affected by the number of sides on the polygon cross-section as well as the symmetry around the critical 50% fill fraction. Furthermore, oscillation of the flowing layer position appears to affect the free surface curvature. This result is likely due to the rapidly increasing and decreasing length of the free surface and the rotational inertia of particles entering the flowing layer. Funding provided by NIU's Office of Student Engagement and Experiential Learning.
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.
Anderst, William J; West, Tyler; Donaldson, William F; Lee, Joon Y; Kang, James D
2016-11-15
A longitudinal study using biplane radiography to measure in vivo intervertebral range of motion (ROM) during dynamic flexion/extension, and rotation. To longitudinally compare intervertebral maximal ROM and midrange motion in asymptomatic control subjects and single-level arthrodesis patients. In vitro studies consistently report that adjacent segment maximal ROM increases superior and inferior to cervical arthrodesis. Previous in vivo results have been conflicting, indicating that maximal ROM may or may not increase superior and/or inferior to the arthrodesis. There are no previous reports of midrange motion in arthrodesis patients and similar-aged controls. Eight single-level (C5/C6) anterior arthrodesis patients (tested 7 ± 1 months and 28 ± 6 months postsurgery) and six asymptomatic control subjects (tested twice, 58 ± 6 months apart) performed dynamic full ROM flexion/extension and axial rotation whereas biplane radiographs were collected at 30 images per second. A previously validated tracking process determined three-dimensional vertebral position from each pair of radiographs with submillimeter accuracy. The intervertebral maximal ROM and midrange motion in flexion/extension, rotation, lateral bending, and anterior-posterior translation were compared between test dates and between groups. Adjacent segment maximal ROM did not increase over time during flexion/extension, or rotation movements. Adjacent segment maximal rotational ROM was not significantly greater in arthrodesis patients than in corresponding motion segments of similar-aged controls. C4/C5 adjacent segment rotation during the midrange of head motion and maximal anterior-posterior translation were significantly greater in arthrodesis patients than in the corresponding motion segment in controls on the second test date. C5/C6 arthrodesis appears to significantly affect midrange, but not end-range, adjacent segment motions. The effects of arthrodesis on adjacent segment motion
Photonic quasi-crystal terahertz lasers
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
Photonic quasi-crystal terahertz lasers.
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.
Crawford, R J; Kearns, M P
2003-10-01
Rotational moulding promises designers attractive economics and a low-pressure process. The benefits of rotational moulding are compared here with other manufacturing methods such as injection and blow moulding.
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.âº Asteroid and...
Cui, Zhumei; Chen, Yeming; Kong, Xiangzhen; Zhang, Caimeng; Hua, Yufei
2014-02-19
The adsorption of heat-denatured soy proteins at the oil/water (O/W) interface during emulsification was studied. Protein samples were prepared by heating protein solutions at concentrations of 1-5% (w/v) and were then diluted to 0.3% (w/v). The results showed that soy proteins that had been heated at higher concentrations generated smaller droplet size of emulsion. Increase in homogenizer rotating speed resulted in higher protein adsorption percentages and lower surface loads at the O/W interface. Surface loads for both unheated and heated soy proteins were linearly correlated with the unadsorbed proteins' equilibrium concentration at various rotating speeds. With the rise in NaCl addition level, protein adsorption percentage and surface loads of emulsions increased, whereas lower droplet sizes were obtained at the ionic strength of 0.1 M. The aggregates and non-aggregates displayed different adsorption behaviors when rotating speed or NaCl concentration was varied.
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.
Signorile, Joseph F; Lew, Karen; Stoutenberg, Mark; Pluchino, Alessandra; Lewis, John E; Gao, Jinrun
2014-06-30
The leg extension (LE) is commonly used to strengthen the quadriceps muscles during training and rehabilitation. This study examined the effects of limb position (POS) and range of motion (ROM) on quadriceps electromyography (EMG) during 8 repetitions (REP) of LE. Twenty-four participants performed eight LE REP at their 8-repetition maximum with lower limbs medially rotated (TI), laterally rotated (TO), and neutral (NEU). Each REP EMG was averaged over the first, middle, and final 0.524 rad ROM. For vastus medialis oblique (VMO), a REP x ROM interaction was detected (p<0.02). The middle 0.524 rad produced significantly higher EMG than the initial 0.524 rad for REP 6-8 and the final 0.524 rad produced higher EMG than the initial 0.524 rad for REP 1, 2, 3, 4, 6, 8 (p<0.05). For rectus femoris (RF), EMG activity increased across REP with TO generating the greatest activity (p<0.001). For vastus lateralis (VL), EMG increased across REP (p<0.001) with NEU and TO EMG increasing linearly throughout ROM, and TI activity greatest during the middle 0.524 rad. We conclude that to target the VMO the optimal ROM is the final 1.047 rad regardless of POS, while maximum EMG for the RF is generated using TO regardless of ROM. In contrast, the VL is maximally activated using TI over the first 1.047 rad ROM or in NEU over the final 0.524 rad ROM.
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
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.
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
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…
Chang, Yu-San; Chen, Hsiang-Lan; Wu, Yu-Hsuan; Hsu, Chung-Yao; Liu, Ching-Kuan; Hsu, Chin
2014-08-05
We investigated circadian changes and effects on mood, sleep-related hormones and cognitive performance when nurses worked consecutive night shifts in a rapidly rotating shift system. Daytime cognitive function, sleep propensity and sleep-related hormones (growth hormone, cortisol, prolactin, thyrotropin) were compared after participants worked two and four consecutive night shifts. Twenty-three off-duty nurses, 20 nurses working two consecutive night shifts and 16 nurses working four consecutive night shifts were enrolled. All participants completed the Maintenance of Wakefulness Test, State-Trait Anxiety Inventory, Stanford Sleepiness Scale, visual attention tasks (VAT), Wisconsin Card Sorting Test, and modified Multiple Sleep Latency Test. Hormone levels were also measured four times throughout the day, at 2-h intervals. During the day, the participants in the night shift groups were less able to maintain wakefulness, had poor performance on VAT, and higher thyrotropin levels than did those in the off-duty group. Participants who worked two night shifts were better able to maintain wakefulness, had higher anxiety scale scores, poorer initial performance and lack of learning effect on VAT, and higher prolactin levels compared with those who worked four night shifts. There were no differences in cortisol levels between the two- and four- shift groups. Rotating night shifts too quickly may cause anxiety and decreased attentional performance, and may impact daytime prolactin levels after night shifts. It is possible that the two-shift group had a higher cortisol level than did the four-shift group, which would be consistent with the group's higher state anxiety scores. The negative findings may be due to the small sample size. Further studies on the effects of consecutive night shifts on mood and cortisol levels during the daytime after sleep restriction would be valuable.
Quasi-Normal Modes of Stars and Black Holes.
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.
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.
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.
Bubble trajectories in rotating drops
NASA Technical Reports Server (NTRS)
Brone, D.; Cole, R.
1991-01-01
The investigation summarized in this paper describes recent normal gravity experiments involving the behavior of compound drops in rotating flows and in particular, the subsequent migration of the less dense phase (air bubble) toward the rotation axis. The data are compared to two models. The first was developed to predict the trajectory of a fluid particle in an infinitely large drop in the presence of both gravitational and rotational fields at the limit of quasi-steady creeping flow. The second predicts the trajectory of a fluid particle in a compound drop in the presence of a rotational field and at the limit of creeping flow. Gravity has not yet been incorporated into this second model.
Qiu, Wu; Yuan, Jing; Ukwatta, Eranga; Tessier, David; Fenster, Aaron
2013-07-01
Prostate segmentation is an important step in the planning and treatment of 3D end-firing transrectal ultrasound (TRUS) guided prostate biopsy. In order to improve the accuracy and efficiency of prostate segmentation in 3D TRUS images, an improved level set method is incorporated into a rotational-slice-based 3D prostate segmentation to decrease the accumulated segmentation errors produced by the slice-by-slice segmentation method. A 3D image is first resliced into 2D slices in a rotational manner in both the clockwise and counterclockwise directions. All slices intersect approximately along the rotational scanning axis and have an equal angular spacing. Six to eight boundary points are selected to initialize a level set function to extract the prostate contour within the first slice. The segmented contour is then propagated to the adjacent slice and is used as the initial contour for segmentation. This process is repeated until all slices are segmented. A modified distance regularization level set method is used to segment the prostate in all resliced 2D slices. In addition, shape-constraint and local-region-based energies are imposed to discourage the evolved level set function to leak in regions with weak edges or without edges. An anchor point based energy is used to promote the level set function to pass through the initial selected boundary points. The algorithm's performance was evaluated using distance- and volume-based metrics (sensitivity (Se), Dice similarity coefficient (DSC), mean absolute surface distance (MAD), maximum absolute surface distance (MAXD), and volume difference) by comparison with expert delineations. The validation results using thirty 3D patient images showed that the authors' method can obtain a DSC of 93.1% ± 1.6%, a sensitivity of 93.0% ± 2.0%, a MAD of 1.18 ± 0.36 mm, a MAXD of 3.44 ± 0.8 mm, and a volume difference of 2.6 ± 1.9 cm(3) for the entire prostate. A reproducibility experiment demonstrated that the proposed method
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.
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
Felluga, Margherita; Rabach, Ingrid; Minute, Marta; Montico, Marcella; Giorgi, Rita; Lonciari, Isabella; Taddio, Andrea; Barbi, Egidio
2016-05-01
The aim of the study is to investigate if the presence of medical clowns during painful procedures in the emergency department (ED) affects children's anxiety and pain. Forty children (4-11 years) admitted to the ED with the need of painful procedures were prospectively enrolled. They were randomly assigned to the clown group, where children interacted with clowns or to the control group in which they were entertained by parents and ED nurses. The children's anxiety was assessed by the Children's Anxiety and Pain Scales; pain was evaluated with the Numerical Rating Scale and Wong-Backer Scale, according to the children's age. Staff and clown's opinions were evaluated by means of dedicated questionnaires. Children's anxiety levels in the clown group were significantly lower than those compared with the control group, while children's pain levels did not change between the two groups. The presence of clowns in the ED before and during painful procedures was effective in reducing children's anxiety. • Anxiety and fear caused by medical procedures exacerbate children's pain and may interfere with the procedure. • To reduce anxiety, fear, and pain and to facilitate patient's evaluation, different non-pharmacological approaches have been proposed and positive effects of laughter and humor have been reported. What is New: • The presence of clowns in the waiting room and in the ED during medical evaluation and painful procedures helps to reduce children's anxiety.
Simulation of Non-resonant Internal Kink Mode with Toroidal Rotation in NSTX
Fu, Guoyong
2013-07-16
Plasmas in spherical and conventional tokamaks, with weakly reversed shear q pro le 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 (NTMs)1 . The mode can also lead to large energetic particle transport and signi cant broadening of beam-driven current. Motivated by these important e ects, we have carried out extensive nonlinear simulations of the mode with nite toroidal rotation using parameters and pro les of an NTSX plasma with a weakly reversed shear pro le. The numerical results show that, at the experimental level, plasma rotation has little e ect on either equilibrium or linear stability. However, rotation can signi cantly inuence the nonlinear dynamics of the (1, 1) mode and the the induced (2, 1) magnetic island. The simulation results show that a rotating helical equilibrium is formed and maintained in the nonlinear phase at nite 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 e ects of rotation are found to greatly suppress the (2, 1) magnetic island even at a low level.
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…
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…
NASA Technical Reports Server (NTRS)
Koker, Edmond B.
1995-01-01
The importance of the OH radical as an intermediate in many combustion reactions and in atmospheric photochemistry has led many researchers to use it as a diagnostic tool in these processes. The amount of data that has been acquired over the years for this radical is quite considerable. However, the quenching rate of OH with water molecules as a function of temperature and the rotational level of the excited state is not very well understood. The motivation of the studies undertaken is to bridge the gap between the low temperature measurements and the high temperature ones reported in the literature. The technique generally employed in these diagnostics is laser-induced fluorescence (LIF), through which rotational state selective excitation of the radical is possible. Furthermore, in a combustion medium, water is produced in abundance so that knowledge of the quenching rate of OH due to water molecules plays a crucial role in interpreting the data. In general, the precursor to an understanding of the collisional quenching rates of OH involves a characterization of the mode in which the radical is produced; the resulting rotational and translational distribution, followed by a measurement of the OH temperature; and ultimately obtaining the rate constants from the pressure dependence of the fluorescence signal. The experimental implementation of these measurements therefore involved, as a first step, the production of the OH radicals in a microwave discharge cell using water vapor as the source, wherein a hydrogen atom is abstracted from H2O. The second step involved the absorption of photons from the frequency-doubled output of a pulsed amplified, single-frequency cw ring dye laser. By tuning the laser to the peak of the transition and observing the fluorescence decay after the laser pulse, the lifetime of the OH in a particular rotational electronic state was determined (tau = 1.4 microseconds for Q(sub 1)(3)). Knowledge of this parameter led to a determination of
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
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.
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.
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…
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…
NASA Astrophysics Data System (ADS)
Fries, Christian; Weitz, Marco; Theobald, Christian; v. Löwis of Menar, Patric; Bartschke, Jürgen; L'huillier, Johannes A.
2015-02-01
With the advent of high power and narrow bandwidth 969 nm pump diodes, direct pumping into the upper laser level of Yb:YAG and hence quasi-2-level lasers became possible. Pumping directly into the emitting level leads to higher quantum efficiency and reduction of non-radiative decay. Consequently, thermal load, thermal lensing and risk of fracture are reduced significantly. Moreover pump saturation and thermal population of uninvolved energy-levels in ground and excited states are benefical for a homogenous distribution of the pump beam as well as the reduction of reabsorption loss compared to 3-level systems, which allows for high-power DPSS lasers. Beside continuous-wave (cw) operation, nanosecond pulses with a repetition rate between 1 and 5 kHz are an attractive alternative to flashlamp-pumped systems (10-100 Hz) in various measurement applications that require higher data acquisition rates because of new faster detectors. Based on measurements of the absorption and a detailed numerical model for pump beam distribution, including beam propagation and saturation factors, power-scaling of a ceramic rod Yb:YAG oscillator was possible. Finally a cw output power of 50 W with 33 % pump efficiency at 1030 nm has been demonstrated (M2 < 1.2). Nanosecond pulses have been produced by cavity-dumping of this system. The cavity-dumped setup allowed for 3-10 ns pulses with a pulse energy of 12.5 mJ at 1 kHz (M2 < 1.1). In order to achieve these results a systematic experimental and numerical investigation on gain dynamics and the identification of different stable operating regimes has been carried out.
NASA Astrophysics Data System (ADS)
Vassiliev, Dmitri
2017-04-01
We consider an infinite three-dimensional elastic continuum whose material points experience no displacements, only rotations. This framework is a special case of the Cosserat theory of elasticity. Rotations of material points are described mathematically by attaching to each geometric point an orthonormal basis that gives a field of orthonormal bases called the coframe. As the dynamical variables (unknowns) of our theory, we choose the coframe and a density. We write down the general dynamic variational functional for our rotational theory of elasticity, assuming our material to be physically linear but the kinematic model geometrically nonlinear. Allowing geometric nonlinearity is natural when dealing with rotations because rotations in dimension three are inherently nonlinear (rotations about different axes do not commute) and because there is no reason to exclude from our study large rotations such as full turns. The main result of the talk is an explicit construction of a class of time-dependent solutions that we call plane wave solutions; these are travelling waves of rotations. The existence of such explicit closed-form solutions is a non-trivial fact given that our system of Euler-Lagrange equations is highly nonlinear. We also consider a special case of our rotational theory of elasticity which in the stationary setting (harmonic time dependence and arbitrary dependence on spatial coordinates) turns out to be equivalent to a pair of massless Dirac equations. The talk is based on the paper [1]. [1] C.G.Boehmer, R.J.Downes and D.Vassiliev, Rotational elasticity, Quarterly Journal of Mechanics and Applied Mathematics, 2011, vol. 64, p. 415-439. The paper is a heavily revised version of preprint https://arxiv.org/abs/1008.3833
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
Qiu, Wu; Yuan, Jing; Ukwatta, Eranga; Tessier, David; Fenster, Aaron
2012-01-01
Prostate segmentation in 3D ultrasound images is an important step in the planning and treatment of 3D end-firing transrectal ultrasound (TRUS) guided prostate biopsy. A semi-automatic prostate segmentation method is presented in this paper, which integrates a modified distance regularization level set formulation with shape constraint to a rotational-slice-based 3D prostate segmentation method. Its performance, using different metrics, has been evaluated on a set of twenty 3D patient prostate images by comparison with expert delineations. The volume overlap ratio of 93.39 +/- 1.26% and the mean absolute surface distance of 1.16 +/- 0.34 mm were found in the quantitative validation result.
Huang, X; Braams, Bastiaan J; Bowman, Joel M; Kelly, Ross E A; Tennyson, Jonathan; Groenenboom, Gerrit C; van der Avoird, Ad
2008-01-21
We report a new full-dimensional potential energy surface (PES) for the water dimer, based on fitting energies at roughly 30,000 configurations obtained with the coupled-cluster single and double, and perturbative treatment of triple excitations method using an augmented, correlation consistent, polarized triple zeta basis set. A global dipole moment surface based on Moller-Plesset perturbation theory results at these configurations is also reported. The PES is used in rigorous quantum calculations of intermolecular vibrational frequencies, tunneling splittings, and rotational constants for (H2O)2 and (D2O)2, using the rigid monomer approximation. Agreement with experiment is excellent and is at the highest level reported to date. The validity of this approximation is examined by comparing tunneling barriers within that model with those from fully relaxed calculations.
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.
Quasi-Local Masses of Rotating Space-Times*
NASA Astrophysics Data System (ADS)
Zeng, Xiao-Xiong; Li, Ling
2017-09-01
We derive the Misner-Sharp-like masses of the Reissner–Nordström black hole and the Einstein–Maxwell–Dilaton–Axion black hole by using the modified first law of thermodynamics. Their surface tensions are investigated. For the Reissner–Nordström black hole, the outer horizon radius is treated as a variable and the effective temperature is introduced. For the Einstein–Maxwell–Dilaton–Axion black hole, the outer horizon radius, the angular momentum unit mass and the parameter b are seen as three independent variables, and the mass, the horizon area and the angular momentum are functions of them.
Quasi-one-dimensional density of states in a single quantum ring
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
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.
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.
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.
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)
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)
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.
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.
Sociology as a Discipline: Quasi-Science and Quasi- Humanities.
ERIC Educational Resources Information Center
Zald, Mayer N.
1991-01-01
Traces the occupational and intellectual components of sociology's effort to win recognition as a science. Focuses on the model of science used and its limits. Argues that sociology, as quasi-science and quasi-humanities, should be maintaining the empirical outlook of a science while recognizing the impact of civilization on concepts and theories.…
NASA Astrophysics Data System (ADS)
Hum, David S.; Fejer, Martin M.
2007-03-01
The use of microstructured crystals in quasi-phasematched (QPM) nonlinear interactions has enabled operation of nonlinear devices in regimes inaccessible to conventional birefringently phasematched media. This review addresses basic aspects of the theory of QPM interactions, microstructured ferroelectrics and semiconductors for QPM, devices based on QPM media, and a series of techniques based on engineering of QPM gratings to tailor spatial and spectral response of QPM interactions. Because it is not possible in a brief review to do justice to the large body of results that have been obtained with QPM media over the past twenty years, the emphasis in this review will be on aspects of QPM interactions beyond their use simply as highly nonlinear alternatives to conventional birefringent media. To cite this article: D.S. Hum, M.M. Fejer, C. R. Physique 8 (2007).
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.
Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.
2016-04-14
Here, the C ^{1}B_{2} state of SO_{2} 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 (b_{2} 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 b_{2} 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 a_{1} and b_{2} vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.
Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.
2016-04-14
Here, the C ^{1}B_{2} state of SO_{2} 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 (b_{2} 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 b_{2} 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 a_{1} and b_{2} vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.
Rotational Orientation Effects in NO(X) + Ar Inelastic Collisions.
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.
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.
Hyperion: Rotational dynamics.
NASA Astrophysics Data System (ADS)
Black, G. J.; Nicholson, P. D.; Thomas, P. C.
1995-09-01
We have numerically integrated the full three dimensional rotation of Hyperion using as initial conditions the moments of inertia, pole position, and spin rate from a solution based on fitting control points, limb, and terminator positions in high-resolution Voyager 2 images (P. C. Thomas et al. 1995, Icarus ). These images were taken over a 38-hr period and cover ˜114° of rotation. From this solution, it is found that at the time of the Voyager 2 encounter (23 August 1981) the instantaneous spin axis was tilted ˜60° from the orbit normal and was roughly aligned with the axis of minimum moment of inertia. In addition, the instantaneous spin rate is found to have been 72° +3-4 per day, or about 4.2 times the synchronous rate. The integrated dynamical model using this solution provides an excellent fit to the lightcurve obtained from earlier low resolution Voyager 2 images, whereas a fit assuming a constant rotation pole and spin rate clearly does not. The largest amplitude component in the lightcurve is due to the free precession (wobble) rather than to the rotation itself. Previous work by J. Wisdom, S. J. Peale, and F. Mignard (1984, Icarus 58, 137-152) showed that it was likely that Hyperion would be in a chaotically tumbling state, and groundbased observations by J. J. Klavetter (1989, Astron. J. 97, 570-579; 98, 1855-1874) in 1987 could not be explained by any simply periodic rotation and are consistent with a chaotic state. Although Hyperion's rotation state is indeed formally chaotic, with the shortest Lyapunov time on the order of the orbital period or less (J. Wisdom et al. 1984, Astron. J. 94, 1350-1360), the short-term motion of the spin axis in 1981 appears "quasi-regular," undergoing forced precession with a period of ˜300 days and wobbling with a period of ˜7 days. Our integrations show that the unusual spin state seen by Voyager 2 can persist for several thousand years, although the chaotic nature of the motion limits the predictability of our
New Classes of Quasi-helically Symmetric Stellarators
L.P. Ku and A.H. Boozer
2010-08-09
New classes of quasi-helically symmetric stellarators with aspect ratios ≤ 10 have been found which are stable to the perturbation of magnetohydrodynamic modes at plasma pressures of practical interest. These configurations have large rotational transform and good quality of flux surfaces. Characteristics of some selected examples are discussed in detail. The feasibility of using modular coils for these stellarators has been investigated. It is shown that practical designs for modular coils can be achieved.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Yano, J.-I.; Plant, R. S.
2012-12-01
The concept of convective quasi-equilibrium (CQE) is a key ingredient in order to understand the role of deep moist convection in the atmosphere. It has been used as a guiding principle to develop almost all convective parameterizations and provides a basic theoretical framework for large-scale tropical dynamics. The CQE concept as originally proposed by Arakawa and Schubert (1974) is systematically reviewed from wider perspectives. Various interpretations and extensions of Arakawa and Schubert's CQE are considered both in terms of a thermodynamic analogy and as a dynamical balance. The thermodynamic interpretations can be more emphatically embraced as a homeostasis. The dynamic balance interpretations can be best understood by analogy with the slow manifold. Various criticisms of CQE can be avoided by taking the dynamic balance interpretation. Possible limits of CQE are also discussed, including the importance of triggering in many convective situations, as well as the possible self-organized criticality of tropical convection. However, the most intriguing aspect of the CQE concept is that in spite of many observational tests supporting and interpreting it in many different senses, it has never been established in a robust manner based on a systematic analysis of the cloud work function budget by observations as was originally defined.
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.
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.
Dynamos in rotating compressible convection
NASA Astrophysics Data System (ADS)
Favier, B.; Bushby, P. J.
2011-12-01
Motivated by open questions in fundamental dynamo theory, the overall aim of this paper is to investigate some of the properties of dynamo action in rotating compressible convection. We study dynamo action in a convective layer of electrically-conducting, compressible fluid, rotating about the vertical axis. In order to identify the effects of rotation, we also carry out an equivalent set of calculations of convectively-driven dynamo action in a non-rotating layer. Whether or not the layer is rotating, the convection acts as a small-scale dynamo provided that the magnetic diffusivity is small enough. Defining the magnetic Reynolds number in terms of the horizontal scales of motion, we find that rotation reduces the critical value of this parameter above which dynamo action is observed. In the nonlinear regime, a rotating dynamo calculation and a separate non-rotating simulation are found to saturate at a similar level, even though the mid-layer value of the local magnetic Reynolds number is smaller in the rotating case. We compute the Lyapunov exponents of the flow to show that the stretching properties of the convection are modified by rotation. Furthermore, rotation significantly reduces the magnetic energy dissipation in the lower part of the layer.
Properties of relativistically rotating quark stars
NASA Astrophysics Data System (ADS)
Zhou, Enping
2017-06-01
In this work, quasi-equilibrium models of rapidly rotating triaxially deformed quark stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polynomial equation of state. Especially, since we are using a full 3-D numerical relativity initial data code, we are able to consider the triaxially deformed rotating quark stars at very high spins. Such triaxially deformed stars are possible gravitational radiation sources detectable by ground based gravitational wave observatories. Additionally, the bifurcation from axisymmetric rotating sequence to triaxially rotating sequence hints a more realistic spin up limit for rotating compact stars compared with the mass-shedding limit. With future observations such as sub-millisecond pulsars, we could possibly distinguish between equation of states of compact stars, thus better understanding strong interaction in the low energy regime.
Potential Vorticity Diagnosis of a Simulated Hurricane. Part I: Formulation and Quasi-Balanced Flow.
NASA Astrophysics Data System (ADS)
Wang, Xingbao; Zhang, Da-Lin
2003-07-01
Because of the lack of three-dimensional (3D) high-resolution data and the existence of highly nonelliptic flows, few studies have been conducted to investigate the inner-core quasi-balanced characteristics of hurricanes. In this study, a potential vorticity (PV) inversion system is developed, which includes the nonconservative processes of friction, diabatic heating, and water loading. It requires hurricane flows to be statically and inertially stable but allows for the presence of small negative PV. To facilitate the PV inversion with the nonlinear balance (NLB) equation, hurricane flows are decomposed into an axisymmetric, gradient-balanced reference state and asymmetric perturbations. Meanwhile, the nonellipticity of the NLB equation is circumvented by multiplying a small parameter and combining it with the PV equation, which effectively reduces the influence of anticyclonic vorticity. A quasi-balanced equation in pseudoheight coordinates is derived, which includes the effects of friction and diabatic heating as well as differential vorticity advection and the Laplacians of thermal advection by both nondivergent and divergent winds.This quasi-balanced PV- inversion system is tested with an explicit simulation of Hurricane Andrew (1992) with the finest grid size of 6 km. It is shown that (a) the PV- inversion system could recover almost all typical features in a hurricane, and (b) a sizeable portion of the 3D hurricane flows are quasi-balanced, such as the intense rotational winds, organized eyewall updrafts and subsidence in the eye, cyclonic inflow in the boundary layer, and upper-level anticyclonic outflow. It is found, however, that the boundary layer cyclonic inflow and upper-level anticyclonic outflow also contain significant unbalanced components. In particular, a low-level outflow jet near the top of the boundary layer is found to be highly unbalanced (and supergradient). These findings are supported by both locally calculated momentum budgets and
A shallow quasi-balanced model on the sphere
NASA Astrophysics Data System (ADS)
Silvers, L. G.
2010-12-01
Nonlinear dynamics of a shallow fluid layer over the full domain of a rotating sphere are examined. A simple quasi-balanced model has been developed that allows for a unified investigation of the midlatitude, equatorial, and polar balanced motions. These motions are based strictly on the evolution of potential vorticity. Quasi-geostrophic theory has been an extremely useful tool for studying the dynamics of large-scale atmospheric and oceanic phenomena but is limited by its restriction to the midlatitudes. The simplicity of quasi-geostrophic theory facilitates an understanding of the basic physical mechanisms at work in a fluid system while retaining the ability to reproduce a surprisingly large array of atmospheric and oceanic phenomena. The model presented here extends the domain of quasi-geostrophic theory while retaining the simplicity. The fully spherical version of this quasi-balanced theory is derived by partitioning the flow into nondivergent and irrotational components rather than geostrophic and ageostrophic components. The potential vorticity invertibility relation can be solved analytically by using spheroidal harmonic transforms, which improves the usefulness of the theory. Except for sectoral harmonics of low zonal wavenumber, the quasi-balanced Rossby-Haurwitz frequencies from our model agree very well with the frequencies calculated by Longuet-Higgins from the primitive equations. A pseudo-spectral model using spherical harmonic basis functions has been developed to explore various applications of this system. Among these are the dispersion of Rossby-Haurwitz waves at varying Lamb’s parameter, spherical quasi-balanced turbulence including the emergence of zonal jets, and a generalization of the anisotropic Rhines length to three-dimensional wavenumber space. We are also examining the differing behavior between Rossby wave dispersion in the equatorial and polar regions.
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.
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.
Veringa, Irena K; de Bruin, Esther I; Bardacke, Nancy; Duncan, Larissa G; van Steensel, Francisca J A; Dirksen, Carmen D; Bögels, Susan M
2016-11-07
Approximately 25 % of pregnant women suffer from a high level of Fear of Childbirth (FoC), as assessed by the Wijma Delivery Expectancy Questionnaire (W-DEQ-A, score ≥66). FoC negatively affects pregnant women's mental health and adaptation to the perinatal period. Mindfulness-Based Childbirth and Parenting (MBCP) seems to be potentially effective in decreasing pregnancy-related anxiety and stress. We propose a theoretical model of Avoidance and Participation in Pregnancy, Birth and the Postpartum Period in order to explore FoC and to evaluate the underlying mechanisms of change of MBCP. The 'I've Changed My Mind' study is a quasi-experimental controlled trial among 128 pregnant women (week 16-26) with a high level of FoC, and their partners. Women will be allocated to MBCP (intervention group) or to Fear of Childbirth Consultation (FoCC; comparison group). Primary outcomes are FoC, labour pain, and willingness to accept obstetrical interventions. Secondary outcomes are anxiety, depression, general stress, parental stress, quality of life, sleep quality, fatigue, satisfaction with childbirth, birth outcome, breastfeeding self-efficacy and cost-effectiveness. The total study duration for women is six months with four assessment waves: pre- and post-intervention, following the birth and closing the maternity leave period. Given the high prevalence and severe negative impact of FoC this study can be of major importance if statistically and clinically meaningful benefits are found. Among the strengths of this study are the clinical-based experimental design, the extensive cognitive-emotional and behavioural measurements in pregnant women and their partners during the entire perinatal period, and the representativeness of study sample as well as generalizability of the study's results. The complex and innovative measurements of FoC in this study are an important strength in clinical research on FoC not only in pregnant women but also in their partners. Dutch Trial
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.
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.
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.
Statistical fluctuations of radiation in quasi-Cherenkov generators
NASA Astrophysics Data System (ADS)
Anishchenko, S. V.; Baryshevsky, V. G.
2017-07-01
In a nonstationary (self-modulation) regime, terahertz quasi-Cherenkov generators can operate at MHz-GHz repetition rates and megawatt power levels. Shot noise, intrinsic to electron beams, is the cause of statistical fluctuations of radiation in the generators. The shot-noise related spread of instability growth time imposes appreciable limitations on the possibility of coherent summation of electromagnetic oscillations from several quasi-Cherenkov generators operating in a nonstationary mode.
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.
Petrov, S.V.; Katsov, K.M.
1995-05-01
A method for constructing the effective rotational Hamiltonian for an isolated vibrational state directly from the classical vibrational-rotational Hamiltonian function, without invoking the experimental data on rotational spectra, is suggested. Test calculations are carried out for diatomic molecules. The relative accuracy of the rotational-level calculations is on the order of 10{sup -5}. 17 refs., 2 tabs.
NASA Astrophysics Data System (ADS)
Wood, K. S.; Ftaclas, C.; Kearney, M.
1988-01-01
Some quasi-periodic oscillation models are based on accretion onto a neutron star possessing a weak magnetic field. These models successfully explain many aspects of the observed oscillations, yet they acquire a rapidly rotating neutron star possessing a magnetic field that can channel accretion flow, leading to uneven heating of the star surface. This is similar to what happens in accreting binary pulsars, yet modulation of X-ray flux at the spin period has not been observed. It is suggested that gravitational deflection of photons can be very effective in reducing this pulsed flux under exactly the conditions required in these QPO models. Gravitational effects appear to be essential to reducing the pulsed flux to levels consistent with observation. Implications for QPO observations and for the theory of binary pulsars are discussed.
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).
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.
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.
Theusinger, Oliver M; Schröder, Carsten M; Eismon, Jennifer; Emmert, Maximilian Y; Seifert, Burkhardt; Spahn, Donat R; Baulig, Werner
2013-08-01
The aim of this study was to determine the association between standard laboratory tests, coagulation factor concentrations, and Rotation Thromboelastometry (ROTEM® delta, TEM® International GmbH, Munich, Germany) in patients undergoing major surgery with hemorrhage. In 45 patient's fibrinogen, factor VIII, factor XIII, International Normalized Ratio (INR), activated partial thromboplastin time (aPTT), thrombin time, hemoglobin, leukocytes, and platelet count were simultaneously measured intraoperatively with ROTEM (EXTEM, INTEM, FIBTEM, APTEM) measurements. ROTEM parameters were: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), and α-angle. Demographic and laboratory data were expressed as mean ± SD and median [range]; nonparametric Spearman rank correlations and multiple linear regressions were performed; P-values ≤0.003 were considered significant. Significant correlations (P ≤ 0.003) were found for CFT, α-angle, and MCF, in EXTEM, INTEM, and APTEM with platelets, INR, and fibrinogen. Factor VIII (18 measurements) showed a strong correlation (r ≥ 0.7 or r ≤ -0.7; all P ≤ 0.003) with MCF, CFT, and α-angle of EXTEM, INTEM, MCF of FIBTEM excluding CT of EXTEM, INTEM, FIBTEM and strong significant correlation for α-angle of APTEM and moderate for CFT and MCF of APTEM. A significant moderate to strong correlation of factor XIII with MCF of EXTEM, INTEM, FIBTEM, and APTEM was found. Hemoglobin was moderately correlated (r = 0.3-0.7 or r = -0.3 to -0.7) with MCF in APTEM (P = 0.003). A moderate to strong correlation of the standard coagulation tests with all ROTEM parameters was found, in particular the CT. The aPTT correlated significantly moderate to strong with CT, CFT, α-angle, and MCF of INTEM. However, multiple linear regressions were not able to show an influence of INR on ROTEM parameters except for APTEM-MCF. A significant impact of the aPTT on INTEM-CT was found. EXTEM, INTEM, and APTEM are significantly influenced
Submillimeter Quasi-periodic Oscillations in Magnetically Choked Accretion Flow Models of SgrA*
NASA Astrophysics Data System (ADS)
Shcherbakov, Roman V.; McKinney, Jonathan C.
2013-09-01
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 10σ-30σ and high-quality factors Q ≈ 5. The oscillation period T ≈ 100 M ≈ 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°, 37°, and 80°. 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.
SUBMILLIMETER QUASI-PERIODIC OSCILLATIONS IN MAGNETICALLY CHOKED ACCRETION FLOW MODELS OF SgrA*
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.
Quasi-linear blocks forced by orography in a hemispheric, quasi-geostrophic barotropic model
NASA Technical Reports Server (NTRS)
Roads, J. O.
1981-01-01
Stationary linear perturbation responses to Northern Hemisphere orography are calculated in a quasi-geostrophic barotropic model in solid-body rotation. The stationary mountain torque induced by these perturbations is then used to construct graphical solutions to the steady-state wave, mean-flow interaction problem. It is shown that multiple solutions exist in the system and are near either the forcing equilibrium of the zonal forcing or near the resonance points in the system. Some of these near-resonance solutions have block-like configurations with a confluence zone upstream from a large-amplitude structure consisting of a high at high latitudes and a low at low latitudes. These block-like configurations are shown to be near stable solutions of the system. Time-dependent calculations show that the initial state and the zonal forcing equilibrium are important in determining the long-term time evolution of the system.
Quasi-classical trajectories study of Ne79Br2(B) vibrational predissociation.
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.
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…
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…
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.
Quasi-biennial oscillation above 10 mb
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.
Quasi-biennial oscillation above 10 mb
NASA Technical Reports Server (NTRS)
Baldwin, Mark P.; Dunkerton, Timothy J.
1991-01-01
It is shown that the quasi-biennial oscillation of the equatorial lower stratosphere was correlated with mean zonal wind in the upper stratosphere, 1979-1990. Correlations were positive near 60 deg N and 30 deg 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 deg S and 62 deg N, due to strong coupling between tropical and extratropical flow at upper levels.
Vortex structures of rotating Bose-Einstein condensates in an anisotropic harmonic potential
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.
Relative equilibria with holes for the surface quasi-geostrophic equations
NASA Astrophysics Data System (ADS)
Renault, Coralie
2017-07-01
We study the existence of doubly connected rotating patches for the inviscid surface quasi-geostrophic equation left open by de la Hoz, Hassainia and Hmidi in 2016 in [10]. By using the approach proposed in 2016 by Castro, Córdoba and Gomez-Serrano in [4] we also prove that close to the annulus the boundaries are actually analytic curves.
Quasi-classical Trajectory Study of Ba+HI→BaI+H Reaction
NASA Astrophysics Data System (ADS)
Atasie, V. N.
2010-10-01
The quasi-classical trajectory calculations based on extended London-Eyring-Polanyi-Sato potential energy surface have been used to study the reaction of Ba+HI→BaI+H system. The rotational, vibrational, translational, and angular distributions of the product BaI have been calculated. The calculated results are in good agreement with the experimental ones.
KEPLER RAPIDLY ROTATING GIANT STARS
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.
Axial rotation in Parkinson's disease
Vaugoyeau, M; Viallet, F; Aurenty, R; Assaiante, C; Mesure, S; Massion, J
2006-01-01
Aims To investigate the ability of patients with Parkinson's disease to perform a rotation around the longitudinal axis of the body. Three questions were raised. Is body rotation impaired in Parkinson's disease? Is there a level of the kinematic chain from the head to the foot at which the impairment is more severe? Is the deficit related to the general slowness of movement in Parkinson's disease? Methods Kinematic data were recorded. The temporal organisation of body rotation during gait initiation was analysed in 10 patients with Parkinson's disease, who were all at an advanced stage of the disease and had all experienced falls and freezing during their daily life, and in five controls. The latency of the onset of the rotation of each segment was measured by taking the onset of the postural phase of step initiation as reference value. Locomotor variables were also analysed. Results Body rotation was found to be impaired in patients with Parkinson's disease, as the delay in the onset of the rotation of each segment is greater than that in controls. Moreover, a specific uncoupling in the onset of shoulder and pelvis segment rotation was seen in patients. This impairment of rotation is not related only to the general slowness of movements. Conclusion Patients with Parkinson's disease were found to have an impairment of posturo‐kinetic coordination and impaired capacity to exert appropriate ground reaction forces to orient the pelvis in space. PMID:16574736
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
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
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.
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
Calkins, Michael A; Julien, Keith; Marti, Philippe
2015-03-08
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.
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
The beat frequency model for QPOs. [Quasi-Periodic-Oscillations
NASA Technical Reports Server (NTRS)
Shaham, Jacob
1987-01-01
The quasi-periodic oscillation (QPO) phenomenon has come to pose increasingly complex problems as sources have been discovered; these currently number 12, of which at least seven are X-ray binaries. The beat-frequency model (BFM), originally devised to characterize the first and simplest of the QPOs, GX5-1, is presently discussed with a view to its assumptions and applicability to other QPOs. The most important problem with the BFM is identified as the assumption that the neutron star involved rotates at an angular frequency of the order, in the case of GX5-1, of 10 msec.
Spatial Compounding Technique to Obtain Rotation Elastogram: A Feasibility Study.
Kothawala, AliArshad; Chandramoorthi, Sowmiya; Reddy, N Ravi Kiran; Thittai, Arun Kumar
2017-06-01
The perception of stiffness and slipperiness of a breast mass on palpation is used by physicians to assess the level of suspicion of a lesion as being malignant or benign. However, most current ultrasound elastography imaging methods provide only stiffness-related information. There is no existing approach that provides information about the local rigid body rotation undergone by only a loosely bonded, asymmetrically oriented lesion subjected to a small quasi-static compression. The inherent poor lateral resolution in ultrasound imaging poses a limitation in estimating the local rigid body rotation. Several techniques have been reported in the literature to improve the lateral resolution in ultrasound imaging, and among them is spatial compounding. In this study, we explore the feasibility of obtaining better-quality rotation elastograms with spatial compounding through simulations using Field II and experiments on tissue-mimicking phantoms. The phantom was subjected to axial compression (∼1%-2%) from the top, and the angular axial and lateral displacement estimates were obtained using a multilevel 2-D displacement tracking algorithm at different insonification angles. A rotation elastogram (RE) was obtained by taking half of the difference between the lateral gradient of the axial displacement estimates and the axial gradient of the lateral displacement estimates. Contrast-to-noise ratio was used to quantify the improvements in quality of RE. Contrast-to-noise ratio values were calculated by varying the maximum steering angle and the incremental angle, and its effects on RE quality were evaluated. Both simulation and experimental results corroborated and indicated a significant improvement in the quality of RE using compounding technique. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.
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.
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…
Large-scale quasi-geostrophic magnetohydrodynamics
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.
Pseudoparalysis: the importance of rotator cable integrity.
Denard, Patrick J; Koo, Samuel S; Murena, Luigi; Burkhart, Stephen S
2012-09-01
The purpose of this study was to clinically examine the relationship between rotator cable integrity and the presence of pseudoparalysis. A retrospective review was performed of a consecutive series of arthroscopic repairs of massive rotator cuff tears performed between January 2007 and June 2009. A total of 127 massive tears were identified. Group 1 comprised 24 patients with preoperative pseudoparalysis. Group 2 comprised 97 patients (103 repairs) with active forward flexion more than 90°. In group I, no patient maintained integrity of both rotator cable attachments; 1 rotator cable attachment was disrupted in 45.8% of cases; and both rotator cable attachments were disrupted in 54.2% of cases. In group II, both rotator cable attachments were intact in 22.3% of cases; 1 rotator cable attachment was disrupted in 62.1% of cases; and both rotator cable attachments were disrupted in 15.5% of cases. The difference in the distribution of cable attachments between the 2 groups was statistically significant (P<.001). Overall, preoperative pseudoparalysis predicted a disruption of both rotator cables with 88.8% specificity, 44.8% sensitivity, and 77.8% accuracy. Pseudoparalysis requires the disruption of at least 1 rotator cable attachment. This study reinforces the concept of rotator cable integrity and the ability of patients to maintain forward flexion above shoulder level and highlights the importance of reinforcing the rotator cable attachments in the repair of massive rotator cuff tears. Copyright 2012, SLACK Incorporated.
Cylindrical quasi-Gaussian beams.
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.
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.
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.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Li, Jian; Li, Lingyun; Jin, Haifei; Li, Ruifan
2013-11-01
Environmental noise is inevitable in non-isolated systems. It is, therefore, necessary to analyze the security of the “Ping-Pong” protocol in a noisy environment. An excellent model for collective-rotation noise is introduced, and information theoretical methods are applied to analyze the security of this protocol. If noise level ε is lower than 11%, an eavesdropper can gain some, but not all, information freely without being detected. Otherwise, the protocol becomes insecure. We conclude that the use of ‘Ping-Pong’ protocol as a quantum secure direct communication (QSDC) protocol is quasi-secure, as declared by the original author when ε⩽11%.
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.
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.
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.
Hu, Li-Hong; Wang, X.; Perry, D.S.
1996-12-31
Jet-cooled absorption spectra of the C-H stretching bands of methanol have been recorded between 2965 and 3027 cm{sup -1} on two different molecular beam machines. In both cases, a color-center laser pumped by {approximately}1.6 W from a krypton ion laser at 647 nm was used to generate 8-9 mW of tunable IR radiation. The first spectrum between 2977-3027 cm{sup -1} was recorded in direct absorption with a 2 x 0.01 cm slit nozzle. The molecular rotational temperature was {approximately}17 K, and the linewidth was {approximately}75 MHz due to residual Doppler spread. Baseline subtraction was employed to suppress laser intensity fluctuations. Frequency calibration was accomplished by simultaneously recording absorption lines of ethylene and the transmission fringes of a vacuum-spaced 150 MHz-marker etalon. The second spectrum between 2965-3627 cm{sup -1} was recorded on a molecular-beam optothermal spectrometer. A mixture of a few percent methanol in He carrier was introduced to the beam chamber through a 60-{mu}m pinhole nozzle with {approximately}1atm backing pressure, giving a rotational temperature of {approximately}10 K. The beam was focused onto a He-cooled bolometer using quadrupole focusing in the flight chamber between the skimmer and the detector. In a few pathological regions, H{sub 2}O absorption completely obscured the methanol spectrum and spoiled control of the laser scan. Calibration traces were recorded to minimize errors due to gaps and drifts. On a given day the calibration interferometer drift was typically less than {approximately}10 MHz, defining the overall precision. Separations of close lines in a single scan should have precision better than 1 MHz. The two spectra were combined for analysis, with the straight absorption spectrum giving particularly nice and easily recognizable spectral patterns.
NASA Astrophysics Data System (ADS)
Al-Shenqiti, A.; Oldham, J.
2003-12-01
The purpose of this study was to investigate the efficacy of LLLT in the treatment of trigger points (TrPs) that are associated with rotator cuff tendonitis. A double-blind randomized controlled trail was conducted. Sixty patients were randomly allocated to one of two groups: sham or laser therapy. The laser (Excel, Omega Universal Technologies Ltd, London, UK) parameters used were a wavelength of 820 nm, a power output of 100 mW, a frequency of 5000 Hz (modulated) and energy density of 32 J/cm2. The two groups received a course of 12 treatment sessions for four weeks (3 sessions per week). Pain, functional activities (as measured using the Shoulder Pain and Disability Index, SPADI), pressure pain threshold (PPT) and range of motion (ROM) were assessed pre and post treatment, with a three month follow-up assessment. Significant improvements in pain (p < 0.001) were observed for the laser group (6 cm median improvement on a 10 cm VAS) compared to the sham group (2 cm median improvement) immediately post treatment. The improvements in the laser group continued post treatment with a 7 cm median improvement observed at three month follow-up. Similar between group differences were observed for ROM (p < 0.01), functional activities (p <= 0.001) and PPT (p <= 0.05). The findings of the current study suggested that LLLT is effective in treating patients with TrPs associated with rotator cuff tendonitis, when using the parameters described. However, the mechanism of its action is not yet clear, and will require further investigation.
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.
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.
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.
Quasi-Axially Symmetric Stellarators with 3 Field Periods
NASA Astrophysics Data System (ADS)
Garabedian, Paul; Ku, Long-Poe
1998-11-01
Compact hybrid configurations with 2 field periods have been studied recently as candidates for a proof of principle experiment at PPPL, cf. A. Reiman et al., Physics design of a high beta quasi-axially symmetric stellarator, J. Plas. Fus. Res. SERIES 1, 429(1998). This enterprise has led us to the discovery of a family of quasi-axially symmetric stellarators with 3 field periods that seem to have significant advantages, although their aspect ratios are a little larger. They have reversed shear and perform better in a local analysis of ballooning modes. Nonlinear equilibrium and stability calculations predict that the average beta limit may be as high as 6% if the bootstrap current turns out to be as big as that expected in comparable tokamaks. The concept relies on a combination of helical fields and bootstrap current to achieve adequate rotational transform at low aspect ratio. A detailed manuscript describing some of this work will be published soon, cf. P.R. Garabedian, Quasi-axially symmetric stellarators, Proc. Natl. Acad. Sci. USA 95 (1998).
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.
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
Visual perception of axes of head rotation
Arnoldussen, D. M.; Goossens, J.; van den Berg, A. V.
2013-01-01
Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. (1) Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit. We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow's rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals. (2) Do transformed visual self-rotation signals reflect the arrangement of the semi-circular canals (SCC)? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those Blood oxygenated level-dependent (BOLD) signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes. (3) We investigated if subject's sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is
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.
NASA Astrophysics Data System (ADS)
Takiguchi, Futoshi; Tahara, Hirokazu; Kagaya, Yoichi; Yoshikawa, Takao
A quasi-steady magnetoplasmadynamic (MPD) arcjet with applied magnetic fields was studied to clarify the influence of axial magnetic fields on the thruster performance and discharge feature. Pulsed axial magnetic fields were applied by a few-turn coil, which was connected with a pulse forming network independent of the main discharge circuit. An increase in axial intensity raised the discharge voltage at the same discharge current below the limiting current. The thrust characteristics for mixture of N2+2H2 and H2 showed that there were the optimum axial field intensities with which the maximum thrusts were achieved. The discharges for most of discharge current levels occurred more upstream as axial field intensity increased. It was inferred that these effects of axial magnetic fields on the thruster performance and the arc feature were due to rotating motion of -J(sub r) x B(sub z), that is, swirl acceleration and enhanced thermalization.
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.
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).
Quasi-steady plasma accelerators
NASA Technical Reports Server (NTRS)
Ducati, A. C.
1972-01-01
Results are reported from a continued study of MPD thrusters operating in the quasi-steady mode and using electrode vapor as the propellant. Testing methods were refined, and performance data is now available for a fairly wide range of thruster geometries. Performance was found to be strongly dependent on thruster geometry, with some designs showing approximately twice the efficiency obtained during the preceding contract period. The radial clearance between electrodes, the attachment point of the arc on the cathode, and the electrical resistance of the electrodes appear to be important design variables.
Conservative treatment of rotator cuff injuries.
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.
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).
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.
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
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.
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.
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.
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.
Understanding the rotation of coronal holes
NASA Technical Reports Server (NTRS)
Wang, Y.-M.; Sheeley, N. R., Jr.
1993-01-01
In an earlier study we found that the rotation of coronal holes could be understood on the basis of a nearly current-free coronal field, with the holes representing open magnetic regions. In this paper we illustrate the model by focusing on the case of CH1, the rigidly rotating boot-shaped hole observed by Skylab. We show that the interaction between the polar fields and the flux associated with active regions produces distortions in the coronal field configuration and thus in the polar-hole boundaries; these distortions corotate with the perturbing nonaxisymmetric flux. In the case of CH1, positive-polarity field lines in the northern hemisphere 'collided' with like-polarity field lines fanning out from a decaying active region complex located just below the equator, producing a midlatitude corridor of open field lines rotating at the rate of the active region complex. Sheared coronal holes result when nonaxisymmetric flux is present at high latitudes, or equivalently, when the photospheric neutral line extends to high latitudes. We demonstrate how a small active region, rotating at the local photospheric rate, can drift through a rigidly rotating hole like CH1. Finally, we discuss the role of field-line reconnection in maintaining a quasi-potential coronal configuration.
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.
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.
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.
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.
A quasi-dense matching approach and its calibration application with Internet photos.
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.
... stretch (anterior shoulder stretch) Anterior shoulder stretch - towel Pendulum exercise Wall stretches Exercises to strengthen your shoulder: ... rotation with band Internal rotation with band Isometric Pendulum exercise Shoulder blade retraction with tubing Shoulder blade ...
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.)
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.
Hydrogen rotation-vibration oscillator
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)
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.
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.
Minimax discrimination of quasi-Bell states
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.
Quasi-particles at finite chemical potential
Gardim, F. G.; Steffens, F. M.
2010-07-27
We present in this work the thermodynamic consistent quasi-particle model at finite chemical potential, to describe the Quark Gluon Plasma composed of two light quarks and gluons. The quasi-particle general solution will be discussed, and comparison with perturbative QCD and lattice data will be shown.
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…
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…
Trirotron: triode rotating beam radio frequency amplifier
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.
Rotational spectroscopy with an optical centrifuge.
Korobenko, Aleksey; Milner, Alexander A; Hepburn, John W; Milner, Valery
2014-03-07
We demonstrate a new spectroscopic method for studying electronic transitions in molecules with extremely broad range of angular momentum. We employ an optical centrifuge to create narrow rotational wave packets in the ground electronic state of (16)O2. Using the technique of resonance-enhanced multi-photon ionization, we record the spectrum of multiple ro-vibrational transitions between X(3)Σg(-) and C(3)Πg electronic manifolds of oxygen. Direct control of rotational excitation, extending to rotational quantum numbers as high as N ≳ 120, enables us to interpret the complex structure of rotational spectra of C(3)Πg beyond thermally accessible levels.
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.
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…
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…
Quasi parton distributions and the gradient flow
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
Quasi-Freestanding multilayer graphene films on the carbon face of SiC
Siegel, D. A.; Hwang, C. G.; Fedorov, A. V.; Lanzara, A.
2010-06-30
The electronic band structure of as-grown and doped graphene grown on the carbon face of SiC is studied by high-resolution angle-resolved photoemission spectroscopy, where we observe both rotations between adjacent layers and AB-stacking. The band structure of quasi-freestanding AB-bilayers is directly compared with bilayer graphene grown on the Si-face of SiC to study the impact of the substrate on the electronic properties of epitaxial graphene. Our results show that the C-face films are nearly freestanding from an electronic point of view, due to the rotations between graphene layers.
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.
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.
Quasi-local conserved charges in Lorenz-diffeomorphism covariant theory of gravity
NASA Astrophysics Data System (ADS)
Adami, H.; Setare, M. R.
2016-04-01
In this paper, using the combined Lorenz-diffeomorphism symmetry, we find a general formula for the quasi-local conserved charge of the covariant gravity theories in a first order formalism of gravity. We simplify the general formula for the Lovelock theory of gravity. Afterwards, we apply the obtained formula on BHT gravity to obtain the energy and angular momentum of the rotating OTT black hole solution in the context of this theory.
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.
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.
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.
Weighing the black hole via quasi-local energy
NASA Astrophysics Data System (ADS)
Ha, Yuan K.
2017-08-01
We set to weigh the black holes at their event horizons in various spacetimes and obtain masses which are substantially higher than their asymptotic values. In each case, the horizon mass of a Schwarzschild, Reissner-Nordström, or Kerr black hole is found to be twice the irreducible mass observed at infinity. The irreducible mass does not contain electrostatic or rotational energy, leading to the inescapable conclusion that particles with electric charges and spins cannot exist inside a black hole. This is proposed as the External Energy Paradigm. A higher mass at the event horizon and its neighborhood is obligatory for the release of gravitational waves in binary black hole merging. We describe how these horizon mass values are obtained in the quasi-local energy approach and applied to the black holes of the first gravitational waves GW150914.
Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators
L.P. Ku and A.H. Boozer
2010-09-10
Characteristics of modular coils for quasi-axisymmetric stellarators that are related to the plasma aspect ratio, number of field periods and rotational transform have been examined systematically. It is observed that, for a given plasma aspect ratio, the coil complexity tends to increase with the increased number of field periods. For a given number of field periods, the toroidal excursion of coil winding is reduced as the plasma aspect ratio is increased. It is also clear that the larger the coil-plasma separation is, the more complex the coils become. It is further demonstrated that it is possible to use other types of coils to complement modular coils to improve both the physics and the modular coil characteristics.
Quintic quasi-topological gravity
NASA Astrophysics Data System (ADS)
Cisterna, Adolfo; Guajardo, Luis; Hassaïne, Mokhtar; Oliva, Julio
2017-04-01
We construct a quintic quasi-topological gravity in five dimensions, i.e. a theory with a Lagrangian containing {\\mathcal{R}}^5 terms and whose field equations are of second order on spherically (hyperbolic or planar) symmetric spacetimes. These theories have recently received attention since when formulated on asymptotically AdS spacetimes might provide for gravity duals of a broad class of CFTs. For simplicity we focus on five dimensions. We show that this theory fulfils a Birkhoff's Theorem as it is the case in Lovelock gravity and therefore, for generic values of the couplings, there is no s-wave propagating mode. We prove that the spherically symmetric solution is determined by a quintic algebraic polynomial equation which resembles Wheeler's polynomial of Lovelock gravity. For the black hole solutions we compute the temperature, mass and entropy and show that the first law of black holes thermodynamics is fulfilled. Besides of being of fourth order in general, we show that the field equations, when linearized around AdS are of second order, and therefore the theory does not propagate ghosts around this background. Besides the class of theories originally introduced in arXiv:1003.4773, the general geometric structure of these Lagrangians remains an open problem.
Quasi-Gaussian electromagnetic beams
NASA Astrophysics Data System (ADS)
Mitri, F. G.
2013-03-01
A class of Maxwellian beams, which is an exact solution of the vector wave equation (Helmholtz equation) and Maxwell's equations, is introduced. The solution, termed a quasi-Gaussian electromagnetic (EM) beam, is formed from a superposition of sources and sinks with complex coordinates, and is characterized by an arbitrary waist w0 and a diffraction convergence length known as the Rayleigh range zR. An attractive feature of this beam is the description of strongly focused (or strongly divergent) EM-optical wave fields for kw0≤1, where k is the wave number. A vector wave analysis is developed to determine and compute the spatial Cartesian components of the electric and magnetic fields (valid in the near field and the far field) stemming from Maxwell's vector equations and the Lorenz gauge condition, with particular emphasis on the parameter kw0 and the polarization states of the vector potentials used to derive the EM field's components. The results are potentially useful in the study of the axial and/or arbitrary wave scattering, radiation force, and torque in lasers operating with strongly focused (or strongly divergent) beams for particle manipulation in optical tweezers and imaging applications.
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.
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.
Rotational dynamics of endohedral C60 fullerene complexes
NASA Astrophysics Data System (ADS)
Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.
1997-11-01
The structure of the rotational low-energy eigenvalue spectrum and eigenfunction of endohedral C60 fullerene complexes is investigated. The selected systems are Li+@C60, Na+@C60, CO@C60, and LiH@C60. The eigenvalue spectra may be classified basically into two types. Below some critical degree of anisotropy in the guest-cage interaction the spectrum looks rather simple, and similar to that of an effective diatomic molecule. For high enough anisotropic interactions, the low-energy eigenvalue spectrum is characterized by a double-band structure: a ground band localized around the fullerene hexagon centers, and an excited band embedded in a rotational quasi-continuum and localized at the unstable equilibrium regions around the fullerene pentagon centers. The cage rotation makes the transition from one type to the other much sharper type. Rotation dipole and Raman spectra are assigned in terms of these two types of structure in the eigenvalue spectrum.
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.
Katsikadakos, D; Hardalupas, Y; Taylor, A M K P; Hunt, P A
2012-07-21
Hydrogen abstraction reactions by the methyl radical from n-butanol have been investigated at the ROCBS-QB3 level of theory. Reaction energies and product geometries for the most stable conformer of n-butanol (ROH) have been computed, the reaction energies order α < γ < β < δ < OH. The preference for n-butane to favour H-abstraction at C(β) and C(γ) while, in contrast, n-butanol favours radical reactions at the C(α) carbon is rationalised. Transition state (TS) barriers and geometries for the most stable conformer of n-butanol are presented, and discussed with respect to the Hammond postulate. The reaction barriers order as α < OH < γ < β < δ. This relative ordering is not consistent with product radical stability, C-H bond dissociation energies or previous studies using O[combining dot above]H and HO[combining dot above](2) radicals. We provide a molecular orbital based rationalisation for this ordering and answer two related questions: Why is the γ-channel more stable than the β-channel? Why do the two C(γ)-H H-abstraction TS differ in energy? The method and basis set dependence of the TS barriers is investigated. The Boltzmann probability distribution for the n-butanol conformers suggests that low energy conformers are present in approximately equal proportions to the most stable conformer at combustion temperatures where ĊH(3) radicals are present. Thus, the relative significance of the various H-abstraction channels has been assessed for a selection of higher energy conformers (ROH'). Key results include finding that higher energy n-butanol conformers (E(ROH') > E(ROH)) can generate lower energy product radicals, E(ROH') < E(ROH). Moreover, higher energy conformers can also have a globally competitive TS energy for H-abstraction.
Cylindrical rotating triboelectric nanogenerator.
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.
Influence of solar UV irradiance on quasi-biennial oscillations in the Earth's atmosphere
NASA Astrophysics Data System (ADS)
Gabis, I.; Troshichev, O.
2004-01-01
A study of relationships between variations in the solar ultraviolet (UV) irradiance and quasi-biennial oscillations (QBO) of mean zonal wind in the Earth's equatorial stratosphere has been carried out with use of the composite MgII index as a proxy for the solar UV irradiance. The middle-term changes in the UV-irradiation have been separated after removing the long-term (≈11 years) and short-term (≈27 days) variations. The results of the analysis show that the average UV irradiance tends to be higher for east QBO-phase and lower for west phase. The detail analysis of rotation in the stratospheric wind profiles reveals that the quiet periods alternate with active periods, characterizing by strong disturbing winds. Some of these stages occur only in certain seasons, which implies that they are guided by the internal atmospheric mechanisms. Duration of active stages can be affected by level of the UV irradiance. Conclusion is made that variability of the QBO-phase duration in the equatorial stratosphere can be interpreted if influence of the solar UV medium-term variation on basic stratospheric processes is taken into account.
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.
NASA Astrophysics Data System (ADS)
Yang, Chi Ming
2004-05-01
Upon the covalent-bonding hybrid of the nitrogen atoms (sp2) taken as a measure for the structural regularity in the four RNA nucleobases, it has been identified that the 20 amino acid coalescence follows a cooperative vector-in-space addition principle based on the spherical and rotational symmetry of a quasi-28-gon (quasi-icosikaioctagon) construction, with two suggested cooperative evolutionary axes within the genetic code.
Quantum and quasi-classical calculations for the S+ + H2(v, j) →SH+(v′, j′)+H reactive collisions
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
NASA Astrophysics Data System (ADS)
Van Hoolst, Tim; Baland, Rose-Marie; Trinh, Antony; Coyette, Alexis; Yseboodt, Marie
2017-04-01
The rotation rate of Ganymede, the largest satellite of Jupiter, is on average equal to its orbital mean motion but cannot be constant on orbital time scale as a result of the gravitational torque exerted by Jupiter on the moon. Here we discuss small deviations from the average rotation rate, evaluate polar motion, and discuss Ganymede's obliquity. We examine different time scales and assess the potential of using rotation as probes of the interior structure. The ESA JUICE (JUpiter ICy moons Explorer) mission will accurately measure the rotation of Ganymede during its orbital phase around the satellite starting in 2032. We report on different theoretical aspects of the rotation for realistic models of the interior of Ganymede, include tidal deformations and take into account the low-degree gravity field and topography of Ganymede. We assess the advantages of a joint use of rotation and tides to constrain the satellite's interior structure, in particular its ice shell and ocean.
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.
Gupta, Vivek Vardhan; Kaur, Amanlo; Singla, Ruku; Chitkara, Neha; Bajaj, Krushnan V.; Rawat, H.C.L
2014-01-01
Background: Distraction techniques are often provided by nurses, parents or child life specialists and help in pain alleviation during procedures. The use of non pharmacological procedures to cope with pain behaviour is less costly and most of these procedures can be administered by a nurse. Hence, the aim of the present study was to assess and compare the analgesic effect of holding the child by a family member versus holding the child by a family member along with an animation distraction intervention on the level of pain perception during venipuncture in children up to seven years of age. Materials and Methods: Purposive sampling technique was used to select 70 children admitted in paediatric ward of Guru Gobind Singh Medical Hospital, Faridkot, 35 children in each group viz. Group 1(child held by family member during venipuncture) and Group 2 (child held by family member along with an animation distraction during venipuncture) and video clippings were made for each subject in both groups. Standardized FLACC pain scale was used to assess the level of pain during venipuncture by seeing the video clips of procedure in both groups. Results: Findings revealed that the mean pain score of Group 1 was 3.86 and that of Group 2 was 2.43. Findings revealed that in Group 1 majority 31(88.57%) got severe pain and none remained relaxed during venipuncture whereas in Group 2 majority 10(28.58%) got moderate pain, 09(25.71%) remained relaxed and only 07(20%) got severe pain. The comparison of mean pain score of both groups was checked statistically by computing independent t-test and the value of t comes out to be 7.199 with p-value 0.000*** which was found to be highly significant. Conclusion: The study concluded that when during painful procedures like venipuncture if children are given any non-pharmacological intervention like animated distraction along with their family member it helps in managing the pain. In other words, it distracts/diverts the child’s attention from
Gupta, Harsh Vardhan; Gupta, Vivek Vardhan; Kaur, Amanlo; Singla, Ruku; Chitkara, Neha; Bajaj, Krushnan V; Rawat, H C L
2014-08-01
Distraction techniques are often provided by nurses, parents or child life specialists and help in pain alleviation during procedures. The use of non pharmacological procedures to cope with pain behaviour is less costly and most of these procedures can be administered by a nurse. Hence, the aim of the present study was to assess and compare the analgesic effect of holding the child by a family member versus holding the child by a family member along with an animation distraction intervention on the level of pain perception during venipuncture in children up to seven years of age. Purposive sampling technique was used to select 70 children admitted in paediatric ward of Guru Gobind Singh Medical Hospital, Faridkot, 35 children in each group viz. Group 1(child held by family member during venipuncture) and Group 2 (child held by family member along with an animation distraction during venipuncture) and video clippings were made for each subject in both groups. Standardized FLACC pain scale was used to assess the level of pain during venipuncture by seeing the video clips of procedure in both groups. Findings revealed that the mean pain score of Group 1 was 3.86 and that of Group 2 was 2.43. Findings revealed that in Group 1 majority 31(88.57%) got severe pain and none remained relaxed during venipuncture whereas in Group 2 majority 10(28.58%) got moderate pain, 09(25.71%) remained relaxed and only 07(20%) got severe pain. The comparison of mean pain score of both groups was checked statistically by computing independent t-test and the value of t comes out to be 7.199 with p-value 0.000*** which was found to be highly significant. The study concluded that when during painful procedures like venipuncture if children are given any non-pharmacological intervention like animated distraction along with their family member it helps in managing the pain. In other words, it distracts/diverts the child's attention from pain and results in better cooperation of child during
Quasi-random array imaging collimator
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.
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 $.
Quasi-adiabatic transport in Mercury's magnetotail
NASA Astrophysics Data System (ADS)
Delcourt, Dominique; Malova, Helmi; Zelenyi, Lev
2017-04-01
MESSENGER observations have revealed that the magnetotail of Mercury is fairly dynamical, possibly subjected to series of magnetic field line dipolarization on time scales of a few seconds. Because of the sharp reversal of the magnetic field, ions may not travel adiabatically in this region of space, and their behavior can be organized according to different categories. Among these categories, quasi-adiabatic (Speiser) ions are such that they experience negligible net change of magnetic moment upon crossing of the field reversal and can thus travel back to low altitudes. We examine the robustness of this quasi-adiabatic behavior during magnetic field line dipolarization where ions are subjected to a large induced electric field. We demonstrate that, although this surging electric field possibly yields substantial nonadiabatic heating, quasi-adiabaticity is robust for ions with velocities larger than the peak ExB drift speed, a behavior that we refer to as "strong" quasi-adiabaticity (as opposed to "weak" quasi-adiabaticity that is violated during dipolarization). We show that the impulsive energization of such quasi-adiabatic ions during dipolarization events can lead to prominent energy-time dispersion structures at low altitudes.
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.
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
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.
NASA Astrophysics Data System (ADS)
Pousse, Alexandre; Robutel, Philippe; Vienne, Alain
2017-08-01
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.
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.
Philip E. Pope; Jeffery O. Dawson
1989-01-01
Short-rotation plantations offer several advantages over longer, more traditional rotations. They enhance the natural productivity of better sites and of tree species with rapid juvenile growth. Returns on investment are realized in a shorter period and the risk of loss is reduced compared with long term investments. Production of wood and fiber can be maximized by...
Diamagnetism of rotating plasma
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.
Rotatable shear plate interferometer
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.
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).
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)
Modeling rapidly rotating stars
NASA Astrophysics Data System (ADS)
Rieutord, M.
2006-06-01
We review the quest of modeling rapidly rotating stars during the past 40 years and detail the challenges to be taken up by models facing new data from interferometry, seismology, spectroscopy... We then present the progress of the ESTER project aimed at giving a physically self-consistent model for the structure and evolution of rapidly rotating stars.
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
CENTRAL ROTATIONS OF MILKY WAY GLOBULAR CLUSTERS
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.
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.
Metacarpal rotational osteotomy.
Gross, M S; Gelberman, R H
1985-01-01
Maximum metacarpal rotation and corresponding phalangeal correction were measured in 80 fingers of 40 cadaver hands. Total metacarpal rotation averaged 50 degrees to 52 degrees in the index, long, and ring fingers and 69 degrees in the small finger. Phalangeal correction averaged 36 degrees to 37 degrees in the index, long, and ring fingers and 50 degrees in the small finger (70% of rotation in the metacarpal). The orientation of the metacarpophalangeal joint was not a significant limiting factor. However, the deep transverse metacarpal ligament did limit maximum rotation at the metacarpal and the phalanx. The advantages of basal metacarpal osteotomy make this technique the procedure of choice for correcting malrotation of up to an average of 18 degrees to 19 degrees for the index, long, and ring fingers. For the small finger, 20 degrees to 30 degrees of correction is possible, depending on the direction of rotation. A table has been devised to predict the correction for individual digits.
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.
Angular velocity distribution of a granular planar rotator in a thermalized bath.
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.
Quasi-stationary states in the Southern Hemisphere
NASA Technical Reports Server (NTRS)
Mo, K. C.
1986-01-01
Pattern correlations between daily anomalies have been used to study the persistence of the Southern Hemisphere circulations. The dataset consists of daily Australian analyses of 500 mb heights and sea level pressure for the period from 1972 to 1983. Compared to the Northern Hemisphere, the pattern correlations are much lower and more variable in the Southern Hemisphere. The mean one-day lag autocorrelation is only 0.57, compared to 0.81 in the Northern Hemisphere. The correlations increase significantly for the filtered anomalies, which consist of the planetary wavenumbers from 0 to 4. Subjective criteria based on the pattern correlations are used to select quasi-stationary events. A series of 5 or more daily maps is defined to be quasi-stationary if the pattern correlations between all pairs of five consecutive maps in this time series are larger than or equal to 0.5. In winter, quasi-stationary events can be classified in terms of wavenumbers. Waves 3 and 4 are by far the dominant waves. More than half of the events have large wave 3 amplitude with geographically fixed orientations.
A γ-ray Quasi-periodic Modulation in the Blazar PKS 0301-243?
NASA Astrophysics Data System (ADS)
Zhang, Peng-Fei; Yan, Da-Hai; Zhou, Jia-Neng; Fan, Yi-Zhong; Wang, Jian-Cheng; Zhang, Li
2017-08-01
We report a nominally high-confidence γ-ray quasi-periodic modulation in the blazar PKS 0301-243. For this target, we analyze its Fermi-LAT Pass 8 data from 2008 August to 2017 May. Two techniques, i.e., maximum likelihood optimization and exposure-weighted aperture photometry, are used to build the γ-ray light curves. Then, both the Lomb-Scargle periodogram and the weighted wavelet Z-transform are applied to the light curves to search for period signals. A quasi-periodicity with a period of 2.1 ± 0.3 yr appears at the significance level of ˜ 5σ , although it should be noted that this putative quasi-period variability is seen in a data set that is barely four times longer. We speculate that this γ-ray quasi-periodic modulation may be evidence of a binary supermassive black hole.
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.
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.
Hydrodynamic MagnetoRotational Instability Analog Experiment
NASA Astrophysics Data System (ADS)
Stemmley, Steven; Blackman, Eric; Caspary, Kyle; Gilson, Erik; Hung, Derek; Ji, Hantao; Sloboda, Peter
2016-10-01
The MagnetoRotational Instability (MRI) is thought to be responsible for angular momentum transport in accretion disks. This transport occurs when two magnetically coupled fluid elements are perturbed and radially stretch the sufficiently weak magnetic field. To mimic these astrophysical systems, a modified Taylor-Couette device was operated with water as the working fluid at varying rotation speeds to produce hydrodynamic quasi-Keplerian flows and with a pair of test masses coupled by a spring rather than a magnetic field. This scaled experiment simulates the spring-like forces between fluid elements brought on by magnetic tension. In attempts to visually observe this MRI analog, neutrally buoyant masses of varying size were coupled by means of a spring to a fixed point rotating with the fluid. Laser Doppler Velocimetry showed good agreement with ideal Taylor-Couette velocity profiles and that no significant perturbations were present when the masses were moving at the speed of the flow. Further investigations include varying the masses, springs, and shear profiles to obtain a map of the instability threshold boundary as well as determining the effect of the mass's geometry on the flow. Results from video recording measurements and analyses are presented and discussed.
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.
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.
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.
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
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.
Rotatable seal assembly. [Patent application; rotating targets
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.
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
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.
Supersonic quasi-axisymmetric vortex breakdown
NASA Technical Reports Server (NTRS)
Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.
1991-01-01
An extensive computational study of supersonic quasi-axisymmetric vortex breakdown in a configured circular duct is presented. The unsteady, compressible, full Navier-Stokes (NS) equations are used. The NS equations are solved for the quasi-axisymmetric flows using an implicit, upwind, flux difference splitting, finite volume scheme. The quasi-axisymmetric solutions are time accurate and are obtained by forcing the components of the flowfield vector to be equal on two axial planes, which are in close proximity of each other. The effect of Reynolds number, for laminar flows, on the evolution and persistence of vortex breakdown, is studied. Finally, the effect of swirl ration at the duct inlet is investigated.
Isokinetic shoulder rotator muscles in wheelchair athletes.
Bernard, P L; Codine, P; Minier, J
2004-04-01
To assess the influence of wheelchair propulsion and neurological level on isokinetic shoulder rotational strength. University of Montpellier, France Data were evaluated in three groups of subjects as follows: 12 nonathletes, 15 tennis players and 21 wheelchair athletes. We then compared 12 high paraplegic athletes (HPA) and nine low paraplegic athletes (LPA) within the group of 21 wheelchair athletes: The isokinetic tests were performed in the seated 45 degrees abducted test position in the scapular plane at 60, 180 and 300 degrees s(-1) for both shoulders. Peak torque and mean power values were gathered and, from these values, the internal/external rotation ratios were calculated. Intergroup comparison showed an influence of lesion and sport on peak torque at 180 and 300 degrees s(-1) for the internal rotators and significantly higher values of the internal/external ratios in the wheelchair athlete group. For mean power, we observed significant differences under all test conditions and significant differences for ratio only on the dominant side at 180 degrees s(-1) and on the dominant side at 300 degrees s(-1). Comparison of the two groups of paraplegic athletes showed significantly higher values of peak torque and mean power of the external rotators in the LPA for all test conditions. Neurological level of lesion does not systematically influence the development of internal rotator muscles; in contrast, the participation of the external rotators appears strongly correlated to neurological level. The comparison of the two sides in the two paraplegic groups showed that in two-thirds of the cases the values of the external rotators were significantly higher than those of the internal rotators on the nondominant side for peak torque and mean power. Ratios on the dominant side were systematically higher than on the nondominant side, with significant differences also noted in two-thirds of the cases. These results raise questions about the influence of neurological
Some remarks on quasi-Hermitian operators
Antoine, Jean-Pierre; Trapani, Camillo
2014-01-15
A quasi-Hermitian operator is an operator that is similar to its adjoint in some sense, via a metric operator, i.e., a strictly positive self-adjoint operator. Whereas those metric operators are in general assumed to be bounded, we analyze the structure generated by unbounded metric operators in a Hilbert space. Following our previous work, we introduce several generalizations of the notion of similarity between operators. Then we explore systematically the various types of quasi-Hermitian operators, bounded or not. Finally, we discuss their application in the so-called pseudo-Hermitian quantum mechanics.
Collisions between quasi-parallel shocks
NASA Technical Reports Server (NTRS)
Cargill, Peter J.
1991-01-01
The collision between pairs of quasi-parallel shocks is examined using hybrid numerical simulations. In the interaction, the two shocks are transmitted through each other leaving behind a hot plasma with a population of particles with energies in excess of 40 E0, where E0 is the kinetic energy of particles in the shock frame prior to the collision. The energization is more efficient for quasi-parallel shocks than parallel shocks. Collisions between shocks of equal strengths are more efficient than those that are unequal. The results are of importance for phenomena during the impulsive phase of solar flares, in the distant solar wind and at planetary bow shocks.
Spontaneous symmetry breaking in quasi one dimension
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.
What does physical rotation reveal about mental rotation?
Gardony, Aaron L; Taylor, Holly A; Brunyé, Tad T
2014-02-01
In a classic psychological science experiment, Shepard and Metzler (1971) discovered that the time participants took to judge whether two rotated abstract block figures were identical increased monotonically with the figures' relative angular disparity. They posited that participants rotate mental images to achieve a match and that mental rotation recruits motor processes. This interpretation has become central in the literature, but until now, surprisingly few researchers have compared mental and physical rotation. We had participants rotate virtual Shepard and Metzler figures mentally and physically; response time, accuracy, and real-time rotation data were collected. Results suggest that mental and physical rotation processes overlap and also reveal novel conclusions about physical rotation that have implications for mental rotation. Notably, participants did not rotate figures to achieve a match, but rather until they reached an off-axis canonical difference, and rotational strategies markedly differed for judgments of whether the figures were the same or different.
Asymptotically reduced equations for rapidly rotating and stably stratified flow
NASA Astrophysics Data System (ADS)
Nieves, David; Julien, Keith
2015-11-01
Observations by van Haren & Millot (2005) of the deep Western Mediterranean Sea and by Timmermans et al. (2006) of the deep Canadian Basin find vertical fluid motions to be as significant as horizontal motions for ocean dynamics. Since the classical quasi-geostrophic equations do not allow for such vertical motions reduced equations for geostrophically balanced flow with O(1) vertical motions are presented alongside their numerical solutions and results. The reduced equations describe flow constrained by rapid rotation and stable stratification and, in fact, are the stably stratified counterpart to the reduced equations used by Julien et al. in successful studies of rapidly rotating Rayleigh-Bénard convection. Specifically, the equations are valid in the small Rossby number (Ro 1) and O(1) Froude number limit. The focus here is a comparison to similar studies of rotating and stratified flow by Smith & Waleffe (2002), Wingate et al. (2011), and Marino et al. (2013) among others.
Hybrid simulations of rotational discontinuities. [Alfven wave propagation in astrophysics
NASA Technical Reports Server (NTRS)
Goodrich, C. C.; Cargill, P. J.
1991-01-01
1D hybrid simulations of rotational discontinuities (RDs) are presented. When the angle between the discontinuity normal and the magnetic field (theta-BN) is 30 deg, the RD broadens into a quasi-steady state of width 60-80 c/omega-i. The hodogram has a characteristic S-shape. When theta-BN = 60 deg, the RD is much narrower (10 c/omega-i). For right handed rotations, the results are similar to theta-BN = 30 deg. For left handed rotations, the RD does not evolve much from its initial conditions and the S-shape in the hodogram is much less visible. The results can be understood in terms of matching a fast mode wavelike structure upstream of the RD with an intermediate mode one downstream.
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.
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 ...
... 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 ...
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.
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)
NASA Technical Reports Server (NTRS)
Goody, R. M.
1982-01-01
The determination of the rotation rate of Uranus based on available observational evidence is discussed. Previous determinations of the rotation rate since the work of Lowell and Slipher (1912), which tended to converge on a period of 10.8 days until the mid 1970s, most likely due to mutual reinforcement between unreliable results, are reviewed. Recent independent determinations based on (1) the use of theoretical interior models together with observations of oblateness and the gravitational moment J2; (2) periodic brightness fluctuations; and (3) spectrographic measurements of Doppler shifts are then presented which yield a weighted mean value of 16.31 + or - 0.27 h for the rotational period of Uranus. It is noted that the detection of the motion of surface features across the disk by future high-resolution imaging and Voyager 2 observations may allow a direct determination of the rotational period of Uranus.
Rotator cuff repair - slideshow
... 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: ...
Energy loss of a heavy particle near 3D charged rotating hairy black hole
NASA Astrophysics Data System (ADS)
Naji, Jalil
2014-01-01
In this paper we consider a charged rotating black hole in three dimensions with a scalar charge and discuss the energy loss of a heavy particle moving near the black-hole horizon. We also study quasi-normal modes and find the dispersion relations. We find that the effect of scalar charge and electric charge increases the energy loss.
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.
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.
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.
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.
NASA Technical Reports Server (NTRS)
Wilcox, Brian H.; Tso, Kam S.; Litwin, Todd E.; Hayati, Samad A.; Bon, Bruce B.
1991-01-01
Experimental robotic system semiautomatically grasps rotating object, stops rotation, and pulls object to rest in fixture. Based on combination of advanced techniques for sensing and control, constructed to test concepts for robotic recapture of spinning artificial satellites. Potential terrestrial applications for technology developed with help of system includes tracking and grasping of industrial parts on conveyor belts, tracking of vehicles and animals, and soft grasping of moving objects in general.
Electromagnetic rotational actuation.
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.
Lewis, J S
2009-04-01
A review was conducted to synthesise the available research literature on the pathogenesis of rotator cuff tendinopathy. Musculoskeletal disorders of the shoulder are extremely common, with reports of prevalence ranging from one in three people experiencing shoulder pain at some stage of their lives to approximately half the population experiencing at least one episode of shoulder pain annually. Pathology of the soft tissues of the shoulder, including the musculotendinous rotator cuff and subacromial bursa, is a principal cause of pain and suffering. The pathoaetiology of rotator cuff failure is multifactorial and results from a combination of intrinsic, extrinsic and environmental factors. The specialised morphology of the rotator cuff, together with the effects of stress shielding, may contribute to the development of rotator cuff tendinopathy. Profound changes within the subacromial bursa are strongly related to the pathology and resulting symptoms. A considerable body of research is necessary to more fully understand the aetiology and pathohistology of rotator cuff tendinopathy and its relationship with bursal pathology. Once this knowledge exists more effective management will become available.
X-31 Quasi-Tailless (Artist Concept)
NASA Technical Reports Server (NTRS)
1993-01-01
This is a computer enhanced artist's concept of a semi-tailless X-31 Enhanced Fighter Maneuverability Aircraft in flight. In 1994, software was installed in the X-31 to demonstrate the feasibility of stabilizing a tailless aircraft at supersonic speed, using thrust vectoring. This software allowed destabilization through the control laws of the aircraft in incremental steps to the goal of simulation 100 percent tail-off. Quasi-tailless tests began in 1994. The first phase started with supersonic evaluations at Mach 1.2. Later subsonic evaluations were performed. During the flights the aircraft was destabilized with the rudder to stability levels that would be encountered if the aircraft had a reduced-size vertical tail. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the
X-31 Quasi-Tailless (Artist Concept)
NASA Technical Reports Server (NTRS)
1994-01-01
This is a computer enhanced artist's concept of a semi-tailless X-31 Enhanced Fighter Maneuverability Aircraft in flight. In 1994, software was installed in the X-31 to demonstrate the feasibility of stabilizing a tailless aircraft at supersonic speed, using thrust vectoring. This software allowed destabilization through the control laws of the aircraft in incremental steps to the goal of simulation 100 percent tail-off. Quasi-tailless tests began in 1994. The first phase started with supersonic evaluations at Mach 1.2. Later subsonic evaluations were performed. During the flights the aircraft was destabilized with the rudder to stability levels that would be encountered if the aircraft had a reduced size vertical tail. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the
The global long-range order of quasi-periodic patterns in Islamic architecture.
Al Ajlouni, Rima A
2012-03-01
Three decades after their discovery, the unique long-range structure of quasicrystals still poses a perplexing puzzle. The fact that some ancient Islamic patterns share similar quasi-periodic symmetries has prompted several scientists to investigate their underlying geometry and construction methods. However, available structural models depend heavily on local rules and hence they were unable to explain the global long-range order of Islamic quasi-periodic patterns. This paper shows that ancient designers, using simple consecutive geometry, have resolved the complicated long-range principles of quasi-periodic formations. Derived from these principles, a global multi-level structural model is presented that is able to describe the global long-range translational and orientational order of quasi-periodic formations. The proposed model suggests that the position of building units, locally and globally, is defined by one framework, and not tiled based on local rules (matching, overlapping or subdividing). In this way, quasi-periodic formations can grow rapidly ad infinitum without the need for any defects or mismatches. The proposed model, which presents a novel approach to the study of quasi-periodic symmetries, will hopefully provide a deeper understanding of the structure of quasicrystals at an atomic scale, allowing scientists to achieve improved control over their composition and structure.
On quasi-periodic variations of low-energy cosmic rays observed near earth.
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. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR
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.
Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR.
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.
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.
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.
Electroglottographic Quasi-open quotient and amplitude in crescendo phonation.
Hacki, T
1996-12-01
Crescendo phonation (swelltone) was used to evaluate the laryngeal tensioning behavior of seven normal speakers and of 12 dysphonic patients. EGG quasi-open quotient (qOq), stroboscopic open quotient, and vocal sound pressure level (SPL) were measured, and EGG amplitude and the mucosal wave were assessed qualitatively. For normal speakers, the qOq decreased greatly as vocal intensity increased. The same tendency was observed, but to a lesser extent, among hyperfunctional dysphonics. In contrast, qOq increased with vocal intensity among the hypofunctional dysphonics. The crescendo task combined with EGG assessment appears to offer a valid approach to the classification of laryngeal dysfunctions.
Rotating waves within a hollow vortex core
NASA Astrophysics Data System (ADS)
Abderrahmane, Hamid Ait; Siddiqui, Kamran; Vatistas, Georgios H.
2011-03-01
The rotating waves within a hollow vortex core (polygonal patterns) are generated under shallow water conditions inside a cylindrical tank by a revolving disk at its bottom. We previously reported some basic features of these polygonal patterns during transition and at the equilibrium states. The present paper includes a more comprehensive investigation into the transition process of these polygonal patterns and expands the recent partial results that have been previously reported. We show that the parent wave (or the N- gon pattern) to disk frequencies ratio is around one-third (1/3) regardless of the flow conditions . A detailed insight into the transition process from the parent wave N- gon to daughter wave ( N + 1)- gon is provided, which consists of two regimes, quasi-periodic and synchronized. Based on these observations, we explained the shrinking of the disk speed subintervals over which the N- gon patterns occur, when N increases.
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.
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)
Ego-rotation and object-rotation in major depressive disorder.
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.
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.
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
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.,
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.
Rotating superconductor magnet for producing rotating lobed magnetic field lines
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.
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.
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.
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.
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.
Experimental studies of quasi-fission reactions
Back, B.B.
1988-01-01
A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are distinct from compound fission reactions by bypassing the stage of a completely fused-system. This typically means that they are associated with short reaction times, which results in several measurable characteristics such as broken forward-backward symmetries, large anisotropies of the angular distributions and increased widths of the fragment mass distributions. The distinction between quasi-fission and deep inelastic reactions is less stringent and has the character of a gradual evolution from one reaction type to the other, as found also as quasi-elastic reaction evolves into deeply inelastic processes as a function of the total kinetic energy loss. In the present paper some of the experimental data characterizing quasi-fission reactions are reviewed and discussed. 22 refs., 6 figs.
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…
Representable states on quasilocal quasi *-algebras
Bagarello, F.; Trapani, C.; Triolo, S.
2011-01-15
Continuing a previous analysis originally motivated by physics, we consider representable states on quasilocal quasi *-algebras, starting with examining the possibility for a compatible family of local states to give rise to a global state. Some properties of local modifications of representable states and some aspects of their asymptotic behavior are also considered.
Implementing a Critically Quasi-Ethnographic Approach
ERIC Educational Resources Information Center
Murtagh, Lisa
2007-01-01
This paper provides an account of the methodological approach of a study designed to address some fundamental questions relating to formative assessment. The paper reports on the use of a critically quasi-ethnographic approach and describes the practicalities of adopting such an approach. The validity of the study is also considered, reflecting on…
Quasi-equilibria in reduced Liouville spaces.
Halse, Meghan E; Dumez, Jean-Nicolas; Emsley, Lyndon
2012-06-14
The quasi-equilibrium behaviour of isolated nuclear spin systems in full and reduced Liouville spaces is discussed. We focus in particular on the reduced Liouville spaces used in the low-order correlations in Liouville space (LCL) simulation method, a restricted-spin-space approach to efficiently modelling the dynamics of large networks of strongly coupled spins. General numerical methods for the calculation of quasi-equilibrium expectation values of observables in Liouville space are presented. In particular, we treat the cases of a time-independent Hamiltonian, a time-periodic Hamiltonian (with and without stroboscopic sampling) and powder averaging. These quasi-equilibrium calculation methods are applied to the example case of spin diffusion in solid-state nuclear magnetic resonance. We show that there are marked differences between the quasi-equilibrium behaviour of spin systems in the full and reduced spaces. These differences are particularly interesting in the time-periodic-Hamiltonian case, where simulations carried out in the reduced space demonstrate ergodic behaviour even for small spins systems (as few as five homonuclei). The implications of this ergodic property on the success of the LCL method in modelling the dynamics of spin diffusion in magic-angle spinning experiments of powders is discussed.
Graphical Models for Quasi-Experimental Designs
ERIC Educational Resources Information Center
Steiner, Peter M.; Kim, Yongnam; Hall, Courtney E.; Su, Dan
2017-01-01
Randomized controlled trials (RCTs) and quasi-experimental designs like regression discontinuity (RD) designs, instrumental variable (IV) designs, and matching and propensity score (PS) designs are frequently used for inferring causal effects. It is well known that the features of these designs facilitate the identification of a causal estimand…
Quasi-likelihood for Spatial Point Processes
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
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.
Vortex Stability In Two -layer Rotating Shallow-water Flows
NASA Astrophysics Data System (ADS)
Carton, Xavier; Baey, Jean-Michel
The stability of circular vortices subject to an initial normal-mode perturbation is studied in a two-layer shallow-water fluid with rigid lid, flat bottom and constant background rotation. Considerable similarity with quasi-geostrophic dynamics is found for linear (barotropic or baroclinic) instability, except in the frontal and nonlinear barotropic limits. This discrepancy is explained by asymptotic models. In many cases, the elliptical mode of deformation is the most unstable one. The ability of these perturbed circular vortices to stabilize nonlinearly as long-lived multipoles is then investigated. For elliptical perturbations, steady tripoles form from moderately unstable vortices as in the quasi-geostrophic limit. These tripoles, which exhibit various 3D structures, are robust when perturbed by non coherent disturbances. More unstable circular vortices break as two dipoles, propagating in opposite directions. Triangular perturbations can also lead to stationary quadrupoles or to dipolar breaking. The similarity with quasi-geostrophic dynamics, which ext ends to these nonlinear regimes, is related to the weakness of the divergent circulation, as shown by the analysis of the Lighthill equation. J.M. Baey &X. Carton, 2001: "Piecewise-constant vortices in a two-layer shallow - water flow". Advances in mathematical modelling of atmosphere and ocean dynamics, Kluwer Acad. Publ., 61, p.87-92. J.M. Baey &X. Carton, 2002: "Vortex multipoles in two-layer rotating shallow -water flows". To appear in J. Fluid Mech.
NASA Technical Reports Server (NTRS)
Kelkar, A. D.
1984-01-01
In thin composite laminates, the first level of visible damage occurs in the back face and is called back face spalling. A plate-membrane coupling model, and a finite element model to analyze the large deformation behavior of eight-ply quasi-isotropic circular composite plates under impact type point loads are developed. The back face spalling phenomenon in thin composite plates is explained by using the plate-membrane coupling model and the finite element model in conjunction with the fracture mechanics principles. The experimental results verifying these models are presented. Several conclusions concerning the deformation behavior are reached and discussed in detail.
Influence of gravity waves on the internal rotation and Li abundance of solar-type stars.
Charbonnel, Corinne; Talon, Suzanne
2005-09-30
The Sun's rotation profile and lithium content have been difficult to understand in the context of conventional models of stellar evolution. Classical hydrodynamic models predict that the solar interior must rotate highly differentially, in disagreement with observations. It has recently been shown that internal waves produced by convection in solar-type stars produce an asymmetric, shear layer oscillation, similar to Earth's quasi-biennial oscillation, that leads to efficient angular momentum redistribution from the core to the envelope. We present results of a model that successfully reproduces both the rotation profile and the surface abundance of lithium in solar-type stars of various ages.
Using custom potentials to access quantum Hall states in rotating Bose gases
NASA Astrophysics Data System (ADS)
Morris, Alexis G.; Feder, David L.
2007-03-01
The exact ground states of zero-temperature rotating Bose gases confined in quasi-two-dimensional harmonic traps are studied numerically, for small numbers of alkali atoms. As the rotation frequency increases, the interacting Bose gas undergoes a series of transitions from one quantum Hall state to another. We have investigated the possibility of facilitating access to specific quantum Hall states through the addition of customized potentials to the existing trapping potential. For the right choice of potential, we show that creation of predetermined quantum Hall states in rotating Bose gases should be possible using current experimental setups. (Research supported by NSERC, iCORE and CFI)
Single point modeling of rotating turbulent flows
NASA Technical Reports Server (NTRS)
Hadid, A. H.; Mansour, N. N.; Zeman, O.
1994-01-01
A model for the effects of rotation on turbulence is proposed and tested. These effects which influence mainly the rate of turbulence decay are modeled in a modified turbulent energy dissipation rate equation that has explicit dependence on the mean rotation rate. An appropriate definition of the rotation rate derived from critical point theory and based on the invariants of the deformation tensor is proposed. The modeled dissipation rate equation is numerically well behaved and can be used in conjunction with any level of turbulence closure. The model is applied to the two-equation kappa-epsilon turbulence model and is used to compute separated flows in a backward-facing step and an axisymmetric swirling coaxial jets into a sudden expansion. In general, the rotation modified dissipation rate model shows some improvements over the standard kappa-epsilon model.
Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography
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
Chen-Nester-Tung quasi-local energy and Wang-Yau quasi-local mass
NASA Astrophysics Data System (ADS)
Liu, Jian-Liang; Yu, Chengjie
2017-10-01
In this paper, we show that the Chen-Nester-Tung (CNT) quasi-local energy with 4D isometric matching references is closely related to the Wang-Yau (WY) quasi-local energy. As a particular example, we compute the second variation of the CNT quasi-local energy for axially symmetric Kerr-like spacetimes with axially symmetric embeddings at the obvious critical point (0 , 0) and find that it is a saddle critical point in most of the cases. Also, as a byproduct, we generalize a previous result about the coincidence of the CNT quasi-local energy and Brown-York mass for axially symmetric Kerr-like spacetimes by Tam and the first author Liu and Tam (2016) to general spacetimes.
Photofabrication of two-dimensional quasi-crystal patterns on UV-curable molecular azo glass films.
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.
General Surgery Resident Satisfaction on Cardiothoracic Rotations.
Lussiez, Alisha; Bevins, Jack; Plaska, Andrew; Rosin, Vadim; Reddy, Rishindra M
2016-01-01
General surgery residents' exposure to cardiothoracic (CT) surgery rotations has decreased, which may affect resident satisfaction. We surveyed general surgery graduates to assess the relationships among rotation satisfaction, CT disease exposure, rotation length, mentorship, and mistreatment. A survey assessing CT curriculum, exposure, mentorship, and satisfaction was forwarded to general surgery graduates from 17 residency programs. A Wilcoxon rank-sum test was used to assess statistical significance of ordinal level data. Statistical significance was defined as p < 0.05. This study was conducted at the University of Michigan Health System in Ann Arbor, MI, a tertiary care center. The survey was sent to approximately 1300 graduates of general surgery residency programs who graduated between the years of 1999 to 2014. A total of 94 responses were completed and received. Receiving adequate exposure to CT procedures and disease management was significantly associated with higher satisfaction ratings for all procedures, particularly thoracotomy incisions (p < 0.001), empyemas and pleural effusions (p < 0.001), and lung cancer care (p < 0.001). The absence of mistreatment and good/very good mentorship were both positively associated with higher reported satisfaction (p = 0.018 and p < 0.001, respectively). Increased length of time on CT rotation was neither associated with improved levels of satisfaction nor with an improvement in the quality of mentorship. Rotation satisfaction is positively associated with procedure exposure, better mentorship, and the absence of mistreatment. Longer rotation length was not associated with satisfaction. Shorter rotations are not detrimental to training if they have focused clinical exposure and invested mentors to maximize resident satisfaction. These specific markers of rotation quality are useful in curricular design. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.
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.
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.
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.
STRUCTURE OF UNIFORMLY ROTATING STARS
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.
Rotator cuff muscles perform different functional roles during shoulder external rotation exercises.
Tardo, Daniel T; Halaki, Mark; Cathers, Ian; Ginn, Karen A
2013-03-01
The aim of this study was to compare activity in shoulder muscles during an external rotation task under conditions of increasing arm support to investigate whether changing support requirements would influence muscle recruitment levels, particularly in the rotator cuff (RC) muscles. Electromyographic recordings were collected from seven shoulder muscles using surface and indwelling electrodes. The dominant shoulder of 14 healthy participants were examined during dynamic shoulder external rotation performed at 90° abduction with the arm fully supported, partially supported, and unsupported. Linear regressions between arm support load and the averaged muscle activity across participants for each muscle showed infraspinatus predominantly contributing to rotating the shoulder whilst supraspinatus, deltoid, upper trapezius, and serratus anterior were predominantly functioning in support/stabilization roles. During dynamic shoulder external rotation in mid-range abduction, the RC muscles perform different functional roles. Infraspinatus is responsible for producing external rotation torque, supraspinatus is playing a larger joint stabilizer role, and subscapularis is contributing minimally to joint stability. The results also indicate that increasing support load requirements during an external rotation task may be a functionally specific way to retrain the stabilization function of axioscapular muscles. Manipulating joint stabilization requirements while maintaining constant rotational load is a novel method of investigating the differential contribution of muscles to joint movement and stabilization during a given task. Copyright © 2012 Wiley Periodicals, Inc.
Rotational spectra of o-, m-, and p-cyanophenol and internal rotation of p-cyanophenol.
Conrad, Andrew R; Barefoot, Nathan Z; Tubergen, Michael J
2010-08-01
Rotational spectra of p-, m-, and o-cyanophenol have been measured in the range of 10.5-21 GHz and fit using Watson's A-reduction Hamiltonian coupled with nuclear quadrupole coupling interaction terms for the (14)N nuclei. Ab initio calculations at the MP2/6-311++G(d,p) and CCSD(T)/6-311++G(d,p) levels predict the cis conformers of m- and o-cyanophenol to be more stable than the corresponding trans conformers. A natural bond orbital analysis of the hydrogen bonding interaction in o- and m-cyanophenol revealed an intramolecular hydrogen bond that preferentially stabilizes the cis conformer of o-cyanophenol but there was no evidence of hydrogen bonding interactions in cis m-cyanophenol. We recorded 25 a- and b-type rotational transitions for cis o-cyanophenol; the rotational constants are A = 3053.758(2) MHz, B = 1511.2760(3) MHz, and C = 1010.7989(2) MHz. The trans conformer of o-cyanophenol was not observed. We recorded 14 a- and b-type rotational transitions for cis m-cyanophenol and 16 a- and b-type rotational transitions for trans m-cyanophenol. The rotational constants are A = 3408.9200(2) MHz, B = 1205.8269(2) MHz, and C = 890.6672(1) MHz and A = 3403.1196(3) MHz, B = 1208.4903(2) MHz, and C = 891.7241(2) MHz for the cis and trans species, respectively. Rotational transitions of the p-cyanophenol monomer are split due to the internal rotation of the hydroxyl group with respect to the aromatic ring. We recorded 25 a- and b-type rotational transitions for p-cyanophenol; the b-type transitions are split by 40 MHz. The rotational constants are A = 5612.96(2) MHz, B = 990.4283(6) MHz, and C = 841.9363(6) MHz. The ground state spitting DeltaE is 20.1608(6) MHz and the barrier to internal rotation, V(2), is 1413(2) cm(-1) from a fit of the rotational transitions to an internal axis system Hamiltonian. The barrier to internal rotation was modeled at the MP2/6-311++G(d,p) level and the effects of substituents on the phenolic ring and the barriers to internal rotation
Electrotherapy modalities for rotator cuff disease.
Page, Matthew J; Green, Sally; Mrocki, Marshall A; Surace, Stephen J; Deitch, Jessica; McBain, Brodwen; Lyttle, Nicolette; Buchbinder, Rachelle
2016-06-10
Management of rotator cuff disease may include use of electrotherapy modalities (also known as electrophysical agents), which aim to reduce pain and improve function via an increase in energy (electrical, sound, light, or thermal) into the body. Examples include therapeutic ultrasound, low-level laser therapy (LLLT), transcutaneous electrical nerve stimulation (TENS), and pulsed electromagnetic field therapy (PEMF). These modalities are usually delivered as components of a physical therapy intervention. This review is one of a series of reviews that form an update of the Cochrane review, 'Physiotherapy interventions for shoulder pain'. To synthesise available evidence regarding the benefits and harms of electrotherapy modalities for the treatment of people with rotator cuff disease. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3), Ovid MEDLINE (January 1966 to March 2015), Ovid EMBASE (January 1980 to March 2015), CINAHL Plus (EBSCOhost, January 1937 to March 2015), ClinicalTrials.gov and the WHO ICTRP clinical trials registries up to March 2015, unrestricted by language, and reviewed the reference lists of review articles and retrieved trials, to identify potentially relevant trials. We included randomised controlled trials (RCTs) and quasi-randomised trials, including adults with rotator cuff disease (e.g. subacromial impingement syndrome, rotator cuff tendinitis, calcific tendinitis), and comparing any electrotherapy modality with placebo, no intervention, a different electrotherapy modality or any other intervention (e.g. glucocorticoid injection). Trials investigating whether electrotherapy modalities were more effective than placebo or no treatment, or were an effective addition to another physical therapy intervention (e.g. manual therapy or exercise) were the main comparisons of interest. Main outcomes of interest were overall pain, function, pain on motion, patient-reported global assessment of treatment success
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.
Random quasi-phase-matched conversion of broadband radiation in a nonlinear photonic crystal
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.
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.
Biomechanics of the incudo-malleolar-joint - Experimental investigations for quasi-static loads.
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.
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).
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.
NASA Astrophysics Data System (ADS)
Dorbolo, Stephane; Adami, Nicolas; Grasp Team
2014-11-01
The motion of ice discs released at the surface of a thermalized bath was investigated. As observed in some rare events in the Nature, the discs start spinning spontaneously. The motor of this motion is the cooling of the water close to the ice disc. As the density of water is maximum at 4°C, a downwards flow is generated from the surface of the ice block to the bottom. This flow generates the rotation of the disc. The speed of rotation depends on the mass of the ice disc and on the temperature of the bath. A model has been constructed to study the influence of the temperature of the bath. Finally, ice discs were put on a metallic plate. Again, a spontaneous rotation was observed. FNRS is thanked for financial support.
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.
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.
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.
Lattice QCD in rotating frames.
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.
NASA Astrophysics Data System (ADS)
Kissin, Yevgeni; Thompson, Christopher
2015-07-01
The internal rotation of post-main sequence stars is investigated, in response to the convective pumping of angular momentum toward the stellar core, combined with a tight magnetic coupling between core and envelope. The spin evolution is calculated using model stars of initial mass 1, 1.5, and 5 {M}⊙ , taking into account mass loss on the giant branches. We also include the deposition of orbital angular momentum from a sub-stellar companion, as influenced by tidal drag along with the excitation of orbital eccentricity by a fluctuating gravitational quadrupole moment. A range of angular velocity profiles {{Ω }}(r) is considered in the envelope, extending from solid rotation to constant specific angular momentum. We focus on the backreaction of the Coriolis force, and the threshold for dynamo action in the inner envelope. Quantitative agreement with measurements of core rotation in subgiants and post-He core flash stars by Kepler is obtained with a two-layer angular velocity profile: uniform specific angular momentum where the Coriolis parameter {Co}\\equiv {{Ω }}{τ }{con}≲ 1 (here {τ }{con} is the convective time), and {{Ω }}(r)\\propto {r}-1 where {Co}≳ 1. The inner profile is interpreted in terms of a balance between the Coriolis force and angular pressure gradients driven by radially extended convective plumes. Inward angular momentum pumping reduces the surface rotation of subgiants, and the need for a rejuvenated magnetic wind torque. The co-evolution of internal magnetic fields and rotation is considered in Kissin & Thompson, along with the breaking of the rotational coupling between core and envelope due to heavy mass loss.
Non-Axisymmetric Shaping of Tokamaks Preserving Quasi-Axisymmetry
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.
Rotating bubble membrane radiator
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.
Rotating shielded crane system
Commander, John C.
1988-01-01
A rotating, radiation shielded crane system for use in a high radiation test cell, comprises a radiation shielding wall, a cylindrical ceiling made of radiation shielding material and a rotatable crane disposed above the ceiling. The ceiling rests on an annular ledge intergrally attached to the inner surface of the shielding wall. Removable plugs in the ceiling provide access for the crane from the top of the ceiling into the test cell. A seal is provided at the interface between the inner surface of the shielding wall and the ceiling.
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.
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.
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.
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.
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.
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.
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.
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.
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.
THE ROTATION PROFILE OF SOLAR MAGNETIC FIELDS BETWEEN {+-}60 Degree-Sign LATITUDES
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.
The domiciliary care market in Scotland: quasi-markets revisited.
Curtice, Lisa; Fraser, Fiona
2000-07-01
By offering people the choice of care at home, the policy of encouraging local authorities to purchase domiciliary care services from voluntary and private providers was intended to achieve a key part of the community care agenda. A study to establish the extent to which there was a mixed economy in the purchase and provision of domiciliary care in Scotland in 1996 revealed reluctance by local authority managers to divest the provision of domiciliary care to voluntary and private agencies. In a telephone survey of purchasers, some social work respondents noted a preference for voluntary over private providers and expressed concern as to whether either could take over the bulk of domiciliary care provision. These attitudes were reflected in the pattern of market development observed. Five hundred and ninety providers were identified, but a postal survey of a random sample of one in two providers (response rate 66%) found that the independent sector's share of the market, measured as the proportion of weekly care hours provided, was small compared with the position in England and Wales at that time (15 : 36%). It is concluded that understanding of the development of the quasi-market in domiciliary care in the UK must now take account of slower development in Scotland. Explanation for the difference may lie in the level of state regulation, for in Scotland there was no compulsion on local authorities to purchase from the independent sector. Paradoxically, the quasi-market in England developed through strong state regulation, whereas in Scotland the strength of policy networks may account for the persistence of a more traditional welfare state model. The paper questions whether the incentives for change were sufficient in Scotland under the quasi-market. If local partnerships do not deliver these results the government may have to take a more active role to modernise domiciliary care services.
Rotation Elastogram Estimation Using Synthetic Transmit Aperture Technique.
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
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).
Holographic studies of quasi-topological gravity
NASA Astrophysics Data System (ADS)
Myers, Robert C.; Paulos, Miguel F.; Sinha, Aninda
2010-08-01
Quasi-topological gravity is a new gravitational theory including curvaturecubed interactions and for which exact black hole solutions were constructed. In a holographic framework, classical quasi-topological gravity can be thought to be dual to the large N c limit of some non-supersymmetric but conformal gauge theory. We establish various elements of the AdS/CFT dictionary for this duality. This allows us to infer physical constraints on the couplings in the gravitational theory. Further we use holography to investigate hydrodynamic aspects of the dual gauge theory. In particular, we find that the minimum value of the shear-viscosity-to-entropy-density ratio for this model is η/ s ≃ 0.4140/(4π).
Quasi-Neutral Theory of Epidemic Outbreaks
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