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Sample records for sagittal angular rotation

  1. Measurement and Finite Element Model Validation of Immature Porcine Brain-Skull Displacement during Rapid Sagittal Head Rotations.

    Science.gov (United States)

    Pasquesi, Stephanie A; Margulies, Susan S

    2018-01-01

    Computational models are valuable tools for studying tissue-level mechanisms of traumatic brain injury, but to produce more accurate estimates of tissue deformation, these models must be validated against experimental data. In this study, we present in situ measurements of brain-skull displacement in the neonatal piglet head ( n  = 3) at the sagittal midline during six rapid non-impact rotations (two rotations per specimen) with peak angular velocities averaging 51.7 ± 1.4 rad/s. Marks on the sagittally cut brain and skull/rigid potting surfaces were tracked, and peak values of relative brain-skull displacement were extracted and found to be significantly less than values extracted from a previous axial plane model. In a finite element model of the sagittally transected neonatal porcine head, the brain-skull boundary condition was matched to the measured physical experiment data. Despite smaller sagittal plane displacements at the brain-skull boundary, the corresponding finite element boundary condition optimized for sagittal plane rotations is far less stiff than its axial counterpart, likely due to the prominent role of the boundary geometry in restricting interface movement. Finally, bridging veins were included in the finite element model. Varying the bridging vein mechanical behavior over a previously reported range had no influence on the brain-skull boundary displacements. This direction-specific sagittal plane boundary condition can be employed in finite element models of rapid sagittal head rotations.

  2. Measurement and Finite Element Model Validation of Immature Porcine Brain–Skull Displacement during Rapid Sagittal Head Rotations

    Science.gov (United States)

    Pasquesi, Stephanie A.; Margulies, Susan S.

    2018-01-01

    Computational models are valuable tools for studying tissue-level mechanisms of traumatic brain injury, but to produce more accurate estimates of tissue deformation, these models must be validated against experimental data. In this study, we present in situ measurements of brain–skull displacement in the neonatal piglet head (n = 3) at the sagittal midline during six rapid non-impact rotations (two rotations per specimen) with peak angular velocities averaging 51.7 ± 1.4 rad/s. Marks on the sagittally cut brain and skull/rigid potting surfaces were tracked, and peak values of relative brain–skull displacement were extracted and found to be significantly less than values extracted from a previous axial plane model. In a finite element model of the sagittally transected neonatal porcine head, the brain–skull boundary condition was matched to the measured physical experiment data. Despite smaller sagittal plane displacements at the brain–skull boundary, the corresponding finite element boundary condition optimized for sagittal plane rotations is far less stiff than its axial counterpart, likely due to the prominent role of the boundary geometry in restricting interface movement. Finally, bridging veins were included in the finite element model. Varying the bridging vein mechanical behavior over a previously reported range had no influence on the brain–skull boundary displacements. This direction-specific sagittal plane boundary condition can be employed in finite element models of rapid sagittal head rotations. PMID:29515995

  3. Angled oblique sagittal MR imaging of rotator cuff tears: comparison with standard oblique sagittal images

    International Nuclear Information System (INIS)

    Tuite, M.J.; Asinger, D.; Orwin, J.F.

    2001-01-01

    Objective. To compare the accuracy for diagnosing rotator cuff tears of oblique coronal images supplemented with standard oblique sagittal images versus thinner-section angled oblique sagittal images.Design and patients. The study included 75 consecutive patients who had a shoulder MR scan followed by arthroscopy. MR images included oblique coronal, oblique sagittal (4 mm thick, 1 mm interslice gap), and angled oblique sagittal (3 mm/0.2 mm) images perpendicular to the lateral cuff. A musculoskeletal staff radiologist and fellow separately evaluated the cuff for tears on the oblique coronal images supplemented with either the oblique sagittal or the angled sagittal images.Results. For distinguishing a cuff tear from no tear, the staff radiologist had an accuracy of 0.76 (95% confidence interval: 0.67, 0.85) with the standard sagittal set, and 0.88 (0.80, 0.95) with the angled set (P=0.04). There was a nonsignificant improvement in accuracy for the fellow, calculated as 0.73 (0.63, 0.83) on the standard sagittal set and 0.76 (0.67, 0.85) on the angled set. Both readers also improved their diagnostic accuracy for partial-thickness tears with the angled set, although the improvement was statistically significant only for the staff radiologist.Conclusion. There is a slight improvement in accuracy for diagnosing rotator cuff tears, particularly partial-thickness tears, for the more experienced radiologist using thinner-section angled oblique sagittal images. These images may be useful as a supplemental sequence in patients where it is important to identify partial-thickness tears accurately. (orig.)

  4. Angled oblique sagittal MR imaging of rotator cuff tears: comparison with standard oblique sagittal images

    Energy Technology Data Exchange (ETDEWEB)

    Tuite, M J; Asinger, D; Orwin, J F [Dept. of Radiology, Univ. of Wisconsin Hospital and Clinics, Madison, WI (United States)

    2001-05-01

    Objective. To compare the accuracy for diagnosing rotator cuff tears of oblique coronal images supplemented with standard oblique sagittal images versus thinner-section angled oblique sagittal images.Design and patients. The study included 75 consecutive patients who had a shoulder MR scan followed by arthroscopy. MR images included oblique coronal, oblique sagittal (4 mm thick, 1 mm interslice gap), and angled oblique sagittal (3 mm/0.2 mm) images perpendicular to the lateral cuff. A musculoskeletal staff radiologist and fellow separately evaluated the cuff for tears on the oblique coronal images supplemented with either the oblique sagittal or the angled sagittal images.Results. For distinguishing a cuff tear from no tear, the staff radiologist had an accuracy of 0.76 (95% confidence interval: 0.67, 0.85) with the standard sagittal set, and 0.88 (0.80, 0.95) with the angled set (P=0.04). There was a nonsignificant improvement in accuracy for the fellow, calculated as 0.73 (0.63, 0.83) on the standard sagittal set and 0.76 (0.67, 0.85) on the angled set. Both readers also improved their diagnostic accuracy for partial-thickness tears with the angled set, although the improvement was statistically significant only for the staff radiologist.Conclusion. There is a slight improvement in accuracy for diagnosing rotator cuff tears, particularly partial-thickness tears, for the more experienced radiologist using thinner-section angled oblique sagittal images. These images may be useful as a supplemental sequence in patients where it is important to identify partial-thickness tears accurately. (orig.)

  5. Rotations and angular momentum

    International Nuclear Information System (INIS)

    Nyborg, P.; Froyland, J.

    1979-01-01

    This paper is devoted to the analysis of rotational invariance and the properties of angular momentum in quantum mechanics. In particular, the problem of addition of angular momenta is treated in detail, and tables of Clebsch-Gordan coefficients are included

  6. Comparing the Effectiveness of Sagittal Balance, Foraminal Stenosis, and Preoperative Cord Rotation in Predicting Postoperative C5 Palsy.

    Science.gov (United States)

    Chugh, Arunit J S; Weinberg, Douglas S; Alonso, Fernando; Eubanks, Jason D

    2017-11-01

    Retrospective cohort review. To determine whether preoperative cord rotation is independently correlated with C5 palsy when analyzed alongside measures of sagittal balance and foraminal stenosis. Postoperative C5 palsy is a well-documented complication of cervical procedures with a prevalence of 4%-8%. Recent studies have shown a correlation with preoperative spinal cord rotation. There have been few studies, however, that have examined the role of sagittal balance and foraminal stenosis in the development of C5 palsy. A total of 77 patients who underwent cervical decompression-10 of whom developed C5 palsy-were reviewed. Sagittal balance was assessed using curvature angle and curvature index on radiographs and magnetic resonance image (MRI). Cord rotation was assessed on axial MRI. C4-C5 foraminal stenosis was assessed on sagittal MRI using area measurements and a grading scale. Demographics and information on surgical approach were gathered from chart review. Correlation with C5 palsy was performed by point-biserial, χ, and regression analyses. Point-biserial analysis indicated that only cord rotation showed significance (Pbalance did not correlate with presence of C5 palsy. Logistic regression model yielded cord rotation as the only significant independent predictor of C5 palsy. For every degree of axial cord rotation, the likelihood ratio for suffering a C5 palsy was 3.93 (95% confidence interval, 2.01-8.66; Ppoints to mechanisms other than direct compression as the etiology. In addition, the lack of correlation with postoperative changes in sagittal balance hints that measures of curvature angle and curvature index may not be appropriate to accurately predict this complication. Level 3.

  7. Rotating Hele-Shaw cell with a time-dependent angular velocity

    Science.gov (United States)

    Anjos, Pedro H. A.; Alvarez, Victor M. M.; Dias, Eduardo O.; Miranda, José A.

    2017-12-01

    Despite the large number of existing studies of viscous flows in rotating Hele-Shaw cells, most investigations analyze rotational motion with a constant angular velocity, under vanishing Reynolds number conditions in which inertial effects can be neglected. In this work, we examine the linear and weakly nonlinear dynamics of the interface between two immiscible fluids in a rotating Hele-Shaw cell, considering the action of a time-dependent angular velocity, and taking into account the contribution of inertia. By using a generalized Darcy's law, we derive a second-order mode-coupling equation which describes the time evolution of the interfacial perturbation amplitudes. For arbitrary values of viscosity and density ratios, and for a range of values of a rotational Reynolds number, we investigate how the time-dependent angular velocity and inertia affect the important finger competition events that traditionally arise in rotating Hele-Shaw flows.

  8. Angular momentum projection of tilted axis rotating states

    Energy Technology Data Exchange (ETDEWEB)

    Oi, M; Onishi, N; Tajima, N [Tokyo Univ. (Japan); Horibata, T

    1998-03-01

    We applied an exact angular momentum projection to three dimensional cranked HFB (3d-CHFB) states. Tilted axis rotating states (TAR) and principal axis rotating states (PAR) are compared. It is shown that TAR is more adequate than PAR for description of the back bending phenomena driven by tilted rotation or wobbling motion. (author)

  9. Evolution of rotating stars. III. Predicted surface rotation velocities for stars which conserve total angular momentum

    International Nuclear Information System (INIS)

    Endal, A.S.; Sofia, S.

    1979-01-01

    Predicted surface rotation velocities are presented for Population I stars at 10, 7, 5, 3, and 1.5M/sub sun/. The surface velocities have been computed for three different cases of angular momentum redistribution: no radial redistribution (rotation on decoupled shells), complete redistribution (rigid-body rotation), and partial redistribution as predicted by detailed consideration of circulation currents in rotation stars. The velocities for these cases are compared to each other and to observed stellar rotation rates (upsilon sin i).Near the main sequence, rotational effects can substantially reduce the moment of inertia of a star, so nonrotating models consistently underestimate the expected velocities for evolving stars. The magnitude of these effects is sufficient to explain the large numbers of Be stars and, perhaps, to explain the bimodal distribution of velocities observed for the O stars.On the red giant branch, angular momentum redistribution reduces the surface velocity by a factor of 2 or more, relative to the velocity expected for no radial redistribution. This removes the discrepancy between predicted and observed rotation rates for the K giants and makes it unlikely that these stars lose significant amounts of angular momentum by stellar winds. Our calculations indicate that improved observations (by the Fourier-transform technique) of the red giants in the Hyades cluster can be used to determine how angular momentum is redistributed by convection

  10. Optical Torque Wrench: Angular Trapping, Rotation, and Torque Detection of Quartz Microparticles

    Science.gov (United States)

    La Porta, Arthur; Wang, Michelle D.

    2004-05-01

    We describe an apparatus that can measure the instantaneous angular displacement and torque applied to a quartz particle which is angularly trapped. Torque is measured by detecting the change in angular momentum of the transmitted trap beam. The rotational Brownian motion of the trapped particle and its power spectral density are used to determine the angular trap stiffness. The apparatus features a feedback control that clamps torque or other rotational quantities. The torque sensitivity demonstrated is ideal for the study of known biological molecular motors.

  11. Path integral of the angular momentum eigenstates evolving with the parameter linked with rotation angle under the space rotation transformation

    International Nuclear Information System (INIS)

    Zhang Zhongcan; Hu Chenguo; Fang Zhenyun

    1998-01-01

    The authors study the method which directly adopts the azimuthal angles and the rotation angle of the axis to describe the evolving process of the angular momentum eigenstates under the space rotation transformation. The authors obtain the angular momentum rotation and multi-rotation matrix elements' path integral which evolves with the parameter λ(0→θ,θ the rotation angle), and establish the general method of treating the functional (path) integral as a normal multi-integrals

  12. Manifest rotation symmetric expressions for angular momentum eigenfunctions

    International Nuclear Information System (INIS)

    Eeg, J.O.; Wroldsen, J.

    1983-01-01

    Manifest rotation symmetric expressions for eigenfunctions for spin s, orbital angular momentum l and total angular momentum j = l+s, .... , /l-s/ in terms of (2j+1) x (2s+1) multipole transition matrices (MTM) is given. These matrices, which are irreducible tensor matrices, have an algebra together with ordinary spin matrices for spin s and spin j. Explicit expressions for MTM's and their algebra are given for angular momenta <-3. By means of some examples it is shown that within this formalism angular integrations in central field problems will be simplified considerably. Thus the formalism turns out to be very useful for instance for calculations within the MIT-bag and also within spin-spin interactions in atomic physics. (Auth.)

  13. Minimizing the translation error in the application of an oblique single-cut rotation osteotomy: Where to cut?

    NARCIS (Netherlands)

    Dobbe, Johannes G. G.; Strackee, Simon D.; Streekstra, Geert J.

    2017-01-01

    An oblique single cut rotation osteotomy enables correcting angular bone alignment in the coronal, sagittal and transverse planes, with just a single oblique osteotomy, and by rotating one bone segment in the osteotomy plane. However, translational malalignment is likely to exist if the bone is

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

    Science.gov (United States)

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

    2017-06-01

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

  15. A systematic review of the angular values obtained by computerized photogrammetry in sagittal plane: a proposal for reference values.

    Science.gov (United States)

    Krawczky, Bruna; Pacheco, Antonio G; Mainenti, Míriam R M

    2014-05-01

    Reference values for postural alignment in the coronal plane, as measured by computerized photogrammetry, have been established but not for the sagittal plane. The objective of this study is to propose reference values for angular measurements used for postural analysis in the sagittal plane for healthy adults. Electronic databases (PubMed, BVS, Cochrane, Scielo, and Science Direct) were searched using the following key words: evaluation, posture, photogrammetry, and software. Articles published between 2006 and 2012 that used the PAS/SAPO (postural assessment software) were selected. Another inclusion criterion was the presentation of, at least, one of the following measurements: head horizontal alignment, pelvic horizontal alignment, hip angle, vertical alignment of the body, thoracic kyphosis, and lumbar lordosis. Angle samples of the selected articles were grouped 2 by 2 in relation to an overall average, which made possible total average, variance, and SD calculations. Six articles were included, and the following average angular values were found: 51.42° ± 4.87° (head horizontal alignment), -12.26° ± 5.81° (pelvic horizontal alignment), -6.40° ± 3.86° (hip angle), and 1.73° ± 0.94° (vertical alignment of the body). None of the articles contained the measurements for thoracic kyphosis and lumbar lordosis. The reference values can be adopted as reference for postural assessment in future researches if the same anatomical points are considered. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  16. Contributions of individual muscles to the sagittal- and frontal-plane angular accelerations of the trunk in walking.

    Science.gov (United States)

    Klemetti, Rudolf; Steele, Katherine M; Moilanen, Petro; Avela, Janne; Timonen, Jussi

    2014-07-18

    This study was conducted to analyze the unimpaired control of the trunk during walking. Studying the unimpaired control of the trunk reveals characteristics of good control. These characteristics can be pursued in the rehabilitation of impaired control. Impaired control of the trunk during walking is associated with aging and many movement disorders. This is a concern as it is considered to increase fall risk. Muscles that contribute to the trunk control in normal walking may also contribute to it under perturbation circumstances, attempting to prevent an impending fall. Knowledge of such muscles can be used to rehabilitate impaired control of the trunk. Here, angular accelerations of the trunk induced by individual muscles, in the sagittal and frontal planes, were calculated using 3D muscle-driven simulations of seven young healthy subjects walking at free speed. Analysis of the simulations demonstrated that the abdominal and back muscles displayed large contributions throughout the gait cycle both in the sagittal and frontal planes. Proximal lower-limb muscles contributed more than distal muscles in the sagittal plane, while both proximal and distal muscles showed large contributions in the frontal plane. Along with the stance-limb muscles, the swing-limb muscles also exhibited considerable contribution. The gluteus medius was found to be an important individual frontal-plane control muscle; enhancing its function in pathologies could ameliorate gait by attenuating trunk sway. In addition, since gravity appreciably accelerated the trunk in the frontal plane, it may engender excessive trunk sway in pathologies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Control of Rotational Energy and Angular Momentum Orientation with an Optical Centrifuge

    Science.gov (United States)

    Ogden, Hannah M.; Murray, Matthew J.; Mullin, Amy S.

    2017-04-01

    We use an optical centrifuge to trap and spin molecules to an angular frequency of 30 THz with oriented angular momenta and extremely high rotational energy and then investigate their subsequent collision dynamics with transient high resolution IR spectroscopy. The optical centrifuge is formed by combining oppositely-chirped pulses of 800 nm light, and overlapping them spatially and temporally. Polarization-sensitive Doppler-broadened line profiles characterize the anisotropic kinetic energy release of the super rotor molecules, showing that they behave like molecular gyroscopes. Studies are reported for collisions of CO2 super rotors with CO2, He and Ar. These studies reveal how mass, velocity and rotational adiabaticity impact the angular momentum relaxation and reorientation. Quantum scattering calculations provide insight into the J-specific collision cross sections that control the relaxation. NSF-CHE 105 8721.

  18. Knee joint passive stiffness and moment in sagittal and frontal planes markedly increase with compression.

    Science.gov (United States)

    Marouane, H; Shirazi-Adl, A; Adouni, M

    2015-01-01

    Knee joints are subject to large compression forces in daily activities. Due to artefact moments and instability under large compression loads, biomechanical studies impose additional constraints to circumvent the compression position-dependency in response. To quantify the effect of compression on passive knee moment resistance and stiffness, two validated finite element models of the tibiofemoral (TF) joint, one refined with depth-dependent fibril-reinforced cartilage and the other less refined with homogeneous isotropic cartilage, are used. The unconstrained TF joint response in sagittal and frontal planes is investigated at different flexion angles (0°, 15°, 30° and 45°) up to 1800 N compression preloads. The compression is applied at a novel joint mechanical balance point (MBP) identified as a point at which the compression does not cause any coupled rotations in sagittal and frontal planes. The MBP of the unconstrained joint is located at the lateral plateau in small compressions and shifts medially towards the inter-compartmental area at larger compression forces. The compression force substantially increases the joint moment-bearing capacities and instantaneous angular rigidities in both frontal and sagittal planes. The varus-valgus laxities diminish with compression preloads despite concomitant substantial reductions in collateral ligament forces. While the angular rigidity would enhance the joint stability, the augmented passive moment resistance under compression preloads plays a role in supporting external moments and should as such be considered in the knee joint musculoskeletal models.

  19. Can a Single Sagittal Magnetic Resonance Imaging Slice Represent Whole Fatty Infiltration in Chronic Rotator Cuff Tears at the Supraspinatus?

    Science.gov (United States)

    Lee, Yong-Beom; Yang, Cheol-Jung; Li, Cheng Zhen; Zhuan, Zhong; Kwon, Seung-Cheol; Noh, Kyu-Cheol

    2018-03-01

    This study aimed to investigate whether fatty infiltration (FI) measured on a single sagittal magnetic resonance imaging (MRI) slice can represent FI of the whole supraspinatus muscle. This study retrospectively reviewed the MRIs of 106 patients (age 50-79 years) divided into three rotator cuff tear-size groups: medium, large, and massive. Fat mass and muscle mass on all T1-weighted sagittal MRI scans (FA and MA) were measured. Of the total MRI scans, the Y-view was defined as the most lateral image of the junction of the scapular spine with the scapular body on the oblique sagittal T1-weighted image. Fat mass and muscle mass seen on this Y-view single slice were recorded as F1 and M1, respectively. Fat mass and muscle mass were also assessed on MRI scans lateral and medial to the Y-view. The means of fat mass and muscle mass on these three slices were recorded as F3 and M3, respectively. Average FI ratios (fat mass/muscle mass) of the three assessment methods (F1/M1, FA/MA, and F3/M3) were compared. Intraclass correlation coefficients (ICCs) were calculated for inter- and intraobserver reliability. ICCs showed higher reliability (> 0.8) for all measurements. F1/M1 values were not statistically different from FA/MA and F3/M3 values ( p > 0.05), except in males with medium and large tears. F3/M3 and FA/MA were not statistically different. The difference between F1/M1 and FA/MA did not exceed 2%. A single sagittal MRI slice can represent the whole FI in chronic rotator cuff tears, except in some patient groups. We recommend measurement of FI using a single sagittal MRI slice, given the effort required for repeated measurements.

  20. Sorting photons of different rotational Doppler shifts (RDS) by orbital angular momentum of single-photon with spin-orbit-RDS entanglement.

    Science.gov (United States)

    Chen, Lixiang; She, Weilong

    2008-09-15

    We demonstrate that single photons from a rotating q-plate exhibit an entanglement in three degrees of freedom of spin, orbital angular momentum, and the rotational Doppler shift (RDS) due to the nonconservation of total spin and orbital angular momenta. We find that the rotational Doppler shift deltaomega = Omega((delta)s + deltal) , where s, l and Omega are quantum numbers of spin, orbital angular momentum, and rotating velocity of the q-plate, respectively. Of interest is that the rotational Doppler shift directly reflects the rotational symmetry of q-plates and can be also expressed as deltaomega = (Omega)n , where n = 2(q-1) denotes the fold number of rotational symmetry. Besides, based on this single-photon spin-orbit-RDS entanglement, we propose an experimental scheme to sort photons of different frequency shifts according to individual orbital angular momentum.

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

    Directory of Open Access Journals (Sweden)

    Jiayu Zhang

    2018-05-01

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

  2. Statistical orientation fluctuations: constant angular momentum versus constant rotational frequency constraints

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, A L [Tulane Univ., New Orleans, LA (United States)

    1992-08-01

    Statistical orientation fluctuations are calculated with two alternative assumptions: the rotational frequency remains constant as the shape orientation fluctuates; and, the average angular momentum remains constant as the shape orientation fluctuates. (author). 2 refs., 3 figs.

  3. Angular Momentum Transport in Turbulent Flow between Independently Rotating Cylinders

    International Nuclear Information System (INIS)

    Paoletti, M. S.; Lathrop, D. P.

    2011-01-01

    We present measurements of the angular momentum flux (torque) in Taylor-Couette flow of water between independently rotating cylinders for all regions of the (Ω 1 , Ω 2 ) parameter space at high Reynolds numbers, where Ω 1 (Ω 2 ) is the inner (outer) cylinder angular velocity. We find that the Rossby number Ro=(Ω 1 -Ω 2 )/Ω 2 fully determines the state and torque G as compared to G(Ro=∞)≡G ∞ . The ratio G/G ∞ is a linear function of Ro -1 in four sections of the parameter space. For flows with radially increasing angular momentum, our measured torques greatly exceed those of previous experiments [Ji et al., Nature (London), 444, 343 (2006)], but agree with the analysis of Richard and Zahn [Astron. Astrophys. 347, 734 (1999)].

  4. Angular momentum transfer in primordial discs and the rotation of the first stars

    Science.gov (United States)

    Hirano, Shingo; Bromm, Volker

    2018-05-01

    We investigate the rotation velocity of the first stars by modelling the angular momentum transfer in the primordial accretion disc. Assessing the impact of magnetic braking, we consider the transition in angular momentum transport mode at the Alfvén radius, from the dynamically dominated free-fall accretion to the magnetically dominated solid-body one. The accreting protostar at the centre of the primordial star-forming cloud rotates with close to breakup speed in the case without magnetic fields. Considering a physically motivated model for small-scale turbulent dynamo amplification, we find that stellar rotation speed quickly declines if a large fraction of the initial turbulent energy is converted to magnetic energy (≳ 0.14). Alternatively, if the dynamo process were inefficient, for amplification due to flux freezing, stars would become slow rotators if the pre-galactic magnetic field strength is above a critical value, ≃10-8.2 G, evaluated at a scale of nH = 1 cm-3, which is significantly higher than plausible cosmological seed values (˜10-15 G). Because of the rapid decline of the stellar rotational speed over a narrow range in model parameters, the first stars encounter a bimodal fate: rapid rotation at almost the breakup level, or the near absence of any rotation.

  5. Determination of a sagittal plane axis of rotation for a dynamic office chair.

    Science.gov (United States)

    Bauer, C M; Rast, F M; Böck, C; Kuster, R P; Baumgartner, D

    2018-10-01

    This study investigated the location of the axis of rotation in sagittal plane movement of the spine in a free sitting condition to adjust the kinematics of a mobile seat for a dynamic chair. Dynamic office chairs are designed to avoid continuous isometric muscle activity, and to facilitate increased mobility of the back during sitting. However, these chairs incorporate increased upper body movement which could distract office workers from the performance of their tasks. A chair with an axis of rotation above the seat would facilitate a stable upper back during movements of the lower back. The selection of a natural kinematic pattern is of high importance in order to match the properties of the spine. Twenty-one participants performed four cycles of flexion and extension of the spine during an upper arm hang on parallel bars. The location of the axis of rotation relative to the seat was estimated using infrared cameras and reflective skin markers. The median axis of rotation across all participants was located 36 cm above the seat for the complete movement and 39 cm for both the flexion and extension phases, each with an interquartile range of 20 cm. There was no significant effect of the movement direction on the location of the axis of rotation and only a weak, non-significant correlation between body height and the location of the axis of rotation. Individual movement patterns explained the majority of the variance. The axis of rotation for a spinal flexion/extension movement is located above the seat. The recommended radius for a guide rail of a mobile seat is between 36 cm and 39 cm. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Angular Momentum of a Bose-Einstein Condensate in a Synthetic Rotational Field

    Science.gov (United States)

    Qu, Chunlei; Stringari, Sandro

    2018-05-01

    By applying a position-dependent detuning to a spin-orbit-coupled Hamiltonian with equal Rashba and Dresselhaus coupling, we exploit the behavior of the angular momentum of a harmonically trapped Bose-Einstein condensed atomic gas and discuss the distinctive role of its canonical and spin components. By developing the formalism of spinor hydrodynamics, we predict the precession of the dipole oscillation caused by the synthetic rotational field, in analogy with the precession of the Foucault pendulum, the excitation of the scissors mode, following the sudden switching off of the detuning, and the occurrence of Hall-like effects. When the detuning exceeds a critical value, we observe a transition from a vortex free, rigidly rotating quantum gas to a gas containing vortices with negative circulation which results in a significant reduction of the total angular momentum.

  7. Demonstrating the Conservation of Angular Momentum Using Model Cars Moving along a Rotating Rod

    Science.gov (United States)

    Abdul-Razzaq, Wathiq; Golubovic, Leonardo

    2013-01-01

    We have developed an exciting non-traditional experiment for our introductory physics laboratories to help students to understand the principle of conservation of angular momentum. We used electric toy cars moving along a long rotating rod. As the cars move towards the centre of the rod, the angular velocity of this system increases.…

  8. Super-resolution and ultra-sensitivity of angular rotation measurement based on SU(1,1) interferometers using homodyne detection

    Science.gov (United States)

    Liu, Jun; Li, Shitao; Wei, Dong; Gao, Hong; Li, Fuli

    2018-02-01

    We theoretically explore the angular rotation measurement sensitivity of SU(1,1) interferometers with a coherent beam and a vacuum beam input by using orbital angular momentum (OAM). Compared with the OAM in an SU(2) interferometer, the SU(1,1) interferometer employing homodyne detection can further surpass the angular rotation shot noise limit \\tfrac{1}{2l\\sqrt{N}} and improve the resolution and sensitivity of angular rotation measurement. Two models are considered, one is that OAM is carried by a probe beam and the other one is a pump beam with the OAM. The sensitivity can be improved by higher OAM and nonlinear process with a large gain. The resolution can be enhanced in the case that the pump beam has OAM. Moreover, we present a brief discussion on the variation of resolution and sensitivity in the presence of photon loss.

  9. Rotational broadening and conservation of angular momentum in post-extreme horizontal branch stars

    Science.gov (United States)

    Fontaine, G.; Latour, M.

    2018-06-01

    We show that the recent realization that isolated post-extreme horizontal branch (post-EHB) stars are generally characterized by rotational broadening with values of V rot sini between 25 and 30 km s-1 can be explained as a natural consequence of the conservation of angular momentum from the previous He-core burning phase on the EHB. The progenitors of these evolved objects, the EHB stars, are known to be slow rotators with an average value of V rot sini of 7.7 km s-1. This implies significant spin-up between the EHB and post-EHB phases. Using representative evolutionary models of hot subdwarf stars, we demonstrate that angular momentum conservation in uniformly rotating structures (rigid-body rotation) boosts that value of the projected equatorial rotation speed by a factor 3.6 by the time the model has reached the region of the surface gravity-effective temperature plane where the newly-studied post-EHB objects are found. This is exactly what is needed to account for their observed atmospheric broadening. We note that the decrease of the moment of inertia causing the spin-up is mostly due to the redistribution of matter that produces more centrally-condensed structures in the post-EHB phase of evolution, not to the decrease of the radius per se.

  10. Angular momentum independence of the entropy sum and entropy product for AdS rotating black holes in all dimensions

    Directory of Open Access Journals (Sweden)

    Hang Liu

    2016-08-01

    Full Text Available In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions d>4 with at least one rotation parameter ai=0, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions (d>4 and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affect the angular momentum-free of entropy sum and product but the criterion for angular momentum-independence of entropy product will be affected.

  11. Angular momentum in general relativity. II. Perturbations of a rotating black hole

    Energy Technology Data Exchange (ETDEWEB)

    Prior, C R [Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics

    1977-06-30

    The definition of angular momentum proposed in part I of this series (Prior. Proc. R. Soc. Lond.; A354:379 (1977)) is investigated when applied to rotating black holes. It is shown how to use the formula to evaluate the angular momentum of a stationary black hole. This acts as a description of a background space on which the effect of first matter and then gravitational perturbations is considered. The latter are of most interest and the rate of change of angular momentum, dJ/dt, is found as an expression in the shear induced in the event horizon by the perturbation and in its time integral. Teukolsky's solutions (Astrophys. J.; 185:635 (1973)) for the perturbed component of the Weyl tensor are then used to find this shear and hence to give an exact answer for dJ/dt. One of the implications of the result is a direct verification of Bekenstein's formula (Phys. Rev.; 7D:949 (1973)) relating in a simple way the rate of change of angular momentum to the rate of change of mass caused by a plane wave. A more general expression is also given for dM/dt. Considering only stationary perturbations, it is shown how to generalize the definition of angular momentum so as to include information about its direction as well. Three problems are particularly discussed - a single moon, two or more moons and a ring of matter causing the perturbation - since they provide illustrations of all the main features of the black hole's behaviour. In every case it is found that the black hole realigns its axis of rotation so that the final configuration is axisymmetric if possible; otherwise is slows down completely to reach a static state.

  12. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material.

    Science.gov (United States)

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-09-01

    When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure.

  13. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material

    International Nuclear Information System (INIS)

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-01-01

    When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5° angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure. (author)

  14. Whole-body angular momentum during stair ascent and descent.

    Science.gov (United States)

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

    2014-04-01

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

  15. Phase transition and angular momentum dependence of correlations in the rotational spectra of Ne20 and Ne22

    International Nuclear Information System (INIS)

    Satpathy, L.; Schmid, K.W.; Krewald, S.; Faessler, A.

    1974-01-01

    Multi-Configuration-Hartree-Fock (MCHF) calculations with angular momentum projection before the variation of the internal degree of freedom have been performed for the nuclei Ne 20 and Ne 22 . This procedure yields different correlated intrinsic states for the different members of a rotational band. Thus, the angular momentum dependence of correlations has been studied. Experimentally, the ground state spectra of Ne 20 and Ne 22 show properties similar to the phase transitions observed in some rare earth nuclei which have been well reproduced through the present calculations. The calculated spectra show a significant improvement compared to the ones obtained by variation before the angular momentum projection is effected. (author)

  16. Symmetry broken and restored coupled-cluster theory: I. Rotational symmetry and angular momentum

    International Nuclear Information System (INIS)

    Duguet, T

    2015-01-01

    We extend coupled-cluster (CC) theory performed on top of a Slater determinant breaking rotational symmetry to allow for the exact restoration of the angular momentum at any truncation order. The main objective relates to the description of near-degenerate finite quantum systems with an open-shell character. As such, the newly developed many-body formalism offers a wealth of potential applications and further extensions dedicated to the ab initio description of, e.g., doubly open-shell atomic nuclei and molecule dissociation. The formalism, which encompasses both single-reference CC theory and projected Hartree–Fock theory as particular cases, permits the computation of usual sets of connected diagrams while consistently incorporating static correlations through the highly non-perturbative restoration of rotational symmetry. Interestingly, the yrast spectroscopy of the system, i.e. the lowest energy associated with each angular momentum, is accessed within a single calculation. A key difficulty presently overcome relates to the necessity to handle generalized energy and norm kernels for which naturally terminating CC expansions could be eventually obtained. The present work focuses on SU(2) but can be extended to any (locally) compact Lie group and to discrete groups, such as most point groups. In particular, the formalism will be soon generalized to U(1) symmetry associated with particle number conservation. This is relevant to Bogoliubov CC theory that was recently applied to singly open-shell nuclei. (paper)

  17. [Extramedullary fixation combined with intramedullary fixation in the surgical reduction of sagittal mandibular condylar fractures].

    Science.gov (United States)

    Chuanjun, Chen; Xiaoyang, Chen; Jing, Chen

    2016-10-01

    This study aimed to evaluate the clinical effect of extramedullary fixation combined with intramedullary fixation during the surgical reduction of sagittal mandibular condylar fractures. Twenty-four sagittal fractures of the mandibular condyle in18 patients were fixed by two appliances: intramedullary with one long-screw osteosynthesis or Kirschner wire and extramedullary with one micro-plate. The radiologically-recorded post-operative stability-associated com-plications included the screw/micro-plate loosening, micro-plate twisting, micro-plate fractures, and fragment rotation. The occluding relations, the maximalinter-incisal distances upon mouth opening, and the mandibular deflection upon mouth opening were evaluated based on follow-up clinical examination. Postoperative panoramic X-ray and CT scans showed good repositioning of the fragment, with no redislocation or rotation, no screw/plate loosening, and no plate-twisting or fracture. Clinical examination showed that all patients regained normal mandibular movements, ideal occlusion, and normal maximal inter-incisal distances upon mouth opening. Extramedullary fixation combined with intramedullary fixation is highly recommended for sagittal condylar fractures because of the anti-rotation effect of the fragment and the reasonable place-ment of the fixation appliances.

  18. Accelerated rotation with orbital angular momentum modes

    CSIR Research Space (South Africa)

    Schulze, C

    2015-04-01

    Full Text Available . As the angular acceleration takes place in a bounded space, the azimuthal degree of freedom, such fields accelerate periodically as they propagate. Notably, the amount of angular acceleration is not limited by paraxial considerations, may be tailored for large...

  19. Eilenberger equation for rotating superfluid 3He and calculation of the upper critical angular velocity Ω/sub c/2

    International Nuclear Information System (INIS)

    Schopohl, N.

    1980-01-01

    On the basis of Gorkov's formulation of superconductivity theory, generalized Eilenberger equations are derived which apply to rotating superfluid 3 He in the presence of a magnetic field h and finite superflow v. In analyogy to conventional type II superconductors, the possibility of vortex solutions in discussed. An implicit equation determining the upper critical angular velocity Ω/sub c/2 as a function of temperature T, magnetic field h, and superflow v parallel to the rotation axis is-inferred from the linearized Eilenberger equations. In contrast to the case of slowly rotating 3 He-A, the solution of the eigenvalue problem determining the order parameter Δ near the the upper critical angular velocity admits no coreless vortex no coreless solutions. The space-dependent amplitude of the order parameter is analogous to Abrikosov's vortex array solution, while the spin-orbit part is given either by a polar-state type or an Anderson-Brinkman-Morel (ABM)-state-type eigensolution. Among the possible eigensolutions the polar-state type yields for vanishing superflow v the highest critical rotation frequency. For finite superflow v parallel to the rotation axis, however, the ABM-state-type solution is stabilized in comparison to the polar state for Vertical BarvVertical Bar> or approx. =0.2π(Tc/sub c/0/T/sub F/)v/sub f/ at zero temperature

  20. Rotation of intramedullary alignment rods affects distal femoral cutting plane in total knee arthroplasty.

    Science.gov (United States)

    Maderbacher, Günther; Matussek, Jan; Keshmiri, Armin; Greimel, Felix; Baier, Clemens; Grifka, Joachim; Maderbacher, Hermann

    2018-02-17

    Intramedullary rods are widely used to align the distal femoral cut in total knee arthroplasty. We hypothesised that both coronal (varus/valgus) and sagittal (extension/flexion) cutting plane are affected by rotational changes of intramedullary femoral alignment guides. Distal femoral cuts using intramedullary alignment rods were simulated by means of a computer-aided engineering software in 4°, 6°, 8°, 10°, and 12° of valgus in relation to the femoral anatomical axis and 4° extension, neutral, as well as 4°, 8°, and 12° of flexion in relation to the femoral mechanical axis. This reflects the different angles between anatomical and mechanical axis in coronal and sagittal planes. To assess the influence of rotation of the alignment guide on the effective distal femoral cutting plane, all combinations were simulated with the rod gradually aligned from 40° of external to 40° of internal rotation. Rotational changes of the distal femoral alignment guides affect both the coronal and sagittal cutting planes. When alignment rods are intruded neutrally with regards to sagittal alignment, external rotation causes flexion, while internal rotation causes extension of the sagittal cutting plane. Simultaneously the coronal effect (valgus) decreases resulting in an increased varus of the cutting plane. However, when alignment rods are intruded in extension or flexion partly contradictory effects are observed. Generally the effect increases with the degree of valgus preset, rotation and flexion. As incorrect rotation of intramedullary alignment guides for distal femoral cuts causes significant cutting errors, exact rotational alignment is crucial. Coronal cutting errors in the distal femoral plane might result in overall leg malalignment, asymmetric extension gaps and subsequent sagittal cutting errors.

  1. Interfraction Prostate Rotation Determined from In-Room Computerized Tomography Images

    International Nuclear Information System (INIS)

    Owen, Rebecca; Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian

    2011-01-01

    Fiducial markers (FMs) are commonly used as a correction technique for interfraction translations of the prostate. The aim of this investigation was to determine the magnitude of prostate rotations using 2 methods: FM coordinates and the anatomical border of the prostate and rectum. Daily computed tomography (CT) scans (n = 346) of 10 prostate cancer patients with 3 implanted FMs were acquired using the CT on rails. FM coordinates were used to determine rotation in the sagittal, transverse, and coronal planes, and CT contours of the prostate and rectum were used to determine rotation along the sagittal plane. An adaptive technique based on a subset of images (n = 6; planning and first 5 treatment CTs) to reduce systematic rotation errors in the sagittal plane was tested. The standard deviation (SD) of systematic rotation from FM coordinates was 7.6 o , 7.7 o , and 5.0 o in the sagittal, transverse and coronal planes. The corresponding SD of random error was 10.2 o , 15.8 o , and 6.5 o . Errors in the sagittal plane, determined from prostate and rectal contours, were 10.1 o (systematic) and 7.7 o (random). These results did not correlate with rotation computed from FM coordinates (r = -0.017; p = 0.753, n = 337). The systematic error could be reduced by 43% to 5.6 o when the mean prostate position was estimated from 6 CT scans. Prostate rotation is a significant source of error that appears to be more accurately determined using the anatomical border of the prostate and rectum rather than FMs, thus highlighting the utility of CT image guidance.

  2. Role of angular momentum and cosmic censorship in (2+1)-dimensional rotating shell collapse

    International Nuclear Information System (INIS)

    Mann, Robert B.; Oh, John J.; Park, Mu-In

    2009-01-01

    We study the gravitational collapse problem of rotating shells in three-dimensional Einstein gravity with and without a cosmological constant. Taking the exterior and interior metrics to be those of stationary metrics with asymptotically constant curvature, we solve the equations of motion for the shells from the Darmois-Israel junction conditions in the corotating frame. We study various collapse scenarios with arbitrary angular momentum for a variety of geometric configurations, including anti-de Sitter, de Sitter, and flat spaces. We find that the collapsing shells can form a BTZ black hole, a three-dimensional Kerr-dS spacetime, and an horizonless geometry of point masses under certain initial conditions. For pressureless dust shells, the curvature singularity is not formed due to the angular momentum barrier near the origin. However when the shell pressure is nonvanishing, we find that for all types of shells with polytropic-type equations of state (including the perfect fluid and the generalized Chaplygin gas), collapse to a naked singularity is possible under generic initial conditions. We conclude that in three dimensions angular momentum does not in general guard against violation of cosmic censorship.

  3. A morphometric investigation on breed-specific features affecting sagittal rotational and lateral bending mobility in the canine cervical spine (c3-c7).

    Science.gov (United States)

    Breit, S; Künzel, W

    2004-08-01

    Vertebral and inter-vertebral parameters obtained in large breeds (n = 74), small breeds (n = 35), and Dachshunds (n = 30) were compared to reveal potential differences in the range of motion of the cervical spine between these three groups of breeds. Body size normalized dimensions of vertebral and inter-vertebral parameters and correlations between these indicate large canine breeds to have a tendency towards higher range of motion in sagittal rotation and lateral bending compared with Dachshunds and small breeds. Higher mobility in large breeds is based on significantly (P inter-vertebral discs, wider but shorter cranial and caudal articular surfaces, larger differences in width between caudal and cranial joining facets (compared with Dachshunds from C3/4 to C6/7, compared with small breeds from C4/5 to C5/6), and larger differences in length between caudal and cranial joining facets. Large differences in width between caudal and cranial joining facets were associated with small distances between the most medial (C3/4 to C6/7) and lateral (C3/4 to C5/6) aspects of the articular surfaces as well as with small differences in length between caudal and cranial joining facets (C3/4 to C5/6). This suggests that from C3/4 to C5/6 a higher range of motion in lateral bending is coupled to a lower range of motion in sagittal rotation. The present findings contribute also to explain the higher incidence of degenerative lesions of the cervical spine in large dogs.

  4. Rotating Wavepackets

    Science.gov (United States)

    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…

  5. Mimicking Faraday rotation to sort the orbital angular momentum of light.

    Science.gov (United States)

    Zhang, Wuhong; Qi, Qianqian; Zhou, Jie; Chen, Lixiang

    2014-04-18

    The efficient separation of the orbital angular momentum (OAM) is essential to both the classical and quantum applications with twisted photons. Here we devise and demonstrate experimentally an efficient method of mimicking the Faraday rotation to sort the OAM based on the OAM-to-polarization coupling effect induced by a modified Mach-Zehnder interferometer. Our device is capable of sorting the OAM of positive and negative numbers, as well as their mixtures. Furthermore, we report the first experimental demonstration to sort optical vortices of noninteger charges. The possibility of working at the photon-count level is also shown using an electron-multiplying CCD camera. Our scheme holds promise for quantum information applications with single-photon entanglement and for high-capacity communication systems with polarization and OAM multiplexing.

  6. A Novel Permanent Magnetic Angular Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Hao Zhao

    2015-07-01

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

  7. Rotations with Rodrigues' vector

    International Nuclear Information System (INIS)

    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 to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

  8. On the angular momentum in star formation

    International Nuclear Information System (INIS)

    Horedt, G.P.

    1978-01-01

    The author discusses the rotation of interstellar clouds which are in a stage immediately before star formation. Cloud collisions seem to be the principal cause of the observed rotation of interstellar clouds. The rotational motion of the clouds is strongly influenced by turbulence. Theories dealing with the resolution of the angular momentum problem in star formation are classified into five major groups. The old idea that the angular momentum of an interstellar cloud passes during star formation into the angular momentum of double star systems and/or circumstellar clouds, is developed. It is suggested that a rotating gas cloud contracts into a ring-like structure which fragments into self-gravitating subcondensations. By collisions and gas accretion these subcondensations accrete into binary systems surrounded by circumstellar clouds. Using some rough approximations the authors find analytical expressions for the semi-major axis of the binary system and for the density of the circumstellar clouds as a function of the initial density and of the initial angular velocity of an interstellar cloud. The obtained values are well within the observational limits. (Auth.)

  9. On the Angular Momentum Loss of Tropical Cyclones: An f-Plane Approximation

    Science.gov (United States)

    Kang, Hyun-Gyu; Cheong, Hyeong-Bin; Kim, Won-Ho

    2018-02-01

    The angular momentum for ideal axisymmetric tropical cyclones on the f-plane is investigated with a focus on the total-volume integrated quantity. Budget analysis of the momentum equation at cylindrical coordinates shows that a tropical cyclone loses angular momentum during its development and mature stages due to the dynamical difference between the viscous inward-flow near the surface and the angular momentum conserving outward-flow aloft. The total relative angular momentum of a tropical cyclone, as a result, can be negative (i.e., implying anticyclonic rotation as a whole) despite intense cyclonic wind in the tropospheric layers. This anticyclonic rotation was measured in terms of the super-rotation ratio, the ratio of total relative angular momentum to the planetary angular momentum. Simulations with the numerical model of Weather Research and Forecasting (WRF) version 3.4.1 was found to be in favor of the theoretical angular-momentum budget analysis. It was revealed in the numerical simulations that the super-rotation ratio was negative, indicating a sub-rotation, as was predicted by analysis. The sub-rotation ratio was found to be less than one percent for typical tropical cyclones. To show the angular momentum decrease even in the decaying stage, numerical simulations where the thermal forcing by sea surface temperature switched off in the mature stage were carried out. In support of the angular momentum budget analysis, the results indicated that the angular momentum also decreases for a while soon after the forcing was eliminated.

  10. Design and Implementation of a Digital Angular Rate Sensor

    Directory of Open Access Journals (Sweden)

    Zhen Peng

    2010-10-01

    Full Text Available With the aim of detecting the attitude of a rotating carrier, the paper presents a novel, digital angular rate sensor. The sensor consists of micro-sensing elements (gyroscope and accelerometer, signal processing circuit and micro-processor (DSP2812. The sensor has the feature of detecting three angular rates of a rotating carrier at the same time. The key techniques of the sensor, including sensing construction, sensing principles, and signal processing circuit design are presented. The test results show that the sensor can sense rolling, pitch and yaw angular rate at the same time and the measurement error of yaw (or pitch angular rate and rolling rate of the rotating carrier is less than 0.5%.

  11. Angular-momentum-projected cranked HFB approach to the study of nuclear rotations

    International Nuclear Information System (INIS)

    Wuest, E.; Ansari, A.; Mosel, U.

    1985-01-01

    Employing a pairing-plus-quadrupole interaction hamiltonian and projecting out good angular momentum states from the cranked Hartree-Fock-Bogoliubov (CHFB) intrinsic wave functions the yrast spectra of 158 Dy and 168 Yb are calculated up to moderately high spins (Isub(max)=16) as to include the backbending region. Then the variation of pairing correlation, g-factor and rotational alignment of neutron spin as a function of total angular momentum is studied. The effect of particle number projection on the spin-projected CHFB wave functions is also investigated and is found to be unimportant for the calculation of g-factors. On the other hand, corrections of the excitation energies for number fluctuations in the CHFB wave functions are essential. Furthermore, looking at the distribution of the total projection quantum number K in various cranking wave functions we are able to throw some light on the Knot=0 nature of the aligned s-band. A variation-after-spin projection calculation strictly for the axial shape, without cranking, is also carried out for both the nuclei considered here. In the low-spin region this numerically 'cheaper' scheme produces energy spectra similar to that of the CHFB method, and may thus be used to readjust the interaction parameters. (orig.)

  12. Rotated alphanumeric characters do not automatically activate frontoparietal areas subserving mental rotation

    DEFF Research Database (Denmark)

    Weiss, Michael M; Wolbers, Thomas; Peller, Martin

    2008-01-01

    Functional neuroimaging studies have identified a set of areas in the intraparietal sulcus and dorsal precentral cortex which show a linear increase in activity with the angle of rotation across a variety of mental rotation tasks. This linear increase in activity with angular disparity suggests t...... modulated by angular disparity during the stimulus categorization task. These results suggest that at least for alphanumerical characters, areas implicated in mental rotation will only be called into action if the task requires a rotational transformation....

  13. Maple procedures for the coupling of angular momenta. IX. Wigner D-functions and rotation matrices

    Science.gov (United States)

    Pagaran, J.; Fritzsche, S.; Gaigalas, G.

    2006-04-01

    The Wigner D-functions, Dpqj(α,β,γ), are known for their frequent use in quantum mechanics. Defined as the matrix elements of the rotation operator Rˆ(α,β,γ) in R and parametrized in terms of the three Euler angles α, β, and γ, these functions arise not only in the transformation of tensor components under the rotation of the coordinates, but also as the eigenfunctions of the spherical top. In practice, however, the use of the Wigner D-functions is not always that simple, in particular, if expressions in terms of these and other functions from the theory of angular momentum need to be simplified before some computations can be carried out in detail. To facilitate the manipulation of such Racah expressions, here we present an extension to the RACAH program [S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51] in which the properties and the algebraic rules of the Wigner D-functions and reduced rotation matrices are implemented. Care has been taken to combine the standard knowledge about the rotation matrices with the previously implemented rules for the Clebsch-Gordan coefficients, Wigner n-j symbols, and the spherical harmonics. Moreover, the application of the program has been illustrated below by means of three examples. Program summaryTitle of program:RACAH Catalogue identifier:ADFv_9_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADFv_9_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Catalogue identifier of previous version: ADFW, ADHW, title RACAH Journal reference of previous version(s): S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51; S. Fritzsche, S. Varga, D. Geschke, B. Fricke, Comput. Phys. Comm. 111 (1998) 167; S. Fritzsche, T. Inghoff, M. Tomaselli, Comput. Phys. Comm. 153 (2003) 424. Does the new version supersede the previous one: Yes, in addition to the spherical harmonics and recoupling coefficients, the program now supports also the occurrence of the Wigner rotation matrices in the algebraic

  14. Rotational speedups accompanying angular deceleration of a superfluid

    International Nuclear Information System (INIS)

    Campbell, L.J.

    1979-01-01

    Exact calculations of the angular deceleration of superfluid vortex arrays show momentary speedups in the angular velocity caused by coherent, multiple vortex loss at the boundary. The existence and shape of the speedups depend on the vortex friction, the deceleration rate, and the pattern symmetry. The phenomenon resembles, in several ways, that observed in pulsars

  15. The sagittal stem alignment and the stem version clearly influence the impingement-free range of motion in total hip arthroplasty: a computer model-based analysis.

    Science.gov (United States)

    Müller, Michael; Duda, Georg; Perka, Carsten; Tohtz, Stephan

    2016-03-01

    The component alignment in total hip arthroplasty influences the impingement-free range of motion (ROM). While substantiated data is available for the cup positioning, little is known about the stem alignment. Especially stem rotation and the sagittal alignment influence the position of the cone in relation to the edge of the socket and thus the impingement-free functioning. Hence, the question arises as to what influence do these parameters have on the impingement-free ROM? With the help of a computer model the influence of the sagittal stem alignment and rotation on the impingement-free ROM were investigated. The computer model was based on the CT dataset of a patient with a non-cemented THA. In the model the stem version was set at 10°/0°/-10° and the sagittal alignment at 5°/0°/-5°, which resulted in nine alternative stem positions. For each position, the maximum impingement-free ROM was investigated. Both stem version and sagittal stem alignment have a relevant influence on the impingement-free ROM. In particular, flexion and extension as well as internal and external rotation capability present evident differences. In the position intervals of 10° sagittal stem alignment and 20° stem version a difference was found of about 80° in the flexion and 50° in the extension capability. Likewise, differences were evidenced of up to 72° in the internal and up to 36° in the external rotation. The sagittal stem alignment and the stem torsion have a relevant influence on the impingement-free ROM. To clarify the causes of an impingement or accompanying problems, both parameters should be examined and, if possible, a combined assessment of these factors should be made.

  16. Whole-body angular momentum during stair walking using passive and powered lower-limb prostheses.

    Science.gov (United States)

    Pickle, Nathaniel T; Wilken, Jason M; Aldridge, Jennifer M; Neptune, Richard R; Silverman, Anne K

    2014-10-17

    Individuals with a unilateral transtibial amputation have a greater risk of falling compared to able-bodied individuals, and falling on stairs can lead to serious injuries. Individuals with transtibial amputations have lost ankle plantarflexor muscle function, which is critical for regulating whole-body angular momentum to maintain dynamic balance. Recently, powered prostheses have been designed to provide active ankle power generation with the goal of restoring biological ankle function. However, the effects of using a powered prosthesis on the regulation of whole-body angular momentum are unknown. The purpose of this study was to use angular momentum to evaluate dynamic balance in individuals with a transtibial amputation using powered and passive prostheses relative to able-bodied individuals during stair ascent and descent. Ground reaction forces, external moment arms, and joint powers were also investigated to interpret the angular momentum results. A key result was that individuals with an amputation had a larger range of sagittal-plane angular momentum during prosthetic limb stance compared to able-bodied individuals during stair ascent. There were no significant differences in the frontal, transverse, or sagittal-plane ranges of angular momentum or maximum magnitude of the angular momentum vector between the passive and powered prostheses during stair ascent or descent. These results indicate that individuals with an amputation have altered angular momentum trajectories during stair walking compared to able-bodied individuals, which may contribute to an increased fall risk. The results also suggest that a powered prosthesis provides no distinct advantage over a passive prosthesis in maintaining dynamic balance during stair walking. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Structured caustic vector vortex optical field: manipulating optical angular momentum flux and polarization rotation.

    Science.gov (United States)

    Chen, Rui-Pin; Chen, Zhaozhong; Chew, Khian-Hooi; Li, Pei-Gang; Yu, Zhongliang; Ding, Jianping; He, Sailing

    2015-05-29

    A caustic vector vortex optical field is experimentally generated and demonstrated by a caustic-based approach. The desired caustic with arbitrary acceleration trajectories, as well as the structured states of polarization (SoP) and vortex orders located in different positions in the field cross-section, is generated by imposing the corresponding spatial phase function in a vector vortex optical field. Our study reveals that different spin and orbital angular momentum flux distributions (including opposite directions) in different positions in the cross-section of a caustic vector vortex optical field can be dynamically managed during propagation by intentionally choosing the initial polarization and vortex topological charges, as a result of the modulation of the caustic phase. We find that the SoP in the field cross-section rotates during propagation due to the existence of the vortex. The unique structured feature of the caustic vector vortex optical field opens the possibility of multi-manipulation of optical angular momentum fluxes and SoP, leading to more complex manipulation of the optical field scenarios. Thus this approach further expands the functionality of an optical system.

  18. Helicons in uniform fields. II. Poynting vector and angular momenta

    Science.gov (United States)

    Stenzel, R. L.; Urrutia, J. M.

    2018-03-01

    The orbital and spin angular momenta of helicon modes have been determined quantitatively from laboratory experiments. The current density is obtained unambiguously from three dimensional magnetic field measurements. The only approximation made is to obtain the electric field from Hall Ohm's law which is usually the case for low frequency whistler modes. This allows the evaluation of the Poynting vector from which the angular momentum is obtained. Comparing two helicon modes (m = 0 and m = 1), one can separate the contribution of angular momentum of a rotating and non-rotating wave field. The orbital angular momentum is important to assess the wave-particle interaction by the transverse Doppler shift of rotating waves which has not been considered so far.

  19. Video raster stereography back shape reconstruction: a reliability study for sagittal, frontal, and transversal plane parameters.

    Science.gov (United States)

    Schroeder, J; Reer, R; Braumann, K M

    2015-02-01

    As reliability of raster stereography was proved only for sagittal plane parameters with repeated measures on the same day, the present study was aiming at investigating variability and reliability of back shape reconstruction for all dimensions (sagittal, frontal, transversal) and for different intervals. For a sample of 20 healthy volunteers, intra-individual variability (SEM and CV%) and reliability (ICC ± 95% CI) were proved for sagittal (thoracic kyphosis, lumbar lordosis, pelvis tilt angle, and trunk inclination), frontal (pelvis torsion, pelvis and trunk imbalance, vertebral side deviation, and scoliosis angle), transversal (vertebral rotation), and functional (hyperextension) spine shape reconstruction parameters for different test-retest intervals (on the same day, between-day, between-week) by means of video raster stereography. Reliability was high for the sagittal plane (pelvis tilt, kyphosis and lordosis angle, and trunk inclination: ICC > 0.90), and good to high for lumbar mobility (0.86 < ICC < 0.97). Apart from sagittal plane spinal alignment, there was a lack of certainty for a high reproducibility indicated by wider ICC confidence intervals. So, reliability was fair to high for vertebral side deviation and the scoliosis angle (0.71 < ICC < 0.95), and poor to good for vertebral rotation values as well as for frontal plane upper body and pelvis position parameters (0.65 < ICC < 0.92). Coefficients for the between-day and between-week interval were a little lower than for repeated measures on the same day. Variability (SEM) was less than 1.5° or 1.5 mm, except for trunk inclination. Relative variability (CV) was greater in global trunk position and pelvis parameters (35-98%) than in scoliosis (14-20%) or sagittal sway parameters (4-8 %). Although we found a lower reproducibility for the frontal plane, raster stereography is considered to be a reliable method for the non-invasive, three-dimensional assessment of spinal alignment in normal non

  20. Triple system HD 201433 with a SPB star component seen by BRITE - Constellation: Pulsation, differential rotation, and angular momentum transfer

    Science.gov (United States)

    Kallinger, T.; Weiss, W. W.; Beck, P. G.; Pigulski, A.; Kuschnig, R.; Tkachenko, A.; Pakhomov, Y.; Ryabchikova, T.; Lüftinger, T.; Palle, , P. L.; Semenko, E.; Handler, G.; Koudelka, O.; Matthews, J. M.; Moffat, A. F. J.; Pablo, H.; Popowicz, A.; Rucinski, S.; Wade, G. A.; Zwintz, K.

    2017-07-01

    Context. Stellar rotation affects the transport of chemical elements and angular momentum and is therefore a key process during stellar evolution, which is still not fully understood. This is especially true for massive OB-type stars, which are important for the chemical enrichment of the Universe. It is therefore important to constrain the physical parameters and internal angular momentum distribution of massive OB-type stars to calibrate stellar structure and evolution models. Stellar internal rotation can be probed through asteroseismic studies of rotationally split non radial oscillations but such results are still quite rare, especially for stars more massive than the Sun. The slowly pulsating B9V star HD 201433 is known to be part of a single-lined spectroscopic triple system, with two low-mass companions orbiting with periods of about 3.3 and 154 days. Aims: Our goal is to measure the internal rotation profile of HD 201433 and investigate the tidal interaction with the close companion. Methods: We used probabilistic methods to analyse the BRITE - Constellation photometry and radial velocity measurements, to identify a representative stellar model, and to determine the internal rotation profile of the star. Results: Our results are based on photometric observations made by BRITE - Constellation and the Solar Mass Ejection Imager on board the Coriolis satellite, high-resolution spectroscopy, and more than 96 yr of radial velocity measurements. We identify a sequence of nine frequency doublets in the photometric time series, consistent with rotationally split dipole modes with a period spacing of about 5030 s. We establish that HD 201433 is in principle a solid-body rotator with a very slow rotation period of 297 ± 76 days. Tidal interaction with the inner companion has, however, significantly accelerated the spin of the surface layers by a factor of approximately one hundred. The angular momentum transfer onto the surface of HD 201433 is also reflected by the

  1. The angular momentum dependence of complex fragment emission

    International Nuclear Information System (INIS)

    Sobtka, L.G.; Sarantites, D.G.; Li, Z.

    1987-01-01

    Large fragment (A > 4) production at high angular momentum is studied via the reaction, 200 MeV 45 Sc + 65 Cu. Comparisons of the fragment yields from this reaction (high angular momentum) to those from 93 Nb + Be (low angular momentum) are used to verify the strong angular momentum dependence of large fragment production predicted by equilibrium models. Details of the coincident γ-ray distributions not only confirm a rigidly rotating intermediate but also indicate that the widths of the primary L-wave distributions decrease with increasing symmetry in the decay channel. These data are used to test the asymmetry and L-wave dependence of emission barriers calculated from a rotating, finite range corrected, liquid drop model. 21 refs., 10 figs

  2. Occlusal plane rotation: aesthetic enhancement in mandibular micrognathia.

    Science.gov (United States)

    Rosen, H M

    1993-06-01

    Patients afflicted with extreme degrees of mandibular micrognathia typically have vertically deficient rami as well as sagittally deficient mandibular bodies. This results in deficient posterior facial height, an obtuse gonial angle, excessively steep occlusal and mandibular planes, and a compensatory increase in anterior facial height. The entire maxillomandibular complex is overrotated in a clockwise direction. Standard orthognathic surgical correction fails to address this rotational deformity. As a consequence, the achieved projection of the lower face is inadequate, posterior facial height is further reduced, and occlusal and mandibular planes remain steep. Eleven patients with severe mandibular micrognathia underwent a surgical correction involving occlusal plane rotation to its normal orientation relative to Frankfort horizontal. This was accomplished by Le Fort I osteotomy to shorten the anterior maxilla (creating open bites in seven patients and making preexisting open bites worse in four patients) and sagittal split ramus osteotomies to advance and rotate the mandibular body counterclockwise, thus closing the surgically produced open bite. Counterclockwise rotation of the mandible afforded significantly greater sagittal displacement at the B point (mean 17 mm) than at the first molar (mean 10 mm) and produced adequate degrees of projection of the lower face when accompanied by a modest sliding genioplasty (mean 6.9 mm). Total advancement at the pogonion was a mean of 25.2 mm. In addition, posterior facial height was preserved, and mandibular and occlusal planes were normalized to mean angles of 27 and 10 degrees, respectively. At follow-up, which ranged from 9 to 24 months with a mean of 14.1 months, the mean sagittal relapse at the B point was 1.9 mm. Although heretofore considered unstable and therefore not clinically accepted, maxillomandibular counterclockwise rotation to normalize the occlusal plane rotational deformity provides stable, aesthetically

  3. Orbital angular momentum of a high-order Bessel light beam

    International Nuclear Information System (INIS)

    Volke-Sepulveda, K; Garces-Chavez, V; Chavez-Cerda, S; Arlt, J; Dholakia, K

    2002-01-01

    The orbital angular momentum density of Bessel beams is calculated explicitly within a rigorous vectorial treatment. This allows us to investigate some aspects that have not been analysed previously, such as the angular momentum content of azimuthally and radially polarized beams. Furthermore, we demonstrate experimentally the mechanical transfer of orbital angular momentum to trapped particles in optical tweezers using a high-order Bessel beam. We set transparent particles of known dimensions into rotation, where the sense of rotation can be reversed by changing the sign of the singularity. Quantitative results are obtained for rotation rates. This paper's animations are available from the Multimedia Enhancements page

  4. Momentum and Angular Momentum Transfer in Oblique Impacts: Implications for Asteroid Rotations

    Science.gov (United States)

    Yanagisawa, Masahisa; Hasegawa, Sunao; Shirogane, Nobutoshi

    1996-09-01

    We conducted a series of high velocity oblique impact experiments (0.66-6.7 km/s) using polycarbonate (plastic) projectiles and targets made of mortar, aluminum alloy, and mild steel. We then calculated the efficiencies of momentum transfer for small cratering impacts. They are η = (M‧Vn‧)/(mvn) and ζ = (M‧Vt‧)/(mvt), wheremandvare the mass and velocity of a projectile, andM‧ andV‧ represent those of a postimpact target. Subscripts “n” and “t” denote the components normal and tangential to the target surface at the impact point, respectively. The main findings are: (1) η increases with increasing impact velocity; (2) η is larger for mortar than for ductile metallic targets; (3) ζ for mortar targets seems to increase with the impact velocity in the velocity range less than about 2 km/s and decrease with it in the higher velocity range; (4) ζ for the aluminum alloy targets correlates negatively with incident zenith angle of the projectile. In addition to these findings on the momentum transfer, we show theoretically that “ζL” can be expressed by η and ζ for small cratering impact. Here, ζLis the spin angular momentum that the target acquires at impact divided by the collisional angular momentum due to the projectile. This is an important parameter to study the collisional evolution of asteroid rotation. For a spherical target, ζLis shown to be well approximated by ζ.

  5. Optical angular momentum and atoms.

    Science.gov (United States)

    Franke-Arnold, Sonja

    2017-02-28

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

  6. Optical angular momentum and atoms

    Science.gov (United States)

    2017-01-01

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

  7. Total angular momentum from Dirac eigenspinors

    International Nuclear Information System (INIS)

    Szabados, Laszlo B

    2008-01-01

    The eigenvalue problem for Dirac operators, constructed from two connections on the spinor bundle over closed spacelike 2-surfaces, is investigated. A class of divergence-free vector fields, built from the eigenspinors, are found, which, for the lowest eigenvalue, reproduce the rotation Killing vectors of metric spheres, and provide rotation BMS vector fields at future null infinity. This makes it possible to introduce a well-defined, gauge invariant spatial angular momentum at null infinity, which reduces to the standard expression in stationary spacetimes. The general formula for the angular momentum flux carried away by the gravitational radiation is also derived

  8. Angular Momentum

    Science.gov (United States)

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

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

  9. Orbital angular momentum in phase space

    International Nuclear Information System (INIS)

    Rigas, I.; Sanchez-Soto, L.L.; Klimov, A.B.; Rehacek, J.; Hradil, Z.

    2011-01-01

    Research highlights: → We propose a comprehensive Weyl-Wigner formalism for the canonical pair angle-angular momentum. → We present a simple and useful toolkit for the practitioner. → We derive simple evolution equations in terms of a star product in the semiclassical limit. - Abstract: A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented. Special attention is paid to the problems linked to rotational periodicity and angular-momentum discreteness.

  10. The use of the T1 sagittal angle in predicting overall sagittal balance of the spine.

    Science.gov (United States)

    Knott, Patrick T; Mardjetko, Steven M; Techy, Fernando

    2010-11-01

    A balanced sagittal alignment of the spine has been shown to strongly correlate with less pain, less disability, and greater health status scores. To restore proper sagittal balance, one must assess the position of the occiput relative to the sacrum. The assessment of spinal balance preoperatively can be challenging, whereas predicting postoperative balance is even more difficult. This study was designed to evaluate and quantify multiple factors that influence sagittal balance. Retrospective analysis of existing spinal radiographs. A retrospective review of 52 adult spine patient records was performed. All patients had full-column digital radiographs that showed all the important skeletal landmarks necessary for accurate measurement. The average age of the patient was 53 years. Both genders were equally represented. The radiographs were measured using standard techniques to obtain the following parameters: scoliosis in the coronal plane; lordosis or kyphosis of the cervical, thoracic, and lumbar spine; the T1 sagittal angle (angle between a horizontal line and the superior end plate of T1); the angle of the dens in the sagittal plane; the angle of the dens in relation to the occiput; the sacral slope; the pelvic incidence; the femoral-sacral angle; and finally, the sagittal vertical axis (SVA) measured from both the dens of C2 and from C7. It was found that the SVA when measured from the dens was on average 16 mm farther forward than the SVA measured from C7 (p<.0001). The dens plumb line (SVA(dens)) was then used in the study. An analysis was done to examine the relationship between SVA(dens) and each of the other measurements. The T1 sagittal angle was found to have a moderate positive correlation (r=0.65) with SVA(dens), p<.0001, indicating that the amount of sagittal T1 tilt can be used as a good predictor of overall sagittal balance. When examining the other variables, it was found that cervical lordosis had a weak correlation (r=0.37) with SVA(dens) that was

  11. Variation in angular velocity and angular acceleration of a particle in rectilinear motion

    International Nuclear Information System (INIS)

    Mashood, K K; Singh, V A

    2012-01-01

    We discuss the angular velocity and angular acceleration associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a straight line. We present some details of our observations. A formal derivation of ω and α is presented which reveals ‘surprising’ and non-intuitive aspects, namely non-monotonic behaviour with an associated extremum. The special case of constant velocity is studied and we find that angular acceleration associated with it also has an extremum. We discuss a plausible source of difficulty. (paper)

  12. Macroscopic angular-momentum stages of Bose-Einstein condensates in toroidal traps

    International Nuclear Information System (INIS)

    Benakli, M.; Raghavan, S.; Smerzi, A.; Fantoni, S.; Shenoy, S.R.

    2001-03-01

    We study the stability of a rotating repulsive-atom Bose-Einstein condensate in a toroidal trap. The resulting macroscopic angular-momentum states with integer vorticity l spread radially, lowering rotational energies. These states are robust against vorticity-lowering decays, with estimated metastability barriers capable of sustaining large angular momenta (1 < or ∼ 10) for typical parameters. We identify the centrifugally squashed l-dependent density profile as a possible signature of condensate rotation and superfluidity. (author)

  13. Operator theory of angular momentum nad orientational auto-correlation functions

    International Nuclear Information System (INIS)

    Evans, M.W.

    1982-01-01

    The rigorous relation between the orientational auto-correlation function and the angular momentum autocorrelation function is described in two cases of interest. First when description of the complete zero THz- spectrum is required from the Mori continued fraction expansion for the angular momentum autocorrelation function and second when rotation/translation effects are important. The Mori-Evans theory of 1976, relying on the simple Shimizu relation is found to be essentially unaffected by the higher order corrections recently worked out by Ford and co-workers in the Markov limit. The mutual interaction of rotation and translation is important in determining the details of both the orientational and angular momentum auto-correlation function's (a.c.f.'s) in the presence of sample anisotropy or a symmetry breaking field. In this case it is essential to regard the angular momentum a.c.f. as non-Markovian and methods are developed to relate this to the orientational a.c.f. in the presence of rotation/translation coupling. (author)

  14. Angular Accelerating White Light

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2015-08-01

    Full Text Available wavelength dependence. By digitally simulating free-space propagation on the SLM, The authors compare the effects of real and digital propagation on the angular rotation rates of the resulting optical fields for various wavelengths. The development...

  15. Photofragment angular momentum distribution beyond the axial recoil approximation: Predissociation

    International Nuclear Information System (INIS)

    Kuznetsov, Vladislav V.; Vasyutinskii, Oleg S.

    2007-01-01

    We present the quantum mechanical expressions for the angular momentum distribution of the photofragments produced in slow predissociation. The paper is based on our recent theoretical treatment [J. Chem. Phys. 123, 034307 (2005)] of the recoil angle dependence of the photofragment multipole moments which explicitly treat the role of molecular axis rotation on the electronic angular momentum polarization of the fragments. The electronic wave function of the molecule was used in the adiabatic body frame representation. The rigorous expressions for the fragment state multipoles which have been explicitly derived from the scattering wave function formalism have been used for the case of slow predissociation where a molecule lives in the excited quasibound state much longer than a rotation period. Possible radial nonadiabatic interactions were taken into consideration. The optical excitation of a single rotational branch and the broadband incoherent excitation of all possible rotational branches have been analyzed in detail. The angular momentum polarization of the photofragments has been treated in the high-J limit. The polarization of the photofragment angular momenta predicted by the theory depends on photodissociation mechanism and can in many cases be significant

  16. Up-down symmetry of the turbulent transport of toroidal angular momentum in tokamaks

    International Nuclear Information System (INIS)

    Parra, Felix I.; Barnes, Michael; Peeters, Arthur G.

    2011-01-01

    Two symmetries of the local nonlinear δf gyrokinetic system of equations in tokamaks in the high flow regime are presented. The turbulent transport of toroidal angular momentum changes sign under an up-down reflection of the tokamak and a sign change of both the rotation and the rotation shear. Thus, the turbulent transport of toroidal angular momentum must vanish for up-down symmetric tokamaks in the absence of both rotation and rotation shear. This has important implications for the modeling of spontaneous rotation.

  17. Additional measurements of pre-main-sequence stellar rotation

    International Nuclear Information System (INIS)

    Hartmann, L.; Stauffer, J.R.

    1989-01-01

    New rotational-velocity measurements for pre-main-sequence stars in the Taurus-Auriga molecular cloud are reported. Rotational velocities or upper limits of 10 km/s are now available for 90 percent of the T Tauri stars with V less than 14.7 in the catalog of Cohen and Kuhi. Measurements of 'continuum emission' stars, thought to be accreting high-angular-momentum material from a circumstellar disk, show that these objects are not especially rapid rotators. The results confirm earlier findings that angular-momentum loss proceeds very efficiently in the earliest stages of star formation, and suggest that stars older than about one million yr contract to the main sequence at nearly constant angular momentum. The slow rotation of T Tauri stars probably requires substantial angular-momentum loss via a magnetically coupled wind. 35 references

  18. Earth Rotation and Coupling to Changes in Atmospheric Angular Momentum

    Science.gov (United States)

    Rosen, Richard D.; Frey, H. (Technical Monitor)

    2000-01-01

    The research supported under the contract dealt primarily with: (a) the mechanisms responsible for the exchange of angular momentum between the solid Earth and atmosphere; (b) the quality of the data sets used to estimate atmospheric angular momentum; and (c) the ability of these data and of global climate models to detect low-frequency signals in the momentum and, hence, circulation of the atmosphere. Three scientific papers reporting on the results of this research were produced during the course of the contract. These papers identified the particular torques responsible for the peak in atmospheric angular momentum and length-of-day during the 1982-93 El Nino event, and, more generally, the relative roles of torques over land and ocean in explaining the broad spectrum of variability in the length-of-day. In addition, a tendency for interannual variability in atmospheric angular momentum to increase during the last several decades of the 20th century was found in both observations and a global climate model experiment.

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

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-09-01

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

  20. Theory of generation of angular momentum of phonons by heat current and its conversion to spins

    Science.gov (United States)

    Hamada, Masato; Murakami, Shuichi

    Spin-rotation coupling in crystals will enable us to convert between spin current and mechanical rotations, as has been studied in surface acoustic waves, in liquid metals, and in carbon nanotubes. In this presentation we focus on angular momentum of phonons. In nonmagnetic crystals without inversion symmetry, we theoretically demonstrate that phonon modes generally have angular momenta depending on their wave vectors. In equilibrium the sum of the angular momenta is zero. On the other hand, if a heat current flows in the crystal, nonequilibrium phonon distribution leads to nonzero total angular momentum of phonons. It can be observed as a rotation of crystal itself, and as a spin current induced by these phonons via the spin-rotation coupling.

  1. Angular distributions in quasi-fission reactions

    International Nuclear Information System (INIS)

    Luetzenkirchen, K.; Kratz, J.V.; Lucas, R.; Poitou, J.; Gregoire, C.; Wirth, G.; Bruechle, W.; Suemmerer, K.

    1985-10-01

    Angular distributions for fission-like fragments were measured in the systems 50 Ti, 56 Fe + 208 Pb by applying an off-line KX-ray activation technique. The distributions d 2 sigma/dTHETAdZ exhibit forward-backward asymmetries that are strongly Z-dependent. They result from a process (quasi-fission) which yields nearly symmetric masses in times comparable to the rotational period of the composite system. A method for obtaining the variance of the tilting angular momentum, K 0 2 , from these skewed, differential angular distributions is described. The results indicate that the tilting mode is not fully excited in quasi-fission reactions. The results are compared to the sum of the variances of all statistical spin components, measured via γ-multiplicities. Integration of the angular distributions d 2 sigma/dTHETAdZ over all values of Z yields integral angular distributions dsigma/dTHETA and dsigma/dΩ symmetric around 90 0 . The associated unusually large anisotropies do not at all provide an adequate basis for tests or modifications of the transition state theory. A deconvolution of d 2 sigma/dTHETAdZ is performed with gaussian distributions depending on rotational angles ΔTHETA extending over a range of up to 540 0 . From the mean values a time scale for the evolution of K 0 is calculated. (orig.)

  2. Sagittal crest formation in great apes and gibbons.

    Science.gov (United States)

    Balolia, Katharine L; Soligo, Christophe; Wood, Bernard

    2017-06-01

    The frequency of sagittal crest expression and patterns of sagittal crest growth and development have been documented in hominoids, including some extinct hominin taxa, and the more frequent expression of the sagittal crest in males has been traditionally linked with the need for larger-bodied individuals to have enough attachment area for the temporalis muscle. In the present study, we investigate sagittal cresting in a dentally mature sample of four hominoid taxa (Pan troglodytes schweinfurthii, Gorilla gorilla gorilla, Pongo pygmaeus pygmaeus and Hylobates lar). We investigate whether sagittal crest size increases with age beyond dental maturity in males and females of G. g. gorilla and Po. pyg. pygmaeus, and whether these taxa show sex differences in the timing of sagittal crest development. We evaluate the hypothesis that the larger sagittal crest of males may not be solely due to the requirement for a larger surface area than the un-crested cranial vault can provide for the attachment of the temporalis muscle, and present data on sex differences in temporalis muscle attachment area and sagittal crest size relative to cranial size. Gorilla g. gorilla and Po. pyg. pygmaeus males show significant relationships between tooth wear rank and sagittal crest size, and they show sagittal crest size differences between age groups that are not found in females. The sagittal crest emerges in early adulthood in the majority of G. g. gorilla males, whereas the percentage of G. g. gorilla females possessing a sagittal crest increases more gradually. Pongo pyg. pygmaeus males experience a three-fold increase in the number of specimens exhibiting a sagittal crest in mid-adulthood, consistent with a secondary growth spurt. Gorilla g. gorilla and Po. pyg. pygmaeus show significant sex differences in the size of the temporalis muscle attachment area, relative to cranial size, with males of both taxa showing positive allometry not shown in females. Gorilla g

  3. Angular Positioning Sensor for Space Mechanisms

    Science.gov (United States)

    Steiner, Nicolas; Chapuis, Dominique

    2013-09-01

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

  4. Classical theory of rotational rainbow scattering from uncorrugated surfaces

    International Nuclear Information System (INIS)

    Khodorkovsky, Yuri; Averbukh, Ilya Sh; Pollak, Eli

    2010-01-01

    A classical perturbation theory is developed to study rotational rainbow scattering of molecules from uncorrugated frozen surfaces. Considering the interaction of the rigid rotor with the translational motion towards the surface to be weak allows for a perturbative treatment, in which the known zeroth order motion is that of a freely rotating molecule hitting a surface. Using perturbation theory leads to explicit expressions for the angular momentum deflection function with respect to the initial orientational angle of the rotor that are valid for any magnitude of the initial angular momentum. The rotational rainbows appear as peaks both in the final angular momentum and rotational energy distributions, as well as peaks in the angular distribution, although the surface is assumed to be uncorrugated. The derived analytic expressions are compared with numerical simulation data. Even when the rotational motion is significantly coupled to the translational motion, the predictions of the perturbative treatment remain qualitatively correct.

  5. Large rotating field entropy change in ErFeO3 single crystal with angular distribution contribution

    Science.gov (United States)

    Huang, Ruoxiang; Cao, Shixun; Ren, Wei; Zhan, Sheng; Kang, Baojuan; Zhang, Jincang

    2013-10-01

    We report the rotating field entropy of ErFeO3 single-crystal in a temperature range of 3-40 K. The giant magnetic entropy change, ΔSM = -20.7 J/(kg K), and the refrigerant capacity, RC = 273.5 J/kg, are observed near T =6 K. The anisotropic constants at 6 K, K1 = 1.24× 103 J/kg, K2 = 0.74 × 103 J/kg, in the bc plane are obtained. By considering the magnetocrystalline anisotropy and Fermi-Dirac angular distribution along the orientation of spontaneous magnetization, the experimental results can be well simulated. Our present work demonstrates that ErFeO3 crystal may find practical use for low temperature anisotropic magnetic refrigeration.

  6. Postural Consequences of Cervical Sagittal Imbalance: A Novel Laboratory Model.

    Science.gov (United States)

    Patwardhan, Avinash G; Havey, Robert M; Khayatzadeh, Saeed; Muriuki, Muturi G; Voronov, Leonard I; Carandang, Gerard; Nguyen, Ngoc-Lam; Ghanayem, Alexander J; Schuit, Dale; Patel, Alpesh A; Smith, Zachary A; Sears, William

    2015-06-01

    A biomechanical study using human spine specimens. To study postural compensations in lordosis angles that are necessary to maintain horizontal gaze in the presence of forward head posture and increasing T1 sagittal tilt. Forward head posture relative to the shoulders, assessed radiographically using the horizontal offset distance between the C2 and C7 vertebral bodies (C2-C7 [sagittal vertical alignment] SVA), is a measure of global cervical imbalance. This may result from kyphotic alignment of cervical segments, muscle imbalance, as well as malalignment of thoracolumbar spine. Ten cadaveric cervical spines (occiput-T1) were tested. The T1 vertebra was anchored to a tilting and translating base. The occiput was free to move vertically but its angular orientation was constrained to ensure horizontal gaze regardless of sagittal imbalance. A 5-kg mass was attached to the occiput to mimic head weight. Forward head posture magnitude and T1 tilt were varied and motions of individual vertebrae were measured to calculate C2-C7 SVA and lordosis across C0-C2 and C2-C7. Increasing C2-C7 SVA caused flexion of lower cervical (C2-C7) segments and hyperextension of suboccipital (C0-C1-C2) segments to maintain horizontal gaze. Increasing kyphotic T1 tilt primarily increased lordosis across the C2-C7 segments. Regression models were developed to predict the compensatory C0-C2 and C2-C7 angulation needed to maintain horizontal gaze given values of C2-C7 SVA and T1 tilt. This study established predictive relationships between radiographical measures of forward head posture, T1 tilt, and postural compensations in the cervical lordosis angles needed to maintain horizontal gaze. The laboratory model predicted that normalization of C2-C7 SVA will reduce suboccipital (C0-C2) hyperextension, whereas T1 tilt reduction will reduce the hyperextension in the C2-C7 segments. The predictive relationships may help in planning corrective strategy in patients experiencing neck pain, which may be

  7. Mach's principle and rotating universes

    International Nuclear Information System (INIS)

    King, D.H.

    1990-01-01

    It is shown that the Bianchi 9 model universe satisfies the Mach principle. These closed rotating universes were previously thought to be counter-examples to the principle. The Mach principle is satisfied because the angular momentum of the rotating matter is compensated by the effective angular momentum of gravitational waves. A new formulation of the Mach principle is given that is based on the field theory interpretation of general relativity. Every closed universe with 3-sphere topology is shown to satisfy this formulation of the Mach principle. It is shown that the total angular momentum of the matter and gravitational waves in a closed 3-sphere topology universe is zero

  8. Close binary evolution. II. Impact of tides, wind magnetic braking, and internal angular momentum transport

    Science.gov (United States)

    Song, H. F.; Meynet, G.; Maeder, A.; Ekström, S.; Eggenberger, P.; Georgy, C.; Qin, Y.; Fragos, T.; Soerensen, M.; Barblan, F.; Wade, G. A.

    2018-01-01

    Context. Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-initial-mass stars. In a close binary system, the effect of wind magnetic braking also interacts with the influence of tides, resulting in a complex evolution of rotation. Aims: We study the interactions between the process of wind magnetic braking and tides in close binary systems. Methods: We discuss the evolution of a 10 M⊙ star in a close binary system with a 7 M⊙ companion using the Geneva stellar evolution code. The initial orbital period is 1.2 days. The 10 M⊙ star has a surface magnetic field of 1 kG. Various initial rotations are considered. We use two different approaches for the internal angular momentum transport. In one of them, angular momentum is transported by shear and meridional currents. In the other, a strong internal magnetic field imposes nearly perfect solid-body rotation. The evolution of the primary is computed until the first mass-transfer episode occurs. The cases of different values for the magnetic fields and for various orbital periods and mass ratios are briefly discussed. Results: We show that, independently of the initial rotation rate of the primary and the efficiency of the internal angular momentum transport, the surface rotation of the primary will converge, in a time that is short with respect to the main-sequence lifetime, towards a slowly evolving velocity that is different from the synchronization velocity. This "equilibrium angular velocity" is always inferior to the angular orbital velocity. In a given close binary system at this equilibrium stage, the difference between the spin and the orbital angular velocities becomes larger when the mass losses and/or the surface magnetic field increase. The

  9. Comparison of prostate contours between conventional stepping transverse imaging and Twister-based sagittal imaging in permanent interstitial prostate brachytherapy.

    Science.gov (United States)

    Kawakami, Shogo; Ishiyama, Hiromichi; Satoh, Takefumi; Tsumura, Hideyasu; Sekiguchi, Akane; Takenaka, Kouji; Tabata, Ken-Ichi; Iwamura, Masatsugu; Hayakawa, Kazushige

    2017-08-01

    To compare prostate contours on conventional stepping transverse image acquisitions with those on twister-based sagittal image acquisitions. Twenty prostate cancer patients who were planned to have permanent interstitial prostate brachytherapy were prospectively accrued. A transrectal ultrasonography probe was inserted, with the patient in lithotomy position. Transverse images were obtained with stepping movement of the transverse transducer. In the same patient, sagittal images were also obtained through rotation of the sagittal transducer using the "Twister" mode. The differences of prostate size among the two types of image acquisitions were compared. The relationships among the difference of the two types of image acquisitions, dose-volume histogram (DVH) parameters on the post-implant computed tomography (CT) analysis, as well as other factors were analyzed. The sagittal image acquisitions showed a larger prostate size compared to the transverse image acquisitions especially in the anterior-posterior (AP) direction ( p transverse image acquisitions was correlated to DVH parameters such as D 90 ( R = 0.518, p = 0.019), and V 100 ( R = 0.598, p = 0.005). There were small but significant differences in the prostate contours between the transverse and the sagittal planning image acquisitions. Furthermore, our study suggested that the differences between the two types of image acquisitions might correlated to dosimetric results on CT analysis.

  10. Measuring the Angular Velocity of a Propeller with Video Camera Using Electronic Rolling Shutter

    Directory of Open Access Journals (Sweden)

    Yipeng Zhao

    2018-01-01

    Full Text Available Noncontact measurement for rotational motion has advantages over the traditional method which measures rotational motion by means of installing some devices on the object, such as a rotary encoder. Cameras can be employed as remote monitoring or inspecting sensors to measure the angular velocity of a propeller because of their commonplace availability, simplicity, and potentially low cost. A defect of the measurement with cameras is to process the massive data generated by cameras. In order to reduce the collected data from the camera, a camera using ERS (electronic rolling shutter is applied to measure angular velocities which are higher than the speed of the camera. The effect of rolling shutter can induce geometric distortion in the image, when the propeller rotates during capturing an image. In order to reveal the relationship between the angular velocity and the image distortion, a rotation model has been established. The proposed method was applied to measure the angular velocities of the two-blade propeller and the multiblade propeller. The experimental results showed that this method could detect the angular velocities which were higher than the camera speed, and the accuracy was acceptable.

  11. A neural circuit for angular velocity computation

    Directory of Open Access Journals (Sweden)

    Samuel B Snider

    2010-12-01

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

  12. Accuracy and repeatability of quantitative fluoroscopy for the measurement of sagittal plane translation and finite centre of rotation in the lumbar spine.

    Science.gov (United States)

    Breen, Alexander; Breen, Alan

    2016-07-01

    Quantitative fluoroscopy (QF) was developed to measure intervertebral mechanics in vivo and has been found to have high repeatability and accuracy for the measurement of intervertebral rotations. However, sagittal plane translation and finite centre of rotation (FCR) are potential measures of stability but have not yet been fully validated for current QF. This study investigated the repeatability and accuracy of QF for measuring these variables. Repeatability was assessed from L2-S1 in 20 human volunteers. Accuracy was investigated using 10 consecutive measurements from each of two pairs of linked and instrumented dry human vertebrae as reference; one which tilted without translation and one which translated without tilt. The results found intra- and inter-observer repeatability for translation to be 1.1mm or less (SEM) with fair to substantial reliability (ICC 0.533-0.998). Intra-observer repeatability of FCR location for inter-vertebral rotations of 5° and above ranged from 1.5mm to 1.8mm (SEM) with moderate to substantial reliability (ICC 0.626-0.988). Inter-observer repeatability for FCR ranged from 1.2mm to 5.7mm, also with moderate to substantial reliability (ICC 0.621-0.878). Reliability was substantial (ICC>0.81) for 10/16 measures for translation and 5/8 for FCR location. Accuracy for translation was 0.1mm (fixed centre) and 2.2mm (moveable centre), with an FCR error of 0.3mm(x) and 0.4mm(y) (fixed centre). This technology was found to have a high level of accuracy and with a few exceptions, moderate to substantial repeatability for the measurement of translation and FCR from fluoroscopic motion sequences. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  13. Sagittal crest formation in great apes and gibbons

    OpenAIRE

    Balolia, K. L.; Soligo, C.; Wood, B.

    2017-01-01

    The frequency of sagittal crest expression and patterns of sagittal crest growth and development have been documented in hominoids, including some extinct hominin taxa, and the more frequent expression of the sagittal crest in males has been traditionally linked with the need for larger-bodied individuals to have enough attachment area for the temporalis muscle. In the present study, we investigate sagittal cresting in a dentally mature sample of four hominoid taxa (Pan troglodytes schweinfur...

  14. Motions on a rotating planet

    Science.gov (United States)

    Schröer, H.

    In chapter 1 we want to describe the motion of a falling body on a rotating planet. The planet rotates with an arbitrary changable angular velocity and has a translational acceleration. We obtain 3 differential equations. For the general gravitational field an exact solution is possible, when the differential equation system is explicit solvable. Then we consider the case, if the angular velocity and the translational acceleration is constant. With a special transformation we get 3 partial differential equations of first order. Instead of a planet sphere we can choose a general body of rotation. Even general bodies are possible. Chapter 2 contains the motion in a local coordinate system on planet's surface. We have an inhomogeneous linear differential equation of first order. If the angular velocity is constant, we get a system with constant coefficients. There is an english and a german edition.

  15. Analysis of sagittal spinopelvic parameters in achondroplasia.

    Science.gov (United States)

    Hong, Jae-Young; Suh, Seung-Woo; Modi, Hitesh N; Park, Jong-Woong; Park, Jung-Ho

    2011-08-15

    Prospective radiological analysis of patients with achondroplasia. To analyze sagittal spinal alignment and pelvic orientation in achondroplasia patients. Knowledge of sagittal spinopelvic parameters is important for the treatment of achondroplasia, because they differ from those of the normal population and can induce pain. The study and control groups were composed of 32 achondroplasia patients and 24 healthy volunteers, respectively. All underwent lateral radiography of the whole spine including hip joints. The radiographic parameters examined were sacral slope (SS), pelvic tilt, pelvic incidence (PI), S1 overhang, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis (LL1, LL2), and sagittal balance. Statistical analysis was performed to identify significant differences between the two groups. In addition, correlations between parameters and symptoms were sought. Sagittal spinopelvic parameters, namely, pelvic tilt, pelvic incidence, S1 overhang, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis 1 and sagittal balance were found to be significantly different in the patient and control groups (P achondroplasia patients and normal healthy controls. The present study shows that sagittal spinal and pelvic parameters can assist the treatment of spinal disorders in achondroplasia patients.

  16. Revolution evolution: tracing angular momentum during star and planetary system formation

    Science.gov (United States)

    Davies, Claire Louise

    2015-04-01

    Stars form via the gravitational collapse of molecular clouds during which time the protostellar object contracts by over seven orders of magnitude. If all the angular momentum present in the natal cloud was conserved during collapse, stars would approach rotational velocities rapid enough to tear themselves apart within just a few Myr. In contrast to this, observations of pre-main sequence rotation rates are relatively slow (∼ 1 - 15 days) indicating that significant quantities of angular momentum must be removed from the star. I use observations of fully convective pre-main sequence stars in two well-studied, nearby regions of star formation (namely the Orion Nebula Cluster and Taurus-Auriga) to determine the removal rate of stellar angular momentum. I find the accretion disc-hosting stars to be rotating at a slower rate and contain less specific angular momentum than the disc-less stars. I interpret this as indicating a period of accretion disc-regulated angular momentum evolution followed by near-constant rotational evolution following disc dispersal. Furthermore, assuming that the age spread inferred from the Hertzsprung-Russell diagram constructed for the star forming region is real, I find that the removal rate of angular momentum during the accretion-disc hosting phase to be more rapid than that expected from simple disc-locking theory whereby contraction occurs at a fixed rotation period. This indicates a more efficient process of angular momentum removal must operate, most likely in the form of an accretion-driven stellar wind or outflow emanating from the star-disc interaction. The initial circumstellar envelope that surrounds a protostellar object during the earliest stages of star formation is rotationally flattened into a disc as the star contracts. An effective viscosity, present within the disc, enables the disc to evolve: mass accretes inwards through the disc and onto the star while momentum migrates outwards, forcing the outer regions of the

  17. Angular momentum transport and dynamo action in the sun - Implications of recent oscillation measurements

    International Nuclear Information System (INIS)

    Gilman, P. A.; Morrow, C. A.; Deluca, E. E.

    1989-01-01

    The implications of a newly proposed picture of the sun's internal rotation (Brown et al., 1989; Morrow, 1988) for the distribution and transport of angular momentum and for the solar dynamo are considered. The new results, derived from an analysis of solar acoustic oscillations, affect understanding of how momentum is cycled in the sun and provide clues as to how and where the solar dynamo is driven. The data imply that the only significant radial gradient of angular velocity exists in a transitional region between the bottom of the convection zone, which is rotating like the solar surface, and the top of the deep interior, which is rotating rigidly at a rate intermediate between the equatorial and polar rates at the surface. Thus the radial gradient must change sign at the latitude where the angular velocity of the surface matches that of the interior. These inferences suggest that the cycle of angular momentum that produces the observed latitudinal differential rotation in the convection zone may be coupled to layers of the interior beneath the convection zone. 35 refs

  18. Angular momentum in general relativity

    International Nuclear Information System (INIS)

    Prior, C.R.

    1977-01-01

    The definition of angular momentum proposed in part I of this series (Prior. Proc. R. Soc. Lond.; A354:379 (1977)) is investigated when applied to rotating black holes. It is shown how to use the formula to evaluate the angular momentum of a stationary black hole. This acts as a description of a background space on which the effect of first matter and then gravitational perturbations is considered. The latter are of most interest and the rate of change of angular momentum, dJ/dt, is found as an expression in the shear induced in the event horizon by the perturbation and in its time integral. Teukolsky's solutions (Astrophys. J.; 185:635 (1973)) for the perturbed component of the Weyl tensor are then used to find this shear and hence to give an exact answer for dJ/dt. One of the implications of the result is a direct verification of Bekenstein's formula (Phys. Rev.; 7D:949 (1973)) relating in a simple way the rate of change of angular momentum to the rate of change of mass caused by a plane wave. A more general expression is also given for dM/dt. Considering only stationary perturbations, it is shown how to generalize the definition of angular momentum so as to include information about its direction as well. Three problems are particularly discussed - a single moon, two or more moons and a ring of matter causing the perturbation - since they provide illustrations of all the main features of the black hole's behaviour. In every case it is found that the black hole realigns its axis of rotation so that the final configuration is axisymmetric if possible; otherwise is slows down completely to reach a static state. (author)

  19. An investigation of head movement with a view to minimising motion artefact during SPECT and PET imaging of the brain

    International Nuclear Information System (INIS)

    Patterson, H.; Clarke, G.H.; Guy, R.; McKay, W.J.

    1998-01-01

    Full text: Motion artefact has long been recognised as a major cause of image degradation. Single Photon Emission Computerised Tomography (SPECT) and Positron Emission Tomography (PET) of the brain are playing an important role in the diagnosis and management of several neurological disorders. If these imaging modalities are to contribute fully to medical imaging it is essential that the improved spatial resolution of these systems is not compromised by patient movement. Thirty volunteer subjects have been examined using a simple video technique and the video images were used to classify and measure head movements which may occur during brain imaging. All subjects demonstrated angular movement within the transverse plane or rotation of the head. Angular movement within the sagittal plane or flexion/extension of the neck occurred in 69% of subjects and 72% of subjects exhibited translational movement of the sagittal plane. There was no movement of the coronal plane; nor was there any translational movement of the sagittal plane. These results suggest that when positioning the patient's head for brain imaging a system of head restraint which minimises rotation of the head should be used if image quality is to be maintained

  20. Nuclear collective rotation in the SU3 model, 2

    International Nuclear Information System (INIS)

    Kinouchi, Shin-ichi; Kishimoto, Teruo; Kammuri, Tetsuo.

    1989-05-01

    The collective rotation of a nuclear system with the SU 3 Hamiltonian is described by the quantal dynamical nuclear field theory. An angular frequency in the Coriolis interaction of the driving Hamiltonian is replaced by a total angular momentum operator divided by the corresponding moment of inertia. We consider here the low spin states for a triaxial intrinsic configuration. The rotational effect is taken into account by using the effective quadrupole and angular momentum operators, whose expressions are different depending on whether they refer to the laboratory frame or the body-fixed one. Effective forms of the total Hamiltonian and the particle angular momentum are compared with the exact SU 3 energy and the rotor's angular momentum, respectively. In order to dissolve the disagreement for the effective operators, the perturbing interaction should be supplemented by a residual part of the quadrupole-quadrupole interaction, which restores the rotational invariance of the intrinsic Hamiltonian. (author)

  1. Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry.

    Science.gov (United States)

    Vadilonga, Simone; Zizak, Ivo; Roshchupkin, Dmitry; Evgenii, Emelin; Petsiuk, Andrei; Leitenberger, Wolfram; Erko, Alexei

    2017-04-01

    X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La 3 Ga 5 SiO 14 ) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space-time modulation of an X-ray beam.

  2. Angular-momentum-assisted dissociation of CO in strong optical fields

    Science.gov (United States)

    Mullin, Amy; Ogden, Hannah; Murray, Matthew; Liu, Qingnan; Toro, Carlos

    2017-04-01

    Filaments are produced in CO gas by intense, chirped laser pulses. Visible emission from C2 is observed as a result of chemical reactions of highly excited CO. At laser intensities greater than 1014 W cm-2, the C2 emission shows a strong dependence on laser polarization. Oppositely chirped pulses of light with ω0 = 800 nm are recombined spatially and temporally to generate angularly accelerating electric fields (up to 30 THz) that either have an instantaneous linear polarization or act as a dynamic polarization grating that oscillates among linear and circular polarizations. The angularly accelerating linear polarization corresponds to an optical centrifuge that concurrently drives molecules into high rotational states (with J 50) and induces strong-field dissociation. Higher order excitation is observed for the time-varying laser polarization configuration that does not induce rotational excitation. The results indicate that the presence of rotational angular momentum lowers the threshold for CO dissociation in strong optical fields by coupling nuclear and electronic degrees of freedom. Support from NSF CHE-1058721 and the University of Maryland.

  3. Angular momentum conservation for uniformly expanding flows

    International Nuclear Information System (INIS)

    Hayward, Sean A

    2007-01-01

    Angular momentum has recently been defined as a surface integral involving an axial vector and a twist 1-form, which measures the twisting around the spacetime due to a rotating mass. The axial vector is chosen to be a transverse, divergence-free, coordinate vector, which is compatible with any initial choice of axis and integral curves. Then a conservation equation expresses the rate of the change of angular momentum along a uniformly expanding flow as a surface integral of angular momentum densities, with the same form as the standard equation for an axial Killing vector, apart from the inclusion of an effective energy tensor for gravitational radiation

  4. Prenatal MR imaging of Dandy-Walker complex: Midline sagittal area analysis

    International Nuclear Information System (INIS)

    Wong, Alex M.; Bilaniuk, Larissa T.; Zimmerman, Robert A.; Liu, P.L.

    2012-01-01

    Objective: To measure the mid-sagittal areas of vermis (VA) and of posterior fossa (PFA) and determine their differences among fetuses with various Dandy-Walker (DW) entities and control subjects. Methods: We reviewed data in 25 fetal patients with a MR diagnosis of DW complex including hypoplastic vermis (HV), HV with rotation (HVR), and mega cistern magna (MCM), and in 85 fetal controls with normal CNS. PFA and VA of each subject were manually traced on mid-sagittal MR images. Regarding each of VA and PFA, after age correction, we determined statistically significant differences among HVR, HV, MCM, and control groups. Results: The mean VA residue of MCM was greater than that of the control, which was in turn greater than those of HVR and HV. The mean PF residue of the control was smaller than all other groups. Conclusion: Fetuses with HVR or HV had smaller VA than fetuses with MCM or control subjects. Fetuses with MCM, HVR, or HV had larger PFA than control subjects. These results may be an early step leading to better understanding of the confusion about the PF anomalies in future.

  5. Ocean angular momentum signals in a climate model and implications for Earth rotation

    Science.gov (United States)

    Ponte, R. M.; Rajamony, J.; Gregory, J. M.

    2002-03-01

    Estimates of ocean angular momentum (OAM) provide an integrated measure of variability in ocean circulation and mass fields and can be directly related to observed changes in Earth rotation. We use output from a climate model to calculate 240 years of 3-monthly OAM values (two equatorial terms L1 and L2, related to polar motion or wobble, and axial term L3, related to length of day variations) representing the period 1860-2100. Control and forced runs permit the study of the effects of natural and anthropogenically forced climate variability on OAM. All OAM components exhibit a clear annual cycle, with large decadal modulations in amplitude, and also longer period fluctuations, all associated with natural climate variability in the model. Anthropogenically induced signals, inferred from the differences between forced and control runs, include an upward trend in L3, related to inhomogeneous ocean warming and increases in the transport of the Antarctic Circumpolar Current, and a significantly weaker seasonal cycle in L2 in the second half of the record, related primarily to changes in seasonal bottom pressure variability in the Southern Ocean and North Pacific. Variability in mass fields is in general more important to OAM signals than changes in circulation at the seasonal and longer periods analyzed. Relation of OAM signals to changes in surface atmospheric forcing are discussed. The important role of the oceans as an excitation source for the annual, Chandler and Markowitz wobbles, is confirmed. Natural climate variability in OAM and related excitation is likely to measurably affect the Earth rotation, but anthropogenically induced effects are comparatively weak.

  6. A new picture for the internal rotation of the sun

    International Nuclear Information System (INIS)

    Morrow, C.A.

    1988-01-01

    This thesis describes a helioseismic quest to determine the angular velocity inside the Sun as a function of depth and latitude. The author analyzes rotational frequency splittings extracted from 15 days of full-disk observations of the solar acoustic oscillations (1 = 15-99) obtained with the Fourier Tachometer (a Doppler analyzing instrument design by Tim Brown). She has compared the observed frequency splittings to those generated by several different physically-motivated models for the solar internal angular velocity. She also introduces convenient preliminary analysis techniques, which require no formal computations and which guide the choices of rotation models. He analysis suggests that the differential rotation in latitude observed at the solar surface pervades the convection zone and perhaps even deeper layers. Thus, the convection zone appears to contain little or no radial gradient of angular velocity. The analysis further indicates that the angular velocity of the outer portion of the radiative interior is constant, or nearly so, at a value that is intermediate between the relatively fast equatorial rate and the slower polar rate of the surface profile. This new picture of the Sun's internal rotation implies that a significant radial gradient exists only in a transitional layer between the convection zone and the radiative interior. This model has intriguing implications for the solar dynamo, for the current distribution and transport of angular momentum, and for the current distribution and transport of angular momentum, and for the rotational and evolutionary history of the Sun

  7. Association of baseline knee sagittal dynamic joint stiffness during gait and 2-year patellofemoral cartilage damage worsening in knee osteoarthritis.

    Science.gov (United States)

    Chang, A H; Chmiel, J S; Almagor, O; Guermazi, A; Prasad, P V; Moisio, K C; Belisle, L; Zhang, Y; Hayes, K; Sharma, L

    2017-02-01

    Knee sagittal dynamic joint stiffness (DJS) describes the biomechanical interaction between change in external knee flexion moment and flexion angular excursion during gait. In theory, greater DJS may particularly stress the patellofemoral (PF) compartment and thereby contribute to PF osteoarthritis (OA) worsening. We hypothesized that greater baseline knee sagittal DJS is associated with PF cartilage damage worsening 2 years later. Participants all had OA in at least one knee. Knee kinematics and kinetics during gait were recorded using motion capture systems and force plates. Knee sagittal DJS was computed as the slope of the linear regression line for knee flexion moments vs angles during the loading response phase. Knee magnetic resonance imaging (MRI) scans were obtained at baseline and 2 years later. We assessed the association between baseline DJS and baseline-to-2-year PF cartilage damage worsening using logistic regression with generalized estimating equations (GEE). Our sample had 391 knees (204 persons): mean age 64.2 years (SD 10.0); body mass index (BMI) 28.4 kg/m 2 (5.7); 76.5% women. Baseline knee sagittal DJS was associated with baseline-to-2-year cartilage damage worsening in the lateral (OR = 5.35, 95% CI: 2.37-12.05) and any PF (OR = 2.99, 95% CI: 1.27-7.04) compartment. Individual components of baseline DJS (i.e., change in knee moment or angle) were not associated with subsequent PF disease worsening. Capturing the concomitant effect of knee kinetics and kinematics during gait, knee sagittal DJS is a potentially modifiable risk factor for PF disease worsening. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  8. Rotational velocities of low-mass stars

    International Nuclear Information System (INIS)

    Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1986-01-01

    The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

  9. Gravitomagnetism and angular momenta of black-holes

    OpenAIRE

    Marcelo Samuel Berman

    2007-01-01

    We review the energy contents formulae of Kerr-Newman black-holes, where gravitomagnetic energy term comes into play (Berman 2004, 2006a,b). Then, we obtain the angular momenta formulae, which include the gravitomagnetic effect. Three theorems can be enunciated: (1) No black-hole has its energy confined to its interior; (2) Rotating black-holes do not have confined angular momenta; (3) The energy density of a black-hole is not confined to its interior. The difference between our calculation a...

  10. Angular momentum of dwarf galaxies

    Science.gov (United States)

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

    2018-05-01

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

  11. A Simple and Efficient Numerical Method for Computing the Dynamics of Rotating Bose--Einstein Condensates via Rotating Lagrangian Coordinates

    KAUST Repository

    Bao, Weizhu

    2013-01-01

    We propose a simple, efficient, and accurate numerical method for simulating the dynamics of rotating Bose-Einstein condensates (BECs) in a rotational frame with or without longrange dipole-dipole interaction (DDI). We begin with the three-dimensional (3D) Gross-Pitaevskii equation (GPE) with an angular momentum rotation term and/or long-range DDI, state the twodimensional (2D) GPE obtained from the 3D GPE via dimension reduction under anisotropic external potential, and review some dynamical laws related to the 2D and 3D GPEs. By introducing a rotating Lagrangian coordinate system, the original GPEs are reformulated to GPEs without the angular momentum rotation, which is replaced by a time-dependent potential in the new coordinate system. We then cast the conserved quantities and dynamical laws in the new rotating Lagrangian coordinates. Based on the new formulation of the GPE for rotating BECs in the rotating Lagrangian coordinates, a time-splitting spectral method is presented for computing the dynamics of rotating BECs. The new numerical method is explicit, simple to implement, unconditionally stable, and very efficient in computation. It is spectral-order accurate in space and second-order accurate in time and conserves the mass on the discrete level. We compare our method with some representative methods in the literature to demonstrate its efficiency and accuracy. In addition, the numerical method is applied to test the dynamical laws of rotating BECs such as the dynamics of condensate width, angular momentum expectation, and center of mass, and to investigate numerically the dynamics and interaction of quantized vortex lattices in rotating BECs without or with the long-range DDI.Copyright © by SIAM.

  12. METHOD FOR DETERMINATION OF ROTATION CENTER IN VIBRATING OBJECT

    Directory of Open Access Journals (Sweden)

    I. P. Kauryha

    2016-01-01

    Full Text Available Linear piezoelectric gauges, eddy current transducers and other control and measuring devices have been widely applied for vibration diagnostics of objects in industry. Methods based on such gauges and used for measuring angular and linear vibrations do not provide the possibility to assess a rotation center or point angle of an object. Parasitic oscillations may occur during rotor rotation and in some cases the oscillations are caused by dis-balance. The known methods for measuring angular and linear vibrations make it possible to detect the phenomenon and they do not provide information for balancing of the given object. For this very reason the paper describes a method for obtaining instantaneous rotation center in the vibrating object. It allows to improve informational content of the measurements owing to obtaining additional data on position of object rotation center. The obtained data can be used for balancing of a control object. Essence of the given method is shown by an example of piezoelectric gauges of linear vibrations. Two three-axial gauges are fixed to the investigated object. Then gauge output signals are recalculated in angular vibrations of the object (for this purpose it is necessary to know a distance between gauges. Further projection positions of the object rotation center are determined on three orthogonal planes. Instantaneous rotation center is calculated according to the position of one of the gauges. The proposed method permits to obtain data on linear and angular vibrations and rotation center position of the vibrating object using one system of linear gauge. Possibilities of object diagnostics are expanded due to increase in number of determined parameters pertaining to object moving. The method also makes it possible to reduce material and time expenses for measurement of an angular vibration component. 

  13. Rotational diffusion of a molecular cat

    Science.gov (United States)

    Katz-Saporta, Ori; Efrati, Efi

    We show that a simple isolated system can perform rotational random walk on account of internal excitations alone. We consider the classical dynamics of a ''molecular cat'': a triatomic molecule connected by three harmonic springs with non-zero rest lengths, suspended in free space. In this system, much like for falling cats, the angular momentum constraint is non-holonomic allowing for rotations with zero overall angular momentum. The geometric nonlinearities arising from the non-zero rest lengths of the springs suffice to break integrability and lead to chaotic dynamics. The coupling of the non-integrability of the system and its non-holonomic nature results in an angular random walk of the molecule. We study the properties and dynamics of this angular motion analytically and numerically. For low energy excitations the system displays normal-mode-like motion, while for high enough excitation energy we observe regular random-walk. In between, at intermediate energies we observe an angular Lévy-walk type motion associated with a fractional diffusion coefficient interpolating between the two regimes.

  14. Canonical three-body angular basis

    International Nuclear Information System (INIS)

    Matveenko, A.V.

    2001-01-01

    Three-body problems are basic for the quantum mechanics of molecular, atomic, or nuclear systems. We demonstrate that their variational solution for rotational states can be greatly simplified. A special choice of coordinates (hyperspherical) and of the kinematics (body-fixed coordinate frame) allows one to choose basis functions in a form that makes the angular coupling trivial. (author)

  15. Alignment in the transverse plane, but not sagittal or coronal plane, affects the risk of recurrent patella dislocation.

    Science.gov (United States)

    Takagi, Shigeru; Sato, Takashi; Watanabe, Satoshi; Tanifuji, Osamu; Mochizuki, Tomoharu; Omori, Go; Endo, Naoto

    2017-11-17

    Abnormalities of lower extremity alignment (LEA) in recurrent patella dislocation (RPD) have been studied mostly by two-dimensional (2D) procedures leaving three-dimensional (3D) factors unknown. This study aimed to three-dimensionally examine risk factors for RPD in lower extremity alignment under the weight-bearing conditions. The alignment of 21 limbs in 15 RPD subjects was compared to the alignment of 24 limbs of 12 healthy young control subjects by an our previously reported 2D-3D image-matching technique. The sagittal, coronal, and transverse alignment in full extension as well as the torsional position of the femur (anteversion) and tibia (tibial torsion) under weight-bearing standing conditions were assessed by our previously reported 3D technique. The correlations between lower extremity alignment and RPD were assessed using multiple logistic regression analysis. The difference of lower extremity alignment in RPD between under the weight-bearing conditions and under the non-weight-bearing conditions was assessed. In the sagittal and coronal planes, there was no relationship (statistically or by clinically important difference) between lower extremity alignment angle and RPD. However, in the transverse plane, increased external tibial rotation [odds ratio (OR) 1.819; 95% confidence interval (CI) 1.282-2.581], increased femoral anteversion (OR 1.183; 95% CI 1.029-1.360), and increased external tibial torsion (OR 0.880; 95% CI 0.782-0.991) were all correlated with RPD. The tibia was more rotated relative to femur at the knee joint in the RPD group under the weight-bearing conditions compared to under the non-weight-bearing conditions (p alignment parameters in the transverse plane related to the risk of RPD, while in the sagittal and coronal plane alignment parameters did not correlate with RPD. The clinical importance of this study is that the 3D measurements more directly, precisely, and sensitively detect rotational parameters associated with RPD and

  16. Rotationally invariant correlation filtering

    International Nuclear Information System (INIS)

    Schils, G.F.; Sweeney, D.W.

    1985-01-01

    A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

  17. Angular momentum coupling in atom-atom collisions

    International Nuclear Information System (INIS)

    Grosser, J.

    1986-01-01

    The coupling between the electronic angular momentum and the rotating atom-atom axis in the initial or the final phase of an atom-atom collision is discussed, making use of the concepts of radial and rotational (Coriolis) coupling between different molecular states. The description is based on a limited number of well-understood approximations, and it allows an illustrative geometric representation of the transition from the body fixed to the space fixed motion of the electrons. (orig.)

  18. Transfer of orbital angular momentum to an optically trapped low-index particle

    International Nuclear Information System (INIS)

    Garces-Chavez, V.; Sibbett, W.; Dholakia, K.; Volke-Sepulveda, K.; Chavez-Cerda, S.

    2002-01-01

    We demonstrate the transfer of orbital angular momentum from a light beam to a trapped low-index particle. The particle is trapped in a dark annular region of a high-order Bessel beam and rotates around the beam axis due to scattering from the helical wave fronts of the light beam. A general theoretical geometrical optics model is developed that, applied to our specific situation, corroborates tweezing and transfer of orbital angular momentum to the low-index particle. Good quantitative agreement between theory and experiment for particle rotation rates is observed

  19. Rotational distributions of molecular photoions following resonant excitation

    International Nuclear Information System (INIS)

    Poliakoff, E.D.; Chan, J.C.K.; White, M.G.

    1986-01-01

    We demonstrate that the photoelectron energy mediates the rotational energy distribution of N + 2 ions created by photoionization, and conversely, that rotational energy determinations probe resonant excitation in molecular photoionization. Experimentally, this is accomplished by monitoring the dispersed fluorescence from N + 2 (B 2 Σ + /sub u/) photoions to determine their rotational energy distribution. These results demonstrate that while dipole selection rules constrain the total angular momentum of the electron--ion complex, the partitioning of angular momentum between the photoelectron and photoion depends on the photoejection dynamics. Implications for photoionization and electron impact ionizatin studies are discussed

  20. Evolution of magnetized, differentially rotating neutron stars: Simulations in full general relativity

    International Nuclear Information System (INIS)

    Duez, Matthew D.; Liu, Yuk Tung; Shapiro, Stuart L.; Stephens, Branson C.; Shibata, Masaru

    2006-01-01

    We study the effects of magnetic fields on the evolution of differentially rotating neutron stars, which can be formed in stellar core collapse or binary neutron star coalescence. Magnetic braking and the magnetorotational instability (MRI) both act on differentially rotating stars to redistribute angular momentum. Simulations of these stars are carried out in axisymmetry using our recently developed codes which integrate the coupled Einstein-Maxwell-MHD equations. We consider stars with two different equations of state (EOS), a gamma-law EOS with Γ=2, and a more realistic hybrid EOS, and we evolve them adiabatically. Our simulations show that the fate of the star depends on its mass and spin. For initial data, we consider three categories of differentially rotating, equilibrium configurations, which we label normal, hypermassive and ultraspinning. Normal configurations have rest masses below the maximum achievable with uniform rotation, and angular momentum below the maximum for uniform rotation at the same rest mass. Hypermassive stars have rest masses exceeding the mass limit for uniform rotation. Ultraspinning stars are not hypermassive, but have angular momentum exceeding the maximum for uniform rotation at the same rest mass. We show that a normal star will evolve to a uniformly rotating equilibrium configuration. An ultraspinning star evolves to an equilibrium state consisting of a nearly uniformly rotating central core, surrounded by a differentially rotating torus with constant angular velocity along magnetic field lines, so that differential rotation ceases to wind the magnetic field. In addition, the final state is stable against the MRI, although it has differential rotation. For a hypermassive neutron star, the MHD-driven angular momentum transport leads to catastrophic collapse of the core. The resulting rotating black hole is surrounded by a hot, massive, magnetized torus undergoing quasistationary accretion, and a magnetic field collimated along

  1. Angular momentum in QGP holography

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2014-10-01

    Full Text Available The quark chemical potential is one of the fundamental parameters describing the quark–gluon plasma produced by sufficiently energetic heavy-ion collisions. It is not large at the extremely high temperatures probed by the LHC, but it plays a key role in discussions of the beam energy scan programmes at the RHIC and other facilities. On the other hand, collisions at such energies typically (that is, in peripheral collisions give rise to very high values of the angular momentum density. Here we explain that holographic estimates of the quark chemical potential of a rotating sample of plasma can be very considerably improved by taking the angular momentum into account.

  2. Angular momentum alignment in molecular beam scattering

    International Nuclear Information System (INIS)

    Treffers, M.A.

    1985-01-01

    It is shown how the angular momentum alignment in a molecular beam can be determined using laser-induced fluorescence in combination with precession of the angular momenta in a magnetic field. After a general analysis of the method, some results are presented to illustrate the possibilities of the method. Experimental data are presented on the alignment production for Na 2 molecules that made a collision induced angular momentum transition. Magnitude as well as direction of the alignment have been determined for scattering with several scattering partners and for a large number of scattering angles and transitions. The last chapter deals with the total alignment production in a final J-state, i.e. without state selection of the initial rotational state. (orig.)

  3. Numerical study of rotating interstellar clouds: equilibrium and collapse

    International Nuclear Information System (INIS)

    Norman, M.L.

    1980-06-01

    Equilibrium and collapse of rotating, axisymmetric, idealized interstellar gas clouds is calculated with a 2D hydrodynamics code. The hydrodynamics features an improved angular momentum advection algorithm. Angular momentum is advected consistently with mass by deriving angular momentum fluxes from mass fluxes and the local distribution of specific angular momentum. Local conservation is checked by a graph of mass versus specific angular momentum for the cloud as a whole

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

    Science.gov (United States)

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

    2010-10-01

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

  5. The usefulness of sagittal reformation for diagnosis of sternal fracture

    Energy Technology Data Exchange (ETDEWEB)

    Im, Dong Jin; Hahn, Seok; Kim, Young Ju [Dept. of Radiology, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of)

    2014-01-15

    The purpose of our study was to evaluate the usefulness of sagittal reformation of chest computed tomography for the diagnosis of sternal fracture after trauma. We retrospectively reviewed medical records and chest computer tomography (CT) of 716 patients in the emergency department after trauma between January and December 2010. Two radiologists investigated chest CT images. We investigated numbers and locations of sternal fractures on axial images only and on both axial and sagittal images for each radiologist. First, radiologist found sternal fractures in 58 patients (70.7%) on only axial images, and 80 (97.5%) on both axial and sagittal images. Second, radiologist found fractures in 67 patients (81.7%) on axial image only and 81 (98.7%) on both axial and sagittal images. The sensitivity increased after adding sagittal reformation images for each radiologist (p < 0.05, respectively). On the axial images, the interobserver agreement was low (k 0.596) between the two radiologists. However, on both axial and sagittal images, the interobserver agreement increased (k = 0.872). Sagittal reformation of chest CT increases the chance of diagnosis for sternal fracture and leads to early diagnosis resulting in appropriate treatment.

  6. The usefulness of sagittal reformation for diagnosis of sternal fracture

    International Nuclear Information System (INIS)

    Im, Dong Jin; Hahn, Seok; Kim, Young Ju

    2014-01-01

    The purpose of our study was to evaluate the usefulness of sagittal reformation of chest computed tomography for the diagnosis of sternal fracture after trauma. We retrospectively reviewed medical records and chest computer tomography (CT) of 716 patients in the emergency department after trauma between January and December 2010. Two radiologists investigated chest CT images. We investigated numbers and locations of sternal fractures on axial images only and on both axial and sagittal images for each radiologist. First, radiologist found sternal fractures in 58 patients (70.7%) on only axial images, and 80 (97.5%) on both axial and sagittal images. Second, radiologist found fractures in 67 patients (81.7%) on axial image only and 81 (98.7%) on both axial and sagittal images. The sensitivity increased after adding sagittal reformation images for each radiologist (p < 0.05, respectively). On the axial images, the interobserver agreement was low (k 0.596) between the two radiologists. However, on both axial and sagittal images, the interobserver agreement increased (k = 0.872). Sagittal reformation of chest CT increases the chance of diagnosis for sternal fracture and leads to early diagnosis resulting in appropriate treatment.

  7. Simulation and experimental studies of a double-fiber angular displacement sensor

    Science.gov (United States)

    Zhu, Ruixue; Jing, Ruiping; Cheng, Yongjin

    2017-03-01

    A novel optical fiber angular displacement sensor is reported in this study. It gets the rotating angle of an object by means of the intensity modulation of a reflected light. The sensor probe, which is composed of an emitting fiber and a receiving fiber that are aligned along the vertical direction closely, is fixed directly on the rotating object. The measurements for axial displacement and angular displacement were operated separately. In particular, measurements for angular displacement were performed when the reflector is placed at different distances from the sensor probe separately. There is an excellent linearity between the angular displacement and the sensor output power. The results indicate that the larger the distance between the sensor probe and the reflector, the higher sensitivity the angular displacement sensor has. A theoretical model of the sensor is also developed and the simulate computation demonstrates that the theoretical results are in accordance with the experimental ones. The linear sensing range is ±7.2°, and the maximum sensitivity is 13.71%/deg. Furthermore, the hysteresis and the reproducibility of the measurement of the sensor are investigated. The designed sensor provides a kind of simple and effective method for measuring the angular displacement of a shaft system in practice due to its small size, light weight, good linearity and reproducibility.

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

    Directory of Open Access Journals (Sweden)

    Giancarmine Fasano

    2013-09-01

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

  9. The angular momentum of isolated white dwarfs

    Directory of Open Access Journals (Sweden)

    Brassard P.

    2013-03-01

    Full Text Available This is a very brief report on an ongoing program aimed at mapping the internal rotation profiles of stars through asteroseismology. Three years ago, we developed and applied successfully a new technique to the pulsating GW Vir white dwarf PG 1159−035, and were able to infer that it rotates very slowly and rigidly over some 99% of its mass. We applied the same approach to the three other GW Vir pulsators with available rotational splitting data, and found similar results. We discuss the implications of these findings on the question of the angular momentum of white dwarfs resulting from single star evolution.

  10. Modelling the turbulent transport of angular momentum in tokamak plasmas - A quasi-linear gyrokinetic approach

    International Nuclear Information System (INIS)

    Cottier, Pierre

    2013-01-01

    The magnetic confinement in tokamaks is for now the most advanced way towards energy production by nuclear fusion. Both theoretical and experimental studies showed that rotation generation can increase its performance by reducing the turbulent transport in tokamak plasmas. The rotation influence on the heat and particle fluxes is studied along with the angular momentum transport with the quasi-linear gyro-kinetic eigenvalue code QuaLiKiz. For this purpose, the QuaLiKiz code is modified in order to take the plasma rotation into account and compute the angular momentum flux. It is shown that QuaLiKiz framework is able to correctly predict the angular momentum flux including the E*B shear induced residual stress as well as the influence of rotation on the heat and particle fluxes. The major approximations of QuaLiKiz formalisms are reviewed, in particular the ballooning representation at its lowest order and the eigenfunctions calculated in the hydrodynamic limit. The construction of the quasi-linear fluxes is also reviewed in details and the quasi-linear angular momentum flux is derived. The different contributions to the turbulent momentum flux are studied and successfully compared both against non-linear gyro-kinetic simulations and experimental data. (author) [fr

  11. Nuclear elasticity applied to giant resonances of fast rotating nuclei

    International Nuclear Information System (INIS)

    Jang, S.; Bouyssy, A.

    1987-06-01

    Isoscalar giant resonances in fast rotating nuclei are investigated within the framework of nuclear elasticity by solving the equation of motion of elastic nuclear medium in a rotating frame of reference. Both Coriolis and centrifugal forces are taken into account. The nuclear rotation removes completely the azimuthal degeneracy of the giant resonance energies. Realistic large values of the angular velocity, which are still small as compared to the giant resonance frequencies, are briefly reviewed in relation to allowed high angular momenta. It is shown that for the A=150 region, the Coriolis force is dominating for small values (< ∼ 0.05) of the ratio of angular velocity to resonance frequency, whereas the centrifugal force plays a prominent part in the shift of the split resonance energies for larger values of the ratio. Typical examples of the resonance energies and their fragmentation due to both rotation and deformation are given

  12. Shape coexistence in 72Kr at finite angular momentum

    International Nuclear Information System (INIS)

    Almehed, Daniel; Walet, Niels R.

    2004-01-01

    We investigate shape coexistence in a rotating nucleus. We concentrate on the case of 72 Kr which exhibits an interesting interplay between prolate and oblate shaped states as a function of angular momentum. The calculation uses the local harmonic version of the method of self-consistent adiabatic large-amplitude collective motion. We analyse how the collective behaviour of the system changes with angular momentum and we focus on the role of non-axial shapes

  13. Sagittal balance in scoliosis associated with Marfan syndrome: a stereoradiographic three-dimensional analysis.

    Science.gov (United States)

    Glard, Yann; Pomero, Vincent; Collignon, Patrick; Skalli, Wafa; Jouve, Jean-Luc; Bollini, Gérard

    2008-03-01

    Marfan syndrome (MFS) is a genetic disease often marked by the presence of scoliosis. There is no three-dimensional analysis of the deformity in the literature. Our aim was to determine what kind of sagittal balance defines scoliosis associated with MFS, namely a flexion deformity, as it is in scoliosis associated with Chiari I or an extension deformity, as in adolescent idiopathic scoliosis (AIS). To address this issue, we compared the presence or absence of a thoracic scoliosis with the presence or absence of a segment in extension in the thoracic spine. In our series, 30 patients diagnosed with Marfan syndrome were prospectively included. In each patient, personalized three-dimensional reconstruction from T1 to L5 of the spine was made using stereoradiography. The patients were first separated based on the presence or absence of thoracic scoliosis, in order to compare this with the presence or absence of a segment in extension in the thoracic spine. They were then classified into two groups based on the presence or absence of the segment in extension (meaning containing negative values of inter-vertebral sagittal rotation) in the thoracic spine. Among scoliotic patients with a thoracic scoliosis (17 cases), there were 13 (76.5% cases) with a segment in extension in the thoracic spine and 4 with no segment in extension. Our results showed that scoliosis associated with MFS is somehow original, demonstrating a sagittal balance in extension (as AIS) in about 80% of thoracic curves, but without this characteristic feature in about 20%.

  14. Protostellar formation in rotation interstellar clouds. III. Nonaxisymmetric collapse

    International Nuclear Information System (INIS)

    Boss, A.P.

    1980-01-01

    A full three spatial-dimension gravitational hydrodynamics code has been used to follow the collapse of isothermal rotating clouds subjected to various nonaxialy symmetric perturbations (NAP). An initially axially symmetric cloud collapsed to form a ring which then fragmented into a binary protostellar system. A low thermal energy cloud with a large bar-shaped NAP collapsed and fragmented directly into a binary; higher thermal energy clouds damp out such NAPs while higher rotational rotational energy clouds produce binaries with wider separations. Fragmentation into single and binary systems has been seen. The tidal effects of other nearby protostellar clouds are shown to have an important effect upon the collapse and should not be neglected. The three-dimensional calculations indicate that isothermal interstellar clouds may fragment (with or without passing through a transitory ring phase) into protostellar objects while still in the isothermal regime. The fragments obtained have masses and specific spin angular momenta roughly a 10th that of the original cloud. Interstellar clouds and their fragments may pass through successive collapse phases with fragmentation and reduction of spin angular momentum (by conversion to orbital angular momentum and preferential accretion of low angular momentum matter) terminating in the formation of pre--main-sequence stars with the observed pre--main-sequence rotation rates

  15. Angular distribution and rotations of frame in vector meson decays into lepton pairs

    International Nuclear Information System (INIS)

    Palestini, Sandro

    2011-01-01

    We discuss how the angular distribution of lepton pairs from decays of vector mesons depends on the choice of reference frame, and provide a geometrical description of the transformations of the coefficients of the angular distribution. Invariant expressions involving all coefficients are discussed, together with bounds and consistency relations.

  16. Biomechanical evaluation of sagittal maxillary internal distraction osteogenesis in unilateral cleft lip and palate patient and noncleft patients: a three-dimensional finite element analysis.

    Science.gov (United States)

    Olmez, Sultan; Dogan, Servet; Pekedis, Mahmut; Yildiz, Hasan

    2014-09-01

    To compare the pattern and amount of stress and displacement during maxillary sagittal distraction osteogenesis (DO) between a patient with unilateral cleft lip and palate (UCLP) and a noncleft patient. Three-dimensional finite element models for both skulls were constructed. Displacements of the surface landmarks and stress distributions in the circummaxillary sutures were analyzed after an anterior displacement of 6 mm was loaded to the elements where the inferior plates of the distractor were assumed to be fixed and were below the Le Fort I osteotomy line. In sagittal plane, more forward movement was found on the noncleft side in the UCLP model (-6.401 mm on cleft side and -6.651 mm on noncleft side for the central incisor region). However, similar amounts of forward movement were seen in the control model. In the vertical plane, a clockwise rotation occurred in the UCLP model, whereas a counterclockwise rotation was seen in the control model. The mathematical UCLP model also showed higher stress values on the sutura nasomaxillaris, frontonasalis, and zygomatiomaxillaris on the cleft side than on the normal side. Not only did the sagittal distraction forces produce advancement forces at the intermaxillary sutures, but more stress was also present on the sutura nasomaxillaris, sutura frontonasalis, and sutura zygomaticomaxillaris on the cleft side than on the noncleft side.

  17. Electropumping of water with rotating electric fields

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; De Luca, Sergio; Todd, Billy

    2013-01-01

    exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum...

  18. Acute proximal junctional failure in patients with preoperative sagittal imbalance.

    Science.gov (United States)

    Smith, Micah W; Annis, Prokopis; Lawrence, Brandon D; Daubs, Michael D; Brodke, Darrel S

    2015-10-01

    Proximal junctional failure (PJF) is a recognized complication of spinal deformity surgery. Acute PJF (APJF) has recently been demonstrated to be 5.6% in the adult spinal deformity (ASD) population. The incidence and rate of return to the operating room for APJF have not been specifically investigated in individuals with sagittal imbalance. The purpose of this study was to report the incidence of APJF in patients with preoperative sagittal imbalance and the rate of return to the operating room for APJF. This study is based on a retrospective review of prospectively collected database of ASD patients. One hundred seventy-three consecutive patients were included with preoperative sagittal imbalance according to one of the following common parameters: sagittal vertical axis (SVA) greater than 50 mm, global sagittal alignment greater than 45°, or pelvic incidence minus lumbar lordosis greater than 10°. Outcome measure was presence and/or absence of APJF defined as fracture at the upper instrumented vertebra (UIV) or UIV+1, failure of UIV fixation, 15° or more proximal junctional kyphosis, or need for extension of instrumentation within 6 months of surgery. We performed radiographic measurements on X-rays at preoperative, immediate postoperative, and 6-month follow-up visits. The APJF rate was reported for the entire patient population with preoperative sagittal imbalance. Acute PJF incidence was calculated postoperatively for each of the accepted sagittal balance parameters and/or formulas. Patients with persistent postoperative sagittal imbalance were compared with the sagittally balanced group. We also assessed for threshold values. Acute PJF was observed in 60 of 173 patients (35%) and was least common in fusions with the UIV in the upper thoracic (UT) spine (p=.035). Of those who developed APJF, 21.7% required surgery. Proximal junctional kyphosis 15° or more was the most common form of APJF in fusions to the UT spine but least likely to need revision (p=.014

  19. Os acromiale: evaluation of markers for identification on sagittal and coronal oblique MR images

    Energy Technology Data Exchange (ETDEWEB)

    Uri, D.S. [University of Michigan, Dept. of Radiology, Ann Arbor, MI (United States)]|[Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia (United States); Kneeland, J.B. [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia (United States); Herzog, R. [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia (United States)

    1997-01-01

    An os acromiale is a developmental abnormality of ossification involving the anterior acromion which may contribute to impingement and rotator cuff disease. When axial MR sections do not include the acromioclavicular joint, the diagnosis of this often subtle abnormality will rest on its recognition on oblique coronal and sagittal images where it mimics the acromioclavicular joint. The identification of this anomaly is important as it frequently alters the type of surgical procedure utilized in symptomatic patients. We evaluate several imaging features which may be used to diagnose an os acromiale in these cases. (orig.). With 5 figs.

  20. Os acromiale: evaluation of markers for identification on sagittal and coronal oblique MR images

    International Nuclear Information System (INIS)

    Uri, D.S.; Kneeland, J.B.; Herzog, R.

    1997-01-01

    An os acromiale is a developmental abnormality of ossification involving the anterior acromion which may contribute to impingement and rotator cuff disease. When axial MR sections do not include the acromioclavicular joint, the diagnosis of this often subtle abnormality will rest on its recognition on oblique coronal and sagittal images where it mimics the acromioclavicular joint. The identification of this anomaly is important as it frequently alters the type of surgical procedure utilized in symptomatic patients. We evaluate several imaging features which may be used to diagnose an os acromiale in these cases. (orig.). With 5 figs

  1. FUNCTIONAL DISABILITY, SAGITTAL ALIGNMENT AND PELVIC BALANCE IN LUMBAR SPONDYLOLISTHESIS

    Directory of Open Access Journals (Sweden)

    Luis Muñiz Luna

    2016-03-01

    Full Text Available ABSTRACT Objectives: To demonstrate the recovery of lumbar sagittal pelvic alignment and sagittal pelvic balance after surgical reduction of lumbar spondylolisthesis and establish the benefits of the surgery for reduction and fixation of the lumbar spondylolisthesis with 360o circumferential arthrodesis for 2 surgical approaches by clinical and functional evaluation. Method: Eight patients with lumbar spondylolisthesis treated with surgical reduction and fixation of listhesis and segmental circumferential fusion with two surgical approaches were reviewed. They were evaluated before and after treatment with Oswestry, Visual Analogue for pain and Odom scales, performing radiographic measurement of lumbar sagittal alignment and pelvic sagittal balance with the technique of pelvic radius. Results: Oswestry scales and EVA reported improvement of symptoms after treatment in 8 cases; the Odom scale had six outstanding cases reported. The lumbar sagittal alignment presented a lumbosacral lordosis angle and a lumbopelvic lordosis angle reduced in 4 cases and increased in 4 other cases; pelvic sagittal balance increased the pelvic angle in 4 cases and decreased in 3 cases and the sacral translation of the hip axis to the promontory increased in 6 cases. Conclusion: The surgical procedure evaluated proved to be useful by modifying the lumbar sagittal alignment and the pelvic balance, besides reducing the symptoms, enabling the patient to have mobility and movement and the consequent satisfaction with the surgery.

  2. Radiographic analysis of the correlation between ossification of the nuchal ligament and sagittal alignment and segmental stability of the cervical spine in patients with cervical spondylotic myelopathy.

    Science.gov (United States)

    Ying, Jinwei; Teng, Honglin; Qian, Yunfan; Hu, Yingying; Wen, Tianyong; Ruan, Dike; Zhu, Minyu

    2018-01-01

    Background Ossification of the nuchal ligament (ONL) caused by chronic injury to the nuchal ligament (NL) is very common in instability-related cervical disorders. Purpose To determine possible correlations between ONL, sagittal alignment, and segmental stability of the cervical spine. Material and Methods Seventy-three patients with cervical spondylotic myelopathy (CSM) and ONL (ONL group) and 118 patients with CSM only (control group) were recruited. Radiographic data included the characteristics of ONL, sagittal alignment and segmental stability, and ossification of the posterior longitudinal ligament (OPLL). We performed comparisons in terms of radiographic parameters between the ONL and control groups. The correlations between ONL size, cervical sagittal alignment, and segmental stability were analyzed. Multivariate logistic regression was used to identify the independent risk factors of the development of ONL. Results C2-C7 sagittal vertical axis (SVA), T1 slope (T1S), T1S minus cervical lordosis (T1S-CL) on the lateral plain, angular displacement (AD), and horizontal displacement (HD) on the dynamic radiograph increased significantly in the ONL group compared with the control group. The size of ONL significantly correlated with C2-C7 SVA, T1S, AD, and HD. The incidence of ONL was higher in patients with OPLL and segmental instability. Cervical instability, sagittal malalignment, and OPLL were independent predictors of the development of ONL through multivariate analysis. Conclusion Patients with ONL are more likely to have abnormal sagittal alignment and instability of the cervical spine. Thus, increased awareness and appreciation of this often-overlooked radiographic finding is warranted during diagnosis and treatment of instability-related cervical pathologies and injuries.

  3. Generation and Sustainment of Plasma Rotation by ICRF Heating

    Science.gov (United States)

    Perkins, F. W.

    2000-10-01

    When tokamak plasmas are heated by the fundamental minority ion-cyclotron process, they are observed to rotate toroidally, even though this heating process introduces negligable angular momentum. This work proposes and evaluates a physics mechanism which resolves this apparent conflict. The argument has two elements. First, it is assumed that angular momentum transport is governed by a diffusion equation with a v_tor = 0 boundary condition at the plasma surface and a torque-density source. When the source consists of separated regions of positive and negative torque density, a finite central rotation velocity results, even though the volume integrated torque density - the angular momentum input - vanishes. Secondly, ions energized by the ICRF process can generate separated regions of positive and negative torque density. Heating increases their banana widths which leads to radial energetic-particle transport that must be balanced by neutralizing radial currents and a j_rB_pR torque density in the bulk plasma. Additional, comparable torque density results from collisional transfer of mechanical angular momentum from energetic particles to the bulk plasma and particle loss through banana particles impacting the wall. Monte-Carlo calculations utilizing the ORBIT code evaluate all sources of torque density and rigorously assure that no net angular momentum is introduced. Two models of ICRF heating, diffusive and instantaneous, give similar results. When the resonance location is on the LFS, the calculated rotation has the magnitude, profile, and co-current sense of Alcator C-Mod observations. For HFS resonance locations, the model predicts counter-current rotation. Scans of rotational profiles vs. resonance location, initial energy, particle loss, pitch, and qm will be presented as will the location of the velocity shear layer its scaling to a reactor.

  4. Rotation of dust plasma crystals in an axial magnetic field

    International Nuclear Information System (INIS)

    Cheung, F.; Prior, N.; Mitchell, L.

    2000-01-01

    Full text: Micron-sized melamine formaldehyde particles were introduced into argon plasma. As a result, the particles were negatively charged due to collision with the electrons within the plasma. With the right conditions, these particles formed a stable macroscopic crystal lattice, known as dust plasma crystal. In our experiment we conduct at Flinders University, we apply an external axial magnetic field to various configurations of dust plasma crystal. These configurations include small crystal lattices consisting of one to several particles, and large crystal lattices with many hundreds of particles. The magnetic field strength ranged from 0-32G and was uniform over the extent of the crystal. The crystals were observed to be rotating collectively in the left-handed direction under the influence of the axial magnetic field. In the case of the large crystals, the angular velocity was about 2 complete rotations per minute and was proportional to the applied magnetic field. The angular velocity changes only slightly depending on the plasma conditions. Neither radial variance in the angular velocity nor shear velocity in the vertical direction was observed in the crystal's rotational motion. In the case of the small crystals, we managed to rotate 2-6 particles (whether they are planar, 2 layers or tetrahedral). We discovered that the ease and the uniformity of the rotation of the different crystals increase as its rotational symmetry increases. Also an increase in the magnetic field strength will correspond to an increase in the angular velocity. Crystals in the shape of an annulus were also tested for theoretical reasons. The poster presentation will contain the experimental procedures, a detailed analysis and an explanation for such dust plasma crystal rotational motion

  5. Angular momentum transport by heat-driven g-modes in slowly pulsating B stars

    Science.gov (United States)

    Townsend, R. H. D.; Goldstein, J.; Zweibel, E. G.

    2018-03-01

    Motivated by recent interest in the phenomenon of waves transport in massive stars, we examine whether the heat-driven gravity (g) modes excited in slowly pulsating B (SPB) stars can significantly modify the stars' internal rotation. We develop a formalism for the differential torque exerted by g modes, and implement this formalism using the GYRE oscillation code and the MESASTAR stellar evolution code. Focusing first on a 4.21M⊙ model, we simulate 1 000 yr of stellar evolution under the combined effects of the torque due to a single unstable prograde g mode (with an amplitude chosen on the basis of observational constraints), and diffusive angular momentum transport due to convection, overshooting, and rotational instabilities. We find that the g mode rapidly extracts angular momentum from the surface layers, depositing it deeper in the stellar interior. The angular momentum transport is so efficient that by the end of the simulation, the initially non-rotating surface layers are spun in the retrograde direction to ≈ 30 per cent of the critical rate. However, the additional inclusion of magnetic stresses in our simulations almost completely inhibits this spin-up. Expanding our simulations to cover the whole instability strip, we show that the same general behaviour is seen in all SPB stars. After providing some caveats to contextualize our results, we hypothesize that the observed slower surface rotation of SPB stars (as compared to other B-type stars) may be the direct consequence of the angular momentum transport that our simulations demonstrate.

  6. Angular integration and inter-projection correlation effects in CT reconstruction

    International Nuclear Information System (INIS)

    Crawford, C.R.; Pele, N.J.

    1987-01-01

    CT reconstruction algorithms require snap-shot projections of an object. In order to minimize scan times, CT scanners rotate continuously which, in turn, prevents the acquisition of snap-shot projections. Acquired projections are integrals over angular position and may be correlated inter-projection. This paper shows that angular integration and inter-projection correlation introduce a radially dependent degradation of the spatial resolution and cause the image noise to vary non-linearly with radial position

  7. A New Shape Description Method Using Angular Radial Transform

    Science.gov (United States)

    Lee, Jong-Min; Kim, Whoi-Yul

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

  8. Minimizing the Translation Error in the Application of an Oblique Single-Cut Rotation Osteotomy: Where to Cut?

    Science.gov (United States)

    Dobbe, Johannes G G; Strackee, Simon D; Streekstra, Geert J

    2018-04-01

    An oblique single cut rotation osteotomy enables correcting angular bone alignment in the coronal, sagittal, and transverse planes, with just a single oblique osteotomy, and by rotating one bone segment in the osteotomy plane. However, translational malalignment is likely to exist if the bone is curved or deformed and the location of the oblique osteotomy is not obvious. In this paper, we investigate how translational malalignment depends on the osteotomy location. We further propose and evaluate by simulation in 3-D, a method that minimizes translational malalignment by varying the osteotomy location and by sliding the distal bone segment with respect to the proximal bone segment within the oblique osteotomy plane. The method is finally compared to what three surgeons achieve by manually selecting the osteotomy location in 3-D virtual space without planning in-plane translations. The minimization method optimized for length better than the surgeons did, by 3.2 mm on average, range (0.1, 9.4) mm, in 82% of the cases. A better translation in the axial plane was achieved by 4.1 mm on average, range (0.3, 14.4) mm, in 77% of the cases. The proposed method generally performs better than subjectively choosing an osteotomy position along the bone axis. The proposed method is considered a valuable tool for future alignment planning of an oblique single-cut rotation osteotomy since it helps minimizing translational malalignment.

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

    International Nuclear Information System (INIS)

    Epstein, Courtney R.; Pinsonneault, Marc H.

    2014-01-01

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

  10. Effect of trunk sagittal attitude on shoulder, thorax and pelvis three-dimensional kinematics in able-bodied subjects during gait.

    Directory of Open Access Journals (Sweden)

    Alberto Leardini

    Full Text Available It has been shown that an original attitude in forward or backward inclination of the trunk is maintained at gait initiation and during locomotion, and that this affects lower limb loading patterns. However, no studies have shown the extent to which shoulder, thorax and pelvis three-dimensional kinematics are modified during gait due to this sagittal inclination attitude. Thirty young healthy volunteers were analyzed during level walking with video-based motion analysis. Reflecting markers were mounted on anatomical landmarks to form a two-marker shoulder line segment, and a four-marker thorax and pelvis segments. Absolute and relative spatial rotations were calculated, for a total of 11 degrees of freedom. The subjects were divided into two groups of 15 according to the median of mean thorax inclination angle over the gait cycle. Preliminary MANOVA analysis assessed whether gender was an independent variable. Then two-factor nested ANOVA was used to test the possible effect of thorax inclination on body segments, planes of motion and gait periods, separately. There was no significant difference in all anthropometric and spatio-temporal parameters between the two groups, except for subject mass. The three-dimensional kinematics of the thorax and pelvis were not affected by gender. Nested ANOVA revealed group effect in all segment rotations apart those at the pelvis, in the sagittal and frontal planes, and at the push-off. Attitudes in sagittal thorax inclination altered trunk segments kinematics during gait. Subjects with a backward thorax showed less thorax-to-pelvis motion, but more shoulder-to-thorax and thorax-to-laboratory motion, less motion in flexion/extension and in lateral bending, and also less motion during push-off. This contributes to the understanding of forward propulsion and sideways load transfer mechanisms, fundamental for the maintenance of balance and the risk of falling.

  11. Optical Angular Momentum

    International Nuclear Information System (INIS)

    Arimondo, Ennio

    2004-01-01

    particles and atoms, the rotational frequency shift, the angular momentum in nonlinear optics, and the entanglement of angular momentum. An introductory part contains the historic paper by Poynting mentioned above, and another one by Beth in 1936 where the angular momentum of light was measured through a mechanical detection. It also includes a paper by Allen written in 2002 as a long foreword to a Special Issue of Journal of Optics B: Quantum and Semiclassical Optics where more recent major developments within this field were illustrated. Both experimental and theoretical aspects of orbital angular momentum are covered, the editors themselves having, in fact, contributed to developments in both aspects. A newcomer to the field will immediately realize the most important issues connected to the generation, propagation and application of laser beams with orbital angular momentum. A reader already acquainted with the main features of the topic may skip the first papers of all the sections listed above, and focus his or her attention to those papers devoted to the more recent developments. This is therefore a book to be considered with great attention by a large community. My only, minor, remark on the choice of the papers reproduced within this book is that applications to solid state physics, such as liquid crystals, are not mentioned. The field keeps expanding. For instance, very recently optical beams bearing optical angular momentum have been recognized as potential systems for doing quantum computation. Optical tweezers have defined a revolution in optical manipulation for research in the fields of biology, physical chemistry and soft condensed matter physics. The angular momentum of light also has applications in atom optics. Good textbooks are essential in establishing and expanding any field; they help broaden the interest in the field and ensure that the next generation of physicists can learn it. The present book satisfies those requirements because it provides to

  12. Reliability of cervical lordosis and global sagittal spinal balance measurements in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Vidal, Christophe; Ilharreborde, Brice; Azoulay, Robin; Sebag, Guy; Mazda, Keyvan

    2013-06-01

    Radiological reproducibility study. To assess intra and interobserver reliability of radiographic measurements for global sagittal balance parameters and sagittal spine curves, including cervical spine. Sagittal spine balance in adolescent idiopathic scoliosis (AIS) is a main issue and many studies have been reported, showing that coronal and sagittal deformities often involve sagittal cervical unbalance. Global sagittal balance aims to obtain a horizontal gaze and gravity line at top of hips when subject is in a static position, involving adjustment of each spine curvature in the sagittal plane. To our knowledge, no study did use a methodologically validated imaging analysis tool able to appreciate sagittal spine contours and distances in AIS and especially in the cervical region. Lateral full-spine low-dose EOS radiographs were performed in 75 patients divided in three groups (control subjects, AIS, operated AIS). Three observers digitally analyzed twice each radiograph and 11 sagittal measures were collected for each image. Reliability was assessed calculating intraobserver Pearson's r correlation coefficient, interobserver intra-class correlation coefficient (ICC) completed with a two-by-two Bland-Altman plot analysis. This measurement method has shown excellent intra and interobserver reliability in all parameters, sagittal curvatures, pelvic parameters and global sagittal balance. This study validated a simple and efficient tool in AIS sagittal contour analysis. It defined new relevant landmarks allowing to characterize cervical segmental curvatures and cervical involvement in global balance.

  13. Angular momentum redistribution by spiral waves in computer models of disc galaxies

    International Nuclear Information System (INIS)

    Sellwood, J.A.; James, R.A.

    1979-01-01

    It is shown that the spiral patterns which develop spontaneously in computer models of galaxies are generated through angular momentum transfer. By adjusting the distribution of mass in the rigid halo components of the models it is possible to alter radically the rotation curve of the disc component. Either trailing or leading spiral arms develop in the models, dependent only on the sense of the differential shear; no spirals are seen in models where the disc rotates uniformly. It is found that the distribution of angular momentum in the disc is altered by the spiral evolution. Although some spiral structure can be seen for a long period, the life of each pattern is very short. It is shown that resonances are of major importance even for these transient patterns. All spiral wave patterns which have been seen possess both an inner Lindblad resonance and a co-rotation resonance. (author)

  14. The rotation of P/Halley

    International Nuclear Information System (INIS)

    Sagdeev, R.Z.; Szegoe, K.; Kondor, A.; Merenyi, E.; Smith, B.A.; Larson, S.; Toth, I.

    1987-11-01

    The nucleus of the comet Halley rotates as a slightly asymmetric top, the orientation of the rotation axis (the orientation of the angular momentum vector) is b=54 deg +-15 deg, l=219 deg +-15 deg in the ecliptic system. In the case of the rotation of an asymmetric top the rotation axis is not fixed rigidly to the body, which means that while the nucleus rotates around the axis with a period of 2.2+-0.05 d, its long axis 'nods' periodically with a period of 7.4+-0.05 d. The amplitude of the 'nodding' is about 15 deg +-3 deg in both directions relative to a plane perpendicular to the rotation axis. (author) 21 refs.; 6 figs.; 2 tabs

  15. A novel upwind stabilized discontinuous finite element angular framework for deterministic dose calculations in magnetic fields.

    Science.gov (United States)

    Yang, R; Zelyak, O; Fallone, B G; St-Aubin, J

    2018-01-30

    Angular discretization impacts nearly every aspect of a deterministic solution to the linear Boltzmann transport equation, especially in the presence of magnetic fields, as modeled by a streaming operator in angle. In this work a novel stabilization treatment of the magnetic field term is developed for an angular finite element discretization on the unit sphere, specifically involving piecewise partitioning of path integrals along curved element edges into uninterrupted segments of incoming and outgoing flux, with outgoing components updated iteratively. Correct order-of-accuracy for this angular framework is verified using the method of manufactured solutions for linear, quadratic, and cubic basis functions in angle. Higher order basis functions were found to reduce the error especially in strong magnetic fields and low density media. We combine an angular finite element mesh respecting octant boundaries on the unit sphere to spatial Cartesian voxel elements to guarantee an unambiguous transport sweep ordering in space. Accuracy for a dosimetrically challenging scenario involving bone and air in the presence of a 1.5 T parallel magnetic field is validated against the Monte Carlo package GEANT4. Accuracy and relative computational efficiency were investigated for various angular discretization parameters. 32 angular elements with quadratic basis functions yielded a reasonable compromise, with gamma passing rates of 99.96% (96.22%) for a 2%/2 mm (1%/1 mm) criterion. A rotational transformation of the spatial calculation geometry is performed to orient an arbitrary magnetic field vector to be along the z-axis, a requirement for a constant azimuthal angular sweep ordering. Working on the unit sphere, we apply the same rotational transformation to the angular domain to align its octants with the rotated Cartesian mesh. Simulating an oblique 1.5 T magnetic field against GEANT4 yielded gamma passing rates of 99.42% (95.45%) for a 2%/2 mm (1%/1 mm) criterion.

  16. A novel upwind stabilized discontinuous finite element angular framework for deterministic dose calculations in magnetic fields

    Science.gov (United States)

    Yang, R.; Zelyak, O.; Fallone, B. G.; St-Aubin, J.

    2018-02-01

    Angular discretization impacts nearly every aspect of a deterministic solution to the linear Boltzmann transport equation, especially in the presence of magnetic fields, as modeled by a streaming operator in angle. In this work a novel stabilization treatment of the magnetic field term is developed for an angular finite element discretization on the unit sphere, specifically involving piecewise partitioning of path integrals along curved element edges into uninterrupted segments of incoming and outgoing flux, with outgoing components updated iteratively. Correct order-of-accuracy for this angular framework is verified using the method of manufactured solutions for linear, quadratic, and cubic basis functions in angle. Higher order basis functions were found to reduce the error especially in strong magnetic fields and low density media. We combine an angular finite element mesh respecting octant boundaries on the unit sphere to spatial Cartesian voxel elements to guarantee an unambiguous transport sweep ordering in space. Accuracy for a dosimetrically challenging scenario involving bone and air in the presence of a 1.5 T parallel magnetic field is validated against the Monte Carlo package GEANT4. Accuracy and relative computational efficiency were investigated for various angular discretization parameters. 32 angular elements with quadratic basis functions yielded a reasonable compromise, with gamma passing rates of 99.96% (96.22%) for a 2%/2 mm (1%/1 mm) criterion. A rotational transformation of the spatial calculation geometry is performed to orient an arbitrary magnetic field vector to be along the z-axis, a requirement for a constant azimuthal angular sweep ordering. Working on the unit sphere, we apply the same rotational transformation to the angular domain to align its octants with the rotated Cartesian mesh. Simulating an oblique 1.5 T magnetic field against GEANT4 yielded gamma passing rates of 99.42% (95.45%) for a 2%/2 mm (1%/1 mm) criterion.

  17. On some aspects of the semiclassical approach to giant resonances of rotating nuclei

    International Nuclear Information System (INIS)

    Winter, J.

    1985-01-01

    Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. - The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. - In its generalization from constant angular velocity to constant angular momentum, our model is used to demonstrate that cranking calculations of rotating giant resonances should be corrected for an oscillation of the cranking parameter to assure angular-momentum conservation. (orig.)

  18. EVIDENCE FOR CLUSTER TO CLUSTER VARIATIONS IN LOW-MASS STELLAR ROTATIONAL EVOLUTION

    International Nuclear Information System (INIS)

    Coker, Carl T.; Pinsonneault, Marc; Terndrup, Donald M.

    2016-01-01

    The concordance model for angular momentum evolution postulates that star-forming regions and clusters are an evolutionary sequence that can be modeled with assumptions about protostar–disk coupling, angular momentum loss from magnetized winds that saturates in a mass-dependent fashion at high rotation rates, and core-envelope decoupling for solar analogs. We test this approach by combining established data with the large h Per data set from the MONITOR project and new low-mass Pleiades data. We confirm prior results that young low-mass stars can be used to test star–disk coupling and angular momentum loss independent of the treatment of internal angular momentum transport. For slow rotators, we confirm the need for star–disk interactions to evolve the ONC to older systems, using h Per (age 13 Myr) as our natural post-disk case. There is no evidence for extremely long-lived disks as an alternative to core-envelope decoupling. However, our wind models cannot evolve rapid rotators from h Per to older systems consistently, and we find that this result is robust with respect to the choice of angular momentum loss prescription. We outline two possible solutions: either there is cosmic variance in the distribution of stellar rotation rates in different clusters or there are substantially enhanced torques in low-mass rapid rotators. We favor the former explanation and discuss observational tests that could be used to distinguish them. If the distribution of initial conditions depends on environment, models that test parameters by assuming a universal underlying distribution of initial conditions will need to be re-evaluated.

  19. EVIDENCE FOR CLUSTER TO CLUSTER VARIATIONS IN LOW-MASS STELLAR ROTATIONAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Carl T.; Pinsonneault, Marc; Terndrup, Donald M., E-mail: coker@astronomy.ohio-state.edu, E-mail: pinsono@astronomy.ohio-state.edu, E-mail: terndrup@astronomy.ohio-state.edu [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)

    2016-12-10

    The concordance model for angular momentum evolution postulates that star-forming regions and clusters are an evolutionary sequence that can be modeled with assumptions about protostar–disk coupling, angular momentum loss from magnetized winds that saturates in a mass-dependent fashion at high rotation rates, and core-envelope decoupling for solar analogs. We test this approach by combining established data with the large h Per data set from the MONITOR project and new low-mass Pleiades data. We confirm prior results that young low-mass stars can be used to test star–disk coupling and angular momentum loss independent of the treatment of internal angular momentum transport. For slow rotators, we confirm the need for star–disk interactions to evolve the ONC to older systems, using h Per (age 13 Myr) as our natural post-disk case. There is no evidence for extremely long-lived disks as an alternative to core-envelope decoupling. However, our wind models cannot evolve rapid rotators from h Per to older systems consistently, and we find that this result is robust with respect to the choice of angular momentum loss prescription. We outline two possible solutions: either there is cosmic variance in the distribution of stellar rotation rates in different clusters or there are substantially enhanced torques in low-mass rapid rotators. We favor the former explanation and discuss observational tests that could be used to distinguish them. If the distribution of initial conditions depends on environment, models that test parameters by assuming a universal underlying distribution of initial conditions will need to be re-evaluated.

  20. THE ROTATION PERIOD OF HD-77581 (VELA X-1)

    NARCIS (Netherlands)

    ZUIDERWIJK, EJ

    The rotation period of HD 77581, supergiant primary in the X-ray binary Vela X-1, is determined from an analysis of selected absorption line profiles. The rotation rate determined from He I line profiles is 0.67 +/- 0.04 times that of the binary angular velocity, corresponding to a rotation velocity

  1. Back to the future: sagittal CT in the evaluation of COPD

    International Nuclear Information System (INIS)

    Hightower, Jessica S.; Amadi, Chiemezie; Den, Elana; Schmitt, James E.; Shah, Rosita M.; Miller, Wallace T.

    2016-01-01

    To identify features of obstructive airway disease on sagittal reconstruction, compare the accuracy of findings to traditional imaging characteristics of COPD, and determine the fraction of additional cases identified using new characteristics. The study was approved by the centre's Institutional Review Board and is HIPAA compliant. Two hundred sixteen patients with HRCT and spirometry within a 3-month window were included. Four radiologists evaluated each HRCT for traditional characteristics of COPD and new quantitative and qualitative features of obstruction on axial and sagittal reconstructions. Imaging characteristics were assessed for correlation with the spirometric diagnosis of obstructive airway disease. Quantitative and qualitative findings on sagittal reconstruction are highly specific for COPD (specificity >90 %). Features of hyperinflation on sagittal reconstruction are more accurate predictors of obstruction than traditional axial measures, with greater interobserver reliability (hyperinflation left hemidiaphragm: accuracy: 70.08 % ± 2.49 %; kappa: 0.511 versus traditional measures: accuracy: 62.00 % ± 5.38 %; kappa: 0.407). Sagittal reconstruction identified 27-70 % more patients with COPD than traditional axial findings (p < 0.05). Analysis of sagittal reconstruction enables greater accuracy and specificity in the diagnosis of obstructive airway disease compared to traditional measures on axial imaging. Use of sagittal reconstructions can help identify up to 70 % more patients with COPD than traditional imaging findings alone. (orig.)

  2. Power and momentum relations in rotating magnetic field current drive

    Energy Technology Data Exchange (ETDEWEB)

    Hugrass, W N [Flinders Univ. of South Australia, Bedford Park. School of Physical Sciences

    1984-01-01

    The use of rotating magnetic fields (RMF) to drive steady currents in plasmas involves a transfer of energy and angular momentum from the radio frequency source feeding the rotating field coils to the plasma. The power-torque relationships in RMF systems are discussed and the analogy between RMF current drive and the polyphase induction motor is explained. The general relationship between the energy and angular momentum transfer is utilized to calculate the efficiency of the RMF plasma current drive. It is found that relatively high efficiencies can be achieved in RMF current drive because of the low phase velocity and small slip between the rotating field and the electron fluid.

  3. Interplay between intrinsic plasma rotation and magnetic island evolution in disruptive discharges

    Energy Technology Data Exchange (ETDEWEB)

    Ronchi, G.; Severo, J. H. F. [Universidade de São Paulo, Instituto de Física (Brazil); Salzedas, F. [Universidade do Porto, Faculdade de Engenharia (Portugal); Galvão, R. M. O., E-mail: rgalvao@if.usp.br; Sanada, E. K. [Universidade de São Paulo, Instituto de Física (Brazil)

    2016-05-15

    The behavior of the intrinsic toroidal rotation of the plasma column during the growth and eventual saturation of m/n = 2/1 magnetic islands, triggered by programmed density rise, has been carefully investigated in disruptive discharges in TCABR. The results show that, as the island starts to grow and rotate at a speed larger than that of the plasma column, the angular frequency of the intrinsic toroidal rotation increases and that of the island decreases, following the expectation of synchronization. As the island saturates at a large size, just before a major disruption, the angular speed of the intrinsic rotation decreases quite rapidly, even though the island keeps still rotating at a reduced speed. This decrease of the toroidal rotation is quite reproducible and can be considered as an indicative of disruption.

  4. On the six components of optical angular momentum

    International Nuclear Information System (INIS)

    Barnett, Stephen M

    2011-01-01

    In special relativity the angular momentum is a rank-two antisymmetric tensor with six independent components. Three of these are the familiar generators of spatial rotation, which for light have been studied at length. The remaining three, which are responsible for the Lorentz boosts, have largely been neglected. We introduce the latter and compare their properties with those of the more familiar generators of rotations. The seemingly natural separation of the generators of Lorentz boosts into spin and orbital parts fails, however, as the spin part is identically zero

  5. Anthropometric outcome of sagittal craniosynostosis following surgery

    International Nuclear Information System (INIS)

    Takagi, Toshinori; Morota, Nobuhito; Ihara, Satoshi; Kaneko, Tsuyoshi

    2011-01-01

    Several studies have shown good short-term outcomes after surgery for sagittal synostosis. However, the improvement in head shape usually regresses over the long term. The aim of this study was to compare anthropometric changes after surgery between osteoplastic expansion surgery and distraction osteogenesis for correcting sagittal synostosis. From November 2002 through December 2008, 17 patients with sagittal synostosis were analyzed. Anthropometric changes were assessed with cephalic indices obtained with computed tomography of the skull. The age of the patients at the time of surgery ranged from 2 to 25 months (mean, 8.2 months), and the follow-up period ranged from 6 to 63 months (mean, 17 months). In 16 patients, the cephalic index showed improvement immediately after surgery but gradually decreased in the follow-up period. The improving rate was decreased more after osteoplastic expansion surgery than after distraction osteogenesis (p<0.01). Although long-term follow-up is necessary, morphological improvement persists to a greater degree after distraction surgery. (author)

  6. Turbulent transport of toroidal angular momentum in low flow gyrokinetics

    International Nuclear Information System (INIS)

    Parra, Felix I; Catto, Peter J

    2010-01-01

    We derive a self-consistent equation for the turbulent transport of toroidal angular momentum in tokamaks in the low flow ordering that only requires solving gyrokinetic Fokker-Planck and quasineutrality equations correct to second order in an expansion on the gyroradius over scale length. We also show that according to our orderings the long wavelength toroidal rotation and the long wavelength radial electric field satisfy the neoclassical relation that gives the toroidal rotation as a function of the radial electric field and the radial gradients of pressure and temperature. Thus, the radial electric field can be solved for once the toroidal rotation is calculated from the transport of toroidal angular momentum. Unfortunately, even though this methodology only requires a gyrokinetic model correct to second order in gyroradius over scale length, current gyrokinetic simulations are only valid to first order. To overcome this difficulty, we exploit the smallish ratio B p /B, where B is the total magnetic field and B p is its poloidal component. When B p /B is small, the usual first order gyrokinetic equation provides solutions that are accurate enough to employ for our expression for the transport of toroidal angular momentum. We show that current δf and full f simulations only need small corrections to achieve this accuracy. Full f simulations, however, are still unable to determine the long wavelength, radial electric field from the quasineutrality equation.

  7. Pedicle subtraction osteotomy in elderly patients with degenerative sagittal imbalance.

    Science.gov (United States)

    Cho, Kyu-Jung; Kim, Ki-Tack; Kim, Whoan-Jeang; Lee, Sang-Hoon; Jung, Jae-Hoon; Kim, Young-Tae; Park, Hae-Bong

    2013-11-15

    Retrospective, radiographical analysis. To evaluate pedicle subtraction osteotomy (PSO) as a means of correcting severe degenerative sagittal imbalance in elderly patients. PSO in patients with degenerative sagittal imbalance is likely to cause more complications than in patients with iatrogenic flatback deformity. This study analyzed 34 patients who underwent fusion to the sacrum, with a minimum 2-year follow-up. Age of the patients were in the range from 58 to 73 with the mean at 65.5 years. PSO was performed at one segment in all cases, consisting of L3 (n = 26), L4 (n = 4), L2 (n = 3), and L1 (n = 1). The average number of levels fused was 8.15. Ten patients had structural interbody fusion at the lumbosacral junction. Applying PSO at one segment, the mean correction of the lordotic angle at the osteotomy site was 33.3°, of which the loss of correction (LOC) was 4.0° at the last visit. The correction of lumbar lordosis was 33.7° and the LOC was 8.5°. The sagittal C7 plumb was 215.9 mm before surgery, corrected to 35.1 mm after surgery, and changed to 95.9 mm by the last visit. The correction of the sagittal C7 plumb was 119.9 mm and the LOC was 60.9 mm. There was substantial LOC in lumbar lordosis and sagittal C7 plumb. In 10 patients with addition of posterior lumbar interbody fusion, the LOC of lumbar lordosis was 7.4°, which was less than 9° in those without it. PSO for the correction of degenerative sagittal imbalance in elderly patients resulted in correction of sagittal alignment with a significant LOC of lumbar lordosis and sagittal C7 plumb. The LOC of lumbar lordosis occurred at both the osteotomy and non-osteotomy site. The addition of anterior column support is helpful to maintain correction and reduce complications. N/A.

  8. Walking sagittal balance correction by pedicle subtraction osteotomy in adults with fixed sagittal imbalance.

    Science.gov (United States)

    Yagi, Mitsuru; Kaneko, Shinjiro; Yato, Yoshiyuki; Asazuma, Takashi; Machida, Masafumi

    2016-08-01

    Pedicle subtraction osteotomy (PSO) is widely used to treat severe fixed sagittal imbalance. However, the effect of PSO on balance has not been fully documented. The aim of this study was to assess dynamic walking balance after PSO to treat fixed sagittal imbalance. Gait and balance were assessed in 15 consecutive adult female patients who had been treated by PSO for a fixed sagittal imbalance and compare patients' preop and postop dynamic walking balance with that of 15 age- and gender-matched healthy volunteers (HV). Each patient's chart, X-rays, pre and postop SRS22 outcome scores, and ODI were reviewed. Means were compared by Mann-Whitney U test and Chi-square test. The mean age was 66.3 years (51-74 years). The mean follow-up was 2.7 years (2-3.5 years). The C7PL and GL, measured on the force platform, were both improved from 24.2 ± 7.3 cm and 27.6 ± 9.4 to 5.4 ± 2.6 cm and 7.2 ± 3.4 cm, respectively. The baseline hip ROM was significantly smaller in patients compared to HV, whereas no significant difference was observed in the knee or ankle ROM. The pelvic tilt (preop -0.4° ± 1.4°, postop 8.9° ± 1.0°), and maximum hip-extension angle (preop -1.2° ± 14.2°, postop -11.2° ± 7.2°) were also improved after surgery. Cadence (116 s/min), stance-swing ratio (stance 63.2 % vs. swing 36.8 %), and stride (98.0 cm) were all increased after surgery. On the other hand, gait velocity was significantly slower in the PSO group at both pre and postop than in HV (PSO 53.3 m/min at preop and 58.8 m/min at postop vs. HV 71.1 m/min, p = 0.04). Despite a mild residual spinal-pelvic malalignment, PSO restored sagittal alignment and balance satisfactorily and has improved the gait pattern.

  9. A rotation/magnetism analogy for the quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    McInnes, Brett, E-mail: matmcinn@nus.edu.sg

    2016-10-15

    In peripheral heavy ion collisions, the Quark–Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.

  10. EVOLUTION OF ROTATIONAL VELOCITIES OF A-TYPE STARS

    International Nuclear Information System (INIS)

    Yang Wuming; Bi Shaolan; Tian Zhijia; Meng Xiangcun

    2013-01-01

    The equatorial velocity of A-type stars undergoes an acceleration in the first third of the main sequence (MS) stage, but the velocity decreases as if the stars were not undergoing any redistribution of angular momentum in the external layers in the last stage of the MS phase. Our calculations show that the acceleration and the decrease of the equatorial velocity can be reproduced by the evolution of the differential rotation zero-age MS model with the angular momentum transport caused by hydrodynamic instabilities during the MS stage. The acceleration results from the fact that the angular momentum stored in the interiors of the stars is transported outward. In the last stage, the core and the radiative envelope are uncoupling, and the rotation of the envelope is a quasi-solid rotation; the uncoupling and the expansion of the envelope indicate that the decrease of the equatorial velocity approximately follows the slope for the change in the equatorial velocity of the model without any redistribution of angular momentum. When the fractional age 0.3 ∼ MS ∼< 0.5, the equatorial velocity remains almost constant for stars whose central density increases with age in the early stage of the MS phase, while the velocity decreases with age for stars whose central density decreases with age in the early stage of the MS phase.

  11. Relativistic Mechanics in Gravitational Fields Exterior to Rotating Homogeneous Mass Distributions within Spherical Geometry

    Directory of Open Access Journals (Sweden)

    Chifu E. N.

    2009-07-01

    Full Text Available General Relativistic metric tensors for gravitational fields exterior to homogeneous spherical mass distributions rotating with constant angular velocity about a fixed di- ameter are constructed. The coeffcients of affine connection for the gravitational field are used to derive equations of motion for test particles. The laws of conservation of energy and angular momentum are deduced using the generalized Lagrangian. The law of conservation of angular momentum is found to be equal to that in Schwarzschild’s gravitational field. The planetary equation of motion and the equation of motion for a photon in the vicinity of the rotating spherical mass distribution have rotational terms not found in Schwarzschild’s field.

  12. The stability of mandibular prognathism corrected by bilateral sagittal split osteotomies: a comparison of bi-cortical osteosynthesis and mono-cortical osteosynthesis.

    Science.gov (United States)

    Hsu, S S-P; Huang, C-S; Chen, P K-T; Ko, E W-C; Chen, Y-R

    2012-02-01

    This study evaluated the differences in surgical changes and post-surgical changes between bi-cortical and mono-cortical osteosynthesis (MCO) in the correction of skeletal Class III malocclusion with bilateral sagittal split osteotomies (BSSOs). Twenty-five patients had bi-cortical osteosynthesis (BCO), 32 patients had mono-cortical fixation. Lateral and postero-anterior cephalometric radiographs, taken at the time of surgery, before surgery, 1 month after surgery, and on completion of orthodontic treatment (mean 9.9 months after surgery), were obtained for evaluation. Cephalometric analysis and superimposition were used to investigate the surgical and post-surgical changes. Independent t-test was performed to compare the difference between the two groups. Pearson's correlations were tested to evaluate the factors related to the relapse of the mandible. The sagittal relapse rate was 20% in the bi-cortical and 25% in the mono-cortical group. The forward-upward rotation of the mandible in the post-surgical period contributed most of the sagittal relapse. There were no statistically significant differences in sagittal and vertical changes between the two groups during surgery and in the post-surgical period. No factors were found to correlate with post-surgical relapse, but the intergonial width increased more in the bi-cortical group. The study suggested that both methods of skeletal fixation had similar postoperative stability. Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Symmetries and rotational line intensities in diatomic molecules

    International Nuclear Information System (INIS)

    Veseth, L.

    1986-02-01

    The general theory of angular momenta and the full rotation group is used to reconsider the theory of the intensity factors of rotational lines in the spectra of diatomic molecules (Hoenl-London factors). It is shown that the use of the rotational symmetry (rotation matrices) leads to compact derivations of the symmetry properties of the molecular wave functions, as well as the matrix elements of the transitions operator. The present work is restricted to spin-allowed electric dipole transitions, and the general sum rule characteristic of this type of transitions is rederived by use of the general angular momentum theory. A main purpose of the present work has been to provide a unified theoretical basis for exact numerical computations of Hoenl-London factors for all types of spin-allowed electric dipole transitions in diatomic molecules. The computed Hoenl-London factors are then in the next step intended to be the basis for construction of synthetic molecular band spectra, with particular applications to upper atmosperic emissions (aurora)

  14. Accelerated rotation with orbital angular momentum modes

    CSIR Research Space (South Africa)

    Schulze, C

    2015-01-01

    Full Text Available where tight focusing is required, e.g., optical trapping and tweezing and optically driven flow for optofluidics. II. THEORY We recall that light fields with a phase factor of exp(i�ϕ), where ϕ is the azimuthal angle and � the topological charge... out that the total optical field may be viewed as two separate structures that perform independent rigid rotations. The dominant structure with the petal pattern is located in the central region of the beam. The other structure, which has rings, has a...

  15. ROTATING BULLETS FROM A VARIABLE PROTOSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xuepeng [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Arce, Héctor G. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Henning, Thomas, E-mail: xpchen@pmo.ac.cn [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2016-06-20

    We present Submillimeter Array (SMA) CO (2–1) observations toward the protostellar jet driven by SVS 13 A, a variable protostar in the NGC 1333 star-forming region. The SMA CO (2–1) images show an extremely high-velocity jet composed of a series of molecular “bullets.” Based on the SMA CO observations, we discover clear and large systematic velocity gradients, perpendicular to the jet axis, in the blueshifted and redshifted bullets. After discussing several alternative interpretations, such as twin-jets, jet precession, warped disk, and internal helical shock, we suggest that the systematic velocity gradients observed in the bullets result from the rotation of the SVS 13 A jet. From the SMA CO images, the measured rotation velocities are 11.7–13.7 km s{sup −1} for the blueshifted bullet and 4.7 ± 0.5 km s{sup −1} for the redshifted bullet. The estimated specific angular momenta of the two bullets are comparable to those of dense cores, about 10 times larger than those of protostellar envelopes, and about 20 times larger than those of circumstellar disks. If the velocity gradients are due to the rotation of the SVS 13 A jet, the significant amount of specific angular momenta of the bullets indicates that the rotation of jets/outflows is a key mechanism to resolve the so-called “angular momentum problem” in the field of star formation. The kinematics of the bullets suggests that the jet launching footprint on the disk has a radius of ∼7.2–7.7 au, which appears to support the extended disk-wind model. We note that further observations are needed to comprehensively understand the kinematics of the SVS 13 A jet, in order to confirm the rotation nature of the bullets.

  16. Lenke 1 and 5: changes in sagittal balance

    Directory of Open Access Journals (Sweden)

    Delson Valdemir Pessin

    2014-09-01

    Full Text Available OBJECTIVE: To assess in a cross-sectional study whether there are changes in sagittal balance in patients with adolescent idiopathic scoliosis Lenke types 1 and 5 compared with patients without pathology of the spine and compare the values of the parameters of normal subjects with the parameters found in the literature. METHODS: We measured the values of the parameters of sagittal balance of 21 patients with scoliosis and 14 patients without scoliosis in panoramic radiographs or simply collected data previously measured from the medical records. We compared the mean values of normal subjects, the mean values found in the literature, and the means between normal subjects and patients with scoliosis. For this, we used the Student t test. RESULTS: Using a confidence interval of 5% (p < 0.05 and the Student t test we obtained statistical significance in the comparison of two parameters of sagittal balance between normal subjects and patients with scoliosis. We observed similarities in the measurements of the average parameters of normal subjects with regard to the work already published. CONCLUSIONS: The adolescent idiopathic scoliosis causes changes in two parameters of sagittal balance with statistical significance but suggests changes in all other parameters. As for comparison with previously published work, the results were similar.

  17. An estimation of Envisat's rotational state accounting for the precession of its rotational axis caused by gravity-gradient torque

    Science.gov (United States)

    Lin, Hou-Yuan; Zhao, Chang-Yin

    2018-01-01

    The rotational state of Envisat is re-estimated using the specular glint times in optical observation data obtained from 2013 to 2015. The model is simplified to a uniaxial symmetric model with the first order variation of its angular momentum subject to a gravity-gradient torque causing precession around the normal of the orbital plane. The sense of Envisat's rotation can be derived from observational data, and is found to be opposite to the sense of its orbital motion. The rotational period is estimated to be (120.674 ± 0.068) · exp((4.5095 ± 0.0096) ×10-4 · t) s , where t is measured in days from the beginning of 2013. The standard deviation is 0.760 s, making this the best fit obtained for Envisat in the literature to date. The results demonstrate that the angle between the angular momentum vector and the negative normal of the orbital plane librates around a mean value of 8.53 ° ± 0.42 ° with an amplitude from about 0.7 ° (in 2013) to 0.5 ° (in 2015), with the libration period equal to the precession period of the angular momentum, from about 4.8 days (in 2013) to 3.4 days (in 2015). The ratio of the minimum to maximum principal moments of inertia is estimated to be 0.0818 ± 0.0011 , and the initial longitude of the angular momentum in the orbital coordinate system is 40.5 ° ± 9.3 ° . The direction of the rotation axis derived from our results at September 23, 2013, UTC 20:57 is similar to the results obtained from satellite laser ranging data but about 20 ° closer to the negative normal of the orbital plane.

  18. Rotations et moments angulaires enmécanique quantique

    Science.gov (United States)

    van de Wiele, J.

    Rotations and angular moments in quantum mechanics As in classical mechanics, rotation in quantum mechanics is a transformation which deals with angular momentum. The difference with classical mechanics comes from the fact that angular momentum is a vector operator and not a usual vector and its components do not commute. As for any transformation in quantum mechanics, to each rotation we can associate an operator which acts in state space. The expression of this operator depends on whether the rotation is passive, that is we do a rotation of the coordinate axes and the physical system is left unchanged, or active, in which case the coordinate axes are unchanged and the rotation is performed on the physical system. In the first part (Chaps. 1 and 2) of this book, details concerning both aspects are given. Following the definition of the geometrical transformation associated with the most general rotation, we give the expression of the rotation operator for specific cases. Transformation laws for scalar fields, vector fields and spinor fields are given as well as transformation laws for scalar operators, vector operators and more generally, for operators of any rank. The second part (Chaps. 3 and 4) deals with angular momentum algebra. We define the coupling coefficients of 2, 3 and 4 angular momenta as well as the recoupling coefficients. The definition of the irreductible tensor operator, which is a generalisation of scalar and vector operators, is given as well as the Wigner-Eckart theorem. The application of this theorem to more complex cases is studied. Comme en mécanique classique, la rotation en mécanique quantique est une transformation qui fait intervenir le moment cinétique. La différence avec la mécanique classique vient du fait que le moment cinétique est un opérateur vectoriel et non pas un vecteur ordinaire, et que ses composantes ne commutent pas deux-à-deux. Comme pour toute transformation en mécanique quantique, à chaque rotation est

  19. Angular momentum of phonons and its application to single-spin relaxation

    Science.gov (United States)

    Nakane, Jotaro J.; Kohno, Hiroshi

    2018-05-01

    We reexamine the relaxation process of a single spin embedded in an elastic medium, a problem studied recently by Garanin and Chudnovsky (GC) [Phys. Rev. B 92, 024421 (2015), 10.1103/PhysRevB.92.024421] from the viewpoint of angular-momentum transfer. Using Noether's theorem, we identify two distinct angular momenta of the medium, one Newtonian discussed by GC and the other field-theoretical, both of which consist of an orbital part and a spin part. For both angular momenta, we found that the orbital part is as essential as the spin part in the relaxation process. In particular, the angular-momentum transfer from the (real) spin to the Newtonian orbital part may be considered as an incipient rotation that leads to the Einstein-de Haas effect.

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

    Science.gov (United States)

    Belyaev, Mikhail A.; Quataert, Eliot

    2018-04-01

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

  1. Estudo radiológico do valor angular da cifose torácica em adolescentes Estudio radiológico del valor angular de la cifosis torácica en adolescentes Radiological study of the angular value of thoracic kyphosis in adolescents

    Directory of Open Access Journals (Sweden)

    Juan Javier Moreira Moreira

    2010-12-01

    diferentes niveles fue de 45º (T2-T12 y 35º (T5-T12 en el sexo masculino, y valor angular de 43º (T2-T12 y 30º (T5-T12 en el sexo femenino. CONCLUSIÓN: fue observada una diferencia constante de aproximadamente 5º cuando los valores angulares de la cifosis torácica fueron comparados, usando diferentes niveles (T2 a T5 como vértebra terminal craneal.OBJECTIVE: to determine the difference of the thoracic kyphosis angular values using different levels (T2 a T5 as a terminal cranial vertebra. METHODS: sagittal radiographies of one hundred healthy adolescent volunteers, who study at Escola Industrial do Serviço Social da Indústria (SESI in Ribeirão Preto SP, were evaluated the sagittal radiographies of one hundred health volunteers adolescent, that studies at Escola Industrial do SESI in Ribeirão Preto (SP, with parents consent. Ten adolescents were excluded because of flaws in the quality. The studied parameters were: the measurement of thoracic kyphosis by the Cobb method, using T2, T3, T4, T5 as a terminal proximal vertebra and T12 as a distal final vertebra. RESULTS: Ninety individuals (46 men and 44 women, aged from 13 to 15 (average of 14±6, were evaluated. The angular value of thoracic kyphosis in the different levels varied from 46º (T2 - T12 to 35º (T5 - T12 in men, and from 44º (T2- T12 to 30º (T5 - T12 in women. CONCLUSION: A constant difference of approximately 5º was observed when comparing the angular values of thoracic kyphosis using different levels (T2 - T5 as a terminal cranial vertebra.

  2. Angular momentum from CMIP5 climate change simulations, as related to Earth rotation excitation

    Science.gov (United States)

    Salstein, D.; Quinn, K.

    2012-04-01

    Atmospheric angular momentum parameters are calculated from revised scenarios of greenhouse gas concentration in use in the Coupled Model Intercomparison Project, phase 5, which investigates expected climate change. This phase includes new estimates for the so-called Representative Concentration Pathways (RCP), designed to simulate more realistically the future path of emissions of carbon dioxide and other greenhouse gases throughout the 21st century. From time series of atmosphere-ocean models that adopt these parameters, we calculate the impact on the excitations for length of day and polar motion through the course of the current century, and hence portions of the expected changes in the ERP's due to the atmosphere. We diagnose the most important geographic areas as regional sources of such variations; earlier such models revealed the particular importance of resulting relevant wind changes in the upper atmosphere of the middle latitudes and the southern hemisphere high latitudes. The spread among the RCP scenarios and among a number of different models gives us an understanding of possible uncertainties in the estimates. Earlier calculations were for the 20th and 21st centuries with less sophisticated greenhouse gas concentration scenarios. We can compare the Earth rotation excitations from the retrospective portions of the model-based estimates with atmospheric reanalyses that are in archives at the IERS Special Bureau for the Atmosphere.

  3. Rotating black holes and Coriolis effect

    Directory of Open Access Journals (Sweden)

    Chia-Jui Chou

    2016-10-01

    Full Text Available In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.

  4. Rotating black holes and Coriolis effect

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chia-Jui, E-mail: agoodmanjerry.ep02g@nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China); Wu, Xiaoning, E-mail: wuxn@amss.ac.cn [Institute of Mathematics, Academy of Mathematics and System Science, CAS, Beijing, 100190 (China); Yang, Yi, E-mail: yiyang@mail.nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China); Yuan, Pei-Hung, E-mail: phyuan.py00g@nctu.edu.tw [Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China)

    2016-10-10

    In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.

  5. From rotating atomic rings to quantum Hall states.

    Science.gov (United States)

    Roncaglia, M; Rizzi, M; Dalibard, J

    2011-01-01

    Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring. The large moment of inertia of the ring-shaped fluid facilitates the access to large angular momenta, corresponding to giant vortex states. The trapping potential is then adiabatically transformed into a harmonic confinement, which brings the interacting atomic gas in the desired quantum-Hall regime. We provide numerical evidence that for a broad range of initial angular frequencies, the giant-vortex state is adiabatically connected to the bosonic ν = 1/2 Laughlin state.

  6. Modal Analysis in Periodic, Time-Varying Systems with emphasis to the Coupling between Flexible Rotating Beams and Non-Rotating Flexible Structures

    DEFF Research Database (Denmark)

    Saracho, C. M.; Santos, Ilmar

    2003-01-01

    The analysis of dynamical response of a system built by a non-rotating structure coupled to flexible rotating beams is the purpose of this work. The effect of rotational speed upon the beam natural frequencies is well-known, so that an increase in the angular speeds leads to an increase in beam...... natural frequencies, the so-called centrifugal stiffening. The equations of motion of such a global system present matrices with time-depending coefficients, which vary periodically with the angular rotor speed, and introduce parametric vibrations into the system response. The principles of modal analysis...... for time-invariant linear systems are expanded to investigate time-varying systems. Concepts as eigenvalues and eigenvectors, which in this special case are also time-varying, are used to analyse the dynamical response of global system. The time-varying frequencies and modes are also illustrated....

  7. A compact rotating dilution refrigerator

    Science.gov (United States)

    Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

    2013-10-01

    We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

  8. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla

    Science.gov (United States)

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1-) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI.

  9. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.

    Science.gov (United States)

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Direct coronary and sagittal computerized tomography of the pelvis

    International Nuclear Information System (INIS)

    Maier, W.; Bargon, G.

    1981-01-01

    Whereas quite a number of reports have been published on direct coronary and sagittal computed tomography of the cranium, no extensive experience has been collected on multidimensional computerized tomography of the pelvis. In this article, the authors report on their preliminary experiences in direct approximately sagittal and coronary computerized tomography of the pelvis in a group of 76 patients. (orig.) [de

  11. Spinal Schmorl's nodes: Sagittal sectional imaging and pathological examination

    International Nuclear Information System (INIS)

    Silberstein, M.; Opeskin, K.

    1999-01-01

    The presence, location and number of Schmorl's nodes was determined in the thoracolumbar spines of 70 motor vehicle accident victims using radiographic examination of a midline sagittal section and subsequent pathological examinations, including histology. In 28% of spines, a greater number of Schmorl's nodes were identified with radiography, while in 44%, pathological examination revealed a greater number of nodes. The visibility of Schmorl's nodes was enhanced by using a sagittal radiographic approach, and, in contrast to previous work, nodes below 0.5 cm 2 were readily detected. The results of the present study offer an additional imaging technique for postmortem analysis of the spine, and support the use of sagittal MR imaging for the evaluation of this condition. Copyright (1999) Blackwell Science Pty Ltd

  12. Precise measurement of velocity dependent friction in rotational motion

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Junaid; Hassan, Hafsa; Shamim, Sohaib; Mahmood, Waqas; Anwar, Muhammad Sabieh, E-mail: sabieh@lums.edu.pk [School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore 54792 (Pakistan)

    2011-09-15

    Frictional losses are experimentally determined for a uniform circular disc exhibiting rotational motion. The clockwise and anticlockwise rotations of the disc, that result when a hanger tied to a thread is released from a certain height, give rise to vertical oscillations of the hanger as the thread winds and unwinds over a pulley attached to the disc. It is thus observed how the maximum height is achieved by the hanger decrements in every bounce. From the decrements, the rotational frictional losses are measured. The precision is enhanced by correlating vertical motion with the angular motion. This method leads to a substantial improvement in precision. Furthermore, the frictional torque is shown to be proportional to the angular speed. The experiment has been successfully employed in the undergraduate lab setting.

  13. Estimating the accuracy of the technique of reconstructing the rotational motion of a satellite based on the measurements of its angular velocity and the magnetic field of the Earth

    Science.gov (United States)

    Belyaev, M. Yu.; Volkov, O. N.; Monakhov, M. I.; Sazonov, V. V.

    2017-09-01

    The paper has studied the accuracy of the technique that allows the rotational motion of the Earth artificial satellites (AES) to be reconstructed based on the data of onboard measurements of angular velocity vectors and the strength of the Earth magnetic field (EMF). The technique is based on kinematic equations of the rotational motion of a rigid body. Both types of measurement data collected over some time interval have been processed jointly. The angular velocity measurements have been approximated using convenient formulas, which are substituted into the kinematic differential equations for the quaternion that specifies the transition from the body-fixed coordinate system of a satellite to the inertial coordinate system. Thus obtained equations represent a kinematic model of the rotational motion of a satellite. The solution of these equations, which approximate real motion, has been found by the least-square method from the condition of best fitting between the data of measurements of the EMF strength vector and its calculated values. The accuracy of the technique has been estimated by processing the data obtained from the board of the service module of the International Space Station ( ISS). The reconstruction of station motion using the aforementioned technique has been compared with the telemetry data on the actual motion of the station. The technique has allowed us to reconstruct the station motion in the orbital orientation mode with a maximum error less than 0.6° and the turns with a maximal error of less than 1.2°.

  14. A rotation/magnetism analogy for the quark–gluon plasma

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2016-10-01

    Full Text Available In peripheral heavy ion collisions, the Quark–Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.

  15. The Role of Spatial Memory and Frames of Reference in the Precision of Angular Path Integration

    OpenAIRE

    Arthur, Joeanna C.; Philbeck, John W.; Kleene, Nicholas J.; Chichka, David

    2012-01-01

    Angular path integration refers to the ability to maintain an estimate of self-location after a rotational displacement by integrating internally-generated (idiothetic) self-motion signals over time. Previous work has found that non-sensory inputs, namely spatial memory, can play a powerful role in angular path integration (Arthur et al., 2007, 2009). Here we investigated the conditions under which spatial memory facilitates angular path integration. We hypothesized that the benefit of spatia...

  16. Rotational spectroscopy with an optical centrifuge.

    Science.gov (United States)

    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.

  17. Mixed convection of ferrofluids in a lid driven cavity with two rotating cylinders

    Directory of Open Access Journals (Sweden)

    Fatih Selimefendigil

    2015-09-01

    Full Text Available Mixed convection of ferrofluid filled lid driven cavity in the presence of two rotating cylinders were numerically investigated by using the finite element method. The cavity is heated from below, cooled from driven wall and rotating cylinder surfaces and side vertical walls of the cavity are assumed to be adiabatic. A magnetic dipole source is placed below the bottom wall of the cavity. The study is performed for various values of Reynolds numbers (100 ≤ Re ≤ 1000, angular rotational speed of the cylinders (−400 ≤ Ω ≤ 400, magnetic dipole strengths (0 ≤ γ ≤ 500, angular velocity ratios of the cylinders (0.25≤Ωi/Ωj≤4 and diameter ratios of the cylinders (0.5≤Di/Dj≤2. It is observed that flow patterns and thermal transport within the cavity are affected by variation in Reynolds number and magnetic dipole strength. The results of this investigation revealed that cylinder angular velocities, ratio of the angular velocities and diameter ratios have profound effect on heat transfer enhancement within the cavity. Averaged heat transfer enhancements of 181.5 % is achieved for clockwise rotation of the cylinder at Ω = −400 compared to motionless cylinder case. Increasing the angular velocity ratio from Ω2/Ω1=0.25 to Ω2/Ω1=4 brings about 91.7 % of heat transfer enhancement.

  18. Asteroseismic measurement of surface-to-core rotation in a main-sequence star*

    Directory of Open Access Journals (Sweden)

    Kurtz Donald W.

    2015-01-01

    Full Text Available We have discovered rotationally split core g-mode triplets and surface p-mode triplets and quintuplets in a terminal age main-sequence A star, KIC 11145123, that shows both δ Sct p-mode pulsations and γ Dor g-mode pulsations. This gives the first robust determination of the rotation of the deep core and surface of a main-sequence star, essentially model-independently. We find its rotation to be nearly uniform with a period near 100 d, but we show with high confidence that the surface rotates slightly faster than the core. A strong angular momentum transfer mechanism must be operating to produce the nearly rigid rotation, and a mechanism other than viscosity must be operating to produce a more rapidly rotating surface than core. Our asteroseismic result, along with previous asteroseismic constraints on internal rotation in some B stars, and measurements of internal rotation in some subgiant, giant and white dwarf stars, has made angular momentum transport in stars throughout their lifetimes an observational science.

  19. for the internal rotation evolution of low-mass stars

    Directory of Open Access Journals (Sweden)

    Pinçon Charly

    2017-01-01

    Full Text Available Due to the space-borne missions CoRoT and Kepler, noteworthy breakthroughs have been made in our understanding of stellar evolution, and in particular about the angular momentum redistribution in stellar interiors. Indeed, the high-precision seismic data provide with the measurement of the mean core rotation rate for thousands of low-mass stars from the subgiant branch to the red giant branch. All these observations exhibit much lower core rotation rates than expected by current stellar evolution codes and they emphasize the need for an additional transport process. In this framework, internal gravity waves (herefater, IGW could play a signifivative role since they are known to be able to transport angular momentum. In this work, we estimate the effciency of the transport by the IGW that are generated by penetrative convection at the interface between the convective and the radiative regions. As a first step, this study is based on the comparison between the timescale for the waves to modify a given rotation profile and the contraction/expansion timescale throughout the radiative zone of 1.3M⊙ stellar models. We show that IGW, on their own, are ineffcient to slow down the core rotation of stars on the red giant branch, where the radiative damping becomes strong enough and prevent the IGW from reaching the innermost layers. However, we find that IGW generated by penetrative convection could effciently modify the core rotation of subgiant stars as soon as the amplitude of the radial differential rotation between the core and the base of the convective zone is high enough, with typical values close to the observed rotation rates in these stars. This result argues for the necessity to account for IGW generated by penetrative convection in stellar modeling and in the angular momentum redistribution issue.

  20. Evaluation of Andrews' Analysis as a Predictor of Ideal Sagittal Maxillary Positioning in Orthognathic Surgery.

    Science.gov (United States)

    Resnick, Cory M; Kim, Somi; Yorlets, Rachel R; Calabrese, Carly E; Peacock, Zachary S; Kaban, Leonard B

    2018-03-22

    There is no universally accepted method for determining the ideal sagittal position of the maxilla in orthognathic surgery. In "Element II" of "The Six Elements of Orofacial Harmony," Andrews used the forehead to define the goal maxillary position. The purpose of this study was to compare how well this analysis correlated with postoperative findings in patients who underwent bimaxillary orthognathic surgery planned using other guidelines. The authors hypothesized that the Andrews analysis would more consistently reflect clinical outcomes than standard angular and linear measurements. This is a retrospective cohort study of patients who had bimaxillary orthognathic surgery and achieved an acceptable esthetic outcome. Patients with no maxillary sagittal movement, obstructive sleep apnea, cleft or craniofacial diagnoses, or who were non-Caucasian were excluded. Treatment plans were developed using photographs, radiographs, and standard cephalometric measurements. The Andrews analysis, measuring the distance from the maxillary incisor to the goal anterior limit line, and standard measurements were applied to end-treatment records. The Andrews analysis was statistically compared with standard methods. There were 493 patients who had orthognathic surgery from 2007 through 2014, and 60 (62% women; mean age, 22.1 ± 6.8 yr) met the criteria for inclusion in this study. The mean Andrews distances were -4.8 ± 2.9 mm for women and -8.6 ± 4.6 mm for men preoperatively and -0.6 ± 2.1 mm for women and -1.9 ± 3.4 mm for men postoperatively. For women, the Andrews analysis was closer to the goal value (0 mm) postoperatively than any standard measurement (P Andrews analysis. The Andrews analysis correlated well with the final esthetic sagittal maxillary position in the present sample, particularly for women, and could be a useful tool for orthognathic surgical planning. Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by

  1. A review of what numerical simulations tell us about the internal rotation of the sun

    International Nuclear Information System (INIS)

    Glatzmaier, G.A.

    1986-01-01

    The simulated solar differential rotation from two independent numerical modeling efforts agree with each other and with present solar observations. The models solve the nonlinear, three-dimensional, time-dependent, anelastic equations of motion for thermal convection in a stratified, rotating, spherical shell. The simulated angular velocity in the convection zone is constant on cylinders coaxial with the rotation axis, maximum at the equator and decreasing with depth. The latitudinal variation of this angular velocity at the surface is in agreement with Doppler measurements of the solar surface rotation rate. The radial variation through the convection zone is consistent with the analysis of the rotational frequency splitting of solar oscillations. 15 refs., 5 figs

  2. Comparison of Theory with Rotation Measurements in JET ICRH Plasmas

    International Nuclear Information System (INIS)

    R.V. Budny; C.S. Chang; C. Giroud; R.J. Goldston; D. McCune; J. Ongena; F.W. Perkins; R.B. White; K.-D. Zastrow; and contributors to the EFDA-JET work programme

    2001-01-01

    Plasma rotation appears to improve plasma performance by increasing the E x B flow shearing rate, thus decreasing radial correlations in the microturbulence. Also, plasma rotation can increase the stability to resistive MHD modes. In the Joint European Torus (JET), toroidal rotation rates omega (subscript ''tor'') with high Mach numbers are generally measured in NBI-heated plasmas (since the neutral beams aim in the co-plasma current direction). They are considerably lower with only ICRH (and Ohmic) heating, but still surprisingly large considering that ICRH appears to inject relatively small amounts of angular momentum. Either the applied torques are larger than naively expected, or the anomalous transport of angular momentum is smaller than expected. Since ICRH is one of the main candidates for heating next-step tokamaks, and for creating burning plasmas in future tokamak reactors, this paper attempts to understand ICRH-induced plasma rotation

  3. The Spectrum of Electromagnetic Scatter from an Ensemble of Bodies with Angular Periodicity, as a Model for Jet Engine Modulation

    National Research Council Canada - National Science Library

    Cashman, John

    2001-01-01

    A rotating ensemble of bodies of arbitrary shape with angular periodicity scatters an electromagnetic wave to produce a spectrum of frequency components characteristic of the structure and its rotation...

  4. Pair correlation of super-deformed rotation band

    International Nuclear Information System (INIS)

    Shimizu, Yoshio

    1989-01-01

    The effect of pair correlation, one of the most important residual interactions associated with the super-deformed rotation band, is discussed in terms of the characteristics of the rotation band (its effect on the moment of inertia in particular), and the tunneling into an normal deformed state in relation to its effect on the angular momentum dependence of the potential energy plane as a function of the deformation. The characteristics of the rotation band is discussed in terms of the kinematic and dynamic momenta of inertia. It is shown that the pair correlation in a super-deformed rotation band acts to decrease the former and increase the latter momentum mainly due to dynamic pair correlation. A theoretical approach that takes this effect into account can provide results that are consistent with measured momenta, although large differences can occur in some cases. Major conflicts include a large measured kinetic momentum of inertia compared to the theoretical value, and the absence of the abnormality (shape increase) generally seen in low-spin experiments. The former seems likely to be associated with the method of measuring the angular momentum. (N.K.)

  5. A new CMOS Hall angular position sensor

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, R.S.; Drljaca, P. [Swiss Federal Inst. of Tech., Lausanne (Switzerland); Schott, C.; Racz, R. [SENTRON AG, Zug (Switzerland)

    2001-06-01

    The new angular position sensor consists of a combination of a permanent magnet attached to a shaft and of a two-axis magnetic sensor. The permanent magnet produces a magnetic field parallel with the magnetic sensor plane. As the shaft rotates, the magnetic field also rotates. The magnetic sensor is an integrated combination of a CMOS Hall integrated circuit and a thin ferromagnetic disk. The CMOS part of the system contains two or more conventional Hall devices positioned under the periphery of the disk. The ferromagnetic disk converts locally a magnetic field parallel with the chip surface into a field perpendicular to the chip surface. Therefore, a conventional Hall element can detect an external magnetic field parallel with the chip surface. As the direction of the external magnetic field rotates in the chip plane, the output voltage of the Hall element varies as the cosine of the rotation angle. By placing the Hall elements at the appropriate places under the disk periphery, we may obtain the cosine signals shifted by 90 , 120 , or by any other angle. (orig.)

  6. A new uncertainty relation for angular momentum and angle

    International Nuclear Information System (INIS)

    Kranold, H.U.

    1984-01-01

    An uncertainty relation of the form ΔL 2 ΔSo >=sup(h/2π)/sub(2) is derived for angular momentum and angle. The non-linear operator So measures angles and has a simple interpretation. Subject to very general conditions of rotational invariance the above relation is unique. Radial momentum is not quantized

  7. Prospect of Continuous VLBI Measurement of Earth Rotation in Monitoring Geophysical Fluids

    Science.gov (United States)

    Chao, Benjamin F.; Ma, Chopo; Clark, Thomas

    1998-01-01

    Large-scale mass transports in the geophysical fluids of the Earth system excite Earth's rotational variations in both length-of-day and polar motion. The excitation process is via the conservation of angular momentum. Therefore Earth rotation observations contain information about the integrated angular momentum (consisting of both the mass term and the motion term) of the geophysical fluids, which include atmosphere, hydrosphere, mantle, and the outer and inner cores. Such global information is often important and otherwise unattainable depending on the nature of the mass transport, its magnitude and time scale. The last few years have seen great advances in VLBI measurement of Earth rotation in precision and temporal resolution. These advances have opened new. areas in geophysical fluid studies, such as oceanic tidal angular momentum, atmospheric tides, Earth librations, and rapid atmospheric angular momentum fluctuations. Precision of 10 microseconds in UTI and 200 microarcseconds in polar motion can now be achieved on hourly basis. Building upon this heritage, the multi-network geodetic VLBI project, Continuous Observation of the Rotation of the Earth (CORE), promises to further these studies and to make possible studies on elusive but tell-tale geophysical processes such as oscillatory modes in the core and in the atmosphere. Currently the early phase of CORE is underway. Within a few years into the new mellinnium, the upcoming space gravity missions (such as GRACE) will measure the temporal variations in Earth's gravitational field, thus providing complementary information to that from Earth rotation study for a better understanding of global geophysical fluid processes.

  8. Influence of rotation on multiphoton processes in HF

    International Nuclear Information System (INIS)

    Broeckhove, J.; Feyen, B.; Van Leuven, P.

    1994-01-01

    In this contribution, the authors are concerned with the role of rotational motion in multiphoton processes induced by a laser field of high intensity. The authors use the pseudospectral split operator method for the propagation of the quantum wave-function. The rotation is treated by decomposition of the HF wave-function in its angular momentum components

  9. Differential rotation and the solar dynamo

    International Nuclear Information System (INIS)

    Stix, M.

    1976-01-01

    A number of numerical models for the generation of mean magnetic fields is examined and the fields are compared with the mean field of the Sun. In particular, αω-dynamos, which are based on differential rotation and cyclonic turbulence, are studied in the case of cylindrical surfaces of isorotation. Such dynamos have an oscillatory antisymmetric field as the most easily excited mode. Only models with an angular velocity which increases with increasing depth appear to be compatible with observations. A search for oscillatory ω x j-dynamos, where the α-effect is replaced by a different mean electric field perpendicular to the rotation vector ω and the mean current density j is also made. Oscillatory modes do exist for models with radial shear. Their migration is equatorwards for inwards increasing angular velocity. (orig./BJ) [de

  10. Electromyographic study of rotator cuff muscle activity during full and empty can tests

    Directory of Open Access Journals (Sweden)

    Yoshihiro Kai

    2015-01-01

    Full Text Available The empty can (EC and full can (FC tests are used as diagnostic tools for patients with rotator cuff disease. However, recently concerns have been raised that these tests do not selectively activate the muscle. Therefore, the purpose of this study was to evaluate the rotator cuff muscle activation levels during the EC and FC tests in various positions using electromyography. Twelve healthy, right-handed men without shoulder complaints (mean age: 26.1 years, range: 23–35 years were included. The tests were performed isometrically with the shoulder elevated at 45° and 90° in the sagittal, scapular, and coronal planes, either in the thumb-up (FC test or thumb-down (EC test positions. During these positions, the electromyographic signal was recorded simultaneously from the four shoulder muscles using a combination of surface and intramuscular fine-wire electrodes. The average activation of the supraspinatus and subscapularis was greater during the EC test than during the FC test and in the scapular and coronal planes than in the sagittal plane at 90°. For the infraspinatus, there were no significant differences in any positions between the two tests. Thus, the rotator cuff muscles are influenced by arm position and the elevation plane during the EC and FC tests.

  11. Spin currents of charged Dirac particles in rotating coordinates

    Science.gov (United States)

    Dayi, Ö. F.; Yunt, E.

    2018-03-01

    The semiclassical Boltzmann transport equation of charged, massive fermions in a rotating frame of reference, in the presence of external electromagnetic fields is solved in the relaxation time approach to establish the distribution function up to linear order in the electric field in rotating coordinates, centrifugal force and the derivatives. The spin and spin current densities are calculated by means of this distribution function at zero temperature up to the first order. It is shown that the nonequilibrium part of the distribution function yields the spin Hall effect for fermions constrained to move in a plane perpendicular to the angular velocity and magnetic field. Moreover it yields an analogue of Ohm's law for spin currents whose resistivity depends on the external magnetic field and the angular velocity of the rotating frame. Spin current densities in three-dimensional systems are also established.

  12. Low-dimensional organization of angular momentum during walking on a narrow beam

    OpenAIRE

    Chiovetto, Enrico; Huber, Meghan E.; Sternad, Dagmar; Giese, Martin A.

    2018-01-01

    Walking on a beam is a challenging motor skill that requires the regulation of upright balance and stability. The difficulty in beam walking results from the reduced base of support compared to that afforded by flat ground. One strategy to maintain stability and hence avoid falling off the beam is to rotate the limb segments to control the body’s angular momentum. The aim of this study was to examine the coordination of the angular momentum variations during beam walking. We recorded movement...

  13. Universal relations for differentially rotating relativistic stars at the threshold to collapse

    Science.gov (United States)

    Bozzola, Gabriele; Stergioulas, Nikolaos; Bauswein, Andreas

    2018-03-01

    A binary neutron star merger produces a rapidly and differentially rotating compact remnant whose lifespan heavily affects the electromagnetic and gravitational emissions. Its stability depends on both the equation of state (EOS) and the rotation law and it is usually investigated through numerical simulations. Nevertheless, by means of a sufficient criterion for secular instability, equilibrium sequences can be used as a computational inexpensive way to estimate the onset of dynamical instability, which, in general, is close to the secular one. This method works well for uniform rotation and relies on the location of turning points: stellar models that are stationary points in a sequence of equilibrium solutions with constant rest mass or angular momentum. Here, we investigate differentially rotating models (using a large number of EOSs and different rotation laws) and find that several universal relations between properly scaled gravitational mass, rest mass and angular momentum of the turning-point models that are valid for uniform rotation are insensitive to the degree of differential rotation, to high accuracy.

  14. Secular stability of rotating stars

    International Nuclear Information System (INIS)

    Imamura, J.N.; Friedman, J.L.; Durisen, R.H.

    1984-01-01

    In this work, the authors calculate the secular stability limits of rotating polytropes to nonaxisymmetric perturbations of low m. Polytropic indices ranging from 1 to 3 and several angular momentum distributions are considered. Results are most conveniently presented in terms of the t-parameter, defined as the ratio of the rotational kinetic energy to the absolute value of the gravitational energy of the fluid. Previous work on polytropes considered only the m = 2 mode, which is unstable for values of the t-parameter greater than 0.14 +- 0.01 for the n values n = 1.5 and 3 and the angular momentum distributions tested (see Durisen and Imamura 1981). The GRR secular stability limit of the m - 2 mode for the Maclaurin spheroids (n = 0) was determined by Chandrasekhar (1970). GRR stability limits of higher m modes for the Maclaurin spheroids were located approximately by Comins (1979a,b) and more precisely by Friedman (1983). 16 references, 2 tables

  15. Secular stability of rotating stars

    International Nuclear Information System (INIS)

    Imamura, J.N.; Friedman, J.L.; Durisen, R.H.

    1984-01-01

    In this work, we calculate the secular stability limits of rotating polytropes to nonaxisymmetric perturbations of low m. We consider polytropic indices ranging from 1 to 3 and several angular momentum distributions. Results are most conveniently presented in terms of the t-parameter, defined as the ratio of the rotational kinetic energy to the absolute value of the gravitational energy of the fluid. Previous work on polytropes considered only the m = 2 mode, which is unstable for values of the t-parameter greater than 0.14 +- 0.01 for the n values n = 1.5 and 3 and the angular momentum distributions tested (see Durisen and Imamura 1981). The GRR secular stability limit of the m = 2 mode for the Maclaurin spheroids (n = O) was determined by Chandrasekhar (1970). GRR stability limits of higher m modes for the Maclaurin spheroids were located approximately by Comins (1979a,b) and more precisely by Friedman (1983)

  16. Influence of implant rod curvature on sagittal correction of scoliosis deformity.

    Science.gov (United States)

    Salmingo, Remel Alingalan; Tadano, Shigeru; Abe, Yuichiro; Ito, Manabu

    2014-08-01

    Deformation of in vivo-implanted rods could alter the scoliosis sagittal correction. To our knowledge, no previous authors have investigated the influence of implanted-rod deformation on the sagittal deformity correction during scoliosis surgery. To analyze the changes of the implant rod's angle of curvature during surgery and establish its influence on sagittal correction of scoliosis deformity. A retrospective analysis of the preoperative and postoperative implant rod geometry and angle of curvature was conducted. Twenty adolescent idiopathic scoliosis patients underwent surgery. Average age at the time of operation was 14 years. The preoperative and postoperative implant rod angle of curvature expressed in degrees was obtained for each patient. Two implant rods were attached to the concave and convex side of the spinal deformity. The preoperative implant rod geometry was measured before surgical implantation. The postoperative implant rod geometry after surgery was measured by computed tomography. The implant rod angle of curvature at the sagittal plane was obtained from the implant rod geometry. The angle of curvature between the implant rod extreme ends was measured before implantation and after surgery. The sagittal curvature between the corresponding spinal levels of healthy adolescents obtained by previous studies was compared with the implant rod angle of curvature to evaluate the sagittal curve correction. The difference between the postoperative implant rod angle of curvature and normal spine sagittal curvature of the corresponding instrumented level was used to evaluate over or under correction of the sagittal deformity. The implant rods at the concave side of deformity of all patients were significantly deformed after surgery. The average degree of rod deformation Δθ at the concave and convex sides was 15.8° and 1.6°, respectively. The average preoperative and postoperative implant rod angle of curvature at the concave side was 33.6° and 17.8

  17. Rotationally resolved flurorescence as a probe of molecular photoionization dynamics

    International Nuclear Information System (INIS)

    Poliakoff, E.D.; Kakar, S.; Choi, H.C.

    1993-01-01

    We present rotationally resolved data for N 2 (2σ u -1 ) photoionization in the excitation energy range 19 ≤ hν ≤ 35 eV. These are the first rotationally resolved measurements on the photoion over an extended spectral range above the ionization threshold. The requisite resolution is obtained by measuring rotationally resolved fluorescence from electronically excited photoions created by synchrotron radiation. This technique is useful for studying dynamical features embedded deep in the ionization continua and should supplement laser-based methods that are limited to probing near-threshold phenomena. The present study shows that the outgoing photoelectron can alter the rotational motion of the more massive photoion by exchanging angular momentum and this partitioning of angular momentum depends on the ionization dynamics. Thus, our data directly probe electron-molecule interactions and are sensitive probes of scattering dynamics. We are currently investigating dynamical features such as shape resonances and Cooper minima with rotational resolution for deciphering microscopic aspects of molecular scattering and these efforts will be discussed

  18. Rotational Fourier tracking of diffusing polygons.

    Science.gov (United States)

    Mayoral, Kenny; Kennair, Terry P; Zhu, Xiaoming; Milazzo, James; Ngo, Kathy; Fryd, Michael M; Mason, Thomas G

    2011-11-01

    We use optical microscopy to measure the rotational Brownian motion of polygonal platelets that are dispersed in a liquid and confined by depletion attractions near a wall. The depletion attraction inhibits out-of-plane translational and rotational Brownian fluctuations, thereby facilitating in-plane imaging and video analysis. By taking fast Fourier transforms (FFTs) of the images and analyzing the angular position of rays in the FFTs, we determine an isolated particle's rotational trajectory, independent of its position. The measured in-plane rotational diffusion coefficients are significantly smaller than estimates for the bulk; this difference is likely due to the close proximity of the particles to the wall arising from the depletion attraction.

  19. Intracycle angular velocity control of cross-flow turbines

    Science.gov (United States)

    Strom, Benjamin; Brunton, Steven L.; Polagye, Brian

    2017-08-01

    Cross-flow turbines, also known as vertical-axis turbines, are attractive for power generation from wind and water currents. Some cross-flow turbine designs optimize unsteady fluid forces and maximize power output by controlling blade kinematics within one rotation. One established method is to dynamically pitch the blades. Here we introduce a mechanically simpler alternative: optimize the turbine rotation rate as a function of angular blade position. We demonstrate experimentally that this approach results in a 59% increase in power output over standard control methods. Analysis of fluid forcing and blade kinematics suggest that power increase is achieved through modification of the local flow conditions and alignment of fluid force and rotation rate extrema. The result is a low-speed, structurally robust turbine that achieves high efficiency and could enable a new generation of environmentally benign turbines for renewable power generation.

  20. Determination of 3D location and rotation of lumbar vertebrae in CT images by symmetry-based auto-registration

    Science.gov (United States)

    Vrtovec, Tomaž; Likar, Boštjan; Pernuš, Franjo

    2007-03-01

    Quantitative measurement of vertebral rotation is important in surgical planning, analysis of surgical results, and monitoring of the progression of spinal deformities. However, many established and newly developed techniques for measuring axial vertebral rotation do not exploit three-dimensional (3D) information, which may result in virtual axial rotation because of the sagittal and coronal rotation of vertebrae. We propose a novel automatic approach to the measurement of the location and rotation of vertebrae in 3D without prior volume reformation, identification of appropriate cross-sections or aid by statistical models. The vertebra under investigation is encompassed by a mask in the form of an elliptical cylinder in 3D, defined by its center of rotation and the rotation angles. We exploit the natural symmetry of the vertebral body, vertebral column and vertebral canal by dividing the vertebral mask by its mid-axial, mid-sagittal and mid-coronal plane, so that the obtained volume pairs contain symmetrical parts of the observed anatomy. Mirror volume pairs are then simultaneously registered to each other by robust rigid auto-registration, using the weighted sum of absolute differences between the intensities of the corresponding volume pairs as the similarity measure. The method was evaluated on 50 lumbar vertebrae from normal and scoliotic computed tomography (CT) spinal scans, showing relatively large capture ranges and distinctive maxima at the correct locations and rotation angles. The proposed method may aid the measurement of the dimensions of vertebral pedicles, foraminae and canal, and may be a valuable tool for clinical evaluation of the spinal deformities in 3D.

  1. Nonlinear model of a rotating hub-beams structure: Equations of motion

    Science.gov (United States)

    Warminski, Jerzy

    2018-01-01

    Dynamics of a rotating structure composed of a rigid hub and flexible beams is presented in the paper. A nonlinear model of a beam takes into account bending, extension and nonlinear curvature. The influence of geometric nonlinearity and nonconstant angular velocity on dynamics of the rotating structure is presented. The exact equations of motion and associated boundary conditions are derived on the basis of the Hamilton's principle. The simplification of the exact nonlinear mathematical model is proposed taking into account the second order approximation. The reduced partial differential equations of motion together with associated boundary conditions can be used to study natural or forced vibrations of a rotating structure considering constant or nonconstant angular speed of a rigid hub and an arbitrary number of flexible blades.

  2. Postoperative stability of 2-jaw surgery with clockwise rotation of the occlusal plane.

    Science.gov (United States)

    Bang, Sung-Moon; Kwon, Yong-Dae; Kim, Su-Jung; Lee, Baek-Soo; Choi, Byung-Joon; Ohe, Joo-Young; Suh, Joon-Ho

    2012-03-01

    The objective of this study was to investigate the skeletal stability after Le Fort I osteotomy with clockwise rotation and bilateral sagittal split osteotomy. The sample consisted of 31 young Korean patients who were treated with Le Fort I osteotomy with clockwise rotation and setback bilateral sagittal split osteotomy. The lateral cephalographs were obtained before surgery (T1), right after surgery (T2), and on an average of 6.23 months after the operation (T3). The horizontal and vertical relations of landmarks to the reference line and soft tissue changes were evaluated. During the T2 - T1 period, there was superior and anterior movement of the posterior part (PNS, UMD) and advancement and impaction of the anterior part (ANS, A point, UIE) of the maxilla. The mandible was moved superiorly and posteriorly. During the T3 - T2 period, maxillary segment showed counterclockwise rotational relapse. The posterior part was relatively stable especially in the vertical position and the anterior part moved in the posterior and superior directions. Mandibular landmarks showed forward relapse in the horizontal aspect and superior relapse in the vertical aspect. The posterior part (PNS and UMD) showed a significantly higher stability rate (>70%) in the vertical aspect and the anterior part of the maxilla (ANS, A point) demonstrated a significantly lower value (occlusal plane showed stable results especially in the maxillary posterior landmarks. The clockwise rotational movement can be beneficial to increase skeletal stability and facial aesthetics in Asians.

  3. Relaxation processes in rotational motion

    International Nuclear Information System (INIS)

    Broglia, R.A.

    1986-01-01

    At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

  4. A method for determining poloidal rotation from poloidal asymmetry in toroidal rotation (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Chrystal, C., E-mail: chrystal@fusion.gat.com [Department of Physics, University of California-San Diego, 9500 Gilman Dr., La Jolla, California 92093 (United States); Burrell, K. H.; Lao, L. L.; Pace, D. C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A new diagnostic has been developed on DIII-D that determines the impurity poloidal rotation from the poloidal asymmetry in the toroidal angular rotation velocity. This asymmetry is measured with recently added tangential charge exchange viewchords on the high-field side of the tokamak midplane. Measurements are made on co- and counter-current neutral beams, allowing the charge exchange cross section effect to be measured and eliminating the need for atomic physics calculations. The diagnostic implementation on DIII-D restricts the measurement range to the core (r/a < 0.6) where, relative to measurements made with the vertical charge exchange system, the spatial resolution is improved. Significant physics results have been obtained with this new diagnostic; for example, poloidal rotation measurements that significantly exceed neoclassical predictions.

  5. Control of fluid-containing rotating rigid bodies

    CERN Document Server

    Gurchenkov, Anatoly A

    2013-01-01

    This book is devoted to the study of the dynamics of rotating bodies with cavities containing liquid. Two basic classes of motions are analyzed: rotation and libration. Cases of complete and partial filling of cavities with ideal liquid and complete filling with viscous liquid are treated. The volume presents a method for obtaining relations between angular velocities perpendicular to main rotation and external force momentums, which are treated as control. The developed models and methods of solving dynamical problems as well as numerical methods for solving problems of optimal control can be

  6. Effects of solar radiation pressure torque on the rotational motion of an artificial satellite

    Science.gov (United States)

    Zanardi, Maria Cecilia F. P. S.; Vilhenademoraes, Rodolpho

    1992-01-01

    The motion of an artificial satellite about its center of mass is studied considering torques due to the gravity gradient and direct solar radiation pressure. A model for direct solar radiation torque is derived for a circular cylindrical satellite. An analytical solution is obtained by the method of variation of the parameters. This solution shows that the angular variables have secular variation but that the modulus of the rotational angular momentum, the projection of rotational angular momentum on the z axis of the moment of inertia and inertial axis z, suffer only periodic variations. Considering a hypothetical artificial satellite, a numerical application is demonstrated.

  7. Effects of Ultrafast Molecular Rotation on Collisional Decoherence

    Science.gov (United States)

    Milner, Alexander A.; Korobenko, Aleksey; Hepburn, John W.; Milner, Valery

    2014-07-01

    Using an optical centrifuge to control molecular rotation in an extremely broad range of angular momenta, we study coherent rotational dynamics of nitrogen molecules in the presence of collisions. We cover the range of rotational quantum numbers between J=8 and J =66 at room temperature and study a crossover between the adiabatic and nonadiabatic regimes of rotational relaxation, which cannot be easily accessed by thermal means. We demonstrate that the rate of rotational decoherence changes by more than an order of magnitude in this range of J values and show that its dependence on J can be described by a simplified scaling law.

  8. Superior sagittal sinus thrombosis: a rare complication of nephrotic syndrome.

    Directory of Open Access Journals (Sweden)

    Tullu M

    1999-10-01

    Full Text Available A two and half year-old-male child, known case of steroid responsive nephrotic syndrome presented with fever and vomiting of acute onset. He was diagnosed to have superior sagittal sinus thrombosis on a contrast computerised tomographic scan of brain. Recovery was complete without anticoagulant therapy. Superior sagittal sinus thrombosis is an extremely rare complication of nephrotic syndrome.

  9. Compound nuclei at high angular momentum. High-spin γ-ray spectroscopy: past successes, future hopes

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1984-01-01

    The addition of angular momentum to a nucleus presents a whole new dimension, a new coordinate axis, along which to study changes in nuclear behavior and structure. Nuclei can carry angular momentum in two principal ways: by the collective rotation of a deformed nucleus as a whole and by the alignment along the rotation axis of individual high-j nucleons. For spherical (or near-spherical) nuclei, the latter mode is the only one possible. The levels of 212 Rn illustrate a scheme of particle alignment; it is quite irregular with transitions of a variety of electromagnetic types and with little pattern to the level spacing. On the left, the yrast band of 238 U is shown, a predominantly rotational scheme with only strongly enhanced electric quadrupole transitions and a level spacing that approximates that of a rigid rotor, E = I(I + 1)h 2 /2 J and E/sub γ/ = (4I - 2)h 2 /2 J, where J is the moment of inertia. Most nuclei, however, combine both types of motion, and it is this interplay between collective and single-particle motion that makes the behavior of nuclei along the angular momentum coordinate so fascinating and so rich in variety. Data are shown for Yb isotopes, and Er isotopes are discussed

  10. Relative mobility of the pelvis and spine during trunk axial rotation in chronic low back pain patients: A case-control study.

    Directory of Open Access Journals (Sweden)

    Masashi Taniguchi

    Full Text Available Trunk axial rotation is a risk factor for chronic low back pain (CLBP. The characteristics of rotational mobility in the pelvis and spine among CLBP patients are not fully understood.The purpose of this study was to examine three-dimensional kinematic changes, and to compare the differences of rotational mobility and coupled motion, in patients with and without CLBP.Fifteen patients with CLBP and 15 age and sex matched healthy subjects participated in this study. Each subject performed trunk rotation to maximum range of motion (ROM in a standing position. The kinematics data was collected using a three-dimensional motion analysis system. The outcomes measured were the rotational ROM and the spine/pelvis ratio (SPR in transvers plane at both maximum and 50% rotation position. The coupled angles in sagittal and frontal planes were also measured.No significant differences in rotational ROM of the thorax, pelvis, and spine were observed between two groups at maximum rotation position. However, there was a significant interaction between groups and rotational ROM of pelvis and spine (F = 4.57, p = 0.04, and the SPR in CLBP patients was significantly greater than that of the healthy subjects (CLBP; 0.50 ± 0.10 Control; 0.41 ± 0.12, p = 0.04. The results at 50% rotation position were similar to that at maximum rotation. This indicates a relative increase in spinal rotation in the CLBP patients during trunk rotation. Moreover, the CLBP patients exhibited a significantly higher anterior tilt of the pelvis and extension of the spine in the sagittal plane coupled with rotation.CLBP patients had relative hyper rotational mobility of the spine as well as excessive spinal extension coupled with trunk rotation. These results suggest that uncoordinated trunk rotation might be a functional failure associated with CLBP.

  11. Does rehabilitation of cervical lordosis influence sagittal cervical spine flexion extension kinematics in cervical spondylotic radiculopathy subjects?

    Science.gov (United States)

    Moustafa, Ibrahim Moustafa; Diab, Aliaa Attiah Mohamed; Hegazy, Fatma A; Harrison, Deed E

    2017-01-01

    To test the hypothesis that improvement of cervical lordosis in cervical spondylotic radiculopathy (CSR) will improve cervical spine flexion and extension end range of motion kinematics in a population suffering from CSR. Thirty chronic lower CSR patients with cervical lordosis lordosis (p lordosis in the study group was associated with significant improvement in the translational and rotational motions of the lower cervical spine. This finding provides objective evidence that cervical flexion/extension is partially dependent on the posture and sagittal curve orientation. These findings are in agreement with several other reports in the literature; whereas ours is the first post treatment analysis identifying this relationship.

  12. An electrophysiological study of the mental rotation of polygons.

    Science.gov (United States)

    Pierret, A; Peronnet, F; Thevenet, M

    1994-05-09

    Reaction times and event-related potentials (ERPs) were recorded during a task requiring subjects to decide whether two sequentially presented polygons had the same shape regardless of differences in orientation. Reaction times increased approximately linearly with angular departure from upright orientation, which suggests that mental rotation was involved in the comparison process. The ERPs showed, between 665 and 1055 ms, a late posterior negativity also increasing with angular disparity from upright, which we assumed to reflect mental rotation. Two other activities were exhibited, from 265 to 665 ms, which may be related either to an evaluation of the stimulus or a predetermination of its orientation, and from 1055 to 1600 ms attributed to the decision process.

  13. Reproduction of superior sagittal sinus animal model by bypass transplantation of biomaterial graft

    Directory of Open Access Journals (Sweden)

    Qing-yong LUO

    2011-03-01

    Full Text Available Objective To establish the beagles model of superior sagittal sinus bypass graft,and explore the feasibility of reconstruction of superior sagittal sinus with biomaterials using this model.Methods Eight adult male beagles(weight: 12.5-22.0kg were involved in the present study.The superior sagittal sinus was exposed and blocked via bone window,and then anastomosed side-to-end to the biomaterial graft under the dedicated microscope of neurosurgery surgery,expectant treatment such as anti-inflammatory was given for the animals.The digital subtraction venography(DSV and color Doppler flow imaging(CDFI of superior sagittal sinus were performed in 1,2,4 and 8 weeks after the operation.Eight weeks after the operation,all the animals were sacrificed and the material graft was examined histologically.Results The DSV and CDFI of superior sagittal sinus showed that the stomas of 2 beagles were with slight stenosis and high flow velocity,of 1 beagle with small leakage and low flow velocity,while of other 5 beagles were normal.The histological examination showed endothelial cells were growing on the graft and superior sagittal sinus,and crawling toward the lumen of graft 8 weeks after the operation.Conclusion The beagles model of superior sagittal sinus bypass graft was established successfully.The short-term effect of the model was satisfactory,while further work should be performed to determine the long-term effects.

  14. Effect of magnetic field on the Rayleigh Taylor instability of rotating and stratified plasma

    International Nuclear Information System (INIS)

    Sharma, PK; Tiwari, Anita; Argal, Shraddha

    2017-01-01

    In the present study the effect of magnetic field and rotation have been carried out on the Rayleigh Taylor instability of conducting and rotating plasma, which is assumed to be incompressible and confined between two rigid planes z = 0 and z = h. The dispersion relation of the problem is obtained by solving the basic MHD equations of the problem with the help normal mode technique and appropriate boundary conditions. The dispersion relation of the medium is analysed and the effect of magnetic field and angular velocity (rotation effect) have been examined on the growth rate of Rayleigh Taylor instability. It is found that the magnetic field and angular velocity (rotation effect) have stabilizing influence on the Rayleigh Taylor instability. (paper)

  15. Rotating hairy black holes in arbitrary dimensions

    Science.gov (United States)

    Erices, Cristián; Martínez, Cristián

    2018-01-01

    A class of exact rotating black hole solutions of gravity nonminimally coupled to a self-interacting scalar field in arbitrary dimensions is presented. These spacetimes are asymptotically locally anti-de Sitter manifolds and have a Ricci-flat event horizon hiding a curvature singularity at the origin. The scalar field is real and regular everywhere, and its effective mass, coming from the nonminimal coupling with the scalar curvature, saturates the Breitenlohner-Freedman bound for the corresponding spacetime dimension. The rotating black hole is obtained by applying an improper coordinate transformation to the static one. Although both spacetimes are locally equivalent, they are globally different, as it is confirmed by the nonvanishing angular momentum of the rotating black hole. It is found that the mass is bounded from below by the angular momentum, in agreement with the existence of an event horizon. The thermodynamical analysis is carried out in the grand canonical ensemble. The first law is satisfied, and a Smarr formula is exhibited. The thermodynamical local stability of the rotating hairy black holes is established from their Gibbs free energy. However, the global stability analysis establishes that the vacuum spacetime is always preferred over the hairy black hole. Thus, the hairy black hole is likely to decay into the vacuum one for any temperature.

  16. A high-resolution spectropolarimetric survey of Herbig Ae/Be stars - II. Rotation

    Science.gov (United States)

    Alecian, E.; Wade, G. A.; Catala, C.; Grunhut, J. H.; Landstreet, J. D.; Böhm, T.; Folsom, C. P.; Marsden, S.

    2013-02-01

    We report the analysis of the rotational properties of our sample of Herbig Ae/Be (HAeBe) and related stars for which we have obtained high-resolution spectropolarimetric observations. Using the projected rotational velocities measured at the surface of the stars, we have calculated the angular momentum of the sample and plotted it as a function of age. We have then compared the angular momentum and the v sin i distributions of the magnetic to the non-magnetic HAeBe stars. Finally, we have predicted v sin i of the non-magnetic, non-binary (`normal') stars in our sample when they reach the zero-age main sequence (ZAMS), and compared them to various catalogues of v sin i of main-sequence stars. First, we observe that magnetic HAeBe stars are much slower rotators than normal stars, indicating that they have been more efficiently braked than the normal stars. In fact, the magnetic stars have already lost most of their angular momentum, despite their young ages (lower than 1 Myr for some of them). Secondly, our analysis suggests that the low-mass (1.5 5 M⊙) are losing angular momentum. We propose that winds, which are expected to be stronger in massive stars, are at the origin of this phenomenon.

  17. A Key Experiment of Quantum Optics: The Transfer of Spin Angular Momentum from Photons to a Birefringent Particle

    Energy Technology Data Exchange (ETDEWEB)

    Frins, E [Universidad de la Republica, Montevideo (Uruguay); Dultz, W [J.W.v.Goethe Universitaet Frankfurt/Main (Germany); Schmitzer, H, E-mail: requalivahanus@t-online.de [Xavier University, Cincinnati (United States)

    2011-01-01

    Rotating small birefringent particles with the spin angular momentum of light is a key experiment of quantum optics. We derive the equation of motion of small retarders in viscose liquids, demonstrate their some times irregular rotation in polarized light, and discuss possible technical applications.

  18. Mars: destruction of the tropical belt and building up extra tropics is a physical requirement of angular momentum equilibration between zones with different distances to the rotation axis

    Science.gov (United States)

    Kochemasov, G. G.

    2012-09-01

    Often observed a sensible difference in appearance and structure between tropical and extra-t ropical zones of various heavenly bodies including rocky and gas planets, satellites and Sun (Fig. 6) compels to look for a common reason of such phenomenon [1-3]. All bodies rotate and their spherical shape makes zones at different lat itudes to have differing angular momenta as a distance to the rotation axis diminishes gradually from the equator to the poles (Fig. 1) (this is felt particularly when one launches rockets into space -preferable cheaper launches are from the equatorial regions - Kourou in the French Guyana is better than Baikonur in Kazakhstan). One of remarkable changes occurs at tropics. As a total rotating planetary body tends to have angular momenta of its tectonic blocks equilibrated it starts mechanisms leveling this basic physical property. At tropical zones (bulged also due to the rotation ellipsoid) the outer shell - crust as a consequence tends to be destroyed, sunk, subsided and shrunk; a density of crust material changes; the atmosphere reacts changing chemistry and structure; in terrestrial anthroposphere man looses its mass and stature (well known pygmioidness process). Ext ratropical belts, on the contrary, tend to add material and increase radius. Thus, a body tends to be like a cucumber but mighty gravity always makes it globular. According to the Le Chatelier rule mechanisms with opposing tendencies also begin to act. However, traces of this cosmic "struggle" very often are seen on surfaces of heavenly bodies as structurally distinguished tropical and extra-t ropical zones (Fig. 1, 6) [1-3]. At Mars the widespread "enigmatic" chaotic and fretted terrains at the highland-lowland boundary could be considered as traces of the crust destruction along the wide tropical belt (Fig. 2-4). A system of hillocks and their relics, mesas, ridges, cliffs and separating them depressions or plains (deep up to 1-2 km) is controlled by a crosscutting

  19. Inertial rotation measurement with atomic spins: From angular momentum conservation to quantum phase theory

    Science.gov (United States)

    Zhang, C.; Yuan, H.; Tang, Z.; Quan, W.; Fang, J. C.

    2016-12-01

    Rotation measurement in an inertial frame is an important technology for modern advanced navigation systems and fundamental physics research. Inertial rotation measurement with atomic spin has demonstrated potential in both high-precision applications and small-volume low-cost devices. After rapid development in the last few decades, atomic spin gyroscopes are considered a promising competitor to current conventional gyroscopes—from rate-grade to strategic-grade applications. Although it has been more than a century since the discovery of the relationship between atomic spin and mechanical rotation by Einstein [Naturwissenschaften, 3(19) (1915)], research on the coupling between spin and rotation is still a focus point. The semi-classical Larmor precession model is usually adopted to describe atomic spin gyroscope measurement principles. More recently, the geometric phase theory has provided a different view of the rotation measurement mechanism via atomic spin. The theory has been used to describe a gyroscope based on the nuclear spin ensembles in diamond. A comprehensive understanding of inertial rotation measurement principles based on atomic spin would be helpful for future applications. This work reviews different atomic spin gyroscopes and their rotation measurement principles with a historical overlook. In addition, the spin-rotation coupling mechanism in the context of the quantum phase theory is presented. The geometric phase is assumed to be the origin of the measurable rotation signal from atomic spins. In conclusion, with a complete understanding of inertial rotation measurements using atomic spin and advances in techniques, wide application of high-performance atomic spin gyroscopes is expected in the near future.

  20. Nuclear squid: Diabolic pair transfer in rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nikam, R S; Ring, P; Canto, L F

    1987-02-19

    A new unexpected behavior of pair transfer matrix elements in superfluid rotating nuclei is predicted. With increasing angular velocity they drop to zero, change their sign and in some cases even oscillate between positive and negative values. This effect is related to diabolical points in rotating quasiparticle spectra and is closely analogous to the DC-Josephson effect in superconductors in the presence of a magnetic field.

  1. Differential Rotation within the Earth's Outer Core

    Science.gov (United States)

    Hide, R.; Boggs, D. H.; Dickey, J. O.

    1998-01-01

    Non-steady differential rotation drive by bouyancy forces within the Earth's liquid outer core (OC) plays a key role not only in the generation of the main geomagnetic field by the magnetohydrodynamic (MHD) dynamo process but also in the excitation of irregular fluctuations in the angular speed of rotation of the overlying solid mantle, as evidenced by changes in the length of the day (LOD) on decadal and longer timescales (1-8).

  2. Scaling laws for the rotational velocity of a J x B driven rotating plasma

    International Nuclear Information System (INIS)

    Igarashi, Yasuhito; Kataoka, Tomohiro; Ikehata, Takashi; Sato, Naoyuki; Tanabe, Toshio; Mase, Hiroshi

    1994-01-01

    Rapidly rotating plasmas of helium and argon have been extracted from a coaxial plasma gun operated in pulsed glow mode. The rotational velocity and its parametric dependence have been analyzed systematically by means of visible - emission spectroscopy. The plasma is observed to rotate rigidly inside the diameter of the gun anode while outside the velocity decreases rapidly ; furthermore, different ions are found to rotate at different angular frequencies as ω (Ar + ) = 0.5 x 10 6 rad/sec, ω (Ar 2+ ) = 1.1 x 10 6 rad/sec, ω (C 2+ ) = 1.8 x 10 6 rad/sec, ω (N + ) = 1.2 x 10 6 rad/sec. The plasma density and rotational velocity have been measured as a function of the discharge current and magnetic field to derive experimental scaling laws. They are summarized as : 1. Ion density is proportional to the square of discharge current. 2. Rotational and axial velocities are proportional to the driving force per ion. These results are confirmed to agree well with a theoretical prediction. (author)

  3. Rotation of White Dwarf Stars

    OpenAIRE

    Kawaler, Steven D.

    2014-01-01

    I discuss and consider the status of observational determinations of the rotation velocities of white dwarf stars via asteroseismology and spectroscopy. While these observations have important implications on our understanding of the angular momentum evolution of stars in their late stages of evolution, more direct methods are sorely needed to disentangle ambiguities.

  4. Angular Speed of a Compact Disc

    Science.gov (United States)

    Sawicki, Mikolaj ``Mik''

    2006-09-01

    A spinning motion of a compact disc in a CD player offers an interesting and challenging problem in rotational kinematics with a nonconstant angular acceleration that can be incorporated into a typical introductory physics class for engineers and scientists. It can be used either as an example presented during the lecture, emphasizing application of calculus, or as a homework assignment that could be handled easily with the help of a spreadsheet, thus eliminating the calculus aspect altogether. I tried both approaches, and the spreadsheet study was favored by my students.

  5. Low-dimensional organization of angular momentum during walking on a narrow beam.

    Science.gov (United States)

    Chiovetto, Enrico; Huber, Meghan E; Sternad, Dagmar; Giese, Martin A

    2018-01-08

    Walking on a beam is a challenging motor skill that requires the regulation of upright balance and stability. The difficulty in beam walking results from the reduced base of support compared to that afforded by flat ground. One strategy to maintain stability and hence avoid falling off the beam is to rotate the limb segments to control the body's angular momentum. The aim of this study was to examine the coordination of the angular momentum variations during beam walking. We recorded movement kinematics of participants walking on a narrow beam and computed the angular momentum contributions of the body segments with respect to three different axes. Results showed that, despite considerable variability in the movement kinematics, the angular momentum was characterized by a low-dimensional organization based on a small number of segmental coordination patterns. When the angular momentum was computed with respect to the beam axis, the largest fraction of its variation was accounted for by the trunk segment. This simple organization was robust and invariant across all participants. These findings support the hypothesis that control strategies for complex balancing tasks might be easier to understand by investigating angular momentum instead of the segmental kinematics.

  6. Mid-sagittal plane and mid-sagittal surface optimization in brain MRI using a local symmetry measure

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Skoglund, Karl; Ryberg, Charlotte

    2005-01-01

    , the mid-sagittal plane is not always planar, but a curved surface resulting in poor partitioning of the brain hemispheres. To account for this, this paper also investigates an optimization strategy which fits a thin-plate spline surface to the brain data using a robust least median of squares estimator...

  7. Lengthening osteotomy at the intertrochanteric level with simultaneous correction of angular deformities

    NARCIS (Netherlands)

    Marti, R. K.; ten Holder, E. J.; Kloen, P.

    2001-01-01

    Fixed multiplane deformities around the hip representing a combination of rotational, angular, and leg-length discrepancies are disabling for the patient and pose a challenge for the orthopaedic surgeon. We describe a joint-preserving, one-stage procedure to address these complex problems using an

  8. The influence of molecular rotation on vibration--translation energy transfer

    International Nuclear Information System (INIS)

    McKenzie, R.L.

    1977-01-01

    The role of molecular rotations in the exchange of vibrational and translational energy is investigated for collisions between anharmonic diatomic molecules and structureless atoms. A three-dimensional, semiclassical, impact parameter description is applied with emphasis directed towards the influence of rotational coupling on the net rate of vibrational energy transfer summed over all final rotational states. These results are then related to the predictions of an equivalent collinear collision model, and their comparison allows an evaluation of the collinear approximation. The mechanisms of vibrational energy transfer including rotational transitions are shown to be separable into three classes, with the molecules belonging to each class identified first and foremost by their ratio of fundamental vibrational and rotational frequencies, ω/sub e//B/sub e/, and second by the proximity of their initial state to a near-resonant vibration--rotation transition with a small change in angular momentum. While the dynamics of molecules with ω/sub e//B/sub e/ ratios that are comparable to the range of angular momentum transitions having strong coupling are found to require a complete three-dimensional description, the rates of vibrational energy transfer in molecules with large ω/sub e//B/sub e/ ratios appear to be well approximated by a collinear collision model

  9. Nonlinear Faraday rotation in samarium vapor

    International Nuclear Information System (INIS)

    Barkov, L.M.; Melik-Pashaev, D.A.; Zolotorev, M.S.

    1988-01-01

    Experiments on nonlinear magnetic optical (Faraday) rotation on resonance transitions of atomic samarium are described. Measurements were carried out on transitions with different angular momenta of upper and lower states: 1→0, 0→1 and 1→1. Qualitative explanations of observed phenomena are given

  10. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

    Science.gov (United States)

    Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V.; Ilyushin, V. V.; Alekseev, E. A.; Mescheryakov, A. A.; Hougen, J. T.; Xu, Li-Hong

    2016-07-01

    This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = - 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric "torsionally mediated spin-rotation operators" by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e±niα. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A1 and A2 states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

  11. Rotational dynamics with Tracker

    International Nuclear Information System (INIS)

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

    2012-01-01

    We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia (I) of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction (b) for our system. By omitting the effect of such friction, we derive I for a cylindrical plate rotated around its central axis from the other two experiments based on the relation between torque and angular acceleration of rotational motion and conservation of energy. Movies of the rotating plate and hung masses are recorded. As a result, we have the deviation of I from its theoretical value of 0.4% and 3.3%, respectively. Our setup is completely constructed from locally available inexpensive materials and the experimental results indicate that the system is highly reliable. This work should pave the way for those who prefer to build a similar setup from scratch at relatively low cost compared to commercial units. (paper)

  12. Measuring average angular velocity with a smartphone magnetic field sensor

    Science.gov (United States)

    Pili, Unofre; Violanda, Renante

    2018-02-01

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

  13. The role of spatial memory and frames of reference in the precision of angular path integration.

    Science.gov (United States)

    Arthur, Joeanna C; Philbeck, John W; Kleene, Nicholas J; Chichka, David

    2012-09-01

    Angular path integration refers to the ability to maintain an estimate of self-location after a rotational displacement by integrating internally-generated (idiothetic) self-motion signals over time. Previous work has found that non-sensory inputs, namely spatial memory, can play a powerful role in angular path integration (Arthur et al., 2007, 2009). Here we investigated the conditions under which spatial memory facilitates angular path integration. We hypothesized that the benefit of spatial memory is particularly likely in spatial updating tasks in which one's self-location estimate is referenced to external space. To test this idea, we administered passive, non-visual body rotations (ranging 40°-140°) about the yaw axis and asked participants to use verbal reports or open-loop manual pointing to indicate the magnitude of the rotation. Prior to some trials, previews of the surrounding environment were given. We found that when participants adopted an egocentric frame of reference, the previously-observed benefit of previews on within-subject response precision was not manifested, regardless of whether remembered spatial frameworks were derived from vision or spatial language. We conclude that the powerful effect of spatial memory is dependent on one's frame of reference during self-motion updating. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Rotating solutions in critical Lovelock gravities

    Science.gov (United States)

    Cvetič, M.; Feng, Xing-Hui; Lü, H.; Pope, C. N.

    2017-02-01

    For appropriate choices of the coupling constants, the equations of motion of Lovelock gravities up to order n in the Riemann tensor can be factorized such that the theories admit a single (A)dS vacuum. In this paper we construct two classes of exact rotating metrics in such critical Lovelock gravities of order n in d = 2 n + 1 dimensions. In one class, the n angular momenta in the n orthogonal spatial 2-planes are equal, and hence the metric is of cohomogeneity one. We construct these metrics in a Kerr-Schild form, but they can then be recast in terms of Boyer-Lindquist coordinates. The other class involves metrics with only a single non-vanishing angular momentum. Again we construct them in a Kerr-Schild form, but in this case it does not seem to be possible to recast them in Boyer-Lindquist form. Both classes of solutions have naked curvature singularities, arising because of the over rotation of the configurations.

  15. Rotating solutions in critical Lovelock gravities

    Directory of Open Access Journals (Sweden)

    M. Cvetič

    2017-02-01

    Full Text Available For appropriate choices of the coupling constants, the equations of motion of Lovelock gravities up to order n in the Riemann tensor can be factorized such that the theories admit a single (AdS vacuum. In this paper we construct two classes of exact rotating metrics in such critical Lovelock gravities of order n in d=2n+1 dimensions. In one class, the n angular momenta in the n orthogonal spatial 2-planes are equal, and hence the metric is of cohomogeneity one. We construct these metrics in a Kerr–Schild form, but they can then be recast in terms of Boyer–Lindquist coordinates. The other class involves metrics with only a single non-vanishing angular momentum. Again we construct them in a Kerr–Schild form, but in this case it does not seem to be possible to recast them in Boyer–Lindquist form. Both classes of solutions have naked curvature singularities, arising because of the over rotation of the configurations.

  16. Single rotating stars and the formation of bipolar planetary nebula

    Energy Technology Data Exchange (ETDEWEB)

    García-Segura, G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Km. 103 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico); Villaver, E. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Langer, N. [Argelander-Institut für Astronomie, Universität Bonn, D-53121 Bonn (Germany); Yoon, S.-C. [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of); Manchado, A., E-mail: ggs@astrosen.unam.mx [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38200 La Laguna, Tenerife (Spain)

    2014-03-10

    We have computed new stellar evolution models that include the effects of rotation and magnetic torques under different hypotheses. The goal is to test whether a single star can sustain the rotational velocities needed in the envelope for magnetohydrodynamical(MHD) simulations to shape bipolar planetary nebulae (PNe) when high mass-loss rates take place. Stellar evolution models with main sequence masses of 2.5 and 5 M {sub ☉} and initial rotational velocities of 250 km s{sup –1} have been followed through the PNe formation phase. We find that stellar cores have to be spun down using magnetic torques in order to reproduce the rotation rates observed for white dwarfs. During the asymptotic giant branch phase and beyond, the magnetic braking of the core has a practically null effect on increasing the rotational velocity of the envelope since the stellar angular momentum is efficiently removed by the wind. We have also tested the best possible case scenarios in rather non-physical contexts to give enough angular momentum to the envelope. We find that we cannot get the envelope of a single star to rotate at the speeds needed for MHD simulations to form bipolar PNe. We conclude that single stellar rotators are unlikely to be the progenitors of bipolar PNe under the current MHD model paradigm.

  17. Sagittal synostosis in X-linked hypophosphatemic rickets and related diseases

    Energy Technology Data Exchange (ETDEWEB)

    Currarino, Guido [Texas Scottish Rite Hospital, Department of Radiology, Dallas, TX (United States)

    2007-08-15

    The recent observations of two new cases of X-linked hypophosphatemic rickets associated with premature closure of the sagittal suture prompted a review of similar cases seen in this institution. To review the clinical records and skull radiographs of 28 children with hypophosphatemic rickets in order to investigate the frequency and type of craniosynostosis and other cranial vault changes seen in these conditions and to review the literature for relevant findings. Clinical and imaging records were reviewed on 28 patients with hypophosphatemic rickets, all younger than 18 years. Most patients had X-linked hypophosphatemic rickets and a few had autosomal-dominant hypophosphatemic rickets or were non-familial cases. Of the 28 patients, 13 had sagittal synostosis. Dolichocephaly was present in ten patients. The configuration of the cranial vault in some of these ten patients with dolichocephaly varied somewhat from that seen in nonsyndromic sagittal synostosis. In one patient, a Chiari I malformation was demonstrated by MRI. In another patient with increased intracranial pressure the sagittal suture closure was associated with lambdoidal synostosis. Dolichocephaly was not present in three patients, suggesting that the synostosis started later than in the other patients, probably in the second year of life, a period of slower brain growth than in the first year. The two patients in this group of three showed thickening and sclerosis of the cranial vault of uncertain etiology. There is an increased risk of sagittal synostosis in hypophosphatemic rickets and related diseases in children. The appearance of the cranial vault in this type of synostosis can vary from that seen in nonsyndromic synostosis. In this setting, careful clinical and imaging follow-up is warranted. (orig.)

  18. Sagittal synostosis in X-linked hypophosphatemic rickets and related diseases

    International Nuclear Information System (INIS)

    Currarino, Guido

    2007-01-01

    The recent observations of two new cases of X-linked hypophosphatemic rickets associated with premature closure of the sagittal suture prompted a review of similar cases seen in this institution. To review the clinical records and skull radiographs of 28 children with hypophosphatemic rickets in order to investigate the frequency and type of craniosynostosis and other cranial vault changes seen in these conditions and to review the literature for relevant findings. Clinical and imaging records were reviewed on 28 patients with hypophosphatemic rickets, all younger than 18 years. Most patients had X-linked hypophosphatemic rickets and a few had autosomal-dominant hypophosphatemic rickets or were non-familial cases. Of the 28 patients, 13 had sagittal synostosis. Dolichocephaly was present in ten patients. The configuration of the cranial vault in some of these ten patients with dolichocephaly varied somewhat from that seen in nonsyndromic sagittal synostosis. In one patient, a Chiari I malformation was demonstrated by MRI. In another patient with increased intracranial pressure the sagittal suture closure was associated with lambdoidal synostosis. Dolichocephaly was not present in three patients, suggesting that the synostosis started later than in the other patients, probably in the second year of life, a period of slower brain growth than in the first year. The two patients in this group of three showed thickening and sclerosis of the cranial vault of uncertain etiology. There is an increased risk of sagittal synostosis in hypophosphatemic rickets and related diseases in children. The appearance of the cranial vault in this type of synostosis can vary from that seen in nonsyndromic synostosis. In this setting, careful clinical and imaging follow-up is warranted. (orig.)

  19. Quantization in rotating co-ordinates revisited

    International Nuclear Information System (INIS)

    Hussain, F.; Qadir, A.

    1982-07-01

    Recent work on quantization in rotating co-ordinates showed that no radiation would be seen by an observer rotating with a constant angular speed. This work used a Galilean-type co-ordinate transformation. We show that the same result holds for a Lorentz-type co-ordinate system, in spite of the fact that the metric has a co-ordinate singularity at rΩ = 1. Further, we are able to define positive and negative energy modes for a particular case of a non-static, non-stationary metric. (author)

  20. Counter-rotational effects on stability of 2 + 1-dimensional thin-shell wormholes

    Energy Technology Data Exchange (ETDEWEB)

    Mazharimousavi, S.H.; Halilsoy, M. [Eastern Mediterranean University, Department of Physics, Gazimagusa (Turkey)

    2014-09-15

    The role of angular momentum in a 2 + 1-dimensional rotating thin-shell wormhole (TSW) is considered. Particular emphasis is given to stability when the shells (rings) are counter-rotating. We find that counter-rotating halves make the TSW supported by the equation of state of a linear gas more stable. Under a small velocity dependent perturbation, however, it becomes unstable. (orig.)

  1. Macroscopic description of normal quadrupole oscillations and shape of rotating nuclei (spheroids)

    International Nuclear Information System (INIS)

    Balbutsev, E.B.; Mikhailov, I.N.; Vaishvila, Z.

    1981-01-01

    The ''distorted-Fermi-surface'' model is generalized to study the rotating nuclei. The mathematical problems of the model are solved with the help of the tensor virial method by Chandrasekhar-Lebovitz. The parameters of a form and characteristic frequencies of the quadrupole oscillations are calculated as a function of angular velocity Ω for the rotating nuclei. The energy of Giant Quadrupole Resonance is in agreement with experiment for Ω=0. There are two low-lying modes of oscillations in the model. The critical angular momenta are calculated. The comparison with the liquid drop model is done [ru

  2. Near horizon geometry of rotating black holes in five dimensions

    International Nuclear Information System (INIS)

    Cvetic, M.; Larsen, F.

    1998-01-01

    We interpret the general rotating black holes in five dimensions as rotating black strings in six dimensions. In the near-horizon limit the geometry is locally AdS 3 x S 3 , as in the non-rotating case. However, the global structure couples the AdS 3 and the S 3 , giving angular velocity to the S 3 . The asymptotic geometry is exploited to count the microstates and recover the precise value of the Bekenstein-Hawking entropy, with rotation taken properly into account. We discuss the perturbation spectrum of the rotating black hole, and its relation to the underlying conformal field theory. (orig.)

  3. Comprehensive Analysis of Mandibular Residual Asymmetry after Bilateral Sagittal Split Ramus Osteotomy Correction of Menton Point Deviation.

    Science.gov (United States)

    Lin, Han; Zhu, Ping; Lin, Qiuping; Huang, Xiaoqiong; Xu, Yue; Yang, Xiaoping

    2016-01-01

    Facial asymmetry often persists even after mandibular deviation corrected by the bilateral sagittal split ramus osteotomy (BSSRO) operation, since the reference facial sagittal plane for the asymmetry analysis is usually set up before the mandibular menton (Me) point correction. Our aim is to develop a predictive and quantitative method to assess the true asymmetry of the mandible after a midline correction performed by a virtual BSSRO, and to verify its availability by evaluation of the post-surgical improvement. A retrospective cohort study was conducted at the Hospital of Stomatology, Sun Yat-sen University (China) of patients with pure hemi-mandibular elongation (HE) from September 2010 through May 2014. Mandibular models were reconstructed from CBCT images of patients with pre-surgical orthodontic treatment. After mandibular de-rotation and midline alignment with virtual BSSRO, the elongation hemi-mandible was virtually mirrored along the facial sagittal plane. The residual asymmetry, defined as the superimposition and boolean operation of the mirrored elongation side on the normal side, was calculated, including the volumetric differences and the length of transversal and vertical asymmetry discrepancy. For more specific evaluation, both sides of the hemi-mandible were divided into the symphysis and parasymphysis (SP), mandibular body (MB), and mandibular angle (MA) regions. Other clinical variables include deviation of Me point, dental midline and molar relationship. The measurement of volumetric discrepancy between the two sides of post-surgical hemi-mandible were also calculated to verify the availability of virtual surgery. Paired t-tests were computed and the P value was set at .05. This study included 45 patients. The volume differences were 407.8±64.8 mm3, 2139.1±72.5 mm3, and 422.5±36.9 mm3; residual average transversal discrepancy, 1.9 mm, 1.0 mm, and 2.2 mm; average vertical discrepancy, 1.1 mm, 2.2 mm, and 2.2 mm (before virtual surgery). The

  4. On the Terminal Rotation Rates of Giant Planets

    Science.gov (United States)

    Batygin, Konstantin

    2018-04-01

    Within the general framework of the core-nucleated accretion theory of giant planet formation, the conglomeration of massive gaseous envelopes is facilitated by a transient period of rapid accumulation of nebular material. While the concurrent build-up of angular momentum is expected to leave newly formed planets spinning at near-breakup velocities, Jupiter and Saturn, as well as super-Jovian long-period extrasolar planets, are observed to rotate well below criticality. In this work, we demonstrate that the large luminosity of a young giant planet simultaneously leads to the generation of a strong planetary magnetic field, as well as thermal ionization of the circumplanetary disk. The ensuing magnetic coupling between the planetary interior and the quasi-Keplerian motion of the disk results in efficient braking of planetary rotation, with hydrodynamic circulation of gas within the Hill sphere playing the key role of expelling spin angular momentum to the circumstellar nebula. Our results place early-stage giant planet and stellar rotation within the same evolutionary framework, and motivate further exploration of magnetohydrodynamic phenomena in the context of the final stages of giant planet formation.

  5. Large scale circulation in the convection zone and solar differential rotation

    Energy Technology Data Exchange (ETDEWEB)

    Belvedere, G [Instituto di Astronomia dell' Universita di Catania, 95125 Italy; Paterno, L [Osservatorio Astrofisico di Catania, 95125 Italy

    1976-04-01

    In this paper the dependence on depth and latitude of the solar angular velocity produced by a meridian circulation in the convection zone is studied assuming that the main mechanism responsible for setting up and driving the circulation is the interaction of rotation with convection. The first order equations (perturbation of the spherically symmetric state are solved in the Boussinesq approximation and in the steady state for the axissymmetric case. The interaction of convection with rotation is modelled by a convective transport coefficient. The model is consistent with the fact that the interaction of convection with rotation sets up a circulation (driven by the temperature gradient) which carries angular momentum toward the equator against the viscous friction. Unfortunately also a large flux variation at the surface is obtained. Nevertheless it seems that the model has the basic requisites for correct dynamo action.

  6. Coherent spin-rotational dynamics of oxygen superrotors

    Science.gov (United States)

    Milner, Alexander A.; Korobenko, Aleksey; Milner, Valery

    2014-09-01

    We use state- and time-resolved coherent Raman spectroscopy to study the rotational dynamics of oxygen molecules in ultra-high rotational states. While it is possible to reach rotational quantum numbers up to N≈ 50 by increasing the gas temperature to 1500 K, low population levels and gas densities result in correspondingly weak optical response. By spinning {{O}2} molecules with an optical centrifuge, we efficiently excite extreme rotational states with N≤slant 109 in high-density room temperature ensembles. Fast molecular rotation results in the enhanced robustness of the created rotational wave packets against collisions, enabling us to observe the effects of weak spin-rotation coupling in the coherent rotational dynamics of oxygen. The decay rate of spin-rotational coherence due to collisions is measured as a function of the molecular angular momentum and its dependence on the collisional adiabaticity parameter is discussed. We find that at high values of N, the rotational decoherence of oxygen is much faster than that of the previously studied non-magnetic nitrogen molecules, pointing at the effects of spin relaxation in paramagnetic gases.

  7. Generation and sustainment of plasma rotation by ICRF heating

    International Nuclear Information System (INIS)

    Perkins, F.W.; White, R.; Bonoli, P.T.; Chan, V.S.

    2001-01-01

    A mechanism is proposed and evaluated for driving rotation in tokamak plasmas by minority ion-cyclotron heating, even though this process introduces negligible angular momentum. The mechanism has two elements: First, angular momentum transport is governed by a diffusion equation with a non-slip boundary condition at the separatrix. Second, Monte-Carlo calculations show that energized particles will provide a torque density source which has a zero volume integral but separated positive and negative regions. With such a source, a solution of the diffusion equation predicts the on-axis rotation frequency Ω to be Ω=(4q max WJ*)eBR 3 a 2 n e (2π) 2 ) -1 (τ M /τ E ) where vertical bar J* vertical bar ∼ 5-10 is a non-dimensional rotation frequency calculated by the Monte-Carlo ORBIT code. Overall, agreement with experiment is good, when the resonance is on the low-field-side of the magnetic axis. The rotation becomes more counter-current and reverses sign on the high field side for a no-slip boundary. The velocity shear layer position is controllable and of sufficient magnitude to affect microinstabilities. (author)

  8. The elastic transfer model of angular rate modulation in F1-ATPase stalling and controlled rotation experiments

    Science.gov (United States)

    Volkán-Kacsó, S.

    2017-06-01

    The recent experimental, theoretical and computational advances in the field of F1-ATPase single-molecule microscopy are briefly surveyed. The role of theory is revealed in the statistical analysis, interpretation and prediction of single-molecule experimental trajectories, and in linking them with atomistic simulations. In particular, a theoretical model of elastically coupled molecular group transfer is reviewed and a detailed method for its application in stalling and controlled rotation experiments is provided. It is shown how the model can predict, using previous experiments, the rates of ligand binding/release processes (steps) and their exponential dependence on rotor angle in these experiments. The concept of Brønsted slopes is reviewed in the context of the single-molecule experiments, and the rate versus rotor angle relations are explained using the elastic model. These experimental data are treated in terms of the effect of thermodynamic driving forces on the rates assuming that the rotor shaft is elastically coupled to stator ring subunits in which the steps occur. In the application of the group transfer model on an extended angular range processes leading up to the transfer are discussed. Implications for large-scale atomistic simulation are suggested for the treatment of torque-generating steps.

  9. Sagittal synostosis: I. Preoperative morphology of the skull

    DEFF Research Database (Denmark)

    Guimaraes-Ferreira, J.; Gewalli, F.; David, L.

    2006-01-01

    The aim of this study was to characterise the preoperative morphology of the skull in sagittal synostosis in an objective and quantified way. The shapes of the skulls of 105 patients with isolated premature synostosis of the sagittal suture ( SS group) were studied and compared with those......, skull base, and orbit ( 42 in the lateral and 46 in the frontal projections), the production of plots of mean shape for each group, and the intergroup comparison of a series of 81 variables ( linear distance between selected landmarks, and angles defined by groups of three landmarks). Data from...... skull width. Comparison of the mean values of an SS subgroup to age-matched normative data showed a longer (p differ significantly...

  10. Units of rotational information

    Science.gov (United States)

    Yang, Yuxiang; Chiribella, Giulio; Hu, Qinheping

    2017-12-01

    Entanglement in angular momentum degrees of freedom is a precious resource for quantum metrology and control. Here we study the conversions of this resource, focusing on Bell pairs of spin-J particles, where one particle is used to probe unknown rotations and the other particle is used as reference. When a large number of pairs are given, we show that every rotated spin-J Bell state can be reversibly converted into an equivalent number of rotated spin one-half Bell states, at a rate determined by the quantum Fisher information. This result provides the foundation for the definition of an elementary unit of information about rotations in space, which we call the Cartesian refbit. In the finite copy scenario, we design machines that approximately break down Bell states of higher spins into Cartesian refbits, as well as machines that approximately implement the inverse process. In addition, we establish a quantitative link between the conversion of Bell states and the simulation of unitary gates, showing that the fidelity of probabilistic state conversion provides upper and lower bounds on the fidelity of deterministic gate simulation. The result holds not only for rotation gates, but also to all sets of gates that form finite-dimensional representations of compact groups. For rotation gates, we show how rotations on a system of given spin can simulate rotations on a system of different spin.

  11. Training intensity and sagittal curvature of the spine in male and female artistic gymnasts.

    Science.gov (United States)

    Sanz-Mengibar, Jose M; Sainz-de-Baranda, Pilar; Santonja-Medina, Fernando

    2018-04-01

    Specific adaptations of the spine in the sagittal plane have been described according to different sports disciplines. The goal of this study was to describe the integrative diagnosis of the sagittal morphotype of the spine in male and female artistic gymnasts. Forty-eight gymnasts were measured with an inclinometer. Thoracic and lumbar curves were quantified in standing position, in Sit and Reach and Slump Sitting in order to assess the sagittal spine posture and analyze if adaptations were related to training intensity. Correlation values of the sagittal plane spine measurements showed significantly increased thoracic kyphosis in men (-0.445, Partistic gymnastics; however, this sport seems to cause specific adaptations in postural hypolordosis, functional thoracic kyphosis and lumbar kyphotic attitude during sitting and trunk flexion. The implications of the functional adaptations observed in our results may require a preventive intervention in male and female artistic gymnasts can be assessed with the integrative diagnosis of the sagittal morphotype of the spine.

  12. Sagittal imbalance in patients with lumbar spinal stenosis and outcomes after simple decompression surgery.

    Science.gov (United States)

    Shin, E Kyung; Kim, Chi Heon; Chung, Chun Kee; Choi, Yunhee; Yim, Dahae; Jung, Whei; Park, Sung Bae; Moon, Jung Hyeon; Heo, Won; Kim, Sung-Mi

    2017-02-01

    Lumbar spinal stenosis (LSS) is the most common lumbar degenerative disease, and sagittal imbalance is uncommon. Forward-bending posture, which is primarily caused by buckling of the ligamentum flavum, may be improved via simple decompression surgery. The objectives of this study were to identify the risk factors for sagittal imbalance and to describe the outcomes of simple decompression surgery. This is a retrospective nested case-control study PATIENT SAMPLE: This was a retrospective study that included 83 consecutive patients (M:F=46:37; mean age, 68.5±7.7 years) who underwent decompression surgery and a minimum of 12 months of follow-up. The primary end point was normalization of sagittal imbalance after decompression surgery. Sagittal imbalance was defined as a C7 sagittal vertical axis (SVA) ≥40 mm on a 36-inch-long lateral whole spine radiograph. Logistic regression analysis was used to identify the risk factors for sagittal imbalance. Bilateral decompression was performed via a unilateral approach with a tubular retractor. The SVA was measured on serial radiographs performed 1, 3, 6, and 12 months postoperatively. The prognostic factors for sagittal balance recovery were determined based on various clinical and radiological parameters. Sagittal imbalance was observed in 54% (45/83) of patients, and its risk factors were old age and a large mismatch between pelvic incidence and lumbar lordosis. The 1-year normalization rate was 73% after decompression surgery, and the median time to normalization was 1 to 3 months. Patients who did not experience SVA normalization exhibited low thoracic kyphosis (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02-1.10) (pimbalance was observed in more than 50% of LSS patients, but this imbalance was correctable via simple decompression surgery in 70% of patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Critical gravitational collapse with angular momentum. II. Soft equations of state

    Science.gov (United States)

    Gundlach, Carsten; Baumgarte, Thomas W.

    2018-03-01

    We study critical phenomena in the collapse of rotating ultrarelativistic perfect fluids, in which the pressure P is related to the total energy density ρ by P =κ ρ , where κ is a constant. We generalize earlier results for radiation fluids with κ =1 /3 to other values of κ , focusing on κ power-law scalings of the black-hole mass. We do see systematic effects in the black-hole angular momentum, but it is not clear yet if these are due to the predicted nontrivial scaling functions, or to nonlinear effects at sufficiently large initial angular momentum (which we do not account for in our theoretical model).

  14. Angular dependence of Auger signals from a GaAs (111) surface

    International Nuclear Information System (INIS)

    Barnard, W.O.

    1984-03-01

    This dissertation is concerned with the angular dependence of the L 3 M 4 M 4 1067 eV Ga and L 3 M 4 M 4 1228 eV As Auger electron signals from a (111) GaAs surface, using a system which is equipped with a cylindrical mirror analyser. Following a detailed discussion of the Auger process, a review is given of angular effects in the emission excitation and detection of Auger signals. Present theories are discussed and an empirical theory is developed to test the experimental results obtained in this study. The experimental procedures and equipment used are presented. It was found that the Auger signals show a strong variation with the angle of rotation about the normal of a GaAs surface. Furthermore, the nature of the angular spectra of the Ga and As signals are interchanged when the electron beam incident surface is changed from (111) to (111). The main features of the angular variation of the quasi-elastic backscattered signal is reflected in the corresponding Ga and As Auger angular spectra. The angular dependence of the quasi-elastic backscattered signal can be explained semi-quantitatively in terms of the empirical theory. Theoretical arguments are presented which suggest that the Auger signals should show an angular dependence similar to the quasi-elastic backscattered signal. Evidence was found that geometric screening-off of underlying atoms by surface and near surface atoms influence the Auger yield

  15. Viscous damping of toroidal angular momentum in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M. [Georgia Tech Fusion Research Center, Atlanta, Georgia 30332 (United States)

    2014-09-15

    The Braginskii viscous stress tensor formalism was generalized to accommodate non-axisymmetric 3D magnetic fields in general toroidal flux surface geometry in order to provide a representation for the viscous damping of toroidal rotation in tokamaks arising from various “neoclassical toroidal viscosity” mechanisms. In the process, it was verified that the parallel viscosity contribution to damping toroidal angular momentum still vanishes even in the presence of toroidal asymmetries, unless there are 3D radial magnetic fields.

  16. Raynal–Revai coefficients for a general kinematic rotation

    International Nuclear Information System (INIS)

    Ershov, S. N.

    2016-01-01

    In a three-body system, transitions between different sets of normalized Jacobi coordinates are described as general kinematic transformations that include an orthogonal or a pseudoorthogonal rotation. For such rotations, the Raynal–Revai coefficients execute a unitary transformation between three-body hyperspherical functions. Recurrence relations that make it possible to calculate the Raynal–Revai coefficients for arbitrary angular momenta are derived on the basis of linearized representations of products of hyperspherical functions.

  17. Elastic-plastic transition on rotating spherical shells in dependence of compressibility

    Directory of Open Access Journals (Sweden)

    Thakur Pankaj

    2017-01-01

    Full Text Available The purpose of this paper is to establish the mathematical model on the elastic-plastic transitions occurring in the rotating spherical shells based on compressibility of materials. The paper investigates the elastic-plastic stresses and angular speed required to start yielding in rotating shells for compressible and incompressible materials. The paper is based on the non-linear transition theory of elastic-plastic shells given by B.R. Seth. The elastic-plastic transition obtained is treated as an asymptotic phenomenon at critical points & the solution obtained at these points generates stresses. The solution obtained does not require the use of semi-empirical yield condition like Tresca or Von Mises or other certain laws. Results are obtained numerically and depicted graphically. It has been observed that Rotating shells made of the incompressible material are on the safer side of the design as compared to rotating shells made of compressible material. The effect of density variation has been discussed numerically on the stresses. With the effect of density variation parameter, rotating spherical shells start yielding at the internal surface with the lower values of the angular speed for incompressible/compressible materials.

  18. Angular momentum transport by tidal acoustic wave

    International Nuclear Information System (INIS)

    Sakurai, T.

    1976-01-01

    An analytical expression of the braking torque on a Jacobian ellipsoid rotating steadily in an enviromental gas is given, based on the assumption that the ellipsoid rotates around its shortest principal axis with an angular momentum slightly larger than that at the bifurcation point of the Maclaurin spheroid. This braking torque is effected by the gravitational interaction between the ellipsoid matter and a spiral density configuration in the environmental gas. This spiral configuration which is called a tidal acoustic wave, is caused by the zone of silence effect in a supersonic flow. With respect to a coordinates system rotating with the ellipsoid, a supersonic region appears outside a certain radius. In this supersonic region, the effect of the non-axisymmetric fluctuation in the ellipsoid potential propagates along the downstream branches of the Mach waves. This one-sided response of the supersonic part causes the tidal acoustic wave. The discussion is restricted to the equatorial plane, and an acoustic approximation of the basic equations is used under the assumption that the self-gravity effect of the environmental gas is negligable in comparison to the main gravity of the ellipsoid. The results are applied to the pre- and post-Main sequence phases of a rotating star, and relating astrophysical problems are discussed. (Auth.)

  19. Angular momentum transport by tidal acoustic wave

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, T [Kyoto Univ. (Japan). Faculty of Engineering

    1976-05-01

    An analytical expression of the braking torque on a Jacobian ellipsoid rotating steadily in an enviromental gas is given, based on the assumption that the ellipsoid rotates around its shortest principal axis with an angular momentum slightly larger than that at the bifurcation point of the Maclaurin spheroid. This braking torque is effected by the gravitational interaction between the ellipsoid matter and a spiral density configuration in the environmental gas. This spiral configuration which is called a tidal acoustic wave, is caused by the zone of silence effect in a supersonic flow. With respect to a coordinates system rotating with the ellipsoid, a supersonic region appears outside a certain radius. In this supersonic region, the effect of the non-axisymmetric fluctuation in the ellipsoid potential propagates along the downstream branches of the Mach waves. This one-sided response of the supersonic part causes the tidal acoustic wave. The discussion is restricted to the equatorial plane, and an acoustic approximation of the basic equations is used under the assumption that the self-gravity effect of the environmental gas is negligable in comparison to the main gravity of the ellipsoid. The results are applied to the pre- and post-Main sequence phases of a rotating star, and relating astrophysical problems are discussed.

  20. The Influence of Natural Head Position on the Cervical Sagittal Alignment

    Directory of Open Access Journals (Sweden)

    Kuan Wang

    2017-01-01

    Full Text Available Introduction. This study investigated the relationship between the parameters related to the natural head position and cervical segmental angles and alignment of patients with neck pain. Material and Methods. The lateral radiographs of the cervical spine were collected from 103 patients and were used to retrospectively analyze the correlation between the natural head position, cervical local sagittal angles, and alignment. Sagittal measurements were as follows: cervical curvature classification, slope of McGregor’s line (McGS, local sagittal angles (C0–C2 angle, C2–C5 angle, C5–C7 angle, and C2–C7 angle, T1 slope, center of gravity of the head to sagittal vertical axis (CG–C7 SVA, and local sagittal alignment (C0–C2 SVA and C2–C7 SVA. Results. McGS was significantly correlated to C0–C2 angle (r=0.57, C0–C2 SVA (r=−0.53, C2–C7 SVA (r=−0.28, and CG–C7 SVA (r=−0.47. CG–C7 SVA was also significantly correlated to curvature type (r=0.27, C5–C7 angle (r=−0.37, and C2–C7 angle (r=−0.39. Conclusions. A backward shift with an extended head position may accompany a relatively normal curvature of the cervical spine. The effect of posture control in relieving abnormal mechanical state of the cervical spine needs to be further confirmed by biomechanical analysis.

  1. Nuclear level density parameter 's dependence on angular momentum

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Kailas, S.

    2009-01-01

    Nuclear level densities represent a very important ingredient in the statistical Model calculations of nuclear reaction cross sections and help to understand the microscopic features of the excited nuclei. Most of the earlier experimental nuclear level density measurements are confined to low excitation energy and low spin region. A recent experimental investigation of nuclear level densities in high excitation energy and angular momentum domain with some interesting results on inverse level density parameter's dependence on angular momentum in the region around Z=50 has motivated us to study and analyse these experimental results in a microscopic theoretical framework. In the experiment, heavy ion fusion reactions are used to populate the excited and rotating nuclei and measured the α particle evaporation spectra in coincidence with ray multiplicity. Residual nuclei are in the range of Z R 48-55 with excitation energy range 30 to 40 MeV and angular momentum in 10 to 25. The inverse level density parameter K is found to be in the range of 9.0 - 10.5 with some exceptions

  2. Angular momentum transport in accretion disk boundary layers around weakly magnetized stars

    DEFF Research Database (Denmark)

    Pessah, M.E.; Chan, C.-K.

    2013-01-01

    ) is inefficient in disk regions where, as expected in boundary layers, the angular frequency increases with radius. Motivated by the need of a deeper understanding of the behavior of an MHD fluid in a differentially rotating background that deviates from a Keplerian profile, we study the dynamics of MHD waves...

  3. Locking of intrinsic angular momentum in collision complexes

    International Nuclear Information System (INIS)

    Berengolts, Alexander.

    1995-04-01

    A concept of locking of the intrinsic angular momentum of a fragment of a collision complex to a body-fixed axis is widely used in the description of heavy-particle dynamics. The aim of this work is to provide a semiclassical description of the locking phenomenon which occur in diatomic and three atomic collision complexes. The first part of this work is devoted to the semiclassical study of the locking of the electronic angular momentum that occurs in slow collisions of two atoms, one in the spherically symmetric state and the other in state with j= 1. Here we calculate explicitly the complete locking matrix for different types of interatomic interactions. The elements of this matrix directly enter into the semiclassical expression for the different cross sections of polarized atoms. Limitations to the notion of the the locking radius and slipping probability are discussed in connection with the steepness of the interaction. Numerical calculations confirm analytical result: the optimal criterion for determination of the locking radius is a condition for the accumulated phase difference between two molecular states. Analytical expressions are suggested for the locking angle and the slipping probability. Implication of the locking approximation for calculation of the quasiclassical scattering matrix is discussed. The second part considers the locking of the rotational angular momentum of a diatom in the decomposition of a triatomic complexes. We discuss here cases J = 1,2,3 and 4, but restrict ourselves to calculation of the so-called dynamic orientation of the diatomic fragment. The letter represents one of the characteristics of the locking matrix which in principle can be measured experimentally. The orientation is created as a result of the interplay between the adiabatic interaction in the atom- diatom exit channel and the rotationally non adiabatic coupling in the perturbed rotor region

  4. Nuclear structure at high angular momentum

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1976-08-01

    There is considerable interest in high angular-momentum states of nuclei, and some recent progress in three areas is discussed. Part I considers transitional nuclei, where two types of rotational bands--decoupled and strongly coupled--are found to occur very frequently. These can be described by several collective models, but the required potential-energy surfaces seem to differ somewhat from those calculated microscopically. In Part II the processes that might cause backbending (irregularities in the rotational levels of certain nuclei) are discussed, and alignment of individual nucleons now seems to be the cause in most cases. The mixing of the ground band with this aligned band can be studied in some detail using Coulomb excitation with very heavy ions. Part III deals with the very high-spin states where effective moments of inertia have been obtained for spins up to 50h. Also structure has been seen in the spectra around these spin values which can be tentatively related to calculated shell effects. 74 references, 61 figures

  5. Interacting fermions in rotation: chiral symmetry restoration, moment of inertia and thermodynamics

    International Nuclear Information System (INIS)

    Chernodub, M.N.; Gongyo, Shinya

    2017-01-01

    We study rotating fermionic matter at finite temperature in the framework of the Nambu-Jona-Lasinio model. In order to respect causality the rigidly rotating system must be bound by a cylindrical boundary with appropriate boundary conditions that confine the fermions inside the cylinder. We show the finite geometry with the MIT boundary conditions affects strongly the phase structure of the model leading to three distinct regions characterized by explicitly broken (gapped), partially restored (nearly gapless) and spontaneously broken (gapped) phases at, respectively, small, moderate and large radius of the cylinder. The presence of the boundary leads to specific steplike irregularities of the chiral condensate as functions of coupling constant, temperature and angular frequency. These steplike features have the same nature as the Shubnikov-de Haas oscillations with the crucial difference that they occur in the absence of both external magnetic field and Fermi surface. At finite temperature the rotation leads to restoration of spontaneously broken chiral symmetry while the vacuum at zero temperature is insensitive to rotation (“cold vacuum cannot rotate”). As the temperature increases the critical angular frequency decreases and the transition becomes softer. A phase diagram in angular frequency-temperature plane is presented. We also show that at fixed temperature the fermion matter in the chirally restored (gapless) phase has a higher moment of inertia compared to the one in the chirally broken (gapped) phase.

  6. Interacting fermions in rotation: chiral symmetry restoration, moment of inertia and thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chernodub, M.N. [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université de Tours,Tours (France); Laboratory of Physics of Living Matter, Far Eastern Federal University,Vladivostok (Russian Federation); Gongyo, Shinya [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université de Tours,Tours (France); Theoretical Research Division, Nishina Center, RIKEN,Saitama (Japan)

    2017-01-30

    We study rotating fermionic matter at finite temperature in the framework of the Nambu-Jona-Lasinio model. In order to respect causality the rigidly rotating system must be bound by a cylindrical boundary with appropriate boundary conditions that confine the fermions inside the cylinder. We show the finite geometry with the MIT boundary conditions affects strongly the phase structure of the model leading to three distinct regions characterized by explicitly broken (gapped), partially restored (nearly gapless) and spontaneously broken (gapped) phases at, respectively, small, moderate and large radius of the cylinder. The presence of the boundary leads to specific steplike irregularities of the chiral condensate as functions of coupling constant, temperature and angular frequency. These steplike features have the same nature as the Shubnikov-de Haas oscillations with the crucial difference that they occur in the absence of both external magnetic field and Fermi surface. At finite temperature the rotation leads to restoration of spontaneously broken chiral symmetry while the vacuum at zero temperature is insensitive to rotation (“cold vacuum cannot rotate”). As the temperature increases the critical angular frequency decreases and the transition becomes softer. A phase diagram in angular frequency-temperature plane is presented. We also show that at fixed temperature the fermion matter in the chirally restored (gapless) phase has a higher moment of inertia compared to the one in the chirally broken (gapped) phase.

  7. The structure of rotational discontinuities

    International Nuclear Information System (INIS)

    Neugebauer, M.

    1989-01-01

    This study examines the structures of a set of rotational discontinuities detected in the solar wind by the ISEE-3 spacecraft. It is found that the complexity of the structure increases as the angle θ between the propagation vector k and the magnetic field decreases. For rotational discontinuities that propagate at a large angle to the field with an ion (left-hand) sense of rotation, the magnetic hodograms tend to be flattened, in agreement with prior numerical simulations. When θ is large, angular overshoots are often observed at one or both ends of the discontinuity. When the propagation is nearly parallel to the field (i.e., when θ is small), many different types of structure are seen, ranging from straight lines, the S-shaped curves, to complex, disorganized shapes

  8. The interference effects of non-rotated versus counter-rotated trials in visuomotor adaptation.

    Science.gov (United States)

    Hinder, Mark R; Walk, Laura; Woolley, Daniel G; Riek, Stephan; Carson, Richard G

    2007-07-01

    An isometric torque-production task was used to investigate interference and retention in adaptation to multiple visuomotor environments. Subjects produced isometric flexion-extension and pronation-supination elbow torques to move a cursor to acquire targets as quickly as possible. Adaptation to a 30 degrees counter-clockwise (CCW) rotation (task A), was followed by a period of rest (control), trials with no rotation (task B0), or trials with a 60 degrees clockwise (CW) rotation (task B60). For all groups, retention of task A was assessed 5 h later. With initial training, all groups reduced the angular deviation of cursor paths early in the movements, indicating feedforward adaptation. For the control group, performance at commencement of the retest was significantly better than that at the beginning of the initial learning. For the B0 group, performance in the retest of task A was not dissimilar to that at the start of the initial learning, while for the B60 group retest performance in task A was markedly worse than initially observed. Our results indicate that close juxtaposition of two visuomotor environments precludes improved retest performance in the initial environment. Data for the B60 group, specifically larger angular errors upon retest compared with initial exposures, are consistent with the presence of anterograde interference. Furthermore, full interference occurred even when the visuomotor environment encountered in the second task was not rotated (B0). This latter novel result differs from those obtained for force field learning, where interference does not occur when task B does not impose perturbing forces, i.e., when B consists of a null field (Brashers-Krug et al., Nature 382:252-255, 1996). The results are consistent with recent proposals suggesting different interference mechanisms for visuomotor (kinematic) compared to force field (dynamic) adaptations, and have implications for the use of washout trials when studying interference between

  9. Sagittal lumbar and pelvic alignment in the standing and sitting positions.

    Science.gov (United States)

    Endo, Kenji; Suzuki, Hidekazu; Nishimura, Hirosuke; Tanaka, Hidetoshi; Shishido, Takaaki; Yamamoto, Kengo

    2012-11-01

    The sitting position has become the most common posture in today's workplace. In relation to this position, kinematic analysis of the lumbar spine is helpful in understanding the causes of low back pain and its prevention. In this study, we investigated the relationship between sagittal lumbar alignment and pelvic alignment in the standing and sitting positions for 50 healthy adults. Lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured on lateral lumbar spine standing and sitting radiographs. Regarding changes from the standing to sitting positions, average LLA, SS, and PT were -16.6° (-49.8 %), -18.7° (-50.3 %), and 18.3° (284.8 %), respectively (P position, lumbar lordosis was reduced and pelvic rotation became posterior. This study showed that LLA decreased by approximately 50 % and PT increased by approximately 25 % in the sitting position compared with the standing position. No significant gender differences were observed for LLA, SS, and PT in the standing position. In the sitting position, however, LLA and SS were markedly larger for women.

  10. Do axes of rotation change during fast and slow motions of the dominant and non-dominate arms?

    Directory of Open Access Journals (Sweden)

    Pagano Christopher

    2011-12-01

    Full Text Available The velocity-dependent change in rotational axes observed in the control of unconstrained 3D arm rotations for the dominant limb seems to conform to a minimum inertia resistance (MIR principle [4]. This is an efficient biomechanical solution that allows for the reduction of torques. We tested whether the MIR principle governs rotating movement when subjects were instructed to maintain the shoulder-elbow joint axis close to horizontal for both dominant and non dominant limbs. Subjects (n=12 performed externalinternal rotations of their arms in two angular positions (90° versus 150°, two angular velocities (slow (S versus fast (F, and in two sensory conditions (kinaesthetic (K versus visuo- kinaesthetic (VK. We expected more scattered displacements of the rotation axis employed for rotating the non dominant limb compared to the dominant limb. The results showed that the rotational axis of a multiarticulated limb coincided with SH-EL at S & F velocity for both arms.

  11. Surface geometry of a rotating black hole in a magnetic field

    International Nuclear Information System (INIS)

    Kulkarni, R.; Dadhich, N.

    1986-01-01

    We study the intrinsic geometry of the surface of a rotating black hole in a uniform magnetic field, using a metric discovered by Ernst and Wild. Rotating black holes are analogous to material rotating bodies according to Smarr since black holes also tend to become more oblate on being spun up. Our study shows that the presence of a strong magnetic field ensures that a black hole actually becomes increasingly prolate on being spun up. Studying the intrinsic geometry of the black-hole surface also gives rise to an interesting embedding problem. Smarr shows that a Kerr black hole cannot be globally isometrically embedded in R 3 if its specific angular momentum a exceeds (√3 /2)mapprox.0.866. . .m. We show that in the presence of a magnetic field of strength B, satisfying 2- √3 2 m 2 3 for all values of the angular momentum

  12. Growth of black holes in the interior of rotating neutron stars

    DEFF Research Database (Denmark)

    Kouvaris, C.; Tinyakov, P.

    2014-01-01

    Mini-black holes made of dark matter that can potentially form in the interior of neutron stars always have been thought to grow by accreting the matter of the core of the star via a spherical Bondi accretion. However, neutron stars have sometimes significant angular velocities that can...... in principle stall the spherical accretion and potentially change the conclusions derived about the time it takes for black holes to destroy a star. We study the effect of the star rotation on the growth of such black holes and the evolution of the black hole spin. Assuming no mechanisms of angular momentum...... evacuation, we find that even moderate rotation rates can in fact destroy spherical accretion at the early stages of the black hole growth. However, we demonstrate that the viscosity of nuclear matter can alleviate the effect of rotation, making it possible for the black hole to maintain spherical accretion...

  13. Sagittal alignment after single cervical disc arthroplasty.

    Science.gov (United States)

    Guérin, Patrick; Obeid, Ibrahim; Gille, Olivier; Bourghli, Anouar; Luc, Stéphane; Pointillart, Vincent; Vital, Jean-Marc

    2012-02-01

    Prospective study. To analyze the sagittal balance after single-level cervical disc replacement (CDR) and range of motion (ROM). To define clinical and radiologic parameters those have a significant correlation with segmental and overall cervical curvature after CDR. Clinical outcomes and ROM after CDR with Mobi-C (LDR, Troyes, France) prosthesis have been documented in few studies. No earlier report of this prosthesis has studied correlations between static and dynamic parameters or those between static parameters and clinical outcomes. Forty patients were evaluated. Clinical outcome was assessed using the Short Form-36 questionnaire, Neck Disability Index, and a Visual Analog Scale. Spineview software (Surgiview, Paris, France) was used to investigate sagittal balance parameters and ROM. The mean follow-up was 24.3 months (range: 12 to 36 mo). Clinical outcomes were satisfactory. There was a significant improvement of Short Form-36, Neck Disability Index, and Visual Analog Scale scores. Mean ROM was 8.3 degrees preoperatively and 11.0 degrees postoperatively (P=0.013). Mean preoperative C2C7 curvature was 12.8 and 16.0 degrees at last follow-up (P=0.001). Mean preoperative functional spinal unit (FSU) angle was 2.3 and 5.3 degrees postoperatively (P<0.0001). Mean postoperative shell angle was 5.5 degrees. There was a significant correlation between postoperative C2C7 alignment and preoperative C2C7 alignment, change of C2C7 alignment, preoperative and postoperative FSU angle, and prosthesis shell angle. There was also a significant correlation between postoperative FSU angle and preoperative C2C7 alignment, preoperative FSU angle, change of FSU angle, and prosthesis shell angle. Regression analysis showed that prosthesis shell angle and preoperative FSU angle contributed significantly to postoperative FSU angle. Moreover, preoperative C2C7 alignment, preoperative FSU angle, postoperative FSU angle, and prosthesis shell angle contributed significantly to

  14. Effect of rotating electric field on 3D complex (dusty) plasma

    Science.gov (United States)

    Wörner, L.; Nosenko, V.; Ivlev, A. V.; Zhdanov, S. K.; Thomas, H. M.; Morfill, G. E.; Kroll, M.; Schablinski, J.; Block, D.

    2011-06-01

    The effect of rotating electric field on 3D particle clusters suspended in rf plasma was studied experimentally. Spheroidal clusters were suspended inside a glass box mounted on the lower horizontal rf electrode, with gravity partially balanced by thermophoretic force. Clusters rotated in the horizontal plane, in response to rotating electric field that was created inside the box using conducting coating on its inner surfaces ("rotating wall" technique). Cluster rotation was always in the direction of applied field and had a shear in the vertical direction. The angular speed of rotation was 104-107 times lower than applied frequency. The experiment is compared to a recent theory.

  15. Rotating quantum Gaussian packets

    International Nuclear Information System (INIS)

    Dodonov, V V

    2015-01-01

    We study two-dimensional quantum Gaussian packets with a fixed value of mean angular momentum. This value is the sum of two independent parts: the ‘external’ momentum related to the motion of the packet center and the ‘internal’ momentum due to quantum fluctuations. The packets minimizing the mean energy of an isotropic oscillator with the fixed mean angular momentum are found. They exist for ‘co-rotating’ external and internal motions, and they have nonzero correlation coefficients between coordinates and momenta, together with some (moderate) amount of quadrature squeezing. Variances of angular momentum and energy are calculated, too. Differences in the behavior of ‘co-rotating’ and ‘anti-rotating’ packets are shown. The time evolution of rotating Gaussian packets is analyzed, including the cases of a charge in a homogeneous magnetic field and a free particle. In the latter case, the effect of initial shrinking of packets with big enough coordinate-momentum correlation coefficients (followed by the well known expansion) is discovered. This happens due to a competition of ‘focusing’ and ‘de-focusing’ in the orthogonal directions. (paper)

  16. SU-E-T-463: Quantification of Rotational Variation in Mouse Setup for IGRT

    Energy Technology Data Exchange (ETDEWEB)

    McCarroll, R; Rubinstein, A; Kingsley, C; Yang, J; Yang, P; Court, L [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: New small-animal irradiators include extremely precise IGRT capabilities. However, mouse immobilization and localization remains a challenge. In particular, unlike week-to-week translational displacements, rotational changes in positioning are not easily corrected for in subject setup. Using two methods of setup, we aim to quantify week-to-week rotational variation in mice for the purpose of IGRT planning in small animal studies. Methods: Ten mice were imaged weekly using breath-hold CBCT (X-RAD 225 Cx), with the mouse positioned in a half-pipe support, providing 40 scans. A second group of two mice were positioned in a 3D printed immobilization device, which was created using a CT from a similarly shaped mouse, providing 10 scans. For each mouse, the first image was taken to be the reference image. Subsequent CT images were then rigidly registered, based on bony anatomy. Rotations in the axial (roll), sagittal (pitch), and coronal (yaw) planes were recorded and used to quantify variation in angular setup. Results: For the mice imaged in the half pipe, average magnitude of roll was found to be 5.4±4.6° (range: −12.9:18.86°), of pitch 1.6±1.3° (range: −1.4:4.7°), and of yaw 1.9±1.5° (range −5.4:1.1°). For the mice imaged in the printed setup; average magnitude of roll was found to be 0.64±0.6° (range: −2.1:1.0°), of pitch 0.6±0.4° (range: 0.0:1.3°), and of yaw 0.2±0.1° (range: 0.0:0.4°). The printed setup provided reduction in roll, pitch, and yaw by 88, 62, and 90 percent, respectively. Conclusion: For the typical setup routine, roll in mouse position is the dominant source of rotational variation. However, when a printed device was used, drastic improvements in mouse immobilization were seen. This work provides a promising foundation for mouse immobilization, required for full scale small animal IGRT. Currently, we are making improvements to allo±w the use of a similar system for MR, PET, and bioluminescence.

  17. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

    Energy Technology Data Exchange (ETDEWEB)

    Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Street, 603950 Nizhny Novgorod (Russian Federation); Ilyushin, V. V.; Mescheryakov, A. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Alekseev, E. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Quantum Radiophysics Department of V. N. Karazin Kharkiv National University, Svobody Square 4, 61022 Kharkov (Ukraine); Hougen, J. T., E-mail: jon.hougen@nist.gov [Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441 (United States); Xu, Li-Hong [Department of Physics and Centre for Laser, Atomic, and Molecular Sciences, University of New Brunswick, Saint John, New Brunswick E2L 4L5 (Canada)

    2016-07-14

    This paper presents an explanation based on torsionally mediated proton-spin–overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = − 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric “torsionally mediated spin-rotation operators” by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e{sup ±niα}. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A{sub 1} and A{sub 2} states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

  18. Strategic Considerations for Effective Sagittal Resection of the Mandible to Achieve a Slim and Attractive Jawline.

    Science.gov (United States)

    Park, Sanghoon; Lee, Tae Sung

    2018-01-01

    Sagittal resection of the mandible has been widely used to reduce the width of the lower face and is usually carried out in combination with a mandibular contouring procedure. However, the surgical outcomes of this procedure are unclear because sagittal resection is rarely performed as a single procedure. The authors clarify misunderstandings regarding this procedure and introduce an improved strategic approach for sagittal resection of the mandible. Under general anesthesia, mandible contouring was performed first with a curved osteotomy, followed by sagittal resection of the outer cortex of mandible. The amount and extent of each procedure was determined in accordance with preoperative analysis. From 2012 to 2014, a consecutive series of 212 patients who underwent mandible contouring surgery without concomitant chin surgery were included in the study. A total of 189 patients underwent both mandibular contouring surgery and sagittal resection, whereas 13 underwent only sagittal resection and 10 underwent only mandibular contouring surgery. All operations were carried out successfully without any severe complications, and most patients had satisfactory aesthetic outcomes. The authors found that the sagittal resection of the mandible should be performed in accordance with the shape of the mandible to effectively reduce facial width and achieve better aesthetic outcomes for both profile and frontal views. In an outcurved-type mandible, conventional mandibular contouring may be effective alone, whereas sagittal resection focusing on removing the mandible body region is essential for incurved-type mandibles. In straight line-type mandibles, both procedures are necessary. Therapeutic, IV.

  19. Analysis of toroidal rotation data for the DIII-D tokamak

    International Nuclear Information System (INIS)

    St John, H.; Stroth, U.; Burrell, K.H.; Groebner, R.J.; DeBoo, J.C.; Gohil, P.

    1989-01-01

    Both poloidal and toroidal rotation are observed during routine neutral beam heating operation of the DIII-D tokamak. Poloidal rotation results and the empirical techniques used to measure toroidal and poloidal rotation speeds are described by Groebner. Here we concentrate on the analysis of recent measurements of toroidal rotation made during diverted, H-mode operation of the DIII-D tokamak during co- and counter-neutral beam injection of hydrogen into deuterium plasmas. Our results are based on numerical inversions using the transport code ONETWO, modified to account for the radial diffusion of toroidal angular momentum. 13 refs., 4 figs

  20. Gravitational Metric Tensor Exterior to Rotating Homogeneous ...

    African Journals Online (AJOL)

    The covariant and contravariant metric tensors exterior to a homogeneous spherical body rotating uniformly about a common φ axis with constant angular velocity ω is constructed. The constructed metric tensors in this gravitational field have seven non-zero distinct components.The Lagrangian for this gravitational field is ...

  1. Cosmic numbers and rotation of the metagalaxy

    International Nuclear Information System (INIS)

    Muradyan, R.M.

    1976-01-01

    The well known ''cosmological coincidences'' of Stewart and Dirac relating fundamental constants of micro- and megaphysics are discussed. It is shown that the relations can be derived on the basis of the hypothesis on possible rotation of Metagalaxy. A new relation for the angular momentum of Metagalaxy is obtained

  2. Rotation of a magnesium plasma column in a background gas

    International Nuclear Information System (INIS)

    Bosco, E. Del; Dallaqua, R.S.

    1993-01-01

    Measurements of the angular velocity of a plasma column in a surrounding gas atmosphere are presented. The plasma is produced by a pulsed, high current arc discharge in the presence of an axial magnetic field. The angular velocity is measured using the cross correlation technique applied to the floating potential signals measured by two Langmuir probes. The main result is that when gas is added to the discharge the angular velocity is always lower than the case when there is no gas, this effect been more pronounced in the beginning of the discharge. For pressures higher than ∼ 2 x 10 -2 Pa there is a effect of the gas on the plasma column rotation and the angular velocity diminishes even at the end of discharge. (author)

  3. Magneto-rotational instability in differentially rotating liquid metals

    International Nuclear Information System (INIS)

    Velikhov, E.P.; Ivanov, A.A.; Lakhin, V.P.; Serebrennikov, K.S.

    2006-01-01

    We study the stability of Couette flow between two cylinders in the presence of axial magnetic field in local WKB approximation. We find the analytical expression of the critical angular velocity minimized over the wave number and the imposed magnetic field as a function of the measure of deviation of the rotation law from the Rayleigh line. The result found is in a good agreement with the previously known numerical results based on the global analysis. We perform a minimization of the critical Reynolds number over the wave number at fixed magnetic field both analytically and numerically. We show that a compromise between resistive suppression of magneto-rotational instability at weak magnetic field and the increase of the critical Reynolds number with the increase of magnetic field is possible. It takes place at moderate values of magnetic field of order 3x10 2 gauss giving the critical Reynolds number of order 4x10 4

  4. Rotation-supported Neutrino-driven Supernova Explosions in Three Dimensions and the Critical Luminosity Condition

    Science.gov (United States)

    Summa, Alexander; Janka, Hans-Thomas; Melson, Tobias; Marek, Andreas

    2018-01-01

    We present the first self-consistent, 3D core-collapse supernova simulations performed with the PROMETHEUS-VERTEX code for a rotating progenitor star. Besides using the angular momentum of the 15 M ⊙ model as obtained in the stellar evolution calculation with an angular frequency of ∼10‑3 rad s‑1 (spin period of more than 6000 s) at the Si/Si–O interface, we also computed 2D and 3D cases with no rotation and with a ∼300 times shorter rotation period and different angular resolutions. In 2D, only the nonrotating and slowly rotating models explode, while rapid rotation prevents an explosion within 500 ms after bounce because of lower radiated neutrino luminosities and mean energies and thus reduced neutrino heating. In contrast, only the fast-rotating model develops an explosion in 3D when the Si/Si–O interface collapses through the shock. The explosion becomes possible by the support of a powerful standing accretion shock instability spiral mode, which compensates for the reduced neutrino heating and pushes strong shock expansion in the equatorial plane. Fast rotation in 3D leads to a “two-dimensionalization” of the turbulent energy spectrum (yielding roughly a ‑3 instead of a ‑5/3 power-law slope at intermediate wavelengths) with enhanced kinetic energy on the largest spatial scales. We also introduce a generalization of the “universal critical luminosity condition” of Summa et al. to account for the effects of rotation, and we demonstrate its viability for a set of more than 40 core-collapse simulations, including 9 and 20 M ⊙ progenitors, as well as black-hole-forming cases of 40 and 75 M ⊙ stars to be discussed in forthcoming papers.

  5. SAGITTAL DIAMETER OF FORAMEN MAGNUM IN NORMAL POPULATION: AN MRI STUDY

    OpenAIRE

    Lakshmi

    2015-01-01

    Lower position of cerebellar tonsils was frequently noticed in Western studies. In some of the studies, sagittal diameter of foramen magnum was found to be larger in cases of Chiari malformation. However, there are no Indian studies for comparison. Our study was proposed to determine the standard values for sagittal diameter of foramen magnum in various age groups and both sexes. This gives a guideline for further studies in pathological conditions like Craniovertebral Junctional ...

  6. Rotation of gas above the galactic disk

    International Nuclear Information System (INIS)

    Gvaramadze, V.V.; Lominadze, D.G.

    1988-01-01

    The galactic disk is modeled by an oblate spheroid with confocal spherodial isodensity surfaces. An explicit analytic expression is found for the angular velocity of the gas outside the disk. The parameters of a three-component model of a spiral galaxy (oblate spheroid with central hole, bulge, and massive corona) are chosen in such a way as to obtain in the disk a two-hump rotation curve (as in the Galaxy, M 31, and M 81). It is shown that at heights absolute value z ≤ 2 kpc the gas rotates in the same manner as the disk. However, at greater heights the rotation curve ceases to have two humps. Allowance for the pressure gradient of the gas slightly changes the rotation curve directly above the disk (r r/sub disk/)

  7. INTERNAL ROTATION OF THE RED-GIANT STAR KIC 4448777 BY MEANS OF ASTEROSEISMIC INVERSION

    Energy Technology Data Exchange (ETDEWEB)

    Di Mauro, M. P.; Cardini, D. [INAF, IAPS Istituto di Astrofisica e Planetologia Spaziali, Roma (Italy); Ventura, R.; Paternò, L. [INAF, Astrophysical Observatory of Catania, Catania (Italy); Stello, D. [Sydney Institute for Astronomy, School of Physics, University of Sydney (Australia); Christensen-Dalsgaard, J.; Hekker, S. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Dziembowski, W. A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Beck, P. G.; De Smedt, K.; Tkachenko, A. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven (Belgium); Bloemen, S. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Davies, G. R.; Garcia, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Univ. Paris Diderot, IRFU/Sap, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Elsworth, Y. [School of Physics and Astronomy, University of Birmingham (United Kingdom); Mosser, B. [LESIA, PSL Research University, CNRS, Universitè Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, Meudon Cedex (France)

    2016-01-20

    We study the dynamics of the stellar interior of the early red-giant star KIC 4448777 by asteroseismic inversion of 14 splittings of the dipole mixed modes obtained from Kepler observations. In order to overcome the complexity of the oscillation pattern typical of red-giant stars, we present a procedure to extract the rotational splittings from the power spectrum. We find not only that the core rotates from a minimum of 8 to a maximum of 17 times faster than the surface, confirming previous inversion results generated for other red giants (Deheuvels et al.), but we also estimate the variation of the angular velocity within the helium core with a spatial resolution of 0.001R and verify the hypothesis of a sharp discontinuity in the inner stellar rotation. The results show that the entire core rotates rigidly and provide evidence for an angular velocity gradient around the base of the hydrogen-burning shell; however, we do not succeed in characterizing the rotational slope, due to the intrinsic limits of the applied techniques. The angular velocity, from the edge of the core, appears to decrease with increasing distance from the center, reaching an average value in the convective envelope of 68 ± 22 nHz. We conclude that a set of data that includes only dipolar modes is sufficient to infer quite accurately the rotation of a red giant not only in the dense core but also, with a lower level of confidence, in part of the radiative region and in the convective envelope.

  8. Gamma-ray multiplicity measurements and angular momentum transfer in deeply inelastic collisions

    International Nuclear Information System (INIS)

    Perrin, N.; Peter, J.

    1977-01-01

    In DIC, the part of the initial orbital angular momentum l which is transferred into internal angular momenta Δl of the fragments depends on the degree of cohesion of the composite system. The (few) measured gamma-rays multiplicities are compared to those observed for similar compound nuclei and for fission fragments. Δl increases with the kinetic energy relaxation. For medium-mass systems, the cohesion varies continuously from the rolling to the sticking situation when the decay time of the composite system increases. The rigid body situation is obtained for a small part of the relaxed events. For heavy systems, rigid rotation seems to be much more common, which will allow to extract information on the deflection function. The time needed to reach the rigid situation is intermediate between those of kinetic energy relaxation and mass asymmetry relaxation. An additional angular momentum can be added in the fragments, due to a bending mode at the scission-point, like in fission. That can explain the observed low anisotropy of the gamma-rays angular distribution

  9. Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles

    Science.gov (United States)

    Marzo, Asier; Caleap, Mihai; Drinkwater, Bruce W.

    2018-01-01

    Acoustic vortices can transfer angular momentum and trap particles. Here, we show that particles trapped in airborne acoustic vortices orbit at high speeds, leading to dynamic instability and ejection. We demonstrate stable trapping inside acoustic vortices by generating sequences of short-pulsed vortices of equal helicity but opposite chirality. This produces a "virtual vortex" with an orbital angular momentum that can be tuned independently of the trapping force. We use this method to adjust the rotational speed of particles inside a vortex beam and, for the first time, create three-dimensional acoustics traps for particles of wavelength order (i.e., Mie particles).

  10. 'Lumbar Degenerative Kyphosis' Is Not Byword for Degenerative Sagittal Imbalance: Time to Replace a Misconception.

    Science.gov (United States)

    Lee, Chang-Hyun; Chung, Chun Kee; Jang, Jee-Soo; Kim, Sung-Min; Chin, Dong-Kyu; Lee, Jung-Kil

    2017-03-01

    Lumbar degenerative kyphosis (LDK) is a subgroup of the flat-back syndrome and is most commonly caused by unique life styles, such as a prolonged crouched posture during agricultural work and performing activities of daily living on the floor. Unfortunately, LDK has been used as a byword for degenerative sagittal imbalance, and this sometimes causes confusion. The aim of this review was to evaluate the exact territory of LDK, and to introduce another appropriate term for degenerative sagittal deformity. Unlike what its name suggests, LDK does not only include sagittal balance disorder of the lumbar spine and kyphosis, but also sagittal balance disorder of the whole spine and little lordosis of the lumbar spine. Moreover, this disease is closely related to the occupation of female farmers and an outdated Asian life style. These reasons necessitate a change in the nomenclature of this disorder to prevent misunderstanding. We suggest the name "primary degenerative sagittal imbalance" (PDSI), which encompasses degenerative sagittal misalignments of unknown origin in the whole spine in older-age patients, and is associated with back muscle wasting. LDK may be regarded as a subgroup of PDSI related to an occupation in agriculture. Conservative treatments such as exercise and physiotherapy are recommended as first-line treatments for patients with PDSI, and surgical treatment is considered only if conservative treatments failed. The measurement of spinopelvic parameters for sagittal balance is important prior to deformity corrective surgery. LDK can be considered a subtype of PDSI that is more likely to occur in female farmers, and hence the use of LDK as a global term for all degenerative sagittal imbalance disorders is better avoided. To avoid confusion, we recommend PDSI as a newer, more accurate diagnostic term instead of LDK.

  11. Fabrication of quartz microcylinders by laser interference lithography for angular optical tweezers

    Science.gov (United States)

    Santybayeva, Zhanna; Meghit, Afaf; Desgarceaux, Rudy; Teissier, Roland; Pichot, Frederic; de Marin, Charles; Charlot, Benoit; Pedaci, Francesco

    2016-07-01

    The use of optical tweezers (OTs) and spin angular momentum transfer to birefringent particles allows new mechanical measurements in systems where torque and rotation are relevant parameters at the single-molecule level. There is a growing interest in developing simple, fast, and inexpensive protocols to produce a large number of submicron scale cylinders of quartz, a positive uniaxial birefringent crystal, to be employed for such angular measurements in OTs. Here, we show that laser interference lithography, a method well known for its simplicity, fulfills these requirements and produces quartz cylindrical particles that we successfully use to apply and measure optical torque in the piconewton nm range in an optical torque wrench.

  12. Measuring Fractional Anisotropy of the Corpus Callosum Using Diffusion Tensor Imaging: Mid-Sagittal versus Axial Imaging Planes

    International Nuclear Information System (INIS)

    Kim, Eung Yeop; Park, Hae Jeong; Kim, Dong Hyun; Lee, Seung Koo; Kim, Jin Na

    2008-01-01

    Many diffusion tensor imaging (DTI) studies of the corpus callosum (CC) have been performed with a relatively thick slice thickness in the axial plane, which may result in underestimating the fractional anisotropy (FA) of the CC due to a partial volume effect. We hypothesized that the FA of the CC can be more accurately measured by using mid-sagittal DTI. We compared the FA values of the CC between the axial and mid-sagittal DTI. Fourteen healthy volunteers underwent MRI at 3.0 T. DTI was performed in both the mid-sagittal and axial planes. One 5-mm mid-sagittal image and twenty-five 2-mm axial images were obtained for the CC. The five regions of interest (ROIs) that included the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) were drawn along the border of the CC on each sagittal FA map. The FA values obtained from each region were compared between the two sagittal maps. The FA values of all the regions, except for region V, were significantly increased on the mid-sagittal imaging. The FA values in region IV were significantly underestimated on the mid-sagittal image from the axial imaging, compared with those in the regions I and V (p = 0.037 and p = 0.001, respectively). The FA values of the CC were significantly higher on the midsagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV. Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects

  13. On the Cauchy problem for nonlinear Schrödinger equations with rotation

    KAUST Repository

    Antonelli, Paolo; Marahrens, Daniel; Sparber, Christof

    2011-01-01

    We consider the Cauchy problem for (energy-subcritical) nonlinear Schrödinger equations with sub-quadratic external potentials and an additional angular momentum rotation term. This equation is a well-known model for superuid quantum gases in rotating traps. We prove global existence (in the energy space) for defocusing nonlinearities without any restriction on the rotation frequency, generalizing earlier results given in [11, 12]. Moreover, we find that the rotation term has a considerable in fiuence in proving finite time blow-up in the focusing case.

  14. On the Cauchy problem for nonlinear Schrödinger equations with rotation

    KAUST Repository

    Antonelli, Paolo

    2011-10-01

    We consider the Cauchy problem for (energy-subcritical) nonlinear Schrödinger equations with sub-quadratic external potentials and an additional angular momentum rotation term. This equation is a well-known model for superuid quantum gases in rotating traps. We prove global existence (in the energy space) for defocusing nonlinearities without any restriction on the rotation frequency, generalizing earlier results given in [11, 12]. Moreover, we find that the rotation term has a considerable in fiuence in proving finite time blow-up in the focusing case.

  15. Sagittal Alignment As a Predictor of Clinical Adjacent Segment Pathology requiring Surgery after Anterior Cervical Arthrodesis

    Science.gov (United States)

    Park, Moon Soo; Kelly, Michael P.; Lee, Dong-Ho; Min, Woo-Kie; Rahman, Ra’Kerry K.; Riew, K. Daniel

    2014-01-01

    BACKGROUND CONTEXT Postoperative malalignment of the cervical spine may alter cervical spine mechanics, and put patients at risk for clinical adjacent segment pathology requiring surgery. PURPOSE To investigate whether a relationship exists between cervical spine sagittal alignment and clinical adjacent segment pathology requiring surgery (CASP-S) following anterior cervical fusion (ACF). STUDY DESIGN Retrospective matched study. PATIENT SAMPLE One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 2 year follow-up. OUTCOME MEASURES Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. METHODS One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 1 year follow-up. Patients were divided into groups according to the development of CASP requiring surgery (Control / CASP-S) and by number/location of levels fused. Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. Appropriate statistical tests were performed to calculate relationships between the variables and the development of CASP-S. No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related

  16. Distribution of rotational velocities for low-mass stars in the Pleiades

    International Nuclear Information System (INIS)

    Stauffer, J.R.; Hartmann, L.W.; Dominion Astrophysical Observatory, Victoria, Canada; Smithsonian Astrophysical Observatory, Cambridge, MA)

    1987-01-01

    The available spectral type and color data for late-type Pleiades members have been reanalyzed, and new reddening estimates are obtained. New photometry for a small number of stars and a compilation of H-alpha equivalent widths for Pleiades dwarfs are presented. These data are used to examine the location of the rapid rotators in color-magnitude diagrams and the correlation between chromospheric activity and rotation. It is shown that the wide range of angular momenta exhibited by Pleiades K and M dwarfs is not necessarily produced by a combination of main-sequence spin-downs and a large age spread; it can also result from a plausible spread in initial angular momenta, coupled with initial main-sequence spin-down rates that are only weakly dependent on rotation. The new reddening estimates confirm Breger's (1985) finding of large extinctions confined to a small region in the southern portion of the Merope nebula. 79 references

  17. A novel energy-efficient rotational variable stiffness actuator

    NARCIS (Netherlands)

    Rao, S.; Carloni, Raffaella; Stramigioli, Stefano

    This paper presents the working principle, the design and realization of a novel rotational variable stiffness actuator, whose stiffness can be varied independently of its output angular position. This actuator is energy-efficient, meaning that the stiffness of the actuator can be varied by keeping

  18. Comparison of accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions: An exvivo study

    Directory of Open Access Journals (Sweden)

    Asieh Zamani Naser

    2010-01-01

    Full Text Available Background: Radiographic examination of TMJ is indicated when there are clinical signs of pathological conditions, mainly bone changes that may influence the diagnosis and treatment planning. The purpose of this study was to evaluate and to compare the validity and diagnostic accuracy of uncorrected and corrected sagittal tomographic images in the detection of simulated mandibular condyle erosions. Methods : Simulated lesions were created in 10 dry mandibles using a dental round bur. Using uncorrected and corrected sagittal tomography techniques, mandibular condyles were imaged by a Cranex Tome X-ray unit before and after creating the lesions. The uncorrected and corrected tomography images were examined by two independent observers for absence or presence of a lesion. The accuracy for detecting mandibular condyle lesions was expressed as sensitivity, specificity, and validity values. Differences between the two radiographic modalities were tested by Wilcoxon for paired data tests. Inter-observer agreement was determined by Cohen′s Kappa. Results: The sensitivity, specificity and validity were 45%, 85% and 30% in uncorrected sagittal tomographic images, respectively, and 70%, 92.5% and 60% in corrected sagittal tomographic images, respectively. There was a significant statistical difference between the accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions (P = 0.016. The inter-observer agreement was slight for uncorrected sagittal tomography and moderate for corrected sagittal tomography. Conclusion: The accuracy of corrected sagittal tomography is significantly higher than that of uncorrected sagittal tomography. Therefore, corrected sagittal tomography seems to be a better modality in detection of mandibular condyle erosions.

  19. Thermocapillary instabilities in a laterally heated liquid bridge with end wall rotation

    Science.gov (United States)

    Kahouadji, L.; Houchens, B. C.; Witkowski, L. Martin

    2011-10-01

    The effect of rotation on the stability of thermocapillary driven flow in a laterally heated liquid bridge is studied numerically using the full-zone model of the floating-zone crystal growth technique. A small Prandtl number (0.02) fluid, relevant for semiconductor melts, is studied with an aspect ratio (height to diameter of the melt) equal to one. Buoyancy is neglected. A linear stability analysis of three-dimensional perturbations is performed and shows that for any ratio of angular velocities, a weak rotation rate has the surprising effect of destabilizing the base flow. By systematically varying the rotation rate and ratio of angular velocities, the critical threshold and azimuthal wave number of the most unstable mode is found over a wide range of this two parameter space. Depending on these parameters, the leading eigenmode is a wave propagating either in the positive or negative azimuthal direction, with kinetic energy typically localized close to one of the end walls. These results are of practical interest for industrial crystal growth applications, where rotation is often used to obtain higher quality crystals.

  20. Relative Attitude Estimation for a Uniform Motion and Slowly Rotating Noncooperative Spacecraft

    Directory of Open Access Journals (Sweden)

    Liu Zhang

    2017-01-01

    Full Text Available This paper presents a novel relative attitude estimation approach for a uniform motion and slowly rotating noncooperative spacecraft. It is assumed that the uniform motion and slowly rotating noncooperative chief spacecraft is in failure or out of control and there is no a priori rotation rate information. We utilize a very fast binary descriptor based on binary robust independent elementary features (BRIEF to obtain the features of the target, which are rotational invariance and resistance to noise. And then, we propose a novel combination of single candidate random sample consensus (RANSAC with extended Kalman filter (EKF that makes use of the available prior probabilistic information from the EKF in the RANSAC model hypothesis stage. The advantage of this combination obviously reduces the sample size to only one, which results in large computational savings without the loss of accuracy. Experimental results from real image sequence of a real model target show that the relative angular error is about 3.5% and the mean angular velocity error is about 0.1 deg/s.

  1. Effects on a Landau-type system for a neutral particle with no permanent electric dipole moment subject to the Kratzer potential in a rotating frame.

    Science.gov (United States)

    Oliveira, Abinael B; Bakke, Knut

    2016-06-01

    The behaviour of a neutral particle (atom, molecule) with an induced electric dipole moment in a region with a uniform effective magnetic field under the influence of the Kratzer potential (Kratzer 1920 Z. Phys. 3 , 289-307. (doi:10.1007/BF01327754)), and rotating effects is analysed. It is shown that the degeneracy of the Landau-type levels is broken and the angular frequency of the system acquires a new contribution that stems from the rotation effects. Moreover, in the search for bound state solutions, it is shown that the possible values of this angular frequency of the system are determined by the quantum numbers associated with the radial modes and the angular momentum, the angular velocity of the rotating frame and by the parameters associated with the Kratzer potential.

  2. The distribution of rotational velocities for low-mass stars in the Pleiades

    Science.gov (United States)

    Stauffer, John R.; Hartmann, Lee W.

    1987-01-01

    The available spectral type and color data for late-type Pleiades members have been reanalyzed, and new reddening estimates are obtained. New photometry for a small number of stars and a compilation of H-alpha equivalent widths for Pleiades dwarfs are presented. These data are used to examine the location of the rapid rotators in color-magnitude diagrams and the correlation between chromospheric activity and rotation. It is shown that the wide range of angular momenta exhibited by Pleiades K and M dwarfs is not necessarily produced by a combination of main-sequence spin-downs and a large age spread; it can also result from a plausible spread in initial angular momenta, coupled with initial main-sequence spin-down rates that are only weakly dependent on rotation. The new reddening estimates confirm Breger's (1985) finding of large extinctions confined to a small region in the southern portion of the Merope nebula.

  3. Rotation-invariant observables in parity-violating decays of vector particles to fermion pairs

    CERN Document Server

    Faccioli, Pietro; Seixas, Joao; Wohri, Hermine K

    2010-01-01

    The di-fermion angular distribution observed in decays of inclusively produced vector particles is characterized by two frame-independent observables, reflecting the average spin-alignment of the produced particle and the magnitude of parity violation in the decay. The existence of these observables derives from the rotational properties of angular momentum eigenstates and is a completely general result, valid for any J=1 state and independent of the production process. Rotation-invariant formulations of polarization and of the decay parity-asymmetry can provide more significant measurements than the commonly used frame-dependent definitions, also improving the quality of the comparisons between the measurements and the theoretical calculations.

  4. Rotation-invariant observables in parity-violating decays of vector particles to fermion pairs

    International Nuclear Information System (INIS)

    Faccioli, Pietro; Woehri, Hermine K.; Lourenco, Carlos; Seixas, Joao

    2010-01-01

    The di-fermion angular distribution observed in decays of inclusively produced vector particles is characterized by two frame-independent observables, reflecting the average spin alignment of the produced particle and the magnitude of parity violation in the decay. The existence of these observables derives from the rotational properties of angular momentum eigenstates and is a completely general result, valid for any J=1 state and independent of the production process. Rotation-invariant formulations of polarization and of the decay parity asymmetry can provide more significant measurements than the commonly used frame-dependent definitions, also improving the quality of the comparisons between the measurements and the theoretical calculations.

  5. Direct CT scanning of the lesser pelvis - frontal vs sagittal plane

    International Nuclear Information System (INIS)

    Khadzhigeorgiev, G.; Lichev, A.

    1994-01-01

    Whenever axial scanning alone is used, the anatomical patterns of the true pelvis and the organs contained in it, particularly in women, give rise to diagnostic difficulties during CT assessment of neoplasms originating from these organs. The high demands on precision characterization of the pathological changes in the pelvis minor organs necessitate the obtaining of reliable density and size measurement data, not merely from the axial plane, but from the frontal and sagittal ones as well. The deficient information afforded by secondary reconstruction of the pelvis mind images requires an mandatory evaluation of the potentialities of direct frontal and direct sagittal scanning of the pelvis minor using standard CT equipment. Information yielded by images from direct frontal and direct sagittal pelvis minor scanning as well as diagnostic problems where application of this type of scanning is indicated operational difficulties and their overcoming, are among the issues discussed. 8 figs., 7 refs

  6. A comparison of cephalometric analyses for assessing sagittal jaw relationship

    International Nuclear Information System (INIS)

    Erum, G.; Fida, M.

    2008-01-01

    To compare the seven methods of cephalometric analysis for assessing sagittal jaw relationship and to determine the level of agreement between them. Seven methods, describing anteroposterior jaw relationships (A-B plane, ANB, Wits, AXB, AF-BF, FABA and Beta angle) were measured on the lateral cephalographs of 85 patients. Correlation analysis, using Cramer's V-test, was performed to determine the possible agreement between the pair of analyses. The mean age of the sample, comprising 35 males and 50 females was 15 years and 3 months. Statistically significant relationships were found among seven sagittal parameters with p-value <0.001. Very strong correlation was found between AXB and AF-BF distance (r=0.924); and weak correlation between ANB and Beta angle (r=0.377). Wits appraisal showed the greatest coefficient of variability. Despite varying strengths of association, statistically significant correlations were found among seven methods for assessing sagittal jaw relationship. FABA and A-B plane may be used to predict the skeletal class in addition to the established ANB angle. (author)

  7. PARAMETERS FOR THE EVALUATION OF CERVICAL SAGITTAL BALANCE IN IDIOPATHIC SCOLIOSIS

    Directory of Open Access Journals (Sweden)

    MAURICIO COELHO LIMA

    Full Text Available ABSTRACT Objective: There are no values defined as standard in the literature for the parameters of assessment of cervical sagittal balance in patients with idiopathic scoliosis. This study describes the sagittal cervical parameters in patients with idiopathic scoliosis. Methods: Study carried out in a tertiary public hospital in patients with adolescent idiopathic scoliosis, through the evaluation of panoramic radiographs in lateral view. The Cobb method was used to evaluate cervical lordosis from C2 to C7, distance from the center of gravity (COG of the skull to C7, measurement of T1 slope, thoracic inlet angle (TIA, neck tilt, and plumb line from C7 to S1 (SVA C7-S1. A statistical analysis was performed, to demonstrate the relationship between the alignment of the thoracic spine in the sagittal plane and the cervical sagittal balance of patients with scoliosis. Results: Thirty-four patients were female (69.4% and 15 male (30.6%. The mean values for COG-C7 were 0.71 mm (median 0.8 mm/standard deviation [SD]= 0.51 mm. For Cobb C2-C7, the mean was -11.7° (median -10°/SD= 20.4°. The mean slope of T1 was 23.5° (median 25°/SD= 9.5°. The mean cervical version was 58.8° (median 60°/DP= 15.4°. The mean TIA was 81.8° (median 85°/SD= 16.7°. The mean plumb line C7-S1 was -0.28 (-0.3/SD= 1.0. Conclusion: The analysis of the results showed that the mean values for the cervical lordosis are lower than the values described as normal in the literature, suggesting a loss of sagittal cervical balance in these patients.

  8. ANGULAR MOMENTUM IN GIANT MOLECULAR CLOUDS. II. M33

    International Nuclear Information System (INIS)

    Imara, Nia; Bigiel, Frank; Blitz, Leo

    2011-01-01

    We present an analysis comparing the properties of 45 giant molecular clouds (GMCs) in M33 and the atomic hydrogen (H I) with which they are associated. High-resolution Very Large Array observations are used to measure the properties of H I in the vicinity of GMCs and in regions where GMCs have not been detected. The majority of molecular clouds coincide with a local peak in the surface density of atomic gas, though 7% of GMCs in the sample are not associated with high surface density atomic gas. The mean H I surface density in the vicinity of GMCs is 10 M sun pc -2 and tends to increase with GMC mass as Σ HI ∝ M 0.27 GMC . Thirty-nine of the 45 H I regions surrounding GMCs have linear velocity gradients of ∼0.05 km s -1 pc -1 . If the linear gradients previously observed in the GMCs result from rotation, 53% are counterrotating with respect to the local H I. And if the linear gradients in these local H I regions are also from rotation, 62% are counterrotating with respect to the galaxy. If magnetic braking reduced the angular momentum of GMCs early in their evolution, the angular velocity of GMCs would be roughly one order of magnitude lower than what is observed. Based on our observations, we consider the possibility that GMCs may not be rotating. Atomic gas not associated with GMCs has gradients closer to 0.03 km s -1 pc -1 , suggesting that events occur during the course of GMC evolution that may increase the shear in the atomic gas.

  9. Comparison of length of day with oceanic and atmospheric angular momentum series

    Czech Academy of Sciences Publication Activity Database

    Kouba, J.; Vondrák, Jan

    2005-01-01

    Roč. 79, 4-5 (2005), s.256-268 ISSN 0949-7714 R&D Projects: GA AV ČR IAA3003205; GA MŠk LC506 Institutional research plan: CEZ:AV0Z10030501 Keywords : Earth rotation * length of day * atmospheric angular momentum Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.205, year: 2005

  10. Aerodynamics in the amusement park: interpreting sensor data for acceleration and rotation

    Science.gov (United States)

    Löfstrand, Marcus; Pendrill, Ann-Marie

    2016-09-01

    The sky roller ride depends on interaction with the air to create a rolling motion. In this paper, we analyse forces, torque and angular velocities during different parts of the ride, combining a theoretical analysis, with photos, videos as well as with accelerometer and gyroscopic data, that may be collected e.g. with a smartphone. For interpreting the result, it must be taken into account that the sensors and their coordinate system rotate together with the rider. The sky roller offers many examples for physics education, from simple circular motion, to acceleration and rotation involving several axes, as well as the relation between wing orientation, torque and angular velocities and using barometer pressure to determine the elevation gain.

  11. Spinning rate decay of levitated high-Tc superconductors in rotational magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Terentiev, A.N.; Kutukova, E.O.; Kuznetsov, A.A. (Inst. of Chemical Physics, Academy of Sciences, Moscow (Russia)); Mozhaev, A.P. (Moscow State Univ., Dept. of Chemistry (Russia))

    1992-04-01

    The rotation damping of a levitated superconductor was examined in the static field of a ring-shaped magnet and in the rotating field of coils. It was demonstrated that the pinning force mainly contributed to magnetic friction while the influence of a viscous component was negligible. The rotating magnetic field created a torque, reducing the angular deceleration under relaxation. Dependence of the rotational field-induced torque on the field-intensity was step-like. A relationship between the step-like behavior of rotational field-induced torque and pinning center distribution is discussed. The origins of friction torque and rotational field-produced torque are discussed. (orig.).

  12. Rotational mixing in carbon-enhanced metal-poor stars with s-process enrichment

    Science.gov (United States)

    Matrozis, E.; Stancliffe, R. J.

    2017-10-01

    Carbon-enhanced metal-poor (CEMP) stars with s-process enrichment (CEMP-s) are believed to be the products of mass transfer from an asymptotic giant branch (AGB) companion, which has long since become a white dwarf. The surface abundances of CEMP-s stars are thus commonly assumed to reflect the nucleosynthesis output of the first AGB stars. We have previously shown that, for this to be the case, some physical mechanism must counter atomic diffusion (gravitational settling and radiative levitation) in these nearly fully radiative stars, which otherwise leads to surface abundance anomalies clearly inconsistent with observations. Here we take into account angular momentum accretion by these stars. We compute in detail the evolution of typical CEMP-s stars from the zero-age main sequence, through the mass accretion, and up the red giant branch for a wide range of specific angular momentum ja of the accreted material, corresponding to surface rotation velocities, vrot, between about 0.3 and 300 kms-1. We find that only for ja ≳ 1017 cm2s-1 (vrot > 20 kms-1, depending on mass accreted) angular momentum accretion directly causes chemical dilution of the accreted material. This could nevertheless be relevant to CEMP-s stars, which are observed to rotate more slowly, if they undergo continuous angular momentum loss akin to solar-like stars. In models with rotation velocities characteristic of CEMP-s stars, rotational mixing primarily serves to inhibit atomic diffusion, such that the maximal surface abundance variations (with respect to the composition of the accreted material) prior to first dredge-up remain within about 0.4 dex without thermohaline mixing or about 0.5-1.5 dex with thermohaline mixing. Even in models with the lowest rotation velocities (vrot ≲ 1 kms-1), rotational mixing is able to severely inhibit atomic diffusion, compared to non-rotating models. We thus conclude that it offers a natural solution to the problem posed by atomic diffusion and cannot be

  13. Angular deflection of rotary nickel titanium files: a comparative study

    Directory of Open Access Journals (Sweden)

    Gianluca Gambarini

    2009-12-01

    Full Text Available A new manufacturing method of twisting nickel titanium wire to produce rotary nickel titanium (RNT files has recently been developed. The aim of the present study was to evaluate whether the new manufacturing process increased the angular deflection of RNT files, by comparing instruments produced using the new manufacturing method (Twisted Files versus instruments produced with the traditional grinding process. Testing was performed on a total of 40 instruments of the following commercially available RNT files: Twisted Files (TF, Profile, K3 and M2 (NRT. All instruments tested had the same dimensions (taper 0.06 and tip size 25. Test procedures strictly followed ISO 3630-1. Data were collected and statistically analyzed by means ANOVA test. The results showed that TF demonstrated significantly higher average angular deflection levels (P<0.05, than RNT manufactured by a grinding process. Since angular deflection represent the amount of rotation (and consequently deformation that a RNT file can withstand before torsional failure, such a significant improvement is a favorable property for the clinical use of the tested RNT files.

  14. Sagittal plane analysis of the spine and pelvis in degenerative lumbar scoliosis.

    Science.gov (United States)

    Han, Fei; Weishi, Li; Zhuoran, Sun; Qingwei, Ma; Zhongqiang, Chen

    2017-01-01

    Previous studies have reported the normative values of pelvic sagittal parameters, but no study has analyzed the sagittal spino-pelvic alignment in degenerative lumbar scoliosis (DLS) and its role in the pathogenesis. Retrospective analysis was applied to 104 patients with DLS, together with 100 cases of asymptomatic young adults as a control group and another control group consisting of 145 cases with cervical spondylosis. The coronal and sagittal parameters were measured on the anteroposterior and lateral radiograph of the whole spine in the DLS group as well as in the two control groups. Statistical analysis showed that the DLS group had a higher pelvic incidence (PI) value (50.5° ± 10.2°), than the normal control group (with PI 47.2° ± 8.8°) and the cervical spondylosis group (46.9° ± 9.1°). In DLS group, there were 38 cases (36.5%) complicated with degenerative lumbar spondylolisthesis, who had higher PI values than patients without it. Besides, the lumbar lordosis (LL) and sacral slope (SS) of DLS group were lower; the scoliosis Cobb's angle was correlated with pelvic tilt (PT); thoracic kyphosis was correlated with LL, SS, and PT; and LL was correlated with other sagittal parameters. Patients with DLS may have a higher PI, which may impact the pathogenesis of DLS. A high PI value is probably associated with the high prevalence of degenerative lumbar spondylolisthesis among DLS patients. In DLS patients, the lumbar spine maintains the ability of regulating the sagittal balance, and the regulation depends more on thoracic curve.

  15. Resistive mode in rotating plasma columns including the hall current

    International Nuclear Information System (INIS)

    Galvao, R.M.O.

    1983-01-01

    A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author) [pt

  16. Dissociating object-based from egocentric transformations in mental body rotation: effect of stimuli size.

    Science.gov (United States)

    Habacha, Hamdi; Moreau, David; Jarraya, Mohamed; Lejeune-Poutrain, Laure; Molinaro, Corinne

    2018-01-01

    The effect of stimuli size on the mental rotation of abstract objects has been extensively investigated, yet its effect on the mental rotation of bodily stimuli remains largely unexplored. Depending on the experimental design, mentally rotating bodily stimuli can elicit object-based transformations, relying mainly on visual processes, or egocentric transformations, which typically involve embodied motor processes. The present study included two mental body rotation tasks requiring either a same-different or a laterality judgment, designed to elicit object-based or egocentric transformations, respectively. Our findings revealed shorter response times for large-sized stimuli than for small-sized stimuli only for greater angular disparities, suggesting that the more unfamiliar the orientations of the bodily stimuli, the more stimuli size affected mental processing. Importantly, when comparing size transformation times, results revealed different patterns of size transformation times as a function of angular disparity between object-based and egocentric transformations. This indicates that mental size transformation and mental rotation proceed differently depending on the mental rotation strategy used. These findings are discussed with respect to the different spatial manipulations involved during object-based and egocentric transformations.

  17. Influence of implant rod curvature on sagittal correction of scoliosis deformity

    DEFF Research Database (Denmark)

    Salmingo, Remel A.; Tadano, Shigeru; Abe, Yuichiro

    2014-01-01

    of the implant rod’s angle of curvature during surgery and establish its influence on sagittal correction of scoliosis deformity. STUDY DESIGN: A retrospective analysis of the preoperative and postoperative implant rod geometry and angle of curvature was conducted. PATIENT SAMPLE: Twenty adolescent idiopathic......BACKGROUND CONTEXT: Deformation of in vivo–implanted rods could alter the scoliosis sagittal correction. To our knowledge, no previous authors have investigated the influence of implanted-rod deformation on the sagittal deformity correction during scoliosis surgery. PURPOSE: To analyze the changes...... scoliosis patients underwent surgery. Average age at the time of operation was 14 years. OUTCOME MEASURES: The preoperative and postoperative implant rod angle of curvature expressed in degrees was obtained for each patient. METHODS: Two implant rods were attached to the concave and convex side...

  18. Symmetry breaking in small rotating clouds of trapped ultracold Bose atoms

    International Nuclear Information System (INIS)

    Dagnino, D.; Barberan, N.; Riera, A.; Osterloh, K.; Lewenstein, M.

    2007-01-01

    We study the signatures of rotational and phase symmetry breaking in small rotating clouds of trapped ultracold Bose atoms by looking at rigorously defined condensate wave function. Rotational symmetry breaking occurs in narrow frequency windows, where energy degeneracy between the lowest energy states of different total angular momentum takes place. This leads to a complex condensate wave function that exhibits vortices clearly seen as holes in the density, as well as characteristic local phase patterns, reflecting the appearance of vorticities. Phase symmetry (or gauge symmetry) breaking, on the other hand, is clearly manifested in the interference of two independent rotating clouds

  19. Hybrid fixation in the bilateral sagittal split osteotomy for lower jaw advancement

    Directory of Open Access Journals (Sweden)

    Felipe Ladeira Pereira

    2010-02-01

    Full Text Available Miniplate and screw fixation has been widely used in bilateral sagittal split osteotomy, but some issues remain unclear concerning its lack of rigidity when compared to Spiessl's bicortical technique. This paper demonstrates the hybrid fixation technique in a case report. A 34-year-old female patient underwent a double jaw surgery with counter-clockwise rotation of the mandible fixed using the hybrid fixation technique. The patient evolved well in the postoperative period and is still under follow up after 14 months, reporting satisfaction with the results and no significant deviation from the treatment plan up to now. No damage to tooth roots was done, maxillomandibular range of motion was within normality and regression of the inferior alveolar nerve paresthesia was observed bilaterally. The hybrid mandibular fixation is clearly visible in the panoramic and cephalometric control radiographs. It seems that the hybrid fixation can sum the advantages of both monocortical and bicortical techniques in lower jaw advancement, increasing fixation stability without significant damage to the mandibular articulation and the inferior alveolar nerve. A statistical investigation seems necessary to prove its efficacy.

  20. Equilibrium of current driven rotating liquid metal

    International Nuclear Information System (INIS)

    Velikhov, E.P.; Ivanov, A.A.; Zakharov, S.V.; Zakharov, V.S.; Livadny, A.O.; Serebrennikov, K.S.

    2006-01-01

    In view of great importance of magneto-rotational instability (MRI) as a fundamental mechanism for angular momentum transfer in magnetized stellar accretion disks, several research centers are involved in experimental study of MRI under laboratory conditions. The idea of the experiment is to investigate the rotation dynamics of well conducting liquid (liquid metal) between two cylinders in axial magnetic field. In this Letter, an experimental scheme with immovable cylinders and fluid rotation driven by radial current is considered. The analytical solution of a stationary flow was found taking into account the external current. Results of axially symmetric numerical simulations of current driven fluid dynamics in experimental setup geometry are presented. The analytical solution and numerical simulations show that the current driven fluid rotation in axial magnetic field provides the axially homogeneous velocity profile suitable for MRI study in classical statement

  1. Precessing rotating flows with additional shear: stability analysis.

    Science.gov (United States)

    Salhi, A; Cambon, C

    2009-03-01

    We consider unbounded precessing rotating flows in which vertical or horizontal shear is induced by the interaction between the solid-body rotation (with angular velocity Omega(0)) and the additional "precessing" Coriolis force (with angular velocity -epsilonOmega(0)), normal to it. A "weak" shear flow, with rate 2epsilon of the same order of the Poincaré "small" ratio epsilon , is needed for balancing the gyroscopic torque, so that the whole flow satisfies Euler's equations in the precessing frame (the so-called admissibility conditions). The base flow case with vertical shear (its cross-gradient direction is aligned with the main angular velocity) corresponds to Mahalov's [Phys. Fluids A 5, 891 (1993)] precessing infinite cylinder base flow (ignoring boundary conditions), while the base flow case with horizontal shear (its cross-gradient direction is normal to both main and precessing angular velocities) corresponds to the unbounded precessing rotating shear flow considered by Kerswell [Geophys. Astrophys. Fluid Dyn. 72, 107 (1993)]. We show that both these base flows satisfy the admissibility conditions and can support disturbances in terms of advected Fourier modes. Because the admissibility conditions cannot select one case with respect to the other, a more physical derivation is sought: Both flows are deduced from Poincaré's [Bull. Astron. 27, 321 (1910)] basic state of a precessing spheroidal container, in the limit of small epsilon . A Rapid distortion theory (RDT) type of stability analysis is then performed for the previously mentioned disturbances, for both base flows. The stability analysis of the Kerswell base flow, using Floquet's theory, is recovered, and its counterpart for the Mahalov base flow is presented. Typical growth rates are found to be the same for both flows at very small epsilon , but significant differences are obtained regarding growth rates and widths of instability bands, if larger epsilon values, up to 0.2, are considered. Finally

  2. The longitudinal sagittal growth changes of maxilla and mandible according to quantitative cervical vertebral maturation.

    Science.gov (United States)

    Chen, Lili; Lin, Jiuxiang; Xu, Tianmin; Long, Xiaosi

    2009-04-01

    To investigate the longitudinal sagittal growth changes of maxilla and mandible according to the quantitative cervical vertebral maturation (QCVM) for adolescents with normal occlusion, mixed longitudinal data were used. The samples included 87 adolescents aged from 8 to 18 y old with normal occlusion (32 males, 55 females) selected from 901 candidates. Sequential lateral cephalograms and hand-wrist films were taken once a year, lasting for 6 y. The longitudinal sagittal growth changes of maxilla and mandible according to QCVM were measured. There were some significant differences between maxilla and mandible according to QCVM. The sagittal growth change of maxilla showed a trend towards high velocity-->decelerating velocity-->completing velocity from QCVM stage I to stage IV. The sagittal growth change of mandible showed a trend towards accelerating velocity-->high velocity-->decelerating velocity-->completing velocity from QCVM stage I to stage IV. With sagittal relationship, growth magnitude was almost the same between maxilla and mandible at QCVM stage I. At stage II the growth of mandible exceeded that of maxilla and growth in mandible continued at stages III and IV, while the maxilla ceased to grow. Growth magnitude was greater and the growth duration was longer with male mandible. It is concluded that the longitudinal sagittal growth changes of maxilla and mandible on the basis of QCVM is of value in the orthodontic practice.

  3. CONVECTIVE BURSTS AND THE COUPLING OF SATURN'S EQUATORIAL STORMS AND INTERIOR ROTATION

    International Nuclear Information System (INIS)

    Heimpel, Moritz; Aurnou, Jonathan M.

    2012-01-01

    Temporal variations of Saturn's equatorial jet and magnetic field hint at rich dynamics coupling the atmosphere and the deep interior. However, it has been assumed that rotation of the interior dynamo must be steady over tens of years of modern observations. Here we use a numerical convection model and scaling estimates to show how equatorial convective bursts can transfer angular momentum to the deeper interior. The numerical model allows angular momentum transfer between a fluid outer spherical shell and a rigid inner sphere. Convection drives a prograde equatorial jet exhibiting quasiperiodic bursts that fill the equatorial volume outside the tangent cylinder. For each burst strong changes in the equatorial surface velocity are associated with retrograde torque on the inner sphere. Our results suggest that Saturn's Great White Spot, a giant storm that was observed to fill the equatorial region in 1990, could mobilize a volume of fluid carrying roughly 15% of Saturn's moment of inertia. Conservation of angular momentum then implies that a 20% change in the equatorial jet angular velocity could change the average interior rotation rate by about 0.1%—roughly an order of magnitude less than the apparent rotation rate changes associated with Saturn's kilometric radio (SKR) signal. However, if the SKR signal originates outside the liquid metal core in a 'planetary tachocline' that separates the layer of fast zonal flow from the magnetically controlled and slowly convecting deep interior, then convective bursts can provide a possible mechanism for the observed ∼1% SKR changes.

  4. Topographic instability of flow in a rotating fluid

    Directory of Open Access Journals (Sweden)

    K. I. Patarashvili

    2006-01-01

    Full Text Available Here are presented the results of experimental and theoretical studies on a stability of zonal geostrophic flows in the rotating layer of the shallow water. In the experiments, a special apparatus by Abastumani Astrophysical Observatory Georgian Academy of Science was used. This apparatus represents a paraboloid of rotation, which can be set in a regulable rotation around the vertical axis. Maximal diameter of the paraboloid is 1.2 m, radius of curvature in the pole is 0.698 m. In the paraboloid, water spreads on walls as a layer uniform on height under the period of rotation 1.677 s. Against a background of the rotating fluid, the zonal flows are formed by the source-sink system. It consists of two concentric circular perforations on the paraboloid bottom (width is 0.3 cm, radiuses are 8.4 and 57.3 cm, respectively; water can be pumped through them with various velocities and in all directions. It has been established that under constant vertical depth of the rotating fluid the zonal flows are stable. There are given the measurements of the radial profiles for the water level and velocity in the stationary regime. It has been found that zonal flows may lose stability under the presence of the radial gradient of full depth formed by a change of angular velocity of paraboloid rotation. An instability origin results in the loss of flow axial symmetry and in the appearance of self-excited oscillations in the zonal flow. At the given angular velocity of rotation, instability is observed only in the definite range of intensities of the source-sink system. The theoretical estimations are performed in the framework of the equations of the shallow water theory, including the terms describing the bottom friction. It has been shown that the instability of zonal flows found experimentally has a topographical nature and is related with non-monotone dependence of the potential vorticity on radius.

  5. Generation of vertical angular momentum in single, double, and triple-turn pirouette en dehors in ballet.

    Science.gov (United States)

    Kim, Jemin; Wilson, Margaret A; Singhal, Kunal; Gamblin, Sarah; Suh, Cha-Young; Kwon, Young-Hoo

    2014-09-01

    The purpose of this study was to investigate the vertical angular momentum generation strategies used by skilled ballet dancers in pirouette en dehors. Select kinematic parameters of the pirouette preparation (stance depth, vertical center-of-mass motion range, initial shoulder line position, shoulder line angular displacement, and maximum trunk twist angle) along with vertical angular momentum parameters during the turn (maximum momentums of the whole body and body parts, and duration and rate of generation) were obtained from nine skilled collegiate ballet dancers through a three-dimensional motion analysis and compared among three turn conditions (single, double, and triple). A one-way ('turn') multivariate analysis of variance of the kinematic parameters and angular momentum parameters of the whole body and a two-way analysis of variance ('turn' × 'body') of the maximum angular momentums of the body parts were conducted. Significant 'turn' effects were observed in the kinematic/angular momentum parameters (both the preparation and the turn) (p <  0.05). As the number of turns increased, skilled dancers generated larger vertical angular momentums by predominantly increasing the rate of momentum generation using rotation of the upper trunk and arms. The trail (closing) arm showed the largest contribution to whole-body angular momentum followed by the lead arm.

  6. WHY ARE RAPIDLY ROTATING M DWARFS IN THE PLEIADES SO (INFRA)RED? NEW PERIOD MEASUREMENTS CONFIRM ROTATION-DEPENDENT COLOR OFFSETS FROM THE CLUSTER SEQUENCE

    Energy Technology Data Exchange (ETDEWEB)

    Covey, Kevin R. [Department of Physics and Astronomy, Western Washington University, Bellingham WA 98225-9164 (United States); Agüeros, Marcel A.; Liu, Jiyu [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Law, Nicholas M. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Ahmadi, Aida [Max Planck Institute for Radioastronomy, Auf dem Hügel 69, D-53121 Bonn (Germany); Laher, Russ; Surace, Jason [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Levitan, David [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Sesar, Branimir, E-mail: kevin.covey@wwu.edu [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2016-05-10

    Stellar rotation periods ( P {sub rot}) measured in open clusters have proved to be extremely useful for studying stars’ angular momentum content and rotationally driven magnetic activity, which are both age- and mass-dependent processes. While P {sub rot} measurements have been obtained for hundreds of solar-mass members of the Pleiades, measurements exist for only a few low-mass (<0.5 M {sub ⊙}) members of this key laboratory for stellar evolution theory. To fill this gap, we report P {sub rot} for 132 low-mass Pleiades members (including nearly 100 with M ≤ 0.45 M {sub ⊙}), measured from photometric monitoring of the cluster conducted by the Palomar Transient Factory in late 2011 and early 2012. These periods extend the portrait of stellar rotation at 125 Myr to the lowest-mass stars and re-establish the Pleiades as a key benchmark for models of the transport and evolution of stellar angular momentum. Combining our new P {sub rot} with precise BVIJHK photometry reported by Stauffer et al. and Kamai et al., we investigate known anomalies in the photometric properties of K and M Pleiades members. We confirm the correlation detected by Kamai et al. between a star's P {sub rot} and position relative to the main sequence in the cluster's color–magnitude diagram. We find that rapid rotators have redder ( V − K ) colors than slower rotators at the same V , indicating that rapid and slow rotators have different binary frequencies and/or photospheric properties. We find no difference in the photometric amplitudes of rapid and slow rotators, indicating that asymmetries in the longitudinal distribution of starspots do not scale grossly with rotation rate.

  7. Giant angular resonance and the structure of the lowest-lying nuclear states

    International Nuclear Information System (INIS)

    Mikhajlov, I.N.; Usmanov, P.N.; Yuldashbaeva, Eh.Kh.

    1987-01-01

    The analysis is given of the Hamiltonian of the two-rotor model, which is based on the assumption that the giant angular resonance exists, i.e. that it is possible to rotate the neutron component of a deformed nucleus as a whole with respect to the proton component. The realization of the projections on the intrinsic axes of the angular momentum operators is found, the Hamiltonian matrix is determined in the basis convenient for the case of strong neutron-proton coupling. The spectrum of the two-rotor model is determined taking into account the nondiagonal matrix elements in the lowest order of the perturbation theory. The g factors and the probabilities of the M1 transitions are discussed

  8. Coupled rotational dynamics of Jupiter's thermosphere and magnetosphere

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2009-01-01

    Full Text Available We describe an axisymmetric model of the coupled rotational dynamics of the thermosphere and magnetosphere of Jupiter that incorporates self-consistent physical descriptions of angular momentum transfer in both systems. The thermospheric component of the model is a numerical general circulation model. The middle magnetosphere is described by a simple physical model of angular momentum transfer that incorporates self-consistently the effects of variations in the ionospheric conductivity. The outer magnetosphere is described by a model that assumes the existence of a Dungey cycle type interaction with the solar wind, producing at the planet a largely stagnant plasma flow poleward of the main auroral oval. We neglect any decoupling between the plasma flows in the magnetosphere and ionosphere due to the formation of parallel electric fields in the magnetosphere. The model shows that the principle mechanism by which angular momentum is supplied to the polar thermosphere is meridional advection and that mean-field Joule heating and ion drag at high latitudes are not responsible for the high thermospheric temperatures at low latitudes on Jupiter. The rotational dynamics of the magnetosphere at radial distances beyond ~30 RJ in the equatorial plane are qualitatively unaffected by including the detailed dynamics of the thermosphere, but within this radial distance the rotation of the magnetosphere is very sensitive to the rotation velocity of the thermosphere and the value of the Pedersen conductivity. In particular, the thermosphere connected to the inner magnetosphere is found to super-corotate, such that true Pedersen conductivities smaller than previously predicted are required to enforce the observed rotation of the magnetosphere within ~30 RJ. We find that increasing the Joule heating at high latitudes by adding a component due to rapidly fluctuating electric fields is unable to explain the high equatorial temperatures. Adding a component of Joule

  9. ‘Lumbar Degenerative Kyphosis’ Is Not Byword for Degenerative Sagittal Imbalance: Time to Replace a Misconception

    Science.gov (United States)

    Lee, Chang-Hyun; Chung, Chun Kee; Jang, Jee-Soo; Kim, Sung-Min; Chin, Dong-Kyu; Lee, Jung-Kil

    2017-01-01

    Lumbar degenerative kyphosis (LDK) is a subgroup of the flat-back syndrome and is most commonly caused by unique life styles, such as a prolonged crouched posture during agricultural work and performing activities of daily living on the floor. Unfortunately, LDK has been used as a byword for degenerative sagittal imbalance, and this sometimes causes confusion. The aim of this review was to evaluate the exact territory of LDK, and to introduce another appropriate term for degenerative sagittal deformity. Unlike what its name suggests, LDK does not only include sagittal balance disorder of the lumbar spine and kyphosis, but also sagittal balance disorder of the whole spine and little lordosis of the lumbar spine. Moreover, this disease is closely related to the occupation of female farmers and an outdated Asian life style. These reasons necessitate a change in the nomenclature of this disorder to prevent misunderstanding. We suggest the name “primary degenerative sagittal imbalance” (PDSI), which encompasses degenerative sagittal misalignments of unknown origin in the whole spine in older-age patients, and is associated with back muscle wasting. LDK may be regarded as a subgroup of PDSI related to an occupation in agriculture. Conservative treatments such as exercise and physiotherapy are recommended as first-line treatments for patients with PDSI, and surgical treatment is considered only if conservative treatments failed. The measurement of spinopelvic parameters for sagittal balance is important prior to deformity corrective surgery. LDK can be considered a subtype of PDSI that is more likely to occur in female farmers, and hence the use of LDK as a global term for all degenerative sagittal imbalance disorders is better avoided. To avoid confusion, we recommend PDSI as a newer, more accurate diagnostic term instead of LDK. PMID:28264231

  10. SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

    Science.gov (United States)

    Greene, J. E.; Leauthaud, A.; Emsellem, E.; Ge, J.; Aragón-Salamanca, A.; Greco, J.; Lin, Y.-T.; Mao, S.; Masters, K.; Merrifield, M.; More, S.; Okabe, N.; Schneider, D. P.; Thomas, D.; Wake, D. A.; Pan, K.; Bizyaev, D.; Oravetz, D.; Simmons, A.; Yan, R.; van den Bosch, F.

    2018-01-01

    We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et al. group catalog, we identify central and satellite galaxies in groups with halo masses in the range {10}12.5 {h}-1 {M}ȯ {10}11 {h}-2 {M}ȯ tend to have very little rotation, while nearly all galaxies at lower mass show some net rotation. The ∼30% of high-mass galaxies that have significant rotation do not stand out in other galaxy properties, except for a higher incidence of ionized gas emission. Our data are consistent with recent simulation results suggesting that major merging and gas accretion have more impact on the rotational support of lower-mass galaxies. When carefully matching the stellar mass distributions, we find no residual differences in angular momentum content between satellite and central galaxies at the 20% level. Similarly, at fixed mass, galaxies have consistent rotation properties across a wide range of halo mass. However, we find that errors in classification of central and satellite galaxies with group finders systematically lower differences between satellite and central galaxies at a level that is comparable to current measurement uncertainties. To improve constraints, the impact of group-finding methods will have to be forward-modeled via mock catalogs.

  11. Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

    Science.gov (United States)

    Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

    2013-01-01

    In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided. PMID:24340276

  12. Coherent distributions for the rigid rotator

    Energy Technology Data Exchange (ETDEWEB)

    Grigorescu, Marius [CP 15-645, Bucharest 014700 (Romania)

    2016-06-15

    Coherent solutions of the classical Liouville equation for the rigid rotator are presented as positive phase-space distributions localized on the Lagrangian submanifolds of Hamilton-Jacobi theory. These solutions become Wigner-type quasiprobability distributions by a formal discretization of the left-invariant vector fields from their Fourier transform in angular momentum. The results are consistent with the usual quantization of the anisotropic rotator, but the expected value of the Hamiltonian contains a finite “zero point” energy term. It is shown that during the time when a quasiprobability distribution evolves according to the Liouville equation, the related quantum wave function should satisfy the time-dependent Schrödinger equation.

  13. Potential of mechanical metamaterials to induce their own global rotational motion

    Science.gov (United States)

    Dudek, K. K.; Wojciechowski, K. W.; Dudek, M. R.; Gatt, R.; Mizzi, L.; Grima, J. N.

    2018-05-01

    The potential of several classes of mechanical metamaterials to induce their own overall rotational motion through the individual rotation of their subunits is examined. Using a theoretical approach, we confirm that for various rotating rigid unit systems, if by design the sum of angular momentum of subunits rotating in different directions is made to be unequal, then the system will experience an overall rotation, the extent of which may be controlled through careful choice of the geometric parameters defining these systems. This phenomenon of self-induced rotation is also confirmed experimentally. Furthermore, we discuss how these systems can be designed in a special way so as to permit extended rotations which allows them to overcome geometric lockage and the relevance of this concept in applications ranging from satellites to spacecraft and telescopes employed in space.

  14. Cosmic censorship of rotating Anti-de Sitter black hole

    Energy Technology Data Exchange (ETDEWEB)

    Gwak, Bogeun; Lee, Bum-Hoon, E-mail: rasenis@sogang.ac.kr, E-mail: bhl@sogang.ac.kr [Center for Quantum Spacetime, Sogang University, Seoul 04107 (Korea, Republic of)

    2016-02-01

    We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid.

  15. Cosmic censorship of rotating Anti-de Sitter black hole

    International Nuclear Information System (INIS)

    Gwak, Bogeun; Lee, Bum-Hoon

    2016-01-01

    We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid

  16. Demonstration of pumping efficiency for rotating disks by Monte Carlo simulation

    International Nuclear Information System (INIS)

    Ogiwara, Norio

    2010-01-01

    We investigated the concept of creating a gas radial flow by employing the molecular drag effect upon gas molecules on rotating disks. All the gas molecules have a circumferential velocity rω (r: distance from the rotating axis, and ω: angular velocity) each time they leave a surface of the rotating disks. As a result, the gas molecules between the rotating disks tend on average to move outward from the center. That is, a radial flow appears. This idea was demonstrated by Monte Carlo simulation of 2 types of rotating disks (flat and corrugated ones). Pumping efficiency was clearly demonstrated for both types of disks when the velocity ratio rω/ ( : mean velocity) became larger than 1. (author)

  17. Five-dimensional rotating black hole in a uniform magnetic field: The gyromagnetic ratio

    International Nuclear Information System (INIS)

    Aliev, A.N.; Frolov, Valeri P.

    2004-01-01

    In four-dimensional general relativity, the fact that a Killing vector in a vacuum spacetime serves as a vector potential for a test Maxwell field provides one with an elegant way of describing the behavior of electromagnetic fields near a rotating Kerr black hole immersed in a uniform magnetic field. We use a similar approach to examine the case of a five-dimensional rotating black hole placed in a uniform magnetic field of configuration with biazimuthal symmetry that is aligned with the angular momenta of the Myers-Perry spacetime. Assuming that the black hole may also possess a small electric charge we construct the five-vector potential of the electromagnetic field in the Myers-Perry metric using its three commuting Killing vector fields. We show that, like its four-dimensional counterparts, the five-dimensional Myers-Perry black hole rotating in a uniform magnetic field produces an inductive potential difference between the event horizon and an infinitely distant surface. This potential difference is determined by a superposition of two independent Coulomb fields consistent with the two angular momenta of the black hole and two nonvanishing components of the magnetic field. We also show that a weakly charged rotating black hole in five dimensions possesses two independent magnetic dipole moments specified in terms of its electric charge, mass, and angular momentum parameters. We prove that a five-dimensional weakly charged Myers-Perry black hole must have the value of the gyromagnetic ratio g=3

  18. Initial results of shoulder MRI in external rotation after primary shoulder dislocation and after immobilization in external rotation

    International Nuclear Information System (INIS)

    Pennekamp, W.; Nicolas, V.; Gekle, C.; Seybold, D.

    2006-01-01

    Purpose: A change in the strategy for treating primary anterior traumatic dislocation of the shoulder has occurred. To date, brief fixation of internal rotation via a Gilchrist bandage has been used. Depending on the patient's age, a redislocation is seen in up to 90% of cases. This is due to healing of the internally rotated labrum-ligament tear in an incorrect position. In the case of external rotation of the humerus, better repositioning of the labrum ligament complex is achieved. Using MRI of the shoulder in external rotation, the extent of the improved labrum-ligament adjustment can be documented, and the indication of immobilization of the shoulder in external rotation can be derived. The aim of this investigation is to describe the degree of position changing of the labrum-ligament tear in internal and external rotation. Materials and Methods: 10 patients (9 male, 1 female, mean age 30.4 years, range 15-43 years) with a primary anterior dislocation of the shoulder without hyper laxity of the contra lateral side and labrum-ligament lesion substantiated by MRI were investigated using a standard shoulder MRI protocol (PD-TSE axial fs, PD-TSE coronar fs, T2-TSE sagittal, T1-TSE coronar) by an axial PD-TSE sequence in internal and external rotation. The dislocation and separation of the anterior labrum-ligament complex were measured. The shoulders were immobilized in 10 external rotation for 3 weeks. After 6 weeks a shoulder MRI in internal rotation was performed. Results: In all patients there was a significantly better position of the labrum-ligament complex of the inferior rim in external rotation, because of the tension of the ventral capsule and the subscapular muscle. In the initial investigation, the separation of the labrum-ligament complex in internal rotation was 0.44±0.27 mm and the dislocation was 0.45±0.33 mm. In external rotation the separation was 0.01±0.19 mm and the dislocation was -0.08±0.28 mm. After 6 weeks of immobilization in 10 external

  19. Measurement of instantaneous rotational speed using double-sine-varying-density fringe pattern

    Science.gov (United States)

    Zhong, Jianfeng; Zhong, Shuncong; Zhang, Qiukun; Peng, Zhike

    2018-03-01

    Fast and accurate rotational speed measurement is required both for condition monitoring and faults diagnose of rotating machineries. A vision- and fringe pattern-based rotational speed measurement system was proposed to measure the instantaneous rotational speed (IRS) with high accuracy and reliability. A special double-sine-varying-density fringe pattern (DSVD-FP) was designed and pasted around the shaft surface completely and worked as primary angular sensor. The rotational angle could be correctly obtained from the left and right fringe period densities (FPDs) of the DSVD-FP image sequence recorded by a high-speed camera. The instantaneous angular speed (IAS) between two adjacent frames could be calculated from the real-time rotational angle curves, thus, the IRS also could be obtained accurately and efficiently. Both the measurement principle and system design of the novel method have been presented. The influence factors on the sensing characteristics and measurement accuracy of the novel system, including the spectral centrobaric correction method (SCCM) on the FPD calculation, the noise sources introduce by the image sensor, the exposure time and the vibration of the shaft, were investigated through simulations and experiments. The sampling rate of the high speed camera could be up to 5000 Hz, thus, the measurement becomes very fast and the change in rotational speed was sensed within 0.2 ms. The experimental results for different IRS measurements and characterization of the response property of a servo motor demonstrated the high accuracy and fast measurement of the proposed technique, making it attractive for condition monitoring and faults diagnosis of rotating machineries.

  20. The angle of inclination of the native ACL in the coronal and sagittal planes.

    Science.gov (United States)

    Reid, Jonathan C; Yonke, Bret; Tompkins, Marc

    2017-04-01

    The purpose of this cross-sectional study was to evaluate the angle of inclination of the native anterior cruciate ligament (ACL) in both the sagittal and coronal planes and to evaluate these findings based on sex, height, BMI, and skeletal maturity. Inclusion criteria for the study included patients undergoing routine magnetic resonance imaging (MRI) of the knee at a single outpatient orthopedic center who had an intact ACL on MRI. Measurements of the angle of inclination were made on MRIs in both the sagittal and coronal planes. Patients were compared based on sex, height, BMI, and skeletal maturity. One-hundred and eighty-eight patients were included (36 skeletally immature/152 skeletally mature; 98 male/90 female). The overall angle of inclination was 74.3° ± 4.8° in the coronal plane and 46.9° ± 4.9° in the sagittal plane. Skeletally immature patients (coronal: 71.8° ± 6.1°; sagittal: 44.7° ± 5.5°) were significantly different in both coronal and sagittal planes (P = 0.04 and 0.01, respectively) from skeletally mature patients (coronal: 75.3° ± 4.7°; sagittal: 47.4° ± 4.7°). There were no differences based on sex, height, or BMI. There are differences between the angle of inclination findings in this study and other studies, which could be due to MRI and measurement techniques. Clinically, skeletal maturity may be important to account for when using the ACL angle of inclination to evaluate anatomic ACL reconstruction. Prognostic retrospective study, Level of evidence III.

  1. Accuracy of MR imaging in partial tears of rotator cuff

    International Nuclear Information System (INIS)

    Eto, Masao; Ito, Nobuyuki; Tomonaga, Tadashi; Harada, Shin'ichi; Rabbi, M.E.; Iwasaki, Katsuro

    1997-01-01

    MRI is very useful for the diagnosis of the rotator cuff tear However. in case of partial tears it is sometimes controvertible. In this study, we studied the accuracy of MRI in the diagnosis of partial tears. 67 patients who underwent MRI investigation before operation were chosen for this study. There were 61 males and 6 females, ranging from 30 to 80 years (mean: 54.8 years at the time of operation). MRI was performed with 1.5T superconductive system with shoulder surface coil. MPGR T2-weighted images were performed in the coronal oblique and sagittal oblique planes. Complete tears were diagnosed when full thickness high intensity was observed in the rotator cuff, whereas with partial high intensity of the rotator cuff, was considered as partial tears. MRI demonstrated 77.8% sensitivity, 91.4% specificity and 89.6% accuracy in the diagnosis of partial tear. In 8 cases MRI had misinterpretation. In MPGR T2-weighted images, not only the partial tears but the degenerative changes also show high intensity of the rotator cuff. Therefore, it is difficult to differentiate and maybe this is the reason of misinterpretations of partial tears by MRI. MRI provided with useful pre-operative informations of partial tears of the rotator cuff. However, in few cases it is hard to differentiate for the degenerative changes of the rotator cuff. (author)

  2. From stationary annular rings to rotating Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2012-04-01

    Full Text Available contributions from the two ring-slits completely overlap (evident in Fig. 1), the angular rotation is non-zero and the entire field at P3 experiences the rotation. 3. EXPERIMENTAL METHODOLOGY The experimental setup used to generate superpositions of higher...) as a ?petal?-field. The field at the ring-slit hologram (i.e., the field at plane P1), we will term the ?singularity?-field and that formed at plane P2 (a distance of 2f from lens L4) will be termed as the ?spiral?-field. 4. RESULTS AND DISCUSSION...

  3. Diffused vorticity approach to the oscillations of a rotating Bose ...

    Indian Academy of Sciences (India)

    angular velocity then tends to enlarge the rotating cloud, the centrifugal force giv- ... approximation [6], we will focus on the analysis of the most important ..... on the external boundary (see figure 3b), so that the quality of the approximation.

  4. Professional AngularJS

    CERN Document Server

    Karpov, Valeri

    2015-01-01

    A comprehensive guide to AngularJS, Google's open-source client-side framework for app development. Most of the existing guides to AngularJS struggle to provide simple and understandable explanations for more advanced concepts. As a result, some developers who understand all the basic concepts of AngularJS struggle when it comes to building more complex real-world applications. Professional AngularJS provides a thorough understanding of AngularJS, covering everything from basic concepts, such as directives and data binding, to more advanced concepts like transclusion, build systems, and auto

  5. Modes of uncontrolled rotational motion of the Progress M-29M spacecraft

    Science.gov (United States)

    Belyaev, M. Yu.; Matveeva, T. V.; Monakhov, M. I.; Rulev, D. N.; Sazonov, V. V.

    2018-01-01

    We have reconstructed the uncontrolled rotational motion of the Progress M-29M transport cargo spacecraft in the single-axis solar orientation mode (the so-called sunward spin) and in the mode of the gravitational orientation of a rotating satellite. The modes were implemented on April 3-7, 2016 as a part of preparation for experiments with the DAKON convection sensor onboard the Progress spacecraft. The reconstruction was performed by integral statistical techniques using the measurements of the spacecraft's angular velocity and electric current from its solar arrays. The measurement data obtained in a certain time interval have been jointly processed using the least-squares method by integrating the equations of the spacecraft's motion relative to the center of mass. As a result of processing, the initial conditions of motion and parameters of the mathematical model have been estimated. The motion in the sunward spin mode is the rotation of the spacecraft with an angular velocity of 2.2 deg/s about the normal to the plane of solar arrays; the normal is oriented toward the Sun or forms a small angle with this direction. The duration of the mode is several orbit passes. The reconstruction has been performed over time intervals of up to 1 h. As a result, the actual rotational motion of the spacecraft relative to the Earth-Sun direction was obtained. In the gravitational orientation mode, the spacecraft was rotated about its longitudinal axis with an angular velocity of 0.1-0.2 deg/s; the longitudinal axis executed small oscillated relative to the local vertical. The reconstruction of motion relative to the orbital coordinate system was performed in time intervals of up to 7 h using only the angularvelocity measurements. The measurements of the electric current from solar arrays were used for verification.

  6. Bio-Inspired Micro-Fluidic Angular-Rate Sensor for Vestibular Prostheses

    Directory of Open Access Journals (Sweden)

    Charalambos M. Andreou

    2014-07-01

    Full Text Available This paper presents an alternative approach for angular-rate sensing based on the way that the natural vestibular semicircular canals operate, whereby the inertial mass of a fluid is used to deform a sensing structure upon rotation. The presented gyro has been fabricated in a commercially available MEMS process, which allows for microfluidic channels to be implemented in etched glass layers, which sandwich a bulk-micromachined silicon substrate, containing the sensing structures. Measured results obtained from a proof-of-concept device indicate an angular rate sensitivity of less than 1 °/s, which is similar to that of the natural vestibular system. By avoiding the use of a continually-excited vibrating mass, as is practiced in today’s state-of-the-art gyroscopes, an ultra-low power consumption of 300 μW is obtained, thus making it suitable for implantation.

  7. Investigation of reconstruction conditions in sagittal-plane multiplanar reconstruction of the temporal bone

    International Nuclear Information System (INIS)

    Suzuki, Miyako; Yoshikawa, Hiroshi; Hosokawa, Akira; Ichikawa, Ginichiro; Kobayashi, Kenichi; Ando, Ichiro

    2002-01-01

    In recent years, it has become possible to quickly obtain a large amount of 3D data with high continuity by helical CT scanning, in which the body is scanned continuously in a helical fashion. MPR (multiplanar reconstruction) can be performed using this data to generate images in arbitrary sectional planes, making it possible to obtain sagittal-plane images of the highest quality, which is useful for surgical planning. However, the procedures involved are rather complicated. Therefore, this study was conducted to investigate conditions for standardization of sagittal-plane MPR examinations performed using Xvigor CT scanners and Xtension. The results showed that a slice interval of 1 mm, no imaging filter, a zooming factor of 1.5, a window level of 350, and a window width of 3500 are the optimal imaging conditions. The stapes can be visualized in 70% of cases with sagittal-plane MPR based on axial images, and can be recognized at surgery in 75% or more of cases. Images of consistent quality can be obtained by standardizing the conditions for sagittal-plane MPR, which should prove advantageous in the clinical setting. (author)

  8. Fragile black holes and an angular momentum cutoff in peripheral heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    McInnes, Brett, E-mail: matmcinn@nus.edu.sg [Centro de Estudios Cientificos (CECs), Valdivia (Chile); National University of Singapore (Singapore)

    2012-08-11

    In collisions of heavy ions at extremely high energies, it is possible for a significant quantity of angular momentum to be deposited into the Quark-Gluon Plasma which is thought to be produced. We develop a simple geometric model of such a system, and show that it is dual, in the AdS/CFT sense, to a rotating AdS black hole with a topologically planar event horizon. However, when this black hole is embedded in string theory, it proves to be unstable, for all non-zero angular momenta, to a certain non-perturbative effect: the familiar planar black hole, as used in most AdS/CFT analyses of QGP physics, is 'fragile'. The upshot is that the AdS/CFT duality apparently predicts that the QGP should always become unstable when it is produced in peripheral collisions. However, we argue that holography indicates that relatively low angular momenta delay the development of the instability, so that in practice it may be observable only for peripheral collisions involving favorable impact parameters, generating extremely large angular momenta. In principle, the result may be holographic prediction of a cutoff for the observable angular momenta of the QGP, or perhaps of an analogous phenomenon in condensed matter physics.

  9. Angular momentum dependence of the nuclear level density parameter

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Kailas, S.

    2010-01-01

    Dependence of nuclear level density parameter on the angular momentum and temperature is investigated in a theoretical framework using the statistical theory of hot rotating nuclei. The structural effects are incorporated by including shell correction, shape, and deformation. The nuclei around Z≅50 with an excitation energy range of 30 to 40 MeV are considered. The calculations are in good agreement with the experimentally deduced inverse level density parameter values especially for 109 In, 113 Sb, 122 Te, 123 I, and 127 Cs nuclei.

  10. Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    De Smet, A.A.; Monu, J.U.; Fisher, D.R.; Keene, J.S.; Graf, B.K.

    1992-01-01

    We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliabilty of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We indentified high signal defects of fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are usefull signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present. (orig.)

  11. Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    De Smet, A.A.; Monu, J.U.; Fisher, D.R. (Univ. of Wisconsin Hospital and Clinics, Dept. of Radiology, Madison, WI (United States)); Keene, J.S.; Graf, B.K. (Univ. of Wisconsin Hospital and Clinics, Div. of Orthopedic Surgery, Madison, WI (United States))

    1992-02-01

    We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliabilty of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We indentified high signal defects of fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are usefull signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present. (orig.).

  12. The rotate-plus-shift C-arm trajectory. Part I. Complete data with less than 180° rotation

    International Nuclear Information System (INIS)

    Ritschl, Ludwig; Fleischmann, Christof; Kuntz, Jan; Kachelrieß, Marc

    2016-01-01

    Purpose: In the last decade, C-arm-based cone-beam CT became a widely used modality for intraoperative imaging. Typically a C-arm CT scan is performed using a circular or elliptical trajectory around a region of interest. Therefore, an angular range of at least 180° plus fan angle must be covered to ensure a completely sampled data set. However, mobile C-arms designed with a focus on classical 2D applications like fluoroscopy may be limited to a mechanical rotation range of less than 180° to improve handling and usability. The method proposed in this paper allows for the acquisition of a fully sampled data set with a system limited to a mechanical rotation range of at least 180° minus fan angle using a new trajectory design. This enables CT like 3D imaging with a wide range of C-arm devices which are mainly designed for 2D imaging. Methods: The proposed trajectory extends the mechanical rotation range of the C-arm system with two additional linear shifts. Due to the divergent character of the fan-beam geometry, these two shifts lead to an additional angular range of half of the fan angle. Combining one shift at the beginning of the scan followed by a rotation and a second shift, the resulting rotate-plus-shift trajectory enables the acquisition of a completely sampled data set using only 180° minus fan angle of rotation. The shifts can be performed using, e.g., the two orthogonal positioning axes of a fully motorized C-arm system. The trajectory was evaluated in phantom and cadaver examinations using two prototype C-arm systems. Results: The proposed trajectory leads to reconstructions without limited angle artifacts. Compared to the limited angle reconstructions of 180° minus fan angle, image quality increased dramatically. Details in the rotate-plus-shift reconstructions were clearly depicted, whereas they are dominated by artifacts in the limited angle scan. Conclusions: The method proposed here employs 3D imaging using C-arms with less than 180° rotation

  13. The rotate-plus-shift C-arm trajectory. Part I. Complete data with less than 180° rotation

    Energy Technology Data Exchange (ETDEWEB)

    Ritschl, Ludwig; Fleischmann, Christof [Ziehm Imaging GmbH, Donaustraße 31, Nürnberg 90451 (Germany); Kuntz, Jan, E-mail: j.kuntz@dkfz.de; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany)

    2016-05-15

    Purpose: In the last decade, C-arm-based cone-beam CT became a widely used modality for intraoperative imaging. Typically a C-arm CT scan is performed using a circular or elliptical trajectory around a region of interest. Therefore, an angular range of at least 180° plus fan angle must be covered to ensure a completely sampled data set. However, mobile C-arms designed with a focus on classical 2D applications like fluoroscopy may be limited to a mechanical rotation range of less than 180° to improve handling and usability. The method proposed in this paper allows for the acquisition of a fully sampled data set with a system limited to a mechanical rotation range of at least 180° minus fan angle using a new trajectory design. This enables CT like 3D imaging with a wide range of C-arm devices which are mainly designed for 2D imaging. Methods: The proposed trajectory extends the mechanical rotation range of the C-arm system with two additional linear shifts. Due to the divergent character of the fan-beam geometry, these two shifts lead to an additional angular range of half of the fan angle. Combining one shift at the beginning of the scan followed by a rotation and a second shift, the resulting rotate-plus-shift trajectory enables the acquisition of a completely sampled data set using only 180° minus fan angle of rotation. The shifts can be performed using, e.g., the two orthogonal positioning axes of a fully motorized C-arm system. The trajectory was evaluated in phantom and cadaver examinations using two prototype C-arm systems. Results: The proposed trajectory leads to reconstructions without limited angle artifacts. Compared to the limited angle reconstructions of 180° minus fan angle, image quality increased dramatically. Details in the rotate-plus-shift reconstructions were clearly depicted, whereas they are dominated by artifacts in the limited angle scan. Conclusions: The method proposed here employs 3D imaging using C-arms with less than 180° rotation

  14. Noninvasive Optoelectronic Assessment of Induced Sagittal Imbalance Using the Vicon System.

    Science.gov (United States)

    Ould-Slimane, Mourad; Latrobe, Charles; Michelin, Paul; Chastan, Nathalie; Dujardin, Franck; Roussignol, Xavier; Gauthé, Rémi

    2017-06-01

    Spinal diseases often induce gait disorders with multifactorial origins such as lumbar pain, radicular pain, neurologic complications, or spinal deformities. However, radiography does not permit an analysis of spinal dynamics; therefore, sagittal balance dynamics during gait remain largely unexplored. This prospective and controlled pilot study assessed the Vicon system for detecting sagittal spinopelvic imbalance, to determine the correlations between optoelectronic and radiographic parameters. Reversible anterior sagittal imbalance was induced in 24 healthy men using a thoracolumbar corset. Radiographic, optoelectronic, and comparative analyses were conducted. Corset wearing induced significant variations in radiographic parameters indicative of imbalance; the mean C7-tilt and d/D ratio increased by 15° ± 7.4° and 359%, respectively, whereas the mean spinosacral angle decreased by 16.8° ± 8° (all P imbalance; the mean spinal angle increased by 15.4° ± 5.6° (P imbalance detected using the Vicon system. Optoelectronic C7'S1' correlated with radiographic C7-tilt and d/D ratio. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. A previously unreported variant of the synostotic sagittal suture: Case report and review of salient literature

    Directory of Open Access Journals (Sweden)

    Madison Budinich

    2016-12-01

    Full Text Available Introduction: Sagittal synostosis is a rare congenital disease caused by the premature fusion of the sagittal suture. Craniosynostosis occurs for a variety of reasons, different for every case, and often the etiology is unclear but the anomaly can frequently be seen as part of Crouzon's or Apert's syndromes. Herein, we discuss a rare case of craniosynostosis where the patient presented with a, to our knowledge, a previously undescribed variant of sagittal synostosis. Case report: A 3-month-old female infant presented to a craniofacial clinic for a consultation regarding an abnormal head shape. Images of the skull were performed, demonstrating that the patient had craniosynostosis. The patient displayed no other significant symptoms besides abnormalities in head shape. The sagittal suture was found to extend into the occipital bone where it was synostotic. Conclusion: To our knowledge, a synostotic sagittal suture has not been reported that extended posteriorly it involve the occipital bone. Those who interpret imaging or operate on this part of the skull should consider such a variation. Keywords: Anatomy, Craniosynostosis, Skull, Malformation, Pediatrics

  16. The signature of atmospheric tides in sub-daily variations of Earth rotation as unveiled by globally-gridded atmospheric angular momentum functions

    Science.gov (United States)

    Schindelegger, M.; Böhm, J.; Salstein, D. A.; Schuh, H.

    2012-12-01

    Thermally-driven atmospheric tides provide a small but distinct contribution to shortperiod variations of Earth rotation parameters (ERP). The effect of diurnal and semi-diurnal tides, commonly denoted as S1 and S2, respectively, is in the range of 2 - 10 uas for polar motion and 2 - 10 uas for changes in length-of-day (LOD). Even though ocean tides represent a much more dominant driving agent for ERP fluctuations at short time scales, high-frequency atmospheric effects are non-negligible, particularly given the prospective measurement accuracy of space geodetic techniques. However, previous studies, such as Brzezinski et al. (2002), de Viron et al. (2005) or Schindelegger et al. (2011), have been noticeably inconclusive on the exact amplitude and phase values of S1 and S2 atmospheric excitation signals. This study aims at shedding light on the origin of these uncertainties with respect to the axial component of Earth's rotation vector by investigating times series of atmospheric angular momentum (AAM) functions that are given on global grids and computed from three-hourly meteorological data of the European Centre for Medium-Range Weather Forecasts (ECMWF). The signature of diurnal and semi-diurnal atmospheric tides is clearly visible in the gridded axial AAM functions, revealing a distinct spatial and temporal phase difference between pressure and wind tidal constituents of about ± π. It is shown that due to this counterbalance and the explicit axisymmetric spatial structure of S1 and S2, the net effect in sub-diurnal AAM (which is calculated from the global sum of gridded AAM functions) is always a small quantity, particularly sensitive to minor differences between the analysis fields of numerical weather models.

  17. Benefits of sagittal-oblique MRI reconstruction of anterior cruciate ligament of the knee

    International Nuclear Information System (INIS)

    Nenezić, D.

    2015-01-01

    Full text: MRI examination of the anterior cruciate ligament (ACL) of the knee gives valuable information for conventional, physiatrist and/or arthroscopic microinvasiv treatment. three planar MRI examination and 3D reconstructions are highly precise in the analysis of the intra and periarticular structures, with exceptions of anterior cruciate ligament. Direct contact with the roof of the intercondilar fossa (in the full extension during the examination) and its specific orientation makes visualization of ACL diagnostically problematic. In a one year period precise protocol for MRI visualization of ACL was tested and applied as “Sagittal Oblique MRI Reconstruction”. In short, it has been Angled biplanar reconstruction in the parasagital and paratransversal planes (patientrelated and arbitrary selected in full extension), on T2, 2mm slice and 0,2 mm gap. 153 MRI examinations of the patients with lesions of the ACL were included in the study in the Clinical Center of Montenegro during 2005 year. Beside standard Knee MRI protocol all patients had the Sagittal Oblique MRI reconstruction of ACL and the Flexion MRI examination, to compare with. The Sagittal Oblique MRI reconstruction of ACL it is adapted to the concrete morphology of the patients ACL and it does not depend of the volume of the examined knee. In comparison with the Standard Knee MRI protocol and with the Flexion MRI examination, the Sagittal Oblique MRI reconstruction of ACL takes less time to perform, and the ligament is shown in fool length at three to five slices, which is more than with the both compared protocols. Sagittal Oblique MRI Reconstruction of ACL is therefore patient dependable, orientated in shape of concrete ligament of the patient’s knee. In combination with age, occupation, physical activity and level of patients while to contribute in healing process, the Sagittal Oblique MRI reconstruction of ACL contribute to scholastic approach, as highest benefit to patients with

  18. INFLUENCE OF THE SAGITTAL BALANCE ON THE CLINICAL OUTCOME IN SPINAL FUSION

    Directory of Open Access Journals (Sweden)

    Marcela Almeida Campos Coutinho

    2016-03-01

    Full Text Available ABSTRACT Objective: Evaluates which radiographic parameters of the sagittal and spinopelvic balance influence the clinical and functional outcomes of a sample of patients undergoing spinal fusion. Methods: We studied 32 patients who underwent spinal fusion. Radiographs of the total spine were obtained from all patients. The clinical and functional parameters studied were analysis of pain by visual analogic scale (VAS and Oswestry and SRS-30 questionnaires. We analyzed the correlation between the clinical and functional parameters and radiographic parameters of the sagittal and spinopelvic balance. Results: There was no significant correlation between parameters pelvic incidence (PI, pelvic tilt (PT, lumbar lordosis (LL and difference between PI and LL (PI-LL and clinical parameters (p > 0.05 and r <0.2. Significant correlation were identified only between Sagittal Vertical Axis (SVA and Satisfaction with Treatment domain of SRS-30 (r = 0.402 e p = 0.023 and between thoracic kyphosis (TK and the total SRS-30 (r = 0.419 and p = 0.017. Conclusions: According to the study results, it was not possible to precisely characterize the role of the parameters of the sagittal and spinopelvic balance in the post-operative analysis of the clinical outcome of spinal fusion. There was a significant correlation only between SVA and the Satisfaction with Treatment domain of SRS-30 and between TK and total SRS-30.

  19. Tracking errors in tractography of the gastrocnemius muscle. A comparison between the transverse and sagittal planes

    International Nuclear Information System (INIS)

    Aoki, Takako; Tohdoh, Yukihiro; Tawara, Noriyuki; Okuwaki, Toru; Horiuchi, Akira; Itagaki, Takuma; Niitsu, Mamoru

    2010-01-01

    In scans taken in conventional direction, tracking errors may occur when using a streamline-based algorithm for the tractography of the gastrocnemius muscle. To solve errors in tracking, we applied tractography to the musculotendinous junction and performed fiber tracking on the gastrocnemius muscle of 10 healthy subjects with their written informed consent. We employed a spin-echo diffusion tensor imaging (SE-DTI) sequence with 6-direction diffusion gradient sensitization and acquired DTI images at 1.5 tesla using a body array coil with parallel imaging. We compared tractography obtained in the transverse and sagittal planes using anatomical reference and found that the gastrocnemius muscle and musculotendinous junction were significantly better visualized on sagittal scans and in 3 regions of interest. We utilized Mann-Whitney U-test to determine significant differences between rates of concordance (P 2 value of skeletal muscle is around 50 ms, and TE should be as short as possible. A streamline-based algorithm is based on the continuity of a vector. It is easy to take running of the muscle fiber in sagittal scan. Therefore, tracking error is hard to occur. In conclusion, sagittal scanning may be one way to eliminate tracking errors in the tractography of the gastrocnemius muscle. Tracking errors were smaller with sagittal scans than transverse scans, and sagittal scans allow better fiber tracking. (author)

  20. Measurement of product rotational alignment in associative-ionization collisions between polarized Na(3p) atoms

    International Nuclear Information System (INIS)

    Wang, M.; de Vries, M.S.; Weiner, J.

    1986-01-01

    We have studied the effect of reactant Na(3p) polarization on the rotational angular momentum alignment of product Na 2 + ions arising from associative-ionization (AI) collisions. Our results show that sensitivity of the AI rate constant to initial atomic polarization persists even when all hyperfine states are populated with broadband (3 cm -1 ) pulsed laser excitation of Na( 2 P/sub 3/2/) and that the spatial distribution of product rotational angular momentum vectors is anisotropic. We discuss a qualitative description of the collision process consistent with our measurements which indicates that sigma-orbital symmetry is preferred to π-orbital symmetry as the colliding partners approach

  1. Investigation of first ray mobility during gait by kinematic fluoroscopic imaging-a novel method

    Directory of Open Access Journals (Sweden)

    Martin Heiner

    2012-02-01

    Full Text Available Abstract Background It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane. Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing. Methods Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait. Results Total flexion of the first ray was found to be 13.63 (SD 6.14 mm with the healthy volunteers and 13.06 (SD 8.01 mm with the patients (resolution: 0.245 mm/pixel. The dorsiflexion angle was 5.27 (SD 2.34 degrees in the healthy volunteers and increased to 5.56 (SD 3.37 degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups. Conclusions Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait. A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found.

  2. A Microscopic Quantal Model for Nuclear Collective Rotation

    International Nuclear Information System (INIS)

    Gulshani, P.

    2007-01-01

    A microscopic, quantal model to describe nuclear collective rotation in two dimensions is derived from the many-nucleon Schrodinger equation. The Schrodinger equation is transformed to a body-fixed frame to decompose the Hamiltonian into a sum of intrinsic and rotational components plus a Coriolis-centrifugal coupling term. This Hamiltonian (H) is expressed in terms of space-fixed-frame particle coordinates and momenta by using commutator of H with a rotation angle. A unified-rotational-model type wavefunction is used to obtain an intrinsic Schrodinger equation in terms of angular momentum quantum number and two-body operators. A Hartree-Fock mean-field representation of this equation is then obtained and, by means of a unitary transformation, is reduced to a form resembling that of the conventional semi-classical cranking model when exchange terms and intrinsic spurious collective excitation are ignored

  3. Quadrupole collective excitations in rapidly rotating nuclej

    International Nuclear Information System (INIS)

    Mikhajlov, I.N.

    1983-01-01

    The spectrum of collective quadrupole excitations in nuclei is investigated. The average nucleus field has the axial symmetry and rotation occurs relatively to this axis. Dependences of the spectrum of quadrupole oscillations on rotation rate for classic liquid drop (CLD) and for a drop of fermi-liquid (DFL) with fissionability parameter X=0.62 ( 154 Er) are presented. The dependence of probabilities of E2-transitions between single-phonon and phonon-free states on rotation rate for CLD and DFL with fussionability parameter X=0.62 ( 154 Er) is also presented. It is shown that for CLD collective E2-transition of states of yrast-consequence is absolutely forbidden. For DFL transitions are possible that lead to decay of phonon-free state with the excitation of phonons of γ-modes and decrease of angular momentum

  4. The accuracy of intramedullary tibial guide of sagittal alignment of PCL-substituting total knee arthroplasty.

    Science.gov (United States)

    Han, Hyuk-Soo; Kang, Seung-Baik; Jo, Chris H; Kim, Sun-Hong; Lee, Jung-Ha

    2010-10-01

    Experimental and clinical studies on the accuracy of the intramedullary alignment method have produced different results, and few have addressed accuracy in the sagittal plane. Reported deviations are not only attributable to the alignment method but also to radiological errors. The purpose of this study was to evaluate the accuracy of the intramedullary alignment method in the sagittal plane using computed tomography (CT) and 3-dimensional imaging software. Thirty-one TKAs were performed using an intramedullary alignment method involving the insertion of a long 8-mm diameter rod into the medullary canal to the distal metaphysis of the tibia. All alignment instruments were set to achieve an ideal varus/valgus angle of 0° in the coronal plane and a tibial slope of 0° in the sagittal plane. The accuracy of the intramedullary alignment system was assessed by measuring the coronal tibial component angle and sagittal tibial slope angles, i.e., angles between the tibial anatomical axis and the tangent to the medial and lateral tibial plateau or the cut-surface. The mean coronal tibial component angle was 88.5° ± 1.2° and the mean tibial component slope in the sagittal plane was 1.6° ± 1.2° without anterior slope. Our intramedullary tibial alignment method, which involves passing an 8-mm diameter long rod through the tibial shaft isthmus, showed good accuracy (less than 3 degrees of variation and no anterior slope) in the sagittal plane in neutral or varus knees.

  5. Conjoined lumbosacral nerve roots compromised by disk herniation: sagittal shoulder sign for the preoperative diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chang Ho [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Korea University College of Medicine, Department of Radiology, Anam Hospital, Seoul (Korea); Shin, Myung Jin; Kim, Sung Moon; Lee, Sang Hoon; Kim, Hee Kyung; Ryu, Jeong Ah [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Lee, Choon-Sung [University of Ulsan College of Medicine, Asan Medical Center, Department of Orthopedic Surgery, Seoul (Korea); Kim, Sam Soo [Kangwon National University College of Medicine, Department of Radiology, Kangwon (Korea)

    2008-03-15

    The objective was to determine the importance of the ''sagittal shoulder sign'' on magnetic resonance (MR) images for the diagnosis of conjoined lumbosacral nerve roots (CLNR) that are compromised by herniated disks. Magnetic resonance images of 11 patients (6 men and 5 women; age range, 25-71 years; average age, 48.7 years) with surgically proven CLNR, which was compromised by herniated disks, were retrospectively evaluated by two musculoskeletal radiologists. MR images were evaluated for the presence or absence of the sagittal shoulder sign - a vertical structure connecting two consecutive nerve roots and overlying disk on the sagittal MR images. The radiologists noted the type of accompanying disk herniation and bony spinal canal changes, as well as other characteristic MR features of CLNR, the common passage of two consecutive nerve roots through the neural foramen on axial MR images. The sagittal shoulder sign was identified with a mean frequency of 90.9% by the two observers (in 10 of 11 patients). The common passage of two consecutive nerve roots through the neural foramen on axial MR images was identified with a mean frequency of 59.1% (in 7 and 6 out of 11 patients, by observers 1 and 2, respectively). Good interobserver agreement for the sagittal shoulder sign was present (k = 0.621, p < 0.05). Observation of the sagittal shoulder sign may prove helpful for diagnosing CLNR in patients with disk herniation. In particular, this sign appears to be useful when there is no evidence of CLNR on axial MR images. (orig.)

  6. Study of the mode of angular velocity damping for a spacecraft at non-standard situation

    Science.gov (United States)

    Davydov, A. A.; Sazonov, V. V.

    2012-07-01

    Non-standard situation on a spacecraft (Earth's satellite) is considered, when there are no measurements of the spacecraft's angular velocity component relative to one of its body axes. Angular velocity measurements are used in controlling spacecraft's attitude motion by means of flywheels. The arising problem is to study the operation of standard control algorithms in the absence of some necessary measurements. In this work this problem is solved for the algorithm ensuring the damping of spacecraft's angular velocity. Such a damping is shown to be possible not for all initial conditions of motion. In the general case one of two possible final modes is realized, each described by stable steady-state solutions of the equations of motion. In one of them, the spacecraft's angular velocity component relative to the axis, for which the measurements are absent, is nonzero. The estimates of the regions of attraction are obtained for these steady-state solutions by numerical calculations. A simple technique is suggested that allows one to eliminate the initial conditions of the angular velocity damping mode from the attraction region of an undesirable solution. Several realizations of this mode that have taken place are reconstructed. This reconstruction was carried out using approximations of telemetry values of the angular velocity components and the total angular momentum of flywheels, obtained at the non-standard situation, by solutions of the equations of spacecraft's rotational motion.

  7. Uncertainty principle for angular position and angular momentum

    International Nuclear Information System (INIS)

    Franke-Arnold, Sonja; Barnett, Stephen M; Yao, Eric; Leach, Jonathan; Courtial, Johannes; Padgett, Miles

    2004-01-01

    The uncertainty principle places fundamental limits on the accuracy with which we are able to measure the values of different physical quantities (Heisenberg 1949 The Physical Principles of the Quantum Theory (New York: Dover); Robertson 1929 Phys. Rev. 34 127). This has profound effects not only on the microscopic but also on the macroscopic level of physical systems. The most familiar form of the uncertainty principle relates the uncertainties in position and linear momentum. Other manifestations include those relating uncertainty in energy to uncertainty in time duration, phase of an electromagnetic field to photon number and angular position to angular momentum (Vaccaro and Pegg 1990 J. Mod. Opt. 37 17; Barnett and Pegg 1990 Phys. Rev. A 41 3427). In this paper, we report the first observation of the last of these uncertainty relations and derive the associated states that satisfy the equality in the uncertainty relation. We confirm the form of these states by detailed measurement of the angular momentum of a light beam after passage through an appropriate angular aperture. The angular uncertainty principle applies to all physical systems and is particularly important for systems with cylindrical symmetry

  8. Molecular resonances in 28SI + 28Si - Wobbling motions observed by angular correlation measurements

    International Nuclear Information System (INIS)

    Uegaki, E.; Abe, Y.

    2014-01-01

    High-spin resonances observed in 28 Si+ 28 Si collisions are studied with a dinuclear molecular model. At high spins, a stable dinuclear configuration of the oblate-oblate system ( 28 Si+ 28 Si) is found to be an equator-equator (E-E) touching one. Normal modes have been investigated around the equilibrium, which are expected to be an origin of a large number of the resonances observed. Analyses of physical quantities are made and compared with the recent experimental data measured at Strasbourg. Since the E-E configuration is slightly triaxial, rotations of the total system induce mixing of K quantum numbers, called wobbling motion, which clearly explains the particle-γ angular correlations observed as well as the misalignments observed in the angular distributions, in a simple and natural way. Furthermore, predictions are given for the angular correlations of the wobbling excited states. The importance of the angular correlation measurements is stressed, which provide identification of the dinuclear configurations by spin orientations of the constituent nuclei 28 Si. (authors)

  9. Discrete time interval measurement system: fundamentals, resolution and errors in the measurement of angular vibrations

    International Nuclear Information System (INIS)

    Gómez de León, F C; Meroño Pérez, P A

    2010-01-01

    The traditional method for measuring the velocity and the angular vibration in the shaft of rotating machines using incremental encoders is based on counting the pulses at given time intervals. This method is generically called the time interval measurement system (TIMS). A variant of this method that we have developed in this work consists of measuring the corresponding time of each pulse from the encoder and sampling the signal by means of an A/D converter as if it were an analog signal, that is to say, in discrete time. For this reason, we have denominated this method as the discrete time interval measurement system (DTIMS). This measurement system provides a substantial improvement in the precision and frequency resolution compared with the traditional method of counting pulses. In addition, this method permits modification of the width of some pulses in order to obtain a mark-phase on every lap. This paper explains the theoretical fundamentals of the DTIMS and its application for measuring the angular vibrations of rotating machines. It also displays the required relationship between the sampling rate of the signal, the number of pulses of the encoder and the rotating velocity in order to obtain the required resolution and to delimit the methodological errors in the measurement

  10. The angular momentum-mass relation: a fundamental law from dwarf irregulars to massive spirals

    Science.gov (United States)

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

    2018-05-01

    In a Λ CDM Universe, the specific stellar angular momentum (j*) and stellar mass (M*) of a galaxy are correlated as a consequence of the scaling existing for dark matter haloes (jh ∝2/3). The shape of this law is crucial to test galaxy formation models, which are currently discrepant especially at the lowest masses, allowing to constrain fundamental parameters, such as, for example, the retained fraction of angular momentum. In this study, we accurately determine the empirical j*-M* relation (Fall relation) for 92 nearby spiral galaxies (from S0 to Irr) selected from the Spitzer Photometry and Accurate Rotation Curves (SPARC) sample in the unprecedented mass range 7 ≲ log M*/M⊙≲ 11.5. We significantly improve all previous estimates of the Fall relation by determining j* profiles homogeneously for all galaxies, using extended HI rotation curves, and selecting only galaxies for which a robust j* could be measured (converged j*(http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/L6

  11. Long-Period Tidal Variations of the Earth's Rotation Rate

    Science.gov (United States)

    Desai, S.; Gross, R.; Wahr, J.

    1999-01-01

    Long-period tidal variations of the Earth's rotation rate are caused by the redistribution of mass associated with the respective elastic solid Earth tides, the ocean tide heights, and the anelasticity of the Earth's mantle, and by the relative angular momentum associated with the long-period ocean tide currents.

  12. Cavity-enhanced Faraday rotation measurement with auto-balanced photodetection.

    Science.gov (United States)

    Chang, Chia-Yu; Shy, Jow-Tsong

    2015-10-01

    Optical cavity enhancement for a tiny Faraday rotation is demonstrated with auto-balanced photodetection. This configuration is analyzed using the Jones matrix formalism. The resonant rotation signal is amplified, and thus, the angular sensitivity is improved. In the experiment, the air Faraday rotation is measured with an auto-balanced photoreceiver in single-pass and cavity geometries. The result shows that the measured Faraday rotation in the single-pass geometry is enhanced by a factor of 85 in the cavity geometry, and the sensitivity is improved to 7.54×10(-10)  rad Hz(-1/2), which agrees well with the Jones matrix analysis. With this verification, we propose an AC magnetic sensor whose magnetic sensitivity is expected to achieve 10  pT Hz(-1/2).

  13. A study of human performance in a rotating environment

    Science.gov (United States)

    Green, J. A.; Peacock, J. L.; Holm, A. P.

    1971-01-01

    Consideration is given to the lack of sufficient data relative to the response of man to the attendant oculovestibular stimulations induced by multi-directional movement of an individual within the rotating environment to provide the required design criteria. This was done to determine the overall impact of artificial gravity simulations on potential design configurations and crew operational procedures. Gross locomotion and fine motor performance were evaluated. Results indicate that crew orientation, rotational rates, vehicle design configurations, and operational procedures may be used to reduce the severity of the adverse effects of the Coriolis and cross-coupled angular accelerations acting on masses moving within a rotating environment. Results further indicate that crew selection, motivation, and short-term exposures to the rotating environment may be important considerations for future crew indoctrination and training programs.

  14. The structure of rotational discontinuities. [in solar wind

    Science.gov (United States)

    Neugebauer, M.

    1989-01-01

    This study examines the structures of a set of rotational discontinuities detected in the solar wind by the ISEE-3 spacecraft. It is found that the complexity of the structure increases as the angle theta between the propagation vector k and the magnetic field decreases. For rotational discontinuities that propagate at a large angle to the field with an ion (left-hand) sense of rotation, the magnetic hodograms tend to be flattened, in agreement with prior numerical simulations. When theta is large, angular 'overshoots' are often observed at one or both ends of the discontinuity. When the propagation is nearly parallel to the field (when theta is small), many different types of structure are seen, ranging from straight lines, to S-shaped curves, to complex, disorganized shapes.

  15. Electromagnetic fields of rotating magnetized NUT stars

    International Nuclear Information System (INIS)

    Ahmedov, B.J.; Khugaev, A.V.; Ahmedov, B.J.

    2004-01-01

    Full text: Analytic general relativistic expressions for the electromagnetic fields external to a slowly-rotating magnetized NUT star with nonvanishing gravitomagnetic charge have been presented. Solutions for the electric and magnetic fields have been found after separating the Maxwell equations in the external background spacetime of a slowly rotating NUT star into angular and radial parts in the lowest order approximation. The star is considered isolated and in vacuum, with different models for stellar magnetic field: i) monopolar magnetic field and II) dipolar magnetic field aligned with the axis of rotation. We have shown that the general relativistic corrections due to the dragging of reference frames and gravitomagnetic charge are not present in the form of the magnetic fields but emerge only in the form of the electric fields. In particular, we have shown that the frame-dragging and gravitomagnetic charge provide an additional induced electric field which is analogous to the one introduced by the rotation of the star in the flat spacetime limit

  16. Rotation-Enabled 7-Degree of Freedom Seismometer for Geothermal Resource Development. Phase 1 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, Bob [Applied Technology Associates, Albuquerque, NM (United States); Laughlin, Darren [Applied Technology Associates, Albuquerque, NM (United States)

    2013-10-29

    , and confidence, thus removing some current blocks to feasibility and significantly increasing access to potential geothermal sites. During the Phase 1 effort summarized in this final report, the ATA Team modeled and built two TRL 3 proof-of-concept test units for two competing rotational sensor technologies. The two competing technologies were based on ATA's angular rate and angular displacement measurement technologies; Angular rate: ATA's Magnetohydrodynamic Angular Rate Sensor (Seismic MHD); and Angular displacement: ATA's Low Frequency Improved Torsional Seismometer (LFITS). In order to down-select between these two technologies and formulate a go / no go decision, the ATA Team analyzed and traded scientific performance requirements and market constraints against sensor characteristics and components, acquiring field data where possible to validate the approach and publishing results from these studies of rotational technology capability. Based on the results of Phase 1, the ATA Team finds that the Seismic MHD (SMHD) technology is the best choice for enabling rotational seismometry and significant technical potential exists for micro-seismic monitoring using a downhole 7-DOF device based on the SMHD. Recent technical papers and field data confirm the potential of rotational sensing for seismic mapping, increasing confidence that cost-reduction benefits are achievable for EGS. However, the market for geothermal rotational sensing is small and undeveloped. As a result, this report recommends modifying the Phase 2 plan to focus on prototype development aimed at partnering with early adopters within the geothermal industry and the scientific research community. The highest public benefit will come from development and deployment of a science-grade SMHD rotational seismometer engineered for geothermal downhole conditions and an integrated test tool for downhole measurements at active geothermal test sites.

  17. Not all sagittal band tears come with extensor instability. A case report with radiological and operative correlation

    International Nuclear Information System (INIS)

    Li, Shuo; Jacob, Jubin; Ghasemiesfe, Ahmadreza; Marrinan, Greg B.; Brooks, Jeffrey J.

    2018-01-01

    The sagittal bands are a component of the extensor hood. They serve an important role in stabilizing the extensor tendon by forming a ''check-rein'' to radial-ulnar translation of the tendon over the metacarpal head, and extending the metacarpophalangeal (MCP) joint by virtue of attaching the extensor tendon to the palmar plate. Injury to the sagittal band is thought to cause extensor instability and subluxation to the contralateral side by disruption of this ''check-rein'' function, although recent evidence from cadaver studies suggests that ulnar sagittal band tear may be spared of extensor instability. As a case in point, we encountered a patient with surgically proven ulnar sagittal band tear, who did not have any extensor tendon subluxation or any limitation in motion. Intraoperative findings demonstrated a chronic-appearing ulnar sagittal band tear, indicating that chronic injury with fibrosis may stabilize the central band. Therefore, in patients with metacarpophalangeal pain without central tendon subluxation or limitation of motion, it remains important to raise the concern of sagittal band tear for appropriate treatment. We present the clinical course of this case, with radiological and operative findings, followed by a review of the relevant literature. (orig.)

  18. Not all sagittal band tears come with extensor instability. A case report with radiological and operative correlation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo; Jacob, Jubin; Ghasemiesfe, Ahmadreza; Marrinan, Greg B. [Yale New Haven Health Bridgeport Hospital, Bridgeport, CT (United States); Brooks, Jeffrey J. [Orthopedic Surgery and Sports Medicine Center, New Canaan, CT (United States)

    2018-04-15

    The sagittal bands are a component of the extensor hood. They serve an important role in stabilizing the extensor tendon by forming a ''check-rein'' to radial-ulnar translation of the tendon over the metacarpal head, and extending the metacarpophalangeal (MCP) joint by virtue of attaching the extensor tendon to the palmar plate. Injury to the sagittal band is thought to cause extensor instability and subluxation to the contralateral side by disruption of this ''check-rein'' function, although recent evidence from cadaver studies suggests that ulnar sagittal band tear may be spared of extensor instability. As a case in point, we encountered a patient with surgically proven ulnar sagittal band tear, who did not have any extensor tendon subluxation or any limitation in motion. Intraoperative findings demonstrated a chronic-appearing ulnar sagittal band tear, indicating that chronic injury with fibrosis may stabilize the central band. Therefore, in patients with metacarpophalangeal pain without central tendon subluxation or limitation of motion, it remains important to raise the concern of sagittal band tear for appropriate treatment. We present the clinical course of this case, with radiological and operative findings, followed by a review of the relevant literature. (orig.)

  19. Automated and angular time-synchronized directional gamma-ray scintillation sensor

    International Nuclear Information System (INIS)

    Kronenberg, S.; Brucker, G.J.

    1998-01-01

    The authors' previous research resulted in directional sensors for gamma rays and X rays that have a 4π solid angle of acceptance and, at the same time, a high angular resolution that is limited only by their ability to measure small angles. Angular resolution of ∼1 s of arc was achieved. These sensors are capable of operating and accurately detecting high and very low intensity radiation patterns. Such a system can also be used to image broad area sources and their scattering patterns. The principle of operation and design of directional sensors used in this study was described elsewhere; however, for convenience, a part of that text is repeated here. It was shown analytically that the angular distribution of radiation incident on the sensor is proportional to the first derivative of the scan data, that is, of the events' count rate versus orientation of the detector. The previously published results were obtained with a annual operating system. The detector assembly was set at a specific angle, and a pulse rate count was made. This was repeated at numerous other angles of orientation, a time-consuming and labor-intensive process. Recently, the authors automated this system, which is based on the detection of scintillations. The detector, which consists of a stack of plates of Lucite, plastic scintillator, and lead foils, rotates by means of a motor in front of a stationary photomultiplier tube (PMT). One revolution per second was chosen for the motor. At time zero, a trigger indicates that a revolution has started. The angle of orientation of the detector in the laboratory system is proportional to the time during one revolution. The process repeats itself a desired number of times. The trigger signal initiates a scan of a multichannel scalar (MCS). The detector assembly is allowed to rotate in the radiation field, and the MCS scans are repeated in an accumulated mode of operation until enough events are collected for the location of the radiation source to be

  20. Macroscopic angular momentum states of Bose-Einstein condensates in toroidal traps

    International Nuclear Information System (INIS)

    Benakli, M.; Raghavan, S.; Fantoni, S.; Shenoy, S.R.; Smerzi, A.

    1997-11-01

    We consider a Bose-Einstein condensate (BEC) of N atoms of repulsive interaction ∼ U 0 , in an elliptical trap, axially pierced by a Gaussian-intensity laser beam, forming an effective (quasi-2D) toroidal trap with minimum at radial distance ρ = ρ p . The macroscopic angular momentum states Ψ l (ρ,θ) ∼ √NΦ l (ρ)e ilθ for integer l spread up to ρ max ∼ (NU 0 ) 1/4 >> ρ p . The spreading lowers rotational energies, so estimated low metastability barriers can support large l max ∼ (NU 0 ) 1/4 , l (ρ) 2 -Φ 0 (ρ) 2 is a signature of BEC rotation. Results are insensitive to off-axis laser displacements ρ 0 , for ρ 0 ρ max << 1. (author)

  1. The relationship between changes of cervical sagittal alignment after anterior cervical discectomy and fusion and spino-pelvic sagittal alignment under roussouly classification: a four-year follow-up study.

    Science.gov (United States)

    Huang, Dong-Ning; Yu, Miao; Xu, Nan-Fang; Li, Mai; Wang, Shao-Bo; Sun, Yu; Jiang, Liang; Wei, Feng; Liu, Xiao-Guang; Liu, Zhong-Jun

    2017-02-20

    Anterior cervical discectomy and fusion (ACDF) is widely used in the treatment of cervical degenerative disease; however, the variation of cervical sagittal alignment changes after ACDF has been rarely explored. The purpose of this study is to determine the relationship between changes of cervical sagittal alignment after ACDF and spino-pelvic sagittal alignment under Roussouly classification. A cohort of 133 Chinese cervical spondylotic patients who received ACDF from 2011 to 2012 was recruited. All patients were categorized with Roussouly Classification. Lateral X-ray images of global spine were obtained, and preoperative and postoperative parameters were measured and analyzed, including C2-C7 angles (C2-C7), C0-C7 angles (C0-C7), external auditory meatus (EAM) tilt, sacral slope (SS), thoracic kyphosis (TK), lumbar lordosis (LL), spinal sacral angles (SSA), Superior adjacent inter-vertebral angle (SAIV), inferior adjacent inter-vertebral angle (IAIV) and et al. The Wilcoxon signed-rank test was used for intragroup comparisons preoperatively and at postoperative 48 months. Among the parameters, C2-C7 and C0-C7 showed significant increase, while EAM TK, and IAIV decreased significantly. In type I, EAM and TK decreased significantly, however SS showed a significant increase; in type II, TK showed a significant decrease, but SSA showed a significant increase; in type III, a significant increase of C0-C7 was observed with a significant decrease in EAM, nevertheless, LL, SS and SSA showed significant decreases; and in type IV, C2-C7 showed a significant increase and EAM decreased significantly. The percentage of lordotic alignment in cervical spine increased, which was presenting in type I, III and IV. Nevertheless, the amount of patients with straight cervical alignment increased in type II. The backward movement of head occurs is the compensatory mechanism in cervical sagittal alignment modifications after ACDF. The compensatory alteration of spino-pelvic sagittal

  2. The relationship between changes of cervical sagittal alignment after anterior cervical discectomy and fusion and spino-pelvic sagittal alignment under roussouly classification: a four-year follow-up study

    Directory of Open Access Journals (Sweden)

    Dong-Ning Huang

    2017-02-01

    Full Text Available Abstract Background Anterior cervical discectomy and fusion (ACDF is widely used in the treatment of cervical degenerative disease; however, the variation of cervical sagittal alignment changes after ACDF has been rarely explored. The purpose of this study is to determine the relationship between changes of cervical sagittal alignment after ACDF and spino-pelvic sagittal alignment under Roussouly classification. Methods A cohort of 133 Chinese cervical spondylotic patients who received ACDF from 2011 to 2012 was recruited. All patients were categorized with Roussouly Classification. Lateral X-ray images of global spine were obtained, and preoperative and postoperative parameters were measured and analyzed, including C2–C7 angles (C2–C7, C0–C7 angles (C0–C7, external auditory meatus (EAM tilt, sacral slope (SS, thoracic kyphosis (TK, lumbar lordosis (LL, spinal sacral angles (SSA, Superior adjacent inter-vertebral angle (SAIV, inferior adjacent inter-vertebral angle (IAIV and et al. The Wilcoxon signed-rank test was used for intragroup comparisons preoperatively and at postoperative 48 months. Results Among the parameters, C2–C7 and C0–C7 showed significant increase, while EAM TK, and IAIV decreased significantly. In type I, EAM and TK decreased significantly, however SS showed a significant increase; in type II, TK showed a significant decrease, but SSA showed a significant increase; in type III, a significant increase of C0–C7 was observed with a significant decrease in EAM, nevertheless, LL, SS and SSA showed significant decreases; and in type IV, C2–C7 showed a significant increase and EAM decreased significantly. The percentage of lordotic alignment in cervical spine increased, which was presenting in type I, III and IV. Nevertheless, the amount of patients with straight cervical alignment increased in type II. Conclusion The backward movement of head occurs is the compensatory mechanism in cervical sagittal alignment

  3. The gyrotron - a natural source of high-power orbital angular momentum millimeter-wave beams

    Science.gov (United States)

    Thumm, M.; Sawant, A.; Choe, M. S.; Choi, E. M.

    2017-08-01

    Orbital angular momentum (OAM) of electromagnetic-wave beams provides further diversity to multiplexing in wireless communication. The present report shows that higher-order mode gyrotrons are natural sources of high-power OAM millimeter (mm) wave beams. The well-defined OAM of their rotating cavity modes operating at near cutoff frequency has been derived by photonic and electromagnetic wave approaches.

  4. Quantitative Microstructural Characterization of Thick Aluminum Plates Heavily Deformed Using Equal Channel Angular Extrusion

    DEFF Research Database (Denmark)

    Mishin, Oleg; Segal, V.M.; Ferrasse, S.

    2012-01-01

    A detailed quantitative analysis of the microstructure has been performed in three orthogonal planes of 15-mm-thick aluminum plates heavily deformed via two equal channel angular extrusion (ECAE) routes. One route was a conventional route A with no rotation between passes. Another route involved...... sequential 90 deg rotations about the normal direction (ND) between passes. The microstructure in the center of these plates, and especially the extent of microstructural heterogeneity, has been characterized quantitatively and compared with that in bar samples extruded via either route A or route Bc with 90...... Bc. © The Minerals, Metals & Materials Society and ASM International 2012...

  5. Rotation Detection Using the Precession of Molecular Electric Dipole Moment

    Science.gov (United States)

    Ke, Yi; Deng, Xiao-Bing; Hu, Zhong-Kun

    2017-11-01

    We present a method to detect the rotation by using the precession of molecular electric dipole moment in a static electric field. The molecular electric dipole moments are polarized under the static electric field and a nonzero electric polarization vector emerges in the molecular gas. A resonant radio-frequency pulse electric field is applied to realize a 90° flip of the electric polarization vector of a particular rotational state. After the pulse electric field, the electric polarization vector precesses under the static electric field. The rotation induces a shift in the precession frequency which is measured to deduce the angular velocity of the rotation. The fundamental sensitivity limit of this method is estimated. This work is only a proposal and does not involve experimental results.

  6. Accuracy of the sagittal vertical axis in a standing lateral radiograph as a measurement of balance in spinal deformities

    NARCIS (Netherlands)

    van Royen, B.J.; Toussaint, H.M.; Kingma, I.; Bot, S.D.M.; Caspers, M.; Harlaar, J.

    1998-01-01

    Sagittal balance of the spine is becoming an important issue in the assessment of the degree of spinal deformity. On a standing lateral full- length radiograph of the spine, the plumb line, or sagittal vertical axis (SVA), can be used to determine the spinal sagittal balance. In this procedure

  7. Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella.

    Science.gov (United States)

    Aksahin, Ertugrul; Aktekin, Cem Nuri; Kocadal, Onur; Duran, Semra; Gunay, Cüneyd; Kaya, Defne; Hapa, Onur; Pepe, Murad

    2017-10-01

    The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis. Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis. The mean age of all participants was 52.9 ± 8.2 years. The mean P-PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models. This study revealed that sagittal plain malpositioning of the

  8. Formation of protostars in collapsing, rotating, turbulent clouds

    International Nuclear Information System (INIS)

    Regev, O.; Shaviv, G.

    1981-01-01

    Collapse and star formation processes in rotating turbulent interstellar gas clouds have been studied. For this purpose numerical collapse calculations have been performed for a number of representative cases. These calculations have been carried out by a two-dimensional hydrodynamical computer code, which solves the equations of hydrodynamics explicitly, coupled to the Poisson equation. The computer code has been written especially for this work and has been thoroughly tested. The calculations in this work have been performed with an effort to obtain physically reliable results (by repeating the same calculations with different numerical spatial resolutions). A physical mechanism for angular momentum transport by turbulent viscosity has been proposed and incorporated in new collapse calculations. The main results can be summerized as follows: When there is no physical mechanism for angular momentum transport, the result of the collaps is a ringlike structure. The turbulent viscosity affects the nature of the collaps. For the two cases studied, the mass of the central object is a major fraction (30%) of the total mass of the system. The exact form of the central object and its ultimate fate depend on the parameters, especially rotational energy/gravitational energy and Re. The present calculations cannot predict the future evolution of the central object. In the new theoretical model proposed, a central protostar forms as a result of the collaps of a protostellar rotating cloud

  9. An inventory on rotational kinematics of a particle: unravelling misconceptions and pitfalls in reasoning

    International Nuclear Information System (INIS)

    Mashood, K K; Singh, Vijay A

    2012-01-01

    Student difficulties regarding the angular velocity and angular acceleration of a particle have remained relatively unexplored in contrast to their linear counterparts. We present an inventory comprising multiple choice questions aimed at probing misconceptions and eliciting ill-suited reasoning patterns. The development of the inventory was based on interactions with students, teachers and experts. We report misconceptions, some of which are parallel to those found earlier in linear kinematics. Fixations with inappropriate prototypes were uncovered. Many students and even teachers mistakenly assume that all rotational motion is necessarily circular. A persistent notion that the direction of angular velocity and angular acceleration should be ‘along’ the motion exists. Instances of indiscriminate usage of equations were identified. (paper)

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

    Science.gov (United States)

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

    2013-01-21

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

  11. Effects of rotation on the evolution of primordial stars

    Science.gov (United States)

    Ekström, S.; Meynet, G.; Chiappini, C.; Hirschi, R.; Maeder, A.

    2008-10-01

    Context: Although still beyond our observational abilities, Population III stars are interesting objects from many perspectives. They are responsible for the re-ionisation of the inter-galactic medium. They also left their chemical imprint in the early Universe, which can be deciphered in the most metal-poor stars in the halo of our Galaxy. Aims: Rotation has been shown to play a determinant role at very low metallicity, bringing heavy mass loss where almost none was expected. Is this still true when the metallicity strictly equals zero? The aim of our study is to answer this question, and to determine how rotation changes the evolution and the chemical signature of the primordial stars. Methods: We have calculated seven differentially-rotating stellar models at zero metallicity, with masses between 9 and 200 M⊙. For each mass, we also calculated a corresponding model without rotation. The evolution is followed up to the pre-supernova stage. Results: We find that Z=0 models rotate with an internal profile Ω(r) close to local angular momentum conservation, because of a very weak core-envelope coupling. Rotational mixing drives an H-shell boost due to a sudden onset of the CNO cycle in the shell. This boost leads to a high 14N production, which can be as much as 106 times higher than the production of the non-rotating models. Generally, the rotating models produce much more metal than their non-rotating counterparts. The mass loss is very low, even for the models that reach critical velocity during the main sequence. It may however have an impact on the chemical enrichment of the Universe, because some of the stars are supposed to collapse directly into black holes. They would contribute to the enrichment only through their winds. While in that case non-rotating stars would not contribute at all, rotating stars may leave an imprint on their surrounding. Due to the low mass loss and the weak coupling, the core retains a high angular momentum at the end of the

  12. M Dwarf Rotation from the K2 Young Clusters to the Field. I. A Mass-Rotation Correlation at 10 Myr

    Science.gov (United States)

    Somers, Garrett; Stauffer, John; Rebull, Luisa; Cody, Ann Marie; Pinsonneault, Marc

    2017-12-01

    Recent observations of the low-mass (0.1-0.6 {M}⊙ ) rotation distributions of the Pleiades and Praesepe clusters have revealed a ubiquitous correlation between mass and rotation, such that late M dwarfs rotate an order-of-magnitude faster than early M dwarfs. In this paper, we demonstrate that this mass-rotation correlation is present in the 10 Myr Upper Scorpius association, as revealed by new K2 rotation measurements. Using rotational evolution models, we show that the low-mass rotation distribution of the 125 Myr Pleiades cluster can only be produced if it hosted an equally strong mass-rotation correlation at 10 Myr. This suggests that physical processes important in the early pre-main sequence (PMS; star formation, accretion, disk-locking) are primarily responsible for the M dwarf rotation morphology, and not quirks of later angular momentum (AM) evolution. Such early mass trends must be taken into account when constructing initial conditions for future studies of stellar rotation. Finally, we show that the average M star loses ˜25%-40% of its AM between 10 and 125 Myr, a figure accurately and generically predicted by modern solar-calibrated wind models. Their success rules out a lossless PMS and validates the extrapolation of magnetic wind laws designed for solar-type stars to the low-mass regime at early times.

  13. B polarization of the CMB from Faraday rotation

    International Nuclear Information System (INIS)

    Scoccola, Claudia; Harari, Diego; Mollerach, Silvia

    2004-01-01

    We study the effect of Faraday rotation due to a uniform magnetic field on the polarization of the cosmic microwave background. Scalar fluctuations give rise only to parity-even E-type polarization of the cosmic microwave background. However in the presence of a magnetic field, a nonvanishing parity-odd B-type polarization component is produced through Faraday rotation. We derive the exact solution for the E and B modes generated by scalar perturbations including the Faraday rotation effect of a uniform magnetic field, and evaluate their cross correlations with temperature anisotropies. We compute the angular autocorrelation function of the B-modes in the limit that the Faraday rotation is small. We find that uniform primordial magnetic fields of present strength around B 0 =10 -9 G rotate E-modes into B-modes with amplitude comparable to those due to the weak gravitational lensing effect at frequencies around ν=30 GHz. The strength of B-modes produced by Faraday rotation scales as B 0 /ν 2 . We evaluate also the depolarizing effect of Faraday rotation upon the cross correlation between temperature anisotropy and E-type polarization

  14. Nonlinear electromagnetic gyrokinetic equations for rotating axisymmetric plasmas

    International Nuclear Information System (INIS)

    Artun, M.; Tang, W.M.

    1994-03-01

    The influence of sheared equilibrium flows on the confinement properties of tokamak plasmas is a topic of much current interest. A proper theoretical foundation for the systematic kinetic analysis of this important problem has been provided here by presented the derivation of a set of nonlinear electromagnetic gyrokinetic equations applicable to low frequency microinstabilities in a rotating axisymmetric plasma. The subsonic rotation velocity considered is in the direction of symmetry with the angular rotation frequency being a function of the equilibrium magnetic flux surface. In accordance with experimental observations, the rotation profile is chosen to scale with the ion temperature. The results obtained represent the shear flow generalization of the earlier analysis by Frieman and Chen where such flows were not taken into account. In order to make it readily applicable to gyrokinetic particle simulations, this set of equations is cast in a phase-space-conserving continuity equation form

  15. THE ANGULAR MOMENTUM OF MAGNETIZED MOLECULAR CLOUD CORES: A TWO-DIMENSIONAL-THREE-DIMENSIONAL COMPARISON

    International Nuclear Information System (INIS)

    Dib, Sami; Csengeri, Timea; Audit, Edouard; Hennebelle, Patrick; Pineda, Jaime E.; Goodman, Alyssa A.; Bontemps, Sylvain

    2010-01-01

    In this work, we present a detailed study of the rotational properties of magnetized and self-gravitating dense molecular cloud (MC) cores formed in a set of two very high resolution three-dimensional (3D) MC simulations with decaying turbulence. The simulations have been performed using the adaptative mesh refinement code RAMSES with an effective resolution of 4096 3 grid cells. One simulation represents a mildly magnetically supercritical cloud and the other a strongly magnetically supercritical cloud. We identify dense cores at a number of selected epochs in the simulations at two density thresholds which roughly mimic the excitation densities of the NH 3 (J - K) = (1,1) transition and the N 2 H + (1-0) emission line. A noticeable global difference between the two simulations is the core formation efficiency (CFE) of the high-density cores. In the strongly supercritical simulations, the CFE is 33% per unit free-fall time of the cloud (t ff,cl ), whereas in the mildly supercritical simulations this value goes down to ∼6 per unit t ff,cl . A comparison of the intrinsic specific angular momentum (j 3D ) distributions of the cores with the specific angular momentum derived using synthetic two-dimensional (2D) velocity maps of the cores (j 2D ) shows that the synthetic observations tend to overestimate the true value of the specific angular momentum by a factor of ∼8-10. We find that the distribution of the ratio j 3D /j 2D of the cores peaks at around ∼0.1. The origin of this discrepancy lies in the fact that contrary to the intrinsic determination of j which sums up the individual gas parcels' contributions to the angular momentum, the determination of the specific angular momentum using the standard observational procedure which is based on a measurement on the global velocity gradient under the hypothesis of uniform rotation smoothes out the complex fluctuations present in the 3D velocity field. Our results may well provide a natural explanation for the

  16. Production of various sizes and some properties of beryllium pebbles by the rotating electrode method

    Energy Technology Data Exchange (ETDEWEB)

    Iwadachi, T.; Sakamoto, N.; Nishida, K. [NGK Insulators Ltd., Nagoya (Japan); Kawamura, H.

    1998-01-01

    The particle size distribution of beryllium pebbles produced by the rotating electrode method was investigated. Particle size depends on some physical properties and process parameters, which can practicaly be controlled by varying electrode angular velocities. The average particle sizes produced were expressed by the hyperbolic function with electrode angular velocity. Particles within the range of 0.3 and 2.0 mm in diameter are readily produced by the rotating electrode method while those of 0.2 mm in diameter are also fabricable. Sphericity and surface roughness were good in each size of pebble. Grain sizes of the pebbles are 17 {mu} m in 0.25 mm diameter pebbles and 260 {mu} m in 1.8 mm diameter pebbles. (author)

  17. Earth rotation measured by lunar laser ranging

    Science.gov (United States)

    Stolz, A.; Bender, P. L.; Faller, J. E.; Silverberg, E. C.; Mulholland, J. D.; Shelus, P. J.; Williams, J. G.; Carter, W. E.; Currie, D. G.; Kaula, V. M.

    1976-01-01

    The estimated median accuracy of 194 single-day determinations of the earth's angular position in space is 0.7 millisecond (0.01 arc second). Comparison with classical astronomical results gives agreement to about the expected 2-millisecond uncertainty of the 5-day averages obtained by the Bureau International de l'Heure. Little evidence for very rapid variations in the earth's rotation is present in the data.

  18. A dissipative model of solar system and stability of stationary rotations

    Science.gov (United States)

    Vilke, V. G.

    2009-04-01

    In classical model of Solar system the planets are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely rigid spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of mass occurs to constant angular velocity. The motion of the centers of mass of spherical planets identically to motion in the appropriate problem of points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the shape: there is "flattening" of a planet in a direction of a vector of its angular velocity and formation of tidal bulgs on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of mass of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates has been obtained. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own rotation of planets, and the small tidal deformations arising under influence of gradients of gravitational forces. The method of division of movements

  19. Perception of self motion during and after passive rotation of the body around an earth-vertical axis.

    Science.gov (United States)

    Sinha, N; Zaher, N; Shaikh, A G; Lasker, A G; Zee, D S; Tarnutzer, A A

    2008-01-01

    We investigated the perception of self-rotation using constant-velocity chair rotations. Subjects signalled self motion during three independent tasks (1) by pushing a button when rotation was first sensed, when velocity reached a peak, when velocity began to decrease, and when velocity reached zero, (2) by rotating a disc to match the perceived motion of the body, or (3) by changing the static position of the dial such that a bigger change in its position correlated with a larger perceived velocity. All three tasks gave a consistent quantitative measure of perceived angular velocity. We found a delay in the time at which peak velocity of self-rotation was perceived (2-5 s) relative to the beginning or to the end of chair rotation. In addition the decay of the perception of self-rotation was preceded by a sensed constant-velocity interval or plateau (9-14 s). This delay in the rise of self-motion perception, and the plateau for the maximum perceived velocity, contrasts with the rapid rise and the immediate decay of the angular vestibuloocular reflex (aVOR). This difference suggests that the sensory signal from the semicircular canals undergoes additional neural processing, beyond the contribution of the velocity-storage mechanism of the aVOR, to compute the percept of self-motion.

  20. Superior sagittal sinus thrombosis: a rare complication in a child with nephrotic syndrome

    International Nuclear Information System (INIS)

    Pirogovsky, A.; Adi, M.; Barzilai, N.; Dagan, A.; Sinai, L.; Sthoeger, D.; Tabachnik, E.

    2001-01-01

    A 2-year-old boy with new-onset nephrotic syndrome developed recurrent vomiting, apathy and papilloedema. Superior sagittal sinus thrombosis was diagnosed on cranial CT and MRI. He gradually recovered after treatment with heparin, fresh frozen plasma and warfarin with complete resolution of the thrombosis after 1 month. Superior sagittal sinus thrombosis is an extremely rare complication of nephrotic syndrome in children. Early diagnosis is essential for institution of anticoagulation therapy and a successful outcome. (orig.)

  1. Superior sagittal sinus thrombosis: a rare complication in a child with nephrotic syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Pirogovsky, A.; Adi, M.; Barzilai, N. [Dept. of Radiology, Kaplan Medical Center, Rehovot (Israel); Dagan, A.; Sinai, L.; Sthoeger, D. [Div. of Paediatrics, Kaplan Medical Center, Rehovot (Israel); Tabachnik, E. [Div. of Paediatrics, Kaplan Medical Center, Rehovot (Israel); Paediatric ICU, Kaplan Hospital, Rehovot (Israel)

    2001-10-01

    A 2-year-old boy with new-onset nephrotic syndrome developed recurrent vomiting, apathy and papilloedema. Superior sagittal sinus thrombosis was diagnosed on cranial CT and MRI. He gradually recovered after treatment with heparin, fresh frozen plasma and warfarin with complete resolution of the thrombosis after 1 month. Superior sagittal sinus thrombosis is an extremely rare complication of nephrotic syndrome in children. Early diagnosis is essential for institution of anticoagulation therapy and a successful outcome. (orig.)

  2. Stellar Evolution with Rotation: Mixing Processes in AGB Stars

    Science.gov (United States)

    Driebe, T.; Blöcker, T.

    We included diffusive angular momentum transport and rotationally induced mixing processes in our stellar evolution code and studied the influence of rotation on the evolution of intermediate mass stars (M*=2dots6 Msolar) towards and along the asymptotic giant branch (AGB). The calculations start in the fully convective pre-main sequence phase and the initial angular momentu m was adjusted such that on the zero-age main sequence vrot=200 km/ s is achieved. The diffusion coefficients for the five rotational instabilities considered (dynamical shear, secular shear, Eddington-Sweet (ES) circulation, Solberg-Høiland-instability and Goldreich-Schubert-Fricke (GSF) instability) were adopted from Heger et al. (2000, ApJ 528, 368). Mixing efficiency and sensitivity of these processes against molecular weight gradients have been determined by calibration of the main sequence width. In this study we focus on the abundance evolution of carbon. On the one hand, the surface abundance ratios of 12C/13C a nd 12C/16O at the base of the AGB were found to be ≈ 7dots 10 and ≈ 0.1, resp., being a factor of two lower than in non-rotating models. This results from the slow but continuously operating rotationally induced mixing due to the ES-circulation and the GSF-instability during the long main sequence phase. On the other hand, 13C serves as neutron source for interior s-process nucleosynthesis in AGB stars vi a 13C(α,n)16O. Herwig et al. (1997, A&A 324, L81) found that a 13C pocket is forme d in the intershell region of 3 Msolar AGB star if diffusive overshoot is considered. Our calculations show, that mixing processes due to rotation open an alternative channel for the formation of a 13C pocket as found by Langer et al. (1999, A&A 346, L37). Again, ES-circulation and GSF-instability are the predominant rotational mixing processes.

  3. Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis

    Science.gov (United States)

    Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

    1996-01-01

    The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

  4. Does Shoe Collar Height Influence Ankle Joint Kinematics and Kinetics in Sagittal Plane Maneuvers?

    Science.gov (United States)

    Yang, Yang; Fang, Ying; Zhang, Xini; He, Junliang; Fu, Weijie

    2017-01-01

    The Objective of the study is to investigate the effects of basketball shoes with different collar heights on ankle kinematics and kinetics and athletic performance in different sagittal plane maneuvers. Twelve participants who wore high-top and low-top basketball shoes (hereafter, HS and LS, respectively) performed a weight-bearing dorsiflexion (WB-DF) maneuver, drop jumps (DJs), and lay-up jumps (LJs). Their sagittal plane kinematics and ground reaction forces were recorded using the Vicon motion capture system and Kistler force plates simultaneously. Moreover, ankle dorsiflexion and plantarflexion angles, moment, power, stiffness, and jump height were calculated. In the WB-DF test, the peak ankle dorsiflexion angle (p = 0.041) was significantly smaller in HS than in LS. Additionally, the peak ankle plantarflexion moment (p = 0.028) and power (p = 0.022) were significantly lower in HS than in LS during LJs but not during DJs. In both jumping maneuvers, no significant differences were found in the jump height or ankle kinematics between the two shoe types. According to the WB-DF test, increasing shoe collar height can effectively reduce the ankle range of motion in the sagittal plane. Although the HS did not restrict the flexion–extension performance of the ankle joint during two jumping maneuvers, an increased shoe collar height can reduce peak ankle plantarflexion moment and peak power during the push-off phase in LJs. Therefore, a higher shoe collar height should be used to circumvent effects on the partial kinetics of the ankle joint in the sagittal plane. Key points An increased shoe collar height effectively reduced ankle joint ROM in the sagittal plane in weight-bearing dorsiflexion maneuver. Shoe collar height did not affect sagittal plane ankle kinematics and had no effect on performance during realistic jumping. Shoe collar height can affect the ankle plantarflexion torque and peak power during the push-off phase in lay-up jump. PMID:29238255

  5. Diffusion coefficients of Fokker-Planck equation for rotating dust grains in a fusion plasma

    Science.gov (United States)

    Bakhtiyari-Ramezani, M.; Mahmoodi, J.; Alinejad, N.

    2015-11-01

    In the fusion devices, ions, H atoms, and H2 molecules collide with dust grains and exert stochastic torques which lead to small variations in angular momentum of the grain. By considering adsorption of the colliding particles, thermal desorption of H atoms and normal H2 molecules, and desorption of the recombined H2 molecules from the surface of an oblate spheroidal grain, we obtain diffusion coefficients of the Fokker-Planck equation for the distribution function of fluctuating angular momentum. Torque coefficients corresponding to the recombination mechanism show that the nonspherical dust grains may rotate with a suprathermal angular velocity.

  6. Sagittal alignment and complications following lumbar 3-column osteotomy: does the level of resection matter?

    Science.gov (United States)

    Ferrero, Emmanuelle; Liabaud, Barthelemy; Henry, Jensen K; Ames, Christopher P; Kebaish, Khaled; Mundis, Gregory M; Hostin, Richard; Gupta, Munish C; Boachie-Adjei, Oheneba; Smith, Justin S; Hart, Robert A; Obeid, Ibrahim; Diebo, Bassel G; Schwab, Frank J; Lafage, Virginie

    2017-11-01

    OBJECTIVE Three-column osteotomy (3CO) is a demanding technique that is performed to correct sagittal spinal malalignment. However, the impact of the 3CO level on pelvic or truncal sagittal correction remains unclear. In this study, the authors assessed the impact of 3CO level and postoperative apex of lumbar lordosis on sagittal alignment correction, complications, and revisions. METHODS In this retrospective study of a multicenter spinal deformity database, radiographic data were analyzed at baseline and at 1- and 2-year follow-up to quantify spinopelvic alignment, apex of lordosis, and resection angle. The impact of 3CO level and apex level of lumbar lordosis on the sagittal correction was assessed. Logistic regression analyses were performed, controlling for cofounders, to investigate the effects of 3CO level and apex level on intraoperative and postoperative complications as well as on the need for subsequent revision surgery. RESULTS A total of 468 patients were included (mean age 60.8 years, mean body mass index 28.1 kg/m 2 ); 70% of patients were female. The average 3CO resection angle was 25.1° and did not significantly differ with regard to 3CO level. There were no significant correlations between the 3CO level and amount of sagittal vertical axis or pelvic tilt correction. The postoperative apex level significantly correlated with greater correction of pelvic tilt (2° per more caudal level, R = -0.2, p = 0.006). Lower-level 3CO significantly correlated with revisions for pseudarthrosis (OR = 3.88, p = 0.001) and postoperative motor deficits (OR = 2.02, p = 0.026). CONCLUSIONS In this study, a more caudal lumbar 3CO level did not lead to greater sagittal vertical axis correction. The postoperative apex of lumbar lordosis significantly impacted pelvic tilt. 3CO levels that were more caudal were associated with more postoperative motor deficits and revisions.

  7. Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns.

    Science.gov (United States)

    Steenen, S A; Becking, A G

    2016-07-01

    An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  8. Influence of the sagittal anatomy of the pelvis on the intercrestal line position.

    Science.gov (United States)

    Horduna, M; Legaye, J

    2008-03-01

    The line joining the two iliac crests is classically regarded as the anatomical landmark determining the inter-vertebral space L4-L5 for the spinal punctures. Its variability has been reported but never related to predictive clinical anatomic factors identifying patients groups in which there is increased risk of miscalculation of the spinal level. Two sagittal pelvic anatomical angles, called 'pelvic incidence' and 'pelvic lordosis' were measured on lateral X-rays of the pelvis of 132 normal individuals and 49 spondylolysis patients. The values were compared with the sagittal projection of the intercrestal line on the disco-vertebral lumbar structures. A strict relation was observed between this projection of the intercrestal line and the sagittal pelvic anatomical angles. The greater the pelvic incidence, the higher the intercrestal line was projected, all the more in patients with spondylolysis with a listhesis or a disc narrowing. The relation between the pelvic sagittal angles and the intercrestal line projection explains the variability described for this anatomical landmark. It implies precautions minimizing neurological risk in the case of a puncture carried out more cranially than expected, particularly for high values of pelvic incidence occurring in spinal pathologies such as spondylolysis, in the elderly or in the obese patients. In these cases, we recommend the use of spinal imaging during the procedure to assist selection of the desired insertion level.

  9. Determination of angular rotation velocity of Dar'e wind turbine with straight blades

    International Nuclear Information System (INIS)

    Ershina, A.K.; Ershin, Sh.A.; Upnanov, T.K.

    1999-01-01

    In the report the method of angular velocity determination for wind turbine of given capacity with allowing for an average seasonal wind velocity and all geometrical and dynamical characteristics of the unit is presented. It is noted, that this wind turbine has following advantages: wind direction does not plays role due to vertical axis position of the turbine; electric generator and other equipment are arranged on the ground, that reduce construction's weight, expedite of servicing and repair; the wind turbine has high coefficient of wind energy use (ξ max =0.45)

  10. The rotating dyonic black holes of Kaluza-Klein theory

    International Nuclear Information System (INIS)

    Rasheed, D.

    1995-01-01

    The most general electrically and magnetically charged rotating black hole solutions of 5 dimensional Kaluza-Klein theory are given in an explicit form. Various classical quantities associated with the black holes are derived. In particular, one finds the very surprising result that the gyromagnetic and gyroelectric ratios can become arbitrarily large. The thermodynamic quantities of the black holes are calculated and a Smarr-type formula is obtained leading to a generalized first law of black hole thermodynamics. The properties of the extreme solutions are investigated and it is shown how they naturally separate into two classes. The extreme solutions in one class are found to have two unusual properties: (i) Their event horizons have zero angular velocity and yet they have non-zero ADM angular momentum. (ii) In certain circumstances it is possible to add angular momentum to these extreme solutions without changing the mass or charges and yet still maintain an extreme solution. Regarding the extreme black holes as elementary particles, their stability is discussed and it is found that they are stable provided they have sufficient angular momentum. (orig.)

  11. Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

    International Nuclear Information System (INIS)

    Oudih, M.R.; Fellah, M.; Allal, N.H.; Benhamouda, N.

    1999-01-01

    It is well established that the BCS wave-functions are neither eigen-functions of the particle-number operator nor of the angular momentum operator. In a previous paper, we have developed a particle-number projection before variation method (of FBCS type). This discrete projection method is based on the SBCS wave-function. The aim of the present contribution is to perform a subsequent angular momentum projection by means of the Peierls-Yoccoz method. The general expression of the system energy, after the double projection, is established in the case of axial symmetry. For practical calculations, an approximation method is introduced. It leads to a semi-classical form of the rotational energy. The rotational spectra have been evaluated numerically for some even-even rare-earth nuclei. The single-particle energies and eigen-states are those of a deformed Woods-Saxon mean field. The obtained results are compared on one hand, to the experimental data, and on the other hand, to the theoretical spectra evaluated by a particle-number projection after variation method (of PBCS type). For all studied nuclei, the spectra determined by the FBCS method reproduce the experimental data better than those of the PBCS method. However, even if the present method is satisfying for low angular momenta, the agreement with the experimental data is lesser for I ≥ 8, particularly for the lighter studied nuclei. (authors)

  12. Beyond RPA in nuclear rotation and wobbling motion at high spin

    International Nuclear Information System (INIS)

    Kaneko, Kazunari

    1991-01-01

    A quantum mechanical method of the nuclear rotation and the wobbling motion at high spin beyond the small-oscillation approximation is represented within the framework of time-dependent mean-field theory with some constraints. The constraints which determine the choice of the rotating reference frame are considered in the spin-orientation frame and the principal-axis frame. The quantization under such constraints is performed by making use of the Dirac bracket. Then the commutation relations of the angular momentum are derived. (orig.)

  13. Unusual Slowly Rotating Brown Dwarfs Discovered through Precision Spitzer Photometry

    Science.gov (United States)

    Heinze, Aren; Metchev, S.

    2014-01-01

    Many brown dwarfs exhibit low-amplitude rotationally modulated variability due to photospheric inhomogeneities caused by condensate clouds in their atmospheres. The Spitzer Space Telescope 'Weather on Other Worlds' (WoW) project has monitored 44 brown dwarfs at unprecedented photometric precision from space. We present one of several important new results from WoW: the discovery of brown dwarfs with unexpectedly slow rotation periods. While most brown dwarfs have periods of 2-12 hours, we have identified two with well-constrained periods of 13±1 and >20 hours, respectively, and 2 others that show more tentative evidence of longer than 20-hour periods. By serving as almost non-rotating standards, these objects will allow more accurate calibration of spectroscopic measurements of brown dwarfs' projected rotational velocities. The existence of such slowly-rotating objects also constrains models of brown dwarf formation and angular momentum evolution.

  14. The interaction of counter-rotating strained vortex pairs with a third vortex

    International Nuclear Information System (INIS)

    Higgins, Keith; Ooi, Andrew; Chong, M S; Ruetten, Markus

    2009-01-01

    The vortex dynamics caused by the interaction of counter-rotating Burgers vortex pairs with a third Burgers vortex in a straining flow is investigated numerically. These interactions blend vortex merging and cancellation effects, and the aim is to investigate how the third vortex might influence the evolution of the vortex pair. Many different choices of initial conditions for the pair and third vortex exist, so attention is restricted to a class of initial conditions in which the vortex pair initially moves in the general direction of vortex 3, and the distance from vortex 3 to the line of free propagation of the vortex pair is the 'offset' parameter δ. A series of calculations with 0≤δ≤4 reveals three types of intermediate-time vortex dynamics that are called merging, swapping and switching. The evolution of the vortex core separation and core vorticity level diagnostics are used to determine the points of transition from merging to swapping and switching. In the longer term, vortex merging, cancellation and straining reduces the three vortices to a single vortex. Other diagnostics of interest are also monitored, including the spatial distributions of the rate of viscous dissipation and terms contributing to the vorticity transport equation. During the merging phase for the case with δ=0, double-peak and double-trough structures are observed in the dissipation-rate contours. In addition, the diffusion of vorticity dominates the vortex-stretching effect near vortex 1 during its absorbtion by vortex 3. Finally, the dynamics of the three vortices are also examined by computing a co-rotating angular velocity and stream function. A series of peaks in the co-rotating angular velocity is found to be associated with the conservation of angular momentum and interactions with a 'ghost' vortex in the co-rotating stream function.

  15. Angular detector of defects in a metallic tube by eddy currents

    International Nuclear Information System (INIS)

    Broudeur, R.

    1990-01-01

    The angular detector of defects in a metallic tube has two centering pieces for the clad positioning on both sides of a backing ring of the measuring coil. The inner diameter of the backing ring and the diameter of the centering pieces are in the ratio 4/3±0.6/3 and their axis are eccentric. This setting over associated at the guiding piece of the sheath in rotation gives at the measuring coil a functioning as a ponctual probe [fr

  16. Identity of the SU(3) model phenomenological hamiltonian and the hamiltonian of nonaxial rotator

    International Nuclear Information System (INIS)

    Filippov, G.F.; Avramenko, V.I.; Sokolov, A.M.

    1984-01-01

    Interpretation of nonspheric atomic nuclei spectra on the basis of phenomenological hamiltonians of SU(3) model showed satisfactory agreement of simulation calculations with experimental data. Meanwhile physical sense of phenomenological hamiltonians was not yet discussed. It is shown that phenomenological hamiltonians of SU(3) model are reduced to hamiltonian of nonaxial rotator but with additional items of the third and fourth powers angular momentum operator of rotator

  17. Coriolis Effects in the Dynamics of a Rotating Elastic Structure

    DEFF Research Database (Denmark)

    Brøns, Morten; Hjorth, Poul G.; Kliem, Wolfhard

    1996-01-01

    Small oscillations of a rotating elasticum with a mass at the free end are investigated with Poincare-Lindstedt series. It is shown that the mass moves on a figure-eight shaped curve in a direction determined by the sign of the angular velocity and hence that the Coriolis force influences...

  18. Quantum control of a chiral molecular motor driven by femtosecond laser pulses: Mechanisms of regular and reverse rotations

    International Nuclear Information System (INIS)

    Yamaki, M.; Hoki, K.; Kono, H.; Fujimura, Y.

    2008-01-01

    Rotational mechanisms of a chiral molecular motor driven by femtosecond laser pulses were investigated on the basis of results of a quantum control simulation. A chiral molecule, (R)-2-methyl-cyclopenta-2,4-dienecarboaldehyde, was treated as a molecular motor within a one-dimensional model. It was assumed that the motor is fixed on a surface and driven in the low temperature limit. Electric fields of femtosecond laser pulses driving both regular rotation of the molecular motor with a plus angular momentum and reverse rotation with a minus one were designed by using a global control method. The mechanism of the regular rotation is similar to that obtained by a conventional pump-dump pulse method: the direction of rotation is the same as that of the initial wave packet propagation on the potential surface of the first singlet (nπ*) excited state S 1 . A new control mechanism has been proposed for the reverse rotation that cannot be driven by a simple pump-dump pulse method. In this mechanism, a coherent Stokes pulse creates a wave packet localized on the ground state potential surface in the right hand side. The wave packet has a negative angular momentum to drive reverse rotation at an early time

  19. Instability of the long head of the biceps tendon in patients with rotator cuff tear: evaluation on magnetic resonance arthrography of the shoulder with arthroscopic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yusuhn; Lee, Joon Woo; Ahn, Joong Mo; Lee, Eugene; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of)

    2017-10-15

    To evaluate the diagnostic value of MR arthrography (MRA) in diagnosing instability of the LHBT in patients with rotator cuff tendon tear. The MR arthrograms of 101 patients were retrospectively reviewed and correlated with arthroscopic findings as the standard reference. Images were evaluated for (1) the integrity of the LHBT, (2) the position of the LHBT (subluxation/dislocation on axial images, inferior displacement on oblique sagittal image) and (3) the integrity of the biceps pulley (SGHL, supraspinatus and subscapularis tendon adjacent to the rotator interval). The integrity of the LHBT was correctly classified in 74.3% (75/101) and 66.3% (67/101) by readers 1 and 2, respectively. The diagnosis of LHBT instability could be made on axial images with a sensitivity of 82.6% and 73.9% and specificity of 69.9% and 87.7%, whereas the displacement sign on sagittal images had a sensitivity of 73.9% and 78.3% and a specificity of 64.4% and 61.6%, respectively. Assessing the integrity of the SGHL had a sensitivity of 60.9 and 93.3% and a specificity of 70.4 and 75.0%, respectively. By combining the different image findings, the accuracy in assessing LHBT instability was 80.9 and 90.5% with a sensitivity of 60.9 and 86.7% and specificity of 83.1 and 91.8%, respectively. Individual image findings may have a limited role in diagnosing LHBT instability in patients with rotator cuff tendon tear. The accuracy of MRA may be improved by assessing the integrity of the biceps pulley structures along with the position of the LHBT on both axial and sagittal images. (orig.)

  20. Reliability of the xipho-pubic angle in patients with sagittal imbalance of the spine.

    Science.gov (United States)

    Langella, Francesco; Villafañe, Jorge H; Ismael, Maryem; Buric, Josip; Piazzola, Andrea; Lamartina, Claudio; Berjano, Pedro

    2018-04-01

    Proximal junctional kyphosis (PJK) is a frequent complication that compromises the outcomes of spinal surgery, especially for adult deformity. To the date no single risk factor or cause has been identified that explains its occurrence. The purpose of this study was to investigate the test-retest reliability of the radiologic measurements using xipho-pubic angle (XPA) for subjects undergoing surgery for sagittal misalignment of the spine. Retrospective observational cross-sectional study of prospectively collected data. Full-spine standing lateral radiographs of 50 patients who underwent surgery for fixed sagittal imbalance (preoperative and postoperative) were evaluated. Internal consistency, reproducibility, concurrent validity, and discriminative ability of the XPA. Two physicians measured XPA on the 100 randomly sorted and anonymized radiographs on two occasions, one week apart (test and retest conditions), were calculated for inter and intraobserver agreement. Test-retest reliability of XPA measurement was excellent for pre- (ICC=0.98; P=0.001) and post-surgical (ICC=0.86; P=0.001) radiographs of subjects with sagittal imbalance of the spine. XPA was able to discriminate between preoperative and postoperative radiographs F=17.924, Pimbalance for both raters. There were significant differences between pre- vs. postoperative XPA, pelvic tilt, lumbar lordosis and sagittal vertical axis values (all Pimbalance.

  1. Relationship between thoracic hypokyphosis, lumbar lordosis and sagittal pelvic parameters in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Clément, Jean-Luc; Geoffray, Anne; Yagoubi, Fatima; Chau, Edouard; Solla, Federico; Oborocianu, Ioana; Rampal, Virginie

    2013-11-01

    Sagittal spine and pelvic alignment of adolescent idiopathic scoliosis (AIS) is poorly described in the literature. It generally reports the sagittal alignment with regard to the type of curve and never correlated to the thoracic kyphosis. The objective of this study is to investigate the relationship between thoracic kyphosis, lumbar lordosis and sagittal pelvic parameters in thoracic AIS. Spinal and pelvic sagittal parameters were evaluated on lateral radiographs of 86 patients with thoracic AIS; patients were separated into hypokyphosis group (n = 42) and normokyphosis group (n = 44). Results were statistically analyzed. The lumbar lordosis was lower in the hypokyphosis group, due to the low proximal lordosis. The thoracic kyphosis was not correlated with any pelvic parameters but with the proximal lordosis. The pelvic incidence was correlated with sacral slope, pelvic tilt, lumbar lordosis and highly correlated with distal lumbar lordosis in the two groups. There was a significant linear regression between thoracic kyphosis and proximal lordosis and between pelvic incidence and distal lordosis. We can consider that the proximal part of the lordosis depends on the thoracic kyphosis and the distal part depends on the pelvic incidence. The hypokyphosis in AIS is independent of the pelvic parameters and could be described as a structural parameter, characteristic of the scoliotic deformity.

  2. Magnetorotational Instability in a Rotating Liquid Metal Annulus

    International Nuclear Information System (INIS)

    Hantao Ji; Jeremy Goodman; Akira Kageyama

    2001-01-01

    Although the magnetorotational instability (MRI) has been widely accepted as a powerful accretion mechanism in magnetized accretion disks, it has not been realized in the laboratory. The possibility of studying MRI in a rotating liquid-metal annulus (Couette flow) is explored by local and global stability analysis and magnetohydrodynamic (MHD) simulations. Stability diagrams are drawn in dimensionless parameters, and also in terms of the angular velocities at the inner and outer cylinders. It is shown that MRI can be triggered in a moderately rapidly rotating table-top apparatus, using easy-to-handle metals such as gallium. Practical issues of this proposed experiment are discussed

  3. Magnetic resonance imaging findings associated with surgically proven rotator interval lesions

    Energy Technology Data Exchange (ETDEWEB)

    Vinson, Emily N.; Major, Nancy M. [Duke University Medical Center, Department of Radiology, P.O. Box 3808, Durham, NC (United States); Higgins, Laurence D. [Brigham and Women' s Hospital, Department of Orthopedic Surgery, Boston, MA (United States)

    2007-05-15

    To identify shoulder magnetic resonance imaging (MRI) findings associated with surgically proven rotator interval abnormalities. The preoperative MRI examinations of five patients with surgically proven rotator interval (RI) lesions requiring closure were retrospectively evaluated by three musculoskeletal-trained radiologists in consensus. We assessed the structures in the RI, including the coracohumeral ligament, superior glenohumeral ligament, fat tissue, biceps tendon, and capsule for variations in size and signal alteration. In addition, we noted associated findings of rotator cuff and labral pathology. Three of three of the MR arthrogram studies demonstrated extension of gadolinium to the cortex of the undersurface of the coracoid process compared with the control images, seen best on the sagittal oblique images. Four of five of the studies demonstrated subjective thickening of the coracohumeral ligament, and three of five of the studies demonstrated subjective thickening of the superior glenohumeral ligament. Five of five of the studies demonstrated a labral tear. The MRI arthrogram finding of gadolinium extending to the cortex of the undersurface of the coracoid process was noted on the studies of those patients with rotator interval lesions at surgery in this series. Noting this finding - especially in the presence of a labral tear and/or thickening of the coracohumeral ligament or superior glenohumeral ligament - may be helpful in the preoperative diagnosis of rotator interval lesions. (orig.)

  4. One-electron densities of freely rotating Wigner molecules

    Science.gov (United States)

    Cioslowski, Jerzy

    2017-12-01

    A formalism enabling computation of the one-particle density of a freely rotating assembly of identical particles that vibrate about their equilibrium positions with amplitudes much smaller than their average distances is presented. It produces densities as finite sums of products of angular and radial functions, the length of the expansion being determined by the interplay between the point-group and permutational symmetries of the system in question. Obtaining from a convolution of the rotational and bosonic components of the parent wavefunction, the angular functions are state-dependent. On the other hand, the radial functions are Gaussians with maxima located at the equilibrium lengths of the position vectors of individual particles and exponents depending on the scalar products of these vectors and the eigenvectors of the corresponding Hessian as well as the respective eigenvalues. Although the new formalism is particularly useful for studies of the Wigner molecules formed by electrons subject to weak confining potentials, it is readily adaptable to species (such as ´balliums’ and Coulomb crystals) composed of identical particles with arbitrary spin statistics and permutational symmetry. Several examples of applications of the present approach to the harmonium atoms within the strong-correlation regime are given.

  5. Study of high angular momentum phenomena in rotating nuclei

    International Nuclear Information System (INIS)

    Walus, W.

    1982-01-01

    Information about rotational bands of deformed Yb nuclei as obtained through in-beam spectroscopic studies is discussed. Routhians and alignments have been extracted from the experimental data. Experimental single-quasineutron routhians have been used to construct two- and three-quasineutron routhians. Residual interaction between excited quasiparticles is obtained from a comparison of the excitation energies of multiple-quasiparticle states constructed from single-quasiparticle states. An odd-even neutron-number dependence of the alignment frequency of the first pair of isub(13/2) quasineutron in rare-earth nuclei is presented. This effect is explained by a reduction of the neutron pairing-correlation parameter for odd-N systems as compared to seniority-zero configurations in even-N nuclei. The signature dependence of the interband-intraband branching ratios as well as of the interband M1/E2 mixing ratios is discussed and compared to the signature dependence of B(M1) transition rates recently suggested by Hamamoto. (author)

  6. Extensor Tendon Instability Due to Sagittal Band Injury in a Martial Arts Athlete: A Case Report.

    Science.gov (United States)

    Kochevar, Andrew; Rayan, Ghazi

    2017-03-01

    A Taekwondo participant sustained a hand injury from punching an opponent that resulted in painful instability of the ring finger extensor digitorum communis tendon due to sagittal band damage. His symptoms resolved after reconstructive surgery on the sagittal band (SB) with stabilization of the extensor tendon over the metacarpophalangeal joint.

  7. Stunted accretion growth of black holes by combined effect of the flow angular momentum and radiation feedback

    Science.gov (United States)

    Sugimura, Kazuyuki; Hosokawa, Takashi; Yajima, Hidenobu; Inayoshi, Kohei; Omukai, Kazuyuki

    2018-05-01

    Accretion on to seed black holes (BHs) is believed to play a crucial role in formation of supermassive BHs observed at high-redshift (z > 6). Here, we investigate the combined effect of gas angular momentum and radiation feedback on the accretion flow, by performing 2D axially symmetric radiation hydrodynamics simulations that solve the flow structure across the Bondi radius and the outer part of the accretion disc simultaneously. The accreting gas with finite angular momentum forms a rotationally-supported disc inside the Bondi radius, where the accretion proceeds by the angular momentum transport due to assumed α-type viscosity. We find that the interplay of radiation and angular momentum significantly suppresses accretion even if the radiative feedback is weakened in an equatorial shadowing region. The accretion rate is O(α) ˜ O(0.01 - 0.1) times the Bondi value, where α is the viscosity parameter. By developing an analytical model, we show that such a great reduction of the accretion rate persists unless the angular momentum is so small that the corresponding centrifugal radius is ≲ 0.04 times the Bondi radius. We argue that BHs are hard to grow quickly via rapid mass accretion considering the angular momentum barrier presented in this paper.

  8. Effect of lordosis angle change after lumbar/lumbosacral fusion on sacrum angular displacement: a finite element study.

    Science.gov (United States)

    Mao, Ningfang; Shi, Jian; He, Dawei; Xie, Yang; Bai, Yushu; Wei, Xianzhao; Shi, Zhicai; Li, Ming

    2014-11-01

    To assess and characterize the sacrum angular displacements in response to lumbar lordosis after lumbar/lumbosacral fusion. A finite element model of the lower lumbar spine-pelvis was established and used to simulate the posterior fusion at L3-L5 and L4-S1. The lordosis angle in the fusion segments was set to five different conditions with respect to the intact model: 10° less than intact, 5° less than intact, same as intact, 5° more than intact, and 10° more than intact. Variations of the sacrum angular displacements with lordosis changes were analyzed under loading setting of axial compression, flexion, extension, lateral bending, and axial rotation. Compared with the intact lordosis, both increased and decreased lumbar lordosis angles caused the sacrum angular displacements to be increased. The lordosis angle increased by 10° induced the most substantial increase in sacrum angular displacements. In addition, the sacrum angular displacements of the L4-S1 fusion model at different lordosis angles were higher than those of the L3-L5 fusion model. The sacrum angular displacements occur as a result of the fusion surgery (L4-S1) and the changes in lumbar lordosis.

  9. Rotational Angles and Velocities During Down the Line and Diagonal Across Court Volleyball Spikes

    Directory of Open Access Journals (Sweden)

    Justin R. Brown

    2014-05-01

    Full Text Available The volleyball spike is an explosive movement that is frequently used to end a rally and earn a point. High velocity spikes are an important skill for a successful volleyball offense. Although the influence of vertical jump height and arm velocity on spiked ball velocity (SBV have been investigated, little is known about the relationship of shoulder and hip angular kinematics with SBV. Other sport skills, like the baseball pitch share similar movement patterns and suggest trunk rotation is important for such movements. The purpose of this study was to examine the relationship of both shoulder and hip angular kinematics with ball velocity during the volleyball spike. Methods: Fourteen Division I collegiate female volleyball players executed down the line (DL and diagonally across-court (DAC spikes in a laboratory setting to measure shoulder and hip angular kinematics and velocities. Each spike was analyzed using a 10 Camera Raptor-E Digital Real Time Camera System.  Results: DL SBV was significantly greater than for DAC, respectively (17.54±2.35 vs. 15.97±2.36 m/s, p<0.05.  The Shoulder Hip Separation Angle (S-HSA, Shoulder Angular Velocity (SAV, and Hip Angular Velocity (HAV were all significantly correlated with DAC SBV. S-HSA was the most significant predictor of DAC SBV as determined by regression analysis.  Conclusions: This study provides support for a relationship between a greater S-HSA and SBV. Future research should continue to 1 examine the influence of core training exercise and rotational skill drills on SBV and 2 examine trunk angular velocities during various types of spikes during play.

  10. Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

    International Nuclear Information System (INIS)

    Oudih, M.R.; Benhamouda, N.; Fellah, M.; Allal, N.H.

    2000-01-01

    A method of simultaneous particle-number and angular-momentum projection of the BCS wave-function is presented. The particle number projection method is of FBCS type. In the frame work of the adiabatic approximation, the rotational energies of the axially symmetric even-even nuclei are established and numerically calculated for the rare-earth region. (author)

  11. Rotator cuff pathology

    International Nuclear Information System (INIS)

    Pigeau, I.; Doursounian, L.; Maigne, J.Y.; Guinet, C.; Meary, E.; Buy, J.N.; Touzard, R.C.; Vadrot, D.; Laval-Jeantet, M.

    1989-01-01

    Fifteen volunteers and 73 patients with suspected rotator cuff lesions were examined at 0.5 T with T2 * -weighted gradient-echo (GE) MR imaging (700/33/30 degrees) (oblique coronal and sagittal 3 mm thick, surface coil). Results were compared with those of arthrography (all cases), T1-weighted GE imaging (400/20/90 degrees) (35 cases), surgery (28 cases), and T2-weighted spin-echo (SE) images (2,000/60-120) (17 cases). GE images demonstrated all tears (complete, 32, partial, 12) and was superior to arthrography in determining site and size and in displaying muscles (critical point in surgical planning). In 20 cases without tears on arthrography, GE imaging demonstrated five cases of tendinitis, five cases of bursitis, and six probable intratendinous or superficial partial tears. T2 * -weighted GE imaging was superior to T2-weighted SE and T1-weighted GE imaging, with higher fluid contrast and a low fat signal. Therefore, it might replace arthrography in the diagnosis and surgical approach to this pathology

  12. Angular velocity and centripetal acceleration relationship

    Science.gov (United States)

    Monteiro, Martín; Cabeza, Cecilia; Marti, Arturo C.; Vogt, Patrik; Kuhn, Jochen

    2014-05-01

    During the last few years, the growing boom of smartphones has given rise to a considerable number of applications exploiting the functionality of the sensors incorporated in these devices. A sector that has unexpectedly taken advantage of the power of these tools is physics teaching, as reflected in several recent papers. In effect, the use of smartphones has been proposed in several physics experiments spanning mechanics, electromagnetism, optics, oscillations, and waves, among other subjects. Although mechanical experiments have received considerable attention, most of them are based on the use of the accelerometer. An aspect that has received less attention is the use of rotation sensors or gyroscopes. An additional advance in the use of these devices is given by the possibility of obtaining data using the accelerometer and the gyroscope simultaneously. The aim of this paper is to consider the relation between the centripetal acceleration and the angular velocity. Instead of using a formal laboratory setup, in this experiment a smartphone is attached to the floor of a merry-go-round, found in many playgrounds. Several experiments were performed with the roundabout rotating in both directions and with the smart-phone at different distances from the center. The coherence of the measurements is shown.

  13. Anterior sagittal transanorectal approach to the posterior urethra in the pediatric age group.

    Science.gov (United States)

    Rossi, F; De Castro, R; Ceccarelli, P L; Dòmini, R

    1998-09-01

    Surgical access to the posterior urethra is often difficult and several surgical solutions have been proposed. We suggest an anterior sagittal transanorectal approach based on splitting the anterior rectal wall only. This alternative technique provides excellent exposure to the retrourethral region, permitting simple and safe surgery. Between 1994 and 1996 we performed surgery via the anterior sagittal transanorectal approach in 8 patients with a mean age of 9.06 years. Patients included 1 girl with a posttraumatic urethrovaginal fistula, 3 with intersex disorders (2 with mixed gonadal dysgenesis raised as boys and 1 with male dysgenetic pseudohermaphroditism with an enlarged urtricle) and 4 boys (1 with penile agenesis raised as girl, 2 with urethral duplication and 1 with prostatic rhabdomyosarcoma). The patient was placed in a knee-chest position. A midline sagittal incision was made through the anterior anorectal wall only and deepened through the perineal body to expose the posterior urethra and retrovesical space. After the pathological condition was corrected the anterior rectal wall and perineal body were reconstructed. The operation was completed with protective colostomy. In our final patient with prostatic rhabdomyosarcoma the anterior sagittal transanorectal approach was used without colostomy. Anorectal manometry was done 6 months postoperatively. All patients were completely continent of stool and urine. Convalescence was unremarkable in all cases. Postoperative manometry in 7 patients revealed no differences from preoperative measurements. This procedure should be considered a useful alternative to other techniques for various congenital and acquired pelvic disorders.

  14. Elliptical Galaxies: Rotationally Distorted, After All

    Directory of Open Access Journals (Sweden)

    Caimmi, R.

    2009-12-01

    Full Text Available On the basis of earlier investigations onhomeoidally striated Mac Laurin spheroids and Jacobi ellipsoids (Caimmi and Marmo2005, Caimmi 2006a, 2007, different sequences of configurations are defined and represented in the ellipticity-rotation plane, $({sf O}hat{e}chi_v^2$. The rotation parameter, $chi_v^2$, is defined as the ratio, $E_mathrm{rot}/E_mathrm{res}$, of kinetic energy related to the mean tangential equatorial velocity component, $M(overline{v_phi}^2/2$, to kineticenergy related to tangential equatorial component velocity dispersion, $Msigma_{phiphi}^2/2$, andresidual motions, $M(sigma_{ww}^2+sigma_{33}^2/2$.Without loss of generality (above a thresholdin ellipticity values, the analysis is restricted to systems with isotropic stress tensor, whichmay be considered as adjoint configurationsto any assigned homeoidally striated density profile with anisotropic stress tensor, different angular momentum, and equal remaining parameters.The description of configurations in the$({sf O}hat{e}chi_v^2$ plane is extendedin two respects, namely (a from equilibriumto nonequilibrium figures, where the virialequations hold with additional kinetic energy,and (b from real to imaginary rotation, wherethe effect is elongating instead of flattening,with respect to the rotation axis.An application is made toa subsample $(N=16$ of elliptical galaxies extracted from richer samples $(N=25,~N=48$of early type galaxies investigated within theSAURON project (Cappellari et al. 2006, 2007.Sample objects are idealized as homeoidallystriated MacLaurinspheroids and Jacobi ellipsoids, and theirposition in the $({sf O}hat{e}chi_v^2$plane is inferred from observations followinga procedure outlined in an earlier paper(Caimmi 2009b. The position of related adjoint configurations with isotropic stresstensor is also determined. With a singleexception (NGC 3379, slow rotators arecharacterized by low ellipticities $(0lehat{e}<0.2$, low anisotropy parameters$(0ledelta<0

  15. Impact of sagittal spinopelvic alignment on clinical outcomes after decompression surgery for lumbar spinal canal stenosis without coronal imbalance.

    Science.gov (United States)

    Hikata, Tomohiro; Watanabe, Kota; Fujita, Nobuyuki; Iwanami, Akio; Hosogane, Naobumi; Ishii, Ken; Nakamura, Masaya; Toyama, Yoshiaki; Matsumoto, Morio

    2015-10-01

    The object of this study was to investigate correlations between sagittal spinopelvic alignment and improvements in clinical and quality-of-life (QOL) outcomes after lumbar decompression surgery for lumbar spinal canal stenosis (LCS) without coronal imbalance. The authors retrospectively reviewed data from consecutive patients treated for LCS with decompression surgery in the period from 2009 through 2011. They examined correlations between preoperative or postoperative sagittal vertical axis (SVA) and radiological parameters, clinical outcomes, and health-related (HR)QOL scores in patients divided according to SVA. Clinical outcomes were assessed according to Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores. Health-related QOL was evaluated using the Roland-Morris Disability Questionnaire (RMDQ) and the JOA Back Pain Evaluation Questionnaire (JOABPEQ). One hundred nine patients were eligible for inclusion in the study. Compared to patients with normal sagittal alignment prior to surgery (Group A: SVA imbalance (Group B: SVA ≥ 50 mm) had significantly smaller lumbar lordosis and thoracic kyphosis angles and larger pelvic tilt. In Group B, there was a significant decrease in postoperative SVA compared with the preoperative SVA (76.3 ± 29.7 mm vs. 54.3 ± 39.8 mm, p = 0.004). The patients in Group B with severe preoperative sagittal imbalance (SVA > 80 mm) had residual sagittal imbalance after surgery (82.8 ± 41.6 mm). There were no significant differences in clinical and HRQOL outcomes between Groups A and B. Compared to patients with normal postoperative SVA (Group C: SVA imbalance. Decompression surgery improved the SVA value in patients with preoperative sagittal imbalance; however, the patients with severe preoperative sagittal imbalance (SVA > 80 mm) had residual imbalance after decompression surgery. Both clinical and HRQOL outcomes were negatively affected by postoperative residual sagittal imbalance.

  16. On the coherent rotation of diffuse matter in numerical simulations of clusters of galaxies

    Science.gov (United States)

    Baldi, Anna Silvia; De Petris, Marco; Sembolini, Federico; Yepes, Gustavo; Lamagna, Luca; Rasia, Elena

    2017-03-01

    We present a study on the coherent rotation of the intracluster medium and dark matter components of simulated galaxy clusters extracted from a volume-limited sample of the MUSIC project. The set is re-simulated with three different recipes for the gas physics: (I) non-radiative, (II) radiative without active galactic nuclei (AGN) feedback and (III) radiative with AGN feedback. Our analysis is based on the 146 most massive clusters identified as relaxed, 57 per cent of the total sample. We classify these objects as rotating and non-rotating according to the gas spin parameter, a quantity that can be related to cluster observations. We find that 4 per cent of the relaxed sample is rotating according to our criterion. By looking at the radial profiles of their specific angular momentum vector, we find that the solid body model is not a suitable description of rotational motions. The radial profiles of the velocity of the dark matter show a prevalence of the random velocity dispersion. Instead, the intracluster medium profiles are characterized by a comparable contribution from the tangential velocity and the dispersion. In general, the dark matter component dominates the dynamics of the clusters, as suggested by the correlation between its angular momentum and the gas one, and by the lack of relevant differences among the three sets of simulations.

  17. Alphabet Soup: Sagittal Balance Correction Osteotomies of the Spine-What Radiologists Should Know.

    Science.gov (United States)

    Takahashi, T; Kainth, D; Marette, S; Polly, D

    2018-04-01

    Global sagittal malalignment has been demonstrated to have correlation with clinical symptoms and is a key component to be restored in adult spinal deformity. In this article, various types of sagittal balance-correction osteotomies are reviewed primarily on the basis of the 3 most commonly used procedures: Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection. Familiarity with the expected imaging appearance and commonly encountered complications seen on postoperative imaging studies following correction osteotomies is crucial for accurate image interpretation. © 2018 by American Journal of Neuroradiology.

  18. Internal differential rotation of the Sun: the P-modes frequency splitting in the measurements of brightness oscillations

    International Nuclear Information System (INIS)

    Didkovskij, L.V.

    1989-01-01

    a 12-DAY SERIES OF TWO-DIMNIONAL IMAGES OF SOLAR BRIGHTNESS OSCILLATIONS EIGENFREQUENCIES in the range of 6-32 degrees. The rotational frequency splitting of separate modes as a function of inner turn-points radius of acoustic waves is found. The results of the analysis shw fast rotation of the central region of the Sun and non-monotonous trend of angular rotation velocity varitions with radius of the boundary of solar core

  19. The error model and experiment of measuring angular position error based on laser collimation

    Science.gov (United States)

    Cai, Yangyang; Yang, Jing; Li, Jiakun; Feng, Qibo

    2018-01-01

    Rotary axis is the reference component of rotation motion. Angular position error is the most critical factor which impair the machining precision among the six degree-of-freedom (DOF) geometric errors of rotary axis. In this paper, the measuring method of angular position error of rotary axis based on laser collimation is thoroughly researched, the error model is established and 360 ° full range measurement is realized by using the high precision servo turntable. The change of space attitude of each moving part is described accurately by the 3×3 transformation matrices and the influences of various factors on the measurement results is analyzed in detail. Experiments results show that the measurement method can achieve high measurement accuracy and large measurement range.

  20. Untangling Galaxy Components - The Angular Momentum Parameter

    Science.gov (United States)

    Tabor, Martha; Merrifield, Michael; Aragon-Salamanca, Alfonso

    2017-06-01

    We have developed a new technique to decompose Integral Field spectral data cubes into separate bulge and disk components, allowing us to study the kinematic and stellar population properties of the individual components and how they vary with position. We present here the application of this method to a sample of fast rotator early type galaxies from the MaNGA integral field survey, and demonstrate how it can be used to explore key properties of the individual components. By extracting ages, metallicities and the angular momentum parameter lambda of the bulges and disks, we show how this method can give us new insights into the underlying structure of the galaxies and discuss what this can tell us about their evolution history.

  1. Magnetic interaction of positronium atoms measured by perturbed angular distribution in 3 gamma annihilation decay

    International Nuclear Information System (INIS)

    Ivanov, E.; Vata, I.; Plostinaru, D.; Catana, D.; Dudu, D.; Constantinescu, O.

    2003-01-01

    The Time Differential Perturbed Angular Distribution (TDPAD) method in connection with long-lived Positron Life-Time Spectroscopy (PLTS) have been used to observe 'quantum beat' spin oscillations of positronium atom in an external magnetic field. Our results offer an encouraging hint toward a new method of condensed matter investigation by PLTS. Similarities with Muonium Spin Rotation (μSR) method are suggested. (authors)

  2. Evaluation of uterine peristalsis using cine MRI on the coronal plane in comparison with the sagittal plane.

    Science.gov (United States)

    Shitano, Fuki; Kido, Aki; Kataoka, Masako; Fujimoto, Koji; Kiguchi, Kayo; Fushimi, Yasutaka; Togashi, Kaori

    2016-01-01

    Uterine peristalsis is supposed to be closely related to the early stages of reproduction. Sperms are preferentially transported from the uterine cervix to the side of the tube with the dominant follicle. However, with respect to magnetic resonance imaging (MRI), uterine peristalsis has only been evaluated at the sagittal plane of cine MRI. To evaluate and compare uterine peristalsis both on sagittal and coronal planes using cine MRI. Internal ethics committee approval was obtained, and subjects provided informed written consent. Thirty-one women underwent MRI scans in the periovulatory phase of the menstrual cycle. Cine MR images obtained by fast advanced spin echo sequence at 3-T field strength magnet (Toshiba Medical Systems) were visually evaluated by two independent radiologists. The frequency and the direction of peristalsis, and the presence of outer myometrium conduction of signal intensities (OMC), were evaluated. The laterality of the dominant follicle was determined on axial images and compared with the peristaltic direction in fundus. The subjects in which peristaltic directions were more clearly recognized were significantly frequent in coronal planes than in sagittal planes (P < 0.05). There was no significant difference in the peristaltic frequency between the sagittal and the coronal plane. However, the OMC was more recognized in the coronal plane than in the sagittal plane (P < 0.05). Peristaltic waves conducted toward the possible ovulation side were observed in only three of the 10 subjects. OMC of uterine peristalsis was better demonstrated in the coronal plane compared to the sagittal plane. © The Foundation Acta Radiologica 2015.

  3. Gender difference of ankle stability in the sagittal and frontal planes.

    Science.gov (United States)

    Hanzlick, Harrison; Hyunglae Lee

    2017-07-01

    This paper offers quantification of ankle stability in relation to simulated haptic environments of varying stiffness. This study analyzes the stability trends of male and female subjects independently over a wide range of simulated environments after subjects were exposed to vigorous position perturbation. Ankle stability was quantified for both degrees-of-freedom of the ankle in the sagittal and frontal planes. Subjects' stability consistently decreased when exposed to environments of negative simulated stiffness. In the frontal plane, male and female subjects exhibited nearly identical stability levels. In the sagittal plane, however, male subjects demonstrated marginally more stability than female subjects in environments with negative stiffness. Results of this study are beneficial to understanding situations in which the ankle is likely to lose stability, potentially resulting in injury.

  4. Giant resonances in hot rotating nuclei

    International Nuclear Information System (INIS)

    Ring, P.

    1992-01-01

    Present theoretical descriptions of the giant resonances in hot rotating nuclei are reviewed. Mean field theory is used as a basis for the description of the hot compound states. Starting from the static solution at finite temperature and with fixed angular momentum small amplitude collective vibrations are calculated in the frame work of finite temperature random phase approximation for quasi-particles. The effect of pairing at low temperatures as well as the effect of rotations on the position of the resonance maxima are investigated. Microscopic and phenomenological descriptions of the damping mechanisms are reviewed. In particular it turns out that fluctuations play an important role in understanding of the behaviour of the width as a function of the temperature. Motional narrowing is critically discussed. (author). 99 refs., 5 figs

  5. Main effects of the Earth's rotation on the stationary states of ultra-cold neutrons

    International Nuclear Information System (INIS)

    Arminjon, Mayeul

    2008-01-01

    The relativistic corrections in the Hamiltonian for a particle in a uniformly rotating frame are discussed. They are shown to be negligible in the case of ultra-cold neutrons (UCN) in the Earth's gravity. The effect, on the energy levels of UCN, of the main term due to the Earth's rotation, i.e. the angular-momentum term, is calculated. The energy shift is found proportional to the energy level itself

  6. Bulk Decay of (4 + n)-Dimensional Simply Rotating Black Holes: Tensor-Type Gravitons

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, Nikolaos, E-mail: npappas@cc.uoi.gr [Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110 (Greece)

    2011-02-01

    We study the emission in the bulk of tensor-type gravitons by a simply rotating (4 + n)-dimensional black hole. The decoupling of the radial and angular part of the graviton field equation makes it possible to solve them analytically (in the limit of low-energy emitted particles and low-angular momentum of the black hole) and find the corresponding absorption probability. We also move to solve these equations numerically. The comparison between analytic and numerical results shows a very good agreement in low and intermediate energy regimes. Finally, the energy and angular momentum emission rates were calculated in order to explore their dependence on the number of additional spacelike dimensions of the spacetime background and the angular momentum of the black hole. Interesting conclusions about the significance of tensor-type gravitons as energy carriers in the context of Hawking radiation were reached.

  7. Bulk Decay of (4 + n)-Dimensional Simply Rotating Black Holes: Tensor-Type Gravitons

    International Nuclear Information System (INIS)

    Pappas, Nikolaos

    2011-01-01

    We study the emission in the bulk of tensor-type gravitons by a simply rotating (4 + n)-dimensional black hole. The decoupling of the radial and angular part of the graviton field equation makes it possible to solve them analytically (in the limit of low-energy emitted particles and low-angular momentum of the black hole) and find the corresponding absorption probability. We also move to solve these equations numerically. The comparison between analytic and numerical results shows a very good agreement in low and intermediate energy regimes. Finally, the energy and angular momentum emission rates were calculated in order to explore their dependence on the number of additional spacelike dimensions of the spacetime background and the angular momentum of the black hole. Interesting conclusions about the significance of tensor-type gravitons as energy carriers in the context of Hawking radiation were reached.

  8. The role of cranking frequency in the generation of angular momentum in isospin formalism for nuclei around A=90

    International Nuclear Information System (INIS)

    Mohamed Akbar, A.; Veeraraghavan, S.; Arunachalam, N.

    1998-01-01

    The role of cranking frequency in hot rotating deformed nuclei has been studied with reference to the extraction of several nuclear parameters. In this work, the angular momentum degree of freedom is included in the isospin formalism using statistical theory of hot deformed nuclei

  9. Behavior of a test gyroscope moving towards a rotating traversable wormhole

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Chandrachur [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005 India (India); Pradhan, Parthapratim, E-mail: chandrachur.chakraborty@tifr.res.in, E-mail: pppradhan77@gmail.com [Department of Physics, Vivekananda Satabarshiki Mahavidyalaya, Manikpara, West Midnapur, 721513 India (India)

    2017-03-01

    The geodesic structure of the Teo wormhole is briefly discussed and some observables are derived that promise to be of use in detecting a rotating traversable wormhole indirectly, if it does exist. We also deduce the exact Lense-Thirring (LT) precession frequency of a test gyroscope moving toward a rotating traversable Teo wormhole. The precession frequency diverges on the ergoregion, a behavior intimately related to and governed by the geometry of the ergoregion, analogous to the situation in a Kerr spacetime. Interestingly, it turns out that here the LT precession is inversely proportional to the angular momentum ( a ) of the wormhole along the pole and around it in the strong gravity regime, a behavior contrasting with its direct variation with a in the case of other compact objects. In fact, divergence of LT precession inside the ergoregion can also be avoided if the gyro moves with a non-zero angular velocity in a certain range. As a result, the spin precession frequency of the gyro can be made finite throughout its whole path, even very close to the throat, during its travel to the wormhole. Furthermore, it is evident from our formulation that this spin precession not only arises due to curvature or rotation of the spacetime but also due to the non-zero angular velocity of the spin when it does not move along a geodesic in the strong gravity regime. If in the future, interstellar travel indeed becomes possible through a wormhole or at least in its vicinity, our results would prove useful in determining the behavior of a test gyroscope which is known to serve as a fundamental navigation device.

  10. Development of Rotational Accelerometers Final Report CRADA No. TSB-2008-99

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Crosson, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    One of the difficulties in fabricating an inexpensive angular rate or rotation sensor is producing a device that is insensitive to acceleration, including the constant acceleration of gravity. The majority of rate sensors are either tuning fork type devices sensing a relatively weak force (i.e., Coriolis effect) and thus not very sensitive, or gyroscopes (either rotating or fiber optic based) that are large, consume lots of power and are expensive. This project was a collaborative effort between LLNL and The Fredericks Company to develop a rotational sensor as a standardized, commercial product. The Fredericks Company possessed expertise and capabilities in the technical aspects of manufacturing this type of sensor, and they were interested in collaborating with LLNL to manufacture the rotational rate sensors as a commercial product.

  11. Lock-in amplifier- based rotating- analyzer spectroscopic ellipsometer with micro-controlled angular frequency

    Energy Technology Data Exchange (ETDEWEB)

    Flores C, J.M.; Nunez O, O.F.; Rodriguez P, G.; Lastras M, A.; Lastras M, L.F. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi (Mexico)

    2005-07-01

    We report on the development of a full operational rotating analyzer spectroscopic ellipsometer. This instrument employs a phase-sensitive amplifier to process the optical signal as an alternative to Fast Fourier Transform analysis. We describe electronic hardware designed to stabilize the rotation frequency of the analyzer prism as well as to drive the device for the positioning of the polarizer prism azimuth. The ellipsometer allows for dielectric function measurement in the energy range from 1.7-5.5 eV, in both ambient air and Ultra High Vacuum (UHV). UHV measurements can be carried out at a temperature as low as 150 K. To evaluate the ellipsometer performance we present results of the determination of the complex dielectric function of a number of semiconductors, namely, GaSb, GaAs, InGaAs, CdTe and CdHgTe. (Author)

  12. Gravitational collapse with rotating thin shells and cosmic censorship

    International Nuclear Information System (INIS)

    Delsate, Térence; Rocha, Jorge V; Santarelli, Raphael

    2015-01-01

    The study of gravitational collapse is a subject of great importance, both from an astrophysical and a holographic point of view. In this respect, exact solutions can be very helpful but known solutions are very scarce, especially when considering dynamical processes with rotation. We describe a setup in which gravitational collapse of rotating matter shells can be addressed with analytic tools, at the expense of going to higher dimensions and considering equal angular momenta spacetimes. The framework for an exact treatment of the dynamics, relying on a thin shell approximation, is developed. Our analysis allows the inclusion of a non-vanishing cosmological constant. Finally, we discuss applications of this machinery to the construction of stationary solutions describing matter around rotating black holes and to the cosmic censorship conjecture. (paper)

  13. Improper trunk rotation sequence is associated with increased maximal shoulder external rotation angle and shoulder joint force in high school baseball pitchers.

    Science.gov (United States)

    Oyama, Sakiko; Yu, Bing; Blackburn, J Troy; Padua, Darin A; Li, Li; Myers, Joseph B

    2014-09-01

    In a properly coordinated throwing motion, peak pelvic rotation velocity is reached before peak upper torso rotation velocity, so that angular momentum can be transferred effectively from the proximal (pelvis) to distal (upper torso) segment. However, the effects of trunk rotation sequence on pitching biomechanics and performance have not been investigated. The aim of this study was to investigate the effects of trunk rotation sequence on ball speed and on upper extremity biomechanics that are linked to injuries in high school baseball pitchers. The hypothesis was that pitchers with improper trunk rotation sequence would demonstrate lower ball velocity and greater stress to the joint. Descriptive laboratory study. Three-dimensional pitching kinematics data were captured from 72 high school pitchers. Subjects were considered to have proper or improper trunk rotation sequences when the peak pelvic rotation velocity was reached either before or after the peak upper torso rotation velocity beyond the margin of error (±3.7% of the time from stride-foot contact to ball release). Maximal shoulder external rotation angle, elbow extension angle at ball release, peak shoulder proximal force, shoulder internal rotation moment, and elbow varus moment were compared between groups using independent t tests (α ways that may influence injury risk. As such, exercises that reinforce the use of a proper trunk rotation sequence during the pitching motion may reduce the stress placed on the structures around the shoulder joint and lead to the prevention of injuries. © 2014 The Author(s).

  14. Theoretical Investigation of Creeping Viscoelastic Flow Transition Around a Rotating Curved Pipe

    OpenAIRE

    Hamza, S. E. E.; El-Bakry, Mostafa Y.

    2015-01-01

    The study of creeping motion of viscoelastic fluid around a rotating rigid torus is investigated. The analysis of the problem is performed using a second-order viscoelastic model. The study is carried out in terms of the bipolar toroidal system of coordinates where the toroid is rotating about its axis of symmetry (z-axis). The problem is solved within the frame of slow flow approximation. Therefore, all variables in the governing equations are expanded in a power series of angular velocity. ...

  15. The giant quadrupole resonance in highly excited rotating nuclei

    International Nuclear Information System (INIS)

    Civitarese, O.; Furui, S.; Ploszajczak, M.; Faessler, A.

    1983-01-01

    The giant quadrupole resonance in highly excited, fast rotating nuclei is studied as a function of both the nuclear temperature and the nuclear angular momentum. The photo-absorption cross sections for quadrupole radiation in 156 Dy, 160 Er and 164 Er are evaluated within the linear response theory. The strength functions of the γ-ray spectrum obtained from the decay of highly excited nuclear states by deexcitation of the isoscalar quadrupole mode show a fine structure, which depends on the temperature T, the angular momentum I and the deformation of the nucleus β. The splitting of the modes associated with the signature-conserving and signature-changing components of the quadrupole field is discussed. (orig.)

  16. Excitation of Earth Rotation Variations "Observed" by Time-Variable Gravity

    Science.gov (United States)

    Chao, Ben F.; Cox, C. M.

    2005-01-01

    Time variable gravity measurements have been made over the past two decades using the space geodetic technique of satellite laser ranging, and more recently by the GRACE satellite mission with improved spatial resolutions. The degree-2 harmonic components of the time-variable gravity contain important information about the Earth s length-of-day and polar motion excitation functions, in a way independent to the traditional "direct" Earth rotation measurements made by, for example, the very-long-baseline interferometry and GPS. In particular, the (degree=2, order= 1) components give the mass term of the polar motion excitation; the (2,O) component, under certain mass conservation conditions, gives the mass term of the length-of-day excitation. Combining these with yet another independent source of angular momentum estimation calculated from global geophysical fluid models (for example the atmospheric angular momentum, in both mass and motion terms), in principle can lead to new insights into the dynamics, particularly the role or the lack thereof of the cores, in the excitation processes of the Earth rotation variations.

  17. 3-D collapse of rotating stars to Kerr black holes

    International Nuclear Information System (INIS)

    Baiotti, L; Hawke, I; Montero, P J; Loeffler, F L; Rezzolla, L; Stergioulas, N; Font, J A; Seidel, E

    2005-01-01

    We study gravitational collapse of uniformly rotating neutron stars to Kerr black holes, using a new three-dimensional, fully general relativistic hydrodynamics code, which uses high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. We investigate the gravitational collapse by carefully studying not only the dynamics of the matter, but also that of the trapped surfaces, i.e. of both the apparent and event horizons formed during the collapse. The use of these surfaces, together with the dynamical horizon framework, allows for a precise measurement of the black-hole mass and spin. The ability to successfully perform these simulations for sufficiently long times relies on excising a region of the computational domain which includes the singularity and is within the apparent horizon. The dynamics of the collapsing matter is strongly influenced by the initial amount of angular momentum in the progenitor star and, for initial models with sufficiently high angular velocities, the collapse can lead to the formation of an unstable disc in differential rotation

  18. Evidence of nontermination of collective rotation near the maximum angular momentum in Rb75

    Science.gov (United States)

    Davies, P. J.; Afanasjev, A. V.; Wadsworth, R.; Andreoiu, C.; Austin, R. A. E.; Carpenter, M. P.; Dashdorj, D.; Finlay, P.; Freeman, S. J.; Garrett, P. E.; Görgen, A.; Greene, J.; Grinyer, G. F.; Hyland, B.; Jenkins, D. G.; Johnston-Theasby, F. L.; Joshi, P.; Macchiavelli, A. O.; Moore, F.; Mukherjee, G.; Phillips, A. A.; Reviol, W.; Sarantites, D.; Schumaker, M. A.; Seweryniak, D.; Smith, M. B.; Svensson, C. E.; Valiente-Dobon, J. J.; Ward, D.

    2010-12-01

    Two of the four known rotational bands in Rb75 were studied via the Ca40(Ca40,αp)Rb75 reaction at a beam energy of 165 MeV. Transitions were observed up to the maximum spin Imax of the assigned configuration in one case and one-transition short of Imax in the other. Lifetimes were determined using the residual Doppler shift attenuation method. The deduced transition quadrupole moments show a small decrease with increasing spin, but remain large at the highest spins. The results obtained are in good agreement with cranked Nilsson-Strutinsky calculations, which indicate that these rotational bands do not terminate, but remain collective at Imax.

  19. Lumbar segmental instability: a criterion-related validity study of manual therapy assessment

    Directory of Open Access Journals (Sweden)

    Chapple Cathy

    2005-11-01

    Full Text Available Abstract Background Musculoskeletal physiotherapists routinely assess lumbar segmental motion during the clinical examination of a patient with low back pain. The validity of manual assessment of segmental motion has not, however, been adequately investigated. Methods In this prospective, multi-centre, pragmatic, diagnostic validity study, 138 consecutive patients with recurrent or chronic low back pain (R/CLBP were recruited. Physiotherapists with post-graduate training in manual therapy performed passive accessory intervertebral motion tests (PAIVMs and passive physiological intervertebral motion tests (PPIVMs. Consenting patients were referred for flexion-extension radiographs. Sagittal angular rotation and sagittal translation of each lumbar spinal motion segment was measured from these radiographs, and compared to a reference range derived from a study of 30 asymptomatic volunteers. Motion beyond two standard deviations from the reference mean was considered diagnostic of rotational lumbar segmental instability (LSI and translational LSI. Accuracy and validity of the clinical assessments were expressed using sensitivity, specificity, and likelihood ratio statistics with 95% confidence intervals (CI. Results Only translation LSI was found to be significantly associated with R/CLBP (p Conclusion This study provides the first evidence reporting the concurrent validity of manual tests for the detection of abnormal sagittal planar motion. PAIVMs and PPIVMs are highly specific, but not sensitive, for the detection of translation LSI. Likelihood ratios resulting from positive test results were only moderate. This research indicates that manual clinical examination procedures have moderate validity for detecting segmental motion abnormality.

  20. A morphological description of the sagittal otoliths of two mormyrids ...

    African Journals Online (AJOL)

    The morphology of the sagittal otoliths of two South African mormyrid fish, Marcusenius macrolepidotus and Petrocephalus catostoma, were studied to determine possible morphological significance. The sagittae of M. macrolepidotus and P. catostoma are kidney-shaped and oblong, respectively. The ventral margin is ...

  1. Perturbation of a Schwarzschild Black Hole Due to a Rotating Thin Disk

    Energy Technology Data Exchange (ETDEWEB)

    Čížek, P.; Semerák, O., E-mail: oldrich.semerak@mff.cuni.cz [Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic)

    2017-09-01

    Will, in 1974, treated the perturbation of a Schwarzschild black hole due to a slowly rotating, light, concentric thin ring by solving the perturbation equations in terms of a multipole expansion of the mass-and-rotation perturbation series. In the Schwarzschild background, his approach can be generalized to perturbation by a thin disk (which is more relevant astrophysically), but, due to rather bad convergence properties, the resulting expansions are not suitable for specific (numerical) computations. However, we show that Green’s functions, represented by Will’s result, can be expressed in closed form (without multipole expansion), which is more useful. In particular, they can be integrated out over the source (a thin disk in our case) to yield good converging series both for the gravitational potential and for the dragging angular velocity. The procedure is demonstrated, in the first perturbation order, on the simplest case of a constant-density disk, including the physical interpretation of the results in terms of a one-component perfect fluid or a two-component dust in a circular orbit about the central black hole. Free parameters are chosen in such a way that the resulting black hole has zero angular momentum but non-zero angular velocity, as it is just carried along by the dragging effect of the disk.

  2. Sagittal balance, a useful tool for neurosurgeons?

    Science.gov (United States)

    Villard, Jimmy; Ringel, Florian; Meyer, Bernhard

    2014-01-01

    New instrumentation techniques have made any correction of the spinal architecture possible. Sagittal balance has been described as an important parameter for assessing spinal deformity in the early 1970s, but over the last decade its importance has grown with the published results in terms of overall quality of life and fusion rate. Up until now, most of the studies have concentrated on spinal deformity surgery, but its use in the daily neurosurgery practice remains uncertain and may warrant further studies.

  3. The Role of Proprioception in the Sagittal Setting of Anticipatory Postural Adjustments During Gait Initiation

    OpenAIRE

    Pereira Marcelo P.; Pelicioni Paulo H. Silva; Gobbi Lilian T.B.

    2015-01-01

    Purpose. Previous studies have studied the role of proprioception on the setting of anticipatory postural adjustments (APA) during gait initiation. However, these studies did not investigate the role of proprioception in the sagittal APA setting. We aimed to investigate the role of proprioception manipulation to induce APA sagittal adaptations on gait initiation. Methods. Fourteen healthy adults performed gait initiation without, and with, vibration applied before movement onset, and during m...

  4. Usefulness of the dynamic gadolinium-enhanced magnetic resonance imaging with simultaneous acquisition of coronal and sagittal planes for detection of pituitary microadenomas.

    Science.gov (United States)

    Lee, Han Bee; Kim, Sung Tae; Kim, Hyung-Jin; Kim, Keon Ha; Jeon, Pyoung; Byun, Hong Sik; Choi, Jin Wook

    2012-03-01

    Does dynamic gadolinium-enhanced imaging with simultaneous acquisition of coronal and sagittal planes improve diagnostic accuracy of pituitary microadenomas compared with coronal images alone? Fifty-six patients underwent 3-T sella MRI including dynamic simultaneous acquisition of coronal and sagittal planes after gadolinium injection. According to conspicuity, lesions were divided into four scores (0, no; 1, possible; 2, probable; 3, definite delayed enhancing lesion). Additional information on supplementary sagittal images compared with coronal ones was evaluated with a 4-point score (0, no; 1, possible; 2, probable; 3, definite additional information). Accuracy of tumour detection was calculated. Average scores for lesion detection of a combination of two planes, coronal, and sagittal images were 2.59, 2.32, and 2.18. 6/10 lesions negative on coronal images were detected on sagittal ones. Accuracy of a combination of two planes, of coronal and of sagittal images was 92.86%, 82.14% and 75%. Six patients had probable or definite additional information on supplementary sagittal images compared with coronal ones alone (10.71%). Dynamic MRI with combined coronal and sagittal planes was more accurate for detection of pituitary microadenomas than routinely used coronal images. Simultaneous dynamic enhanced acquisition can make study time fast and costs low. We present a new dynamic MRI technique for evaluating pituitary microadenomas • This technique provides simultaneous acquisition of contrast enhanced coronal and sagittal images. • This technique makes the diagnosis more accurate and reduces the examination time. • Such MR imaging only requires one single bolus of contrast agent.

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

    Science.gov (United States)

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

    2018-01-01

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

  6. A general model for preload calculation and stiffness analysis for combined angular contact ball bearings

    Science.gov (United States)

    Zhang, Jinhua; Fang, Bin; Hong, Jun; Wan, Shaoke; Zhu, Yongsheng

    2017-12-01

    The combined angular contact ball bearings are widely used in automatic, aerospace and machine tools, but few researches on the combined angular contact ball bearings have been reported. It is shown that the preload and stiffness of combined bearings are mutual influenced rather than simply the superposition of multiple single bearing, therefore the characteristic calculation of combined bearings achieved by coupling the load and deformation analysis of a single bearing. In this paper, based on the Jones quasi-static model and stiffness analytical model, a new iterative algorithm and model are proposed for the calculation of combined bearings preload and stiffness, and the dynamic effects include centrifugal force and gyroscopic moment have to be considered. It is demonstrated that the new method has general applicability, the preload factors of combined bearings are calculated according to the different design preloads, and the static and dynamic stiffness for various arrangements of combined bearings are comparatively studied and analyzed, and the influences of the design preload magnitude, axial load and rotating speed are discussed in detail. Besides, the change rule of dynamic contact angles of combined bearings with respect to the rotating speed is also discussed. The results show that bearing arrangement modes, rotating speed and design preload magnitude have a significant influence on the preload and stiffness of combined bearings. The proposed formulation provides a useful tool in dynamic analysis of the complex bearing-rotor system.

  7. Angular correlation methods

    International Nuclear Information System (INIS)

    Ferguson, A.J.

    1974-01-01

    An outline of the theory of angular correlations is presented, and the difference between the modern density matrix method and the traditional wave function method is stressed. Comments are offered on particular angular correlation theoretical techniques. A brief discussion is given of recent studies of gamma ray angular correlations of reaction products recoiling with high velocity into vacuum. Two methods for optimization to obtain the most accurate expansion coefficients of the correlation are discussed. (1 figure, 53 references) (U.S.)

  8. Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants

    Science.gov (United States)

    Deheuvels, S.; Doğan, G.; Goupil, M. J.; Appourchaux, T.; Benomar, O.; Bruntt, H.; Campante, T. L.; Casagrande, L.; Ceillier, T.; Davies, G. R.; De Cat, P.; Fu, J. N.; García, R. A.; Lobel, A.; Mosser, B.; Reese, D. R.; Regulo, C.; Schou, J.; Stahn, T.; Thygesen, A. O.; Yang, X. H.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Eggenberger, P.; Gizon, L.; Mathis, S.; Molenda-Żakowicz, J.; Pinsonneault, M.

    2014-04-01

    Context. We still do not understand which physical mechanisms are responsible for the transport of angular momentum inside stars. The recent detection of mixed modes that contain the clear signature of rotation in the spectra of Kepler subgiants and red giants gives us the opportunity to make progress on this question. Aims: Our aim is to probe the radial dependence of the rotation profiles for a sample of Kepler targets. For this purpose, subgiants and early red giants are particularly interesting targets because their rotational splittings are more sensitive to the rotation outside the deeper core than is the case for their more evolved counterparts. Methods: We first extracted the rotational splittings and frequencies of the modes for six young Kepler red giants. We then performed a seismic modeling of these stars using the evolutionary codes Cesam2k and astec. By using the observed splittings and the rotational kernels of the optimal models, we inverted the internal rotation profiles of the six stars. Results: We obtain estimates of the core rotation rates for these stars, and upper limits to the rotation in their convective envelope. We show that the rotation contrast between the core and the envelope increases during the subgiant branch. Our results also suggest that the core of subgiants spins up with time, while their envelope spins down. For two of the stars, we show that a discontinuous rotation profile with a deep discontinuity reproduces the observed splittings significantly better than a smooth rotation profile. Interestingly, the depths that are found to be most probable for the discontinuities roughly coincide with the location of the H-burning shell, which separates the layers that contract from those that expand. Conclusions: We characterized the differential rotation pattern of six young giants with a range of metallicities, and with both radiative and convective cores on the main sequence. This will bring observational constraints to the

  9. Body posture in the sagittal plane and scoliotic variables in girls aged 7-18

    Directory of Open Access Journals (Sweden)

    Jacek Wilczyński

    2018-02-01

    Introduction. The aim of the study was to analyze the correlation between the variable posture in the sagittal plane and the scoliotic variables. Material and methods. The study involved 28 girls aged 7-18 years with scoliotic posture and scoliosis. Body posture as well as the spine were examined using Moiré’s spatial photogrammetry and the Exhibeon digital radiography method. Based on the size of the spinal curvature, the following were distinguished: scoliotic postures: 1-9° and scoliosis: ≥10°. Results. There were 21 (75% with scoliotic posture and 7 (25% with scoliosis. The size of the thoracic kyphosis and lumbar lordosis was normal. Conclusions. Between the body postural variables in the sagittal plane and the scoliotic variables, both positive (direct proportional and negative (inversely proportional correlations occurred. In the selection of scoliosis treatment method, the size of the postural variables in the sagittal plane should be taken into account, and each patient’s case should be individually considered.

  10. Vector correlation analysis for inelastic and reactive collisions between partners possessing spin and orbital angular momentum.

    Science.gov (United States)

    Balint-Kurti, Gabriel G; Vasyutinskii, Oleg S

    2009-12-31

    A general reactive collision of the type A + B --> C + D is considered where both the collision partners (A and B) or the products (C and D) may possess internal, i.e., spin, orbital or rotational, angular momenta. Compact expressions are derived using a rigorous quantum mechanical analysis for the angular momentum anisotropy of either of the products (C or D) arising from an initially polarized distribution of the reactant angular momentum. The angular momentum distribution of the product is expressed in terms of canonical spherical tensors multiplied by anisotropy-transforming coefficients c(K(i)q(k))(K)(K(r),L). These coefficients act as transformation coefficients between the angular momentum anisotropy of the reactants and that of the product. They are independent of scattering angle but depend on the details of the scattering dynamics. The relationship between the coefficients c(K(i)q(k))(K)(K(r),L) and the body-fixed scattering S matrix is given and the methodology for the quantum mechanical calculation of the anisotropy-transforming coefficients is clearly laid out. The anisotropy-transforming coefficients are amenable to direct experimental measurement in a similar manner to vector correlation and alignment parameters in photodissociation processes. A key aspect of the theory is the use of projections of both reactant and product angular momenta onto the product recoil vector direction. An important new conservation rule is revealed through the analysis, namely that if the state multipole for reactant angular momentum distribution has a projection q(k) onto the product recoil vector the state multipoles for the product angular momentum distribution all have this same projection. Expressions are also presented for the distribution of the product angular momentum when its components are evaluated relative to the space-fixed Z-axis. Notes with detailed derivations of all the formulas are available as Supporting Information.

  11. Comparative studies of MRI and operative findings in rotator cuff tear

    International Nuclear Information System (INIS)

    Yamakawa, Seigo; Ichikawa, Norikazu; Itadera, Eichi; Hashizume, Hiroyuki; Inoue, Hajime

    2001-01-01

    A prospective study was performed to determine the accuracy of magnetic resonance imaging (MRI) compared with operative findings in the evaluation of patients associated with rotator cuff tears. Fifty-four of 60 shoulders (58 patients) examined by MRI were confirmed as full-thickness tears and 6 as partial-thickness tears at the time of surgery. The oblique coronal, oblique sagittal, and axial planes of T2-weighted images with the 0.5 tesla MRI system were obtained preoperatively and compared with operative findings. MRI correctly identified 46 of 54 full-thickness rotator cuff tears and 5 of 6 partial-thickness tears. A comparison of MRI and operative findings in full-thickness cuff tears showed a sensitivity of 85%, a specificity of 83%, and a positive prospective value (PPV) of 99%. A comparison of partial-thickness tears showed a sensitivity of 83%, a specificity of 85%, and PPV of 39%. Linear regression analysis showed an excellent correlation between the MRI assessment and measurement at the time of surgery (r=0.90, P<0.01). MRI was useful in evaluating large and medium-sized rotator cuff tears, but less useful in distinguishing small full-thickness tears from partial-thickness tears. (author)

  12. Rotating dilaton black holes with hair

    International Nuclear Information System (INIS)

    Kleihaus, Burkhard; Kunz, Jutta; Navarro-Lerida, Francisco

    2004-01-01

    We consider stationary rotating black holes in SU(2) Einstein-Yang-Mills theory, coupled to a dilaton. The black holes possess nontrivial non-Abelian electric and magnetic fields outside their regular event horizon. While generic solutions carry no non-Abelian magnetic charge, but non-Abelian electric charge, the presence of the dilaton field allows also for rotating solutions with no non-Abelian charge at all. As a consequence, these special solutions do not exhibit the generic asymptotic noninteger power falloff of the non-Abelian gauge field functions. The rotating black hole solutions form sequences, characterized by the winding number n and the node number k of their gauge field functions, tending to embedded Abelian black holes. The stationary non-Abelian black hole solutions satisfy a mass formula, similar to the Smarr formula, where the dilaton charge enters instead of the magnetic charge. Introducing a topological charge, we conjecture that black hole solutions in SU(2) Einstein-Yang-Mills-dilaton theory are uniquely characterized by their mass, their angular momentum, their dilaton charge, their non-Abelian electric charge, and their topological charge

  13. Bilateral sagittal split osteotomy versus distraction osteogenesis for mandibular advancements

    NARCIS (Netherlands)

    Baas, E.M.

    2015-01-01

    The aim of this thesis was to compare the treatment modality of distraction osteogenesis (DO) with the gold standard for mandibular advancement surgery. In fact we compare distraction osteogenesis with the standard of care, which is a conventional bilateral sagittal split osteotomy as described by

  14. Generation of plasma rotation in a tokamak by ion-cyclotron absorption of fast Alfven waves

    International Nuclear Information System (INIS)

    Perkins, F.W.; White, R.B.; Bonoli, P.T.; Chan, V.S.

    2001-01-01

    A mechanism is proposed and evaluated for driving rotation in tokamak plasmas by minority ion-cyclotron heating, even though this heating introduces negligible angular momentum. The mechanism has two elements: First, angular momentum transport is governed by a diffusion equation with a boundary condition at the separatrix. Second, Monte Carlo calculations show that ion-cyclotron energized particles will provide a torque density source which has a zero volume integral but separated positive and negative regions. With such a source, a solution of the diffusion equation predicts that ion-cyclotron heating will cause a rotational shear layer to develop. The corresponding jump in plasma rotation ΔΩ is found to be negative outwards when the ion-cyclotron surface lies on the low-field side of the magnetic axis and positive outwards with the resonance on the high-field side. The magnitude of the jump ΔΩ=(4q max WJ 2 *) (eBR 3 a 2 n e (2π) 2 ) -1 (τ M /τ E ) where |J 2 *|≅2-4 is a nondimensional rotation frequency calculated by the Monte Carlo ORBIT code [R. B. White and M. S. Chance, Phys. Fluids 27, 2455 (1984)]. For a no-slip boundary condition when the resonance lies on the low-field side of the magnetic axis, the sense of predicted axial rotation is co-current and overall agreement with experiment is good. When the resonance lies on the high-field side, the predicted rotation becomes countercurrent for a no-slip boundary while the observed rotation remains co-current. The rotational shear layer position is controllable and of sufficient magnitude to affect microinstabilities

  15. Multichannel singular spectrum analysis of the axial atmospheric angular momentum

    Directory of Open Access Journals (Sweden)

    Leonid Zotov

    2017-11-01

    Full Text Available Earth's variable rotation is mainly produced by the variability of the AAM (atmospheric angular momentum. In particular, the axial AAM component χ3, which undergoes especially strong variations, induces changes in the Earth's rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD (length of day were described. We applied MSSA (Multichannel Singular Spectrum Analysis jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-month, quasi-biennial, 5-year, and low-frequency oscillations. PCs (Principal components strongly related to ENSO (El Nino southern oscillation were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.

  16. High-Q microsphere resonators for angular velocity sensing in gyroscopes

    International Nuclear Information System (INIS)

    An, Panlong; Zheng, Yongqiu; Yan, Shubin; Xue, Chenyang; Liu, Jun; Wang, Wanjun

    2015-01-01

    A resonator gyroscope based on the Sagnac effect is proposed using a core unit that is generated by water-hydrogen flame melting. The relationship between the quality factor Q and diameter D is revealed. The Q factor of the spectral lines of the microsphere cavity coupling system, which uses tapered fibers, is found to be 10 6 or more before packaging with a low refractive curable ultraviolet polymer, although it drops to approximately 10 5 after packaging. In addition, a rotating test platform is built, and the transmission spectrum and discriminator curves of a microsphere cavity with Q of 3.22×10 6 are measured using a semiconductor laser (linewidth less than 1 kHz) and a real-time proportional-integral circuit tracking and feedback technique. Equations fitting the relation between the voltage and angular rotation rate are obtained. According to the experimentally measured parameters, the sensitivity of the microsphere-coupled system can reach 0.095 ∘ /s

  17. Collapse of differentially rotating neutron stars and cosmic censorship

    International Nuclear Information System (INIS)

    Giacomazzo, Bruno; Rezzolla, Luciano; Stergioulas, Nikolaos

    2011-01-01

    We present new results on the dynamics and gravitational-wave emission from the collapse of differentially rotating neutron stars. We have considered a number of polytropic stellar models having different values of the dimensionless angular momentum J/M 2 , where J and M are the asymptotic angular momentum and mass of the star, respectively. For neutron stars with J/M 2 2 >1, i.e. 'supra-Kerr' models, on the other hand, we were not able to find models that are dynamically unstable and all of the computed supra-Kerr models were found to be far from the stability threshold. For these models a gravitational collapse is possible only after a very severe and artificial reduction of the pressure, which then leads to a torus developing nonaxisymmetric instabilities and eventually contracting to a stable axisymmetric stellar configuration. While this does not exclude the possibility that a naked singularity can be produced by the collapse of a differentially rotating star, it also suggests that cosmic censorship is not violated and that generic conditions for a supra-Kerr progenitor do not lead to a naked singularity.

  18. Correlation and Reliability of Cervical Sagittal Alignment Parameters between Lateral Cervical Radiograph and Lateral Whole-Body EOS Stereoradiograph

    Science.gov (United States)

    Singhatanadgige, Weerasak; Kang, Daniel G.; Luksanapruksa, Panya; Peters, Colleen; Riew, K. Daniel

    2015-01-01

    Study Design  Retrospective analysis. Objective  To evaluate the correlation and reliability of cervical sagittal alignment parameters obtained from lateral cervical radiographs (XRs) compared with lateral whole-body stereoradiographs (SRs). Methods  We evaluated adults with cervical deformity using both lateral XRs and lateral SRs obtained within 1 week of each other between 2010 and 2014. XR and SR images were measured by two independent spine surgeons using the following sagittal alignment parameters: C2–C7 sagittal Cobb angle (SCA), C2–C7 sagittal vertical axis (SVA), C1–C7 translational distance (C1–7), T1 slope (T1-S), neck tilt (NT), and thoracic inlet angle (TIA). Pearson correlation and paired t test were used for statistical analysis, with intra- and interrater reliability analyzed using intraclass correlation coefficient (ICC). Results  A total of 35 patients were included in the study. We found excellent intrarater reliability for all sagittal alignment parameters in both the XR and SR groups with ICC ranging from 0.799 to 0.994 for XR and 0.791 to 0.995 for SR. Interrater reliability was also excellent for all parameters except NT and TIA, which had fair reliability. We also found excellent correlations between XR and SR measurements for most sagittal alignment parameters; SCA, SVA, and C1–C7 had r > 0.90, and only NT had r < 0.70. There was a significant difference between groups, with SR having lower measurements compared with XR for both SVA (0.68 cm lower, p < 0.001) and C1–C7 (1.02 cm lower, p < 0.001). There were no differences between groups for SCA, T1-S, NT, and TIA. Conclusion  Whole-body stereoradiography appears to be a viable alternative for measuring cervical sagittal alignment parameters compared with standard radiography. XR and SR demonstrated excellent correlation for most sagittal alignment parameters except NT. However, SR had significantly lower average SVA and C1–C7 measurements than XR

  19. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.L.; Hassam, A.B.; Waltz, R.E.

    1995-01-01

    Stabilization of magnetohydrodynamic ballooning modes by sheared toroidal rotation is demonstrated using a shifted circle equilibrium model. A generalized ballooning mode representation is used to eliminate the fast Alfven wave, and an initial value code solves the resulting equations. The s-α diagram (magnetic shear versus pressure gradient) of ballooning mode theory is extended to include rotational shear. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq, where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and direct stable access to the second stability regime occurs when this frequency is approximately one-quarter to one-half the Alfven frequency, ω A =V A /qR. copyright 1995 American Institute of Physics

  20. The effects of transverse rotation angle on compression and effective lever arm of prosthetic feet during simulated stance.

    Science.gov (United States)

    Major, Matthew J; Howard, David; Jones, Rebecca; Twiste, Martin

    2012-06-01

    Unlike sagittal plane prosthesis alignment, few studies have observed the effects of transverse plane alignment on gait and prosthesis behaviour. Changes in transverse plane rotation angle will rotate the points of loading on the prosthesis during stance and may alter its mechanical behaviour. This study observed the effects of increasing the external transverse plane rotation angle, or toe-out, on foot compression and effective lever arm of three commonly prescribed prosthetic feet. The roll-over shape of a SACH, Flex and single-axis foot was measured at four external rotation angle conditions (0°, 5°, 7° and 12° relative to neutral). Differences in foot compression between conditions were measured as average distance between roll-over shapes. Increasing the transverse plane rotation angle did not affect foot compression. However, it did affect the effective lever arm, which was maximized with the 5° condition, although differences between conditions were small. Increasing the transverse plane rotation angle of prosthetic feet by up to 12° beyond neutral has minimal effects on their mechanical behaviour in the plane of walking progression during weight-bearing.