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.

Low Mach number limits of compressible rotating fluids

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard

2012-01-01

Roč. 14, č. 1 (2012), s. 61-78 ISSN 1422-6928 R&D Projects: GA ČR GA201/08/0315 Institutional research plan: CEZ:AV0Z10190503 Keywords : low Mach number limit * rotating fluid * compressible fluid Subject RIV: BA - General Mathematics Impact factor: 1.415, year: 2012 http://www.springerlink.com/content/635r1116j40t6428/

Daily GPS-Derived Estimates Of Axis Of Rotation Of Earth

Science.gov (United States)

Lindqwister, Ulf J.; Blewitt, Geoffrey; Freedman, Adam

1994-01-01

Report describes study in which data gathered by worldwide network of 21 Global Positioning System (GPS) receivers during 3-week experiment in January and February 1991 used to estimate location of axis of rotation of Earth.

Experimental estimates of quasiparticle interactions for rotational nuclei

International Nuclear Information System (INIS)

Frauendorf, S.; Riedinger, L.L.

1984-01-01

Previously presented data on rotationally aligned quasiparticle bands in sup(160,161,162,163)Yb are analyzed to give experimental values of the quasiparticle interactions Vsub(μν) as a function of rotational frequency. The measured level energies are converted to the rotating frame of reference and expressed as routhians. The routhian of a multi-quasiparticle band is compared to the sum of the routhians of the component quasiparticles at a given frequency, the difference being the quasiparticle interaction. The experimental spectra of bands in these nuclei are consistent with the assumption of a binary interaction between the rotating quasiparticles, where most of the Vsub(μν) are in the range -0.3 to -0.1 MeV. Analysis of the shift in the observed crossing frequencies for bands of different quasiparticle number yields similar values. The extracted Vsub(μν) are found to have a frequency dependence, which is associated with the loss of alignment of a multi-quasiparticle state. An equidistant-level model is used to estimate the contributions to the quasiparticle interactions by polarization of the collective degrees of freedom. This model yields typical Vsub(μν) values of -0.15 MeV, which is only half of some values extracted from experiment. This suggests that the extracted Vsub(μν) contain a significant amount of nuclear-structure information. (orig.)

Rotated Walsh-Hadamard Spreading with Robust Channel Estimation for a Coded MC-CDMA System

Directory of Open Access Journals (Sweden)

Raulefs Ronald

2004-01-01

Full Text Available We investigate rotated Walsh-Hadamard spreading matrices for a broadband MC-CDMA system with robust channel estimation in the synchronous downlink. The similarities between rotated spreading and signal space diversity are outlined. In a multiuser MC-CDMA system, possible performance improvements are based on the chosen detector, the channel code, and its Hamming distance. By applying rotated spreading in comparison to a standard Walsh-Hadamard spreading code, a higher throughput can be achieved. As combining the channel code and the spreading code forms a concatenated code, the overall minimum Hamming distance of the concatenated code increases. This asymptotically results in an improvement of the bit error rate for high signal-to-noise ratio. Higher convolutional channel code rates are mostly generated by puncturing good low-rate channel codes. The overall Hamming distance decreases significantly for the punctured channel codes. Higher channel code rates are favorable for MC-CDMA, as MC-CDMA utilizes diversity more efficiently compared to pure OFDMA. The application of rotated spreading in an MC-CDMA system allows exploiting diversity even further. We demonstrate that the rotated spreading gain is still present for a robust pilot-aided channel estimator. In a well-designed system, rotated spreading extends the performance by using a maximum likelihood detector with robust channel estimation at the receiver by about 1 dB.

An angle-dependent estimation of CT x-ray spectrum from rotational transmission measurements

International Nuclear Information System (INIS)

Lin, Yuan; Samei, Ehsan; Ramirez-Giraldo, Juan Carlos; Gauthier, Daniel J.; Stierstorfer, Karl

2014-01-01

Purpose: Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors propose an angle-dependent estimation technique, where the incident spectra across a wide range of angular trajectories can be estimated accurately with only a single phantom and a single axial scan in the absence of the knowledge of the bowtie filter. Methods: The proposed technique uses a uniform cylindrical phantom, made of ultra-high-molecular-weight polyethylene and positioned in an off-centered geometry. The projection data acquired with an axial scan have a twofold purpose. First, they serve as a reflection of the transmission measurements across different angular trajectories. Second, they are used to reconstruct the cross sectional image of the phantom, which is then utilized to compute the intersection length of each transmission measurement. With each CT detector element recording a range of transmission measurements for a single angular trajectory, the spectrum is estimated for that trajectory. A data conditioning procedure is used to combine information from hundreds of collected transmission measurements to accelerate the estimation speed, to reduce noise, and to improve estimation stability. The proposed spectral estimation technique was validated experimentally using a clinical scanner (Somatom Definition Flash, Siemens Healthcare, Germany) with spectra provided by the manufacturer serving as the comparison standard. Results obtained with the proposed technique were compared against those obtained from a second conventional transmission measurement technique with two materials (i.e., Cu and Al). After validation, the proposed technique was applied to measure

Ground-penetrating radar observations for estimating the vertical displacement of rotational landslides

OpenAIRE

C. Lissak; O. Maquaire; J.-P. Malet; F. Lavigne; C. Virmoux; C. Gomez; R. Davidson

2014-01-01

The objective of this paper is to demonstrate the applicability of Ground Penetrating Radar (GPR) for monitoring the displacement of slow-moving landslides. GPR data is used to estimate the vertical movement of rotational slides in combination with other surveying techniques. The experimental site is located along the Normandy coast (North East France) here several rotational landslides are continuously affected by a seasonal kinematic pattern (low displacem...

Sensorless Estimation and Nonlinear Control of a Rotational Energy Harvester

Science.gov (United States)

Nunna, Kameswarie; Toh, Tzern T.; Mitcheson, Paul D.; Astolfi, Alessandro

2013-12-01

It is important to perform sensorless monitoring of parameters in energy harvesting devices in order to determine the operating states of the system. However, physical measurements of these parameters is often a challenging task due to the unavailability of access points. This paper presents, as an example application, the design of a nonlinear observer and a nonlinear feedback controller for a rotational energy harvester. A dynamic model of a rotational energy harvester with its power electronic interface is derived and validated. This model is then used to design a nonlinear observer and a nonlinear feedback controller which yield a sensorless closed-loop system. The observer estimates the mechancial quantities from the measured electrical quantities while the control law sustains power generation across a range of source rotation speeds. The proposed scheme is assessed through simulations and experiments.

Absorption lines, Faraday rotation, and magnetic field estimates for QSO absorption-line clouds

International Nuclear Information System (INIS)

Kronberg, P.P.; Perry, J.J.

1982-01-01

We have estimated the extragalactic component of Faraday rotation for a sample of 37 QSOs for which there is good absorption line data, which we have also analyzed. Statistical evidence is presented which suggests that we have isolated a component of Faraday rotation which is occurring in the absorption clouds of some QSOs

Three-hair relations for rotating stars: Nonrelativistic limit

Energy Technology Data Exchange (ETDEWEB)

Stein, Leo C. [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States); Yagi, Kent; Yunes, Nicolás, E-mail: leostein@astro.cornell.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2014-06-10

The gravitational field outside of astrophysical black holes is completely described by their mass and spin frequency, as expressed by the no-hair theorems. These theorems assume vacuum spacetimes, and thus they apply only to black holes and not to stars. Despite this, we analytically find that the gravitational potential of arbitrarily rapid, rigidly rotating stars can still be described completely by only their mass, spin angular momentum, and quadrupole moment. Although these results are obtained in the nonrelativistic limit (to leading order in a weak-field expansion of general relativity, GR), they are also consistent with fully relativistic numerical calculations of rotating neutron stars. This description of the gravitational potential outside the source in terms of just three quantities is approximately universal (independent of equation of state). Such universality may be used to break degeneracies in pulsar and future gravitational wave observations to extract more physics and test GR in the strong-field regime.

Effective theory of rotationally faulted multilayer graphene - the local limit

International Nuclear Information System (INIS)

Kindermann, M; First, P N

2012-01-01

Interlayer coupling in rotationally faulted graphene multilayers breaks the local sublattice-symmetry of the individual layers. Earlier we have presented a theory of this mechanism, which reduces to an effective Dirac model with space-dependent mass in an important limit. It thus makes a wealth of existing knowledge available for the study of rotationally faulted graphene multilayers. Agreement of this theory with a recent experiment in a strong magnetic field was demonstrated. Here we explore some of the predictions of this theory for the system in zero magnetic field at large interlayer bias, when it becomes local in space. We use that theory to illuminate the physics of localization and velocity renormalization in twisted graphene layers. (paper)

Using NDVI to estimate carbon fluxes from small rotationally grazed pastures

Science.gov (United States)

Satellite-based Normalized Difference Vegetation Index (NDVI) data have been extensively used for estimating gross primary productivity (GPP) and yield of grazing lands throughout the world. However, the usefulness of satellite-based images for monitoring rotationally-grazed pastures in the northea...

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.

Calibrated Tully-Fisher relations for improved estimates of disc rotation velocities

NARCIS (Netherlands)

Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno II, Jim; Lackner, C. N.

2011-01-01

In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity V-rot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of V-rot applicable to large galaxy

High precision estimation of inertial rotation via the extended Kalman filter

Science.gov (United States)

Liu, Lijun; Qi, Bo; Cheng, Shuming; Xi, Zairong

2015-11-01

Recent developments in technology have enabled atomic gyroscopes to become the most sensitive inertial sensors. Atomic spin gyroscopes essentially output an estimate of the inertial rotation rate to be measured. In this paper, we present a simple yet efficient estimation method, the extended Kalman filter (EKF), for the atomic spin gyroscope. Numerical results show that the EKF method is much more accurate than the steady-state estimation method, which is used in the most sensitive atomic gyroscopes at present. Specifically, the root-mean-squared errors obtained by the EKF method are at least 103 times smaller than those obtained by the steady-state estimation method under the same response time.

Estimating uncertainty of data limited stock assessments

DEFF Research Database (Denmark)

Kokkalis, Alexandros; Eikeset, Anne Maria; Thygesen, Uffe Høgsbro

2017-01-01

-limited. Particular emphasis is put on providing uncertainty estimates of the data-limited assessment. We assess four cod stocks in the North-East Atlantic and compare our estimates of stock status (F/Fmsy) with the official assessments. The estimated stock status of all four cod stocks followed the established stock...

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

1999-01-01

In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belo...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion......In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Rotational electrical impedance tomography using electrodes with limited surface coverage provides window for multimodal sensing

Science.gov (United States)

Lehti-Polojärvi, Mari; Koskela, Olli; Seppänen, Aku; Figueiras, Edite; Hyttinen, Jari

2018-02-01

Electrical impedance tomography (EIT) is an imaging method that could become a valuable tool in multimodal applications. One challenge in simultaneous multimodal imaging is that typically the EIT electrodes cover a large portion of the object surface. This paper investigates the feasibility of rotational EIT (rEIT) in applications where electrodes cover only a limited angle of the surface of the object. In the studied rEIT, the object is rotated a full 360° during a set of measurements to increase the information content of the data. We call this approach limited angle full revolution rEIT (LAFR-rEIT). We test LAFR-rEIT setups in two-dimensional geometries with computational and experimental data. We use up to 256 rotational measurement positions, which requires a new way to solve the forward and inverse problem of rEIT. For this, we provide a modification, available for EIDORS, in the supplementary material. The computational results demonstrate that LAFR-rEIT with eight electrodes produce the same image quality as conventional 16-electrode rEIT, when data from an adequate number of rotational measurement positions are used. Both computational and experimental results indicate that the novel LAFR-rEIT provides good EIT with setups with limited surface coverage and a small number of electrodes.

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

2001-01-01

In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong ...... approximations to the Riemannian metric, and that the subsequent corrections are inherent in the least squares estimation.......In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Peer influence on students' estimates of performance : social comparison in clinical rotations

NARCIS (Netherlands)

Raat, A. N. (Janet); Kuks, Jan B. M.; van Hell, E. Ally; Cohen-Schotanus, Janke

Context During clinical rotations, students move from one clinical situation to another. Questions exist about students strategies for coping with these transitions. These strategies may include a process of social comparison because in this context it offers the student an opportunity to estimate

Calibrated Tully-fisher Relations For Improved Photometric Estimates Of Disk Rotation Velocities

Science.gov (United States)

Reyes, Reinabelle; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.

2011-01-01

We present calibrated scaling relations (also referred to as Tully-Fisher relations or TFRs) between rotation velocity and photometric quantities-- absolute magnitude, stellar mass, and synthetic magnitude (a linear combination of absolute magnitude and color)-- of disk galaxies at z 0.1. First, we selected a parent disk sample of 170,000 galaxies from SDSS DR7, with redshifts between 0.02 and 0.10 and r band absolute magnitudes between -18.0 and -22.5. Then, we constructed a child disk sample of 189 galaxies that span the parameter space-- in absolute magnitude, color, and disk size-- covered by the parent sample, and for which we have obtained kinematic data. Long-slit spectroscopy were obtained from the Dual Imaging Spectrograph (DIS) at the Apache Point Observatory 3.5 m for 99 galaxies, and from Pizagno et al. (2007) for 95 galaxies (five have repeat observations). We find the best photometric estimator of disk rotation velocity to be a synthetic magnitude with a color correction that is consistent with the Bell et al. (2003) color-based stellar mass ratio. The improved rotation velocity estimates have a wide range of scientific applications, and in particular, in combination with weak lensing measurements, they enable us to constrain the ratio of optical-to-virial velocity in disk galaxies.

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.

Abduction and external rotation (ABER) MR arthrography of the shoulder. Benefits and limitations

International Nuclear Information System (INIS)

Mostafa, A.; Gokan, Takehiko; Munechika, Hirotsugu; Ogawa, Takashi; El-Feky, A.A.

2001-01-01

The purpose of this study was to show the benefits and limitations of using abduction and external rotation (ABER) positions of the arm during MR arthrography of the shoulder in the evaluation of the rotator-cuff tendon, the capsulolabral complex and the shoulder joint after surgery. Forty-seven patients complaining of either shoulder instability, chronic shoulder pain, pain of unknown cause or pain following shoulder surgery were studied using the direct MR arthrography technique in both the standard neutral position with the arm adducted as well as with the arm in the ABER position. A correlation was obtained between the MR arthrography findings and the surgical findings in 10 reports and clinical presentations of the examined patients. Three patients [6%] were unable to perform ABER positioning. ABER oblique axial images were better than standard oblique coronal images in revealing undersurface tears of the rotator cuff particularly of the grade I type. Four tears were missed in standard images. Oblique axial images were better than standard axial images in demonstrating non-displaced anterior labral tears. One tear was missed and two tears were suspected in the standard images. Oblique axial images were less sensitive than oblique coronal images in the diagnosis of superior labral tears. Two tears were missed in ABER images. The ABER oblique axial MR arthrogram is a useful adjunct to the standard axial and oblique coronal MR arthrograms for assessment of capsulolabral abnormalities and rotator-cuff tendon tears despite some limitations. (author)

Estimating the time evolution of NMR systems via a quantum-speed-limit-like expression

Science.gov (United States)

Villamizar, D. V.; Duzzioni, E. I.; Leal, A. C. S.; Auccaise, R.

2018-05-01

Finding the solutions of the equations that describe the dynamics of a given physical system is crucial in order to obtain important information about its evolution. However, by using estimation theory, it is possible to obtain, under certain limitations, some information on its dynamics. The quantum-speed-limit (QSL) theory was originally used to estimate the shortest time in which a Hamiltonian drives an initial state to a final one for a given fidelity. Using the QSL theory in a slightly different way, we are able to estimate the running time of a given quantum process. For that purpose, we impose the saturation of the Anandan-Aharonov bound in a rotating frame of reference where the state of the system travels slower than in the original frame (laboratory frame). Through this procedure it is possible to estimate the actual evolution time in the laboratory frame of reference with good accuracy when compared to previous methods. Our method is tested successfully to predict the time spent in the evolution of nuclear spins 1/2 and 3/2 in NMR systems. We find that the estimated time according to our method is better than previous approaches by up to four orders of magnitude. One disadvantage of our method is that we need to solve a number of transcendental equations, which increases with the system dimension and parameter discretization used to solve such equations numerically.

Generalized allometric regression to estimate biomass of Populus in short-rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Ben Brahim, Mohammed; Gavaland, Andre; Cabanettes, Alain [INRA Centre de Toulouse, Castanet-Tolosane Cedex (France). Unite Agroforesterie et Foret Paysanne

2000-07-01

Data from four different stands were combined to establish a single generalized allometric equation to estimate above-ground biomass of individual Populus trees grown on short-rotation coppice. The generalized model was performed using diameter at breast height, the mean diameter and the mean height of each site as dependent variables and then compared with the stand-specific regressions using F-test. Results showed that this single regression estimates tree biomass well at each stand and does not introduce bias with increasing diameter.

Rotating Parabolic-Reflector Antenna Target in SAR Data: Model, Characteristics, and Parameter Estimation

Directory of Open Access Journals (Sweden)

Bin Deng

2013-01-01

Full Text Available Parabolic-reflector antennas (PRAs, usually possessing rotation, are a particular type of targets of potential interest to the synthetic aperture radar (SAR community. This paper is aimed to investigate PRA’s scattering characteristics and then to extract PRA’s parameters from SAR returns, for supporting image interpretation and target recognition. We at first obtain both closed-form and numeric solutions to PRA’s backscattering by geometrical optics (GO, physical optics, and graphical electromagnetic computation, respectively. Based on the GO solution, a migratory scattering center model is at first presented for representing the movement of the specular point with aspect angle, and then a hybrid model, named the migratory/micromotion scattering center (MMSC model, is proposed for characterizing a rotating PRA in the SAR geometry, which incorporates PRA’s rotation into its migratory scattering center model. Additionally, we in detail analyze PRA’s radar characteristics on radar cross-section, high-resolution range profiles, time-frequency distribution, and 2D images, which also confirm the models proposed. A maximal likelihood estimator is developed for jointly solving the MMSC model for PRA’s multiple parameters by optimization. By exploiting the aforementioned characteristics, the coarse parameter estimation guarantees convergency upon global minima. The signatures recovered can be favorably utilized for SAR image interpretation and target recognition.

You Spin my Head Right Round: Threshold of Limited Immersion for Rotation Gains in Redirected Walking.

Science.gov (United States)

Schmitz, Patric; Hildebrandt, Julian; Valdez, Andre Calero; Kobbelt, Leif; Ziefle, Martina

2018-04-01

In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

The optical rotator

DEFF Research Database (Denmark)

Tandrup, T; Gundersen, Hans Jørgen Gottlieb; Jensen, Eva B. Vedel

1997-01-01

further discuss the methods derived from this principle and present two new local volume estimators. The optical rotator benefits from information obtained in all three dimensions in thick sections but avoids over-/ underprojection problems at the extremes of the cell. Using computer-assisted microscopes......The optical rotator is an unbiased, local stereological principle for estimation of cell volume and cell surface area in thick, transparent slabs, The underlying principle was first described in 1993 by Kieu Jensen (T. Microsc. 170, 45-51) who also derived an estimator of length, In this study we...... the extra measurements demand minimal extra effort and make this estimator even more efficient when it comes to estimation of individual cell size than many of the previous local estimators, We demonstrate the principle of the optical rotator in an example (the cells in the dorsal root ganglion of the rat...

Effect of Medium Symmetries in Limiting the Number of Parameters Estimated with Polarimetric Interferometry

Science.gov (United States)

Moghaddam, Mahta

2000-01-01

The addition of interferometric backscattering pairs to the conventional polarimetric SAR data over forests and other vegetated areas increases the dimensionality of the data space, in principle enabling the estimation of a larger number of vegetation parameters. Without regard to the sensitivity of these data to vegetation scattering parameters, this paper poses the question: Will increasing the data channels as such result in a one-to-one increase in the number of parameters that can be estimated, or do vegetation and data properties inherently limit that number otherwise? In this paper, the complete polarimetric interferometric covariance matrix is considered and various symmetry properties of the scattering medium are used to study whether any of the correlation pairs can be eliminated. The number of independent pairs has direct consequences in their utility in parameter estimation schemes, since the maximum number of parameters that can be estimated cannot exceed the number of unique measurements. The independent components of the polarimetric interferometric SAR (POL/INSAR) data are derived for media with reflection, rotation, and azimuth symmetries, which are often encountered in vegetated surfaces. Similar derivations have been carried out before for simple polarimetry, i.e., zero baseline. This paper extends those to the interferometric case of general nonzero baselines. It is shown that depending on the type of symmetries present, the number of independent available measurements that can be used to estimate medium parameters will vary. In particular, whereas in the general case there are 27 mathematically independent measurements possible from a polarimetric interferometer, this number can be reduced to 15, 9, and 6 if the medium has reflection, rotation, or azimuthal symmetries, respectively. The results can be used in several ways in the interpretation of SAR data and the development of parameter estimation schemes, which will be discussed at the

Validity of eyeball estimation for range of motion during the cervical flexion rotation test compared to an ultrasound-based movement analysis system.

Science.gov (United States)

Schäfer, Axel; Lüdtke, Kerstin; Breuel, Franziska; Gerloff, Nikolas; Knust, Maren; Kollitsch, Christian; Laukart, Alex; Matej, Laura; Müller, Antje; Schöttker-Königer, Thomas; Hall, Toby

2018-08-01

Headache is a common and costly health problem. Although pathogenesis of headache is heterogeneous, one reported contributing factor is dysfunction of the upper cervical spine. The flexion rotation test (FRT) is a commonly used diagnostic test to detect upper cervical movement impairment. The aim of this cross-sectional study was to investigate concurrent validity of detecting high cervical ROM impairment during the FRT by comparing measurements established by an ultrasound-based system (gold standard) with eyeball estimation. Secondary aim was to investigate intra-rater reliability of FRT ROM eyeball estimation. The examiner (6 years experience) was blinded to the data from the ultrasound-based device and to the symptoms of the patients. FRT test result (positive or negative) was based on visual estimation of range of rotation less than 34° to either side. Concurrently, range of rotation was evaluated using the ultrasound-based device. A total of 43 subjects with headache (79% female), mean age of 35.05 years (SD 13.26) were included. According to the International Headache Society Classification 23 subjects had migraine, 4 tension type headache, and 16 multiple headache forms. Sensitivity and specificity were 0.96 and 0.89 for combined rotation, indicating good concurrent reliability. The area under the ROC curve was 0.95 (95% CI 0.91-0.98) for rotation to both sides. Intra-rater reliability for eyeball estimation was excellent with Fleiss Kappa 0.79 for right rotation and left rotation. The results of this study indicate that the FRT is a valid and reliable test to detect impairment of upper cervical ROM in patients with headache.

DOA and Noncircular Phase Estimation of Noncircular Signal via an Improved Noncircular Rotational Invariance Propagator Method

Directory of Open Access Journals (Sweden)

Xueqiang Chen

2015-01-01

Full Text Available We consider the computationally efficient direction-of-arrival (DOA and noncircular (NC phase estimation problem of noncircular signal for uniform linear array. The key idea is to apply the noncircular propagator method (NC-PM which does not require eigenvalue decomposition (EVD of the covariance matrix or singular value decomposition (SVD of the received data. Noncircular rotational invariance propagator method (NC-RI-PM avoids spectral peak searching in PM and can obtain the closed-form solution of DOA, so it has lower computational complexity. An improved NC-RI-PM algorithm of noncircular signal for uniform linear array is proposed to estimate the elevation angles and noncircular phases with automatic pairing. We reconstruct the extended array output by combining the array output and its conjugated counterpart. Our algorithm fully uses the extended array elements in the improved propagator matrix to estimate the elevation angles and noncircular phases by utilizing the rotational invariance property between subarrays. Compared with NC-RI-PM, the proposed algorithm has better angle estimation performance and much lower computational load. The computational complexity of the proposed algorithm is analyzed. We also derive the variance of estimation error and Cramer-Rao bound (CRB of noncircular signal for uniform linear array. Finally, simulation results are presented to demonstrate the effectiveness of our algorithm.

Space-Frequency Block Code with Matched Rotation for MIMO-OFDM System with Limited Feedback

Directory of Open Access Journals (Sweden)

Thushara D. Abhayapala

2009-01-01

Full Text Available This paper presents a novel matched rotation precoding (MRP scheme to design a rate one space-frequency block code (SFBC and a multirate SFBC for MIMO-OFDM systems with limited feedback. The proposed rate one MRP and multirate MRP can always achieve full transmit diversity and optimal system performance for arbitrary number of antennas, subcarrier intervals, and subcarrier groupings, with limited channel knowledge required by the transmit antennas. The optimization process of the rate one MRP is simple and easily visualized so that the optimal rotation angle can be derived explicitly, or even intuitively for some cases. The multirate MRP has a complex optimization process, but it has a better spectral efficiency and provides a relatively smooth balance between system performance and transmission rate. Simulations show that the proposed SFBC with MRP can overcome the diversity loss for specific propagation scenarios, always improve the system performance, and demonstrate flexible performance with large performance gain. Therefore the proposed SFBCs with MRP demonstrate flexibility and feasibility so that it is more suitable for a practical MIMO-OFDM system with dynamic parameters.

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.

Inertial modes of rigidly rotating neutron stars in Cowling approximation

International Nuclear Information System (INIS)

Kastaun, Wolfgang

2008-01-01

In this article, we investigate inertial modes of rigidly rotating neutron stars, i.e. modes for which the Coriolis force is dominant. This is done using the assumption of a fixed spacetime (Cowling approximation). We present frequencies and eigenfunctions for a sequence of stars with a polytropic equation of state, covering a broad range of rotation rates. The modes were obtained with a nonlinear general relativistic hydrodynamic evolution code. We further show that the eigenequations for the oscillation modes can be written in a particularly simple form for the case of arbitrary fast but rigid rotation. Using these equations, we investigate some general characteristics of inertial modes, which are then compared to the numerically obtained eigenfunctions. In particular, we derive a rough analytical estimate for the frequency as a function of the number of nodes of the eigenfunction, and find that a similar empirical relation matches the numerical results with unexpected accuracy. We investigate the slow rotation limit of the eigenequations, obtaining two different sets of equations describing pressure and inertial modes. For the numerical computations we only considered axisymmetric modes, while the analytic part also covers nonaxisymmetric modes. The eigenfunctions suggest that the classification of inertial modes by the quantum numbers of the leading term of a spherical harmonic decomposition is artificial in the sense that the largest term is not strongly dominant, even in the slow rotation limit. The reason for the different structure of pressure and inertial modes is that the Coriolis force remains important in the slow rotation limit only for inertial modes. Accordingly, the scalar eigenequation we obtain in that limit is spherically symmetric for pressure modes, but not for inertial modes

Viscosity estimation utilizing flow velocity field measurements in a rotating magnetized plasma

International Nuclear Information System (INIS)

Yoshimura, Shinji; Tanaka, Masayoshi Y.

2008-01-01

The importance of viscosity in determining plasma flow structures has been widely recognized. In laboratory plasmas, however, viscosity measurements have been seldom performed so far. In this paper we present and discuss an estimation method of effective plasma kinematic viscosity utilizing flow velocity field measurements. Imposing steady and axisymmetric conditions, we derive the expression for radial flow velocity from the azimuthal component of the ion fluid equation. The expression contains kinematic viscosity, vorticity of azimuthal rotation and its derivative, collision frequency, azimuthal flow velocity and ion cyclotron frequency. Therefore all quantities except the viscosity are given provided that the flow field can be measured. We applied this method to a rotating magnetized argon plasma produced by the Hyper-I device. The flow velocity field measurements were carried out using a directional Langmuir probe installed in a tilting motor drive unit. The inward ion flow in radial direction, which is not driven in collisionless inviscid plasmas, was clearly observed. As a result, we found the anomalous viscosity, the value of which is two orders of magnitude larger than the classical one. (author)

Magnetometer and Gyroscope Calibration Method with Level Rotation

Directory of Open Access Journals (Sweden)

Zongkai Wu

2018-03-01

Full Text Available Micro electro mechanical system (MEMS gyroscopes and magnetometers are usually integrated into a sensor module or chip and widely used in a variety of applications. In existing integrated gyroscope and magnetometer calibration methods, rotation in all possible orientations is a necessary condition for a good calibration result. However, rotation around two or more axes is difficult to attain, as it is limited by the range of movement of vehicles such as cars, ships, or planes. To solve this problem, this paper proposes an integrated magnetometer and gyroscope calibration method with level rotation. The proposed method presents a redefined magnetometer output model using level attitude. New gyroscope and magnetometer calibration models are then deduced. In addition, a simplified cubature Kalman filter (CKF is established to estimate calibration parameters. This method possesses important value for application in actual systems, as it only needs level rotation for real-time calibration of gyroscopes and magnetometers. Theoretical analysis and test results verify the validity and feasibility of this method.

Real-time estimation of prostate tumor rotation and translation with a kV imaging system based on an iterative closest point algorithm

International Nuclear Information System (INIS)

Tehrani, Joubin Nasehi; O’Brien, Ricky T; Keall, Paul; Poulsen, Per Rugaard

2013-01-01

Previous studies have shown that during cancer radiotherapy a small translation or rotation of the tumor can lead to errors in dose delivery. Current best practice in radiotherapy accounts for tumor translations, but is unable to address rotation due to a lack of a reliable real-time estimate. We have developed a method based on the iterative closest point (ICP) algorithm that can compute rotation from kilovoltage x-ray images acquired during radiation treatment delivery. A total of 11 748 kilovoltage (kV) images acquired from ten patients (one fraction for each patient) were used to evaluate our tumor rotation algorithm. For each kV image, the three dimensional coordinates of three fiducial markers inside the prostate were calculated. The three dimensional coordinates were used as input to the ICP algorithm to calculate the real-time tumor rotation and translation around three axes. The results show that the root mean square error was improved for real-time calculation of tumor displacement from a mean of 0.97 mm with the stand alone translation to a mean of 0.16 mm by adding real-time rotation and translation displacement with the ICP algorithm. The standard deviation (SD) of rotation for the ten patients was 2.3°, 0.89° and 0.72° for rotation around the right–left (RL), anterior–posterior (AP) and superior–inferior (SI) directions respectively. The correlation between all six degrees of freedom showed that the highest correlation belonged to the AP and SI translation with a correlation of 0.67. The second highest correlation in our study was between the rotation around RL and rotation around AP, with a correlation of −0.33. Our real-time algorithm for calculation of rotation also confirms previous studies that have shown the maximum SD belongs to AP translation and rotation around RL. ICP is a reliable and fast algorithm for estimating real-time tumor rotation which could create a pathway to investigational clinical treatment studies requiring

A Model of Polarisation Rotations in Blazars from Kink Instabilities in Relativistic Jets

Directory of Open Access Journals (Sweden)

Krzysztof Nalewajko

2017-10-01

Full Text Available This paper presents a simple model of polarisation rotation in optically thin relativistic jets of blazars. The model is based on the development of helical (kink mode of current-driven instability. A possible explanation is suggested for the observational connection between polarisation rotations and optical/gamma-ray flares in blazars, if the current-driven modes are triggered by secular increases of the total jet power. The importance of intrinsic depolarisation in limiting the amplitude of coherent polarisation rotations is demonstrated. The polarisation rotation amplitude is thus very sensitive to the viewing angle, which appears to be inconsistent with the observational estimates of viewing angles in blazars showing polarisation rotations. Overall, there are serious obstacles to explaining large-amplitude polarisation rotations in blazars in terms of current-driven kink modes.

The spatial rotator

DEFF Research Database (Denmark)

Rasmusson, Allan; Hahn, Ute; Larsen, Jytte Overgaard

2013-01-01

This paper presents a new local volume estimator, the spatial rotator, which is based on measurements on a virtual 3D probe, using computer assisted microscopy. The basic design of the probe builds upon the rotator principle which requires only a few manual intersection markings, thus making...

Estimation of optical rotation of γ-alkylidenebutenolide, cyclopropylamine, cyclopropyl-methanol and cyclopropenone based compounds by a Density Functional Theory (DFT) approach.

Science.gov (United States)

Shahzadi, Iram; Shaukat, Aqsa; Zara, Zeenat; Irfan, Muhammad; Eliasson, Bertil; Ayub, Khurshid; Iqbal, Javed

2017-10-01

Computing the optical rotation of organic molecules can be a real challenge, and various theoretical approaches have been developed in this regard. A benchmark study of optical rotation of various classes of compounds was carried out by Density Functional Theory (DFT) methods. The aim of the present research study was to find out the best-suited functional and basis set to estimate the optical rotations of selected compounds with respect to experimental literature values. Six DFT functional LSDA, BVP86, CAM-B3LYP, B3PW91, and PBE were applied on 22 different compounds. Furthermore, six different basis sets, i.e., 3-21G, 6-31G, aug-cc-pVDZ, aug-cc-pVTZ, DGDZVP, and DGDZVP2 were also applied with the best-suited functional B3LYP. After rigorous effort, it can be safely said that the best combination of functional and basis set is B3LYP/aug-cc-pVTZ for the estimation of optical rotation for selected compounds. © 2017 Wiley Periodicals, Inc.

Strong gravitational lensing by a Konoplya-Zhidenko rotating non-Kerr compact object

Energy Technology Data Exchange (ETDEWEB)

Wang, Shangyun; Chen, Songbai; Jing, Jiliang, E-mail: shangyun_wang@163.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)

2016-11-01

Konoplya and Zhidenko have proposed recently a rotating non-Kerr black hole metric beyond General Relativity and make an estimate for the possible deviations from the Kerr solution with the data of GW 150914. We here study the strong gravitational lensing in such a rotating non-Kerr spacetime with an extra deformation parameter. We find that the condition of existence of horizons is not inconsistent with that of the marginally circular photon orbit. Moreover, the deflection angle of the light ray near the weakly naked singularity covered by the marginally circular orbit diverges logarithmically in the strong-field limit. In the case of the completely naked singularity, the deflection angle near the singularity tends to a certain finite value, whose sign depends on the rotation parameter and the deformation parameter. These properties of strong gravitational lensing are different from those in the Johannsen-Psaltis rotating non-Kerr spacetime and in the Janis-Newman-Winicour spacetime. Modeling the supermassive central object of the Milk Way Galaxy as a Konoplya-Zhidenko rotating non-Kerr compact object, we estimated the numerical values of observables for the strong gravitational lensing including the time delay between two relativistic images.

Particle Trajectories in Rotating Wall Cell Culture Devices

Science.gov (United States)

Ramachandran N.; Downey, J. P.

1999-01-01

Cell cultures are extremely important to the medical community since such cultures provide an opportunity to perform research on human tissue without the concerns inherent in experiments on individual humans. Development of cells in cultures has been found to be greatly influenced by the conditions of the culture. Much work has focused on the effect of the motions of cells in the culture relative to the solution. Recently rotating wall vessels have been used with success in achieving improved cellular cultures. Speculation and limited research have focused on the low shear environment and the ability of rotating vessels to keep cells suspended in solution rather than floating or sedimenting as the primary reasons for the improved cellular cultures using these devices. It is widely believed that the cultures obtained using a rotating wall vessel simulates to some degree the effect of microgravity on cultures. It has also been speculated that the microgravity environment may provide the ideal acceleration environment for culturing of cellular tissues due to the nearly negligible levels of sedimentation and shear possible. This work predicts particle trajectories of cells in rotating wall vessels of cylindrical and annular design consistent with the estimated properties of typical cellular cultures. Estimates of the shear encountered by cells in solution and the interactions with walls are studied. Comparisons of potential experiments in ground and microgravity environments are performed.

Rotational Spectrum of 1,1-Difluoroethane: Internal Rotation Analysis and Structure

Science.gov (United States)

Villamanan, R. M.; Chen, W. D.; Wlodarczak, G.; Demaison, J.; Lesarri, A. G.; Lopez, J. C.; Alonso, J. L.

1995-05-01

The rotational spectrum of CH3CHF2 in its ground state was measured up to 653 GHz. Accurate rotational and centrifugal distortion constants were determined. The internal rotation splittings were analyzed using the internal axis method. An ab initio structure has been calculated and a near-equilibrium structure has been estimated using offsets derived empirically. This structure was compared to an experimental r0 structure. The four lowest excited states (including the methyl torsion) have also been assigned.

Global rotational motion and displacement estimation of digital image stabilization based on the oblique vectors matching algorithm

Science.gov (United States)

Yu, Fei; Hui, Mei; Zhao, Yue-jin

2009-08-01

The image block matching algorithm based on motion vectors of correlative pixels in oblique direction is presented for digital image stabilization. The digital image stabilization is a new generation of image stabilization technique which can obtains the information of relative motion among frames of dynamic image sequences by the method of digital image processing. In this method the matching parameters are calculated from the vectors projected in the oblique direction. The matching parameters based on the vectors contain the information of vectors in transverse and vertical direction in the image blocks at the same time. So the better matching information can be obtained after making correlative operation in the oblique direction. And an iterative weighted least square method is used to eliminate the error of block matching. The weights are related with the pixels' rotational angle. The center of rotation and the global emotion estimation of the shaking image can be obtained by the weighted least square from the estimation of each block chosen evenly from the image. Then, the shaking image can be stabilized with the center of rotation and the global emotion estimation. Also, the algorithm can run at real time by the method of simulated annealing in searching method of block matching. An image processing system based on DSP was used to exam this algorithm. The core processor in the DSP system is TMS320C6416 of TI, and the CCD camera with definition of 720×576 pixels was chosen as the input video signal. Experimental results show that the algorithm can be performed at the real time processing system and have an accurate matching precision.

Limitations of rotational manoeuvrability in insects and hummingbirds: evaluating the effects of neuro-biomechanical delays and muscle mechanical power.

Science.gov (United States)

Liu, Pan; Cheng, Bo

2017-07-01

Flying animals ranging in size from fruit flies to hummingbirds are nimble fliers with remarkable rotational manoeuvrability. The degrees of manoeuvrability among these animals, however, are noticeably diverse and do not simply follow scaling rules of flight dynamics or muscle power capacity. As all manoeuvres emerge from the complex interactions of neural, physiological and biomechanical processes of an animal's flight control system, these processes give rise to multiple limiting factors that dictate the maximal manoeuvrability attainable by an animal. Here using functional models of an animal's flight control system, we investigate the effects of three such limiting factors, including neural and biomechanical (from limited flapping frequency) delays and muscle mechanical power, for two insect species and two hummingbird species, undergoing roll, pitch and yaw rotations. The results show that for animals with similar degree of manoeuvrability, for example, fruit flies and hummingbirds, the underlying limiting factors are different, as the manoeuvrability of fruit flies is only limited by neural delays and that of hummingbirds could be limited by all three factors. In addition, the manoeuvrability also appears to be the highest about the roll axis as it requires the least muscle mechanical power and can tolerate the largest neural delays. © 2017 The Author(s).

Limiting diffusion current at rotating disk electrode with dense particle layer.

Science.gov (United States)

Weroński, P; Nosek, M; Batys, P

2013-09-28

Exploiting the concept of diffusion permeability of multilayer gel membrane and porous multilayer we have derived a simple analytical equation for the limiting diffusion current at rotating disk electrode (RDE) covered by a thin layer with variable tortuosity and porosity, under the assumption of negligible convection in the porous film. The variation of limiting diffusion current with the porosity and tortuosity of the film can be described in terms of the equivalent thickness of stagnant solution layer, i.e., the average ratio of squared tortuosity to porosity. In case of monolayer of monodisperse spherical particles, the equivalent layer thickness is an algebraic function of the surface coverage. Thus, by means of cyclic voltammetry of RDE with a deposited particle monolayer we can determine the monolayer surface coverage. The effect of particle layer adsorbed on the surface of RDE increases non-linearly with surface coverage. We have tested our theoretical results experimentally by means of cyclic voltammetry measurements of limiting diffusion current at the glassy carbon RDE covered with a monolayer of 3 μm silica particles. The theoretical and experimental results are in a good agreement at the surface coverage higher than 0.7. This result suggests that convection in a monolayer of 3 μm monodisperse spherical particles is negligibly small, in the context of the coverage determination, in the range of very dense particle layers.

Estimation of the center of rotation using wearable magneto-inertial sensors.

Science.gov (United States)

Crabolu, M; Pani, D; Raffo, L; Cereatti, A

2016-12-08

Determining the center of rotation (CoR) of joints is fundamental to the field of human movement analysis. CoR can be determined using a magneto-inertial measurement unit (MIMU) using a functional approach requiring a calibration exercise. We systematically investigated the influence of different experimental conditions that can affect precision and accuracy while estimating the CoR, such as (a) angular joint velocity, (b) distance between the MIMU and the CoR, (c) type of the joint motion implemented, (d) amplitude of the angular range of motion, (e) model of the MIMU used for data recording, (f) amplitude of additive noise on inertial signals, and (g) amplitude of the errors in the MIMU orientation. The evaluation process was articulated at three levels: assessment through experiments using a mechanical device, mathematical simulation, and an analytical propagation model of the noise. The results reveal that joint angular velocity significantly impacted CoR identification, and hence, slow joint movement should be avoided. An accurate estimation of the MIMU orientation is also fundamental for accurately subtracting the contribution owing to gravity to obtain the coordinate acceleration. The unit should be preferably attached close to the CoR, but both type and range of motion do not appear to be critical. When the proposed methodology is correctly implemented, error in the CoR estimates is expected to be <3mm (best estimates=2±0.5mm). The findings of the present study foster the need to further investigate this methodology for application in human subjects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analytical estimations of limit cycle amplitude for delay-differential equations

Directory of Open Access Journals (Sweden)

Tamás Molnár

2016-09-01

Full Text Available The amplitude of limit cycles arising from Hopf bifurcation is estimated for nonlinear delay-differential equations by means of analytical formulas. An improved analytical estimation is introduced, which allows more accurate quantitative prediction of periodic solutions than the standard approach that formulates the amplitude as a square-root function of the bifurcation parameter. The improved estimation is based on special global properties of the system: the method can be applied if the limit cycle blows up and disappears at a certain value of the bifurcation parameter. As an illustrative example, the improved analytical formula is applied to the problem of stick balancing.

FARADAY ROTATION: EFFECT OF MAGNETIC FIELD REVERSALS

International Nuclear Information System (INIS)

Melrose, D. B.

2010-01-01

The standard formula for the rotation measure (RM), which determines the position angle, ψ = RMλ 2 , due to Faraday rotation, includes contributions only from the portions of the ray path where the natural modes of the plasma are circularly polarized. In small regions of the ray path where the projection of the magnetic field on the ray path reverses sign (called QT regions) the modes are nearly linearly polarized. The neglect of QT regions in estimating RM is not well justified at frequencies below a transition frequency where mode coupling changes from strong to weak. By integrating the polarization transfer equation across a QT region in the latter limit, I estimate the additional contribution Δψ needed to correct this omission. In contrast with a result proposed by Broderick and Blandford, Δψ is small and probably unobservable. I identify a new source of circular polarization, due to mode coupling in an asymmetric QT region. I also identify a new circular-polarization-dependent correction to the dispersion measure at low frequencies.

FARADAY ROTATION: EFFECT OF MAGNETIC FIELD REVERSALS

Energy Technology Data Exchange (ETDEWEB)

Melrose, D B [SIfA, School of Physics, University of Sydney, NSW 2006 (Australia)

2010-12-20

The standard formula for the rotation measure (RM), which determines the position angle, {psi} = RM{lambda}{sup 2}, due to Faraday rotation, includes contributions only from the portions of the ray path where the natural modes of the plasma are circularly polarized. In small regions of the ray path where the projection of the magnetic field on the ray path reverses sign (called QT regions) the modes are nearly linearly polarized. The neglect of QT regions in estimating RM is not well justified at frequencies below a transition frequency where mode coupling changes from strong to weak. By integrating the polarization transfer equation across a QT region in the latter limit, I estimate the additional contribution {Delta}{psi} needed to correct this omission. In contrast with a result proposed by Broderick and Blandford, {Delta}{psi} is small and probably unobservable. I identify a new source of circular polarization, due to mode coupling in an asymmetric QT region. I also identify a new circular-polarization-dependent correction to the dispersion measure at low frequencies.

An estimation of tritium inventory limits for the E-Area vaults

International Nuclear Information System (INIS)

Yu, A.D.; Cook, J.R.

1991-01-01

At the request of Waste Management, Interim Waste Technology has conducted a modeling study to estimate the tritium inventory limits for the E-Area vaults. These inventory limits are based on the groundwater impact of the planned waste disposal. The tritium inventory limit for an Intermediate Level Tritium Vault (ILTV) is estimated to be 400,000 Curies with a 100 year storage period. During this period, it is assumed that the ILTV will be vented, any leachate will be extracted, and its performance will be carefully monitored. The tritium inventory limits for a Low Activity Waste Vault (LAWV) and an Intermediate Level Non-Tritium Vault (ILNTV) are estimated to be 15,000 and 11,000 Curies, respectively. Venting and leachate extraction were not assumed necessary. These operational alternatives would further enhance the performance of these vaults. These limits are significantly higher than the forecasted maximum tritium inventories for the vaults. Details of the modeling study are described in the attached report

Unlocking the talus by eversion limits medial ankle injury risk during external rotation.

Science.gov (United States)

Button, Keith D; Wei, Feng; Haut, Roger C

2015-10-15

Eversion prior to excessive external foot rotation has been shown to predispose the anterior tibiofibular ligament (ATiFL) to failure, yet protect the anterior deltoid ligament (ADL) from failure despite high levels of foot rotation. The purpose of the current study was to measure the rotations of both the subtalar and talocrural joints during foot external rotation at sub-failure levels in either a neutral or a pre-everted position as a first step towards understanding the mechanisms of injury in previous studies. Fourteen (seven pairs) cadaver lower extremities were externally rotated 20° in either a pre-everted or neutral configuration, without producing injury. Motion capture was performed to track the tibia, talus, and calcaneus motions, and a joint coordinate system was used to analyze motions of the two joints. While talocrural joint rotation was greater in the neutral ankle (13.3±2.0° versus 10.5±2.7°, p=0.006), subtalar joint rotation was greater in the pre-everted ankle (2.4±1.9° versus 1.1±1.0°, p=0.014). Overall, the talocrural joint rotated more than the subtalar joint (11.9±2.8° versus 1.8±1.6°, p<0.001). It was proposed that the calcaneus and talus 'lock' in a neutral position, but 'unlock' when the ankle is everted prior to rotation. This locking/unlocking mechanism could be responsible for an increased subtalar rotation, but decreased talocrural rotation when the ankle is pre-everted, protecting the ADL from failure. This study may provide information valuable to the study of external rotation kinematics and injury risk. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rotation-limited growth of three-dimensional body-centered-cubic crystals.

Science.gov (United States)

Tarp, Jens M; Mathiesen, Joachim

2015-07-01

According to classical grain growth laws, grain growth is driven by the minimization of surface energy and will continue until a single grain prevails. These laws do not take into account the lattice anisotropy and the details of the microscopic rearrangement of mass between grains. Here we consider coarsening of body-centered-cubic polycrystalline materials in three dimensions using the phase field crystal model. We observe, as a function of the quenching depth, a crossover between a state where grain rotation halts and the growth stagnates and a state where grains coarsen rapidly by coalescence through rotation and alignment of the lattices of neighboring grains. We show that the grain rotation per volume change of a grain follows a power law with an exponent of -1.25. The scaling exponent is consistent with theoretical considerations based on the conservation of dislocations.

Rotational Energy as Mass in H3 + and Lower Limits on the Atomic Masses of D and 3He

Science.gov (United States)

Smith, J. A.; Hamzeloui, S.; Fink, D. J.; Myers, E. G.

2018-04-01

We have made precise measurements of the cyclotron frequency ratios H3 +/HD+ and H3 +/ 3He+ and observe that different H3+ ions result in different cyclotron frequency ratios. We interpret these differences as due to the molecular rotational energy of H3 + changing its inertial mass. We also confirm that certain high J , K rotational levels of H3+ have mean lifetimes exceeding several weeks. From measurements with the lightest H3+ ion we obtain lower limits on the atomic masses of deuterium and helium-3 with respect to the proton.

Rotational Energy as Mass in H_{3}^{+} and Lower Limits on the Atomic Masses of D and ^{3}He.

Science.gov (United States)

Smith, J A; Hamzeloui, S; Fink, D J; Myers, E G

2018-04-06

We have made precise measurements of the cyclotron frequency ratios H_{3}^{+}/HD^{+} and H_{3}^{+}/^{3}He^{+} and observe that different H_{3}^{+} ions result in different cyclotron frequency ratios. We interpret these differences as due to the molecular rotational energy of H_{3}^{+} changing its inertial mass. We also confirm that certain high J, K rotational levels of H_{3}^{+} have mean lifetimes exceeding several weeks. From measurements with the lightest H_{3}^{+} ion we obtain lower limits on the atomic masses of deuterium and helium-3 with respect to the proton.

Spatiotemporal noise covariance estimation from limited empirical magnetoencephalographic data

International Nuclear Information System (INIS)

Jun, Sung C; Plis, Sergey M; Ranken, Doug M; Schmidt, David M

2006-01-01

The performance of parametric magnetoencephalography (MEG) and electroencephalography (EEG) source localization approaches can be degraded by the use of poor background noise covariance estimates. In general, estimation of the noise covariance for spatiotemporal analysis is difficult mainly due to the limited noise information available. Furthermore, its estimation requires a large amount of storage and a one-time but very large (and sometimes intractable) calculation or its inverse. To overcome these difficulties, noise covariance models consisting of one pair or a sum of multi-pairs of Kronecker products of spatial covariance and temporal covariance have been proposed. However, these approaches cannot be applied when the noise information is very limited, i.e., the amount of noise information is less than the degrees of freedom of the noise covariance models. A common example of this is when only averaged noise data are available for a limited prestimulus region (typically at most a few hundred milliseconds duration). For such cases, a diagonal spatiotemporal noise covariance model consisting of sensor variances with no spatial or temporal correlation has been the common choice for spatiotemporal analysis. In this work, we propose a different noise covariance model which consists of diagonal spatial noise covariance and Toeplitz temporal noise covariance. It can easily be estimated from limited noise information, and no time-consuming optimization and data-processing are required. Thus, it can be used as an alternative choice when one-pair or multi-pair noise covariance models cannot be estimated due to lack of noise information. To verify its capability we used Bayesian inference dipole analysis and a number of simulated and empirical datasets. We compared this covariance model with other existing covariance models such as conventional diagonal covariance, one-pair and multi-pair noise covariance models, when noise information is sufficient to estimate them. We

Examining cotton in rotation with rice and cotton in rotation with other crops using natural experiment

Science.gov (United States)

Sun, Ling; Zhu, Zesheng

2017-08-01

This paper is to show the ability of remote sensing image analysis combined with statistical analysis to characterize the environmental risk assessment of cotton in rotation with rice and cotton in rotation with other crops in two ways: (1) description of rotation period of cotton in rotation with rice and cotton in rotation with other crops by the observational study or natural experiment; (2) analysis of rotation period calculation of cotton in rotation with rice and cotton in rotation with other crops. Natural experimental results show that this new method is very promising for determining crop rotation period for estimating regional averages of environmental risk. When it is applied to determining crop rotation period, two requested remote sensing images of regional crop are required at least.

A self-calibration method in single-axis rotational inertial navigation system with rotating mechanism

Science.gov (United States)

Chen, Yuanpei; Wang, Lingcao; Li, Kui

2017-10-01

Rotary inertial navigation modulation mechanism can greatly improve the inertial navigation system (INS) accuracy through the rotation. Based on the single-axis rotational inertial navigation system (RINS), a self-calibration method is put forward. The whole system is applied with the rotation modulation technique so that whole inertial measurement unit (IMU) of system can rotate around the motor shaft without any external input. In the process of modulation, some important errors can be decoupled. Coupled with the initial position information and attitude information of the system as the reference, the velocity errors and attitude errors in the rotation are used as measurement to perform Kalman filtering to estimate part of important errors of the system after which the errors can be compensated into the system. The simulation results show that the method can complete the self-calibration of the single-axis RINS in 15 minutes and estimate gyro drifts of three-axis, the installation error angle of the IMU and the scale factor error of the gyro on z-axis. The calibration accuracy of optic gyro drifts could be about 0.003°/h (1σ) as well as the scale factor error could be about 1 parts per million (1σ). The errors estimate reaches the system requirements which can effectively improve the longtime navigation accuracy of the vehicle or the boat.

Estimating the implicit component of visuomotor rotation learning by constraining movement preparation time.

Science.gov (United States)

Leow, Li-Ann; Gunn, Reece; Marinovic, Welber; Carroll, Timothy J

2017-08-01

When sensory feedback is perturbed, accurate movement is restored by a combination of implicit processes and deliberate reaiming to strategically compensate for errors. Here, we directly compare two methods used previously to dissociate implicit from explicit learning on a trial-by-trial basis: 1 ) asking participants to report the direction that they aim their movements, and contrasting this with the directions of the target and the movement that they actually produce, and 2 ) manipulating movement preparation time. By instructing participants to reaim without a sensory perturbation, we show that reaiming is possible even with the shortest possible preparation times, particularly when targets are narrowly distributed. Nonetheless, reaiming is effortful and comes at the cost of increased variability, so we tested whether constraining preparation time is sufficient to suppress strategic reaiming during adaptation to visuomotor rotation with a broad target distribution. The rate and extent of error reduction under preparation time constraints were similar to estimates of implicit learning obtained from self-report without time pressure, suggesting that participants chose not to apply a reaiming strategy to correct visual errors under time pressure. Surprisingly, participants who reported aiming directions showed less implicit learning according to an alternative measure, obtained during trials performed without visual feedback. This suggests that the process of reporting can affect the extent or persistence of implicit learning. The data extend existing evidence that restricting preparation time can suppress explicit reaiming and provide an estimate of implicit visuomotor rotation learning that does not require participants to report their aiming directions. NEW & NOTEWORTHY During sensorimotor adaptation, implicit error-driven learning can be isolated from explicit strategy-driven reaiming by subtracting self-reported aiming directions from movement directions, or

Estimation of the adiabatic energy limit versus beta in Baseball II

International Nuclear Information System (INIS)

Foote, J.H.

1976-01-01

Several estimates of the adiabatic energy limit versus beta in Baseball II are summarized, and the calculational methods used to obtain them are described. Some estimates are based on analytic expressions; for others, particle orbits are calculated, magnetic-moment jumps are inspected, and adiabatic limits then derived. The results are sensitive to the assumed variation of the combined vacuum-plus-plasma magnetic field. The calculated adiabatic energy limit falls rapidly with beta, even for a gradual magnetic-field variation. If we assume a sharp depression in the axial profile of the combined magnetic field for a finite-beta plasma, the adiabatic limit can be further markedly reduced

Fracture mechanics approach to estimate rail wear limits

Science.gov (United States)

2009-10-01

This paper describes a systematic methodology to estimate allowable limits for rail head wear in terms of vertical head-height loss, gage-face side wear, and/or the combination of the two. This methodology is based on the principles of engineering fr...

Revision of risk estimates and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

It has been apparent for some time that our estimates of the risks associated with exposure to ionizing radiation must be increased above those values reported by UNSCEAR in 1977 an dused by ICRP to form their present recommendations. NRPB foresaw some of these changes and introduced interim advice within the UK to restrict exposures of wordkers and members of the public to levels below the existing limits. Since that advice was given, UNSCEAR has produced a 1988 report reviewing human data to provide new estimates of risks associated with exposure at high doses and high doserates. These risk figures are up to 4 times higher than when UNSCEAR reported in 1977. In this paper, the reasons for the changes in the estimates of risk will be described and the current NRPB guidelines for risk factors for protection purposes will be presented. The implications of these new risk factors for the setting of dose limits will then be discussed. (Author). 10 refs.; 2 tabs

Superconducting rotating machines

International Nuclear Information System (INIS)

Smith, J.L. Jr.; Kirtley, J.L. Jr.; Thullen, P.

1975-01-01

The opportunities and limitations of the applications of superconductors in rotating electric machines are given. The relevant properties of superconductors and the fundamental requirements for rotating electric machines are discussed. The current state-of-the-art of superconducting machines is reviewed. Key problems, future developments and the long range potential of superconducting machines are assessed

A non-parametric framework for estimating threshold limit values

Directory of Open Access Journals (Sweden)

Ulm Kurt

2005-11-01

Full Text Available Abstract Background To estimate a threshold limit value for a compound known to have harmful health effects, an 'elbow' threshold model is usually applied. We are interested on non-parametric flexible alternatives. Methods We describe how a step function model fitted by isotonic regression can be used to estimate threshold limit values. This method returns a set of candidate locations, and we discuss two algorithms to select the threshold among them: the reduced isotonic regression and an algorithm considering the closed family of hypotheses. We assess the performance of these two alternative approaches under different scenarios in a simulation study. We illustrate the framework by analysing the data from a study conducted by the German Research Foundation aiming to set a threshold limit value in the exposure to total dust at workplace, as a causal agent for developing chronic bronchitis. Results In the paper we demonstrate the use and the properties of the proposed methodology along with the results from an application. The method appears to detect the threshold with satisfactory success. However, its performance can be compromised by the low power to reject the constant risk assumption when the true dose-response relationship is weak. Conclusion The estimation of thresholds based on isotonic framework is conceptually simple and sufficiently powerful. Given that in threshold value estimation context there is not a gold standard method, the proposed model provides a useful non-parametric alternative to the standard approaches and can corroborate or challenge their findings.

Exotic rotational correlations in quantum geometry

Energy Technology Data Exchange (ETDEWEB)

Hogan, Craig

2017-05-01

It is argued by extrapolation of general relativity and quantum mechanics that a classical inertial frame corresponds to a statistically defined observable that rotationally fluctuates due to Planck scale indeterminacy. Physical effects of exotic nonlocal rotational correlations on large scale field states are estimated. Their entanglement with the strong interaction vacuum is estimated to produce a universal, statistical centrifugal acceleration that resembles the observed cosmological constant.

Observations of Near-Field Rotational Motions from Oklahoma Seismicity using Applied Technology Associate Sensors

Science.gov (United States)

Ringler, A. T.; Anthony, R. E.; Holland, A. A.; Wilson, D. C.

2017-12-01

Characterizing rotational motions from moderate-sized earthquakes in the near-field has the potential to improve earthquake engineering and seismic gradiometry by better characterizing the rotational component of the seismic wavefield, but has remained challenging due to the limited development of portable, low-noise rotational sensors. Here, we test Applied Technology Associate (ATA) Proto-Seismic Magnetohydrodynamic (SMHD) three-component rotational rate sensors at Albuquerque Seismological Laboratory (ASL) for self-noise and sensitivity before deploying them at U.S. Geological Survey (USGS) temporary aftershock station OK38 in Waynoka, Oklahoma. The sensors have low self-noise levels below 2 Hz, making them ideal to record local rotations. From April 11, 2017 to June 6, 2017 we recorded the translational and rotational motions of over 155 earthquakes of ML≥2.0 within 2 degrees of the station. Using the recorded events we compare Peak Ground Velocity (PGV) with Peak Ground Rotation Rate (PG). For example, we measured a maximal PG of 0.00211 radians/s and 0.00186 radians/s for the horizontal components of the two rotational sensors during the Mwr=4.2 event on May 13, 2017 which was 0.5 km from that station. Similarly, our PG for the vertical rotational components were 0.00112 radians/s and 0.00085 radians/s. We also measured Peak Ground Rotations (PGω) as a function of seismic moment, as well as mean vertical Power Spectral Density (PSD) with mean horizontal PSD power levels. We compute apparent phase velocity directly from the rotational data, which may have may improve estimates of local site effects. Finally, by comparing various rotational and translational components we look at potential implications for estimating local event source parameters, which may help in identifying phenomena such as repeating earthquakes by using differences in the rotational components correlation.

ASYMPTOTIC COMPARISONS OF U-STATISTICS, V-STATISTICS AND LIMITS OF BAYES ESTIMATES BY DEFICIENCIES

OpenAIRE

Toshifumi, Nomachi; Hajime, Yamato; Graduate School of Science and Engineering, Kagoshima University:Miyakonojo College of Technology; Faculty of Science, Kagoshima University

2001-01-01

As estimators of estimable parameters, we consider three statistics which are U-statistic, V-statistic and limit of Bayes estimate. This limit of Bayes estimate, called LB-statistic in this paper, is obtained from Bayes estimate of estimable parameter based on Dirichlet process, by letting its parameter tend to zero. For the estimable parameter with non-degenerate kernel, the asymptotic relative efficiencies of LB-statistic with respect to U-statistic and V-statistic and that of V-statistic w...

Limited diagnostic accuracy of magnetic resonance imaging and clinical tests for detecting partial-thickness tears of the rotator cuff.

Science.gov (United States)

Brockmeyer, Matthias; Schmitt, Cornelia; Haupert, Alexander; Kohn, Dieter; Lorbach, Olaf

2017-12-01

The reliable diagnosis of partial-thickness tears of the rotator cuff is still elusive in clinical practise. Therefore, the purpose of the study was to determine the diagnostic accuracy of MR imaging and clinical tests for detecting partial-thickness tears of the rotator cuff as well as the combination of these parameters. 334 consecutive shoulder arthroscopies for rotator cuff pathologies performed during the time period between 2010 and 2012 were analyzed retrospectively for the findings of common clinical signs for rotator cuff lesions and preoperative MR imaging. These were compared with the intraoperative arthroscopic findings as "gold standard". The reports of the MR imaging were evaluated with regard to the integrity of the rotator cuff. The Ellman Classification was used to define partial-thickness tears of the rotator cuff in accordance with the arthroscopic findings. Descriptive statistics, sensitivity, specificity, positive and negative predictive value were calculated. MR imaging showed 80 partial-thickness and 70 full-thickness tears of the rotator cuff. The arthroscopic examination confirmed 64 partial-thickness tears of which 52 needed debridement or refixation of the rotator cuff. Sensitivity for MR imaging to identify partial-thickness tears was 51.6%, specificity 77.2%, positive predictive value 41.3% and negative predictive value 83.7%. For the Jobe-test, sensitivity was 64.1%, specificity 43.2%, positive predictive value 25.9% and negative predictive value 79.5%. Sensitivity for the Impingement-sign was 76.7%, specificity 46.6%, positive predictive value 30.8% and negative predictive value 86.5%. For the combination of MR imaging, Jobe-test and Impingement-sign sensitivity was 46.9%, specificity 85.4%, positive predictive value 50% and negative predictive value 83.8%. The diagnostic accuracy of MR imaging and clinical tests (Jobe-test and Impingement-sign) alone is limited for detecting partial-thickness tears of the rotator cuff. Additionally

Reliabilities of mental rotation tasks: limits to the assessment of individual differences.

Science.gov (United States)

Hirschfeld, Gerrit; Thielsch, Meinald T; Zernikow, Boris

2013-01-01

Mental rotation tasks with objects and body parts as targets are widely used in cognitive neuropsychology. Even though these tasks are well established to study between-groups differences, the reliability on an individual level is largely unknown. We present a systematic study on the internal consistency and test-retest reliability of individual differences in mental rotation tasks comparing different target types and orders of presentations. In total n = 99 participants (n = 63 for the retest) completed the mental rotation tasks with hands, feet, faces, and cars as targets. Different target types were presented in either randomly mixed blocks or blocks of homogeneous targets. Across all target types, the consistency (split-half reliability) and stability (test-retest reliabilities) were good or acceptable both for intercepts and slopes. At the level of individual targets, only intercepts showed acceptable reliabilities. Blocked presentations resulted in significantly faster and numerically more consistent and stable responses. Mental rotation tasks-especially in blocked variants-can be used to reliably assess individual differences in global processing speed. However, the assessment of the theoretically important slope parameter for individual targets requires further adaptations to mental rotation tests.

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft.

Science.gov (United States)

Giotis, D; Paschos, N K; Zampeli, F; Pappas, E; Mitsionis, G; Georgoulis, A D

2016-09-01

Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee. Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control. Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230). Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft. Level III, case-control therapeutic study. Copyright �

Fault-tolerant feature-based estimation of space debris rotational motion during active removal missions

Science.gov (United States)

Biondi, Gabriele; Mauro, Stefano; Pastorelli, Stefano; Sorli, Massimo

2018-05-01

One of the key functionalities required by an Active Debris Removal mission is the assessment of the target kinematics and inertial properties. Passive sensors, such as stereo cameras, are often included in the onboard instrumentation of a chaser spacecraft for capturing sequential photographs and for tracking features of the target surface. A plenty of methods, based on Kalman filtering, are available for the estimation of the target's state from feature positions; however, to guarantee the filter convergence, they typically require continuity of measurements and the capability of tracking a fixed set of pre-defined features of the object. These requirements clash with the actual tracking conditions: failures in feature detection often occur and the assumption of having some a-priori knowledge about the shape of the target could be restrictive in certain cases. The aim of the presented work is to propose a fault-tolerant alternative method for estimating the angular velocity and the relative magnitudes of the principal moments of inertia of the target. Raw data regarding the positions of the tracked features are processed to evaluate corrupted values of a 3-dimentional parameter which entirely describes the finite screw motion of the debris and which primarily is invariant on the particular set of considered features of the object. Missing values of the parameter are completely restored exploiting the typical periodicity of the rotational motion of an uncontrolled satellite: compressed sensing techniques, typically adopted for recovering images or for prognostic applications, are herein used in a completely original fashion for retrieving a kinematic signal that appears sparse in the frequency domain. Due to its invariance about the features, no assumptions are needed about the target's shape and continuity of the tracking. The obtained signal is useful for the indirect evaluation of an attitude signal that feeds an unscented Kalman filter for the estimation of

Real-Time Rotational Activity Detection in Atrial Fibrillation

Science.gov (United States)

Ríos-Muñoz, Gonzalo R.; Arenal, Ángel; Artés-Rodríguez, Antonio

2018-01-01

Rotational activations, or spiral waves, are one of the proposed mechanisms for atrial fibrillation (AF) maintenance. We present a system for assessing the presence of rotational activity from intracardiac electrograms (EGMs). Our system is able to operate in real-time with multi-electrode catheters of different topologies in contact with the atrial wall, and it is based on new local activation time (LAT) estimation and rotational activity detection methods. The EGM LAT estimation method is based on the identification of the highest sustained negative slope of unipolar signals. The method is implemented as a linear filter whose output is interpolated on a regular grid to match any catheter topology. Its operation is illustrated on selected signals and compared to the classical Hilbert-Transform-based phase analysis. After the estimation of the LAT on the regular grid, the detection of rotational activity in the atrium is done by a novel method based on the optical flow of the wavefront dynamics, and a rotation pattern match. The methods have been validated using in silico and real AF signals. PMID:29593566

Demonstrating Heisenberg-limited unambiguous phase estimation without adaptive measurements

International Nuclear Information System (INIS)

Higgins, B L; Wiseman, H M; Pryde, G J; Berry, D W; Bartlett, S D; Mitchell, M W

2009-01-01

We derive, and experimentally demonstrate, an interferometric scheme for unambiguous phase estimation with precision scaling at the Heisenberg limit that does not require adaptive measurements. That is, with no prior knowledge of the phase, we can obtain an estimate of the phase with a standard deviation that is only a small constant factor larger than the minimum physically allowed value. Our scheme resolves the phase ambiguity that exists when multiple passes through a phase shift, or NOON states, are used to obtain improved phase resolution. Like a recently introduced adaptive technique (Higgins et al 2007 Nature 450 393), our experiment uses multiple applications of the phase shift on single photons. By not requiring adaptive measurements, but rather using a predetermined measurement sequence, the present scheme is both conceptually simpler and significantly easier to implement. Additionally, we demonstrate a simplified adaptive scheme that also surpasses the standard quantum limit for single passes.

A Novel Strategy of Ambiguity Correction for the Improved Faraday Rotation Estimator in Linearly Full-Polarimetric SAR Data

Directory of Open Access Journals (Sweden)

Jinhui Li

2018-04-01

Full Text Available Spaceborne synthetic aperture radar (SAR missions operating at low frequencies, such as L-band or P-band, are significantly influenced by the ionosphere. As one of the serious ionosphere effects, Faraday rotation (FR is a remarkable distortion source for the polarimetric SAR (PolSAR application. Various published FR estimators along with an improved one have been introduced to solve this issue, all of which are implemented by processing a set of PolSAR real data. The improved estimator exhibits optimal robustness based on performance analysis, especially in term of the system noise. However, all published estimators, including the improved estimator, suffer from a potential FR angle (FRA ambiguity. A novel strategy of the ambiguity correction for those FR estimators is proposed and shown as a flow process, which is divided into pixel-level and image-level correction. The former is not yet recognized and thus is considered in particular. Finally, the validation experiments show a prominent performance of the proposed strategy.

A Novel Strategy of Ambiguity Correction for the Improved Faraday Rotation Estimator in Linearly Full-Polarimetric SAR Data.

Science.gov (United States)

Li, Jinhui; Ji, Yifei; Zhang, Yongsheng; Zhang, Qilei; Huang, Haifeng; Dong, Zhen

2018-04-10

Spaceborne synthetic aperture radar (SAR) missions operating at low frequencies, such as L-band or P-band, are significantly influenced by the ionosphere. As one of the serious ionosphere effects, Faraday rotation (FR) is a remarkable distortion source for the polarimetric SAR (PolSAR) application. Various published FR estimators along with an improved one have been introduced to solve this issue, all of which are implemented by processing a set of PolSAR real data. The improved estimator exhibits optimal robustness based on performance analysis, especially in term of the system noise. However, all published estimators, including the improved estimator, suffer from a potential FR angle (FRA) ambiguity. A novel strategy of the ambiguity correction for those FR estimators is proposed and shown as a flow process, which is divided into pixel-level and image-level correction. The former is not yet recognized and thus is considered in particular. Finally, the validation experiments show a prominent performance of the proposed strategy.

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.

Optimal rotation sequences for active perception

Science.gov (United States)

Nakath, David; Rachuy, Carsten; Clemens, Joachim; Schill, Kerstin

2016-05-01

One major objective of autonomous systems navigating in dynamic environments is gathering information needed for self localization, decision making, and path planning. To account for this, such systems are usually equipped with multiple types of sensors. As these sensors often have a limited field of view and a fixed orientation, the task of active perception breaks down to the problem of calculating alignment sequences which maximize the information gain regarding expected measurements. Action sequences that rotate the system according to the calculated optimal patterns then have to be generated. In this paper we present an approach for calculating these sequences for an autonomous system equipped with multiple sensors. We use a particle filter for multi- sensor fusion and state estimation. The planning task is modeled as a Markov decision process (MDP), where the system decides in each step, what actions to perform next. The optimal control policy, which provides the best action depending on the current estimated state, maximizes the expected cumulative reward. The latter is computed from the expected information gain of all sensors over time using value iteration. The algorithm is applied to a manifold representation of the joint space of rotation and time. We show the performance of the approach in a spacecraft navigation scenario where the information gain is changing over time, caused by the dynamic environment and the continuous movement of the spacecraft

The efficiency of different estimation methods of hydro-physical limits

Directory of Open Access Journals (Sweden)

Emma María Martínez

2012-12-01

Full Text Available The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP and field capacity (FC, is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and cost. The analysis evaluates both direct determination methods (pressure plate - PP and water activity meter - WAM and indirect estimation methods (pedotransfer functions - PTFs. The PTFs must be validated for the area of interest before use, but the time and cost associated with this validation are not included in the cost of analysis. Compared to the other methods, the combined use of PP and WAM to determine hydro-physical limits differs significantly in time and cost required and quality of information. For direct methods, increasing sample size significantly reduces cost and time. This paper assesses the effectiveness of combining a general analysis based on efficiency indices and more specific analyses based on the different influencing factors, which were considered separately so as not to mask potential benefits or drawbacks that are not evidenced in efficiency estimation.

Measurements of coronal Faraday rotation at 4.6 R ☉

International Nuclear Information System (INIS)

Kooi, Jason E.; Fischer, Patrick D.; Buffo, Jacob J.; Spangler, Steven R.

2014-01-01

Many competing models for the coronal heating and acceleration mechanisms of the high-speed solar wind depend on the solar magnetic field and plasma structure in the corona within heliocentric distances of 5 R ☉ . We report on sensitive Very Large Array (VLA) full-polarization observations made in 2011 August, at 5.0 and 6.1 GHz (each with a bandwidth of 128 MHz) of the radio galaxy 3C 228 through the solar corona at heliocentric distances of 4.6-5.0 R ☉ . Observations at 5.0 GHz permit measurements deeper in the corona than previous VLA observations at 1.4 and 1.7 GHz. These Faraday rotation observations provide unique information on the magnetic field in this region of the corona. The measured Faraday rotation on this day was lower than our a priori expectations, but we have successfully modeled the measurement in terms of observed properties of the corona on the day of observation. Our data on 3C 228 provide two lines of sight (separated by 46'', 33,000 km in the corona). We detected three periods during which there appeared to be a difference in the Faraday rotation measure between these two closely spaced lines of sight. These measurements (termed differential Faraday rotation) yield an estimate of 2.6-4.1 GA for coronal currents. Our data also allow us to impose upper limits on rotation measure fluctuations caused by coronal waves; the observed upper limits were 3.3 and 6.4 rad m –2 along the two lines of sight. The implications of these results for Joule heating and wave heating are briefly discussed.

Development of a fast response rotating polarimeter for a faraday rotation measurement

International Nuclear Information System (INIS)

Maeno, Masaki; Ogiwara, Norio; Ogawa, Hiroaki; Matsuda, Toshiaki

1994-03-01

This paper describes a method for using a spindle sustained with active magnetic bearing to make a rotating half waveplate frequency more fast. The time interval of the zero-cross phase measurement is 189 μsec in this experiment. The magnetic bearing is applicable to increase the rotating waveplate frequency by a factor of 2-3 compared with the conventional one. The waveplate speed as well as the deviation with respect to the stationary laser beam has no influence on the amplitude and phase shift of the rotating polarized beam signal. There is also no influence of the mirror reflections on the phase shift. The overall phase resolution is estimated to be about 0.1 degrees. (author)

Optical illusions induced by rotating medium

Science.gov (United States)

Zang, XiaoFei; Huang, PengCheng; Zhu, YiMing

2018-03-01

Different from the traditional single-function electromagnetic wave rotators (rotate the electromagnetic wavefronts), we propose that rotating medium can be extended to optical illusions such as breaking the diffraction limit and overlapping illusion. Furthermore, the homogeneous but anisotropic rotating medium is simplified by homogeneous and isotropic positive-index materials according to the effective medium theory, which is helpful for future device fabrication. Finite element simulations for the two-dimensional case are performed to demonstrate these properties.

VMAT optimization with dynamic collimator rotation.

Science.gov (United States)

Lyu, Qihui; O'Connor, Daniel; Ruan, Dan; Yu, Victoria; Nguyen, Dan; Sheng, Ke

2018-04-16

Although collimator rotation is an optimization variable that can be exploited for dosimetric advantages, existing Volumetric Modulated Arc Therapy (VMAT) optimization uses a fixed collimator angle in each arc and only rotates the collimator between arcs. In this study, we develop a novel integrated optimization method for VMAT, accounting for dynamic collimator angles during the arc motion. Direct Aperture Optimization (DAO) for Dynamic Collimator in VMAT (DC-VMAT) was achieved by adding to the existing dose fidelity objective an anisotropic total variation term for regulating the fluence smoothness, a binary variable for forming simple apertures, and a group sparsity term for controlling collimator rotation. The optimal collimator angle for each beam angle was selected using the Dijkstra's algorithm, where the node costs depend on the estimated fluence map at the current iteration and the edge costs account for the mechanical constraints of multi-leaf collimator (MLC). An alternating optimization strategy was implemented to solve the DAO and collimator angle selection (CAS). Feasibility of DC-VMAT using one full-arc with dynamic collimator rotation was tested on a phantom with two small spherical targets, a brain, a lung and a prostate cancer patient. The plan was compared against a static collimator VMAT (SC-VMAT) plan using three full arcs with 60 degrees of collimator angle separation in patient studies. With the same target coverage, DC-VMAT achieved 20.3% reduction of R50 in the phantom study, and reduced the average max and mean OAR dose by 4.49% and 2.53% of the prescription dose in patient studies, as compared with SC-VMAT. The collimator rotation co-ordinated with the gantry rotation in DC-VMAT plans for deliverability. There were 13 beam angles in the single-arc DC-VMAT plan in patient studies that requires slower gantry rotation to accommodate multiple collimator angles. The novel DC-VMAT approach utilizes the dynamic collimator rotation during arc

Wave-Driven Rotation In Centrifugal Mirrors

International Nuclear Information System (INIS)

Fetterman, Abraham J.; Fisch, Nathaniel J.

2011-01-01

Centrifugal mirrors use supersonic rotation to provide axial confinement and enhanced stability. Usually the rotation is produced using electrodes, but these electrodes have limited the rotation to the Alfven critical ionization velocity, which is too slow to be useful for fusion. Instead, the rotation could be produced using radio frequency waves. A fixed azimuthal ripple is a simple and efficient wave that could produce rotation by harnessing alpha particle energy. This is an extension of the alpha channeling effect. The alpha particle power and efficiency in a simulated devices is sufficient to produce rotation without external energy input. By eliminating the need for electrodes, this opens new opportunities for centrifugal traps.

Current estimates of radiation risks and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

The publication of the 1988 report of UNSCEAR represents a major step forward in that there is an international consensus on the estimation of risk from exposure to ionising radiation. The estimates of fatal cancers in the UNSCEAR report are up to 4 times the values in the 1977 review. This paper will describe the reasons for the increase, the remaining uncertainties and the implications for dose limits in occupational and public exposure. (author)

Fundamental limits of radio interferometers: calibration and source parameter estimation

OpenAIRE

Trott, Cathryn M.; Wayth, Randall B.; Tingay, Steven J.

2012-01-01

We use information theory to derive fundamental limits on the capacity to calibrate next-generation radio interferometers, and measure parameters of point sources for instrument calibration, point source subtraction, and data deconvolution. We demonstrate the implications of these fundamental limits, with particular reference to estimation of the 21cm Epoch of Reionization power spectrum with next-generation low-frequency instruments (e.g., the Murchison Widefield Array -- MWA, Precision Arra...

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

Multi-vortex crystal lattices in Bose-Einstein condensates with a rotating trap.

Science.gov (United States)

Xie, Shuangquan; Kevrekidis, Panayotis G; Kolokolnikov, Theodore

2018-05-01

We consider vortex dynamics in the context of Bose-Einstein condensates (BECs) with a rotating trap, with or without anisotropy. Starting with the Gross-Pitaevskii (GP) partial differential equation (PDE), we derive a novel reduced system of ordinary differential equations (ODEs) that describes stable configurations of multiple co-rotating vortices (vortex crystals). This description is found to be quite accurate quantitatively especially in the case of multiple vortices. In the limit of many vortices, BECs are known to form vortex crystal structures, whereby vortices tend to arrange themselves in a hexagonal-like spatial configuration. Using our asymptotic reduction, we derive the effective vortex crystal density and its radius. We also obtain an asymptotic estimate for the maximum number of vortices as a function of rotation rate. We extend considerations to the anisotropic trap case, confirming that a pair of vortices lying on the long (short) axis is linearly stable (unstable), corroborating the ODE reduction results with full PDE simulations. We then further investigate the many-vortex limit in the case of strong anisotropic potential. In this limit, the vortices tend to align themselves along the long axis, and we compute the effective one-dimensional vortex density, as well as the maximum admissible number of vortices. Detailed numerical simulations of the GP equation are used to confirm our analytical predictions.

Application of ring lasers to determine the directions to the poles of Earth's rotation

International Nuclear Information System (INIS)

Golyaev, Yu D; Kolbas, Yu Yu

2012-01-01

Application of a ring laser to determine the directions to the poles of Earth's rotation is considered. The maximum accuracy of determining the directions is calculated, physical and technical mechanisms that limit the accuracy are analysed, and the instrumental errors are estimated by the example of ring He — Ne lasers with Zeeman biasing. (laser applications and other topics in quantum electronics)

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

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

Calibrated Tully-Fisher relations for improved estimates of disc rotation velocities

Science.gov (United States)

Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.; Lackner, C. N.

2011-11-01

In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity Vrot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of Vrot applicable to large galaxy samples from imaging surveys. To achieve this goal, we have constructed a sample of 189 disc galaxies at redshifts z < 0.1 with long-slit Hα spectroscopy from Pizagno et al. and new observations. By construction, this sample is a fair subsample of a large, well-defined parent disc sample of ˜170 000 galaxies selected from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). The optimal photometric estimator of Vrot we find is stellar mass M★ from Bell et al., based on the linear combination of a luminosity and a colour. Assuming a Kroupa initial mass function (IMF), we find: log [V80/(km s-1)] = (2.142 ± 0.004) + (0.278 ± 0.010)[log (M★/M⊙) - 10.10], where V80 is the rotation velocity measured at the radius R80 containing 80 per cent of the i-band galaxy light. This relation has an intrinsic Gaussian scatter ? dex and a measured scatter σmeas= 0.056 dex in log V80. For a fixed IMF, we find that the dynamical-to-stellar mass ratios within R80, (Mdyn/M★)(R80), decrease from approximately 10 to 3, as stellar mass increases from M★≈ 109 to 1011 M⊙. At a fixed stellar mass, (Mdyn/M★)(R80) increases with disc size, so that it correlates more tightly with stellar surface density than with stellar mass or disc size alone. We interpret the observed variation in (Mdyn/M★)(R80) with disc size as a reflection of the fact that disc size dictates the radius at which Mdyn/M★ is measured, and consequently, the fraction of the dark matter 'seen' by the gas at that radius. For the lowest M★ galaxies, we find a positive correlation between TFR residuals and disc sizes, indicating that the total density profile is dominated by dark matter on these scales. For the

Friction, Free Axes of Rotation and Entropy

Directory of Open Access Journals (Sweden)

Alexander Kazachkov

2017-03-01

Full Text Available Friction forces acting on rotators may promote their alignment and therefore eliminate degrees of freedom in their movement. The alignment of rotators by friction force was shown by experiments performed with different spinners, demonstrating how friction generates negentropy in a system of rotators. A gas of rigid rotators influenced by friction force is considered. The orientational negentropy generated by a friction force was estimated with the Sackur-Tetrode equation. The minimal change in total entropy of a system of rotators, corresponding to their eventual alignment, decreases with temperature. The reported effect may be of primary importance for the phase equilibrium and motion of ubiquitous colloidal and granular systems.

Enstrophy-based proper orthogonal decomposition of flow past rotating cylinder at super-critical rotating rate

Science.gov (United States)

Sengupta, Tapan K.; Gullapalli, Atchyut

2016-11-01

Spinning cylinder rotating about its axis experiences a transverse force/lift, an account of this basic aerodynamic phenomenon is known as the Robins-Magnus effect in text books. Prandtl studied this flow by an inviscid irrotational model and postulated an upper limit of the lift experienced by the cylinder for a critical rotation rate. This non-dimensional rate is the ratio of oncoming free stream speed and the surface speed due to rotation. Prandtl predicted a maximum lift coefficient as CLmax = 4π for the critical rotation rate of two. In recent times, evidences show the violation of this upper limit, as in the experiments of Tokumaru and Dimotakis ["The lift of a cylinder executing rotary motions in a uniform flow," J. Fluid Mech. 255, 1-10 (1993)] and in the computed solution in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)]. In the latter reference, this was explained as the temporal instability affecting the flow at higher Reynolds number and rotation rates (>2). Here, we analyze the flow past a rotating cylinder at a super-critical rotation rate (=2.5) by the enstrophy-based proper orthogonal decomposition (POD) of direct simulation results. POD identifies the most energetic modes and helps flow field reconstruction by reduced number of modes. One of the motivations for the present study is to explain the shedding of puffs of vortices at low Reynolds number (Re = 60), for the high rotation rate, due to an instability originating in the vicinity of the cylinder, using the computed Navier-Stokes equation (NSE) from t = 0 to t = 300 following an impulsive start. This instability is also explained through the disturbance mechanical energy equation, which has been established earlier in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)].

The Societal and Economic Value of Rotator Cuff Repair

Science.gov (United States)

Mather, Richard C.; Koenig, Lane; Acevedo, Daniel; Dall, Timothy M.; Gallo, Paul; Romeo, Anthony; Tongue, John; Williams, Gerald

2013-01-01

Background: Although rotator cuff disease is a common musculoskeletal problem in the United States, the impact of this condition on earnings, missed workdays, and disability payments is largely unknown. This study examines the value of surgical treatment for full-thickness rotator cuff tears from a societal perspective. Methods: A Markov decision model was constructed to estimate lifetime direct and indirect costs associated with surgical and continued nonoperative treatment for symptomatic full-thickness rotator cuff tears. All patients were assumed to have been unresponsive to one six-week trial of nonoperative treatment prior to entering the model. Model assumptions were obtained from the literature and data analysis. We obtained estimates of indirect costs using national survey data and patient-reported outcomes. Four indirect costs were modeled: probability of employment, household income, missed workdays, and disability payments. Direct cost estimates were based on average Medicare reimbursements with adjustments to an all-payer population. Effectiveness was expressed in quality-adjusted life years (QALYs). Results: The age-weighted mean total societal savings from rotator cuff repair compared with nonoperative treatment was $13,771 over a patient’s lifetime. Savings ranged from $77,662 for patients who are thirty to thirty-nine years old to a net cost to society of $11,997 for those who are seventy to seventy-nine years old. In addition, surgical treatment results in an average improvement of 0.62 QALY. Societal savings were highly sensitive to age, with savings being positive at the age of sixty-one years and younger. The estimated lifetime societal savings of the approximately 250,000 rotator cuff repairs performed in the U.S. each year was $3.44 billion. Conclusions: Rotator cuff repair for full-thickness tears produces net societal cost savings for patients under the age of sixty-one years and greater QALYs for all patients. Rotator cuff repair is cost

Plasma residual poloidal rotation in TCABR tokamak

International Nuclear Information System (INIS)

Severo, J.H.F.; Nascimento, I.C.; Tsypin, V.S.; Galvao, R.M.O.

2003-01-01

This paper reports the first measurement of the radial profiles of plasma poloidal and toroidal rotation performed on the TCABR tokamak for a collisional plasma (Pfirsch-Schluter regime), using Doppler shift of carbon spectral lines, measured with a high precision optical spectrometer. The results for poloidal rotation show a maximum velocity of (4.5±1.0)·10 3 m/s at r ∼ 2/3a, (a - limiter radius), in the direction of the diamagnetic electron drift. Within the error limits, reasonable agreement is obtained with calculations using the neoclassical theory for a collisional plasma, except near the plasma edge, as expected. For toroidal rotation, the radial profile shows that the velocity decreases from a counter-current value of (20 ± 1) · 10 3 m/s for the plasma core to a co-current value of (2.0 ± 1.0) · 10 3 m/s near the limiter. An agreement within a factor 2, for the plasma core rotation, is obtained with calculations using the model proposed by Kim, Diamond and Groebner. (author)

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.

Applications of seismic spatial wavefield gradient and rotation data in exploration seismology

Science.gov (United States)

Schmelzbach, C.; Van Renterghem, C.; Sollberger, D.; Häusler, M.; Robertsson, J. O. A.

2017-12-01

Seismic spatial wavefield gradient and rotation data have the potential to open up new ways to address long-standing problems in land-seismic exploration such as identifying and separating P-, S-, and surface waves. Gradient-based acquisition and processing techniques could enable replacing large arrays of densely spaced receivers by sparse spatially-compact receiver layouts or even one single multicomponent station with dedicated instruments (e.g., rotational seismometers). Such approaches to maximize the information content of single-station recordings are also of significant interest for seismic measurements at sites with limited access such as boreholes, the sea bottom, and extraterrestrial seismology. Arrays of conventional three-component (3C) geophones enable measuring not only the particle velocity in three dimensions but also estimating their spatial gradients. Because the free-surface condition allows to express vertical derivatives in terms of horizontal derivatives, the full gradient tensor and, hence, curl and divergence of the wavefield can be computed. In total, three particle velocity components, three rotational components, and divergence, result seven-component (7C) seismic data. Combined particle velocity and gradient data can be used to isolate the incident P- or S-waves at the land surface or the sea bottom using filtering techniques based on the elastodynamic representation theorem. Alternatively, as only S-waves exhibit rotational motion, rotational measurements can directly be used to identify S-waves. We discuss the derivations of the gradient-based filters as well as their application to synthetic and field data, demonstrating that rotational data can be of particular interest to S-wave reflection and P-to-S-wave conversion imaging. The concept of array-derived gradient estimation can be extended to source arrays as well. Therefore, source arrays allow us to emulate rotational (curl) and dilatational (divergence) sources. Combined with 7C

Sensorless interior permanent magnet synchronous motor control with rotational inertia adjustment

Directory of Open Access Journals (Sweden)

Yongle Mao

2016-12-01

Full Text Available Mechanical model is generally required in high dynamic sensorless motor control schemes for zero phase lag estimation of rotor position and speed. However, the rotational inertia uncertainty will cause dynamic estimation errors, eventually resulting in performance deterioration of the sensorless control system. Therefore, this article proposes a high dynamic performance sensorless control strategy with online adjustment of the rotational inertia. Based on a synthetic back electromotive force model, the voltage equation of interior permanent magnet synchronous motor is transformed to that of an equivalent non-salient permanent magnet synchronous motor. Then, an extended nonlinear observer is designed for interior permanent magnet synchronous motor in the stator-fixed coordinate frame, with rotor position, speed and load torque simultaneously estimated. The effect of inaccurate rotational inertia on the estimation of rotor position and speed is investigated, and a novel rotational inertia adjustment approach that employs the gradient descent algorithm is proposed to suppress the dynamic estimation errors. The effectiveness of the proposed control strategy is demonstrated by experimental tests.

Advances in Rotational Seismic Measurements

Energy Technology Data Exchange (ETDEWEB)

Pierson, Robert [Applied Technology Associates, Albuquerque, NM (United States); Laughlin, Darren [Applied Technology Associates, Albuquerque, NM (United States); Brune, Robert [Applied Technology Associates, Albuquerque, NM (United States)

2016-10-19

Rotational motion is increasingly understood to be a significant part of seismic wave motion. Rotations can be important in earthquake strong motion and in Induced Seismicity Monitoring. Rotational seismic data can also enable shear selectivity and improve wavefield sampling for vertical geophones in 3D surveys, among other applications. However, sensor technology has been a limiting factor to date. The US Department of Energy (DOE) and Applied Technology Associates (ATA) are funding a multi-year project that is now entering Phase 2 to develop and deploy a new generation of rotational sensors for validation of rotational seismic applications. Initial focus is on induced seismicity monitoring, particularly for Enhanced Geothermal Systems (EGS) with fracturing. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, improved noise floors, robustness, and repeatability. This paper presents a summary of Phase 1 results and Phase 2 status.

DOA and Polarization Estimation Using an Electromagnetic Vector Sensor Uniform Circular Array Based on the ESPRIT Algorithm.

Science.gov (United States)

Wu, Na; Qu, Zhiyu; Si, Weijian; Jiao, Shuhong

2016-12-13

In array signal processing systems, the direction of arrival (DOA) and polarization of signals based on uniform linear or rectangular sensor arrays are generally obtained by rotational invariance techniques (ESPRIT). However, since the ESPRIT algorithm relies on the rotational invariant structure of the received data, it cannot be applied to electromagnetic vector sensor arrays (EVSAs) featuring uniform circular patterns. To overcome this limitation, a fourth-order cumulant-based ESPRIT algorithm is proposed in this paper, for joint estimation of DOA and polarization based on a uniform circular EVSA. The proposed algorithm utilizes the fourth-order cumulant to obtain a virtual extended array of a uniform circular EVSA, from which the pairs of rotation invariant sub-arrays are obtained. The ESPRIT algorithm and parameter pair matching are then utilized to estimate the DOA and polarization of the incident signals. The closed-form parameter estimation algorithm can effectively reduce the computational complexity of the joint estimation, which has been demonstrated by numerical simulations.

Estimation of reactive power sources dynamic limits for Volt / VAr control

International Nuclear Information System (INIS)

Orozco Alvarado, Juan Jose

2013-01-01

A generic model of capacity curves is obtained from the theoretical capacity curves of the distribution generators and reactive compensation elements. The obtained generic model is structured in a simplified method of points, taking eight strategic points of two detailed curves of a generator and through a series of interpolations, achieving the estimation of limits of capacity of delivery / consumption of the generator. The theory of electric generation elements and reactive power compensation is reviewed. The curves of capacity 'Reactive Power / Active Power' are achieved for different values of tension: from wind generators with complete converter and doubly fed, photovoltaic generators with inverter and synchronous generators. The 'Reactive Power / Line Tension' capacity curves are acquired from static var compensators (SVC). The generic limits of generators and SVC are estimated from the capacity curves [es

From the RSNA refresher courses: US of the rotator cuff: pitfalls, limitations, and artifacts.

NARCIS (Netherlands)

Rutten, M.J.C.M.; Jager, G.J.; Blickman, J.G.

2006-01-01

High-resolution ultrasonography (US) has gained increasing popularity as a diagnostic tool for assessment of the soft tissues in shoulder impingement syndrome. US is a powerful and accurate method for diagnosis of rotator cuff tears and other rotator cuff abnormalities, provided the examiner has a

From the RSNA refresher courses - US of the rotator cuff : Pitfalls, limitations, and artifacts

NARCIS (Netherlands)

Rutten, Matthieu J. C. M.; Jager, Gerrit J.; Blickman, Johan G.

2006-01-01

High-resolution ultrasonography (US) has gained increasing popularity as a diagnostic tool for assessment of the soft tissues in shoulder impingement syndrome. US is a powerful and accurate method for diagnosis of rotator cuff tears and other rotator cuff abnormalities, provided the examiner has a

Proteomics perspectives in rotator cuff research

DEFF Research Database (Denmark)

Sejersen, Maria Hee Jung; Frost, Poul; Hansen, Torben Bæk

2015-01-01

Background Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other...... studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue. Results We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy......, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although...

Differential Rotation in Sun-like Stars from Surface Variability and Asteroseismology

Science.gov (United States)

Nielsen, Martin Bo

2017-03-01

The Sun and other stars are known to oscillate. Through the study of small perturbations to the frequencies of these oscillations the rotation of the deep interior can be inferred. However, thus far the internal rotation of other Sun-like stars is unknown. The NASA Kepler mission has observed a multitude of Sun-like stars over a period of four years. This has provided high-quality photometric data that can be used to study the rotation of stars with two different techniques: asteroseismology and surface activity. Asteroseismology provides a means of measuring rotation in the stellar interior, while photometric variability from magnetically active regions are sensitive to rotation at the stellar surface. The combination of these two methods can be used to constrain the radial differential rotation in Sun-like stars. First, we developed an automated method for measuring the rotation of stars using surface variability. This method was initially applied to the entire Kepler catalog, out of which we detected signatures of rotation in 12,000 stars across the main sequence, providing robust estimates of the surface rotation rates and the associated errors. Second, we performed an asteroseismic analysis of six Sun-like stars, where we were able to measure the rotational splitting as a function of frequency in the p-mode envelope. This was done by dividing the oscillation spectrum into individual segments, and fitting a model independently to each segment. We found that the measured splittings were all consistent with a constant value, indicating little differential rotation. Third, we compared the asteroseismic rotation rates of five Sun-like stars to their surface rotation rates. We found that the values were in good agreement, again indicating little differential rotation between the regions where the two methods are most sensitive. Finally, we discuss how the surface rotation rates may be used as a prior on the seismic envelope rotation rate in a double-zone model

Rotations as coherent states of SU(6) quadrupole phonons in the SU(3) limit

Energy Technology Data Exchange (ETDEWEB)

Canto, L F [Rio de Janeiro Univ. (Brazil). Inst. de Fisica; Paar, V [Zagreb Univ. (Yugoslavia). Prirodoslovno Matematicki Fakultet; Rio de Janeiro Univ. (Brazil). Inst. de Fisica)

1981-06-18

Analytic expressions for the wavefunctions of the ground-state rotational band for even and odd nuclei are derived in terms of spherical quadrupole phonons truncated at N(max) phonons. For N(max) ..-->.. infinite the Bohr-Mottelson rotational states are generated as an asymptotic gaussian distribution of quadrupole phonons.

Influences on and Limitations of Classical Test Theory Reliability Estimates.

Science.gov (United States)

Arnold, Margery E.

It is incorrect to say "the test is reliable" because reliability is a function not only of the test itself, but of many factors. The present paper explains how different factors affect classical reliability estimates such as test-retest, interrater, internal consistency, and equivalent forms coefficients. Furthermore, the limits of classical test…

Plasma residual rotation in the TCABR tokamak

International Nuclear Information System (INIS)

Severo, J.H.F.; Nascimento, I.C.; Tsypin, V.S.; Galvao, R.M.O.

2003-01-01

This paper reports the first results on the measurement of the radial profiles of plasma poloidal and toroidal rotation performed on the TCABR tokamak, in the collisional regime (Pfirsch-Schluter), using Doppler shift of carbon spectral lines, measured with a high precision optical spectrometer. The results for poloidal rotation show a maximum velocity of (4.5±1.0) x 10 3 m s -1 at r ∼ 2/3a,(a-limiter radius), in the direction of the diamagnetic electron drift. Within the error limits, reasonable agreement is obtained with calculations using the neoclassical theory for a collisional plasma, except near the plasma edge, as expected. For toroidal rotation, the radial profile shows that the velocity decreases from a counter-current value of (20 ± 1) x 10 3 m s -1 , at the plasma core, to a co-current value of (2.0 ± 0.9) x 10 3 m s -1 near the limiter. An agreement within a factor 2, for the plasma core rotation, is obtained with calculations using the model proposed by Kim, Diamond and Groebner (1991 Phys. Fluids B 3 2050). (author)

Global robust stability of delayed neural networks: Estimating upper limit of norm of delayed connection weight matrix

International Nuclear Information System (INIS)

Singh, Vimal

2007-01-01

The question of estimating the upper limit of -parallel B -parallel 2 , which is a key step in some recently reported global robust stability criteria for delayed neural networks, is revisited ( B denotes the delayed connection weight matrix). Recently, Cao, Huang, and Qu have given an estimate of the upper limit of -parallel B -parallel 2 . In the present paper, an alternative estimate of the upper limit of -parallel B -parallel 2 is highlighted. It is shown that the alternative estimate may yield some new global robust stability results

Image acquisition optimization of a limited-angle intrafraction verification (LIVE) system for lung radiotherapy.

Science.gov (United States)

Zhang, Yawei; Deng, Xinchen; Yin, Fang-Fang; Ren, Lei

2018-01-01

Limited-angle intrafraction verification (LIVE) has been previously developed for four-dimensional (4D) intrafraction target verification either during arc delivery or between three-dimensional (3D)/IMRT beams. Preliminary studies showed that LIVE can accurately estimate the target volume using kV/MV projections acquired over orthogonal view 30° scan angles. Currently, the LIVE imaging acquisition requires slow gantry rotation and is not clinically optimized. The goal of this study is to optimize the image acquisition parameters of LIVE for different patient respiratory periods and gantry rotation speeds for the effective clinical implementation of the system. Limited-angle intrafraction verification imaging acquisition was optimized using a digital anthropomorphic phantom (XCAT) with simulated respiratory periods varying from 3 s to 6 s and gantry rotation speeds varying from 1°/s to 6°/s. LIVE scanning time was optimized by minimizing the number of respiratory cycles needed for the four-dimensional scan, and imaging dose was optimized by minimizing the number of kV and MV projections needed for four-dimensional estimation. The estimation accuracy was evaluated by calculating both the center-of-mass-shift (COMS) and three-dimensional volume-percentage-difference (VPD) between the tumor in estimated images and the ground truth images. The robustness of LIVE was evaluated with varied respiratory patterns, tumor sizes, and tumor locations in XCAT simulation. A dynamic thoracic phantom (CIRS) was used to further validate the optimized imaging schemes from XCAT study with changes of respiratory patterns, tumor sizes, and imaging scanning directions. Respiratory periods, gantry rotation speeds, number of respiratory cycles scanned and number of kV/MV projections acquired were all positively correlated with the estimation accuracy of LIVE. Faster gantry rotation speed or longer respiratory period allowed less respiratory cycles to be scanned and less kV/MV projections

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.

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.

Weight Estimation Tool for Children Aged 6 to 59 Months in Limited-Resource Settings.

Science.gov (United States)

Ralston, Mark E; Myatt, Mark A

2016-01-01

A simple, reliable anthropometric tool for rapid estimation of weight in children would be useful in limited-resource settings where current weight estimation tools are not uniformly reliable, nearly all global under-five mortality occurs, severe acute malnutrition is a significant contributor in approximately one-third of under-five mortality, and a weight scale may not be immediately available in emergencies to first-response providers. To determine the accuracy and precision of mid-upper arm circumference (MUAC) and height as weight estimation tools in children under five years of age in low-to-middle income countries. This was a retrospective observational study. Data were collected in 560 nutritional surveys during 1992-2006 using a modified Expanded Program of Immunization two-stage cluster sample design. Locations with high prevalence of acute and chronic malnutrition. A total of 453,990 children met inclusion criteria (age 6-59 months; weight ≤ 25 kg; MUAC 80-200 mm) and exclusion criteria (bilateral pitting edema; biologically implausible weight-for-height z-score (WHZ), weight-for-age z-score (WAZ), and height-for-age z-score (HAZ) values). Weight was estimated using Broselow Tape, Hong Kong formula, and database MUAC alone, height alone, and height and MUAC combined. Mean percentage difference between true and estimated weight, proportion of estimates accurate to within ± 25% and ± 10% of true weight, weighted Kappa statistic, and Bland-Altman bias were reported as measures of tool accuracy. Standard deviation of mean percentage difference and Bland-Altman 95% limits of agreement were reported as measures of tool precision. Database height was a more accurate and precise predictor of weight compared to Broselow Tape 2007 [B], Broselow Tape 2011 [A], and MUAC. Mean percentage difference between true and estimated weight was +0.49% (SD = 10.33%); proportion of estimates accurate to within ± 25% of true weight was 97.36% (95% CI 97.40%, 97.46%); and

Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens.

Science.gov (United States)

Piñero, David P; Camps, Vicente J; Ramón, María L; Mateo, Verónica; Pérez-Cambrodí, Rafael J

2015-01-01

To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay I). PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

Zero-point vibrational effects on optical rotation

DEFF Research Database (Denmark)

Ruud, K.; Taylor, P.R.; Åstrand, P.-O.

2001-01-01

We investigate the effects of molecular vibrations on the optical rotation in two chiral molecules, methyloxirane and trans-2,3-dimethylthiirane. It is shown that the magnitude of zero-point vibrational corrections increases as the electronic contribution to the optical rotation increases....... Vibrational effects thus appear to be important for an overall estimate of the molecular optical rotation, amounting to about 20-30% of the electronic counterpart. We also investigate the special case of chirality introduced in a molecule through isotopic substitution. In this case, the zero-point vibrational...

Valley-selective optical Stark effect probed by Kerr rotation

Science.gov (United States)

LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.

2018-01-01

The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.

Development of stair-climbing mechanism with passive crawlers. Analysis of limitation for crawler rotation angle and test vehicle performance

International Nuclear Information System (INIS)

Hirasawa, Junji; Kimura, Tetsuya

2016-01-01

This paper describes a novel mechanism with passive crawlers that will realize a stair-climbing rescue robot with simple system. The proposed mechanism is called 'SMART-III', it is named after 'Simple Mechanism Adaptive for Rough Terrain'. Some quasi-static dynamic analysis were implemented and effectiveness of limitation for crawler rotation angle were verified. A prototype robot with the SMART-III mechanism had been improved. Experimental results show the effectiveness and performance of the proposed mechanism against a step and continuous stairs. (author)

Faraday Rotation Measurement with the SMAP Radiometer

Science.gov (United States)

Le Vine, D. M.; Abraham, S.

2016-01-01

Faraday rotation is an issue that needs to be taken into account in remote sensing of parameters such as soil moisture and ocean salinity at L-band. This is especially important for SMAP because Faraday rotation varies with azimuth around the conical scan. SMAP retrieves Faraday rotation in situ using the ratio of the third and second Stokes parameters, a procedure that was demonstrated successfully by Aquarius. This manuscript reports the performance of this algorithm on SMAP. Over ocean the process works reasonably well and results compare favorably with expected values. But over land, the inhomogeneous nature of the scene results in much noisier, and in some cases unreliable estimates of Faraday rotation.

Asymmetric rotator as a detector of monochromatic gravitational waves

International Nuclear Information System (INIS)

Gliner, Eh.B.; Mitrofanov, I.G.

1979-01-01

The interaction between a rotating asymmetric (principal moments of inertia are different) body with a gravitational wave is considered. A resonance rotational detector of monocrhomatic gravitational waves is proposed in which the turning due to the incident wave and the rotation which ensures resonance between the detector and wave correspond to different degrees of freedom. This significantly facilitates the creation of such detectors. The interference due to the gradient of the gravitational acceleration of the Earth and to rotation of the detector as a whole is estimated

Equilibrium of rotating and nonrotating plasmas in tokamaks

International Nuclear Information System (INIS)

Pustovitov, V.D.

2003-01-01

One studied plasma equilibrium in tokamak in case of toroidal rotation. Rotation associated centrifugal force is shown to result in decrease of equilibrium limit as to β. One analyzes unlike opinion and considers its supports. It is shown that in possible case of local improvement of equilibrium conditions associated with special selection of profile of plasma rotation rate, the combined integral effect turns to be negative one. But in case of typical conditions, decrease of equilibrium β caused by plasma rotation is negligible one and one may ignore effect of plasma rotation on its equilibrium for hot plasma [ru

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

Patient-specific lean body mass can be estimated from limited-coverage computed tomography images.

Science.gov (United States)

Devriese, Joke; Beels, Laurence; Maes, Alex; van de Wiele, Christophe; Pottel, Hans

2018-06-01

In PET/CT, quantitative evaluation of tumour metabolic activity is possible through standardized uptake values, usually normalized for body weight (BW) or lean body mass (LBM). Patient-specific LBM can be estimated from whole-body (WB) CT images. As most clinical indications only warrant PET/CT examinations covering head to midthigh, the aim of this study was to develop a simple and reliable method to estimate LBM from limited-coverage (LC) CT images and test its validity. Head-to-toe PET/CT examinations were retrospectively retrieved and semiautomatically segmented into tissue types based on thresholding of CT Hounsfield units. LC was obtained by omitting image slices. Image segmentation was validated on the WB CT examinations by comparing CT-estimated BW with actual BW, and LBM estimated from LC images were compared with LBM estimated from WB images. A direct method and an indirect method were developed and validated on an independent data set. Comparing LBM estimated from LC examinations with estimates from WB examinations (LBMWB) showed a significant but limited bias of 1.2 kg (direct method) and nonsignificant bias of 0.05 kg (indirect method). This study demonstrates that LBM can be estimated from LC CT images with no significant difference from LBMWB.

Applications of lightweight composite materials in pulsed rotating electrical generators

International Nuclear Information System (INIS)

Walls, W.A.; Maifold, S.M.

1987-01-01

Present rotating electrical pulse power generators are limited in energy storage capability, specific energy, and peak power density by the use of iron-magnetic circuits. This paper discusses lightweight and compact iron-core homopolar generators (HPGs) which have attained specific energies of 6 kJ/kg and have the potential to achieve 8 kJ/kg in the near future. Prototype iron based pulsed alternators are the favored choice for high power to mass ratio applications and have estimated peak ratings of 180 kW/kg. In terms of total energy storage capability, these machines are limited to several hundred MJ due to the availability of large steel forgings for rotors and basic design considerations including rotor dynamics, allowable rotor tip speeds, and present high speed current collection technology

Estimation of single plane unbalance parameters of a rotor-bearing system using Kalman filtering based force estimation technique

Science.gov (United States)

Shrivastava, Akash; Mohanty, A. R.

2018-03-01

This paper proposes a model-based method to estimate single plane unbalance parameters (amplitude and phase angle) in a rotor using Kalman filter and recursive least square based input force estimation technique. Kalman filter based input force estimation technique requires state-space model and response measurements. A modified system equivalent reduction expansion process (SEREP) technique is employed to obtain a reduced-order model of the rotor system so that limited response measurements can be used. The method is demonstrated using numerical simulations on a rotor-disk-bearing system. Results are presented for different measurement sets including displacement, velocity, and rotational response. Effects of measurement noise level, filter parameters (process noise covariance and forgetting factor), and modeling error are also presented and it is observed that the unbalance parameter estimation is robust with respect to measurement noise.

Two methods for estimating limits to large-scale wind power generation.

Science.gov (United States)

Miller, Lee M; Brunsell, Nathaniel A; Mechem, David B; Gans, Fabian; Monaghan, Andrew J; Vautard, Robert; Keith, David W; Kleidon, Axel

2015-09-08

Wind turbines remove kinetic energy from the atmospheric flow, which reduces wind speeds and limits generation rates of large wind farms. These interactions can be approximated using a vertical kinetic energy (VKE) flux method, which predicts that the maximum power generation potential is 26% of the instantaneous downward transport of kinetic energy using the preturbine climatology. We compare the energy flux method to the Weather Research and Forecasting (WRF) regional atmospheric model equipped with a wind turbine parameterization over a 10(5) km2 region in the central United States. The WRF simulations yield a maximum generation of 1.1 We⋅m(-2), whereas the VKE method predicts the time series while underestimating the maximum generation rate by about 50%. Because VKE derives the generation limit from the preturbine climatology, potential changes in the vertical kinetic energy flux from the free atmosphere are not considered. Such changes are important at night when WRF estimates are about twice the VKE value because wind turbines interact with the decoupled nocturnal low-level jet in this region. Daytime estimates agree better to 20% because the wind turbines induce comparatively small changes to the downward kinetic energy flux. This combination of downward transport limits and wind speed reductions explains why large-scale wind power generation in windy regions is limited to about 1 We⋅m(-2), with VKE capturing this combination in a comparatively simple way.

Evolutionary optimization of rotational population transfer

Energy Technology Data Exchange (ETDEWEB)

Rouzee, Arnaud; Vrakking, Marc J. J. [FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, NL-1098 XG Amsterdam (Netherlands); Max Born Institut, Max Born Strasse 2A, D-12489, Berlin (Germany); Ghafur, Omair; Gijsbertsen, Arjan [FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, NL-1098 XG Amsterdam (Netherlands); Vidma, Konstantin; Meijer, Afric; Zande, Wim J. van der; Parker, David [Institute of Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, NL-6500 GL Nijmegen (Netherlands); Shir, Ofer M.; Baeck, Thomas [Leiden Institute of Advanced Computer Science (LIACS), Niels Bohrweg 1, NL-2333 CA Leiden (Netherlands)

2011-09-15

We present experimental and numerical studies on control of rotational population transfer of NO(J=1/2) molecules to higher rotational states. We are able to transfer 57% of the population to the J=5/2 state and 46% to J=9/2, in good agreement with quantum mechanical simulations. The optimal pulse shapes are composed of pulse sequences with delays corresponding to the beat frequencies of states on the rotational ladder. The evolutionary algorithm is limited by experimental constraints such as volume averaging and the finite laser intensity used, the latter to circumvent ionization. Without these constraints, near-perfect control (>98%) is possible. In addition, we show that downward control, moving molecules from high to low rotational states, is also possible.

Evolutionary optimization of rotational population transfer

International Nuclear Information System (INIS)

Rouzee, Arnaud; Vrakking, Marc J. J.; Ghafur, Omair; Gijsbertsen, Arjan; Vidma, Konstantin; Meijer, Afric; Zande, Wim J. van der; Parker, David; Shir, Ofer M.; Baeck, Thomas

2011-01-01

We present experimental and numerical studies on control of rotational population transfer of NO(J=1/2) molecules to higher rotational states. We are able to transfer 57% of the population to the J=5/2 state and 46% to J=9/2, in good agreement with quantum mechanical simulations. The optimal pulse shapes are composed of pulse sequences with delays corresponding to the beat frequencies of states on the rotational ladder. The evolutionary algorithm is limited by experimental constraints such as volume averaging and the finite laser intensity used, the latter to circumvent ionization. Without these constraints, near-perfect control (>98%) is possible. In addition, we show that downward control, moving molecules from high to low rotational states, is also possible.

Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades

Science.gov (United States)

Howard, Samuel A.; Hammer, Jeremiah T.; Carney, Kelly S.; Pereira, J. Michael

2013-01-01

Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990 to 2007 in the US alone (Ref. 1). As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a nonrotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests. NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the prestress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in

Estimation of Joint types and Joint Limits from Motion capture data

DEFF Research Database (Denmark)

Engell-Nørregård, Morten Pol; Erleben, Kenny

2009-01-01

It is time-consuming for an animator to explicitly model joint types and joint limits of articulated figures. In this paper we describe a simple and fast approach to automated joint estimation from motion capture data of articulated figures. Our method will make the joint modeling more efficient ...

Generation of plasma rotation by ICRH in tokamaks

International Nuclear Information System (INIS)

Chang, C.; Phillips, C.K.; White, R.B.; Zweben, S.; Bonoli, P.T.; Rice, J.; Greenwald, M.; Grassie, J.S. de

2001-01-01

A physical mechanism to generate plasma rotation by ICRH is presented in a tokamak geometry. By breaking the omnigenity of resonant ion orbits, ICRH can induce a non-ambipolar minor-radial flow of resonant ions. This induces a return current j p r in the plasma, which then drives plasma rotation through the j p r xB force. It is estimated that the fast-wave power in the present-day tokamak experiments can be strong enough to give a significant modification to plasma rotation. (author)

Composite Estimation for Single-Index Models with Responses Subject to Detection Limits

KAUST Repository

Tang, Yanlin; Wang, Huixia Judy; Liang, Hua

2017-01-01

We propose a semiparametric estimator for single-index models with censored responses due to detection limits. In the presence of left censoring, the mean function cannot be identified without any parametric distributional assumptions, but the quantile function is still identifiable at upper quantile levels. To avoid parametric distributional assumption, we propose to fit censored quantile regression and combine information across quantile levels to estimate the unknown smooth link function and the index parameter. Under some regularity conditions, we show that the estimated link function achieves the non-parametric optimal convergence rate, and the estimated index parameter is asymptotically normal. The simulation study shows that the proposed estimator is competitive with the omniscient least squares estimator based on the latent uncensored responses for data with normal errors but much more efficient for heavy-tailed data under light and moderate censoring. The practical value of the proposed method is demonstrated through the analysis of a human immunodeficiency virus antibody data set.

Composite Estimation for Single-Index Models with Responses Subject to Detection Limits

KAUST Repository

Tang, Yanlin

2017-11-03

We propose a semiparametric estimator for single-index models with censored responses due to detection limits. In the presence of left censoring, the mean function cannot be identified without any parametric distributional assumptions, but the quantile function is still identifiable at upper quantile levels. To avoid parametric distributional assumption, we propose to fit censored quantile regression and combine information across quantile levels to estimate the unknown smooth link function and the index parameter. Under some regularity conditions, we show that the estimated link function achieves the non-parametric optimal convergence rate, and the estimated index parameter is asymptotically normal. The simulation study shows that the proposed estimator is competitive with the omniscient least squares estimator based on the latent uncensored responses for data with normal errors but much more efficient for heavy-tailed data under light and moderate censoring. The practical value of the proposed method is demonstrated through the analysis of a human immunodeficiency virus antibody data set.

Estimating wind frequency limits for natural ventilation at remote sites

International Nuclear Information System (INIS)

Su, B.; Aynsley, R.

2006-01-01

Detailed wind data are collected at a limited number of sites, usually at airports. When a building is sited remote from the nearest wind data collection site, estimating wind frequency is more complex. The techniques involved come from the discipline of wind engineering. Where there is a relatively flat terrain between the wind data-recording site and the building site, simple computations can be made to account for the wind velocities over intervening terrain roughness. Where significant topographic features such as hills or mountains are present between the wind data-recording site and the building site, then boundary layer wind tunnel studies will be necessary to determine the influence of such features on wind speed and direction. Rough estimates can be calculated using factors used in some wind loading codes. When buildings are to be designed to take advantage of the energy efficiency offered by natural ventilation, it is important to estimate the actual potential for such ventilation. The natural ventilation potential can be estimated in terms of the percentage of time when wind exceeds some minimum value. For buildings near airports this is a relatively simple procedure. Such estimates are important as they also indicate the likely percentage of time when fans or other energy consuming devices will be needed to maintain indoor thermal comfort. This paper identifies the wind engineering techniques that can be used for such estimates and gives examples of such calculations

A Practical Guide for Estimating Dietary Fat and Fiber Using Limited Food Frequency Data.

Science.gov (United States)

Neale, Anne Victoria; And Others

1992-01-01

A methodology is presented for estimating daily intake of dietary fat and fiber based on limited food frequency data. The procedure, which relies on National Food Consumption Survey data and daily consumption rates, can provide baseline estimates of dietary patterns for health promotion policymakers. (SLD)

Rotation and rotation-vibration spectroscopy of the 0+-0- inversion doublet in deuterated cyanamide.

Science.gov (United States)

Kisiel, Zbigniew; Kraśnicki, Adam; Jabs, Wolfgang; Herbst, Eric; Winnewisser, Brenda P; Winnewisser, Manfred

2013-10-03

The pure rotation spectrum of deuterated cyanamide was recorded at frequencies from 118 to 649 GHz, which was complemented by measurement of its high-resolution rotation-vibration spectrum at 8-350 cm(-1). For D2NCN the analysis revealed considerable perturbations between the lowest Ka rotational energy levels in the 0(+) and 0(-) substates of the lowest inversion doublet. The final data set for D2NCN exceeded 3000 measured transitions and was successfully fitted with a Hamiltonian accounting for the 0(+) ↔ 0(-) coupling. A smaller data set, consisting only of pure rotation and rotation-vibration lines observed with microwave techniques was obtained for HDNCN, and additional transitions of this type were also measured for H2NCN. The spectroscopic data for all three isotopic species were fitted with a unified, robust Hamiltonian allowing confident prediction of spectra well into the terahertz frequency region, which is of interest to contemporary radioastronomy. The isotopic dependence of the determined inversion splitting, ΔE = 16.4964789(8), 32.089173(3), and 49.567770(6) cm(-1), for D2NCN, HDNCN, and H2NCN, respectively, is found to be in good agreement with estimates from a simple reduced quartic-quadratic double minimum potential.

Rotation, Stability and Transport

Energy Technology Data Exchange (ETDEWEB)

Connor, J. W.

2007-07-01

Tokamak plasmas can frequently exhibit high levels of rotation and rotation shear. This can usually be attributed to various sources: injection of momentum, e.g. through neutral beams, flows driven by plasma gradients or torques resulting from non-ambipolar particle loss; however, the source sometimes remains a mystery, such as the spontaneous rotation observed in Ohmic plasmas. The equilibrium rotation profile is given by the balance of these sources with transport and other losses; the edge boundary conditions can play an important role in determining this profile . Such plasma rotation, particularly sheared rotation, is predicted theoretically to have a significant influence on plasma behaviour. In the first place, sonic flows can significantly affect tokamak equilibria and neoclassical transport losses. However, the influence of rotation on plasma stability and turbulence is more profound. At the macroscopic level it affects the behaviour of the gross MHD modes that influence plasma operational limits. This includes sawteeth, the seeding of neoclassical tearing modes, resistive wall modes and the onset of disruptions through error fields, mode locking and reconnection. At the microscopic level it has a major effect on the stability of ballooning modes, both ideal MHD and drift wave instabilities such as ion temperature gradient (ITG) modes. In the non-linear state, as unstable drift waves evolve into turbulent structures, sheared rotation also tears apart eddies, thereby reducing the resulting transport. There is considerable experimental evidence for these effects on both MHD stability and plasma confinement. In particular, the appearance of improved confinement modes with transport barriers, such as edge H-mode barriers and internal transport barriers (ITBs) appears to correlate well with the presence of sheared plasma rotation. This talk will describe the theory underlying some of these phenomena involving plasma rotation, on both macroscopic and microscopic

Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

Directory of Open Access Journals (Sweden)

David P. Piñero

2015-06-01

Full Text Available AIM:To evaluate the prediction error in intraocular lens (IOL power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP.METHODS:Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany. In all cases, an adjusted IOL power (PIOLadj was calculated based on Gaussian optics using a variable keratometric index value (nkadj for the estimation of the corneal power (Pkadj and on a new value for ELP (ELPadj obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay Ⅰ.RESULTS:PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05. In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D and limits of agreement (of 1.47 and -1.61 D when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01 and was found to be dependent on axial length, anterior chamber depth and Pkadj.CONCLUSION:Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

Detection Thresholds for Rotation and Translation Gains in 360° Video-Based Telepresence Systems.

Science.gov (United States)

Zhang, Jingxin; Langbehn, Eike; Krupke, Dennis; Katzakis, Nicholas; Steinicke, Frank

2018-04-01

Telepresence systems have the potential to overcome limits and distance constraints of the real-world by enabling people to remotely visit and interact with each other. However, current telepresence systems usually lack natural ways of supporting interaction and exploration of remote environments (REs). In particular, single webcams for capturing the RE provide only a limited illusion of spatial presence, and movement control of mobile platforms in today's telepresence systems are often restricted to simple interaction devices. One of the main challenges of telepresence systems is to allow users to explore a RE in an immersive, intuitive and natural way, e.g., by real walking in the user's local environment (LE), and thus controlling motions of the robot platform in the RE. However, the LE in which the user's motions are tracked usually provides a much smaller interaction space than the RE. In this context, redirected walking (RDW) is a very suitable approach to solve this problem. However, so far there is no previous work, which explored if and how RDW can be used in video-based 360° telepresence systems. In this article, we conducted two psychophysical experiments in which we have quantified how much humans can be unknowingly redirected on virtual paths in the RE, which are different from the physical paths that they actually walk in the LE. Experiment 1 introduces a discrimination task between local and remote translations, and in Experiment 2 we analyzed the discrimination between local and remote rotations. In Experiment 1 participants performed straightforward translations in the LE that were mapped to straightforward translations in the RE shown as 360° videos, which were manipulated by different gains. Then, participants had to estimate if the remotely perceived translation was faster or slower than the actual physically performed translation. Similarly, in Experiment 2 participants performed rotations in the LE that were mapped to the virtual rotations

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

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)

Evaluation of Repair Tension in Arthroscopic Rotator Cuff Repair: Does It Really Matter to the Integrity of the Rotator Cuff?

Science.gov (United States)

Kim, Do Hoon; Jang, Young Hoon; Choi, Young Eun; Lee, Hwa-Ryeong; Kim, Sae Hoon

2016-11-01

Repair tension of a torn rotator cuff can affect healing after repair. However, a measurement of the actual tension during arthroscopic rotator cuff repair is not feasible. The relationship between repair tension and healing of a rotator cuff repair remains unclear. The purpose of this study was to evaluate the effect of repair tension on healing at the repair site. The hypothesis was that repair tension would be a major factor in determining the anatomic outcome of rotator cuff repair. Cohort study; Level of evidence, 2. Arthroscopic rotator cuff repairs (132 patients) for full-thickness rotator cuff tears were analyzed. An intraoperative model was designed for the estimation of repair tension using a tensiometer. Magnetic resonance imaging (MRI) was performed approximately 1 year (mean [±SD], 12.7 ± 3.2 months) postoperatively for the evaluation of healing at the repair site. Multivariable analysis was performed for tear size, amount of retraction, and fatty degeneration (FD) of rotator cuff muscles. The mean repair tension measured during the arthroscopic procedure was 28.5 ± 23.1 N. There was a statistically significant correlation between tension and tear size (Pearson correlation coefficient [PCC], 0.529; P repair tension also showed a significant inverse correlation with healing at the repair site (SCC, 0.195; P = .025). However, when sex, age, tear size, amount of retraction, tendon quality, and FD of rotator cuff muscles were included for multivariable logistic regression analysis, only FD of the infraspinatus showed an association with the anatomic outcome of repair (Exp(B) = 0.596; P = .010). Our intraoperative model for the estimation of rotator cuff repair tension showed an inverse correlation of repair tension with healing at the repair site, suggesting that complete healing is less likely with high-tension repairs. A significant association was observed on MRI between a high level of FD of the infraspinatus and repaired tendon integrity. © 2016

Number of discernible colors for color-deficient observers estimated from the MacAdam limits.

Science.gov (United States)

Perales, Esther; Martínez-Verdú, Francisco Miguel; Linhares, João Manuel Maciel; Nascimento, Sérgio Miguel Cardoso

2010-10-01

We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65, and the resultant colors were expressed in the CIELAB and DIN99d color spaces. The corresponding color volumes for abnormal color vision were computed using models simulating for normal trichromatic observers the appearance for dichromats and anomalous trichomats. The number of colors perceived in each case was then computed from the color volumes enclosed by the optimal colors also known as MacAdam limits. It was estimated that dichromats perceive less than 1% of the colors perceived by normal trichromats and that anomalous trichromats perceive 50%-60% for anomalies in the medium-wavelength-sensitive and 60%-70% for anomalies in the long-wavelength-sensitive cones. Complementary estimates obtained similarly for the spectral locus of monochromatic stimuli suggest less impairment for color-deficient observers, a fact that is explained by the two-dimensional nature of the locus.

Editorial Commentary: The Downstream Effects of Limited Hip Rotation and Femoroacetabular Impingement on the Anterior Cruciate Ligament: Could a Little Hip Stretching Every Day (or Surgery) Keep the Knee Doctor Away?

Science.gov (United States)

Boykin, Robert E

2018-03-01

Patients with radiographic evidence of femoroacetabular impingement and decreased hip internal rotation have a higher rate of anterior cruciate ligament (ACL) tears. Limited internal rotation of the hip increases strain and potentially resultant fatigue failure of the ACL. Although causation has not been proven, a better understanding of the lower extremity kinetic chain may allow improved ACL prevention strategies through measures (operative or nonoperative) to improve rotation of the hip. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Rotating neutron stars with exotic cores: masses, radii, stability

Energy Technology Data Exchange (ETDEWEB)

Haensel, P.; Bejger, M.; Fortin, M.; Zdunik, L. [Polish Academy of Sciences, N. Copernicus Astronomical Center, Warszawa (Poland)

2016-03-15

A set of theoretical mass-radius relations for rigidly rotating neutron stars with exotic cores, obtained in various theories of dense matter, is reviewed. Two basic observational constraints are used: the largest measured rotation frequency (716Hz) and the maximum measured mass (2M {sub CircleDot}). The present status of measuring the radii of neutron stars is described. The theory of rigidly rotating stars in general relativity is reviewed and limitations of the slow rotation approximation are pointed out. Mass-radius relations for rotating neutron stars with hyperon and quark cores are illustrated using several models. Problems related to the non-uniqueness of the crust-core matching are mentioned. Limits on rigid rotation resulting from the mass-shedding instability and the instability with respect to the axisymmetric perturbations are summarized. The problem of instabilities and of the back-bending phenomenon are discussed in detail. Metastability and instability of a neutron star core in the case of a first-order phase transition, both between pure phases, and into a mixed-phase state, are reviewed. The case of two disjoint families (branches) of rotating neutron stars is discussed and generic features of neutron-star families and of core-quakes triggered by the instabilities are considered. (orig.)

Effects of Density-Dependent Bag Constant and Strange Star Rotation

Institute of Scientific and Technical Information of China (English)

ZHOU Qiao-Er; GUO Hua

2003-01-01

With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresponding radius of strange star increase as the rotation frequency increases, and tend to be lowered when the density-dependent bag constant is considered.

Rotation of the Solar Equator

Science.gov (United States)

Kotov, V. A.

2017-06-01

Regular measurements of the general magnetic field of the Sun, performed over about half a century at the Crimean Astrophysical Observatory, the J. Wilcox Solar Observatory, and five other observatories, are considered in detail for the time 1968 - 2016. They include more than twenty-six thousand daily values of the mean line-of-sight field strength of the visible solar hemisphere. On the basis of these values, the equatorial rotation period of the Sun is found to be 26.926(9) d (synodic). It is shown that its half-value coincides within error limits with both the main period of the magnetic four-sector structure, 13.4577(25) d, and the best-commensurate period of the slow motions of the major solar system bodies, 13.479(22) d (sidereal). The probability that the two periods coincide by chance is estimated to be about 10^{-7}. The true origin of this odd resonance is unknown.

26Al yields from rotating Wolf--Rayet star models

OpenAIRE

Vuissoz, C.; Meynet, G.; Knoedlseder, J.; Cervino, M.; Schaerer, D.; Palacios, A.; Mowlavi, N.

2003-01-01

We present new $^{26}$Al stellar yields from rotating Wolf--Rayet stellar models which, at solar metallicity, well reproduce the observed properties of the Wolf-Rayet populations. These new yields are enhanced with respect to non--rotating models, even with respect to non--rotating models computed with enhanced mass loss rates. We briefly discuss some implications of the use of these new yields for estimating the global contribution of Wolf-Rayet stars to the quantity of $^{26}$Al now present...

Degradation model and application in life prediction of rotating-mechanism

International Nuclear Information System (INIS)

Zhou Yuhui

2009-01-01

The degradation data can provide additional information beyond that provided by the failure observations, both sets of observations need to be considered when doing inference on the statistical parameters of the product and system lifetime distributions. By the degradation model showing the wear out failure, the predicted results of mechanism life is more accurate. Strength is one of the important capabilities of the rotating mechanism. In this paper, the degradation data of strength are described as a stochastic process model. Accelerated tests expose the products to greater environmental stress levels so that we can obtain lifetime and degradation measurements in a more timely fashion. Using the Best Linear Unbiased Estimation (BLUE) Method, the parameters under the degradation path were estimated from the accelerated life test (ALT) data of the rotating mechanism. Based on solving the singularity of degradation equation, at any time the reliability is estimated by the using the strength-stress interference theory. So we can predict the life of the rotating mechanism. (authors)

Investigation of intrinsic toroidal rotation scaling in KSTAR

Science.gov (United States)

Yoo, J. W.; Lee, S. G.; Ko, S. H.; Seol, J.; Lee, H. H.; Kim, J. H.

2017-07-01

The behaviors of an intrinsic toroidal rotation without any external momentum sources are investigated in KSTAR. In these experiments, pure ohmic discharges with a wide range of plasma parameters are carefully selected and analyzed to speculate an unrevealed origin of toroidal rotation excluding any unnecessary heating sources, magnetic perturbations, and strong magneto-hydrodynamic activities. The measured core toroidal rotation in KSTAR is mostly in the counter-current direction and its magnitude strongly depends on the ion temperature divided by plasma current (Ti/IP). Especially the core toroidal rotation in the steady-state is well fitted by Ti/IP scaling with a slope of ˜-23, and the possible explanation of the scaling is compared with various candidates. As a result, the calculated offset rotation could not explain the measured core toroidal rotation since KSTAR has an extremely low intrinsic error field. For the stability conditions for ion and electron turbulences, it is hard to determine a dominant turbulence mode in this study. In addition, the intrinsic toroidal rotation level in ITER is estimated based on the KSTAR scaling since the intrinsic rotation plays an important role in stabilizing resistive wall modes for future reference.

Rotating Shaft Tilt Angle Measurement Using an Inclinometer

Science.gov (United States)

Luo, Jun; Wang, Zhiqian; Shen, Chengwu; Wen, Zhuoman; Liu, Shaojin; Cai, Sheng; Li, Jianrong

2015-10-01

This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

Rotating Shaft Tilt Angle Measurement Using an Inclinometer

Directory of Open Access Journals (Sweden)

Luo Jun

2015-10-01

Full Text Available This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

Differential rotation of stars with multiple transiting planets

Science.gov (United States)

Netto, Yuri; Valio, Adriana

2017-10-01

If a star hosts a planet in an orbit such that it eclipses the star periodically, can be estimated the rotation profile of this star. If planets in multiplanetary system occult different stellar areas, spots in more than one latitude of the stellar disc can be detected. The monitored study of theses starspots in different latitudes allow us to infer the rotation profile of the star. We use the model described in Silva (2003) to characterize the starspots of Kepler-210, an active star with two planets. Kepler-210 is a late K star with an estimated age of 350 +/- 50 Myrs, average rotation period of 12.33 days, mass of 0.63 M⊙ and radius of 0.69 R⊙. The planets that eclipses this star have radii of 0.0498 R s and 0.0635 R s with orbital periods of 2.4532 +/- 0.0007 days and 7.9725 +/- 0.0014 days, respectively, where R s is the star radius.

Exploration of factors limiting biomass estimation by polarimetric radar in tropical forests

NARCIS (Netherlands)

Quiñones Fernández, M.J.; Hoekman, D.H.

2004-01-01

Direct inversion of radar return signals for forest biomass estimation is limited by signal saturation at medium biomass levels (roughly 150 ton/ha for P-band). Disturbing factors such as forest structural differences-and, notably, at low biomass levels, terrain roughness, and soil moisture

Breakdown of I-Love-Q Universality in Rapidly Rotating Relativistic Stars

Science.gov (United States)

Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Stergioulas, Nikolaos; Kokkotas, Kostas D.

2014-01-01

It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz.

BREAKDOWN OF I-LOVE-Q UNIVERSALITY IN RAPIDLY ROTATING RELATIVISTIC STARS

International Nuclear Information System (INIS)

Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Kokkotas, Kostas D.; Stergioulas, Nikolaos

2014-01-01

It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz

Morphology of large rotator cuff tears and of the rotator cable and long-term shoulder disability in conservatively treated elderly patients.

Science.gov (United States)

Morag, Yoav; Jamadar, David A; Miller, Bruce; Brandon, Catherine; Gandikota, Girish; Jacobson, Jon A

2013-01-01

The objective of this study was to describe the morphology of the rotator cuff tendon tears and long-term shoulder disability in conservatively treated elderly patients and determine if an association exists between these factors. Assessment of the rotator cuff tendon tear dimensions and depth, rotator interval involvement, rotator cable morphology and location, and rotator cuff muscle status was carried out on magnetic resonance studies of 24 elderly patients treated nonoperatively for rotator cuff tendon tears. Long-term shoulder function was measured using the Western Ontario Rotator Cuff (WORC) index; Disabilities of the Shoulder, Arm, and Hand questionnaire; and the American Shoulder Elbow Self-assessment form, and a correlation between the outcome scores and morphologic magnetic resonance findings was carried out. The majority of large rotator cuff tendon tears are limited to the rotator cuff crescent. Medial rotator interval involvement (isolated or in association with lateral rotator interval involvement) was significantly associated with WORC physical symptoms total (P = 0.01), WORC lifestyle total (P = 0.04), percentage of all WORC domains (P = 0.03), and American Shoulder Elbow Self-assessment total (P = 0.01), with medial rotator interval involvement associated with an inferior outcome. Medial rotator interval tears are associated with long-term inferior outcome scores in conservatively treated elderly patients with large rotator cuff tendon tears.

Bayesian analysis of rotating machines - A statistical approach to estimate and track the fundamental frequency

DEFF Research Database (Denmark)

Pedersen, Thorkild Find

2003-01-01

frequency and the related frequencies as orders of the fundamental frequency. When analyzing rotating or reciprocating machines it is important to know the running speed. Usually this requires direct access to the rotating parts in order to mount a dedicated tachometer probe. In this thesis different......Rotating and reciprocating mechanical machines emit acoustic noise and vibrations when they operate. Typically, the noise and vibrations are concentrated in narrow frequency bands related to the running speed of the machine. The frequency of the running speed is referred to as the fundamental...

Snakes and spin rotators

International Nuclear Information System (INIS)

Lee, S.Y.

1990-01-01

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

Assessment and treatment strategies for rotator cuff tears

Science.gov (United States)

Al-Hakim, Wisam; Noorani, Ali

2014-01-01

Tears of the rotator cuff are common and becoming an increasingly frequent problem. There is a vast amount of literature on the merits and limitations of the various methods of clinical and radiological assessment of rotator cuff tears. This is also the case with regard to treatment strategies. Certain popular beliefs and principles practiced widely and the basis upon which they are derived may be prone to inaccuracy. We provide an overview of the historical management of rotator cuff tears, as well as an explanation for how and why rotator cuff tears should be managed, and propose a structured methodology for their assessment and treatment. PMID:27582960

SPECTRALLY RESOLVED PURE ROTATIONAL LINES OF WATER IN PROTOPLANETARY DISKS

International Nuclear Information System (INIS)

Pontoppidan, Klaus M.; Salyk, Colette; Blake, Geoffrey A.; Kaeufl, Hans Ulrich

2010-01-01

We present ground-based high-resolution N-band spectra (Δv = 15 km s -1 ) of pure rotational lines of water vapor in two protoplanetary disks surrounding the pre-main-sequence stars AS 205N and RNO 90, selected based on detections of rotational water lines by the Spitzer InfraRed Spectrograph. Using VISIR on the Very Large Telescope, we spectrally resolve individual lines and show that they have widths of 30-60 km s -1 , consistent with an origin in Keplerian disks at radii of ∼1 AU. The water lines have similar widths to those of the CO at 4.67 μm, indicating that the mid-infrared water lines trace similar radii. The rotational temperatures of the water are 540 and 600 K in the two disks, respectively. However, the line ratios show evidence of non-LTE excitation, with low-excitation line fluxes being overpredicted by two-dimensional disk LTE models. Due to the limited number of observed lines and the non-LTE line ratios, an accurate measure of the water ortho/para (O/P) ratio is not available, but a best estimate for AS 205N is O/P =4.5 ± 1.0, apparently ruling out a low-temperature origin of the water. The spectra demonstrate that high-resolution spectroscopy of rotational water lines is feasible from the ground, and further that ground-based high-resolution spectroscopy is likely to significantly improve our understanding of the inner disk chemistry revealed by recent Spitzer observations.

Rotationally resolved spectroscopy of Jupiter Trojans (624) Hektor and (911) Agamemnon

Science.gov (United States)

Perna, D.; Bott, N.; Hromakina, T.; Mazzotta Epifani, E.; Dotto, E.; Doressoundiram, A.

2018-03-01

We present the first-ever rotationally resolved spectroscopic investigation of (624) Hektor and (911) Agamemnon, the two largest Jupiter Trojans. The visible and near-infrared spectra that we have obtained at the TNG telescope (La Palma, Spain) do not show any feature or hints of heterogeneity. In particular, we found no hints of water-related absorptions. No cometary activity was detected down to ˜23.5 R mag arcsec-2 based on the complementary photometric data. We estimated upper limits on the dust production rates of Hektor and Agamemnon to be ≈30 and ≈24 kg s-1, respectively. We modelled complete visible and near-infrared spectra of our targets using the Shkuratov formalism to define the upper limit to the presence of water ice and more in general to constrain their surface composition. For both objects, successful models include amorphous carbon, magnesium-rich pyroxene, and kerogen, with an upper limit to the amount of water ice of a few per cent.

The Spatiale Rotator

DEFF Research Database (Denmark)

Rasmusson, Allan

2009-01-01

it is embedded and sectioned. This has the unfortunate side effect that all information about positioning within the object is lost for blocks and sections. For complex tissue, like the mammalian brain, this information is of utmost importance to ensure measurements are performed in the correct region......The inherent demand for unbiasedness for some stereological estimators imposes a demand of not only positional uniform randomness but also isotropic randomness, i.e. directional uniform randomness. In order to comply with isotropy, one must perform a random rotation of the object of interest before...... is obeyed by randomizing the orientation of the virtual probe itself within the thick section. Overall, the benefit is that positional information is kept for any block and section of the specimen. As the Spatial Rotator is a 3D probe, data must be gathered from sections thicker than 25 micro meters to form...

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.)

Rotation of vertically oriented objects during earthquakes

Science.gov (United States)

Hinzen, Klaus-G.

2012-10-01

Vertically oriented objects, such as tombstones, monuments, columns, and stone lanterns, are often observed to shift and rotate during earthquake ground motion. Such observations are usually limited to the mesoseismal zone. Whether near-field rotational ground motion components are necessary in addition to pure translational movements to explain the observed rotations is an open question. We summarize rotation data from seven earthquakes between 1925 and 2009 and perform analog and numeric rotation testing with vertically oriented objects. The free-rocking motion of a marble block on a sliding table is disturbed by a pulse in the direction orthogonal to the rocking motion. When the impulse is sufficiently strong and occurs at the `right' moment, it induces significant rotation of the block. Numeric experiments of a free-rocking block show that the initiation of vertical block rotation by a cycloidal acceleration pulse applied orthogonal to the rocking axis depends on the amplitude of the pulse and its phase relation to the rocking cycle. Rotation occurs when the pulse acceleration exceeds the threshold necessary to provoke rocking of a resting block, and the rocking block approaches its equilibrium position. Experiments with blocks subjected to full 3D strong motion signals measured during the 2009 L'Aquila earthquake confirm the observations from the tests with analytic ground motions. Significant differences in the rotational behavior of a monolithic block and two stacked blocks exist.

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.

Measurement of Resistive Wall Mode stability in rotating high beta plasmas

International Nuclear Information System (INIS)

Reimerdes, H.; Bialek, J.; Garofalo, A.M.; Navratil, G.A.; Chance, M.S.; Menard, J.E.; Okabayashi, M.; Takahashi, H.; Chu, M.S.; Gohil, P.; Jackson, G.L.; Jensen, T.H.; La Haye, R.J.; Scoville, J.T.; Strait, E.J.; Jayakumar, R.J.; Liu, Y.Q.

2005-01-01

Toroidal plasma rotation in the order of a few percent of the Alfven velocity can stabilize the resistive wall mode and extend the operating regime of tokamaks from the conventional, ideal MHD no-wall limit up to the ideal MHD ideal wall limit. The stabilizing effect has been measured passively by measuring the critical plasma rotation required for stability and actively by probing the plasma with externally applied resonant magnetic fields. These measurements are compared to predictions of rotational stabilization of the sound wave damping and of the kinetic damping model using the MARS code. (author)

Visualization and spectral synthesis of rotationally distorted stars

International Nuclear Information System (INIS)

Dall, T H; Sbordone, L

2011-01-01

Simple spherical, non-rotating stellar models are inadequate when describing real stars in the limit of very fast rotation: Both the observable spectrum and the geometrical shape of the star deviate strongly from simple models. We attempt to approach the problem of modeling geometrically distorted, rapidly rotating stars from a new angle: By constructing distorted geometrical models and integrating standard stellar models with varying temperature, gravity, and abundances, over the entire surface, we attempt a semi-empirical approach to modeling. Here we present our methodology, and present simple examples of applications.

Collective rotations of active particles interacting with obstacles

Science.gov (United States)

Mokhtari, Zahra; Aspelmeier, Timo; Zippelius, Annette

2017-10-01

We consider active particles in a heterogeneous medium, modeled by static, random obstacles. In accordance with the known tendency of active particles to cluster, we observe accumulation and crystallization of active particles around the obstacles which serve as nucleation sites. In the limit of high activity, the crystals start to rotate spontaneously, resembling a rotating rigid body. We trace the occurrence of these oscillations to the enhanced attraction of particles whose orientation points along the rotational velocity as compared to those whose orientation points in the opposite direction.

Relativistic theory of nuclear spin-rotation tensor with kinetically balanced rotational London orbitals

Energy Technology Data Exchange (ETDEWEB)

Xiao, Yunlong; Zhang, Yong; Liu, Wenjian, E-mail: liuwjbdf@gmail.com [Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, and Center for Computational Science and Engineering, Peking University, Beijing 100871 (China)

2014-10-28

Both kinetically balanced (KB) and kinetically unbalanced (KU) rotational London orbitals (RLO) are proposed to resolve the slow basis set convergence in relativistic calculations of nuclear spin-rotation (NSR) coupling tensors of molecules containing heavy elements [Y. Xiao and W. Liu, J. Chem. Phys. 138, 134104 (2013)]. While they perform rather similarly, the KB-RLO Ansatz is clearly preferred as it ensures the correct nonrelativistic limit even with a finite basis. Moreover, it gives rise to the same “direct relativistic mapping” between nuclear magnetic resonance shielding and NSR coupling tensors as that without using the London orbitals [Y. Xiao, Y. Zhang, and W. Liu, J. Chem. Theory Comput. 10, 600 (2014)].

The estimation of derived limits

International Nuclear Information System (INIS)

Harrison, N.T.; Bryant, P.M.; Clarke, R.H.; Morley, F.

1979-08-01

In practical radiation protection, it is often necessary to calculate limits of intake of radionuclides associated with various quantities; such limits are needed, for example, to assess the adequacy of the control of environmental contamination. In publication 26 of the International Commission on Radiological Protection (ICRP), these limits, when related to the basic limits of dose-equivalent by a defined model, are referred to as Derived Limits (DLs). In the present report the principles to be adopted by the Board in calculating DLs to be recommended for general application within the United Kingdom are outlined. DLs will be recommended for a wide range of radionuclides and for circumstances relevant to the workplace, and, more frequently, the general environment. The latter will include DLs in foodstuffs and associated environmental materials, such as soil and grass, and DLs for discharges from stacks. DLs will be related to dose equivalents for workers or members of the public for stochastic or non-stochastic effects as appropriate. Consideration will be given to relevant data on radiosensitivity, metabolism and dosimetry for children and to the physicochemical forms of radionuclides. (author)

Rotator cuff tendon connections with the rotator cable.

Science.gov (United States)

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

Passive RFID Rotation Dimension Reduction via Aggregation

Science.gov (United States)

Matthews, Eric

Radio Frequency IDentification (RFID) has applications in object identification, position, and orientation tracking. RFID technology can be applied in hospitals for patient and equipment tracking, stores and warehouses for product tracking, robots for self-localisation, tracking hazardous materials, or locating any other desired object. Efficient and accurate algorithms that perform localisation are required to extract meaningful data beyond simple identification. A Received Signal Strength Indicator (RSSI) is the strength of a received radio frequency signal used to localise passive and active RFID tags. Many factors affect RSSI such as reflections, tag rotation in 3D space, and obstacles blocking line-of-sight. LANDMARC is a statistical method for estimating tag location based on a target tag's similarity to surrounding reference tags. LANDMARC does not take into account the rotation of the target tag. By either aggregating multiple reference tag positions at various rotations, or by determining a rotation value for a newly read tag, we can perform an expected value calculation based on a comparison to the k-most similar training samples via an algorithm called K-Nearest Neighbours (KNN) more accurately. By choosing the average as the aggregation function, we improve the relative accuracy of single-rotation LANDMARC localisation by 10%, and any-rotation localisation by 20%.

Power dependence on the rotational strength in a quartz crystal

International Nuclear Information System (INIS)

Joshi, N.V.; Salcedo, D.; Gil, H.

2007-01-01

The rotational strength of optical activity has been examined as a function of power of the incident radiation in a quartz crystal for the first time. It has been observed that the angle of rotation is proportional to the square root of the intensity of the radiation. The present experimental data directly support the recently proposed model which takes into account the electronic polarizability rather than the atomic polarizability. This model explicitly explains the role of the incident power in estimating the angle of rotation

Theoretical prediction of a rotating magnon wave packet in ferromagnets.

Science.gov (United States)

Matsumoto, Ryo; Murakami, Shuichi

2011-05-13

We theoretically show that the magnon wave packet has a rotational motion in two ways: a self-rotation and a motion along the boundary of the sample (edge current). They are similar to the cyclotron motion of electrons, but unlike electrons the magnons have no charge and the rotation is not due to the Lorentz force. These rotational motions are caused by the Berry phase in momentum space from the magnon band structure. Furthermore, the rotational motion of the magnon gives an additional correction term to the magnon Hall effect. We also discuss the Berry curvature effect in the classical limit of long-wavelength magnetostatic spin waves having macroscopic coherence length.

Confidence limits for contribution plots in multivariate statistical process control using bootstrap estimates.

Science.gov (United States)

Babamoradi, Hamid; van den Berg, Frans; Rinnan, Åsmund

2016-02-18

In Multivariate Statistical Process Control, when a fault is expected or detected in the process, contribution plots are essential for operators and optimization engineers in identifying those process variables that were affected by or might be the cause of the fault. The traditional way of interpreting a contribution plot is to examine the largest contributing process variables as the most probable faulty ones. This might result in false readings purely due to the differences in natural variation, measurement uncertainties, etc. It is more reasonable to compare variable contributions for new process runs with historical results achieved under Normal Operating Conditions, where confidence limits for contribution plots estimated from training data are used to judge new production runs. Asymptotic methods cannot provide confidence limits for contribution plots, leaving re-sampling methods as the only option. We suggest bootstrap re-sampling to build confidence limits for all contribution plots in online PCA-based MSPC. The new strategy to estimate CLs is compared to the previously reported CLs for contribution plots. An industrial batch process dataset was used to illustrate the concepts. Copyright © 2016 Elsevier B.V. All rights reserved.

Tidal synchronization of an anelastic multi-layered body: Titan's synchronous rotation

Science.gov (United States)

Folonier, Hugo A.; Ferraz-Mello, Sylvio

2017-12-01

Tidal torque drives the rotational and orbital evolution of planet-satellite and star-exoplanet systems. This paper presents one analytical tidal theory for a viscoelastic multi-layered body with an arbitrary number of homogeneous layers. Starting with the static equilibrium figure, modified to include tide and differential rotation, and using the Newtonian creep approach, we find the dynamical equilibrium figure of the deformed body, which allows us to calculate the tidal potential and the forces acting on the tide generating body, as well as the rotation and orbital elements variations. In the particular case of the two-layer model, we study the tidal synchronization when the gravitational coupling and the friction in the interface between the layers is added. For high relaxation factors (low viscosity), the stationary solution of each layer is synchronous with the orbital mean motion ( n) when the orbit is circular, but the rotational frequencies increase if the orbital eccentricity increases. This behavior is characteristic in the classical Darwinian theories and in the homogeneous case of the creep tide theory. For low relaxation factors (high viscosity), as in planetary satellites, if friction remains low, each layer can be trapped in different spin-orbit resonances with frequencies n/2,n,3n/2,2n,\\ldots . When the friction increases, attractors with differential rotations are destroyed, surviving only commensurabilities in which core and shell have the same velocity of rotation. We apply the theory to Titan. The main results are: (i) the rotational constraint does not allow us to confirm or reject the existence of a subsurface ocean in Titan; and (ii) the crust-atmosphere exchange of angular momentum can be neglected. Using the rotation estimate based on Cassini's observation (Meriggiola et al. in Icarus 275:183-192, 2016), we limit the possible value of the shell relaxation factor, when a deep subsurface ocean is assumed, to γ _s≲ 10^{-9} s^{-1}, which

Molecular rotation and dynamics in superfluid helium-4 nanodroplets

Science.gov (United States)

Callegari, Carlo

2000-11-01

Cavity-enhanced laser radiation, coupled to molecular- beam bolometric detection has been used to study the spectroscopy of acetylenic molecules embedded in helium nanodroplets. The 2ν1 transition (CH stretch overtone) of HCN, DCCH, NCCCH, CH3CCH, CF3CCH, (CH 3)3CCCH, (CH3)3SiCCH, has been investigated in the 1.5 μm spectral region by means of a color center laser coupled to a resonant build-up cavity, which enhances the laser power experienced by the molecules in the beam by up to a factor of 400, thus overcoming the weakness of the (dipole forbidden) transitions. All molecules are observed to rotate freely in the liquid cluster environment, with strongly enhanced moments of inertia, but with negligible matrix induced shifts (less than 1 cm-1). We show that this enhancement is largely accounted for by hydrodynamic effects, which we have modeled and numerically calculated. While in the gas phase the rotational lines have instrument-limited widths (a few MHZ), in the droplets we have observed linewidths ranging from 600 MHz for (CH3)3SiCCH to 2.8GHz for (CH3) 3CCCH. To investigate the nature of the broadening (which was widely believed to be homogeneous), we have performed a series of infrared (IR) saturation experiments on the 2ν1 transition. We have also thoroughly investigated NCCCH by means of microwave (MW) single-resonance experiments (on rotational transitions) and double-resonance (MW-MW and MW-IR) experiments. The results demonstrate that the spectral features of molecules in He droplets are inhomogeneously broadened, and allow an estimate of the importance of the different broadening contributions. In particular, MW-IR measurements show that the size of the cluster greatly affects the way rotational energy is relaxed. Large clusters seem to follow a ``strong collision model'' where memory of the initial rotational state is completely lost after each ``relaxation'' event, while for smaller clusters relaxation rates are probably affected by the lower

Molecular rotation and dynamics in superfluid ^4He nanodroplets

Science.gov (United States)

Callegari, Carlo

2001-05-01

Cavity-enhanced laser radiation, coupled to molecular-beam bolometric detection has been used to study the spectroscopy of acetylenic molecules embedded in helium nanodroplets. The 2ν1 transition (CH stretch overtone) of HCN, DCCH, NCCCH, CH_3CCH, CF_3CCH, (CH_3)_3CCCH, (CH_3)_3SiCCH, has been investigated in the 1.5 μm spectral region by means of a color center laser coupled to a resonant buildup cavity, which enhances the laser power experienced by the molecules in the beam by up to a factor of 400, thus overcoming the weakness of the (harmonically forbidden) transitions. All molecules are observed to rotate freely in the liquid cluster environment, with strongly enhanced moments of inertia, but with negligible matrix induced shifts (less than 1 cm-1). We show that this enhancement is largely accounted for by hydrodynamic effects, which we have modeled and numerically calculated. While in the gas phase the rotational lines have instrument-limited widths (a few MHz), in the droplets we have observed linewidths ranging from 600 MHz for (CH_3)_3SiCCH to 2.8 GHz for (CH_3)_3CCCH. To investigate the nature of the broadening (which was widely believed to be homogeneous), we have performed a series of infrared (IR) saturation experiments on the 2ν1 transition. We have also thoroughly investigated NCCCH by means of microwave (MW) single-resonance experiments (on rotational transitions) and double-resonance (MW-MW and MW-IR) experiments. The results demonstrate that the spectral features of molecules in He droplets are inhomogeneously broadened, and allow an estimate of the importance of the different broadening contributions. In particular, MW-IR measurements show that the size of the cluster greatly affects the way rotational energy is relaxed. Large clusters seem to follow a ``strong collision model'' where memory of the initial rotational state is completely lost after each ``relaxation'' event, while for smaller clusters relaxation rates are probably affected by

Possible rotation-power nature of SGRs and AXPs

International Nuclear Information System (INIS)

Malheiro, M.; Lobato, R. V.; Coelho, Jaziel G.; Cáceres, D. L.; De Lima, R. C. R.; Rueda, J. A.; Ruffini, R.

2017-01-01

We investigate the possibility of some Soft Gamma-ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) could be described as rotation-powered neutron stars (NSs). The analysis was carried out by computing the structure properties of NSs, and then we focus on giving estimates for the surface magnetic field using both realistic structure parameters of NSs and a general relativistic model of a rotating magnetic dipole. We show that the use of realistic parameters of rotating neutron stars obtained from numerical integration of the self-consistent axisymmetric general relativistic equations of equilibrium leads to values of the magnetic field and radiation efficiency of SGRs/AXPs very different from estimates based on fiducial parameters. This analysis leads to a precise prediction of the range of NS masses, obtained here by making use of selected up-to-date nuclear equations of state (EOS). We show that 40% (nine) of the entire observed population of SGRs and AXPs can be described as canonical pulsars driven by the rotational energy of neutron stars, for which we give their possible range of masses. We also show that if the blackbody component in soft X-rays is due to the surface temperature of NSs, then 50% of the sources could be explained as ordinary rotation-powered pulsars. Besides, amongst these sources we find the four SGRs/AXPs with observed radio emission and six that are possibly associated with supernova remnants (including Swift J1834.9-0846 as the first magnetar to show a surrounding wind nebula), suggesting as well a natural explanation as ordinary pulsars. (paper)

Socio-ecological implications of modifying rotation lengths in forestry.

Science.gov (United States)

Roberge, Jean-Michel; Laudon, Hjalmar; Björkman, Christer; Ranius, Thomas; Sandström, Camilla; Felton, Adam; Sténs, Anna; Nordin, Annika; Granström, Anders; Widemo, Fredrik; Bergh, Johan; Sonesson, Johan; Stenlid, Jan; Lundmark, Tomas

2016-02-01

The rotation length is a key component of even-aged forest management systems. Using Fennoscandian forestry as a case, we review the socio-ecological implications of modifying rotation lengths relative to current practice by evaluating effects on a range of ecosystem services and on biodiversity conservation. The effects of shortening rotations on provisioning services are expected to be mostly negative to neutral (e.g. production of wood, bilberries, reindeer forage), while those of extending rotations would be more varied. Shortening rotations may help limit damage by some of today's major damaging agents (e.g. root rot, cambium-feeding insects), but may also increase other damage types (e.g. regeneration pests) and impede climate mitigation. Supporting (water, soil nutrients) and cultural (aesthetics, cultural heritage) ecosystem services would generally be affected negatively by shortened rotations and positively by extended rotations, as would most biodiversity indicators. Several effect modifiers, such as changes to thinning regimes, could alter these patterns.

Estimating health workforce needs for antiretroviral therapy in resource-limited settings

Directory of Open Access Journals (Sweden)

Fullem Andrew

2006-01-01

Full Text Available Abstract Background Efforts to increase access to life-saving treatment, including antiretroviral therapy (ART, for people living with HIV/AIDS in resource-limited settings has been the growing focus of international efforts. One of the greatest challenges to scaling up will be the limited supply of adequately trained human resources for health, including doctors, nurses, pharmacists and other skilled providers. As national treatment programmes are planned, better estimates of human resource needs and improved approaches to assessing the impact of different staffing models are critically needed. However there have been few systematic assessments of staffing patterns in existing programmes or of the estimates being used in planning larger programmes. Methods We reviewed the published literature and selected plans and scaling-up proposals, interviewed experts and collected data on staffing patterns at existing treatment sites through a structured survey and site visits. Results We found a wide range of staffing patterns and patient-provider ratios in existing and planned treatment programmes. Many factors influenced health workforce needs, including task assignments, delivery models, other staff responsibilities and programme size. Overall, the number of health care workers required to provide ART to 1000 patients included 1–2 physicians, 2–7 nurses, Discussion These data are consistent with other estimates of human resource requirements for antiretroviral therapy, but highlight the considerable variability of current staffing models and the importance of a broad range of factors in determining personnel needs. Few outcome or cost data are currently available to assess the effectiveness and efficiency of different staffing models, and it will be important to develop improved methods for gathering this information as treatment programmes are scaled up.

Self-gravitating axially symmetric disks in general-relativistic rotation

Science.gov (United States)

Karkowski, Janusz; Kulczycki, Wojciech; Mach, Patryk; Malec, Edward; Odrzywołek, Andrzej; Piróg, Michał

2018-05-01

We integrate numerically axially symmetric stationary Einstein equations describing self-gravitating disks around spinless black holes. The numerical scheme is based on a method developed by Shibata, but contains important new ingredients. We derive a new general-relativistic Keplerian rotation law for self-gravitating disks around spinning black holes. Former results concerning rotation around spinless black holes emerge in the limit of a vanishing spin parameter. These rotation curves might be used for the description of rotating stars, after appropriate modification around the symmetry axis. They can be applied to the description of compact torus-black hole configurations, including active galactic nuclei or products of coalescences of two neutron stars.

Mass transport at rotating disk electrodes: effects of synthetic particles and nerve endings.

Science.gov (United States)

Chiu, Veronica M; Lukus, Peter A; Doyle, Jamie L; Schenk, James O

2011-11-01

An unstirred layer (USL) exists at the interface of solids with solutions. Thus, the particles in brain tissue preparations possess a USL as well as at the surface of a rotating disk electrode (RDE) used to measure chemical fluxes. Time constraints for observing biological kinetics based on estimated thicknesses of USLs at the membrane surface in real samples of nerve endings were estimated. Liposomes, silica, and Sephadex were used separately to model the tissue preparation particles. Within a solution stirred by the RDE, both diffusion and hydrodynamic boundary layers are formed. It was observed that the number and size of particles decreased the following: the apparent diffusion coefficient excluding Sephadex, boundary layer thicknesses excluding silica, sensitivity excluding diluted liposomes (in agreement with results from other laboratories), limiting current potentially due to an increase in the path distance, and mixing time. They have no effect on the detection limit (6 ± 2 nM). The RDE kinetically resolves transmembrane transport with a timing of approximately 30 ms. Copyright © 2011 Elsevier Inc. All rights reserved.

SUBMILLIMETER-WAVE ROTATIONAL SPECTROSCOPY OF H2F+

International Nuclear Information System (INIS)

Fujimori, R.; Kawaguchi, K.; Amano, T.

2011-01-01

Five pure rotational transitions of H 2 F + generated by a discharge in an HF/H 2 /Ar mixture were observed in the range 473-774 GHz with a backward-wave oscillator based submillimeter-wave spectrometer. A simultaneous analysis of the rotational lines with 120 combination differences for the ground state derived from the infrared spectra was carried out to determine the precise molecular constants for the ground state. The rotational transition frequencies that lie below 2 THz were calculated, together with their estimated uncertainties, to facilitate future astronomical identifications. The chemistry for H 2 F + formation in interstellar space is discussed in comparison with a case for recently detected H 2 Cl + .

A procedure for estimating site specific derived limits for the discharge of radioactive material to the atmosphere

CERN Document Server

Hallam, J; Jones, J A

1983-01-01

Generalised Derived Limits (GDLs) for the discharge of radioactive material to the atmosphere are evaluated using parameter values to ensure that the exposure of the critical group is unlikely to be underestimated significantly. Where the discharge is greater than about 5% of the GDL, a more rigorous estimate of the derived limit may be warranted. This report describes a procedure for estimating site specific derived limits for discharges of radioactivity to the atmosphere taking into account the conditions of the release and the location and habits of the exposed population. A worksheet is provided to assist in carrying out the required calculations.

Benchmarking density-functional-theory calculations of rotational g tensors and magnetizabilities using accurate coupled-cluster calculations.

Science.gov (United States)

Lutnaes, Ola B; Teale, Andrew M; Helgaker, Trygve; Tozer, David J; Ruud, Kenneth; Gauss, Jürgen

2009-10-14

An accurate set of benchmark rotational g tensors and magnetizabilities are calculated using coupled-cluster singles-doubles (CCSD) theory and coupled-cluster single-doubles-perturbative-triples [CCSD(T)] theory, in a variety of basis sets consisting of (rotational) London atomic orbitals. The accuracy of the results obtained is established for the rotational g tensors by careful comparison with experimental data, taking into account zero-point vibrational corrections. After an analysis of the basis sets employed, extrapolation techniques are used to provide estimates of the basis-set-limit quantities, thereby establishing an accurate benchmark data set. The utility of the data set is demonstrated by examining a wide variety of density functionals for the calculation of these properties. None of the density-functional methods are competitive with the CCSD or CCSD(T) methods. The need for a careful consideration of vibrational effects is clearly illustrated. Finally, the pure coupled-cluster results are compared with the results of density-functional calculations constrained to give the same electronic density. The importance of current dependence in exchange-correlation functionals is discussed in light of this comparison.

Semiclassical description of quantum rotator in terms of SU(2) coherent states

International Nuclear Information System (INIS)

Gitman, D M; Petrusevich, D A; Shelepin, A L

2013-01-01

We introduce coordinates of the rigid body (rotator) using mutual positions between body-fixed and space-fixed reference frames. Wave functions that depend on such coordinates can be treated as scalar functions of the group SU(2). Irreducible representations of the group SU(2) × SU(2) in the space of such functions describe their possible transformations under independent rotations of the both reference frames. We construct sets of the corresponding group SU(2) × SU(2) Perelomov coherent states (CS) with a fixed angular momentum j of the rotator as special orbits of the latter group. Minimization of different uncertainty relations is discussed. The classical limit corresponds to the limit j → ∞. Considering Hamiltonians of rotators with different characteristics, we study the time evolution of the constructed CS. In some cases, the CS time evolution is completely or partially reduced to their parameter time evolution. If these parameters are chosen as Euler angles, then they obey the Euler equations in the classical limit. Quantum corrections to the motion of the quantum rotator can be found from exact equations on the CS parameters. (paper)

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate{sub N} simulation model

Energy Technology Data Exchange (ETDEWEB)

Guo Ruiying [Ministry of Education Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, No. 222 Tianshui Nanlu, Lanzhou 730000, Gansu Province (China); Nendel, Claas, E-mail: nendel@zalf.d [Institute for Landscape Systems Analysis, Leibniz-Center for Agricultural Landscape Research, Eberswalder Strasse 84, 15374 Muencheberg (Germany); Rahn, Clive [Warwick HRI, Wellesbourne CV35 9EF (United Kingdom); Jiang Chunguang; Chen Qing [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing 100193 (China)

2010-06-15

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate{sub N} simulation model. EU-Rotate{sub N} was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter. - The EU-Rotate{sub N} model can satisfactorily simulate crop N uptake and N{sub min} dynamics in a typical greenhouse cucumber production system of North China

Parity nonconserving optical rotation in atomic lead

International Nuclear Information System (INIS)

Emmons, T.P. Jr.

1984-01-01

A measurement of parity nonconserving optical rotation has been performed on the 1.28 μm atomic lead magnetic dipole transition. Although the technique used in this measurement was similar to that used in earlier measurements done on the 0.876 μm line in atomic bismuth, important differences exist. These are discussed in detail. Since the accuracy of this measurement is limited by systematic errors, a complete analysis of the data is included with a lengthy discussion of systematic effects. The final value obtained for the optical rotation is given. This agrees with atomic calculations based on the Weinberg-Salam-Galshow model for weak interactions. A discussion of the limits on weak interaction theories placed by all the atomic parity nonconservation experiments appears in the conclusion

Estimating the snowfall limit in alpine and pre-alpine valleys: A local evaluation of operational approaches

Science.gov (United States)

Fehlmann, Michael; Gascón, Estíbaliz; Rohrer, Mario; Schwarb, Manfred; Stoffel, Markus

2018-05-01

The snowfall limit has important implications for different hazardous processes associated with prolonged or heavy precipitation such as flash floods, rain-on-snow events and freezing precipitation. To increase preparedness and to reduce risk in such situations, early warning systems are frequently used to monitor and predict precipitation events at different temporal and spatial scales. However, in alpine and pre-alpine valleys, the estimation of the snowfall limit remains rather challenging. In this study, we characterize uncertainties related to snowfall limit for different lead times based on local measurements of a vertically pointing micro rain radar (MRR) and a disdrometer in the Zulg valley, Switzerland. Regarding the monitoring, we show that the interpolation of surface temperatures tends to overestimate the altitude of the snowfall limit and can thus lead to highly uncertain estimates of liquid precipitation in the catchment. This bias is much smaller in the Integrated Nowcasting through Comprehensive Analysis (INCA) system, which integrates surface station and remotely sensed data as well as outputs of a numerical weather prediction model. To reduce systematic error, we perform a bias correction based on local MRR measurements and thereby demonstrate the added value of such measurements for the estimation of liquid precipitation in the catchment. Regarding the nowcasting, we show that the INCA system provides good estimates up to 6 h ahead and is thus considered promising for operational hydrological applications. Finally, we explore the medium-range forecasting of precipitation type, especially with respect to rain-on-snow events. We show for a selected case study that the probability for a certain precipitation type in an ensemble-based forecast is more persistent than the respective type in the high-resolution forecast (HRES) of the European Centre for Medium Range Weather Forecasts Integrated Forecasting System (ECMWF IFS). In this case study, the

Wave-driven Rotation in Supersonically Rotating Mirrors

Energy Technology Data Exchange (ETDEWEB)

A. Fetterman and N.J. Fisch

2010-02-15

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

Wave-driven Rotation in Supersonically Rotating Mirrors

International Nuclear Information System (INIS)

Fetterman, A.; Fisch, N.J.

2010-01-01

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

Fouling in a MBR system with rotating membrane discs

DEFF Research Database (Denmark)

Jørgensen, Mads Koustrup; Bentzen, Thomas Ruby; Christensen, Morten Lykkegaard

concentrations and a clear effluent with no bacteria present in the permeate [1]. However, the process performance is limited by membrane fouling, which results in a lower productivity and higher energy demand and hence places demands for limitation of fouling and/or cleaning of the membranes. One way to do...... uses rotating ceramic membrane discs for creation of shear, which can be changed by controlling the membrane rotation speed of the membrane. Furthermore, the influence of shear on fouling is studied at different radii from the center of rotation, by dividing membranes into different concentric rings......Membrane bioreactors (MBR) are an attractive alternative solution for municipal and industrial wastewater treatment. The MBR, which is a combination of a bioreactor for sludge degradation and a membrane for separation, has the advantages of a low footprint, ability to handle high sludge...

Estimation of Radiation Limit from a Huygens' Box under Non-Free-Space Conditions

DEFF Research Database (Denmark)

Franek, Ondrej; Sørensen, Morten; Bonev, Ivan Bonev

2013-01-01

The recently studied Huygens' box method has difficulties when radiation of an electronic module is to be determined under non-free-space conditions, i.e. with an enclosure. We propose an estimate on radiation limit under such conditions based only on the Huygens' box data from free...

Dependence of Shear and Concentration on Fouling in a Membrane Bioreactor with Rotating Membrane Discs

DEFF Research Database (Denmark)

Jørgensen, Mads Koustrup; Pedersen, Malene Thostrup; Christensen, Morten Lykkegaard

2014-01-01

Rotating ceramic membrane discs were fouled with lab-scale membrane bioreactors (MBR) sludge. Sludge filtrations were performed at varying rotation speeds and in different concentric rings of the membranes on different sludge concentrations. Data showed that the back transport expressed by limiting...... flux increased with rotation speed and distance from membrane center as an effect of shear. Further, the limiting flux decreased with increasing sludge concentration. A model was developed to link the sludge concentration and shear stress to the limiting flux. The model was able to simulate the effect...... of shear stress and sludge concentration on the limiting flux. The model was developed by calculating the shear rate at laminar flow regime at different rotation speeds and radii on the membrane. Furthermore, through the shear rate and shear stress, the non-Newtonian behavior of MBR sludge was addressed...

A Faraday rotation search for magnetic fields in quasar damped Ly alpha absorption systems

Science.gov (United States)

Oren, Abraham L.; Wolfe, Arthur M.

1995-01-01

We present the results of a Faraday rotation survey of 61 radio-bright QSOs conducted at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA). The Galactic contribution to the Faraday rotation is estimated and subtracted to determine the extragalactic rotation measure (RRM) for each source. Eleven of these QSOs are known to exhibit damped Ly alpha absorption. The rate of incidence of significant Faraday rotation of these 11 sources is compared to the remaining 50 and is found to be higher at the 99.8% confidence level. However, as this is based upon only two detections of Faraday rotation in the damped Ly alpha sample, the result is only tentative. If the two detections in the damped Ly alpha sample are dug to the absorbing systems, then the inferred rotation measure induced by these systems is roughly 250 rad/sq m. The two detections were for the two lowest redshift absorbers in the sample. We find that a rotation measure of 250 rad/sq m would have gone undetected for any other absorber in the damped Ly alpha sample due to the 1/(1 + 2) squared dilution of the observed RRM with redshift. Thus the data are consistent with, but do not prove, the hypothesis that Faraday rotation is a generic property of damped Ly alpha absorbers. We do not confirm the suggestion that the amplitude of RRMs increases with redshift. Rather, the data are consistent with no redshift evolution. We find that the uncertainty in the estimation of the Galactic rotation measure (GRM) is a more serious problem than previously realized for extra-galactic Faraday rotation studies of QSO absorbers. A careful analysis of current methods for estimating GRM indicate that it can be determined to an accuracy of about 15 - 20 rad/sq m. Previous studies underestimated this uncertainty by more than a factor of 2. Due to this uncertainty, rotation measures such as we suspect are associated with damped Ly alpha absorption systems can only be detected at redshifts less than z approximately

Effects of Successive Rotation Regimes on Carbon Stocks in Eucalyptus Plantations in Subtropical China Measured over a Full Rotation.

Science.gov (United States)

Li, Xiaoqiong; Ye, Duo; Liang, Hongwen; Zhu, Hongguang; Qin, Lin; Zhu, Yuling; Wen, Yuanguang

2015-01-01

Plantations play an important role in carbon sequestration and the global carbon cycle. However, there is a dilemma in that most plantations are managed on short rotations, and the carbon sequestration capacities of these short-rotation plantations remain understudied. Eucalyptus has been widely planted in the tropics and subtropics due to its rapid growth, high adaptability, and large economic return. Eucalyptus plantations are primarily planted in successive rotations with a short rotation length of 6~8 years. In order to estimate the carbon-stock potential of eucalyptus plantations over successive rotations, we chose a first rotation (FR) and a second rotation (SR) stand and monitored the carbon stock dynamics over a full rotation from 1998 to 2005. Our results showed that carbon stock in eucalyptus trees (TC) did not significantly differ between rotations, while understory vegetation (UC) and soil organic matter (SOC) stored less carbon in the SR (1.01 vs. 2.76 Mg.ha(-1) and 70.68 vs. 81.08 Mg. ha(-1), respectively) and forest floor carbon (FFC) conversely stored more (2.80 vs. 2.34 Mg. ha(-1)). The lower UC and SOC stocks in the SR stand resulted in 1.13 times lower overall ecosystem carbon stock. Mineral soils and overstory trees were the two dominant carbon pools in eucalyptus plantations, accounting for 73.77%~75.06% and 20.50%~22.39%, respectively, of the ecosystem carbon pool. However, the relative contribution (to the ecosystem pool) of FFC stocks increased 1.38 times and that of UC decreased 2.30 times in the SR versus FR stand. These carbon pool changes over successive rotations were attributed to intensive successive rotation regimes of eucalyptus plantations. Our eight year study suggests that for the sustainable development of short-rotation plantations, a sound silvicultural strategy is required to achieve the best combination of high wood yield and carbon stock potential.

Effects of Successive Rotation Regimes on Carbon Stocks in Eucalyptus Plantations in Subtropical China Measured over a Full Rotation.

Directory of Open Access Journals (Sweden)

Xiaoqiong Li

Full Text Available Plantations play an important role in carbon sequestration and the global carbon cycle. However, there is a dilemma in that most plantations are managed on short rotations, and the carbon sequestration capacities of these short-rotation plantations remain understudied. Eucalyptus has been widely planted in the tropics and subtropics due to its rapid growth, high adaptability, and large economic return. Eucalyptus plantations are primarily planted in successive rotations with a short rotation length of 6~8 years. In order to estimate the carbon-stock potential of eucalyptus plantations over successive rotations, we chose a first rotation (FR and a second rotation (SR stand and monitored the carbon stock dynamics over a full rotation from 1998 to 2005. Our results showed that carbon stock in eucalyptus trees (TC did not significantly differ between rotations, while understory vegetation (UC and soil organic matter (SOC stored less carbon in the SR (1.01 vs. 2.76 Mg.ha(-1 and 70.68 vs. 81.08 Mg. ha(-1, respectively and forest floor carbon (FFC conversely stored more (2.80 vs. 2.34 Mg. ha(-1. The lower UC and SOC stocks in the SR stand resulted in 1.13 times lower overall ecosystem carbon stock. Mineral soils and overstory trees were the two dominant carbon pools in eucalyptus plantations, accounting for 73.77%~75.06% and 20.50%~22.39%, respectively, of the ecosystem carbon pool. However, the relative contribution (to the ecosystem pool of FFC stocks increased 1.38 times and that of UC decreased 2.30 times in the SR versus FR stand. These carbon pool changes over successive rotations were attributed to intensive successive rotation regimes of eucalyptus plantations. Our eight year study suggests that for the sustainable development of short-rotation plantations, a sound silvicultural strategy is required to achieve the best combination of high wood yield and carbon stock potential.

Faraday Rotation and L Band Oceanographic Measurements

DEFF Research Database (Denmark)

Skou, Niels

2003-01-01

Spaceborne radiometric measurements of the L band brightness temperature over the oceans make it possible to estimate sea surface salinity. However, Faraday rotation in the ionosphere disturbs the signals and must be corrected. Two different ways of assessing the disturbance directly from...

Rotation of the Mass Donors in High-mass X-ray Binaries and Symbiotic Stars

Directory of Open Access Journals (Sweden)

K. Stoyanov

2015-02-01

Full Text Available Our aim is to investigate the tidal interaction in High-mass X-ray Binaries and Symbiotic stars in order to determine in which objects the rotation of the mass donors is synchronized or pseudosynchronized with the orbital motion of the compact companion. We find that the Be/X-ray binaries are not synchronized and the orbital periods of the systems are greater than the rotational periods of the mass donors. The giant and supergiant High-mass X-ray binaries and symbiotic stars are close to synchronization. We compare the rotation of mass donors in symbiotics with the projected rotational velocities of field giants and find that the M giants in S-type symbiotics rotate on average 1.5 times faster than the field M giants. We find that the projected rotational velocity of the red giant in symbiotic star MWC 560 is v sin i= 8.2±1.5 km.s−1, and estimate its rotational period to be Prot<>/sub = 144 - 306 days. Using the theoretical predictions of tidal interaction and pseudosynchronization, we estimate the orbital eccentricity e = 0.68 − 0.82.

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

Estimation of the lower flammability limit of organic compounds as a function of temperature.

Science.gov (United States)

Rowley, J R; Rowley, R L; Wilding, W V

2011-02-15

A new method of estimating the lower flammability limit (LFL) of general organic compounds is presented. The LFL is predicted at 298 K for gases and the lower temperature limit for solids and liquids from structural contributions and the ideal gas heat of formation of the fuel. The average absolute deviation from more than 500 experimental data points is 10.7%. In a previous study, the widely used modified Burgess-Wheeler law was shown to underestimate the effect of temperature on the lower flammability limit when determined in a large-diameter vessel. An improved version of the modified Burgess-Wheeler law is presented that represents the temperature dependence of LFL data determined in large-diameter vessels more accurately. When the LFL is estimated at increased temperatures using a combination of this model and the proposed structural-contribution method, an average absolute deviation of 3.3% is returned when compared with 65 data points for 17 organic compounds determined in an ASHRAE-style apparatus. Copyright © 2010 Elsevier B.V. All rights reserved.

A novel vibration-based fault diagnostic algorithm for gearboxes under speed fluctuations without rotational speed measurement

Science.gov (United States)

Hong, Liu; Qu, Yongzhi; Dhupia, Jaspreet Singh; Sheng, Shuangwen; Tan, Yuegang; Zhou, Zude

2017-09-01

The localized failures of gears introduce cyclic-transient impulses in the measured gearbox vibration signals. These impulses are usually identified from the sidebands around gear-mesh harmonics through the spectral analysis of cyclo-stationary signals. However, in practice, several high-powered applications of gearboxes like wind turbines are intrinsically characterized by nonstationary processes that blur the measured vibration spectra of a gearbox and deteriorate the efficacy of spectral diagnostic methods. Although order-tracking techniques have been proposed to improve the performance of spectral diagnosis for nonstationary signals measured in such applications, the required hardware for the measurement of rotational speed of these machines is often unavailable in industrial settings. Moreover, existing tacho-less order-tracking approaches are usually limited by the high time-frequency resolution requirement, which is a prerequisite for the precise estimation of the instantaneous frequency. To address such issues, a novel fault-signature enhancement algorithm is proposed that can alleviate the spectral smearing without the need of rotational speed measurement. This proposed tacho-less diagnostic technique resamples the measured acceleration signal of the gearbox based on the optimal warping path evaluated from the fast dynamic time-warping algorithm, which aligns a filtered shaft rotational harmonic signal with respect to a reference signal assuming a constant shaft rotational speed estimated from the approximation of operational speed. The effectiveness of this method is validated using both simulated signals from a fixed-axis gear pair under nonstationary conditions and experimental measurements from a 750-kW planetary wind turbine gearbox on a dynamometer test rig. The results demonstrate that the proposed algorithm can identify fault information from typical gearbox vibration measurements carried out in a resource-constrained industrial environment.

Relative Pose Estimation Algorithm with Gyroscope Sensor

Directory of Open Access Journals (Sweden)

Shanshan Wei

2016-01-01

Full Text Available This paper proposes a novel vision and inertial fusion algorithm S2fM (Simplified Structure from Motion for camera relative pose estimation. Different from current existing algorithms, our algorithm estimates rotation parameter and translation parameter separately. S2fM employs gyroscopes to estimate camera rotation parameter, which is later fused with the image data to estimate camera translation parameter. Our contributions are in two aspects. (1 Under the circumstance that no inertial sensor can estimate accurately enough translation parameter, we propose a translation estimation algorithm by fusing gyroscope sensor and image data. (2 Our S2fM algorithm is efficient and suitable for smart devices. Experimental results validate efficiency of the proposed S2fM algorithm.

Atmospheric acceleration and Earth-expansion deceleration of the Earth rotation

Directory of Open Access Journals (Sweden)

Wenbin Shen

2017-11-01

Full Text Available Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation deceleration. Atmospheric solar semi-diurnal tide has a small amplitude and certain amount of phase lead. This periodic global air-mass excess distribution exerts a quasi-constant torque to accelerate the Earth's spin rotation. Using an updated atmospheric tide model, we re-estimate the amounts of this atmospheric acceleration torque and corresponding energy input, of which the associated change rate in LOD (length of day is −0.1 ms/cy. In another aspect, evidences from space-geodesy and sea level rise observations suggest that Earth expands at a rate of 0.35 mm/yr in recent decades, which gives rise to the increase of LOD at rate of 1.0 ms/cy. Hence, if the previous estimate due to the tidal friction is correct, the secular Earth rotation deceleration due to tidal friction and Earth expansion should be 3.15 ms/cy.

A New Stem Taper Function for Short-rotation poplar

Energy Technology Data Exchange (ETDEWEB)

Benbrahim, Mohammed [INRA Centre de Bordeaux, Cestas (France). Unite de Recherches Forestieres; Gavaland, Andre [INRA Centre de Toulouse, Castanet-Tolosane (France). Unite Agroforesterie et Foret Paysanne

2003-07-01

A new stem taper function was established for individual trees of two poplar hybrid clones grown on a short-rotation coppice. The model could be easily fitted and required three parameters to be estimated. It can be used to estimate both diameter at a given height and height for a given top diameter. Two of the three parameters controlled the conical and the neiloid parts of the stem. Significant differences in these parameters were observed between the two clones even if no differences were observed for diameter at breast height or total height of the stem. The model could not be integrated to calculate volumes (total volume, merchantable volume), which were estimated by numerical integration. However, use of this new model allows the optimal length of billets to be determined and thus maximizes the merchantable biomass of poplar in short-rotation coppice by minimizing the biomass of residues.

Estimation of unemployment rates using small area estimation model by combining time series and cross-sectional data

Science.gov (United States)

Muchlisoh, Siti; Kurnia, Anang; Notodiputro, Khairil Anwar; Mangku, I. Wayan

2016-02-01

Labor force surveys conducted over time by the rotating panel design have been carried out in many countries, including Indonesia. Labor force survey in Indonesia is regularly conducted by Statistics Indonesia (Badan Pusat Statistik-BPS) and has been known as the National Labor Force Survey (Sakernas). The main purpose of Sakernas is to obtain information about unemployment rates and its changes over time. Sakernas is a quarterly survey. The quarterly survey is designed only for estimating the parameters at the provincial level. The quarterly unemployment rate published by BPS (official statistics) is calculated based on only cross-sectional methods, despite the fact that the data is collected under rotating panel design. The study purpose to estimate a quarterly unemployment rate at the district level used small area estimation (SAE) model by combining time series and cross-sectional data. The study focused on the application and comparison between the Rao-Yu model and dynamic model in context estimating the unemployment rate based on a rotating panel survey. The goodness of fit of both models was almost similar. Both models produced an almost similar estimation and better than direct estimation, but the dynamic model was more capable than the Rao-Yu model to capture a heterogeneity across area, although it was reduced over time.

Calibrated Tully-fisher Relations For Improved Photometric Estimates Of Disk Rotation Velocities

NARCIS (Netherlands)

Reyes, Reinabelle; Mandelbaum, R.; Gunn, J. E.; Pizagno II, Jim

We present calibrated scaling relations (also referred to as Tully-Fisher relations or TFRs) between rotation velocity and photometric quantities-- absolute magnitude, stellar mass, and synthetic magnitude (a linear combination of absolute magnitude and color)-- of disk galaxies at z 0.1. First, we

Short Rotation Forestry (SRF in a Mediterranean Environment Under Limited Energy Inputs

Directory of Open Access Journals (Sweden)

Antonio Sergio De Franchi

2010-10-01

Full Text Available The aim of this work is comparing the two year performance (diameter, total height and mortality of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter. Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa, Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing. Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants. Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row. Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed

Short Rotation Forestry (SRF in a Mediterranean Environment Under Limited Energy Inputs

Directory of Open Access Journals (Sweden)

Stella Lovelli

2010-12-01

Full Text Available The aim of this work is comparing the two year performance (diameter, total height and mortality of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter. Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa, Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing. Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants. Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row. Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed

Rotating flow

CERN Document Server

Childs, Peter R N

2010-01-01

Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

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

Site establishment practices influence loblolly pine mortality throughout the stand rotation

Science.gov (United States)

Felipe G. Sanchez; Robert J. Eaton

2010-01-01

During a rotation, land managers need to estimate yields, update inventories, and evaluate stand dynamics. All of these factors in land management are heavily influenced by tree mortality. Tree mortality can, in turn, be influenced by land management practices from the inception of the stand and throughout the rotation. We describe the impact of organic matter removal...

Scale interactions in compressible rotating fluids

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard; Novotný, A.

2014-01-01

Roč. 193, č. 6 (2014), s. 1703-1725 ISSN 0373-3114 Keywords : compressible fluid * rotating fluid * singular limit Subject RIV: BA - General Mathematics Impact factor: 1.065, year: 2014 http://link.springer.com/article/10.1007%2Fs10231-013-0353-7

Three-dimensional coating and rimming flow: a ring of fluid on a rotating horizontal cylinder

KAUST Repository

Leslie, G. A.

2013-01-29

The steady three-dimensional flow of a thin, slowly varying ring of Newtonian fluid on either the outside or the inside of a uniformly rotating large horizontal cylinder is investigated. Specifically, we study \\'full-ring\\' solutions, corresponding to a ring of continuous, finite and non-zero thickness that extends all of the way around the cylinder. In particular, it is found that there is a critical solution corresponding to either a critical load above which no full-ring solution exists (if the rotation speed is prescribed) or a critical rotation speed below which no full-ring solution exists (if the load is prescribed). We describe the behaviour of the critical solution and, in particular, show that the critical flux, the critical load, the critical semi-width and the critical ring profile are all increasing functions of the rotation speed. In the limit of small rotation speed, the critical flux is small and the critical ring is narrow and thin, leading to a small critical load. In the limit of large rotation speed, the critical flux is large and the critical ring is wide on the upper half of the cylinder and thick on the lower half of the cylinder, leading to a large critical load. We also describe the behaviour of the non-critical full-ring solution and, in particular, show that the semi-width and the ring profile are increasing functions of the load but, in general, non-monotonic functions of the rotation speed. In the limit of large rotation speed, the ring approaches a limiting non-uniform shape, whereas in the limit of small load, the ring is narrow and thin with a uniform parabolic profile. Finally, we show that, while for most values of the rotation speed and the load the azimuthal velocity is in the same direction as the rotation of the cylinder, there is a region of parameter space close to the critical solution for sufficiently small rotation speed in which backflow occurs in a small region on the upward-moving side of the cylinder. © 2013

Three-dimensional coating and rimming flow: a ring of fluid on a rotating horizontal cylinder

KAUST Repository

Leslie, G. A.; Wilson, S. K.; Duffy, B. R.

2013-01-01

The steady three-dimensional flow of a thin, slowly varying ring of Newtonian fluid on either the outside or the inside of a uniformly rotating large horizontal cylinder is investigated. Specifically, we study 'full-ring' solutions, corresponding to a ring of continuous, finite and non-zero thickness that extends all of the way around the cylinder. In particular, it is found that there is a critical solution corresponding to either a critical load above which no full-ring solution exists (if the rotation speed is prescribed) or a critical rotation speed below which no full-ring solution exists (if the load is prescribed). We describe the behaviour of the critical solution and, in particular, show that the critical flux, the critical load, the critical semi-width and the critical ring profile are all increasing functions of the rotation speed. In the limit of small rotation speed, the critical flux is small and the critical ring is narrow and thin, leading to a small critical load. In the limit of large rotation speed, the critical flux is large and the critical ring is wide on the upper half of the cylinder and thick on the lower half of the cylinder, leading to a large critical load. We also describe the behaviour of the non-critical full-ring solution and, in particular, show that the semi-width and the ring profile are increasing functions of the load but, in general, non-monotonic functions of the rotation speed. In the limit of large rotation speed, the ring approaches a limiting non-uniform shape, whereas in the limit of small load, the ring is narrow and thin with a uniform parabolic profile. Finally, we show that, while for most values of the rotation speed and the load the azimuthal velocity is in the same direction as the rotation of the cylinder, there is a region of parameter space close to the critical solution for sufficiently small rotation speed in which backflow occurs in a small region on the upward-moving side of the cylinder. © 2013 Cambridge

Comparison of Two Methods for Estimation of Work Limitation Scores from Health Status Measures

DEFF Research Database (Denmark)

Anatchkova, M; Fang, H; Kini, N

2015-01-01

Objectives To compare two methods for estimation of Work Limitations Questionnaire scores (WLQ, 8 items) from the Role Physical (RP, 4 items) and Role Emotional scales (RE, 3 items) of the SF-36 Health survey. These measures assess limitations in role performance attributed to health (emotional...... future data collection strategies. Methods We used data from two independent cross-sectional panel samples (Sample1, n=1382, 51% female, 72% Caucasian, 49% with preselected chronic conditions, 15% with fair/poor health; Sample2, n=301, 45% female, 90% Caucasian, 47% with preselected chronic conditions......, 21% with fair/poor health). Method 1 used previously developed and validated IRT based calibration tables. Method 2 used regression models to develop aggregate imputation weights as described in the literature. We evaluated the agreement of observed and estimated WLQ scale scores from the two methods...

EBR-II rotating plug seal maintenance

International Nuclear Information System (INIS)

Allen, K.J.

1986-01-01

The EBR-II rotating plug seals require frequent cleaning and maintenance to keep the plugs from sticking during fuel handling. Time consuming cleaning on the cover gas and air sides of the dip ring seal is required to remove oxidation and sodium reaction products that accumulate and stop plug rotation. Despite severely limited access, effective seal cleaning techniques have removed 11 800 lb (5 352 kg) of deposits from the seals since 1964. Temperature control modifications and repairs have also required major maintenance work. Suggested seal design recommendations could significantly reduce maintenance on future similar seals

Understand rotating isothermal collapses yet

International Nuclear Information System (INIS)

Tohline, J.E.

1985-01-01

A scalar virial equation is used to describe the dynamic properties of equilibrium gas clouds, taking into account the relative effects of surface pressure, rotation, self gravity and internal isothermal pressure. Details concerning the internal structure of the clouds are ignored in order to obtain a globalized analytical expression. The obtained solution to the equation is found to agree with the surface-pressure-dominated model of Stahler (1983), and the rotation-dominated model of Hayashi, Narita, and Miyama (1982). On the basis of the analytical expression of virial equilibrium in the clouds, some of the limiting properties of isothermal clouds are described, and a realistic starting model for cloud collapse is proposed. 18 references

Vortex Noise from Rotating Cylindrical Rods

Science.gov (United States)

Stowell, E Z; Deming, A F

1935-01-01

A series of round rods of the some diameter were rotated individually about the mid-point of each rod. Vortices are shed from the rods when in motion, giving rise to the emission of sound. With the rotating system placed in the open air, the distribution of sound in space, the acoustical power output, and the spectral distribution have been studied. The frequency of emission of vortices from any point on the rod is given by the formula von Karman. From the spectrum estimates are made of the distribution of acoustical power along the rod, the amount of air concerned in sound production, the "equivalent size" of the vortices, and the acoustical energy content for each vortex.

First measurement of poloidal-field-induced Faraday rotation in a tokamak plasma

International Nuclear Information System (INIS)

Kunz, W.; Association Euratom-CEA sur la Fusion, Centre d'Etudes Nucleaires de Fontenay-aux-Roses, 92

1978-01-01

Faraday rotation measurements using a ferrite modulation technique were performed on one channel of the 337 μm-interferometer on TFR. The experiment is intended as a preparatory step towards poloidal-field determination on the basis of the Faraday effect in a multi-channel configuration. The technical feasibility of precise Faraday rotation measurements under machine conditions is demonstrated. The measured rotation is unambiguously due to the poloidal magnetic field and agrees fairly with what can be estimated. (author)

Biomaterials based strategies for rotator cuff repair.

Science.gov (United States)

Zhao, Song; Su, Wei; Shah, Vishva; Hobson, Divia; Yildirimer, Lara; Yeung, Kelvin W K; Zhao, Jinzhong; Cui, Wenguo; Zhao, Xin

2017-09-01

Tearing of the rotator cuff commonly occurs as among one of the most frequently experienced tendon disorders. While treatment typically involves surgical repair, failure rates to achieve or sustain healing range from 20 to 90%. The insufficient capacity to recover damaged tendon to heal to the bone, especially at the enthesis, is primarily responsible for the failure rates reported. Various types of biomaterials with special structures have been developed to improve tendon-bone healing and tendon regeneration, and have received considerable attention for replacement, reconstruction, or reinforcement of tendon defects. In this review, we first give a brief introduction of the anatomy of the rotator cuff and then discuss various design strategies to augment rotator cuff repair. Furthermore, we highlight current biomaterials used for repair and their clinical applications as well as the limitations in the literature. We conclude this article with challenges and future directions in designing more advanced biomaterials for augmentation of rotator cuff repair. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Secular instability of axisymmetric rotating stars to gravitational radiation reaction

International Nuclear Information System (INIS)

Managan, R.A.

1985-01-01

A generalization of the Eulerian variational principle derived by Ipser and Managan, for nonaxisymmetric neutral modes of axisymmetric fluid configurations, is developed. The principle provides a variational basis for calculating the frequencies of nonaxisymmetric normal modes proportional to e/sup i/(sigmat + mphi). A modified form of this principle, valid for sigma near 0, is also developed. The latter principle is used to locate the points where the frequency of a nonaxisymmetric normal mode of an axisymmetric rotating fluid configuration passes through zero. lt is at these points that the configuration becomes secularly unstable to gravitational radiation reaction (GRR). This is demonstrated directly by including the GRR potential and showing that the imaginary part of sigma passes through zero and becomes negative at these points. The imaginary part of the frequency is used to estimate the e-folding time of the mode. This variational principle is applied to sequences of rotating polytropes. The sequences are constructed using four rotation laws at each value of the polytropic index n = 0.5, 1.0, 1.5, 2.0, and 3.0. The values of (T/W)/sub m/, the ratio of the rotational kinetic energy to the magnitude of the gravitational potential energy at the onset of instability, and timescales for the modes with m = 2, 3, and 4 are estimated for each sequence. The value of (T/W) 2 is largely independent of the equation of state and rotation law. For m > 2, (T/W)/sub m/ decreases as the equation of state becomes softer, i.e., as the polytropic index n increases, and increases as the amount of differential rotation increases. The most striking result of this behavior occurs for uniform rotation

Ultraspinning limits and super-entropic black holes

Energy Technology Data Exchange (ETDEWEB)

Hennigar, Robie A. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Kubizňák, David [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Perimeter Institute, 31 Caroline St. N., Waterloo, Ontario, N2L 2Y5 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Musoke, Nathan [Perimeter Institute, 31 Caroline St. N., Waterloo, Ontario, N2L 2Y5 (Canada)

2015-06-16

By employing the new ultraspinning limit we construct novel classes of black holes with non-compact event horizons and finite horizon area and study their thermodynamics. Our ultraspinning limit can be understood as a simple generating technique that consists of three steps: i) transforming the known rotating AdS black hole solution to a special coordinate system that rotates (in a given 2-plane) at infinity ii) boosting this rotation to the speed of light iii) compactifying the corresponding azimuthal direction. In so doing we qualitatively change the structure of the spacetime since it is no longer possible to return to a frame that does not rotate at infinity. The obtained black holes have non-compact horizons with topology of a sphere with two punctures. The entropy of some of these exceeds the maximal bound implied by the reverse isoperimetric inequality, such black holes are super-entropic.

Ultraspinning limits and super-entropic black holes

Science.gov (United States)

Hennigar, Robie A.; Kubizňák, David; Mann, Robert B.; Musoke, Nathan

2015-06-01

By employing the new ultraspinning limit we construct novel classes of black holes with non-compact event horizons and finite horizon area and study their thermo-dynamics. Our ultraspinning limit can be understood as a simple generating technique that consists of three steps: i) transforming the known rotating AdS black hole solution to a special coordinate system that rotates (in a given 2-plane) at infinity ii) boosting this rotation to the speed of light iii) compactifying the corresponding azimuthal direction. In so doing we qualitatively change the structure of the spacetime since it is no longer pos-sible to return to a frame that does not rotate at infinity. The obtained black holes have non-compact horizons with topology of a sphere with two punctures. The entropy of some of these exceeds the maximal bound implied by the reverse isoperimetric inequality, such black holes are super-entropic.

Observing atmospheric tides in Earth rotation parameters with VLBI

Science.gov (United States)

Girdiuk, Anastasiia; Böhm, Johannes; Schindelegger, Michael

2015-04-01

In this study, we assess the contribution of diurnal (S1) and semi-diurnal (S2) atmospheric tides to variations in Earth rotation by analyzing Very Long Baseline Interferometry (VLBI) observations. Particular emphasis is placed on the dependency of S1 and S2 estimates on varying settings in the a priori delay model. We use hourly Earth rotation parameters (ERP) of polar motion and UT1 as determined with the Vienna VLBI Software (VieVS) from 25 years of VLBI observations and we adjust diurnal and semi-diurnal amplitudes to the hourly ERP estimates after disregarding the effect of high-frequency ocean tides. Prograde and retrograde polar motion coefficients are obtained for several solutions differing in processing strategies (with/without thermal deformation, time span of observations, choice of a priori ERP model and celestial pole offsets) and we compare the corresponding harmonics with those derived from atmospheric and non-tidal oceanic angular momentum estimates.

A nonsingular rotating black hole

International Nuclear Information System (INIS)

Ghosh, Sushant G.

2015-01-01

The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

Estimation of process capability indices from the results of limit gauge inspection of dimensional parameters in machining industry

Science.gov (United States)

Masterenko, Dmitry A.; Metel, Alexander S.

2018-03-01

The process capability indices Cp, Cpk are widely used in the modern quality management as statistical measures of the ability of a process to produce output X within specification limits. The customer's requirement to ensure Cp ≥ 1.33 is often applied in contracts. Capability indices estimates may be calculated with the estimates of the mean µ and the variability 6σ, and for it, the quality characteristic in a sample of pieces should be measured. It requires, in turn, using advanced measuring devices and well-qualified staff. From the other hand, quality inspection by attributes, fulfilled with limit gauges (go/no-go) is much simpler and has a higher performance, but it does not give the numerical values of the quality characteristic. The described method allows estimating the mean and the variability of the process on the basis of the results of limit gauge inspection with certain lower limit LCL and upper limit UCL, which separates the pieces into three groups: where X control of the manufacturing process. It is very important for improving quality of articles in machining industry through their tolerance.

An estimation on the derived limits of effluent water concentration

International Nuclear Information System (INIS)

Okamura, Yasuharu; Kobayashi, Katuhiko; Kusama, Tomoko; Yoshizawa, Yasuo

1984-01-01

The values of Derived Limits of Effluent Water Concentration, (DLEC)sub(w), have been estimated in accordance with the principles of the recent recommendations of the International Commission on Radiological Protection. The (DLEC)sub(w)'s were derived from the Annual Limits on Intake for individual members of the public (ALIsub(p)), considering realistic models of exposure pathways and annual intake rates of foods. The ALIsub(p)'s were decided after consideration of body organ mass and other age dependent parameters. We assumed that the materials which brought exposure to the public were drinking water, fish, seaweed, invertebrate and seashore. The age dependence of annual intake rate of food might be proportional to a person's energy expenditure rate. The following results were obtained. Infants were the critical group of the public at the time of derivation of (DLEC)sub(w). The ALIsub(p)'s for the infants were about one-hundredth of those for workers and their (DLEC)sub(w)'s were about one-third of those for the adult members of the public. (author)

ROTATION PERIODS OF OPEN-CLUSTER STARS .3.

NARCIS (Netherlands)

PROSSER, CF; SHETRONE, MD; DASGUPTA, A; BACKMAN, DE; LAAKSONEN, BD; BAKER, SW; MARSCHALL, LA; WHITNEY, BA; KUIJKEN, K; STAUFFER, [No Value

We present the results from a photometric monitoring program of 15 open cluster stars and one weak-lined T Tauri star during late 1993/early 1994. Several slow rotators which are members of the Alpha Persei, Pleiades, and Hyades open clusters have been monitored and period estimates derived. Using

Photometric light curves for seven rapidly-rotating K dwarfs in the Pleiades and Alpha Persei clusters

Science.gov (United States)

Stauffer, John R.; Schild, Rudolph A.; Baliunas, Sallie L.; Africano, John L.

1987-01-01

Light curves and period estimates were obtained for several Pleiades and Alpha Persei cluster K dwarfs which were identified as rapid rotators in earlier spectroscopic studies. A few of the stars have previously-published light curves, making it possible to study the long-term variability of the light-curve shapes. The general cause of the photometric variability observed for these stars is an asymmetric distribution of photospheric inhomogeneities (starspots). The presence of these inhomogeneities combined with the rotation of the star lead to the light curves observed. The photometric periods derived are thus identified with the rotation period of the star, making it possible to estimate equatorial rotational velocities for these K dwarfs. These data are of particular importance because the clusters are sufficiently young that stars of this mass should have just arrived on the main sequence. These data could be used to estimate the temperatures and sizes of the spot groups necessary to produce the observed light curves for these stars.

Global rotation

International Nuclear Information System (INIS)

Rosquist, K.

1980-01-01

Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

Rotation curves of galaxies by fourth order gravity

International Nuclear Information System (INIS)

Stabile, A.; Scelza, G.

2011-01-01

We investigate the radial behavior of galactic rotation curves by a Fourth Order Gravity adding also the dark matter component. The Fourth Order Gravity is a theory of gravity described by Lagrangian generalizing the one of Hilbert-Einstein containing a generic function of the Ricci scalar, the Ricci and Riemann tensor. A systematic analysis of rotation curves, in the Newtonian Limit of theory, induced by all galactic substructures of ordinary matter is shown. This analysis is presented for Fourth Order Gravity with and without dark matter. The outcomes are compared with respect to the classical outcomes of General Relativity. The gravitational potential of pointlike mass is the usual potential corrected by two Yukawa terms. The rotation curve is higher or also lower than curve of General Relativity if in the Lagrangian the Ricci scalar square is dominant or not with respect to the contribution of the Ricci tensor square. The theoretical spatial behaviors of rotation curve are compared with the experimental data for the Milky Way and the galaxy NGC 3198. Although the Fourth Order Gravity gives more rotational contributions, in the limit of large distances the Keplerian behavior is ever present, and it is missing only if we add the dark matter component. However by modifying the theory of gravity, consequently, also the spatial description of dark matter could undergo a modification and the free parameters of model can assume different values. After an analytical discussion of theoretical behaviors and the comparing with experimental evidence we can claim that any Fourth Order Gravity is not successful to explain the galactic rotation curves. In the last part of paper we analyze the gravitational potential induced by Lagrangian containing only powers of Ricci scalar. In this case we find an inconsistency in the boundary conditions in the passage from matter to the vacuum.

Flat rotation curves using scalar-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Cervantes-Cota, Jorge L [Depto de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 D.F. (Mexico); RodrIguez-Meza, M A [Depto de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 D.F. (Mexico); Nunez, Dario [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 D.F. (Mexico)

2007-11-15

We computed flat rotation curves from scalar-tensor theories in their weak field limit. Our model, by construction, fits a flat rotation profile for velocities of stars. As a result, the form of the scalar field potential and DM distribution in a galaxy are determined. By taking into account the constraints for the fundamental parameters of the theory ({lambda}, {alpha}), it is possible to obtain analytical results for the density profiles. For positive and negative values of {alpha}, the DM matter profile is as cuspy as NFW's.

Rotational damping motion in nuclei

International Nuclear Information System (INIS)

Egido, J.L.; Faessler, A.

1991-01-01

The recently proposed model to explain the mechanism of the rotational motion damping in nuclei is exactly solved. When compared with the earlier approximative solution, we find significative differences in the low excitation energy limit (i.e. Γ μ 0 ). For the strength functions we find distributions going from the Wigner semicircle through gaussians to Breit-Wigner shapes. (orig.)

At the Limits of Criticality-Based Quantum Metrology: Apparent Super-Heisenberg Scaling Revisited

Science.gov (United States)

Rams, Marek M.; Sierant, Piotr; Dutta, Omyoti; Horodecki, Paweł; Zakrzewski, Jakub

2018-04-01

We address the question of whether the super-Heisenberg scaling for quantum estimation is indeed realizable. We unify the results of two approaches. In the first one, the original system is compared with its copy rotated by the parameter-dependent dynamics. If the parameter is coupled to the one-body part of the Hamiltonian, the precision of its estimation is known to scale at most as N-1 (Heisenberg scaling) in terms of the number of elementary subsystems used N . The second approach compares the overlap between the ground states of the parameter-dependent Hamiltonian in critical systems, often leading to an apparent super-Heisenberg scaling. However, we point out that if one takes into account the scaling of time needed to perform the necessary operations, i.e., ensuring adiabaticity of the evolution, the Heisenberg limit given by the rotation scenario is recovered. We illustrate the general theory on a ferromagnetic Heisenberg spin chain example and show that it exhibits such super-Heisenberg scaling of ground-state fidelity around the critical value of the parameter (magnetic field) governing the one-body part of the Hamiltonian. Even an elementary estimator represented by a single-site magnetization already outperforms the Heisenberg behavior providing the N-1.5 scaling. In this case, Fisher information sets the ultimate scaling as N-1.75, which can be saturated by measuring magnetization on all sites simultaneously. We discuss universal scaling predictions of the estimation precision offered by such observables, both at zero and finite temperatures, and support them with numerical simulations in the model. We provide an experimental proposal of realization of the considered model via mapping the system to ultracold bosons in a periodically shaken optical lattice. We explicitly derive that the Heisenberg limit is recovered when the time needed for preparation of quantum states involved is taken into account.

The limiting behavior of the estimated parameters in a misspecified random field regression model

DEFF Research Database (Denmark)

Dahl, Christian Møller; Qin, Yu

This paper examines the limiting properties of the estimated parameters in the random field regression model recently proposed by Hamilton (Econometrica, 2001). Though the model is parametric, it enjoys the flexibility of the nonparametric approach since it can approximate a large collection of n...

Real Time Estimation of the Calgary Floods Using Limited Remote Sensing Data

Directory of Open Access Journals (Sweden)

Emily Schnebele

2014-02-01

Full Text Available Every year, flood disasters are responsible for widespread destruction and loss of human life. Remote sensing data are capable of providing valuable, synoptic coverage of flood events but are not always available because of satellite revisit limitations, obstructions from cloud cover or vegetation canopy, or expense. In addition, knowledge of road accessibility is imperative during all phases of a flood event. In June 2013, the City of Calgary experienced sudden and extensive flooding but lacked comprehensive remote sensing coverage. Using this event as a case study, this work illustrates how data from non-authoritative sources are used to augment traditional data and methods to estimate flood extent and identify affected roads during a flood disaster. The application of these data, which may have varying resolutions and uncertainities, provide an estimation of flood extent when traditional data and methods are lacking or incomplete. When flooding occurs over multiple days, it is possible to construct an estimate of the advancement and recession of the flood event. Non-authoritative sources also provide flood information at the micro-level, which can be difficult to capture from remote sensing data; however, the distibution and quantity of data collected from these sources will affect the quality of the flood estimations.

Performance of the MACRO limited streamer tubes for estimates of muon energy

CERN Document Server

Giorgini, M

2002-01-01

The MACRO limited streamer tubes can be operated in drift mode by using the TDCs included in the QTP system. In this way a considerable improvement in the space resolution is obtained, allowing the analysis of muon tracks in terms of multiple scattering effects and the energy estimates of muons crossing the detector. We present the results of two dedicated tests, performed with the CERN PS-T9 and SPS-X7 beams, to provide a full check of the electronics and to exploit the feasibility of the analysis. Using a neural network, we are able to estimate the muon energies up to E/sub mu / approximately = 40 GeV. The test beam data provide then an absolute energy calibration, which allows to apply the method to the MACRO data. (5 refs).

Earthquake Protection of Existing Structures with Limited Seismic Joint: Base Isolation with Supplemental Damping versus Rotational Inertia

Directory of Open Access Journals (Sweden)

Dario De Domenico

2018-01-01

Full Text Available Existing civil engineering structures having strategic importance, such as hospitals, fire stations, and power plants, often do not comply with seismic standards in force today, as they were designed and built based on past structural guidelines. On the other hand, due to their special importance, structural integrity of such buildings is of vital importance during and after earthquakes, which puts demands on strategies for their seismic protection. In this regard, seismic base isolation has been widely employed; however, the existing limited seismic joint between adjacent buildings may hamper this application because of the large displacements concentrated at the isolation floor. In this paper, we compare two possible remedies: the former is to provide supplemental damping in conventional base isolation systems and the latter consists in a combination of base isolation with supplemental rotational inertia. For the second strategy, a mechanical device, called inerter, is arranged in series with spring and dashpot elements to form the so-called tuned-mass-damper-inerter (TMDI directly connected to an isolation floor. Several advantages of this second system as compared to the first one are outlined, especially with regard to the limitation of floor accelerations and interstory drifts, which may be an issue for nonstructural elements and equipment, in addition to disturbing occupants. Once the optimal design of the TMDI is established, possible implementation of this system into existing structures is discussed.

Estimated general population control limits for unitary agents in drinking water, milk, soil, and unprocessed food items

Energy Technology Data Exchange (ETDEWEB)

Watson, A.P.; Adams, J.D.; Cerar, R.J.; Hess, T.L.; Kistner, S.L.; Leffingwell, S.S.; MacIntosh, R.G.; Ward, J.R.

1992-01-01

In the event of an unplanned release of chemical agent during any stage of the Chemical Stockpile Disposal Program (CSDP), the potential exists for contamination of drinking water, forage crops, grains, garden produce, and livestock. Persistent agents such as VX or sulfur mustard pose the greatest human health concern for reentry. This White Paper has been prepared to provide technical bases for these decisions by developing working estimates of agent control limits in selected environmental media considered principal sources of potential human exposure. To date, control limits for public exposure to unitary agents have been established for atmospheric concentrations only. The current analysis builds on previous work to calculate working estimates of control limits for ingestion and dermal exposure to potentially contaminated drinking water, milk, soil, and unprocessed food items such as garden produce. Information characterizing agent desorption from, and detection on or in, contaminated porous media are presently too developed to permit reasonable estimation of dermal exposure from this source. Thus, dermal contact with potentially contaminated porous surfaces is not considered in this document.

ROTATION AND MAGNETIC ACTIVITY IN A SAMPLE OF M-DWARFS

International Nuclear Information System (INIS)

Browning, Matthew K.; Basri, Gibor; Marcy, Geoffrey W.; Zhang Jiahao; West, Andrew A.

2010-01-01

We have analyzed the rotational broadening and chromospheric activity in a sample of 123 M-dwarfs, using spectra taken at the W.M. Keck Observatory as part of the California Planet Search program. We find that only seven of these stars are rotating more rapidly than our detection threshold of v sin i ∼ 2.5 km s -1 . Rotation appears to be more common in stars later than M3 than in the M0-M2.5 mass range: we estimate that less than 10% of early-M stars are detectably rotating, whereas roughly a third of those later than M4 show signs of rotation. These findings lend support to the view that rotational braking becomes less effective in fully convective stars. By measuring the equivalent widths of the Ca II H and K lines for the stars in our sample, and converting these to approximate L Ca /L bol measurements, we also provide constraints on the connection between rotation and magnetic activity. Measurable rotation is a sufficient, but not necessary condition for activity in our sample: all the detectable rotators show strong Ca II emission, but so too do a small number of non-rotating stars, which we presume may lie at high inclination angles relative to our line of sight. Our data are consistent with a 'saturation-type' rotation-activity relationship, with activity roughly independent of rotation above a threshold velocity of less than 6 km s -1 . We also find weak evidence for a 'gap' in L Ca /L bol between a highly active population of stars, which typically are detected as rotators, and another much less active group.

Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple

International Nuclear Information System (INIS)

Fetterman, Abraham J.; Fisch, Nathaniel J.

2011-01-01

Superthermal ExB rotation can provide magnetohydrodynamic (MHD) stability and enhanced confinement to axisymmetric mirrors. However, the rotation speed has been limited by phenomena at end electrodes. A new prediction is that rotation might instead be produced using a magnetic ripple and alpha particle kinetic energy, in an extension of the alpha channeling concept. The interaction of alpha particles with the ripple results in visually interesting and practically useful orbits.

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

Reconstruction of limited-angle dual-energy CT using mutual learning and cross-estimation (MLCE)

Science.gov (United States)

Zhang, Huayu; Xing, Yuxiang

2016-03-01

Dual-energy CT (DECT) imaging has gained a lot of attenuation because of its capability to discriminate materials. We proposes a flexible DECT scan strategy which can be realized on a system with general X-ray sources and detectors. In order to lower dose and scanning time, our DECT acquires two projections data sets on two arcs of limited-angular coverage (one for each energy) respectively. Meanwhile, a certain number of rays from two data sets form conjugate sampling pairs. Our reconstruction method for such a DECT scan mainly tackles the consequent limited-angle problem. Using the idea of artificial neural network, we excavate the connection between projections at two different energies by constructing a relationship between the linear attenuation coefficient of the high energy and that of the low one. We use this relationship to cross-estimate missing projections and reconstruct attenuation images from an augmented data set including projections at views covered by itself (projections collected in scanning) and by the other energy (projections estimated) for each energy respectively. Validated by our numerical experiment on a dental phantom with rather complex structures, our DECT is effective in recovering small structures in severe limited-angle situations. This DECT scanning strategy can much broaden DECT design in reality.

Impacts of Rotation Schemes on Ground-Dwelling Beneficial Arthropods.

Science.gov (United States)

Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

2016-10-01

Crop rotation alters agroecosystem diversity temporally, and increasing the number of crops in rotation schemes can increase crop yields and reduce reliance on pesticides. We hypothesized that increasing the number of crops in annual rotation schemes would positively affect ground-dwelling beneficial arthropod communities. During 2012 and 2013, pitfall traps were used to measure activity-density and diversity of ground-dwelling communities within three previously established, long-term crop rotation studies located in Wisconsin and Illinois. Rotation schemes sampled included continuous corn, a 2-yr annual rotation of corn and soybean, and a 3-yr annual rotation of corn, soybean, and wheat. Insects captured were identified to family, and non-insect arthropods were identified to class, order, or family, depending upon the taxa. Beneficial arthropods captured included natural enemies, granivores, and detritivores. The beneficial community from continuous corn plots was significantly more diverse compared with the community in the 2-yr rotation, whereas the community in the 3-yr rotation did not differ from either rotation scheme. The activity-density of the total community and any individual taxa did not differ among rotation schemes in either corn or soybean. Crop species within all three rotation schemes were annual crops, and are associated with agricultural practices that make infield habitat subject to anthropogenic disturbances and temporally unstable. Habitat instability and disturbance can limit the effectiveness and retention of beneficial arthropods, including natural enemies, granivores, and detritivores. Increasing non-crop and perennial species within landscapes in conjunction with more diverse rotation schemes may increase the effect of biological control of pests by natural enemies. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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.

Weak rotating flow disturbances in a centrifugal compressor with a vaneless diffuser

Science.gov (United States)

Moore, F. K.

1988-01-01

A theory is presented to predict the occurrence of weak rotating waves in a centrifugal compression system with a vaneless diffuser. As in a previous study of axial systems, an undisturbed performance characteristic is assumed known. Following an inviscid analysis of the diffuser flow, conditions for a neutral rotating disturbance are found. The solution is shown to have two branches; one with fast rotation, the other with very slow rotation. The slow branch includes a dense set of resonant solutions. The resonance is a feature of the diffuser flow, and therefore such disturbances must be expected at the various resonant flow coefficients regardless of the compressor characteristic. Slow solutions seem limited to flow coefficients less than about 0.3, where third and fourth harmonics appear. Fast waves seem limited to a first harmonic. These fast and slow waves are described, and effects of diffuser-wall convergence, backward blade angles, and partial recovery of exit velocity head are assessed.

Estimating Wear Of Installed Ball Bearings

Science.gov (United States)

Keba, John E.; Mcvey, Scott E.

1993-01-01

Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

Advancing development of a limit reference point estimator for sea turtles, and evaluating methods for applying local management to highly migratory species

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC is developing tools for estimation of limit reference points for marine turtles. These tools are being applied initially to estimate a limit reference point...

Advances in Molecular Rotational Spectroscopy for Applied Science

Science.gov (United States)

Harris, Brent; Fields, Shelby S.; Pulliam, Robin; Muckle, Matt; Neill, Justin L.

2017-06-01

Advances in chemical sensitivity and robust, solid-state designs for microwave/millimeter-wave instrumentation compel the expansion of molecular rotational spectroscopy as research tool into applied science. It is familiar to consider molecular rotational spectroscopy for air analysis. Those techniques for molecular rotational spectroscopy are included in our presentation of a more broad application space for materials analysis using Fourier Transform Molecular Rotational Resonance (FT-MRR) spectrometers. There are potentially transformative advantages for direct gas analysis of complex mixtures, determination of unknown evolved gases with parts per trillion detection limits in solid materials, and unambiguous chiral determination. The introduction of FT-MRR as an alternative detection principle for analytical chemistry has created a ripe research space for the development of new analytical methods and sampling equipment to fully enable FT-MRR. We present the current state of purpose-built FT-MRR instrumentation and the latest application measurements that make use of new sampling methods.

Faraday Rotation for SMOS Retrievals of Ocean Salinity and Soil Moisture

Science.gov (United States)

El-Nimri, Salem; Le Vine, David M.

2016-01-01

Faraday rotation is a change in polarization as radiation propagates from the surface through the ionosphere to the sensor. At L-band (1.4 GHz) this change can be significant and can be important for the remote sensing of soil moisture and ocean salinity from space. Consequently, modern L-band radiometers (SMOS, Aquarius and SMOS) are polarimetric to measure Faraday rotation in situ so that a correction can be made. This is done using the ratio of the third and second Stokes parameters. In the case of SMOS this procedure has produced very noisy estimates. An alternate procedure is reported here in which the total electron content is estimated and averaged to reduce noise.

Teaching and Learning in an 80-Hour Work Week: A Novel Day-float Rotation for Medical Residents

OpenAIRE

Wong, Jeffrey G; Holmboe, Eric S; Huot, Stephen J

2004-01-01

The 80-hour workweek limit for residents provides an opportunity for residency directors to creatively innovate their programs. Our novel day-float rotation augmented both the educational structure within the inpatient team setting and the ability for house staff to complete their work within the mandated limits. Descriptive evaluation of the rotation was performed through an end-of-rotation questionnaire. The average length of the ward residents’ work week was quantified before and after the...

Energy crops in rotation. A review

Energy Technology Data Exchange (ETDEWEB)

Zegada-Lizarazu, Walter; Monti, Andrea [Department of Agroenvironmental Science and Technology, University of Bologna, Viale G. Fanin, 44 - 40127, Bologna (Italy)

2011-01-15

The area under energy crops has increased tenfold over the last 10 years, and there is large consensus that the demand for energy crops will further increase rapidly to cover several millions of hectares in the near future. Information about rotational systems and effects of energy crops should be therefore given top priority. Literature is poor and fragmentary on this topic, especially about rotations in which all crops are exclusively dedicated to energy end uses. Well-planned crop rotations, as compared to continuous monoculture systems, can be expected to reduce the dependence on external inputs through promoting nutrient cycling efficiency, effective use of natural resources, especially water, maintenance of the long-term productivity of the land, control of diseases and pests, and consequently increasing crop yields and sustainability of production systems. The result of all these advantages is widely known as crop sequencing effect, which is due to the additional and positive consequences on soil physical-chemical and biological properties arising from specific crops grown in the same field year after year. In this context, the present review discusses the potential of several rotations with energy crops and their possibilities of being included alongside traditional agriculture systems across different agro-climatic zones within the European Union. Possible rotations dedicated exclusively to the production of biomass for bioenergy are also discussed, as rotations including only energy crops could become common around bio-refineries or power plants. Such rotations, however, show some limitations related to the control of diseases and to the narrow range of available species with high production potential that could be included in a rotation of such characteristics. The information on best-known energy crops such as rapeseed (Brassica napus) and sunflower (Helianthus annuus) suggests that conventional crops can benefit from the introduction of energy crops in

Earth rotation excitation mechanisms derived from geodetic space observations

Science.gov (United States)

Göttl, F.; Schmidt, M.

2009-04-01

Earth rotation variations are caused by mass displacements and motions in the subsystems of the Earth. Via the satellite Gravity and Climate Experiment (GRACE) gravity field variations can be identified which are caused by mass redistribution in the Earth system. Therefore time variable gravity field models (GFZ RL04, CSR RL04, JPL RL04, ITG-Grace03, GRGS, ...) can be used to derive different impacts on Earth rotation. Furthermore satellite altimetry provides accurate information on sea level anomalies (AVISO, DGFI) which are caused by mass and volume changes of seawater. Since Earth rotation is solely affected by mass variations and motions the volume (steric) effect has to be reduced from the altimetric observations in order to infer oceanic contributions to Earth rotation variations. Therefore the steric effect is estimated from physical ocean parameters such as temperature and salinity changes in the oceans (WOA05, Ishii). In this study specific individual geophysical contributions to Earth rotation variations are identified by means of a multitude of accurate geodetic space observations in combination with a realistic error propagation. It will be shown that due to adjustment of altimetric and/or gravimetric solutions the results for polar motion excitations can be improved.

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.

Inversion of ground-motion data from a seismometer array for rotation using a modification of Jaeger's method

Science.gov (United States)

Chi, Wu-Cheng; Lee, W.H.K.; Aston, J.A.D.; Lin, C.J.; Liu, C.-C.

2011-01-01

We develop a new way to invert 2D translational waveforms using Jaeger's (1969) formula to derive rotational ground motions about one axis and estimate the errors in them using techniques from statistical multivariate analysis. This procedure can be used to derive rotational ground motions and strains using arrayed translational data, thus providing an efficient way to calibrate the performance of rotational sensors. This approach does not require a priori information about the noise level of the translational data and elastic properties of the media. This new procedure also provides estimates of the standard deviations of the derived rotations and strains. In this study, we validated this code using synthetic translational waveforms from a seismic array. The results after the inversion of the synthetics for rotations were almost identical with the results derived using a well-tested inversion procedure by Spudich and Fletcher (2009). This new 2D procedure can be applied three times to obtain the full, three-component rotations. Additional modifications can be implemented to the code in the future to study different features of the rotational ground motions and strains induced by the passage of seismic waves.

A microelectrostatic repulsive-torque rotation actuator with two-width fingers

International Nuclear Information System (INIS)

Fan, Chao; He, Siyuan

2015-01-01

A microelectrostatic repulsive-torque rotation actuator with two-width fingers is presented. The actuator consists of finger-shaped electrodes and is made of two thin film layers, i.e. one movable layer and one fixed layer. There are two types of finger electrodes, namely constant-width and two-width fingers. The two-width finger has a narrow lower segment and a wide top segment. The constant-width finger has only the narrow lower segment. Each rotation finger has its corresponding aligned and unaligned fixed fingers. The electrostatic repulsive torque is generated and acts on the rotation fingers to rotate them up and away from the substrate. As a result, rotation is not limited by the gap between the movable and fixed layers and the ‘pull-in’ instability is avoided. Thus a large out-of-plane rotation and high operational stability can be achieved. The actuator is suitable for two-layer surface micromachining. The model of the actuator is developed. Prototypes are fabricated and tested. The experimental tests show that the actuator achieved a mechanical rotation of 7.65° at a driving voltage of 150 V. The settling time for a mechanical rotation of 5° is 5.7 ms. (paper)

Faraday rotation dispersion microscopy imaging of diamagnetic and chiral liquids with pulsed magnetic field.

Science.gov (United States)

Suwa, Masayori; Nakano, Yusuke; Tsukahara, Satoshi; Watarai, Hitoshi

2013-05-21

We have constructed an experimental setup for Faraday rotation dispersion imaging and demonstrated the performance of a novel imaging principle. By using a pulsed magnetic field and a polarized light synchronized to the magnetic field, quantitative Faraday rotation images of diamagnetic organic liquids in glass capillaries were observed. Nonaromatic hydrocarbons, benzene derivatives, and naphthalene derivatives were clearly distinguished by the Faraday rotation images due to the difference in Verdet constants. From the wavelength dispersion of the Faraday rotation images in the visible region, it was found that the resonance wavelength in the UV region, which was estimated based on the Faraday B-term, could be used as characteristic parameters for the imaging of the liquids. Furthermore, simultaneous acquisition of Faraday rotation image and natural optical rotation image was demonstrated for chiral organic liquids.

Dried blood spot measurement: application in tacrolimus monitoring using limited sampling strategy and abbreviated AUC estimation.

Science.gov (United States)

Cheung, Chi Yuen; van der Heijden, Jaques; Hoogtanders, Karin; Christiaans, Maarten; Liu, Yan Lun; Chan, Yiu Han; Choi, Koon Shing; van de Plas, Afke; Shek, Chi Chung; Chau, Ka Foon; Li, Chun Sang; van Hooff, Johannes; Stolk, Leo

2008-02-01

Dried blood spot (DBS) sampling and high-performance liquid chromatography tandem-mass spectrometry have been developed in monitoring tacrolimus levels. Our center favors the use of limited sampling strategy and abbreviated formula to estimate the area under concentration-time curve (AUC(0-12)). However, it is inconvenient for patients because they have to wait in the center for blood sampling. We investigated the application of DBS method in tacrolimus level monitoring using limited sampling strategy and abbreviated AUC estimation approach. Duplicate venous samples were obtained at each time point (C(0), C(2), and C(4)). To determine the stability of blood samples, one venous sample was sent to our laboratory immediately. The other duplicate venous samples, together with simultaneous fingerprick blood samples, were sent to the University of Maastricht in the Netherlands. Thirty six patients were recruited and 108 sets of blood samples were collected. There was a highly significant relationship between AUC(0-12), estimated from venous blood samples, and fingerprick blood samples (r(2) = 0.96, P AUC(0-12) strategy as drug monitoring.

Non-Cooperative Target Imaging and Parameter Estimation with Narrowband Radar Echoes

Directory of Open Access Journals (Sweden)

Chun-mao Yeh

2016-01-01

Full Text Available This study focuses on the rotating target imaging and parameter estimation with narrowband radar echoes, which is essential for radar target recognition. First, a two-dimensional (2D imaging model with narrowband echoes is established in this paper, and two images of the target are formed on the velocity-acceleration plane at two neighboring coherent processing intervals (CPIs. Then, the rotating velocity (RV is proposed to be estimated by utilizing the relationship between the positions of the scattering centers among two images. Finally, the target image is rescaled to the range-cross-range plane with the estimated rotational parameter. The validity of the proposed approach is confirmed using numerical simulations.

The circulation pattern and day-night heat transport in the atmosphere of a synchronously rotating aquaplanet: Dependence on planetary rotation rate

Science.gov (United States)

Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Takehiro, S.; Onishi, M.; Hashimoto, G. L.; Kuramoto, K.; Hayashi, Y.-Y.

2017-01-01

In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aquaplanet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-III to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the

Integrating national surveys to estimate small area variations in poor health and limiting long-term illness in Great Britain.

Science.gov (United States)

Moon, Graham; Aitken, Grant; Taylor, Joanna; Twigg, Liz

2017-08-28

This study aims to address, for the first time, the challenges of constructing small area estimates of health status using linked national surveys. The study also seeks to assess the concordance of these small area estimates with data from national censuses. Population level health status in England, Scotland and Wales. A linked integrated dataset of 23 374 survey respondents (16+ years) from the 2011 waves of the Health Survey for England (n=8603), the Scottish Health Survey (n=7537) and the Welsh Health Survey (n=7234). Population prevalence of poorer self-rated health and limiting long-term illness. A multilevel small area estimation modelling approach was used to estimate prevalence of these outcomes for middle super output areas in England and Wales and intermediate zones in Scotland. The estimates were then compared with matched measures from the contemporaneous 2011 UK Census. There was a strong positive association between the small area estimates and matched census measures for all three countries for both poorer self-rated health (r=0.828, 95% CI 0.821 to 0.834) and limiting long-term illness (r=0.831, 95% CI 0.824 to 0.837), although systematic differences were evident, and small area estimation tended to indicate higher prevalences than census data. Despite strong concordance, variations in the small area prevalences of poorer self-rated health and limiting long-term illness evident in census data cannot be replicated perfectly using small area estimation with linked national surveys. This reflects a lack of harmonisation between surveys over question wording and design. The nature of small area estimates as 'expected values' also needs to be better understood. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Unified approach to the entropy of an extremal rotating BTZ black hole: Thin shells and horizon limits

Science.gov (United States)

Lemos, José P. S.; Minamitsuji, Masato; Zaslavskii, Oleg B.

2017-10-01

Using a thin shell, the first law of thermodynamics, and a unified approach, we study the thermodymanics and find the entropy of a (2 +1 )-dimensional extremal rotating Bañados-Teitelbom-Zanelli (BTZ) black hole. The shell in (2 +1 ) dimensions, i.e., a ring, is taken to be circularly symmetric and rotating, with the inner region being a ground state of the anti-de Sitter spacetime and the outer region being the rotating BTZ spacetime. The extremal BTZ rotating black hole can be obtained in three different ways depending on the way the shell approaches its own gravitational or horizon radius. These ways are explicitly worked out. The resulting three cases give that the BTZ black hole entropy is either the Bekenstein-Hawking entropy, S =A/+ 4 G , or an arbitrary function of A+, S =S (A+) , where A+=2 π r+ is the area, i.e., the perimeter, of the event horizon in (2 +1 ) dimensions. We speculate that the entropy of an extremal black hole should obey 0 ≤S (A+)≤A/+ 4 G . We also show that the contributions from the various thermodynamic quantities, namely, the mass, the circular velocity, and the temperature, for the entropy in all three cases are distinct. This study complements the previous studies in thin shell thermodynamics and entropy for BTZ black holes. It also corroborates the results found for a (3 +1 )-dimensional extremal electrically charged Reissner-Nordström black hole.

Actinide solubility in deep groundwaters - estimates for upper limits based on chemical equilibrium calculations

International Nuclear Information System (INIS)

Schweingruber, M.

1983-12-01

A chemical equilibrium model is used to estimate maximum upper concentration limits for some actinides (Th, U, Np, Pu, Am) in groundwaters. Eh/pH diagrams for solubility isopleths, dominant dissolved species and limiting solids are constructed for fixed parameter sets including temperature, thermodynamic database, ionic strength and total concentrations of most important inorganic ligands (carbonate, fluoride, phosphate, sulphate, chloride). In order to assess conservative conditions, a reference water is defined with high ligand content and ionic strength, but without competing cations. In addition, actinide oxides and hydroxides are the only solid phases considered. Recommendations for 'safe' upper actinide solubility limits for deep groundwaters are derived from such diagrams, based on the predicted Eh/pH domain. The model results are validated as far as the scarce experimental data permit. (Auth.)

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

Science.gov (United States)

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

2015-12-01

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

[A Model for Predicting Career Satisfaction of Nurses Experiencing Rotation].

Science.gov (United States)

Shin, Sook; Yu, Mi

2017-08-01

This study aimed to present and test a structural model for describing and predicting the factors affecting subjective career satisfaction of nurses experiencing rotation and to develop human resources management strategies for promoting their career satisfaction related to rotation. In this cross-sectional study, we recruited 233 nurses by convenience sampling who had over 1 year of career experience and who had experienced rotation at least once at G university hospital. Data were collected from August to September in 2016 using self-reported questionnaires. The exogenous variables consisted of rotation perception and rotation stress. Endogenous variables consisted of career growth opportunity, work engagement, and subjective career satisfaction. A hypothetical model was tested by asymptotically distribution-free estimates, and model goodness of fit was examined using absolute fit, incremental fit measures. The final model was approved and had suitable fit. We found that subjective career satisfaction was directly affected by rotation stress (β=.20, p=.019) and work engagement (β=.58, pcareer growth opportunity and work engagement. However, there was no total effect of rotation stress on subjective career satisfaction (β=-.09, p=.270). Career growth opportunity directly and indirectly affected subjective career satisfaction (β=.29, pcareer satisfaction. The results of this study suggest that it is necessary to establish systematic and planned criteria for rotation so that nurses can grow and develop through sustained work and become satisfied with their career. © 2017 Korean Society of Nursing Science

Analytical Solution for the Anisotropic Rabi Model: Effects of Counter-Rotating Terms

Science.gov (United States)

Zhang, Guofeng; Zhu, Hanjie

2015-03-01

The anisotropic Rabi model, which was proposed recently, differs from the original Rabi model: the rotating and counter-rotating terms are governed by two different coupling constants. This feature allows us to vary the counter-rotating interaction independently and explore the effects of it on some quantum properties. In this paper, we eliminate the counter-rotating terms approximately and obtain the analytical energy spectrums and wavefunctions. These analytical results agree well with the numerical calculations in a wide range of the parameters including the ultrastrong coupling regime. In the weak counter-rotating coupling limit we find out that the counter-rotating terms can be considered as the shifts to the parameters of the Jaynes-Cummings model. This modification shows the validness of the rotating-wave approximation on the assumption of near-resonance and relatively weak coupling. Moreover, the analytical expressions of several physics quantities are also derived, and the results show the break-down of the U(1)-symmetry and the deviation from the Jaynes-Cummings model.

An Energy-Based Limit State Function for Estimation of Structural Reliability in Shock Environments

Directory of Open Access Journals (Sweden)

Michael A. Guthrie

2013-01-01

Full Text Available limit state function is developed for the estimation of structural reliability in shock environments. This limit state function uses peak modal strain energies to characterize environmental severity and modal strain energies at failure to characterize the structural capacity. The Hasofer-Lind reliability index is briefly reviewed and its computation for the energy-based limit state function is discussed. Applications to two degree of freedom mass-spring systems and to a simple finite element model are considered. For these examples, computation of the reliability index requires little effort beyond a modal analysis, but still accounts for relevant uncertainties in both the structure and environment. For both examples, the reliability index is observed to agree well with the results of Monte Carlo analysis. In situations where fast, qualitative comparison of several candidate designs is required, the reliability index based on the proposed limit state function provides an attractive metric which can be used to compare and control reliability.

WE-H-207A-09: Theoretical Limits to Molecular Biomarker Detection Using Magnetic Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Weaver, J [Dartmouth-Hitchcock Medical Center, Lebanon, NH (United States); Geisel School of Medicine, Dartmouth College, Hanover, NH (United States)

2016-06-15

Purpose: Estimate the limits of molecular biomarker detection using magnetic nanoparticle methods like in vivo ELISA. Methods: Magnetic nanoparticles in an alternating magnetic field produce a magnetization that can be detected at exceedingly low levels because the signal at the harmonic frequencies is uniquely produced by the nanoparticles. Because the magnetization can also be used to characterize the nanoparticle rotational freedom, the bound state can be found. If the nanoparticles are coated with molecules that bind the desired biomarker, the rotational freedom reflects the biomarker concentration. The irreducible noise limit is the thermal noise or Johnson noise of the tissue and the contrast that can be measured must be larger than that limit. The contrast produced is a function of the applied field and depends strongly on nanoparticle volume. We have estimated the contrast using a Langevin function of a single composite variable to approximate the full stochastic Langevin equation for nanoparticle dynamics. Results: The thermal noise for a bandwidth reasonable for spectroscopy suggests mid zeptomolar (10–21) to low attomolar (10–18) concentrations can be measured in a volume that is 10cm in scale. The suggested sensitivity is far below the physiologically concentrations of almost all critical biomarkers including cytokines (picomolar), hormones (nanomolar) and heat shock proteins. Conclusion: The sensitivity of in vivo ELISA concentration measurements should be sufficient to measure physiological concentrations of critical biomarkers like cytokines in vivo. Further the sensitivity should be sufficient to measure concentrations of other biomarkers that are six to eight orders of magnitude lower in concentration than immune signaling molecules like cytokines. NIH - 1U54CA151662-01 Department of Radiology.

Vibration-rotation band intensities in the IR spectra of polyatomic molecules

International Nuclear Information System (INIS)

El'kin, M.D.; Kosterina, E.K.; Berezin

1995-01-01

Using the curvilinear vibrational coordinates for a nuclear subsystem, expressions for the effective dipole-moment operators are derived in order to analyze the vibrational-rotational transitions in the IR spectra of polyatomic rigid molecules. The explicit expressions obtained for the intensities of hot bands allow one to estimate the influence of the vibration-rotation interaction within the framework of the adopted molecular-vibration model. The suggested method is shown to be suitable for Raman spectra analysis. 12 refs

The Influence of Pseudo Auditor Rotation on Audit Quality: New Evidence

Directory of Open Access Journals (Sweden)

Rahmat Febrianto

2017-12-01

Full Text Available The objectives of this research are twofold, to test the audit quality of companies that change their auditors either voluntarily or mandatorily and to test the financial characteristics as a factor for an accounting firm to engage in pseudo mandatory rotation. Since 2002, Indonesia has had legislation mandating companies to rotate their auditor after six years of consecutive engagements (five years prior to 2008. However, auditors sometimes seem to find their own way to deceive the mandatory regulation by a tactic called “pseudo” mandatory rotation. Thus, we divide mandatory rotation into two categories, pure and pseudo mandatory rotation. The results of the data we collected since the Ministerial decree became effective in 2003 indicate companies that rotate their auditors mandatorily have higher audit quality than that of companies voluntarily rotating auditors. However, we cannot find evidence that pseudo and pure mandatory rotation have different audit qualities. The results also indicate that switching among bigger accounting firms have the highest audit quality rather than switching between smaller audit firms which have lower audit quality. Lastly, the motives of an accounting firm to engage in pseudo or pure mandatory rotation are related to the financial size of their clients. Future research must consider the limitation stated in this study.

Effective charge versus bare charge: an analytical estimate for colloids in the infinite dilution limit

International Nuclear Information System (INIS)

Aubouy, Miguel; Trizac, Emmanuel; Bocquet, Lyderic

2003-01-01

We propose an analytical approximation for the dependence of the effective charge on the bare charge for spherical and cylindrical macro-ions as a function of the size of the colloid and salt content, for the situation of a unique colloid immersed in a sea of electrolyte (where the definition of an effective charge is non-ambiguous). Our approach is based on the Poisson-Boltzmann (PB) mean-field theory. Mathematically speaking, our estimate is asymptotically exact in the limit κa >> 1, where a is the radius of the colloid and κ is the inverse screening length. In practice, a careful comparison with effective charge parameters, obtained by numerically solving the full nonlinear PB theory, proves that our estimate is good down to κa ∼ 1. This is precisely the limit appropriate to treat colloidal suspensions. A particular emphasis is put on the range of parameters suitable to describe both single and double strand DNA molecules under physiological conditions

Rotational and spin viscosities of water: Application to nanofluidics

DEFF Research Database (Denmark)

Hansen, Jesper Søndergaard; Bruus, Henrik; Todd, B.D.

2010-01-01

In this paper we evaluate the rotational viscosity and the two spin viscosities for liquid water using equilibrium molecular dynamics. Water is modeled via the flexible SPC/Fw model where the Coulomb interactions are calculated via the Wolf method which enables the long simulation times required....... We find that the rotational viscosity is independent of the temperature in the range from 284 to 319 K. The two spin viscosities, on the other hand, decrease with increasing temperature and are found to be two orders of magnitude larger than that estimated by Bonthuis et al. [Phys. Rev. Lett. 103...

Rotation Period Determination for 5143 Heracles

Science.gov (United States)

Pilcher, Frederick; Briggs, John W.; Franco, Lorenzo; Inasaridze, Raguli Ya.; Krugly, Yurij N.; Molotiv, Igor E.; Klinglesmith, Daniel A., III; Pollock, Joe; Pravec, Petr

2012-07-01

The Earth crossing minor planet 5143 Heracles made in late 2011 its closest approach to Earth since discovery. A consortium of observers found a synodic rotation period near 2.706 hours and amplitude increasing from 0.08 ±0.02 magnitudes at phase angle 20 degrees to 0.18 ±0.03 magnitudes at phase angle 87 degrees, with 3 unequal maxima and minima per cycle. Magnitude parameters H = 14.10 ±0.04 and G = 0.08 ±0.02 are found, and the color index V-R = 0.42 ±0.07. For an asteroid of taxonomic class Q, a suggested albedo pv = 0.20 ±0.05 yields estimated diameter D = 4.5 ±0.7 km. Three possible binary events were recorded, but these are insufficient for binary detection to be secure. Retrograde rotation is suggested.

Effects of stimulus type and strategy on mental rotation network:an Activation Likelihood Estimation meta-analysis

Directory of Open Access Journals (Sweden)

Barbara eTomasino

2016-01-01

Full Text Available We could predict how an object would look like if we were to see it from different viewpoints. The brain network governing mental rotation (MR has been studied using a variety of stimuli and tasks instructions. By using activation likelihood estimation (ALE meta-analysis we tested whether different MR networks can be modulated by the type of stimulus (body vs. non body parts or by the type of tasks instructions (motor imagery-based vs. non-motor imagery-based MR instructions. Testing for the bodily and non-bodily stimulus axis revealed a bilateral sensorimotor activation for bodily-related as compared to non bodily-related stimuli and a posterior right lateralized activation for non bodily-related as compared to bodily-related stimuli. A top-down modulation of the network was exerted by the MR tasks instructions frame with a bilateral (preferentially sensorimotor left network for motor imagery- vs. non-motor imagery-based MR instructions and the latter activating a preferentially posterior right occipito-temporal-parietal network. The present quantitative meta-analysis summarizes and amends previous descriptions of the brain network related to MR and shows how it is modulated by top-down and bottom-up experimental factors.

Renormalization and Central limit theorem for critical dynamical systems with weak external noise

CERN Document Server

Diaz-Espinosa, O

2006-01-01

We study of the effect of weak noise on critical one dimensional maps; that is, maps with a renormalization theory. We establish a one dimensional central limit theorem for weak noises and obtain Berry--Esseen estimates for the rate of this convergence. We analyze in detail maps at the accumulation of period doubling and critical circle maps with golden mean rotation number. Using renormalization group methods, we derive scaling relations for several features of the effective noise after long times. We use these scaling relations to show that the central limit theorem for weak noise holds in both examples. We note that, for the results presented here, it is essential that the maps have parabolic behavior. They are false for hyperbolic orbits.

Rotator Cuff Repair in Adolescent Athletes.

Science.gov (United States)

Azzam, Michael G; Dugas, Jeffrey R; Andrews, James R; Goldstein, Samuel R; Emblom, Benton A; Cain, E Lyle

2018-04-01

Rotator cuff tears are rare injuries in adolescents but cause significant morbidity if unrecognized. Previous literature on rotator cuff repairs in adolescents is limited to small case series, with few data to guide treatment. Adolescent patients would have excellent functional outcome scores and return to the same level of sports participation after rotator cuff repair but would have some difficulty with returning to overhead sports. Case series; Level of evidence 4. A retrospective search of the practice's billing records identified all patients participating in at least 1 sport who underwent rotator cuff repair between 2006 and 2014 with an age Rotator Cuff Index. Thirty-two consecutive adolescent athletes (28 boys and 4 girls) with a mean age of 16.1 years (range, 13.2-17.9 years) met inclusion criteria. Twenty-nine patients (91%) had a traumatic event, and 27 of these patients (93%) had no symptoms before the trauma. The most common single tendon injury was to the supraspinatus (21 patients, 66%), of which 2 were complete tendon tears, 1 was a bony avulsion of the tendon, and 18 were high-grade partial tears. Fourteen patients (56%) underwent single-row repair of their rotator cuff tear, and 11 (44%) underwent double-row repair. All subscapularis injuries were repaired in open fashion, while all other tears were repaired arthroscopically. Twenty-seven patients (84%) completed the outcome questionnaires at a mean 6.2 years after surgery (range, 2-10 years). The mean ASES score was 93 (range, 65-100; SD = 9); mean Western Ontario Rotator Cuff Index, 89% (range, 60%-100%; SD = 13%); and mean numeric pain rating, 0.3 (range, 0-3; SD = 0.8). Overall, 25 patients (93%) returned to the same level of play or higher. Among overhead athletes, 13 (93%) were able to return to the same level of play, but 8 (57%) were forced to change positions. There were no surgical complications, but 2 patients did undergo a subsequent operation. Surgical repair of high-grade partial

KIC 9451096: Magnetic Activity, Flares and Differential Rotation

Science.gov (United States)

Özdarcan, O.; Yoldaş, E.; Dal, H. A.

2018-04-01

We present a spectroscopic and photometric analysis of KIC 9451096. The combined spectroscopic and photometric modelling shows that the system is a detached eclipsing binary in a circular orbit and composed of F5V + K2V components. Subtracting the best-fitting light curve model from the whole long cadence data reveals additional low (mmag) amplitude light variations in time and occasional flares, suggesting a low, but still remarkable level of magnetic spot activity on the K2V component. Analyzing the rotational modulation of the light curve residuals enables us to estimate the differential rotation coefficient of the K2V component as k = 0.069 ± 0.008, which is 3 times weaker compared with the solar value of k = 0.19, assuming a solar type differential rotation. We find the stellar flare activity frequency for the K2V component as 0.000368411 h-1 indicating a low magnetic activity level.

Rotating gravity currents. Part 1. Energy loss theory

Science.gov (United States)

Martin, J. R.; Lane-Serff, G. F.

2005-01-01

A comprehensive energy loss theory for gravity currents in rotating rectangular channels is presented. The model is an extension of the non-rotating energy loss theory of Benjamin (J. Fluid Mech. vol. 31, 1968, p. 209) and the steady-state dissipationless theory of rotating gravity currents of Hacker (PhD thesis, 1996). The theory assumes the fluid is inviscid, there is no shear within the current, and the Boussinesq approximation is made. Dissipation is introduced using a simple method. A head loss term is introduced into the Bernoulli equation and it is assumed that the energy loss is uniform across the stream. Conservation of momentum, volume flux and potential vorticity between upstream and downstream locations is then considered. By allowing for energy dissipation, results are obtained for channels of arbitrary depth and width (relative to the current). The results match those from earlier workers in the two limits of (i) zero rotation (but including dissipation) and (ii) zero dissipation (but including rotation). Three types of flow are identified as the effect of rotation increases, characterized in terms of the location of the outcropping interface between the gravity current and the ambient fluid on the channel boundaries. The parameters for transitions between these cases are quantified, as is the detailed behaviour of the flow in all cases. In particular, the speed of the current can be predicted for any given channel depth and width. As the channel depth increases, the predicted Froude number tends to surd 2, as for non-rotating flows.

Transverse mixing of ellipsoidal particles in a rotating drum

Directory of Open Access Journals (Sweden)

He Siyuan

2017-01-01

Full Text Available Rotating drums are widely used in industry for mixing, milling, coating and drying processes. In the past decades, mixing of granular materials in rotating drums has been extensively investigated, but most of the studies are based on spherical particles. Particle shape has an influence on the flow behaviour and thus mixing behaviour, though the shape effect has as-yet received limited study. In this work, discrete element method (DEM is employed to study the transverse mixing of ellipsoidal particles in a rotating drum. The effects of aspect ratio and rotating speed on mixing quality and mixing rate are investigated. The results show that mixing index increases exponentially with time for both spheres and ellipsoids. Particles with various aspect ratios are able to reach well-mixed states after sufficient revolutions in the rolling or cascading regime. Ellipsoids show higher mixing rate when rotational speed is set between 25 and 40 rpm. The relationship between mixing rate and aspect ratio of ellipsoids is established, demonstrating that, particles with aspect ratios of 0.5 and 2.0 achieve the highest mixing rates. Increasing rotating speed from 15 rpm to 40 rpm does not necessarily increase the mixing speed of spheres, while monotonous increase is observed for ellipsoids.

MaRGEE: Move and Rotate Google Earth Elements

Science.gov (United States)

Dordevic, Mladen M.; Whitmeyer, Steven J.

2015-12-01

Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

Doppler limited rotational transitions of OH and SH radicals measured by continuous-wave terahertz photomixing

Science.gov (United States)

Eliet, Sophie; Martin-Drumel, Marie-Aline; Guinet, Mickaël; Hindle, Francis; Mouret, Gaël; Bocquet, Robin; Cuisset, Arnaud

2011-12-01

A continuous-wave terahertz (CW-THz) source generated by photomixing has been employed to detect and quantify radicals produced in a cold plasma probing their spin-rotation transitions. Due to their dual interest for both atmospherists and astrophysicists, the hydroxyl OH and the mercapto SH radicals have been chosen. The photomixing technique which can access the largest range of THz frequencies of any known coherent source, allowed to resolve the Doppler-limited hyperfine transitions of OH in the 2.5 THz frequency region. Line profile analysis of the hyperfine components demonstrated that OH radicals have been detected in this region at a ppm level at a temperature close to 490 K. The hyperfine structure of SH has been resolved for the first time above 1 THz. Ten new frequency transitions have been measured in the 1.3-2.6 THz frequency range using the CW-THz synthesizer based on a frequency comb. With relative uncertainties better than 10 -7, the CW-THz frequencies measured in this study are now competitive with those measured by other instruments such as frequency multiplication chains or FT-FIR spectrometers and are now capable to improve the predictions of the complete high-resolution spectra of these radicals collected in the atmospheric and astrophysical spectroscopic databases. versioncorrigeeAC 2011-07-18 17:32 2011 Arnaud Cuisset.

Experimental analysis of flow structure in contra-rotating axial flow pump designed with different rotational speed concept

Science.gov (United States)

Cao, Linlin; Watanabe, Satoshi; Imanishi, Toshiki; Yoshimura, Hiroaki; Furukawa, Akinori

2013-08-01

As a high specific speed pump, the contra-rotating axial flow pump distinguishes itself in a rear rotor rotating in the opposite direction of the front rotor, which remarkably contributes to the energy conversion, the reduction of the pump size, better hydraulic and cavitation performances. However, with two rotors rotating reversely, the significant interaction between blade rows was observed in our prototype contra-rotating rotors, which highly affected the pump performance compared with the conventional axial flow pumps. Consequently, a new type of rear rotor was designed by the rotational speed optimization methodology with some additional considerations, aiming at better cavitation performance, the reduction of blade rows interaction and the secondary flow suppression. The new rear rotor showed a satisfactory performance at the design flow rate but an unfavorable positive slope of the head — flow rate curve in the partial flow rate range less than 40% of the design flow rate, which should be avoided for the reliability of pump-pipe systems. In the present research, to understand the internal flow field of new rear rotor and its relation to the performances at the partial flow rates, the velocity distributions at the inlets and outlets of the rotors are firstly investigated. Then, the boundary layer flows on rotor surfaces, which clearly reflect the secondary flow inside the rotors, are analyzed through the limiting streamline observations using the multi-color oil-film method. Finally, the unsteady numerical simulations are carried out to understand the complicated internal flow structures in the rotors.

Fatigue tests and life estimation of Incoloy alloy 908

International Nuclear Information System (INIS)

Feng, J.; Toma, L.S.; Jang, C.H.; Steeves, M.M.

1997-01-01

Incoloy reg-sign alloy 908* is a candidate conduit material for Nb 3 Sn cable-in-conduit superconductors. The conduit is expected to experience cyclic loads at 4 K. Fatigue fracture of the conduit is one possible failure mode. So far, fatigue life has been estimated from fatigue crack growth data, which provide conservative results. The more traditional practice of life estimation using S-N curves has not been done for alloy 908 due to a lack of data at room and cryogenic temperatures. This paper presents a series of fatigue test results in response to this need. Tests were performed in reversed bending, rotating bending, and uniaxial fatigue machines. The test matrix included different heat treatments, two load ratios (R=-1 and 0.1), two temperatures (298 and 77 K), and two orientations (longitudinal and transverse). As expected, there is a semi-log linear relation between the applied stress and fatigue life above an applied stress (e.g., 310 MPa for tests at 298 K and R=-1). Below this stress the curves show an endurance limit. The aged and cold-worked materials have longer fatigue lives and higher endurance limits than the others. Different orientations have no apparent effect on life. Cryogenic temperature results in a much high fatigue life than room temperature. A higher tensile mean stress gives shorter fatigue life. It was also found that the fatigue lives of the reversed bending specimens were of the same order as those of the uniaxial test specimens, but were only half the lives of the rotating bending specimens for given stresses. A sample application of the S-N data is discussed

Asteroid rotation rates

International Nuclear Information System (INIS)

Binzel, R.P.; Farinella, P.

1989-01-01

Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

Surgery or conservative treatment for rotator cuff tear: a meta-analysis.

Science.gov (United States)

Ryösä, Anssi; Laimi, Katri; Äärimaa, Ville; Lehtimäki, Kaisa; Kukkonen, Juha; Saltychev, Mikhail

2017-07-01

Comparative evidence on treating rotator cuff tear is inconclusive. The objective of this review was to evaluate the evidence on effectiveness of tendon repair in reducing pain and improving function of the shoulder when compared with conservative treatment of symptomatic rotator cuff tear. Search on CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science and Pedro databases. Randomised controlled trials (RCT) comparing surgery and conservative treatment of rotator cuff tear. Study selection and extraction based on the Cochrane Handbook for Systematic reviews of Interventions. Random effects meta-analysis. Three identified RCTs involved 252 participants (123 cases and 129 controls). The risk of bias was considered low for all three RCTs. For Constant score, statistically insignificant effect size was 5.6 (95% CI -0.41 to 11.62) points in 1-year follow up favouring surgery and below the level of minimal clinically important difference. The respective difference in pain reduction was -0.93 (95% CI -1.65 to -0.21) cm on a 0-10 pain visual analogue scale favouring surgery. The difference was statistically significant (p = 0.012) in 1-year follow up but below the level of minimal clinically important difference. There is limited evidence that surgery is not more effective in treating rotator cuff tear than conservative treatment alone. Thus, a conservative approach is advocated as the initial treatment modality. Implications for Rehabilitation There is limited evidence that surgery is not more effective in treating rotator cuff tear than conservative treatment alone. There was no clinically significant difference between surgery and active physiotherapy in 1-year follow-up in improving Constant score or reducing pain caused by rotator cuff tear. As physiotherapy is less proneness to complications and less expensive than surgery, a conservative approach is advocated as the initial treatment modality to rotator cuff tears.

A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections

International Nuclear Information System (INIS)

Zhang, You; Yin, Fang-Fang; Ren, Lei; Segars, W. Paul

2013-01-01

Purpose: To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy.Methods: Each phase of onboard 4D-CBCT is considered as a deformation from one selected phase (prior volume) of the planning 4D-CT. The deformation field maps (DFMs) are solved using a motion modeling and free-form deformation (MM-FD) technique. In the MM-FD technique, the DFMs are estimated using a motion model which is extracted from planning 4D-CT based on principal component analysis (PCA). The motion model parameters are optimized by matching the digitally reconstructed radiographs of the deformed volumes to the limited-angle onboard projections (data fidelity constraint). Afterward, the estimated DFMs are fine-tuned using a FD model based on data fidelity constraint and deformation energy minimization. The 4D digital extended-cardiac-torso phantom was used to evaluate the MM-FD technique. A lung patient with a 30 mm diameter lesion was simulated with various anatomical and respirational changes from planning 4D-CT to onboard volume, including changes of respiration amplitude, lesion size and lesion average-position, and phase shift between lesion and body respiratory cycle. The lesions were contoured in both the estimated and “ground-truth” onboard 4D-CBCT for comparison. 3D volume percentage-difference (VPD) and center-of-mass shift (COMS) were calculated to evaluate the estimation accuracy of three techniques: MM-FD, MM-only, and FD-only. Different onboard projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy.Results: For all simulated patient and projection acquisition scenarios, the mean VPD (±S.D.)/COMS (±S.D.) between lesions in prior images and “ground-truth” onboard images were 136.11% (±42.76%)/15.5 mm (±3.9 mm). Using orthogonal-view 15°-each scan angle, the mean VPD/COMS between the lesion

Does limited data availability prevent adequate water use estimates on farm scale?

Science.gov (United States)

Kayatz, Benjamin; Kuster, Benjamin; Percy, Barbara; Hillier, Jonathan; Freese, Dirk; Wattenbach, Martin

2015-04-01

Increasing food production for a growing world population and at the same time mitigating climate change as well as adapting to its consequences is one of the key global challenges. Therefore producing crops with fewer resources such as water and fertilizers and less emissions of greenhouse gases is an important question that has to be answered on farm scale. The cool farm tool (CFT) is a farm scale emission calculator and was developed in 2010 to help farmers to reduce their carbon footprint. In order to adapt to future climate change an easy to use and at the same time robust water footprinting tool is needed for the CFT to take a more holistic approach on environmental sustainability. However data on farm level is often scarce. We investigated the effect of limited data on actual evapotranspiration using the FAO56 standard to assess the quality of farm water footprint estimates. Calculations are based on various agricultural sites from the Fluxnet database and estimates are compared to eddy covariance measurements. Results show that higher data availability is not directly linked to more accurate estimates of actual evapotranspiration. Estimates based only on temperature and relative humidity are still able to reproduce daily patterns. However cumulative values over one growing season show a considerable offset to eddy covariance observations for all data input levels. Finding the optimum between data requirements and an accuracy that fulfills farmer needs is crucial. Engagement of farmers and using a global network as the Fluxnet database will help to achieve this goal.

The K2 M67 Study: Establishing the Limits of Stellar Rotation Period Measurements in M67 with K2 Campaign 5 Data

Science.gov (United States)

Esselstein, Rebecca; Aigrain, Suzanne; Vanderburg, Andrew; Smith, Jeffrey C.; Meibom, Soren; Van Saders, Jennifer; Mathieu, Robert

2018-06-01

The open cluster M67 offers a unique opportunity to measure rotation periods for solar-age stars across a range of masses, potentially filling a critical gap in the understanding of angular momentum loss in older main sequence stars. The observation of M67 by NASA K2 Campaign 5 provided light curves with high enough precision to make this task possible, albeit challenging, as the pointing instability, 75 day observation window, crowded field, and typically low-amplitude signals mean that determining accurate rotation periods on the order of 25–30 days is inherently difficult. Lingering, non-astrophysical signals with power at ≥25 days found in a set of Campaign 5 A and F stars compounds the problem. To achieve a quantitative understanding of the best-case scenario limits for reliable period detection imposed by these inconveniences, we embarked on a comprehensive set of injection tests, injecting 120,000 sinusoidal signals with periods ranging from 5 to 35 days and amplitudes from 0.05% to 3.0% into real Campaign 5 M67 light curves processed using two different pipelines. We attempted to recover the signals using a normalized version of the Lomb–Scargle periodogram and setting a detection threshold. We find that, while the reliability of detected periods is high, the completeness (sensitivity) drops rapidly with increasing period and decreasing amplitude, maxing at a 15% recovery rate for the solar case (i.e., 25 day period, 0.1% amplitude). This study highlights the need for caution in determining M67 rotation periods from Campaign 5 data, but this can be extended to other clusters observed by K2 (and soon, TESS).

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.

Shift, rotation and scale invariant optical information authentication with binary digital holography

Science.gov (United States)

Jiao, Shuming; Zhou, Changyuan; Zou, Wenbin; Li, Xia

2017-12-01

An optical information authentication system using binary holography is proposed recently, with high security, flexibility and reduced cipher-text size. Despite the success, we point out one limitation of this system that it cannot well verify scaled and rotated versions of correct images and simply regard them as wrong images. In fact, this limitation generally exists in many other optical authentication systems. In this paper, a preprocessing method based Fourier transform and log polar transform is employed to allow the optical authentication systems shift, rotation and scale invariant. Numerical simulation results demonstrate that our proposed scheme significantly outperforms the existing method.

Measurement and Analysis of Rotational Energy of Nitrogen Molecular Beam by REMPI

International Nuclear Information System (INIS)

Mori, H.; Yamaguchi, H.; Kataoka, K.; Sugiyama, N.; Ide, K.; Niimi, T.

2008-01-01

Molecular beams are powerful tools for diagnoses of solid surfaces and gas-surface interaction tests. Unfortunately, there are very few reports about experimental analysis of internal energy distribution (e.g. rotational energy) of molecular beams of diatomic or polyatomic molecules, because measurement of internal energy distribution is very difficult. Spectroscopic measurement techniques based on resonantly enhanced multiphoton ionization (REMPI) is very powerful for measurement in highly rarefied gas flows. In this study, the REMPI method is applied to measurement of rotational energy distribution of nitrogen molecular beams. The REMPI spectrum of the molecular beam indicates the rotational temperature higher than the translational temperature of 7.2 K estimated by assuming isentropic flows. The O and P branches of the REMPI spectrum correspond to the rotational temperature of 30 K, but the S branch of the spectrum deviates from that at 30 K. It seems to be because the non-equilibrium rotational energy distribution of the molecular beam deviates from the Boltzmann distribution.

Estimation of the limit of detection in semiconductor gas sensors through linearized calibration models.

Science.gov (United States)

Burgués, Javier; Jiménez-Soto, Juan Manuel; Marco, Santiago

2018-07-12

The limit of detection (LOD) is a key figure of merit in chemical sensing. However, the estimation of this figure of merit is hindered by the non-linear calibration curve characteristic of semiconductor gas sensor technologies such as, metal oxide (MOX), gasFETs or thermoelectric sensors. Additionally, chemical sensors suffer from cross-sensitivities and temporal stability problems. The application of the International Union of Pure and Applied Chemistry (IUPAC) recommendations for univariate LOD estimation in non-linear semiconductor gas sensors is not straightforward due to the strong statistical requirements of the IUPAC methodology (linearity, homoscedasticity, normality). Here, we propose a methodological approach to LOD estimation through linearized calibration models. As an example, the methodology is applied to the detection of low concentrations of carbon monoxide using MOX gas sensors in a scenario where the main source of error is the presence of uncontrolled levels of humidity. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

Improving slowness estimate stability and visualization using limited sensor pair correlation on seismic arrays

Science.gov (United States)

Gibbons, Steven J.; Näsholm, S. P.; Ruigrok, E.; Kværna, T.

2018-04-01

Seismic arrays enhance signal detection and parameter estimation by exploiting the time-delays between arriving signals on sensors at nearby locations. Parameter estimates can suffer due to both signal incoherence, with diminished waveform similarity between sensors, and aberration, with time-delays between coherent waveforms poorly represented by the wave-front model. Sensor-to-sensor correlation approaches to parameter estimation have an advantage over direct beamforming approaches in that individual sensor-pairs can be omitted without necessarily omitting entirely the data from each of the sensors involved. Specifically, we can omit correlations between sensors for which signal coherence in an optimal frequency band is anticipated to be poor or for which anomalous time-delays are anticipated. In practice, this usually means omitting correlations between more distant sensors. We present examples from International Monitoring System seismic arrays with poor parameter estimates resulting when classical f-k analysis is performed over the full array aperture. We demonstrate improved estimates and slowness grid displays using correlation beamforming restricted to correlations between sufficiently closely spaced sensors. This limited sensor-pair correlation (LSPC) approach has lower slowness resolution than would ideally be obtained by considering all sensor-pairs. However, this ideal estimate may be unattainable due to incoherence and/or aberration and the LSPC estimate can often exploit all channels, with the associated noise-suppression, while mitigating the complications arising from correlations between very distant sensors. The greatest need for the method is for short-period signals on large aperture arrays although we also demonstrate significant improvement for secondary regional phases on a small aperture array. LSPC can also provide a robust and flexible approach to parameter estimation on three-component seismic arrays.

Disability and satisfaction after Rotator Cuff decompression or repair: a sex and gender analysis

Directory of Open Access Journals (Sweden)

Davis Aileen M

2011-04-01

Full Text Available Abstract Background Rotator-cuff pathology is the most common cause of pain and disability in the shoulder. Examining the combined effect of biological and societal factors on disability would potentially identify existing differences between men and women with rotator cuff pathology which would help to provide suggestions for better models of care. Purpose of this study was to determine the overall differences in disability between men and women and to examine the relationship between factors that represent sex (biological factors and gender (non-biological factors with disability and satisfaction with surgical outcome 6 months after rotator cuff surgery. Methods Patients with impingement syndrome and/or rotator cuff tear who underwent rotator cuff surgery completed the Western Ontario Rotator Cuff (WORC index, the American Shoulder & Elbow Surgeons (ASES assessment form, and the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH outcome measures prior to surgery and 6 months post-operatively. They also rated their satisfaction with surgery at their follow-up appointment. Results and Discussion One hundred and seventy patients entered into the study (85 men and 85 women. One hundred and sixty patients (94% completed the 6-month assessment. Women reported more disability both prior to and after surgery. Disability at 6 months was associated with pain-limited range of motion, participation limitation, age and strength. Satisfaction with surgery was associated with level of reported disability, expectations for improved pain, pain-limited range of motion and strength. Conclusions The results of this study indicate that women with rotator cuff pathology suffer from higher levels of pre- and post-operative disability and sex and gender qualities contribute to these differences. Gender-sensitive approach will help to identify existing differences between men and women which will help to promote more effective and tailored care by health

SU-D-206-07: CBCT Scatter Correction Based On Rotating Collimator

International Nuclear Information System (INIS)

Yu, G; Feng, Z; Yin, Y; Qiang, L; Li, B; Huang, P; Li, D

2016-01-01

Purpose: Scatter correction in cone-beam computed tomography (CBCT) has obvious effect on the removal of image noise, the cup artifact and the increase of image contrast. Several methods using a beam blocker for the estimation and subtraction of scatter have been proposed. However, the inconvenience of mechanics and propensity to residual artifacts limited the further evolution of basic and clinical research. Here, we propose a rotating collimator-based approach, in conjunction with reconstruction based on a discrete Radon transform and Tchebichef moments algorithm, to correct scatter-induced artifacts. Methods: A rotating-collimator, comprising round tungsten alloy strips, was mounted on a linear actuator. The rotating-collimator is divided into 6 portions equally. The round strips space is evenly spaced on each portion but staggered between different portions. A step motor connected to the rotating collimator drove the blocker to around x-ray source during the CBCT acquisition. The CBCT reconstruction based on a discrete Radon transform and Tchebichef moments algorithm is performed. Experimental studies using water phantom and Catphan504 were carried out to evaluate the performance of the proposed scheme. Results: The proposed algorithm was tested on both the Monte Carlo simulation and actual experiments with the Catphan504 phantom. From the simulation result, the mean square error of the reconstruction error decreases from 16% to 1.18%, the cupping (τcup) from 14.005% to 0.66%, and the peak signal-to-noise ratio increase from 16.9594 to 31.45. From the actual experiments, the induced visual artifacts are significantly reduced. Conclusion: We conducted an experiment on CBCT imaging system with a rotating collimator to develop and optimize x-ray scatter control and reduction technique. The proposed method is attractive in applications where a high CBCT image quality is critical, for example, dose calculation in adaptive radiation therapy. We want to thank Dr. Lei

SU-D-206-07: CBCT Scatter Correction Based On Rotating Collimator

Energy Technology Data Exchange (ETDEWEB)

Yu, G; Feng, Z [Shandong Normal University, Jinan, Shandong (China); Yin, Y [Shandong Cancer Hospital and Institute, China, Jinan, Shandong (China); Qiang, L [Zhang Jiagang STFK Medical Device Co, Zhangjiangkang, Suzhou (China); Li, B [Shandong Academy of Medical Sciences, Jinan, Shandong provice (China); Huang, P [Shandong Province Key Laboratory of Medical Physics and Image Processing Te, Ji’nan, Shandong province (China); Li, D [School of Physics and Electronics, Shandong Normal University, Jinan, Shandong (China)

2016-06-15

Purpose: Scatter correction in cone-beam computed tomography (CBCT) has obvious effect on the removal of image noise, the cup artifact and the increase of image contrast. Several methods using a beam blocker for the estimation and subtraction of scatter have been proposed. However, the inconvenience of mechanics and propensity to residual artifacts limited the further evolution of basic and clinical research. Here, we propose a rotating collimator-based approach, in conjunction with reconstruction based on a discrete Radon transform and Tchebichef moments algorithm, to correct scatter-induced artifacts. Methods: A rotating-collimator, comprising round tungsten alloy strips, was mounted on a linear actuator. The rotating-collimator is divided into 6 portions equally. The round strips space is evenly spaced on each portion but staggered between different portions. A step motor connected to the rotating collimator drove the blocker to around x-ray source during the CBCT acquisition. The CBCT reconstruction based on a discrete Radon transform and Tchebichef moments algorithm is performed. Experimental studies using water phantom and Catphan504 were carried out to evaluate the performance of the proposed scheme. Results: The proposed algorithm was tested on both the Monte Carlo simulation and actual experiments with the Catphan504 phantom. From the simulation result, the mean square error of the reconstruction error decreases from 16% to 1.18%, the cupping (τcup) from 14.005% to 0.66%, and the peak signal-to-noise ratio increase from 16.9594 to 31.45. From the actual experiments, the induced visual artifacts are significantly reduced. Conclusion: We conducted an experiment on CBCT imaging system with a rotating collimator to develop and optimize x-ray scatter control and reduction technique. The proposed method is attractive in applications where a high CBCT image quality is critical, for example, dose calculation in adaptive radiation therapy. We want to thank Dr. Lei

Epidemiology, natural history, and indications for treatment of rotator cuff tears.

Science.gov (United States)

Tashjian, Robert Z

2012-10-01

The etiology of rotator cuff disease is likely multifactorial, including age-related degeneration and microtrauma and macrotrauma. The incidence of rotator cuff tears increases with aging with more than half of individuals in their 80s having a rotator cuff tear. Smoking, hypercholesterolemia, and genetics have all been shown to influence the development of rotator cuff tearing. Substantial full-thickness rotator cuff tears, in general, progress and enlarge with time. Pain, or worsening pain, usually signals tear progression in both asymptomatic and symptomatic tears and should warrant further investigation if the tear is treated conservatively. Larger (>1-1.5 cm) symptomatic full-thickness cuff tears have a high rate of tear progression and, therefore, should be considered for earlier surgical repair in younger patients if the tear is reparable and there is limited muscle degeneration to avoid irreversible changes to the cuff, including tear enlargement and degenerative muscle changes. Smaller symptomatic full-thickness tears have been shown to have a slower rate of progression, similar to partial-thickness tears, and can be considered for initial nonoperative treatment due to the limited risk for rapid tear progression. In both small full-thickness tears and partial-thickness tears, increasing pain should alert physicians to obtain further imaging as it can signal tear progression. Natural history data, along with information on factors affecting healing after rotator cuff repair, can help guide surgeons in making appropriate decisions regarding the treatment of rotator cuff tears. The management of rotator cuff tears should be considered in the context of the risks and benefits of operative versus nonoperative treatment. Tear size and acuity, the presence of irreparable changes to the rotator cuff or glenohumeral joint, and patient age should all be considered in making this decision. Initial nonoperative care can be safely undertaken in older patients (>70

Estimating the boundaries of a limit cycle in a 2D dynamical system using renormalization group

Science.gov (United States)

Dutta, Ayan; Das, Debapriya; Banerjee, Dhruba; Bhattacharjee, Jayanta K.

2018-04-01

While the plausibility of formation of limit cycle has been a well studied topic in context of the Poincare-Bendixson theorem, studies on estimates in regard to the possible size and shape of the limit cycle seem to be scanty in the literature. In this paper we present a pedagogical study of some aspects of the size of this limit cycle using perturbative renormalization group by doing detailed and explicit calculations upto second order for the Selkov model for glycolytic oscillations. This famous model is well known to lead to a limit cycle for certain ranges of values of the parameters involved in the problem. Within the tenets of the approximations made, reasonable agreement with the numerical plots can be achieved.

Rotator cuff exercises

Science.gov (United States)

... 25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder MRI scan Shoulder pain Patient Instructions Rotator cuff - self-care Shoulder surgery - discharge Using your ...

Residual life estimation of electrical insulation system for rotating equipment

International Nuclear Information System (INIS)

Vashishtha, Y.D.; Gupta, A.K.; Bhattacharyya, A.K.; Verma, A.K.

1994-01-01

Residual life assessment gains significance towards the end of designed life for granting plant life extensions and resource planning for costly equipment replacement. A critical review of all the diagnostic techniques presently used to assess either health of insulation system or to infer qualitatively the remaining life for rotating machines is presented. However more emphasis is required on developing quantitative methods. This paper also formulates the experimental plan for progressively censored ageing tests, measurement of partial discharge parameters, micro-structural study for delamination and electrical tree growth and measurement of electrical breakdown strength. Partial discharge (PD) patterns, electrical tree growth and time to failure data shall be taken as training set for the neural network learning which can be useful to predict residual life with only one candidate parameter i.e. PD patterns. (author). 9 refs

Phenotypic variance, plasticity and heritability estimates of critical thermal limits depend on methodological context

DEFF Research Database (Denmark)

Chown, Steven L.; Jumbam, Keafon R.; Sørensen, Jesper Givskov

2009-01-01

used during assessments of critical thermal limits to activity. To date, the focus of work has almost exclusively been on the effects of rate variation on mean values of the critical limits. 2.  If the rate of temperature change used in an experimental trial affects not only the trait mean but also its...... this is the case for critical thermal limits using a population of the model species Drosophila melanogaster and the invasive ant species Linepithema humile. 4.  We found that effects of the different rates of temperature change are variable among traits and species. However, in general, different rates...... of temperature change resulted in different phenotypic variances and different estimates of heritability, presuming that genetic variance remains constant. We also found that different rates resulted in different conclusions regarding the responses of the species to acclimation, especially in the case of L...

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.

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

On selection rules in vibrational and rotational molecular spectroscopy

International Nuclear Information System (INIS)

Guichardet, A.

1986-01-01

The aim of this work is a rigorous proof of the Selection Rules in Molecular Spectroscopy (Vibration and Rotation). To get this we give mathematically rigorous definitions of the (tensor) transition operators, in this case the electric dipole moment; this is done, firstly by considering the molecule as a set of point atomic kernels performing arbitrary motions, secondly by limiting ourselves either to infinitesimal vibration motions, or to arbitrary rotation motions. Then the selection rules follow from an abstract formulation of the Wigner-Eckart theorem. In a last paragraph we discuss the problem of separating vibration and rotation motions; very simple ideas from Differential Geometry, linked with the ''slice theorem'', allow us to define the relative speeds, the solid motions speeds, the Coriolis energies and the moving Eckart frames [fr

The tumbling rotational state of 1I/`Oumuamua

Science.gov (United States)

Fraser, Wesley C.; Pravec, Petr; Fitzsimmons, Alan; Lacerda, Pedro; Bannister, Michele T.; Snodgrass, Colin; Smolić, Igor

2018-05-01

The discovery1 of 1I/2017 U1 (1I/`Oumuamua) has provided the first glimpse of a planetesimal born in another planetary system. This interloper exhibits a variable colour within a range that is broadly consistent with local small bodies, such as the P- and D-type asteroids, Jupiter Trojans and dynamically excited Kuiper belt objects2-7. 1I/`Oumuamua appears unusually elongated in shape, with an axial ratio exceeding 5:1 (refs 1,4,5,8). Rotation period estimates are inconsistent and varied, with reported values between 6.9 and 8.3 h (refs 4-6,9). Here, we analyse all the available optical photometry data reported to date. No single rotation period can explain the exhibited brightness variations. Rather, 1I/`Oumuamua appears to be in an excited rotational state undergoing non-principal axis rotation, or tumbling. A satisfactory solution has apparent lightcurve frequencies of 0.135 and 0.126 h-1 and implies a longest-to-shortest axis ratio of ≳5:1, although the available data are insufficient to uniquely constrain the true frequencies and shape. Assuming a body that responds to non-principal axis rotation in a similar manner to Solar System asteroids and comets, the timescale to damp 1I/`Oumuamua's tumbling is at least one billion years. 1I/`Oumuamua was probably set tumbling within its parent planetary system and will remain tumbling well after it has left ours.

Research on Radar Micro-Doppler Feature Parameter Estimation of Propeller Aircraft

Science.gov (United States)

He, Zhihua; Tao, Feixiang; Duan, Jia; Luo, Jingsheng

2018-01-01

The micro-motion modulation effect of the rotated propellers to radar echo can be a steady feature for aircraft target recognition. Thus, micro-Doppler feature parameter estimation is a key to accurate target recognition. In this paper, the radar echo of rotated propellers is modelled and simulated. Based on which, the distribution characteristics of the micro-motion modulation energy in time, frequency and time-frequency domain are analyzed. The micro-motion modulation energy produced by the scattering points of rotating propellers is accumulated using the Inverse-Radon (I-Radon) transform, which can be used to accomplish the estimation of micro-modulation parameter. Finally, it is proved that the proposed parameter estimation method is effective with measured data. The micro-motion parameters of aircraft can be used as the features of radar target recognition.

Design and testing of a rotational brake with shear thickening fluids

Science.gov (United States)

Tian, Tongfei; Nakano, Masami

2017-03-01

A rotational brake working with shear thickening fluid (STF) was designed and tested in this study. With the optimisation in design, most of the STF in the brake can receive the same shear rate when the brake rotates. The parts of this brake were fabricated with a 3D printer and then assembled manually. Three types of STFs with various carrier fluids and different particles were fabricated and tested with a rheometer. Then the brake with each STF was separately tested with the rheometer. The estimated and measured torques as a function of the angular velocity fit each other well. The stability of the rotational STF brake was investigated in repeated tests, which proved the function of the brake for a long time.

Magneto-optical Faraday rotation of semiconductor nanoparticles embedded in dielectric matrices.

Science.gov (United States)

Savchuk, Andriy I; Stolyarchuk, Ihor D; Makoviy, Vitaliy V; Savchuk, Oleksandr A

2014-04-01

Faraday rotation has been studied for CdS, CdTe, and CdS:Mn semiconductor nanoparticles synthesized by colloidal chemistry methods. Additionally these materials were prepared in a form of semiconductor nanoparticles embedded in polyvinyl alcohol films. Transmission electron microscopy and atomic force microscopy analyses served as confirmation of nanocrystallinity and estimation of the average size of the nanoparticles. Spectral dependence of the Faraday rotation for the studied nanocrystals and nanocomposites is correlated with a blueshift of the absorption edge due to the confinement effect in zero-dimensional structures. Faraday rotation spectra and their temperature behavior in Mn-doped nanocrystals demonstrates peculiarities, which are associated with s, p-d exchange interaction between Mn²⁺ ions and band carriers in diluted magnetic semiconductor nanostructures.

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

Benefits of rotational ground motions for planetary seismology

Science.gov (United States)

Donner, S.; Joshi, R.; Hadziioannou, C.; Nunn, C.; van Driel, M.; Schmelzbach, C.; Wassermann, J. M.; Igel, H.

2017-12-01

Exploring the internal structure of planetary objects is fundamental to understand the evolution of our solar system. In contrast to Earth, planetary seismology is hampered by the limited number of stations available, often just a single one. Classic seismology is based on the measurement of three components of translational ground motion. Its methods are mainly developed for a larger number of available stations. Therefore, the application of classical seismological methods to other planets is very limited. Here, we show that the additional measurement of three components of rotational ground motion could substantially improve the situation. From sparse or single station networks measuring translational and rotational ground motions it is possible to obtain additional information on structure and source. This includes direct information on local subsurface seismic velocities, separation of seismic phases, propagation direction of seismic energy, crustal scattering properties, as well as moment tensor source parameters for regional sources. The potential of this methodology will be highlighted through synthetic forward and inverse modeling experiments.

NONLINEAR DYNAMO IN A ROTATING ELECTRICALLY CONDUCTING FLUID

Directory of Open Access Journals (Sweden)

M. I. Kopp

2017-05-01

Full Text Available We found a new large-scale instability, which arises in the rotating conductive fluid with small-scale turbulence. Turbulence is generated by small-scale external force with a low Reynolds number. The theory is built simply by the method of multiscale asymptotic expansions. Nonlinear equations for vortex and magnetic perturbations obtained in the third order for small Reynolds number. It is shown that the combined effects of the Coriolis force and the small external forces in a rotating conducting fluid possible large-scale instability. The large-scale increments of the instability, correspond to generation as the vortex and magnetic disturbances. This type of instability is classified as hydrodynamic and MHD alpha-effect. We studied the stationary regimes of nonlinear equations of magneto-vortex dynamo. In the limit of weakly conducting fluid found stationary solutions in the form of helical kinks. In the limit of high conductivity fluid was obtained stationary solutions in the form of nonlinear periodic waves and kinks.

Managing carbon sinks by changing rotation length in European forests

International Nuclear Information System (INIS)

Kaipainen, Terhi; Liski, Jari; Pussinen, Ari; Karjalainen, Timo

2004-01-01

Elongation of rotation length is a forest management activity countries may choose to apply under Article 3.4 of the Kyoto Protocol to help them meet their commitments for reduction of greenhouse gas emissions. We used the CO2FIX model to analyze how the carbon stocks of trees, soil and wood products depend on rotation length in different European forests. Results predicted that the carbon stock of trees increased in each forest when rotation length was increased, but the carbon stock of soil decreased slightly in German and Finnish Scots pine forests; the carbon stock of wood products also decreased slightly in cases other than the Sitka spruce forest in UK. To estimate the efficiency of increasing rotation length as an Article 3.4 activity, we looked at changes in the carbon stock of trees resulting from a 20-year increase in current rotation lengths. To achieve the largest eligible carbon sink mentioned in Article 3.4 of the Kyoto Protocol, the rotation lengths need to be increased on areas varying from 0.3 to 5.1 Mha depending on the forest. This would in some forests cause 1-6% declines in harvesting possibilities. The possible decreases in the carbon stock of soil indicate that reporting the changes in the carbon stocks of forests under Article 3.4 may require measuring soil carbon

Radial magnetic resonance imaging (MRI) using a rotating radiofrequency (RF) coil at 9.4 T.

Science.gov (United States)

Li, Mingyan; Weber, Ewald; Jin, Jin; Hugger, Thimo; Tesiram, Yasvir; Ullmann, Peter; Stark, Simon; Fuentes, Miguel; Junge, Sven; Liu, Feng; Crozier, Stuart

2018-02-01

The rotating radiofrequency coil (RRFC) has been developed recently as an alternative approach to multi-channel phased-array coils. The single-element RRFC avoids inter-channel coupling and allows a larger coil element with better B 1 field penetration when compared with an array counterpart. However, dedicated image reconstruction algorithms require accurate estimation of temporally varying coil sensitivities to remove artefacts caused by coil rotation. Various methods have been developed to estimate unknown sensitivity profiles from a few experimentally measured sensitivity maps, but these methods become problematic when the RRFC is used as a transceiver coil. In this work, a novel and practical radial encoding method is introduced for the RRFC to facilitate image reconstruction without the measurement or estimation of rotation-dependent sensitivity profiles. Theoretical analyses suggest that the rotation-dependent sensitivities of the RRFC can be used to create a uniform profile with careful choice of sampling positions and imaging parameters. To test this new imaging method, dedicated electronics were designed and built to control the RRFC speed and hence positions in synchrony with imaging parameters. High-quality phantom and animal images acquired on a 9.4 T pre-clinical scanner demonstrate the feasibility and potential of this new RRFC method. Copyright © 2017 John Wiley & Sons, Ltd.

A plastic collapse method for evaluating rotation capacity of full-restrained steel moment connections

Directory of Open Access Journals (Sweden)

Lee Kyungkoo

2008-01-01

Full Text Available An analytical method to model failure of steel beam plastic hinges due to local buckling and low-cycle fatigue is proposed herein. This method is based on the plastic collapse mechanism approach and a yield-line plastic hinge (YLPH model whose geometry is based on buckled shapes of beam plastic hinges observed in experiments. Two limit states, strength degradation failure induced by local buckling and low-cycle fatigue fracture, are considered. The proposed YLPH model was developed for FEMA-350 WUF-W, RBS and Free Flange connections and validated in comparisons to experimental data. This model can be used to estimate the seismic rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames under both monotonic and cyclic loading conditions.

Fundamental limits to frequency estimation: a comprehensive microscopic perspective

Science.gov (United States)

Haase, J. F.; Smirne, A.; Kołodyński, J.; Demkowicz-Dobrzański, R.; Huelga, S. F.

2018-05-01

We consider a metrology scenario in which qubit-like probes are used to sense an external field that affects their energy splitting in a linear fashion. Following the frequency estimation approach in which one optimizes the state and sensing time of the probes to maximize the sensitivity, we provide a systematic study of the attainable precision under the impact of noise originating from independent bosonic baths. Specifically, we invoke an explicit microscopic derivation of the probe dynamics using the spin-boson model with weak coupling of arbitrary geometry. We clarify how the secular approximation leads to a phase-covariant (PC) dynamics, where the noise terms commute with the field Hamiltonian, while the inclusion of non-secular contributions breaks the PC. Moreover, unless one restricts to a particular (i.e., Ohmic) spectral density of the bath modes, the noise terms may contain relevant information about the frequency to be estimated. Thus, by considering general evolutions of a single probe, we study regimes in which these two effects have a non-negligible impact on the achievable precision. We then consider baths of Ohmic spectral density yet fully accounting for the lack of PC, in order to characterize the ultimate attainable scaling of precision when N probes are used in parallel. Crucially, we show that beyond the semigroup (Lindbladian) regime the Zeno limit imposing the 1/N 3/2 scaling of the mean squared error, recently derived assuming PC, generalises to any dynamics of the probes, unless the latter are coupled to the baths in the direction perfectly transversal to the frequency encoding—when a novel scaling of 1/N 7/4 arises. As our microscopic approach covers all classes of dissipative dynamics, from semigroup to non-Markovian ones (each of them potentially non-phase-covariant), it provides an exhaustive picture, in which all the different asymptotic scalings of precision naturally emerge.

Effect of rotational diffusion in an orientational potential well on the point spread function of electric dipole emitters.

Science.gov (United States)

Stallinga, Sjoerd

2015-02-01

A study is presented of the point spread function (PSF) of electric dipole emitters that go through a series of absorption-emission cycles while the dipole orientation is changing due to rotational diffusion within the constraint of an orientational potential well. An analytical expression for the PSF is derived valid for arbitrary orientational potential wells in the limit of image acquisition times much larger than the rotational relaxation time. This framework is used to study the effects of the direction of incidence, polarization, and degree of coherence of the illumination. In the limit of fast rotational diffusion on the scale of the fluorescence lifetime the illumination influences only the PSF height, not its shape. In the limit of slow rotational diffusion on the scale of the fluorescence lifetime there is a significant effect on the PSF shape as well, provided the illumination is (partially) coherent. For oblique incidence, illumination asymmetries can arise in the PSF that give rise to position offsets in localization based on Gaussian spot fitting. These asymmetries persist in the limit of free diffusion in a zero orientational potential well.

Error field assessment from driven rotation of stable external kinks at EXTRAP-T2R reversed field pinch

Science.gov (United States)

Volpe, F. A.; Frassinetti, L.; Brunsell, P. R.; Drake, J. R.; Olofsson, K. E. J.

2013-04-01

A new non-disruptive error field (EF) assessment technique not restricted to low density and thus low beta was demonstrated at the EXTRAP-T2R reversed field pinch. Stable and marginally stable external kink modes of toroidal mode number n = 10 and n = 8, respectively, were generated, and their rotation sustained, by means of rotating magnetic perturbations of the same n. Due to finite EFs, and in spite of the applied perturbations rotating uniformly and having constant amplitude, the kink modes were observed to rotate non-uniformly and be modulated in amplitude. This behaviour was used to precisely infer the amplitude and approximately estimate the toroidal phase of the EF. A subsequent scan permitted to optimize the toroidal phase. The technique was tested against deliberately applied as well as intrinsic EFs of n = 8 and 10. Corrections equal and opposite to the estimated error fields were applied. The efficacy of the error compensation was indicated by the increased discharge duration and more uniform mode rotation in response to a uniformly rotating perturbation. The results are in good agreement with theory, and the extension to lower n, to tearing modes and to tokamaks, including ITER, is discussed.

ASTEROID LIGHT CURVES FROM THE PALOMAR TRANSIENT FACTORY SURVEY: ROTATION PERIODS AND PHASE FUNCTIONS FROM SPARSE PHOTOMETRY

Energy Technology Data Exchange (ETDEWEB)

Waszczak, Adam [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Chang, Chan-Kao; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Laher, Russ; Surace, Jason [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Masci, Frank; Helou, George [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Levitan, David; Prince, Thomas A.; Kulkarni, Shrinivas, E-mail: waszczak@caltech.edu [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

2015-09-15

We fit 54,296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ∼53,000 fitted periods. By this method we find that 9033 of our light curves (of ∼8300 unique asteroids) have “reliable” periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these “reliable” periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ∼2 g cm{sup −3}, while C types have a lower limit of between 1 and 2 g cm{sup −3}. These results are in agreement with previous density estimates. For 5–20 km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types’ differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center’s nominal (G = 0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms

Integration of Visual and Vestibular Information Used to Discriminate Rotational Self-Motion

Directory of Open Access Journals (Sweden)

Florian Soyka

2011-10-01

Full Text Available Do humans integrate visual and vestibular information in a statistically optimal fashion when discriminating rotational self-motion stimuli? Recent studies are inconclusive as to whether such integration occurs when discriminating heading direction. In the present study eight participants were consecutively rotated twice (2s sinusoidal acceleration on a chair about an earth-vertical axis in vestibular-only, visual-only and visual-vestibular trials. The visual stimulus was a video of a moving stripe pattern, synchronized with the inertial motion. Peak acceleration of the reference stimulus was varied and participants reported which rotation was perceived as faster. Just-noticeable differences (JND were estimated by fitting psychometric functions. The visual-vestibular JND measurements are too high compared to the predictions based on the unimodal JND estimates and there is no JND reduction between visual-vestibular and visual-alone estimates. These findings may be explained by visual capture. Alternatively, the visual precision may not be equal between visual-vestibular and visual-alone conditions, since it has been shown that visual motion sensitivity is reduced during inertial self-motion. Therefore, measuring visual-alone JNDs with an underlying uncorrelated inertial motion might yield higher visual-alone JNDs compared to the stationary measurement. Theoretical calculations show that higher visual-alone JNDs would result in predictions consistent with the JND measurements for the visual-vestibular condition.

Gaussian limit of compact spin systems

International Nuclear Information System (INIS)

Bellissard, J.; Angelis, G.F. de

1981-01-01

It is shown that the Wilson and Wilson-Villain U(1) models reproduce, in the low coupling limit, the gaussian lattice approximation of the Euclidean electromagnetic field. By the same methods it is also possible to prove that the plane rotator and the Villain model share a common gaussian behaviour in the low temperature limit. (Auth.)

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1976-01-01

Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

Productivity of grasslands under continuous and rotational grazing

NARCIS (Netherlands)

Lantinga, E.A.

1985-01-01

In the Netherlands, rotational grazing, with grazing periods of 2 to 5 days, is the most common grazing system at present. In contrast with other countries of North-western Europe, the continuous grazing system is used here only to a limited extent. However, the results of numerous

Spinning and rotating strings for N=1 SYM theory and brane constructions

International Nuclear Information System (INIS)

Schvellinger, Martin

2004-01-01

We obtain spinning and rotating closed string solutions in AdS 5 x T 1,1 background, and show how these solutions can be mapped onto rotating closed strings embedded in configurations of intersecting branes in type IIA string theory. Then, we discuss spinning closed string solutions in the UV limit of the Klebanov-Tseytlin background, and also properties of classical solutions in the related intersecting brane constructions in the UV limit. We comment on extensions of this analysis to the deformed conifold background, and in the corresponding intersecting brane construction, as well as its relation to the deep IR limit of the Klebanov-Strassler solution. We briefly discuss on the relation between type IIA brane constructions and their related M-theory descriptions, and how solitonic solutions are related in both descriptions. (author)

Interaction between subdaily Earth rotation parameters and GPS orbits

Science.gov (United States)

Panafidina, Natalia; Seitz, Manuela; Hugentobler, Urs

2013-04-01

In processing GPS observations the geodetic parameters like station coordinates and ERPs (Earth rotation parameters) are estimated w.r.t. the celestial reference system realized by the satellite orbits. The interactions/correlations between estimated GPS orbis and other parameters may lead to numerical problems with the solution and introduce systematic errors in the computed values: the well known correlations comprise 1) the correlation between the orbital parameters determining the orientation of the orbital plane in inertial space and the nutation and 2) in the case of estimating ERPs with subdaily resolution the correlation between retrograde diurnal polar motion and nutation (and so the respective orbital elements). In this contribution we study the interaction between the GPS orbits and subdaily model for the ERPs. Existing subdaily ERP model recommended by the IERS comprises ~100 terms in polar motion and ~70 terms in Universal Time at diurnal and semidiurnal tidal periods. We use a long time series of daily normal equation systems (NEQ) obtaine from GPS observations from 1994 till 2007 where the ERPs with 1-hour resolution are transformed into tidal terms and the influence of the tidal terms with different frequencies on the estimated orbital parameters is considered. We found that although there is no algebraic correlation in the NEQ between the individual orbital parameters and the tidal terms, the changes in the amplitudes of tidal terms with periods close to 24 hours can be better accmodated by systematic changes in the orbital parameters than for tidal terms with other periods. Since the variation in Earth rotation with the period of siderial day (23.93h, tide K1) in terrestrial frame has in inertial space the same period as the period of revolution of GPS satellites, the K1 tidal term in polar motion is seen by the satellites as a permanent shift. The tidal terms with close periods (from ~24.13h to ~23.80h) are seen as a slow rotation of the

Patient reported activities after reverse total shoulder arthroplasty in rotator cuff arthropathy patients.

Science.gov (United States)

Alcobía-Díaz, B; Lópiz, Y; García-Fernández, C; Rizo de Álvaro, B; Marco, F

Reverse total shoulder arthroplasty in rotator cuff arthropathy patients, improves anteversion and abduction, but not rotational, outcomes. The main aim of this study is to determine its repercussions on daily life activities in our patients. Between 2009 and 2011 we implanted 210 shoulder arthroplasties, 126 of them were reverse total shoulder arthroplasty in a rotator cuff arthropathy context. About 88% were women, with a mean age at time of surgery of 81 years, 95% were retired. The mean follow up was 53 months. The Constant scale, Visual Analogue Scale, Charlson Comorbidity Index, range of motion were measured for each patient and whether they could manage 40 daily life activities by means of a new questionnaire, classifying them according toshoulder functional demand. Mean normalized by sex and age Constant value was 81.2%. Mean Visual Analogue Scale and Charlson Index were 3.56 and 1.69 respectively. Improvement in anteversion and abduction, not in rotational range of motion. Limitation was found in low and high functional demand activities in 20% and 51% respectively, especially those which involved internal rotation. Reverse total shoulder arthroplasty treatment for RCA in the elderly, achieves adequate pain management and good functional outcomes. Nevertheless, an important risk of DLA limitation must be accepted in those which involve internal rotation or shoulder high functional demand. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Spin-rotation and NMR shielding constants in HCl

Energy Technology Data Exchange (ETDEWEB)

Jaszuński, Michał, E-mail: michal.jaszunski@icho.edu.pl [Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warszawa, Kasprzaka 44 (Poland); Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø—The Arctic University of Norway, N-9037 Tromsø (Norway); Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz [Laboratory of NMR Spectroscopy, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

2013-12-21

The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of {sup 1}H{sup 35}Cl are C{sub Cl}  = −53.914 kHz and C{sub H}  = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values.

Spin-rotation and NMR shielding constants in HCl

International Nuclear Information System (INIS)

Jaszuński, Michał; Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth; Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz

2013-01-01

The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of 1 H 35 Cl are C Cl   = −53.914 kHz and C H   = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values

Intensity modulation of therapeutic photon beams using a rotating multileaf collimator

International Nuclear Information System (INIS)

Otto, Karl

2004-01-01

The thesis describes the development and implementation of a novel method of delivering intensity modulated radiation therapy (IMRT) that provides greater accuracy and spatial resolution than currently available methods. Through improvements in multileaf collimator (MLC) based fluence generation, a dose distribution may be generated that conforms more closely to the tumour target volume. Healthy tissue surrounding the target volume will therefore receive less dose, reducing the probability of side effects and allowing the physician to increase the prescribed tumor dose (dose escalation). As a preamble to the description of the IMRT delivery method a new model for evaluating the spatial resolution capabilities of dose delivery techniques is presented. Flexibility and complexity in patient treatment due to advances in radiotherapy techniques necessitates a simple method for evaluating spatial resolution capabilities of the dose delivery device. The model is based on linear systems theory and is analogous to methods used to describe resolution degradation in imaging systems. The spatial resolution capabilities of different delivery components can be quantified separately, providing a simple method for comparing different treatment machine characteristics. Also, the model provides the ability to evaluate spatial resolution changes independent of the tumor that is being treated, providing a means of comparing delivery techniques that is not biased by the characteristics of any particular treatment volume. MLC based IMRT techniques are well established but suffer several physical limitations. Dosimetric spatial resolution is limited by the MLC leaf width, interleaf leakage and tongue-and-groove effects degrade dosimetric accuracy and the range of leaf motion limits the maximum deliverable field size. Based on observations from the linear systems model it is hypothesized that, by rotating the entire MLC between each sub-field, improvements will be obtained in spatial

SU-F-E-12: Elective International Rotations in Medical Physics Residency Programs

Energy Technology Data Exchange (ETDEWEB)

Brown, D; Mundt, A; Einck, J; Pawlicki, T [University of California, San Diego, La Jolla, CA (United States)

2016-06-15

Purpose: The purpose of this educational program is to motivate talented, intelligent individuals to become stakeholders in the global effort to improve access to radiotherapy. Methods: The need to improve global access to radiotherapy has been clearly established and several organizations are making substantial progress in securing funding and developing plans to achieve this worthwhile goal. The incorporation of elective international rotations in residency programs may provide one possible mechanism to promote and support this future investment. We recently incorporated an elective 1-month international rotation into our CAMPEP accredited Medical Physics residency program, with our first rotation taking place in Vietnam. A unique aspect of this rotation was that it was scheduled collaboratively with our Radiation Oncology residency program such that Radiation Oncology and Medical Physics residents traveled to the same clinic at the same time. Results: We believe the international rotation substantially enhances the educational experience, providing additional benefits to residents by increasing cross-disciplinary learning and offering a shared learning experience. The combined international rotation may also increase benefit to the host institution by modeling positive multidisciplinary working relationships between Radiation Oncologists and Medical Physicists. Our first resident returned with several ideas designed to improve radiotherapy in resource-limited settings – one of which is currently being pursued in collaboration with a vendor. Conclusion: The elective international rotation provides a unique learning experience that has the potential to motivate residents to become stakeholders in the global effort to improve access to radiotherapy. What better way to prepare the next generation of Medical Physicists to meet the challenges of improving global access to radiotherapy than to provide them with training experiences that motivate them to be socially

SU-F-E-12: Elective International Rotations in Medical Physics Residency Programs

International Nuclear Information System (INIS)

Brown, D; Mundt, A; Einck, J; Pawlicki, T

2016-01-01

Purpose: The purpose of this educational program is to motivate talented, intelligent individuals to become stakeholders in the global effort to improve access to radiotherapy. Methods: The need to improve global access to radiotherapy has been clearly established and several organizations are making substantial progress in securing funding and developing plans to achieve this worthwhile goal. The incorporation of elective international rotations in residency programs may provide one possible mechanism to promote and support this future investment. We recently incorporated an elective 1-month international rotation into our CAMPEP accredited Medical Physics residency program, with our first rotation taking place in Vietnam. A unique aspect of this rotation was that it was scheduled collaboratively with our Radiation Oncology residency program such that Radiation Oncology and Medical Physics residents traveled to the same clinic at the same time. Results: We believe the international rotation substantially enhances the educational experience, providing additional benefits to residents by increasing cross-disciplinary learning and offering a shared learning experience. The combined international rotation may also increase benefit to the host institution by modeling positive multidisciplinary working relationships between Radiation Oncologists and Medical Physicists. Our first resident returned with several ideas designed to improve radiotherapy in resource-limited settings – one of which is currently being pursued in collaboration with a vendor. Conclusion: The elective international rotation provides a unique learning experience that has the potential to motivate residents to become stakeholders in the global effort to improve access to radiotherapy. What better way to prepare the next generation of Medical Physicists to meet the challenges of improving global access to radiotherapy than to provide them with training experiences that motivate them to be socially

High-Frequency Dynamic Nuclear Polarization in the Nuclear Rotating Frame

DEFF Research Database (Denmark)

Farrar, C. T.; Hall, D. A.; Gerfen, G. J.

2000-01-01

A proton dynamic nuclear polarization (DNP) NMR signal enhancement (ϵ) close to thermal equilibrium, ϵ = 0.89, has been obtained at high field (B0 = 5 T, νepr = 139.5 GHz) using 15 mM trityl radical in a 40:60 water/glycerol frozen solution at 11 K. The electron-nuclear polarization transfer...... is performed in the nuclear rotating frame with microwave irradiation during a nuclear spin-lock pulse. The growth of the signal enhancement is governed by the rotating frame nuclear spin–lattice relaxation time (T1ρ), which is four orders of magnitude shorter than the nuclear spin–lattice relaxation time (T1n......). Due to the rapid polarization transfer in the nuclear rotating frame the experiment can be recycled at a rate of 1/T1ρ and is not limited by the much slower lab frame nuclear spin–lattice relaxation rate (1/T1n). The increased repetition rate allowed in the nuclear rotating frame provides an effective...

Limitations to estimating bacterial cross-speciestransmission using genetic and genomic markers: inferencesfrom simulation modeling

Science.gov (United States)

Julio Andre, Benavides; Cross, Paul C.; Luikart, Gordon; Scott, Creel

2014-01-01

Cross-species transmission (CST) of bacterial pathogens has major implications for human health, livestock, and wildlife management because it determines whether control actions in one species may have subsequent effects on other potential host species. The study of bacterial transmission has benefitted from methods measuring two types of genetic variation: variable number of tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). However, it is unclear whether these data can distinguish between different epidemiological scenarios. We used a simulation model with two host species and known transmission rates (within and between species) to evaluate the utility of these markers for inferring CST. We found that CST estimates are biased for a wide range of parameters when based on VNTRs and a most parsimonious reconstructed phylogeny. However, estimations of CST rates lower than 5% can be achieved with relatively low bias using as low as 250 SNPs. CST estimates are sensitive to several parameters, including the number of mutations accumulated since introduction, stochasticity, the genetic difference of strains introduced, and the sampling effort. Our results suggest that, even with whole-genome sequences, unbiased estimates of CST will be difficult when sampling is limited, mutation rates are low, or for pathogens that were recently introduced.

Rotating night shift work, sleep, and colorectal adenoma in women.

Science.gov (United States)

Devore, Elizabeth E; Massa, Jennifer; Papantoniou, Kyriaki; Schernhammer, Eva S; Wu, Kana; Zhang, Xuehong; Willett, Walter C; Fuchs, Charles S; Chan, Andrew T; Ogino, Shuji; Giovannucci, Edward; Wei, Esther K

2017-07-01

This study aims to investigate the associations of rotating night shift work history and sleep duration with risk of colorectal adenoma. We evaluated 56,275 cancer-free participants of the Nurses' Health Study II, who had their first colonoscopy or sigmoidoscopy between 1991 and 2011; rotating night shift work and sleep duration were reported by mailed questionnaire. Multivariable-adjusted logistic regression was used to estimate relative risks (RR) of colorectal adenoma, with 95% confidence intervals (CI), across categories of rotating night shift work history (none, 1-4, 5-9, and ≥10 years) and sleep duration (≤5, 6, 7, 8, and ≥9 h/day). We found no association between duration of rotating night shift work and occurrence of colorectal adenoma (p-trend across shift work categories = 0.5). Women with the longest durations of rotating night shift work (≥10 years) had a similar risk of adenoma compared to women without a history of rotating night shift work (multivariable-adjusted RR = 0.96, 95% CI = 0.83-1.11). Similarly, there were no associations of shorter or longer sleep durations with adenoma risk (p-trend = 0.2 across sleep durations of ≤5 through 7 h/day and p-trend = 0.5 across sleep durations of 7 through ≥9 h/day). Results were similar when we examined associations according to adenoma location and subtype. Our results do not support an association between rotating night shift work or sleep duration and risk of colorectal adenoma in women.

Null result for violation of the equivalence principle with free-fall rotating gyroscopes

International Nuclear Information System (INIS)

Luo, J.; Zhou, Z.B.; Nie, Y.X.; Zhang, Y.Z.

2002-01-01

The differential acceleration between a rotating mechanical gyroscope and a nonrotating one is directly measured by using a double free-fall interferometer, and no apparent differential acceleration has been observed at the relative level of 2x10 -6 . It means that the equivalence principle is still valid for rotating extended bodies, i.e., the spin-gravity interaction between the extended bodies has not been observed at this level. Also, to the limit of our experimental sensitivity, there is no observed asymmetrical effect or antigravity of the rotating gyroscopes as reported by Hayasaka et al

Surface dimpling on rotating work piece using rotation cutting tool

Science.gov (United States)

Bhapkar, Rohit Arun; Larsen, Eric Richard

2015-03-31

A combined method of machining and applying a surface texture to a work piece and a tool assembly that is capable of machining and applying a surface texture to a work piece are disclosed. The disclosed method includes machining portions of an outer or inner surface of a work piece. The method also includes rotating the work piece in front of a rotating cutting tool and engaging the outer surface of the work piece with the rotating cutting tool to cut dimples in the outer surface of the work piece. The disclosed tool assembly includes a rotating cutting tool coupled to an end of a rotational machining device, such as a lathe. The same tool assembly can be used to both machine the work piece and apply a surface texture to the work piece without unloading the work piece from the tool assembly.

Charged rotating black holes on a 3-brane

International Nuclear Information System (INIS)

Aliev, A.N.; Guemruekcueoglu, A.E.

2005-01-01

We study exact stationary and axisymmetric solutions describing charged rotating black holes localized on a 3-brane in the Randall-Sundrum braneworld. The charges of the black holes are considered to be of two types, the first being an induced tidal charge that appears as an imprint of nonlocal gravitational effects from the bulk space and the second is a usual electric charge arising due to a Maxwell field trapped on the brane. We assume a special ansatz for the metric on the brane taking it to be of the Kerr-Schild form and show that the Kerr-Newman solution of ordinary general relativity in which the electric charge is superseded by a tidal charge satisfies a closed system of the effective gravitational field equations on the brane. It turns out that the negative tidal charge may provide a mechanism for spinning up the black hole so that its rotation parameter exceeds its mass. This is not allowed in the framework of general relativity. We also find a new solution that represents a rotating black hole on the brane carrying both charges. We show that for a rapid enough rotation the combined influence of the rotational dynamics and the local bulk effects of the 'squared' energy-momentum tensor on the brane distort the horizon structure of the black hole in such a way that it can be thought of as composed of nonuniformly rotating null circles with growing radii from the equatorial plane to the poles. We finally study the geodesic motion of test particles in the equatorial plane of a rotating black hole with tidal charge. We show that the effects of negative tidal charge tend to increase the horizon radius, as well as the radii of the limiting photon orbit, the innermost bound and the innermost stable circular orbits for both direct and retrograde motions of the particles

Experimental verification on limit load estimation method for pipes with an arbitrary shaped circumferential surface flaw

International Nuclear Information System (INIS)

Li, Yinsheng; Hasegawa, Kunio; Miura, Naoki; Hoshino, Katsuaki

2010-01-01

When a flaw is detected in stainless steel pipes during in-service inspection, the limit load criterion given in the codes such as JSME Rules on Fitness-for-Service for Nuclear Power Plants or ASME Boiler and Pressure Vessel Code Section XI can be applied to evaluate the integrity of the pipe. However, in these codes, the limit load criterion is only provided for pipes containing a flaw with uniform depth, although many flaws with complicated shape such as stress corrosion cracking have been actually detected in pipes. In order to evaluate the integrity of the flawed pipes for general case, a limit load estimation method has been proposed by authors considering a circumferential surface flaw with arbitrary shape. The plastic collapse bending moment and corresponding stress are obtained by dividing the surface flaw into several segmented sub-flaws. In this paper, the proposed method was verified by comparing with experimental results. Four-point bending experiments were carried out for full scale stainless steel pipes with a symmetrical or non-symmetrical circumferential flaw. Estimated failure bending moments by the proposed method were found to be in good agreement with the experimental results, and the proposed method was confirmed to be effective for evaluating bending failure of pipes with flaw. (author)

Generalisation, decision making, and embodiment effects in mental rotation: A neurorobotic architecture tested with a humanoid robot.

Science.gov (United States)

Seepanomwan, Kristsana; Caligiore, Daniele; Cangelosi, Angelo; Baldassarre, Gianluca

2015-12-01

Mental rotation, a classic experimental paradigm of cognitive psychology, tests the capacity of humans to mentally rotate a seen object to decide if it matches a target object. In recent years, mental rotation has been investigated with brain imaging techniques to identify the brain areas involved. Mental rotation has also been investigated through the development of neural-network models, used to identify the specific mechanisms that underlie its process, and with neurorobotics models to investigate its embodied nature. Current models, however, have limited capacities to relate to neuro-scientific evidence, to generalise mental rotation to new objects, to suitably represent decision making mechanisms, and to allow the study of the effects of overt gestures on mental rotation. The work presented in this study overcomes these limitations by proposing a novel neurorobotic model that has a macro-architecture constrained by knowledge held on brain, encompasses a rather general mental rotation mechanism, and incorporates a biologically plausible decision making mechanism. The model was tested using the humanoid robot iCub in tasks requiring the robot to mentally rotate 2D geometrical images appearing on a computer screen. The results show that the robot gained an enhanced capacity to generalise mental rotation to new objects and to express the possible effects of overt movements of the wrist on mental rotation. The model also represents a further step in the identification of the embodied neural mechanisms that may underlie mental rotation in humans and might also give hints to enhance robots' planning capabilities. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Absence of sex differences in mental rotation performance in autism spectrum disorder.

Science.gov (United States)

Rohde, Melanie S; Georgescu, Alexandra L; Vogeley, Kai; Fimmers, Rolf; Falter-Wagner, Christine M

2017-08-01

Mental rotation is one of the most investigated cognitive functions showing consistent sex differences. The 'Extreme Male Brain' hypothesis attributes the cognitive profile of individuals with autism spectrum disorder to an extreme version of the male cognitive profile. Previous investigations focused almost exclusively on males with autism spectrum disorder with only limited implications for affected females. This study is the first testing a sample of 12 female adults with high-functioning autism spectrum disorder compared to 14 males with autism spectrum disorder, 12 typically developing females and 14 typically developing males employing a computerised version of the mental rotation test. Reaction time and accuracy served as dependent variables. Their linear relationship with degree of rotation allows separation of rotational aspects of the task, indicated by slopes of the psychometric function, and non-rotational aspects, indicated by intercepts of the psychometric function. While the typical and expected sex difference for rotational task aspects was corroborated in typically developing individuals, no comparable sex difference was found in autism spectrum disorder individuals. Autism spectrum disorder and typically developing individuals did not differ in mental rotation performance. This finding does not support the extreme male brain hypothesis of autism.

On the Rotating and Oscillating strings in $(AdS_3\\times S^3)_{\\varkappa}$

CERN Document Server

Banerjee, Aritra

2014-01-01

We study rigidly rotating strings in the $\\varkappa$-deformed $AdS_3 \\times S^3$ background. We find out two classes of solutions corresponding to the giant magnon and single spike solutions of the string rotating is two $S^2_{\\varkappa}$ subspace of rotations reduced along two different isometries. We verify that the dispersion relations reduce to the well known relation in the $\\varkappa\\rightarrow 0$ limit. We further study some oscillating string solutions in the $S^3_{\\varkappa}$ subspace.

Prediction of secular acceleration of axial rotation of Mars

Science.gov (United States)

Barkin, Yu. V.

2009-04-01

axial rotation which as it would be possible to expect, essentially surpasses the similar characteristic of rotation of the Earth. The obtained result means, that angular velocity of Mars in present period increases on the law r = (0.708821808000+ 0.000000001038×t) × 10-4 1/s, here t - in years. It is possible assume that the estimation of acceleration can be obtained directly on the basis of the data of observations in the nearest years. Velocity of secular change of duration of day for Mars (LOD) thus can make significant value about -0.0903 ms/yr, that considerably surpasses similar value for non-tidal acceleration of the Earth (-0.006 ms/yr). The ratio of positive acceleration of the Earth rotation ṙ to its angular velocity ? makes ṙ•? = (6.9± 1.7) × 10-11 1/yr[7]. In case of Mars the estimation of acceleration was carried out under the formula [8]: ṙ/ ? = -Ċ• C -á¹ °• G ?-Ċ• C = 103.8 × 10-11 1/yr. We here have neglected by an influence of secular change of the axial angular momentum of fluid masses (atmospheric and underground) of Marsá¹ °. As shown in other my report on EGU GA 2009 in case of the Earth the total angular momentum of fluids really is small and within the limits of mistakes can be accepted equal to zero. In the case of Mars we the same as and in case of the Earth, expect of secular change of the angular momentum of Mars and change of global superrotation of its atmosphere which, at least, in part, will be compensated by the angular momentum of fluids. Thus, expected non-tidal acceleration of axial rotation of Mars can be at 10-15 times more those, but observably by astronomical methods, for the Earth. Certainly, the estimations obtained here are preliminary and the phenomena discussed here require more detailed studying with using of new data of precision observations. First of all it is important to obtain the specified values of secular variations ˙ J2 and ˙ J3. In case of the Earth the tidal deceleration

The rotating universe

International Nuclear Information System (INIS)

Ruben, G.; Treder, H.J.

1987-01-01

For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

Rotation sensor switch

International Nuclear Information System (INIS)

Sevec, J.B.

1978-01-01

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

Gastight Hydrodynamic Electrochemistry: Design for a Hermetically Sealed Rotating Disk Electrode Cell.

Science.gov (United States)

Jung, Suho; Kortlever, Ruud; Jones, Ryan J R; Lichterman, Michael F; Agapie, Theodor; McCrory, Charles C L; Peters, Jonas C

2017-01-03

Rotating disk electrodes (RDEs) are widely used in electrochemical characterization to analyze the mechanisms of various electrocatalytic reactions. RDE experiments often make use of or require collection and quantification of gaseous products. The combination of rotating parts and gaseous analytes makes the design of RDE cells that allow for headspace analysis challenging due to gas leaks at the interface of the cell body and the rotator. In this manuscript we describe a new, hermetically sealed electrochemical cell that allows for electrode rotation while simultaneously providing a gastight environment. Electrode rotation in this new cell design is controlled by magnetically coupling the working electrode to a rotating magnetic driver. Calibration of the RDE using a tachometer shows that the rotation speed of the electrode is the same as that of the magnetic driver. To validate the performance of this cell for hydrodynamic measurements, limiting currents from the reduction of a potassium ferrocyanide (K 4 [Fe(CN) 6 ]·3H 2 O) were measured and shown to compare favorably with calculated values from the Levich equation and with data obtained using more typical, nongastight RDE cells. Faradaic efficiencies of ∼95% were measured in the gas phase for oxygen evolution in alkaline media at an Inconel 625 alloy electrocatalyst during rotation at 1600 rpm. These data verify that a gastight environment is maintained even during rotation.

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.

Multi-method automated diagnostics of rotating machines

Science.gov (United States)

Kostyukov, A. V.; Boychenko, S. N.; Shchelkanov, A. V.; Burda, E. A.

2017-08-01

The automated machinery diagnostics and monitoring systems utilized within the petrochemical plants are an integral part of the measures taken to ensure safety and, as a consequence, the efficiency of these industrial facilities. Such systems are often limited in their functionality due to the specifics of the diagnostic techniques adopted. As the diagnostic techniques applied in each system are limited, and machinery defects can have different physical nature, it becomes necessary to combine several diagnostics and monitoring systems to control various machinery components. Such an approach is inconvenient, since it requires additional measures to bring the diagnostic results in a single view of the technical condition of production assets. In this case, we mean by a production facility a bonded complex of a process unit, a drive, a power source and lines. A failure of any of these components will cause an outage of the production asset, which is unacceptable. The purpose of the study is to test a combined use of vibration diagnostics and partial discharge techniques within the diagnostic systems of enterprises for automated control of the technical condition of rotating machinery during maintenance and at production facilities. The described solutions allow you to control the condition of mechanical and electrical components of rotating machines. It is shown that the functionality of the diagnostics systems can be expanded with minimal changes in technological chains of repair and operation of rotating machinery. Automation of such systems reduces the influence of the human factor on the quality of repair and diagnostics of the machinery.

Rotating field current drive in spherical plasmas

International Nuclear Information System (INIS)

Brotherton-Ratcliffe, D.; Storer, R.G.

1988-01-01

The technique of driving a steady Hall current in plasmas using a rotating magnetic field is studied both numerically and analytically in the approximation of negligible ion flow. A spherical plasma bounded by an insulating wall and immersed in a uniform magnetic field which has both a rotating component (for current drive) and a constant ''vertical'' component (for MHD equilibrium) is considered. The problem is formulated in terms of an expansion of field quantities in vector spherical harmonics. The numerical code SPHERE solves the resulting pseudo-harmonic equations by a multiple shooting technique. The results presented, in addition to being relevant to non-inductive current drive generally, have a direct relevance to the rotamak experiments. For the case of no applied vertical field the steady state toroidal current driven by the rotating field per unit volume of plasma is several times less than in the long cylinder limit for a plasma of the same density, resistivity and radius. The application of a vertical field, which for certain parameter regimes gives rise to a compact torus configuration, improves the current drive dramatically and in many cases gives ''better'' current drive than the long cylinder limit. This result is also predicted by a second order perturbation analysis of the pseudo-harmonic equations. A steady state toroidal field is observed which appears consistent with experimental observations in rotamaks regarding magnitude and spatial dependence. This is an advance over previous analytical theory which predicted an oppositely directed toroidal field of undefined magnitude. (author)

Rotational temperature determinations in molecular gas lasers

International Nuclear Information System (INIS)

Weaver, L.A.; Taylor, L.H.; Denes, L.J.

1975-01-01

The small-signal gain expressions for vibrational-rotational transitions are examined in detail to determine possible methods of extracting the rotational temperature from experimental gain measurements in molecular gas lasers. Approximate values of T/subr/ can be deduced from the rotational quantum numbers for which the P- and R-branch gains are maximum. Quite accurate values of T/subr/ and the population inversion density (n/subv//sub prime/-n/subv//sub double-prime/) can be determined by fitting data to suitably linearized gain relationships, or by performing least-squares fits of the P- and R-branch experimental data to the full gain expressions. Experimental gain measurements for 15 P-branch and 12 R-branch transitions in the 10.4-μm CO 2 band have been performed for pulsed uv-preionized laser discharges in CO 2 : N 2 : He=1 : 2 : 3 mixtures at 600 Torr. These data are subjected to the several gain analyses described herein, yielding a rotational temperature of 401plus-or-minus10 degreeK and an inversion density of (3.77plus-or-minus0.07) times10 17 cm -3 for conditions of maximum gain. These techniques provide accurate values of the gas temperature in molecular gas lasers with excellent temporal and spatial resolution, and should be useful in extending the conversion efficiency and arcing limits of high-energy electrically exc []ted lasers

Linear analysis of rotationally invariant, radially variant tomographic imaging systems

International Nuclear Information System (INIS)

Huesmann, R.H.

1990-01-01

This paper describes a method to analyze the linear imaging characteristics of rotationally invariant, radially variant tomographic imaging systems using singular value decomposition (SVD). When the projection measurements from such a system are assumed to be samples from independent and identically distributed multi-normal random variables, the best estimate of the emission intensity is given by the unweighted least squares estimator. The noise amplification of this estimator is inversely proportional to the singular values of the normal matrix used to model projection and backprojection. After choosing an acceptable noise amplification, the new method can determine the number of parameters and hence the number of pixels that should be estimated from data acquired from an existing system with a fixed number of angles and projection bins. Conversely, for the design of a new system, the number of angles and projection bins necessary for a given number of pixels and noise amplification can be determined. In general, computing the SVD of the projection normal matrix has cubic computational complexity. However, the projection normal matrix for this class of rotationally invariant, radially variant systems has a block circulant form. A fast parallel algorithm to compute the SVD of this block circulant matrix makes the singular value analysis practical by asymptotically reducing the computation complexity of the method by a multiplicative factor equal to the number of angles squared

Surgical Pathology Resident Rotation Restructuring at a Tertiary Care Academic Center.

Science.gov (United States)

Mehr, Chelsea R; Obstfeld, Amrom E; Barrett, Amanda C; Montone, Kathleen T; Schwartz, Lauren E

2017-01-01

Changes in the field of pathology and resident education necessitate ongoing evaluation of residency training. Evolutionary change is particularly important for surgical pathology rotations, which form the core of anatomic pathology training programs. In the past, we organized this rotation based on subjective insight. When faced with the recent need to restructure the rotation, we strove for a more evidence-based process. Our approach involved 2 primary sources of data. We quantified the number of cases and blocks submitted per case type to estimate workload and surveyed residents about the time required to gross specimens in all organ systems. A multidisciplinary committee including faculty, residents, and staff evaluated the results and used the data to model how various changes to the rotation would affect resident workload, turnaround time, and other variables. Finally, we identified rotation structures that equally distributed work and created a point-based system that capped grossing time for residents of different experience. Following implementation, we retrospectively compared turnaround time and duty hour violations before and after these changes and surveyed residents about their experiences with both systems. We evaluated the accuracy of the point-based system by examining grossing times and comparing them to the assigned point values. We found overall improvement in the rotation following the implementation. As there is essentially no literature on the subject of surgical pathology rotation organization, we hope that our experience will provide a road map to improve pathology resident education at other institutions.

Surgical Pathology Resident Rotation Restructuring at a Tertiary Care Academic Center

Directory of Open Access Journals (Sweden)

Chelsea R. Mehr MD

2017-11-01

Full Text Available Changes in the field of pathology and resident education necessitate ongoing evaluation of residency training. Evolutionary change is particularly important for surgical pathology rotations, which form the core of anatomic pathology training programs. In the past, we organized this rotation based on subjective insight. When faced with the recent need to restructure the rotation, we strove for a more evidence-based process. Our approach involved 2 primary sources of data. We quantified the number of cases and blocks submitted per case type to estimate workload and surveyed residents about the time required to gross specimens in all organ systems. A multidisciplinary committee including faculty, residents, and staff evaluated the results and used the data to model how various changes to the rotation would affect resident workload, turnaround time, and other variables. Finally, we identified rotation structures that equally distributed work and created a point-based system that capped grossing time for residents of different experience. Following implementation, we retrospectively compared turnaround time and duty hour violations before and after these changes and surveyed residents about their experiences with both systems. We evaluated the accuracy of the point-based system by examining grossing times and comparing them to the assigned point values. We found overall improvement in the rotation following the implementation. As there is essentially no literature on the subject of surgical pathology rotation organization, we hope that our experience will provide a road map to improve pathology resident education at other institutions.

Trunk-rotation flexibility in collegiate softball players with or without a history of shoulder or elbow injury.

Science.gov (United States)

Aragon, Veronica J; Oyama, Sakiko; Oliaro, Scott M; Padua, Darin A; Myers, Joseph B

2012-01-01

Throwing is a whole-body motion that requires the transfer of momentum from the lower extremity to the upper extremity via the trunk. No research to date examines the association between a history of shoulder or elbow injury and trunk flexibility in overhead athletes. To determine if injury history and trunk-rotation flexibility are associated and to compare trunk-rotation flexibility measured using 3 clinical tests: half-kneeling rotation test with the bar in the back, half-kneeling rotation test with the bar in the front, and seated rotation test in softball position players with or without a history of shoulder or elbow injury. Cross-sectional design. University softball facilities. Sixty-five female National Collegiate Athletic Association Division I softball position players. Trunk-rotation flexibility was measured with 3 clinical tests. Recent injury history was obtained using a questionnaire and verified by the certified athletic trainer. Binomial regression models were used to determine if injury history was associated with flexibility categories (high, normal, or limited tertiles) for each of the 6 (3 tests × 2 directions) trunk-rotation flexibility measures. Trunk-rotation flexibility measures from 3 clinical tests were compared between participants with and without a history of shoulder or elbow injury using analysis-of-variance models. When measured using the half-kneeling rotation test with the bar in the back and the seated rotation test, injury history and forward trunk-rotation flexibility were associated. However, no mean group differences were seen in trunk-rotation flexibility between participants with and without a history of shoulder or elbow injury. Limited forward trunk-rotation flexibility may be a risk factor for shoulder or elbow injuries. However, further study is needed to confirm the study finding.

Transformation of heat into mechanical energy by means of rotating systems

Directory of Open Access Journals (Sweden)

Mešina Marian

2018-01-01

Full Text Available All heat engines need two different temperatures for their work, T1limited by the Carnot formula from above. This article presents a new conception for heat engines. Unlike conventional heat engines, the working medium has an additional degree of freedom, the rotation around a given axis. The heat introduced and removed can not only lead to a change in the parameters of temperature, pressure, and volume, which are considered in conventional thermodynamics, but also to a change in the state of rotation. The rotational speed must also be taken into account in all phases of the cycle for all efficiency calculations. In many cases, this leads to a surprisingly different result from the results of conventional thermodynamics, that the efficiency of the cycle can exceed the Carnot limit. The efficiency values depend not only on temperatures and rotational speeds, but also on the material data. The proposed new type of heat engine makes it possible to better utilise very small temperature differences and under certain conditions, in combination with an ideal heat pump, to extract ambient heat and convert it into mechanical energy. The calculated results were presented for simple geometry and can easily be verified experimentally. In combination with an ideal heat pump, the proposed heat engine facilitates the surroundings to withdraw heat and convert it into mechanical work.

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

PRE-SUPERNOVA EVOLUTION OF ROTATING SOLAR METALLICITY STARS IN THE MASS RANGE 13-120 M {sub Sun} AND THEIR EXPLOSIVE YIELDS

Energy Technology Data Exchange (ETDEWEB)

Chieffi, Alessandro [Istituto Nazionale di Astrofisica-Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Limongi, Marco, E-mail: alessandro.chieffi@inaf.it, E-mail: marco.limongi@oa-roma.inaf.it [Centre for Stellar and Planetary Astrophysics, School of Mathematical Sciences, P.O. Box 28M, Monash University, Victoria 3800 (Australia)

2013-02-10

We present the first set of a new generation of models of massive stars with a solar composition extending between 13 and 120 M {sub Sun }, computed with and without the effects of rotation. We included two instabilities induced by rotation: the meridional circulation and the shear instability. We implemented two alternative schemes to treat the transport of the angular momentum: the advection-diffusion formalism and the simpler purely diffusive one. The full evolution from the pre-main sequence up to the pre-supernova stage is followed in detail with a very extended nuclear network. The explosive yields are provided for a variety of possible mass cuts and are available at the Web site http://www.iasf-roma.inaf.it/orfeo/public{sub h}tml. We find that both the He and the CO core masses are larger than those of their non-rotating counterparts. Also the C abundance left by the He burning is lower than in the non-rotating case, especially for stars with an initial mass of 13-25 M {sub Sun }, and this affects the final mass-radius relation, basically the final binding energy, at the pre-supernova stage. The elemental yields produced by a generation of stars rotating initially at 300 km s{sup -1} do not change substantially with respect to those produced by a generation of non-rotating massive stars, the main differences being a slight overproduction of the weak s-component and a larger production of F. Since rotation also affects the mass-loss rate, either directly or indirectly, we find substantial differences in the lifetimes as O-type and Wolf-Rayet subtypes between the rotating and non-rotating models. The maximum mass exploding as Type IIP supernova ranges between 15 and 20 M {sub Sun} in both sets of models (this value depends basically on the larger mass-loss rates in the red supergiant phase due to the inclusion of the dust-driven wind). This limiting value is in remarkably good agreement with current estimates.

Unsteady flow of fractional Oldroyd-B fluids through rotating annulus

Science.gov (United States)

Tahir, Madeeha; Naeem, Muhammad Nawaz; Javaid, Maria; Younas, Muhammad; Imran, Muhammad; Sadiq, Naeem; Safdar, Rabia

2018-04-01

In this paper exact solutions corresponding to the rotational flow of a fractional Oldroyd-B fluid, in an annulus, are determined by applying integral transforms. The fluid starts moving after t = 0+ when pipes start rotating about their axis. The final solutions are presented in the form of usual Bessel and hypergeometric functions, true for initial and boundary conditions. The limiting cases for the solutions for ordinary Oldroyd-B, fractional Maxwell and Maxwell and Newtonian fluids are obtained. Moreover, the solution is obtained for the fluid when one pipe is rotating and the other one is at rest. At the end of this paper some characteristics of fluid motion, the effect of the physical parameters on the flow and a correlation between different fluid models are discussed. Finally, graphical representations confirm the above affirmation.

Fluorescent vibration-rotation excitation of cometary C2

International Nuclear Information System (INIS)

Gredel, R.; Van Dishoeck, E.F.; Black, J.H.

1989-01-01

The statistical equilibrium equations that determine the population densities of the energy levels in cometary C2 molecules due to fluorescent excitation are examined in detail. The adopted model and molecular parameters are discussed, and a theoretical estimate is made of the two intercombination transition moments. From the theoretical population densities in the various rotational levels, flux ratios and synthetic emission profiles are calculated as functions of the a 3Pi(u) - X 1Sigma(g)+ and the c 3Sigma(u)+ - X 3Sigma(g)+ intercombination transition moments. The influence of each of these two transitions separately on the vibrational and rotational excitation temperatures is investigated. The observed emission spectra of the (0,0) Swan band in Comet Halley are presented and compared to the synthetic profiles. 70 references

Fluorescent vibration-rotation excitation of cometary C2

Science.gov (United States)

Gredel, Roland; Van Dishoeck, Ewine F.; Black, John H.

1989-01-01

The statistical equilibrium equations that determine the population densities of the energy levels in cometary C2 molecules due to fluorescent excitation are examined in detail. The adopted model and molecular parameters are discussed, and a theoretical estimate is made of the two intercombination transition moments. From the theoretical population densities in the various rotational levels, flux ratios and synthetic emission profiles are calculated as functions of the a 3Pi(u) - X 1Sigma(g)+ and the c 3Sigma(u)+ - X 3Sigma(g)+ intercombination transition moments. The influence of each of these two transitions separately on the vibrational and rotational excitation temperatures is investigated. The observed emission spectra of the (0,0) Swan band in Comet Halley are presented and compared to the synthetic profiles.

Rotational state dependence of ion-polar molecule reactions at very low temperature

International Nuclear Information System (INIS)

Dubernet, M.L.; McCarroll, R.

1989-01-01

The adiabatic rotational state method is used to investigate the rotational state dependence of the rate coefficients for ion-polar molecule reactions in the very low temperature regime characteristic of interstellar molecular clouds. Results obtained for the systems H 3 + +HCl and H 3 + +HCN indicate that all the methods based on the adiabatic separation of the rotational and radial motion of the collision complex - adiabatic capture centrifugal sudden approximation (ACCSA), statistical adiabatic channel model, classical adiabatic invariance method - agree very satisfactorily in the low temperature limit. Discrepancies observed between some of the published data would appear to arise from numerical inaccuracies rather than from any defect of the theory. (orig.)

Limited sampling strategy models for estimating the AUC of gliclazide in Chinese healthy volunteers.

Science.gov (United States)

Huang, Ji-Han; Wang, Kun; Huang, Xiao-Hui; He, Ying-Chun; Li, Lu-Jin; Sheng, Yu-Cheng; Yang, Juan; Zheng, Qing-Shan

2013-06-01

The aim of this work is to reduce the cost of required sampling for the estimation of the area under the gliclazide plasma concentration versus time curve within 60 h (AUC0-60t ). The limited sampling strategy (LSS) models were established and validated by the multiple regression model within 4 or fewer gliclazide concentration values. Absolute prediction error (APE), root of mean square error (RMSE) and visual prediction check were used as criterion. The results of Jack-Knife validation showed that 10 (25.0 %) of the 40 LSS based on the regression analysis were not within an APE of 15 % using one concentration-time point. 90.2, 91.5 and 92.4 % of the 40 LSS models were capable of prediction using 2, 3 and 4 points, respectively. Limited sampling strategies were developed and validated for estimating AUC0-60t of gliclazide. This study indicates that the implementation of an 80 mg dosage regimen enabled accurate predictions of AUC0-60t by the LSS model. This study shows that 12, 6, 4, 2 h after administration are the key sampling times. The combination of (12, 2 h), (12, 8, 2 h) or (12, 8, 4, 2 h) can be chosen as sampling hours for predicting AUC0-60t in practical application according to requirement.

Elliptical Galaxies: Rotationally Distorted, After All

Directory of Open Access Journals (Sweden)

Caimmi, R.

2009-12-01

.15$, and low rotationparameters $(0lechi_v^2<0.15$, while fastrotators show large ellipticities $(0.2lehat{e}<0.65$, large anisotropy parameters$(0.15ledelta<0.35$, and large rotationparameters $(0.15lechi_v^2<0.5$. Analternative kinematic classification withrespect to earlier attempts (Emsellem etal. 2007 requires larger samples for providingadditional support to the above mentionedresults. A possible interpretation of slowrotators as nonrotating at all and elongated due to negative anisotropy parameters,instead of flattened due to positiveanisotropy parameters, is exploited.Finally, the elliptical side of the Hubblemorphological sequence is interpreted as asequence of equilibrium (adjoint configurations where the ellipticity is an increasing functionof the rotation parameter, slow rotators correspond to early classes (E0-E2 in the oblate limit and E2-E0 in the prolate limitand fast rotators to late classes (E3-E6.In this view, boundaries are rotationally distorted regardless of angular momentumand stress tensor, where rotation has tobe intended as due to additional kinetic energy of tangential equatorial velocity components,with respect to spherical configurations with isotropic stress tensor.

Multi-person localization and orientation estimation in volumetric scene reconstructions

NARCIS (Netherlands)

Liem, M.C.

2014-01-01

Accurate localization of persons and estimation of their pose are important topics in current-day computer vision research. As part of the pose estimation, estimating the body orientation of a person (i.e. rotation around torso major axis) conveys important information about the person's current

Optofluidic laser scanner based on a rotating liquid prism.

Science.gov (United States)

Kopp, Daniel; Lehmann, Lukas; Zappe, Hans

2016-03-20

We demonstrate an electrowetting-actuated optofluidic system based on a rotatable liquid prism implemented as a two-dimensional laser scanner. The system is fabricated through a novel technology using a patterned flexible polymeric foil on which a high density of electrodes is structured and which is subsequently inserted into a cylindrical housing. The resulting radial electrode array is used for electrowetting actuation of two fluids filled into the cylinder, which allows a controllable tilt and orientation of the planar liquid interface and thus represents a tunable rotating prism. Finite element simulations and subsequent experimental verification show that this highly planar and precisely positionable liquid/liquid interface may be actuated to a deflection angle of ±6.4°, with a standard deviation of ±0.18°, and rotated 360° about the vertical axis. Power consumption is limited to several microwatts, and switching times of several hundred milliseconds were determined.

The role of sea-ice albedo in the climate of slowly rotating aquaplanets

Science.gov (United States)

Salameh, Josiane; Popp, Max; Marotzke, Jochem

2018-04-01

We investigate the influence of the rotation period (P_{rot}) on the mean climate of an aquaplanet, with a focus on the role of sea-ice albedo. We perform aquaplanet simulations with the atmospheric general circulation model ECHAM6 for various rotation periods from one Earth-day to 365 Earth-days in which case the planet is synchronously rotating. The global-mean surface temperature decreases with increasing P_{rot} and sea ice expands equatorwards. The cooling of the mean climate with increasing P_{rot} is caused partly by the high surface albedo of sea ice on the dayside and partly by the high albedo of the deep convective clouds over the substellar region. The cooling caused by these deep convective clouds is weak for non-synchronous rotations compared to synchronous rotation. Sensitivity simulations with the sea-ice model switched off show that the global-mean surface temperature is up to 27 K higher than in our main simulations with sea ice and thus highlight the large influence of sea ice on the climate. We present the first estimates of the influence of the rotation period on the transition of an Earth-like climate to global glaciation. Our results suggest that global glaciation of planets with synchronous rotation occurs at substantially lower incoming solar irradiation than for planets with slow but non-synchronous rotation.

Estimating productivity of tropical forest plantations by climatic factors

Energy Technology Data Exchange (ETDEWEB)

Pandey, D.

1996-12-31

This study presents an alternative method of estimating wood production at regional/global levels from tropical plantations based on climatic variables. A generic model for estimating potential yield in tropical plantations was formulated. The model was developed for teak (Tectona grandis L. F.) as a case study. Available data of teak sample plots from India, Myanmar, Indonesia, Nigeria and Ivory Coast, consisting of 153 plots distributed over 38 meteorological stations were used. A new base age invariant site index function was developed and the site index of each plot was estimated. The mean annual volume increment (MAI) of each plot from existing yield tables was then interpolated. Treating MAI at 50 years (rotation age) as potential yield of teak, a model was constructed which could explain about 59% variance of the potential yield. Models constructed for estimating the maximum MAI and the site index of teak explained the variability up to 61% and 57% respectively. The models underestimated the productivity of teak in Indonesia, Nigeria and Ivory Coast. The rainfall and the relative humidity have been identified as the most important climatic variables influencing the growth of teak. The length of the growing season and the temperature of the warmest month of the growing season were found significant in the models. The temperature and the day length (sunshine) have not been found to be the limiting factors for the growth of teak. However, the maximum temperature beyond a certain upper limit has a negative effect on growth. The study indicates that this upper limit is around 33 deg C for teak. The models could be used to forecast the potential yield of the existing as well as planned teak plantations in the tropical region. 109 refs, 15 figs, 11 tabs

Numerical simulation of fluid flow in a rotational bioreactor

Science.gov (United States)

Ganimedov, V. L.; Papaeva, E. O.; Maslov, N. A.; Larionov, P. M.

2017-10-01

Application of scaffold technology for the problem of bone tissue regeneration has great prospects in modern medicine. The influence of fluid shear stress on stem cells cultivation and its differentiation into osteoblasts is the subject of intensive research. Mathematical modeling of fluid flow in bioreactor allowed us to determine the structure of flow and estimate the level of mechanical stress on cells. The series of computations for different rotation frequencies (0.083, 0.124, 0.167, 0.2 and 0.233 Hz) was performed for the laminar flow regime approximation. It was shown that the Taylor vortices in the gap between the cylinders qualitatively change the distribution of static pressure and shear stress in the region of vortices connection. It was shown that an increase in the rotation frequency leads to an increase of the unevenness in distribution of the above mentioned functions. The obtained shear stress and static pressure dependence on the rotational frequency make it possible to choose the operating mode of the reactor depending on the provided requirements. It was shown that in the range of rotation frequencies chosen in this work (0.083 < f < 0.233 Hz), the shear stress does not exceed the known literature data (0.002 - 0.1 Pa).

Reduced critical rotation for resistive-wall mode stabilization in a near-axisymmetric configuration.

Science.gov (United States)

Reimerdes, H; Garofalo, A M; Jackson, G L; Okabayashi, M; Strait, E J; Chu, M S; In, Y; La Haye, R J; Lanctot, M J; Liu, Y Q; Navratil, G A; Solomon, W M; Takahashi, H; Groebner, R J

2007-02-02

Recent DIII-D experiments with reduced neutral beam torque and minimum nonaxisymmetric perturbations of the magnetic field show a significant reduction of the toroidal plasma rotation required for the stabilization of the resistive-wall mode (RWM) below the threshold values observed in experiments that apply nonaxisymmetric magnetic fields to slow the plasma rotation. A toroidal rotation frequency of less than 10 krad/s at the q=2 surface (measured with charge exchange recombination spectroscopy using C VI) corresponding to 0.3% of the inverse of the toroidal Alfvén time is sufficient to sustain the plasma pressure above the ideal MHD no-wall stability limit. The low-rotation threshold is found to be consistent with predictions by a kinetic model of RWM damping.

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.

Renewable Energy Power Generation Estimation Using Consensus Algorithm

Science.gov (United States)

Ahmad, Jehanzeb; Najm-ul-Islam, M.; Ahmed, Salman

2017-08-01

At the small consumer level, Photo Voltaic (PV) panel based grid tied systems are the most common form of Distributed Energy Resources (DER). Unlike wind which is suitable for only selected locations, PV panels can generate electricity almost anywhere. Pakistan is currently one of the most energy deficient countries in the world. In order to mitigate this shortage the Government has recently announced a policy of net-metering for residential consumers. After wide spread adoption of DERs, one of the issues that will be faced by load management centers would be accurate estimate of the amount of electricity being injected in the grid at any given time through these DERs. This becomes a critical issue once the penetration of DER increases beyond a certain limit. Grid stability and management of harmonics becomes an important consideration where electricity is being injected at the distribution level and through solid state controllers instead of rotating machinery. This paper presents a solution using graph theoretic methods for the estimation of total electricity being injected in the grid in a wide spread geographical area. An agent based consensus approach for distributed computation is being used to provide an estimate under varying generation conditions.

Rotating black string and the effective Teukolsky equation in the braneworld

International Nuclear Information System (INIS)

Kanno, Sugumi; Soda, Jiro

2004-01-01

In the Randall-Sundrum two-brane (RS1) model, a large Kerr black hole on the brane can be naturally identified with a section of a rotating black string. To estimate Kaluza-Klein (KK) corrections on gravitational waves emitted by perturbed rotating black strings, we give the effective Teukolsky equation on the brane, which is a separable equation and hence numerically manageable. In this process, we derive the master equation for the electric part of the Weyl tensor, E μν , which is also useful in discussing the transition from black strings to localized black holes triggered by Gregory-Laflamme instability

NH3 quantum rotators in Hofmann clathrates: intensity and width of rotational transition lines

International Nuclear Information System (INIS)

Vorderwisch, Peter; Sobolev, Oleg; Desmedt, Arnaud

2004-01-01

Inelastic structure factors for rotational transitions of uniaxial NH 3 quantum rotators, measured in a Hofmann clathrate with biphenyl as guest molecule, agree with those calculated for free rotators. A finite intrinsic line width, found for rotational transitions involving the rotational level j=3 at low temperature, supports a recently suggested model based on resonant rotor-rotor coupling

Rotation Frequencies of Small Jovian Trojan Asteroids: An Excess of Slow Rotators

Science.gov (United States)

French, Linda M.; Stephens, Robert D.; James, David J.; Coley, Daniel; Connour, Kyle

2015-11-01

Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half the 131 objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015).A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004).Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

Estimation of Detection Thresholds for Audiovisual Rotation Gains

DEFF Research Database (Denmark)

Nilsson, Niels Chr.; Suma, Evan; Nordahl, Rolf

2016-01-01

Redirection techniques allow users to explore large virtual environments on foot while remaining within a limited physical space. However, research has primarily focused on redirection through manipulation of visual stimuli. We describe a within-subjects study (n=31) exploring if participants’ ab...

M-estimator for the 3D symmetric Helmert coordinate transformation

Science.gov (United States)

Chang, Guobin; Xu, Tianhe; Wang, Qianxin

2018-01-01

The M-estimator for the 3D symmetric Helmert coordinate transformation problem is developed. Small-angle rotation assumption is abandoned. The direction cosine matrix or the quaternion is used to represent the rotation. The 3 × 1 multiplicative error vector is defined to represent the rotation estimation error. An analytical solution can be employed to provide the initial approximate for iteration, if the outliers are not large. The iteration is carried out using the iterative reweighted least-squares scheme. In each iteration after the first one, the measurement equation is linearized using the available parameter estimates, the reweighting matrix is constructed using the residuals obtained in the previous iteration, and then the parameter estimates with their variance-covariance matrix are calculated. The influence functions of a single pseudo-measurement on the least-squares estimator and on the M-estimator are derived to theoretically show the robustness. In the solution process, the parameter is rescaled in order to improve the numerical stability. Monte Carlo experiments are conducted to check the developed method. Different cases to investigate whether the assumed stochastic model is correct are considered. The results with the simulated data slightly deviating from the true model are used to show the developed method's statistical efficacy at the assumed stochastic model, its robustness against the deviations from the assumed stochastic model, and the validity of the estimated variance-covariance matrix no matter whether the assumed stochastic model is correct or not.

Mixed H2/H∞-Based Fusion Estimation for Energy-Limited Multi-Sensors in Wearable Body Networks

Directory of Open Access Journals (Sweden)

Chao Li

2017-12-01

Full Text Available In wireless sensor networks, sensor nodes collect plenty of data for each time period. If all of data are transmitted to a Fusion Center (FC, the power of sensor node would run out rapidly. On the other hand, the data also needs a filter to remove the noise. Therefore, an efficient fusion estimation model, which can save the energy of the sensor nodes while maintaining higher accuracy, is needed. This paper proposes a novel mixed H2/H∞-based energy-efficient fusion estimation model (MHEEFE for energy-limited Wearable Body Networks. In the proposed model, the communication cost is firstly reduced efficiently while keeping the estimation accuracy. Then, the parameters in quantization method are discussed, and we confirm them by an optimization method with some prior knowledge. Besides, some calculation methods of important parameters are researched which make the final estimates more stable. Finally, an iteration-based weight calculation algorithm is presented, which can improve the fault tolerance of the final estimate. In the simulation, the impacts of some pivotal parameters are discussed. Meanwhile, compared with the other related models, the MHEEFE shows a better performance in accuracy, energy-efficiency and fault tolerance.

Estimating limits for natural human embryo mortality [version 2; referees: 2 approved

Directory of Open Access Journals (Sweden)

Gavin E. Jarvis

2016-12-01

Full Text Available Natural human embryonic mortality is generally considered to be high. Values of 70% and higher are widely cited. However, it is difficult to determine accurately owing to an absence of direct data quantifying embryo loss between fertilisation and implantation. The best available data for quantifying pregnancy loss come from three published prospective studies (Wilcox, Zinaman and Wang with daily cycle by cycle monitoring of human chorionic gonadotrophin (hCG in women attempting to conceive. Declining conception rates cycle by cycle in these studies indicate that a proportion of the study participants were sub-fertile. Hence, estimates of fecundability and pre-implantation embryo mortality obtained from the whole study cohort will inevitably be biased. This new re-analysis of aggregate data from these studies confirms the impression that discrete fertile and sub-fertile sub-cohorts were present. The proportion of sub-fertile women in the three studies was estimated as 28.1% (Wilcox, 22.8% (Zinaman and 6.0% (Wang. The probability of conceiving an hCG pregnancy (indicating embryo implantation was, respectively, 43.2%, 38.1% and 46.2% among normally fertile women, and 7.6%, 2.5% and 4.7% among sub-fertile women. Pre-implantation loss is impossible to calculate directly from available data although plausible limits can be estimated. Based on this new analysis and a model for evaluating reproductive success and failure it is proposed that a plausible range for normal human embryo and fetal mortality from fertilisation to birth is 40-60%.

RADII OF RAPIDLY ROTATING STARS, WITH APPLICATION TO TRANSITING-PLANET HOSTS

International Nuclear Information System (INIS)

Brown, Timothy M.

2010-01-01

The currently favored method for estimating radii and other parameters of transiting-planet host stars is to match theoretical models to observations of the stellar mean density ρ * , the effective temperature T eff , and the composition parameter [Z]. This explicitly model-dependent approach is based on readily available observations, and results in small formal errors. Its performance will be central to the reliability of results from ground-based transit surveys such as TrES, HAT, and SuperWASP, as well as to the space-borne missions MOST, CoRoT, and Kepler. Here, I use two calibration samples of stars (eclipsing binaries (EBs) and stars for which asteroseismic analyses are available) having well-determined masses and radii to estimate the accuracy and systematic errors inherent in the ρ * method. When matching to the Yonsei-Yale stellar evolution models, I find the most important systematic error results from selection bias favoring rapidly rotating (hence probably magnetically active) stars among the EB sample. If unaccounted for, this bias leads to a mass-dependent underestimate of stellar radii by as much as 4% for stars of 0.4 M sun , decreasing to zero for masses above about 1.4 M sun . Relative errors in estimated stellar masses are three times larger than those in radii. The asteroseismic sample suggests (albeit with significant uncertainty) that systematic errors are small for slowly rotating, inactive stars. Systematic errors arising from failings of the Yonsei-Yale models of inactive stars probably exist, but are difficult to assess because of the small number of well-characterized comparison stars having low mass and slow rotation. Poor information about [Z] is an important source of random error, and may be a minor source of systematic error as well. With suitable corrections for rotation, it is likely that systematic errors in the ρ * method can be comparable to or smaller than the random errors, yielding radii that are accurate to about 2% for

Age- and sex-specific reference limits for creatinine, cystatin C and the estimated glomerular filtration rate.

Science.gov (United States)

Hannemann, Anke; Friedrich, Nele; Dittmann, Kathleen; Spielhagen, Christin; Wallaschofski, Henri; Völzke, Henry; Rettig, Rainer; Endlich, Karlhans; Lendeckel, Uwe; Stracke, Sylvia; Nauck, Matthias

2011-11-14

Early detection of patients with chronic kidney disease is of great importance. This study developed reference limits for serum creatinine and serum cystatin C concentrations and for the estimated glomerular filtration rate (eGFR) in healthy subjects from the general population aged 25-65 years. This study defined a reference population including 985 subjects from the first follow-up of the Study of Health in Pomerania. Serum creatinine was measured with a modified kinetic Jaffé method. Serum cystatin C was measured with a nephelometric assay. The eGFR was calculated from serum creatinine according to the Cockcroft-Gault (eGFR(CG)) and the Modification of Diet in Renal Disease (eGFR(MDRD)) equation, respectively, as well as from serum cystatin C according to the formula by Larsson (eGFR(Larsson)). Non-parametric quantile regression was used to estimate the reference limits. For serum creatinine and serum cystatin C the 95th percentile and for eGFR(CG), eGFR(MDRD) and eGFR(Larsson) the 5th percentile were selected as reference limits. All data was weighted to reflect the age- and sex-structure of the German population in 2008. The reference limits for serum creatinine (men: 1.11-1.23 mg/dL; women: 0.93-1.00 mg/dL) and serum cystatin C levels (men: 0.92-1.04 mg/L; women: 0.84-1.02 mg/L) increased with advancing age. The reference limits for eGFR decreased with increasing age (eGFR(CG) men: 106.0-64.7 mL/min, women 84.4-57.9 mL/min; eGFR(MDRD) men: 82.5-62.2 mL/min/1.73 m², women 75.0-58.2 mL/min/1.73 m²; eGFR(Larsson) men: 85.5-72.9 mL/min, women 94.5-75.7 mL/min). This study presents age- and sex-specific reference limits for five measures of renal function based on quantile regression models.

Extended I-Love relations for slowly rotating neutron stars

Science.gov (United States)

Gagnon-Bischoff, Jérémie; Green, Stephen R.; Landry, Philippe; Ortiz, Néstor

2018-03-01

Observations of gravitational waves from inspiralling neutron star binaries—such as GW170817—can be used to constrain the nuclear equation of state by placing bounds on stellar tidal deformability. For slowly rotating neutron stars, the response to a weak quadrupolar tidal field is characterized by four internal-structure-dependent constants called "Love numbers." The tidal Love numbers k2el and k2mag measure the tides raised by the gravitoelectric and gravitomagnetic components of the applied field, and the rotational-tidal Love numbers fo and ko measure those raised by couplings between the applied field and the neutron star spin. In this work, we compute these four Love numbers for perfect fluid neutron stars with realistic equations of state. We discover (nearly) equation-of-state independent relations between the rotational-tidal Love numbers and the moment of inertia, thereby extending the scope of I-Love-Q universality. We find that similar relations hold among the tidal and rotational-tidal Love numbers. These relations extend the applications of I-Love universality in gravitational-wave astronomy. As our findings differ from those reported in the literature, we derive general formulas for the rotational-tidal Love numbers in post-Newtonian theory and confirm numerically that they agree with our general-relativistic computations in the weak-field limit.

Geometric phase for a neutral particle in rotating frames in a cosmic string spacetime

International Nuclear Information System (INIS)

Bakke, Knut; Furtado, Claudio

2009-01-01

We study of the appearance of geometric quantum phases in the dynamics of a neutral particle that possess a permanent magnetic dipole moment in rotating frames in a cosmic string spacetime. The relativistic dynamics of spin-1/2 particle in this frame is investigated and we obtain several contributions to relativistic geometric phase due rotation and topology of spacetime. We also study the geometric phase in the nonrelativistic limit. We obtain effects analogous to the Sagnac effect and Mashhoon effect in a rotating frame in the background of a cosmic string.

Fireball flickering: the case for indirect measurement of meteoroid rotation rates

Science.gov (United States)

Beech, Martin; Brown, Peter

2000-08-01

Data collected during the Meteorite Observation and Recovery Program (MORP) indicate that 4% of bright fireballs show a periodic variation or flickering in brightness. The observed flickering frequencies vary from a few Hz to as high as 500 Hz. We interpret the flickering phenomenon in terms of meteoroid rotation. The MORP data does not reveal any apparent correlation between the flickering frequency and the properties of the meteoroid or the atmospheric flow conditions under which ablation is taking place. It is argued that the most likely cause of the flickering phenomenon is the rotational modulation of the cross-section area presented by the meteoroid to the on-coming airflow. A study is made of the Peekskill fireball and it is concluded that the meteoroid was spun-up during its long flight through the Earth's atmosphere, and that its initial brake up was due to rotational bursting. We also argue that the Peekskill event provides the best observational evidence that the flickering phenomenon is truly related to the rotation rate of the impinging meteoroid. We find that the observed rotation rates of the MORP fireballs are clustered just below the allowed limit set by rotational bursting, but argue that this is due to an observational selection effect that mitigates against the detection of low-frequency flickering.

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1977-01-01

History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

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.

Analysis of the rotation accident of assemblies in boiling water reactors

International Nuclear Information System (INIS)

Becerril-Gonzalez M, J. J.; Fuentes M, L.; Castillo M, J. A.; Ortiz S, J. J.; Perusquia de Cueto, R.

2012-10-01

For this work was analyzed the impact that would cause the load of a rotated fuel assembly in the behaviour of the core in the Cycle 14 of the Unit 1 of the nuclear power plant of Laguna Verde. To carry out this analysis the code Simulate-3 was used, with which was possible to analyze the behavior of the effective multiplication factor and the thermal limits (MAPRAT, MFLPD and MFLCPR). The rotation of fuel assemblies to 90, 180 and 270 grades was analyzed with regard to the design position, with 0, 1, 2 and 3 burnt cycles for these assemblies. The results show that the thermal limits remain inside the allowed values, therefore if this accident type happened the reactor could continue operating in a sure way. (Author)

Effect of rotation on convective mass transfer in rotating channels

International Nuclear Information System (INIS)

Pharoah, J.G.; Djilali, N.

2002-01-01

Laminar flow and mass transfer in rotating channels is investigated in the context of centrifugal membrane separation. The effect of orientation with respect to the rotational axis is examined for rectangular channels of aspect ratio 3 and the Rossby number is varied from 0.3 to 20.9. Both Ro and the channel orientation are found to have a significant effect on the flow. Mass transfer calculations corresponding to reverse osmosis desalination are carried out at various operating pressures and all rotating cases exhibit significant process enhancements at relatively low rotation rates. Finally, while it is common in the membrane literature to correlate mass transfer performance with membrane shear rates this is shown not to be valid in the cases presented herein. (author)

Reconstructing plate-motion changes in the presence of finite-rotations noise.

Science.gov (United States)

Iaffaldano, Giampiero; Bodin, Thomas; Sambridge, Malcolm

2012-01-01

Understanding lithospheric plate motions is of paramount importance to geodynamicists. Much effort is going into kinematic reconstructions featuring progressively finer temporal resolution. However, the challenge of precisely identifying ocean-floor magnetic lineations, and uncertainties in geomagnetic reversal timescales result in substantial finite-rotations noise. Unless some type of temporal smoothing is applied, the scenario arising at the native temporal resolution is puzzling, as plate motions vary erratically and significantly over short periods (<1 Myr). This undermines our ability to make geodynamic inferences, as the rates at which forces need to be built upon plates to explain these kinematics far exceed the most optimistic estimates. Here we show that the largest kinematic changes reconstructed across the Atlantic, Indian and South Pacific ridges arise from data noise. We overcome this limitation using a trans-dimensional hierarchical Bayesian framework. We find that plate-motion changes occur on timescales no shorter than a few million years, yielding simpler kinematic patterns and more plausible dynamics.

Experimental studies of rotating exchange flow

Science.gov (United States)

Rabe, B.; Smeed, D. A.; Dalziel, S. B.; Lane-Serff, G. F.

2007-02-01

Ocean basins are connected by straits and passages, geometrically limiting important heat and salt exchanges which in turn influence the global thermohaline circulation and climate. Such exchange can be modeled in an idealized way by taking into consideration the density-driven two-layer flow along a strait under the influence of rotation. We use a laboratory model of a lock exchange between two reservoirs of different density through a flat-bottom channel with a horizontal narrows, set up on two different platforms: a 1 m diameter turntable, where density interface position was measured by dye attenuation, and the 14 m diameter turntable at Coriolis/LEGI (Grenoble, France), where correlation imaging velocimetry, a particle imaging technique, allowed us to obtain for the first time detailed measurements of the velocity fields in these flows. The influence of rotation is studied by varying a parameter, Bu, a type of Burger number given by the ratio of the Rossby radius to the channel width at the narrows. In addition, a two-layer version of the Miami Isopycnic Coordinate Model (MICOM) is used, to study the cases with low Burger number. Results from experiments by Dalziel [1988. Two-layer hydraulics: maximal exchange flows. Ph.D. Thesis, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, see also people/sd103/papers/1988/Thesis_Dalziel.pdf>] are also included for comparison. Time-mean exchange fluxes for any Bu are in close agreement with the inviscid zero-potential vorticity theory of Dalziel [1990. Rotating two-layer sill flows. In: Pratt, L.J. (Ed.), The Physical Oceanography of Sea Straits. Kluwer Academic, Dordrecht, pp. 343-371] and Whitehead et al. [1974. Rotating hydraulics of strait and sill flows. Geophysical Fluid Dynamics 6, 101-125], who found that fluxes for Bu>1 mainly vary with channel width, similar to non-rotating flow, but for Bu1 a steady, two-layer flow was observed that persisted across the channel at the narrows

P-shaped Coiled Stator Ultrasound Motor for Rotating Intravascular Surgery Device

Directory of Open Access Journals (Sweden)

Toshinobu ABE

2015-01-01

Full Text Available The primary focus of this paper is the development of an ultra-miniature ultrasound motor for use in the human blood vessel. Since the size of the drive source for rotating the atherectomy device and intravascular ultrasonography system are large currently in practical use, it is installed outside the body, and the rotational power for the atherectomy device and intravascular ultrasonography system are transmitted through the long tortuous blood vessel. Such systems suffer from the problem that the rotation becomes non-uniform, and the problem that the available time is limited. We have therefore developed a P-shaped coiled stator ultrasound motor as a miniature ultrasound motor for rotating the ultrasound sensor for use in blood vessels in order to solve these problems. In this paper, we describe measurement of the torque, revolution speed, output power, efficiency, and particle motion on acoustic waveguide of the P-shaped coiled stator ultrasound motor.

A fluid Foucault pendulum: the impossibility of achieving solid-body rotation on Earth

Science.gov (United States)

Blum, Robert; Zimmerman, Daniel; Triana, Santiago; Lathrop, Daniel

2012-11-01

Rotating fluid dynamics is key to our understanding of the Earth's atmosphere, oceans, and core, along with a plethora of astrophysical objects. Laboratory study of these natural systems often involves spinning experimental devices, which are assumed to tend to rigid rotation when unstirred. We present results showing that even at the tabletop scale, there is a measurable oscillatory flow driven by the precession of the experiment's axis as the earth rotates. We measure this flow in a rotating cylinder with an adjustable aspect ratio. The horizontal flow in the rotating frame is measured using particle tracking. The steady state is well-described by an inertial mode whose amplitude is maximum when the height to diameter ratio is 0.995, which matches theoretical predictions. We also quantify the resonant amplitude of the inertial mode in the cylinder and estimate the amplitude in other devices. We compare our results to similar studies done in spherical devices. [Triana et al., JGR, 117 (2012), B04103][Boisson et al., EPL, 98 (2012), 59002].

An SVM-Based Classifier for Estimating the State of Various Rotating Components in Agro-Industrial Machinery with a Vibration Signal Acquired from a Single Point on the Machine Chassis

Directory of Open Access Journals (Sweden)

Ruben Ruiz-Gonzalez

2014-11-01

Full Text Available The goal of this article is to assess the feasibility of estimating the state of various rotating components in agro-industrial machinery by employing just one vibration signal acquired from a single point on the machine chassis. To do so, a Support Vector Machine (SVM-based system is employed. Experimental tests evaluated this system by acquiring vibration data from a single point of an agricultural harvester, while varying several of its working conditions. The whole process included two major steps. Initially, the vibration data were preprocessed through twelve feature extraction algorithms, after which the Exhaustive Search method selected the most suitable features. Secondly, the SVM-based system accuracy was evaluated by using Leave-One-Out cross-validation, with the selected features as the input data. The results of this study provide evidence that (i accurate estimation of the status of various rotating components in agro-industrial machinery is possible by processing the vibration signal acquired from a single point on the machine structure; (ii the vibration signal can be acquired with a uniaxial accelerometer, the orientation of which does not significantly affect the classification accuracy; and, (iii when using an SVM classifier, an 85% mean cross-validation accuracy can be reached, which only requires a maximum of seven features as its input, and no significant improvements are noted between the use of either nonlinear or linear kernels.

Earth Rotation

Science.gov (United States)

Dickey, Jean O.

1995-01-01

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

Generation of a rotating liquid liner by tangential injection

International Nuclear Information System (INIS)

Burton, R.L.; Turchi, P.J.; Jenkins, D.J.; Lanham, R.E.; Cameron, J.; Cooper, A.L.

1979-01-01

Efficient compression of low mass-density payloads by the implosion of higher mass-density liquid cylinders or liners, as in the NRL LINUS concept for controlled thermonuclear fusion, requires rotation of the liner material to avoid Rayleigh--Taylor instabilities at the liner-payload interface. Experimentally, such implosions have been demonstrated with liners formed within rotating implosion chambers. The present work uses a scale-model experimental apparatus to investigate the possibility of creating liner rotation by tangential injection of the liquid liner material. Different modes of behavior are obtained depending on the fluid exhaust procedures. Right-circular, cylindrical free surfaces are achieved with axial exhaust of fluid at radii interior to the injection nozzles, for which the liner exhibits a combination of solid-body and free vortex flows in different regions. Measurements allow estimates of power losses to viscous shear, turbulence, etc. A simple model based on open-channel flow is then derived, which is in good agreement with experiment, and is used to extrapolate results to the scale of a possible LINUS fusion reactor

High-accuracy self-calibration method for dual-axis rotation-modulating RLG-INS

Science.gov (United States)

Wei, Guo; Gao, Chunfeng; Wang, Qi; Wang, Qun; Long, Xingwu

2017-05-01

Inertial navigation system has been the core component of both military and civil navigation systems. Dual-axis rotation modulation can completely eliminate the inertial elements constant errors of the three axes to improve the system accuracy. But the error caused by the misalignment angles and the scale factor error cannot be eliminated through dual-axis rotation modulation. And discrete calibration method cannot fulfill requirements of high-accurate calibration of the mechanically dithered ring laser gyroscope navigation system with shock absorbers. This paper has analyzed the effect of calibration error during one modulated period and presented a new systematic self-calibration method for dual-axis rotation-modulating RLG-INS. Procedure for self-calibration of dual-axis rotation-modulating RLG-INS has been designed. The results of self-calibration simulation experiment proved that: this scheme can estimate all the errors in the calibration error model, the calibration precision of the inertial sensors scale factor error is less than 1ppm and the misalignment is less than 5″. These results have validated the systematic self-calibration method and proved its importance for accuracy improvement of dual -axis rotation inertial navigation system with mechanically dithered ring laser gyroscope.

Rotator cuff tears in children and adolescents: experience at a large pediatric hospital

International Nuclear Information System (INIS)

Zbojniewicz, Andrew M.; Emery, Kathleen H.; Maeder, Matthew E.; Salisbury, Shelia R.

2014-01-01

Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation. The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes. We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available. Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between

Rotator cuff tears in children and adolescents: experience at a large pediatric hospital

Energy Technology Data Exchange (ETDEWEB)

Zbojniewicz, Andrew M.; Emery, Kathleen H. [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Maeder, Matthew E. [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Lenox Hill Hospital, Department of Radiology, New York, NY (United States); Salisbury, Shelia R. [University of Cincinnati College of Medicine, Division of Biostatistics and Epidemiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States)

2014-06-15

Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation. The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes. We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available. Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between

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....

Rotating dryer

International Nuclear Information System (INIS)

Noe, C.

1984-01-01

Products to dry are introduced inside a rotating tube placed in an oven, the cross section of the tube is an arc of spiral. During clockwise rotation of the tube products are maintained inside and mixed, during anticlockwise products are removed. Application is made to drying of radioactive wastes [fr

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…

A Rotating Plug Model of Friction Stir Welding Heat Transfer

Science.gov (United States)

Raghulapadu J. K.; Peddieson, J.; Buchanan, G. R.; Nunes, A. C.

2006-01-01

A simplified rotating plug model is employed to study the heat transfer phenomena associated with the fiction stir welding process. An approximate analytical solution is obtained based on this idealized model and used both to demonstrate the qualitative influence of process parameters on predictions and to estimate temperatures produced in typical fiction stir welding situations.

Imaging characteristics in rotational panoramic radiography

International Nuclear Information System (INIS)

Sanderink, G.C.H.

1987-01-01

This study is concerned with imaging quality in rotational panoramic radiography. This imaging technique records an image of a curved layer within the object radiographed. The shape of this layer normally corresponds with the average form of the dental arch. In the centre of the layer a plane can be found which is depicted with a minimum of unsharpness. Unsharpness increases and the horizontal magnification changes as distance increases from that central plane. The image quality of the layer has been analyzed with the use of mathematical models to estimate the performance of the radiographic diagnostic system. Despite the application of these increasingly sophisticated models the question remains: will the results of the calculations based on these models adequately predict the diagnostic effectiveness of this type of imaging system? In this study a comparison is made between the theoretically determined quality of the system and the diagnostic quality using the observer as a measuring instrument. Experiments were carried out to measure the total unsharpness occurring in rotational panoramic radiography. 116 refs.; 114 figs.; 54 tabs

Rotator cuff - self-care

Science.gov (United States)

... this page: //medlineplus.gov/ency/patientinstructions/000358.htm Rotator cuff - self-care To use the sharing features on ... and shoulder exercises may help ease your symptoms. Rotator Cuff Problems Common rotator cuff problems include: Tendinitis , which ...

Estimating landscape-scale impacts of agricultural management on soil carbon using measurements and models

Science.gov (United States)

Schipanski, M.; Rosenzweig, S. T.; Robertson, A. D.; Sherrod, L. A.; Ghimire, R.; McMaster, G. S.

2017-12-01

Agriculture covers 40% of Earth's ice-free land area and has broad impacts on global biogeochemical cycles. While some agricultural management changes are small in scale or impact, others have the potential to shift biogeochemical cycles at landscape and larger scales if widely adopted. Understanding which management practices have the potential to contribute to climate change adaptation and mitigation while maintaining productivity requires scaling up estimates spatially and temporally. We used on-farm, long-term, and landscape scale datasets to estimate how crop rotations impact soil organic carbon (SOC) accumulation rates under current and future climate scenarios across the semi-arid Central and Southern Great Plains. We used a stratified, landscape-scale soil sampling approach across 96 farm fields to evaluate crop rotation intensity effects on SOC pools and pesticide inputs. Replacing traditional wheat-fallow rotations with more diverse, continuously cropped rotations increased SOC by 17% and 12% in 0-10 cm and 0-20 cm depths, respectively, and reduced herbicide use by 50%. Using USDA Cropland Data Layer, we estimated soil C accumulation and pesticide reduction potentials of shifting to more intensive rotations. We also used a 30-year cropping systems experiment to calibrate and validate the Daycent model to evaluate rotation intensify effects under future climate change scenarios. The model estimated greater SOC accumulation rates under continuously cropped rotations, but SOC stocks peaked and then declined for all cropping systems beyond 2050 under future climate scenarios. Perennial grasslands were the only system estimated to maintain SOC levels in the future. In the Southern High Plains, soil C declined despite increasing input intensity under current weather while modest gains were simulated under future climate for sorghum-based cropping systems. Our findings highlight the potential vulnerability of semi-arid regions to climate change, which will be

Effects of suspended particles on the rate of mass transfer to a rotating disk electrode. [Ferric cyanide

Energy Technology Data Exchange (ETDEWEB)

Roha, D.J.

1981-06-01

Limiting currents for the reduction of ferric cyanide at a rotating disk were determined in the presence of 0 to 40 percent by volume of spherical glass beads. Experiments were conducted with six different particle diameters, and with rotation speeds in the range of 387 to 270 rpm, usong both a 0.56 cm and a 1.41 cm radius disk electrode. It was established that at a given rpm upon addition of glass beads in the limiting current, i/sub L/, may increase to more than three times its value without solids. This increase in limiting current density is greater at high rotation speeds and with the larger disk electrode. i/sub L/ as a function of particle diameter yields at maximum at approx. 10 ..mu..m. Two mass transfer models are offered to explain this behavior, both of which assume that the beads are in contact with the disk electrode and moving parallel to its surface. In the surface renewal model it is assumed that complete mixing takes place with the passage of each bead and the boundary layer is replaced with fresh bulk solution. While with the particle film model it is assumed the bead and a clinging film of fluid rotate together. The film promotes mass transfer by alternately absorbing and desorbing the diffusing species. The particle film model best explains the observed behavior of the limiting current density. Calculations of stirring power required verses i/sub L/ observed, show that adding beads to increase i/sub L/ consumes less additional power than simply increasing the rotation speed alone and even permits a decrease in the amount of stirring energy required per unit reactant consumed, at limiting current conditions.

When a Slowly Rotating Aquaplanet is Coupled to a Dynamical Ocean

Science.gov (United States)

Salameh, J.; Marotzke, J.

2017-12-01

Planets orbiting in close distance from their stars have a high probability to be detected, and are expected to be slowly rotating due to strong tidal forces. By increasing the rotation period from 1 Earth-day to 365 Earth-days, we previously found that the global-mean surface temperature of an aquaplanet with a static mixed-layer ocean decreases by up to 27 K. The cooling is attributed to an increase of the planetary albedo with the rotation period, which is associated with the different distributions of the sea ice and the deep convective clouds. However, we had there assumed a fixed mixed-layer depth and a zero oceanic heat transport in the aquaplanet configuration. The limitations of these assumptions in such exotic climates are still unclear. We therefore perform coupled atmosphere-ocean aquaplanet simulations with the general circulation model ICON for various rotation periods ranging from 1 Earth-day to 365 Earth-days. We investigate how the underlying oceanic circulation modifies the mean climate of slowly rotating aquaplanets, and whether the day-to-night oceanic heat transport reduces the surface-temperature gradients and the sea-ice extent.

The Fastest Rotating Pulsar: a Strange Star?

Institute of Scientific and Technical Information of China (English)

徐仁新; 徐轩彬; 吴鑫基

2001-01-01

According to the observational limits on the radius and mass, the fastest rotating pulsar (PSR 1937+21) is probably a strange star, or at least some neutron star equations of state should be ruled out, if we suggest that a dipole magnetic field is relevant to its radio emission. We presume that the millisecond pulsar is a strange star with much low mass, small radius and weak magnetic moment.

Evaluation of Different Phenological Information to Map Crop Rotation in Complex Irrigated Indus Basin

Science.gov (United States)

Ismaeel, A.; Zhou, Q.

2018-04-01

Accurate information of crop rotation in large basin is essential for policy decisions on land, water and nutrient resources around the world. Crop area estimation using low spatial resolution remote sensing data is challenging in a large heterogeneous basin having more than one cropping seasons. This study aims to evaluate the accuracy of two phenological datasets individually and in combined form to map crop rotations in complex irrigated Indus basin without image segmentation. Phenology information derived from Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) of Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, having 8-day temporal and 1000 m spatial resolution, was used in the analysis. An unsupervised (temporal space clustering) to supervised (area knowledge and phenology behavior) classification approach was adopted to identify 13 crop rotations. Estimated crop area was compared with reported area collected by field census. Results reveal that combined dataset (NDVI*LAI) performs better in mapping wheat-rice, wheat-cotton and wheat-fodder rotation by attaining root mean square error (RMSE) of 34.55, 16.84, 20.58 and mean absolute percentage error (MAPE) of 24.56 %, 36.82 %, 30.21 % for wheat, rice and cotton crop respectively. For sugarcane crop mapping, LAI produce good results by achieving RMSE of 8.60 and MAPE of 34.58 %, as compared to NDVI (10.08, 40.53 %) and NDVI*LAI (10.83, 39.45 %). The availability of major crop rotation statistics provides insight to develop better strategies for land, water and nutrient accounting frameworks to improve agriculture productivity.

EVALUATION OF DIFFERENT PHENOLOGICAL INFORMATION TO MAP CROP ROTATION IN COMPLEX IRRIGATED INDUS BASIN

Directory of Open Access Journals (Sweden)

A. Ismaeel

2018-04-01

Full Text Available Accurate information of crop rotation in large basin is essential for policy decisions on land, water and nutrient resources around the world. Crop area estimation using low spatial resolution remote sensing data is challenging in a large heterogeneous basin having more than one cropping seasons. This study aims to evaluate the accuracy of two phenological datasets individually and in combined form to map crop rotations in complex irrigated Indus basin without image segmentation. Phenology information derived from Normalized Difference Vegetation Index (NDVI and Leaf Area Index (LAI of Moderate Resolution Imaging Spectroradiometer (MODIS sensor, having 8-day temporal and 1000 m spatial resolution, was used in the analysis. An unsupervised (temporal space clustering to supervised (area knowledge and phenology behavior classification approach was adopted to identify 13 crop rotations. Estimated crop area was compared with reported area collected by field census. Results reveal that combined dataset (NDVI*LAI performs better in mapping wheat-rice, wheat-cotton and wheat-fodder rotation by attaining root mean square error (RMSE of 34.55, 16.84, 20.58 and mean absolute percentage error (MAPE of 24.56 %, 36.82 %, 30.21 % for wheat, rice and cotton crop respectively. For sugarcane crop mapping, LAI produce good results by achieving RMSE of 8.60 and MAPE of 34.58 %, as compared to NDVI (10.08, 40.53 % and NDVI*LAI (10.83, 39.45 %. The availability of major crop rotation statistics provides insight to develop better strategies for land, water and nutrient accounting frameworks to improve agriculture productivity.

Rotating Stars in Relativity

Directory of Open Access Journals (Sweden)

Stergioulas Nikolaos

2003-01-01

Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.